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         WRITE_ONCE(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_err(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 char *btrfs_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 = NULL;
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_get_fs_root(fs_info, &key, true);
1100                 if (IS_ERR(fs_root)) {
1101                         ret = PTR_ERR(fs_root);
1102                         fs_root = NULL;
1103                         goto err;
1104                 }
1105
1106                 /*
1107                  * Walk up the filesystem tree by inode refs until we hit the
1108                  * root directory.
1109                  */
1110                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1111                         key.objectid = dirid;
1112                         key.type = BTRFS_INODE_REF_KEY;
1113                         key.offset = (u64)-1;
1114
1115                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1116                         if (ret < 0) {
1117                                 goto err;
1118                         } else if (ret > 0) {
1119                                 ret = btrfs_previous_item(fs_root, path, dirid,
1120                                                           BTRFS_INODE_REF_KEY);
1121                                 if (ret < 0) {
1122                                         goto err;
1123                                 } else if (ret > 0) {
1124                                         ret = -ENOENT;
1125                                         goto err;
1126                                 }
1127                         }
1128
1129                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1130                         dirid = key.offset;
1131
1132                         inode_ref = btrfs_item_ptr(path->nodes[0],
1133                                                    path->slots[0],
1134                                                    struct btrfs_inode_ref);
1135                         len = btrfs_inode_ref_name_len(path->nodes[0],
1136                                                        inode_ref);
1137                         ptr -= len + 1;
1138                         if (ptr < name) {
1139                                 ret = -ENAMETOOLONG;
1140                                 goto err;
1141                         }
1142                         read_extent_buffer(path->nodes[0], ptr + 1,
1143                                            (unsigned long)(inode_ref + 1), len);
1144                         ptr[0] = '/';
1145                         btrfs_release_path(path);
1146                 }
1147                 btrfs_put_root(fs_root);
1148                 fs_root = NULL;
1149         }
1150
1151         btrfs_free_path(path);
1152         if (ptr == name + PATH_MAX - 1) {
1153                 name[0] = '/';
1154                 name[1] = '\0';
1155         } else {
1156                 memmove(name, ptr, name + PATH_MAX - ptr);
1157         }
1158         return name;
1159
1160 err:
1161         btrfs_put_root(fs_root);
1162         btrfs_free_path(path);
1163         kfree(name);
1164         return ERR_PTR(ret);
1165 }
1166
1167 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1168 {
1169         struct btrfs_root *root = fs_info->tree_root;
1170         struct btrfs_dir_item *di;
1171         struct btrfs_path *path;
1172         struct btrfs_key location;
1173         u64 dir_id;
1174
1175         path = btrfs_alloc_path();
1176         if (!path)
1177                 return -ENOMEM;
1178         path->leave_spinning = 1;
1179
1180         /*
1181          * Find the "default" dir item which points to the root item that we
1182          * will mount by default if we haven't been given a specific subvolume
1183          * to mount.
1184          */
1185         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1186         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1187         if (IS_ERR(di)) {
1188                 btrfs_free_path(path);
1189                 return PTR_ERR(di);
1190         }
1191         if (!di) {
1192                 /*
1193                  * Ok the default dir item isn't there.  This is weird since
1194                  * it's always been there, but don't freak out, just try and
1195                  * mount the top-level subvolume.
1196                  */
1197                 btrfs_free_path(path);
1198                 *objectid = BTRFS_FS_TREE_OBJECTID;
1199                 return 0;
1200         }
1201
1202         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1203         btrfs_free_path(path);
1204         *objectid = location.objectid;
1205         return 0;
1206 }
1207
1208 static int btrfs_fill_super(struct super_block *sb,
1209                             struct btrfs_fs_devices *fs_devices,
1210                             void *data)
1211 {
1212         struct inode *inode;
1213         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1214         struct btrfs_key key;
1215         int err;
1216
1217         sb->s_maxbytes = MAX_LFS_FILESIZE;
1218         sb->s_magic = BTRFS_SUPER_MAGIC;
1219         sb->s_op = &btrfs_super_ops;
1220         sb->s_d_op = &btrfs_dentry_operations;
1221         sb->s_export_op = &btrfs_export_ops;
1222         sb->s_xattr = btrfs_xattr_handlers;
1223         sb->s_time_gran = 1;
1224 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1225         sb->s_flags |= SB_POSIXACL;
1226 #endif
1227         sb->s_flags |= SB_I_VERSION;
1228         sb->s_iflags |= SB_I_CGROUPWB;
1229
1230         err = super_setup_bdi(sb);
1231         if (err) {
1232                 btrfs_err(fs_info, "super_setup_bdi failed");
1233                 return err;
1234         }
1235
1236         err = open_ctree(sb, fs_devices, (char *)data);
1237         if (err) {
1238                 btrfs_err(fs_info, "open_ctree failed");
1239                 return err;
1240         }
1241
1242         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1243         key.type = BTRFS_INODE_ITEM_KEY;
1244         key.offset = 0;
1245         inode = btrfs_iget(sb, &key, fs_info->fs_root);
1246         if (IS_ERR(inode)) {
1247                 err = PTR_ERR(inode);
1248                 goto fail_close;
1249         }
1250
1251         sb->s_root = d_make_root(inode);
1252         if (!sb->s_root) {
1253                 err = -ENOMEM;
1254                 goto fail_close;
1255         }
1256
1257         cleancache_init_fs(sb);
1258         sb->s_flags |= SB_ACTIVE;
1259         return 0;
1260
1261 fail_close:
1262         close_ctree(fs_info);
1263         return err;
1264 }
1265
1266 int btrfs_sync_fs(struct super_block *sb, int wait)
1267 {
1268         struct btrfs_trans_handle *trans;
1269         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1270         struct btrfs_root *root = fs_info->tree_root;
1271
1272         trace_btrfs_sync_fs(fs_info, wait);
1273
1274         if (!wait) {
1275                 filemap_flush(fs_info->btree_inode->i_mapping);
1276                 return 0;
1277         }
1278
1279         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1280
1281         trans = btrfs_attach_transaction_barrier(root);
1282         if (IS_ERR(trans)) {
1283                 /* no transaction, don't bother */
1284                 if (PTR_ERR(trans) == -ENOENT) {
1285                         /*
1286                          * Exit unless we have some pending changes
1287                          * that need to go through commit
1288                          */
1289                         if (fs_info->pending_changes == 0)
1290                                 return 0;
1291                         /*
1292                          * A non-blocking test if the fs is frozen. We must not
1293                          * start a new transaction here otherwise a deadlock
1294                          * happens. The pending operations are delayed to the
1295                          * next commit after thawing.
