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 "bio.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 #include "extent-tree.h"
  62 #define CREATE_TRACE_POINTS
  63 #include <trace/events/btrfs.h>
  64
  65 static const struct super_operations btrfs_super_ops;
  66
  67 /*
  68  * Types for mounting the default subvolume and a subvolume explicitly
  69  * requested by subvol=/path. That way the callchain is straightforward and we
  70  * don't have to play tricks with the mount options and recursive calls to
  71  * btrfs_mount.
  72  *
  73  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
  74  */
  75 static struct file_system_type btrfs_fs_type;
  76 static struct file_system_type btrfs_root_fs_type;
  77
  78 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  79
  80 static void btrfs_put_super(struct super_block *sb)
  81 {
  82         close_ctree(btrfs_sb(sb));
  83 }
  84
  85 enum {
  86         Opt_acl, Opt_noacl,
  87         Opt_clear_cache,
  88         Opt_commit_interval,
  89         Opt_compress,
  90         Opt_compress_force,
  91         Opt_compress_force_type,
  92         Opt_compress_type,
  93         Opt_degraded,
  94         Opt_device,
  95         Opt_fatal_errors,
  96         Opt_flushoncommit, Opt_noflushoncommit,
  97         Opt_max_inline,
  98         Opt_barrier, Opt_nobarrier,
  99         Opt_datacow, Opt_nodatacow,
 100         Opt_datasum, Opt_nodatasum,
 101         Opt_defrag, Opt_nodefrag,
 102         Opt_discard, Opt_nodiscard,
 103         Opt_discard_mode,
 104         Opt_norecovery,
 105         Opt_ratio,
 106         Opt_rescan_uuid_tree,
 107         Opt_skip_balance,
 108         Opt_space_cache, Opt_no_space_cache,
 109         Opt_space_cache_version,
 110         Opt_ssd, Opt_nossd,
 111         Opt_ssd_spread, Opt_nossd_spread,
 112         Opt_subvol,
 113         Opt_subvol_empty,
 114         Opt_subvolid,
 115         Opt_thread_pool,
 116         Opt_treelog, Opt_notreelog,
 117         Opt_user_subvol_rm_allowed,
 118
 119         /* Rescue options */
 120         Opt_rescue,
 121         Opt_usebackuproot,
 122         Opt_nologreplay,
 123         Opt_ignorebadroots,
 124         Opt_ignoredatacsums,
 125         Opt_rescue_all,
 126
 127         /* Deprecated options */
 128         Opt_recovery,
 129         Opt_inode_cache, Opt_noinode_cache,
 130
 131         /* Debugging options */
 132         Opt_check_integrity,
 133         Opt_check_integrity_including_extent_data,
 134         Opt_check_integrity_print_mask,
 135         Opt_enospc_debug, Opt_noenospc_debug,
 136 #ifdef CONFIG_BTRFS_DEBUG
 137         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 138 #endif
 139 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 140         Opt_ref_verify,
 141 #endif
 142         Opt_err,
 143 };
 144
 145 static const match_table_t tokens = {
 146         {Opt_acl, "acl"},
 147         {Opt_noacl, "noacl"},
 148         {Opt_clear_cache, "clear_cache"},
 149         {Opt_commit_interval, "commit=%u"},
 150         {Opt_compress, "compress"},
 151         {Opt_compress_type, "compress=%s"},
 152         {Opt_compress_force, "compress-force"},
 153         {Opt_compress_force_type, "compress-force=%s"},
 154         {Opt_degraded, "degraded"},
 155         {Opt_device, "device=%s"},
 156         {Opt_fatal_errors, "fatal_errors=%s"},
 157         {Opt_flushoncommit, "flushoncommit"},
 158         {Opt_noflushoncommit, "noflushoncommit"},
 159         {Opt_inode_cache, "inode_cache"},
 160         {Opt_noinode_cache, "noinode_cache"},
 161         {Opt_max_inline, "max_inline=%s"},
 162         {Opt_barrier, "barrier"},
 163         {Opt_nobarrier, "nobarrier"},
 164         {Opt_datacow, "datacow"},
 165         {Opt_nodatacow, "nodatacow"},
 166         {Opt_datasum, "datasum"},
 167         {Opt_nodatasum, "nodatasum"},
 168         {Opt_defrag, "autodefrag"},
 169         {Opt_nodefrag, "noautodefrag"},
 170         {Opt_discard, "discard"},
 171         {Opt_discard_mode, "discard=%s"},
 172         {Opt_nodiscard, "nodiscard"},
 173         {Opt_norecovery, "norecovery"},
 174         {Opt_ratio, "metadata_ratio=%u"},
 175         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 176         {Opt_skip_balance, "skip_balance"},
 177         {Opt_space_cache, "space_cache"},
 178         {Opt_no_space_cache, "nospace_cache"},
 179         {Opt_space_cache_version, "space_cache=%s"},
 180         {Opt_ssd, "ssd"},
 181         {Opt_nossd, "nossd"},
 182         {Opt_ssd_spread, "ssd_spread"},
 183         {Opt_nossd_spread, "nossd_spread"},
 184         {Opt_subvol, "subvol=%s"},
 185         {Opt_subvol_empty, "subvol="},
 186         {Opt_subvolid, "subvolid=%s"},
 187         {Opt_thread_pool, "thread_pool=%u"},
 188         {Opt_treelog, "treelog"},
 189         {Opt_notreelog, "notreelog"},
 190         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 191
 192         /* Rescue options */
 193         {Opt_rescue, "rescue=%s"},
 194         /* Deprecated, with alias rescue=nologreplay */
 195         {Opt_nologreplay, "nologreplay"},
 196         /* Deprecated, with alias rescue=usebackuproot */
 197         {Opt_usebackuproot, "usebackuproot"},
 198
 199         /* Deprecated options */
 200         {Opt_recovery, "recovery"},
 201
 202         /* Debugging options */
 203         {Opt_check_integrity, "check_int"},
 204         {Opt_check_integrity_including_extent_data, "check_int_data"},
 205         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
 206         {Opt_enospc_debug, "enospc_debug"},
 207         {Opt_noenospc_debug, "noenospc_debug"},
 208 #ifdef CONFIG_BTRFS_DEBUG
 209         {Opt_fragment_data, "fragment=data"},
 210         {Opt_fragment_metadata, "fragment=metadata"},
 211         {Opt_fragment_all, "fragment=all"},
 212 #endif
 213 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 214         {Opt_ref_verify, "ref_verify"},
 215 #endif
 216         {Opt_err, NULL},
 217 };
 218
 219 static const match_table_t rescue_tokens = {
 220         {Opt_usebackuproot, "usebackuproot"},
 221         {Opt_nologreplay, "nologreplay"},
 222         {Opt_ignorebadroots, "ignorebadroots"},
 223         {Opt_ignorebadroots, "ibadroots"},
 224         {Opt_ignoredatacsums, "ignoredatacsums"},
 225         {Opt_ignoredatacsums, "idatacsums"},
 226         {Opt_rescue_all, "all"},
 227         {Opt_err, NULL},
 228 };
 229
 230 static bool check_ro_option(struct btrfs_fs_info *fs_info, unsigned long opt,
 231                             const char *opt_name)
 232 {
 233         if (fs_info->mount_opt & opt) {
 234                 btrfs_err(fs_info, "%s must be used with ro mount option",
 235                           opt_name);
 236                 return true;
 237         }
 238         return false;
 239 }
 240
 241 static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
 242 {
 243         char *opts;
 244         char *orig;
 245         char *p;
 246         substring_t args[MAX_OPT_ARGS];
 247         int ret = 0;
 248
 249         opts = kstrdup(options, GFP_KERNEL);
 250         if (!opts)
 251                 return -ENOMEM;
 252         orig = opts;
 253
 254         while ((p = strsep(&opts, ":")) != NULL) {
 255                 int token;
 256
 257                 if (!*p)
 258                         continue;
 259                 token = match_token(p, rescue_tokens, args);
 260                 switch (token){
 261                 case Opt_usebackuproot:
 262                         btrfs_info(info,
 263                                    "trying to use backup root at mount time");
 264                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 265                         break;
 266                 case Opt_nologreplay:
 267                         btrfs_set_and_info(info, NOLOGREPLAY,
 268                                            "disabling log replay at mount time");
 269                         break;
 270                 case Opt_ignorebadroots:
 271                         btrfs_set_and_info(info, IGNOREBADROOTS,
 272                                            "ignoring bad roots");
 273                         break;
 274                 case Opt_ignoredatacsums:
 275                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 276                                            "ignoring data csums");
 277                         break;
 278                 case Opt_rescue_all:
 279                         btrfs_info(info, "enabling all of the rescue options");
 280                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 281                                            "ignoring data csums");
 282                         btrfs_set_and_info(info, IGNOREBADROOTS,
 283                                            "ignoring bad roots");
 284                         btrfs_set_and_info(info, NOLOGREPLAY,
 285                                            "disabling log replay at mount time");
 286                         break;
 287                 case Opt_err:
 288                         btrfs_info(info, "unrecognized rescue option '%s'", p);
 289                         ret = -EINVAL;
 290                         goto out;
 291                 default:
 292                         break;
 293                 }
 294
 295         }
 296 out:
 297         kfree(orig);
 298         return ret;
 299 }
 300
 301 /*
 302  * Regular mount options parser.  Everything that is needed only when
 303  * reading in a new superblock is parsed here.
 304  * XXX JDM: This needs to be cleaned up for remount.
 305  */
 306 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 307                         unsigned long new_flags)
 308 {
 309         substring_t args[MAX_OPT_ARGS];
 310         char *p, *num;
 311         int intarg;
 312         int ret = 0;
 313         char *compress_type;
 314         bool compress_force = false;
 315         enum btrfs_compression_type saved_compress_type;
 316         int saved_compress_level;
 317         bool saved_compress_force;
 318         int no_compress = 0;
 319         const bool remounting = test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state);
 320
 321         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 322                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 323         else if (btrfs_free_space_cache_v1_active(info)) {
 324                 if (btrfs_is_zoned(info)) {
 325                         btrfs_info(info,
 326                         "zoned: clearing existing space cache");
 327                         btrfs_set_super_cache_generation(info->super_copy, 0);
 328                 } else {
 329                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 330                 }
 331         }
 332
 333         /*
 334          * Even the options are empty, we still need to do extra check
 335          * against new flags
 336          */
 337         if (!options)
 338                 goto check;
 339
 340         while ((p = strsep(&options, ",")) != NULL) {
 341                 int token;
 342                 if (!*p)
 343                         continue;
 344
 345                 token = match_token(p, tokens, args);
 346                 switch (token) {
 347                 case Opt_degraded:
 348                         btrfs_info(info, "allowing degraded mounts");
 349                         btrfs_set_opt(info->mount_opt, DEGRADED);
 350                         break;
 351                 case Opt_subvol:
 352                 case Opt_subvol_empty:
 353                 case Opt_subvolid:
 354                 case Opt_device:
 355                         /*
 356                          * These are parsed by btrfs_parse_subvol_options or
 357                          * btrfs_parse_device_options and can be ignored here.
