fs/btrfs/super.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/blkdev.h>
   7 #include <linux/module.h>
   8 #include <linux/fs.h>
   9 #include <linux/pagemap.h>
  10 #include <linux/highmem.h>
  11 #include <linux/time.h>
  12 #include <linux/init.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/string.h>
  15 #include <linux/backing-dev.h>
  16 #include <linux/mount.h>
  17 #include <linux/writeback.h>
  18 #include <linux/statfs.h>
  19 #include <linux/compat.h>
  20 #include <linux/parser.h>
  21 #include <linux/ctype.h>
  22 #include <linux/namei.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/magic.h>
  25 #include <linux/slab.h>
  26 #include <linux/cleancache.h>
  27 #include <linux/ratelimit.h>
  28 #include <linux/crc32c.h>
  29 #include <linux/btrfs.h>
  30 #include "delayed-inode.h"
  31 #include "ctree.h"
  32 #include "disk-io.h"
  33 #include "transaction.h"
  34 #include "btrfs_inode.h"
  35 #include "print-tree.h"
  36 #include "props.h"
  37 #include "xattr.h"
  38 #include "volumes.h"
  39 #include "export.h"
  40 #include "compression.h"
  41 #include "rcu-string.h"
  42 #include "dev-replace.h"
  43 #include "free-space-cache.h"
  44 #include "backref.h"
  45 #include "space-info.h"
  46 #include "sysfs.h"
  47 #include "tests/btrfs-tests.h"
  48 #include "block-group.h"
  49 #include "discard.h"
  50
  51 #include "qgroup.h"
  52 #define CREATE_TRACE_POINTS
  53 #include <trace/events/btrfs.h>
  54
  55 static const struct super_operations btrfs_super_ops;
  56
  57 /*
  58  * Types for mounting the default subvolume and a subvolume explicitly
  59  * requested by subvol=/path. That way the callchain is straightforward and we
  60  * don't have to play tricks with the mount options and recursive calls to
  61  * btrfs_mount.
  62  *
  63  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
  64  */
  65 static struct file_system_type btrfs_fs_type;
  66 static struct file_system_type btrfs_root_fs_type;
  67
  68 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  69
  70 /*
  71  * Generally the error codes correspond to their respective errors, but there
  72  * are a few special cases.
  73  *
  74  * EUCLEAN: Any sort of corruption that we encounter.  The tree-checker for
  75  *          instance will return EUCLEAN if any of the blocks are corrupted in
  76  *          a way that is problematic.  We want to reserve EUCLEAN for these
  77  *          sort of corruptions.
  78  *
  79  * EROFS: If we check BTRFS_FS_STATE_ERROR and fail out with a return error, we
  80  *        need to use EROFS for this case.  We will have no idea of the
  81  *        original failure, that will have been reported at the time we tripped
  82  *        over the error.  Each subsequent error that doesn't have any context
  83  *        of the original error should use EROFS when handling BTRFS_FS_STATE_ERROR.
  84  */
  85 const char * __attribute_const__ btrfs_decode_error(int errno)
  86 {
  87         char *errstr = "unknown";
  88
  89         switch (errno) {
  90         case -ENOENT:           /* -2 */
  91                 errstr = "No such entry";
  92                 break;
  93         case -EIO:              /* -5 */
  94                 errstr = "IO failure";
  95                 break;
  96         case -ENOMEM:           /* -12*/
  97                 errstr = "Out of memory";
  98                 break;
  99         case -EEXIST:           /* -17 */
 100                 errstr = "Object already exists";
 101                 break;
 102         case -ENOSPC:           /* -28 */
 103                 errstr = "No space left";
 104                 break;
 105         case -EROFS:            /* -30 */
 106                 errstr = "Readonly filesystem";
 107                 break;
 108         case -EOPNOTSUPP:       /* -95 */
 109                 errstr = "Operation not supported";
 110                 break;
 111         case -EUCLEAN:          /* -117 */
 112                 errstr = "Filesystem corrupted";
 113                 break;
 114         case -EDQUOT:           /* -122 */
 115                 errstr = "Quota exceeded";
 116                 break;
 117         }
 118
 119         return errstr;
 120 }
 121
 122 /*
 123  * __btrfs_handle_fs_error decodes expected errors from the caller and
 124  * invokes the appropriate error response.
 125  */
 126 __cold
 127 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 128                        unsigned int line, int errno, const char *fmt, ...)
 129 {
 130         struct super_block *sb = fs_info->sb;
 131 #ifdef CONFIG_PRINTK
 132         const char *errstr;
 133 #endif
 134
 135         /*
 136          * Special case: if the error is EROFS, and we're already
 137          * under SB_RDONLY, then it is safe here.
 138          */
 139         if (errno == -EROFS && sb_rdonly(sb))
 140                 return;
 141
 142 #ifdef CONFIG_PRINTK
 143         errstr = btrfs_decode_error(errno);
 144         if (fmt) {
 145                 struct va_format vaf;
 146                 va_list args;
 147
 148                 va_start(args, fmt);
 149                 vaf.fmt = fmt;
 150                 vaf.va = &args;
 151
 152                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 153                         sb->s_id, function, line, errno, errstr, &vaf);
 154                 va_end(args);
 155         } else {
 156                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 157                         sb->s_id, function, line, errno, errstr);
 158         }
 159 #endif
 160
 161         /*
 162          * Today we only save the error info to memory.  Long term we'll
 163          * also send it down to the disk
 164          */
 165         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 166
 167         /* Don't go through full error handling during mount */
 168         if (!(sb->s_flags & SB_BORN))
 169                 return;
 170
 171         if (sb_rdonly(sb))
 172                 return;
 173
 174         btrfs_discard_stop(fs_info);
 175
 176         /* btrfs handle error by forcing the filesystem readonly */
 177         sb->s_flags |= SB_RDONLY;
 178         btrfs_info(fs_info, "forced readonly");
 179         /*
 180          * Note that a running device replace operation is not canceled here
 181          * although there is no way to update the progress. It would add the
 182          * risk of a deadlock, therefore the canceling is omitted. The only
 183          * penalty is that some I/O remains active until the procedure
 184          * completes. The next time when the filesystem is mounted writable
 185          * again, the device replace operation continues.
 186          */
 187 }
 188
 189 #ifdef CONFIG_PRINTK
 190 static const char * const logtypes[] = {
 191         "emergency",
 192         "alert",
 193         "critical",
 194         "error",
 195         "warning",
 196         "notice",
 197         "info",
 198         "debug",
 199 };
 200
 201
 202 /*
 203  * Use one ratelimit state per log level so that a flood of less important
 204  * messages doesn't cause more important ones to be dropped.
 205  */
 206 static struct ratelimit_state printk_limits[] = {
 207         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 208         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 209         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 210         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 211         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 212         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 213         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 214         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 215 };
 216
 217 void __cold btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 218 {
 219         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
 220         struct va_format vaf;
 221         va_list args;
 222         int kern_level;
 223         const char *type = logtypes[4];
 224         struct ratelimit_state *ratelimit = &printk_limits[4];
 225
 226         va_start(args, fmt);
 227
 228         while ((kern_level = printk_get_level(fmt)) != 0) {
 229                 size_t size = printk_skip_level(fmt) - fmt;
 230
 231                 if (kern_level >= '0' && kern_level <= '7') {
 232                         memcpy(lvl, fmt,  size);
 233                         lvl[size] = '\0';
 234                         type = logtypes[kern_level - '0'];
 235                         ratelimit = &printk_limits[kern_level - '0'];
 236                 }
 237                 fmt += size;
 238         }
 239
 240         vaf.fmt = fmt;
 241         vaf.va = &args;
 242
 243         if (__ratelimit(ratelimit))
 244                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type,
 245                         fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);
 246
 247         va_end(args);
 248 }
 249 #endif
 250
 251 /*
 252  * We only mark the transaction aborted and then set the file system read-only.
 253  * This will prevent new transactions from starting or trying to join this
 254  * one.
 255  *
 256  * This means that error recovery at the call site is limited to freeing
 257  * any local memory allocations and passing the error code up without
 258  * further cleanup. The transaction should complete as it normally would
 259  * in the call path but will return -EIO.
 260  *
 261  * We'll complete the cleanup in btrfs_end_transaction and
 262  * btrfs_commit_transaction.
 263  */
 264 __cold
 265 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 266                                const char *function,
 267                                unsigned int line, int errno)
 268 {
 269         struct btrfs_fs_info *fs_info = trans->fs_info;
 270
 271         WRITE_ONCE(trans->aborted, errno);
 272         /* Nothing used. The other threads that have joined this
 273          * transaction may be able to continue. */
 274         if (!trans->dirty && list_empty(&trans->new_bgs)) {
 275                 const char *errstr;
 276
 277                 errstr = btrfs_decode_error(errno);
 278                 btrfs_warn(fs_info,
 279                            "%s:%d: Aborting unused transaction(%s).",
 280                            function, line, errstr);
 281                 return;
 282         }
 283         WRITE_ONCE(trans->transaction->aborted, errno);
 284         /* Wake up anybody who may be waiting on this transaction */
 285         wake_up(&fs_info->transaction_wait);
 286         wake_up(&fs_info->transaction_blocked_wait);
 287         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 288 }
 289 /*
 290  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 291  * issues an alert, and either panics or BUGs, depending on mount options.
 292  */
 293 __cold
 294 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 295                    unsigned int line, int errno, const char *fmt, ...)
