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/crc32c.h>
  45 #include <linux/btrfs.h>
  46 #include "delayed-inode.h"
  47 #include "ctree.h"
  48 #include "disk-io.h"
  49 #include "transaction.h"
  50 #include "btrfs_inode.h"
  51 #include "print-tree.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
  69 /*
  70  * Types for mounting the default subvolume and a subvolume explicitly
  71  * requested by subvol=/path. That way the callchain is straightforward and we
  72  * don't have to play tricks with the mount options and recursive calls to
  73  * btrfs_mount.
  74  *
  75  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
  76  */
  77 static struct file_system_type btrfs_fs_type;
  78 static struct file_system_type btrfs_root_fs_type;
  79
  80 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  81
  82 const char *btrfs_decode_error(int errno)
  83 {
  84         char *errstr = "unknown";
  85
  86         switch (errno) {
  87         case -EIO:
  88                 errstr = "IO failure";
  89                 break;
  90         case -ENOMEM:
  91                 errstr = "Out of memory";
  92                 break;
  93         case -EROFS:
  94                 errstr = "Readonly filesystem";
  95                 break;
  96         case -EEXIST:
  97                 errstr = "Object already exists";
  98                 break;
  99         case -ENOSPC:
 100                 errstr = "No space left";
 101                 break;
 102         case -ENOENT:
 103                 errstr = "No such entry";
 104                 break;
 105         }
 106
 107         return errstr;
 108 }
 109
 110 /*
 111  * __btrfs_handle_fs_error decodes expected errors from the caller and
 112  * invokes the approciate error response.
 113  */
 114 __cold
 115 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 116                        unsigned int line, int errno, const char *fmt, ...)
 117 {
 118         struct super_block *sb = fs_info->sb;
 119 #ifdef CONFIG_PRINTK
 120         const char *errstr;
 121 #endif
 122
 123         /*
 124          * Special case: if the error is EROFS, and we're already
 125          * under SB_RDONLY, then it is safe here.
 126          */
 127         if (errno == -EROFS && sb_rdonly(sb))
 128                 return;
 129
 130 #ifdef CONFIG_PRINTK
 131         errstr = btrfs_decode_error(errno);
 132         if (fmt) {
 133                 struct va_format vaf;
 134                 va_list args;
 135
 136                 va_start(args, fmt);
 137                 vaf.fmt = fmt;
 138                 vaf.va = &args;
 139
 140                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 141                         sb->s_id, function, line, errno, errstr, &vaf);
 142                 va_end(args);
 143         } else {
 144                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 145                         sb->s_id, function, line, errno, errstr);
 146         }
 147 #endif
 148
 149         /*
 150          * Today we only save the error info to memory.  Long term we'll
 151          * also send it down to the disk
 152          */
 153         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 154
 155         /* Don't go through full error handling during mount */
 156         if (!(sb->s_flags & SB_BORN))
 157                 return;
 158
 159         if (sb_rdonly(sb))
 160                 return;
 161
 162         /* btrfs handle error by forcing the filesystem readonly */
 163         sb->s_flags |= SB_RDONLY;
 164         btrfs_info(fs_info, "forced readonly");
 165         /*
 166          * Note that a running device replace operation is not canceled here
 167          * although there is no way to update the progress. It would add the
 168          * risk of a deadlock, therefore the canceling is omitted. The only
 169          * penalty is that some I/O remains active until the procedure
 170          * completes. The next time when the filesystem is mounted writeable
 171          * again, the device replace operation continues.
 172          */
 173 }
 174
 175 #ifdef CONFIG_PRINTK
 176 static const char * const logtypes[] = {
 177         "emergency",
 178         "alert",
 179         "critical",
 180         "error",
 181         "warning",
 182         "notice",
 183         "info",
 184         "debug",
 185 };
 186
 187
 188 /*
 189  * Use one ratelimit state per log level so that a flood of less important
 190  * messages doesn't cause more important ones to be dropped.
 191  */
 192 static struct ratelimit_state printk_limits[] = {
 193         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 194         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 195         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 196         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 197         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 198         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 199         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 200         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 201 };
 202
 203 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 204 {
 205         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
 206         struct va_format vaf;
 207         va_list args;
 208         int kern_level;
 209         const char *type = logtypes[4];
 210         struct ratelimit_state *ratelimit = &printk_limits[4];
 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         vaf.fmt = fmt;
 227         vaf.va = &args;
 228
 229         if (__ratelimit(ratelimit))
 230                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type,
 231                         fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);
 232
 233         va_end(args);
 234 }
 235 #endif
 236
 237 /*
 238  * We only mark the transaction aborted and then set the file system read-only.
 239  * This will prevent new transactions from starting or trying to join this
 240  * one.
 241  *
 242  * This means that error recovery at the call site is limited to freeing
 243  * any local memory allocations and passing the error code up without
 244  * further cleanup. The transaction should complete as it normally would
 245  * in the call path but will return -EIO.
 246  *
 247  * We'll complete the cleanup in btrfs_end_transaction and
 248  * btrfs_commit_transaction.
 249  */
 250 __cold
 251 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 252                                const char *function,
 253                                unsigned int line, int errno)
 254 {
 255         struct btrfs_fs_info *fs_info = trans->fs_info;
 256
 257         trans->aborted = errno;
 258         /* Nothing used. The other threads that have joined this
 259          * transaction may be able to continue. */
 260         if (!trans->dirty && list_empty(&trans->new_bgs)) {
 261                 const char *errstr;
 262
 263                 errstr = btrfs_decode_error(errno);
 264                 btrfs_warn(fs_info,
 265                            "%s:%d: Aborting unused transaction(%s).",
 266                            function, line, errstr);
 267                 return;
 268         }
 269         WRITE_ONCE(trans->transaction->aborted, errno);
 270         /* Wake up anybody who may be waiting on this transaction */
 271         wake_up(&fs_info->transaction_wait);
 272         wake_up(&fs_info->transaction_blocked_wait);
 273         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 274 }
 275 /*
 276  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 277  * issues an alert, and either panics or BUGs, depending on mount options.
 278  */
 279 __cold
 280 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 281                    unsigned int line, int errno, const char *fmt, ...)
 282 {
 283         char *s_id = "<unknown>";
 284         const char *errstr;
 285         struct va_format vaf = { .fmt = fmt };
 286         va_list args;
 287
 288         if (fs_info)
 289                 s_id = fs_info->sb->s_id;
 290
 291         va_start(args, fmt);
 292         vaf.va = &args;
 293
 294         errstr = btrfs_decode_error(errno);
 295         if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
 296                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 297                         s_id, function, line, &vaf, errno, errstr);
 298
 299         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 300                    function, line, &vaf, errno, errstr);
 301         va_end(args);
 302         /* Caller calls BUG() */
 303 }
 304
 305 static void btrfs_put_super(struct super_block *sb)
 306 {
 307         close_ctree(btrfs_sb(sb));
 308 }
 309
 310 enum {
 311         Opt_acl, Opt_noacl,
 312         Opt_clear_cache,
 313         Opt_commit_interval,
 314         Opt_compress,
 315         Opt_compress_force,
 316         Opt_compress_force_type,
 317         Opt_compress_type,
 318         Opt_degraded,
 319         Opt_device,
 320         Opt_fatal_errors,
 321         Opt_flushoncommit, Opt_noflushoncommit,
 322         Opt_inode_cache, Opt_noinode_cache,
 323         Opt_max_inline,
 324         Opt_barrier, Opt_nobarrier,
 325         Opt_datacow, Opt_nodatacow,
 326         Opt_datasum, Opt_nodatasum,
 327         Opt_defrag, Opt_nodefrag,
 328         Opt_discard, Opt_nodiscard,
 329         Opt_nologreplay,
 330         Opt_norecovery,
 331         Opt_ratio,
 332         Opt_rescan_uuid_tree,
 333         Opt_skip_balance,
 334         Opt_space_cache, Opt_no_space_cache,
 335         Opt_space_cache_version,
 336         Opt_ssd, Opt_nossd,
 337         Opt_ssd_spread, Opt_nossd_spread,
 338         Opt_subvol,
 339         Opt_subvolid,
 340         Opt_thread_pool,
 341         Opt_treelog, Opt_notreelog,
 342         Opt_usebackuproot,
 343         Opt_user_subvol_rm_allowed,
 344
 345         /* Deprecated options */
 346         Opt_alloc_start,
 347         Opt_recovery,
 348         Opt_subvolrootid,
 349
 350         /* Debugging options */
 351         Opt_check_integrity,
 352         Opt_check_integrity_including_extent_data,
 353         Opt_check_integrity_print_mask,
 354         Opt_enospc_debug, Opt_noenospc_debug,
 355 #ifdef CONFIG_BTRFS_DEBUG
 356         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 357 #endif
 358 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 359         Opt_ref_verify,
 360 #endif
 361         Opt_err,
 362 };
 363
 364 static const match_table_t tokens = {
 365         {Opt_acl, "acl"},
 366         {Opt_noacl, "noacl"},
 367         {Opt_clear_cache, "clear_cache"},
 368         {Opt_commit_interval, "commit=%u"},
 369         {Opt_compress, "compress"},
 370         {Opt_compress_type, "compress=%s"},
 371         {Opt_compress_force, "compress-force"},
 372         {Opt_compress_force_type, "compress-force=%s"},
 373         {Opt_degraded, "degraded"},
 374         {Opt_device, "device=%s"},
 375         {Opt_fatal_errors, "fatal_errors=%s"},
 376         {Opt_flushoncommit, "flushoncommit"},
 377         {Opt_noflushoncommit, "noflushoncommit"},
 378         {Opt_inode_cache, "inode_cache"},
 379         {Opt_noinode_cache, "noinode_cache"},
 380         {Opt_max_inline, "max_inline=%s"},
 381         {Opt_barrier, "barrier"},
 382         {Opt_nobarrier, "nobarrier"},
 383         {Opt_datacow, "datacow"},
 384         {Opt_nodatacow, "nodatacow"},
 385         {Opt_datasum, "datasum"},
 386         {Opt_nodatasum, "nodatasum"},
 387         {Opt_defrag, "autodefrag"},
 388         {Opt_nodefrag, "noautodefrag"},
 389         {Opt_discard, "discard"},
 390         {Opt_nodiscard, "nodiscard"},
 391         {Opt_nologreplay, "nologreplay"},
 392         {Opt_norecovery, "norecovery"},
 393         {Opt_ratio, "metadata_ratio=%u"},
 394         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 395         {Opt_skip_balance, "skip_balance"},
 396         {Opt_space_cache, "space_cache"},
 397         {Opt_no_space_cache, "nospace_cache"},
 398         {Opt_space_cache_version, "space_cache=%s"},
 399         {Opt_ssd, "ssd"},
 400         {Opt_nossd, "nossd"},
 401         {Opt_ssd_spread, "ssd_spread"},
 402         {Opt_nossd_spread, "nossd_spread"},
 403         {Opt_subvol, "subvol=%s"},
 404         {Opt_subvolid, "subvolid=%s"},
 405         {Opt_thread_pool, "thread_pool=%u"},
 406         {Opt_treelog, "treelog"},
 407         {Opt_notreelog, "notreelog"},
 408         {Opt_usebackuproot, "usebackuproot"},
 409         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 410
 411         /* Deprecated options */
 412         {Opt_alloc_start, "alloc_start=%s"},
 413         {Opt_recovery, "recovery"},
 414         {Opt_subvolrootid, "subvolrootid=%d"},
 415
 416         /* Debugging options */
 417         {Opt_check_integrity, "check_int"},
 418         {Opt_check_integrity_including_extent_data, "check_int_data"},
 419         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
 420         {Opt_enospc_debug, "enospc_debug"},
 421         {Opt_noenospc_debug, "noenospc_debug"},
 422 #ifdef CONFIG_BTRFS_DEBUG
 423         {Opt_fragment_data, "fragment=data"},
 424         {Opt_fragment_metadata, "fragment=metadata"},
 425         {Opt_fragment_all, "fragment=all"},
 426 #endif
 427 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 428         {Opt_ref_verify, "ref_verify"},
 429 #endif
 430         {Opt_err, NULL},
 431 };
 432
 433 /*
 434  * Regular mount options parser.  Everything that is needed only when
 435  * reading in a new superblock is parsed here.
