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
  50 #include "qgroup.h"
  51 #define CREATE_TRACE_POINTS
  52 #include <trace/events/btrfs.h>
  53
  54 static const struct super_operations btrfs_super_ops;
  55
  56 /*
  57  * Types for mounting the default subvolume and a subvolume explicitly
  58  * requested by subvol=/path. That way the callchain is straightforward and we
  59  * don't have to play tricks with the mount options and recursive calls to
  60  * btrfs_mount.
  61  *
  62  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
  63  */
  64 static struct file_system_type btrfs_fs_type;
  65 static struct file_system_type btrfs_root_fs_type;
  66
  67 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  68
  69 const char *btrfs_decode_error(int errno)
  70 {
  71         char *errstr = "unknown";
  72
  73         switch (errno) {
  74         case -EIO:
  75                 errstr = "IO failure";
  76                 break;
  77         case -ENOMEM:
  78                 errstr = "Out of memory";
  79                 break;
  80         case -EROFS:
  81                 errstr = "Readonly filesystem";
  82                 break;
  83         case -EEXIST:
  84                 errstr = "Object already exists";
  85                 break;
  86         case -ENOSPC:
  87                 errstr = "No space left";
  88                 break;
  89         case -ENOENT:
  90                 errstr = "No such entry";
  91                 break;
  92         }
  93
  94         return errstr;
  95 }
  96
  97 /*
  98  * __btrfs_handle_fs_error decodes expected errors from the caller and
  99  * invokes the appropriate error response.
 100  */
 101 __cold
 102 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 103                        unsigned int line, int errno, const char *fmt, ...)
 104 {
 105         struct super_block *sb = fs_info->sb;
 106 #ifdef CONFIG_PRINTK
 107         const char *errstr;
 108 #endif
 109
 110         /*
 111          * Special case: if the error is EROFS, and we're already
 112          * under SB_RDONLY, then it is safe here.
 113          */
 114         if (errno == -EROFS && sb_rdonly(sb))
 115                 return;
 116
 117 #ifdef CONFIG_PRINTK
 118         errstr = btrfs_decode_error(errno);
 119         if (fmt) {
 120                 struct va_format vaf;
 121                 va_list args;
 122
 123                 va_start(args, fmt);
 124                 vaf.fmt = fmt;
 125                 vaf.va = &args;
 126
 127                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 128                         sb->s_id, function, line, errno, errstr, &vaf);
 129                 va_end(args);
 130         } else {
 131                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 132                         sb->s_id, function, line, errno, errstr);
 133         }
 134 #endif
 135
 136         /*
 137          * Today we only save the error info to memory.  Long term we'll
 138          * also send it down to the disk
 139          */
 140         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 141
 142         /* Don't go through full error handling during mount */
 143         if (!(sb->s_flags & SB_BORN))
 144                 return;
 145
 146         if (sb_rdonly(sb))
 147                 return;
 148
 149         /* btrfs handle error by forcing the filesystem readonly */
 150         sb->s_flags |= SB_RDONLY;
 151         btrfs_info(fs_info, "forced readonly");
 152         /*
 153          * Note that a running device replace operation is not canceled here
 154          * although there is no way to update the progress. It would add the
 155          * risk of a deadlock, therefore the canceling is omitted. The only
 156          * penalty is that some I/O remains active until the procedure
 157          * completes. The next time when the filesystem is mounted writable
 158          * again, the device replace operation continues.
 159          */
 160 }
 161
 162 #ifdef CONFIG_PRINTK
 163 static const char * const logtypes[] = {
 164         "emergency",
 165         "alert",
 166         "critical",
 167         "error",
 168         "warning",
 169         "notice",
 170         "info",
 171         "debug",
 172 };
 173
 174
 175 /*
 176  * Use one ratelimit state per log level so that a flood of less important
 177  * messages doesn't cause more important ones to be dropped.
 178  */
 179 static struct ratelimit_state printk_limits[] = {
 180         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 181         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 182         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 183         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 184         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 185         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 186         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 187         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 188 };
 189
 190 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 191 {
 192         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
 193         struct va_format vaf;
 194         va_list args;
 195         int kern_level;
 196         const char *type = logtypes[4];
 197         struct ratelimit_state *ratelimit = &printk_limits[4];
 198
 199         va_start(args, fmt);
 200
 201         while ((kern_level = printk_get_level(fmt)) != 0) {
 202                 size_t size = printk_skip_level(fmt) - fmt;
 203
 204                 if (kern_level >= '0' && kern_level <= '7') {
 205                         memcpy(lvl, fmt,  size);
 206                         lvl[size] = '\0';
 207                         type = logtypes[kern_level - '0'];
 208                         ratelimit = &printk_limits[kern_level - '0'];
 209                 }
 210                 fmt += size;
 211         }
 212
 213         vaf.fmt = fmt;
 214         vaf.va = &args;
 215
 216         if (__ratelimit(ratelimit))
 217                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type,
 218                         fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);
 219
 220         va_end(args);
 221 }
 222 #endif
 223
 224 /*
 225  * We only mark the transaction aborted and then set the file system read-only.
 226  * This will prevent new transactions from starting or trying to join this
 227  * one.
 228  *
 229  * This means that error recovery at the call site is limited to freeing
 230  * any local memory allocations and passing the error code up without
 231  * further cleanup. The transaction should complete as it normally would
 232  * in the call path but will return -EIO.
 233  *
 234  * We'll complete the cleanup in btrfs_end_transaction and
 235  * btrfs_commit_transaction.
 236  */
 237 __cold
 238 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 239                                const char *function,
 240                                unsigned int line, int errno)
 241 {
 242         struct btrfs_fs_info *fs_info = trans->fs_info;
 243
 244         trans->aborted = errno;
 245         /* Nothing used. The other threads that have joined this
 246          * transaction may be able to continue. */
 247         if (!trans->dirty && list_empty(&trans->new_bgs)) {
 248                 const char *errstr;
 249
 250                 errstr = btrfs_decode_error(errno);
 251                 btrfs_warn(fs_info,
 252                            "%s:%d: Aborting unused transaction(%s).",
 253                            function, line, errstr);
 254                 return;
 255         }
 256         WRITE_ONCE(trans->transaction->aborted, errno);
 257         /* Wake up anybody who may be waiting on this transaction */
 258         wake_up(&fs_info->transaction_wait);
 259         wake_up(&fs_info->transaction_blocked_wait);
 260         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 261 }
 262 /*
 263  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 264  * issues an alert, and either panics or BUGs, depending on mount options.
 265  */
 266 __cold
 267 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 268                    unsigned int line, int errno, const char *fmt, ...)
 269 {
 270         char *s_id = "<unknown>";
 271         const char *errstr;
 272         struct va_format vaf = { .fmt = fmt };
 273         va_list args;
 274
 275         if (fs_info)
 276                 s_id = fs_info->sb->s_id;
 277
 278         va_start(args, fmt);
 279         vaf.va = &args;
 280
 281         errstr = btrfs_decode_error(errno);
 282         if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
 283                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 284                         s_id, function, line, &vaf, errno, errstr);
 285
 286         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 287                    function, line, &vaf, errno, errstr);
 288         va_end(args);
 289         /* Caller calls BUG() */
 290 }
 291
 292 static void btrfs_put_super(struct super_block *sb)
 293 {
 294         close_ctree(btrfs_sb(sb));
 295 }
 296
 297 enum {
 298         Opt_acl, Opt_noacl,
 299         Opt_clear_cache,
 300         Opt_commit_interval,
 301         Opt_compress,
 302         Opt_compress_force,
 303         Opt_compress_force_type,
 304         Opt_compress_type,
 305         Opt_degraded,
 306         Opt_device,
 307         Opt_fatal_errors,
 308         Opt_flushoncommit, Opt_noflushoncommit,
 309         Opt_inode_cache, Opt_noinode_cache,
 310         Opt_max_inline,
 311         Opt_barrier, Opt_nobarrier,
 312         Opt_datacow, Opt_nodatacow,
 313         Opt_datasum, Opt_nodatasum,
 314         Opt_defrag, Opt_nodefrag,
 315         Opt_discard, Opt_nodiscard,
 316         Opt_nologreplay,
 317         Opt_norecovery,
 318         Opt_ratio,
 319         Opt_rescan_uuid_tree,
 320         Opt_skip_balance,
 321         Opt_space_cache, Opt_no_space_cache,
 322         Opt_space_cache_version,
 323         Opt_ssd, Opt_nossd,
 324         Opt_ssd_spread, Opt_nossd_spread,
 325         Opt_subvol,
 326         Opt_subvol_empty,
 327         Opt_subvolid,
 328         Opt_thread_pool,
 329         Opt_treelog, Opt_notreelog,
 330         Opt_usebackuproot,
 331         Opt_user_subvol_rm_allowed,
 332
 333         /* Deprecated options */
 334         Opt_alloc_start,
 335         Opt_recovery,
 336         Opt_subvolrootid,
 337
 338         /* Debugging options */
 339         Opt_check_integrity,
 340         Opt_check_integrity_including_extent_data,
 341         Opt_check_integrity_print_mask,
 342         Opt_enospc_debug, Opt_noenospc_debug,
 343 #ifdef CONFIG_BTRFS_DEBUG
 344         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 345 #endif
 346 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 347         Opt_ref_verify,
 348 #endif
 349         Opt_err,
 350 };
 351
 352 static const match_table_t tokens = {
 353         {Opt_acl, "acl"},
 354         {Opt_noacl, "noacl"},
 355         {Opt_clear_cache, "clear_cache"},
 356         {Opt_commit_interval, "commit=%u"},
 357         {Opt_compress, "compress"},
 358         {Opt_compress_type, "compress=%s"},
 359         {Opt_compress_force, "compress-force"},
 360         {Opt_compress_force_type, "compress-force=%s"},