 296 {
 297         char *s_id = "<unknown>";
 298         const char *errstr;
 299         struct va_format vaf = { .fmt = fmt };
 300         va_list args;
 301
 302         if (fs_info)
 303                 s_id = fs_info->sb->s_id;
 304
 305         va_start(args, fmt);
 306         vaf.va = &args;
 307
 308         errstr = btrfs_decode_error(errno);
 309         if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
 310                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 311                         s_id, function, line, &vaf, errno, errstr);
 312
 313         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 314                    function, line, &vaf, errno, errstr);
 315         va_end(args);
 316         /* Caller calls BUG() */
 317 }
 318
 319 static void btrfs_put_super(struct super_block *sb)
 320 {
 321         close_ctree(btrfs_sb(sb));
 322 }
 323
 324 enum {
 325         Opt_acl, Opt_noacl,
 326         Opt_clear_cache,
 327         Opt_commit_interval,
 328         Opt_compress,
 329         Opt_compress_force,
 330         Opt_compress_force_type,
 331         Opt_compress_type,
 332         Opt_degraded,
 333         Opt_device,
 334         Opt_fatal_errors,
 335         Opt_flushoncommit, Opt_noflushoncommit,
 336         Opt_inode_cache, Opt_noinode_cache,
 337         Opt_max_inline,
 338         Opt_barrier, Opt_nobarrier,
 339         Opt_datacow, Opt_nodatacow,
 340         Opt_datasum, Opt_nodatasum,
 341         Opt_defrag, Opt_nodefrag,
 342         Opt_discard, Opt_nodiscard,
 343         Opt_discard_mode,
 344         Opt_norecovery,
 345         Opt_ratio,
 346         Opt_rescan_uuid_tree,
 347         Opt_skip_balance,
 348         Opt_space_cache, Opt_no_space_cache,
 349         Opt_space_cache_version,
 350         Opt_ssd, Opt_nossd,
 351         Opt_ssd_spread, Opt_nossd_spread,
 352         Opt_subvol,
 353         Opt_subvol_empty,
 354         Opt_subvolid,
 355         Opt_thread_pool,
 356         Opt_treelog, Opt_notreelog,
 357         Opt_user_subvol_rm_allowed,
 358
 359         /* Rescue options */
 360         Opt_rescue,
 361         Opt_usebackuproot,
 362         Opt_nologreplay,
 363
 364         /* Deprecated options */
 365         Opt_recovery,
 366
 367         /* Debugging options */
 368         Opt_check_integrity,
 369         Opt_check_integrity_including_extent_data,
 370         Opt_check_integrity_print_mask,
 371         Opt_enospc_debug, Opt_noenospc_debug,
 372 #ifdef CONFIG_BTRFS_DEBUG
 373         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 374 #endif
 375 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 376         Opt_ref_verify,
 377 #endif
 378         Opt_err,
 379 };
 380
 381 static const match_table_t tokens = {
 382         {Opt_acl, "acl"},
 383         {Opt_noacl, "noacl"},
 384         {Opt_clear_cache, "clear_cache"},
 385         {Opt_commit_interval, "commit=%u"},
 386         {Opt_compress, "compress"},
 387         {Opt_compress_type, "compress=%s"},
 388         {Opt_compress_force, "compress-force"},
 389         {Opt_compress_force_type, "compress-force=%s"},
 390         {Opt_degraded, "degraded"},
 391         {Opt_device, "device=%s"},
 392         {Opt_fatal_errors, "fatal_errors=%s"},
 393         {Opt_flushoncommit, "flushoncommit"},
 394         {Opt_noflushoncommit, "noflushoncommit"},
 395         {Opt_inode_cache, "inode_cache"},
 396         {Opt_noinode_cache, "noinode_cache"},
 397         {Opt_max_inline, "max_inline=%s"},
 398         {Opt_barrier, "barrier"},
 399         {Opt_nobarrier, "nobarrier"},
 400         {Opt_datacow, "datacow"},
 401         {Opt_nodatacow, "nodatacow"},
 402         {Opt_datasum, "datasum"},
 403         {Opt_nodatasum, "nodatasum"},
 404         {Opt_defrag, "autodefrag"},
 405         {Opt_nodefrag, "noautodefrag"},
 406         {Opt_discard, "discard"},
 407         {Opt_discard_mode, "discard=%s"},
 408         {Opt_nodiscard, "nodiscard"},
 409         {Opt_norecovery, "norecovery"},
 410         {Opt_ratio, "metadata_ratio=%u"},
 411         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 412         {Opt_skip_balance, "skip_balance"},
 413         {Opt_space_cache, "space_cache"},
 414         {Opt_no_space_cache, "nospace_cache"},
 415         {Opt_space_cache_version, "space_cache=%s"},
 416         {Opt_ssd, "ssd"},
 417         {Opt_nossd, "nossd"},
 418         {Opt_ssd_spread, "ssd_spread"},
 419         {Opt_nossd_spread, "nossd_spread"},
 420         {Opt_subvol, "subvol=%s"},
 421         {Opt_subvol_empty, "subvol="},
 422         {Opt_subvolid, "subvolid=%s"},
 423         {Opt_thread_pool, "thread_pool=%u"},
 424         {Opt_treelog, "treelog"},
 425         {Opt_notreelog, "notreelog"},
 426         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 427
 428         /* Rescue options */
 429         {Opt_rescue, "rescue=%s"},
 430         /* Deprecated, with alias rescue=nologreplay */
 431         {Opt_nologreplay, "nologreplay"},
 432         /* Deprecated, with alias rescue=usebackuproot */
 433         {Opt_usebackuproot, "usebackuproot"},
 434
 435         /* Deprecated options */
 436         {Opt_recovery, "recovery"},
 437
 438         /* Debugging options */
 439         {Opt_check_integrity, "check_int"},
 440         {Opt_check_integrity_including_extent_data, "check_int_data"},
 441         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
 442         {Opt_enospc_debug, "enospc_debug"},
 443         {Opt_noenospc_debug, "noenospc_debug"},
 444 #ifdef CONFIG_BTRFS_DEBUG
 445         {Opt_fragment_data, "fragment=data"},
 446         {Opt_fragment_metadata, "fragment=metadata"},
 447         {Opt_fragment_all, "fragment=all"},
 448 #endif
 449 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 450         {Opt_ref_verify, "ref_verify"},
 451 #endif
 452         {Opt_err, NULL},
 453 };
 454
 455 static const match_table_t rescue_tokens = {
 456         {Opt_usebackuproot, "usebackuproot"},
 457         {Opt_nologreplay, "nologreplay"},
 458         {Opt_err, NULL},
 459 };
 460
 461 static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
 462 {
 463         char *opts;
 464         char *orig;
 465         char *p;
 466         substring_t args[MAX_OPT_ARGS];
 467         int ret = 0;
 468
 469         opts = kstrdup(options, GFP_KERNEL);
 470         if (!opts)
 471                 return -ENOMEM;
 472         orig = opts;
 473
 474         while ((p = strsep(&opts, ":")) != NULL) {
 475                 int token;
 476
 477                 if (!*p)
 478                         continue;
 479                 token = match_token(p, rescue_tokens, args);
 480                 switch (token){
 481                 case Opt_usebackuproot:
 482                         btrfs_info(info,
 483                                    "trying to use backup root at mount time");
 484                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 485                         break;
 486                 case Opt_nologreplay:
 487                         btrfs_set_and_info(info, NOLOGREPLAY,
 488                                            "disabling log replay at mount time");
 489                         break;
 490                 case Opt_err:
 491                         btrfs_info(info, "unrecognized rescue option '%s'", p);
 492                         ret = -EINVAL;
 493                         goto out;
 494                 default:
 495                         break;
 496                 }
 497
 498         }
 499 out:
 500         kfree(orig);
 501         return ret;
 502 }
 503
 504 /*
 505  * Regular mount options parser.  Everything that is needed only when
 506  * reading in a new superblock is parsed here.
 507  * XXX JDM: This needs to be cleaned up for remount.
 508  */
 509 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 510                         unsigned long new_flags)
 511 {
 512         substring_t args[MAX_OPT_ARGS];
 513         char *p, *num;
 514         u64 cache_gen;
 515         int intarg;
 516         int ret = 0;
 517         char *compress_type;
 518         bool compress_force = false;
 519         enum btrfs_compression_type saved_compress_type;
 520         int saved_compress_level;
 521         bool saved_compress_force;
 522         int no_compress = 0;
 523
 524         cache_gen = btrfs_super_cache_generation(info->super_copy);
 525         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 526                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 527         else if (cache_gen)
 528                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 529
 530         /*
 531          * Even the options are empty, we still need to do extra check
 532          * against new flags
 533          */
 534         if (!options)
 535                 goto check;
 536
 537         while ((p = strsep(&options, ",")) != NULL) {
 538                 int token;
 539                 if (!*p)
 540                         continue;
 541
 542                 token = match_token(p, tokens, args);
 543                 switch (token) {
 544                 case Opt_degraded:
 545                         btrfs_info(info, "allowing degraded mounts");
 546                         btrfs_set_opt(info->mount_opt, DEGRADED);
 547                         break;
 548                 case Opt_subvol:
 549                 case Opt_subvol_empty:
 550                 case Opt_subvolid:
 551                 case Opt_device:
 552                         /*
 553                          * These are parsed by btrfs_parse_subvol_options or
 554                          * btrfs_parse_device_options and can be ignored here.
 555                          */
 556                         break;
 557                 case Opt_nodatasum:
 558                         btrfs_set_and_info(info, NODATASUM,
 559                                            "setting nodatasum");
 560                         break;
 561                 case Opt_datasum:
 562                         if (btrfs_test_opt(info, NODATASUM)) {
 563                                 if (btrfs_test_opt(info, NODATACOW))
 564                                         btrfs_info(info,
 565                                                    "setting datasum, datacow enabled");
 566                                 else
 567                                         btrfs_info(info, "setting datasum");
 568                         }
 569                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 570                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 571                         break;
 572                 case Opt_nodatacow:
 573                         if (!btrfs_test_opt(info, NODATACOW)) {
 574                                 if (!btrfs_test_opt(info, COMPRESS) ||
 575                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 576                                         btrfs_info(info,
 577                                                    "setting nodatacow, compression disabled");
 578                                 } else {
 579                                         btrfs_info(info, "setting nodatacow");
 580                                 }
 581                         }
 582                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 583                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 584                         btrfs_set_opt(info->mount_opt, NODATACOW);
 585                         btrfs_set_opt(info->mount_opt, NODATASUM);
 586                         break;
 587                 case Opt_datacow:
 588                         btrfs_clear_and_info(info, NODATACOW,
 589                                              "setting datacow");
 590                         break;
 591                 case Opt_compress_force:
 592                 case Opt_compress_force_type:
 593                         compress_force = true;
 594                         fallthrough;
 595                 case Opt_compress:
 596                 case Opt_compress_type:
 597                         saved_compress_type = btrfs_test_opt(info,
 598                                                              COMPRESS) ?
 599                                 info->compress_type : BTRFS_COMPRESS_NONE;
 600                         saved_compress_force =
 601                                 btrfs_test_opt(info, FORCE_COMPRESS);
 602                         saved_compress_level = info->compress_level;
 603                         if (token == Opt_compress ||
 604                             token == Opt_compress_force ||
 605                             strncmp(args[0].from, "zlib", 4) == 0) {
 606                                 compress_type = "zlib";
 607
 608                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 609                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 610                                 /*
 611                                  * args[0] contains uninitialized data since
 612                                  * for these tokens we don't expect any
 613                                  * parameter.
