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         btrfs_throttle(root);
 168         return ret;
 169 }
 170
 171 static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 172 {
 173         struct btrfs_pending_snapshot *pending_snapshot;
 174         struct btrfs_trans_handle *trans;
 175         int ret;
 176         int err;
 177         unsigned long nr = 0;
 178
 179         if (!root->ref_cows)
 180                 return -EINVAL;
 181
 182         ret = btrfs_check_free_space(root, 1, 0);
 183         if (ret)
 184                 goto fail_unlock;
 185
 186         pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
 187         if (!pending_snapshot) {
 188                 ret = -ENOMEM;
 189                 goto fail_unlock;
 190         }
 191         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
 192         if (!pending_snapshot->name) {
 193                 ret = -ENOMEM;
 194                 kfree(pending_snapshot);
 195                 goto fail_unlock;
 196         }
 197         memcpy(pending_snapshot->name, name, namelen);
 198         pending_snapshot->name[namelen] = '\0';
 199         trans = btrfs_start_transaction(root, 1);
 200         BUG_ON(!trans);
 201         pending_snapshot->root = root;
 202         list_add(&pending_snapshot->list,
 203                  &trans->transaction->pending_snapshots);
 204         ret = btrfs_update_inode(trans, root, root->inode);
 205         err = btrfs_commit_transaction(trans, root);
 206
 207 fail_unlock:
 208         btrfs_btree_balance_dirty(root, nr);
 209         btrfs_throttle(root);
 210         return ret;
 211 }
 212
 213 int btrfs_defrag_file(struct file *file)
 214 {
 215         struct inode *inode = fdentry(file)->d_inode;
 216         struct btrfs_root *root = BTRFS_I(inode)->root;
 217         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 218         struct page *page;
 219         unsigned long last_index;
 220         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 221         unsigned long total_read = 0;
 222         u64 page_start;
 223         u64 page_end;
 224         unsigned long i;
 225         int ret;
 226
 227         ret = btrfs_check_free_space(root, inode->i_size, 0);
 228         if (ret)
 229                 return -ENOSPC;
 230
 231         mutex_lock(&inode->i_mutex);
 232         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 233         for (i = 0; i <= last_index; i++) {
 234                 if (total_read % ra_pages == 0) {
 235                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 236                                        min(last_index, i + ra_pages - 1));
 237                 }
 238                 total_read++;
 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 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 253                 ClearPageDirty(page);
 254 #else
 255                 cancel_dirty_page(page, PAGE_CACHE_SIZE);
 256 #endif
 257                 wait_on_page_writeback(page);
 258                 set_page_extent_mapped(page);
 259
 260                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 261                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 262
 263                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 264                 set_extent_delalloc(io_tree, page_start,
 265                                     page_end, GFP_NOFS);
 266
 267                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 268                 set_page_dirty(page);
 269                 unlock_page(page);
 270                 page_cache_release(page);
 271                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 272         }
 273
 274 out_unlock:
 275         mutex_unlock(&inode->i_mutex);
 276         return 0;
 277 }
 278
 279 /*
 280  * Called inside transaction, so use GFP_NOFS
 281  */
 282
 283 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 284 {
 285         u64 new_size;
 286         u64 old_size;
 287         u64 devid = 1;
 288         struct btrfs_ioctl_vol_args *vol_args;
 289         struct btrfs_trans_handle *trans;
 290         struct btrfs_device *device = NULL;
 291         char *sizestr;
 292         char *devstr = NULL;
 293         int ret = 0;
 294         int namelen;
 295         int mod = 0;
 296
 297         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 298
 299         if (!vol_args)
 300                 return -ENOMEM;
 301
 302         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 303                 ret = -EFAULT;
 304                 goto out;
 305         }
 306         namelen = strlen(vol_args->name);
 307         if (namelen > BTRFS_VOL_NAME_MAX) {
 308                 ret = -EINVAL;
 309                 goto out;
 310         }
 311
 312         mutex_lock(&root->fs_info->alloc_mutex);