1296                          */
1297                         if (sb_start_write_trylock(sb))
1298                                 sb_end_write(sb);
1299                         else
1300                                 return 0;
1301                         trans = btrfs_start_transaction(root, 0);
1302                 }
1303                 if (IS_ERR(trans))
1304                         return PTR_ERR(trans);
1305         }
1306         return btrfs_commit_transaction(trans);
1307 }
1308
1309 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1310 {
1311         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1312         const char *compress_type;
1313
1314         if (btrfs_test_opt(info, DEGRADED))
1315                 seq_puts(seq, ",degraded");
1316         if (btrfs_test_opt(info, NODATASUM))
1317                 seq_puts(seq, ",nodatasum");
1318         if (btrfs_test_opt(info, NODATACOW))
1319                 seq_puts(seq, ",nodatacow");
1320         if (btrfs_test_opt(info, NOBARRIER))
1321                 seq_puts(seq, ",nobarrier");
1322         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1323                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1324         if (info->thread_pool_size !=  min_t(unsigned long,
1325                                              num_online_cpus() + 2, 8))
1326                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1327         if (btrfs_test_opt(info, COMPRESS)) {
1328                 compress_type = btrfs_compress_type2str(info->compress_type);
1329                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1330                         seq_printf(seq, ",compress-force=%s", compress_type);
1331                 else
1332                         seq_printf(seq, ",compress=%s", compress_type);
1333                 if (info->compress_level)
1334                         seq_printf(seq, ":%d", info->compress_level);
1335         }
1336         if (btrfs_test_opt(info, NOSSD))
1337                 seq_puts(seq, ",nossd");
1338         if (btrfs_test_opt(info, SSD_SPREAD))
1339                 seq_puts(seq, ",ssd_spread");
1340         else if (btrfs_test_opt(info, SSD))
1341                 seq_puts(seq, ",ssd");
1342         if (btrfs_test_opt(info, NOTREELOG))
1343                 seq_puts(seq, ",notreelog");
1344         if (btrfs_test_opt(info, NOLOGREPLAY))
1345                 seq_puts(seq, ",nologreplay");
1346         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1347                 seq_puts(seq, ",flushoncommit");
1348         if (btrfs_test_opt(info, DISCARD_SYNC))
1349                 seq_puts(seq, ",discard");
1350         if (btrfs_test_opt(info, DISCARD_ASYNC))
1351                 seq_puts(seq, ",discard=async");
1352         if (!(info->sb->s_flags & SB_POSIXACL))
1353                 seq_puts(seq, ",noacl");
1354         if (btrfs_test_opt(info, SPACE_CACHE))
1355                 seq_puts(seq, ",space_cache");
1356         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1357                 seq_puts(seq, ",space_cache=v2");
1358         else
1359                 seq_puts(seq, ",nospace_cache");
1360         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1361                 seq_puts(seq, ",rescan_uuid_tree");
1362         if (btrfs_test_opt(info, CLEAR_CACHE))
1363                 seq_puts(seq, ",clear_cache");
1364         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1365                 seq_puts(seq, ",user_subvol_rm_allowed");
1366         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1367                 seq_puts(seq, ",enospc_debug");
1368         if (btrfs_test_opt(info, AUTO_DEFRAG))
1369                 seq_puts(seq, ",autodefrag");
1370         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1371                 seq_puts(seq, ",inode_cache");
1372         if (btrfs_test_opt(info, SKIP_BALANCE))
1373                 seq_puts(seq, ",skip_balance");
1374 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1375         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1376                 seq_puts(seq, ",check_int_data");
1377         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1378                 seq_puts(seq, ",check_int");
1379         if (info->check_integrity_print_mask)
1380                 seq_printf(seq, ",check_int_print_mask=%d",
1381                                 info->check_integrity_print_mask);
1382 #endif
1383         if (info->metadata_ratio)
1384                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1385         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1386                 seq_puts(seq, ",fatal_errors=panic");
1387         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1388                 seq_printf(seq, ",commit=%u", info->commit_interval);
1389 #ifdef CONFIG_BTRFS_DEBUG
1390         if (btrfs_test_opt(info, FRAGMENT_DATA))
1391                 seq_puts(seq, ",fragment=data");
1392         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1393                 seq_puts(seq, ",fragment=metadata");
1394 #endif
1395         if (btrfs_test_opt(info, REF_VERIFY))
1396                 seq_puts(seq, ",ref_verify");
1397         seq_printf(seq, ",subvolid=%llu",
1398                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1399         seq_puts(seq, ",subvol=");
1400         seq_dentry(seq, dentry, " \t\n\\");
1401         return 0;
1402 }
1403
1404 static int btrfs_test_super(struct super_block *s, void *data)
1405 {
1406         struct btrfs_fs_info *p = data;
1407         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1408
1409         return fs_info->fs_devices == p->fs_devices;
1410 }
1411
1412 static int btrfs_set_super(struct super_block *s, void *data)
1413 {
1414         int err = set_anon_super(s, data);
1415         if (!err)
1416                 s->s_fs_info = data;
1417         return err;
1418 }
1419
1420 /*
1421  * subvolumes are identified by ino 256
1422  */
1423 static inline int is_subvolume_inode(struct inode *inode)
1424 {
1425         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1426                 return 1;
1427         return 0;
1428 }
1429
1430 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1431                                    struct vfsmount *mnt)
1432 {
1433         struct dentry *root;
1434         int ret;
1435
1436         if (!subvol_name) {
1437                 if (!subvol_objectid) {
1438                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1439                                                           &subvol_objectid);
1440                         if (ret) {
1441                                 root = ERR_PTR(ret);
1442                                 goto out;
1443                         }
1444                 }
1445                 subvol_name = btrfs_get_subvol_name_from_objectid(
1446                                         btrfs_sb(mnt->mnt_sb), subvol_objectid);
1447                 if (IS_ERR(subvol_name)) {
1448                         root = ERR_CAST(subvol_name);
1449                         subvol_name = NULL;
1450                         goto out;
1451                 }
1452
1453         }
1454
1455         root = mount_subtree(mnt, subvol_name);
1456         /* mount_subtree() drops our reference on the vfsmount. */
1457         mnt = NULL;
1458
1459         if (!IS_ERR(root)) {
1460                 struct super_block *s = root->d_sb;
1461                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1462                 struct inode *root_inode = d_inode(root);
1463                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1464
1465                 ret = 0;
1466                 if (!is_subvolume_inode(root_inode)) {
1467                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1468                                subvol_name);
1469                         ret = -EINVAL;
1470                 }
1471                 if (subvol_objectid && root_objectid != subvol_objectid) {
1472                         /*
1473                          * This will also catch a race condition where a
1474                          * subvolume which was passed by ID is renamed and
1475                          * another subvolume is renamed over the old location.