 436  * XXX JDM: This needs to be cleaned up for remount.
 437  */
 438 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 439                         unsigned long new_flags)
 440 {
 441         substring_t args[MAX_OPT_ARGS];
 442         char *p, *num;
 443         u64 cache_gen;
 444         int intarg;
 445         int ret = 0;
 446         char *compress_type;
 447         bool compress_force = false;
 448         enum btrfs_compression_type saved_compress_type;
 449         bool saved_compress_force;
 450         int no_compress = 0;
 451
 452         cache_gen = btrfs_super_cache_generation(info->super_copy);
 453         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 454                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 455         else if (cache_gen)
 456                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 457
 458         /*
 459          * Even the options are empty, we still need to do extra check
 460          * against new flags
 461          */
 462         if (!options)
 463                 goto check;
 464
 465         while ((p = strsep(&options, ",")) != NULL) {
 466                 int token;
 467                 if (!*p)
 468                         continue;
 469
 470                 token = match_token(p, tokens, args);
 471                 switch (token) {
 472                 case Opt_degraded:
 473                         btrfs_info(info, "allowing degraded mounts");
 474                         btrfs_set_opt(info->mount_opt, DEGRADED);
 475                         break;
 476                 case Opt_subvol:
 477                 case Opt_subvolid:
 478                 case Opt_subvolrootid:
 479                 case Opt_device:
 480                         /*
 481                          * These are parsed by btrfs_parse_subvol_options
 482                          * and btrfs_parse_early_options
 483                          * and can be happily ignored here.
 484                          */
 485                         break;
 486                 case Opt_nodatasum:
 487                         btrfs_set_and_info(info, NODATASUM,
 488                                            "setting nodatasum");
 489                         break;
 490                 case Opt_datasum:
 491                         if (btrfs_test_opt(info, NODATASUM)) {
 492                                 if (btrfs_test_opt(info, NODATACOW))
 493                                         btrfs_info(info,
 494                                                    "setting datasum, datacow enabled");
 495                                 else
 496                                         btrfs_info(info, "setting datasum");
 497                         }
 498                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 499                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 500                         break;
 501                 case Opt_nodatacow:
 502                         if (!btrfs_test_opt(info, NODATACOW)) {
 503                                 if (!btrfs_test_opt(info, COMPRESS) ||
 504                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 505                                         btrfs_info(info,
 506                                                    "setting nodatacow, compression disabled");
 507                                 } else {
 508                                         btrfs_info(info, "setting nodatacow");
 509                                 }
 510                         }
 511                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 512                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 513                         btrfs_set_opt(info->mount_opt, NODATACOW);
 514                         btrfs_set_opt(info->mount_opt, NODATASUM);
 515                         break;
 516                 case Opt_datacow:
 517                         btrfs_clear_and_info(info, NODATACOW,
 518                                              "setting datacow");
 519                         break;
 520                 case Opt_compress_force:
 521                 case Opt_compress_force_type:
 522                         compress_force = true;
 523                         /* Fallthrough */
 524                 case Opt_compress:
 525                 case Opt_compress_type:
 526                         saved_compress_type = btrfs_test_opt(info,
 527                                                              COMPRESS) ?
 528                                 info->compress_type : BTRFS_COMPRESS_NONE;
 529                         saved_compress_force =
 530                                 btrfs_test_opt(info, FORCE_COMPRESS);
 531                         if (token == Opt_compress ||
 532                             token == Opt_compress_force ||
 533                             strncmp(args[0].from, "zlib", 4) == 0) {
 534                                 compress_type = "zlib";
 535
 536                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 537                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 538                                 /*
 539                                  * args[0] contains uninitialized data since
 540                                  * for these tokens we don't expect any
 541                                  * parameter.
 542                                  */
 543                                 if (token != Opt_compress &&
 544                                     token != Opt_compress_force)
 545                                         info->compress_level =
 546                                           btrfs_compress_str2level(args[0].from);
 547                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 548                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 549                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 550                                 no_compress = 0;
 551                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 552                                 compress_type = "lzo";
 553                                 info->compress_type = BTRFS_COMPRESS_LZO;
 554                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 555                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 556                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 557                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 558                                 no_compress = 0;
 559                         } else if (strcmp(args[0].from, "zstd") == 0) {
 560                                 compress_type = "zstd";
 561                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 562                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 563                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 564                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 565                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 566                                 no_compress = 0;
 567                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 568                                 compress_type = "no";
 569                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 570                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 571                                 compress_force = false;
 572                                 no_compress++;
 573                         } else {
 574                                 ret = -EINVAL;
 575                                 goto out;
 576                         }
 577
 578                         if (compress_force) {
 579                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 580                         } else {
 581                                 /*
 582                                  * If we remount from compress-force=xxx to
 583                                  * compress=xxx, we need clear FORCE_COMPRESS
 584                                  * flag, otherwise, there is no way for users
 585                                  * to disable forcible compression separately.
