fs/btrfs/super.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/fs.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/highmem.h>
  25 #include <linux/time.h>
  26 #include <linux/init.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mount.h>
  31 #include <linux/mpage.h>
  32 #include <linux/swap.h>
  33 #include <linux/writeback.h>
  34 #include <linux/statfs.h>
  35 #include <linux/compat.h>
  36 #include <linux/parser.h>
  37 #include <linux/ctype.h>
  38 #include <linux/namei.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/magic.h>
  41 #include <linux/slab.h>
  42 #include <linux/cleancache.h>
  43 #include <linux/ratelimit.h>
  44 #include <linux/btrfs.h>
  45 #include "delayed-inode.h"
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "hash.h"
  52 #include "props.h"
  53 #include "xattr.h"
  54 #include "volumes.h"
  55 #include "export.h"
  56 #include "compression.h"
  57 #include "rcu-string.h"
  58 #include "dev-replace.h"
  59 #include "free-space-cache.h"
  60 #include "backref.h"
  61 #include "tests/btrfs-tests.h"
  62
  63 #include "qgroup.h"
  64 #define CREATE_TRACE_POINTS
  65 #include <trace/events/btrfs.h>
  66
  67 static const struct super_operations btrfs_super_ops;
  68 static struct file_system_type btrfs_fs_type;
  69
  70 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  71
  72 const char *btrfs_decode_error(int errno)
  73 {
  74         char *errstr = "unknown";
  75
  76         switch (errno) {
  77         case -EIO:
  78                 errstr = "IO failure";
  79                 break;
  80         case -ENOMEM:
  81                 errstr = "Out of memory";
  82                 break;
  83         case -EROFS:
  84                 errstr = "Readonly filesystem";
  85                 break;
  86         case -EEXIST:
  87                 errstr = "Object already exists";
  88                 break;
  89         case -ENOSPC:
  90                 errstr = "No space left";
  91                 break;
  92         case -ENOENT:
  93                 errstr = "No such entry";
  94                 break;
  95         }
  96
  97         return errstr;
  98 }
  99
 100 /* btrfs handle error by forcing the filesystem readonly */
 101 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 102 {
 103         struct super_block *sb = fs_info->sb;
 104
 105         if (sb->s_flags & MS_RDONLY)
 106                 return;
 107
 108         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 109                 sb->s_flags |= MS_RDONLY;
 110                 btrfs_info(fs_info, "forced readonly");
 111                 /*
 112                  * Note that a running device replace operation is not
 113                  * canceled here although there is no way to update
 114                  * the progress. It would add the risk of a deadlock,
 115                  * therefore the canceling is omitted. The only penalty
 116                  * is that some I/O remains active until the procedure
 117                  * completes. The next time when the filesystem is
 118                  * mounted writeable again, the device replace
 119                  * operation continues.
 120                  */
 121         }
 122 }
 123
 124 /*
 125  * __btrfs_handle_fs_error decodes expected errors from the caller and
 126  * invokes the approciate error response.
 127  */
 128 __cold
 129 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 130                        unsigned int line, int errno, const char *fmt, ...)
 131 {
 132         struct super_block *sb = fs_info->sb;
 133 #ifdef CONFIG_PRINTK
 134         const char *errstr;
 135 #endif
 136
 137         /*
 138          * Special case: if the error is EROFS, and we're already
 139          * under MS_RDONLY, then it is safe here.
 140          */
 141         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 142                 return;
 143
 144 #ifdef CONFIG_PRINTK
 145         errstr = btrfs_decode_error(errno);
 146         if (fmt) {
 147                 struct va_format vaf;
 148                 va_list args;
 149
 150                 va_start(args, fmt);
 151                 vaf.fmt = fmt;
 152                 vaf.va = &args;
 153
 154                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 155                         sb->s_id, function, line, errno, errstr, &vaf);
 156                 va_end(args);
 157         } else {
 158                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 159                         sb->s_id, function, line, errno, errstr);
 160         }
 161 #endif
 162
 163         /*
 164          * Today we only save the error info to memory.  Long term we'll
 165          * also send it down to the disk
 166          */
 167         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 168
 169         /* Don't go through full error handling during mount */
 170         if (sb->s_flags & MS_BORN)
 171                 btrfs_handle_error(fs_info);
 172 }
 173
 174 #ifdef CONFIG_PRINTK
 175 static const char * const logtypes[] = {
 176         "emergency",
 177         "alert",
 178         "critical",
 179         "error",
 180         "warning",
 181         "notice",
 182         "info",
 183         "debug",
 184 };
 185
 186
 187 /*
 188  * Use one ratelimit state per log level so that a flood of less important
 189  * messages doesn't cause more important ones to be dropped.
