fs/btrfs/super.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/blkdev.h>
   7 #include <linux/module.h>
   8 #include <linux/fs.h>
   9 #include <linux/pagemap.h>
  10 #include <linux/highmem.h>
  11 #include <linux/time.h>
  12 #include <linux/init.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/string.h>
  15 #include <linux/backing-dev.h>
  16 #include <linux/mount.h>
  17 #include <linux/writeback.h>
  18 #include <linux/statfs.h>
  19 #include <linux/compat.h>
  20 #include <linux/parser.h>
  21 #include <linux/ctype.h>
  22 #include <linux/namei.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/magic.h>
  25 #include <linux/slab.h>
  26 #include <linux/cleancache.h>
  27 #include <linux/ratelimit.h>
  28 #include <linux/crc32c.h>
  29 #include <linux/btrfs.h>
  30 #include "delayed-inode.h"
  31 #include "ctree.h"
  32 #include "disk-io.h"
  33 #include "transaction.h"
  34 #include "btrfs_inode.h"
  35 #include "print-tree.h"
  36 #include "props.h"
  37 #include "xattr.h"
  38 #include "volumes.h"
  39 #include "export.h"
  40 #include "compression.h"
  41 #include "rcu-string.h"
  42 #include "dev-replace.h"
  43 #include "free-space-cache.h"
  44 #include "backref.h"
  45 #include "space-info.h"
  46 #include "sysfs.h"
  47 #include "tests/btrfs-tests.h"
  48 #include "block-group.h"
  49 #include "discard.h"
  50
  51 #include "qgroup.h"
  52 #define CREATE_TRACE_POINTS
  53 #include <trace/events/btrfs.h>
  54
  55 static const struct super_operations btrfs_super_ops;
  56
  57 /*
  58  * Types for mounting the default subvolume and a subvolume explicitly
  59  * requested by subvol=/path. That way the callchain is straightforward and we
  60  * don't have to play tricks with the mount options and recursive calls to
  61  * btrfs_mount.
  62  *
  63  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
  64  */
  65 static struct file_system_type btrfs_fs_type;
  66 static struct file_system_type btrfs_root_fs_type;
  67
  68 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  69
  70 const char * __attribute_const__ btrfs_decode_error(int errno)
  71 {
  72         char *errstr = "unknown";
  73
  74         switch (errno) {
  75         case -EIO:
  76                 errstr = "IO failure";
  77                 break;
  78         case -ENOMEM:
  79                 errstr = "Out of memory";
  80                 break;
  81         case -EROFS:
  82                 errstr = "Readonly filesystem";
  83                 break;
  84         case -EEXIST:
  85                 errstr = "Object already exists";
  86                 break;
  87         case -ENOSPC:
  88                 errstr = "No space left";
  89                 break;
  90         case -ENOENT:
  91                 errstr = "No such entry";
  92                 break;
  93         }
  94
  95         return errstr;
  96 }
  97
  98 /*
  99  * __btrfs_handle_fs_error decodes expected errors from the caller and
 100  * invokes the appropriate error response.
 101  */
 102 __cold
 103 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 104                        unsigned int line, int errno, const char *fmt, ...)
 105 {
 106         struct super_block *sb = fs_info->sb;
 107 #ifdef CONFIG_PRINTK
 108         const char *errstr;
 109 #endif
 110
 111         /*
 112          * Special case: if the error is EROFS, and we're already
 113          * under SB_RDONLY, then it is safe here.
 114          */
 115         if (errno == -EROFS && sb_rdonly(sb))
 116                 return;
 117
 118 #ifdef CONFIG_PRINTK
 119         errstr = btrfs_decode_error(errno);
 120         if (fmt) {
 121                 struct va_format vaf;
 122                 va_list args;
 123
 124                 va_start(args, fmt);
 125                 vaf.fmt = fmt;
 126                 vaf.va = &args;
 127
 128                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 129                         sb->s_id, function, line, errno, errstr, &vaf);
 130                 va_end(args);
 131         } else {
 132                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 133                         sb->s_id, function, line, errno, errstr);
 134         }
 135 #endif
 136
 137         /*
 138          * Today we only save the error info to memory.  Long term we'll
 139          * also send it down to the disk
 140          */
 141         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 142
 143         /* Don't go through full error handling during mount */
 144         if (!(sb->s_flags & SB_BORN))
 145                 return;
 146
 147         if (sb_rdonly(sb))
 148                 return;
 149
 150         btrfs_discard_stop(fs_info);
 151
 152         /* btrfs handle error by forcing the filesystem readonly */
 153         sb->s_flags |= SB_RDONLY;
 154         btrfs_info(fs_info, "forced readonly");
 155         /*
 156          * Note that a running device replace operation is not canceled here
 157          * although there is no way to update the progress. It would add the
 158          * risk of a deadlock, therefore the canceling is omitted. The only
 159          * penalty is that some I/O remains active until the procedure
 160          * completes. The next time when the filesystem is mounted writable
 161          * again, the device replace operation continues.
 162          */
 163 }
 164
 165 #ifdef CONFIG_PRINTK
 166 static const char * const logtypes[] = {
 167         "emergency",
 168         "alert",
 169         "critical",
 170         "error",
 171         "warning",
 172         "notice",
 173         "info",
 174         "debug",
 175 };
 176
 177
 178 /*
 179  * Use one ratelimit state per log level so that a flood of less important
 180  * messages doesn't cause more important ones to be dropped.
 181  */
 182 static struct ratelimit_state printk_limits[] = {
 183         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 184         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 185         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 186         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 187         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 188         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 189         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 190         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 191 };
 192
 193 void __cold btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 194 {
 195         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
 196         struct va_format vaf;
 197         va_list args;
 198         int kern_level;
 199         const char *type = logtypes[4];
 200         struct ratelimit_state *ratelimit = &printk_limits[4];
 201
 202         va_start(args, fmt);
 203
 204         while ((kern_level = printk_get_level(fmt)) != 0) {
 205                 size_t size = printk_skip_level(fmt) - fmt;
 206
 207                 if (kern_level >= '0' && kern_level <= '7') {
 208                         memcpy(lvl, fmt,  size);
 209                         lvl[size] = '\0';
 210                         type = logtypes[kern_level - '0'];
 211                         ratelimit = &printk_limits[kern_level - '0'];
 212                 }
 213                 fmt += size;
 214         }
 215
 216         vaf.fmt = fmt;
 217         vaf.va = &args;
 218
 219         if (__ratelimit(ratelimit))
 220                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type,
 221                         fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);
 222
 223         va_end(args);
 224 }
 225 #endif
 226
 227 /*
 228  * We only mark the transaction aborted and then set the file system read-only.
 229  * This will prevent new transactions from starting or trying to join this
 230  * one.
 231  *
 232  * This means that error recovery at the call site is limited to freeing
 233  * any local memory allocations and passing the error code up without
 234  * further cleanup. The transaction should complete as it normally would
 235  * in the call path but will return -EIO.
 236  *
 237  * We'll complete the cleanup in btrfs_end_transaction and
 238  * btrfs_commit_transaction.
 239  */
 240 __cold
 241 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 242                                const char *function,
 243                                unsigned int line, int errno)
 244 {
 245         struct btrfs_fs_info *fs_info = trans->fs_info;
 246
 247         trans->aborted = errno;
 248         /* Nothing used. The other threads that have joined this
 249          * transaction may be able to continue. */
 250         if (!trans->dirty && list_empty(&trans->new_bgs)) {
 251                 const char *errstr;
 252
 253                 errstr = btrfs_decode_error(errno);
 254                 btrfs_warn(fs_info,
 255                            "%s:%d: Aborting unused transaction(%s).",
 256                            function, line, errstr);
 257                 return;
 258         }
 259         WRITE_ONCE(trans->transaction->aborted, errno);
 260         /* Wake up anybody who may be waiting on this transaction */
 261         wake_up(&fs_info->transaction_wait);
 262         wake_up(&fs_info->transaction_blocked_wait);
 263         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 264 }
 265 /*
 266  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 267  * issues an alert, and either panics or BUGs, depending on mount options.
 268  */
 269 __cold
 270 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 271                    unsigned int line, int errno, const char *fmt, ...)
