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/ratelimit.h>
  27 #include <linux/crc32c.h>
  28 #include <linux/btrfs.h>
  29 #include "delayed-inode.h"
  30 #include "ctree.h"
  31 #include "disk-io.h"
  32 #include "transaction.h"
  33 #include "btrfs_inode.h"
  34 #include "print-tree.h"
  35 #include "props.h"
  36 #include "xattr.h"
  37 #include "volumes.h"
  38 #include "export.h"
  39 #include "compression.h"
  40 #include "rcu-string.h"
  41 #include "dev-replace.h"
  42 #include "free-space-cache.h"
  43 #include "backref.h"
  44 #include "space-info.h"
  45 #include "sysfs.h"
  46 #include "zoned.h"
  47 #include "tests/btrfs-tests.h"
  48 #include "block-group.h"
  49 #include "discard.h"
  50 #include "qgroup.h"
  51 #include "raid56.h"
  52 #define CREATE_TRACE_POINTS
  53 #include <trace/events/btrfs.h>
  54
  55 static const struct super_operations btrfs_super_ops;
  56
  57 /*
  58  * Types for mounting the default subvolume and a subvolume explicitly
  59  * requested by subvol=/path. That way the callchain is straightforward and we
  60  * don't have to play tricks with the mount options and recursive calls to
  61  * btrfs_mount.
  62  *
  63  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
  64  */
  65 static struct file_system_type btrfs_fs_type;
  66 static struct file_system_type btrfs_root_fs_type;
  67
  68 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  69
  70 #ifdef CONFIG_PRINTK
  71
  72 #define STATE_STRING_PREFACE    ": state "
  73 #define STATE_STRING_BUF_LEN    (sizeof(STATE_STRING_PREFACE) + BTRFS_FS_STATE_COUNT)
  74
  75 /*
  76  * Characters to print to indicate error conditions or uncommon filesystem state.
  77  * RO is not an error.
  78  */
  79 static const char fs_state_chars[] = {
  80         [BTRFS_FS_STATE_ERROR]                  = 'E',
  81         [BTRFS_FS_STATE_REMOUNTING]             = 'M',
  82         [BTRFS_FS_STATE_RO]                     = 0,
  83         [BTRFS_FS_STATE_TRANS_ABORTED]          = 'A',
  84         [BTRFS_FS_STATE_DEV_REPLACING]          = 'R',
  85         [BTRFS_FS_STATE_DUMMY_FS_INFO]          = 0,
  86         [BTRFS_FS_STATE_NO_CSUMS]               = 'C',
  87         [BTRFS_FS_STATE_LOG_CLEANUP_ERROR]      = 'L',
  88 };
  89
  90 static void btrfs_state_to_string(const struct btrfs_fs_info *info, char *buf)
  91 {
  92         unsigned int bit;
  93         bool states_printed = false;
  94         unsigned long fs_state = READ_ONCE(info->fs_state);
  95         char *curr = buf;
  96
  97         memcpy(curr, STATE_STRING_PREFACE, sizeof(STATE_STRING_PREFACE));
  98         curr += sizeof(STATE_STRING_PREFACE) - 1;
  99
 100         for_each_set_bit(bit, &fs_state, sizeof(fs_state)) {
 101                 WARN_ON_ONCE(bit >= BTRFS_FS_STATE_COUNT);
 102                 if ((bit < BTRFS_FS_STATE_COUNT) && fs_state_chars[bit]) {
 103                         *curr++ = fs_state_chars[bit];
 104                         states_printed = true;
 105                 }
 106         }
 107
 108         /* If no states were printed, reset the buffer */
 109         if (!states_printed)
 110                 curr = buf;
 111
 112         *curr++ = 0;
 113 }
 114 #endif
 115
 116 /*
 117  * Generally the error codes correspond to their respective errors, but there
 118  * are a few special cases.
 119  *
 120  * EUCLEAN: Any sort of corruption that we encounter.  The tree-checker for
 121  *          instance will return EUCLEAN if any of the blocks are corrupted in
 122  *          a way that is problematic.  We want to reserve EUCLEAN for these
 123  *          sort of corruptions.
 124  *
 125  * EROFS: If we check BTRFS_FS_STATE_ERROR and fail out with a return error, we
 126  *        need to use EROFS for this case.  We will have no idea of the
 127  *        original failure, that will have been reported at the time we tripped
 128  *        over the error.  Each subsequent error that doesn't have any context
 129  *        of the original error should use EROFS when handling BTRFS_FS_STATE_ERROR.
 130  */
 131 const char * __attribute_const__ btrfs_decode_error(int errno)
 132 {
 133         char *errstr = "unknown";
 134
 135         switch (errno) {
 136         case -ENOENT:           /* -2 */
 137                 errstr = "No such entry";
 138                 break;
 139         case -EIO:              /* -5 */
 140                 errstr = "IO failure";
 141                 break;
 142         case -ENOMEM:           /* -12*/
 143                 errstr = "Out of memory";
 144                 break;
 145         case -EEXIST:           /* -17 */
 146                 errstr = "Object already exists";
 147                 break;
 148         case -ENOSPC:           /* -28 */
 149                 errstr = "No space left";
 150                 break;
 151         case -EROFS:            /* -30 */
 152                 errstr = "Readonly filesystem";
 153                 break;
 154         case -EOPNOTSUPP:       /* -95 */
 155                 errstr = "Operation not supported";
 156                 break;
 157         case -EUCLEAN:          /* -117 */
 158                 errstr = "Filesystem corrupted";
 159                 break;
 160         case -EDQUOT:           /* -122 */
 161                 errstr = "Quota exceeded";
 162                 break;
 163         }
 164
 165         return errstr;
 166 }
 167
 168 /*
 169  * __btrfs_handle_fs_error decodes expected errors from the caller and
 170  * invokes the appropriate error response.
 171  */
 172 __cold
 173 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 174                        unsigned int line, int errno, const char *fmt, ...)
 175 {
 176         struct super_block *sb = fs_info->sb;
 177 #ifdef CONFIG_PRINTK
 178         char statestr[STATE_STRING_BUF_LEN];
 179         const char *errstr;
 180 #endif
 181
 182         /*
 183          * Special case: if the error is EROFS, and we're already
 184          * under SB_RDONLY, then it is safe here.
 185          */
 186         if (errno == -EROFS && sb_rdonly(sb))
 187                 return;
 188
 189 #ifdef CONFIG_PRINTK
 190         errstr = btrfs_decode_error(errno);
 191         btrfs_state_to_string(fs_info, statestr);
 192         if (fmt) {
 193                 struct va_format vaf;
 194                 va_list args;
 195
 196                 va_start(args, fmt);
 197                 vaf.fmt = fmt;
 198                 vaf.va = &args;
 199
 200                 pr_crit("BTRFS: error (device %s%s) in %s:%d: errno=%d %s (%pV)\n",
 201                         sb->s_id, statestr, function, line, errno, errstr, &vaf);
 202                 va_end(args);
 203         } else {
 204                 pr_crit("BTRFS: error (device %s%s) in %s:%d: errno=%d %s\n",
 205                         sb->s_id, statestr, function, line, errno, errstr);
 206         }
 207 #endif
 208
 209         /*
 210          * Today we only save the error info to memory.  Long term we'll
 211          * also send it down to the disk
 212          */
 213         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 214
 215         /* Don't go through full error handling during mount */
 216         if (!(sb->s_flags & SB_BORN))
 217                 return;
 218
 219         if (sb_rdonly(sb))
 220                 return;
 221
 222         btrfs_discard_stop(fs_info);
 223
 224         /* btrfs handle error by forcing the filesystem readonly */
 225         btrfs_set_sb_rdonly(sb);
 226         btrfs_info(fs_info, "forced readonly");
 227         /*
 228          * Note that a running device replace operation is not canceled here
 229          * although there is no way to update the progress. It would add the
 230          * risk of a deadlock, therefore the canceling is omitted. The only
 231          * penalty is that some I/O remains active until the procedure
 232          * completes. The next time when the filesystem is mounted writable
 233          * again, the device replace operation continues.
 234          */
 235 }
 236
 237 #ifdef CONFIG_PRINTK
 238 static const char * const logtypes[] = {
 239         "emergency",
 240         "alert",
 241         "critical",
 242         "error",
 243         "warning",
 244         "notice",
 245         "info",
 246         "debug",
 247 };
 248
 249
 250 /*
 251  * Use one ratelimit state per log level so that a flood of less important
 252  * messages doesn't cause more important ones to be dropped.
 253  */
 254 static struct ratelimit_state printk_limits[] = {
 255         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 256         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 257         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 258         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 259         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 260         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 261         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 262         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 263 };
 264
 265 void __cold _btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 266 {
 267         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
 268         struct va_format vaf;
 269         va_list args;
 270         int kern_level;
 271         const char *type = logtypes[4];
 272         struct ratelimit_state *ratelimit = &printk_limits[4];
 273
 274         va_start(args, fmt);
 275
 276         while ((kern_level = printk_get_level(fmt)) != 0) {
 277                 size_t size = printk_skip_level(fmt) - fmt;
 278
 279                 if (kern_level >= '0' && kern_level <= '7') {
 280                         memcpy(lvl, fmt,  size);
 281                         lvl[size] = '\0';
 282                         type = logtypes[kern_level - '0'];
 283                         ratelimit = &printk_limits[kern_level - '0'];
 284                 }
 285                 fmt += size;
 286         }
 287
 288         vaf.fmt = fmt;
 289         vaf.va = &args;
 290
 291         if (__ratelimit(ratelimit)) {
 292                 if (fs_info) {
 293                         char statestr[STATE_STRING_BUF_LEN];
 294
 295                         btrfs_state_to_string(fs_info, statestr);
 296                         _printk("%sBTRFS %s (device %s%s): %pV\n", lvl, type,
 297                                 fs_info->sb->s_id, statestr, &vaf);
 298                 } else {
 299                         _printk("%sBTRFS %s: %pV\n", lvl, type, &vaf);
 300                 }
 301         }
 302
 303         va_end(args);
 304 }
 305 #endif
 306
 307 #if BITS_PER_LONG == 32
 308 void __cold btrfs_warn_32bit_limit(struct btrfs_fs_info *fs_info)
 309 {
 310         if (!test_and_set_bit(BTRFS_FS_32BIT_WARN, &fs_info->flags)) {
 311                 btrfs_warn(fs_info, "reaching 32bit limit for logical addresses");
 312                 btrfs_warn(fs_info,
 313 "due to page cache limit on 32bit systems, btrfs can't access metadata at or beyond %lluT",
 314                            BTRFS_32BIT_MAX_FILE_SIZE >> 40);
 315                 btrfs_warn(fs_info,
 316                            "please consider upgrading to 64bit kernel/hardware");
 317         }
 318 }
 319
 320 void __cold btrfs_err_32bit_limit(struct btrfs_fs_info *fs_info)
 321 {
 322         if (!test_and_set_bit(BTRFS_FS_32BIT_ERROR, &fs_info->flags)) {
 323                 btrfs_err(fs_info, "reached 32bit limit for logical addresses");
 324                 btrfs_err(fs_info,
 325 "due to page cache limit on 32bit systems, metadata beyond %lluT can't be accessed",
 326                           BTRFS_32BIT_MAX_FILE_SIZE >> 40);
 327                 btrfs_err(fs_info,
 328                            "please consider upgrading to 64bit kernel/hardware");
 329         }
 330 }
 331 #endif
 332
 333 /*
 334  * We only mark the transaction aborted and then set the file system read-only.
 335  * This will prevent new transactions from starting or trying to join this
 336  * one.
 337  *
 338  * This means that error recovery at the call site is limited to freeing
 339  * any local memory allocations and passing the error code up without
 340  * further cleanup. The transaction should complete as it normally would
 341  * in the call path but will return -EIO.
