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 "messages.h"
  30 #include "delayed-inode.h"
  31 #include "ctree.h"
  32 #include "disk-io.h"
  33 #include "transaction.h"
  34 #include "btrfs_inode.h"
  35 #include "print-tree.h"
  36 #include "props.h"
  37 #include "xattr.h"
  38 #include "volumes.h"
  39 #include "export.h"
  40 #include "compression.h"
  41 #include "rcu-string.h"
  42 #include "dev-replace.h"
  43 #include "free-space-cache.h"
  44 #include "backref.h"
  45 #include "space-info.h"
  46 #include "sysfs.h"
  47 #include "zoned.h"
  48 #include "tests/btrfs-tests.h"
  49 #include "block-group.h"
  50 #include "discard.h"
  51 #include "qgroup.h"
  52 #include "raid56.h"
  53 #include "fs.h"
  54 #include "accessors.h"
  55 #include "defrag.h"
  56 #include "dir-item.h"
  57 #include "ioctl.h"
  58 #include "scrub.h"
  59 #include "verity.h"
  60 #include "super.h"
  61 #define CREATE_TRACE_POINTS
  62 #include <trace/events/btrfs.h>
  63
  64 static const struct super_operations btrfs_super_ops;
  65
  66 /*
  67  * Types for mounting the default subvolume and a subvolume explicitly
  68  * requested by subvol=/path. That way the callchain is straightforward and we
  69  * don't have to play tricks with the mount options and recursive calls to
  70  * btrfs_mount.
  71  *
  72  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
  73  */
  74 static struct file_system_type btrfs_fs_type;
  75 static struct file_system_type btrfs_root_fs_type;
  76
  77 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  78
  79 static void btrfs_put_super(struct super_block *sb)
  80 {
  81         close_ctree(btrfs_sb(sb));
  82 }
  83
  84 enum {
  85         Opt_acl, Opt_noacl,
  86         Opt_clear_cache,
  87         Opt_commit_interval,
  88         Opt_compress,
  89         Opt_compress_force,
  90         Opt_compress_force_type,
  91         Opt_compress_type,
  92         Opt_degraded,
  93         Opt_device,
  94         Opt_fatal_errors,
  95         Opt_flushoncommit, Opt_noflushoncommit,
  96         Opt_max_inline,
  97         Opt_barrier, Opt_nobarrier,
  98         Opt_datacow, Opt_nodatacow,
  99         Opt_datasum, Opt_nodatasum,
 100         Opt_defrag, Opt_nodefrag,
 101         Opt_discard, Opt_nodiscard,
 102         Opt_discard_mode,
 103         Opt_norecovery,
 104         Opt_ratio,
 105         Opt_rescan_uuid_tree,
 106         Opt_skip_balance,
 107         Opt_space_cache, Opt_no_space_cache,
 108         Opt_space_cache_version,
 109         Opt_ssd, Opt_nossd,
 110         Opt_ssd_spread, Opt_nossd_spread,
 111         Opt_subvol,
 112         Opt_subvol_empty,
 113         Opt_subvolid,
 114         Opt_thread_pool,
 115         Opt_treelog, Opt_notreelog,
 116         Opt_user_subvol_rm_allowed,
 117
 118         /* Rescue options */
 119         Opt_rescue,
 120         Opt_usebackuproot,
 121         Opt_nologreplay,
 122         Opt_ignorebadroots,
 123         Opt_ignoredatacsums,
 124         Opt_rescue_all,
 125
 126         /* Deprecated options */
 127         Opt_recovery,
 128         Opt_inode_cache, Opt_noinode_cache,
 129
 130         /* Debugging options */
 131         Opt_check_integrity,
 132         Opt_check_integrity_including_extent_data,
 133         Opt_check_integrity_print_mask,
 134         Opt_enospc_debug, Opt_noenospc_debug,
 135 #ifdef CONFIG_BTRFS_DEBUG
 136         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 137 #endif
 138 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 139         Opt_ref_verify,
 140 #endif
 141         Opt_err,
 142 };
 143
 144 static const match_table_t tokens = {
 145         {Opt_acl, "acl"},
 146         {Opt_noacl, "noacl"},
 147         {Opt_clear_cache, "clear_cache"},
 148         {Opt_commit_interval, "commit=%u"},
 149         {Opt_compress, "compress"},
 150         {Opt_compress_type, "compress=%s"},
 151         {Opt_compress_force, "compress-force"},
 152         {Opt_compress_force_type, "compress-force=%s"},
 153         {Opt_degraded, "degraded"},
 154         {Opt_device, "device=%s"},
 155         {Opt_fatal_errors, "fatal_errors=%s"},
 156         {Opt_flushoncommit, "flushoncommit"},
 157         {Opt_noflushoncommit, "noflushoncommit"},
 158         {Opt_inode_cache, "inode_cache"},
 159         {Opt_noinode_cache, "noinode_cache"},
 160         {Opt_max_inline, "max_inline=%s"},
 161         {Opt_barrier, "barrier"},
 162         {Opt_nobarrier, "nobarrier"},
 163         {Opt_datacow, "datacow"},
 164         {Opt_nodatacow, "nodatacow"},
 165         {Opt_datasum, "datasum"},
 166         {Opt_nodatasum, "nodatasum"},
 167         {Opt_defrag, "autodefrag"},
 168         {Opt_nodefrag, "noautodefrag"},
 169         {Opt_discard, "discard"},
 170         {Opt_discard_mode, "discard=%s"},
 171         {Opt_nodiscard, "nodiscard"},
 172         {Opt_norecovery, "norecovery"},
 173         {Opt_ratio, "metadata_ratio=%u"},
 174         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 175         {Opt_skip_balance, "skip_balance"},
 176         {Opt_space_cache, "space_cache"},
 177         {Opt_no_space_cache, "nospace_cache"},
 178         {Opt_space_cache_version, "space_cache=%s"},
 179         {Opt_ssd, "ssd"},
 180         {Opt_nossd, "nossd"},
 181         {Opt_ssd_spread, "ssd_spread"},
 182         {Opt_nossd_spread, "nossd_spread"},
 183         {Opt_subvol, "subvol=%s"},
 184         {Opt_subvol_empty, "subvol="},
 185         {Opt_subvolid, "subvolid=%s"},
 186         {Opt_thread_pool, "thread_pool=%u"},
 187         {Opt_treelog, "treelog"},
 188         {Opt_notreelog, "notreelog"},
 189         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 190
 191         /* Rescue options */
 192         {Opt_rescue, "rescue=%s"},
 193         /* Deprecated, with alias rescue=nologreplay */
 194         {Opt_nologreplay, "nologreplay"},
 195         /* Deprecated, with alias rescue=usebackuproot */
 196         {Opt_usebackuproot, "usebackuproot"},
 197
 198         /* Deprecated options */
 199         {Opt_recovery, "recovery"},
 200
 201         /* Debugging options */
 202         {Opt_check_integrity, "check_int"},
 203         {Opt_check_integrity_including_extent_data, "check_int_data"},
 204         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
 205         {Opt_enospc_debug, "enospc_debug"},
 206         {Opt_noenospc_debug, "noenospc_debug"},
 207 #ifdef CONFIG_BTRFS_DEBUG
 208         {Opt_fragment_data, "fragment=data"},
 209         {Opt_fragment_metadata, "fragment=metadata"},
 210         {Opt_fragment_all, "fragment=all"},
 211 #endif
 212 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 213         {Opt_ref_verify, "ref_verify"},
 214 #endif
 215         {Opt_err, NULL},
 216 };
 217
 218 static const match_table_t rescue_tokens = {
 219         {Opt_usebackuproot, "usebackuproot"},
 220         {Opt_nologreplay, "nologreplay"},
 221         {Opt_ignorebadroots, "ignorebadroots"},
 222         {Opt_ignorebadroots, "ibadroots"},
 223         {Opt_ignoredatacsums, "ignoredatacsums"},
 224         {Opt_ignoredatacsums, "idatacsums"},
 225         {Opt_rescue_all, "all"},
 226         {Opt_err, NULL},
 227 };
 228
 229 static bool check_ro_option(struct btrfs_fs_info *fs_info, unsigned long opt,
 230                             const char *opt_name)
 231 {
 232         if (fs_info->mount_opt & opt) {
 233                 btrfs_err(fs_info, "%s must be used with ro mount option",
 234                           opt_name);
 235                 return true;
 236         }
 237         return false;
 238 }
 239
 240 static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
 241 {
 242         char *opts;
 243         char *orig;
 244         char *p;
 245         substring_t args[MAX_OPT_ARGS];
 246         int ret = 0;
 247
 248         opts = kstrdup(options, GFP_KERNEL);
 249         if (!opts)
 250                 return -ENOMEM;
 251         orig = opts;
 252
 253         while ((p = strsep(&opts, ":")) != NULL) {
 254                 int token;
 255
 256                 if (!*p)
 257                         continue;
 258                 token = match_token(p, rescue_tokens, args);
 259                 switch (token){
 260                 case Opt_usebackuproot:
 261                         btrfs_info(info,
 262                                    "trying to use backup root at mount time");
 263                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 264                         break;
 265                 case Opt_nologreplay:
 266                         btrfs_set_and_info(info, NOLOGREPLAY,
 267                                            "disabling log replay at mount time");
 268                         break;
 269                 case Opt_ignorebadroots:
 270                         btrfs_set_and_info(info, IGNOREBADROOTS,
 271                                            "ignoring bad roots");
 272                         break;
 273                 case Opt_ignoredatacsums:
 274                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 275                                            "ignoring data csums");
 276                         break;
 277                 case Opt_rescue_all:
 278                         btrfs_info(info, "enabling all of the rescue options");
 279                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 280                                            "ignoring data csums");
 281                         btrfs_set_and_info(info, IGNOREBADROOTS,
 282                                            "ignoring bad roots");
 283                         btrfs_set_and_info(info, NOLOGREPLAY,
 284                                            "disabling log replay at mount time");
 285                         break;
 286                 case Opt_err:
 287                         btrfs_info(info, "unrecognized rescue option '%s'", p);
 288                         ret = -EINVAL;
 289                         goto out;
 290                 default:
 291                         break;
 292                 }
 293
 294         }
 295 out:
 296         kfree(orig);
 297         return ret;
 298 }
 299
 300 /*
 301  * Regular mount options parser.  Everything that is needed only when
 302  * reading in a new superblock is parsed here.
 303  * XXX JDM: This needs to be cleaned up for remount.