 586                                  */
 587                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 588                         }
 589                         if ((btrfs_test_opt(info, COMPRESS) &&
 590                              (info->compress_type != saved_compress_type ||
 591                               compress_force != saved_compress_force)) ||
 592                             (!btrfs_test_opt(info, COMPRESS) &&
 593                              no_compress == 1)) {
 594                                 btrfs_info(info, "%s %s compression, level %d",
 595                                            (compress_force) ? "force" : "use",
 596                                            compress_type, info->compress_level);
 597                         }
 598                         compress_force = false;
 599                         break;
 600                 case Opt_ssd:
 601                         btrfs_set_and_info(info, SSD,
 602                                            "enabling ssd optimizations");
 603                         btrfs_clear_opt(info->mount_opt, NOSSD);
 604                         break;
 605                 case Opt_ssd_spread:
 606                         btrfs_set_and_info(info, SSD,
 607                                            "enabling ssd optimizations");
 608                         btrfs_set_and_info(info, SSD_SPREAD,
 609                                            "using spread ssd allocation scheme");
 610                         btrfs_clear_opt(info->mount_opt, NOSSD);
 611                         break;
 612                 case Opt_nossd:
 613                         btrfs_set_opt(info->mount_opt, NOSSD);
 614                         btrfs_clear_and_info(info, SSD,
 615                                              "not using ssd optimizations");
 616                         /* Fallthrough */
 617                 case Opt_nossd_spread:
 618                         btrfs_clear_and_info(info, SSD_SPREAD,
 619                                              "not using spread ssd allocation scheme");
 620                         break;
 621                 case Opt_barrier:
 622                         btrfs_clear_and_info(info, NOBARRIER,
 623                                              "turning on barriers");
 624                         break;
 625                 case Opt_nobarrier:
 626                         btrfs_set_and_info(info, NOBARRIER,
 627                                            "turning off barriers");
 628                         break;
 629                 case Opt_thread_pool:
 630                         ret = match_int(&args[0], &intarg);
 631                         if (ret) {
 632                                 goto out;
 633                         } else if (intarg == 0) {
 634                                 ret = -EINVAL;
 635                                 goto out;
 636                         }
 637                         info->thread_pool_size = intarg;
 638                         break;
 639                 case Opt_max_inline:
 640                         num = match_strdup(&args[0]);
 641                         if (num) {
 642                                 info->max_inline = memparse(num, NULL);
 643                                 kfree(num);
 644
 645                                 if (info->max_inline) {
 646                                         info->max_inline = min_t(u64,
 647                                                 info->max_inline,
 648                                                 info->sectorsize);
 649                                 }
 650                                 btrfs_info(info, "max_inline at %llu",
 651                                            info->max_inline);
 652                         } else {
 653                                 ret = -ENOMEM;
 654                                 goto out;
 655                         }
 656                         break;
 657                 case Opt_alloc_start:
 658                         btrfs_info(info,
 659                                 "option alloc_start is obsolete, ignored");
 660                         break;
 661                 case Opt_acl:
 662 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 663                         info->sb->s_flags |= SB_POSIXACL;
 664                         break;
 665 #else
 666                         btrfs_err(info, "support for ACL not compiled in!");
 667                         ret = -EINVAL;
 668                         goto out;
 669 #endif
 670                 case Opt_noacl:
 671                         info->sb->s_flags &= ~SB_POSIXACL;
 672                         break;
 673                 case Opt_notreelog:
 674                         btrfs_set_and_info(info, NOTREELOG,
 675                                            "disabling tree log");
 676                         break;
 677                 case Opt_treelog:
 678                         btrfs_clear_and_info(info, NOTREELOG,
 679                                              "enabling tree log");
 680                         break;
 681                 case Opt_norecovery:
 682                 case Opt_nologreplay:
 683                         btrfs_set_and_info(info, NOLOGREPLAY,
 684                                            "disabling log replay at mount time");
 685                         break;
 686                 case Opt_flushoncommit:
 687                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 688                                            "turning on flush-on-commit");
 689                         break;
 690                 case Opt_noflushoncommit:
 691                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 692                                              "turning off flush-on-commit");
 693                         break;
 694                 case Opt_ratio:
 695                         ret = match_int(&args[0], &intarg);
 696                         if (ret)
 697                                 goto out;
 698                         info->metadata_ratio = intarg;
 699                         btrfs_info(info, "metadata ratio %u",
 700                                    info->metadata_ratio);
 701                         break;
 702                 case Opt_discard:
 703                         btrfs_set_and_info(info, DISCARD,
 704                                            "turning on discard");
 705                         break;
 706                 case Opt_nodiscard:
 707                         btrfs_clear_and_info(info, DISCARD,
 708                                              "turning off discard");
 709                         break;
 710                 case Opt_space_cache:
 711                 case Opt_space_cache_version:
 712                         if (token == Opt_space_cache ||
 713                             strcmp(args[0].from, "v1") == 0) {
 714                                 btrfs_clear_opt(info->mount_opt,
 715                                                 FREE_SPACE_TREE);
 716                                 btrfs_set_and_info(info, SPACE_CACHE,
 717                                            "enabling disk space caching");
 718                         } else if (strcmp(args[0].from, "v2") == 0) {
 719                                 btrfs_clear_opt(info->mount_opt,
 720                                                 SPACE_CACHE);
 721                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 722                                                    "enabling free space tree");
 723                         } else {
 724                                 ret = -EINVAL;
 725                                 goto out;
 726                         }
 727                         break;
 728                 case Opt_rescan_uuid_tree:
 729                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 730                         break;
 731                 case Opt_no_space_cache:
 732                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 733                                 btrfs_clear_and_info(info, SPACE_CACHE,
 734                                              "disabling disk space caching");
 735                         }
 736                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 737                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 738                                              "disabling free space tree");
 739                         }
 740                         break;
 741                 case Opt_inode_cache:
 742                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 743                                            "enabling inode map caching");
 744                         break;
 745                 case Opt_noinode_cache:
 746                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 747                                              "disabling inode map caching");
 748                         break;
 749                 case Opt_clear_cache:
 750                         btrfs_set_and_info(info, CLEAR_CACHE,
 751                                            "force clearing of disk cache");
 752                         break;
 753                 case Opt_user_subvol_rm_allowed:
 754                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 755                         break;
 756                 case Opt_enospc_debug:
 757                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 758                         break;
 759                 case Opt_noenospc_debug:
 760                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 761                         break;
 762                 case Opt_defrag:
 763                         btrfs_set_and_info(info, AUTO_DEFRAG,
 764                                            "enabling auto defrag");
 765                         break;
 766                 case Opt_nodefrag:
 767                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 768                                              "disabling auto defrag");
 769                         break;
 770                 case Opt_recovery:
 771                         btrfs_warn(info,
 772                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 773                 case Opt_usebackuproot:
 774                         btrfs_info(info,
 775                                    "trying to use backup root at mount time");
 776                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 777                         break;
 778                 case Opt_skip_balance:
 779                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 780                         break;
 781 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 782                 case Opt_check_integrity_including_extent_data:
 783                         btrfs_info(info,
 784                                    "enabling check integrity including extent data");
 785                         btrfs_set_opt(info->mount_opt,
 786                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 787                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 788                         break;
 789                 case Opt_check_integrity:
 790                         btrfs_info(info, "enabling check integrity");
 791                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 792                         break;
 793                 case Opt_check_integrity_print_mask:
 794                         ret = match_int(&args[0], &intarg);
 795                         if (ret)
 796                                 goto out;
 797                         info->check_integrity_print_mask = intarg;
 798                         btrfs_info(info, "check_integrity_print_mask 0x%x",
 799                                    info->check_integrity_print_mask);
 800                         break;
 801 #else
 802                 case Opt_check_integrity_including_extent_data:
 803                 case Opt_check_integrity:
 804                 case Opt_check_integrity_print_mask:
 805                         btrfs_err(info,
 806                                   "support for check_integrity* not compiled in!");
 807                         ret = -EINVAL;
 808                         goto out;
 809 #endif
 810                 case Opt_fatal_errors:
 811                         if (strcmp(args[0].from, "panic") == 0)
 812                                 btrfs_set_opt(info->mount_opt,
 813                                               PANIC_ON_FATAL_ERROR);
 814                         else if (strcmp(args[0].from, "bug") == 0)
 815                                 btrfs_clear_opt(info->mount_opt,
 816                                               PANIC_ON_FATAL_ERROR);
 817                         else {
 818                                 ret = -EINVAL;
 819                                 goto out;
 820                         }
 821                         break;
 822                 case Opt_commit_interval:
 823                         intarg = 0;
 824                         ret = match_int(&args[0], &intarg);
 825                         if (ret)
 826                                 goto out;
 827                         if (intarg == 0) {
 828                                 btrfs_info(info,
 829                                            "using default commit interval %us",
 830                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 831                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
 832                         } else if (intarg > 300) {
 833                                 btrfs_warn(info, "excessive commit interval %d",
 834                                            intarg);
 835                         }
 836                         info->commit_interval = intarg;
 837                         break;
 838 #ifdef CONFIG_BTRFS_DEBUG
 839                 case Opt_fragment_all:
 840                         btrfs_info(info, "fragmenting all space");
 841                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 842                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 843                         break;
 844                 case Opt_fragment_metadata:
 845                         btrfs_info(info, "fragmenting metadata");
 846                         btrfs_set_opt(info->mount_opt,
 847                                       FRAGMENT_METADATA);
 848                         break;
 849                 case Opt_fragment_data:
 850                         btrfs_info(info, "fragmenting data");
 851                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 852                         break;
 853 #endif
 854 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 855                 case Opt_ref_verify:
 856                         btrfs_info(info, "doing ref verification");
 857                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 858                         break;
 859 #endif
 860                 case Opt_err:
 861                         btrfs_info(info, "unrecognized mount option '%s'", p);
 862                         ret = -EINVAL;
 863                         goto out;
 864                 default:
 865                         break;
 866                 }
 867         }
 868 check:
 869         /*
 870          * Extra check for current option against current flag
 871          */
 872         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & SB_RDONLY)) {
 873                 btrfs_err(info,
 874                           "nologreplay must be used with ro mount option");
 875                 ret = -EINVAL;
 876         }
 877 out:
 878         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 879             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 880             !btrfs_test_opt(info, CLEAR_CACHE)) {
 881                 btrfs_err(info, "cannot disable free space tree");
 882                 ret = -EINVAL;
 883
 884         }
 885         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 886                 btrfs_info(info, "disk space caching is enabled");
 887         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 888                 btrfs_info(info, "using free space tree");
 889         return ret;
 890 }
 891
 892 /*
 893  * Parse mount options that are required early in the mount process.
 894  *
 895  * All other options will be parsed on much later in the mount process and
 896  * only when we need to allocate a new super block.
