fs/btrfs/super.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/blkdev.h>
   7 #include <linux/module.h>
   8 #include <linux/fs.h>
   9 #include <linux/pagemap.h>
  10 #include <linux/highmem.h>
  11 #include <linux/time.h>
  12 #include <linux/init.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/string.h>
  15 #include <linux/backing-dev.h>
  16 #include <linux/mount.h>
  17 #include <linux/writeback.h>
  18 #include <linux/statfs.h>
  19 #include <linux/compat.h>
  20 #include <linux/parser.h>
  21 #include <linux/ctype.h>
  22 #include <linux/namei.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/magic.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/crc32c.h>
  28 #include <linux/btrfs.h>
  29 #include <linux/security.h>
  30 #include "messages.h"
  31 #include "delayed-inode.h"
  32 #include "ctree.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "btrfs_inode.h"
  36 #include "print-tree.h"
  37 #include "props.h"
  38 #include "xattr.h"
  39 #include "bio.h"
  40 #include "export.h"
  41 #include "compression.h"
  42 #include "rcu-string.h"
  43 #include "dev-replace.h"
  44 #include "free-space-cache.h"
  45 #include "backref.h"
  46 #include "space-info.h"
  47 #include "sysfs.h"
  48 #include "zoned.h"
  49 #include "tests/btrfs-tests.h"
  50 #include "block-group.h"
  51 #include "discard.h"
  52 #include "qgroup.h"
  53 #include "raid56.h"
  54 #include "fs.h"
  55 #include "accessors.h"
  56 #include "defrag.h"
  57 #include "dir-item.h"
  58 #include "ioctl.h"
  59 #include "scrub.h"
  60 #include "verity.h"
  61 #include "super.h"
  62 #include "extent-tree.h"
  63 #define CREATE_TRACE_POINTS
  64 #include <trace/events/btrfs.h>
  65
  66 static const struct super_operations btrfs_super_ops;
  67
  68 /*
  69  * Types for mounting the default subvolume and a subvolume explicitly
  70  * requested by subvol=/path. That way the callchain is straightforward and we
  71  * don't have to play tricks with the mount options and recursive calls to
  72  * btrfs_mount.
  73  *
  74  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
  75  */
  76 static struct file_system_type btrfs_fs_type;
  77 static struct file_system_type btrfs_root_fs_type;
  78
  79 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  80
  81 static void btrfs_put_super(struct super_block *sb)
  82 {
  83         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
  84
  85         btrfs_info(fs_info, "last unmount of filesystem %pU", fs_info->fs_devices->fsid);
  86         close_ctree(fs_info);
  87 }
  88
  89 enum {
  90         Opt_acl, Opt_noacl,
  91         Opt_clear_cache,
  92         Opt_commit_interval,
  93         Opt_compress,
  94         Opt_compress_force,
  95         Opt_compress_force_type,
  96         Opt_compress_type,
  97         Opt_degraded,
  98         Opt_device,
  99         Opt_fatal_errors,
 100         Opt_flushoncommit, Opt_noflushoncommit,
 101         Opt_max_inline,
 102         Opt_barrier, Opt_nobarrier,
 103         Opt_datacow, Opt_nodatacow,
 104         Opt_datasum, Opt_nodatasum,
 105         Opt_defrag, Opt_nodefrag,
 106         Opt_discard, Opt_nodiscard,
 107         Opt_discard_mode,
 108         Opt_norecovery,
 109         Opt_ratio,
 110         Opt_rescan_uuid_tree,
 111         Opt_skip_balance,
 112         Opt_space_cache, Opt_no_space_cache,
 113         Opt_space_cache_version,
 114         Opt_ssd, Opt_nossd,
 115         Opt_ssd_spread, Opt_nossd_spread,
 116         Opt_subvol,
 117         Opt_subvol_empty,
 118         Opt_subvolid,
 119         Opt_thread_pool,
 120         Opt_treelog, Opt_notreelog,
 121         Opt_user_subvol_rm_allowed,
 122
 123         /* Rescue options */
 124         Opt_rescue,
 125         Opt_usebackuproot,
 126         Opt_nologreplay,
 127         Opt_ignorebadroots,
 128         Opt_ignoredatacsums,
 129         Opt_rescue_all,
 130
 131         /* Deprecated options */
 132         Opt_recovery,
 133         Opt_inode_cache, Opt_noinode_cache,
 134
 135         /* Debugging options */
 136         Opt_enospc_debug, Opt_noenospc_debug,
 137 #ifdef CONFIG_BTRFS_DEBUG
 138         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 139 #endif
 140 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 141         Opt_ref_verify,
 142 #endif
 143         Opt_err,
 144 };
 145
 146 static const match_table_t tokens = {
 147         {Opt_acl, "acl"},
 148         {Opt_noacl, "noacl"},
 149         {Opt_clear_cache, "clear_cache"},
 150         {Opt_commit_interval, "commit=%u"},
 151         {Opt_compress, "compress"},
 152         {Opt_compress_type, "compress=%s"},
 153         {Opt_compress_force, "compress-force"},
 154         {Opt_compress_force_type, "compress-force=%s"},
 155         {Opt_degraded, "degraded"},
 156         {Opt_device, "device=%s"},
 157         {Opt_fatal_errors, "fatal_errors=%s"},
 158         {Opt_flushoncommit, "flushoncommit"},
 159         {Opt_noflushoncommit, "noflushoncommit"},
 160         {Opt_inode_cache, "inode_cache"},
 161         {Opt_noinode_cache, "noinode_cache"},
 162         {Opt_max_inline, "max_inline=%s"},
 163         {Opt_barrier, "barrier"},
 164         {Opt_nobarrier, "nobarrier"},
 165         {Opt_datacow, "datacow"},
 166         {Opt_nodatacow, "nodatacow"},
 167         {Opt_datasum, "datasum"},
 168         {Opt_nodatasum, "nodatasum"},
 169         {Opt_defrag, "autodefrag"},
 170         {Opt_nodefrag, "noautodefrag"},
 171         {Opt_discard, "discard"},
 172         {Opt_discard_mode, "discard=%s"},
 173         {Opt_nodiscard, "nodiscard"},
 174         {Opt_norecovery, "norecovery"},
 175         {Opt_ratio, "metadata_ratio=%u"},
 176         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 177         {Opt_skip_balance, "skip_balance"},
 178         {Opt_space_cache, "space_cache"},
 179         {Opt_no_space_cache, "nospace_cache"},
 180         {Opt_space_cache_version, "space_cache=%s"},
 181         {Opt_ssd, "ssd"},
 182         {Opt_nossd, "nossd"},
 183         {Opt_ssd_spread, "ssd_spread"},
 184         {Opt_nossd_spread, "nossd_spread"},
 185         {Opt_subvol, "subvol=%s"},
 186         {Opt_subvol_empty, "subvol="},
 187         {Opt_subvolid, "subvolid=%s"},
 188         {Opt_thread_pool, "thread_pool=%u"},
 189         {Opt_treelog, "treelog"},
 190         {Opt_notreelog, "notreelog"},
 191         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 192
 193         /* Rescue options */
 194         {Opt_rescue, "rescue=%s"},
 195         /* Deprecated, with alias rescue=nologreplay */
 196         {Opt_nologreplay, "nologreplay"},
 197         /* Deprecated, with alias rescue=usebackuproot */
 198         {Opt_usebackuproot, "usebackuproot"},
 199
 200         /* Deprecated options */
 201         {Opt_recovery, "recovery"},
 202
 203         /* Debugging options */
 204         {Opt_enospc_debug, "enospc_debug"},
 205         {Opt_noenospc_debug, "noenospc_debug"},
 206 #ifdef CONFIG_BTRFS_DEBUG
 207         {Opt_fragment_data, "fragment=data"},
 208         {Opt_fragment_metadata, "fragment=metadata"},
 209         {Opt_fragment_all, "fragment=all"},
 210 #endif
 211 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 212         {Opt_ref_verify, "ref_verify"},
 213 #endif
 214         {Opt_err, NULL},
 215 };
 216
 217 static const match_table_t rescue_tokens = {
 218         {Opt_usebackuproot, "usebackuproot"},
 219         {Opt_nologreplay, "nologreplay"},
 220         {Opt_ignorebadroots, "ignorebadroots"},
 221         {Opt_ignorebadroots, "ibadroots"},
 222         {Opt_ignoredatacsums, "ignoredatacsums"},
 223         {Opt_ignoredatacsums, "idatacsums"},
 224         {Opt_rescue_all, "all"},
 225         {Opt_err, NULL},
 226 };
 227
 228 static bool check_ro_option(struct btrfs_fs_info *fs_info, unsigned long opt,
 229                             const char *opt_name)
 230 {
 231         if (fs_info->mount_opt & opt) {
 232                 btrfs_err(fs_info, "%s must be used with ro mount option",
 233                           opt_name);
 234                 return true;
 235         }
 236         return false;
 237 }
 238
 239 static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
 240 {
 241         char *opts;
 242         char *orig;
 243         char *p;
 244         substring_t args[MAX_OPT_ARGS];
 245         int ret = 0;
 246
 247         opts = kstrdup(options, GFP_KERNEL);
 248         if (!opts)
 249                 return -ENOMEM;
 250         orig = opts;
 251
 252         while ((p = strsep(&opts, ":")) != NULL) {
 253                 int token;
 254
 255                 if (!*p)
 256                         continue;
 257                 token = match_token(p, rescue_tokens, args);
 258                 switch (token){
 259                 case Opt_usebackuproot:
 260                         btrfs_info(info,
 261                                    "trying to use backup root at mount time");
 262                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 263                         break;
 264                 case Opt_nologreplay:
 265                         btrfs_set_and_info(info, NOLOGREPLAY,
 266                                            "disabling log replay at mount time");
 267                         break;
 268                 case Opt_ignorebadroots:
 269                         btrfs_set_and_info(info, IGNOREBADROOTS,
 270                                            "ignoring bad roots");
 271                         break;
 272                 case Opt_ignoredatacsums:
 273                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 274                                            "ignoring data csums");
 275                         break;
 276                 case Opt_rescue_all:
 277                         btrfs_info(info, "enabling all of the rescue options");
 278                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 279                                            "ignoring data csums");
 280                         btrfs_set_and_info(info, IGNOREBADROOTS,
 281                                            "ignoring bad roots");
 282                         btrfs_set_and_info(info, NOLOGREPLAY,
 283                                            "disabling log replay at mount time");
 284                         break;
 285                 case Opt_err:
 286                         btrfs_info(info, "unrecognized rescue option '%s'", p);
 287                         ret = -EINVAL;
 288                         goto out;
 289                 default:
 290                         break;
 291                 }
 292
 293         }
 294 out:
 295         kfree(orig);
 296         return ret;
 297 }
 298
 299 /*
 300  * Regular mount options parser.  Everything that is needed only when
 301  * reading in a new superblock is parsed here.
