fs/btrfs/super.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/fs.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/highmem.h>
  25 #include <linux/time.h>
  26 #include <linux/init.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mount.h>
  31 #include <linux/mpage.h>
  32 #include <linux/swap.h>
  33 #include <linux/writeback.h>
  34 #include <linux/statfs.h>
  35 #include <linux/compat.h>
  36 #include <linux/parser.h>
  37 #include <linux/ctype.h>
  38 #include <linux/namei.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/magic.h>
  41 #include <linux/slab.h>
  42 #include <linux/cleancache.h>
  43 #include <linux/ratelimit.h>
  44 #include <linux/btrfs.h>
  45 #include "delayed-inode.h"
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "hash.h"
  52 #include "props.h"
  53 #include "xattr.h"
  54 #include "volumes.h"
  55 #include "export.h"
  56 #include "compression.h"
  57 #include "rcu-string.h"
  58 #include "dev-replace.h"
  59 #include "free-space-cache.h"
  60 #include "backref.h"
  61 #include "tests/btrfs-tests.h"
  62
  63 #include "qgroup.h"
  64 #define CREATE_TRACE_POINTS
  65 #include <trace/events/btrfs.h>
  66
  67 static const struct super_operations btrfs_super_ops;
  68 static struct file_system_type btrfs_fs_type;
  69
  70 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  71
  72 const char *btrfs_decode_error(int errno)
  73 {
  74         char *errstr = "unknown";
  75
  76         switch (errno) {
  77         case -EIO:
  78                 errstr = "IO failure";
  79                 break;
  80         case -ENOMEM:
  81                 errstr = "Out of memory";
  82                 break;
  83         case -EROFS:
  84                 errstr = "Readonly filesystem";
  85                 break;
  86         case -EEXIST:
  87                 errstr = "Object already exists";
  88                 break;
  89         case -ENOSPC:
  90                 errstr = "No space left";
  91                 break;
  92         case -ENOENT:
  93                 errstr = "No such entry";
  94                 break;
  95         }
  96
  97         return errstr;
  98 }
  99
 100 /* btrfs handle error by forcing the filesystem readonly */
 101 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 102 {
 103         struct super_block *sb = fs_info->sb;
 104
 105         if (sb->s_flags & MS_RDONLY)
 106                 return;
 107
 108         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 109                 sb->s_flags |= MS_RDONLY;
 110                 btrfs_info(fs_info, "forced readonly");
 111                 /*
 112                  * Note that a running device replace operation is not
 113                  * canceled here although there is no way to update
 114                  * the progress. It would add the risk of a deadlock,
 115                  * therefore the canceling is omitted. The only penalty
 116                  * is that some I/O remains active until the procedure
 117                  * completes. The next time when the filesystem is
 118                  * mounted writeable again, the device replace
 119                  * operation continues.
 120                  */
 121         }
 122 }
 123
 124 /*
 125  * __btrfs_handle_fs_error decodes expected errors from the caller and
 126  * invokes the approciate error response.
 127  */
 128 __cold
 129 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 130                        unsigned int line, int errno, const char *fmt, ...)
 131 {
 132         struct super_block *sb = fs_info->sb;
 133 #ifdef CONFIG_PRINTK
 134         const char *errstr;
 135 #endif
 136
 137         /*
 138          * Special case: if the error is EROFS, and we're already
 139          * under MS_RDONLY, then it is safe here.
 140          */
 141         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 142                 return;
 143
 144 #ifdef CONFIG_PRINTK
 145         errstr = btrfs_decode_error(errno);
 146         if (fmt) {
 147                 struct va_format vaf;
 148                 va_list args;
 149
 150                 va_start(args, fmt);
 151                 vaf.fmt = fmt;
 152                 vaf.va = &args;
 153
 154                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 155                         sb->s_id, function, line, errno, errstr, &vaf);
 156                 va_end(args);
 157         } else {
 158                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 159                         sb->s_id, function, line, errno, errstr);
 160         }
 161 #endif
 162
 163         /*
 164          * Today we only save the error info to memory.  Long term we'll
 165          * also send it down to the disk
 166          */
 167         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 168
 169         /* Don't go through full error handling during mount */
 170         if (sb->s_flags & MS_BORN)
 171                 btrfs_handle_error(fs_info);
 172 }
 173
 174 #ifdef CONFIG_PRINTK
 175 static const char * const logtypes[] = {
 176         "emergency",
 177         "alert",
 178         "critical",
 179         "error",
 180         "warning",
 181         "notice",
 182         "info",
 183         "debug",
 184 };
 185
 186
 187 /*
 188  * Use one ratelimit state per log level so that a flood of less important
 189  * messages doesn't cause more important ones to be dropped.
 190  */
 191 static struct ratelimit_state printk_limits[] = {
 192         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 193         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 194         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 195         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 196         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 197         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 198         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 199         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 200 };
 201
 202 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 203 {
 204         struct super_block *sb = fs_info->sb;
 205         char lvl[4];
 206         struct va_format vaf;
 207         va_list args;
 208         const char *type = logtypes[4];
 209         int kern_level;
 210         struct ratelimit_state *ratelimit;
 211
 212         va_start(args, fmt);
 213
 214         kern_level = printk_get_level(fmt);
 215         if (kern_level) {
 216                 size_t size = printk_skip_level(fmt) - fmt;
 217                 memcpy(lvl, fmt,  size);
 218                 lvl[size] = '\0';
 219                 fmt += size;
 220                 type = logtypes[kern_level - '0'];
 221                 ratelimit = &printk_limits[kern_level - '0'];
 222         } else {
 223                 *lvl = '\0';
 224                 /* Default to debug output */
 225                 ratelimit = &printk_limits[7];
 226         }
 227
 228         vaf.fmt = fmt;
 229         vaf.va = &args;
 230
 231         if (__ratelimit(ratelimit))
 232                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
 233
 234         va_end(args);
 235 }
 236 #endif
 237
 238 /*
 239  * We only mark the transaction aborted and then set the file system read-only.
 240  * This will prevent new transactions from starting or trying to join this
 241  * one.
 242  *
 243  * This means that error recovery at the call site is limited to freeing
 244  * any local memory allocations and passing the error code up without
 245  * further cleanup. The transaction should complete as it normally would
 246  * in the call path but will return -EIO.
 247  *
 248  * We'll complete the cleanup in btrfs_end_transaction and
 249  * btrfs_commit_transaction.
 250  */
 251 __cold
 252 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 253                                const char *function,
 254                                unsigned int line, int errno)
 255 {
 256         struct btrfs_fs_info *fs_info = trans->fs_info;
 257
 258         trans->aborted = errno;
 259         /* Nothing used. The other threads that have joined this
 260          * transaction may be able to continue. */
 261         if (!trans->dirty && list_empty(&trans->new_bgs)) {
 262                 const char *errstr;
 263
 264                 errstr = btrfs_decode_error(errno);
 265                 btrfs_warn(fs_info,
 266                            "%s:%d: Aborting unused transaction(%s).",
 267                            function, line, errstr);
 268                 return;
 269         }
 270         ACCESS_ONCE(trans->transaction->aborted) = errno;
 271         /* Wake up anybody who may be waiting on this transaction */
 272         wake_up(&fs_info->transaction_wait);
 273         wake_up(&fs_info->transaction_blocked_wait);
 274         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 275 }
 276 /*
 277  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 278  * issues an alert, and either panics or BUGs, depending on mount options.
 279  */
 280 __cold
 281 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 282                    unsigned int line, int errno, const char *fmt, ...)
 283 {
 284         char *s_id = "<unknown>";
 285         const char *errstr;
 286         struct va_format vaf = { .fmt = fmt };
 287         va_list args;
 288
 289         if (fs_info)
 290                 s_id = fs_info->sb->s_id;
 291
 292         va_start(args, fmt);
 293         vaf.va = &args;
 294
 295         errstr = btrfs_decode_error(errno);
 296         if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
 297                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 298                         s_id, function, line, &vaf, errno, errstr);
 299
 300         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 301                    function, line, &vaf, errno, errstr);
 302         va_end(args);
 303         /* Caller calls BUG() */
 304 }
 305
 306 static void btrfs_put_super(struct super_block *sb)
 307 {
 308         close_ctree(btrfs_sb(sb)->tree_root);
 309 }
 310
 311 enum {
 312         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 313         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 314         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 315         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 316         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 317         Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 318         Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 319         Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 320         Opt_skip_balance, Opt_check_integrity,
 321         Opt_check_integrity_including_extent_data,
 322         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 323         Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
 324         Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
 325         Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
 326         Opt_nologreplay, Opt_norecovery,
 327 #ifdef CONFIG_BTRFS_DEBUG
 328         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 329 #endif
 330         Opt_err,
 331 };
 332
 333 static const match_table_t tokens = {
 334         {Opt_degraded, "degraded"},
 335         {Opt_subvol, "subvol=%s"},
 336         {Opt_subvolid, "subvolid=%s"},
 337         {Opt_device, "device=%s"},
 338         {Opt_nodatasum, "nodatasum"},
 339         {Opt_datasum, "datasum"},
 340         {Opt_nodatacow, "nodatacow"},
 341         {Opt_datacow, "datacow"},
 342         {Opt_nobarrier, "nobarrier"},
 343         {Opt_barrier, "barrier"},
 344         {Opt_max_inline, "max_inline=%s"},
 345         {Opt_alloc_start, "alloc_start=%s"},
 346         {Opt_thread_pool, "thread_pool=%d"},
 347         {Opt_compress, "compress"},
 348         {Opt_compress_type, "compress=%s"},
 349         {Opt_compress_force, "compress-force"},
 350         {Opt_compress_force_type, "compress-force=%s"},
 351         {Opt_ssd, "ssd"},
 352         {Opt_ssd_spread, "ssd_spread"},
 353         {Opt_nossd, "nossd"},
 354         {Opt_acl, "acl"},
 355         {Opt_noacl, "noacl"},
 356         {Opt_notreelog, "notreelog"},
 357         {Opt_treelog, "treelog"},
 358         {Opt_nologreplay, "nologreplay"},
 359         {Opt_norecovery, "norecovery"},
 360         {Opt_flushoncommit, "flushoncommit"},
 361         {Opt_noflushoncommit, "noflushoncommit"},
 362         {Opt_ratio, "metadata_ratio=%d"},
 363         {Opt_discard, "discard"},
 364         {Opt_nodiscard, "nodiscard"},
 365         {Opt_space_cache, "space_cache"},
 366         {Opt_space_cache_version, "space_cache=%s"},
 367         {Opt_clear_cache, "clear_cache"},
 368         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 369         {Opt_enospc_debug, "enospc_debug"},
 370         {Opt_noenospc_debug, "noenospc_debug"},
 371         {Opt_subvolrootid, "subvolrootid=%d"},
 372         {Opt_defrag, "autodefrag"},
 373         {Opt_nodefrag, "noautodefrag"},
 374         {Opt_inode_cache, "inode_cache"},
 375         {Opt_noinode_cache, "noinode_cache"},
 376         {Opt_no_space_cache, "nospace_cache"},
 377         {Opt_recovery, "recovery"}, /* deprecated */
 378         {Opt_usebackuproot, "usebackuproot"},
 379         {Opt_skip_balance, "skip_balance"},
 380         {Opt_check_integrity, "check_int"},
 381         {Opt_check_integrity_including_extent_data, "check_int_data"},
 382         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 383         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 384         {Opt_fatal_errors, "fatal_errors=%s"},
 385         {Opt_commit_interval, "commit=%d"},
 386 #ifdef CONFIG_BTRFS_DEBUG
 387         {Opt_fragment_data, "fragment=data"},
 388         {Opt_fragment_metadata, "fragment=metadata"},
 389         {Opt_fragment_all, "fragment=all"},
 390 #endif
 391         {Opt_err, NULL},
 392 };
 393
 394 /*
 395  * Regular mount options parser.  Everything that is needed only when
 396  * reading in a new superblock is parsed here.
