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                 btrfs_set_key_type(&key, 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 /*
 352  * we create compressed extents in two phases.  The first
 353  * phase compresses a range of pages that have already been
 354  * locked (both pages and state bits are locked).
 355  *
 356  * This is done inside an ordered work queue, and the compression
 357  * is spread across many cpus.  The actual IO submission is step
 358  * two, and the ordered work queue takes care of making sure that
 359  * happens in the same order things were put onto the queue by
 360  * writepages and friends.
 361  *
 362  * If this code finds it can't get good compression, it puts an
 363  * entry onto the work queue to write the uncompressed bytes.  This
 364  * makes sure that both compressed inodes and uncompressed inodes
 365  * are written in the same order that the flusher thread sent them
 366  * down.
 367  */
 368 static noinline int compress_file_range(struct inode *inode,
 369                                         struct page *locked_page,
 370                                         u64 start, u64 end,
 371                                         struct async_cow *async_cow,
 372                                         int *num_added)
 373 {
 374         struct btrfs_root *root = BTRFS_I(inode)->root;
 375         u64 num_bytes;
 376         u64 blocksize = root->sectorsize;
 377         u64 actual_end;
 378         u64 isize = i_size_read(inode);
 379         int ret = 0;
 380         struct page **pages = NULL;
 381         unsigned long nr_pages;
 382         unsigned long nr_pages_ret = 0;
 383         unsigned long total_compressed = 0;
 384         unsigned long total_in = 0;
 385         unsigned long max_compressed = 128 * 1024;
 386         unsigned long max_uncompressed = 128 * 1024;
 387         int i;
 388         int will_compress;
 389         int compress_type = root->fs_info->compress_type;
 390         int redirty = 0;
 391
 392         /* if this is a small write inside eof, kick off a defrag */
 393         if ((end - start + 1) < 16 * 1024 &&
 394             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 395                 btrfs_add_inode_defrag(NULL, inode);
 396
 397         /*
 398          * skip compression for a small file range(<=blocksize) that
 399          * isn't an inline extent, since it dosen't save disk space at all.
 400          */
 401         if ((end - start + 1) <= blocksize &&
 402             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 403                 goto cleanup_and_bail_uncompressed;
 404
 405         actual_end = min_t(u64, isize, end + 1);
 406 again:
 407         will_compress = 0;
 408         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 409         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 410
 411         /*
 412          * we don't want to send crud past the end of i_size through
 413          * compression, that's just a waste of CPU time.  So, if the
 414          * end of the file is before the start of our current
 415          * requested range of bytes, we bail out to the uncompressed
 416          * cleanup code that can deal with all of this.
 417          *
 418          * It isn't really the fastest way to fix things, but this is a
 419          * very uncommon corner.
 420          */
 421         if (actual_end <= start)
 422                 goto cleanup_and_bail_uncompressed;
 423
 424         total_compressed = actual_end - start;
 425
 426         /* we want to make sure that amount of ram required to uncompress
 427          * an extent is reasonable, so we limit the total size in ram
 428          * of a compressed extent to 128k.  This is a crucial number
 429          * because it also controls how easily we can spread reads across
 430          * cpus for decompression.
 431          *
 432          * We also want to make sure the amount of IO required to do
 433          * a random read is reasonably small, so we limit the size of
 434          * a compressed extent to 128k.
 435          */
 436         total_compressed = min(total_compressed, max_uncompressed);
 437         num_bytes = ALIGN(end - start + 1, blocksize);
 438         num_bytes = max(blocksize,  num_bytes);
 439         total_in = 0;
 440         ret = 0;
 441
 442         /*
 443          * we do compression for mount -o compress and when the
 444          * inode has not been flagged as nocompress.  This flag can
 445          * change at any time if we discover bad compression ratios.
 446          */
 447         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 448             (btrfs_test_opt(root, COMPRESS) ||
 449              (BTRFS_I(inode)->force_compress) ||
 450              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
 451                 WARN_ON(pages);
 452                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 453                 if (!pages) {
 454                         /* just bail out to the uncompressed code */
 455                         goto cont;
 456                 }
 457
 458                 if (BTRFS_I(inode)->force_compress)
 459                         compress_type = BTRFS_I(inode)->force_compress;
 460
 461                 /*
 462                  * we need to call clear_page_dirty_for_io on each
 463                  * page in the range.  Otherwise applications with the file
 464                  * mmap'd can wander in and change the page contents while
 465                  * we are compressing them.
 466                  *
 467                  * If the compression fails for any reason, we set the pages
 468                  * dirty again later on.
 469                  */
 470                 extent_range_clear_dirty_for_io(inode, start, end);
 471                 redirty = 1;
 472                 ret = btrfs_compress_pages(compress_type,
 473                                            inode->i_mapping, start,
 474                                            total_compressed, pages,
 475                                            nr_pages, &nr_pages_ret,
 476                                            &total_in,
 477                                            &total_compressed,
 478                                            max_compressed);
 479
 480                 if (!ret) {
 481                         unsigned long offset = total_compressed &
 482                                 (PAGE_CACHE_SIZE - 1);
 483                         struct page *page = pages[nr_pages_ret - 1];
 484                         char *kaddr;
 485
 486                         /* zero the tail end of the last page, we might be
 487                          * sending it down to disk
 488                          */
 489                         if (offset) {
 490                                 kaddr = kmap_atomic(page);
 491                                 memset(kaddr + offset, 0,
 492                                        PAGE_CACHE_SIZE - offset);
 493                                 kunmap_atomic(kaddr);
 494                         }
 495                         will_compress = 1;
 496                 }
 497         }
 498 cont:
 499         if (start == 0) {
 500                 /* lets try to make an inline extent */
 501                 if (ret || total_in < (actual_end - start)) {
 502                         /* we didn't compress the entire range, try
 503                          * to make an uncompressed inline extent.
 504                          */
 505                         ret = cow_file_range_inline(root, inode, start, end,
 506                                                     0, 0, NULL);
 507                 } else {
 508                         /* try making a compressed inline extent */
 509                         ret = cow_file_range_inline(root, inode, start, end,
 510                                                     total_compressed,
 511                                                     compress_type, pages);
 512                 }
 513                 if (ret <= 0) {
 514                         unsigned long clear_flags = EXTENT_DELALLOC |
 515                                 EXTENT_DEFRAG;
 516                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 517
 518                         /*
 519                          * inline extent creation worked or returned error,
 520                          * we don't need to create any more async work items.
 521                          * Unlock and free up our temp pages.
 522                          */
 523                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 524                                                      clear_flags, PAGE_UNLOCK |
 525                                                      PAGE_CLEAR_DIRTY |
 526                                                      PAGE_SET_WRITEBACK |
 527                                                      PAGE_END_WRITEBACK);
 528                         goto free_pages_out;
 529                 }
 530         }
 531
 532         if (will_compress) {
 533                 /*
 534                  * we aren't doing an inline extent round the compressed size
 535                  * up to a block size boundary so the allocator does sane
 536                  * things
 537                  */
 538                 total_compressed = ALIGN(total_compressed, blocksize);
 539
 540                 /*
 541                  * one last check to make sure the compression is really a
 542                  * win, compare the page count read with the blocks on disk
 543                  */
 544                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 545                 if (total_compressed >= total_in) {
 546                         will_compress = 0;
 547                 } else {
 548                         num_bytes = total_in;
 549                 }
 550         }
 551         if (!will_compress && pages) {
 552                 /*
 553                  * the compression code ran but failed to make things smaller,
 554                  * free any pages it allocated and our page pointer array
 555                  */
 556                 for (i = 0; i < nr_pages_ret; i++) {
 557                         WARN_ON(pages[i]->mapping);
 558                         page_cache_release(pages[i]);
 559                 }
 560                 kfree(pages);
 561                 pages = NULL;
 562                 total_compressed = 0;
 563                 nr_pages_ret = 0;
 564
 565                 /* flag the file so we don't compress in the future */
 566                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 567                     !(BTRFS_I(inode)->force_compress)) {
 568                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 569                 }
 570         }
 571         if (will_compress) {
 572                 *num_added += 1;
 573
 574                 /* the async work queues will take care of doing actual
 575                  * allocation on disk for these compressed pages,
 576                  * and will submit them to the elevator.
 577                  */
 578                 add_async_extent(async_cow, start, num_bytes,
 579                                  total_compressed, pages, nr_pages_ret,
 580                                  compress_type);
 581
 582                 if (start + num_bytes < end) {
 583                         start += num_bytes;
 584                         pages = NULL;
 585                         cond_resched();
 586                         goto again;
 587                 }
 588         } else {
 589 cleanup_and_bail_uncompressed:
 590                 /*
 591                  * No compression, but we still need to write the pages in
 592                  * the file we've been given so far.  redirty the locked
 593                  * page if it corresponds to our extent and set things up
 594                  * for the async work queue to run cow_file_range to do
 595                  * the normal delalloc dance
 596                  */
 597                 if (page_offset(locked_page) >= start &&
 598                     page_offset(locked_page) <= end) {
 599                         __set_page_dirty_nobuffers(locked_page);
 600                         /* unlocked later on in the async handlers */
 601                 }
 602                 if (redirty)
 603                         extent_range_redirty_for_io(inode, start, end);
 604                 add_async_extent(async_cow, start, end - start + 1,
 605                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 606                 *num_added += 1;
 607         }
 608
 609 out:
 610         return ret;
 611
 612 free_pages_out:
 613         for (i = 0; i < nr_pages_ret; i++) {
 614                 WARN_ON(pages[i]->mapping);
 615                 page_cache_release(pages[i]);
 616         }
 617         kfree(pages);
 618
 619         goto out;
 620 }
 621
 622 /*
 623  * phase two of compressed writeback.  This is the ordered portion
 624  * of the code, which only gets called in the order the work was
 625  * queued.  We walk all the async extents created by compress_file_range
 626  * and send them down to the disk.
 627  */
 628 static noinline int submit_compressed_extents(struct inode *inode,
 629                                               struct async_cow *async_cow)
 630 {
 631         struct async_extent *async_extent;
 632         u64 alloc_hint = 0;
 633         struct btrfs_key ins;
 634         struct extent_map *em;
 635         struct btrfs_root *root = BTRFS_I(inode)->root;
 636         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 637         struct extent_io_tree *io_tree;
 638         int ret = 0;
 639
 640         if (list_empty(&async_cow->extents))
 641                 return 0;
 642
 643 again:
 644         while (!list_empty(&async_cow->extents)) {
 645                 async_extent = list_entry(async_cow->extents.next,
 646                                           struct async_extent, list);
 647                 list_del(&async_extent->list);
 648
 649                 io_tree = &BTRFS_I(inode)->io_tree;
 650
 651 retry:
 652                 /* did the compression code fall back to uncompressed IO? */
 653                 if (!async_extent->pages) {
 654                         int page_started = 0;
 655                         unsigned long nr_written = 0;
 656
 657                         lock_extent(io_tree, async_extent->start,
 658                                          async_extent->start +
 659                                          async_extent->ram_size - 1);
 660
 661                         /* allocate blocks */
 662                         ret = cow_file_range(inode, async_cow->locked_page,
 663                                              async_extent->start,
 664                                              async_extent->start +
 665                                              async_extent->ram_size - 1,
 666                                              &page_started, &nr_written, 0);
 667
 668                         /* JDM XXX */
 669
 670                         /*
 671                          * if page_started, cow_file_range inserted an
 672                          * inline extent and took care of all the unlocking
 673                          * and IO for us.  Otherwise, we need to submit
 674                          * all those pages down to the drive.
 675                          */
 676                         if (!page_started && !ret)
 677                                 extent_write_locked_range(io_tree,
 678                                                   inode, async_extent->start,
 679                                                   async_extent->start +
 680                                                   async_extent->ram_size - 1,
 681                                                   btrfs_get_extent,
 682                                                   WB_SYNC_ALL);
 683                         else if (ret)
 684                                 unlock_page(async_cow->locked_page);
 685                         kfree(async_extent);
 686                         cond_resched();
 687                         continue;
 688                 }
 689
 690                 lock_extent(io_tree, async_extent->start,
 691                             async_extent->start + async_extent->ram_size - 1);
 692
 693                 ret = btrfs_reserve_extent(root,
 694                                            async_extent->compressed_size,
 695                                            async_extent->compressed_size,
 696                                            0, alloc_hint, &ins, 1, 1);
 697                 if (ret) {
 698                         int i;
 699
 700                         for (i = 0; i < async_extent->nr_pages; i++) {
 701                                 WARN_ON(async_extent->pages[i]->mapping);
 702                                 page_cache_release(async_extent->pages[i]);
 703                         }
 704                         kfree(async_extent->pages);
 705                         async_extent->nr_pages = 0;
 706                         async_extent->pages = NULL;
 707
 708                         if (ret == -ENOSPC) {
 709                                 unlock_extent(io_tree, async_extent->start,
 710                                               async_extent->start +
 711                                               async_extent->ram_size - 1);
 712
 713                                 /*
 714                                  * we need to redirty the pages if we decide to
 715                                  * fallback to uncompressed IO, otherwise we
 716                                  * will not submit these pages down to lower
 717                                  * layers.
 718                                  */
 719                                 extent_range_redirty_for_io(inode,
 720                                                 async_extent->start,
 721                                                 async_extent->start +
 722                                                 async_extent->ram_size - 1);
 723
 724                                 goto retry;
 725                         }
 726                         goto out_free;
 727                 }
 728
 729                 /*
 730                  * here we're doing allocation and writeback of the
 731                  * compressed pages
 732                  */
 733                 btrfs_drop_extent_cache(inode, async_extent->start,
 734                                         async_extent->start +
 735                                         async_extent->ram_size - 1, 0);
 736
 737                 em = alloc_extent_map();
 738                 if (!em) {
 739                         ret = -ENOMEM;
 740                         goto out_free_reserve;
 741                 }
 742                 em->start = async_extent->start;
 743                 em->len = async_extent->ram_size;
 744                 em->orig_start = em->start;
 745                 em->mod_start = em->start;
 746                 em->mod_len = em->len;
 747
 748                 em->block_start = ins.objectid;
 749                 em->block_len = ins.offset;
 750                 em->orig_block_len = ins.offset;
 751                 em->ram_bytes = async_extent->ram_size;
 752                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 753                 em->compress_type = async_extent->compress_type;
 754                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 755                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 756                 em->generation = -1;
 757
 758                 while (1) {
 759                         write_lock(&em_tree->lock);
 760                         ret = add_extent_mapping(em_tree, em, 1);
 761                         write_unlock(&em_tree->lock);
 762                         if (ret != -EEXIST) {
 763                                 free_extent_map(em);
 764                                 break;
 765                         }
 766                         btrfs_drop_extent_cache(inode, async_extent->start,
 767                                                 async_extent->start +
 768                                                 async_extent->ram_size - 1, 0);
 769                 }
 770
 771                 if (ret)
 772                         goto out_free_reserve;
 773
 774                 ret = btrfs_add_ordered_extent_compress(inode,
 775                                                 async_extent->start,
 776                                                 ins.objectid,
 777                                                 async_extent->ram_size,
 778                                                 ins.offset,
 779                                                 BTRFS_ORDERED_COMPRESSED,
 780                                                 async_extent->compress_type);
 781                 if (ret)
 782                         goto out_free_reserve;
 783
 784                 /*
 785                  * clear dirty, set writeback and unlock the pages.
 786                  */
 787                 extent_clear_unlock_delalloc(inode, async_extent->start,
 788                                 async_extent->start +
 789                                 async_extent->ram_size - 1,
 790                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 791                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 792                                 PAGE_SET_WRITEBACK);
 793                 ret = btrfs_submit_compressed_write(inode,
 794                                     async_extent->start,
 795                                     async_extent->ram_size,
 796                                     ins.objectid,
 797                                     ins.offset, async_extent->pages,
 798                                     async_extent->nr_pages);
 799                 alloc_hint = ins.objectid + ins.offset;
 800                 kfree(async_extent);
 801                 if (ret)
 802                         goto out;
 803                 cond_resched();
 804         }
 805         ret = 0;
 806 out:
 807         return ret;
 808 out_free_reserve:
 809         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 810 out_free:
 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                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 816                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 817                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 818         kfree(async_extent);
 819         goto again;
 820 }
 821
 822 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 823                                       u64 num_bytes)
 824 {
 825         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 826         struct extent_map *em;
 827         u64 alloc_hint = 0;
 828
 829         read_lock(&em_tree->lock);
 830         em = search_extent_mapping(em_tree, start, num_bytes);
 831         if (em) {
 832                 /*
 833                  * if block start isn't an actual block number then find the
 834                  * first block in this inode and use that as a hint.  If that
 835                  * block is also bogus then just don't worry about it.
 836                  */
 837                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 838                         free_extent_map(em);
 839                         em = search_extent_mapping(em_tree, 0, 0);
 840                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 841                                 alloc_hint = em->block_start;
 842                         if (em)
 843                                 free_extent_map(em);
 844                 } else {
 845                         alloc_hint = em->block_start;
 846                         free_extent_map(em);
 847                 }
 848         }
 849         read_unlock(&em_tree->lock);
 850
 851         return alloc_hint;
 852 }
 853
 854 /*
 855  * when extent_io.c finds a delayed allocation range in the file,
 856  * the call backs end up in this code.  The basic idea is to
 857  * allocate extents on disk for the range, and create ordered data structs
 858  * in ram to track those extents.
 859  *
 860  * locked_page is the page that writepage had locked already.  We use
 861  * it to make sure we don't do extra locks or unlocks.
 862  *
 863  * *page_started is set to one if we unlock locked_page and do everything
 864  * required to start IO on it.  It may be clean and already done with
 865  * IO when we return.
 866  */
 867 static noinline int cow_file_range(struct inode *inode,
 868                                    struct page *locked_page,
 869                                    u64 start, u64 end, int *page_started,
 870                                    unsigned long *nr_written,
 871                                    int unlock)
 872 {
 873         struct btrfs_root *root = BTRFS_I(inode)->root;
 874         u64 alloc_hint = 0;
 875         u64 num_bytes;
 876         unsigned long ram_size;
 877         u64 disk_num_bytes;
 878         u64 cur_alloc_size;
 879         u64 blocksize = root->sectorsize;
 880         struct btrfs_key ins;
 881         struct extent_map *em;
 882         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 883         int ret = 0;
 884
 885         if (btrfs_is_free_space_inode(inode)) {
 886                 WARN_ON_ONCE(1);
 887                 ret = -EINVAL;
 888                 goto out_unlock;
 889         }
 890
 891         num_bytes = ALIGN(end - start + 1, blocksize);
 892         num_bytes = max(blocksize,  num_bytes);
 893         disk_num_bytes = num_bytes;
 894
 895         /* if this is a small write inside eof, kick off defrag */
 896         if (num_bytes < 64 * 1024 &&
 897             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 898                 btrfs_add_inode_defrag(NULL, inode);
 899
 900         if (start == 0) {
 901                 /* lets try to make an inline extent */
 902                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 903                                             NULL);
 904                 if (ret == 0) {
 905                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 906                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 907                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 908                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 909                                      PAGE_END_WRITEBACK);
 910
 911                         *nr_written = *nr_written +
 912                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 913                         *page_started = 1;
 914                         goto out;
 915                 } else if (ret < 0) {
 916                         goto out_unlock;
 917                 }
 918         }
 919
 920         BUG_ON(disk_num_bytes >
 921                btrfs_super_total_bytes(root->fs_info->super_copy));
 922
 923         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 924         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 925
 926         while (disk_num_bytes > 0) {
 927                 unsigned long op;
 928
 929                 cur_alloc_size = disk_num_bytes;
 930                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 931                                            root->sectorsize, 0, alloc_hint,
 932                                            &ins, 1, 1);
 933                 if (ret < 0)
 934                         goto out_unlock;
 935
 936                 em = alloc_extent_map();
 937                 if (!em) {
 938                         ret = -ENOMEM;
 939                         goto out_reserve;
 940                 }
 941                 em->start = start;
 942                 em->orig_start = em->start;
 943                 ram_size = ins.offset;
 944                 em->len = ins.offset;
 945                 em->mod_start = em->start;
 946                 em->mod_len = em->len;
 947
 948                 em->block_start = ins.objectid;
 949                 em->block_len = ins.offset;
 950                 em->orig_block_len = ins.offset;
 951                 em->ram_bytes = ram_size;
 952                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 953                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 954                 em->generation = -1;
 955
 956                 while (1) {
 957                         write_lock(&em_tree->lock);
 958                         ret = add_extent_mapping(em_tree, em, 1);
 959                         write_unlock(&em_tree->lock);
 960                         if (ret != -EEXIST) {
 961                                 free_extent_map(em);
 962                                 break;
 963                         }
 964                         btrfs_drop_extent_cache(inode, start,
 965                                                 start + ram_size - 1, 0);
 966                 }
 967                 if (ret)
 968                         goto out_reserve;
 969
 970                 cur_alloc_size = ins.offset;
 971                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 972                                                ram_size, cur_alloc_size, 0);
 973                 if (ret)
 974                         goto out_reserve;
 975
 976                 if (root->root_key.objectid ==
 977                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 978                         ret = btrfs_reloc_clone_csums(inode, start,
 979                                                       cur_alloc_size);
 980                         if (ret)
 981                                 goto out_reserve;
 982                 }
 983
 984                 if (disk_num_bytes < cur_alloc_size)
 985                         break;
 986
 987                 /* we're not doing compressed IO, don't unlock the first
 988                  * page (which the caller expects to stay locked), don't
 989                  * clear any dirty bits and don't set any writeback bits
 990                  *
 991                  * Do set the Private2 bit so we know this page was properly
 992                  * setup for writepage
 993                  */
 994                 op = unlock ? PAGE_UNLOCK : 0;
 995                 op |= PAGE_SET_PRIVATE2;
 996
 997                 extent_clear_unlock_delalloc(inode, start,
 998                                              start + ram_size - 1, locked_page,
 999                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1000                                              op);
1001                 disk_num_bytes -= cur_alloc_size;
1002                 num_bytes -= cur_alloc_size;
1003                 alloc_hint = ins.objectid + ins.offset;
1004                 start += cur_alloc_size;
1005         }
1006 out:
1007         return ret;
1008
1009 out_reserve:
1010         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1011 out_unlock:
1012         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1013                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1014                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1015                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1016                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1017         goto out;
1018 }
1019
1020 /*
1021  * work queue call back to started compression on a file and pages
1022  */
1023 static noinline void async_cow_start(struct btrfs_work *work)
1024 {
1025         struct async_cow *async_cow;
1026         int num_added = 0;
1027         async_cow = container_of(work, struct async_cow, work);
1028
1029         compress_file_range(async_cow->inode, async_cow->locked_page,
1030                             async_cow->start, async_cow->end, async_cow,
1031                             &num_added);
1032         if (num_added == 0) {
1033                 btrfs_add_delayed_iput(async_cow->inode);
1034                 async_cow->inode = NULL;
1035         }
1036 }
1037
1038 /*
1039  * work queue call back to submit previously compressed pages
1040  */
1041 static noinline void async_cow_submit(struct btrfs_work *work)
1042 {
1043         struct async_cow *async_cow;
1044         struct btrfs_root *root;
1045         unsigned long nr_pages;
1046
1047         async_cow = container_of(work, struct async_cow, work);
1048
1049         root = async_cow->root;
1050         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1051                 PAGE_CACHE_SHIFT;
1052
1053         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1054             5 * 1024 * 1024 &&
1055             waitqueue_active(&root->fs_info->async_submit_wait))
1056                 wake_up(&root->fs_info->async_submit_wait);
1057
1058         if (async_cow->inode)
1059                 submit_compressed_extents(async_cow->inode, async_cow);
1060 }
1061
1062 static noinline void async_cow_free(struct btrfs_work *work)
1063 {
1064         struct async_cow *async_cow;
1065         async_cow = container_of(work, struct async_cow, work);
1066         if (async_cow->inode)
1067                 btrfs_add_delayed_iput(async_cow->inode);
1068         kfree(async_cow);
1069 }
1070
1071 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1072                                 u64 start, u64 end, int *page_started,
1073                                 unsigned long *nr_written)
1074 {
1075         struct async_cow *async_cow;
1076         struct btrfs_root *root = BTRFS_I(inode)->root;
1077         unsigned long nr_pages;
1078         u64 cur_end;
1079         int limit = 10 * 1024 * 1024;
1080
1081         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1082                          1, 0, NULL, GFP_NOFS);
1083         while (start < end) {
1084                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1085                 BUG_ON(!async_cow); /* -ENOMEM */
1086                 async_cow->inode = igrab(inode);
1087                 async_cow->root = root;
1088                 async_cow->locked_page = locked_page;
1089                 async_cow->start = start;
1090
1091                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
1092                         cur_end = end;
1093                 else
1094                         cur_end = min(end, start + 512 * 1024 - 1);
1095
1096                 async_cow->end = cur_end;
1097                 INIT_LIST_HEAD(&async_cow->extents);
1098
1099                 btrfs_init_work(&async_cow->work, async_cow_start,
1100                                 async_cow_submit, async_cow_free);
1101
1102                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1103                         PAGE_CACHE_SHIFT;
1104                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1105
1106                 btrfs_queue_work(root->fs_info->delalloc_workers,
1107                                  &async_cow->work);
1108
1109                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1110                         wait_event(root->fs_info->async_submit_wait,
1111                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1112                             limit));
1113                 }
1114
1115                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1116                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1117                         wait_event(root->fs_info->async_submit_wait,
1118                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1119                            0));
1120                 }
1121
1122                 *nr_written += nr_pages;
1123                 start = cur_end + 1;
1124         }
1125         *page_started = 1;
1126         return 0;
1127 }
1128
1129 static noinline int csum_exist_in_range(struct btrfs_root *root,
1130                                         u64 bytenr, u64 num_bytes)
1131 {
1132         int ret;
1133         struct btrfs_ordered_sum *sums;
1134         LIST_HEAD(list);
1135
1136         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1137                                        bytenr + num_bytes - 1, &list, 0);
1138         if (ret == 0 && list_empty(&list))
1139                 return 0;
1140
1141         while (!list_empty(&list)) {
1142                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1143                 list_del(&sums->list);
1144                 kfree(sums);
1145         }
1146         return 1;
1147 }
1148
1149 /*
1150  * when nowcow writeback call back.  This checks for snapshots or COW copies
1151  * of the extents that exist in the file, and COWs the file as required.
1152  *
1153  * If no cow copies or snapshots exist, we write directly to the existing
1154  * blocks on disk
1155  */
1156 static noinline int run_delalloc_nocow(struct inode *inode,
1157                                        struct page *locked_page,
1158                               u64 start, u64 end, int *page_started, int force,
1159                               unsigned long *nr_written)
1160 {
1161         struct btrfs_root *root = BTRFS_I(inode)->root;
1162         struct btrfs_trans_handle *trans;
1163         struct extent_buffer *leaf;
1164         struct btrfs_path *path;
1165         struct btrfs_file_extent_item *fi;
1166         struct btrfs_key found_key;
1167         u64 cow_start;
1168         u64 cur_offset;
1169         u64 extent_end;
1170         u64 extent_offset;
1171         u64 disk_bytenr;
1172         u64 num_bytes;
1173         u64 disk_num_bytes;
1174         u64 ram_bytes;
1175         int extent_type;
1176         int ret, err;
1177         int type;
1178         int nocow;
1179         int check_prev = 1;
1180         bool nolock;
1181         u64 ino = btrfs_ino(inode);
1182
1183         path = btrfs_alloc_path();
1184         if (!path) {
1185                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1186                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1187                                              EXTENT_DO_ACCOUNTING |
1188                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1189                                              PAGE_CLEAR_DIRTY |
1190                                              PAGE_SET_WRITEBACK |
1191                                              PAGE_END_WRITEBACK);
1192                 return -ENOMEM;
1193         }
1194
1195         nolock = btrfs_is_free_space_inode(inode);
1196
1197         if (nolock)
1198                 trans = btrfs_join_transaction_nolock(root);
1199         else
1200                 trans = btrfs_join_transaction(root);
1201
1202         if (IS_ERR(trans)) {
1203                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1204                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1205                                              EXTENT_DO_ACCOUNTING |
1206                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1207                                              PAGE_CLEAR_DIRTY |
1208                                              PAGE_SET_WRITEBACK |
1209                                              PAGE_END_WRITEBACK);
1210                 btrfs_free_path(path);
1211                 return PTR_ERR(trans);
1212         }
1213
1214         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1215
1216         cow_start = (u64)-1;
1217         cur_offset = start;
1218         while (1) {
1219                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1220                                                cur_offset, 0);
1221                 if (ret < 0)
1222                         goto error;
1223                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1224                         leaf = path->nodes[0];
1225                         btrfs_item_key_to_cpu(leaf, &found_key,
1226                                               path->slots[0] - 1);
1227                         if (found_key.objectid == ino &&
1228                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1229                                 path->slots[0]--;
1230                 }
1231                 check_prev = 0;
1232 next_slot:
1233                 leaf = path->nodes[0];
1234                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1235                         ret = btrfs_next_leaf(root, path);
1236                         if (ret < 0)
1237                                 goto error;
1238                         if (ret > 0)
1239                                 break;
1240                         leaf = path->nodes[0];
1241                 }
1242
1243                 nocow = 0;
1244                 disk_bytenr = 0;
1245                 num_bytes = 0;
1246                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1247
1248                 if (found_key.objectid > ino ||
1249                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1250                     found_key.offset > end)
1251                         break;
1252
1253                 if (found_key.offset > cur_offset) {
1254                         extent_end = found_key.offset;
1255                         extent_type = 0;
1256                         goto out_check;
1257                 }
1258
1259                 fi = btrfs_item_ptr(leaf, path->slots[0],
1260                                     struct btrfs_file_extent_item);
1261                 extent_type = btrfs_file_extent_type(leaf, fi);
1262
1263                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1264                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1265                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1266                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1267                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1268                         extent_end = found_key.offset +
1269                                 btrfs_file_extent_num_bytes(leaf, fi);
1270                         disk_num_bytes =
1271                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1272                         if (extent_end <= start) {
1273                                 path->slots[0]++;
1274                                 goto next_slot;
1275                         }
1276                         if (disk_bytenr == 0)
1277                                 goto out_check;
1278                         if (btrfs_file_extent_compression(leaf, fi) ||
1279                             btrfs_file_extent_encryption(leaf, fi) ||
1280                             btrfs_file_extent_other_encoding(leaf, fi))
1281                                 goto out_check;
1282                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1283                                 goto out_check;
1284                         if (btrfs_extent_readonly(root, disk_bytenr))
1285                                 goto out_check;
1286                         if (btrfs_cross_ref_exist(trans, root, ino,
1287                                                   found_key.offset -
1288                                                   extent_offset, disk_bytenr))
1289                                 goto out_check;
1290                         disk_bytenr += extent_offset;
1291                         disk_bytenr += cur_offset - found_key.offset;
1292                         num_bytes = min(end + 1, extent_end) - cur_offset;
1293                         /*
1294                          * if there are pending snapshots for this root,
1295                          * we fall into common COW way.
1296                          */
1297                         if (!nolock) {
1298                                 err = btrfs_start_nocow_write(root);
1299                                 if (!err)
1300                                         goto out_check;
1301                         }
1302                         /*
1303                          * force cow if csum exists in the range.
1304                          * this ensure that csum for a given extent are
1305                          * either valid or do not exist.
1306                          */
1307                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1308                                 goto out_check;
1309                         nocow = 1;
1310                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1311                         extent_end = found_key.offset +
1312                                 btrfs_file_extent_inline_len(leaf,
1313                                                      path->slots[0], fi);
1314                         extent_end = ALIGN(extent_end, root->sectorsize);
1315                 } else {
1316                         BUG_ON(1);
1317                 }
1318 out_check:
1319                 if (extent_end <= start) {
1320                         path->slots[0]++;
1321                         if (!nolock && nocow)
1322                                 btrfs_end_nocow_write(root);
1323                         goto next_slot;
1324                 }
1325                 if (!nocow) {
1326                         if (cow_start == (u64)-1)
1327                                 cow_start = cur_offset;
1328                         cur_offset = extent_end;
1329                         if (cur_offset > end)
1330                                 break;
1331                         path->slots[0]++;
1332                         goto next_slot;
1333                 }
1334
1335                 btrfs_release_path(path);
1336                 if (cow_start != (u64)-1) {
1337                         ret = cow_file_range(inode, locked_page,
1338                                              cow_start, found_key.offset - 1,
1339                                              page_started, nr_written, 1);
1340                         if (ret) {
1341                                 if (!nolock && nocow)
1342                                         btrfs_end_nocow_write(root);
1343                                 goto error;
1344                         }
1345                         cow_start = (u64)-1;
1346                 }
1347
1348                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1349                         struct extent_map *em;
1350                         struct extent_map_tree *em_tree;
1351                         em_tree = &BTRFS_I(inode)->extent_tree;
1352                         em = alloc_extent_map();
1353                         BUG_ON(!em); /* -ENOMEM */
1354                         em->start = cur_offset;
1355                         em->orig_start = found_key.offset - extent_offset;
1356                         em->len = num_bytes;
1357                         em->block_len = num_bytes;
1358                         em->block_start = disk_bytenr;
1359                         em->orig_block_len = disk_num_bytes;
1360                         em->ram_bytes = ram_bytes;
1361                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1362                         em->mod_start = em->start;
1363                         em->mod_len = em->len;
1364                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1365                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1366                         em->generation = -1;
1367                         while (1) {
1368                                 write_lock(&em_tree->lock);
1369                                 ret = add_extent_mapping(em_tree, em, 1);
1370                                 write_unlock(&em_tree->lock);
1371                                 if (ret != -EEXIST) {
1372                                         free_extent_map(em);
1373                                         break;
1374                                 }
1375                                 btrfs_drop_extent_cache(inode, em->start,
1376                                                 em->start + em->len - 1, 0);
1377                         }
1378                         type = BTRFS_ORDERED_PREALLOC;
1379                 } else {
1380                         type = BTRFS_ORDERED_NOCOW;
1381                 }
1382
1383                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1384                                                num_bytes, num_bytes, type);
1385                 BUG_ON(ret); /* -ENOMEM */
1386
1387                 if (root->root_key.objectid ==
1388                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1389                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1390                                                       num_bytes);
1391                         if (ret) {
1392                                 if (!nolock && nocow)
1393                                         btrfs_end_nocow_write(root);
1394                                 goto error;
1395                         }
1396                 }
1397
1398                 extent_clear_unlock_delalloc(inode, cur_offset,
1399                                              cur_offset + num_bytes - 1,
1400                                              locked_page, EXTENT_LOCKED |
1401                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1402                                              PAGE_SET_PRIVATE2);
1403                 if (!nolock && nocow)
1404                         btrfs_end_nocow_write(root);
1405                 cur_offset = extent_end;
1406                 if (cur_offset > end)
1407                         break;
1408         }
1409         btrfs_release_path(path);
1410
1411         if (cur_offset <= end && cow_start == (u64)-1) {
1412                 cow_start = cur_offset;
1413                 cur_offset = end;
1414         }
1415
1416         if (cow_start != (u64)-1) {
1417                 ret = cow_file_range(inode, locked_page, cow_start, end,
1418                                      page_started, nr_written, 1);
1419                 if (ret)
1420                         goto error;
1421         }
1422
1423 error:
1424         err = btrfs_end_transaction(trans, root);
1425         if (!ret)
1426                 ret = err;
1427
1428         if (ret && cur_offset < end)
1429                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1430                                              locked_page, EXTENT_LOCKED |
1431                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1432                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1433                                              PAGE_CLEAR_DIRTY |
1434                                              PAGE_SET_WRITEBACK |
1435                                              PAGE_END_WRITEBACK);
1436         btrfs_free_path(path);
1437         return ret;
1438 }
1439
1440 /*
1441  * extent_io.c call back to do delayed allocation processing
1442  */
1443 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1444                               u64 start, u64 end, int *page_started,
1445                               unsigned long *nr_written)
1446 {
1447         int ret;
1448         struct btrfs_root *root = BTRFS_I(inode)->root;
1449
1450         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {
1451                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1452                                          page_started, 1, nr_written);
1453         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {
1454                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1455                                          page_started, 0, nr_written);
1456         } else if (!btrfs_test_opt(root, COMPRESS) &&
1457                    !(BTRFS_I(inode)->force_compress) &&
1458                    !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS)) {
1459                 ret = cow_file_range(inode, locked_page, start, end,
1460                                       page_started, nr_written, 1);
1461         } else {
1462                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1463                         &BTRFS_I(inode)->runtime_flags);
1464                 ret = cow_file_range_async(inode, locked_page, start, end,
1465                                            page_started, nr_written);
1466         }
1467         return ret;
1468 }
1469
1470 static void btrfs_split_extent_hook(struct inode *inode,
1471                                     struct extent_state *orig, u64 split)
1472 {
1473         /* not delalloc, ignore it */
1474         if (!(orig->state & EXTENT_DELALLOC))
1475                 return;
1476
1477         spin_lock(&BTRFS_I(inode)->lock);
1478         BTRFS_I(inode)->outstanding_extents++;
1479         spin_unlock(&BTRFS_I(inode)->lock);
1480 }
1481
1482 /*
1483  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1484  * extents so we can keep track of new extents that are just merged onto old
1485  * extents, such as when we are doing sequential writes, so we can properly
1486  * account for the metadata space we'll need.