 897  */
 898 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 899                 void *holder, struct btrfs_fs_devices **fs_devices)
 900 {
 901         substring_t args[MAX_OPT_ARGS];
 902         char *device_name, *opts, *orig, *p;
 903         int error = 0;
 904
 905         if (!options)
 906                 return 0;
 907
 908         /*
 909          * strsep changes the string, duplicate it because btrfs_parse_options
 910          * gets called later
 911          */
 912         opts = kstrdup(options, GFP_KERNEL);
 913         if (!opts)
 914                 return -ENOMEM;
 915         orig = opts;
 916
 917         while ((p = strsep(&opts, ",")) != NULL) {
 918                 int token;
 919
 920                 if (!*p)
 921                         continue;
 922
 923                 token = match_token(p, tokens, args);
 924                 if (token == Opt_device) {
 925                         device_name = match_strdup(&args[0]);
 926                         if (!device_name) {
 927                                 error = -ENOMEM;
 928                                 goto out;
 929                         }
 930                         error = btrfs_scan_one_device(device_name,
 931                                         flags, holder, fs_devices);
 932                         kfree(device_name);
 933                         if (error)
 934                                 goto out;
 935                 }
 936         }
 937
 938 out:
 939         kfree(orig);
 940         return error;
 941 }
 942
 943 /*
 944  * Parse mount options that are related to subvolume id
 945  *
 946  * The value is later passed to mount_subvol()
 947  */
 948 static int btrfs_parse_subvol_options(const char *options, fmode_t flags,
 949                 char **subvol_name, u64 *subvol_objectid)
 950 {
 951         substring_t args[MAX_OPT_ARGS];
 952         char *opts, *orig, *p;
 953         int error = 0;
 954         u64 subvolid;
 955
 956         if (!options)
 957                 return 0;
 958
 959         /*
 960          * strsep changes the string, duplicate it because
 961          * btrfs_parse_early_options gets called later
 962          */
 963         opts = kstrdup(options, GFP_KERNEL);
 964         if (!opts)
 965                 return -ENOMEM;
 966         orig = opts;
 967
 968         while ((p = strsep(&opts, ",")) != NULL) {
 969                 int token;
 970                 if (!*p)
 971                         continue;
 972
 973                 token = match_token(p, tokens, args);
 974                 switch (token) {
 975                 case Opt_subvol:
 976                         kfree(*subvol_name);
 977                         *subvol_name = match_strdup(&args[0]);
 978                         if (!*subvol_name) {
 979                                 error = -ENOMEM;
 980                                 goto out;
 981                         }
 982                         break;
 983                 case Opt_subvolid:
 984                         error = match_u64(&args[0], &subvolid);
 985                         if (error)
 986                                 goto out;
 987
 988                         /* we want the original fs_tree */
 989                         if (subvolid == 0)
 990                                 subvolid = BTRFS_FS_TREE_OBJECTID;
 991
 992                         *subvol_objectid = subvolid;
 993                         break;
 994                 case Opt_subvolrootid:
 995                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
 996                         break;
 997                 default:
 998                         break;
 999                 }
1000         }
1001
1002 out:
1003         kfree(orig);
1004         return error;
1005 }
1006
1007 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
1008                                            u64 subvol_objectid)
1009 {
1010         struct btrfs_root *root = fs_info->tree_root;
1011         struct btrfs_root *fs_root;
1012         struct btrfs_root_ref *root_ref;
1013         struct btrfs_inode_ref *inode_ref;
1014         struct btrfs_key key;
1015         struct btrfs_path *path = NULL;
1016         char *name = NULL, *ptr;
1017         u64 dirid;
1018         int len;
1019         int ret;
1020
1021         path = btrfs_alloc_path();
1022         if (!path) {
1023                 ret = -ENOMEM;
1024                 goto err;
1025         }
1026         path->leave_spinning = 1;
1027
1028         name = kmalloc(PATH_MAX, GFP_KERNEL);
1029         if (!name) {
1030                 ret = -ENOMEM;
1031                 goto err;
1032         }
1033         ptr = name + PATH_MAX - 1;
1034         ptr[0] = '\0';
1035
1036         /*
1037          * Walk up the subvolume trees in the tree of tree roots by root
1038          * backrefs until we hit the top-level subvolume.
1039          */
1040         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1041                 key.objectid = subvol_objectid;
1042                 key.type = BTRFS_ROOT_BACKREF_KEY;
1043                 key.offset = (u64)-1;
1044
1045                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1046                 if (ret < 0) {
1047                         goto err;
1048                 } else if (ret > 0) {
1049                         ret = btrfs_previous_item(root, path, subvol_objectid,
1050                                                   BTRFS_ROOT_BACKREF_KEY);
1051                         if (ret < 0) {
1052                                 goto err;
1053                         } else if (ret > 0) {
1054                                 ret = -ENOENT;
1055                                 goto err;
1056                         }
1057                 }
1058
1059                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1060                 subvol_objectid = key.offset;
1061
1062                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1063                                           struct btrfs_root_ref);
1064                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1065                 ptr -= len + 1;
1066                 if (ptr < name) {
1067                         ret = -ENAMETOOLONG;
1068                         goto err;
1069                 }
1070                 read_extent_buffer(path->nodes[0], ptr + 1,
1071                                    (unsigned long)(root_ref + 1), len);
1072                 ptr[0] = '/';
1073                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1074                 btrfs_release_path(path);
1075
1076                 key.objectid = subvol_objectid;
1077                 key.type = BTRFS_ROOT_ITEM_KEY;
1078                 key.offset = (u64)-1;
1079                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1080                 if (IS_ERR(fs_root)) {
1081                         ret = PTR_ERR(fs_root);
1082                         goto err;
1083                 }
1084
1085                 /*
1086                  * Walk up the filesystem tree by inode refs until we hit the
1087                  * root directory.
1088                  */
1089                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1090                         key.objectid = dirid;
1091                         key.type = BTRFS_INODE_REF_KEY;
1092                         key.offset = (u64)-1;
1093
1094                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1095                         if (ret < 0) {
1096                                 goto err;
1097                         } else if (ret > 0) {
1098                                 ret = btrfs_previous_item(fs_root, path, dirid,
1099                                                           BTRFS_INODE_REF_KEY);
1100                                 if (ret < 0) {
1101                                         goto err;
1102                                 } else if (ret > 0) {
1103                                         ret = -ENOENT;
1104                                         goto err;
1105                                 }
1106                         }
1107
1108                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1109                         dirid = key.offset;
1110
1111                         inode_ref = btrfs_item_ptr(path->nodes[0],
1112                                                    path->slots[0],
1113                                                    struct btrfs_inode_ref);
1114                         len = btrfs_inode_ref_name_len(path->nodes[0],
1115                                                        inode_ref);
1116                         ptr -= len + 1;
1117                         if (ptr < name) {
1118                                 ret = -ENAMETOOLONG;
1119                                 goto err;
1120                         }
1121                         read_extent_buffer(path->nodes[0], ptr + 1,
1122                                            (unsigned long)(inode_ref + 1), len);
1123                         ptr[0] = '/';
1124                         btrfs_release_path(path);
1125                 }
1126         }
1127
1128         btrfs_free_path(path);
1129         if (ptr == name + PATH_MAX - 1) {
1130                 name[0] = '/';
1131                 name[1] = '\0';
1132         } else {
1133                 memmove(name, ptr, name + PATH_MAX - ptr);
1134         }
1135         return name;
1136
1137 err:
1138         btrfs_free_path(path);
1139         kfree(name);
1140         return ERR_PTR(ret);
1141 }
1142
1143 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1144 {
1145         struct btrfs_root *root = fs_info->tree_root;
1146         struct btrfs_dir_item *di;
1147         struct btrfs_path *path;
1148         struct btrfs_key location;
1149         u64 dir_id;
1150
1151         path = btrfs_alloc_path();
1152         if (!path)
1153                 return -ENOMEM;
1154         path->leave_spinning = 1;
1155
1156         /*
1157          * Find the "default" dir item which points to the root item that we
1158          * will mount by default if we haven't been given a specific subvolume
1159          * to mount.
1160          */
1161         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1162         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1163         if (IS_ERR(di)) {
1164                 btrfs_free_path(path);
1165                 return PTR_ERR(di);
1166         }
1167         if (!di) {
1168                 /*
1169                  * Ok the default dir item isn't there.  This is weird since
1170                  * it's always been there, but don't freak out, just try and
1171                  * mount the top-level subvolume.
1172                  */
1173                 btrfs_free_path(path);
1174                 *objectid = BTRFS_FS_TREE_OBJECTID;
1175                 return 0;
1176         }
1177
1178         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1179         btrfs_free_path(path);
1180         *objectid = location.objectid;
1181         return 0;
1182 }
1183
1184 static int btrfs_fill_super(struct super_block *sb,
1185                             struct btrfs_fs_devices *fs_devices,
1186                             void *data)
1187 {
1188         struct inode *inode;
1189         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1190         struct btrfs_key key;
1191         int err;
1192
1193         sb->s_maxbytes = MAX_LFS_FILESIZE;
1194         sb->s_magic = BTRFS_SUPER_MAGIC;
1195         sb->s_op = &btrfs_super_ops;
1196         sb->s_d_op = &btrfs_dentry_operations;
1197         sb->s_export_op = &btrfs_export_ops;
1198         sb->s_xattr = btrfs_xattr_handlers;
1199         sb->s_time_gran = 1;
1200 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1201         sb->s_flags |= SB_POSIXACL;
1202 #endif
1203         sb->s_flags |= SB_I_VERSION;
1204         sb->s_iflags |= SB_I_CGROUPWB;
1205
1206         err = super_setup_bdi(sb);
1207         if (err) {
1208                 btrfs_err(fs_info, "super_setup_bdi failed");
1209                 return err;
1210         }
1211
1212         err = open_ctree(sb, fs_devices, (char *)data);
1213         if (err) {
1214                 btrfs_err(fs_info, "open_ctree failed");
1215                 return err;
1216         }
1217
1218         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1219         key.type = BTRFS_INODE_ITEM_KEY;
1220         key.offset = 0;
1221         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1222         if (IS_ERR(inode)) {
1223                 err = PTR_ERR(inode);
1224                 goto fail_close;
1225         }
1226
1227         sb->s_root = d_make_root(inode);
1228         if (!sb->s_root) {
1229                 err = -ENOMEM;
1230                 goto fail_close;
1231         }
1232
1233         cleancache_init_fs(sb);
1234         sb->s_flags |= SB_ACTIVE;
1235         return 0;
1236
1237 fail_close:
1238         close_ctree(fs_info);
1239         return err;
1240 }
1241
1242 int btrfs_sync_fs(struct super_block *sb, int wait)
1243 {
1244         struct btrfs_trans_handle *trans;
1245         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1246         struct btrfs_root *root = fs_info->tree_root;
1247
1248         trace_btrfs_sync_fs(fs_info, wait);
1249
1250         if (!wait) {
1251                 filemap_flush(fs_info->btree_inode->i_mapping);
1252                 return 0;
1253         }
1254
1255         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1256
1257         trans = btrfs_attach_transaction_barrier(root);
1258         if (IS_ERR(trans)) {
1259                 /* no transaction, don't bother */
1260                 if (PTR_ERR(trans) == -ENOENT) {
1261                         /*
1262                          * Exit unless we have some pending changes
1263                          * that need to go through commit
1264                          */
1265                         if (fs_info->pending_changes == 0)
1266                                 return 0;
1267                         /*
1268                          * A non-blocking test if the fs is frozen. We must not
1269                          * start a new transaction here otherwise a deadlock
1270                          * happens. The pending operations are delayed to the
1271                          * next commit after thawing.
