fs/btrfs/super.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/fs.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/highmem.h>
  25 #include <linux/time.h>
  26 #include <linux/init.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mount.h>
  31 #include <linux/mpage.h>
  32 #include <linux/swap.h>
  33 #include <linux/writeback.h>
  34 #include <linux/statfs.h>
  35 #include <linux/compat.h>
  36 #include <linux/parser.h>
  37 #include <linux/ctype.h>
  38 #include <linux/namei.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/magic.h>
  41 #include <linux/slab.h>
  42 #include <linux/cleancache.h>
  43 #include <linux/ratelimit.h>
  44 #include <linux/btrfs.h>
  45 #include "delayed-inode.h"
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "hash.h"
  52 #include "props.h"
  53 #include "xattr.h"
  54 #include "volumes.h"
  55 #include "export.h"
  56 #include "compression.h"
  57 #include "rcu-string.h"
  58 #include "dev-replace.h"
  59 #include "free-space-cache.h"
  60 #include "backref.h"
  61 #include "tests/btrfs-tests.h"
  62
  63 #include "qgroup.h"
  64 #define CREATE_TRACE_POINTS
  65 #include <trace/events/btrfs.h>
  66
  67 static const struct super_operations btrfs_super_ops;
  68
  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_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 312         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 313         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 314         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 315         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 316         Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 317         Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 318         Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 319         Opt_skip_balance, Opt_check_integrity,
 320         Opt_check_integrity_including_extent_data,
 321         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 322         Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
 323         Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
 324         Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
 325         Opt_nologreplay, Opt_norecovery,
 326 #ifdef CONFIG_BTRFS_DEBUG
 327         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 328 #endif
 329 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 330         Opt_ref_verify,
 331 #endif
 332         Opt_err,
 333 };
 334
 335 static const match_table_t tokens = {
 336         {Opt_degraded, "degraded"},
 337         {Opt_subvol, "subvol=%s"},
 338         {Opt_subvolid, "subvolid=%s"},
 339         {Opt_device, "device=%s"},
 340         {Opt_nodatasum, "nodatasum"},
 341         {Opt_datasum, "datasum"},
 342         {Opt_nodatacow, "nodatacow"},
 343         {Opt_datacow, "datacow"},
 344         {Opt_nobarrier, "nobarrier"},
 345         {Opt_barrier, "barrier"},
 346         {Opt_max_inline, "max_inline=%s"},
 347         {Opt_alloc_start, "alloc_start=%s"},
 348         {Opt_thread_pool, "thread_pool=%d"},
 349         {Opt_compress, "compress"},
 350         {Opt_compress_type, "compress=%s"},
 351         {Opt_compress_force, "compress-force"},
 352         {Opt_compress_force_type, "compress-force=%s"},
 353         {Opt_ssd, "ssd"},
 354         {Opt_ssd_spread, "ssd_spread"},
 355         {Opt_nossd, "nossd"},
 356         {Opt_acl, "acl"},
 357         {Opt_noacl, "noacl"},
 358         {Opt_notreelog, "notreelog"},
 359         {Opt_treelog, "treelog"},
 360         {Opt_nologreplay, "nologreplay"},
 361         {Opt_norecovery, "norecovery"},
 362         {Opt_flushoncommit, "flushoncommit"},
 363         {Opt_noflushoncommit, "noflushoncommit"},
 364         {Opt_ratio, "metadata_ratio=%d"},
 365         {Opt_discard, "discard"},
 366         {Opt_nodiscard, "nodiscard"},
 367         {Opt_space_cache, "space_cache"},
 368         {Opt_space_cache_version, "space_cache=%s"},
 369         {Opt_clear_cache, "clear_cache"},
 370         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 371         {Opt_enospc_debug, "enospc_debug"},
 372         {Opt_noenospc_debug, "noenospc_debug"},
 373         {Opt_subvolrootid, "subvolrootid=%d"},
 374         {Opt_defrag, "autodefrag"},
 375         {Opt_nodefrag, "noautodefrag"},
 376         {Opt_inode_cache, "inode_cache"},
 377         {Opt_noinode_cache, "noinode_cache"},
 378         {Opt_no_space_cache, "nospace_cache"},
 379         {Opt_recovery, "recovery"}, /* deprecated */
 380         {Opt_usebackuproot, "usebackuproot"},
 381         {Opt_skip_balance, "skip_balance"},
 382         {Opt_check_integrity, "check_int"},
 383         {Opt_check_integrity_including_extent_data, "check_int_data"},
 384         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 385         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 386         {Opt_fatal_errors, "fatal_errors=%s"},
 387         {Opt_commit_interval, "commit=%d"},
 388 #ifdef CONFIG_BTRFS_DEBUG
 389         {Opt_fragment_data, "fragment=data"},
 390         {Opt_fragment_metadata, "fragment=metadata"},
 391         {Opt_fragment_all, "fragment=all"},
 392 #endif
 393 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 394         {Opt_ref_verify, "ref_verify"},
 395 #endif
 396         {Opt_err, NULL},
 397 };
 398
 399 /*
 400  * Regular mount options parser.  Everything that is needed only when
 401  * reading in a new superblock is parsed here.
 402  * XXX JDM: This needs to be cleaned up for remount.
 403  */
 404 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 405                         unsigned long new_flags)
 406 {
 407         substring_t args[MAX_OPT_ARGS];
 408         char *p, *num;
 409         u64 cache_gen;
 410         int intarg;
 411         int ret = 0;
 412         char *compress_type;
 413         bool compress_force = false;
 414         enum btrfs_compression_type saved_compress_type;
 415         bool saved_compress_force;
 416         int no_compress = 0;
 417
 418         cache_gen = btrfs_super_cache_generation(info->super_copy);
 419         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 420                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 421         else if (cache_gen)
 422                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 423
 424         /*
 425          * Even the options are empty, we still need to do extra check
 426          * against new flags
 427          */
 428         if (!options)
 429                 goto check;
 430
 431         while ((p = strsep(&options, ",")) != NULL) {
 432                 int token;
 433                 if (!*p)
 434                         continue;
 435
 436                 token = match_token(p, tokens, args);
 437                 switch (token) {
 438                 case Opt_degraded:
 439                         btrfs_info(info, "allowing degraded mounts");
 440                         btrfs_set_opt(info->mount_opt, DEGRADED);
 441                         break;
 442                 case Opt_subvol:
 443                 case Opt_subvolid:
 444                 case Opt_subvolrootid:
 445                 case Opt_device:
 446                         /*
 447                          * These are parsed by btrfs_parse_subvol_options
 448                          * and btrfs_parse_early_options
 449                          * and can be happily ignored here.
 450                          */
 451                         break;
 452                 case Opt_nodatasum:
 453                         btrfs_set_and_info(info, NODATASUM,
 454                                            "setting nodatasum");
 455                         break;
 456                 case Opt_datasum:
 457                         if (btrfs_test_opt(info, NODATASUM)) {
 458                                 if (btrfs_test_opt(info, NODATACOW))
 459                                         btrfs_info(info,
 460                                                    "setting datasum, datacow enabled");
 461                                 else
 462                                         btrfs_info(info, "setting datasum");
 463                         }
 464                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 465                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 466                         break;
 467                 case Opt_nodatacow:
 468                         if (!btrfs_test_opt(info, NODATACOW)) {
 469                                 if (!btrfs_test_opt(info, COMPRESS) ||
 470                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 471                                         btrfs_info(info,
 472                                                    "setting nodatacow, compression disabled");
 473                                 } else {
 474                                         btrfs_info(info, "setting nodatacow");
 475                                 }
 476                         }
 477                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 478                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 479                         btrfs_set_opt(info->mount_opt, NODATACOW);
 480                         btrfs_set_opt(info->mount_opt, NODATASUM);
 481                         break;
 482                 case Opt_datacow:
 483                         btrfs_clear_and_info(info, NODATACOW,
 484                                              "setting datacow");
 485                         break;
 486                 case Opt_compress_force:
 487                 case Opt_compress_force_type:
 488                         compress_force = true;
 489                         /* Fallthrough */
 490                 case Opt_compress:
 491                 case Opt_compress_type:
 492                         saved_compress_type = btrfs_test_opt(info,
 493                                                              COMPRESS) ?
 494                                 info->compress_type : BTRFS_COMPRESS_NONE;
 495                         saved_compress_force =
 496                                 btrfs_test_opt(info, FORCE_COMPRESS);
 497                         if (token == Opt_compress ||
 498                             token == Opt_compress_force ||
 499                             strncmp(args[0].from, "zlib", 4) == 0) {
 500                                 compress_type = "zlib";
 501
 502                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 503                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 504                                 /*
 505                                  * args[0] contains uninitialized data since
 506                                  * for these tokens we don't expect any
 507                                  * parameter.
