fs/btrfs/super.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/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/fs.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/highmem.h>
  25 #include <linux/time.h>
  26 #include <linux/init.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mount.h>
  31 #include <linux/mpage.h>
  32 #include <linux/swap.h>
  33 #include <linux/writeback.h>
  34 #include <linux/statfs.h>
  35 #include <linux/compat.h>
  36 #include <linux/parser.h>
  37 #include <linux/ctype.h>
  38 #include <linux/namei.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/magic.h>
  41 #include "compat.h"
  42 #include "ctree.h"
  43 #include "disk-io.h"
  44 #include "transaction.h"
  45 #include "btrfs_inode.h"
  46 #include "ioctl.h"
  47 #include "print-tree.h"
  48 #include "xattr.h"
  49 #include "volumes.h"
  50 #include "version.h"
  51 #include "export.h"
  52 #include "compression.h"
  53
  54 static const struct super_operations btrfs_super_ops;
  55
  56 static void btrfs_put_super(struct super_block *sb)
  57 {
  58         struct btrfs_root *root = btrfs_sb(sb);
  59         int ret;
  60
  61         ret = close_ctree(root);
  62         sb->s_fs_info = NULL;
  63 }
  64
  65 enum {
  66         Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
  67         Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
  68         Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl,
  69         Opt_compress, Opt_compress_force, Opt_notreelog, Opt_ratio,
  70         Opt_flushoncommit,
  71         Opt_discard, Opt_err,
  72 };
  73
  74 static match_table_t tokens = {
  75         {Opt_degraded, "degraded"},
  76         {Opt_subvol, "subvol=%s"},
  77         {Opt_device, "device=%s"},
  78         {Opt_nodatasum, "nodatasum"},
  79         {Opt_nodatacow, "nodatacow"},
  80         {Opt_nobarrier, "nobarrier"},
  81         {Opt_max_extent, "max_extent=%s"},
  82         {Opt_max_inline, "max_inline=%s"},
  83         {Opt_alloc_start, "alloc_start=%s"},
  84         {Opt_thread_pool, "thread_pool=%d"},
  85         {Opt_compress, "compress"},
  86         {Opt_compress_force, "compress-force"},
  87         {Opt_ssd, "ssd"},
  88         {Opt_ssd_spread, "ssd_spread"},
  89         {Opt_nossd, "nossd"},
  90         {Opt_noacl, "noacl"},
  91         {Opt_notreelog, "notreelog"},
  92         {Opt_flushoncommit, "flushoncommit"},
  93         {Opt_ratio, "metadata_ratio=%d"},
  94         {Opt_discard, "discard"},
  95         {Opt_err, NULL},
  96 };
  97
  98 u64 btrfs_parse_size(char *str)
  99 {
 100         u64 res;
 101         int mult = 1;
 102         char *end;
 103         char last;
 104
 105         res = simple_strtoul(str, &end, 10);
 106
 107         last = end[0];
 108         if (isalpha(last)) {
 109                 last = tolower(last);
 110                 switch (last) {
 111                 case 'g':
 112                         mult *= 1024;
 113                 case 'm':
 114                         mult *= 1024;
 115                 case 'k':
 116                         mult *= 1024;
 117                 }
 118                 res = res * mult;
 119         }
 120         return res;
 121 }
 122
 123 /*
 124  * Regular mount options parser.  Everything that is needed only when
 125  * reading in a new superblock is parsed here.
 126  */
 127 int btrfs_parse_options(struct btrfs_root *root, char *options)
 128 {
 129         struct btrfs_fs_info *info = root->fs_info;
 130         substring_t args[MAX_OPT_ARGS];
 131         char *p, *num, *orig;
 132         int intarg;
 133         int ret = 0;
 134
 135         if (!options)
 136                 return 0;
 137
 138         /*
 139          * strsep changes the string, duplicate it because parse_options
 140          * gets called twice
 141          */
 142         options = kstrdup(options, GFP_NOFS);
 143         if (!options)
 144                 return -ENOMEM;
 145
 146         orig = options;
 147
 148         while ((p = strsep(&options, ",")) != NULL) {
 149                 int token;
 150                 if (!*p)
 151                         continue;
 152
 153                 token = match_token(p, tokens, args);
 154                 switch (token) {
 155                 case Opt_degraded:
 156                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 157                         btrfs_set_opt(info->mount_opt, DEGRADED);
 158                         break;
 159                 case Opt_subvol:
 160                 case Opt_device:
 161                         /*
 162                          * These are parsed by btrfs_parse_early_options
 163                          * and can be happily ignored here.