 358                          */
 359                         break;
 360                 case Opt_nodatasum:
 361                         btrfs_set_and_info(info, NODATASUM,
 362                                            "setting nodatasum");
 363                         break;
 364                 case Opt_datasum:
 365                         if (btrfs_test_opt(info, NODATASUM)) {
 366                                 if (btrfs_test_opt(info, NODATACOW))
 367                                         btrfs_info(info,
 368                                                    "setting datasum, datacow enabled");
 369                                 else
 370                                         btrfs_info(info, "setting datasum");
 371                         }
 372                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 373                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 374                         break;
 375                 case Opt_nodatacow:
 376                         if (!btrfs_test_opt(info, NODATACOW)) {
 377                                 if (!btrfs_test_opt(info, COMPRESS) ||
 378                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 379                                         btrfs_info(info,
 380                                                    "setting nodatacow, compression disabled");
 381                                 } else {
 382                                         btrfs_info(info, "setting nodatacow");
 383                                 }
 384                         }
 385                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 386                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 387                         btrfs_set_opt(info->mount_opt, NODATACOW);
 388                         btrfs_set_opt(info->mount_opt, NODATASUM);
 389                         break;
 390                 case Opt_datacow:
 391                         btrfs_clear_and_info(info, NODATACOW,
 392                                              "setting datacow");
 393                         break;
 394                 case Opt_compress_force:
 395                 case Opt_compress_force_type:
 396                         compress_force = true;
 397                         fallthrough;
 398                 case Opt_compress:
 399                 case Opt_compress_type:
 400                         saved_compress_type = btrfs_test_opt(info,
 401                                                              COMPRESS) ?
 402                                 info->compress_type : BTRFS_COMPRESS_NONE;
 403                         saved_compress_force =
 404                                 btrfs_test_opt(info, FORCE_COMPRESS);
 405                         saved_compress_level = info->compress_level;
 406                         if (token == Opt_compress ||
 407                             token == Opt_compress_force ||
 408                             strncmp(args[0].from, "zlib", 4) == 0) {
 409                                 compress_type = "zlib";
 410
 411                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 412                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 413                                 /*
 414                                  * args[0] contains uninitialized data since
 415                                  * for these tokens we don't expect any
 416                                  * parameter.
 417                                  */
 418                                 if (token != Opt_compress &&
 419                                     token != Opt_compress_force)
 420                                         info->compress_level =
 421                                           btrfs_compress_str2level(
 422                                                         BTRFS_COMPRESS_ZLIB,
 423                                                         args[0].from + 4);
 424                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 425                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 426                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 427                                 no_compress = 0;
 428                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 429                                 compress_type = "lzo";
 430                                 info->compress_type = BTRFS_COMPRESS_LZO;
 431                                 info->compress_level = 0;
 432                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 433                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 434                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 435                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 436                                 no_compress = 0;
 437                         } else if (strncmp(args[0].from, "zstd", 4) == 0) {
 438                                 compress_type = "zstd";
 439                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 440                                 info->compress_level =
 441                                         btrfs_compress_str2level(
 442                                                          BTRFS_COMPRESS_ZSTD,
 443                                                          args[0].from + 4);
 444                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 445                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 446                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 447                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 448                                 no_compress = 0;
 449                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 450                                 compress_type = "no";
 451                                 info->compress_level = 0;
 452                                 info->compress_type = 0;
 453                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 454                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 455                                 compress_force = false;
 456                                 no_compress++;
 457                         } else {
 458                                 btrfs_err(info, "unrecognized compression value %s",
 459                                           args[0].from);
 460                                 ret = -EINVAL;
 461                                 goto out;
 462                         }
 463
 464                         if (compress_force) {
 465                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 466                         } else {
 467                                 /*
 468                                  * If we remount from compress-force=xxx to
 469                                  * compress=xxx, we need clear FORCE_COMPRESS
 470                                  * flag, otherwise, there is no way for users
 471                                  * to disable forcible compression separately.
 472                                  */
 473                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 474                         }
 475                         if (no_compress == 1) {
 476                                 btrfs_info(info, "use no compression");
 477                         } else if ((info->compress_type != saved_compress_type) ||
 478                                    (compress_force != saved_compress_force) ||
 479                                    (info->compress_level != saved_compress_level)) {
 480                                 btrfs_info(info, "%s %s compression, level %d",
 481                                            (compress_force) ? "force" : "use",
 482                                            compress_type, info->compress_level);
 483                         }
 484                         compress_force = false;
 485                         break;
 486                 case Opt_ssd:
 487                         btrfs_set_and_info(info, SSD,
 488                                            "enabling ssd optimizations");
 489                         btrfs_clear_opt(info->mount_opt, NOSSD);
 490                         break;
 491                 case Opt_ssd_spread:
 492                         btrfs_set_and_info(info, SSD,
 493                                            "enabling ssd optimizations");
 494                         btrfs_set_and_info(info, SSD_SPREAD,
 495                                            "using spread ssd allocation scheme");
 496                         btrfs_clear_opt(info->mount_opt, NOSSD);
 497                         break;
 498                 case Opt_nossd:
 499                         btrfs_set_opt(info->mount_opt, NOSSD);
 500                         btrfs_clear_and_info(info, SSD,
 501                                              "not using ssd optimizations");
 502                         fallthrough;
 503                 case Opt_nossd_spread:
 504                         btrfs_clear_and_info(info, SSD_SPREAD,
 505                                              "not using spread ssd allocation scheme");
 506                         break;
 507                 case Opt_barrier:
 508                         btrfs_clear_and_info(info, NOBARRIER,
 509                                              "turning on barriers");
 510                         break;
 511                 case Opt_nobarrier:
 512                         btrfs_set_and_info(info, NOBARRIER,
 513                                            "turning off barriers");
 514                         break;
 515                 case Opt_thread_pool:
 516                         ret = match_int(&args[0], &intarg);
 517                         if (ret) {
 518                                 btrfs_err(info, "unrecognized thread_pool value %s",
 519                                           args[0].from);
 520                                 goto out;
 521                         } else if (intarg == 0) {
 522                                 btrfs_err(info, "invalid value 0 for thread_pool");
 523                                 ret = -EINVAL;
 524                                 goto out;
 525                         }
 526                         info->thread_pool_size = intarg;
 527                         break;
 528                 case Opt_max_inline:
 529                         num = match_strdup(&args[0]);
 530                         if (num) {
 531                                 info->max_inline = memparse(num, NULL);
 532                                 kfree(num);
 533
 534                                 if (info->max_inline) {
 535                                         info->max_inline = min_t(u64,
 536                                                 info->max_inline,
 537                                                 info->sectorsize);
 538                                 }
 539                                 btrfs_info(info, "max_inline at %llu",
 540                                            info->max_inline);
 541                         } else {
 542                                 ret = -ENOMEM;
 543                                 goto out;
 544                         }
 545                         break;
 546                 case Opt_acl:
 547 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 548                         info->sb->s_flags |= SB_POSIXACL;
 549                         break;
 550 #else
 551                         btrfs_err(info, "support for ACL not compiled in!");
 552                         ret = -EINVAL;
 553                         goto out;
 554 #endif
 555                 case Opt_noacl:
 556                         info->sb->s_flags &= ~SB_POSIXACL;
 557                         break;
 558                 case Opt_notreelog:
 559                         btrfs_set_and_info(info, NOTREELOG,
 560                                            "disabling tree log");
 561                         break;
 562                 case Opt_treelog:
 563                         btrfs_clear_and_info(info, NOTREELOG,
 564                                              "enabling tree log");
 565                         break;
 566                 case Opt_norecovery:
 567                 case Opt_nologreplay:
 568                         btrfs_warn(info,
 569                 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
 570                         btrfs_set_and_info(info, NOLOGREPLAY,
 571                                            "disabling log replay at mount time");
 572                         break;
 573                 case Opt_flushoncommit:
 574                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 575                                            "turning on flush-on-commit");
 576                         break;
 577                 case Opt_noflushoncommit:
 578                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 579                                              "turning off flush-on-commit");
 580                         break;
 581                 case Opt_ratio:
 582                         ret = match_int(&args[0], &intarg);
 583                         if (ret) {
 584                                 btrfs_err(info, "unrecognized metadata_ratio value %s",
 585                                           args[0].from);
 586                                 goto out;
 587                         }
 588                         info->metadata_ratio = intarg;
 589                         btrfs_info(info, "metadata ratio %u",
 590                                    info->metadata_ratio);
 591                         break;
 592                 case Opt_discard:
 593                 case Opt_discard_mode:
 594                         if (token == Opt_discard ||
 595                             strcmp(args[0].from, "sync") == 0) {
 596                                 btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
 597                                 btrfs_set_and_info(info, DISCARD_SYNC,
 598                                                    "turning on sync discard");
 599                         } else if (strcmp(args[0].from, "async") == 0) {
 600                                 btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
 601                                 btrfs_set_and_info(info, DISCARD_ASYNC,
 602                                                    "turning on async discard");
 603                         } else {
 604                                 btrfs_err(info, "unrecognized discard mode value %s",
 605                                           args[0].from);
 606                                 ret = -EINVAL;
 607                                 goto out;
 608                         }
 609                         btrfs_clear_opt(info->mount_opt, NODISCARD);
 610                         break;
 611                 case Opt_nodiscard:
 612                         btrfs_clear_and_info(info, DISCARD_SYNC,
 613                                              "turning off discard");
 614                         btrfs_clear_and_info(info, DISCARD_ASYNC,
 615                                              "turning off async discard");
 616                         btrfs_set_opt(info->mount_opt, NODISCARD);
 617                         break;
 618                 case Opt_space_cache:
 619                 case Opt_space_cache_version:
 620                         /*
 621                          * We already set FREE_SPACE_TREE above because we have
 622                          * compat_ro(FREE_SPACE_TREE) set, and we aren't going
 623                          * to allow v1 to be set for extent tree v2, simply
 624                          * ignore this setting if we're extent tree v2.
