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 ommited. 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                 printk(KERN_CRIT
 155                         "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 156                         sb->s_id, function, line, errno, errstr, &vaf);
 157                 va_end(args);
 158         } else {
 159                 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 160                         sb->s_id, function, line, errno, errstr);
 161         }
 162 #endif
 163
 164         /*
 165          * Today we only save the error info to memory.  Long term we'll
 166          * also send it down to the disk
 167          */
 168         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 169
 170         /* Don't go through full error handling during mount */
 171         if (sb->s_flags & MS_BORN)
 172                 btrfs_handle_error(fs_info);
 173 }
 174
 175 #ifdef CONFIG_PRINTK
 176 static const char * const logtypes[] = {
 177         "emergency",
 178         "alert",
 179         "critical",
 180         "error",
 181         "warning",
 182         "notice",
 183         "info",
 184         "debug",
 185 };
 186
 187 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 188 {
 189         struct super_block *sb = fs_info->sb;
 190         char lvl[4];
 191         struct va_format vaf;
 192         va_list args;
 193         const char *type = logtypes[4];
 194         int kern_level;
 195
 196         va_start(args, fmt);
 197
 198         kern_level = printk_get_level(fmt);
 199         if (kern_level) {
 200                 size_t size = printk_skip_level(fmt) - fmt;
 201                 memcpy(lvl, fmt,  size);
 202                 lvl[size] = '\0';
 203                 fmt += size;
 204                 type = logtypes[kern_level - '0'];
 205         } else
 206                 *lvl = '\0';
 207
 208         vaf.fmt = fmt;
 209         vaf.va = &args;
 210
 211         printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
 212
 213         va_end(args);
 214 }
 215 #endif
 216
 217 /*
 218  * We only mark the transaction aborted and then set the file system read-only.
 219  * This will prevent new transactions from starting or trying to join this
 220  * one.
 221  *
 222  * This means that error recovery at the call site is limited to freeing
 223  * any local memory allocations and passing the error code up without
 224  * further cleanup. The transaction should complete as it normally would
 225  * in the call path but will return -EIO.
 226  *
 227  * We'll complete the cleanup in btrfs_end_transaction and
 228  * btrfs_commit_transaction.
 229  */
 230 __cold
 231 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 232                                struct btrfs_root *root, const char *function,
 233                                unsigned int line, int errno)
 234 {
 235         trans->aborted = errno;
 236         /* Nothing used. The other threads that have joined this
 237          * transaction may be able to continue. */
 238         if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
 239                 const char *errstr;
 240
 241                 errstr = btrfs_decode_error(errno);
 242                 btrfs_warn(root->fs_info,
 243                            "%s:%d: Aborting unused transaction(%s).",
 244                            function, line, errstr);
 245                 return;
 246         }
 247         ACCESS_ONCE(trans->transaction->aborted) = errno;
 248         /* Wake up anybody who may be waiting on this transaction */
 249         wake_up(&root->fs_info->transaction_wait);
 250         wake_up(&root->fs_info->transaction_blocked_wait);
 251         __btrfs_handle_fs_error(root->fs_info, function, line, errno, NULL);
 252 }
 253 /*
 254  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 255  * issues an alert, and either panics or BUGs, depending on mount options.
 256  */
 257 __cold
 258 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 259                    unsigned int line, int errno, const char *fmt, ...)
 260 {
 261         char *s_id = "<unknown>";
 262         const char *errstr;
 263         struct va_format vaf = { .fmt = fmt };
 264         va_list args;
 265
 266         if (fs_info)
 267                 s_id = fs_info->sb->s_id;
 268
 269         va_start(args, fmt);
 270         vaf.va = &args;
 271
 272         errstr = btrfs_decode_error(errno);
 273         if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
 274                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 275                         s_id, function, line, &vaf, errno, errstr);
 276
 277         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 278                    function, line, &vaf, errno, errstr);
 279         va_end(args);
 280         /* Caller calls BUG() */
 281 }
 282
 283 static void btrfs_put_super(struct super_block *sb)
 284 {
 285         close_ctree(btrfs_sb(sb)->tree_root);
 286 }
 287
 288 enum {
 289         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 290         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 291         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 292         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 293         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 294         Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 295         Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 296         Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 297         Opt_skip_balance, Opt_check_integrity,
 298         Opt_check_integrity_including_extent_data,
 299         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 300         Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
 301         Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
 302         Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
 303         Opt_nologreplay, Opt_norecovery,
 304 #ifdef CONFIG_BTRFS_DEBUG
 305         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 306 #endif
 307         Opt_err,
 308 };
 309
 310 static const match_table_t tokens = {
 311         {Opt_degraded, "degraded"},
 312         {Opt_subvol, "subvol=%s"},
 313         {Opt_subvolid, "subvolid=%s"},
 314         {Opt_device, "device=%s"},
 315         {Opt_nodatasum, "nodatasum"},
 316         {Opt_datasum, "datasum"},
 317         {Opt_nodatacow, "nodatacow"},
 318         {Opt_datacow, "datacow"},
 319         {Opt_nobarrier, "nobarrier"},
 320         {Opt_barrier, "barrier"},
 321         {Opt_max_inline, "max_inline=%s"},
 322         {Opt_alloc_start, "alloc_start=%s"},
 323         {Opt_thread_pool, "thread_pool=%d"},
 324         {Opt_compress, "compress"},
 325         {Opt_compress_type, "compress=%s"},
 326         {Opt_compress_force, "compress-force"},
 327         {Opt_compress_force_type, "compress-force=%s"},
 328         {Opt_ssd, "ssd"},
 329         {Opt_ssd_spread, "ssd_spread"},
 330         {Opt_nossd, "nossd"},
 331         {Opt_acl, "acl"},
 332         {Opt_noacl, "noacl"},
 333         {Opt_notreelog, "notreelog"},
 334         {Opt_treelog, "treelog"},
 335         {Opt_nologreplay, "nologreplay"},
 336         {Opt_norecovery, "norecovery"},
 337         {Opt_flushoncommit, "flushoncommit"},
 338         {Opt_noflushoncommit, "noflushoncommit"},
 339         {Opt_ratio, "metadata_ratio=%d"},
 340         {Opt_discard, "discard"},
 341         {Opt_nodiscard, "nodiscard"},
 342         {Opt_space_cache, "space_cache"},
 343         {Opt_space_cache_version, "space_cache=%s"},
 344         {Opt_clear_cache, "clear_cache"},
 345         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 346         {Opt_enospc_debug, "enospc_debug"},
 347         {Opt_noenospc_debug, "noenospc_debug"},
 348         {Opt_subvolrootid, "subvolrootid=%d"},
 349         {Opt_defrag, "autodefrag"},
 350         {Opt_nodefrag, "noautodefrag"},
 351         {Opt_inode_cache, "inode_cache"},
 352         {Opt_noinode_cache, "noinode_cache"},
 353         {Opt_no_space_cache, "nospace_cache"},
 354         {Opt_recovery, "recovery"}, /* deprecated */
 355         {Opt_usebackuproot, "usebackuproot"},
 356         {Opt_skip_balance, "skip_balance"},
 357         {Opt_check_integrity, "check_int"},
 358         {Opt_check_integrity_including_extent_data, "check_int_data"},
 359         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 360         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 361         {Opt_fatal_errors, "fatal_errors=%s"},
 362         {Opt_commit_interval, "commit=%d"},
 363 #ifdef CONFIG_BTRFS_DEBUG
 364         {Opt_fragment_data, "fragment=data"},
 365         {Opt_fragment_metadata, "fragment=metadata"},
 366         {Opt_fragment_all, "fragment=all"},
 367 #endif
 368         {Opt_err, NULL},
 369 };
 370
 371 /*
 372  * Regular mount options parser.  Everything that is needed only when
 373  * reading in a new superblock is parsed here.
 374  * XXX JDM: This needs to be cleaned up for remount.
 375  */
 376 int btrfs_parse_options(struct btrfs_root *root, char *options,
 377                         unsigned long new_flags)
 378 {
 379         struct btrfs_fs_info *info = root->fs_info;
 380         substring_t args[MAX_OPT_ARGS];
 381         char *p, *num, *orig = NULL;
 382         u64 cache_gen;
 383         int intarg;
 384         int ret = 0;
 385         char *compress_type;
 386         bool compress_force = false;
 387         enum btrfs_compression_type saved_compress_type;
 388         bool saved_compress_force;
 389         int no_compress = 0;
 390
 391         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 392         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
 393                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 394         else if (cache_gen)
 395                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 396
 397         /*
 398          * Even the options are empty, we still need to do extra check
 399          * against new flags
 400          */
 401         if (!options)
 402                 goto check;
 403
 404         /*
 405          * strsep changes the string, duplicate it because parse_options
 406          * gets called twice
 407          */
 408         options = kstrdup(options, GFP_NOFS);
 409         if (!options)
 410                 return -ENOMEM;
 411
 412         orig = options;
 413
 414         while ((p = strsep(&options, ",")) != NULL) {
 415                 int token;
 416                 if (!*p)
 417                         continue;
 418
 419                 token = match_token(p, tokens, args);
 420                 switch (token) {
 421                 case Opt_degraded:
 422                         btrfs_info(root->fs_info, "allowing degraded mounts");
 423                         btrfs_set_opt(info->mount_opt, DEGRADED);
 424                         break;
 425                 case Opt_subvol:
 426                 case Opt_subvolid:
 427                 case Opt_subvolrootid:
 428                 case Opt_device:
 429                         /*
 430                          * These are parsed by btrfs_parse_early_options
 431                          * and can be happily ignored here.