 164                          */
 165                         break;
 166                 case Opt_nodatasum:
 167                         printk(KERN_INFO "btrfs: setting nodatasum\n");
 168                         btrfs_set_opt(info->mount_opt, NODATASUM);
 169                         break;
 170                 case Opt_nodatacow:
 171                         printk(KERN_INFO "btrfs: setting nodatacow\n");
 172                         btrfs_set_opt(info->mount_opt, NODATACOW);
 173                         btrfs_set_opt(info->mount_opt, NODATASUM);
 174                         break;
 175                 case Opt_compress:
 176                         printk(KERN_INFO "btrfs: use compression\n");
 177                         btrfs_set_opt(info->mount_opt, COMPRESS);
 178                         break;
 179                 case Opt_compress_force:
 180                         printk(KERN_INFO "btrfs: forcing compression\n");
 181                         btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 182                         btrfs_set_opt(info->mount_opt, COMPRESS);
 183                         break;
 184                 case Opt_ssd:
 185                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 186                         btrfs_set_opt(info->mount_opt, SSD);
 187                         break;
 188                 case Opt_ssd_spread:
 189                         printk(KERN_INFO "btrfs: use spread ssd "
 190                                "allocation scheme\n");
 191                         btrfs_set_opt(info->mount_opt, SSD);
 192                         btrfs_set_opt(info->mount_opt, SSD_SPREAD);
 193                         break;
 194                 case Opt_nossd:
 195                         printk(KERN_INFO "btrfs: not using ssd allocation "
 196                                "scheme\n");
 197                         btrfs_set_opt(info->mount_opt, NOSSD);
 198                         btrfs_clear_opt(info->mount_opt, SSD);
 199                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
 200                         break;
 201                 case Opt_nobarrier:
 202                         printk(KERN_INFO "btrfs: turning off barriers\n");
 203                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 204                         break;
 205                 case Opt_thread_pool:
 206                         intarg = 0;
 207                         match_int(&args[0], &intarg);
 208                         if (intarg) {
 209                                 info->thread_pool_size = intarg;
 210                                 printk(KERN_INFO "btrfs: thread pool %d\n",
 211                                        info->thread_pool_size);
 212                         }
 213                         break;
 214                 case Opt_max_extent:
 215                         num = match_strdup(&args[0]);
 216                         if (num) {
 217                                 info->max_extent = btrfs_parse_size(num);
 218                                 kfree(num);
 219
 220                                 info->max_extent = max_t(u64,
 221                                         info->max_extent, root->sectorsize);
 222                                 printk(KERN_INFO "btrfs: max_extent at %llu\n",
 223                                        (unsigned long long)info->max_extent);
 224                         }
 225                         break;
 226                 case Opt_max_inline:
 227                         num = match_strdup(&args[0]);
 228                         if (num) {
 229                                 info->max_inline = btrfs_parse_size(num);
 230                                 kfree(num);
 231
 232                                 if (info->max_inline) {
 233                                         info->max_inline = max_t(u64,
 234                                                 info->max_inline,
 235                                                 root->sectorsize);
 236                                 }
 237                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 238                                         (unsigned long long)info->max_inline);
 239                         }
 240                         break;
 241                 case Opt_alloc_start:
 242                         num = match_strdup(&args[0]);
 243                         if (num) {
 244                                 info->alloc_start = btrfs_parse_size(num);
 245                                 kfree(num);
 246                                 printk(KERN_INFO
 247                                         "btrfs: allocations start at %llu\n",
 248                                         (unsigned long long)info->alloc_start);
 249                         }
 250                         break;
 251                 case Opt_noacl:
 252                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 253                         break;
 254                 case Opt_notreelog:
 255                         printk(KERN_INFO "btrfs: disabling tree log\n");
 256                         btrfs_set_opt(info->mount_opt, NOTREELOG);
 257                         break;
 258                 case Opt_flushoncommit:
 259                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
 260                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
 261                         break;
 262                 case Opt_ratio:
 263                         intarg = 0;
 264                         match_int(&args[0], &intarg);
 265                         if (intarg) {
 266                                 info->metadata_ratio = intarg;
 267                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
 268                                        info->metadata_ratio);
 269                         }
 270                         break;
 271                 case Opt_discard:
 272                         btrfs_set_opt(info->mount_opt, DISCARD);
 273                         break;
 274                 case Opt_err:
 275                         printk(KERN_INFO "btrfs: unrecognized mount option "
 276                                "'%s'\n", p);
 277                         ret = -EINVAL;
 278                         goto out;
 279                 default:
 280                         break;
 281                 }
 282         }
 283 out:
 284         kfree(orig);
 285         return ret;
 286 }
 287
 288 /*
 289  * Parse mount options that are required early in the mount process.