 313         mutex_lock(&root->fs_info->chunk_mutex);
 314         sizestr = vol_args->name;
 315         devstr = strchr(sizestr, ':');
 316         if (devstr) {
 317                 char *end;
 318                 sizestr = devstr + 1;
 319                 *devstr = '\0';
 320                 devstr = vol_args->name;
 321                 devid = simple_strtoull(devstr, &end, 10);
 322                 printk(KERN_INFO "resizing devid %llu\n", devid);
 323         }
 324         device = btrfs_find_device(root, devid, NULL);
 325         if (!device) {
 326                 printk(KERN_INFO "resizer unable to find device %llu\n", devid);
 327                 ret = -EINVAL;
 328                 goto out_unlock;
 329         }
 330         if (!strcmp(sizestr, "max"))
 331                 new_size = device->bdev->bd_inode->i_size;
 332         else {
 333                 if (sizestr[0] == '-') {
 334                         mod = -1;
 335                         sizestr++;
 336                 } else if (sizestr[0] == '+') {
 337                         mod = 1;
 338                         sizestr++;
 339                 }
 340                 new_size = btrfs_parse_size(sizestr);
 341                 if (new_size == 0) {
 342                         ret = -EINVAL;
 343                         goto out_unlock;
 344                 }
 345         }
 346
 347         old_size = device->total_bytes;
 348
 349         if (mod < 0) {
 350                 if (new_size > old_size) {
 351                         ret = -EINVAL;
 352                         goto out_unlock;
 353                 }
 354                 new_size = old_size - new_size;
 355         } else if (mod > 0) {
 356                 new_size = old_size + new_size;
 357         }
 358
 359         if (new_size < 256 * 1024 * 1024) {
 360                 ret = -EINVAL;
 361                 goto out_unlock;
 362         }
 363         if (new_size > device->bdev->bd_inode->i_size) {
 364                 ret = -EFBIG;
 365                 goto out_unlock;
 366         }
 367
 368         do_div(new_size, root->sectorsize);
 369         new_size *= root->sectorsize;
 370
 371         printk(KERN_INFO "new size for %s is %llu\n",
 372                 device->name, (unsigned long long)new_size);
 373
 374         if (new_size > old_size) {
 375                 trans = btrfs_start_transaction(root, 1);
 376                 ret = btrfs_grow_device(trans, device, new_size);
 377                 btrfs_commit_transaction(trans, root);
 378         } else {
 379                 ret = btrfs_shrink_device(device, new_size);
 380         }
 381
 382 out_unlock:
 383         mutex_lock(&root->fs_info->alloc_mutex);
 384         mutex_lock(&root->fs_info->chunk_mutex);
 385 out:
 386         kfree(vol_args);
 387         return ret;
 388 }
 389
 390 static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
 391                                             void __user *arg)
 392 {
 393         struct btrfs_ioctl_vol_args *vol_args;
 394         struct btrfs_dir_item *di;
 395         struct btrfs_path *path;
 396         u64 root_dirid;
 397         int namelen;
 398         int ret;
 399
 400         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 401
 402         if (!vol_args)
 403                 return -ENOMEM;
 404
 405         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 406                 ret = -EFAULT;
 407                 goto out;
 408         }
 409
 410         namelen = strlen(vol_args->name);
 411         if (namelen > BTRFS_VOL_NAME_MAX) {
 412                 ret = -EINVAL;
 413                 goto out;
 414         }
 415         if (strchr(vol_args->name, '/')) {
 416                 ret = -EINVAL;
 417                 goto out;
 418         }
 419
 420         path = btrfs_alloc_path();
 421         if (!path) {
 422                 ret = -ENOMEM;
 423                 goto out;
 424         }
 425
 426         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 427         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
 428                             path, root_dirid,
 429                             vol_args->name, namelen, 0);
 430         btrfs_free_path(path);
 431
 432         if (di && !IS_ERR(di)) {
 433                 ret = -EEXIST;
 434                 goto out;
 435         }
 436
 437         if (IS_ERR(di)) {
 438                 ret = PTR_ERR(di);
 439                 goto out;
 440         }
 441
 442         mutex_lock(&root->fs_info->drop_mutex);
 443         if (root == root->fs_info->tree_root)
 444                 ret = create_subvol(root, vol_args->name, namelen);
 445         else
 446                 ret = create_snapshot(root, vol_args->name, namelen);
 447         mutex_unlock(&root->fs_info->drop_mutex);
 448 out:
 449         kfree(vol_args);