 432                          */
 433                         break;
 434                 case Opt_nodatasum:
 435                         btrfs_set_and_info(root, NODATASUM,
 436                                            "setting nodatasum");
 437                         break;
 438                 case Opt_datasum:
 439                         if (btrfs_test_opt(root, NODATASUM)) {
 440                                 if (btrfs_test_opt(root, NODATACOW))
 441                                         btrfs_info(root->fs_info, "setting datasum, datacow enabled");
 442                                 else
 443                                         btrfs_info(root->fs_info, "setting datasum");
 444                         }
 445                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 446                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 447                         break;
 448                 case Opt_nodatacow:
 449                         if (!btrfs_test_opt(root, NODATACOW)) {
 450                                 if (!btrfs_test_opt(root, COMPRESS) ||
 451                                     !btrfs_test_opt(root, FORCE_COMPRESS)) {
 452                                         btrfs_info(root->fs_info,
 453                                                    "setting nodatacow, compression disabled");
 454                                 } else {
 455                                         btrfs_info(root->fs_info, "setting nodatacow");
 456                                 }
 457                         }
 458                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 459                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 460                         btrfs_set_opt(info->mount_opt, NODATACOW);
 461                         btrfs_set_opt(info->mount_opt, NODATASUM);
 462                         break;
 463                 case Opt_datacow:
 464                         btrfs_clear_and_info(root, NODATACOW,
 465                                              "setting datacow");
 466                         break;
 467                 case Opt_compress_force:
 468                 case Opt_compress_force_type:
 469                         compress_force = true;
 470                         /* Fallthrough */
 471                 case Opt_compress:
 472                 case Opt_compress_type:
 473                         saved_compress_type = btrfs_test_opt(root, COMPRESS) ?
 474                                 info->compress_type : BTRFS_COMPRESS_NONE;
 475                         saved_compress_force =
 476                                 btrfs_test_opt(root, FORCE_COMPRESS);
 477                         if (token == Opt_compress ||
 478                             token == Opt_compress_force ||
 479                             strcmp(args[0].from, "zlib") == 0) {
 480                                 compress_type = "zlib";
 481                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 482                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 483                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 484                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 485                                 no_compress = 0;
 486                         } else if (strcmp(args[0].from, "lzo") == 0) {
 487                                 compress_type = "lzo";
 488                                 info->compress_type = BTRFS_COMPRESS_LZO;
 489                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 490                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 491                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 492                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 493                                 no_compress = 0;
 494                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 495                                 compress_type = "no";
 496                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 497                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 498                                 compress_force = false;
 499                                 no_compress++;
 500                         } else {
 501                                 ret = -EINVAL;
 502                                 goto out;
 503                         }
 504
 505                         if (compress_force) {
 506                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 507                         } else {
 508                                 /*
 509                                  * If we remount from compress-force=xxx to
 510                                  * compress=xxx, we need clear FORCE_COMPRESS
 511                                  * flag, otherwise, there is no way for users
 512                                  * to disable forcible compression separately.
 513                                  */
 514                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 515                         }
 516                         if ((btrfs_test_opt(root, COMPRESS) &&
 517                              (info->compress_type != saved_compress_type ||
 518                               compress_force != saved_compress_force)) ||
 519                             (!btrfs_test_opt(root, COMPRESS) &&
 520                              no_compress == 1)) {
 521                                 btrfs_info(root->fs_info,
 522                                            "%s %s compression",
 523                                            (compress_force) ? "force" : "use",
 524                                            compress_type);
 525                         }
 526                         compress_force = false;
 527                         break;
 528                 case Opt_ssd:
 529                         btrfs_set_and_info(root, SSD,
 530                                            "use ssd allocation scheme");
 531                         break;
 532                 case Opt_ssd_spread:
 533                         btrfs_set_and_info(root, SSD_SPREAD,
 534                                            "use spread ssd allocation scheme");
 535                         btrfs_set_opt(info->mount_opt, SSD);
 536                         break;
 537                 case Opt_nossd:
 538                         btrfs_set_and_info(root, NOSSD,
 539                                              "not using ssd allocation scheme");
 540                         btrfs_clear_opt(info->mount_opt, SSD);
 541                         break;
 542                 case Opt_barrier:
 543                         btrfs_clear_and_info(root, NOBARRIER,
 544                                              "turning on barriers");
 545                         break;
 546                 case Opt_nobarrier:
 547                         btrfs_set_and_info(root, NOBARRIER,
 548                                            "turning off barriers");
 549                         break;
 550                 case Opt_thread_pool:
 551                         ret = match_int(&args[0], &intarg);
 552                         if (ret) {
 553                                 goto out;
 554                         } else if (intarg > 0) {
 555                                 info->thread_pool_size = intarg;
 556                         } else {
 557                                 ret = -EINVAL;
 558                                 goto out;
 559                         }
 560                         break;
 561                 case Opt_max_inline:
 562                         num = match_strdup(&args[0]);
 563                         if (num) {
 564                                 info->max_inline = memparse(num, NULL);
 565                                 kfree(num);
 566
 567                                 if (info->max_inline) {
 568                                         info->max_inline = min_t(u64,
 569                                                 info->max_inline,
 570                                                 root->sectorsize);
 571                                 }
 572                                 btrfs_info(root->fs_info, "max_inline at %llu",
 573                                         info->max_inline);
 574                         } else {
 575                                 ret = -ENOMEM;
 576                                 goto out;
 577                         }
 578                         break;
 579                 case Opt_alloc_start:
 580                         num = match_strdup(&args[0]);
 581                         if (num) {
 582                                 mutex_lock(&info->chunk_mutex);
 583                                 info->alloc_start = memparse(num, NULL);
 584                                 mutex_unlock(&info->chunk_mutex);
 585                                 kfree(num);
 586                                 btrfs_info(root->fs_info, "allocations start at %llu",
 587                                         info->alloc_start);
 588                         } else {
 589                                 ret = -ENOMEM;
 590                                 goto out;
 591                         }
 592                         break;
 593                 case Opt_acl:
 594 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 595                         root->fs_info->sb->s_flags |= MS_POSIXACL;
 596                         break;
 597 #else
 598                         btrfs_err(root->fs_info,
 599                                 "support for ACL not compiled in!");
 600                         ret = -EINVAL;
 601                         goto out;
 602 #endif
 603                 case Opt_noacl:
 604                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 605                         break;
 606                 case Opt_notreelog:
 607                         btrfs_set_and_info(root, NOTREELOG,
 608                                            "disabling tree log");
 609                         break;
 610                 case Opt_treelog:
 611                         btrfs_clear_and_info(root, NOTREELOG,
 612                                              "enabling tree log");
 613                         break;
 614                 case Opt_norecovery:
 615                 case Opt_nologreplay:
 616                         btrfs_set_and_info(root, NOLOGREPLAY,
 617                                            "disabling log replay at mount time");
 618                         break;
 619                 case Opt_flushoncommit:
 620                         btrfs_set_and_info(root, FLUSHONCOMMIT,
 621                                            "turning on flush-on-commit");
 622                         break;
 623                 case Opt_noflushoncommit:
 624                         btrfs_clear_and_info(root, FLUSHONCOMMIT,
 625                                              "turning off flush-on-commit");
 626                         break;
 627                 case Opt_ratio:
 628                         ret = match_int(&args[0], &intarg);
 629                         if (ret) {
 630                                 goto out;
 631                         } else if (intarg >= 0) {
 632                                 info->metadata_ratio = intarg;
 633                                 btrfs_info(root->fs_info, "metadata ratio %d",
 634                                        info->metadata_ratio);
 635                         } else {
 636                                 ret = -EINVAL;
 637                                 goto out;
 638                         }
 639                         break;
 640                 case Opt_discard:
 641                         btrfs_set_and_info(root, DISCARD,
 642                                            "turning on discard");
 643                         break;
 644                 case Opt_nodiscard:
 645                         btrfs_clear_and_info(root, DISCARD,
 646                                              "turning off discard");
 647                         break;
 648                 case Opt_space_cache:
 649                 case Opt_space_cache_version:
 650                         if (token == Opt_space_cache ||
 651                             strcmp(args[0].from, "v1") == 0) {
 652                                 btrfs_clear_opt(root->fs_info->mount_opt,
 653                                                 FREE_SPACE_TREE);
 654                                 btrfs_set_and_info(root, SPACE_CACHE,
 655                                                    "enabling disk space caching");
 656                         } else if (strcmp(args[0].from, "v2") == 0) {
 657                                 btrfs_clear_opt(root->fs_info->mount_opt,
 658                                                 SPACE_CACHE);
 659                                 btrfs_set_and_info(root, FREE_SPACE_TREE,
 660                                                    "enabling free space tree");
 661                         } else {
 662                                 ret = -EINVAL;
 663                                 goto out;
 664                         }
 665                         break;
 666                 case Opt_rescan_uuid_tree:
 667                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 668                         break;
 669                 case Opt_no_space_cache:
 670                         if (btrfs_test_opt(root, SPACE_CACHE)) {
 671                                 btrfs_clear_and_info(root, SPACE_CACHE,
 672                                                      "disabling disk space caching");
 673                         }
 674                         if (btrfs_test_opt(root, FREE_SPACE_TREE)) {
 675                                 btrfs_clear_and_info(root, FREE_SPACE_TREE,
 676                                                      "disabling free space tree");
 677                         }
 678                         break;
 679                 case Opt_inode_cache:
 680                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 681                                            "enabling inode map caching");
 682                         break;
 683                 case Opt_noinode_cache:
 684                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 685                                              "disabling inode map caching");
 686                         break;