1476                          */
1477                         btrfs_err(fs_info,
1478                                   "subvol '%s' does not match subvolid %llu",
1479                                   subvol_name, subvol_objectid);
1480                         ret = -EINVAL;
1481                 }
1482                 if (ret) {
1483                         dput(root);
1484                         root = ERR_PTR(ret);
1485                         deactivate_locked_super(s);
1486                 }
1487         }
1488
1489 out:
1490         mntput(mnt);
1491         kfree(subvol_name);
1492         return root;
1493 }
1494
1495 /*
1496  * Find a superblock for the given device / mount point.
1497  *
1498  * Note: This is based on mount_bdev from fs/super.c with a few additions
1499  *       for multiple device setup.  Make sure to keep it in sync.
1500  */
1501 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1502                 int flags, const char *device_name, void *data)
1503 {
1504         struct block_device *bdev = NULL;
1505         struct super_block *s;
1506         struct btrfs_device *device = NULL;
1507         struct btrfs_fs_devices *fs_devices = NULL;
1508         struct btrfs_fs_info *fs_info = NULL;
1509         void *new_sec_opts = NULL;
1510         fmode_t mode = FMODE_READ;
1511         int error = 0;
1512
1513         if (!(flags & SB_RDONLY))
1514                 mode |= FMODE_WRITE;
1515
1516         if (data) {
1517                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1518                 if (error)
1519                         return ERR_PTR(error);
1520         }
1521
1522         /*
1523          * Setup a dummy root and fs_info for test/set super.  This is because
1524          * we don't actually fill this stuff out until open_ctree, but we need
1525          * then open_ctree will properly initialize the file system specific
1526          * settings later.  btrfs_init_fs_info initializes the static elements
1527          * of the fs_info (locks and such) to make cleanup easier if we find a
1528          * superblock with our given fs_devices later on at sget() time.
1529          */
1530         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1531         if (!fs_info) {
1532                 error = -ENOMEM;
1533                 goto error_sec_opts;
1534         }
1535         btrfs_init_fs_info(fs_info);
1536
1537         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1538         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1539         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1540                 error = -ENOMEM;
1541                 goto error_fs_info;
1542         }
1543
1544         mutex_lock(&uuid_mutex);
1545         error = btrfs_parse_device_options(data, mode, fs_type);
1546         if (error) {
1547                 mutex_unlock(&uuid_mutex);
1548                 goto error_fs_info;
1549         }
1550
1551         device = btrfs_scan_one_device(device_name, mode, fs_type);
1552         if (IS_ERR(device)) {
1553                 mutex_unlock(&uuid_mutex);
1554                 error = PTR_ERR(device);
1555                 goto error_fs_info;
1556         }
1557
1558         fs_devices = device->fs_devices;
1559         fs_info->fs_devices = fs_devices;
1560
1561         error = btrfs_open_devices(fs_devices, mode, fs_type);
1562         mutex_unlock(&uuid_mutex);
1563         if (error)
1564                 goto error_fs_info;
1565
1566         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1567                 error = -EACCES;
1568                 goto error_close_devices;
1569         }
1570
1571         bdev = fs_devices->latest_bdev;
1572         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1573                  fs_info);
1574         if (IS_ERR(s)) {
1575                 error = PTR_ERR(s);
1576                 goto error_close_devices;
1577         }
1578
1579         if (s->s_root) {
1580                 btrfs_close_devices(fs_devices);
1581                 btrfs_free_fs_info(fs_info);
1582                 if ((flags ^ s->s_flags) & SB_RDONLY)
1583                         error = -EBUSY;
1584         } else {
1585                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1586                 btrfs_sb(s)->bdev_holder = fs_type;
1587                 if (!strstr(crc32c_impl(), "generic"))
1588                         set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
1589                 error = btrfs_fill_super(s, fs_devices, data);
1590         }
1591         if (!error)
1592                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1593         security_free_mnt_opts(&new_sec_opts);
1594         if (error) {
1595                 deactivate_locked_super(s);
1596                 return ERR_PTR(error);
1597         }
1598
1599         return dget(s->s_root);
1600
1601 error_close_devices:
1602         btrfs_close_devices(fs_devices);
1603 error_fs_info:
1604         btrfs_free_fs_info(fs_info);
1605 error_sec_opts:
1606         security_free_mnt_opts(&new_sec_opts);
1607         return ERR_PTR(error);
1608 }
1609
1610 /*
1611  * Mount function which is called by VFS layer.
