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/fsnotify.h>
  25 #include <linux/pagemap.h>
  26 #include <linux/highmem.h>
  27 #include <linux/time.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/backing-dev.h>
  32 #include <linux/mount.h>
  33 #include <linux/mpage.h>
  34 #include <linux/namei.h>
  35 #include <linux/swap.h>
  36 #include <linux/writeback.h>
  37 #include <linux/statfs.h>
  38 #include <linux/compat.h>
  39 #include <linux/bit_spinlock.h>
  40 #include <linux/security.h>
  41 #include <linux/version.h>
  42 #include <linux/xattr.h>
  43 #include <linux/vmalloc.h>
  44 #include "ctree.h"
  45 #include "disk-io.h"
  46 #include "transaction.h"
  47 #include "btrfs_inode.h"
  48 #include "ioctl.h"
  49 #include "print-tree.h"
  50 #include "volumes.h"
  51 #include "locking.h"
  52
  53
  54
  55 static noinline int create_subvol(struct btrfs_root *root,
  56                                   struct dentry *dentry,
  57                                   char *name, int namelen)
  58 {
  59         struct btrfs_trans_handle *trans;
  60         struct btrfs_key key;
  61         struct btrfs_root_item root_item;
  62         struct btrfs_inode_item *inode_item;
  63         struct extent_buffer *leaf;
  64         struct btrfs_root *new_root = root;
  65         struct inode *dir;
  66         int ret;
  67         int err;
  68         u64 objectid;
  69         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
  70         unsigned long nr = 1;
  71
  72         ret = btrfs_check_free_space(root, 1, 0);
  73         if (ret)
  74                 goto fail_commit;
  75
  76         trans = btrfs_start_transaction(root, 1);
  77         BUG_ON(!trans);
  78
  79         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
  80                                        0, &objectid);
  81         if (ret)
  82                 goto fail;
  83
  84         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
  85                                       objectid, trans->transid, 0, 0, 0);
  86         if (IS_ERR(leaf)) {
  87                 ret = PTR_ERR(leaf);
  88                 goto fail;
  89         }
  90
  91         btrfs_set_header_nritems(leaf, 0);
  92         btrfs_set_header_level(leaf, 0);
  93         btrfs_set_header_bytenr(leaf, leaf->start);
  94         btrfs_set_header_generation(leaf, trans->transid);
  95         btrfs_set_header_owner(leaf, objectid);
  96
  97         write_extent_buffer(leaf, root->fs_info->fsid,
  98                             (unsigned long)btrfs_header_fsid(leaf),
  99                             BTRFS_FSID_SIZE);
 100         btrfs_mark_buffer_dirty(leaf);
 101
 102         inode_item = &root_item.inode;
 103         memset(inode_item, 0, sizeof(*inode_item));
 104         inode_item->generation = cpu_to_le64(1);
 105         inode_item->size = cpu_to_le64(3);
 106         inode_item->nlink = cpu_to_le32(1);
 107         inode_item->nbytes = cpu_to_le64(root->leafsize);
 108         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 109
 110         btrfs_set_root_bytenr(&root_item, leaf->start);
 111         btrfs_set_root_generation(&root_item, trans->transid);
 112         btrfs_set_root_level(&root_item, 0);
 113         btrfs_set_root_refs(&root_item, 1);
 114         btrfs_set_root_used(&root_item, 0);
 115
 116         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 117         root_item.drop_level = 0;
 118
 119         btrfs_tree_unlock(leaf);
 120         free_extent_buffer(leaf);
 121         leaf = NULL;
 122
 123         btrfs_set_root_dirid(&root_item, new_dirid);
 124
 125         key.objectid = objectid;
 126         key.offset = 1;
 127         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 128         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 129                                 &root_item);
 130         if (ret)
 131                 goto fail;
 132
 133         /*
 134          * insert the directory item
 135          */
 136         key.offset = (u64)-1;
 137         dir = root->fs_info->sb->s_root->d_inode;
 138         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 139                                     name, namelen, dir->i_ino, &key,
 140                                     BTRFS_FT_DIR, 0);