 508                                  */
 509                                 if (token != Opt_compress &&
 510                                     token != Opt_compress_force)
 511                                         info->compress_level =
 512                                           btrfs_compress_str2level(args[0].from);
 513                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 514                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 515                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 516                                 no_compress = 0;
 517                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 518                                 compress_type = "lzo";
 519                                 info->compress_type = BTRFS_COMPRESS_LZO;
 520                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 521                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 522                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 523                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 524                                 no_compress = 0;
 525                         } else if (strcmp(args[0].from, "zstd") == 0) {
 526                                 compress_type = "zstd";
 527                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 528                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 529                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 530                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 531                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 532                                 no_compress = 0;
 533                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 534                                 compress_type = "no";
 535                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 536                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 537                                 compress_force = false;
 538                                 no_compress++;
 539                         } else {
 540                                 ret = -EINVAL;
 541                                 goto out;
 542                         }
 543
 544                         if (compress_force) {
 545                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 546                         } else {
 547                                 /*
 548                                  * If we remount from compress-force=xxx to
 549                                  * compress=xxx, we need clear FORCE_COMPRESS
 550                                  * flag, otherwise, there is no way for users
 551                                  * to disable forcible compression separately.
 552                                  */
 553                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 554                         }
 555                         if ((btrfs_test_opt(info, COMPRESS) &&
 556                              (info->compress_type != saved_compress_type ||
 557                               compress_force != saved_compress_force)) ||
 558                             (!btrfs_test_opt(info, COMPRESS) &&
 559                              no_compress == 1)) {
 560                                 btrfs_info(info, "%s %s compression, level %d",
 561                                            (compress_force) ? "force" : "use",
 562                                            compress_type, info->compress_level);
 563                         }
 564                         compress_force = false;
 565                         break;
 566                 case Opt_ssd:
 567                         btrfs_set_and_info(info, SSD,
 568                                            "enabling ssd optimizations");
 569                         btrfs_clear_opt(info->mount_opt, NOSSD);
 570                         break;
 571                 case Opt_ssd_spread:
 572                         btrfs_set_and_info(info, SSD,
 573                                            "enabling ssd optimizations");
 574                         btrfs_set_and_info(info, SSD_SPREAD,
 575                                            "using spread ssd allocation scheme");
 576                         btrfs_clear_opt(info->mount_opt, NOSSD);
 577                         break;
 578                 case Opt_nossd:
 579                         btrfs_set_opt(info->mount_opt, NOSSD);
 580                         btrfs_clear_and_info(info, SSD,
 581                                              "not using ssd optimizations");
 582                         btrfs_clear_and_info(info, SSD_SPREAD,
 583                                              "not using spread ssd allocation scheme");
 584                         break;
 585                 case Opt_barrier:
 586                         btrfs_clear_and_info(info, NOBARRIER,
 587                                              "turning on barriers");
 588                         break;
 589                 case Opt_nobarrier:
 590                         btrfs_set_and_info(info, NOBARRIER,
 591                                            "turning off barriers");
 592                         break;
 593                 case Opt_thread_pool:
 594                         ret = match_int(&args[0], &intarg);
 595                         if (ret) {
 596                                 goto out;
 597                         } else if (intarg > 0) {
 598                                 info->thread_pool_size = intarg;
 599                         } else {
 600                                 ret = -EINVAL;
 601                                 goto out;
 602                         }
 603                         break;
 604                 case Opt_max_inline:
 605                         num = match_strdup(&args[0]);
 606                         if (num) {
 607                                 info->max_inline = memparse(num, NULL);
 608                                 kfree(num);
 609
 610                                 if (info->max_inline) {
 611                                         info->max_inline = min_t(u64,
 612                                                 info->max_inline,
 613                                                 info->sectorsize);
 614                                 }
 615                                 btrfs_info(info, "max_inline at %llu",
 616                                            info->max_inline);
 617                         } else {
 618                                 ret = -ENOMEM;
 619                                 goto out;
 620                         }
 621                         break;
 622                 case Opt_alloc_start:
 623                         btrfs_info(info,
 624                                 "option alloc_start is obsolete, ignored");
 625                         break;
 626                 case Opt_acl:
 627 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 628                         info->sb->s_flags |= SB_POSIXACL;
 629                         break;
 630 #else
 631                         btrfs_err(info, "support for ACL not compiled in!");
 632                         ret = -EINVAL;
 633                         goto out;
 634 #endif
 635                 case Opt_noacl:
 636                         info->sb->s_flags &= ~SB_POSIXACL;
 637                         break;
 638                 case Opt_notreelog:
 639                         btrfs_set_and_info(info, NOTREELOG,
 640                                            "disabling tree log");
 641                         break;
 642                 case Opt_treelog:
 643                         btrfs_clear_and_info(info, NOTREELOG,
 644                                              "enabling tree log");
 645                         break;
 646                 case Opt_norecovery:
 647                 case Opt_nologreplay:
 648                         btrfs_set_and_info(info, NOLOGREPLAY,
 649                                            "disabling log replay at mount time");
 650                         break;
 651                 case Opt_flushoncommit:
 652                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 653                                            "turning on flush-on-commit");
 654                         break;
 655                 case Opt_noflushoncommit:
 656                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 657                                              "turning off flush-on-commit");
 658                         break;
 659                 case Opt_ratio:
 660                         ret = match_int(&args[0], &intarg);
 661                         if (ret) {
 662                                 goto out;
 663                         } else if (intarg >= 0) {
 664                                 info->metadata_ratio = intarg;
 665                                 btrfs_info(info, "metadata ratio %d",
 666                                            info->metadata_ratio);
 667                         } else {
 668                                 ret = -EINVAL;
 669                                 goto out;
 670                         }
 671                         break;
 672                 case Opt_discard:
 673                         btrfs_set_and_info(info, DISCARD,
 674                                            "turning on discard");
 675                         break;
 676                 case Opt_nodiscard:
 677                         btrfs_clear_and_info(info, DISCARD,
 678                                              "turning off discard");
 679                         break;
 680                 case Opt_space_cache:
 681                 case Opt_space_cache_version:
 682                         if (token == Opt_space_cache ||
 683                             strcmp(args[0].from, "v1") == 0) {
 684                                 btrfs_clear_opt(info->mount_opt,
 685                                                 FREE_SPACE_TREE);
 686                                 btrfs_set_and_info(info, SPACE_CACHE,
 687                                            "enabling disk space caching");
 688                         } else if (strcmp(args[0].from, "v2") == 0) {
 689                                 btrfs_clear_opt(info->mount_opt,
 690                                                 SPACE_CACHE);
 691                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 692                                                    "enabling free space tree");
 693                         } else {
 694                                 ret = -EINVAL;
 695                                 goto out;
 696                         }
 697                         break;
 698                 case Opt_rescan_uuid_tree:
 699                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 700                         break;
 701                 case Opt_no_space_cache:
 702                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 703                                 btrfs_clear_and_info(info, SPACE_CACHE,
 704                                              "disabling disk space caching");
 705                         }
 706                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 707                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 708                                              "disabling free space tree");
 709                         }
 710                         break;
 711                 case Opt_inode_cache:
 712                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 713                                            "enabling inode map caching");
 714                         break;
 715                 case Opt_noinode_cache:
 716                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 717                                              "disabling inode map caching");
 718                         break;
 719                 case Opt_clear_cache:
 720                         btrfs_set_and_info(info, CLEAR_CACHE,
 721                                            "force clearing of disk cache");
 722                         break;
 723                 case Opt_user_subvol_rm_allowed:
 724                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 725                         break;
 726                 case Opt_enospc_debug:
 727                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 728                         break;
 729                 case Opt_noenospc_debug:
 730                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 731                         break;
 732                 case Opt_defrag:
 733                         btrfs_set_and_info(info, AUTO_DEFRAG,
 734                                            "enabling auto defrag");
 735                         break;
 736                 case Opt_nodefrag:
 737                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 738                                              "disabling auto defrag");
 739                         break;
 740                 case Opt_recovery:
 741                         btrfs_warn(info,
 742                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 743                 case Opt_usebackuproot:
 744                         btrfs_info(info,
 745                                    "trying to use backup root at mount time");
 746                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 747                         break;
 748                 case Opt_skip_balance:
 749                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 750                         break;
 751 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 752                 case Opt_check_integrity_including_extent_data:
