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         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
  83
  84         btrfs_info(fs_info, "last unmount of filesystem %pU", fs_info->fs_devices->fsid);
  85         close_ctree(fs_info);
  86 }
  87
  88 enum {
  89         Opt_acl, Opt_noacl,
  90         Opt_clear_cache,
  91         Opt_commit_interval,
  92         Opt_compress,
  93         Opt_compress_force,
  94         Opt_compress_force_type,
  95         Opt_compress_type,
  96         Opt_degraded,
  97         Opt_device,
  98         Opt_fatal_errors,
  99         Opt_flushoncommit, Opt_noflushoncommit,
 100         Opt_max_inline,
 101         Opt_barrier, Opt_nobarrier,
 102         Opt_datacow, Opt_nodatacow,
 103         Opt_datasum, Opt_nodatasum,
 104         Opt_defrag, Opt_nodefrag,
 105         Opt_discard, Opt_nodiscard,
 106         Opt_discard_mode,
 107         Opt_norecovery,
 108         Opt_ratio,
 109         Opt_rescan_uuid_tree,
 110         Opt_skip_balance,
 111         Opt_space_cache, Opt_no_space_cache,
 112         Opt_space_cache_version,
 113         Opt_ssd, Opt_nossd,
 114         Opt_ssd_spread, Opt_nossd_spread,
 115         Opt_subvol,
 116         Opt_subvol_empty,
 117         Opt_subvolid,
 118         Opt_thread_pool,
 119         Opt_treelog, Opt_notreelog,
 120         Opt_user_subvol_rm_allowed,
 121
 122         /* Rescue options */
 123         Opt_rescue,
 124         Opt_usebackuproot,
 125         Opt_nologreplay,
 126         Opt_ignorebadroots,
 127         Opt_ignoredatacsums,
 128         Opt_rescue_all,
 129
 130         /* Deprecated options */
 131         Opt_recovery,
 132         Opt_inode_cache, Opt_noinode_cache,
 133
 134         /* Debugging options */
 135         Opt_check_integrity,
 136         Opt_check_integrity_including_extent_data,
 137         Opt_check_integrity_print_mask,
 138         Opt_enospc_debug, Opt_noenospc_debug,
 139 #ifdef CONFIG_BTRFS_DEBUG
 140         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 141 #endif
 142 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 143         Opt_ref_verify,
 144 #endif
 145         Opt_err,
 146 };
 147
 148 static const match_table_t tokens = {
 149         {Opt_acl, "acl"},
 150         {Opt_noacl, "noacl"},
 151         {Opt_clear_cache, "clear_cache"},
 152         {Opt_commit_interval, "commit=%u"},
 153         {Opt_compress, "compress"},
 154         {Opt_compress_type, "compress=%s"},
 155         {Opt_compress_force, "compress-force"},
 156         {Opt_compress_force_type, "compress-force=%s"},
 157         {Opt_degraded, "degraded"},
 158         {Opt_device, "device=%s"},
 159         {Opt_fatal_errors, "fatal_errors=%s"},
 160         {Opt_flushoncommit, "flushoncommit"},
 161         {Opt_noflushoncommit, "noflushoncommit"},
 162         {Opt_inode_cache, "inode_cache"},
 163         {Opt_noinode_cache, "noinode_cache"},
 164         {Opt_max_inline, "max_inline=%s"},
 165         {Opt_barrier, "barrier"},
 166         {Opt_nobarrier, "nobarrier"},
 167         {Opt_datacow, "datacow"},
 168         {Opt_nodatacow, "nodatacow"},
 169         {Opt_datasum, "datasum"},
 170         {Opt_nodatasum, "nodatasum"},
 171         {Opt_defrag, "autodefrag"},
 172         {Opt_nodefrag, "noautodefrag"},
 173         {Opt_discard, "discard"},
 174         {Opt_discard_mode, "discard=%s"},
 175         {Opt_nodiscard, "nodiscard"},
 176         {Opt_norecovery, "norecovery"},
 177         {Opt_ratio, "metadata_ratio=%u"},
 178         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 179         {Opt_skip_balance, "skip_balance"},
 180         {Opt_space_cache, "space_cache"},
 181         {Opt_no_space_cache, "nospace_cache"},
 182         {Opt_space_cache_version, "space_cache=%s"},
 183         {Opt_ssd, "ssd"},
 184         {Opt_nossd, "nossd"},
 185         {Opt_ssd_spread, "ssd_spread"},
 186         {Opt_nossd_spread, "nossd_spread"},
 187         {Opt_subvol, "subvol=%s"},
 188         {Opt_subvol_empty, "subvol="},
 189         {Opt_subvolid, "subvolid=%s"},
 190         {Opt_thread_pool, "thread_pool=%u"},
 191         {Opt_treelog, "treelog"},
 192         {Opt_notreelog, "notreelog"},
 193         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 194
 195         /* Rescue options */
 196         {Opt_rescue, "rescue=%s"},
 197         /* Deprecated, with alias rescue=nologreplay */
 198         {Opt_nologreplay, "nologreplay"},
 199         /* Deprecated, with alias rescue=usebackuproot */
 200         {Opt_usebackuproot, "usebackuproot"},
 201
 202         /* Deprecated options */
 203         {Opt_recovery, "recovery"},
 204
 205         /* Debugging options */
 206         {Opt_check_integrity, "check_int"},
 207         {Opt_check_integrity_including_extent_data, "check_int_data"},
 208         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
 209         {Opt_enospc_debug, "enospc_debug"},
 210         {Opt_noenospc_debug, "noenospc_debug"},
 211 #ifdef CONFIG_BTRFS_DEBUG
 212         {Opt_fragment_data, "fragment=data"},
 213         {Opt_fragment_metadata, "fragment=metadata"},
 214         {Opt_fragment_all, "fragment=all"},
 215 #endif
 216 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 217         {Opt_ref_verify, "ref_verify"},
 218 #endif
 219         {Opt_err, NULL},
 220 };
 221
 222 static const match_table_t rescue_tokens = {
 223         {Opt_usebackuproot, "usebackuproot"},
 224         {Opt_nologreplay, "nologreplay"},
 225         {Opt_ignorebadroots, "ignorebadroots"},
 226         {Opt_ignorebadroots, "ibadroots"},
 227         {Opt_ignoredatacsums, "ignoredatacsums"},
 228         {Opt_ignoredatacsums, "idatacsums"},
 229         {Opt_rescue_all, "all"},
 230         {Opt_err, NULL},
 231 };
 232
 233 static bool check_ro_option(struct btrfs_fs_info *fs_info, unsigned long opt,
 234                             const char *opt_name)
 235 {
 236         if (fs_info->mount_opt & opt) {
 237                 btrfs_err(fs_info, "%s must be used with ro mount option",
 238                           opt_name);
 239                 return true;
 240         }
 241         return false;
 242 }
 243
 244 static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
 245 {
 246         char *opts;
 247         char *orig;
 248         char *p;
 249         substring_t args[MAX_OPT_ARGS];
 250         int ret = 0;
 251
 252         opts = kstrdup(options, GFP_KERNEL);
 253         if (!opts)
 254                 return -ENOMEM;
 255         orig = opts;
 256
 257         while ((p = strsep(&opts, ":")) != NULL) {
 258                 int token;
 259
 260                 if (!*p)
 261                         continue;
 262                 token = match_token(p, rescue_tokens, args);
 263                 switch (token){
 264                 case Opt_usebackuproot:
 265                         btrfs_info(info,
 266                                    "trying to use backup root at mount time");
 267                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 268                         break;
 269                 case Opt_nologreplay:
 270                         btrfs_set_and_info(info, NOLOGREPLAY,
 271                                            "disabling log replay at mount time");
 272                         break;
 273                 case Opt_ignorebadroots:
 274                         btrfs_set_and_info(info, IGNOREBADROOTS,
 275                                            "ignoring bad roots");
 276                         break;
 277                 case Opt_ignoredatacsums:
 278                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 279                                            "ignoring data csums");
 280                         break;
 281                 case Opt_rescue_all:
 282                         btrfs_info(info, "enabling all of the rescue options");
 283                         btrfs_set_and_info(info, IGNOREDATACSUMS,
 284                                            "ignoring data csums");
 285                         btrfs_set_and_info(info, IGNOREBADROOTS,
 286                                            "ignoring bad roots");
 287                         btrfs_set_and_info(info, NOLOGREPLAY,
 288                                            "disabling log replay at mount time");
 289                         break;
 290                 case Opt_err:
 291                         btrfs_info(info, "unrecognized rescue option '%s'", p);
 292                         ret = -EINVAL;
 293                         goto out;
 294                 default:
 295                         break;
 296                 }
 297
 298         }
 299 out:
 300         kfree(orig);
 301         return ret;
 302 }
 303
 304 /*
 305  * Regular mount options parser.  Everything that is needed only when
 306  * reading in a new superblock is parsed here.
 307  * XXX JDM: This needs to be cleaned up for remount.
 308  */
 309 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 310                         unsigned long new_flags)
 311 {
 312         substring_t args[MAX_OPT_ARGS];
 313         char *p, *num;
 314         int intarg;
 315         int ret = 0;
 316         char *compress_type;
 317         bool compress_force = false;
 318         enum btrfs_compression_type saved_compress_type;
 319         int saved_compress_level;
 320         bool saved_compress_force;
 321         int no_compress = 0;
 322         const bool remounting = test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state);
 323
 324         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 325                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 326         else if (btrfs_free_space_cache_v1_active(info)) {
 327                 if (btrfs_is_zoned(info)) {
 328                         btrfs_info(info,
 329                         "zoned: clearing existing space cache");
 330                         btrfs_set_super_cache_generation(info->super_copy, 0);
 331                 } else {
 332                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 333                 }
 334         }
 335
 336         /*
 337          * Even the options are empty, we still need to do extra check
 338          * against new flags
 339          */
 340         if (!options)
 341                 goto check;
 342
 343         while ((p = strsep(&options, ",")) != NULL) {
 344                 int token;
 345                 if (!*p)
 346                         continue;
 347
 348                 token = match_token(p, tokens, args);
 349                 switch (token) {
 350                 case Opt_degraded:
 351                         btrfs_info(info, "allowing degraded mounts");
 352                         btrfs_set_opt(info->mount_opt, DEGRADED);
 353                         break;
 354                 case Opt_subvol:
 355                 case Opt_subvol_empty:
 356                 case Opt_subvolid:
 357                 case Opt_device:
 358                         /*
 359                          * These are parsed by btrfs_parse_subvol_options or
 360                          * btrfs_parse_device_options and can be ignored here.