 272 {
 273         char *s_id = "<unknown>";
 274         const char *errstr;
 275         struct va_format vaf = { .fmt = fmt };
 276         va_list args;
 277
 278         if (fs_info)
 279                 s_id = fs_info->sb->s_id;
 280
 281         va_start(args, fmt);
 282         vaf.va = &args;
 283
 284         errstr = btrfs_decode_error(errno);
 285         if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
 286                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 287                         s_id, function, line, &vaf, errno, errstr);
 288
 289         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 290                    function, line, &vaf, errno, errstr);
 291         va_end(args);
 292         /* Caller calls BUG() */
 293 }
 294
 295 static void btrfs_put_super(struct super_block *sb)
 296 {
 297         close_ctree(btrfs_sb(sb));
 298 }
 299
 300 enum {
 301         Opt_acl, Opt_noacl,
 302         Opt_clear_cache,
 303         Opt_commit_interval,
 304         Opt_compress,
 305         Opt_compress_force,
 306         Opt_compress_force_type,
 307         Opt_compress_type,
 308         Opt_degraded,
 309         Opt_device,
 310         Opt_fatal_errors,
 311         Opt_flushoncommit, Opt_noflushoncommit,
 312         Opt_inode_cache, Opt_noinode_cache,
 313         Opt_max_inline,
 314         Opt_barrier, Opt_nobarrier,
 315         Opt_datacow, Opt_nodatacow,
 316         Opt_datasum, Opt_nodatasum,
 317         Opt_defrag, Opt_nodefrag,
 318         Opt_discard, Opt_nodiscard,
 319         Opt_discard_mode,
 320         Opt_nologreplay,
 321         Opt_norecovery,
 322         Opt_ratio,
 323         Opt_rescan_uuid_tree,
 324         Opt_skip_balance,
 325         Opt_space_cache, Opt_no_space_cache,
 326         Opt_space_cache_version,
 327         Opt_ssd, Opt_nossd,
 328         Opt_ssd_spread, Opt_nossd_spread,
 329         Opt_subvol,
 330         Opt_subvol_empty,
 331         Opt_subvolid,
 332         Opt_thread_pool,
 333         Opt_treelog, Opt_notreelog,
 334         Opt_usebackuproot,
 335         Opt_user_subvol_rm_allowed,
 336
 337         /* Deprecated options */
 338         Opt_alloc_start,
 339         Opt_recovery,
 340         Opt_subvolrootid,
 341
 342         /* Debugging options */
 343         Opt_check_integrity,
 344         Opt_check_integrity_including_extent_data,
 345         Opt_check_integrity_print_mask,
 346         Opt_enospc_debug, Opt_noenospc_debug,
 347 #ifdef CONFIG_BTRFS_DEBUG
 348         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 349 #endif
 350 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 351         Opt_ref_verify,
 352 #endif
 353         Opt_err,
 354 };
 355
 356 static const match_table_t tokens = {
 357         {Opt_acl, "acl"},
 358         {Opt_noacl, "noacl"},
 359         {Opt_clear_cache, "clear_cache"},
 360         {Opt_commit_interval, "commit=%u"},
 361         {Opt_compress, "compress"},
 362         {Opt_compress_type, "compress=%s"},
 363         {Opt_compress_force, "compress-force"},
 364         {Opt_compress_force_type, "compress-force=%s"},
 365         {Opt_degraded, "degraded"},
 366         {Opt_device, "device=%s"},
 367         {Opt_fatal_errors, "fatal_errors=%s"},
 368         {Opt_flushoncommit, "flushoncommit"},
 369         {Opt_noflushoncommit, "noflushoncommit"},
 370         {Opt_inode_cache, "inode_cache"},
 371         {Opt_noinode_cache, "noinode_cache"},
 372         {Opt_max_inline, "max_inline=%s"},
 373         {Opt_barrier, "barrier"},
 374         {Opt_nobarrier, "nobarrier"},
 375         {Opt_datacow, "datacow"},
 376         {Opt_nodatacow, "nodatacow"},
 377         {Opt_datasum, "datasum"},
 378         {Opt_nodatasum, "nodatasum"},
 379         {Opt_defrag, "autodefrag"},
 380         {Opt_nodefrag, "noautodefrag"},
 381         {Opt_discard, "discard"},
 382         {Opt_discard_mode, "discard=%s"},
 383         {Opt_nodiscard, "nodiscard"},
 384         {Opt_nologreplay, "nologreplay"},
 385         {Opt_norecovery, "norecovery"},
 386         {Opt_ratio, "metadata_ratio=%u"},
 387         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 388         {Opt_skip_balance, "skip_balance"},
 389         {Opt_space_cache, "space_cache"},
 390         {Opt_no_space_cache, "nospace_cache"},
 391         {Opt_space_cache_version, "space_cache=%s"},
 392         {Opt_ssd, "ssd"},
 393         {Opt_nossd, "nossd"},
 394         {Opt_ssd_spread, "ssd_spread"},
 395         {Opt_nossd_spread, "nossd_spread"},
 396         {Opt_subvol, "subvol=%s"},
 397         {Opt_subvol_empty, "subvol="},
 398         {Opt_subvolid, "subvolid=%s"},
 399         {Opt_thread_pool, "thread_pool=%u"},
 400         {Opt_treelog, "treelog"},
 401         {Opt_notreelog, "notreelog"},
 402         {Opt_usebackuproot, "usebackuproot"},
 403         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 404
 405         /* Deprecated options */
 406         {Opt_alloc_start, "alloc_start=%s"},
 407         {Opt_recovery, "recovery"},
 408         {Opt_subvolrootid, "subvolrootid=%d"},
 409
 410         /* Debugging options */
 411         {Opt_check_integrity, "check_int"},
 412         {Opt_check_integrity_including_extent_data, "check_int_data"},
 413         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
 414         {Opt_enospc_debug, "enospc_debug"},
 415         {Opt_noenospc_debug, "noenospc_debug"},
 416 #ifdef CONFIG_BTRFS_DEBUG
 417         {Opt_fragment_data, "fragment=data"},
 418         {Opt_fragment_metadata, "fragment=metadata"},
 419         {Opt_fragment_all, "fragment=all"},
 420 #endif
 421 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 422         {Opt_ref_verify, "ref_verify"},
 423 #endif
 424         {Opt_err, NULL},
 425 };
 426
 427 /*
 428  * Regular mount options parser.  Everything that is needed only when
 429  * reading in a new superblock is parsed here.
 430  * XXX JDM: This needs to be cleaned up for remount.
 431  */
 432 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 433                         unsigned long new_flags)
 434 {
 435         substring_t args[MAX_OPT_ARGS];
 436         char *p, *num;
 437         u64 cache_gen;
 438         int intarg;
 439         int ret = 0;
 440         char *compress_type;
 441         bool compress_force = false;
 442         enum btrfs_compression_type saved_compress_type;
 443         bool saved_compress_force;
 444         int no_compress = 0;
 445
 446         cache_gen = btrfs_super_cache_generation(info->super_copy);
 447         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 448                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 449         else if (cache_gen)
 450                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 451
 452         /*
 453          * Even the options are empty, we still need to do extra check
 454          * against new flags
 455          */
 456         if (!options)
 457                 goto check;
 458
 459         while ((p = strsep(&options, ",")) != NULL) {
 460                 int token;
 461                 if (!*p)
 462                         continue;
 463
 464                 token = match_token(p, tokens, args);
 465                 switch (token) {
 466                 case Opt_degraded:
 467                         btrfs_info(info, "allowing degraded mounts");
 468                         btrfs_set_opt(info->mount_opt, DEGRADED);
 469                         break;
 470                 case Opt_subvol:
 471                 case Opt_subvol_empty:
 472                 case Opt_subvolid:
 473                 case Opt_subvolrootid:
 474                 case Opt_device:
 475                         /*
 476                          * These are parsed by btrfs_parse_subvol_options or
 477                          * btrfs_parse_device_options and can be ignored here.
 478                          */
 479                         break;
 480                 case Opt_nodatasum:
 481                         btrfs_set_and_info(info, NODATASUM,
 482                                            "setting nodatasum");
 483                         break;
 484                 case Opt_datasum:
 485                         if (btrfs_test_opt(info, NODATASUM)) {
 486                                 if (btrfs_test_opt(info, NODATACOW))
 487                                         btrfs_info(info,
 488                                                    "setting datasum, datacow enabled");
 489                                 else
 490                                         btrfs_info(info, "setting datasum");
 491                         }
 492                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 493                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 494                         break;
 495                 case Opt_nodatacow:
 496                         if (!btrfs_test_opt(info, NODATACOW)) {
 497                                 if (!btrfs_test_opt(info, COMPRESS) ||
 498                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 499                                         btrfs_info(info,
 500                                                    "setting nodatacow, compression disabled");
 501                                 } else {
 502                                         btrfs_info(info, "setting nodatacow");
 503                                 }
 504                         }
 505                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 506                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 507                         btrfs_set_opt(info->mount_opt, NODATACOW);
 508                         btrfs_set_opt(info->mount_opt, NODATASUM);
 509                         break;
 510                 case Opt_datacow:
 511                         btrfs_clear_and_info(info, NODATACOW,
 512                                              "setting datacow");
 513                         break;
 514                 case Opt_compress_force:
 515                 case Opt_compress_force_type:
 516                         compress_force = true;
 517                         /* Fallthrough */
 518                 case Opt_compress:
 519                 case Opt_compress_type:
 520                         saved_compress_type = btrfs_test_opt(info,
 521                                                              COMPRESS) ?
 522                                 info->compress_type : BTRFS_COMPRESS_NONE;
 523                         saved_compress_force =
 524                                 btrfs_test_opt(info, FORCE_COMPRESS);
 525                         if (token == Opt_compress ||
 526                             token == Opt_compress_force ||
 527                             strncmp(args[0].from, "zlib", 4) == 0) {
 528                                 compress_type = "zlib";
 529
 530                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 531                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 532                                 /*
 533                                  * args[0] contains uninitialized data since
 534                                  * for these tokens we don't expect any
 535                                  * parameter.
 536                                  */
 537                                 if (token != Opt_compress &&
 538                                     token != Opt_compress_force)
 539                                         info->compress_level =
 540                                           btrfs_compress_str2level(
 541                                                         BTRFS_COMPRESS_ZLIB,
 542                                                         args[0].from + 4);
 543                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 544                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 545                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 546                                 no_compress = 0;
 547                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 548                                 compress_type = "lzo";
 549                                 info->compress_type = BTRFS_COMPRESS_LZO;
 550                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 551                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 552                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 553                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 554                                 no_compress = 0;
 555                         } else if (strncmp(args[0].from, "zstd", 4) == 0) {
 556                                 compress_type = "zstd";
 557                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 558                                 info->compress_level =
 559                                         btrfs_compress_str2level(
 560                                                          BTRFS_COMPRESS_ZSTD,
 561                                                          args[0].from + 4);
 562                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 563                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 564                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 565                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 566                                 no_compress = 0;
 567                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 568                                 compress_type = "no";
 569                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 570                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 571                                 compress_force = false;
 572                                 no_compress++;
 573                         } else {
 574                                 ret = -EINVAL;
 575                                 goto out;
 576                         }
 577
 578                         if (compress_force) {
 579                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 580                         } else {
 581                                 /*
 582                                  * If we remount from compress-force=xxx to
 583                                  * compress=xxx, we need clear FORCE_COMPRESS
 584                                  * flag, otherwise, there is no way for users
 585                                  * to disable forcible compression separately.