 753                         btrfs_info(info,
 754                                    "enabling check integrity including extent data");
 755                         btrfs_set_opt(info->mount_opt,
 756                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 757                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 758                         break;
 759                 case Opt_check_integrity:
 760                         btrfs_info(info, "enabling check integrity");
 761                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 762                         break;
 763                 case Opt_check_integrity_print_mask:
 764                         ret = match_int(&args[0], &intarg);
 765                         if (ret) {
 766                                 goto out;
 767                         } else if (intarg >= 0) {
 768                                 info->check_integrity_print_mask = intarg;
 769                                 btrfs_info(info,
 770                                            "check_integrity_print_mask 0x%x",
 771                                            info->check_integrity_print_mask);
 772                         } else {
 773                                 ret = -EINVAL;
 774                                 goto out;
 775                         }
 776                         break;
 777 #else
 778                 case Opt_check_integrity_including_extent_data:
 779                 case Opt_check_integrity:
 780                 case Opt_check_integrity_print_mask:
 781                         btrfs_err(info,
 782                                   "support for check_integrity* not compiled in!");
 783                         ret = -EINVAL;
 784                         goto out;
 785 #endif
 786                 case Opt_fatal_errors:
 787                         if (strcmp(args[0].from, "panic") == 0)
 788                                 btrfs_set_opt(info->mount_opt,
 789                                               PANIC_ON_FATAL_ERROR);
 790                         else if (strcmp(args[0].from, "bug") == 0)
 791                                 btrfs_clear_opt(info->mount_opt,
 792                                               PANIC_ON_FATAL_ERROR);
 793                         else {
 794                                 ret = -EINVAL;
 795                                 goto out;
 796                         }
 797                         break;
 798                 case Opt_commit_interval:
 799                         intarg = 0;
 800                         ret = match_int(&args[0], &intarg);
 801                         if (ret < 0) {
 802                                 btrfs_err(info, "invalid commit interval");
 803                                 ret = -EINVAL;
 804                                 goto out;
 805                         }
 806                         if (intarg > 0) {
 807                                 if (intarg > 300) {
 808                                         btrfs_warn(info,
 809                                                 "excessive commit interval %d",
 810                                                 intarg);
 811                                 }
 812                                 info->commit_interval = intarg;
 813                         } else {
 814                                 btrfs_info(info,
 815                                            "using default commit interval %ds",
 816                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 817                                 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 818                         }
 819                         break;
 820 #ifdef CONFIG_BTRFS_DEBUG
 821                 case Opt_fragment_all:
 822                         btrfs_info(info, "fragmenting all space");
 823                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 824                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 825                         break;
 826                 case Opt_fragment_metadata:
 827                         btrfs_info(info, "fragmenting metadata");
 828                         btrfs_set_opt(info->mount_opt,
 829                                       FRAGMENT_METADATA);
 830                         break;
 831                 case Opt_fragment_data:
 832                         btrfs_info(info, "fragmenting data");
 833                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 834                         break;
 835 #endif
 836 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 837                 case Opt_ref_verify:
 838                         btrfs_info(info, "doing ref verification");
 839                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 840                         break;
 841 #endif
 842                 case Opt_err:
 843                         btrfs_info(info, "unrecognized mount option '%s'", p);
 844                         ret = -EINVAL;
 845                         goto out;
 846                 default:
 847                         break;
 848                 }
 849         }
 850 check:
 851         /*
 852          * Extra check for current option against current flag
 853          */
 854         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & SB_RDONLY)) {
 855                 btrfs_err(info,
 856                           "nologreplay must be used with ro mount option");
 857                 ret = -EINVAL;
 858         }
 859 out:
 860         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 861             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 862             !btrfs_test_opt(info, CLEAR_CACHE)) {
 863                 btrfs_err(info, "cannot disable free space tree");
 864                 ret = -EINVAL;
 865
 866         }
 867         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 868                 btrfs_info(info, "disk space caching is enabled");
 869         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 870                 btrfs_info(info, "using free space tree");
 871         return ret;
 872 }
 873
 874 /*
 875  * Parse mount options that are required early in the mount process.
 876  *
 877  * All other options will be parsed on much later in the mount process and
 878  * only when we need to allocate a new super block.
 879  */
 880 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 881                 void *holder, struct btrfs_fs_devices **fs_devices)
 882 {
 883         substring_t args[MAX_OPT_ARGS];
 884         char *device_name, *opts, *orig, *p;
 885         int error = 0;
 886
 887         if (!options)
 888                 return 0;
 889
 890         /*
 891          * strsep changes the string, duplicate it because btrfs_parse_options
 892          * gets called later
 893          */
 894         opts = kstrdup(options, GFP_KERNEL);
 895         if (!opts)
 896                 return -ENOMEM;
 897         orig = opts;
 898
 899         while ((p = strsep(&opts, ",")) != NULL) {
 900                 int token;
 901
 902                 if (!*p)
 903                         continue;
 904
 905                 token = match_token(p, tokens, args);
 906                 if (token == Opt_device) {
 907                         device_name = match_strdup(&args[0]);
 908                         if (!device_name) {
 909                                 error = -ENOMEM;
 910                                 goto out;
 911                         }
 912                         error = btrfs_scan_one_device(device_name,
 913                                         flags, holder, fs_devices);
 914                         kfree(device_name);
 915                         if (error)
 916                                 goto out;
 917                 }
 918         }
 919
 920 out:
 921         kfree(orig);
 922         return error;
 923 }
 924
 925 /*
 926  * Parse mount options that are related to subvolume id
 927  *
 928  * The value is later passed to mount_subvol()
 929  */
 930 static int btrfs_parse_subvol_options(const char *options, fmode_t flags,
 931                 char **subvol_name, u64 *subvol_objectid)
 932 {
 933         substring_t args[MAX_OPT_ARGS];
 934         char *opts, *orig, *p;
 935         char *num = NULL;
 936         int error = 0;
 937
 938         if (!options)
 939                 return 0;
 940
 941         /*
 942          * strsep changes the string, duplicate it because
 943          * btrfs_parse_early_options gets called later
 944          */
 945         opts = kstrdup(options, GFP_KERNEL);
 946         if (!opts)
 947                 return -ENOMEM;
 948         orig = opts;
 949
 950         while ((p = strsep(&opts, ",")) != NULL) {
 951                 int token;
 952                 if (!*p)
 953                         continue;
 954
 955                 token = match_token(p, tokens, args);
 956                 switch (token) {
 957                 case Opt_subvol:
 958                         kfree(*subvol_name);
 959                         *subvol_name = match_strdup(&args[0]);
 960                         if (!*subvol_name) {
 961                                 error = -ENOMEM;
 962                                 goto out;
 963                         }
 964                         break;
 965                 case Opt_subvolid:
 966                         num = match_strdup(&args[0]);
 967                         if (num) {
 968                                 *subvol_objectid = memparse(num, NULL);
 969                                 kfree(num);
 970                                 /* we want the original fs_tree */
 971                                 if (!*subvol_objectid)
 972                                         *subvol_objectid =
 973                                                 BTRFS_FS_TREE_OBJECTID;
 974                         } else {
 975                                 error = -EINVAL;
 976                                 goto out;
 977                         }
 978                         break;
 979                 case Opt_subvolrootid:
 980                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
 981                         break;
 982                 default:
 983                         break;
 984                 }
 985         }
 986
 987 out:
 988         kfree(orig);
 989         return error;
 990 }
 991
 992 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 993                                            u64 subvol_objectid)
 994 {
 995         struct btrfs_root *root = fs_info->tree_root;
 996         struct btrfs_root *fs_root;
 997         struct btrfs_root_ref *root_ref;
 998         struct btrfs_inode_ref *inode_ref;
 999         struct btrfs_key key;
1000         struct btrfs_path *path = NULL;
1001         char *name = NULL, *ptr;
1002         u64 dirid;
1003         int len;
1004         int ret;
1005
1006         path = btrfs_alloc_path();
1007         if (!path) {
1008                 ret = -ENOMEM;
1009                 goto err;
1010         }
1011         path->leave_spinning = 1;
1012
1013         name = kmalloc(PATH_MAX, GFP_KERNEL);
1014         if (!name) {
1015                 ret = -ENOMEM;
1016                 goto err;
1017         }
1018         ptr = name + PATH_MAX - 1;
1019         ptr[0] = '\0';
1020
1021         /*
1022          * Walk up the subvolume trees in the tree of tree roots by root
1023          * backrefs until we hit the top-level subvolume.
1024          */
1025         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1026                 key.objectid = subvol_objectid;
1027                 key.type = BTRFS_ROOT_BACKREF_KEY;
1028                 key.offset = (u64)-1;
1029
1030                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1031                 if (ret < 0) {
1032                         goto err;
1033                 } else if (ret > 0) {
1034                         ret = btrfs_previous_item(root, path, subvol_objectid,
1035                                                   BTRFS_ROOT_BACKREF_KEY);
1036                         if (ret < 0) {
1037                                 goto err;
1038                         } else if (ret > 0) {
1039                                 ret = -ENOENT;
1040                                 goto err;
1041                         }
1042                 }
1043
1044                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1045                 subvol_objectid = key.offset;
1046
1047                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1048                                           struct btrfs_root_ref);
1049                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1050                 ptr -= len + 1;
1051                 if (ptr < name) {
1052                         ret = -ENAMETOOLONG;
1053                         goto err;
1054                 }
1055                 read_extent_buffer(path->nodes[0], ptr + 1,
1056                                    (unsigned long)(root_ref + 1), len);
1057                 ptr[0] = '/';
1058                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1059                 btrfs_release_path(path);
1060
1061                 key.objectid = subvol_objectid;
1062                 key.type = BTRFS_ROOT_ITEM_KEY;
1063                 key.offset = (u64)-1;
1064                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1065                 if (IS_ERR(fs_root)) {
1066                         ret = PTR_ERR(fs_root);
1067                         goto err;
1068                 }
1069
1070                 /*
1071                  * Walk up the filesystem tree by inode refs until we hit the
1072                  * root directory.
