fs/btrfs/ioctl.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/smp_lock.h>
  30 #include <linux/backing-dev.h>
  31 #include <linux/mpage.h>
  32 #include <linux/swap.h>
  33 #include <linux/writeback.h>
  34 #include <linux/statfs.h>
  35 #include <linux/compat.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/version.h>
  38 #include <linux/xattr.h>
  39 #include "ctree.h"
  40 #include "disk-io.h"
  41 #include "transaction.h"
  42 #include "btrfs_inode.h"
  43 #include "ioctl.h"
  44 #include "print-tree.h"
  45 #include "volumes.h"
  46 #include "locking.h"
  47
  48
  49
  50 static noinline int create_subvol(struct btrfs_root *root, char *name,
  51                                   int namelen)
  52 {
  53         struct btrfs_trans_handle *trans;
  54         struct btrfs_key key;
  55         struct btrfs_root_item root_item;
  56         struct btrfs_inode_item *inode_item;
  57         struct extent_buffer *leaf;
  58         struct btrfs_root *new_root = root;
  59         struct inode *dir;
  60         int ret;
  61         int err;
  62         u64 objectid;
  63         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
  64         unsigned long nr = 1;
  65
  66         ret = btrfs_check_free_space(root, 1, 0);
  67         if (ret)
  68                 goto fail_commit;
  69
  70         trans = btrfs_start_transaction(root, 1);
  71         BUG_ON(!trans);
  72
  73         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
  74                                        0, &objectid);
  75         if (ret)
  76                 goto fail;
  77
  78         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
  79                                       objectid, trans->transid, 0, 0,
  80                                       0, 0);
  81         if (IS_ERR(leaf))
  82                 return PTR_ERR(leaf);
  83
  84         btrfs_set_header_nritems(leaf, 0);
  85         btrfs_set_header_level(leaf, 0);
  86         btrfs_set_header_bytenr(leaf, leaf->start);
  87         btrfs_set_header_generation(leaf, trans->transid);
  88         btrfs_set_header_owner(leaf, objectid);
  89
  90         write_extent_buffer(leaf, root->fs_info->fsid,
  91                             (unsigned long)btrfs_header_fsid(leaf),
  92                             BTRFS_FSID_SIZE);
  93         btrfs_mark_buffer_dirty(leaf);
  94
  95         inode_item = &root_item.inode;
  96         memset(inode_item, 0, sizeof(*inode_item));
  97         inode_item->generation = cpu_to_le64(1);
  98         inode_item->size = cpu_to_le64(3);
  99         inode_item->nlink = cpu_to_le32(1);
 100         inode_item->nblocks = cpu_to_le64(1);
 101         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 102
 103         btrfs_set_root_bytenr(&root_item, leaf->start);
 104         btrfs_set_root_level(&root_item, 0);
 105         btrfs_set_root_refs(&root_item, 1);
 106         btrfs_set_root_used(&root_item, 0);
 107
 108         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 109         root_item.drop_level = 0;
 110
 111         btrfs_tree_unlock(leaf);
 112         free_extent_buffer(leaf);
 113         leaf = NULL;
 114
 115         btrfs_set_root_dirid(&root_item, new_dirid);
 116
 117         key.objectid = objectid;
 118         key.offset = 1;
 119         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 120         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 121                                 &root_item);
 122         if (ret)
 123                 goto fail;
 124
 125         /*
 126          * insert the directory item
 127          */
 128         key.offset = (u64)-1;
 129         dir = root->fs_info->sb->s_root->d_inode;
 130         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 131                                     name, namelen, dir->i_ino, &key,
 132                                     BTRFS_FT_DIR);
 133         if (ret)
 134                 goto fail;
 135
 136         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
 137                              name, namelen, objectid,
 138                              root->fs_info->sb->s_root->d_inode->i_ino);
 139         if (ret)
 140                 goto fail;
 141
 142         ret = btrfs_commit_transaction(trans, root);
 143         if (ret)
 144                 goto fail_commit;
 145
 146         new_root = btrfs_read_fs_root(root->fs_info, &key, name, namelen);
 147         BUG_ON(!new_root);
 148
 149         trans = btrfs_start_transaction(new_root, 1);
 150         BUG_ON(!trans);
 151
 152         ret = btrfs_create_subvol_root(new_root, trans, new_dirid,
 153                                        BTRFS_I(dir)->block_group);
 154         if (ret)
 155                 goto fail;
 156
 157         /* Invalidate existing dcache entry for new subvolume. */
 158         btrfs_invalidate_dcache_root(root, name, namelen);
 159
 160 fail:
 161         nr = trans->blocks_used;
 162         err = btrfs_commit_transaction(trans, new_root);
 163         if (err && !ret)