1272                          */
1273                         if (sb_start_write_trylock(sb))
1274                                 sb_end_write(sb);
1275                         else
1276                                 return 0;
1277                         trans = btrfs_start_transaction(root, 0);
1278                 }
1279                 if (IS_ERR(trans))
1280                         return PTR_ERR(trans);
1281         }
1282         return btrfs_commit_transaction(trans);
1283 }
1284
1285 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1286 {
1287         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1288         const char *compress_type;
1289
1290         if (btrfs_test_opt(info, DEGRADED))
1291                 seq_puts(seq, ",degraded");
1292         if (btrfs_test_opt(info, NODATASUM))
1293                 seq_puts(seq, ",nodatasum");
1294         if (btrfs_test_opt(info, NODATACOW))
1295                 seq_puts(seq, ",nodatacow");
1296         if (btrfs_test_opt(info, NOBARRIER))
1297                 seq_puts(seq, ",nobarrier");
1298         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1299                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1300         if (info->thread_pool_size !=  min_t(unsigned long,
1301                                              num_online_cpus() + 2, 8))
1302                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1303         if (btrfs_test_opt(info, COMPRESS)) {
1304                 compress_type = btrfs_compress_type2str(info->compress_type);
1305                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1306                         seq_printf(seq, ",compress-force=%s", compress_type);
1307                 else
1308                         seq_printf(seq, ",compress=%s", compress_type);
1309                 if (info->compress_level)
1310                         seq_printf(seq, ":%d", info->compress_level);
1311         }
1312         if (btrfs_test_opt(info, NOSSD))
1313                 seq_puts(seq, ",nossd");
1314         if (btrfs_test_opt(info, SSD_SPREAD))
1315                 seq_puts(seq, ",ssd_spread");
1316         else if (btrfs_test_opt(info, SSD))
1317                 seq_puts(seq, ",ssd");
1318         if (btrfs_test_opt(info, NOTREELOG))
1319                 seq_puts(seq, ",notreelog");
1320         if (btrfs_test_opt(info, NOLOGREPLAY))
1321                 seq_puts(seq, ",nologreplay");
1322         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1323                 seq_puts(seq, ",flushoncommit");
1324         if (btrfs_test_opt(info, DISCARD))
1325                 seq_puts(seq, ",discard");
1326         if (!(info->sb->s_flags & SB_POSIXACL))
1327                 seq_puts(seq, ",noacl");
1328         if (btrfs_test_opt(info, SPACE_CACHE))
1329                 seq_puts(seq, ",space_cache");
1330         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1331                 seq_puts(seq, ",space_cache=v2");
1332         else
1333                 seq_puts(seq, ",nospace_cache");
1334         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1335                 seq_puts(seq, ",rescan_uuid_tree");
1336         if (btrfs_test_opt(info, CLEAR_CACHE))
1337                 seq_puts(seq, ",clear_cache");
1338         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1339                 seq_puts(seq, ",user_subvol_rm_allowed");
1340         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1341                 seq_puts(seq, ",enospc_debug");
1342         if (btrfs_test_opt(info, AUTO_DEFRAG))
1343                 seq_puts(seq, ",autodefrag");
1344         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1345                 seq_puts(seq, ",inode_cache");
1346         if (btrfs_test_opt(info, SKIP_BALANCE))
1347                 seq_puts(seq, ",skip_balance");
1348 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1349         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1350                 seq_puts(seq, ",check_int_data");
1351         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1352                 seq_puts(seq, ",check_int");
1353         if (info->check_integrity_print_mask)
1354                 seq_printf(seq, ",check_int_print_mask=%d",
1355                                 info->check_integrity_print_mask);
1356 #endif
1357         if (info->metadata_ratio)
1358                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1359         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1360                 seq_puts(seq, ",fatal_errors=panic");
1361         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1362                 seq_printf(seq, ",commit=%u", info->commit_interval);
1363 #ifdef CONFIG_BTRFS_DEBUG
1364         if (btrfs_test_opt(info, FRAGMENT_DATA))
1365                 seq_puts(seq, ",fragment=data");
1366         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1367                 seq_puts(seq, ",fragment=metadata");
1368 #endif
1369         if (btrfs_test_opt(info, REF_VERIFY))
1370                 seq_puts(seq, ",ref_verify");
1371         seq_printf(seq, ",subvolid=%llu",
1372                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1373         seq_puts(seq, ",subvol=");
1374         seq_dentry(seq, dentry, " \t\n\\");
1375         return 0;
1376 }
1377
1378 static int btrfs_test_super(struct super_block *s, void *data)
1379 {
1380         struct btrfs_fs_info *p = data;
1381         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1382
1383         return fs_info->fs_devices == p->fs_devices;
1384 }
1385
1386 static int btrfs_set_super(struct super_block *s, void *data)
1387 {
1388         int err = set_anon_super(s, data);
1389         if (!err)
1390                 s->s_fs_info = data;
1391         return err;
1392 }
1393
1394 /*
1395  * subvolumes are identified by ino 256
1396  */
1397 static inline int is_subvolume_inode(struct inode *inode)
1398 {
1399         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1400                 return 1;
1401         return 0;
1402 }
1403
1404 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1405                                    const char *device_name, struct vfsmount *mnt)
1406 {
1407         struct dentry *root;
1408         int ret;
1409
1410         if (!subvol_name) {
1411                 if (!subvol_objectid) {
1412                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1413                                                           &subvol_objectid);
1414                         if (ret) {
1415                                 root = ERR_PTR(ret);
1416                                 goto out;
1417                         }
1418                 }
1419                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1420                                                             subvol_objectid);
1421                 if (IS_ERR(subvol_name)) {
1422                         root = ERR_CAST(subvol_name);
1423                         subvol_name = NULL;
1424                         goto out;
1425                 }
1426
1427         }
1428
1429         root = mount_subtree(mnt, subvol_name);
1430         /* mount_subtree() drops our reference on the vfsmount. */
1431         mnt = NULL;
1432
1433         if (!IS_ERR(root)) {
1434                 struct super_block *s = root->d_sb;
1435                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1436                 struct inode *root_inode = d_inode(root);
1437                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1438
1439                 ret = 0;
1440                 if (!is_subvolume_inode(root_inode)) {
1441                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1442                                subvol_name);
1443                         ret = -EINVAL;
1444                 }
1445                 if (subvol_objectid && root_objectid != subvol_objectid) {
1446                         /*
1447                          * This will also catch a race condition where a
1448                          * subvolume which was passed by ID is renamed and
1449                          * another subvolume is renamed over the old location.
1450                          */
1451                         btrfs_err(fs_info,
1452                                   "subvol '%s' does not match subvolid %llu",
1453                                   subvol_name, subvol_objectid);
1454                         ret = -EINVAL;
1455                 }
1456                 if (ret) {
1457                         dput(root);
1458                         root = ERR_PTR(ret);
1459                         deactivate_locked_super(s);
1460                 }
1461         }
1462
1463 out:
1464         mntput(mnt);
1465         kfree(subvol_name);
1466         return root;
1467 }
1468
1469 static int parse_security_options(char *orig_opts,
1470                                   struct security_mnt_opts *sec_opts)
1471 {
1472         char *secdata = NULL;
1473         int ret = 0;
1474
1475         secdata = alloc_secdata();
1476         if (!secdata)
1477                 return -ENOMEM;
1478         ret = security_sb_copy_data(orig_opts, secdata);
1479         if (ret) {
1480                 free_secdata(secdata);
1481                 return ret;
1482         }
1483         ret = security_sb_parse_opts_str(secdata, sec_opts);
1484         free_secdata(secdata);
1485         return ret;
1486 }
1487
1488 static int setup_security_options(struct btrfs_fs_info *fs_info,
1489                                   struct super_block *sb,
1490                                   struct security_mnt_opts *sec_opts)
1491 {
1492         int ret = 0;
1493
1494         /*
1495          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1496          * is valid.
1497          */
1498         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1499         if (ret)
1500                 return ret;
1501
1502 #ifdef CONFIG_SECURITY
1503         if (!fs_info->security_opts.num_mnt_opts) {
1504                 /* first time security setup, copy sec_opts to fs_info */
1505                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1506         } else {
1507                 /*
1508                  * Since SELinux (the only one supporting security_mnt_opts)
1509                  * does NOT support changing context during remount/mount of
1510                  * the same sb, this must be the same or part of the same
1511                  * security options, just free it.
1512                  */
1513                 security_free_mnt_opts(sec_opts);
1514         }
1515 #endif
1516         return ret;
1517 }
1518
1519 /*
1520  * Find a superblock for the given device / mount point.
1521  *
1522  * Note: This is based on mount_bdev from fs/super.c with a few additions
1523  *       for multiple device setup.  Make sure to keep it in sync.
1524  */
1525 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1526                 int flags, const char *device_name, void *data)
1527 {
1528         struct block_device *bdev = NULL;
1529         struct super_block *s;
1530         struct btrfs_fs_devices *fs_devices = NULL;
1531         struct btrfs_fs_info *fs_info = NULL;
1532         struct security_mnt_opts new_sec_opts;
1533         fmode_t mode = FMODE_READ;
1534         int error = 0;
1535
1536         if (!(flags & SB_RDONLY))
1537                 mode |= FMODE_WRITE;
1538
1539         error = btrfs_parse_early_options(data, mode, fs_type,
1540                                           &fs_devices);
1541         if (error) {
1542                 return ERR_PTR(error);
1543         }
1544
1545         security_init_mnt_opts(&new_sec_opts);
1546         if (data) {
1547                 error = parse_security_options(data, &new_sec_opts);
1548                 if (error)
1549                         return ERR_PTR(error);
1550         }
1551
1552         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1553         if (error)
1554                 goto error_sec_opts;
1555
1556         /*
1557          * Setup a dummy root and fs_info for test/set super.  This is because
1558          * we don't actually fill this stuff out until open_ctree, but we need
1559          * it for searching for existing supers, so this lets us do that and
1560          * then open_ctree will properly initialize everything later.