1612  *
1613  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1614  * which needs vfsmount* of device's root (/).  This means device's root has to
1615  * be mounted internally in any case.
1616  *
1617  * Operation flow:
1618  *   1. Parse subvol id related options for later use in mount_subvol().
1619  *
1620  *   2. Mount device's root (/) by calling vfs_kern_mount().
1621  *
1622  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1623  *      first place. In order to avoid calling btrfs_mount() again, we use
1624  *      different file_system_type which is not registered to VFS by
1625  *      register_filesystem() (btrfs_root_fs_type). As a result,
1626  *      btrfs_mount_root() is called. The return value will be used by
1627  *      mount_subtree() in mount_subvol().
1628  *
1629  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1630  *      "btrfs subvolume set-default", mount_subvol() is called always.
1631  */
1632 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1633                 const char *device_name, void *data)
1634 {
1635         struct vfsmount *mnt_root;
1636         struct dentry *root;
1637         char *subvol_name = NULL;
1638         u64 subvol_objectid = 0;
1639         int error = 0;
1640
1641         error = btrfs_parse_subvol_options(data, &subvol_name,
1642                                         &subvol_objectid);
1643         if (error) {
1644                 kfree(subvol_name);
1645                 return ERR_PTR(error);
1646         }
1647
1648         /* mount device's root (/) */
1649         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1650         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1651                 if (flags & SB_RDONLY) {
1652                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1653                                 flags & ~SB_RDONLY, device_name, data);
1654                 } else {
1655                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1656                                 flags | SB_RDONLY, device_name, data);
1657                         if (IS_ERR(mnt_root)) {
1658                                 root = ERR_CAST(mnt_root);
1659                                 kfree(subvol_name);
1660                                 goto out;
1661                         }
1662
1663                         down_write(&mnt_root->mnt_sb->s_umount);
1664                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1665                         up_write(&mnt_root->mnt_sb->s_umount);
1666                         if (error < 0) {
1667                                 root = ERR_PTR(error);
1668                                 mntput(mnt_root);
1669                                 kfree(subvol_name);
1670                                 goto out;
1671                         }
1672                 }
1673         }
1674         if (IS_ERR(mnt_root)) {
1675                 root = ERR_CAST(mnt_root);
1676                 kfree(subvol_name);
1677                 goto out;
1678         }
1679
1680         /* mount_subvol() will free subvol_name and mnt_root */
1681         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1682
1683 out:
1684         return root;
1685 }
1686
1687 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1688                                      u32 new_pool_size, u32 old_pool_size)
1689 {
1690         if (new_pool_size == old_pool_size)
1691                 return;
1692
1693         fs_info->thread_pool_size = new_pool_size;
1694
1695         btrfs_info(fs_info, "resize thread pool %d -> %d",
1696                old_pool_size, new_pool_size);
1697
1698         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1699         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1700         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1701         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1702         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1703         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1704                                 new_pool_size);
1705         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1706         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1707         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1708         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1709         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1710                                 new_pool_size);
1711 }
1712
1713 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1714 {
1715         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1716 }
1717
1718 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1719                                        unsigned long old_opts, int flags)
1720 {
1721         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1722             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1723              (flags & SB_RDONLY))) {
1724                 /* wait for any defraggers to finish */
1725                 wait_event(fs_info->transaction_wait,
1726                            (atomic_read(&fs_info->defrag_running) == 0));
1727                 if (flags & SB_RDONLY)
1728                         sync_filesystem(fs_info->sb);
1729         }
1730 }
1731
1732 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1733                                          unsigned long old_opts)
1734 {
1735         /*
1736          * We need to cleanup all defragable inodes if the autodefragment is
1737          * close or the filesystem is read only.
1738          */
1739         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1740             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1741                 btrfs_cleanup_defrag_inodes(fs_info);
1742         }
1743
1744         /* If we toggled discard async */
1745         if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1746             btrfs_test_opt(fs_info, DISCARD_ASYNC))
1747                 btrfs_discard_resume(fs_info);
1748         else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1749                  !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1750                 btrfs_discard_cleanup(fs_info);
1751
1752         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1753 }
1754
1755 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1756 {
1757         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1758         struct btrfs_root *root = fs_info->tree_root;
1759         unsigned old_flags = sb->s_flags;
1760         unsigned long old_opts = fs_info->mount_opt;
1761         unsigned long old_compress_type = fs_info->compress_type;
1762         u64 old_max_inline = fs_info->max_inline;
1763         u32 old_thread_pool_size = fs_info->thread_pool_size;
1764         u32 old_metadata_ratio = fs_info->metadata_ratio;
1765         int ret;
1766
1767         sync_filesystem(sb);
1768         btrfs_remount_prepare(fs_info);
1769
1770         if (data) {
1771                 void *new_sec_opts = NULL;
1772
1773                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1774                 if (!ret)
1775                         ret = security_sb_remount(sb, new_sec_opts);
1776                 security_free_mnt_opts(&new_sec_opts);
1777                 if (ret)
1778                         goto restore;
1779         }
1780
1781         ret = btrfs_parse_options(fs_info, data, *flags);
1782         if (ret)
1783                 goto restore;
1784
1785         btrfs_remount_begin(fs_info, old_opts, *flags);
1786         btrfs_resize_thread_pool(fs_info,
1787                 fs_info->thread_pool_size, old_thread_pool_size);
1788
1789         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1790                 goto out;
1791
1792         if (*flags & SB_RDONLY) {
1793                 /*
1794                  * this also happens on 'umount -rf' or on shutdown, when
1795                  * the filesystem is busy.
