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 <linux/slab.h>
  42 #include <linux/cleancache.h>
  43 #include <linux/ratelimit.h>
  44 #include <linux/btrfs.h>
  45 #include "delayed-inode.h"
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "xattr.h"
  52 #include "volumes.h"
  53 #include "export.h"
  54 #include "compression.h"
  55 #include "rcu-string.h"
  56 #include "dev-replace.h"
  57 #include "free-space-cache.h"
  58 #include "backref.h"
  59 #include "tests/btrfs-tests.h"
  60
  61 #define CREATE_TRACE_POINTS
  62 #include <trace/events/btrfs.h>
  63
  64 static const struct super_operations btrfs_super_ops;
  65 static struct file_system_type btrfs_fs_type;
  66
  67 static const char *btrfs_decode_error(int errno)
  68 {
  69         char *errstr = "unknown";
  70
  71         switch (errno) {
  72         case -EIO:
  73                 errstr = "IO failure";
  74                 break;
  75         case -ENOMEM:
  76                 errstr = "Out of memory";
  77                 break;
  78         case -EROFS:
  79                 errstr = "Readonly filesystem";
  80                 break;
  81         case -EEXIST:
  82                 errstr = "Object already exists";
  83                 break;
  84         case -ENOSPC:
  85                 errstr = "No space left";
  86                 break;
  87         case -ENOENT:
  88                 errstr = "No such entry";
  89                 break;
  90         }
  91
  92         return errstr;
  93 }
  94
  95 static void save_error_info(struct btrfs_fs_info *fs_info)
  96 {
  97         /*
  98          * today we only save the error info into ram.  Long term we'll
  99          * also send it down to the disk
 100          */
 101         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 102 }
 103
 104 /* btrfs handle error by forcing the filesystem readonly */
 105 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 106 {
 107         struct super_block *sb = fs_info->sb;
 108
 109         if (sb->s_flags & MS_RDONLY)
 110                 return;
 111
 112         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 113                 sb->s_flags |= MS_RDONLY;
 114                 btrfs_info(fs_info, "forced readonly");
 115                 /*
 116                  * Note that a running device replace operation is not
 117                  * canceled here although there is no way to update
 118                  * the progress. It would add the risk of a deadlock,
 119                  * therefore the canceling is ommited. The only penalty
 120                  * is that some I/O remains active until the procedure
 121                  * completes. The next time when the filesystem is
 122                  * mounted writeable again, the device replace
 123                  * operation continues.
 124                  */
 125         }
 126 }
 127
 128 #ifdef CONFIG_PRINTK
 129 /*
 130  * __btrfs_std_error decodes expected errors from the caller and
 131  * invokes the approciate error response.
 132  */
 133 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 134                        unsigned int line, int errno, const char *fmt, ...)
 135 {
 136         struct super_block *sb = fs_info->sb;
 137         const char *errstr;
 138
 139         /*
 140          * Special case: if the error is EROFS, and we're already
 141          * under MS_RDONLY, then it is safe here.
 142          */
 143         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 144                 return;
 145
 146         errstr = btrfs_decode_error(errno);
 147         if (fmt) {
 148                 struct va_format vaf;
 149                 va_list args;
 150
 151                 va_start(args, fmt);
 152                 vaf.fmt = fmt;
 153                 vaf.va = &args;
 154
 155                 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 156                         sb->s_id, function, line, errno, errstr, &vaf);
 157                 va_end(args);
 158         } else {
 159                 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: errno=%d %s\n",
 160                         sb->s_id, function, line, errno, errstr);
 161         }
 162
 163         /* Don't go through full error handling during mount */
 164         save_error_info(fs_info);
 165         if (sb->s_flags & MS_BORN)
 166                 btrfs_handle_error(fs_info);
 167 }
 168
 169 static const char * const logtypes[] = {
 170         "emergency",
 171         "alert",
 172         "critical",
 173         "error",
 174         "warning",
 175         "notice",
 176         "info",
 177         "debug",
 178 };
 179
 180 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 181 {
 182         struct super_block *sb = fs_info->sb;
 183         char lvl[4];
 184         struct va_format vaf;
 185         va_list args;
 186         const char *type = logtypes[4];
 187         int kern_level;
 188
 189         va_start(args, fmt);
 190
 191         kern_level = printk_get_level(fmt);
 192         if (kern_level) {
 193                 size_t size = printk_skip_level(fmt) - fmt;
 194                 memcpy(lvl, fmt,  size);
 195                 lvl[size] = '\0';
 196                 fmt += size;
 197                 type = logtypes[kern_level - '0'];
 198         } else
 199                 *lvl = '\0';
 200
 201         vaf.fmt = fmt;
 202         vaf.va = &args;
 203
 204         printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
 205
 206         va_end(args);
 207 }
 208
 209 #else
 210
 211 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 212                        unsigned int line, int errno, const char *fmt, ...)
 213 {
 214         struct super_block *sb = fs_info->sb;
 215
 216         /*
 217          * Special case: if the error is EROFS, and we're already
 218          * under MS_RDONLY, then it is safe here.
 219          */
 220         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 221                 return;
 222
 223         /* Don't go through full error handling during mount */
 224         if (sb->s_flags & MS_BORN) {
 225                 save_error_info(fs_info);
 226                 btrfs_handle_error(fs_info);
 227         }
 228 }
 229 #endif
 230
 231 /*
 232  * We only mark the transaction aborted and then set the file system read-only.
 233  * This will prevent new transactions from starting or trying to join this
 234  * one.
 235  *
 236  * This means that error recovery at the call site is limited to freeing
 237  * any local memory allocations and passing the error code up without
 238  * further cleanup. The transaction should complete as it normally would
 239  * in the call path but will return -EIO.
 240  *
 241  * We'll complete the cleanup in btrfs_end_transaction and
 242  * btrfs_commit_transaction.
 243  */
 244 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 245                                struct btrfs_root *root, const char *function,
 246                                unsigned int line, int errno)
 247 {
 248         /*
 249          * Report first abort since mount
 250          */
 251         if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,
 252                                 &root->fs_info->fs_state)) {
 253                 WARN(1, KERN_DEBUG "btrfs: Transaction aborted (error %d)\n",
 254                                 errno);
 255         }
 256         trans->aborted = errno;
 257         /* Nothing used. The other threads that have joined this
 258          * transaction may be able to continue. */
 259         if (!trans->blocks_used) {
 260                 const char *errstr;
 261
 262                 errstr = btrfs_decode_error(errno);
 263                 btrfs_warn(root->fs_info,
 264                            "%s:%d: Aborting unused transaction(%s).",
 265                            function, line, errstr);
 266                 return;
 267         }
 268         ACCESS_ONCE(trans->transaction->aborted) = errno;
 269         /* Wake up anybody who may be waiting on this transaction */
 270         wake_up(&root->fs_info->transaction_wait);
 271         wake_up(&root->fs_info->transaction_blocked_wait);
 272         __btrfs_std_error(root->fs_info, function, line, errno, NULL);
 273 }
 274 /*
 275  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 276  * issues an alert, and either panics or BUGs, depending on mount options.
 277  */
 278 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 279                    unsigned int line, int errno, const char *fmt, ...)
 280 {
 281         char *s_id = "<unknown>";
 282         const char *errstr;
 283         struct va_format vaf = { .fmt = fmt };
 284         va_list args;
 285
 286         if (fs_info)
 287                 s_id = fs_info->sb->s_id;
 288
 289         va_start(args, fmt);
 290         vaf.va = &args;
 291
 292         errstr = btrfs_decode_error(errno);
 293         if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
 294                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 295                         s_id, function, line, &vaf, errno, errstr);
 296
 297         printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 298                s_id, function, line, &vaf, errno, errstr);
 299         va_end(args);
 300         /* Caller calls BUG() */
 301 }
 302
 303 static void btrfs_put_super(struct super_block *sb)
 304 {
 305         (void)close_ctree(btrfs_sb(sb)->tree_root);
 306         /* FIXME: need to fix VFS to return error? */
 307         /* AV: return it _where_?  ->put_super() can be triggered by any number
 308          * of async events, up to and including delivery of SIGKILL to the
 309          * last process that kept it busy.  Or segfault in the aforementioned
 310          * process...  Whom would you report that to?