 450         return ret;
 451 }
 452
 453 static int btrfs_ioctl_defrag(struct file *file)
 454 {
 455         struct inode *inode = fdentry(file)->d_inode;
 456         struct btrfs_root *root = BTRFS_I(inode)->root;
 457
 458         switch (inode->i_mode & S_IFMT) {
 459         case S_IFDIR:
 460                 btrfs_defrag_root(root, 0);
 461                 btrfs_defrag_root(root->fs_info->extent_root, 0);
 462                 break;
 463         case S_IFREG:
 464                 btrfs_defrag_file(file);
 465                 break;
 466         }
 467
 468         return 0;
 469 }
 470
 471 long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 472 {
 473         struct btrfs_ioctl_vol_args *vol_args;
 474         int ret;
 475
 476         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 477
 478         if (!vol_args)
 479                 return -ENOMEM;
 480
 481         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 482                 ret = -EFAULT;
 483                 goto out;
 484         }
 485         ret = btrfs_init_new_device(root, vol_args->name);
 486
 487 out:
 488         kfree(vol_args);
 489         return ret;
 490 }
 491
 492 long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 493 {
 494         struct btrfs_ioctl_vol_args *vol_args;
 495         int ret;
 496
 497         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 498
 499         if (!vol_args)
 500                 return -ENOMEM;
 501
 502         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 503                 ret = -EFAULT;
 504                 goto out;
 505         }
 506         ret = btrfs_rm_device(root, vol_args->name);
 507
 508 out:
 509         kfree(vol_args);
 510         return ret;
 511 }
 512
 513 int dup_item_to_inode(struct btrfs_trans_handle *trans,
 514                        struct btrfs_root *root,
 515                        struct btrfs_path *path,
 516                        struct extent_buffer *leaf,
 517                        int slot,
 518                        struct btrfs_key *key,
 519                        u64 destino)
 520 {
 521         char *dup;
 522         int len = btrfs_item_size_nr(leaf, slot);
 523         struct btrfs_key ckey = *key;
 524         int ret = 0;
 525
 526         dup = kmalloc(len, GFP_NOFS);
 527         if (!dup)
 528                 return -ENOMEM;
 529
 530         read_extent_buffer(leaf, dup, btrfs_item_ptr_offset(leaf, slot), len);
 531         btrfs_release_path(root, path);
 532
 533         ckey.objectid = destino;
 534         ret = btrfs_insert_item(trans, root, &ckey, dup, len);
 535         kfree(dup);
 536         return ret;
 537 }
 538
 539 long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
 540 {
 541         struct inode *inode = fdentry(file)->d_inode;
 542         struct btrfs_root *root = BTRFS_I(inode)->root;
 543         struct file *src_file;
 544         struct inode *src;
 545         struct btrfs_trans_handle *trans;
 546         int ret;
 547         u64 pos;
 548         struct btrfs_path *path;
 549         struct btrfs_key key;
 550         struct extent_buffer *leaf;
 551         u32 nritems;
 552         int slot;
 553
 554         src_file = fget(src_fd);
 555         if (!src_file)
 556                 return -EBADF;
 557         src = src_file->f_dentry->d_inode;
 558
 559         ret = -EXDEV;
 560         if (src->i_sb != inode->i_sb)
 561                 goto out_fput;
 562
 563         if (inode < src) {
 564                 mutex_lock(&inode->i_mutex);
 565                 mutex_lock(&src->i_mutex);
 566         } else {
 567                 mutex_lock(&src->i_mutex);
 568                 mutex_lock(&inode->i_mutex);
 569         }
 570
 571         ret = -ENOTEMPTY;
 572         if (inode->i_size)
 573                 goto out_unlock;
 574
 575         /* do any pending delalloc/csum calc on src, one way or
 576            another, and lock file content */
 577         while (1) {
 578                 filemap_write_and_wait(src->i_mapping);
 579                 lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 580                 if (BTRFS_I(src)->delalloc_bytes == 0)
 581                         break;
 582                 unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 583         }
 584
 585         trans = btrfs_start_transaction(root, 0);
 586         path = btrfs_alloc_path();
 587         if (!path) {
 588                 ret = -ENOMEM;
 589                 goto out;
 590         }
 591         key.offset = 0;
 592         key.type = BTRFS_EXTENT_DATA_KEY;
 593         key.objectid = src->i_ino;
 594         pos = 0;
 595         path->reada = 2;
 596
 597         while (1) {
 598                 /*
 599                  * note the key will change type as we walk through the
 600                  * tree.