 614                                  */
 615                                 if (token != Opt_compress &&
 616                                     token != Opt_compress_force)
 617                                         info->compress_level =
 618                                           btrfs_compress_str2level(
 619                                                         BTRFS_COMPRESS_ZLIB,
 620                                                         args[0].from + 4);
 621                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 622                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 623                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 624                                 no_compress = 0;
 625                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 626                                 compress_type = "lzo";
 627                                 info->compress_type = BTRFS_COMPRESS_LZO;
 628                                 info->compress_level = 0;
 629                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 630                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 631                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 632                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 633                                 no_compress = 0;
 634                         } else if (strncmp(args[0].from, "zstd", 4) == 0) {
 635                                 compress_type = "zstd";
 636                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 637                                 info->compress_level =
 638                                         btrfs_compress_str2level(
 639                                                          BTRFS_COMPRESS_ZSTD,
 640                                                          args[0].from + 4);
 641                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 642                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 643                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 644                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 645                                 no_compress = 0;
 646                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 647                                 compress_type = "no";
 648                                 info->compress_level = 0;
 649                                 info->compress_type = 0;
 650                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 651                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 652                                 compress_force = false;
 653                                 no_compress++;
 654                         } else {
 655                                 ret = -EINVAL;
 656                                 goto out;
 657                         }
 658
 659                         if (compress_force) {
 660                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 661                         } else {
 662                                 /*
 663                                  * If we remount from compress-force=xxx to
 664                                  * compress=xxx, we need clear FORCE_COMPRESS
 665                                  * flag, otherwise, there is no way for users
 666                                  * to disable forcible compression separately.
 667                                  */
 668                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 669                         }
 670                         if (no_compress == 1) {
 671                                 btrfs_info(info, "use no compression");
 672                         } else if ((info->compress_type != saved_compress_type) ||
 673                                    (compress_force != saved_compress_force) ||
 674                                    (info->compress_level != saved_compress_level)) {
 675                                 btrfs_info(info, "%s %s compression, level %d",
 676                                            (compress_force) ? "force" : "use",
 677                                            compress_type, info->compress_level);
 678                         }
 679                         compress_force = false;
 680                         break;
 681                 case Opt_ssd:
 682                         btrfs_set_and_info(info, SSD,
 683                                            "enabling ssd optimizations");
 684                         btrfs_clear_opt(info->mount_opt, NOSSD);
 685                         break;
 686                 case Opt_ssd_spread:
 687                         btrfs_set_and_info(info, SSD,
 688                                            "enabling ssd optimizations");
 689                         btrfs_set_and_info(info, SSD_SPREAD,
 690                                            "using spread ssd allocation scheme");
 691                         btrfs_clear_opt(info->mount_opt, NOSSD);
 692                         break;
 693                 case Opt_nossd:
 694                         btrfs_set_opt(info->mount_opt, NOSSD);
 695                         btrfs_clear_and_info(info, SSD,
 696                                              "not using ssd optimizations");
 697                         fallthrough;
 698                 case Opt_nossd_spread:
 699                         btrfs_clear_and_info(info, SSD_SPREAD,
 700                                              "not using spread ssd allocation scheme");
 701                         break;
 702                 case Opt_barrier:
 703                         btrfs_clear_and_info(info, NOBARRIER,
 704                                              "turning on barriers");
 705                         break;
 706                 case Opt_nobarrier:
 707                         btrfs_set_and_info(info, NOBARRIER,
 708                                            "turning off barriers");
 709                         break;
 710                 case Opt_thread_pool:
 711                         ret = match_int(&args[0], &intarg);
 712                         if (ret) {
 713                                 goto out;
 714                         } else if (intarg == 0) {
 715                                 ret = -EINVAL;
 716                                 goto out;
 717                         }
 718                         info->thread_pool_size = intarg;
 719                         break;
 720                 case Opt_max_inline:
 721                         num = match_strdup(&args[0]);
 722                         if (num) {
 723                                 info->max_inline = memparse(num, NULL);
 724                                 kfree(num);
 725
 726                                 if (info->max_inline) {
 727                                         info->max_inline = min_t(u64,
 728                                                 info->max_inline,
 729                                                 info->sectorsize);
 730                                 }
 731                                 btrfs_info(info, "max_inline at %llu",
 732                                            info->max_inline);
 733                         } else {
 734                                 ret = -ENOMEM;
 735                                 goto out;
 736                         }
 737                         break;
 738                 case Opt_acl:
 739 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 740                         info->sb->s_flags |= SB_POSIXACL;
 741                         break;
 742 #else
 743                         btrfs_err(info, "support for ACL not compiled in!");
 744                         ret = -EINVAL;
 745                         goto out;
 746 #endif
 747                 case Opt_noacl:
 748                         info->sb->s_flags &= ~SB_POSIXACL;
 749                         break;
 750                 case Opt_notreelog:
 751                         btrfs_set_and_info(info, NOTREELOG,
 752                                            "disabling tree log");
 753                         break;
 754                 case Opt_treelog:
 755                         btrfs_clear_and_info(info, NOTREELOG,
 756                                              "enabling tree log");
 757                         break;
 758                 case Opt_norecovery:
 759                 case Opt_nologreplay:
 760                         btrfs_warn(info,
 761                 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
 762                         btrfs_set_and_info(info, NOLOGREPLAY,
 763                                            "disabling log replay at mount time");
 764                         break;
 765                 case Opt_flushoncommit:
 766                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 767                                            "turning on flush-on-commit");
 768                         break;
 769                 case Opt_noflushoncommit:
 770                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 771                                              "turning off flush-on-commit");
 772                         break;
 773                 case Opt_ratio:
 774                         ret = match_int(&args[0], &intarg);
 775                         if (ret)
 776                                 goto out;
 777                         info->metadata_ratio = intarg;
 778                         btrfs_info(info, "metadata ratio %u",
 779                                    info->metadata_ratio);
 780                         break;
 781                 case Opt_discard:
 782                 case Opt_discard_mode:
 783                         if (token == Opt_discard ||
 784                             strcmp(args[0].from, "sync") == 0) {
 785                                 btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
 786                                 btrfs_set_and_info(info, DISCARD_SYNC,
 787                                                    "turning on sync discard");
 788                         } else if (strcmp(args[0].from, "async") == 0) {
 789                                 btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
 790                                 btrfs_set_and_info(info, DISCARD_ASYNC,
 791                                                    "turning on async discard");
 792                         } else {
 793                                 ret = -EINVAL;
 794                                 goto out;
 795                         }
 796                         break;
 797                 case Opt_nodiscard:
 798                         btrfs_clear_and_info(info, DISCARD_SYNC,
 799                                              "turning off discard");
 800                         btrfs_clear_and_info(info, DISCARD_ASYNC,
 801                                              "turning off async discard");
 802                         break;
 803                 case Opt_space_cache:
 804                 case Opt_space_cache_version:
 805                         if (token == Opt_space_cache ||
 806                             strcmp(args[0].from, "v1") == 0) {
 807                                 btrfs_clear_opt(info->mount_opt,
 808                                                 FREE_SPACE_TREE);
 809                                 btrfs_set_and_info(info, SPACE_CACHE,
 810                                            "enabling disk space caching");
 811                         } else if (strcmp(args[0].from, "v2") == 0) {
 812                                 btrfs_clear_opt(info->mount_opt,
 813                                                 SPACE_CACHE);
 814                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 815                                                    "enabling free space tree");
 816                         } else {
 817                                 ret = -EINVAL;
 818                                 goto out;
 819                         }
 820                         break;
 821                 case Opt_rescan_uuid_tree:
 822                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 823                         break;
 824                 case Opt_no_space_cache:
 825                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 826                                 btrfs_clear_and_info(info, SPACE_CACHE,
 827                                              "disabling disk space caching");
 828                         }
 829                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 830                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 831                                              "disabling free space tree");
 832                         }
 833                         break;
 834                 case Opt_inode_cache:
 835                         btrfs_warn(info,
 836         "the 'inode_cache' option is deprecated and will have no effect from 5.11");
 837                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 838                                            "enabling inode map caching");
 839                         break;
 840                 case Opt_noinode_cache:
 841                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 842                                              "disabling inode map caching");
 843                         break;
 844                 case Opt_clear_cache:
 845                         btrfs_set_and_info(info, CLEAR_CACHE,
 846                                            "force clearing of disk cache");
 847                         break;
 848                 case Opt_user_subvol_rm_allowed:
 849                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 850                         break;
 851                 case Opt_enospc_debug:
 852                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 853                         break;
 854                 case Opt_noenospc_debug:
 855                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 856                         break;
 857                 case Opt_defrag:
 858                         btrfs_set_and_info(info, AUTO_DEFRAG,
 859                                            "enabling auto defrag");
 860                         break;
 861                 case Opt_nodefrag:
 862                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 863                                              "disabling auto defrag");
 864                         break;
 865                 case Opt_recovery:
 866                 case Opt_usebackuproot:
 867                         btrfs_warn(info,
 868                         "'%s' is deprecated, use 'rescue=usebackuproot' instead",
 869                                    token == Opt_recovery ? "recovery" :
 870                                    "usebackuproot");
 871                         btrfs_info(info,
 872                                    "trying to use backup root at mount time");
 873                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 874                         break;
 875                 case Opt_skip_balance:
 876                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 877                         break;
 878 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 879                 case Opt_check_integrity_including_extent_data:
 880                         btrfs_info(info,
 881                                    "enabling check integrity including extent data");
 882                         btrfs_set_opt(info->mount_opt,
 883                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 884                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 885                         break;
 886                 case Opt_check_integrity:
 887                         btrfs_info(info, "enabling check integrity");
 888                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 889                         break;
 890                 case Opt_check_integrity_print_mask:
 891                         ret = match_int(&args[0], &intarg);
 892                         if (ret)
 893                                 goto out;
 894                         info->check_integrity_print_mask = intarg;
 895                         btrfs_info(info, "check_integrity_print_mask 0x%x",
 896                                    info->check_integrity_print_mask);
 897                         break;
 898 #else
 899                 case Opt_check_integrity_including_extent_data:
 900                 case Opt_check_integrity:
 901                 case Opt_check_integrity_print_mask:
 902                         btrfs_err(info,
 903                                   "support for check_integrity* not compiled in!");
 904                         ret = -EINVAL;
 905                         goto out;
 906 #endif
 907                 case Opt_fatal_errors:
 908                         if (strcmp(args[0].from, "panic") == 0)
 909                                 btrfs_set_opt(info->mount_opt,
 910                                               PANIC_ON_FATAL_ERROR);
 911                         else if (strcmp(args[0].from, "bug") == 0)
 912                                 btrfs_clear_opt(info->mount_opt,
 913                                               PANIC_ON_FATAL_ERROR);
 914                         else {
 915                                 ret = -EINVAL;
 916                                 goto out;
 917                         }
 918                         break;
 919                 case Opt_commit_interval:
 920                         intarg = 0;
 921                         ret = match_int(&args[0], &intarg);
 922                         if (ret)
 923                                 goto out;
 924                         if (intarg == 0) {
 925                                 btrfs_info(info,
 926                                            "using default commit interval %us",
 927                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 928                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
 929                         } else if (intarg > 300) {
 930                                 btrfs_warn(info, "excessive commit interval %d",
 931                                            intarg);
 932                         }
 933                         info->commit_interval = intarg;
 934                         break;
 935                 case Opt_rescue:
 936                         ret = parse_rescue_options(info, args[0].from);
 937                         if (ret < 0)
 938                                 goto out;
 939                         break;
 940 #ifdef CONFIG_BTRFS_DEBUG
 941                 case Opt_fragment_all:
 942                         btrfs_info(info, "fragmenting all space");
 943                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 944                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 945                         break;
 946                 case Opt_fragment_metadata:
 947                         btrfs_info(info, "fragmenting metadata");
 948                         btrfs_set_opt(info->mount_opt,
 949                                       FRAGMENT_METADATA);
 950                         break;
 951                 case Opt_fragment_data:
 952                         btrfs_info(info, "fragmenting data");
 953                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 954                         break;
 955 #endif
 956 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 957                 case Opt_ref_verify:
 958                         btrfs_info(info, "doing ref verification");
 959                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 960                         break;
 961 #endif
 962                 case Opt_err:
 963                         btrfs_err(info, "unrecognized mount option '%s'", p);
 964                         ret = -EINVAL;
 965                         goto out;
 966                 default:
 967                         break;
 968                 }
 969         }
 970 check:
 971         /*
 972          * Extra check for current option against current flag
 973          */
 974         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & SB_RDONLY)) {
 975                 btrfs_err(info,
 976                           "nologreplay must be used with ro mount option");
 977                 ret = -EINVAL;
 978         }
 979 out:
 980         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 981             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 982             !btrfs_test_opt(info, CLEAR_CACHE)) {
 983                 btrfs_err(info, "cannot disable free space tree");
 984                 ret = -EINVAL;
 985
 986         }
 987         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 988                 btrfs_info(info, "disk space caching is enabled");
 989         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 990                 btrfs_info(info, "using free space tree");
 991         return ret;
 992 }
 993
 994 /*
 995  * Parse mount options that are required early in the mount process.