 311          */
 312 }
 313
 314 enum {
 315         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 316         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 317         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 318         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 319         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 320         Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
 321         Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
 322         Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
 323         Opt_check_integrity, Opt_check_integrity_including_extent_data,
 324         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 325         Opt_commit_interval,
 326         Opt_err,
 327 };
 328
 329 static match_table_t tokens = {
 330         {Opt_degraded, "degraded"},
 331         {Opt_subvol, "subvol=%s"},
 332         {Opt_subvolid, "subvolid=%s"},
 333         {Opt_device, "device=%s"},
 334         {Opt_nodatasum, "nodatasum"},
 335         {Opt_nodatacow, "nodatacow"},
 336         {Opt_nobarrier, "nobarrier"},
 337         {Opt_max_inline, "max_inline=%s"},
 338         {Opt_alloc_start, "alloc_start=%s"},
 339         {Opt_thread_pool, "thread_pool=%d"},
 340         {Opt_compress, "compress"},
 341         {Opt_compress_type, "compress=%s"},
 342         {Opt_compress_force, "compress-force"},
 343         {Opt_compress_force_type, "compress-force=%s"},
 344         {Opt_ssd, "ssd"},
 345         {Opt_ssd_spread, "ssd_spread"},
 346         {Opt_nossd, "nossd"},
 347         {Opt_noacl, "noacl"},
 348         {Opt_notreelog, "notreelog"},
 349         {Opt_flushoncommit, "flushoncommit"},
 350         {Opt_ratio, "metadata_ratio=%d"},
 351         {Opt_discard, "discard"},
 352         {Opt_space_cache, "space_cache"},
 353         {Opt_clear_cache, "clear_cache"},
 354         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 355         {Opt_enospc_debug, "enospc_debug"},
 356         {Opt_subvolrootid, "subvolrootid=%d"},
 357         {Opt_defrag, "autodefrag"},
 358         {Opt_inode_cache, "inode_cache"},
 359         {Opt_no_space_cache, "nospace_cache"},
 360         {Opt_recovery, "recovery"},
 361         {Opt_skip_balance, "skip_balance"},
 362         {Opt_check_integrity, "check_int"},
 363         {Opt_check_integrity_including_extent_data, "check_int_data"},
 364         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 365         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 366         {Opt_fatal_errors, "fatal_errors=%s"},
 367         {Opt_commit_interval, "commit=%d"},
 368         {Opt_err, NULL},
 369 };
 370
 371 /*
 372  * Regular mount options parser.  Everything that is needed only when
 373  * reading in a new superblock is parsed here.
 374  * XXX JDM: This needs to be cleaned up for remount.
 375  */
 376 int btrfs_parse_options(struct btrfs_root *root, char *options)
 377 {
 378         struct btrfs_fs_info *info = root->fs_info;
 379         substring_t args[MAX_OPT_ARGS];
 380         char *p, *num, *orig = NULL;
 381         u64 cache_gen;
 382         int intarg;
 383         int ret = 0;
 384         char *compress_type;
 385         bool compress_force = false;
 386
 387         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 388         if (cache_gen)
 389                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 390
 391         if (!options)
 392                 goto out;
 393
 394         /*
 395          * strsep changes the string, duplicate it because parse_options
 396          * gets called twice
 397          */
 398         options = kstrdup(options, GFP_NOFS);
 399         if (!options)
 400                 return -ENOMEM;
 401
 402         orig = options;
 403
 404         while ((p = strsep(&options, ",")) != NULL) {
 405                 int token;
 406                 if (!*p)
 407                         continue;
 408
 409                 token = match_token(p, tokens, args);
 410                 switch (token) {
 411                 case Opt_degraded:
 412                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 413                         btrfs_set_opt(info->mount_opt, DEGRADED);
 414                         break;
 415                 case Opt_subvol:
 416                 case Opt_subvolid:
 417                 case Opt_subvolrootid:
 418                 case Opt_device:
 419                         /*
 420                          * These are parsed by btrfs_parse_early_options
 421                          * and can be happily ignored here.
 422                          */
 423                         break;
 424                 case Opt_nodatasum:
 425                         printk(KERN_INFO "btrfs: setting nodatasum\n");
 426                         btrfs_set_opt(info->mount_opt, NODATASUM);
 427                         break;
 428                 case Opt_nodatacow:
 429                         if (!btrfs_test_opt(root, COMPRESS) ||
 430                                 !btrfs_test_opt(root, FORCE_COMPRESS)) {
 431                                         printk(KERN_INFO "btrfs: setting nodatacow, compression disabled\n");
 432                         } else {
 433                                 printk(KERN_INFO "btrfs: setting nodatacow\n");
 434                         }
 435                         info->compress_type = BTRFS_COMPRESS_NONE;
 436                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 437                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 438                         btrfs_set_opt(info->mount_opt, NODATACOW);
 439                         btrfs_set_opt(info->mount_opt, NODATASUM);
 440                         break;
 441                 case Opt_compress_force:
 442                 case Opt_compress_force_type:
 443                         compress_force = true;
 444                         /* Fallthrough */
 445                 case Opt_compress:
 446                 case Opt_compress_type:
 447                         if (token == Opt_compress ||
 448                             token == Opt_compress_force ||
 449                             strcmp(args[0].from, "zlib") == 0) {
 450                                 compress_type = "zlib";
 451                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 452                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 453                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 454                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 455                         } else if (strcmp(args[0].from, "lzo") == 0) {
 456                                 compress_type = "lzo";
 457                                 info->compress_type = BTRFS_COMPRESS_LZO;
 458                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 459                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 460                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 461                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 462                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 463                                 compress_type = "no";
 464                                 info->compress_type = BTRFS_COMPRESS_NONE;
 465                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 466                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 467                                 compress_force = false;
 468                         } else {
 469                                 ret = -EINVAL;
 470                                 goto out;
 471                         }
 472
 473                         if (compress_force) {
 474                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 475                                 pr_info("btrfs: force %s compression\n",
 476                                         compress_type);
 477                         } else
 478                                 pr_info("btrfs: use %s compression\n",
 479                                         compress_type);
 480                         break;
 481                 case Opt_ssd:
 482                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 483                         btrfs_set_opt(info->mount_opt, SSD);
 484                         break;
 485                 case Opt_ssd_spread:
 486                         printk(KERN_INFO "btrfs: use spread ssd "
 487                                "allocation scheme\n");
 488                         btrfs_set_opt(info->mount_opt, SSD);
 489                         btrfs_set_opt(info->mount_opt, SSD_SPREAD);
 490                         break;
 491                 case Opt_nossd:
 492                         printk(KERN_INFO "btrfs: not using ssd allocation "
 493                                "scheme\n");
 494                         btrfs_set_opt(info->mount_opt, NOSSD);
 495                         btrfs_clear_opt(info->mount_opt, SSD);
 496                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
 497                         break;
 498                 case Opt_nobarrier:
 499                         printk(KERN_INFO "btrfs: turning off barriers\n");
 500                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 501                         break;
 502                 case Opt_thread_pool:
 503                         ret = match_int(&args[0], &intarg);
 504                         if (ret) {
 505                                 goto out;
 506                         } else if (intarg > 0) {
 507                                 info->thread_pool_size = intarg;
 508                         } else {
 509                                 ret = -EINVAL;
 510                                 goto out;
 511                         }
 512                         break;