 141         if (ret)
 142                 goto fail;
 143
 144         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
 145                              name, namelen, objectid,
 146                              root->fs_info->sb->s_root->d_inode->i_ino, 0);
 147         if (ret)
 148                 goto fail;
 149
 150         ret = btrfs_commit_transaction(trans, root);
 151         if (ret)
 152                 goto fail_commit;
 153
 154         new_root = btrfs_read_fs_root(root->fs_info, &key, name, namelen);
 155         BUG_ON(!new_root);
 156
 157         trans = btrfs_start_transaction(new_root, 1);
 158         BUG_ON(!trans);
 159
 160         ret = btrfs_create_subvol_root(new_root, dentry, trans, new_dirid,
 161                                        BTRFS_I(dir)->block_group);
 162         if (ret)
 163                 goto fail;
 164
 165 fail:
 166         nr = trans->blocks_used;
 167         err = btrfs_commit_transaction(trans, new_root);
 168         if (err && !ret)
 169                 ret = err;
 170 fail_commit:
 171         btrfs_btree_balance_dirty(root, nr);
 172         return ret;
 173 }
 174
 175 static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 176 {
 177         struct btrfs_pending_snapshot *pending_snapshot;
 178         struct btrfs_trans_handle *trans;
 179         int ret;
 180         int err;
 181         unsigned long nr = 0;
 182
 183         if (!root->ref_cows)
 184                 return -EINVAL;
 185
 186         ret = btrfs_check_free_space(root, 1, 0);
 187         if (ret)
 188                 goto fail_unlock;
 189
 190         pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
 191         if (!pending_snapshot) {
 192                 ret = -ENOMEM;
 193                 goto fail_unlock;
 194         }
 195         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
 196         if (!pending_snapshot->name) {
 197                 ret = -ENOMEM;
 198                 kfree(pending_snapshot);
 199                 goto fail_unlock;
 200         }
 201         memcpy(pending_snapshot->name, name, namelen);
 202         pending_snapshot->name[namelen] = '\0';
 203         trans = btrfs_start_transaction(root, 1);
 204         BUG_ON(!trans);
 205         pending_snapshot->root = root;
 206         list_add(&pending_snapshot->list,
 207                  &trans->transaction->pending_snapshots);
 208         ret = btrfs_update_inode(trans, root, root->inode);
 209         err = btrfs_commit_transaction(trans, root);
 210
 211 fail_unlock:
 212         btrfs_btree_balance_dirty(root, nr);
 213         return ret;
 214 }
 215
 216 /* copy of may_create in fs/namei.c() */
 217 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 218 {
 219         if (child->d_inode)
 220                 return -EEXIST;
 221         if (IS_DEADDIR(dir))
 222                 return -ENOENT;
 223         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
 224 }
 225
 226 /*
 227  * Create a new subvolume below @parent.  This is largely modeled after
 228  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 229  * inside this filesystem so it's quite a bit simpler.
 230  */
 231 static noinline int btrfs_mksubvol(struct path *parent, char *name,
 232                                    int mode, int namelen)
 233 {
 234         struct dentry *dentry;
 235         int error;
 236
 237         mutex_lock_nested(&parent->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 238
 239         dentry = lookup_one_len(name, parent->dentry, namelen);
 240         error = PTR_ERR(dentry);
 241         if (IS_ERR(dentry))
 242                 goto out_unlock;
 243
 244         error = -EEXIST;
 245         if (dentry->d_inode)
 246                 goto out_dput;
 247
 248         if (!IS_POSIXACL(parent->dentry->d_inode))
 249                 mode &= ~current->fs->umask;
 250         error = mnt_want_write(parent->mnt);
 251         if (error)
 252                 goto out_dput;
 253
 254         error = btrfs_may_create(parent->dentry->d_inode, dentry);
 255         if (error)
 256                 goto out_drop_write;
 257
 258         /*
 259          * Actually perform the low-level subvolume creation after all
 260          * this VFS fuzz.