 190  */
 191 static struct ratelimit_state printk_limits[] = {
 192         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 193         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 194         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 195         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 196         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 197         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 198         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 199         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 200 };
 201
 202 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 203 {
 204         struct super_block *sb = fs_info->sb;
 205         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
 206         struct va_format vaf;
 207         va_list args;
 208         int kern_level;
 209         const char *type = logtypes[4];
 210         struct ratelimit_state *ratelimit = &printk_limits[4];
 211
 212         va_start(args, fmt);
 213
 214         while ((kern_level = printk_get_level(fmt)) != 0) {
 215                 size_t size = printk_skip_level(fmt) - fmt;
 216
 217                 if (kern_level >= '0' && kern_level <= '7') {
 218                         memcpy(lvl, fmt,  size);
 219                         lvl[size] = '\0';
 220                         type = logtypes[kern_level - '0'];
 221                         ratelimit = &printk_limits[kern_level - '0'];
 222                 }
 223                 fmt += size;
 224         }
 225
 226         vaf.fmt = fmt;
 227         vaf.va = &args;
 228
 229         if (__ratelimit(ratelimit))
 230                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
 231
 232         va_end(args);
 233 }
 234 #endif
 235
 236 /*
 237  * We only mark the transaction aborted and then set the file system read-only.
 238  * This will prevent new transactions from starting or trying to join this
 239  * one.
 240  *
 241  * This means that error recovery at the call site is limited to freeing
 242  * any local memory allocations and passing the error code up without
 243  * further cleanup. The transaction should complete as it normally would
 244  * in the call path but will return -EIO.
 245  *
 246  * We'll complete the cleanup in btrfs_end_transaction and
 247  * btrfs_commit_transaction.
 248  */
 249 __cold
 250 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 251                                const char *function,
 252                                unsigned int line, int errno)
 253 {
 254         struct btrfs_fs_info *fs_info = trans->fs_info;
 255
 256         trans->aborted = errno;
 257         /* Nothing used. The other threads that have joined this
 258          * transaction may be able to continue. */
 259         if (!trans->dirty && list_empty(&trans->new_bgs)) {
 260                 const char *errstr;
 261
 262                 errstr = btrfs_decode_error(errno);
 263                 btrfs_warn(fs_info,
 264                            "%s:%d: Aborting unused transaction(%s).",
 265                            function, line, errstr);
 266                 return;
 267         }
 268         WRITE_ONCE(trans->transaction->aborted, errno);
 269         /* Wake up anybody who may be waiting on this transaction */
 270         wake_up(&fs_info->transaction_wait);
 271         wake_up(&fs_info->transaction_blocked_wait);
 272         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 273 }
 274 /*
 275  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 276  * issues an alert, and either panics or BUGs, depending on mount options.
 277  */
 278 __cold
 279 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 280                    unsigned int line, int errno, const char *fmt, ...)
 281 {
 282         char *s_id = "<unknown>";
 283         const char *errstr;
 284         struct va_format vaf = { .fmt = fmt };
 285         va_list args;
 286
 287         if (fs_info)
 288                 s_id = fs_info->sb->s_id;
 289
 290         va_start(args, fmt);
 291         vaf.va = &args;
 292
 293         errstr = btrfs_decode_error(errno);
 294         if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
 295                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 296                         s_id, function, line, &vaf, errno, errstr);
 297
 298         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 299                    function, line, &vaf, errno, errstr);
 300         va_end(args);
 301         /* Caller calls BUG() */
 302 }
 303
 304 static void btrfs_put_super(struct super_block *sb)
 305 {
 306         close_ctree(btrfs_sb(sb));
 307 }
 308
 309 enum {
 310         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 311         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 312         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 313         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 314         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 315         Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 316         Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 317         Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 318         Opt_skip_balance, Opt_check_integrity,
 319         Opt_check_integrity_including_extent_data,
 320         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 321         Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
 322         Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
 323         Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
 324         Opt_nologreplay, Opt_norecovery,
 325 #ifdef CONFIG_BTRFS_DEBUG
 326         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 327 #endif
 328         Opt_err,
 329 };
 330
 331 static const match_table_t tokens = {
 332         {Opt_degraded, "degraded"},
 333         {Opt_subvol, "subvol=%s"},
 334         {Opt_subvolid, "subvolid=%s"},
 335         {Opt_device, "device=%s"},
 336         {Opt_nodatasum, "nodatasum"},
 337         {Opt_datasum, "datasum"},
 338         {Opt_nodatacow, "nodatacow"},
 339         {Opt_datacow, "datacow"},
 340         {Opt_nobarrier, "nobarrier"},
 341         {Opt_barrier, "barrier"},
 342         {Opt_max_inline, "max_inline=%s"},
 343         {Opt_alloc_start, "alloc_start=%s"},
 344         {Opt_thread_pool, "thread_pool=%d"},
 345         {Opt_compress, "compress"},
 346         {Opt_compress_type, "compress=%s"},
 347         {Opt_compress_force, "compress-force"},