1796                  */
1797                 cancel_work_sync(&fs_info->async_reclaim_work);
1798
1799                 btrfs_discard_cleanup(fs_info);
1800
1801                 /* wait for the uuid_scan task to finish */
1802                 down(&fs_info->uuid_tree_rescan_sem);
1803                 /* avoid complains from lockdep et al. */
1804                 up(&fs_info->uuid_tree_rescan_sem);
1805
1806                 sb->s_flags |= SB_RDONLY;
1807
1808                 /*
1809                  * Setting SB_RDONLY will put the cleaner thread to
1810                  * sleep at the next loop if it's already active.
1811                  * If it's already asleep, we'll leave unused block
1812                  * groups on disk until we're mounted read-write again
1813                  * unless we clean them up here.
1814                  */
1815                 btrfs_delete_unused_bgs(fs_info);
1816
1817                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1818                 btrfs_scrub_cancel(fs_info);
1819                 btrfs_pause_balance(fs_info);
1820
1821                 ret = btrfs_commit_super(fs_info);
1822                 if (ret)
1823                         goto restore;
1824         } else {
1825                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1826                         btrfs_err(fs_info,
1827                                 "Remounting read-write after error is not allowed");
1828                         ret = -EINVAL;
1829                         goto restore;
1830                 }
1831                 if (fs_info->fs_devices->rw_devices == 0) {
1832                         ret = -EACCES;
1833                         goto restore;
1834                 }
1835
1836                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1837                         btrfs_warn(fs_info,
1838                 "too many missing devices, writable remount is not allowed");
1839                         ret = -EACCES;
1840                         goto restore;
1841                 }
1842
1843                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1844                         btrfs_warn(fs_info,
1845                 "mount required to replay tree-log, cannot remount read-write");
1846                         ret = -EINVAL;
1847                         goto restore;
1848                 }
1849
1850                 ret = btrfs_cleanup_fs_roots(fs_info);
1851                 if (ret)
1852                         goto restore;
1853
1854                 /* recover relocation */
1855                 mutex_lock(&fs_info->cleaner_mutex);
1856                 ret = btrfs_recover_relocation(root);
1857                 mutex_unlock(&fs_info->cleaner_mutex);
1858                 if (ret)
1859                         goto restore;
1860
1861                 ret = btrfs_resume_balance_async(fs_info);
1862                 if (ret)
1863                         goto restore;
1864
1865                 ret = btrfs_resume_dev_replace_async(fs_info);
1866                 if (ret) {
1867                         btrfs_warn(fs_info, "failed to resume dev_replace");
1868                         goto restore;
1869                 }
1870
1871                 btrfs_qgroup_rescan_resume(fs_info);
1872
1873                 if (!fs_info->uuid_root) {
1874                         btrfs_info(fs_info, "creating UUID tree");
1875                         ret = btrfs_create_uuid_tree(fs_info);
1876                         if (ret) {
1877                                 btrfs_warn(fs_info,
1878                                            "failed to create the UUID tree %d",
1879                                            ret);
1880                                 goto restore;
1881                         }
1882                 }
1883                 sb->s_flags &= ~SB_RDONLY;
1884
1885                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1886         }
1887 out:
1888         wake_up_process(fs_info->transaction_kthread);
1889         btrfs_remount_cleanup(fs_info, old_opts);
1890         return 0;
1891
1892 restore:
1893         /* We've hit an error - don't reset SB_RDONLY */
1894         if (sb_rdonly(sb))
1895                 old_flags |= SB_RDONLY;
1896         sb->s_flags = old_flags;
1897         fs_info->mount_opt = old_opts;
1898         fs_info->compress_type = old_compress_type;
1899         fs_info->max_inline = old_max_inline;
1900         btrfs_resize_thread_pool(fs_info,
1901                 old_thread_pool_size, fs_info->thread_pool_size);
1902         fs_info->metadata_ratio = old_metadata_ratio;
1903         btrfs_remount_cleanup(fs_info, old_opts);
1904         return ret;
1905 }
1906
1907 /* Used to sort the devices by max_avail(descending sort) */
1908 static inline int btrfs_cmp_device_free_bytes(const void *dev_info1,
1909                                        const void *dev_info2)
1910 {
1911         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1912             ((struct btrfs_device_info *)dev_info2)->max_avail)
1913                 return -1;
1914         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1915                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1916                 return 1;
1917         else
1918         return 0;
1919 }
1920
1921 /*
1922  * sort the devices by max_avail, in which max free extent size of each device
1923  * is stored.(Descending Sort)
1924  */
1925 static inline void btrfs_descending_sort_devices(
1926                                         struct btrfs_device_info *devices,
1927                                         size_t nr_devices)
1928 {
1929         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1930              btrfs_cmp_device_free_bytes, NULL);
1931 }
1932
1933 /*
1934  * The helper to calc the free space on the devices that can be used to store
1935  * file data.
1936  */
1937 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1938                                               u64 *free_bytes)
1939 {
1940         struct btrfs_device_info *devices_info;
1941         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1942         struct btrfs_device *device;
1943         u64 type;
1944         u64 avail_space;
1945         u64 min_stripe_size;
1946         int num_stripes = 1;
1947         int i = 0, nr_devices;
1948         const struct btrfs_raid_attr *rattr;
1949
1950         /*
1951          * We aren't under the device list lock, so this is racy-ish, but good
1952          * enough for our purposes.