 996  *
 997  * All other options will be parsed on much later in the mount process and
 998  * only when we need to allocate a new super block.
 999  */
1000 static int btrfs_parse_device_options(const char *options, fmode_t flags,
1001                                       void *holder)
1002 {
1003         substring_t args[MAX_OPT_ARGS];
1004         char *device_name, *opts, *orig, *p;
1005         struct btrfs_device *device = NULL;
1006         int error = 0;
1007
1008         lockdep_assert_held(&uuid_mutex);
1009
1010         if (!options)
1011                 return 0;
1012
1013         /*
1014          * strsep changes the string, duplicate it because btrfs_parse_options
1015          * gets called later
1016          */
1017         opts = kstrdup(options, GFP_KERNEL);
1018         if (!opts)
1019                 return -ENOMEM;
1020         orig = opts;
1021
1022         while ((p = strsep(&opts, ",")) != NULL) {
1023                 int token;
1024
1025                 if (!*p)
1026                         continue;
1027
1028                 token = match_token(p, tokens, args);
1029                 if (token == Opt_device) {
1030                         device_name = match_strdup(&args[0]);
1031                         if (!device_name) {
1032                                 error = -ENOMEM;
1033                                 goto out;
1034                         }
1035                         device = btrfs_scan_one_device(device_name, flags,
1036                                         holder);
1037                         kfree(device_name);
1038                         if (IS_ERR(device)) {
1039                                 error = PTR_ERR(device);
1040                                 goto out;
1041                         }
1042                 }
1043         }
1044
1045 out:
1046         kfree(orig);
1047         return error;
1048 }
1049
1050 /*
1051  * Parse mount options that are related to subvolume id
1052  *
1053  * The value is later passed to mount_subvol()
1054  */
1055 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
1056                 u64 *subvol_objectid)
1057 {
1058         substring_t args[MAX_OPT_ARGS];
1059         char *opts, *orig, *p;
1060         int error = 0;
1061         u64 subvolid;
1062
1063         if (!options)
1064                 return 0;
1065
1066         /*
1067          * strsep changes the string, duplicate it because
1068          * btrfs_parse_device_options gets called later
1069          */
1070         opts = kstrdup(options, GFP_KERNEL);
1071         if (!opts)
1072                 return -ENOMEM;
1073         orig = opts;
1074
1075         while ((p = strsep(&opts, ",")) != NULL) {
1076                 int token;
1077                 if (!*p)
1078                         continue;
1079
1080                 token = match_token(p, tokens, args);
1081                 switch (token) {
1082                 case Opt_subvol:
1083                         kfree(*subvol_name);
1084                         *subvol_name = match_strdup(&args[0]);
1085                         if (!*subvol_name) {
1086                                 error = -ENOMEM;
1087                                 goto out;
1088                         }
1089                         break;
1090                 case Opt_subvolid:
1091                         error = match_u64(&args[0], &subvolid);
1092                         if (error)
1093                                 goto out;
1094
1095                         /* we want the original fs_tree */
1096                         if (subvolid == 0)
1097                                 subvolid = BTRFS_FS_TREE_OBJECTID;
1098
1099                         *subvol_objectid = subvolid;
1100                         break;
1101                 default:
1102                         break;
1103                 }
1104         }
1105
1106 out:
1107         kfree(orig);
1108         return error;
1109 }
1110
1111 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
1112                                           u64 subvol_objectid)
1113 {
1114         struct btrfs_root *root = fs_info->tree_root;
1115         struct btrfs_root *fs_root = NULL;
1116         struct btrfs_root_ref *root_ref;
1117         struct btrfs_inode_ref *inode_ref;
1118         struct btrfs_key key;
1119         struct btrfs_path *path = NULL;
1120         char *name = NULL, *ptr;
1121         u64 dirid;
1122         int len;
1123         int ret;
1124
1125         path = btrfs_alloc_path();
1126         if (!path) {
1127                 ret = -ENOMEM;
1128                 goto err;
1129         }
1130         path->leave_spinning = 1;
1131
1132         name = kmalloc(PATH_MAX, GFP_KERNEL);
1133         if (!name) {
1134                 ret = -ENOMEM;
1135                 goto err;
1136         }
1137         ptr = name + PATH_MAX - 1;
1138         ptr[0] = '\0';
1139
1140         /*
1141          * Walk up the subvolume trees in the tree of tree roots by root
1142          * backrefs until we hit the top-level subvolume.
1143          */
1144         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1145                 key.objectid = subvol_objectid;
1146                 key.type = BTRFS_ROOT_BACKREF_KEY;
1147                 key.offset = (u64)-1;
1148
1149                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1150                 if (ret < 0) {
1151                         goto err;
1152                 } else if (ret > 0) {
1153                         ret = btrfs_previous_item(root, path, subvol_objectid,
1154                                                   BTRFS_ROOT_BACKREF_KEY);
1155                         if (ret < 0) {
1156                                 goto err;
1157                         } else if (ret > 0) {
1158                                 ret = -ENOENT;
1159                                 goto err;
1160                         }
1161                 }
1162
1163                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1164                 subvol_objectid = key.offset;
1165
1166                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1167                                           struct btrfs_root_ref);
1168                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1169                 ptr -= len + 1;
1170                 if (ptr < name) {
1171                         ret = -ENAMETOOLONG;
1172                         goto err;
1173                 }
1174                 read_extent_buffer(path->nodes[0], ptr + 1,
1175                                    (unsigned long)(root_ref + 1), len);
1176                 ptr[0] = '/';
1177                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1178                 btrfs_release_path(path);
1179
1180                 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
1181                 if (IS_ERR(fs_root)) {
1182                         ret = PTR_ERR(fs_root);
1183                         fs_root = NULL;
1184                         goto err;
1185                 }
1186
1187                 /*
1188                  * Walk up the filesystem tree by inode refs until we hit the
1189                  * root directory.
1190                  */
1191                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1192                         key.objectid = dirid;
1193                         key.type = BTRFS_INODE_REF_KEY;
1194                         key.offset = (u64)-1;
1195
1196                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1197                         if (ret < 0) {
1198                                 goto err;
1199                         } else if (ret > 0) {
1200                                 ret = btrfs_previous_item(fs_root, path, dirid,
1201                                                           BTRFS_INODE_REF_KEY);
1202                                 if (ret < 0) {
1203                                         goto err;
1204                                 } else if (ret > 0) {
1205                                         ret = -ENOENT;
1206                                         goto err;
1207                                 }
1208                         }
1209
1210                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1211                         dirid = key.offset;
1212
1213                         inode_ref = btrfs_item_ptr(path->nodes[0],
1214                                                    path->slots[0],
1215                                                    struct btrfs_inode_ref);
1216                         len = btrfs_inode_ref_name_len(path->nodes[0],
1217                                                        inode_ref);
1218                         ptr -= len + 1;
1219                         if (ptr < name) {
1220                                 ret = -ENAMETOOLONG;
1221                                 goto err;
1222                         }
1223                         read_extent_buffer(path->nodes[0], ptr + 1,
1224                                            (unsigned long)(inode_ref + 1), len);
1225                         ptr[0] = '/';
1226                         btrfs_release_path(path);
1227                 }
1228                 btrfs_put_root(fs_root);
1229                 fs_root = NULL;
1230         }
1231
1232         btrfs_free_path(path);
1233         if (ptr == name + PATH_MAX - 1) {
1234                 name[0] = '/';
1235                 name[1] = '\0';
1236         } else {
1237                 memmove(name, ptr, name + PATH_MAX - ptr);
1238         }
1239         return name;
1240
1241 err:
1242         btrfs_put_root(fs_root);
1243         btrfs_free_path(path);
1244         kfree(name);
1245         return ERR_PTR(ret);
1246 }
1247
1248 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1249 {
1250         struct btrfs_root *root = fs_info->tree_root;
1251         struct btrfs_dir_item *di;
1252         struct btrfs_path *path;
1253         struct btrfs_key location;
1254         u64 dir_id;
1255
1256         path = btrfs_alloc_path();
1257         if (!path)
1258                 return -ENOMEM;
1259         path->leave_spinning = 1;
1260
1261         /*
1262          * Find the "default" dir item which points to the root item that we
1263          * will mount by default if we haven't been given a specific subvolume
1264          * to mount.
1265          */
1266         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1267         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1268         if (IS_ERR(di)) {
1269                 btrfs_free_path(path);
1270                 return PTR_ERR(di);
1271         }
1272         if (!di) {
1273                 /*
1274                  * Ok the default dir item isn't there.  This is weird since
1275                  * it's always been there, but don't freak out, just try and
1276                  * mount the top-level subvolume.