 361         {Opt_degraded, "degraded"},
 362         {Opt_device, "device=%s"},
 363         {Opt_fatal_errors, "fatal_errors=%s"},
 364         {Opt_flushoncommit, "flushoncommit"},
 365         {Opt_noflushoncommit, "noflushoncommit"},
 366         {Opt_inode_cache, "inode_cache"},
 367         {Opt_noinode_cache, "noinode_cache"},
 368         {Opt_max_inline, "max_inline=%s"},
 369         {Opt_barrier, "barrier"},
 370         {Opt_nobarrier, "nobarrier"},
 371         {Opt_datacow, "datacow"},
 372         {Opt_nodatacow, "nodatacow"},
 373         {Opt_datasum, "datasum"},
 374         {Opt_nodatasum, "nodatasum"},
 375         {Opt_defrag, "autodefrag"},
 376         {Opt_nodefrag, "noautodefrag"},
 377         {Opt_discard, "discard"},
 378         {Opt_nodiscard, "nodiscard"},
 379         {Opt_nologreplay, "nologreplay"},
 380         {Opt_norecovery, "norecovery"},
 381         {Opt_ratio, "metadata_ratio=%u"},
 382         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 383         {Opt_skip_balance, "skip_balance"},
 384         {Opt_space_cache, "space_cache"},
 385         {Opt_no_space_cache, "nospace_cache"},
 386         {Opt_space_cache_version, "space_cache=%s"},
 387         {Opt_ssd, "ssd"},
 388         {Opt_nossd, "nossd"},
 389         {Opt_ssd_spread, "ssd_spread"},
 390         {Opt_nossd_spread, "nossd_spread"},
 391         {Opt_subvol, "subvol=%s"},
 392         {Opt_subvol_empty, "subvol="},
 393         {Opt_subvolid, "subvolid=%s"},
 394         {Opt_thread_pool, "thread_pool=%u"},
 395         {Opt_treelog, "treelog"},
 396         {Opt_notreelog, "notreelog"},
 397         {Opt_usebackuproot, "usebackuproot"},
 398         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 399
 400         /* Deprecated options */
 401         {Opt_alloc_start, "alloc_start=%s"},
 402         {Opt_recovery, "recovery"},
 403         {Opt_subvolrootid, "subvolrootid=%d"},
 404
 405         /* Debugging options */
 406         {Opt_check_integrity, "check_int"},
 407         {Opt_check_integrity_including_extent_data, "check_int_data"},
 408         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
 409         {Opt_enospc_debug, "enospc_debug"},
 410         {Opt_noenospc_debug, "noenospc_debug"},
 411 #ifdef CONFIG_BTRFS_DEBUG
 412         {Opt_fragment_data, "fragment=data"},
 413         {Opt_fragment_metadata, "fragment=metadata"},
 414         {Opt_fragment_all, "fragment=all"},
 415 #endif
 416 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 417         {Opt_ref_verify, "ref_verify"},
 418 #endif
 419         {Opt_err, NULL},
 420 };
 421
 422 /*
 423  * Regular mount options parser.  Everything that is needed only when
 424  * reading in a new superblock is parsed here.
 425  * XXX JDM: This needs to be cleaned up for remount.
 426  */
 427 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 428                         unsigned long new_flags)
 429 {
 430         substring_t args[MAX_OPT_ARGS];
 431         char *p, *num;
 432         u64 cache_gen;
 433         int intarg;
 434         int ret = 0;
 435         char *compress_type;
 436         bool compress_force = false;
 437         enum btrfs_compression_type saved_compress_type;
 438         bool saved_compress_force;
 439         int no_compress = 0;
 440
 441         cache_gen = btrfs_super_cache_generation(info->super_copy);
 442         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 443                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 444         else if (cache_gen)
 445                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 446
 447         /*
 448          * Even the options are empty, we still need to do extra check
 449          * against new flags
 450          */
 451         if (!options)
 452                 goto check;
 453
 454         while ((p = strsep(&options, ",")) != NULL) {
 455                 int token;
 456                 if (!*p)
 457                         continue;
 458
 459                 token = match_token(p, tokens, args);
 460                 switch (token) {
 461                 case Opt_degraded:
 462                         btrfs_info(info, "allowing degraded mounts");
 463                         btrfs_set_opt(info->mount_opt, DEGRADED);
 464                         break;
 465                 case Opt_subvol:
 466                 case Opt_subvol_empty:
 467                 case Opt_subvolid:
 468                 case Opt_subvolrootid:
 469                 case Opt_device:
 470                         /*
 471                          * These are parsed by btrfs_parse_subvol_options or
 472                          * btrfs_parse_device_options and can be ignored here.
 473                          */
 474                         break;
 475                 case Opt_nodatasum:
 476                         btrfs_set_and_info(info, NODATASUM,
 477                                            "setting nodatasum");
 478                         break;
 479                 case Opt_datasum:
 480                         if (btrfs_test_opt(info, NODATASUM)) {
 481                                 if (btrfs_test_opt(info, NODATACOW))
 482                                         btrfs_info(info,
 483                                                    "setting datasum, datacow enabled");
 484                                 else
 485                                         btrfs_info(info, "setting datasum");
 486                         }
 487                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 488                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 489                         break;
 490                 case Opt_nodatacow:
 491                         if (!btrfs_test_opt(info, NODATACOW)) {
 492                                 if (!btrfs_test_opt(info, COMPRESS) ||
 493                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 494                                         btrfs_info(info,
 495                                                    "setting nodatacow, compression disabled");
 496                                 } else {
 497                                         btrfs_info(info, "setting nodatacow");
 498                                 }
 499                         }
 500                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 501                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 502                         btrfs_set_opt(info->mount_opt, NODATACOW);
 503                         btrfs_set_opt(info->mount_opt, NODATASUM);
 504                         break;
 505                 case Opt_datacow:
 506                         btrfs_clear_and_info(info, NODATACOW,
 507                                              "setting datacow");
 508                         break;
 509                 case Opt_compress_force:
 510                 case Opt_compress_force_type:
 511                         compress_force = true;
 512                         /* Fallthrough */
 513                 case Opt_compress:
 514                 case Opt_compress_type:
 515                         saved_compress_type = btrfs_test_opt(info,
 516                                                              COMPRESS) ?
 517                                 info->compress_type : BTRFS_COMPRESS_NONE;
 518                         saved_compress_force =
 519                                 btrfs_test_opt(info, FORCE_COMPRESS);
 520                         if (token == Opt_compress ||
 521                             token == Opt_compress_force ||
 522                             strncmp(args[0].from, "zlib", 4) == 0) {
 523                                 compress_type = "zlib";
 524
 525                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 526                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 527                                 /*
 528                                  * args[0] contains uninitialized data since
 529                                  * for these tokens we don't expect any
 530                                  * parameter.
 531                                  */
 532                                 if (token != Opt_compress &&
 533                                     token != Opt_compress_force)
 534                                         info->compress_level =
 535                                           btrfs_compress_str2level(
 536                                                         BTRFS_COMPRESS_ZLIB,
 537                                                         args[0].from + 4);
 538                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 539                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 540                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 541                                 no_compress = 0;
 542                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 543                                 compress_type = "lzo";
 544                                 info->compress_type = BTRFS_COMPRESS_LZO;
 545                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 546                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 547                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 548                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 549                                 no_compress = 0;
 550                         } else if (strncmp(args[0].from, "zstd", 4) == 0) {
 551                                 compress_type = "zstd";
 552                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 553                                 info->compress_level =
 554                                         btrfs_compress_str2level(
 555                                                          BTRFS_COMPRESS_ZSTD,
 556                                                          args[0].from + 4);
 557                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 558                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 559                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 560                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 561                                 no_compress = 0;
 562                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 563                                 compress_type = "no";
 564                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 565                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 566                                 compress_force = false;
 567                                 no_compress++;
 568                         } else {
 569                                 ret = -EINVAL;
 570                                 goto out;
 571                         }
 572
 573                         if (compress_force) {
 574                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 575                         } else {
 576                                 /*
 577                                  * If we remount from compress-force=xxx to
 578                                  * compress=xxx, we need clear FORCE_COMPRESS
 579                                  * flag, otherwise, there is no way for users
 580                                  * to disable forcible compression separately.