1953          */
1954         nr_devices = fs_info->fs_devices->open_devices;
1955         if (!nr_devices) {
1956                 smp_mb();
1957                 nr_devices = fs_info->fs_devices->open_devices;
1958                 ASSERT(nr_devices);
1959                 if (!nr_devices) {
1960                         *free_bytes = 0;
1961                         return 0;
1962                 }
1963         }
1964
1965         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1966                                GFP_KERNEL);
1967         if (!devices_info)
1968                 return -ENOMEM;
1969
1970         /* calc min stripe number for data space allocation */
1971         type = btrfs_data_alloc_profile(fs_info);
1972         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1973
1974         if (type & BTRFS_BLOCK_GROUP_RAID0)
1975                 num_stripes = nr_devices;
1976         else if (type & BTRFS_BLOCK_GROUP_RAID1)
1977                 num_stripes = 2;
1978         else if (type & BTRFS_BLOCK_GROUP_RAID1C3)
1979                 num_stripes = 3;
1980         else if (type & BTRFS_BLOCK_GROUP_RAID1C4)
1981                 num_stripes = 4;
1982         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1983                 num_stripes = 4;
1984
1985         /* Adjust for more than 1 stripe per device */
1986         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1987
1988         rcu_read_lock();
1989         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1990                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1991                                                 &device->dev_state) ||
1992                     !device->bdev ||
1993                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1994                         continue;
1995
1996                 if (i >= nr_devices)
1997                         break;
1998
1999                 avail_space = device->total_bytes - device->bytes_used;
2000
2001                 /* align with stripe_len */
2002                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
2003
2004                 /*
2005                  * In order to avoid overwriting the superblock on the drive,
2006                  * btrfs starts at an offset of at least 1MB when doing chunk
2007                  * allocation.
2008                  *
2009                  * This ensures we have at least min_stripe_size free space
2010                  * after excluding 1MB.
2011                  */
2012                 if (avail_space <= SZ_1M + min_stripe_size)
2013                         continue;
2014
2015                 avail_space -= SZ_1M;
2016
2017                 devices_info[i].dev = device;
2018                 devices_info[i].max_avail = avail_space;
2019
2020                 i++;
2021         }
2022         rcu_read_unlock();
2023
2024         nr_devices = i;
2025
2026         btrfs_descending_sort_devices(devices_info, nr_devices);
2027
2028         i = nr_devices - 1;
2029         avail_space = 0;
2030         while (nr_devices >= rattr->devs_min) {
2031                 num_stripes = min(num_stripes, nr_devices);
2032
2033                 if (devices_info[i].max_avail >= min_stripe_size) {
2034                         int j;
2035                         u64 alloc_size;
2036
2037                         avail_space += devices_info[i].max_avail * num_stripes;
2038                         alloc_size = devices_info[i].max_avail;
2039                         for (j = i + 1 - num_stripes; j <= i; j++)
2040                                 devices_info[j].max_avail -= alloc_size;
2041                 }
2042                 i--;
2043                 nr_devices--;
2044         }
2045
2046         kfree(devices_info);
2047         *free_bytes = avail_space;
2048         return 0;
2049 }
2050
2051 /*
2052  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2053  *
2054  * If there's a redundant raid level at DATA block groups, use the respective
2055  * multiplier to scale the sizes.
2056  *
2057  * Unused device space usage is based on simulating the chunk allocator
2058  * algorithm that respects the device sizes and order of allocations.  This is
2059  * a close approximation of the actual use but there are other factors that may
2060  * change the result (like a new metadata chunk).
2061  *
2062  * If metadata is exhausted, f_bavail will be 0.
2063  */
2064 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2065 {
2066         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2067         struct btrfs_super_block *disk_super = fs_info->super_copy;
2068         struct btrfs_space_info *found;
2069         u64 total_used = 0;
2070         u64 total_free_data = 0;
2071         u64 total_free_meta = 0;
2072         int bits = dentry->d_sb->s_blocksize_bits;
2073         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2074         unsigned factor = 1;
2075         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2076         int ret;
2077         u64 thresh = 0;
2078         int mixed = 0;
2079
2080         rcu_read_lock();
2081         list_for_each_entry_rcu(found, &fs_info->space_info, list) {
2082                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2083                         int i;
2084
2085                         total_free_data += found->disk_total - found->disk_used;
2086                         total_free_data -=
2087                                 btrfs_account_ro_block_groups_free_space(found);
2088
2089                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2090                                 if (!list_empty(&found->block_groups[i]))
2091                                         factor = btrfs_bg_type_to_factor(
2092                                                 btrfs_raid_array[i].bg_flag);
2093                         }
2094                 }
2095
2096                 /*
2097                  * Metadata in mixed block goup profiles are accounted in data
2098                  */
2099                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2100                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2101                                 mixed = 1;
2102                         else
2103                                 total_free_meta += found->disk_total -
2104                                         found->disk_used;
2105                 }
2106
2107                 total_used += found->disk_used;
2108         }
2109
2110         rcu_read_unlock();
2111
2112         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2113         buf->f_blocks >>= bits;
2114         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2115
2116         /* Account global block reserve as used, it's in logical size already */
2117         spin_lock(&block_rsv->lock);
2118         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2119         if (buf->f_bfree >= block_rsv->size >> bits)
2120                 buf->f_bfree -= block_rsv->size >> bits;
2121         else
2122                 buf->f_bfree = 0;
2123         spin_unlock(&block_rsv->lock);
2124
2125         buf->f_bavail = div_u64(total_free_data, factor);
2126         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2127         if (ret)
2128                 return ret;
2129         buf->f_bavail += div_u64(total_free_data, factor);
2130         buf->f_bavail = buf->f_bavail >> bits;
2131
2132         /*
2133          * We calculate the remaining metadata space minus global reserve. If
2134          * this is (supposedly) smaller than zero, there's no space. But this
2135          * does not hold in practice, the exhausted state happens where's still
2136          * some positive delta. So we apply some guesswork and compare the
2137          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2138          *
2139          * We probably cannot calculate the exact threshold value because this
2140          * depends on the internal reservations requested by various
2141          * operations, so some operations that consume a few metadata will
2142          * succeed even if the Avail is zero. But this is better than the other
2143          * way around.
2144          */
2145         thresh = SZ_4M;
2146
2147         /*
2148          * We only want to claim there's no available space if we can no longer
2149          * allocate chunks for our metadata profile and our global reserve will
2150          * not fit in the free metadata space.  If we aren't ->full then we
2151          * still can allocate chunks and thus are fine using the currently
2152          * calculated f_bavail.