 586                                  */
 587                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 588                         }
 589                         if ((btrfs_test_opt(info, COMPRESS) &&
 590                              (info->compress_type != saved_compress_type ||
 591                               compress_force != saved_compress_force)) ||
 592                             (!btrfs_test_opt(info, COMPRESS) &&
 593                              no_compress == 1)) {
 594                                 btrfs_info(info, "%s %s compression, level %d",
 595                                            (compress_force) ? "force" : "use",
 596                                            compress_type, info->compress_level);
 597                         }
 598                         compress_force = false;
 599                         break;
 600                 case Opt_ssd:
 601                         btrfs_set_and_info(info, SSD,
 602                                            "enabling ssd optimizations");
 603                         btrfs_clear_opt(info->mount_opt, NOSSD);
 604                         break;
 605                 case Opt_ssd_spread:
 606                         btrfs_set_and_info(info, SSD,
 607                                            "enabling ssd optimizations");
 608                         btrfs_set_and_info(info, SSD_SPREAD,
 609                                            "using spread ssd allocation scheme");
 610                         btrfs_clear_opt(info->mount_opt, NOSSD);
 611                         break;
 612                 case Opt_nossd:
 613                         btrfs_set_opt(info->mount_opt, NOSSD);
 614                         btrfs_clear_and_info(info, SSD,
 615                                              "not using ssd optimizations");
 616                         /* Fallthrough */
 617                 case Opt_nossd_spread:
 618                         btrfs_clear_and_info(info, SSD_SPREAD,
 619                                              "not using spread ssd allocation scheme");
 620                         break;
 621                 case Opt_barrier:
 622                         btrfs_clear_and_info(info, NOBARRIER,
 623                                              "turning on barriers");
 624                         break;
 625                 case Opt_nobarrier:
 626                         btrfs_set_and_info(info, NOBARRIER,
 627                                            "turning off barriers");
 628                         break;
 629                 case Opt_thread_pool:
 630                         ret = match_int(&args[0], &intarg);
 631                         if (ret) {
 632                                 goto out;
 633                         } else if (intarg == 0) {
 634                                 ret = -EINVAL;
 635                                 goto out;
 636                         }
 637                         info->thread_pool_size = intarg;
 638                         break;
 639                 case Opt_max_inline:
 640                         num = match_strdup(&args[0]);
 641                         if (num) {
 642                                 info->max_inline = memparse(num, NULL);
 643                                 kfree(num);
 644
 645                                 if (info->max_inline) {
 646                                         info->max_inline = min_t(u64,
 647                                                 info->max_inline,
 648                                                 info->sectorsize);
 649                                 }
 650                                 btrfs_info(info, "max_inline at %llu",
 651                                            info->max_inline);
 652                         } else {
 653                                 ret = -ENOMEM;
 654                                 goto out;
 655                         }
 656                         break;
 657                 case Opt_alloc_start:
 658                         btrfs_info(info,
 659                                 "option alloc_start is obsolete, ignored");
 660                         break;
 661                 case Opt_acl:
 662 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 663                         info->sb->s_flags |= SB_POSIXACL;
 664                         break;
 665 #else
 666                         btrfs_err(info, "support for ACL not compiled in!");
 667                         ret = -EINVAL;
 668                         goto out;
 669 #endif
 670                 case Opt_noacl:
 671                         info->sb->s_flags &= ~SB_POSIXACL;
 672                         break;
 673                 case Opt_notreelog:
 674                         btrfs_set_and_info(info, NOTREELOG,
 675                                            "disabling tree log");
 676                         break;
 677                 case Opt_treelog:
 678                         btrfs_clear_and_info(info, NOTREELOG,
 679                                              "enabling tree log");
 680                         break;
 681                 case Opt_norecovery:
 682                 case Opt_nologreplay:
 683                         btrfs_set_and_info(info, NOLOGREPLAY,
 684                                            "disabling log replay at mount time");
 685                         break;
 686                 case Opt_flushoncommit:
 687                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 688                                            "turning on flush-on-commit");
 689                         break;
 690                 case Opt_noflushoncommit:
 691                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 692                                              "turning off flush-on-commit");
 693                         break;
 694                 case Opt_ratio:
 695                         ret = match_int(&args[0], &intarg);
 696                         if (ret)
 697                                 goto out;
 698                         info->metadata_ratio = intarg;
 699                         btrfs_info(info, "metadata ratio %u",
 700                                    info->metadata_ratio);
 701                         break;
 702                 case Opt_discard:
 703                 case Opt_discard_mode:
 704                         if (token == Opt_discard ||
 705                             strcmp(args[0].from, "sync") == 0) {
 706                                 btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
 707                                 btrfs_set_and_info(info, DISCARD_SYNC,
 708                                                    "turning on sync discard");
 709                         } else if (strcmp(args[0].from, "async") == 0) {
 710                                 btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
 711                                 btrfs_set_and_info(info, DISCARD_ASYNC,
 712                                                    "turning on async discard");
 713                         } else {
 714                                 ret = -EINVAL;
 715                                 goto out;
 716                         }
 717                         break;
 718                 case Opt_nodiscard:
 719                         btrfs_clear_and_info(info, DISCARD_SYNC,
 720                                              "turning off discard");
 721                         btrfs_clear_and_info(info, DISCARD_ASYNC,
 722                                              "turning off async discard");
 723                         break;
 724                 case Opt_space_cache:
 725                 case Opt_space_cache_version:
 726                         if (token == Opt_space_cache ||
 727                             strcmp(args[0].from, "v1") == 0) {
 728                                 btrfs_clear_opt(info->mount_opt,
 729                                                 FREE_SPACE_TREE);
 730                                 btrfs_set_and_info(info, SPACE_CACHE,
 731                                            "enabling disk space caching");
 732                         } else if (strcmp(args[0].from, "v2") == 0) {
 733                                 btrfs_clear_opt(info->mount_opt,
 734                                                 SPACE_CACHE);
 735                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 736                                                    "enabling free space tree");
 737                         } else {
 738                                 ret = -EINVAL;
 739                                 goto out;
 740                         }
 741                         break;
 742                 case Opt_rescan_uuid_tree:
 743                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 744                         break;
 745                 case Opt_no_space_cache:
 746                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 747                                 btrfs_clear_and_info(info, SPACE_CACHE,
 748                                              "disabling disk space caching");
 749                         }
 750                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 751                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 752                                              "disabling free space tree");
 753                         }
 754                         break;
 755                 case Opt_inode_cache:
 756                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 757                                            "enabling inode map caching");
 758                         break;
 759                 case Opt_noinode_cache:
 760                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 761                                              "disabling inode map caching");
 762                         break;
 763                 case Opt_clear_cache:
 764                         btrfs_set_and_info(info, CLEAR_CACHE,
 765                                            "force clearing of disk cache");
 766                         break;
 767                 case Opt_user_subvol_rm_allowed:
 768                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 769                         break;
 770                 case Opt_enospc_debug:
 771                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 772                         break;
 773                 case Opt_noenospc_debug:
 774                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 775                         break;
 776                 case Opt_defrag:
 777                         btrfs_set_and_info(info, AUTO_DEFRAG,
 778                                            "enabling auto defrag");
 779                         break;
 780                 case Opt_nodefrag:
 781                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 782                                              "disabling auto defrag");
 783                         break;
 784                 case Opt_recovery:
 785                         btrfs_warn(info,
 786                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 787                         /* fall through */
 788                 case Opt_usebackuproot:
 789                         btrfs_info(info,
 790                                    "trying to use backup root at mount time");
 791                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 792                         break;
 793                 case Opt_skip_balance:
 794                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 795                         break;
 796 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 797                 case Opt_check_integrity_including_extent_data:
 798                         btrfs_info(info,
 799                                    "enabling check integrity including extent data");
 800                         btrfs_set_opt(info->mount_opt,
 801                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 802                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 803                         break;
 804                 case Opt_check_integrity:
 805                         btrfs_info(info, "enabling check integrity");
 806                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 807                         break;
 808                 case Opt_check_integrity_print_mask:
 809                         ret = match_int(&args[0], &intarg);
 810                         if (ret)
 811                                 goto out;
 812                         info->check_integrity_print_mask = intarg;
 813                         btrfs_info(info, "check_integrity_print_mask 0x%x",
 814                                    info->check_integrity_print_mask);
 815                         break;
 816 #else
 817                 case Opt_check_integrity_including_extent_data:
 818                 case Opt_check_integrity:
 819                 case Opt_check_integrity_print_mask:
 820                         btrfs_err(info,
 821                                   "support for check_integrity* not compiled in!");
 822                         ret = -EINVAL;
 823                         goto out;
 824 #endif
 825                 case Opt_fatal_errors:
 826                         if (strcmp(args[0].from, "panic") == 0)
 827                                 btrfs_set_opt(info->mount_opt,
 828                                               PANIC_ON_FATAL_ERROR);
 829                         else if (strcmp(args[0].from, "bug") == 0)
 830                                 btrfs_clear_opt(info->mount_opt,
 831                                               PANIC_ON_FATAL_ERROR);
 832                         else {
 833                                 ret = -EINVAL;
 834                                 goto out;
 835                         }
 836                         break;
 837                 case Opt_commit_interval:
 838                         intarg = 0;
 839                         ret = match_int(&args[0], &intarg);
 840                         if (ret)
 841                                 goto out;
 842                         if (intarg == 0) {
 843                                 btrfs_info(info,
 844                                            "using default commit interval %us",
 845                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 846                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
 847                         } else if (intarg > 300) {
 848                                 btrfs_warn(info, "excessive commit interval %d",
 849                                            intarg);
 850                         }
 851                         info->commit_interval = intarg;
 852                         break;
 853 #ifdef CONFIG_BTRFS_DEBUG
 854                 case Opt_fragment_all:
 855                         btrfs_info(info, "fragmenting all space");
 856                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 857                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 858                         break;
 859                 case Opt_fragment_metadata:
 860                         btrfs_info(info, "fragmenting metadata");
 861                         btrfs_set_opt(info->mount_opt,
 862                                       FRAGMENT_METADATA);
 863                         break;
 864                 case Opt_fragment_data:
 865                         btrfs_info(info, "fragmenting data");
 866                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 867                         break;
 868 #endif
 869 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 870                 case Opt_ref_verify:
 871                         btrfs_info(info, "doing ref verification");
 872                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 873                         break;
 874 #endif
 875                 case Opt_err:
 876                         btrfs_info(info, "unrecognized mount option '%s'", p);
 877                         ret = -EINVAL;
 878                         goto out;
 879                 default:
 880                         break;
 881                 }
 882         }
 883 check:
 884         /*
 885          * Extra check for current option against current flag
 886          */
 887         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & SB_RDONLY)) {
 888                 btrfs_err(info,
 889                           "nologreplay must be used with ro mount option");
 890                 ret = -EINVAL;
 891         }
 892 out:
 893         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 894             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 895             !btrfs_test_opt(info, CLEAR_CACHE)) {
 896                 btrfs_err(info, "cannot disable free space tree");
 897                 ret = -EINVAL;
 898
 899         }
 900         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 901                 btrfs_info(info, "disk space caching is enabled");
 902         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 903                 btrfs_info(info, "using free space tree");
 904         return ret;
 905 }
 906
 907 /*
 908  * Parse mount options that are required early in the mount process.
