fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/aio.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.h>
  40 #include <linux/slab.h>
  41 #include <linux/ratelimit.h>
  42 #include <linux/mount.h>
  43 #include <linux/btrfs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/posix_acl_xattr.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62
  63 struct btrfs_iget_args {
  64         struct btrfs_key *location;
  65         struct btrfs_root *root;
  66 };
  67
  68 static const struct inode_operations btrfs_dir_inode_operations;
  69 static const struct inode_operations btrfs_symlink_inode_operations;
  70 static const struct inode_operations btrfs_dir_ro_inode_operations;
  71 static const struct inode_operations btrfs_special_inode_operations;
  72 static const struct inode_operations btrfs_file_inode_operations;
  73 static const struct address_space_operations btrfs_aops;
  74 static const struct address_space_operations btrfs_symlink_aops;
  75 static const struct file_operations btrfs_dir_file_operations;
  76 static struct extent_io_ops btrfs_extent_io_ops;
  77
  78 static struct kmem_cache *btrfs_inode_cachep;
  79 static struct kmem_cache *btrfs_delalloc_work_cachep;
  80 struct kmem_cache *btrfs_trans_handle_cachep;
  81 struct kmem_cache *btrfs_transaction_cachep;
  82 struct kmem_cache *btrfs_path_cachep;
  83 struct kmem_cache *btrfs_free_space_cachep;
  84
  85 #define S_SHIFT 12
  86 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  87         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  88         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  89         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  90         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  91         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  92         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  93         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  94 };
  95
  96 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  97 static int btrfs_truncate(struct inode *inode);
  98 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  99 static noinline int cow_file_range(struct inode *inode,
 100                                    struct page *locked_page,
 101                                    u64 start, u64 end, int *page_started,
 102                                    unsigned long *nr_written, int unlock);
 103 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 104                                            u64 len, u64 orig_start,
 105                                            u64 block_start, u64 block_len,
 106                                            u64 orig_block_len, u64 ram_bytes,
 107                                            int type);
 108
 109 static int btrfs_dirty_inode(struct inode *inode);
 110
 111 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 112                                      struct inode *inode,  struct inode *dir,
 113                                      const struct qstr *qstr)
 114 {
 115         int err;
 116
 117         err = btrfs_init_acl(trans, inode, dir);
 118         if (!err)
 119                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 120         return err;
 121 }
 122
 123 /*
 124  * this does all the hard work for inserting an inline extent into
 125  * the btree.  The caller should have done a btrfs_drop_extents so that
 126  * no overlapping inline items exist in the btree
 127  */
 128 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 129                                 struct btrfs_path *path, int extent_inserted,
 130                                 struct btrfs_root *root, struct inode *inode,
 131                                 u64 start, size_t size, size_t compressed_size,
 132                                 int compress_type,
 133                                 struct page **compressed_pages)
 134 {
 135         struct extent_buffer *leaf;
 136         struct page *page = NULL;
 137         char *kaddr;
 138         unsigned long ptr;
 139         struct btrfs_file_extent_item *ei;
 140         int err = 0;
 141         int ret;
 142         size_t cur_size = size;
 143         unsigned long offset;
 144
 145         if (compressed_size && compressed_pages)
 146                 cur_size = compressed_size;
 147
 148         inode_add_bytes(inode, size);
 149
 150         if (!extent_inserted) {
 151                 struct btrfs_key key;
 152                 size_t datasize;
 153
 154                 key.objectid = btrfs_ino(inode);
 155                 key.offset = start;
 156                 key.type = BTRFS_EXTENT_DATA_KEY;
 157
 158                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 159                 path->leave_spinning = 1;
 160                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 161                                               datasize);
 162                 if (ret) {
 163                         err = ret;
 164                         goto fail;
 165                 }
 166         }
 167         leaf = path->nodes[0];
 168         ei = btrfs_item_ptr(leaf, path->slots[0],
 169                             struct btrfs_file_extent_item);
 170         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 171         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 172         btrfs_set_file_extent_encryption(leaf, ei, 0);
 173         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 174         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 175         ptr = btrfs_file_extent_inline_start(ei);
 176
 177         if (compress_type != BTRFS_COMPRESS_NONE) {
 178                 struct page *cpage;
 179                 int i = 0;
 180                 while (compressed_size > 0) {
 181                         cpage = compressed_pages[i];
 182                         cur_size = min_t(unsigned long, compressed_size,
 183                                        PAGE_CACHE_SIZE);
 184
 185                         kaddr = kmap_atomic(cpage);
 186                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 187                         kunmap_atomic(kaddr);
 188
 189                         i++;
 190                         ptr += cur_size;
 191                         compressed_size -= cur_size;
 192                 }
 193                 btrfs_set_file_extent_compression(leaf, ei,
 194                                                   compress_type);
 195         } else {
 196                 page = find_get_page(inode->i_mapping,
 197                                      start >> PAGE_CACHE_SHIFT);
 198                 btrfs_set_file_extent_compression(leaf, ei, 0);
 199                 kaddr = kmap_atomic(page);
 200                 offset = start & (PAGE_CACHE_SIZE - 1);
 201                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 202                 kunmap_atomic(kaddr);
 203                 page_cache_release(page);
 204         }
 205         btrfs_mark_buffer_dirty(leaf);
 206         btrfs_release_path(path);
 207
 208         /*
 209          * we're an inline extent, so nobody can
 210          * extend the file past i_size without locking
 211          * a page we already have locked.
 212          *
 213          * We must do any isize and inode updates
 214          * before we unlock the pages.  Otherwise we
 215          * could end up racing with unlink.
 216          */
 217         BTRFS_I(inode)->disk_i_size = inode->i_size;
 218         ret = btrfs_update_inode(trans, root, inode);
 219
 220         return ret;
 221 fail:
 222         return err;
 223 }
 224
 225
 226 /*
 227  * conditionally insert an inline extent into the file.  This
 228  * does the checks required to make sure the data is small enough
 229  * to fit as an inline extent.
 230  */
 231 static noinline int cow_file_range_inline(struct btrfs_root *root,
 232                                           struct inode *inode, u64 start,
 233                                           u64 end, size_t compressed_size,
 234                                           int compress_type,
 235                                           struct page **compressed_pages)
 236 {
 237         struct btrfs_trans_handle *trans;
 238         u64 isize = i_size_read(inode);
 239         u64 actual_end = min(end + 1, isize);
 240         u64 inline_len = actual_end - start;
 241         u64 aligned_end = ALIGN(end, root->sectorsize);
 242         u64 data_len = inline_len;
 243         int ret;
 244         struct btrfs_path *path;
 245         int extent_inserted = 0;
 246         u32 extent_item_size;
 247
 248         if (compressed_size)
 249                 data_len = compressed_size;
 250
 251         if (start > 0 ||
 252             actual_end > PAGE_CACHE_SIZE ||
 253             data_len > BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 254             (!compressed_size &&
 255             (actual_end & (root->sectorsize - 1)) == 0) ||
 256             end + 1 < isize ||
 257             data_len > root->fs_info->max_inline) {
 258                 return 1;
 259         }
 260
 261         path = btrfs_alloc_path();
 262         if (!path)
 263                 return -ENOMEM;
 264
 265         trans = btrfs_join_transaction(root);
 266         if (IS_ERR(trans)) {
 267                 btrfs_free_path(path);
 268                 return PTR_ERR(trans);
 269         }
 270         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 271
 272         if (compressed_size && compressed_pages)
 273                 extent_item_size = btrfs_file_extent_calc_inline_size(
 274                    compressed_size);
 275         else
 276                 extent_item_size = btrfs_file_extent_calc_inline_size(
 277                     inline_len);
 278
 279         ret = __btrfs_drop_extents(trans, root, inode, path,
 280                                    start, aligned_end, NULL,
 281                                    1, 1, extent_item_size, &extent_inserted);
 282         if (ret) {
 283                 btrfs_abort_transaction(trans, root, ret);
 284                 goto out;
 285         }
 286
 287         if (isize > actual_end)
 288                 inline_len = min_t(u64, isize, actual_end);
 289         ret = insert_inline_extent(trans, path, extent_inserted,
 290                                    root, inode, start,
 291                                    inline_len, compressed_size,
 292                                    compress_type, compressed_pages);
 293         if (ret && ret != -ENOSPC) {
 294                 btrfs_abort_transaction(trans, root, ret);
 295                 goto out;
 296         } else if (ret == -ENOSPC) {
 297                 ret = 1;
 298                 goto out;
 299         }
 300
 301         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 302         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 303         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 304 out:
 305         btrfs_free_path(path);
 306         btrfs_end_transaction(trans, root);
 307         return ret;
 308 }
 309
 310 struct async_extent {
 311         u64 start;
 312         u64 ram_size;
 313         u64 compressed_size;
 314         struct page **pages;
 315         unsigned long nr_pages;
 316         int compress_type;
 317         struct list_head list;
 318 };
 319
 320 struct async_cow {
 321         struct inode *inode;
 322         struct btrfs_root *root;
 323         struct page *locked_page;
 324         u64 start;
 325         u64 end;
 326         struct list_head extents;
 327         struct btrfs_work work;
 328 };
 329
 330 static noinline int add_async_extent(struct async_cow *cow,
 331                                      u64 start, u64 ram_size,
 332                                      u64 compressed_size,
 333                                      struct page **pages,
 334                                      unsigned long nr_pages,
 335                                      int compress_type)
 336 {
 337         struct async_extent *async_extent;
 338
 339         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 340         BUG_ON(!async_extent); /* -ENOMEM */
 341         async_extent->start = start;
 342         async_extent->ram_size = ram_size;
 343         async_extent->compressed_size = compressed_size;
 344         async_extent->pages = pages;
 345         async_extent->nr_pages = nr_pages;
 346         async_extent->compress_type = compress_type;
 347         list_add_tail(&async_extent->list, &cow->extents);
 348         return 0;
 349 }
 350
 351 static inline int inode_need_compress(struct inode *inode)
 352 {
 353         struct btrfs_root *root = BTRFS_I(inode)->root;
 354
 355         /* force compress */
 356         if (btrfs_test_opt(root, FORCE_COMPRESS))
 357                 return 1;
 358         /* bad compression ratios */
 359         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 360                 return 0;
 361         if (btrfs_test_opt(root, COMPRESS) ||
 362             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 363             BTRFS_I(inode)->force_compress)
 364                 return 1;
 365         return 0;
 366 }
 367
 368 /*
 369  * we create compressed extents in two phases.  The first
 370  * phase compresses a range of pages that have already been
 371  * locked (both pages and state bits are locked).
 372  *
 373  * This is done inside an ordered work queue, and the compression
 374  * is spread across many cpus.  The actual IO submission is step
 375  * two, and the ordered work queue takes care of making sure that
 376  * happens in the same order things were put onto the queue by
 377  * writepages and friends.
 378  *
 379  * If this code finds it can't get good compression, it puts an
 380  * entry onto the work queue to write the uncompressed bytes.  This
 381  * makes sure that both compressed inodes and uncompressed inodes
 382  * are written in the same order that the flusher thread sent them
 383  * down.
 384  */
 385 static noinline void compress_file_range(struct inode *inode,
 386                                         struct page *locked_page,
 387                                         u64 start, u64 end,
 388                                         struct async_cow *async_cow,
 389                                         int *num_added)
 390 {
 391         struct btrfs_root *root = BTRFS_I(inode)->root;
 392         u64 num_bytes;
 393         u64 blocksize = root->sectorsize;
 394         u64 actual_end;
 395         u64 isize = i_size_read(inode);
 396         int ret = 0;
 397         struct page **pages = NULL;
 398         unsigned long nr_pages;
 399         unsigned long nr_pages_ret = 0;
 400         unsigned long total_compressed = 0;
 401         unsigned long total_in = 0;
 402         unsigned long max_compressed = 128 * 1024;
 403         unsigned long max_uncompressed = 128 * 1024;
 404         int i;
 405         int will_compress;
 406         int compress_type = root->fs_info->compress_type;
 407         int redirty = 0;
 408
 409         /* if this is a small write inside eof, kick off a defrag */
 410         if ((end - start + 1) < 16 * 1024 &&
 411             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 412                 btrfs_add_inode_defrag(NULL, inode);
 413
 414         actual_end = min_t(u64, isize, end + 1);
 415 again:
 416         will_compress = 0;
 417         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 418         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 419
 420         /*
 421          * we don't want to send crud past the end of i_size through
 422          * compression, that's just a waste of CPU time.  So, if the
 423          * end of the file is before the start of our current
 424          * requested range of bytes, we bail out to the uncompressed
 425          * cleanup code that can deal with all of this.
 426          *
 427          * It isn't really the fastest way to fix things, but this is a
 428          * very uncommon corner.
 429          */
 430         if (actual_end <= start)
 431                 goto cleanup_and_bail_uncompressed;
 432
 433         total_compressed = actual_end - start;
 434
 435         /*
 436          * skip compression for a small file range(<=blocksize) that
 437          * isn't an inline extent, since it dosen't save disk space at all.
 438          */
 439         if (total_compressed <= blocksize &&
 440            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 441                 goto cleanup_and_bail_uncompressed;
 442
 443         /* we want to make sure that amount of ram required to uncompress
 444          * an extent is reasonable, so we limit the total size in ram
 445          * of a compressed extent to 128k.  This is a crucial number
 446          * because it also controls how easily we can spread reads across
 447          * cpus for decompression.
 448          *
 449          * We also want to make sure the amount of IO required to do
 450          * a random read is reasonably small, so we limit the size of
 451          * a compressed extent to 128k.
 452          */
 453         total_compressed = min(total_compressed, max_uncompressed);
 454         num_bytes = ALIGN(end - start + 1, blocksize);
 455         num_bytes = max(blocksize,  num_bytes);
 456         total_in = 0;
 457         ret = 0;
 458
 459         /*
 460          * we do compression for mount -o compress and when the
 461          * inode has not been flagged as nocompress.  This flag can
 462          * change at any time if we discover bad compression ratios.
 463          */
 464         if (inode_need_compress(inode)) {
 465                 WARN_ON(pages);
 466                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 467                 if (!pages) {
 468                         /* just bail out to the uncompressed code */
 469                         goto cont;
 470                 }
 471
 472                 if (BTRFS_I(inode)->force_compress)
 473                         compress_type = BTRFS_I(inode)->force_compress;
 474
 475                 /*
 476                  * we need to call clear_page_dirty_for_io on each
 477                  * page in the range.  Otherwise applications with the file
 478                  * mmap'd can wander in and change the page contents while
 479                  * we are compressing them.
 480                  *
 481                  * If the compression fails for any reason, we set the pages
 482                  * dirty again later on.
 483                  */
 484                 extent_range_clear_dirty_for_io(inode, start, end);
 485                 redirty = 1;
 486                 ret = btrfs_compress_pages(compress_type,
 487                                            inode->i_mapping, start,
 488                                            total_compressed, pages,
 489                                            nr_pages, &nr_pages_ret,
 490                                            &total_in,
 491                                            &total_compressed,
 492                                            max_compressed);
 493
 494                 if (!ret) {
 495                         unsigned long offset = total_compressed &
 496                                 (PAGE_CACHE_SIZE - 1);
 497                         struct page *page = pages[nr_pages_ret - 1];
 498                         char *kaddr;
 499
 500                         /* zero the tail end of the last page, we might be
 501                          * sending it down to disk
 502                          */
 503                         if (offset) {
 504                                 kaddr = kmap_atomic(page);
 505                                 memset(kaddr + offset, 0,
 506                                        PAGE_CACHE_SIZE - offset);
 507                                 kunmap_atomic(kaddr);
 508                         }
 509                         will_compress = 1;
 510                 }
 511         }
 512 cont:
 513         if (start == 0) {
 514                 /* lets try to make an inline extent */
 515                 if (ret || total_in < (actual_end - start)) {
 516                         /* we didn't compress the entire range, try
 517                          * to make an uncompressed inline extent.
 518                          */
 519                         ret = cow_file_range_inline(root, inode, start, end,
 520                                                     0, 0, NULL);
 521                 } else {
 522                         /* try making a compressed inline extent */
 523                         ret = cow_file_range_inline(root, inode, start, end,
 524                                                     total_compressed,
 525                                                     compress_type, pages);
 526                 }
 527                 if (ret <= 0) {
 528                         unsigned long clear_flags = EXTENT_DELALLOC |
 529                                 EXTENT_DEFRAG;
 530                         unsigned long page_error_op;
 531
 532                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 533                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 534
 535                         /*
 536                          * inline extent creation worked or returned error,
 537                          * we don't need to create any more async work items.
 538                          * Unlock and free up our temp pages.
 539                          */
 540                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 541                                                      clear_flags, PAGE_UNLOCK |
 542                                                      PAGE_CLEAR_DIRTY |
 543                                                      PAGE_SET_WRITEBACK |
 544                                                      page_error_op |
 545                                                      PAGE_END_WRITEBACK);
 546                         goto free_pages_out;
 547                 }
 548         }
 549
 550         if (will_compress) {
 551                 /*
 552                  * we aren't doing an inline extent round the compressed size
 553                  * up to a block size boundary so the allocator does sane
 554                  * things
 555                  */
 556                 total_compressed = ALIGN(total_compressed, blocksize);
 557
 558                 /*
 559                  * one last check to make sure the compression is really a
 560                  * win, compare the page count read with the blocks on disk
 561                  */
 562                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 563                 if (total_compressed >= total_in) {
 564                         will_compress = 0;
 565                 } else {
 566                         num_bytes = total_in;
 567                 }
 568         }
 569         if (!will_compress && pages) {
 570                 /*
 571                  * the compression code ran but failed to make things smaller,
 572                  * free any pages it allocated and our page pointer array
 573                  */
 574                 for (i = 0; i < nr_pages_ret; i++) {
 575                         WARN_ON(pages[i]->mapping);
 576                         page_cache_release(pages[i]);
 577                 }
 578                 kfree(pages);
 579                 pages = NULL;
 580                 total_compressed = 0;
 581                 nr_pages_ret = 0;
 582
 583                 /* flag the file so we don't compress in the future */
 584                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 585                     !(BTRFS_I(inode)->force_compress)) {
 586                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 587                 }
 588         }
 589         if (will_compress) {
 590                 *num_added += 1;
 591
 592                 /* the async work queues will take care of doing actual
 593                  * allocation on disk for these compressed pages,
 594                  * and will submit them to the elevator.
 595                  */
 596                 add_async_extent(async_cow, start, num_bytes,
 597                                  total_compressed, pages, nr_pages_ret,
 598                                  compress_type);
 599
 600                 if (start + num_bytes < end) {
 601                         start += num_bytes;
 602                         pages = NULL;
 603                         cond_resched();
 604                         goto again;
 605                 }
 606         } else {
 607 cleanup_and_bail_uncompressed:
 608                 /*
 609                  * No compression, but we still need to write the pages in
 610                  * the file we've been given so far.  redirty the locked
 611                  * page if it corresponds to our extent and set things up
 612                  * for the async work queue to run cow_file_range to do
 613                  * the normal delalloc dance
 614                  */
 615                 if (page_offset(locked_page) >= start &&
 616                     page_offset(locked_page) <= end) {
 617                         __set_page_dirty_nobuffers(locked_page);
 618                         /* unlocked later on in the async handlers */
 619                 }
 620                 if (redirty)
 621                         extent_range_redirty_for_io(inode, start, end);
 622                 add_async_extent(async_cow, start, end - start + 1,
 623                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 624                 *num_added += 1;
 625         }
 626
 627         return;
 628
 629 free_pages_out:
 630         for (i = 0; i < nr_pages_ret; i++) {
 631                 WARN_ON(pages[i]->mapping);
 632                 page_cache_release(pages[i]);
 633         }
 634         kfree(pages);
 635 }
 636
 637 static void free_async_extent_pages(struct async_extent *async_extent)
 638 {
 639         int i;
 640
 641         if (!async_extent->pages)
 642                 return;
 643
 644         for (i = 0; i < async_extent->nr_pages; i++) {
 645                 WARN_ON(async_extent->pages[i]->mapping);
 646                 page_cache_release(async_extent->pages[i]);
 647         }
 648         kfree(async_extent->pages);
 649         async_extent->nr_pages = 0;
 650         async_extent->pages = NULL;
 651 }
 652
 653 /*
 654  * phase two of compressed writeback.  This is the ordered portion
 655  * of the code, which only gets called in the order the work was
 656  * queued.  We walk all the async extents created by compress_file_range
 657  * and send them down to the disk.
 658  */
 659 static noinline void submit_compressed_extents(struct inode *inode,
 660                                               struct async_cow *async_cow)
 661 {
 662         struct async_extent *async_extent;
 663         u64 alloc_hint = 0;
 664         struct btrfs_key ins;
 665         struct extent_map *em;
 666         struct btrfs_root *root = BTRFS_I(inode)->root;
 667         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 668         struct extent_io_tree *io_tree;
 669         int ret = 0;
 670
 671 again:
 672         while (!list_empty(&async_cow->extents)) {
 673                 async_extent = list_entry(async_cow->extents.next,
 674                                           struct async_extent, list);
 675                 list_del(&async_extent->list);
 676
 677                 io_tree = &BTRFS_I(inode)->io_tree;
 678
 679 retry:
 680                 /* did the compression code fall back to uncompressed IO? */
 681                 if (!async_extent->pages) {
 682                         int page_started = 0;
 683                         unsigned long nr_written = 0;
 684
 685                         lock_extent(io_tree, async_extent->start,
 686                                          async_extent->start +
 687                                          async_extent->ram_size - 1);
 688
 689                         /* allocate blocks */
 690                         ret = cow_file_range(inode, async_cow->locked_page,
 691                                              async_extent->start,
 692                                              async_extent->start +
 693                                              async_extent->ram_size - 1,
 694                                              &page_started, &nr_written, 0);
 695
 696                         /* JDM XXX */
 697
 698                         /*
 699                          * if page_started, cow_file_range inserted an
 700                          * inline extent and took care of all the unlocking
 701                          * and IO for us.  Otherwise, we need to submit
 702                          * all those pages down to the drive.
 703                          */
 704                         if (!page_started && !ret)
 705                                 extent_write_locked_range(io_tree,
 706                                                   inode, async_extent->start,
 707                                                   async_extent->start +
 708                                                   async_extent->ram_size - 1,
 709                                                   btrfs_get_extent,
 710                                                   WB_SYNC_ALL);
 711                         else if (ret)
 712                                 unlock_page(async_cow->locked_page);
 713                         kfree(async_extent);
 714                         cond_resched();
 715                         continue;
 716                 }
 717
 718                 lock_extent(io_tree, async_extent->start,
 719                             async_extent->start + async_extent->ram_size - 1);
 720
 721                 ret = btrfs_reserve_extent(root,
 722                                            async_extent->compressed_size,
 723                                            async_extent->compressed_size,
 724                                            0, alloc_hint, &ins, 1, 1);
 725                 if (ret) {
 726                         free_async_extent_pages(async_extent);
 727
 728                         if (ret == -ENOSPC) {
 729                                 unlock_extent(io_tree, async_extent->start,
 730                                               async_extent->start +
 731                                               async_extent->ram_size - 1);
 732
 733                                 /*
 734                                  * we need to redirty the pages if we decide to
 735                                  * fallback to uncompressed IO, otherwise we
 736                                  * will not submit these pages down to lower
 737                                  * layers.
 738                                  */
 739                                 extent_range_redirty_for_io(inode,
 740                                                 async_extent->start,
 741                                                 async_extent->start +
 742                                                 async_extent->ram_size - 1);
 743
 744                                 goto retry;
 745                         }
 746                         goto out_free;
 747                 }
 748
 749                 /*
 750                  * here we're doing allocation and writeback of the
 751                  * compressed pages
 752                  */
 753                 btrfs_drop_extent_cache(inode, async_extent->start,
 754                                         async_extent->start +
 755                                         async_extent->ram_size - 1, 0);
 756
 757                 em = alloc_extent_map();
 758                 if (!em) {
 759                         ret = -ENOMEM;
 760                         goto out_free_reserve;
 761                 }
 762                 em->start = async_extent->start;
 763                 em->len = async_extent->ram_size;
 764                 em->orig_start = em->start;
 765                 em->mod_start = em->start;
 766                 em->mod_len = em->len;
 767
 768                 em->block_start = ins.objectid;
 769                 em->block_len = ins.offset;
 770                 em->orig_block_len = ins.offset;
 771                 em->ram_bytes = async_extent->ram_size;
 772                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 773                 em->compress_type = async_extent->compress_type;
 774                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 775                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 776                 em->generation = -1;
 777
 778                 while (1) {
 779                         write_lock(&em_tree->lock);
 780                         ret = add_extent_mapping(em_tree, em, 1);
 781                         write_unlock(&em_tree->lock);
 782                         if (ret != -EEXIST) {
 783                                 free_extent_map(em);
 784                                 break;
 785                         }
 786                         btrfs_drop_extent_cache(inode, async_extent->start,
 787                                                 async_extent->start +
 788                                                 async_extent->ram_size - 1, 0);
 789                 }
 790
 791                 if (ret)
 792                         goto out_free_reserve;
 793
 794                 ret = btrfs_add_ordered_extent_compress(inode,
 795                                                 async_extent->start,
 796                                                 ins.objectid,
 797                                                 async_extent->ram_size,
 798                                                 ins.offset,
 799                                                 BTRFS_ORDERED_COMPRESSED,
 800                                                 async_extent->compress_type);
 801                 if (ret) {
 802                         btrfs_drop_extent_cache(inode, async_extent->start,
 803                                                 async_extent->start +
 804                                                 async_extent->ram_size - 1, 0);
 805                         goto out_free_reserve;
 806                 }
 807
 808                 /*
 809                  * clear dirty, set writeback and unlock the pages.
 810                  */
 811                 extent_clear_unlock_delalloc(inode, async_extent->start,
 812                                 async_extent->start +
 813                                 async_extent->ram_size - 1,
 814                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 815                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 816                                 PAGE_SET_WRITEBACK);
 817                 ret = btrfs_submit_compressed_write(inode,
 818                                     async_extent->start,
 819                                     async_extent->ram_size,
 820                                     ins.objectid,
 821                                     ins.offset, async_extent->pages,
 822                                     async_extent->nr_pages);
 823                 if (ret) {
 824                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 825                         struct page *p = async_extent->pages[0];
 826                         const u64 start = async_extent->start;
 827                         const u64 end = start + async_extent->ram_size - 1;
 828
 829                         p->mapping = inode->i_mapping;
 830                         tree->ops->writepage_end_io_hook(p, start, end,
 831                                                          NULL, 0);
 832                         p->mapping = NULL;
 833                         extent_clear_unlock_delalloc(inode, start, end, NULL, 0,
 834                                                      PAGE_END_WRITEBACK |
 835                                                      PAGE_SET_ERROR);
 836                         free_async_extent_pages(async_extent);
 837                 }
 838                 alloc_hint = ins.objectid + ins.offset;
 839                 kfree(async_extent);
 840                 cond_resched();
 841         }
 842         return;
 843 out_free_reserve:
 844         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 845 out_free:
 846         extent_clear_unlock_delalloc(inode, async_extent->start,
 847                                      async_extent->start +
 848                                      async_extent->ram_size - 1,
 849                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 850                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 851                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 852                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 853                                      PAGE_SET_ERROR);
 854         free_async_extent_pages(async_extent);
 855         kfree(async_extent);
 856         goto again;
 857 }
 858
 859 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 860                                       u64 num_bytes)
 861 {
 862         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 863         struct extent_map *em;
 864         u64 alloc_hint = 0;
 865
 866         read_lock(&em_tree->lock);
 867         em = search_extent_mapping(em_tree, start, num_bytes);
 868         if (em) {
 869                 /*
 870                  * if block start isn't an actual block number then find the
 871                  * first block in this inode and use that as a hint.  If that
 872                  * block is also bogus then just don't worry about it.
 873                  */
 874                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 875                         free_extent_map(em);
 876                         em = search_extent_mapping(em_tree, 0, 0);
 877                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 878                                 alloc_hint = em->block_start;
 879                         if (em)
 880                                 free_extent_map(em);
 881                 } else {
 882                         alloc_hint = em->block_start;
 883                         free_extent_map(em);
 884                 }
 885         }
 886         read_unlock(&em_tree->lock);
 887
 888         return alloc_hint;
 889 }
 890
 891 /*
 892  * when extent_io.c finds a delayed allocation range in the file,
 893  * the call backs end up in this code.  The basic idea is to
 894  * allocate extents on disk for the range, and create ordered data structs
 895  * in ram to track those extents.
 896  *
 897  * locked_page is the page that writepage had locked already.  We use
 898  * it to make sure we don't do extra locks or unlocks.
 899  *
 900  * *page_started is set to one if we unlock locked_page and do everything
 901  * required to start IO on it.  It may be clean and already done with
 902  * IO when we return.
 903  */
 904 static noinline int cow_file_range(struct inode *inode,
 905                                    struct page *locked_page,
 906                                    u64 start, u64 end, int *page_started,
 907                                    unsigned long *nr_written,
 908                                    int unlock)
 909 {
 910         struct btrfs_root *root = BTRFS_I(inode)->root;
 911         u64 alloc_hint = 0;
 912         u64 num_bytes;
 913         unsigned long ram_size;
 914         u64 disk_num_bytes;
 915         u64 cur_alloc_size;
 916         u64 blocksize = root->sectorsize;
 917         struct btrfs_key ins;
 918         struct extent_map *em;
 919         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 920         int ret = 0;
 921
 922         if (btrfs_is_free_space_inode(inode)) {
 923                 WARN_ON_ONCE(1);
 924                 ret = -EINVAL;
 925                 goto out_unlock;
 926         }
 927
 928         num_bytes = ALIGN(end - start + 1, blocksize);
 929         num_bytes = max(blocksize,  num_bytes);
 930         disk_num_bytes = num_bytes;
 931
 932         /* if this is a small write inside eof, kick off defrag */
 933         if (num_bytes < 64 * 1024 &&
 934             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 935                 btrfs_add_inode_defrag(NULL, inode);
 936
 937         if (start == 0) {
 938                 /* lets try to make an inline extent */
 939                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 940                                             NULL);
 941                 if (ret == 0) {
 942                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 943                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 944                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 945                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 946                                      PAGE_END_WRITEBACK);
 947
 948                         *nr_written = *nr_written +
 949                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 950                         *page_started = 1;
 951                         goto out;
 952                 } else if (ret < 0) {
 953                         goto out_unlock;
 954                 }
 955         }
 956
 957         BUG_ON(disk_num_bytes >
 958                btrfs_super_total_bytes(root->fs_info->super_copy));
 959
 960         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 961         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 962
 963         while (disk_num_bytes > 0) {
 964                 unsigned long op;
 965
 966                 cur_alloc_size = disk_num_bytes;
 967                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 968                                            root->sectorsize, 0, alloc_hint,
 969                                            &ins, 1, 1);
 970                 if (ret < 0)
 971                         goto out_unlock;
 972
 973                 em = alloc_extent_map();
 974                 if (!em) {
 975                         ret = -ENOMEM;
 976                         goto out_reserve;
 977                 }
 978                 em->start = start;
 979                 em->orig_start = em->start;
 980                 ram_size = ins.offset;
 981                 em->len = ins.offset;
 982                 em->mod_start = em->start;
 983                 em->mod_len = em->len;
 984
 985                 em->block_start = ins.objectid;
 986                 em->block_len = ins.offset;
 987                 em->orig_block_len = ins.offset;
 988                 em->ram_bytes = ram_size;
 989                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 990                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 991                 em->generation = -1;
 992
 993                 while (1) {
 994                         write_lock(&em_tree->lock);
 995                         ret = add_extent_mapping(em_tree, em, 1);
 996                         write_unlock(&em_tree->lock);
 997                         if (ret != -EEXIST) {
 998                                 free_extent_map(em);
 999                                 break;
1000                         }
1001                         btrfs_drop_extent_cache(inode, start,
1002                                                 start + ram_size - 1, 0);
1003                 }
1004                 if (ret)
1005                         goto out_reserve;
1006
1007                 cur_alloc_size = ins.offset;
1008                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1009                                                ram_size, cur_alloc_size, 0);
1010                 if (ret)
1011                         goto out_drop_extent_cache;
1012
1013                 if (root->root_key.objectid ==
1014                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1015                         ret = btrfs_reloc_clone_csums(inode, start,
1016                                                       cur_alloc_size);
1017                         if (ret)
1018                                 goto out_drop_extent_cache;
1019                 }
1020
1021                 if (disk_num_bytes < cur_alloc_size)
1022                         break;
1023
1024                 /* we're not doing compressed IO, don't unlock the first
1025                  * page (which the caller expects to stay locked), don't
1026                  * clear any dirty bits and don't set any writeback bits
1027                  *
1028                  * Do set the Private2 bit so we know this page was properly
1029                  * setup for writepage
1030                  */
1031                 op = unlock ? PAGE_UNLOCK : 0;
1032                 op |= PAGE_SET_PRIVATE2;
1033
1034                 extent_clear_unlock_delalloc(inode, start,
1035                                              start + ram_size - 1, locked_page,
1036                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1037                                              op);
1038                 disk_num_bytes -= cur_alloc_size;
1039                 num_bytes -= cur_alloc_size;
1040                 alloc_hint = ins.objectid + ins.offset;
1041                 start += cur_alloc_size;
1042         }
1043 out:
1044         return ret;
1045
1046 out_drop_extent_cache:
1047         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1048 out_reserve:
1049         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1050 out_unlock:
1051         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1052                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1053                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1054                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1055                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1056         goto out;
1057 }
1058
1059 /*
1060  * work queue call back to started compression on a file and pages
1061  */
1062 static noinline void async_cow_start(struct btrfs_work *work)
1063 {
1064         struct async_cow *async_cow;
1065         int num_added = 0;
1066         async_cow = container_of(work, struct async_cow, work);
1067
1068         compress_file_range(async_cow->inode, async_cow->locked_page,
1069                             async_cow->start, async_cow->end, async_cow,
1070                             &num_added);
1071         if (num_added == 0) {
1072                 btrfs_add_delayed_iput(async_cow->inode);
1073                 async_cow->inode = NULL;
1074         }
1075 }
1076
1077 /*
1078  * work queue call back to submit previously compressed pages
1079  */
1080 static noinline void async_cow_submit(struct btrfs_work *work)
1081 {
1082         struct async_cow *async_cow;
1083         struct btrfs_root *root;
1084         unsigned long nr_pages;
1085
1086         async_cow = container_of(work, struct async_cow, work);
1087
1088         root = async_cow->root;
1089         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1090                 PAGE_CACHE_SHIFT;
1091
1092         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1093             5 * 1024 * 1024 &&
1094             waitqueue_active(&root->fs_info->async_submit_wait))
1095                 wake_up(&root->fs_info->async_submit_wait);
1096
1097         if (async_cow->inode)
1098                 submit_compressed_extents(async_cow->inode, async_cow);
1099 }
1100
1101 static noinline void async_cow_free(struct btrfs_work *work)
1102 {
1103         struct async_cow *async_cow;
1104         async_cow = container_of(work, struct async_cow, work);
1105         if (async_cow->inode)
1106                 btrfs_add_delayed_iput(async_cow->inode);
1107         kfree(async_cow);
1108 }
1109
1110 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1111                                 u64 start, u64 end, int *page_started,
1112                                 unsigned long *nr_written)
1113 {
1114         struct async_cow *async_cow;
1115         struct btrfs_root *root = BTRFS_I(inode)->root;
1116         unsigned long nr_pages;
1117         u64 cur_end;
1118         int limit = 10 * 1024 * 1024;
1119
1120         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1121                          1, 0, NULL, GFP_NOFS);
1122         while (start < end) {
1123                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1124                 BUG_ON(!async_cow); /* -ENOMEM */
1125                 async_cow->inode = igrab(inode);
1126                 async_cow->root = root;
1127                 async_cow->locked_page = locked_page;
1128                 async_cow->start = start;
1129
1130                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1131                     !btrfs_test_opt(root, FORCE_COMPRESS))
1132                         cur_end = end;
1133                 else
1134                         cur_end = min(end, start + 512 * 1024 - 1);
1135
1136                 async_cow->end = cur_end;
1137                 INIT_LIST_HEAD(&async_cow->extents);
1138
1139                 btrfs_init_work(&async_cow->work,
1140                                 btrfs_delalloc_helper,
1141                                 async_cow_start, async_cow_submit,
1142                                 async_cow_free);
1143
1144                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1145                         PAGE_CACHE_SHIFT;
1146                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1147
1148                 btrfs_queue_work(root->fs_info->delalloc_workers,
1149                                  &async_cow->work);
1150
1151                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1152                         wait_event(root->fs_info->async_submit_wait,
1153                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1154                             limit));
1155                 }
1156
1157                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1158                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1159                         wait_event(root->fs_info->async_submit_wait,
1160                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1161                            0));
1162                 }
1163
1164                 *nr_written += nr_pages;
1165                 start = cur_end + 1;
1166         }
1167         *page_started = 1;
1168         return 0;
1169 }
1170
1171 static noinline int csum_exist_in_range(struct btrfs_root *root,
1172                                         u64 bytenr, u64 num_bytes)
1173 {
1174         int ret;
1175         struct btrfs_ordered_sum *sums;
1176         LIST_HEAD(list);
1177
1178         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1179                                        bytenr + num_bytes - 1, &list, 0);
1180         if (ret == 0 && list_empty(&list))
1181                 return 0;
1182
1183         while (!list_empty(&list)) {
1184                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1185                 list_del(&sums->list);
1186                 kfree(sums);
1187         }
1188         return 1;
1189 }
1190
1191 /*
1192  * when nowcow writeback call back.  This checks for snapshots or COW copies
1193  * of the extents that exist in the file, and COWs the file as required.