1487  */
1488 static void btrfs_merge_extent_hook(struct inode *inode,
1489                                     struct extent_state *new,
1490                                     struct extent_state *other)
1491 {
1492         /* not delalloc, ignore it */
1493         if (!(other->state & EXTENT_DELALLOC))
1494                 return;
1495
1496         spin_lock(&BTRFS_I(inode)->lock);
1497         BTRFS_I(inode)->outstanding_extents--;
1498         spin_unlock(&BTRFS_I(inode)->lock);
1499 }
1500
1501 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1502                                       struct inode *inode)
1503 {
1504         spin_lock(&root->delalloc_lock);
1505         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1506                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1507                               &root->delalloc_inodes);
1508                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1509                         &BTRFS_I(inode)->runtime_flags);
1510                 root->nr_delalloc_inodes++;
1511                 if (root->nr_delalloc_inodes == 1) {
1512                         spin_lock(&root->fs_info->delalloc_root_lock);
1513                         BUG_ON(!list_empty(&root->delalloc_root));
1514                         list_add_tail(&root->delalloc_root,
1515                                       &root->fs_info->delalloc_roots);
1516                         spin_unlock(&root->fs_info->delalloc_root_lock);
1517                 }
1518         }
1519         spin_unlock(&root->delalloc_lock);
1520 }
1521
1522 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1523                                      struct inode *inode)
1524 {
1525         spin_lock(&root->delalloc_lock);
1526         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1527                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1528                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1529                           &BTRFS_I(inode)->runtime_flags);
1530                 root->nr_delalloc_inodes--;
1531                 if (!root->nr_delalloc_inodes) {
1532                         spin_lock(&root->fs_info->delalloc_root_lock);
1533                         BUG_ON(list_empty(&root->delalloc_root));
1534                         list_del_init(&root->delalloc_root);
1535                         spin_unlock(&root->fs_info->delalloc_root_lock);
1536                 }
1537         }
1538         spin_unlock(&root->delalloc_lock);
1539 }
1540
1541 /*
1542  * extent_io.c set_bit_hook, used to track delayed allocation
1543  * bytes in this file, and to maintain the list of inodes that
1544  * have pending delalloc work to be done.
1545  */
1546 static void btrfs_set_bit_hook(struct inode *inode,
1547                                struct extent_state *state, unsigned long *bits)
1548 {
1549
1550         /*
1551          * set_bit and clear bit hooks normally require _irqsave/restore
1552          * but in this case, we are only testing for the DELALLOC
1553          * bit, which is only set or cleared with irqs on
1554          */
1555         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1556                 struct btrfs_root *root = BTRFS_I(inode)->root;
1557                 u64 len = state->end + 1 - state->start;
1558                 bool do_list = !btrfs_is_free_space_inode(inode);
1559
1560                 if (*bits & EXTENT_FIRST_DELALLOC) {
1561                         *bits &= ~EXTENT_FIRST_DELALLOC;
1562                 } else {
1563                         spin_lock(&BTRFS_I(inode)->lock);
1564                         BTRFS_I(inode)->outstanding_extents++;
1565                         spin_unlock(&BTRFS_I(inode)->lock);
1566                 }
1567
1568                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1569                                      root->fs_info->delalloc_batch);
1570                 spin_lock(&BTRFS_I(inode)->lock);
1571                 BTRFS_I(inode)->delalloc_bytes += len;
1572                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1573                                          &BTRFS_I(inode)->runtime_flags))
1574                         btrfs_add_delalloc_inodes(root, inode);
1575                 spin_unlock(&BTRFS_I(inode)->lock);
1576         }
1577 }
1578
1579 /*
1580  * extent_io.c clear_bit_hook, see set_bit_hook for why
1581  */
1582 static void btrfs_clear_bit_hook(struct inode *inode,
1583                                  struct extent_state *state,
1584                                  unsigned long *bits)
1585 {
1586         /*
1587          * set_bit and clear bit hooks normally require _irqsave/restore
1588          * but in this case, we are only testing for the DELALLOC
1589          * bit, which is only set or cleared with irqs on
1590          */
1591         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1592                 struct btrfs_root *root = BTRFS_I(inode)->root;
1593                 u64 len = state->end + 1 - state->start;
1594                 bool do_list = !btrfs_is_free_space_inode(inode);
1595
1596                 if (*bits & EXTENT_FIRST_DELALLOC) {
1597                         *bits &= ~EXTENT_FIRST_DELALLOC;
1598                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1599                         spin_lock(&BTRFS_I(inode)->lock);
1600                         BTRFS_I(inode)->outstanding_extents--;
1601                         spin_unlock(&BTRFS_I(inode)->lock);
1602                 }
1603
1604                 /*
1605                  * We don't reserve metadata space for space cache inodes so we
1606                  * don't need to call dellalloc_release_metadata if there is an
1607                  * error.
1608                  */
1609                 if (*bits & EXTENT_DO_ACCOUNTING &&
1610                     root != root->fs_info->tree_root)
1611                         btrfs_delalloc_release_metadata(inode, len);
1612
1613                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1614                     && do_list && !(state->state & EXTENT_NORESERVE))
1615                         btrfs_free_reserved_data_space(inode, len);
1616
1617                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1618                                      root->fs_info->delalloc_batch);
1619                 spin_lock(&BTRFS_I(inode)->lock);
1620                 BTRFS_I(inode)->delalloc_bytes -= len;
1621                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1622                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1623                              &BTRFS_I(inode)->runtime_flags))
1624                         btrfs_del_delalloc_inode(root, inode);
1625                 spin_unlock(&BTRFS_I(inode)->lock);
1626         }
1627 }
1628
1629 /*
1630  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1631  * we don't create bios that span stripes or chunks
1632  */
1633 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1634                          size_t size, struct bio *bio,
1635                          unsigned long bio_flags)
1636 {
1637         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1638         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1639         u64 length = 0;
1640         u64 map_length;
1641         int ret;
1642
1643         if (bio_flags & EXTENT_BIO_COMPRESSED)
1644                 return 0;
1645
1646         length = bio->bi_iter.bi_size;
1647         map_length = length;
1648         ret = btrfs_map_block(root->fs_info, rw, logical,
1649                               &map_length, NULL, 0);
1650         /* Will always return 0 with map_multi == NULL */
1651         BUG_ON(ret < 0);
1652         if (map_length < length + size)
1653                 return 1;
1654         return 0;
1655 }
1656
1657 /*
1658  * in order to insert checksums into the metadata in large chunks,
1659  * we wait until bio submission time.   All the pages in the bio are
1660  * checksummed and sums are attached onto the ordered extent record.
1661  *
1662  * At IO completion time the cums attached on the ordered extent record
1663  * are inserted into the btree
1664  */
1665 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1666                                     struct bio *bio, int mirror_num,
1667                                     unsigned long bio_flags,
1668                                     u64 bio_offset)
1669 {
1670         struct btrfs_root *root = BTRFS_I(inode)->root;
1671         int ret = 0;
1672
1673         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1674         BUG_ON(ret); /* -ENOMEM */
1675         return 0;
1676 }
1677
1678 /*
1679  * in order to insert checksums into the metadata in large chunks,
1680  * we wait until bio submission time.   All the pages in the bio are
1681  * checksummed and sums are attached onto the ordered extent record.
1682  *
1683  * At IO completion time the cums attached on the ordered extent record
1684  * are inserted into the btree
1685  */
1686 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1687                           int mirror_num, unsigned long bio_flags,
1688                           u64 bio_offset)
1689 {
1690         struct btrfs_root *root = BTRFS_I(inode)->root;
1691         int ret;
1692
1693         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1694         if (ret)
1695                 bio_endio(bio, ret);
1696         return ret;
1697 }
1698
1699 /*
1700  * extent_io.c submission hook. This does the right thing for csum calculation
1701  * on write, or reading the csums from the tree before a read
1702  */
1703 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1704                           int mirror_num, unsigned long bio_flags,
1705                           u64 bio_offset)
1706 {
1707         struct btrfs_root *root = BTRFS_I(inode)->root;
1708         int ret = 0;
1709         int skip_sum;
1710         int metadata = 0;
1711         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1712
1713         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1714
1715         if (btrfs_is_free_space_inode(inode))
1716                 metadata = 2;
1717
1718         if (!(rw & REQ_WRITE)) {
1719                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1720                 if (ret)
1721                         goto out;
1722
1723                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1724                         ret = btrfs_submit_compressed_read(inode, bio,
1725                                                            mirror_num,
1726                                                            bio_flags);
1727                         goto out;
1728                 } else if (!skip_sum) {
1729                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1730                         if (ret)
1731                                 goto out;
1732                 }
1733                 goto mapit;
1734         } else if (async && !skip_sum) {
1735                 /* csum items have already been cloned */
1736                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1737                         goto mapit;
1738                 /* we're doing a write, do the async checksumming */
1739                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1740                                    inode, rw, bio, mirror_num,
1741                                    bio_flags, bio_offset,
1742                                    __btrfs_submit_bio_start,
1743                                    __btrfs_submit_bio_done);
1744                 goto out;
1745         } else if (!skip_sum) {
1746                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1747                 if (ret)
1748                         goto out;
1749         }
1750
1751 mapit:
1752         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1753
1754 out:
1755         if (ret < 0)
1756                 bio_endio(bio, ret);
1757         return ret;
1758 }
1759
1760 /*
1761  * given a list of ordered sums record them in the inode.  This happens
1762  * at IO completion time based on sums calculated at bio submission time.
1763  */
1764 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1765                              struct inode *inode, u64 file_offset,
1766                              struct list_head *list)
1767 {
1768         struct btrfs_ordered_sum *sum;
1769
1770         list_for_each_entry(sum, list, list) {
1771                 trans->adding_csums = 1;
1772                 btrfs_csum_file_blocks(trans,
1773                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1774                 trans->adding_csums = 0;
1775         }
1776         return 0;
1777 }
1778
1779 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1780                               struct extent_state **cached_state)
1781 {
1782         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1783         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1784                                    cached_state, GFP_NOFS);
1785 }
1786
1787 /* see btrfs_writepage_start_hook for details on why this is required */
1788 struct btrfs_writepage_fixup {
1789         struct page *page;
1790         struct btrfs_work work;
1791 };
1792
1793 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1794 {
1795         struct btrfs_writepage_fixup *fixup;
1796         struct btrfs_ordered_extent *ordered;
1797         struct extent_state *cached_state = NULL;
1798         struct page *page;
1799         struct inode *inode;
1800         u64 page_start;
1801         u64 page_end;
1802         int ret;
1803
1804         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1805         page = fixup->page;
1806 again:
1807         lock_page(page);
1808         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1809                 ClearPageChecked(page);
1810                 goto out_page;
1811         }
1812
1813         inode = page->mapping->host;
1814         page_start = page_offset(page);
1815         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1816
1817         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1818                          &cached_state);
1819
1820         /* already ordered? We're done */
1821         if (PagePrivate2(page))
1822                 goto out;
1823
1824         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1825         if (ordered) {
1826                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1827                                      page_end, &cached_state, GFP_NOFS);
1828                 unlock_page(page);
1829                 btrfs_start_ordered_extent(inode, ordered, 1);
1830                 btrfs_put_ordered_extent(ordered);
1831                 goto again;
1832         }
1833
1834         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1835         if (ret) {
1836                 mapping_set_error(page->mapping, ret);
1837                 end_extent_writepage(page, ret, page_start, page_end);
1838                 ClearPageChecked(page);
1839                 goto out;
1840          }
1841
1842         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1843         ClearPageChecked(page);
1844         set_page_dirty(page);
1845 out:
1846         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1847                              &cached_state, GFP_NOFS);
1848 out_page:
1849         unlock_page(page);
1850         page_cache_release(page);
1851         kfree(fixup);
1852 }
1853
1854 /*
1855  * There are a few paths in the higher layers of the kernel that directly
1856  * set the page dirty bit without asking the filesystem if it is a
1857  * good idea.  This causes problems because we want to make sure COW
1858  * properly happens and the data=ordered rules are followed.
1859  *
1860  * In our case any range that doesn't have the ORDERED bit set
1861  * hasn't been properly setup for IO.  We kick off an async process
1862  * to fix it up.  The async helper will wait for ordered extents, set
1863  * the delalloc bit and make it safe to write the page.
1864  */
1865 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1866 {
1867         struct inode *inode = page->mapping->host;
1868         struct btrfs_writepage_fixup *fixup;
1869         struct btrfs_root *root = BTRFS_I(inode)->root;
1870
1871         /* this page is properly in the ordered list */
1872         if (TestClearPagePrivate2(page))
1873                 return 0;
1874
1875         if (PageChecked(page))
1876                 return -EAGAIN;
1877
1878         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1879         if (!fixup)
1880                 return -EAGAIN;
1881
1882         SetPageChecked(page);
1883         page_cache_get(page);
1884         btrfs_init_work(&fixup->work, btrfs_writepage_fixup_worker, NULL, NULL);
1885         fixup->page = page;
1886         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
1887         return -EBUSY;
1888 }
1889
1890 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1891                                        struct inode *inode, u64 file_pos,
1892                                        u64 disk_bytenr, u64 disk_num_bytes,
1893                                        u64 num_bytes, u64 ram_bytes,
1894                                        u8 compression, u8 encryption,
1895                                        u16 other_encoding, int extent_type)
1896 {
1897         struct btrfs_root *root = BTRFS_I(inode)->root;
1898         struct btrfs_file_extent_item *fi;
1899         struct btrfs_path *path;
1900         struct extent_buffer *leaf;
1901         struct btrfs_key ins;
1902         int extent_inserted = 0;
1903         int ret;
1904
1905         path = btrfs_alloc_path();
1906         if (!path)
1907                 return -ENOMEM;
1908
1909         /*
1910          * we may be replacing one extent in the tree with another.
1911          * The new extent is pinned in the extent map, and we don't want
1912          * to drop it from the cache until it is completely in the btree.
1913          *
1914          * So, tell btrfs_drop_extents to leave this extent in the cache.
1915          * the caller is expected to unpin it and allow it to be merged
1916          * with the others.
1917          */
1918         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
1919                                    file_pos + num_bytes, NULL, 0,
1920                                    1, sizeof(*fi), &extent_inserted);
1921         if (ret)
1922                 goto out;
1923
1924         if (!extent_inserted) {
1925                 ins.objectid = btrfs_ino(inode);
1926                 ins.offset = file_pos;
1927                 ins.type = BTRFS_EXTENT_DATA_KEY;
1928
1929                 path->leave_spinning = 1;
1930                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
1931                                               sizeof(*fi));
1932                 if (ret)
1933                         goto out;
1934         }
1935         leaf = path->nodes[0];
1936         fi = btrfs_item_ptr(leaf, path->slots[0],
1937                             struct btrfs_file_extent_item);
1938         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1939         btrfs_set_file_extent_type(leaf, fi, extent_type);
1940         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1941         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1942         btrfs_set_file_extent_offset(leaf, fi, 0);
1943         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1944         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1945         btrfs_set_file_extent_compression(leaf, fi, compression);
1946         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1947         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1948
1949         btrfs_mark_buffer_dirty(leaf);
1950         btrfs_release_path(path);
1951
1952         inode_add_bytes(inode, num_bytes);
1953
1954         ins.objectid = disk_bytenr;
1955         ins.offset = disk_num_bytes;
1956         ins.type = BTRFS_EXTENT_ITEM_KEY;
1957         ret = btrfs_alloc_reserved_file_extent(trans, root,
1958                                         root->root_key.objectid,
1959                                         btrfs_ino(inode), file_pos, &ins);
1960 out:
1961         btrfs_free_path(path);
1962
1963         return ret;
1964 }
1965
1966 /* snapshot-aware defrag */
1967 struct sa_defrag_extent_backref {
1968         struct rb_node node;
1969         struct old_sa_defrag_extent *old;
1970         u64 root_id;
1971         u64 inum;
1972         u64 file_pos;
1973         u64 extent_offset;
1974         u64 num_bytes;
1975         u64 generation;
1976 };
1977
1978 struct old_sa_defrag_extent {
1979         struct list_head list;
1980         struct new_sa_defrag_extent *new;
1981
1982         u64 extent_offset;
1983         u64 bytenr;
1984         u64 offset;
1985         u64 len;
1986         int count;
1987 };
1988
1989 struct new_sa_defrag_extent {
1990         struct rb_root root;
1991         struct list_head head;
1992         struct btrfs_path *path;
1993         struct inode *inode;
1994         u64 file_pos;
1995         u64 len;
1996         u64 bytenr;
1997         u64 disk_len;
1998         u8 compress_type;
1999 };
2000
2001 static int backref_comp(struct sa_defrag_extent_backref *b1,
2002                         struct sa_defrag_extent_backref *b2)
2003 {
2004         if (b1->root_id < b2->root_id)
2005                 return -1;
2006         else if (b1->root_id > b2->root_id)
2007                 return 1;
2008
2009         if (b1->inum < b2->inum)
2010                 return -1;
2011         else if (b1->inum > b2->inum)
2012                 return 1;
2013
2014         if (b1->file_pos < b2->file_pos)
2015                 return -1;
2016         else if (b1->file_pos > b2->file_pos)
2017                 return 1;
2018
2019         /*
2020          * [------------------------------] ===> (a range of space)
2021          *     |<--->|   |<---->| =============> (fs/file tree A)
2022          * |<---------------------------->| ===> (fs/file tree B)
2023          *
2024          * A range of space can refer to two file extents in one tree while
2025          * refer to only one file extent in another tree.
2026          *
2027          * So we may process a disk offset more than one time(two extents in A)
2028          * and locate at the same extent(one extent in B), then insert two same
2029          * backrefs(both refer to the extent in B).
2030          */
2031         return 0;
2032 }
2033
2034 static void backref_insert(struct rb_root *root,
2035                            struct sa_defrag_extent_backref *backref)
2036 {
2037         struct rb_node **p = &root->rb_node;
2038         struct rb_node *parent = NULL;
2039         struct sa_defrag_extent_backref *entry;
2040         int ret;
2041
2042         while (*p) {
2043                 parent = *p;
2044                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2045
2046                 ret = backref_comp(backref, entry);
2047                 if (ret < 0)
2048                         p = &(*p)->rb_left;
2049                 else
2050                         p = &(*p)->rb_right;
2051         }
2052
2053         rb_link_node(&backref->node, parent, p);
2054         rb_insert_color(&backref->node, root);
2055 }
2056
2057 /*
2058  * Note the backref might has changed, and in this case we just return 0.
2059  */
2060 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2061                                        void *ctx)
2062 {
2063         struct btrfs_file_extent_item *extent;
2064         struct btrfs_fs_info *fs_info;
2065         struct old_sa_defrag_extent *old = ctx;
2066         struct new_sa_defrag_extent *new = old->new;
2067         struct btrfs_path *path = new->path;
2068         struct btrfs_key key;
2069         struct btrfs_root *root;
2070         struct sa_defrag_extent_backref *backref;
2071         struct extent_buffer *leaf;
2072         struct inode *inode = new->inode;
2073         int slot;
2074         int ret;
2075         u64 extent_offset;
2076         u64 num_bytes;
2077
2078         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2079             inum == btrfs_ino(inode))
2080                 return 0;
2081
2082         key.objectid = root_id;
2083         key.type = BTRFS_ROOT_ITEM_KEY;
2084         key.offset = (u64)-1;
2085
2086         fs_info = BTRFS_I(inode)->root->fs_info;
2087         root = btrfs_read_fs_root_no_name(fs_info, &key);
2088         if (IS_ERR(root)) {
2089                 if (PTR_ERR(root) == -ENOENT)
2090                         return 0;
2091                 WARN_ON(1);
2092                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2093                          inum, offset, root_id);
2094                 return PTR_ERR(root);
2095         }
2096
2097         key.objectid = inum;
2098         key.type = BTRFS_EXTENT_DATA_KEY;
2099         if (offset > (u64)-1 << 32)
2100                 key.offset = 0;
2101         else
2102                 key.offset = offset;
2103
2104         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2105         if (WARN_ON(ret < 0))
2106                 return ret;
2107         ret = 0;
2108
2109         while (1) {
2110                 cond_resched();
2111
2112                 leaf = path->nodes[0];
2113                 slot = path->slots[0];
2114
2115                 if (slot >= btrfs_header_nritems(leaf)) {
2116                         ret = btrfs_next_leaf(root, path);
2117                         if (ret < 0) {
2118                                 goto out;
2119                         } else if (ret > 0) {
2120                                 ret = 0;
2121                                 goto out;
2122                         }
2123                         continue;
2124                 }
2125
2126                 path->slots[0]++;
2127
2128                 btrfs_item_key_to_cpu(leaf, &key, slot);
2129
2130                 if (key.objectid > inum)
2131                         goto out;
2132
2133                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2134                         continue;
2135
2136                 extent = btrfs_item_ptr(leaf, slot,
2137                                         struct btrfs_file_extent_item);
2138
2139                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2140                         continue;
2141
2142                 /*
2143                  * 'offset' refers to the exact key.offset,
2144                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2145                  * (key.offset - extent_offset).
2146                  */
2147                 if (key.offset != offset)
2148                         continue;
2149
2150                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2151                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2152
2153                 if (extent_offset >= old->extent_offset + old->offset +
2154                     old->len || extent_offset + num_bytes <=
2155                     old->extent_offset + old->offset)
2156                         continue;
2157                 break;
2158         }
2159
2160         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2161         if (!backref) {
2162                 ret = -ENOENT;
2163                 goto out;
2164         }
2165
2166         backref->root_id = root_id;
2167         backref->inum = inum;
2168         backref->file_pos = offset;
2169         backref->num_bytes = num_bytes;
2170         backref->extent_offset = extent_offset;
2171         backref->generation = btrfs_file_extent_generation(leaf, extent);
2172         backref->old = old;
2173         backref_insert(&new->root, backref);
2174         old->count++;
2175 out:
2176         btrfs_release_path(path);
2177         WARN_ON(ret);
2178         return ret;
2179 }
2180
2181 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2182                                    struct new_sa_defrag_extent *new)
2183 {
2184         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2185         struct old_sa_defrag_extent *old, *tmp;
2186         int ret;
2187
2188         new->path = path;
2189
2190         list_for_each_entry_safe(old, tmp, &new->head, list) {
2191                 ret = iterate_inodes_from_logical(old->bytenr +
2192                                                   old->extent_offset, fs_info,
2193                                                   path, record_one_backref,
2194                                                   old);
2195                 if (ret < 0 && ret != -ENOENT)
2196                         return false;
2197
2198                 /* no backref to be processed for this extent */
2199                 if (!old->count) {
2200                         list_del(&old->list);
2201                         kfree(old);
2202                 }
2203         }
2204
2205         if (list_empty(&new->head))
2206                 return false;
2207
2208         return true;
2209 }
2210
2211 static int relink_is_mergable(struct extent_buffer *leaf,
2212                               struct btrfs_file_extent_item *fi,
2213                               struct new_sa_defrag_extent *new)
2214 {
2215         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2216                 return 0;
2217
2218         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2219                 return 0;
2220
2221         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2222                 return 0;
2223
2224         if (btrfs_file_extent_encryption(leaf, fi) ||
2225             btrfs_file_extent_other_encoding(leaf, fi))
2226                 return 0;
2227
2228         return 1;
2229 }
2230
2231 /*
2232  * Note the backref might has changed, and in this case we just return 0.
2233  */
2234 static noinline int relink_extent_backref(struct btrfs_path *path,
2235                                  struct sa_defrag_extent_backref *prev,
2236                                  struct sa_defrag_extent_backref *backref)
2237 {
2238         struct btrfs_file_extent_item *extent;
2239         struct btrfs_file_extent_item *item;
2240         struct btrfs_ordered_extent *ordered;
2241         struct btrfs_trans_handle *trans;
2242         struct btrfs_fs_info *fs_info;
2243         struct btrfs_root *root;
2244         struct btrfs_key key;
2245         struct extent_buffer *leaf;
2246         struct old_sa_defrag_extent *old = backref->old;
2247         struct new_sa_defrag_extent *new = old->new;
2248         struct inode *src_inode = new->inode;
2249         struct inode *inode;
2250         struct extent_state *cached = NULL;
2251         int ret = 0;
2252         u64 start;
2253         u64 len;
2254         u64 lock_start;
2255         u64 lock_end;
2256         bool merge = false;
2257         int index;
2258
2259         if (prev && prev->root_id == backref->root_id &&
2260             prev->inum == backref->inum &&
2261             prev->file_pos + prev->num_bytes == backref->file_pos)
2262                 merge = true;
2263
2264         /* step 1: get root */
2265         key.objectid = backref->root_id;
2266         key.type = BTRFS_ROOT_ITEM_KEY;
2267         key.offset = (u64)-1;
2268
2269         fs_info = BTRFS_I(src_inode)->root->fs_info;
2270         index = srcu_read_lock(&fs_info->subvol_srcu);
2271
2272         root = btrfs_read_fs_root_no_name(fs_info, &key);
2273         if (IS_ERR(root)) {
2274                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2275                 if (PTR_ERR(root) == -ENOENT)
2276                         return 0;
2277                 return PTR_ERR(root);
2278         }
2279
2280         if (btrfs_root_readonly(root)) {
2281                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2282                 return 0;
2283         }
2284
2285         /* step 2: get inode */
2286         key.objectid = backref->inum;
2287         key.type = BTRFS_INODE_ITEM_KEY;
2288         key.offset = 0;
2289
2290         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2291         if (IS_ERR(inode)) {
2292                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2293                 return 0;
2294         }
2295
2296         srcu_read_unlock(&fs_info->subvol_srcu, index);
2297
2298         /* step 3: relink backref */
2299         lock_start = backref->file_pos;
2300         lock_end = backref->file_pos + backref->num_bytes - 1;
2301         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2302                          0, &cached);
2303
2304         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2305         if (ordered) {
2306                 btrfs_put_ordered_extent(ordered);
2307                 goto out_unlock;
2308         }
2309
2310         trans = btrfs_join_transaction(root);
2311         if (IS_ERR(trans)) {
2312                 ret = PTR_ERR(trans);
2313                 goto out_unlock;
2314         }
2315
2316         key.objectid = backref->inum;
2317         key.type = BTRFS_EXTENT_DATA_KEY;
2318         key.offset = backref->file_pos;
2319
2320         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2321         if (ret < 0) {
2322                 goto out_free_path;
2323         } else if (ret > 0) {
2324                 ret = 0;
2325                 goto out_free_path;
2326         }
2327
2328         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2329                                 struct btrfs_file_extent_item);
2330
2331         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2332             backref->generation)
2333                 goto out_free_path;
2334
2335         btrfs_release_path(path);
2336
2337         start = backref->file_pos;
2338         if (backref->extent_offset < old->extent_offset + old->offset)
2339                 start += old->extent_offset + old->offset -
2340                          backref->extent_offset;
2341
2342         len = min(backref->extent_offset + backref->num_bytes,
2343                   old->extent_offset + old->offset + old->len);
2344         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2345
2346         ret = btrfs_drop_extents(trans, root, inode, start,
2347                                  start + len, 1);
2348         if (ret)
2349                 goto out_free_path;
2350 again:
2351         key.objectid = btrfs_ino(inode);
2352         key.type = BTRFS_EXTENT_DATA_KEY;
2353         key.offset = start;
2354
2355         path->leave_spinning = 1;
2356         if (merge) {
2357                 struct btrfs_file_extent_item *fi;
2358                 u64 extent_len;
2359                 struct btrfs_key found_key;
2360
2361                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2362                 if (ret < 0)
2363                         goto out_free_path;
2364
2365                 path->slots[0]--;
2366                 leaf = path->nodes[0];
2367                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2368
2369                 fi = btrfs_item_ptr(leaf, path->slots[0],
2370                                     struct btrfs_file_extent_item);
2371                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2372
2373                 if (extent_len + found_key.offset == start &&
2374                     relink_is_mergable(leaf, fi, new)) {
2375                         btrfs_set_file_extent_num_bytes(leaf, fi,
2376                                                         extent_len + len);
2377                         btrfs_mark_buffer_dirty(leaf);
2378                         inode_add_bytes(inode, len);
2379
2380                         ret = 1;
2381                         goto out_free_path;
2382                 } else {
2383                         merge = false;
2384                         btrfs_release_path(path);
2385                         goto again;
2386                 }
2387         }
2388
2389         ret = btrfs_insert_empty_item(trans, root, path, &key,
2390                                         sizeof(*extent));
2391         if (ret) {
2392                 btrfs_abort_transaction(trans, root, ret);
2393                 goto out_free_path;
2394         }
2395
2396         leaf = path->nodes[0];
2397         item = btrfs_item_ptr(leaf, path->slots[0],
2398                                 struct btrfs_file_extent_item);
2399         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2400         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2401         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2402         btrfs_set_file_extent_num_bytes(leaf, item, len);
2403         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2404         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2405         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2406         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2407         btrfs_set_file_extent_encryption(leaf, item, 0);
2408         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2409
2410         btrfs_mark_buffer_dirty(leaf);
2411         inode_add_bytes(inode, len);
2412         btrfs_release_path(path);
2413
2414         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2415                         new->disk_len, 0,
2416                         backref->root_id, backref->inum,
2417                         new->file_pos, 0);      /* start - extent_offset */
2418         if (ret) {
2419                 btrfs_abort_transaction(trans, root, ret);
2420                 goto out_free_path;
2421         }
2422
2423         ret = 1;
2424 out_free_path:
2425         btrfs_release_path(path);
2426         path->leave_spinning = 0;
2427         btrfs_end_transaction(trans, root);
2428 out_unlock:
2429         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2430                              &cached, GFP_NOFS);
2431         iput(inode);
2432         return ret;
2433 }
2434
2435 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2436 {
2437         struct old_sa_defrag_extent *old, *tmp;
2438
2439         if (!new)
2440                 return;
2441
2442         list_for_each_entry_safe(old, tmp, &new->head, list) {
2443                 list_del(&old->list);
2444                 kfree(old);
2445         }
2446         kfree(new);
2447 }
2448
2449 static void relink_file_extents(struct new_sa_defrag_extent *new)
2450 {
2451         struct btrfs_path *path;
2452         struct sa_defrag_extent_backref *backref;
2453         struct sa_defrag_extent_backref *prev = NULL;
2454         struct inode *inode;
2455         struct btrfs_root *root;
2456         struct rb_node *node;
2457         int ret;
2458
2459         inode = new->inode;
2460         root = BTRFS_I(inode)->root;
2461
2462         path = btrfs_alloc_path();
2463         if (!path)
2464                 return;
2465
2466         if (!record_extent_backrefs(path, new)) {
2467                 btrfs_free_path(path);
2468                 goto out;
2469         }
2470         btrfs_release_path(path);
2471
2472         while (1) {
2473                 node = rb_first(&new->root);
2474                 if (!node)
2475                         break;
2476                 rb_erase(node, &new->root);
2477
2478                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2479
2480                 ret = relink_extent_backref(path, prev, backref);
2481                 WARN_ON(ret < 0);
2482
2483                 kfree(prev);
2484
2485                 if (ret == 1)
2486                         prev = backref;
2487                 else
2488                         prev = NULL;
2489                 cond_resched();
2490         }
2491         kfree(prev);
2492
2493         btrfs_free_path(path);
2494 out:
2495         free_sa_defrag_extent(new);
2496
2497         atomic_dec(&root->fs_info->defrag_running);
2498         wake_up(&root->fs_info->transaction_wait);
2499 }
2500
2501 static struct new_sa_defrag_extent *
2502 record_old_file_extents(struct inode *inode,
2503                         struct btrfs_ordered_extent *ordered)
2504 {
2505         struct btrfs_root *root = BTRFS_I(inode)->root;
2506         struct btrfs_path *path;
2507         struct btrfs_key key;
2508         struct old_sa_defrag_extent *old;
2509         struct new_sa_defrag_extent *new;
2510         int ret;
2511
2512         new = kmalloc(sizeof(*new), GFP_NOFS);
2513         if (!new)
2514                 return NULL;
2515
2516         new->inode = inode;
2517         new->file_pos = ordered->file_offset;
2518         new->len = ordered->len;
2519         new->bytenr = ordered->start;
2520         new->disk_len = ordered->disk_len;
2521         new->compress_type = ordered->compress_type;
2522         new->root = RB_ROOT;
2523         INIT_LIST_HEAD(&new->head);
2524
2525         path = btrfs_alloc_path();
2526         if (!path)
2527                 goto out_kfree;
2528
2529         key.objectid = btrfs_ino(inode);
2530         key.type = BTRFS_EXTENT_DATA_KEY;
2531         key.offset = new->file_pos;
2532
2533         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2534         if (ret < 0)
2535                 goto out_free_path;
2536         if (ret > 0 && path->slots[0] > 0)
2537                 path->slots[0]--;
2538
2539         /* find out all the old extents for the file range */
2540         while (1) {
2541                 struct btrfs_file_extent_item *extent;
2542                 struct extent_buffer *l;
2543                 int slot;
2544                 u64 num_bytes;
2545                 u64 offset;
2546                 u64 end;
2547                 u64 disk_bytenr;
2548                 u64 extent_offset;
2549
2550                 l = path->nodes[0];
2551                 slot = path->slots[0];
2552
2553                 if (slot >= btrfs_header_nritems(l)) {
2554                         ret = btrfs_next_leaf(root, path);
2555                         if (ret < 0)
2556                                 goto out_free_path;
2557                         else if (ret > 0)
2558                                 break;
2559                         continue;
2560                 }
2561
2562                 btrfs_item_key_to_cpu(l, &key, slot);
2563
2564                 if (key.objectid != btrfs_ino(inode))
2565                         break;
2566                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2567                         break;
2568                 if (key.offset >= new->file_pos + new->len)
2569                         break;
2570
2571                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2572
2573                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2574                 if (key.offset + num_bytes < new->file_pos)
2575                         goto next;
2576
2577                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2578                 if (!disk_bytenr)
2579                         goto next;
2580
2581                 extent_offset = btrfs_file_extent_offset(l, extent);
2582
2583                 old = kmalloc(sizeof(*old), GFP_NOFS);
2584                 if (!old)
2585                         goto out_free_path;
2586
2587                 offset = max(new->file_pos, key.offset);
2588                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2589
2590                 old->bytenr = disk_bytenr;
2591                 old->extent_offset = extent_offset;
2592                 old->offset = offset - key.offset;
2593                 old->len = end - offset;
2594                 old->new = new;
2595                 old->count = 0;
2596                 list_add_tail(&old->list, &new->head);
2597 next:
2598                 path->slots[0]++;
2599                 cond_resched();
2600         }
2601
2602         btrfs_free_path(path);
2603         atomic_inc(&root->fs_info->defrag_running);
2604
2605         return new;
2606
2607 out_free_path:
2608         btrfs_free_path(path);
2609 out_kfree:
2610         free_sa_defrag_extent(new);
2611         return NULL;
2612 }
2613
2614 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2615                                          u64 start, u64 len)
2616 {
2617         struct btrfs_block_group_cache *cache;
2618
2619         cache = btrfs_lookup_block_group(root->fs_info, start);
2620         ASSERT(cache);
2621
2622         spin_lock(&cache->lock);
2623         cache->delalloc_bytes -= len;
2624         spin_unlock(&cache->lock);
2625
2626         btrfs_put_block_group(cache);
2627 }
2628
2629 /* as ordered data IO finishes, this gets called so we can finish
2630  * an ordered extent if the range of bytes in the file it covers are
2631  * fully written.