 581                                  */
 582                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 583                         }
 584                         if ((btrfs_test_opt(info, COMPRESS) &&
 585                              (info->compress_type != saved_compress_type ||
 586                               compress_force != saved_compress_force)) ||
 587                             (!btrfs_test_opt(info, COMPRESS) &&
 588                              no_compress == 1)) {
 589                                 btrfs_info(info, "%s %s compression, level %d",
 590                                            (compress_force) ? "force" : "use",
 591                                            compress_type, info->compress_level);
 592                         }
 593                         compress_force = false;
 594                         break;
 595                 case Opt_ssd:
 596                         btrfs_set_and_info(info, SSD,
 597                                            "enabling ssd optimizations");
 598                         btrfs_clear_opt(info->mount_opt, NOSSD);
 599                         break;
 600                 case Opt_ssd_spread:
 601                         btrfs_set_and_info(info, SSD,
 602                                            "enabling ssd optimizations");
 603                         btrfs_set_and_info(info, SSD_SPREAD,
 604                                            "using spread ssd allocation scheme");
 605                         btrfs_clear_opt(info->mount_opt, NOSSD);
 606                         break;
 607                 case Opt_nossd:
 608                         btrfs_set_opt(info->mount_opt, NOSSD);
 609                         btrfs_clear_and_info(info, SSD,
 610                                              "not using ssd optimizations");
 611                         /* Fallthrough */
 612                 case Opt_nossd_spread:
 613                         btrfs_clear_and_info(info, SSD_SPREAD,
 614                                              "not using spread ssd allocation scheme");
 615                         break;
 616                 case Opt_barrier:
 617                         btrfs_clear_and_info(info, NOBARRIER,
 618                                              "turning on barriers");
 619                         break;
 620                 case Opt_nobarrier:
 621                         btrfs_set_and_info(info, NOBARRIER,
 622                                            "turning off barriers");
 623                         break;
 624                 case Opt_thread_pool:
 625                         ret = match_int(&args[0], &intarg);
 626                         if (ret) {
 627                                 goto out;
 628                         } else if (intarg == 0) {
 629                                 ret = -EINVAL;
 630                                 goto out;
 631                         }
 632                         info->thread_pool_size = intarg;
 633                         break;
 634                 case Opt_max_inline:
 635                         num = match_strdup(&args[0]);
 636                         if (num) {
 637                                 info->max_inline = memparse(num, NULL);
 638                                 kfree(num);
 639
 640                                 if (info->max_inline) {
 641                                         info->max_inline = min_t(u64,
 642                                                 info->max_inline,
 643                                                 info->sectorsize);
 644                                 }
 645                                 btrfs_info(info, "max_inline at %llu",
 646                                            info->max_inline);
 647                         } else {
 648                                 ret = -ENOMEM;
 649                                 goto out;
 650                         }
 651                         break;
 652                 case Opt_alloc_start:
 653                         btrfs_info(info,
 654                                 "option alloc_start is obsolete, ignored");
 655                         break;
 656                 case Opt_acl:
 657 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 658                         info->sb->s_flags |= SB_POSIXACL;
 659                         break;
 660 #else
 661                         btrfs_err(info, "support for ACL not compiled in!");
 662                         ret = -EINVAL;
 663                         goto out;
 664 #endif
 665                 case Opt_noacl:
 666                         info->sb->s_flags &= ~SB_POSIXACL;
 667                         break;
 668                 case Opt_notreelog:
 669                         btrfs_set_and_info(info, NOTREELOG,
 670                                            "disabling tree log");
 671                         break;
 672                 case Opt_treelog:
 673                         btrfs_clear_and_info(info, NOTREELOG,
 674                                              "enabling tree log");
 675                         break;
 676                 case Opt_norecovery:
 677                 case Opt_nologreplay:
 678                         btrfs_set_and_info(info, NOLOGREPLAY,
 679                                            "disabling log replay at mount time");
 680                         break;
 681                 case Opt_flushoncommit:
 682                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 683                                            "turning on flush-on-commit");
 684                         break;
 685                 case Opt_noflushoncommit:
 686                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 687                                              "turning off flush-on-commit");
 688                         break;
 689                 case Opt_ratio:
 690                         ret = match_int(&args[0], &intarg);
 691                         if (ret)
 692                                 goto out;
 693                         info->metadata_ratio = intarg;
 694                         btrfs_info(info, "metadata ratio %u",
 695                                    info->metadata_ratio);
 696                         break;
 697                 case Opt_discard:
 698                         btrfs_set_and_info(info, DISCARD,
 699                                            "turning on discard");
 700                         break;
 701                 case Opt_nodiscard:
 702                         btrfs_clear_and_info(info, DISCARD,
 703                                              "turning off discard");
 704                         break;
 705                 case Opt_space_cache:
 706                 case Opt_space_cache_version:
 707                         if (token == Opt_space_cache ||
 708                             strcmp(args[0].from, "v1") == 0) {
 709                                 btrfs_clear_opt(info->mount_opt,
 710                                                 FREE_SPACE_TREE);
 711                                 btrfs_set_and_info(info, SPACE_CACHE,
 712                                            "enabling disk space caching");
 713                         } else if (strcmp(args[0].from, "v2") == 0) {
 714                                 btrfs_clear_opt(info->mount_opt,
 715                                                 SPACE_CACHE);
 716                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 717                                                    "enabling free space tree");
 718                         } else {
 719                                 ret = -EINVAL;
 720                                 goto out;
 721                         }
 722                         break;
 723                 case Opt_rescan_uuid_tree:
 724                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 725                         break;
 726                 case Opt_no_space_cache:
 727                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 728                                 btrfs_clear_and_info(info, SPACE_CACHE,
 729                                              "disabling disk space caching");
 730                         }
 731                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 732                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 733                                              "disabling free space tree");
 734                         }
 735                         break;
 736                 case Opt_inode_cache:
 737                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 738                                            "enabling inode map caching");
 739                         break;
 740                 case Opt_noinode_cache:
 741                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 742                                              "disabling inode map caching");
 743                         break;
 744                 case Opt_clear_cache:
 745                         btrfs_set_and_info(info, CLEAR_CACHE,
 746                                            "force clearing of disk cache");
 747                         break;
 748                 case Opt_user_subvol_rm_allowed:
 749                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 750                         break;
 751                 case Opt_enospc_debug:
 752                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 753                         break;
 754                 case Opt_noenospc_debug:
 755                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 756                         break;
 757                 case Opt_defrag:
 758                         btrfs_set_and_info(info, AUTO_DEFRAG,
 759                                            "enabling auto defrag");
 760                         break;
 761                 case Opt_nodefrag:
 762                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 763                                              "disabling auto defrag");
 764                         break;
 765                 case Opt_recovery:
 766                         btrfs_warn(info,
 767                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 768                         /* fall through */
 769                 case Opt_usebackuproot:
 770                         btrfs_info(info,
 771                                    "trying to use backup root at mount time");
 772                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 773                         break;
 774                 case Opt_skip_balance:
 775                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 776                         break;
 777 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 778                 case Opt_check_integrity_including_extent_data:
 779                         btrfs_info(info,
 780                                    "enabling check integrity including extent data");
 781                         btrfs_set_opt(info->mount_opt,
 782                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 783                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 784                         break;
 785                 case Opt_check_integrity:
 786                         btrfs_info(info, "enabling check integrity");
 787                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 788                         break;
 789                 case Opt_check_integrity_print_mask:
 790                         ret = match_int(&args[0], &intarg);
 791                         if (ret)
 792                                 goto out;
 793                         info->check_integrity_print_mask = intarg;
 794                         btrfs_info(info, "check_integrity_print_mask 0x%x",
 795                                    info->check_integrity_print_mask);
 796                         break;
 797 #else
 798                 case Opt_check_integrity_including_extent_data:
 799                 case Opt_check_integrity:
 800                 case Opt_check_integrity_print_mask:
 801                         btrfs_err(info,
 802                                   "support for check_integrity* not compiled in!");
 803                         ret = -EINVAL;
 804                         goto out;
 805 #endif
 806                 case Opt_fatal_errors:
 807                         if (strcmp(args[0].from, "panic") == 0)
 808                                 btrfs_set_opt(info->mount_opt,
 809                                               PANIC_ON_FATAL_ERROR);
 810                         else if (strcmp(args[0].from, "bug") == 0)
 811                                 btrfs_clear_opt(info->mount_opt,
 812                                               PANIC_ON_FATAL_ERROR);
 813                         else {
 814                                 ret = -EINVAL;
 815                                 goto out;
 816                         }
 817                         break;
 818                 case Opt_commit_interval:
 819                         intarg = 0;
 820                         ret = match_int(&args[0], &intarg);
 821                         if (ret)
 822                                 goto out;
 823                         if (intarg == 0) {
 824                                 btrfs_info(info,
 825                                            "using default commit interval %us",
 826                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 827                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
 828                         } else if (intarg > 300) {
 829                                 btrfs_warn(info, "excessive commit interval %d",
 830                                            intarg);
 831                         }
 832                         info->commit_interval = intarg;
 833                         break;
 834 #ifdef CONFIG_BTRFS_DEBUG
 835                 case Opt_fragment_all:
 836                         btrfs_info(info, "fragmenting all space");
 837                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 838                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 839                         break;
 840                 case Opt_fragment_metadata:
 841                         btrfs_info(info, "fragmenting metadata");
 842                         btrfs_set_opt(info->mount_opt,
 843                                       FRAGMENT_METADATA);
 844                         break;
 845                 case Opt_fragment_data:
 846                         btrfs_info(info, "fragmenting data");
 847                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 848                         break;
 849 #endif
 850 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 851                 case Opt_ref_verify:
 852                         btrfs_info(info, "doing ref verification");
 853                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 854                         break;
 855 #endif
 856                 case Opt_err:
 857                         btrfs_info(info, "unrecognized mount option '%s'", p);
 858                         ret = -EINVAL;
 859                         goto out;
 860                 default:
 861                         break;
 862                 }
 863         }
 864 check:
 865         /*
 866          * Extra check for current option against current flag
 867          */
 868         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & SB_RDONLY)) {
 869                 btrfs_err(info,
 870                           "nologreplay must be used with ro mount option");
 871                 ret = -EINVAL;
 872         }
 873 out:
 874         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 875             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 876             !btrfs_test_opt(info, CLEAR_CACHE)) {
 877                 btrfs_err(info, "cannot disable free space tree");
 878                 ret = -EINVAL;
 879
 880         }
 881         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 882                 btrfs_info(info, "disk space caching is enabled");
 883         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 884                 btrfs_info(info, "using free space tree");
 885         return ret;
 886 }
 887
 888 /*
 889  * Parse mount options that are required early in the mount process.
 890  *
 891  * All other options will be parsed on much later in the mount process and
 892  * only when we need to allocate a new super block.