 302  * XXX JDM: This needs to be cleaned up for remount.
 303  */
 304 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 305                         unsigned long new_flags)
 306 {
 307         substring_t args[MAX_OPT_ARGS];
 308         char *p, *num;
 309         int intarg;
 310         int ret = 0;
 311         char *compress_type;
 312         bool compress_force = false;
 313         enum btrfs_compression_type saved_compress_type;
 314         int saved_compress_level;
 315         bool saved_compress_force;
 316         int no_compress = 0;
 317         const bool remounting = test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state);
 318
 319         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 320                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 321         else if (btrfs_free_space_cache_v1_active(info)) {
 322                 if (btrfs_is_zoned(info)) {
 323                         btrfs_info(info,
 324                         "zoned: clearing existing space cache");
 325                         btrfs_set_super_cache_generation(info->super_copy, 0);
 326                 } else {
 327                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 328                 }
 329         }
 330
 331         /*
 332          * Even the options are empty, we still need to do extra check
 333          * against new flags
 334          */
 335         if (!options)
 336                 goto check;
 337
 338         while ((p = strsep(&options, ",")) != NULL) {
 339                 int token;
 340                 if (!*p)
 341                         continue;
 342
 343                 token = match_token(p, tokens, args);
 344                 switch (token) {
 345                 case Opt_degraded:
 346                         btrfs_info(info, "allowing degraded mounts");
 347                         btrfs_set_opt(info->mount_opt, DEGRADED);
 348                         break;
 349                 case Opt_subvol:
 350                 case Opt_subvol_empty:
 351                 case Opt_subvolid:
 352                 case Opt_device:
 353                         /*
 354                          * These are parsed by btrfs_parse_subvol_options or
 355                          * btrfs_parse_device_options and can be ignored here.
 356                          */
 357                         break;
 358                 case Opt_nodatasum:
 359                         btrfs_set_and_info(info, NODATASUM,
 360                                            "setting nodatasum");
 361                         break;
 362                 case Opt_datasum:
 363                         if (btrfs_test_opt(info, NODATASUM)) {
 364                                 if (btrfs_test_opt(info, NODATACOW))
 365                                         btrfs_info(info,
 366                                                    "setting datasum, datacow enabled");
 367                                 else
 368                                         btrfs_info(info, "setting datasum");
 369                         }
 370                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 371                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 372                         break;
 373                 case Opt_nodatacow:
 374                         if (!btrfs_test_opt(info, NODATACOW)) {
 375                                 if (!btrfs_test_opt(info, COMPRESS) ||
 376                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 377                                         btrfs_info(info,
 378                                                    "setting nodatacow, compression disabled");
 379                                 } else {
 380                                         btrfs_info(info, "setting nodatacow");
 381                                 }
 382                         }
 383                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 384                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 385                         btrfs_set_opt(info->mount_opt, NODATACOW);
 386                         btrfs_set_opt(info->mount_opt, NODATASUM);
 387                         break;
 388                 case Opt_datacow:
 389                         btrfs_clear_and_info(info, NODATACOW,
 390                                              "setting datacow");
 391                         break;
 392                 case Opt_compress_force:
 393                 case Opt_compress_force_type:
 394                         compress_force = true;
 395                         fallthrough;
 396                 case Opt_compress:
 397                 case Opt_compress_type:
 398                         saved_compress_type = btrfs_test_opt(info,
 399                                                              COMPRESS) ?
 400                                 info->compress_type : BTRFS_COMPRESS_NONE;
 401                         saved_compress_force =
 402                                 btrfs_test_opt(info, FORCE_COMPRESS);
 403                         saved_compress_level = info->compress_level;
 404                         if (token == Opt_compress ||
 405                             token == Opt_compress_force ||
 406                             strncmp(args[0].from, "zlib", 4) == 0) {
 407                                 compress_type = "zlib";
 408
 409                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 410                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 411                                 /*
 412                                  * args[0] contains uninitialized data since
 413                                  * for these tokens we don't expect any
 414                                  * parameter.
 415                                  */
 416                                 if (token != Opt_compress &&
 417                                     token != Opt_compress_force)
 418                                         info->compress_level =
 419                                           btrfs_compress_str2level(
 420                                                         BTRFS_COMPRESS_ZLIB,
 421                                                         args[0].from + 4);
 422                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 423                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 424                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 425                                 no_compress = 0;
 426                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 427                                 compress_type = "lzo";
 428                                 info->compress_type = BTRFS_COMPRESS_LZO;
 429                                 info->compress_level = 0;
 430                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 431                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 432                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 433                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 434                                 no_compress = 0;
 435                         } else if (strncmp(args[0].from, "zstd", 4) == 0) {
 436                                 compress_type = "zstd";
 437                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 438                                 info->compress_level =
 439                                         btrfs_compress_str2level(
 440                                                          BTRFS_COMPRESS_ZSTD,
 441                                                          args[0].from + 4);
 442                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 443                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 444                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 445                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 446                                 no_compress = 0;
 447                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 448                                 compress_type = "no";
 449                                 info->compress_level = 0;
 450                                 info->compress_type = 0;
 451                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 452                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 453                                 compress_force = false;
 454                                 no_compress++;
 455                         } else {
 456                                 btrfs_err(info, "unrecognized compression value %s",
 457                                           args[0].from);
 458                                 ret = -EINVAL;
 459                                 goto out;
 460                         }
 461
 462                         if (compress_force) {
 463                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 464                         } else {
 465                                 /*
 466                                  * If we remount from compress-force=xxx to
 467                                  * compress=xxx, we need clear FORCE_COMPRESS
 468                                  * flag, otherwise, there is no way for users
 469                                  * to disable forcible compression separately.
 470                                  */
 471                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 472                         }
 473                         if (no_compress == 1) {
 474                                 btrfs_info(info, "use no compression");
 475                         } else if ((info->compress_type != saved_compress_type) ||
 476                                    (compress_force != saved_compress_force) ||
 477                                    (info->compress_level != saved_compress_level)) {
 478                                 btrfs_info(info, "%s %s compression, level %d",
 479                                            (compress_force) ? "force" : "use",
 480                                            compress_type, info->compress_level);
 481                         }
 482                         compress_force = false;
 483                         break;
 484                 case Opt_ssd:
 485                         btrfs_set_and_info(info, SSD,
 486                                            "enabling ssd optimizations");
 487                         btrfs_clear_opt(info->mount_opt, NOSSD);
 488                         break;
 489                 case Opt_ssd_spread:
 490                         btrfs_set_and_info(info, SSD,
 491                                            "enabling ssd optimizations");
 492                         btrfs_set_and_info(info, SSD_SPREAD,
 493                                            "using spread ssd allocation scheme");
 494                         btrfs_clear_opt(info->mount_opt, NOSSD);
 495                         break;
 496                 case Opt_nossd:
 497                         btrfs_set_opt(info->mount_opt, NOSSD);
 498                         btrfs_clear_and_info(info, SSD,
 499                                              "not using ssd optimizations");
 500                         fallthrough;
 501                 case Opt_nossd_spread:
 502                         btrfs_clear_and_info(info, SSD_SPREAD,
 503                                              "not using spread ssd allocation scheme");
 504                         break;
 505                 case Opt_barrier:
 506                         btrfs_clear_and_info(info, NOBARRIER,
 507                                              "turning on barriers");
 508                         break;
 509                 case Opt_nobarrier:
 510                         btrfs_set_and_info(info, NOBARRIER,
 511                                            "turning off barriers");
 512                         break;
 513                 case Opt_thread_pool:
 514                         ret = match_int(&args[0], &intarg);
 515                         if (ret) {
 516                                 btrfs_err(info, "unrecognized thread_pool value %s",
 517                                           args[0].from);
 518                                 goto out;
 519                         } else if (intarg == 0) {
 520                                 btrfs_err(info, "invalid value 0 for thread_pool");
 521                                 ret = -EINVAL;
 522                                 goto out;
 523                         }
 524                         info->thread_pool_size = intarg;
 525                         break;
 526                 case Opt_max_inline:
 527                         num = match_strdup(&args[0]);
 528                         if (num) {
 529                                 info->max_inline = memparse(num, NULL);
 530                                 kfree(num);
 531
 532                                 if (info->max_inline) {
 533                                         info->max_inline = min_t(u64,
 534                                                 info->max_inline,
 535                                                 info->sectorsize);
 536                                 }
 537                                 btrfs_info(info, "max_inline at %llu",
 538                                            info->max_inline);
 539                         } else {
 540                                 ret = -ENOMEM;
 541                                 goto out;
 542                         }
 543                         break;
 544                 case Opt_acl:
 545 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 546                         info->sb->s_flags |= SB_POSIXACL;
 547                         break;
 548 #else
 549                         btrfs_err(info, "support for ACL not compiled in!");
 550                         ret = -EINVAL;
 551                         goto out;
 552 #endif
 553                 case Opt_noacl:
 554                         info->sb->s_flags &= ~SB_POSIXACL;
 555                         break;
 556                 case Opt_notreelog:
 557                         btrfs_set_and_info(info, NOTREELOG,
 558                                            "disabling tree log");
 559                         break;
 560                 case Opt_treelog:
 561                         btrfs_clear_and_info(info, NOTREELOG,
 562                                              "enabling tree log");
 563                         break;
 564                 case Opt_norecovery:
 565                 case Opt_nologreplay:
 566                         btrfs_warn(info,
 567                 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
 568                         btrfs_set_and_info(info, NOLOGREPLAY,
 569                                            "disabling log replay at mount time");
 570                         break;
 571                 case Opt_flushoncommit:
 572                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 573                                            "turning on flush-on-commit");
 574                         break;
 575                 case Opt_noflushoncommit:
 576                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 577                                              "turning off flush-on-commit");
 578                         break;
 579                 case Opt_ratio:
 580                         ret = match_int(&args[0], &intarg);
 581                         if (ret) {
 582                                 btrfs_err(info, "unrecognized metadata_ratio value %s",
 583                                           args[0].from);
 584                                 goto out;
 585                         }
 586                         info->metadata_ratio = intarg;
 587                         btrfs_info(info, "metadata ratio %u",
 588                                    info->metadata_ratio);
 589                         break;
 590                 case Opt_discard:
 591                 case Opt_discard_mode:
 592                         if (token == Opt_discard ||
 593                             strcmp(args[0].from, "sync") == 0) {
 594                                 btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
 595                                 btrfs_set_and_info(info, DISCARD_SYNC,
 596                                                    "turning on sync discard");
 597                         } else if (strcmp(args[0].from, "async") == 0) {
 598                                 btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
 599                                 btrfs_set_and_info(info, DISCARD_ASYNC,
 600                                                    "turning on async discard");
 601                         } else {
 602                                 btrfs_err(info, "unrecognized discard mode value %s",
 603                                           args[0].from);
 604                                 ret = -EINVAL;
 605                                 goto out;
 606                         }
 607                         btrfs_clear_opt(info->mount_opt, NODISCARD);
 608                         break;
 609                 case Opt_nodiscard:
 610                         btrfs_clear_and_info(info, DISCARD_SYNC,
 611                                              "turning off discard");
 612                         btrfs_clear_and_info(info, DISCARD_ASYNC,
 613                                              "turning off async discard");
 614                         btrfs_set_opt(info->mount_opt, NODISCARD);
 615                         break;
 616                 case Opt_space_cache:
 617                 case Opt_space_cache_version:
 618                         /*
 619                          * We already set FREE_SPACE_TREE above because we have
 620                          * compat_ro(FREE_SPACE_TREE) set, and we aren't going
 621                          * to allow v1 to be set for extent tree v2, simply
 622                          * ignore this setting if we're extent tree v2.
