git.oblomov.eu Git - linux-2.6/blob - 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 page *page;
 217         unsigned long last_index;
 218         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 219         unsigned long total_read = 0;
 220         u64 page_start;
 221         u64 page_end;
 222         unsigned long i;
 223         int ret;
 224
 225         ret = btrfs_check_free_space(root, inode->i_size, 0);
 226         if (ret)
 227                 return -ENOSPC;
 228
 229         mutex_lock(&inode->i_mutex);
 230         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 231         for (i = 0; i <= last_index; i++) {
 232                 if (total_read % ra_pages == 0) {
 233                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 234                                        min(last_index, i + ra_pages - 1));
 235                 }
 236                 total_read++;
 237                 page = grab_cache_page(inode->i_mapping, i);
 238                 if (!page)
 239                         goto out_unlock;
 240                 if (!PageUptodate(page)) {
 241                         btrfs_readpage(NULL, page);
 242                         lock_page(page);
 243                         if (!PageUptodate(page)) {
 244                                 unlock_page(page);
 245                                 page_cache_release(page);
 246                                 goto out_unlock;
 247                         }
 248                 }
 249
 250 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 251                 ClearPageDirty(page);
 252 #else
 253                 cancel_dirty_page(page, PAGE_CACHE_SIZE);
 254 #endif
 255                 wait_on_page_writeback(page);
 256                 set_page_extent_mapped(page);
 257
 258                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 259                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 260
 261                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 262                 set_extent_delalloc(io_tree, page_start,
 263                                     page_end, GFP_NOFS);
 264
 265                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 266                 set_page_dirty(page);
 267                 unlock_page(page);
 268                 page_cache_release(page);
 269                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 270         }
 271
 272 out_unlock:
 273         mutex_unlock(&inode->i_mutex);
 274         return 0;
 275 }
 276
 277 /*
 278  * Called inside transaction, so use GFP_NOFS
 279  */
 280
 281 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 282 {
 283         u64 new_size;
 284         u64 old_size;
 285         u64 devid = 1;
 286         struct btrfs_ioctl_vol_args *vol_args;
 287         struct btrfs_trans_handle *trans;
 288         struct btrfs_device *device = NULL;
 289         char *sizestr;
 290         char *devstr = NULL;
 291         int ret = 0;
 292         int namelen;
 293         int mod = 0;
 294
 295         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 296
 297         if (!vol_args)
 298                 return -ENOMEM;
 299
 300         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 301                 ret = -EFAULT;
 302                 goto out;
 303         }
 304         namelen = strlen(vol_args->name);
 305         if (namelen > BTRFS_VOL_NAME_MAX) {
 306                 ret = -EINVAL;
 307                 goto out;
 308         }
 309
 310         mutex_lock(&root->fs_info->volume_mutex);
 311         sizestr = vol_args->name;
 312         devstr = strchr(sizestr, ':');
 313         if (devstr) {
 314                 char *end;
 315                 sizestr = devstr + 1;
 316                 *devstr = '\0';
 317                 devstr = vol_args->name;
 318                 devid = simple_strtoull(devstr, &end, 10);
 319                 printk(KERN_INFO "resizing devid %llu\n", devid);
 320         }
 321         device = btrfs_find_device(root, devid, NULL);
 322         if (!device) {
 323                 printk(KERN_INFO "resizer unable to find device %llu\n", devid);
 324                 ret = -EINVAL;
 325                 goto out_unlock;
 326         }
 327         if (!strcmp(sizestr, "max"))
 328                 new_size = device->bdev->bd_inode->i_size;
 329         else {
 330                 if (sizestr[0] == '-') {
 331                         mod = -1;
 332                         sizestr++;
 333                 } else if (sizestr[0] == '+') {
 334                         mod = 1;
 335                         sizestr++;
 336                 }
 337                 new_size = btrfs_parse_size(sizestr);
 338                 if (new_size == 0) {
 339                         ret = -EINVAL;
 340                         goto out_unlock;
 341                 }
 342         }
 343
 344         old_size = device->total_bytes;
 345
 346         if (mod < 0) {
 347                 if (new_size > old_size) {
 348                         ret = -EINVAL;
 349                         goto out_unlock;
 350                 }
 351                 new_size = old_size - new_size;
 352         } else if (mod > 0) {