1194  *
1195  * If no cow copies or snapshots exist, we write directly to the existing
1196  * blocks on disk
1197  */
1198 static noinline int run_delalloc_nocow(struct inode *inode,
1199                                        struct page *locked_page,
1200                               u64 start, u64 end, int *page_started, int force,
1201                               unsigned long *nr_written)
1202 {
1203         struct btrfs_root *root = BTRFS_I(inode)->root;
1204         struct btrfs_trans_handle *trans;
1205         struct extent_buffer *leaf;
1206         struct btrfs_path *path;
1207         struct btrfs_file_extent_item *fi;
1208         struct btrfs_key found_key;
1209         u64 cow_start;
1210         u64 cur_offset;
1211         u64 extent_end;
1212         u64 extent_offset;
1213         u64 disk_bytenr;
1214         u64 num_bytes;
1215         u64 disk_num_bytes;
1216         u64 ram_bytes;
1217         int extent_type;
1218         int ret, err;
1219         int type;
1220         int nocow;
1221         int check_prev = 1;
1222         bool nolock;
1223         u64 ino = btrfs_ino(inode);
1224
1225         path = btrfs_alloc_path();
1226         if (!path) {
1227                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1228                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1229                                              EXTENT_DO_ACCOUNTING |
1230                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1231                                              PAGE_CLEAR_DIRTY |
1232                                              PAGE_SET_WRITEBACK |
1233                                              PAGE_END_WRITEBACK);
1234                 return -ENOMEM;
1235         }
1236
1237         nolock = btrfs_is_free_space_inode(inode);
1238
1239         if (nolock)
1240                 trans = btrfs_join_transaction_nolock(root);
1241         else
1242                 trans = btrfs_join_transaction(root);
1243
1244         if (IS_ERR(trans)) {
1245                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1246                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1247                                              EXTENT_DO_ACCOUNTING |
1248                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1249                                              PAGE_CLEAR_DIRTY |
1250                                              PAGE_SET_WRITEBACK |
1251                                              PAGE_END_WRITEBACK);
1252                 btrfs_free_path(path);
1253                 return PTR_ERR(trans);
1254         }
1255
1256         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1257
1258         cow_start = (u64)-1;
1259         cur_offset = start;
1260         while (1) {
1261                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1262                                                cur_offset, 0);
1263                 if (ret < 0)
1264                         goto error;
1265                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1266                         leaf = path->nodes[0];
1267                         btrfs_item_key_to_cpu(leaf, &found_key,
1268                                               path->slots[0] - 1);
1269                         if (found_key.objectid == ino &&
1270                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1271                                 path->slots[0]--;
1272                 }
1273                 check_prev = 0;
1274 next_slot:
1275                 leaf = path->nodes[0];
1276                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1277                         ret = btrfs_next_leaf(root, path);
1278                         if (ret < 0)
1279                                 goto error;
1280                         if (ret > 0)
1281                                 break;
1282                         leaf = path->nodes[0];
1283                 }
1284
1285                 nocow = 0;
1286                 disk_bytenr = 0;
1287                 num_bytes = 0;
1288                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1289
1290                 if (found_key.objectid > ino ||
1291                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1292                     found_key.offset > end)
1293                         break;
1294
1295                 if (found_key.offset > cur_offset) {
1296                         extent_end = found_key.offset;
1297                         extent_type = 0;
1298                         goto out_check;
1299                 }
1300
1301                 fi = btrfs_item_ptr(leaf, path->slots[0],
1302                                     struct btrfs_file_extent_item);
1303                 extent_type = btrfs_file_extent_type(leaf, fi);
1304
1305                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1306                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1307                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1308                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1309                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1310                         extent_end = found_key.offset +
1311                                 btrfs_file_extent_num_bytes(leaf, fi);
1312                         disk_num_bytes =
1313                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1314                         if (extent_end <= start) {
1315                                 path->slots[0]++;
1316                                 goto next_slot;
1317                         }
1318                         if (disk_bytenr == 0)
1319                                 goto out_check;
1320                         if (btrfs_file_extent_compression(leaf, fi) ||
1321                             btrfs_file_extent_encryption(leaf, fi) ||
1322                             btrfs_file_extent_other_encoding(leaf, fi))
1323                                 goto out_check;
1324                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1325                                 goto out_check;
1326                         if (btrfs_extent_readonly(root, disk_bytenr))
1327                                 goto out_check;
1328                         if (btrfs_cross_ref_exist(trans, root, ino,
1329                                                   found_key.offset -
1330                                                   extent_offset, disk_bytenr))
1331                                 goto out_check;
1332                         disk_bytenr += extent_offset;
1333                         disk_bytenr += cur_offset - found_key.offset;
1334                         num_bytes = min(end + 1, extent_end) - cur_offset;
1335                         /*
1336                          * if there are pending snapshots for this root,
1337                          * we fall into common COW way.
1338                          */
1339                         if (!nolock) {
1340                                 err = btrfs_start_write_no_snapshoting(root);
1341                                 if (!err)
1342                                         goto out_check;
1343                         }
1344                         /*
1345                          * force cow if csum exists in the range.
1346                          * this ensure that csum for a given extent are
1347                          * either valid or do not exist.
1348                          */
1349                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1350                                 goto out_check;
1351                         nocow = 1;
1352                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1353                         extent_end = found_key.offset +
1354                                 btrfs_file_extent_inline_len(leaf,
1355                                                      path->slots[0], fi);
1356                         extent_end = ALIGN(extent_end, root->sectorsize);
1357                 } else {
1358                         BUG_ON(1);
1359                 }
1360 out_check:
1361                 if (extent_end <= start) {
1362                         path->slots[0]++;
1363                         if (!nolock && nocow)
1364                                 btrfs_end_write_no_snapshoting(root);
1365                         goto next_slot;
1366                 }
1367                 if (!nocow) {
1368                         if (cow_start == (u64)-1)
1369                                 cow_start = cur_offset;
1370                         cur_offset = extent_end;
1371                         if (cur_offset > end)
1372                                 break;
1373                         path->slots[0]++;
1374                         goto next_slot;
1375                 }
1376
1377                 btrfs_release_path(path);
1378                 if (cow_start != (u64)-1) {
1379                         ret = cow_file_range(inode, locked_page,
1380                                              cow_start, found_key.offset - 1,
1381                                              page_started, nr_written, 1);
1382                         if (ret) {
1383                                 if (!nolock && nocow)
1384                                         btrfs_end_write_no_snapshoting(root);
1385                                 goto error;
1386                         }
1387                         cow_start = (u64)-1;
1388                 }
1389
1390                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1391                         struct extent_map *em;
1392                         struct extent_map_tree *em_tree;
1393                         em_tree = &BTRFS_I(inode)->extent_tree;
1394                         em = alloc_extent_map();
1395                         BUG_ON(!em); /* -ENOMEM */
1396                         em->start = cur_offset;
1397                         em->orig_start = found_key.offset - extent_offset;
1398                         em->len = num_bytes;
1399                         em->block_len = num_bytes;
1400                         em->block_start = disk_bytenr;
1401                         em->orig_block_len = disk_num_bytes;
1402                         em->ram_bytes = ram_bytes;
1403                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1404                         em->mod_start = em->start;
1405                         em->mod_len = em->len;
1406                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1407                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1408                         em->generation = -1;
1409                         while (1) {
1410                                 write_lock(&em_tree->lock);
1411                                 ret = add_extent_mapping(em_tree, em, 1);
1412                                 write_unlock(&em_tree->lock);
1413                                 if (ret != -EEXIST) {
1414                                         free_extent_map(em);
1415                                         break;
1416                                 }
1417                                 btrfs_drop_extent_cache(inode, em->start,
1418                                                 em->start + em->len - 1, 0);
1419                         }
1420                         type = BTRFS_ORDERED_PREALLOC;
1421                 } else {
1422                         type = BTRFS_ORDERED_NOCOW;
1423                 }
1424
1425                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1426                                                num_bytes, num_bytes, type);
1427                 BUG_ON(ret); /* -ENOMEM */
1428
1429                 if (root->root_key.objectid ==
1430                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1431                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1432                                                       num_bytes);
1433                         if (ret) {
1434                                 if (!nolock && nocow)
1435                                         btrfs_end_write_no_snapshoting(root);
1436                                 goto error;
1437                         }
1438                 }
1439
1440                 extent_clear_unlock_delalloc(inode, cur_offset,
1441                                              cur_offset + num_bytes - 1,
1442                                              locked_page, EXTENT_LOCKED |
1443                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1444                                              PAGE_SET_PRIVATE2);
1445                 if (!nolock && nocow)
1446                         btrfs_end_write_no_snapshoting(root);
1447                 cur_offset = extent_end;
1448                 if (cur_offset > end)
1449                         break;
1450         }
1451         btrfs_release_path(path);
1452
1453         if (cur_offset <= end && cow_start == (u64)-1) {
1454                 cow_start = cur_offset;
1455                 cur_offset = end;
1456         }
1457
1458         if (cow_start != (u64)-1) {
1459                 ret = cow_file_range(inode, locked_page, cow_start, end,
1460                                      page_started, nr_written, 1);
1461                 if (ret)
1462                         goto error;
1463         }
1464
1465 error:
1466         err = btrfs_end_transaction(trans, root);
1467         if (!ret)
1468                 ret = err;
1469
1470         if (ret && cur_offset < end)
1471                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1472                                              locked_page, EXTENT_LOCKED |
1473                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1474                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1475                                              PAGE_CLEAR_DIRTY |
1476                                              PAGE_SET_WRITEBACK |
1477                                              PAGE_END_WRITEBACK);
1478         btrfs_free_path(path);
1479         return ret;
1480 }
1481
1482 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1483 {
1484
1485         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1486             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1487                 return 0;
1488
1489         /*
1490          * @defrag_bytes is a hint value, no spinlock held here,
1491          * if is not zero, it means the file is defragging.
1492          * Force cow if given extent needs to be defragged.
1493          */
1494         if (BTRFS_I(inode)->defrag_bytes &&
1495             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1496                            EXTENT_DEFRAG, 0, NULL))
1497                 return 1;
1498
1499         return 0;
1500 }
1501
1502 /*
1503  * extent_io.c call back to do delayed allocation processing
1504  */
1505 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1506                               u64 start, u64 end, int *page_started,
1507                               unsigned long *nr_written)
1508 {
1509         int ret;
1510         int force_cow = need_force_cow(inode, start, end);
1511
1512         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1513                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1514                                          page_started, 1, nr_written);
1515         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1516                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1517                                          page_started, 0, nr_written);
1518         } else if (!inode_need_compress(inode)) {
1519                 ret = cow_file_range(inode, locked_page, start, end,
1520                                       page_started, nr_written, 1);
1521         } else {
1522                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1523                         &BTRFS_I(inode)->runtime_flags);
1524                 ret = cow_file_range_async(inode, locked_page, start, end,
1525                                            page_started, nr_written);
1526         }
1527         return ret;
1528 }
1529
1530 static void btrfs_split_extent_hook(struct inode *inode,
1531                                     struct extent_state *orig, u64 split)
1532 {
1533         /* not delalloc, ignore it */
1534         if (!(orig->state & EXTENT_DELALLOC))
1535                 return;
1536
1537         spin_lock(&BTRFS_I(inode)->lock);
1538         BTRFS_I(inode)->outstanding_extents++;
1539         spin_unlock(&BTRFS_I(inode)->lock);
1540 }
1541
1542 /*
1543  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1544  * extents so we can keep track of new extents that are just merged onto old
1545  * extents, such as when we are doing sequential writes, so we can properly
1546  * account for the metadata space we'll need.
1547  */
1548 static void btrfs_merge_extent_hook(struct inode *inode,
1549                                     struct extent_state *new,
1550                                     struct extent_state *other)
1551 {
1552         /* not delalloc, ignore it */
1553         if (!(other->state & EXTENT_DELALLOC))
1554                 return;
1555
1556         spin_lock(&BTRFS_I(inode)->lock);
1557         BTRFS_I(inode)->outstanding_extents--;
1558         spin_unlock(&BTRFS_I(inode)->lock);
1559 }
1560
1561 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1562                                       struct inode *inode)
1563 {
1564         spin_lock(&root->delalloc_lock);
1565         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1566                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1567                               &root->delalloc_inodes);
1568                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1569                         &BTRFS_I(inode)->runtime_flags);
1570                 root->nr_delalloc_inodes++;
1571                 if (root->nr_delalloc_inodes == 1) {
1572                         spin_lock(&root->fs_info->delalloc_root_lock);
1573                         BUG_ON(!list_empty(&root->delalloc_root));
1574                         list_add_tail(&root->delalloc_root,
1575                                       &root->fs_info->delalloc_roots);
1576                         spin_unlock(&root->fs_info->delalloc_root_lock);
1577                 }
1578         }
1579         spin_unlock(&root->delalloc_lock);
1580 }
1581
1582 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1583                                      struct inode *inode)
1584 {
1585         spin_lock(&root->delalloc_lock);
1586         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1587                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1588                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1589                           &BTRFS_I(inode)->runtime_flags);
1590                 root->nr_delalloc_inodes--;
1591                 if (!root->nr_delalloc_inodes) {
1592                         spin_lock(&root->fs_info->delalloc_root_lock);
1593                         BUG_ON(list_empty(&root->delalloc_root));
1594                         list_del_init(&root->delalloc_root);
1595                         spin_unlock(&root->fs_info->delalloc_root_lock);
1596                 }
1597         }
1598         spin_unlock(&root->delalloc_lock);
1599 }
1600
1601 /*
1602  * extent_io.c set_bit_hook, used to track delayed allocation
1603  * bytes in this file, and to maintain the list of inodes that
1604  * have pending delalloc work to be done.
1605  */
1606 static void btrfs_set_bit_hook(struct inode *inode,
1607                                struct extent_state *state, unsigned *bits)
1608 {
1609
1610         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1611                 WARN_ON(1);
1612         /*
1613          * set_bit and clear bit hooks normally require _irqsave/restore
1614          * but in this case, we are only testing for the DELALLOC
1615          * bit, which is only set or cleared with irqs on
1616          */
1617         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1618                 struct btrfs_root *root = BTRFS_I(inode)->root;
1619                 u64 len = state->end + 1 - state->start;
1620                 bool do_list = !btrfs_is_free_space_inode(inode);
1621
1622                 if (*bits & EXTENT_FIRST_DELALLOC) {
1623                         *bits &= ~EXTENT_FIRST_DELALLOC;
1624                 } else {
1625                         spin_lock(&BTRFS_I(inode)->lock);
1626                         BTRFS_I(inode)->outstanding_extents++;
1627                         spin_unlock(&BTRFS_I(inode)->lock);
1628                 }
1629
1630                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1631                                      root->fs_info->delalloc_batch);
1632                 spin_lock(&BTRFS_I(inode)->lock);
1633                 BTRFS_I(inode)->delalloc_bytes += len;
1634                 if (*bits & EXTENT_DEFRAG)
1635                         BTRFS_I(inode)->defrag_bytes += len;
1636                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1637                                          &BTRFS_I(inode)->runtime_flags))
1638                         btrfs_add_delalloc_inodes(root, inode);
1639                 spin_unlock(&BTRFS_I(inode)->lock);
1640         }
1641 }
1642
1643 /*
1644  * extent_io.c clear_bit_hook, see set_bit_hook for why
1645  */
1646 static void btrfs_clear_bit_hook(struct inode *inode,
1647                                  struct extent_state *state,
1648                                  unsigned *bits)
1649 {
1650         u64 len = state->end + 1 - state->start;
1651
1652         spin_lock(&BTRFS_I(inode)->lock);
1653         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1654                 BTRFS_I(inode)->defrag_bytes -= len;
1655         spin_unlock(&BTRFS_I(inode)->lock);
1656
1657         /*
1658          * set_bit and clear bit hooks normally require _irqsave/restore
1659          * but in this case, we are only testing for the DELALLOC
1660          * bit, which is only set or cleared with irqs on
1661          */
1662         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1663                 struct btrfs_root *root = BTRFS_I(inode)->root;
1664                 bool do_list = !btrfs_is_free_space_inode(inode);
1665
1666                 if (*bits & EXTENT_FIRST_DELALLOC) {
1667                         *bits &= ~EXTENT_FIRST_DELALLOC;
1668                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1669                         spin_lock(&BTRFS_I(inode)->lock);
1670                         BTRFS_I(inode)->outstanding_extents--;
1671                         spin_unlock(&BTRFS_I(inode)->lock);
1672                 }
1673
1674                 /*
1675                  * We don't reserve metadata space for space cache inodes so we
1676                  * don't need to call dellalloc_release_metadata if there is an
1677                  * error.
1678                  */
1679                 if (*bits & EXTENT_DO_ACCOUNTING &&
1680                     root != root->fs_info->tree_root)
1681                         btrfs_delalloc_release_metadata(inode, len);
1682
1683                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1684                     && do_list && !(state->state & EXTENT_NORESERVE))
1685                         btrfs_free_reserved_data_space(inode, len);
1686
1687                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1688                                      root->fs_info->delalloc_batch);
1689                 spin_lock(&BTRFS_I(inode)->lock);
1690                 BTRFS_I(inode)->delalloc_bytes -= len;
1691                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1692                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1693                              &BTRFS_I(inode)->runtime_flags))
1694                         btrfs_del_delalloc_inode(root, inode);
1695                 spin_unlock(&BTRFS_I(inode)->lock);
1696         }
1697 }
1698
1699 /*
1700  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1701  * we don't create bios that span stripes or chunks
1702  */
1703 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1704                          size_t size, struct bio *bio,
1705                          unsigned long bio_flags)
1706 {
1707         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1708         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1709         u64 length = 0;
1710         u64 map_length;
1711         int ret;
1712
1713         if (bio_flags & EXTENT_BIO_COMPRESSED)
1714                 return 0;
1715
1716         length = bio->bi_iter.bi_size;
1717         map_length = length;
1718         ret = btrfs_map_block(root->fs_info, rw, logical,
1719                               &map_length, NULL, 0);
1720         /* Will always return 0 with map_multi == NULL */
1721         BUG_ON(ret < 0);
1722         if (map_length < length + size)
1723                 return 1;
1724         return 0;
1725 }
1726
1727 /*
1728  * in order to insert checksums into the metadata in large chunks,
1729  * we wait until bio submission time.   All the pages in the bio are
1730  * checksummed and sums are attached onto the ordered extent record.
1731  *
1732  * At IO completion time the cums attached on the ordered extent record
1733  * are inserted into the btree
1734  */
1735 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1736                                     struct bio *bio, int mirror_num,
1737                                     unsigned long bio_flags,
1738                                     u64 bio_offset)
1739 {
1740         struct btrfs_root *root = BTRFS_I(inode)->root;
1741         int ret = 0;
1742
1743         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1744         BUG_ON(ret); /* -ENOMEM */
1745         return 0;
1746 }
1747
1748 /*
1749  * in order to insert checksums into the metadata in large chunks,
1750  * we wait until bio submission time.   All the pages in the bio are
1751  * checksummed and sums are attached onto the ordered extent record.
1752  *
1753  * At IO completion time the cums attached on the ordered extent record
1754  * are inserted into the btree
1755  */
1756 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1757                           int mirror_num, unsigned long bio_flags,
1758                           u64 bio_offset)
1759 {
1760         struct btrfs_root *root = BTRFS_I(inode)->root;
1761         int ret;
1762
1763         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1764         if (ret)
1765                 bio_endio(bio, ret);
1766         return ret;
1767 }
1768
1769 /*
1770  * extent_io.c submission hook. This does the right thing for csum calculation
1771  * on write, or reading the csums from the tree before a read
1772  */
1773 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1774                           int mirror_num, unsigned long bio_flags,
1775                           u64 bio_offset)
1776 {
1777         struct btrfs_root *root = BTRFS_I(inode)->root;
1778         int ret = 0;
1779         int skip_sum;
1780         int metadata = 0;
1781         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1782
1783         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1784
1785         if (btrfs_is_free_space_inode(inode))
1786                 metadata = 2;
1787
1788         if (!(rw & REQ_WRITE)) {
1789                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1790                 if (ret)
1791                         goto out;
1792
1793                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1794                         ret = btrfs_submit_compressed_read(inode, bio,
1795                                                            mirror_num,
1796                                                            bio_flags);
1797                         goto out;
1798                 } else if (!skip_sum) {
1799                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1800                         if (ret)
1801                                 goto out;
1802                 }
1803                 goto mapit;
1804         } else if (async && !skip_sum) {
1805                 /* csum items have already been cloned */
1806                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1807                         goto mapit;
1808                 /* we're doing a write, do the async checksumming */
1809                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1810                                    inode, rw, bio, mirror_num,
1811                                    bio_flags, bio_offset,
1812                                    __btrfs_submit_bio_start,
1813                                    __btrfs_submit_bio_done);
1814                 goto out;
1815         } else if (!skip_sum) {
1816                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1817                 if (ret)
1818                         goto out;
1819         }
1820
1821 mapit:
1822         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1823
1824 out:
1825         if (ret < 0)
1826                 bio_endio(bio, ret);
1827         return ret;
1828 }
1829
1830 /*
1831  * given a list of ordered sums record them in the inode.  This happens
1832  * at IO completion time based on sums calculated at bio submission time.
1833  */
1834 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1835                              struct inode *inode, u64 file_offset,
1836                              struct list_head *list)
1837 {
1838         struct btrfs_ordered_sum *sum;
1839
1840         list_for_each_entry(sum, list, list) {
1841                 trans->adding_csums = 1;
1842                 btrfs_csum_file_blocks(trans,
1843                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1844                 trans->adding_csums = 0;
1845         }
1846         return 0;
1847 }
1848
1849 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1850                               struct extent_state **cached_state)
1851 {
1852         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1853         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1854                                    cached_state, GFP_NOFS);
1855 }
1856
1857 /* see btrfs_writepage_start_hook for details on why this is required */
1858 struct btrfs_writepage_fixup {
1859         struct page *page;
1860         struct btrfs_work work;
1861 };
1862
1863 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1864 {
1865         struct btrfs_writepage_fixup *fixup;
1866         struct btrfs_ordered_extent *ordered;
1867         struct extent_state *cached_state = NULL;
1868         struct page *page;
1869         struct inode *inode;
1870         u64 page_start;
1871         u64 page_end;
1872         int ret;
1873
1874         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1875         page = fixup->page;
1876 again:
1877         lock_page(page);
1878         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1879                 ClearPageChecked(page);
1880                 goto out_page;
1881         }
1882
1883         inode = page->mapping->host;
1884         page_start = page_offset(page);
1885         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1886
1887         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1888                          &cached_state);
1889
1890         /* already ordered? We're done */
1891         if (PagePrivate2(page))
1892                 goto out;
1893
1894         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1895         if (ordered) {
1896                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1897                                      page_end, &cached_state, GFP_NOFS);
1898                 unlock_page(page);
1899                 btrfs_start_ordered_extent(inode, ordered, 1);
1900                 btrfs_put_ordered_extent(ordered);
1901                 goto again;
1902         }
1903
1904         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1905         if (ret) {
1906                 mapping_set_error(page->mapping, ret);
1907                 end_extent_writepage(page, ret, page_start, page_end);
1908                 ClearPageChecked(page);
1909                 goto out;
1910          }
1911
1912         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1913         ClearPageChecked(page);
1914         set_page_dirty(page);
1915 out:
1916         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1917                              &cached_state, GFP_NOFS);
1918 out_page:
1919         unlock_page(page);
1920         page_cache_release(page);
1921         kfree(fixup);
1922 }
1923
1924 /*
1925  * There are a few paths in the higher layers of the kernel that directly
1926  * set the page dirty bit without asking the filesystem if it is a
1927  * good idea.  This causes problems because we want to make sure COW
1928  * properly happens and the data=ordered rules are followed.
1929  *
1930  * In our case any range that doesn't have the ORDERED bit set
1931  * hasn't been properly setup for IO.  We kick off an async process
1932  * to fix it up.  The async helper will wait for ordered extents, set
1933  * the delalloc bit and make it safe to write the page.
1934  */
1935 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1936 {
1937         struct inode *inode = page->mapping->host;
1938         struct btrfs_writepage_fixup *fixup;
1939         struct btrfs_root *root = BTRFS_I(inode)->root;
1940
1941         /* this page is properly in the ordered list */
1942         if (TestClearPagePrivate2(page))
1943                 return 0;
1944
1945         if (PageChecked(page))
1946                 return -EAGAIN;
1947
1948         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1949         if (!fixup)
1950                 return -EAGAIN;
1951
1952         SetPageChecked(page);
1953         page_cache_get(page);
1954         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
1955                         btrfs_writepage_fixup_worker, NULL, NULL);
1956         fixup->page = page;
1957         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
1958         return -EBUSY;
1959 }
1960
1961 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1962                                        struct inode *inode, u64 file_pos,
1963                                        u64 disk_bytenr, u64 disk_num_bytes,
1964                                        u64 num_bytes, u64 ram_bytes,
1965                                        u8 compression, u8 encryption,
1966                                        u16 other_encoding, int extent_type)
1967 {
1968         struct btrfs_root *root = BTRFS_I(inode)->root;
1969         struct btrfs_file_extent_item *fi;
1970         struct btrfs_path *path;
1971         struct extent_buffer *leaf;
1972         struct btrfs_key ins;
1973         int extent_inserted = 0;
1974         int ret;
1975
1976         path = btrfs_alloc_path();
1977         if (!path)
1978                 return -ENOMEM;
1979
1980         /*
1981          * we may be replacing one extent in the tree with another.
1982          * The new extent is pinned in the extent map, and we don't want
1983          * to drop it from the cache until it is completely in the btree.
1984          *
1985          * So, tell btrfs_drop_extents to leave this extent in the cache.
1986          * the caller is expected to unpin it and allow it to be merged
1987          * with the others.
1988          */
1989         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
1990                                    file_pos + num_bytes, NULL, 0,
1991                                    1, sizeof(*fi), &extent_inserted);
1992         if (ret)
1993                 goto out;
1994
1995         if (!extent_inserted) {
1996                 ins.objectid = btrfs_ino(inode);
1997                 ins.offset = file_pos;
1998                 ins.type = BTRFS_EXTENT_DATA_KEY;
1999
2000                 path->leave_spinning = 1;
2001                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2002                                               sizeof(*fi));
2003                 if (ret)
2004                         goto out;
2005         }
2006         leaf = path->nodes[0];
2007         fi = btrfs_item_ptr(leaf, path->slots[0],
2008                             struct btrfs_file_extent_item);
2009         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2010         btrfs_set_file_extent_type(leaf, fi, extent_type);
2011         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2012         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2013         btrfs_set_file_extent_offset(leaf, fi, 0);
2014         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2015         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2016         btrfs_set_file_extent_compression(leaf, fi, compression);
2017         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2018         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2019
2020         btrfs_mark_buffer_dirty(leaf);
2021         btrfs_release_path(path);
2022
2023         inode_add_bytes(inode, num_bytes);
2024
2025         ins.objectid = disk_bytenr;
2026         ins.offset = disk_num_bytes;
2027         ins.type = BTRFS_EXTENT_ITEM_KEY;
2028         ret = btrfs_alloc_reserved_file_extent(trans, root,
2029                                         root->root_key.objectid,
2030                                         btrfs_ino(inode), file_pos, &ins);
2031 out:
2032         btrfs_free_path(path);
2033
2034         return ret;
2035 }
2036
2037 /* snapshot-aware defrag */
2038 struct sa_defrag_extent_backref {
2039         struct rb_node node;
2040         struct old_sa_defrag_extent *old;
2041         u64 root_id;
2042         u64 inum;
2043         u64 file_pos;
2044         u64 extent_offset;
2045         u64 num_bytes;
2046         u64 generation;
2047 };
2048
2049 struct old_sa_defrag_extent {
2050         struct list_head list;
2051         struct new_sa_defrag_extent *new;
2052
2053         u64 extent_offset;
2054         u64 bytenr;
2055         u64 offset;
2056         u64 len;
2057         int count;
2058 };
2059
2060 struct new_sa_defrag_extent {
2061         struct rb_root root;
2062         struct list_head head;
2063         struct btrfs_path *path;
2064         struct inode *inode;
2065         u64 file_pos;
2066         u64 len;
2067         u64 bytenr;
2068         u64 disk_len;
2069         u8 compress_type;
2070 };
2071
2072 static int backref_comp(struct sa_defrag_extent_backref *b1,
2073                         struct sa_defrag_extent_backref *b2)
2074 {
2075         if (b1->root_id < b2->root_id)
2076                 return -1;
2077         else if (b1->root_id > b2->root_id)
2078                 return 1;
2079
2080         if (b1->inum < b2->inum)
2081                 return -1;
2082         else if (b1->inum > b2->inum)
2083                 return 1;
2084
2085         if (b1->file_pos < b2->file_pos)
2086                 return -1;
2087         else if (b1->file_pos > b2->file_pos)
2088                 return 1;
2089
2090         /*
2091          * [------------------------------] ===> (a range of space)
2092          *     |<--->|   |<---->| =============> (fs/file tree A)
2093          * |<---------------------------->| ===> (fs/file tree B)
2094          *
2095          * A range of space can refer to two file extents in one tree while
2096          * refer to only one file extent in another tree.
2097          *
2098          * So we may process a disk offset more than one time(two extents in A)
2099          * and locate at the same extent(one extent in B), then insert two same
2100          * backrefs(both refer to the extent in B).
2101          */
2102         return 0;
2103 }
2104
2105 static void backref_insert(struct rb_root *root,
2106                            struct sa_defrag_extent_backref *backref)
2107 {
2108         struct rb_node **p = &root->rb_node;
2109         struct rb_node *parent = NULL;
2110         struct sa_defrag_extent_backref *entry;
2111         int ret;
2112
2113         while (*p) {
2114                 parent = *p;
2115                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2116
2117                 ret = backref_comp(backref, entry);
2118                 if (ret < 0)
2119                         p = &(*p)->rb_left;
2120                 else
2121                         p = &(*p)->rb_right;
2122         }
2123
2124         rb_link_node(&backref->node, parent, p);
2125         rb_insert_color(&backref->node, root);
2126 }
2127
2128 /*
2129  * Note the backref might has changed, and in this case we just return 0.
2130  */
2131 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2132                                        void *ctx)
2133 {
2134         struct btrfs_file_extent_item *extent;
2135         struct btrfs_fs_info *fs_info;
2136         struct old_sa_defrag_extent *old = ctx;
2137         struct new_sa_defrag_extent *new = old->new;
2138         struct btrfs_path *path = new->path;
2139         struct btrfs_key key;
2140         struct btrfs_root *root;
2141         struct sa_defrag_extent_backref *backref;
2142         struct extent_buffer *leaf;
2143         struct inode *inode = new->inode;
2144         int slot;
2145         int ret;
2146         u64 extent_offset;
2147         u64 num_bytes;
2148
2149         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2150             inum == btrfs_ino(inode))
2151                 return 0;
2152
2153         key.objectid = root_id;
2154         key.type = BTRFS_ROOT_ITEM_KEY;
2155         key.offset = (u64)-1;
2156
2157         fs_info = BTRFS_I(inode)->root->fs_info;
2158         root = btrfs_read_fs_root_no_name(fs_info, &key);
2159         if (IS_ERR(root)) {
2160                 if (PTR_ERR(root) == -ENOENT)
2161                         return 0;
2162                 WARN_ON(1);
2163                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2164                          inum, offset, root_id);
2165                 return PTR_ERR(root);
2166         }
2167
2168         key.objectid = inum;
2169         key.type = BTRFS_EXTENT_DATA_KEY;
2170         if (offset > (u64)-1 << 32)
2171                 key.offset = 0;
2172         else
2173                 key.offset = offset;
2174
2175         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2176         if (WARN_ON(ret < 0))
2177                 return ret;
2178         ret = 0;
2179
2180         while (1) {
2181                 cond_resched();
2182
2183                 leaf = path->nodes[0];
2184                 slot = path->slots[0];
2185
2186                 if (slot >= btrfs_header_nritems(leaf)) {
2187                         ret = btrfs_next_leaf(root, path);
2188                         if (ret < 0) {
2189                                 goto out;
2190                         } else if (ret > 0) {
2191                                 ret = 0;
2192                                 goto out;
2193                         }
2194                         continue;
2195                 }
2196
2197                 path->slots[0]++;
2198
2199                 btrfs_item_key_to_cpu(leaf, &key, slot);
2200
2201                 if (key.objectid > inum)
2202                         goto out;
2203
2204                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2205                         continue;
2206
2207                 extent = btrfs_item_ptr(leaf, slot,
2208                                         struct btrfs_file_extent_item);
2209
2210                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2211                         continue;
2212
2213                 /*
2214                  * 'offset' refers to the exact key.offset,
2215                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2216                  * (key.offset - extent_offset).
2217                  */
2218                 if (key.offset != offset)
2219                         continue;
2220
2221                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2222                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2223
2224                 if (extent_offset >= old->extent_offset + old->offset +
2225                     old->len || extent_offset + num_bytes <=
2226                     old->extent_offset + old->offset)
2227                         continue;
2228                 break;
2229         }
2230
2231         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2232         if (!backref) {
2233                 ret = -ENOENT;
2234                 goto out;
2235         }
2236
2237         backref->root_id = root_id;
2238         backref->inum = inum;
2239         backref->file_pos = offset;
2240         backref->num_bytes = num_bytes;
2241         backref->extent_offset = extent_offset;
2242         backref->generation = btrfs_file_extent_generation(leaf, extent);
2243         backref->old = old;
2244         backref_insert(&new->root, backref);
2245         old->count++;
2246 out:
2247         btrfs_release_path(path);
2248         WARN_ON(ret);
2249         return ret;
2250 }
2251
2252 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2253                                    struct new_sa_defrag_extent *new)
2254 {
2255         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2256         struct old_sa_defrag_extent *old, *tmp;
2257         int ret;
2258
2259         new->path = path;
2260
2261         list_for_each_entry_safe(old, tmp, &new->head, list) {
2262                 ret = iterate_inodes_from_logical(old->bytenr +
2263                                                   old->extent_offset, fs_info,
2264                                                   path, record_one_backref,
2265                                                   old);
2266                 if (ret < 0 && ret != -ENOENT)
2267                         return false;
2268
2269                 /* no backref to be processed for this extent */
2270                 if (!old->count) {
2271                         list_del(&old->list);
2272                         kfree(old);
2273                 }
2274         }
2275
2276         if (list_empty(&new->head))
2277                 return false;
2278
2279         return true;
2280 }
2281
2282 static int relink_is_mergable(struct extent_buffer *leaf,
2283                               struct btrfs_file_extent_item *fi,
2284                               struct new_sa_defrag_extent *new)
2285 {
2286         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2287                 return 0;
2288
2289         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2290                 return 0;
2291
2292         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2293                 return 0;
2294
2295         if (btrfs_file_extent_encryption(leaf, fi) ||
2296             btrfs_file_extent_other_encoding(leaf, fi))
2297                 return 0;
2298
2299         return 1;
2300 }
2301
2302 /*
2303  * Note the backref might has changed, and in this case we just return 0.