 623                          */
 624                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 625                                 break;
 626                         if (token == Opt_space_cache ||
 627                             strcmp(args[0].from, "v1") == 0) {
 628                                 btrfs_clear_opt(info->mount_opt,
 629                                                 FREE_SPACE_TREE);
 630                                 btrfs_set_and_info(info, SPACE_CACHE,
 631                                            "enabling disk space caching");
 632                         } else if (strcmp(args[0].from, "v2") == 0) {
 633                                 btrfs_clear_opt(info->mount_opt,
 634                                                 SPACE_CACHE);
 635                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 636                                                    "enabling free space tree");
 637                         } else {
 638                                 btrfs_err(info, "unrecognized space_cache value %s",
 639                                           args[0].from);
 640                                 ret = -EINVAL;
 641                                 goto out;
 642                         }
 643                         break;
 644                 case Opt_rescan_uuid_tree:
 645                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 646                         break;
 647                 case Opt_no_space_cache:
 648                         /*
 649                          * We cannot operate without the free space tree with
 650                          * extent tree v2, ignore this option.
 651                          */
 652                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 653                                 break;
 654                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 655                                 btrfs_clear_and_info(info, SPACE_CACHE,
 656                                              "disabling disk space caching");
 657                         }
 658                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 659                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 660                                              "disabling free space tree");
 661                         }
 662                         break;
 663                 case Opt_inode_cache:
 664                 case Opt_noinode_cache:
 665                         btrfs_warn(info,
 666         "the 'inode_cache' option is deprecated and has no effect since 5.11");
 667                         break;
 668                 case Opt_clear_cache:
 669                         /*
 670                          * We cannot clear the free space tree with extent tree
 671                          * v2, ignore this option.
 672                          */
 673                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 674                                 break;
 675                         btrfs_set_and_info(info, CLEAR_CACHE,
 676                                            "force clearing of disk cache");
 677                         break;
 678                 case Opt_user_subvol_rm_allowed:
 679                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 680                         break;
 681                 case Opt_enospc_debug:
 682                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 683                         break;
 684                 case Opt_noenospc_debug:
 685                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 686                         break;
 687                 case Opt_defrag:
 688                         btrfs_set_and_info(info, AUTO_DEFRAG,
 689                                            "enabling auto defrag");
 690                         break;
 691                 case Opt_nodefrag:
 692                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 693                                              "disabling auto defrag");
 694                         break;
 695                 case Opt_recovery:
 696                 case Opt_usebackuproot:
 697                         btrfs_warn(info,
 698                         "'%s' is deprecated, use 'rescue=usebackuproot' instead",
 699                                    token == Opt_recovery ? "recovery" :
 700                                    "usebackuproot");
 701                         btrfs_info(info,
 702                                    "trying to use backup root at mount time");
 703                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 704                         break;
 705                 case Opt_skip_balance:
 706                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 707                         break;
 708                 case Opt_fatal_errors:
 709                         if (strcmp(args[0].from, "panic") == 0) {
 710                                 btrfs_set_opt(info->mount_opt,
 711                                               PANIC_ON_FATAL_ERROR);
 712                         } else if (strcmp(args[0].from, "bug") == 0) {
 713                                 btrfs_clear_opt(info->mount_opt,
 714                                               PANIC_ON_FATAL_ERROR);
 715                         } else {
 716                                 btrfs_err(info, "unrecognized fatal_errors value %s",
 717                                           args[0].from);
 718                                 ret = -EINVAL;
 719                                 goto out;
 720                         }
 721                         break;
 722                 case Opt_commit_interval:
 723                         intarg = 0;
 724                         ret = match_int(&args[0], &intarg);
 725                         if (ret) {
 726                                 btrfs_err(info, "unrecognized commit_interval value %s",
 727                                           args[0].from);
 728                                 ret = -EINVAL;
 729                                 goto out;
 730                         }
 731                         if (intarg == 0) {
 732                                 btrfs_info(info,
 733                                            "using default commit interval %us",
 734                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 735                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
 736                         } else if (intarg > 300) {
 737                                 btrfs_warn(info, "excessive commit interval %d",
 738                                            intarg);
 739                         }
 740                         info->commit_interval = intarg;
 741                         break;
 742                 case Opt_rescue:
 743                         ret = parse_rescue_options(info, args[0].from);
 744                         if (ret < 0) {
 745                                 btrfs_err(info, "unrecognized rescue value %s",
 746                                           args[0].from);
 747                                 goto out;
 748                         }
 749                         break;
 750 #ifdef CONFIG_BTRFS_DEBUG
 751                 case Opt_fragment_all:
 752                         btrfs_info(info, "fragmenting all space");
 753                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 754                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 755                         break;
 756                 case Opt_fragment_metadata:
 757                         btrfs_info(info, "fragmenting metadata");
 758                         btrfs_set_opt(info->mount_opt,
 759                                       FRAGMENT_METADATA);
 760                         break;
 761                 case Opt_fragment_data:
 762                         btrfs_info(info, "fragmenting data");
 763                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 764                         break;
 765 #endif
 766 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 767                 case Opt_ref_verify:
 768                         btrfs_info(info, "doing ref verification");
 769                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 770                         break;
 771 #endif
 772                 case Opt_err:
 773                         btrfs_err(info, "unrecognized mount option '%s'", p);
 774                         ret = -EINVAL;
 775                         goto out;
 776                 default:
 777                         break;
 778                 }
 779         }
 780 check:
 781         /* We're read-only, don't have to check. */
 782         if (new_flags & SB_RDONLY)
 783                 goto out;
 784
 785         if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
 786             check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
 787             check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))
 788                 ret = -EINVAL;
 789 out:
 790         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 791             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 792             !btrfs_test_opt(info, CLEAR_CACHE)) {
 793                 btrfs_err(info, "cannot disable free space tree");
 794                 ret = -EINVAL;
 795         }
 796         if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
 797              !btrfs_test_opt(info, FREE_SPACE_TREE)) {
 798                 btrfs_err(info, "cannot disable free space tree with block-group-tree feature");
 799                 ret = -EINVAL;
 800         }
 801         if (!ret)
 802                 ret = btrfs_check_mountopts_zoned(info);
 803         if (!ret && !remounting) {
 804                 if (btrfs_test_opt(info, SPACE_CACHE))
 805                         btrfs_info(info, "disk space caching is enabled");
 806                 if (btrfs_test_opt(info, FREE_SPACE_TREE))
 807                         btrfs_info(info, "using free space tree");
 808         }
 809         return ret;
 810 }
 811
 812 /*
 813  * Parse mount options that are required early in the mount process.
 814  *
 815  * All other options will be parsed on much later in the mount process and
 816  * only when we need to allocate a new super block.
 817  */
 818 static int btrfs_parse_device_options(const char *options, blk_mode_t flags)
 819 {
 820         substring_t args[MAX_OPT_ARGS];
 821         char *device_name, *opts, *orig, *p;
 822         struct btrfs_device *device = NULL;
 823         int error = 0;
 824
 825         lockdep_assert_held(&uuid_mutex);
 826
 827         if (!options)
 828                 return 0;
 829
 830         /*
 831          * strsep changes the string, duplicate it because btrfs_parse_options
 832          * gets called later
 833          */
 834         opts = kstrdup(options, GFP_KERNEL);
 835         if (!opts)
 836                 return -ENOMEM;
 837         orig = opts;
 838
 839         while ((p = strsep(&opts, ",")) != NULL) {
 840                 int token;
 841
 842                 if (!*p)
 843                         continue;
 844
 845                 token = match_token(p, tokens, args);
 846                 if (token == Opt_device) {
 847                         device_name = match_strdup(&args[0]);
 848                         if (!device_name) {
 849                                 error = -ENOMEM;
 850                                 goto out;
 851                         }
 852                         device = btrfs_scan_one_device(device_name, flags, false);
 853                         kfree(device_name);
 854                         if (IS_ERR(device)) {
 855                                 error = PTR_ERR(device);
 856                                 goto out;
 857                         }
 858                 }
 859         }
 860
 861 out:
 862         kfree(orig);
 863         return error;
 864 }
 865
 866 /*
 867  * Parse mount options that are related to subvolume id
 868  *
 869  * The value is later passed to mount_subvol()
 870  */
 871 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
 872                 u64 *subvol_objectid)
 873 {
 874         substring_t args[MAX_OPT_ARGS];
 875         char *opts, *orig, *p;
 876         int error = 0;
 877         u64 subvolid;
 878
 879         if (!options)
 880                 return 0;
 881
 882         /*
 883          * strsep changes the string, duplicate it because
 884          * btrfs_parse_device_options gets called later
 885          */
 886         opts = kstrdup(options, GFP_KERNEL);
 887         if (!opts)
 888                 return -ENOMEM;
 889         orig = opts;
 890
 891         while ((p = strsep(&opts, ",")) != NULL) {
 892                 int token;
 893                 if (!*p)
 894                         continue;
 895
 896                 token = match_token(p, tokens, args);
 897                 switch (token) {
 898                 case Opt_subvol:
 899                         kfree(*subvol_name);
 900                         *subvol_name = match_strdup(&args[0]);
 901                         if (!*subvol_name) {
 902                                 error = -ENOMEM;
 903                                 goto out;
 904                         }
 905                         break;
 906                 case Opt_subvolid:
 907                         error = match_u64(&args[0], &subvolid);
 908                         if (error)
 909                                 goto out;
 910
 911                         /* we want the original fs_tree */
 912                         if (subvolid == 0)
 913                                 subvolid = BTRFS_FS_TREE_OBJECTID;
 914
 915                         *subvol_objectid = subvolid;
 916                         break;
 917                 default:
 918                         break;
 919                 }
 920         }
 921
 922 out:
 923         kfree(orig);
 924         return error;
 925 }
 926
 927 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 928                                           u64 subvol_objectid)
 929 {
 930         struct btrfs_root *root = fs_info->tree_root;
 931         struct btrfs_root *fs_root = NULL;
 932         struct btrfs_root_ref *root_ref;
 933         struct btrfs_inode_ref *inode_ref;
 934         struct btrfs_key key;
 935         struct btrfs_path *path = NULL;
 936         char *name = NULL, *ptr;
 937         u64 dirid;
 938         int len;
 939         int ret;
 940
 941         path = btrfs_alloc_path();
 942         if (!path) {
 943                 ret = -ENOMEM;
 944                 goto err;
 945         }
 946
 947         name = kmalloc(PATH_MAX, GFP_KERNEL);
 948         if (!name) {
 949                 ret = -ENOMEM;
 950                 goto err;
 951         }
 952         ptr = name + PATH_MAX - 1;
 953         ptr[0] = '\0';
 954
 955         /*
 956          * Walk up the subvolume trees in the tree of tree roots by root
 957          * backrefs until we hit the top-level subvolume.