 353                 new_size = old_size + new_size;
 354         }
 355
 356         if (new_size < 256 * 1024 * 1024) {
 357                 ret = -EINVAL;
 358                 goto out_unlock;
 359         }
 360         if (new_size > device->bdev->bd_inode->i_size) {
 361                 ret = -EFBIG;
 362                 goto out_unlock;
 363         }
 364
 365         do_div(new_size, root->sectorsize);
 366         new_size *= root->sectorsize;
 367
 368         printk(KERN_INFO "new size for %s is %llu\n",
 369                 device->name, (unsigned long long)new_size);
 370
 371         if (new_size > old_size) {
 372                 trans = btrfs_start_transaction(root, 1);
 373                 ret = btrfs_grow_device(trans, device, new_size);
 374                 btrfs_commit_transaction(trans, root);
 375         } else {
 376                 ret = btrfs_shrink_device(device, new_size);
 377         }
 378
 379 out_unlock:
 380         mutex_unlock(&root->fs_info->volume_mutex);
 381 out:
 382         kfree(vol_args);
 383         return ret;
 384 }
 385
 386 static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
 387                                             void __user *arg)
 388 {
 389         struct btrfs_ioctl_vol_args *vol_args;
 390         struct btrfs_dir_item *di;
 391         struct btrfs_path *path;
 392         u64 root_dirid;
 393         int namelen;
 394         int ret;
 395
 396         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 397
 398         if (!vol_args)
 399                 return -ENOMEM;
 400
 401         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 402                 ret = -EFAULT;
 403                 goto out;
 404         }
 405
 406         namelen = strlen(vol_args->name);
 407         if (namelen > BTRFS_VOL_NAME_MAX) {
 408                 ret = -EINVAL;
 409                 goto out;
 410         }
 411         if (strchr(vol_args->name, '/')) {
 412                 ret = -EINVAL;
 413                 goto out;
 414         }
 415
 416         path = btrfs_alloc_path();
 417         if (!path) {
 418                 ret = -ENOMEM;
 419                 goto out;
 420         }
 421
 422         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 423         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
 424                             path, root_dirid,
 425                             vol_args->name, namelen, 0);
 426         btrfs_free_path(path);
 427
 428         if (di && !IS_ERR(di)) {
 429                 ret = -EEXIST;
 430                 goto out;
 431         }
 432
 433         if (IS_ERR(di)) {
 434                 ret = PTR_ERR(di);
 435                 goto out;
 436         }
 437
 438         mutex_lock(&root->fs_info->drop_mutex);
 439         if (root == root->fs_info->tree_root)
 440                 ret = create_subvol(root, vol_args->name, namelen);
 441         else
 442                 ret = create_snapshot(root, vol_args->name, namelen);
 443         mutex_unlock(&root->fs_info->drop_mutex);
 444 out:
 445         kfree(vol_args);
 446         return ret;
 447 }
 448
 449 static int btrfs_ioctl_defrag(struct file *file)
 450 {
 451         struct inode *inode = fdentry(file)->d_inode;
 452         struct btrfs_root *root = BTRFS_I(inode)->root;
 453
 454         switch (inode->i_mode & S_IFMT) {
 455         case S_IFDIR:
 456                 btrfs_defrag_root(root, 0);
 457                 btrfs_defrag_root(root->fs_info->extent_root, 0);
 458                 break;
 459         case S_IFREG:
 460                 btrfs_defrag_file(file);
 461                 break;
 462         }
 463
 464         return 0;
 465 }
 466
 467 long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 468 {
 469         struct btrfs_ioctl_vol_args *vol_args;
 470         int ret;
 471
 472         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 473
 474         if (!vol_args)
 475                 return -ENOMEM;
 476
 477         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 478                 ret = -EFAULT;
 479                 goto out;
 480         }
 481         ret = btrfs_init_new_device(root, vol_args->name);
 482
 483 out:
 484         kfree(vol_args);
 485         return ret;
 486 }
 487
 488 long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 489 {
 490         struct btrfs_ioctl_vol_args *vol_args;
 491         int ret;
 492
 493         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 494
 495         if (!vol_args)
 496                 return -ENOMEM;
 497
 498         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 499                 ret = -EFAULT;
 500                 goto out;
 501         }
 502         ret = btrfs_rm_device(root, vol_args->name);
 503
 504 out:
 505         kfree(vol_args);
 506         return ret;
 507 }
 508
 509 int dup_item_to_inode(struct btrfs_trans_handle *trans,
 510                        struct btrfs_root *root,
 511                        struct btrfs_path *path,
 512                        struct extent_buffer *leaf,
 513                        int slot,
 514                        struct btrfs_key *key,
 515                        u64 destino)
 516 {
 517         char *dup;
