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/backing-dev.h>
  31 #include <linux/mount.h>
  32 #include <linux/mpage.h>
  33 #include <linux/namei.h>
  34 #include <linux/swap.h>
  35 #include <linux/writeback.h>
  36 #include <linux/statfs.h>
  37 #include <linux/compat.h>
  38 #include <linux/bit_spinlock.h>
  39 #include <linux/security.h>
  40 #include <linux/xattr.h>
  41 #include <linux/vmalloc.h>
  42 #include "compat.h"
  43 #include "ctree.h"
  44 #include "disk-io.h"
  45 #include "transaction.h"
  46 #include "btrfs_inode.h"
  47 #include "ioctl.h"
  48 #include "print-tree.h"
  49 #include "volumes.h"
  50 #include "locking.h"
  51 #include "ctree.h"
  52
  53 /* Mask out flags that are inappropriate for the given type of inode. */
  54 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
  55 {
  56         if (S_ISDIR(mode))
  57                 return flags;
  58         else if (S_ISREG(mode))
  59                 return flags & ~FS_DIRSYNC_FL;
  60         else
  61                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
  62 }
  63
  64 /*
  65  * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
  66  */
  67 static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
  68 {
  69         unsigned int iflags = 0;
  70
  71         if (flags & BTRFS_INODE_SYNC)
  72                 iflags |= FS_SYNC_FL;
  73         if (flags & BTRFS_INODE_IMMUTABLE)
  74                 iflags |= FS_IMMUTABLE_FL;
  75         if (flags & BTRFS_INODE_APPEND)
  76                 iflags |= FS_APPEND_FL;
  77         if (flags & BTRFS_INODE_NODUMP)
  78                 iflags |= FS_NODUMP_FL;
  79         if (flags & BTRFS_INODE_NOATIME)
  80                 iflags |= FS_NOATIME_FL;
  81         if (flags & BTRFS_INODE_DIRSYNC)
  82                 iflags |= FS_DIRSYNC_FL;
  83
  84         return iflags;
  85 }
  86
  87 /*
  88  * Update inode->i_flags based on the btrfs internal flags.
  89  */
  90 void btrfs_update_iflags(struct inode *inode)
  91 {
  92         struct btrfs_inode *ip = BTRFS_I(inode);
  93
  94         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
  95
  96         if (ip->flags & BTRFS_INODE_SYNC)
  97                 inode->i_flags |= S_SYNC;
  98         if (ip->flags & BTRFS_INODE_IMMUTABLE)
  99                 inode->i_flags |= S_IMMUTABLE;
 100         if (ip->flags & BTRFS_INODE_APPEND)
 101                 inode->i_flags |= S_APPEND;
 102         if (ip->flags & BTRFS_INODE_NOATIME)
 103                 inode->i_flags |= S_NOATIME;
 104         if (ip->flags & BTRFS_INODE_DIRSYNC)
 105                 inode->i_flags |= S_DIRSYNC;
 106 }
 107
 108 /*
 109  * Inherit flags from the parent inode.
 110  *
 111  * Unlike extN we don't have any flags we don't want to inherit currently.
 112  */
 113 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
 114 {
 115         unsigned int flags;
 116
 117         if (!dir)
 118                 return;
 119
 120         flags = BTRFS_I(dir)->flags;
 121
 122         if (S_ISREG(inode->i_mode))
 123                 flags &= ~BTRFS_INODE_DIRSYNC;
 124         else if (!S_ISDIR(inode->i_mode))
 125                 flags &= (BTRFS_INODE_NODUMP | BTRFS_INODE_NOATIME);
 126
 127         BTRFS_I(inode)->flags = flags;
 128         btrfs_update_iflags(inode);
 129 }
 130
 131 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
 132 {
 133         struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
 134         unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
 135
 136         if (copy_to_user(arg, &flags, sizeof(flags)))
 137                 return -EFAULT;
 138         return 0;
 139 }
 140
 141 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 142 {
 143         struct inode *inode = file->f_path.dentry->d_inode;
 144         struct btrfs_inode *ip = BTRFS_I(inode);
 145         struct btrfs_root *root = ip->root;
 146         struct btrfs_trans_handle *trans;
 147         unsigned int flags, oldflags;
 148         int ret;
 149
 150         if (copy_from_user(&flags, arg, sizeof(flags)))
 151                 return -EFAULT;
 152
 153         if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
 154                       FS_NOATIME_FL | FS_NODUMP_FL | \
 155                       FS_SYNC_FL | FS_DIRSYNC_FL))
 156                 return -EOPNOTSUPP;
 157
 158         if (!is_owner_or_cap(inode))
 159                 return -EACCES;
 160
 161         mutex_lock(&inode->i_mutex);
 162
 163         flags = btrfs_mask_flags(inode->i_mode, flags);
 164         oldflags = btrfs_flags_to_ioctl(ip->flags);
 165         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
 166                 if (!capable(CAP_LINUX_IMMUTABLE)) {
 167                         ret = -EPERM;
 168                         goto out_unlock;
 169                 }
 170         }
 171
 172         ret = mnt_want_write(file->f_path.mnt);
 173         if (ret)
 174                 goto out_unlock;
 175
 176         if (flags & FS_SYNC_FL)
 177                 ip->flags |= BTRFS_INODE_SYNC;
 178         else
 179                 ip->flags &= ~BTRFS_INODE_SYNC;
 180         if (flags & FS_IMMUTABLE_FL)
 181                 ip->flags |= BTRFS_INODE_IMMUTABLE;
 182         else
 183                 ip->flags &= ~BTRFS_INODE_IMMUTABLE;
 184         if (flags & FS_APPEND_FL)
 185                 ip->flags |= BTRFS_INODE_APPEND;
 186         else
 187                 ip->flags &= ~BTRFS_INODE_APPEND;
 188         if (flags & FS_NODUMP_FL)
 189                 ip->flags |= BTRFS_INODE_NODUMP;
 190         else
 191                 ip->flags &= ~BTRFS_INODE_NODUMP;
 192         if (flags & FS_NOATIME_FL)
 193                 ip->flags |= BTRFS_INODE_NOATIME;
 194         else
 195                 ip->flags &= ~BTRFS_INODE_NOATIME;
 196         if (flags & FS_DIRSYNC_FL)
 197                 ip->flags |= BTRFS_INODE_DIRSYNC;
 198         else
 199                 ip->flags &= ~BTRFS_INODE_DIRSYNC;
 200
 201
 202         trans = btrfs_join_transaction(root, 1);
 203         BUG_ON(!trans);
 204
 205         ret = btrfs_update_inode(trans, root, inode);
 206         BUG_ON(ret);
 207
 208         btrfs_update_iflags(inode);
 209         inode->i_ctime = CURRENT_TIME;
 210         btrfs_end_transaction(trans, root);
 211
 212         mnt_drop_write(file->f_path.mnt);
 213  out_unlock:
 214         mutex_unlock(&inode->i_mutex);
 215         return 0;
 216 }
 217
 218 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 219 {
 220         struct inode *inode = file->f_path.dentry->d_inode;
 221
 222         return put_user(inode->i_generation, arg);
 223 }
 224
 225 static noinline int create_subvol(struct btrfs_root *root,
 226                                   struct dentry *dentry,
 227                                   char *name, int namelen)
 228 {
 229         struct btrfs_trans_handle *trans;
 230         struct btrfs_key key;
 231         struct btrfs_root_item root_item;
 232         struct btrfs_inode_item *inode_item;
 233         struct extent_buffer *leaf;
 234         struct btrfs_root *new_root;
 235         struct inode *dir = dentry->d_parent->d_inode;
 236         int ret;
 237         int err;
 238         u64 objectid;
 239         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
 240         u64 index = 0;
 241
 242         /*
 243          * 1 - inode item
 244          * 2 - refs
 245          * 1 - root item
 246          * 2 - dir items
 247          */
 248         ret = btrfs_reserve_metadata_space(root, 6);
 249         if (ret)
 250                 return ret;
 251
 252         trans = btrfs_start_transaction(root, 1);
 253         BUG_ON(!trans);
 254
 255         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
 256                                        0, &objectid);
 257         if (ret)
 258                 goto fail;
 259
 260         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
 261                                       0, objectid, NULL, 0, 0, 0);
 262         if (IS_ERR(leaf)) {
 263                 ret = PTR_ERR(leaf);
 264                 goto fail;
 265         }
 266
 267         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
 268         btrfs_set_header_bytenr(leaf, leaf->start);
 269         btrfs_set_header_generation(leaf, trans->transid);
 270         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
 271         btrfs_set_header_owner(leaf, objectid);
 272
 273         write_extent_buffer(leaf, root->fs_info->fsid,
 274                             (unsigned long)btrfs_header_fsid(leaf),
 275                             BTRFS_FSID_SIZE);
 276         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 277                             (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
 278                             BTRFS_UUID_SIZE);
 279         btrfs_mark_buffer_dirty(leaf);
 280
 281         inode_item = &root_item.inode;