 513                 case Opt_max_inline:
 514                         num = match_strdup(&args[0]);
 515                         if (num) {
 516                                 info->max_inline = memparse(num, NULL);
 517                                 kfree(num);
 518
 519                                 if (info->max_inline) {
 520                                         info->max_inline = max_t(u64,
 521                                                 info->max_inline,
 522                                                 root->sectorsize);
 523                                 }
 524                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 525                                         info->max_inline);
 526                         } else {
 527                                 ret = -ENOMEM;
 528                                 goto out;
 529                         }
 530                         break;
 531                 case Opt_alloc_start:
 532                         num = match_strdup(&args[0]);
 533                         if (num) {
 534                                 mutex_lock(&info->chunk_mutex);
 535                                 info->alloc_start = memparse(num, NULL);
 536                                 mutex_unlock(&info->chunk_mutex);
 537                                 kfree(num);
 538                                 printk(KERN_INFO
 539                                         "btrfs: allocations start at %llu\n",
 540                                         info->alloc_start);
 541                         } else {
 542                                 ret = -ENOMEM;
 543                                 goto out;
 544                         }
 545                         break;
 546                 case Opt_noacl:
 547                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 548                         break;
 549                 case Opt_notreelog:
 550                         printk(KERN_INFO "btrfs: disabling tree log\n");
 551                         btrfs_set_opt(info->mount_opt, NOTREELOG);
 552                         break;
 553                 case Opt_flushoncommit:
 554                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
 555                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
 556                         break;
 557                 case Opt_ratio:
 558                         ret = match_int(&args[0], &intarg);
 559                         if (ret) {
 560                                 goto out;
 561                         } else if (intarg >= 0) {
 562                                 info->metadata_ratio = intarg;
 563                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
 564                                        info->metadata_ratio);
 565                         } else {
 566                                 ret = -EINVAL;
 567                                 goto out;
 568                         }
 569                         break;
 570                 case Opt_discard:
 571                         btrfs_set_opt(info->mount_opt, DISCARD);
 572                         break;
 573                 case Opt_space_cache:
 574                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 575                         break;
 576                 case Opt_rescan_uuid_tree:
 577                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 578                         break;
 579                 case Opt_no_space_cache:
 580                         printk(KERN_INFO "btrfs: disabling disk space caching\n");
 581                         btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
 582                         break;
 583                 case Opt_inode_cache:
 584                         printk(KERN_INFO "btrfs: enabling inode map caching\n");
 585                         btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
 586                         break;
 587                 case Opt_clear_cache:
 588                         printk(KERN_INFO "btrfs: force clearing of disk cache\n");
 589                         btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
 590                         break;
 591                 case Opt_user_subvol_rm_allowed:
 592                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 593                         break;
 594                 case Opt_enospc_debug:
 595                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 596                         break;
 597                 case Opt_defrag:
 598                         printk(KERN_INFO "btrfs: enabling auto defrag\n");
 599                         btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
 600                         break;
 601                 case Opt_recovery:
 602                         printk(KERN_INFO "btrfs: enabling auto recovery\n");
 603                         btrfs_set_opt(info->mount_opt, RECOVERY);
 604                         break;
 605                 case Opt_skip_balance:
 606                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 607                         break;
 608 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 609                 case Opt_check_integrity_including_extent_data:
 610                         printk(KERN_INFO "btrfs: enabling check integrity"
 611                                " including extent data\n");
 612                         btrfs_set_opt(info->mount_opt,
 613                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 614                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 615                         break;
 616                 case Opt_check_integrity:
 617                         printk(KERN_INFO "btrfs: enabling check integrity\n");
 618                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 619                         break;
 620                 case Opt_check_integrity_print_mask:
 621                         ret = match_int(&args[0], &intarg);
 622                         if (ret) {
 623                                 goto out;
 624                         } else if (intarg >= 0) {
 625                                 info->check_integrity_print_mask = intarg;
 626                                 printk(KERN_INFO "btrfs:"
 627                                        " check_integrity_print_mask 0x%x\n",
 628                                        info->check_integrity_print_mask);
 629                         } else {
 630                                 ret = -EINVAL;
 631                                 goto out;
 632                         }
 633                         break;
 634 #else
 635                 case Opt_check_integrity_including_extent_data:
 636                 case Opt_check_integrity:
 637                 case Opt_check_integrity_print_mask:
 638                         printk(KERN_ERR "btrfs: support for check_integrity*"
 639                                " not compiled in!\n");
 640                         ret = -EINVAL;
 641                         goto out;
 642 #endif
 643                 case Opt_fatal_errors:
 644                         if (strcmp(args[0].from, "panic") == 0)
 645                                 btrfs_set_opt(info->mount_opt,
 646                                               PANIC_ON_FATAL_ERROR);
 647                         else if (strcmp(args[0].from, "bug") == 0)
 648                                 btrfs_clear_opt(info->mount_opt,
 649                                               PANIC_ON_FATAL_ERROR);
 650                         else {
 651                                 ret = -EINVAL;
 652                                 goto out;
 653                         }
 654                         break;
 655                 case Opt_commit_interval:
 656                         intarg = 0;
 657                         ret = match_int(&args[0], &intarg);
 658                         if (ret < 0) {
 659                                 printk(KERN_ERR
 660                                         "btrfs: invalid commit interval\n");
 661                                 ret = -EINVAL;
 662                                 goto out;
 663                         }
 664                         if (intarg > 0) {
 665                                 if (intarg > 300) {
 666                                         printk(KERN_WARNING
 667                                             "btrfs: excessive commit interval %d\n",
 668                                                         intarg);
 669                                 }
 670                                 info->commit_interval = intarg;
 671                         } else {
 672                                 printk(KERN_INFO
 673                                     "btrfs: using default commit interval %ds\n",
 674                                     BTRFS_DEFAULT_COMMIT_INTERVAL);
 675                                 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 676                         }
 677                         break;
 678                 case Opt_err:
 679                         printk(KERN_INFO "btrfs: unrecognized mount option "
 680                                "'%s'\n", p);
 681                         ret = -EINVAL;
 682                         goto out;
 683                 default:
 684                         break;
 685                 }
 686         }
 687 out:
 688         if (!ret && btrfs_test_opt(root, SPACE_CACHE))
 689                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
 690         kfree(orig);
 691         return ret;
 692 }
 693
 694 /*
 695  * Parse mount options that are required early in the mount process.
 696  *
 697  * All other options will be parsed on much later in the mount process and
 698  * only when we need to allocate a new super block.