 958          */
 959         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 960                 key.objectid = subvol_objectid;
 961                 key.type = BTRFS_ROOT_BACKREF_KEY;
 962                 key.offset = (u64)-1;
 963
 964                 ret = btrfs_search_backwards(root, &key, path);
 965                 if (ret < 0) {
 966                         goto err;
 967                 } else if (ret > 0) {
 968                         ret = -ENOENT;
 969                         goto err;
 970                 }
 971
 972                 subvol_objectid = key.offset;
 973
 974                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 975                                           struct btrfs_root_ref);
 976                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
 977                 ptr -= len + 1;
 978                 if (ptr < name) {
 979                         ret = -ENAMETOOLONG;
 980                         goto err;
 981                 }
 982                 read_extent_buffer(path->nodes[0], ptr + 1,
 983                                    (unsigned long)(root_ref + 1), len);
 984                 ptr[0] = '/';
 985                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
 986                 btrfs_release_path(path);
 987
 988                 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
 989                 if (IS_ERR(fs_root)) {
 990                         ret = PTR_ERR(fs_root);
 991                         fs_root = NULL;
 992                         goto err;
 993                 }
 994
 995                 /*
 996                  * Walk up the filesystem tree by inode refs until we hit the
 997                  * root directory.
 998                  */
 999                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1000                         key.objectid = dirid;
1001                         key.type = BTRFS_INODE_REF_KEY;
1002                         key.offset = (u64)-1;
1003
1004                         ret = btrfs_search_backwards(fs_root, &key, path);
1005                         if (ret < 0) {
1006                                 goto err;
1007                         } else if (ret > 0) {
1008                                 ret = -ENOENT;
1009                                 goto err;
1010                         }
1011
1012                         dirid = key.offset;
1013
1014                         inode_ref = btrfs_item_ptr(path->nodes[0],
1015                                                    path->slots[0],
1016                                                    struct btrfs_inode_ref);
1017                         len = btrfs_inode_ref_name_len(path->nodes[0],
1018                                                        inode_ref);
1019                         ptr -= len + 1;
1020                         if (ptr < name) {
1021                                 ret = -ENAMETOOLONG;
1022                                 goto err;
1023                         }
1024                         read_extent_buffer(path->nodes[0], ptr + 1,
1025                                            (unsigned long)(inode_ref + 1), len);
1026                         ptr[0] = '/';
1027                         btrfs_release_path(path);
1028                 }
1029                 btrfs_put_root(fs_root);
1030                 fs_root = NULL;
1031         }
1032
1033         btrfs_free_path(path);
1034         if (ptr == name + PATH_MAX - 1) {
1035                 name[0] = '/';
1036                 name[1] = '\0';
1037         } else {
1038                 memmove(name, ptr, name + PATH_MAX - ptr);
1039         }
1040         return name;
1041
1042 err:
1043         btrfs_put_root(fs_root);
1044         btrfs_free_path(path);
1045         kfree(name);
1046         return ERR_PTR(ret);
1047 }
1048
1049 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1050 {
1051         struct btrfs_root *root = fs_info->tree_root;
1052         struct btrfs_dir_item *di;
1053         struct btrfs_path *path;
1054         struct btrfs_key location;
1055         struct fscrypt_str name = FSTR_INIT("default", 7);
1056         u64 dir_id;
1057
1058         path = btrfs_alloc_path();
1059         if (!path)
1060                 return -ENOMEM;
1061
1062         /*
1063          * Find the "default" dir item which points to the root item that we
1064          * will mount by default if we haven't been given a specific subvolume
1065          * to mount.
1066          */
1067         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1068         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
1069         if (IS_ERR(di)) {
1070                 btrfs_free_path(path);
1071                 return PTR_ERR(di);
1072         }
1073         if (!di) {
1074                 /*
1075                  * Ok the default dir item isn't there.  This is weird since
1076                  * it's always been there, but don't freak out, just try and
1077                  * mount the top-level subvolume.
1078                  */
1079                 btrfs_free_path(path);
1080                 *objectid = BTRFS_FS_TREE_OBJECTID;
1081                 return 0;
1082         }
1083
1084         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1085         btrfs_free_path(path);
1086         *objectid = location.objectid;
1087         return 0;
1088 }
1089
1090 static int btrfs_fill_super(struct super_block *sb,
1091                             struct btrfs_fs_devices *fs_devices,
1092                             void *data)
1093 {
1094         struct inode *inode;
1095         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1096         int err;
1097
1098         sb->s_maxbytes = MAX_LFS_FILESIZE;
1099         sb->s_magic = BTRFS_SUPER_MAGIC;
1100         sb->s_op = &btrfs_super_ops;
1101         sb->s_d_op = &btrfs_dentry_operations;
1102         sb->s_export_op = &btrfs_export_ops;
1103 #ifdef CONFIG_FS_VERITY
1104         sb->s_vop = &btrfs_verityops;
1105 #endif
1106         sb->s_xattr = btrfs_xattr_handlers;
1107         sb->s_time_gran = 1;
1108 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1109         sb->s_flags |= SB_POSIXACL;
1110 #endif
1111         sb->s_flags |= SB_I_VERSION;
1112         sb->s_iflags |= SB_I_CGROUPWB;
1113
1114         err = super_setup_bdi(sb);
1115         if (err) {
1116                 btrfs_err(fs_info, "super_setup_bdi failed");
1117                 return err;
1118         }
1119
1120         err = open_ctree(sb, fs_devices, (char *)data);
1121         if (err) {
1122                 btrfs_err(fs_info, "open_ctree failed");
1123                 return err;
1124         }
1125
1126         inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1127         if (IS_ERR(inode)) {
1128                 err = PTR_ERR(inode);
1129                 btrfs_handle_fs_error(fs_info, err, NULL);
1130                 goto fail_close;
1131         }
1132
1133         sb->s_root = d_make_root(inode);
1134         if (!sb->s_root) {
1135                 err = -ENOMEM;
1136                 goto fail_close;
1137         }
1138
1139         sb->s_flags |= SB_ACTIVE;
1140         return 0;
1141
1142 fail_close:
1143         close_ctree(fs_info);
1144         return err;
1145 }
1146
1147 int btrfs_sync_fs(struct super_block *sb, int wait)
1148 {
1149         struct btrfs_trans_handle *trans;
1150         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1151         struct btrfs_root *root = fs_info->tree_root;
1152
1153         trace_btrfs_sync_fs(fs_info, wait);
1154
1155         if (!wait) {
1156                 filemap_flush(fs_info->btree_inode->i_mapping);
1157                 return 0;
1158         }
1159
1160         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1161
1162         trans = btrfs_attach_transaction_barrier(root);
1163         if (IS_ERR(trans)) {
1164                 /* no transaction, don't bother */
1165                 if (PTR_ERR(trans) == -ENOENT) {
1166                         /*
1167                          * Exit unless we have some pending changes
1168                          * that need to go through commit
1169                          */
1170                         if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
1171                                       &fs_info->flags))
1172                                 return 0;
1173                         /*
1174                          * A non-blocking test if the fs is frozen. We must not
1175                          * start a new transaction here otherwise a deadlock
1176                          * happens. The pending operations are delayed to the
1177                          * next commit after thawing.