 282         memset(inode_item, 0, sizeof(*inode_item));
 283         inode_item->generation = cpu_to_le64(1);
 284         inode_item->size = cpu_to_le64(3);
 285         inode_item->nlink = cpu_to_le32(1);
 286         inode_item->nbytes = cpu_to_le64(root->leafsize);
 287         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 288
 289         btrfs_set_root_bytenr(&root_item, leaf->start);
 290         btrfs_set_root_generation(&root_item, trans->transid);
 291         btrfs_set_root_level(&root_item, 0);
 292         btrfs_set_root_refs(&root_item, 1);
 293         btrfs_set_root_used(&root_item, leaf->len);
 294         btrfs_set_root_last_snapshot(&root_item, 0);
 295
 296         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 297         root_item.drop_level = 0;
 298
 299         btrfs_tree_unlock(leaf);
 300         free_extent_buffer(leaf);
 301         leaf = NULL;
 302
 303         btrfs_set_root_dirid(&root_item, new_dirid);
 304
 305         key.objectid = objectid;
 306         key.offset = 0;
 307         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 308         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 309                                 &root_item);
 310         if (ret)
 311                 goto fail;
 312
 313         key.offset = (u64)-1;
 314         new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
 315         BUG_ON(IS_ERR(new_root));
 316
 317         btrfs_record_root_in_trans(trans, new_root);
 318
 319         ret = btrfs_create_subvol_root(trans, new_root, new_dirid,
 320                                        BTRFS_I(dir)->block_group);
 321         /*
 322          * insert the directory item
 323          */
 324         ret = btrfs_set_inode_index(dir, &index);
 325         BUG_ON(ret);
 326
 327         ret = btrfs_insert_dir_item(trans, root,
 328                                     name, namelen, dir->i_ino, &key,
 329                                     BTRFS_FT_DIR, index);
 330         if (ret)
 331                 goto fail;
 332
 333         btrfs_i_size_write(dir, dir->i_size + namelen * 2);
 334         ret = btrfs_update_inode(trans, root, dir);
 335         BUG_ON(ret);
 336
 337         ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
 338                                  objectid, root->root_key.objectid,
 339                                  dir->i_ino, index, name, namelen);
 340
 341         BUG_ON(ret);
 342
 343         d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
 344 fail:
 345         err = btrfs_commit_transaction(trans, root);
 346         if (err && !ret)
 347                 ret = err;
 348
 349         btrfs_unreserve_metadata_space(root, 6);
 350         return ret;
 351 }
 352
 353 static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
 354                            char *name, int namelen)
 355 {
 356         struct inode *inode;
 357         struct btrfs_pending_snapshot *pending_snapshot;
 358         struct btrfs_trans_handle *trans;
 359         int ret;
 360
 361         if (!root->ref_cows)
 362                 return -EINVAL;
 363
 364         /*
 365          * 1 - inode item
 366          * 2 - refs
 367          * 1 - root item
 368          * 2 - dir items
 369          */
 370         ret = btrfs_reserve_metadata_space(root, 6);
 371         if (ret)
 372                 goto fail;
 373
 374         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
 375         if (!pending_snapshot) {
 376                 ret = -ENOMEM;
 377                 btrfs_unreserve_metadata_space(root, 6);
 378                 goto fail;
 379         }
 380         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
 381         if (!pending_snapshot->name) {
 382                 ret = -ENOMEM;
 383                 kfree(pending_snapshot);
 384                 btrfs_unreserve_metadata_space(root, 6);
 385                 goto fail;
 386         }
 387         memcpy(pending_snapshot->name, name, namelen);
 388         pending_snapshot->name[namelen] = '\0';
 389         pending_snapshot->dentry = dentry;
 390         trans = btrfs_start_transaction(root, 1);
 391         BUG_ON(!trans);
 392         pending_snapshot->root = root;
 393         list_add(&pending_snapshot->list,
 394                  &trans->transaction->pending_snapshots);
 395         ret = btrfs_commit_transaction(trans, root);
 396         BUG_ON(ret);
 397         btrfs_unreserve_metadata_space(root, 6);
 398
 399         inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry);
 400         if (IS_ERR(inode)) {
 401                 ret = PTR_ERR(inode);
 402                 goto fail;
 403         }
 404         BUG_ON(!inode);
 405         d_instantiate(dentry, inode);
 406         ret = 0;
 407 fail:
 408         return ret;
 409 }
 410
 411 /* copy of may_create in fs/namei.c() */
 412 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 413 {
 414         if (child->d_inode)
 415                 return -EEXIST;
 416         if (IS_DEADDIR(dir))
 417                 return -ENOENT;
 418         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
 419 }
 420
 421 /*
 422  * Create a new subvolume below @parent.  This is largely modeled after
 423  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 424  * inside this filesystem so it's quite a bit simpler.
 425  */
 426 static noinline int btrfs_mksubvol(struct path *parent,
 427                                    char *name, int namelen,
 428                                    struct btrfs_root *snap_src)
 429 {
 430         struct inode *dir  = parent->dentry->d_inode;
 431         struct dentry *dentry;
 432         int error;
 433
 434         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 435
 436         dentry = lookup_one_len(name, parent->dentry, namelen);
 437         error = PTR_ERR(dentry);
 438         if (IS_ERR(dentry))
 439                 goto out_unlock;
 440
 441         error = -EEXIST;
 442         if (dentry->d_inode)
 443                 goto out_dput;
 444
 445         error = mnt_want_write(parent->mnt);
 446         if (error)
 447                 goto out_dput;
 448
 449         error = btrfs_may_create(dir, dentry);
 450         if (error)
 451                 goto out_drop_write;
 452
 453         down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
 454
 455         if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
 456                 goto out_up_read;
 457
 458         if (snap_src) {
 459                 error = create_snapshot(snap_src, dentry,
 460                                         name, namelen);
 461         } else {
 462                 error = create_subvol(BTRFS_I(dir)->root, dentry,
 463                                       name, namelen);
 464         }
 465         if (!error)
 466                 fsnotify_mkdir(dir, dentry);
 467 out_up_read:
 468         up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
 469 out_drop_write:
 470         mnt_drop_write(parent->mnt);
 471 out_dput:
 472         dput(dentry);
 473 out_unlock:
 474         mutex_unlock(&dir->i_mutex);
 475         return error;
 476 }
 477
 478 static int should_defrag_range(struct inode *inode, u64 start, u64 len,
 479                                u64 *last_len, u64 *skip, u64 *defrag_end)
 480 {
 481         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 482         struct extent_map *em = NULL;
 483         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 484         int ret = 1;
 485
 486         /*
 487          * make sure that once we start defragging and extent, we keep on
 488          * defragging it
 489          */
 490         if (start < *defrag_end)
 491                 return 1;
 492
 493         *skip = 0;
 494
 495         /*
 496          * hopefully we have this extent in the tree already, try without
 497          * the full extent lock
 498          */
 499         read_lock(&em_tree->lock);
 500         em = lookup_extent_mapping(em_tree, start, len);
 501         read_unlock(&em_tree->lock);
 502
 503         if (!em) {
 504                 /* get the big lock and read metadata off disk */
 505                 lock_extent(io_tree, start, start + len - 1, GFP_NOFS);
 506                 em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
 507                 unlock_extent(io_tree, start, start + len - 1, GFP_NOFS);
 508
 509                 if (!em)
 510                         return 0;
 511         }
 512
 513         /* this will cover holes, and inline extents */
 514         if (em->block_start >= EXTENT_MAP_LAST_BYTE)
 515                 ret = 0;
 516
 517         /*
 518          * we hit a real extent, if it is big don't bother defragging it again
 519          */
 520         if ((*last_len == 0 || *last_len >= 256 * 1024) &&
 521             em->len >= 256 * 1024)
 522                 ret = 0;
 523
 524         /*
 525          * last_len ends up being a counter of how many bytes we've defragged.