 893  */
 894 static int btrfs_parse_device_options(const char *options, fmode_t flags,
 895                                       void *holder)
 896 {
 897         substring_t args[MAX_OPT_ARGS];
 898         char *device_name, *opts, *orig, *p;
 899         struct btrfs_device *device = NULL;
 900         int error = 0;
 901
 902         lockdep_assert_held(&uuid_mutex);
 903
 904         if (!options)
 905                 return 0;
 906
 907         /*
 908          * strsep changes the string, duplicate it because btrfs_parse_options
 909          * gets called later
 910          */
 911         opts = kstrdup(options, GFP_KERNEL);
 912         if (!opts)
 913                 return -ENOMEM;
 914         orig = opts;
 915
 916         while ((p = strsep(&opts, ",")) != NULL) {
 917                 int token;
 918
 919                 if (!*p)
 920                         continue;
 921
 922                 token = match_token(p, tokens, args);
 923                 if (token == Opt_device) {
 924                         device_name = match_strdup(&args[0]);
 925                         if (!device_name) {
 926                                 error = -ENOMEM;
 927                                 goto out;
 928                         }
 929                         device = btrfs_scan_one_device(device_name, flags,
 930                                         holder);
 931                         kfree(device_name);
 932                         if (IS_ERR(device)) {
 933                                 error = PTR_ERR(device);
 934                                 goto out;
 935                         }
 936                 }
 937         }
 938
 939 out:
 940         kfree(orig);
 941         return error;
 942 }
 943
 944 /*
 945  * Parse mount options that are related to subvolume id
 946  *
 947  * The value is later passed to mount_subvol()
 948  */
 949 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
 950                 u64 *subvol_objectid)
 951 {
 952         substring_t args[MAX_OPT_ARGS];
 953         char *opts, *orig, *p;
 954         int error = 0;
 955         u64 subvolid;
 956
 957         if (!options)
 958                 return 0;
 959
 960         /*
 961          * strsep changes the string, duplicate it because
 962          * btrfs_parse_device_options gets called later
 963          */
 964         opts = kstrdup(options, GFP_KERNEL);
 965         if (!opts)
 966                 return -ENOMEM;
 967         orig = opts;
 968
 969         while ((p = strsep(&opts, ",")) != NULL) {
 970                 int token;
 971                 if (!*p)
 972                         continue;
 973
 974                 token = match_token(p, tokens, args);
 975                 switch (token) {
 976                 case Opt_subvol:
 977                         kfree(*subvol_name);
 978                         *subvol_name = match_strdup(&args[0]);
 979                         if (!*subvol_name) {
 980                                 error = -ENOMEM;
 981                                 goto out;
 982                         }
 983                         break;
 984                 case Opt_subvolid:
 985                         error = match_u64(&args[0], &subvolid);
 986                         if (error)
 987                                 goto out;
 988
 989                         /* we want the original fs_tree */
 990                         if (subvolid == 0)
 991                                 subvolid = BTRFS_FS_TREE_OBJECTID;
 992
 993                         *subvol_objectid = subvolid;
 994                         break;
 995                 case Opt_subvolrootid:
 996                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
 997                         break;
 998                 default:
 999                         break;
1000                 }
1001         }
1002
1003 out:
1004         kfree(orig);
1005         return error;
1006 }
1007
1008 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
1009                                            u64 subvol_objectid)
1010 {
1011         struct btrfs_root *root = fs_info->tree_root;
1012         struct btrfs_root *fs_root;
1013         struct btrfs_root_ref *root_ref;
1014         struct btrfs_inode_ref *inode_ref;
1015         struct btrfs_key key;
1016         struct btrfs_path *path = NULL;
1017         char *name = NULL, *ptr;
1018         u64 dirid;
1019         int len;
1020         int ret;
1021
1022         path = btrfs_alloc_path();
1023         if (!path) {
1024                 ret = -ENOMEM;
1025                 goto err;
1026         }
1027         path->leave_spinning = 1;
1028
1029         name = kmalloc(PATH_MAX, GFP_KERNEL);
1030         if (!name) {
1031                 ret = -ENOMEM;
1032                 goto err;
1033         }
1034         ptr = name + PATH_MAX - 1;
1035         ptr[0] = '\0';
1036
1037         /*
1038          * Walk up the subvolume trees in the tree of tree roots by root
1039          * backrefs until we hit the top-level subvolume.
1040          */
1041         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1042                 key.objectid = subvol_objectid;
1043                 key.type = BTRFS_ROOT_BACKREF_KEY;
1044                 key.offset = (u64)-1;
1045
1046                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1047                 if (ret < 0) {
1048                         goto err;
1049                 } else if (ret > 0) {
1050                         ret = btrfs_previous_item(root, path, subvol_objectid,
1051                                                   BTRFS_ROOT_BACKREF_KEY);
1052                         if (ret < 0) {
1053                                 goto err;
1054                         } else if (ret > 0) {
1055                                 ret = -ENOENT;
1056                                 goto err;
1057                         }
1058                 }
1059
1060                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1061                 subvol_objectid = key.offset;
1062
1063                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1064                                           struct btrfs_root_ref);
1065                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1066                 ptr -= len + 1;
1067                 if (ptr < name) {
1068                         ret = -ENAMETOOLONG;
1069                         goto err;
1070                 }
1071                 read_extent_buffer(path->nodes[0], ptr + 1,
1072                                    (unsigned long)(root_ref + 1), len);
1073                 ptr[0] = '/';
1074                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1075                 btrfs_release_path(path);
1076
1077                 key.objectid = subvol_objectid;
1078                 key.type = BTRFS_ROOT_ITEM_KEY;
1079                 key.offset = (u64)-1;
1080                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1081                 if (IS_ERR(fs_root)) {
1082                         ret = PTR_ERR(fs_root);
1083                         goto err;
1084                 }
1085
1086                 /*
1087                  * Walk up the filesystem tree by inode refs until we hit the
1088                  * root directory.
1089                  */
1090                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1091                         key.objectid = dirid;
1092                         key.type = BTRFS_INODE_REF_KEY;
1093                         key.offset = (u64)-1;
1094
1095                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1096                         if (ret < 0) {
1097                                 goto err;
1098                         } else if (ret > 0) {
1099                                 ret = btrfs_previous_item(fs_root, path, dirid,
1100                                                           BTRFS_INODE_REF_KEY);
1101                                 if (ret < 0) {
1102                                         goto err;
1103                                 } else if (ret > 0) {
1104                                         ret = -ENOENT;
1105                                         goto err;
1106                                 }
1107                         }
1108
1109                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1110                         dirid = key.offset;
1111
1112                         inode_ref = btrfs_item_ptr(path->nodes[0],
1113                                                    path->slots[0],
1114                                                    struct btrfs_inode_ref);
1115                         len = btrfs_inode_ref_name_len(path->nodes[0],
1116                                                        inode_ref);
1117                         ptr -= len + 1;
1118                         if (ptr < name) {
1119                                 ret = -ENAMETOOLONG;
1120                                 goto err;
1121                         }
1122                         read_extent_buffer(path->nodes[0], ptr + 1,
1123                                            (unsigned long)(inode_ref + 1), len);
1124                         ptr[0] = '/';
1125                         btrfs_release_path(path);
1126                 }
1127         }
1128
1129         btrfs_free_path(path);
1130         if (ptr == name + PATH_MAX - 1) {
1131                 name[0] = '/';
1132                 name[1] = '\0';
1133         } else {
1134                 memmove(name, ptr, name + PATH_MAX - ptr);
1135         }
1136         return name;
1137
1138 err:
1139         btrfs_free_path(path);
1140         kfree(name);
1141         return ERR_PTR(ret);
1142 }
1143
1144 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1145 {
1146         struct btrfs_root *root = fs_info->tree_root;
1147         struct btrfs_dir_item *di;
1148         struct btrfs_path *path;
1149         struct btrfs_key location;
1150         u64 dir_id;
1151
1152         path = btrfs_alloc_path();
1153         if (!path)
1154                 return -ENOMEM;
1155         path->leave_spinning = 1;
1156
1157         /*
1158          * Find the "default" dir item which points to the root item that we
1159          * will mount by default if we haven't been given a specific subvolume
1160          * to mount.
1161          */
1162         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1163         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1164         if (IS_ERR(di)) {
1165                 btrfs_free_path(path);
1166                 return PTR_ERR(di);
1167         }
1168         if (!di) {
1169                 /*
1170                  * Ok the default dir item isn't there.  This is weird since
1171                  * it's always been there, but don't freak out, just try and
1172                  * mount the top-level subvolume.
1173                  */
1174                 btrfs_free_path(path);
1175                 *objectid = BTRFS_FS_TREE_OBJECTID;
1176                 return 0;
1177         }
1178
1179         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1180         btrfs_free_path(path);
1181         *objectid = location.objectid;
1182         return 0;
1183 }
1184
1185 static int btrfs_fill_super(struct super_block *sb,
1186                             struct btrfs_fs_devices *fs_devices,
1187                             void *data)
1188 {
1189         struct inode *inode;
1190         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1191         struct btrfs_key key;
1192         int err;
1193
1194         sb->s_maxbytes = MAX_LFS_FILESIZE;
1195         sb->s_magic = BTRFS_SUPER_MAGIC;
1196         sb->s_op = &btrfs_super_ops;
1197         sb->s_d_op = &btrfs_dentry_operations;
1198         sb->s_export_op = &btrfs_export_ops;
1199         sb->s_xattr = btrfs_xattr_handlers;
1200         sb->s_time_gran = 1;
1201 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1202         sb->s_flags |= SB_POSIXACL;
1203 #endif
1204         sb->s_flags |= SB_I_VERSION;
1205         sb->s_iflags |= SB_I_CGROUPWB;
1206
1207         err = super_setup_bdi(sb);
1208         if (err) {
1209                 btrfs_err(fs_info, "super_setup_bdi failed");
1210                 return err;
1211         }
1212
1213         err = open_ctree(sb, fs_devices, (char *)data);
1214         if (err) {
1215                 btrfs_err(fs_info, "open_ctree failed");
1216                 return err;
1217         }
1218
1219         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1220         key.type = BTRFS_INODE_ITEM_KEY;
1221         key.offset = 0;
1222         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1223         if (IS_ERR(inode)) {
1224                 err = PTR_ERR(inode);
1225                 goto fail_close;
1226         }
1227
1228         sb->s_root = d_make_root(inode);
1229         if (!sb->s_root) {
1230                 err = -ENOMEM;
1231                 goto fail_close;
1232         }
1233
1234         cleancache_init_fs(sb);
1235         sb->s_flags |= SB_ACTIVE;
1236         return 0;
1237
1238 fail_close:
1239         close_ctree(fs_info);
1240         return err;
1241 }
1242
1243 int btrfs_sync_fs(struct super_block *sb, int wait)
1244 {
1245         struct btrfs_trans_handle *trans;
1246         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1247         struct btrfs_root *root = fs_info->tree_root;
1248
1249         trace_btrfs_sync_fs(fs_info, wait);
1250
1251         if (!wait) {
1252                 filemap_flush(fs_info->btree_inode->i_mapping);
1253                 return 0;
1254         }
1255
1256         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1257
1258         trans = btrfs_attach_transaction_barrier(root);
1259         if (IS_ERR(trans)) {
1260                 /* no transaction, don't bother */
1261                 if (PTR_ERR(trans) == -ENOENT) {
1262                         /*
1263                          * Exit unless we have some pending changes
1264                          * that need to go through commit
1265                          */
1266                         if (fs_info->pending_changes == 0)
1267                                 return 0;
1268                         /*
1269                          * A non-blocking test if the fs is frozen. We must not
1270                          * start a new transaction here otherwise a deadlock
1271                          * happens. The pending operations are delayed to the
1272                          * next commit after thawing.