 397  * XXX JDM: This needs to be cleaned up for remount.
 398  */
 399 int btrfs_parse_options(struct btrfs_root *root, char *options,
 400                         unsigned long new_flags)
 401 {
 402         struct btrfs_fs_info *info = root->fs_info;
 403         substring_t args[MAX_OPT_ARGS];
 404         char *p, *num, *orig = NULL;
 405         u64 cache_gen;
 406         int intarg;
 407         int ret = 0;
 408         char *compress_type;
 409         bool compress_force = false;
 410         enum btrfs_compression_type saved_compress_type;
 411         bool saved_compress_force;
 412         int no_compress = 0;
 413
 414         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 415         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
 416                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 417         else if (cache_gen)
 418                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 419
 420         /*
 421          * Even the options are empty, we still need to do extra check
 422          * against new flags
 423          */
 424         if (!options)
 425                 goto check;
 426
 427         /*
 428          * strsep changes the string, duplicate it because parse_options
 429          * gets called twice
 430          */
 431         options = kstrdup(options, GFP_NOFS);
 432         if (!options)
 433                 return -ENOMEM;
 434
 435         orig = options;
 436
 437         while ((p = strsep(&options, ",")) != NULL) {
 438                 int token;
 439                 if (!*p)
 440                         continue;
 441
 442                 token = match_token(p, tokens, args);
 443                 switch (token) {
 444                 case Opt_degraded:
 445                         btrfs_info(root->fs_info, "allowing degraded mounts");
 446                         btrfs_set_opt(info->mount_opt, DEGRADED);
 447                         break;
 448                 case Opt_subvol:
 449                 case Opt_subvolid:
 450                 case Opt_subvolrootid:
 451                 case Opt_device:
 452                         /*
 453                          * These are parsed by btrfs_parse_early_options
 454                          * and can be happily ignored here.
 455                          */
 456                         break;
 457                 case Opt_nodatasum:
 458                         btrfs_set_and_info(info, NODATASUM,
 459                                            "setting nodatasum");
 460                         break;
 461                 case Opt_datasum:
 462                         if (btrfs_test_opt(info, NODATASUM)) {
 463                                 if (btrfs_test_opt(info, NODATACOW))
 464                                         btrfs_info(root->fs_info,
 465                                                    "setting datasum, datacow enabled");
 466                                 else
 467                                         btrfs_info(root->fs_info,
 468                                                    "setting datasum");
 469                         }
 470                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 471                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 472                         break;
 473                 case Opt_nodatacow:
 474                         if (!btrfs_test_opt(info, NODATACOW)) {
 475                                 if (!btrfs_test_opt(info, COMPRESS) ||
 476                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 477                                         btrfs_info(root->fs_info,
 478                                                    "setting nodatacow, compression disabled");
 479                                 } else {
 480                                         btrfs_info(root->fs_info,
 481                                                    "setting nodatacow");
 482                                 }
 483                         }
 484                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 485                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 486                         btrfs_set_opt(info->mount_opt, NODATACOW);
 487                         btrfs_set_opt(info->mount_opt, NODATASUM);
 488                         break;
 489                 case Opt_datacow:
 490                         btrfs_clear_and_info(info, NODATACOW,
 491                                              "setting datacow");
 492                         break;
 493                 case Opt_compress_force:
 494                 case Opt_compress_force_type:
 495                         compress_force = true;
 496                         /* Fallthrough */
 497                 case Opt_compress:
 498                 case Opt_compress_type:
 499                         saved_compress_type = btrfs_test_opt(info,
 500                                                              COMPRESS) ?
 501                                 info->compress_type : BTRFS_COMPRESS_NONE;
 502                         saved_compress_force =
 503                                 btrfs_test_opt(info, FORCE_COMPRESS);
 504                         if (token == Opt_compress ||
 505                             token == Opt_compress_force ||
 506                             strcmp(args[0].from, "zlib") == 0) {
 507                                 compress_type = "zlib";
 508                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 509                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 510                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 511                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 512                                 no_compress = 0;
 513                         } else if (strcmp(args[0].from, "lzo") == 0) {
 514                                 compress_type = "lzo";
 515                                 info->compress_type = BTRFS_COMPRESS_LZO;
 516                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 517                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 518                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 519                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 520                                 no_compress = 0;
 521                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 522                                 compress_type = "no";
 523                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 524                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 525                                 compress_force = false;
 526                                 no_compress++;
 527                         } else {
 528                                 ret = -EINVAL;
 529                                 goto out;
 530                         }
 531
 532                         if (compress_force) {
 533                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 534                         } else {
 535                                 /*
 536                                  * If we remount from compress-force=xxx to
 537                                  * compress=xxx, we need clear FORCE_COMPRESS
 538                                  * flag, otherwise, there is no way for users
 539                                  * to disable forcible compression separately.
 540                                  */
 541                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 542                         }
 543                         if ((btrfs_test_opt(info, COMPRESS) &&
 544                              (info->compress_type != saved_compress_type ||
 545                               compress_force != saved_compress_force)) ||
 546                             (!btrfs_test_opt(info, COMPRESS) &&
 547                              no_compress == 1)) {
 548                                 btrfs_info(root->fs_info,
 549                                            "%s %s compression",
 550                                            (compress_force) ? "force" : "use",
 551                                            compress_type);
 552                         }
 553                         compress_force = false;
 554                         break;
 555                 case Opt_ssd:
 556                         btrfs_set_and_info(info, SSD,
 557                                            "use ssd allocation scheme");
 558                         break;
 559                 case Opt_ssd_spread:
 560                         btrfs_set_and_info(info, SSD_SPREAD,
 561                                            "use spread ssd allocation scheme");
 562                         btrfs_set_opt(info->mount_opt, SSD);
 563                         break;
 564                 case Opt_nossd:
 565                         btrfs_set_and_info(info, NOSSD,
 566                                              "not using ssd allocation scheme");
 567                         btrfs_clear_opt(info->mount_opt, SSD);
 568                         break;
 569                 case Opt_barrier:
 570                         btrfs_clear_and_info(info, NOBARRIER,
 571                                              "turning on barriers");
 572                         break;
 573                 case Opt_nobarrier:
 574                         btrfs_set_and_info(info, NOBARRIER,
 575                                            "turning off barriers");
 576                         break;
 577                 case Opt_thread_pool:
 578                         ret = match_int(&args[0], &intarg);
 579                         if (ret) {
 580                                 goto out;
 581                         } else if (intarg > 0) {
 582                                 info->thread_pool_size = intarg;
 583                         } else {
 584                                 ret = -EINVAL;
 585                                 goto out;
 586                         }
 587                         break;
 588                 case Opt_max_inline:
 589                         num = match_strdup(&args[0]);
 590                         if (num) {
 591                                 info->max_inline = memparse(num, NULL);
 592                                 kfree(num);
 593
 594                                 if (info->max_inline) {
 595                                         info->max_inline = min_t(u64,
 596                                                 info->max_inline,
 597                                                 root->sectorsize);
 598                                 }
 599                                 btrfs_info(root->fs_info, "max_inline at %llu",
 600                                         info->max_inline);
 601                         } else {
 602                                 ret = -ENOMEM;
 603                                 goto out;
 604                         }
 605                         break;
 606                 case Opt_alloc_start:
 607                         num = match_strdup(&args[0]);
 608                         if (num) {
 609                                 mutex_lock(&info->chunk_mutex);
 610                                 info->alloc_start = memparse(num, NULL);
 611                                 mutex_unlock(&info->chunk_mutex);
 612                                 kfree(num);
 613                                 btrfs_info(root->fs_info,
 614                                            "allocations start at %llu",
 615                                            info->alloc_start);
 616                         } else {
 617                                 ret = -ENOMEM;
 618                                 goto out;
 619                         }
 620                         break;
 621                 case Opt_acl:
 622 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 623                         root->fs_info->sb->s_flags |= MS_POSIXACL;
 624                         break;
 625 #else
 626                         btrfs_err(root->fs_info,
 627                                 "support for ACL not compiled in!");
 628                         ret = -EINVAL;
 629                         goto out;
 630 #endif
 631                 case Opt_noacl:
 632                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 633                         break;
 634                 case Opt_notreelog:
 635                         btrfs_set_and_info(info, NOTREELOG,
 636                                            "disabling tree log");
 637                         break;
 638                 case Opt_treelog:
 639                         btrfs_clear_and_info(info, NOTREELOG,
 640                                              "enabling tree log");
 641                         break;
 642                 case Opt_norecovery:
 643                 case Opt_nologreplay:
 644                         btrfs_set_and_info(info, NOLOGREPLAY,
 645                                            "disabling log replay at mount time");
 646                         break;
 647                 case Opt_flushoncommit:
 648                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 649                                            "turning on flush-on-commit");
 650                         break;
 651                 case Opt_noflushoncommit:
 652                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 653                                              "turning off flush-on-commit");
 654                         break;
 655                 case Opt_ratio:
 656                         ret = match_int(&args[0], &intarg);
 657                         if (ret) {
 658                                 goto out;
 659                         } else if (intarg >= 0) {
 660                                 info->metadata_ratio = intarg;
 661                                 btrfs_info(root->fs_info, "metadata ratio %d",
 662                                        info->metadata_ratio);
 663                         } else {
 664                                 ret = -EINVAL;
 665                                 goto out;
 666                         }
 667                         break;
 668                 case Opt_discard:
 669                         btrfs_set_and_info(info, DISCARD,
 670                                            "turning on discard");
 671                         break;
 672                 case Opt_nodiscard:
 673                         btrfs_clear_and_info(info, DISCARD,
 674                                              "turning off discard");
 675                         break;
 676                 case Opt_space_cache:
 677                 case Opt_space_cache_version:
 678                         if (token == Opt_space_cache ||
 679                             strcmp(args[0].from, "v1") == 0) {
 680                                 btrfs_clear_opt(root->fs_info->mount_opt,
 681                                                 FREE_SPACE_TREE);
 682                                 btrfs_set_and_info(info, SPACE_CACHE,
 683                                                    "enabling disk space caching");
 684                         } else if (strcmp(args[0].from, "v2") == 0) {
 685                                 btrfs_clear_opt(root->fs_info->mount_opt,
 686                                                 SPACE_CACHE);
 687                                 btrfs_set_and_info(info,
 688                                                    FREE_SPACE_TREE,
 689                                                    "enabling free space tree");
 690                         } else {
 691                                 ret = -EINVAL;
 692                                 goto out;
 693                         }
 694                         break;
 695                 case Opt_rescan_uuid_tree:
 696                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 697                         break;
 698                 case Opt_no_space_cache:
 699                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 700                                 btrfs_clear_and_info(info,
 701                                                      SPACE_CACHE,
 702                                                      "disabling disk space caching");
 703                         }
 704                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 705                                 btrfs_clear_and_info(info,
 706                                                      FREE_SPACE_TREE,
 707                                                      "disabling free space tree");
 708                         }
 709                         break;
 710                 case Opt_inode_cache:
 711                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 712                                            "enabling inode map caching");
 713                         break;
 714                 case Opt_noinode_cache:
 715                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 716                                              "disabling inode map caching");
 717                         break;
 718                 case Opt_clear_cache:
 719                         btrfs_set_and_info(info, CLEAR_CACHE,
 720                                            "force clearing of disk cache");
 721                         break;
 722                 case Opt_user_subvol_rm_allowed:
 723                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 724                         break;
 725                 case Opt_enospc_debug:
 726                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 727                         break;
 728                 case Opt_noenospc_debug:
 729                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 730                         break;
 731                 case Opt_defrag:
 732                         btrfs_set_and_info(info, AUTO_DEFRAG,
 733                                            "enabling auto defrag");
 734                         break;
 735                 case Opt_nodefrag:
 736                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 737                                              "disabling auto defrag");
 738                         break;
 739                 case Opt_recovery:
 740                         btrfs_warn(root->fs_info,
 741                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 742                 case Opt_usebackuproot:
 743                         btrfs_info(root->fs_info,
 744                                    "trying to use backup root at mount time");
 745                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 746                         break;
 747                 case Opt_skip_balance:
 748                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 749                         break;
 750 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 751                 case Opt_check_integrity_including_extent_data:
 752                         btrfs_info(root->fs_info,
 753                                    "enabling check integrity including extent data");
 754                         btrfs_set_opt(info->mount_opt,
 755                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 756                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 757                         break;
 758                 case Opt_check_integrity:
 759                         btrfs_info(root->fs_info, "enabling check integrity");
 760                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 761                         break;
 762                 case Opt_check_integrity_print_mask:
 763                         ret = match_int(&args[0], &intarg);
 764                         if (ret) {
 765                                 goto out;
 766                         } else if (intarg >= 0) {
 767                                 info->check_integrity_print_mask = intarg;
 768                                 btrfs_info(root->fs_info,
 769                                            "check_integrity_print_mask 0x%x",
 770                                            info->check_integrity_print_mask);
 771                         } else {
 772                                 ret = -EINVAL;
 773                                 goto out;
 774                         }
 775                         break;
 776 #else
 777                 case Opt_check_integrity_including_extent_data:
 778                 case Opt_check_integrity:
 779                 case Opt_check_integrity_print_mask:
 780                         btrfs_err(root->fs_info,
 781                                 "support for check_integrity* not compiled in!");
 782                         ret = -EINVAL;
 783                         goto out;
 784 #endif
 785                 case Opt_fatal_errors:
 786                         if (strcmp(args[0].from, "panic") == 0)
 787                                 btrfs_set_opt(info->mount_opt,
 788                                               PANIC_ON_FATAL_ERROR);
 789                         else if (strcmp(args[0].from, "bug") == 0)
 790                                 btrfs_clear_opt(info->mount_opt,
 791                                               PANIC_ON_FATAL_ERROR);
 792                         else {
 793                                 ret = -EINVAL;
 794                                 goto out;
 795                         }
 796                         break;
 797                 case Opt_commit_interval:
 798                         intarg = 0;
 799                         ret = match_int(&args[0], &intarg);
 800                         if (ret < 0) {
 801                                 btrfs_err(root->fs_info,
 802                                           "invalid commit interval");
 803                                 ret = -EINVAL;
 804                                 goto out;
 805                         }
 806                         if (intarg > 0) {
 807                                 if (intarg > 300) {
 808                                         btrfs_warn(root->fs_info,
 809                                                 "excessive commit interval %d",
 810                                                 intarg);
 811                                 }
 812                                 info->commit_interval = intarg;
 813                         } else {
 814                                 btrfs_info(root->fs_info,
 815                                            "using default commit interval %ds",
 816                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 817                                 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 818                         }
 819                         break;
 820 #ifdef CONFIG_BTRFS_DEBUG
 821                 case Opt_fragment_all:
 822                         btrfs_info(root->fs_info, "fragmenting all space");
 823                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 824                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 825                         break;
 826                 case Opt_fragment_metadata:
 827                         btrfs_info(root->fs_info, "fragmenting metadata");
 828                         btrfs_set_opt(info->mount_opt,
 829                                       FRAGMENT_METADATA);
 830                         break;
 831                 case Opt_fragment_data:
 832                         btrfs_info(root->fs_info, "fragmenting data");
 833                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 834                         break;
 835 #endif
 836                 case Opt_err:
 837                         btrfs_info(root->fs_info,
 838                                    "unrecognized mount option '%s'", p);
 839                         ret = -EINVAL;
 840                         goto out;
 841                 default:
 842                         break;
 843                 }
 844         }
 845 check:
 846         /*
 847          * Extra check for current option against current flag
 848          */
 849         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
 850                 btrfs_err(root->fs_info,
 851                           "nologreplay must be used with ro mount option");
 852                 ret = -EINVAL;
 853         }
 854 out:
 855         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
 856             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 857             !btrfs_test_opt(info, CLEAR_CACHE)) {
 858                 btrfs_err(root->fs_info, "cannot disable free space tree");
 859                 ret = -EINVAL;
 860
 861         }
 862         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 863                 btrfs_info(root->fs_info, "disk space caching is enabled");
 864         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 865                 btrfs_info(root->fs_info, "using free space tree");
 866         kfree(orig);
 867         return ret;
 868 }
 869
 870 /*
 871  * Parse mount options that are required early in the mount process.
 872  *
 873  * All other options will be parsed on much later in the mount process and
 874  * only when we need to allocate a new super block.
 875  */
 876 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 877                 void *holder, char **subvol_name, u64 *subvol_objectid,
 878                 struct btrfs_fs_devices **fs_devices)
 879 {
 880         substring_t args[MAX_OPT_ARGS];
 881         char *device_name, *opts, *orig, *p;
 882         char *num = NULL;
 883         int error = 0;
 884
 885         if (!options)
 886                 return 0;
 887
 888         /*
 889          * strsep changes the string, duplicate it because parse_options
 890          * gets called twice
 891          */
 892         opts = kstrdup(options, GFP_KERNEL);
 893         if (!opts)
 894                 return -ENOMEM;
 895         orig = opts;
 896
 897         while ((p = strsep(&opts, ",")) != NULL) {
 898                 int token;
 899                 if (!*p)
 900                         continue;
 901
 902                 token = match_token(p, tokens, args);
 903                 switch (token) {
 904                 case Opt_subvol:
 905                         kfree(*subvol_name);
 906                         *subvol_name = match_strdup(&args[0]);
 907                         if (!*subvol_name) {
 908                                 error = -ENOMEM;
 909                                 goto out;
 910                         }
 911                         break;
 912                 case Opt_subvolid:
 913                         num = match_strdup(&args[0]);
 914                         if (num) {
 915                                 *subvol_objectid = memparse(num, NULL);
 916                                 kfree(num);
 917                                 /* we want the original fs_tree */
 918                                 if (!*subvol_objectid)
 919                                         *subvol_objectid =
 920                                                 BTRFS_FS_TREE_OBJECTID;
 921                         } else {
 922                                 error = -EINVAL;
 923                                 goto out;
 924                         }
 925                         break;
 926                 case Opt_subvolrootid:
 927                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
 928                         break;
 929                 case Opt_device:
 930                         device_name = match_strdup(&args[0]);
 931                         if (!device_name) {
 932                                 error = -ENOMEM;
 933                                 goto out;
 934                         }
 935                         error = btrfs_scan_one_device(device_name,
 936                                         flags, holder, fs_devices);
 937                         kfree(device_name);
 938                         if (error)
 939                                 goto out;
 940                         break;
 941                 default:
 942                         break;
 943                 }
 944         }
 945
 946 out:
 947         kfree(orig);
 948         return error;
 949 }
 950
 951 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 952                                           u64 subvol_objectid)
 953 {
 954         struct btrfs_root *root = fs_info->tree_root;
 955         struct btrfs_root *fs_root;
 956         struct btrfs_root_ref *root_ref;
 957         struct btrfs_inode_ref *inode_ref;
 958         struct btrfs_key key;
 959         struct btrfs_path *path = NULL;
 960         char *name = NULL, *ptr;
 961         u64 dirid;
 962         int len;
 963         int ret;
 964
 965         path = btrfs_alloc_path();
 966         if (!path) {
 967                 ret = -ENOMEM;
 968                 goto err;
 969         }
 970         path->leave_spinning = 1;
 971
 972         name = kmalloc(PATH_MAX, GFP_NOFS);
 973         if (!name) {
 974                 ret = -ENOMEM;
 975                 goto err;
 976         }
 977         ptr = name + PATH_MAX - 1;
 978         ptr[0] = '\0';
 979
 980         /*
 981          * Walk up the subvolume trees in the tree of tree roots by root
 982          * backrefs until we hit the top-level subvolume.
