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 "hash.h"
  52 #include "props.h"
  53 #include "xattr.h"
  54 #include "volumes.h"
  55 #include "export.h"
  56 #include "compression.h"
  57 #include "rcu-string.h"
  58 #include "dev-replace.h"
  59 #include "free-space-cache.h"
  60 #include "backref.h"
  61 #include "tests/btrfs-tests.h"
  62
  63 #include "qgroup.h"
  64 #define CREATE_TRACE_POINTS
  65 #include <trace/events/btrfs.h>
  66
  67 static const struct super_operations btrfs_super_ops;
  68 static struct file_system_type btrfs_fs_type;
  69
  70 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  71
  72 const char *btrfs_decode_error(int errno)
  73 {
  74         char *errstr = "unknown";
  75
  76         switch (errno) {
  77         case -EIO:
  78                 errstr = "IO failure";
  79                 break;
  80         case -ENOMEM:
  81                 errstr = "Out of memory";
  82                 break;
  83         case -EROFS:
  84                 errstr = "Readonly filesystem";
  85                 break;
  86         case -EEXIST:
  87                 errstr = "Object already exists";
  88                 break;
  89         case -ENOSPC:
  90                 errstr = "No space left";
  91                 break;
  92         case -ENOENT:
  93                 errstr = "No such entry";
  94                 break;
  95         }
  96
  97         return errstr;
  98 }
  99
 100 /* btrfs handle error by forcing the filesystem readonly */
 101 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 102 {
 103         struct super_block *sb = fs_info->sb;
 104
 105         if (sb->s_flags & MS_RDONLY)
 106                 return;
 107
 108         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 109                 sb->s_flags |= MS_RDONLY;
 110                 btrfs_info(fs_info, "forced readonly");
 111                 /*
 112                  * Note that a running device replace operation is not
 113                  * canceled here although there is no way to update
 114                  * the progress. It would add the risk of a deadlock,
 115                  * therefore the canceling is omitted. The only penalty
 116                  * is that some I/O remains active until the procedure
 117                  * completes. The next time when the filesystem is
 118                  * mounted writeable again, the device replace
 119                  * operation continues.
 120                  */
 121         }
 122 }
 123
 124 /*
 125  * __btrfs_handle_fs_error decodes expected errors from the caller and
 126  * invokes the approciate error response.
 127  */
 128 __cold
 129 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 130                        unsigned int line, int errno, const char *fmt, ...)
 131 {
 132         struct super_block *sb = fs_info->sb;
 133 #ifdef CONFIG_PRINTK
 134         const char *errstr;
 135 #endif
 136
 137         /*
 138          * Special case: if the error is EROFS, and we're already
 139          * under MS_RDONLY, then it is safe here.
 140          */
 141         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 142                 return;
 143
 144 #ifdef CONFIG_PRINTK
 145         errstr = btrfs_decode_error(errno);
 146         if (fmt) {
 147                 struct va_format vaf;
 148                 va_list args;
 149
 150                 va_start(args, fmt);
 151                 vaf.fmt = fmt;
 152                 vaf.va = &args;
 153
 154                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 155                         sb->s_id, function, line, errno, errstr, &vaf);
 156                 va_end(args);
 157         } else {
 158                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 159                         sb->s_id, function, line, errno, errstr);
 160         }
 161 #endif
 162
 163         /*
 164          * Today we only save the error info to memory.  Long term we'll
 165          * also send it down to the disk
 166          */
 167         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 168
 169         /* Don't go through full error handling during mount */
 170         if (sb->s_flags & MS_BORN)
 171                 btrfs_handle_error(fs_info);
 172 }
 173
 174 #ifdef CONFIG_PRINTK
 175 static const char * const logtypes[] = {
 176         "emergency",
 177         "alert",
 178         "critical",
 179         "error",
 180         "warning",
 181         "notice",
 182         "info",
 183         "debug",
 184 };
 185
 186
 187 /*
 188  * Use one ratelimit state per log level so that a flood of less important
 189  * messages doesn't cause more important ones to be dropped.
 190  */
 191 static struct ratelimit_state printk_limits[] = {
 192         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 193         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 194         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 195         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 196         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 197         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 198         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 199         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 200 };
 201
 202 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 203 {
 204         struct super_block *sb = fs_info->sb;
 205         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1];
 206         struct va_format vaf;
 207         va_list args;
 208         const char *type = NULL;
 209         int kern_level;
 210         struct ratelimit_state *ratelimit;
 211
 212         va_start(args, fmt);
 213
 214         while ((kern_level = printk_get_level(fmt)) != 0) {
 215                 size_t size = printk_skip_level(fmt) - fmt;
 216
 217                 if (kern_level >= '0' && kern_level <= '7') {
 218                         memcpy(lvl, fmt,  size);
 219                         lvl[size] = '\0';
 220                         type = logtypes[kern_level - '0'];
 221                         ratelimit = &printk_limits[kern_level - '0'];
 222                 }
 223                 fmt += size;
 224         }
 225
 226         if (!type) {
 227                 *lvl = '\0';
 228                 type = logtypes[4];
 229                 ratelimit = &printk_limits[4];
 230         }
 231
 232         vaf.fmt = fmt;
 233         vaf.va = &args;
 234
 235         if (__ratelimit(ratelimit))
 236                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
 237
 238         va_end(args);
 239 }
 240 #endif
 241
 242 /*
 243  * We only mark the transaction aborted and then set the file system read-only.
 244  * This will prevent new transactions from starting or trying to join this
 245  * one.
 246  *
 247  * This means that error recovery at the call site is limited to freeing
 248  * any local memory allocations and passing the error code up without
 249  * further cleanup. The transaction should complete as it normally would
 250  * in the call path but will return -EIO.
 251  *
 252  * We'll complete the cleanup in btrfs_end_transaction and
 253  * btrfs_commit_transaction.
 254  */
 255 __cold
 256 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 257                                const char *function,
 258                                unsigned int line, int errno)
 259 {
 260         struct btrfs_fs_info *fs_info = trans->fs_info;
 261
 262         trans->aborted = errno;
 263         /* Nothing used. The other threads that have joined this
 264          * transaction may be able to continue. */
 265         if (!trans->dirty && list_empty(&trans->new_bgs)) {
 266                 const char *errstr;
 267
 268                 errstr = btrfs_decode_error(errno);
 269                 btrfs_warn(fs_info,
 270                            "%s:%d: Aborting unused transaction(%s).",
 271                            function, line, errstr);
 272                 return;
 273         }
 274         ACCESS_ONCE(trans->transaction->aborted) = errno;
 275         /* Wake up anybody who may be waiting on this transaction */
 276         wake_up(&fs_info->transaction_wait);
 277         wake_up(&fs_info->transaction_blocked_wait);
 278         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 279 }
 280 /*
 281  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 282  * issues an alert, and either panics or BUGs, depending on mount options.
 283  */
 284 __cold
 285 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 286                    unsigned int line, int errno, const char *fmt, ...)
 287 {
 288         char *s_id = "<unknown>";
 289         const char *errstr;
 290         struct va_format vaf = { .fmt = fmt };
 291         va_list args;
 292
 293         if (fs_info)
 294                 s_id = fs_info->sb->s_id;
 295
 296         va_start(args, fmt);
 297         vaf.va = &args;
 298
 299         errstr = btrfs_decode_error(errno);
 300         if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
 301                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 302                         s_id, function, line, &vaf, errno, errstr);
 303
 304         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 305                    function, line, &vaf, errno, errstr);
 306         va_end(args);
 307         /* Caller calls BUG() */
 308 }
 309
 310 static void btrfs_put_super(struct super_block *sb)
 311 {
 312         close_ctree(btrfs_sb(sb)->tree_root);
 313 }
 314
 315 enum {
 316         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 317         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 318         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 319         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 320         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 321         Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 322         Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 323         Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 324         Opt_skip_balance, Opt_check_integrity,
 325         Opt_check_integrity_including_extent_data,
 326         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 327         Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
 328         Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
 329         Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
 330         Opt_nologreplay, Opt_norecovery,
 331 #ifdef CONFIG_BTRFS_DEBUG
 332         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 333 #endif
 334         Opt_err,
 335 };
 336
 337 static const match_table_t tokens = {
 338         {Opt_degraded, "degraded"},
 339         {Opt_subvol, "subvol=%s"},
 340         {Opt_subvolid, "subvolid=%s"},
 341         {Opt_device, "device=%s"},
 342         {Opt_nodatasum, "nodatasum"},
 343         {Opt_datasum, "datasum"},
 344         {Opt_nodatacow, "nodatacow"},
 345         {Opt_datacow, "datacow"},
 346         {Opt_nobarrier, "nobarrier"},
 347         {Opt_barrier, "barrier"},
 348         {Opt_max_inline, "max_inline=%s"},
 349         {Opt_alloc_start, "alloc_start=%s"},
 350         {Opt_thread_pool, "thread_pool=%d"},
 351         {Opt_compress, "compress"},
 352         {Opt_compress_type, "compress=%s"},
 353         {Opt_compress_force, "compress-force"},
 354         {Opt_compress_force_type, "compress-force=%s"},
 355         {Opt_ssd, "ssd"},
 356         {Opt_ssd_spread, "ssd_spread"},
 357         {Opt_nossd, "nossd"},
 358         {Opt_acl, "acl"},
 359         {Opt_noacl, "noacl"},
 360         {Opt_notreelog, "notreelog"},
 361         {Opt_treelog, "treelog"},
 362         {Opt_nologreplay, "nologreplay"},
 363         {Opt_norecovery, "norecovery"},
 364         {Opt_flushoncommit, "flushoncommit"},
 365         {Opt_noflushoncommit, "noflushoncommit"},
 366         {Opt_ratio, "metadata_ratio=%d"},
 367         {Opt_discard, "discard"},
 368         {Opt_nodiscard, "nodiscard"},
 369         {Opt_space_cache, "space_cache"},
 370         {Opt_space_cache_version, "space_cache=%s"},
 371         {Opt_clear_cache, "clear_cache"},
 372         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 373         {Opt_enospc_debug, "enospc_debug"},
 374         {Opt_noenospc_debug, "noenospc_debug"},
 375         {Opt_subvolrootid, "subvolrootid=%d"},
 376         {Opt_defrag, "autodefrag"},
 377         {Opt_nodefrag, "noautodefrag"},
 378         {Opt_inode_cache, "inode_cache"},
 379         {Opt_noinode_cache, "noinode_cache"},
 380         {Opt_no_space_cache, "nospace_cache"},
 381         {Opt_recovery, "recovery"}, /* deprecated */
 382         {Opt_usebackuproot, "usebackuproot"},
 383         {Opt_skip_balance, "skip_balance"},
 384         {Opt_check_integrity, "check_int"},
 385         {Opt_check_integrity_including_extent_data, "check_int_data"},
 386         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 387         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 388         {Opt_fatal_errors, "fatal_errors=%s"},
 389         {Opt_commit_interval, "commit=%d"},
 390 #ifdef CONFIG_BTRFS_DEBUG
 391         {Opt_fragment_data, "fragment=data"},
 392         {Opt_fragment_metadata, "fragment=metadata"},
 393         {Opt_fragment_all, "fragment=all"},
 394 #endif
 395         {Opt_err, NULL},
 396 };
 397
 398 /*
 399  * Regular mount options parser.  Everything that is needed only when
 400  * reading in a new superblock is parsed here.