1178                          */
1179                         if (sb_start_write_trylock(sb))
1180                                 sb_end_write(sb);
1181                         else
1182                                 return 0;
1183                         trans = btrfs_start_transaction(root, 0);
1184                 }
1185                 if (IS_ERR(trans))
1186                         return PTR_ERR(trans);
1187         }
1188         return btrfs_commit_transaction(trans);
1189 }
1190
1191 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1192 {
1193         seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1194         *printed = true;
1195 }
1196
1197 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1198 {
1199         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1200         const char *compress_type;
1201         const char *subvol_name;
1202         bool printed = false;
1203
1204         if (btrfs_test_opt(info, DEGRADED))
1205                 seq_puts(seq, ",degraded");
1206         if (btrfs_test_opt(info, NODATASUM))
1207                 seq_puts(seq, ",nodatasum");
1208         if (btrfs_test_opt(info, NODATACOW))
1209                 seq_puts(seq, ",nodatacow");
1210         if (btrfs_test_opt(info, NOBARRIER))
1211                 seq_puts(seq, ",nobarrier");
1212         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1213                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1214         if (info->thread_pool_size !=  min_t(unsigned long,
1215                                              num_online_cpus() + 2, 8))
1216                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1217         if (btrfs_test_opt(info, COMPRESS)) {
1218                 compress_type = btrfs_compress_type2str(info->compress_type);
1219                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1220                         seq_printf(seq, ",compress-force=%s", compress_type);
1221                 else
1222                         seq_printf(seq, ",compress=%s", compress_type);
1223                 if (info->compress_level)
1224                         seq_printf(seq, ":%d", info->compress_level);
1225         }
1226         if (btrfs_test_opt(info, NOSSD))
1227                 seq_puts(seq, ",nossd");
1228         if (btrfs_test_opt(info, SSD_SPREAD))
1229                 seq_puts(seq, ",ssd_spread");
1230         else if (btrfs_test_opt(info, SSD))
1231                 seq_puts(seq, ",ssd");
1232         if (btrfs_test_opt(info, NOTREELOG))
1233                 seq_puts(seq, ",notreelog");
1234         if (btrfs_test_opt(info, NOLOGREPLAY))
1235                 print_rescue_option(seq, "nologreplay", &printed);
1236         if (btrfs_test_opt(info, USEBACKUPROOT))
1237                 print_rescue_option(seq, "usebackuproot", &printed);
1238         if (btrfs_test_opt(info, IGNOREBADROOTS))
1239                 print_rescue_option(seq, "ignorebadroots", &printed);
1240         if (btrfs_test_opt(info, IGNOREDATACSUMS))
1241                 print_rescue_option(seq, "ignoredatacsums", &printed);
1242         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1243                 seq_puts(seq, ",flushoncommit");
1244         if (btrfs_test_opt(info, DISCARD_SYNC))
1245                 seq_puts(seq, ",discard");
1246         if (btrfs_test_opt(info, DISCARD_ASYNC))
1247                 seq_puts(seq, ",discard=async");
1248         if (!(info->sb->s_flags & SB_POSIXACL))
1249                 seq_puts(seq, ",noacl");
1250         if (btrfs_free_space_cache_v1_active(info))
1251                 seq_puts(seq, ",space_cache");
1252         else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1253                 seq_puts(seq, ",space_cache=v2");
1254         else
1255                 seq_puts(seq, ",nospace_cache");
1256         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1257                 seq_puts(seq, ",rescan_uuid_tree");
1258         if (btrfs_test_opt(info, CLEAR_CACHE))
1259                 seq_puts(seq, ",clear_cache");
1260         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1261                 seq_puts(seq, ",user_subvol_rm_allowed");
1262         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1263                 seq_puts(seq, ",enospc_debug");
1264         if (btrfs_test_opt(info, AUTO_DEFRAG))
1265                 seq_puts(seq, ",autodefrag");
1266         if (btrfs_test_opt(info, SKIP_BALANCE))
1267                 seq_puts(seq, ",skip_balance");
1268         if (info->metadata_ratio)
1269                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1270         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1271                 seq_puts(seq, ",fatal_errors=panic");
1272         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1273                 seq_printf(seq, ",commit=%u", info->commit_interval);
1274 #ifdef CONFIG_BTRFS_DEBUG
1275         if (btrfs_test_opt(info, FRAGMENT_DATA))
1276                 seq_puts(seq, ",fragment=data");
1277         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1278                 seq_puts(seq, ",fragment=metadata");
1279 #endif
1280         if (btrfs_test_opt(info, REF_VERIFY))
1281                 seq_puts(seq, ",ref_verify");
1282         seq_printf(seq, ",subvolid=%llu",
1283                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1284         subvol_name = btrfs_get_subvol_name_from_objectid(info,
1285                         BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1286         if (!IS_ERR(subvol_name)) {
1287                 seq_puts(seq, ",subvol=");
1288                 seq_escape(seq, subvol_name, " \t\n\\");
1289                 kfree(subvol_name);
1290         }
1291         return 0;
1292 }
1293
1294 static int btrfs_test_super(struct super_block *s, void *data)
1295 {
1296         struct btrfs_fs_info *p = data;
1297         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1298
1299         return fs_info->fs_devices == p->fs_devices;
1300 }
1301
1302 static int btrfs_set_super(struct super_block *s, void *data)
1303 {
1304         int err = set_anon_super(s, data);
1305         if (!err)
1306                 s->s_fs_info = data;
1307         return err;
1308 }
1309
1310 /*
1311  * subvolumes are identified by ino 256
1312  */
1313 static inline int is_subvolume_inode(struct inode *inode)
1314 {
1315         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1316                 return 1;
1317         return 0;
1318 }
1319
1320 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1321                                    struct vfsmount *mnt)
1322 {
1323         struct dentry *root;
1324         int ret;
1325
1326         if (!subvol_name) {
1327                 if (!subvol_objectid) {
1328                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1329                                                           &subvol_objectid);
1330                         if (ret) {
1331                                 root = ERR_PTR(ret);
1332                                 goto out;
1333                         }
1334                 }
1335                 subvol_name = btrfs_get_subvol_name_from_objectid(
1336                                         btrfs_sb(mnt->mnt_sb), subvol_objectid);
1337                 if (IS_ERR(subvol_name)) {
1338                         root = ERR_CAST(subvol_name);
1339                         subvol_name = NULL;
1340                         goto out;
1341                 }
1342
1343         }
1344
1345         root = mount_subtree(mnt, subvol_name);
1346         /* mount_subtree() drops our reference on the vfsmount. */
1347         mnt = NULL;
1348
1349         if (!IS_ERR(root)) {
1350                 struct super_block *s = root->d_sb;
1351                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1352                 struct inode *root_inode = d_inode(root);
1353                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1354
1355                 ret = 0;
1356                 if (!is_subvolume_inode(root_inode)) {
1357                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1358                                subvol_name);
1359                         ret = -EINVAL;
1360                 }
1361                 if (subvol_objectid && root_objectid != subvol_objectid) {
1362                         /*
1363                          * This will also catch a race condition where a
1364                          * subvolume which was passed by ID is renamed and
1365                          * another subvolume is renamed over the old location.
1366                          */
1367                         btrfs_err(fs_info,
1368                                   "subvol '%s' does not match subvolid %llu",
1369                                   subvol_name, subvol_objectid);
1370                         ret = -EINVAL;
1371                 }
1372                 if (ret) {
1373                         dput(root);
1374                         root = ERR_PTR(ret);
1375                         deactivate_locked_super(s);
1376                 }
1377         }
1378
1379 out:
1380         mntput(mnt);
1381         kfree(subvol_name);
1382         return root;
1383 }
1384
1385 /*
1386  * Find a superblock for the given device / mount point.
1387  *
1388  * Note: This is based on mount_bdev from fs/super.c with a few additions
1389  *       for multiple device setup.  Make sure to keep it in sync.
1390  */
1391 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1392                 int flags, const char *device_name, void *data)
1393 {
1394         struct block_device *bdev = NULL;
1395         struct super_block *s;
1396         struct btrfs_device *device = NULL;
1397         struct btrfs_fs_devices *fs_devices = NULL;
1398         struct btrfs_fs_info *fs_info = NULL;
1399         void *new_sec_opts = NULL;
1400         blk_mode_t mode = sb_open_mode(flags);
1401         int error = 0;
1402
1403         if (data) {
1404                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1405                 if (error)
1406                         return ERR_PTR(error);
1407         }
1408
1409         /* No support for restricting writes to btrfs devices yet... */
1410         mode &= ~BLK_OPEN_RESTRICT_WRITES;
1411         /*
1412          * Setup a dummy root and fs_info for test/set super.  This is because
1413          * we don't actually fill this stuff out until open_ctree, but we need
1414          * then open_ctree will properly initialize the file system specific
1415          * settings later.  btrfs_init_fs_info initializes the static elements
1416          * of the fs_info (locks and such) to make cleanup easier if we find a
1417          * superblock with our given fs_devices later on at sget() time.
1418          */
1419         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1420         if (!fs_info) {
1421                 error = -ENOMEM;
1422                 goto error_sec_opts;
1423         }
1424         btrfs_init_fs_info(fs_info);
1425
1426         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1427         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1428         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1429                 error = -ENOMEM;
1430                 goto error_fs_info;
1431         }
1432
1433         mutex_lock(&uuid_mutex);
1434         error = btrfs_parse_device_options(data, mode);
1435         if (error) {
1436                 mutex_unlock(&uuid_mutex);
1437                 goto error_fs_info;
1438         }
1439
1440         /*
1441          * With 'true' passed to btrfs_scan_one_device() (mount time) we expect
1442          * either a valid device or an error.
1443          */
1444         device = btrfs_scan_one_device(device_name, mode, true);
1445         ASSERT(device != NULL);
1446         if (IS_ERR(device)) {
1447                 mutex_unlock(&uuid_mutex);
1448                 error = PTR_ERR(device);
1449                 goto error_fs_info;
1450         }
1451
1452         fs_devices = device->fs_devices;
1453         fs_info->fs_devices = fs_devices;
1454
1455         error = btrfs_open_devices(fs_devices, mode, fs_type);
1456         mutex_unlock(&uuid_mutex);
1457         if (error)
1458                 goto error_fs_info;
1459
1460         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1461                 error = -EACCES;
1462                 goto error_close_devices;
1463         }
1464
1465         bdev = fs_devices->latest_dev->bdev;
1466         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1467                  fs_info);
1468         if (IS_ERR(s)) {
1469                 error = PTR_ERR(s);
1470                 goto error_close_devices;
1471         }
1472
1473         if (s->s_root) {
1474                 btrfs_close_devices(fs_devices);
1475                 btrfs_free_fs_info(fs_info);
1476                 if ((flags ^ s->s_flags) & SB_RDONLY)
1477                         error = -EBUSY;
1478         } else {
1479                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1480                 shrinker_debugfs_rename(s->s_shrink, "sb-%s:%s", fs_type->name,
1481                                         s->s_id);
1482                 btrfs_sb(s)->bdev_holder = fs_type;
1483                 error = btrfs_fill_super(s, fs_devices, data);
1484         }
1485         if (!error)
1486                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1487         security_free_mnt_opts(&new_sec_opts);
1488         if (error) {
1489                 deactivate_locked_super(s);
1490                 return ERR_PTR(error);
1491         }
1492
1493         return dget(s->s_root);
1494
1495 error_close_devices:
1496         btrfs_close_devices(fs_devices);
1497 error_fs_info:
1498         btrfs_free_fs_info(fs_info);
1499 error_sec_opts:
1500         security_free_mnt_opts(&new_sec_opts);
1501         return ERR_PTR(error);
1502 }
1503
1504 /*
1505  * Mount function which is called by VFS layer.
1506  *
1507  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1508  * which needs vfsmount* of device's root (/).  This means device's root has to
1509  * be mounted internally in any case.
1510  *
1511  * Operation flow:
1512  *   1. Parse subvol id related options for later use in mount_subvol().
1513  *
1514  *   2. Mount device's root (/) by calling vfs_kern_mount().
1515  *
1516  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1517  *      first place. In order to avoid calling btrfs_mount() again, we use
1518  *      different file_system_type which is not registered to VFS by
1519  *      register_filesystem() (btrfs_root_fs_type). As a result,
1520  *      btrfs_mount_root() is called. The return value will be used by
1521  *      mount_subtree() in mount_subvol().
1522  *
1523  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1524  *      "btrfs subvolume set-default", mount_subvol() is called always.