 290  *
 291  * All other options will be parsed on much later in the mount process and
 292  * only when we need to allocate a new super block.
 293  */
 294 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 295                 void *holder, char **subvol_name,
 296                 struct btrfs_fs_devices **fs_devices)
 297 {
 298         substring_t args[MAX_OPT_ARGS];
 299         char *opts, *p;
 300         int error = 0;
 301
 302         if (!options)
 303                 goto out;
 304
 305         /*
 306          * strsep changes the string, duplicate it because parse_options
 307          * gets called twice
 308          */
 309         opts = kstrdup(options, GFP_KERNEL);
 310         if (!opts)
 311                 return -ENOMEM;
 312
 313         while ((p = strsep(&opts, ",")) != NULL) {
 314                 int token;
 315                 if (!*p)
 316                         continue;
 317
 318                 token = match_token(p, tokens, args);
 319                 switch (token) {
 320                 case Opt_subvol:
 321                         *subvol_name = match_strdup(&args[0]);
 322                         break;
 323                 case Opt_device:
 324                         error = btrfs_scan_one_device(match_strdup(&args[0]),
 325                                         flags, holder, fs_devices);
 326                         if (error)
 327                                 goto out_free_opts;
 328                         break;
 329                 default:
 330                         break;
 331                 }
 332         }
 333
 334  out_free_opts:
 335         kfree(opts);
 336  out:
 337         /*
 338          * If no subvolume name is specified we use the default one.  Allocate
 339          * a copy of the string "." here so that code later in the
 340          * mount path doesn't care if it's the default volume or another one.
 341          */
 342         if (!*subvol_name) {
 343                 *subvol_name = kstrdup(".", GFP_KERNEL);
 344                 if (!*subvol_name)
 345                         return -ENOMEM;
 346         }
 347         return error;
 348 }
 349
 350 static int btrfs_fill_super(struct super_block *sb,
 351                             struct btrfs_fs_devices *fs_devices,
 352                             void *data, int silent)
 353 {
 354         struct inode *inode;
 355         struct dentry *root_dentry;
 356         struct btrfs_super_block *disk_super;
 357         struct btrfs_root *tree_root;
 358         struct btrfs_key key;
 359         int err;
 360
 361         sb->s_maxbytes = MAX_LFS_FILESIZE;
 362         sb->s_magic = BTRFS_SUPER_MAGIC;
 363         sb->s_op = &btrfs_super_ops;
 364         sb->s_export_op = &btrfs_export_ops;
 365         sb->s_xattr = btrfs_xattr_handlers;
 366         sb->s_time_gran = 1;
 367 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 368         sb->s_flags |= MS_POSIXACL;
 369 #endif
 370
 371         tree_root = open_ctree(sb, fs_devices, (char *)data);
 372
 373         if (IS_ERR(tree_root)) {
 374                 printk("btrfs: open_ctree failed\n");
 375                 return PTR_ERR(tree_root);
 376         }
 377         sb->s_fs_info = tree_root;
 378         disk_super = &tree_root->fs_info->super_copy;
 379
 380         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 381         key.type = BTRFS_INODE_ITEM_KEY;
 382         key.offset = 0;
 383         inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root);
 384         if (IS_ERR(inode)) {
 385                 err = PTR_ERR(inode);
 386                 goto fail_close;
 387         }
 388
 389         root_dentry = d_alloc_root(inode);
 390         if (!root_dentry) {
 391                 iput(inode);
 392                 err = -ENOMEM;
 393                 goto fail_close;
 394         }
 395 #if 0
 396         /* this does the super kobj at the same time */
 397         err = btrfs_sysfs_add_super(tree_root->fs_info);
 398         if (err)
 399                 goto fail_close;
 400 #endif
 401
 402         sb->s_root = root_dentry;
 403
 404         save_mount_options(sb, data);
 405         return 0;
 406
 407 fail_close:
 408         close_ctree(tree_root);
 409         return err;
 410 }
 411
 412 int btrfs_sync_fs(struct super_block *sb, int wait)
 413 {
 414         struct btrfs_trans_handle *trans;
 415         struct btrfs_root *root = btrfs_sb(sb);
 416         int ret;
 417
 418         if (!wait) {
 419                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 420                 return 0;
 421         }
 422
 423         btrfs_start_delalloc_inodes(root, 0);
 424         btrfs_wait_ordered_extents(root, 0, 0);
 425
 426         trans = btrfs_start_transaction(root, 1);
 427         ret = btrfs_commit_transaction(trans, root);
 428         return ret;
 429 }
 430
 431 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 432 {