1277                  */
1278                 btrfs_free_path(path);
1279                 *objectid = BTRFS_FS_TREE_OBJECTID;
1280                 return 0;
1281         }
1282
1283         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1284         btrfs_free_path(path);
1285         *objectid = location.objectid;
1286         return 0;
1287 }
1288
1289 static int btrfs_fill_super(struct super_block *sb,
1290                             struct btrfs_fs_devices *fs_devices,
1291                             void *data)
1292 {
1293         struct inode *inode;
1294         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1295         int err;
1296
1297         sb->s_maxbytes = MAX_LFS_FILESIZE;
1298         sb->s_magic = BTRFS_SUPER_MAGIC;
1299         sb->s_op = &btrfs_super_ops;
1300         sb->s_d_op = &btrfs_dentry_operations;
1301         sb->s_export_op = &btrfs_export_ops;
1302         sb->s_xattr = btrfs_xattr_handlers;
1303         sb->s_time_gran = 1;
1304 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1305         sb->s_flags |= SB_POSIXACL;
1306 #endif
1307         sb->s_flags |= SB_I_VERSION;
1308         sb->s_iflags |= SB_I_CGROUPWB;
1309
1310         err = super_setup_bdi(sb);
1311         if (err) {
1312                 btrfs_err(fs_info, "super_setup_bdi failed");
1313                 return err;
1314         }
1315
1316         err = open_ctree(sb, fs_devices, (char *)data);
1317         if (err) {
1318                 btrfs_err(fs_info, "open_ctree failed");
1319                 return err;
1320         }
1321
1322         inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1323         if (IS_ERR(inode)) {
1324                 err = PTR_ERR(inode);
1325                 goto fail_close;
1326         }
1327
1328         sb->s_root = d_make_root(inode);
1329         if (!sb->s_root) {
1330                 err = -ENOMEM;
1331                 goto fail_close;
1332         }
1333
1334         cleancache_init_fs(sb);
1335         sb->s_flags |= SB_ACTIVE;
1336         return 0;
1337
1338 fail_close:
1339         close_ctree(fs_info);
1340         return err;
1341 }
1342
1343 int btrfs_sync_fs(struct super_block *sb, int wait)
1344 {
1345         struct btrfs_trans_handle *trans;
1346         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1347         struct btrfs_root *root = fs_info->tree_root;
1348
1349         trace_btrfs_sync_fs(fs_info, wait);
1350
1351         if (!wait) {
1352                 filemap_flush(fs_info->btree_inode->i_mapping);
1353                 return 0;
1354         }
1355
1356         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1357
1358         trans = btrfs_attach_transaction_barrier(root);
1359         if (IS_ERR(trans)) {
1360                 /* no transaction, don't bother */
1361                 if (PTR_ERR(trans) == -ENOENT) {
1362                         /*
1363                          * Exit unless we have some pending changes
1364                          * that need to go through commit
1365                          */
1366                         if (fs_info->pending_changes == 0)
1367                                 return 0;
1368                         /*
1369                          * A non-blocking test if the fs is frozen. We must not
1370                          * start a new transaction here otherwise a deadlock
1371                          * happens. The pending operations are delayed to the
1372                          * next commit after thawing.
1373                          */
1374                         if (sb_start_write_trylock(sb))
1375                                 sb_end_write(sb);
1376                         else
1377                                 return 0;
1378                         trans = btrfs_start_transaction(root, 0);
1379                 }
1380                 if (IS_ERR(trans))
1381                         return PTR_ERR(trans);
1382         }
1383         return btrfs_commit_transaction(trans);
1384 }
1385
1386 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1387 {
1388         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1389         const char *compress_type;
1390         const char *subvol_name;
1391
1392         if (btrfs_test_opt(info, DEGRADED))
1393                 seq_puts(seq, ",degraded");
1394         if (btrfs_test_opt(info, NODATASUM))
1395                 seq_puts(seq, ",nodatasum");
1396         if (btrfs_test_opt(info, NODATACOW))
1397                 seq_puts(seq, ",nodatacow");
1398         if (btrfs_test_opt(info, NOBARRIER))
1399                 seq_puts(seq, ",nobarrier");
1400         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1401                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1402         if (info->thread_pool_size !=  min_t(unsigned long,
1403                                              num_online_cpus() + 2, 8))
1404                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1405         if (btrfs_test_opt(info, COMPRESS)) {
1406                 compress_type = btrfs_compress_type2str(info->compress_type);
1407                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1408                         seq_printf(seq, ",compress-force=%s", compress_type);
1409                 else
1410                         seq_printf(seq, ",compress=%s", compress_type);
1411                 if (info->compress_level)
1412                         seq_printf(seq, ":%d", info->compress_level);
1413         }
1414         if (btrfs_test_opt(info, NOSSD))
1415                 seq_puts(seq, ",nossd");
1416         if (btrfs_test_opt(info, SSD_SPREAD))
1417                 seq_puts(seq, ",ssd_spread");
1418         else if (btrfs_test_opt(info, SSD))
1419                 seq_puts(seq, ",ssd");
1420         if (btrfs_test_opt(info, NOTREELOG))
1421                 seq_puts(seq, ",notreelog");
1422         if (btrfs_test_opt(info, NOLOGREPLAY))
1423                 seq_puts(seq, ",rescue=nologreplay");
1424         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1425                 seq_puts(seq, ",flushoncommit");
1426         if (btrfs_test_opt(info, DISCARD_SYNC))
1427                 seq_puts(seq, ",discard");
1428         if (btrfs_test_opt(info, DISCARD_ASYNC))
1429                 seq_puts(seq, ",discard=async");
1430         if (!(info->sb->s_flags & SB_POSIXACL))
1431                 seq_puts(seq, ",noacl");
1432         if (btrfs_test_opt(info, SPACE_CACHE))
1433                 seq_puts(seq, ",space_cache");
1434         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1435                 seq_puts(seq, ",space_cache=v2");
1436         else
1437                 seq_puts(seq, ",nospace_cache");
1438         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1439                 seq_puts(seq, ",rescan_uuid_tree");
1440         if (btrfs_test_opt(info, CLEAR_CACHE))
1441                 seq_puts(seq, ",clear_cache");
1442         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1443                 seq_puts(seq, ",user_subvol_rm_allowed");
1444         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1445                 seq_puts(seq, ",enospc_debug");
1446         if (btrfs_test_opt(info, AUTO_DEFRAG))
1447                 seq_puts(seq, ",autodefrag");
1448         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1449                 seq_puts(seq, ",inode_cache");
1450         if (btrfs_test_opt(info, SKIP_BALANCE))
1451                 seq_puts(seq, ",skip_balance");
1452 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1453         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1454                 seq_puts(seq, ",check_int_data");
1455         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1456                 seq_puts(seq, ",check_int");
1457         if (info->check_integrity_print_mask)
1458                 seq_printf(seq, ",check_int_print_mask=%d",
1459                                 info->check_integrity_print_mask);
1460 #endif
1461         if (info->metadata_ratio)
1462                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1463         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1464                 seq_puts(seq, ",fatal_errors=panic");
1465         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1466                 seq_printf(seq, ",commit=%u", info->commit_interval);
1467 #ifdef CONFIG_BTRFS_DEBUG
1468         if (btrfs_test_opt(info, FRAGMENT_DATA))
1469                 seq_puts(seq, ",fragment=data");
1470         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1471                 seq_puts(seq, ",fragment=metadata");
1472 #endif
1473         if (btrfs_test_opt(info, REF_VERIFY))
1474                 seq_puts(seq, ",ref_verify");
1475         seq_printf(seq, ",subvolid=%llu",
1476                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1477         subvol_name = btrfs_get_subvol_name_from_objectid(info,
1478                         BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1479         if (!IS_ERR(subvol_name)) {
1480                 seq_puts(seq, ",subvol=");
1481                 seq_escape(seq, subvol_name, " \t\n\\");
1482                 kfree(subvol_name);
1483         }
1484         return 0;
1485 }
1486
1487 static int btrfs_test_super(struct super_block *s, void *data)
1488 {
1489         struct btrfs_fs_info *p = data;
1490         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1491
1492         return fs_info->fs_devices == p->fs_devices;
1493 }
1494
1495 static int btrfs_set_super(struct super_block *s, void *data)
1496 {
1497         int err = set_anon_super(s, data);
1498         if (!err)
1499                 s->s_fs_info = data;
1500         return err;
1501 }
1502
1503 /*
1504  * subvolumes are identified by ino 256
1505  */
1506 static inline int is_subvolume_inode(struct inode *inode)
1507 {
1508         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1509                 return 1;
1510         return 0;
1511 }
1512
1513 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1514                                    struct vfsmount *mnt)
1515 {
1516         struct dentry *root;
1517         int ret;
1518
1519         if (!subvol_name) {
1520                 if (!subvol_objectid) {
1521                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1522                                                           &subvol_objectid);
1523                         if (ret) {
1524                                 root = ERR_PTR(ret);
1525                                 goto out;
1526                         }
1527                 }
1528                 subvol_name = btrfs_get_subvol_name_from_objectid(
1529                                         btrfs_sb(mnt->mnt_sb), subvol_objectid);
1530                 if (IS_ERR(subvol_name)) {
1531                         root = ERR_CAST(subvol_name);
1532                         subvol_name = NULL;
1533                         goto out;
1534                 }
1535
1536         }
1537
1538         root = mount_subtree(mnt, subvol_name);
1539         /* mount_subtree() drops our reference on the vfsmount. */
1540         mnt = NULL;
1541
1542         if (!IS_ERR(root)) {
1543                 struct super_block *s = root->d_sb;
1544                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1545                 struct inode *root_inode = d_inode(root);
1546                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1547
1548                 ret = 0;
1549                 if (!is_subvolume_inode(root_inode)) {
1550                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1551                                subvol_name);
1552                         ret = -EINVAL;
1553                 }
1554                 if (subvol_objectid && root_objectid != subvol_objectid) {
1555                         /*
1556                          * This will also catch a race condition where a
1557                          * subvolume which was passed by ID is renamed and
1558                          * another subvolume is renamed over the old location.
1559                          */
1560                         btrfs_err(fs_info,
1561                                   "subvol '%s' does not match subvolid %llu",
1562                                   subvol_name, subvol_objectid);
1563                         ret = -EINVAL;
1564                 }
1565                 if (ret) {
1566                         dput(root);
1567                         root = ERR_PTR(ret);
1568                         deactivate_locked_super(s);
1569                 }
1570         }
1571
1572 out:
1573         mntput(mnt);
1574         kfree(subvol_name);
1575         return root;
1576 }
1577
1578 /*
1579  * Find a superblock for the given device / mount point.
1580  *
1581  * Note: This is based on mount_bdev from fs/super.c with a few additions
1582  *       for multiple device setup.  Make sure to keep it in sync.