1073                  */
1074                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1075                         key.objectid = dirid;
1076                         key.type = BTRFS_INODE_REF_KEY;
1077                         key.offset = (u64)-1;
1078
1079                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1080                         if (ret < 0) {
1081                                 goto err;
1082                         } else if (ret > 0) {
1083                                 ret = btrfs_previous_item(fs_root, path, dirid,
1084                                                           BTRFS_INODE_REF_KEY);
1085                                 if (ret < 0) {
1086                                         goto err;
1087                                 } else if (ret > 0) {
1088                                         ret = -ENOENT;
1089                                         goto err;
1090                                 }
1091                         }
1092
1093                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1094                         dirid = key.offset;
1095
1096                         inode_ref = btrfs_item_ptr(path->nodes[0],
1097                                                    path->slots[0],
1098                                                    struct btrfs_inode_ref);
1099                         len = btrfs_inode_ref_name_len(path->nodes[0],
1100                                                        inode_ref);
1101                         ptr -= len + 1;
1102                         if (ptr < name) {
1103                                 ret = -ENAMETOOLONG;
1104                                 goto err;
1105                         }
1106                         read_extent_buffer(path->nodes[0], ptr + 1,
1107                                            (unsigned long)(inode_ref + 1), len);
1108                         ptr[0] = '/';
1109                         btrfs_release_path(path);
1110                 }
1111         }
1112
1113         btrfs_free_path(path);
1114         if (ptr == name + PATH_MAX - 1) {
1115                 name[0] = '/';
1116                 name[1] = '\0';
1117         } else {
1118                 memmove(name, ptr, name + PATH_MAX - ptr);
1119         }
1120         return name;
1121
1122 err:
1123         btrfs_free_path(path);
1124         kfree(name);
1125         return ERR_PTR(ret);
1126 }
1127
1128 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1129 {
1130         struct btrfs_root *root = fs_info->tree_root;
1131         struct btrfs_dir_item *di;
1132         struct btrfs_path *path;
1133         struct btrfs_key location;
1134         u64 dir_id;
1135
1136         path = btrfs_alloc_path();
1137         if (!path)
1138                 return -ENOMEM;
1139         path->leave_spinning = 1;
1140
1141         /*
1142          * Find the "default" dir item which points to the root item that we
1143          * will mount by default if we haven't been given a specific subvolume
1144          * to mount.
1145          */
1146         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1147         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1148         if (IS_ERR(di)) {
1149                 btrfs_free_path(path);
1150                 return PTR_ERR(di);
1151         }
1152         if (!di) {
1153                 /*
1154                  * Ok the default dir item isn't there.  This is weird since
1155                  * it's always been there, but don't freak out, just try and
1156                  * mount the top-level subvolume.
1157                  */
1158                 btrfs_free_path(path);
1159                 *objectid = BTRFS_FS_TREE_OBJECTID;
1160                 return 0;
1161         }
1162
1163         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1164         btrfs_free_path(path);
1165         *objectid = location.objectid;
1166         return 0;
1167 }
1168
1169 static int btrfs_fill_super(struct super_block *sb,
1170                             struct btrfs_fs_devices *fs_devices,
1171                             void *data)
1172 {
1173         struct inode *inode;
1174         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1175         struct btrfs_key key;
1176         int err;
1177
1178         sb->s_maxbytes = MAX_LFS_FILESIZE;
1179         sb->s_magic = BTRFS_SUPER_MAGIC;
1180         sb->s_op = &btrfs_super_ops;
1181         sb->s_d_op = &btrfs_dentry_operations;
1182         sb->s_export_op = &btrfs_export_ops;
1183         sb->s_xattr = btrfs_xattr_handlers;
1184         sb->s_time_gran = 1;
1185 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1186         sb->s_flags |= SB_POSIXACL;
1187 #endif
1188         sb->s_flags |= SB_I_VERSION;
1189         sb->s_iflags |= SB_I_CGROUPWB;
1190
1191         err = super_setup_bdi(sb);
1192         if (err) {
1193                 btrfs_err(fs_info, "super_setup_bdi failed");
1194                 return err;
1195         }
1196
1197         err = open_ctree(sb, fs_devices, (char *)data);
1198         if (err) {
1199                 btrfs_err(fs_info, "open_ctree failed");
1200                 return err;
1201         }
1202
1203         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1204         key.type = BTRFS_INODE_ITEM_KEY;
1205         key.offset = 0;
1206         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1207         if (IS_ERR(inode)) {
1208                 err = PTR_ERR(inode);
1209                 goto fail_close;
1210         }
1211
1212         sb->s_root = d_make_root(inode);
1213         if (!sb->s_root) {
1214                 err = -ENOMEM;
1215                 goto fail_close;
1216         }
1217
1218         cleancache_init_fs(sb);
1219         sb->s_flags |= SB_ACTIVE;
1220         return 0;
1221
1222 fail_close:
1223         close_ctree(fs_info);
1224         return err;
1225 }
1226
1227 int btrfs_sync_fs(struct super_block *sb, int wait)
1228 {
1229         struct btrfs_trans_handle *trans;
1230         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1231         struct btrfs_root *root = fs_info->tree_root;
1232
1233         trace_btrfs_sync_fs(fs_info, wait);
1234
1235         if (!wait) {
1236                 filemap_flush(fs_info->btree_inode->i_mapping);
1237                 return 0;
1238         }
1239
1240         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1241
1242         trans = btrfs_attach_transaction_barrier(root);
1243         if (IS_ERR(trans)) {
1244                 /* no transaction, don't bother */
1245                 if (PTR_ERR(trans) == -ENOENT) {
1246                         /*
1247                          * Exit unless we have some pending changes
1248                          * that need to go through commit
1249                          */
1250                         if (fs_info->pending_changes == 0)
1251                                 return 0;
1252                         /*
1253                          * A non-blocking test if the fs is frozen. We must not
1254                          * start a new transaction here otherwise a deadlock
1255                          * happens. The pending operations are delayed to the
1256                          * next commit after thawing.
1257                          */
1258                         if (sb_start_write_trylock(sb))
1259                                 sb_end_write(sb);
1260                         else
1261                                 return 0;
1262                         trans = btrfs_start_transaction(root, 0);
1263                 }
1264                 if (IS_ERR(trans))
1265                         return PTR_ERR(trans);
1266         }
1267         return btrfs_commit_transaction(trans);
1268 }
1269
1270 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1271 {
1272         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1273         const char *compress_type;
1274
1275         if (btrfs_test_opt(info, DEGRADED))
1276                 seq_puts(seq, ",degraded");
1277         if (btrfs_test_opt(info, NODATASUM))
1278                 seq_puts(seq, ",nodatasum");
1279         if (btrfs_test_opt(info, NODATACOW))
1280                 seq_puts(seq, ",nodatacow");
1281         if (btrfs_test_opt(info, NOBARRIER))
1282                 seq_puts(seq, ",nobarrier");
1283         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1284                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1285         if (info->thread_pool_size !=  min_t(unsigned long,
1286                                              num_online_cpus() + 2, 8))
1287                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1288         if (btrfs_test_opt(info, COMPRESS)) {
1289                 compress_type = btrfs_compress_type2str(info->compress_type);
1290                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1291                         seq_printf(seq, ",compress-force=%s", compress_type);
1292                 else
1293                         seq_printf(seq, ",compress=%s", compress_type);
1294                 if (info->compress_level)
1295                         seq_printf(seq, ":%d", info->compress_level);
1296         }
1297         if (btrfs_test_opt(info, NOSSD))
1298                 seq_puts(seq, ",nossd");
1299         if (btrfs_test_opt(info, SSD_SPREAD))
1300                 seq_puts(seq, ",ssd_spread");
1301         else if (btrfs_test_opt(info, SSD))
1302                 seq_puts(seq, ",ssd");
1303         if (btrfs_test_opt(info, NOTREELOG))
1304                 seq_puts(seq, ",notreelog");
1305         if (btrfs_test_opt(info, NOLOGREPLAY))
1306                 seq_puts(seq, ",nologreplay");
1307         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1308                 seq_puts(seq, ",flushoncommit");
1309         if (btrfs_test_opt(info, DISCARD))
1310                 seq_puts(seq, ",discard");
1311         if (!(info->sb->s_flags & SB_POSIXACL))
1312                 seq_puts(seq, ",noacl");
1313         if (btrfs_test_opt(info, SPACE_CACHE))
1314                 seq_puts(seq, ",space_cache");
1315         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1316                 seq_puts(seq, ",space_cache=v2");
1317         else
1318                 seq_puts(seq, ",nospace_cache");
1319         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1320                 seq_puts(seq, ",rescan_uuid_tree");
1321         if (btrfs_test_opt(info, CLEAR_CACHE))
1322                 seq_puts(seq, ",clear_cache");
1323         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1324                 seq_puts(seq, ",user_subvol_rm_allowed");
1325         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1326                 seq_puts(seq, ",enospc_debug");
1327         if (btrfs_test_opt(info, AUTO_DEFRAG))
1328                 seq_puts(seq, ",autodefrag");
1329         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1330                 seq_puts(seq, ",inode_cache");
1331         if (btrfs_test_opt(info, SKIP_BALANCE))
1332                 seq_puts(seq, ",skip_balance");
1333 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1334         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1335                 seq_puts(seq, ",check_int_data");