 983          */
 984         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 985                 key.objectid = subvol_objectid;
 986                 key.type = BTRFS_ROOT_BACKREF_KEY;
 987                 key.offset = (u64)-1;
 988
 989                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 990                 if (ret < 0) {
 991                         goto err;
 992                 } else if (ret > 0) {
 993                         ret = btrfs_previous_item(root, path, subvol_objectid,
 994                                                   BTRFS_ROOT_BACKREF_KEY);
 995                         if (ret < 0) {
 996                                 goto err;
 997                         } else if (ret > 0) {
 998                                 ret = -ENOENT;
 999                                 goto err;
1000                         }
1001                 }
1002
1003                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1004                 subvol_objectid = key.offset;
1005
1006                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1007                                           struct btrfs_root_ref);
1008                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1009                 ptr -= len + 1;
1010                 if (ptr < name) {
1011                         ret = -ENAMETOOLONG;
1012                         goto err;
1013                 }
1014                 read_extent_buffer(path->nodes[0], ptr + 1,
1015                                    (unsigned long)(root_ref + 1), len);
1016                 ptr[0] = '/';
1017                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1018                 btrfs_release_path(path);
1019
1020                 key.objectid = subvol_objectid;
1021                 key.type = BTRFS_ROOT_ITEM_KEY;
1022                 key.offset = (u64)-1;
1023                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1024                 if (IS_ERR(fs_root)) {
1025                         ret = PTR_ERR(fs_root);
1026                         goto err;
1027                 }
1028
1029                 /*
1030                  * Walk up the filesystem tree by inode refs until we hit the
1031                  * root directory.
1032                  */
1033                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1034                         key.objectid = dirid;
1035                         key.type = BTRFS_INODE_REF_KEY;
1036                         key.offset = (u64)-1;
1037
1038                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1039                         if (ret < 0) {
1040                                 goto err;
1041                         } else if (ret > 0) {
1042                                 ret = btrfs_previous_item(fs_root, path, dirid,
1043                                                           BTRFS_INODE_REF_KEY);
1044                                 if (ret < 0) {
1045                                         goto err;
1046                                 } else if (ret > 0) {
1047                                         ret = -ENOENT;
1048                                         goto err;
1049                                 }
1050                         }
1051
1052                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1053                         dirid = key.offset;
1054
1055                         inode_ref = btrfs_item_ptr(path->nodes[0],
1056                                                    path->slots[0],
1057                                                    struct btrfs_inode_ref);
1058                         len = btrfs_inode_ref_name_len(path->nodes[0],
1059                                                        inode_ref);
1060                         ptr -= len + 1;
1061                         if (ptr < name) {
1062                                 ret = -ENAMETOOLONG;
1063                                 goto err;
1064                         }
1065                         read_extent_buffer(path->nodes[0], ptr + 1,
1066                                            (unsigned long)(inode_ref + 1), len);
1067                         ptr[0] = '/';
1068                         btrfs_release_path(path);
1069                 }
1070         }
1071
1072         btrfs_free_path(path);
1073         if (ptr == name + PATH_MAX - 1) {
1074                 name[0] = '/';
1075                 name[1] = '\0';
1076         } else {
1077                 memmove(name, ptr, name + PATH_MAX - ptr);
1078         }
1079         return name;
1080
1081 err:
1082         btrfs_free_path(path);
1083         kfree(name);
1084         return ERR_PTR(ret);
1085 }
1086
1087 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1088 {
1089         struct btrfs_root *root = fs_info->tree_root;
1090         struct btrfs_dir_item *di;
1091         struct btrfs_path *path;
1092         struct btrfs_key location;
1093         u64 dir_id;
1094
1095         path = btrfs_alloc_path();
1096         if (!path)
1097                 return -ENOMEM;
1098         path->leave_spinning = 1;
1099
1100         /*
1101          * Find the "default" dir item which points to the root item that we
1102          * will mount by default if we haven't been given a specific subvolume
1103          * to mount.
1104          */
1105         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1106         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1107         if (IS_ERR(di)) {
1108                 btrfs_free_path(path);
1109                 return PTR_ERR(di);
1110         }
1111         if (!di) {
1112                 /*
1113                  * Ok the default dir item isn't there.  This is weird since
1114                  * it's always been there, but don't freak out, just try and
1115                  * mount the top-level subvolume.
1116                  */
1117                 btrfs_free_path(path);
1118                 *objectid = BTRFS_FS_TREE_OBJECTID;
1119                 return 0;
1120         }
1121
1122         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1123         btrfs_free_path(path);
1124         *objectid = location.objectid;
1125         return 0;
1126 }
1127
1128 static int btrfs_fill_super(struct super_block *sb,
1129                             struct btrfs_fs_devices *fs_devices,
1130                             void *data, int silent)
1131 {
1132         struct inode *inode;
1133         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1134         struct btrfs_key key;
1135         int err;
1136
1137         sb->s_maxbytes = MAX_LFS_FILESIZE;
1138         sb->s_magic = BTRFS_SUPER_MAGIC;
1139         sb->s_op = &btrfs_super_ops;
1140         sb->s_d_op = &btrfs_dentry_operations;
1141         sb->s_export_op = &btrfs_export_ops;
1142         sb->s_xattr = btrfs_xattr_handlers;
1143         sb->s_time_gran = 1;
1144 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1145         sb->s_flags |= MS_POSIXACL;
1146 #endif
1147         sb->s_flags |= MS_I_VERSION;
1148         sb->s_iflags |= SB_I_CGROUPWB;
1149         err = open_ctree(sb, fs_devices, (char *)data);
1150         if (err) {
1151                 btrfs_err(fs_info, "open_ctree failed");
1152                 return err;
1153         }
1154
1155         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1156         key.type = BTRFS_INODE_ITEM_KEY;
1157         key.offset = 0;
1158         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1159         if (IS_ERR(inode)) {
1160                 err = PTR_ERR(inode);
1161                 goto fail_close;
1162         }
1163
1164         sb->s_root = d_make_root(inode);
1165         if (!sb->s_root) {
1166                 err = -ENOMEM;
1167                 goto fail_close;
1168         }
1169
1170         save_mount_options(sb, data);
1171         cleancache_init_fs(sb);
1172         sb->s_flags |= MS_ACTIVE;
1173         return 0;
1174
1175 fail_close:
1176         close_ctree(fs_info->tree_root);
1177         return err;
1178 }
1179
1180 int btrfs_sync_fs(struct super_block *sb, int wait)
1181 {
1182         struct btrfs_trans_handle *trans;
1183         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1184         struct btrfs_root *root = fs_info->tree_root;
1185
1186         trace_btrfs_sync_fs(fs_info, wait);
1187
1188         if (!wait) {
1189                 filemap_flush(fs_info->btree_inode->i_mapping);
1190                 return 0;
1191         }
1192
1193         btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
1194
1195         trans = btrfs_attach_transaction_barrier(root);
1196         if (IS_ERR(trans)) {
1197                 /* no transaction, don't bother */
1198                 if (PTR_ERR(trans) == -ENOENT) {
1199                         /*
1200                          * Exit unless we have some pending changes
1201                          * that need to go through commit
1202                          */
1203                         if (fs_info->pending_changes == 0)
1204                                 return 0;
1205                         /*
1206                          * A non-blocking test if the fs is frozen. We must not
1207                          * start a new transaction here otherwise a deadlock
1208                          * happens. The pending operations are delayed to the
1209                          * next commit after thawing.