2153          */
2154         if (!mixed && block_rsv->space_info->full &&
2155             total_free_meta - thresh < block_rsv->size)
2156                 buf->f_bavail = 0;
2157
2158         buf->f_type = BTRFS_SUPER_MAGIC;
2159         buf->f_bsize = dentry->d_sb->s_blocksize;
2160         buf->f_namelen = BTRFS_NAME_LEN;
2161
2162         /* We treat it as constant endianness (it doesn't matter _which_)
2163            because we want the fsid to come out the same whether mounted
2164            on a big-endian or little-endian host */
2165         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2166         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2167         /* Mask in the root object ID too, to disambiguate subvols */
2168         buf->f_fsid.val[0] ^=
2169                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2170         buf->f_fsid.val[1] ^=
2171                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2172
2173         return 0;
2174 }
2175
2176 static void btrfs_kill_super(struct super_block *sb)
2177 {
2178         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2179         kill_anon_super(sb);
2180         btrfs_free_fs_info(fs_info);
2181 }
2182
2183 static struct file_system_type btrfs_fs_type = {
2184         .owner          = THIS_MODULE,
2185         .name           = "btrfs",
2186         .mount          = btrfs_mount,
2187         .kill_sb        = btrfs_kill_super,
2188         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2189 };
2190
2191 static struct file_system_type btrfs_root_fs_type = {
2192         .owner          = THIS_MODULE,
2193         .name           = "btrfs",
2194         .mount          = btrfs_mount_root,
2195         .kill_sb        = btrfs_kill_super,
2196         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2197 };
2198
2199 MODULE_ALIAS_FS("btrfs");
2200
2201 static int btrfs_control_open(struct inode *inode, struct file *file)
2202 {
2203         /*
2204          * The control file's private_data is used to hold the
2205          * transaction when it is started and is used to keep
2206          * track of whether a transaction is already in progress.
2207          */
2208         file->private_data = NULL;
2209         return 0;
2210 }
2211
2212 /*
2213  * Used by /dev/btrfs-control for devices ioctls.
2214  */
2215 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2216                                 unsigned long arg)
2217 {
2218         struct btrfs_ioctl_vol_args *vol;
2219         struct btrfs_device *device = NULL;
2220         int ret = -ENOTTY;
2221
2222         if (!capable(CAP_SYS_ADMIN))
2223                 return -EPERM;
2224
2225         vol = memdup_user((void __user *)arg, sizeof(*vol));
2226         if (IS_ERR(vol))
2227                 return PTR_ERR(vol);
2228         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2229
2230         switch (cmd) {
2231         case BTRFS_IOC_SCAN_DEV:
2232                 mutex_lock(&uuid_mutex);
2233                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2234                                                &btrfs_root_fs_type);
2235                 ret = PTR_ERR_OR_ZERO(device);
2236                 mutex_unlock(&uuid_mutex);
2237                 break;
2238         case BTRFS_IOC_FORGET_DEV:
2239                 ret = btrfs_forget_devices(vol->name);
2240                 break;
2241         case BTRFS_IOC_DEVICES_READY:
2242                 mutex_lock(&uuid_mutex);
2243                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2244                                                &btrfs_root_fs_type);
2245                 if (IS_ERR(device)) {
2246                         mutex_unlock(&uuid_mutex);
2247                         ret = PTR_ERR(device);
2248                         break;
2249                 }
2250                 ret = !(device->fs_devices->num_devices ==
2251                         device->fs_devices->total_devices);
2252                 mutex_unlock(&uuid_mutex);
2253                 break;
2254         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2255                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2256                 break;
2257         }
2258
2259         kfree(vol);
2260         return ret;
2261 }
2262
2263 static int btrfs_freeze(struct super_block *sb)
2264 {
2265         struct btrfs_trans_handle *trans;
2266         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2267         struct btrfs_root *root = fs_info->tree_root;
2268
2269         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2270         /*
2271          * We don't need a barrier here, we'll wait for any transaction that
2272          * could be in progress on other threads (and do delayed iputs that
2273          * we want to avoid on a frozen filesystem), or do the commit
2274          * ourselves.
2275          */
2276         trans = btrfs_attach_transaction_barrier(root);
2277         if (IS_ERR(trans)) {
2278                 /* no transaction, don't bother */
2279                 if (PTR_ERR(trans) == -ENOENT)
2280                         return 0;
2281                 return PTR_ERR(trans);
2282         }
2283         return btrfs_commit_transaction(trans);
2284 }
2285
2286 static int btrfs_unfreeze(struct super_block *sb)
2287 {
2288         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2289
2290         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2291         return 0;
2292 }
2293
2294 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2295 {
2296         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2297         struct btrfs_fs_devices *cur_devices;
2298         struct btrfs_device *dev, *first_dev = NULL;
2299         struct list_head *head;
2300
2301         /*
2302          * Lightweight locking of the devices. We should not need
2303          * device_list_mutex here as we only read the device data and the list
2304          * is protected by RCU.  Even if a device is deleted during the list
2305          * traversals, we'll get valid data, the freeing callback will wait at
2306          * least until the rcu_read_unlock.