 687                 case Opt_clear_cache:
 688                         btrfs_set_and_info(root, CLEAR_CACHE,
 689                                            "force clearing of disk cache");
 690                         break;
 691                 case Opt_user_subvol_rm_allowed:
 692                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 693                         break;
 694                 case Opt_enospc_debug:
 695                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 696                         break;
 697                 case Opt_noenospc_debug:
 698                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 699                         break;
 700                 case Opt_defrag:
 701                         btrfs_set_and_info(root, AUTO_DEFRAG,
 702                                            "enabling auto defrag");
 703                         break;
 704                 case Opt_nodefrag:
 705                         btrfs_clear_and_info(root, AUTO_DEFRAG,
 706                                              "disabling auto defrag");
 707                         break;
 708                 case Opt_recovery:
 709                         btrfs_warn(root->fs_info,
 710                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 711                 case Opt_usebackuproot:
 712                         btrfs_info(root->fs_info,
 713                                    "trying to use backup root at mount time");
 714                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 715                         break;
 716                 case Opt_skip_balance:
 717                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 718                         break;
 719 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 720                 case Opt_check_integrity_including_extent_data:
 721                         btrfs_info(root->fs_info,
 722                                    "enabling check integrity including extent data");
 723                         btrfs_set_opt(info->mount_opt,
 724                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 725                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 726                         break;
 727                 case Opt_check_integrity:
 728                         btrfs_info(root->fs_info, "enabling check integrity");
 729                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 730                         break;
 731                 case Opt_check_integrity_print_mask:
 732                         ret = match_int(&args[0], &intarg);
 733                         if (ret) {
 734                                 goto out;
 735                         } else if (intarg >= 0) {
 736                                 info->check_integrity_print_mask = intarg;
 737                                 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
 738                                        info->check_integrity_print_mask);
 739                         } else {
 740                                 ret = -EINVAL;
 741                                 goto out;
 742                         }
 743                         break;
 744 #else
 745                 case Opt_check_integrity_including_extent_data:
 746                 case Opt_check_integrity:
 747                 case Opt_check_integrity_print_mask:
 748                         btrfs_err(root->fs_info,
 749                                 "support for check_integrity* not compiled in!");
 750                         ret = -EINVAL;
 751                         goto out;
 752 #endif
 753                 case Opt_fatal_errors:
 754                         if (strcmp(args[0].from, "panic") == 0)
 755                                 btrfs_set_opt(info->mount_opt,
 756                                               PANIC_ON_FATAL_ERROR);
 757                         else if (strcmp(args[0].from, "bug") == 0)
 758                                 btrfs_clear_opt(info->mount_opt,
 759                                               PANIC_ON_FATAL_ERROR);
 760                         else {
 761                                 ret = -EINVAL;
 762                                 goto out;
 763                         }
 764                         break;
 765                 case Opt_commit_interval:
 766                         intarg = 0;
 767                         ret = match_int(&args[0], &intarg);
 768                         if (ret < 0) {
 769                                 btrfs_err(root->fs_info, "invalid commit interval");
 770                                 ret = -EINVAL;
 771                                 goto out;
 772                         }
 773                         if (intarg > 0) {
 774                                 if (intarg > 300) {
 775                                         btrfs_warn(root->fs_info, "excessive commit interval %d",
 776                                                         intarg);
 777                                 }
 778                                 info->commit_interval = intarg;
 779                         } else {
 780                                 btrfs_info(root->fs_info, "using default commit interval %ds",
 781                                     BTRFS_DEFAULT_COMMIT_INTERVAL);
 782                                 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 783                         }
 784                         break;
 785 #ifdef CONFIG_BTRFS_DEBUG
 786                 case Opt_fragment_all:
 787                         btrfs_info(root->fs_info, "fragmenting all space");
 788                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 789                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 790                         break;
 791                 case Opt_fragment_metadata:
 792                         btrfs_info(root->fs_info, "fragmenting metadata");
 793                         btrfs_set_opt(info->mount_opt,
 794                                       FRAGMENT_METADATA);
 795                         break;
 796                 case Opt_fragment_data:
 797                         btrfs_info(root->fs_info, "fragmenting data");
 798                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 799                         break;
 800 #endif
 801                 case Opt_err:
 802                         btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
 803                         ret = -EINVAL;
 804                         goto out;
 805                 default:
 806                         break;
 807                 }
 808         }
 809 check:
 810         /*
 811          * Extra check for current option against current flag
 812          */
 813         if (btrfs_test_opt(root, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
 814                 btrfs_err(root->fs_info,
 815                           "nologreplay must be used with ro mount option");
 816                 ret = -EINVAL;
 817         }
 818 out:
 819         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
 820             !btrfs_test_opt(root, FREE_SPACE_TREE) &&
 821             !btrfs_test_opt(root, CLEAR_CACHE)) {
 822                 btrfs_err(root->fs_info, "cannot disable free space tree");
 823                 ret = -EINVAL;
 824
 825         }
 826         if (!ret && btrfs_test_opt(root, SPACE_CACHE))
 827                 btrfs_info(root->fs_info, "disk space caching is enabled");
 828         if (!ret && btrfs_test_opt(root, FREE_SPACE_TREE))
 829                 btrfs_info(root->fs_info, "using free space tree");
 830         kfree(orig);
 831         return ret;
 832 }
 833
 834 /*
 835  * Parse mount options that are required early in the mount process.
 836  *
 837  * All other options will be parsed on much later in the mount process and
 838  * only when we need to allocate a new super block.
 839  */
 840 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 841                 void *holder, char **subvol_name, u64 *subvol_objectid,
 842                 struct btrfs_fs_devices **fs_devices)
 843 {
 844         substring_t args[MAX_OPT_ARGS];
 845         char *device_name, *opts, *orig, *p;
 846         char *num = NULL;
 847         int error = 0;
 848
 849         if (!options)
 850                 return 0;
 851
 852         /*
 853          * strsep changes the string, duplicate it because parse_options
 854          * gets called twice
 855          */
 856         opts = kstrdup(options, GFP_KERNEL);
 857         if (!opts)
 858                 return -ENOMEM;
 859         orig = opts;
 860
 861         while ((p = strsep(&opts, ",")) != NULL) {
 862                 int token;
 863                 if (!*p)
 864                         continue;
 865
 866                 token = match_token(p, tokens, args);
 867                 switch (token) {
 868                 case Opt_subvol:
 869                         kfree(*subvol_name);
 870                         *subvol_name = match_strdup(&args[0]);
 871                         if (!*subvol_name) {
 872                                 error = -ENOMEM;
 873                                 goto out;
 874                         }
 875                         break;
 876                 case Opt_subvolid:
 877                         num = match_strdup(&args[0]);
 878                         if (num) {
 879                                 *subvol_objectid = memparse(num, NULL);
 880                                 kfree(num);
 881                                 /* we want the original fs_tree */
 882                                 if (!*subvol_objectid)
 883                                         *subvol_objectid =
 884                                                 BTRFS_FS_TREE_OBJECTID;
 885                         } else {
 886                                 error = -EINVAL;
 887                                 goto out;
 888                         }
 889                         break;
 890                 case Opt_subvolrootid:
 891                         printk(KERN_WARNING
 892                                 "BTRFS: 'subvolrootid' mount option is deprecated and has "
 893                                 "no effect\n");
 894                         break;
 895                 case Opt_device:
 896                         device_name = match_strdup(&args[0]);
 897                         if (!device_name) {
 898                                 error = -ENOMEM;
 899                                 goto out;
 900                         }
 901                         error = btrfs_scan_one_device(device_name,
 902                                         flags, holder, fs_devices);
 903                         kfree(device_name);
 904                         if (error)
 905                                 goto out;
 906                         break;
 907                 default:
 908                         break;
 909                 }
 910         }
 911
 912 out:
 913         kfree(orig);
 914         return error;
 915 }
 916
 917 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 918                                            u64 subvol_objectid)
 919 {
 920         struct btrfs_root *root = fs_info->tree_root;
 921         struct btrfs_root *fs_root;
 922         struct btrfs_root_ref *root_ref;
 923         struct btrfs_inode_ref *inode_ref;
 924         struct btrfs_key key;
 925         struct btrfs_path *path = NULL;
 926         char *name = NULL, *ptr;
 927         u64 dirid;
 928         int len;
 929         int ret;
 930
 931         path = btrfs_alloc_path();
 932         if (!path) {
 933                 ret = -ENOMEM;
 934                 goto err;
 935         }
 936         path->leave_spinning = 1;
 937
 938         name = kmalloc(PATH_MAX, GFP_NOFS);
 939         if (!name) {
 940                 ret = -ENOMEM;
 941                 goto err;
 942         }
 943         ptr = name + PATH_MAX - 1;
 944         ptr[0] = '\0';
 945
 946         /*
 947          * Walk up the subvolume trees in the tree of tree roots by root
 948          * backrefs until we hit the top-level subvolume.
 949          */
 950         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 951                 key.objectid = subvol_objectid;
 952                 key.type = BTRFS_ROOT_BACKREF_KEY;
 953                 key.offset = (u64)-1;
 954
 955                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 956                 if (ret < 0) {
 957                         goto err;
 958                 } else if (ret > 0) {
 959                         ret = btrfs_previous_item(root, path, subvol_objectid,
 960                                                   BTRFS_ROOT_BACKREF_KEY);
 961                         if (ret < 0) {
 962                                 goto err;
 963                         } else if (ret > 0) {
 964                                 ret = -ENOENT;
 965                                 goto err;
 966                         }
 967                 }
 968
 969                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 970                 subvol_objectid = key.offset;
 971
 972                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 973                                           struct btrfs_root_ref);
 974                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
 975                 ptr -= len + 1;
 976                 if (ptr < name) {
 977                         ret = -ENAMETOOLONG;
 978                         goto err;
 979                 }
 980                 read_extent_buffer(path->nodes[0], ptr + 1,
 981                                    (unsigned long)(root_ref + 1), len);
 982                 ptr[0] = '/';
 983                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
 984                 btrfs_release_path(path);
 985
 986                 key.objectid = subvol_objectid;
 987                 key.type = BTRFS_ROOT_ITEM_KEY;
 988                 key.offset = (u64)-1;
 989                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
 990                 if (IS_ERR(fs_root)) {
 991                         ret = PTR_ERR(fs_root);
 992                         goto err;
 993                 }
 994
 995                 /*
 996                  * Walk up the filesystem tree by inode refs until we hit the
 997                  * root directory.