 518         int len = btrfs_item_size_nr(leaf, slot);
 519         struct btrfs_key ckey = *key;
 520         int ret = 0;
 521
 522         dup = kmalloc(len, GFP_NOFS);
 523         if (!dup)
 524                 return -ENOMEM;
 525
 526         read_extent_buffer(leaf, dup, btrfs_item_ptr_offset(leaf, slot), len);
 527         btrfs_release_path(root, path);
 528
 529         ckey.objectid = destino;
 530         ret = btrfs_insert_item(trans, root, &ckey, dup, len);
 531         kfree(dup);
 532         return ret;
 533 }
 534
 535 long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
 536 {
 537         struct inode *inode = fdentry(file)->d_inode;
 538         struct btrfs_root *root = BTRFS_I(inode)->root;
 539         struct file *src_file;
 540         struct inode *src;
 541         struct btrfs_trans_handle *trans;
 542         int ret;
 543         u64 pos;
 544         struct btrfs_path *path;
 545         struct btrfs_key key;
 546         struct extent_buffer *leaf;
 547         u32 nritems;
 548         int slot;
 549
 550         src_file = fget(src_fd);
 551         if (!src_file)
 552                 return -EBADF;
 553         src = src_file->f_dentry->d_inode;
 554
 555         ret = -EXDEV;
 556         if (src->i_sb != inode->i_sb)
 557                 goto out_fput;
 558
 559         if (inode < src) {
 560                 mutex_lock(&inode->i_mutex);
 561                 mutex_lock(&src->i_mutex);
 562         } else {
 563                 mutex_lock(&src->i_mutex);
 564                 mutex_lock(&inode->i_mutex);
 565         }
 566
 567         ret = -ENOTEMPTY;
 568         if (inode->i_size)
 569                 goto out_unlock;
 570
 571         /* do any pending delalloc/csum calc on src, one way or
 572            another, and lock file content */
 573         while (1) {
 574                 filemap_write_and_wait(src->i_mapping);
 575                 lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 576                 if (BTRFS_I(src)->delalloc_bytes == 0)
 577                         break;
 578                 unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 579         }
 580
 581         trans = btrfs_start_transaction(root, 0);
 582         path = btrfs_alloc_path();
 583         if (!path) {
 584                 ret = -ENOMEM;
 585                 goto out;
 586         }
 587         key.offset = 0;
 588         key.type = BTRFS_EXTENT_DATA_KEY;
 589         key.objectid = src->i_ino;
 590         pos = 0;
 591         path->reada = 2;
 592
 593         while (1) {
 594                 /*
 595                  * note the key will change type as we walk through the
 596                  * tree.
 597                  */
 598                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 599                 if (ret < 0)
 600                         goto out;
 601
 602                 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
 603                         ret = btrfs_next_leaf(root, path);
 604                         if (ret < 0)
 605                                 goto out;
 606                         if (ret > 0)
 607                                 break;
 608                 }
 609                 leaf = path->nodes[0];
 610                 slot = path->slots[0];
 611                 btrfs_item_key_to_cpu(leaf, &key, slot);
 612                 nritems = btrfs_header_nritems(leaf);
 613
 614                 if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
 615                     key.objectid != src->i_ino)
 616                         break;
 617
 618                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 619                         struct btrfs_file_extent_item *extent;
 620                         int found_type;
 621                         pos = key.offset;
 622                         extent = btrfs_item_ptr(leaf, slot,
 623                                                 struct btrfs_file_extent_item);
 624                         found_type = btrfs_file_extent_type(leaf, extent);
 625                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 626                                 u64 len = btrfs_file_extent_num_bytes(leaf,
 627                                                                       extent);
 628                                 u64 ds = btrfs_file_extent_disk_bytenr(leaf,
 629                                                                        extent);
 630                                 u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
 631                                                                  extent);
 632                                 u64 off = btrfs_file_extent_offset(leaf,
 633                                                                    extent);
 634                                 btrfs_insert_file_extent(trans, root,
 635                                                          inode->i_ino, pos,
 636                                                          ds, dl, len, off);
 637                                 /* ds == 0 means there's a hole */
 638                                 if (ds != 0) {
 639                                         btrfs_inc_extent_ref(trans, root,