 361                          */
 362                         break;
 363                 case Opt_nodatasum:
 364                         btrfs_set_and_info(info, NODATASUM,
 365                                            "setting nodatasum");
 366                         break;
 367                 case Opt_datasum:
 368                         if (btrfs_test_opt(info, NODATASUM)) {
 369                                 if (btrfs_test_opt(info, NODATACOW))
 370                                         btrfs_info(info,
 371                                                    "setting datasum, datacow enabled");
 372                                 else
 373                                         btrfs_info(info, "setting datasum");
 374                         }
 375                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 376                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 377                         break;
 378                 case Opt_nodatacow:
 379                         if (!btrfs_test_opt(info, NODATACOW)) {
 380                                 if (!btrfs_test_opt(info, COMPRESS) ||
 381                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 382                                         btrfs_info(info,
 383                                                    "setting nodatacow, compression disabled");
 384                                 } else {
 385                                         btrfs_info(info, "setting nodatacow");
 386                                 }
 387                         }
 388                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 389                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 390                         btrfs_set_opt(info->mount_opt, NODATACOW);
 391                         btrfs_set_opt(info->mount_opt, NODATASUM);
 392                         break;
 393                 case Opt_datacow:
 394                         btrfs_clear_and_info(info, NODATACOW,
 395                                              "setting datacow");
 396                         break;
 397                 case Opt_compress_force:
 398                 case Opt_compress_force_type:
 399                         compress_force = true;
 400                         fallthrough;
 401                 case Opt_compress:
 402                 case Opt_compress_type:
 403                         saved_compress_type = btrfs_test_opt(info,
 404                                                              COMPRESS) ?
 405                                 info->compress_type : BTRFS_COMPRESS_NONE;
 406                         saved_compress_force =
 407                                 btrfs_test_opt(info, FORCE_COMPRESS);
 408                         saved_compress_level = info->compress_level;
 409                         if (token == Opt_compress ||
 410                             token == Opt_compress_force ||
 411                             strncmp(args[0].from, "zlib", 4) == 0) {
 412                                 compress_type = "zlib";
 413
 414                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 415                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
 416                                 /*
 417                                  * args[0] contains uninitialized data since
 418                                  * for these tokens we don't expect any
 419                                  * parameter.
 420                                  */
 421                                 if (token != Opt_compress &&
 422                                     token != Opt_compress_force)
 423                                         info->compress_level =
 424                                           btrfs_compress_str2level(
 425                                                         BTRFS_COMPRESS_ZLIB,
 426                                                         args[0].from + 4);
 427                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 428                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 429                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 430                                 no_compress = 0;
 431                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 432                                 compress_type = "lzo";
 433                                 info->compress_type = BTRFS_COMPRESS_LZO;
 434                                 info->compress_level = 0;
 435                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 436                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 437                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 438                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 439                                 no_compress = 0;
 440                         } else if (strncmp(args[0].from, "zstd", 4) == 0) {
 441                                 compress_type = "zstd";
 442                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
 443                                 info->compress_level =
 444                                         btrfs_compress_str2level(
 445                                                          BTRFS_COMPRESS_ZSTD,
 446                                                          args[0].from + 4);
 447                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 448                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 449                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 450                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
 451                                 no_compress = 0;
 452                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 453                                 compress_type = "no";
 454                                 info->compress_level = 0;
 455                                 info->compress_type = 0;
 456                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 457                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 458                                 compress_force = false;
 459                                 no_compress++;
 460                         } else {
 461                                 btrfs_err(info, "unrecognized compression value %s",
 462                                           args[0].from);
 463                                 ret = -EINVAL;
 464                                 goto out;
 465                         }
 466
 467                         if (compress_force) {
 468                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 469                         } else {
 470                                 /*
 471                                  * If we remount from compress-force=xxx to
 472                                  * compress=xxx, we need clear FORCE_COMPRESS
 473                                  * flag, otherwise, there is no way for users
 474                                  * to disable forcible compression separately.
 475                                  */
 476                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 477                         }
 478                         if (no_compress == 1) {
 479                                 btrfs_info(info, "use no compression");
 480                         } else if ((info->compress_type != saved_compress_type) ||
 481                                    (compress_force != saved_compress_force) ||
 482                                    (info->compress_level != saved_compress_level)) {
 483                                 btrfs_info(info, "%s %s compression, level %d",
 484                                            (compress_force) ? "force" : "use",
 485                                            compress_type, info->compress_level);
 486                         }
 487                         compress_force = false;
 488                         break;
 489                 case Opt_ssd:
 490                         btrfs_set_and_info(info, SSD,
 491                                            "enabling ssd optimizations");
 492                         btrfs_clear_opt(info->mount_opt, NOSSD);
 493                         break;
 494                 case Opt_ssd_spread:
 495                         btrfs_set_and_info(info, SSD,
 496                                            "enabling ssd optimizations");
 497                         btrfs_set_and_info(info, SSD_SPREAD,
 498                                            "using spread ssd allocation scheme");
 499                         btrfs_clear_opt(info->mount_opt, NOSSD);
 500                         break;
 501                 case Opt_nossd:
 502                         btrfs_set_opt(info->mount_opt, NOSSD);
 503                         btrfs_clear_and_info(info, SSD,
 504                                              "not using ssd optimizations");
 505                         fallthrough;
 506                 case Opt_nossd_spread:
 507                         btrfs_clear_and_info(info, SSD_SPREAD,
 508                                              "not using spread ssd allocation scheme");
 509                         break;
 510                 case Opt_barrier:
 511                         btrfs_clear_and_info(info, NOBARRIER,
 512                                              "turning on barriers");
 513                         break;
 514                 case Opt_nobarrier:
 515                         btrfs_set_and_info(info, NOBARRIER,
 516                                            "turning off barriers");
 517                         break;
 518                 case Opt_thread_pool:
 519                         ret = match_int(&args[0], &intarg);
 520                         if (ret) {
 521                                 btrfs_err(info, "unrecognized thread_pool value %s",
 522                                           args[0].from);
 523                                 goto out;
 524                         } else if (intarg == 0) {
 525                                 btrfs_err(info, "invalid value 0 for thread_pool");
 526                                 ret = -EINVAL;
 527                                 goto out;
 528                         }
 529                         info->thread_pool_size = intarg;
 530                         break;
 531                 case Opt_max_inline:
 532                         num = match_strdup(&args[0]);
 533                         if (num) {
 534                                 info->max_inline = memparse(num, NULL);
 535                                 kfree(num);
 536
 537                                 if (info->max_inline) {
 538                                         info->max_inline = min_t(u64,
 539                                                 info->max_inline,
 540                                                 info->sectorsize);
 541                                 }
 542                                 btrfs_info(info, "max_inline at %llu",
 543                                            info->max_inline);
 544                         } else {
 545                                 ret = -ENOMEM;
 546                                 goto out;
 547                         }
 548                         break;
 549                 case Opt_acl:
 550 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 551                         info->sb->s_flags |= SB_POSIXACL;
 552                         break;
 553 #else
 554                         btrfs_err(info, "support for ACL not compiled in!");
 555                         ret = -EINVAL;
 556                         goto out;
 557 #endif
 558                 case Opt_noacl:
 559                         info->sb->s_flags &= ~SB_POSIXACL;
 560                         break;
 561                 case Opt_notreelog:
 562                         btrfs_set_and_info(info, NOTREELOG,
 563                                            "disabling tree log");
 564                         break;
 565                 case Opt_treelog:
 566                         btrfs_clear_and_info(info, NOTREELOG,
 567                                              "enabling tree log");
 568                         break;
 569                 case Opt_norecovery:
 570                 case Opt_nologreplay:
 571                         btrfs_warn(info,
 572                 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
 573                         btrfs_set_and_info(info, NOLOGREPLAY,
 574                                            "disabling log replay at mount time");
 575                         break;
 576                 case Opt_flushoncommit:
 577                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 578                                            "turning on flush-on-commit");
 579                         break;
 580                 case Opt_noflushoncommit:
 581                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 582                                              "turning off flush-on-commit");
 583                         break;
 584                 case Opt_ratio:
 585                         ret = match_int(&args[0], &intarg);
 586                         if (ret) {
 587                                 btrfs_err(info, "unrecognized metadata_ratio value %s",
 588                                           args[0].from);
 589                                 goto out;
 590                         }
 591                         info->metadata_ratio = intarg;
 592                         btrfs_info(info, "metadata ratio %u",
 593                                    info->metadata_ratio);
 594                         break;
 595                 case Opt_discard:
 596                 case Opt_discard_mode:
 597                         if (token == Opt_discard ||
 598                             strcmp(args[0].from, "sync") == 0) {
 599                                 btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
 600                                 btrfs_set_and_info(info, DISCARD_SYNC,
 601                                                    "turning on sync discard");
 602                         } else if (strcmp(args[0].from, "async") == 0) {
 603                                 btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
 604                                 btrfs_set_and_info(info, DISCARD_ASYNC,
 605                                                    "turning on async discard");
 606                         } else {
 607                                 btrfs_err(info, "unrecognized discard mode value %s",
 608                                           args[0].from);
 609                                 ret = -EINVAL;
 610                                 goto out;
 611                         }
 612                         btrfs_clear_opt(info->mount_opt, NODISCARD);
 613                         break;
 614                 case Opt_nodiscard:
 615                         btrfs_clear_and_info(info, DISCARD_SYNC,
 616                                              "turning off discard");
 617                         btrfs_clear_and_info(info, DISCARD_ASYNC,
 618                                              "turning off async discard");
 619                         btrfs_set_opt(info->mount_opt, NODISCARD);
 620                         break;
 621                 case Opt_space_cache:
 622                 case Opt_space_cache_version:
 623                         /*
 624                          * We already set FREE_SPACE_TREE above because we have
 625                          * compat_ro(FREE_SPACE_TREE) set, and we aren't going
 626                          * to allow v1 to be set for extent tree v2, simply
 627                          * ignore this setting if we're extent tree v2.
 628                          */
 629                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 630                                 break;
 631                         if (token == Opt_space_cache ||
 632                             strcmp(args[0].from, "v1") == 0) {
 633                                 btrfs_clear_opt(info->mount_opt,
 634                                                 FREE_SPACE_TREE);
 635                                 btrfs_set_and_info(info, SPACE_CACHE,
 636                                            "enabling disk space caching");
 637                         } else if (strcmp(args[0].from, "v2") == 0) {
 638                                 btrfs_clear_opt(info->mount_opt,
 639                                                 SPACE_CACHE);
 640                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 641                                                    "enabling free space tree");
 642                         } else {
 643                                 btrfs_err(info, "unrecognized space_cache value %s",
 644                                           args[0].from);
 645                                 ret = -EINVAL;
 646                                 goto out;
 647                         }
 648                         break;
 649                 case Opt_rescan_uuid_tree:
 650                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 651                         break;
 652                 case Opt_no_space_cache:
 653                         /*
 654                          * We cannot operate without the free space tree with
 655                          * extent tree v2, ignore this option.