1210                          */
1211                         if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1212                                 __sb_end_write(sb, SB_FREEZE_WRITE);
1213                         else
1214                                 return 0;
1215                         trans = btrfs_start_transaction(root, 0);
1216                 }
1217                 if (IS_ERR(trans))
1218                         return PTR_ERR(trans);
1219         }
1220         return btrfs_commit_transaction(trans, root);
1221 }
1222
1223 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1224 {
1225         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1226         struct btrfs_root *root = info->tree_root;
1227         char *compress_type;
1228         const char *subvol_name;
1229
1230         if (btrfs_test_opt(info, DEGRADED))
1231                 seq_puts(seq, ",degraded");
1232         if (btrfs_test_opt(info, NODATASUM))
1233                 seq_puts(seq, ",nodatasum");
1234         if (btrfs_test_opt(info, NODATACOW))
1235                 seq_puts(seq, ",nodatacow");
1236         if (btrfs_test_opt(info, NOBARRIER))
1237                 seq_puts(seq, ",nobarrier");
1238         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1239                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1240         if (info->alloc_start != 0)
1241                 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1242         if (info->thread_pool_size !=  min_t(unsigned long,
1243                                              num_online_cpus() + 2, 8))
1244                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1245         if (btrfs_test_opt(info, COMPRESS)) {
1246                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1247                         compress_type = "zlib";
1248                 else
1249                         compress_type = "lzo";
1250                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1251                         seq_printf(seq, ",compress-force=%s", compress_type);
1252                 else
1253                         seq_printf(seq, ",compress=%s", compress_type);
1254         }
1255         if (btrfs_test_opt(info, NOSSD))
1256                 seq_puts(seq, ",nossd");
1257         if (btrfs_test_opt(info, SSD_SPREAD))
1258                 seq_puts(seq, ",ssd_spread");
1259         else if (btrfs_test_opt(info, SSD))
1260                 seq_puts(seq, ",ssd");
1261         if (btrfs_test_opt(info, NOTREELOG))
1262                 seq_puts(seq, ",notreelog");
1263         if (btrfs_test_opt(info, NOLOGREPLAY))
1264                 seq_puts(seq, ",nologreplay");
1265         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1266                 seq_puts(seq, ",flushoncommit");
1267         if (btrfs_test_opt(info, DISCARD))
1268                 seq_puts(seq, ",discard");
1269         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1270                 seq_puts(seq, ",noacl");
1271         if (btrfs_test_opt(info, SPACE_CACHE))
1272                 seq_puts(seq, ",space_cache");
1273         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1274                 seq_puts(seq, ",space_cache=v2");
1275         else
1276                 seq_puts(seq, ",nospace_cache");
1277         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1278                 seq_puts(seq, ",rescan_uuid_tree");
1279         if (btrfs_test_opt(info, CLEAR_CACHE))
1280                 seq_puts(seq, ",clear_cache");
1281         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1282                 seq_puts(seq, ",user_subvol_rm_allowed");
1283         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1284                 seq_puts(seq, ",enospc_debug");
1285         if (btrfs_test_opt(info, AUTO_DEFRAG))
1286                 seq_puts(seq, ",autodefrag");
1287         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1288                 seq_puts(seq, ",inode_cache");
1289         if (btrfs_test_opt(info, SKIP_BALANCE))
1290                 seq_puts(seq, ",skip_balance");
1291 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1292         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1293                 seq_puts(seq, ",check_int_data");
1294         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1295                 seq_puts(seq, ",check_int");
1296         if (info->check_integrity_print_mask)
1297                 seq_printf(seq, ",check_int_print_mask=%d",
1298                                 info->check_integrity_print_mask);
1299 #endif
1300         if (info->metadata_ratio)
1301                 seq_printf(seq, ",metadata_ratio=%d",
1302                                 info->metadata_ratio);
1303         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1304                 seq_puts(seq, ",fatal_errors=panic");
1305         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1306                 seq_printf(seq, ",commit=%d", info->commit_interval);
1307 #ifdef CONFIG_BTRFS_DEBUG
1308         if (btrfs_test_opt(info, FRAGMENT_DATA))
1309                 seq_puts(seq, ",fragment=data");
1310         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1311                 seq_puts(seq, ",fragment=metadata");
1312 #endif
1313         seq_printf(seq, ",subvolid=%llu",
1314                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1315         subvol_name = btrfs_get_subvol_name_from_objectid(info,
1316                         BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1317         if (!IS_ERR(subvol_name)) {
1318                 seq_puts(seq, ",subvol=");
1319                 seq_escape(seq, subvol_name, " \t\n\\");
1320                 kfree(subvol_name);
1321         }
1322         return 0;
1323 }
1324
1325 static int btrfs_test_super(struct super_block *s, void *data)
1326 {
1327         struct btrfs_fs_info *p = data;
1328         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1329
1330         return fs_info->fs_devices == p->fs_devices;
1331 }
1332
1333 static int btrfs_set_super(struct super_block *s, void *data)
1334 {
1335         int err = set_anon_super(s, data);
1336         if (!err)
1337                 s->s_fs_info = data;
1338         return err;
1339 }
1340
1341 /*
1342  * subvolumes are identified by ino 256
1343  */
1344 static inline int is_subvolume_inode(struct inode *inode)
1345 {
1346         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1347                 return 1;
1348         return 0;
1349 }
1350
1351 /*
1352  * This will add subvolid=0 to the argument string while removing any subvol=
1353  * and subvolid= arguments to make sure we get the top-level root for path
1354  * walking to the subvol we want.
1355  */
1356 static char *setup_root_args(char *args)
1357 {
1358         char *buf, *dst, *sep;
1359
1360         if (!args)
1361                 return kstrdup("subvolid=0", GFP_NOFS);
1362
1363         /* The worst case is that we add ",subvolid=0" to the end. */
1364         buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1365         if (!buf)
1366                 return NULL;
1367
1368         while (1) {
1369                 sep = strchrnul(args, ',');
1370                 if (!strstarts(args, "subvol=") &&
1371                     !strstarts(args, "subvolid=")) {
1372                         memcpy(dst, args, sep - args);
1373                         dst += sep - args;
1374                         *dst++ = ',';
1375                 }
1376                 if (*sep)
1377                         args = sep + 1;
1378                 else
1379                         break;
1380         }
1381         strcpy(dst, "subvolid=0");
1382
1383         return buf;
1384 }
1385
1386 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1387                                    int flags, const char *device_name,
1388                                    char *data)
1389 {
1390         struct dentry *root;
1391         struct vfsmount *mnt = NULL;
1392         char *newargs;
1393         int ret;
1394
1395         newargs = setup_root_args(data);
1396         if (!newargs) {
1397                 root = ERR_PTR(-ENOMEM);
1398                 goto out;
1399         }
1400
1401         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1402         if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1403                 if (flags & MS_RDONLY) {
1404                         mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1405                                              device_name, newargs);
1406                 } else {
1407                         mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1408                                              device_name, newargs);
1409                         if (IS_ERR(mnt)) {
1410                                 root = ERR_CAST(mnt);
1411                                 mnt = NULL;
1412                                 goto out;
1413                         }
1414
1415                         down_write(&mnt->mnt_sb->s_umount);
1416                         ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1417                         up_write(&mnt->mnt_sb->s_umount);
1418                         if (ret < 0) {
1419                                 root = ERR_PTR(ret);
1420                                 goto out;
1421                         }
1422                 }
1423         }
1424         if (IS_ERR(mnt)) {
1425                 root = ERR_CAST(mnt);
1426                 mnt = NULL;
1427                 goto out;
1428         }
1429
1430         if (!subvol_name) {
1431                 if (!subvol_objectid) {
1432                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1433                                                           &subvol_objectid);
1434                         if (ret) {
1435                                 root = ERR_PTR(ret);
1436                                 goto out;
1437                         }
1438                 }
1439                 subvol_name = btrfs_get_subvol_name_from_objectid(
1440                                         btrfs_sb(mnt->mnt_sb), subvol_objectid);
1441                 if (IS_ERR(subvol_name)) {
1442                         root = ERR_CAST(subvol_name);
1443                         subvol_name = NULL;
1444                         goto out;
1445                 }
1446
1447         }
1448
1449         root = mount_subtree(mnt, subvol_name);
1450         /* mount_subtree() drops our reference on the vfsmount. */
1451         mnt = NULL;
1452
1453         if (!IS_ERR(root)) {
1454                 struct super_block *s = root->d_sb;
1455                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1456                 struct inode *root_inode = d_inode(root);
1457                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1458
1459                 ret = 0;
1460                 if (!is_subvolume_inode(root_inode)) {
1461                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1462                                subvol_name);
1463                         ret = -EINVAL;
1464                 }
1465                 if (subvol_objectid && root_objectid != subvol_objectid) {
1466                         /*
1467                          * This will also catch a race condition where a
1468                          * subvolume which was passed by ID is renamed and
1469                          * another subvolume is renamed over the old location.
1470                          */
1471                         btrfs_err(fs_info,
1472                                   "subvol '%s' does not match subvolid %llu",
1473                                   subvol_name, subvol_objectid);
1474                         ret = -EINVAL;
1475                 }
1476                 if (ret) {
1477                         dput(root);
1478                         root = ERR_PTR(ret);
1479                         deactivate_locked_super(s);
1480                 }
1481         }
1482
1483 out:
1484         mntput(mnt);
1485         kfree(newargs);
1486         kfree(subvol_name);
1487         return root;
1488 }
1489
1490 static int parse_security_options(char *orig_opts,
1491                                   struct security_mnt_opts *sec_opts)
1492 {
1493         char *secdata = NULL;
1494         int ret = 0;
1495
1496         secdata = alloc_secdata();
1497         if (!secdata)
1498                 return -ENOMEM;
1499         ret = security_sb_copy_data(orig_opts, secdata);
1500         if (ret) {
1501                 free_secdata(secdata);
1502                 return ret;
1503         }
1504         ret = security_sb_parse_opts_str(secdata, sec_opts);
1505         free_secdata(secdata);
1506         return ret;
1507 }
1508
1509 static int setup_security_options(struct btrfs_fs_info *fs_info,
1510                                   struct super_block *sb,
1511                                   struct security_mnt_opts *sec_opts)
1512 {
1513         int ret = 0;
1514
1515         /*
1516          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1517          * is valid.
1518          */
1519         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1520         if (ret)
1521                 return ret;
1522
1523 #ifdef CONFIG_SECURITY
1524         if (!fs_info->security_opts.num_mnt_opts) {
1525                 /* first time security setup, copy sec_opts to fs_info */
1526                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1527         } else {
1528                 /*
1529                  * Since SELinux (the only one supporting security_mnt_opts)
1530                  * does NOT support changing context during remount/mount of
1531                  * the same sb, this must be the same or part of the same
1532                  * security options, just free it.
1533                  */
1534                 security_free_mnt_opts(sec_opts);
1535         }
1536 #endif
1537         return ret;
1538 }
1539
1540 /*
1541  * Find a superblock for the given device / mount point.
1542  *
1543  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1544  *        for multiple device setup.  Make sure to keep it in sync.