2632  */
2633 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2634 {
2635         struct inode *inode = ordered_extent->inode;
2636         struct btrfs_root *root = BTRFS_I(inode)->root;
2637         struct btrfs_trans_handle *trans = NULL;
2638         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2639         struct extent_state *cached_state = NULL;
2640         struct new_sa_defrag_extent *new = NULL;
2641         int compress_type = 0;
2642         int ret = 0;
2643         u64 logical_len = ordered_extent->len;
2644         bool nolock;
2645         bool truncated = false;
2646
2647         nolock = btrfs_is_free_space_inode(inode);
2648
2649         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2650                 ret = -EIO;
2651                 goto out;
2652         }
2653
2654         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2655                 truncated = true;
2656                 logical_len = ordered_extent->truncated_len;
2657                 /* Truncated the entire extent, don't bother adding */
2658                 if (!logical_len)
2659                         goto out;
2660         }
2661
2662         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2663                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2664                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2665                 if (nolock)
2666                         trans = btrfs_join_transaction_nolock(root);
2667                 else
2668                         trans = btrfs_join_transaction(root);
2669                 if (IS_ERR(trans)) {
2670                         ret = PTR_ERR(trans);
2671                         trans = NULL;
2672                         goto out;
2673                 }
2674                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2675                 ret = btrfs_update_inode_fallback(trans, root, inode);
2676                 if (ret) /* -ENOMEM or corruption */
2677                         btrfs_abort_transaction(trans, root, ret);
2678                 goto out;
2679         }
2680
2681         lock_extent_bits(io_tree, ordered_extent->file_offset,
2682                          ordered_extent->file_offset + ordered_extent->len - 1,
2683                          0, &cached_state);
2684
2685         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2686                         ordered_extent->file_offset + ordered_extent->len - 1,
2687                         EXTENT_DEFRAG, 1, cached_state);
2688         if (ret) {
2689                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2690                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2691                         /* the inode is shared */
2692                         new = record_old_file_extents(inode, ordered_extent);
2693
2694                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2695                         ordered_extent->file_offset + ordered_extent->len - 1,
2696                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2697         }
2698
2699         if (nolock)
2700                 trans = btrfs_join_transaction_nolock(root);
2701         else
2702                 trans = btrfs_join_transaction(root);
2703         if (IS_ERR(trans)) {
2704                 ret = PTR_ERR(trans);
2705                 trans = NULL;
2706                 goto out_unlock;
2707         }
2708
2709         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2710
2711         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2712                 compress_type = ordered_extent->compress_type;
2713         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2714                 BUG_ON(compress_type);
2715                 ret = btrfs_mark_extent_written(trans, inode,
2716                                                 ordered_extent->file_offset,
2717                                                 ordered_extent->file_offset +
2718                                                 logical_len);
2719         } else {
2720                 BUG_ON(root == root->fs_info->tree_root);
2721                 ret = insert_reserved_file_extent(trans, inode,
2722                                                 ordered_extent->file_offset,
2723                                                 ordered_extent->start,
2724                                                 ordered_extent->disk_len,
2725                                                 logical_len, logical_len,
2726                                                 compress_type, 0, 0,
2727                                                 BTRFS_FILE_EXTENT_REG);
2728                 if (!ret)
2729                         btrfs_release_delalloc_bytes(root,
2730                                                      ordered_extent->start,
2731                                                      ordered_extent->disk_len);
2732         }
2733         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2734                            ordered_extent->file_offset, ordered_extent->len,
2735                            trans->transid);
2736         if (ret < 0) {
2737                 btrfs_abort_transaction(trans, root, ret);
2738                 goto out_unlock;
2739         }
2740
2741         add_pending_csums(trans, inode, ordered_extent->file_offset,
2742                           &ordered_extent->list);
2743
2744         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2745         ret = btrfs_update_inode_fallback(trans, root, inode);
2746         if (ret) { /* -ENOMEM or corruption */
2747                 btrfs_abort_transaction(trans, root, ret);
2748                 goto out_unlock;
2749         }
2750         ret = 0;
2751 out_unlock:
2752         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2753                              ordered_extent->file_offset +
2754                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2755 out:
2756         if (root != root->fs_info->tree_root)
2757                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2758         if (trans)
2759                 btrfs_end_transaction(trans, root);
2760
2761         if (ret || truncated) {
2762                 u64 start, end;
2763
2764                 if (truncated)
2765                         start = ordered_extent->file_offset + logical_len;
2766                 else
2767                         start = ordered_extent->file_offset;
2768                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2769                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2770
2771                 /* Drop the cache for the part of the extent we didn't write. */
2772                 btrfs_drop_extent_cache(inode, start, end, 0);
2773
2774                 /*
2775                  * If the ordered extent had an IOERR or something else went
2776                  * wrong we need to return the space for this ordered extent
2777                  * back to the allocator.  We only free the extent in the
2778                  * truncated case if we didn't write out the extent at all.
2779                  */
2780                 if ((ret || !logical_len) &&
2781                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2782                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2783                         btrfs_free_reserved_extent(root, ordered_extent->start,
2784                                                    ordered_extent->disk_len, 1);
2785         }
2786
2787
2788         /*
2789          * This needs to be done to make sure anybody waiting knows we are done
2790          * updating everything for this ordered extent.
2791          */
2792         btrfs_remove_ordered_extent(inode, ordered_extent);
2793
2794         /* for snapshot-aware defrag */
2795         if (new) {
2796                 if (ret) {
2797                         free_sa_defrag_extent(new);
2798                         atomic_dec(&root->fs_info->defrag_running);
2799                 } else {
2800                         relink_file_extents(new);
2801                 }
2802         }
2803
2804         /* once for us */
2805         btrfs_put_ordered_extent(ordered_extent);
2806         /* once for the tree */
2807         btrfs_put_ordered_extent(ordered_extent);
2808
2809         return ret;
2810 }
2811
2812 static void finish_ordered_fn(struct btrfs_work *work)
2813 {
2814         struct btrfs_ordered_extent *ordered_extent;
2815         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2816         btrfs_finish_ordered_io(ordered_extent);
2817 }
2818
2819 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2820                                 struct extent_state *state, int uptodate)
2821 {
2822         struct inode *inode = page->mapping->host;
2823         struct btrfs_root *root = BTRFS_I(inode)->root;
2824         struct btrfs_ordered_extent *ordered_extent = NULL;
2825         struct btrfs_workqueue *workers;
2826
2827         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2828
2829         ClearPagePrivate2(page);
2830         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2831                                             end - start + 1, uptodate))
2832                 return 0;
2833
2834         btrfs_init_work(&ordered_extent->work, finish_ordered_fn, NULL, NULL);
2835
2836         if (btrfs_is_free_space_inode(inode))
2837                 workers = root->fs_info->endio_freespace_worker;
2838         else
2839                 workers = root->fs_info->endio_write_workers;
2840         btrfs_queue_work(workers, &ordered_extent->work);
2841
2842         return 0;
2843 }
2844
2845 /*
2846  * when reads are done, we need to check csums to verify the data is correct
2847  * if there's a match, we allow the bio to finish.  If not, the code in
2848  * extent_io.c will try to find good copies for us.
2849  */
2850 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2851                                       u64 phy_offset, struct page *page,
2852                                       u64 start, u64 end, int mirror)
2853 {
2854         size_t offset = start - page_offset(page);
2855         struct inode *inode = page->mapping->host;
2856         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2857         char *kaddr;
2858         struct btrfs_root *root = BTRFS_I(inode)->root;
2859         u32 csum_expected;
2860         u32 csum = ~(u32)0;
2861         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2862                                       DEFAULT_RATELIMIT_BURST);
2863
2864         if (PageChecked(page)) {
2865                 ClearPageChecked(page);
2866                 goto good;
2867         }
2868
2869         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2870                 goto good;
2871
2872         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2873             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2874                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2875                                   GFP_NOFS);
2876                 return 0;
2877         }
2878
2879         phy_offset >>= inode->i_sb->s_blocksize_bits;
2880         csum_expected = *(((u32 *)io_bio->csum) + phy_offset);
2881
2882         kaddr = kmap_atomic(page);
2883         csum = btrfs_csum_data(kaddr + offset, csum,  end - start + 1);
2884         btrfs_csum_final(csum, (char *)&csum);
2885         if (csum != csum_expected)
2886                 goto zeroit;
2887
2888         kunmap_atomic(kaddr);
2889 good:
2890         return 0;
2891
2892 zeroit:
2893         if (__ratelimit(&_rs))
2894                 btrfs_info(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
2895                         btrfs_ino(page->mapping->host), start, csum, csum_expected);
2896         memset(kaddr + offset, 1, end - start + 1);
2897         flush_dcache_page(page);
2898         kunmap_atomic(kaddr);
2899         if (csum_expected == 0)
2900                 return 0;
2901         return -EIO;
2902 }
2903
2904 struct delayed_iput {
2905         struct list_head list;
2906         struct inode *inode;
2907 };
2908
2909 /* JDM: If this is fs-wide, why can't we add a pointer to
2910  * btrfs_inode instead and avoid the allocation? */
2911 void btrfs_add_delayed_iput(struct inode *inode)
2912 {
2913         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2914         struct delayed_iput *delayed;
2915
2916         if (atomic_add_unless(&inode->i_count, -1, 1))
2917                 return;
2918
2919         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2920         delayed->inode = inode;
2921
2922         spin_lock(&fs_info->delayed_iput_lock);
2923         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2924         spin_unlock(&fs_info->delayed_iput_lock);
2925 }
2926
2927 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2928 {
2929         LIST_HEAD(list);
2930         struct btrfs_fs_info *fs_info = root->fs_info;
2931         struct delayed_iput *delayed;
2932         int empty;
2933
2934         spin_lock(&fs_info->delayed_iput_lock);
2935         empty = list_empty(&fs_info->delayed_iputs);
2936         spin_unlock(&fs_info->delayed_iput_lock);
2937         if (empty)
2938                 return;
2939
2940         spin_lock(&fs_info->delayed_iput_lock);
2941         list_splice_init(&fs_info->delayed_iputs, &list);
2942         spin_unlock(&fs_info->delayed_iput_lock);
2943
2944         while (!list_empty(&list)) {
2945                 delayed = list_entry(list.next, struct delayed_iput, list);
2946                 list_del(&delayed->list);
2947                 iput(delayed->inode);
2948                 kfree(delayed);
2949         }
2950 }
2951
2952 /*
2953  * This is called in transaction commit time. If there are no orphan
2954  * files in the subvolume, it removes orphan item and frees block_rsv
2955  * structure.
2956  */
2957 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2958                               struct btrfs_root *root)
2959 {
2960         struct btrfs_block_rsv *block_rsv;
2961         int ret;
2962
2963         if (atomic_read(&root->orphan_inodes) ||
2964             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2965                 return;
2966
2967         spin_lock(&root->orphan_lock);
2968         if (atomic_read(&root->orphan_inodes)) {
2969                 spin_unlock(&root->orphan_lock);
2970                 return;
2971         }
2972
2973         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
2974                 spin_unlock(&root->orphan_lock);
2975                 return;
2976         }
2977
2978         block_rsv = root->orphan_block_rsv;
2979         root->orphan_block_rsv = NULL;
2980         spin_unlock(&root->orphan_lock);
2981
2982         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
2983             btrfs_root_refs(&root->root_item) > 0) {
2984                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2985                                             root->root_key.objectid);
2986                 if (ret)
2987                         btrfs_abort_transaction(trans, root, ret);
2988                 else
2989                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
2990                                   &root->state);
2991         }
2992
2993         if (block_rsv) {
2994                 WARN_ON(block_rsv->size > 0);
2995                 btrfs_free_block_rsv(root, block_rsv);
2996         }
2997 }
2998
2999 /*
3000  * This creates an orphan entry for the given inode in case something goes
3001  * wrong in the middle of an unlink/truncate.
3002  *
3003  * NOTE: caller of this function should reserve 5 units of metadata for
3004  *       this function.
3005  */
3006 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3007 {
3008         struct btrfs_root *root = BTRFS_I(inode)->root;
3009         struct btrfs_block_rsv *block_rsv = NULL;
3010         int reserve = 0;
3011         int insert = 0;
3012         int ret;
3013
3014         if (!root->orphan_block_rsv) {
3015                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3016                 if (!block_rsv)
3017                         return -ENOMEM;
3018         }
3019
3020         spin_lock(&root->orphan_lock);
3021         if (!root->orphan_block_rsv) {
3022                 root->orphan_block_rsv = block_rsv;
3023         } else if (block_rsv) {
3024                 btrfs_free_block_rsv(root, block_rsv);
3025                 block_rsv = NULL;
3026         }
3027
3028         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3029                               &BTRFS_I(inode)->runtime_flags)) {
3030 #if 0
3031                 /*
3032                  * For proper ENOSPC handling, we should do orphan
3033                  * cleanup when mounting. But this introduces backward
3034                  * compatibility issue.
3035                  */
3036                 if (!xchg(&root->orphan_item_inserted, 1))
3037                         insert = 2;
3038                 else
3039                         insert = 1;
3040 #endif
3041                 insert = 1;
3042                 atomic_inc(&root->orphan_inodes);
3043         }
3044
3045         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3046                               &BTRFS_I(inode)->runtime_flags))
3047                 reserve = 1;
3048         spin_unlock(&root->orphan_lock);
3049
3050         /* grab metadata reservation from transaction handle */
3051         if (reserve) {
3052                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3053                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3054         }
3055
3056         /* insert an orphan item to track this unlinked/truncated file */
3057         if (insert >= 1) {
3058                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3059                 if (ret) {
3060                         atomic_dec(&root->orphan_inodes);
3061                         if (reserve) {
3062                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3063                                           &BTRFS_I(inode)->runtime_flags);
3064                                 btrfs_orphan_release_metadata(inode);
3065                         }
3066                         if (ret != -EEXIST) {
3067                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3068                                           &BTRFS_I(inode)->runtime_flags);
3069                                 btrfs_abort_transaction(trans, root, ret);
3070                                 return ret;
3071                         }
3072                 }
3073                 ret = 0;
3074         }
3075
3076         /* insert an orphan item to track subvolume contains orphan files */
3077         if (insert >= 2) {
3078                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3079                                                root->root_key.objectid);
3080                 if (ret && ret != -EEXIST) {
3081                         btrfs_abort_transaction(trans, root, ret);
3082                         return ret;
3083                 }
3084         }
3085         return 0;
3086 }
3087
3088 /*
3089  * We have done the truncate/delete so we can go ahead and remove the orphan
3090  * item for this particular inode.
3091  */
3092 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3093                             struct inode *inode)
3094 {
3095         struct btrfs_root *root = BTRFS_I(inode)->root;
3096         int delete_item = 0;
3097         int release_rsv = 0;
3098         int ret = 0;
3099
3100         spin_lock(&root->orphan_lock);
3101         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3102                                &BTRFS_I(inode)->runtime_flags))
3103                 delete_item = 1;
3104
3105         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3106                                &BTRFS_I(inode)->runtime_flags))
3107                 release_rsv = 1;
3108         spin_unlock(&root->orphan_lock);
3109
3110         if (delete_item) {
3111                 atomic_dec(&root->orphan_inodes);
3112                 if (trans)
3113                         ret = btrfs_del_orphan_item(trans, root,
3114                                                     btrfs_ino(inode));
3115         }
3116
3117         if (release_rsv)
3118                 btrfs_orphan_release_metadata(inode);
3119
3120         return ret;
3121 }
3122
3123 /*
3124  * this cleans up any orphans that may be left on the list from the last use
3125  * of this root.
3126  */
3127 int btrfs_orphan_cleanup(struct btrfs_root *root)
3128 {
3129         struct btrfs_path *path;
3130         struct extent_buffer *leaf;
3131         struct btrfs_key key, found_key;
3132         struct btrfs_trans_handle *trans;
3133         struct inode *inode;
3134         u64 last_objectid = 0;
3135         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3136
3137         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3138                 return 0;
3139
3140         path = btrfs_alloc_path();
3141         if (!path) {
3142                 ret = -ENOMEM;
3143                 goto out;
3144         }
3145         path->reada = -1;
3146
3147         key.objectid = BTRFS_ORPHAN_OBJECTID;
3148         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
3149         key.offset = (u64)-1;
3150
3151         while (1) {
3152                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3153                 if (ret < 0)
3154                         goto out;
3155
3156                 /*
3157                  * if ret == 0 means we found what we were searching for, which
3158                  * is weird, but possible, so only screw with path if we didn't
3159                  * find the key and see if we have stuff that matches
3160                  */
3161                 if (ret > 0) {
3162                         ret = 0;
3163                         if (path->slots[0] == 0)
3164                                 break;
3165                         path->slots[0]--;
3166                 }
3167
3168                 /* pull out the item */
3169                 leaf = path->nodes[0];
3170                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3171
3172                 /* make sure the item matches what we want */
3173                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3174                         break;
3175                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
3176                         break;
3177
3178                 /* release the path since we're done with it */
3179                 btrfs_release_path(path);
3180
3181                 /*
3182                  * this is where we are basically btrfs_lookup, without the
3183                  * crossing root thing.  we store the inode number in the
3184                  * offset of the orphan item.
3185                  */
3186
3187                 if (found_key.offset == last_objectid) {
3188                         btrfs_err(root->fs_info,
3189                                 "Error removing orphan entry, stopping orphan cleanup");
3190                         ret = -EINVAL;
3191                         goto out;
3192                 }
3193
3194                 last_objectid = found_key.offset;
3195
3196                 found_key.objectid = found_key.offset;
3197                 found_key.type = BTRFS_INODE_ITEM_KEY;
3198                 found_key.offset = 0;
3199                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3200                 ret = PTR_ERR_OR_ZERO(inode);
3201                 if (ret && ret != -ESTALE)
3202                         goto out;
3203
3204                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3205                         struct btrfs_root *dead_root;
3206                         struct btrfs_fs_info *fs_info = root->fs_info;
3207                         int is_dead_root = 0;
3208
3209                         /*
3210                          * this is an orphan in the tree root. Currently these
3211                          * could come from 2 sources:
3212                          *  a) a snapshot deletion in progress
3213                          *  b) a free space cache inode
3214                          * We need to distinguish those two, as the snapshot
3215                          * orphan must not get deleted.
3216                          * find_dead_roots already ran before us, so if this
3217                          * is a snapshot deletion, we should find the root
3218                          * in the dead_roots list
3219                          */
3220                         spin_lock(&fs_info->trans_lock);
3221                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3222                                             root_list) {
3223                                 if (dead_root->root_key.objectid ==
3224                                     found_key.objectid) {
3225                                         is_dead_root = 1;
3226                                         break;
3227                                 }
3228                         }
3229                         spin_unlock(&fs_info->trans_lock);
3230                         if (is_dead_root) {
3231                                 /* prevent this orphan from being found again */
3232                                 key.offset = found_key.objectid - 1;
3233                                 continue;
3234                         }
3235                 }
3236                 /*
3237                  * Inode is already gone but the orphan item is still there,
3238                  * kill the orphan item.
3239                  */
3240                 if (ret == -ESTALE) {
3241                         trans = btrfs_start_transaction(root, 1);
3242                         if (IS_ERR(trans)) {
3243                                 ret = PTR_ERR(trans);
3244                                 goto out;
3245                         }
3246                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3247                                 found_key.objectid);
3248                         ret = btrfs_del_orphan_item(trans, root,
3249                                                     found_key.objectid);
3250                         btrfs_end_transaction(trans, root);
3251                         if (ret)
3252                                 goto out;
3253                         continue;
3254                 }
3255
3256                 /*
3257                  * add this inode to the orphan list so btrfs_orphan_del does
3258                  * the proper thing when we hit it
3259                  */
3260                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3261                         &BTRFS_I(inode)->runtime_flags);
3262                 atomic_inc(&root->orphan_inodes);
3263
3264                 /* if we have links, this was a truncate, lets do that */
3265                 if (inode->i_nlink) {
3266                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3267                                 iput(inode);
3268                                 continue;
3269                         }
3270                         nr_truncate++;
3271
3272                         /* 1 for the orphan item deletion. */
3273                         trans = btrfs_start_transaction(root, 1);
3274                         if (IS_ERR(trans)) {
3275                                 iput(inode);
3276                                 ret = PTR_ERR(trans);
3277                                 goto out;
3278                         }
3279                         ret = btrfs_orphan_add(trans, inode);
3280                         btrfs_end_transaction(trans, root);
3281                         if (ret) {
3282                                 iput(inode);
3283                                 goto out;
3284                         }
3285
3286                         ret = btrfs_truncate(inode);
3287                         if (ret)
3288                                 btrfs_orphan_del(NULL, inode);
3289                 } else {
3290                         nr_unlink++;
3291                 }
3292
3293                 /* this will do delete_inode and everything for us */
3294                 iput(inode);
3295                 if (ret)
3296                         goto out;
3297         }
3298         /* release the path since we're done with it */
3299         btrfs_release_path(path);
3300
3301         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3302
3303         if (root->orphan_block_rsv)
3304                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3305                                         (u64)-1);
3306
3307         if (root->orphan_block_rsv ||
3308             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3309                 trans = btrfs_join_transaction(root);
3310                 if (!IS_ERR(trans))
3311                         btrfs_end_transaction(trans, root);
3312         }
3313
3314         if (nr_unlink)
3315                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3316         if (nr_truncate)
3317                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3318
3319 out:
3320         if (ret)
3321                 btrfs_crit(root->fs_info,
3322                         "could not do orphan cleanup %d", ret);
3323         btrfs_free_path(path);
3324         return ret;
3325 }
3326
3327 /*
3328  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3329  * don't find any xattrs, we know there can't be any acls.
3330  *
3331  * slot is the slot the inode is in, objectid is the objectid of the inode
3332  */
3333 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3334                                           int slot, u64 objectid,
3335                                           int *first_xattr_slot)
3336 {
3337         u32 nritems = btrfs_header_nritems(leaf);
3338         struct btrfs_key found_key;
3339         static u64 xattr_access = 0;
3340         static u64 xattr_default = 0;
3341         int scanned = 0;
3342
3343         if (!xattr_access) {
3344                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3345                                         strlen(POSIX_ACL_XATTR_ACCESS));
3346                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3347                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3348         }
3349
3350         slot++;
3351         *first_xattr_slot = -1;
3352         while (slot < nritems) {
3353                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3354
3355                 /* we found a different objectid, there must not be acls */
3356                 if (found_key.objectid != objectid)
3357                         return 0;
3358
3359                 /* we found an xattr, assume we've got an acl */
3360                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3361                         if (*first_xattr_slot == -1)
3362                                 *first_xattr_slot = slot;
3363                         if (found_key.offset == xattr_access ||
3364                             found_key.offset == xattr_default)
3365                                 return 1;
3366                 }
3367
3368                 /*
3369                  * we found a key greater than an xattr key, there can't
3370                  * be any acls later on
3371                  */
3372                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3373                         return 0;
3374
3375                 slot++;
3376                 scanned++;
3377
3378                 /*
3379                  * it goes inode, inode backrefs, xattrs, extents,
3380                  * so if there are a ton of hard links to an inode there can
3381                  * be a lot of backrefs.  Don't waste time searching too hard,
3382                  * this is just an optimization
3383                  */
3384                 if (scanned >= 8)
3385                         break;
3386         }
3387         /* we hit the end of the leaf before we found an xattr or
3388          * something larger than an xattr.  We have to assume the inode
3389          * has acls
3390          */
3391         if (*first_xattr_slot == -1)
3392                 *first_xattr_slot = slot;
3393         return 1;
3394 }
3395
3396 /*
3397  * read an inode from the btree into the in-memory inode
3398  */
3399 static void btrfs_read_locked_inode(struct inode *inode)
3400 {
3401         struct btrfs_path *path;
3402         struct extent_buffer *leaf;
3403         struct btrfs_inode_item *inode_item;
3404         struct btrfs_timespec *tspec;
3405         struct btrfs_root *root = BTRFS_I(inode)->root;
3406         struct btrfs_key location;
3407         unsigned long ptr;
3408         int maybe_acls;
3409         u32 rdev;
3410         int ret;
3411         bool filled = false;
3412         int first_xattr_slot;
3413
3414         ret = btrfs_fill_inode(inode, &rdev);
3415         if (!ret)
3416                 filled = true;
3417
3418         path = btrfs_alloc_path();
3419         if (!path)
3420                 goto make_bad;
3421
3422         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3423
3424         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3425         if (ret)
3426                 goto make_bad;
3427
3428         leaf = path->nodes[0];
3429
3430         if (filled)
3431                 goto cache_index;
3432
3433         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3434                                     struct btrfs_inode_item);
3435         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3436         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3437         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3438         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3439         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3440
3441         tspec = btrfs_inode_atime(inode_item);
3442         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3443         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3444
3445         tspec = btrfs_inode_mtime(inode_item);
3446         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3447         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3448
3449         tspec = btrfs_inode_ctime(inode_item);
3450         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3451         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3452
3453         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3454         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3455         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3456
3457         /*
3458          * If we were modified in the current generation and evicted from memory
3459          * and then re-read we need to do a full sync since we don't have any
3460          * idea about which extents were modified before we were evicted from
3461          * cache.
3462          */
3463         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3464                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3465                         &BTRFS_I(inode)->runtime_flags);
3466
3467         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3468         inode->i_generation = BTRFS_I(inode)->generation;
3469         inode->i_rdev = 0;
3470         rdev = btrfs_inode_rdev(leaf, inode_item);
3471
3472         BTRFS_I(inode)->index_cnt = (u64)-1;
3473         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3474
3475 cache_index:
3476         path->slots[0]++;
3477         if (inode->i_nlink != 1 ||
3478             path->slots[0] >= btrfs_header_nritems(leaf))
3479                 goto cache_acl;
3480
3481         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3482         if (location.objectid != btrfs_ino(inode))
3483                 goto cache_acl;
3484
3485         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3486         if (location.type == BTRFS_INODE_REF_KEY) {
3487                 struct btrfs_inode_ref *ref;
3488
3489                 ref = (struct btrfs_inode_ref *)ptr;
3490                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3491         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3492                 struct btrfs_inode_extref *extref;
3493
3494                 extref = (struct btrfs_inode_extref *)ptr;
3495                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3496                                                                      extref);
3497         }
3498 cache_acl:
3499         /*
3500          * try to precache a NULL acl entry for files that don't have
3501          * any xattrs or acls
3502          */
3503         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3504                                            btrfs_ino(inode), &first_xattr_slot);
3505         if (first_xattr_slot != -1) {
3506                 path->slots[0] = first_xattr_slot;
3507                 ret = btrfs_load_inode_props(inode, path);
3508                 if (ret)
3509                         btrfs_err(root->fs_info,
3510                                   "error loading props for ino %llu (root %llu): %d",
3511                                   btrfs_ino(inode),
3512                                   root->root_key.objectid, ret);
3513         }
3514         btrfs_free_path(path);
3515
3516         if (!maybe_acls)
3517                 cache_no_acl(inode);
3518
3519         switch (inode->i_mode & S_IFMT) {
3520         case S_IFREG:
3521                 inode->i_mapping->a_ops = &btrfs_aops;
3522                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3523                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3524                 inode->i_fop = &btrfs_file_operations;
3525                 inode->i_op = &btrfs_file_inode_operations;
3526                 break;
3527         case S_IFDIR:
3528                 inode->i_fop = &btrfs_dir_file_operations;
3529                 if (root == root->fs_info->tree_root)
3530                         inode->i_op = &btrfs_dir_ro_inode_operations;
3531                 else
3532                         inode->i_op = &btrfs_dir_inode_operations;
3533                 break;
3534         case S_IFLNK:
3535                 inode->i_op = &btrfs_symlink_inode_operations;
3536                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3537                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3538                 break;
3539         default:
3540                 inode->i_op = &btrfs_special_inode_operations;
3541                 init_special_inode(inode, inode->i_mode, rdev);
3542                 break;
3543         }
3544
3545         btrfs_update_iflags(inode);
3546         return;
3547
3548 make_bad:
3549         btrfs_free_path(path);
3550         make_bad_inode(inode);
3551 }
3552
3553 /*
3554  * given a leaf and an inode, copy the inode fields into the leaf
3555  */
3556 static void fill_inode_item(struct btrfs_trans_handle *trans,
3557                             struct extent_buffer *leaf,
3558                             struct btrfs_inode_item *item,
3559                             struct inode *inode)
3560 {
3561         struct btrfs_map_token token;
3562
3563         btrfs_init_map_token(&token);
3564
3565         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3566         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3567         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3568                                    &token);
3569         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3570         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3571
3572         btrfs_set_token_timespec_sec(leaf, btrfs_inode_atime(item),
3573                                      inode->i_atime.tv_sec, &token);
3574         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_atime(item),
3575                                       inode->i_atime.tv_nsec, &token);
3576
3577         btrfs_set_token_timespec_sec(leaf, btrfs_inode_mtime(item),
3578                                      inode->i_mtime.tv_sec, &token);
3579         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_mtime(item),
3580                                       inode->i_mtime.tv_nsec, &token);
3581
3582         btrfs_set_token_timespec_sec(leaf, btrfs_inode_ctime(item),
3583                                      inode->i_ctime.tv_sec, &token);
3584         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_ctime(item),
3585                                       inode->i_ctime.tv_nsec, &token);
3586
3587         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3588                                      &token);
3589         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3590                                          &token);
3591         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3592         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3593         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3594         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3595         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3596 }
3597
3598 /*
3599  * copy everything in the in-memory inode into the btree.
3600  */
3601 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3602                                 struct btrfs_root *root, struct inode *inode)
3603 {
3604         struct btrfs_inode_item *inode_item;
3605         struct btrfs_path *path;
3606         struct extent_buffer *leaf;
3607         int ret;
3608
3609         path = btrfs_alloc_path();
3610         if (!path)
3611                 return -ENOMEM;
3612
3613         path->leave_spinning = 1;
3614         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3615                                  1);
3616         if (ret) {
3617                 if (ret > 0)
3618                         ret = -ENOENT;
3619                 goto failed;
3620         }
3621
3622         leaf = path->nodes[0];
3623         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3624                                     struct btrfs_inode_item);
3625
3626         fill_inode_item(trans, leaf, inode_item, inode);
3627         btrfs_mark_buffer_dirty(leaf);
3628         btrfs_set_inode_last_trans(trans, inode);
3629         ret = 0;
3630 failed:
3631         btrfs_free_path(path);
3632         return ret;
3633 }
3634
3635 /*
3636  * copy everything in the in-memory inode into the btree.
3637  */
3638 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3639                                 struct btrfs_root *root, struct inode *inode)
3640 {
3641         int ret;
3642
3643         /*
3644          * If the inode is a free space inode, we can deadlock during commit
3645          * if we put it into the delayed code.