1336         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1337                 seq_puts(seq, ",check_int");
1338         if (info->check_integrity_print_mask)
1339                 seq_printf(seq, ",check_int_print_mask=%d",
1340                                 info->check_integrity_print_mask);
1341 #endif
1342         if (info->metadata_ratio)
1343                 seq_printf(seq, ",metadata_ratio=%d",
1344                                 info->metadata_ratio);
1345         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1346                 seq_puts(seq, ",fatal_errors=panic");
1347         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1348                 seq_printf(seq, ",commit=%d", info->commit_interval);
1349 #ifdef CONFIG_BTRFS_DEBUG
1350         if (btrfs_test_opt(info, FRAGMENT_DATA))
1351                 seq_puts(seq, ",fragment=data");
1352         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1353                 seq_puts(seq, ",fragment=metadata");
1354 #endif
1355         if (btrfs_test_opt(info, REF_VERIFY))
1356                 seq_puts(seq, ",ref_verify");
1357         seq_printf(seq, ",subvolid=%llu",
1358                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1359         seq_puts(seq, ",subvol=");
1360         seq_dentry(seq, dentry, " \t\n\\");
1361         return 0;
1362 }
1363
1364 static int btrfs_test_super(struct super_block *s, void *data)
1365 {
1366         struct btrfs_fs_info *p = data;
1367         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1368
1369         return fs_info->fs_devices == p->fs_devices;
1370 }
1371
1372 static int btrfs_set_super(struct super_block *s, void *data)
1373 {
1374         int err = set_anon_super(s, data);
1375         if (!err)
1376                 s->s_fs_info = data;
1377         return err;
1378 }
1379
1380 /*
1381  * subvolumes are identified by ino 256
1382  */
1383 static inline int is_subvolume_inode(struct inode *inode)
1384 {
1385         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1386                 return 1;
1387         return 0;
1388 }
1389
1390 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1391                                    const char *device_name, struct vfsmount *mnt)
1392 {
1393         struct dentry *root;
1394         int ret;
1395
1396         if (!subvol_name) {
1397                 if (!subvol_objectid) {
1398                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1399                                                           &subvol_objectid);
1400                         if (ret) {
1401                                 root = ERR_PTR(ret);
1402                                 goto out;
1403                         }
1404                 }
1405                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1406                                                             subvol_objectid);
1407                 if (IS_ERR(subvol_name)) {
1408                         root = ERR_CAST(subvol_name);
1409                         subvol_name = NULL;
1410                         goto out;
1411                 }
1412
1413         }
1414
1415         root = mount_subtree(mnt, subvol_name);
1416         /* mount_subtree() drops our reference on the vfsmount. */
1417         mnt = NULL;
1418
1419         if (!IS_ERR(root)) {
1420                 struct super_block *s = root->d_sb;
1421                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1422                 struct inode *root_inode = d_inode(root);
1423                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1424
1425                 ret = 0;
1426                 if (!is_subvolume_inode(root_inode)) {
1427                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1428                                subvol_name);
1429                         ret = -EINVAL;
1430                 }
1431                 if (subvol_objectid && root_objectid != subvol_objectid) {
1432                         /*
1433                          * This will also catch a race condition where a
1434                          * subvolume which was passed by ID is renamed and
1435                          * another subvolume is renamed over the old location.
1436                          */
1437                         btrfs_err(fs_info,
1438                                   "subvol '%s' does not match subvolid %llu",
1439                                   subvol_name, subvol_objectid);
1440                         ret = -EINVAL;
1441                 }
1442                 if (ret) {
1443                         dput(root);
1444                         root = ERR_PTR(ret);
1445                         deactivate_locked_super(s);
1446                 }
1447         }
1448
1449 out:
1450         mntput(mnt);
1451         kfree(subvol_name);
1452         return root;
1453 }
1454
1455 static int parse_security_options(char *orig_opts,
1456                                   struct security_mnt_opts *sec_opts)
1457 {
1458         char *secdata = NULL;
1459         int ret = 0;
1460
1461         secdata = alloc_secdata();
1462         if (!secdata)
1463                 return -ENOMEM;
1464         ret = security_sb_copy_data(orig_opts, secdata);
1465         if (ret) {
1466                 free_secdata(secdata);
1467                 return ret;
1468         }
1469         ret = security_sb_parse_opts_str(secdata, sec_opts);
1470         free_secdata(secdata);
1471         return ret;
1472 }
1473
1474 static int setup_security_options(struct btrfs_fs_info *fs_info,
1475                                   struct super_block *sb,
1476                                   struct security_mnt_opts *sec_opts)
1477 {
1478         int ret = 0;
1479
1480         /*
1481          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1482          * is valid.
1483          */
1484         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1485         if (ret)
1486                 return ret;
1487
1488 #ifdef CONFIG_SECURITY
1489         if (!fs_info->security_opts.num_mnt_opts) {
1490                 /* first time security setup, copy sec_opts to fs_info */
1491                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1492         } else {
1493                 /*
1494                  * Since SELinux (the only one supporting security_mnt_opts)
1495                  * does NOT support changing context during remount/mount of
1496                  * the same sb, this must be the same or part of the same
1497                  * security options, just free it.
1498                  */
1499                 security_free_mnt_opts(sec_opts);
1500         }
1501 #endif
1502         return ret;
1503 }
1504
1505 /*
1506  * Find a superblock for the given device / mount point.
1507  *
1508  * Note: This is based on mount_bdev from fs/super.c with a few additions
1509  *       for multiple device setup.  Make sure to keep it in sync.
1510  */
1511 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1512                 int flags, const char *device_name, void *data)
1513 {
1514         struct block_device *bdev = NULL;
1515         struct super_block *s;
1516         struct btrfs_fs_devices *fs_devices = NULL;
1517         struct btrfs_fs_info *fs_info = NULL;
1518         struct security_mnt_opts new_sec_opts;
1519         fmode_t mode = FMODE_READ;
1520         int error = 0;
1521
1522         if (!(flags & SB_RDONLY))
1523                 mode |= FMODE_WRITE;
1524
1525         error = btrfs_parse_early_options(data, mode, fs_type,
1526                                           &fs_devices);
1527         if (error) {
1528                 return ERR_PTR(error);
1529         }
1530
1531         security_init_mnt_opts(&new_sec_opts);
1532         if (data) {
1533                 error = parse_security_options(data, &new_sec_opts);
1534                 if (error)
1535                         return ERR_PTR(error);
1536         }
1537
1538         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1539         if (error)
1540                 goto error_sec_opts;
1541
1542         /*
1543          * Setup a dummy root and fs_info for test/set super.  This is because
1544          * we don't actually fill this stuff out until open_ctree, but we need
1545          * it for searching for existing supers, so this lets us do that and
1546          * then open_ctree will properly initialize everything later.
1547          */
1548         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1549         if (!fs_info) {
1550                 error = -ENOMEM;
1551                 goto error_sec_opts;
1552         }
1553
1554         fs_info->fs_devices = fs_devices;
1555
1556         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1557         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1558         security_init_mnt_opts(&fs_info->security_opts);
1559         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1560                 error = -ENOMEM;
1561                 goto error_fs_info;
1562         }
1563
1564         error = btrfs_open_devices(fs_devices, mode, fs_type);
1565         if (error)
1566                 goto error_fs_info;
1567
1568         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1569                 error = -EACCES;
1570                 goto error_close_devices;
1571         }
1572
1573         bdev = fs_devices->latest_bdev;
1574         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1575                  fs_info);
1576         if (IS_ERR(s)) {
1577                 error = PTR_ERR(s);
1578                 goto error_close_devices;
1579         }
1580
1581         if (s->s_root) {
1582                 btrfs_close_devices(fs_devices);
1583                 free_fs_info(fs_info);
1584                 if ((flags ^ s->s_flags) & SB_RDONLY)
1585                         error = -EBUSY;
1586         } else {
1587                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1588                 btrfs_sb(s)->bdev_holder = fs_type;
1589                 error = btrfs_fill_super(s, fs_devices, data);
1590         }
1591         if (error) {
1592                 deactivate_locked_super(s);
1593                 goto error_sec_opts;
1594         }
1595
1596         fs_info = btrfs_sb(s);
1597         error = setup_security_options(fs_info, s, &new_sec_opts);
1598         if (error) {
1599                 deactivate_locked_super(s);
1600                 goto error_sec_opts;
1601         }
1602
1603         return dget(s->s_root);
1604
1605 error_close_devices:
1606         btrfs_close_devices(fs_devices);
1607 error_fs_info:
1608         free_fs_info(fs_info);
1609 error_sec_opts:
1610         security_free_mnt_opts(&new_sec_opts);
1611         return ERR_PTR(error);
1612 }
1613
1614 /*
1615  * Mount function which is called by VFS layer.
1616  *
1617  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1618  * which needs vfsmount* of device's root (/).  This means device's root has to
1619  * be mounted internally in any case.
1620  *
1621  * Operation flow:
1622  *   1. Parse subvol id related options for later use in mount_subvol().
1623  *
1624  *   2. Mount device's root (/) by calling vfs_kern_mount().