2304  */
2305 static noinline int relink_extent_backref(struct btrfs_path *path,
2306                                  struct sa_defrag_extent_backref *prev,
2307                                  struct sa_defrag_extent_backref *backref)
2308 {
2309         struct btrfs_file_extent_item *extent;
2310         struct btrfs_file_extent_item *item;
2311         struct btrfs_ordered_extent *ordered;
2312         struct btrfs_trans_handle *trans;
2313         struct btrfs_fs_info *fs_info;
2314         struct btrfs_root *root;
2315         struct btrfs_key key;
2316         struct extent_buffer *leaf;
2317         struct old_sa_defrag_extent *old = backref->old;
2318         struct new_sa_defrag_extent *new = old->new;
2319         struct inode *src_inode = new->inode;
2320         struct inode *inode;
2321         struct extent_state *cached = NULL;
2322         int ret = 0;
2323         u64 start;
2324         u64 len;
2325         u64 lock_start;
2326         u64 lock_end;
2327         bool merge = false;
2328         int index;
2329
2330         if (prev && prev->root_id == backref->root_id &&
2331             prev->inum == backref->inum &&
2332             prev->file_pos + prev->num_bytes == backref->file_pos)
2333                 merge = true;
2334
2335         /* step 1: get root */
2336         key.objectid = backref->root_id;
2337         key.type = BTRFS_ROOT_ITEM_KEY;
2338         key.offset = (u64)-1;
2339
2340         fs_info = BTRFS_I(src_inode)->root->fs_info;
2341         index = srcu_read_lock(&fs_info->subvol_srcu);
2342
2343         root = btrfs_read_fs_root_no_name(fs_info, &key);
2344         if (IS_ERR(root)) {
2345                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2346                 if (PTR_ERR(root) == -ENOENT)
2347                         return 0;
2348                 return PTR_ERR(root);
2349         }
2350
2351         if (btrfs_root_readonly(root)) {
2352                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2353                 return 0;
2354         }
2355
2356         /* step 2: get inode */
2357         key.objectid = backref->inum;
2358         key.type = BTRFS_INODE_ITEM_KEY;
2359         key.offset = 0;
2360
2361         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2362         if (IS_ERR(inode)) {
2363                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2364                 return 0;
2365         }
2366
2367         srcu_read_unlock(&fs_info->subvol_srcu, index);
2368
2369         /* step 3: relink backref */
2370         lock_start = backref->file_pos;
2371         lock_end = backref->file_pos + backref->num_bytes - 1;
2372         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2373                          0, &cached);
2374
2375         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2376         if (ordered) {
2377                 btrfs_put_ordered_extent(ordered);
2378                 goto out_unlock;
2379         }
2380
2381         trans = btrfs_join_transaction(root);
2382         if (IS_ERR(trans)) {
2383                 ret = PTR_ERR(trans);
2384                 goto out_unlock;
2385         }
2386
2387         key.objectid = backref->inum;
2388         key.type = BTRFS_EXTENT_DATA_KEY;
2389         key.offset = backref->file_pos;
2390
2391         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2392         if (ret < 0) {
2393                 goto out_free_path;
2394         } else if (ret > 0) {
2395                 ret = 0;
2396                 goto out_free_path;
2397         }
2398
2399         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2400                                 struct btrfs_file_extent_item);
2401
2402         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2403             backref->generation)
2404                 goto out_free_path;
2405
2406         btrfs_release_path(path);
2407
2408         start = backref->file_pos;
2409         if (backref->extent_offset < old->extent_offset + old->offset)
2410                 start += old->extent_offset + old->offset -
2411                          backref->extent_offset;
2412
2413         len = min(backref->extent_offset + backref->num_bytes,
2414                   old->extent_offset + old->offset + old->len);
2415         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2416
2417         ret = btrfs_drop_extents(trans, root, inode, start,
2418                                  start + len, 1);
2419         if (ret)
2420                 goto out_free_path;
2421 again:
2422         key.objectid = btrfs_ino(inode);
2423         key.type = BTRFS_EXTENT_DATA_KEY;
2424         key.offset = start;
2425
2426         path->leave_spinning = 1;
2427         if (merge) {
2428                 struct btrfs_file_extent_item *fi;
2429                 u64 extent_len;
2430                 struct btrfs_key found_key;
2431
2432                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2433                 if (ret < 0)
2434                         goto out_free_path;
2435
2436                 path->slots[0]--;
2437                 leaf = path->nodes[0];
2438                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2439
2440                 fi = btrfs_item_ptr(leaf, path->slots[0],
2441                                     struct btrfs_file_extent_item);
2442                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2443
2444                 if (extent_len + found_key.offset == start &&
2445                     relink_is_mergable(leaf, fi, new)) {
2446                         btrfs_set_file_extent_num_bytes(leaf, fi,
2447                                                         extent_len + len);
2448                         btrfs_mark_buffer_dirty(leaf);
2449                         inode_add_bytes(inode, len);
2450
2451                         ret = 1;
2452                         goto out_free_path;
2453                 } else {
2454                         merge = false;
2455                         btrfs_release_path(path);
2456                         goto again;
2457                 }
2458         }
2459
2460         ret = btrfs_insert_empty_item(trans, root, path, &key,
2461                                         sizeof(*extent));
2462         if (ret) {
2463                 btrfs_abort_transaction(trans, root, ret);
2464                 goto out_free_path;
2465         }
2466
2467         leaf = path->nodes[0];
2468         item = btrfs_item_ptr(leaf, path->slots[0],
2469                                 struct btrfs_file_extent_item);
2470         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2471         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2472         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2473         btrfs_set_file_extent_num_bytes(leaf, item, len);
2474         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2475         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2476         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2477         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2478         btrfs_set_file_extent_encryption(leaf, item, 0);
2479         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2480
2481         btrfs_mark_buffer_dirty(leaf);
2482         inode_add_bytes(inode, len);
2483         btrfs_release_path(path);
2484
2485         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2486                         new->disk_len, 0,
2487                         backref->root_id, backref->inum,
2488                         new->file_pos, 0);      /* start - extent_offset */
2489         if (ret) {
2490                 btrfs_abort_transaction(trans, root, ret);
2491                 goto out_free_path;
2492         }
2493
2494         ret = 1;
2495 out_free_path:
2496         btrfs_release_path(path);
2497         path->leave_spinning = 0;
2498         btrfs_end_transaction(trans, root);
2499 out_unlock:
2500         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2501                              &cached, GFP_NOFS);
2502         iput(inode);
2503         return ret;
2504 }
2505
2506 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2507 {
2508         struct old_sa_defrag_extent *old, *tmp;
2509
2510         if (!new)
2511                 return;
2512
2513         list_for_each_entry_safe(old, tmp, &new->head, list) {
2514                 list_del(&old->list);
2515                 kfree(old);
2516         }
2517         kfree(new);
2518 }
2519
2520 static void relink_file_extents(struct new_sa_defrag_extent *new)
2521 {
2522         struct btrfs_path *path;
2523         struct sa_defrag_extent_backref *backref;
2524         struct sa_defrag_extent_backref *prev = NULL;
2525         struct inode *inode;
2526         struct btrfs_root *root;
2527         struct rb_node *node;
2528         int ret;
2529
2530         inode = new->inode;
2531         root = BTRFS_I(inode)->root;
2532
2533         path = btrfs_alloc_path();
2534         if (!path)
2535                 return;
2536
2537         if (!record_extent_backrefs(path, new)) {
2538                 btrfs_free_path(path);
2539                 goto out;
2540         }
2541         btrfs_release_path(path);
2542
2543         while (1) {
2544                 node = rb_first(&new->root);
2545                 if (!node)
2546                         break;
2547                 rb_erase(node, &new->root);
2548
2549                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2550
2551                 ret = relink_extent_backref(path, prev, backref);
2552                 WARN_ON(ret < 0);
2553
2554                 kfree(prev);
2555
2556                 if (ret == 1)
2557                         prev = backref;
2558                 else
2559                         prev = NULL;
2560                 cond_resched();
2561         }
2562         kfree(prev);
2563
2564         btrfs_free_path(path);
2565 out:
2566         free_sa_defrag_extent(new);
2567
2568         atomic_dec(&root->fs_info->defrag_running);
2569         wake_up(&root->fs_info->transaction_wait);
2570 }
2571
2572 static struct new_sa_defrag_extent *
2573 record_old_file_extents(struct inode *inode,
2574                         struct btrfs_ordered_extent *ordered)
2575 {
2576         struct btrfs_root *root = BTRFS_I(inode)->root;
2577         struct btrfs_path *path;
2578         struct btrfs_key key;
2579         struct old_sa_defrag_extent *old;
2580         struct new_sa_defrag_extent *new;
2581         int ret;
2582
2583         new = kmalloc(sizeof(*new), GFP_NOFS);
2584         if (!new)
2585                 return NULL;
2586
2587         new->inode = inode;
2588         new->file_pos = ordered->file_offset;
2589         new->len = ordered->len;
2590         new->bytenr = ordered->start;
2591         new->disk_len = ordered->disk_len;
2592         new->compress_type = ordered->compress_type;
2593         new->root = RB_ROOT;
2594         INIT_LIST_HEAD(&new->head);
2595
2596         path = btrfs_alloc_path();
2597         if (!path)
2598                 goto out_kfree;
2599
2600         key.objectid = btrfs_ino(inode);
2601         key.type = BTRFS_EXTENT_DATA_KEY;
2602         key.offset = new->file_pos;
2603
2604         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2605         if (ret < 0)
2606                 goto out_free_path;
2607         if (ret > 0 && path->slots[0] > 0)
2608                 path->slots[0]--;
2609
2610         /* find out all the old extents for the file range */
2611         while (1) {
2612                 struct btrfs_file_extent_item *extent;
2613                 struct extent_buffer *l;
2614                 int slot;
2615                 u64 num_bytes;
2616                 u64 offset;
2617                 u64 end;
2618                 u64 disk_bytenr;
2619                 u64 extent_offset;
2620
2621                 l = path->nodes[0];
2622                 slot = path->slots[0];
2623
2624                 if (slot >= btrfs_header_nritems(l)) {
2625                         ret = btrfs_next_leaf(root, path);
2626                         if (ret < 0)
2627                                 goto out_free_path;
2628                         else if (ret > 0)
2629                                 break;
2630                         continue;
2631                 }
2632
2633                 btrfs_item_key_to_cpu(l, &key, slot);
2634
2635                 if (key.objectid != btrfs_ino(inode))
2636                         break;
2637                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2638                         break;
2639                 if (key.offset >= new->file_pos + new->len)
2640                         break;
2641
2642                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2643
2644                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2645                 if (key.offset + num_bytes < new->file_pos)
2646                         goto next;
2647
2648                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2649                 if (!disk_bytenr)
2650                         goto next;
2651
2652                 extent_offset = btrfs_file_extent_offset(l, extent);
2653
2654                 old = kmalloc(sizeof(*old), GFP_NOFS);
2655                 if (!old)
2656                         goto out_free_path;
2657
2658                 offset = max(new->file_pos, key.offset);
2659                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2660
2661                 old->bytenr = disk_bytenr;
2662                 old->extent_offset = extent_offset;
2663                 old->offset = offset - key.offset;
2664                 old->len = end - offset;
2665                 old->new = new;
2666                 old->count = 0;
2667                 list_add_tail(&old->list, &new->head);
2668 next:
2669                 path->slots[0]++;
2670                 cond_resched();
2671         }
2672
2673         btrfs_free_path(path);
2674         atomic_inc(&root->fs_info->defrag_running);
2675
2676         return new;
2677
2678 out_free_path:
2679         btrfs_free_path(path);
2680 out_kfree:
2681         free_sa_defrag_extent(new);
2682         return NULL;
2683 }
2684
2685 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2686                                          u64 start, u64 len)
2687 {
2688         struct btrfs_block_group_cache *cache;
2689
2690         cache = btrfs_lookup_block_group(root->fs_info, start);
2691         ASSERT(cache);
2692
2693         spin_lock(&cache->lock);
2694         cache->delalloc_bytes -= len;
2695         spin_unlock(&cache->lock);
2696
2697         btrfs_put_block_group(cache);
2698 }
2699
2700 /* as ordered data IO finishes, this gets called so we can finish
2701  * an ordered extent if the range of bytes in the file it covers are
2702  * fully written.
2703  */
2704 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2705 {
2706         struct inode *inode = ordered_extent->inode;
2707         struct btrfs_root *root = BTRFS_I(inode)->root;
2708         struct btrfs_trans_handle *trans = NULL;
2709         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2710         struct extent_state *cached_state = NULL;
2711         struct new_sa_defrag_extent *new = NULL;
2712         int compress_type = 0;
2713         int ret = 0;
2714         u64 logical_len = ordered_extent->len;
2715         bool nolock;
2716         bool truncated = false;
2717
2718         nolock = btrfs_is_free_space_inode(inode);
2719
2720         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2721                 ret = -EIO;
2722                 goto out;
2723         }
2724
2725         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2726                                      ordered_extent->file_offset +
2727                                      ordered_extent->len - 1);
2728
2729         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2730                 truncated = true;
2731                 logical_len = ordered_extent->truncated_len;
2732                 /* Truncated the entire extent, don't bother adding */
2733                 if (!logical_len)
2734                         goto out;
2735         }
2736
2737         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2738                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2739                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2740                 if (nolock)
2741                         trans = btrfs_join_transaction_nolock(root);
2742                 else
2743                         trans = btrfs_join_transaction(root);
2744                 if (IS_ERR(trans)) {
2745                         ret = PTR_ERR(trans);
2746                         trans = NULL;
2747                         goto out;
2748                 }
2749                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2750                 ret = btrfs_update_inode_fallback(trans, root, inode);
2751                 if (ret) /* -ENOMEM or corruption */
2752                         btrfs_abort_transaction(trans, root, ret);
2753                 goto out;
2754         }
2755
2756         lock_extent_bits(io_tree, ordered_extent->file_offset,
2757                          ordered_extent->file_offset + ordered_extent->len - 1,
2758                          0, &cached_state);
2759
2760         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2761                         ordered_extent->file_offset + ordered_extent->len - 1,
2762                         EXTENT_DEFRAG, 1, cached_state);
2763         if (ret) {
2764                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2765                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2766                         /* the inode is shared */
2767                         new = record_old_file_extents(inode, ordered_extent);
2768
2769                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2770                         ordered_extent->file_offset + ordered_extent->len - 1,
2771                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2772         }
2773
2774         if (nolock)
2775                 trans = btrfs_join_transaction_nolock(root);
2776         else
2777                 trans = btrfs_join_transaction(root);
2778         if (IS_ERR(trans)) {
2779                 ret = PTR_ERR(trans);
2780                 trans = NULL;
2781                 goto out_unlock;
2782         }
2783
2784         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2785
2786         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2787                 compress_type = ordered_extent->compress_type;
2788         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2789                 BUG_ON(compress_type);
2790                 ret = btrfs_mark_extent_written(trans, inode,
2791                                                 ordered_extent->file_offset,
2792                                                 ordered_extent->file_offset +
2793                                                 logical_len);
2794         } else {
2795                 BUG_ON(root == root->fs_info->tree_root);
2796                 ret = insert_reserved_file_extent(trans, inode,
2797                                                 ordered_extent->file_offset,
2798                                                 ordered_extent->start,
2799                                                 ordered_extent->disk_len,
2800                                                 logical_len, logical_len,
2801                                                 compress_type, 0, 0,
2802                                                 BTRFS_FILE_EXTENT_REG);
2803                 if (!ret)
2804                         btrfs_release_delalloc_bytes(root,
2805                                                      ordered_extent->start,
2806                                                      ordered_extent->disk_len);
2807         }
2808         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2809                            ordered_extent->file_offset, ordered_extent->len,
2810                            trans->transid);
2811         if (ret < 0) {
2812                 btrfs_abort_transaction(trans, root, ret);
2813                 goto out_unlock;
2814         }
2815
2816         add_pending_csums(trans, inode, ordered_extent->file_offset,
2817                           &ordered_extent->list);
2818
2819         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2820         ret = btrfs_update_inode_fallback(trans, root, inode);
2821         if (ret) { /* -ENOMEM or corruption */
2822                 btrfs_abort_transaction(trans, root, ret);
2823                 goto out_unlock;
2824         }
2825         ret = 0;
2826 out_unlock:
2827         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2828                              ordered_extent->file_offset +
2829                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2830 out:
2831         if (root != root->fs_info->tree_root)
2832                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2833         if (trans)
2834                 btrfs_end_transaction(trans, root);
2835
2836         if (ret || truncated) {
2837                 u64 start, end;
2838
2839                 if (truncated)
2840                         start = ordered_extent->file_offset + logical_len;
2841                 else
2842                         start = ordered_extent->file_offset;
2843                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2844                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2845
2846                 /* Drop the cache for the part of the extent we didn't write. */
2847                 btrfs_drop_extent_cache(inode, start, end, 0);
2848
2849                 /*
2850                  * If the ordered extent had an IOERR or something else went
2851                  * wrong we need to return the space for this ordered extent
2852                  * back to the allocator.  We only free the extent in the
2853                  * truncated case if we didn't write out the extent at all.
2854                  */
2855                 if ((ret || !logical_len) &&
2856                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2857                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2858                         btrfs_free_reserved_extent(root, ordered_extent->start,
2859                                                    ordered_extent->disk_len, 1);
2860         }
2861
2862
2863         /*
2864          * This needs to be done to make sure anybody waiting knows we are done
2865          * updating everything for this ordered extent.
2866          */
2867         btrfs_remove_ordered_extent(inode, ordered_extent);
2868
2869         /* for snapshot-aware defrag */
2870         if (new) {
2871                 if (ret) {
2872                         free_sa_defrag_extent(new);
2873                         atomic_dec(&root->fs_info->defrag_running);
2874                 } else {
2875                         relink_file_extents(new);
2876                 }
2877         }
2878
2879         /* once for us */
2880         btrfs_put_ordered_extent(ordered_extent);
2881         /* once for the tree */
2882         btrfs_put_ordered_extent(ordered_extent);
2883
2884         return ret;
2885 }
2886
2887 static void finish_ordered_fn(struct btrfs_work *work)
2888 {
2889         struct btrfs_ordered_extent *ordered_extent;
2890         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2891         btrfs_finish_ordered_io(ordered_extent);
2892 }
2893
2894 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2895                                 struct extent_state *state, int uptodate)
2896 {
2897         struct inode *inode = page->mapping->host;
2898         struct btrfs_root *root = BTRFS_I(inode)->root;
2899         struct btrfs_ordered_extent *ordered_extent = NULL;
2900         struct btrfs_workqueue *wq;
2901         btrfs_work_func_t func;
2902
2903         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2904
2905         ClearPagePrivate2(page);
2906         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2907                                             end - start + 1, uptodate))
2908                 return 0;
2909
2910         if (btrfs_is_free_space_inode(inode)) {
2911                 wq = root->fs_info->endio_freespace_worker;
2912                 func = btrfs_freespace_write_helper;
2913         } else {
2914                 wq = root->fs_info->endio_write_workers;
2915                 func = btrfs_endio_write_helper;
2916         }
2917
2918         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
2919                         NULL);
2920         btrfs_queue_work(wq, &ordered_extent->work);
2921
2922         return 0;
2923 }
2924
2925 static int __readpage_endio_check(struct inode *inode,
2926                                   struct btrfs_io_bio *io_bio,
2927                                   int icsum, struct page *page,
2928                                   int pgoff, u64 start, size_t len)
2929 {
2930         char *kaddr;
2931         u32 csum_expected;
2932         u32 csum = ~(u32)0;
2933         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2934                                       DEFAULT_RATELIMIT_BURST);
2935
2936         csum_expected = *(((u32 *)io_bio->csum) + icsum);
2937
2938         kaddr = kmap_atomic(page);
2939         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
2940         btrfs_csum_final(csum, (char *)&csum);
2941         if (csum != csum_expected)
2942                 goto zeroit;
2943
2944         kunmap_atomic(kaddr);
2945         return 0;
2946 zeroit:
2947         if (__ratelimit(&_rs))
2948                 btrfs_warn(BTRFS_I(inode)->root->fs_info,
2949                            "csum failed ino %llu off %llu csum %u expected csum %u",
2950                            btrfs_ino(inode), start, csum, csum_expected);
2951         memset(kaddr + pgoff, 1, len);
2952         flush_dcache_page(page);
2953         kunmap_atomic(kaddr);
2954         if (csum_expected == 0)
2955                 return 0;
2956         return -EIO;
2957 }
2958
2959 /*
2960  * when reads are done, we need to check csums to verify the data is correct
2961  * if there's a match, we allow the bio to finish.  If not, the code in
2962  * extent_io.c will try to find good copies for us.
2963  */
2964 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2965                                       u64 phy_offset, struct page *page,
2966                                       u64 start, u64 end, int mirror)
2967 {
2968         size_t offset = start - page_offset(page);
2969         struct inode *inode = page->mapping->host;
2970         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2971         struct btrfs_root *root = BTRFS_I(inode)->root;
2972
2973         if (PageChecked(page)) {
2974                 ClearPageChecked(page);
2975                 return 0;
2976         }
2977
2978         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2979                 return 0;
2980
2981         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2982             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2983                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2984                                   GFP_NOFS);
2985                 return 0;
2986         }
2987
2988         phy_offset >>= inode->i_sb->s_blocksize_bits;
2989         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
2990                                       start, (size_t)(end - start + 1));
2991 }
2992
2993 struct delayed_iput {
2994         struct list_head list;
2995         struct inode *inode;
2996 };
2997
2998 /* JDM: If this is fs-wide, why can't we add a pointer to
2999  * btrfs_inode instead and avoid the allocation? */
3000 void btrfs_add_delayed_iput(struct inode *inode)
3001 {
3002         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3003         struct delayed_iput *delayed;
3004
3005         if (atomic_add_unless(&inode->i_count, -1, 1))
3006                 return;
3007
3008         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
3009         delayed->inode = inode;
3010
3011         spin_lock(&fs_info->delayed_iput_lock);
3012         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
3013         spin_unlock(&fs_info->delayed_iput_lock);
3014 }
3015
3016 void btrfs_run_delayed_iputs(struct btrfs_root *root)
3017 {
3018         LIST_HEAD(list);
3019         struct btrfs_fs_info *fs_info = root->fs_info;
3020         struct delayed_iput *delayed;
3021         int empty;
3022
3023         spin_lock(&fs_info->delayed_iput_lock);
3024         empty = list_empty(&fs_info->delayed_iputs);
3025         spin_unlock(&fs_info->delayed_iput_lock);
3026         if (empty)
3027                 return;
3028
3029         spin_lock(&fs_info->delayed_iput_lock);
3030         list_splice_init(&fs_info->delayed_iputs, &list);
3031         spin_unlock(&fs_info->delayed_iput_lock);
3032
3033         while (!list_empty(&list)) {
3034                 delayed = list_entry(list.next, struct delayed_iput, list);
3035                 list_del(&delayed->list);
3036                 iput(delayed->inode);
3037                 kfree(delayed);
3038         }
3039 }
3040
3041 /*
3042  * This is called in transaction commit time. If there are no orphan
3043  * files in the subvolume, it removes orphan item and frees block_rsv
3044  * structure.
3045  */
3046 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3047                               struct btrfs_root *root)
3048 {
3049         struct btrfs_block_rsv *block_rsv;
3050         int ret;
3051
3052         if (atomic_read(&root->orphan_inodes) ||
3053             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3054                 return;
3055
3056         spin_lock(&root->orphan_lock);
3057         if (atomic_read(&root->orphan_inodes)) {
3058                 spin_unlock(&root->orphan_lock);
3059                 return;
3060         }
3061
3062         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3063                 spin_unlock(&root->orphan_lock);
3064                 return;
3065         }
3066
3067         block_rsv = root->orphan_block_rsv;
3068         root->orphan_block_rsv = NULL;
3069         spin_unlock(&root->orphan_lock);
3070
3071         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3072             btrfs_root_refs(&root->root_item) > 0) {
3073                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
3074                                             root->root_key.objectid);
3075                 if (ret)
3076                         btrfs_abort_transaction(trans, root, ret);
3077                 else
3078                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3079                                   &root->state);
3080         }
3081
3082         if (block_rsv) {
3083                 WARN_ON(block_rsv->size > 0);
3084                 btrfs_free_block_rsv(root, block_rsv);
3085         }
3086 }
3087
3088 /*
3089  * This creates an orphan entry for the given inode in case something goes
3090  * wrong in the middle of an unlink/truncate.
3091  *
3092  * NOTE: caller of this function should reserve 5 units of metadata for
3093  *       this function.
3094  */
3095 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3096 {
3097         struct btrfs_root *root = BTRFS_I(inode)->root;
3098         struct btrfs_block_rsv *block_rsv = NULL;
3099         int reserve = 0;
3100         int insert = 0;
3101         int ret;
3102
3103         if (!root->orphan_block_rsv) {
3104                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3105                 if (!block_rsv)
3106                         return -ENOMEM;
3107         }
3108
3109         spin_lock(&root->orphan_lock);
3110         if (!root->orphan_block_rsv) {
3111                 root->orphan_block_rsv = block_rsv;
3112         } else if (block_rsv) {
3113                 btrfs_free_block_rsv(root, block_rsv);
3114                 block_rsv = NULL;
3115         }
3116
3117         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3118                               &BTRFS_I(inode)->runtime_flags)) {
3119 #if 0
3120                 /*
3121                  * For proper ENOSPC handling, we should do orphan
3122                  * cleanup when mounting. But this introduces backward
3123                  * compatibility issue.
3124                  */
3125                 if (!xchg(&root->orphan_item_inserted, 1))
3126                         insert = 2;
3127                 else
3128                         insert = 1;
3129 #endif
3130                 insert = 1;
3131                 atomic_inc(&root->orphan_inodes);
3132         }
3133
3134         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3135                               &BTRFS_I(inode)->runtime_flags))
3136                 reserve = 1;
3137         spin_unlock(&root->orphan_lock);
3138
3139         /* grab metadata reservation from transaction handle */
3140         if (reserve) {
3141                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3142                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3143         }
3144
3145         /* insert an orphan item to track this unlinked/truncated file */
3146         if (insert >= 1) {
3147                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3148                 if (ret) {
3149                         atomic_dec(&root->orphan_inodes);
3150                         if (reserve) {
3151                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3152                                           &BTRFS_I(inode)->runtime_flags);
3153                                 btrfs_orphan_release_metadata(inode);
3154                         }
3155                         if (ret != -EEXIST) {
3156                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3157                                           &BTRFS_I(inode)->runtime_flags);
3158                                 btrfs_abort_transaction(trans, root, ret);
3159                                 return ret;
3160                         }
3161                 }
3162                 ret = 0;
3163         }
3164
3165         /* insert an orphan item to track subvolume contains orphan files */
3166         if (insert >= 2) {
3167                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3168                                                root->root_key.objectid);
3169                 if (ret && ret != -EEXIST) {
3170                         btrfs_abort_transaction(trans, root, ret);
3171                         return ret;
3172                 }
3173         }
3174         return 0;
3175 }
3176
3177 /*
3178  * We have done the truncate/delete so we can go ahead and remove the orphan
3179  * item for this particular inode.
3180  */
3181 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3182                             struct inode *inode)
3183 {
3184         struct btrfs_root *root = BTRFS_I(inode)->root;
3185         int delete_item = 0;
3186         int release_rsv = 0;
3187         int ret = 0;
3188
3189         spin_lock(&root->orphan_lock);
3190         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3191                                &BTRFS_I(inode)->runtime_flags))
3192                 delete_item = 1;
3193
3194         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3195                                &BTRFS_I(inode)->runtime_flags))
3196                 release_rsv = 1;
3197         spin_unlock(&root->orphan_lock);
3198
3199         if (delete_item) {
3200                 atomic_dec(&root->orphan_inodes);
3201                 if (trans)
3202                         ret = btrfs_del_orphan_item(trans, root,
3203                                                     btrfs_ino(inode));
3204         }
3205
3206         if (release_rsv)
3207                 btrfs_orphan_release_metadata(inode);
3208
3209         return ret;
3210 }
3211
3212 /*
3213  * this cleans up any orphans that may be left on the list from the last use
3214  * of this root.
3215  */
3216 int btrfs_orphan_cleanup(struct btrfs_root *root)
3217 {
3218         struct btrfs_path *path;
3219         struct extent_buffer *leaf;
3220         struct btrfs_key key, found_key;
3221         struct btrfs_trans_handle *trans;
3222         struct inode *inode;
3223         u64 last_objectid = 0;
3224         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3225
3226         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3227                 return 0;
3228
3229         path = btrfs_alloc_path();
3230         if (!path) {
3231                 ret = -ENOMEM;
3232                 goto out;
3233         }
3234         path->reada = -1;
3235
3236         key.objectid = BTRFS_ORPHAN_OBJECTID;
3237         key.type = BTRFS_ORPHAN_ITEM_KEY;
3238         key.offset = (u64)-1;
3239
3240         while (1) {
3241                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3242                 if (ret < 0)
3243                         goto out;
3244
3245                 /*
3246                  * if ret == 0 means we found what we were searching for, which
3247                  * is weird, but possible, so only screw with path if we didn't
3248                  * find the key and see if we have stuff that matches
3249                  */
3250                 if (ret > 0) {
3251                         ret = 0;
3252                         if (path->slots[0] == 0)
3253                                 break;
3254                         path->slots[0]--;
3255                 }
3256
3257                 /* pull out the item */
3258                 leaf = path->nodes[0];
3259                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3260
3261                 /* make sure the item matches what we want */
3262                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3263                         break;
3264                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3265                         break;
3266
3267                 /* release the path since we're done with it */
3268                 btrfs_release_path(path);
3269
3270                 /*
3271                  * this is where we are basically btrfs_lookup, without the
3272                  * crossing root thing.  we store the inode number in the
3273                  * offset of the orphan item.
3274                  */
3275
3276                 if (found_key.offset == last_objectid) {
3277                         btrfs_err(root->fs_info,
3278                                 "Error removing orphan entry, stopping orphan cleanup");
3279                         ret = -EINVAL;
3280                         goto out;
3281                 }
3282
3283                 last_objectid = found_key.offset;
3284
3285                 found_key.objectid = found_key.offset;
3286                 found_key.type = BTRFS_INODE_ITEM_KEY;
3287                 found_key.offset = 0;
3288                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3289                 ret = PTR_ERR_OR_ZERO(inode);
3290                 if (ret && ret != -ESTALE)
3291                         goto out;
3292
3293                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3294                         struct btrfs_root *dead_root;
3295                         struct btrfs_fs_info *fs_info = root->fs_info;
3296                         int is_dead_root = 0;
3297
3298                         /*
3299                          * this is an orphan in the tree root. Currently these
3300                          * could come from 2 sources:
3301                          *  a) a snapshot deletion in progress
3302                          *  b) a free space cache inode
3303                          * We need to distinguish those two, as the snapshot
3304                          * orphan must not get deleted.
3305                          * find_dead_roots already ran before us, so if this
3306                          * is a snapshot deletion, we should find the root
3307                          * in the dead_roots list
3308                          */
3309                         spin_lock(&fs_info->trans_lock);
3310                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3311                                             root_list) {
3312                                 if (dead_root->root_key.objectid ==
3313                                     found_key.objectid) {
3314                                         is_dead_root = 1;
3315                                         break;
3316                                 }
3317                         }
3318                         spin_unlock(&fs_info->trans_lock);
3319                         if (is_dead_root) {
3320                                 /* prevent this orphan from being found again */
3321                                 key.offset = found_key.objectid - 1;
3322                                 continue;
3323                         }
3324                 }
3325                 /*
3326                  * Inode is already gone but the orphan item is still there,
3327                  * kill the orphan item.
3328                  */
3329                 if (ret == -ESTALE) {
3330                         trans = btrfs_start_transaction(root, 1);
3331                         if (IS_ERR(trans)) {
3332                                 ret = PTR_ERR(trans);
3333                                 goto out;
3334                         }
3335                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3336                                 found_key.objectid);
3337                         ret = btrfs_del_orphan_item(trans, root,
3338                                                     found_key.objectid);
3339                         btrfs_end_transaction(trans, root);
3340                         if (ret)
3341                                 goto out;
3342                         continue;
3343                 }
3344
3345                 /*
3346                  * add this inode to the orphan list so btrfs_orphan_del does
3347                  * the proper thing when we hit it
3348                  */
3349                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3350                         &BTRFS_I(inode)->runtime_flags);
3351                 atomic_inc(&root->orphan_inodes);
3352
3353                 /* if we have links, this was a truncate, lets do that */
3354                 if (inode->i_nlink) {
3355                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3356                                 iput(inode);
3357                                 continue;
3358                         }
3359                         nr_truncate++;
3360
3361                         /* 1 for the orphan item deletion. */
3362                         trans = btrfs_start_transaction(root, 1);
3363                         if (IS_ERR(trans)) {
3364                                 iput(inode);
3365                                 ret = PTR_ERR(trans);
3366                                 goto out;
3367                         }
3368                         ret = btrfs_orphan_add(trans, inode);
3369                         btrfs_end_transaction(trans, root);
3370                         if (ret) {
3371                                 iput(inode);
3372                                 goto out;
3373                         }
3374
3375                         ret = btrfs_truncate(inode);
3376                         if (ret)
3377                                 btrfs_orphan_del(NULL, inode);
3378                 } else {
3379                         nr_unlink++;
3380                 }
3381
3382                 /* this will do delete_inode and everything for us */
3383                 iput(inode);
3384                 if (ret)
3385                         goto out;
3386         }
3387         /* release the path since we're done with it */
3388         btrfs_release_path(path);
3389
3390         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3391
3392         if (root->orphan_block_rsv)
3393                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3394                                         (u64)-1);
3395
3396         if (root->orphan_block_rsv ||
3397             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3398                 trans = btrfs_join_transaction(root);
3399                 if (!IS_ERR(trans))
3400                         btrfs_end_transaction(trans, root);
3401         }
3402
3403         if (nr_unlink)
3404                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3405         if (nr_truncate)
3406                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3407
3408 out:
3409         if (ret)
3410                 btrfs_err(root->fs_info,
3411                         "could not do orphan cleanup %d", ret);
3412         btrfs_free_path(path);
3413         return ret;
3414 }
3415
3416 /*
3417  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3418  * don't find any xattrs, we know there can't be any acls.
3419  *
3420  * slot is the slot the inode is in, objectid is the objectid of the inode
3421  */
3422 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3423                                           int slot, u64 objectid,
3424                                           int *first_xattr_slot)
3425 {
3426         u32 nritems = btrfs_header_nritems(leaf);
3427         struct btrfs_key found_key;
3428         static u64 xattr_access = 0;
3429         static u64 xattr_default = 0;
3430         int scanned = 0;
3431
3432         if (!xattr_access) {
3433                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3434                                         strlen(POSIX_ACL_XATTR_ACCESS));
3435                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3436                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3437         }
3438
3439         slot++;
3440         *first_xattr_slot = -1;
3441         while (slot < nritems) {
3442                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3443
3444                 /* we found a different objectid, there must not be acls */
3445                 if (found_key.objectid != objectid)
3446                         return 0;
3447
3448                 /* we found an xattr, assume we've got an acl */
3449                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3450                         if (*first_xattr_slot == -1)
3451                                 *first_xattr_slot = slot;
3452                         if (found_key.offset == xattr_access ||
3453                             found_key.offset == xattr_default)
3454                                 return 1;
3455                 }
3456
3457                 /*
3458                  * we found a key greater than an xattr key, there can't
3459                  * be any acls later on
3460                  */
3461                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3462                         return 0;
3463
3464                 slot++;
3465                 scanned++;
3466
3467                 /*
3468                  * it goes inode, inode backrefs, xattrs, extents,
3469                  * so if there are a ton of hard links to an inode there can
3470                  * be a lot of backrefs.  Don't waste time searching too hard,
3471                  * this is just an optimization
3472                  */
3473                 if (scanned >= 8)
3474                         break;
3475         }
3476         /* we hit the end of the leaf before we found an xattr or
3477          * something larger than an xattr.  We have to assume the inode
3478          * has acls
3479          */
3480         if (*first_xattr_slot == -1)
3481                 *first_xattr_slot = slot;
3482         return 1;
3483 }
3484
3485 /*
3486  * read an inode from the btree into the in-memory inode
3487  */
3488 static void btrfs_read_locked_inode(struct inode *inode)
3489 {
3490         struct btrfs_path *path;
3491         struct extent_buffer *leaf;
3492         struct btrfs_inode_item *inode_item;
3493         struct btrfs_root *root = BTRFS_I(inode)->root;
3494         struct btrfs_key location;
3495         unsigned long ptr;
3496         int maybe_acls;
3497         u32 rdev;
3498         int ret;
3499         bool filled = false;
3500         int first_xattr_slot;
3501
3502         ret = btrfs_fill_inode(inode, &rdev);
3503         if (!ret)
3504                 filled = true;
3505
3506         path = btrfs_alloc_path();
3507         if (!path)
3508                 goto make_bad;
3509
3510         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3511
3512         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3513         if (ret)
3514                 goto make_bad;
3515
3516         leaf = path->nodes[0];
3517
3518         if (filled)
3519                 goto cache_index;
3520
3521         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3522                                     struct btrfs_inode_item);
3523         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3524         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3525         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3526         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3527         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3528
3529         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3530         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3531
3532         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3533         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3534
3535         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3536         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3537
3538         BTRFS_I(inode)->i_otime.tv_sec =
3539                 btrfs_timespec_sec(leaf, &inode_item->otime);
3540         BTRFS_I(inode)->i_otime.tv_nsec =
3541                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3542
3543         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3544         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3545         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3546
3547         /*
3548          * If we were modified in the current generation and evicted from memory
3549          * and then re-read we need to do a full sync since we don't have any
3550          * idea about which extents were modified before we were evicted from
3551          * cache.