 909  *
 910  * All other options will be parsed on much later in the mount process and
 911  * only when we need to allocate a new super block.
 912  */
 913 static int btrfs_parse_device_options(const char *options, fmode_t flags,
 914                                       void *holder)
 915 {
 916         substring_t args[MAX_OPT_ARGS];
 917         char *device_name, *opts, *orig, *p;
 918         struct btrfs_device *device = NULL;
 919         int error = 0;
 920
 921         lockdep_assert_held(&uuid_mutex);
 922
 923         if (!options)
 924                 return 0;
 925
 926         /*
 927          * strsep changes the string, duplicate it because btrfs_parse_options
 928          * gets called later
 929          */
 930         opts = kstrdup(options, GFP_KERNEL);
 931         if (!opts)
 932                 return -ENOMEM;
 933         orig = opts;
 934
 935         while ((p = strsep(&opts, ",")) != NULL) {
 936                 int token;
 937
 938                 if (!*p)
 939                         continue;
 940
 941                 token = match_token(p, tokens, args);
 942                 if (token == Opt_device) {
 943                         device_name = match_strdup(&args[0]);
 944                         if (!device_name) {
 945                                 error = -ENOMEM;
 946                                 goto out;
 947                         }
 948                         device = btrfs_scan_one_device(device_name, flags,
 949                                         holder);
 950                         kfree(device_name);
 951                         if (IS_ERR(device)) {
 952                                 error = PTR_ERR(device);
 953                                 goto out;
 954                         }
 955                 }
 956         }
 957
 958 out:
 959         kfree(orig);
 960         return error;
 961 }
 962
 963 /*
 964  * Parse mount options that are related to subvolume id
 965  *
 966  * The value is later passed to mount_subvol()
 967  */
 968 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
 969                 u64 *subvol_objectid)
 970 {
 971         substring_t args[MAX_OPT_ARGS];
 972         char *opts, *orig, *p;
 973         int error = 0;
 974         u64 subvolid;
 975
 976         if (!options)
 977                 return 0;
 978
 979         /*
 980          * strsep changes the string, duplicate it because
 981          * btrfs_parse_device_options gets called later
 982          */
 983         opts = kstrdup(options, GFP_KERNEL);
 984         if (!opts)
 985                 return -ENOMEM;
 986         orig = opts;
 987
 988         while ((p = strsep(&opts, ",")) != NULL) {
 989                 int token;
 990                 if (!*p)
 991                         continue;
 992
 993                 token = match_token(p, tokens, args);
 994                 switch (token) {
 995                 case Opt_subvol:
 996                         kfree(*subvol_name);
 997                         *subvol_name = match_strdup(&args[0]);
 998                         if (!*subvol_name) {
 999                                 error = -ENOMEM;
1000                                 goto out;
1001                         }
1002                         break;
1003                 case Opt_subvolid:
1004                         error = match_u64(&args[0], &subvolid);
1005                         if (error)
1006                                 goto out;
1007
1008                         /* we want the original fs_tree */
1009                         if (subvolid == 0)
1010                                 subvolid = BTRFS_FS_TREE_OBJECTID;
1011
1012                         *subvol_objectid = subvolid;
1013                         break;
1014                 case Opt_subvolrootid:
1015                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
1016                         break;
1017                 default:
1018                         break;
1019                 }
1020         }
1021
1022 out:
1023         kfree(orig);
1024         return error;
1025 }
1026
1027 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
1028                                            u64 subvol_objectid)
1029 {
1030         struct btrfs_root *root = fs_info->tree_root;
1031         struct btrfs_root *fs_root;
1032         struct btrfs_root_ref *root_ref;
1033         struct btrfs_inode_ref *inode_ref;
1034         struct btrfs_key key;
1035         struct btrfs_path *path = NULL;
1036         char *name = NULL, *ptr;
1037         u64 dirid;
1038         int len;
1039         int ret;
1040
1041         path = btrfs_alloc_path();
1042         if (!path) {
1043                 ret = -ENOMEM;
1044                 goto err;
1045         }
1046         path->leave_spinning = 1;
1047
1048         name = kmalloc(PATH_MAX, GFP_KERNEL);
1049         if (!name) {
1050                 ret = -ENOMEM;
1051                 goto err;
1052         }
1053         ptr = name + PATH_MAX - 1;
1054         ptr[0] = '\0';
1055
1056         /*
1057          * Walk up the subvolume trees in the tree of tree roots by root
1058          * backrefs until we hit the top-level subvolume.
1059          */
1060         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1061                 key.objectid = subvol_objectid;
1062                 key.type = BTRFS_ROOT_BACKREF_KEY;
1063                 key.offset = (u64)-1;
1064
1065                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1066                 if (ret < 0) {
1067                         goto err;
1068                 } else if (ret > 0) {
1069                         ret = btrfs_previous_item(root, path, subvol_objectid,
1070                                                   BTRFS_ROOT_BACKREF_KEY);
1071                         if (ret < 0) {
1072                                 goto err;
1073                         } else if (ret > 0) {
1074                                 ret = -ENOENT;
1075                                 goto err;
1076                         }
1077                 }
1078
1079                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1080                 subvol_objectid = key.offset;
1081
1082                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1083                                           struct btrfs_root_ref);
1084                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1085                 ptr -= len + 1;
1086                 if (ptr < name) {
1087                         ret = -ENAMETOOLONG;
1088                         goto err;
1089                 }
1090                 read_extent_buffer(path->nodes[0], ptr + 1,
1091                                    (unsigned long)(root_ref + 1), len);
1092                 ptr[0] = '/';
1093                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1094                 btrfs_release_path(path);
1095
1096                 key.objectid = subvol_objectid;
1097                 key.type = BTRFS_ROOT_ITEM_KEY;
1098                 key.offset = (u64)-1;
1099                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1100                 if (IS_ERR(fs_root)) {
1101                         ret = PTR_ERR(fs_root);
1102                         goto err;
1103                 }
1104
1105                 /*
1106                  * Walk up the filesystem tree by inode refs until we hit the
1107                  * root directory.
1108                  */
1109                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1110                         key.objectid = dirid;
1111                         key.type = BTRFS_INODE_REF_KEY;
1112                         key.offset = (u64)-1;
1113
1114                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1115                         if (ret < 0) {
1116                                 goto err;
1117                         } else if (ret > 0) {
1118                                 ret = btrfs_previous_item(fs_root, path, dirid,
1119                                                           BTRFS_INODE_REF_KEY);
1120                                 if (ret < 0) {
1121                                         goto err;
1122                                 } else if (ret > 0) {
1123                                         ret = -ENOENT;
1124                                         goto err;
1125                                 }
1126                         }
1127
1128                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1129                         dirid = key.offset;
1130
1131                         inode_ref = btrfs_item_ptr(path->nodes[0],
1132                                                    path->slots[0],
1133                                                    struct btrfs_inode_ref);
1134                         len = btrfs_inode_ref_name_len(path->nodes[0],
1135                                                        inode_ref);
1136                         ptr -= len + 1;
1137                         if (ptr < name) {
1138                                 ret = -ENAMETOOLONG;
1139                                 goto err;
1140                         }
1141                         read_extent_buffer(path->nodes[0], ptr + 1,
1142                                            (unsigned long)(inode_ref + 1), len);
1143                         ptr[0] = '/';
1144                         btrfs_release_path(path);
1145                 }
1146         }
1147
1148         btrfs_free_path(path);
1149         if (ptr == name + PATH_MAX - 1) {
1150                 name[0] = '/';
1151                 name[1] = '\0';
1152         } else {
1153                 memmove(name, ptr, name + PATH_MAX - ptr);
1154         }
1155         return name;
1156
1157 err:
1158         btrfs_free_path(path);
1159         kfree(name);
1160         return ERR_PTR(ret);
1161 }
1162
1163 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1164 {
1165         struct btrfs_root *root = fs_info->tree_root;
1166         struct btrfs_dir_item *di;
1167         struct btrfs_path *path;
1168         struct btrfs_key location;
1169         u64 dir_id;
1170
1171         path = btrfs_alloc_path();
1172         if (!path)
1173                 return -ENOMEM;
1174         path->leave_spinning = 1;
1175
1176         /*
1177          * Find the "default" dir item which points to the root item that we
1178          * will mount by default if we haven't been given a specific subvolume
1179          * to mount.
1180          */
1181         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1182         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1183         if (IS_ERR(di)) {
1184                 btrfs_free_path(path);
1185                 return PTR_ERR(di);
1186         }
1187         if (!di) {
1188                 /*
1189                  * Ok the default dir item isn't there.  This is weird since
1190                  * it's always been there, but don't freak out, just try and
1191                  * mount the top-level subvolume.
