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                 ret = PTR_ERR(leaf);
  83                 goto fail;
  84         }
  85
  86         btrfs_set_header_nritems(leaf, 0);
  87         btrfs_set_header_level(leaf, 0);
  88         btrfs_set_header_bytenr(leaf, leaf->start);
  89         btrfs_set_header_generation(leaf, trans->transid);
  90         btrfs_set_header_owner(leaf, objectid);
  91
  92         write_extent_buffer(leaf, root->fs_info->fsid,
  93                             (unsigned long)btrfs_header_fsid(leaf),
  94                             BTRFS_FSID_SIZE);
  95         btrfs_mark_buffer_dirty(leaf);
  96
  97         inode_item = &root_item.inode;
  98         memset(inode_item, 0, sizeof(*inode_item));
  99         inode_item->generation = cpu_to_le64(1);
 100         inode_item->size = cpu_to_le64(3);
 101         inode_item->nlink = cpu_to_le32(1);
 102         inode_item->nblocks = cpu_to_le64(1);
 103         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 104
 105         btrfs_set_root_bytenr(&root_item, leaf->start);
 106         btrfs_set_root_level(&root_item, 0);
 107         btrfs_set_root_refs(&root_item, 1);
 108         btrfs_set_root_used(&root_item, 0);
 109
 110         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 111         root_item.drop_level = 0;
 112
 113         btrfs_tree_unlock(leaf);
 114         free_extent_buffer(leaf);
 115         leaf = NULL;
 116
 117         btrfs_set_root_dirid(&root_item, new_dirid);
 118
 119         key.objectid = objectid;
 120         key.offset = 1;
 121         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 122         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 123                                 &root_item);
 124         if (ret)
 125                 goto fail;
 126
 127         /*
 128          * insert the directory item
 129          */
 130         key.offset = (u64)-1;
 131         dir = root->fs_info->sb->s_root->d_inode;
 132         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 133                                     name, namelen, dir->i_ino, &key,
 134                                     BTRFS_FT_DIR, 0);
 135         if (ret)
 136                 goto fail;
 137
 138         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
 139                              name, namelen, objectid,
 140                              root->fs_info->sb->s_root->d_inode->i_ino, 0);
 141         if (ret)
 142                 goto fail;
 143
 144         ret = btrfs_commit_transaction(trans, root);
 145         if (ret)
 146                 goto fail_commit;
 147
 148         new_root = btrfs_read_fs_root(root->fs_info, &key, name, namelen);
 149         BUG_ON(!new_root);
 150
 151         trans = btrfs_start_transaction(new_root, 1);
 152         BUG_ON(!trans);
 153
 154         ret = btrfs_create_subvol_root(new_root, trans, new_dirid,
 155                                        BTRFS_I(dir)->block_group);
 156         if (ret)
 157                 goto fail;
 158
 159         /* Invalidate existing dcache entry for new subvolume. */
 160         btrfs_invalidate_dcache_root(root, name, namelen);
 161
 162 fail:
 163         nr = trans->blocks_used;
 164         err = btrfs_commit_transaction(trans, new_root);
 165         if (err && !ret)
 166                 ret = err;
 167 fail_commit:
 168         btrfs_btree_balance_dirty(root, nr);
 169         return ret;
 170 }
 171
 172 static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 173 {
 174         struct btrfs_pending_snapshot *pending_snapshot;
 175         struct btrfs_trans_handle *trans;
 176         int ret;
 177         int err;
 178         unsigned long nr = 0;
 179
 180         if (!root->ref_cows)
 181                 return -EINVAL;
 182
 183         ret = btrfs_check_free_space(root, 1, 0);
 184         if (ret)
 185                 goto fail_unlock;
 186
 187         pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
 188         if (!pending_snapshot) {
 189                 ret = -ENOMEM;
 190                 goto fail_unlock;
 191         }
 192         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
 193         if (!pending_snapshot->name) {
 194                 ret = -ENOMEM;
 195                 kfree(pending_snapshot);
 196                 goto fail_unlock;
 197         }
 198         memcpy(pending_snapshot->name, name, namelen);
 199         pending_snapshot->name[namelen] = '\0';
 200         trans = btrfs_start_transaction(root, 1);
 201         BUG_ON(!trans);
 202         pending_snapshot->root = root;
 203         list_add(&pending_snapshot->list,
 204                  &trans->transaction->pending_snapshots);
 205         ret = btrfs_update_inode(trans, root, root->inode);
 206         err = btrfs_commit_transaction(trans, root);
 207
 208 fail_unlock:
 209         btrfs_btree_balance_dirty(root, nr);
 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 btrfs_ordered_extent *ordered;
 219         struct page *page;
 220         unsigned long last_index;
 221         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 222         unsigned long total_read = 0;
 223         u64 page_start;
 224         u64 page_end;