1273                          */
1274                         if (sb_start_write_trylock(sb))
1275                                 sb_end_write(sb);
1276                         else
1277                                 return 0;
1278                         trans = btrfs_start_transaction(root, 0);
1279                 }
1280                 if (IS_ERR(trans))
1281                         return PTR_ERR(trans);
1282         }
1283         return btrfs_commit_transaction(trans);
1284 }
1285
1286 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1287 {
1288         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1289         const char *compress_type;
1290
1291         if (btrfs_test_opt(info, DEGRADED))
1292                 seq_puts(seq, ",degraded");
1293         if (btrfs_test_opt(info, NODATASUM))
1294                 seq_puts(seq, ",nodatasum");
1295         if (btrfs_test_opt(info, NODATACOW))
1296                 seq_puts(seq, ",nodatacow");
1297         if (btrfs_test_opt(info, NOBARRIER))
1298                 seq_puts(seq, ",nobarrier");
1299         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1300                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1301         if (info->thread_pool_size !=  min_t(unsigned long,
1302                                              num_online_cpus() + 2, 8))
1303                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1304         if (btrfs_test_opt(info, COMPRESS)) {
1305                 compress_type = btrfs_compress_type2str(info->compress_type);
1306                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1307                         seq_printf(seq, ",compress-force=%s", compress_type);
1308                 else
1309                         seq_printf(seq, ",compress=%s", compress_type);
1310                 if (info->compress_level)
1311                         seq_printf(seq, ":%d", info->compress_level);
1312         }
1313         if (btrfs_test_opt(info, NOSSD))
1314                 seq_puts(seq, ",nossd");
1315         if (btrfs_test_opt(info, SSD_SPREAD))
1316                 seq_puts(seq, ",ssd_spread");
1317         else if (btrfs_test_opt(info, SSD))
1318                 seq_puts(seq, ",ssd");
1319         if (btrfs_test_opt(info, NOTREELOG))
1320                 seq_puts(seq, ",notreelog");
1321         if (btrfs_test_opt(info, NOLOGREPLAY))
1322                 seq_puts(seq, ",nologreplay");
1323         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1324                 seq_puts(seq, ",flushoncommit");
1325         if (btrfs_test_opt(info, DISCARD))
1326                 seq_puts(seq, ",discard");
1327         if (!(info->sb->s_flags & SB_POSIXACL))
1328                 seq_puts(seq, ",noacl");
1329         if (btrfs_test_opt(info, SPACE_CACHE))
1330                 seq_puts(seq, ",space_cache");
1331         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1332                 seq_puts(seq, ",space_cache=v2");
1333         else
1334                 seq_puts(seq, ",nospace_cache");
1335         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1336                 seq_puts(seq, ",rescan_uuid_tree");
1337         if (btrfs_test_opt(info, CLEAR_CACHE))
1338                 seq_puts(seq, ",clear_cache");
1339         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1340                 seq_puts(seq, ",user_subvol_rm_allowed");
1341         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1342                 seq_puts(seq, ",enospc_debug");
1343         if (btrfs_test_opt(info, AUTO_DEFRAG))
1344                 seq_puts(seq, ",autodefrag");
1345         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1346                 seq_puts(seq, ",inode_cache");
1347         if (btrfs_test_opt(info, SKIP_BALANCE))
1348                 seq_puts(seq, ",skip_balance");
1349 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1350         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1351                 seq_puts(seq, ",check_int_data");
1352         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1353                 seq_puts(seq, ",check_int");
1354         if (info->check_integrity_print_mask)
1355                 seq_printf(seq, ",check_int_print_mask=%d",
1356                                 info->check_integrity_print_mask);
1357 #endif
1358         if (info->metadata_ratio)
1359                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1360         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1361                 seq_puts(seq, ",fatal_errors=panic");
1362         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1363                 seq_printf(seq, ",commit=%u", info->commit_interval);
1364 #ifdef CONFIG_BTRFS_DEBUG
1365         if (btrfs_test_opt(info, FRAGMENT_DATA))
1366                 seq_puts(seq, ",fragment=data");
1367         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1368                 seq_puts(seq, ",fragment=metadata");
1369 #endif
1370         if (btrfs_test_opt(info, REF_VERIFY))
1371                 seq_puts(seq, ",ref_verify");
1372         seq_printf(seq, ",subvolid=%llu",
1373                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1374         seq_puts(seq, ",subvol=");
1375         seq_dentry(seq, dentry, " \t\n\\");
1376         return 0;
1377 }
1378
1379 static int btrfs_test_super(struct super_block *s, void *data)
1380 {
1381         struct btrfs_fs_info *p = data;
1382         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1383
1384         return fs_info->fs_devices == p->fs_devices;
1385 }
1386
1387 static int btrfs_set_super(struct super_block *s, void *data)
1388 {
1389         int err = set_anon_super(s, data);
1390         if (!err)
1391                 s->s_fs_info = data;
1392         return err;
1393 }
1394
1395 /*
1396  * subvolumes are identified by ino 256
1397  */
1398 static inline int is_subvolume_inode(struct inode *inode)
1399 {
1400         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1401                 return 1;
1402         return 0;
1403 }
1404
1405 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1406                                    struct vfsmount *mnt)
1407 {
1408         struct dentry *root;
1409         int ret;
1410
1411         if (!subvol_name) {
1412                 if (!subvol_objectid) {
1413                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1414                                                           &subvol_objectid);
1415                         if (ret) {
1416                                 root = ERR_PTR(ret);
1417                                 goto out;
1418                         }
1419                 }
1420                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1421                                                             subvol_objectid);
1422                 if (IS_ERR(subvol_name)) {
1423                         root = ERR_CAST(subvol_name);
1424                         subvol_name = NULL;
1425                         goto out;
1426                 }
1427
1428         }
1429
1430         root = mount_subtree(mnt, subvol_name);
1431         /* mount_subtree() drops our reference on the vfsmount. */
1432         mnt = NULL;
1433
1434         if (!IS_ERR(root)) {
1435                 struct super_block *s = root->d_sb;
1436                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1437                 struct inode *root_inode = d_inode(root);
1438                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1439
1440                 ret = 0;
1441                 if (!is_subvolume_inode(root_inode)) {
1442                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1443                                subvol_name);
1444                         ret = -EINVAL;
1445                 }
1446                 if (subvol_objectid && root_objectid != subvol_objectid) {
1447                         /*
1448                          * This will also catch a race condition where a
1449                          * subvolume which was passed by ID is renamed and
1450                          * another subvolume is renamed over the old location.
1451                          */
1452                         btrfs_err(fs_info,
1453                                   "subvol '%s' does not match subvolid %llu",
1454                                   subvol_name, subvol_objectid);
1455                         ret = -EINVAL;
1456                 }
1457                 if (ret) {
1458                         dput(root);
1459                         root = ERR_PTR(ret);
1460                         deactivate_locked_super(s);
1461                 }
1462         }
1463
1464 out:
1465         mntput(mnt);
1466         kfree(subvol_name);
1467         return root;
1468 }
1469
1470 /*
1471  * Find a superblock for the given device / mount point.
1472  *
1473  * Note: This is based on mount_bdev from fs/super.c with a few additions
1474  *       for multiple device setup.  Make sure to keep it in sync.
1475  */
1476 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1477                 int flags, const char *device_name, void *data)
1478 {
1479         struct block_device *bdev = NULL;
1480         struct super_block *s;
1481         struct btrfs_device *device = NULL;
1482         struct btrfs_fs_devices *fs_devices = NULL;
1483         struct btrfs_fs_info *fs_info = NULL;
1484         void *new_sec_opts = NULL;
1485         fmode_t mode = FMODE_READ;
1486         int error = 0;
1487
1488         if (!(flags & SB_RDONLY))
1489                 mode |= FMODE_WRITE;
1490
1491         if (data) {
1492                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1493                 if (error)
1494                         return ERR_PTR(error);
1495         }
1496
1497         /*
1498          * Setup a dummy root and fs_info for test/set super.  This is because
1499          * we don't actually fill this stuff out until open_ctree, but we need
1500          * it for searching for existing supers, so this lets us do that and
1501          * then open_ctree will properly initialize everything later.