1192                  */
1193                 btrfs_free_path(path);
1194                 *objectid = BTRFS_FS_TREE_OBJECTID;
1195                 return 0;
1196         }
1197
1198         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1199         btrfs_free_path(path);
1200         *objectid = location.objectid;
1201         return 0;
1202 }
1203
1204 static int btrfs_fill_super(struct super_block *sb,
1205                             struct btrfs_fs_devices *fs_devices,
1206                             void *data)
1207 {
1208         struct inode *inode;
1209         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1210         struct btrfs_key key;
1211         int err;
1212
1213         sb->s_maxbytes = MAX_LFS_FILESIZE;
1214         sb->s_magic = BTRFS_SUPER_MAGIC;
1215         sb->s_op = &btrfs_super_ops;
1216         sb->s_d_op = &btrfs_dentry_operations;
1217         sb->s_export_op = &btrfs_export_ops;
1218         sb->s_xattr = btrfs_xattr_handlers;
1219         sb->s_time_gran = 1;
1220 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1221         sb->s_flags |= SB_POSIXACL;
1222 #endif
1223         sb->s_flags |= SB_I_VERSION;
1224         sb->s_iflags |= SB_I_CGROUPWB;
1225
1226         err = super_setup_bdi(sb);
1227         if (err) {
1228                 btrfs_err(fs_info, "super_setup_bdi failed");
1229                 return err;
1230         }
1231
1232         err = open_ctree(sb, fs_devices, (char *)data);
1233         if (err) {
1234                 btrfs_err(fs_info, "open_ctree failed");
1235                 return err;
1236         }
1237
1238         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1239         key.type = BTRFS_INODE_ITEM_KEY;
1240         key.offset = 0;
1241         inode = btrfs_iget(sb, &key, fs_info->fs_root);
1242         if (IS_ERR(inode)) {
1243                 err = PTR_ERR(inode);
1244                 goto fail_close;
1245         }
1246
1247         sb->s_root = d_make_root(inode);
1248         if (!sb->s_root) {
1249                 err = -ENOMEM;
1250                 goto fail_close;
1251         }
1252
1253         cleancache_init_fs(sb);
1254         sb->s_flags |= SB_ACTIVE;
1255         return 0;
1256
1257 fail_close:
1258         close_ctree(fs_info);
1259         return err;
1260 }
1261
1262 int btrfs_sync_fs(struct super_block *sb, int wait)
1263 {
1264         struct btrfs_trans_handle *trans;
1265         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1266         struct btrfs_root *root = fs_info->tree_root;
1267
1268         trace_btrfs_sync_fs(fs_info, wait);
1269
1270         if (!wait) {
1271                 filemap_flush(fs_info->btree_inode->i_mapping);
1272                 return 0;
1273         }
1274
1275         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1276
1277         trans = btrfs_attach_transaction_barrier(root);
1278         if (IS_ERR(trans)) {
1279                 /* no transaction, don't bother */
1280                 if (PTR_ERR(trans) == -ENOENT) {
1281                         /*
1282                          * Exit unless we have some pending changes
1283                          * that need to go through commit
1284                          */
1285                         if (fs_info->pending_changes == 0)
1286                                 return 0;
1287                         /*
1288                          * A non-blocking test if the fs is frozen. We must not
1289                          * start a new transaction here otherwise a deadlock
1290                          * happens. The pending operations are delayed to the
1291                          * next commit after thawing.
1292                          */
1293                         if (sb_start_write_trylock(sb))
1294                                 sb_end_write(sb);
1295                         else
1296                                 return 0;
1297                         trans = btrfs_start_transaction(root, 0);
1298                 }
1299                 if (IS_ERR(trans))
1300                         return PTR_ERR(trans);
1301         }
1302         return btrfs_commit_transaction(trans);
1303 }
1304
1305 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1306 {
1307         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1308         const char *compress_type;
1309
1310         if (btrfs_test_opt(info, DEGRADED))
1311                 seq_puts(seq, ",degraded");
1312         if (btrfs_test_opt(info, NODATASUM))
1313                 seq_puts(seq, ",nodatasum");
1314         if (btrfs_test_opt(info, NODATACOW))
1315                 seq_puts(seq, ",nodatacow");
1316         if (btrfs_test_opt(info, NOBARRIER))
1317                 seq_puts(seq, ",nobarrier");
1318         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1319                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1320         if (info->thread_pool_size !=  min_t(unsigned long,
1321                                              num_online_cpus() + 2, 8))
1322                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1323         if (btrfs_test_opt(info, COMPRESS)) {
1324                 compress_type = btrfs_compress_type2str(info->compress_type);
1325                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1326                         seq_printf(seq, ",compress-force=%s", compress_type);
1327                 else
1328                         seq_printf(seq, ",compress=%s", compress_type);
1329                 if (info->compress_level)
1330                         seq_printf(seq, ":%d", info->compress_level);
1331         }
1332         if (btrfs_test_opt(info, NOSSD))
1333                 seq_puts(seq, ",nossd");
1334         if (btrfs_test_opt(info, SSD_SPREAD))
1335                 seq_puts(seq, ",ssd_spread");
1336         else if (btrfs_test_opt(info, SSD))
1337                 seq_puts(seq, ",ssd");
1338         if (btrfs_test_opt(info, NOTREELOG))
1339                 seq_puts(seq, ",notreelog");
1340         if (btrfs_test_opt(info, NOLOGREPLAY))
1341                 seq_puts(seq, ",nologreplay");
1342         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1343                 seq_puts(seq, ",flushoncommit");
1344         if (btrfs_test_opt(info, DISCARD_SYNC))
1345                 seq_puts(seq, ",discard");
1346         if (btrfs_test_opt(info, DISCARD_ASYNC))
1347                 seq_puts(seq, ",discard=async");
1348         if (!(info->sb->s_flags & SB_POSIXACL))
1349                 seq_puts(seq, ",noacl");
1350         if (btrfs_test_opt(info, SPACE_CACHE))
1351                 seq_puts(seq, ",space_cache");
1352         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1353                 seq_puts(seq, ",space_cache=v2");
1354         else
1355                 seq_puts(seq, ",nospace_cache");
1356         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1357                 seq_puts(seq, ",rescan_uuid_tree");
1358         if (btrfs_test_opt(info, CLEAR_CACHE))
1359                 seq_puts(seq, ",clear_cache");
1360         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1361                 seq_puts(seq, ",user_subvol_rm_allowed");
1362         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1363                 seq_puts(seq, ",enospc_debug");
1364         if (btrfs_test_opt(info, AUTO_DEFRAG))
1365                 seq_puts(seq, ",autodefrag");
1366         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1367                 seq_puts(seq, ",inode_cache");
1368         if (btrfs_test_opt(info, SKIP_BALANCE))
1369                 seq_puts(seq, ",skip_balance");
1370 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1371         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1372                 seq_puts(seq, ",check_int_data");
1373         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1374                 seq_puts(seq, ",check_int");
1375         if (info->check_integrity_print_mask)
1376                 seq_printf(seq, ",check_int_print_mask=%d",
1377                                 info->check_integrity_print_mask);
1378 #endif
1379         if (info->metadata_ratio)
1380                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1381         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1382                 seq_puts(seq, ",fatal_errors=panic");
1383         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1384                 seq_printf(seq, ",commit=%u", info->commit_interval);
1385 #ifdef CONFIG_BTRFS_DEBUG
1386         if (btrfs_test_opt(info, FRAGMENT_DATA))
1387                 seq_puts(seq, ",fragment=data");
1388         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1389                 seq_puts(seq, ",fragment=metadata");
1390 #endif
1391         if (btrfs_test_opt(info, REF_VERIFY))
1392                 seq_puts(seq, ",ref_verify");
1393         seq_printf(seq, ",subvolid=%llu",
1394                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1395         seq_puts(seq, ",subvol=");
1396         seq_dentry(seq, dentry, " \t\n\\");
1397         return 0;
1398 }
1399
1400 static int btrfs_test_super(struct super_block *s, void *data)
1401 {
1402         struct btrfs_fs_info *p = data;
1403         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1404
1405         return fs_info->fs_devices == p->fs_devices;
1406 }
1407
1408 static int btrfs_set_super(struct super_block *s, void *data)
1409 {
1410         int err = set_anon_super(s, data);
1411         if (!err)
1412                 s->s_fs_info = data;
1413         return err;
1414 }
1415
1416 /*
1417  * subvolumes are identified by ino 256
1418  */
1419 static inline int is_subvolume_inode(struct inode *inode)
1420 {
1421         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1422                 return 1;
1423         return 0;
1424 }
1425
1426 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1427                                    struct vfsmount *mnt)
1428 {
1429         struct dentry *root;
1430         int ret;
1431
1432         if (!subvol_name) {
1433                 if (!subvol_objectid) {
1434                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1435                                                           &subvol_objectid);
1436                         if (ret) {
1437                                 root = ERR_PTR(ret);
1438                                 goto out;
1439                         }
1440                 }
1441                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1442                                                             subvol_objectid);
1443                 if (IS_ERR(subvol_name)) {
1444                         root = ERR_CAST(subvol_name);
1445                         subvol_name = NULL;
1446                         goto out;
1447                 }
1448
1449         }
1450
1451         root = mount_subtree(mnt, subvol_name);
1452         /* mount_subtree() drops our reference on the vfsmount. */
1453         mnt = NULL;
1454
1455         if (!IS_ERR(root)) {
1456                 struct super_block *s = root->d_sb;
1457                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1458                 struct inode *root_inode = d_inode(root);
1459                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1460
1461                 ret = 0;
1462                 if (!is_subvolume_inode(root_inode)) {
1463                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1464                                subvol_name);
1465                         ret = -EINVAL;
1466                 }
1467                 if (subvol_objectid && root_objectid != subvol_objectid) {
1468                         /*
1469                          * This will also catch a race condition where a
1470                          * subvolume which was passed by ID is renamed and
1471                          * another subvolume is renamed over the old location.
1472                          */
1473                         btrfs_err(fs_info,
1474                                   "subvol '%s' does not match subvolid %llu",
1475                                   subvol_name, subvol_objectid);
1476                         ret = -EINVAL;
1477                 }
1478                 if (ret) {
1479                         dput(root);
1480                         root = ERR_PTR(ret);
1481                         deactivate_locked_super(s);
1482                 }
1483         }
1484
1485 out:
1486         mntput(mnt);
1487         kfree(subvol_name);
1488         return root;
1489 }
1490
1491 /*
1492  * Find a superblock for the given device / mount point.
1493  *
1494  * Note: This is based on mount_bdev from fs/super.c with a few additions
1495  *       for multiple device setup.  Make sure to keep it in sync.
1496  */
1497 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1498                 int flags, const char *device_name, void *data)
1499 {
1500         struct block_device *bdev = NULL;
1501         struct super_block *s;
1502         struct btrfs_device *device = NULL;
1503         struct btrfs_fs_devices *fs_devices = NULL;
1504         struct btrfs_fs_info *fs_info = NULL;
1505         void *new_sec_opts = NULL;
1506         fmode_t mode = FMODE_READ;
1507         int error = 0;
1508
1509         if (!(flags & SB_RDONLY))
1510                 mode |= FMODE_WRITE;
1511
1512         if (data) {
1513                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1514                 if (error)
1515                         return ERR_PTR(error);
1516         }
1517
1518         /*
1519          * Setup a dummy root and fs_info for test/set super.  This is because
1520          * we don't actually fill this stuff out until open_ctree, but we need
1521          * it for searching for existing supers, so this lets us do that and
1522          * then open_ctree will properly initialize everything later.