 261          *
 262          * Eventually we want to pass in an inode under which we create this
 263          * subvolume, but for now all are under the filesystem root.
 264          *
 265          * Also we should pass on the mode eventually to allow creating new
 266          * subvolume with specific mode bits.
 267          */
 268         error = create_subvol(BTRFS_I(parent->dentry->d_inode)->root, dentry,
 269                               name, namelen);
 270         if (error)
 271                 goto out_drop_write;
 272
 273         fsnotify_mkdir(parent->dentry->d_inode, dentry);
 274 out_drop_write:
 275         mnt_drop_write(parent->mnt);
 276 out_dput:
 277         dput(dentry);
 278 out_unlock:
 279         mutex_unlock(&parent->dentry->d_inode->i_mutex);
 280         return error;
 281 }
 282
 283
 284 int btrfs_defrag_file(struct file *file)
 285 {
 286         struct inode *inode = fdentry(file)->d_inode;
 287         struct btrfs_root *root = BTRFS_I(inode)->root;
 288         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 289         struct btrfs_ordered_extent *ordered;
 290         struct page *page;
 291         unsigned long last_index;
 292         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 293         unsigned long total_read = 0;
 294         u64 page_start;
 295         u64 page_end;
 296         unsigned long i;
 297         int ret;
 298
 299         ret = btrfs_check_free_space(root, inode->i_size, 0);
 300         if (ret)
 301                 return -ENOSPC;
 302
 303         mutex_lock(&inode->i_mutex);
 304         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 305         for (i = 0; i <= last_index; i++) {
 306                 if (total_read % ra_pages == 0) {
 307                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 308                                        min(last_index, i + ra_pages - 1));
 309                 }
 310                 total_read++;
 311 again:
 312                 page = grab_cache_page(inode->i_mapping, i);
 313                 if (!page)
 314                         goto out_unlock;
 315                 if (!PageUptodate(page)) {
 316                         btrfs_readpage(NULL, page);
 317                         lock_page(page);
 318                         if (!PageUptodate(page)) {
 319                                 unlock_page(page);
 320                                 page_cache_release(page);
 321                                 goto out_unlock;
 322                         }
 323                 }
 324
 325                 wait_on_page_writeback(page);
 326
 327                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 328                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 329                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 330
 331                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
 332                 if (ordered) {
 333                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 334                         unlock_page(page);
 335                         page_cache_release(page);
 336                         btrfs_start_ordered_extent(inode, ordered, 1);
 337                         btrfs_put_ordered_extent(ordered);
 338                         goto again;
 339                 }
 340                 set_page_extent_mapped(page);
 341
 342                 /*
 343                  * this makes sure page_mkwrite is called on the
 344                  * page if it is dirtied again later
 345                  */
 346                 clear_page_dirty_for_io(page);
 347
 348                 btrfs_set_extent_delalloc(inode, page_start, page_end);
 349
 350                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 351                 set_page_dirty(page);
 352                 unlock_page(page);
 353                 page_cache_release(page);
 354                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 355         }
 356
 357 out_unlock:
 358         mutex_unlock(&inode->i_mutex);
 359         return 0;
 360 }
 361
 362 /*
 363  * Called inside transaction, so use GFP_NOFS
 364  */
 365
 366 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 367 {
 368         u64 new_size;
 369         u64 old_size;
 370         u64 devid = 1;
 371         struct btrfs_ioctl_vol_args *vol_args;
 372         struct btrfs_trans_handle *trans;
 373         struct btrfs_device *device = NULL;
 374         char *sizestr;
 375         char *devstr = NULL;
 376         int ret = 0;
 377         int namelen;
 378         int mod = 0;
 379
 380         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 381
 382         if (!vol_args)
 383                 return -ENOMEM;
 384
 385         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 386                 ret = -EFAULT;