 625                          */
 626                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 627                                 break;
 628                         if (token == Opt_space_cache ||
 629                             strcmp(args[0].from, "v1") == 0) {
 630                                 btrfs_clear_opt(info->mount_opt,
 631                                                 FREE_SPACE_TREE);
 632                                 btrfs_set_and_info(info, SPACE_CACHE,
 633                                            "enabling disk space caching");
 634                         } else if (strcmp(args[0].from, "v2") == 0) {
 635                                 btrfs_clear_opt(info->mount_opt,
 636                                                 SPACE_CACHE);
 637                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 638                                                    "enabling free space tree");
 639                         } else {
 640                                 btrfs_err(info, "unrecognized space_cache value %s",
 641                                           args[0].from);
 642                                 ret = -EINVAL;
 643                                 goto out;
 644                         }
 645                         break;
 646                 case Opt_rescan_uuid_tree:
 647                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 648                         break;
 649                 case Opt_no_space_cache:
 650                         /*
 651                          * We cannot operate without the free space tree with
 652                          * extent tree v2, ignore this option.
 653                          */
 654                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 655                                 break;
 656                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 657                                 btrfs_clear_and_info(info, SPACE_CACHE,
 658                                              "disabling disk space caching");
 659                         }
 660                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 661                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 662                                              "disabling free space tree");
 663                         }
 664                         break;
 665                 case Opt_inode_cache:
 666                 case Opt_noinode_cache:
 667                         btrfs_warn(info,
 668         "the 'inode_cache' option is deprecated and has no effect since 5.11");
 669                         break;
 670                 case Opt_clear_cache:
 671                         /*
 672                          * We cannot clear the free space tree with extent tree
 673                          * v2, ignore this option.
 674                          */
 675                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 676                                 break;
 677                         btrfs_set_and_info(info, CLEAR_CACHE,
 678                                            "force clearing of disk cache");
 679                         break;
 680                 case Opt_user_subvol_rm_allowed:
 681                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 682                         break;
 683                 case Opt_enospc_debug:
 684                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 685                         break;
 686                 case Opt_noenospc_debug:
 687                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 688                         break;
 689                 case Opt_defrag:
 690                         btrfs_set_and_info(info, AUTO_DEFRAG,
 691                                            "enabling auto defrag");
 692                         break;
 693                 case Opt_nodefrag:
 694                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 695                                              "disabling auto defrag");
 696                         break;
 697                 case Opt_recovery:
 698                 case Opt_usebackuproot:
 699                         btrfs_warn(info,
 700                         "'%s' is deprecated, use 'rescue=usebackuproot' instead",
 701                                    token == Opt_recovery ? "recovery" :
 702                                    "usebackuproot");
 703                         btrfs_info(info,
 704                                    "trying to use backup root at mount time");
 705                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 706                         break;
 707                 case Opt_skip_balance:
 708                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 709                         break;
 710 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 711                 case Opt_check_integrity_including_extent_data:
 712                         btrfs_info(info,
 713                                    "enabling check integrity including extent data");
 714                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY_DATA);
 715                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 716                         break;
 717                 case Opt_check_integrity:
 718                         btrfs_info(info, "enabling check integrity");
 719                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 720                         break;
 721                 case Opt_check_integrity_print_mask:
 722                         ret = match_int(&args[0], &intarg);
 723                         if (ret) {
 724                                 btrfs_err(info,
 725                                 "unrecognized check_integrity_print_mask value %s",
 726                                         args[0].from);
 727                                 goto out;
 728                         }
 729                         info->check_integrity_print_mask = intarg;
 730                         btrfs_info(info, "check_integrity_print_mask 0x%x",
 731                                    info->check_integrity_print_mask);
 732                         break;
 733 #else
 734                 case Opt_check_integrity_including_extent_data:
 735                 case Opt_check_integrity:
 736                 case Opt_check_integrity_print_mask:
 737                         btrfs_err(info,
 738                                   "support for check_integrity* not compiled in!");
 739                         ret = -EINVAL;
 740                         goto out;
 741 #endif
 742                 case Opt_fatal_errors:
 743                         if (strcmp(args[0].from, "panic") == 0) {
 744                                 btrfs_set_opt(info->mount_opt,
 745                                               PANIC_ON_FATAL_ERROR);
 746                         } else if (strcmp(args[0].from, "bug") == 0) {
 747                                 btrfs_clear_opt(info->mount_opt,
 748                                               PANIC_ON_FATAL_ERROR);
 749                         } else {
 750                                 btrfs_err(info, "unrecognized fatal_errors value %s",
 751                                           args[0].from);
 752                                 ret = -EINVAL;
 753                                 goto out;
 754                         }
 755                         break;
 756                 case Opt_commit_interval:
 757                         intarg = 0;
 758                         ret = match_int(&args[0], &intarg);
 759                         if (ret) {
 760                                 btrfs_err(info, "unrecognized commit_interval value %s",
 761                                           args[0].from);
 762                                 ret = -EINVAL;
 763                                 goto out;
 764                         }
 765                         if (intarg == 0) {
 766                                 btrfs_info(info,
 767                                            "using default commit interval %us",
 768                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 769                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
 770                         } else if (intarg > 300) {
 771                                 btrfs_warn(info, "excessive commit interval %d",
 772                                            intarg);
 773                         }
 774                         info->commit_interval = intarg;
 775                         break;
 776                 case Opt_rescue:
 777                         ret = parse_rescue_options(info, args[0].from);
 778                         if (ret < 0) {
 779                                 btrfs_err(info, "unrecognized rescue value %s",
 780                                           args[0].from);
 781                                 goto out;
 782                         }
 783                         break;
 784 #ifdef CONFIG_BTRFS_DEBUG
 785                 case Opt_fragment_all:
 786                         btrfs_info(info, "fragmenting all space");
 787                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 788                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 789                         break;
 790                 case Opt_fragment_metadata:
 791                         btrfs_info(info, "fragmenting metadata");
 792                         btrfs_set_opt(info->mount_opt,
 793                                       FRAGMENT_METADATA);
 794                         break;
 795                 case Opt_fragment_data:
 796                         btrfs_info(info, "fragmenting data");
 797                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 798                         break;
 799 #endif
 800 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 801                 case Opt_ref_verify:
 802                         btrfs_info(info, "doing ref verification");
 803                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 804                         break;
 805 #endif
 806                 case Opt_err:
 807                         btrfs_err(info, "unrecognized mount option '%s'", p);
 808                         ret = -EINVAL;
 809                         goto out;
 810                 default:
 811                         break;
 812                 }
 813         }
 814 check:
 815         /* We're read-only, don't have to check. */
 816         if (new_flags & SB_RDONLY)
 817                 goto out;
 818
 819         if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
 820             check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
 821             check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))
 822                 ret = -EINVAL;
 823 out:
 824         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 825             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 826             !btrfs_test_opt(info, CLEAR_CACHE)) {
 827                 btrfs_err(info, "cannot disable free space tree");
 828                 ret = -EINVAL;
 829         }
 830         if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
 831              !btrfs_test_opt(info, FREE_SPACE_TREE)) {
 832                 btrfs_err(info, "cannot disable free space tree with block-group-tree feature");
 833                 ret = -EINVAL;
 834         }
 835         if (!ret)
 836                 ret = btrfs_check_mountopts_zoned(info);
 837         if (!ret && !remounting) {
 838                 if (btrfs_test_opt(info, SPACE_CACHE))
 839                         btrfs_info(info, "disk space caching is enabled");
 840                 if (btrfs_test_opt(info, FREE_SPACE_TREE))
 841                         btrfs_info(info, "using free space tree");
 842         }
 843         return ret;
 844 }
 845
 846 /*
 847  * Parse mount options that are required early in the mount process.
 848  *
 849  * All other options will be parsed on much later in the mount process and
 850  * only when we need to allocate a new super block.
 851  */
 852 static int btrfs_parse_device_options(const char *options, fmode_t flags,
 853                                       void *holder)
 854 {
 855         substring_t args[MAX_OPT_ARGS];
 856         char *device_name, *opts, *orig, *p;
 857         struct btrfs_device *device = NULL;
 858         int error = 0;
 859
 860         lockdep_assert_held(&uuid_mutex);
 861
 862         if (!options)
 863                 return 0;
 864
 865         /*
 866          * strsep changes the string, duplicate it because btrfs_parse_options
 867          * gets called later
 868          */
 869         opts = kstrdup(options, GFP_KERNEL);
 870         if (!opts)
 871                 return -ENOMEM;
 872         orig = opts;
 873
 874         while ((p = strsep(&opts, ",")) != NULL) {
 875                 int token;
 876
 877                 if (!*p)
 878                         continue;
 879
 880                 token = match_token(p, tokens, args);
 881                 if (token == Opt_device) {
 882                         device_name = match_strdup(&args[0]);
 883                         if (!device_name) {
 884                                 error = -ENOMEM;
 885                                 goto out;
 886                         }
 887                         device = btrfs_scan_one_device(device_name, flags,
 888                                         holder);
 889                         kfree(device_name);
 890                         if (IS_ERR(device)) {
 891                                 error = PTR_ERR(device);
 892                                 goto out;
 893                         }
 894                 }
 895         }
 896
 897 out:
 898         kfree(orig);
 899         return error;
 900 }
 901
 902 /*
 903  * Parse mount options that are related to subvolume id
 904  *
 905  * The value is later passed to mount_subvol()
 906  */
 907 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
 908                 u64 *subvol_objectid)
 909 {
 910         substring_t args[MAX_OPT_ARGS];
 911         char *opts, *orig, *p;
 912         int error = 0;
 913         u64 subvolid;
 914
 915         if (!options)
 916                 return 0;
 917
 918         /*
 919          * strsep changes the string, duplicate it because
 920          * btrfs_parse_device_options gets called later
 921          */
 922         opts = kstrdup(options, GFP_KERNEL);
 923         if (!opts)
 924                 return -ENOMEM;
 925         orig = opts;
 926
 927         while ((p = strsep(&opts, ",")) != NULL) {
 928                 int token;
 929                 if (!*p)
 930                         continue;
 931
 932                 token = match_token(p, tokens, args);
 933                 switch (token) {
 934                 case Opt_subvol:
 935                         kfree(*subvol_name);
 936                         *subvol_name = match_strdup(&args[0]);
 937                         if (!*subvol_name) {
 938                                 error = -ENOMEM;
 939                                 goto out;
 940                         }
 941                         break;
 942                 case Opt_subvolid:
 943                         error = match_u64(&args[0], &subvolid);
 944                         if (error)
 945                                 goto out;
 946
 947                         /* we want the original fs_tree */
 948                         if (subvolid == 0)
 949                                 subvolid = BTRFS_FS_TREE_OBJECTID;
 950
 951                         *subvol_objectid = subvolid;
 952                         break;
 953                 default:
 954                         break;
 955                 }
 956         }
 957
 958 out:
 959         kfree(orig);
 960         return error;
 961 }
 962
 963 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 964                                           u64 subvol_objectid)
 965 {
 966         struct btrfs_root *root = fs_info->tree_root;
 967         struct btrfs_root *fs_root = NULL;
 968         struct btrfs_root_ref *root_ref;
 969         struct btrfs_inode_ref *inode_ref;
 970         struct btrfs_key key;
 971         struct btrfs_path *path = NULL;
 972         char *name = NULL, *ptr;
 973         u64 dirid;
 974         int len;
 975         int ret;
 976
 977         path = btrfs_alloc_path();
 978         if (!path) {
 979                 ret = -ENOMEM;
 980                 goto err;
 981         }
 982
 983         name = kmalloc(PATH_MAX, GFP_KERNEL);
 984         if (!name) {
 985                 ret = -ENOMEM;
 986                 goto err;
 987         }
 988         ptr = name + PATH_MAX - 1;
 989         ptr[0] = '\0';
 990
 991         /*
 992          * Walk up the subvolume trees in the tree of tree roots by root
 993          * backrefs until we hit the top-level subvolume.