1523          */
1524         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1525         if (!fs_info) {
1526                 error = -ENOMEM;
1527                 goto error_sec_opts;
1528         }
1529
1530         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1531         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1532         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1533                 error = -ENOMEM;
1534                 goto error_fs_info;
1535         }
1536
1537         mutex_lock(&uuid_mutex);
1538         error = btrfs_parse_device_options(data, mode, fs_type);
1539         if (error) {
1540                 mutex_unlock(&uuid_mutex);
1541                 goto error_fs_info;
1542         }
1543
1544         device = btrfs_scan_one_device(device_name, mode, fs_type);
1545         if (IS_ERR(device)) {
1546                 mutex_unlock(&uuid_mutex);
1547                 error = PTR_ERR(device);
1548                 goto error_fs_info;
1549         }
1550
1551         fs_devices = device->fs_devices;
1552         fs_info->fs_devices = fs_devices;
1553
1554         error = btrfs_open_devices(fs_devices, mode, fs_type);
1555         mutex_unlock(&uuid_mutex);
1556         if (error)
1557                 goto error_fs_info;
1558
1559         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1560                 error = -EACCES;
1561                 goto error_close_devices;
1562         }
1563
1564         bdev = fs_devices->latest_bdev;
1565         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1566                  fs_info);
1567         if (IS_ERR(s)) {
1568                 error = PTR_ERR(s);
1569                 goto error_close_devices;
1570         }
1571
1572         if (s->s_root) {
1573                 btrfs_close_devices(fs_devices);
1574                 free_fs_info(fs_info);
1575                 if ((flags ^ s->s_flags) & SB_RDONLY)
1576                         error = -EBUSY;
1577         } else {
1578                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1579                 btrfs_sb(s)->bdev_holder = fs_type;
1580                 if (!strstr(crc32c_impl(), "generic"))
1581                         set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
1582                 error = btrfs_fill_super(s, fs_devices, data);
1583         }
1584         if (!error)
1585                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1586         security_free_mnt_opts(&new_sec_opts);
1587         if (error) {
1588                 deactivate_locked_super(s);
1589                 return ERR_PTR(error);
1590         }
1591
1592         return dget(s->s_root);
1593
1594 error_close_devices:
1595         btrfs_close_devices(fs_devices);
1596 error_fs_info:
1597         free_fs_info(fs_info);
1598 error_sec_opts:
1599         security_free_mnt_opts(&new_sec_opts);
1600         return ERR_PTR(error);
1601 }
1602
1603 /*
1604  * Mount function which is called by VFS layer.
1605  *
1606  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1607  * which needs vfsmount* of device's root (/).  This means device's root has to
1608  * be mounted internally in any case.
1609  *
1610  * Operation flow:
1611  *   1. Parse subvol id related options for later use in mount_subvol().
1612  *
1613  *   2. Mount device's root (/) by calling vfs_kern_mount().
1614  *
1615  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1616  *      first place. In order to avoid calling btrfs_mount() again, we use
1617  *      different file_system_type which is not registered to VFS by
1618  *      register_filesystem() (btrfs_root_fs_type). As a result,
1619  *      btrfs_mount_root() is called. The return value will be used by
1620  *      mount_subtree() in mount_subvol().
1621  *
1622  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1623  *      "btrfs subvolume set-default", mount_subvol() is called always.
1624  */
1625 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1626                 const char *device_name, void *data)
1627 {
1628         struct vfsmount *mnt_root;
1629         struct dentry *root;
1630         char *subvol_name = NULL;
1631         u64 subvol_objectid = 0;
1632         int error = 0;
1633
1634         error = btrfs_parse_subvol_options(data, &subvol_name,
1635                                         &subvol_objectid);
1636         if (error) {
1637                 kfree(subvol_name);
1638                 return ERR_PTR(error);
1639         }
1640
1641         /* mount device's root (/) */
1642         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1643         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1644                 if (flags & SB_RDONLY) {
1645                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1646                                 flags & ~SB_RDONLY, device_name, data);
1647                 } else {
1648                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1649                                 flags | SB_RDONLY, device_name, data);
1650                         if (IS_ERR(mnt_root)) {
1651                                 root = ERR_CAST(mnt_root);
1652                                 kfree(subvol_name);
1653                                 goto out;
1654                         }
1655
1656                         down_write(&mnt_root->mnt_sb->s_umount);
1657                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1658                         up_write(&mnt_root->mnt_sb->s_umount);
1659                         if (error < 0) {
1660                                 root = ERR_PTR(error);
1661                                 mntput(mnt_root);
1662                                 kfree(subvol_name);
1663                                 goto out;
1664                         }
1665                 }
1666         }
1667         if (IS_ERR(mnt_root)) {
1668                 root = ERR_CAST(mnt_root);
1669                 kfree(subvol_name);
1670                 goto out;
1671         }
1672
1673         /* mount_subvol() will free subvol_name and mnt_root */
1674         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1675
1676 out:
1677         return root;
1678 }
1679
1680 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1681                                      u32 new_pool_size, u32 old_pool_size)
1682 {
1683         if (new_pool_size == old_pool_size)
1684                 return;
1685
1686         fs_info->thread_pool_size = new_pool_size;
1687
1688         btrfs_info(fs_info, "resize thread pool %d -> %d",
1689                old_pool_size, new_pool_size);
1690
1691         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1692         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1693         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1694         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1695         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1696         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1697                                 new_pool_size);
1698         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1699         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1700         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1701         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1702         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1703                                 new_pool_size);
1704 }
1705
1706 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1707 {
1708         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1709 }
1710
1711 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1712                                        unsigned long old_opts, int flags)
1713 {
1714         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1715             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1716              (flags & SB_RDONLY))) {
1717                 /* wait for any defraggers to finish */
1718                 wait_event(fs_info->transaction_wait,
1719                            (atomic_read(&fs_info->defrag_running) == 0));
1720                 if (flags & SB_RDONLY)
1721                         sync_filesystem(fs_info->sb);
1722         }
1723 }
1724
1725 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1726                                          unsigned long old_opts)
1727 {
1728         /*
1729          * We need to cleanup all defragable inodes if the autodefragment is
1730          * close or the filesystem is read only.
1731          */
1732         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1733             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1734                 btrfs_cleanup_defrag_inodes(fs_info);
1735         }
1736
1737         /* If we toggled discard async */
1738         if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1739             btrfs_test_opt(fs_info, DISCARD_ASYNC))
1740                 btrfs_discard_resume(fs_info);
1741         else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1742                  !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1743                 btrfs_discard_cleanup(fs_info);
1744
1745         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1746 }
1747
1748 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1749 {
1750         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1751         struct btrfs_root *root = fs_info->tree_root;
1752         unsigned old_flags = sb->s_flags;
1753         unsigned long old_opts = fs_info->mount_opt;
1754         unsigned long old_compress_type = fs_info->compress_type;
1755         u64 old_max_inline = fs_info->max_inline;
1756         u32 old_thread_pool_size = fs_info->thread_pool_size;
1757         u32 old_metadata_ratio = fs_info->metadata_ratio;
1758         int ret;
1759
1760         sync_filesystem(sb);
1761         btrfs_remount_prepare(fs_info);
1762
1763         if (data) {
1764                 void *new_sec_opts = NULL;
1765
1766                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1767                 if (!ret)
1768                         ret = security_sb_remount(sb, new_sec_opts);
1769                 security_free_mnt_opts(&new_sec_opts);
1770                 if (ret)
1771                         goto restore;
1772         }
1773
1774         ret = btrfs_parse_options(fs_info, data, *flags);
1775         if (ret)
1776                 goto restore;
1777
1778         btrfs_remount_begin(fs_info, old_opts, *flags);
1779         btrfs_resize_thread_pool(fs_info,
1780                 fs_info->thread_pool_size, old_thread_pool_size);
1781
1782         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1783                 goto out;
1784
1785         if (*flags & SB_RDONLY) {
1786                 /*
1787                  * this also happens on 'umount -rf' or on shutdown, when
1788                  * the filesystem is busy.
1789                  */
1790                 cancel_work_sync(&fs_info->async_reclaim_work);
1791
1792                 btrfs_discard_cleanup(fs_info);
1793
1794                 /* wait for the uuid_scan task to finish */
1795                 down(&fs_info->uuid_tree_rescan_sem);
1796                 /* avoid complains from lockdep et al. */
1797                 up(&fs_info->uuid_tree_rescan_sem);
1798
1799                 sb->s_flags |= SB_RDONLY;
1800
1801                 /*
1802                  * Setting SB_RDONLY will put the cleaner thread to
1803                  * sleep at the next loop if it's already active.
1804                  * If it's already asleep, we'll leave unused block
1805                  * groups on disk until we're mounted read-write again
1806                  * unless we clean them up here.