1545  */
1546 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1547                 const char *device_name, void *data)
1548 {
1549         struct block_device *bdev = NULL;
1550         struct super_block *s;
1551         struct btrfs_fs_devices *fs_devices = NULL;
1552         struct btrfs_fs_info *fs_info = NULL;
1553         struct security_mnt_opts new_sec_opts;
1554         fmode_t mode = FMODE_READ;
1555         char *subvol_name = NULL;
1556         u64 subvol_objectid = 0;
1557         int error = 0;
1558
1559         if (!(flags & MS_RDONLY))
1560                 mode |= FMODE_WRITE;
1561
1562         error = btrfs_parse_early_options(data, mode, fs_type,
1563                                           &subvol_name, &subvol_objectid,
1564                                           &fs_devices);
1565         if (error) {
1566                 kfree(subvol_name);
1567                 return ERR_PTR(error);
1568         }
1569
1570         if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1571                 /* mount_subvol() will free subvol_name. */
1572                 return mount_subvol(subvol_name, subvol_objectid, flags,
1573                                     device_name, data);
1574         }
1575
1576         security_init_mnt_opts(&new_sec_opts);
1577         if (data) {
1578                 error = parse_security_options(data, &new_sec_opts);
1579                 if (error)
1580                         return ERR_PTR(error);
1581         }
1582
1583         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1584         if (error)
1585                 goto error_sec_opts;
1586
1587         /*
1588          * Setup a dummy root and fs_info for test/set super.  This is because
1589          * we don't actually fill this stuff out until open_ctree, but we need
1590          * it for searching for existing supers, so this lets us do that and
1591          * then open_ctree will properly initialize everything later.
1592          */
1593         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1594         if (!fs_info) {
1595                 error = -ENOMEM;
1596                 goto error_sec_opts;
1597         }
1598
1599         fs_info->fs_devices = fs_devices;
1600
1601         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1602         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1603         security_init_mnt_opts(&fs_info->security_opts);
1604         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1605                 error = -ENOMEM;
1606                 goto error_fs_info;
1607         }
1608
1609         error = btrfs_open_devices(fs_devices, mode, fs_type);
1610         if (error)
1611                 goto error_fs_info;
1612
1613         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1614                 error = -EACCES;
1615                 goto error_close_devices;
1616         }
1617
1618         bdev = fs_devices->latest_bdev;
1619         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1620                  fs_info);
1621         if (IS_ERR(s)) {
1622                 error = PTR_ERR(s);
1623                 goto error_close_devices;
1624         }
1625
1626         if (s->s_root) {
1627                 btrfs_close_devices(fs_devices);
1628                 free_fs_info(fs_info);
1629                 if ((flags ^ s->s_flags) & MS_RDONLY)
1630                         error = -EBUSY;
1631         } else {
1632                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1633                 btrfs_sb(s)->bdev_holder = fs_type;
1634                 error = btrfs_fill_super(s, fs_devices, data,
1635                                          flags & MS_SILENT ? 1 : 0);
1636         }
1637         if (error) {
1638                 deactivate_locked_super(s);
1639                 goto error_sec_opts;
1640         }
1641
1642         fs_info = btrfs_sb(s);
1643         error = setup_security_options(fs_info, s, &new_sec_opts);
1644         if (error) {
1645                 deactivate_locked_super(s);
1646                 goto error_sec_opts;
1647         }
1648
1649         return dget(s->s_root);
1650
1651 error_close_devices:
1652         btrfs_close_devices(fs_devices);
1653 error_fs_info:
1654         free_fs_info(fs_info);
1655 error_sec_opts:
1656         security_free_mnt_opts(&new_sec_opts);
1657         return ERR_PTR(error);
1658 }
1659
1660 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1661                                      int new_pool_size, int old_pool_size)
1662 {
1663         if (new_pool_size == old_pool_size)
1664                 return;
1665
1666         fs_info->thread_pool_size = new_pool_size;
1667
1668         btrfs_info(fs_info, "resize thread pool %d -> %d",
1669                old_pool_size, new_pool_size);
1670
1671         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1672         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1673         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1674         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1675         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1676         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1677         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1678                                 new_pool_size);
1679         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1680         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1681         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1682         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1683         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1684                                 new_pool_size);
1685 }
1686
1687 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1688 {
1689         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1690 }
1691
1692 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1693                                        unsigned long old_opts, int flags)
1694 {
1695         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1696             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1697              (flags & MS_RDONLY))) {
1698                 /* wait for any defraggers to finish */
1699                 wait_event(fs_info->transaction_wait,
1700                            (atomic_read(&fs_info->defrag_running) == 0));
1701                 if (flags & MS_RDONLY)
1702                         sync_filesystem(fs_info->sb);
1703         }
1704 }
1705
1706 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1707                                          unsigned long old_opts)
1708 {
1709         /*
1710          * We need to cleanup all defragable inodes if the autodefragment is
1711          * close or the filesystem is read only.
1712          */
1713         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1714             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1715              (fs_info->sb->s_flags & MS_RDONLY))) {
1716                 btrfs_cleanup_defrag_inodes(fs_info);
1717         }
1718
1719         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1720 }
1721
1722 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1723 {
1724         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1725         struct btrfs_root *root = fs_info->tree_root;
1726         unsigned old_flags = sb->s_flags;
1727         unsigned long old_opts = fs_info->mount_opt;
1728         unsigned long old_compress_type = fs_info->compress_type;
1729         u64 old_max_inline = fs_info->max_inline;
1730         u64 old_alloc_start = fs_info->alloc_start;
1731         int old_thread_pool_size = fs_info->thread_pool_size;
1732         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1733         int ret;
1734
1735         sync_filesystem(sb);
1736         btrfs_remount_prepare(fs_info);
1737
1738         if (data) {
1739                 struct security_mnt_opts new_sec_opts;
1740
1741                 security_init_mnt_opts(&new_sec_opts);
1742                 ret = parse_security_options(data, &new_sec_opts);
1743                 if (ret)
1744                         goto restore;
1745                 ret = setup_security_options(fs_info, sb,
1746                                              &new_sec_opts);
1747                 if (ret) {
1748                         security_free_mnt_opts(&new_sec_opts);
1749                         goto restore;
1750                 }
1751         }
1752
1753         ret = btrfs_parse_options(root, data, *flags);
1754         if (ret) {
1755                 ret = -EINVAL;
1756                 goto restore;
1757         }
1758
1759         btrfs_remount_begin(fs_info, old_opts, *flags);
1760         btrfs_resize_thread_pool(fs_info,
1761                 fs_info->thread_pool_size, old_thread_pool_size);
1762
1763         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1764                 goto out;
1765
1766         if (*flags & MS_RDONLY) {
1767                 /*
1768                  * this also happens on 'umount -rf' or on shutdown, when
1769                  * the filesystem is busy.
1770                  */
1771                 cancel_work_sync(&fs_info->async_reclaim_work);
1772
1773                 /* wait for the uuid_scan task to finish */
1774                 down(&fs_info->uuid_tree_rescan_sem);
1775                 /* avoid complains from lockdep et al. */
1776                 up(&fs_info->uuid_tree_rescan_sem);
1777
1778                 sb->s_flags |= MS_RDONLY;
1779
1780                 /*
1781                  * Setting MS_RDONLY will put the cleaner thread to
1782                  * sleep at the next loop if it's already active.
1783                  * If it's already asleep, we'll leave unused block
1784                  * groups on disk until we're mounted read-write again
1785                  * unless we clean them up here.
1786                  */
1787                 btrfs_delete_unused_bgs(fs_info);
1788
1789                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1790                 btrfs_scrub_cancel(fs_info);
1791                 btrfs_pause_balance(fs_info);
1792
1793                 ret = btrfs_commit_super(root);
1794                 if (ret)
1795                         goto restore;
1796         } else {
1797                 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1798                         btrfs_err(fs_info,
1799                                 "Remounting read-write after error is not allowed");
1800                         ret = -EINVAL;
1801                         goto restore;
1802                 }
1803                 if (fs_info->fs_devices->rw_devices == 0) {
1804                         ret = -EACCES;
1805                         goto restore;
1806                 }
1807
1808                 if (fs_info->fs_devices->missing_devices >
1809                      fs_info->num_tolerated_disk_barrier_failures &&
1810                     !(*flags & MS_RDONLY)) {
1811                         btrfs_warn(fs_info,
1812                                 "too many missing devices, writeable remount is not allowed");
1813                         ret = -EACCES;
1814                         goto restore;
1815                 }
1816
1817                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1818                         btrfs_warn(fs_info,
1819                 "mount required to replay tree-log, cannot remount read-write");
1820                         ret = -EINVAL;
1821                         goto restore;
1822                 }
1823
1824                 ret = btrfs_cleanup_fs_roots(fs_info);
1825                 if (ret)
1826                         goto restore;
1827
1828                 /* recover relocation */
1829                 mutex_lock(&fs_info->cleaner_mutex);
1830                 ret = btrfs_recover_relocation(root);
1831                 mutex_unlock(&fs_info->cleaner_mutex);
1832                 if (ret)
1833                         goto restore;
1834
1835                 ret = btrfs_resume_balance_async(fs_info);
1836                 if (ret)
1837                         goto restore;
1838
1839                 ret = btrfs_resume_dev_replace_async(fs_info);
1840                 if (ret) {
1841                         btrfs_warn(fs_info, "failed to resume dev_replace");
1842                         goto restore;
1843                 }
1844
1845                 btrfs_qgroup_rescan_resume(fs_info);
1846
1847                 if (!fs_info->uuid_root) {
1848                         btrfs_info(fs_info, "creating UUID tree");
1849                         ret = btrfs_create_uuid_tree(fs_info);
1850                         if (ret) {
1851                                 btrfs_warn(fs_info,
1852                                            "failed to create the UUID tree %d",
1853                                            ret);
1854                                 goto restore;
1855                         }
1856                 }
1857                 sb->s_flags &= ~MS_RDONLY;
1858
1859                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1860         }
1861 out:
1862         wake_up_process(fs_info->transaction_kthread);
1863         btrfs_remount_cleanup(fs_info, old_opts);
1864         return 0;
1865
1866 restore:
1867         /* We've hit an error - don't reset MS_RDONLY */
1868         if (sb->s_flags & MS_RDONLY)
1869                 old_flags |= MS_RDONLY;
1870         sb->s_flags = old_flags;
1871         fs_info->mount_opt = old_opts;
1872         fs_info->compress_type = old_compress_type;
1873         fs_info->max_inline = old_max_inline;
1874         mutex_lock(&fs_info->chunk_mutex);
1875         fs_info->alloc_start = old_alloc_start;
1876         mutex_unlock(&fs_info->chunk_mutex);
1877         btrfs_resize_thread_pool(fs_info,
1878                 old_thread_pool_size, fs_info->thread_pool_size);
1879         fs_info->metadata_ratio = old_metadata_ratio;
1880         btrfs_remount_cleanup(fs_info, old_opts);
1881         return ret;
1882 }
1883
1884 /* Used to sort the devices by max_avail(descending sort) */
1885 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1886                                        const void *dev_info2)
1887 {
1888         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1889             ((struct btrfs_device_info *)dev_info2)->max_avail)
1890                 return -1;
1891         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1892                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1893                 return 1;
1894         else
1895         return 0;
1896 }
1897
1898 /*
1899  * sort the devices by max_avail, in which max free extent size of each device
1900  * is stored.(Descending Sort)
1901  */
1902 static inline void btrfs_descending_sort_devices(
1903                                         struct btrfs_device_info *devices,
1904                                         size_t nr_devices)
1905 {
1906         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1907              btrfs_cmp_device_free_bytes, NULL);
1908 }
1909
1910 /*
1911  * The helper to calc the free space on the devices that can be used to store
1912  * file data.