 601                  */
 602                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 603                 if (ret < 0)
 604                         goto out;
 605
 606                 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
 607                         ret = btrfs_next_leaf(root, path);
 608                         if (ret < 0)
 609                                 goto out;
 610                         if (ret > 0)
 611                                 break;
 612                 }
 613                 leaf = path->nodes[0];
 614                 slot = path->slots[0];
 615                 btrfs_item_key_to_cpu(leaf, &key, slot);
 616                 nritems = btrfs_header_nritems(leaf);
 617
 618                 if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
 619                     key.objectid != src->i_ino)
 620                         break;
 621
 622                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 623                         struct btrfs_file_extent_item *extent;
 624                         int found_type;
 625                         pos = key.offset;
 626                         extent = btrfs_item_ptr(leaf, slot,
 627                                                 struct btrfs_file_extent_item);
 628                         found_type = btrfs_file_extent_type(leaf, extent);
 629                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 630                                 u64 len = btrfs_file_extent_num_bytes(leaf,
 631                                                                       extent);
 632                                 u64 ds = btrfs_file_extent_disk_bytenr(leaf,
 633                                                                        extent);
 634                                 u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
 635                                                                  extent);
 636                                 u64 off = btrfs_file_extent_offset(leaf,
 637                                                                    extent);
 638                                 btrfs_insert_file_extent(trans, root,
 639                                                          inode->i_ino, pos,
 640                                                          ds, dl, len, off);
 641                                 /* ds == 0 means there's a hole */
 642                                 if (ds != 0) {
 643                                         btrfs_inc_extent_ref(trans, root,
 644                                                      ds, dl,
 645                                                      root->root_key.objectid,
 646                                                      trans->transid,
 647                                                      inode->i_ino, pos);
 648                                 }
 649                                 pos = key.offset + len;
 650                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 651                                 ret = dup_item_to_inode(trans, root, path,
 652                                                         leaf, slot, &key,
 653                                                         inode->i_ino);
 654                                 if (ret)
 655                                         goto out;
 656                                 pos = key.offset + btrfs_item_size_nr(leaf,
 657                                                                       slot);
 658                         }
 659                 } else if (btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
 660                         ret = dup_item_to_inode(trans, root, path, leaf,
 661                                                 slot, &key, inode->i_ino);
 662
 663                         if (ret)
 664                                 goto out;
 665                 }
 666                 key.offset++;
 667                 btrfs_release_path(root, path);
 668         }
 669
 670         ret = 0;
 671 out:
 672         btrfs_free_path(path);
 673
 674         inode->i_blocks = src->i_blocks;
 675         i_size_write(inode, src->i_size);
 676         btrfs_update_inode(trans, root, inode);
 677
 678         unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 679
 680         btrfs_end_transaction(trans, root);
 681
 682 out_unlock:
 683         mutex_unlock(&src->i_mutex);
 684         mutex_unlock(&inode->i_mutex);
 685 out_fput:
 686         fput(src_file);
 687         return ret;
 688 }
 689
 690 /*
 691  * there are many ways the trans_start and trans_end ioctls can lead
 692  * to deadlocks.  They should only be used by applications that
 693  * basically own the machine, and have a very in depth understanding
 694  * of all the possible deadlocks and enospc problems.
 695  */
 696 long btrfs_ioctl_trans_start(struct file *file)
 697 {
 698         struct inode *inode = fdentry(file)->d_inode;
 699         struct btrfs_root *root = BTRFS_I(inode)->root;
 700         struct btrfs_trans_handle *trans;
 701         int ret = 0;
 702
 703         if (!capable(CAP_SYS_ADMIN))
 704                 return -EPERM;
 705
 706         if (file->private_data) {
 707                 ret = -EINPROGRESS;
 708                 goto out;
 709         }
 710         trans = btrfs_start_transaction(root, 0);
 711         if (trans)
 712                 file->private_data = trans;
 713         else
 714                 ret = -ENOMEM;
 715         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
 716 out:
 717         return ret;
 718 }
 719
 720 /*
 721  * there are many ways the trans_start and trans_end ioctls can lead
 722  * to deadlocks.  They should only be used by applications that
 723  * basically own the machine, and have a very in depth understanding
 724  * of all the possible deadlocks and enospc problems.
 725  */
 726 long btrfs_ioctl_trans_end(struct file *file)
 727 {
 728         struct inode *inode = fdentry(file)->d_inode;
 729         struct btrfs_root *root = BTRFS_I(inode)->root;
 730         struct btrfs_trans_handle *trans;
 731         int ret = 0;
 732
 733         trans = file->private_data;
 734         if (!trans) {
 735                 ret = -EINVAL;
 736                 goto out;
 737         }
 738         btrfs_end_transaction(trans, root);
 739         file->private_data = 0;
 740 out:
 741         return ret;
 742 }
 743
 744 long btrfs_ioctl(struct file *file, unsigned int
 745                 cmd, unsigned long arg)
 746 {
 747         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 748
 749         switch (cmd) {
 750         case BTRFS_IOC_SNAP_CREATE:
 751                 return btrfs_ioctl_snap_create(root, (void __user *)arg);
 752         case BTRFS_IOC_DEFRAG:
 753                 return btrfs_ioctl_defrag(file);
 754         case BTRFS_IOC_RESIZE:
 755                 return btrfs_ioctl_resize(root, (void __user *)arg);
 756         case BTRFS_IOC_ADD_DEV:
 757                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
 758         case BTRFS_IOC_RM_DEV:
 759                 return btrfs_ioctl_rm_dev(root, (void __user *)arg);
 760         case BTRFS_IOC_BALANCE:
 761                 return btrfs_balance(root->fs_info->dev_root);
 762         case BTRFS_IOC_CLONE:
 763                 return btrfs_ioctl_clone(file, arg);
 764         case BTRFS_IOC_TRANS_START:
 765                 return btrfs_ioctl_trans_start(file);
 766         case BTRFS_IOC_TRANS_END:
 767                 return btrfs_ioctl_trans_end(file);
 768         case BTRFS_IOC_SYNC:
 769                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
 770                 return 0;
 771         }
 772
 773         return -ENOTTY;
 774 }