1625  *
1626  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1627  *      first place. In order to avoid calling btrfs_mount() again, we use
1628  *      different file_system_type which is not registered to VFS by
1629  *      register_filesystem() (btrfs_root_fs_type). As a result,
1630  *      btrfs_mount_root() is called. The return value will be used by
1631  *      mount_subtree() in mount_subvol().
1632  *
1633  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1634  *      "btrfs subvolume set-default", mount_subvol() is called always.
1635  */
1636 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1637                 const char *device_name, void *data)
1638 {
1639         struct vfsmount *mnt_root;
1640         struct dentry *root;
1641         fmode_t mode = FMODE_READ;
1642         char *subvol_name = NULL;
1643         u64 subvol_objectid = 0;
1644         int error = 0;
1645
1646         if (!(flags & SB_RDONLY))
1647                 mode |= FMODE_WRITE;
1648
1649         error = btrfs_parse_subvol_options(data, mode,
1650                                           &subvol_name, &subvol_objectid);
1651         if (error) {
1652                 kfree(subvol_name);
1653                 return ERR_PTR(error);
1654         }
1655
1656         /* mount device's root (/) */
1657         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1658         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1659                 if (flags & SB_RDONLY) {
1660                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1661                                 flags & ~SB_RDONLY, device_name, data);
1662                 } else {
1663                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1664                                 flags | SB_RDONLY, device_name, data);
1665                         if (IS_ERR(mnt_root)) {
1666                                 root = ERR_CAST(mnt_root);
1667                                 goto out;
1668                         }
1669
1670                         down_write(&mnt_root->mnt_sb->s_umount);
1671                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1672                         up_write(&mnt_root->mnt_sb->s_umount);
1673                         if (error < 0) {
1674                                 root = ERR_PTR(error);
1675                                 mntput(mnt_root);
1676                                 goto out;
1677                         }
1678                 }
1679         }
1680         if (IS_ERR(mnt_root)) {
1681                 root = ERR_CAST(mnt_root);
1682                 goto out;
1683         }
1684
1685         /* mount_subvol() will free subvol_name and mnt_root */
1686         root = mount_subvol(subvol_name, subvol_objectid, device_name, mnt_root);
1687
1688 out:
1689         return root;
1690 }
1691
1692 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1693                                      int new_pool_size, int old_pool_size)
1694 {
1695         if (new_pool_size == old_pool_size)
1696                 return;
1697
1698         fs_info->thread_pool_size = new_pool_size;
1699
1700         btrfs_info(fs_info, "resize thread pool %d -> %d",
1701                old_pool_size, new_pool_size);
1702
1703         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1704         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1705         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1706         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1707         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1708         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1709         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1710                                 new_pool_size);
1711         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1712         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1713         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1714         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1715         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1716                                 new_pool_size);
1717 }
1718
1719 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1720 {
1721         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1722 }
1723
1724 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1725                                        unsigned long old_opts, int flags)
1726 {
1727         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1728             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1729              (flags & SB_RDONLY))) {
1730                 /* wait for any defraggers to finish */
1731                 wait_event(fs_info->transaction_wait,
1732                            (atomic_read(&fs_info->defrag_running) == 0));
1733                 if (flags & SB_RDONLY)
1734                         sync_filesystem(fs_info->sb);
1735         }
1736 }
1737
1738 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1739                                          unsigned long old_opts)
1740 {
1741         /*
1742          * We need to cleanup all defragable inodes if the autodefragment is
1743          * close or the filesystem is read only.
1744          */
1745         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1746             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1747                 btrfs_cleanup_defrag_inodes(fs_info);
1748         }
1749
1750         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1751 }
1752
1753 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1754 {
1755         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1756         struct btrfs_root *root = fs_info->tree_root;
1757         unsigned old_flags = sb->s_flags;
1758         unsigned long old_opts = fs_info->mount_opt;
1759         unsigned long old_compress_type = fs_info->compress_type;
1760         u64 old_max_inline = fs_info->max_inline;
1761         int old_thread_pool_size = fs_info->thread_pool_size;
1762         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1763         int ret;
1764
1765         sync_filesystem(sb);
1766         btrfs_remount_prepare(fs_info);
1767
1768         if (data) {
1769                 struct security_mnt_opts new_sec_opts;
1770
1771                 security_init_mnt_opts(&new_sec_opts);
1772                 ret = parse_security_options(data, &new_sec_opts);
1773                 if (ret)
1774                         goto restore;
1775                 ret = setup_security_options(fs_info, sb,
1776                                              &new_sec_opts);
1777                 if (ret) {
1778                         security_free_mnt_opts(&new_sec_opts);
1779                         goto restore;
1780                 }
1781         }
1782
1783         ret = btrfs_parse_options(fs_info, data, *flags);
1784         if (ret) {
1785                 ret = -EINVAL;
1786                 goto restore;
1787         }
1788
1789         btrfs_remount_begin(fs_info, old_opts, *flags);
1790         btrfs_resize_thread_pool(fs_info,
1791                 fs_info->thread_pool_size, old_thread_pool_size);
1792
1793         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1794                 goto out;
1795
1796         if (*flags & SB_RDONLY) {
1797                 /*
1798                  * this also happens on 'umount -rf' or on shutdown, when
1799                  * the filesystem is busy.
1800                  */
1801                 cancel_work_sync(&fs_info->async_reclaim_work);
1802
1803                 /* wait for the uuid_scan task to finish */
1804                 down(&fs_info->uuid_tree_rescan_sem);
1805                 /* avoid complains from lockdep et al. */
1806                 up(&fs_info->uuid_tree_rescan_sem);
1807
1808                 sb->s_flags |= SB_RDONLY;
1809
1810                 /*
1811                  * Setting SB_RDONLY will put the cleaner thread to
1812                  * sleep at the next loop if it's already active.
1813                  * If it's already asleep, we'll leave unused block
1814                  * groups on disk until we're mounted read-write again
1815                  * unless we clean them up here.
1816                  */
1817                 btrfs_delete_unused_bgs(fs_info);
1818
1819                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1820                 btrfs_scrub_cancel(fs_info);
1821                 btrfs_pause_balance(fs_info);
1822
1823                 ret = btrfs_commit_super(fs_info);
1824                 if (ret)
1825                         goto restore;
1826         } else {
1827                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1828                         btrfs_err(fs_info,
1829                                 "Remounting read-write after error is not allowed");
1830                         ret = -EINVAL;
1831                         goto restore;
1832                 }
1833                 if (fs_info->fs_devices->rw_devices == 0) {
1834                         ret = -EACCES;
1835                         goto restore;
1836                 }
1837
1838                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1839                         btrfs_warn(fs_info,
1840                                 "too many missing devices, writeable remount is not allowed");
1841                         ret = -EACCES;
1842                         goto restore;
1843                 }
1844
1845                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1846                         ret = -EINVAL;
1847                         goto restore;
1848                 }
1849
1850                 ret = btrfs_cleanup_fs_roots(fs_info);
1851                 if (ret)
1852                         goto restore;
1853
1854                 /* recover relocation */
1855                 mutex_lock(&fs_info->cleaner_mutex);
1856                 ret = btrfs_recover_relocation(root);
1857                 mutex_unlock(&fs_info->cleaner_mutex);
1858                 if (ret)
1859                         goto restore;
1860
1861                 ret = btrfs_resume_balance_async(fs_info);
1862                 if (ret)
1863                         goto restore;
1864
1865                 ret = btrfs_resume_dev_replace_async(fs_info);
1866                 if (ret) {
1867                         btrfs_warn(fs_info, "failed to resume dev_replace");
1868                         goto restore;
1869                 }
1870
1871                 btrfs_qgroup_rescan_resume(fs_info);
1872
1873                 if (!fs_info->uuid_root) {
1874                         btrfs_info(fs_info, "creating UUID tree");
1875                         ret = btrfs_create_uuid_tree(fs_info);
1876                         if (ret) {
1877                                 btrfs_warn(fs_info,
1878                                            "failed to create the UUID tree %d",
1879                                            ret);
1880                                 goto restore;
1881                         }
1882                 }
1883                 sb->s_flags &= ~SB_RDONLY;
1884
1885                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1886         }
1887 out:
1888         wake_up_process(fs_info->transaction_kthread);
1889         btrfs_remount_cleanup(fs_info, old_opts);
1890         return 0;
1891
1892 restore:
1893         /* We've hit an error - don't reset SB_RDONLY */
1894         if (sb_rdonly(sb))
1895                 old_flags |= SB_RDONLY;
1896         sb->s_flags = old_flags;
1897         fs_info->mount_opt = old_opts;
1898         fs_info->compress_type = old_compress_type;
1899         fs_info->max_inline = old_max_inline;
1900         btrfs_resize_thread_pool(fs_info,
1901                 old_thread_pool_size, fs_info->thread_pool_size);
1902         fs_info->metadata_ratio = old_metadata_ratio;
1903         btrfs_remount_cleanup(fs_info, old_opts);
1904         return ret;
1905 }
1906
1907 /* Used to sort the devices by max_avail(descending sort) */
1908 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1909                                        const void *dev_info2)
1910 {
1911         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1912             ((struct btrfs_device_info *)dev_info2)->max_avail)
1913                 return -1;
1914         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1915                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1916                 return 1;
1917         else
1918         return 0;
1919 }
1920
1921 /*
1922  * sort the devices by max_avail, in which max free extent size of each device
1923  * is stored.(Descending Sort)
1924  */
1925 static inline void btrfs_descending_sort_devices(
1926                                         struct btrfs_device_info *devices,
1927                                         size_t nr_devices)
1928 {
1929         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1930              btrfs_cmp_device_free_bytes, NULL);
1931 }
1932
1933 /*
1934  * The helper to calc the free space on the devices that can be used to store
1935  * file data.