 304  */
 305 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 306                         unsigned long new_flags)
 307 {
 308         substring_t args[MAX_OPT_ARGS];
 309         char *p, *num;
 310         int intarg;
 311         int ret = 0;
 312         char *compress_type;
 313         bool compress_force = false;
 314         enum btrfs_compression_type saved_compress_type;
 315         int saved_compress_level;
 316         bool saved_compress_force;
 317         int no_compress = 0;
 318         const bool remounting = test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state);
 319
 320         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 321                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 322         else if (btrfs_free_space_cache_v1_active(info)) {
 323                 if (btrfs_is_zoned(info)) {
 324                         btrfs_info(info,
 325                         "zoned: clearing existing space cache");
 326                         btrfs_set_super_cache_generation(info->super_copy, 0);
 327                 } else {
 328                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 329                 }
 330         }
 331
 332         /*
 333          * Even the options are empty, we still need to do extra check
 334          * against new flags
 335          */
 336         if (!options)
 337                 goto check;
 338
 339         while ((p = strsep(&options, ",")) != NULL) {
 340                 int token;
 341                 if (!*p)
 342                         continue;
 343
 344                 token = match_token(p, tokens, args);
 345                 switch (token) {
 346                 case Opt_degraded:
 347                         btrfs_info(info, "allowing degraded mounts");
 348                         btrfs_set_opt(info->mount_opt, DEGRADED);
 349                         break;
 350                 case Opt_subvol:
 351                 case Opt_subvol_empty:
 352                 case Opt_subvolid:
 353                 case Opt_device:
 354                         /*
 355                          * These are parsed by btrfs_parse_subvol_options or
 356                          * btrfs_parse_device_options and can be ignored here.
 357                          */
 358                         break;
 359                 case Opt_nodatasum:
 360                         btrfs_set_and_info(info, NODATASUM,
 361                                            "setting nodatasum");
 362                         break;
 363                 case Opt_datasum:
 364                         if (btrfs_test_opt(info, NODATASUM)) {
 365                                 if (btrfs_test_opt(info, NODATACOW))
 366                                         btrfs_info(info,
 367                                                    "setting datasum, datacow enabled");
 368                                 else
 369                                         btrfs_info(info, "setting datasum");
 370                         }
 371                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 372                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 373                         break;
 374                 case Opt_nodatacow:
 375                         if (!btrfs_test_opt(info, NODATACOW)) {
 376                                 if (!btrfs_test_opt(info, COMPRESS) ||
 377                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 378                                         btrfs_info(info,
 379                                                    "setting nodatacow, compression disabled");
 380                                 } else {
 381                                         btrfs_info(info, "setting nodatacow");
 382                                 }
 383                         }
 384                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 385                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 386                         btrfs_set_opt(info->mount_opt, NODATACOW);
 387                         btrfs_set_opt(info->mount_opt, NODATASUM);
 388                         break;
 389                 case Opt_datacow:
 390                         btrfs_clear_and_info(info, NODATACOW,
 391                                              "setting datacow");
 392                         break;
 393                 case Opt_compress_force:
 394                 case Opt_compress_force_type:
 395                         compress_force = true;
 396                         fallthrough;
 397                 case Opt_compress:
 398                 case Opt_compress_type:
 399                         saved_compress_type = btrfs_test_opt(info,
 400                                                              COMPRESS) ?
 401                                 info->compress_type : BTRFS_COMPRESS_NONE;
 402                         saved_compress_force =
 403                                 btrfs_test_opt(info, FORCE_COMPRESS);
 404                         saved_compress_level = info->compress_level;
 405                         if (token == Opt_compress ||
 406                             token == Opt_compress_force ||
 407                             strncmp(args[0].from, "zlib", 4) == 0) {
 408                                 compress_type = "zlib";
 409
 410                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 411                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 412                                 /*
 413                                  * args[0] contains uninitialized data since
 414                                  * for these tokens we don't expect any
 415                                  * parameter.
 416                                  */
 417                                 if (token != Opt_compress &&
 418                                     token != Opt_compress_force)
 419                                         info->compress_level =
 420                                           btrfs_compress_str2level(
 421                                                         BTRFS_COMPRESS_ZLIB,
 422                                                         args[0].from + 4);
 423                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 424                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 425                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 426                                 no_compress = 0;
 427                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 428                                 compress_type = "lzo";
 429                                 info->compress_type = BTRFS_COMPRESS_LZO;
 430                                 info->compress_level = 0;
 431                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 432                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 433                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 434                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 435                                 no_compress = 0;
 436                         } else if (strncmp(args[0].from, "zstd", 4) == 0) {
 437                                 compress_type = "zstd";
 438                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 439                                 info->compress_level =
 440                                         btrfs_compress_str2level(
 441                                                          BTRFS_COMPRESS_ZSTD,
 442                                                          args[0].from + 4);
 443                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 444                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 445                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 446                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 447                                 no_compress = 0;
 448                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 449                                 compress_type = "no";
 450                                 info->compress_level = 0;
 451                                 info->compress_type = 0;
 452                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 453                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 454                                 compress_force = false;
 455                                 no_compress++;
 456                         } else {
 457                                 btrfs_err(info, "unrecognized compression value %s",
 458                                           args[0].from);
 459                                 ret = -EINVAL;
 460                                 goto out;
 461                         }
 462
 463                         if (compress_force) {
 464                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 465                         } else {
 466                                 /*
 467                                  * If we remount from compress-force=xxx to
 468                                  * compress=xxx, we need clear FORCE_COMPRESS
 469                                  * flag, otherwise, there is no way for users
 470                                  * to disable forcible compression separately.
 471                                  */
 472                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 473                         }
 474                         if (no_compress == 1) {
 475                                 btrfs_info(info, "use no compression");
 476                         } else if ((info->compress_type != saved_compress_type) ||
 477                                    (compress_force != saved_compress_force) ||
 478                                    (info->compress_level != saved_compress_level)) {
 479                                 btrfs_info(info, "%s %s compression, level %d",
 480                                            (compress_force) ? "force" : "use",
 481                                            compress_type, info->compress_level);
 482                         }
 483                         compress_force = false;
 484                         break;
 485                 case Opt_ssd:
 486                         btrfs_set_and_info(info, SSD,
 487                                            "enabling ssd optimizations");
 488                         btrfs_clear_opt(info->mount_opt, NOSSD);
 489                         break;
 490                 case Opt_ssd_spread:
 491                         btrfs_set_and_info(info, SSD,
 492                                            "enabling ssd optimizations");
 493                         btrfs_set_and_info(info, SSD_SPREAD,
 494                                            "using spread ssd allocation scheme");
 495                         btrfs_clear_opt(info->mount_opt, NOSSD);
 496                         break;
 497                 case Opt_nossd:
 498                         btrfs_set_opt(info->mount_opt, NOSSD);
 499                         btrfs_clear_and_info(info, SSD,
 500                                              "not using ssd optimizations");
 501                         fallthrough;
 502                 case Opt_nossd_spread:
 503                         btrfs_clear_and_info(info, SSD_SPREAD,
 504                                              "not using spread ssd allocation scheme");
 505                         break;
 506                 case Opt_barrier:
 507                         btrfs_clear_and_info(info, NOBARRIER,
 508                                              "turning on barriers");
 509                         break;
 510                 case Opt_nobarrier:
 511                         btrfs_set_and_info(info, NOBARRIER,
 512                                            "turning off barriers");
 513                         break;
 514                 case Opt_thread_pool:
 515                         ret = match_int(&args[0], &intarg);
 516                         if (ret) {
 517                                 btrfs_err(info, "unrecognized thread_pool value %s",
 518                                           args[0].from);
 519                                 goto out;
 520                         } else if (intarg == 0) {
 521                                 btrfs_err(info, "invalid value 0 for thread_pool");
 522                                 ret = -EINVAL;
 523                                 goto out;
 524                         }
 525                         info->thread_pool_size = intarg;
 526                         break;
 527                 case Opt_max_inline:
 528                         num = match_strdup(&args[0]);
 529                         if (num) {
 530                                 info->max_inline = memparse(num, NULL);
 531                                 kfree(num);
 532
 533                                 if (info->max_inline) {
 534                                         info->max_inline = min_t(u64,
 535                                                 info->max_inline,
 536                                                 info->sectorsize);
 537                                 }
 538                                 btrfs_info(info, "max_inline at %llu",
 539                                            info->max_inline);
 540                         } else {
 541                                 ret = -ENOMEM;
 542                                 goto out;
 543                         }
 544                         break;
 545                 case Opt_acl:
 546 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 547                         info->sb->s_flags |= SB_POSIXACL;
 548                         break;
 549 #else
 550                         btrfs_err(info, "support for ACL not compiled in!");
 551                         ret = -EINVAL;
 552                         goto out;
 553 #endif
 554                 case Opt_noacl:
 555                         info->sb->s_flags &= ~SB_POSIXACL;
 556                         break;
 557                 case Opt_notreelog:
 558                         btrfs_set_and_info(info, NOTREELOG,
 559                                            "disabling tree log");
 560                         break;
 561                 case Opt_treelog:
 562                         btrfs_clear_and_info(info, NOTREELOG,
 563                                              "enabling tree log");
 564                         break;
 565                 case Opt_norecovery:
 566                 case Opt_nologreplay:
 567                         btrfs_warn(info,
 568                 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
 569                         btrfs_set_and_info(info, NOLOGREPLAY,
 570                                            "disabling log replay at mount time");
 571                         break;
 572                 case Opt_flushoncommit:
 573                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 574                                            "turning on flush-on-commit");
 575                         break;
 576                 case Opt_noflushoncommit:
 577                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 578                                              "turning off flush-on-commit");
 579                         break;
 580                 case Opt_ratio:
 581                         ret = match_int(&args[0], &intarg);
 582                         if (ret) {
 583                                 btrfs_err(info, "unrecognized metadata_ratio value %s",
 584                                           args[0].from);
 585                                 goto out;
 586                         }
 587                         info->metadata_ratio = intarg;
 588                         btrfs_info(info, "metadata ratio %u",
 589                                    info->metadata_ratio);
 590                         break;
 591                 case Opt_discard:
 592                 case Opt_discard_mode:
 593                         if (token == Opt_discard ||
 594                             strcmp(args[0].from, "sync") == 0) {
 595                                 btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
 596                                 btrfs_set_and_info(info, DISCARD_SYNC,
 597                                                    "turning on sync discard");
 598                         } else if (strcmp(args[0].from, "async") == 0) {
 599                                 btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
 600                                 btrfs_set_and_info(info, DISCARD_ASYNC,
 601                                                    "turning on async discard");
 602                         } else {
 603                                 btrfs_err(info, "unrecognized discard mode value %s",
 604                                           args[0].from);
 605                                 ret = -EINVAL;
 606                                 goto out;
 607                         }
 608                         btrfs_clear_opt(info->mount_opt, NODISCARD);
 609                         break;
 610                 case Opt_nodiscard:
 611                         btrfs_clear_and_info(info, DISCARD_SYNC,
 612                                              "turning off discard");
 613                         btrfs_clear_and_info(info, DISCARD_ASYNC,
 614                                              "turning off async discard");
 615                         btrfs_set_opt(info->mount_opt, NODISCARD);
 616                         break;
 617                 case Opt_space_cache:
 618                 case Opt_space_cache_version:
 619                         /*
 620                          * We already set FREE_SPACE_TREE above because we have
 621                          * compat_ro(FREE_SPACE_TREE) set, and we aren't going
 622                          * to allow v1 to be set for extent tree v2, simply
 623                          * ignore this setting if we're extent tree v2.