 656                          */
 657                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 658                                 break;
 659                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 660                                 btrfs_clear_and_info(info, SPACE_CACHE,
 661                                              "disabling disk space caching");
 662                         }
 663                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 664                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 665                                              "disabling free space tree");
 666                         }
 667                         break;
 668                 case Opt_inode_cache:
 669                 case Opt_noinode_cache:
 670                         btrfs_warn(info,
 671         "the 'inode_cache' option is deprecated and has no effect since 5.11");
 672                         break;
 673                 case Opt_clear_cache:
 674                         /*
 675                          * We cannot clear the free space tree with extent tree
 676                          * v2, ignore this option.
 677                          */
 678                         if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
 679                                 break;
 680                         btrfs_set_and_info(info, CLEAR_CACHE,
 681                                            "force clearing of disk cache");
 682                         break;
 683                 case Opt_user_subvol_rm_allowed:
 684                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 685                         break;
 686                 case Opt_enospc_debug:
 687                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 688                         break;
 689                 case Opt_noenospc_debug:
 690                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 691                         break;
 692                 case Opt_defrag:
 693                         btrfs_set_and_info(info, AUTO_DEFRAG,
 694                                            "enabling auto defrag");
 695                         break;
 696                 case Opt_nodefrag:
 697                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 698                                              "disabling auto defrag");
 699                         break;
 700                 case Opt_recovery:
 701                 case Opt_usebackuproot:
 702                         btrfs_warn(info,
 703                         "'%s' is deprecated, use 'rescue=usebackuproot' instead",
 704                                    token == Opt_recovery ? "recovery" :
 705                                    "usebackuproot");
 706                         btrfs_info(info,
 707                                    "trying to use backup root at mount time");
 708                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 709                         break;
 710                 case Opt_skip_balance:
 711                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 712                         break;
 713 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 714                 case Opt_check_integrity_including_extent_data:
 715                         btrfs_warn(info,
 716         "integrity checker is deprecated and will be removed in 6.7");
 717                         btrfs_info(info,
 718                                    "enabling check integrity including extent data");
 719                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY_DATA);
 720                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 721                         break;
 722                 case Opt_check_integrity:
 723                         btrfs_warn(info,
 724         "integrity checker is deprecated and will be removed in 6.7");
 725                         btrfs_info(info, "enabling check integrity");
 726                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 727                         break;
 728                 case Opt_check_integrity_print_mask:
 729                         ret = match_int(&args[0], &intarg);
 730                         if (ret) {
 731                                 btrfs_err(info,
 732                                 "unrecognized check_integrity_print_mask value %s",
 733                                         args[0].from);
 734                                 goto out;
 735                         }
 736                         info->check_integrity_print_mask = intarg;
 737                         btrfs_warn(info,
 738         "integrity checker is deprecated and will be removed in 6.7");
 739                         btrfs_info(info, "check_integrity_print_mask 0x%x",
 740                                    info->check_integrity_print_mask);
 741                         break;
 742 #else
 743                 case Opt_check_integrity_including_extent_data:
 744                 case Opt_check_integrity:
 745                 case Opt_check_integrity_print_mask:
 746                         btrfs_err(info,
 747                                   "support for check_integrity* not compiled in!");
 748                         ret = -EINVAL;
 749                         goto out;
 750 #endif
 751                 case Opt_fatal_errors:
 752                         if (strcmp(args[0].from, "panic") == 0) {
 753                                 btrfs_set_opt(info->mount_opt,
 754                                               PANIC_ON_FATAL_ERROR);
 755                         } else if (strcmp(args[0].from, "bug") == 0) {
 756                                 btrfs_clear_opt(info->mount_opt,
 757                                               PANIC_ON_FATAL_ERROR);
 758                         } else {
 759                                 btrfs_err(info, "unrecognized fatal_errors value %s",
 760                                           args[0].from);
 761                                 ret = -EINVAL;
 762                                 goto out;
 763                         }
 764                         break;
 765                 case Opt_commit_interval:
 766                         intarg = 0;
 767                         ret = match_int(&args[0], &intarg);
 768                         if (ret) {
 769                                 btrfs_err(info, "unrecognized commit_interval value %s",
 770                                           args[0].from);
 771                                 ret = -EINVAL;
 772                                 goto out;
 773                         }
 774                         if (intarg == 0) {
 775                                 btrfs_info(info,
 776                                            "using default commit interval %us",
 777                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 778                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
 779                         } else if (intarg > 300) {
 780                                 btrfs_warn(info, "excessive commit interval %d",
 781                                            intarg);
 782                         }
 783                         info->commit_interval = intarg;
 784                         break;
 785                 case Opt_rescue:
 786                         ret = parse_rescue_options(info, args[0].from);
 787                         if (ret < 0) {
 788                                 btrfs_err(info, "unrecognized rescue value %s",
 789                                           args[0].from);
 790                                 goto out;
 791                         }
 792                         break;
 793 #ifdef CONFIG_BTRFS_DEBUG
 794                 case Opt_fragment_all:
 795                         btrfs_info(info, "fragmenting all space");
 796                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 797                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 798                         break;
 799                 case Opt_fragment_metadata:
 800                         btrfs_info(info, "fragmenting metadata");
 801                         btrfs_set_opt(info->mount_opt,
 802                                       FRAGMENT_METADATA);
 803                         break;
 804                 case Opt_fragment_data:
 805                         btrfs_info(info, "fragmenting data");
 806                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 807                         break;
 808 #endif
 809 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 810                 case Opt_ref_verify:
 811                         btrfs_info(info, "doing ref verification");
 812                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
 813                         break;
 814 #endif
 815                 case Opt_err:
 816                         btrfs_err(info, "unrecognized mount option '%s'", p);
 817                         ret = -EINVAL;
 818                         goto out;
 819                 default:
 820                         break;
 821                 }
 822         }
 823 check:
 824         /* We're read-only, don't have to check. */
 825         if (new_flags & SB_RDONLY)
 826                 goto out;
 827
 828         if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
 829             check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
 830             check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))
 831                 ret = -EINVAL;
 832 out:
 833         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 834             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 835             !btrfs_test_opt(info, CLEAR_CACHE)) {
 836                 btrfs_err(info, "cannot disable free space tree");
 837                 ret = -EINVAL;
 838         }
 839         if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
 840              !btrfs_test_opt(info, FREE_SPACE_TREE)) {
 841                 btrfs_err(info, "cannot disable free space tree with block-group-tree feature");
 842                 ret = -EINVAL;
 843         }
 844         if (!ret)
 845                 ret = btrfs_check_mountopts_zoned(info);
 846         if (!ret && !remounting) {
 847                 if (btrfs_test_opt(info, SPACE_CACHE))
 848                         btrfs_info(info, "disk space caching is enabled");
 849                 if (btrfs_test_opt(info, FREE_SPACE_TREE))
 850                         btrfs_info(info, "using free space tree");
 851         }
 852         return ret;
 853 }
 854
 855 /*
 856  * Parse mount options that are required early in the mount process.
 857  *
 858  * All other options will be parsed on much later in the mount process and
 859  * only when we need to allocate a new super block.
 860  */
 861 static int btrfs_parse_device_options(const char *options, blk_mode_t flags)
 862 {
 863         substring_t args[MAX_OPT_ARGS];
 864         char *device_name, *opts, *orig, *p;
 865         struct btrfs_device *device = NULL;
 866         int error = 0;
 867
 868         lockdep_assert_held(&uuid_mutex);
 869
 870         if (!options)
 871                 return 0;
 872
 873         /*
 874          * strsep changes the string, duplicate it because btrfs_parse_options
 875          * gets called later
 876          */
 877         opts = kstrdup(options, GFP_KERNEL);
 878         if (!opts)
 879                 return -ENOMEM;
 880         orig = opts;
 881
 882         while ((p = strsep(&opts, ",")) != NULL) {
 883                 int token;
 884
 885                 if (!*p)
 886                         continue;
 887
 888                 token = match_token(p, tokens, args);
 889                 if (token == Opt_device) {
 890                         device_name = match_strdup(&args[0]);
 891                         if (!device_name) {
 892                                 error = -ENOMEM;
 893                                 goto out;
 894                         }
 895                         device = btrfs_scan_one_device(device_name, flags);
 896                         kfree(device_name);
 897                         if (IS_ERR(device)) {
 898                                 error = PTR_ERR(device);
 899                                 goto out;
 900                         }
 901                 }
 902         }
 903
 904 out:
 905         kfree(orig);
 906         return error;
 907 }
 908
 909 /*
 910  * Parse mount options that are related to subvolume id
 911  *
 912  * The value is later passed to mount_subvol()
 913  */
 914 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
 915                 u64 *subvol_objectid)
 916 {
 917         substring_t args[MAX_OPT_ARGS];
 918         char *opts, *orig, *p;
 919         int error = 0;
 920         u64 subvolid;
 921
 922         if (!options)
 923                 return 0;
 924
 925         /*
 926          * strsep changes the string, duplicate it because
 927          * btrfs_parse_device_options gets called later
 928          */
 929         opts = kstrdup(options, GFP_KERNEL);
 930         if (!opts)
 931                 return -ENOMEM;
 932         orig = opts;
 933
 934         while ((p = strsep(&opts, ",")) != NULL) {
 935                 int token;
 936                 if (!*p)
 937                         continue;
 938
 939                 token = match_token(p, tokens, args);
 940                 switch (token) {
 941                 case Opt_subvol:
 942                         kfree(*subvol_name);
 943                         *subvol_name = match_strdup(&args[0]);
 944                         if (!*subvol_name) {
 945                                 error = -ENOMEM;
 946                                 goto out;
 947                         }
 948                         break;
 949                 case Opt_subvolid:
 950                         error = match_u64(&args[0], &subvolid);
 951                         if (error)
 952                                 goto out;
 953
 954                         /* we want the original fs_tree */
 955                         if (subvolid == 0)
 956                                 subvolid = BTRFS_FS_TREE_OBJECTID;
 957
 958                         *subvol_objectid = subvolid;
 959                         break;
 960                 default:
 961                         break;
 962                 }
 963         }
 964
 965 out:
 966         kfree(orig);
 967         return error;
 968 }
 969
 970 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 971                                           u64 subvol_objectid)
 972 {
 973         struct btrfs_root *root = fs_info->tree_root;
 974         struct btrfs_root *fs_root = NULL;
 975         struct btrfs_root_ref *root_ref;
 976         struct btrfs_inode_ref *inode_ref;
 977         struct btrfs_key key;
 978         struct btrfs_path *path = NULL;
 979         char *name = NULL, *ptr;
 980         u64 dirid;
 981         int len;
 982         int ret;
 983
 984         path = btrfs_alloc_path();
 985         if (!path) {
 986                 ret = -ENOMEM;
 987                 goto err;
 988         }
 989
 990         name = kmalloc(PATH_MAX, GFP_KERNEL);
 991         if (!name) {
 992                 ret = -ENOMEM;
 993                 goto err;
 994         }
 995         ptr = name + PATH_MAX - 1;
 996         ptr[0] = '\0';
 997
 998         /*
 999          * Walk up the subvolume trees in the tree of tree roots by root
1000          * backrefs until we hit the top-level subvolume.