1913  */
1914 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1915 {
1916         struct btrfs_fs_info *fs_info = root->fs_info;
1917         struct btrfs_device_info *devices_info;
1918         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1919         struct btrfs_device *device;
1920         u64 skip_space;
1921         u64 type;
1922         u64 avail_space;
1923         u64 used_space;
1924         u64 min_stripe_size;
1925         int min_stripes = 1, num_stripes = 1;
1926         int i = 0, nr_devices;
1927         int ret;
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_NOFS);
1946         if (!devices_info)
1947                 return -ENOMEM;
1948
1949         /* calc min stripe number for data space allocation */
1950         type = btrfs_get_alloc_profile(root, 1);
1951         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1952                 min_stripes = 2;
1953                 num_stripes = nr_devices;
1954         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1955                 min_stripes = 2;
1956                 num_stripes = 2;
1957         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1958                 min_stripes = 4;
1959                 num_stripes = 4;
1960         }
1961
1962         if (type & BTRFS_BLOCK_GROUP_DUP)
1963                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1964         else
1965                 min_stripe_size = BTRFS_STRIPE_LEN;
1966
1967         if (fs_info->alloc_start)
1968                 mutex_lock(&fs_devices->device_list_mutex);
1969         rcu_read_lock();
1970         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1971                 if (!device->in_fs_metadata || !device->bdev ||
1972                     device->is_tgtdev_for_dev_replace)
1973                         continue;
1974
1975                 if (i >= nr_devices)
1976                         break;
1977
1978                 avail_space = device->total_bytes - device->bytes_used;
1979
1980                 /* align with stripe_len */
1981                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1982                 avail_space *= BTRFS_STRIPE_LEN;
1983
1984                 /*
1985                  * In order to avoid overwriting the superblock on the drive,
1986                  * btrfs starts at an offset of at least 1MB when doing chunk
1987                  * allocation.
1988                  */
1989                 skip_space = SZ_1M;
1990
1991                 /* user can set the offset in fs_info->alloc_start. */
1992                 if (fs_info->alloc_start &&
1993                     fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1994                     device->total_bytes) {
1995                         rcu_read_unlock();
1996                         skip_space = max(fs_info->alloc_start, skip_space);
1997
1998                         /*
1999                          * btrfs can not use the free space in
2000                          * [0, skip_space - 1], we must subtract it from the
2001                          * total. In order to implement it, we account the used
2002                          * space in this range first.
2003                          */
2004                         ret = btrfs_account_dev_extents_size(device, 0,
2005                                                              skip_space - 1,
2006                                                              &used_space);
2007                         if (ret) {
2008                                 kfree(devices_info);
2009                                 mutex_unlock(&fs_devices->device_list_mutex);
2010                                 return ret;
2011                         }
2012
2013                         rcu_read_lock();
2014
2015                         /* calc the free space in [0, skip_space - 1] */
2016                         skip_space -= used_space;
2017                 }
2018
2019                 /*
2020                  * we can use the free space in [0, skip_space - 1], subtract
2021                  * it from the total.
2022                  */
2023                 if (avail_space && avail_space >= skip_space)
2024                         avail_space -= skip_space;
2025                 else
2026                         avail_space = 0;
2027
2028                 if (avail_space < min_stripe_size)
2029                         continue;
2030
2031                 devices_info[i].dev = device;
2032                 devices_info[i].max_avail = avail_space;
2033
2034                 i++;
2035         }
2036         rcu_read_unlock();
2037         if (fs_info->alloc_start)
2038                 mutex_unlock(&fs_devices->device_list_mutex);
2039
2040         nr_devices = i;
2041
2042         btrfs_descending_sort_devices(devices_info, nr_devices);
2043
2044         i = nr_devices - 1;
2045         avail_space = 0;
2046         while (nr_devices >= min_stripes) {
2047                 if (num_stripes > nr_devices)
2048                         num_stripes = nr_devices;
2049
2050                 if (devices_info[i].max_avail >= min_stripe_size) {
2051                         int j;
2052                         u64 alloc_size;
2053
2054                         avail_space += devices_info[i].max_avail * num_stripes;
2055                         alloc_size = devices_info[i].max_avail;
2056                         for (j = i + 1 - num_stripes; j <= i; j++)
2057                                 devices_info[j].max_avail -= alloc_size;
2058                 }
2059                 i--;
2060                 nr_devices--;
2061         }
2062
2063         kfree(devices_info);
2064         *free_bytes = avail_space;
2065         return 0;
2066 }
2067
2068 /*
2069  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2070  *
2071  * If there's a redundant raid level at DATA block groups, use the respective
2072  * multiplier to scale the sizes.
2073  *
2074  * Unused device space usage is based on simulating the chunk allocator
2075  * algorithm that respects the device sizes, order of allocations and the
2076  * 'alloc_start' value, this is a close approximation of the actual use but
2077  * there are other factors that may change the result (like a new metadata
2078  * chunk).
2079  *
2080  * If metadata is exhausted, f_bavail will be 0.
2081  */
2082 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2083 {
2084         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2085         struct btrfs_super_block *disk_super = fs_info->super_copy;
2086         struct list_head *head = &fs_info->space_info;
2087         struct btrfs_space_info *found;
2088         u64 total_used = 0;
2089         u64 total_free_data = 0;
2090         u64 total_free_meta = 0;
2091         int bits = dentry->d_sb->s_blocksize_bits;
2092         __be32 *fsid = (__be32 *)fs_info->fsid;
2093         unsigned factor = 1;
2094         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2095         int ret;
2096         u64 thresh = 0;
2097         int mixed = 0;
2098
2099         /*
2100          * holding chunk_mutex to avoid allocating new chunks, holding
2101          * device_list_mutex to avoid the device being removed
2102          */
2103         rcu_read_lock();
2104         list_for_each_entry_rcu(found, head, list) {
2105                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2106                         int i;
2107
2108                         total_free_data += found->disk_total - found->disk_used;
2109                         total_free_data -=
2110                                 btrfs_account_ro_block_groups_free_space(found);
2111
2112                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2113                                 if (!list_empty(&found->block_groups[i])) {
2114                                         switch (i) {
2115                                         case BTRFS_RAID_DUP:
2116                                         case BTRFS_RAID_RAID1:
2117                                         case BTRFS_RAID_RAID10:
2118                                                 factor = 2;
2119                                         }
2120                                 }
2121                         }
2122                 }
2123
2124                 /*
2125                  * Metadata in mixed block goup profiles are accounted in data
2126                  */
2127                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2128                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2129                                 mixed = 1;
2130                         else
2131                                 total_free_meta += found->disk_total -
2132                                         found->disk_used;
2133                 }
2134
2135                 total_used += found->disk_used;
2136         }
2137
2138         rcu_read_unlock();
2139
2140         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2141         buf->f_blocks >>= bits;
2142         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2143
2144         /* Account global block reserve as used, it's in logical size already */
2145         spin_lock(&block_rsv->lock);
2146         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2147         if (buf->f_bfree >= block_rsv->size >> bits)
2148                 buf->f_bfree -= block_rsv->size >> bits;
2149         else
2150                 buf->f_bfree = 0;
2151         spin_unlock(&block_rsv->lock);
2152
2153         buf->f_bavail = div_u64(total_free_data, factor);
2154         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2155         if (ret)
2156                 return ret;
2157         buf->f_bavail += div_u64(total_free_data, factor);
2158         buf->f_bavail = buf->f_bavail >> bits;
2159
2160         /*
2161          * We calculate the remaining metadata space minus global reserve. If
2162          * this is (supposedly) smaller than zero, there's no space. But this
2163          * does not hold in practice, the exhausted state happens where's still
2164          * some positive delta. So we apply some guesswork and compare the
2165          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2166          *
2167          * We probably cannot calculate the exact threshold value because this
2168          * depends on the internal reservations requested by various
2169          * operations, so some operations that consume a few metadata will
2170          * succeed even if the Avail is zero. But this is better than the other
2171          * way around.
2172          */
2173         thresh = 4 * 1024 * 1024;
2174
2175         /*
2176          * We only want to claim there's no available space if we can no longer
2177          * allocate chunks for our metadata profile and our global reserve will
2178          * not fit in the free metadata space.  If we aren't ->full then we
2179          * still can allocate chunks and thus are fine using the currently
2180          * calculated f_bavail.