 998                  */
 999                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1000                         key.objectid = dirid;
1001                         key.type = BTRFS_INODE_REF_KEY;
1002                         key.offset = (u64)-1;
1003
1004                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1005                         if (ret < 0) {
1006                                 goto err;
1007                         } else if (ret > 0) {
1008                                 ret = btrfs_previous_item(fs_root, path, dirid,
1009                                                           BTRFS_INODE_REF_KEY);
1010                                 if (ret < 0) {
1011                                         goto err;
1012                                 } else if (ret > 0) {
1013                                         ret = -ENOENT;
1014                                         goto err;
1015                                 }
1016                         }
1017
1018                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1019                         dirid = key.offset;
1020
1021                         inode_ref = btrfs_item_ptr(path->nodes[0],
1022                                                    path->slots[0],
1023                                                    struct btrfs_inode_ref);
1024                         len = btrfs_inode_ref_name_len(path->nodes[0],
1025                                                        inode_ref);
1026                         ptr -= len + 1;
1027                         if (ptr < name) {
1028                                 ret = -ENAMETOOLONG;
1029                                 goto err;
1030                         }
1031                         read_extent_buffer(path->nodes[0], ptr + 1,
1032                                            (unsigned long)(inode_ref + 1), len);
1033                         ptr[0] = '/';
1034                         btrfs_release_path(path);
1035                 }
1036         }
1037
1038         btrfs_free_path(path);
1039         if (ptr == name + PATH_MAX - 1) {
1040                 name[0] = '/';
1041                 name[1] = '\0';
1042         } else {
1043                 memmove(name, ptr, name + PATH_MAX - ptr);
1044         }
1045         return name;
1046
1047 err:
1048         btrfs_free_path(path);
1049         kfree(name);
1050         return ERR_PTR(ret);
1051 }
1052
1053 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1054 {
1055         struct btrfs_root *root = fs_info->tree_root;
1056         struct btrfs_dir_item *di;
1057         struct btrfs_path *path;
1058         struct btrfs_key location;
1059         u64 dir_id;
1060
1061         path = btrfs_alloc_path();
1062         if (!path)
1063                 return -ENOMEM;
1064         path->leave_spinning = 1;
1065
1066         /*
1067          * Find the "default" dir item which points to the root item that we
1068          * will mount by default if we haven't been given a specific subvolume
1069          * to mount.
1070          */
1071         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1072         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1073         if (IS_ERR(di)) {
1074                 btrfs_free_path(path);
1075                 return PTR_ERR(di);
1076         }
1077         if (!di) {
1078                 /*
1079                  * Ok the default dir item isn't there.  This is weird since
1080                  * it's always been there, but don't freak out, just try and
1081                  * mount the top-level subvolume.
1082                  */
1083                 btrfs_free_path(path);
1084                 *objectid = BTRFS_FS_TREE_OBJECTID;
1085                 return 0;
1086         }
1087
1088         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1089         btrfs_free_path(path);
1090         *objectid = location.objectid;
1091         return 0;
1092 }
1093
1094 static int btrfs_fill_super(struct super_block *sb,
1095                             struct btrfs_fs_devices *fs_devices,
1096                             void *data, int silent)
1097 {
1098         struct inode *inode;
1099         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1100         struct btrfs_key key;
1101         int err;
1102
1103         sb->s_maxbytes = MAX_LFS_FILESIZE;
1104         sb->s_magic = BTRFS_SUPER_MAGIC;
1105         sb->s_op = &btrfs_super_ops;
1106         sb->s_d_op = &btrfs_dentry_operations;
1107         sb->s_export_op = &btrfs_export_ops;
1108         sb->s_xattr = btrfs_xattr_handlers;
1109         sb->s_time_gran = 1;
1110 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1111         sb->s_flags |= MS_POSIXACL;
1112 #endif
1113         sb->s_flags |= MS_I_VERSION;
1114         sb->s_iflags |= SB_I_CGROUPWB;
1115         err = open_ctree(sb, fs_devices, (char *)data);
1116         if (err) {
1117                 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1118                 return err;
1119         }
1120
1121         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1122         key.type = BTRFS_INODE_ITEM_KEY;
1123         key.offset = 0;
1124         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1125         if (IS_ERR(inode)) {
1126                 err = PTR_ERR(inode);
1127                 goto fail_close;
1128         }
1129
1130         sb->s_root = d_make_root(inode);
1131         if (!sb->s_root) {
1132                 err = -ENOMEM;
1133                 goto fail_close;
1134         }
1135
1136         save_mount_options(sb, data);
1137         cleancache_init_fs(sb);
1138         sb->s_flags |= MS_ACTIVE;
1139         return 0;
1140
1141 fail_close:
1142         close_ctree(fs_info->tree_root);
1143         return err;
1144 }
1145
1146 int btrfs_sync_fs(struct super_block *sb, int wait)
1147 {
1148         struct btrfs_trans_handle *trans;
1149         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1150         struct btrfs_root *root = fs_info->tree_root;
1151
1152         trace_btrfs_sync_fs(wait);
1153
1154         if (!wait) {
1155                 filemap_flush(fs_info->btree_inode->i_mapping);
1156                 return 0;
1157         }
1158
1159         btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
1160
1161         trans = btrfs_attach_transaction_barrier(root);
1162         if (IS_ERR(trans)) {
1163                 /* no transaction, don't bother */
1164                 if (PTR_ERR(trans) == -ENOENT) {
1165                         /*
1166                          * Exit unless we have some pending changes
1167                          * that need to go through commit
1168                          */
1169                         if (fs_info->pending_changes == 0)
1170                                 return 0;
1171                         /*
1172                          * A non-blocking test if the fs is frozen. We must not
1173                          * start a new transaction here otherwise a deadlock
1174                          * happens. The pending operations are delayed to the
1175                          * next commit after thawing.
1176                          */
1177                         if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1178                                 __sb_end_write(sb, SB_FREEZE_WRITE);
1179                         else
1180                                 return 0;
1181                         trans = btrfs_start_transaction(root, 0);
1182                 }
1183                 if (IS_ERR(trans))
1184                         return PTR_ERR(trans);
1185         }
1186         return btrfs_commit_transaction(trans, root);
1187 }
1188
1189 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1190 {
1191         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1192         struct btrfs_root *root = info->tree_root;
1193         char *compress_type;
1194
1195         if (btrfs_test_opt(root, DEGRADED))
1196                 seq_puts(seq, ",degraded");
1197         if (btrfs_test_opt(root, NODATASUM))
1198                 seq_puts(seq, ",nodatasum");
1199         if (btrfs_test_opt(root, NODATACOW))
1200                 seq_puts(seq, ",nodatacow");
1201         if (btrfs_test_opt(root, NOBARRIER))
1202                 seq_puts(seq, ",nobarrier");
1203         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1204                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1205         if (info->alloc_start != 0)
1206                 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1207         if (info->thread_pool_size !=  min_t(unsigned long,
1208                                              num_online_cpus() + 2, 8))
1209                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1210         if (btrfs_test_opt(root, COMPRESS)) {
1211                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1212                         compress_type = "zlib";
1213                 else
1214                         compress_type = "lzo";
1215                 if (btrfs_test_opt(root, FORCE_COMPRESS))
1216                         seq_printf(seq, ",compress-force=%s", compress_type);
1217                 else
1218                         seq_printf(seq, ",compress=%s", compress_type);
1219         }
1220         if (btrfs_test_opt(root, NOSSD))
1221                 seq_puts(seq, ",nossd");
1222         if (btrfs_test_opt(root, SSD_SPREAD))
1223                 seq_puts(seq, ",ssd_spread");
1224         else if (btrfs_test_opt(root, SSD))
1225                 seq_puts(seq, ",ssd");
1226         if (btrfs_test_opt(root, NOTREELOG))
1227                 seq_puts(seq, ",notreelog");
1228         if (btrfs_test_opt(root, NOLOGREPLAY))
1229                 seq_puts(seq, ",nologreplay");
1230         if (btrfs_test_opt(root, FLUSHONCOMMIT))
1231                 seq_puts(seq, ",flushoncommit");
1232         if (btrfs_test_opt(root, DISCARD))
1233                 seq_puts(seq, ",discard");
1234         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1235                 seq_puts(seq, ",noacl");
1236         if (btrfs_test_opt(root, SPACE_CACHE))
1237                 seq_puts(seq, ",space_cache");
1238         else if (btrfs_test_opt(root, FREE_SPACE_TREE))
1239                 seq_puts(seq, ",space_cache=v2");
1240         else
1241                 seq_puts(seq, ",nospace_cache");
1242         if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1243                 seq_puts(seq, ",rescan_uuid_tree");
1244         if (btrfs_test_opt(root, CLEAR_CACHE))
1245                 seq_puts(seq, ",clear_cache");
1246         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1247                 seq_puts(seq, ",user_subvol_rm_allowed");
1248         if (btrfs_test_opt(root, ENOSPC_DEBUG))
1249                 seq_puts(seq, ",enospc_debug");
1250         if (btrfs_test_opt(root, AUTO_DEFRAG))
1251                 seq_puts(seq, ",autodefrag");
1252         if (btrfs_test_opt(root, INODE_MAP_CACHE))
1253                 seq_puts(seq, ",inode_cache");
1254         if (btrfs_test_opt(root, SKIP_BALANCE))
1255                 seq_puts(seq, ",skip_balance");
1256 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1257         if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1258                 seq_puts(seq, ",check_int_data");
1259         else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1260                 seq_puts(seq, ",check_int");
1261         if (info->check_integrity_print_mask)
1262                 seq_printf(seq, ",check_int_print_mask=%d",
1263                                 info->check_integrity_print_mask);
1264 #endif
1265         if (info->metadata_ratio)
1266                 seq_printf(seq, ",metadata_ratio=%d",
1267                                 info->metadata_ratio);
1268         if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1269                 seq_puts(seq, ",fatal_errors=panic");
1270         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1271                 seq_printf(seq, ",commit=%d", info->commit_interval);
1272 #ifdef CONFIG_BTRFS_DEBUG
1273         if (btrfs_test_opt(root, FRAGMENT_DATA))
1274                 seq_puts(seq, ",fragment=data");
1275         if (btrfs_test_opt(root, FRAGMENT_METADATA))
1276                 seq_puts(seq, ",fragment=metadata");
1277 #endif
1278         seq_printf(seq, ",subvolid=%llu",
1279                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1280         seq_puts(seq, ",subvol=");
1281         seq_dentry(seq, dentry, " \t\n\\");
1282         return 0;
1283 }
1284
1285 static int btrfs_test_super(struct super_block *s, void *data)
1286 {
1287         struct btrfs_fs_info *p = data;
1288         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1289
1290         return fs_info->fs_devices == p->fs_devices;
1291 }
1292
1293 static int btrfs_set_super(struct super_block *s, void *data)
1294 {
1295         int err = set_anon_super(s, data);
1296         if (!err)
1297                 s->s_fs_info = data;
1298         return err;
1299 }
1300
1301 /*
1302  * subvolumes are identified by ino 256
1303  */
1304 static inline int is_subvolume_inode(struct inode *inode)
1305 {
1306         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1307                 return 1;
1308         return 0;
1309 }
1310
1311 /*
1312  * This will add subvolid=0 to the argument string while removing any subvol=
1313  * and subvolid= arguments to make sure we get the top-level root for path
1314  * walking to the subvol we want.