 994          */
 995         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 996                 key.objectid = subvol_objectid;
 997                 key.type = BTRFS_ROOT_BACKREF_KEY;
 998                 key.offset = (u64)-1;
 999
1000                 ret = btrfs_search_backwards(root, &key, path);
1001                 if (ret < 0) {
1002                         goto err;
1003                 } else if (ret > 0) {
1004                         ret = -ENOENT;
1005                         goto err;
1006                 }
1007
1008                 subvol_objectid = key.offset;
1009
1010                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1011                                           struct btrfs_root_ref);
1012                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1013                 ptr -= len + 1;
1014                 if (ptr < name) {
1015                         ret = -ENAMETOOLONG;
1016                         goto err;
1017                 }
1018                 read_extent_buffer(path->nodes[0], ptr + 1,
1019                                    (unsigned long)(root_ref + 1), len);
1020                 ptr[0] = '/';
1021                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1022                 btrfs_release_path(path);
1023
1024                 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
1025                 if (IS_ERR(fs_root)) {
1026                         ret = PTR_ERR(fs_root);
1027                         fs_root = NULL;
1028                         goto err;
1029                 }
1030
1031                 /*
1032                  * Walk up the filesystem tree by inode refs until we hit the
1033                  * root directory.
1034                  */
1035                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1036                         key.objectid = dirid;
1037                         key.type = BTRFS_INODE_REF_KEY;
1038                         key.offset = (u64)-1;
1039
1040                         ret = btrfs_search_backwards(fs_root, &key, path);
1041                         if (ret < 0) {
1042                                 goto err;
1043                         } else if (ret > 0) {
1044                                 ret = -ENOENT;
1045                                 goto err;
1046                         }
1047
1048                         dirid = key.offset;
1049
1050                         inode_ref = btrfs_item_ptr(path->nodes[0],
1051                                                    path->slots[0],
1052                                                    struct btrfs_inode_ref);
1053                         len = btrfs_inode_ref_name_len(path->nodes[0],
1054                                                        inode_ref);
1055                         ptr -= len + 1;
1056                         if (ptr < name) {
1057                                 ret = -ENAMETOOLONG;
1058                                 goto err;
1059                         }
1060                         read_extent_buffer(path->nodes[0], ptr + 1,
1061                                            (unsigned long)(inode_ref + 1), len);
1062                         ptr[0] = '/';
1063                         btrfs_release_path(path);
1064                 }
1065                 btrfs_put_root(fs_root);
1066                 fs_root = NULL;
1067         }
1068
1069         btrfs_free_path(path);
1070         if (ptr == name + PATH_MAX - 1) {
1071                 name[0] = '/';
1072                 name[1] = '\0';
1073         } else {
1074                 memmove(name, ptr, name + PATH_MAX - ptr);
1075         }
1076         return name;
1077
1078 err:
1079         btrfs_put_root(fs_root);
1080         btrfs_free_path(path);
1081         kfree(name);
1082         return ERR_PTR(ret);
1083 }
1084
1085 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1086 {
1087         struct btrfs_root *root = fs_info->tree_root;
1088         struct btrfs_dir_item *di;
1089         struct btrfs_path *path;
1090         struct btrfs_key location;
1091         struct fscrypt_str name = FSTR_INIT("default", 7);
1092         u64 dir_id;
1093
1094         path = btrfs_alloc_path();
1095         if (!path)
1096                 return -ENOMEM;
1097
1098         /*
1099          * Find the "default" dir item which points to the root item that we
1100          * will mount by default if we haven't been given a specific subvolume
1101          * to mount.
1102          */
1103         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1104         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
1105         if (IS_ERR(di)) {
1106                 btrfs_free_path(path);
1107                 return PTR_ERR(di);
1108         }
1109         if (!di) {
1110                 /*
1111                  * Ok the default dir item isn't there.  This is weird since
1112                  * it's always been there, but don't freak out, just try and
1113                  * mount the top-level subvolume.
1114                  */
1115                 btrfs_free_path(path);
1116                 *objectid = BTRFS_FS_TREE_OBJECTID;
1117                 return 0;
1118         }
1119
1120         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1121         btrfs_free_path(path);
1122         *objectid = location.objectid;
1123         return 0;
1124 }
1125
1126 static int btrfs_fill_super(struct super_block *sb,
1127                             struct btrfs_fs_devices *fs_devices,
1128                             void *data)
1129 {
1130         struct inode *inode;
1131         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1132         int err;
1133
1134         sb->s_maxbytes = MAX_LFS_FILESIZE;
1135         sb->s_magic = BTRFS_SUPER_MAGIC;
1136         sb->s_op = &btrfs_super_ops;
1137         sb->s_d_op = &btrfs_dentry_operations;
1138         sb->s_export_op = &btrfs_export_ops;
1139 #ifdef CONFIG_FS_VERITY
1140         sb->s_vop = &btrfs_verityops;
1141 #endif
1142         sb->s_xattr = btrfs_xattr_handlers;
1143         sb->s_time_gran = 1;
1144 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1145         sb->s_flags |= SB_POSIXACL;
1146 #endif
1147         sb->s_flags |= SB_I_VERSION;
1148         sb->s_iflags |= SB_I_CGROUPWB;
1149
1150         err = super_setup_bdi(sb);
1151         if (err) {
1152                 btrfs_err(fs_info, "super_setup_bdi failed");
1153                 return err;
1154         }
1155
1156         err = open_ctree(sb, fs_devices, (char *)data);
1157         if (err) {
1158                 btrfs_err(fs_info, "open_ctree failed");
1159                 return err;
1160         }
1161
1162         inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1163         if (IS_ERR(inode)) {
1164                 err = PTR_ERR(inode);
1165                 btrfs_handle_fs_error(fs_info, err, NULL);
1166                 goto fail_close;
1167         }
1168
1169         sb->s_root = d_make_root(inode);
1170         if (!sb->s_root) {
1171                 err = -ENOMEM;
1172                 goto fail_close;
1173         }
1174
1175         sb->s_flags |= SB_ACTIVE;
1176         return 0;
1177
1178 fail_close:
1179         close_ctree(fs_info);
1180         return err;
1181 }
1182
1183 int btrfs_sync_fs(struct super_block *sb, int wait)
1184 {
1185         struct btrfs_trans_handle *trans;
1186         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1187         struct btrfs_root *root = fs_info->tree_root;
1188
1189         trace_btrfs_sync_fs(fs_info, wait);
1190
1191         if (!wait) {
1192                 filemap_flush(fs_info->btree_inode->i_mapping);
1193                 return 0;
1194         }
1195
1196         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1197
1198         trans = btrfs_attach_transaction_barrier(root);
1199         if (IS_ERR(trans)) {
1200                 /* no transaction, don't bother */
1201                 if (PTR_ERR(trans) == -ENOENT) {
1202                         /*
1203                          * Exit unless we have some pending changes
1204                          * that need to go through commit
1205                          */
1206                         if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
1207                                       &fs_info->flags))
1208                                 return 0;
1209                         /*
1210                          * A non-blocking test if the fs is frozen. We must not
1211                          * start a new transaction here otherwise a deadlock
1212                          * happens. The pending operations are delayed to the
1213                          * next commit after thawing.