1561          */
1562         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1563         if (!fs_info) {
1564                 error = -ENOMEM;
1565                 goto error_sec_opts;
1566         }
1567
1568         fs_info->fs_devices = fs_devices;
1569
1570         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1571         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1572         security_init_mnt_opts(&fs_info->security_opts);
1573         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1574                 error = -ENOMEM;
1575                 goto error_fs_info;
1576         }
1577
1578         error = btrfs_open_devices(fs_devices, mode, fs_type);
1579         if (error)
1580                 goto error_fs_info;
1581
1582         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1583                 error = -EACCES;
1584                 goto error_close_devices;
1585         }
1586
1587         bdev = fs_devices->latest_bdev;
1588         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1589                  fs_info);
1590         if (IS_ERR(s)) {
1591                 error = PTR_ERR(s);
1592                 goto error_close_devices;
1593         }
1594
1595         if (s->s_root) {
1596                 btrfs_close_devices(fs_devices);
1597                 free_fs_info(fs_info);
1598                 if ((flags ^ s->s_flags) & SB_RDONLY)
1599                         error = -EBUSY;
1600         } else {
1601                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1602                 btrfs_sb(s)->bdev_holder = fs_type;
1603                 error = btrfs_fill_super(s, fs_devices, data);
1604         }
1605         if (error) {
1606                 deactivate_locked_super(s);
1607                 goto error_sec_opts;
1608         }
1609
1610         fs_info = btrfs_sb(s);
1611         error = setup_security_options(fs_info, s, &new_sec_opts);
1612         if (error) {
1613                 deactivate_locked_super(s);
1614                 goto error_sec_opts;
1615         }
1616
1617         return dget(s->s_root);
1618
1619 error_close_devices:
1620         btrfs_close_devices(fs_devices);
1621 error_fs_info:
1622         free_fs_info(fs_info);
1623 error_sec_opts:
1624         security_free_mnt_opts(&new_sec_opts);
1625         return ERR_PTR(error);
1626 }
1627
1628 /*
1629  * Mount function which is called by VFS layer.
1630  *
1631  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1632  * which needs vfsmount* of device's root (/).  This means device's root has to
1633  * be mounted internally in any case.
1634  *
1635  * Operation flow:
1636  *   1. Parse subvol id related options for later use in mount_subvol().
1637  *
1638  *   2. Mount device's root (/) by calling vfs_kern_mount().
1639  *
1640  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1641  *      first place. In order to avoid calling btrfs_mount() again, we use
1642  *      different file_system_type which is not registered to VFS by
1643  *      register_filesystem() (btrfs_root_fs_type). As a result,
1644  *      btrfs_mount_root() is called. The return value will be used by
1645  *      mount_subtree() in mount_subvol().
1646  *
1647  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1648  *      "btrfs subvolume set-default", mount_subvol() is called always.
1649  */
1650 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1651                 const char *device_name, void *data)
1652 {
1653         struct vfsmount *mnt_root;
1654         struct dentry *root;
1655         fmode_t mode = FMODE_READ;
1656         char *subvol_name = NULL;
1657         u64 subvol_objectid = 0;
1658         int error = 0;
1659
1660         if (!(flags & SB_RDONLY))
1661                 mode |= FMODE_WRITE;
1662
1663         error = btrfs_parse_subvol_options(data, mode,
1664                                           &subvol_name, &subvol_objectid);
1665         if (error) {
1666                 kfree(subvol_name);
1667                 return ERR_PTR(error);
1668         }
1669
1670         /* mount device's root (/) */
1671         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1672         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1673                 if (flags & SB_RDONLY) {
1674                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1675                                 flags & ~SB_RDONLY, device_name, data);
1676                 } else {
1677                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1678                                 flags | SB_RDONLY, device_name, data);
1679                         if (IS_ERR(mnt_root)) {
1680                                 root = ERR_CAST(mnt_root);
1681                                 goto out;
1682                         }
1683
1684                         down_write(&mnt_root->mnt_sb->s_umount);
1685                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1686                         up_write(&mnt_root->mnt_sb->s_umount);
1687                         if (error < 0) {
1688                                 root = ERR_PTR(error);
1689                                 mntput(mnt_root);
1690                                 goto out;
1691                         }
1692                 }
1693         }
1694         if (IS_ERR(mnt_root)) {
1695                 root = ERR_CAST(mnt_root);
1696                 goto out;
1697         }
1698
1699         /* mount_subvol() will free subvol_name and mnt_root */
1700         root = mount_subvol(subvol_name, subvol_objectid, device_name, mnt_root);
1701
1702 out:
1703         return root;
1704 }
1705
1706 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1707                                      u32 new_pool_size, u32 old_pool_size)
1708 {
1709         if (new_pool_size == old_pool_size)
1710                 return;
1711
1712         fs_info->thread_pool_size = new_pool_size;
1713
1714         btrfs_info(fs_info, "resize thread pool %d -> %d",
1715                old_pool_size, new_pool_size);
1716
1717         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1718         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1719         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1720         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1721         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1722         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1723         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1724                                 new_pool_size);
1725         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1726         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1727         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1728         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1729         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1730                                 new_pool_size);
1731 }
1732
1733 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1734 {
1735         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1736 }
1737
1738 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1739                                        unsigned long old_opts, int flags)
1740 {
1741         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1742             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1743              (flags & SB_RDONLY))) {
1744                 /* wait for any defraggers to finish */
1745                 wait_event(fs_info->transaction_wait,
1746                            (atomic_read(&fs_info->defrag_running) == 0));
1747                 if (flags & SB_RDONLY)
1748                         sync_filesystem(fs_info->sb);
1749         }
1750 }
1751
1752 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1753                                          unsigned long old_opts)
1754 {
1755         /*
1756          * We need to cleanup all defragable inodes if the autodefragment is
1757          * close or the filesystem is read only.
1758          */
1759         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1760             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1761                 btrfs_cleanup_defrag_inodes(fs_info);
1762         }
1763
1764         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1765 }
1766
1767 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1768 {
1769         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1770         struct btrfs_root *root = fs_info->tree_root;
1771         unsigned old_flags = sb->s_flags;
1772         unsigned long old_opts = fs_info->mount_opt;
1773         unsigned long old_compress_type = fs_info->compress_type;
1774         u64 old_max_inline = fs_info->max_inline;
1775         u32 old_thread_pool_size = fs_info->thread_pool_size;
1776         u32 old_metadata_ratio = fs_info->metadata_ratio;
1777         int ret;
1778
1779         sync_filesystem(sb);
1780         btrfs_remount_prepare(fs_info);
1781
1782         if (data) {
1783                 struct security_mnt_opts new_sec_opts;
1784
1785                 security_init_mnt_opts(&new_sec_opts);
1786                 ret = parse_security_options(data, &new_sec_opts);
1787                 if (ret)
1788                         goto restore;
1789                 ret = setup_security_options(fs_info, sb,
1790                                              &new_sec_opts);
1791                 if (ret) {
1792                         security_free_mnt_opts(&new_sec_opts);
1793                         goto restore;
1794                 }
1795         }
1796
1797         ret = btrfs_parse_options(fs_info, data, *flags);
1798         if (ret) {
1799                 ret = -EINVAL;
1800                 goto restore;
1801         }
1802
1803         btrfs_remount_begin(fs_info, old_opts, *flags);
1804         btrfs_resize_thread_pool(fs_info,
1805                 fs_info->thread_pool_size, old_thread_pool_size);
1806
1807         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1808                 goto out;
1809
1810         if (*flags & SB_RDONLY) {
1811                 /*
1812                  * this also happens on 'umount -rf' or on shutdown, when
1813                  * the filesystem is busy.
1814                  */
1815                 cancel_work_sync(&fs_info->async_reclaim_work);
1816
1817                 /* wait for the uuid_scan task to finish */
1818                 down(&fs_info->uuid_tree_rescan_sem);
1819                 /* avoid complains from lockdep et al. */
1820                 up(&fs_info->uuid_tree_rescan_sem);
1821
1822                 sb->s_flags |= SB_RDONLY;
1823
1824                 /*
1825                  * Setting SB_RDONLY will put the cleaner thread to
1826                  * sleep at the next loop if it's already active.
1827                  * If it's already asleep, we'll leave unused block
1828                  * groups on disk until we're mounted read-write again
1829                  * unless we clean them up here.