 387                 goto out;
 388         }
 389
 390         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 391         namelen = strlen(vol_args->name);
 392
 393         mutex_lock(&root->fs_info->volume_mutex);
 394         sizestr = vol_args->name;
 395         devstr = strchr(sizestr, ':');
 396         if (devstr) {
 397                 char *end;
 398                 sizestr = devstr + 1;
 399                 *devstr = '\0';
 400                 devstr = vol_args->name;
 401                 devid = simple_strtoull(devstr, &end, 10);
 402                 printk(KERN_INFO "resizing devid %llu\n", devid);
 403         }
 404         device = btrfs_find_device(root, devid, NULL);
 405         if (!device) {
 406                 printk(KERN_INFO "resizer unable to find device %llu\n", devid);
 407                 ret = -EINVAL;
 408                 goto out_unlock;
 409         }
 410         if (!strcmp(sizestr, "max"))
 411                 new_size = device->bdev->bd_inode->i_size;
 412         else {
 413                 if (sizestr[0] == '-') {
 414                         mod = -1;
 415                         sizestr++;
 416                 } else if (sizestr[0] == '+') {
 417                         mod = 1;
 418                         sizestr++;
 419                 }
 420                 new_size = btrfs_parse_size(sizestr);
 421                 if (new_size == 0) {
 422                         ret = -EINVAL;
 423                         goto out_unlock;
 424                 }
 425         }
 426
 427         old_size = device->total_bytes;
 428
 429         if (mod < 0) {
 430                 if (new_size > old_size) {
 431                         ret = -EINVAL;
 432                         goto out_unlock;
 433                 }
 434                 new_size = old_size - new_size;
 435         } else if (mod > 0) {
 436                 new_size = old_size + new_size;
 437         }
 438
 439         if (new_size < 256 * 1024 * 1024) {
 440                 ret = -EINVAL;
 441                 goto out_unlock;
 442         }
 443         if (new_size > device->bdev->bd_inode->i_size) {
 444                 ret = -EFBIG;
 445                 goto out_unlock;
 446         }
 447
 448         do_div(new_size, root->sectorsize);
 449         new_size *= root->sectorsize;
 450
 451         printk(KERN_INFO "new size for %s is %llu\n",
 452                 device->name, (unsigned long long)new_size);
 453
 454         if (new_size > old_size) {
 455                 trans = btrfs_start_transaction(root, 1);
 456                 ret = btrfs_grow_device(trans, device, new_size);
 457                 btrfs_commit_transaction(trans, root);
 458         } else {
 459                 ret = btrfs_shrink_device(device, new_size);
 460         }
 461
 462 out_unlock:
 463         mutex_unlock(&root->fs_info->volume_mutex);
 464 out:
 465         kfree(vol_args);
 466         return ret;
 467 }
 468
 469 static noinline int btrfs_ioctl_snap_create(struct file *file,
 470                                             void __user *arg)
 471 {
 472         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 473         struct btrfs_ioctl_vol_args *vol_args;
 474         struct btrfs_dir_item *di;
 475         struct btrfs_path *path;
 476         u64 root_dirid;
 477         int namelen;
 478         int ret;
 479
 480         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 481
 482         if (!vol_args)
 483                 return -ENOMEM;
 484
 485         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 486                 ret = -EFAULT;
 487                 goto out;
 488         }
 489
 490         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 491         namelen = strlen(vol_args->name);
 492         if (strchr(vol_args->name, '/')) {
 493                 ret = -EINVAL;
 494                 goto out;
 495         }
 496
 497         path = btrfs_alloc_path();
 498         if (!path) {
 499                 ret = -ENOMEM;
 500                 goto out;
 501         }
 502
 503         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 504         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
 505                             path, root_dirid,
 506                             vol_args->name, namelen, 0);
 507         btrfs_free_path(path);
 508
 509         if (di && !IS_ERR(di)) {
 510                 ret = -EEXIST;
 511                 goto out;
 512         }
 513
 514         if (IS_ERR(di)) {
 515                 ret = PTR_ERR(di);
 516                 goto out;
 517         }
 518
 519         if (root == root->fs_info->tree_root) {
 520                 ret = btrfs_mksubvol(&file->f_path, vol_args->name,
 521                                      file->f_path.dentry->d_inode->i_mode,