1001          */
1002         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1003                 key.objectid = subvol_objectid;
1004                 key.type = BTRFS_ROOT_BACKREF_KEY;
1005                 key.offset = (u64)-1;
1006
1007                 ret = btrfs_search_backwards(root, &key, path);
1008                 if (ret < 0) {
1009                         goto err;
1010                 } else if (ret > 0) {
1011                         ret = -ENOENT;
1012                         goto err;
1013                 }
1014
1015                 subvol_objectid = key.offset;
1016
1017                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1018                                           struct btrfs_root_ref);
1019                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1020                 ptr -= len + 1;
1021                 if (ptr < name) {
1022                         ret = -ENAMETOOLONG;
1023                         goto err;
1024                 }
1025                 read_extent_buffer(path->nodes[0], ptr + 1,
1026                                    (unsigned long)(root_ref + 1), len);
1027                 ptr[0] = '/';
1028                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1029                 btrfs_release_path(path);
1030
1031                 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
1032                 if (IS_ERR(fs_root)) {
1033                         ret = PTR_ERR(fs_root);
1034                         fs_root = NULL;
1035                         goto err;
1036                 }
1037
1038                 /*
1039                  * Walk up the filesystem tree by inode refs until we hit the
1040                  * root directory.
1041                  */
1042                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1043                         key.objectid = dirid;
1044                         key.type = BTRFS_INODE_REF_KEY;
1045                         key.offset = (u64)-1;
1046
1047                         ret = btrfs_search_backwards(fs_root, &key, path);
1048                         if (ret < 0) {
1049                                 goto err;
1050                         } else if (ret > 0) {
1051                                 ret = -ENOENT;
1052                                 goto err;
1053                         }
1054
1055                         dirid = key.offset;
1056
1057                         inode_ref = btrfs_item_ptr(path->nodes[0],
1058                                                    path->slots[0],
1059                                                    struct btrfs_inode_ref);
1060                         len = btrfs_inode_ref_name_len(path->nodes[0],
1061                                                        inode_ref);
1062                         ptr -= len + 1;
1063                         if (ptr < name) {
1064                                 ret = -ENAMETOOLONG;
1065                                 goto err;
1066                         }
1067                         read_extent_buffer(path->nodes[0], ptr + 1,
1068                                            (unsigned long)(inode_ref + 1), len);
1069                         ptr[0] = '/';
1070                         btrfs_release_path(path);
1071                 }
1072                 btrfs_put_root(fs_root);
1073                 fs_root = NULL;
1074         }
1075
1076         btrfs_free_path(path);
1077         if (ptr == name + PATH_MAX - 1) {
1078                 name[0] = '/';
1079                 name[1] = '\0';
1080         } else {
1081                 memmove(name, ptr, name + PATH_MAX - ptr);
1082         }
1083         return name;
1084
1085 err:
1086         btrfs_put_root(fs_root);
1087         btrfs_free_path(path);
1088         kfree(name);
1089         return ERR_PTR(ret);
1090 }
1091
1092 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1093 {
1094         struct btrfs_root *root = fs_info->tree_root;
1095         struct btrfs_dir_item *di;
1096         struct btrfs_path *path;
1097         struct btrfs_key location;
1098         struct fscrypt_str name = FSTR_INIT("default", 7);
1099         u64 dir_id;
1100
1101         path = btrfs_alloc_path();
1102         if (!path)
1103                 return -ENOMEM;
1104
1105         /*
1106          * Find the "default" dir item which points to the root item that we
1107          * will mount by default if we haven't been given a specific subvolume
1108          * to mount.
1109          */
1110         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1111         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
1112         if (IS_ERR(di)) {
1113                 btrfs_free_path(path);
1114                 return PTR_ERR(di);
1115         }
1116         if (!di) {
1117                 /*
1118                  * Ok the default dir item isn't there.  This is weird since
1119                  * it's always been there, but don't freak out, just try and
1120                  * mount the top-level subvolume.
1121                  */
1122                 btrfs_free_path(path);
1123                 *objectid = BTRFS_FS_TREE_OBJECTID;
1124                 return 0;
1125         }
1126
1127         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1128         btrfs_free_path(path);
1129         *objectid = location.objectid;
1130         return 0;
1131 }
1132
1133 static int btrfs_fill_super(struct super_block *sb,
1134                             struct btrfs_fs_devices *fs_devices,
1135                             void *data)
1136 {
1137         struct inode *inode;
1138         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1139         int err;
1140
1141         sb->s_maxbytes = MAX_LFS_FILESIZE;
1142         sb->s_magic = BTRFS_SUPER_MAGIC;
1143         sb->s_op = &btrfs_super_ops;
1144         sb->s_d_op = &btrfs_dentry_operations;
1145         sb->s_export_op = &btrfs_export_ops;
1146 #ifdef CONFIG_FS_VERITY
1147         sb->s_vop = &btrfs_verityops;
1148 #endif
1149         sb->s_xattr = btrfs_xattr_handlers;
1150         sb->s_time_gran = 1;
1151 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1152         sb->s_flags |= SB_POSIXACL;
1153 #endif
1154         sb->s_flags |= SB_I_VERSION;
1155         sb->s_iflags |= SB_I_CGROUPWB;
1156
1157         err = super_setup_bdi(sb);
1158         if (err) {
1159                 btrfs_err(fs_info, "super_setup_bdi failed");
1160                 return err;
1161         }
1162
1163         err = open_ctree(sb, fs_devices, (char *)data);
1164         if (err) {
1165                 btrfs_err(fs_info, "open_ctree failed");
1166                 return err;
1167         }
1168
1169         inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1170         if (IS_ERR(inode)) {
1171                 err = PTR_ERR(inode);
1172                 btrfs_handle_fs_error(fs_info, err, NULL);
1173                 goto fail_close;
1174         }
1175
1176         sb->s_root = d_make_root(inode);
1177         if (!sb->s_root) {
1178                 err = -ENOMEM;
1179                 goto fail_close;
1180         }
1181
1182         sb->s_flags |= SB_ACTIVE;
1183         return 0;
1184
1185 fail_close:
1186         close_ctree(fs_info);
1187         return err;
1188 }
1189
1190 int btrfs_sync_fs(struct super_block *sb, int wait)
1191 {
1192         struct btrfs_trans_handle *trans;
1193         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1194         struct btrfs_root *root = fs_info->tree_root;
1195
1196         trace_btrfs_sync_fs(fs_info, wait);
1197
1198         if (!wait) {
1199                 filemap_flush(fs_info->btree_inode->i_mapping);
1200                 return 0;
1201         }
1202
1203         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1204
1205         trans = btrfs_attach_transaction_barrier(root);
1206         if (IS_ERR(trans)) {
1207                 /* no transaction, don't bother */
1208                 if (PTR_ERR(trans) == -ENOENT) {
1209                         /*
1210                          * Exit unless we have some pending changes
1211                          * that need to go through commit
1212                          */
1213                         if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
1214                                       &fs_info->flags))
1215                                 return 0;
1216                         /*
1217                          * A non-blocking test if the fs is frozen. We must not
1218                          * start a new transaction here otherwise a deadlock
1219                          * happens. The pending operations are delayed to the
1220                          * next commit after thawing.