 164                 ret = err;
 165 fail_commit:
 166         btrfs_btree_balance_dirty(root, nr);
 167         return ret;
 168 }
 169
 170 static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 171 {
 172         struct btrfs_pending_snapshot *pending_snapshot;
 173         struct btrfs_trans_handle *trans;
 174         int ret;
 175         int err;
 176         unsigned long nr = 0;
 177
 178         if (!root->ref_cows)
 179                 return -EINVAL;
 180
 181         ret = btrfs_check_free_space(root, 1, 0);
 182         if (ret)
 183                 goto fail_unlock;
 184
 185         pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
 186         if (!pending_snapshot) {
 187                 ret = -ENOMEM;
 188                 goto fail_unlock;
 189         }
 190         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
 191         if (!pending_snapshot->name) {
 192                 ret = -ENOMEM;
 193                 kfree(pending_snapshot);
 194                 goto fail_unlock;
 195         }
 196         memcpy(pending_snapshot->name, name, namelen);
 197         pending_snapshot->name[namelen] = '\0';
 198         trans = btrfs_start_transaction(root, 1);
 199         BUG_ON(!trans);
 200         pending_snapshot->root = root;
 201         list_add(&pending_snapshot->list,
 202                  &trans->transaction->pending_snapshots);
 203         ret = btrfs_update_inode(trans, root, root->inode);
 204         err = btrfs_commit_transaction(trans, root);
 205
 206 fail_unlock:
 207         btrfs_btree_balance_dirty(root, nr);
 208         return ret;
 209 }
 210
 211 int btrfs_defrag_file(struct file *file)
 212 {
 213         struct inode *inode = fdentry(file)->d_inode;
 214         struct btrfs_root *root = BTRFS_I(inode)->root;
 215         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 216         struct btrfs_ordered_extent *ordered;
 217         struct page *page;
 218         unsigned long last_index;
 219         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 220         unsigned long total_read = 0;
 221         u64 page_start;
 222         u64 page_end;
 223         unsigned long i;
 224         int ret;
 225
 226         ret = btrfs_check_free_space(root, inode->i_size, 0);
 227         if (ret)
 228                 return -ENOSPC;
 229
 230         mutex_lock(&inode->i_mutex);
 231         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 232         for (i = 0; i <= last_index; i++) {
 233                 if (total_read % ra_pages == 0) {
 234                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 235                                        min(last_index, i + ra_pages - 1));
 236                 }
 237                 total_read++;
 238 again:
 239                 page = grab_cache_page(inode->i_mapping, i);
 240                 if (!page)
 241                         goto out_unlock;
 242                 if (!PageUptodate(page)) {
 243                         btrfs_readpage(NULL, page);
 244                         lock_page(page);
 245                         if (!PageUptodate(page)) {
 246                                 unlock_page(page);
 247                                 page_cache_release(page);
 248                                 goto out_unlock;
 249                         }
 250                 }
 251
 252                 wait_on_page_writeback(page);
 253
 254                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 255                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 256                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 257
 258                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
 259                 if (ordered) {
 260                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 261                         unlock_page(page);
 262                         page_cache_release(page);
 263                         btrfs_start_ordered_extent(inode, ordered, 1);
 264                         btrfs_put_ordered_extent(ordered);
 265                         goto again;
 266                 }
 267                 set_page_extent_mapped(page);
 268
 269                 set_extent_delalloc(io_tree, page_start,
 270                                     page_end, GFP_NOFS);
 271
 272                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 273                 set_page_dirty(page);
 274                 unlock_page(page);
 275                 page_cache_release(page);
 276                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 277         }
 278
 279 out_unlock:
 280         mutex_unlock(&inode->i_mutex);
 281         return 0;
 282 }
 283
 284 /*
 285  * Called inside transaction, so use GFP_NOFS
 286  */
 287
 288 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 289 {
 290         u64 new_size;
 291         u64 old_size;
 292         u64 devid = 1;
 293         struct btrfs_ioctl_vol_args *vol_args;
 294         struct btrfs_trans_handle *trans;