1214                          */
1215                         if (sb_start_write_trylock(sb))
1216                                 sb_end_write(sb);
1217                         else
1218                                 return 0;
1219                         trans = btrfs_start_transaction(root, 0);
1220                 }
1221                 if (IS_ERR(trans))
1222                         return PTR_ERR(trans);
1223         }
1224         return btrfs_commit_transaction(trans);
1225 }
1226
1227 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1228 {
1229         seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1230         *printed = true;
1231 }
1232
1233 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1234 {
1235         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1236         const char *compress_type;
1237         const char *subvol_name;
1238         bool printed = false;
1239
1240         if (btrfs_test_opt(info, DEGRADED))
1241                 seq_puts(seq, ",degraded");
1242         if (btrfs_test_opt(info, NODATASUM))
1243                 seq_puts(seq, ",nodatasum");
1244         if (btrfs_test_opt(info, NODATACOW))
1245                 seq_puts(seq, ",nodatacow");
1246         if (btrfs_test_opt(info, NOBARRIER))
1247                 seq_puts(seq, ",nobarrier");
1248         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1249                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1250         if (info->thread_pool_size !=  min_t(unsigned long,
1251                                              num_online_cpus() + 2, 8))
1252                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1253         if (btrfs_test_opt(info, COMPRESS)) {
1254                 compress_type = btrfs_compress_type2str(info->compress_type);
1255                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1256                         seq_printf(seq, ",compress-force=%s", compress_type);
1257                 else
1258                         seq_printf(seq, ",compress=%s", compress_type);
1259                 if (info->compress_level)
1260                         seq_printf(seq, ":%d", info->compress_level);
1261         }
1262         if (btrfs_test_opt(info, NOSSD))
1263                 seq_puts(seq, ",nossd");
1264         if (btrfs_test_opt(info, SSD_SPREAD))
1265                 seq_puts(seq, ",ssd_spread");
1266         else if (btrfs_test_opt(info, SSD))
1267                 seq_puts(seq, ",ssd");
1268         if (btrfs_test_opt(info, NOTREELOG))
1269                 seq_puts(seq, ",notreelog");
1270         if (btrfs_test_opt(info, NOLOGREPLAY))
1271                 print_rescue_option(seq, "nologreplay", &printed);
1272         if (btrfs_test_opt(info, USEBACKUPROOT))
1273                 print_rescue_option(seq, "usebackuproot", &printed);
1274         if (btrfs_test_opt(info, IGNOREBADROOTS))
1275                 print_rescue_option(seq, "ignorebadroots", &printed);
1276         if (btrfs_test_opt(info, IGNOREDATACSUMS))
1277                 print_rescue_option(seq, "ignoredatacsums", &printed);
1278         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1279                 seq_puts(seq, ",flushoncommit");
1280         if (btrfs_test_opt(info, DISCARD_SYNC))
1281                 seq_puts(seq, ",discard");
1282         if (btrfs_test_opt(info, DISCARD_ASYNC))
1283                 seq_puts(seq, ",discard=async");
1284         if (!(info->sb->s_flags & SB_POSIXACL))
1285                 seq_puts(seq, ",noacl");
1286         if (btrfs_free_space_cache_v1_active(info))
1287                 seq_puts(seq, ",space_cache");
1288         else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1289                 seq_puts(seq, ",space_cache=v2");
1290         else
1291                 seq_puts(seq, ",nospace_cache");
1292         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1293                 seq_puts(seq, ",rescan_uuid_tree");
1294         if (btrfs_test_opt(info, CLEAR_CACHE))
1295                 seq_puts(seq, ",clear_cache");
1296         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1297                 seq_puts(seq, ",user_subvol_rm_allowed");
1298         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1299                 seq_puts(seq, ",enospc_debug");
1300         if (btrfs_test_opt(info, AUTO_DEFRAG))
1301                 seq_puts(seq, ",autodefrag");
1302         if (btrfs_test_opt(info, SKIP_BALANCE))
1303                 seq_puts(seq, ",skip_balance");
1304 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1305         if (btrfs_test_opt(info, CHECK_INTEGRITY_DATA))
1306                 seq_puts(seq, ",check_int_data");
1307         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1308                 seq_puts(seq, ",check_int");
1309         if (info->check_integrity_print_mask)
1310                 seq_printf(seq, ",check_int_print_mask=%d",
1311                                 info->check_integrity_print_mask);
1312 #endif
1313         if (info->metadata_ratio)
1314                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1315         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1316                 seq_puts(seq, ",fatal_errors=panic");
1317         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1318                 seq_printf(seq, ",commit=%u", info->commit_interval);
1319 #ifdef CONFIG_BTRFS_DEBUG
1320         if (btrfs_test_opt(info, FRAGMENT_DATA))
1321                 seq_puts(seq, ",fragment=data");
1322         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1323                 seq_puts(seq, ",fragment=metadata");
1324 #endif
1325         if (btrfs_test_opt(info, REF_VERIFY))
1326                 seq_puts(seq, ",ref_verify");
1327         seq_printf(seq, ",subvolid=%llu",
1328                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1329         subvol_name = btrfs_get_subvol_name_from_objectid(info,
1330                         BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1331         if (!IS_ERR(subvol_name)) {
1332                 seq_puts(seq, ",subvol=");
1333                 seq_escape(seq, subvol_name, " \t\n\\");
1334                 kfree(subvol_name);
1335         }
1336         return 0;
1337 }
1338
1339 static int btrfs_test_super(struct super_block *s, void *data)
1340 {
1341         struct btrfs_fs_info *p = data;
1342         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1343
1344         return fs_info->fs_devices == p->fs_devices;
1345 }
1346
1347 static int btrfs_set_super(struct super_block *s, void *data)
1348 {
1349         int err = set_anon_super(s, data);
1350         if (!err)
1351                 s->s_fs_info = data;
1352         return err;
1353 }
1354
1355 /*
1356  * subvolumes are identified by ino 256
1357  */
1358 static inline int is_subvolume_inode(struct inode *inode)
1359 {
1360         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1361                 return 1;
1362         return 0;
1363 }
1364
1365 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1366                                    struct vfsmount *mnt)
1367 {
1368         struct dentry *root;
1369         int ret;
1370
1371         if (!subvol_name) {
1372                 if (!subvol_objectid) {
1373                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1374                                                           &subvol_objectid);
1375                         if (ret) {
1376                                 root = ERR_PTR(ret);
1377                                 goto out;
1378                         }
1379                 }
1380                 subvol_name = btrfs_get_subvol_name_from_objectid(
1381                                         btrfs_sb(mnt->mnt_sb), subvol_objectid);
1382                 if (IS_ERR(subvol_name)) {
1383                         root = ERR_CAST(subvol_name);
1384                         subvol_name = NULL;
1385                         goto out;
1386                 }
1387
1388         }
1389
1390         root = mount_subtree(mnt, subvol_name);
1391         /* mount_subtree() drops our reference on the vfsmount. */
1392         mnt = NULL;
1393
1394         if (!IS_ERR(root)) {
1395                 struct super_block *s = root->d_sb;
1396                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1397                 struct inode *root_inode = d_inode(root);
1398                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1399
1400                 ret = 0;
1401                 if (!is_subvolume_inode(root_inode)) {
1402                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1403                                subvol_name);
1404                         ret = -EINVAL;
1405                 }
1406                 if (subvol_objectid && root_objectid != subvol_objectid) {
1407                         /*
1408                          * This will also catch a race condition where a
1409                          * subvolume which was passed by ID is renamed and
1410                          * another subvolume is renamed over the old location.
1411                          */
1412                         btrfs_err(fs_info,
1413                                   "subvol '%s' does not match subvolid %llu",
1414                                   subvol_name, subvol_objectid);
1415                         ret = -EINVAL;
1416                 }
1417                 if (ret) {
1418                         dput(root);
1419                         root = ERR_PTR(ret);
1420                         deactivate_locked_super(s);
1421                 }
1422         }
1423
1424 out:
1425         mntput(mnt);
1426         kfree(subvol_name);
1427         return root;
1428 }
1429
1430 /*
1431  * Find a superblock for the given device / mount point.
1432  *
1433  * Note: This is based on mount_bdev from fs/super.c with a few additions
1434  *       for multiple device setup.  Make sure to keep it in sync.
1435  */
1436 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1437                 int flags, const char *device_name, void *data)
1438 {
1439         struct block_device *bdev = NULL;
1440         struct super_block *s;
1441         struct btrfs_device *device = NULL;
1442         struct btrfs_fs_devices *fs_devices = NULL;
1443         struct btrfs_fs_info *fs_info = NULL;
1444         void *new_sec_opts = NULL;
1445         fmode_t mode = FMODE_READ;
1446         int error = 0;
1447
1448         if (!(flags & SB_RDONLY))
1449                 mode |= FMODE_WRITE;
1450
1451         if (data) {
1452                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1453                 if (error)
1454                         return ERR_PTR(error);
1455         }
1456
1457         /*
1458          * Setup a dummy root and fs_info for test/set super.  This is because
1459          * we don't actually fill this stuff out until open_ctree, but we need
1460          * then open_ctree will properly initialize the file system specific
1461          * settings later.  btrfs_init_fs_info initializes the static elements
1462          * of the fs_info (locks and such) to make cleanup easier if we find a
1463          * superblock with our given fs_devices later on at sget() time.
1464          */
1465         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1466         if (!fs_info) {
1467                 error = -ENOMEM;
1468                 goto error_sec_opts;
1469         }
1470         btrfs_init_fs_info(fs_info);
1471
1472         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1473         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1474         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1475                 error = -ENOMEM;
1476                 goto error_fs_info;
1477         }
1478
1479         mutex_lock(&uuid_mutex);
1480         error = btrfs_parse_device_options(data, mode, fs_type);
1481         if (error) {
1482                 mutex_unlock(&uuid_mutex);
1483                 goto error_fs_info;
1484         }
1485
1486         device = btrfs_scan_one_device(device_name, mode, fs_type);
1487         if (IS_ERR(device)) {
1488                 mutex_unlock(&uuid_mutex);
1489                 error = PTR_ERR(device);
1490                 goto error_fs_info;
1491         }
1492
1493         fs_devices = device->fs_devices;
1494         fs_info->fs_devices = fs_devices;
1495
1496         error = btrfs_open_devices(fs_devices, mode, fs_type);
1497         mutex_unlock(&uuid_mutex);
1498         if (error)
1499                 goto error_fs_info;
1500
1501         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1502                 error = -EACCES;
1503                 goto error_close_devices;
1504         }
1505
1506         bdev = fs_devices->latest_dev->bdev;
1507         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1508                  fs_info);
1509         if (IS_ERR(s)) {
1510                 error = PTR_ERR(s);
1511                 goto error_close_devices;
1512         }
1513
1514         if (s->s_root) {
1515                 btrfs_close_devices(fs_devices);
1516                 btrfs_free_fs_info(fs_info);
1517                 if ((flags ^ s->s_flags) & SB_RDONLY)
1518                         error = -EBUSY;
1519         } else {
1520                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1521                 shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name,
1522                                         s->s_id);
1523                 btrfs_sb(s)->bdev_holder = fs_type;
1524                 error = btrfs_fill_super(s, fs_devices, data);
1525         }
1526         if (!error)
1527                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1528         security_free_mnt_opts(&new_sec_opts);
1529         if (error) {
1530                 deactivate_locked_super(s);
1531                 return ERR_PTR(error);
1532         }
1533
1534         return dget(s->s_root);
1535
1536 error_close_devices:
1537         btrfs_close_devices(fs_devices);
1538 error_fs_info:
1539         btrfs_free_fs_info(fs_info);
1540 error_sec_opts:
1541         security_free_mnt_opts(&new_sec_opts);
1542         return ERR_PTR(error);
1543 }
1544
1545 /*
1546  * Mount function which is called by VFS layer.
1547  *
1548  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1549  * which needs vfsmount* of device's root (/).  This means device's root has to
1550  * be mounted internally in any case.
1551  *
1552  * Operation flow:
1553  *   1. Parse subvol id related options for later use in mount_subvol().
1554  *
1555  *   2. Mount device's root (/) by calling vfs_kern_mount().
1556  *
1557  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1558  *      first place. In order to avoid calling btrfs_mount() again, we use
1559  *      different file_system_type which is not registered to VFS by
1560  *      register_filesystem() (btrfs_root_fs_type). As a result,
1561  *      btrfs_mount_root() is called. The return value will be used by
1562  *      mount_subtree() in mount_subvol().
1563  *
1564  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1565  *      "btrfs subvolume set-default", mount_subvol() is called always.