3646          *
3647          * The data relocation inode should also be directly updated
3648          * without delay
3649          */
3650         if (!btrfs_is_free_space_inode(inode)
3651             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
3652                 btrfs_update_root_times(trans, root);
3653
3654                 ret = btrfs_delayed_update_inode(trans, root, inode);
3655                 if (!ret)
3656                         btrfs_set_inode_last_trans(trans, inode);
3657                 return ret;
3658         }
3659
3660         return btrfs_update_inode_item(trans, root, inode);
3661 }
3662
3663 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3664                                          struct btrfs_root *root,
3665                                          struct inode *inode)
3666 {
3667         int ret;
3668
3669         ret = btrfs_update_inode(trans, root, inode);
3670         if (ret == -ENOSPC)
3671                 return btrfs_update_inode_item(trans, root, inode);
3672         return ret;
3673 }
3674
3675 /*
3676  * unlink helper that gets used here in inode.c and in the tree logging
3677  * recovery code.  It remove a link in a directory with a given name, and
3678  * also drops the back refs in the inode to the directory
3679  */
3680 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3681                                 struct btrfs_root *root,
3682                                 struct inode *dir, struct inode *inode,
3683                                 const char *name, int name_len)
3684 {
3685         struct btrfs_path *path;
3686         int ret = 0;
3687         struct extent_buffer *leaf;
3688         struct btrfs_dir_item *di;
3689         struct btrfs_key key;
3690         u64 index;
3691         u64 ino = btrfs_ino(inode);
3692         u64 dir_ino = btrfs_ino(dir);
3693
3694         path = btrfs_alloc_path();
3695         if (!path) {
3696                 ret = -ENOMEM;
3697                 goto out;
3698         }
3699
3700         path->leave_spinning = 1;
3701         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3702                                     name, name_len, -1);
3703         if (IS_ERR(di)) {
3704                 ret = PTR_ERR(di);
3705                 goto err;
3706         }
3707         if (!di) {
3708                 ret = -ENOENT;
3709                 goto err;
3710         }
3711         leaf = path->nodes[0];
3712         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3713         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3714         if (ret)
3715                 goto err;
3716         btrfs_release_path(path);
3717
3718         /*
3719          * If we don't have dir index, we have to get it by looking up
3720          * the inode ref, since we get the inode ref, remove it directly,
3721          * it is unnecessary to do delayed deletion.
3722          *
3723          * But if we have dir index, needn't search inode ref to get it.
3724          * Since the inode ref is close to the inode item, it is better
3725          * that we delay to delete it, and just do this deletion when
3726          * we update the inode item.
3727          */
3728         if (BTRFS_I(inode)->dir_index) {
3729                 ret = btrfs_delayed_delete_inode_ref(inode);
3730                 if (!ret) {
3731                         index = BTRFS_I(inode)->dir_index;
3732                         goto skip_backref;
3733                 }
3734         }
3735
3736         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3737                                   dir_ino, &index);
3738         if (ret) {
3739                 btrfs_info(root->fs_info,
3740                         "failed to delete reference to %.*s, inode %llu parent %llu",
3741                         name_len, name, ino, dir_ino);
3742                 btrfs_abort_transaction(trans, root, ret);
3743                 goto err;
3744         }
3745 skip_backref:
3746         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3747         if (ret) {
3748                 btrfs_abort_transaction(trans, root, ret);
3749                 goto err;
3750         }
3751
3752         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3753                                          inode, dir_ino);
3754         if (ret != 0 && ret != -ENOENT) {
3755                 btrfs_abort_transaction(trans, root, ret);
3756                 goto err;
3757         }
3758
3759         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3760                                            dir, index);
3761         if (ret == -ENOENT)
3762                 ret = 0;
3763         else if (ret)
3764                 btrfs_abort_transaction(trans, root, ret);
3765 err:
3766         btrfs_free_path(path);
3767         if (ret)
3768                 goto out;
3769
3770         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3771         inode_inc_iversion(inode);
3772         inode_inc_iversion(dir);
3773         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3774         ret = btrfs_update_inode(trans, root, dir);
3775 out:
3776         return ret;
3777 }
3778
3779 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3780                        struct btrfs_root *root,
3781                        struct inode *dir, struct inode *inode,
3782                        const char *name, int name_len)
3783 {
3784         int ret;
3785         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3786         if (!ret) {
3787                 drop_nlink(inode);
3788                 ret = btrfs_update_inode(trans, root, inode);
3789         }
3790         return ret;
3791 }
3792
3793 /*
3794  * helper to start transaction for unlink and rmdir.
3795  *
3796  * unlink and rmdir are special in btrfs, they do not always free space, so
3797  * if we cannot make our reservations the normal way try and see if there is
3798  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3799  * allow the unlink to occur.
3800  */
3801 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3802 {
3803         struct btrfs_trans_handle *trans;
3804         struct btrfs_root *root = BTRFS_I(dir)->root;
3805         int ret;
3806
3807         /*
3808          * 1 for the possible orphan item
3809          * 1 for the dir item
3810          * 1 for the dir index
3811          * 1 for the inode ref
3812          * 1 for the inode
3813          */
3814         trans = btrfs_start_transaction(root, 5);
3815         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3816                 return trans;
3817
3818         if (PTR_ERR(trans) == -ENOSPC) {
3819                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3820
3821                 trans = btrfs_start_transaction(root, 0);
3822                 if (IS_ERR(trans))
3823                         return trans;
3824                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3825                                                &root->fs_info->trans_block_rsv,
3826                                                num_bytes, 5);
3827                 if (ret) {
3828                         btrfs_end_transaction(trans, root);
3829                         return ERR_PTR(ret);
3830                 }
3831                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3832                 trans->bytes_reserved = num_bytes;
3833         }
3834         return trans;
3835 }
3836
3837 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3838 {
3839         struct btrfs_root *root = BTRFS_I(dir)->root;
3840         struct btrfs_trans_handle *trans;
3841         struct inode *inode = dentry->d_inode;
3842         int ret;
3843
3844         trans = __unlink_start_trans(dir);
3845         if (IS_ERR(trans))
3846                 return PTR_ERR(trans);
3847
3848         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3849
3850         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3851                                  dentry->d_name.name, dentry->d_name.len);
3852         if (ret)
3853                 goto out;
3854
3855         if (inode->i_nlink == 0) {
3856                 ret = btrfs_orphan_add(trans, inode);
3857                 if (ret)
3858                         goto out;
3859         }
3860
3861 out:
3862         btrfs_end_transaction(trans, root);
3863         btrfs_btree_balance_dirty(root);
3864         return ret;
3865 }
3866
3867 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3868                         struct btrfs_root *root,
3869                         struct inode *dir, u64 objectid,
3870                         const char *name, int name_len)
3871 {
3872         struct btrfs_path *path;
3873         struct extent_buffer *leaf;
3874         struct btrfs_dir_item *di;
3875         struct btrfs_key key;
3876         u64 index;
3877         int ret;
3878         u64 dir_ino = btrfs_ino(dir);
3879
3880         path = btrfs_alloc_path();
3881         if (!path)
3882                 return -ENOMEM;
3883
3884         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3885                                    name, name_len, -1);
3886         if (IS_ERR_OR_NULL(di)) {
3887                 if (!di)
3888                         ret = -ENOENT;
3889                 else
3890                         ret = PTR_ERR(di);
3891                 goto out;
3892         }
3893
3894         leaf = path->nodes[0];
3895         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3896         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3897         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3898         if (ret) {
3899                 btrfs_abort_transaction(trans, root, ret);
3900                 goto out;
3901         }
3902         btrfs_release_path(path);
3903
3904         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3905                                  objectid, root->root_key.objectid,
3906                                  dir_ino, &index, name, name_len);
3907         if (ret < 0) {
3908                 if (ret != -ENOENT) {
3909                         btrfs_abort_transaction(trans, root, ret);
3910                         goto out;
3911                 }
3912                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3913                                                  name, name_len);
3914                 if (IS_ERR_OR_NULL(di)) {
3915                         if (!di)
3916                                 ret = -ENOENT;
3917                         else
3918                                 ret = PTR_ERR(di);
3919                         btrfs_abort_transaction(trans, root, ret);
3920                         goto out;
3921                 }
3922
3923                 leaf = path->nodes[0];
3924                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3925                 btrfs_release_path(path);
3926                 index = key.offset;
3927         }
3928         btrfs_release_path(path);
3929
3930         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3931         if (ret) {
3932                 btrfs_abort_transaction(trans, root, ret);
3933                 goto out;
3934         }
3935
3936         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3937         inode_inc_iversion(dir);
3938         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3939         ret = btrfs_update_inode_fallback(trans, root, dir);
3940         if (ret)
3941                 btrfs_abort_transaction(trans, root, ret);
3942 out:
3943         btrfs_free_path(path);
3944         return ret;
3945 }
3946
3947 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3948 {
3949         struct inode *inode = dentry->d_inode;
3950         int err = 0;
3951         struct btrfs_root *root = BTRFS_I(dir)->root;
3952         struct btrfs_trans_handle *trans;
3953
3954         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
3955                 return -ENOTEMPTY;
3956         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3957                 return -EPERM;
3958
3959         trans = __unlink_start_trans(dir);
3960         if (IS_ERR(trans))
3961                 return PTR_ERR(trans);
3962
3963         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3964                 err = btrfs_unlink_subvol(trans, root, dir,
3965                                           BTRFS_I(inode)->location.objectid,
3966                                           dentry->d_name.name,
3967                                           dentry->d_name.len);
3968                 goto out;
3969         }
3970
3971         err = btrfs_orphan_add(trans, inode);
3972         if (err)
3973                 goto out;
3974
3975         /* now the directory is empty */
3976         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3977                                  dentry->d_name.name, dentry->d_name.len);
3978         if (!err)
3979                 btrfs_i_size_write(inode, 0);
3980 out:
3981         btrfs_end_transaction(trans, root);
3982         btrfs_btree_balance_dirty(root);
3983
3984         return err;
3985 }
3986
3987 /*
3988  * this can truncate away extent items, csum items and directory items.
3989  * It starts at a high offset and removes keys until it can't find
3990  * any higher than new_size
3991  *
3992  * csum items that cross the new i_size are truncated to the new size
3993  * as well.
3994  *
3995  * min_type is the minimum key type to truncate down to.  If set to 0, this
3996  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3997  */
3998 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3999                                struct btrfs_root *root,
4000                                struct inode *inode,
4001                                u64 new_size, u32 min_type)
4002 {
4003         struct btrfs_path *path;
4004         struct extent_buffer *leaf;
4005         struct btrfs_file_extent_item *fi;
4006         struct btrfs_key key;
4007         struct btrfs_key found_key;
4008         u64 extent_start = 0;
4009         u64 extent_num_bytes = 0;
4010         u64 extent_offset = 0;
4011         u64 item_end = 0;
4012         u64 last_size = (u64)-1;
4013         u32 found_type = (u8)-1;
4014         int found_extent;
4015         int del_item;
4016         int pending_del_nr = 0;
4017         int pending_del_slot = 0;
4018         int extent_type = -1;
4019         int ret;
4020         int err = 0;
4021         u64 ino = btrfs_ino(inode);
4022
4023         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4024
4025         path = btrfs_alloc_path();
4026         if (!path)
4027                 return -ENOMEM;
4028         path->reada = -1;
4029
4030         /*
4031          * We want to drop from the next block forward in case this new size is
4032          * not block aligned since we will be keeping the last block of the
4033          * extent just the way it is.
4034          */
4035         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4036             root == root->fs_info->tree_root)
4037                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4038                                         root->sectorsize), (u64)-1, 0);
4039
4040         /*
4041          * This function is also used to drop the items in the log tree before
4042          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4043          * it is used to drop the loged items. So we shouldn't kill the delayed
4044          * items.
4045          */
4046         if (min_type == 0 && root == BTRFS_I(inode)->root)
4047                 btrfs_kill_delayed_inode_items(inode);
4048
4049         key.objectid = ino;
4050         key.offset = (u64)-1;
4051         key.type = (u8)-1;
4052
4053 search_again:
4054         path->leave_spinning = 1;
4055         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4056         if (ret < 0) {
4057                 err = ret;
4058                 goto out;
4059         }
4060
4061         if (ret > 0) {
4062                 /* there are no items in the tree for us to truncate, we're
4063                  * done
4064                  */
4065                 if (path->slots[0] == 0)
4066                         goto out;
4067                 path->slots[0]--;
4068         }
4069
4070         while (1) {
4071                 fi = NULL;
4072                 leaf = path->nodes[0];
4073                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4074                 found_type = btrfs_key_type(&found_key);
4075
4076                 if (found_key.objectid != ino)
4077                         break;
4078
4079                 if (found_type < min_type)
4080                         break;
4081
4082                 item_end = found_key.offset;
4083                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4084                         fi = btrfs_item_ptr(leaf, path->slots[0],
4085                                             struct btrfs_file_extent_item);
4086                         extent_type = btrfs_file_extent_type(leaf, fi);
4087                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4088                                 item_end +=
4089                                     btrfs_file_extent_num_bytes(leaf, fi);
4090                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4091                                 item_end += btrfs_file_extent_inline_len(leaf,
4092                                                          path->slots[0], fi);
4093                         }
4094                         item_end--;
4095                 }
4096                 if (found_type > min_type) {
4097                         del_item = 1;
4098                 } else {
4099                         if (item_end < new_size)
4100                                 break;
4101                         if (found_key.offset >= new_size)
4102                                 del_item = 1;
4103                         else
4104                                 del_item = 0;
4105                 }
4106                 found_extent = 0;
4107                 /* FIXME, shrink the extent if the ref count is only 1 */
4108                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4109                         goto delete;
4110
4111                 if (del_item)
4112                         last_size = found_key.offset;
4113                 else
4114                         last_size = new_size;
4115
4116                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4117                         u64 num_dec;
4118                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4119                         if (!del_item) {
4120                                 u64 orig_num_bytes =
4121                                         btrfs_file_extent_num_bytes(leaf, fi);
4122                                 extent_num_bytes = ALIGN(new_size -
4123                                                 found_key.offset,
4124                                                 root->sectorsize);
4125                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4126                                                          extent_num_bytes);
4127                                 num_dec = (orig_num_bytes -
4128                                            extent_num_bytes);
4129                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4130                                              &root->state) &&
4131                                     extent_start != 0)
4132                                         inode_sub_bytes(inode, num_dec);
4133                                 btrfs_mark_buffer_dirty(leaf);
4134                         } else {
4135                                 extent_num_bytes =
4136                                         btrfs_file_extent_disk_num_bytes(leaf,
4137                                                                          fi);
4138                                 extent_offset = found_key.offset -
4139                                         btrfs_file_extent_offset(leaf, fi);
4140
4141                                 /* FIXME blocksize != 4096 */
4142                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4143                                 if (extent_start != 0) {
4144                                         found_extent = 1;
4145                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4146                                                      &root->state))
4147                                                 inode_sub_bytes(inode, num_dec);
4148                                 }
4149                         }
4150                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4151                         /*
4152                          * we can't truncate inline items that have had
4153                          * special encodings
4154                          */
4155                         if (!del_item &&
4156                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4157                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4158                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4159                                 u32 size = new_size - found_key.offset;
4160
4161                                 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4162                                         inode_sub_bytes(inode, item_end + 1 -
4163                                                         new_size);
4164
4165                                 /*
4166                                  * update the ram bytes to properly reflect
4167                                  * the new size of our item
4168                                  */
4169                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4170                                 size =
4171                                     btrfs_file_extent_calc_inline_size(size);
4172                                 btrfs_truncate_item(root, path, size, 1);
4173                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4174                                             &root->state)) {
4175                                 inode_sub_bytes(inode, item_end + 1 -
4176                                                 found_key.offset);
4177                         }
4178                 }
4179 delete:
4180                 if (del_item) {
4181                         if (!pending_del_nr) {
4182                                 /* no pending yet, add ourselves */
4183                                 pending_del_slot = path->slots[0];
4184                                 pending_del_nr = 1;
4185                         } else if (pending_del_nr &&
4186                                    path->slots[0] + 1 == pending_del_slot) {
4187                                 /* hop on the pending chunk */
4188                                 pending_del_nr++;
4189                                 pending_del_slot = path->slots[0];
4190                         } else {
4191                                 BUG();
4192                         }
4193                 } else {
4194                         break;
4195                 }
4196                 if (found_extent &&
4197                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4198                      root == root->fs_info->tree_root)) {
4199                         btrfs_set_path_blocking(path);
4200                         ret = btrfs_free_extent(trans, root, extent_start,
4201                                                 extent_num_bytes, 0,
4202                                                 btrfs_header_owner(leaf),
4203                                                 ino, extent_offset, 0);
4204                         BUG_ON(ret);
4205                 }
4206
4207                 if (found_type == BTRFS_INODE_ITEM_KEY)
4208                         break;
4209
4210                 if (path->slots[0] == 0 ||
4211                     path->slots[0] != pending_del_slot) {
4212                         if (pending_del_nr) {
4213                                 ret = btrfs_del_items(trans, root, path,
4214                                                 pending_del_slot,
4215                                                 pending_del_nr);
4216                                 if (ret) {
4217                                         btrfs_abort_transaction(trans,
4218                                                                 root, ret);
4219                                         goto error;
4220                                 }
4221                                 pending_del_nr = 0;
4222                         }
4223                         btrfs_release_path(path);
4224                         goto search_again;
4225                 } else {
4226                         path->slots[0]--;
4227                 }
4228         }
4229 out:
4230         if (pending_del_nr) {
4231                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4232                                       pending_del_nr);
4233                 if (ret)
4234                         btrfs_abort_transaction(trans, root, ret);
4235         }
4236 error:
4237         if (last_size != (u64)-1)
4238                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4239         btrfs_free_path(path);
4240         return err;
4241 }
4242
4243 /*
4244  * btrfs_truncate_page - read, zero a chunk and write a page
4245  * @inode - inode that we're zeroing
4246  * @from - the offset to start zeroing
4247  * @len - the length to zero, 0 to zero the entire range respective to the
4248  *      offset
4249  * @front - zero up to the offset instead of from the offset on
4250  *
4251  * This will find the page for the "from" offset and cow the page and zero the
4252  * part we want to zero.  This is used with truncate and hole punching.
4253  */
4254 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4255                         int front)
4256 {
4257         struct address_space *mapping = inode->i_mapping;
4258         struct btrfs_root *root = BTRFS_I(inode)->root;
4259         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4260         struct btrfs_ordered_extent *ordered;
4261         struct extent_state *cached_state = NULL;
4262         char *kaddr;
4263         u32 blocksize = root->sectorsize;
4264         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4265         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4266         struct page *page;
4267         gfp_t mask = btrfs_alloc_write_mask(mapping);
4268         int ret = 0;
4269         u64 page_start;
4270         u64 page_end;
4271
4272         if ((offset & (blocksize - 1)) == 0 &&
4273             (!len || ((len & (blocksize - 1)) == 0)))
4274                 goto out;
4275         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4276         if (ret)
4277                 goto out;
4278
4279 again:
4280         page = find_or_create_page(mapping, index, mask);
4281         if (!page) {
4282                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4283                 ret = -ENOMEM;
4284                 goto out;
4285         }
4286
4287         page_start = page_offset(page);
4288         page_end = page_start + PAGE_CACHE_SIZE - 1;
4289
4290         if (!PageUptodate(page)) {
4291                 ret = btrfs_readpage(NULL, page);
4292                 lock_page(page);
4293                 if (page->mapping != mapping) {
4294                         unlock_page(page);
4295                         page_cache_release(page);
4296                         goto again;
4297                 }
4298                 if (!PageUptodate(page)) {
4299                         ret = -EIO;
4300                         goto out_unlock;
4301                 }
4302         }
4303         wait_on_page_writeback(page);
4304
4305         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4306         set_page_extent_mapped(page);
4307
4308         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4309         if (ordered) {
4310                 unlock_extent_cached(io_tree, page_start, page_end,
4311                                      &cached_state, GFP_NOFS);
4312                 unlock_page(page);
4313                 page_cache_release(page);
4314                 btrfs_start_ordered_extent(inode, ordered, 1);
4315                 btrfs_put_ordered_extent(ordered);
4316                 goto again;
4317         }
4318
4319         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4320                           EXTENT_DIRTY | EXTENT_DELALLOC |
4321                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4322                           0, 0, &cached_state, GFP_NOFS);
4323
4324         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4325                                         &cached_state);
4326         if (ret) {
4327                 unlock_extent_cached(io_tree, page_start, page_end,
4328                                      &cached_state, GFP_NOFS);
4329                 goto out_unlock;
4330         }
4331
4332         if (offset != PAGE_CACHE_SIZE) {
4333                 if (!len)
4334                         len = PAGE_CACHE_SIZE - offset;
4335                 kaddr = kmap(page);
4336                 if (front)
4337                         memset(kaddr, 0, offset);
4338                 else
4339                         memset(kaddr + offset, 0, len);
4340                 flush_dcache_page(page);
4341                 kunmap(page);
4342         }
4343         ClearPageChecked(page);
4344         set_page_dirty(page);
4345         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4346                              GFP_NOFS);
4347
4348 out_unlock:
4349         if (ret)
4350                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4351         unlock_page(page);
4352         page_cache_release(page);
4353 out:
4354         return ret;
4355 }
4356
4357 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4358                              u64 offset, u64 len)
4359 {
4360         struct btrfs_trans_handle *trans;
4361         int ret;
4362
4363         /*
4364          * Still need to make sure the inode looks like it's been updated so
4365          * that any holes get logged if we fsync.
4366          */
4367         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4368                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4369                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4370                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4371                 return 0;
4372         }
4373
4374         /*
4375          * 1 - for the one we're dropping
4376          * 1 - for the one we're adding
4377          * 1 - for updating the inode.
4378          */
4379         trans = btrfs_start_transaction(root, 3);
4380         if (IS_ERR(trans))
4381                 return PTR_ERR(trans);
4382
4383         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4384         if (ret) {
4385                 btrfs_abort_transaction(trans, root, ret);
4386                 btrfs_end_transaction(trans, root);
4387                 return ret;
4388         }
4389
4390         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4391                                        0, 0, len, 0, len, 0, 0, 0);
4392         if (ret)
4393                 btrfs_abort_transaction(trans, root, ret);
4394         else
4395                 btrfs_update_inode(trans, root, inode);
4396         btrfs_end_transaction(trans, root);
4397         return ret;
4398 }
4399
4400 /*
4401  * This function puts in dummy file extents for the area we're creating a hole
4402  * for.  So if we are truncating this file to a larger size we need to insert
4403  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4404  * the range between oldsize and size
4405  */
4406 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4407 {
4408         struct btrfs_root *root = BTRFS_I(inode)->root;
4409         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4410         struct extent_map *em = NULL;
4411         struct extent_state *cached_state = NULL;
4412         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4413         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4414         u64 block_end = ALIGN(size, root->sectorsize);
4415         u64 last_byte;
4416         u64 cur_offset;
4417         u64 hole_size;
4418         int err = 0;
4419
4420         /*
4421          * If our size started in the middle of a page we need to zero out the
4422          * rest of the page before we expand the i_size, otherwise we could
4423          * expose stale data.
4424          */
4425         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4426         if (err)
4427                 return err;
4428
4429         if (size <= hole_start)
4430                 return 0;
4431
4432         while (1) {
4433                 struct btrfs_ordered_extent *ordered;
4434
4435                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4436                                  &cached_state);
4437                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4438                                                      block_end - hole_start);
4439                 if (!ordered)
4440                         break;
4441                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4442                                      &cached_state, GFP_NOFS);
4443                 btrfs_start_ordered_extent(inode, ordered, 1);
4444                 btrfs_put_ordered_extent(ordered);
4445         }
4446
4447         cur_offset = hole_start;
4448         while (1) {
4449                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4450                                 block_end - cur_offset, 0);
4451                 if (IS_ERR(em)) {
4452                         err = PTR_ERR(em);
4453                         em = NULL;
4454                         break;
4455                 }
4456                 last_byte = min(extent_map_end(em), block_end);
4457                 last_byte = ALIGN(last_byte , root->sectorsize);
4458                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4459                         struct extent_map *hole_em;
4460                         hole_size = last_byte - cur_offset;
4461
4462                         err = maybe_insert_hole(root, inode, cur_offset,
4463                                                 hole_size);
4464                         if (err)
4465                                 break;
4466                         btrfs_drop_extent_cache(inode, cur_offset,
4467                                                 cur_offset + hole_size - 1, 0);
4468                         hole_em = alloc_extent_map();
4469                         if (!hole_em) {
4470                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4471                                         &BTRFS_I(inode)->runtime_flags);
4472                                 goto next;
4473                         }
4474                         hole_em->start = cur_offset;
4475                         hole_em->len = hole_size;
4476                         hole_em->orig_start = cur_offset;
4477
4478                         hole_em->block_start = EXTENT_MAP_HOLE;
4479                         hole_em->block_len = 0;
4480                         hole_em->orig_block_len = 0;
4481                         hole_em->ram_bytes = hole_size;
4482                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4483                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4484                         hole_em->generation = root->fs_info->generation;
4485
4486                         while (1) {
4487                                 write_lock(&em_tree->lock);
4488                                 err = add_extent_mapping(em_tree, hole_em, 1);
4489                                 write_unlock(&em_tree->lock);
4490                                 if (err != -EEXIST)
4491                                         break;
4492                                 btrfs_drop_extent_cache(inode, cur_offset,
4493                                                         cur_offset +
4494                                                         hole_size - 1, 0);
4495                         }
4496                         free_extent_map(hole_em);
4497                 }
4498 next:
4499                 free_extent_map(em);
4500                 em = NULL;
4501                 cur_offset = last_byte;
4502                 if (cur_offset >= block_end)
4503                         break;
4504         }
4505         free_extent_map(em);
4506         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4507                              GFP_NOFS);
4508         return err;
4509 }
4510
4511 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4512 {
4513         struct btrfs_root *root = BTRFS_I(inode)->root;
4514         struct btrfs_trans_handle *trans;
4515         loff_t oldsize = i_size_read(inode);
4516         loff_t newsize = attr->ia_size;
4517         int mask = attr->ia_valid;
4518         int ret;
4519
4520         /*
4521          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4522          * special case where we need to update the times despite not having
4523          * these flags set.  For all other operations the VFS set these flags
4524          * explicitly if it wants a timestamp update.
4525          */
4526         if (newsize != oldsize) {
4527                 inode_inc_iversion(inode);
4528                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4529                         inode->i_ctime = inode->i_mtime =
4530                                 current_fs_time(inode->i_sb);
4531         }
4532
4533         if (newsize > oldsize) {
4534                 truncate_pagecache(inode, newsize);
4535                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4536                 if (ret)
4537                         return ret;
4538
4539                 trans = btrfs_start_transaction(root, 1);
4540                 if (IS_ERR(trans))
4541                         return PTR_ERR(trans);
4542
4543                 i_size_write(inode, newsize);
4544                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4545                 ret = btrfs_update_inode(trans, root, inode);
4546                 btrfs_end_transaction(trans, root);
4547         } else {
4548
4549                 /*
4550                  * We're truncating a file that used to have good data down to
4551                  * zero. Make sure it gets into the ordered flush list so that
4552                  * any new writes get down to disk quickly.
4553                  */
4554                 if (newsize == 0)
4555                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4556                                 &BTRFS_I(inode)->runtime_flags);
4557
4558                 /*
4559                  * 1 for the orphan item we're going to add
4560                  * 1 for the orphan item deletion.
4561                  */
4562                 trans = btrfs_start_transaction(root, 2);
4563                 if (IS_ERR(trans))
4564                         return PTR_ERR(trans);
4565
4566                 /*
4567                  * We need to do this in case we fail at _any_ point during the
4568                  * actual truncate.  Once we do the truncate_setsize we could
4569                  * invalidate pages which forces any outstanding ordered io to
4570                  * be instantly completed which will give us extents that need
4571                  * to be truncated.  If we fail to get an orphan inode down we
4572                  * could have left over extents that were never meant to live,
4573                  * so we need to garuntee from this point on that everything
4574                  * will be consistent.
4575                  */
4576                 ret = btrfs_orphan_add(trans, inode);
4577                 btrfs_end_transaction(trans, root);
4578                 if (ret)
4579                         return ret;
4580
4581                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4582                 truncate_setsize(inode, newsize);
4583
4584                 /* Disable nonlocked read DIO to avoid the end less truncate */
4585                 btrfs_inode_block_unlocked_dio(inode);
4586                 inode_dio_wait(inode);
4587                 btrfs_inode_resume_unlocked_dio(inode);
4588
4589                 ret = btrfs_truncate(inode);
4590                 if (ret && inode->i_nlink) {
4591                         int err;
4592
4593                         /*
4594                          * failed to truncate, disk_i_size is only adjusted down
4595                          * as we remove extents, so it should represent the true
4596                          * size of the inode, so reset the in memory size and
4597                          * delete our orphan entry.
4598                          */
4599                         trans = btrfs_join_transaction(root);
4600                         if (IS_ERR(trans)) {
4601                                 btrfs_orphan_del(NULL, inode);
4602                                 return ret;
4603                         }
4604                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4605                         err = btrfs_orphan_del(trans, inode);
4606                         if (err)
4607                                 btrfs_abort_transaction(trans, root, err);
4608                         btrfs_end_transaction(trans, root);
4609                 }
4610         }
4611
4612         return ret;
4613 }
4614
4615 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4616 {
4617         struct inode *inode = dentry->d_inode;
4618         struct btrfs_root *root = BTRFS_I(inode)->root;
4619         int err;
4620
4621         if (btrfs_root_readonly(root))
4622                 return -EROFS;
4623
4624         err = inode_change_ok(inode, attr);
4625         if (err)
4626                 return err;
4627
4628         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4629                 err = btrfs_setsize(inode, attr);
4630                 if (err)
4631                         return err;
4632         }
4633
4634         if (attr->ia_valid) {
4635                 setattr_copy(inode, attr);
4636                 inode_inc_iversion(inode);
4637                 err = btrfs_dirty_inode(inode);
4638
4639                 if (!err && attr->ia_valid & ATTR_MODE)
4640                         err = posix_acl_chmod(inode, inode->i_mode);
4641         }
4642
4643         return err;
4644 }
4645
4646 /*
4647  * While truncating the inode pages during eviction, we get the VFS calling
4648  * btrfs_invalidatepage() against each page of the inode. This is slow because
4649  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4650  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4651  * extent_state structures over and over, wasting lots of time.
4652  *
4653  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4654  * those expensive operations on a per page basis and do only the ordered io
4655  * finishing, while we release here the extent_map and extent_state structures,
4656  * without the excessive merging and splitting.
4657  */
4658 static void evict_inode_truncate_pages(struct inode *inode)
4659 {
4660         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4661         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4662         struct rb_node *node;
4663
4664         ASSERT(inode->i_state & I_FREEING);
4665         truncate_inode_pages_final(&inode->i_data);
4666
4667         write_lock(&map_tree->lock);
4668         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4669                 struct extent_map *em;
4670
4671                 node = rb_first(&map_tree->map);
4672                 em = rb_entry(node, struct extent_map, rb_node);
4673                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4674                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4675                 remove_extent_mapping(map_tree, em);
4676                 free_extent_map(em);
4677                 if (need_resched()) {
4678                         write_unlock(&map_tree->lock);
4679                         cond_resched();
4680                         write_lock(&map_tree->lock);
4681                 }
4682         }
4683         write_unlock(&map_tree->lock);
4684
4685         spin_lock(&io_tree->lock);
4686         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4687                 struct extent_state *state;
4688                 struct extent_state *cached_state = NULL;
4689
4690                 node = rb_first(&io_tree->state);
4691                 state = rb_entry(node, struct extent_state, rb_node);
4692                 atomic_inc(&state->refs);
4693                 spin_unlock(&io_tree->lock);
4694
4695                 lock_extent_bits(io_tree, state->start, state->end,
4696                                  0, &cached_state);
4697                 clear_extent_bit(io_tree, state->start, state->end,
4698                                  EXTENT_LOCKED | EXTENT_DIRTY |
4699                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4700                                  EXTENT_DEFRAG, 1, 1,
4701                                  &cached_state, GFP_NOFS);
4702                 free_extent_state(state);
4703
4704                 cond_resched();
4705                 spin_lock(&io_tree->lock);
4706         }
4707         spin_unlock(&io_tree->lock);
4708 }
4709
4710 void btrfs_evict_inode(struct inode *inode)
4711 {
4712         struct btrfs_trans_handle *trans;
4713         struct btrfs_root *root = BTRFS_I(inode)->root;
4714         struct btrfs_block_rsv *rsv, *global_rsv;
4715         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4716         int ret;
4717
4718         trace_btrfs_inode_evict(inode);
4719
4720         evict_inode_truncate_pages(inode);
4721
4722         if (inode->i_nlink &&
4723             ((btrfs_root_refs(&root->root_item) != 0 &&
4724               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4725              btrfs_is_free_space_inode(inode)))
4726                 goto no_delete;
4727
4728         if (is_bad_inode(inode)) {
4729                 btrfs_orphan_del(NULL, inode);
4730                 goto no_delete;
4731         }
4732         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4733         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4734
4735         if (root->fs_info->log_root_recovering) {
4736                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4737                                  &BTRFS_I(inode)->runtime_flags));
4738                 goto no_delete;
4739         }
4740
4741         if (inode->i_nlink > 0) {
4742                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4743                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4744                 goto no_delete;
4745         }
4746
4747         ret = btrfs_commit_inode_delayed_inode(inode);
4748         if (ret) {
4749                 btrfs_orphan_del(NULL, inode);
4750                 goto no_delete;
4751         }
4752
4753         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4754         if (!rsv) {
4755                 btrfs_orphan_del(NULL, inode);
4756                 goto no_delete;
4757         }
4758         rsv->size = min_size;
4759         rsv->failfast = 1;
4760         global_rsv = &root->fs_info->global_block_rsv;
4761
4762         btrfs_i_size_write(inode, 0);
4763
4764         /*
4765          * This is a bit simpler than btrfs_truncate since we've already
4766          * reserved our space for our orphan item in the unlink, so we just
4767          * need to reserve some slack space in case we add bytes and update
4768          * inode item when doing the truncate.
4769          */
4770         while (1) {
4771                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4772                                              BTRFS_RESERVE_FLUSH_LIMIT);
4773
4774                 /*
4775                  * Try and steal from the global reserve since we will
4776                  * likely not use this space anyway, we want to try as
4777                  * hard as possible to get this to work.