 624                          */
 625                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 626                                 break;
 627                         if (token == Opt_space_cache ||
 628                             strcmp(args[0].from, "v1") == 0) {
 629                                 btrfs_clear_opt(info->mount_opt,
 630                                                 FREE_SPACE_TREE);
 631                                 btrfs_set_and_info(info, SPACE_CACHE,
 632                                            "enabling disk space caching");
 633                         } else if (strcmp(args[0].from, "v2") == 0) {
 634                                 btrfs_clear_opt(info->mount_opt,
 635                                                 SPACE_CACHE);
 636                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 637                                                    "enabling free space tree");
 638                         } else {
 639                                 btrfs_err(info, "unrecognized space_cache value %s",
 640                                           args[0].from);
 641                                 ret = -EINVAL;
 642                                 goto out;
 643                         }
 644                         break;
 645                 case Opt_rescan_uuid_tree:
 646                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 647                         break;
 648                 case Opt_no_space_cache:
 649                         /*
 650                          * We cannot operate without the free space tree with
 651                          * extent tree v2, ignore this option.
 652                          */
 653                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 654                                 break;
 655                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 656                                 btrfs_clear_and_info(info, SPACE_CACHE,
 657                                              "disabling disk space caching");
 658                         }
 659                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 660                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 661                                              "disabling free space tree");
 662                         }
 663                         break;
 664                 case Opt_inode_cache:
 665                 case Opt_noinode_cache:
 666                         btrfs_warn(info,
 667         "the 'inode_cache' option is deprecated and has no effect since 5.11");
 668                         break;
 669                 case Opt_clear_cache:
 670                         /*
 671                          * We cannot clear the free space tree with extent tree
 672                          * v2, ignore this option.
 673                          */
 674                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 675                                 break;
 676                         btrfs_set_and_info(info, CLEAR_CACHE,
 677                                            "force clearing of disk cache");
 678                         break;
 679                 case Opt_user_subvol_rm_allowed:
 680                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 681                         break;
 682                 case Opt_enospc_debug:
 683                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 684                         break;
 685                 case Opt_noenospc_debug:
 686                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 687                         break;
 688                 case Opt_defrag:
 689                         btrfs_set_and_info(info, AUTO_DEFRAG,
 690                                            "enabling auto defrag");
 691                         break;
 692                 case Opt_nodefrag:
 693                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 694                                              "disabling auto defrag");
 695                         break;
 696                 case Opt_recovery:
 697                 case Opt_usebackuproot:
 698                         btrfs_warn(info,
 699                         "'%s' is deprecated, use 'rescue=usebackuproot' instead",
 700                                    token == Opt_recovery ? "recovery" :
 701                                    "usebackuproot");
 702                         btrfs_info(info,
 703                                    "trying to use backup root at mount time");
 704                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 705                         break;
 706                 case Opt_skip_balance:
 707                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 708                         break;
 709 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 710                 case Opt_check_integrity_including_extent_data:
 711                         btrfs_info(info,
 712                                    "enabling check integrity including extent data");
 713                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY_DATA);
 714                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 715                         break;
 716                 case Opt_check_integrity:
 717                         btrfs_info(info, "enabling check integrity");
 718                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 719                         break;
 720                 case Opt_check_integrity_print_mask:
 721                         ret = match_int(&args[0], &intarg);
 722                         if (ret) {
 723                                 btrfs_err(info,
 724                                 "unrecognized check_integrity_print_mask value %s",
 725                                         args[0].from);
 726                                 goto out;
 727                         }
 728                         info->check_integrity_print_mask = intarg;
 729                         btrfs_info(info, "check_integrity_print_mask 0x%x",
 730                                    info->check_integrity_print_mask);
 731                         break;
 732 #else
 733                 case Opt_check_integrity_including_extent_data:
 734                 case Opt_check_integrity:
 735                 case Opt_check_integrity_print_mask:
 736                         btrfs_err(info,
 737                                   "support for check_integrity* not compiled in!");
 738                         ret = -EINVAL;
 739                         goto out;
 740 #endif
 741                 case Opt_fatal_errors:
 742                         if (strcmp(args[0].from, "panic") == 0) {
 743                                 btrfs_set_opt(info->mount_opt,
 744                                               PANIC_ON_FATAL_ERROR);
 745                         } else if (strcmp(args[0].from, "bug") == 0) {
 746                                 btrfs_clear_opt(info->mount_opt,
 747                                               PANIC_ON_FATAL_ERROR);
 748                         } else {
 749                                 btrfs_err(info, "unrecognized fatal_errors value %s",
 750                                           args[0].from);
 751                                 ret = -EINVAL;
 752                                 goto out;
 753                         }
 754                         break;
 755                 case Opt_commit_interval:
 756                         intarg = 0;
 757                         ret = match_int(&args[0], &intarg);
 758                         if (ret) {
 759                                 btrfs_err(info, "unrecognized commit_interval value %s",
 760                                           args[0].from);
 761                                 ret = -EINVAL;
 762                                 goto out;
 763                         }
 764                         if (intarg == 0) {
 765                                 btrfs_info(info,
 766                                            "using default commit interval %us",
 767                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 768                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
 769                         } else if (intarg > 300) {
 770                                 btrfs_warn(info, "excessive commit interval %d",
 771                                            intarg);
 772                         }
 773                         info->commit_interval = intarg;
 774                         break;
 775                 case Opt_rescue:
 776                         ret = parse_rescue_options(info, args[0].from);
 777                         if (ret < 0) {
 778                                 btrfs_err(info, "unrecognized rescue value %s",
 779                                           args[0].from);
 780                                 goto out;
 781                         }
 782                         break;
 783 #ifdef CONFIG_BTRFS_DEBUG
 784                 case Opt_fragment_all:
 785                         btrfs_info(info, "fragmenting all space");
 786                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 787                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 788                         break;
 789                 case Opt_fragment_metadata:
 790                         btrfs_info(info, "fragmenting metadata");
 791                         btrfs_set_opt(info->mount_opt,
 792                                       FRAGMENT_METADATA);
 793                         break;
 794                 case Opt_fragment_data:
 795                         btrfs_info(info, "fragmenting data");
 796                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 797                         break;
 798 #endif
 799 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 800                 case Opt_ref_verify:
 801                         btrfs_info(info, "doing ref verification");
 802                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 803                         break;
 804 #endif
 805                 case Opt_err:
 806                         btrfs_err(info, "unrecognized mount option '%s'", p);
 807                         ret = -EINVAL;
 808                         goto out;
 809                 default:
 810                         break;
 811                 }
 812         }
 813 check:
 814         /* We're read-only, don't have to check. */
 815         if (new_flags & SB_RDONLY)
 816                 goto out;
 817
 818         if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
 819             check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
 820             check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))
 821                 ret = -EINVAL;
 822 out:
 823         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 824             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 825             !btrfs_test_opt(info, CLEAR_CACHE)) {
 826                 btrfs_err(info, "cannot disable free space tree");
 827                 ret = -EINVAL;
 828
 829         }
 830         if (!ret)
 831                 ret = btrfs_check_mountopts_zoned(info);
 832         if (!ret && !remounting) {
 833                 if (btrfs_test_opt(info, SPACE_CACHE))
 834                         btrfs_info(info, "disk space caching is enabled");
 835                 if (btrfs_test_opt(info, FREE_SPACE_TREE))
 836                         btrfs_info(info, "using free space tree");
 837         }
 838         return ret;
 839 }
 840
 841 /*
 842  * Parse mount options that are required early in the mount process.
 843  *
 844  * All other options will be parsed on much later in the mount process and
 845  * only when we need to allocate a new super block.
 846  */
 847 static int btrfs_parse_device_options(const char *options, fmode_t flags,
 848                                       void *holder)
 849 {
 850         substring_t args[MAX_OPT_ARGS];
 851         char *device_name, *opts, *orig, *p;
 852         struct btrfs_device *device = NULL;
 853         int error = 0;
 854
 855         lockdep_assert_held(&uuid_mutex);
 856
 857         if (!options)
 858                 return 0;
 859
 860         /*
 861          * strsep changes the string, duplicate it because btrfs_parse_options
 862          * gets called later
 863          */
 864         opts = kstrdup(options, GFP_KERNEL);
 865         if (!opts)
 866                 return -ENOMEM;
 867         orig = opts;
 868
 869         while ((p = strsep(&opts, ",")) != NULL) {
 870                 int token;
 871
 872                 if (!*p)
 873                         continue;
 874
 875                 token = match_token(p, tokens, args);
 876                 if (token == Opt_device) {
 877                         device_name = match_strdup(&args[0]);
 878                         if (!device_name) {
 879                                 error = -ENOMEM;
 880                                 goto out;
 881                         }
 882                         device = btrfs_scan_one_device(device_name, flags,
 883                                         holder);
 884                         kfree(device_name);
 885                         if (IS_ERR(device)) {
 886                                 error = PTR_ERR(device);
 887                                 goto out;
 888                         }
 889                 }
 890         }
 891
 892 out:
 893         kfree(orig);
 894         return error;
 895 }
 896
 897 /*
 898  * Parse mount options that are related to subvolume id
 899  *
 900  * The value is later passed to mount_subvol()
 901  */
 902 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
 903                 u64 *subvol_objectid)
 904 {
 905         substring_t args[MAX_OPT_ARGS];
 906         char *opts, *orig, *p;
 907         int error = 0;
 908         u64 subvolid;
 909
 910         if (!options)
 911                 return 0;
 912
 913         /*
 914          * strsep changes the string, duplicate it because
 915          * btrfs_parse_device_options gets called later
 916          */
 917         opts = kstrdup(options, GFP_KERNEL);
 918         if (!opts)
 919                 return -ENOMEM;
 920         orig = opts;
 921
 922         while ((p = strsep(&opts, ",")) != NULL) {
 923                 int token;
 924                 if (!*p)
 925                         continue;
 926
 927                 token = match_token(p, tokens, args);
 928                 switch (token) {
 929                 case Opt_subvol:
 930                         kfree(*subvol_name);
 931                         *subvol_name = match_strdup(&args[0]);
 932                         if (!*subvol_name) {
 933                                 error = -ENOMEM;
 934                                 goto out;
 935                         }
 936                         break;
 937                 case Opt_subvolid:
 938                         error = match_u64(&args[0], &subvolid);
 939                         if (error)
 940                                 goto out;
 941
 942                         /* we want the original fs_tree */
 943                         if (subvolid == 0)
 944                                 subvolid = BTRFS_FS_TREE_OBJECTID;
 945
 946                         *subvol_objectid = subvolid;
 947                         break;
 948                 default:
 949                         break;
 950                 }
 951         }
 952
 953 out:
 954         kfree(orig);
 955         return error;
 956 }
 957
 958 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 959                                           u64 subvol_objectid)
 960 {
 961         struct btrfs_root *root = fs_info->tree_root;
 962         struct btrfs_root *fs_root = NULL;
 963         struct btrfs_root_ref *root_ref;
 964         struct btrfs_inode_ref *inode_ref;
 965         struct btrfs_key key;
 966         struct btrfs_path *path = NULL;
 967         char *name = NULL, *ptr;
 968         u64 dirid;
 969         int len;
 970         int ret;
 971
 972         path = btrfs_alloc_path();
 973         if (!path) {
 974                 ret = -ENOMEM;
 975                 goto err;
 976         }
 977
 978         name = kmalloc(PATH_MAX, GFP_KERNEL);
 979         if (!name) {
 980                 ret = -ENOMEM;
 981                 goto err;
 982         }
 983         ptr = name + PATH_MAX - 1;
 984         ptr[0] = '\0';
 985
 986         /*
 987          * Walk up the subvolume trees in the tree of tree roots by root
 988          * backrefs until we hit the top-level subvolume.