1830                  */
1831                 btrfs_delete_unused_bgs(fs_info);
1832
1833                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1834                 btrfs_scrub_cancel(fs_info);
1835                 btrfs_pause_balance(fs_info);
1836
1837                 ret = btrfs_commit_super(fs_info);
1838                 if (ret)
1839                         goto restore;
1840         } else {
1841                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1842                         btrfs_err(fs_info,
1843                                 "Remounting read-write after error is not allowed");
1844                         ret = -EINVAL;
1845                         goto restore;
1846                 }
1847                 if (fs_info->fs_devices->rw_devices == 0) {
1848                         ret = -EACCES;
1849                         goto restore;
1850                 }
1851
1852                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1853                         btrfs_warn(fs_info,
1854                                 "too many missing devices, writeable remount is not allowed");
1855                         ret = -EACCES;
1856                         goto restore;
1857                 }
1858
1859                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1860                         ret = -EINVAL;
1861                         goto restore;
1862                 }
1863
1864                 ret = btrfs_cleanup_fs_roots(fs_info);
1865                 if (ret)
1866                         goto restore;
1867
1868                 /* recover relocation */
1869                 mutex_lock(&fs_info->cleaner_mutex);
1870                 ret = btrfs_recover_relocation(root);
1871                 mutex_unlock(&fs_info->cleaner_mutex);
1872                 if (ret)
1873                         goto restore;
1874
1875                 ret = btrfs_resume_balance_async(fs_info);
1876                 if (ret)
1877                         goto restore;
1878
1879                 ret = btrfs_resume_dev_replace_async(fs_info);
1880                 if (ret) {
1881                         btrfs_warn(fs_info, "failed to resume dev_replace");
1882                         goto restore;
1883                 }
1884
1885                 btrfs_qgroup_rescan_resume(fs_info);
1886
1887                 if (!fs_info->uuid_root) {
1888                         btrfs_info(fs_info, "creating UUID tree");
1889                         ret = btrfs_create_uuid_tree(fs_info);
1890                         if (ret) {
1891                                 btrfs_warn(fs_info,
1892                                            "failed to create the UUID tree %d",
1893                                            ret);
1894                                 goto restore;
1895                         }
1896                 }
1897                 sb->s_flags &= ~SB_RDONLY;
1898
1899                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1900         }
1901 out:
1902         wake_up_process(fs_info->transaction_kthread);
1903         btrfs_remount_cleanup(fs_info, old_opts);
1904         return 0;
1905
1906 restore:
1907         /* We've hit an error - don't reset SB_RDONLY */
1908         if (sb_rdonly(sb))
1909                 old_flags |= SB_RDONLY;
1910         sb->s_flags = old_flags;
1911         fs_info->mount_opt = old_opts;
1912         fs_info->compress_type = old_compress_type;
1913         fs_info->max_inline = old_max_inline;
1914         btrfs_resize_thread_pool(fs_info,
1915                 old_thread_pool_size, fs_info->thread_pool_size);
1916         fs_info->metadata_ratio = old_metadata_ratio;
1917         btrfs_remount_cleanup(fs_info, old_opts);
1918         return ret;
1919 }
1920
1921 /* Used to sort the devices by max_avail(descending sort) */
1922 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1923                                        const void *dev_info2)
1924 {
1925         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1926             ((struct btrfs_device_info *)dev_info2)->max_avail)
1927                 return -1;
1928         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1929                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1930                 return 1;
1931         else
1932         return 0;
1933 }
1934
1935 /*
1936  * sort the devices by max_avail, in which max free extent size of each device
1937  * is stored.(Descending Sort)
1938  */
1939 static inline void btrfs_descending_sort_devices(
1940                                         struct btrfs_device_info *devices,
1941                                         size_t nr_devices)
1942 {
1943         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1944              btrfs_cmp_device_free_bytes, NULL);
1945 }
1946
1947 /*
1948  * The helper to calc the free space on the devices that can be used to store
1949  * file data.
1950  */
1951 static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1952                                        u64 *free_bytes)
1953 {
1954         struct btrfs_device_info *devices_info;
1955         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1956         struct btrfs_device *device;
1957         u64 skip_space;
1958         u64 type;
1959         u64 avail_space;
1960         u64 min_stripe_size;
1961         int min_stripes = 1, num_stripes = 1;
1962         int i = 0, nr_devices;
1963
1964         /*
1965          * We aren't under the device list lock, so this is racy-ish, but good
1966          * enough for our purposes.
1967          */
1968         nr_devices = fs_info->fs_devices->open_devices;
1969         if (!nr_devices) {
1970                 smp_mb();
1971                 nr_devices = fs_info->fs_devices->open_devices;
1972                 ASSERT(nr_devices);
1973                 if (!nr_devices) {
1974                         *free_bytes = 0;
1975                         return 0;
1976                 }
1977         }
1978
1979         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1980                                GFP_KERNEL);
1981         if (!devices_info)
1982                 return -ENOMEM;
1983
1984         /* calc min stripe number for data space allocation */
1985         type = btrfs_data_alloc_profile(fs_info);
1986         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1987                 min_stripes = 2;
1988                 num_stripes = nr_devices;
1989         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1990                 min_stripes = 2;
1991                 num_stripes = 2;
1992         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1993                 min_stripes = 4;
1994                 num_stripes = 4;
1995         }
1996
1997         if (type & BTRFS_BLOCK_GROUP_DUP)
1998                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1999         else
2000                 min_stripe_size = BTRFS_STRIPE_LEN;
2001
2002         rcu_read_lock();
2003         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
2004                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
2005                                                 &device->dev_state) ||
2006                     !device->bdev ||
2007                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
2008                         continue;
2009
2010                 if (i >= nr_devices)
2011                         break;
2012
2013                 avail_space = device->total_bytes - device->bytes_used;
2014
2015                 /* align with stripe_len */
2016                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
2017                 avail_space *= BTRFS_STRIPE_LEN;
2018
2019                 /*
2020                  * In order to avoid overwriting the superblock on the drive,
2021                  * btrfs starts at an offset of at least 1MB when doing chunk
2022                  * allocation.
2023                  */
2024                 skip_space = SZ_1M;
2025
2026                 /*
2027                  * we can use the free space in [0, skip_space - 1], subtract
2028                  * it from the total.
2029                  */
2030                 if (avail_space && avail_space >= skip_space)
2031                         avail_space -= skip_space;
2032                 else
2033                         avail_space = 0;
2034
2035                 if (avail_space < min_stripe_size)
2036                         continue;
2037
2038                 devices_info[i].dev = device;
2039                 devices_info[i].max_avail = avail_space;
2040
2041                 i++;
2042         }
2043         rcu_read_unlock();
2044
2045         nr_devices = i;
2046
2047         btrfs_descending_sort_devices(devices_info, nr_devices);
2048
2049         i = nr_devices - 1;
2050         avail_space = 0;
2051         while (nr_devices >= min_stripes) {
2052                 if (num_stripes > nr_devices)
2053                         num_stripes = nr_devices;
2054
2055                 if (devices_info[i].max_avail >= min_stripe_size) {
2056                         int j;
2057                         u64 alloc_size;
2058
2059                         avail_space += devices_info[i].max_avail * num_stripes;
2060                         alloc_size = devices_info[i].max_avail;
2061                         for (j = i + 1 - num_stripes; j <= i; j++)
2062                                 devices_info[j].max_avail -= alloc_size;
2063                 }
2064                 i--;
2065                 nr_devices--;
2066         }
2067
2068         kfree(devices_info);
2069         *free_bytes = avail_space;
2070         return 0;
2071 }
2072
2073 /*
2074  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2075  *
2076  * If there's a redundant raid level at DATA block groups, use the respective
2077  * multiplier to scale the sizes.
2078  *
2079  * Unused device space usage is based on simulating the chunk allocator
2080  * algorithm that respects the device sizes and order of allocations.  This is
2081  * a close approximation of the actual use but there are other factors that may
2082  * change the result (like a new metadata chunk).
2083  *
2084  * If metadata is exhausted, f_bavail will be 0.
2085  */
2086 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2087 {
2088         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2089         struct btrfs_super_block *disk_super = fs_info->super_copy;
2090         struct list_head *head = &fs_info->space_info;
2091         struct btrfs_space_info *found;
2092         u64 total_used = 0;
2093         u64 total_free_data = 0;
2094         u64 total_free_meta = 0;
2095         int bits = dentry->d_sb->s_blocksize_bits;
2096         __be32 *fsid = (__be32 *)fs_info->fsid;
2097         unsigned factor = 1;
2098         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2099         int ret;
2100         u64 thresh = 0;
2101         int mixed = 0;
2102
2103         rcu_read_lock();
2104         list_for_each_entry_rcu(found, head, list) {
2105                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2106                         int i;
2107
2108                         total_free_data += found->disk_total - found->disk_used;
2109                         total_free_data -=
2110                                 btrfs_account_ro_block_groups_free_space(found);
2111
2112                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2113                                 if (!list_empty(&found->block_groups[i])) {
2114                                         switch (i) {
2115                                         case BTRFS_RAID_DUP:
2116                                         case BTRFS_RAID_RAID1:
2117                                         case BTRFS_RAID_RAID10:
2118                                                 factor = 2;
2119                                         }
2120                                 }
2121                         }
2122                 }
2123
2124                 /*
2125                  * Metadata in mixed block goup profiles are accounted in data
2126                  */
2127                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2128                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2129                                 mixed = 1;
2130                         else
2131                                 total_free_meta += found->disk_total -
2132                                         found->disk_used;
2133                 }
2134
2135                 total_used += found->disk_used;
2136         }
2137
2138         rcu_read_unlock();
2139
2140         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2141         buf->f_blocks >>= bits;
2142         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2143
2144         /* Account global block reserve as used, it's in logical size already */
2145         spin_lock(&block_rsv->lock);
2146         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2147         if (buf->f_bfree >= block_rsv->size >> bits)
2148                 buf->f_bfree -= block_rsv->size >> bits;
2149         else
2150                 buf->f_bfree = 0;
2151         spin_unlock(&block_rsv->lock);
2152
2153         buf->f_bavail = div_u64(total_free_data, factor);
2154         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2155         if (ret)
2156                 return ret;
2157         buf->f_bavail += div_u64(total_free_data, factor);
2158         buf->f_bavail = buf->f_bavail >> bits;
2159
2160         /*
2161          * We calculate the remaining metadata space minus global reserve. If
2162          * this is (supposedly) smaller than zero, there's no space. But this
2163          * does not hold in practice, the exhausted state happens where's still
2164          * some positive delta. So we apply some guesswork and compare the
2165          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2166          *
2167          * We probably cannot calculate the exact threshold value because this
2168          * depends on the internal reservations requested by various
2169          * operations, so some operations that consume a few metadata will
2170          * succeed even if the Avail is zero. But this is better than the other
2171          * way around.