1936  */
1937 static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1938                                        u64 *free_bytes)
1939 {
1940         struct btrfs_device_info *devices_info;
1941         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1942         struct btrfs_device *device;
1943         u64 skip_space;
1944         u64 type;
1945         u64 avail_space;
1946         u64 min_stripe_size;
1947         int min_stripes = 1, num_stripes = 1;
1948         int i = 0, nr_devices;
1949
1950         /*
1951          * We aren't under the device list lock, so this is racy-ish, but good
1952          * enough for our purposes.
1953          */
1954         nr_devices = fs_info->fs_devices->open_devices;
1955         if (!nr_devices) {
1956                 smp_mb();
1957                 nr_devices = fs_info->fs_devices->open_devices;
1958                 ASSERT(nr_devices);
1959                 if (!nr_devices) {
1960                         *free_bytes = 0;
1961                         return 0;
1962                 }
1963         }
1964
1965         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1966                                GFP_KERNEL);
1967         if (!devices_info)
1968                 return -ENOMEM;
1969
1970         /* calc min stripe number for data space allocation */
1971         type = btrfs_data_alloc_profile(fs_info);
1972         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1973                 min_stripes = 2;
1974                 num_stripes = nr_devices;
1975         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1976                 min_stripes = 2;
1977                 num_stripes = 2;
1978         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1979                 min_stripes = 4;
1980                 num_stripes = 4;
1981         }
1982
1983         if (type & BTRFS_BLOCK_GROUP_DUP)
1984                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1985         else
1986                 min_stripe_size = BTRFS_STRIPE_LEN;
1987
1988         rcu_read_lock();
1989         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1990                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1991                                                 &device->dev_state) ||
1992                     !device->bdev ||
1993                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1994                         continue;
1995
1996                 if (i >= nr_devices)
1997                         break;
1998
1999                 avail_space = device->total_bytes - device->bytes_used;
2000
2001                 /* align with stripe_len */
2002                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
2003                 avail_space *= BTRFS_STRIPE_LEN;
2004
2005                 /*
2006                  * In order to avoid overwriting the superblock on the drive,
2007                  * btrfs starts at an offset of at least 1MB when doing chunk
2008                  * allocation.
2009                  */
2010                 skip_space = SZ_1M;
2011
2012                 /*
2013                  * we can use the free space in [0, skip_space - 1], subtract
2014                  * it from the total.
2015                  */
2016                 if (avail_space && avail_space >= skip_space)
2017                         avail_space -= skip_space;
2018                 else
2019                         avail_space = 0;
2020
2021                 if (avail_space < min_stripe_size)
2022                         continue;
2023
2024                 devices_info[i].dev = device;
2025                 devices_info[i].max_avail = avail_space;
2026
2027                 i++;
2028         }
2029         rcu_read_unlock();
2030
2031         nr_devices = i;
2032
2033         btrfs_descending_sort_devices(devices_info, nr_devices);
2034
2035         i = nr_devices - 1;
2036         avail_space = 0;
2037         while (nr_devices >= min_stripes) {
2038                 if (num_stripes > nr_devices)
2039                         num_stripes = nr_devices;
2040
2041                 if (devices_info[i].max_avail >= min_stripe_size) {
2042                         int j;
2043                         u64 alloc_size;
2044
2045                         avail_space += devices_info[i].max_avail * num_stripes;
2046                         alloc_size = devices_info[i].max_avail;
2047                         for (j = i + 1 - num_stripes; j <= i; j++)
2048                                 devices_info[j].max_avail -= alloc_size;
2049                 }
2050                 i--;
2051                 nr_devices--;
2052         }
2053
2054         kfree(devices_info);
2055         *free_bytes = avail_space;
2056         return 0;
2057 }
2058
2059 /*
2060  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2061  *
2062  * If there's a redundant raid level at DATA block groups, use the respective
2063  * multiplier to scale the sizes.
2064  *
2065  * Unused device space usage is based on simulating the chunk allocator
2066  * algorithm that respects the device sizes and order of allocations.  This is
2067  * a close approximation of the actual use but there are other factors that may
2068  * change the result (like a new metadata chunk).
2069  *
2070  * If metadata is exhausted, f_bavail will be 0.
2071  */
2072 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2073 {
2074         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2075         struct btrfs_super_block *disk_super = fs_info->super_copy;
2076         struct list_head *head = &fs_info->space_info;
2077         struct btrfs_space_info *found;
2078         u64 total_used = 0;
2079         u64 total_free_data = 0;
2080         u64 total_free_meta = 0;
2081         int bits = dentry->d_sb->s_blocksize_bits;
2082         __be32 *fsid = (__be32 *)fs_info->fsid;
2083         unsigned factor = 1;
2084         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2085         int ret;
2086         u64 thresh = 0;
2087         int mixed = 0;
2088
2089         rcu_read_lock();
2090         list_for_each_entry_rcu(found, head, list) {
2091                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2092                         int i;
2093
2094                         total_free_data += found->disk_total - found->disk_used;
2095                         total_free_data -=
2096                                 btrfs_account_ro_block_groups_free_space(found);
2097
2098                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2099                                 if (!list_empty(&found->block_groups[i])) {
2100                                         switch (i) {
2101                                         case BTRFS_RAID_DUP:
2102                                         case BTRFS_RAID_RAID1:
2103                                         case BTRFS_RAID_RAID10:
2104                                                 factor = 2;
2105                                         }
2106                                 }
2107                         }
2108                 }
2109
2110                 /*
2111                  * Metadata in mixed block goup profiles are accounted in data
2112                  */
2113                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2114                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2115                                 mixed = 1;
2116                         else
2117                                 total_free_meta += found->disk_total -
2118                                         found->disk_used;
2119                 }
2120
2121                 total_used += found->disk_used;
2122         }
2123
2124         rcu_read_unlock();
2125
2126         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2127         buf->f_blocks >>= bits;
2128         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2129
2130         /* Account global block reserve as used, it's in logical size already */
2131         spin_lock(&block_rsv->lock);
2132         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2133         if (buf->f_bfree >= block_rsv->size >> bits)
2134                 buf->f_bfree -= block_rsv->size >> bits;
2135         else
2136                 buf->f_bfree = 0;
2137         spin_unlock(&block_rsv->lock);
2138
2139         buf->f_bavail = div_u64(total_free_data, factor);
2140         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2141         if (ret)
2142                 return ret;
2143         buf->f_bavail += div_u64(total_free_data, factor);
2144         buf->f_bavail = buf->f_bavail >> bits;
2145
2146         /*
2147          * We calculate the remaining metadata space minus global reserve. If
2148          * this is (supposedly) smaller than zero, there's no space. But this
2149          * does not hold in practice, the exhausted state happens where's still
2150          * some positive delta. So we apply some guesswork and compare the
2151          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2152          *
2153          * We probably cannot calculate the exact threshold value because this
2154          * depends on the internal reservations requested by various
2155          * operations, so some operations that consume a few metadata will
2156          * succeed even if the Avail is zero. But this is better than the other
2157          * way around.
2158          */
2159         thresh = SZ_4M;
2160
2161         if (!mixed && total_free_meta - thresh < block_rsv->size)
2162                 buf->f_bavail = 0;
2163
2164         buf->f_type = BTRFS_SUPER_MAGIC;
2165         buf->f_bsize = dentry->d_sb->s_blocksize;
2166         buf->f_namelen = BTRFS_NAME_LEN;
2167
2168         /* We treat it as constant endianness (it doesn't matter _which_)
2169            because we want the fsid to come out the same whether mounted
2170            on a big-endian or little-endian host */
2171         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2172         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2173         /* Mask in the root object ID too, to disambiguate subvols */
2174         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2175         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2176
2177         return 0;
2178 }
2179
2180 static void btrfs_kill_super(struct super_block *sb)
2181 {
2182         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2183         kill_anon_super(sb);
2184         free_fs_info(fs_info);
2185 }
2186
2187 static struct file_system_type btrfs_fs_type = {
2188         .owner          = THIS_MODULE,
2189         .name           = "btrfs",
2190         .mount          = btrfs_mount,
2191         .kill_sb        = btrfs_kill_super,
2192         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2193 };
2194
2195 static struct file_system_type btrfs_root_fs_type = {
2196         .owner          = THIS_MODULE,
2197         .name           = "btrfs",
2198         .mount          = btrfs_mount_root,
2199         .kill_sb        = btrfs_kill_super,
2200         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2201 };
2202
2203 MODULE_ALIAS_FS("btrfs");
2204
2205 static int btrfs_control_open(struct inode *inode, struct file *file)
2206 {
2207         /*
2208          * The control file's private_data is used to hold the
2209          * transaction when it is started and is used to keep
2210          * track of whether a transaction is already in progress.