1315  */
1316 static char *setup_root_args(char *args)
1317 {
1318         char *buf, *dst, *sep;
1319
1320         if (!args)
1321                 return kstrdup("subvolid=0", GFP_NOFS);
1322
1323         /* The worst case is that we add ",subvolid=0" to the end. */
1324         buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1325         if (!buf)
1326                 return NULL;
1327
1328         while (1) {
1329                 sep = strchrnul(args, ',');
1330                 if (!strstarts(args, "subvol=") &&
1331                     !strstarts(args, "subvolid=")) {
1332                         memcpy(dst, args, sep - args);
1333                         dst += sep - args;
1334                         *dst++ = ',';
1335                 }
1336                 if (*sep)
1337                         args = sep + 1;
1338                 else
1339                         break;
1340         }
1341         strcpy(dst, "subvolid=0");
1342
1343         return buf;
1344 }
1345
1346 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1347                                    int flags, const char *device_name,
1348                                    char *data)
1349 {
1350         struct dentry *root;
1351         struct vfsmount *mnt = NULL;
1352         char *newargs;
1353         int ret;
1354
1355         newargs = setup_root_args(data);
1356         if (!newargs) {
1357                 root = ERR_PTR(-ENOMEM);
1358                 goto out;
1359         }
1360
1361         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1362         if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1363                 if (flags & MS_RDONLY) {
1364                         mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1365                                              device_name, newargs);
1366                 } else {
1367                         mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1368                                              device_name, newargs);
1369                         if (IS_ERR(mnt)) {
1370                                 root = ERR_CAST(mnt);
1371                                 mnt = NULL;
1372                                 goto out;
1373                         }
1374
1375                         down_write(&mnt->mnt_sb->s_umount);
1376                         ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1377                         up_write(&mnt->mnt_sb->s_umount);
1378                         if (ret < 0) {
1379                                 root = ERR_PTR(ret);
1380                                 goto out;
1381                         }
1382                 }
1383         }
1384         if (IS_ERR(mnt)) {
1385                 root = ERR_CAST(mnt);
1386                 mnt = NULL;
1387                 goto out;
1388         }
1389
1390         if (!subvol_name) {
1391                 if (!subvol_objectid) {
1392                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1393                                                           &subvol_objectid);
1394                         if (ret) {
1395                                 root = ERR_PTR(ret);
1396                                 goto out;
1397                         }
1398                 }
1399                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1400                                                             subvol_objectid);
1401                 if (IS_ERR(subvol_name)) {
1402                         root = ERR_CAST(subvol_name);
1403                         subvol_name = NULL;
1404                         goto out;
1405                 }
1406
1407         }
1408
1409         root = mount_subtree(mnt, subvol_name);
1410         /* mount_subtree() drops our reference on the vfsmount. */
1411         mnt = NULL;
1412
1413         if (!IS_ERR(root)) {
1414                 struct super_block *s = root->d_sb;
1415                 struct inode *root_inode = d_inode(root);
1416                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1417
1418                 ret = 0;
1419                 if (!is_subvolume_inode(root_inode)) {
1420                         pr_err("BTRFS: '%s' is not a valid subvolume\n",
1421                                subvol_name);
1422                         ret = -EINVAL;
1423                 }
1424                 if (subvol_objectid && root_objectid != subvol_objectid) {
1425                         /*
1426                          * This will also catch a race condition where a
1427                          * subvolume which was passed by ID is renamed and
1428                          * another subvolume is renamed over the old location.
1429                          */
1430                         pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1431                                subvol_name, subvol_objectid);
1432                         ret = -EINVAL;
1433                 }
1434                 if (ret) {
1435                         dput(root);
1436                         root = ERR_PTR(ret);
1437                         deactivate_locked_super(s);
1438                 }
1439         }
1440
1441 out:
1442         mntput(mnt);
1443         kfree(newargs);
1444         kfree(subvol_name);
1445         return root;
1446 }
1447
1448 static int parse_security_options(char *orig_opts,
1449                                   struct security_mnt_opts *sec_opts)
1450 {
1451         char *secdata = NULL;
1452         int ret = 0;
1453
1454         secdata = alloc_secdata();
1455         if (!secdata)
1456                 return -ENOMEM;
1457         ret = security_sb_copy_data(orig_opts, secdata);
1458         if (ret) {
1459                 free_secdata(secdata);
1460                 return ret;
1461         }
1462         ret = security_sb_parse_opts_str(secdata, sec_opts);
1463         free_secdata(secdata);
1464         return ret;
1465 }
1466
1467 static int setup_security_options(struct btrfs_fs_info *fs_info,
1468                                   struct super_block *sb,
1469                                   struct security_mnt_opts *sec_opts)
1470 {
1471         int ret = 0;
1472
1473         /*
1474          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1475          * is valid.
1476          */
1477         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1478         if (ret)
1479                 return ret;
1480
1481 #ifdef CONFIG_SECURITY
1482         if (!fs_info->security_opts.num_mnt_opts) {
1483                 /* first time security setup, copy sec_opts to fs_info */
1484                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1485         } else {
1486                 /*
1487                  * Since SELinux (the only one supporting security_mnt_opts)
1488                  * does NOT support changing context during remount/mount of
1489                  * the same sb, this must be the same or part of the same
1490                  * security options, just free it.
1491                  */
1492                 security_free_mnt_opts(sec_opts);
1493         }
1494 #endif
1495         return ret;
1496 }
1497
1498 /*
1499  * Find a superblock for the given device / mount point.
1500  *
1501  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1502  *        for multiple device setup.  Make sure to keep it in sync.
1503  */
1504 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1505                 const char *device_name, void *data)
1506 {
1507         struct block_device *bdev = NULL;
1508         struct super_block *s;
1509         struct btrfs_fs_devices *fs_devices = NULL;
1510         struct btrfs_fs_info *fs_info = NULL;
1511         struct security_mnt_opts new_sec_opts;
1512         fmode_t mode = FMODE_READ;
1513         char *subvol_name = NULL;
1514         u64 subvol_objectid = 0;
1515         int error = 0;
1516
1517         if (!(flags & MS_RDONLY))
1518                 mode |= FMODE_WRITE;
1519
1520         error = btrfs_parse_early_options(data, mode, fs_type,
1521                                           &subvol_name, &subvol_objectid,
1522                                           &fs_devices);
1523         if (error) {
1524                 kfree(subvol_name);
1525                 return ERR_PTR(error);
1526         }
1527
1528         if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1529                 /* mount_subvol() will free subvol_name. */
1530                 return mount_subvol(subvol_name, subvol_objectid, flags,
1531                                     device_name, data);
1532         }
1533
1534         security_init_mnt_opts(&new_sec_opts);
1535         if (data) {
1536                 error = parse_security_options(data, &new_sec_opts);
1537                 if (error)
1538                         return ERR_PTR(error);
1539         }
1540
1541         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1542         if (error)
1543                 goto error_sec_opts;
1544
1545         /*
1546          * Setup a dummy root and fs_info for test/set super.  This is because
1547          * we don't actually fill this stuff out until open_ctree, but we need
1548          * it for searching for existing supers, so this lets us do that and
1549          * then open_ctree will properly initialize everything later.