 342  *
 343  * We'll complete the cleanup in btrfs_end_transaction and
 344  * btrfs_commit_transaction.
 345  */
 346 __cold
 347 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 348                                const char *function,
 349                                unsigned int line, int errno)
 350 {
 351         struct btrfs_fs_info *fs_info = trans->fs_info;
 352
 353         WRITE_ONCE(trans->aborted, errno);
 354         WRITE_ONCE(trans->transaction->aborted, errno);
 355         /* Wake up anybody who may be waiting on this transaction */
 356         wake_up(&fs_info->transaction_wait);
 357         wake_up(&fs_info->transaction_blocked_wait);
 358         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 359 }
 360 /*
 361  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 362  * issues an alert, and either panics or BUGs, depending on mount options.
 363  */
 364 __cold
 365 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 366                    unsigned int line, int errno, const char *fmt, ...)
 367 {
 368         char *s_id = "<unknown>";
 369         const char *errstr;
 370         struct va_format vaf = { .fmt = fmt };
 371         va_list args;
 372
 373         if (fs_info)
 374                 s_id = fs_info->sb->s_id;
 375
 376         va_start(args, fmt);
 377         vaf.va = &args;
 378
 379         errstr = btrfs_decode_error(errno);
 380         if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
 381                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 382                         s_id, function, line, &vaf, errno, errstr);
 383
 384         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 385                    function, line, &vaf, errno, errstr);
 386         va_end(args);
 387         /* Caller calls BUG() */
 388 }
 389
 390 static void btrfs_put_super(struct super_block *sb)
 391 {
 392         close_ctree(btrfs_sb(sb));
 393 }
 394
 395 enum {
 396         Opt_acl, Opt_noacl,
 397         Opt_clear_cache,
 398         Opt_commit_interval,
 399         Opt_compress,
 400         Opt_compress_force,
 401         Opt_compress_force_type,
 402         Opt_compress_type,
 403         Opt_degraded,
 404         Opt_device,
 405         Opt_fatal_errors,
 406         Opt_flushoncommit, Opt_noflushoncommit,
 407         Opt_max_inline,
 408         Opt_barrier, Opt_nobarrier,
 409         Opt_datacow, Opt_nodatacow,
 410         Opt_datasum, Opt_nodatasum,
 411         Opt_defrag, Opt_nodefrag,
 412         Opt_discard, Opt_nodiscard,
 413         Opt_discard_mode,
 414         Opt_norecovery,
 415         Opt_ratio,
 416         Opt_rescan_uuid_tree,
 417         Opt_skip_balance,
 418         Opt_space_cache, Opt_no_space_cache,
 419         Opt_space_cache_version,
 420         Opt_ssd, Opt_nossd,
 421         Opt_ssd_spread, Opt_nossd_spread,
 422         Opt_subvol,
 423         Opt_subvol_empty,
 424         Opt_subvolid,
 425         Opt_thread_pool,
 426         Opt_treelog, Opt_notreelog,
 427         Opt_user_subvol_rm_allowed,
 428
 429         /* Rescue options */
 430         Opt_rescue,
 431         Opt_usebackuproot,
 432         Opt_nologreplay,
 433         Opt_ignorebadroots,
 434         Opt_ignoredatacsums,
 435         Opt_rescue_all,
 436
 437         /* Deprecated options */
 438         Opt_recovery,
 439         Opt_inode_cache, Opt_noinode_cache,
 440
 441         /* Debugging options */
 442         Opt_check_integrity,
 443         Opt_check_integrity_including_extent_data,
 444         Opt_check_integrity_print_mask,
 445         Opt_enospc_debug, Opt_noenospc_debug,
 446 #ifdef CONFIG_BTRFS_DEBUG
 447         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 448 #endif
 449 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 450         Opt_ref_verify,
 451 #endif
 452         Opt_err,
 453 };
 454
 455 static const match_table_t tokens = {
 456         {Opt_acl, "acl"},
 457         {Opt_noacl, "noacl"},
 458         {Opt_clear_cache, "clear_cache"},
 459         {Opt_commit_interval, "commit=%u"},
 460         {Opt_compress, "compress"},
 461         {Opt_compress_type, "compress=%s"},
 462         {Opt_compress_force, "compress-force"},
 463         {Opt_compress_force_type, "compress-force=%s"},
 464         {Opt_degraded, "degraded"},
 465         {Opt_device, "device=%s"},
 466         {Opt_fatal_errors, "fatal_errors=%s"},
 467         {Opt_flushoncommit, "flushoncommit"},
 468         {Opt_noflushoncommit, "noflushoncommit"},
 469         {Opt_inode_cache, "inode_cache"},
 470         {Opt_noinode_cache, "noinode_cache"},
 471         {Opt_max_inline, "max_inline=%s"},
 472         {Opt_barrier, "barrier"},
 473         {Opt_nobarrier, "nobarrier"},
 474         {Opt_datacow, "datacow"},
 475         {Opt_nodatacow, "nodatacow"},
 476         {Opt_datasum, "datasum"},
 477         {Opt_nodatasum, "nodatasum"},
 478         {Opt_defrag, "autodefrag"},
 479         {Opt_nodefrag, "noautodefrag"},
 480         {Opt_discard, "discard"},
 481         {Opt_discard_mode, "discard=%s"},
 482         {Opt_nodiscard, "nodiscard"},
 483         {Opt_norecovery, "norecovery"},
 484         {Opt_ratio, "metadata_ratio=%u"},
 485         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 486         {Opt_skip_balance, "skip_balance"},
 487         {Opt_space_cache, "space_cache"},
 488         {Opt_no_space_cache, "nospace_cache"},
 489         {Opt_space_cache_version, "space_cache=%s"},
 490         {Opt_ssd, "ssd"},
 491         {Opt_nossd, "nossd"},
 492         {Opt_ssd_spread, "ssd_spread"},
 493         {Opt_nossd_spread, "nossd_spread"},
 494         {Opt_subvol, "subvol=%s"},
 495         {Opt_subvol_empty, "subvol="},
 496         {Opt_subvolid, "subvolid=%s"},
 497         {Opt_thread_pool, "thread_pool=%u"},
 498         {Opt_treelog, "treelog"},
 499         {Opt_notreelog, "notreelog"},
 500         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 501
 502         /* Rescue options */
 503         {Opt_rescue, "rescue=%s"},
 504         /* Deprecated, with alias rescue=nologreplay */
 505         {Opt_nologreplay, "nologreplay"},
 506         /* Deprecated, with alias rescue=usebackuproot */
 507         {Opt_usebackuproot, "usebackuproot"},
 508
 509         /* Deprecated options */
 510         {Opt_recovery, "recovery"},
 511
 512         /* Debugging options */
 513         {Opt_check_integrity, "check_int"},
 514         {Opt_check_integrity_including_extent_data, "check_int_data"},
 515         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
 516         {Opt_enospc_debug, "enospc_debug"},
 517         {Opt_noenospc_debug, "noenospc_debug"},
 518 #ifdef CONFIG_BTRFS_DEBUG
 519         {Opt_fragment_data, "fragment=data"},
 520         {Opt_fragment_metadata, "fragment=metadata"},
 521         {Opt_fragment_all, "fragment=all"},
 522 #endif
 523 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 524         {Opt_ref_verify, "ref_verify"},
 525 #endif
 526         {Opt_err, NULL},
 527 };
 528
 529 static const match_table_t rescue_tokens = {
 530         {Opt_usebackuproot, "usebackuproot"},
 531         {Opt_nologreplay, "nologreplay"},
 532         {Opt_ignorebadroots, "ignorebadroots"},
 533         {Opt_ignorebadroots, "ibadroots"},
 534         {Opt_ignoredatacsums, "ignoredatacsums"},
 535         {Opt_ignoredatacsums, "idatacsums"},
 536         {Opt_rescue_all, "all"},
 537         {Opt_err, NULL},
 538 };
 539
 540 static bool check_ro_option(struct btrfs_fs_info *fs_info, unsigned long opt,
 541                             const char *opt_name)
 542 {
 543         if (fs_info->mount_opt & opt) {
 544                 btrfs_err(fs_info, "%s must be used with ro mount option",
 545                           opt_name);
 546                 return true;
 547         }
 548         return false;
 549 }
 550
 551 static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
 552 {
 553         char *opts;
 554         char *orig;
 555         char *p;
 556         substring_t args[MAX_OPT_ARGS];
 557         int ret = 0;
 558
 559         opts = kstrdup(options, GFP_KERNEL);
 560         if (!opts)
 561                 return -ENOMEM;
 562         orig = opts;
 563
 564         while ((p = strsep(&opts, ":")) != NULL) {
 565                 int token;
 566
 567                 if (!*p)
 568                         continue;
 569                 token = match_token(p, rescue_tokens, args);
 570                 switch (token){
 571                 case Opt_usebackuproot:
 572                         btrfs_info(info,
 573                                    "trying to use backup root at mount time");
 574                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 575                         break;
 576                 case Opt_nologreplay:
 577                         btrfs_set_and_info(info, NOLOGREPLAY,
 578                                            "disabling log replay at mount time");
 579                         break;
 580                 case Opt_ignorebadroots:
 581                         btrfs_set_and_info(info, IGNOREBADROOTS,
 582                                            "ignoring bad roots");
 583                         break;
 584                 case Opt_ignoredatacsums:
 585                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 586                                            "ignoring data csums");
 587                         break;
 588                 case Opt_rescue_all:
 589                         btrfs_info(info, "enabling all of the rescue options");
 590                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 591                                            "ignoring data csums");
 592                         btrfs_set_and_info(info, IGNOREBADROOTS,
 593                                            "ignoring bad roots");
 594                         btrfs_set_and_info(info, NOLOGREPLAY,
 595                                            "disabling log replay at mount time");
 596                         break;
 597                 case Opt_err:
 598                         btrfs_info(info, "unrecognized rescue option '%s'", p);
 599                         ret = -EINVAL;
 600                         goto out;
 601                 default:
 602                         break;
 603                 }
 604
 605         }
 606 out:
 607         kfree(orig);
 608         return ret;
 609 }
 610
 611 /*
 612  * Regular mount options parser.  Everything that is needed only when
 613  * reading in a new superblock is parsed here.
 614  * XXX JDM: This needs to be cleaned up for remount.
 615  */
 616 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 617                         unsigned long new_flags)
 618 {
 619         substring_t args[MAX_OPT_ARGS];
 620         char *p, *num;
 621         int intarg;
 622         int ret = 0;
 623         char *compress_type;
 624         bool compress_force = false;
 625         enum btrfs_compression_type saved_compress_type;
 626         int saved_compress_level;
 627         bool saved_compress_force;
 628         int no_compress = 0;
 629
 630         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 631                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 632         else if (btrfs_free_space_cache_v1_active(info)) {
 633                 if (btrfs_is_zoned(info)) {
 634                         btrfs_info(info,
 635                         "zoned: clearing existing space cache");
 636                         btrfs_set_super_cache_generation(info->super_copy, 0);
 637                 } else {
 638                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 639                 }
 640         }
 641
 642         /*
 643          * Even the options are empty, we still need to do extra check
 644          * against new flags
 645          */
 646         if (!options)
 647                 goto check;
 648
 649         while ((p = strsep(&options, ",")) != NULL) {
 650                 int token;
 651                 if (!*p)
 652                         continue;
 653
 654                 token = match_token(p, tokens, args);
 655                 switch (token) {
 656                 case Opt_degraded:
 657                         btrfs_info(info, "allowing degraded mounts");
 658                         btrfs_set_opt(info->mount_opt, DEGRADED);
 659                         break;
 660                 case Opt_subvol:
 661                 case Opt_subvol_empty:
 662                 case Opt_subvolid:
 663                 case Opt_device:
 664                         /*
 665                          * These are parsed by btrfs_parse_subvol_options or
 666                          * btrfs_parse_device_options and can be ignored here.