 526          * every time we choose not to defrag an extent, we reset *last_len
 527          * so that the next tiny extent will force a defrag.
 528          *
 529          * The end result of this is that tiny extents before a single big
 530          * extent will force at least part of that big extent to be defragged.
 531          */
 532         if (ret) {
 533                 *last_len += len;
 534                 *defrag_end = extent_map_end(em);
 535         } else {
 536                 *last_len = 0;
 537                 *skip = extent_map_end(em);
 538                 *defrag_end = 0;
 539         }
 540
 541         free_extent_map(em);
 542         return ret;
 543 }
 544
 545 static int btrfs_defrag_file(struct file *file)
 546 {
 547         struct inode *inode = fdentry(file)->d_inode;
 548         struct btrfs_root *root = BTRFS_I(inode)->root;
 549         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 550         struct btrfs_ordered_extent *ordered;
 551         struct page *page;
 552         unsigned long last_index;
 553         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 554         unsigned long total_read = 0;
 555         u64 page_start;
 556         u64 page_end;
 557         u64 last_len = 0;
 558         u64 skip = 0;
 559         u64 defrag_end = 0;
 560         unsigned long i;
 561         int ret;
 562
 563         if (inode->i_size == 0)
 564                 return 0;
 565
 566         last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
 567         i = 0;
 568         while (i <= last_index) {
 569                 if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
 570                                         PAGE_CACHE_SIZE, &last_len, &skip,
 571                                         &defrag_end)) {
 572                         unsigned long next;
 573                         /*
 574                          * the should_defrag function tells us how much to skip
 575                          * bump our counter by the suggested amount
 576                          */
 577                         next = (skip + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 578                         i = max(i + 1, next);
 579                         continue;
 580                 }
 581
 582                 if (total_read % ra_pages == 0) {
 583                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 584                                        min(last_index, i + ra_pages - 1));
 585                 }
 586                 total_read++;
 587                 mutex_lock(&inode->i_mutex);
 588
 589                 ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);
 590                 if (ret) {
 591                         ret = -ENOSPC;
 592                         break;
 593                 }
 594
 595                 ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
 596                 if (ret) {
 597                         btrfs_free_reserved_data_space(root, inode,
 598                                                        PAGE_CACHE_SIZE);
 599                         ret = -ENOSPC;
 600                         break;
 601                 }
 602 again:
 603                 if (inode->i_size == 0 ||
 604                     i > ((inode->i_size - 1) >> PAGE_CACHE_SHIFT)) {
 605                         ret = 0;
 606                         goto err_reservations;
 607                 }
 608
 609                 page = grab_cache_page(inode->i_mapping, i);
 610                 if (!page)
 611                         goto err_reservations;
 612
 613                 if (!PageUptodate(page)) {
 614                         btrfs_readpage(NULL, page);
 615                         lock_page(page);
 616                         if (!PageUptodate(page)) {
 617                                 unlock_page(page);
 618                                 page_cache_release(page);
 619                                 goto err_reservations;
 620                         }
 621                 }
 622
 623                 if (page->mapping != inode->i_mapping) {
 624                         unlock_page(page);
 625                         page_cache_release(page);
 626                         goto again;
 627                 }
 628
 629                 wait_on_page_writeback(page);
 630
 631                 if (PageDirty(page)) {
 632                         btrfs_free_reserved_data_space(root, inode,
 633                                                        PAGE_CACHE_SIZE);
 634                         goto loop_unlock;
 635                 }
 636
 637                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 638                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 639                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 640
 641                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
 642                 if (ordered) {
 643                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 644                         unlock_page(page);
 645                         page_cache_release(page);
 646                         btrfs_start_ordered_extent(inode, ordered, 1);
 647                         btrfs_put_ordered_extent(ordered);
 648                         goto again;
 649                 }
 650                 set_page_extent_mapped(page);
 651
 652                 /*
 653                  * this makes sure page_mkwrite is called on the
 654                  * page if it is dirtied again later
 655                  */
 656                 clear_page_dirty_for_io(page);
 657                 clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start,
 658                                   page_end, EXTENT_DIRTY | EXTENT_DELALLOC |
 659                                   EXTENT_DO_ACCOUNTING, GFP_NOFS);
 660
 661                 btrfs_set_extent_delalloc(inode, page_start, page_end);
 662                 ClearPageChecked(page);
 663                 set_page_dirty(page);
 664                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 665
 666 loop_unlock:
 667                 unlock_page(page);
 668                 page_cache_release(page);
 669                 mutex_unlock(&inode->i_mutex);
 670
 671                 btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
 672                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 673                 i++;
 674         }
 675
 676         return 0;
 677
 678 err_reservations:
 679         mutex_unlock(&inode->i_mutex);
 680         btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
 681         btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
 682         return ret;
 683 }
 684
 685 static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 686                                         void __user *arg)
 687 {
 688         u64 new_size;
 689         u64 old_size;
 690         u64 devid = 1;
 691         struct btrfs_ioctl_vol_args *vol_args;
 692         struct btrfs_trans_handle *trans;
 693         struct btrfs_device *device = NULL;
 694         char *sizestr;
 695         char *devstr = NULL;
 696         int ret = 0;
 697         int namelen;
 698         int mod = 0;
 699
 700         if (root->fs_info->sb->s_flags & MS_RDONLY)
 701                 return -EROFS;
 702
 703         if (!capable(CAP_SYS_ADMIN))
 704                 return -EPERM;
 705
 706         vol_args = memdup_user(arg, sizeof(*vol_args));
 707         if (IS_ERR(vol_args))
 708                 return PTR_ERR(vol_args);
 709
 710         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 711         namelen = strlen(vol_args->name);
 712
 713         mutex_lock(&root->fs_info->volume_mutex);
 714         sizestr = vol_args->name;
 715         devstr = strchr(sizestr, ':');
 716         if (devstr) {
 717                 char *end;
 718                 sizestr = devstr + 1;
 719                 *devstr = '\0';
 720                 devstr = vol_args->name;
 721                 devid = simple_strtoull(devstr, &end, 10);
 722                 printk(KERN_INFO "resizing devid %llu\n",
 723                        (unsigned long long)devid);
 724         }
 725         device = btrfs_find_device(root, devid, NULL, NULL);
 726         if (!device) {
 727                 printk(KERN_INFO "resizer unable to find device %llu\n",
 728                        (unsigned long long)devid);
 729                 ret = -EINVAL;
 730                 goto out_unlock;
 731         }
 732         if (!strcmp(sizestr, "max"))
 733                 new_size = device->bdev->bd_inode->i_size;
 734         else {
 735                 if (sizestr[0] == '-') {
 736                         mod = -1;
 737                         sizestr++;
 738                 } else if (sizestr[0] == '+') {