 699  */
 700 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 701                 void *holder, char **subvol_name, u64 *subvol_objectid,
 702                 struct btrfs_fs_devices **fs_devices)
 703 {
 704         substring_t args[MAX_OPT_ARGS];
 705         char *device_name, *opts, *orig, *p;
 706         char *num = NULL;
 707         int error = 0;
 708
 709         if (!options)
 710                 return 0;
 711
 712         /*
 713          * strsep changes the string, duplicate it because parse_options
 714          * gets called twice
 715          */
 716         opts = kstrdup(options, GFP_KERNEL);
 717         if (!opts)
 718                 return -ENOMEM;
 719         orig = opts;
 720
 721         while ((p = strsep(&opts, ",")) != NULL) {
 722                 int token;
 723                 if (!*p)
 724                         continue;
 725
 726                 token = match_token(p, tokens, args);
 727                 switch (token) {
 728                 case Opt_subvol:
 729                         kfree(*subvol_name);
 730                         *subvol_name = match_strdup(&args[0]);
 731                         if (!*subvol_name) {
 732                                 error = -ENOMEM;
 733                                 goto out;
 734                         }
 735                         break;
 736                 case Opt_subvolid:
 737                         num = match_strdup(&args[0]);
 738                         if (num) {
 739                                 *subvol_objectid = memparse(num, NULL);
 740                                 kfree(num);
 741                                 /* we want the original fs_tree */
 742                                 if (!*subvol_objectid)
 743                                         *subvol_objectid =
 744                                                 BTRFS_FS_TREE_OBJECTID;
 745                         } else {
 746                                 error = -EINVAL;
 747                                 goto out;
 748                         }
 749                         break;
 750                 case Opt_subvolrootid:
 751                         printk(KERN_WARNING
 752                                 "btrfs: 'subvolrootid' mount option is deprecated and has no effect\n");
 753                         break;
 754                 case Opt_device:
 755                         device_name = match_strdup(&args[0]);
 756                         if (!device_name) {
 757                                 error = -ENOMEM;
 758                                 goto out;
 759                         }
 760                         error = btrfs_scan_one_device(device_name,
 761                                         flags, holder, fs_devices);
 762                         kfree(device_name);
 763                         if (error)
 764                                 goto out;
 765                         break;
 766                 default:
 767                         break;
 768                 }
 769         }
 770
 771 out:
 772         kfree(orig);
 773         return error;
 774 }
 775
 776 static struct dentry *get_default_root(struct super_block *sb,
 777                                        u64 subvol_objectid)
 778 {
 779         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 780         struct btrfs_root *root = fs_info->tree_root;
 781         struct btrfs_root *new_root;
 782         struct btrfs_dir_item *di;
 783         struct btrfs_path *path;
 784         struct btrfs_key location;
 785         struct inode *inode;
 786         u64 dir_id;
 787         int new = 0;
 788
 789         /*
 790          * We have a specific subvol we want to mount, just setup location and
 791          * go look up the root.
 792          */
 793         if (subvol_objectid) {
 794                 location.objectid = subvol_objectid;
 795                 location.type = BTRFS_ROOT_ITEM_KEY;
 796                 location.offset = (u64)-1;
 797                 goto find_root;
 798         }
 799
 800         path = btrfs_alloc_path();
 801         if (!path)
 802                 return ERR_PTR(-ENOMEM);
 803         path->leave_spinning = 1;
 804
 805         /*
 806          * Find the "default" dir item which points to the root item that we
 807          * will mount by default if we haven't been given a specific subvolume
 808          * to mount.
 809          */
 810         dir_id = btrfs_super_root_dir(fs_info->super_copy);
 811         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
 812         if (IS_ERR(di)) {
 813                 btrfs_free_path(path);
 814                 return ERR_CAST(di);
 815         }
 816         if (!di) {
 817                 /*
 818                  * Ok the default dir item isn't there.  This is weird since
 819                  * it's always been there, but don't freak out, just try and
 820                  * mount to root most subvolume.
 821                  */
 822                 btrfs_free_path(path);
 823                 dir_id = BTRFS_FIRST_FREE_OBJECTID;
 824                 new_root = fs_info->fs_root;
 825                 goto setup_root;
 826         }
 827
 828         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
 829         btrfs_free_path(path);
 830
 831 find_root:
 832         new_root = btrfs_read_fs_root_no_name(fs_info, &location);
 833         if (IS_ERR(new_root))
 834                 return ERR_CAST(new_root);
 835
 836         dir_id = btrfs_root_dirid(&new_root->root_item);
 837 setup_root:
 838         location.objectid = dir_id;
 839         location.type = BTRFS_INODE_ITEM_KEY;
 840         location.offset = 0;
 841
 842         inode = btrfs_iget(sb, &location, new_root, &new);
 843         if (IS_ERR(inode))
 844                 return ERR_CAST(inode);
 845
 846         /*
 847          * If we're just mounting the root most subvol put the inode and return
 848          * a reference to the dentry.  We will have already gotten a reference
 849          * to the inode in btrfs_fill_super so we're good to go.
 850          */
 851         if (!new && sb->s_root->d_inode == inode) {
 852                 iput(inode);
 853                 return dget(sb->s_root);
 854         }
 855
 856         return d_obtain_alias(inode);
 857 }
 858
 859 static int btrfs_fill_super(struct super_block *sb,
 860                             struct btrfs_fs_devices *fs_devices,
 861                             void *data, int silent)
 862 {
 863         struct inode *inode;
 864         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 865         struct btrfs_key key;
 866         int err;
 867
 868         sb->s_maxbytes = MAX_LFS_FILESIZE;
 869         sb->s_magic = BTRFS_SUPER_MAGIC;
 870         sb->s_op = &btrfs_super_ops;
 871         sb->s_d_op = &btrfs_dentry_operations;
 872         sb->s_export_op = &btrfs_export_ops;
 873         sb->s_xattr = btrfs_xattr_handlers;
 874         sb->s_time_gran = 1;
 875 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 876         sb->s_flags |= MS_POSIXACL;
 877 #endif
 878         sb->s_flags |= MS_I_VERSION;
 879         err = open_ctree(sb, fs_devices, (char *)data);
 880         if (err) {
 881                 printk("btrfs: open_ctree failed\n");
 882                 return err;
 883         }
 884
 885         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 886         key.type = BTRFS_INODE_ITEM_KEY;
 887         key.offset = 0;
 888         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
 889         if (IS_ERR(inode)) {
 890                 err = PTR_ERR(inode);
 891                 goto fail_close;
 892         }
 893
 894         sb->s_root = d_make_root(inode);
 895         if (!sb->s_root) {
 896                 err = -ENOMEM;
 897                 goto fail_close;
 898         }
 899
 900         save_mount_options(sb, data);
 901         cleancache_init_fs(sb);
 902         sb->s_flags |= MS_ACTIVE;
 903         return 0;
 904
 905 fail_close:
 906         close_ctree(fs_info->tree_root);
 907         return err;
 908 }
 909
 910 int btrfs_sync_fs(struct super_block *sb, int wait)
 911 {
 912         struct btrfs_trans_handle *trans;
 913         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 914         struct btrfs_root *root = fs_info->tree_root;
 915
 916         trace_btrfs_sync_fs(wait);
 917
 918         if (!wait) {
 919                 filemap_flush(fs_info->btree_inode->i_mapping);
 920                 return 0;
 921         }
 922
 923         btrfs_wait_ordered_roots(fs_info, -1);
 924
 925         trans = btrfs_attach_transaction_barrier(root);
 926         if (IS_ERR(trans)) {
 927                 /* no transaction, don't bother */
 928                 if (PTR_ERR(trans) == -ENOENT)
 929                         return 0;
 930                 return PTR_ERR(trans);
 931         }
 932         return btrfs_commit_transaction(trans, root);
 933 }
 934
 935 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
 936 {
 937         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
 938         struct btrfs_root *root = info->tree_root;
 939         char *compress_type;
 940
 941         if (btrfs_test_opt(root, DEGRADED))
 942                 seq_puts(seq, ",degraded");
 943         if (btrfs_test_opt(root, NODATASUM))