1550          */
1551         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1552         if (!fs_info) {
1553                 error = -ENOMEM;
1554                 goto error_sec_opts;
1555         }
1556
1557         fs_info->fs_devices = fs_devices;
1558
1559         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1560         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1561         security_init_mnt_opts(&fs_info->security_opts);
1562         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1563                 error = -ENOMEM;
1564                 goto error_fs_info;
1565         }
1566
1567         error = btrfs_open_devices(fs_devices, mode, fs_type);
1568         if (error)
1569                 goto error_fs_info;
1570
1571         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1572                 error = -EACCES;
1573                 goto error_close_devices;
1574         }
1575
1576         bdev = fs_devices->latest_bdev;
1577         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1578                  fs_info);
1579         if (IS_ERR(s)) {
1580                 error = PTR_ERR(s);
1581                 goto error_close_devices;
1582         }
1583
1584         if (s->s_root) {
1585                 btrfs_close_devices(fs_devices);
1586                 free_fs_info(fs_info);
1587                 if ((flags ^ s->s_flags) & MS_RDONLY)
1588                         error = -EBUSY;
1589         } else {
1590                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1591                 btrfs_sb(s)->bdev_holder = fs_type;
1592                 error = btrfs_fill_super(s, fs_devices, data,
1593                                          flags & MS_SILENT ? 1 : 0);
1594         }
1595         if (error) {
1596                 deactivate_locked_super(s);
1597                 goto error_sec_opts;
1598         }
1599
1600         fs_info = btrfs_sb(s);
1601         error = setup_security_options(fs_info, s, &new_sec_opts);
1602         if (error) {
1603                 deactivate_locked_super(s);
1604                 goto error_sec_opts;
1605         }
1606
1607         return dget(s->s_root);
1608
1609 error_close_devices:
1610         btrfs_close_devices(fs_devices);
1611 error_fs_info:
1612         free_fs_info(fs_info);
1613 error_sec_opts:
1614         security_free_mnt_opts(&new_sec_opts);
1615         return ERR_PTR(error);
1616 }
1617
1618 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1619                                      int new_pool_size, int old_pool_size)
1620 {
1621         if (new_pool_size == old_pool_size)
1622                 return;
1623
1624         fs_info->thread_pool_size = new_pool_size;
1625
1626         btrfs_info(fs_info, "resize thread pool %d -> %d",
1627                old_pool_size, new_pool_size);
1628
1629         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1630         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1631         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1632         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1633         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1634         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1635         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1636                                 new_pool_size);
1637         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1638         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1639         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1640         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1641         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1642                                 new_pool_size);
1643 }
1644
1645 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1646 {
1647         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1648 }
1649
1650 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1651                                        unsigned long old_opts, int flags)
1652 {
1653         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1654             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1655              (flags & MS_RDONLY))) {
1656                 /* wait for any defraggers to finish */
1657                 wait_event(fs_info->transaction_wait,
1658                            (atomic_read(&fs_info->defrag_running) == 0));
1659                 if (flags & MS_RDONLY)
1660                         sync_filesystem(fs_info->sb);
1661         }
1662 }
1663
1664 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1665                                          unsigned long old_opts)
1666 {
1667         /*
1668          * We need to cleanup all defragable inodes if the autodefragment is
1669          * close or the filesystem is read only.
1670          */
1671         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1672             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1673              (fs_info->sb->s_flags & MS_RDONLY))) {
1674                 btrfs_cleanup_defrag_inodes(fs_info);
1675         }
1676
1677         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1678 }
1679
1680 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1681 {
1682         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1683         struct btrfs_root *root = fs_info->tree_root;
1684         unsigned old_flags = sb->s_flags;
1685         unsigned long old_opts = fs_info->mount_opt;
1686         unsigned long old_compress_type = fs_info->compress_type;
1687         u64 old_max_inline = fs_info->max_inline;
1688         u64 old_alloc_start = fs_info->alloc_start;
1689         int old_thread_pool_size = fs_info->thread_pool_size;
1690         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1691         int ret;
1692
1693         sync_filesystem(sb);
1694         btrfs_remount_prepare(fs_info);
1695
1696         if (data) {
1697                 struct security_mnt_opts new_sec_opts;
1698
1699                 security_init_mnt_opts(&new_sec_opts);
1700                 ret = parse_security_options(data, &new_sec_opts);
1701                 if (ret)
1702                         goto restore;
1703                 ret = setup_security_options(fs_info, sb,
1704                                              &new_sec_opts);
1705                 if (ret) {
1706                         security_free_mnt_opts(&new_sec_opts);
1707                         goto restore;
1708                 }
1709         }
1710
1711         ret = btrfs_parse_options(root, data, *flags);
1712         if (ret) {
1713                 ret = -EINVAL;
1714                 goto restore;
1715         }
1716
1717         btrfs_remount_begin(fs_info, old_opts, *flags);
1718         btrfs_resize_thread_pool(fs_info,
1719                 fs_info->thread_pool_size, old_thread_pool_size);
1720
1721         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1722                 goto out;
1723
1724         if (*flags & MS_RDONLY) {
1725                 /*
1726                  * this also happens on 'umount -rf' or on shutdown, when
1727                  * the filesystem is busy.
1728                  */
1729                 cancel_work_sync(&fs_info->async_reclaim_work);
1730
1731                 /* wait for the uuid_scan task to finish */
1732                 down(&fs_info->uuid_tree_rescan_sem);
1733                 /* avoid complains from lockdep et al. */
1734                 up(&fs_info->uuid_tree_rescan_sem);
1735
1736                 sb->s_flags |= MS_RDONLY;
1737
1738                 /*
1739                  * Setting MS_RDONLY will put the cleaner thread to
1740                  * sleep at the next loop if it's already active.
1741                  * If it's already asleep, we'll leave unused block
1742                  * groups on disk until we're mounted read-write again
1743                  * unless we clean them up here.
1744                  */
1745                 btrfs_delete_unused_bgs(fs_info);
1746
1747                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1748                 btrfs_scrub_cancel(fs_info);
1749                 btrfs_pause_balance(fs_info);
1750
1751                 ret = btrfs_commit_super(root);
1752                 if (ret)
1753                         goto restore;
1754         } else {
1755                 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1756                         btrfs_err(fs_info,
1757                                 "Remounting read-write after error is not allowed");
1758                         ret = -EINVAL;
1759                         goto restore;
1760                 }
1761                 if (fs_info->fs_devices->rw_devices == 0) {
1762                         ret = -EACCES;
1763                         goto restore;
1764                 }
1765
1766                 if (fs_info->fs_devices->missing_devices >
1767                      fs_info->num_tolerated_disk_barrier_failures &&
1768                     !(*flags & MS_RDONLY)) {
1769                         btrfs_warn(fs_info,
1770                                 "too many missing devices, writeable remount is not allowed");
1771                         ret = -EACCES;
1772                         goto restore;
1773                 }
1774
1775                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1776                         ret = -EINVAL;
1777                         goto restore;
1778                 }
1779
1780                 ret = btrfs_cleanup_fs_roots(fs_info);
1781                 if (ret)
1782                         goto restore;
1783
1784                 /* recover relocation */
1785                 mutex_lock(&fs_info->cleaner_mutex);
1786                 ret = btrfs_recover_relocation(root);
1787                 mutex_unlock(&fs_info->cleaner_mutex);
1788                 if (ret)
1789                         goto restore;
1790
1791                 ret = btrfs_resume_balance_async(fs_info);
1792                 if (ret)
1793                         goto restore;
1794
1795                 ret = btrfs_resume_dev_replace_async(fs_info);
1796                 if (ret) {
1797                         btrfs_warn(fs_info, "failed to resume dev_replace");
1798                         goto restore;
1799                 }
1800
1801                 if (!fs_info->uuid_root) {
1802                         btrfs_info(fs_info, "creating UUID tree");
1803                         ret = btrfs_create_uuid_tree(fs_info);
1804                         if (ret) {
1805                                 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1806                                 goto restore;
1807                         }
1808                 }
1809                 sb->s_flags &= ~MS_RDONLY;
1810         }
1811 out:
1812         wake_up_process(fs_info->transaction_kthread);
1813         btrfs_remount_cleanup(fs_info, old_opts);
1814         return 0;
1815
1816 restore:
1817         /* We've hit an error - don't reset MS_RDONLY */
1818         if (sb->s_flags & MS_RDONLY)
1819                 old_flags |= MS_RDONLY;
1820         sb->s_flags = old_flags;
1821         fs_info->mount_opt = old_opts;
1822         fs_info->compress_type = old_compress_type;
1823         fs_info->max_inline = old_max_inline;
1824         mutex_lock(&fs_info->chunk_mutex);
1825         fs_info->alloc_start = old_alloc_start;
1826         mutex_unlock(&fs_info->chunk_mutex);
1827         btrfs_resize_thread_pool(fs_info,
1828                 old_thread_pool_size, fs_info->thread_pool_size);
1829         fs_info->metadata_ratio = old_metadata_ratio;
1830         btrfs_remount_cleanup(fs_info, old_opts);
1831         return ret;
1832 }
1833
1834 /* Used to sort the devices by max_avail(descending sort) */
1835 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1836                                        const void *dev_info2)
1837 {
1838         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1839             ((struct btrfs_device_info *)dev_info2)->max_avail)
1840                 return -1;
1841         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1842                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1843                 return 1;
1844         else
1845         return 0;
1846 }
1847
1848 /*
1849  * sort the devices by max_avail, in which max free extent size of each device
1850  * is stored.(Descending Sort)
1851  */
1852 static inline void btrfs_descending_sort_devices(
1853                                         struct btrfs_device_info *devices,
1854                                         size_t nr_devices)
1855 {
1856         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1857              btrfs_cmp_device_free_bytes, NULL);
1858 }
1859
1860 /*
1861  * The helper to calc the free space on the devices that can be used to store
1862  * file data.