 739                         mod = 1;
 740                         sizestr++;
 741                 }
 742                 new_size = btrfs_parse_size(sizestr);
 743                 if (new_size == 0) {
 744                         ret = -EINVAL;
 745                         goto out_unlock;
 746                 }
 747         }
 748
 749         old_size = device->total_bytes;
 750
 751         if (mod < 0) {
 752                 if (new_size > old_size) {
 753                         ret = -EINVAL;
 754                         goto out_unlock;
 755                 }
 756                 new_size = old_size - new_size;
 757         } else if (mod > 0) {
 758                 new_size = old_size + new_size;
 759         }
 760
 761         if (new_size < 256 * 1024 * 1024) {
 762                 ret = -EINVAL;
 763                 goto out_unlock;
 764         }
 765         if (new_size > device->bdev->bd_inode->i_size) {
 766                 ret = -EFBIG;
 767                 goto out_unlock;
 768         }
 769
 770         do_div(new_size, root->sectorsize);
 771         new_size *= root->sectorsize;
 772
 773         printk(KERN_INFO "new size for %s is %llu\n",
 774                 device->name, (unsigned long long)new_size);
 775
 776         if (new_size > old_size) {
 777                 trans = btrfs_start_transaction(root, 1);
 778                 ret = btrfs_grow_device(trans, device, new_size);
 779                 btrfs_commit_transaction(trans, root);
 780         } else {
 781                 ret = btrfs_shrink_device(device, new_size);
 782         }
 783
 784 out_unlock:
 785         mutex_unlock(&root->fs_info->volume_mutex);
 786         kfree(vol_args);
 787         return ret;
 788 }
 789
 790 static noinline int btrfs_ioctl_snap_create(struct file *file,
 791                                             void __user *arg, int subvol)
 792 {
 793         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 794         struct btrfs_ioctl_vol_args *vol_args;
 795         struct file *src_file;
 796         int namelen;
 797         int ret = 0;
 798
 799         if (root->fs_info->sb->s_flags & MS_RDONLY)
 800                 return -EROFS;
 801
 802         vol_args = memdup_user(arg, sizeof(*vol_args));
 803         if (IS_ERR(vol_args))
 804                 return PTR_ERR(vol_args);
 805
 806         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 807         namelen = strlen(vol_args->name);
 808         if (strchr(vol_args->name, '/')) {
 809                 ret = -EINVAL;
 810                 goto out;
 811         }
 812
 813         if (subvol) {
 814                 ret = btrfs_mksubvol(&file->f_path, vol_args->name, namelen,
 815                                      NULL);
 816         } else {
 817                 struct inode *src_inode;
 818                 src_file = fget(vol_args->fd);
 819                 if (!src_file) {
 820                         ret = -EINVAL;
 821                         goto out;
 822                 }
 823
 824                 src_inode = src_file->f_path.dentry->d_inode;
 825                 if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
 826                         printk(KERN_INFO "btrfs: Snapshot src from "
 827                                "another FS\n");
 828                         ret = -EINVAL;
 829                         fput(src_file);
 830                         goto out;
 831                 }
 832                 ret = btrfs_mksubvol(&file->f_path, vol_args->name, namelen,
 833                                      BTRFS_I(src_inode)->root);
 834                 fput(src_file);
 835         }
 836 out:
 837         kfree(vol_args);
 838         return ret;
 839 }
 840
 841 /*
 842  * helper to check if the subvolume references other subvolumes
 843  */
 844 static noinline int may_destroy_subvol(struct btrfs_root *root)
 845 {
 846         struct btrfs_path *path;
 847         struct btrfs_key key;
 848         int ret;
 849
 850         path = btrfs_alloc_path();
 851         if (!path)
 852                 return -ENOMEM;
 853
 854         key.objectid = root->root_key.objectid;
 855         key.type = BTRFS_ROOT_REF_KEY;
 856         key.offset = (u64)-1;
 857
 858         ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
 859                                 &key, path, 0, 0);
 860         if (ret < 0)
 861                 goto out;
 862         BUG_ON(ret == 0);
 863
 864         ret = 0;
 865         if (path->slots[0] > 0) {
 866                 path->slots[0]--;
 867                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 868                 if (key.objectid == root->root_key.objectid &&
 869                     key.type == BTRFS_ROOT_REF_KEY)
 870                         ret = -ENOTEMPTY;
 871         }
 872 out:
 873         btrfs_free_path(path);
 874         return ret;
 875 }
 876
 877 static noinline int key_in_sk(struct btrfs_key *key,
 878                               struct btrfs_ioctl_search_key *sk)
 879 {
 880         if (key->objectid < sk->min_objectid)
 881                 return 0;
 882         if (key->offset < sk->min_offset)
 883                 return 0;
 884         if (key->type < sk->min_type)
 885                 return 0;
 886         if (key->objectid > sk->max_objectid)
 887                 return 0;
 888         if (key->type > sk->max_type)
 889                 return 0;
 890         if (key->offset > sk->max_offset)
 891                 return 0;
 892         return 1;
 893 }
 894
 895 static noinline int copy_to_sk(struct btrfs_root *root,
 896                                struct btrfs_path *path,
 897                                struct btrfs_key *key,
 898                                struct btrfs_ioctl_search_key *sk,
 899                                char *buf,
 900                                unsigned long *sk_offset,
 901                                int *num_found)
 902 {
 903         u64 found_transid;
 904         struct extent_buffer *leaf;
 905         struct btrfs_ioctl_search_header sh;
 906         unsigned long item_off;
 907         unsigned long item_len;
 908         int nritems;
 909         int i;
 910         int slot;
 911         int found = 0;
 912         int ret = 0;
 913
 914         leaf = path->nodes[0];
 915         slot = path->slots[0];
 916         nritems = btrfs_header_nritems(leaf);
 917
 918         if (btrfs_header_generation(leaf) > sk->max_transid) {
 919                 i = nritems;
 920                 goto advance_key;
 921         }
 922         found_transid = btrfs_header_generation(leaf);
 923
 924         for (i = slot; i < nritems; i++) {
 925                 item_off = btrfs_item_ptr_offset(leaf, i);
 926                 item_len = btrfs_item_size_nr(leaf, i);
 927
 928                 if (item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
 929                         item_len = 0;
 930
 931                 if (sizeof(sh) + item_len + *sk_offset >
 932                     BTRFS_SEARCH_ARGS_BUFSIZE) {
 933                         ret = 1;
 934                         goto overflow;
 935                 }
 936
 937                 btrfs_item_key_to_cpu(leaf, key, i);
 938                 if (!key_in_sk(key, sk))
 939                         continue;
 940
 941                 sh.objectid = key->objectid;
 942                 sh.offset = key->offset;
 943                 sh.type = key->type;
 944                 sh.len = item_len;
 945                 sh.transid = found_transid;
 946
 947                 /* copy search result header */
 948                 memcpy(buf + *sk_offset, &sh, sizeof(sh));
 949                 *sk_offset += sizeof(sh);
 950
 951                 if (item_len) {
 952                         char *p = buf + *sk_offset;
 953                         /* copy the item */
 954                         read_extent_buffer(leaf, p,
 955                                            item_off, item_len);
 956                         *sk_offset += item_len;
 957                         found++;
 958                 }
 959
 960                 if (*num_found >= sk->nr_items)
 961                         break;
 962         }
 963 advance_key:
 964         if (key->offset < (u64)-1)
 965                 key->offset++;
 966         else if (key->type < (u64)-1)
 967                 key->type++;
 968         else if (key->objectid < (u64)-1)
 969                 key->objectid++;
 970         ret = 0;
 971 overflow:
 972         *num_found += found;
 973         return ret;
 974 }
 975
 976 static noinline int search_ioctl(struct inode *inode,
 977                                  struct btrfs_ioctl_search_args *args)
 978 {
 979         struct btrfs_root *root;
 980         struct btrfs_key key;