 944                 seq_puts(seq, ",nodatasum");
 945         if (btrfs_test_opt(root, NODATACOW))
 946                 seq_puts(seq, ",nodatacow");
 947         if (btrfs_test_opt(root, NOBARRIER))
 948                 seq_puts(seq, ",nobarrier");
 949         if (info->max_inline != 8192 * 1024)
 950                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
 951         if (info->alloc_start != 0)
 952                 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
 953         if (info->thread_pool_size !=  min_t(unsigned long,
 954                                              num_online_cpus() + 2, 8))
 955                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 956         if (btrfs_test_opt(root, COMPRESS)) {
 957                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
 958                         compress_type = "zlib";
 959                 else
 960                         compress_type = "lzo";
 961                 if (btrfs_test_opt(root, FORCE_COMPRESS))
 962                         seq_printf(seq, ",compress-force=%s", compress_type);
 963                 else
 964                         seq_printf(seq, ",compress=%s", compress_type);
 965         }
 966         if (btrfs_test_opt(root, NOSSD))
 967                 seq_puts(seq, ",nossd");
 968         if (btrfs_test_opt(root, SSD_SPREAD))
 969                 seq_puts(seq, ",ssd_spread");
 970         else if (btrfs_test_opt(root, SSD))
 971                 seq_puts(seq, ",ssd");
 972         if (btrfs_test_opt(root, NOTREELOG))
 973                 seq_puts(seq, ",notreelog");
 974         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 975                 seq_puts(seq, ",flushoncommit");
 976         if (btrfs_test_opt(root, DISCARD))
 977                 seq_puts(seq, ",discard");
 978         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 979                 seq_puts(seq, ",noacl");
 980         if (btrfs_test_opt(root, SPACE_CACHE))
 981                 seq_puts(seq, ",space_cache");
 982         else
 983                 seq_puts(seq, ",nospace_cache");
 984         if (btrfs_test_opt(root, RESCAN_UUID_TREE))
 985                 seq_puts(seq, ",rescan_uuid_tree");
 986         if (btrfs_test_opt(root, CLEAR_CACHE))
 987                 seq_puts(seq, ",clear_cache");
 988         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
 989                 seq_puts(seq, ",user_subvol_rm_allowed");
 990         if (btrfs_test_opt(root, ENOSPC_DEBUG))
 991                 seq_puts(seq, ",enospc_debug");
 992         if (btrfs_test_opt(root, AUTO_DEFRAG))
 993                 seq_puts(seq, ",autodefrag");
 994         if (btrfs_test_opt(root, INODE_MAP_CACHE))
 995                 seq_puts(seq, ",inode_cache");
 996         if (btrfs_test_opt(root, SKIP_BALANCE))
 997                 seq_puts(seq, ",skip_balance");
 998         if (btrfs_test_opt(root, RECOVERY))
 999                 seq_puts(seq, ",recovery");
1000 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1001         if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1002                 seq_puts(seq, ",check_int_data");
1003         else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1004                 seq_puts(seq, ",check_int");
1005         if (info->check_integrity_print_mask)
1006                 seq_printf(seq, ",check_int_print_mask=%d",
1007                                 info->check_integrity_print_mask);
1008 #endif
1009         if (info->metadata_ratio)
1010                 seq_printf(seq, ",metadata_ratio=%d",
1011                                 info->metadata_ratio);
1012         if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1013                 seq_puts(seq, ",fatal_errors=panic");
1014         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1015                 seq_printf(seq, ",commit=%d", info->commit_interval);
1016         return 0;
1017 }
1018
1019 static int btrfs_test_super(struct super_block *s, void *data)
1020 {
1021         struct btrfs_fs_info *p = data;
1022         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1023
1024         return fs_info->fs_devices == p->fs_devices;
1025 }
1026
1027 static int btrfs_set_super(struct super_block *s, void *data)
1028 {
1029         int err = set_anon_super(s, data);
1030         if (!err)
1031                 s->s_fs_info = data;
1032         return err;
1033 }
1034
1035 /*
1036  * subvolumes are identified by ino 256
1037  */
1038 static inline int is_subvolume_inode(struct inode *inode)
1039 {
1040         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1041                 return 1;
1042         return 0;
1043 }
1044
1045 /*
1046  * This will strip out the subvol=%s argument for an argument string and add
1047  * subvolid=0 to make sure we get the actual tree root for path walking to the
1048  * subvol we want.
1049  */
1050 static char *setup_root_args(char *args)
1051 {
1052         unsigned len = strlen(args) + 2 + 1;
1053         char *src, *dst, *buf;
1054
1055         /*
1056          * We need the same args as before, but with this substitution:
1057          * s!subvol=[^,]+!subvolid=0!
1058          *
1059          * Since the replacement string is up to 2 bytes longer than the
1060          * original, allocate strlen(args) + 2 + 1 bytes.
1061          */
1062
1063         src = strstr(args, "subvol=");
1064         /* This shouldn't happen, but just in case.. */
1065         if (!src)
1066                 return NULL;
1067
1068         buf = dst = kmalloc(len, GFP_NOFS);
1069         if (!buf)
1070                 return NULL;
1071
1072         /*
1073          * If the subvol= arg is not at the start of the string,
1074          * copy whatever precedes it into buf.
1075          */
1076         if (src != args) {
1077                 *src++ = '\0';
1078                 strcpy(buf, args);
1079                 dst += strlen(args);
1080         }
1081
1082         strcpy(dst, "subvolid=0");
1083         dst += strlen("subvolid=0");
1084
1085         /*
1086          * If there is a "," after the original subvol=... string,
1087          * copy that suffix into our buffer.  Otherwise, we're done.
1088          */
1089         src = strchr(src, ',');
1090         if (src)
1091                 strcpy(dst, src);
1092
1093         return buf;
1094 }
1095
1096 static struct dentry *mount_subvol(const char *subvol_name, int flags,
1097                                    const char *device_name, char *data)
1098 {
1099         struct dentry *root;
1100         struct vfsmount *mnt;
1101         char *newargs;
1102
1103         newargs = setup_root_args(data);
1104         if (!newargs)
1105                 return ERR_PTR(-ENOMEM);
1106         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
1107                              newargs);
1108         kfree(newargs);
1109         if (IS_ERR(mnt))
1110                 return ERR_CAST(mnt);
1111
1112         root = mount_subtree(mnt, subvol_name);
1113
1114         if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
1115                 struct super_block *s = root->d_sb;
1116                 dput(root);
1117                 root = ERR_PTR(-EINVAL);
1118                 deactivate_locked_super(s);
1119                 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
1120                                 subvol_name);
1121         }
1122
1123         return root;
1124 }
1125
1126 /*
1127  * Find a superblock for the given device / mount point.
1128  *
1129  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1130  *        for multiple device setup.  Make sure to keep it in sync.
1131  */
1132 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1133                 const char *device_name, void *data)
1134 {
1135         struct block_device *bdev = NULL;
1136         struct super_block *s;
1137         struct dentry *root;
1138         struct btrfs_fs_devices *fs_devices = NULL;
1139         struct btrfs_fs_info *fs_info = NULL;
1140         fmode_t mode = FMODE_READ;
1141         char *subvol_name = NULL;
1142         u64 subvol_objectid = 0;
1143         int error = 0;
1144
1145         if (!(flags & MS_RDONLY))
1146                 mode |= FMODE_WRITE;
1147
1148         error = btrfs_parse_early_options(data, mode, fs_type,
1149                                           &subvol_name, &subvol_objectid,
1150                                           &fs_devices);
1151         if (error) {
1152                 kfree(subvol_name);
1153                 return ERR_PTR(error);
1154         }
1155
1156         if (subvol_name) {
1157                 root = mount_subvol(subvol_name, flags, device_name, data);
1158                 kfree(subvol_name);
1159                 return root;
1160         }
1161
1162         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1163         if (error)
1164                 return ERR_PTR(error);
1165
1166         /*
1167          * Setup a dummy root and fs_info for test/set super.  This is because
1168          * we don't actually fill this stuff out until open_ctree, but we need
1169          * it for searching for existing supers, so this lets us do that and
1170          * then open_ctree will properly initialize everything later.