1525  */
1526 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1527                 const char *device_name, void *data)
1528 {
1529         struct vfsmount *mnt_root;
1530         struct dentry *root;
1531         char *subvol_name = NULL;
1532         u64 subvol_objectid = 0;
1533         int error = 0;
1534
1535         error = btrfs_parse_subvol_options(data, &subvol_name,
1536                                         &subvol_objectid);
1537         if (error) {
1538                 kfree(subvol_name);
1539                 return ERR_PTR(error);
1540         }
1541
1542         /* mount device's root (/) */
1543         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1544         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1545                 if (flags & SB_RDONLY) {
1546                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1547                                 flags & ~SB_RDONLY, device_name, data);
1548                 } else {
1549                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1550                                 flags | SB_RDONLY, device_name, data);
1551                         if (IS_ERR(mnt_root)) {
1552                                 root = ERR_CAST(mnt_root);
1553                                 kfree(subvol_name);
1554                                 goto out;
1555                         }
1556
1557                         down_write(&mnt_root->mnt_sb->s_umount);
1558                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1559                         up_write(&mnt_root->mnt_sb->s_umount);
1560                         if (error < 0) {
1561                                 root = ERR_PTR(error);
1562                                 mntput(mnt_root);
1563                                 kfree(subvol_name);
1564                                 goto out;
1565                         }
1566                 }
1567         }
1568         if (IS_ERR(mnt_root)) {
1569                 root = ERR_CAST(mnt_root);
1570                 kfree(subvol_name);
1571                 goto out;
1572         }
1573
1574         /* mount_subvol() will free subvol_name and mnt_root */
1575         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1576
1577 out:
1578         return root;
1579 }
1580
1581 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1582                                      u32 new_pool_size, u32 old_pool_size)
1583 {
1584         if (new_pool_size == old_pool_size)
1585                 return;
1586
1587         fs_info->thread_pool_size = new_pool_size;
1588
1589         btrfs_info(fs_info, "resize thread pool %d -> %d",
1590                old_pool_size, new_pool_size);
1591
1592         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1593         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1594         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1595         workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1596         workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1597         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1598         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1599         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1600 }
1601
1602 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1603                                        unsigned long old_opts, int flags)
1604 {
1605         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1606             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1607              (flags & SB_RDONLY))) {
1608                 /* wait for any defraggers to finish */
1609                 wait_event(fs_info->transaction_wait,
1610                            (atomic_read(&fs_info->defrag_running) == 0));
1611                 if (flags & SB_RDONLY)
1612                         sync_filesystem(fs_info->sb);
1613         }
1614 }
1615
1616 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1617                                          unsigned long old_opts)
1618 {
1619         const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1620
1621         /*
1622          * We need to cleanup all defragable inodes if the autodefragment is
1623          * close or the filesystem is read only.
1624          */
1625         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1626             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1627                 btrfs_cleanup_defrag_inodes(fs_info);
1628         }
1629
1630         /* If we toggled discard async */
1631         if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1632             btrfs_test_opt(fs_info, DISCARD_ASYNC))
1633                 btrfs_discard_resume(fs_info);
1634         else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1635                  !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1636                 btrfs_discard_cleanup(fs_info);
1637
1638         /* If we toggled space cache */
1639         if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1640                 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1641 }
1642
1643 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1644 {
1645         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1646         unsigned old_flags = sb->s_flags;
1647         unsigned long old_opts = fs_info->mount_opt;
1648         unsigned long old_compress_type = fs_info->compress_type;
1649         u64 old_max_inline = fs_info->max_inline;
1650         u32 old_thread_pool_size = fs_info->thread_pool_size;
1651         u32 old_metadata_ratio = fs_info->metadata_ratio;
1652         int ret;
1653
1654         sync_filesystem(sb);
1655         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1656
1657         if (data) {
1658                 void *new_sec_opts = NULL;
1659
1660                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1661                 if (!ret)
1662                         ret = security_sb_remount(sb, new_sec_opts);
1663                 security_free_mnt_opts(&new_sec_opts);
1664                 if (ret)
1665                         goto restore;
1666         }
1667
1668         ret = btrfs_parse_options(fs_info, data, *flags);
1669         if (ret)
1670                 goto restore;
1671
1672         ret = btrfs_check_features(fs_info, !(*flags & SB_RDONLY));
1673         if (ret < 0)
1674                 goto restore;
1675
1676         btrfs_remount_begin(fs_info, old_opts, *flags);
1677         btrfs_resize_thread_pool(fs_info,
1678                 fs_info->thread_pool_size, old_thread_pool_size);
1679
1680         if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1681             (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1682             (!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
1683                 btrfs_warn(fs_info,
1684                 "remount supports changing free space tree only from ro to rw");
1685                 /* Make sure free space cache options match the state on disk */
1686                 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1687                         btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1688                         btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1689                 }
1690                 if (btrfs_free_space_cache_v1_active(fs_info)) {
1691                         btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1692                         btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1693                 }
1694         }
1695
1696         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1697                 goto out;
1698
1699         if (*flags & SB_RDONLY) {
1700                 /*
1701                  * this also happens on 'umount -rf' or on shutdown, when
1702                  * the filesystem is busy.
1703                  */
1704                 cancel_work_sync(&fs_info->async_reclaim_work);
1705                 cancel_work_sync(&fs_info->async_data_reclaim_work);
1706
1707                 btrfs_discard_cleanup(fs_info);
1708
1709                 /* wait for the uuid_scan task to finish */
1710                 down(&fs_info->uuid_tree_rescan_sem);
1711                 /* avoid complains from lockdep et al. */
1712                 up(&fs_info->uuid_tree_rescan_sem);
1713
1714                 btrfs_set_sb_rdonly(sb);
1715
1716                 /*
1717                  * Setting SB_RDONLY will put the cleaner thread to
1718                  * sleep at the next loop if it's already active.
1719                  * If it's already asleep, we'll leave unused block
1720                  * groups on disk until we're mounted read-write again
1721                  * unless we clean them up here.
1722                  */
1723                 btrfs_delete_unused_bgs(fs_info);
1724
1725                 /*
1726                  * The cleaner task could be already running before we set the
1727                  * flag BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock).
1728                  * We must make sure that after we finish the remount, i.e. after
1729                  * we call btrfs_commit_super(), the cleaner can no longer start
1730                  * a transaction - either because it was dropping a dead root,
1731                  * running delayed iputs or deleting an unused block group (the
1732                  * cleaner picked a block group from the list of unused block
1733                  * groups before we were able to in the previous call to
1734                  * btrfs_delete_unused_bgs()).
1735                  */
1736                 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING,
1737                             TASK_UNINTERRUPTIBLE);
1738
1739                 /*
1740                  * We've set the superblock to RO mode, so we might have made
1741                  * the cleaner task sleep without running all pending delayed
1742                  * iputs. Go through all the delayed iputs here, so that if an
1743                  * unmount happens without remounting RW we don't end up at
1744                  * finishing close_ctree() with a non-empty list of delayed
1745                  * iputs.
1746                  */
1747                 btrfs_run_delayed_iputs(fs_info);
1748
1749                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1750                 btrfs_scrub_cancel(fs_info);
1751                 btrfs_pause_balance(fs_info);
1752
1753                 /*
1754                  * Pause the qgroup rescan worker if it is running. We don't want
1755                  * it to be still running after we are in RO mode, as after that,
1756                  * by the time we unmount, it might have left a transaction open,
1757                  * so we would leak the transaction and/or crash.
1758                  */
1759                 btrfs_qgroup_wait_for_completion(fs_info, false);
1760
1761                 ret = btrfs_commit_super(fs_info);
1762                 if (ret)
1763                         goto restore;
1764         } else {
1765                 if (BTRFS_FS_ERROR(fs_info)) {
1766                         btrfs_err(fs_info,
1767                                 "Remounting read-write after error is not allowed");
1768                         ret = -EINVAL;
1769                         goto restore;
1770                 }
1771                 if (fs_info->fs_devices->rw_devices == 0) {
1772                         ret = -EACCES;
1773                         goto restore;
1774                 }
1775
1776                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1777                         btrfs_warn(fs_info,
1778                 "too many missing devices, writable remount is not allowed");
1779                         ret = -EACCES;
1780                         goto restore;
1781                 }
1782
1783                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1784                         btrfs_warn(fs_info,
1785                 "mount required to replay tree-log, cannot remount read-write");
1786                         ret = -EINVAL;
1787                         goto restore;
1788                 }
1789
1790                 /*
1791                  * NOTE: when remounting with a change that does writes, don't
1792                  * put it anywhere above this point, as we are not sure to be
1793                  * safe to write until we pass the above checks.
1794                  */
1795                 ret = btrfs_start_pre_rw_mount(fs_info);
1796                 if (ret)
1797                         goto restore;
1798
1799                 btrfs_clear_sb_rdonly(sb);
1800
1801                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1802
1803                 /*
1804                  * If we've gone from readonly -> read/write, we need to get
1805                  * our sync/async discard lists in the right state.
1806                  */
1807                 btrfs_discard_resume(fs_info);
1808         }
1809 out:
1810         /*
1811          * We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
1812          * since the absence of the flag means it can be toggled off by remount.
1813          */
1814         *flags |= SB_I_VERSION;
1815
1816         wake_up_process(fs_info->transaction_kthread);
1817         btrfs_remount_cleanup(fs_info, old_opts);
1818         btrfs_clear_oneshot_options(fs_info);
1819         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1820
1821         return 0;
1822
1823 restore:
1824         /* We've hit an error - don't reset SB_RDONLY */
1825         if (sb_rdonly(sb))
1826                 old_flags |= SB_RDONLY;
1827         if (!(old_flags & SB_RDONLY))
1828                 clear_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
1829         sb->s_flags = old_flags;
1830         fs_info->mount_opt = old_opts;
1831         fs_info->compress_type = old_compress_type;
1832         fs_info->max_inline = old_max_inline;
1833         btrfs_resize_thread_pool(fs_info,
1834                 old_thread_pool_size, fs_info->thread_pool_size);
1835         fs_info->metadata_ratio = old_metadata_ratio;
1836         btrfs_remount_cleanup(fs_info, old_opts);
1837         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1838
1839         return ret;
1840 }
1841
1842 /* Used to sort the devices by max_avail(descending sort) */
1843 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1844 {
1845         const struct btrfs_device_info *dev_info1 = a;
1846         const struct btrfs_device_info *dev_info2 = b;
1847
1848         if (dev_info1->max_avail > dev_info2->max_avail)
1849                 return -1;
1850         else if (dev_info1->max_avail < dev_info2->max_avail)
1851                 return 1;
1852         return 0;
1853 }
1854
1855 /*
1856  * sort the devices by max_avail, in which max free extent size of each device
1857  * is stored.(Descending Sort)
1858  */
1859 static inline void btrfs_descending_sort_devices(
1860                                         struct btrfs_device_info *devices,
1861                                         size_t nr_devices)
1862 {
1863         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1864              btrfs_cmp_device_free_bytes, NULL);
1865 }
1866
1867 /*
1868  * The helper to calc the free space on the devices that can be used to store
1869  * file data.