1502          */
1503         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1504         if (!fs_info) {
1505                 error = -ENOMEM;
1506                 goto error_sec_opts;
1507         }
1508
1509         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1510         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1511         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1512                 error = -ENOMEM;
1513                 goto error_fs_info;
1514         }
1515
1516         mutex_lock(&uuid_mutex);
1517         error = btrfs_parse_device_options(data, mode, fs_type);
1518         if (error) {
1519                 mutex_unlock(&uuid_mutex);
1520                 goto error_fs_info;
1521         }
1522
1523         device = btrfs_scan_one_device(device_name, mode, fs_type);
1524         if (IS_ERR(device)) {
1525                 mutex_unlock(&uuid_mutex);
1526                 error = PTR_ERR(device);
1527                 goto error_fs_info;
1528         }
1529
1530         fs_devices = device->fs_devices;
1531         fs_info->fs_devices = fs_devices;
1532
1533         error = btrfs_open_devices(fs_devices, mode, fs_type);
1534         mutex_unlock(&uuid_mutex);
1535         if (error)
1536                 goto error_fs_info;
1537
1538         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1539                 error = -EACCES;
1540                 goto error_close_devices;
1541         }
1542
1543         bdev = fs_devices->latest_bdev;
1544         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1545                  fs_info);
1546         if (IS_ERR(s)) {
1547                 error = PTR_ERR(s);
1548                 goto error_close_devices;
1549         }
1550
1551         if (s->s_root) {
1552                 btrfs_close_devices(fs_devices);
1553                 free_fs_info(fs_info);
1554                 if ((flags ^ s->s_flags) & SB_RDONLY)
1555                         error = -EBUSY;
1556         } else {
1557                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1558                 btrfs_sb(s)->bdev_holder = fs_type;
1559                 if (!strstr(crc32c_impl(), "generic"))
1560                         set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
1561                 error = btrfs_fill_super(s, fs_devices, data);
1562         }
1563         if (!error)
1564                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1565         security_free_mnt_opts(&new_sec_opts);
1566         if (error) {
1567                 deactivate_locked_super(s);
1568                 return ERR_PTR(error);
1569         }
1570
1571         return dget(s->s_root);
1572
1573 error_close_devices:
1574         btrfs_close_devices(fs_devices);
1575 error_fs_info:
1576         free_fs_info(fs_info);
1577 error_sec_opts:
1578         security_free_mnt_opts(&new_sec_opts);
1579         return ERR_PTR(error);
1580 }
1581
1582 /*
1583  * Mount function which is called by VFS layer.
1584  *
1585  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1586  * which needs vfsmount* of device's root (/).  This means device's root has to
1587  * be mounted internally in any case.
1588  *
1589  * Operation flow:
1590  *   1. Parse subvol id related options for later use in mount_subvol().
1591  *
1592  *   2. Mount device's root (/) by calling vfs_kern_mount().
1593  *
1594  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1595  *      first place. In order to avoid calling btrfs_mount() again, we use
1596  *      different file_system_type which is not registered to VFS by
1597  *      register_filesystem() (btrfs_root_fs_type). As a result,
1598  *      btrfs_mount_root() is called. The return value will be used by
1599  *      mount_subtree() in mount_subvol().
1600  *
1601  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1602  *      "btrfs subvolume set-default", mount_subvol() is called always.
1603  */
1604 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1605                 const char *device_name, void *data)
1606 {
1607         struct vfsmount *mnt_root;
1608         struct dentry *root;
1609         char *subvol_name = NULL;
1610         u64 subvol_objectid = 0;
1611         int error = 0;
1612
1613         error = btrfs_parse_subvol_options(data, &subvol_name,
1614                                         &subvol_objectid);
1615         if (error) {
1616                 kfree(subvol_name);
1617                 return ERR_PTR(error);
1618         }
1619
1620         /* mount device's root (/) */
1621         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1622         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1623                 if (flags & SB_RDONLY) {
1624                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1625                                 flags & ~SB_RDONLY, device_name, data);
1626                 } else {
1627                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1628                                 flags | SB_RDONLY, device_name, data);
1629                         if (IS_ERR(mnt_root)) {
1630                                 root = ERR_CAST(mnt_root);
1631                                 kfree(subvol_name);
1632                                 goto out;
1633                         }
1634
1635                         down_write(&mnt_root->mnt_sb->s_umount);
1636                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1637                         up_write(&mnt_root->mnt_sb->s_umount);
1638                         if (error < 0) {
1639                                 root = ERR_PTR(error);
1640                                 mntput(mnt_root);
1641                                 kfree(subvol_name);
1642                                 goto out;
1643                         }
1644                 }
1645         }
1646         if (IS_ERR(mnt_root)) {
1647                 root = ERR_CAST(mnt_root);
1648                 kfree(subvol_name);
1649                 goto out;
1650         }
1651
1652         /* mount_subvol() will free subvol_name and mnt_root */
1653         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1654
1655 out:
1656         return root;
1657 }
1658
1659 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1660                                      u32 new_pool_size, u32 old_pool_size)
1661 {
1662         if (new_pool_size == old_pool_size)
1663                 return;
1664
1665         fs_info->thread_pool_size = new_pool_size;
1666
1667         btrfs_info(fs_info, "resize thread pool %d -> %d",
1668                old_pool_size, new_pool_size);
1669
1670         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1671         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1672         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1673         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1674         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1675         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1676         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1677                                 new_pool_size);
1678         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1679         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1680         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1681         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1682         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1683                                 new_pool_size);
1684 }
1685
1686 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1687 {
1688         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1689 }
1690
1691 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1692                                        unsigned long old_opts, int flags)
1693 {
1694         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1695             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1696              (flags & SB_RDONLY))) {
1697                 /* wait for any defraggers to finish */
1698                 wait_event(fs_info->transaction_wait,
1699                            (atomic_read(&fs_info->defrag_running) == 0));
1700                 if (flags & SB_RDONLY)
1701                         sync_filesystem(fs_info->sb);
1702         }
1703 }
1704
1705 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1706                                          unsigned long old_opts)
1707 {
1708         /*
1709          * We need to cleanup all defragable inodes if the autodefragment is
1710          * close or the filesystem is read only.
1711          */
1712         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1713             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1714                 btrfs_cleanup_defrag_inodes(fs_info);
1715         }
1716
1717         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1718 }
1719
1720 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1721 {
1722         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1723         struct btrfs_root *root = fs_info->tree_root;
1724         unsigned old_flags = sb->s_flags;
1725         unsigned long old_opts = fs_info->mount_opt;
1726         unsigned long old_compress_type = fs_info->compress_type;
1727         u64 old_max_inline = fs_info->max_inline;
1728         u32 old_thread_pool_size = fs_info->thread_pool_size;
1729         u32 old_metadata_ratio = fs_info->metadata_ratio;
1730         int ret;
1731
1732         sync_filesystem(sb);
1733         btrfs_remount_prepare(fs_info);
1734
1735         if (data) {
1736                 void *new_sec_opts = NULL;
1737
1738                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1739                 if (!ret)
1740                         ret = security_sb_remount(sb, new_sec_opts);
1741                 security_free_mnt_opts(&new_sec_opts);
1742                 if (ret)
1743                         goto restore;
1744         }
1745
1746         ret = btrfs_parse_options(fs_info, data, *flags);
1747         if (ret)
1748                 goto restore;
1749
1750         btrfs_remount_begin(fs_info, old_opts, *flags);
1751         btrfs_resize_thread_pool(fs_info,
1752                 fs_info->thread_pool_size, old_thread_pool_size);
1753
1754         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1755                 goto out;
1756
1757         if (*flags & SB_RDONLY) {
1758                 /*
1759                  * this also happens on 'umount -rf' or on shutdown, when
1760                  * the filesystem is busy.
1761                  */
1762                 cancel_work_sync(&fs_info->async_reclaim_work);
1763
1764                 /* wait for the uuid_scan task to finish */
1765                 down(&fs_info->uuid_tree_rescan_sem);
1766                 /* avoid complains from lockdep et al. */
1767                 up(&fs_info->uuid_tree_rescan_sem);
1768
1769                 sb->s_flags |= SB_RDONLY;
1770
1771                 /*
1772                  * Setting SB_RDONLY will put the cleaner thread to
1773                  * sleep at the next loop if it's already active.
1774                  * If it's already asleep, we'll leave unused block
1775                  * groups on disk until we're mounted read-write again
1776                  * unless we clean them up here.
1777                  */
1778                 btrfs_delete_unused_bgs(fs_info);
1779
1780                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1781                 btrfs_scrub_cancel(fs_info);
1782                 btrfs_pause_balance(fs_info);
1783
1784                 ret = btrfs_commit_super(fs_info);
1785                 if (ret)
1786                         goto restore;
1787         } else {
1788                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1789                         btrfs_err(fs_info,
1790                                 "Remounting read-write after error is not allowed");
1791                         ret = -EINVAL;
1792                         goto restore;
1793                 }
1794                 if (fs_info->fs_devices->rw_devices == 0) {
1795                         ret = -EACCES;
1796                         goto restore;
1797                 }
1798
1799                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1800                         btrfs_warn(fs_info,
1801                 "too many missing devices, writable remount is not allowed");
1802                         ret = -EACCES;
1803                         goto restore;
1804                 }
1805
1806                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1807                         ret = -EINVAL;
1808                         goto restore;
1809                 }
1810
1811                 ret = btrfs_cleanup_fs_roots(fs_info);
1812                 if (ret)
1813                         goto restore;
1814
1815                 /* recover relocation */
1816                 mutex_lock(&fs_info->cleaner_mutex);
1817                 ret = btrfs_recover_relocation(root);
1818                 mutex_unlock(&fs_info->cleaner_mutex);
1819                 if (ret)
1820                         goto restore;
1821
1822                 ret = btrfs_resume_balance_async(fs_info);
1823                 if (ret)
1824                         goto restore;
1825
1826                 ret = btrfs_resume_dev_replace_async(fs_info);
1827                 if (ret) {
1828                         btrfs_warn(fs_info, "failed to resume dev_replace");
1829                         goto restore;
1830                 }
1831
1832                 btrfs_qgroup_rescan_resume(fs_info);
1833
1834                 if (!fs_info->uuid_root) {
1835                         btrfs_info(fs_info, "creating UUID tree");
1836                         ret = btrfs_create_uuid_tree(fs_info);
1837                         if (ret) {
1838                                 btrfs_warn(fs_info,
1839                                            "failed to create the UUID tree %d",
1840                                            ret);
1841                                 goto restore;
1842                         }
1843                 }
1844                 sb->s_flags &= ~SB_RDONLY;
1845
1846                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1847         }
1848 out:
1849         wake_up_process(fs_info->transaction_kthread);
1850         btrfs_remount_cleanup(fs_info, old_opts);
1851         return 0;
1852
1853 restore:
1854         /* We've hit an error - don't reset SB_RDONLY */
1855         if (sb_rdonly(sb))
1856                 old_flags |= SB_RDONLY;
1857         sb->s_flags = old_flags;
1858         fs_info->mount_opt = old_opts;
1859         fs_info->compress_type = old_compress_type;
1860         fs_info->max_inline = old_max_inline;
1861         btrfs_resize_thread_pool(fs_info,
1862                 old_thread_pool_size, fs_info->thread_pool_size);
1863         fs_info->metadata_ratio = old_metadata_ratio;
1864         btrfs_remount_cleanup(fs_info, old_opts);
1865         return ret;
1866 }
1867
1868 /* Used to sort the devices by max_avail(descending sort) */
1869 static inline int btrfs_cmp_device_free_bytes(const void *dev_info1,
1870                                        const void *dev_info2)
1871 {
1872         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1873             ((struct btrfs_device_info *)dev_info2)->max_avail)
1874                 return -1;
1875         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1876                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1877                 return 1;
1878         else
1879         return 0;
1880 }
1881
1882 /*
1883  * sort the devices by max_avail, in which max free extent size of each device
1884  * is stored.(Descending Sort)
1885  */
1886 static inline void btrfs_descending_sort_devices(
1887                                         struct btrfs_device_info *devices,
1888                                         size_t nr_devices)
1889 {
1890         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1891              btrfs_cmp_device_free_bytes, NULL);
1892 }
1893
1894 /*
1895  * The helper to calc the free space on the devices that can be used to store
1896  * file data.