1863  */
1864 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1865 {
1866         struct btrfs_fs_info *fs_info = root->fs_info;
1867         struct btrfs_device_info *devices_info;
1868         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1869         struct btrfs_device *device;
1870         u64 skip_space;
1871         u64 type;
1872         u64 avail_space;
1873         u64 used_space;
1874         u64 min_stripe_size;
1875         int min_stripes = 1, num_stripes = 1;
1876         int i = 0, nr_devices;
1877         int ret;
1878
1879         /*
1880          * We aren't under the device list lock, so this is racey-ish, but good
1881          * enough for our purposes.
1882          */
1883         nr_devices = fs_info->fs_devices->open_devices;
1884         if (!nr_devices) {
1885                 smp_mb();
1886                 nr_devices = fs_info->fs_devices->open_devices;
1887                 ASSERT(nr_devices);
1888                 if (!nr_devices) {
1889                         *free_bytes = 0;
1890                         return 0;
1891                 }
1892         }
1893
1894         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1895                                GFP_NOFS);
1896         if (!devices_info)
1897                 return -ENOMEM;
1898
1899         /* calc min stripe number for data space alloction */
1900         type = btrfs_get_alloc_profile(root, 1);
1901         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1902                 min_stripes = 2;
1903                 num_stripes = nr_devices;
1904         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1905                 min_stripes = 2;
1906                 num_stripes = 2;
1907         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1908                 min_stripes = 4;
1909                 num_stripes = 4;
1910         }
1911
1912         if (type & BTRFS_BLOCK_GROUP_DUP)
1913                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1914         else
1915                 min_stripe_size = BTRFS_STRIPE_LEN;
1916
1917         if (fs_info->alloc_start)
1918                 mutex_lock(&fs_devices->device_list_mutex);
1919         rcu_read_lock();
1920         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1921                 if (!device->in_fs_metadata || !device->bdev ||
1922                     device->is_tgtdev_for_dev_replace)
1923                         continue;
1924
1925                 if (i >= nr_devices)
1926                         break;
1927
1928                 avail_space = device->total_bytes - device->bytes_used;
1929
1930                 /* align with stripe_len */
1931                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1932                 avail_space *= BTRFS_STRIPE_LEN;
1933
1934                 /*
1935                  * In order to avoid overwritting the superblock on the drive,
1936                  * btrfs starts at an offset of at least 1MB when doing chunk
1937                  * allocation.
1938                  */
1939                 skip_space = SZ_1M;
1940
1941                 /* user can set the offset in fs_info->alloc_start. */
1942                 if (fs_info->alloc_start &&
1943                     fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1944                     device->total_bytes) {
1945                         rcu_read_unlock();
1946                         skip_space = max(fs_info->alloc_start, skip_space);
1947
1948                         /*
1949                          * btrfs can not use the free space in
1950                          * [0, skip_space - 1], we must subtract it from the
1951                          * total. In order to implement it, we account the used
1952                          * space in this range first.
1953                          */
1954                         ret = btrfs_account_dev_extents_size(device, 0,
1955                                                              skip_space - 1,
1956                                                              &used_space);
1957                         if (ret) {
1958                                 kfree(devices_info);
1959                                 mutex_unlock(&fs_devices->device_list_mutex);
1960                                 return ret;
1961                         }
1962
1963                         rcu_read_lock();
1964
1965                         /* calc the free space in [0, skip_space - 1] */
1966                         skip_space -= used_space;
1967                 }
1968
1969                 /*
1970                  * we can use the free space in [0, skip_space - 1], subtract
1971                  * it from the total.
1972                  */
1973                 if (avail_space && avail_space >= skip_space)
1974                         avail_space -= skip_space;
1975                 else
1976                         avail_space = 0;
1977
1978                 if (avail_space < min_stripe_size)
1979                         continue;
1980
1981                 devices_info[i].dev = device;
1982                 devices_info[i].max_avail = avail_space;
1983
1984                 i++;
1985         }
1986         rcu_read_unlock();
1987         if (fs_info->alloc_start)
1988                 mutex_unlock(&fs_devices->device_list_mutex);
1989
1990         nr_devices = i;
1991
1992         btrfs_descending_sort_devices(devices_info, nr_devices);
1993
1994         i = nr_devices - 1;
1995         avail_space = 0;
1996         while (nr_devices >= min_stripes) {
1997                 if (num_stripes > nr_devices)
1998                         num_stripes = nr_devices;
1999
2000                 if (devices_info[i].max_avail >= min_stripe_size) {
2001                         int j;
2002                         u64 alloc_size;
2003
2004                         avail_space += devices_info[i].max_avail * num_stripes;
2005                         alloc_size = devices_info[i].max_avail;
2006                         for (j = i + 1 - num_stripes; j <= i; j++)
2007                                 devices_info[j].max_avail -= alloc_size;
2008                 }
2009                 i--;
2010                 nr_devices--;
2011         }
2012
2013         kfree(devices_info);
2014         *free_bytes = avail_space;
2015         return 0;
2016 }
2017
2018 /*
2019  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2020  *
2021  * If there's a redundant raid level at DATA block groups, use the respective
2022  * multiplier to scale the sizes.
2023  *
2024  * Unused device space usage is based on simulating the chunk allocator
2025  * algorithm that respects the device sizes, order of allocations and the
2026  * 'alloc_start' value, this is a close approximation of the actual use but
2027  * there are other factors that may change the result (like a new metadata
2028  * chunk).
2029  *
2030  * If metadata is exhausted, f_bavail will be 0.
2031  *
2032  * FIXME: not accurate for mixed block groups, total and free/used are ok,
2033  * available appears slightly larger.
2034  */
2035 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2036 {
2037         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2038         struct btrfs_super_block *disk_super = fs_info->super_copy;
2039         struct list_head *head = &fs_info->space_info;
2040         struct btrfs_space_info *found;
2041         u64 total_used = 0;
2042         u64 total_free_data = 0;
2043         u64 total_free_meta = 0;
2044         int bits = dentry->d_sb->s_blocksize_bits;
2045         __be32 *fsid = (__be32 *)fs_info->fsid;
2046         unsigned factor = 1;
2047         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2048         int ret;
2049         u64 thresh = 0;
2050         int mixed = 0;
2051
2052         /*
2053          * holding chunk_mutex to avoid allocating new chunks, holding
2054          * device_list_mutex to avoid the device being removed
2055          */
2056         rcu_read_lock();
2057         list_for_each_entry_rcu(found, head, list) {
2058                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2059                         int i;
2060
2061                         total_free_data += found->disk_total - found->disk_used;
2062                         total_free_data -=
2063                                 btrfs_account_ro_block_groups_free_space(found);
2064
2065                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2066                                 if (!list_empty(&found->block_groups[i])) {
2067                                         switch (i) {
2068                                         case BTRFS_RAID_DUP:
2069                                         case BTRFS_RAID_RAID1:
2070                                         case BTRFS_RAID_RAID10:
2071                                                 factor = 2;
2072                                         }
2073                                 }
2074                         }
2075                 }
2076
2077                 /*
2078                  * Metadata in mixed block goup profiles are accounted in data
2079                  */
2080                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2081                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2082                                 mixed = 1;
2083                         else
2084                                 total_free_meta += found->disk_total -
2085                                         found->disk_used;
2086                 }
2087
2088                 total_used += found->disk_used;
2089         }
2090
2091         rcu_read_unlock();
2092
2093         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2094         buf->f_blocks >>= bits;
2095         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2096
2097         /* Account global block reserve as used, it's in logical size already */
2098         spin_lock(&block_rsv->lock);
2099         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2100         if (buf->f_bfree >= block_rsv->size >> bits)
2101                 buf->f_bfree -= block_rsv->size >> bits;
2102         else
2103                 buf->f_bfree = 0;
2104         spin_unlock(&block_rsv->lock);
2105
2106         buf->f_bavail = div_u64(total_free_data, factor);
2107         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2108         if (ret)
2109                 return ret;
2110         buf->f_bavail += div_u64(total_free_data, factor);
2111         buf->f_bavail = buf->f_bavail >> bits;
2112
2113         /*
2114          * We calculate the remaining metadata space minus global reserve. If
2115          * this is (supposedly) smaller than zero, there's no space. But this
2116          * does not hold in practice, the exhausted state happens where's still
2117          * some positive delta. So we apply some guesswork and compare the
2118          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2119          *
2120          * We probably cannot calculate the exact threshold value because this
2121          * depends on the internal reservations requested by various
2122          * operations, so some operations that consume a few metadata will
2123          * succeed even if the Avail is zero. But this is better than the other
2124          * way around.
2125          */
2126         thresh = 4 * 1024 * 1024;
2127
2128         if (!mixed && total_free_meta - thresh < block_rsv->size)
2129                 buf->f_bavail = 0;
2130
2131         buf->f_type = BTRFS_SUPER_MAGIC;
2132         buf->f_bsize = dentry->d_sb->s_blocksize;
2133         buf->f_namelen = BTRFS_NAME_LEN;
2134
2135         /* We treat it as constant endianness (it doesn't matter _which_)
2136            because we want the fsid to come out the same whether mounted
2137            on a big-endian or little-endian host */
2138         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2139         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2140         /* Mask in the root object ID too, to disambiguate subvols */
2141         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2142         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2143
2144         return 0;
2145 }
2146
2147 static void btrfs_kill_super(struct super_block *sb)
2148 {
2149         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2150         kill_anon_super(sb);
2151         free_fs_info(fs_info);
2152 }
2153
2154 static struct file_system_type btrfs_fs_type = {
2155         .owner          = THIS_MODULE,
2156         .name           = "btrfs",
2157         .mount          = btrfs_mount,
2158         .kill_sb        = btrfs_kill_super,
2159         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2160 };
2161 MODULE_ALIAS_FS("btrfs");
2162
2163 static int btrfs_control_open(struct inode *inode, struct file *file)
2164 {
2165         /*
2166          * The control file's private_data is used to hold the
2167          * transaction when it is started and is used to keep
2168          * track of whether a transaction is already in progress.