1171          */
1172         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1173         if (!fs_info)
1174                 return ERR_PTR(-ENOMEM);
1175
1176         fs_info->fs_devices = fs_devices;
1177
1178         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1179         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1180         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1181                 error = -ENOMEM;
1182                 goto error_fs_info;
1183         }
1184
1185         error = btrfs_open_devices(fs_devices, mode, fs_type);
1186         if (error)
1187                 goto error_fs_info;
1188
1189         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1190                 error = -EACCES;
1191                 goto error_close_devices;
1192         }
1193
1194         bdev = fs_devices->latest_bdev;
1195         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1196                  fs_info);
1197         if (IS_ERR(s)) {
1198                 error = PTR_ERR(s);
1199                 goto error_close_devices;
1200         }
1201
1202         if (s->s_root) {
1203                 btrfs_close_devices(fs_devices);
1204                 free_fs_info(fs_info);
1205                 if ((flags ^ s->s_flags) & MS_RDONLY)
1206                         error = -EBUSY;
1207         } else {
1208                 char b[BDEVNAME_SIZE];
1209
1210                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1211                 btrfs_sb(s)->bdev_holder = fs_type;
1212                 error = btrfs_fill_super(s, fs_devices, data,
1213                                          flags & MS_SILENT ? 1 : 0);
1214         }
1215
1216         root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
1217         if (IS_ERR(root))
1218                 deactivate_locked_super(s);
1219
1220         return root;
1221
1222 error_close_devices:
1223         btrfs_close_devices(fs_devices);
1224 error_fs_info:
1225         free_fs_info(fs_info);
1226         return ERR_PTR(error);
1227 }
1228
1229 static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit)
1230 {
1231         spin_lock_irq(&workers->lock);
1232         workers->max_workers = new_limit;
1233         spin_unlock_irq(&workers->lock);
1234 }
1235
1236 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1237                                      int new_pool_size, int old_pool_size)
1238 {
1239         if (new_pool_size == old_pool_size)
1240                 return;
1241
1242         fs_info->thread_pool_size = new_pool_size;
1243
1244         printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n",
1245                old_pool_size, new_pool_size);
1246
1247         btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
1248         btrfs_set_max_workers(&fs_info->workers, new_pool_size);
1249         btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
1250         btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
1251         btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
1252         btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
1253         btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size);
1254         btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size);
1255         btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size);
1256         btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size);
1257         btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size);
1258         btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
1259         btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size);
1260         btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
1261                               new_pool_size);
1262 }
1263
1264 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1265 {
1266         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1267 }
1268
1269 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1270                                        unsigned long old_opts, int flags)
1271 {
1272         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1273             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1274              (flags & MS_RDONLY))) {
1275                 /* wait for any defraggers to finish */
1276                 wait_event(fs_info->transaction_wait,
1277                            (atomic_read(&fs_info->defrag_running) == 0));
1278                 if (flags & MS_RDONLY)
1279                         sync_filesystem(fs_info->sb);
1280         }
1281 }
1282
1283 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1284                                          unsigned long old_opts)
1285 {
1286         /*
1287          * We need cleanup all defragable inodes if the autodefragment is
1288          * close or the fs is R/O.
1289          */
1290         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1291             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1292              (fs_info->sb->s_flags & MS_RDONLY))) {
1293                 btrfs_cleanup_defrag_inodes(fs_info);
1294         }
1295
1296         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1297 }
1298
1299 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1300 {
1301         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1302         struct btrfs_root *root = fs_info->tree_root;
1303         unsigned old_flags = sb->s_flags;
1304         unsigned long old_opts = fs_info->mount_opt;
1305         unsigned long old_compress_type = fs_info->compress_type;
1306         u64 old_max_inline = fs_info->max_inline;
1307         u64 old_alloc_start = fs_info->alloc_start;
1308         int old_thread_pool_size = fs_info->thread_pool_size;
1309         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1310         int ret;
1311
1312         btrfs_remount_prepare(fs_info);
1313
1314         ret = btrfs_parse_options(root, data);
1315         if (ret) {
1316                 ret = -EINVAL;
1317                 goto restore;
1318         }
1319
1320         btrfs_remount_begin(fs_info, old_opts, *flags);
1321         btrfs_resize_thread_pool(fs_info,
1322                 fs_info->thread_pool_size, old_thread_pool_size);
1323
1324         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1325                 goto out;
1326
1327         if (*flags & MS_RDONLY) {
1328                 /*
1329                  * this also happens on 'umount -rf' or on shutdown, when
1330                  * the filesystem is busy.
1331                  */
1332
1333                 /* wait for the uuid_scan task to finish */
1334                 down(&fs_info->uuid_tree_rescan_sem);
1335                 /* avoid complains from lockdep et al. */
1336                 up(&fs_info->uuid_tree_rescan_sem);
1337
1338                 sb->s_flags |= MS_RDONLY;
1339
1340                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1341                 btrfs_scrub_cancel(fs_info);
1342                 btrfs_pause_balance(fs_info);
1343
1344                 ret = btrfs_commit_super(root);
1345                 if (ret)
1346                         goto restore;
1347         } else {
1348                 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1349                         btrfs_err(fs_info,
1350                                 "Remounting read-write after error is not allowed\n");
1351                         ret = -EINVAL;
1352                         goto restore;
1353                 }
1354                 if (fs_info->fs_devices->rw_devices == 0) {
1355                         ret = -EACCES;
1356                         goto restore;
1357                 }
1358
1359                 if (fs_info->fs_devices->missing_devices >
1360                      fs_info->num_tolerated_disk_barrier_failures &&
1361                     !(*flags & MS_RDONLY)) {
1362                         printk(KERN_WARNING
1363                                "Btrfs: too many missing devices, writeable remount is not allowed\n");
1364                         ret = -EACCES;
1365                         goto restore;
1366                 }
1367
1368                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1369                         ret = -EINVAL;
1370                         goto restore;
1371                 }
1372
1373                 ret = btrfs_cleanup_fs_roots(fs_info);
1374                 if (ret)
1375                         goto restore;
1376
1377                 /* recover relocation */
1378                 ret = btrfs_recover_relocation(root);
1379                 if (ret)
1380                         goto restore;
1381
1382                 ret = btrfs_resume_balance_async(fs_info);
1383                 if (ret)
1384                         goto restore;
1385
1386                 ret = btrfs_resume_dev_replace_async(fs_info);
1387                 if (ret) {
1388                         pr_warn("btrfs: failed to resume dev_replace\n");
1389                         goto restore;
1390                 }
1391
1392                 if (!fs_info->uuid_root) {
1393                         pr_info("btrfs: creating UUID tree\n");
1394                         ret = btrfs_create_uuid_tree(fs_info);
1395                         if (ret) {
1396                                 pr_warn("btrfs: failed to create the uuid tree"
1397                                         "%d\n", ret);
1398                                 goto restore;
1399                         }
1400                 }
1401                 sb->s_flags &= ~MS_RDONLY;
1402         }
1403 out:
1404         btrfs_remount_cleanup(fs_info, old_opts);
1405         return 0;
1406
1407 restore:
1408         /* We've hit an error - don't reset MS_RDONLY */
1409         if (sb->s_flags & MS_RDONLY)
1410                 old_flags |= MS_RDONLY;
1411         sb->s_flags = old_flags;
1412         fs_info->mount_opt = old_opts;
1413         fs_info->compress_type = old_compress_type;
1414         fs_info->max_inline = old_max_inline;
1415         mutex_lock(&fs_info->chunk_mutex);
1416         fs_info->alloc_start = old_alloc_start;
1417         mutex_unlock(&fs_info->chunk_mutex);
1418         btrfs_resize_thread_pool(fs_info,
1419                 old_thread_pool_size, fs_info->thread_pool_size);
1420         fs_info->metadata_ratio = old_metadata_ratio;
1421         btrfs_remount_cleanup(fs_info, old_opts);
1422         return ret;
1423 }
1424
1425 /* Used to sort the devices by max_avail(descending sort) */
1426 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1427                                        const void *dev_info2)
1428 {
1429         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1430             ((struct btrfs_device_info *)dev_info2)->max_avail)
1431                 return -1;
1432         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1433                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1434                 return 1;
1435         else
1436         return 0;
1437 }
1438
1439 /*
1440  * sort the devices by max_avail, in which max free extent size of each device
1441  * is stored.(Descending Sort)
1442  */
1443 static inline void btrfs_descending_sort_devices(
1444                                         struct btrfs_device_info *devices,
1445                                         size_t nr_devices)
1446 {
1447         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1448              btrfs_cmp_device_free_bytes, NULL);
1449 }
1450
1451 /*
1452  * The helper to calc the free space on the devices that can be used to store
1453  * file data.