3552          */
3553         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3554                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3555                         &BTRFS_I(inode)->runtime_flags);
3556
3557         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3558         inode->i_generation = BTRFS_I(inode)->generation;
3559         inode->i_rdev = 0;
3560         rdev = btrfs_inode_rdev(leaf, inode_item);
3561
3562         BTRFS_I(inode)->index_cnt = (u64)-1;
3563         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3564
3565 cache_index:
3566         path->slots[0]++;
3567         if (inode->i_nlink != 1 ||
3568             path->slots[0] >= btrfs_header_nritems(leaf))
3569                 goto cache_acl;
3570
3571         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3572         if (location.objectid != btrfs_ino(inode))
3573                 goto cache_acl;
3574
3575         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3576         if (location.type == BTRFS_INODE_REF_KEY) {
3577                 struct btrfs_inode_ref *ref;
3578
3579                 ref = (struct btrfs_inode_ref *)ptr;
3580                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3581         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3582                 struct btrfs_inode_extref *extref;
3583
3584                 extref = (struct btrfs_inode_extref *)ptr;
3585                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3586                                                                      extref);
3587         }
3588 cache_acl:
3589         /*
3590          * try to precache a NULL acl entry for files that don't have
3591          * any xattrs or acls
3592          */
3593         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3594                                            btrfs_ino(inode), &first_xattr_slot);
3595         if (first_xattr_slot != -1) {
3596                 path->slots[0] = first_xattr_slot;
3597                 ret = btrfs_load_inode_props(inode, path);
3598                 if (ret)
3599                         btrfs_err(root->fs_info,
3600                                   "error loading props for ino %llu (root %llu): %d",
3601                                   btrfs_ino(inode),
3602                                   root->root_key.objectid, ret);
3603         }
3604         btrfs_free_path(path);
3605
3606         if (!maybe_acls)
3607                 cache_no_acl(inode);
3608
3609         switch (inode->i_mode & S_IFMT) {
3610         case S_IFREG:
3611                 inode->i_mapping->a_ops = &btrfs_aops;
3612                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3613                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3614                 inode->i_fop = &btrfs_file_operations;
3615                 inode->i_op = &btrfs_file_inode_operations;
3616                 break;
3617         case S_IFDIR:
3618                 inode->i_fop = &btrfs_dir_file_operations;
3619                 if (root == root->fs_info->tree_root)
3620                         inode->i_op = &btrfs_dir_ro_inode_operations;
3621                 else
3622                         inode->i_op = &btrfs_dir_inode_operations;
3623                 break;
3624         case S_IFLNK:
3625                 inode->i_op = &btrfs_symlink_inode_operations;
3626                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3627                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3628                 break;
3629         default:
3630                 inode->i_op = &btrfs_special_inode_operations;
3631                 init_special_inode(inode, inode->i_mode, rdev);
3632                 break;
3633         }
3634
3635         btrfs_update_iflags(inode);
3636         return;
3637
3638 make_bad:
3639         btrfs_free_path(path);
3640         make_bad_inode(inode);
3641 }
3642
3643 /*
3644  * given a leaf and an inode, copy the inode fields into the leaf
3645  */
3646 static void fill_inode_item(struct btrfs_trans_handle *trans,
3647                             struct extent_buffer *leaf,
3648                             struct btrfs_inode_item *item,
3649                             struct inode *inode)
3650 {
3651         struct btrfs_map_token token;
3652
3653         btrfs_init_map_token(&token);
3654
3655         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3656         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3657         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3658                                    &token);
3659         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3660         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3661
3662         btrfs_set_token_timespec_sec(leaf, &item->atime,
3663                                      inode->i_atime.tv_sec, &token);
3664         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3665                                       inode->i_atime.tv_nsec, &token);
3666
3667         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3668                                      inode->i_mtime.tv_sec, &token);
3669         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3670                                       inode->i_mtime.tv_nsec, &token);
3671
3672         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3673                                      inode->i_ctime.tv_sec, &token);
3674         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3675                                       inode->i_ctime.tv_nsec, &token);
3676
3677         btrfs_set_token_timespec_sec(leaf, &item->otime,
3678                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3679         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3680                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3681
3682         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3683                                      &token);
3684         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3685                                          &token);
3686         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3687         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3688         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3689         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3690         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3691 }
3692
3693 /*
3694  * copy everything in the in-memory inode into the btree.
3695  */
3696 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3697                                 struct btrfs_root *root, struct inode *inode)
3698 {
3699         struct btrfs_inode_item *inode_item;
3700         struct btrfs_path *path;
3701         struct extent_buffer *leaf;
3702         int ret;
3703
3704         path = btrfs_alloc_path();
3705         if (!path)
3706                 return -ENOMEM;
3707
3708         path->leave_spinning = 1;
3709         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3710                                  1);
3711         if (ret) {
3712                 if (ret > 0)
3713                         ret = -ENOENT;
3714                 goto failed;
3715         }
3716
3717         leaf = path->nodes[0];
3718         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3719                                     struct btrfs_inode_item);
3720
3721         fill_inode_item(trans, leaf, inode_item, inode);
3722         btrfs_mark_buffer_dirty(leaf);
3723         btrfs_set_inode_last_trans(trans, inode);
3724         ret = 0;
3725 failed:
3726         btrfs_free_path(path);
3727         return ret;
3728 }
3729
3730 /*
3731  * copy everything in the in-memory inode into the btree.
3732  */
3733 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3734                                 struct btrfs_root *root, struct inode *inode)
3735 {
3736         int ret;
3737
3738         /*
3739          * If the inode is a free space inode, we can deadlock during commit
3740          * if we put it into the delayed code.
3741          *
3742          * The data relocation inode should also be directly updated
3743          * without delay
3744          */
3745         if (!btrfs_is_free_space_inode(inode)
3746             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3747             && !root->fs_info->log_root_recovering) {
3748                 btrfs_update_root_times(trans, root);
3749
3750                 ret = btrfs_delayed_update_inode(trans, root, inode);
3751                 if (!ret)
3752                         btrfs_set_inode_last_trans(trans, inode);
3753                 return ret;
3754         }
3755
3756         return btrfs_update_inode_item(trans, root, inode);
3757 }
3758
3759 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3760                                          struct btrfs_root *root,
3761                                          struct inode *inode)
3762 {
3763         int ret;
3764
3765         ret = btrfs_update_inode(trans, root, inode);
3766         if (ret == -ENOSPC)
3767                 return btrfs_update_inode_item(trans, root, inode);
3768         return ret;
3769 }
3770
3771 /*
3772  * unlink helper that gets used here in inode.c and in the tree logging
3773  * recovery code.  It remove a link in a directory with a given name, and
3774  * also drops the back refs in the inode to the directory
3775  */
3776 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3777                                 struct btrfs_root *root,
3778                                 struct inode *dir, struct inode *inode,
3779                                 const char *name, int name_len)
3780 {
3781         struct btrfs_path *path;
3782         int ret = 0;
3783         struct extent_buffer *leaf;
3784         struct btrfs_dir_item *di;
3785         struct btrfs_key key;
3786         u64 index;
3787         u64 ino = btrfs_ino(inode);
3788         u64 dir_ino = btrfs_ino(dir);
3789
3790         path = btrfs_alloc_path();
3791         if (!path) {
3792                 ret = -ENOMEM;
3793                 goto out;
3794         }
3795
3796         path->leave_spinning = 1;
3797         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3798                                     name, name_len, -1);
3799         if (IS_ERR(di)) {
3800                 ret = PTR_ERR(di);
3801                 goto err;
3802         }
3803         if (!di) {
3804                 ret = -ENOENT;
3805                 goto err;
3806         }
3807         leaf = path->nodes[0];
3808         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3809         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3810         if (ret)
3811                 goto err;
3812         btrfs_release_path(path);
3813
3814         /*
3815          * If we don't have dir index, we have to get it by looking up
3816          * the inode ref, since we get the inode ref, remove it directly,
3817          * it is unnecessary to do delayed deletion.
3818          *
3819          * But if we have dir index, needn't search inode ref to get it.
3820          * Since the inode ref is close to the inode item, it is better
3821          * that we delay to delete it, and just do this deletion when
3822          * we update the inode item.
3823          */
3824         if (BTRFS_I(inode)->dir_index) {
3825                 ret = btrfs_delayed_delete_inode_ref(inode);
3826                 if (!ret) {
3827                         index = BTRFS_I(inode)->dir_index;
3828                         goto skip_backref;
3829                 }
3830         }
3831
3832         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3833                                   dir_ino, &index);
3834         if (ret) {
3835                 btrfs_info(root->fs_info,
3836                         "failed to delete reference to %.*s, inode %llu parent %llu",
3837                         name_len, name, ino, dir_ino);
3838                 btrfs_abort_transaction(trans, root, ret);
3839                 goto err;
3840         }
3841 skip_backref:
3842         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3843         if (ret) {
3844                 btrfs_abort_transaction(trans, root, ret);
3845                 goto err;
3846         }
3847
3848         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3849                                          inode, dir_ino);
3850         if (ret != 0 && ret != -ENOENT) {
3851                 btrfs_abort_transaction(trans, root, ret);
3852                 goto err;
3853         }
3854
3855         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3856                                            dir, index);
3857         if (ret == -ENOENT)
3858                 ret = 0;
3859         else if (ret)
3860                 btrfs_abort_transaction(trans, root, ret);
3861 err:
3862         btrfs_free_path(path);
3863         if (ret)
3864                 goto out;
3865
3866         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3867         inode_inc_iversion(inode);
3868         inode_inc_iversion(dir);
3869         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3870         ret = btrfs_update_inode(trans, root, dir);
3871 out:
3872         return ret;
3873 }
3874
3875 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3876                        struct btrfs_root *root,
3877                        struct inode *dir, struct inode *inode,
3878                        const char *name, int name_len)
3879 {
3880         int ret;
3881         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3882         if (!ret) {
3883                 drop_nlink(inode);
3884                 ret = btrfs_update_inode(trans, root, inode);
3885         }
3886         return ret;
3887 }
3888
3889 /*
3890  * helper to start transaction for unlink and rmdir.
3891  *
3892  * unlink and rmdir are special in btrfs, they do not always free space, so
3893  * if we cannot make our reservations the normal way try and see if there is
3894  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3895  * allow the unlink to occur.
3896  */
3897 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3898 {
3899         struct btrfs_trans_handle *trans;
3900         struct btrfs_root *root = BTRFS_I(dir)->root;
3901         int ret;
3902
3903         /*
3904          * 1 for the possible orphan item
3905          * 1 for the dir item
3906          * 1 for the dir index
3907          * 1 for the inode ref
3908          * 1 for the inode
3909          */
3910         trans = btrfs_start_transaction(root, 5);
3911         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3912                 return trans;
3913
3914         if (PTR_ERR(trans) == -ENOSPC) {
3915                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3916
3917                 trans = btrfs_start_transaction(root, 0);
3918                 if (IS_ERR(trans))
3919                         return trans;
3920                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3921                                                &root->fs_info->trans_block_rsv,
3922                                                num_bytes, 5);
3923                 if (ret) {
3924                         btrfs_end_transaction(trans, root);
3925                         return ERR_PTR(ret);
3926                 }
3927                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3928                 trans->bytes_reserved = num_bytes;
3929         }
3930         return trans;
3931 }
3932
3933 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3934 {
3935         struct btrfs_root *root = BTRFS_I(dir)->root;
3936         struct btrfs_trans_handle *trans;
3937         struct inode *inode = dentry->d_inode;
3938         int ret;
3939
3940         trans = __unlink_start_trans(dir);
3941         if (IS_ERR(trans))
3942                 return PTR_ERR(trans);
3943
3944         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3945
3946         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3947                                  dentry->d_name.name, dentry->d_name.len);
3948         if (ret)
3949                 goto out;
3950
3951         if (inode->i_nlink == 0) {
3952                 ret = btrfs_orphan_add(trans, inode);
3953                 if (ret)
3954                         goto out;
3955         }
3956
3957 out:
3958         btrfs_end_transaction(trans, root);
3959         btrfs_btree_balance_dirty(root);
3960         return ret;
3961 }
3962
3963 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3964                         struct btrfs_root *root,
3965                         struct inode *dir, u64 objectid,
3966                         const char *name, int name_len)
3967 {
3968         struct btrfs_path *path;
3969         struct extent_buffer *leaf;
3970         struct btrfs_dir_item *di;
3971         struct btrfs_key key;
3972         u64 index;
3973         int ret;
3974         u64 dir_ino = btrfs_ino(dir);
3975
3976         path = btrfs_alloc_path();
3977         if (!path)
3978                 return -ENOMEM;
3979
3980         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3981                                    name, name_len, -1);
3982         if (IS_ERR_OR_NULL(di)) {
3983                 if (!di)
3984                         ret = -ENOENT;
3985                 else
3986                         ret = PTR_ERR(di);
3987                 goto out;
3988         }
3989
3990         leaf = path->nodes[0];
3991         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3992         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3993         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3994         if (ret) {
3995                 btrfs_abort_transaction(trans, root, ret);
3996                 goto out;
3997         }
3998         btrfs_release_path(path);
3999
4000         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
4001                                  objectid, root->root_key.objectid,
4002                                  dir_ino, &index, name, name_len);
4003         if (ret < 0) {
4004                 if (ret != -ENOENT) {
4005                         btrfs_abort_transaction(trans, root, ret);
4006                         goto out;
4007                 }
4008                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4009                                                  name, name_len);
4010                 if (IS_ERR_OR_NULL(di)) {
4011                         if (!di)
4012                                 ret = -ENOENT;
4013                         else
4014                                 ret = PTR_ERR(di);
4015                         btrfs_abort_transaction(trans, root, ret);
4016                         goto out;
4017                 }
4018
4019                 leaf = path->nodes[0];
4020                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4021                 btrfs_release_path(path);
4022                 index = key.offset;
4023         }
4024         btrfs_release_path(path);
4025
4026         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4027         if (ret) {
4028                 btrfs_abort_transaction(trans, root, ret);
4029                 goto out;
4030         }
4031
4032         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4033         inode_inc_iversion(dir);
4034         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
4035         ret = btrfs_update_inode_fallback(trans, root, dir);
4036         if (ret)
4037                 btrfs_abort_transaction(trans, root, ret);
4038 out:
4039         btrfs_free_path(path);
4040         return ret;
4041 }
4042
4043 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4044 {
4045         struct inode *inode = dentry->d_inode;
4046         int err = 0;
4047         struct btrfs_root *root = BTRFS_I(dir)->root;
4048         struct btrfs_trans_handle *trans;
4049
4050         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4051                 return -ENOTEMPTY;
4052         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
4053                 return -EPERM;
4054
4055         trans = __unlink_start_trans(dir);
4056         if (IS_ERR(trans))
4057                 return PTR_ERR(trans);
4058
4059         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4060                 err = btrfs_unlink_subvol(trans, root, dir,
4061                                           BTRFS_I(inode)->location.objectid,
4062                                           dentry->d_name.name,
4063                                           dentry->d_name.len);
4064                 goto out;
4065         }
4066
4067         err = btrfs_orphan_add(trans, inode);
4068         if (err)
4069                 goto out;
4070
4071         /* now the directory is empty */
4072         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
4073                                  dentry->d_name.name, dentry->d_name.len);
4074         if (!err)
4075                 btrfs_i_size_write(inode, 0);
4076 out:
4077         btrfs_end_transaction(trans, root);
4078         btrfs_btree_balance_dirty(root);
4079
4080         return err;
4081 }
4082
4083 /*
4084  * this can truncate away extent items, csum items and directory items.
4085  * It starts at a high offset and removes keys until it can't find
4086  * any higher than new_size
4087  *
4088  * csum items that cross the new i_size are truncated to the new size
4089  * as well.
4090  *
4091  * min_type is the minimum key type to truncate down to.  If set to 0, this
4092  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4093  */
4094 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4095                                struct btrfs_root *root,
4096                                struct inode *inode,
4097                                u64 new_size, u32 min_type)
4098 {
4099         struct btrfs_path *path;
4100         struct extent_buffer *leaf;
4101         struct btrfs_file_extent_item *fi;
4102         struct btrfs_key key;
4103         struct btrfs_key found_key;
4104         u64 extent_start = 0;
4105         u64 extent_num_bytes = 0;
4106         u64 extent_offset = 0;
4107         u64 item_end = 0;
4108         u64 last_size = (u64)-1;
4109         u32 found_type = (u8)-1;
4110         int found_extent;
4111         int del_item;
4112         int pending_del_nr = 0;
4113         int pending_del_slot = 0;
4114         int extent_type = -1;
4115         int ret;
4116         int err = 0;
4117         u64 ino = btrfs_ino(inode);
4118
4119         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4120
4121         path = btrfs_alloc_path();
4122         if (!path)
4123                 return -ENOMEM;
4124         path->reada = -1;
4125
4126         /*
4127          * We want to drop from the next block forward in case this new size is
4128          * not block aligned since we will be keeping the last block of the
4129          * extent just the way it is.
4130          */
4131         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4132             root == root->fs_info->tree_root)
4133                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4134                                         root->sectorsize), (u64)-1, 0);
4135
4136         /*
4137          * This function is also used to drop the items in the log tree before
4138          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4139          * it is used to drop the loged items. So we shouldn't kill the delayed
4140          * items.
4141          */
4142         if (min_type == 0 && root == BTRFS_I(inode)->root)
4143                 btrfs_kill_delayed_inode_items(inode);
4144
4145         key.objectid = ino;
4146         key.offset = (u64)-1;
4147         key.type = (u8)-1;
4148
4149 search_again:
4150         path->leave_spinning = 1;
4151         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4152         if (ret < 0) {
4153                 err = ret;
4154                 goto out;
4155         }
4156
4157         if (ret > 0) {
4158                 /* there are no items in the tree for us to truncate, we're
4159                  * done
4160                  */
4161                 if (path->slots[0] == 0)
4162                         goto out;
4163                 path->slots[0]--;
4164         }
4165
4166         while (1) {
4167                 fi = NULL;
4168                 leaf = path->nodes[0];
4169                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4170                 found_type = found_key.type;
4171
4172                 if (found_key.objectid != ino)
4173                         break;
4174
4175                 if (found_type < min_type)
4176                         break;
4177
4178                 item_end = found_key.offset;
4179                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4180                         fi = btrfs_item_ptr(leaf, path->slots[0],
4181                                             struct btrfs_file_extent_item);
4182                         extent_type = btrfs_file_extent_type(leaf, fi);
4183                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4184                                 item_end +=
4185                                     btrfs_file_extent_num_bytes(leaf, fi);
4186                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4187                                 item_end += btrfs_file_extent_inline_len(leaf,
4188                                                          path->slots[0], fi);
4189                         }
4190                         item_end--;
4191                 }
4192                 if (found_type > min_type) {
4193                         del_item = 1;
4194                 } else {
4195                         if (item_end < new_size)
4196                                 break;
4197                         if (found_key.offset >= new_size)
4198                                 del_item = 1;
4199                         else
4200                                 del_item = 0;
4201                 }
4202                 found_extent = 0;
4203                 /* FIXME, shrink the extent if the ref count is only 1 */
4204                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4205                         goto delete;
4206
4207                 if (del_item)
4208                         last_size = found_key.offset;
4209                 else
4210                         last_size = new_size;
4211
4212                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4213                         u64 num_dec;
4214                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4215                         if (!del_item) {
4216                                 u64 orig_num_bytes =
4217                                         btrfs_file_extent_num_bytes(leaf, fi);
4218                                 extent_num_bytes = ALIGN(new_size -
4219                                                 found_key.offset,
4220                                                 root->sectorsize);
4221                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4222                                                          extent_num_bytes);
4223                                 num_dec = (orig_num_bytes -
4224                                            extent_num_bytes);
4225                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4226                                              &root->state) &&
4227                                     extent_start != 0)
4228                                         inode_sub_bytes(inode, num_dec);
4229                                 btrfs_mark_buffer_dirty(leaf);
4230                         } else {
4231                                 extent_num_bytes =
4232                                         btrfs_file_extent_disk_num_bytes(leaf,
4233                                                                          fi);
4234                                 extent_offset = found_key.offset -
4235                                         btrfs_file_extent_offset(leaf, fi);
4236
4237                                 /* FIXME blocksize != 4096 */
4238                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4239                                 if (extent_start != 0) {
4240                                         found_extent = 1;
4241                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4242                                                      &root->state))
4243                                                 inode_sub_bytes(inode, num_dec);
4244                                 }
4245                         }
4246                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4247                         /*
4248                          * we can't truncate inline items that have had
4249                          * special encodings
4250                          */
4251                         if (!del_item &&
4252                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4253                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4254                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4255                                 u32 size = new_size - found_key.offset;
4256
4257                                 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4258                                         inode_sub_bytes(inode, item_end + 1 -
4259                                                         new_size);
4260
4261                                 /*
4262                                  * update the ram bytes to properly reflect
4263                                  * the new size of our item
4264                                  */
4265                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4266                                 size =
4267                                     btrfs_file_extent_calc_inline_size(size);
4268                                 btrfs_truncate_item(root, path, size, 1);
4269                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4270                                             &root->state)) {
4271                                 inode_sub_bytes(inode, item_end + 1 -
4272                                                 found_key.offset);
4273                         }
4274                 }
4275 delete:
4276                 if (del_item) {
4277                         if (!pending_del_nr) {
4278                                 /* no pending yet, add ourselves */
4279                                 pending_del_slot = path->slots[0];
4280                                 pending_del_nr = 1;
4281                         } else if (pending_del_nr &&
4282                                    path->slots[0] + 1 == pending_del_slot) {
4283                                 /* hop on the pending chunk */
4284                                 pending_del_nr++;
4285                                 pending_del_slot = path->slots[0];
4286                         } else {
4287                                 BUG();
4288                         }
4289                 } else {
4290                         break;
4291                 }
4292                 if (found_extent &&
4293                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4294                      root == root->fs_info->tree_root)) {
4295                         btrfs_set_path_blocking(path);
4296                         ret = btrfs_free_extent(trans, root, extent_start,
4297                                                 extent_num_bytes, 0,
4298                                                 btrfs_header_owner(leaf),
4299                                                 ino, extent_offset, 0);
4300                         BUG_ON(ret);
4301                 }
4302
4303                 if (found_type == BTRFS_INODE_ITEM_KEY)
4304                         break;
4305
4306                 if (path->slots[0] == 0 ||
4307                     path->slots[0] != pending_del_slot) {
4308                         if (pending_del_nr) {
4309                                 ret = btrfs_del_items(trans, root, path,
4310                                                 pending_del_slot,
4311                                                 pending_del_nr);
4312                                 if (ret) {
4313                                         btrfs_abort_transaction(trans,
4314                                                                 root, ret);
4315                                         goto error;
4316                                 }
4317                                 pending_del_nr = 0;
4318                         }
4319                         btrfs_release_path(path);
4320                         goto search_again;
4321                 } else {
4322                         path->slots[0]--;
4323                 }
4324         }
4325 out:
4326         if (pending_del_nr) {
4327                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4328                                       pending_del_nr);
4329                 if (ret)
4330                         btrfs_abort_transaction(trans, root, ret);
4331         }
4332 error:
4333         if (last_size != (u64)-1 &&
4334             root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4335                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4336         btrfs_free_path(path);
4337         return err;
4338 }
4339
4340 /*
4341  * btrfs_truncate_page - read, zero a chunk and write a page
4342  * @inode - inode that we're zeroing
4343  * @from - the offset to start zeroing
4344  * @len - the length to zero, 0 to zero the entire range respective to the
4345  *      offset
4346  * @front - zero up to the offset instead of from the offset on
4347  *
4348  * This will find the page for the "from" offset and cow the page and zero the
4349  * part we want to zero.  This is used with truncate and hole punching.
4350  */
4351 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4352                         int front)
4353 {
4354         struct address_space *mapping = inode->i_mapping;
4355         struct btrfs_root *root = BTRFS_I(inode)->root;
4356         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4357         struct btrfs_ordered_extent *ordered;
4358         struct extent_state *cached_state = NULL;
4359         char *kaddr;
4360         u32 blocksize = root->sectorsize;
4361         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4362         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4363         struct page *page;
4364         gfp_t mask = btrfs_alloc_write_mask(mapping);
4365         int ret = 0;
4366         u64 page_start;
4367         u64 page_end;
4368
4369         if ((offset & (blocksize - 1)) == 0 &&
4370             (!len || ((len & (blocksize - 1)) == 0)))
4371                 goto out;
4372         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4373         if (ret)
4374                 goto out;
4375
4376 again:
4377         page = find_or_create_page(mapping, index, mask);
4378         if (!page) {
4379                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4380                 ret = -ENOMEM;
4381                 goto out;
4382         }
4383
4384         page_start = page_offset(page);
4385         page_end = page_start + PAGE_CACHE_SIZE - 1;
4386
4387         if (!PageUptodate(page)) {
4388                 ret = btrfs_readpage(NULL, page);
4389                 lock_page(page);
4390                 if (page->mapping != mapping) {
4391                         unlock_page(page);
4392                         page_cache_release(page);
4393                         goto again;
4394                 }
4395                 if (!PageUptodate(page)) {
4396                         ret = -EIO;
4397                         goto out_unlock;
4398                 }
4399         }
4400         wait_on_page_writeback(page);
4401
4402         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4403         set_page_extent_mapped(page);
4404
4405         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4406         if (ordered) {
4407                 unlock_extent_cached(io_tree, page_start, page_end,
4408                                      &cached_state, GFP_NOFS);
4409                 unlock_page(page);
4410                 page_cache_release(page);
4411                 btrfs_start_ordered_extent(inode, ordered, 1);
4412                 btrfs_put_ordered_extent(ordered);
4413                 goto again;
4414         }
4415
4416         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4417                           EXTENT_DIRTY | EXTENT_DELALLOC |
4418                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4419                           0, 0, &cached_state, GFP_NOFS);
4420
4421         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4422                                         &cached_state);
4423         if (ret) {
4424                 unlock_extent_cached(io_tree, page_start, page_end,
4425                                      &cached_state, GFP_NOFS);
4426                 goto out_unlock;
4427         }
4428
4429         if (offset != PAGE_CACHE_SIZE) {
4430                 if (!len)
4431                         len = PAGE_CACHE_SIZE - offset;
4432                 kaddr = kmap(page);
4433                 if (front)
4434                         memset(kaddr, 0, offset);
4435                 else
4436                         memset(kaddr + offset, 0, len);
4437                 flush_dcache_page(page);
4438                 kunmap(page);
4439         }
4440         ClearPageChecked(page);
4441         set_page_dirty(page);
4442         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4443                              GFP_NOFS);
4444
4445 out_unlock:
4446         if (ret)
4447                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4448         unlock_page(page);
4449         page_cache_release(page);
4450 out:
4451         return ret;
4452 }
4453
4454 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4455                              u64 offset, u64 len)
4456 {
4457         struct btrfs_trans_handle *trans;
4458         int ret;
4459
4460         /*
4461          * Still need to make sure the inode looks like it's been updated so
4462          * that any holes get logged if we fsync.
4463          */
4464         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4465                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4466                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4467                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4468                 return 0;
4469         }
4470
4471         /*
4472          * 1 - for the one we're dropping
4473          * 1 - for the one we're adding
4474          * 1 - for updating the inode.
4475          */
4476         trans = btrfs_start_transaction(root, 3);
4477         if (IS_ERR(trans))
4478                 return PTR_ERR(trans);
4479
4480         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4481         if (ret) {
4482                 btrfs_abort_transaction(trans, root, ret);
4483                 btrfs_end_transaction(trans, root);
4484                 return ret;
4485         }
4486
4487         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4488                                        0, 0, len, 0, len, 0, 0, 0);
4489         if (ret)
4490                 btrfs_abort_transaction(trans, root, ret);
4491         else
4492                 btrfs_update_inode(trans, root, inode);
4493         btrfs_end_transaction(trans, root);
4494         return ret;
4495 }
4496
4497 /*
4498  * This function puts in dummy file extents for the area we're creating a hole
4499  * for.  So if we are truncating this file to a larger size we need to insert
4500  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4501  * the range between oldsize and size
4502  */
4503 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4504 {
4505         struct btrfs_root *root = BTRFS_I(inode)->root;
4506         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4507         struct extent_map *em = NULL;
4508         struct extent_state *cached_state = NULL;
4509         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4510         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4511         u64 block_end = ALIGN(size, root->sectorsize);
4512         u64 last_byte;
4513         u64 cur_offset;
4514         u64 hole_size;
4515         int err = 0;
4516
4517         /*
4518          * If our size started in the middle of a page we need to zero out the
4519          * rest of the page before we expand the i_size, otherwise we could
4520          * expose stale data.
4521          */
4522         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4523         if (err)
4524                 return err;
4525
4526         if (size <= hole_start)
4527                 return 0;
4528
4529         while (1) {
4530                 struct btrfs_ordered_extent *ordered;
4531
4532                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4533                                  &cached_state);
4534                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4535                                                      block_end - hole_start);
4536                 if (!ordered)
4537                         break;
4538                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4539                                      &cached_state, GFP_NOFS);
4540                 btrfs_start_ordered_extent(inode, ordered, 1);
4541                 btrfs_put_ordered_extent(ordered);
4542         }
4543
4544         cur_offset = hole_start;
4545         while (1) {
4546                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4547                                 block_end - cur_offset, 0);
4548                 if (IS_ERR(em)) {
4549                         err = PTR_ERR(em);
4550                         em = NULL;
4551                         break;
4552                 }
4553                 last_byte = min(extent_map_end(em), block_end);
4554                 last_byte = ALIGN(last_byte , root->sectorsize);
4555                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4556                         struct extent_map *hole_em;
4557                         hole_size = last_byte - cur_offset;
4558
4559                         err = maybe_insert_hole(root, inode, cur_offset,
4560                                                 hole_size);
4561                         if (err)
4562                                 break;
4563                         btrfs_drop_extent_cache(inode, cur_offset,
4564                                                 cur_offset + hole_size - 1, 0);
4565                         hole_em = alloc_extent_map();
4566                         if (!hole_em) {
4567                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4568                                         &BTRFS_I(inode)->runtime_flags);
4569                                 goto next;
4570                         }
4571                         hole_em->start = cur_offset;
4572                         hole_em->len = hole_size;
4573                         hole_em->orig_start = cur_offset;
4574
4575                         hole_em->block_start = EXTENT_MAP_HOLE;
4576                         hole_em->block_len = 0;
4577                         hole_em->orig_block_len = 0;
4578                         hole_em->ram_bytes = hole_size;
4579                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4580                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4581                         hole_em->generation = root->fs_info->generation;
4582
4583                         while (1) {
4584                                 write_lock(&em_tree->lock);
4585                                 err = add_extent_mapping(em_tree, hole_em, 1);
4586                                 write_unlock(&em_tree->lock);
4587                                 if (err != -EEXIST)
4588                                         break;
4589                                 btrfs_drop_extent_cache(inode, cur_offset,
4590                                                         cur_offset +
4591                                                         hole_size - 1, 0);
4592                         }
4593                         free_extent_map(hole_em);
4594                 }
4595 next:
4596                 free_extent_map(em);
4597                 em = NULL;
4598                 cur_offset = last_byte;
4599                 if (cur_offset >= block_end)
4600                         break;
4601         }
4602         free_extent_map(em);
4603         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4604                              GFP_NOFS);
4605         return err;
4606 }
4607
4608 static int wait_snapshoting_atomic_t(atomic_t *a)
4609 {
4610         schedule();
4611         return 0;
4612 }
4613
4614 static void wait_for_snapshot_creation(struct btrfs_root *root)
4615 {
4616         while (true) {
4617                 int ret;
4618
4619                 ret = btrfs_start_write_no_snapshoting(root);
4620                 if (ret)
4621                         break;
4622                 wait_on_atomic_t(&root->will_be_snapshoted,
4623                                  wait_snapshoting_atomic_t,
4624                                  TASK_UNINTERRUPTIBLE);
4625         }
4626 }
4627
4628 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4629 {
4630         struct btrfs_root *root = BTRFS_I(inode)->root;
4631         struct btrfs_trans_handle *trans;
4632         loff_t oldsize = i_size_read(inode);
4633         loff_t newsize = attr->ia_size;
4634         int mask = attr->ia_valid;
4635         int ret;
4636
4637         /*
4638          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4639          * special case where we need to update the times despite not having
4640          * these flags set.  For all other operations the VFS set these flags
4641          * explicitly if it wants a timestamp update.
4642          */
4643         if (newsize != oldsize) {
4644                 inode_inc_iversion(inode);
4645                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4646                         inode->i_ctime = inode->i_mtime =
4647                                 current_fs_time(inode->i_sb);
4648         }
4649
4650         if (newsize > oldsize) {
4651                 truncate_pagecache(inode, newsize);
4652                 /*
4653                  * Don't do an expanding truncate while snapshoting is ongoing.
4654                  * This is to ensure the snapshot captures a fully consistent
4655                  * state of this file - if the snapshot captures this expanding
4656                  * truncation, it must capture all writes that happened before
4657                  * this truncation.
4658                  */
4659                 wait_for_snapshot_creation(root);
4660                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4661                 if (ret) {
4662                         btrfs_end_write_no_snapshoting(root);
4663                         return ret;
4664                 }
4665
4666                 trans = btrfs_start_transaction(root, 1);
4667                 if (IS_ERR(trans)) {
4668                         btrfs_end_write_no_snapshoting(root);
4669                         return PTR_ERR(trans);
4670                 }
4671
4672                 i_size_write(inode, newsize);
4673                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4674                 ret = btrfs_update_inode(trans, root, inode);
4675                 btrfs_end_write_no_snapshoting(root);
4676                 btrfs_end_transaction(trans, root);
4677         } else {
4678
4679                 /*
4680                  * We're truncating a file that used to have good data down to
4681                  * zero. Make sure it gets into the ordered flush list so that
4682                  * any new writes get down to disk quickly.
4683                  */
4684                 if (newsize == 0)
4685                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4686                                 &BTRFS_I(inode)->runtime_flags);
4687
4688                 /*
4689                  * 1 for the orphan item we're going to add
4690                  * 1 for the orphan item deletion.
4691                  */
4692                 trans = btrfs_start_transaction(root, 2);
4693                 if (IS_ERR(trans))
4694                         return PTR_ERR(trans);
4695
4696                 /*
4697                  * We need to do this in case we fail at _any_ point during the
4698                  * actual truncate.  Once we do the truncate_setsize we could
4699                  * invalidate pages which forces any outstanding ordered io to
4700                  * be instantly completed which will give us extents that need
4701                  * to be truncated.  If we fail to get an orphan inode down we
4702                  * could have left over extents that were never meant to live,
4703                  * so we need to garuntee from this point on that everything
4704                  * will be consistent.
4705                  */
4706                 ret = btrfs_orphan_add(trans, inode);
4707                 btrfs_end_transaction(trans, root);
4708                 if (ret)
4709                         return ret;
4710
4711                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4712                 truncate_setsize(inode, newsize);
4713
4714                 /* Disable nonlocked read DIO to avoid the end less truncate */
4715                 btrfs_inode_block_unlocked_dio(inode);
4716                 inode_dio_wait(inode);
4717                 btrfs_inode_resume_unlocked_dio(inode);
4718
4719                 ret = btrfs_truncate(inode);
4720                 if (ret && inode->i_nlink) {
4721                         int err;
4722
4723                         /*
4724                          * failed to truncate, disk_i_size is only adjusted down
4725                          * as we remove extents, so it should represent the true
4726                          * size of the inode, so reset the in memory size and
4727                          * delete our orphan entry.
4728                          */
4729                         trans = btrfs_join_transaction(root);
4730                         if (IS_ERR(trans)) {
4731                                 btrfs_orphan_del(NULL, inode);
4732                                 return ret;
4733                         }
4734                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4735                         err = btrfs_orphan_del(trans, inode);
4736                         if (err)
4737                                 btrfs_abort_transaction(trans, root, err);
4738                         btrfs_end_transaction(trans, root);
4739                 }
4740         }
4741
4742         return ret;
4743 }
4744
4745 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4746 {
4747         struct inode *inode = dentry->d_inode;
4748         struct btrfs_root *root = BTRFS_I(inode)->root;
4749         int err;
4750
4751         if (btrfs_root_readonly(root))
4752                 return -EROFS;
4753
4754         err = inode_change_ok(inode, attr);
4755         if (err)
4756                 return err;
4757
4758         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4759                 err = btrfs_setsize(inode, attr);
4760                 if (err)
4761                         return err;
4762         }
4763
4764         if (attr->ia_valid) {
4765                 setattr_copy(inode, attr);
4766                 inode_inc_iversion(inode);
4767                 err = btrfs_dirty_inode(inode);
4768
4769                 if (!err && attr->ia_valid & ATTR_MODE)
4770                         err = posix_acl_chmod(inode, inode->i_mode);
4771         }
4772
4773         return err;
4774 }
4775
4776 /*
4777  * While truncating the inode pages during eviction, we get the VFS calling
4778  * btrfs_invalidatepage() against each page of the inode. This is slow because
4779  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4780  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4781  * extent_state structures over and over, wasting lots of time.
4782  *
4783  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4784  * those expensive operations on a per page basis and do only the ordered io
4785  * finishing, while we release here the extent_map and extent_state structures,
4786  * without the excessive merging and splitting.
4787  */
4788 static void evict_inode_truncate_pages(struct inode *inode)
4789 {
4790         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4791         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4792         struct rb_node *node;
4793
4794         ASSERT(inode->i_state & I_FREEING);
4795         truncate_inode_pages_final(&inode->i_data);
4796
4797         write_lock(&map_tree->lock);
4798         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4799                 struct extent_map *em;
4800
4801                 node = rb_first(&map_tree->map);
4802                 em = rb_entry(node, struct extent_map, rb_node);
4803                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4804                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4805                 remove_extent_mapping(map_tree, em);
4806                 free_extent_map(em);
4807                 if (need_resched()) {
4808                         write_unlock(&map_tree->lock);
4809                         cond_resched();
4810                         write_lock(&map_tree->lock);
4811                 }
4812         }
4813         write_unlock(&map_tree->lock);
4814
4815         spin_lock(&io_tree->lock);
4816         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4817                 struct extent_state *state;
4818                 struct extent_state *cached_state = NULL;
4819
4820                 node = rb_first(&io_tree->state);
4821                 state = rb_entry(node, struct extent_state, rb_node);
4822                 atomic_inc(&state->refs);
4823                 spin_unlock(&io_tree->lock);
4824
4825                 lock_extent_bits(io_tree, state->start, state->end,
4826                                  0, &cached_state);
4827                 clear_extent_bit(io_tree, state->start, state->end,
4828                                  EXTENT_LOCKED | EXTENT_DIRTY |
4829                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4830                                  EXTENT_DEFRAG, 1, 1,
4831                                  &cached_state, GFP_NOFS);
4832                 free_extent_state(state);
4833
4834                 cond_resched();
4835                 spin_lock(&io_tree->lock);
4836         }
4837         spin_unlock(&io_tree->lock);
4838 }
4839
4840 void btrfs_evict_inode(struct inode *inode)
4841 {
4842         struct btrfs_trans_handle *trans;
4843         struct btrfs_root *root = BTRFS_I(inode)->root;
4844         struct btrfs_block_rsv *rsv, *global_rsv;
4845         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4846         int ret;
4847
4848         trace_btrfs_inode_evict(inode);
4849
4850         evict_inode_truncate_pages(inode);
4851
4852         if (inode->i_nlink &&
4853             ((btrfs_root_refs(&root->root_item) != 0 &&
4854               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4855              btrfs_is_free_space_inode(inode)))
4856                 goto no_delete;
4857
4858         if (is_bad_inode(inode)) {
4859                 btrfs_orphan_del(NULL, inode);
4860                 goto no_delete;
4861         }
4862         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4863         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4864
4865         btrfs_free_io_failure_record(inode, 0, (u64)-1);
4866
4867         if (root->fs_info->log_root_recovering) {
4868                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4869                                  &BTRFS_I(inode)->runtime_flags));
4870                 goto no_delete;
4871         }
4872
4873         if (inode->i_nlink > 0) {
4874                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4875                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4876                 goto no_delete;
4877         }
4878
4879         ret = btrfs_commit_inode_delayed_inode(inode);
4880         if (ret) {
4881                 btrfs_orphan_del(NULL, inode);
4882                 goto no_delete;
4883         }
4884
4885         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4886         if (!rsv) {
4887                 btrfs_orphan_del(NULL, inode);
4888                 goto no_delete;
4889         }
4890         rsv->size = min_size;
4891         rsv->failfast = 1;
4892         global_rsv = &root->fs_info->global_block_rsv;
4893
4894         btrfs_i_size_write(inode, 0);
4895
4896         /*
4897          * This is a bit simpler than btrfs_truncate since we've already
4898          * reserved our space for our orphan item in the unlink, so we just
4899          * need to reserve some slack space in case we add bytes and update
4900          * inode item when doing the truncate.