1807                  */
1808                 btrfs_delete_unused_bgs(fs_info);
1809
1810                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1811                 btrfs_scrub_cancel(fs_info);
1812                 btrfs_pause_balance(fs_info);
1813
1814                 ret = btrfs_commit_super(fs_info);
1815                 if (ret)
1816                         goto restore;
1817         } else {
1818                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1819                         btrfs_err(fs_info,
1820                                 "Remounting read-write after error is not allowed");
1821                         ret = -EINVAL;
1822                         goto restore;
1823                 }
1824                 if (fs_info->fs_devices->rw_devices == 0) {
1825                         ret = -EACCES;
1826                         goto restore;
1827                 }
1828
1829                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1830                         btrfs_warn(fs_info,
1831                 "too many missing devices, writable remount is not allowed");
1832                         ret = -EACCES;
1833                         goto restore;
1834                 }
1835
1836                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1837                         btrfs_warn(fs_info,
1838                 "mount required to replay tree-log, cannot remount read-write");
1839                         ret = -EINVAL;
1840                         goto restore;
1841                 }
1842
1843                 ret = btrfs_cleanup_fs_roots(fs_info);
1844                 if (ret)
1845                         goto restore;
1846
1847                 /* recover relocation */
1848                 mutex_lock(&fs_info->cleaner_mutex);
1849                 ret = btrfs_recover_relocation(root);
1850                 mutex_unlock(&fs_info->cleaner_mutex);
1851                 if (ret)
1852                         goto restore;
1853
1854                 ret = btrfs_resume_balance_async(fs_info);
1855                 if (ret)
1856                         goto restore;
1857
1858                 ret = btrfs_resume_dev_replace_async(fs_info);
1859                 if (ret) {
1860                         btrfs_warn(fs_info, "failed to resume dev_replace");
1861                         goto restore;
1862                 }
1863
1864                 btrfs_qgroup_rescan_resume(fs_info);
1865
1866                 if (!fs_info->uuid_root) {
1867                         btrfs_info(fs_info, "creating UUID tree");
1868                         ret = btrfs_create_uuid_tree(fs_info);
1869                         if (ret) {
1870                                 btrfs_warn(fs_info,
1871                                            "failed to create the UUID tree %d",
1872                                            ret);
1873                                 goto restore;
1874                         }
1875                 }
1876                 sb->s_flags &= ~SB_RDONLY;
1877
1878                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1879         }
1880 out:
1881         wake_up_process(fs_info->transaction_kthread);
1882         btrfs_remount_cleanup(fs_info, old_opts);
1883         return 0;
1884
1885 restore:
1886         /* We've hit an error - don't reset SB_RDONLY */
1887         if (sb_rdonly(sb))
1888                 old_flags |= SB_RDONLY;
1889         sb->s_flags = old_flags;
1890         fs_info->mount_opt = old_opts;
1891         fs_info->compress_type = old_compress_type;
1892         fs_info->max_inline = old_max_inline;
1893         btrfs_resize_thread_pool(fs_info,
1894                 old_thread_pool_size, fs_info->thread_pool_size);
1895         fs_info->metadata_ratio = old_metadata_ratio;
1896         btrfs_remount_cleanup(fs_info, old_opts);
1897         return ret;
1898 }
1899
1900 /* Used to sort the devices by max_avail(descending sort) */
1901 static inline int btrfs_cmp_device_free_bytes(const void *dev_info1,
1902                                        const void *dev_info2)
1903 {
1904         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1905             ((struct btrfs_device_info *)dev_info2)->max_avail)
1906                 return -1;
1907         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1908                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1909                 return 1;
1910         else
1911         return 0;
1912 }
1913
1914 /*
1915  * sort the devices by max_avail, in which max free extent size of each device
1916  * is stored.(Descending Sort)
1917  */
1918 static inline void btrfs_descending_sort_devices(
1919                                         struct btrfs_device_info *devices,
1920                                         size_t nr_devices)
1921 {
1922         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1923              btrfs_cmp_device_free_bytes, NULL);
1924 }
1925
1926 /*
1927  * The helper to calc the free space on the devices that can be used to store
1928  * file data.
1929  */
1930 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1931                                               u64 *free_bytes)
1932 {
1933         struct btrfs_device_info *devices_info;
1934         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1935         struct btrfs_device *device;
1936         u64 type;
1937         u64 avail_space;
1938         u64 min_stripe_size;
1939         int num_stripes = 1;
1940         int i = 0, nr_devices;
1941         const struct btrfs_raid_attr *rattr;
1942
1943         /*
1944          * We aren't under the device list lock, so this is racy-ish, but good
1945          * enough for our purposes.
1946          */
1947         nr_devices = fs_info->fs_devices->open_devices;
1948         if (!nr_devices) {
1949                 smp_mb();
1950                 nr_devices = fs_info->fs_devices->open_devices;
1951                 ASSERT(nr_devices);
1952                 if (!nr_devices) {
1953                         *free_bytes = 0;
1954                         return 0;
1955                 }
1956         }
1957
1958         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1959                                GFP_KERNEL);
1960         if (!devices_info)
1961                 return -ENOMEM;
1962
1963         /* calc min stripe number for data space allocation */
1964         type = btrfs_data_alloc_profile(fs_info);
1965         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1966
1967         if (type & BTRFS_BLOCK_GROUP_RAID0)
1968                 num_stripes = nr_devices;
1969         else if (type & BTRFS_BLOCK_GROUP_RAID1)
1970                 num_stripes = 2;
1971         else if (type & BTRFS_BLOCK_GROUP_RAID1C3)
1972                 num_stripes = 3;
1973         else if (type & BTRFS_BLOCK_GROUP_RAID1C4)
1974                 num_stripes = 4;
1975         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1976                 num_stripes = 4;
1977
1978         /* Adjust for more than 1 stripe per device */
1979         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1980
1981         rcu_read_lock();
1982         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1983                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1984                                                 &device->dev_state) ||
1985                     !device->bdev ||
1986                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1987                         continue;
1988
1989                 if (i >= nr_devices)
1990                         break;
1991
1992                 avail_space = device->total_bytes - device->bytes_used;
1993
1994                 /* align with stripe_len */
1995                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1996
1997                 /*
1998                  * In order to avoid overwriting the superblock on the drive,
1999                  * btrfs starts at an offset of at least 1MB when doing chunk
2000                  * allocation.
2001                  *
2002                  * This ensures we have at least min_stripe_size free space
2003                  * after excluding 1MB.
2004                  */
2005                 if (avail_space <= SZ_1M + min_stripe_size)
2006                         continue;
2007
2008                 avail_space -= SZ_1M;
2009
2010                 devices_info[i].dev = device;
2011                 devices_info[i].max_avail = avail_space;
2012
2013                 i++;
2014         }
2015         rcu_read_unlock();
2016
2017         nr_devices = i;
2018
2019         btrfs_descending_sort_devices(devices_info, nr_devices);
2020
2021         i = nr_devices - 1;
2022         avail_space = 0;
2023         while (nr_devices >= rattr->devs_min) {
2024                 num_stripes = min(num_stripes, nr_devices);
2025
2026                 if (devices_info[i].max_avail >= min_stripe_size) {
2027                         int j;
2028                         u64 alloc_size;
2029
2030                         avail_space += devices_info[i].max_avail * num_stripes;
2031                         alloc_size = devices_info[i].max_avail;
2032                         for (j = i + 1 - num_stripes; j <= i; j++)
2033                                 devices_info[j].max_avail -= alloc_size;
2034                 }
2035                 i--;
2036                 nr_devices--;
2037         }
2038
2039         kfree(devices_info);
2040         *free_bytes = avail_space;
2041         return 0;
2042 }
2043
2044 /*
2045  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2046  *
2047  * If there's a redundant raid level at DATA block groups, use the respective
2048  * multiplier to scale the sizes.
2049  *
2050  * Unused device space usage is based on simulating the chunk allocator
2051  * algorithm that respects the device sizes and order of allocations.  This is
2052  * a close approximation of the actual use but there are other factors that may
2053  * change the result (like a new metadata chunk).
2054  *
2055  * If metadata is exhausted, f_bavail will be 0.
2056  */
2057 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2058 {
2059         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2060         struct btrfs_super_block *disk_super = fs_info->super_copy;
2061         struct btrfs_space_info *found;
2062         u64 total_used = 0;
2063         u64 total_free_data = 0;
2064         u64 total_free_meta = 0;
2065         int bits = dentry->d_sb->s_blocksize_bits;
2066         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2067         unsigned factor = 1;
2068         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2069         int ret;
2070         u64 thresh = 0;
2071         int mixed = 0;
2072
2073         rcu_read_lock();
2074         list_for_each_entry_rcu(found, &fs_info->space_info, list) {
2075                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2076                         int i;
2077
2078                         total_free_data += found->disk_total - found->disk_used;
2079                         total_free_data -=
2080                                 btrfs_account_ro_block_groups_free_space(found);
2081
2082                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2083                                 if (!list_empty(&found->block_groups[i]))
2084                                         factor = btrfs_bg_type_to_factor(
2085                                                 btrfs_raid_array[i].bg_flag);
2086                         }
2087                 }
2088
2089                 /*
2090                  * Metadata in mixed block goup profiles are accounted in data
2091                  */
2092                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2093                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2094                                 mixed = 1;
2095                         else
2096                                 total_free_meta += found->disk_total -
2097                                         found->disk_used;
2098                 }
2099
2100                 total_used += found->disk_used;
2101         }
2102
2103         rcu_read_unlock();
2104
2105         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2106         buf->f_blocks >>= bits;
2107         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2108
2109         /* Account global block reserve as used, it's in logical size already */
2110         spin_lock(&block_rsv->lock);
2111         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2112         if (buf->f_bfree >= block_rsv->size >> bits)
2113                 buf->f_bfree -= block_rsv->size >> bits;
2114         else
2115                 buf->f_bfree = 0;
2116         spin_unlock(&block_rsv->lock);
2117
2118         buf->f_bavail = div_u64(total_free_data, factor);
2119         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2120         if (ret)
2121                 return ret;
2122         buf->f_bavail += div_u64(total_free_data, factor);
2123         buf->f_bavail = buf->f_bavail >> bits;
2124
2125         /*
2126          * We calculate the remaining metadata space minus global reserve. If
2127          * this is (supposedly) smaller than zero, there's no space. But this
2128          * does not hold in practice, the exhausted state happens where's still
2129          * some positive delta. So we apply some guesswork and compare the
2130          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2131          *
2132          * We probably cannot calculate the exact threshold value because this
2133          * depends on the internal reservations requested by various
2134          * operations, so some operations that consume a few metadata will
2135          * succeed even if the Avail is zero. But this is better than the other
2136          * way around.
2137          */
2138         thresh = SZ_4M;
2139
2140         /*
2141          * We only want to claim there's no available space if we can no longer
2142          * allocate chunks for our metadata profile and our global reserve will
2143          * not fit in the free metadata space.  If we aren't ->full then we
2144          * still can allocate chunks and thus are fine using the currently
2145          * calculated f_bavail.
2146          */
2147         if (!mixed && block_rsv->space_info->full &&
2148             total_free_meta - thresh < block_rsv->size)
2149                 buf->f_bavail = 0;
2150
2151         buf->f_type = BTRFS_SUPER_MAGIC;
2152         buf->f_bsize = dentry->d_sb->s_blocksize;
2153         buf->f_namelen = BTRFS_NAME_LEN;
2154
2155         /* We treat it as constant endianness (it doesn't matter _which_)
2156            because we want the fsid to come out the same whether mounted
2157            on a big-endian or little-endian host */
2158         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2159         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2160         /* Mask in the root object ID too, to disambiguate subvols */
2161         buf->f_fsid.val[0] ^=
2162                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2163         buf->f_fsid.val[1] ^=
2164                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2165
2166         return 0;
2167 }
2168
2169 static void btrfs_kill_super(struct super_block *sb)
2170 {
2171         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2172         kill_anon_super(sb);
2173         free_fs_info(fs_info);
2174 }
2175
2176 static struct file_system_type btrfs_fs_type = {
2177         .owner          = THIS_MODULE,
2178         .name           = "btrfs",
2179         .mount          = btrfs_mount,
2180         .kill_sb        = btrfs_kill_super,
2181         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2182 };
2183
2184 static struct file_system_type btrfs_root_fs_type = {
2185         .owner          = THIS_MODULE,
2186         .name           = "btrfs",
2187         .mount          = btrfs_mount_root,
2188         .kill_sb        = btrfs_kill_super,
2189         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2190 };
2191
2192 MODULE_ALIAS_FS("btrfs");
2193
2194 static int btrfs_control_open(struct inode *inode, struct file *file)
2195 {
2196         /*
2197          * The control file's private_data is used to hold the
2198          * transaction when it is started and is used to keep
2199          * track of whether a transaction is already in progress.