1870  */
1871 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1872                                               u64 *free_bytes)
1873 {
1874         struct btrfs_device_info *devices_info;
1875         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1876         struct btrfs_device *device;
1877         u64 type;
1878         u64 avail_space;
1879         u64 min_stripe_size;
1880         int num_stripes = 1;
1881         int i = 0, nr_devices;
1882         const struct btrfs_raid_attr *rattr;
1883
1884         /*
1885          * We aren't under the device list lock, so this is racy-ish, but good
1886          * enough for our purposes.
1887          */
1888         nr_devices = fs_info->fs_devices->open_devices;
1889         if (!nr_devices) {
1890                 smp_mb();
1891                 nr_devices = fs_info->fs_devices->open_devices;
1892                 ASSERT(nr_devices);
1893                 if (!nr_devices) {
1894                         *free_bytes = 0;
1895                         return 0;
1896                 }
1897         }
1898
1899         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1900                                GFP_KERNEL);
1901         if (!devices_info)
1902                 return -ENOMEM;
1903
1904         /* calc min stripe number for data space allocation */
1905         type = btrfs_data_alloc_profile(fs_info);
1906         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1907
1908         if (type & BTRFS_BLOCK_GROUP_RAID0)
1909                 num_stripes = nr_devices;
1910         else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1911                 num_stripes = rattr->ncopies;
1912         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1913                 num_stripes = 4;
1914
1915         /* Adjust for more than 1 stripe per device */
1916         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1917
1918         rcu_read_lock();
1919         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1920                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1921                                                 &device->dev_state) ||
1922                     !device->bdev ||
1923                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1924                         continue;
1925
1926                 if (i >= nr_devices)
1927                         break;
1928
1929                 avail_space = device->total_bytes - device->bytes_used;
1930
1931                 /* align with stripe_len */
1932                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1933
1934                 /*
1935                  * Ensure we have at least min_stripe_size on top of the
1936                  * reserved space on the device.
1937                  */
1938                 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1939                         continue;
1940
1941                 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1942
1943                 devices_info[i].dev = device;
1944                 devices_info[i].max_avail = avail_space;
1945
1946                 i++;
1947         }
1948         rcu_read_unlock();
1949
1950         nr_devices = i;
1951
1952         btrfs_descending_sort_devices(devices_info, nr_devices);
1953
1954         i = nr_devices - 1;
1955         avail_space = 0;
1956         while (nr_devices >= rattr->devs_min) {
1957                 num_stripes = min(num_stripes, nr_devices);
1958
1959                 if (devices_info[i].max_avail >= min_stripe_size) {
1960                         int j;
1961                         u64 alloc_size;
1962
1963                         avail_space += devices_info[i].max_avail * num_stripes;
1964                         alloc_size = devices_info[i].max_avail;
1965                         for (j = i + 1 - num_stripes; j <= i; j++)
1966                                 devices_info[j].max_avail -= alloc_size;
1967                 }
1968                 i--;
1969                 nr_devices--;
1970         }
1971
1972         kfree(devices_info);
1973         *free_bytes = avail_space;
1974         return 0;
1975 }
1976
1977 /*
1978  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1979  *
1980  * If there's a redundant raid level at DATA block groups, use the respective
1981  * multiplier to scale the sizes.
1982  *
1983  * Unused device space usage is based on simulating the chunk allocator
1984  * algorithm that respects the device sizes and order of allocations.  This is
1985  * a close approximation of the actual use but there are other factors that may
1986  * change the result (like a new metadata chunk).
1987  *
1988  * If metadata is exhausted, f_bavail will be 0.
1989  */
1990 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1991 {
1992         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1993         struct btrfs_super_block *disk_super = fs_info->super_copy;
1994         struct btrfs_space_info *found;
1995         u64 total_used = 0;
1996         u64 total_free_data = 0;
1997         u64 total_free_meta = 0;
1998         u32 bits = fs_info->sectorsize_bits;
1999         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2000         unsigned factor = 1;
2001         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2002         int ret;
2003         u64 thresh = 0;
2004         int mixed = 0;
2005
2006         list_for_each_entry(found, &fs_info->space_info, list) {
2007                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2008                         int i;
2009
2010                         total_free_data += found->disk_total - found->disk_used;
2011                         total_free_data -=
2012                                 btrfs_account_ro_block_groups_free_space(found);
2013
2014                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2015                                 if (!list_empty(&found->block_groups[i]))
2016                                         factor = btrfs_bg_type_to_factor(
2017                                                 btrfs_raid_array[i].bg_flag);
2018                         }
2019                 }
2020
2021                 /*
2022                  * Metadata in mixed block group profiles are accounted in data
2023                  */
2024                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2025                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2026                                 mixed = 1;
2027                         else
2028                                 total_free_meta += found->disk_total -
2029                                         found->disk_used;
2030                 }
2031
2032                 total_used += found->disk_used;
2033         }
2034
2035         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2036         buf->f_blocks >>= bits;
2037         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2038
2039         /* Account global block reserve as used, it's in logical size already */
2040         spin_lock(&block_rsv->lock);
2041         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2042         if (buf->f_bfree >= block_rsv->size >> bits)
2043                 buf->f_bfree -= block_rsv->size >> bits;
2044         else
2045                 buf->f_bfree = 0;
2046         spin_unlock(&block_rsv->lock);
2047
2048         buf->f_bavail = div_u64(total_free_data, factor);
2049         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2050         if (ret)
2051                 return ret;
2052         buf->f_bavail += div_u64(total_free_data, factor);
2053         buf->f_bavail = buf->f_bavail >> bits;
2054
2055         /*
2056          * We calculate the remaining metadata space minus global reserve. If
2057          * this is (supposedly) smaller than zero, there's no space. But this
2058          * does not hold in practice, the exhausted state happens where's still
2059          * some positive delta. So we apply some guesswork and compare the
2060          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2061          *
2062          * We probably cannot calculate the exact threshold value because this
2063          * depends on the internal reservations requested by various
2064          * operations, so some operations that consume a few metadata will
2065          * succeed even if the Avail is zero. But this is better than the other
2066          * way around.
2067          */
2068         thresh = SZ_4M;
2069
2070         /*
2071          * We only want to claim there's no available space if we can no longer
2072          * allocate chunks for our metadata profile and our global reserve will
2073          * not fit in the free metadata space.  If we aren't ->full then we
2074          * still can allocate chunks and thus are fine using the currently
2075          * calculated f_bavail.
2076          */
2077         if (!mixed && block_rsv->space_info->full &&
2078             (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size))
2079                 buf->f_bavail = 0;
2080
2081         buf->f_type = BTRFS_SUPER_MAGIC;
2082         buf->f_bsize = dentry->d_sb->s_blocksize;
2083         buf->f_namelen = BTRFS_NAME_LEN;
2084
2085         /* We treat it as constant endianness (it doesn't matter _which_)
2086            because we want the fsid to come out the same whether mounted
2087            on a big-endian or little-endian host */
2088         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2089         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2090         /* Mask in the root object ID too, to disambiguate subvols */
2091         buf->f_fsid.val[0] ^=
2092                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2093         buf->f_fsid.val[1] ^=
2094                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2095
2096         return 0;
2097 }
2098
2099 static void btrfs_kill_super(struct super_block *sb)
2100 {
2101         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2102         kill_anon_super(sb);
2103         btrfs_free_fs_info(fs_info);
2104 }
2105
2106 static struct file_system_type btrfs_fs_type = {
2107         .owner          = THIS_MODULE,
2108         .name           = "btrfs",
2109         .mount          = btrfs_mount,
2110         .kill_sb        = btrfs_kill_super,
2111         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2112 };
2113
2114 static struct file_system_type btrfs_root_fs_type = {
2115         .owner          = THIS_MODULE,
2116         .name           = "btrfs",
2117         .mount          = btrfs_mount_root,
2118         .kill_sb        = btrfs_kill_super,
2119         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2120 };
2121
2122 MODULE_ALIAS_FS("btrfs");
2123
2124 static int btrfs_control_open(struct inode *inode, struct file *file)
2125 {
2126         /*
2127          * The control file's private_data is used to hold the
2128          * transaction when it is started and is used to keep
2129          * track of whether a transaction is already in progress.
2130          */
2131         file->private_data = NULL;
2132         return 0;
2133 }
2134
2135 /*
2136  * Used by /dev/btrfs-control for devices ioctls.
2137  */
2138 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2139                                 unsigned long arg)
2140 {
2141         struct btrfs_ioctl_vol_args *vol;
2142         struct btrfs_device *device = NULL;
2143         dev_t devt = 0;
2144         int ret = -ENOTTY;
2145
2146         if (!capable(CAP_SYS_ADMIN))
2147                 return -EPERM;
2148
2149         vol = memdup_user((void __user *)arg, sizeof(*vol));
2150         if (IS_ERR(vol))
2151                 return PTR_ERR(vol);
2152         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2153
2154         switch (cmd) {
2155         case BTRFS_IOC_SCAN_DEV:
2156                 mutex_lock(&uuid_mutex);
2157                 /*
2158                  * Scanning outside of mount can return NULL which would turn
2159                  * into 0 error code.
2160                  */
2161                 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
2162                 ret = PTR_ERR_OR_ZERO(device);
2163                 mutex_unlock(&uuid_mutex);
2164                 break;
2165         case BTRFS_IOC_FORGET_DEV:
2166                 if (vol->name[0] != 0) {
2167                         ret = lookup_bdev(vol->name, &devt);
2168                         if (ret)
2169                                 break;
2170                 }
2171                 ret = btrfs_forget_devices(devt);
2172                 break;
2173         case BTRFS_IOC_DEVICES_READY:
2174                 mutex_lock(&uuid_mutex);
2175                 /*
2176                  * Scanning outside of mount can return NULL which would turn
2177                  * into 0 error code.
2178                  */
2179                 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
2180                 if (IS_ERR_OR_NULL(device)) {
2181                         mutex_unlock(&uuid_mutex);
2182                         ret = PTR_ERR(device);
2183                         break;
2184                 }
2185                 ret = !(device->fs_devices->num_devices ==
2186                         device->fs_devices->total_devices);
2187                 mutex_unlock(&uuid_mutex);
2188                 break;
2189         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2190                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2191                 break;
2192         }
2193
2194         kfree(vol);
2195         return ret;
2196 }
2197
2198 static int btrfs_freeze(struct super_block *sb)
2199 {
2200         struct btrfs_trans_handle *trans;
2201         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2202         struct btrfs_root *root = fs_info->tree_root;
2203
2204         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2205         /*
2206          * We don't need a barrier here, we'll wait for any transaction that
2207          * could be in progress on other threads (and do delayed iputs that
2208          * we want to avoid on a frozen filesystem), or do the commit
2209          * ourselves.