1566  */
1567 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1568                 const char *device_name, void *data)
1569 {
1570         struct vfsmount *mnt_root;
1571         struct dentry *root;
1572         char *subvol_name = NULL;
1573         u64 subvol_objectid = 0;
1574         int error = 0;
1575
1576         error = btrfs_parse_subvol_options(data, &subvol_name,
1577                                         &subvol_objectid);
1578         if (error) {
1579                 kfree(subvol_name);
1580                 return ERR_PTR(error);
1581         }
1582
1583         /* mount device's root (/) */
1584         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1585         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1586                 if (flags & SB_RDONLY) {
1587                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1588                                 flags & ~SB_RDONLY, device_name, data);
1589                 } else {
1590                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1591                                 flags | SB_RDONLY, device_name, data);
1592                         if (IS_ERR(mnt_root)) {
1593                                 root = ERR_CAST(mnt_root);
1594                                 kfree(subvol_name);
1595                                 goto out;
1596                         }
1597
1598                         down_write(&mnt_root->mnt_sb->s_umount);
1599                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1600                         up_write(&mnt_root->mnt_sb->s_umount);
1601                         if (error < 0) {
1602                                 root = ERR_PTR(error);
1603                                 mntput(mnt_root);
1604                                 kfree(subvol_name);
1605                                 goto out;
1606                         }
1607                 }
1608         }
1609         if (IS_ERR(mnt_root)) {
1610                 root = ERR_CAST(mnt_root);
1611                 kfree(subvol_name);
1612                 goto out;
1613         }
1614
1615         /* mount_subvol() will free subvol_name and mnt_root */
1616         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1617
1618 out:
1619         return root;
1620 }
1621
1622 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1623                                      u32 new_pool_size, u32 old_pool_size)
1624 {
1625         if (new_pool_size == old_pool_size)
1626                 return;
1627
1628         fs_info->thread_pool_size = new_pool_size;
1629
1630         btrfs_info(fs_info, "resize thread pool %d -> %d",
1631                old_pool_size, new_pool_size);
1632
1633         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1634         btrfs_workqueue_set_max(fs_info->hipri_workers, new_pool_size);
1635         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1636         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1637         workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1638         workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1639         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1640         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1641         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1642 }
1643
1644 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1645                                        unsigned long old_opts, int flags)
1646 {
1647         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1648             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1649              (flags & SB_RDONLY))) {
1650                 /* wait for any defraggers to finish */
1651                 wait_event(fs_info->transaction_wait,
1652                            (atomic_read(&fs_info->defrag_running) == 0));
1653                 if (flags & SB_RDONLY)
1654                         sync_filesystem(fs_info->sb);
1655         }
1656 }
1657
1658 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1659                                          unsigned long old_opts)
1660 {
1661         const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1662
1663         /*
1664          * We need to cleanup all defragable inodes if the autodefragment is
1665          * close or the filesystem is read only.
1666          */
1667         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1668             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1669                 btrfs_cleanup_defrag_inodes(fs_info);
1670         }
1671
1672         /* If we toggled discard async */
1673         if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1674             btrfs_test_opt(fs_info, DISCARD_ASYNC))
1675                 btrfs_discard_resume(fs_info);
1676         else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1677                  !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1678                 btrfs_discard_cleanup(fs_info);
1679
1680         /* If we toggled space cache */
1681         if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1682                 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1683 }
1684
1685 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1686 {
1687         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1688         unsigned old_flags = sb->s_flags;
1689         unsigned long old_opts = fs_info->mount_opt;
1690         unsigned long old_compress_type = fs_info->compress_type;
1691         u64 old_max_inline = fs_info->max_inline;
1692         u32 old_thread_pool_size = fs_info->thread_pool_size;
1693         u32 old_metadata_ratio = fs_info->metadata_ratio;
1694         int ret;
1695
1696         sync_filesystem(sb);
1697         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1698
1699         if (data) {
1700                 void *new_sec_opts = NULL;
1701
1702                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1703                 if (!ret)
1704                         ret = security_sb_remount(sb, new_sec_opts);
1705                 security_free_mnt_opts(&new_sec_opts);
1706                 if (ret)
1707                         goto restore;
1708         }
1709
1710         ret = btrfs_parse_options(fs_info, data, *flags);
1711         if (ret)
1712                 goto restore;
1713
1714         ret = btrfs_check_features(fs_info, !(*flags & SB_RDONLY));
1715         if (ret < 0)
1716                 goto restore;
1717
1718         btrfs_remount_begin(fs_info, old_opts, *flags);
1719         btrfs_resize_thread_pool(fs_info,
1720                 fs_info->thread_pool_size, old_thread_pool_size);
1721
1722         if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1723             (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1724             (!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
1725                 btrfs_warn(fs_info,
1726                 "remount supports changing free space tree only from ro to rw");
1727                 /* Make sure free space cache options match the state on disk */
1728                 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1729                         btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1730                         btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1731                 }
1732                 if (btrfs_free_space_cache_v1_active(fs_info)) {
1733                         btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1734                         btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1735                 }
1736         }
1737
1738         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1739                 goto out;
1740
1741         if (*flags & SB_RDONLY) {
1742                 /*
1743                  * this also happens on 'umount -rf' or on shutdown, when
1744                  * the filesystem is busy.
1745                  */
1746                 cancel_work_sync(&fs_info->async_reclaim_work);
1747                 cancel_work_sync(&fs_info->async_data_reclaim_work);
1748
1749                 btrfs_discard_cleanup(fs_info);
1750
1751                 /* wait for the uuid_scan task to finish */
1752                 down(&fs_info->uuid_tree_rescan_sem);
1753                 /* avoid complains from lockdep et al. */
1754                 up(&fs_info->uuid_tree_rescan_sem);
1755
1756                 btrfs_set_sb_rdonly(sb);
1757
1758                 /*
1759                  * Setting SB_RDONLY will put the cleaner thread to
1760                  * sleep at the next loop if it's already active.
1761                  * If it's already asleep, we'll leave unused block
1762                  * groups on disk until we're mounted read-write again
1763                  * unless we clean them up here.
1764                  */
1765                 btrfs_delete_unused_bgs(fs_info);
1766
1767                 /*
1768                  * The cleaner task could be already running before we set the
1769                  * flag BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock).
1770                  * We must make sure that after we finish the remount, i.e. after
1771                  * we call btrfs_commit_super(), the cleaner can no longer start
1772                  * a transaction - either because it was dropping a dead root,
1773                  * running delayed iputs or deleting an unused block group (the
1774                  * cleaner picked a block group from the list of unused block
1775                  * groups before we were able to in the previous call to
1776                  * btrfs_delete_unused_bgs()).
1777                  */
1778                 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING,
1779                             TASK_UNINTERRUPTIBLE);
1780
1781                 /*
1782                  * We've set the superblock to RO mode, so we might have made
1783                  * the cleaner task sleep without running all pending delayed
1784                  * iputs. Go through all the delayed iputs here, so that if an
1785                  * unmount happens without remounting RW we don't end up at
1786                  * finishing close_ctree() with a non-empty list of delayed
1787                  * iputs.
1788                  */
1789                 btrfs_run_delayed_iputs(fs_info);
1790
1791                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1792                 btrfs_scrub_cancel(fs_info);
1793                 btrfs_pause_balance(fs_info);
1794
1795                 /*
1796                  * Pause the qgroup rescan worker if it is running. We don't want
1797                  * it to be still running after we are in RO mode, as after that,
1798                  * by the time we unmount, it might have left a transaction open,
1799                  * so we would leak the transaction and/or crash.
1800                  */
1801                 btrfs_qgroup_wait_for_completion(fs_info, false);
1802
1803                 ret = btrfs_commit_super(fs_info);
1804                 if (ret)
1805                         goto restore;
1806         } else {
1807                 if (BTRFS_FS_ERROR(fs_info)) {
1808                         btrfs_err(fs_info,
1809                                 "Remounting read-write after error is not allowed");
1810                         ret = -EINVAL;
1811                         goto restore;
1812                 }
1813                 if (fs_info->fs_devices->rw_devices == 0) {
1814                         ret = -EACCES;
1815                         goto restore;
1816                 }
1817
1818                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1819                         btrfs_warn(fs_info,
1820                 "too many missing devices, writable remount is not allowed");
1821                         ret = -EACCES;
1822                         goto restore;
1823                 }
1824
1825                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1826                         btrfs_warn(fs_info,
1827                 "mount required to replay tree-log, cannot remount read-write");
1828                         ret = -EINVAL;
1829                         goto restore;
1830                 }
1831
1832                 /*
1833                  * NOTE: when remounting with a change that does writes, don't
1834                  * put it anywhere above this point, as we are not sure to be
1835                  * safe to write until we pass the above checks.
1836                  */
1837                 ret = btrfs_start_pre_rw_mount(fs_info);
1838                 if (ret)
1839                         goto restore;
1840
1841                 btrfs_clear_sb_rdonly(sb);
1842
1843                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1844
1845                 /*
1846                  * If we've gone from readonly -> read/write, we need to get
1847                  * our sync/async discard lists in the right state.
1848                  */
1849                 btrfs_discard_resume(fs_info);
1850         }
1851 out:
1852         /*
1853          * We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
1854          * since the absence of the flag means it can be toggled off by remount.
1855          */
1856         *flags |= SB_I_VERSION;
1857
1858         wake_up_process(fs_info->transaction_kthread);
1859         btrfs_remount_cleanup(fs_info, old_opts);
1860         btrfs_clear_oneshot_options(fs_info);
1861         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1862
1863         return 0;
1864
1865 restore:
1866         /* We've hit an error - don't reset SB_RDONLY */
1867         if (sb_rdonly(sb))
1868                 old_flags |= SB_RDONLY;
1869         if (!(old_flags & SB_RDONLY))
1870                 clear_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
1871         sb->s_flags = old_flags;
1872         fs_info->mount_opt = old_opts;
1873         fs_info->compress_type = old_compress_type;
1874         fs_info->max_inline = old_max_inline;
1875         btrfs_resize_thread_pool(fs_info,
1876                 old_thread_pool_size, fs_info->thread_pool_size);
1877         fs_info->metadata_ratio = old_metadata_ratio;
1878         btrfs_remount_cleanup(fs_info, old_opts);
1879         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1880
1881         return ret;
1882 }
1883
1884 /* Used to sort the devices by max_avail(descending sort) */
1885 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1886 {
1887         const struct btrfs_device_info *dev_info1 = a;
1888         const struct btrfs_device_info *dev_info2 = b;
1889
1890         if (dev_info1->max_avail > dev_info2->max_avail)
1891                 return -1;
1892         else if (dev_info1->max_avail < dev_info2->max_avail)
1893                 return 1;
1894         return 0;
1895 }
1896
1897 /*
1898  * sort the devices by max_avail, in which max free extent size of each device
1899  * is stored.(Descending Sort)
1900  */
1901 static inline void btrfs_descending_sort_devices(
1902                                         struct btrfs_device_info *devices,
1903                                         size_t nr_devices)
1904 {
1905         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1906              btrfs_cmp_device_free_bytes, NULL);
1907 }
1908
1909 /*
1910  * The helper to calc the free space on the devices that can be used to store
1911  * file data.