 981         struct btrfs_key max_key;
 982         struct btrfs_path *path;
 983         struct btrfs_ioctl_search_key *sk = &args->key;
 984         struct btrfs_fs_info *info = BTRFS_I(inode)->root->fs_info;
 985         int ret;
 986         int num_found = 0;
 987         unsigned long sk_offset = 0;
 988
 989         path = btrfs_alloc_path();
 990         if (!path)
 991                 return -ENOMEM;
 992
 993         if (sk->tree_id == 0) {
 994                 /* search the root of the inode that was passed */
 995                 root = BTRFS_I(inode)->root;
 996         } else {
 997                 key.objectid = sk->tree_id;
 998                 key.type = BTRFS_ROOT_ITEM_KEY;
 999                 key.offset = (u64)-1;
1000                 root = btrfs_read_fs_root_no_name(info, &key);
1001                 if (IS_ERR(root)) {
1002                         printk(KERN_ERR "could not find root %llu\n",
1003                                sk->tree_id);
1004                         btrfs_free_path(path);
1005                         return -ENOENT;
1006                 }
1007         }
1008
1009         key.objectid = sk->min_objectid;
1010         key.type = sk->min_type;
1011         key.offset = sk->min_offset;
1012
1013         max_key.objectid = sk->max_objectid;
1014         max_key.type = sk->max_type;
1015         max_key.offset = sk->max_offset;
1016
1017         path->keep_locks = 1;
1018
1019         while(1) {
1020                 ret = btrfs_search_forward(root, &key, &max_key, path, 0,
1021                                            sk->min_transid);
1022                 if (ret != 0) {
1023                         if (ret > 0)
1024                                 ret = 0;
1025                         goto err;
1026                 }
1027                 ret = copy_to_sk(root, path, &key, sk, args->buf,
1028                                  &sk_offset, &num_found);
1029                 btrfs_release_path(root, path);
1030                 if (ret || num_found >= sk->nr_items)
1031                         break;
1032
1033         }
1034         ret = 0;
1035 err:
1036         sk->nr_items = num_found;
1037         btrfs_free_path(path);
1038         return ret;
1039 }
1040
1041 static noinline int btrfs_ioctl_tree_search(struct file *file,
1042                                            void __user *argp)
1043 {
1044          struct btrfs_ioctl_search_args *args;
1045          struct inode *inode;
1046          int ret;
1047
1048         if (!capable(CAP_SYS_ADMIN))
1049                 return -EPERM;
1050
1051         args = kmalloc(sizeof(*args), GFP_KERNEL);
1052         if (!args)
1053                 return -ENOMEM;
1054
1055         if (copy_from_user(args, argp, sizeof(*args))) {
1056                 kfree(args);
1057                 return -EFAULT;
1058         }
1059         inode = fdentry(file)->d_inode;
1060         ret = search_ioctl(inode, args);
1061         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
1062                 ret = -EFAULT;
1063         kfree(args);
1064         return ret;
1065 }
1066
1067 /*
1068  * Search INODE_REFs to identify path name of 'dirid' directory
1069  * in a 'tree_id' tree. and sets path name to 'name'.
1070  */
1071 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
1072                                 u64 tree_id, u64 dirid, char *name)
1073 {
1074         struct btrfs_root *root;
1075         struct btrfs_key key;
1076         char *ptr;
1077         int ret = -1;
1078         int slot;
1079         int len;
1080         int total_len = 0;
1081         struct btrfs_inode_ref *iref;
1082         struct extent_buffer *l;
1083         struct btrfs_path *path;
1084
1085         if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
1086                 name[0]='\0';
1087                 return 0;
1088         }
1089
1090         path = btrfs_alloc_path();
1091         if (!path)
1092                 return -ENOMEM;
1093
1094         ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];
1095
1096         key.objectid = tree_id;
1097         key.type = BTRFS_ROOT_ITEM_KEY;
1098         key.offset = (u64)-1;
1099         root = btrfs_read_fs_root_no_name(info, &key);
1100         if (IS_ERR(root)) {
1101                 printk(KERN_ERR "could not find root %llu\n", tree_id);
1102                 return -ENOENT;
1103         }
1104
1105         key.objectid = dirid;
1106         key.type = BTRFS_INODE_REF_KEY;
1107         key.offset = 0;
1108
1109         while(1) {
1110                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1111                 if (ret < 0)
1112                         goto out;
1113
1114                 l = path->nodes[0];
1115                 slot = path->slots[0];
1116                 btrfs_item_key_to_cpu(l, &key, slot);
1117
1118                 if (ret > 0 && (key.objectid != dirid ||
1119                                 key.type != BTRFS_INODE_REF_KEY)) {
1120                         ret = -ENOENT;
1121                         goto out;
1122                 }
1123
1124                 iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
1125                 len = btrfs_inode_ref_name_len(l, iref);
1126                 ptr -= len + 1;
1127                 total_len += len + 1;
1128                 if (ptr < name)
1129                         goto out;
1130
1131                 *(ptr + len) = '/';
1132                 read_extent_buffer(l, ptr,(unsigned long)(iref + 1), len);
1133
1134                 if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
1135                         break;
1136
1137                 btrfs_release_path(root, path);
1138                 key.objectid = key.offset;
1139                 key.offset = 0;
1140                 dirid = key.objectid;
1141
1142         }
1143         if (ptr < name)
1144                 goto out;
1145         memcpy(name, ptr, total_len);
1146         name[total_len]='\0';
1147         ret = 0;
1148 out:
1149         btrfs_free_path(path);
1150         return ret;
1151 }
1152
1153 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
1154                                            void __user *argp)
1155 {
1156          struct btrfs_ioctl_ino_lookup_args *args;
1157          struct inode *inode;
1158          int ret;
1159
1160         if (!capable(CAP_SYS_ADMIN))
1161                 return -EPERM;
1162
1163         args = kmalloc(sizeof(*args), GFP_KERNEL);
1164         if (copy_from_user(args, argp, sizeof(*args))) {
1165                 kfree(args);
1166                 return -EFAULT;
1167         }
1168         inode = fdentry(file)->d_inode;
1169
1170         ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
1171                                         args->treeid, args->objectid,
1172                                         args->name);
1173
1174         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
1175                 ret = -EFAULT;
1176
1177         kfree(args);
1178         return ret;
1179 }
1180
1181 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
1182                                              void __user *arg)
1183 {
1184         struct dentry *parent = fdentry(file);
1185         struct dentry *dentry;
1186         struct inode *dir = parent->d_inode;
1187         struct inode *inode;
1188         struct btrfs_root *root = BTRFS_I(dir)->root;
1189         struct btrfs_root *dest = NULL;
1190         struct btrfs_ioctl_vol_args *vol_args;
1191         struct btrfs_trans_handle *trans;
1192         int namelen;
1193         int ret;
1194         int err = 0;
1195
1196         if (!capable(CAP_SYS_ADMIN))
1197                 return -EPERM;
1198
1199         vol_args = memdup_user(arg, sizeof(*vol_args));
1200         if (IS_ERR(vol_args))
1201                 return PTR_ERR(vol_args);
1202
1203         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1204         namelen = strlen(vol_args->name);
1205         if (strchr(vol_args->name, '/') ||
1206             strncmp(vol_args->name, "..", namelen) == 0) {
1207                 err = -EINVAL;
1208                 goto out;
1209         }
1210
1211         err = mnt_want_write(file->f_path.mnt);
1212         if (err)
1213                 goto out;
1214
1215         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
1216         dentry = lookup_one_len(vol_args->name, parent, namelen);
1217         if (IS_ERR(dentry)) {
1218                 err = PTR_ERR(dentry);
1219                 goto out_unlock_dir;
1220         }
1221
1222         if (!dentry->d_inode) {
1223                 err = -ENOENT;
1224                 goto out_dput;
1225         }
1226
1227         inode = dentry->d_inode;
1228         if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