1583  */
1584 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1585                 int flags, const char *device_name, void *data)
1586 {
1587         struct block_device *bdev = NULL;
1588         struct super_block *s;
1589         struct btrfs_device *device = NULL;
1590         struct btrfs_fs_devices *fs_devices = NULL;
1591         struct btrfs_fs_info *fs_info = NULL;
1592         void *new_sec_opts = NULL;
1593         fmode_t mode = FMODE_READ;
1594         int error = 0;
1595
1596         if (!(flags & SB_RDONLY))
1597                 mode |= FMODE_WRITE;
1598
1599         if (data) {
1600                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1601                 if (error)
1602                         return ERR_PTR(error);
1603         }
1604
1605         /*
1606          * Setup a dummy root and fs_info for test/set super.  This is because
1607          * we don't actually fill this stuff out until open_ctree, but we need
1608          * then open_ctree will properly initialize the file system specific
1609          * settings later.  btrfs_init_fs_info initializes the static elements
1610          * of the fs_info (locks and such) to make cleanup easier if we find a
1611          * superblock with our given fs_devices later on at sget() time.
1612          */
1613         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1614         if (!fs_info) {
1615                 error = -ENOMEM;
1616                 goto error_sec_opts;
1617         }
1618         btrfs_init_fs_info(fs_info);
1619
1620         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1621         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1622         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1623                 error = -ENOMEM;
1624                 goto error_fs_info;
1625         }
1626
1627         mutex_lock(&uuid_mutex);
1628         error = btrfs_parse_device_options(data, mode, fs_type);
1629         if (error) {
1630                 mutex_unlock(&uuid_mutex);
1631                 goto error_fs_info;
1632         }
1633
1634         device = btrfs_scan_one_device(device_name, mode, fs_type);
1635         if (IS_ERR(device)) {
1636                 mutex_unlock(&uuid_mutex);
1637                 error = PTR_ERR(device);
1638                 goto error_fs_info;
1639         }
1640
1641         fs_devices = device->fs_devices;
1642         fs_info->fs_devices = fs_devices;
1643
1644         error = btrfs_open_devices(fs_devices, mode, fs_type);
1645         mutex_unlock(&uuid_mutex);
1646         if (error)
1647                 goto error_fs_info;
1648
1649         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1650                 error = -EACCES;
1651                 goto error_close_devices;
1652         }
1653
1654         bdev = fs_devices->latest_bdev;
1655         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1656                  fs_info);
1657         if (IS_ERR(s)) {
1658                 error = PTR_ERR(s);
1659                 goto error_close_devices;
1660         }
1661
1662         if (s->s_root) {
1663                 btrfs_close_devices(fs_devices);
1664                 btrfs_free_fs_info(fs_info);
1665                 if ((flags ^ s->s_flags) & SB_RDONLY)
1666                         error = -EBUSY;
1667         } else {
1668                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1669                 btrfs_sb(s)->bdev_holder = fs_type;
1670                 if (!strstr(crc32c_impl(), "generic"))
1671                         set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
1672                 error = btrfs_fill_super(s, fs_devices, data);
1673         }
1674         if (!error)
1675                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1676         security_free_mnt_opts(&new_sec_opts);
1677         if (error) {
1678                 deactivate_locked_super(s);
1679                 return ERR_PTR(error);
1680         }
1681
1682         return dget(s->s_root);
1683
1684 error_close_devices:
1685         btrfs_close_devices(fs_devices);
1686 error_fs_info:
1687         btrfs_free_fs_info(fs_info);
1688 error_sec_opts:
1689         security_free_mnt_opts(&new_sec_opts);
1690         return ERR_PTR(error);
1691 }
1692
1693 /*
1694  * Mount function which is called by VFS layer.
1695  *
1696  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1697  * which needs vfsmount* of device's root (/).  This means device's root has to
1698  * be mounted internally in any case.
1699  *
1700  * Operation flow:
1701  *   1. Parse subvol id related options for later use in mount_subvol().
1702  *
1703  *   2. Mount device's root (/) by calling vfs_kern_mount().
1704  *
1705  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1706  *      first place. In order to avoid calling btrfs_mount() again, we use
1707  *      different file_system_type which is not registered to VFS by
1708  *      register_filesystem() (btrfs_root_fs_type). As a result,
1709  *      btrfs_mount_root() is called. The return value will be used by
1710  *      mount_subtree() in mount_subvol().
1711  *
1712  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1713  *      "btrfs subvolume set-default", mount_subvol() is called always.
1714  */
1715 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1716                 const char *device_name, void *data)
1717 {
1718         struct vfsmount *mnt_root;
1719         struct dentry *root;
1720         char *subvol_name = NULL;
1721         u64 subvol_objectid = 0;
1722         int error = 0;
1723
1724         error = btrfs_parse_subvol_options(data, &subvol_name,
1725                                         &subvol_objectid);
1726         if (error) {
1727                 kfree(subvol_name);
1728                 return ERR_PTR(error);
1729         }
1730
1731         /* mount device's root (/) */
1732         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1733         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1734                 if (flags & SB_RDONLY) {
1735                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1736                                 flags & ~SB_RDONLY, device_name, data);
1737                 } else {
1738                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1739                                 flags | SB_RDONLY, device_name, data);
1740                         if (IS_ERR(mnt_root)) {
1741                                 root = ERR_CAST(mnt_root);
1742                                 kfree(subvol_name);
1743                                 goto out;
1744                         }
1745
1746                         down_write(&mnt_root->mnt_sb->s_umount);
1747                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1748                         up_write(&mnt_root->mnt_sb->s_umount);
1749                         if (error < 0) {
1750                                 root = ERR_PTR(error);
1751                                 mntput(mnt_root);
1752                                 kfree(subvol_name);
1753                                 goto out;
1754                         }
1755                 }
1756         }
1757         if (IS_ERR(mnt_root)) {
1758                 root = ERR_CAST(mnt_root);
1759                 kfree(subvol_name);
1760                 goto out;
1761         }
1762
1763         /* mount_subvol() will free subvol_name and mnt_root */
1764         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1765
1766 out:
1767         return root;
1768 }
1769
1770 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1771                                      u32 new_pool_size, u32 old_pool_size)
1772 {
1773         if (new_pool_size == old_pool_size)
1774                 return;
1775
1776         fs_info->thread_pool_size = new_pool_size;
1777
1778         btrfs_info(fs_info, "resize thread pool %d -> %d",
1779                old_pool_size, new_pool_size);
1780
1781         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1782         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1783         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1784         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1785         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1786         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1787                                 new_pool_size);
1788         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1789         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1790         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1791         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1792         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1793                                 new_pool_size);
1794 }
1795
1796 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1797                                        unsigned long old_opts, int flags)
1798 {
1799         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1800             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1801              (flags & SB_RDONLY))) {
1802                 /* wait for any defraggers to finish */
1803                 wait_event(fs_info->transaction_wait,
1804                            (atomic_read(&fs_info->defrag_running) == 0));
1805                 if (flags & SB_RDONLY)
1806                         sync_filesystem(fs_info->sb);
1807         }
1808 }
1809
1810 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1811                                          unsigned long old_opts)
1812 {
1813         /*
1814          * We need to cleanup all defragable inodes if the autodefragment is
1815          * close or the filesystem is read only.
1816          */
1817         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1818             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1819                 btrfs_cleanup_defrag_inodes(fs_info);
1820         }
1821
1822         /* If we toggled discard async */
1823         if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1824             btrfs_test_opt(fs_info, DISCARD_ASYNC))
1825                 btrfs_discard_resume(fs_info);
1826         else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1827                  !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1828                 btrfs_discard_cleanup(fs_info);
1829 }
1830
1831 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1832 {
1833         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1834         struct btrfs_root *root = fs_info->tree_root;
1835         unsigned old_flags = sb->s_flags;
1836         unsigned long old_opts = fs_info->mount_opt;
1837         unsigned long old_compress_type = fs_info->compress_type;
1838         u64 old_max_inline = fs_info->max_inline;
1839         u32 old_thread_pool_size = fs_info->thread_pool_size;
1840         u32 old_metadata_ratio = fs_info->metadata_ratio;
1841         int ret;
1842
1843         sync_filesystem(sb);
1844         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1845
1846         if (data) {
1847                 void *new_sec_opts = NULL;
1848
1849                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1850                 if (!ret)
1851                         ret = security_sb_remount(sb, new_sec_opts);
1852                 security_free_mnt_opts(&new_sec_opts);
1853                 if (ret)
1854                         goto restore;
1855         }
1856
1857         ret = btrfs_parse_options(fs_info, data, *flags);
1858         if (ret)
1859                 goto restore;
1860
1861         btrfs_remount_begin(fs_info, old_opts, *flags);
1862         btrfs_resize_thread_pool(fs_info,
1863                 fs_info->thread_pool_size, old_thread_pool_size);
1864
1865         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1866                 goto out;
1867
1868         if (*flags & SB_RDONLY) {
1869                 /*
1870                  * this also happens on 'umount -rf' or on shutdown, when
1871                  * the filesystem is busy.
1872                  */
1873                 cancel_work_sync(&fs_info->async_reclaim_work);
1874                 cancel_work_sync(&fs_info->async_data_reclaim_work);
1875
1876                 btrfs_discard_cleanup(fs_info);
1877
1878                 /* wait for the uuid_scan task to finish */
1879                 down(&fs_info->uuid_tree_rescan_sem);
1880                 /* avoid complains from lockdep et al. */
1881                 up(&fs_info->uuid_tree_rescan_sem);
1882
1883                 sb->s_flags |= SB_RDONLY;
1884
1885                 /*
1886                  * Setting SB_RDONLY will put the cleaner thread to
1887                  * sleep at the next loop if it's already active.
1888                  * If it's already asleep, we'll leave unused block
1889                  * groups on disk until we're mounted read-write again
1890                  * unless we clean them up here.
1891                  */
1892                 btrfs_delete_unused_bgs(fs_info);
1893
1894                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1895                 btrfs_scrub_cancel(fs_info);
1896                 btrfs_pause_balance(fs_info);
1897
1898                 ret = btrfs_commit_super(fs_info);
1899                 if (ret)
1900                         goto restore;
1901         } else {
1902                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1903                         btrfs_err(fs_info,
1904                                 "Remounting read-write after error is not allowed");
1905                         ret = -EINVAL;
1906                         goto restore;
1907                 }
1908                 if (fs_info->fs_devices->rw_devices == 0) {
1909                         ret = -EACCES;
1910                         goto restore;
1911                 }
1912
1913                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1914                         btrfs_warn(fs_info,
1915                 "too many missing devices, writable remount is not allowed");
1916                         ret = -EACCES;
1917                         goto restore;
1918                 }
1919
1920                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1921                         btrfs_warn(fs_info,
1922                 "mount required to replay tree-log, cannot remount read-write");
1923                         ret = -EINVAL;
1924                         goto restore;
1925                 }
1926
1927                 ret = btrfs_cleanup_fs_roots(fs_info);
1928                 if (ret)
1929                         goto restore;
1930
1931                 /* recover relocation */
1932                 mutex_lock(&fs_info->cleaner_mutex);
1933                 ret = btrfs_recover_relocation(root);
1934                 mutex_unlock(&fs_info->cleaner_mutex);
1935                 if (ret)
1936                         goto restore;
1937
1938                 ret = btrfs_resume_balance_async(fs_info);
1939                 if (ret)
1940                         goto restore;
1941
1942                 ret = btrfs_resume_dev_replace_async(fs_info);
1943                 if (ret) {
1944                         btrfs_warn(fs_info, "failed to resume dev_replace");
1945                         goto restore;
1946                 }
1947
1948                 btrfs_qgroup_rescan_resume(fs_info);
1949
1950                 if (!fs_info->uuid_root) {
1951                         btrfs_info(fs_info, "creating UUID tree");
1952                         ret = btrfs_create_uuid_tree(fs_info);
1953                         if (ret) {
1954                                 btrfs_warn(fs_info,
1955                                            "failed to create the UUID tree %d",
1956                                            ret);
1957                                 goto restore;
1958                         }
1959                 }
1960                 sb->s_flags &= ~SB_RDONLY;
1961
1962                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1963         }
1964 out:
1965         /*
1966          * We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
1967          * since the absence of the flag means it can be toggled off by remount.