2210          */
2211         trans = btrfs_attach_transaction_barrier(root);
2212         if (IS_ERR(trans)) {
2213                 /* no transaction, don't bother */
2214                 if (PTR_ERR(trans) == -ENOENT)
2215                         return 0;
2216                 return PTR_ERR(trans);
2217         }
2218         return btrfs_commit_transaction(trans);
2219 }
2220
2221 static int check_dev_super(struct btrfs_device *dev)
2222 {
2223         struct btrfs_fs_info *fs_info = dev->fs_info;
2224         struct btrfs_super_block *sb;
2225         u64 last_trans;
2226         u16 csum_type;
2227         int ret = 0;
2228
2229         /* This should be called with fs still frozen. */
2230         ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2231
2232         /* Missing dev, no need to check. */
2233         if (!dev->bdev)
2234                 return 0;
2235
2236         /* Only need to check the primary super block. */
2237         sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2238         if (IS_ERR(sb))
2239                 return PTR_ERR(sb);
2240
2241         /* Verify the checksum. */
2242         csum_type = btrfs_super_csum_type(sb);
2243         if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2244                 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2245                           csum_type, btrfs_super_csum_type(fs_info->super_copy));
2246                 ret = -EUCLEAN;
2247                 goto out;
2248         }
2249
2250         if (btrfs_check_super_csum(fs_info, sb)) {
2251                 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2252                 ret = -EUCLEAN;
2253                 goto out;
2254         }
2255
2256         /* Btrfs_validate_super() includes fsid check against super->fsid. */
2257         ret = btrfs_validate_super(fs_info, sb, 0);
2258         if (ret < 0)
2259                 goto out;
2260
2261         last_trans = btrfs_get_last_trans_committed(fs_info);
2262         if (btrfs_super_generation(sb) != last_trans) {
2263                 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2264                           btrfs_super_generation(sb), last_trans);
2265                 ret = -EUCLEAN;
2266                 goto out;
2267         }
2268 out:
2269         btrfs_release_disk_super(sb);
2270         return ret;
2271 }
2272
2273 static int btrfs_unfreeze(struct super_block *sb)
2274 {
2275         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2276         struct btrfs_device *device;
2277         int ret = 0;
2278
2279         /*
2280          * Make sure the fs is not changed by accident (like hibernation then
2281          * modified by other OS).
2282          * If we found anything wrong, we mark the fs error immediately.
2283          *
2284          * And since the fs is frozen, no one can modify the fs yet, thus
2285          * we don't need to hold device_list_mutex.
2286          */
2287         list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2288                 ret = check_dev_super(device);
2289                 if (ret < 0) {
2290                         btrfs_handle_fs_error(fs_info, ret,
2291                                 "super block on devid %llu got modified unexpectedly",
2292                                 device->devid);
2293                         break;
2294                 }
2295         }
2296         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2297
2298         /*
2299          * We still return 0, to allow VFS layer to unfreeze the fs even the
2300          * above checks failed. Since the fs is either fine or read-only, we're
2301          * safe to continue, without causing further damage.
2302          */
2303         return 0;
2304 }
2305
2306 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2307 {
2308         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2309
2310         /*
2311          * There should be always a valid pointer in latest_dev, it may be stale
2312          * for a short moment in case it's being deleted but still valid until
2313          * the end of RCU grace period.
2314          */
2315         rcu_read_lock();
2316         seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2317         rcu_read_unlock();
2318
2319         return 0;
2320 }
2321
2322 static const struct super_operations btrfs_super_ops = {
2323         .drop_inode     = btrfs_drop_inode,
2324         .evict_inode    = btrfs_evict_inode,
2325         .put_super      = btrfs_put_super,
2326         .sync_fs        = btrfs_sync_fs,
2327         .show_options   = btrfs_show_options,
2328         .show_devname   = btrfs_show_devname,
2329         .alloc_inode    = btrfs_alloc_inode,
2330         .destroy_inode  = btrfs_destroy_inode,
2331         .free_inode     = btrfs_free_inode,
2332         .statfs         = btrfs_statfs,
2333         .remount_fs     = btrfs_remount,
2334         .freeze_fs      = btrfs_freeze,
2335         .unfreeze_fs    = btrfs_unfreeze,
2336 };
2337
2338 static const struct file_operations btrfs_ctl_fops = {
2339         .open = btrfs_control_open,
2340         .unlocked_ioctl  = btrfs_control_ioctl,
2341         .compat_ioctl = compat_ptr_ioctl,
2342         .owner   = THIS_MODULE,
2343         .llseek = noop_llseek,
2344 };
2345
2346 static struct miscdevice btrfs_misc = {
2347         .minor          = BTRFS_MINOR,
2348         .name           = "btrfs-control",
2349         .fops           = &btrfs_ctl_fops
2350 };
2351
2352 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2353 MODULE_ALIAS("devname:btrfs-control");
2354
2355 static int __init btrfs_interface_init(void)
2356 {
2357         return misc_register(&btrfs_misc);
2358 }
2359
2360 static __cold void btrfs_interface_exit(void)
2361 {
2362         misc_deregister(&btrfs_misc);
2363 }
2364
2365 static int __init btrfs_print_mod_info(void)
2366 {
2367         static const char options[] = ""
2368 #ifdef CONFIG_BTRFS_DEBUG
2369                         ", debug=on"
2370 #endif
2371 #ifdef CONFIG_BTRFS_ASSERT
2372                         ", assert=on"
2373 #endif
2374 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2375                         ", ref-verify=on"
2376 #endif
2377 #ifdef CONFIG_BLK_DEV_ZONED
2378                         ", zoned=yes"
2379 #else
2380                         ", zoned=no"
2381 #endif
2382 #ifdef CONFIG_FS_VERITY
2383                         ", fsverity=yes"
2384 #else
2385                         ", fsverity=no"
2386 #endif
2387                         ;
2388         pr_info("Btrfs loaded%s\n", options);
2389         return 0;
2390 }
2391
2392 static int register_btrfs(void)
2393 {
2394         return register_filesystem(&btrfs_fs_type);
2395 }
2396
2397 static void unregister_btrfs(void)
2398 {
2399         unregister_filesystem(&btrfs_fs_type);
2400 }
2401
2402 /* Helper structure for long init/exit functions. */
2403 struct init_sequence {
2404         int (*init_func)(void);
2405         /* Can be NULL if the init_func doesn't need cleanup. */
2406         void (*exit_func)(void);
2407 };
2408
2409 static const struct init_sequence mod_init_seq[] = {
2410         {
2411                 .init_func = btrfs_props_init,
2412                 .exit_func = NULL,
2413         }, {
2414                 .init_func = btrfs_init_sysfs,
2415                 .exit_func = btrfs_exit_sysfs,
2416         }, {
2417                 .init_func = btrfs_init_compress,
2418                 .exit_func = btrfs_exit_compress,
2419         }, {
2420                 .init_func = btrfs_init_cachep,
2421                 .exit_func = btrfs_destroy_cachep,
2422         }, {
2423                 .init_func = btrfs_transaction_init,
2424                 .exit_func = btrfs_transaction_exit,
2425         }, {
2426                 .init_func = btrfs_ctree_init,
2427                 .exit_func = btrfs_ctree_exit,
2428         }, {
2429                 .init_func = btrfs_free_space_init,
2430                 .exit_func = btrfs_free_space_exit,
2431         }, {
2432                 .init_func = extent_state_init_cachep,
2433                 .exit_func = extent_state_free_cachep,
2434         }, {
2435                 .init_func = extent_buffer_init_cachep,
2436                 .exit_func = extent_buffer_free_cachep,
2437         }, {
2438                 .init_func = btrfs_bioset_init,
2439                 .exit_func = btrfs_bioset_exit,
2440         }, {
2441                 .init_func = extent_map_init,
2442                 .exit_func = extent_map_exit,
2443         }, {
2444                 .init_func = ordered_data_init,
2445                 .exit_func = ordered_data_exit,
2446         }, {
2447                 .init_func = btrfs_delayed_inode_init,
2448                 .exit_func = btrfs_delayed_inode_exit,
2449         }, {
2450                 .init_func = btrfs_auto_defrag_init,
2451                 .exit_func = btrfs_auto_defrag_exit,
2452         }, {
2453                 .init_func = btrfs_delayed_ref_init,
2454                 .exit_func = btrfs_delayed_ref_exit,
2455         }, {
2456                 .init_func = btrfs_prelim_ref_init,
2457                 .exit_func = btrfs_prelim_ref_exit,
2458         }, {
2459                 .init_func = btrfs_interface_init,
2460                 .exit_func = btrfs_interface_exit,
2461         }, {
2462                 .init_func = btrfs_print_mod_info,
2463                 .exit_func = NULL,
2464         }, {
2465                 .init_func = btrfs_run_sanity_tests,
2466                 .exit_func = NULL,
2467         }, {
2468                 .init_func = register_btrfs,
2469                 .exit_func = unregister_btrfs,
2470         }
2471 };
2472
2473 static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2474
2475 static __always_inline void btrfs_exit_btrfs_fs(void)
2476 {
2477         int i;
2478
2479         for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2480                 if (!mod_init_result[i])
2481                         continue;
2482                 if (mod_init_seq[i].exit_func)
2483                         mod_init_seq[i].exit_func();
2484                 mod_init_result[i] = false;
2485         }
2486 }
2487
2488 static void __exit exit_btrfs_fs(void)
2489 {
2490         btrfs_exit_btrfs_fs();
2491         btrfs_cleanup_fs_uuids();
2492 }
2493
2494 static int __init init_btrfs_fs(void)
2495 {
2496         int ret;
2497         int i;
2498
2499         for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2500                 ASSERT(!mod_init_result[i]);
2501                 ret = mod_init_seq[i].init_func();
2502                 if (ret < 0) {
2503                         btrfs_exit_btrfs_fs();
2504                         return ret;
2505                 }
2506                 mod_init_result[i] = true;
2507         }
2508         return 0;
2509 }
2510
2511 late_initcall(init_btrfs_fs);
2512 module_exit(exit_btrfs_fs)
2513
2514 MODULE_LICENSE("GPL");
2515 MODULE_SOFTDEP("pre: crc32c");
2516 MODULE_SOFTDEP("pre: xxhash64");
2517 MODULE_SOFTDEP("pre: sha256");
2518 MODULE_SOFTDEP("pre: blake2b-256");