 667                          */
 668                         break;
 669                 case Opt_nodatasum:
 670                         btrfs_set_and_info(info, NODATASUM,
 671                                            "setting nodatasum");
 672                         break;
 673                 case Opt_datasum:
 674                         if (btrfs_test_opt(info, NODATASUM)) {
 675                                 if (btrfs_test_opt(info, NODATACOW))
 676                                         btrfs_info(info,
 677                                                    "setting datasum, datacow enabled");
 678                                 else
 679                                         btrfs_info(info, "setting datasum");
 680                         }
 681                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 682                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 683                         break;
 684                 case Opt_nodatacow:
 685                         if (!btrfs_test_opt(info, NODATACOW)) {
 686                                 if (!btrfs_test_opt(info, COMPRESS) ||
 687                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 688                                         btrfs_info(info,
 689                                                    "setting nodatacow, compression disabled");
 690                                 } else {
 691                                         btrfs_info(info, "setting nodatacow");
 692                                 }
 693                         }
 694                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 695                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 696                         btrfs_set_opt(info->mount_opt, NODATACOW);
 697                         btrfs_set_opt(info->mount_opt, NODATASUM);
 698                         break;
 699                 case Opt_datacow:
 700                         btrfs_clear_and_info(info, NODATACOW,
 701                                              "setting datacow");
 702                         break;
 703                 case Opt_compress_force:
 704                 case Opt_compress_force_type:
 705                         compress_force = true;
 706                         fallthrough;
 707                 case Opt_compress:
 708                 case Opt_compress_type:
 709                         saved_compress_type = btrfs_test_opt(info,
 710                                                              COMPRESS) ?
 711                                 info->compress_type : BTRFS_COMPRESS_NONE;
 712                         saved_compress_force =
 713                                 btrfs_test_opt(info, FORCE_COMPRESS);
 714                         saved_compress_level = info->compress_level;
 715                         if (token == Opt_compress ||
 716                             token == Opt_compress_force ||
 717                             strncmp(args[0].from, "zlib", 4) == 0) {
 718                                 compress_type = "zlib";
 719
 720                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 721                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 722                                 /*
 723                                  * args[0] contains uninitialized data since
 724                                  * for these tokens we don't expect any
 725                                  * parameter.
 726                                  */
 727                                 if (token != Opt_compress &&
 728                                     token != Opt_compress_force)
 729                                         info->compress_level =
 730                                           btrfs_compress_str2level(
 731                                                         BTRFS_COMPRESS_ZLIB,
 732                                                         args[0].from + 4);
 733                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 734                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 735                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 736                                 no_compress = 0;
 737                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 738                                 compress_type = "lzo";
 739                                 info->compress_type = BTRFS_COMPRESS_LZO;
 740                                 info->compress_level = 0;
 741                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 742                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 743                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 744                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 745                                 no_compress = 0;
 746                         } else if (strncmp(args[0].from, "zstd", 4) == 0) {
 747                                 compress_type = "zstd";
 748                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 749                                 info->compress_level =
 750                                         btrfs_compress_str2level(
 751                                                          BTRFS_COMPRESS_ZSTD,
 752                                                          args[0].from + 4);
 753                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 754                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 755                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 756                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 757                                 no_compress = 0;
 758                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 759                                 compress_type = "no";
 760                                 info->compress_level = 0;
 761                                 info->compress_type = 0;
 762                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 763                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 764                                 compress_force = false;
 765                                 no_compress++;
 766                         } else {
 767                                 btrfs_err(info, "unrecognized compression value %s",
 768                                           args[0].from);
 769                                 ret = -EINVAL;
 770                                 goto out;
 771                         }
 772
 773                         if (compress_force) {
 774                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 775                         } else {
 776                                 /*
 777                                  * If we remount from compress-force=xxx to
 778                                  * compress=xxx, we need clear FORCE_COMPRESS
 779                                  * flag, otherwise, there is no way for users
 780                                  * to disable forcible compression separately.
 781                                  */
 782                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 783                         }
 784                         if (no_compress == 1) {
 785                                 btrfs_info(info, "use no compression");
 786                         } else if ((info->compress_type != saved_compress_type) ||
 787                                    (compress_force != saved_compress_force) ||
 788                                    (info->compress_level != saved_compress_level)) {
 789                                 btrfs_info(info, "%s %s compression, level %d",
 790                                            (compress_force) ? "force" : "use",
 791                                            compress_type, info->compress_level);
 792                         }
 793                         compress_force = false;
 794                         break;
 795                 case Opt_ssd:
 796                         btrfs_set_and_info(info, SSD,
 797                                            "enabling ssd optimizations");
 798                         btrfs_clear_opt(info->mount_opt, NOSSD);
 799                         break;
 800                 case Opt_ssd_spread:
 801                         btrfs_set_and_info(info, SSD,
 802                                            "enabling ssd optimizations");
 803                         btrfs_set_and_info(info, SSD_SPREAD,
 804                                            "using spread ssd allocation scheme");
 805                         btrfs_clear_opt(info->mount_opt, NOSSD);
 806                         break;
 807                 case Opt_nossd:
 808                         btrfs_set_opt(info->mount_opt, NOSSD);
 809                         btrfs_clear_and_info(info, SSD,
 810                                              "not using ssd optimizations");
 811                         fallthrough;
 812                 case Opt_nossd_spread:
 813                         btrfs_clear_and_info(info, SSD_SPREAD,
 814                                              "not using spread ssd allocation scheme");
 815                         break;
 816                 case Opt_barrier:
 817                         btrfs_clear_and_info(info, NOBARRIER,
 818                                              "turning on barriers");
 819                         break;
 820                 case Opt_nobarrier:
 821                         btrfs_set_and_info(info, NOBARRIER,
 822                                            "turning off barriers");
 823                         break;
 824                 case Opt_thread_pool:
 825                         ret = match_int(&args[0], &intarg);
 826                         if (ret) {
 827                                 btrfs_err(info, "unrecognized thread_pool value %s",
 828                                           args[0].from);
 829                                 goto out;
 830                         } else if (intarg == 0) {
 831                                 btrfs_err(info, "invalid value 0 for thread_pool");
 832                                 ret = -EINVAL;
 833                                 goto out;
 834                         }
 835                         info->thread_pool_size = intarg;
 836                         break;
 837                 case Opt_max_inline:
 838                         num = match_strdup(&args[0]);
 839                         if (num) {
 840                                 info->max_inline = memparse(num, NULL);
 841                                 kfree(num);
 842
 843                                 if (info->max_inline) {
 844                                         info->max_inline = min_t(u64,
 845                                                 info->max_inline,
 846                                                 info->sectorsize);
 847                                 }
 848                                 btrfs_info(info, "max_inline at %llu",
 849                                            info->max_inline);
 850                         } else {
 851                                 ret = -ENOMEM;
 852                                 goto out;
 853                         }
 854                         break;
 855                 case Opt_acl:
 856 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 857                         info->sb->s_flags |= SB_POSIXACL;
 858                         break;
 859 #else
 860                         btrfs_err(info, "support for ACL not compiled in!");
 861                         ret = -EINVAL;
 862                         goto out;
 863 #endif
 864                 case Opt_noacl:
 865                         info->sb->s_flags &= ~SB_POSIXACL;
 866                         break;
 867                 case Opt_notreelog:
 868                         btrfs_set_and_info(info, NOTREELOG,
 869                                            "disabling tree log");
 870                         break;
 871                 case Opt_treelog:
 872                         btrfs_clear_and_info(info, NOTREELOG,
 873                                              "enabling tree log");
 874                         break;
 875                 case Opt_norecovery:
 876                 case Opt_nologreplay:
 877                         btrfs_warn(info,
 878                 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
 879                         btrfs_set_and_info(info, NOLOGREPLAY,
 880                                            "disabling log replay at mount time");
 881                         break;
 882                 case Opt_flushoncommit:
 883                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 884                                            "turning on flush-on-commit");
 885                         break;
 886                 case Opt_noflushoncommit:
 887                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 888                                              "turning off flush-on-commit");
 889                         break;
 890                 case Opt_ratio:
 891                         ret = match_int(&args[0], &intarg);
 892                         if (ret) {
 893                                 btrfs_err(info, "unrecognized metadata_ratio value %s",
 894                                           args[0].from);
 895                                 goto out;
 896                         }
 897                         info->metadata_ratio = intarg;
 898                         btrfs_info(info, "metadata ratio %u",
 899                                    info->metadata_ratio);
 900                         break;
 901                 case Opt_discard:
 902                 case Opt_discard_mode:
 903                         if (token == Opt_discard ||
 904                             strcmp(args[0].from, "sync") == 0) {
 905                                 btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
 906                                 btrfs_set_and_info(info, DISCARD_SYNC,
 907                                                    "turning on sync discard");
 908                         } else if (strcmp(args[0].from, "async") == 0) {
 909                                 btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
 910                                 btrfs_set_and_info(info, DISCARD_ASYNC,
 911                                                    "turning on async discard");
 912                         } else {
 913                                 btrfs_err(info, "unrecognized discard mode value %s",
 914                                           args[0].from);
 915                                 ret = -EINVAL;
 916                                 goto out;
 917                         }
 918                         break;
 919                 case Opt_nodiscard:
 920                         btrfs_clear_and_info(info, DISCARD_SYNC,
 921                                              "turning off discard");
 922                         btrfs_clear_and_info(info, DISCARD_ASYNC,
 923                                              "turning off async discard");
 924                         break;
 925                 case Opt_space_cache:
 926                 case Opt_space_cache_version:
 927                         /*
 928                          * We already set FREE_SPACE_TREE above because we have
 929                          * compat_ro(FREE_SPACE_TREE) set, and we aren't going
 930                          * to allow v1 to be set for extent tree v2, simply
 931                          * ignore this setting if we're extent tree v2.
 932                          */
 933                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 934                                 break;
 935                         if (token == Opt_space_cache ||
 936                             strcmp(args[0].from, "v1") == 0) {
 937                                 btrfs_clear_opt(info->mount_opt,
 938                                                 FREE_SPACE_TREE);
 939                                 btrfs_set_and_info(info, SPACE_CACHE,
 940                                            "enabling disk space caching");
 941                         } else if (strcmp(args[0].from, "v2") == 0) {
 942                                 btrfs_clear_opt(info->mount_opt,
 943                                                 SPACE_CACHE);
 944                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 945                                                    "enabling free space tree");
 946                         } else {
 947                                 btrfs_err(info, "unrecognized space_cache value %s",
 948                                           args[0].from);
 949                                 ret = -EINVAL;
 950                                 goto out;
 951                         }
 952                         break;
 953                 case Opt_rescan_uuid_tree:
 954                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 955                         break;
 956                 case Opt_no_space_cache:
 957                         /*
 958                          * We cannot operate without the free space tree with
 959                          * extent tree v2, ignore this option.
 960                          */
 961                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 962                                 break;
 963                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 964                                 btrfs_clear_and_info(info, SPACE_CACHE,
 965                                              "disabling disk space caching");
 966                         }
 967                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 968                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 969                                              "disabling free space tree");
 970                         }
 971                         break;
 972                 case Opt_inode_cache:
 973                 case Opt_noinode_cache:
 974                         btrfs_warn(info,
 975         "the 'inode_cache' option is deprecated and has no effect since 5.11");
 976                         break;
 977                 case Opt_clear_cache:
 978                         /*
 979                          * We cannot clear the free space tree with extent tree
 980                          * v2, ignore this option.