4778                  */
4779                 if (ret)
4780                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4781
4782                 if (ret) {
4783                         btrfs_warn(root->fs_info,
4784                                 "Could not get space for a delete, will truncate on mount %d",
4785                                 ret);
4786                         btrfs_orphan_del(NULL, inode);
4787                         btrfs_free_block_rsv(root, rsv);
4788                         goto no_delete;
4789                 }
4790
4791                 trans = btrfs_join_transaction(root);
4792                 if (IS_ERR(trans)) {
4793                         btrfs_orphan_del(NULL, inode);
4794                         btrfs_free_block_rsv(root, rsv);
4795                         goto no_delete;
4796                 }
4797
4798                 trans->block_rsv = rsv;
4799
4800                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4801                 if (ret != -ENOSPC)
4802                         break;
4803
4804                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4805                 btrfs_end_transaction(trans, root);
4806                 trans = NULL;
4807                 btrfs_btree_balance_dirty(root);
4808         }
4809
4810         btrfs_free_block_rsv(root, rsv);
4811
4812         /*
4813          * Errors here aren't a big deal, it just means we leave orphan items
4814          * in the tree.  They will be cleaned up on the next mount.
4815          */
4816         if (ret == 0) {
4817                 trans->block_rsv = root->orphan_block_rsv;
4818                 btrfs_orphan_del(trans, inode);
4819         } else {
4820                 btrfs_orphan_del(NULL, inode);
4821         }
4822
4823         trans->block_rsv = &root->fs_info->trans_block_rsv;
4824         if (!(root == root->fs_info->tree_root ||
4825               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4826                 btrfs_return_ino(root, btrfs_ino(inode));
4827
4828         btrfs_end_transaction(trans, root);
4829         btrfs_btree_balance_dirty(root);
4830 no_delete:
4831         btrfs_remove_delayed_node(inode);
4832         clear_inode(inode);
4833         return;
4834 }
4835
4836 /*
4837  * this returns the key found in the dir entry in the location pointer.
4838  * If no dir entries were found, location->objectid is 0.
4839  */
4840 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4841                                struct btrfs_key *location)
4842 {
4843         const char *name = dentry->d_name.name;
4844         int namelen = dentry->d_name.len;
4845         struct btrfs_dir_item *di;
4846         struct btrfs_path *path;
4847         struct btrfs_root *root = BTRFS_I(dir)->root;
4848         int ret = 0;
4849
4850         path = btrfs_alloc_path();
4851         if (!path)
4852                 return -ENOMEM;
4853
4854         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4855                                     namelen, 0);
4856         if (IS_ERR(di))
4857                 ret = PTR_ERR(di);
4858
4859         if (IS_ERR_OR_NULL(di))
4860                 goto out_err;
4861
4862         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4863 out:
4864         btrfs_free_path(path);
4865         return ret;
4866 out_err:
4867         location->objectid = 0;
4868         goto out;
4869 }
4870
4871 /*
4872  * when we hit a tree root in a directory, the btrfs part of the inode
4873  * needs to be changed to reflect the root directory of the tree root.  This
4874  * is kind of like crossing a mount point.
4875  */
4876 static int fixup_tree_root_location(struct btrfs_root *root,
4877                                     struct inode *dir,
4878                                     struct dentry *dentry,
4879                                     struct btrfs_key *location,
4880                                     struct btrfs_root **sub_root)
4881 {
4882         struct btrfs_path *path;
4883         struct btrfs_root *new_root;
4884         struct btrfs_root_ref *ref;
4885         struct extent_buffer *leaf;
4886         int ret;
4887         int err = 0;
4888
4889         path = btrfs_alloc_path();
4890         if (!path) {
4891                 err = -ENOMEM;
4892                 goto out;
4893         }
4894
4895         err = -ENOENT;
4896         ret = btrfs_find_item(root->fs_info->tree_root, path,
4897                                 BTRFS_I(dir)->root->root_key.objectid,
4898                                 location->objectid, BTRFS_ROOT_REF_KEY, NULL);
4899         if (ret) {
4900                 if (ret < 0)
4901                         err = ret;
4902                 goto out;
4903         }
4904
4905         leaf = path->nodes[0];
4906         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
4907         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
4908             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
4909                 goto out;
4910
4911         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
4912                                    (unsigned long)(ref + 1),
4913                                    dentry->d_name.len);
4914         if (ret)
4915                 goto out;
4916
4917         btrfs_release_path(path);
4918
4919         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
4920         if (IS_ERR(new_root)) {
4921                 err = PTR_ERR(new_root);
4922                 goto out;
4923         }
4924
4925         *sub_root = new_root;
4926         location->objectid = btrfs_root_dirid(&new_root->root_item);
4927         location->type = BTRFS_INODE_ITEM_KEY;
4928         location->offset = 0;
4929         err = 0;
4930 out:
4931         btrfs_free_path(path);
4932         return err;
4933 }
4934
4935 static void inode_tree_add(struct inode *inode)
4936 {
4937         struct btrfs_root *root = BTRFS_I(inode)->root;
4938         struct btrfs_inode *entry;
4939         struct rb_node **p;
4940         struct rb_node *parent;
4941         struct rb_node *new = &BTRFS_I(inode)->rb_node;
4942         u64 ino = btrfs_ino(inode);
4943
4944         if (inode_unhashed(inode))
4945                 return;
4946         parent = NULL;
4947         spin_lock(&root->inode_lock);
4948         p = &root->inode_tree.rb_node;
4949         while (*p) {
4950                 parent = *p;
4951                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
4952
4953                 if (ino < btrfs_ino(&entry->vfs_inode))
4954                         p = &parent->rb_left;
4955                 else if (ino > btrfs_ino(&entry->vfs_inode))
4956                         p = &parent->rb_right;
4957                 else {
4958                         WARN_ON(!(entry->vfs_inode.i_state &
4959                                   (I_WILL_FREE | I_FREEING)));
4960                         rb_replace_node(parent, new, &root->inode_tree);
4961                         RB_CLEAR_NODE(parent);
4962                         spin_unlock(&root->inode_lock);
4963                         return;
4964                 }
4965         }
4966         rb_link_node(new, parent, p);
4967         rb_insert_color(new, &root->inode_tree);
4968         spin_unlock(&root->inode_lock);
4969 }
4970
4971 static void inode_tree_del(struct inode *inode)
4972 {
4973         struct btrfs_root *root = BTRFS_I(inode)->root;
4974         int empty = 0;
4975
4976         spin_lock(&root->inode_lock);
4977         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
4978                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
4979                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
4980                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4981         }
4982         spin_unlock(&root->inode_lock);
4983
4984         if (empty && btrfs_root_refs(&root->root_item) == 0) {
4985                 synchronize_srcu(&root->fs_info->subvol_srcu);
4986                 spin_lock(&root->inode_lock);
4987                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4988                 spin_unlock(&root->inode_lock);
4989                 if (empty)
4990                         btrfs_add_dead_root(root);
4991         }
4992 }
4993
4994 void btrfs_invalidate_inodes(struct btrfs_root *root)
4995 {
4996         struct rb_node *node;
4997         struct rb_node *prev;
4998         struct btrfs_inode *entry;
4999         struct inode *inode;
5000         u64 objectid = 0;
5001
5002         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
5003                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5004
5005         spin_lock(&root->inode_lock);
5006 again:
5007         node = root->inode_tree.rb_node;
5008         prev = NULL;
5009         while (node) {
5010                 prev = node;
5011                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5012
5013                 if (objectid < btrfs_ino(&entry->vfs_inode))
5014                         node = node->rb_left;
5015                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5016                         node = node->rb_right;
5017                 else
5018                         break;
5019         }
5020         if (!node) {
5021                 while (prev) {
5022                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5023                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5024                                 node = prev;
5025                                 break;
5026                         }
5027                         prev = rb_next(prev);
5028                 }
5029         }
5030         while (node) {
5031                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5032                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5033                 inode = igrab(&entry->vfs_inode);
5034                 if (inode) {
5035                         spin_unlock(&root->inode_lock);
5036                         if (atomic_read(&inode->i_count) > 1)
5037                                 d_prune_aliases(inode);
5038                         /*
5039                          * btrfs_drop_inode will have it removed from
5040                          * the inode cache when its usage count
5041                          * hits zero.
5042                          */
5043                         iput(inode);
5044                         cond_resched();
5045                         spin_lock(&root->inode_lock);
5046                         goto again;
5047                 }
5048
5049                 if (cond_resched_lock(&root->inode_lock))
5050                         goto again;
5051
5052                 node = rb_next(node);
5053         }
5054         spin_unlock(&root->inode_lock);
5055 }
5056
5057 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5058 {
5059         struct btrfs_iget_args *args = p;
5060         inode->i_ino = args->location->objectid;
5061         memcpy(&BTRFS_I(inode)->location, args->location,
5062                sizeof(*args->location));
5063         BTRFS_I(inode)->root = args->root;
5064         return 0;
5065 }
5066
5067 static int btrfs_find_actor(struct inode *inode, void *opaque)
5068 {
5069         struct btrfs_iget_args *args = opaque;
5070         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5071                 args->root == BTRFS_I(inode)->root;
5072 }
5073
5074 static struct inode *btrfs_iget_locked(struct super_block *s,
5075                                        struct btrfs_key *location,
5076                                        struct btrfs_root *root)
5077 {
5078         struct inode *inode;
5079         struct btrfs_iget_args args;
5080         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5081
5082         args.location = location;
5083         args.root = root;
5084
5085         inode = iget5_locked(s, hashval, btrfs_find_actor,
5086                              btrfs_init_locked_inode,
5087                              (void *)&args);
5088         return inode;
5089 }
5090
5091 /* Get an inode object given its location and corresponding root.
5092  * Returns in *is_new if the inode was read from disk
5093  */
5094 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5095                          struct btrfs_root *root, int *new)
5096 {
5097         struct inode *inode;
5098
5099         inode = btrfs_iget_locked(s, location, root);
5100         if (!inode)
5101                 return ERR_PTR(-ENOMEM);
5102
5103         if (inode->i_state & I_NEW) {
5104                 btrfs_read_locked_inode(inode);
5105                 if (!is_bad_inode(inode)) {
5106                         inode_tree_add(inode);
5107                         unlock_new_inode(inode);
5108                         if (new)
5109                                 *new = 1;
5110                 } else {
5111                         unlock_new_inode(inode);
5112                         iput(inode);
5113                         inode = ERR_PTR(-ESTALE);
5114                 }
5115         }
5116
5117         return inode;
5118 }
5119
5120 static struct inode *new_simple_dir(struct super_block *s,
5121                                     struct btrfs_key *key,
5122                                     struct btrfs_root *root)
5123 {
5124         struct inode *inode = new_inode(s);
5125
5126         if (!inode)
5127                 return ERR_PTR(-ENOMEM);
5128
5129         BTRFS_I(inode)->root = root;
5130         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5131         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5132
5133         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5134         inode->i_op = &btrfs_dir_ro_inode_operations;
5135         inode->i_fop = &simple_dir_operations;
5136         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5137         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5138
5139         return inode;
5140 }
5141
5142 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5143 {
5144         struct inode *inode;
5145         struct btrfs_root *root = BTRFS_I(dir)->root;
5146         struct btrfs_root *sub_root = root;
5147         struct btrfs_key location;
5148         int index;
5149         int ret = 0;
5150
5151         if (dentry->d_name.len > BTRFS_NAME_LEN)
5152                 return ERR_PTR(-ENAMETOOLONG);
5153
5154         ret = btrfs_inode_by_name(dir, dentry, &location);
5155         if (ret < 0)
5156                 return ERR_PTR(ret);
5157
5158         if (location.objectid == 0)
5159                 return ERR_PTR(-ENOENT);
5160
5161         if (location.type == BTRFS_INODE_ITEM_KEY) {
5162                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5163                 return inode;
5164         }
5165
5166         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5167
5168         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5169         ret = fixup_tree_root_location(root, dir, dentry,
5170                                        &location, &sub_root);
5171         if (ret < 0) {
5172                 if (ret != -ENOENT)
5173                         inode = ERR_PTR(ret);
5174                 else
5175                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5176         } else {
5177                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5178         }
5179         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5180
5181         if (!IS_ERR(inode) && root != sub_root) {
5182                 down_read(&root->fs_info->cleanup_work_sem);
5183                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5184                         ret = btrfs_orphan_cleanup(sub_root);
5185                 up_read(&root->fs_info->cleanup_work_sem);
5186                 if (ret) {
5187                         iput(inode);
5188                         inode = ERR_PTR(ret);
5189                 }
5190                 /*
5191                  * If orphan cleanup did remove any orphans, it means the tree
5192                  * was modified and therefore the commit root is not the same as
5193                  * the current root anymore. This is a problem, because send
5194                  * uses the commit root and therefore can see inode items that
5195                  * don't exist in the current root anymore, and for example make
5196                  * calls to btrfs_iget, which will do tree lookups based on the
5197                  * current root and not on the commit root. Those lookups will
5198                  * fail, returning a -ESTALE error, and making send fail with
5199                  * that error. So make sure a send does not see any orphans we
5200                  * have just removed, and that it will see the same inodes
5201                  * regardless of whether a transaction commit happened before
5202                  * it started (meaning that the commit root will be the same as
5203                  * the current root) or not.
5204                  */
5205                 if (sub_root->node != sub_root->commit_root) {
5206                         u64 sub_flags = btrfs_root_flags(&sub_root->root_item);
5207
5208                         if (sub_flags & BTRFS_ROOT_SUBVOL_RDONLY) {
5209                                 struct extent_buffer *eb;
5210
5211                                 /*
5212                                  * Assert we can't have races between dentry
5213                                  * lookup called through the snapshot creation
5214                                  * ioctl and the VFS.
5215                                  */
5216                                 ASSERT(mutex_is_locked(&dir->i_mutex));
5217
5218                                 down_write(&root->fs_info->commit_root_sem);
5219                                 eb = sub_root->commit_root;
5220                                 sub_root->commit_root =
5221                                         btrfs_root_node(sub_root);
5222                                 up_write(&root->fs_info->commit_root_sem);
5223                                 free_extent_buffer(eb);
5224                         }
5225                 }
5226         }
5227
5228         return inode;
5229 }
5230
5231 static int btrfs_dentry_delete(const struct dentry *dentry)
5232 {
5233         struct btrfs_root *root;
5234         struct inode *inode = dentry->d_inode;
5235
5236         if (!inode && !IS_ROOT(dentry))
5237                 inode = dentry->d_parent->d_inode;
5238
5239         if (inode) {
5240                 root = BTRFS_I(inode)->root;
5241                 if (btrfs_root_refs(&root->root_item) == 0)
5242                         return 1;
5243
5244                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5245                         return 1;
5246         }
5247         return 0;
5248 }
5249
5250 static void btrfs_dentry_release(struct dentry *dentry)
5251 {
5252         kfree(dentry->d_fsdata);
5253 }
5254
5255 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5256                                    unsigned int flags)
5257 {
5258         struct inode *inode;
5259
5260         inode = btrfs_lookup_dentry(dir, dentry);
5261         if (IS_ERR(inode)) {
5262                 if (PTR_ERR(inode) == -ENOENT)
5263                         inode = NULL;
5264                 else
5265                         return ERR_CAST(inode);
5266         }
5267
5268         return d_materialise_unique(dentry, inode);
5269 }
5270
5271 unsigned char btrfs_filetype_table[] = {
5272         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5273 };
5274
5275 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5276 {
5277         struct inode *inode = file_inode(file);
5278         struct btrfs_root *root = BTRFS_I(inode)->root;
5279         struct btrfs_item *item;
5280         struct btrfs_dir_item *di;
5281         struct btrfs_key key;
5282         struct btrfs_key found_key;
5283         struct btrfs_path *path;
5284         struct list_head ins_list;
5285         struct list_head del_list;
5286         int ret;
5287         struct extent_buffer *leaf;
5288         int slot;
5289         unsigned char d_type;
5290         int over = 0;
5291         u32 di_cur;
5292         u32 di_total;
5293         u32 di_len;
5294         int key_type = BTRFS_DIR_INDEX_KEY;
5295         char tmp_name[32];
5296         char *name_ptr;
5297         int name_len;
5298         int is_curr = 0;        /* ctx->pos points to the current index? */
5299
5300         /* FIXME, use a real flag for deciding about the key type */
5301         if (root->fs_info->tree_root == root)
5302                 key_type = BTRFS_DIR_ITEM_KEY;
5303
5304         if (!dir_emit_dots(file, ctx))
5305                 return 0;
5306
5307         path = btrfs_alloc_path();
5308         if (!path)
5309                 return -ENOMEM;
5310
5311         path->reada = 1;
5312
5313         if (key_type == BTRFS_DIR_INDEX_KEY) {
5314                 INIT_LIST_HEAD(&ins_list);
5315                 INIT_LIST_HEAD(&del_list);
5316                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5317         }
5318
5319         btrfs_set_key_type(&key, key_type);
5320         key.offset = ctx->pos;
5321         key.objectid = btrfs_ino(inode);
5322
5323         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5324         if (ret < 0)
5325                 goto err;
5326
5327         while (1) {
5328                 leaf = path->nodes[0];
5329                 slot = path->slots[0];
5330                 if (slot >= btrfs_header_nritems(leaf)) {
5331                         ret = btrfs_next_leaf(root, path);
5332                         if (ret < 0)
5333                                 goto err;
5334                         else if (ret > 0)
5335                                 break;
5336                         continue;
5337                 }
5338
5339                 item = btrfs_item_nr(slot);
5340                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5341
5342                 if (found_key.objectid != key.objectid)
5343                         break;
5344                 if (btrfs_key_type(&found_key) != key_type)
5345                         break;
5346                 if (found_key.offset < ctx->pos)
5347                         goto next;
5348                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5349                     btrfs_should_delete_dir_index(&del_list,
5350                                                   found_key.offset))
5351                         goto next;
5352
5353                 ctx->pos = found_key.offset;
5354                 is_curr = 1;
5355
5356                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5357                 di_cur = 0;
5358                 di_total = btrfs_item_size(leaf, item);
5359
5360                 while (di_cur < di_total) {
5361                         struct btrfs_key location;
5362
5363                         if (verify_dir_item(root, leaf, di))
5364                                 break;
5365
5366                         name_len = btrfs_dir_name_len(leaf, di);
5367                         if (name_len <= sizeof(tmp_name)) {
5368                                 name_ptr = tmp_name;
5369                         } else {
5370                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5371                                 if (!name_ptr) {
5372                                         ret = -ENOMEM;
5373                                         goto err;
5374                                 }
5375                         }
5376                         read_extent_buffer(leaf, name_ptr,
5377                                            (unsigned long)(di + 1), name_len);
5378
5379                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5380                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5381
5382
5383                         /* is this a reference to our own snapshot? If so
5384                          * skip it.
5385                          *
5386                          * In contrast to old kernels, we insert the snapshot's
5387                          * dir item and dir index after it has been created, so
5388                          * we won't find a reference to our own snapshot. We
5389                          * still keep the following code for backward
5390                          * compatibility.
5391                          */
5392                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5393                             location.objectid == root->root_key.objectid) {
5394                                 over = 0;
5395                                 goto skip;
5396                         }
5397                         over = !dir_emit(ctx, name_ptr, name_len,
5398                                        location.objectid, d_type);
5399
5400 skip:
5401                         if (name_ptr != tmp_name)
5402                                 kfree(name_ptr);
5403
5404                         if (over)
5405                                 goto nopos;
5406                         di_len = btrfs_dir_name_len(leaf, di) +
5407                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5408                         di_cur += di_len;
5409                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5410                 }
5411 next:
5412                 path->slots[0]++;
5413         }
5414
5415         if (key_type == BTRFS_DIR_INDEX_KEY) {
5416                 if (is_curr)
5417                         ctx->pos++;
5418                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5419                 if (ret)
5420                         goto nopos;
5421         }
5422
5423         /* Reached end of directory/root. Bump pos past the last item. */
5424         ctx->pos++;
5425
5426         /*
5427          * Stop new entries from being returned after we return the last
5428          * entry.
5429          *
5430          * New directory entries are assigned a strictly increasing
5431          * offset.  This means that new entries created during readdir
5432          * are *guaranteed* to be seen in the future by that readdir.
5433          * This has broken buggy programs which operate on names as
5434          * they're returned by readdir.  Until we re-use freed offsets
5435          * we have this hack to stop new entries from being returned
5436          * under the assumption that they'll never reach this huge
5437          * offset.
5438          *
5439          * This is being careful not to overflow 32bit loff_t unless the
5440          * last entry requires it because doing so has broken 32bit apps
5441          * in the past.
5442          */
5443         if (key_type == BTRFS_DIR_INDEX_KEY) {
5444                 if (ctx->pos >= INT_MAX)
5445                         ctx->pos = LLONG_MAX;
5446                 else
5447                         ctx->pos = INT_MAX;
5448         }
5449 nopos:
5450         ret = 0;
5451 err:
5452         if (key_type == BTRFS_DIR_INDEX_KEY)
5453                 btrfs_put_delayed_items(&ins_list, &del_list);
5454         btrfs_free_path(path);
5455         return ret;
5456 }
5457
5458 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5459 {
5460         struct btrfs_root *root = BTRFS_I(inode)->root;
5461         struct btrfs_trans_handle *trans;
5462         int ret = 0;
5463         bool nolock = false;
5464
5465         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5466                 return 0;
5467
5468         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5469                 nolock = true;
5470
5471         if (wbc->sync_mode == WB_SYNC_ALL) {
5472                 if (nolock)
5473                         trans = btrfs_join_transaction_nolock(root);
5474                 else
5475                         trans = btrfs_join_transaction(root);
5476                 if (IS_ERR(trans))
5477                         return PTR_ERR(trans);
5478                 ret = btrfs_commit_transaction(trans, root);
5479         }
5480         return ret;
5481 }
5482
5483 /*
5484  * This is somewhat expensive, updating the tree every time the
5485  * inode changes.  But, it is most likely to find the inode in cache.
5486  * FIXME, needs more benchmarking...there are no reasons other than performance
5487  * to keep or drop this code.
5488  */
5489 static int btrfs_dirty_inode(struct inode *inode)
5490 {
5491         struct btrfs_root *root = BTRFS_I(inode)->root;
5492         struct btrfs_trans_handle *trans;
5493         int ret;
5494
5495         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5496                 return 0;
5497
5498         trans = btrfs_join_transaction(root);
5499         if (IS_ERR(trans))
5500                 return PTR_ERR(trans);
5501
5502         ret = btrfs_update_inode(trans, root, inode);
5503         if (ret && ret == -ENOSPC) {
5504                 /* whoops, lets try again with the full transaction */
5505                 btrfs_end_transaction(trans, root);
5506                 trans = btrfs_start_transaction(root, 1);
5507                 if (IS_ERR(trans))
5508                         return PTR_ERR(trans);
5509
5510                 ret = btrfs_update_inode(trans, root, inode);
5511         }
5512         btrfs_end_transaction(trans, root);
5513         if (BTRFS_I(inode)->delayed_node)
5514                 btrfs_balance_delayed_items(root);
5515
5516         return ret;
5517 }
5518
5519 /*
5520  * This is a copy of file_update_time.  We need this so we can return error on
5521  * ENOSPC for updating the inode in the case of file write and mmap writes.
5522  */
5523 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5524                              int flags)
5525 {
5526         struct btrfs_root *root = BTRFS_I(inode)->root;
5527
5528         if (btrfs_root_readonly(root))
5529                 return -EROFS;
5530
5531         if (flags & S_VERSION)
5532                 inode_inc_iversion(inode);
5533         if (flags & S_CTIME)
5534                 inode->i_ctime = *now;
5535         if (flags & S_MTIME)
5536                 inode->i_mtime = *now;
5537         if (flags & S_ATIME)
5538                 inode->i_atime = *now;
5539         return btrfs_dirty_inode(inode);
5540 }
5541
5542 /*
5543  * find the highest existing sequence number in a directory
5544  * and then set the in-memory index_cnt variable to reflect
5545  * free sequence numbers
5546  */
5547 static int btrfs_set_inode_index_count(struct inode *inode)
5548 {
5549         struct btrfs_root *root = BTRFS_I(inode)->root;
5550         struct btrfs_key key, found_key;
5551         struct btrfs_path *path;
5552         struct extent_buffer *leaf;
5553         int ret;
5554
5555         key.objectid = btrfs_ino(inode);
5556         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
5557         key.offset = (u64)-1;
5558
5559         path = btrfs_alloc_path();
5560         if (!path)
5561                 return -ENOMEM;
5562
5563         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5564         if (ret < 0)
5565                 goto out;
5566         /* FIXME: we should be able to handle this */
5567         if (ret == 0)
5568                 goto out;
5569         ret = 0;
5570
5571         /*
5572          * MAGIC NUMBER EXPLANATION:
5573          * since we search a directory based on f_pos we have to start at 2
5574          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5575          * else has to start at 2
5576          */
5577         if (path->slots[0] == 0) {
5578                 BTRFS_I(inode)->index_cnt = 2;
5579                 goto out;
5580         }
5581
5582         path->slots[0]--;
5583
5584         leaf = path->nodes[0];
5585         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5586
5587         if (found_key.objectid != btrfs_ino(inode) ||
5588             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
5589                 BTRFS_I(inode)->index_cnt = 2;
5590                 goto out;
5591         }
5592
5593         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5594 out:
5595         btrfs_free_path(path);
5596         return ret;
5597 }
5598
5599 /*
5600  * helper to find a free sequence number in a given directory.  This current
5601  * code is very simple, later versions will do smarter things in the btree
5602  */
5603 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5604 {
5605         int ret = 0;
5606
5607         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5608                 ret = btrfs_inode_delayed_dir_index_count(dir);
5609                 if (ret) {
5610                         ret = btrfs_set_inode_index_count(dir);
5611                         if (ret)
5612                                 return ret;
5613                 }
5614         }
5615
5616         *index = BTRFS_I(dir)->index_cnt;
5617         BTRFS_I(dir)->index_cnt++;
5618
5619         return ret;
5620 }
5621
5622 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5623                                      struct btrfs_root *root,
5624                                      struct inode *dir,
5625                                      const char *name, int name_len,
5626                                      u64 ref_objectid, u64 objectid,
5627                                      umode_t mode, u64 *index)
5628 {
5629         struct inode *inode;
5630         struct btrfs_inode_item *inode_item;
5631         struct btrfs_key *location;
5632         struct btrfs_path *path;
5633         struct btrfs_inode_ref *ref;
5634         struct btrfs_key key[2];
5635         u32 sizes[2];
5636         int nitems = name ? 2 : 1;
5637         unsigned long ptr;
5638         int ret;
5639
5640         path = btrfs_alloc_path();
5641         if (!path)
5642                 return ERR_PTR(-ENOMEM);
5643
5644         inode = new_inode(root->fs_info->sb);
5645         if (!inode) {
5646                 btrfs_free_path(path);
5647                 return ERR_PTR(-ENOMEM);
5648         }
5649
5650         /*
5651          * O_TMPFILE, set link count to 0, so that after this point,
5652          * we fill in an inode item with the correct link count.
5653          */
5654         if (!name)
5655                 set_nlink(inode, 0);
5656
5657         /*
5658          * we have to initialize this early, so we can reclaim the inode
5659          * number if we fail afterwards in this function.
5660          */
5661         inode->i_ino = objectid;
5662
5663         if (dir && name) {
5664                 trace_btrfs_inode_request(dir);
5665
5666                 ret = btrfs_set_inode_index(dir, index);
5667                 if (ret) {
5668                         btrfs_free_path(path);
5669                         iput(inode);
5670                         return ERR_PTR(ret);
5671                 }
5672         } else if (dir) {
5673                 *index = 0;
5674         }
5675         /*
5676          * index_cnt is ignored for everything but a dir,
5677          * btrfs_get_inode_index_count has an explanation for the magic
5678          * number
5679          */
5680         BTRFS_I(inode)->index_cnt = 2;
5681         BTRFS_I(inode)->dir_index = *index;
5682         BTRFS_I(inode)->root = root;
5683         BTRFS_I(inode)->generation = trans->transid;
5684         inode->i_generation = BTRFS_I(inode)->generation;
5685
5686         /*
5687          * We could have gotten an inode number from somebody who was fsynced
5688          * and then removed in this same transaction, so let's just set full
5689          * sync since it will be a full sync anyway and this will blow away the
5690          * old info in the log.
5691          */
5692         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5693
5694         key[0].objectid = objectid;
5695         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
5696         key[0].offset = 0;
5697
5698         sizes[0] = sizeof(struct btrfs_inode_item);
5699
5700         if (name) {
5701                 /*
5702                  * Start new inodes with an inode_ref. This is slightly more
5703                  * efficient for small numbers of hard links since they will
5704                  * be packed into one item. Extended refs will kick in if we
5705                  * add more hard links than can fit in the ref item.
5706                  */
5707                 key[1].objectid = objectid;
5708                 btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
5709                 key[1].offset = ref_objectid;
5710
5711                 sizes[1] = name_len + sizeof(*ref);
5712         }
5713
5714         path->leave_spinning = 1;
5715         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
5716         if (ret != 0)
5717                 goto fail;
5718
5719         inode_init_owner(inode, dir, mode);
5720         inode_set_bytes(inode, 0);
5721         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5722         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5723                                   struct btrfs_inode_item);
5724         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5725                              sizeof(*inode_item));
5726         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5727
5728         if (name) {
5729                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5730                                      struct btrfs_inode_ref);
5731                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5732                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5733                 ptr = (unsigned long)(ref + 1);
5734                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
5735         }
5736
5737         btrfs_mark_buffer_dirty(path->nodes[0]);
5738         btrfs_free_path(path);
5739
5740         location = &BTRFS_I(inode)->location;
5741         location->objectid = objectid;
5742         location->offset = 0;
5743         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
5744
5745         btrfs_inherit_iflags(inode, dir);
5746
5747         if (S_ISREG(mode)) {
5748                 if (btrfs_test_opt(root, NODATASUM))
5749                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5750                 if (btrfs_test_opt(root, NODATACOW))
5751                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5752                                 BTRFS_INODE_NODATASUM;
5753         }
5754
5755         btrfs_insert_inode_hash(inode);
5756         inode_tree_add(inode);
5757
5758         trace_btrfs_inode_new(inode);
5759         btrfs_set_inode_last_trans(trans, inode);
5760
5761         btrfs_update_root_times(trans, root);
5762
5763         ret = btrfs_inode_inherit_props(trans, inode, dir);
5764         if (ret)
5765                 btrfs_err(root->fs_info,
5766                           "error inheriting props for ino %llu (root %llu): %d",
5767                           btrfs_ino(inode), root->root_key.objectid, ret);
5768
5769         return inode;
5770 fail:
5771         if (dir && name)
5772                 BTRFS_I(dir)->index_cnt--;
5773         btrfs_free_path(path);
5774         iput(inode);
5775         return ERR_PTR(ret);
5776 }
5777
5778 static inline u8 btrfs_inode_type(struct inode *inode)
5779 {
5780         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5781 }
5782
5783 /*
5784  * utility function to add 'inode' into 'parent_inode' with
5785  * a give name and a given sequence number.
5786  * if 'add_backref' is true, also insert a backref from the
5787  * inode to the parent directory.
5788  */
5789 int btrfs_add_link(struct btrfs_trans_handle *trans,
5790                    struct inode *parent_inode, struct inode *inode,
5791                    const char *name, int name_len, int add_backref, u64 index)
5792 {
5793         int ret = 0;
5794         struct btrfs_key key;
5795         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5796         u64 ino = btrfs_ino(inode);
5797         u64 parent_ino = btrfs_ino(parent_inode);
5798
5799         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5800                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5801         } else {
5802                 key.objectid = ino;
5803                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
5804                 key.offset = 0;
5805         }
5806
5807         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5808                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5809                                          key.objectid, root->root_key.objectid,
5810                                          parent_ino, index, name, name_len);
5811         } else if (add_backref) {
5812                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5813                                              parent_ino, index);
5814         }
5815
5816         /* Nothing to clean up yet */
5817         if (ret)
5818                 return ret;
5819
5820         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5821                                     parent_inode, &key,
5822                                     btrfs_inode_type(inode), index);
5823         if (ret == -EEXIST || ret == -EOVERFLOW)
5824                 goto fail_dir_item;
5825         else if (ret) {
5826                 btrfs_abort_transaction(trans, root, ret);
5827                 return ret;
5828         }
5829
5830         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5831                            name_len * 2);
5832         inode_inc_iversion(parent_inode);
5833         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5834         ret = btrfs_update_inode(trans, root, parent_inode);
5835         if (ret)
5836                 btrfs_abort_transaction(trans, root, ret);
5837         return ret;
5838
5839 fail_dir_item:
5840         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5841                 u64 local_index;
5842                 int err;
5843                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5844                                  key.objectid, root->root_key.objectid,
5845                                  parent_ino, &local_index, name, name_len);
5846
5847         } else if (add_backref) {
5848                 u64 local_index;
5849                 int err;
5850
5851                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5852                                           ino, parent_ino, &local_index);
5853         }
5854         return ret;
5855 }
5856
5857 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5858                             struct inode *dir, struct dentry *dentry,
5859                             struct inode *inode, int backref, u64 index)
5860 {
5861         int err = btrfs_add_link(trans, dir, inode,
5862                                  dentry->d_name.name, dentry->d_name.len,
5863                                  backref, index);
5864         if (err > 0)
5865                 err = -EEXIST;
5866         return err;
5867 }
5868
5869 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5870                         umode_t mode, dev_t rdev)
5871 {
5872         struct btrfs_trans_handle *trans;
5873         struct btrfs_root *root = BTRFS_I(dir)->root;
5874         struct inode *inode = NULL;
5875         int err;
5876         int drop_inode = 0;
5877         u64 objectid;
5878         u64 index = 0;
5879
5880         if (!new_valid_dev(rdev))
5881                 return -EINVAL;
5882
5883         /*
5884          * 2 for inode item and ref
5885          * 2 for dir items
5886          * 1 for xattr if selinux is on
5887          */
5888         trans = btrfs_start_transaction(root, 5);
5889         if (IS_ERR(trans))
5890                 return PTR_ERR(trans);
5891
5892         err = btrfs_find_free_ino(root, &objectid);
5893         if (err)
5894                 goto out_unlock;
5895
5896         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5897                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5898                                 mode, &index);
5899         if (IS_ERR(inode)) {
5900                 err = PTR_ERR(inode);
5901                 goto out_unlock;
5902         }
5903
5904         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5905         if (err) {
5906                 drop_inode = 1;
5907                 goto out_unlock;
5908         }
5909
5910         /*
5911         * If the active LSM wants to access the inode during
5912         * d_instantiate it needs these. Smack checks to see
5913         * if the filesystem supports xattrs by looking at the
5914         * ops vector.