 295         struct btrfs_device *device = NULL;
 296         char *sizestr;
 297         char *devstr = NULL;
 298         int ret = 0;
 299         int namelen;
 300         int mod = 0;
 301
 302         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 303
 304         if (!vol_args)
 305                 return -ENOMEM;
 306
 307         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 308                 ret = -EFAULT;
 309                 goto out;
 310         }
 311         namelen = strlen(vol_args->name);
 312         if (namelen > BTRFS_VOL_NAME_MAX) {
 313                 ret = -EINVAL;
 314                 goto out;
 315         }
 316
 317         mutex_lock(&root->fs_info->volume_mutex);
 318         sizestr = vol_args->name;
 319         devstr = strchr(sizestr, ':');
 320         if (devstr) {
 321                 char *end;
 322                 sizestr = devstr + 1;
 323                 *devstr = '\0';
 324                 devstr = vol_args->name;
 325                 devid = simple_strtoull(devstr, &end, 10);
 326                 printk(KERN_INFO "resizing devid %llu\n", devid);
 327         }
 328         device = btrfs_find_device(root, devid, NULL);
 329         if (!device) {
 330                 printk(KERN_INFO "resizer unable to find device %llu\n", devid);
 331                 ret = -EINVAL;
 332                 goto out_unlock;
 333         }
 334         if (!strcmp(sizestr, "max"))
 335                 new_size = device->bdev->bd_inode->i_size;
 336         else {
 337                 if (sizestr[0] == '-') {
 338                         mod = -1;
 339                         sizestr++;
 340                 } else if (sizestr[0] == '+') {
 341                         mod = 1;
 342                         sizestr++;
 343                 }
 344                 new_size = btrfs_parse_size(sizestr);
 345                 if (new_size == 0) {
 346                         ret = -EINVAL;
 347                         goto out_unlock;
 348                 }
 349         }
 350
 351         old_size = device->total_bytes;
 352
 353         if (mod < 0) {
 354                 if (new_size > old_size) {
 355                         ret = -EINVAL;
 356                         goto out_unlock;
 357                 }
 358                 new_size = old_size - new_size;
 359         } else if (mod > 0) {
 360                 new_size = old_size + new_size;
 361         }
 362
 363         if (new_size < 256 * 1024 * 1024) {
 364                 ret = -EINVAL;
 365                 goto out_unlock;
 366         }
 367         if (new_size > device->bdev->bd_inode->i_size) {
 368                 ret = -EFBIG;
 369                 goto out_unlock;
 370         }
 371
 372         do_div(new_size, root->sectorsize);
 373         new_size *= root->sectorsize;
 374
 375         printk(KERN_INFO "new size for %s is %llu\n",
 376                 device->name, (unsigned long long)new_size);
 377
 378         if (new_size > old_size) {
 379                 trans = btrfs_start_transaction(root, 1);
 380                 ret = btrfs_grow_device(trans, device, new_size);
 381                 btrfs_commit_transaction(trans, root);
 382         } else {
 383                 ret = btrfs_shrink_device(device, new_size);
 384         }
 385
 386 out_unlock:
 387         mutex_unlock(&root->fs_info->volume_mutex);
 388 out:
 389         kfree(vol_args);
 390         return ret;
 391 }
 392
 393 static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
 394                                             void __user *arg)
 395 {
 396         struct btrfs_ioctl_vol_args *vol_args;
 397         struct btrfs_dir_item *di;
 398         struct btrfs_path *path;
 399         u64 root_dirid;
 400         int namelen;
 401         int ret;
 402
 403         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 404
 405         if (!vol_args)
 406                 return -ENOMEM;
 407
 408         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 409                 ret = -EFAULT;
 410                 goto out;
 411         }
 412
 413         namelen = strlen(vol_args->name);
 414         if (namelen > BTRFS_VOL_NAME_MAX) {
 415                 ret = -EINVAL;
 416                 goto out;
 417         }
 418         if (strchr(vol_args->name, '/')) {
 419                 ret = -EINVAL;
 420                 goto out;
 421         }
 422
 423         path = btrfs_alloc_path();
 424         if (!path) {
 425                 ret = -ENOMEM;
 426                 goto out;
 427         }
 428
 429         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 430         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
 431                             path, root_dirid,
 432                             vol_args->name, namelen, 0);
 433         btrfs_free_path(path);
 434
 435         if (di && !IS_ERR(di)) {
 436                 ret = -EEXIST;
 437                 goto out;
 438         }
 439
 440         if (IS_ERR(di)) {
 441                 ret = PTR_ERR(di);