 401  * XXX JDM: This needs to be cleaned up for remount.
 402  */
 403 int btrfs_parse_options(struct btrfs_root *root, char *options,
 404                         unsigned long new_flags)
 405 {
 406         struct btrfs_fs_info *info = root->fs_info;
 407         substring_t args[MAX_OPT_ARGS];
 408         char *p, *num, *orig = NULL;
 409         u64 cache_gen;
 410         int intarg;
 411         int ret = 0;
 412         char *compress_type;
 413         bool compress_force = false;
 414         enum btrfs_compression_type saved_compress_type;
 415         bool saved_compress_force;
 416         int no_compress = 0;
 417
 418         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 419         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
 420                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 421         else if (cache_gen)
 422                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 423
 424         /*
 425          * Even the options are empty, we still need to do extra check
 426          * against new flags
 427          */
 428         if (!options)
 429                 goto check;
 430
 431         /*
 432          * strsep changes the string, duplicate it because parse_options
 433          * gets called twice
 434          */
 435         options = kstrdup(options, GFP_NOFS);
 436         if (!options)
 437                 return -ENOMEM;
 438
 439         orig = options;
 440
 441         while ((p = strsep(&options, ",")) != NULL) {
 442                 int token;
 443                 if (!*p)
 444                         continue;
 445
 446                 token = match_token(p, tokens, args);
 447                 switch (token) {
 448                 case Opt_degraded:
 449                         btrfs_info(root->fs_info, "allowing degraded mounts");
 450                         btrfs_set_opt(info->mount_opt, DEGRADED);
 451                         break;
 452                 case Opt_subvol:
 453                 case Opt_subvolid:
 454                 case Opt_subvolrootid:
 455                 case Opt_device:
 456                         /*
 457                          * These are parsed by btrfs_parse_early_options
 458                          * and can be happily ignored here.
 459                          */
 460                         break;
 461                 case Opt_nodatasum:
 462                         btrfs_set_and_info(info, NODATASUM,
 463                                            "setting nodatasum");
 464                         break;
 465                 case Opt_datasum:
 466                         if (btrfs_test_opt(info, NODATASUM)) {
 467                                 if (btrfs_test_opt(info, NODATACOW))
 468                                         btrfs_info(root->fs_info,
 469                                                    "setting datasum, datacow enabled");
 470                                 else
 471                                         btrfs_info(root->fs_info,
 472                                                    "setting datasum");
 473                         }
 474                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 475                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 476                         break;
 477                 case Opt_nodatacow:
 478                         if (!btrfs_test_opt(info, NODATACOW)) {
 479                                 if (!btrfs_test_opt(info, COMPRESS) ||
 480                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 481                                         btrfs_info(root->fs_info,
 482                                                    "setting nodatacow, compression disabled");
 483                                 } else {
 484                                         btrfs_info(root->fs_info,
 485                                                    "setting nodatacow");
 486                                 }
 487                         }
 488                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 489                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 490                         btrfs_set_opt(info->mount_opt, NODATACOW);
 491                         btrfs_set_opt(info->mount_opt, NODATASUM);
 492                         break;
 493                 case Opt_datacow:
 494                         btrfs_clear_and_info(info, NODATACOW,
 495                                              "setting datacow");
 496                         break;
 497                 case Opt_compress_force:
 498                 case Opt_compress_force_type:
 499                         compress_force = true;
 500                         /* Fallthrough */
 501                 case Opt_compress:
 502                 case Opt_compress_type:
 503                         saved_compress_type = btrfs_test_opt(info,
 504                                                              COMPRESS) ?
 505                                 info->compress_type : BTRFS_COMPRESS_NONE;
 506                         saved_compress_force =
 507                                 btrfs_test_opt(info, FORCE_COMPRESS);
 508                         if (token == Opt_compress ||
 509                             token == Opt_compress_force ||
 510                             strcmp(args[0].from, "zlib") == 0) {
 511                                 compress_type = "zlib";
 512                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 513                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 514                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 515                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 516                                 no_compress = 0;
 517                         } else if (strcmp(args[0].from, "lzo") == 0) {
 518                                 compress_type = "lzo";
 519                                 info->compress_type = BTRFS_COMPRESS_LZO;
 520                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 521                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 522                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 523                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 524                                 no_compress = 0;
 525                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 526                                 compress_type = "no";
 527                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 528                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 529                                 compress_force = false;
 530                                 no_compress++;
 531                         } else {
 532                                 ret = -EINVAL;
 533                                 goto out;
 534                         }
 535
 536                         if (compress_force) {
 537                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 538                         } else {
 539                                 /*
 540                                  * If we remount from compress-force=xxx to
 541                                  * compress=xxx, we need clear FORCE_COMPRESS
 542                                  * flag, otherwise, there is no way for users
 543                                  * to disable forcible compression separately.
 544                                  */
 545                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 546                         }
 547                         if ((btrfs_test_opt(info, COMPRESS) &&
 548                              (info->compress_type != saved_compress_type ||
 549                               compress_force != saved_compress_force)) ||
 550                             (!btrfs_test_opt(info, COMPRESS) &&
 551                              no_compress == 1)) {
 552                                 btrfs_info(root->fs_info,
 553                                            "%s %s compression",
 554                                            (compress_force) ? "force" : "use",
 555                                            compress_type);
 556                         }
 557                         compress_force = false;
 558                         break;
 559                 case Opt_ssd:
 560                         btrfs_set_and_info(info, SSD,
 561                                            "use ssd allocation scheme");
 562                         break;
 563                 case Opt_ssd_spread:
 564                         btrfs_set_and_info(info, SSD_SPREAD,
 565                                            "use spread ssd allocation scheme");
 566                         btrfs_set_opt(info->mount_opt, SSD);
 567                         break;
 568                 case Opt_nossd:
 569                         btrfs_set_and_info(info, NOSSD,
 570                                              "not using ssd allocation scheme");
 571                         btrfs_clear_opt(info->mount_opt, SSD);
 572                         break;
 573                 case Opt_barrier:
 574                         btrfs_clear_and_info(info, NOBARRIER,
 575                                              "turning on barriers");
 576                         break;
 577                 case Opt_nobarrier:
 578                         btrfs_set_and_info(info, NOBARRIER,
 579                                            "turning off barriers");
 580                         break;
 581                 case Opt_thread_pool:
 582                         ret = match_int(&args[0], &intarg);
 583                         if (ret) {
 584                                 goto out;
 585                         } else if (intarg > 0) {
 586                                 info->thread_pool_size = intarg;
 587                         } else {
 588                                 ret = -EINVAL;
 589                                 goto out;
 590                         }
 591                         break;
 592                 case Opt_max_inline:
 593                         num = match_strdup(&args[0]);
 594                         if (num) {
 595                                 info->max_inline = memparse(num, NULL);
 596                                 kfree(num);
 597
 598                                 if (info->max_inline) {
 599                                         info->max_inline = min_t(u64,
 600                                                 info->max_inline,
 601                                                 root->sectorsize);
 602                                 }
 603                                 btrfs_info(root->fs_info, "max_inline at %llu",
 604                                         info->max_inline);
 605                         } else {
 606                                 ret = -ENOMEM;
 607                                 goto out;
 608                         }
 609                         break;
 610                 case Opt_alloc_start:
 611                         num = match_strdup(&args[0]);
 612                         if (num) {
 613                                 mutex_lock(&info->chunk_mutex);
 614                                 info->alloc_start = memparse(num, NULL);
 615                                 mutex_unlock(&info->chunk_mutex);
 616                                 kfree(num);
 617                                 btrfs_info(root->fs_info,
 618                                            "allocations start at %llu",
 619                                            info->alloc_start);
 620                         } else {
 621                                 ret = -ENOMEM;
 622                                 goto out;
 623                         }
 624                         break;
 625                 case Opt_acl:
 626 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 627                         root->fs_info->sb->s_flags |= MS_POSIXACL;
 628                         break;
 629 #else
 630                         btrfs_err(root->fs_info,
 631                                 "support for ACL not compiled in!");
 632                         ret = -EINVAL;
 633                         goto out;
 634 #endif
 635                 case Opt_noacl:
 636                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 637                         break;
 638                 case Opt_notreelog:
 639                         btrfs_set_and_info(info, NOTREELOG,
 640                                            "disabling tree log");
 641                         break;
 642                 case Opt_treelog:
 643                         btrfs_clear_and_info(info, NOTREELOG,
 644                                              "enabling tree log");
 645                         break;
 646                 case Opt_norecovery:
 647                 case Opt_nologreplay:
 648                         btrfs_set_and_info(info, NOLOGREPLAY,
 649                                            "disabling log replay at mount time");
 650                         break;
 651                 case Opt_flushoncommit:
 652                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 653                                            "turning on flush-on-commit");
 654                         break;
 655                 case Opt_noflushoncommit:
 656                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 657                                              "turning off flush-on-commit");
 658                         break;
 659                 case Opt_ratio:
 660                         ret = match_int(&args[0], &intarg);
 661                         if (ret) {
 662                                 goto out;
 663                         } else if (intarg >= 0) {
 664                                 info->metadata_ratio = intarg;
 665                                 btrfs_info(root->fs_info, "metadata ratio %d",
 666                                        info->metadata_ratio);
 667                         } else {
 668                                 ret = -EINVAL;
 669                                 goto out;
 670                         }
 671                         break;
 672                 case Opt_discard:
 673                         btrfs_set_and_info(info, DISCARD,
 674                                            "turning on discard");
 675                         break;
 676                 case Opt_nodiscard:
 677                         btrfs_clear_and_info(info, DISCARD,
 678                                              "turning off discard");
 679                         break;
 680                 case Opt_space_cache:
 681                 case Opt_space_cache_version:
 682                         if (token == Opt_space_cache ||
 683                             strcmp(args[0].from, "v1") == 0) {
 684                                 btrfs_clear_opt(root->fs_info->mount_opt,
 685                                                 FREE_SPACE_TREE);
 686                                 btrfs_set_and_info(info, SPACE_CACHE,
 687                                                    "enabling disk space caching");
 688                         } else if (strcmp(args[0].from, "v2") == 0) {
 689                                 btrfs_clear_opt(root->fs_info->mount_opt,
 690                                                 SPACE_CACHE);
 691                                 btrfs_set_and_info(info,
 692                                                    FREE_SPACE_TREE,
 693                                                    "enabling free space tree");
 694                         } else {
 695                                 ret = -EINVAL;
 696                                 goto out;
 697                         }
 698                         break;
 699                 case Opt_rescan_uuid_tree:
 700                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 701                         break;
 702                 case Opt_no_space_cache:
 703                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 704                                 btrfs_clear_and_info(info,
 705                                                      SPACE_CACHE,
 706                                                      "disabling disk space caching");
 707                         }
 708                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 709                                 btrfs_clear_and_info(info,
 710                                                      FREE_SPACE_TREE,
 711                                                      "disabling free space tree");
 712                         }
 713                         break;
 714                 case Opt_inode_cache:
 715                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 716                                            "enabling inode map caching");
 717                         break;
 718                 case Opt_noinode_cache:
 719                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 720                                              "disabling inode map caching");
 721                         break;
 722                 case Opt_clear_cache:
 723                         btrfs_set_and_info(info, CLEAR_CACHE,
 724                                            "force clearing of disk cache");
 725                         break;
 726                 case Opt_user_subvol_rm_allowed:
 727                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 728                         break;
 729                 case Opt_enospc_debug:
 730                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 731                         break;
 732                 case Opt_noenospc_debug:
 733                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 734                         break;
 735                 case Opt_defrag:
 736                         btrfs_set_and_info(info, AUTO_DEFRAG,
 737                                            "enabling auto defrag");
 738                         break;
 739                 case Opt_nodefrag:
 740                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 741                                              "disabling auto defrag");
 742                         break;
 743                 case Opt_recovery:
 744                         btrfs_warn(root->fs_info,
 745                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 746                 case Opt_usebackuproot:
 747                         btrfs_info(root->fs_info,
 748                                    "trying to use backup root at mount time");
 749                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 750                         break;
 751                 case Opt_skip_balance:
 752                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 753                         break;
 754 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 755                 case Opt_check_integrity_including_extent_data:
 756                         btrfs_info(root->fs_info,
 757                                    "enabling check integrity including extent data");
 758                         btrfs_set_opt(info->mount_opt,
 759                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 760                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 761                         break;
 762                 case Opt_check_integrity:
 763                         btrfs_info(root->fs_info, "enabling check integrity");
 764                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 765                         break;
 766                 case Opt_check_integrity_print_mask:
 767                         ret = match_int(&args[0], &intarg);
 768                         if (ret) {
 769                                 goto out;
 770                         } else if (intarg >= 0) {
 771                                 info->check_integrity_print_mask = intarg;
 772                                 btrfs_info(root->fs_info,
 773                                            "check_integrity_print_mask 0x%x",
 774                                            info->check_integrity_print_mask);
 775                         } else {
 776                                 ret = -EINVAL;
 777                                 goto out;
 778                         }
 779                         break;
 780 #else
 781                 case Opt_check_integrity_including_extent_data:
 782                 case Opt_check_integrity:
 783                 case Opt_check_integrity_print_mask:
 784                         btrfs_err(root->fs_info,
 785                                 "support for check_integrity* not compiled in!");
 786                         ret = -EINVAL;
 787                         goto out;
 788 #endif
 789                 case Opt_fatal_errors:
 790                         if (strcmp(args[0].from, "panic") == 0)
 791                                 btrfs_set_opt(info->mount_opt,
 792                                               PANIC_ON_FATAL_ERROR);
 793                         else if (strcmp(args[0].from, "bug") == 0)
 794                                 btrfs_clear_opt(info->mount_opt,
 795                                               PANIC_ON_FATAL_ERROR);
 796                         else {
 797                                 ret = -EINVAL;
 798                                 goto out;
 799                         }
 800                         break;
 801                 case Opt_commit_interval:
 802                         intarg = 0;
 803                         ret = match_int(&args[0], &intarg);
 804                         if (ret < 0) {
 805                                 btrfs_err(root->fs_info,
 806                                           "invalid commit interval");
 807                                 ret = -EINVAL;
 808                                 goto out;
 809                         }
 810                         if (intarg > 0) {
 811                                 if (intarg > 300) {
 812                                         btrfs_warn(root->fs_info,
 813                                                 "excessive commit interval %d",
 814                                                 intarg);
 815                                 }
 816                                 info->commit_interval = intarg;
 817                         } else {
 818                                 btrfs_info(root->fs_info,
 819                                            "using default commit interval %ds",
 820                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 821                                 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 822                         }
 823                         break;
 824 #ifdef CONFIG_BTRFS_DEBUG
 825                 case Opt_fragment_all:
 826                         btrfs_info(root->fs_info, "fragmenting all space");
 827                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 828                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 829                         break;
 830                 case Opt_fragment_metadata:
 831                         btrfs_info(root->fs_info, "fragmenting metadata");
 832                         btrfs_set_opt(info->mount_opt,
 833                                       FRAGMENT_METADATA);
 834                         break;
 835                 case Opt_fragment_data:
 836                         btrfs_info(root->fs_info, "fragmenting data");
 837                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 838                         break;
 839 #endif
 840                 case Opt_err:
 841                         btrfs_info(root->fs_info,
 842                                    "unrecognized mount option '%s'", p);
 843                         ret = -EINVAL;
 844                         goto out;
 845                 default:
 846                         break;
 847                 }
 848         }
 849 check:
 850         /*
 851          * Extra check for current option against current flag
 852          */
 853         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
 854                 btrfs_err(root->fs_info,
 855                           "nologreplay must be used with ro mount option");
 856                 ret = -EINVAL;
 857         }
 858 out:
 859         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
 860             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 861             !btrfs_test_opt(info, CLEAR_CACHE)) {
 862                 btrfs_err(root->fs_info, "cannot disable free space tree");
 863                 ret = -EINVAL;
 864
 865         }
 866         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 867                 btrfs_info(root->fs_info, "disk space caching is enabled");
 868         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 869                 btrfs_info(root->fs_info, "using free space tree");
 870         kfree(orig);
 871         return ret;
 872 }
 873
 874 /*
 875  * Parse mount options that are required early in the mount process.
 876  *
 877  * All other options will be parsed on much later in the mount process and
 878  * only when we need to allocate a new super block.
 879  */
 880 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 881                 void *holder, char **subvol_name, u64 *subvol_objectid,
 882                 struct btrfs_fs_devices **fs_devices)
 883 {
 884         substring_t args[MAX_OPT_ARGS];
 885         char *device_name, *opts, *orig, *p;
 886         char *num = NULL;
 887         int error = 0;
 888
 889         if (!options)
 890                 return 0;
 891
 892         /*
 893          * strsep changes the string, duplicate it because parse_options
 894          * gets called twice
 895          */
 896         opts = kstrdup(options, GFP_KERNEL);
 897         if (!opts)
 898                 return -ENOMEM;
 899         orig = opts;
 900
 901         while ((p = strsep(&opts, ",")) != NULL) {
 902                 int token;
 903                 if (!*p)
 904                         continue;
 905
 906                 token = match_token(p, tokens, args);
 907                 switch (token) {
 908                 case Opt_subvol:
 909                         kfree(*subvol_name);
 910                         *subvol_name = match_strdup(&args[0]);
 911                         if (!*subvol_name) {
 912                                 error = -ENOMEM;
 913                                 goto out;
 914                         }
 915                         break;
 916                 case Opt_subvolid:
 917                         num = match_strdup(&args[0]);
 918                         if (num) {
 919                                 *subvol_objectid = memparse(num, NULL);
 920                                 kfree(num);
 921                                 /* we want the original fs_tree */
 922                                 if (!*subvol_objectid)
 923                                         *subvol_objectid =
 924                                                 BTRFS_FS_TREE_OBJECTID;
 925                         } else {
 926                                 error = -EINVAL;
 927                                 goto out;
 928                         }
 929                         break;
 930                 case Opt_subvolrootid:
 931                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
 932                         break;
 933                 case Opt_device:
 934                         device_name = match_strdup(&args[0]);
 935                         if (!device_name) {
 936                                 error = -ENOMEM;
 937                                 goto out;
 938                         }
 939                         error = btrfs_scan_one_device(device_name,
 940                                         flags, holder, fs_devices);
 941                         kfree(device_name);
 942                         if (error)
 943                                 goto out;
 944                         break;
 945                 default:
 946                         break;
 947                 }
 948         }
 949
 950 out:
 951         kfree(orig);
 952         return error;
 953 }
 954
 955 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 956                                            u64 subvol_objectid)
 957 {
 958         struct btrfs_root *root = fs_info->tree_root;
 959         struct btrfs_root *fs_root;
 960         struct btrfs_root_ref *root_ref;
 961         struct btrfs_inode_ref *inode_ref;
 962         struct btrfs_key key;
 963         struct btrfs_path *path = NULL;
 964         char *name = NULL, *ptr;
 965         u64 dirid;
 966         int len;
 967         int ret;
 968
 969         path = btrfs_alloc_path();
 970         if (!path) {
 971                 ret = -ENOMEM;
 972                 goto err;
 973         }
 974         path->leave_spinning = 1;
 975
 976         name = kmalloc(PATH_MAX, GFP_NOFS);
 977         if (!name) {
 978                 ret = -ENOMEM;
 979                 goto err;
 980         }
 981         ptr = name + PATH_MAX - 1;
 982         ptr[0] = '\0';
 983
 984         /*
 985          * Walk up the subvolume trees in the tree of tree roots by root
 986          * backrefs until we hit the top-level subvolume.