5915         */
5916
5917         inode->i_op = &btrfs_special_inode_operations;
5918         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5919         if (err)
5920                 drop_inode = 1;
5921         else {
5922                 init_special_inode(inode, inode->i_mode, rdev);
5923                 btrfs_update_inode(trans, root, inode);
5924                 d_instantiate(dentry, inode);
5925         }
5926 out_unlock:
5927         btrfs_end_transaction(trans, root);
5928         btrfs_balance_delayed_items(root);
5929         btrfs_btree_balance_dirty(root);
5930         if (drop_inode) {
5931                 inode_dec_link_count(inode);
5932                 iput(inode);
5933         }
5934         return err;
5935 }
5936
5937 static int btrfs_create(struct inode *dir, struct dentry *dentry,
5938                         umode_t mode, bool excl)
5939 {
5940         struct btrfs_trans_handle *trans;
5941         struct btrfs_root *root = BTRFS_I(dir)->root;
5942         struct inode *inode = NULL;
5943         int drop_inode_on_err = 0;
5944         int err;
5945         u64 objectid;
5946         u64 index = 0;
5947
5948         /*
5949          * 2 for inode item and ref
5950          * 2 for dir items
5951          * 1 for xattr if selinux is on
5952          */
5953         trans = btrfs_start_transaction(root, 5);
5954         if (IS_ERR(trans))
5955                 return PTR_ERR(trans);
5956
5957         err = btrfs_find_free_ino(root, &objectid);
5958         if (err)
5959                 goto out_unlock;
5960
5961         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5962                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5963                                 mode, &index);
5964         if (IS_ERR(inode)) {
5965                 err = PTR_ERR(inode);
5966                 goto out_unlock;
5967         }
5968         drop_inode_on_err = 1;
5969
5970         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5971         if (err)
5972                 goto out_unlock;
5973
5974         err = btrfs_update_inode(trans, root, inode);
5975         if (err)
5976                 goto out_unlock;
5977
5978         /*
5979         * If the active LSM wants to access the inode during
5980         * d_instantiate it needs these. Smack checks to see
5981         * if the filesystem supports xattrs by looking at the
5982         * ops vector.
5983         */
5984         inode->i_fop = &btrfs_file_operations;
5985         inode->i_op = &btrfs_file_inode_operations;
5986
5987         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5988         if (err)
5989                 goto out_unlock;
5990
5991         inode->i_mapping->a_ops = &btrfs_aops;
5992         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5993         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
5994         d_instantiate(dentry, inode);
5995
5996 out_unlock:
5997         btrfs_end_transaction(trans, root);
5998         if (err && drop_inode_on_err) {
5999                 inode_dec_link_count(inode);
6000                 iput(inode);
6001         }
6002         btrfs_balance_delayed_items(root);
6003         btrfs_btree_balance_dirty(root);
6004         return err;
6005 }
6006
6007 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6008                       struct dentry *dentry)
6009 {
6010         struct btrfs_trans_handle *trans;
6011         struct btrfs_root *root = BTRFS_I(dir)->root;
6012         struct inode *inode = old_dentry->d_inode;
6013         u64 index;
6014         int err;
6015         int drop_inode = 0;
6016
6017         /* do not allow sys_link's with other subvols of the same device */
6018         if (root->objectid != BTRFS_I(inode)->root->objectid)
6019                 return -EXDEV;
6020
6021         if (inode->i_nlink >= BTRFS_LINK_MAX)
6022                 return -EMLINK;
6023
6024         err = btrfs_set_inode_index(dir, &index);
6025         if (err)
6026                 goto fail;
6027
6028         /*
6029          * 2 items for inode and inode ref
6030          * 2 items for dir items
6031          * 1 item for parent inode
6032          */
6033         trans = btrfs_start_transaction(root, 5);
6034         if (IS_ERR(trans)) {
6035                 err = PTR_ERR(trans);
6036                 goto fail;
6037         }
6038
6039         /* There are several dir indexes for this inode, clear the cache. */
6040         BTRFS_I(inode)->dir_index = 0ULL;
6041         inc_nlink(inode);
6042         inode_inc_iversion(inode);
6043         inode->i_ctime = CURRENT_TIME;
6044         ihold(inode);
6045         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6046
6047         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6048
6049         if (err) {
6050                 drop_inode = 1;
6051         } else {
6052                 struct dentry *parent = dentry->d_parent;
6053                 err = btrfs_update_inode(trans, root, inode);
6054                 if (err)
6055                         goto fail;
6056                 if (inode->i_nlink == 1) {
6057                         /*
6058                          * If new hard link count is 1, it's a file created
6059                          * with open(2) O_TMPFILE flag.
6060                          */
6061                         err = btrfs_orphan_del(trans, inode);
6062                         if (err)
6063                                 goto fail;
6064                 }
6065                 d_instantiate(dentry, inode);
6066                 btrfs_log_new_name(trans, inode, NULL, parent);
6067         }
6068
6069         btrfs_end_transaction(trans, root);
6070         btrfs_balance_delayed_items(root);
6071 fail:
6072         if (drop_inode) {
6073                 inode_dec_link_count(inode);
6074                 iput(inode);
6075         }
6076         btrfs_btree_balance_dirty(root);
6077         return err;
6078 }
6079
6080 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6081 {
6082         struct inode *inode = NULL;
6083         struct btrfs_trans_handle *trans;
6084         struct btrfs_root *root = BTRFS_I(dir)->root;
6085         int err = 0;
6086         int drop_on_err = 0;
6087         u64 objectid = 0;
6088         u64 index = 0;
6089
6090         /*
6091          * 2 items for inode and ref
6092          * 2 items for dir items
6093          * 1 for xattr if selinux is on
6094          */
6095         trans = btrfs_start_transaction(root, 5);
6096         if (IS_ERR(trans))
6097                 return PTR_ERR(trans);
6098
6099         err = btrfs_find_free_ino(root, &objectid);
6100         if (err)
6101                 goto out_fail;
6102
6103         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6104                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6105                                 S_IFDIR | mode, &index);
6106         if (IS_ERR(inode)) {
6107                 err = PTR_ERR(inode);
6108                 goto out_fail;
6109         }
6110
6111         drop_on_err = 1;
6112
6113         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6114         if (err)
6115                 goto out_fail;
6116
6117         inode->i_op = &btrfs_dir_inode_operations;
6118         inode->i_fop = &btrfs_dir_file_operations;
6119
6120         btrfs_i_size_write(inode, 0);
6121         err = btrfs_update_inode(trans, root, inode);
6122         if (err)
6123                 goto out_fail;
6124
6125         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6126                              dentry->d_name.len, 0, index);
6127         if (err)
6128                 goto out_fail;
6129
6130         d_instantiate(dentry, inode);
6131         drop_on_err = 0;
6132
6133 out_fail:
6134         btrfs_end_transaction(trans, root);
6135         if (drop_on_err)
6136                 iput(inode);
6137         btrfs_balance_delayed_items(root);
6138         btrfs_btree_balance_dirty(root);
6139         return err;
6140 }
6141
6142 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6143  * and an extent that you want to insert, deal with overlap and insert
6144  * the new extent into the tree.
6145  */
6146 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6147                                 struct extent_map *existing,
6148                                 struct extent_map *em,
6149                                 u64 map_start)
6150 {
6151         u64 start_diff;
6152
6153         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6154         start_diff = map_start - em->start;
6155         em->start = map_start;
6156         em->len = existing->start - em->start;
6157         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6158             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6159                 em->block_start += start_diff;
6160                 em->block_len -= start_diff;
6161         }
6162         return add_extent_mapping(em_tree, em, 0);
6163 }
6164
6165 static noinline int uncompress_inline(struct btrfs_path *path,
6166                                       struct inode *inode, struct page *page,
6167                                       size_t pg_offset, u64 extent_offset,
6168                                       struct btrfs_file_extent_item *item)
6169 {
6170         int ret;
6171         struct extent_buffer *leaf = path->nodes[0];
6172         char *tmp;
6173         size_t max_size;
6174         unsigned long inline_size;
6175         unsigned long ptr;
6176         int compress_type;
6177
6178         WARN_ON(pg_offset != 0);
6179         compress_type = btrfs_file_extent_compression(leaf, item);
6180         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6181         inline_size = btrfs_file_extent_inline_item_len(leaf,
6182                                         btrfs_item_nr(path->slots[0]));
6183         tmp = kmalloc(inline_size, GFP_NOFS);
6184         if (!tmp)
6185                 return -ENOMEM;
6186         ptr = btrfs_file_extent_inline_start(item);
6187
6188         read_extent_buffer(leaf, tmp, ptr, inline_size);
6189
6190         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6191         ret = btrfs_decompress(compress_type, tmp, page,
6192                                extent_offset, inline_size, max_size);
6193         kfree(tmp);
6194         return ret;
6195 }
6196
6197 /*
6198  * a bit scary, this does extent mapping from logical file offset to the disk.
6199  * the ugly parts come from merging extents from the disk with the in-ram
6200  * representation.  This gets more complex because of the data=ordered code,
6201  * where the in-ram extents might be locked pending data=ordered completion.
6202  *
6203  * This also copies inline extents directly into the page.
6204  */
6205
6206 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6207                                     size_t pg_offset, u64 start, u64 len,
6208                                     int create)
6209 {
6210         int ret;
6211         int err = 0;
6212         u64 extent_start = 0;
6213         u64 extent_end = 0;
6214         u64 objectid = btrfs_ino(inode);
6215         u32 found_type;
6216         struct btrfs_path *path = NULL;
6217         struct btrfs_root *root = BTRFS_I(inode)->root;
6218         struct btrfs_file_extent_item *item;
6219         struct extent_buffer *leaf;
6220         struct btrfs_key found_key;
6221         struct extent_map *em = NULL;
6222         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6223         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6224         struct btrfs_trans_handle *trans = NULL;
6225         const bool new_inline = !page || create;
6226
6227 again:
6228         read_lock(&em_tree->lock);
6229         em = lookup_extent_mapping(em_tree, start, len);
6230         if (em)
6231                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6232         read_unlock(&em_tree->lock);
6233
6234         if (em) {
6235                 if (em->start > start || em->start + em->len <= start)
6236                         free_extent_map(em);
6237                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6238                         free_extent_map(em);
6239                 else
6240                         goto out;
6241         }
6242         em = alloc_extent_map();
6243         if (!em) {
6244                 err = -ENOMEM;
6245                 goto out;
6246         }
6247         em->bdev = root->fs_info->fs_devices->latest_bdev;
6248         em->start = EXTENT_MAP_HOLE;
6249         em->orig_start = EXTENT_MAP_HOLE;
6250         em->len = (u64)-1;
6251         em->block_len = (u64)-1;
6252
6253         if (!path) {
6254                 path = btrfs_alloc_path();
6255                 if (!path) {
6256                         err = -ENOMEM;
6257                         goto out;
6258                 }
6259                 /*
6260                  * Chances are we'll be called again, so go ahead and do
6261                  * readahead
6262                  */
6263                 path->reada = 1;
6264         }
6265
6266         ret = btrfs_lookup_file_extent(trans, root, path,
6267                                        objectid, start, trans != NULL);
6268         if (ret < 0) {
6269                 err = ret;
6270                 goto out;
6271         }
6272
6273         if (ret != 0) {
6274                 if (path->slots[0] == 0)
6275                         goto not_found;
6276                 path->slots[0]--;
6277         }
6278
6279         leaf = path->nodes[0];
6280         item = btrfs_item_ptr(leaf, path->slots[0],
6281                               struct btrfs_file_extent_item);
6282         /* are we inside the extent that was found? */
6283         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6284         found_type = btrfs_key_type(&found_key);
6285         if (found_key.objectid != objectid ||
6286             found_type != BTRFS_EXTENT_DATA_KEY) {
6287                 /*
6288                  * If we backup past the first extent we want to move forward
6289                  * and see if there is an extent in front of us, otherwise we'll
6290                  * say there is a hole for our whole search range which can
6291                  * cause problems.
6292                  */
6293                 extent_end = start;
6294                 goto next;
6295         }
6296
6297         found_type = btrfs_file_extent_type(leaf, item);
6298         extent_start = found_key.offset;
6299         if (found_type == BTRFS_FILE_EXTENT_REG ||
6300             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6301                 extent_end = extent_start +
6302                        btrfs_file_extent_num_bytes(leaf, item);
6303         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6304                 size_t size;
6305                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6306                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6307         }
6308 next:
6309         if (start >= extent_end) {
6310                 path->slots[0]++;
6311                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6312                         ret = btrfs_next_leaf(root, path);
6313                         if (ret < 0) {
6314                                 err = ret;
6315                                 goto out;
6316                         }
6317                         if (ret > 0)
6318                                 goto not_found;
6319                         leaf = path->nodes[0];
6320                 }
6321                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6322                 if (found_key.objectid != objectid ||
6323                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6324                         goto not_found;
6325                 if (start + len <= found_key.offset)
6326                         goto not_found;
6327                 if (start > found_key.offset)
6328                         goto next;
6329                 em->start = start;
6330                 em->orig_start = start;
6331                 em->len = found_key.offset - start;
6332                 goto not_found_em;
6333         }
6334
6335         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6336
6337         if (found_type == BTRFS_FILE_EXTENT_REG ||
6338             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6339                 goto insert;
6340         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6341                 unsigned long ptr;
6342                 char *map;
6343                 size_t size;
6344                 size_t extent_offset;
6345                 size_t copy_size;
6346
6347                 if (new_inline)
6348                         goto out;
6349
6350                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6351                 extent_offset = page_offset(page) + pg_offset - extent_start;
6352                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6353                                 size - extent_offset);
6354                 em->start = extent_start + extent_offset;
6355                 em->len = ALIGN(copy_size, root->sectorsize);
6356                 em->orig_block_len = em->len;
6357                 em->orig_start = em->start;
6358                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6359                 if (create == 0 && !PageUptodate(page)) {
6360                         if (btrfs_file_extent_compression(leaf, item) !=
6361                             BTRFS_COMPRESS_NONE) {
6362                                 ret = uncompress_inline(path, inode, page,
6363                                                         pg_offset,
6364                                                         extent_offset, item);
6365                                 if (ret) {
6366                                         err = ret;
6367                                         goto out;
6368                                 }
6369                         } else {
6370                                 map = kmap(page);
6371                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6372                                                    copy_size);
6373                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6374                                         memset(map + pg_offset + copy_size, 0,
6375                                                PAGE_CACHE_SIZE - pg_offset -
6376                                                copy_size);
6377                                 }
6378                                 kunmap(page);
6379                         }
6380                         flush_dcache_page(page);
6381                 } else if (create && PageUptodate(page)) {
6382                         BUG();
6383                         if (!trans) {
6384                                 kunmap(page);
6385                                 free_extent_map(em);
6386                                 em = NULL;
6387
6388                                 btrfs_release_path(path);
6389                                 trans = btrfs_join_transaction(root);
6390
6391                                 if (IS_ERR(trans))
6392                                         return ERR_CAST(trans);
6393                                 goto again;
6394                         }
6395                         map = kmap(page);
6396                         write_extent_buffer(leaf, map + pg_offset, ptr,
6397                                             copy_size);
6398                         kunmap(page);
6399                         btrfs_mark_buffer_dirty(leaf);
6400                 }
6401                 set_extent_uptodate(io_tree, em->start,
6402                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6403                 goto insert;
6404         }
6405 not_found:
6406         em->start = start;
6407         em->orig_start = start;
6408         em->len = len;
6409 not_found_em:
6410         em->block_start = EXTENT_MAP_HOLE;
6411         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6412 insert:
6413         btrfs_release_path(path);
6414         if (em->start > start || extent_map_end(em) <= start) {
6415                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6416                         em->start, em->len, start, len);
6417                 err = -EIO;
6418                 goto out;
6419         }
6420
6421         err = 0;
6422         write_lock(&em_tree->lock);
6423         ret = add_extent_mapping(em_tree, em, 0);
6424         /* it is possible that someone inserted the extent into the tree
6425          * while we had the lock dropped.  It is also possible that
6426          * an overlapping map exists in the tree
6427          */
6428         if (ret == -EEXIST) {
6429                 struct extent_map *existing;
6430
6431                 ret = 0;
6432
6433                 existing = lookup_extent_mapping(em_tree, start, len);
6434                 if (existing && (existing->start > start ||
6435                     existing->start + existing->len <= start)) {
6436                         free_extent_map(existing);
6437                         existing = NULL;
6438                 }
6439                 if (!existing) {
6440                         existing = lookup_extent_mapping(em_tree, em->start,
6441                                                          em->len);
6442                         if (existing) {
6443                                 err = merge_extent_mapping(em_tree, existing,
6444                                                            em, start);
6445                                 free_extent_map(existing);
6446                                 if (err) {
6447                                         free_extent_map(em);
6448                                         em = NULL;
6449                                 }
6450                         } else {
6451                                 err = -EIO;
6452                                 free_extent_map(em);
6453                                 em = NULL;
6454                         }
6455                 } else {
6456                         free_extent_map(em);
6457                         em = existing;
6458                         err = 0;
6459                 }
6460         }
6461         write_unlock(&em_tree->lock);
6462 out:
6463
6464         trace_btrfs_get_extent(root, em);
6465
6466         if (path)
6467                 btrfs_free_path(path);
6468         if (trans) {
6469                 ret = btrfs_end_transaction(trans, root);
6470                 if (!err)
6471                         err = ret;
6472         }
6473         if (err) {
6474                 free_extent_map(em);
6475                 return ERR_PTR(err);
6476         }
6477         BUG_ON(!em); /* Error is always set */
6478         return em;
6479 }
6480
6481 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6482                                            size_t pg_offset, u64 start, u64 len,
6483                                            int create)
6484 {
6485         struct extent_map *em;
6486         struct extent_map *hole_em = NULL;
6487         u64 range_start = start;
6488         u64 end;
6489         u64 found;
6490         u64 found_end;
6491         int err = 0;
6492
6493         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6494         if (IS_ERR(em))
6495                 return em;
6496         if (em) {
6497                 /*
6498                  * if our em maps to
6499                  * -  a hole or
6500                  * -  a pre-alloc extent,
6501                  * there might actually be delalloc bytes behind it.
6502                  */
6503                 if (em->block_start != EXTENT_MAP_HOLE &&
6504                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6505                         return em;
6506                 else
6507                         hole_em = em;
6508         }
6509
6510         /* check to see if we've wrapped (len == -1 or similar) */
6511         end = start + len;
6512         if (end < start)
6513                 end = (u64)-1;
6514         else
6515                 end -= 1;
6516
6517         em = NULL;
6518
6519         /* ok, we didn't find anything, lets look for delalloc */
6520         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6521                                  end, len, EXTENT_DELALLOC, 1);
6522         found_end = range_start + found;
6523         if (found_end < range_start)
6524                 found_end = (u64)-1;
6525
6526         /*
6527          * we didn't find anything useful, return
6528          * the original results from get_extent()
6529          */
6530         if (range_start > end || found_end <= start) {
6531                 em = hole_em;
6532                 hole_em = NULL;
6533                 goto out;
6534         }
6535
6536         /* adjust the range_start to make sure it doesn't
6537          * go backwards from the start they passed in
6538          */
6539         range_start = max(start, range_start);
6540         found = found_end - range_start;
6541
6542         if (found > 0) {
6543                 u64 hole_start = start;
6544                 u64 hole_len = len;
6545
6546                 em = alloc_extent_map();
6547                 if (!em) {
6548                         err = -ENOMEM;
6549                         goto out;
6550                 }
6551                 /*
6552                  * when btrfs_get_extent can't find anything it
6553                  * returns one huge hole
6554                  *
6555                  * make sure what it found really fits our range, and
6556                  * adjust to make sure it is based on the start from
6557                  * the caller
6558                  */
6559                 if (hole_em) {
6560                         u64 calc_end = extent_map_end(hole_em);
6561
6562                         if (calc_end <= start || (hole_em->start > end)) {
6563                                 free_extent_map(hole_em);
6564                                 hole_em = NULL;
6565                         } else {
6566                                 hole_start = max(hole_em->start, start);
6567                                 hole_len = calc_end - hole_start;
6568                         }
6569                 }
6570                 em->bdev = NULL;
6571                 if (hole_em && range_start > hole_start) {
6572                         /* our hole starts before our delalloc, so we
6573                          * have to return just the parts of the hole
6574                          * that go until  the delalloc starts
6575                          */
6576                         em->len = min(hole_len,
6577                                       range_start - hole_start);
6578                         em->start = hole_start;
6579                         em->orig_start = hole_start;
6580                         /*
6581                          * don't adjust block start at all,
6582                          * it is fixed at EXTENT_MAP_HOLE
6583                          */
6584                         em->block_start = hole_em->block_start;
6585                         em->block_len = hole_len;
6586                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6587                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6588                 } else {
6589                         em->start = range_start;
6590                         em->len = found;
6591                         em->orig_start = range_start;
6592                         em->block_start = EXTENT_MAP_DELALLOC;
6593                         em->block_len = found;
6594                 }
6595         } else if (hole_em) {
6596                 return hole_em;
6597         }
6598 out:
6599
6600         free_extent_map(hole_em);
6601         if (err) {
6602                 free_extent_map(em);
6603                 return ERR_PTR(err);
6604         }
6605         return em;
6606 }
6607
6608 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6609                                                   u64 start, u64 len)
6610 {
6611         struct btrfs_root *root = BTRFS_I(inode)->root;
6612         struct extent_map *em;
6613         struct btrfs_key ins;
6614         u64 alloc_hint;
6615         int ret;
6616
6617         alloc_hint = get_extent_allocation_hint(inode, start, len);
6618         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6619                                    alloc_hint, &ins, 1, 1);
6620         if (ret)
6621                 return ERR_PTR(ret);
6622
6623         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6624                               ins.offset, ins.offset, ins.offset, 0);
6625         if (IS_ERR(em)) {
6626                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6627                 return em;
6628         }
6629
6630         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6631                                            ins.offset, ins.offset, 0);
6632         if (ret) {
6633                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6634                 free_extent_map(em);
6635                 return ERR_PTR(ret);
6636         }
6637
6638         return em;
6639 }
6640
6641 /*
6642  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6643  * block must be cow'd
6644  */
6645 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6646                               u64 *orig_start, u64 *orig_block_len,
6647                               u64 *ram_bytes)
6648 {
6649         struct btrfs_trans_handle *trans;
6650         struct btrfs_path *path;
6651         int ret;
6652         struct extent_buffer *leaf;
6653         struct btrfs_root *root = BTRFS_I(inode)->root;
6654         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6655         struct btrfs_file_extent_item *fi;
6656         struct btrfs_key key;
6657         u64 disk_bytenr;
6658         u64 backref_offset;
6659         u64 extent_end;
6660         u64 num_bytes;
6661         int slot;
6662         int found_type;
6663         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6664
6665         path = btrfs_alloc_path();
6666         if (!path)
6667                 return -ENOMEM;
6668
6669         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6670                                        offset, 0);
6671         if (ret < 0)
6672                 goto out;
6673
6674         slot = path->slots[0];
6675         if (ret == 1) {
6676                 if (slot == 0) {
6677                         /* can't find the item, must cow */
6678                         ret = 0;
6679                         goto out;
6680                 }
6681                 slot--;
6682         }
6683         ret = 0;
6684         leaf = path->nodes[0];
6685         btrfs_item_key_to_cpu(leaf, &key, slot);
6686         if (key.objectid != btrfs_ino(inode) ||
6687             key.type != BTRFS_EXTENT_DATA_KEY) {
6688                 /* not our file or wrong item type, must cow */
6689                 goto out;
6690         }
6691
6692         if (key.offset > offset) {
6693                 /* Wrong offset, must cow */
6694                 goto out;
6695         }
6696
6697         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6698         found_type = btrfs_file_extent_type(leaf, fi);
6699         if (found_type != BTRFS_FILE_EXTENT_REG &&
6700             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6701                 /* not a regular extent, must cow */
6702                 goto out;
6703         }
6704
6705         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6706                 goto out;
6707
6708         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6709         if (extent_end <= offset)
6710                 goto out;
6711
6712         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6713         if (disk_bytenr == 0)
6714                 goto out;
6715
6716         if (btrfs_file_extent_compression(leaf, fi) ||
6717             btrfs_file_extent_encryption(leaf, fi) ||
6718             btrfs_file_extent_other_encoding(leaf, fi))
6719                 goto out;
6720
6721         backref_offset = btrfs_file_extent_offset(leaf, fi);
6722
6723         if (orig_start) {
6724                 *orig_start = key.offset - backref_offset;
6725                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6726                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6727         }
6728
6729         if (btrfs_extent_readonly(root, disk_bytenr))
6730                 goto out;
6731
6732         num_bytes = min(offset + *len, extent_end) - offset;
6733         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6734                 u64 range_end;
6735
6736                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
6737                 ret = test_range_bit(io_tree, offset, range_end,
6738                                      EXTENT_DELALLOC, 0, NULL);
6739                 if (ret) {
6740                         ret = -EAGAIN;
6741                         goto out;
6742                 }
6743         }
6744
6745         btrfs_release_path(path);
6746
6747         /*
6748          * look for other files referencing this extent, if we
6749          * find any we must cow
6750          */
6751         trans = btrfs_join_transaction(root);
6752         if (IS_ERR(trans)) {
6753                 ret = 0;
6754                 goto out;
6755         }
6756
6757         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6758                                     key.offset - backref_offset, disk_bytenr);
6759         btrfs_end_transaction(trans, root);
6760         if (ret) {
6761                 ret = 0;
6762                 goto out;
6763         }
6764
6765         /*
6766          * adjust disk_bytenr and num_bytes to cover just the bytes
6767          * in this extent we are about to write.  If there
6768          * are any csums in that range we have to cow in order
6769          * to keep the csums correct
6770          */
6771         disk_bytenr += backref_offset;
6772         disk_bytenr += offset - key.offset;
6773         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6774                                 goto out;
6775         /*
6776          * all of the above have passed, it is safe to overwrite this extent
6777          * without cow
6778          */
6779         *len = num_bytes;
6780         ret = 1;
6781 out:
6782         btrfs_free_path(path);
6783         return ret;
6784 }
6785
6786 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
6787 {
6788         struct radix_tree_root *root = &inode->i_mapping->page_tree;
6789         int found = false;
6790         void **pagep = NULL;
6791         struct page *page = NULL;
6792         int start_idx;
6793         int end_idx;
6794
6795         start_idx = start >> PAGE_CACHE_SHIFT;
6796
6797         /*
6798          * end is the last byte in the last page.  end == start is legal
6799          */
6800         end_idx = end >> PAGE_CACHE_SHIFT;
6801
6802         rcu_read_lock();
6803
6804         /* Most of the code in this while loop is lifted from
6805          * find_get_page.  It's been modified to begin searching from a
6806          * page and return just the first page found in that range.  If the
6807          * found idx is less than or equal to the end idx then we know that
6808          * a page exists.  If no pages are found or if those pages are
6809          * outside of the range then we're fine (yay!) */
6810         while (page == NULL &&
6811                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
6812                 page = radix_tree_deref_slot(pagep);
6813                 if (unlikely(!page))
6814                         break;
6815
6816                 if (radix_tree_exception(page)) {
6817                         if (radix_tree_deref_retry(page)) {
6818                                 page = NULL;
6819                                 continue;
6820                         }
6821                         /*
6822                          * Otherwise, shmem/tmpfs must be storing a swap entry
6823                          * here as an exceptional entry: so return it without
6824                          * attempting to raise page count.
6825                          */
6826                         page = NULL;
6827                         break; /* TODO: Is this relevant for this use case? */
6828                 }
6829
6830                 if (!page_cache_get_speculative(page)) {
6831                         page = NULL;
6832                         continue;
6833                 }
6834
6835                 /*
6836                  * Has the page moved?
6837                  * This is part of the lockless pagecache protocol. See
6838                  * include/linux/pagemap.h for details.
6839                  */
6840                 if (unlikely(page != *pagep)) {
6841                         page_cache_release(page);
6842                         page = NULL;
6843                 }
6844         }
6845
6846         if (page) {
6847                 if (page->index <= end_idx)
6848                         found = true;
6849                 page_cache_release(page);
6850         }
6851
6852         rcu_read_unlock();
6853         return found;
6854 }
6855
6856 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6857                               struct extent_state **cached_state, int writing)
6858 {
6859         struct btrfs_ordered_extent *ordered;
6860         int ret = 0;
6861
6862         while (1) {
6863                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6864                                  0, cached_state);
6865                 /*
6866                  * We're concerned with the entire range that we're going to be
6867                  * doing DIO to, so we need to make sure theres no ordered
6868                  * extents in this range.
6869                  */
6870                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6871                                                      lockend - lockstart + 1);
6872
6873                 /*
6874                  * We need to make sure there are no buffered pages in this
6875                  * range either, we could have raced between the invalidate in
6876                  * generic_file_direct_write and locking the extent.  The
6877                  * invalidate needs to happen so that reads after a write do not
6878                  * get stale data.
6879                  */
6880                 if (!ordered &&
6881                     (!writing ||
6882                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
6883                         break;
6884
6885                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6886                                      cached_state, GFP_NOFS);
6887
6888                 if (ordered) {
6889                         btrfs_start_ordered_extent(inode, ordered, 1);
6890                         btrfs_put_ordered_extent(ordered);
6891                 } else {
6892                         /* Screw you mmap */
6893                         ret = filemap_write_and_wait_range(inode->i_mapping,
6894                                                            lockstart,
6895                                                            lockend);
6896                         if (ret)
6897                                 break;
6898
6899                         /*
6900                          * If we found a page that couldn't be invalidated just
6901                          * fall back to buffered.
6902                          */
6903                         ret = invalidate_inode_pages2_range(inode->i_mapping,
6904                                         lockstart >> PAGE_CACHE_SHIFT,
6905                                         lockend >> PAGE_CACHE_SHIFT);
6906                         if (ret)
6907                                 break;
6908                 }
6909
6910                 cond_resched();
6911         }
6912
6913         return ret;
6914 }
6915
6916 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
6917                                            u64 len, u64 orig_start,
6918                                            u64 block_start, u64 block_len,
6919                                            u64 orig_block_len, u64 ram_bytes,
6920                                            int type)
6921 {
6922         struct extent_map_tree *em_tree;
6923         struct extent_map *em;
6924         struct btrfs_root *root = BTRFS_I(inode)->root;
6925         int ret;
6926
6927         em_tree = &BTRFS_I(inode)->extent_tree;
6928         em = alloc_extent_map();
6929         if (!em)
6930                 return ERR_PTR(-ENOMEM);
6931
6932         em->start = start;
6933         em->orig_start = orig_start;
6934         em->mod_start = start;
6935         em->mod_len = len;
6936         em->len = len;
6937         em->block_len = block_len;
6938         em->block_start = block_start;
6939         em->bdev = root->fs_info->fs_devices->latest_bdev;
6940         em->orig_block_len = orig_block_len;
6941         em->ram_bytes = ram_bytes;
6942         em->generation = -1;
6943         set_bit(EXTENT_FLAG_PINNED, &em->flags);
6944         if (type == BTRFS_ORDERED_PREALLOC)
6945                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
6946
6947         do {
6948                 btrfs_drop_extent_cache(inode, em->start,
6949                                 em->start + em->len - 1, 0);
6950                 write_lock(&em_tree->lock);
6951                 ret = add_extent_mapping(em_tree, em, 1);
6952                 write_unlock(&em_tree->lock);
6953         } while (ret == -EEXIST);
6954
6955         if (ret) {
6956                 free_extent_map(em);
6957                 return ERR_PTR(ret);
6958         }
6959
6960         return em;
6961 }
6962
6963
6964 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
6965                                    struct buffer_head *bh_result, int create)
6966 {
6967         struct extent_map *em;
6968         struct btrfs_root *root = BTRFS_I(inode)->root;
6969         struct extent_state *cached_state = NULL;
6970         u64 start = iblock << inode->i_blkbits;
6971         u64 lockstart, lockend;
6972         u64 len = bh_result->b_size;
6973         int unlock_bits = EXTENT_LOCKED;
6974         int ret = 0;
6975
6976         if (create)
6977                 unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
6978         else
6979                 len = min_t(u64, len, root->sectorsize);
6980
6981         lockstart = start;
6982         lockend = start + len - 1;
6983
6984         /*
6985          * If this errors out it's because we couldn't invalidate pagecache for
6986          * this range and we need to fallback to buffered.
6987          */
6988         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
6989                 return -ENOTBLK;
6990
6991         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
6992         if (IS_ERR(em)) {
6993                 ret = PTR_ERR(em);
6994                 goto unlock_err;
6995         }
6996
6997         /*
6998          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
6999          * io.  INLINE is special, and we could probably kludge it in here, but
7000          * it's still buffered so for safety lets just fall back to the generic
7001          * buffered path.
7002          *
7003          * For COMPRESSED we _have_ to read the entire extent in so we can
7004          * decompress it, so there will be buffering required no matter what we
7005          * do, so go ahead and fallback to buffered.
7006          *
7007          * We return -ENOTBLK because thats what makes DIO go ahead and go back
7008          * to buffered IO.  Don't blame me, this is the price we pay for using
7009          * the generic code.
7010          */
7011         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7012             em->block_start == EXTENT_MAP_INLINE) {
7013                 free_extent_map(em);
7014                 ret = -ENOTBLK;
7015                 goto unlock_err;
7016         }
7017
7018         /* Just a good old fashioned hole, return */
7019         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7020                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7021                 free_extent_map(em);
7022                 goto unlock_err;
7023         }
7024
7025         /*
7026          * We don't allocate a new extent in the following cases
7027          *
7028          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7029          * existing extent.
7030          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7031          * just use the extent.