 989          */
 990         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 991                 key.objectid = subvol_objectid;
 992                 key.type = BTRFS_ROOT_BACKREF_KEY;
 993                 key.offset = (u64)-1;
 994
 995                 ret = btrfs_search_backwards(root, &key, path);
 996                 if (ret < 0) {
 997                         goto err;
 998                 } else if (ret > 0) {
 999                         ret = -ENOENT;
1000                         goto err;
1001                 }
1002
1003                 subvol_objectid = key.offset;
1004
1005                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1006                                           struct btrfs_root_ref);
1007                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1008                 ptr -= len + 1;
1009                 if (ptr < name) {
1010                         ret = -ENAMETOOLONG;
1011                         goto err;
1012                 }
1013                 read_extent_buffer(path->nodes[0], ptr + 1,
1014                                    (unsigned long)(root_ref + 1), len);
1015                 ptr[0] = '/';
1016                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1017                 btrfs_release_path(path);
1018
1019                 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
1020                 if (IS_ERR(fs_root)) {
1021                         ret = PTR_ERR(fs_root);
1022                         fs_root = NULL;
1023                         goto err;
1024                 }
1025
1026                 /*
1027                  * Walk up the filesystem tree by inode refs until we hit the
1028                  * root directory.
1029                  */
1030                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1031                         key.objectid = dirid;
1032                         key.type = BTRFS_INODE_REF_KEY;
1033                         key.offset = (u64)-1;
1034
1035                         ret = btrfs_search_backwards(fs_root, &key, path);
1036                         if (ret < 0) {
1037                                 goto err;
1038                         } else if (ret > 0) {
1039                                 ret = -ENOENT;
1040                                 goto err;
1041                         }
1042
1043                         dirid = key.offset;
1044
1045                         inode_ref = btrfs_item_ptr(path->nodes[0],
1046                                                    path->slots[0],
1047                                                    struct btrfs_inode_ref);
1048                         len = btrfs_inode_ref_name_len(path->nodes[0],
1049                                                        inode_ref);
1050                         ptr -= len + 1;
1051                         if (ptr < name) {
1052                                 ret = -ENAMETOOLONG;
1053                                 goto err;
1054                         }
1055                         read_extent_buffer(path->nodes[0], ptr + 1,
1056                                            (unsigned long)(inode_ref + 1), len);
1057                         ptr[0] = '/';
1058                         btrfs_release_path(path);
1059                 }
1060                 btrfs_put_root(fs_root);
1061                 fs_root = NULL;
1062         }
1063
1064         btrfs_free_path(path);
1065         if (ptr == name + PATH_MAX - 1) {
1066                 name[0] = '/';
1067                 name[1] = '\0';
1068         } else {
1069                 memmove(name, ptr, name + PATH_MAX - ptr);
1070         }
1071         return name;
1072
1073 err:
1074         btrfs_put_root(fs_root);
1075         btrfs_free_path(path);
1076         kfree(name);
1077         return ERR_PTR(ret);
1078 }
1079
1080 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1081 {
1082         struct btrfs_root *root = fs_info->tree_root;
1083         struct btrfs_dir_item *di;
1084         struct btrfs_path *path;
1085         struct btrfs_key location;
1086         struct fscrypt_str name = FSTR_INIT("default", 7);
1087         u64 dir_id;
1088
1089         path = btrfs_alloc_path();
1090         if (!path)
1091                 return -ENOMEM;
1092
1093         /*
1094          * Find the "default" dir item which points to the root item that we
1095          * will mount by default if we haven't been given a specific subvolume
1096          * to mount.
1097          */
1098         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1099         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
1100         if (IS_ERR(di)) {
1101                 btrfs_free_path(path);
1102                 return PTR_ERR(di);
1103         }
1104         if (!di) {
1105                 /*
1106                  * Ok the default dir item isn't there.  This is weird since
1107                  * it's always been there, but don't freak out, just try and
1108                  * mount the top-level subvolume.
1109                  */
1110                 btrfs_free_path(path);
1111                 *objectid = BTRFS_FS_TREE_OBJECTID;
1112                 return 0;
1113         }
1114
1115         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1116         btrfs_free_path(path);
1117         *objectid = location.objectid;
1118         return 0;
1119 }
1120
1121 static int btrfs_fill_super(struct super_block *sb,
1122                             struct btrfs_fs_devices *fs_devices,
1123                             void *data)
1124 {
1125         struct inode *inode;
1126         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1127         int err;
1128
1129         sb->s_maxbytes = MAX_LFS_FILESIZE;
1130         sb->s_magic = BTRFS_SUPER_MAGIC;
1131         sb->s_op = &btrfs_super_ops;
1132         sb->s_d_op = &btrfs_dentry_operations;
1133         sb->s_export_op = &btrfs_export_ops;
1134 #ifdef CONFIG_FS_VERITY
1135         sb->s_vop = &btrfs_verityops;
1136 #endif
1137         sb->s_xattr = btrfs_xattr_handlers;
1138         sb->s_time_gran = 1;
1139 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1140         sb->s_flags |= SB_POSIXACL;
1141 #endif
1142         sb->s_flags |= SB_I_VERSION;
1143         sb->s_iflags |= SB_I_CGROUPWB;
1144
1145         err = super_setup_bdi(sb);
1146         if (err) {
1147                 btrfs_err(fs_info, "super_setup_bdi failed");
1148                 return err;
1149         }
1150
1151         err = open_ctree(sb, fs_devices, (char *)data);
1152         if (err) {
1153                 btrfs_err(fs_info, "open_ctree failed");
1154                 return err;
1155         }
1156
1157         inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1158         if (IS_ERR(inode)) {
1159                 err = PTR_ERR(inode);
1160                 goto fail_close;
1161         }
1162
1163         sb->s_root = d_make_root(inode);
1164         if (!sb->s_root) {
1165                 err = -ENOMEM;
1166                 goto fail_close;
1167         }
1168
1169         sb->s_flags |= SB_ACTIVE;
1170         return 0;
1171
1172 fail_close:
1173         close_ctree(fs_info);
1174         return err;
1175 }
1176
1177 int btrfs_sync_fs(struct super_block *sb, int wait)
1178 {
1179         struct btrfs_trans_handle *trans;
1180         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1181         struct btrfs_root *root = fs_info->tree_root;
1182
1183         trace_btrfs_sync_fs(fs_info, wait);
1184
1185         if (!wait) {
1186                 filemap_flush(fs_info->btree_inode->i_mapping);
1187                 return 0;
1188         }
1189
1190         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1191
1192         trans = btrfs_attach_transaction_barrier(root);
1193         if (IS_ERR(trans)) {
1194                 /* no transaction, don't bother */
1195                 if (PTR_ERR(trans) == -ENOENT) {
1196                         /*
1197                          * Exit unless we have some pending changes
1198                          * that need to go through commit
1199                          */
1200                         if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
1201                                       &fs_info->flags))
1202                                 return 0;
1203                         /*
1204                          * A non-blocking test if the fs is frozen. We must not
1205                          * start a new transaction here otherwise a deadlock
1206                          * happens. The pending operations are delayed to the
1207                          * next commit after thawing.