1229                 err = -EINVAL;
1230                 goto out_dput;
1231         }
1232
1233         dest = BTRFS_I(inode)->root;
1234
1235         mutex_lock(&inode->i_mutex);
1236         err = d_invalidate(dentry);
1237         if (err)
1238                 goto out_unlock;
1239
1240         down_write(&root->fs_info->subvol_sem);
1241
1242         err = may_destroy_subvol(dest);
1243         if (err)
1244                 goto out_up_write;
1245
1246         trans = btrfs_start_transaction(root, 1);
1247         ret = btrfs_unlink_subvol(trans, root, dir,
1248                                 dest->root_key.objectid,
1249                                 dentry->d_name.name,
1250                                 dentry->d_name.len);
1251         BUG_ON(ret);
1252
1253         btrfs_record_root_in_trans(trans, dest);
1254
1255         memset(&dest->root_item.drop_progress, 0,
1256                 sizeof(dest->root_item.drop_progress));
1257         dest->root_item.drop_level = 0;
1258         btrfs_set_root_refs(&dest->root_item, 0);
1259
1260         ret = btrfs_insert_orphan_item(trans,
1261                                 root->fs_info->tree_root,
1262                                 dest->root_key.objectid);
1263         BUG_ON(ret);
1264
1265         ret = btrfs_commit_transaction(trans, root);
1266         BUG_ON(ret);
1267         inode->i_flags |= S_DEAD;
1268 out_up_write:
1269         up_write(&root->fs_info->subvol_sem);
1270 out_unlock:
1271         mutex_unlock(&inode->i_mutex);
1272         if (!err) {
1273                 shrink_dcache_sb(root->fs_info->sb);
1274                 btrfs_invalidate_inodes(dest);
1275                 d_delete(dentry);
1276         }
1277 out_dput:
1278         dput(dentry);
1279 out_unlock_dir:
1280         mutex_unlock(&dir->i_mutex);
1281         mnt_drop_write(file->f_path.mnt);
1282 out:
1283         kfree(vol_args);
1284         return err;
1285 }
1286
1287 static int btrfs_ioctl_defrag(struct file *file)
1288 {
1289         struct inode *inode = fdentry(file)->d_inode;
1290         struct btrfs_root *root = BTRFS_I(inode)->root;
1291         int ret;
1292
1293         ret = mnt_want_write(file->f_path.mnt);
1294         if (ret)
1295                 return ret;
1296
1297         switch (inode->i_mode & S_IFMT) {
1298         case S_IFDIR:
1299                 if (!capable(CAP_SYS_ADMIN)) {
1300                         ret = -EPERM;
1301                         goto out;
1302                 }
1303                 btrfs_defrag_root(root, 0);
1304                 btrfs_defrag_root(root->fs_info->extent_root, 0);
1305                 break;
1306         case S_IFREG:
1307                 if (!(file->f_mode & FMODE_WRITE)) {
1308                         ret = -EINVAL;
1309                         goto out;
1310                 }
1311                 btrfs_defrag_file(file);
1312                 break;
1313         }
1314 out:
1315         mnt_drop_write(file->f_path.mnt);
1316         return ret;
1317 }
1318
1319 static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
1320 {
1321         struct btrfs_ioctl_vol_args *vol_args;
1322         int ret;
1323
1324         if (!capable(CAP_SYS_ADMIN))
1325                 return -EPERM;
1326
1327         vol_args = memdup_user(arg, sizeof(*vol_args));
1328         if (IS_ERR(vol_args))
1329                 return PTR_ERR(vol_args);
1330
1331         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1332         ret = btrfs_init_new_device(root, vol_args->name);
1333
1334         kfree(vol_args);
1335         return ret;
1336 }
1337
1338 static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
1339 {
1340         struct btrfs_ioctl_vol_args *vol_args;
1341         int ret;
1342
1343         if (!capable(CAP_SYS_ADMIN))
1344                 return -EPERM;
1345
1346         if (root->fs_info->sb->s_flags & MS_RDONLY)
1347                 return -EROFS;
1348
1349         vol_args = memdup_user(arg, sizeof(*vol_args));
1350         if (IS_ERR(vol_args))
1351                 return PTR_ERR(vol_args);
1352
1353         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1354         ret = btrfs_rm_device(root, vol_args->name);
1355
1356         kfree(vol_args);
1357         return ret;
1358 }
1359
1360 static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
1361                                        u64 off, u64 olen, u64 destoff)
1362 {
1363         struct inode *inode = fdentry(file)->d_inode;
1364         struct btrfs_root *root = BTRFS_I(inode)->root;
1365         struct file *src_file;
1366         struct inode *src;
1367         struct btrfs_trans_handle *trans;
1368         struct btrfs_path *path;
1369         struct extent_buffer *leaf;
1370         char *buf;
1371         struct btrfs_key key;
1372         u32 nritems;
1373         int slot;
1374         int ret;
1375         u64 len = olen;
1376         u64 bs = root->fs_info->sb->s_blocksize;
1377         u64 hint_byte;
1378
1379         /*
1380          * TODO:
1381          * - split compressed inline extents.  annoying: we need to
1382          *   decompress into destination's address_space (the file offset
1383          *   may change, so source mapping won't do), then recompress (or
1384          *   otherwise reinsert) a subrange.
1385          * - allow ranges within the same file to be cloned (provided
1386          *   they don't overlap)?
1387          */
1388
1389         /* the destination must be opened for writing */
1390         if (!(file->f_mode & FMODE_WRITE))
1391                 return -EINVAL;
1392
1393         ret = mnt_want_write(file->f_path.mnt);
1394         if (ret)
1395                 return ret;
1396
1397         src_file = fget(srcfd);
1398         if (!src_file) {
1399                 ret = -EBADF;
1400                 goto out_drop_write;
1401         }
1402         src = src_file->f_dentry->d_inode;
1403
1404         ret = -EINVAL;
1405         if (src == inode)
1406                 goto out_fput;
1407
1408         ret = -EISDIR;
1409         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
1410                 goto out_fput;
1411
1412         ret = -EXDEV;
1413         if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
1414                 goto out_fput;
1415
1416         ret = -ENOMEM;
1417         buf = vmalloc(btrfs_level_size(root, 0));
1418         if (!buf)
1419                 goto out_fput;
1420
1421         path = btrfs_alloc_path();
1422         if (!path) {
1423                 vfree(buf);
1424                 goto out_fput;
1425         }
1426         path->reada = 2;
1427
1428         if (inode < src) {
1429                 mutex_lock(&inode->i_mutex);
1430                 mutex_lock(&src->i_mutex);
1431         } else {
1432                 mutex_lock(&src->i_mutex);
1433                 mutex_lock(&inode->i_mutex);
1434         }
1435
1436         /* determine range to clone */
1437         ret = -EINVAL;
1438         if (off >= src->i_size || off + len > src->i_size)
1439                 goto out_unlock;
1440         if (len == 0)
1441                 olen = len = src->i_size - off;
1442         /* if we extend to eof, continue to block boundary */
1443         if (off + len == src->i_size)
1444                 len = ((src->i_size + bs-1) & ~(bs-1))
1445                         - off;
1446
1447         /* verify the end result is block aligned */
1448         if ((off & (bs-1)) ||
1449             ((off + len) & (bs-1)))
1450                 goto out_unlock;
1451
1452         /* do any pending delalloc/csum calc on src, one way or
1453            another, and lock file content */
1454         while (1) {
1455                 struct btrfs_ordered_extent *ordered;
1456                 lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1457                 ordered = btrfs_lookup_first_ordered_extent(inode, off+len);
1458                 if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
1459                         break;
1460                 unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1461                 if (ordered)
1462                         btrfs_put_ordered_extent(ordered);
1463                 btrfs_wait_ordered_range(src, off, off+len);
1464         }
1465
1466         trans = btrfs_start_transaction(root, 1);
1467         BUG_ON(!trans);
1468
1469         /* punch hole in destination first */
1470         btrfs_drop_extents(trans, inode, off, off + len, &hint_byte, 1);
1471
1472         /* clone data */
1473         key.objectid = src->i_ino;
1474         key.type = BTRFS_EXTENT_DATA_KEY;
1475         key.offset = 0;
1476
1477         while (1) {
1478                 /*
1479                  * note the key will change type as we walk through the
1480                  * tree.