 522                                      namelen);
 523         } else {
 524                 ret = create_snapshot(root, vol_args->name, namelen);
 525         }
 526
 527 out:
 528         kfree(vol_args);
 529         return ret;
 530 }
 531
 532 static int btrfs_ioctl_defrag(struct file *file)
 533 {
 534         struct inode *inode = fdentry(file)->d_inode;
 535         struct btrfs_root *root = BTRFS_I(inode)->root;
 536
 537         switch (inode->i_mode & S_IFMT) {
 538         case S_IFDIR:
 539                 btrfs_defrag_root(root, 0);
 540                 btrfs_defrag_root(root->fs_info->extent_root, 0);
 541                 break;
 542         case S_IFREG:
 543                 btrfs_defrag_file(file);
 544                 break;
 545         }
 546
 547         return 0;
 548 }
 549
 550 long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 551 {
 552         struct btrfs_ioctl_vol_args *vol_args;
 553         int ret;
 554
 555         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 556
 557         if (!vol_args)
 558                 return -ENOMEM;
 559
 560         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 561                 ret = -EFAULT;
 562                 goto out;
 563         }
 564         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 565         ret = btrfs_init_new_device(root, vol_args->name);
 566
 567 out:
 568         kfree(vol_args);
 569         return ret;
 570 }
 571
 572 long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 573 {
 574         struct btrfs_ioctl_vol_args *vol_args;
 575         int ret;
 576
 577         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 578
 579         if (!vol_args)
 580                 return -ENOMEM;
 581
 582         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 583                 ret = -EFAULT;
 584                 goto out;
 585         }
 586         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 587         ret = btrfs_rm_device(root, vol_args->name);
 588
 589 out:
 590         kfree(vol_args);
 591         return ret;
 592 }
 593
 594 long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
 595 {
 596         struct inode *inode = fdentry(file)->d_inode;
 597         struct btrfs_root *root = BTRFS_I(inode)->root;
 598         struct file *src_file;
 599         struct inode *src;
 600         struct btrfs_trans_handle *trans;
 601         struct btrfs_path *path;
 602         struct extent_buffer *leaf;
 603         char *buf;
 604         struct btrfs_key key;
 605         u32 nritems;
 606         int slot;
 607         int ret;
 608
 609         src_file = fget(src_fd);
 610         if (!src_file)
 611                 return -EBADF;
 612         src = src_file->f_dentry->d_inode;
 613
 614         ret = -EISDIR;
 615         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
 616                 goto out_fput;
 617
 618         ret = -EXDEV;
 619         if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
 620                 goto out_fput;
 621
 622         ret = -ENOMEM;
 623         buf = vmalloc(btrfs_level_size(root, 0));
 624         if (!buf)
 625                 goto out_fput;
 626
 627         path = btrfs_alloc_path();
 628         if (!path) {
 629                 vfree(buf);
 630                 goto out_fput;
 631         }
 632         path->reada = 2;
 633
 634         if (inode < src) {
 635                 mutex_lock(&inode->i_mutex);
 636                 mutex_lock(&src->i_mutex);
 637         } else {
 638                 mutex_lock(&src->i_mutex);
 639                 mutex_lock(&inode->i_mutex);
 640         }
 641
 642         ret = -ENOTEMPTY;
 643         if (inode->i_size)
 644                 goto out_unlock;
 645
 646         /* do any pending delalloc/csum calc on src, one way or
 647            another, and lock file content */
 648         while (1) {
 649                 struct btrfs_ordered_extent *ordered;
 650                 lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 651                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
 652                 if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
 653                         break;
 654                 unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 655                 if (ordered)
 656                         btrfs_put_ordered_extent(ordered);
 657                 btrfs_wait_ordered_range(src, 0, (u64)-1);
 658         }
 659
 660         trans = btrfs_start_transaction(root, 1);
 661         BUG_ON(!trans);
 662
 663         key.objectid = src->i_ino;
 664         key.type = BTRFS_EXTENT_DATA_KEY;
 665         key.offset = 0;
 666
 667         while (1) {
 668                 /*
 669                  * note the key will change type as we walk through the
 670                  * tree.