 981                          */
 982                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 983                                 break;
 984                         btrfs_set_and_info(info, CLEAR_CACHE,
 985                                            "force clearing of disk cache");
 986                         break;
 987                 case Opt_user_subvol_rm_allowed:
 988                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 989                         break;
 990                 case Opt_enospc_debug:
 991                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 992                         break;
 993                 case Opt_noenospc_debug:
 994                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 995                         break;
 996                 case Opt_defrag:
 997                         btrfs_set_and_info(info, AUTO_DEFRAG,
 998                                            "enabling auto defrag");
 999                         break;
1000                 case Opt_nodefrag:
1001                         btrfs_clear_and_info(info, AUTO_DEFRAG,
1002                                              "disabling auto defrag");
1003                         break;
1004                 case Opt_recovery:
1005                 case Opt_usebackuproot:
1006                         btrfs_warn(info,
1007                         "'%s' is deprecated, use 'rescue=usebackuproot' instead",
1008                                    token == Opt_recovery ? "recovery" :
1009                                    "usebackuproot");
1010                         btrfs_info(info,
1011                                    "trying to use backup root at mount time");
1012                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
1013                         break;
1014                 case Opt_skip_balance:
1015                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
1016                         break;
1017 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1018                 case Opt_check_integrity_including_extent_data:
1019                         btrfs_info(info,
1020                                    "enabling check integrity including extent data");
1021                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY_DATA);
1022                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
1023                         break;
1024                 case Opt_check_integrity:
1025                         btrfs_info(info, "enabling check integrity");
1026                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
1027                         break;
1028                 case Opt_check_integrity_print_mask:
1029                         ret = match_int(&args[0], &intarg);
1030                         if (ret) {
1031                                 btrfs_err(info,
1032                                 "unrecognized check_integrity_print_mask value %s",
1033                                         args[0].from);
1034                                 goto out;
1035                         }
1036                         info->check_integrity_print_mask = intarg;
1037                         btrfs_info(info, "check_integrity_print_mask 0x%x",
1038                                    info->check_integrity_print_mask);
1039                         break;
1040 #else
1041                 case Opt_check_integrity_including_extent_data:
1042                 case Opt_check_integrity:
1043                 case Opt_check_integrity_print_mask:
1044                         btrfs_err(info,
1045                                   "support for check_integrity* not compiled in!");
1046                         ret = -EINVAL;
1047                         goto out;
1048 #endif
1049                 case Opt_fatal_errors:
1050                         if (strcmp(args[0].from, "panic") == 0) {
1051                                 btrfs_set_opt(info->mount_opt,
1052                                               PANIC_ON_FATAL_ERROR);
1053                         } else if (strcmp(args[0].from, "bug") == 0) {
1054                                 btrfs_clear_opt(info->mount_opt,
1055                                               PANIC_ON_FATAL_ERROR);
1056                         } else {
1057                                 btrfs_err(info, "unrecognized fatal_errors value %s",
1058                                           args[0].from);
1059                                 ret = -EINVAL;
1060                                 goto out;
1061                         }
1062                         break;
1063                 case Opt_commit_interval:
1064                         intarg = 0;
1065                         ret = match_int(&args[0], &intarg);
1066                         if (ret) {
1067                                 btrfs_err(info, "unrecognized commit_interval value %s",
1068                                           args[0].from);
1069                                 ret = -EINVAL;
1070                                 goto out;
1071                         }
1072                         if (intarg == 0) {
1073                                 btrfs_info(info,
1074                                            "using default commit interval %us",
1075                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
1076                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
1077                         } else if (intarg > 300) {
1078                                 btrfs_warn(info, "excessive commit interval %d",
1079                                            intarg);
1080                         }
1081                         info->commit_interval = intarg;
1082                         break;
1083                 case Opt_rescue:
1084                         ret = parse_rescue_options(info, args[0].from);
1085                         if (ret < 0) {
1086                                 btrfs_err(info, "unrecognized rescue value %s",
1087                                           args[0].from);
1088                                 goto out;
1089                         }
1090                         break;
1091 #ifdef CONFIG_BTRFS_DEBUG
1092                 case Opt_fragment_all:
1093                         btrfs_info(info, "fragmenting all space");
1094                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
1095                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
1096                         break;
1097                 case Opt_fragment_metadata:
1098                         btrfs_info(info, "fragmenting metadata");
1099                         btrfs_set_opt(info->mount_opt,
1100                                       FRAGMENT_METADATA);
1101                         break;
1102                 case Opt_fragment_data:
1103                         btrfs_info(info, "fragmenting data");
1104                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
1105                         break;
1106 #endif
1107 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
1108                 case Opt_ref_verify:
1109                         btrfs_info(info, "doing ref verification");
1110                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
1111                         break;
1112 #endif
1113                 case Opt_err:
1114                         btrfs_err(info, "unrecognized mount option '%s'", p);
1115                         ret = -EINVAL;
1116                         goto out;
1117                 default:
1118                         break;
1119                 }
1120         }
1121 check:
1122         /* We're read-only, don't have to check. */
1123         if (new_flags & SB_RDONLY)
1124                 goto out;
1125
1126         if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
1127             check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
1128             check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))
1129                 ret = -EINVAL;
1130 out:
1131         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
1132             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
1133             !btrfs_test_opt(info, CLEAR_CACHE)) {
1134                 btrfs_err(info, "cannot disable free space tree");
1135                 ret = -EINVAL;
1136
1137         }
1138         if (!ret)
1139                 ret = btrfs_check_mountopts_zoned(info);
1140         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
1141                 btrfs_info(info, "disk space caching is enabled");
1142         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
1143                 btrfs_info(info, "using free space tree");
1144         return ret;
1145 }
1146
1147 /*
1148  * Parse mount options that are required early in the mount process.
1149  *
1150  * All other options will be parsed on much later in the mount process and
1151  * only when we need to allocate a new super block.
1152  */
1153 static int btrfs_parse_device_options(const char *options, fmode_t flags,
1154                                       void *holder)
1155 {
1156         substring_t args[MAX_OPT_ARGS];
1157         char *device_name, *opts, *orig, *p;
1158         struct btrfs_device *device = NULL;
1159         int error = 0;
1160
1161         lockdep_assert_held(&uuid_mutex);
1162
1163         if (!options)
1164                 return 0;
1165
1166         /*
1167          * strsep changes the string, duplicate it because btrfs_parse_options
1168          * gets called later
1169          */
1170         opts = kstrdup(options, GFP_KERNEL);
1171         if (!opts)
1172                 return -ENOMEM;
1173         orig = opts;
1174
1175         while ((p = strsep(&opts, ",")) != NULL) {
1176                 int token;
1177
1178                 if (!*p)
1179                         continue;
1180
1181                 token = match_token(p, tokens, args);
1182                 if (token == Opt_device) {
1183                         device_name = match_strdup(&args[0]);
1184                         if (!device_name) {
1185                                 error = -ENOMEM;
1186                                 goto out;
1187                         }
1188                         device = btrfs_scan_one_device(device_name, flags,
1189                                         holder);
1190                         kfree(device_name);
1191                         if (IS_ERR(device)) {
1192                                 error = PTR_ERR(device);
1193                                 goto out;
1194                         }
1195                 }
1196         }
1197
1198 out:
1199         kfree(orig);
1200         return error;
1201 }
1202
1203 /*
1204  * Parse mount options that are related to subvolume id
1205  *
1206  * The value is later passed to mount_subvol()
1207  */
1208 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
1209                 u64 *subvol_objectid)
1210 {
1211         substring_t args[MAX_OPT_ARGS];
1212         char *opts, *orig, *p;
1213         int error = 0;
1214         u64 subvolid;
1215
1216         if (!options)
1217                 return 0;
1218
1219         /*
1220          * strsep changes the string, duplicate it because
1221          * btrfs_parse_device_options gets called later
1222          */
1223         opts = kstrdup(options, GFP_KERNEL);
1224         if (!opts)
1225                 return -ENOMEM;
1226         orig = opts;
1227
1228         while ((p = strsep(&opts, ",")) != NULL) {
1229                 int token;
1230                 if (!*p)
1231                         continue;
1232
1233                 token = match_token(p, tokens, args);
1234                 switch (token) {
1235                 case Opt_subvol:
1236                         kfree(*subvol_name);
1237                         *subvol_name = match_strdup(&args[0]);
1238                         if (!*subvol_name) {
1239                                 error = -ENOMEM;
1240                                 goto out;
1241                         }
1242                         break;
1243                 case Opt_subvolid:
1244                         error = match_u64(&args[0], &subvolid);
1245                         if (error)
1246                                 goto out;
1247
1248                         /* we want the original fs_tree */
1249                         if (subvolid == 0)
1250                                 subvolid = BTRFS_FS_TREE_OBJECTID;
1251
1252                         *subvol_objectid = subvolid;
1253                         break;
1254                 default:
1255                         break;
1256                 }
1257         }
1258
1259 out:
1260         kfree(orig);
1261         return error;
1262 }
1263
1264 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
1265                                           u64 subvol_objectid)
1266 {
1267         struct btrfs_root *root = fs_info->tree_root;
1268         struct btrfs_root *fs_root = NULL;
1269         struct btrfs_root_ref *root_ref;
1270         struct btrfs_inode_ref *inode_ref;
1271         struct btrfs_key key;
1272         struct btrfs_path *path = NULL;
1273         char *name = NULL, *ptr;
1274         u64 dirid;
1275         int len;
1276         int ret;
1277
1278         path = btrfs_alloc_path();
1279         if (!path) {
1280                 ret = -ENOMEM;
1281                 goto err;
1282         }
1283
1284         name = kmalloc(PATH_MAX, GFP_KERNEL);
1285         if (!name) {
1286                 ret = -ENOMEM;
1287                 goto err;
1288         }
1289         ptr = name + PATH_MAX - 1;
1290         ptr[0] = '\0';
1291
1292         /*
1293          * Walk up the subvolume trees in the tree of tree roots by root
1294          * backrefs until we hit the top-level subvolume.
1295          */
1296         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1297                 key.objectid = subvol_objectid;
1298                 key.type = BTRFS_ROOT_BACKREF_KEY;
1299                 key.offset = (u64)-1;
1300
1301                 ret = btrfs_search_backwards(root, &key, path);
1302                 if (ret < 0) {
1303                         goto err;
1304                 } else if (ret > 0) {
1305                         ret = -ENOENT;
1306                         goto err;
1307                 }
1308
1309                 subvol_objectid = key.offset;
1310
1311                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1312                                           struct btrfs_root_ref);
1313                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1314                 ptr -= len + 1;
1315                 if (ptr < name) {
1316                         ret = -ENAMETOOLONG;
1317                         goto err;
1318                 }
1319                 read_extent_buffer(path->nodes[0], ptr + 1,
1320                                    (unsigned long)(root_ref + 1), len);
1321                 ptr[0] = '/';
1322                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1323                 btrfs_release_path(path);
1324
1325                 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
1326                 if (IS_ERR(fs_root)) {
1327                         ret = PTR_ERR(fs_root);
1328                         fs_root = NULL;
1329                         goto err;
1330                 }
1331
1332                 /*
1333                  * Walk up the filesystem tree by inode refs until we hit the
1334                  * root directory.