 987          */
 988         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 989                 key.objectid = subvol_objectid;
 990                 key.type = BTRFS_ROOT_BACKREF_KEY;
 991                 key.offset = (u64)-1;
 992
 993                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 994                 if (ret < 0) {
 995                         goto err;
 996                 } else if (ret > 0) {
 997                         ret = btrfs_previous_item(root, path, subvol_objectid,
 998                                                   BTRFS_ROOT_BACKREF_KEY);
 999                         if (ret < 0) {
1000                                 goto err;
1001                         } else if (ret > 0) {
1002                                 ret = -ENOENT;
1003                                 goto err;
1004                         }
1005                 }
1006
1007                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1008                 subvol_objectid = key.offset;
1009
1010                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1011                                           struct btrfs_root_ref);
1012                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1013                 ptr -= len + 1;
1014                 if (ptr < name) {
1015                         ret = -ENAMETOOLONG;
1016                         goto err;
1017                 }
1018                 read_extent_buffer(path->nodes[0], ptr + 1,
1019                                    (unsigned long)(root_ref + 1), len);
1020                 ptr[0] = '/';
1021                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1022                 btrfs_release_path(path);
1023
1024                 key.objectid = subvol_objectid;
1025                 key.type = BTRFS_ROOT_ITEM_KEY;
1026                 key.offset = (u64)-1;
1027                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1028                 if (IS_ERR(fs_root)) {
1029                         ret = PTR_ERR(fs_root);
1030                         goto err;
1031                 }
1032
1033                 /*
1034                  * Walk up the filesystem tree by inode refs until we hit the
1035                  * root directory.
1036                  */
1037                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1038                         key.objectid = dirid;
1039                         key.type = BTRFS_INODE_REF_KEY;
1040                         key.offset = (u64)-1;
1041
1042                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1043                         if (ret < 0) {
1044                                 goto err;
1045                         } else if (ret > 0) {
1046                                 ret = btrfs_previous_item(fs_root, path, dirid,
1047                                                           BTRFS_INODE_REF_KEY);
1048                                 if (ret < 0) {
1049                                         goto err;
1050                                 } else if (ret > 0) {
1051                                         ret = -ENOENT;
1052                                         goto err;
1053                                 }
1054                         }
1055
1056                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1057                         dirid = key.offset;
1058
1059                         inode_ref = btrfs_item_ptr(path->nodes[0],
1060                                                    path->slots[0],
1061                                                    struct btrfs_inode_ref);
1062                         len = btrfs_inode_ref_name_len(path->nodes[0],
1063                                                        inode_ref);
1064                         ptr -= len + 1;
1065                         if (ptr < name) {
1066                                 ret = -ENAMETOOLONG;
1067                                 goto err;
1068                         }
1069                         read_extent_buffer(path->nodes[0], ptr + 1,
1070                                            (unsigned long)(inode_ref + 1), len);
1071                         ptr[0] = '/';
1072                         btrfs_release_path(path);
1073                 }
1074         }
1075
1076         btrfs_free_path(path);
1077         if (ptr == name + PATH_MAX - 1) {
1078                 name[0] = '/';
1079                 name[1] = '\0';
1080         } else {
1081                 memmove(name, ptr, name + PATH_MAX - ptr);
1082         }
1083         return name;
1084
1085 err:
1086         btrfs_free_path(path);
1087         kfree(name);
1088         return ERR_PTR(ret);
1089 }
1090
1091 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1092 {
1093         struct btrfs_root *root = fs_info->tree_root;
1094         struct btrfs_dir_item *di;
1095         struct btrfs_path *path;
1096         struct btrfs_key location;
1097         u64 dir_id;
1098
1099         path = btrfs_alloc_path();
1100         if (!path)
1101                 return -ENOMEM;
1102         path->leave_spinning = 1;
1103
1104         /*
1105          * Find the "default" dir item which points to the root item that we
1106          * will mount by default if we haven't been given a specific subvolume
1107          * to mount.
1108          */
1109         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1110         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1111         if (IS_ERR(di)) {
1112                 btrfs_free_path(path);
1113                 return PTR_ERR(di);
1114         }
1115         if (!di) {
1116                 /*
1117                  * Ok the default dir item isn't there.  This is weird since
1118                  * it's always been there, but don't freak out, just try and
1119                  * mount the top-level subvolume.
1120                  */
1121                 btrfs_free_path(path);
1122                 *objectid = BTRFS_FS_TREE_OBJECTID;
1123                 return 0;
1124         }
1125
1126         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1127         btrfs_free_path(path);
1128         *objectid = location.objectid;
1129         return 0;
1130 }
1131
1132 static int btrfs_fill_super(struct super_block *sb,
1133                             struct btrfs_fs_devices *fs_devices,
1134                             void *data, int silent)
1135 {
1136         struct inode *inode;
1137         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1138         struct btrfs_key key;
1139         int err;
1140
1141         sb->s_maxbytes = MAX_LFS_FILESIZE;
1142         sb->s_magic = BTRFS_SUPER_MAGIC;
1143         sb->s_op = &btrfs_super_ops;
1144         sb->s_d_op = &btrfs_dentry_operations;
1145         sb->s_export_op = &btrfs_export_ops;
1146         sb->s_xattr = btrfs_xattr_handlers;
1147         sb->s_time_gran = 1;
1148 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1149         sb->s_flags |= MS_POSIXACL;
1150 #endif
1151         sb->s_flags |= MS_I_VERSION;
1152         sb->s_iflags |= SB_I_CGROUPWB;
1153         err = open_ctree(sb, fs_devices, (char *)data);
1154         if (err) {
1155                 btrfs_err(fs_info, "open_ctree failed");
1156                 return err;
1157         }
1158
1159         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1160         key.type = BTRFS_INODE_ITEM_KEY;
1161         key.offset = 0;
1162         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1163         if (IS_ERR(inode)) {
1164                 err = PTR_ERR(inode);
1165                 goto fail_close;
1166         }
1167
1168         sb->s_root = d_make_root(inode);
1169         if (!sb->s_root) {
1170                 err = -ENOMEM;
1171                 goto fail_close;
1172         }
1173
1174         save_mount_options(sb, data);
1175         cleancache_init_fs(sb);
1176         sb->s_flags |= MS_ACTIVE;
1177         return 0;
1178
1179 fail_close:
1180         close_ctree(fs_info->tree_root);
1181         return err;
1182 }
1183
1184 int btrfs_sync_fs(struct super_block *sb, int wait)
1185 {
1186         struct btrfs_trans_handle *trans;
1187         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1188         struct btrfs_root *root = fs_info->tree_root;
1189
1190         trace_btrfs_sync_fs(fs_info, wait);
1191
1192         if (!wait) {
1193                 filemap_flush(fs_info->btree_inode->i_mapping);
1194                 return 0;
1195         }
1196
1197         btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
1198
1199         trans = btrfs_attach_transaction_barrier(root);
1200         if (IS_ERR(trans)) {
1201                 /* no transaction, don't bother */
1202                 if (PTR_ERR(trans) == -ENOENT) {
1203                         /*
1204                          * Exit unless we have some pending changes
1205                          * that need to go through commit
1206                          */
1207                         if (fs_info->pending_changes == 0)
1208                                 return 0;
1209                         /*
1210                          * A non-blocking test if the fs is frozen. We must not
1211                          * start a new transaction here otherwise a deadlock
1212                          * happens. The pending operations are delayed to the
1213                          * next commit after thawing.