2211          */
2212         file->private_data = NULL;
2213         return 0;
2214 }
2215
2216 /*
2217  * used by btrfsctl to scan devices when no FS is mounted
2218  */
2219 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2220                                 unsigned long arg)
2221 {
2222         struct btrfs_ioctl_vol_args *vol;
2223         struct btrfs_fs_devices *fs_devices;
2224         int ret = -ENOTTY;
2225
2226         if (!capable(CAP_SYS_ADMIN))
2227                 return -EPERM;
2228
2229         vol = memdup_user((void __user *)arg, sizeof(*vol));
2230         if (IS_ERR(vol))
2231                 return PTR_ERR(vol);
2232
2233         switch (cmd) {
2234         case BTRFS_IOC_SCAN_DEV:
2235                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2236                                             &btrfs_root_fs_type, &fs_devices);
2237                 break;
2238         case BTRFS_IOC_DEVICES_READY:
2239                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2240                                             &btrfs_root_fs_type, &fs_devices);
2241                 if (ret)
2242                         break;
2243                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2244                 break;
2245         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2246                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2247                 break;
2248         }
2249
2250         kfree(vol);
2251         return ret;
2252 }
2253
2254 static int btrfs_freeze(struct super_block *sb)
2255 {
2256         struct btrfs_trans_handle *trans;
2257         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2258         struct btrfs_root *root = fs_info->tree_root;
2259
2260         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2261         /*
2262          * We don't need a barrier here, we'll wait for any transaction that
2263          * could be in progress on other threads (and do delayed iputs that
2264          * we want to avoid on a frozen filesystem), or do the commit
2265          * ourselves.
2266          */
2267         trans = btrfs_attach_transaction_barrier(root);
2268         if (IS_ERR(trans)) {
2269                 /* no transaction, don't bother */
2270                 if (PTR_ERR(trans) == -ENOENT)
2271                         return 0;
2272                 return PTR_ERR(trans);
2273         }
2274         return btrfs_commit_transaction(trans);
2275 }
2276
2277 static int btrfs_unfreeze(struct super_block *sb)
2278 {
2279         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2280
2281         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2282         return 0;
2283 }
2284
2285 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2286 {
2287         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2288         struct btrfs_fs_devices *cur_devices;
2289         struct btrfs_device *dev, *first_dev = NULL;
2290         struct list_head *head;
2291         struct rcu_string *name;
2292
2293         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2294         cur_devices = fs_info->fs_devices;
2295         while (cur_devices) {
2296                 head = &cur_devices->devices;
2297                 list_for_each_entry(dev, head, dev_list) {
2298                         if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
2299                                 continue;
2300                         if (!dev->name)
2301                                 continue;
2302                         if (!first_dev || dev->devid < first_dev->devid)
2303                                 first_dev = dev;
2304                 }
2305                 cur_devices = cur_devices->seed;
2306         }
2307
2308         if (first_dev) {
2309                 rcu_read_lock();
2310                 name = rcu_dereference(first_dev->name);
2311                 seq_escape(m, name->str, " \t\n\\");
2312                 rcu_read_unlock();
2313         } else {
2314                 WARN_ON(1);
2315         }
2316         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2317         return 0;
2318 }
2319
2320 static const struct super_operations btrfs_super_ops = {
2321         .drop_inode     = btrfs_drop_inode,
2322         .evict_inode    = btrfs_evict_inode,
2323         .put_super      = btrfs_put_super,
2324         .sync_fs        = btrfs_sync_fs,
2325         .show_options   = btrfs_show_options,
2326         .show_devname   = btrfs_show_devname,
2327         .write_inode    = btrfs_write_inode,
2328         .alloc_inode    = btrfs_alloc_inode,
2329         .destroy_inode  = btrfs_destroy_inode,
2330         .statfs         = btrfs_statfs,
2331         .remount_fs     = btrfs_remount,
2332         .freeze_fs      = btrfs_freeze,
2333         .unfreeze_fs    = btrfs_unfreeze,
2334 };
2335
2336 static const struct file_operations btrfs_ctl_fops = {
2337         .open = btrfs_control_open,
2338         .unlocked_ioctl  = btrfs_control_ioctl,
2339         .compat_ioctl = btrfs_control_ioctl,
2340         .owner   = THIS_MODULE,
2341         .llseek = noop_llseek,
2342 };
2343
2344 static struct miscdevice btrfs_misc = {
2345         .minor          = BTRFS_MINOR,
2346         .name           = "btrfs-control",
2347         .fops           = &btrfs_ctl_fops
2348 };
2349
2350 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2351 MODULE_ALIAS("devname:btrfs-control");
2352
2353 static int __init btrfs_interface_init(void)
2354 {
2355         return misc_register(&btrfs_misc);
2356 }
2357
2358 static void btrfs_interface_exit(void)
2359 {
2360         misc_deregister(&btrfs_misc);
2361 }
2362
2363 static void __init btrfs_print_mod_info(void)
2364 {
2365         pr_info("Btrfs loaded, crc32c=%s"
2366 #ifdef CONFIG_BTRFS_DEBUG
2367                         ", debug=on"
2368 #endif
2369 #ifdef CONFIG_BTRFS_ASSERT
2370                         ", assert=on"
2371 #endif
2372 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2373                         ", integrity-checker=on"
2374 #endif
2375 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2376                         ", ref-verify=on"
2377 #endif
2378                         "\n",
2379                         btrfs_crc32c_impl());
2380 }
2381
2382 static int __init init_btrfs_fs(void)
2383 {
2384         int err;
2385
2386         err = btrfs_hash_init();
2387         if (err)
2388                 return err;
2389
2390         btrfs_props_init();
2391
2392         err = btrfs_init_sysfs();
2393         if (err)
2394                 goto free_hash;
2395
2396         btrfs_init_compress();
2397
2398         err = btrfs_init_cachep();
2399         if (err)
2400                 goto free_compress;
2401
2402         err = extent_io_init();
2403         if (err)
2404                 goto free_cachep;
2405
2406         err = extent_map_init();
2407         if (err)
2408                 goto free_extent_io;
2409
2410         err = ordered_data_init();
2411         if (err)
2412                 goto free_extent_map;
2413
2414         err = btrfs_delayed_inode_init();
2415         if (err)
2416                 goto free_ordered_data;
2417
2418         err = btrfs_auto_defrag_init();
2419         if (err)
2420                 goto free_delayed_inode;
2421
2422         err = btrfs_delayed_ref_init();
2423         if (err)
2424                 goto free_auto_defrag;
2425
2426         err = btrfs_prelim_ref_init();
2427         if (err)
2428                 goto free_delayed_ref;
2429
2430         err = btrfs_end_io_wq_init();
2431         if (err)
2432                 goto free_prelim_ref;
2433
2434         err = btrfs_interface_init();
2435         if (err)
2436                 goto free_end_io_wq;
2437
2438         btrfs_init_lockdep();
2439
2440         btrfs_print_mod_info();
2441
2442         err = btrfs_run_sanity_tests();
2443         if (err)
2444                 goto unregister_ioctl;
2445
2446         err = register_filesystem(&btrfs_fs_type);
2447         if (err)
2448                 goto unregister_ioctl;
2449
2450         return 0;
2451
2452 unregister_ioctl:
2453         btrfs_interface_exit();
2454 free_end_io_wq:
2455         btrfs_end_io_wq_exit();
2456 free_prelim_ref:
2457         btrfs_prelim_ref_exit();
2458 free_delayed_ref:
2459         btrfs_delayed_ref_exit();
2460 free_auto_defrag:
2461         btrfs_auto_defrag_exit();
2462 free_delayed_inode:
2463         btrfs_delayed_inode_exit();
2464 free_ordered_data:
2465         ordered_data_exit();
2466 free_extent_map:
2467         extent_map_exit();
2468 free_extent_io:
2469         extent_io_exit();
2470 free_cachep:
2471         btrfs_destroy_cachep();
2472 free_compress:
2473         btrfs_exit_compress();
2474         btrfs_exit_sysfs();
2475 free_hash:
2476         btrfs_hash_exit();
2477         return err;
2478 }
2479
2480 static void __exit exit_btrfs_fs(void)
2481 {
2482         btrfs_destroy_cachep();
2483         btrfs_delayed_ref_exit();
2484         btrfs_auto_defrag_exit();
2485         btrfs_delayed_inode_exit();
2486         btrfs_prelim_ref_exit();
2487         ordered_data_exit();
2488         extent_map_exit();
2489         extent_io_exit();
2490         btrfs_interface_exit();
2491         btrfs_end_io_wq_exit();
2492         unregister_filesystem(&btrfs_fs_type);
2493         btrfs_exit_sysfs();
2494         btrfs_cleanup_fs_uuids();
2495         btrfs_exit_compress();
2496         btrfs_hash_exit();
2497 }
2498
2499 late_initcall(init_btrfs_fs);
2500 module_exit(exit_btrfs_fs)
2501
2502 MODULE_LICENSE("GPL");