1481                  */
1482                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
1483                 if (ret < 0)
1484                         goto out;
1485
1486                 nritems = btrfs_header_nritems(path->nodes[0]);
1487                 if (path->slots[0] >= nritems) {
1488                         ret = btrfs_next_leaf(root, path);
1489                         if (ret < 0)
1490                                 goto out;
1491                         if (ret > 0)
1492                                 break;
1493                         nritems = btrfs_header_nritems(path->nodes[0]);
1494                 }
1495                 leaf = path->nodes[0];
1496                 slot = path->slots[0];
1497
1498                 btrfs_item_key_to_cpu(leaf, &key, slot);
1499                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
1500                     key.objectid != src->i_ino)
1501                         break;
1502
1503                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
1504                         struct btrfs_file_extent_item *extent;
1505                         int type;
1506                         u32 size;
1507                         struct btrfs_key new_key;
1508                         u64 disko = 0, diskl = 0;
1509                         u64 datao = 0, datal = 0;
1510                         u8 comp;
1511
1512                         size = btrfs_item_size_nr(leaf, slot);
1513                         read_extent_buffer(leaf, buf,
1514                                            btrfs_item_ptr_offset(leaf, slot),
1515                                            size);
1516
1517                         extent = btrfs_item_ptr(leaf, slot,
1518                                                 struct btrfs_file_extent_item);
1519                         comp = btrfs_file_extent_compression(leaf, extent);
1520                         type = btrfs_file_extent_type(leaf, extent);
1521                         if (type == BTRFS_FILE_EXTENT_REG ||
1522                             type == BTRFS_FILE_EXTENT_PREALLOC) {
1523                                 disko = btrfs_file_extent_disk_bytenr(leaf,
1524                                                                       extent);
1525                                 diskl = btrfs_file_extent_disk_num_bytes(leaf,
1526                                                                  extent);
1527                                 datao = btrfs_file_extent_offset(leaf, extent);
1528                                 datal = btrfs_file_extent_num_bytes(leaf,
1529                                                                     extent);
1530                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1531                                 /* take upper bound, may be compressed */
1532                                 datal = btrfs_file_extent_ram_bytes(leaf,
1533                                                                     extent);
1534                         }
1535                         btrfs_release_path(root, path);
1536
1537                         if (key.offset + datal < off ||
1538                             key.offset >= off+len)
1539                                 goto next;
1540
1541                         memcpy(&new_key, &key, sizeof(new_key));
1542                         new_key.objectid = inode->i_ino;
1543                         new_key.offset = key.offset + destoff - off;
1544
1545                         if (type == BTRFS_FILE_EXTENT_REG ||
1546                             type == BTRFS_FILE_EXTENT_PREALLOC) {
1547                                 ret = btrfs_insert_empty_item(trans, root, path,
1548                                                               &new_key, size);
1549                                 if (ret)
1550                                         goto out;
1551
1552                                 leaf = path->nodes[0];
1553                                 slot = path->slots[0];
1554                                 write_extent_buffer(leaf, buf,
1555                                             btrfs_item_ptr_offset(leaf, slot),
1556                                             size);
1557
1558                                 extent = btrfs_item_ptr(leaf, slot,
1559                                                 struct btrfs_file_extent_item);
1560
1561                                 if (off > key.offset) {
1562                                         datao += off - key.offset;
1563                                         datal -= off - key.offset;
1564                                 }
1565
1566                                 if (key.offset + datal > off + len)
1567                                         datal = off + len - key.offset;
1568
1569                                 /* disko == 0 means it's a hole */
1570                                 if (!disko)
1571                                         datao = 0;
1572
1573                                 btrfs_set_file_extent_offset(leaf, extent,
1574                                                              datao);
1575                                 btrfs_set_file_extent_num_bytes(leaf, extent,
1576                                                                 datal);
1577                                 if (disko) {
1578                                         inode_add_bytes(inode, datal);
1579                                         ret = btrfs_inc_extent_ref(trans, root,
1580                                                         disko, diskl, 0,
1581                                                         root->root_key.objectid,
1582                                                         inode->i_ino,
1583                                                         new_key.offset - datao);
1584                                         BUG_ON(ret);
1585                                 }
1586                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1587                                 u64 skip = 0;
1588                                 u64 trim = 0;
1589                                 if (off > key.offset) {
1590                                         skip = off - key.offset;
1591                                         new_key.offset += skip;
1592                                 }
1593
1594                                 if (key.offset + datal > off+len)
1595                                         trim = key.offset + datal - (off+len);
1596
1597                                 if (comp && (skip || trim)) {
1598                                         ret = -EINVAL;
1599                                         goto out;
1600                                 }
1601                                 size -= skip + trim;
1602                                 datal -= skip + trim;
1603                                 ret = btrfs_insert_empty_item(trans, root, path,
1604                                                               &new_key, size);
1605                                 if (ret)
1606                                         goto out;
1607
1608                                 if (skip) {
1609                                         u32 start =
1610                                           btrfs_file_extent_calc_inline_size(0);
1611                                         memmove(buf+start, buf+start+skip,
1612                                                 datal);
1613                                 }
1614
1615                                 leaf = path->nodes[0];
1616                                 slot = path->slots[0];
1617                                 write_extent_buffer(leaf, buf,
1618                                             btrfs_item_ptr_offset(leaf, slot),
1619                                             size);
1620                                 inode_add_bytes(inode, datal);
1621                         }
1622
1623                         btrfs_mark_buffer_dirty(leaf);
1624                 }
1625
1626 next:
1627                 btrfs_release_path(root, path);
1628                 key.offset++;
1629         }
1630         ret = 0;
1631 out:
1632         btrfs_release_path(root, path);
1633         if (ret == 0) {
1634                 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1635                 if (destoff + olen > inode->i_size)
1636                         btrfs_i_size_write(inode, destoff + olen);
1637                 BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
1638                 ret = btrfs_update_inode(trans, root, inode);
1639         }
1640         btrfs_end_transaction(trans, root);
1641         unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1642         if (ret)
1643                 vmtruncate(inode, 0);
1644 out_unlock:
1645         mutex_unlock(&src->i_mutex);
1646         mutex_unlock(&inode->i_mutex);
1647         vfree(buf);
1648         btrfs_free_path(path);
1649 out_fput:
1650         fput(src_file);
1651 out_drop_write:
1652         mnt_drop_write(file->f_path.mnt);
1653         return ret;
1654 }
1655
1656 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
1657 {
1658         struct btrfs_ioctl_clone_range_args args;
1659
1660         if (copy_from_user(&args, argp, sizeof(args)))
1661                 return -EFAULT;
1662         return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
1663                                  args.src_length, args.dest_offset);
1664 }
1665
1666 /*
1667  * there are many ways the trans_start and trans_end ioctls can lead
1668  * to deadlocks.  They should only be used by applications that
1669  * basically own the machine, and have a very in depth understanding
1670  * of all the possible deadlocks and enospc problems.