1214                          */
1215                         if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1216                                 __sb_end_write(sb, SB_FREEZE_WRITE);
1217                         else
1218                                 return 0;
1219                         trans = btrfs_start_transaction(root, 0);
1220                 }
1221                 if (IS_ERR(trans))
1222                         return PTR_ERR(trans);
1223         }
1224         return btrfs_commit_transaction(trans, root);
1225 }
1226
1227 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1228 {
1229         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1230         struct btrfs_root *root = info->tree_root;
1231         char *compress_type;
1232
1233         if (btrfs_test_opt(info, DEGRADED))
1234                 seq_puts(seq, ",degraded");
1235         if (btrfs_test_opt(info, NODATASUM))
1236                 seq_puts(seq, ",nodatasum");
1237         if (btrfs_test_opt(info, NODATACOW))
1238                 seq_puts(seq, ",nodatacow");
1239         if (btrfs_test_opt(info, NOBARRIER))
1240                 seq_puts(seq, ",nobarrier");
1241         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1242                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1243         if (info->alloc_start != 0)
1244                 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1245         if (info->thread_pool_size !=  min_t(unsigned long,
1246                                              num_online_cpus() + 2, 8))
1247                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1248         if (btrfs_test_opt(info, COMPRESS)) {
1249                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1250                         compress_type = "zlib";
1251                 else
1252                         compress_type = "lzo";
1253                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1254                         seq_printf(seq, ",compress-force=%s", compress_type);
1255                 else
1256                         seq_printf(seq, ",compress=%s", compress_type);
1257         }
1258         if (btrfs_test_opt(info, NOSSD))
1259                 seq_puts(seq, ",nossd");
1260         if (btrfs_test_opt(info, SSD_SPREAD))
1261                 seq_puts(seq, ",ssd_spread");
1262         else if (btrfs_test_opt(info, SSD))
1263                 seq_puts(seq, ",ssd");
1264         if (btrfs_test_opt(info, NOTREELOG))
1265                 seq_puts(seq, ",notreelog");
1266         if (btrfs_test_opt(info, NOLOGREPLAY))
1267                 seq_puts(seq, ",nologreplay");
1268         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1269                 seq_puts(seq, ",flushoncommit");
1270         if (btrfs_test_opt(info, DISCARD))
1271                 seq_puts(seq, ",discard");
1272         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1273                 seq_puts(seq, ",noacl");
1274         if (btrfs_test_opt(info, SPACE_CACHE))
1275                 seq_puts(seq, ",space_cache");
1276         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1277                 seq_puts(seq, ",space_cache=v2");
1278         else
1279                 seq_puts(seq, ",nospace_cache");
1280         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1281                 seq_puts(seq, ",rescan_uuid_tree");
1282         if (btrfs_test_opt(info, CLEAR_CACHE))
1283                 seq_puts(seq, ",clear_cache");
1284         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1285                 seq_puts(seq, ",user_subvol_rm_allowed");
1286         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1287                 seq_puts(seq, ",enospc_debug");
1288         if (btrfs_test_opt(info, AUTO_DEFRAG))
1289                 seq_puts(seq, ",autodefrag");
1290         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1291                 seq_puts(seq, ",inode_cache");
1292         if (btrfs_test_opt(info, SKIP_BALANCE))
1293                 seq_puts(seq, ",skip_balance");
1294 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1295         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1296                 seq_puts(seq, ",check_int_data");
1297         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1298                 seq_puts(seq, ",check_int");
1299         if (info->check_integrity_print_mask)
1300                 seq_printf(seq, ",check_int_print_mask=%d",
1301                                 info->check_integrity_print_mask);
1302 #endif
1303         if (info->metadata_ratio)
1304                 seq_printf(seq, ",metadata_ratio=%d",
1305                                 info->metadata_ratio);
1306         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1307                 seq_puts(seq, ",fatal_errors=panic");
1308         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1309                 seq_printf(seq, ",commit=%d", info->commit_interval);
1310 #ifdef CONFIG_BTRFS_DEBUG
1311         if (btrfs_test_opt(info, FRAGMENT_DATA))
1312                 seq_puts(seq, ",fragment=data");
1313         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1314                 seq_puts(seq, ",fragment=metadata");
1315 #endif
1316         seq_printf(seq, ",subvolid=%llu",
1317                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1318         seq_puts(seq, ",subvol=");
1319         seq_dentry(seq, dentry, " \t\n\\");
1320         return 0;
1321 }
1322
1323 static int btrfs_test_super(struct super_block *s, void *data)
1324 {
1325         struct btrfs_fs_info *p = data;
1326         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1327
1328         return fs_info->fs_devices == p->fs_devices;
1329 }
1330
1331 static int btrfs_set_super(struct super_block *s, void *data)
1332 {
1333         int err = set_anon_super(s, data);
1334         if (!err)
1335                 s->s_fs_info = data;
1336         return err;
1337 }
1338
1339 /*
1340  * subvolumes are identified by ino 256
1341  */
1342 static inline int is_subvolume_inode(struct inode *inode)
1343 {
1344         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1345                 return 1;
1346         return 0;
1347 }
1348
1349 /*
1350  * This will add subvolid=0 to the argument string while removing any subvol=
1351  * and subvolid= arguments to make sure we get the top-level root for path
1352  * walking to the subvol we want.
1353  */
1354 static char *setup_root_args(char *args)
1355 {
1356         char *buf, *dst, *sep;
1357
1358         if (!args)
1359                 return kstrdup("subvolid=0", GFP_NOFS);
1360
1361         /* The worst case is that we add ",subvolid=0" to the end. */
1362         buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1363         if (!buf)
1364                 return NULL;
1365
1366         while (1) {
1367                 sep = strchrnul(args, ',');
1368                 if (!strstarts(args, "subvol=") &&
1369                     !strstarts(args, "subvolid=")) {
1370                         memcpy(dst, args, sep - args);
1371                         dst += sep - args;
1372                         *dst++ = ',';
1373                 }
1374                 if (*sep)
1375                         args = sep + 1;
1376                 else
1377                         break;
1378         }
1379         strcpy(dst, "subvolid=0");
1380
1381         return buf;
1382 }
1383
1384 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1385                                    int flags, const char *device_name,
1386                                    char *data)
1387 {
1388         struct dentry *root;
1389         struct vfsmount *mnt = NULL;
1390         char *newargs;
1391         int ret;
1392
1393         newargs = setup_root_args(data);
1394         if (!newargs) {
1395                 root = ERR_PTR(-ENOMEM);
1396                 goto out;
1397         }
1398
1399         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1400         if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1401                 if (flags & MS_RDONLY) {
1402                         mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1403                                              device_name, newargs);
1404                 } else {
1405                         mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1406                                              device_name, newargs);
1407                         if (IS_ERR(mnt)) {
1408                                 root = ERR_CAST(mnt);
1409                                 mnt = NULL;
1410                                 goto out;
1411                         }
1412
1413                         down_write(&mnt->mnt_sb->s_umount);
1414                         ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1415                         up_write(&mnt->mnt_sb->s_umount);
1416                         if (ret < 0) {
1417                                 root = ERR_PTR(ret);
1418                                 goto out;
1419                         }
1420                 }
1421         }
1422         if (IS_ERR(mnt)) {
1423                 root = ERR_CAST(mnt);
1424                 mnt = NULL;
1425                 goto out;
1426         }
1427
1428         if (!subvol_name) {
1429                 if (!subvol_objectid) {
1430                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1431                                                           &subvol_objectid);
1432                         if (ret) {
1433                                 root = ERR_PTR(ret);
1434                                 goto out;
1435                         }
1436                 }
1437                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1438                                                             subvol_objectid);
1439                 if (IS_ERR(subvol_name)) {
1440                         root = ERR_CAST(subvol_name);
1441                         subvol_name = NULL;
1442                         goto out;
1443                 }
1444
1445         }
1446
1447         root = mount_subtree(mnt, subvol_name);
1448         /* mount_subtree() drops our reference on the vfsmount. */
1449         mnt = NULL;
1450
1451         if (!IS_ERR(root)) {
1452                 struct super_block *s = root->d_sb;
1453                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1454                 struct inode *root_inode = d_inode(root);
1455                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1456
1457                 ret = 0;
1458                 if (!is_subvolume_inode(root_inode)) {
1459                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1460                                subvol_name);
1461                         ret = -EINVAL;
1462                 }
1463                 if (subvol_objectid && root_objectid != subvol_objectid) {
1464                         /*
1465                          * This will also catch a race condition where a
1466                          * subvolume which was passed by ID is renamed and
1467                          * another subvolume is renamed over the old location.
1468                          */
1469                         btrfs_err(fs_info,
1470                                   "subvol '%s' does not match subvolid %llu",
1471                                   subvol_name, subvol_objectid);
1472                         ret = -EINVAL;
1473                 }
1474                 if (ret) {
1475                         dput(root);
1476                         root = ERR_PTR(ret);
1477                         deactivate_locked_super(s);
1478                 }
1479         }
1480
1481 out:
1482         mntput(mnt);
1483         kfree(newargs);
1484         kfree(subvol_name);
1485         return root;
1486 }
1487
1488 static int parse_security_options(char *orig_opts,
1489                                   struct security_mnt_opts *sec_opts)
1490 {
1491         char *secdata = NULL;
1492         int ret = 0;
1493
1494         secdata = alloc_secdata();
1495         if (!secdata)
1496                 return -ENOMEM;
1497         ret = security_sb_copy_data(orig_opts, secdata);
1498         if (ret) {
1499                 free_secdata(secdata);
1500                 return ret;
1501         }
1502         ret = security_sb_parse_opts_str(secdata, sec_opts);
1503         free_secdata(secdata);
1504         return ret;
1505 }
1506
1507 static int setup_security_options(struct btrfs_fs_info *fs_info,
1508                                   struct super_block *sb,
1509                                   struct security_mnt_opts *sec_opts)
1510 {
1511         int ret = 0;
1512
1513         /*
1514          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1515          * is valid.
1516          */
1517         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1518         if (ret)
1519                 return ret;
1520
1521 #ifdef CONFIG_SECURITY
1522         if (!fs_info->security_opts.num_mnt_opts) {
1523                 /* first time security setup, copy sec_opts to fs_info */
1524                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1525         } else {
1526                 /*
1527                  * Since SELinux (the only one supporting security_mnt_opts)
1528                  * does NOT support changing context during remount/mount of
1529                  * the same sb, this must be the same or part of the same
1530                  * security options, just free it.
1531                  */
1532                 security_free_mnt_opts(sec_opts);
1533         }
1534 #endif
1535         return ret;
1536 }
1537
1538 /*
1539  * Find a superblock for the given device / mount point.
1540  *
1541  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1542  *        for multiple device setup.  Make sure to keep it in sync.