4901          */
4902         while (1) {
4903                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4904                                              BTRFS_RESERVE_FLUSH_LIMIT);
4905
4906                 /*
4907                  * Try and steal from the global reserve since we will
4908                  * likely not use this space anyway, we want to try as
4909                  * hard as possible to get this to work.
4910                  */
4911                 if (ret)
4912                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4913
4914                 if (ret) {
4915                         btrfs_warn(root->fs_info,
4916                                 "Could not get space for a delete, will truncate on mount %d",
4917                                 ret);
4918                         btrfs_orphan_del(NULL, inode);
4919                         btrfs_free_block_rsv(root, rsv);
4920                         goto no_delete;
4921                 }
4922
4923                 trans = btrfs_join_transaction(root);
4924                 if (IS_ERR(trans)) {
4925                         btrfs_orphan_del(NULL, inode);
4926                         btrfs_free_block_rsv(root, rsv);
4927                         goto no_delete;
4928                 }
4929
4930                 trans->block_rsv = rsv;
4931
4932                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4933                 if (ret != -ENOSPC)
4934                         break;
4935
4936                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4937                 btrfs_end_transaction(trans, root);
4938                 trans = NULL;
4939                 btrfs_btree_balance_dirty(root);
4940         }
4941
4942         btrfs_free_block_rsv(root, rsv);
4943
4944         /*
4945          * Errors here aren't a big deal, it just means we leave orphan items
4946          * in the tree.  They will be cleaned up on the next mount.
4947          */
4948         if (ret == 0) {
4949                 trans->block_rsv = root->orphan_block_rsv;
4950                 btrfs_orphan_del(trans, inode);
4951         } else {
4952                 btrfs_orphan_del(NULL, inode);
4953         }
4954
4955         trans->block_rsv = &root->fs_info->trans_block_rsv;
4956         if (!(root == root->fs_info->tree_root ||
4957               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4958                 btrfs_return_ino(root, btrfs_ino(inode));
4959
4960         btrfs_end_transaction(trans, root);
4961         btrfs_btree_balance_dirty(root);
4962 no_delete:
4963         btrfs_remove_delayed_node(inode);
4964         clear_inode(inode);
4965         return;
4966 }
4967
4968 /*
4969  * this returns the key found in the dir entry in the location pointer.
4970  * If no dir entries were found, location->objectid is 0.
4971  */
4972 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4973                                struct btrfs_key *location)
4974 {
4975         const char *name = dentry->d_name.name;
4976         int namelen = dentry->d_name.len;
4977         struct btrfs_dir_item *di;
4978         struct btrfs_path *path;
4979         struct btrfs_root *root = BTRFS_I(dir)->root;
4980         int ret = 0;
4981
4982         path = btrfs_alloc_path();
4983         if (!path)
4984                 return -ENOMEM;
4985
4986         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4987                                     namelen, 0);
4988         if (IS_ERR(di))
4989                 ret = PTR_ERR(di);
4990
4991         if (IS_ERR_OR_NULL(di))
4992                 goto out_err;
4993
4994         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4995 out:
4996         btrfs_free_path(path);
4997         return ret;
4998 out_err:
4999         location->objectid = 0;
5000         goto out;
5001 }
5002
5003 /*
5004  * when we hit a tree root in a directory, the btrfs part of the inode
5005  * needs to be changed to reflect the root directory of the tree root.  This
5006  * is kind of like crossing a mount point.
5007  */
5008 static int fixup_tree_root_location(struct btrfs_root *root,
5009                                     struct inode *dir,
5010                                     struct dentry *dentry,
5011                                     struct btrfs_key *location,
5012                                     struct btrfs_root **sub_root)
5013 {
5014         struct btrfs_path *path;
5015         struct btrfs_root *new_root;
5016         struct btrfs_root_ref *ref;
5017         struct extent_buffer *leaf;
5018         struct btrfs_key key;
5019         int ret;
5020         int err = 0;
5021
5022         path = btrfs_alloc_path();
5023         if (!path) {
5024                 err = -ENOMEM;
5025                 goto out;
5026         }
5027
5028         err = -ENOENT;
5029         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5030         key.type = BTRFS_ROOT_REF_KEY;
5031         key.offset = location->objectid;
5032
5033         ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key, path,
5034                                 0, 0);
5035         if (ret) {
5036                 if (ret < 0)
5037                         err = ret;
5038                 goto out;
5039         }
5040
5041         leaf = path->nodes[0];
5042         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5043         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
5044             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5045                 goto out;
5046
5047         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5048                                    (unsigned long)(ref + 1),
5049                                    dentry->d_name.len);
5050         if (ret)
5051                 goto out;
5052
5053         btrfs_release_path(path);
5054
5055         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
5056         if (IS_ERR(new_root)) {
5057                 err = PTR_ERR(new_root);
5058                 goto out;
5059         }
5060
5061         *sub_root = new_root;
5062         location->objectid = btrfs_root_dirid(&new_root->root_item);
5063         location->type = BTRFS_INODE_ITEM_KEY;
5064         location->offset = 0;
5065         err = 0;
5066 out:
5067         btrfs_free_path(path);
5068         return err;
5069 }
5070
5071 static void inode_tree_add(struct inode *inode)
5072 {
5073         struct btrfs_root *root = BTRFS_I(inode)->root;
5074         struct btrfs_inode *entry;
5075         struct rb_node **p;
5076         struct rb_node *parent;
5077         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5078         u64 ino = btrfs_ino(inode);
5079
5080         if (inode_unhashed(inode))
5081                 return;
5082         parent = NULL;
5083         spin_lock(&root->inode_lock);
5084         p = &root->inode_tree.rb_node;
5085         while (*p) {
5086                 parent = *p;
5087                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5088
5089                 if (ino < btrfs_ino(&entry->vfs_inode))
5090                         p = &parent->rb_left;
5091                 else if (ino > btrfs_ino(&entry->vfs_inode))
5092                         p = &parent->rb_right;
5093                 else {
5094                         WARN_ON(!(entry->vfs_inode.i_state &
5095                                   (I_WILL_FREE | I_FREEING)));
5096                         rb_replace_node(parent, new, &root->inode_tree);
5097                         RB_CLEAR_NODE(parent);
5098                         spin_unlock(&root->inode_lock);
5099                         return;
5100                 }
5101         }
5102         rb_link_node(new, parent, p);
5103         rb_insert_color(new, &root->inode_tree);
5104         spin_unlock(&root->inode_lock);
5105 }
5106
5107 static void inode_tree_del(struct inode *inode)
5108 {
5109         struct btrfs_root *root = BTRFS_I(inode)->root;
5110         int empty = 0;
5111
5112         spin_lock(&root->inode_lock);
5113         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5114                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5115                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5116                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5117         }
5118         spin_unlock(&root->inode_lock);
5119
5120         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5121                 synchronize_srcu(&root->fs_info->subvol_srcu);
5122                 spin_lock(&root->inode_lock);
5123                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5124                 spin_unlock(&root->inode_lock);
5125                 if (empty)
5126                         btrfs_add_dead_root(root);
5127         }
5128 }
5129
5130 void btrfs_invalidate_inodes(struct btrfs_root *root)
5131 {
5132         struct rb_node *node;
5133         struct rb_node *prev;
5134         struct btrfs_inode *entry;
5135         struct inode *inode;
5136         u64 objectid = 0;
5137
5138         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
5139                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5140
5141         spin_lock(&root->inode_lock);
5142 again:
5143         node = root->inode_tree.rb_node;
5144         prev = NULL;
5145         while (node) {
5146                 prev = node;
5147                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5148
5149                 if (objectid < btrfs_ino(&entry->vfs_inode))
5150                         node = node->rb_left;
5151                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5152                         node = node->rb_right;
5153                 else
5154                         break;
5155         }
5156         if (!node) {
5157                 while (prev) {
5158                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5159                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5160                                 node = prev;
5161                                 break;
5162                         }
5163                         prev = rb_next(prev);
5164                 }
5165         }
5166         while (node) {
5167                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5168                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5169                 inode = igrab(&entry->vfs_inode);
5170                 if (inode) {
5171                         spin_unlock(&root->inode_lock);
5172                         if (atomic_read(&inode->i_count) > 1)
5173                                 d_prune_aliases(inode);
5174                         /*
5175                          * btrfs_drop_inode will have it removed from
5176                          * the inode cache when its usage count
5177                          * hits zero.
5178                          */
5179                         iput(inode);
5180                         cond_resched();
5181                         spin_lock(&root->inode_lock);
5182                         goto again;
5183                 }
5184
5185                 if (cond_resched_lock(&root->inode_lock))
5186                         goto again;
5187
5188                 node = rb_next(node);
5189         }
5190         spin_unlock(&root->inode_lock);
5191 }
5192
5193 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5194 {
5195         struct btrfs_iget_args *args = p;
5196         inode->i_ino = args->location->objectid;
5197         memcpy(&BTRFS_I(inode)->location, args->location,
5198                sizeof(*args->location));
5199         BTRFS_I(inode)->root = args->root;
5200         return 0;
5201 }
5202
5203 static int btrfs_find_actor(struct inode *inode, void *opaque)
5204 {
5205         struct btrfs_iget_args *args = opaque;
5206         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5207                 args->root == BTRFS_I(inode)->root;
5208 }
5209
5210 static struct inode *btrfs_iget_locked(struct super_block *s,
5211                                        struct btrfs_key *location,
5212                                        struct btrfs_root *root)
5213 {
5214         struct inode *inode;
5215         struct btrfs_iget_args args;
5216         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5217
5218         args.location = location;
5219         args.root = root;
5220
5221         inode = iget5_locked(s, hashval, btrfs_find_actor,
5222                              btrfs_init_locked_inode,
5223                              (void *)&args);
5224         return inode;
5225 }
5226
5227 /* Get an inode object given its location and corresponding root.
5228  * Returns in *is_new if the inode was read from disk
5229  */
5230 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5231                          struct btrfs_root *root, int *new)
5232 {
5233         struct inode *inode;
5234
5235         inode = btrfs_iget_locked(s, location, root);
5236         if (!inode)
5237                 return ERR_PTR(-ENOMEM);
5238
5239         if (inode->i_state & I_NEW) {
5240                 btrfs_read_locked_inode(inode);
5241                 if (!is_bad_inode(inode)) {
5242                         inode_tree_add(inode);
5243                         unlock_new_inode(inode);
5244                         if (new)
5245                                 *new = 1;
5246                 } else {
5247                         unlock_new_inode(inode);
5248                         iput(inode);
5249                         inode = ERR_PTR(-ESTALE);
5250                 }
5251         }
5252
5253         return inode;
5254 }
5255
5256 static struct inode *new_simple_dir(struct super_block *s,
5257                                     struct btrfs_key *key,
5258                                     struct btrfs_root *root)
5259 {
5260         struct inode *inode = new_inode(s);
5261
5262         if (!inode)
5263                 return ERR_PTR(-ENOMEM);
5264
5265         BTRFS_I(inode)->root = root;
5266         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5267         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5268
5269         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5270         inode->i_op = &btrfs_dir_ro_inode_operations;
5271         inode->i_fop = &simple_dir_operations;
5272         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5273         inode->i_mtime = CURRENT_TIME;
5274         inode->i_atime = inode->i_mtime;
5275         inode->i_ctime = inode->i_mtime;
5276         BTRFS_I(inode)->i_otime = inode->i_mtime;
5277
5278         return inode;
5279 }
5280
5281 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5282 {
5283         struct inode *inode;
5284         struct btrfs_root *root = BTRFS_I(dir)->root;
5285         struct btrfs_root *sub_root = root;
5286         struct btrfs_key location;
5287         int index;
5288         int ret = 0;
5289
5290         if (dentry->d_name.len > BTRFS_NAME_LEN)
5291                 return ERR_PTR(-ENAMETOOLONG);
5292
5293         ret = btrfs_inode_by_name(dir, dentry, &location);
5294         if (ret < 0)
5295                 return ERR_PTR(ret);
5296
5297         if (location.objectid == 0)
5298                 return ERR_PTR(-ENOENT);
5299
5300         if (location.type == BTRFS_INODE_ITEM_KEY) {
5301                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5302                 return inode;
5303         }
5304
5305         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5306
5307         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5308         ret = fixup_tree_root_location(root, dir, dentry,
5309                                        &location, &sub_root);
5310         if (ret < 0) {
5311                 if (ret != -ENOENT)
5312                         inode = ERR_PTR(ret);
5313                 else
5314                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5315         } else {
5316                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5317         }
5318         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5319
5320         if (!IS_ERR(inode) && root != sub_root) {
5321                 down_read(&root->fs_info->cleanup_work_sem);
5322                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5323                         ret = btrfs_orphan_cleanup(sub_root);
5324                 up_read(&root->fs_info->cleanup_work_sem);
5325                 if (ret) {
5326                         iput(inode);
5327                         inode = ERR_PTR(ret);
5328                 }
5329         }
5330
5331         return inode;
5332 }
5333
5334 static int btrfs_dentry_delete(const struct dentry *dentry)
5335 {
5336         struct btrfs_root *root;
5337         struct inode *inode = dentry->d_inode;
5338
5339         if (!inode && !IS_ROOT(dentry))
5340                 inode = dentry->d_parent->d_inode;
5341
5342         if (inode) {
5343                 root = BTRFS_I(inode)->root;
5344                 if (btrfs_root_refs(&root->root_item) == 0)
5345                         return 1;
5346
5347                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5348                         return 1;
5349         }
5350         return 0;
5351 }
5352
5353 static void btrfs_dentry_release(struct dentry *dentry)
5354 {
5355         kfree(dentry->d_fsdata);
5356 }
5357
5358 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5359                                    unsigned int flags)
5360 {
5361         struct inode *inode;
5362
5363         inode = btrfs_lookup_dentry(dir, dentry);
5364         if (IS_ERR(inode)) {
5365                 if (PTR_ERR(inode) == -ENOENT)
5366                         inode = NULL;
5367                 else
5368                         return ERR_CAST(inode);
5369         }
5370
5371         return d_splice_alias(inode, dentry);
5372 }
5373
5374 unsigned char btrfs_filetype_table[] = {
5375         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5376 };
5377
5378 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5379 {
5380         struct inode *inode = file_inode(file);
5381         struct btrfs_root *root = BTRFS_I(inode)->root;
5382         struct btrfs_item *item;
5383         struct btrfs_dir_item *di;
5384         struct btrfs_key key;
5385         struct btrfs_key found_key;
5386         struct btrfs_path *path;
5387         struct list_head ins_list;
5388         struct list_head del_list;
5389         int ret;
5390         struct extent_buffer *leaf;
5391         int slot;
5392         unsigned char d_type;
5393         int over = 0;
5394         u32 di_cur;
5395         u32 di_total;
5396         u32 di_len;
5397         int key_type = BTRFS_DIR_INDEX_KEY;
5398         char tmp_name[32];
5399         char *name_ptr;
5400         int name_len;
5401         int is_curr = 0;        /* ctx->pos points to the current index? */
5402
5403         /* FIXME, use a real flag for deciding about the key type */
5404         if (root->fs_info->tree_root == root)
5405                 key_type = BTRFS_DIR_ITEM_KEY;
5406
5407         if (!dir_emit_dots(file, ctx))
5408                 return 0;
5409
5410         path = btrfs_alloc_path();
5411         if (!path)
5412                 return -ENOMEM;
5413
5414         path->reada = 1;
5415
5416         if (key_type == BTRFS_DIR_INDEX_KEY) {
5417                 INIT_LIST_HEAD(&ins_list);
5418                 INIT_LIST_HEAD(&del_list);
5419                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5420         }
5421
5422         key.type = key_type;
5423         key.offset = ctx->pos;
5424         key.objectid = btrfs_ino(inode);
5425
5426         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5427         if (ret < 0)
5428                 goto err;
5429
5430         while (1) {
5431                 leaf = path->nodes[0];
5432                 slot = path->slots[0];
5433                 if (slot >= btrfs_header_nritems(leaf)) {
5434                         ret = btrfs_next_leaf(root, path);
5435                         if (ret < 0)
5436                                 goto err;
5437                         else if (ret > 0)
5438                                 break;
5439                         continue;
5440                 }
5441
5442                 item = btrfs_item_nr(slot);
5443                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5444
5445                 if (found_key.objectid != key.objectid)
5446                         break;
5447                 if (found_key.type != key_type)
5448                         break;
5449                 if (found_key.offset < ctx->pos)
5450                         goto next;
5451                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5452                     btrfs_should_delete_dir_index(&del_list,
5453                                                   found_key.offset))
5454                         goto next;
5455
5456                 ctx->pos = found_key.offset;
5457                 is_curr = 1;
5458
5459                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5460                 di_cur = 0;
5461                 di_total = btrfs_item_size(leaf, item);
5462
5463                 while (di_cur < di_total) {
5464                         struct btrfs_key location;
5465
5466                         if (verify_dir_item(root, leaf, di))
5467                                 break;
5468
5469                         name_len = btrfs_dir_name_len(leaf, di);
5470                         if (name_len <= sizeof(tmp_name)) {
5471                                 name_ptr = tmp_name;
5472                         } else {
5473                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5474                                 if (!name_ptr) {
5475                                         ret = -ENOMEM;
5476                                         goto err;
5477                                 }
5478                         }
5479                         read_extent_buffer(leaf, name_ptr,
5480                                            (unsigned long)(di + 1), name_len);
5481
5482                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5483                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5484
5485
5486                         /* is this a reference to our own snapshot? If so
5487                          * skip it.
5488                          *
5489                          * In contrast to old kernels, we insert the snapshot's
5490                          * dir item and dir index after it has been created, so
5491                          * we won't find a reference to our own snapshot. We
5492                          * still keep the following code for backward
5493                          * compatibility.
5494                          */
5495                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5496                             location.objectid == root->root_key.objectid) {
5497                                 over = 0;
5498                                 goto skip;
5499                         }
5500                         over = !dir_emit(ctx, name_ptr, name_len,
5501                                        location.objectid, d_type);
5502
5503 skip:
5504                         if (name_ptr != tmp_name)
5505                                 kfree(name_ptr);
5506
5507                         if (over)
5508                                 goto nopos;
5509                         di_len = btrfs_dir_name_len(leaf, di) +
5510                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5511                         di_cur += di_len;
5512                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5513                 }
5514 next:
5515                 path->slots[0]++;
5516         }
5517
5518         if (key_type == BTRFS_DIR_INDEX_KEY) {
5519                 if (is_curr)
5520                         ctx->pos++;
5521                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5522                 if (ret)
5523                         goto nopos;
5524         }
5525
5526         /* Reached end of directory/root. Bump pos past the last item. */
5527         ctx->pos++;
5528
5529         /*
5530          * Stop new entries from being returned after we return the last
5531          * entry.
5532          *
5533          * New directory entries are assigned a strictly increasing
5534          * offset.  This means that new entries created during readdir
5535          * are *guaranteed* to be seen in the future by that readdir.
5536          * This has broken buggy programs which operate on names as
5537          * they're returned by readdir.  Until we re-use freed offsets
5538          * we have this hack to stop new entries from being returned
5539          * under the assumption that they'll never reach this huge
5540          * offset.
5541          *
5542          * This is being careful not to overflow 32bit loff_t unless the
5543          * last entry requires it because doing so has broken 32bit apps
5544          * in the past.
5545          */
5546         if (key_type == BTRFS_DIR_INDEX_KEY) {
5547                 if (ctx->pos >= INT_MAX)
5548                         ctx->pos = LLONG_MAX;
5549                 else
5550                         ctx->pos = INT_MAX;
5551         }
5552 nopos:
5553         ret = 0;
5554 err:
5555         if (key_type == BTRFS_DIR_INDEX_KEY)
5556                 btrfs_put_delayed_items(&ins_list, &del_list);
5557         btrfs_free_path(path);
5558         return ret;
5559 }
5560
5561 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5562 {
5563         struct btrfs_root *root = BTRFS_I(inode)->root;
5564         struct btrfs_trans_handle *trans;
5565         int ret = 0;
5566         bool nolock = false;
5567
5568         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5569                 return 0;
5570
5571         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5572                 nolock = true;
5573
5574         if (wbc->sync_mode == WB_SYNC_ALL) {
5575                 if (nolock)
5576                         trans = btrfs_join_transaction_nolock(root);
5577                 else
5578                         trans = btrfs_join_transaction(root);
5579                 if (IS_ERR(trans))
5580                         return PTR_ERR(trans);
5581                 ret = btrfs_commit_transaction(trans, root);
5582         }
5583         return ret;
5584 }
5585
5586 /*
5587  * This is somewhat expensive, updating the tree every time the
5588  * inode changes.  But, it is most likely to find the inode in cache.
5589  * FIXME, needs more benchmarking...there are no reasons other than performance
5590  * to keep or drop this code.
5591  */
5592 static int btrfs_dirty_inode(struct inode *inode)
5593 {
5594         struct btrfs_root *root = BTRFS_I(inode)->root;
5595         struct btrfs_trans_handle *trans;
5596         int ret;
5597
5598         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5599                 return 0;
5600
5601         trans = btrfs_join_transaction(root);
5602         if (IS_ERR(trans))
5603                 return PTR_ERR(trans);
5604
5605         ret = btrfs_update_inode(trans, root, inode);
5606         if (ret && ret == -ENOSPC) {
5607                 /* whoops, lets try again with the full transaction */
5608                 btrfs_end_transaction(trans, root);
5609                 trans = btrfs_start_transaction(root, 1);
5610                 if (IS_ERR(trans))
5611                         return PTR_ERR(trans);
5612
5613                 ret = btrfs_update_inode(trans, root, inode);
5614         }
5615         btrfs_end_transaction(trans, root);
5616         if (BTRFS_I(inode)->delayed_node)
5617                 btrfs_balance_delayed_items(root);
5618
5619         return ret;
5620 }
5621
5622 /*
5623  * This is a copy of file_update_time.  We need this so we can return error on
5624  * ENOSPC for updating the inode in the case of file write and mmap writes.
5625  */
5626 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5627                              int flags)
5628 {
5629         struct btrfs_root *root = BTRFS_I(inode)->root;
5630
5631         if (btrfs_root_readonly(root))
5632                 return -EROFS;
5633
5634         if (flags & S_VERSION)
5635                 inode_inc_iversion(inode);
5636         if (flags & S_CTIME)
5637                 inode->i_ctime = *now;
5638         if (flags & S_MTIME)
5639                 inode->i_mtime = *now;
5640         if (flags & S_ATIME)
5641                 inode->i_atime = *now;
5642         return btrfs_dirty_inode(inode);
5643 }
5644
5645 /*
5646  * find the highest existing sequence number in a directory
5647  * and then set the in-memory index_cnt variable to reflect
5648  * free sequence numbers
5649  */
5650 static int btrfs_set_inode_index_count(struct inode *inode)
5651 {
5652         struct btrfs_root *root = BTRFS_I(inode)->root;
5653         struct btrfs_key key, found_key;
5654         struct btrfs_path *path;
5655         struct extent_buffer *leaf;
5656         int ret;
5657
5658         key.objectid = btrfs_ino(inode);
5659         key.type = BTRFS_DIR_INDEX_KEY;
5660         key.offset = (u64)-1;
5661
5662         path = btrfs_alloc_path();
5663         if (!path)
5664                 return -ENOMEM;
5665
5666         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5667         if (ret < 0)
5668                 goto out;
5669         /* FIXME: we should be able to handle this */
5670         if (ret == 0)
5671                 goto out;
5672         ret = 0;
5673
5674         /*
5675          * MAGIC NUMBER EXPLANATION:
5676          * since we search a directory based on f_pos we have to start at 2
5677          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5678          * else has to start at 2
5679          */
5680         if (path->slots[0] == 0) {
5681                 BTRFS_I(inode)->index_cnt = 2;
5682                 goto out;
5683         }
5684
5685         path->slots[0]--;
5686
5687         leaf = path->nodes[0];
5688         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5689
5690         if (found_key.objectid != btrfs_ino(inode) ||
5691             found_key.type != BTRFS_DIR_INDEX_KEY) {
5692                 BTRFS_I(inode)->index_cnt = 2;
5693                 goto out;
5694         }
5695
5696         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5697 out:
5698         btrfs_free_path(path);
5699         return ret;
5700 }
5701
5702 /*
5703  * helper to find a free sequence number in a given directory.  This current
5704  * code is very simple, later versions will do smarter things in the btree
5705  */
5706 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5707 {
5708         int ret = 0;
5709
5710         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5711                 ret = btrfs_inode_delayed_dir_index_count(dir);
5712                 if (ret) {
5713                         ret = btrfs_set_inode_index_count(dir);
5714                         if (ret)
5715                                 return ret;
5716                 }
5717         }
5718
5719         *index = BTRFS_I(dir)->index_cnt;
5720         BTRFS_I(dir)->index_cnt++;
5721
5722         return ret;
5723 }
5724
5725 static int btrfs_insert_inode_locked(struct inode *inode)
5726 {
5727         struct btrfs_iget_args args;
5728         args.location = &BTRFS_I(inode)->location;
5729         args.root = BTRFS_I(inode)->root;
5730
5731         return insert_inode_locked4(inode,
5732                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
5733                    btrfs_find_actor, &args);
5734 }
5735
5736 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5737                                      struct btrfs_root *root,
5738                                      struct inode *dir,
5739                                      const char *name, int name_len,
5740                                      u64 ref_objectid, u64 objectid,
5741                                      umode_t mode, u64 *index)
5742 {
5743         struct inode *inode;
5744         struct btrfs_inode_item *inode_item;
5745         struct btrfs_key *location;
5746         struct btrfs_path *path;
5747         struct btrfs_inode_ref *ref;
5748         struct btrfs_key key[2];
5749         u32 sizes[2];
5750         int nitems = name ? 2 : 1;
5751         unsigned long ptr;
5752         int ret;
5753
5754         path = btrfs_alloc_path();
5755         if (!path)
5756                 return ERR_PTR(-ENOMEM);
5757
5758         inode = new_inode(root->fs_info->sb);
5759         if (!inode) {
5760                 btrfs_free_path(path);
5761                 return ERR_PTR(-ENOMEM);
5762         }
5763
5764         /*
5765          * O_TMPFILE, set link count to 0, so that after this point,
5766          * we fill in an inode item with the correct link count.
5767          */
5768         if (!name)
5769                 set_nlink(inode, 0);
5770
5771         /*
5772          * we have to initialize this early, so we can reclaim the inode
5773          * number if we fail afterwards in this function.
5774          */
5775         inode->i_ino = objectid;
5776
5777         if (dir && name) {
5778                 trace_btrfs_inode_request(dir);
5779
5780                 ret = btrfs_set_inode_index(dir, index);
5781                 if (ret) {
5782                         btrfs_free_path(path);
5783                         iput(inode);
5784                         return ERR_PTR(ret);
5785                 }
5786         } else if (dir) {
5787                 *index = 0;
5788         }
5789         /*
5790          * index_cnt is ignored for everything but a dir,
5791          * btrfs_get_inode_index_count has an explanation for the magic
5792          * number
5793          */
5794         BTRFS_I(inode)->index_cnt = 2;
5795         BTRFS_I(inode)->dir_index = *index;
5796         BTRFS_I(inode)->root = root;
5797         BTRFS_I(inode)->generation = trans->transid;
5798         inode->i_generation = BTRFS_I(inode)->generation;
5799
5800         /*
5801          * We could have gotten an inode number from somebody who was fsynced
5802          * and then removed in this same transaction, so let's just set full
5803          * sync since it will be a full sync anyway and this will blow away the
5804          * old info in the log.
5805          */
5806         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5807
5808         key[0].objectid = objectid;
5809         key[0].type = BTRFS_INODE_ITEM_KEY;
5810         key[0].offset = 0;
5811
5812         sizes[0] = sizeof(struct btrfs_inode_item);
5813
5814         if (name) {
5815                 /*
5816                  * Start new inodes with an inode_ref. This is slightly more
5817                  * efficient for small numbers of hard links since they will
5818                  * be packed into one item. Extended refs will kick in if we
5819                  * add more hard links than can fit in the ref item.
5820                  */
5821                 key[1].objectid = objectid;
5822                 key[1].type = BTRFS_INODE_REF_KEY;
5823                 key[1].offset = ref_objectid;
5824
5825                 sizes[1] = name_len + sizeof(*ref);
5826         }
5827
5828         location = &BTRFS_I(inode)->location;
5829         location->objectid = objectid;
5830         location->offset = 0;
5831         location->type = BTRFS_INODE_ITEM_KEY;
5832
5833         ret = btrfs_insert_inode_locked(inode);
5834         if (ret < 0)
5835                 goto fail;
5836
5837         path->leave_spinning = 1;
5838         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
5839         if (ret != 0)
5840                 goto fail_unlock;
5841
5842         inode_init_owner(inode, dir, mode);
5843         inode_set_bytes(inode, 0);
5844
5845         inode->i_mtime = CURRENT_TIME;
5846         inode->i_atime = inode->i_mtime;
5847         inode->i_ctime = inode->i_mtime;
5848         BTRFS_I(inode)->i_otime = inode->i_mtime;
5849
5850         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5851                                   struct btrfs_inode_item);
5852         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5853                              sizeof(*inode_item));
5854         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5855
5856         if (name) {
5857                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5858                                      struct btrfs_inode_ref);
5859                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5860                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5861                 ptr = (unsigned long)(ref + 1);
5862                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
5863         }
5864
5865         btrfs_mark_buffer_dirty(path->nodes[0]);
5866         btrfs_free_path(path);
5867
5868         btrfs_inherit_iflags(inode, dir);
5869
5870         if (S_ISREG(mode)) {
5871                 if (btrfs_test_opt(root, NODATASUM))
5872                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5873                 if (btrfs_test_opt(root, NODATACOW))
5874                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5875                                 BTRFS_INODE_NODATASUM;
5876         }
5877
5878         inode_tree_add(inode);
5879
5880         trace_btrfs_inode_new(inode);
5881         btrfs_set_inode_last_trans(trans, inode);
5882
5883         btrfs_update_root_times(trans, root);
5884
5885         ret = btrfs_inode_inherit_props(trans, inode, dir);
5886         if (ret)
5887                 btrfs_err(root->fs_info,
5888                           "error inheriting props for ino %llu (root %llu): %d",
5889                           btrfs_ino(inode), root->root_key.objectid, ret);
5890
5891         return inode;
5892
5893 fail_unlock:
5894         unlock_new_inode(inode);
5895 fail:
5896         if (dir && name)
5897                 BTRFS_I(dir)->index_cnt--;
5898         btrfs_free_path(path);
5899         iput(inode);
5900         return ERR_PTR(ret);
5901 }
5902
5903 static inline u8 btrfs_inode_type(struct inode *inode)
5904 {
5905         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5906 }
5907
5908 /*
5909  * utility function to add 'inode' into 'parent_inode' with
5910  * a give name and a given sequence number.
5911  * if 'add_backref' is true, also insert a backref from the
5912  * inode to the parent directory.
5913  */
5914 int btrfs_add_link(struct btrfs_trans_handle *trans,
5915                    struct inode *parent_inode, struct inode *inode,
5916                    const char *name, int name_len, int add_backref, u64 index)
5917 {
5918         int ret = 0;
5919         struct btrfs_key key;
5920         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5921         u64 ino = btrfs_ino(inode);
5922         u64 parent_ino = btrfs_ino(parent_inode);
5923
5924         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5925                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5926         } else {
5927                 key.objectid = ino;
5928                 key.type = BTRFS_INODE_ITEM_KEY;
5929                 key.offset = 0;
5930         }
5931
5932         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5933                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5934                                          key.objectid, root->root_key.objectid,
5935                                          parent_ino, index, name, name_len);
5936         } else if (add_backref) {
5937                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5938                                              parent_ino, index);
5939         }
5940
5941         /* Nothing to clean up yet */
5942         if (ret)
5943                 return ret;
5944
5945         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5946                                     parent_inode, &key,
5947                                     btrfs_inode_type(inode), index);
5948         if (ret == -EEXIST || ret == -EOVERFLOW)
5949                 goto fail_dir_item;
5950         else if (ret) {
5951                 btrfs_abort_transaction(trans, root, ret);
5952                 return ret;
5953         }
5954
5955         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5956                            name_len * 2);
5957         inode_inc_iversion(parent_inode);
5958         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5959         ret = btrfs_update_inode(trans, root, parent_inode);
5960         if (ret)
5961                 btrfs_abort_transaction(trans, root, ret);
5962         return ret;
5963
5964 fail_dir_item:
5965         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5966                 u64 local_index;
5967                 int err;
5968                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5969                                  key.objectid, root->root_key.objectid,
5970                                  parent_ino, &local_index, name, name_len);
5971
5972         } else if (add_backref) {
5973                 u64 local_index;
5974                 int err;
5975
5976                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5977                                           ino, parent_ino, &local_index);
5978         }
5979         return ret;
5980 }
5981
5982 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5983                             struct inode *dir, struct dentry *dentry,
5984                             struct inode *inode, int backref, u64 index)
5985 {
5986         int err = btrfs_add_link(trans, dir, inode,
5987                                  dentry->d_name.name, dentry->d_name.len,
5988                                  backref, index);
5989         if (err > 0)
5990                 err = -EEXIST;
5991         return err;
5992 }
5993
5994 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5995                         umode_t mode, dev_t rdev)
5996 {
5997         struct btrfs_trans_handle *trans;
5998         struct btrfs_root *root = BTRFS_I(dir)->root;
5999         struct inode *inode = NULL;
6000         int err;
6001         int drop_inode = 0;
6002         u64 objectid;
6003         u64 index = 0;
6004
6005         if (!new_valid_dev(rdev))
6006                 return -EINVAL;
6007
6008         /*
6009          * 2 for inode item and ref
6010          * 2 for dir items
6011          * 1 for xattr if selinux is on
6012          */
6013         trans = btrfs_start_transaction(root, 5);
6014         if (IS_ERR(trans))
6015                 return PTR_ERR(trans);
6016
6017         err = btrfs_find_free_ino(root, &objectid);
6018         if (err)
6019                 goto out_unlock;
6020
6021         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6022                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6023                                 mode, &index);
6024         if (IS_ERR(inode)) {
6025                 err = PTR_ERR(inode);
6026                 goto out_unlock;
6027         }
6028
6029         /*
6030         * If the active LSM wants to access the inode during
6031         * d_instantiate it needs these. Smack checks to see
6032         * if the filesystem supports xattrs by looking at the
6033         * ops vector.
6034         */
6035         inode->i_op = &btrfs_special_inode_operations;
6036         init_special_inode(inode, inode->i_mode, rdev);
6037
6038         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6039         if (err)
6040                 goto out_unlock_inode;
6041
6042         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6043         if (err) {
6044                 goto out_unlock_inode;
6045         } else {
6046                 btrfs_update_inode(trans, root, inode);
6047                 unlock_new_inode(inode);
6048                 d_instantiate(dentry, inode);
6049         }
6050
6051 out_unlock:
6052         btrfs_end_transaction(trans, root);
6053         btrfs_balance_delayed_items(root);
6054         btrfs_btree_balance_dirty(root);
6055         if (drop_inode) {
6056                 inode_dec_link_count(inode);
6057                 iput(inode);
6058         }
6059         return err;
6060
6061 out_unlock_inode:
6062         drop_inode = 1;
6063         unlock_new_inode(inode);
6064         goto out_unlock;
6065
6066 }
6067
6068 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6069                         umode_t mode, bool excl)
6070 {
6071         struct btrfs_trans_handle *trans;
6072         struct btrfs_root *root = BTRFS_I(dir)->root;
6073         struct inode *inode = NULL;
6074         int drop_inode_on_err = 0;
6075         int err;
6076         u64 objectid;
6077         u64 index = 0;
6078
6079         /*
6080          * 2 for inode item and ref
6081          * 2 for dir items
6082          * 1 for xattr if selinux is on
6083          */
6084         trans = btrfs_start_transaction(root, 5);
6085         if (IS_ERR(trans))
6086                 return PTR_ERR(trans);
6087
6088         err = btrfs_find_free_ino(root, &objectid);
6089         if (err)
6090                 goto out_unlock;
6091
6092         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6093                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6094                                 mode, &index);
6095         if (IS_ERR(inode)) {
6096                 err = PTR_ERR(inode);
6097                 goto out_unlock;
6098         }
6099         drop_inode_on_err = 1;
6100         /*
6101         * If the active LSM wants to access the inode during
6102         * d_instantiate it needs these. Smack checks to see
6103         * if the filesystem supports xattrs by looking at the
6104         * ops vector.