1454  */
1455 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1456 {
1457         struct btrfs_fs_info *fs_info = root->fs_info;
1458         struct btrfs_device_info *devices_info;
1459         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1460         struct btrfs_device *device;
1461         u64 skip_space;
1462         u64 type;
1463         u64 avail_space;
1464         u64 used_space;
1465         u64 min_stripe_size;
1466         int min_stripes = 1, num_stripes = 1;
1467         int i = 0, nr_devices;
1468         int ret;
1469
1470         nr_devices = fs_info->fs_devices->open_devices;
1471         BUG_ON(!nr_devices);
1472
1473         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1474                                GFP_NOFS);
1475         if (!devices_info)
1476                 return -ENOMEM;
1477
1478         /* calc min stripe number for data space alloction */
1479         type = btrfs_get_alloc_profile(root, 1);
1480         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1481                 min_stripes = 2;
1482                 num_stripes = nr_devices;
1483         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1484                 min_stripes = 2;
1485                 num_stripes = 2;
1486         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1487                 min_stripes = 4;
1488                 num_stripes = 4;
1489         }
1490
1491         if (type & BTRFS_BLOCK_GROUP_DUP)
1492                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1493         else
1494                 min_stripe_size = BTRFS_STRIPE_LEN;
1495
1496         list_for_each_entry(device, &fs_devices->devices, dev_list) {
1497                 if (!device->in_fs_metadata || !device->bdev ||
1498                     device->is_tgtdev_for_dev_replace)
1499                         continue;
1500
1501                 avail_space = device->total_bytes - device->bytes_used;
1502
1503                 /* align with stripe_len */
1504                 do_div(avail_space, BTRFS_STRIPE_LEN);
1505                 avail_space *= BTRFS_STRIPE_LEN;
1506
1507                 /*
1508                  * In order to avoid overwritting the superblock on the drive,
1509                  * btrfs starts at an offset of at least 1MB when doing chunk
1510                  * allocation.
1511                  */
1512                 skip_space = 1024 * 1024;
1513
1514                 /* user can set the offset in fs_info->alloc_start. */
1515                 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1516                     device->total_bytes)
1517                         skip_space = max(fs_info->alloc_start, skip_space);
1518
1519                 /*
1520                  * btrfs can not use the free space in [0, skip_space - 1],
1521                  * we must subtract it from the total. In order to implement
1522                  * it, we account the used space in this range first.
1523                  */
1524                 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1525                                                      &used_space);
1526                 if (ret) {
1527                         kfree(devices_info);
1528                         return ret;
1529                 }
1530
1531                 /* calc the free space in [0, skip_space - 1] */
1532                 skip_space -= used_space;
1533
1534                 /*
1535                  * we can use the free space in [0, skip_space - 1], subtract
1536                  * it from the total.
1537                  */
1538                 if (avail_space && avail_space >= skip_space)
1539                         avail_space -= skip_space;
1540                 else
1541                         avail_space = 0;
1542
1543                 if (avail_space < min_stripe_size)
1544                         continue;
1545
1546                 devices_info[i].dev = device;
1547                 devices_info[i].max_avail = avail_space;
1548
1549                 i++;
1550         }
1551
1552         nr_devices = i;
1553
1554         btrfs_descending_sort_devices(devices_info, nr_devices);
1555
1556         i = nr_devices - 1;
1557         avail_space = 0;
1558         while (nr_devices >= min_stripes) {
1559                 if (num_stripes > nr_devices)
1560                         num_stripes = nr_devices;
1561
1562                 if (devices_info[i].max_avail >= min_stripe_size) {
1563                         int j;
1564                         u64 alloc_size;
1565
1566                         avail_space += devices_info[i].max_avail * num_stripes;
1567                         alloc_size = devices_info[i].max_avail;
1568                         for (j = i + 1 - num_stripes; j <= i; j++)
1569                                 devices_info[j].max_avail -= alloc_size;
1570                 }
1571                 i--;
1572                 nr_devices--;
1573         }
1574
1575         kfree(devices_info);
1576         *free_bytes = avail_space;
1577         return 0;
1578 }
1579
1580 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1581 {
1582         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1583         struct btrfs_super_block *disk_super = fs_info->super_copy;
1584         struct list_head *head = &fs_info->space_info;
1585         struct btrfs_space_info *found;
1586         u64 total_used = 0;
1587         u64 total_free_data = 0;
1588         int bits = dentry->d_sb->s_blocksize_bits;
1589         __be32 *fsid = (__be32 *)fs_info->fsid;
1590         int ret;
1591
1592         /* holding chunk_muext to avoid allocating new chunks */
1593         mutex_lock(&fs_info->chunk_mutex);
1594         rcu_read_lock();
1595         list_for_each_entry_rcu(found, head, list) {
1596                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1597                         total_free_data += found->disk_total - found->disk_used;
1598                         total_free_data -=
1599                                 btrfs_account_ro_block_groups_free_space(found);
1600                 }
1601
1602                 total_used += found->disk_used;
1603         }
1604         rcu_read_unlock();
1605
1606         buf->f_namelen = BTRFS_NAME_LEN;
1607         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1608         buf->f_bfree = buf->f_blocks - (total_used >> bits);
1609         buf->f_bsize = dentry->d_sb->s_blocksize;
1610         buf->f_type = BTRFS_SUPER_MAGIC;
1611         buf->f_bavail = total_free_data;
1612         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1613         if (ret) {
1614                 mutex_unlock(&fs_info->chunk_mutex);
1615                 return ret;
1616         }
1617         buf->f_bavail += total_free_data;
1618         buf->f_bavail = buf->f_bavail >> bits;
1619         mutex_unlock(&fs_info->chunk_mutex);
1620
1621         /* We treat it as constant endianness (it doesn't matter _which_)
1622            because we want the fsid to come out the same whether mounted
1623            on a big-endian or little-endian host */
1624         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1625         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1626         /* Mask in the root object ID too, to disambiguate subvols */
1627         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1628         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1629
1630         return 0;
1631 }
1632
1633 static void btrfs_kill_super(struct super_block *sb)
1634 {
1635         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1636         kill_anon_super(sb);
1637         free_fs_info(fs_info);
1638 }
1639
1640 static struct file_system_type btrfs_fs_type = {
1641         .owner          = THIS_MODULE,
1642         .name           = "btrfs",
1643         .mount          = btrfs_mount,
1644         .kill_sb        = btrfs_kill_super,
1645         .fs_flags       = FS_REQUIRES_DEV,
1646 };
1647 MODULE_ALIAS_FS("btrfs");
1648
1649 /*
1650  * used by btrfsctl to scan devices when no FS is mounted
1651  */
1652 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1653                                 unsigned long arg)
1654 {
1655         struct btrfs_ioctl_vol_args *vol;
1656         struct btrfs_fs_devices *fs_devices;
1657         int ret = -ENOTTY;
1658