1208                          */
1209                         if (sb_start_write_trylock(sb))
1210                                 sb_end_write(sb);
1211                         else
1212                                 return 0;
1213                         trans = btrfs_start_transaction(root, 0);
1214                 }
1215                 if (IS_ERR(trans))
1216                         return PTR_ERR(trans);
1217         }
1218         return btrfs_commit_transaction(trans);
1219 }
1220
1221 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1222 {
1223         seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1224         *printed = true;
1225 }
1226
1227 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1228 {
1229         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1230         const char *compress_type;
1231         const char *subvol_name;
1232         bool printed = false;
1233
1234         if (btrfs_test_opt(info, DEGRADED))
1235                 seq_puts(seq, ",degraded");
1236         if (btrfs_test_opt(info, NODATASUM))
1237                 seq_puts(seq, ",nodatasum");
1238         if (btrfs_test_opt(info, NODATACOW))
1239                 seq_puts(seq, ",nodatacow");
1240         if (btrfs_test_opt(info, NOBARRIER))
1241                 seq_puts(seq, ",nobarrier");
1242         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1243                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1244         if (info->thread_pool_size !=  min_t(unsigned long,
1245                                              num_online_cpus() + 2, 8))
1246                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1247         if (btrfs_test_opt(info, COMPRESS)) {
1248                 compress_type = btrfs_compress_type2str(info->compress_type);
1249                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1250                         seq_printf(seq, ",compress-force=%s", compress_type);
1251                 else
1252                         seq_printf(seq, ",compress=%s", compress_type);
1253                 if (info->compress_level)
1254                         seq_printf(seq, ":%d", info->compress_level);
1255         }
1256         if (btrfs_test_opt(info, NOSSD))
1257                 seq_puts(seq, ",nossd");
1258         if (btrfs_test_opt(info, SSD_SPREAD))
1259                 seq_puts(seq, ",ssd_spread");
1260         else if (btrfs_test_opt(info, SSD))
1261                 seq_puts(seq, ",ssd");
1262         if (btrfs_test_opt(info, NOTREELOG))
1263                 seq_puts(seq, ",notreelog");
1264         if (btrfs_test_opt(info, NOLOGREPLAY))
1265                 print_rescue_option(seq, "nologreplay", &printed);
1266         if (btrfs_test_opt(info, USEBACKUPROOT))
1267                 print_rescue_option(seq, "usebackuproot", &printed);
1268         if (btrfs_test_opt(info, IGNOREBADROOTS))
1269                 print_rescue_option(seq, "ignorebadroots", &printed);
1270         if (btrfs_test_opt(info, IGNOREDATACSUMS))
1271                 print_rescue_option(seq, "ignoredatacsums", &printed);
1272         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1273                 seq_puts(seq, ",flushoncommit");
1274         if (btrfs_test_opt(info, DISCARD_SYNC))
1275                 seq_puts(seq, ",discard");
1276         if (btrfs_test_opt(info, DISCARD_ASYNC))
1277                 seq_puts(seq, ",discard=async");
1278         if (!(info->sb->s_flags & SB_POSIXACL))
1279                 seq_puts(seq, ",noacl");
1280         if (btrfs_free_space_cache_v1_active(info))
1281                 seq_puts(seq, ",space_cache");
1282         else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1283                 seq_puts(seq, ",space_cache=v2");
1284         else
1285                 seq_puts(seq, ",nospace_cache");
1286         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1287                 seq_puts(seq, ",rescan_uuid_tree");
1288         if (btrfs_test_opt(info, CLEAR_CACHE))
1289                 seq_puts(seq, ",clear_cache");
1290         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1291                 seq_puts(seq, ",user_subvol_rm_allowed");
1292         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1293                 seq_puts(seq, ",enospc_debug");
1294         if (btrfs_test_opt(info, AUTO_DEFRAG))
1295                 seq_puts(seq, ",autodefrag");
1296         if (btrfs_test_opt(info, SKIP_BALANCE))
1297                 seq_puts(seq, ",skip_balance");
1298 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1299         if (btrfs_test_opt(info, CHECK_INTEGRITY_DATA))
1300                 seq_puts(seq, ",check_int_data");
1301         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1302                 seq_puts(seq, ",check_int");
1303         if (info->check_integrity_print_mask)
1304                 seq_printf(seq, ",check_int_print_mask=%d",
1305                                 info->check_integrity_print_mask);
1306 #endif
1307         if (info->metadata_ratio)
1308                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1309         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1310                 seq_puts(seq, ",fatal_errors=panic");
1311         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1312                 seq_printf(seq, ",commit=%u", info->commit_interval);
1313 #ifdef CONFIG_BTRFS_DEBUG
1314         if (btrfs_test_opt(info, FRAGMENT_DATA))
1315                 seq_puts(seq, ",fragment=data");
1316         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1317                 seq_puts(seq, ",fragment=metadata");
1318 #endif
1319         if (btrfs_test_opt(info, REF_VERIFY))
1320                 seq_puts(seq, ",ref_verify");
1321         seq_printf(seq, ",subvolid=%llu",
1322                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1323         subvol_name = btrfs_get_subvol_name_from_objectid(info,
1324                         BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1325         if (!IS_ERR(subvol_name)) {
1326                 seq_puts(seq, ",subvol=");
1327                 seq_escape(seq, subvol_name, " \t\n\\");
1328                 kfree(subvol_name);
1329         }
1330         return 0;
1331 }
1332
1333 static int btrfs_test_super(struct super_block *s, void *data)
1334 {
1335         struct btrfs_fs_info *p = data;
1336         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1337
1338         return fs_info->fs_devices == p->fs_devices;
1339 }
1340
1341 static int btrfs_set_super(struct super_block *s, void *data)
1342 {
1343         int err = set_anon_super(s, data);
1344         if (!err)
1345                 s->s_fs_info = data;
1346         return err;
1347 }
1348
1349 /*
1350  * subvolumes are identified by ino 256
1351  */
1352 static inline int is_subvolume_inode(struct inode *inode)
1353 {
1354         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1355                 return 1;
1356         return 0;
1357 }
1358
1359 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1360                                    struct vfsmount *mnt)
1361 {
1362         struct dentry *root;
1363         int ret;
1364
1365         if (!subvol_name) {
1366                 if (!subvol_objectid) {
1367                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1368                                                           &subvol_objectid);
1369                         if (ret) {
1370                                 root = ERR_PTR(ret);
1371                                 goto out;
1372                         }
1373                 }
1374                 subvol_name = btrfs_get_subvol_name_from_objectid(
1375                                         btrfs_sb(mnt->mnt_sb), subvol_objectid);
1376                 if (IS_ERR(subvol_name)) {
1377                         root = ERR_CAST(subvol_name);
1378                         subvol_name = NULL;
1379                         goto out;
1380                 }
1381
1382         }
1383
1384         root = mount_subtree(mnt, subvol_name);
1385         /* mount_subtree() drops our reference on the vfsmount. */
1386         mnt = NULL;
1387
1388         if (!IS_ERR(root)) {
1389                 struct super_block *s = root->d_sb;
1390                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1391                 struct inode *root_inode = d_inode(root);
1392                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1393
1394                 ret = 0;
1395                 if (!is_subvolume_inode(root_inode)) {
1396                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1397                                subvol_name);
1398                         ret = -EINVAL;
1399                 }
1400                 if (subvol_objectid && root_objectid != subvol_objectid) {
1401                         /*
1402                          * This will also catch a race condition where a
1403                          * subvolume which was passed by ID is renamed and
1404                          * another subvolume is renamed over the old location.
1405                          */
1406                         btrfs_err(fs_info,
1407                                   "subvol '%s' does not match subvolid %llu",
1408                                   subvol_name, subvol_objectid);
1409                         ret = -EINVAL;
1410                 }
1411                 if (ret) {
1412                         dput(root);
1413                         root = ERR_PTR(ret);
1414                         deactivate_locked_super(s);
1415                 }
1416         }
1417
1418 out:
1419         mntput(mnt);
1420         kfree(subvol_name);
1421         return root;
1422 }
1423
1424 /*
1425  * Find a superblock for the given device / mount point.
1426  *
1427  * Note: This is based on mount_bdev from fs/super.c with a few additions
1428  *       for multiple device setup.  Make sure to keep it in sync.
1429  */
1430 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1431                 int flags, const char *device_name, void *data)
1432 {
1433         struct block_device *bdev = NULL;
1434         struct super_block *s;
1435         struct btrfs_device *device = NULL;
1436         struct btrfs_fs_devices *fs_devices = NULL;
1437         struct btrfs_fs_info *fs_info = NULL;
1438         void *new_sec_opts = NULL;
1439         fmode_t mode = FMODE_READ;
1440         int error = 0;
1441
1442         if (!(flags & SB_RDONLY))
1443                 mode |= FMODE_WRITE;
1444
1445         if (data) {
1446                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1447                 if (error)
1448                         return ERR_PTR(error);
1449         }
1450
1451         /*
1452          * Setup a dummy root and fs_info for test/set super.  This is because
1453          * we don't actually fill this stuff out until open_ctree, but we need
1454          * then open_ctree will properly initialize the file system specific
1455          * settings later.  btrfs_init_fs_info initializes the static elements
1456          * of the fs_info (locks and such) to make cleanup easier if we find a
1457          * superblock with our given fs_devices later on at sget() time.
1458          */
1459         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1460         if (!fs_info) {
1461                 error = -ENOMEM;
1462                 goto error_sec_opts;
1463         }
1464         btrfs_init_fs_info(fs_info);
1465
1466         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1467         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1468         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1469                 error = -ENOMEM;
1470                 goto error_fs_info;
1471         }
1472
1473         mutex_lock(&uuid_mutex);
1474         error = btrfs_parse_device_options(data, mode, fs_type);
1475         if (error) {
1476                 mutex_unlock(&uuid_mutex);
1477                 goto error_fs_info;
1478         }
1479
1480         device = btrfs_scan_one_device(device_name, mode, fs_type);
1481         if (IS_ERR(device)) {
1482                 mutex_unlock(&uuid_mutex);
1483                 error = PTR_ERR(device);
1484                 goto error_fs_info;
1485         }
1486
1487         fs_devices = device->fs_devices;
1488         fs_info->fs_devices = fs_devices;
1489
1490         error = btrfs_open_devices(fs_devices, mode, fs_type);
1491         mutex_unlock(&uuid_mutex);
1492         if (error)
1493                 goto error_fs_info;
1494
1495         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1496                 error = -EACCES;
1497                 goto error_close_devices;
1498         }
1499
1500         bdev = fs_devices->latest_dev->bdev;
1501         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1502                  fs_info);
1503         if (IS_ERR(s)) {
1504                 error = PTR_ERR(s);
1505                 goto error_close_devices;
1506         }
1507
1508         if (s->s_root) {
1509                 btrfs_close_devices(fs_devices);
1510                 btrfs_free_fs_info(fs_info);
1511                 if ((flags ^ s->s_flags) & SB_RDONLY)
1512                         error = -EBUSY;
1513         } else {
1514                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1515                 shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name,
1516                                         s->s_id);
1517                 btrfs_sb(s)->bdev_holder = fs_type;
1518                 if (!strstr(crc32c_impl(), "generic"))
1519                         set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
1520                 error = btrfs_fill_super(s, fs_devices, data);
1521         }
1522         if (!error)
1523                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1524         security_free_mnt_opts(&new_sec_opts);
1525         if (error) {
1526                 deactivate_locked_super(s);
1527                 return ERR_PTR(error);
1528         }
1529
1530         return dget(s->s_root);
1531
1532 error_close_devices:
1533         btrfs_close_devices(fs_devices);
1534 error_fs_info:
1535         btrfs_free_fs_info(fs_info);
1536 error_sec_opts:
1537         security_free_mnt_opts(&new_sec_opts);
1538         return ERR_PTR(error);
1539 }
1540
1541 /*
1542  * Mount function which is called by VFS layer.
1543  *
1544  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1545  * which needs vfsmount* of device's root (/).  This means device's root has to
1546  * be mounted internally in any case.
1547  *
1548  * Operation flow:
1549  *   1. Parse subvol id related options for later use in mount_subvol().
1550  *
1551  *   2. Mount device's root (/) by calling vfs_kern_mount().
1552  *
1553  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1554  *      first place. In order to avoid calling btrfs_mount() again, we use
1555  *      different file_system_type which is not registered to VFS by
1556  *      register_filesystem() (btrfs_root_fs_type). As a result,
1557  *      btrfs_mount_root() is called. The return value will be used by
1558  *      mount_subtree() in mount_subvol().