1543  */
1544 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1545                 const char *device_name, void *data)
1546 {
1547         struct block_device *bdev = NULL;
1548         struct super_block *s;
1549         struct btrfs_fs_devices *fs_devices = NULL;
1550         struct btrfs_fs_info *fs_info = NULL;
1551         struct security_mnt_opts new_sec_opts;
1552         fmode_t mode = FMODE_READ;
1553         char *subvol_name = NULL;
1554         u64 subvol_objectid = 0;
1555         int error = 0;
1556
1557         if (!(flags & MS_RDONLY))
1558                 mode |= FMODE_WRITE;
1559
1560         error = btrfs_parse_early_options(data, mode, fs_type,
1561                                           &subvol_name, &subvol_objectid,
1562                                           &fs_devices);
1563         if (error) {
1564                 kfree(subvol_name);
1565                 return ERR_PTR(error);
1566         }
1567
1568         if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1569                 /* mount_subvol() will free subvol_name. */
1570                 return mount_subvol(subvol_name, subvol_objectid, flags,
1571                                     device_name, data);
1572         }
1573
1574         security_init_mnt_opts(&new_sec_opts);
1575         if (data) {
1576                 error = parse_security_options(data, &new_sec_opts);
1577                 if (error)
1578                         return ERR_PTR(error);
1579         }
1580
1581         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1582         if (error)
1583                 goto error_sec_opts;
1584
1585         /*
1586          * Setup a dummy root and fs_info for test/set super.  This is because
1587          * we don't actually fill this stuff out until open_ctree, but we need
1588          * it for searching for existing supers, so this lets us do that and
1589          * then open_ctree will properly initialize everything later.
1590          */
1591         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1592         if (!fs_info) {
1593                 error = -ENOMEM;
1594                 goto error_sec_opts;
1595         }
1596
1597         fs_info->fs_devices = fs_devices;
1598
1599         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1600         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1601         security_init_mnt_opts(&fs_info->security_opts);
1602         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1603                 error = -ENOMEM;
1604                 goto error_fs_info;
1605         }
1606
1607         error = btrfs_open_devices(fs_devices, mode, fs_type);
1608         if (error)
1609                 goto error_fs_info;
1610
1611         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1612                 error = -EACCES;
1613                 goto error_close_devices;
1614         }
1615
1616         bdev = fs_devices->latest_bdev;
1617         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1618                  fs_info);
1619         if (IS_ERR(s)) {
1620                 error = PTR_ERR(s);
1621                 goto error_close_devices;
1622         }
1623
1624         if (s->s_root) {
1625                 btrfs_close_devices(fs_devices);
1626                 free_fs_info(fs_info);
1627                 if ((flags ^ s->s_flags) & MS_RDONLY)
1628                         error = -EBUSY;
1629         } else {
1630                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1631                 btrfs_sb(s)->bdev_holder = fs_type;
1632                 error = btrfs_fill_super(s, fs_devices, data,
1633                                          flags & MS_SILENT ? 1 : 0);
1634         }
1635         if (error) {
1636                 deactivate_locked_super(s);
1637                 goto error_sec_opts;
1638         }
1639
1640         fs_info = btrfs_sb(s);
1641         error = setup_security_options(fs_info, s, &new_sec_opts);
1642         if (error) {
1643                 deactivate_locked_super(s);
1644                 goto error_sec_opts;
1645         }
1646
1647         return dget(s->s_root);
1648
1649 error_close_devices:
1650         btrfs_close_devices(fs_devices);
1651 error_fs_info:
1652         free_fs_info(fs_info);
1653 error_sec_opts:
1654         security_free_mnt_opts(&new_sec_opts);
1655         return ERR_PTR(error);
1656 }
1657
1658 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1659                                      int new_pool_size, int old_pool_size)
1660 {
1661         if (new_pool_size == old_pool_size)
1662                 return;
1663
1664         fs_info->thread_pool_size = new_pool_size;
1665
1666         btrfs_info(fs_info, "resize thread pool %d -> %d",
1667                old_pool_size, new_pool_size);
1668
1669         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1670         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1671         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1672         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1673         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1674         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1675         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1676                                 new_pool_size);
1677         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1678         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1679         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1680         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1681         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1682                                 new_pool_size);
1683 }
1684
1685 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1686 {
1687         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1688 }
1689
1690 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1691                                        unsigned long old_opts, int flags)
1692 {
1693         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1694             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1695              (flags & MS_RDONLY))) {
1696                 /* wait for any defraggers to finish */
1697                 wait_event(fs_info->transaction_wait,
1698                            (atomic_read(&fs_info->defrag_running) == 0));
1699                 if (flags & MS_RDONLY)
1700                         sync_filesystem(fs_info->sb);
1701         }
1702 }
1703
1704 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1705                                          unsigned long old_opts)
1706 {
1707         /*
1708          * We need to cleanup all defragable inodes if the autodefragment is
1709          * close or the filesystem is read only.
1710          */
1711         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1712             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1713              (fs_info->sb->s_flags & MS_RDONLY))) {
1714                 btrfs_cleanup_defrag_inodes(fs_info);
1715         }
1716
1717         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1718 }
1719
1720 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1721 {
1722         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1723         struct btrfs_root *root = fs_info->tree_root;
1724         unsigned old_flags = sb->s_flags;
1725         unsigned long old_opts = fs_info->mount_opt;
1726         unsigned long old_compress_type = fs_info->compress_type;
1727         u64 old_max_inline = fs_info->max_inline;
1728         u64 old_alloc_start = fs_info->alloc_start;
1729         int old_thread_pool_size = fs_info->thread_pool_size;
1730         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1731         int ret;
1732
1733         sync_filesystem(sb);
1734         btrfs_remount_prepare(fs_info);
1735
1736         if (data) {
1737                 struct security_mnt_opts new_sec_opts;
1738
1739                 security_init_mnt_opts(&new_sec_opts);
1740                 ret = parse_security_options(data, &new_sec_opts);
1741                 if (ret)
1742                         goto restore;
1743                 ret = setup_security_options(fs_info, sb,
1744                                              &new_sec_opts);
1745                 if (ret) {
1746                         security_free_mnt_opts(&new_sec_opts);
1747                         goto restore;
1748                 }
1749         }
1750
1751         ret = btrfs_parse_options(root, data, *flags);
1752         if (ret) {
1753                 ret = -EINVAL;
1754                 goto restore;
1755         }
1756
1757         btrfs_remount_begin(fs_info, old_opts, *flags);
1758         btrfs_resize_thread_pool(fs_info,
1759                 fs_info->thread_pool_size, old_thread_pool_size);
1760
1761         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1762                 goto out;
1763
1764         if (*flags & MS_RDONLY) {
1765                 /*
1766                  * this also happens on 'umount -rf' or on shutdown, when
1767                  * the filesystem is busy.
1768                  */
1769                 cancel_work_sync(&fs_info->async_reclaim_work);
1770
1771                 /* wait for the uuid_scan task to finish */
1772                 down(&fs_info->uuid_tree_rescan_sem);
1773                 /* avoid complains from lockdep et al. */
1774                 up(&fs_info->uuid_tree_rescan_sem);
1775
1776                 sb->s_flags |= MS_RDONLY;
1777
1778                 /*
1779                  * Setting MS_RDONLY will put the cleaner thread to
1780                  * sleep at the next loop if it's already active.
1781                  * If it's already asleep, we'll leave unused block
1782                  * groups on disk until we're mounted read-write again
1783                  * unless we clean them up here.
1784                  */
1785                 btrfs_delete_unused_bgs(fs_info);
1786
1787                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1788                 btrfs_scrub_cancel(fs_info);
1789                 btrfs_pause_balance(fs_info);
1790
1791                 ret = btrfs_commit_super(root);
1792                 if (ret)
1793                         goto restore;
1794         } else {
1795                 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1796                         btrfs_err(fs_info,
1797                                 "Remounting read-write after error is not allowed");
1798                         ret = -EINVAL;
1799                         goto restore;
1800                 }
1801                 if (fs_info->fs_devices->rw_devices == 0) {
1802                         ret = -EACCES;
1803                         goto restore;
1804                 }
1805
1806                 if (fs_info->fs_devices->missing_devices >
1807                      fs_info->num_tolerated_disk_barrier_failures &&
1808                     !(*flags & MS_RDONLY)) {
1809                         btrfs_warn(fs_info,
1810                                 "too many missing devices, writeable remount is not allowed");
1811                         ret = -EACCES;
1812                         goto restore;
1813                 }
1814
1815                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1816                         ret = -EINVAL;
1817                         goto restore;
1818                 }
1819
1820                 ret = btrfs_cleanup_fs_roots(fs_info);
1821                 if (ret)
1822                         goto restore;
1823
1824                 /* recover relocation */
1825                 mutex_lock(&fs_info->cleaner_mutex);
1826                 ret = btrfs_recover_relocation(root);
1827                 mutex_unlock(&fs_info->cleaner_mutex);
1828                 if (ret)
1829                         goto restore;
1830
1831                 ret = btrfs_resume_balance_async(fs_info);
1832                 if (ret)
1833                         goto restore;
1834
1835                 ret = btrfs_resume_dev_replace_async(fs_info);
1836                 if (ret) {
1837                         btrfs_warn(fs_info, "failed to resume dev_replace");
1838                         goto restore;
1839                 }
1840
1841                 if (!fs_info->uuid_root) {
1842                         btrfs_info(fs_info, "creating UUID tree");
1843                         ret = btrfs_create_uuid_tree(fs_info);
1844                         if (ret) {
1845                                 btrfs_warn(fs_info,
1846                                            "failed to create the UUID tree %d",
1847                                            ret);
1848                                 goto restore;
1849                         }
1850                 }
1851                 sb->s_flags &= ~MS_RDONLY;
1852
1853                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1854         }
1855 out:
1856         wake_up_process(fs_info->transaction_kthread);
1857         btrfs_remount_cleanup(fs_info, old_opts);
1858         return 0;
1859
1860 restore:
1861         /* We've hit an error - don't reset MS_RDONLY */
1862         if (sb->s_flags & MS_RDONLY)
1863                 old_flags |= MS_RDONLY;
1864         sb->s_flags = old_flags;
1865         fs_info->mount_opt = old_opts;
1866         fs_info->compress_type = old_compress_type;
1867         fs_info->max_inline = old_max_inline;
1868         mutex_lock(&fs_info->chunk_mutex);
1869         fs_info->alloc_start = old_alloc_start;
1870         mutex_unlock(&fs_info->chunk_mutex);
1871         btrfs_resize_thread_pool(fs_info,
1872                 old_thread_pool_size, fs_info->thread_pool_size);
1873         fs_info->metadata_ratio = old_metadata_ratio;
1874         btrfs_remount_cleanup(fs_info, old_opts);
1875         return ret;
1876 }
1877
1878 /* Used to sort the devices by max_avail(descending sort) */
1879 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1880                                        const void *dev_info2)
1881 {
1882         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1883             ((struct btrfs_device_info *)dev_info2)->max_avail)
1884                 return -1;
1885         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1886                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1887                 return 1;
1888         else
1889         return 0;
1890 }
1891
1892 /*
1893  * sort the devices by max_avail, in which max free extent size of each device
1894  * is stored.(Descending Sort)
1895  */
1896 static inline void btrfs_descending_sort_devices(
1897                                         struct btrfs_device_info *devices,
1898                                         size_t nr_devices)
1899 {
1900         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1901              btrfs_cmp_device_free_bytes, NULL);
1902 }
1903
1904 /*
1905  * The helper to calc the free space on the devices that can be used to store
1906  * file data.