 225         unsigned long i;
 226         int ret;
 227
 228         ret = btrfs_check_free_space(root, inode->i_size, 0);
 229         if (ret)
 230                 return -ENOSPC;
 231
 232         mutex_lock(&inode->i_mutex);
 233         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 234         for (i = 0; i <= last_index; i++) {
 235                 if (total_read % ra_pages == 0) {
 236                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 237                                        min(last_index, i + ra_pages - 1));
 238                 }
 239                 total_read++;
 240 again:
 241                 page = grab_cache_page(inode->i_mapping, i);
 242                 if (!page)
 243                         goto out_unlock;
 244                 if (!PageUptodate(page)) {
 245                         btrfs_readpage(NULL, page);
 246                         lock_page(page);
 247                         if (!PageUptodate(page)) {
 248                                 unlock_page(page);
 249                                 page_cache_release(page);
 250                                 goto out_unlock;
 251                         }
 252                 }
 253
 254                 wait_on_page_writeback(page);
 255
 256                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 257                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 258                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 259
 260                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
 261                 if (ordered) {
 262                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 263                         unlock_page(page);
 264                         page_cache_release(page);
 265                         btrfs_start_ordered_extent(inode, ordered, 1);
 266                         btrfs_put_ordered_extent(ordered);
 267                         goto again;
 268                 }
 269                 set_page_extent_mapped(page);
 270
 271                 set_extent_delalloc(io_tree, page_start,
 272                                     page_end, GFP_NOFS);
 273
 274                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 275                 set_page_dirty(page);
 276                 unlock_page(page);
 277                 page_cache_release(page);
 278                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 279         }
 280
 281 out_unlock:
 282         mutex_unlock(&inode->i_mutex);
 283         return 0;
 284 }
 285
 286 /*
 287  * Called inside transaction, so use GFP_NOFS
 288  */
 289
 290 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 291 {
 292         u64 new_size;
 293         u64 old_size;
 294         u64 devid = 1;
 295         struct btrfs_ioctl_vol_args *vol_args;
 296         struct btrfs_trans_handle *trans;
 297         struct btrfs_device *device = NULL;
 298         char *sizestr;
 299         char *devstr = NULL;
 300         int ret = 0;
 301         int namelen;
 302         int mod = 0;
 303
 304         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 305
 306         if (!vol_args)
 307                 return -ENOMEM;
 308
 309         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 310                 ret = -EFAULT;
 311                 goto out;
 312         }
 313         namelen = strlen(vol_args->name);
 314         if (namelen > BTRFS_VOL_NAME_MAX) {
 315                 ret = -EINVAL;
 316                 goto out;
 317         }
 318
 319         mutex_lock(&root->fs_info->volume_mutex);
 320         sizestr = vol_args->name;
 321         devstr = strchr(sizestr, ':');
 322         if (devstr) {
 323                 char *end;
 324                 sizestr = devstr + 1;
 325                 *devstr = '\0';
 326                 devstr = vol_args->name;
 327                 devid = simple_strtoull(devstr, &end, 10);
 328                 printk(KERN_INFO "resizing devid %llu\n", devid);
 329         }
 330         device = btrfs_find_device(root, devid, NULL);
 331         if (!device) {
 332                 printk(KERN_INFO "resizer unable to find device %llu\n", devid);
 333                 ret = -EINVAL;
 334                 goto out_unlock;
 335         }
 336         if (!strcmp(sizestr, "max"))
 337                 new_size = device->bdev->bd_inode->i_size;
 338         else {
 339                 if (sizestr[0] == '-') {
 340                         mod = -1;
 341                         sizestr++;
 342                 } else if (sizestr[0] == '+') {
 343                         mod = 1;
 344                         sizestr++;
 345                 }
 346                 new_size = btrfs_parse_size(sizestr);
 347                 if (new_size == 0) {
 348                         ret = -EINVAL;
 349                         goto out_unlock;
 350                 }
 351         }
 352
 353         old_size = device->total_bytes;
 354
 355         if (mod < 0) {
 356                 if (new_size > old_size) {
 357                         ret = -EINVAL;
 358                         goto out_unlock;
 359                 }
 360                 new_size = old_size - new_size;
 361         } else if (mod > 0) {