2181          */
2182         if (!mixed && block_rsv->space_info->full &&
2183             total_free_meta - thresh < block_rsv->size)
2184                 buf->f_bavail = 0;
2185
2186         buf->f_type = BTRFS_SUPER_MAGIC;
2187         buf->f_bsize = dentry->d_sb->s_blocksize;
2188         buf->f_namelen = BTRFS_NAME_LEN;
2189
2190         /* We treat it as constant endianness (it doesn't matter _which_)
2191            because we want the fsid to come out the same whether mounted
2192            on a big-endian or little-endian host */
2193         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2194         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2195         /* Mask in the root object ID too, to disambiguate subvols */
2196         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2197         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2198
2199         return 0;
2200 }
2201
2202 static void btrfs_kill_super(struct super_block *sb)
2203 {
2204         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2205         kill_anon_super(sb);
2206         free_fs_info(fs_info);
2207 }
2208
2209 static struct file_system_type btrfs_fs_type = {
2210         .owner          = THIS_MODULE,
2211         .name           = "btrfs",
2212         .mount          = btrfs_mount,
2213         .kill_sb        = btrfs_kill_super,
2214         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2215 };
2216 MODULE_ALIAS_FS("btrfs");
2217
2218 static int btrfs_control_open(struct inode *inode, struct file *file)
2219 {
2220         /*
2221          * The control file's private_data is used to hold the
2222          * transaction when it is started and is used to keep
2223          * track of whether a transaction is already in progress.
2224          */
2225         file->private_data = NULL;
2226         return 0;
2227 }
2228
2229 /*
2230  * used by btrfsctl to scan devices when no FS is mounted
2231  */
2232 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2233                                 unsigned long arg)
2234 {
2235         struct btrfs_ioctl_vol_args *vol;
2236         struct btrfs_fs_devices *fs_devices;
2237         int ret = -ENOTTY;
2238
2239         if (!capable(CAP_SYS_ADMIN))
2240                 return -EPERM;
2241
2242         vol = memdup_user((void __user *)arg, sizeof(*vol));
2243         if (IS_ERR(vol))
2244                 return PTR_ERR(vol);
2245         vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2246
2247         switch (cmd) {
2248         case BTRFS_IOC_SCAN_DEV:
2249                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2250                                             &btrfs_fs_type, &fs_devices);
2251                 break;
2252         case BTRFS_IOC_DEVICES_READY:
2253                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2254                                             &btrfs_fs_type, &fs_devices);
2255                 if (ret)
2256                         break;
2257                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2258                 break;
2259         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2260                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2261                 break;
2262         }
2263
2264         kfree(vol);
2265         return ret;
2266 }
2267
2268 static int btrfs_freeze(struct super_block *sb)
2269 {
2270         struct btrfs_trans_handle *trans;
2271         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2272
2273         root->fs_info->fs_frozen = 1;
2274         /*
2275          * We don't need a barrier here, we'll wait for any transaction that
2276          * could be in progress on other threads (and do delayed iputs that
2277          * we want to avoid on a frozen filesystem), or do the commit
2278          * ourselves.
2279          */
2280         trans = btrfs_attach_transaction_barrier(root);
2281         if (IS_ERR(trans)) {
2282                 /* no transaction, don't bother */
2283                 if (PTR_ERR(trans) == -ENOENT)
2284                         return 0;
2285                 return PTR_ERR(trans);
2286         }
2287         return btrfs_commit_transaction(trans, root);
2288 }
2289
2290 static int btrfs_unfreeze(struct super_block *sb)
2291 {
2292         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2293
2294         root->fs_info->fs_frozen = 0;
2295         return 0;
2296 }
2297
2298 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2299 {
2300         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2301         struct btrfs_fs_devices *cur_devices;
2302         struct btrfs_device *dev, *first_dev = NULL;
2303         struct list_head *head;
2304         struct rcu_string *name;
2305
2306         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2307         cur_devices = fs_info->fs_devices;
2308         while (cur_devices) {
2309                 head = &cur_devices->devices;
2310                 list_for_each_entry(dev, head, dev_list) {
2311                         if (dev->missing)
2312                                 continue;
2313                         if (!dev->name)
2314                                 continue;
2315                         if (!first_dev || dev->devid < first_dev->devid)
2316                                 first_dev = dev;
2317                 }
2318                 cur_devices = cur_devices->seed;
2319         }
2320
2321         if (first_dev) {
2322                 rcu_read_lock();
2323                 name = rcu_dereference(first_dev->name);
2324                 seq_escape(m, name->str, " \t\n\\");
2325                 rcu_read_unlock();
2326         } else {
2327                 WARN_ON(1);
2328         }
2329         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2330         return 0;
2331 }
2332
2333 static const struct super_operations btrfs_super_ops = {
2334         .drop_inode     = btrfs_drop_inode,
2335         .evict_inode    = btrfs_evict_inode,
2336         .put_super      = btrfs_put_super,
2337         .sync_fs        = btrfs_sync_fs,
2338         .show_options   = btrfs_show_options,
2339         .show_devname   = btrfs_show_devname,
2340         .write_inode    = btrfs_write_inode,
2341         .alloc_inode    = btrfs_alloc_inode,
2342         .destroy_inode  = btrfs_destroy_inode,
2343         .statfs         = btrfs_statfs,
2344         .remount_fs     = btrfs_remount,
2345         .freeze_fs      = btrfs_freeze,
2346         .unfreeze_fs    = btrfs_unfreeze,
2347 };
2348
2349 static const struct file_operations btrfs_ctl_fops = {
2350         .open = btrfs_control_open,
2351         .unlocked_ioctl  = btrfs_control_ioctl,
2352         .compat_ioctl = btrfs_control_ioctl,
2353         .owner   = THIS_MODULE,
2354         .llseek = noop_llseek,
2355 };
2356
2357 static struct miscdevice btrfs_misc = {
2358         .minor          = BTRFS_MINOR,
2359         .name           = "btrfs-control",
2360         .fops           = &btrfs_ctl_fops
2361 };
2362
2363 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2364 MODULE_ALIAS("devname:btrfs-control");
2365
2366 static int btrfs_interface_init(void)
2367 {
2368         return misc_register(&btrfs_misc);
2369 }
2370
2371 static void btrfs_interface_exit(void)
2372 {
2373         misc_deregister(&btrfs_misc);
2374 }
2375
2376 static void btrfs_print_mod_info(void)
2377 {
2378         pr_info("Btrfs loaded, crc32c=%s"
2379 #ifdef CONFIG_BTRFS_DEBUG
2380                         ", debug=on"
2381 #endif
2382 #ifdef CONFIG_BTRFS_ASSERT
2383                         ", assert=on"
2384 #endif
2385 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2386                         ", integrity-checker=on"
2387 #endif
2388                         "\n",
2389                         btrfs_crc32c_impl());
2390 }
2391
2392 static int __init init_btrfs_fs(void)
2393 {
2394         int err;
2395
2396         err = btrfs_hash_init();
2397         if (err)
2398                 return err;
2399
2400         btrfs_props_init();
2401
2402         err = btrfs_init_sysfs();
2403         if (err)
2404                 goto free_hash;
2405
2406         btrfs_init_compress();
2407
2408         err = btrfs_init_cachep();
2409         if (err)
2410                 goto free_compress;
2411
2412         err = extent_io_init();
2413         if (err)
2414                 goto free_cachep;
2415
2416         err = extent_map_init();
2417         if (err)
2418                 goto free_extent_io;
2419
2420         err = ordered_data_init();
2421         if (err)
2422                 goto free_extent_map;
2423
2424         err = btrfs_delayed_inode_init();
2425         if (err)
2426                 goto free_ordered_data;
2427
2428         err = btrfs_auto_defrag_init();
2429         if (err)
2430                 goto free_delayed_inode;
2431
2432         err = btrfs_delayed_ref_init();
2433         if (err)
2434                 goto free_auto_defrag;
2435
2436         err = btrfs_prelim_ref_init();
2437         if (err)
2438                 goto free_delayed_ref;
2439
2440         err = btrfs_end_io_wq_init();
2441         if (err)
2442                 goto free_prelim_ref;
2443
2444         err = btrfs_interface_init();
2445         if (err)
2446                 goto free_end_io_wq;
2447
2448         btrfs_init_lockdep();
2449
2450         btrfs_print_mod_info();
2451
2452         err = btrfs_run_sanity_tests();
2453         if (err)
2454                 goto unregister_ioctl;
2455
2456         err = register_filesystem(&btrfs_fs_type);
2457         if (err)
2458                 goto unregister_ioctl;
2459
2460         return 0;
2461
2462 unregister_ioctl:
2463         btrfs_interface_exit();
2464 free_end_io_wq:
2465         btrfs_end_io_wq_exit();
2466 free_prelim_ref:
2467         btrfs_prelim_ref_exit();
2468 free_delayed_ref:
2469         btrfs_delayed_ref_exit();
2470 free_auto_defrag:
2471         btrfs_auto_defrag_exit();
2472 free_delayed_inode:
2473         btrfs_delayed_inode_exit();
2474 free_ordered_data:
2475         ordered_data_exit();
2476 free_extent_map:
2477         extent_map_exit();
2478 free_extent_io:
2479         extent_io_exit();
2480 free_cachep:
2481         btrfs_destroy_cachep();
2482 free_compress:
2483         btrfs_exit_compress();
2484         btrfs_exit_sysfs();
2485 free_hash:
2486         btrfs_hash_exit();
2487         return err;
2488 }
2489
2490 static void __exit exit_btrfs_fs(void)
2491 {
2492         btrfs_destroy_cachep();
2493         btrfs_delayed_ref_exit();
2494         btrfs_auto_defrag_exit();
2495         btrfs_delayed_inode_exit();
2496         btrfs_prelim_ref_exit();
2497         ordered_data_exit();
2498         extent_map_exit();
2499         extent_io_exit();
2500         btrfs_interface_exit();
2501         btrfs_end_io_wq_exit();
2502         unregister_filesystem(&btrfs_fs_type);
2503         btrfs_exit_sysfs();
2504         btrfs_cleanup_fs_uuids();
2505         btrfs_exit_compress();
2506         btrfs_hash_exit();
2507 }
2508
2509 late_initcall(init_btrfs_fs);
2510 module_exit(exit_btrfs_fs)
2511
2512 MODULE_LICENSE("GPL");