1907  */
1908 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1909 {
1910         struct btrfs_fs_info *fs_info = root->fs_info;
1911         struct btrfs_device_info *devices_info;
1912         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1913         struct btrfs_device *device;
1914         u64 skip_space;
1915         u64 type;
1916         u64 avail_space;
1917         u64 used_space;
1918         u64 min_stripe_size;
1919         int min_stripes = 1, num_stripes = 1;
1920         int i = 0, nr_devices;
1921         int ret;
1922
1923         /*
1924          * We aren't under the device list lock, so this is racy-ish, but good
1925          * enough for our purposes.
1926          */
1927         nr_devices = fs_info->fs_devices->open_devices;
1928         if (!nr_devices) {
1929                 smp_mb();
1930                 nr_devices = fs_info->fs_devices->open_devices;
1931                 ASSERT(nr_devices);
1932                 if (!nr_devices) {
1933                         *free_bytes = 0;
1934                         return 0;
1935                 }
1936         }
1937
1938         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1939                                GFP_NOFS);
1940         if (!devices_info)
1941                 return -ENOMEM;
1942
1943         /* calc min stripe number for data space allocation */
1944         type = btrfs_get_alloc_profile(root, 1);
1945         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1946                 min_stripes = 2;
1947                 num_stripes = nr_devices;
1948         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1949                 min_stripes = 2;
1950                 num_stripes = 2;
1951         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1952                 min_stripes = 4;
1953                 num_stripes = 4;
1954         }
1955
1956         if (type & BTRFS_BLOCK_GROUP_DUP)
1957                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1958         else
1959                 min_stripe_size = BTRFS_STRIPE_LEN;
1960
1961         if (fs_info->alloc_start)
1962                 mutex_lock(&fs_devices->device_list_mutex);
1963         rcu_read_lock();
1964         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1965                 if (!device->in_fs_metadata || !device->bdev ||
1966                     device->is_tgtdev_for_dev_replace)
1967                         continue;
1968
1969                 if (i >= nr_devices)
1970                         break;
1971
1972                 avail_space = device->total_bytes - device->bytes_used;
1973
1974                 /* align with stripe_len */
1975                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1976                 avail_space *= BTRFS_STRIPE_LEN;
1977
1978                 /*
1979                  * In order to avoid overwriting the superblock on the drive,
1980                  * btrfs starts at an offset of at least 1MB when doing chunk
1981                  * allocation.
1982                  */
1983                 skip_space = SZ_1M;
1984
1985                 /* user can set the offset in fs_info->alloc_start. */
1986                 if (fs_info->alloc_start &&
1987                     fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1988                     device->total_bytes) {
1989                         rcu_read_unlock();
1990                         skip_space = max(fs_info->alloc_start, skip_space);
1991
1992                         /*
1993                          * btrfs can not use the free space in
1994                          * [0, skip_space - 1], we must subtract it from the
1995                          * total. In order to implement it, we account the used
1996                          * space in this range first.
1997                          */
1998                         ret = btrfs_account_dev_extents_size(device, 0,
1999                                                              skip_space - 1,
2000                                                              &used_space);
2001                         if (ret) {
2002                                 kfree(devices_info);
2003                                 mutex_unlock(&fs_devices->device_list_mutex);
2004                                 return ret;
2005                         }
2006
2007                         rcu_read_lock();
2008
2009                         /* calc the free space in [0, skip_space - 1] */
2010                         skip_space -= used_space;
2011                 }
2012
2013                 /*
2014                  * we can use the free space in [0, skip_space - 1], subtract
2015                  * it from the total.
2016                  */
2017                 if (avail_space && avail_space >= skip_space)
2018                         avail_space -= skip_space;
2019                 else
2020                         avail_space = 0;
2021
2022                 if (avail_space < min_stripe_size)
2023                         continue;
2024
2025                 devices_info[i].dev = device;
2026                 devices_info[i].max_avail = avail_space;
2027
2028                 i++;
2029         }
2030         rcu_read_unlock();
2031         if (fs_info->alloc_start)
2032                 mutex_unlock(&fs_devices->device_list_mutex);
2033
2034         nr_devices = i;
2035
2036         btrfs_descending_sort_devices(devices_info, nr_devices);
2037
2038         i = nr_devices - 1;
2039         avail_space = 0;
2040         while (nr_devices >= min_stripes) {
2041                 if (num_stripes > nr_devices)
2042                         num_stripes = nr_devices;
2043
2044                 if (devices_info[i].max_avail >= min_stripe_size) {
2045                         int j;
2046                         u64 alloc_size;
2047
2048                         avail_space += devices_info[i].max_avail * num_stripes;
2049                         alloc_size = devices_info[i].max_avail;
2050                         for (j = i + 1 - num_stripes; j <= i; j++)
2051                                 devices_info[j].max_avail -= alloc_size;
2052                 }
2053                 i--;
2054                 nr_devices--;
2055         }
2056
2057         kfree(devices_info);
2058         *free_bytes = avail_space;
2059         return 0;
2060 }
2061
2062 /*
2063  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2064  *
2065  * If there's a redundant raid level at DATA block groups, use the respective
2066  * multiplier to scale the sizes.
2067  *
2068  * Unused device space usage is based on simulating the chunk allocator
2069  * algorithm that respects the device sizes, order of allocations and the
2070  * 'alloc_start' value, this is a close approximation of the actual use but
2071  * there are other factors that may change the result (like a new metadata
2072  * chunk).
2073  *
2074  * If metadata is exhausted, f_bavail will be 0.
2075  */
2076 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2077 {
2078         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2079         struct btrfs_super_block *disk_super = fs_info->super_copy;
2080         struct list_head *head = &fs_info->space_info;
2081         struct btrfs_space_info *found;
2082         u64 total_used = 0;
2083         u64 total_free_data = 0;
2084         u64 total_free_meta = 0;
2085         int bits = dentry->d_sb->s_blocksize_bits;
2086         __be32 *fsid = (__be32 *)fs_info->fsid;
2087         unsigned factor = 1;
2088         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2089         int ret;
2090         u64 thresh = 0;
2091         int mixed = 0;
2092
2093         /*
2094          * holding chunk_mutex to avoid allocating new chunks, holding
2095          * device_list_mutex to avoid the device being removed
2096          */
2097         rcu_read_lock();
2098         list_for_each_entry_rcu(found, head, list) {
2099                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2100                         int i;
2101
2102                         total_free_data += found->disk_total - found->disk_used;
2103                         total_free_data -=
2104                                 btrfs_account_ro_block_groups_free_space(found);
2105
2106                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2107                                 if (!list_empty(&found->block_groups[i])) {
2108                                         switch (i) {
2109                                         case BTRFS_RAID_DUP:
2110                                         case BTRFS_RAID_RAID1:
2111                                         case BTRFS_RAID_RAID10:
2112                                                 factor = 2;
2113                                         }
2114                                 }
2115                         }
2116                 }
2117
2118                 /*
2119                  * Metadata in mixed block goup profiles are accounted in data
2120                  */
2121                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2122                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2123                                 mixed = 1;
2124                         else
2125                                 total_free_meta += found->disk_total -
2126                                         found->disk_used;
2127                 }
2128
2129                 total_used += found->disk_used;
2130         }
2131
2132         rcu_read_unlock();
2133
2134         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2135         buf->f_blocks >>= bits;
2136         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2137
2138         /* Account global block reserve as used, it's in logical size already */
2139         spin_lock(&block_rsv->lock);
2140         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2141         if (buf->f_bfree >= block_rsv->size >> bits)
2142                 buf->f_bfree -= block_rsv->size >> bits;
2143         else
2144                 buf->f_bfree = 0;
2145         spin_unlock(&block_rsv->lock);
2146
2147         buf->f_bavail = div_u64(total_free_data, factor);
2148         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2149         if (ret)
2150                 return ret;
2151         buf->f_bavail += div_u64(total_free_data, factor);
2152         buf->f_bavail = buf->f_bavail >> bits;
2153
2154         /*
2155          * We calculate the remaining metadata space minus global reserve. If
2156          * this is (supposedly) smaller than zero, there's no space. But this
2157          * does not hold in practice, the exhausted state happens where's still
2158          * some positive delta. So we apply some guesswork and compare the
2159          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2160          *
2161          * We probably cannot calculate the exact threshold value because this
2162          * depends on the internal reservations requested by various
2163          * operations, so some operations that consume a few metadata will
2164          * succeed even if the Avail is zero. But this is better than the other
2165          * way around.