1897  */
1898 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1899                                               u64 *free_bytes)
1900 {
1901         struct btrfs_device_info *devices_info;
1902         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1903         struct btrfs_device *device;
1904         u64 type;
1905         u64 avail_space;
1906         u64 min_stripe_size;
1907         int num_stripes = 1;
1908         int i = 0, nr_devices;
1909         const struct btrfs_raid_attr *rattr;
1910
1911         /*
1912          * We aren't under the device list lock, so this is racy-ish, but good
1913          * enough for our purposes.
1914          */
1915         nr_devices = fs_info->fs_devices->open_devices;
1916         if (!nr_devices) {
1917                 smp_mb();
1918                 nr_devices = fs_info->fs_devices->open_devices;
1919                 ASSERT(nr_devices);
1920                 if (!nr_devices) {
1921                         *free_bytes = 0;
1922                         return 0;
1923                 }
1924         }
1925
1926         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1927                                GFP_KERNEL);
1928         if (!devices_info)
1929                 return -ENOMEM;
1930
1931         /* calc min stripe number for data space allocation */
1932         type = btrfs_data_alloc_profile(fs_info);
1933         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1934
1935         if (type & BTRFS_BLOCK_GROUP_RAID0)
1936                 num_stripes = nr_devices;
1937         else if (type & BTRFS_BLOCK_GROUP_RAID1)
1938                 num_stripes = 2;
1939         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1940                 num_stripes = 4;
1941
1942         /* Adjust for more than 1 stripe per device */
1943         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1944
1945         rcu_read_lock();
1946         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1947                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1948                                                 &device->dev_state) ||
1949                     !device->bdev ||
1950                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1951                         continue;
1952
1953                 if (i >= nr_devices)
1954                         break;
1955
1956                 avail_space = device->total_bytes - device->bytes_used;
1957
1958                 /* align with stripe_len */
1959                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1960
1961                 /*
1962                  * In order to avoid overwriting the superblock on the drive,
1963                  * btrfs starts at an offset of at least 1MB when doing chunk
1964                  * allocation.
1965                  *
1966                  * This ensures we have at least min_stripe_size free space
1967                  * after excluding 1MB.
1968                  */
1969                 if (avail_space <= SZ_1M + min_stripe_size)
1970                         continue;
1971
1972                 avail_space -= SZ_1M;
1973
1974                 devices_info[i].dev = device;
1975                 devices_info[i].max_avail = avail_space;
1976
1977                 i++;
1978         }
1979         rcu_read_unlock();
1980
1981         nr_devices = i;
1982
1983         btrfs_descending_sort_devices(devices_info, nr_devices);
1984
1985         i = nr_devices - 1;
1986         avail_space = 0;
1987         while (nr_devices >= rattr->devs_min) {
1988                 num_stripes = min(num_stripes, nr_devices);
1989
1990                 if (devices_info[i].max_avail >= min_stripe_size) {
1991                         int j;
1992                         u64 alloc_size;
1993
1994                         avail_space += devices_info[i].max_avail * num_stripes;
1995                         alloc_size = devices_info[i].max_avail;
1996                         for (j = i + 1 - num_stripes; j <= i; j++)
1997                                 devices_info[j].max_avail -= alloc_size;
1998                 }
1999                 i--;
2000                 nr_devices--;
2001         }
2002
2003         kfree(devices_info);
2004         *free_bytes = avail_space;
2005         return 0;
2006 }
2007
2008 /*
2009  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2010  *
2011  * If there's a redundant raid level at DATA block groups, use the respective
2012  * multiplier to scale the sizes.
2013  *
2014  * Unused device space usage is based on simulating the chunk allocator
2015  * algorithm that respects the device sizes and order of allocations.  This is
2016  * a close approximation of the actual use but there are other factors that may
2017  * change the result (like a new metadata chunk).
2018  *
2019  * If metadata is exhausted, f_bavail will be 0.
2020  */
2021 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2022 {
2023         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2024         struct btrfs_super_block *disk_super = fs_info->super_copy;
2025         struct list_head *head = &fs_info->space_info;
2026         struct btrfs_space_info *found;
2027         u64 total_used = 0;
2028         u64 total_free_data = 0;
2029         u64 total_free_meta = 0;
2030         int bits = dentry->d_sb->s_blocksize_bits;
2031         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2032         unsigned factor = 1;
2033         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2034         int ret;
2035         u64 thresh = 0;
2036         int mixed = 0;
2037
2038         rcu_read_lock();
2039         list_for_each_entry_rcu(found, head, list) {
2040                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2041                         int i;
2042
2043                         total_free_data += found->disk_total - found->disk_used;
2044                         total_free_data -=
2045                                 btrfs_account_ro_block_groups_free_space(found);
2046
2047                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2048                                 if (!list_empty(&found->block_groups[i]))
2049                                         factor = btrfs_bg_type_to_factor(
2050                                                 btrfs_raid_array[i].bg_flag);
2051                         }
2052                 }
2053
2054                 /*
2055                  * Metadata in mixed block goup profiles are accounted in data
2056                  */
2057                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2058                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2059                                 mixed = 1;
2060                         else
2061                                 total_free_meta += found->disk_total -
2062                                         found->disk_used;
2063                 }
2064
2065                 total_used += found->disk_used;
2066         }
2067
2068         rcu_read_unlock();
2069
2070         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2071         buf->f_blocks >>= bits;
2072         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2073
2074         /* Account global block reserve as used, it's in logical size already */
2075         spin_lock(&block_rsv->lock);
2076         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2077         if (buf->f_bfree >= block_rsv->size >> bits)
2078                 buf->f_bfree -= block_rsv->size >> bits;
2079         else
2080                 buf->f_bfree = 0;
2081         spin_unlock(&block_rsv->lock);
2082
2083         buf->f_bavail = div_u64(total_free_data, factor);
2084         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2085         if (ret)
2086                 return ret;
2087         buf->f_bavail += div_u64(total_free_data, factor);
2088         buf->f_bavail = buf->f_bavail >> bits;
2089
2090         /*
2091          * We calculate the remaining metadata space minus global reserve. If
2092          * this is (supposedly) smaller than zero, there's no space. But this
2093          * does not hold in practice, the exhausted state happens where's still
2094          * some positive delta. So we apply some guesswork and compare the
2095          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2096          *
2097          * We probably cannot calculate the exact threshold value because this
2098          * depends on the internal reservations requested by various
2099          * operations, so some operations that consume a few metadata will
2100          * succeed even if the Avail is zero. But this is better than the other
2101          * way around.
2102          */
2103         thresh = SZ_4M;
2104
2105         if (!mixed && total_free_meta - thresh < block_rsv->size)
2106                 buf->f_bavail = 0;
2107
2108         buf->f_type = BTRFS_SUPER_MAGIC;
2109         buf->f_bsize = dentry->d_sb->s_blocksize;
2110         buf->f_namelen = BTRFS_NAME_LEN;
2111
2112         /* We treat it as constant endianness (it doesn't matter _which_)
2113            because we want the fsid to come out the same whether mounted
2114            on a big-endian or little-endian host */
2115         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2116         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2117         /* Mask in the root object ID too, to disambiguate subvols */
2118         buf->f_fsid.val[0] ^=
2119                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2120         buf->f_fsid.val[1] ^=
2121                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2122
2123         return 0;
2124 }
2125
2126 static void btrfs_kill_super(struct super_block *sb)
2127 {
2128         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2129         kill_anon_super(sb);
2130         free_fs_info(fs_info);
2131 }
2132
2133 static struct file_system_type btrfs_fs_type = {
2134         .owner          = THIS_MODULE,
2135         .name           = "btrfs",
2136         .mount          = btrfs_mount,
2137         .kill_sb        = btrfs_kill_super,
2138         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2139 };
2140
2141 static struct file_system_type btrfs_root_fs_type = {
2142         .owner          = THIS_MODULE,
2143         .name           = "btrfs",
2144         .mount          = btrfs_mount_root,
2145         .kill_sb        = btrfs_kill_super,
2146         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2147 };
2148
2149 MODULE_ALIAS_FS("btrfs");
2150
2151 static int btrfs_control_open(struct inode *inode, struct file *file)
2152 {
2153         /*
2154          * The control file's private_data is used to hold the
2155          * transaction when it is started and is used to keep
2156          * track of whether a transaction is already in progress.