 671                  */
 672                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 673                 if (ret < 0)
 674                         goto out;
 675
 676                 nritems = btrfs_header_nritems(path->nodes[0]);
 677                 if (path->slots[0] >= nritems) {
 678                         ret = btrfs_next_leaf(root, path);
 679                         if (ret < 0)
 680                                 goto out;
 681                         if (ret > 0)
 682                                 break;
 683                         nritems = btrfs_header_nritems(path->nodes[0]);
 684                 }
 685                 leaf = path->nodes[0];
 686                 slot = path->slots[0];
 687
 688                 btrfs_item_key_to_cpu(leaf, &key, slot);
 689                 if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
 690                     key.objectid != src->i_ino)
 691                         break;
 692
 693                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY ||
 694                     btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
 695                         u32 size;
 696                         struct btrfs_key new_key;
 697
 698                         size = btrfs_item_size_nr(leaf, slot);
 699                         read_extent_buffer(leaf, buf,
 700                                            btrfs_item_ptr_offset(leaf, slot),
 701                                            size);
 702                         btrfs_release_path(root, path);
 703
 704                         memcpy(&new_key, &key, sizeof(new_key));
 705                         new_key.objectid = inode->i_ino;
 706                         ret = btrfs_insert_empty_item(trans, root, path,
 707                                                       &new_key, size);
 708                         if (ret)
 709                                 goto out;
 710
 711                         leaf = path->nodes[0];
 712                         slot = path->slots[0];
 713                         write_extent_buffer(leaf, buf,
 714                                             btrfs_item_ptr_offset(leaf, slot),
 715                                             size);
 716                         btrfs_mark_buffer_dirty(leaf);
 717                 }
 718
 719                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 720                         struct btrfs_file_extent_item *extent;
 721                         int found_type;
 722
 723                         extent = btrfs_item_ptr(leaf, slot,
 724                                                 struct btrfs_file_extent_item);
 725                         found_type = btrfs_file_extent_type(leaf, extent);
 726                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 727                                 u64 ds = btrfs_file_extent_disk_bytenr(leaf,
 728                                                                        extent);
 729                                 u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
 730                                                                  extent);
 731                                 /* ds == 0 means there's a hole */
 732                                 if (ds != 0) {
 733                                         ret = btrfs_inc_extent_ref(trans, root,
 734                                                      ds, dl, leaf->start,
 735                                                      root->root_key.objectid,
 736                                                      trans->transid,
 737                                                      inode->i_ino);
 738                                         BUG_ON(ret);
 739                                 }
 740                         }
 741                 }
 742                 btrfs_release_path(root, path);
 743                 key.offset++;
 744         }
 745         ret = 0;
 746 out:
 747         btrfs_release_path(root, path);
 748         if (ret == 0) {
 749                 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 750                 inode_set_bytes(inode, inode_get_bytes(src));
 751                 btrfs_i_size_write(inode, src->i_size);
 752                 BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
 753                 ret = btrfs_update_inode(trans, root, inode);
 754         }
 755         btrfs_end_transaction(trans, root);
 756         unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 757         if (ret)
 758                 vmtruncate(inode, 0);
 759 out_unlock:
 760         mutex_unlock(&src->i_mutex);
 761         mutex_unlock(&inode->i_mutex);
 762         vfree(buf);
 763         btrfs_free_path(path);
 764 out_fput:
 765         fput(src_file);
 766         return ret;
 767 }
 768
 769 /*
 770  * there are many ways the trans_start and trans_end ioctls can lead
 771  * to deadlocks.  They should only be used by applications that
 772  * basically own the machine, and have a very in depth understanding
 773  * of all the possible deadlocks and enospc problems.