7032          *
7033          */
7034         if (!create) {
7035                 len = min(len, em->len - (start - em->start));
7036                 lockstart = start + len;
7037                 goto unlock;
7038         }
7039
7040         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7041             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7042              em->block_start != EXTENT_MAP_HOLE)) {
7043                 int type;
7044                 int ret;
7045                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7046
7047                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7048                         type = BTRFS_ORDERED_PREALLOC;
7049                 else
7050                         type = BTRFS_ORDERED_NOCOW;
7051                 len = min(len, em->len - (start - em->start));
7052                 block_start = em->block_start + (start - em->start);
7053
7054                 if (can_nocow_extent(inode, start, &len, &orig_start,
7055                                      &orig_block_len, &ram_bytes) == 1) {
7056                         if (type == BTRFS_ORDERED_PREALLOC) {
7057                                 free_extent_map(em);
7058                                 em = create_pinned_em(inode, start, len,
7059                                                        orig_start,
7060                                                        block_start, len,
7061                                                        orig_block_len,
7062                                                        ram_bytes, type);
7063                                 if (IS_ERR(em))
7064                                         goto unlock_err;
7065                         }
7066
7067                         ret = btrfs_add_ordered_extent_dio(inode, start,
7068                                            block_start, len, len, type);
7069                         if (ret) {
7070                                 free_extent_map(em);
7071                                 goto unlock_err;
7072                         }
7073                         goto unlock;
7074                 }
7075         }
7076
7077         /*
7078          * this will cow the extent, reset the len in case we changed
7079          * it above
7080          */
7081         len = bh_result->b_size;
7082         free_extent_map(em);
7083         em = btrfs_new_extent_direct(inode, start, len);
7084         if (IS_ERR(em)) {
7085                 ret = PTR_ERR(em);
7086                 goto unlock_err;
7087         }
7088         len = min(len, em->len - (start - em->start));
7089 unlock:
7090         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7091                 inode->i_blkbits;
7092         bh_result->b_size = len;
7093         bh_result->b_bdev = em->bdev;
7094         set_buffer_mapped(bh_result);
7095         if (create) {
7096                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7097                         set_buffer_new(bh_result);
7098
7099                 /*
7100                  * Need to update the i_size under the extent lock so buffered
7101                  * readers will get the updated i_size when we unlock.
7102                  */
7103                 if (start + len > i_size_read(inode))
7104                         i_size_write(inode, start + len);
7105
7106                 spin_lock(&BTRFS_I(inode)->lock);
7107                 BTRFS_I(inode)->outstanding_extents++;
7108                 spin_unlock(&BTRFS_I(inode)->lock);
7109
7110                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7111                                      lockstart + len - 1, EXTENT_DELALLOC, NULL,
7112                                      &cached_state, GFP_NOFS);
7113                 BUG_ON(ret);
7114         }
7115
7116         /*
7117          * In the case of write we need to clear and unlock the entire range,
7118          * in the case of read we need to unlock only the end area that we
7119          * aren't using if there is any left over space.
7120          */
7121         if (lockstart < lockend) {
7122                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7123                                  lockend, unlock_bits, 1, 0,
7124                                  &cached_state, GFP_NOFS);
7125         } else {
7126                 free_extent_state(cached_state);
7127         }
7128
7129         free_extent_map(em);
7130
7131         return 0;
7132
7133 unlock_err:
7134         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7135                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7136         return ret;
7137 }
7138
7139 static void btrfs_endio_direct_read(struct bio *bio, int err)
7140 {
7141         struct btrfs_dio_private *dip = bio->bi_private;
7142         struct bio_vec *bvec;
7143         struct inode *inode = dip->inode;
7144         struct btrfs_root *root = BTRFS_I(inode)->root;
7145         struct bio *dio_bio;
7146         u32 *csums = (u32 *)dip->csum;
7147         u64 start;
7148         int i;
7149
7150         start = dip->logical_offset;
7151         bio_for_each_segment_all(bvec, bio, i) {
7152                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
7153                         struct page *page = bvec->bv_page;
7154                         char *kaddr;
7155                         u32 csum = ~(u32)0;
7156                         unsigned long flags;
7157
7158                         local_irq_save(flags);
7159                         kaddr = kmap_atomic(page);
7160                         csum = btrfs_csum_data(kaddr + bvec->bv_offset,
7161                                                csum, bvec->bv_len);
7162                         btrfs_csum_final(csum, (char *)&csum);
7163                         kunmap_atomic(kaddr);
7164                         local_irq_restore(flags);
7165
7166                         flush_dcache_page(bvec->bv_page);
7167                         if (csum != csums[i]) {
7168                                 btrfs_err(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
7169                                           btrfs_ino(inode), start, csum,
7170                                           csums[i]);
7171                                 err = -EIO;
7172                         }
7173                 }
7174
7175                 start += bvec->bv_len;
7176         }
7177
7178         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7179                       dip->logical_offset + dip->bytes - 1);
7180         dio_bio = dip->dio_bio;
7181
7182         kfree(dip);
7183
7184         /* If we had a csum failure make sure to clear the uptodate flag */
7185         if (err)
7186                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7187         dio_end_io(dio_bio, err);
7188         bio_put(bio);
7189 }
7190
7191 static void btrfs_endio_direct_write(struct bio *bio, int err)
7192 {
7193         struct btrfs_dio_private *dip = bio->bi_private;
7194         struct inode *inode = dip->inode;
7195         struct btrfs_root *root = BTRFS_I(inode)->root;
7196         struct btrfs_ordered_extent *ordered = NULL;
7197         u64 ordered_offset = dip->logical_offset;
7198         u64 ordered_bytes = dip->bytes;
7199         struct bio *dio_bio;
7200         int ret;
7201
7202         if (err)
7203                 goto out_done;
7204 again:
7205         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
7206                                                    &ordered_offset,
7207                                                    ordered_bytes, !err);
7208         if (!ret)
7209                 goto out_test;
7210
7211         btrfs_init_work(&ordered->work, finish_ordered_fn, NULL, NULL);
7212         btrfs_queue_work(root->fs_info->endio_write_workers,
7213                          &ordered->work);
7214 out_test:
7215         /*
7216          * our bio might span multiple ordered extents.  If we haven't
7217          * completed the accounting for the whole dio, go back and try again
7218          */
7219         if (ordered_offset < dip->logical_offset + dip->bytes) {
7220                 ordered_bytes = dip->logical_offset + dip->bytes -
7221                         ordered_offset;
7222                 ordered = NULL;
7223                 goto again;
7224         }
7225 out_done:
7226         dio_bio = dip->dio_bio;
7227
7228         kfree(dip);
7229
7230         /* If we had an error make sure to clear the uptodate flag */
7231         if (err)
7232                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7233         dio_end_io(dio_bio, err);
7234         bio_put(bio);
7235 }
7236
7237 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7238                                     struct bio *bio, int mirror_num,
7239                                     unsigned long bio_flags, u64 offset)
7240 {
7241         int ret;
7242         struct btrfs_root *root = BTRFS_I(inode)->root;
7243         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7244         BUG_ON(ret); /* -ENOMEM */
7245         return 0;
7246 }
7247
7248 static void btrfs_end_dio_bio(struct bio *bio, int err)
7249 {
7250         struct btrfs_dio_private *dip = bio->bi_private;
7251
7252         if (err) {
7253                 btrfs_err(BTRFS_I(dip->inode)->root->fs_info,
7254                           "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7255                       btrfs_ino(dip->inode), bio->bi_rw,
7256                       (unsigned long long)bio->bi_iter.bi_sector,
7257                       bio->bi_iter.bi_size, err);
7258                 dip->errors = 1;
7259
7260                 /*
7261                  * before atomic variable goto zero, we must make sure
7262                  * dip->errors is perceived to be set.
7263                  */
7264                 smp_mb__before_atomic();
7265         }
7266
7267         /* if there are more bios still pending for this dio, just exit */
7268         if (!atomic_dec_and_test(&dip->pending_bios))
7269                 goto out;
7270
7271         if (dip->errors) {
7272                 bio_io_error(dip->orig_bio);
7273         } else {
7274                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7275                 bio_endio(dip->orig_bio, 0);
7276         }
7277 out:
7278         bio_put(bio);
7279 }
7280
7281 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7282                                        u64 first_sector, gfp_t gfp_flags)
7283 {
7284         int nr_vecs = bio_get_nr_vecs(bdev);
7285         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7286 }
7287
7288 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7289                                          int rw, u64 file_offset, int skip_sum,
7290                                          int async_submit)
7291 {
7292         struct btrfs_dio_private *dip = bio->bi_private;
7293         int write = rw & REQ_WRITE;
7294         struct btrfs_root *root = BTRFS_I(inode)->root;
7295         int ret;
7296
7297         if (async_submit)
7298                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7299
7300         bio_get(bio);
7301
7302         if (!write) {
7303                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
7304                 if (ret)
7305                         goto err;
7306         }
7307
7308         if (skip_sum)
7309                 goto map;
7310
7311         if (write && async_submit) {
7312                 ret = btrfs_wq_submit_bio(root->fs_info,
7313                                    inode, rw, bio, 0, 0,
7314                                    file_offset,
7315                                    __btrfs_submit_bio_start_direct_io,
7316                                    __btrfs_submit_bio_done);
7317                 goto err;
7318         } else if (write) {
7319                 /*
7320                  * If we aren't doing async submit, calculate the csum of the
7321                  * bio now.
7322                  */
7323                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7324                 if (ret)
7325                         goto err;
7326         } else if (!skip_sum) {
7327                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip, bio,
7328                                                 file_offset);
7329                 if (ret)
7330                         goto err;
7331         }
7332
7333 map:
7334         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7335 err:
7336         bio_put(bio);
7337         return ret;
7338 }
7339
7340 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7341                                     int skip_sum)
7342 {
7343         struct inode *inode = dip->inode;
7344         struct btrfs_root *root = BTRFS_I(inode)->root;
7345         struct bio *bio;
7346         struct bio *orig_bio = dip->orig_bio;
7347         struct bio_vec *bvec = orig_bio->bi_io_vec;
7348         u64 start_sector = orig_bio->bi_iter.bi_sector;
7349         u64 file_offset = dip->logical_offset;
7350         u64 submit_len = 0;
7351         u64 map_length;
7352         int nr_pages = 0;
7353         int ret = 0;
7354         int async_submit = 0;
7355
7356         map_length = orig_bio->bi_iter.bi_size;
7357         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7358                               &map_length, NULL, 0);
7359         if (ret)
7360                 return -EIO;
7361
7362         if (map_length >= orig_bio->bi_iter.bi_size) {
7363                 bio = orig_bio;
7364                 goto submit;
7365         }
7366
7367         /* async crcs make it difficult to collect full stripe writes. */
7368         if (btrfs_get_alloc_profile(root, 1) &
7369             (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
7370                 async_submit = 0;
7371         else
7372                 async_submit = 1;
7373
7374         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7375         if (!bio)
7376                 return -ENOMEM;
7377
7378         bio->bi_private = dip;
7379         bio->bi_end_io = btrfs_end_dio_bio;
7380         atomic_inc(&dip->pending_bios);
7381
7382         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7383                 if (unlikely(map_length < submit_len + bvec->bv_len ||
7384                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7385                                  bvec->bv_offset) < bvec->bv_len)) {
7386                         /*
7387                          * inc the count before we submit the bio so
7388                          * we know the end IO handler won't happen before
7389                          * we inc the count. Otherwise, the dip might get freed
7390                          * before we're done setting it up
7391                          */
7392                         atomic_inc(&dip->pending_bios);
7393                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7394                                                      file_offset, skip_sum,
7395                                                      async_submit);
7396                         if (ret) {
7397                                 bio_put(bio);
7398                                 atomic_dec(&dip->pending_bios);
7399                                 goto out_err;
7400                         }
7401
7402                         start_sector += submit_len >> 9;
7403                         file_offset += submit_len;
7404
7405                         submit_len = 0;
7406                         nr_pages = 0;
7407
7408                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7409                                                   start_sector, GFP_NOFS);
7410                         if (!bio)
7411                                 goto out_err;
7412                         bio->bi_private = dip;
7413                         bio->bi_end_io = btrfs_end_dio_bio;
7414
7415                         map_length = orig_bio->bi_iter.bi_size;
7416                         ret = btrfs_map_block(root->fs_info, rw,
7417                                               start_sector << 9,
7418                                               &map_length, NULL, 0);
7419                         if (ret) {
7420                                 bio_put(bio);
7421                                 goto out_err;
7422                         }
7423                 } else {
7424                         submit_len += bvec->bv_len;
7425                         nr_pages++;
7426                         bvec++;
7427                 }
7428         }
7429
7430 submit:
7431         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7432                                      async_submit);
7433         if (!ret)
7434                 return 0;
7435
7436         bio_put(bio);
7437 out_err:
7438         dip->errors = 1;
7439         /*
7440          * before atomic variable goto zero, we must
7441          * make sure dip->errors is perceived to be set.
7442          */
7443         smp_mb__before_atomic();
7444         if (atomic_dec_and_test(&dip->pending_bios))
7445                 bio_io_error(dip->orig_bio);
7446
7447         /* bio_end_io() will handle error, so we needn't return it */
7448         return 0;
7449 }
7450
7451 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7452                                 struct inode *inode, loff_t file_offset)
7453 {
7454         struct btrfs_root *root = BTRFS_I(inode)->root;
7455         struct btrfs_dio_private *dip;
7456         struct bio *io_bio;
7457         int skip_sum;
7458         int sum_len;
7459         int write = rw & REQ_WRITE;
7460         int ret = 0;
7461         u16 csum_size;
7462
7463         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7464
7465         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7466         if (!io_bio) {
7467                 ret = -ENOMEM;
7468                 goto free_ordered;
7469         }
7470
7471         if (!skip_sum && !write) {
7472                 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
7473                 sum_len = dio_bio->bi_iter.bi_size >>
7474                         inode->i_sb->s_blocksize_bits;
7475                 sum_len *= csum_size;
7476         } else {
7477                 sum_len = 0;
7478         }
7479
7480         dip = kmalloc(sizeof(*dip) + sum_len, GFP_NOFS);
7481         if (!dip) {
7482                 ret = -ENOMEM;
7483                 goto free_io_bio;
7484         }
7485
7486         dip->private = dio_bio->bi_private;
7487         dip->inode = inode;
7488         dip->logical_offset = file_offset;
7489         dip->bytes = dio_bio->bi_iter.bi_size;
7490         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
7491         io_bio->bi_private = dip;
7492         dip->errors = 0;
7493         dip->orig_bio = io_bio;
7494         dip->dio_bio = dio_bio;
7495         atomic_set(&dip->pending_bios, 0);
7496
7497         if (write)
7498                 io_bio->bi_end_io = btrfs_endio_direct_write;
7499         else
7500                 io_bio->bi_end_io = btrfs_endio_direct_read;
7501
7502         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7503         if (!ret)
7504                 return;
7505
7506 free_io_bio:
7507         bio_put(io_bio);
7508
7509 free_ordered:
7510         /*
7511          * If this is a write, we need to clean up the reserved space and kill
7512          * the ordered extent.
7513          */
7514         if (write) {
7515                 struct btrfs_ordered_extent *ordered;
7516                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7517                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7518                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7519                         btrfs_free_reserved_extent(root, ordered->start,
7520                                                    ordered->disk_len, 1);
7521                 btrfs_put_ordered_extent(ordered);
7522                 btrfs_put_ordered_extent(ordered);
7523         }
7524         bio_endio(dio_bio, ret);
7525 }
7526
7527 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7528                         const struct iov_iter *iter, loff_t offset)
7529 {
7530         int seg;
7531         int i;
7532         unsigned blocksize_mask = root->sectorsize - 1;
7533         ssize_t retval = -EINVAL;
7534
7535         if (offset & blocksize_mask)
7536                 goto out;
7537
7538         if (iov_iter_alignment(iter) & blocksize_mask)
7539                 goto out;
7540
7541         /* If this is a write we don't need to check anymore */
7542         if (rw & WRITE)
7543                 return 0;
7544         /*
7545          * Check to make sure we don't have duplicate iov_base's in this
7546          * iovec, if so return EINVAL, otherwise we'll get csum errors
7547          * when reading back.
7548          */
7549         for (seg = 0; seg < iter->nr_segs; seg++) {
7550                 for (i = seg + 1; i < iter->nr_segs; i++) {
7551                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
7552                                 goto out;
7553                 }
7554         }
7555         retval = 0;
7556 out:
7557         return retval;
7558 }
7559
7560 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
7561                         struct iov_iter *iter, loff_t offset)
7562 {
7563         struct file *file = iocb->ki_filp;
7564         struct inode *inode = file->f_mapping->host;
7565         size_t count = 0;
7566         int flags = 0;
7567         bool wakeup = true;
7568         bool relock = false;
7569         ssize_t ret;
7570
7571         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iter, offset))
7572                 return 0;
7573
7574         atomic_inc(&inode->i_dio_count);
7575         smp_mb__after_atomic();
7576
7577         /*
7578          * The generic stuff only does filemap_write_and_wait_range, which
7579          * isn't enough if we've written compressed pages to this area, so
7580          * we need to flush the dirty pages again to make absolutely sure
7581          * that any outstanding dirty pages are on disk.
7582          */
7583         count = iov_iter_count(iter);
7584         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
7585                      &BTRFS_I(inode)->runtime_flags))
7586                 filemap_fdatawrite_range(inode->i_mapping, offset,
7587                                          offset + count - 1);
7588
7589         if (rw & WRITE) {
7590                 /*
7591                  * If the write DIO is beyond the EOF, we need update
7592                  * the isize, but it is protected by i_mutex. So we can
7593                  * not unlock the i_mutex at this case.
7594                  */
7595                 if (offset + count <= inode->i_size) {
7596                         mutex_unlock(&inode->i_mutex);
7597                         relock = true;
7598                 }
7599                 ret = btrfs_delalloc_reserve_space(inode, count);
7600                 if (ret)
7601                         goto out;
7602         } else if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
7603                                      &BTRFS_I(inode)->runtime_flags))) {
7604                 inode_dio_done(inode);
7605                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
7606                 wakeup = false;
7607         }
7608
7609         ret = __blockdev_direct_IO(rw, iocb, inode,
7610                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
7611                         iter, offset, btrfs_get_blocks_direct, NULL,
7612                         btrfs_submit_direct, flags);
7613         if (rw & WRITE) {
7614                 if (ret < 0 && ret != -EIOCBQUEUED)
7615                         btrfs_delalloc_release_space(inode, count);
7616                 else if (ret >= 0 && (size_t)ret < count)
7617                         btrfs_delalloc_release_space(inode,
7618                                                      count - (size_t)ret);
7619                 else
7620                         btrfs_delalloc_release_metadata(inode, 0);
7621         }
7622 out:
7623         if (wakeup)
7624                 inode_dio_done(inode);
7625         if (relock)
7626                 mutex_lock(&inode->i_mutex);
7627
7628         return ret;
7629 }
7630
7631 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
7632
7633 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
7634                 __u64 start, __u64 len)
7635 {
7636         int     ret;
7637
7638         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
7639         if (ret)
7640                 return ret;
7641
7642         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
7643 }
7644
7645 int btrfs_readpage(struct file *file, struct page *page)
7646 {
7647         struct extent_io_tree *tree;
7648         tree = &BTRFS_I(page->mapping->host)->io_tree;
7649         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
7650 }
7651
7652 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
7653 {
7654         struct extent_io_tree *tree;
7655
7656
7657         if (current->flags & PF_MEMALLOC) {
7658                 redirty_page_for_writepage(wbc, page);
7659                 unlock_page(page);
7660                 return 0;
7661         }
7662         tree = &BTRFS_I(page->mapping->host)->io_tree;
7663         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
7664 }
7665
7666 static int btrfs_writepages(struct address_space *mapping,
7667                             struct writeback_control *wbc)
7668 {
7669         struct extent_io_tree *tree;
7670
7671         tree = &BTRFS_I(mapping->host)->io_tree;
7672         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
7673 }
7674
7675 static int
7676 btrfs_readpages(struct file *file, struct address_space *mapping,
7677                 struct list_head *pages, unsigned nr_pages)
7678 {
7679         struct extent_io_tree *tree;
7680         tree = &BTRFS_I(mapping->host)->io_tree;
7681         return extent_readpages(tree, mapping, pages, nr_pages,
7682                                 btrfs_get_extent);
7683 }
7684 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7685 {
7686         struct extent_io_tree *tree;
7687         struct extent_map_tree *map;
7688         int ret;
7689
7690         tree = &BTRFS_I(page->mapping->host)->io_tree;
7691         map = &BTRFS_I(page->mapping->host)->extent_tree;
7692         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
7693         if (ret == 1) {
7694                 ClearPagePrivate(page);
7695                 set_page_private(page, 0);
7696                 page_cache_release(page);
7697         }
7698         return ret;
7699 }
7700
7701 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7702 {
7703         if (PageWriteback(page) || PageDirty(page))
7704                 return 0;
7705         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
7706 }
7707
7708 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
7709                                  unsigned int length)
7710 {
7711         struct inode *inode = page->mapping->host;
7712         struct extent_io_tree *tree;
7713         struct btrfs_ordered_extent *ordered;
7714         struct extent_state *cached_state = NULL;
7715         u64 page_start = page_offset(page);
7716         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
7717         int inode_evicting = inode->i_state & I_FREEING;
7718
7719         /*
7720          * we have the page locked, so new writeback can't start,
7721          * and the dirty bit won't be cleared while we are here.
7722          *
7723          * Wait for IO on this page so that we can safely clear
7724          * the PagePrivate2 bit and do ordered accounting
7725          */
7726         wait_on_page_writeback(page);
7727
7728         tree = &BTRFS_I(inode)->io_tree;
7729         if (offset) {
7730                 btrfs_releasepage(page, GFP_NOFS);
7731                 return;
7732         }
7733
7734         if (!inode_evicting)
7735                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
7736         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7737         if (ordered) {
7738                 /*
7739                  * IO on this page will never be started, so we need
7740                  * to account for any ordered extents now
7741                  */
7742                 if (!inode_evicting)
7743                         clear_extent_bit(tree, page_start, page_end,
7744                                          EXTENT_DIRTY | EXTENT_DELALLOC |
7745                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
7746                                          EXTENT_DEFRAG, 1, 0, &cached_state,
7747                                          GFP_NOFS);
7748                 /*
7749                  * whoever cleared the private bit is responsible
7750                  * for the finish_ordered_io
7751                  */
7752                 if (TestClearPagePrivate2(page)) {
7753                         struct btrfs_ordered_inode_tree *tree;
7754                         u64 new_len;
7755
7756                         tree = &BTRFS_I(inode)->ordered_tree;
7757
7758                         spin_lock_irq(&tree->lock);
7759                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
7760                         new_len = page_start - ordered->file_offset;
7761                         if (new_len < ordered->truncated_len)
7762                                 ordered->truncated_len = new_len;
7763                         spin_unlock_irq(&tree->lock);
7764
7765                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
7766                                                            page_start,
7767                                                            PAGE_CACHE_SIZE, 1))
7768                                 btrfs_finish_ordered_io(ordered);
7769                 }
7770                 btrfs_put_ordered_extent(ordered);
7771                 if (!inode_evicting) {
7772                         cached_state = NULL;
7773                         lock_extent_bits(tree, page_start, page_end, 0,
7774                                          &cached_state);
7775                 }
7776         }
7777
7778         if (!inode_evicting) {
7779                 clear_extent_bit(tree, page_start, page_end,
7780                                  EXTENT_LOCKED | EXTENT_DIRTY |
7781                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
7782                                  EXTENT_DEFRAG, 1, 1,
7783                                  &cached_state, GFP_NOFS);
7784
7785                 __btrfs_releasepage(page, GFP_NOFS);
7786         }
7787
7788         ClearPageChecked(page);
7789         if (PagePrivate(page)) {
7790                 ClearPagePrivate(page);
7791                 set_page_private(page, 0);
7792                 page_cache_release(page);
7793         }
7794 }
7795
7796 /*
7797  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
7798  * called from a page fault handler when a page is first dirtied. Hence we must
7799  * be careful to check for EOF conditions here. We set the page up correctly
7800  * for a written page which means we get ENOSPC checking when writing into
7801  * holes and correct delalloc and unwritten extent mapping on filesystems that
7802  * support these features.
7803  *
7804  * We are not allowed to take the i_mutex here so we have to play games to
7805  * protect against truncate races as the page could now be beyond EOF.  Because
7806  * vmtruncate() writes the inode size before removing pages, once we have the
7807  * page lock we can determine safely if the page is beyond EOF. If it is not
7808  * beyond EOF, then the page is guaranteed safe against truncation until we
7809  * unlock the page.
7810  */
7811 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
7812 {
7813         struct page *page = vmf->page;
7814         struct inode *inode = file_inode(vma->vm_file);
7815         struct btrfs_root *root = BTRFS_I(inode)->root;
7816         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7817         struct btrfs_ordered_extent *ordered;
7818         struct extent_state *cached_state = NULL;
7819         char *kaddr;
7820         unsigned long zero_start;
7821         loff_t size;
7822         int ret;
7823         int reserved = 0;
7824         u64 page_start;
7825         u64 page_end;
7826
7827         sb_start_pagefault(inode->i_sb);
7828         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
7829         if (!ret) {
7830                 ret = file_update_time(vma->vm_file);
7831                 reserved = 1;
7832         }
7833         if (ret) {
7834                 if (ret == -ENOMEM)
7835                         ret = VM_FAULT_OOM;
7836                 else /* -ENOSPC, -EIO, etc */
7837                         ret = VM_FAULT_SIGBUS;
7838                 if (reserved)
7839                         goto out;
7840                 goto out_noreserve;
7841         }
7842
7843         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
7844 again:
7845         lock_page(page);
7846         size = i_size_read(inode);
7847         page_start = page_offset(page);
7848         page_end = page_start + PAGE_CACHE_SIZE - 1;
7849
7850         if ((page->mapping != inode->i_mapping) ||
7851             (page_start >= size)) {
7852                 /* page got truncated out from underneath us */
7853                 goto out_unlock;
7854         }
7855         wait_on_page_writeback(page);
7856
7857         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
7858         set_page_extent_mapped(page);
7859
7860         /*
7861          * we can't set the delalloc bits if there are pending ordered
7862          * extents.  Drop our locks and wait for them to finish
7863          */
7864         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7865         if (ordered) {
7866                 unlock_extent_cached(io_tree, page_start, page_end,
7867                                      &cached_state, GFP_NOFS);
7868                 unlock_page(page);
7869                 btrfs_start_ordered_extent(inode, ordered, 1);
7870                 btrfs_put_ordered_extent(ordered);
7871                 goto again;
7872         }
7873
7874         /*
7875          * XXX - page_mkwrite gets called every time the page is dirtied, even
7876          * if it was already dirty, so for space accounting reasons we need to
7877          * clear any delalloc bits for the range we are fixing to save.  There
7878          * is probably a better way to do this, but for now keep consistent with
7879          * prepare_pages in the normal write path.
7880          */
7881         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
7882                           EXTENT_DIRTY | EXTENT_DELALLOC |
7883                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
7884                           0, 0, &cached_state, GFP_NOFS);
7885
7886         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
7887                                         &cached_state);
7888         if (ret) {
7889                 unlock_extent_cached(io_tree, page_start, page_end,
7890                                      &cached_state, GFP_NOFS);
7891                 ret = VM_FAULT_SIGBUS;
7892                 goto out_unlock;
7893         }
7894         ret = 0;
7895
7896         /* page is wholly or partially inside EOF */
7897         if (page_start + PAGE_CACHE_SIZE > size)
7898                 zero_start = size & ~PAGE_CACHE_MASK;
7899         else
7900                 zero_start = PAGE_CACHE_SIZE;
7901
7902         if (zero_start != PAGE_CACHE_SIZE) {
7903                 kaddr = kmap(page);
7904                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
7905                 flush_dcache_page(page);
7906                 kunmap(page);
7907         }
7908         ClearPageChecked(page);
7909         set_page_dirty(page);
7910         SetPageUptodate(page);
7911
7912         BTRFS_I(inode)->last_trans = root->fs_info->generation;
7913         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
7914         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
7915
7916         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
7917
7918 out_unlock:
7919         if (!ret) {
7920                 sb_end_pagefault(inode->i_sb);
7921                 return VM_FAULT_LOCKED;
7922         }
7923         unlock_page(page);
7924 out:
7925         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
7926 out_noreserve:
7927         sb_end_pagefault(inode->i_sb);
7928         return ret;
7929 }
7930
7931 static int btrfs_truncate(struct inode *inode)
7932 {
7933         struct btrfs_root *root = BTRFS_I(inode)->root;
7934         struct btrfs_block_rsv *rsv;
7935         int ret = 0;
7936         int err = 0;
7937         struct btrfs_trans_handle *trans;
7938         u64 mask = root->sectorsize - 1;
7939         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
7940
7941         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
7942                                        (u64)-1);
7943         if (ret)
7944                 return ret;
7945
7946         /*
7947          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
7948          * 3 things going on here
7949          *
7950          * 1) We need to reserve space for our orphan item and the space to
7951          * delete our orphan item.  Lord knows we don't want to have a dangling
7952          * orphan item because we didn't reserve space to remove it.
7953          *
7954          * 2) We need to reserve space to update our inode.
7955          *
7956          * 3) We need to have something to cache all the space that is going to
7957          * be free'd up by the truncate operation, but also have some slack
7958          * space reserved in case it uses space during the truncate (thank you
7959          * very much snapshotting).
7960          *
7961          * And we need these to all be seperate.  The fact is we can use alot of
7962          * space doing the truncate, and we have no earthly idea how much space
7963          * we will use, so we need the truncate reservation to be seperate so it
7964          * doesn't end up using space reserved for updating the inode or
7965          * removing the orphan item.  We also need to be able to stop the
7966          * transaction and start a new one, which means we need to be able to
7967          * update the inode several times, and we have no idea of knowing how
7968          * many times that will be, so we can't just reserve 1 item for the
7969          * entirety of the opration, so that has to be done seperately as well.
7970          * Then there is the orphan item, which does indeed need to be held on
7971          * to for the whole operation, and we need nobody to touch this reserved
7972          * space except the orphan code.
7973          *
7974          * So that leaves us with
7975          *
7976          * 1) root->orphan_block_rsv - for the orphan deletion.
7977          * 2) rsv - for the truncate reservation, which we will steal from the
7978          * transaction reservation.
7979          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
7980          * updating the inode.
7981          */
7982         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
7983         if (!rsv)
7984                 return -ENOMEM;
7985         rsv->size = min_size;
7986         rsv->failfast = 1;
7987
7988         /*
7989          * 1 for the truncate slack space
7990          * 1 for updating the inode.
7991          */
7992         trans = btrfs_start_transaction(root, 2);
7993         if (IS_ERR(trans)) {
7994                 err = PTR_ERR(trans);
7995                 goto out;
7996         }
7997
7998         /* Migrate the slack space for the truncate to our reserve */
7999         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
8000                                       min_size);
8001         BUG_ON(ret);
8002
8003         /*
8004          * So if we truncate and then write and fsync we normally would just
8005          * write the extents that changed, which is a problem if we need to
8006          * first truncate that entire inode.  So set this flag so we write out
8007          * all of the extents in the inode to the sync log so we're completely
8008          * safe.
8009          */
8010         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
8011         trans->block_rsv = rsv;
8012
8013         while (1) {
8014                 ret = btrfs_truncate_inode_items(trans, root, inode,
8015                                                  inode->i_size,
8016                                                  BTRFS_EXTENT_DATA_KEY);
8017                 if (ret != -ENOSPC) {
8018                         err = ret;
8019                         break;
8020                 }
8021
8022                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8023                 ret = btrfs_update_inode(trans, root, inode);
8024                 if (ret) {
8025                         err = ret;
8026                         break;
8027                 }
8028
8029                 btrfs_end_transaction(trans, root);
8030                 btrfs_btree_balance_dirty(root);
8031
8032                 trans = btrfs_start_transaction(root, 2);
8033                 if (IS_ERR(trans)) {
8034                         ret = err = PTR_ERR(trans);
8035                         trans = NULL;
8036                         break;
8037                 }
8038
8039                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
8040                                               rsv, min_size);
8041                 BUG_ON(ret);    /* shouldn't happen */
8042                 trans->block_rsv = rsv;
8043         }
8044
8045         if (ret == 0 && inode->i_nlink > 0) {
8046                 trans->block_rsv = root->orphan_block_rsv;
8047                 ret = btrfs_orphan_del(trans, inode);
8048                 if (ret)
8049                         err = ret;
8050         }
8051
8052         if (trans) {
8053                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8054                 ret = btrfs_update_inode(trans, root, inode);
8055                 if (ret && !err)
8056                         err = ret;
8057
8058                 ret = btrfs_end_transaction(trans, root);
8059                 btrfs_btree_balance_dirty(root);
8060         }
8061
8062 out:
8063         btrfs_free_block_rsv(root, rsv);
8064
8065         if (ret && !err)
8066                 err = ret;
8067
8068         return err;
8069 }
8070
8071 /*
8072  * create a new subvolume directory/inode (helper for the ioctl).
8073  */
8074 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
8075                              struct btrfs_root *new_root,
8076                              struct btrfs_root *parent_root,
8077                              u64 new_dirid)
8078 {
8079         struct inode *inode;
8080         int err;
8081         u64 index = 0;
8082
8083         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
8084                                 new_dirid, new_dirid,
8085                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
8086                                 &index);
8087         if (IS_ERR(inode))
8088                 return PTR_ERR(inode);
8089         inode->i_op = &btrfs_dir_inode_operations;
8090         inode->i_fop = &btrfs_dir_file_operations;
8091
8092         set_nlink(inode, 1);
8093         btrfs_i_size_write(inode, 0);
8094
8095         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
8096         if (err)
8097                 btrfs_err(new_root->fs_info,
8098                           "error inheriting subvolume %llu properties: %d",
8099                           new_root->root_key.objectid, err);
8100
8101         err = btrfs_update_inode(trans, new_root, inode);
8102
8103         iput(inode);
8104         return err;
8105 }
8106
8107 struct inode *btrfs_alloc_inode(struct super_block *sb)
8108 {
8109         struct btrfs_inode *ei;
8110         struct inode *inode;
8111
8112         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
8113         if (!ei)
8114                 return NULL;
8115
8116         ei->root = NULL;
8117         ei->generation = 0;
8118         ei->last_trans = 0;
8119         ei->last_sub_trans = 0;
8120         ei->logged_trans = 0;
8121         ei->delalloc_bytes = 0;
8122         ei->disk_i_size = 0;
8123         ei->flags = 0;
8124         ei->csum_bytes = 0;
8125         ei->index_cnt = (u64)-1;
8126         ei->dir_index = 0;
8127         ei->last_unlink_trans = 0;
8128         ei->last_log_commit = 0;
8129
8130         spin_lock_init(&ei->lock);
8131         ei->outstanding_extents = 0;
8132         ei->reserved_extents = 0;
8133
8134         ei->runtime_flags = 0;
8135         ei->force_compress = BTRFS_COMPRESS_NONE;
8136
8137         ei->delayed_node = NULL;
8138
8139         inode = &ei->vfs_inode;
8140         extent_map_tree_init(&ei->extent_tree);
8141         extent_io_tree_init(&ei->io_tree, &inode->i_data);
8142         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
8143         ei->io_tree.track_uptodate = 1;
8144         ei->io_failure_tree.track_uptodate = 1;
8145         atomic_set(&ei->sync_writers, 0);
8146         mutex_init(&ei->log_mutex);
8147         mutex_init(&ei->delalloc_mutex);
8148         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
8149         INIT_LIST_HEAD(&ei->delalloc_inodes);
8150         RB_CLEAR_NODE(&ei->rb_node);
8151
8152         return inode;
8153 }
8154
8155 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8156 void btrfs_test_destroy_inode(struct inode *inode)
8157 {
8158         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8159         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8160 }
8161 #endif
8162
8163 static void btrfs_i_callback(struct rcu_head *head)
8164 {
8165         struct inode *inode = container_of(head, struct inode, i_rcu);
8166         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8167 }
8168
8169 void btrfs_destroy_inode(struct inode *inode)
8170 {
8171         struct btrfs_ordered_extent *ordered;
8172         struct btrfs_root *root = BTRFS_I(inode)->root;
8173
8174         WARN_ON(!hlist_empty(&inode->i_dentry));
8175         WARN_ON(inode->i_data.nrpages);
8176         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8177         WARN_ON(BTRFS_I(inode)->reserved_extents);
8178         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8179         WARN_ON(BTRFS_I(inode)->csum_bytes);
8180
8181         /*
8182          * This can happen where we create an inode, but somebody else also
8183          * created the same inode and we need to destroy the one we already
8184          * created.