 442                 goto out;
 443         }
 444
 445         mutex_lock(&root->fs_info->drop_mutex);
 446         if (root == root->fs_info->tree_root)
 447                 ret = create_subvol(root, vol_args->name, namelen);
 448         else
 449                 ret = create_snapshot(root, vol_args->name, namelen);
 450         mutex_unlock(&root->fs_info->drop_mutex);
 451 out:
 452         kfree(vol_args);
 453         return ret;
 454 }
 455
 456 static int btrfs_ioctl_defrag(struct file *file)
 457 {
 458         struct inode *inode = fdentry(file)->d_inode;
 459         struct btrfs_root *root = BTRFS_I(inode)->root;
 460
 461         switch (inode->i_mode & S_IFMT) {
 462         case S_IFDIR:
 463                 btrfs_defrag_root(root, 0);
 464                 btrfs_defrag_root(root->fs_info->extent_root, 0);
 465                 break;
 466         case S_IFREG:
 467                 btrfs_defrag_file(file);
 468                 break;
 469         }
 470
 471         return 0;
 472 }
 473
 474 long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 475 {
 476         struct btrfs_ioctl_vol_args *vol_args;
 477         int ret;
 478
 479         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 480
 481         if (!vol_args)
 482                 return -ENOMEM;
 483
 484         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 485                 ret = -EFAULT;
 486                 goto out;
 487         }
 488         ret = btrfs_init_new_device(root, vol_args->name);
 489
 490 out:
 491         kfree(vol_args);
 492         return ret;
 493 }
 494
 495 long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 496 {
 497         struct btrfs_ioctl_vol_args *vol_args;
 498         int ret;
 499
 500         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 501
 502         if (!vol_args)
 503                 return -ENOMEM;
 504
 505         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 506                 ret = -EFAULT;
 507                 goto out;
 508         }
 509         ret = btrfs_rm_device(root, vol_args->name);
 510
 511 out:
 512         kfree(vol_args);
 513         return ret;
 514 }
 515
 516 int dup_item_to_inode(struct btrfs_trans_handle *trans,
 517                        struct btrfs_root *root,
 518                        struct btrfs_path *path,
 519                        struct extent_buffer *leaf,
 520                        int slot,
 521                        struct btrfs_key *key,
 522                        u64 destino)
 523 {
 524         char *dup;
 525         int len = btrfs_item_size_nr(leaf, slot);
 526         struct btrfs_key ckey = *key;
 527         int ret = 0;
 528
 529         dup = kmalloc(len, GFP_NOFS);
 530         if (!dup)
 531                 return -ENOMEM;
 532
 533         read_extent_buffer(leaf, dup, btrfs_item_ptr_offset(leaf, slot), len);
 534         btrfs_release_path(root, path);
 535
 536         ckey.objectid = destino;
 537         ret = btrfs_insert_item(trans, root, &ckey, dup, len);
 538         kfree(dup);
 539         return ret;
 540 }
 541
 542 long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
 543 {
 544         struct inode *inode = fdentry(file)->d_inode;
 545         struct btrfs_root *root = BTRFS_I(inode)->root;
 546         struct file *src_file;
 547         struct inode *src;
 548         struct btrfs_trans_handle *trans;
 549         int ret;
 550         u64 pos;
 551         struct btrfs_path *path;
 552         struct btrfs_key key;
 553         struct extent_buffer *leaf;
 554         u32 nritems;
 555         int slot;
 556
 557         src_file = fget(src_fd);
 558         if (!src_file)
 559                 return -EBADF;
 560         src = src_file->f_dentry->d_inode;
 561
 562         ret = -EXDEV;
 563         if (src->i_sb != inode->i_sb)
 564                 goto out_fput;
 565
 566         if (inode < src) {
 567                 mutex_lock(&inode->i_mutex);
 568                 mutex_lock(&src->i_mutex);
 569         } else {
 570                 mutex_lock(&src->i_mutex);
 571                 mutex_lock(&inode->i_mutex);
 572         }
 573
 574         ret = -ENOTEMPTY;
 575         if (inode->i_size)
 576                 goto out_unlock;
 577
 578         /* do any pending delalloc/csum calc on src, one way or
 579            another, and lock file content */
 580         while (1) {
 581                 filemap_write_and_wait(src->i_mapping);
 582                 lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 583                 if (BTRFS_I(src)->delalloc_bytes == 0)
 584                         break;
 585                 unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 586         }
 587
 588         trans = btrfs_start_transaction(root, 0);
 589         path = btrfs_alloc_path();
 590         if (!path) {
 591                 ret = -ENOMEM;
 592                 goto out;
 593         }
 594         key.offset = 0;
 595         key.type = BTRFS_EXTENT_DATA_KEY;
 596         key.objectid = src->i_ino;