2307          */
2308         rcu_read_lock();
2309         cur_devices = fs_info->fs_devices;
2310         while (cur_devices) {
2311                 head = &cur_devices->devices;
2312                 list_for_each_entry_rcu(dev, head, dev_list) {
2313                         if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
2314                                 continue;
2315                         if (!dev->name)
2316                                 continue;
2317                         if (!first_dev || dev->devid < first_dev->devid)
2318                                 first_dev = dev;
2319                 }
2320                 cur_devices = cur_devices->seed;
2321         }
2322
2323         if (first_dev)
2324                 seq_escape(m, rcu_str_deref(first_dev->name), " \t\n\\");
2325         else
2326                 WARN_ON(1);
2327         rcu_read_unlock();
2328         return 0;
2329 }
2330
2331 static const struct super_operations btrfs_super_ops = {
2332         .drop_inode     = btrfs_drop_inode,
2333         .evict_inode    = btrfs_evict_inode,
2334         .put_super      = btrfs_put_super,
2335         .sync_fs        = btrfs_sync_fs,
2336         .show_options   = btrfs_show_options,
2337         .show_devname   = btrfs_show_devname,
2338         .alloc_inode    = btrfs_alloc_inode,
2339         .destroy_inode  = btrfs_destroy_inode,
2340         .free_inode     = btrfs_free_inode,
2341         .statfs         = btrfs_statfs,
2342         .remount_fs     = btrfs_remount,
2343         .freeze_fs      = btrfs_freeze,
2344         .unfreeze_fs    = btrfs_unfreeze,
2345 };
2346
2347 static const struct file_operations btrfs_ctl_fops = {
2348         .open = btrfs_control_open,
2349         .unlocked_ioctl  = btrfs_control_ioctl,
2350         .compat_ioctl = compat_ptr_ioctl,
2351         .owner   = THIS_MODULE,
2352         .llseek = noop_llseek,
2353 };
2354
2355 static struct miscdevice btrfs_misc = {
2356         .minor          = BTRFS_MINOR,
2357         .name           = "btrfs-control",
2358         .fops           = &btrfs_ctl_fops
2359 };
2360
2361 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2362 MODULE_ALIAS("devname:btrfs-control");
2363
2364 static int __init btrfs_interface_init(void)
2365 {
2366         return misc_register(&btrfs_misc);
2367 }
2368
2369 static __cold void btrfs_interface_exit(void)
2370 {
2371         misc_deregister(&btrfs_misc);
2372 }
2373
2374 static void __init btrfs_print_mod_info(void)
2375 {
2376         static const char options[] = ""
2377 #ifdef CONFIG_BTRFS_DEBUG
2378                         ", debug=on"
2379 #endif
2380 #ifdef CONFIG_BTRFS_ASSERT
2381                         ", assert=on"
2382 #endif
2383 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2384                         ", integrity-checker=on"
2385 #endif
2386 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2387                         ", ref-verify=on"
2388 #endif
2389                         ;
2390         pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
2391 }
2392
2393 static int __init init_btrfs_fs(void)
2394 {
2395         int err;
2396
2397         btrfs_props_init();
2398
2399         err = btrfs_init_sysfs();
2400         if (err)
2401                 return err;
2402
2403         btrfs_init_compress();
2404
2405         err = btrfs_init_cachep();
2406         if (err)
2407                 goto free_compress;
2408
2409         err = extent_io_init();
2410         if (err)
2411                 goto free_cachep;
2412
2413         err = extent_state_cache_init();
2414         if (err)
2415                 goto free_extent_io;
2416
2417         err = extent_map_init();
2418         if (err)
2419                 goto free_extent_state_cache;
2420
2421         err = ordered_data_init();
2422         if (err)
2423                 goto free_extent_map;
2424
2425         err = btrfs_delayed_inode_init();
2426         if (err)
2427                 goto free_ordered_data;
2428
2429         err = btrfs_auto_defrag_init();
2430         if (err)
2431                 goto free_delayed_inode;
2432
2433         err = btrfs_delayed_ref_init();
2434         if (err)
2435                 goto free_auto_defrag;
2436
2437         err = btrfs_prelim_ref_init();
2438         if (err)
2439                 goto free_delayed_ref;
2440
2441         err = btrfs_end_io_wq_init();
2442         if (err)
2443                 goto free_prelim_ref;
2444
2445         err = btrfs_interface_init();
2446         if (err)
2447                 goto free_end_io_wq;
2448
2449         btrfs_init_lockdep();
2450
2451         btrfs_print_mod_info();
2452
2453         err = btrfs_run_sanity_tests();
2454         if (err)
2455                 goto unregister_ioctl;
2456
2457         err = register_filesystem(&btrfs_fs_type);
2458         if (err)
2459                 goto unregister_ioctl;
2460
2461         return 0;
2462
2463 unregister_ioctl:
2464         btrfs_interface_exit();
2465 free_end_io_wq:
2466         btrfs_end_io_wq_exit();
2467 free_prelim_ref:
2468         btrfs_prelim_ref_exit();
2469 free_delayed_ref:
2470         btrfs_delayed_ref_exit();
2471 free_auto_defrag:
2472         btrfs_auto_defrag_exit();
2473 free_delayed_inode:
2474         btrfs_delayed_inode_exit();
2475 free_ordered_data:
2476         ordered_data_exit();
2477 free_extent_map:
2478         extent_map_exit();
2479 free_extent_state_cache:
2480         extent_state_cache_exit();
2481 free_extent_io:
2482         extent_io_exit();
2483 free_cachep:
2484         btrfs_destroy_cachep();
2485 free_compress:
2486         btrfs_exit_compress();
2487         btrfs_exit_sysfs();
2488
2489         return err;
2490 }
2491
2492 static void __exit exit_btrfs_fs(void)
2493 {
2494         btrfs_destroy_cachep();
2495         btrfs_delayed_ref_exit();
2496         btrfs_auto_defrag_exit();
2497         btrfs_delayed_inode_exit();
2498         btrfs_prelim_ref_exit();
2499         ordered_data_exit();
2500         extent_map_exit();
2501         extent_state_cache_exit();
2502         extent_io_exit();
2503         btrfs_interface_exit();
2504         btrfs_end_io_wq_exit();
2505         unregister_filesystem(&btrfs_fs_type);
2506         btrfs_exit_sysfs();
2507         btrfs_cleanup_fs_uuids();
2508         btrfs_exit_compress();
2509 }
2510
2511 late_initcall(init_btrfs_fs);
2512 module_exit(exit_btrfs_fs)
2513
2514 MODULE_LICENSE("GPL");
2515 MODULE_SOFTDEP("pre: crc32c");
2516 MODULE_SOFTDEP("pre: xxhash64");
2517 MODULE_SOFTDEP("pre: sha256");
2518 MODULE_SOFTDEP("pre: blake2b-256");