1335                  */
1336                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1337                         key.objectid = dirid;
1338                         key.type = BTRFS_INODE_REF_KEY;
1339                         key.offset = (u64)-1;
1340
1341                         ret = btrfs_search_backwards(fs_root, &key, path);
1342                         if (ret < 0) {
1343                                 goto err;
1344                         } else if (ret > 0) {
1345                                 ret = -ENOENT;
1346                                 goto err;
1347                         }
1348
1349                         dirid = key.offset;
1350
1351                         inode_ref = btrfs_item_ptr(path->nodes[0],
1352                                                    path->slots[0],
1353                                                    struct btrfs_inode_ref);
1354                         len = btrfs_inode_ref_name_len(path->nodes[0],
1355                                                        inode_ref);
1356                         ptr -= len + 1;
1357                         if (ptr < name) {
1358                                 ret = -ENAMETOOLONG;
1359                                 goto err;
1360                         }
1361                         read_extent_buffer(path->nodes[0], ptr + 1,
1362                                            (unsigned long)(inode_ref + 1), len);
1363                         ptr[0] = '/';
1364                         btrfs_release_path(path);
1365                 }
1366                 btrfs_put_root(fs_root);
1367                 fs_root = NULL;
1368         }
1369
1370         btrfs_free_path(path);
1371         if (ptr == name + PATH_MAX - 1) {
1372                 name[0] = '/';
1373                 name[1] = '\0';
1374         } else {
1375                 memmove(name, ptr, name + PATH_MAX - ptr);
1376         }
1377         return name;
1378
1379 err:
1380         btrfs_put_root(fs_root);
1381         btrfs_free_path(path);
1382         kfree(name);
1383         return ERR_PTR(ret);
1384 }
1385
1386 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1387 {
1388         struct btrfs_root *root = fs_info->tree_root;
1389         struct btrfs_dir_item *di;
1390         struct btrfs_path *path;
1391         struct btrfs_key location;
1392         u64 dir_id;
1393
1394         path = btrfs_alloc_path();
1395         if (!path)
1396                 return -ENOMEM;
1397
1398         /*
1399          * Find the "default" dir item which points to the root item that we
1400          * will mount by default if we haven't been given a specific subvolume
1401          * to mount.
1402          */
1403         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1404         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1405         if (IS_ERR(di)) {
1406                 btrfs_free_path(path);
1407                 return PTR_ERR(di);
1408         }
1409         if (!di) {
1410                 /*
1411                  * Ok the default dir item isn't there.  This is weird since
1412                  * it's always been there, but don't freak out, just try and
1413                  * mount the top-level subvolume.
1414                  */
1415                 btrfs_free_path(path);
1416                 *objectid = BTRFS_FS_TREE_OBJECTID;
1417                 return 0;
1418         }
1419
1420         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1421         btrfs_free_path(path);
1422         *objectid = location.objectid;
1423         return 0;
1424 }
1425
1426 static int btrfs_fill_super(struct super_block *sb,
1427                             struct btrfs_fs_devices *fs_devices,
1428                             void *data)
1429 {
1430         struct inode *inode;
1431         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1432         int err;
1433
1434         sb->s_maxbytes = MAX_LFS_FILESIZE;
1435         sb->s_magic = BTRFS_SUPER_MAGIC;
1436         sb->s_op = &btrfs_super_ops;
1437         sb->s_d_op = &btrfs_dentry_operations;
1438         sb->s_export_op = &btrfs_export_ops;
1439 #ifdef CONFIG_FS_VERITY
1440         sb->s_vop = &btrfs_verityops;
1441 #endif
1442         sb->s_xattr = btrfs_xattr_handlers;
1443         sb->s_time_gran = 1;
1444 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1445         sb->s_flags |= SB_POSIXACL;
1446 #endif
1447         sb->s_flags |= SB_I_VERSION;
1448         sb->s_iflags |= SB_I_CGROUPWB;
1449
1450         err = super_setup_bdi(sb);
1451         if (err) {
1452                 btrfs_err(fs_info, "super_setup_bdi failed");
1453                 return err;
1454         }
1455
1456         err = open_ctree(sb, fs_devices, (char *)data);
1457         if (err) {
1458                 btrfs_err(fs_info, "open_ctree failed");
1459                 return err;
1460         }
1461
1462         inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1463         if (IS_ERR(inode)) {
1464                 err = PTR_ERR(inode);
1465                 goto fail_close;
1466         }
1467
1468         sb->s_root = d_make_root(inode);
1469         if (!sb->s_root) {
1470                 err = -ENOMEM;
1471                 goto fail_close;
1472         }
1473
1474         sb->s_flags |= SB_ACTIVE;
1475         return 0;
1476
1477 fail_close:
1478         close_ctree(fs_info);
1479         return err;
1480 }
1481
1482 int btrfs_sync_fs(struct super_block *sb, int wait)
1483 {
1484         struct btrfs_trans_handle *trans;
1485         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1486         struct btrfs_root *root = fs_info->tree_root;
1487
1488         trace_btrfs_sync_fs(fs_info, wait);
1489
1490         if (!wait) {
1491                 filemap_flush(fs_info->btree_inode->i_mapping);
1492                 return 0;
1493         }
1494
1495         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1496
1497         trans = btrfs_attach_transaction_barrier(root);
1498         if (IS_ERR(trans)) {
1499                 /* no transaction, don't bother */
1500                 if (PTR_ERR(trans) == -ENOENT) {
1501                         /*
1502                          * Exit unless we have some pending changes
1503                          * that need to go through commit
1504                          */
1505                         if (fs_info->pending_changes == 0)
1506                                 return 0;
1507                         /*
1508                          * A non-blocking test if the fs is frozen. We must not
1509                          * start a new transaction here otherwise a deadlock
1510                          * happens. The pending operations are delayed to the
1511                          * next commit after thawing.
1512                          */
1513                         if (sb_start_write_trylock(sb))
1514                                 sb_end_write(sb);
1515                         else
1516                                 return 0;
1517                         trans = btrfs_start_transaction(root, 0);
1518                 }
1519                 if (IS_ERR(trans))
1520                         return PTR_ERR(trans);
1521         }
1522         return btrfs_commit_transaction(trans);
1523 }
1524
1525 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1526 {
1527         seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1528         *printed = true;
1529 }
1530
1531 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1532 {
1533         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1534         const char *compress_type;
1535         const char *subvol_name;
1536         bool printed = false;
1537
1538         if (btrfs_test_opt(info, DEGRADED))
1539                 seq_puts(seq, ",degraded");
1540         if (btrfs_test_opt(info, NODATASUM))
1541                 seq_puts(seq, ",nodatasum");
1542         if (btrfs_test_opt(info, NODATACOW))
1543                 seq_puts(seq, ",nodatacow");
1544         if (btrfs_test_opt(info, NOBARRIER))
1545                 seq_puts(seq, ",nobarrier");
1546         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1547                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1548         if (info->thread_pool_size !=  min_t(unsigned long,
1549                                              num_online_cpus() + 2, 8))
1550                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1551         if (btrfs_test_opt(info, COMPRESS)) {
1552                 compress_type = btrfs_compress_type2str(info->compress_type);
1553                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1554                         seq_printf(seq, ",compress-force=%s", compress_type);
1555                 else
1556                         seq_printf(seq, ",compress=%s", compress_type);
1557                 if (info->compress_level)
1558                         seq_printf(seq, ":%d", info->compress_level);
1559         }
1560         if (btrfs_test_opt(info, NOSSD))
1561                 seq_puts(seq, ",nossd");
1562         if (btrfs_test_opt(info, SSD_SPREAD))
1563                 seq_puts(seq, ",ssd_spread");
1564         else if (btrfs_test_opt(info, SSD))
1565                 seq_puts(seq, ",ssd");
1566         if (btrfs_test_opt(info, NOTREELOG))
1567                 seq_puts(seq, ",notreelog");
1568         if (btrfs_test_opt(info, NOLOGREPLAY))
1569                 print_rescue_option(seq, "nologreplay", &printed);
1570         if (btrfs_test_opt(info, USEBACKUPROOT))
1571                 print_rescue_option(seq, "usebackuproot", &printed);
1572         if (btrfs_test_opt(info, IGNOREBADROOTS))
1573                 print_rescue_option(seq, "ignorebadroots", &printed);
1574         if (btrfs_test_opt(info, IGNOREDATACSUMS))
1575                 print_rescue_option(seq, "ignoredatacsums", &printed);
1576         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1577                 seq_puts(seq, ",flushoncommit");
1578         if (btrfs_test_opt(info, DISCARD_SYNC))
1579                 seq_puts(seq, ",discard");
1580         if (btrfs_test_opt(info, DISCARD_ASYNC))
1581                 seq_puts(seq, ",discard=async");
1582         if (!(info->sb->s_flags & SB_POSIXACL))
1583                 seq_puts(seq, ",noacl");
1584         if (btrfs_free_space_cache_v1_active(info))
1585                 seq_puts(seq, ",space_cache");
1586         else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1587                 seq_puts(seq, ",space_cache=v2");
1588         else
1589                 seq_puts(seq, ",nospace_cache");
1590         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1591                 seq_puts(seq, ",rescan_uuid_tree");
1592         if (btrfs_test_opt(info, CLEAR_CACHE))
1593                 seq_puts(seq, ",clear_cache");
1594         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1595                 seq_puts(seq, ",user_subvol_rm_allowed");
1596         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1597                 seq_puts(seq, ",enospc_debug");
1598         if (btrfs_test_opt(info, AUTO_DEFRAG))
1599                 seq_puts(seq, ",autodefrag");
1600         if (btrfs_test_opt(info, SKIP_BALANCE))
1601                 seq_puts(seq, ",skip_balance");
1602 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1603         if (btrfs_test_opt(info, CHECK_INTEGRITY_DATA))
1604                 seq_puts(seq, ",check_int_data");
1605         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1606                 seq_puts(seq, ",check_int");
1607         if (info->check_integrity_print_mask)
1608                 seq_printf(seq, ",check_int_print_mask=%d",
1609                                 info->check_integrity_print_mask);
1610 #endif
1611         if (info->metadata_ratio)
1612                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1613         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1614                 seq_puts(seq, ",fatal_errors=panic");
1615         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1616                 seq_printf(seq, ",commit=%u", info->commit_interval);
1617 #ifdef CONFIG_BTRFS_DEBUG
1618         if (btrfs_test_opt(info, FRAGMENT_DATA))
1619                 seq_puts(seq, ",fragment=data");
1620         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1621                 seq_puts(seq, ",fragment=metadata");
1622 #endif
1623         if (btrfs_test_opt(info, REF_VERIFY))
1624                 seq_puts(seq, ",ref_verify");
1625         seq_printf(seq, ",subvolid=%llu",
1626                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1627         subvol_name = btrfs_get_subvol_name_from_objectid(info,
1628                         BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1629         if (!IS_ERR(subvol_name)) {
1630                 seq_puts(seq, ",subvol=");
1631                 seq_escape(seq, subvol_name, " \t\n\\");
1632                 kfree(subvol_name);
1633         }
1634         return 0;
1635 }
1636
1637 static int btrfs_test_super(struct super_block *s, void *data)
1638 {
1639         struct btrfs_fs_info *p = data;
1640         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1641
1642         return fs_info->fs_devices == p->fs_devices;
1643 }
1644
1645 static int btrfs_set_super(struct super_block *s, void *data)
1646 {
1647         int err = set_anon_super(s, data);
1648         if (!err)
1649                 s->s_fs_info = data;
1650         return err;
1651 }
1652
1653 /*
1654  * subvolumes are identified by ino 256
1655  */
1656 static inline int is_subvolume_inode(struct inode *inode)
1657 {
1658         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1659                 return 1;
1660         return 0;
1661 }
1662
1663 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1664                                    struct vfsmount *mnt)
1665 {
1666         struct dentry *root;
1667         int ret;
1668
1669         if (!subvol_name) {
1670                 if (!subvol_objectid) {
1671                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1672                                                           &subvol_objectid);
1673                         if (ret) {
1674                                 root = ERR_PTR(ret);
1675                                 goto out;
1676                         }
1677                 }
1678                 subvol_name = btrfs_get_subvol_name_from_objectid(
1679                                         btrfs_sb(mnt->mnt_sb), subvol_objectid);
1680                 if (IS_ERR(subvol_name)) {
1681                         root = ERR_CAST(subvol_name);
1682                         subvol_name = NULL;
1683                         goto out;
1684                 }
1685
1686         }
1687
1688         root = mount_subtree(mnt, subvol_name);
1689         /* mount_subtree() drops our reference on the vfsmount. */
1690         mnt = NULL;
1691
1692         if (!IS_ERR(root)) {
1693                 struct super_block *s = root->d_sb;
1694                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1695                 struct inode *root_inode = d_inode(root);
1696                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1697
1698                 ret = 0;
1699                 if (!is_subvolume_inode(root_inode)) {
1700                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1701                                subvol_name);
1702                         ret = -EINVAL;
1703                 }
1704                 if (subvol_objectid && root_objectid != subvol_objectid) {
1705                         /*
1706                          * This will also catch a race condition where a
1707                          * subvolume which was passed by ID is renamed and
1708                          * another subvolume is renamed over the old location.