6105         */
6106         inode->i_fop = &btrfs_file_operations;
6107         inode->i_op = &btrfs_file_inode_operations;
6108         inode->i_mapping->a_ops = &btrfs_aops;
6109         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
6110
6111         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6112         if (err)
6113                 goto out_unlock_inode;
6114
6115         err = btrfs_update_inode(trans, root, inode);
6116         if (err)
6117                 goto out_unlock_inode;
6118
6119         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6120         if (err)
6121                 goto out_unlock_inode;
6122
6123         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6124         unlock_new_inode(inode);
6125         d_instantiate(dentry, inode);
6126
6127 out_unlock:
6128         btrfs_end_transaction(trans, root);
6129         if (err && drop_inode_on_err) {
6130                 inode_dec_link_count(inode);
6131                 iput(inode);
6132         }
6133         btrfs_balance_delayed_items(root);
6134         btrfs_btree_balance_dirty(root);
6135         return err;
6136
6137 out_unlock_inode:
6138         unlock_new_inode(inode);
6139         goto out_unlock;
6140
6141 }
6142
6143 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6144                       struct dentry *dentry)
6145 {
6146         struct btrfs_trans_handle *trans;
6147         struct btrfs_root *root = BTRFS_I(dir)->root;
6148         struct inode *inode = old_dentry->d_inode;
6149         u64 index;
6150         int err;
6151         int drop_inode = 0;
6152
6153         /* do not allow sys_link's with other subvols of the same device */
6154         if (root->objectid != BTRFS_I(inode)->root->objectid)
6155                 return -EXDEV;
6156
6157         if (inode->i_nlink >= BTRFS_LINK_MAX)
6158                 return -EMLINK;
6159
6160         err = btrfs_set_inode_index(dir, &index);
6161         if (err)
6162                 goto fail;
6163
6164         /*
6165          * 2 items for inode and inode ref
6166          * 2 items for dir items
6167          * 1 item for parent inode
6168          */
6169         trans = btrfs_start_transaction(root, 5);
6170         if (IS_ERR(trans)) {
6171                 err = PTR_ERR(trans);
6172                 goto fail;
6173         }
6174
6175         /* There are several dir indexes for this inode, clear the cache. */
6176         BTRFS_I(inode)->dir_index = 0ULL;
6177         inc_nlink(inode);
6178         inode_inc_iversion(inode);
6179         inode->i_ctime = CURRENT_TIME;
6180         ihold(inode);
6181         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6182
6183         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6184
6185         if (err) {
6186                 drop_inode = 1;
6187         } else {
6188                 struct dentry *parent = dentry->d_parent;
6189                 err = btrfs_update_inode(trans, root, inode);
6190                 if (err)
6191                         goto fail;
6192                 if (inode->i_nlink == 1) {
6193                         /*
6194                          * If new hard link count is 1, it's a file created
6195                          * with open(2) O_TMPFILE flag.
6196                          */
6197                         err = btrfs_orphan_del(trans, inode);
6198                         if (err)
6199                                 goto fail;
6200                 }
6201                 d_instantiate(dentry, inode);
6202                 btrfs_log_new_name(trans, inode, NULL, parent);
6203         }
6204
6205         btrfs_end_transaction(trans, root);
6206         btrfs_balance_delayed_items(root);
6207 fail:
6208         if (drop_inode) {
6209                 inode_dec_link_count(inode);
6210                 iput(inode);
6211         }
6212         btrfs_btree_balance_dirty(root);
6213         return err;
6214 }
6215
6216 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6217 {
6218         struct inode *inode = NULL;
6219         struct btrfs_trans_handle *trans;
6220         struct btrfs_root *root = BTRFS_I(dir)->root;
6221         int err = 0;
6222         int drop_on_err = 0;
6223         u64 objectid = 0;
6224         u64 index = 0;
6225
6226         /*
6227          * 2 items for inode and ref
6228          * 2 items for dir items
6229          * 1 for xattr if selinux is on
6230          */
6231         trans = btrfs_start_transaction(root, 5);
6232         if (IS_ERR(trans))
6233                 return PTR_ERR(trans);
6234
6235         err = btrfs_find_free_ino(root, &objectid);
6236         if (err)
6237                 goto out_fail;
6238
6239         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6240                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6241                                 S_IFDIR | mode, &index);
6242         if (IS_ERR(inode)) {
6243                 err = PTR_ERR(inode);
6244                 goto out_fail;
6245         }
6246
6247         drop_on_err = 1;
6248         /* these must be set before we unlock the inode */
6249         inode->i_op = &btrfs_dir_inode_operations;
6250         inode->i_fop = &btrfs_dir_file_operations;
6251
6252         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6253         if (err)
6254                 goto out_fail_inode;
6255
6256         btrfs_i_size_write(inode, 0);
6257         err = btrfs_update_inode(trans, root, inode);
6258         if (err)
6259                 goto out_fail_inode;
6260
6261         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6262                              dentry->d_name.len, 0, index);
6263         if (err)
6264                 goto out_fail_inode;
6265
6266         d_instantiate(dentry, inode);
6267         /*
6268          * mkdir is special.  We're unlocking after we call d_instantiate
6269          * to avoid a race with nfsd calling d_instantiate.
6270          */
6271         unlock_new_inode(inode);
6272         drop_on_err = 0;
6273
6274 out_fail:
6275         btrfs_end_transaction(trans, root);
6276         if (drop_on_err) {
6277                 inode_dec_link_count(inode);
6278                 iput(inode);
6279         }
6280         btrfs_balance_delayed_items(root);
6281         btrfs_btree_balance_dirty(root);
6282         return err;
6283
6284 out_fail_inode:
6285         unlock_new_inode(inode);
6286         goto out_fail;
6287 }
6288
6289 /* Find next extent map of a given extent map, caller needs to ensure locks */
6290 static struct extent_map *next_extent_map(struct extent_map *em)
6291 {
6292         struct rb_node *next;
6293
6294         next = rb_next(&em->rb_node);
6295         if (!next)
6296                 return NULL;
6297         return container_of(next, struct extent_map, rb_node);
6298 }
6299
6300 static struct extent_map *prev_extent_map(struct extent_map *em)
6301 {
6302         struct rb_node *prev;
6303
6304         prev = rb_prev(&em->rb_node);
6305         if (!prev)
6306                 return NULL;
6307         return container_of(prev, struct extent_map, rb_node);
6308 }
6309
6310 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6311  * the existing extent is the nearest extent to map_start,
6312  * and an extent that you want to insert, deal with overlap and insert
6313  * the best fitted new extent into the tree.
6314  */
6315 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6316                                 struct extent_map *existing,
6317                                 struct extent_map *em,
6318                                 u64 map_start)
6319 {
6320         struct extent_map *prev;
6321         struct extent_map *next;
6322         u64 start;
6323         u64 end;
6324         u64 start_diff;
6325
6326         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6327
6328         if (existing->start > map_start) {
6329                 next = existing;
6330                 prev = prev_extent_map(next);
6331         } else {
6332                 prev = existing;
6333                 next = next_extent_map(prev);
6334         }
6335
6336         start = prev ? extent_map_end(prev) : em->start;
6337         start = max_t(u64, start, em->start);
6338         end = next ? next->start : extent_map_end(em);
6339         end = min_t(u64, end, extent_map_end(em));
6340         start_diff = start - em->start;
6341         em->start = start;
6342         em->len = end - start;
6343         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6344             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6345                 em->block_start += start_diff;
6346                 em->block_len -= start_diff;
6347         }
6348         return add_extent_mapping(em_tree, em, 0);
6349 }
6350
6351 static noinline int uncompress_inline(struct btrfs_path *path,
6352                                       struct inode *inode, struct page *page,
6353                                       size_t pg_offset, u64 extent_offset,
6354                                       struct btrfs_file_extent_item *item)
6355 {
6356         int ret;
6357         struct extent_buffer *leaf = path->nodes[0];
6358         char *tmp;
6359         size_t max_size;
6360         unsigned long inline_size;
6361         unsigned long ptr;
6362         int compress_type;
6363
6364         WARN_ON(pg_offset != 0);
6365         compress_type = btrfs_file_extent_compression(leaf, item);
6366         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6367         inline_size = btrfs_file_extent_inline_item_len(leaf,
6368                                         btrfs_item_nr(path->slots[0]));
6369         tmp = kmalloc(inline_size, GFP_NOFS);
6370         if (!tmp)
6371                 return -ENOMEM;
6372         ptr = btrfs_file_extent_inline_start(item);
6373
6374         read_extent_buffer(leaf, tmp, ptr, inline_size);
6375
6376         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6377         ret = btrfs_decompress(compress_type, tmp, page,
6378                                extent_offset, inline_size, max_size);
6379         kfree(tmp);
6380         return ret;
6381 }
6382
6383 /*
6384  * a bit scary, this does extent mapping from logical file offset to the disk.
6385  * the ugly parts come from merging extents from the disk with the in-ram
6386  * representation.  This gets more complex because of the data=ordered code,
6387  * where the in-ram extents might be locked pending data=ordered completion.
6388  *
6389  * This also copies inline extents directly into the page.
6390  */
6391
6392 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6393                                     size_t pg_offset, u64 start, u64 len,
6394                                     int create)
6395 {
6396         int ret;
6397         int err = 0;
6398         u64 extent_start = 0;
6399         u64 extent_end = 0;
6400         u64 objectid = btrfs_ino(inode);
6401         u32 found_type;
6402         struct btrfs_path *path = NULL;
6403         struct btrfs_root *root = BTRFS_I(inode)->root;
6404         struct btrfs_file_extent_item *item;
6405         struct extent_buffer *leaf;
6406         struct btrfs_key found_key;
6407         struct extent_map *em = NULL;
6408         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6409         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6410         struct btrfs_trans_handle *trans = NULL;
6411         const bool new_inline = !page || create;
6412
6413 again:
6414         read_lock(&em_tree->lock);
6415         em = lookup_extent_mapping(em_tree, start, len);
6416         if (em)
6417                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6418         read_unlock(&em_tree->lock);
6419
6420         if (em) {
6421                 if (em->start > start || em->start + em->len <= start)
6422                         free_extent_map(em);
6423                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6424                         free_extent_map(em);
6425                 else
6426                         goto out;
6427         }
6428         em = alloc_extent_map();
6429         if (!em) {
6430                 err = -ENOMEM;
6431                 goto out;
6432         }
6433         em->bdev = root->fs_info->fs_devices->latest_bdev;
6434         em->start = EXTENT_MAP_HOLE;
6435         em->orig_start = EXTENT_MAP_HOLE;
6436         em->len = (u64)-1;
6437         em->block_len = (u64)-1;
6438
6439         if (!path) {
6440                 path = btrfs_alloc_path();
6441                 if (!path) {
6442                         err = -ENOMEM;
6443                         goto out;
6444                 }
6445                 /*
6446                  * Chances are we'll be called again, so go ahead and do
6447                  * readahead
6448                  */
6449                 path->reada = 1;
6450         }
6451
6452         ret = btrfs_lookup_file_extent(trans, root, path,
6453                                        objectid, start, trans != NULL);
6454         if (ret < 0) {
6455                 err = ret;
6456                 goto out;
6457         }
6458
6459         if (ret != 0) {
6460                 if (path->slots[0] == 0)
6461                         goto not_found;
6462                 path->slots[0]--;
6463         }
6464
6465         leaf = path->nodes[0];
6466         item = btrfs_item_ptr(leaf, path->slots[0],
6467                               struct btrfs_file_extent_item);
6468         /* are we inside the extent that was found? */
6469         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6470         found_type = found_key.type;
6471         if (found_key.objectid != objectid ||
6472             found_type != BTRFS_EXTENT_DATA_KEY) {
6473                 /*
6474                  * If we backup past the first extent we want to move forward
6475                  * and see if there is an extent in front of us, otherwise we'll
6476                  * say there is a hole for our whole search range which can
6477                  * cause problems.
6478                  */
6479                 extent_end = start;
6480                 goto next;
6481         }
6482
6483         found_type = btrfs_file_extent_type(leaf, item);
6484         extent_start = found_key.offset;
6485         if (found_type == BTRFS_FILE_EXTENT_REG ||
6486             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6487                 extent_end = extent_start +
6488                        btrfs_file_extent_num_bytes(leaf, item);
6489         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6490                 size_t size;
6491                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6492                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6493         }
6494 next:
6495         if (start >= extent_end) {
6496                 path->slots[0]++;
6497                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6498                         ret = btrfs_next_leaf(root, path);
6499                         if (ret < 0) {
6500                                 err = ret;
6501                                 goto out;
6502                         }
6503                         if (ret > 0)
6504                                 goto not_found;
6505                         leaf = path->nodes[0];
6506                 }
6507                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6508                 if (found_key.objectid != objectid ||
6509                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6510                         goto not_found;
6511                 if (start + len <= found_key.offset)
6512                         goto not_found;
6513                 if (start > found_key.offset)
6514                         goto next;
6515                 em->start = start;
6516                 em->orig_start = start;
6517                 em->len = found_key.offset - start;
6518                 goto not_found_em;
6519         }
6520
6521         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6522
6523         if (found_type == BTRFS_FILE_EXTENT_REG ||
6524             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6525                 goto insert;
6526         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6527                 unsigned long ptr;
6528                 char *map;
6529                 size_t size;
6530                 size_t extent_offset;
6531                 size_t copy_size;
6532
6533                 if (new_inline)
6534                         goto out;
6535
6536                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6537                 extent_offset = page_offset(page) + pg_offset - extent_start;
6538                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6539                                 size - extent_offset);
6540                 em->start = extent_start + extent_offset;
6541                 em->len = ALIGN(copy_size, root->sectorsize);
6542                 em->orig_block_len = em->len;
6543                 em->orig_start = em->start;
6544                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6545                 if (create == 0 && !PageUptodate(page)) {
6546                         if (btrfs_file_extent_compression(leaf, item) !=
6547                             BTRFS_COMPRESS_NONE) {
6548                                 ret = uncompress_inline(path, inode, page,
6549                                                         pg_offset,
6550                                                         extent_offset, item);
6551                                 if (ret) {
6552                                         err = ret;
6553                                         goto out;
6554                                 }
6555                         } else {
6556                                 map = kmap(page);
6557                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6558                                                    copy_size);
6559                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6560                                         memset(map + pg_offset + copy_size, 0,
6561                                                PAGE_CACHE_SIZE - pg_offset -
6562                                                copy_size);
6563                                 }
6564                                 kunmap(page);
6565                         }
6566                         flush_dcache_page(page);
6567                 } else if (create && PageUptodate(page)) {
6568                         BUG();
6569                         if (!trans) {
6570                                 kunmap(page);
6571                                 free_extent_map(em);
6572                                 em = NULL;
6573
6574                                 btrfs_release_path(path);
6575                                 trans = btrfs_join_transaction(root);
6576
6577                                 if (IS_ERR(trans))
6578                                         return ERR_CAST(trans);
6579                                 goto again;
6580                         }
6581                         map = kmap(page);
6582                         write_extent_buffer(leaf, map + pg_offset, ptr,
6583                                             copy_size);
6584                         kunmap(page);
6585                         btrfs_mark_buffer_dirty(leaf);
6586                 }
6587                 set_extent_uptodate(io_tree, em->start,
6588                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6589                 goto insert;
6590         }
6591 not_found:
6592         em->start = start;
6593         em->orig_start = start;
6594         em->len = len;
6595 not_found_em:
6596         em->block_start = EXTENT_MAP_HOLE;
6597         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6598 insert:
6599         btrfs_release_path(path);
6600         if (em->start > start || extent_map_end(em) <= start) {
6601                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6602                         em->start, em->len, start, len);
6603                 err = -EIO;
6604                 goto out;
6605         }
6606
6607         err = 0;
6608         write_lock(&em_tree->lock);
6609         ret = add_extent_mapping(em_tree, em, 0);
6610         /* it is possible that someone inserted the extent into the tree
6611          * while we had the lock dropped.  It is also possible that
6612          * an overlapping map exists in the tree
6613          */
6614         if (ret == -EEXIST) {
6615                 struct extent_map *existing;
6616
6617                 ret = 0;
6618
6619                 existing = search_extent_mapping(em_tree, start, len);
6620                 /*
6621                  * existing will always be non-NULL, since there must be
6622                  * extent causing the -EEXIST.
6623                  */
6624                 if (start >= extent_map_end(existing) ||
6625                     start <= existing->start) {
6626                         /*
6627                          * The existing extent map is the one nearest to
6628                          * the [start, start + len) range which overlaps
6629                          */
6630                         err = merge_extent_mapping(em_tree, existing,
6631                                                    em, start);
6632                         free_extent_map(existing);
6633                         if (err) {
6634                                 free_extent_map(em);
6635                                 em = NULL;
6636                         }
6637                 } else {
6638                         free_extent_map(em);
6639                         em = existing;
6640                         err = 0;
6641                 }
6642         }
6643         write_unlock(&em_tree->lock);
6644 out:
6645
6646         trace_btrfs_get_extent(root, em);
6647
6648         if (path)
6649                 btrfs_free_path(path);
6650         if (trans) {
6651                 ret = btrfs_end_transaction(trans, root);
6652                 if (!err)
6653                         err = ret;
6654         }
6655         if (err) {
6656                 free_extent_map(em);
6657                 return ERR_PTR(err);
6658         }
6659         BUG_ON(!em); /* Error is always set */
6660         return em;
6661 }
6662
6663 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6664                                            size_t pg_offset, u64 start, u64 len,
6665                                            int create)
6666 {
6667         struct extent_map *em;
6668         struct extent_map *hole_em = NULL;
6669         u64 range_start = start;
6670         u64 end;
6671         u64 found;
6672         u64 found_end;
6673         int err = 0;
6674
6675         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6676         if (IS_ERR(em))
6677                 return em;
6678         if (em) {
6679                 /*
6680                  * if our em maps to
6681                  * -  a hole or
6682                  * -  a pre-alloc extent,
6683                  * there might actually be delalloc bytes behind it.
6684                  */
6685                 if (em->block_start != EXTENT_MAP_HOLE &&
6686                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6687                         return em;
6688                 else
6689                         hole_em = em;
6690         }
6691
6692         /* check to see if we've wrapped (len == -1 or similar) */
6693         end = start + len;
6694         if (end < start)
6695                 end = (u64)-1;
6696         else
6697                 end -= 1;
6698
6699         em = NULL;
6700
6701         /* ok, we didn't find anything, lets look for delalloc */
6702         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6703                                  end, len, EXTENT_DELALLOC, 1);
6704         found_end = range_start + found;
6705         if (found_end < range_start)
6706                 found_end = (u64)-1;
6707
6708         /*
6709          * we didn't find anything useful, return
6710          * the original results from get_extent()
6711          */
6712         if (range_start > end || found_end <= start) {
6713                 em = hole_em;
6714                 hole_em = NULL;
6715                 goto out;
6716         }
6717
6718         /* adjust the range_start to make sure it doesn't
6719          * go backwards from the start they passed in
6720          */
6721         range_start = max(start, range_start);
6722         found = found_end - range_start;
6723
6724         if (found > 0) {
6725                 u64 hole_start = start;
6726                 u64 hole_len = len;
6727
6728                 em = alloc_extent_map();
6729                 if (!em) {
6730                         err = -ENOMEM;
6731                         goto out;
6732                 }
6733                 /*
6734                  * when btrfs_get_extent can't find anything it
6735                  * returns one huge hole
6736                  *
6737                  * make sure what it found really fits our range, and
6738                  * adjust to make sure it is based on the start from
6739                  * the caller
6740                  */
6741                 if (hole_em) {
6742                         u64 calc_end = extent_map_end(hole_em);
6743
6744                         if (calc_end <= start || (hole_em->start > end)) {
6745                                 free_extent_map(hole_em);
6746                                 hole_em = NULL;
6747                         } else {
6748                                 hole_start = max(hole_em->start, start);
6749                                 hole_len = calc_end - hole_start;
6750                         }
6751                 }
6752                 em->bdev = NULL;
6753                 if (hole_em && range_start > hole_start) {
6754                         /* our hole starts before our delalloc, so we
6755                          * have to return just the parts of the hole
6756                          * that go until  the delalloc starts
6757                          */
6758                         em->len = min(hole_len,
6759                                       range_start - hole_start);
6760                         em->start = hole_start;
6761                         em->orig_start = hole_start;
6762                         /*
6763                          * don't adjust block start at all,
6764                          * it is fixed at EXTENT_MAP_HOLE
6765                          */
6766                         em->block_start = hole_em->block_start;
6767                         em->block_len = hole_len;
6768                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6769                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6770                 } else {
6771                         em->start = range_start;
6772                         em->len = found;
6773                         em->orig_start = range_start;
6774                         em->block_start = EXTENT_MAP_DELALLOC;
6775                         em->block_len = found;
6776                 }
6777         } else if (hole_em) {
6778                 return hole_em;
6779         }
6780 out:
6781
6782         free_extent_map(hole_em);
6783         if (err) {
6784                 free_extent_map(em);
6785                 return ERR_PTR(err);
6786         }
6787         return em;
6788 }
6789
6790 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6791                                                   u64 start, u64 len)
6792 {
6793         struct btrfs_root *root = BTRFS_I(inode)->root;
6794         struct extent_map *em;
6795         struct btrfs_key ins;
6796         u64 alloc_hint;
6797         int ret;
6798
6799         alloc_hint = get_extent_allocation_hint(inode, start, len);
6800         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6801                                    alloc_hint, &ins, 1, 1);
6802         if (ret)
6803                 return ERR_PTR(ret);
6804
6805         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6806                               ins.offset, ins.offset, ins.offset, 0);
6807         if (IS_ERR(em)) {
6808                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6809                 return em;
6810         }
6811
6812         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6813                                            ins.offset, ins.offset, 0);
6814         if (ret) {
6815                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6816                 free_extent_map(em);
6817                 return ERR_PTR(ret);
6818         }
6819
6820         return em;
6821 }
6822
6823 /*
6824  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6825  * block must be cow'd
6826  */
6827 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6828                               u64 *orig_start, u64 *orig_block_len,
6829                               u64 *ram_bytes)
6830 {
6831         struct btrfs_trans_handle *trans;
6832         struct btrfs_path *path;
6833         int ret;
6834         struct extent_buffer *leaf;
6835         struct btrfs_root *root = BTRFS_I(inode)->root;
6836         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6837         struct btrfs_file_extent_item *fi;
6838         struct btrfs_key key;
6839         u64 disk_bytenr;
6840         u64 backref_offset;
6841         u64 extent_end;
6842         u64 num_bytes;
6843         int slot;
6844         int found_type;
6845         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6846
6847         path = btrfs_alloc_path();
6848         if (!path)
6849                 return -ENOMEM;
6850
6851         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6852                                        offset, 0);
6853         if (ret < 0)
6854                 goto out;
6855
6856         slot = path->slots[0];
6857         if (ret == 1) {
6858                 if (slot == 0) {
6859                         /* can't find the item, must cow */
6860                         ret = 0;
6861                         goto out;
6862                 }
6863                 slot--;
6864         }
6865         ret = 0;
6866         leaf = path->nodes[0];
6867         btrfs_item_key_to_cpu(leaf, &key, slot);
6868         if (key.objectid != btrfs_ino(inode) ||
6869             key.type != BTRFS_EXTENT_DATA_KEY) {
6870                 /* not our file or wrong item type, must cow */
6871                 goto out;
6872         }
6873
6874         if (key.offset > offset) {
6875                 /* Wrong offset, must cow */
6876                 goto out;
6877         }
6878
6879         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6880         found_type = btrfs_file_extent_type(leaf, fi);
6881         if (found_type != BTRFS_FILE_EXTENT_REG &&
6882             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6883                 /* not a regular extent, must cow */
6884                 goto out;
6885         }
6886
6887         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6888                 goto out;
6889
6890         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6891         if (extent_end <= offset)
6892                 goto out;
6893
6894         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6895         if (disk_bytenr == 0)
6896                 goto out;
6897
6898         if (btrfs_file_extent_compression(leaf, fi) ||
6899             btrfs_file_extent_encryption(leaf, fi) ||
6900             btrfs_file_extent_other_encoding(leaf, fi))
6901                 goto out;
6902
6903         backref_offset = btrfs_file_extent_offset(leaf, fi);
6904
6905         if (orig_start) {
6906                 *orig_start = key.offset - backref_offset;
6907                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6908                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6909         }
6910
6911         if (btrfs_extent_readonly(root, disk_bytenr))
6912                 goto out;
6913
6914         num_bytes = min(offset + *len, extent_end) - offset;
6915         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6916                 u64 range_end;
6917
6918                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
6919                 ret = test_range_bit(io_tree, offset, range_end,
6920                                      EXTENT_DELALLOC, 0, NULL);
6921                 if (ret) {
6922                         ret = -EAGAIN;
6923                         goto out;
6924                 }
6925         }
6926
6927         btrfs_release_path(path);
6928
6929         /*
6930          * look for other files referencing this extent, if we
6931          * find any we must cow
6932          */
6933         trans = btrfs_join_transaction(root);
6934         if (IS_ERR(trans)) {
6935                 ret = 0;
6936                 goto out;
6937         }
6938
6939         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6940                                     key.offset - backref_offset, disk_bytenr);
6941         btrfs_end_transaction(trans, root);
6942         if (ret) {
6943                 ret = 0;
6944                 goto out;
6945         }
6946
6947         /*
6948          * adjust disk_bytenr and num_bytes to cover just the bytes
6949          * in this extent we are about to write.  If there
6950          * are any csums in that range we have to cow in order
6951          * to keep the csums correct
6952          */
6953         disk_bytenr += backref_offset;
6954         disk_bytenr += offset - key.offset;
6955         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6956                                 goto out;
6957         /*
6958          * all of the above have passed, it is safe to overwrite this extent
6959          * without cow
6960          */
6961         *len = num_bytes;
6962         ret = 1;
6963 out:
6964         btrfs_free_path(path);
6965         return ret;
6966 }
6967
6968 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
6969 {
6970         struct radix_tree_root *root = &inode->i_mapping->page_tree;
6971         int found = false;
6972         void **pagep = NULL;
6973         struct page *page = NULL;
6974         int start_idx;
6975         int end_idx;
6976
6977         start_idx = start >> PAGE_CACHE_SHIFT;
6978
6979         /*
6980          * end is the last byte in the last page.  end == start is legal
6981          */
6982         end_idx = end >> PAGE_CACHE_SHIFT;
6983
6984         rcu_read_lock();
6985
6986         /* Most of the code in this while loop is lifted from
6987          * find_get_page.  It's been modified to begin searching from a
6988          * page and return just the first page found in that range.  If the
6989          * found idx is less than or equal to the end idx then we know that
6990          * a page exists.  If no pages are found or if those pages are
6991          * outside of the range then we're fine (yay!) */
6992         while (page == NULL &&
6993                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
6994                 page = radix_tree_deref_slot(pagep);
6995                 if (unlikely(!page))
6996                         break;
6997
6998                 if (radix_tree_exception(page)) {
6999                         if (radix_tree_deref_retry(page)) {
7000                                 page = NULL;
7001                                 continue;
7002                         }
7003                         /*
7004                          * Otherwise, shmem/tmpfs must be storing a swap entry
7005                          * here as an exceptional entry: so return it without
7006                          * attempting to raise page count.
7007                          */
7008                         page = NULL;
7009                         break; /* TODO: Is this relevant for this use case? */
7010                 }
7011
7012                 if (!page_cache_get_speculative(page)) {
7013                         page = NULL;
7014                         continue;
7015                 }
7016
7017                 /*
7018                  * Has the page moved?
7019                  * This is part of the lockless pagecache protocol. See
7020                  * include/linux/pagemap.h for details.
7021                  */
7022                 if (unlikely(page != *pagep)) {
7023                         page_cache_release(page);
7024                         page = NULL;
7025                 }
7026         }
7027
7028         if (page) {
7029                 if (page->index <= end_idx)
7030                         found = true;
7031                 page_cache_release(page);
7032         }
7033
7034         rcu_read_unlock();
7035         return found;
7036 }
7037
7038 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7039                               struct extent_state **cached_state, int writing)
7040 {
7041         struct btrfs_ordered_extent *ordered;
7042         int ret = 0;
7043
7044         while (1) {
7045                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7046                                  0, cached_state);
7047                 /*
7048                  * We're concerned with the entire range that we're going to be
7049                  * doing DIO to, so we need to make sure theres no ordered
7050                  * extents in this range.
7051                  */
7052                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
7053                                                      lockend - lockstart + 1);
7054
7055                 /*
7056                  * We need to make sure there are no buffered pages in this
7057                  * range either, we could have raced between the invalidate in
7058                  * generic_file_direct_write and locking the extent.  The
7059                  * invalidate needs to happen so that reads after a write do not
7060                  * get stale data.
7061                  */
7062                 if (!ordered &&
7063                     (!writing ||
7064                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7065                         break;
7066
7067                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7068                                      cached_state, GFP_NOFS);
7069
7070                 if (ordered) {
7071                         btrfs_start_ordered_extent(inode, ordered, 1);
7072                         btrfs_put_ordered_extent(ordered);
7073                 } else {
7074                         /* Screw you mmap */
7075                         ret = btrfs_fdatawrite_range(inode, lockstart, lockend);
7076                         if (ret)
7077                                 break;
7078                         ret = filemap_fdatawait_range(inode->i_mapping,
7079                                                       lockstart,
7080                                                       lockend);
7081                         if (ret)
7082                                 break;
7083
7084                         /*
7085                          * If we found a page that couldn't be invalidated just
7086                          * fall back to buffered.
7087                          */
7088                         ret = invalidate_inode_pages2_range(inode->i_mapping,
7089                                         lockstart >> PAGE_CACHE_SHIFT,
7090                                         lockend >> PAGE_CACHE_SHIFT);
7091                         if (ret)
7092                                 break;
7093                 }
7094
7095                 cond_resched();
7096         }
7097
7098         return ret;
7099 }
7100
7101 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
7102                                            u64 len, u64 orig_start,
7103                                            u64 block_start, u64 block_len,
7104                                            u64 orig_block_len, u64 ram_bytes,
7105                                            int type)
7106 {
7107         struct extent_map_tree *em_tree;
7108         struct extent_map *em;
7109         struct btrfs_root *root = BTRFS_I(inode)->root;
7110         int ret;
7111
7112         em_tree = &BTRFS_I(inode)->extent_tree;
7113         em = alloc_extent_map();
7114         if (!em)
7115                 return ERR_PTR(-ENOMEM);
7116
7117         em->start = start;
7118         em->orig_start = orig_start;
7119         em->mod_start = start;
7120         em->mod_len = len;
7121         em->len = len;
7122         em->block_len = block_len;
7123         em->block_start = block_start;
7124         em->bdev = root->fs_info->fs_devices->latest_bdev;
7125         em->orig_block_len = orig_block_len;
7126         em->ram_bytes = ram_bytes;
7127         em->generation = -1;
7128         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7129         if (type == BTRFS_ORDERED_PREALLOC)
7130                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7131
7132         do {
7133                 btrfs_drop_extent_cache(inode, em->start,
7134                                 em->start + em->len - 1, 0);
7135                 write_lock(&em_tree->lock);
7136                 ret = add_extent_mapping(em_tree, em, 1);
7137                 write_unlock(&em_tree->lock);
7138         } while (ret == -EEXIST);
7139
7140         if (ret) {
7141                 free_extent_map(em);
7142                 return ERR_PTR(ret);
7143         }
7144
7145         return em;
7146 }
7147
7148
7149 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7150                                    struct buffer_head *bh_result, int create)
7151 {
7152         struct extent_map *em;
7153         struct btrfs_root *root = BTRFS_I(inode)->root;
7154         struct extent_state *cached_state = NULL;
7155         u64 start = iblock << inode->i_blkbits;
7156         u64 lockstart, lockend;
7157         u64 len = bh_result->b_size;
7158         u64 orig_len = len;
7159         int unlock_bits = EXTENT_LOCKED;
7160         int ret = 0;
7161
7162         if (create)
7163                 unlock_bits |= EXTENT_DIRTY;
7164         else
7165                 len = min_t(u64, len, root->sectorsize);
7166
7167         lockstart = start;
7168         lockend = start + len - 1;
7169
7170         /*
7171          * If this errors out it's because we couldn't invalidate pagecache for
7172          * this range and we need to fallback to buffered.
7173          */
7174         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
7175                 return -ENOTBLK;
7176
7177         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7178         if (IS_ERR(em)) {
7179                 ret = PTR_ERR(em);
7180                 goto unlock_err;
7181         }
7182
7183         /*
7184          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7185          * io.  INLINE is special, and we could probably kludge it in here, but
7186          * it's still buffered so for safety lets just fall back to the generic
7187          * buffered path.
7188          *
7189          * For COMPRESSED we _have_ to read the entire extent in so we can
7190          * decompress it, so there will be buffering required no matter what we
7191          * do, so go ahead and fallback to buffered.
7192          *
7193          * We return -ENOTBLK because thats what makes DIO go ahead and go back
7194          * to buffered IO.  Don't blame me, this is the price we pay for using
7195          * the generic code.
7196          */
7197         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7198             em->block_start == EXTENT_MAP_INLINE) {
7199                 free_extent_map(em);
7200                 ret = -ENOTBLK;
7201                 goto unlock_err;
7202         }
7203
7204         /* Just a good old fashioned hole, return */
7205         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7206                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7207                 free_extent_map(em);
7208                 goto unlock_err;
7209         }
7210
7211         /*
7212          * We don't allocate a new extent in the following cases
7213          *
7214          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7215          * existing extent.
7216          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7217          * just use the extent.
7218          *
7219          */
7220         if (!create) {
7221                 len = min(len, em->len - (start - em->start));
7222                 lockstart = start + len;
7223                 goto unlock;
7224         }
7225
7226         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7227             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7228              em->block_start != EXTENT_MAP_HOLE)) {
7229                 int type;
7230                 int ret;
7231                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7232
7233                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7234                         type = BTRFS_ORDERED_PREALLOC;
7235                 else
7236                         type = BTRFS_ORDERED_NOCOW;
7237                 len = min(len, em->len - (start - em->start));
7238                 block_start = em->block_start + (start - em->start);
7239
7240                 if (can_nocow_extent(inode, start, &len, &orig_start,
7241                                      &orig_block_len, &ram_bytes) == 1) {
7242                         if (type == BTRFS_ORDERED_PREALLOC) {
7243                                 free_extent_map(em);
7244                                 em = create_pinned_em(inode, start, len,
7245                                                        orig_start,
7246                                                        block_start, len,
7247                                                        orig_block_len,
7248                                                        ram_bytes, type);
7249                                 if (IS_ERR(em)) {
7250                                         ret = PTR_ERR(em);
7251                                         goto unlock_err;
7252                                 }
7253                         }
7254
7255                         ret = btrfs_add_ordered_extent_dio(inode, start,
7256                                            block_start, len, len, type);
7257                         if (ret) {
7258                                 free_extent_map(em);
7259                                 goto unlock_err;
7260                         }
7261                         goto unlock;
7262                 }
7263         }
7264
7265         /*
7266          * this will cow the extent, reset the len in case we changed
7267          * it above
7268          */
7269         len = bh_result->b_size;
7270         free_extent_map(em);
7271         em = btrfs_new_extent_direct(inode, start, len);
7272         if (IS_ERR(em)) {
7273                 ret = PTR_ERR(em);
7274                 goto unlock_err;
7275         }
7276         len = min(len, em->len - (start - em->start));
7277 unlock:
7278         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7279                 inode->i_blkbits;
7280         bh_result->b_size = len;
7281         bh_result->b_bdev = em->bdev;
7282         set_buffer_mapped(bh_result);
7283         if (create) {
7284                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7285                         set_buffer_new(bh_result);
7286
7287                 /*
7288                  * Need to update the i_size under the extent lock so buffered
7289                  * readers will get the updated i_size when we unlock.
7290                  */
7291                 if (start + len > i_size_read(inode))
7292                         i_size_write(inode, start + len);
7293
7294                 if (len < orig_len) {
7295                         spin_lock(&BTRFS_I(inode)->lock);
7296                         BTRFS_I(inode)->outstanding_extents++;
7297                         spin_unlock(&BTRFS_I(inode)->lock);
7298                 }
7299                 btrfs_free_reserved_data_space(inode, len);
7300         }
7301
7302         /*
7303          * In the case of write we need to clear and unlock the entire range,
7304          * in the case of read we need to unlock only the end area that we
7305          * aren't using if there is any left over space.
7306          */
7307         if (lockstart < lockend) {
7308                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7309                                  lockend, unlock_bits, 1, 0,
7310                                  &cached_state, GFP_NOFS);
7311         } else {
7312                 free_extent_state(cached_state);
7313         }
7314
7315         free_extent_map(em);
7316
7317         return 0;
7318
7319 unlock_err:
7320         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7321                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7322         return ret;
7323 }
7324
7325 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7326                                         int rw, int mirror_num)
7327 {
7328         struct btrfs_root *root = BTRFS_I(inode)->root;
7329         int ret;
7330
7331         BUG_ON(rw & REQ_WRITE);
7332
7333         bio_get(bio);
7334
7335         ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7336                                   BTRFS_WQ_ENDIO_DIO_REPAIR);
7337         if (ret)
7338                 goto err;
7339
7340         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
7341 err:
7342         bio_put(bio);
7343         return ret;
7344 }
7345
7346 static int btrfs_check_dio_repairable(struct inode *inode,
7347                                       struct bio *failed_bio,
7348                                       struct io_failure_record *failrec,
7349                                       int failed_mirror)
7350 {
7351         int num_copies;
7352
7353         num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
7354                                       failrec->logical, failrec->len);
7355         if (num_copies == 1) {
7356                 /*
7357                  * we only have a single copy of the data, so don't bother with
7358                  * all the retry and error correction code that follows. no
7359                  * matter what the error is, it is very likely to persist.