8185          */
8186         if (!root)
8187                 goto free;
8188
8189         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
8190                      &BTRFS_I(inode)->runtime_flags)) {
8191                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
8192                         btrfs_ino(inode));
8193                 atomic_dec(&root->orphan_inodes);
8194         }
8195
8196         while (1) {
8197                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8198                 if (!ordered)
8199                         break;
8200                 else {
8201                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
8202                                 ordered->file_offset, ordered->len);
8203                         btrfs_remove_ordered_extent(inode, ordered);
8204                         btrfs_put_ordered_extent(ordered);
8205                         btrfs_put_ordered_extent(ordered);
8206                 }
8207         }
8208         inode_tree_del(inode);
8209         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8210 free:
8211         call_rcu(&inode->i_rcu, btrfs_i_callback);
8212 }
8213
8214 int btrfs_drop_inode(struct inode *inode)
8215 {
8216         struct btrfs_root *root = BTRFS_I(inode)->root;
8217
8218         if (root == NULL)
8219                 return 1;
8220
8221         /* the snap/subvol tree is on deleting */
8222         if (btrfs_root_refs(&root->root_item) == 0)
8223                 return 1;
8224         else
8225                 return generic_drop_inode(inode);
8226 }
8227
8228 static void init_once(void *foo)
8229 {
8230         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8231
8232         inode_init_once(&ei->vfs_inode);
8233 }
8234
8235 void btrfs_destroy_cachep(void)
8236 {
8237         /*
8238          * Make sure all delayed rcu free inodes are flushed before we
8239          * destroy cache.
8240          */
8241         rcu_barrier();
8242         if (btrfs_inode_cachep)
8243                 kmem_cache_destroy(btrfs_inode_cachep);
8244         if (btrfs_trans_handle_cachep)
8245                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8246         if (btrfs_transaction_cachep)
8247                 kmem_cache_destroy(btrfs_transaction_cachep);
8248         if (btrfs_path_cachep)
8249                 kmem_cache_destroy(btrfs_path_cachep);
8250         if (btrfs_free_space_cachep)
8251                 kmem_cache_destroy(btrfs_free_space_cachep);
8252         if (btrfs_delalloc_work_cachep)
8253                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8254 }
8255
8256 int btrfs_init_cachep(void)
8257 {
8258         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8259                         sizeof(struct btrfs_inode), 0,
8260                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8261         if (!btrfs_inode_cachep)
8262                 goto fail;
8263
8264         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8265                         sizeof(struct btrfs_trans_handle), 0,
8266                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8267         if (!btrfs_trans_handle_cachep)
8268                 goto fail;
8269
8270         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8271                         sizeof(struct btrfs_transaction), 0,
8272                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8273         if (!btrfs_transaction_cachep)
8274                 goto fail;
8275
8276         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8277                         sizeof(struct btrfs_path), 0,
8278                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8279         if (!btrfs_path_cachep)
8280                 goto fail;
8281
8282         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8283                         sizeof(struct btrfs_free_space), 0,
8284                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8285         if (!btrfs_free_space_cachep)
8286                 goto fail;
8287
8288         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8289                         sizeof(struct btrfs_delalloc_work), 0,
8290                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8291                         NULL);
8292         if (!btrfs_delalloc_work_cachep)
8293                 goto fail;
8294
8295         return 0;
8296 fail:
8297         btrfs_destroy_cachep();
8298         return -ENOMEM;
8299 }
8300
8301 static int btrfs_getattr(struct vfsmount *mnt,
8302                          struct dentry *dentry, struct kstat *stat)
8303 {
8304         u64 delalloc_bytes;
8305         struct inode *inode = dentry->d_inode;
8306         u32 blocksize = inode->i_sb->s_blocksize;
8307
8308         generic_fillattr(inode, stat);
8309         stat->dev = BTRFS_I(inode)->root->anon_dev;
8310         stat->blksize = PAGE_CACHE_SIZE;
8311
8312         spin_lock(&BTRFS_I(inode)->lock);
8313         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8314         spin_unlock(&BTRFS_I(inode)->lock);
8315         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8316                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8317         return 0;
8318 }
8319
8320 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8321                            struct inode *new_dir, struct dentry *new_dentry)
8322 {
8323         struct btrfs_trans_handle *trans;
8324         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8325         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8326         struct inode *new_inode = new_dentry->d_inode;
8327         struct inode *old_inode = old_dentry->d_inode;
8328         struct timespec ctime = CURRENT_TIME;
8329         u64 index = 0;
8330         u64 root_objectid;
8331         int ret;
8332         u64 old_ino = btrfs_ino(old_inode);
8333
8334         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8335                 return -EPERM;
8336
8337         /* we only allow rename subvolume link between subvolumes */
8338         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8339                 return -EXDEV;
8340
8341         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8342             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8343                 return -ENOTEMPTY;
8344
8345         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8346             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8347                 return -ENOTEMPTY;
8348
8349
8350         /* check for collisions, even if the  name isn't there */
8351         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8352                              new_dentry->d_name.name,
8353                              new_dentry->d_name.len);
8354
8355         if (ret) {
8356                 if (ret == -EEXIST) {
8357                         /* we shouldn't get
8358                          * eexist without a new_inode */
8359                         if (WARN_ON(!new_inode)) {
8360                                 return ret;
8361                         }
8362                 } else {
8363                         /* maybe -EOVERFLOW */
8364                         return ret;
8365                 }
8366         }
8367         ret = 0;
8368
8369         /*
8370          * we're using rename to replace one file with another.  Start IO on it
8371          * now so  we don't add too much work to the end of the transaction
8372          */
8373         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
8374                 filemap_flush(old_inode->i_mapping);
8375
8376         /* close the racy window with snapshot create/destroy ioctl */
8377         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8378                 down_read(&root->fs_info->subvol_sem);
8379         /*
8380          * We want to reserve the absolute worst case amount of items.  So if
8381          * both inodes are subvols and we need to unlink them then that would
8382          * require 4 item modifications, but if they are both normal inodes it
8383          * would require 5 item modifications, so we'll assume their normal
8384          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8385          * should cover the worst case number of items we'll modify.
8386          */
8387         trans = btrfs_start_transaction(root, 11);
8388         if (IS_ERR(trans)) {
8389                 ret = PTR_ERR(trans);
8390                 goto out_notrans;
8391         }
8392
8393         if (dest != root)
8394                 btrfs_record_root_in_trans(trans, dest);
8395
8396         ret = btrfs_set_inode_index(new_dir, &index);
8397         if (ret)
8398                 goto out_fail;
8399
8400         BTRFS_I(old_inode)->dir_index = 0ULL;
8401         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8402                 /* force full log commit if subvolume involved. */
8403                 btrfs_set_log_full_commit(root->fs_info, trans);
8404         } else {
8405                 ret = btrfs_insert_inode_ref(trans, dest,
8406                                              new_dentry->d_name.name,
8407                                              new_dentry->d_name.len,
8408                                              old_ino,
8409                                              btrfs_ino(new_dir), index);
8410                 if (ret)
8411                         goto out_fail;
8412                 /*
8413                  * this is an ugly little race, but the rename is required
8414                  * to make sure that if we crash, the inode is either at the
8415                  * old name or the new one.  pinning the log transaction lets
8416                  * us make sure we don't allow a log commit to come in after
8417                  * we unlink the name but before we add the new name back in.
8418                  */
8419                 btrfs_pin_log_trans(root);
8420         }
8421
8422         inode_inc_iversion(old_dir);
8423         inode_inc_iversion(new_dir);
8424         inode_inc_iversion(old_inode);
8425         old_dir->i_ctime = old_dir->i_mtime = ctime;
8426         new_dir->i_ctime = new_dir->i_mtime = ctime;
8427         old_inode->i_ctime = ctime;
8428
8429         if (old_dentry->d_parent != new_dentry->d_parent)
8430                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8431
8432         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8433                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8434                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8435                                         old_dentry->d_name.name,
8436                                         old_dentry->d_name.len);
8437         } else {
8438                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8439                                         old_dentry->d_inode,
8440                                         old_dentry->d_name.name,
8441                                         old_dentry->d_name.len);
8442                 if (!ret)
8443                         ret = btrfs_update_inode(trans, root, old_inode);
8444         }
8445         if (ret) {
8446                 btrfs_abort_transaction(trans, root, ret);
8447                 goto out_fail;
8448         }
8449
8450         if (new_inode) {
8451                 inode_inc_iversion(new_inode);
8452                 new_inode->i_ctime = CURRENT_TIME;
8453                 if (unlikely(btrfs_ino(new_inode) ==
8454                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8455                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8456                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8457                                                 root_objectid,
8458                                                 new_dentry->d_name.name,
8459                                                 new_dentry->d_name.len);
8460                         BUG_ON(new_inode->i_nlink == 0);
8461                 } else {
8462                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8463                                                  new_dentry->d_inode,
8464                                                  new_dentry->d_name.name,
8465                                                  new_dentry->d_name.len);
8466                 }
8467                 if (!ret && new_inode->i_nlink == 0)
8468                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8469                 if (ret) {
8470                         btrfs_abort_transaction(trans, root, ret);
8471                         goto out_fail;
8472                 }
8473         }
8474
8475         ret = btrfs_add_link(trans, new_dir, old_inode,
8476                              new_dentry->d_name.name,
8477                              new_dentry->d_name.len, 0, index);
8478         if (ret) {
8479                 btrfs_abort_transaction(trans, root, ret);
8480                 goto out_fail;
8481         }
8482
8483         if (old_inode->i_nlink == 1)
8484                 BTRFS_I(old_inode)->dir_index = index;
8485
8486         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8487                 struct dentry *parent = new_dentry->d_parent;
8488                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8489                 btrfs_end_log_trans(root);
8490         }
8491 out_fail:
8492         btrfs_end_transaction(trans, root);
8493 out_notrans:
8494         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8495                 up_read(&root->fs_info->subvol_sem);
8496
8497         return ret;
8498 }
8499
8500 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8501 {
8502         struct btrfs_delalloc_work *delalloc_work;
8503         struct inode *inode;
8504
8505         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8506                                      work);
8507         inode = delalloc_work->inode;
8508         if (delalloc_work->wait) {
8509                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8510         } else {
8511                 filemap_flush(inode->i_mapping);
8512                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8513                              &BTRFS_I(inode)->runtime_flags))
8514                         filemap_flush(inode->i_mapping);
8515         }
8516
8517         if (delalloc_work->delay_iput)
8518                 btrfs_add_delayed_iput(inode);
8519         else
8520                 iput(inode);
8521         complete(&delalloc_work->completion);
8522 }
8523
8524 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8525                                                     int wait, int delay_iput)
8526 {
8527         struct btrfs_delalloc_work *work;
8528
8529         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
8530         if (!work)
8531                 return NULL;
8532
8533         init_completion(&work->completion);
8534         INIT_LIST_HEAD(&work->list);
8535         work->inode = inode;
8536         work->wait = wait;
8537         work->delay_iput = delay_iput;
8538         btrfs_init_work(&work->work, btrfs_run_delalloc_work, NULL, NULL);
8539
8540         return work;
8541 }
8542
8543 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
8544 {
8545         wait_for_completion(&work->completion);
8546         kmem_cache_free(btrfs_delalloc_work_cachep, work);
8547 }
8548
8549 /*
8550  * some fairly slow code that needs optimization. This walks the list
8551  * of all the inodes with pending delalloc and forces them to disk.
8552  */
8553 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
8554                                    int nr)
8555 {
8556         struct btrfs_inode *binode;
8557         struct inode *inode;
8558         struct btrfs_delalloc_work *work, *next;
8559         struct list_head works;
8560         struct list_head splice;
8561         int ret = 0;
8562
8563         INIT_LIST_HEAD(&works);
8564         INIT_LIST_HEAD(&splice);
8565
8566         mutex_lock(&root->delalloc_mutex);
8567         spin_lock(&root->delalloc_lock);
8568         list_splice_init(&root->delalloc_inodes, &splice);
8569         while (!list_empty(&splice)) {
8570                 binode = list_entry(splice.next, struct btrfs_inode,
8571                                     delalloc_inodes);
8572
8573                 list_move_tail(&binode->delalloc_inodes,
8574                                &root->delalloc_inodes);
8575                 inode = igrab(&binode->vfs_inode);
8576                 if (!inode) {
8577                         cond_resched_lock(&root->delalloc_lock);
8578                         continue;
8579                 }
8580                 spin_unlock(&root->delalloc_lock);
8581
8582                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
8583                 if (unlikely(!work)) {
8584                         if (delay_iput)
8585                                 btrfs_add_delayed_iput(inode);
8586                         else
8587                                 iput(inode);
8588                         ret = -ENOMEM;
8589                         goto out;
8590                 }
8591                 list_add_tail(&work->list, &works);
8592                 btrfs_queue_work(root->fs_info->flush_workers,
8593                                  &work->work);
8594                 ret++;
8595                 if (nr != -1 && ret >= nr)
8596                         goto out;
8597                 cond_resched();
8598                 spin_lock(&root->delalloc_lock);
8599         }
8600         spin_unlock(&root->delalloc_lock);
8601
8602 out:
8603         list_for_each_entry_safe(work, next, &works, list) {
8604                 list_del_init(&work->list);
8605                 btrfs_wait_and_free_delalloc_work(work);
8606         }
8607
8608         if (!list_empty_careful(&splice)) {
8609                 spin_lock(&root->delalloc_lock);
8610                 list_splice_tail(&splice, &root->delalloc_inodes);
8611                 spin_unlock(&root->delalloc_lock);
8612         }
8613         mutex_unlock(&root->delalloc_mutex);
8614         return ret;
8615 }
8616
8617 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
8618 {
8619         int ret;
8620
8621         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
8622                 return -EROFS;
8623
8624         ret = __start_delalloc_inodes(root, delay_iput, -1);
8625         if (ret > 0)
8626                 ret = 0;
8627         /*
8628          * the filemap_flush will queue IO into the worker threads, but
8629          * we have to make sure the IO is actually started and that
8630          * ordered extents get created before we return
8631          */
8632         atomic_inc(&root->fs_info->async_submit_draining);
8633         while (atomic_read(&root->fs_info->nr_async_submits) ||
8634               atomic_read(&root->fs_info->async_delalloc_pages)) {
8635                 wait_event(root->fs_info->async_submit_wait,
8636                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
8637                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
8638         }
8639         atomic_dec(&root->fs_info->async_submit_draining);
8640         return ret;
8641 }
8642
8643 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
8644                                int nr)
8645 {
8646         struct btrfs_root *root;
8647         struct list_head splice;
8648         int ret;
8649
8650         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
8651                 return -EROFS;
8652
8653         INIT_LIST_HEAD(&splice);
8654
8655         mutex_lock(&fs_info->delalloc_root_mutex);
8656         spin_lock(&fs_info->delalloc_root_lock);
8657         list_splice_init(&fs_info->delalloc_roots, &splice);
8658         while (!list_empty(&splice) && nr) {
8659                 root = list_first_entry(&splice, struct btrfs_root,
8660                                         delalloc_root);
8661                 root = btrfs_grab_fs_root(root);
8662                 BUG_ON(!root);
8663                 list_move_tail(&root->delalloc_root,
8664                                &fs_info->delalloc_roots);
8665                 spin_unlock(&fs_info->delalloc_root_lock);
8666
8667                 ret = __start_delalloc_inodes(root, delay_iput, nr);
8668                 btrfs_put_fs_root(root);
8669                 if (ret < 0)
8670                         goto out;
8671
8672                 if (nr != -1) {
8673                         nr -= ret;
8674                         WARN_ON(nr < 0);
8675                 }
8676                 spin_lock(&fs_info->delalloc_root_lock);
8677         }
8678         spin_unlock(&fs_info->delalloc_root_lock);
8679
8680         ret = 0;
8681         atomic_inc(&fs_info->async_submit_draining);
8682         while (atomic_read(&fs_info->nr_async_submits) ||
8683               atomic_read(&fs_info->async_delalloc_pages)) {
8684                 wait_event(fs_info->async_submit_wait,
8685                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
8686                     atomic_read(&fs_info->async_delalloc_pages) == 0));
8687         }
8688         atomic_dec(&fs_info->async_submit_draining);
8689 out:
8690         if (!list_empty_careful(&splice)) {
8691                 spin_lock(&fs_info->delalloc_root_lock);
8692                 list_splice_tail(&splice, &fs_info->delalloc_roots);
8693                 spin_unlock(&fs_info->delalloc_root_lock);
8694         }
8695         mutex_unlock(&fs_info->delalloc_root_mutex);
8696         return ret;
8697 }
8698
8699 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
8700                          const char *symname)
8701 {
8702         struct btrfs_trans_handle *trans;
8703         struct btrfs_root *root = BTRFS_I(dir)->root;
8704         struct btrfs_path *path;
8705         struct btrfs_key key;
8706         struct inode *inode = NULL;
8707         int err;
8708         int drop_inode = 0;
8709         u64 objectid;
8710         u64 index = 0;
8711         int name_len;
8712         int datasize;
8713         unsigned long ptr;
8714         struct btrfs_file_extent_item *ei;
8715         struct extent_buffer *leaf;
8716
8717         name_len = strlen(symname);
8718         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
8719                 return -ENAMETOOLONG;
8720
8721         /*
8722          * 2 items for inode item and ref
8723          * 2 items for dir items
8724          * 1 item for xattr if selinux is on
8725          */
8726         trans = btrfs_start_transaction(root, 5);
8727         if (IS_ERR(trans))
8728                 return PTR_ERR(trans);
8729
8730         err = btrfs_find_free_ino(root, &objectid);
8731         if (err)
8732                 goto out_unlock;
8733
8734         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
8735                                 dentry->d_name.len, btrfs_ino(dir), objectid,
8736                                 S_IFLNK|S_IRWXUGO, &index);
8737         if (IS_ERR(inode)) {
8738                 err = PTR_ERR(inode);
8739                 goto out_unlock;
8740         }
8741
8742         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
8743         if (err) {
8744                 drop_inode = 1;
8745                 goto out_unlock;
8746         }
8747
8748         /*
8749         * If the active LSM wants to access the inode during
8750         * d_instantiate it needs these. Smack checks to see
8751         * if the filesystem supports xattrs by looking at the
8752         * ops vector.
8753         */
8754         inode->i_fop = &btrfs_file_operations;
8755         inode->i_op = &btrfs_file_inode_operations;
8756
8757         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
8758         if (err)
8759                 drop_inode = 1;
8760         else {
8761                 inode->i_mapping->a_ops = &btrfs_aops;
8762                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8763                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
8764         }
8765         if (drop_inode)
8766                 goto out_unlock;
8767
8768         path = btrfs_alloc_path();
8769         if (!path) {
8770                 err = -ENOMEM;
8771                 drop_inode = 1;
8772                 goto out_unlock;
8773         }
8774         key.objectid = btrfs_ino(inode);
8775         key.offset = 0;
8776         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
8777         datasize = btrfs_file_extent_calc_inline_size(name_len);
8778         err = btrfs_insert_empty_item(trans, root, path, &key,
8779                                       datasize);
8780         if (err) {
8781                 drop_inode = 1;
8782                 btrfs_free_path(path);
8783                 goto out_unlock;
8784         }
8785         leaf = path->nodes[0];
8786         ei = btrfs_item_ptr(leaf, path->slots[0],
8787                             struct btrfs_file_extent_item);
8788         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
8789         btrfs_set_file_extent_type(leaf, ei,
8790                                    BTRFS_FILE_EXTENT_INLINE);
8791         btrfs_set_file_extent_encryption(leaf, ei, 0);
8792         btrfs_set_file_extent_compression(leaf, ei, 0);
8793         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
8794         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
8795
8796         ptr = btrfs_file_extent_inline_start(ei);
8797         write_extent_buffer(leaf, symname, ptr, name_len);
8798         btrfs_mark_buffer_dirty(leaf);
8799         btrfs_free_path(path);
8800
8801         inode->i_op = &btrfs_symlink_inode_operations;
8802         inode->i_mapping->a_ops = &btrfs_symlink_aops;
8803         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8804         inode_set_bytes(inode, name_len);
8805         btrfs_i_size_write(inode, name_len);
8806         err = btrfs_update_inode(trans, root, inode);
8807         if (err)
8808                 drop_inode = 1;
8809
8810 out_unlock:
8811         if (!err)
8812                 d_instantiate(dentry, inode);
8813         btrfs_end_transaction(trans, root);
8814         if (drop_inode) {
8815                 inode_dec_link_count(inode);
8816                 iput(inode);
8817         }
8818         btrfs_btree_balance_dirty(root);
8819         return err;
8820 }
8821
8822 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
8823                                        u64 start, u64 num_bytes, u64 min_size,
8824                                        loff_t actual_len, u64 *alloc_hint,
8825                                        struct btrfs_trans_handle *trans)
8826 {
8827         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
8828         struct extent_map *em;
8829         struct btrfs_root *root = BTRFS_I(inode)->root;
8830         struct btrfs_key ins;
8831         u64 cur_offset = start;
8832         u64 i_size;
8833         u64 cur_bytes;
8834         int ret = 0;
8835         bool own_trans = true;
8836
8837         if (trans)
8838                 own_trans = false;
8839         while (num_bytes > 0) {
8840                 if (own_trans) {
8841                         trans = btrfs_start_transaction(root, 3);
8842                         if (IS_ERR(trans)) {
8843                                 ret = PTR_ERR(trans);
8844                                 break;
8845                         }
8846                 }
8847
8848                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
8849                 cur_bytes = max(cur_bytes, min_size);
8850                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
8851                                            *alloc_hint, &ins, 1, 0);
8852                 if (ret) {
8853                         if (own_trans)
8854                                 btrfs_end_transaction(trans, root);
8855                         break;
8856                 }
8857
8858                 ret = insert_reserved_file_extent(trans, inode,
8859                                                   cur_offset, ins.objectid,
8860                                                   ins.offset, ins.offset,
8861                                                   ins.offset, 0, 0, 0,
8862                                                   BTRFS_FILE_EXTENT_PREALLOC);
8863                 if (ret) {
8864                         btrfs_free_reserved_extent(root, ins.objectid,
8865                                                    ins.offset, 0);
8866                         btrfs_abort_transaction(trans, root, ret);
8867                         if (own_trans)
8868                                 btrfs_end_transaction(trans, root);
8869                         break;
8870                 }
8871                 btrfs_drop_extent_cache(inode, cur_offset,
8872                                         cur_offset + ins.offset -1, 0);
8873
8874                 em = alloc_extent_map();
8875                 if (!em) {
8876                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
8877                                 &BTRFS_I(inode)->runtime_flags);
8878                         goto next;
8879                 }
8880
8881                 em->start = cur_offset;
8882                 em->orig_start = cur_offset;
8883                 em->len = ins.offset;
8884                 em->block_start = ins.objectid;
8885                 em->block_len = ins.offset;
8886                 em->orig_block_len = ins.offset;
8887                 em->ram_bytes = ins.offset;
8888                 em->bdev = root->fs_info->fs_devices->latest_bdev;
8889                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
8890                 em->generation = trans->transid;
8891
8892                 while (1) {
8893                         write_lock(&em_tree->lock);
8894                         ret = add_extent_mapping(em_tree, em, 1);
8895                         write_unlock(&em_tree->lock);
8896                         if (ret != -EEXIST)
8897                                 break;
8898                         btrfs_drop_extent_cache(inode, cur_offset,
8899                                                 cur_offset + ins.offset - 1,
8900                                                 0);
8901                 }
8902                 free_extent_map(em);
8903 next:
8904                 num_bytes -= ins.offset;
8905                 cur_offset += ins.offset;
8906                 *alloc_hint = ins.objectid + ins.offset;
8907
8908                 inode_inc_iversion(inode);
8909                 inode->i_ctime = CURRENT_TIME;
8910                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
8911                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
8912                     (actual_len > inode->i_size) &&
8913                     (cur_offset > inode->i_size)) {
8914                         if (cur_offset > actual_len)
8915                                 i_size = actual_len;
8916                         else
8917                                 i_size = cur_offset;
8918                         i_size_write(inode, i_size);
8919                         btrfs_ordered_update_i_size(inode, i_size, NULL);
8920                 }
8921
8922                 ret = btrfs_update_inode(trans, root, inode);
8923
8924                 if (ret) {
8925                         btrfs_abort_transaction(trans, root, ret);
8926                         if (own_trans)
8927                                 btrfs_end_transaction(trans, root);
8928                         break;
8929                 }
8930
8931                 if (own_trans)
8932                         btrfs_end_transaction(trans, root);
8933         }
8934         return ret;
8935 }
8936
8937 int btrfs_prealloc_file_range(struct inode *inode, int mode,
8938                               u64 start, u64 num_bytes, u64 min_size,
8939                               loff_t actual_len, u64 *alloc_hint)
8940 {
8941         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8942                                            min_size, actual_len, alloc_hint,
8943                                            NULL);
8944 }
8945
8946 int btrfs_prealloc_file_range_trans(struct inode *inode,
8947                                     struct btrfs_trans_handle *trans, int mode,
8948                                     u64 start, u64 num_bytes, u64 min_size,
8949                                     loff_t actual_len, u64 *alloc_hint)
8950 {
8951         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8952                                            min_size, actual_len, alloc_hint, trans);
8953 }
8954
8955 static int btrfs_set_page_dirty(struct page *page)
8956 {
8957         return __set_page_dirty_nobuffers(page);
8958 }
8959
8960 static int btrfs_permission(struct inode *inode, int mask)
8961 {
8962         struct btrfs_root *root = BTRFS_I(inode)->root;
8963         umode_t mode = inode->i_mode;
8964
8965         if (mask & MAY_WRITE &&
8966             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
8967                 if (btrfs_root_readonly(root))
8968                         return -EROFS;
8969                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
8970                         return -EACCES;
8971         }
8972         return generic_permission(inode, mask);
8973 }
8974
8975 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
8976 {
8977         struct btrfs_trans_handle *trans;
8978         struct btrfs_root *root = BTRFS_I(dir)->root;
8979         struct inode *inode = NULL;
8980         u64 objectid;
8981         u64 index;
8982         int ret = 0;
8983
8984         /*
8985          * 5 units required for adding orphan entry
8986          */
8987         trans = btrfs_start_transaction(root, 5);
8988         if (IS_ERR(trans))
8989                 return PTR_ERR(trans);
8990
8991         ret = btrfs_find_free_ino(root, &objectid);
8992         if (ret)
8993                 goto out;
8994
8995         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
8996                                 btrfs_ino(dir), objectid, mode, &index);
8997         if (IS_ERR(inode)) {
8998                 ret = PTR_ERR(inode);
8999                 inode = NULL;
9000                 goto out;
9001         }
9002
9003         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
9004         if (ret)
9005                 goto out;
9006
9007         ret = btrfs_update_inode(trans, root, inode);
9008         if (ret)
9009                 goto out;
9010
9011         inode->i_fop = &btrfs_file_operations;
9012         inode->i_op = &btrfs_file_inode_operations;
9013
9014         inode->i_mapping->a_ops = &btrfs_aops;
9015         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
9016         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9017
9018         ret = btrfs_orphan_add(trans, inode);
9019         if (ret)
9020                 goto out;
9021
9022         /*
9023          * We set number of links to 0 in btrfs_new_inode(), and here we set
9024          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
9025          * through:
9026          *
9027          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
9028          */
9029         set_nlink(inode, 1);
9030         d_tmpfile(dentry, inode);
9031         mark_inode_dirty(inode);
9032
9033 out:
9034         btrfs_end_transaction(trans, root);
9035         if (ret)
9036                 iput(inode);
9037         btrfs_balance_delayed_items(root);
9038         btrfs_btree_balance_dirty(root);
9039
9040         return ret;
9041 }
9042
9043 static const struct inode_operations btrfs_dir_inode_operations = {
9044         .getattr        = btrfs_getattr,
9045         .lookup         = btrfs_lookup,
9046         .create         = btrfs_create,
9047         .unlink         = btrfs_unlink,
9048         .link           = btrfs_link,
9049         .mkdir          = btrfs_mkdir,
9050         .rmdir          = btrfs_rmdir,
9051         .rename         = btrfs_rename,
9052         .symlink        = btrfs_symlink,
9053         .setattr        = btrfs_setattr,
9054         .mknod          = btrfs_mknod,
9055         .setxattr       = btrfs_setxattr,
9056         .getxattr       = btrfs_getxattr,
9057         .listxattr      = btrfs_listxattr,
9058         .removexattr    = btrfs_removexattr,
9059         .permission     = btrfs_permission,
9060         .get_acl        = btrfs_get_acl,
9061         .set_acl        = btrfs_set_acl,
9062         .update_time    = btrfs_update_time,
9063         .tmpfile        = btrfs_tmpfile,
9064 };
9065 static const struct inode_operations btrfs_dir_ro_inode_operations = {
9066         .lookup         = btrfs_lookup,
9067         .permission     = btrfs_permission,
9068         .get_acl        = btrfs_get_acl,
9069         .set_acl        = btrfs_set_acl,
9070         .update_time    = btrfs_update_time,
9071 };
9072
9073 static const struct file_operations btrfs_dir_file_operations = {
9074         .llseek         = generic_file_llseek,
9075         .read           = generic_read_dir,
9076         .iterate        = btrfs_real_readdir,
9077         .unlocked_ioctl = btrfs_ioctl,
9078 #ifdef CONFIG_COMPAT
9079         .compat_ioctl   = btrfs_ioctl,
9080 #endif
9081         .release        = btrfs_release_file,
9082         .fsync          = btrfs_sync_file,
9083 };
9084
9085 static struct extent_io_ops btrfs_extent_io_ops = {
9086         .fill_delalloc = run_delalloc_range,
9087         .submit_bio_hook = btrfs_submit_bio_hook,
9088         .merge_bio_hook = btrfs_merge_bio_hook,
9089         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
9090         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
9091         .writepage_start_hook = btrfs_writepage_start_hook,
9092         .set_bit_hook = btrfs_set_bit_hook,
9093         .clear_bit_hook = btrfs_clear_bit_hook,
9094         .merge_extent_hook = btrfs_merge_extent_hook,
9095         .split_extent_hook = btrfs_split_extent_hook,
9096 };
9097
9098 /*
9099  * btrfs doesn't support the bmap operation because swapfiles
9100  * use bmap to make a mapping of extents in the file.  They assume
9101  * these extents won't change over the life of the file and they
9102  * use the bmap result to do IO directly to the drive.
9103  *
9104  * the btrfs bmap call would return logical addresses that aren't
9105  * suitable for IO and they also will change frequently as COW
9106  * operations happen.  So, swapfile + btrfs == corruption.
9107  *
9108  * For now we're avoiding this by dropping bmap.
9109  */
9110 static const struct address_space_operations btrfs_aops = {
9111         .readpage       = btrfs_readpage,
9112         .writepage      = btrfs_writepage,
9113         .writepages     = btrfs_writepages,
9114         .readpages      = btrfs_readpages,
9115         .direct_IO      = btrfs_direct_IO,
9116         .invalidatepage = btrfs_invalidatepage,
9117         .releasepage    = btrfs_releasepage,
9118         .set_page_dirty = btrfs_set_page_dirty,
9119         .error_remove_page = generic_error_remove_page,
9120 };
9121
9122 static const struct address_space_operations btrfs_symlink_aops = {
9123         .readpage       = btrfs_readpage,
9124         .writepage      = btrfs_writepage,
9125         .invalidatepage = btrfs_invalidatepage,
9126         .releasepage    = btrfs_releasepage,
9127 };
9128
9129 static const struct inode_operations btrfs_file_inode_operations = {
9130         .getattr        = btrfs_getattr,
9131         .setattr        = btrfs_setattr,
9132         .setxattr       = btrfs_setxattr,
9133         .getxattr       = btrfs_getxattr,
9134         .listxattr      = btrfs_listxattr,
9135         .removexattr    = btrfs_removexattr,
9136         .permission     = btrfs_permission,
9137         .fiemap         = btrfs_fiemap,
9138         .get_acl        = btrfs_get_acl,
9139         .set_acl        = btrfs_set_acl,
9140         .update_time    = btrfs_update_time,
9141 };
9142 static const struct inode_operations btrfs_special_inode_operations = {
9143         .getattr        = btrfs_getattr,
9144         .setattr        = btrfs_setattr,
9145         .permission     = btrfs_permission,
9146         .setxattr       = btrfs_setxattr,
9147         .getxattr       = btrfs_getxattr,
9148         .listxattr      = btrfs_listxattr,
9149         .removexattr    = btrfs_removexattr,
9150         .get_acl        = btrfs_get_acl,
9151         .set_acl        = btrfs_set_acl,
9152         .update_time    = btrfs_update_time,
9153 };
9154 static const struct inode_operations btrfs_symlink_inode_operations = {
9155         .readlink       = generic_readlink,
9156         .follow_link    = page_follow_link_light,
9157         .put_link       = page_put_link,
9158         .getattr        = btrfs_getattr,
9159         .setattr        = btrfs_setattr,
9160         .permission     = btrfs_permission,
9161         .setxattr       = btrfs_setxattr,
9162         .getxattr       = btrfs_getxattr,
9163         .listxattr      = btrfs_listxattr,
9164         .removexattr    = btrfs_removexattr,
9165         .update_time    = btrfs_update_time,
9166 };
9167
9168 const struct dentry_operations btrfs_dentry_operations = {
9169         .d_delete       = btrfs_dentry_delete,
9170         .d_release      = btrfs_dentry_release,
9171 };