1709                          */
1710                         btrfs_err(fs_info,
1711                                   "subvol '%s' does not match subvolid %llu",
1712                                   subvol_name, subvol_objectid);
1713                         ret = -EINVAL;
1714                 }
1715                 if (ret) {
1716                         dput(root);
1717                         root = ERR_PTR(ret);
1718                         deactivate_locked_super(s);
1719                 }
1720         }
1721
1722 out:
1723         mntput(mnt);
1724         kfree(subvol_name);
1725         return root;
1726 }
1727
1728 /*
1729  * Find a superblock for the given device / mount point.
1730  *
1731  * Note: This is based on mount_bdev from fs/super.c with a few additions
1732  *       for multiple device setup.  Make sure to keep it in sync.
1733  */
1734 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1735                 int flags, const char *device_name, void *data)
1736 {
1737         struct block_device *bdev = NULL;
1738         struct super_block *s;
1739         struct btrfs_device *device = NULL;
1740         struct btrfs_fs_devices *fs_devices = NULL;
1741         struct btrfs_fs_info *fs_info = NULL;
1742         void *new_sec_opts = NULL;
1743         fmode_t mode = FMODE_READ;
1744         int error = 0;
1745
1746         if (!(flags & SB_RDONLY))
1747                 mode |= FMODE_WRITE;
1748
1749         if (data) {
1750                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1751                 if (error)
1752                         return ERR_PTR(error);
1753         }
1754
1755         /*
1756          * Setup a dummy root and fs_info for test/set super.  This is because
1757          * we don't actually fill this stuff out until open_ctree, but we need
1758          * then open_ctree will properly initialize the file system specific
1759          * settings later.  btrfs_init_fs_info initializes the static elements
1760          * of the fs_info (locks and such) to make cleanup easier if we find a
1761          * superblock with our given fs_devices later on at sget() time.
1762          */
1763         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1764         if (!fs_info) {
1765                 error = -ENOMEM;
1766                 goto error_sec_opts;
1767         }
1768         btrfs_init_fs_info(fs_info);
1769
1770         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1771         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1772         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1773                 error = -ENOMEM;
1774                 goto error_fs_info;
1775         }
1776
1777         mutex_lock(&uuid_mutex);
1778         error = btrfs_parse_device_options(data, mode, fs_type);
1779         if (error) {
1780                 mutex_unlock(&uuid_mutex);
1781                 goto error_fs_info;
1782         }
1783
1784         device = btrfs_scan_one_device(device_name, mode, fs_type);
1785         if (IS_ERR(device)) {
1786                 mutex_unlock(&uuid_mutex);
1787                 error = PTR_ERR(device);
1788                 goto error_fs_info;
1789         }
1790
1791         fs_devices = device->fs_devices;
1792         fs_info->fs_devices = fs_devices;
1793
1794         error = btrfs_open_devices(fs_devices, mode, fs_type);
1795         mutex_unlock(&uuid_mutex);
1796         if (error)
1797                 goto error_fs_info;
1798
1799         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1800                 error = -EACCES;
1801                 goto error_close_devices;
1802         }
1803
1804         bdev = fs_devices->latest_dev->bdev;
1805         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1806                  fs_info);
1807         if (IS_ERR(s)) {
1808                 error = PTR_ERR(s);
1809                 goto error_close_devices;
1810         }
1811
1812         if (s->s_root) {
1813                 btrfs_close_devices(fs_devices);
1814                 btrfs_free_fs_info(fs_info);
1815                 if ((flags ^ s->s_flags) & SB_RDONLY)
1816                         error = -EBUSY;
1817         } else {
1818                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1819                 shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name,
1820                                         s->s_id);
1821                 btrfs_sb(s)->bdev_holder = fs_type;
1822                 if (!strstr(crc32c_impl(), "generic"))
1823                         set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
1824                 error = btrfs_fill_super(s, fs_devices, data);
1825         }
1826         if (!error)
1827                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1828         security_free_mnt_opts(&new_sec_opts);
1829         if (error) {
1830                 deactivate_locked_super(s);
1831                 return ERR_PTR(error);
1832         }
1833
1834         return dget(s->s_root);
1835
1836 error_close_devices:
1837         btrfs_close_devices(fs_devices);
1838 error_fs_info:
1839         btrfs_free_fs_info(fs_info);
1840 error_sec_opts:
1841         security_free_mnt_opts(&new_sec_opts);
1842         return ERR_PTR(error);
1843 }
1844
1845 /*
1846  * Mount function which is called by VFS layer.
1847  *
1848  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1849  * which needs vfsmount* of device's root (/).  This means device's root has to
1850  * be mounted internally in any case.
1851  *
1852  * Operation flow:
1853  *   1. Parse subvol id related options for later use in mount_subvol().
1854  *
1855  *   2. Mount device's root (/) by calling vfs_kern_mount().
1856  *
1857  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1858  *      first place. In order to avoid calling btrfs_mount() again, we use
1859  *      different file_system_type which is not registered to VFS by
1860  *      register_filesystem() (btrfs_root_fs_type). As a result,
1861  *      btrfs_mount_root() is called. The return value will be used by
1862  *      mount_subtree() in mount_subvol().
1863  *
1864  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1865  *      "btrfs subvolume set-default", mount_subvol() is called always.
1866  */
1867 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1868                 const char *device_name, void *data)
1869 {
1870         struct vfsmount *mnt_root;
1871         struct dentry *root;
1872         char *subvol_name = NULL;
1873         u64 subvol_objectid = 0;
1874         int error = 0;
1875
1876         error = btrfs_parse_subvol_options(data, &subvol_name,
1877                                         &subvol_objectid);
1878         if (error) {
1879                 kfree(subvol_name);
1880                 return ERR_PTR(error);
1881         }
1882
1883         /* mount device's root (/) */
1884         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1885         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1886                 if (flags & SB_RDONLY) {
1887                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1888                                 flags & ~SB_RDONLY, device_name, data);
1889                 } else {
1890                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1891                                 flags | SB_RDONLY, device_name, data);
1892                         if (IS_ERR(mnt_root)) {
1893                                 root = ERR_CAST(mnt_root);
1894                                 kfree(subvol_name);
1895                                 goto out;
1896                         }
1897
1898                         down_write(&mnt_root->mnt_sb->s_umount);
1899                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1900                         up_write(&mnt_root->mnt_sb->s_umount);
1901                         if (error < 0) {
1902                                 root = ERR_PTR(error);
1903                                 mntput(mnt_root);
1904                                 kfree(subvol_name);
1905                                 goto out;
1906                         }
1907                 }
1908         }
1909         if (IS_ERR(mnt_root)) {
1910                 root = ERR_CAST(mnt_root);
1911                 kfree(subvol_name);
1912                 goto out;
1913         }
1914
1915         /* mount_subvol() will free subvol_name and mnt_root */
1916         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1917
1918 out:
1919         return root;
1920 }
1921
1922 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1923                                      u32 new_pool_size, u32 old_pool_size)
1924 {
1925         if (new_pool_size == old_pool_size)
1926                 return;
1927
1928         fs_info->thread_pool_size = new_pool_size;
1929
1930         btrfs_info(fs_info, "resize thread pool %d -> %d",
1931                old_pool_size, new_pool_size);
1932
1933         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1934         btrfs_workqueue_set_max(fs_info->hipri_workers, new_pool_size);
1935         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1936         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1937         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1938         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1939         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1940 }
1941
1942 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1943                                        unsigned long old_opts, int flags)
1944 {
1945         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1946             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1947              (flags & SB_RDONLY))) {
1948                 /* wait for any defraggers to finish */
1949                 wait_event(fs_info->transaction_wait,
1950                            (atomic_read(&fs_info->defrag_running) == 0));
1951                 if (flags & SB_RDONLY)
1952                         sync_filesystem(fs_info->sb);
1953         }
1954 }
1955
1956 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1957                                          unsigned long old_opts)
1958 {
1959         const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1960
1961         /*
1962          * We need to cleanup all defragable inodes if the autodefragment is
1963          * close or the filesystem is read only.
1964          */
1965         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1966             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1967                 btrfs_cleanup_defrag_inodes(fs_info);
1968         }
1969
1970         /* If we toggled discard async */
1971         if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1972             btrfs_test_opt(fs_info, DISCARD_ASYNC))
1973                 btrfs_discard_resume(fs_info);
1974         else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1975                  !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1976                 btrfs_discard_cleanup(fs_info);
1977
1978         /* If we toggled space cache */
1979         if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1980                 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1981 }
1982
1983 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1984 {
1985         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1986         unsigned old_flags = sb->s_flags;
1987         unsigned long old_opts = fs_info->mount_opt;
1988         unsigned long old_compress_type = fs_info->compress_type;
1989         u64 old_max_inline = fs_info->max_inline;
1990         u32 old_thread_pool_size = fs_info->thread_pool_size;
1991         u32 old_metadata_ratio = fs_info->metadata_ratio;
1992         int ret;
1993
1994         sync_filesystem(sb);
1995         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1996
1997         if (data) {
1998                 void *new_sec_opts = NULL;
1999
2000                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
2001                 if (!ret)
2002                         ret = security_sb_remount(sb, new_sec_opts);
2003                 security_free_mnt_opts(&new_sec_opts);
2004                 if (ret)
2005                         goto restore;
2006         }
2007
2008         ret = btrfs_parse_options(fs_info, data, *flags);
2009         if (ret)
2010                 goto restore;
2011
2012         /* V1 cache is not supported for subpage mount. */
2013         if (fs_info->sectorsize < PAGE_SIZE && btrfs_test_opt(fs_info, SPACE_CACHE)) {
2014                 btrfs_warn(fs_info,
2015         "v1 space cache is not supported for page size %lu with sectorsize %u",
2016                            PAGE_SIZE, fs_info->sectorsize);
2017                 ret = -EINVAL;
2018                 goto restore;
2019         }
2020         btrfs_remount_begin(fs_info, old_opts, *flags);
2021         btrfs_resize_thread_pool(fs_info,
2022                 fs_info->thread_pool_size, old_thread_pool_size);
2023
2024         if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
2025             (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
2026             (!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
2027                 btrfs_warn(fs_info,
2028                 "remount supports changing free space tree only from ro to rw");
2029                 /* Make sure free space cache options match the state on disk */
2030                 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
2031                         btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
2032                         btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
2033                 }
2034                 if (btrfs_free_space_cache_v1_active(fs_info)) {
2035                         btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
2036                         btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
2037                 }
2038         }
2039
2040         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
2041                 goto out;
2042
2043         if (*flags & SB_RDONLY) {
2044                 /*
2045                  * this also happens on 'umount -rf' or on shutdown, when
2046                  * the filesystem is busy.