2200          */
2201         file->private_data = NULL;
2202         return 0;
2203 }
2204
2205 /*
2206  * used by btrfsctl to scan devices when no FS is mounted
2207  */
2208 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2209                                 unsigned long arg)
2210 {
2211         struct btrfs_ioctl_vol_args *vol;
2212         struct btrfs_device *device = NULL;
2213         int ret = -ENOTTY;
2214
2215         if (!capable(CAP_SYS_ADMIN))
2216                 return -EPERM;
2217
2218         vol = memdup_user((void __user *)arg, sizeof(*vol));
2219         if (IS_ERR(vol))
2220                 return PTR_ERR(vol);
2221         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2222
2223         switch (cmd) {
2224         case BTRFS_IOC_SCAN_DEV:
2225                 mutex_lock(&uuid_mutex);
2226                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2227                                                &btrfs_root_fs_type);
2228                 ret = PTR_ERR_OR_ZERO(device);
2229                 mutex_unlock(&uuid_mutex);
2230                 break;
2231         case BTRFS_IOC_FORGET_DEV:
2232                 ret = btrfs_forget_devices(vol->name);
2233                 break;
2234         case BTRFS_IOC_DEVICES_READY:
2235                 mutex_lock(&uuid_mutex);
2236                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2237                                                &btrfs_root_fs_type);
2238                 if (IS_ERR(device)) {
2239                         mutex_unlock(&uuid_mutex);
2240                         ret = PTR_ERR(device);
2241                         break;
2242                 }
2243                 ret = !(device->fs_devices->num_devices ==
2244                         device->fs_devices->total_devices);
2245                 mutex_unlock(&uuid_mutex);
2246                 break;
2247         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2248                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2249                 break;
2250         }
2251
2252         kfree(vol);
2253         return ret;
2254 }
2255
2256 static int btrfs_freeze(struct super_block *sb)
2257 {
2258         struct btrfs_trans_handle *trans;
2259         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2260         struct btrfs_root *root = fs_info->tree_root;
2261
2262         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2263         /*
2264          * We don't need a barrier here, we'll wait for any transaction that
2265          * could be in progress on other threads (and do delayed iputs that
2266          * we want to avoid on a frozen filesystem), or do the commit
2267          * ourselves.
2268          */
2269         trans = btrfs_attach_transaction_barrier(root);
2270         if (IS_ERR(trans)) {
2271                 /* no transaction, don't bother */
2272                 if (PTR_ERR(trans) == -ENOENT)
2273                         return 0;
2274                 return PTR_ERR(trans);
2275         }
2276         return btrfs_commit_transaction(trans);
2277 }
2278
2279 static int btrfs_unfreeze(struct super_block *sb)
2280 {
2281         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2282
2283         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2284         return 0;
2285 }
2286
2287 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2288 {
2289         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2290         struct btrfs_fs_devices *cur_devices;
2291         struct btrfs_device *dev, *first_dev = NULL;
2292         struct list_head *head;
2293
2294         /*
2295          * Lightweight locking of the devices. We should not need
2296          * device_list_mutex here as we only read the device data and the list
2297          * is protected by RCU.  Even if a device is deleted during the list
2298          * traversals, we'll get valid data, the freeing callback will wait at
2299          * least until the rcu_read_unlock.
2300          */
2301         rcu_read_lock();
2302         cur_devices = fs_info->fs_devices;
2303         while (cur_devices) {
2304                 head = &cur_devices->devices;
2305                 list_for_each_entry_rcu(dev, head, dev_list) {
2306                         if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
2307                                 continue;
2308                         if (!dev->name)
2309                                 continue;
2310                         if (!first_dev || dev->devid < first_dev->devid)
2311                                 first_dev = dev;
2312                 }
2313                 cur_devices = cur_devices->seed;
2314         }
2315
2316         if (first_dev)
2317                 seq_escape(m, rcu_str_deref(first_dev->name), " \t\n\\");
2318         else
2319                 WARN_ON(1);
2320         rcu_read_unlock();
2321         return 0;
2322 }
2323
2324 static const struct super_operations btrfs_super_ops = {
2325         .drop_inode     = btrfs_drop_inode,
2326         .evict_inode    = btrfs_evict_inode,
2327         .put_super      = btrfs_put_super,
2328         .sync_fs        = btrfs_sync_fs,
2329         .show_options   = btrfs_show_options,
2330         .show_devname   = btrfs_show_devname,
2331         .alloc_inode    = btrfs_alloc_inode,
2332         .destroy_inode  = btrfs_destroy_inode,
2333         .free_inode     = btrfs_free_inode,
2334         .statfs         = btrfs_statfs,
2335         .remount_fs     = btrfs_remount,
2336         .freeze_fs      = btrfs_freeze,
2337         .unfreeze_fs    = btrfs_unfreeze,
2338 };
2339
2340 static const struct file_operations btrfs_ctl_fops = {
2341         .open = btrfs_control_open,
2342         .unlocked_ioctl  = btrfs_control_ioctl,
2343         .compat_ioctl = compat_ptr_ioctl,
2344         .owner   = THIS_MODULE,
2345         .llseek = noop_llseek,
2346 };
2347
2348 static struct miscdevice btrfs_misc = {
2349         .minor          = BTRFS_MINOR,
2350         .name           = "btrfs-control",
2351         .fops           = &btrfs_ctl_fops
2352 };
2353
2354 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2355 MODULE_ALIAS("devname:btrfs-control");
2356
2357 static int __init btrfs_interface_init(void)
2358 {
2359         return misc_register(&btrfs_misc);
2360 }
2361
2362 static __cold void btrfs_interface_exit(void)
2363 {
2364         misc_deregister(&btrfs_misc);
2365 }
2366
2367 static void __init btrfs_print_mod_info(void)
2368 {
2369         static const char options[] = ""
2370 #ifdef CONFIG_BTRFS_DEBUG
2371                         ", debug=on"
2372 #endif
2373 #ifdef CONFIG_BTRFS_ASSERT
2374                         ", assert=on"
2375 #endif
2376 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2377                         ", integrity-checker=on"
2378 #endif
2379 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2380                         ", ref-verify=on"
2381 #endif
2382                         ;
2383         pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
2384 }
2385
2386 static int __init init_btrfs_fs(void)
2387 {
2388         int err;
2389
2390         btrfs_props_init();
2391
2392         err = btrfs_init_sysfs();
2393         if (err)
2394                 return err;
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_state_cache_init();
2407         if (err)
2408                 goto free_extent_io;
2409
2410         err = extent_map_init();
2411         if (err)
2412                 goto free_extent_state_cache;
2413
2414         err = ordered_data_init();
2415         if (err)
2416                 goto free_extent_map;
2417
2418         err = btrfs_delayed_inode_init();
2419         if (err)
2420                 goto free_ordered_data;
2421
2422         err = btrfs_auto_defrag_init();
2423         if (err)
2424                 goto free_delayed_inode;
2425
2426         err = btrfs_delayed_ref_init();
2427         if (err)
2428                 goto free_auto_defrag;
2429
2430         err = btrfs_prelim_ref_init();
2431         if (err)
2432                 goto free_delayed_ref;
2433
2434         err = btrfs_end_io_wq_init();
2435         if (err)
2436                 goto free_prelim_ref;
2437
2438         err = btrfs_interface_init();
2439         if (err)
2440                 goto free_end_io_wq;
2441
2442         btrfs_init_lockdep();
2443
2444         btrfs_print_mod_info();
2445
2446         err = btrfs_run_sanity_tests();
2447         if (err)
2448                 goto unregister_ioctl;
2449
2450         err = register_filesystem(&btrfs_fs_type);
2451         if (err)
2452                 goto unregister_ioctl;
2453
2454         return 0;
2455
2456 unregister_ioctl:
2457         btrfs_interface_exit();
2458 free_end_io_wq:
2459         btrfs_end_io_wq_exit();
2460 free_prelim_ref:
2461         btrfs_prelim_ref_exit();
2462 free_delayed_ref:
2463         btrfs_delayed_ref_exit();
2464 free_auto_defrag:
2465         btrfs_auto_defrag_exit();
2466 free_delayed_inode:
2467         btrfs_delayed_inode_exit();
2468 free_ordered_data:
2469         ordered_data_exit();
2470 free_extent_map:
2471         extent_map_exit();
2472 free_extent_state_cache:
2473         extent_state_cache_exit();
2474 free_extent_io:
2475         extent_io_exit();
2476 free_cachep:
2477         btrfs_destroy_cachep();
2478 free_compress:
2479         btrfs_exit_compress();
2480         btrfs_exit_sysfs();
2481
2482         return err;
2483 }
2484
2485 static void __exit exit_btrfs_fs(void)
2486 {
2487         btrfs_destroy_cachep();
2488         btrfs_delayed_ref_exit();
2489         btrfs_auto_defrag_exit();
2490         btrfs_delayed_inode_exit();
2491         btrfs_prelim_ref_exit();
2492         ordered_data_exit();
2493         extent_map_exit();
2494         extent_state_cache_exit();
2495         extent_io_exit();
2496         btrfs_interface_exit();
2497         btrfs_end_io_wq_exit();
2498         unregister_filesystem(&btrfs_fs_type);
2499         btrfs_exit_sysfs();
2500         btrfs_cleanup_fs_uuids();
2501         btrfs_exit_compress();
2502 }
2503
2504 late_initcall(init_btrfs_fs);
2505 module_exit(exit_btrfs_fs)
2506
2507 MODULE_LICENSE("GPL");
2508 MODULE_SOFTDEP("pre: crc32c");
2509 MODULE_SOFTDEP("pre: xxhash64");
2510 MODULE_SOFTDEP("pre: sha256");
2511 MODULE_SOFTDEP("pre: blake2b-256");