 433         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
 434         struct btrfs_fs_info *info = root->fs_info;
 435
 436         if (btrfs_test_opt(root, DEGRADED))
 437                 seq_puts(seq, ",degraded");
 438         if (btrfs_test_opt(root, NODATASUM))
 439                 seq_puts(seq, ",nodatasum");
 440         if (btrfs_test_opt(root, NODATACOW))
 441                 seq_puts(seq, ",nodatacow");
 442         if (btrfs_test_opt(root, NOBARRIER))
 443                 seq_puts(seq, ",nobarrier");
 444         if (info->max_extent != (u64)-1)
 445                 seq_printf(seq, ",max_extent=%llu",
 446                            (unsigned long long)info->max_extent);
 447         if (info->max_inline != 8192 * 1024)
 448                 seq_printf(seq, ",max_inline=%llu",
 449                            (unsigned long long)info->max_inline);
 450         if (info->alloc_start != 0)
 451                 seq_printf(seq, ",alloc_start=%llu",
 452                            (unsigned long long)info->alloc_start);
 453         if (info->thread_pool_size !=  min_t(unsigned long,
 454                                              num_online_cpus() + 2, 8))
 455                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 456         if (btrfs_test_opt(root, COMPRESS))
 457                 seq_puts(seq, ",compress");
 458         if (btrfs_test_opt(root, NOSSD))
 459                 seq_puts(seq, ",nossd");
 460         if (btrfs_test_opt(root, SSD_SPREAD))
 461                 seq_puts(seq, ",ssd_spread");
 462         else if (btrfs_test_opt(root, SSD))
 463                 seq_puts(seq, ",ssd");
 464         if (btrfs_test_opt(root, NOTREELOG))
 465                 seq_puts(seq, ",notreelog");
 466         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 467                 seq_puts(seq, ",flushoncommit");
 468         if (btrfs_test_opt(root, DISCARD))
 469                 seq_puts(seq, ",discard");
 470         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 471                 seq_puts(seq, ",noacl");
 472         return 0;
 473 }
 474
 475 static int btrfs_test_super(struct super_block *s, void *data)
 476 {
 477         struct btrfs_fs_devices *test_fs_devices = data;
 478         struct btrfs_root *root = btrfs_sb(s);
 479
 480         return root->fs_info->fs_devices == test_fs_devices;
 481 }
 482
 483 /*
 484  * Find a superblock for the given device / mount point.
 485  *
 486  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 487  *        for multiple device setup.  Make sure to keep it in sync.
 488  */
 489 static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 490                 const char *dev_name, void *data, struct vfsmount *mnt)
 491 {
 492         char *subvol_name = NULL;
 493         struct block_device *bdev = NULL;
 494         struct super_block *s;
 495         struct dentry *root;
 496         struct btrfs_fs_devices *fs_devices = NULL;
 497         fmode_t mode = FMODE_READ;
 498         int error = 0;
 499
 500         if (!(flags & MS_RDONLY))
 501                 mode |= FMODE_WRITE;
 502
 503         error = btrfs_parse_early_options(data, mode, fs_type,
 504                                           &subvol_name, &fs_devices);
 505         if (error)
 506                 return error;
 507
 508         error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
 509         if (error)
 510                 goto error_free_subvol_name;
 511
 512         error = btrfs_open_devices(fs_devices, mode, fs_type);
 513         if (error)
 514                 goto error_free_subvol_name;
 515
 516         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 517                 error = -EACCES;
 518                 goto error_close_devices;
 519         }
 520
 521         bdev = fs_devices->latest_bdev;
 522         s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
 523         if (IS_ERR(s))
 524                 goto error_s;
 525
 526         if (s->s_root) {
 527                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 528                         deactivate_locked_super(s);
 529                         error = -EBUSY;
 530                         goto error_close_devices;
 531                 }
 532
 533                 btrfs_close_devices(fs_devices);
 534         } else {
 535                 char b[BDEVNAME_SIZE];
 536
 537                 s->s_flags = flags;
 538                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 539                 error = btrfs_fill_super(s, fs_devices, data,
 540                                          flags & MS_SILENT ? 1 : 0);
 541                 if (error) {
 542                         deactivate_locked_super(s);
 543                         goto error_free_subvol_name;
 544                 }
 545
 546                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 547                 s->s_flags |= MS_ACTIVE;
 548         }
 549
 550         if (!strcmp(subvol_name, "."))