1559  *
1560  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1561  *      "btrfs subvolume set-default", mount_subvol() is called always.
1562  */
1563 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1564                 const char *device_name, void *data)
1565 {
1566         struct vfsmount *mnt_root;
1567         struct dentry *root;
1568         char *subvol_name = NULL;
1569         u64 subvol_objectid = 0;
1570         int error = 0;
1571
1572         error = btrfs_parse_subvol_options(data, &subvol_name,
1573                                         &subvol_objectid);
1574         if (error) {
1575                 kfree(subvol_name);
1576                 return ERR_PTR(error);
1577         }
1578
1579         /* mount device's root (/) */
1580         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1581         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1582                 if (flags & SB_RDONLY) {
1583                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1584                                 flags & ~SB_RDONLY, device_name, data);
1585                 } else {
1586                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1587                                 flags | SB_RDONLY, device_name, data);
1588                         if (IS_ERR(mnt_root)) {
1589                                 root = ERR_CAST(mnt_root);
1590                                 kfree(subvol_name);
1591                                 goto out;
1592                         }
1593
1594                         down_write(&mnt_root->mnt_sb->s_umount);
1595                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1596                         up_write(&mnt_root->mnt_sb->s_umount);
1597                         if (error < 0) {
1598                                 root = ERR_PTR(error);
1599                                 mntput(mnt_root);
1600                                 kfree(subvol_name);
1601                                 goto out;
1602                         }
1603                 }
1604         }
1605         if (IS_ERR(mnt_root)) {
1606                 root = ERR_CAST(mnt_root);
1607                 kfree(subvol_name);
1608                 goto out;
1609         }
1610
1611         /* mount_subvol() will free subvol_name and mnt_root */
1612         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1613
1614 out:
1615         return root;
1616 }
1617
1618 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1619                                      u32 new_pool_size, u32 old_pool_size)
1620 {
1621         if (new_pool_size == old_pool_size)
1622                 return;
1623
1624         fs_info->thread_pool_size = new_pool_size;
1625
1626         btrfs_info(fs_info, "resize thread pool %d -> %d",
1627                old_pool_size, new_pool_size);
1628
1629         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1630         btrfs_workqueue_set_max(fs_info->hipri_workers, new_pool_size);
1631         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1632         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1633         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1634         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1635         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1636 }
1637
1638 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1639                                        unsigned long old_opts, int flags)
1640 {
1641         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1642             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1643              (flags & SB_RDONLY))) {
1644                 /* wait for any defraggers to finish */
1645                 wait_event(fs_info->transaction_wait,
1646                            (atomic_read(&fs_info->defrag_running) == 0));
1647                 if (flags & SB_RDONLY)
1648                         sync_filesystem(fs_info->sb);
1649         }
1650 }
1651
1652 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1653                                          unsigned long old_opts)
1654 {
1655         const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1656
1657         /*
1658          * We need to cleanup all defragable inodes if the autodefragment is
1659          * close or the filesystem is read only.
1660          */
1661         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1662             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1663                 btrfs_cleanup_defrag_inodes(fs_info);
1664         }
1665
1666         /* If we toggled discard async */
1667         if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1668             btrfs_test_opt(fs_info, DISCARD_ASYNC))
1669                 btrfs_discard_resume(fs_info);
1670         else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1671                  !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1672                 btrfs_discard_cleanup(fs_info);
1673
1674         /* If we toggled space cache */
1675         if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1676                 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1677 }
1678
1679 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1680 {
1681         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1682         unsigned old_flags = sb->s_flags;
1683         unsigned long old_opts = fs_info->mount_opt;
1684         unsigned long old_compress_type = fs_info->compress_type;
1685         u64 old_max_inline = fs_info->max_inline;
1686         u32 old_thread_pool_size = fs_info->thread_pool_size;
1687         u32 old_metadata_ratio = fs_info->metadata_ratio;
1688         int ret;
1689
1690         sync_filesystem(sb);
1691         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1692
1693         if (data) {
1694                 void *new_sec_opts = NULL;
1695
1696                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1697                 if (!ret)
1698                         ret = security_sb_remount(sb, new_sec_opts);
1699                 security_free_mnt_opts(&new_sec_opts);
1700                 if (ret)
1701                         goto restore;
1702         }
1703
1704         ret = btrfs_parse_options(fs_info, data, *flags);
1705         if (ret)
1706                 goto restore;
1707
1708         ret = btrfs_check_features(fs_info, sb);
1709         if (ret < 0)
1710                 goto restore;
1711
1712         btrfs_remount_begin(fs_info, old_opts, *flags);
1713         btrfs_resize_thread_pool(fs_info,
1714                 fs_info->thread_pool_size, old_thread_pool_size);
1715
1716         if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1717             (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1718             (!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
1719                 btrfs_warn(fs_info,
1720                 "remount supports changing free space tree only from ro to rw");
1721                 /* Make sure free space cache options match the state on disk */
1722                 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1723                         btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1724                         btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1725                 }
1726                 if (btrfs_free_space_cache_v1_active(fs_info)) {
1727                         btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1728                         btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1729                 }
1730         }
1731
1732         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1733                 goto out;
1734
1735         if (*flags & SB_RDONLY) {
1736                 /*
1737                  * this also happens on 'umount -rf' or on shutdown, when
1738                  * the filesystem is busy.
1739                  */
1740                 cancel_work_sync(&fs_info->async_reclaim_work);
1741                 cancel_work_sync(&fs_info->async_data_reclaim_work);
1742
1743                 btrfs_discard_cleanup(fs_info);
1744
1745                 /* wait for the uuid_scan task to finish */
1746                 down(&fs_info->uuid_tree_rescan_sem);
1747                 /* avoid complains from lockdep et al. */
1748                 up(&fs_info->uuid_tree_rescan_sem);
1749
1750                 btrfs_set_sb_rdonly(sb);
1751
1752                 /*
1753                  * Setting SB_RDONLY will put the cleaner thread to
1754                  * sleep at the next loop if it's already active.
1755                  * If it's already asleep, we'll leave unused block
1756                  * groups on disk until we're mounted read-write again
1757                  * unless we clean them up here.
1758                  */
1759                 btrfs_delete_unused_bgs(fs_info);
1760
1761                 /*
1762                  * The cleaner task could be already running before we set the
1763                  * flag BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock).
1764                  * We must make sure that after we finish the remount, i.e. after
1765                  * we call btrfs_commit_super(), the cleaner can no longer start
1766                  * a transaction - either because it was dropping a dead root,
1767                  * running delayed iputs or deleting an unused block group (the
1768                  * cleaner picked a block group from the list of unused block
1769                  * groups before we were able to in the previous call to
1770                  * btrfs_delete_unused_bgs()).
1771                  */
1772                 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING,
1773                             TASK_UNINTERRUPTIBLE);
1774
1775                 /*
1776                  * We've set the superblock to RO mode, so we might have made
1777                  * the cleaner task sleep without running all pending delayed
1778                  * iputs. Go through all the delayed iputs here, so that if an
1779                  * unmount happens without remounting RW we don't end up at
1780                  * finishing close_ctree() with a non-empty list of delayed
1781                  * iputs.
1782                  */
1783                 btrfs_run_delayed_iputs(fs_info);
1784
1785                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1786                 btrfs_scrub_cancel(fs_info);
1787                 btrfs_pause_balance(fs_info);
1788
1789                 /*
1790                  * Pause the qgroup rescan worker if it is running. We don't want
1791                  * it to be still running after we are in RO mode, as after that,
1792                  * by the time we unmount, it might have left a transaction open,
1793                  * so we would leak the transaction and/or crash.
1794                  */
1795                 btrfs_qgroup_wait_for_completion(fs_info, false);
1796
1797                 ret = btrfs_commit_super(fs_info);
1798                 if (ret)
1799                         goto restore;
1800         } else {
1801                 if (BTRFS_FS_ERROR(fs_info)) {
1802                         btrfs_err(fs_info,
1803                                 "Remounting read-write after error is not allowed");
1804                         ret = -EINVAL;
1805                         goto restore;
1806                 }
1807                 if (fs_info->fs_devices->rw_devices == 0) {
1808                         ret = -EACCES;
1809                         goto restore;
1810                 }
1811
1812                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1813                         btrfs_warn(fs_info,
1814                 "too many missing devices, writable remount is not allowed");
1815                         ret = -EACCES;
1816                         goto restore;
1817                 }
1818
1819                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1820                         btrfs_warn(fs_info,
1821                 "mount required to replay tree-log, cannot remount read-write");
1822                         ret = -EINVAL;
1823                         goto restore;
1824                 }
1825
1826                 /*
1827                  * NOTE: when remounting with a change that does writes, don't
1828                  * put it anywhere above this point, as we are not sure to be
1829                  * safe to write until we pass the above checks.
1830                  */
1831                 ret = btrfs_start_pre_rw_mount(fs_info);
1832                 if (ret)
1833                         goto restore;
1834
1835                 btrfs_clear_sb_rdonly(sb);
1836
1837                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1838         }
1839 out:
1840         /*
1841          * We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
1842          * since the absence of the flag means it can be toggled off by remount.
1843          */
1844         *flags |= SB_I_VERSION;
1845
1846         wake_up_process(fs_info->transaction_kthread);
1847         btrfs_remount_cleanup(fs_info, old_opts);
1848         btrfs_clear_oneshot_options(fs_info);
1849         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1850
1851         return 0;
1852
1853 restore:
1854         /* We've hit an error - don't reset SB_RDONLY */
1855         if (sb_rdonly(sb))
1856                 old_flags |= SB_RDONLY;
1857         if (!(old_flags & SB_RDONLY))
1858                 clear_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
1859         sb->s_flags = old_flags;
1860         fs_info->mount_opt = old_opts;
1861         fs_info->compress_type = old_compress_type;
1862         fs_info->max_inline = old_max_inline;
1863         btrfs_resize_thread_pool(fs_info,
1864                 old_thread_pool_size, fs_info->thread_pool_size);
1865         fs_info->metadata_ratio = old_metadata_ratio;
1866         btrfs_remount_cleanup(fs_info, old_opts);
1867         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1868
1869         return ret;
1870 }
1871
1872 /* Used to sort the devices by max_avail(descending sort) */
1873 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1874 {
1875         const struct btrfs_device_info *dev_info1 = a;
1876         const struct btrfs_device_info *dev_info2 = b;
1877
1878         if (dev_info1->max_avail > dev_info2->max_avail)
1879                 return -1;
1880         else if (dev_info1->max_avail < dev_info2->max_avail)
1881                 return 1;
1882         return 0;
1883 }
1884
1885 /*
1886  * sort the devices by max_avail, in which max free extent size of each device
1887  * is stored.(Descending Sort)
1888  */
1889 static inline void btrfs_descending_sort_devices(
1890                                         struct btrfs_device_info *devices,
1891                                         size_t nr_devices)
1892 {
1893         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1894              btrfs_cmp_device_free_bytes, NULL);
1895 }
1896
1897 /*
1898  * The helper to calc the free space on the devices that can be used to store
1899  * file data.