1659         if (!capable(CAP_SYS_ADMIN))
1660                 return -EPERM;
1661
1662         vol = memdup_user((void __user *)arg, sizeof(*vol));
1663         if (IS_ERR(vol))
1664                 return PTR_ERR(vol);
1665
1666         switch (cmd) {
1667         case BTRFS_IOC_SCAN_DEV:
1668                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1669                                             &btrfs_fs_type, &fs_devices);
1670                 break;
1671         case BTRFS_IOC_DEVICES_READY:
1672                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1673                                             &btrfs_fs_type, &fs_devices);
1674                 if (ret)
1675                         break;
1676                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
1677                 break;
1678         }
1679
1680         kfree(vol);
1681         return ret;
1682 }
1683
1684 static int btrfs_freeze(struct super_block *sb)
1685 {
1686         struct btrfs_trans_handle *trans;
1687         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
1688
1689         trans = btrfs_attach_transaction_barrier(root);
1690         if (IS_ERR(trans)) {
1691                 /* no transaction, don't bother */
1692                 if (PTR_ERR(trans) == -ENOENT)
1693                         return 0;
1694                 return PTR_ERR(trans);
1695         }
1696         return btrfs_commit_transaction(trans, root);
1697 }
1698
1699 static int btrfs_unfreeze(struct super_block *sb)
1700 {
1701         return 0;
1702 }
1703
1704 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
1705 {
1706         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
1707         struct btrfs_fs_devices *cur_devices;
1708         struct btrfs_device *dev, *first_dev = NULL;
1709         struct list_head *head;
1710         struct rcu_string *name;
1711
1712         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1713         cur_devices = fs_info->fs_devices;
1714         while (cur_devices) {
1715                 head = &cur_devices->devices;
1716                 list_for_each_entry(dev, head, dev_list) {
1717                         if (dev->missing)
1718                                 continue;
1719                         if (!first_dev || dev->devid < first_dev->devid)
1720                                 first_dev = dev;
1721                 }
1722                 cur_devices = cur_devices->seed;
1723         }
1724
1725         if (first_dev) {
1726                 rcu_read_lock();
1727                 name = rcu_dereference(first_dev->name);
1728                 seq_escape(m, name->str, " \t\n\\");
1729                 rcu_read_unlock();
1730         } else {
1731                 WARN_ON(1);
1732         }
1733         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1734         return 0;
1735 }
1736
1737 static const struct super_operations btrfs_super_ops = {
1738         .drop_inode     = btrfs_drop_inode,
1739         .evict_inode    = btrfs_evict_inode,
1740         .put_super      = btrfs_put_super,
1741         .sync_fs        = btrfs_sync_fs,
1742         .show_options   = btrfs_show_options,
1743         .show_devname   = btrfs_show_devname,
1744         .write_inode    = btrfs_write_inode,
1745         .alloc_inode    = btrfs_alloc_inode,
1746         .destroy_inode  = btrfs_destroy_inode,
1747         .statfs         = btrfs_statfs,
1748         .remount_fs     = btrfs_remount,
1749         .freeze_fs      = btrfs_freeze,
1750         .unfreeze_fs    = btrfs_unfreeze,
1751 };
1752
1753 static const struct file_operations btrfs_ctl_fops = {
1754         .unlocked_ioctl  = btrfs_control_ioctl,
1755         .compat_ioctl = btrfs_control_ioctl,
1756         .owner   = THIS_MODULE,
1757         .llseek = noop_llseek,
1758 };
1759
1760 static struct miscdevice btrfs_misc = {
1761         .minor          = BTRFS_MINOR,
1762         .name           = "btrfs-control",
1763         .fops           = &btrfs_ctl_fops
1764 };
1765
1766 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1767 MODULE_ALIAS("devname:btrfs-control");
1768
1769 static int btrfs_interface_init(void)
1770 {
1771         return misc_register(&btrfs_misc);
1772 }
1773
1774 static void btrfs_interface_exit(void)
1775 {
1776         if (misc_deregister(&btrfs_misc) < 0)
1777                 printk(KERN_INFO "btrfs: misc_deregister failed for control device\n");
1778 }
1779
1780 static void btrfs_print_info(void)
1781 {
1782         printk(KERN_INFO "Btrfs loaded"
1783 #ifdef CONFIG_BTRFS_DEBUG
1784                         ", debug=on"
1785 #endif
1786 #ifdef CONFIG_BTRFS_ASSERT
1787                         ", assert=on"
1788 #endif
1789 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1790                         ", integrity-checker=on"
1791 #endif
1792                         "\n");
1793 }
1794
1795 static int btrfs_run_sanity_tests(void)
1796 {
1797         int ret;
1798
1799         ret = btrfs_init_test_fs();
1800         if (ret)
1801                 return ret;
1802
1803         ret = btrfs_test_free_space_cache();
1804         if (ret)
1805                 goto out;
1806         ret = btrfs_test_extent_buffer_operations();
1807         if (ret)
1808                 goto out;
1809         ret = btrfs_test_extent_io();
1810         if (ret)
1811                 goto out;
1812         ret = btrfs_test_inodes();
1813 out:
1814         btrfs_destroy_test_fs();
1815         return ret;
1816 }
1817
1818 static int __init init_btrfs_fs(void)
1819 {
1820         int err;
1821
1822         err = btrfs_init_sysfs();
1823         if (err)
1824                 return err;
1825
1826         btrfs_init_compress();
1827
1828         err = btrfs_init_cachep();
1829         if (err)
1830                 goto free_compress;
1831
1832         err = extent_io_init();
1833         if (err)
1834                 goto free_cachep;
1835
1836         err = extent_map_init();
1837         if (err)
1838                 goto free_extent_io;
1839
1840         err = ordered_data_init();
1841         if (err)
1842                 goto free_extent_map;
1843
1844         err = btrfs_delayed_inode_init();
1845         if (err)
1846                 goto free_ordered_data;
1847
1848         err = btrfs_auto_defrag_init();
1849         if (err)
1850                 goto free_delayed_inode;
1851
1852         err = btrfs_delayed_ref_init();
1853         if (err)
1854                 goto free_auto_defrag;
1855
1856         err = btrfs_prelim_ref_init();
1857         if (err)
1858                 goto free_prelim_ref;
1859
1860         err = btrfs_interface_init();
1861         if (err)
1862                 goto free_delayed_ref;
1863
1864         btrfs_init_lockdep();
1865
1866         btrfs_print_info();
1867
1868         err = btrfs_run_sanity_tests();
1869         if (err)
1870                 goto unregister_ioctl;
1871
1872         err = register_filesystem(&btrfs_fs_type);
1873         if (err)
1874                 goto unregister_ioctl;
1875
1876         return 0;
1877
1878 unregister_ioctl:
1879         btrfs_interface_exit();
1880 free_prelim_ref:
1881         btrfs_prelim_ref_exit();
1882 free_delayed_ref:
1883         btrfs_delayed_ref_exit();
1884 free_auto_defrag:
1885         btrfs_auto_defrag_exit();
1886 free_delayed_inode:
1887         btrfs_delayed_inode_exit();
1888 free_ordered_data:
1889         ordered_data_exit();
1890 free_extent_map:
1891         extent_map_exit();
1892 free_extent_io:
1893         extent_io_exit();
1894 free_cachep:
1895         btrfs_destroy_cachep();
1896 free_compress:
1897         btrfs_exit_compress();
1898         btrfs_exit_sysfs();
1899         return err;
1900 }
1901
1902 static void __exit exit_btrfs_fs(void)
1903 {
1904         btrfs_destroy_cachep();
1905         btrfs_delayed_ref_exit();
1906         btrfs_auto_defrag_exit();
1907         btrfs_delayed_inode_exit();
1908         btrfs_prelim_ref_exit();
1909         ordered_data_exit();
1910         extent_map_exit();
1911         extent_io_exit();
1912         btrfs_interface_exit();
1913         unregister_filesystem(&btrfs_fs_type);
1914         btrfs_exit_sysfs();
1915         btrfs_cleanup_fs_uuids();
1916         btrfs_exit_compress();
1917 }
1918
1919 module_init(init_btrfs_fs)
1920 module_exit(exit_btrfs_fs)
1921
1922 MODULE_LICENSE("GPL");