1221                          */
1222                         if (sb_start_write_trylock(sb))
1223                                 sb_end_write(sb);
1224                         else
1225                                 return 0;
1226                         trans = btrfs_start_transaction(root, 0);
1227                 }
1228                 if (IS_ERR(trans))
1229                         return PTR_ERR(trans);
1230         }
1231         return btrfs_commit_transaction(trans);
1232 }
1233
1234 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1235 {
1236         seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1237         *printed = true;
1238 }
1239
1240 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1241 {
1242         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1243         const char *compress_type;
1244         const char *subvol_name;
1245         bool printed = false;
1246
1247         if (btrfs_test_opt(info, DEGRADED))
1248                 seq_puts(seq, ",degraded");
1249         if (btrfs_test_opt(info, NODATASUM))
1250                 seq_puts(seq, ",nodatasum");
1251         if (btrfs_test_opt(info, NODATACOW))
1252                 seq_puts(seq, ",nodatacow");
1253         if (btrfs_test_opt(info, NOBARRIER))
1254                 seq_puts(seq, ",nobarrier");
1255         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1256                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1257         if (info->thread_pool_size !=  min_t(unsigned long,
1258                                              num_online_cpus() + 2, 8))
1259                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1260         if (btrfs_test_opt(info, COMPRESS)) {
1261                 compress_type = btrfs_compress_type2str(info->compress_type);
1262                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1263                         seq_printf(seq, ",compress-force=%s", compress_type);
1264                 else
1265                         seq_printf(seq, ",compress=%s", compress_type);
1266                 if (info->compress_level)
1267                         seq_printf(seq, ":%d", info->compress_level);
1268         }
1269         if (btrfs_test_opt(info, NOSSD))
1270                 seq_puts(seq, ",nossd");
1271         if (btrfs_test_opt(info, SSD_SPREAD))
1272                 seq_puts(seq, ",ssd_spread");
1273         else if (btrfs_test_opt(info, SSD))
1274                 seq_puts(seq, ",ssd");
1275         if (btrfs_test_opt(info, NOTREELOG))
1276                 seq_puts(seq, ",notreelog");
1277         if (btrfs_test_opt(info, NOLOGREPLAY))
1278                 print_rescue_option(seq, "nologreplay", &printed);
1279         if (btrfs_test_opt(info, USEBACKUPROOT))
1280                 print_rescue_option(seq, "usebackuproot", &printed);
1281         if (btrfs_test_opt(info, IGNOREBADROOTS))
1282                 print_rescue_option(seq, "ignorebadroots", &printed);
1283         if (btrfs_test_opt(info, IGNOREDATACSUMS))
1284                 print_rescue_option(seq, "ignoredatacsums", &printed);
1285         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1286                 seq_puts(seq, ",flushoncommit");
1287         if (btrfs_test_opt(info, DISCARD_SYNC))
1288                 seq_puts(seq, ",discard");
1289         if (btrfs_test_opt(info, DISCARD_ASYNC))
1290                 seq_puts(seq, ",discard=async");
1291         if (!(info->sb->s_flags & SB_POSIXACL))
1292                 seq_puts(seq, ",noacl");
1293         if (btrfs_free_space_cache_v1_active(info))
1294                 seq_puts(seq, ",space_cache");
1295         else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1296                 seq_puts(seq, ",space_cache=v2");
1297         else
1298                 seq_puts(seq, ",nospace_cache");
1299         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1300                 seq_puts(seq, ",rescan_uuid_tree");
1301         if (btrfs_test_opt(info, CLEAR_CACHE))
1302                 seq_puts(seq, ",clear_cache");
1303         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1304                 seq_puts(seq, ",user_subvol_rm_allowed");
1305         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1306                 seq_puts(seq, ",enospc_debug");
1307         if (btrfs_test_opt(info, AUTO_DEFRAG))
1308                 seq_puts(seq, ",autodefrag");
1309         if (btrfs_test_opt(info, SKIP_BALANCE))
1310                 seq_puts(seq, ",skip_balance");
1311 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1312         if (btrfs_test_opt(info, CHECK_INTEGRITY_DATA))
1313                 seq_puts(seq, ",check_int_data");
1314         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1315                 seq_puts(seq, ",check_int");
1316         if (info->check_integrity_print_mask)
1317                 seq_printf(seq, ",check_int_print_mask=%d",
1318                                 info->check_integrity_print_mask);
1319 #endif
1320         if (info->metadata_ratio)
1321                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1322         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1323                 seq_puts(seq, ",fatal_errors=panic");
1324         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1325                 seq_printf(seq, ",commit=%u", info->commit_interval);
1326 #ifdef CONFIG_BTRFS_DEBUG
1327         if (btrfs_test_opt(info, FRAGMENT_DATA))
1328                 seq_puts(seq, ",fragment=data");
1329         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1330                 seq_puts(seq, ",fragment=metadata");
1331 #endif
1332         if (btrfs_test_opt(info, REF_VERIFY))
1333                 seq_puts(seq, ",ref_verify");
1334         seq_printf(seq, ",subvolid=%llu",
1335                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1336         subvol_name = btrfs_get_subvol_name_from_objectid(info,
1337                         BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1338         if (!IS_ERR(subvol_name)) {
1339                 seq_puts(seq, ",subvol=");
1340                 seq_escape(seq, subvol_name, " \t\n\\");
1341                 kfree(subvol_name);
1342         }
1343         return 0;
1344 }
1345
1346 static int btrfs_test_super(struct super_block *s, void *data)
1347 {
1348         struct btrfs_fs_info *p = data;
1349         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1350
1351         return fs_info->fs_devices == p->fs_devices;
1352 }
1353
1354 static int btrfs_set_super(struct super_block *s, void *data)
1355 {
1356         int err = set_anon_super(s, data);
1357         if (!err)
1358                 s->s_fs_info = data;
1359         return err;
1360 }
1361
1362 /*
1363  * subvolumes are identified by ino 256
1364  */
1365 static inline int is_subvolume_inode(struct inode *inode)
1366 {
1367         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1368                 return 1;
1369         return 0;
1370 }
1371
1372 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1373                                    struct vfsmount *mnt)
1374 {
1375         struct dentry *root;
1376         int ret;
1377
1378         if (!subvol_name) {
1379                 if (!subvol_objectid) {
1380                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1381                                                           &subvol_objectid);
1382                         if (ret) {
1383                                 root = ERR_PTR(ret);
1384                                 goto out;
1385                         }
1386                 }
1387                 subvol_name = btrfs_get_subvol_name_from_objectid(
1388                                         btrfs_sb(mnt->mnt_sb), subvol_objectid);
1389                 if (IS_ERR(subvol_name)) {
1390                         root = ERR_CAST(subvol_name);
1391                         subvol_name = NULL;
1392                         goto out;
1393                 }
1394
1395         }
1396
1397         root = mount_subtree(mnt, subvol_name);
1398         /* mount_subtree() drops our reference on the vfsmount. */
1399         mnt = NULL;
1400
1401         if (!IS_ERR(root)) {
1402                 struct super_block *s = root->d_sb;
1403                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1404                 struct inode *root_inode = d_inode(root);
1405                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1406
1407                 ret = 0;
1408                 if (!is_subvolume_inode(root_inode)) {
1409                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1410                                subvol_name);
1411                         ret = -EINVAL;
1412                 }
1413                 if (subvol_objectid && root_objectid != subvol_objectid) {
1414                         /*
1415                          * This will also catch a race condition where a
1416                          * subvolume which was passed by ID is renamed and
1417                          * another subvolume is renamed over the old location.
1418                          */
1419                         btrfs_err(fs_info,
1420                                   "subvol '%s' does not match subvolid %llu",
1421                                   subvol_name, subvol_objectid);
1422                         ret = -EINVAL;
1423                 }
1424                 if (ret) {
1425                         dput(root);
1426                         root = ERR_PTR(ret);
1427                         deactivate_locked_super(s);
1428                 }
1429         }
1430
1431 out:
1432         mntput(mnt);
1433         kfree(subvol_name);
1434         return root;
1435 }
1436
1437 /*
1438  * Find a superblock for the given device / mount point.
1439  *
1440  * Note: This is based on mount_bdev from fs/super.c with a few additions
1441  *       for multiple device setup.  Make sure to keep it in sync.
1442  */
1443 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1444                 int flags, const char *device_name, void *data)
1445 {
1446         struct block_device *bdev = NULL;
1447         struct super_block *s;
1448         struct btrfs_device *device = NULL;
1449         struct btrfs_fs_devices *fs_devices = NULL;
1450         struct btrfs_fs_info *fs_info = NULL;
1451         void *new_sec_opts = NULL;
1452         blk_mode_t mode = sb_open_mode(flags);
1453         int error = 0;
1454
1455         if (data) {
1456                 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1457                 if (error)
1458                         return ERR_PTR(error);
1459         }
1460
1461         /*
1462          * Setup a dummy root and fs_info for test/set super.  This is because
1463          * we don't actually fill this stuff out until open_ctree, but we need
1464          * then open_ctree will properly initialize the file system specific
1465          * settings later.  btrfs_init_fs_info initializes the static elements
1466          * of the fs_info (locks and such) to make cleanup easier if we find a
1467          * superblock with our given fs_devices later on at sget() time.
1468          */
1469         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1470         if (!fs_info) {
1471                 error = -ENOMEM;
1472                 goto error_sec_opts;
1473         }
1474         btrfs_init_fs_info(fs_info);
1475
1476         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1477         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1478         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1479                 error = -ENOMEM;
1480                 goto error_fs_info;
1481         }
1482
1483         mutex_lock(&uuid_mutex);
1484         error = btrfs_parse_device_options(data, mode);
1485         if (error) {
1486                 mutex_unlock(&uuid_mutex);
1487                 goto error_fs_info;
1488         }
1489
1490         device = btrfs_scan_one_device(device_name, mode);
1491         if (IS_ERR(device)) {
1492                 mutex_unlock(&uuid_mutex);
1493                 error = PTR_ERR(device);
1494                 goto error_fs_info;
1495         }
1496
1497         fs_devices = device->fs_devices;
1498         fs_info->fs_devices = fs_devices;
1499
1500         error = btrfs_open_devices(fs_devices, mode, fs_type);
1501         mutex_unlock(&uuid_mutex);
1502         if (error)
1503                 goto error_fs_info;
1504
1505         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1506                 error = -EACCES;
1507                 goto error_close_devices;
1508         }
1509
1510         bdev = fs_devices->latest_dev->bdev;
1511         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1512                  fs_info);
1513         if (IS_ERR(s)) {
1514                 error = PTR_ERR(s);
1515                 goto error_close_devices;
1516         }
1517
1518         if (s->s_root) {
1519                 btrfs_close_devices(fs_devices);
1520                 btrfs_free_fs_info(fs_info);
1521                 if ((flags ^ s->s_flags) & SB_RDONLY)
1522                         error = -EBUSY;
1523         } else {
1524                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1525                 shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name,
1526                                         s->s_id);
1527                 btrfs_sb(s)->bdev_holder = fs_type;
1528                 error = btrfs_fill_super(s, fs_devices, data);
1529         }
1530         if (!error)
1531                 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1532         security_free_mnt_opts(&new_sec_opts);
1533         if (error) {
1534                 deactivate_locked_super(s);
1535                 return ERR_PTR(error);
1536         }
1537
1538         return dget(s->s_root);
1539
1540 error_close_devices:
1541         btrfs_close_devices(fs_devices);
1542 error_fs_info:
1543         btrfs_free_fs_info(fs_info);
1544 error_sec_opts:
1545         security_free_mnt_opts(&new_sec_opts);
1546         return ERR_PTR(error);
1547 }
1548
1549 /*
1550  * Mount function which is called by VFS layer.
1551  *
1552  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1553  * which needs vfsmount* of device's root (/).  This means device's root has to
1554  * be mounted internally in any case.
1555  *
1556  * Operation flow:
1557  *   1. Parse subvol id related options for later use in mount_subvol().
1558  *
1559  *   2. Mount device's root (/) by calling vfs_kern_mount().
1560  *
1561  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1562  *      first place. In order to avoid calling btrfs_mount() again, we use
1563  *      different file_system_type which is not registered to VFS by
1564  *      register_filesystem() (btrfs_root_fs_type). As a result,
1565  *      btrfs_mount_root() is called. The return value will be used by
1566  *      mount_subtree() in mount_subvol().
1567  *
1568  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1569  *      "btrfs subvolume set-default", mount_subvol() is called always.