 597         pos = 0;
 598         path->reada = 2;
 599
 600         while (1) {
 601                 /*
 602                  * note the key will change type as we walk through the
 603                  * tree.
 604                  */
 605                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 606                 if (ret < 0)
 607                         goto out;
 608
 609                 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
 610                         ret = btrfs_next_leaf(root, path);
 611                         if (ret < 0)
 612                                 goto out;
 613                         if (ret > 0)
 614                                 break;
 615                 }
 616                 leaf = path->nodes[0];
 617                 slot = path->slots[0];
 618                 btrfs_item_key_to_cpu(leaf, &key, slot);
 619                 nritems = btrfs_header_nritems(leaf);
 620
 621                 if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
 622                     key.objectid != src->i_ino)
 623                         break;
 624
 625                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 626                         struct btrfs_file_extent_item *extent;
 627                         int found_type;
 628                         pos = key.offset;
 629                         extent = btrfs_item_ptr(leaf, slot,
 630                                                 struct btrfs_file_extent_item);
 631                         found_type = btrfs_file_extent_type(leaf, extent);
 632                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 633                                 u64 len = btrfs_file_extent_num_bytes(leaf,
 634                                                                       extent);
 635                                 u64 ds = btrfs_file_extent_disk_bytenr(leaf,
 636                                                                        extent);
 637                                 u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
 638                                                                  extent);
 639                                 u64 off = btrfs_file_extent_offset(leaf,
 640                                                                    extent);
 641                                 btrfs_insert_file_extent(trans, root,
 642                                                          inode->i_ino, pos,
 643                                                          ds, dl, len, off);
 644                                 /* ds == 0 means there's a hole */
 645                                 if (ds != 0) {
 646                                         btrfs_inc_extent_ref(trans, root,
 647                                                      ds, dl,
 648                                                      root->root_key.objectid,
 649                                                      trans->transid,
 650                                                      inode->i_ino, pos);
 651                                 }
 652                                 pos = key.offset + len;
 653                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 654                                 ret = dup_item_to_inode(trans, root, path,
 655                                                         leaf, slot, &key,
 656                                                         inode->i_ino);
 657                                 if (ret)
 658                                         goto out;
 659                                 pos = key.offset + btrfs_item_size_nr(leaf,
 660                                                                       slot);
 661                         }
 662                 } else if (btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
 663                         ret = dup_item_to_inode(trans, root, path, leaf,
 664                                                 slot, &key, inode->i_ino);
 665
 666                         if (ret)
 667                                 goto out;
 668                 }
 669                 key.offset++;
 670                 btrfs_release_path(root, path);
 671         }
 672
 673         ret = 0;
 674 out:
 675         btrfs_free_path(path);
 676
 677         inode->i_blocks = src->i_blocks;
 678         i_size_write(inode, src->i_size);
 679         btrfs_update_inode(trans, root, inode);
 680
 681         unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 682
 683         btrfs_end_transaction(trans, root);
 684
 685 out_unlock:
 686         mutex_unlock(&src->i_mutex);
 687         mutex_unlock(&inode->i_mutex);
 688 out_fput:
 689         fput(src_file);
 690         return ret;
 691 }
 692
 693 /*
 694  * there are many ways the trans_start and trans_end ioctls can lead
 695  * to deadlocks.  They should only be used by applications that
 696  * basically own the machine, and have a very in depth understanding
 697  * of all the possible deadlocks and enospc problems.