2166          */
2167         thresh = 4 * 1024 * 1024;
2168
2169         if (!mixed && total_free_meta - thresh < block_rsv->size)
2170                 buf->f_bavail = 0;
2171
2172         buf->f_type = BTRFS_SUPER_MAGIC;
2173         buf->f_bsize = dentry->d_sb->s_blocksize;
2174         buf->f_namelen = BTRFS_NAME_LEN;
2175
2176         /* We treat it as constant endianness (it doesn't matter _which_)
2177            because we want the fsid to come out the same whether mounted
2178            on a big-endian or little-endian host */
2179         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2180         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2181         /* Mask in the root object ID too, to disambiguate subvols */
2182         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2183         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2184
2185         return 0;
2186 }
2187
2188 static void btrfs_kill_super(struct super_block *sb)
2189 {
2190         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2191         kill_anon_super(sb);
2192         free_fs_info(fs_info);
2193 }
2194
2195 static struct file_system_type btrfs_fs_type = {
2196         .owner          = THIS_MODULE,
2197         .name           = "btrfs",
2198         .mount          = btrfs_mount,
2199         .kill_sb        = btrfs_kill_super,
2200         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2201 };
2202 MODULE_ALIAS_FS("btrfs");
2203
2204 static int btrfs_control_open(struct inode *inode, struct file *file)
2205 {
2206         /*
2207          * The control file's private_data is used to hold the
2208          * transaction when it is started and is used to keep
2209          * track of whether a transaction is already in progress.
2210          */
2211         file->private_data = NULL;
2212         return 0;
2213 }
2214
2215 /*
2216  * used by btrfsctl to scan devices when no FS is mounted
2217  */
2218 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2219                                 unsigned long arg)
2220 {
2221         struct btrfs_ioctl_vol_args *vol;
2222         struct btrfs_fs_devices *fs_devices;
2223         int ret = -ENOTTY;
2224
2225         if (!capable(CAP_SYS_ADMIN))
2226                 return -EPERM;
2227
2228         vol = memdup_user((void __user *)arg, sizeof(*vol));
2229         if (IS_ERR(vol))
2230                 return PTR_ERR(vol);
2231
2232         switch (cmd) {
2233         case BTRFS_IOC_SCAN_DEV:
2234                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2235                                             &btrfs_fs_type, &fs_devices);
2236                 break;
2237         case BTRFS_IOC_DEVICES_READY:
2238                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2239                                             &btrfs_fs_type, &fs_devices);
2240                 if (ret)
2241                         break;
2242                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2243                 break;
2244         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2245                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2246                 break;
2247         }
2248
2249         kfree(vol);
2250         return ret;
2251 }
2252
2253 static int btrfs_freeze(struct super_block *sb)
2254 {
2255         struct btrfs_trans_handle *trans;
2256         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2257
2258         root->fs_info->fs_frozen = 1;
2259         /*
2260          * We don't need a barrier here, we'll wait for any transaction that
2261          * could be in progress on other threads (and do delayed iputs that
2262          * we want to avoid on a frozen filesystem), or do the commit
2263          * ourselves.
2264          */
2265         trans = btrfs_attach_transaction_barrier(root);
2266         if (IS_ERR(trans)) {
2267                 /* no transaction, don't bother */
2268                 if (PTR_ERR(trans) == -ENOENT)
2269                         return 0;
2270                 return PTR_ERR(trans);
2271         }
2272         return btrfs_commit_transaction(trans, root);
2273 }
2274
2275 static int btrfs_unfreeze(struct super_block *sb)
2276 {
2277         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2278
2279         root->fs_info->fs_frozen = 0;
2280         return 0;
2281 }
2282
2283 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2284 {
2285         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2286         struct btrfs_fs_devices *cur_devices;
2287         struct btrfs_device *dev, *first_dev = NULL;
2288         struct list_head *head;
2289         struct rcu_string *name;
2290
2291         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2292         cur_devices = fs_info->fs_devices;
2293         while (cur_devices) {
2294                 head = &cur_devices->devices;
2295                 list_for_each_entry(dev, head, dev_list) {
2296                         if (dev->missing)
2297                                 continue;
2298                         if (!dev->name)
2299                                 continue;
2300                         if (!first_dev || dev->devid < first_dev->devid)
2301                                 first_dev = dev;
2302                 }
2303                 cur_devices = cur_devices->seed;
2304         }
2305
2306         if (first_dev) {
2307                 rcu_read_lock();
2308                 name = rcu_dereference(first_dev->name);
2309                 seq_escape(m, name->str, " \t\n\\");
2310                 rcu_read_unlock();
2311         } else {
2312                 WARN_ON(1);
2313         }
2314         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2315         return 0;
2316 }
2317
2318 static const struct super_operations btrfs_super_ops = {
2319         .drop_inode     = btrfs_drop_inode,
2320         .evict_inode    = btrfs_evict_inode,
2321         .put_super      = btrfs_put_super,
2322         .sync_fs        = btrfs_sync_fs,
2323         .show_options   = btrfs_show_options,
2324         .show_devname   = btrfs_show_devname,
2325         .write_inode    = btrfs_write_inode,
2326         .alloc_inode    = btrfs_alloc_inode,
2327         .destroy_inode  = btrfs_destroy_inode,
2328         .statfs         = btrfs_statfs,
2329         .remount_fs     = btrfs_remount,
2330         .freeze_fs      = btrfs_freeze,
2331         .unfreeze_fs    = btrfs_unfreeze,
2332 };
2333
2334 static const struct file_operations btrfs_ctl_fops = {
2335         .open = btrfs_control_open,
2336         .unlocked_ioctl  = btrfs_control_ioctl,
2337         .compat_ioctl = btrfs_control_ioctl,
2338         .owner   = THIS_MODULE,
2339         .llseek = noop_llseek,
2340 };
2341
2342 static struct miscdevice btrfs_misc = {
2343         .minor          = BTRFS_MINOR,
2344         .name           = "btrfs-control",
2345         .fops           = &btrfs_ctl_fops
2346 };
2347
2348 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2349 MODULE_ALIAS("devname:btrfs-control");
2350
2351 static int btrfs_interface_init(void)
2352 {
2353         return misc_register(&btrfs_misc);
2354 }
2355
2356 static void btrfs_interface_exit(void)
2357 {
2358         misc_deregister(&btrfs_misc);
2359 }
2360
2361 static void btrfs_print_mod_info(void)
2362 {
2363         pr_info("Btrfs loaded, crc32c=%s"
2364 #ifdef CONFIG_BTRFS_DEBUG
2365                         ", debug=on"
2366 #endif
2367 #ifdef CONFIG_BTRFS_ASSERT
2368                         ", assert=on"
2369 #endif
2370 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2371                         ", integrity-checker=on"
2372 #endif
2373                         "\n",
2374                         btrfs_crc32c_impl());
2375 }
2376
2377 static int __init init_btrfs_fs(void)
2378 {
2379         int err;
2380
2381         err = btrfs_hash_init();
2382         if (err)
2383                 return err;
2384
2385         btrfs_props_init();
2386
2387         err = btrfs_init_sysfs();
2388         if (err)
2389                 goto free_hash;
2390
2391         btrfs_init_compress();
2392
2393         err = btrfs_init_cachep();
2394         if (err)
2395                 goto free_compress;
2396
2397         err = extent_io_init();
2398         if (err)
2399                 goto free_cachep;
2400
2401         err = extent_map_init();
2402         if (err)
2403                 goto free_extent_io;
2404
2405         err = ordered_data_init();
2406         if (err)
2407                 goto free_extent_map;
2408
2409         err = btrfs_delayed_inode_init();
2410         if (err)
2411                 goto free_ordered_data;
2412
2413         err = btrfs_auto_defrag_init();
2414         if (err)
2415                 goto free_delayed_inode;
2416
2417         err = btrfs_delayed_ref_init();
2418         if (err)
2419                 goto free_auto_defrag;
2420
2421         err = btrfs_prelim_ref_init();
2422         if (err)
2423                 goto free_delayed_ref;
2424
2425         err = btrfs_end_io_wq_init();
2426         if (err)
2427                 goto free_prelim_ref;
2428
2429         err = btrfs_interface_init();
2430         if (err)
2431                 goto free_end_io_wq;
2432
2433         btrfs_init_lockdep();
2434
2435         btrfs_print_mod_info();
2436
2437         err = btrfs_run_sanity_tests();
2438         if (err)
2439                 goto unregister_ioctl;
2440
2441         err = register_filesystem(&btrfs_fs_type);
2442         if (err)
2443                 goto unregister_ioctl;
2444
2445         return 0;
2446
2447 unregister_ioctl:
2448         btrfs_interface_exit();
2449 free_end_io_wq:
2450         btrfs_end_io_wq_exit();
2451 free_prelim_ref:
2452         btrfs_prelim_ref_exit();
2453 free_delayed_ref:
2454         btrfs_delayed_ref_exit();
2455 free_auto_defrag:
2456         btrfs_auto_defrag_exit();
2457 free_delayed_inode:
2458         btrfs_delayed_inode_exit();
2459 free_ordered_data:
2460         ordered_data_exit();
2461 free_extent_map:
2462         extent_map_exit();
2463 free_extent_io:
2464         extent_io_exit();
2465 free_cachep:
2466         btrfs_destroy_cachep();
2467 free_compress:
2468         btrfs_exit_compress();
2469         btrfs_exit_sysfs();
2470 free_hash:
2471         btrfs_hash_exit();
2472         return err;
2473 }
2474
2475 static void __exit exit_btrfs_fs(void)
2476 {
2477         btrfs_destroy_cachep();
2478         btrfs_delayed_ref_exit();
2479         btrfs_auto_defrag_exit();
2480         btrfs_delayed_inode_exit();
2481         btrfs_prelim_ref_exit();
2482         ordered_data_exit();
2483         extent_map_exit();
2484         extent_io_exit();
2485         btrfs_interface_exit();
2486         btrfs_end_io_wq_exit();
2487         unregister_filesystem(&btrfs_fs_type);
2488         btrfs_exit_sysfs();
2489         btrfs_cleanup_fs_uuids();
2490         btrfs_exit_compress();
2491         btrfs_hash_exit();
2492 }
2493
2494 late_initcall(init_btrfs_fs);
2495 module_exit(exit_btrfs_fs)
2496
2497 MODULE_LICENSE("GPL");