1570  */
1571 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1572                 const char *device_name, void *data)
1573 {
1574         struct vfsmount *mnt_root;
1575         struct dentry *root;
1576         char *subvol_name = NULL;
1577         u64 subvol_objectid = 0;
1578         int error = 0;
1579
1580         error = btrfs_parse_subvol_options(data, &subvol_name,
1581                                         &subvol_objectid);
1582         if (error) {
1583                 kfree(subvol_name);
1584                 return ERR_PTR(error);
1585         }
1586
1587         /* mount device's root (/) */
1588         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1589         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1590                 if (flags & SB_RDONLY) {
1591                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1592                                 flags & ~SB_RDONLY, device_name, data);
1593                 } else {
1594                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1595                                 flags | SB_RDONLY, device_name, data);
1596                         if (IS_ERR(mnt_root)) {
1597                                 root = ERR_CAST(mnt_root);
1598                                 kfree(subvol_name);
1599                                 goto out;
1600                         }
1601
1602                         down_write(&mnt_root->mnt_sb->s_umount);
1603                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1604                         up_write(&mnt_root->mnt_sb->s_umount);
1605                         if (error < 0) {
1606                                 root = ERR_PTR(error);
1607                                 mntput(mnt_root);
1608                                 kfree(subvol_name);
1609                                 goto out;
1610                         }
1611                 }
1612         }
1613         if (IS_ERR(mnt_root)) {
1614                 root = ERR_CAST(mnt_root);
1615                 kfree(subvol_name);
1616                 goto out;
1617         }
1618
1619         /* mount_subvol() will free subvol_name and mnt_root */
1620         root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1621
1622 out:
1623         return root;
1624 }
1625
1626 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1627                                      u32 new_pool_size, u32 old_pool_size)
1628 {
1629         if (new_pool_size == old_pool_size)
1630                 return;
1631
1632         fs_info->thread_pool_size = new_pool_size;
1633
1634         btrfs_info(fs_info, "resize thread pool %d -> %d",
1635                old_pool_size, new_pool_size);
1636
1637         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1638         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1639         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1640         workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1641         workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1642         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1643         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1644         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1645 }
1646
1647 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1648                                        unsigned long old_opts, int flags)
1649 {
1650         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1651             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1652              (flags & SB_RDONLY))) {
1653                 /* wait for any defraggers to finish */
1654                 wait_event(fs_info->transaction_wait,
1655                            (atomic_read(&fs_info->defrag_running) == 0));
1656                 if (flags & SB_RDONLY)
1657                         sync_filesystem(fs_info->sb);
1658         }
1659 }
1660
1661 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1662                                          unsigned long old_opts)
1663 {
1664         const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1665
1666         /*
1667          * We need to cleanup all defragable inodes if the autodefragment is
1668          * close or the filesystem is read only.
1669          */
1670         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1671             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1672                 btrfs_cleanup_defrag_inodes(fs_info);
1673         }
1674
1675         /* If we toggled discard async */
1676         if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1677             btrfs_test_opt(fs_info, DISCARD_ASYNC))
1678                 btrfs_discard_resume(fs_info);
1679         else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1680                  !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1681                 btrfs_discard_cleanup(fs_info);
1682
1683         /* If we toggled space cache */
1684         if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1685                 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1686 }
1687
1688 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1689 {
1690         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1691         unsigned old_flags = sb->s_flags;
1692         unsigned long old_opts = fs_info->mount_opt;
1693         unsigned long old_compress_type = fs_info->compress_type;
1694         u64 old_max_inline = fs_info->max_inline;
1695         u32 old_thread_pool_size = fs_info->thread_pool_size;
1696         u32 old_metadata_ratio = fs_info->metadata_ratio;
1697         int ret;
1698
1699         sync_filesystem(sb);
1700         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1701
1702         if (data) {
1703                 void *new_sec_opts = NULL;
1704
1705                 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1706                 if (!ret)
1707                         ret = security_sb_remount(sb, new_sec_opts);
1708                 security_free_mnt_opts(&new_sec_opts);
1709                 if (ret)
1710                         goto restore;
1711         }
1712
1713         ret = btrfs_parse_options(fs_info, data, *flags);
1714         if (ret)
1715                 goto restore;
1716
1717         ret = btrfs_check_features(fs_info, !(*flags & SB_RDONLY));
1718         if (ret < 0)
1719                 goto restore;
1720
1721         btrfs_remount_begin(fs_info, old_opts, *flags);
1722         btrfs_resize_thread_pool(fs_info,
1723                 fs_info->thread_pool_size, old_thread_pool_size);
1724
1725         if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1726             (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1727             (!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
1728                 btrfs_warn(fs_info,
1729                 "remount supports changing free space tree only from ro to rw");
1730                 /* Make sure free space cache options match the state on disk */
1731                 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1732                         btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1733                         btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1734                 }
1735                 if (btrfs_free_space_cache_v1_active(fs_info)) {
1736                         btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1737                         btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1738                 }
1739         }
1740
1741         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1742                 goto out;
1743
1744         if (*flags & SB_RDONLY) {
1745                 /*
1746                  * this also happens on 'umount -rf' or on shutdown, when
1747                  * the filesystem is busy.
1748                  */
1749                 cancel_work_sync(&fs_info->async_reclaim_work);
1750                 cancel_work_sync(&fs_info->async_data_reclaim_work);
1751
1752                 btrfs_discard_cleanup(fs_info);
1753
1754                 /* wait for the uuid_scan task to finish */
1755                 down(&fs_info->uuid_tree_rescan_sem);
1756                 /* avoid complains from lockdep et al. */
1757                 up(&fs_info->uuid_tree_rescan_sem);
1758
1759                 btrfs_set_sb_rdonly(sb);
1760
1761                 /*
1762                  * Setting SB_RDONLY will put the cleaner thread to
1763                  * sleep at the next loop if it's already active.
1764                  * If it's already asleep, we'll leave unused block
1765                  * groups on disk until we're mounted read-write again
1766                  * unless we clean them up here.
1767                  */
1768                 btrfs_delete_unused_bgs(fs_info);
1769
1770                 /*
1771                  * The cleaner task could be already running before we set the
1772                  * flag BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock).
1773                  * We must make sure that after we finish the remount, i.e. after
1774                  * we call btrfs_commit_super(), the cleaner can no longer start
1775                  * a transaction - either because it was dropping a dead root,
1776                  * running delayed iputs or deleting an unused block group (the
1777                  * cleaner picked a block group from the list of unused block
1778                  * groups before we were able to in the previous call to
1779                  * btrfs_delete_unused_bgs()).
1780                  */
1781                 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING,
1782                             TASK_UNINTERRUPTIBLE);
1783
1784                 /*
1785                  * We've set the superblock to RO mode, so we might have made
1786                  * the cleaner task sleep without running all pending delayed
1787                  * iputs. Go through all the delayed iputs here, so that if an
1788                  * unmount happens without remounting RW we don't end up at
1789                  * finishing close_ctree() with a non-empty list of delayed
1790                  * iputs.
1791                  */
1792                 btrfs_run_delayed_iputs(fs_info);
1793
1794                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1795                 btrfs_scrub_cancel(fs_info);
1796                 btrfs_pause_balance(fs_info);
1797
1798                 /*
1799                  * Pause the qgroup rescan worker if it is running. We don't want
1800                  * it to be still running after we are in RO mode, as after that,
1801                  * by the time we unmount, it might have left a transaction open,
1802                  * so we would leak the transaction and/or crash.
1803                  */
1804                 btrfs_qgroup_wait_for_completion(fs_info, false);
1805
1806                 ret = btrfs_commit_super(fs_info);
1807                 if (ret)
1808                         goto restore;
1809         } else {
1810                 if (BTRFS_FS_ERROR(fs_info)) {
1811                         btrfs_err(fs_info,
1812                                 "Remounting read-write after error is not allowed");
1813                         ret = -EINVAL;
1814                         goto restore;
1815                 }
1816                 if (fs_info->fs_devices->rw_devices == 0) {
1817                         ret = -EACCES;
1818                         goto restore;
1819                 }
1820
1821                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1822                         btrfs_warn(fs_info,
1823                 "too many missing devices, writable remount is not allowed");
1824                         ret = -EACCES;
1825                         goto restore;
1826                 }
1827
1828                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1829                         btrfs_warn(fs_info,
1830                 "mount required to replay tree-log, cannot remount read-write");
1831                         ret = -EINVAL;
1832                         goto restore;
1833                 }
1834
1835                 /*
1836                  * NOTE: when remounting with a change that does writes, don't
1837                  * put it anywhere above this point, as we are not sure to be
1838                  * safe to write until we pass the above checks.
1839                  */
1840                 ret = btrfs_start_pre_rw_mount(fs_info);
1841                 if (ret)
1842                         goto restore;
1843
1844                 btrfs_clear_sb_rdonly(sb);
1845
1846                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1847
1848                 /*
1849                  * If we've gone from readonly -> read/write, we need to get
1850                  * our sync/async discard lists in the right state.
1851                  */
1852                 btrfs_discard_resume(fs_info);
1853         }
1854 out:
1855         /*
1856          * We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
1857          * since the absence of the flag means it can be toggled off by remount.
1858          */
1859         *flags |= SB_I_VERSION;
1860
1861         wake_up_process(fs_info->transaction_kthread);
1862         btrfs_remount_cleanup(fs_info, old_opts);
1863         btrfs_clear_oneshot_options(fs_info);
1864         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1865
1866         return 0;
1867
1868 restore:
1869         /* We've hit an error - don't reset SB_RDONLY */
1870         if (sb_rdonly(sb))
1871                 old_flags |= SB_RDONLY;
1872         if (!(old_flags & SB_RDONLY))
1873                 clear_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
1874         sb->s_flags = old_flags;
1875         fs_info->mount_opt = old_opts;
1876         fs_info->compress_type = old_compress_type;
1877         fs_info->max_inline = old_max_inline;
1878         btrfs_resize_thread_pool(fs_info,
1879                 old_thread_pool_size, fs_info->thread_pool_size);
1880         fs_info->metadata_ratio = old_metadata_ratio;
1881         btrfs_remount_cleanup(fs_info, old_opts);
1882         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1883
1884         return ret;
1885 }
1886
1887 /* Used to sort the devices by max_avail(descending sort) */
1888 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1889 {
1890         const struct btrfs_device_info *dev_info1 = a;
1891         const struct btrfs_device_info *dev_info2 = b;
1892
1893         if (dev_info1->max_avail > dev_info2->max_avail)
1894                 return -1;
1895         else if (dev_info1->max_avail < dev_info2->max_avail)
1896                 return 1;
1897         return 0;
1898 }
1899
1900 /*
1901  * sort the devices by max_avail, in which max free extent size of each device
1902  * is stored.(Descending Sort)
1903  */
1904 static inline void btrfs_descending_sort_devices(
1905                                         struct btrfs_device_info *devices,
1906                                         size_t nr_devices)
1907 {
1908         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1909              btrfs_cmp_device_free_bytes, NULL);
1910 }
1911
1912 /*
1913  * The helper to calc the free space on the devices that can be used to store
1914  * file data.