 698  */
 699 long btrfs_ioctl_trans_start(struct file *file)
 700 {
 701         struct inode *inode = fdentry(file)->d_inode;
 702         struct btrfs_root *root = BTRFS_I(inode)->root;
 703         struct btrfs_trans_handle *trans;
 704         int ret = 0;
 705
 706         if (!capable(CAP_SYS_ADMIN))
 707                 return -EPERM;
 708
 709         if (file->private_data) {
 710                 ret = -EINPROGRESS;
 711                 goto out;
 712         }
 713         trans = btrfs_start_transaction(root, 0);
 714         if (trans)
 715                 file->private_data = trans;
 716         else
 717                 ret = -ENOMEM;
 718         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
 719 out:
 720         return ret;
 721 }
 722
 723 /*
 724  * there are many ways the trans_start and trans_end ioctls can lead
 725  * to deadlocks.  They should only be used by applications that
 726  * basically own the machine, and have a very in depth understanding
 727  * of all the possible deadlocks and enospc problems.
 728  */
 729 long btrfs_ioctl_trans_end(struct file *file)
 730 {
 731         struct inode *inode = fdentry(file)->d_inode;
 732         struct btrfs_root *root = BTRFS_I(inode)->root;
 733         struct btrfs_trans_handle *trans;
 734         int ret = 0;
 735
 736         trans = file->private_data;
 737         if (!trans) {
 738                 ret = -EINVAL;
 739                 goto out;
 740         }
 741         btrfs_end_transaction(trans, root);
 742         file->private_data = 0;
 743 out:
 744         return ret;
 745 }
 746
 747 long btrfs_ioctl(struct file *file, unsigned int
 748                 cmd, unsigned long arg)
 749 {
 750         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 751
 752         switch (cmd) {
 753         case BTRFS_IOC_SNAP_CREATE:
 754                 return btrfs_ioctl_snap_create(root, (void __user *)arg);
 755         case BTRFS_IOC_DEFRAG:
 756                 return btrfs_ioctl_defrag(file);
 757         case BTRFS_IOC_RESIZE:
 758                 return btrfs_ioctl_resize(root, (void __user *)arg);
 759         case BTRFS_IOC_ADD_DEV:
 760                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
 761         case BTRFS_IOC_RM_DEV:
 762                 return btrfs_ioctl_rm_dev(root, (void __user *)arg);
 763         case BTRFS_IOC_BALANCE:
 764                 return btrfs_balance(root->fs_info->dev_root);
 765         case BTRFS_IOC_CLONE:
 766                 return btrfs_ioctl_clone(file, arg);
 767         case BTRFS_IOC_TRANS_START:
 768                 return btrfs_ioctl_trans_start(file);
 769         case BTRFS_IOC_TRANS_END:
 770                 return btrfs_ioctl_trans_end(file);
 771         case BTRFS_IOC_SYNC:
 772                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
 773                 return 0;
 774         }
 775
 776         return -ENOTTY;
 777 }