1900  */
1901 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1902                                               u64 *free_bytes)
1903 {
1904         struct btrfs_device_info *devices_info;
1905         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1906         struct btrfs_device *device;
1907         u64 type;
1908         u64 avail_space;
1909         u64 min_stripe_size;
1910         int num_stripes = 1;
1911         int i = 0, nr_devices;
1912         const struct btrfs_raid_attr *rattr;
1913
1914         /*
1915          * We aren't under the device list lock, so this is racy-ish, but good
1916          * enough for our purposes.
1917          */
1918         nr_devices = fs_info->fs_devices->open_devices;
1919         if (!nr_devices) {
1920                 smp_mb();
1921                 nr_devices = fs_info->fs_devices->open_devices;
1922                 ASSERT(nr_devices);
1923                 if (!nr_devices) {
1924                         *free_bytes = 0;
1925                         return 0;
1926                 }
1927         }
1928
1929         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1930                                GFP_KERNEL);
1931         if (!devices_info)
1932                 return -ENOMEM;
1933
1934         /* calc min stripe number for data space allocation */
1935         type = btrfs_data_alloc_profile(fs_info);
1936         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1937
1938         if (type & BTRFS_BLOCK_GROUP_RAID0)
1939                 num_stripes = nr_devices;
1940         else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1941                 num_stripes = rattr->ncopies;
1942         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1943                 num_stripes = 4;
1944
1945         /* Adjust for more than 1 stripe per device */
1946         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1947
1948         rcu_read_lock();
1949         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1950                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1951                                                 &device->dev_state) ||
1952                     !device->bdev ||
1953                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1954                         continue;
1955
1956                 if (i >= nr_devices)
1957                         break;
1958
1959                 avail_space = device->total_bytes - device->bytes_used;
1960
1961                 /* align with stripe_len */
1962                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1963
1964                 /*
1965                  * Ensure we have at least min_stripe_size on top of the
1966                  * reserved space on the device.
1967                  */
1968                 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1969                         continue;
1970
1971                 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1972
1973                 devices_info[i].dev = device;
1974                 devices_info[i].max_avail = avail_space;
1975
1976                 i++;
1977         }
1978         rcu_read_unlock();
1979
1980         nr_devices = i;
1981
1982         btrfs_descending_sort_devices(devices_info, nr_devices);
1983
1984         i = nr_devices - 1;
1985         avail_space = 0;
1986         while (nr_devices >= rattr->devs_min) {
1987                 num_stripes = min(num_stripes, nr_devices);
1988
1989                 if (devices_info[i].max_avail >= min_stripe_size) {
1990                         int j;
1991                         u64 alloc_size;
1992
1993                         avail_space += devices_info[i].max_avail * num_stripes;
1994                         alloc_size = devices_info[i].max_avail;
1995                         for (j = i + 1 - num_stripes; j <= i; j++)
1996                                 devices_info[j].max_avail -= alloc_size;
1997                 }
1998                 i--;
1999                 nr_devices--;
2000         }
2001
2002         kfree(devices_info);
2003         *free_bytes = avail_space;
2004         return 0;
2005 }
2006
2007 /*
2008  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2009  *
2010  * If there's a redundant raid level at DATA block groups, use the respective
2011  * multiplier to scale the sizes.
2012  *
2013  * Unused device space usage is based on simulating the chunk allocator
2014  * algorithm that respects the device sizes and order of allocations.  This is
2015  * a close approximation of the actual use but there are other factors that may
2016  * change the result (like a new metadata chunk).
2017  *
2018  * If metadata is exhausted, f_bavail will be 0.
2019  */
2020 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2021 {
2022         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2023         struct btrfs_super_block *disk_super = fs_info->super_copy;
2024         struct btrfs_space_info *found;
2025         u64 total_used = 0;
2026         u64 total_free_data = 0;
2027         u64 total_free_meta = 0;
2028         u32 bits = fs_info->sectorsize_bits;
2029         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2030         unsigned factor = 1;
2031         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2032         int ret;
2033         u64 thresh = 0;
2034         int mixed = 0;
2035
2036         list_for_each_entry(found, &fs_info->space_info, list) {
2037                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2038                         int i;
2039
2040                         total_free_data += found->disk_total - found->disk_used;
2041                         total_free_data -=
2042                                 btrfs_account_ro_block_groups_free_space(found);
2043
2044                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2045                                 if (!list_empty(&found->block_groups[i]))
2046                                         factor = btrfs_bg_type_to_factor(
2047                                                 btrfs_raid_array[i].bg_flag);
2048                         }
2049                 }
2050
2051                 /*
2052                  * Metadata in mixed block goup profiles are accounted in data
2053                  */
2054                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2055                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2056                                 mixed = 1;
2057                         else
2058                                 total_free_meta += found->disk_total -
2059                                         found->disk_used;
2060                 }
2061
2062                 total_used += found->disk_used;
2063         }
2064
2065         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2066         buf->f_blocks >>= bits;
2067         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2068
2069         /* Account global block reserve as used, it's in logical size already */
2070         spin_lock(&block_rsv->lock);
2071         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2072         if (buf->f_bfree >= block_rsv->size >> bits)
2073                 buf->f_bfree -= block_rsv->size >> bits;
2074         else
2075                 buf->f_bfree = 0;
2076         spin_unlock(&block_rsv->lock);
2077
2078         buf->f_bavail = div_u64(total_free_data, factor);
2079         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2080         if (ret)
2081                 return ret;
2082         buf->f_bavail += div_u64(total_free_data, factor);
2083         buf->f_bavail = buf->f_bavail >> bits;
2084
2085         /*
2086          * We calculate the remaining metadata space minus global reserve. If
2087          * this is (supposedly) smaller than zero, there's no space. But this
2088          * does not hold in practice, the exhausted state happens where's still
2089          * some positive delta. So we apply some guesswork and compare the
2090          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2091          *
2092          * We probably cannot calculate the exact threshold value because this
2093          * depends on the internal reservations requested by various
2094          * operations, so some operations that consume a few metadata will
2095          * succeed even if the Avail is zero. But this is better than the other
2096          * way around.
2097          */
2098         thresh = SZ_4M;
2099
2100         /*
2101          * We only want to claim there's no available space if we can no longer
2102          * allocate chunks for our metadata profile and our global reserve will
2103          * not fit in the free metadata space.  If we aren't ->full then we
2104          * still can allocate chunks and thus are fine using the currently
2105          * calculated f_bavail.
2106          */
2107         if (!mixed && block_rsv->space_info->full &&
2108             total_free_meta - thresh < block_rsv->size)
2109                 buf->f_bavail = 0;
2110
2111         buf->f_type = BTRFS_SUPER_MAGIC;
2112         buf->f_bsize = dentry->d_sb->s_blocksize;
2113         buf->f_namelen = BTRFS_NAME_LEN;
2114
2115         /* We treat it as constant endianness (it doesn't matter _which_)
2116            because we want the fsid to come out the same whether mounted
2117            on a big-endian or little-endian host */
2118         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2119         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2120         /* Mask in the root object ID too, to disambiguate subvols */
2121         buf->f_fsid.val[0] ^=
2122                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2123         buf->f_fsid.val[1] ^=
2124                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2125
2126         return 0;
2127 }
2128
2129 static void btrfs_kill_super(struct super_block *sb)
2130 {
2131         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2132         kill_anon_super(sb);
2133         btrfs_free_fs_info(fs_info);
2134 }
2135
2136 static struct file_system_type btrfs_fs_type = {
2137         .owner          = THIS_MODULE,
2138         .name           = "btrfs",
2139         .mount          = btrfs_mount,
2140         .kill_sb        = btrfs_kill_super,
2141         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2142 };
2143
2144 static struct file_system_type btrfs_root_fs_type = {
2145         .owner          = THIS_MODULE,
2146         .name           = "btrfs",
2147         .mount          = btrfs_mount_root,
2148         .kill_sb        = btrfs_kill_super,
2149         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2150 };
2151
2152 MODULE_ALIAS_FS("btrfs");
2153
2154 static int btrfs_control_open(struct inode *inode, struct file *file)
2155 {
2156         /*
2157          * The control file's private_data is used to hold the
2158          * transaction when it is started and is used to keep
2159          * track of whether a transaction is already in progress.
2160          */
2161         file->private_data = NULL;
2162         return 0;
2163 }
2164
2165 /*
2166  * Used by /dev/btrfs-control for devices ioctls.
2167  */
2168 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2169                                 unsigned long arg)
2170 {
2171         struct btrfs_ioctl_vol_args *vol;
2172         struct btrfs_device *device = NULL;
2173         dev_t devt = 0;
2174         int ret = -ENOTTY;
2175
2176         if (!capable(CAP_SYS_ADMIN))
2177                 return -EPERM;
2178
2179         vol = memdup_user((void __user *)arg, sizeof(*vol));
2180         if (IS_ERR(vol))
2181                 return PTR_ERR(vol);
2182         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2183
2184         switch (cmd) {
2185         case BTRFS_IOC_SCAN_DEV:
2186                 mutex_lock(&uuid_mutex);
2187                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2188                                                &btrfs_root_fs_type);
2189                 ret = PTR_ERR_OR_ZERO(device);
2190                 mutex_unlock(&uuid_mutex);
2191                 break;
2192         case BTRFS_IOC_FORGET_DEV:
2193                 if (vol->name[0] != 0) {
2194                         ret = lookup_bdev(vol->name, &devt);
2195                         if (ret)
2196                                 break;
2197                 }
2198                 ret = btrfs_forget_devices(devt);
2199                 break;
2200         case BTRFS_IOC_DEVICES_READY:
2201                 mutex_lock(&uuid_mutex);
2202                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2203                                                &btrfs_root_fs_type);
2204                 if (IS_ERR(device)) {
2205                         mutex_unlock(&uuid_mutex);
2206                         ret = PTR_ERR(device);
2207                         break;
2208                 }
2209                 ret = !(device->fs_devices->num_devices ==
2210                         device->fs_devices->total_devices);
2211                 mutex_unlock(&uuid_mutex);
2212                 break;
2213         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2214                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2215                 break;
2216         }
2217
2218         kfree(vol);
2219         return ret;
2220 }
2221
2222 static int btrfs_freeze(struct super_block *sb)
2223 {
2224         struct btrfs_trans_handle *trans;
2225         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2226         struct btrfs_root *root = fs_info->tree_root;
2227
2228         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2229         /*
2230          * We don't need a barrier here, we'll wait for any transaction that
2231          * could be in progress on other threads (and do delayed iputs that
2232          * we want to avoid on a frozen filesystem), or do the commit
2233          * ourselves.