1915  */
1916 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1917                                               u64 *free_bytes)
1918 {
1919         struct btrfs_device_info *devices_info;
1920         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1921         struct btrfs_device *device;
1922         u64 type;
1923         u64 avail_space;
1924         u64 min_stripe_size;
1925         int num_stripes = 1;
1926         int i = 0, nr_devices;
1927         const struct btrfs_raid_attr *rattr;
1928
1929         /*
1930          * We aren't under the device list lock, so this is racy-ish, but good
1931          * enough for our purposes.
1932          */
1933         nr_devices = fs_info->fs_devices->open_devices;
1934         if (!nr_devices) {
1935                 smp_mb();
1936                 nr_devices = fs_info->fs_devices->open_devices;
1937                 ASSERT(nr_devices);
1938                 if (!nr_devices) {
1939                         *free_bytes = 0;
1940                         return 0;
1941                 }
1942         }
1943
1944         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1945                                GFP_KERNEL);
1946         if (!devices_info)
1947                 return -ENOMEM;
1948
1949         /* calc min stripe number for data space allocation */
1950         type = btrfs_data_alloc_profile(fs_info);
1951         rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1952
1953         if (type & BTRFS_BLOCK_GROUP_RAID0)
1954                 num_stripes = nr_devices;
1955         else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1956                 num_stripes = rattr->ncopies;
1957         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1958                 num_stripes = 4;
1959
1960         /* Adjust for more than 1 stripe per device */
1961         min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1962
1963         rcu_read_lock();
1964         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1965                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1966                                                 &device->dev_state) ||
1967                     !device->bdev ||
1968                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1969                         continue;
1970
1971                 if (i >= nr_devices)
1972                         break;
1973
1974                 avail_space = device->total_bytes - device->bytes_used;
1975
1976                 /* align with stripe_len */
1977                 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1978
1979                 /*
1980                  * Ensure we have at least min_stripe_size on top of the
1981                  * reserved space on the device.
1982                  */
1983                 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1984                         continue;
1985
1986                 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1987
1988                 devices_info[i].dev = device;
1989                 devices_info[i].max_avail = avail_space;
1990
1991                 i++;
1992         }
1993         rcu_read_unlock();
1994
1995         nr_devices = i;
1996
1997         btrfs_descending_sort_devices(devices_info, nr_devices);
1998
1999         i = nr_devices - 1;
2000         avail_space = 0;
2001         while (nr_devices >= rattr->devs_min) {
2002                 num_stripes = min(num_stripes, nr_devices);
2003
2004                 if (devices_info[i].max_avail >= min_stripe_size) {
2005                         int j;
2006                         u64 alloc_size;
2007
2008                         avail_space += devices_info[i].max_avail * num_stripes;
2009                         alloc_size = devices_info[i].max_avail;
2010                         for (j = i + 1 - num_stripes; j <= i; j++)
2011                                 devices_info[j].max_avail -= alloc_size;
2012                 }
2013                 i--;
2014                 nr_devices--;
2015         }
2016
2017         kfree(devices_info);
2018         *free_bytes = avail_space;
2019         return 0;
2020 }
2021
2022 /*
2023  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2024  *
2025  * If there's a redundant raid level at DATA block groups, use the respective
2026  * multiplier to scale the sizes.
2027  *
2028  * Unused device space usage is based on simulating the chunk allocator
2029  * algorithm that respects the device sizes and order of allocations.  This is
2030  * a close approximation of the actual use but there are other factors that may
2031  * change the result (like a new metadata chunk).
2032  *
2033  * If metadata is exhausted, f_bavail will be 0.
2034  */
2035 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2036 {
2037         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2038         struct btrfs_super_block *disk_super = fs_info->super_copy;
2039         struct btrfs_space_info *found;
2040         u64 total_used = 0;
2041         u64 total_free_data = 0;
2042         u64 total_free_meta = 0;
2043         u32 bits = fs_info->sectorsize_bits;
2044         __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2045         unsigned factor = 1;
2046         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2047         int ret;
2048         u64 thresh = 0;
2049         int mixed = 0;
2050
2051         list_for_each_entry(found, &fs_info->space_info, list) {
2052                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2053                         int i;
2054
2055                         total_free_data += found->disk_total - found->disk_used;
2056                         total_free_data -=
2057                                 btrfs_account_ro_block_groups_free_space(found);
2058
2059                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2060                                 if (!list_empty(&found->block_groups[i]))
2061                                         factor = btrfs_bg_type_to_factor(
2062                                                 btrfs_raid_array[i].bg_flag);
2063                         }
2064                 }
2065
2066                 /*
2067                  * Metadata in mixed block group profiles are accounted in data
2068                  */
2069                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2070                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2071                                 mixed = 1;
2072                         else
2073                                 total_free_meta += found->disk_total -
2074                                         found->disk_used;
2075                 }
2076
2077                 total_used += found->disk_used;
2078         }
2079
2080         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2081         buf->f_blocks >>= bits;
2082         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2083
2084         /* Account global block reserve as used, it's in logical size already */
2085         spin_lock(&block_rsv->lock);
2086         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2087         if (buf->f_bfree >= block_rsv->size >> bits)
2088                 buf->f_bfree -= block_rsv->size >> bits;
2089         else
2090                 buf->f_bfree = 0;
2091         spin_unlock(&block_rsv->lock);
2092
2093         buf->f_bavail = div_u64(total_free_data, factor);
2094         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2095         if (ret)
2096                 return ret;
2097         buf->f_bavail += div_u64(total_free_data, factor);
2098         buf->f_bavail = buf->f_bavail >> bits;
2099
2100         /*
2101          * We calculate the remaining metadata space minus global reserve. If
2102          * this is (supposedly) smaller than zero, there's no space. But this
2103          * does not hold in practice, the exhausted state happens where's still
2104          * some positive delta. So we apply some guesswork and compare the
2105          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2106          *
2107          * We probably cannot calculate the exact threshold value because this
2108          * depends on the internal reservations requested by various
2109          * operations, so some operations that consume a few metadata will
2110          * succeed even if the Avail is zero. But this is better than the other
2111          * way around.
2112          */
2113         thresh = SZ_4M;
2114
2115         /*
2116          * We only want to claim there's no available space if we can no longer
2117          * allocate chunks for our metadata profile and our global reserve will
2118          * not fit in the free metadata space.  If we aren't ->full then we
2119          * still can allocate chunks and thus are fine using the currently
2120          * calculated f_bavail.
2121          */
2122         if (!mixed && block_rsv->space_info->full &&
2123             (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size))
2124                 buf->f_bavail = 0;
2125
2126         buf->f_type = BTRFS_SUPER_MAGIC;
2127         buf->f_bsize = dentry->d_sb->s_blocksize;
2128         buf->f_namelen = BTRFS_NAME_LEN;
2129
2130         /* We treat it as constant endianness (it doesn't matter _which_)
2131            because we want the fsid to come out the same whether mounted
2132            on a big-endian or little-endian host */
2133         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2134         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2135         /* Mask in the root object ID too, to disambiguate subvols */
2136         buf->f_fsid.val[0] ^=
2137                 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2138         buf->f_fsid.val[1] ^=
2139                 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2140
2141         return 0;
2142 }
2143
2144 static void btrfs_kill_super(struct super_block *sb)
2145 {
2146         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2147         kill_anon_super(sb);
2148         btrfs_free_fs_info(fs_info);
2149 }
2150
2151 static struct file_system_type btrfs_fs_type = {
2152         .owner          = THIS_MODULE,
2153         .name           = "btrfs",
2154         .mount          = btrfs_mount,
2155         .kill_sb        = btrfs_kill_super,
2156         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2157 };
2158
2159 static struct file_system_type btrfs_root_fs_type = {
2160         .owner          = THIS_MODULE,
2161         .name           = "btrfs",
2162         .mount          = btrfs_mount_root,
2163         .kill_sb        = btrfs_kill_super,
2164         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2165 };
2166
2167 MODULE_ALIAS_FS("btrfs");
2168
2169 static int btrfs_control_open(struct inode *inode, struct file *file)
2170 {
2171         /*
2172          * The control file's private_data is used to hold the
2173          * transaction when it is started and is used to keep
2174          * track of whether a transaction is already in progress.
2175          */
2176         file->private_data = NULL;
2177         return 0;
2178 }
2179
2180 /*
2181  * Used by /dev/btrfs-control for devices ioctls.
2182  */
2183 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2184                                 unsigned long arg)
2185 {
2186         struct btrfs_ioctl_vol_args *vol;
2187         struct btrfs_device *device = NULL;
2188         dev_t devt = 0;
2189         int ret = -ENOTTY;
2190
2191         if (!capable(CAP_SYS_ADMIN))
2192                 return -EPERM;
2193
2194         vol = memdup_user((void __user *)arg, sizeof(*vol));
2195         if (IS_ERR(vol))
2196                 return PTR_ERR(vol);
2197         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2198
2199         switch (cmd) {
2200         case BTRFS_IOC_SCAN_DEV:
2201                 mutex_lock(&uuid_mutex);
2202                 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ);
2203                 ret = PTR_ERR_OR_ZERO(device);
2204                 mutex_unlock(&uuid_mutex);
2205                 break;
2206         case BTRFS_IOC_FORGET_DEV:
2207                 if (vol->name[0] != 0) {
2208                         ret = lookup_bdev(vol->name, &devt);
2209                         if (ret)
2210                                 break;
2211                 }
2212                 ret = btrfs_forget_devices(devt);
2213                 break;
2214         case BTRFS_IOC_DEVICES_READY:
2215                 mutex_lock(&uuid_mutex);
2216                 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ);
2217                 if (IS_ERR(device)) {
2218                         mutex_unlock(&uuid_mutex);
2219                         ret = PTR_ERR(device);
2220                         break;
2221                 }
2222                 ret = !(device->fs_devices->num_devices ==
2223                         device->fs_devices->total_devices);
2224                 mutex_unlock(&uuid_mutex);
2225                 break;
2226         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2227                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2228                 break;
2229         }
2230
2231         kfree(vol);
2232         return ret;
2233 }
2234
2235 static int btrfs_freeze(struct super_block *sb)
2236 {
2237         struct btrfs_trans_handle *trans;
2238         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2239         struct btrfs_root *root = fs_info->tree_root;
2240
2241         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2242         /*
2243          * We don't need a barrier here, we'll wait for any transaction that
2244          * could be in progress on other threads (and do delayed iputs that
2245          * we want to avoid on a frozen filesystem), or do the commit
2246          * ourselves.