2047                  */
2048                 cancel_work_sync(&fs_info->async_reclaim_work);
2049                 cancel_work_sync(&fs_info->async_data_reclaim_work);
2050
2051                 btrfs_discard_cleanup(fs_info);
2052
2053                 /* wait for the uuid_scan task to finish */
2054                 down(&fs_info->uuid_tree_rescan_sem);
2055                 /* avoid complains from lockdep et al. */
2056                 up(&fs_info->uuid_tree_rescan_sem);
2057
2058                 btrfs_set_sb_rdonly(sb);
2059
2060                 /*
2061                  * Setting SB_RDONLY will put the cleaner thread to
2062                  * sleep at the next loop if it's already active.
2063                  * If it's already asleep, we'll leave unused block
2064                  * groups on disk until we're mounted read-write again
2065                  * unless we clean them up here.
2066                  */
2067                 btrfs_delete_unused_bgs(fs_info);
2068
2069                 /*
2070                  * The cleaner task could be already running before we set the
2071                  * flag BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock).
2072                  * We must make sure that after we finish the remount, i.e. after
2073                  * we call btrfs_commit_super(), the cleaner can no longer start
2074                  * a transaction - either because it was dropping a dead root,
2075                  * running delayed iputs or deleting an unused block group (the
2076                  * cleaner picked a block group from the list of unused block
2077                  * groups before we were able to in the previous call to
2078                  * btrfs_delete_unused_bgs()).
2079                  */
2080                 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING,
2081                             TASK_UNINTERRUPTIBLE);
2082
2083                 /*
2084                  * We've set the superblock to RO mode, so we might have made
2085                  * the cleaner task sleep without running all pending delayed
2086                  * iputs. Go through all the delayed iputs here, so that if an
2087                  * unmount happens without remounting RW we don't end up at
2088                  * finishing close_ctree() with a non-empty list of delayed
2089                  * iputs.
2090                  */
2091                 btrfs_run_delayed_iputs(fs_info);
2092
2093                 btrfs_dev_replace_suspend_for_unmount(fs_info);
2094                 btrfs_scrub_cancel(fs_info);
2095                 btrfs_pause_balance(fs_info);
2096
2097                 /*
2098                  * Pause the qgroup rescan worker if it is running. We don't want
2099                  * it to be still running after we are in RO mode, as after that,
2100                  * by the time we unmount, it might have left a transaction open,
2101                  * so we would leak the transaction and/or crash.
2102                  */
2103                 btrfs_qgroup_wait_for_completion(fs_info, false);
2104
2105                 ret = btrfs_commit_super(fs_info);
2106                 if (ret)
2107                         goto restore;
2108         } else {
2109                 if (BTRFS_FS_ERROR(fs_info)) {
2110                         btrfs_err(fs_info,
2111                                 "Remounting read-write after error is not allowed");
2112                         ret = -EINVAL;
2113                         goto restore;
2114                 }
2115                 if (fs_info->fs_devices->rw_devices == 0) {
2116                         ret = -EACCES;
2117                         goto restore;
2118                 }
2119
2120                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
2121                         btrfs_warn(fs_info,
2122                 "too many missing devices, writable remount is not allowed");
2123                         ret = -EACCES;
2124                         goto restore;
2125                 }
2126
2127                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
2128                         btrfs_warn(fs_info,
2129                 "mount required to replay tree-log, cannot remount read-write");
2130                         ret = -EINVAL;
2131                         goto restore;
2132                 }
2133
2134                 /*
2135                  * NOTE: when remounting with a change that does writes, don't
2136                  * put it anywhere above this point, as we are not sure to be
2137                  * safe to write until we pass the above checks.
2138                  */
2139                 ret = btrfs_start_pre_rw_mount(fs_info);
2140                 if (ret)
2141                         goto restore;
2142
2143                 btrfs_clear_sb_rdonly(sb);
2144
2145                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
2146         }
2147 out:
2148         /*
2149          * We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
2150          * since the absence of the flag means it can be toggled off by remount.
2151          */
2152         *flags |= SB_I_VERSION;
2153
2154         wake_up_process(fs_info->transaction_kthread);
2155         btrfs_remount_cleanup(fs_info, old_opts);
2156         btrfs_clear_oneshot_options(fs_info);
2157         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
2158
2159         return 0;
2160
2161 restore:
2162         /* We've hit an error - don't reset SB_RDONLY */
2163         if (sb_rdonly(sb))
2164                 old_flags |= SB_RDONLY;
2165         if (!(old_flags & SB_RDONLY))
2166                 clear_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
2167         sb->s_flags = old_flags;
2168         fs_info->mount_opt = old_opts;
2169         fs_info->compress_type = old_compress_type;
2170         fs_info->max_inline = old_max_inline;
2171         btrfs_resize_thread_pool(fs_info,
2172                 old_thread_pool_size, fs_info->thread_pool_size);
2173         fs_info->metadata_ratio = old_metadata_ratio;
2174         btrfs_remount_cleanup(fs_info, old_opts);
2175         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
2176
2177         return ret;
2178 }
2179
2180 /* Used to sort the devices by max_avail(descending sort) */
2181 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
2182 {
2183         const struct btrfs_device_info *dev_info1 = a;
2184         const struct btrfs_device_info *dev_info2 = b;
2185
2186         if (dev_info1->max_avail > dev_info2->max_avail)
2187                 return -1;
2188         else if (dev_info1->max_avail < dev_info2->max_avail)
2189                 return 1;
2190         return 0;
2191 }
2192
2193 /*
2194  * sort the devices by max_avail, in which max free extent size of each device
2195  * is stored.(Descending Sort)
2196  */
2197 static inline void btrfs_descending_sort_devices(
2198                                         struct btrfs_device_info *devices,
2199                                         size_t nr_devices)
2200 {
2201         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
2202              btrfs_cmp_device_free_bytes, NULL);
2203 }
2204
2205 /*
2206  * The helper to calc the free space on the devices that can be used to store
2207  * file data.
2208  */
2209 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
2210                                               u64 *free_bytes)
2211 {
2212         struct btrfs_device_info *devices_info;
2213         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2214         struct btrfs_device *device;
2215         u64 type;
2216         u64 avail_space;
2217         u64 min_stripe_size;
2218         int num_stripes = 1;
2219         int i = 0, nr_devices;
2220         const struct btrfs_raid_attr *rattr;
2221
2222         /*
2223          * We aren't under the device list lock, so this is racy-ish, but good
2224          * enough for our purposes.
2225          */
2226         nr_devices = fs_info->fs_devices->open_devices;
2227         if (!nr_devices) {
2228                 smp_mb();
2229                 nr_devices = fs_info->fs_devices->open_devices;
2230                 ASSERT(nr_devices);
2231                 if (!nr_devices) {
2232                         *free_bytes = 0;
2233                         return 0;
2234                 }
2235         }
2236
2237         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
2238                                GFP_KERNEL);
2239         if (!devices_info)
2240                 return -ENOMEM;
2241
2242         /* calc min stripe number for data space allocation */
2243         type = btrfs_data_alloc_profile(fs_info);
2244         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
2245
2246         if (type & BTRFS_BLOCK_GROUP_RAID0)
2247                 num_stripes = nr_devices;
2248         else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
2249                 num_stripes = rattr->ncopies;
2250         else if (type & BTRFS_BLOCK_GROUP_RAID10)
2251                 num_stripes = 4;
2252
2253         /* Adjust for more than 1 stripe per device */
2254         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
2255
2256         rcu_read_lock();
2257         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
2258                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
2259                                                 &device->dev_state) ||
2260                     !device->bdev ||
2261                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
2262                         continue;
2263
2264                 if (i >= nr_devices)
2265                         break;
2266
2267                 avail_space = device->total_bytes - device->bytes_used;
2268
2269                 /* align with stripe_len */
2270                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
2271
2272                 /*
2273                  * Ensure we have at least min_stripe_size on top of the
2274                  * reserved space on the device.
2275                  */
2276                 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
2277                         continue;
2278
2279                 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
2280
2281                 devices_info[i].dev = device;
2282                 devices_info[i].max_avail = avail_space;
2283
2284                 i++;
2285         }
2286         rcu_read_unlock();
2287
2288         nr_devices = i;
2289
2290         btrfs_descending_sort_devices(devices_info, nr_devices);
2291
2292         i = nr_devices - 1;
2293         avail_space = 0;
2294         while (nr_devices >= rattr->devs_min) {
2295                 num_stripes = min(num_stripes, nr_devices);
2296
2297                 if (devices_info[i].max_avail >= min_stripe_size) {
2298                         int j;
2299                         u64 alloc_size;
2300
2301                         avail_space += devices_info[i].max_avail * num_stripes;
2302                         alloc_size = devices_info[i].max_avail;
2303                         for (j = i + 1 - num_stripes; j <= i; j++)
2304                                 devices_info[j].max_avail -= alloc_size;
2305                 }
2306                 i--;
2307                 nr_devices--;
2308         }
2309
2310         kfree(devices_info);
2311         *free_bytes = avail_space;
2312         return 0;
2313 }
2314
2315 /*
2316  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2317  *
2318  * If there's a redundant raid level at DATA block groups, use the respective
2319  * multiplier to scale the sizes.
2320  *
2321  * Unused device space usage is based on simulating the chunk allocator
2322  * algorithm that respects the device sizes and order of allocations.  This is
2323  * a close approximation of the actual use but there are other factors that may
2324  * change the result (like a new metadata chunk).
2325  *
2326  * If metadata is exhausted, f_bavail will be 0.
2327  */
2328 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2329 {
2330         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2331         struct btrfs_super_block *disk_super = fs_info->super_copy;
2332         struct btrfs_space_info *found;
2333         u64 total_used = 0;
2334         u64 total_free_data = 0;
2335         u64 total_free_meta = 0;
2336         u32 bits = fs_info->sectorsize_bits;
2337         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2338         unsigned factor = 1;
2339         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2340         int ret;
2341         u64 thresh = 0;
2342         int mixed = 0;
2343
2344         list_for_each_entry(found, &fs_info->space_info, list) {
2345                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2346                         int i;
2347
2348                         total_free_data += found->disk_total - found->disk_used;
2349                         total_free_data -=
2350                                 btrfs_account_ro_block_groups_free_space(found);
2351
2352                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2353                                 if (!list_empty(&found->block_groups[i]))
2354                                         factor = btrfs_bg_type_to_factor(
2355                                                 btrfs_raid_array[i].bg_flag);
2356                         }
2357                 }
2358
2359                 /*
2360                  * Metadata in mixed block goup profiles are accounted in data
2361                  */
2362                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2363                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2364                                 mixed = 1;
2365                         else
2366                                 total_free_meta += found->disk_total -
2367                                         found->disk_used;
2368                 }
2369
2370                 total_used += found->disk_used;
2371         }
2372
2373         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2374         buf->f_blocks >>= bits;
2375         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2376
2377         /* Account global block reserve as used, it's in logical size already */
2378         spin_lock(&block_rsv->lock);
2379         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2380         if (buf->f_bfree >= block_rsv->size >> bits)
2381                 buf->f_bfree -= block_rsv->size >> bits;
2382         else
2383                 buf->f_bfree = 0;
2384         spin_unlock(&block_rsv->lock);
2385
2386         buf->f_bavail = div_u64(total_free_data, factor);
2387         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2388         if (ret)
2389                 return ret;
2390         buf->f_bavail += div_u64(total_free_data, factor);
2391         buf->f_bavail = buf->f_bavail >> bits;
2392
2393         /*
2394          * We calculate the remaining metadata space minus global reserve. If
2395          * this is (supposedly) smaller than zero, there's no space. But this
2396          * does not hold in practice, the exhausted state happens where's still
2397          * some positive delta. So we apply some guesswork and compare the
2398          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2399          *
2400          * We probably cannot calculate the exact threshold value because this
2401          * depends on the internal reservations requested by various
2402          * operations, so some operations that consume a few metadata will
2403          * succeed even if the Avail is zero. But this is better than the other
2404          * way around.