2172          */
2173         thresh = SZ_4M;
2174
2175         if (!mixed && total_free_meta - thresh < block_rsv->size)
2176                 buf->f_bavail = 0;
2177
2178         buf->f_type = BTRFS_SUPER_MAGIC;
2179         buf->f_bsize = dentry->d_sb->s_blocksize;
2180         buf->f_namelen = BTRFS_NAME_LEN;
2181
2182         /* We treat it as constant endianness (it doesn't matter _which_)
2183            because we want the fsid to come out the same whether mounted
2184            on a big-endian or little-endian host */
2185         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2186         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2187         /* Mask in the root object ID too, to disambiguate subvols */
2188         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2189         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2190
2191         return 0;
2192 }
2193
2194 static void btrfs_kill_super(struct super_block *sb)
2195 {
2196         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2197         kill_anon_super(sb);
2198         free_fs_info(fs_info);
2199 }
2200
2201 static struct file_system_type btrfs_fs_type = {
2202         .owner          = THIS_MODULE,
2203         .name           = "btrfs",
2204         .mount          = btrfs_mount,
2205         .kill_sb        = btrfs_kill_super,
2206         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2207 };
2208
2209 static struct file_system_type btrfs_root_fs_type = {
2210         .owner          = THIS_MODULE,
2211         .name           = "btrfs",
2212         .mount          = btrfs_mount_root,
2213         .kill_sb        = btrfs_kill_super,
2214         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2215 };
2216
2217 MODULE_ALIAS_FS("btrfs");
2218
2219 static int btrfs_control_open(struct inode *inode, struct file *file)
2220 {
2221         /*
2222          * The control file's private_data is used to hold the
2223          * transaction when it is started and is used to keep
2224          * track of whether a transaction is already in progress.
2225          */
2226         file->private_data = NULL;
2227         return 0;
2228 }
2229
2230 /*
2231  * used by btrfsctl to scan devices when no FS is mounted
2232  */
2233 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2234                                 unsigned long arg)
2235 {
2236         struct btrfs_ioctl_vol_args *vol;
2237         struct btrfs_fs_devices *fs_devices;
2238         int ret = -ENOTTY;
2239
2240         if (!capable(CAP_SYS_ADMIN))
2241                 return -EPERM;
2242
2243         vol = memdup_user((void __user *)arg, sizeof(*vol));
2244         if (IS_ERR(vol))
2245                 return PTR_ERR(vol);
2246
2247         switch (cmd) {
2248         case BTRFS_IOC_SCAN_DEV:
2249                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2250                                             &btrfs_root_fs_type, &fs_devices);
2251                 break;
2252         case BTRFS_IOC_DEVICES_READY:
2253                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2254                                             &btrfs_root_fs_type, &fs_devices);
2255                 if (ret)
2256                         break;
2257                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2258                 break;
2259         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2260                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2261                 break;
2262         }
2263
2264         kfree(vol);
2265         return ret;
2266 }
2267
2268 static int btrfs_freeze(struct super_block *sb)
2269 {
2270         struct btrfs_trans_handle *trans;
2271         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2272         struct btrfs_root *root = fs_info->tree_root;
2273
2274         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2275         /*
2276          * We don't need a barrier here, we'll wait for any transaction that
2277          * could be in progress on other threads (and do delayed iputs that
2278          * we want to avoid on a frozen filesystem), or do the commit
2279          * ourselves.
2280          */
2281         trans = btrfs_attach_transaction_barrier(root);
2282         if (IS_ERR(trans)) {
2283                 /* no transaction, don't bother */
2284                 if (PTR_ERR(trans) == -ENOENT)
2285                         return 0;
2286                 return PTR_ERR(trans);
2287         }
2288         return btrfs_commit_transaction(trans);
2289 }
2290
2291 static int btrfs_unfreeze(struct super_block *sb)
2292 {
2293         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2294
2295         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2296         return 0;
2297 }
2298
2299 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2300 {
2301         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2302         struct btrfs_fs_devices *cur_devices;
2303         struct btrfs_device *dev, *first_dev = NULL;
2304         struct list_head *head;
2305         struct rcu_string *name;
2306
2307         /*
2308          * Lightweight locking of the devices. We should not need
2309          * device_list_mutex here as we only read the device data and the list
2310          * is protected by RCU.  Even if a device is deleted during the list
2311          * traversals, we'll get valid data, the freeing callback will wait at
2312          * least until until the rcu_read_unlock.
2313          */
2314         rcu_read_lock();
2315         cur_devices = fs_info->fs_devices;
2316         while (cur_devices) {
2317                 head = &cur_devices->devices;
2318                 list_for_each_entry_rcu(dev, head, dev_list) {
2319                         if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
2320                                 continue;
2321                         if (!dev->name)
2322                                 continue;
2323                         if (!first_dev || dev->devid < first_dev->devid)
2324                                 first_dev = dev;
2325                 }
2326                 cur_devices = cur_devices->seed;
2327         }
2328
2329         if (first_dev) {
2330                 name = rcu_dereference(first_dev->name);
2331                 seq_escape(m, name->str, " \t\n\\");
2332         } else {
2333                 WARN_ON(1);
2334         }
2335         rcu_read_unlock();
2336         return 0;
2337 }
2338
2339 static const struct super_operations btrfs_super_ops = {
2340         .drop_inode     = btrfs_drop_inode,
2341         .evict_inode    = btrfs_evict_inode,
2342         .put_super      = btrfs_put_super,
2343         .sync_fs        = btrfs_sync_fs,
2344         .show_options   = btrfs_show_options,
2345         .show_devname   = btrfs_show_devname,
2346         .write_inode    = btrfs_write_inode,
2347         .alloc_inode    = btrfs_alloc_inode,
2348         .destroy_inode  = btrfs_destroy_inode,
2349         .statfs         = btrfs_statfs,
2350         .remount_fs     = btrfs_remount,
2351         .freeze_fs      = btrfs_freeze,
2352         .unfreeze_fs    = btrfs_unfreeze,
2353 };
2354
2355 static const struct file_operations btrfs_ctl_fops = {
2356         .open = btrfs_control_open,
2357         .unlocked_ioctl  = btrfs_control_ioctl,
2358         .compat_ioctl = btrfs_control_ioctl,
2359         .owner   = THIS_MODULE,
2360         .llseek = noop_llseek,
2361 };
2362
2363 static struct miscdevice btrfs_misc = {
2364         .minor          = BTRFS_MINOR,
2365         .name           = "btrfs-control",
2366         .fops           = &btrfs_ctl_fops
2367 };
2368
2369 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2370 MODULE_ALIAS("devname:btrfs-control");
2371
2372 static int __init btrfs_interface_init(void)
2373 {
2374         return misc_register(&btrfs_misc);
2375 }
2376
2377 static __cold void btrfs_interface_exit(void)
2378 {
2379         misc_deregister(&btrfs_misc);
2380 }
2381
2382 static void __init btrfs_print_mod_info(void)
2383 {
2384         pr_info("Btrfs loaded, crc32c=%s"
2385 #ifdef CONFIG_BTRFS_DEBUG
2386                         ", debug=on"
2387 #endif
2388 #ifdef CONFIG_BTRFS_ASSERT
2389                         ", assert=on"
2390 #endif
2391 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2392                         ", integrity-checker=on"
2393 #endif
2394 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2395                         ", ref-verify=on"
2396 #endif
2397                         "\n",
2398                         crc32c_impl());
2399 }
2400
2401 static int __init init_btrfs_fs(void)
2402 {
2403         int err;
2404
2405         btrfs_props_init();
2406
2407         err = btrfs_init_sysfs();
2408         if (err)
2409                 return err;
2410
2411         btrfs_init_compress();
2412
2413         err = btrfs_init_cachep();
2414         if (err)
2415                 goto free_compress;
2416
2417         err = extent_io_init();
2418         if (err)
2419                 goto free_cachep;
2420
2421         err = extent_map_init();
2422         if (err)
2423                 goto free_extent_io;
2424
2425         err = ordered_data_init();
2426         if (err)
2427                 goto free_extent_map;
2428
2429         err = btrfs_delayed_inode_init();
2430         if (err)
2431                 goto free_ordered_data;
2432
2433         err = btrfs_auto_defrag_init();
2434         if (err)
2435                 goto free_delayed_inode;
2436
2437         err = btrfs_delayed_ref_init();
2438         if (err)
2439                 goto free_auto_defrag;
2440
2441         err = btrfs_prelim_ref_init();
2442         if (err)
2443                 goto free_delayed_ref;
2444
2445         err = btrfs_end_io_wq_init();
2446         if (err)
2447                 goto free_prelim_ref;
2448
2449         err = btrfs_interface_init();
2450         if (err)
2451                 goto free_end_io_wq;
2452
2453         btrfs_init_lockdep();
2454
2455         btrfs_print_mod_info();
2456
2457         err = btrfs_run_sanity_tests();
2458         if (err)
2459                 goto unregister_ioctl;
2460
2461         err = register_filesystem(&btrfs_fs_type);
2462         if (err)
2463                 goto unregister_ioctl;
2464
2465         return 0;
2466
2467 unregister_ioctl:
2468         btrfs_interface_exit();
2469 free_end_io_wq:
2470         btrfs_end_io_wq_exit();
2471 free_prelim_ref:
2472         btrfs_prelim_ref_exit();
2473 free_delayed_ref:
2474         btrfs_delayed_ref_exit();
2475 free_auto_defrag:
2476         btrfs_auto_defrag_exit();
2477 free_delayed_inode:
2478         btrfs_delayed_inode_exit();
2479 free_ordered_data:
2480         ordered_data_exit();
2481 free_extent_map:
2482         extent_map_exit();
2483 free_extent_io:
2484         extent_io_exit();
2485 free_cachep:
2486         btrfs_destroy_cachep();
2487 free_compress:
2488         btrfs_exit_compress();
2489         btrfs_exit_sysfs();
2490
2491         return err;
2492 }
2493
2494 static void __exit exit_btrfs_fs(void)
2495 {
2496         btrfs_destroy_cachep();
2497         btrfs_delayed_ref_exit();
2498         btrfs_auto_defrag_exit();
2499         btrfs_delayed_inode_exit();
2500         btrfs_prelim_ref_exit();
2501         ordered_data_exit();
2502         extent_map_exit();
2503         extent_io_exit();
2504         btrfs_interface_exit();
2505         btrfs_end_io_wq_exit();
2506         unregister_filesystem(&btrfs_fs_type);
2507         btrfs_exit_sysfs();
2508         btrfs_cleanup_fs_uuids();
2509         btrfs_exit_compress();
2510 }
2511
2512 late_initcall(init_btrfs_fs);
2513 module_exit(exit_btrfs_fs)
2514
2515 MODULE_LICENSE("GPL");