7360                  */
7361                 pr_debug("Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
7362                          num_copies, failrec->this_mirror, failed_mirror);
7363                 return 0;
7364         }
7365
7366         failrec->failed_mirror = failed_mirror;
7367         failrec->this_mirror++;
7368         if (failrec->this_mirror == failed_mirror)
7369                 failrec->this_mirror++;
7370
7371         if (failrec->this_mirror > num_copies) {
7372                 pr_debug("Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
7373                          num_copies, failrec->this_mirror, failed_mirror);
7374                 return 0;
7375         }
7376
7377         return 1;
7378 }
7379
7380 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7381                           struct page *page, u64 start, u64 end,
7382                           int failed_mirror, bio_end_io_t *repair_endio,
7383                           void *repair_arg)
7384 {
7385         struct io_failure_record *failrec;
7386         struct bio *bio;
7387         int isector;
7388         int read_mode;
7389         int ret;
7390
7391         BUG_ON(failed_bio->bi_rw & REQ_WRITE);
7392
7393         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7394         if (ret)
7395                 return ret;
7396
7397         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7398                                          failed_mirror);
7399         if (!ret) {
7400                 free_io_failure(inode, failrec);
7401                 return -EIO;
7402         }
7403
7404         if (failed_bio->bi_vcnt > 1)
7405                 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
7406         else
7407                 read_mode = READ_SYNC;
7408
7409         isector = start - btrfs_io_bio(failed_bio)->logical;
7410         isector >>= inode->i_sb->s_blocksize_bits;
7411         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7412                                       0, isector, repair_endio, repair_arg);
7413         if (!bio) {
7414                 free_io_failure(inode, failrec);
7415                 return -EIO;
7416         }
7417
7418         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7419                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7420                     read_mode, failrec->this_mirror, failrec->in_validation);
7421
7422         ret = submit_dio_repair_bio(inode, bio, read_mode,
7423                                     failrec->this_mirror);
7424         if (ret) {
7425                 free_io_failure(inode, failrec);
7426                 bio_put(bio);
7427         }
7428
7429         return ret;
7430 }
7431
7432 struct btrfs_retry_complete {
7433         struct completion done;
7434         struct inode *inode;
7435         u64 start;
7436         int uptodate;
7437 };
7438
7439 static void btrfs_retry_endio_nocsum(struct bio *bio, int err)
7440 {
7441         struct btrfs_retry_complete *done = bio->bi_private;
7442         struct bio_vec *bvec;
7443         int i;
7444
7445         if (err)
7446                 goto end;
7447
7448         done->uptodate = 1;
7449         bio_for_each_segment_all(bvec, bio, i)
7450                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7451 end:
7452         complete(&done->done);
7453         bio_put(bio);
7454 }
7455
7456 static int __btrfs_correct_data_nocsum(struct inode *inode,
7457                                        struct btrfs_io_bio *io_bio)
7458 {
7459         struct bio_vec *bvec;
7460         struct btrfs_retry_complete done;
7461         u64 start;
7462         int i;
7463         int ret;
7464
7465         start = io_bio->logical;
7466         done.inode = inode;
7467
7468         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7469 try_again:
7470                 done.uptodate = 0;
7471                 done.start = start;
7472                 init_completion(&done.done);
7473
7474                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,
7475                                      start + bvec->bv_len - 1,
7476                                      io_bio->mirror_num,
7477                                      btrfs_retry_endio_nocsum, &done);
7478                 if (ret)
7479                         return ret;
7480
7481                 wait_for_completion(&done.done);
7482
7483                 if (!done.uptodate) {
7484                         /* We might have another mirror, so try again */
7485                         goto try_again;
7486                 }
7487
7488                 start += bvec->bv_len;
7489         }
7490
7491         return 0;
7492 }
7493
7494 static void btrfs_retry_endio(struct bio *bio, int err)
7495 {
7496         struct btrfs_retry_complete *done = bio->bi_private;
7497         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7498         struct bio_vec *bvec;
7499         int uptodate;
7500         int ret;
7501         int i;
7502
7503         if (err)
7504                 goto end;
7505
7506         uptodate = 1;
7507         bio_for_each_segment_all(bvec, bio, i) {
7508                 ret = __readpage_endio_check(done->inode, io_bio, i,
7509                                              bvec->bv_page, 0,
7510                                              done->start, bvec->bv_len);
7511                 if (!ret)
7512                         clean_io_failure(done->inode, done->start,
7513                                          bvec->bv_page, 0);
7514                 else
7515                         uptodate = 0;
7516         }
7517
7518         done->uptodate = uptodate;
7519 end:
7520         complete(&done->done);
7521         bio_put(bio);
7522 }
7523
7524 static int __btrfs_subio_endio_read(struct inode *inode,
7525                                     struct btrfs_io_bio *io_bio, int err)
7526 {
7527         struct bio_vec *bvec;
7528         struct btrfs_retry_complete done;
7529         u64 start;
7530         u64 offset = 0;
7531         int i;
7532         int ret;
7533
7534         err = 0;
7535         start = io_bio->logical;
7536         done.inode = inode;
7537
7538         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7539                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
7540                                              0, start, bvec->bv_len);
7541                 if (likely(!ret))
7542                         goto next;
7543 try_again:
7544                 done.uptodate = 0;
7545                 done.start = start;
7546                 init_completion(&done.done);
7547
7548                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,
7549                                      start + bvec->bv_len - 1,
7550                                      io_bio->mirror_num,
7551                                      btrfs_retry_endio, &done);
7552                 if (ret) {
7553                         err = ret;
7554                         goto next;
7555                 }
7556
7557                 wait_for_completion(&done.done);
7558
7559                 if (!done.uptodate) {
7560                         /* We might have another mirror, so try again */
7561                         goto try_again;
7562                 }
7563 next:
7564                 offset += bvec->bv_len;
7565                 start += bvec->bv_len;
7566         }
7567
7568         return err;
7569 }
7570
7571 static int btrfs_subio_endio_read(struct inode *inode,
7572                                   struct btrfs_io_bio *io_bio, int err)
7573 {
7574         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7575
7576         if (skip_csum) {
7577                 if (unlikely(err))
7578                         return __btrfs_correct_data_nocsum(inode, io_bio);
7579                 else
7580                         return 0;
7581         } else {
7582                 return __btrfs_subio_endio_read(inode, io_bio, err);
7583         }
7584 }
7585
7586 static void btrfs_endio_direct_read(struct bio *bio, int err)
7587 {
7588         struct btrfs_dio_private *dip = bio->bi_private;
7589         struct inode *inode = dip->inode;
7590         struct bio *dio_bio;
7591         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7592
7593         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
7594                 err = btrfs_subio_endio_read(inode, io_bio, err);
7595
7596         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7597                       dip->logical_offset + dip->bytes - 1);
7598         dio_bio = dip->dio_bio;
7599
7600         kfree(dip);
7601
7602         /* If we had a csum failure make sure to clear the uptodate flag */
7603         if (err)
7604                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7605         dio_end_io(dio_bio, err);
7606
7607         if (io_bio->end_io)
7608                 io_bio->end_io(io_bio, err);
7609         bio_put(bio);
7610 }
7611
7612 static void btrfs_endio_direct_write(struct bio *bio, int err)
7613 {
7614         struct btrfs_dio_private *dip = bio->bi_private;
7615         struct inode *inode = dip->inode;
7616         struct btrfs_root *root = BTRFS_I(inode)->root;
7617         struct btrfs_ordered_extent *ordered = NULL;
7618         u64 ordered_offset = dip->logical_offset;
7619         u64 ordered_bytes = dip->bytes;
7620         struct bio *dio_bio;
7621         int ret;
7622
7623         if (err)
7624                 goto out_done;
7625 again:
7626         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
7627                                                    &ordered_offset,
7628                                                    ordered_bytes, !err);
7629         if (!ret)
7630                 goto out_test;
7631
7632         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
7633                         finish_ordered_fn, NULL, NULL);
7634         btrfs_queue_work(root->fs_info->endio_write_workers,
7635                          &ordered->work);
7636 out_test:
7637         /*
7638          * our bio might span multiple ordered extents.  If we haven't
7639          * completed the accounting for the whole dio, go back and try again
7640          */
7641         if (ordered_offset < dip->logical_offset + dip->bytes) {
7642                 ordered_bytes = dip->logical_offset + dip->bytes -
7643                         ordered_offset;
7644                 ordered = NULL;
7645                 goto again;
7646         }
7647 out_done:
7648         dio_bio = dip->dio_bio;
7649
7650         kfree(dip);
7651
7652         /* If we had an error make sure to clear the uptodate flag */
7653         if (err)
7654                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7655         dio_end_io(dio_bio, err);
7656         bio_put(bio);
7657 }
7658
7659 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7660                                     struct bio *bio, int mirror_num,
7661                                     unsigned long bio_flags, u64 offset)
7662 {
7663         int ret;
7664         struct btrfs_root *root = BTRFS_I(inode)->root;
7665         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7666         BUG_ON(ret); /* -ENOMEM */
7667         return 0;
7668 }
7669
7670 static void btrfs_end_dio_bio(struct bio *bio, int err)
7671 {
7672         struct btrfs_dio_private *dip = bio->bi_private;
7673
7674         if (err)
7675                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
7676                            "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7677                            btrfs_ino(dip->inode), bio->bi_rw,
7678                            (unsigned long long)bio->bi_iter.bi_sector,
7679                            bio->bi_iter.bi_size, err);
7680
7681         if (dip->subio_endio)
7682                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
7683
7684         if (err) {
7685                 dip->errors = 1;
7686
7687                 /*
7688                  * before atomic variable goto zero, we must make sure
7689                  * dip->errors is perceived to be set.
7690                  */
7691                 smp_mb__before_atomic();
7692         }
7693
7694         /* if there are more bios still pending for this dio, just exit */
7695         if (!atomic_dec_and_test(&dip->pending_bios))
7696                 goto out;
7697
7698         if (dip->errors) {
7699                 bio_io_error(dip->orig_bio);
7700         } else {
7701                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7702                 bio_endio(dip->orig_bio, 0);
7703         }
7704 out:
7705         bio_put(bio);
7706 }
7707
7708 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7709                                        u64 first_sector, gfp_t gfp_flags)
7710 {
7711         int nr_vecs = bio_get_nr_vecs(bdev);
7712         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7713 }
7714
7715 static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,
7716                                                  struct inode *inode,
7717                                                  struct btrfs_dio_private *dip,
7718                                                  struct bio *bio,
7719                                                  u64 file_offset)
7720 {
7721         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7722         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
7723         int ret;
7724
7725         /*
7726          * We load all the csum data we need when we submit
7727          * the first bio to reduce the csum tree search and
7728          * contention.
7729          */
7730         if (dip->logical_offset == file_offset) {
7731                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip->orig_bio,
7732                                                 file_offset);
7733                 if (ret)
7734                         return ret;
7735         }
7736
7737         if (bio == dip->orig_bio)
7738                 return 0;
7739
7740         file_offset -= dip->logical_offset;
7741         file_offset >>= inode->i_sb->s_blocksize_bits;
7742         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
7743
7744         return 0;
7745 }
7746
7747 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7748                                          int rw, u64 file_offset, int skip_sum,
7749                                          int async_submit)
7750 {
7751         struct btrfs_dio_private *dip = bio->bi_private;
7752         int write = rw & REQ_WRITE;
7753         struct btrfs_root *root = BTRFS_I(inode)->root;
7754         int ret;
7755
7756         if (async_submit)
7757                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7758
7759         bio_get(bio);
7760
7761         if (!write) {
7762                 ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7763                                 BTRFS_WQ_ENDIO_DATA);
7764                 if (ret)
7765                         goto err;
7766         }
7767
7768         if (skip_sum)
7769                 goto map;
7770
7771         if (write && async_submit) {
7772                 ret = btrfs_wq_submit_bio(root->fs_info,
7773                                    inode, rw, bio, 0, 0,
7774                                    file_offset,
7775                                    __btrfs_submit_bio_start_direct_io,
7776                                    __btrfs_submit_bio_done);
7777                 goto err;
7778         } else if (write) {
7779                 /*
7780                  * If we aren't doing async submit, calculate the csum of the
7781                  * bio now.
7782                  */
7783                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7784                 if (ret)
7785                         goto err;
7786         } else {
7787                 ret = btrfs_lookup_and_bind_dio_csum(root, inode, dip, bio,
7788                                                      file_offset);
7789                 if (ret)
7790                         goto err;
7791         }
7792 map:
7793         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7794 err:
7795         bio_put(bio);
7796         return ret;
7797 }
7798
7799 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7800                                     int skip_sum)
7801 {
7802         struct inode *inode = dip->inode;
7803         struct btrfs_root *root = BTRFS_I(inode)->root;
7804         struct bio *bio;
7805         struct bio *orig_bio = dip->orig_bio;
7806         struct bio_vec *bvec = orig_bio->bi_io_vec;
7807         u64 start_sector = orig_bio->bi_iter.bi_sector;
7808         u64 file_offset = dip->logical_offset;
7809         u64 submit_len = 0;
7810         u64 map_length;
7811         int nr_pages = 0;
7812         int ret;
7813         int async_submit = 0;
7814
7815         map_length = orig_bio->bi_iter.bi_size;
7816         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7817                               &map_length, NULL, 0);
7818         if (ret)
7819                 return -EIO;
7820
7821         if (map_length >= orig_bio->bi_iter.bi_size) {
7822                 bio = orig_bio;
7823                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
7824                 goto submit;
7825         }
7826
7827         /* async crcs make it difficult to collect full stripe writes. */
7828         if (btrfs_get_alloc_profile(root, 1) & BTRFS_BLOCK_GROUP_RAID56_MASK)
7829                 async_submit = 0;
7830         else
7831                 async_submit = 1;
7832
7833         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7834         if (!bio)
7835                 return -ENOMEM;
7836
7837         bio->bi_private = dip;
7838         bio->bi_end_io = btrfs_end_dio_bio;
7839         btrfs_io_bio(bio)->logical = file_offset;
7840         atomic_inc(&dip->pending_bios);
7841
7842         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7843                 if (map_length < submit_len + bvec->bv_len ||
7844                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7845                                  bvec->bv_offset) < bvec->bv_len) {
7846                         /*
7847                          * inc the count before we submit the bio so
7848                          * we know the end IO handler won't happen before
7849                          * we inc the count. Otherwise, the dip might get freed
7850                          * before we're done setting it up
7851                          */
7852                         atomic_inc(&dip->pending_bios);
7853                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7854                                                      file_offset, skip_sum,
7855                                                      async_submit);
7856                         if (ret) {
7857                                 bio_put(bio);
7858                                 atomic_dec(&dip->pending_bios);
7859                                 goto out_err;
7860                         }
7861
7862                         start_sector += submit_len >> 9;
7863                         file_offset += submit_len;
7864
7865                         submit_len = 0;
7866                         nr_pages = 0;
7867
7868                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7869                                                   start_sector, GFP_NOFS);
7870                         if (!bio)
7871                                 goto out_err;
7872                         bio->bi_private = dip;
7873                         bio->bi_end_io = btrfs_end_dio_bio;
7874                         btrfs_io_bio(bio)->logical = file_offset;
7875
7876                         map_length = orig_bio->bi_iter.bi_size;
7877                         ret = btrfs_map_block(root->fs_info, rw,
7878                                               start_sector << 9,
7879                                               &map_length, NULL, 0);
7880                         if (ret) {
7881                                 bio_put(bio);
7882                                 goto out_err;
7883                         }
7884                 } else {
7885                         submit_len += bvec->bv_len;
7886                         nr_pages++;
7887                         bvec++;
7888                 }
7889         }
7890
7891 submit:
7892         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7893                                      async_submit);
7894         if (!ret)
7895                 return 0;
7896
7897         bio_put(bio);
7898 out_err:
7899         dip->errors = 1;
7900         /*
7901          * before atomic variable goto zero, we must
7902          * make sure dip->errors is perceived to be set.
7903          */
7904         smp_mb__before_atomic();
7905         if (atomic_dec_and_test(&dip->pending_bios))
7906                 bio_io_error(dip->orig_bio);
7907
7908         /* bio_end_io() will handle error, so we needn't return it */
7909         return 0;
7910 }
7911
7912 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7913                                 struct inode *inode, loff_t file_offset)
7914 {
7915         struct btrfs_root *root = BTRFS_I(inode)->root;
7916         struct btrfs_dio_private *dip;
7917         struct bio *io_bio;
7918         struct btrfs_io_bio *btrfs_bio;
7919         int skip_sum;
7920         int write = rw & REQ_WRITE;
7921         int ret = 0;
7922
7923         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7924
7925         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7926         if (!io_bio) {
7927                 ret = -ENOMEM;
7928                 goto free_ordered;
7929         }
7930
7931         dip = kzalloc(sizeof(*dip), GFP_NOFS);
7932         if (!dip) {
7933                 ret = -ENOMEM;
7934                 goto free_io_bio;
7935         }
7936
7937         dip->private = dio_bio->bi_private;
7938         dip->inode = inode;
7939         dip->logical_offset = file_offset;
7940         dip->bytes = dio_bio->bi_iter.bi_size;
7941         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
7942         io_bio->bi_private = dip;
7943         dip->orig_bio = io_bio;
7944         dip->dio_bio = dio_bio;
7945         atomic_set(&dip->pending_bios, 0);
7946         btrfs_bio = btrfs_io_bio(io_bio);
7947         btrfs_bio->logical = file_offset;
7948
7949         if (write) {
7950                 io_bio->bi_end_io = btrfs_endio_direct_write;
7951         } else {
7952                 io_bio->bi_end_io = btrfs_endio_direct_read;
7953                 dip->subio_endio = btrfs_subio_endio_read;
7954         }
7955
7956         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7957         if (!ret)
7958                 return;
7959
7960         if (btrfs_bio->end_io)
7961                 btrfs_bio->end_io(btrfs_bio, ret);
7962 free_io_bio:
7963         bio_put(io_bio);
7964
7965 free_ordered:
7966         /*
7967          * If this is a write, we need to clean up the reserved space and kill
7968          * the ordered extent.
7969          */
7970         if (write) {
7971                 struct btrfs_ordered_extent *ordered;
7972                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7973                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7974                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7975                         btrfs_free_reserved_extent(root, ordered->start,
7976                                                    ordered->disk_len, 1);
7977                 btrfs_put_ordered_extent(ordered);
7978                 btrfs_put_ordered_extent(ordered);
7979         }
7980         bio_endio(dio_bio, ret);
7981 }
7982
7983 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7984                         const struct iov_iter *iter, loff_t offset)
7985 {
7986         int seg;
7987         int i;
7988         unsigned blocksize_mask = root->sectorsize - 1;
7989         ssize_t retval = -EINVAL;
7990
7991         if (offset & blocksize_mask)
7992                 goto out;
7993
7994         if (iov_iter_alignment(iter) & blocksize_mask)
7995                 goto out;
7996
7997         /* If this is a write we don't need to check anymore */
7998         if (rw & WRITE)
7999                 return 0;
8000         /*
8001          * Check to make sure we don't have duplicate iov_base's in this
8002          * iovec, if so return EINVAL, otherwise we'll get csum errors
8003          * when reading back.
8004          */
8005         for (seg = 0; seg < iter->nr_segs; seg++) {
8006                 for (i = seg + 1; i < iter->nr_segs; i++) {
8007                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8008                                 goto out;
8009                 }
8010         }
8011         retval = 0;
8012 out:
8013         return retval;
8014 }
8015
8016 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
8017                         struct iov_iter *iter, loff_t offset)
8018 {
8019         struct file *file = iocb->ki_filp;
8020         struct inode *inode = file->f_mapping->host;
8021         size_t count = 0;
8022         int flags = 0;
8023         bool wakeup = true;
8024         bool relock = false;
8025         ssize_t ret;
8026
8027         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iter, offset))
8028                 return 0;
8029
8030         atomic_inc(&inode->i_dio_count);
8031         smp_mb__after_atomic();
8032
8033         /*
8034          * The generic stuff only does filemap_write_and_wait_range, which
8035          * isn't enough if we've written compressed pages to this area, so
8036          * we need to flush the dirty pages again to make absolutely sure
8037          * that any outstanding dirty pages are on disk.
8038          */
8039         count = iov_iter_count(iter);
8040         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8041                      &BTRFS_I(inode)->runtime_flags))
8042                 filemap_fdatawrite_range(inode->i_mapping, offset,
8043                                          offset + count - 1);
8044
8045         if (rw & WRITE) {
8046                 /*
8047                  * If the write DIO is beyond the EOF, we need update
8048                  * the isize, but it is protected by i_mutex. So we can
8049                  * not unlock the i_mutex at this case.
8050                  */
8051                 if (offset + count <= inode->i_size) {
8052                         mutex_unlock(&inode->i_mutex);
8053                         relock = true;
8054                 }
8055                 ret = btrfs_delalloc_reserve_space(inode, count);
8056                 if (ret)
8057                         goto out;
8058         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8059                                      &BTRFS_I(inode)->runtime_flags)) {
8060                 inode_dio_done(inode);
8061                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8062                 wakeup = false;
8063         }
8064
8065         ret = __blockdev_direct_IO(rw, iocb, inode,
8066                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
8067                         iter, offset, btrfs_get_blocks_direct, NULL,
8068                         btrfs_submit_direct, flags);
8069         if (rw & WRITE) {
8070                 if (ret < 0 && ret != -EIOCBQUEUED)
8071                         btrfs_delalloc_release_space(inode, count);
8072                 else if (ret >= 0 && (size_t)ret < count)
8073                         btrfs_delalloc_release_space(inode,
8074                                                      count - (size_t)ret);
8075         }
8076 out:
8077         if (wakeup)
8078                 inode_dio_done(inode);
8079         if (relock)
8080                 mutex_lock(&inode->i_mutex);
8081
8082         return ret;
8083 }
8084
8085 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8086
8087 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8088                 __u64 start, __u64 len)
8089 {
8090         int     ret;
8091
8092         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8093         if (ret)
8094                 return ret;
8095
8096         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8097 }
8098
8099 int btrfs_readpage(struct file *file, struct page *page)
8100 {
8101         struct extent_io_tree *tree;
8102         tree = &BTRFS_I(page->mapping->host)->io_tree;
8103         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8104 }
8105
8106 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8107 {
8108         struct extent_io_tree *tree;
8109
8110
8111         if (current->flags & PF_MEMALLOC) {
8112                 redirty_page_for_writepage(wbc, page);
8113                 unlock_page(page);
8114                 return 0;
8115         }
8116         tree = &BTRFS_I(page->mapping->host)->io_tree;
8117         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8118 }
8119
8120 static int btrfs_writepages(struct address_space *mapping,
8121                             struct writeback_control *wbc)
8122 {
8123         struct extent_io_tree *tree;
8124
8125         tree = &BTRFS_I(mapping->host)->io_tree;
8126         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8127 }
8128
8129 static int
8130 btrfs_readpages(struct file *file, struct address_space *mapping,
8131                 struct list_head *pages, unsigned nr_pages)
8132 {
8133         struct extent_io_tree *tree;
8134         tree = &BTRFS_I(mapping->host)->io_tree;
8135         return extent_readpages(tree, mapping, pages, nr_pages,
8136                                 btrfs_get_extent);
8137 }
8138 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8139 {
8140         struct extent_io_tree *tree;
8141         struct extent_map_tree *map;
8142         int ret;
8143
8144         tree = &BTRFS_I(page->mapping->host)->io_tree;
8145         map = &BTRFS_I(page->mapping->host)->extent_tree;
8146         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8147         if (ret == 1) {
8148                 ClearPagePrivate(page);
8149                 set_page_private(page, 0);
8150                 page_cache_release(page);
8151         }
8152         return ret;
8153 }
8154
8155 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8156 {
8157         if (PageWriteback(page) || PageDirty(page))
8158                 return 0;
8159         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
8160 }
8161
8162 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8163                                  unsigned int length)
8164 {
8165         struct inode *inode = page->mapping->host;
8166         struct extent_io_tree *tree;
8167         struct btrfs_ordered_extent *ordered;
8168         struct extent_state *cached_state = NULL;
8169         u64 page_start = page_offset(page);
8170         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
8171         int inode_evicting = inode->i_state & I_FREEING;
8172
8173         /*
8174          * we have the page locked, so new writeback can't start,
8175          * and the dirty bit won't be cleared while we are here.
8176          *
8177          * Wait for IO on this page so that we can safely clear
8178          * the PagePrivate2 bit and do ordered accounting
8179          */
8180         wait_on_page_writeback(page);
8181
8182         tree = &BTRFS_I(inode)->io_tree;
8183         if (offset) {
8184                 btrfs_releasepage(page, GFP_NOFS);
8185                 return;
8186         }
8187
8188         if (!inode_evicting)
8189                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
8190         ordered = btrfs_lookup_ordered_extent(inode, page_start);
8191         if (ordered) {
8192                 /*
8193                  * IO on this page will never be started, so we need
8194                  * to account for any ordered extents now
8195                  */
8196                 if (!inode_evicting)
8197                         clear_extent_bit(tree, page_start, page_end,
8198                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8199                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8200                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8201                                          GFP_NOFS);
8202                 /*
8203                  * whoever cleared the private bit is responsible
8204                  * for the finish_ordered_io
8205                  */
8206                 if (TestClearPagePrivate2(page)) {
8207                         struct btrfs_ordered_inode_tree *tree;
8208                         u64 new_len;
8209
8210                         tree = &BTRFS_I(inode)->ordered_tree;
8211
8212                         spin_lock_irq(&tree->lock);
8213                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8214                         new_len = page_start - ordered->file_offset;
8215                         if (new_len < ordered->truncated_len)
8216                                 ordered->truncated_len = new_len;
8217                         spin_unlock_irq(&tree->lock);
8218
8219                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8220                                                            page_start,
8221                                                            PAGE_CACHE_SIZE, 1))
8222                                 btrfs_finish_ordered_io(ordered);
8223                 }
8224                 btrfs_put_ordered_extent(ordered);
8225                 if (!inode_evicting) {
8226                         cached_state = NULL;
8227                         lock_extent_bits(tree, page_start, page_end, 0,
8228                                          &cached_state);
8229                 }
8230         }
8231
8232         if (!inode_evicting) {
8233                 clear_extent_bit(tree, page_start, page_end,
8234                                  EXTENT_LOCKED | EXTENT_DIRTY |
8235                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8236                                  EXTENT_DEFRAG, 1, 1,
8237                                  &cached_state, GFP_NOFS);
8238
8239                 __btrfs_releasepage(page, GFP_NOFS);
8240         }
8241
8242         ClearPageChecked(page);
8243         if (PagePrivate(page)) {
8244                 ClearPagePrivate(page);
8245                 set_page_private(page, 0);
8246                 page_cache_release(page);
8247         }
8248 }
8249
8250 /*
8251  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8252  * called from a page fault handler when a page is first dirtied. Hence we must
8253  * be careful to check for EOF conditions here. We set the page up correctly
8254  * for a written page which means we get ENOSPC checking when writing into
8255  * holes and correct delalloc and unwritten extent mapping on filesystems that
8256  * support these features.
8257  *
8258  * We are not allowed to take the i_mutex here so we have to play games to
8259  * protect against truncate races as the page could now be beyond EOF.  Because
8260  * vmtruncate() writes the inode size before removing pages, once we have the
8261  * page lock we can determine safely if the page is beyond EOF. If it is not
8262  * beyond EOF, then the page is guaranteed safe against truncation until we
8263  * unlock the page.
8264  */
8265 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
8266 {
8267         struct page *page = vmf->page;
8268         struct inode *inode = file_inode(vma->vm_file);
8269         struct btrfs_root *root = BTRFS_I(inode)->root;
8270         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8271         struct btrfs_ordered_extent *ordered;
8272         struct extent_state *cached_state = NULL;
8273         char *kaddr;
8274         unsigned long zero_start;
8275         loff_t size;
8276         int ret;
8277         int reserved = 0;
8278         u64 page_start;
8279         u64 page_end;
8280
8281         sb_start_pagefault(inode->i_sb);
8282         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
8283         if (!ret) {
8284                 ret = file_update_time(vma->vm_file);
8285                 reserved = 1;
8286         }
8287         if (ret) {
8288                 if (ret == -ENOMEM)
8289                         ret = VM_FAULT_OOM;
8290                 else /* -ENOSPC, -EIO, etc */
8291                         ret = VM_FAULT_SIGBUS;
8292                 if (reserved)
8293                         goto out;
8294                 goto out_noreserve;
8295         }
8296
8297         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8298 again:
8299         lock_page(page);
8300         size = i_size_read(inode);
8301         page_start = page_offset(page);
8302         page_end = page_start + PAGE_CACHE_SIZE - 1;
8303
8304         if ((page->mapping != inode->i_mapping) ||
8305             (page_start >= size)) {
8306                 /* page got truncated out from underneath us */
8307                 goto out_unlock;
8308         }
8309         wait_on_page_writeback(page);
8310
8311         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
8312         set_page_extent_mapped(page);
8313
8314         /*
8315          * we can't set the delalloc bits if there are pending ordered
8316          * extents.  Drop our locks and wait for them to finish
8317          */
8318         ordered = btrfs_lookup_ordered_extent(inode, page_start);
8319         if (ordered) {
8320                 unlock_extent_cached(io_tree, page_start, page_end,
8321                                      &cached_state, GFP_NOFS);
8322                 unlock_page(page);
8323                 btrfs_start_ordered_extent(inode, ordered, 1);
8324                 btrfs_put_ordered_extent(ordered);
8325                 goto again;
8326         }
8327
8328         /*
8329          * XXX - page_mkwrite gets called every time the page is dirtied, even
8330          * if it was already dirty, so for space accounting reasons we need to
8331          * clear any delalloc bits for the range we are fixing to save.  There
8332          * is probably a better way to do this, but for now keep consistent with
8333          * prepare_pages in the normal write path.
8334          */
8335         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
8336                           EXTENT_DIRTY | EXTENT_DELALLOC |
8337                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8338                           0, 0, &cached_state, GFP_NOFS);
8339
8340         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
8341                                         &cached_state);
8342         if (ret) {
8343                 unlock_extent_cached(io_tree, page_start, page_end,
8344                                      &cached_state, GFP_NOFS);
8345                 ret = VM_FAULT_SIGBUS;
8346                 goto out_unlock;
8347         }
8348         ret = 0;
8349
8350         /* page is wholly or partially inside EOF */
8351         if (page_start + PAGE_CACHE_SIZE > size)
8352                 zero_start = size & ~PAGE_CACHE_MASK;
8353         else
8354                 zero_start = PAGE_CACHE_SIZE;
8355
8356         if (zero_start != PAGE_CACHE_SIZE) {
8357                 kaddr = kmap(page);
8358                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
8359                 flush_dcache_page(page);
8360                 kunmap(page);
8361         }
8362         ClearPageChecked(page);
8363         set_page_dirty(page);
8364         SetPageUptodate(page);
8365
8366         BTRFS_I(inode)->last_trans = root->fs_info->generation;
8367         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8368         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8369
8370         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
8371
8372 out_unlock:
8373         if (!ret) {
8374                 sb_end_pagefault(inode->i_sb);
8375                 return VM_FAULT_LOCKED;
8376         }
8377         unlock_page(page);
8378 out:
8379         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
8380 out_noreserve:
8381         sb_end_pagefault(inode->i_sb);
8382         return ret;
8383 }
8384
8385 static int btrfs_truncate(struct inode *inode)
8386 {
8387         struct btrfs_root *root = BTRFS_I(inode)->root;
8388         struct btrfs_block_rsv *rsv;
8389         int ret = 0;
8390         int err = 0;
8391         struct btrfs_trans_handle *trans;
8392         u64 mask = root->sectorsize - 1;
8393         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
8394
8395         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
8396                                        (u64)-1);
8397         if (ret)
8398                 return ret;
8399
8400         /*
8401          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
8402          * 3 things going on here
8403          *
8404          * 1) We need to reserve space for our orphan item and the space to
8405          * delete our orphan item.  Lord knows we don't want to have a dangling
8406          * orphan item because we didn't reserve space to remove it.
8407          *
8408          * 2) We need to reserve space to update our inode.
8409          *
8410          * 3) We need to have something to cache all the space that is going to
8411          * be free'd up by the truncate operation, but also have some slack
8412          * space reserved in case it uses space during the truncate (thank you
8413          * very much snapshotting).
8414          *
8415          * And we need these to all be seperate.  The fact is we can use alot of
8416          * space doing the truncate, and we have no earthly idea how much space
8417          * we will use, so we need the truncate reservation to be seperate so it
8418          * doesn't end up using space reserved for updating the inode or
8419          * removing the orphan item.  We also need to be able to stop the
8420          * transaction and start a new one, which means we need to be able to
8421          * update the inode several times, and we have no idea of knowing how
8422          * many times that will be, so we can't just reserve 1 item for the
8423          * entirety of the opration, so that has to be done seperately as well.
8424          * Then there is the orphan item, which does indeed need to be held on
8425          * to for the whole operation, and we need nobody to touch this reserved
8426          * space except the orphan code.
8427          *
8428          * So that leaves us with
8429          *
8430          * 1) root->orphan_block_rsv - for the orphan deletion.
8431          * 2) rsv - for the truncate reservation, which we will steal from the
8432          * transaction reservation.
8433          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
8434          * updating the inode.
8435          */
8436         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
8437         if (!rsv)
8438                 return -ENOMEM;
8439         rsv->size = min_size;
8440         rsv->failfast = 1;
8441
8442         /*
8443          * 1 for the truncate slack space
8444          * 1 for updating the inode.
8445          */
8446         trans = btrfs_start_transaction(root, 2);
8447         if (IS_ERR(trans)) {
8448                 err = PTR_ERR(trans);
8449                 goto out;
8450         }
8451
8452         /* Migrate the slack space for the truncate to our reserve */
8453         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
8454                                       min_size);
8455         BUG_ON(ret);
8456
8457         /*
8458          * So if we truncate and then write and fsync we normally would just
8459          * write the extents that changed, which is a problem if we need to
8460          * first truncate that entire inode.  So set this flag so we write out
8461          * all of the extents in the inode to the sync log so we're completely
8462          * safe.
8463          */
8464         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
8465         trans->block_rsv = rsv;
8466
8467         while (1) {
8468                 ret = btrfs_truncate_inode_items(trans, root, inode,
8469                                                  inode->i_size,
8470                                                  BTRFS_EXTENT_DATA_KEY);
8471                 if (ret != -ENOSPC) {
8472                         err = ret;
8473                         break;
8474                 }
8475
8476                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8477                 ret = btrfs_update_inode(trans, root, inode);
8478                 if (ret) {
8479                         err = ret;
8480                         break;
8481                 }
8482
8483                 btrfs_end_transaction(trans, root);
8484                 btrfs_btree_balance_dirty(root);
8485
8486                 trans = btrfs_start_transaction(root, 2);
8487                 if (IS_ERR(trans)) {
8488                         ret = err = PTR_ERR(trans);
8489                         trans = NULL;
8490                         break;
8491                 }
8492
8493                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
8494                                               rsv, min_size);
8495                 BUG_ON(ret);    /* shouldn't happen */
8496                 trans->block_rsv = rsv;
8497         }
8498
8499         if (ret == 0 && inode->i_nlink > 0) {
8500                 trans->block_rsv = root->orphan_block_rsv;
8501                 ret = btrfs_orphan_del(trans, inode);
8502                 if (ret)
8503                         err = ret;
8504         }
8505
8506         if (trans) {
8507                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8508                 ret = btrfs_update_inode(trans, root, inode);
8509                 if (ret && !err)
8510                         err = ret;
8511
8512                 ret = btrfs_end_transaction(trans, root);
8513                 btrfs_btree_balance_dirty(root);
8514         }
8515
8516 out:
8517         btrfs_free_block_rsv(root, rsv);
8518
8519         if (ret && !err)
8520                 err = ret;
8521
8522         return err;
8523 }
8524
8525 /*
8526  * create a new subvolume directory/inode (helper for the ioctl).