 774  */
 775 long btrfs_ioctl_trans_start(struct file *file)
 776 {
 777         struct inode *inode = fdentry(file)->d_inode;
 778         struct btrfs_root *root = BTRFS_I(inode)->root;
 779         struct btrfs_trans_handle *trans;
 780         int ret = 0;
 781
 782         if (!capable(CAP_SYS_ADMIN))
 783                 return -EPERM;
 784
 785         if (file->private_data) {
 786                 ret = -EINPROGRESS;
 787                 goto out;
 788         }
 789
 790         mutex_lock(&root->fs_info->trans_mutex);
 791         root->fs_info->open_ioctl_trans++;
 792         mutex_unlock(&root->fs_info->trans_mutex);
 793
 794         trans = btrfs_start_ioctl_transaction(root, 0);
 795         if (trans)
 796                 file->private_data = trans;
 797         else
 798                 ret = -ENOMEM;
 799         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
 800 out:
 801         return ret;
 802 }
 803
 804 /*
 805  * there are many ways the trans_start and trans_end ioctls can lead
 806  * to deadlocks.  They should only be used by applications that
 807  * basically own the machine, and have a very in depth understanding
 808  * of all the possible deadlocks and enospc problems.
 809  */
 810 long btrfs_ioctl_trans_end(struct file *file)
 811 {
 812         struct inode *inode = fdentry(file)->d_inode;
 813         struct btrfs_root *root = BTRFS_I(inode)->root;
 814         struct btrfs_trans_handle *trans;
 815         int ret = 0;
 816
 817         trans = file->private_data;
 818         if (!trans) {
 819                 ret = -EINVAL;
 820                 goto out;
 821         }
 822         btrfs_end_transaction(trans, root);
 823         file->private_data = NULL;
 824
 825         mutex_lock(&root->fs_info->trans_mutex);
 826         root->fs_info->open_ioctl_trans--;
 827         mutex_unlock(&root->fs_info->trans_mutex);
 828
 829 out:
 830         return ret;
 831 }
 832
 833 long btrfs_ioctl(struct file *file, unsigned int
 834                 cmd, unsigned long arg)
 835 {
 836         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 837
 838         switch (cmd) {
 839         case BTRFS_IOC_SNAP_CREATE:
 840                 return btrfs_ioctl_snap_create(file, (void __user *)arg);
 841         case BTRFS_IOC_DEFRAG:
 842                 return btrfs_ioctl_defrag(file);
 843         case BTRFS_IOC_RESIZE:
 844                 return btrfs_ioctl_resize(root, (void __user *)arg);
 845         case BTRFS_IOC_ADD_DEV:
 846                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
 847         case BTRFS_IOC_RM_DEV:
 848                 return btrfs_ioctl_rm_dev(root, (void __user *)arg);
 849         case BTRFS_IOC_BALANCE:
 850                 return btrfs_balance(root->fs_info->dev_root);
 851         case BTRFS_IOC_CLONE:
 852                 return btrfs_ioctl_clone(file, arg);
 853         case BTRFS_IOC_TRANS_START:
 854                 return btrfs_ioctl_trans_start(file);
 855         case BTRFS_IOC_TRANS_END:
 856                 return btrfs_ioctl_trans_end(file);
 857         case BTRFS_IOC_SYNC:
 858                 btrfs_start_delalloc_inodes(root);
 859                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
 860                 return 0;
 861         }
 862
 863         return -ENOTTY;
 864 }