1912  */
1913 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1914                                               u64 *free_bytes)
1915 {
1916         struct btrfs_device_info *devices_info;
1917         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1918         struct btrfs_device *device;
1919         u64 type;
1920         u64 avail_space;
1921         u64 min_stripe_size;
1922         int num_stripes = 1;
1923         int i = 0, nr_devices;
1924         const struct btrfs_raid_attr *rattr;
1925
1926         /*
1927          * We aren't under the device list lock, so this is racy-ish, but good
1928          * enough for our purposes.
1929          */
1930         nr_devices = fs_info->fs_devices->open_devices;
1931         if (!nr_devices) {
1932                 smp_mb();
1933                 nr_devices = fs_info->fs_devices->open_devices;
1934                 ASSERT(nr_devices);
1935                 if (!nr_devices) {
1936                         *free_bytes = 0;
1937                         return 0;
1938                 }
1939         }
1940
1941         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1942                                GFP_KERNEL);
1943         if (!devices_info)
1944                 return -ENOMEM;
1945
1946         /* calc min stripe number for data space allocation */
1947         type = btrfs_data_alloc_profile(fs_info);
1948         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1949
1950         if (type & BTRFS_BLOCK_GROUP_RAID0)
1951                 num_stripes = nr_devices;
1952         else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1953                 num_stripes = rattr->ncopies;
1954         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1955                 num_stripes = 4;
1956
1957         /* Adjust for more than 1 stripe per device */
1958         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1959
1960         rcu_read_lock();
1961         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1962                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1963                                                 &device->dev_state) ||
1964                     !device->bdev ||
1965                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1966                         continue;
1967
1968                 if (i >= nr_devices)
1969                         break;
1970
1971                 avail_space = device->total_bytes - device->bytes_used;
1972
1973                 /* align with stripe_len */
1974                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1975
1976                 /*
1977                  * Ensure we have at least min_stripe_size on top of the
1978                  * reserved space on the device.
1979                  */
1980                 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1981                         continue;
1982
1983                 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1984
1985                 devices_info[i].dev = device;
1986                 devices_info[i].max_avail = avail_space;
1987
1988                 i++;
1989         }
1990         rcu_read_unlock();
1991
1992         nr_devices = i;
1993
1994         btrfs_descending_sort_devices(devices_info, nr_devices);
1995
1996         i = nr_devices - 1;
1997         avail_space = 0;
1998         while (nr_devices >= rattr->devs_min) {
1999                 num_stripes = min(num_stripes, nr_devices);
2000
2001                 if (devices_info[i].max_avail >= min_stripe_size) {
2002                         int j;
2003                         u64 alloc_size;
2004
2005                         avail_space += devices_info[i].max_avail * num_stripes;
2006                         alloc_size = devices_info[i].max_avail;
2007                         for (j = i + 1 - num_stripes; j <= i; j++)
2008                                 devices_info[j].max_avail -= alloc_size;
2009                 }
2010                 i--;
2011                 nr_devices--;
2012         }
2013
2014         kfree(devices_info);
2015         *free_bytes = avail_space;
2016         return 0;
2017 }
2018
2019 /*
2020  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2021  *
2022  * If there's a redundant raid level at DATA block groups, use the respective
2023  * multiplier to scale the sizes.
2024  *
2025  * Unused device space usage is based on simulating the chunk allocator
2026  * algorithm that respects the device sizes and order of allocations.  This is
2027  * a close approximation of the actual use but there are other factors that may
2028  * change the result (like a new metadata chunk).
2029  *
2030  * If metadata is exhausted, f_bavail will be 0.
2031  */
2032 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2033 {
2034         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2035         struct btrfs_super_block *disk_super = fs_info->super_copy;
2036         struct btrfs_space_info *found;
2037         u64 total_used = 0;
2038         u64 total_free_data = 0;
2039         u64 total_free_meta = 0;
2040         u32 bits = fs_info->sectorsize_bits;
2041         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2042         unsigned factor = 1;
2043         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2044         int ret;
2045         u64 thresh = 0;
2046         int mixed = 0;
2047
2048         list_for_each_entry(found, &fs_info->space_info, list) {
2049                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2050                         int i;
2051
2052                         total_free_data += found->disk_total - found->disk_used;
2053                         total_free_data -=
2054                                 btrfs_account_ro_block_groups_free_space(found);
2055
2056                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2057                                 if (!list_empty(&found->block_groups[i]))
2058                                         factor = btrfs_bg_type_to_factor(
2059                                                 btrfs_raid_array[i].bg_flag);
2060                         }
2061                 }
2062
2063                 /*
2064                  * Metadata in mixed block group profiles are accounted in data
2065                  */
2066                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2067                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2068                                 mixed = 1;
2069                         else
2070                                 total_free_meta += found->disk_total -
2071                                         found->disk_used;
2072                 }
2073
2074                 total_used += found->disk_used;
2075         }
2076
2077         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2078         buf->f_blocks >>= bits;
2079         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2080
2081         /* Account global block reserve as used, it's in logical size already */
2082         spin_lock(&block_rsv->lock);
2083         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2084         if (buf->f_bfree >= block_rsv->size >> bits)
2085                 buf->f_bfree -= block_rsv->size >> bits;
2086         else
2087                 buf->f_bfree = 0;
2088         spin_unlock(&block_rsv->lock);
2089
2090         buf->f_bavail = div_u64(total_free_data, factor);
2091         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2092         if (ret)
2093                 return ret;
2094         buf->f_bavail += div_u64(total_free_data, factor);
2095         buf->f_bavail = buf->f_bavail >> bits;
2096
2097         /*
2098          * We calculate the remaining metadata space minus global reserve. If
2099          * this is (supposedly) smaller than zero, there's no space. But this
2100          * does not hold in practice, the exhausted state happens where's still
2101          * some positive delta. So we apply some guesswork and compare the
2102          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2103          *
2104          * We probably cannot calculate the exact threshold value because this
2105          * depends on the internal reservations requested by various
2106          * operations, so some operations that consume a few metadata will
2107          * succeed even if the Avail is zero. But this is better than the other
2108          * way around.
2109          */
2110         thresh = SZ_4M;
2111
2112         /*
2113          * We only want to claim there's no available space if we can no longer
2114          * allocate chunks for our metadata profile and our global reserve will
2115          * not fit in the free metadata space.  If we aren't ->full then we
2116          * still can allocate chunks and thus are fine using the currently
2117          * calculated f_bavail.
2118          */
2119         if (!mixed && block_rsv->space_info->full &&
2120             total_free_meta - thresh < block_rsv->size)
2121                 buf->f_bavail = 0;
2122
2123         buf->f_type = BTRFS_SUPER_MAGIC;
2124         buf->f_bsize = dentry->d_sb->s_blocksize;
2125         buf->f_namelen = BTRFS_NAME_LEN;
2126
2127         /* We treat it as constant endianness (it doesn't matter _which_)
2128            because we want the fsid to come out the same whether mounted
2129            on a big-endian or little-endian host */
2130         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2131         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2132         /* Mask in the root object ID too, to disambiguate subvols */
2133         buf->f_fsid.val[0] ^=
2134                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2135         buf->f_fsid.val[1] ^=
2136                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2137
2138         return 0;
2139 }
2140
2141 static void btrfs_kill_super(struct super_block *sb)
2142 {
2143         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2144         kill_anon_super(sb);
2145         btrfs_free_fs_info(fs_info);
2146 }
2147
2148 static struct file_system_type btrfs_fs_type = {
2149         .owner          = THIS_MODULE,
2150         .name           = "btrfs",
2151         .mount          = btrfs_mount,
2152         .kill_sb        = btrfs_kill_super,
2153         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2154 };
2155
2156 static struct file_system_type btrfs_root_fs_type = {
2157         .owner          = THIS_MODULE,
2158         .name           = "btrfs",
2159         .mount          = btrfs_mount_root,
2160         .kill_sb        = btrfs_kill_super,
2161         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2162 };
2163
2164 MODULE_ALIAS_FS("btrfs");
2165
2166 static int btrfs_control_open(struct inode *inode, struct file *file)
2167 {
2168         /*
2169          * The control file's private_data is used to hold the
2170          * transaction when it is started and is used to keep
2171          * track of whether a transaction is already in progress.
2172          */
2173         file->private_data = NULL;
2174         return 0;
2175 }
2176
2177 /*
2178  * Used by /dev/btrfs-control for devices ioctls.
2179  */
2180 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2181                                 unsigned long arg)
2182 {
2183         struct btrfs_ioctl_vol_args *vol;
2184         struct btrfs_device *device = NULL;
2185         dev_t devt = 0;
2186         int ret = -ENOTTY;
2187
2188         if (!capable(CAP_SYS_ADMIN))
2189                 return -EPERM;
2190
2191         vol = memdup_user((void __user *)arg, sizeof(*vol));
2192         if (IS_ERR(vol))
2193                 return PTR_ERR(vol);
2194         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2195
2196         switch (cmd) {
2197         case BTRFS_IOC_SCAN_DEV:
2198                 mutex_lock(&uuid_mutex);
2199                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2200                                                &btrfs_root_fs_type);
2201                 ret = PTR_ERR_OR_ZERO(device);
2202                 mutex_unlock(&uuid_mutex);
2203                 break;
2204         case BTRFS_IOC_FORGET_DEV:
2205                 if (vol->name[0] != 0) {
2206                         ret = lookup_bdev(vol->name, &devt);
2207                         if (ret)
2208                                 break;
2209                 }
2210                 ret = btrfs_forget_devices(devt);
2211                 break;
2212         case BTRFS_IOC_DEVICES_READY:
2213                 mutex_lock(&uuid_mutex);
2214                 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2215                                                &btrfs_root_fs_type);
2216                 if (IS_ERR(device)) {
2217                         mutex_unlock(&uuid_mutex);
2218                         ret = PTR_ERR(device);
2219                         break;
2220                 }
2221                 ret = !(device->fs_devices->num_devices ==
2222                         device->fs_devices->total_devices);
2223                 mutex_unlock(&uuid_mutex);
2224                 break;
2225         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2226                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2227                 break;
2228         }
2229
2230         kfree(vol);
2231         return ret;
2232 }
2233
2234 static int btrfs_freeze(struct super_block *sb)
2235 {
2236         struct btrfs_trans_handle *trans;
2237         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2238         struct btrfs_root *root = fs_info->tree_root;
2239
2240         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2241         /*
2242          * We don't need a barrier here, we'll wait for any transaction that
2243          * could be in progress on other threads (and do delayed iputs that
2244          * we want to avoid on a frozen filesystem), or do the commit
2245          * ourselves.