 362                 new_size = old_size + new_size;
 363         }
 364
 365         if (new_size < 256 * 1024 * 1024) {
 366                 ret = -EINVAL;
 367                 goto out_unlock;
 368         }
 369         if (new_size > device->bdev->bd_inode->i_size) {
 370                 ret = -EFBIG;
 371                 goto out_unlock;
 372         }
 373
 374         do_div(new_size, root->sectorsize);
 375         new_size *= root->sectorsize;
 376
 377         printk(KERN_INFO "new size for %s is %llu\n",
 378                 device->name, (unsigned long long)new_size);
 379
 380         if (new_size > old_size) {
 381                 trans = btrfs_start_transaction(root, 1);
 382                 ret = btrfs_grow_device(trans, device, new_size);
 383                 btrfs_commit_transaction(trans, root);
 384         } else {
 385                 ret = btrfs_shrink_device(device, new_size);
 386         }
 387
 388 out_unlock:
 389         mutex_unlock(&root->fs_info->volume_mutex);
 390 out:
 391         kfree(vol_args);
 392         return ret;
 393 }
 394
 395 static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
 396                                             void __user *arg)
 397 {
 398         struct btrfs_ioctl_vol_args *vol_args;
 399         struct btrfs_dir_item *di;
 400         struct btrfs_path *path;
 401         u64 root_dirid;
 402         int namelen;
 403         int ret;
 404
 405         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 406
 407         if (!vol_args)
 408                 return -ENOMEM;
 409
 410         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 411                 ret = -EFAULT;
 412                 goto out;
 413         }
 414
 415         namelen = strlen(vol_args->name);
 416         if (namelen > BTRFS_VOL_NAME_MAX) {
 417                 ret = -EINVAL;
 418                 goto out;
 419         }
 420         if (strchr(vol_args->name, '/')) {
 421                 ret = -EINVAL;
 422                 goto out;
 423         }
 424
 425         path = btrfs_alloc_path();
 426         if (!path) {
 427                 ret = -ENOMEM;
 428                 goto out;
 429         }
 430
 431         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 432         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
 433                             path, root_dirid,
 434                             vol_args->name, namelen, 0);
 435         btrfs_free_path(path);
 436
 437         if (di && !IS_ERR(di)) {
 438                 ret = -EEXIST;
 439                 goto out;
 440         }
 441
 442         if (IS_ERR(di)) {
 443                 ret = PTR_ERR(di);
 444                 goto out;
 445         }
 446
 447         mutex_lock(&root->fs_info->drop_mutex);
 448         if (root == root->fs_info->tree_root)
 449                 ret = create_subvol(root, vol_args->name, namelen);
 450         else
 451                 ret = create_snapshot(root, vol_args->name, namelen);
 452         mutex_unlock(&root->fs_info->drop_mutex);
 453 out:
 454         kfree(vol_args);
 455         return ret;
 456 }
 457
 458 static int btrfs_ioctl_defrag(struct file *file)
 459 {
 460         struct inode *inode = fdentry(file)->d_inode;
 461         struct btrfs_root *root = BTRFS_I(inode)->root;
 462
 463         switch (inode->i_mode & S_IFMT) {
 464         case S_IFDIR:
 465                 btrfs_defrag_root(root, 0);
 466                 btrfs_defrag_root(root->fs_info->extent_root, 0);
 467                 break;
 468         case S_IFREG:
 469                 btrfs_defrag_file(file);
 470                 break;
 471         }
 472
 473         return 0;
 474 }
 475
 476 long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 477 {
 478         struct btrfs_ioctl_vol_args *vol_args;
 479         int ret;
 480
 481         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 482
 483         if (!vol_args)
 484                 return -ENOMEM;
 485
 486         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 487                 ret = -EFAULT;
 488                 goto out;
 489         }
 490         ret = btrfs_init_new_device(root, vol_args->name);
 491
 492 out:
 493         kfree(vol_args);
 494         return ret;
 495 }
 496
 497 long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 498 {
 499         struct btrfs_ioctl_vol_args *vol_args;
 500         int ret;
 501
 502         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 503
 504         if (!vol_args)
 505                 return -ENOMEM;
 506
 507         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 508                 ret = -EFAULT;
 509                 goto out;
 510         }
 511         ret = btrfs_rm_device(root, vol_args->name);
 512
 513 out:
 514         kfree(vol_args);
 515         return ret;
 516 }
 517
 518 int dup_item_to_inode(struct btrfs_trans_handle *trans,
 519                        struct btrfs_root *root,
 520                        struct btrfs_path *path,
 521                        struct extent_buffer *leaf,
 522                        int slot,
 523                        struct btrfs_key *key,
 524                        u64 destino)
 525 {
 526         char *dup;