1968          */
1969         *flags |= SB_I_VERSION;
1970
1971         wake_up_process(fs_info->transaction_kthread);
1972         btrfs_remount_cleanup(fs_info, old_opts);
1973         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1974
1975         return 0;
1976
1977 restore:
1978         /* We've hit an error - don't reset SB_RDONLY */
1979         if (sb_rdonly(sb))
1980                 old_flags |= SB_RDONLY;
1981         sb->s_flags = old_flags;
1982         fs_info->mount_opt = old_opts;
1983         fs_info->compress_type = old_compress_type;
1984         fs_info->max_inline = old_max_inline;
1985         btrfs_resize_thread_pool(fs_info,
1986                 old_thread_pool_size, fs_info->thread_pool_size);
1987         fs_info->metadata_ratio = old_metadata_ratio;
1988         btrfs_remount_cleanup(fs_info, old_opts);
1989         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1990
1991         return ret;
1992 }
1993
1994 /* Used to sort the devices by max_avail(descending sort) */
1995 static inline int btrfs_cmp_device_free_bytes(const void *dev_info1,
1996                                        const void *dev_info2)
1997 {
1998         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1999             ((struct btrfs_device_info *)dev_info2)->max_avail)
2000                 return -1;
2001         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
2002                  ((struct btrfs_device_info *)dev_info2)->max_avail)
2003                 return 1;
2004         else
2005         return 0;
2006 }
2007
2008 /*
2009  * sort the devices by max_avail, in which max free extent size of each device
2010  * is stored.(Descending Sort)
2011  */
2012 static inline void btrfs_descending_sort_devices(
2013                                         struct btrfs_device_info *devices,
2014                                         size_t nr_devices)
2015 {
2016         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
2017              btrfs_cmp_device_free_bytes, NULL);
2018 }
2019
2020 /*
2021  * The helper to calc the free space on the devices that can be used to store
2022  * file data.
2023  */
2024 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
2025                                               u64 *free_bytes)
2026 {
2027         struct btrfs_device_info *devices_info;
2028         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2029         struct btrfs_device *device;
2030         u64 type;
2031         u64 avail_space;
2032         u64 min_stripe_size;
2033         int num_stripes = 1;
2034         int i = 0, nr_devices;
2035         const struct btrfs_raid_attr *rattr;
2036
2037         /*
2038          * We aren't under the device list lock, so this is racy-ish, but good
2039          * enough for our purposes.
2040          */
2041         nr_devices = fs_info->fs_devices->open_devices;
2042         if (!nr_devices) {
2043                 smp_mb();
2044                 nr_devices = fs_info->fs_devices->open_devices;
2045                 ASSERT(nr_devices);
2046                 if (!nr_devices) {
2047                         *free_bytes = 0;
2048                         return 0;
2049                 }
2050         }
2051
2052         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
2053                                GFP_KERNEL);
2054         if (!devices_info)
2055                 return -ENOMEM;
2056
2057         /* calc min stripe number for data space allocation */
2058         type = btrfs_data_alloc_profile(fs_info);
2059         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
2060
2061         if (type & BTRFS_BLOCK_GROUP_RAID0)
2062                 num_stripes = nr_devices;
2063         else if (type & BTRFS_BLOCK_GROUP_RAID1)
2064                 num_stripes = 2;
2065         else if (type & BTRFS_BLOCK_GROUP_RAID1C3)
2066                 num_stripes = 3;
2067         else if (type & BTRFS_BLOCK_GROUP_RAID1C4)
2068                 num_stripes = 4;
2069         else if (type & BTRFS_BLOCK_GROUP_RAID10)
2070                 num_stripes = 4;
2071
2072         /* Adjust for more than 1 stripe per device */
2073         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
2074
2075         rcu_read_lock();
2076         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
2077                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
2078                                                 &device->dev_state) ||
2079                     !device->bdev ||
2080                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
2081                         continue;
2082
2083                 if (i >= nr_devices)
2084                         break;
2085
2086                 avail_space = device->total_bytes - device->bytes_used;
2087
2088                 /* align with stripe_len */
2089                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
2090
2091                 /*
2092                  * In order to avoid overwriting the superblock on the drive,
2093                  * btrfs starts at an offset of at least 1MB when doing chunk
2094                  * allocation.
2095                  *
2096                  * This ensures we have at least min_stripe_size free space
2097                  * after excluding 1MB.
2098                  */
2099                 if (avail_space <= SZ_1M + min_stripe_size)
2100                         continue;
2101
2102                 avail_space -= SZ_1M;
2103
2104                 devices_info[i].dev = device;
2105                 devices_info[i].max_avail = avail_space;
2106
2107                 i++;
2108         }
2109         rcu_read_unlock();
2110
2111         nr_devices = i;
2112
2113         btrfs_descending_sort_devices(devices_info, nr_devices);
2114
2115         i = nr_devices - 1;
2116         avail_space = 0;
2117         while (nr_devices >= rattr->devs_min) {
2118                 num_stripes = min(num_stripes, nr_devices);
2119
2120                 if (devices_info[i].max_avail >= min_stripe_size) {
2121                         int j;
2122                         u64 alloc_size;
2123
2124                         avail_space += devices_info[i].max_avail * num_stripes;
2125                         alloc_size = devices_info[i].max_avail;
2126                         for (j = i + 1 - num_stripes; j <= i; j++)
2127                                 devices_info[j].max_avail -= alloc_size;
2128                 }
2129                 i--;
2130                 nr_devices--;
2131         }
2132
2133         kfree(devices_info);
2134         *free_bytes = avail_space;
2135         return 0;
2136 }
2137
2138 /*
2139  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2140  *
2141  * If there's a redundant raid level at DATA block groups, use the respective
2142  * multiplier to scale the sizes.
2143  *
2144  * Unused device space usage is based on simulating the chunk allocator
2145  * algorithm that respects the device sizes and order of allocations.  This is
2146  * a close approximation of the actual use but there are other factors that may
2147  * change the result (like a new metadata chunk).
2148  *
2149  * If metadata is exhausted, f_bavail will be 0.
2150  */
2151 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2152 {
2153         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2154         struct btrfs_super_block *disk_super = fs_info->super_copy;
2155         struct btrfs_space_info *found;
2156         u64 total_used = 0;
2157         u64 total_free_data = 0;
2158         u64 total_free_meta = 0;
2159         int bits = dentry->d_sb->s_blocksize_bits;
2160         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2161         unsigned factor = 1;
2162         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2163         int ret;
2164         u64 thresh = 0;
2165         int mixed = 0;
2166
2167         list_for_each_entry(found, &fs_info->space_info, list) {
2168                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2169                         int i;
2170
2171                         total_free_data += found->disk_total - found->disk_used;
2172                         total_free_data -=
2173                                 btrfs_account_ro_block_groups_free_space(found);
2174
2175                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2176                                 if (!list_empty(&found->block_groups[i]))
2177                                         factor = btrfs_bg_type_to_factor(
2178                                                 btrfs_raid_array[i].bg_flag);
2179                         }
2180                 }
2181
2182                 /*
2183                  * Metadata in mixed block goup profiles are accounted in data
2184                  */
2185                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2186                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2187                                 mixed = 1;
2188                         else
2189                                 total_free_meta += found->disk_total -
2190                                         found->disk_used;
2191                 }
2192
2193                 total_used += found->disk_used;
2194         }
2195
2196         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2197         buf->f_blocks >>= bits;
2198         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2199
2200         /* Account global block reserve as used, it's in logical size already */
2201         spin_lock(&block_rsv->lock);
2202         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2203         if (buf->f_bfree >= block_rsv->size >> bits)
2204                 buf->f_bfree -= block_rsv->size >> bits;
2205         else
2206                 buf->f_bfree = 0;
2207         spin_unlock(&block_rsv->lock);
2208
2209         buf->f_bavail = div_u64(total_free_data, factor);
2210         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2211         if (ret)
2212                 return ret;
2213         buf->f_bavail += div_u64(total_free_data, factor);
2214         buf->f_bavail = buf->f_bavail >> bits;
2215
2216         /*
2217          * We calculate the remaining metadata space minus global reserve. If
2218          * this is (supposedly) smaller than zero, there's no space. But this
2219          * does not hold in practice, the exhausted state happens where's still
2220          * some positive delta. So we apply some guesswork and compare the
2221          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2222          *
2223          * We probably cannot calculate the exact threshold value because this
2224          * depends on the internal reservations requested by various
2225          * operations, so some operations that consume a few metadata will
2226          * succeed even if the Avail is zero. But this is better than the other
2227          * way around.
2228          */
2229         thresh = SZ_4M;
2230
2231         /*
2232          * We only want to claim there's no available space if we can no longer
2233          * allocate chunks for our metadata profile and our global reserve will
2234          * not fit in the free metadata space.  If we aren't ->full then we
2235          * still can allocate chunks and thus are fine using the currently
2236          * calculated f_bavail.