2246          */
2247         trans = btrfs_attach_transaction_barrier(root);
2248         if (IS_ERR(trans)) {
2249                 /* no transaction, don't bother */
2250                 if (PTR_ERR(trans) == -ENOENT)
2251                         return 0;
2252                 return PTR_ERR(trans);
2253         }
2254         return btrfs_commit_transaction(trans);
2255 }
2256
2257 static int check_dev_super(struct btrfs_device *dev)
2258 {
2259         struct btrfs_fs_info *fs_info = dev->fs_info;
2260         struct btrfs_super_block *sb;
2261         u16 csum_type;
2262         int ret = 0;
2263
2264         /* This should be called with fs still frozen. */
2265         ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2266
2267         /* Missing dev, no need to check. */
2268         if (!dev->bdev)
2269                 return 0;
2270
2271         /* Only need to check the primary super block. */
2272         sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2273         if (IS_ERR(sb))
2274                 return PTR_ERR(sb);
2275
2276         /* Verify the checksum. */
2277         csum_type = btrfs_super_csum_type(sb);
2278         if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2279                 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2280                           csum_type, btrfs_super_csum_type(fs_info->super_copy));
2281                 ret = -EUCLEAN;
2282                 goto out;
2283         }
2284
2285         if (btrfs_check_super_csum(fs_info, sb)) {
2286                 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2287                 ret = -EUCLEAN;
2288                 goto out;
2289         }
2290
2291         /* Btrfs_validate_super() includes fsid check against super->fsid. */
2292         ret = btrfs_validate_super(fs_info, sb, 0);
2293         if (ret < 0)
2294                 goto out;
2295
2296         if (btrfs_super_generation(sb) != fs_info->last_trans_committed) {
2297                 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2298                         btrfs_super_generation(sb),
2299                         fs_info->last_trans_committed);
2300                 ret = -EUCLEAN;
2301                 goto out;
2302         }
2303 out:
2304         btrfs_release_disk_super(sb);
2305         return ret;
2306 }
2307
2308 static int btrfs_unfreeze(struct super_block *sb)
2309 {
2310         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2311         struct btrfs_device *device;
2312         int ret = 0;
2313
2314         /*
2315          * Make sure the fs is not changed by accident (like hibernation then
2316          * modified by other OS).
2317          * If we found anything wrong, we mark the fs error immediately.
2318          *
2319          * And since the fs is frozen, no one can modify the fs yet, thus
2320          * we don't need to hold device_list_mutex.
2321          */
2322         list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2323                 ret = check_dev_super(device);
2324                 if (ret < 0) {
2325                         btrfs_handle_fs_error(fs_info, ret,
2326                                 "super block on devid %llu got modified unexpectedly",
2327                                 device->devid);
2328                         break;
2329                 }
2330         }
2331         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2332
2333         /*
2334          * We still return 0, to allow VFS layer to unfreeze the fs even the
2335          * above checks failed. Since the fs is either fine or read-only, we're
2336          * safe to continue, without causing further damage.
2337          */
2338         return 0;
2339 }
2340
2341 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2342 {
2343         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2344
2345         /*
2346          * There should be always a valid pointer in latest_dev, it may be stale
2347          * for a short moment in case it's being deleted but still valid until
2348          * the end of RCU grace period.
2349          */
2350         rcu_read_lock();
2351         seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2352         rcu_read_unlock();
2353
2354         return 0;
2355 }
2356
2357 static const struct super_operations btrfs_super_ops = {
2358         .drop_inode     = btrfs_drop_inode,
2359         .evict_inode    = btrfs_evict_inode,
2360         .put_super      = btrfs_put_super,
2361         .sync_fs        = btrfs_sync_fs,
2362         .show_options   = btrfs_show_options,
2363         .show_devname   = btrfs_show_devname,
2364         .alloc_inode    = btrfs_alloc_inode,
2365         .destroy_inode  = btrfs_destroy_inode,
2366         .free_inode     = btrfs_free_inode,
2367         .statfs         = btrfs_statfs,
2368         .remount_fs     = btrfs_remount,
2369         .freeze_fs      = btrfs_freeze,
2370         .unfreeze_fs    = btrfs_unfreeze,
2371 };
2372
2373 static const struct file_operations btrfs_ctl_fops = {
2374         .open = btrfs_control_open,
2375         .unlocked_ioctl  = btrfs_control_ioctl,
2376         .compat_ioctl = compat_ptr_ioctl,
2377         .owner   = THIS_MODULE,
2378         .llseek = noop_llseek,
2379 };
2380
2381 static struct miscdevice btrfs_misc = {
2382         .minor          = BTRFS_MINOR,
2383         .name           = "btrfs-control",
2384         .fops           = &btrfs_ctl_fops
2385 };
2386
2387 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2388 MODULE_ALIAS("devname:btrfs-control");
2389
2390 static int __init btrfs_interface_init(void)
2391 {
2392         return misc_register(&btrfs_misc);
2393 }
2394
2395 static __cold void btrfs_interface_exit(void)
2396 {
2397         misc_deregister(&btrfs_misc);
2398 }
2399
2400 static int __init btrfs_print_mod_info(void)
2401 {
2402         static const char options[] = ""
2403 #ifdef CONFIG_BTRFS_DEBUG
2404                         ", debug=on"
2405 #endif
2406 #ifdef CONFIG_BTRFS_ASSERT
2407                         ", assert=on"
2408 #endif
2409 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2410                         ", integrity-checker=on"
2411 #endif
2412 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2413                         ", ref-verify=on"
2414 #endif
2415 #ifdef CONFIG_BLK_DEV_ZONED
2416                         ", zoned=yes"
2417 #else
2418                         ", zoned=no"
2419 #endif
2420 #ifdef CONFIG_FS_VERITY
2421                         ", fsverity=yes"
2422 #else
2423                         ", fsverity=no"
2424 #endif
2425                         ;
2426         pr_info("Btrfs loaded%s\n", options);
2427         return 0;
2428 }
2429
2430 static int register_btrfs(void)
2431 {
2432         return register_filesystem(&btrfs_fs_type);
2433 }
2434
2435 static void unregister_btrfs(void)
2436 {
2437         unregister_filesystem(&btrfs_fs_type);
2438 }
2439
2440 /* Helper structure for long init/exit functions. */
2441 struct init_sequence {
2442         int (*init_func)(void);
2443         /* Can be NULL if the init_func doesn't need cleanup. */
2444         void (*exit_func)(void);
2445 };
2446
2447 static const struct init_sequence mod_init_seq[] = {
2448         {
2449                 .init_func = btrfs_props_init,
2450                 .exit_func = NULL,
2451         }, {
2452                 .init_func = btrfs_init_sysfs,
2453                 .exit_func = btrfs_exit_sysfs,
2454         }, {
2455                 .init_func = btrfs_init_compress,
2456                 .exit_func = btrfs_exit_compress,
2457         }, {
2458                 .init_func = btrfs_init_cachep,
2459                 .exit_func = btrfs_destroy_cachep,
2460         }, {
2461                 .init_func = btrfs_transaction_init,
2462                 .exit_func = btrfs_transaction_exit,
2463         }, {
2464                 .init_func = btrfs_ctree_init,
2465                 .exit_func = btrfs_ctree_exit,
2466         }, {
2467                 .init_func = btrfs_free_space_init,
2468                 .exit_func = btrfs_free_space_exit,
2469         }, {
2470                 .init_func = extent_state_init_cachep,
2471                 .exit_func = extent_state_free_cachep,
2472         }, {
2473                 .init_func = extent_buffer_init_cachep,
2474                 .exit_func = extent_buffer_free_cachep,
2475         }, {
2476                 .init_func = btrfs_bioset_init,
2477                 .exit_func = btrfs_bioset_exit,
2478         }, {
2479                 .init_func = extent_map_init,
2480                 .exit_func = extent_map_exit,
2481         }, {
2482                 .init_func = ordered_data_init,
2483                 .exit_func = ordered_data_exit,
2484         }, {
2485                 .init_func = btrfs_delayed_inode_init,
2486                 .exit_func = btrfs_delayed_inode_exit,
2487         }, {
2488                 .init_func = btrfs_auto_defrag_init,
2489                 .exit_func = btrfs_auto_defrag_exit,
2490         }, {
2491                 .init_func = btrfs_delayed_ref_init,
2492                 .exit_func = btrfs_delayed_ref_exit,
2493         }, {
2494                 .init_func = btrfs_prelim_ref_init,
2495                 .exit_func = btrfs_prelim_ref_exit,
2496         }, {
2497                 .init_func = btrfs_interface_init,
2498                 .exit_func = btrfs_interface_exit,
2499         }, {
2500                 .init_func = btrfs_print_mod_info,
2501                 .exit_func = NULL,
2502         }, {
2503                 .init_func = btrfs_run_sanity_tests,
2504                 .exit_func = NULL,
2505         }, {
2506                 .init_func = register_btrfs,
2507                 .exit_func = unregister_btrfs,
2508         }
2509 };
2510
2511 static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2512
2513 static __always_inline void btrfs_exit_btrfs_fs(void)
2514 {
2515         int i;
2516
2517         for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2518                 if (!mod_init_result[i])
2519                         continue;
2520                 if (mod_init_seq[i].exit_func)
2521                         mod_init_seq[i].exit_func();
2522                 mod_init_result[i] = false;
2523         }
2524 }
2525
2526 static void __exit exit_btrfs_fs(void)
2527 {
2528         btrfs_exit_btrfs_fs();
2529         btrfs_cleanup_fs_uuids();
2530 }
2531
2532 static int __init init_btrfs_fs(void)
2533 {
2534         int ret;
2535         int i;
2536
2537         for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2538                 ASSERT(!mod_init_result[i]);
2539                 ret = mod_init_seq[i].init_func();
2540                 if (ret < 0) {
2541                         btrfs_exit_btrfs_fs();
2542                         return ret;
2543                 }
2544                 mod_init_result[i] = true;
2545         }
2546         return 0;
2547 }
2548
2549 late_initcall(init_btrfs_fs);
2550 module_exit(exit_btrfs_fs)
2551
2552 MODULE_LICENSE("GPL");
2553 MODULE_SOFTDEP("pre: crc32c");
2554 MODULE_SOFTDEP("pre: xxhash64");
2555 MODULE_SOFTDEP("pre: sha256");
2556 MODULE_SOFTDEP("pre: blake2b-256");