 640                                                      ds, dl,
 641                                                      root->root_key.objectid,
 642                                                      trans->transid,
 643                                                      inode->i_ino, pos);
 644                                 }
 645                                 pos = key.offset + len;
 646                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 647                                 ret = dup_item_to_inode(trans, root, path,
 648                                                         leaf, slot, &key,
 649                                                         inode->i_ino);
 650                                 if (ret)
 651                                         goto out;
 652                                 pos = key.offset + btrfs_item_size_nr(leaf,
 653                                                                       slot);
 654                         }
 655                 } else if (btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
 656                         ret = dup_item_to_inode(trans, root, path, leaf,
 657                                                 slot, &key, inode->i_ino);
 658
 659                         if (ret)
 660                                 goto out;
 661                 }
 662                 key.offset++;
 663                 btrfs_release_path(root, path);
 664         }
 665
 666         ret = 0;
 667 out:
 668         btrfs_free_path(path);
 669
 670         inode->i_blocks = src->i_blocks;
 671         i_size_write(inode, src->i_size);
 672         btrfs_update_inode(trans, root, inode);
 673
 674         unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 675
 676         btrfs_end_transaction(trans, root);
 677
 678 out_unlock:
 679         mutex_unlock(&src->i_mutex);
 680         mutex_unlock(&inode->i_mutex);
 681 out_fput:
 682         fput(src_file);
 683         return ret;
 684 }
 685
 686 /*
 687  * there are many ways the trans_start and trans_end ioctls can lead
 688  * to deadlocks.  They should only be used by applications that
 689  * basically own the machine, and have a very in depth understanding
 690  * of all the possible deadlocks and enospc problems.
 691  */
 692 long btrfs_ioctl_trans_start(struct file *file)
 693 {
 694         struct inode *inode = fdentry(file)->d_inode;
 695         struct btrfs_root *root = BTRFS_I(inode)->root;
 696         struct btrfs_trans_handle *trans;
 697         int ret = 0;
 698
 699         if (!capable(CAP_SYS_ADMIN))
 700                 return -EPERM;
 701
 702         if (file->private_data) {
 703                 ret = -EINPROGRESS;
 704                 goto out;
 705         }
 706         trans = btrfs_start_transaction(root, 0);
 707         if (trans)
 708                 file->private_data = trans;
 709         else
 710                 ret = -ENOMEM;
 711         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
 712 out:
 713         return ret;
 714 }
 715
 716 /*
 717  * there are many ways the trans_start and trans_end ioctls can lead
 718  * to deadlocks.  They should only be used by applications that
 719  * basically own the machine, and have a very in depth understanding
 720  * of all the possible deadlocks and enospc problems.
 721  */
 722 long btrfs_ioctl_trans_end(struct file *file)
 723 {
 724         struct inode *inode = fdentry(file)->d_inode;
 725         struct btrfs_root *root = BTRFS_I(inode)->root;
 726         struct btrfs_trans_handle *trans;
 727         int ret = 0;
 728
 729         trans = file->private_data;
 730         if (!trans) {
 731                 ret = -EINVAL;
 732                 goto out;
 733         }
 734         btrfs_end_transaction(trans, root);
 735         file->private_data = 0;
 736 out:
 737         return ret;
 738 }
 739
 740 long btrfs_ioctl(struct file *file, unsigned int
 741                 cmd, unsigned long arg)
 742 {
 743         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 744
 745         switch (cmd) {
 746         case BTRFS_IOC_SNAP_CREATE:
 747                 return btrfs_ioctl_snap_create(root, (void __user *)arg);
 748         case BTRFS_IOC_DEFRAG:
 749                 return btrfs_ioctl_defrag(file);
 750         case BTRFS_IOC_RESIZE:
 751                 return btrfs_ioctl_resize(root, (void __user *)arg);
 752         case BTRFS_IOC_ADD_DEV:
 753                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
 754         case BTRFS_IOC_RM_DEV:
 755                 return btrfs_ioctl_rm_dev(root, (void __user *)arg);
 756         case BTRFS_IOC_BALANCE:
 757                 return btrfs_balance(root->fs_info->dev_root);
 758         case BTRFS_IOC_CLONE:
 759                 return btrfs_ioctl_clone(file, arg);
 760         case BTRFS_IOC_TRANS_START:
 761                 return btrfs_ioctl_trans_start(file);
 762         case BTRFS_IOC_TRANS_END:
 763                 return btrfs_ioctl_trans_end(file);
 764         case BTRFS_IOC_SYNC:
 765                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
 766                 return 0;
 767         }
 768
 769         return -ENOTTY;
 770 }