2234          */
2235         trans = btrfs_attach_transaction_barrier(root);
2236         if (IS_ERR(trans)) {
2237                 /* no transaction, don't bother */
2238                 if (PTR_ERR(trans) == -ENOENT)
2239                         return 0;
2240                 return PTR_ERR(trans);
2241         }
2242         return btrfs_commit_transaction(trans);
2243 }
2244
2245 static int check_dev_super(struct btrfs_device *dev)
2246 {
2247         struct btrfs_fs_info *fs_info = dev->fs_info;
2248         struct btrfs_super_block *sb;
2249         u16 csum_type;
2250         int ret = 0;
2251
2252         /* This should be called with fs still frozen. */
2253         ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2254
2255         /* Missing dev, no need to check. */
2256         if (!dev->bdev)
2257                 return 0;
2258
2259         /* Only need to check the primary super block. */
2260         sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2261         if (IS_ERR(sb))
2262                 return PTR_ERR(sb);
2263
2264         /* Verify the checksum. */
2265         csum_type = btrfs_super_csum_type(sb);
2266         if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2267                 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2268                           csum_type, btrfs_super_csum_type(fs_info->super_copy));
2269                 ret = -EUCLEAN;
2270                 goto out;
2271         }
2272
2273         if (btrfs_check_super_csum(fs_info, sb)) {
2274                 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2275                 ret = -EUCLEAN;
2276                 goto out;
2277         }
2278
2279         /* Btrfs_validate_super() includes fsid check against super->fsid. */
2280         ret = btrfs_validate_super(fs_info, sb, 0);
2281         if (ret < 0)
2282                 goto out;
2283
2284         if (btrfs_super_generation(sb) != fs_info->last_trans_committed) {
2285                 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2286                         btrfs_super_generation(sb),
2287                         fs_info->last_trans_committed);
2288                 ret = -EUCLEAN;
2289                 goto out;
2290         }
2291 out:
2292         btrfs_release_disk_super(sb);
2293         return ret;
2294 }
2295
2296 static int btrfs_unfreeze(struct super_block *sb)
2297 {
2298         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2299         struct btrfs_device *device;
2300         int ret = 0;
2301
2302         /*
2303          * Make sure the fs is not changed by accident (like hibernation then
2304          * modified by other OS).
2305          * If we found anything wrong, we mark the fs error immediately.
2306          *
2307          * And since the fs is frozen, no one can modify the fs yet, thus
2308          * we don't need to hold device_list_mutex.
2309          */
2310         list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2311                 ret = check_dev_super(device);
2312                 if (ret < 0) {
2313                         btrfs_handle_fs_error(fs_info, ret,
2314                                 "super block on devid %llu got modified unexpectedly",
2315                                 device->devid);
2316                         break;
2317                 }
2318         }
2319         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2320
2321         /*
2322          * We still return 0, to allow VFS layer to unfreeze the fs even the
2323          * above checks failed. Since the fs is either fine or read-only, we're
2324          * safe to continue, without causing further damage.
2325          */
2326         return 0;
2327 }
2328
2329 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2330 {
2331         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2332
2333         /*
2334          * There should be always a valid pointer in latest_dev, it may be stale
2335          * for a short moment in case it's being deleted but still valid until
2336          * the end of RCU grace period.
2337          */
2338         rcu_read_lock();
2339         seq_escape(m, rcu_str_deref(fs_info->fs_devices->latest_dev->name), " \t\n\\");
2340         rcu_read_unlock();
2341
2342         return 0;
2343 }
2344
2345 static const struct super_operations btrfs_super_ops = {
2346         .drop_inode     = btrfs_drop_inode,
2347         .evict_inode    = btrfs_evict_inode,
2348         .put_super      = btrfs_put_super,
2349         .sync_fs        = btrfs_sync_fs,
2350         .show_options   = btrfs_show_options,
2351         .show_devname   = btrfs_show_devname,
2352         .alloc_inode    = btrfs_alloc_inode,
2353         .destroy_inode  = btrfs_destroy_inode,
2354         .free_inode     = btrfs_free_inode,
2355         .statfs         = btrfs_statfs,
2356         .remount_fs     = btrfs_remount,
2357         .freeze_fs      = btrfs_freeze,
2358         .unfreeze_fs    = btrfs_unfreeze,
2359 };
2360
2361 static const struct file_operations btrfs_ctl_fops = {
2362         .open = btrfs_control_open,
2363         .unlocked_ioctl  = btrfs_control_ioctl,
2364         .compat_ioctl = compat_ptr_ioctl,
2365         .owner   = THIS_MODULE,
2366         .llseek = noop_llseek,
2367 };
2368
2369 static struct miscdevice btrfs_misc = {
2370         .minor          = BTRFS_MINOR,
2371         .name           = "btrfs-control",
2372         .fops           = &btrfs_ctl_fops
2373 };
2374
2375 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2376 MODULE_ALIAS("devname:btrfs-control");
2377
2378 static int __init btrfs_interface_init(void)
2379 {
2380         return misc_register(&btrfs_misc);
2381 }
2382
2383 static __cold void btrfs_interface_exit(void)
2384 {
2385         misc_deregister(&btrfs_misc);
2386 }
2387
2388 static int __init btrfs_print_mod_info(void)
2389 {
2390         static const char options[] = ""
2391 #ifdef CONFIG_BTRFS_DEBUG
2392                         ", debug=on"
2393 #endif
2394 #ifdef CONFIG_BTRFS_ASSERT
2395                         ", assert=on"
2396 #endif
2397 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2398                         ", integrity-checker=on"
2399 #endif
2400 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2401                         ", ref-verify=on"
2402 #endif
2403 #ifdef CONFIG_BLK_DEV_ZONED
2404                         ", zoned=yes"
2405 #else
2406                         ", zoned=no"
2407 #endif
2408 #ifdef CONFIG_FS_VERITY
2409                         ", fsverity=yes"
2410 #else
2411                         ", fsverity=no"
2412 #endif
2413                         ;
2414         pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
2415         return 0;
2416 }
2417
2418 static int register_btrfs(void)
2419 {
2420         return register_filesystem(&btrfs_fs_type);
2421 }
2422
2423 static void unregister_btrfs(void)
2424 {
2425         unregister_filesystem(&btrfs_fs_type);
2426 }
2427
2428 /* Helper structure for long init/exit functions. */
2429 struct init_sequence {
2430         int (*init_func)(void);
2431         /* Can be NULL if the init_func doesn't need cleanup. */
2432         void (*exit_func)(void);
2433 };
2434
2435 static const struct init_sequence mod_init_seq[] = {
2436         {
2437                 .init_func = btrfs_props_init,
2438                 .exit_func = NULL,
2439         }, {
2440                 .init_func = btrfs_init_sysfs,
2441                 .exit_func = btrfs_exit_sysfs,
2442         }, {
2443                 .init_func = btrfs_init_compress,
2444                 .exit_func = btrfs_exit_compress,
2445         }, {
2446                 .init_func = btrfs_init_cachep,
2447                 .exit_func = btrfs_destroy_cachep,
2448         }, {
2449                 .init_func = btrfs_transaction_init,
2450                 .exit_func = btrfs_transaction_exit,
2451         }, {
2452                 .init_func = btrfs_ctree_init,
2453                 .exit_func = btrfs_ctree_exit,
2454         }, {
2455                 .init_func = btrfs_free_space_init,
2456                 .exit_func = btrfs_free_space_exit,
2457         }, {
2458                 .init_func = extent_state_init_cachep,
2459                 .exit_func = extent_state_free_cachep,
2460         }, {
2461                 .init_func = extent_buffer_init_cachep,
2462                 .exit_func = extent_buffer_free_cachep,
2463         }, {
2464                 .init_func = btrfs_bioset_init,
2465                 .exit_func = btrfs_bioset_exit,
2466         }, {
2467                 .init_func = extent_map_init,
2468                 .exit_func = extent_map_exit,
2469         }, {
2470                 .init_func = ordered_data_init,
2471                 .exit_func = ordered_data_exit,
2472         }, {
2473                 .init_func = btrfs_delayed_inode_init,
2474                 .exit_func = btrfs_delayed_inode_exit,
2475         }, {
2476                 .init_func = btrfs_auto_defrag_init,
2477                 .exit_func = btrfs_auto_defrag_exit,
2478         }, {
2479                 .init_func = btrfs_delayed_ref_init,
2480                 .exit_func = btrfs_delayed_ref_exit,
2481         }, {
2482                 .init_func = btrfs_prelim_ref_init,
2483                 .exit_func = btrfs_prelim_ref_exit,
2484         }, {
2485                 .init_func = btrfs_interface_init,
2486                 .exit_func = btrfs_interface_exit,
2487         }, {
2488                 .init_func = btrfs_print_mod_info,
2489                 .exit_func = NULL,
2490         }, {
2491                 .init_func = btrfs_run_sanity_tests,
2492                 .exit_func = NULL,
2493         }, {
2494                 .init_func = register_btrfs,
2495                 .exit_func = unregister_btrfs,
2496         }
2497 };
2498
2499 static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2500
2501 static __always_inline void btrfs_exit_btrfs_fs(void)
2502 {
2503         int i;
2504
2505         for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2506                 if (!mod_init_result[i])
2507                         continue;
2508                 if (mod_init_seq[i].exit_func)
2509                         mod_init_seq[i].exit_func();
2510                 mod_init_result[i] = false;
2511         }
2512 }
2513
2514 static void __exit exit_btrfs_fs(void)
2515 {
2516         btrfs_exit_btrfs_fs();
2517 }
2518
2519 static int __init init_btrfs_fs(void)
2520 {
2521         int ret;
2522         int i;
2523
2524         for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2525                 ASSERT(!mod_init_result[i]);
2526                 ret = mod_init_seq[i].init_func();
2527                 if (ret < 0) {
2528                         btrfs_exit_btrfs_fs();
2529                         return ret;
2530                 }
2531                 mod_init_result[i] = true;
2532         }
2533         return 0;
2534 }
2535
2536 late_initcall(init_btrfs_fs);
2537 module_exit(exit_btrfs_fs)
2538
2539 MODULE_LICENSE("GPL");
2540 MODULE_SOFTDEP("pre: crc32c");
2541 MODULE_SOFTDEP("pre: xxhash64");
2542 MODULE_SOFTDEP("pre: sha256");
2543 MODULE_SOFTDEP("pre: blake2b-256");