2247          */
2248         trans = btrfs_attach_transaction_barrier(root);
2249         if (IS_ERR(trans)) {
2250                 /* no transaction, don't bother */
2251                 if (PTR_ERR(trans) == -ENOENT)
2252                         return 0;
2253                 return PTR_ERR(trans);
2254         }
2255         return btrfs_commit_transaction(trans);
2256 }
2257
2258 static int check_dev_super(struct btrfs_device *dev)
2259 {
2260         struct btrfs_fs_info *fs_info = dev->fs_info;
2261         struct btrfs_super_block *sb;
2262         u16 csum_type;
2263         int ret = 0;
2264
2265         /* This should be called with fs still frozen. */
2266         ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2267
2268         /* Missing dev, no need to check. */
2269         if (!dev->bdev)
2270                 return 0;
2271
2272         /* Only need to check the primary super block. */
2273         sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2274         if (IS_ERR(sb))
2275                 return PTR_ERR(sb);
2276
2277         /* Verify the checksum. */
2278         csum_type = btrfs_super_csum_type(sb);
2279         if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2280                 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2281                           csum_type, btrfs_super_csum_type(fs_info->super_copy));
2282                 ret = -EUCLEAN;
2283                 goto out;
2284         }
2285
2286         if (btrfs_check_super_csum(fs_info, sb)) {
2287                 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2288                 ret = -EUCLEAN;
2289                 goto out;
2290         }
2291
2292         /* Btrfs_validate_super() includes fsid check against super->fsid. */
2293         ret = btrfs_validate_super(fs_info, sb, 0);
2294         if (ret < 0)
2295                 goto out;
2296
2297         if (btrfs_super_generation(sb) != fs_info->last_trans_committed) {
2298                 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2299                         btrfs_super_generation(sb),
2300                         fs_info->last_trans_committed);
2301                 ret = -EUCLEAN;
2302                 goto out;
2303         }
2304 out:
2305         btrfs_release_disk_super(sb);
2306         return ret;
2307 }
2308
2309 static int btrfs_unfreeze(struct super_block *sb)
2310 {
2311         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2312         struct btrfs_device *device;
2313         int ret = 0;
2314
2315         /*
2316          * Make sure the fs is not changed by accident (like hibernation then
2317          * modified by other OS).
2318          * If we found anything wrong, we mark the fs error immediately.
2319          *
2320          * And since the fs is frozen, no one can modify the fs yet, thus
2321          * we don't need to hold device_list_mutex.
2322          */
2323         list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2324                 ret = check_dev_super(device);
2325                 if (ret < 0) {
2326                         btrfs_handle_fs_error(fs_info, ret,
2327                                 "super block on devid %llu got modified unexpectedly",
2328                                 device->devid);
2329                         break;
2330                 }
2331         }
2332         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2333
2334         /*
2335          * We still return 0, to allow VFS layer to unfreeze the fs even the
2336          * above checks failed. Since the fs is either fine or read-only, we're
2337          * safe to continue, without causing further damage.
2338          */
2339         return 0;
2340 }
2341
2342 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2343 {
2344         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2345
2346         /*
2347          * There should be always a valid pointer in latest_dev, it may be stale
2348          * for a short moment in case it's being deleted but still valid until
2349          * the end of RCU grace period.
2350          */
2351         rcu_read_lock();
2352         seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2353         rcu_read_unlock();
2354
2355         return 0;
2356 }
2357
2358 static const struct super_operations btrfs_super_ops = {
2359         .drop_inode     = btrfs_drop_inode,
2360         .evict_inode    = btrfs_evict_inode,
2361         .put_super      = btrfs_put_super,
2362         .sync_fs        = btrfs_sync_fs,
2363         .show_options   = btrfs_show_options,
2364         .show_devname   = btrfs_show_devname,
2365         .alloc_inode    = btrfs_alloc_inode,
2366         .destroy_inode  = btrfs_destroy_inode,
2367         .free_inode     = btrfs_free_inode,
2368         .statfs         = btrfs_statfs,
2369         .remount_fs     = btrfs_remount,
2370         .freeze_fs      = btrfs_freeze,
2371         .unfreeze_fs    = btrfs_unfreeze,
2372 };
2373
2374 static const struct file_operations btrfs_ctl_fops = {
2375         .open = btrfs_control_open,
2376         .unlocked_ioctl  = btrfs_control_ioctl,
2377         .compat_ioctl = compat_ptr_ioctl,
2378         .owner   = THIS_MODULE,
2379         .llseek = noop_llseek,
2380 };
2381
2382 static struct miscdevice btrfs_misc = {
2383         .minor          = BTRFS_MINOR,
2384         .name           = "btrfs-control",
2385         .fops           = &btrfs_ctl_fops
2386 };
2387
2388 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2389 MODULE_ALIAS("devname:btrfs-control");
2390
2391 static int __init btrfs_interface_init(void)
2392 {
2393         return misc_register(&btrfs_misc);
2394 }
2395
2396 static __cold void btrfs_interface_exit(void)
2397 {
2398         misc_deregister(&btrfs_misc);
2399 }
2400
2401 static int __init btrfs_print_mod_info(void)
2402 {
2403         static const char options[] = ""
2404 #ifdef CONFIG_BTRFS_DEBUG
2405                         ", debug=on"
2406 #endif
2407 #ifdef CONFIG_BTRFS_ASSERT
2408                         ", assert=on"
2409 #endif
2410 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2411                         ", integrity-checker=on"
2412 #endif
2413 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2414                         ", ref-verify=on"
2415 #endif
2416 #ifdef CONFIG_BLK_DEV_ZONED
2417                         ", zoned=yes"
2418 #else
2419                         ", zoned=no"
2420 #endif
2421 #ifdef CONFIG_FS_VERITY
2422                         ", fsverity=yes"
2423 #else
2424                         ", fsverity=no"
2425 #endif
2426                         ;
2427         pr_info("Btrfs loaded%s\n", options);
2428         return 0;
2429 }
2430
2431 static int register_btrfs(void)
2432 {
2433         return register_filesystem(&btrfs_fs_type);
2434 }
2435
2436 static void unregister_btrfs(void)
2437 {
2438         unregister_filesystem(&btrfs_fs_type);
2439 }
2440
2441 /* Helper structure for long init/exit functions. */
2442 struct init_sequence {
2443         int (*init_func)(void);
2444         /* Can be NULL if the init_func doesn't need cleanup. */
2445         void (*exit_func)(void);
2446 };
2447
2448 static const struct init_sequence mod_init_seq[] = {
2449         {
2450                 .init_func = btrfs_props_init,
2451                 .exit_func = NULL,
2452         }, {
2453                 .init_func = btrfs_init_sysfs,
2454                 .exit_func = btrfs_exit_sysfs,
2455         }, {
2456                 .init_func = btrfs_init_compress,
2457                 .exit_func = btrfs_exit_compress,
2458         }, {
2459                 .init_func = btrfs_init_cachep,
2460                 .exit_func = btrfs_destroy_cachep,
2461         }, {
2462                 .init_func = btrfs_transaction_init,
2463                 .exit_func = btrfs_transaction_exit,
2464         }, {
2465                 .init_func = btrfs_ctree_init,
2466                 .exit_func = btrfs_ctree_exit,
2467         }, {
2468                 .init_func = btrfs_free_space_init,
2469                 .exit_func = btrfs_free_space_exit,
2470         }, {
2471                 .init_func = extent_state_init_cachep,
2472                 .exit_func = extent_state_free_cachep,
2473         }, {
2474                 .init_func = extent_buffer_init_cachep,
2475                 .exit_func = extent_buffer_free_cachep,
2476         }, {
2477                 .init_func = btrfs_bioset_init,
2478                 .exit_func = btrfs_bioset_exit,
2479         }, {
2480                 .init_func = extent_map_init,
2481                 .exit_func = extent_map_exit,
2482         }, {
2483                 .init_func = ordered_data_init,
2484                 .exit_func = ordered_data_exit,
2485         }, {
2486                 .init_func = btrfs_delayed_inode_init,
2487                 .exit_func = btrfs_delayed_inode_exit,
2488         }, {
2489                 .init_func = btrfs_auto_defrag_init,
2490                 .exit_func = btrfs_auto_defrag_exit,
2491         }, {
2492                 .init_func = btrfs_delayed_ref_init,
2493                 .exit_func = btrfs_delayed_ref_exit,
2494         }, {
2495                 .init_func = btrfs_prelim_ref_init,
2496                 .exit_func = btrfs_prelim_ref_exit,
2497         }, {
2498                 .init_func = btrfs_interface_init,
2499                 .exit_func = btrfs_interface_exit,
2500         }, {
2501                 .init_func = btrfs_print_mod_info,
2502                 .exit_func = NULL,
2503         }, {
2504                 .init_func = btrfs_run_sanity_tests,
2505                 .exit_func = NULL,
2506         }, {
2507                 .init_func = register_btrfs,
2508                 .exit_func = unregister_btrfs,
2509         }
2510 };
2511
2512 static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2513
2514 static __always_inline void btrfs_exit_btrfs_fs(void)
2515 {
2516         int i;
2517
2518         for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2519                 if (!mod_init_result[i])
2520                         continue;
2521                 if (mod_init_seq[i].exit_func)
2522                         mod_init_seq[i].exit_func();
2523                 mod_init_result[i] = false;
2524         }
2525 }
2526
2527 static void __exit exit_btrfs_fs(void)
2528 {
2529         btrfs_exit_btrfs_fs();
2530         btrfs_cleanup_fs_uuids();
2531 }
2532
2533 static int __init init_btrfs_fs(void)
2534 {
2535         int ret;
2536         int i;
2537
2538         for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2539                 ASSERT(!mod_init_result[i]);
2540                 ret = mod_init_seq[i].init_func();
2541                 if (ret < 0) {
2542                         btrfs_exit_btrfs_fs();
2543                         return ret;
2544                 }
2545                 mod_init_result[i] = true;
2546         }
2547         return 0;
2548 }
2549
2550 late_initcall(init_btrfs_fs);
2551 module_exit(exit_btrfs_fs)
2552
2553 MODULE_LICENSE("GPL");
2554 MODULE_SOFTDEP("pre: crc32c");
2555 MODULE_SOFTDEP("pre: xxhash64");
2556 MODULE_SOFTDEP("pre: sha256");
2557 MODULE_SOFTDEP("pre: blake2b-256");