2405          */
2406         thresh = SZ_4M;
2407
2408         /*
2409          * We only want to claim there's no available space if we can no longer
2410          * allocate chunks for our metadata profile and our global reserve will
2411          * not fit in the free metadata space.  If we aren't ->full then we
2412          * still can allocate chunks and thus are fine using the currently
2413          * calculated f_bavail.
2414          */
2415         if (!mixed && block_rsv->space_info->full &&
2416             total_free_meta - thresh < block_rsv->size)
2417                 buf->f_bavail = 0;
2418
2419         buf->f_type = BTRFS_SUPER_MAGIC;
2420         buf->f_bsize = dentry->d_sb->s_blocksize;
2421         buf->f_namelen = BTRFS_NAME_LEN;
2422
2423         /* We treat it as constant endianness (it doesn't matter _which_)
2424            because we want the fsid to come out the same whether mounted
2425            on a big-endian or little-endian host */
2426         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2427         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2428         /* Mask in the root object ID too, to disambiguate subvols */
2429         buf->f_fsid.val[0] ^=
2430                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2431         buf->f_fsid.val[1] ^=
2432                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2433
2434         return 0;
2435 }
2436
2437 static void btrfs_kill_super(struct super_block *sb)
2438 {
2439         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2440         kill_anon_super(sb);
2441         btrfs_free_fs_info(fs_info);
2442 }
2443
2444 static struct file_system_type btrfs_fs_type = {
2445         .owner          = THIS_MODULE,
2446         .name           = "btrfs",
2447         .mount          = btrfs_mount,
2448         .kill_sb        = btrfs_kill_super,
2449         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2450 };
2451
2452 static struct file_system_type btrfs_root_fs_type = {
2453         .owner          = THIS_MODULE,
2454         .name           = "btrfs",
2455         .mount          = btrfs_mount_root,
2456         .kill_sb        = btrfs_kill_super,
2457         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2458 };
2459
2460 MODULE_ALIAS_FS("btrfs");
2461
2462 static int btrfs_control_open(struct inode *inode, struct file *file)
2463 {
2464         /*
2465          * The control file's private_data is used to hold the
2466          * transaction when it is started and is used to keep
2467          * track of whether a transaction is already in progress.
2468          */
2469         file->private_data = NULL;
2470         return 0;
2471 }
2472
2473 /*
2474  * Used by /dev/btrfs-control for devices ioctls.
2475  */
2476 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2477                                 unsigned long arg)
2478 {
2479         struct btrfs_ioctl_vol_args *vol;
2480         struct btrfs_device *device = NULL;
2481         dev_t devt = 0;
2482         int ret = -ENOTTY;
2483
2484         if (!capable(CAP_SYS_ADMIN))
2485                 return -EPERM;
2486
2487         vol = memdup_user((void __user *)arg, sizeof(*vol));
2488         if (IS_ERR(vol))
2489                 return PTR_ERR(vol);
2490         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2491
2492         switch (cmd) {
2493         case BTRFS_IOC_SCAN_DEV:
2494                 mutex_lock(&uuid_mutex);
2495                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2496                                                &btrfs_root_fs_type);
2497                 ret = PTR_ERR_OR_ZERO(device);
2498                 mutex_unlock(&uuid_mutex);
2499                 break;
2500         case BTRFS_IOC_FORGET_DEV:
2501                 if (vol->name[0] != 0) {
2502                         ret = lookup_bdev(vol->name, &devt);
2503                         if (ret)
2504                                 break;
2505                 }
2506                 ret = btrfs_forget_devices(devt);
2507                 break;
2508         case BTRFS_IOC_DEVICES_READY:
2509                 mutex_lock(&uuid_mutex);
2510                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2511                                                &btrfs_root_fs_type);
2512                 if (IS_ERR(device)) {
2513                         mutex_unlock(&uuid_mutex);
2514                         ret = PTR_ERR(device);
2515                         break;
2516                 }
2517                 ret = !(device->fs_devices->num_devices ==
2518                         device->fs_devices->total_devices);
2519                 mutex_unlock(&uuid_mutex);
2520                 break;
2521         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2522                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2523                 break;
2524         }
2525
2526         kfree(vol);
2527         return ret;
2528 }
2529
2530 static int btrfs_freeze(struct super_block *sb)
2531 {
2532         struct btrfs_trans_handle *trans;
2533         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2534         struct btrfs_root *root = fs_info->tree_root;
2535
2536         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2537         /*
2538          * We don't need a barrier here, we'll wait for any transaction that
2539          * could be in progress on other threads (and do delayed iputs that
2540          * we want to avoid on a frozen filesystem), or do the commit
2541          * ourselves.
2542          */
2543         trans = btrfs_attach_transaction_barrier(root);
2544         if (IS_ERR(trans)) {
2545                 /* no transaction, don't bother */
2546                 if (PTR_ERR(trans) == -ENOENT)
2547                         return 0;
2548                 return PTR_ERR(trans);
2549         }
2550         return btrfs_commit_transaction(trans);
2551 }
2552
2553 static int btrfs_unfreeze(struct super_block *sb)
2554 {
2555         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2556
2557         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2558         return 0;
2559 }
2560
2561 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2562 {
2563         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2564
2565         /*
2566          * There should be always a valid pointer in latest_dev, it may be stale
2567          * for a short moment in case it's being deleted but still valid until
2568          * the end of RCU grace period.
2569          */
2570         rcu_read_lock();
2571         seq_escape(m, rcu_str_deref(fs_info->fs_devices->latest_dev->name), " \t\n\\");
2572         rcu_read_unlock();
2573
2574         return 0;
2575 }
2576
2577 static const struct super_operations btrfs_super_ops = {
2578         .drop_inode     = btrfs_drop_inode,
2579         .evict_inode    = btrfs_evict_inode,
2580         .put_super      = btrfs_put_super,
2581         .sync_fs        = btrfs_sync_fs,
2582         .show_options   = btrfs_show_options,
2583         .show_devname   = btrfs_show_devname,
2584         .alloc_inode    = btrfs_alloc_inode,
2585         .destroy_inode  = btrfs_destroy_inode,
2586         .free_inode     = btrfs_free_inode,
2587         .statfs         = btrfs_statfs,
2588         .remount_fs     = btrfs_remount,
2589         .freeze_fs      = btrfs_freeze,
2590         .unfreeze_fs    = btrfs_unfreeze,
2591 };
2592
2593 static const struct file_operations btrfs_ctl_fops = {
2594         .open = btrfs_control_open,
2595         .unlocked_ioctl  = btrfs_control_ioctl,
2596         .compat_ioctl = compat_ptr_ioctl,
2597         .owner   = THIS_MODULE,
2598         .llseek = noop_llseek,
2599 };
2600
2601 static struct miscdevice btrfs_misc = {
2602         .minor          = BTRFS_MINOR,
2603         .name           = "btrfs-control",
2604         .fops           = &btrfs_ctl_fops
2605 };
2606
2607 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2608 MODULE_ALIAS("devname:btrfs-control");
2609
2610 static int __init btrfs_interface_init(void)
2611 {
2612         return misc_register(&btrfs_misc);
2613 }
2614
2615 static __cold void btrfs_interface_exit(void)
2616 {
2617         misc_deregister(&btrfs_misc);
2618 }
2619
2620 static void __init btrfs_print_mod_info(void)
2621 {
2622         static const char options[] = ""
2623 #ifdef CONFIG_BTRFS_DEBUG
2624                         ", debug=on"
2625 #endif
2626 #ifdef CONFIG_BTRFS_ASSERT
2627                         ", assert=on"
2628 #endif
2629 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2630                         ", integrity-checker=on"
2631 #endif
2632 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2633                         ", ref-verify=on"
2634 #endif
2635 #ifdef CONFIG_BLK_DEV_ZONED
2636                         ", zoned=yes"
2637 #else
2638                         ", zoned=no"
2639 #endif
2640 #ifdef CONFIG_FS_VERITY
2641                         ", fsverity=yes"
2642 #else
2643                         ", fsverity=no"
2644 #endif
2645                         ;
2646         pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
2647 }
2648
2649 static int __init init_btrfs_fs(void)
2650 {
2651         int err;
2652
2653         btrfs_props_init();
2654
2655         err = btrfs_init_sysfs();
2656         if (err)
2657                 return err;
2658
2659         btrfs_init_compress();
2660
2661         err = btrfs_init_cachep();
2662         if (err)
2663                 goto free_compress;
2664
2665         err = extent_io_init();
2666         if (err)
2667                 goto free_cachep;
2668
2669         err = extent_state_cache_init();
2670         if (err)
2671                 goto free_extent_io;
2672
2673         err = extent_map_init();
2674         if (err)
2675                 goto free_extent_state_cache;
2676
2677         err = ordered_data_init();
2678         if (err)
2679                 goto free_extent_map;
2680
2681         err = btrfs_delayed_inode_init();
2682         if (err)
2683                 goto free_ordered_data;
2684
2685         err = btrfs_auto_defrag_init();
2686         if (err)
2687                 goto free_delayed_inode;
2688
2689         err = btrfs_delayed_ref_init();
2690         if (err)
2691                 goto free_auto_defrag;
2692
2693         err = btrfs_prelim_ref_init();
2694         if (err)
2695                 goto free_delayed_ref;
2696
2697         err = btrfs_interface_init();
2698         if (err)
2699                 goto free_prelim_ref;
2700
2701         btrfs_print_mod_info();
2702
2703         err = btrfs_run_sanity_tests();
2704         if (err)
2705                 goto unregister_ioctl;
2706
2707         err = register_filesystem(&btrfs_fs_type);
2708         if (err)
2709                 goto unregister_ioctl;
2710
2711         return 0;
2712
2713 unregister_ioctl:
2714         btrfs_interface_exit();
2715 free_prelim_ref:
2716         btrfs_prelim_ref_exit();
2717 free_delayed_ref:
2718         btrfs_delayed_ref_exit();
2719 free_auto_defrag:
2720         btrfs_auto_defrag_exit();
2721 free_delayed_inode:
2722         btrfs_delayed_inode_exit();
2723 free_ordered_data:
2724         ordered_data_exit();
2725 free_extent_map:
2726         extent_map_exit();
2727 free_extent_state_cache:
2728         extent_state_cache_exit();
2729 free_extent_io:
2730         extent_io_exit();
2731 free_cachep:
2732         btrfs_destroy_cachep();
2733 free_compress:
2734         btrfs_exit_compress();
2735         btrfs_exit_sysfs();
2736
2737         return err;
2738 }
2739
2740 static void __exit exit_btrfs_fs(void)
2741 {
2742         btrfs_destroy_cachep();
2743         btrfs_delayed_ref_exit();
2744         btrfs_auto_defrag_exit();
2745         btrfs_delayed_inode_exit();
2746         btrfs_prelim_ref_exit();
2747         ordered_data_exit();
2748         extent_map_exit();
2749         extent_state_cache_exit();
2750         extent_io_exit();
2751         btrfs_interface_exit();
2752         unregister_filesystem(&btrfs_fs_type);
2753         btrfs_exit_sysfs();
2754         btrfs_cleanup_fs_uuids();
2755         btrfs_exit_compress();
2756 }
2757
2758 late_initcall(init_btrfs_fs);
2759 module_exit(exit_btrfs_fs)
2760
2761 MODULE_LICENSE("GPL");
2762 MODULE_SOFTDEP("pre: crc32c");
2763 MODULE_SOFTDEP("pre: xxhash64");
2764 MODULE_SOFTDEP("pre: sha256");
2765 MODULE_SOFTDEP("pre: blake2b-256");