 551                 root = dget(s->s_root);
 552         else {
 553                 mutex_lock(&s->s_root->d_inode->i_mutex);
 554                 root = lookup_one_len(subvol_name, s->s_root,
 555                                       strlen(subvol_name));
 556                 mutex_unlock(&s->s_root->d_inode->i_mutex);
 557
 558                 if (IS_ERR(root)) {
 559                         deactivate_locked_super(s);
 560                         error = PTR_ERR(root);
 561                         goto error_free_subvol_name;
 562                 }
 563                 if (!root->d_inode) {
 564                         dput(root);
 565                         deactivate_locked_super(s);
 566                         error = -ENXIO;
 567                         goto error_free_subvol_name;
 568                 }
 569         }
 570
 571         mnt->mnt_sb = s;
 572         mnt->mnt_root = root;
 573
 574         kfree(subvol_name);
 575         return 0;
 576
 577 error_s:
 578         error = PTR_ERR(s);
 579 error_close_devices:
 580         btrfs_close_devices(fs_devices);
 581 error_free_subvol_name:
 582         kfree(subvol_name);
 583         return error;
 584 }
 585
 586 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 587 {
 588         struct btrfs_root *root = btrfs_sb(sb);
 589         int ret;
 590
 591         ret = btrfs_parse_options(root, data);
 592         if (ret)
 593                 return -EINVAL;
 594
 595         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 596                 return 0;
 597
 598         if (*flags & MS_RDONLY) {
 599                 sb->s_flags |= MS_RDONLY;
 600
 601                 ret =  btrfs_commit_super(root);
 602                 WARN_ON(ret);
 603         } else {
 604                 if (root->fs_info->fs_devices->rw_devices == 0)
 605                         return -EACCES;
 606
 607                 if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
 608                         return -EINVAL;
 609
 610                 /* recover relocation */
 611                 ret = btrfs_recover_relocation(root);
 612                 WARN_ON(ret);
 613
 614                 ret = btrfs_cleanup_fs_roots(root->fs_info);
 615                 WARN_ON(ret);
 616
 617                 sb->s_flags &= ~MS_RDONLY;
 618         }
 619
 620         return 0;
 621 }
 622
 623 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 624 {
 625         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
 626         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
 627         int bits = dentry->d_sb->s_blocksize_bits;
 628         __be32 *fsid = (__be32 *)root->fs_info->fsid;
 629
 630         buf->f_namelen = BTRFS_NAME_LEN;
 631         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
 632         buf->f_bfree = buf->f_blocks -
 633                 (btrfs_super_bytes_used(disk_super) >> bits);
 634         buf->f_bavail = buf->f_bfree;
 635         buf->f_bsize = dentry->d_sb->s_blocksize;
 636         buf->f_type = BTRFS_SUPER_MAGIC;
 637
 638         /* We treat it as constant endianness (it doesn't matter _which_)
 639            because we want the fsid to come out the same whether mounted
 640            on a big-endian or little-endian host */
 641         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
 642         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
 643         /* Mask in the root object ID too, to disambiguate subvols */
 644         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
 645         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
 646
 647         return 0;
 648 }
 649
 650 static struct file_system_type btrfs_fs_type = {
 651         .owner          = THIS_MODULE,
 652         .name           = "btrfs",
 653         .get_sb         = btrfs_get_sb,
 654         .kill_sb        = kill_anon_super,
 655         .fs_flags       = FS_REQUIRES_DEV,
 656 };
 657
 658 /*
 659  * used by btrfsctl to scan devices when no FS is mounted
 660  */
 661 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 662                                 unsigned long arg)
 663 {
 664         struct btrfs_ioctl_vol_args *vol;