8527  */
8528 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
8529                              struct btrfs_root *new_root,
8530                              struct btrfs_root *parent_root,
8531                              u64 new_dirid)
8532 {
8533         struct inode *inode;
8534         int err;
8535         u64 index = 0;
8536
8537         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
8538                                 new_dirid, new_dirid,
8539                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
8540                                 &index);
8541         if (IS_ERR(inode))
8542                 return PTR_ERR(inode);
8543         inode->i_op = &btrfs_dir_inode_operations;
8544         inode->i_fop = &btrfs_dir_file_operations;
8545
8546         set_nlink(inode, 1);
8547         btrfs_i_size_write(inode, 0);
8548         unlock_new_inode(inode);
8549
8550         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
8551         if (err)
8552                 btrfs_err(new_root->fs_info,
8553                           "error inheriting subvolume %llu properties: %d",
8554                           new_root->root_key.objectid, err);
8555
8556         err = btrfs_update_inode(trans, new_root, inode);
8557
8558         iput(inode);
8559         return err;
8560 }
8561
8562 struct inode *btrfs_alloc_inode(struct super_block *sb)
8563 {
8564         struct btrfs_inode *ei;
8565         struct inode *inode;
8566
8567         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
8568         if (!ei)
8569                 return NULL;
8570
8571         ei->root = NULL;
8572         ei->generation = 0;
8573         ei->last_trans = 0;
8574         ei->last_sub_trans = 0;
8575         ei->logged_trans = 0;
8576         ei->delalloc_bytes = 0;
8577         ei->defrag_bytes = 0;
8578         ei->disk_i_size = 0;
8579         ei->flags = 0;
8580         ei->csum_bytes = 0;
8581         ei->index_cnt = (u64)-1;
8582         ei->dir_index = 0;
8583         ei->last_unlink_trans = 0;
8584         ei->last_log_commit = 0;
8585
8586         spin_lock_init(&ei->lock);
8587         ei->outstanding_extents = 0;
8588         ei->reserved_extents = 0;
8589
8590         ei->runtime_flags = 0;
8591         ei->force_compress = BTRFS_COMPRESS_NONE;
8592
8593         ei->delayed_node = NULL;
8594
8595         ei->i_otime.tv_sec = 0;
8596         ei->i_otime.tv_nsec = 0;
8597
8598         inode = &ei->vfs_inode;
8599         extent_map_tree_init(&ei->extent_tree);
8600         extent_io_tree_init(&ei->io_tree, &inode->i_data);
8601         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
8602         ei->io_tree.track_uptodate = 1;
8603         ei->io_failure_tree.track_uptodate = 1;
8604         atomic_set(&ei->sync_writers, 0);
8605         mutex_init(&ei->log_mutex);
8606         mutex_init(&ei->delalloc_mutex);
8607         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
8608         INIT_LIST_HEAD(&ei->delalloc_inodes);
8609         RB_CLEAR_NODE(&ei->rb_node);
8610
8611         return inode;
8612 }
8613
8614 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8615 void btrfs_test_destroy_inode(struct inode *inode)
8616 {
8617         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8618         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8619 }
8620 #endif
8621
8622 static void btrfs_i_callback(struct rcu_head *head)
8623 {
8624         struct inode *inode = container_of(head, struct inode, i_rcu);
8625         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8626 }
8627
8628 void btrfs_destroy_inode(struct inode *inode)
8629 {
8630         struct btrfs_ordered_extent *ordered;
8631         struct btrfs_root *root = BTRFS_I(inode)->root;
8632
8633         WARN_ON(!hlist_empty(&inode->i_dentry));
8634         WARN_ON(inode->i_data.nrpages);
8635         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8636         WARN_ON(BTRFS_I(inode)->reserved_extents);
8637         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8638         WARN_ON(BTRFS_I(inode)->csum_bytes);
8639         WARN_ON(BTRFS_I(inode)->defrag_bytes);
8640
8641         /*
8642          * This can happen where we create an inode, but somebody else also
8643          * created the same inode and we need to destroy the one we already
8644          * created.
8645          */
8646         if (!root)
8647                 goto free;
8648
8649         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
8650                      &BTRFS_I(inode)->runtime_flags)) {
8651                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
8652                         btrfs_ino(inode));
8653                 atomic_dec(&root->orphan_inodes);
8654         }
8655
8656         while (1) {
8657                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8658                 if (!ordered)
8659                         break;
8660                 else {
8661                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
8662                                 ordered->file_offset, ordered->len);
8663                         btrfs_remove_ordered_extent(inode, ordered);
8664                         btrfs_put_ordered_extent(ordered);
8665                         btrfs_put_ordered_extent(ordered);
8666                 }
8667         }
8668         inode_tree_del(inode);
8669         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8670 free:
8671         call_rcu(&inode->i_rcu, btrfs_i_callback);
8672 }
8673
8674 int btrfs_drop_inode(struct inode *inode)
8675 {
8676         struct btrfs_root *root = BTRFS_I(inode)->root;
8677
8678         if (root == NULL)
8679                 return 1;
8680
8681         /* the snap/subvol tree is on deleting */
8682         if (btrfs_root_refs(&root->root_item) == 0)
8683                 return 1;
8684         else
8685                 return generic_drop_inode(inode);
8686 }
8687
8688 static void init_once(void *foo)
8689 {
8690         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8691
8692         inode_init_once(&ei->vfs_inode);
8693 }
8694
8695 void btrfs_destroy_cachep(void)
8696 {
8697         /*
8698          * Make sure all delayed rcu free inodes are flushed before we
8699          * destroy cache.
8700          */
8701         rcu_barrier();
8702         if (btrfs_inode_cachep)
8703                 kmem_cache_destroy(btrfs_inode_cachep);
8704         if (btrfs_trans_handle_cachep)
8705                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8706         if (btrfs_transaction_cachep)
8707                 kmem_cache_destroy(btrfs_transaction_cachep);
8708         if (btrfs_path_cachep)
8709                 kmem_cache_destroy(btrfs_path_cachep);
8710         if (btrfs_free_space_cachep)
8711                 kmem_cache_destroy(btrfs_free_space_cachep);
8712         if (btrfs_delalloc_work_cachep)
8713                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8714 }
8715
8716 int btrfs_init_cachep(void)
8717 {
8718         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8719                         sizeof(struct btrfs_inode), 0,
8720                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8721         if (!btrfs_inode_cachep)
8722                 goto fail;
8723
8724         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8725                         sizeof(struct btrfs_trans_handle), 0,
8726                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8727         if (!btrfs_trans_handle_cachep)
8728                 goto fail;
8729
8730         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8731                         sizeof(struct btrfs_transaction), 0,
8732                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8733         if (!btrfs_transaction_cachep)
8734                 goto fail;
8735
8736         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8737                         sizeof(struct btrfs_path), 0,
8738                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8739         if (!btrfs_path_cachep)
8740                 goto fail;
8741
8742         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8743                         sizeof(struct btrfs_free_space), 0,
8744                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8745         if (!btrfs_free_space_cachep)
8746                 goto fail;
8747
8748         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8749                         sizeof(struct btrfs_delalloc_work), 0,
8750                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8751                         NULL);
8752         if (!btrfs_delalloc_work_cachep)
8753                 goto fail;
8754
8755         return 0;
8756 fail:
8757         btrfs_destroy_cachep();
8758         return -ENOMEM;
8759 }
8760
8761 static int btrfs_getattr(struct vfsmount *mnt,
8762                          struct dentry *dentry, struct kstat *stat)
8763 {
8764         u64 delalloc_bytes;
8765         struct inode *inode = dentry->d_inode;
8766         u32 blocksize = inode->i_sb->s_blocksize;
8767
8768         generic_fillattr(inode, stat);
8769         stat->dev = BTRFS_I(inode)->root->anon_dev;
8770         stat->blksize = PAGE_CACHE_SIZE;
8771
8772         spin_lock(&BTRFS_I(inode)->lock);
8773         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8774         spin_unlock(&BTRFS_I(inode)->lock);
8775         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8776                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8777         return 0;
8778 }
8779
8780 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8781                            struct inode *new_dir, struct dentry *new_dentry)
8782 {
8783         struct btrfs_trans_handle *trans;
8784         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8785         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8786         struct inode *new_inode = new_dentry->d_inode;
8787         struct inode *old_inode = old_dentry->d_inode;
8788         struct timespec ctime = CURRENT_TIME;
8789         u64 index = 0;
8790         u64 root_objectid;
8791         int ret;
8792         u64 old_ino = btrfs_ino(old_inode);
8793
8794         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8795                 return -EPERM;
8796
8797         /* we only allow rename subvolume link between subvolumes */
8798         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8799                 return -EXDEV;
8800
8801         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8802             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8803                 return -ENOTEMPTY;
8804
8805         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8806             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8807                 return -ENOTEMPTY;
8808
8809
8810         /* check for collisions, even if the  name isn't there */
8811         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8812                              new_dentry->d_name.name,
8813                              new_dentry->d_name.len);
8814
8815         if (ret) {
8816                 if (ret == -EEXIST) {
8817                         /* we shouldn't get
8818                          * eexist without a new_inode */
8819                         if (WARN_ON(!new_inode)) {
8820                                 return ret;
8821                         }
8822                 } else {
8823                         /* maybe -EOVERFLOW */
8824                         return ret;
8825                 }
8826         }
8827         ret = 0;
8828
8829         /*
8830          * we're using rename to replace one file with another.  Start IO on it
8831          * now so  we don't add too much work to the end of the transaction
8832          */
8833         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
8834                 filemap_flush(old_inode->i_mapping);
8835
8836         /* close the racy window with snapshot create/destroy ioctl */
8837         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8838                 down_read(&root->fs_info->subvol_sem);
8839         /*
8840          * We want to reserve the absolute worst case amount of items.  So if
8841          * both inodes are subvols and we need to unlink them then that would
8842          * require 4 item modifications, but if they are both normal inodes it
8843          * would require 5 item modifications, so we'll assume their normal
8844          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8845          * should cover the worst case number of items we'll modify.
8846          */
8847         trans = btrfs_start_transaction(root, 11);
8848         if (IS_ERR(trans)) {
8849                 ret = PTR_ERR(trans);
8850                 goto out_notrans;
8851         }
8852
8853         if (dest != root)
8854                 btrfs_record_root_in_trans(trans, dest);
8855
8856         ret = btrfs_set_inode_index(new_dir, &index);
8857         if (ret)
8858                 goto out_fail;
8859
8860         BTRFS_I(old_inode)->dir_index = 0ULL;
8861         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8862                 /* force full log commit if subvolume involved. */
8863                 btrfs_set_log_full_commit(root->fs_info, trans);
8864         } else {
8865                 ret = btrfs_insert_inode_ref(trans, dest,
8866                                              new_dentry->d_name.name,
8867                                              new_dentry->d_name.len,
8868                                              old_ino,
8869                                              btrfs_ino(new_dir), index);
8870                 if (ret)
8871                         goto out_fail;
8872                 /*
8873                  * this is an ugly little race, but the rename is required
8874                  * to make sure that if we crash, the inode is either at the
8875                  * old name or the new one.  pinning the log transaction lets
8876                  * us make sure we don't allow a log commit to come in after
8877                  * we unlink the name but before we add the new name back in.
8878                  */
8879                 btrfs_pin_log_trans(root);
8880         }
8881
8882         inode_inc_iversion(old_dir);
8883         inode_inc_iversion(new_dir);
8884         inode_inc_iversion(old_inode);
8885         old_dir->i_ctime = old_dir->i_mtime = ctime;
8886         new_dir->i_ctime = new_dir->i_mtime = ctime;
8887         old_inode->i_ctime = ctime;
8888
8889         if (old_dentry->d_parent != new_dentry->d_parent)
8890                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8891
8892         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8893                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8894                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8895                                         old_dentry->d_name.name,
8896                                         old_dentry->d_name.len);
8897         } else {
8898                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8899                                         old_dentry->d_inode,
8900                                         old_dentry->d_name.name,
8901                                         old_dentry->d_name.len);
8902                 if (!ret)
8903                         ret = btrfs_update_inode(trans, root, old_inode);
8904         }
8905         if (ret) {
8906                 btrfs_abort_transaction(trans, root, ret);
8907                 goto out_fail;
8908         }
8909
8910         if (new_inode) {
8911                 inode_inc_iversion(new_inode);
8912                 new_inode->i_ctime = CURRENT_TIME;
8913                 if (unlikely(btrfs_ino(new_inode) ==
8914                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8915                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8916                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8917                                                 root_objectid,
8918                                                 new_dentry->d_name.name,
8919                                                 new_dentry->d_name.len);
8920                         BUG_ON(new_inode->i_nlink == 0);
8921                 } else {
8922                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8923                                                  new_dentry->d_inode,
8924                                                  new_dentry->d_name.name,
8925                                                  new_dentry->d_name.len);
8926                 }
8927                 if (!ret && new_inode->i_nlink == 0)
8928                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8929                 if (ret) {
8930                         btrfs_abort_transaction(trans, root, ret);
8931                         goto out_fail;
8932                 }
8933         }
8934
8935         ret = btrfs_add_link(trans, new_dir, old_inode,
8936                              new_dentry->d_name.name,
8937                              new_dentry->d_name.len, 0, index);
8938         if (ret) {
8939                 btrfs_abort_transaction(trans, root, ret);
8940                 goto out_fail;
8941         }
8942
8943         if (old_inode->i_nlink == 1)
8944                 BTRFS_I(old_inode)->dir_index = index;
8945
8946         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8947                 struct dentry *parent = new_dentry->d_parent;
8948                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8949                 btrfs_end_log_trans(root);
8950         }
8951 out_fail:
8952         btrfs_end_transaction(trans, root);
8953 out_notrans:
8954         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8955                 up_read(&root->fs_info->subvol_sem);
8956
8957         return ret;
8958 }
8959
8960 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
8961                          struct inode *new_dir, struct dentry *new_dentry,
8962                          unsigned int flags)
8963 {
8964         if (flags & ~RENAME_NOREPLACE)
8965                 return -EINVAL;
8966
8967         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry);
8968 }
8969
8970 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8971 {
8972         struct btrfs_delalloc_work *delalloc_work;
8973         struct inode *inode;
8974
8975         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8976                                      work);
8977         inode = delalloc_work->inode;
8978         if (delalloc_work->wait) {
8979                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8980         } else {
8981                 filemap_flush(inode->i_mapping);
8982                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8983                              &BTRFS_I(inode)->runtime_flags))
8984                         filemap_flush(inode->i_mapping);
8985         }
8986
8987         if (delalloc_work->delay_iput)
8988                 btrfs_add_delayed_iput(inode);
8989         else
8990                 iput(inode);
8991         complete(&delalloc_work->completion);
8992 }
8993
8994 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8995                                                     int wait, int delay_iput)
8996 {
8997         struct btrfs_delalloc_work *work;
8998
8999         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
9000         if (!work)
9001                 return NULL;
9002
9003         init_completion(&work->completion);
9004         INIT_LIST_HEAD(&work->list);
9005         work->inode = inode;
9006         work->wait = wait;
9007         work->delay_iput = delay_iput;
9008         WARN_ON_ONCE(!inode);
9009         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9010                         btrfs_run_delalloc_work, NULL, NULL);
9011
9012         return work;
9013 }
9014
9015 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
9016 {
9017         wait_for_completion(&work->completion);
9018         kmem_cache_free(btrfs_delalloc_work_cachep, work);
9019 }
9020
9021 /*
9022  * some fairly slow code that needs optimization. This walks the list
9023  * of all the inodes with pending delalloc and forces them to disk.
9024  */
9025 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
9026                                    int nr)
9027 {
9028         struct btrfs_inode *binode;
9029         struct inode *inode;
9030         struct btrfs_delalloc_work *work, *next;
9031         struct list_head works;
9032         struct list_head splice;
9033         int ret = 0;
9034
9035         INIT_LIST_HEAD(&works);
9036         INIT_LIST_HEAD(&splice);
9037
9038         mutex_lock(&root->delalloc_mutex);
9039         spin_lock(&root->delalloc_lock);
9040         list_splice_init(&root->delalloc_inodes, &splice);
9041         while (!list_empty(&splice)) {
9042                 binode = list_entry(splice.next, struct btrfs_inode,
9043                                     delalloc_inodes);
9044
9045                 list_move_tail(&binode->delalloc_inodes,
9046                                &root->delalloc_inodes);
9047                 inode = igrab(&binode->vfs_inode);
9048                 if (!inode) {
9049                         cond_resched_lock(&root->delalloc_lock);
9050                         continue;
9051                 }
9052                 spin_unlock(&root->delalloc_lock);
9053
9054                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
9055                 if (!work) {
9056                         if (delay_iput)
9057                                 btrfs_add_delayed_iput(inode);
9058                         else
9059                                 iput(inode);
9060                         ret = -ENOMEM;
9061                         goto out;
9062                 }
9063                 list_add_tail(&work->list, &works);
9064                 btrfs_queue_work(root->fs_info->flush_workers,
9065                                  &work->work);
9066                 ret++;
9067                 if (nr != -1 && ret >= nr)
9068                         goto out;
9069                 cond_resched();
9070                 spin_lock(&root->delalloc_lock);
9071         }
9072         spin_unlock(&root->delalloc_lock);
9073
9074 out:
9075         list_for_each_entry_safe(work, next, &works, list) {
9076                 list_del_init(&work->list);
9077                 btrfs_wait_and_free_delalloc_work(work);
9078         }
9079
9080         if (!list_empty_careful(&splice)) {
9081                 spin_lock(&root->delalloc_lock);
9082                 list_splice_tail(&splice, &root->delalloc_inodes);
9083                 spin_unlock(&root->delalloc_lock);
9084         }
9085         mutex_unlock(&root->delalloc_mutex);
9086         return ret;
9087 }
9088
9089 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
9090 {
9091         int ret;
9092
9093         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
9094                 return -EROFS;
9095
9096         ret = __start_delalloc_inodes(root, delay_iput, -1);
9097         if (ret > 0)
9098                 ret = 0;
9099         /*
9100          * the filemap_flush will queue IO into the worker threads, but
9101          * we have to make sure the IO is actually started and that
9102          * ordered extents get created before we return
9103          */
9104         atomic_inc(&root->fs_info->async_submit_draining);
9105         while (atomic_read(&root->fs_info->nr_async_submits) ||
9106               atomic_read(&root->fs_info->async_delalloc_pages)) {
9107                 wait_event(root->fs_info->async_submit_wait,
9108                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
9109                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
9110         }
9111         atomic_dec(&root->fs_info->async_submit_draining);
9112         return ret;
9113 }
9114
9115 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
9116                                int nr)
9117 {
9118         struct btrfs_root *root;
9119         struct list_head splice;
9120         int ret;
9121
9122         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
9123                 return -EROFS;
9124
9125         INIT_LIST_HEAD(&splice);
9126
9127         mutex_lock(&fs_info->delalloc_root_mutex);
9128         spin_lock(&fs_info->delalloc_root_lock);
9129         list_splice_init(&fs_info->delalloc_roots, &splice);
9130         while (!list_empty(&splice) && nr) {
9131                 root = list_first_entry(&splice, struct btrfs_root,
9132                                         delalloc_root);
9133                 root = btrfs_grab_fs_root(root);
9134                 BUG_ON(!root);
9135                 list_move_tail(&root->delalloc_root,
9136                                &fs_info->delalloc_roots);
9137                 spin_unlock(&fs_info->delalloc_root_lock);
9138
9139                 ret = __start_delalloc_inodes(root, delay_iput, nr);
9140                 btrfs_put_fs_root(root);
9141                 if (ret < 0)
9142                         goto out;
9143
9144                 if (nr != -1) {
9145                         nr -= ret;
9146                         WARN_ON(nr < 0);
9147                 }
9148                 spin_lock(&fs_info->delalloc_root_lock);
9149         }
9150         spin_unlock(&fs_info->delalloc_root_lock);
9151
9152         ret = 0;
9153         atomic_inc(&fs_info->async_submit_draining);
9154         while (atomic_read(&fs_info->nr_async_submits) ||
9155               atomic_read(&fs_info->async_delalloc_pages)) {
9156                 wait_event(fs_info->async_submit_wait,
9157                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
9158                     atomic_read(&fs_info->async_delalloc_pages) == 0));
9159         }
9160         atomic_dec(&fs_info->async_submit_draining);
9161 out:
9162         if (!list_empty_careful(&splice)) {
9163                 spin_lock(&fs_info->delalloc_root_lock);
9164                 list_splice_tail(&splice, &fs_info->delalloc_roots);
9165                 spin_unlock(&fs_info->delalloc_root_lock);
9166         }
9167         mutex_unlock(&fs_info->delalloc_root_mutex);
9168         return ret;
9169 }
9170
9171 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
9172                          const char *symname)
9173 {
9174         struct btrfs_trans_handle *trans;
9175         struct btrfs_root *root = BTRFS_I(dir)->root;
9176         struct btrfs_path *path;
9177         struct btrfs_key key;
9178         struct inode *inode = NULL;
9179         int err;
9180         int drop_inode = 0;
9181         u64 objectid;
9182         u64 index = 0;
9183         int name_len;
9184         int datasize;
9185         unsigned long ptr;
9186         struct btrfs_file_extent_item *ei;
9187         struct extent_buffer *leaf;
9188
9189         name_len = strlen(symname);
9190         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
9191                 return -ENAMETOOLONG;
9192
9193         /*
9194          * 2 items for inode item and ref
9195          * 2 items for dir items
9196          * 1 item for xattr if selinux is on
9197          */
9198         trans = btrfs_start_transaction(root, 5);
9199         if (IS_ERR(trans))
9200                 return PTR_ERR(trans);
9201
9202         err = btrfs_find_free_ino(root, &objectid);
9203         if (err)
9204                 goto out_unlock;
9205
9206         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
9207                                 dentry->d_name.len, btrfs_ino(dir), objectid,
9208                                 S_IFLNK|S_IRWXUGO, &index);
9209         if (IS_ERR(inode)) {
9210                 err = PTR_ERR(inode);
9211                 goto out_unlock;
9212         }
9213
9214         /*
9215         * If the active LSM wants to access the inode during
9216         * d_instantiate it needs these. Smack checks to see
9217         * if the filesystem supports xattrs by looking at the
9218         * ops vector.
9219         */
9220         inode->i_fop = &btrfs_file_operations;
9221         inode->i_op = &btrfs_file_inode_operations;
9222         inode->i_mapping->a_ops = &btrfs_aops;
9223         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9224         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9225
9226         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
9227         if (err)
9228                 goto out_unlock_inode;
9229
9230         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
9231         if (err)
9232                 goto out_unlock_inode;
9233
9234         path = btrfs_alloc_path();
9235         if (!path) {
9236                 err = -ENOMEM;
9237                 goto out_unlock_inode;
9238         }
9239         key.objectid = btrfs_ino(inode);
9240         key.offset = 0;
9241         key.type = BTRFS_EXTENT_DATA_KEY;
9242         datasize = btrfs_file_extent_calc_inline_size(name_len);
9243         err = btrfs_insert_empty_item(trans, root, path, &key,
9244                                       datasize);
9245         if (err) {
9246                 btrfs_free_path(path);
9247                 goto out_unlock_inode;
9248         }
9249         leaf = path->nodes[0];
9250         ei = btrfs_item_ptr(leaf, path->slots[0],
9251                             struct btrfs_file_extent_item);
9252         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
9253         btrfs_set_file_extent_type(leaf, ei,
9254                                    BTRFS_FILE_EXTENT_INLINE);
9255         btrfs_set_file_extent_encryption(leaf, ei, 0);
9256         btrfs_set_file_extent_compression(leaf, ei, 0);
9257         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
9258         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
9259
9260         ptr = btrfs_file_extent_inline_start(ei);
9261         write_extent_buffer(leaf, symname, ptr, name_len);
9262         btrfs_mark_buffer_dirty(leaf);
9263         btrfs_free_path(path);
9264
9265         inode->i_op = &btrfs_symlink_inode_operations;
9266         inode->i_mapping->a_ops = &btrfs_symlink_aops;
9267         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9268         inode_set_bytes(inode, name_len);
9269         btrfs_i_size_write(inode, name_len);
9270         err = btrfs_update_inode(trans, root, inode);
9271         if (err) {
9272                 drop_inode = 1;
9273                 goto out_unlock_inode;
9274         }
9275
9276         unlock_new_inode(inode);
9277         d_instantiate(dentry, inode);
9278
9279 out_unlock:
9280         btrfs_end_transaction(trans, root);
9281         if (drop_inode) {
9282                 inode_dec_link_count(inode);
9283                 iput(inode);
9284         }
9285         btrfs_btree_balance_dirty(root);
9286         return err;
9287
9288 out_unlock_inode:
9289         drop_inode = 1;
9290         unlock_new_inode(inode);
9291         goto out_unlock;
9292 }
9293
9294 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
9295                                        u64 start, u64 num_bytes, u64 min_size,
9296                                        loff_t actual_len, u64 *alloc_hint,
9297                                        struct btrfs_trans_handle *trans)
9298 {
9299         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
9300         struct extent_map *em;
9301         struct btrfs_root *root = BTRFS_I(inode)->root;
9302         struct btrfs_key ins;
9303         u64 cur_offset = start;
9304         u64 i_size;
9305         u64 cur_bytes;
9306         int ret = 0;
9307         bool own_trans = true;
9308
9309         if (trans)
9310                 own_trans = false;
9311         while (num_bytes > 0) {
9312                 if (own_trans) {
9313                         trans = btrfs_start_transaction(root, 3);
9314                         if (IS_ERR(trans)) {
9315                                 ret = PTR_ERR(trans);
9316                                 break;
9317                         }
9318                 }
9319
9320                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
9321                 cur_bytes = max(cur_bytes, min_size);
9322                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
9323                                            *alloc_hint, &ins, 1, 0);
9324                 if (ret) {
9325                         if (own_trans)
9326                                 btrfs_end_transaction(trans, root);
9327                         break;
9328                 }
9329
9330                 ret = insert_reserved_file_extent(trans, inode,
9331                                                   cur_offset, ins.objectid,
9332                                                   ins.offset, ins.offset,
9333                                                   ins.offset, 0, 0, 0,
9334                                                   BTRFS_FILE_EXTENT_PREALLOC);
9335                 if (ret) {
9336                         btrfs_free_reserved_extent(root, ins.objectid,
9337                                                    ins.offset, 0);
9338                         btrfs_abort_transaction(trans, root, ret);
9339                         if (own_trans)
9340                                 btrfs_end_transaction(trans, root);
9341                         break;
9342                 }
9343                 btrfs_drop_extent_cache(inode, cur_offset,
9344                                         cur_offset + ins.offset -1, 0);
9345
9346                 em = alloc_extent_map();
9347                 if (!em) {
9348                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
9349                                 &BTRFS_I(inode)->runtime_flags);
9350                         goto next;
9351                 }
9352
9353                 em->start = cur_offset;
9354                 em->orig_start = cur_offset;
9355                 em->len = ins.offset;
9356                 em->block_start = ins.objectid;
9357                 em->block_len = ins.offset;
9358                 em->orig_block_len = ins.offset;
9359                 em->ram_bytes = ins.offset;
9360                 em->bdev = root->fs_info->fs_devices->latest_bdev;
9361                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
9362                 em->generation = trans->transid;
9363
9364                 while (1) {
9365                         write_lock(&em_tree->lock);
9366                         ret = add_extent_mapping(em_tree, em, 1);
9367                         write_unlock(&em_tree->lock);
9368                         if (ret != -EEXIST)
9369                                 break;
9370                         btrfs_drop_extent_cache(inode, cur_offset,
9371                                                 cur_offset + ins.offset - 1,
9372                                                 0);
9373                 }
9374                 free_extent_map(em);
9375 next:
9376                 num_bytes -= ins.offset;
9377                 cur_offset += ins.offset;
9378                 *alloc_hint = ins.objectid + ins.offset;
9379
9380                 inode_inc_iversion(inode);
9381                 inode->i_ctime = CURRENT_TIME;
9382                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
9383                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
9384                     (actual_len > inode->i_size) &&
9385                     (cur_offset > inode->i_size)) {
9386                         if (cur_offset > actual_len)
9387                                 i_size = actual_len;
9388                         else
9389                                 i_size = cur_offset;
9390                         i_size_write(inode, i_size);
9391                         btrfs_ordered_update_i_size(inode, i_size, NULL);
9392                 }
9393
9394                 ret = btrfs_update_inode(trans, root, inode);
9395
9396                 if (ret) {
9397                         btrfs_abort_transaction(trans, root, ret);
9398                         if (own_trans)
9399                                 btrfs_end_transaction(trans, root);
9400                         break;
9401                 }
9402
9403                 if (own_trans)
9404                         btrfs_end_transaction(trans, root);
9405         }
9406         return ret;
9407 }
9408
9409 int btrfs_prealloc_file_range(struct inode *inode, int mode,
9410                               u64 start, u64 num_bytes, u64 min_size,
9411                               loff_t actual_len, u64 *alloc_hint)
9412 {
9413         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9414                                            min_size, actual_len, alloc_hint,
9415                                            NULL);
9416 }
9417
9418 int btrfs_prealloc_file_range_trans(struct inode *inode,
9419                                     struct btrfs_trans_handle *trans, int mode,
9420                                     u64 start, u64 num_bytes, u64 min_size,
9421                                     loff_t actual_len, u64 *alloc_hint)
9422 {
9423         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9424                                            min_size, actual_len, alloc_hint, trans);
9425 }
9426
9427 static int btrfs_set_page_dirty(struct page *page)
9428 {
9429         return __set_page_dirty_nobuffers(page);
9430 }
9431
9432 static int btrfs_permission(struct inode *inode, int mask)
9433 {
9434         struct btrfs_root *root = BTRFS_I(inode)->root;
9435         umode_t mode = inode->i_mode;
9436
9437         if (mask & MAY_WRITE &&
9438             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
9439                 if (btrfs_root_readonly(root))
9440                         return -EROFS;
9441                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
9442                         return -EACCES;
9443         }
9444         return generic_permission(inode, mask);
9445 }
9446
9447 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
9448 {
9449         struct btrfs_trans_handle *trans;
9450         struct btrfs_root *root = BTRFS_I(dir)->root;
9451         struct inode *inode = NULL;
9452         u64 objectid;
9453         u64 index;
9454         int ret = 0;
9455
9456         /*
9457          * 5 units required for adding orphan entry
9458          */
9459         trans = btrfs_start_transaction(root, 5);
9460         if (IS_ERR(trans))
9461                 return PTR_ERR(trans);
9462
9463         ret = btrfs_find_free_ino(root, &objectid);
9464         if (ret)
9465                 goto out;
9466
9467         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
9468                                 btrfs_ino(dir), objectid, mode, &index);
9469         if (IS_ERR(inode)) {
9470                 ret = PTR_ERR(inode);
9471                 inode = NULL;
9472                 goto out;
9473         }
9474
9475         inode->i_fop = &btrfs_file_operations;
9476         inode->i_op = &btrfs_file_inode_operations;
9477
9478         inode->i_mapping->a_ops = &btrfs_aops;
9479         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9480         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9481
9482         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
9483         if (ret)
9484                 goto out_inode;
9485
9486         ret = btrfs_update_inode(trans, root, inode);
9487         if (ret)
9488                 goto out_inode;
9489         ret = btrfs_orphan_add(trans, inode);
9490         if (ret)
9491                 goto out_inode;
9492
9493         /*
9494          * We set number of links to 0 in btrfs_new_inode(), and here we set
9495          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
9496          * through:
9497          *
9498          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
9499          */
9500         set_nlink(inode, 1);
9501         unlock_new_inode(inode);
9502         d_tmpfile(dentry, inode);
9503         mark_inode_dirty(inode);
9504
9505 out:
9506         btrfs_end_transaction(trans, root);
9507         if (ret)
9508                 iput(inode);
9509         btrfs_balance_delayed_items(root);
9510         btrfs_btree_balance_dirty(root);
9511         return ret;
9512
9513 out_inode:
9514         unlock_new_inode(inode);
9515         goto out;
9516
9517 }
9518
9519 /* Inspired by filemap_check_errors() */
9520 int btrfs_inode_check_errors(struct inode *inode)
9521 {
9522         int ret = 0;
9523
9524         if (test_bit(AS_ENOSPC, &inode->i_mapping->flags) &&
9525             test_and_clear_bit(AS_ENOSPC, &inode->i_mapping->flags))
9526                 ret = -ENOSPC;
9527         if (test_bit(AS_EIO, &inode->i_mapping->flags) &&
9528             test_and_clear_bit(AS_EIO, &inode->i_mapping->flags))
9529                 ret = -EIO;
9530
9531         return ret;
9532 }
9533
9534 static const struct inode_operations btrfs_dir_inode_operations = {
9535         .getattr        = btrfs_getattr,
9536         .lookup         = btrfs_lookup,
9537         .create         = btrfs_create,
9538         .unlink         = btrfs_unlink,
9539         .link           = btrfs_link,
9540         .mkdir          = btrfs_mkdir,
9541         .rmdir          = btrfs_rmdir,
9542         .rename2        = btrfs_rename2,
9543         .symlink        = btrfs_symlink,
9544         .setattr        = btrfs_setattr,
9545         .mknod          = btrfs_mknod,
9546         .setxattr       = btrfs_setxattr,
9547         .getxattr       = btrfs_getxattr,
9548         .listxattr      = btrfs_listxattr,
9549         .removexattr    = btrfs_removexattr,
9550         .permission     = btrfs_permission,
9551         .get_acl        = btrfs_get_acl,
9552         .set_acl        = btrfs_set_acl,
9553         .update_time    = btrfs_update_time,
9554         .tmpfile        = btrfs_tmpfile,
9555 };
9556 static const struct inode_operations btrfs_dir_ro_inode_operations = {
9557         .lookup         = btrfs_lookup,
9558         .permission     = btrfs_permission,
9559         .get_acl        = btrfs_get_acl,
9560         .set_acl        = btrfs_set_acl,
9561         .update_time    = btrfs_update_time,
9562 };
9563
9564 static const struct file_operations btrfs_dir_file_operations = {
9565         .llseek         = generic_file_llseek,
9566         .read           = generic_read_dir,
9567         .iterate        = btrfs_real_readdir,
9568         .unlocked_ioctl = btrfs_ioctl,
9569 #ifdef CONFIG_COMPAT
9570         .compat_ioctl   = btrfs_ioctl,
9571 #endif
9572         .release        = btrfs_release_file,
9573         .fsync          = btrfs_sync_file,
9574 };
9575
9576 static struct extent_io_ops btrfs_extent_io_ops = {
9577         .fill_delalloc = run_delalloc_range,
9578         .submit_bio_hook = btrfs_submit_bio_hook,
9579         .merge_bio_hook = btrfs_merge_bio_hook,
9580         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
9581         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
9582         .writepage_start_hook = btrfs_writepage_start_hook,
9583         .set_bit_hook = btrfs_set_bit_hook,
9584         .clear_bit_hook = btrfs_clear_bit_hook,
9585         .merge_extent_hook = btrfs_merge_extent_hook,
9586         .split_extent_hook = btrfs_split_extent_hook,
9587 };
9588
9589 /*
9590  * btrfs doesn't support the bmap operation because swapfiles
9591  * use bmap to make a mapping of extents in the file.  They assume
9592  * these extents won't change over the life of the file and they
9593  * use the bmap result to do IO directly to the drive.
9594  *
9595  * the btrfs bmap call would return logical addresses that aren't
9596  * suitable for IO and they also will change frequently as COW
9597  * operations happen.  So, swapfile + btrfs == corruption.
9598  *
9599  * For now we're avoiding this by dropping bmap.
9600  */
9601 static const struct address_space_operations btrfs_aops = {
9602         .readpage       = btrfs_readpage,
9603         .writepage      = btrfs_writepage,
9604         .writepages     = btrfs_writepages,
9605         .readpages      = btrfs_readpages,
9606         .direct_IO      = btrfs_direct_IO,
9607         .invalidatepage = btrfs_invalidatepage,
9608         .releasepage    = btrfs_releasepage,
9609         .set_page_dirty = btrfs_set_page_dirty,
9610         .error_remove_page = generic_error_remove_page,
9611 };
9612
9613 static const struct address_space_operations btrfs_symlink_aops = {
9614         .readpage       = btrfs_readpage,
9615         .writepage      = btrfs_writepage,
9616         .invalidatepage = btrfs_invalidatepage,
9617         .releasepage    = btrfs_releasepage,
9618 };
9619
9620 static const struct inode_operations btrfs_file_inode_operations = {
9621         .getattr        = btrfs_getattr,
9622         .setattr        = btrfs_setattr,
9623         .setxattr       = btrfs_setxattr,
9624         .getxattr       = btrfs_getxattr,
9625         .listxattr      = btrfs_listxattr,
9626         .removexattr    = btrfs_removexattr,
9627         .permission     = btrfs_permission,
9628         .fiemap         = btrfs_fiemap,
9629         .get_acl        = btrfs_get_acl,
9630         .set_acl        = btrfs_set_acl,
9631         .update_time    = btrfs_update_time,
9632 };
9633 static const struct inode_operations btrfs_special_inode_operations = {
9634         .getattr        = btrfs_getattr,
9635         .setattr        = btrfs_setattr,
9636         .permission     = btrfs_permission,
9637         .setxattr       = btrfs_setxattr,
9638         .getxattr       = btrfs_getxattr,
9639         .listxattr      = btrfs_listxattr,
9640         .removexattr    = btrfs_removexattr,
9641         .get_acl        = btrfs_get_acl,
9642         .set_acl        = btrfs_set_acl,
9643         .update_time    = btrfs_update_time,
9644 };
9645 static const struct inode_operations btrfs_symlink_inode_operations = {
9646         .readlink       = generic_readlink,
9647         .follow_link    = page_follow_link_light,
9648         .put_link       = page_put_link,
9649         .getattr        = btrfs_getattr,
9650         .setattr        = btrfs_setattr,
9651         .permission     = btrfs_permission,
9652         .setxattr       = btrfs_setxattr,
9653         .getxattr       = btrfs_getxattr,
9654         .listxattr      = btrfs_listxattr,
9655         .removexattr    = btrfs_removexattr,
9656         .update_time    = btrfs_update_time,
9657 };
9658
9659 const struct dentry_operations btrfs_dentry_operations = {
9660         .d_delete       = btrfs_dentry_delete,
9661         .d_release      = btrfs_dentry_release,
9662 };