1671  */
1672 static long btrfs_ioctl_trans_start(struct file *file)
1673 {
1674         struct inode *inode = fdentry(file)->d_inode;
1675         struct btrfs_root *root = BTRFS_I(inode)->root;
1676         struct btrfs_trans_handle *trans;
1677         int ret;
1678
1679         ret = -EPERM;
1680         if (!capable(CAP_SYS_ADMIN))
1681                 goto out;
1682
1683         ret = -EINPROGRESS;
1684         if (file->private_data)
1685                 goto out;
1686
1687         ret = mnt_want_write(file->f_path.mnt);
1688         if (ret)
1689                 goto out;
1690
1691         mutex_lock(&root->fs_info->trans_mutex);
1692         root->fs_info->open_ioctl_trans++;
1693         mutex_unlock(&root->fs_info->trans_mutex);
1694
1695         ret = -ENOMEM;
1696         trans = btrfs_start_ioctl_transaction(root, 0);
1697         if (!trans)
1698                 goto out_drop;
1699
1700         file->private_data = trans;
1701         return 0;
1702
1703 out_drop:
1704         mutex_lock(&root->fs_info->trans_mutex);
1705         root->fs_info->open_ioctl_trans--;
1706         mutex_unlock(&root->fs_info->trans_mutex);
1707         mnt_drop_write(file->f_path.mnt);
1708 out:
1709         return ret;
1710 }
1711
1712 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
1713 {
1714         struct inode *inode = fdentry(file)->d_inode;
1715         struct btrfs_root *root = BTRFS_I(inode)->root;
1716         struct btrfs_root *new_root;
1717         struct btrfs_dir_item *di;
1718         struct btrfs_trans_handle *trans;
1719         struct btrfs_path *path;
1720         struct btrfs_key location;
1721         struct btrfs_disk_key disk_key;
1722         struct btrfs_super_block *disk_super;
1723         u64 features;
1724         u64 objectid = 0;
1725         u64 dir_id;
1726
1727         if (!capable(CAP_SYS_ADMIN))
1728                 return -EPERM;
1729
1730         if (copy_from_user(&objectid, argp, sizeof(objectid)))
1731                 return -EFAULT;
1732
1733         if (!objectid)
1734                 objectid = root->root_key.objectid;
1735
1736         location.objectid = objectid;
1737         location.type = BTRFS_ROOT_ITEM_KEY;
1738         location.offset = (u64)-1;
1739
1740         new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
1741         if (IS_ERR(new_root))
1742                 return PTR_ERR(new_root);
1743
1744         if (btrfs_root_refs(&new_root->root_item) == 0)
1745                 return -ENOENT;
1746
1747         path = btrfs_alloc_path();
1748         if (!path)
1749                 return -ENOMEM;
1750         path->leave_spinning = 1;
1751
1752         trans = btrfs_start_transaction(root, 1);
1753         if (!trans) {
1754                 btrfs_free_path(path);
1755                 return -ENOMEM;
1756         }
1757
1758         dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
1759         di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
1760                                    dir_id, "default", 7, 1);
1761         if (!di) {
1762                 btrfs_free_path(path);
1763                 btrfs_end_transaction(trans, root);
1764                 printk(KERN_ERR "Umm, you don't have the default dir item, "
1765                        "this isn't going to work\n");
1766                 return -ENOENT;
1767         }
1768
1769         btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
1770         btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
1771         btrfs_mark_buffer_dirty(path->nodes[0]);
1772         btrfs_free_path(path);
1773
1774         disk_super = &root->fs_info->super_copy;
1775         features = btrfs_super_incompat_flags(disk_super);
1776         if (!(features & BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL)) {
1777                 features |= BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL;
1778                 btrfs_set_super_incompat_flags(disk_super, features);
1779         }
1780         btrfs_end_transaction(trans, root);
1781
1782         return 0;
1783 }
1784
1785 /*
1786  * there are many ways the trans_start and trans_end ioctls can lead
1787  * to deadlocks.  They should only be used by applications that
1788  * basically own the machine, and have a very in depth understanding
1789  * of all the possible deadlocks and enospc problems.
1790  */
1791 long btrfs_ioctl_trans_end(struct file *file)
1792 {
1793         struct inode *inode = fdentry(file)->d_inode;
1794         struct btrfs_root *root = BTRFS_I(inode)->root;
1795         struct btrfs_trans_handle *trans;
1796
1797         trans = file->private_data;
1798         if (!trans)
1799                 return -EINVAL;
1800         file->private_data = NULL;
1801
1802         btrfs_end_transaction(trans, root);
1803
1804         mutex_lock(&root->fs_info->trans_mutex);
1805         root->fs_info->open_ioctl_trans--;
1806         mutex_unlock(&root->fs_info->trans_mutex);
1807
1808         mnt_drop_write(file->f_path.mnt);
1809         return 0;
1810 }
1811
1812 long btrfs_ioctl(struct file *file, unsigned int
1813                 cmd, unsigned long arg)
1814 {
1815         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
1816         void __user *argp = (void __user *)arg;
1817
1818         switch (cmd) {
1819         case FS_IOC_GETFLAGS:
1820                 return btrfs_ioctl_getflags(file, argp);
1821         case FS_IOC_SETFLAGS:
1822                 return btrfs_ioctl_setflags(file, argp);
1823         case FS_IOC_GETVERSION:
1824                 return btrfs_ioctl_getversion(file, argp);
1825         case BTRFS_IOC_SNAP_CREATE:
1826                 return btrfs_ioctl_snap_create(file, argp, 0);
1827         case BTRFS_IOC_SUBVOL_CREATE:
1828                 return btrfs_ioctl_snap_create(file, argp, 1);
1829         case BTRFS_IOC_SNAP_DESTROY:
1830                 return btrfs_ioctl_snap_destroy(file, argp);
1831         case BTRFS_IOC_DEFAULT_SUBVOL:
1832                 return btrfs_ioctl_default_subvol(file, argp);
1833         case BTRFS_IOC_DEFRAG:
1834                 return btrfs_ioctl_defrag(file);
1835         case BTRFS_IOC_RESIZE:
1836                 return btrfs_ioctl_resize(root, argp);
1837         case BTRFS_IOC_ADD_DEV:
1838                 return btrfs_ioctl_add_dev(root, argp);
1839         case BTRFS_IOC_RM_DEV:
1840                 return btrfs_ioctl_rm_dev(root, argp);
1841         case BTRFS_IOC_BALANCE:
1842                 return btrfs_balance(root->fs_info->dev_root);
1843         case BTRFS_IOC_CLONE:
1844                 return btrfs_ioctl_clone(file, arg, 0, 0, 0);
1845         case BTRFS_IOC_CLONE_RANGE:
1846                 return btrfs_ioctl_clone_range(file, argp);
1847         case BTRFS_IOC_TRANS_START:
1848                 return btrfs_ioctl_trans_start(file);
1849         case BTRFS_IOC_TRANS_END:
1850                 return btrfs_ioctl_trans_end(file);
1851         case BTRFS_IOC_TREE_SEARCH:
1852                 return btrfs_ioctl_tree_search(file, argp);
1853         case BTRFS_IOC_INO_LOOKUP:
1854                 return btrfs_ioctl_ino_lookup(file, argp);
1855         case BTRFS_IOC_SYNC:
1856                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
1857                 return 0;
1858         }
1859
1860         return -ENOTTY;
1861 }