2157          */
2158         file->private_data = NULL;
2159         return 0;
2160 }
2161
2162 /*
2163  * used by btrfsctl to scan devices when no FS is mounted
2164  */
2165 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2166                                 unsigned long arg)
2167 {
2168         struct btrfs_ioctl_vol_args *vol;
2169         struct btrfs_device *device = NULL;
2170         int ret = -ENOTTY;
2171
2172         if (!capable(CAP_SYS_ADMIN))
2173                 return -EPERM;
2174
2175         vol = memdup_user((void __user *)arg, sizeof(*vol));
2176         if (IS_ERR(vol))
2177                 return PTR_ERR(vol);
2178         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2179
2180         switch (cmd) {
2181         case BTRFS_IOC_SCAN_DEV:
2182                 mutex_lock(&uuid_mutex);
2183                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2184                                                &btrfs_root_fs_type);
2185                 ret = PTR_ERR_OR_ZERO(device);
2186                 mutex_unlock(&uuid_mutex);
2187                 break;
2188         case BTRFS_IOC_FORGET_DEV:
2189                 ret = btrfs_forget_devices(vol->name);
2190                 break;
2191         case BTRFS_IOC_DEVICES_READY:
2192                 mutex_lock(&uuid_mutex);
2193                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2194                                                &btrfs_root_fs_type);
2195                 if (IS_ERR(device)) {
2196                         mutex_unlock(&uuid_mutex);
2197                         ret = PTR_ERR(device);
2198                         break;
2199                 }
2200                 ret = !(device->fs_devices->num_devices ==
2201                         device->fs_devices->total_devices);
2202                 mutex_unlock(&uuid_mutex);
2203                 break;
2204         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2205                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2206                 break;
2207         }
2208
2209         kfree(vol);
2210         return ret;
2211 }
2212
2213 static int btrfs_freeze(struct super_block *sb)
2214 {
2215         struct btrfs_trans_handle *trans;
2216         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2217         struct btrfs_root *root = fs_info->tree_root;
2218
2219         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2220         /*
2221          * We don't need a barrier here, we'll wait for any transaction that
2222          * could be in progress on other threads (and do delayed iputs that
2223          * we want to avoid on a frozen filesystem), or do the commit
2224          * ourselves.
2225          */
2226         trans = btrfs_attach_transaction_barrier(root);
2227         if (IS_ERR(trans)) {
2228                 /* no transaction, don't bother */
2229                 if (PTR_ERR(trans) == -ENOENT)
2230                         return 0;
2231                 return PTR_ERR(trans);
2232         }
2233         return btrfs_commit_transaction(trans);
2234 }
2235
2236 static int btrfs_unfreeze(struct super_block *sb)
2237 {
2238         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2239
2240         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2241         return 0;
2242 }
2243
2244 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2245 {
2246         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2247         struct btrfs_fs_devices *cur_devices;
2248         struct btrfs_device *dev, *first_dev = NULL;
2249         struct list_head *head;
2250
2251         /*
2252          * Lightweight locking of the devices. We should not need
2253          * device_list_mutex here as we only read the device data and the list
2254          * is protected by RCU.  Even if a device is deleted during the list
2255          * traversals, we'll get valid data, the freeing callback will wait at
2256          * least until the rcu_read_unlock.
2257          */
2258         rcu_read_lock();
2259         cur_devices = fs_info->fs_devices;
2260         while (cur_devices) {
2261                 head = &cur_devices->devices;
2262                 list_for_each_entry_rcu(dev, head, dev_list) {
2263                         if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
2264                                 continue;
2265                         if (!dev->name)
2266                                 continue;
2267                         if (!first_dev || dev->devid < first_dev->devid)
2268                                 first_dev = dev;
2269                 }
2270                 cur_devices = cur_devices->seed;
2271         }
2272
2273         if (first_dev)
2274                 seq_escape(m, rcu_str_deref(first_dev->name), " \t\n\\");
2275         else
2276                 WARN_ON(1);
2277         rcu_read_unlock();
2278         return 0;
2279 }
2280
2281 static const struct super_operations btrfs_super_ops = {
2282         .drop_inode     = btrfs_drop_inode,
2283         .evict_inode    = btrfs_evict_inode,
2284         .put_super      = btrfs_put_super,
2285         .sync_fs        = btrfs_sync_fs,
2286         .show_options   = btrfs_show_options,
2287         .show_devname   = btrfs_show_devname,
2288         .alloc_inode    = btrfs_alloc_inode,
2289         .destroy_inode  = btrfs_destroy_inode,
2290         .free_inode     = btrfs_free_inode,
2291         .statfs         = btrfs_statfs,
2292         .remount_fs     = btrfs_remount,
2293         .freeze_fs      = btrfs_freeze,
2294         .unfreeze_fs    = btrfs_unfreeze,
2295 };
2296
2297 static const struct file_operations btrfs_ctl_fops = {
2298         .open = btrfs_control_open,
2299         .unlocked_ioctl  = btrfs_control_ioctl,
2300         .compat_ioctl = btrfs_control_ioctl,
2301         .owner   = THIS_MODULE,
2302         .llseek = noop_llseek,
2303 };
2304
2305 static struct miscdevice btrfs_misc = {
2306         .minor          = BTRFS_MINOR,
2307         .name           = "btrfs-control",
2308         .fops           = &btrfs_ctl_fops
2309 };
2310
2311 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2312 MODULE_ALIAS("devname:btrfs-control");
2313
2314 static int __init btrfs_interface_init(void)
2315 {
2316         return misc_register(&btrfs_misc);
2317 }
2318
2319 static __cold void btrfs_interface_exit(void)
2320 {
2321         misc_deregister(&btrfs_misc);
2322 }
2323
2324 static void __init btrfs_print_mod_info(void)
2325 {
2326         static const char options[] = ""
2327 #ifdef CONFIG_BTRFS_DEBUG
2328                         ", debug=on"
2329 #endif
2330 #ifdef CONFIG_BTRFS_ASSERT
2331                         ", assert=on"
2332 #endif
2333 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2334                         ", integrity-checker=on"
2335 #endif
2336 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2337                         ", ref-verify=on"
2338 #endif
2339                         ;
2340         pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
2341 }
2342
2343 static int __init init_btrfs_fs(void)
2344 {
2345         int err;
2346
2347         btrfs_props_init();
2348
2349         err = btrfs_init_sysfs();
2350         if (err)
2351                 return err;
2352
2353         btrfs_init_compress();
2354
2355         err = btrfs_init_cachep();
2356         if (err)
2357                 goto free_compress;
2358
2359         err = extent_io_init();
2360         if (err)
2361                 goto free_cachep;
2362
2363         err = extent_map_init();
2364         if (err)
2365                 goto free_extent_io;
2366
2367         err = ordered_data_init();
2368         if (err)
2369                 goto free_extent_map;
2370
2371         err = btrfs_delayed_inode_init();
2372         if (err)
2373                 goto free_ordered_data;
2374
2375         err = btrfs_auto_defrag_init();
2376         if (err)
2377                 goto free_delayed_inode;
2378
2379         err = btrfs_delayed_ref_init();
2380         if (err)
2381                 goto free_auto_defrag;
2382
2383         err = btrfs_prelim_ref_init();
2384         if (err)
2385                 goto free_delayed_ref;
2386
2387         err = btrfs_end_io_wq_init();
2388         if (err)
2389                 goto free_prelim_ref;
2390
2391         err = btrfs_interface_init();
2392         if (err)
2393                 goto free_end_io_wq;
2394
2395         btrfs_init_lockdep();
2396
2397         btrfs_print_mod_info();
2398
2399         err = btrfs_run_sanity_tests();
2400         if (err)
2401                 goto unregister_ioctl;
2402
2403         err = register_filesystem(&btrfs_fs_type);
2404         if (err)
2405                 goto unregister_ioctl;
2406
2407         return 0;
2408
2409 unregister_ioctl:
2410         btrfs_interface_exit();
2411 free_end_io_wq:
2412         btrfs_end_io_wq_exit();
2413 free_prelim_ref:
2414         btrfs_prelim_ref_exit();
2415 free_delayed_ref:
2416         btrfs_delayed_ref_exit();
2417 free_auto_defrag:
2418         btrfs_auto_defrag_exit();
2419 free_delayed_inode:
2420         btrfs_delayed_inode_exit();
2421 free_ordered_data:
2422         ordered_data_exit();
2423 free_extent_map:
2424         extent_map_exit();
2425 free_extent_io:
2426         extent_io_exit();
2427 free_cachep:
2428         btrfs_destroy_cachep();
2429 free_compress:
2430         btrfs_exit_compress();
2431         btrfs_exit_sysfs();
2432
2433         return err;
2434 }
2435
2436 static void __exit exit_btrfs_fs(void)
2437 {
2438         btrfs_destroy_cachep();
2439         btrfs_delayed_ref_exit();
2440         btrfs_auto_defrag_exit();
2441         btrfs_delayed_inode_exit();
2442         btrfs_prelim_ref_exit();
2443         ordered_data_exit();
2444         extent_map_exit();
2445         extent_io_exit();
2446         btrfs_interface_exit();
2447         btrfs_end_io_wq_exit();
2448         unregister_filesystem(&btrfs_fs_type);
2449         btrfs_exit_sysfs();
2450         btrfs_cleanup_fs_uuids();
2451         btrfs_exit_compress();
2452 }
2453
2454 late_initcall(init_btrfs_fs);
2455 module_exit(exit_btrfs_fs)
2456
2457 MODULE_LICENSE("GPL");
2458 MODULE_SOFTDEP("pre: crc32c");