 527         int len = btrfs_item_size_nr(leaf, slot);
 528         struct btrfs_key ckey = *key;
 529         int ret = 0;
 530
 531         dup = kmalloc(len, GFP_NOFS);
 532         if (!dup)
 533                 return -ENOMEM;
 534
 535         read_extent_buffer(leaf, dup, btrfs_item_ptr_offset(leaf, slot), len);
 536         btrfs_release_path(root, path);
 537
 538         ckey.objectid = destino;
 539         ret = btrfs_insert_item(trans, root, &ckey, dup, len);
 540         kfree(dup);
 541         return ret;
 542 }
 543
 544 long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
 545 {
 546         struct inode *inode = fdentry(file)->d_inode;
 547         struct btrfs_root *root = BTRFS_I(inode)->root;
 548         struct file *src_file;
 549         struct inode *src;
 550         struct btrfs_trans_handle *trans;
 551         int ret;
 552         u64 pos;
 553         struct btrfs_path *path;
 554         struct btrfs_key key;
 555         struct extent_buffer *leaf;
 556         u32 nritems;
 557         int slot;
 558
 559         src_file = fget(src_fd);
 560         if (!src_file)
 561                 return -EBADF;
 562         src = src_file->f_dentry->d_inode;
 563
 564         ret = -EXDEV;
 565         if (src->i_sb != inode->i_sb)
 566                 goto out_fput;
 567
 568         if (inode < src) {
 569                 mutex_lock(&inode->i_mutex);
 570                 mutex_lock(&src->i_mutex);
 571         } else {
 572                 mutex_lock(&src->i_mutex);
 573                 mutex_lock(&inode->i_mutex);
 574         }
 575
 576         ret = -ENOTEMPTY;
 577         if (inode->i_size)
 578                 goto out_unlock;
 579
 580         /* do any pending delalloc/csum calc on src, one way or
 581            another, and lock file content */
 582         while (1) {
 583                 filemap_write_and_wait(src->i_mapping);
 584                 lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 585                 if (BTRFS_I(src)->delalloc_bytes == 0)
 586                         break;
 587                 unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 588         }
 589
 590         trans = btrfs_start_transaction(root, 0);
 591         path = btrfs_alloc_path();
 592         if (!path) {
 593                 ret = -ENOMEM;
 594                 goto out;
 595         }
 596         key.offset = 0;
 597         key.type = BTRFS_EXTENT_DATA_KEY;
 598         key.objectid = src->i_ino;
 599         pos = 0;
 600         path->reada = 2;
 601
 602         while (1) {
 603                 /*
 604                  * note the key will change type as we walk through the
 605                  * tree.
 606                  */
 607                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 608                 if (ret < 0)
 609                         goto out;
 610
 611                 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
 612                         ret = btrfs_next_leaf(root, path);
 613                         if (ret < 0)
 614                                 goto out;
 615                         if (ret > 0)
 616                                 break;
 617                 }
 618                 leaf = path->nodes[0];
 619                 slot = path->slots[0];
 620                 btrfs_item_key_to_cpu(leaf, &key, slot);
 621                 nritems = btrfs_header_nritems(leaf);
 622
 623                 if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
 624                     key.objectid != src->i_ino)
 625                         break;
 626
 627                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 628                         struct btrfs_file_extent_item *extent;
 629                         int found_type;
 630                         pos = key.offset;
 631                         extent = btrfs_item_ptr(leaf, slot,
 632                                                 struct btrfs_file_extent_item);
 633                         found_type = btrfs_file_extent_type(leaf, extent);
 634                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 635                                 u64 len = btrfs_file_extent_num_bytes(leaf,
 636                                                                       extent);
 637                                 u64 ds = btrfs_file_extent_disk_bytenr(leaf,
 638                                                                        extent);
 639                                 u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
 640                                                                  extent);
 641                                 u64 off = btrfs_file_extent_offset(leaf,
 642                                                                    extent);
 643                                 btrfs_insert_file_extent(trans, root,
 644                                                          inode->i_ino, pos,
 645                                                          ds, dl, len, off);
 646                                 /* ds == 0 means there's a hole */
 647                                 if (ds != 0) {
 648                                         btrfs_inc_extent_ref(trans, root,