 665         struct btrfs_fs_devices *fs_devices;
 666         int ret = -ENOTTY;
 667
 668         if (!capable(CAP_SYS_ADMIN))
 669                 return -EPERM;
 670
 671         vol = memdup_user((void __user *)arg, sizeof(*vol));
 672         if (IS_ERR(vol))
 673                 return PTR_ERR(vol);
 674
 675         switch (cmd) {
 676         case BTRFS_IOC_SCAN_DEV:
 677                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
 678                                             &btrfs_fs_type, &fs_devices);
 679                 break;
 680         }
 681
 682         kfree(vol);
 683         return ret;
 684 }
 685
 686 static int btrfs_freeze(struct super_block *sb)
 687 {
 688         struct btrfs_root *root = btrfs_sb(sb);
 689         mutex_lock(&root->fs_info->transaction_kthread_mutex);
 690         mutex_lock(&root->fs_info->cleaner_mutex);
 691         return 0;
 692 }
 693
 694 static int btrfs_unfreeze(struct super_block *sb)
 695 {
 696         struct btrfs_root *root = btrfs_sb(sb);
 697         mutex_unlock(&root->fs_info->cleaner_mutex);
 698         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
 699         return 0;
 700 }
 701
 702 static const struct super_operations btrfs_super_ops = {
 703         .drop_inode     = btrfs_drop_inode,
 704         .delete_inode   = btrfs_delete_inode,
 705         .put_super      = btrfs_put_super,
 706         .sync_fs        = btrfs_sync_fs,
 707         .show_options   = btrfs_show_options,
 708         .write_inode    = btrfs_write_inode,
 709         .dirty_inode    = btrfs_dirty_inode,
 710         .alloc_inode    = btrfs_alloc_inode,
 711         .destroy_inode  = btrfs_destroy_inode,
 712         .statfs         = btrfs_statfs,
 713         .remount_fs     = btrfs_remount,
 714         .freeze_fs      = btrfs_freeze,
 715         .unfreeze_fs    = btrfs_unfreeze,
 716 };
 717
 718 static const struct file_operations btrfs_ctl_fops = {
 719         .unlocked_ioctl  = btrfs_control_ioctl,
 720         .compat_ioctl = btrfs_control_ioctl,
 721         .owner   = THIS_MODULE,
 722 };
 723
 724 static struct miscdevice btrfs_misc = {
 725         .minor          = MISC_DYNAMIC_MINOR,
 726         .name           = "btrfs-control",
 727         .fops           = &btrfs_ctl_fops
 728 };
 729
 730 static int btrfs_interface_init(void)
 731 {
 732         return misc_register(&btrfs_misc);
 733 }
 734
 735 static void btrfs_interface_exit(void)
 736 {
 737         if (misc_deregister(&btrfs_misc) < 0)
 738                 printk(KERN_INFO "misc_deregister failed for control device");
 739 }
 740
 741 static int __init init_btrfs_fs(void)
 742 {
 743         int err;
 744
 745         err = btrfs_init_sysfs();
 746         if (err)
 747                 return err;
 748
 749         err = btrfs_init_cachep();
 750         if (err)
 751                 goto free_sysfs;
 752
 753         err = extent_io_init();
 754         if (err)
 755                 goto free_cachep;
 756
 757         err = extent_map_init();
 758         if (err)
 759                 goto free_extent_io;
 760
 761         err = btrfs_interface_init();
 762         if (err)
 763                 goto free_extent_map;
 764
 765         err = register_filesystem(&btrfs_fs_type);
 766         if (err)
 767                 goto unregister_ioctl;
 768
 769         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
 770         return 0;
 771
 772 unregister_ioctl:
 773         btrfs_interface_exit();
 774 free_extent_map:
 775         extent_map_exit();
 776 free_extent_io:
 777         extent_io_exit();
 778 free_cachep:
 779         btrfs_destroy_cachep();
 780 free_sysfs:
 781         btrfs_exit_sysfs();
 782         return err;
 783 }
 784
 785 static void __exit exit_btrfs_fs(void)
 786 {
 787         btrfs_destroy_cachep();
 788         extent_map_exit();
 789         extent_io_exit();
 790         btrfs_interface_exit();
 791         unregister_filesystem(&btrfs_fs_type);
 792         btrfs_exit_sysfs();
 793         btrfs_cleanup_fs_uuids();
 794         btrfs_zlib_exit();
 795 }
 796
 797 module_init(init_btrfs_fs)
 798 module_exit(exit_btrfs_fs)
 799
 800 MODULE_LICENSE("GPL");