2237          */
2238         if (!mixed && block_rsv->space_info->full &&
2239             total_free_meta - thresh < block_rsv->size)
2240                 buf->f_bavail = 0;
2241
2242         buf->f_type = BTRFS_SUPER_MAGIC;
2243         buf->f_bsize = dentry->d_sb->s_blocksize;
2244         buf->f_namelen = BTRFS_NAME_LEN;
2245
2246         /* We treat it as constant endianness (it doesn't matter _which_)
2247            because we want the fsid to come out the same whether mounted
2248            on a big-endian or little-endian host */
2249         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2250         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2251         /* Mask in the root object ID too, to disambiguate subvols */
2252         buf->f_fsid.val[0] ^=
2253                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2254         buf->f_fsid.val[1] ^=
2255                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2256
2257         return 0;
2258 }
2259
2260 static void btrfs_kill_super(struct super_block *sb)
2261 {
2262         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2263         kill_anon_super(sb);
2264         btrfs_free_fs_info(fs_info);
2265 }
2266
2267 static struct file_system_type btrfs_fs_type = {
2268         .owner          = THIS_MODULE,
2269         .name           = "btrfs",
2270         .mount          = btrfs_mount,
2271         .kill_sb        = btrfs_kill_super,
2272         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2273 };
2274
2275 static struct file_system_type btrfs_root_fs_type = {
2276         .owner          = THIS_MODULE,
2277         .name           = "btrfs",
2278         .mount          = btrfs_mount_root,
2279         .kill_sb        = btrfs_kill_super,
2280         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2281 };
2282
2283 MODULE_ALIAS_FS("btrfs");
2284
2285 static int btrfs_control_open(struct inode *inode, struct file *file)
2286 {
2287         /*
2288          * The control file's private_data is used to hold the
2289          * transaction when it is started and is used to keep
2290          * track of whether a transaction is already in progress.
2291          */
2292         file->private_data = NULL;
2293         return 0;
2294 }
2295
2296 /*
2297  * Used by /dev/btrfs-control for devices ioctls.
2298  */
2299 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2300                                 unsigned long arg)
2301 {
2302         struct btrfs_ioctl_vol_args *vol;
2303         struct btrfs_device *device = NULL;
2304         int ret = -ENOTTY;
2305
2306         if (!capable(CAP_SYS_ADMIN))
2307                 return -EPERM;
2308
2309         vol = memdup_user((void __user *)arg, sizeof(*vol));
2310         if (IS_ERR(vol))
2311                 return PTR_ERR(vol);
2312         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2313
2314         switch (cmd) {
2315         case BTRFS_IOC_SCAN_DEV:
2316                 mutex_lock(&uuid_mutex);
2317                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2318                                                &btrfs_root_fs_type);
2319                 ret = PTR_ERR_OR_ZERO(device);
2320                 mutex_unlock(&uuid_mutex);
2321                 break;
2322         case BTRFS_IOC_FORGET_DEV:
2323                 ret = btrfs_forget_devices(vol->name);
2324                 break;
2325         case BTRFS_IOC_DEVICES_READY:
2326                 mutex_lock(&uuid_mutex);
2327                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2328                                                &btrfs_root_fs_type);
2329                 if (IS_ERR(device)) {
2330                         mutex_unlock(&uuid_mutex);
2331                         ret = PTR_ERR(device);
2332                         break;
2333                 }
2334                 ret = !(device->fs_devices->num_devices ==
2335                         device->fs_devices->total_devices);
2336                 mutex_unlock(&uuid_mutex);
2337                 break;
2338         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2339                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2340                 break;
2341         }
2342
2343         kfree(vol);
2344         return ret;
2345 }
2346
2347 static int btrfs_freeze(struct super_block *sb)
2348 {
2349         struct btrfs_trans_handle *trans;
2350         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2351         struct btrfs_root *root = fs_info->tree_root;
2352
2353         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2354         /*
2355          * We don't need a barrier here, we'll wait for any transaction that
2356          * could be in progress on other threads (and do delayed iputs that
2357          * we want to avoid on a frozen filesystem), or do the commit
2358          * ourselves.
2359          */
2360         trans = btrfs_attach_transaction_barrier(root);
2361         if (IS_ERR(trans)) {
2362                 /* no transaction, don't bother */
2363                 if (PTR_ERR(trans) == -ENOENT)
2364                         return 0;
2365                 return PTR_ERR(trans);
2366         }
2367         return btrfs_commit_transaction(trans);
2368 }
2369
2370 static int btrfs_unfreeze(struct super_block *sb)
2371 {
2372         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2373
2374         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2375         return 0;
2376 }
2377
2378 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2379 {
2380         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2381         struct btrfs_device *dev, *first_dev = NULL;
2382
2383         /*
2384          * Lightweight locking of the devices. We should not need
2385          * device_list_mutex here as we only read the device data and the list
2386          * is protected by RCU.  Even if a device is deleted during the list
2387          * traversals, we'll get valid data, the freeing callback will wait at
2388          * least until the rcu_read_unlock.
2389          */
2390         rcu_read_lock();
2391         list_for_each_entry_rcu(dev, &fs_info->fs_devices->devices, dev_list) {
2392                 if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
2393                         continue;
2394                 if (!dev->name)
2395                         continue;
2396                 if (!first_dev || dev->devid < first_dev->devid)
2397                         first_dev = dev;
2398         }
2399
2400         if (first_dev)
2401                 seq_escape(m, rcu_str_deref(first_dev->name), " \t\n\\");
2402         else
2403                 WARN_ON(1);
2404         rcu_read_unlock();
2405         return 0;
2406 }
2407
2408 static const struct super_operations btrfs_super_ops = {
2409         .drop_inode     = btrfs_drop_inode,
2410         .evict_inode    = btrfs_evict_inode,
2411         .put_super      = btrfs_put_super,
2412         .sync_fs        = btrfs_sync_fs,
2413         .show_options   = btrfs_show_options,
2414         .show_devname   = btrfs_show_devname,
2415         .alloc_inode    = btrfs_alloc_inode,
2416         .destroy_inode  = btrfs_destroy_inode,
2417         .free_inode     = btrfs_free_inode,
2418         .statfs         = btrfs_statfs,
2419         .remount_fs     = btrfs_remount,
2420         .freeze_fs      = btrfs_freeze,
2421         .unfreeze_fs    = btrfs_unfreeze,
2422 };
2423
2424 static const struct file_operations btrfs_ctl_fops = {
2425         .open = btrfs_control_open,
2426         .unlocked_ioctl  = btrfs_control_ioctl,
2427         .compat_ioctl = compat_ptr_ioctl,
2428         .owner   = THIS_MODULE,
2429         .llseek = noop_llseek,
2430 };
2431
2432 static struct miscdevice btrfs_misc = {
2433         .minor          = BTRFS_MINOR,
2434         .name           = "btrfs-control",
2435         .fops           = &btrfs_ctl_fops
2436 };
2437
2438 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2439 MODULE_ALIAS("devname:btrfs-control");
2440
2441 static int __init btrfs_interface_init(void)
2442 {
2443         return misc_register(&btrfs_misc);
2444 }
2445
2446 static __cold void btrfs_interface_exit(void)
2447 {
2448         misc_deregister(&btrfs_misc);
2449 }
2450
2451 static void __init btrfs_print_mod_info(void)
2452 {
2453         static const char options[] = ""
2454 #ifdef CONFIG_BTRFS_DEBUG
2455                         ", debug=on"
2456 #endif
2457 #ifdef CONFIG_BTRFS_ASSERT
2458                         ", assert=on"
2459 #endif
2460 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2461                         ", integrity-checker=on"
2462 #endif
2463 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2464                         ", ref-verify=on"
2465 #endif
2466                         ;
2467         pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
2468 }
2469
2470 static int __init init_btrfs_fs(void)
2471 {
2472         int err;
2473
2474         btrfs_props_init();
2475
2476         err = btrfs_init_sysfs();
2477         if (err)
2478                 return err;
2479
2480         btrfs_init_compress();
2481
2482         err = btrfs_init_cachep();
2483         if (err)
2484                 goto free_compress;
2485
2486         err = extent_io_init();
2487         if (err)
2488                 goto free_cachep;
2489
2490         err = extent_state_cache_init();
2491         if (err)
2492                 goto free_extent_io;
2493
2494         err = extent_map_init();
2495         if (err)
2496                 goto free_extent_state_cache;
2497
2498         err = ordered_data_init();
2499         if (err)
2500                 goto free_extent_map;
2501
2502         err = btrfs_delayed_inode_init();
2503         if (err)
2504                 goto free_ordered_data;
2505
2506         err = btrfs_auto_defrag_init();
2507         if (err)
2508                 goto free_delayed_inode;
2509
2510         err = btrfs_delayed_ref_init();
2511         if (err)
2512                 goto free_auto_defrag;
2513
2514         err = btrfs_prelim_ref_init();
2515         if (err)
2516                 goto free_delayed_ref;
2517
2518         err = btrfs_end_io_wq_init();
2519         if (err)
2520                 goto free_prelim_ref;
2521
2522         err = btrfs_interface_init();
2523         if (err)
2524                 goto free_end_io_wq;
2525
2526         btrfs_init_lockdep();
2527
2528         btrfs_print_mod_info();
2529
2530         err = btrfs_run_sanity_tests();
2531         if (err)
2532                 goto unregister_ioctl;
2533
2534         err = register_filesystem(&btrfs_fs_type);
2535         if (err)
2536                 goto unregister_ioctl;
2537
2538         return 0;
2539
2540 unregister_ioctl:
2541         btrfs_interface_exit();
2542 free_end_io_wq:
2543         btrfs_end_io_wq_exit();
2544 free_prelim_ref:
2545         btrfs_prelim_ref_exit();
2546 free_delayed_ref:
2547         btrfs_delayed_ref_exit();
2548 free_auto_defrag:
2549         btrfs_auto_defrag_exit();
2550 free_delayed_inode:
2551         btrfs_delayed_inode_exit();
2552 free_ordered_data:
2553         ordered_data_exit();
2554 free_extent_map:
2555         extent_map_exit();
2556 free_extent_state_cache:
2557         extent_state_cache_exit();
2558 free_extent_io:
2559         extent_io_exit();
2560 free_cachep:
2561         btrfs_destroy_cachep();
2562 free_compress:
2563         btrfs_exit_compress();
2564         btrfs_exit_sysfs();
2565
2566         return err;
2567 }
2568
2569 static void __exit exit_btrfs_fs(void)
2570 {
2571         btrfs_destroy_cachep();
2572         btrfs_delayed_ref_exit();
2573         btrfs_auto_defrag_exit();
2574         btrfs_delayed_inode_exit();
2575         btrfs_prelim_ref_exit();
2576         ordered_data_exit();
2577         extent_map_exit();
2578         extent_state_cache_exit();
2579         extent_io_exit();
2580         btrfs_interface_exit();
2581         btrfs_end_io_wq_exit();
2582         unregister_filesystem(&btrfs_fs_type);
2583         btrfs_exit_sysfs();
2584         btrfs_cleanup_fs_uuids();
2585         btrfs_exit_compress();
2586 }
2587
2588 late_initcall(init_btrfs_fs);
2589 module_exit(exit_btrfs_fs)
2590
2591 MODULE_LICENSE("GPL");
2592 MODULE_SOFTDEP("pre: crc32c");
2593 MODULE_SOFTDEP("pre: xxhash64");
2594 MODULE_SOFTDEP("pre: sha256");
2595 MODULE_SOFTDEP("pre: blake2b-256");