2169          */
2170         file->private_data = NULL;
2171         return 0;
2172 }
2173
2174 /*
2175  * used by btrfsctl to scan devices when no FS is mounted
2176  */
2177 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2178                                 unsigned long arg)
2179 {
2180         struct btrfs_ioctl_vol_args *vol;
2181         struct btrfs_fs_devices *fs_devices;
2182         int ret = -ENOTTY;
2183
2184         if (!capable(CAP_SYS_ADMIN))
2185                 return -EPERM;
2186
2187         vol = memdup_user((void __user *)arg, sizeof(*vol));
2188         if (IS_ERR(vol))
2189                 return PTR_ERR(vol);
2190
2191         switch (cmd) {
2192         case BTRFS_IOC_SCAN_DEV:
2193                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2194                                             &btrfs_fs_type, &fs_devices);
2195                 break;
2196         case BTRFS_IOC_DEVICES_READY:
2197                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2198                                             &btrfs_fs_type, &fs_devices);
2199                 if (ret)
2200                         break;
2201                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2202                 break;
2203         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2204                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2205                 break;
2206         }
2207
2208         kfree(vol);
2209         return ret;
2210 }
2211
2212 static int btrfs_freeze(struct super_block *sb)
2213 {
2214         struct btrfs_trans_handle *trans;
2215         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2216
2217         trans = btrfs_attach_transaction_barrier(root);
2218         if (IS_ERR(trans)) {
2219                 /* no transaction, don't bother */
2220                 if (PTR_ERR(trans) == -ENOENT)
2221                         return 0;
2222                 return PTR_ERR(trans);
2223         }
2224         return btrfs_commit_transaction(trans, root);
2225 }
2226
2227 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2228 {
2229         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2230         struct btrfs_fs_devices *cur_devices;
2231         struct btrfs_device *dev, *first_dev = NULL;
2232         struct list_head *head;
2233         struct rcu_string *name;
2234
2235         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2236         cur_devices = fs_info->fs_devices;
2237         while (cur_devices) {
2238                 head = &cur_devices->devices;
2239                 list_for_each_entry(dev, head, dev_list) {
2240                         if (dev->missing)
2241                                 continue;
2242                         if (!dev->name)
2243                                 continue;
2244                         if (!first_dev || dev->devid < first_dev->devid)
2245                                 first_dev = dev;
2246                 }
2247                 cur_devices = cur_devices->seed;
2248         }
2249
2250         if (first_dev) {
2251                 rcu_read_lock();
2252                 name = rcu_dereference(first_dev->name);
2253                 seq_escape(m, name->str, " \t\n\\");
2254                 rcu_read_unlock();
2255         } else {
2256                 WARN_ON(1);
2257         }
2258         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2259         return 0;
2260 }
2261
2262 static const struct super_operations btrfs_super_ops = {
2263         .drop_inode     = btrfs_drop_inode,
2264         .evict_inode    = btrfs_evict_inode,
2265         .put_super      = btrfs_put_super,
2266         .sync_fs        = btrfs_sync_fs,
2267         .show_options   = btrfs_show_options,
2268         .show_devname   = btrfs_show_devname,
2269         .write_inode    = btrfs_write_inode,
2270         .alloc_inode    = btrfs_alloc_inode,
2271         .destroy_inode  = btrfs_destroy_inode,
2272         .statfs         = btrfs_statfs,
2273         .remount_fs     = btrfs_remount,
2274         .freeze_fs      = btrfs_freeze,
2275 };
2276
2277 static const struct file_operations btrfs_ctl_fops = {
2278         .open = btrfs_control_open,
2279         .unlocked_ioctl  = btrfs_control_ioctl,
2280         .compat_ioctl = btrfs_control_ioctl,
2281         .owner   = THIS_MODULE,
2282         .llseek = noop_llseek,
2283 };
2284
2285 static struct miscdevice btrfs_misc = {
2286         .minor          = BTRFS_MINOR,
2287         .name           = "btrfs-control",
2288         .fops           = &btrfs_ctl_fops
2289 };
2290
2291 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2292 MODULE_ALIAS("devname:btrfs-control");
2293
2294 static int btrfs_interface_init(void)
2295 {
2296         return misc_register(&btrfs_misc);
2297 }
2298
2299 static void btrfs_interface_exit(void)
2300 {
2301         misc_deregister(&btrfs_misc);
2302 }
2303
2304 static void btrfs_print_mod_info(void)
2305 {
2306         printk(KERN_INFO "Btrfs loaded"
2307 #ifdef CONFIG_BTRFS_DEBUG
2308                         ", debug=on"
2309 #endif
2310 #ifdef CONFIG_BTRFS_ASSERT
2311                         ", assert=on"
2312 #endif
2313 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2314                         ", integrity-checker=on"
2315 #endif
2316                         "\n");
2317 }
2318
2319 static int btrfs_run_sanity_tests(void)
2320 {
2321         int ret;
2322
2323         ret = btrfs_init_test_fs();
2324         if (ret)
2325                 return ret;
2326
2327         ret = btrfs_test_free_space_cache();
2328         if (ret)
2329                 goto out;
2330         ret = btrfs_test_extent_buffer_operations();
2331         if (ret)
2332                 goto out;
2333         ret = btrfs_test_extent_io();
2334         if (ret)
2335                 goto out;
2336         ret = btrfs_test_inodes();
2337         if (ret)
2338                 goto out;
2339         ret = btrfs_test_qgroups();
2340         if (ret)
2341                 goto out;
2342         ret = btrfs_test_free_space_tree();
2343 out:
2344         btrfs_destroy_test_fs();
2345         return ret;
2346 }
2347
2348 static int __init init_btrfs_fs(void)
2349 {
2350         int err;
2351
2352         err = btrfs_hash_init();
2353         if (err)
2354                 return err;
2355
2356         btrfs_props_init();
2357
2358         err = btrfs_init_sysfs();
2359         if (err)
2360                 goto free_hash;
2361
2362         btrfs_init_compress();
2363
2364         err = btrfs_init_cachep();
2365         if (err)
2366                 goto free_compress;
2367
2368         err = extent_io_init();
2369         if (err)
2370                 goto free_cachep;
2371
2372         err = extent_map_init();
2373         if (err)
2374                 goto free_extent_io;
2375
2376         err = ordered_data_init();
2377         if (err)
2378                 goto free_extent_map;
2379
2380         err = btrfs_delayed_inode_init();
2381         if (err)
2382                 goto free_ordered_data;
2383
2384         err = btrfs_auto_defrag_init();
2385         if (err)
2386                 goto free_delayed_inode;
2387
2388         err = btrfs_delayed_ref_init();
2389         if (err)
2390                 goto free_auto_defrag;
2391
2392         err = btrfs_prelim_ref_init();
2393         if (err)
2394                 goto free_delayed_ref;
2395
2396         err = btrfs_end_io_wq_init();
2397         if (err)
2398                 goto free_prelim_ref;
2399
2400         err = btrfs_interface_init();
2401         if (err)
2402                 goto free_end_io_wq;
2403
2404         btrfs_init_lockdep();
2405
2406         btrfs_print_mod_info();
2407
2408         err = btrfs_run_sanity_tests();
2409         if (err)
2410                 goto unregister_ioctl;
2411
2412         err = register_filesystem(&btrfs_fs_type);
2413         if (err)
2414                 goto unregister_ioctl;
2415
2416         return 0;
2417
2418 unregister_ioctl:
2419         btrfs_interface_exit();
2420 free_end_io_wq:
2421         btrfs_end_io_wq_exit();
2422 free_prelim_ref:
2423         btrfs_prelim_ref_exit();
2424 free_delayed_ref:
2425         btrfs_delayed_ref_exit();
2426 free_auto_defrag:
2427         btrfs_auto_defrag_exit();
2428 free_delayed_inode:
2429         btrfs_delayed_inode_exit();
2430 free_ordered_data:
2431         ordered_data_exit();
2432 free_extent_map:
2433         extent_map_exit();
2434 free_extent_io:
2435         extent_io_exit();
2436 free_cachep:
2437         btrfs_destroy_cachep();
2438 free_compress:
2439         btrfs_exit_compress();
2440         btrfs_exit_sysfs();
2441 free_hash:
2442         btrfs_hash_exit();
2443         return err;
2444 }
2445
2446 static void __exit exit_btrfs_fs(void)
2447 {
2448         btrfs_destroy_cachep();
2449         btrfs_delayed_ref_exit();
2450         btrfs_auto_defrag_exit();
2451         btrfs_delayed_inode_exit();
2452         btrfs_prelim_ref_exit();
2453         ordered_data_exit();
2454         extent_map_exit();
2455         extent_io_exit();
2456         btrfs_interface_exit();
2457         btrfs_end_io_wq_exit();
2458         unregister_filesystem(&btrfs_fs_type);
2459         btrfs_exit_sysfs();
2460         btrfs_cleanup_fs_uuids();
2461         btrfs_exit_compress();
2462         btrfs_hash_exit();
2463 }
2464
2465 late_initcall(init_btrfs_fs);
2466 module_exit(exit_btrfs_fs)
2467
2468 MODULE_LICENSE("GPL");