 649                                                      ds, dl,
 650                                                      root->root_key.objectid,
 651                                                      trans->transid,
 652                                                      inode->i_ino, pos);
 653                                 }
 654                                 pos = key.offset + len;
 655                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 656                                 ret = dup_item_to_inode(trans, root, path,
 657                                                         leaf, slot, &key,
 658                                                         inode->i_ino);
 659                                 if (ret)
 660                                         goto out;
 661                                 pos = key.offset + btrfs_item_size_nr(leaf,
 662                                                                       slot);
 663                         }
 664                 } else if (btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
 665                         ret = dup_item_to_inode(trans, root, path, leaf,
 666                                                 slot, &key, inode->i_ino);
 667
 668                         if (ret)
 669                                 goto out;
 670                 }
 671                 key.offset++;
 672                 btrfs_release_path(root, path);
 673         }
 674
 675         ret = 0;
 676 out:
 677         btrfs_free_path(path);
 678
 679         inode->i_blocks = src->i_blocks;
 680         i_size_write(inode, src->i_size);
 681         btrfs_update_inode(trans, root, inode);
 682
 683         unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 684
 685         btrfs_end_transaction(trans, root);
 686
 687 out_unlock:
 688         mutex_unlock(&src->i_mutex);
 689         mutex_unlock(&inode->i_mutex);
 690 out_fput:
 691         fput(src_file);
 692         return ret;
 693 }
 694
 695 /*
 696  * there are many ways the trans_start and trans_end ioctls can lead
 697  * to deadlocks.  They should only be used by applications that
 698  * basically own the machine, and have a very in depth understanding
 699  * of all the possible deadlocks and enospc problems.
 700  */
 701 long btrfs_ioctl_trans_start(struct file *file)
 702 {
 703         struct inode *inode = fdentry(file)->d_inode;
 704         struct btrfs_root *root = BTRFS_I(inode)->root;
 705         struct btrfs_trans_handle *trans;
 706         int ret = 0;
 707
 708         if (!capable(CAP_SYS_ADMIN))
 709                 return -EPERM;
 710
 711         if (file->private_data) {
 712                 ret = -EINPROGRESS;
 713                 goto out;
 714         }
 715         trans = btrfs_start_transaction(root, 0);
 716         if (trans)
 717                 file->private_data = trans;
 718         else
 719                 ret = -ENOMEM;
 720         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
 721 out:
 722         return ret;
 723 }
 724
 725 /*
 726  * there are many ways the trans_start and trans_end ioctls can lead
 727  * to deadlocks.  They should only be used by applications that
 728  * basically own the machine, and have a very in depth understanding
 729  * of all the possible deadlocks and enospc problems.
 730  */
 731 long btrfs_ioctl_trans_end(struct file *file)
 732 {
 733         struct inode *inode = fdentry(file)->d_inode;
 734         struct btrfs_root *root = BTRFS_I(inode)->root;
 735         struct btrfs_trans_handle *trans;
 736         int ret = 0;
 737
 738         trans = file->private_data;
 739         if (!trans) {
 740                 ret = -EINVAL;
 741                 goto out;
 742         }
 743         btrfs_end_transaction(trans, root);
 744         file->private_data = 0;
 745 out:
 746         return ret;
 747 }
 748
 749 long btrfs_ioctl(struct file *file, unsigned int
 750                 cmd, unsigned long arg)
 751 {
 752         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 753
 754         switch (cmd) {
 755         case BTRFS_IOC_SNAP_CREATE:
 756                 return btrfs_ioctl_snap_create(root, (void __user *)arg);
 757         case BTRFS_IOC_DEFRAG:
 758                 return btrfs_ioctl_defrag(file);
 759         case BTRFS_IOC_RESIZE:
 760                 return btrfs_ioctl_resize(root, (void __user *)arg);
 761         case BTRFS_IOC_ADD_DEV:
 762                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
 763         case BTRFS_IOC_RM_DEV:
 764                 return btrfs_ioctl_rm_dev(root, (void __user *)arg);
 765         case BTRFS_IOC_BALANCE:
 766                 return btrfs_balance(root->fs_info->dev_root);
 767         case BTRFS_IOC_CLONE:
 768                 return btrfs_ioctl_clone(file, arg);
 769         case BTRFS_IOC_TRANS_START:
 770                 return btrfs_ioctl_trans_start(file);
 771         case BTRFS_IOC_TRANS_END:
 772                 return btrfs_ioctl_trans_end(file);
 773         case BTRFS_IOC_SYNC:
 774                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
 775                 return 0;
 776         }
 777
 778         return -ENOTTY;
 779 }