 348         {Opt_compress_force_type, "compress-force=%s"},
 349         {Opt_ssd, "ssd"},
 350         {Opt_ssd_spread, "ssd_spread"},
 351         {Opt_nossd, "nossd"},
 352         {Opt_acl, "acl"},
 353         {Opt_noacl, "noacl"},
 354         {Opt_notreelog, "notreelog"},
 355         {Opt_treelog, "treelog"},
 356         {Opt_nologreplay, "nologreplay"},
 357         {Opt_norecovery, "norecovery"},
 358         {Opt_flushoncommit, "flushoncommit"},
 359         {Opt_noflushoncommit, "noflushoncommit"},
 360         {Opt_ratio, "metadata_ratio=%d"},
 361         {Opt_discard, "discard"},
 362         {Opt_nodiscard, "nodiscard"},
 363         {Opt_space_cache, "space_cache"},
 364         {Opt_space_cache_version, "space_cache=%s"},
 365         {Opt_clear_cache, "clear_cache"},
 366         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 367         {Opt_enospc_debug, "enospc_debug"},
 368         {Opt_noenospc_debug, "noenospc_debug"},
 369         {Opt_subvolrootid, "subvolrootid=%d"},
 370         {Opt_defrag, "autodefrag"},
 371         {Opt_nodefrag, "noautodefrag"},
 372         {Opt_inode_cache, "inode_cache"},
 373         {Opt_noinode_cache, "noinode_cache"},
 374         {Opt_no_space_cache, "nospace_cache"},
 375         {Opt_recovery, "recovery"}, /* deprecated */
 376         {Opt_usebackuproot, "usebackuproot"},
 377         {Opt_skip_balance, "skip_balance"},
 378         {Opt_check_integrity, "check_int"},
 379         {Opt_check_integrity_including_extent_data, "check_int_data"},
 380         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 381         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 382         {Opt_fatal_errors, "fatal_errors=%s"},
 383         {Opt_commit_interval, "commit=%d"},
 384 #ifdef CONFIG_BTRFS_DEBUG
 385         {Opt_fragment_data, "fragment=data"},
 386         {Opt_fragment_metadata, "fragment=metadata"},
 387         {Opt_fragment_all, "fragment=all"},
 388 #endif
 389         {Opt_err, NULL},
 390 };
 391
 392 /*
 393  * Regular mount options parser.  Everything that is needed only when
 394  * reading in a new superblock is parsed here.
 395  * XXX JDM: This needs to be cleaned up for remount.
 396  */
 397 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 398                         unsigned long new_flags)
 399 {
 400         substring_t args[MAX_OPT_ARGS];
 401         char *p, *num, *orig = NULL;
 402         u64 cache_gen;
 403         int intarg;
 404         int ret = 0;
 405         char *compress_type;
 406         bool compress_force = false;
 407         enum btrfs_compression_type saved_compress_type;
 408         bool saved_compress_force;
 409         int no_compress = 0;
 410
 411         cache_gen = btrfs_super_cache_generation(info->super_copy);
 412         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 413                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 414         else if (cache_gen)
 415                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 416
 417         /*
 418          * Even the options are empty, we still need to do extra check
 419          * against new flags
 420          */
 421         if (!options)
 422                 goto check;
 423
 424         /*
 425          * strsep changes the string, duplicate it because parse_options
 426          * gets called twice
 427          */
 428         options = kstrdup(options, GFP_NOFS);
 429         if (!options)
 430                 return -ENOMEM;
 431
 432         orig = options;
 433
 434         while ((p = strsep(&options, ",")) != NULL) {
 435                 int token;
 436                 if (!*p)
 437                         continue;
 438
 439                 token = match_token(p, tokens, args);
 440                 switch (token) {
 441                 case Opt_degraded:
 442                         btrfs_info(info, "allowing degraded mounts");
 443                         btrfs_set_opt(info->mount_opt, DEGRADED);
 444                         break;
 445                 case Opt_subvol:
 446                 case Opt_subvolid:
 447                 case Opt_subvolrootid:
 448                 case Opt_device:
 449                         /*
 450                          * These are parsed by btrfs_parse_early_options
 451                          * and can be happily ignored here.
 452                          */
 453                         break;
 454                 case Opt_nodatasum:
 455                         btrfs_set_and_info(info, NODATASUM,
 456                                            "setting nodatasum");
 457                         break;
 458                 case Opt_datasum:
 459                         if (btrfs_test_opt(info, NODATASUM)) {
 460                                 if (btrfs_test_opt(info, NODATACOW))
 461                                         btrfs_info(info,
 462                                                    "setting datasum, datacow enabled");
 463                                 else
 464                                         btrfs_info(info, "setting datasum");
 465                         }
 466                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 467                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 468                         break;
 469                 case Opt_nodatacow:
 470                         if (!btrfs_test_opt(info, NODATACOW)) {
 471                                 if (!btrfs_test_opt(info, COMPRESS) ||
 472                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 473                                         btrfs_info(info,
 474                                                    "setting nodatacow, compression disabled");
 475                                 } else {
 476                                         btrfs_info(info, "setting nodatacow");
 477                                 }
 478                         }
 479                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 480                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 481                         btrfs_set_opt(info->mount_opt, NODATACOW);
 482                         btrfs_set_opt(info->mount_opt, NODATASUM);
 483                         break;
 484                 case Opt_datacow:
 485                         btrfs_clear_and_info(info, NODATACOW,
 486                                              "setting datacow");
 487                         break;
 488                 case Opt_compress_force:
 489                 case Opt_compress_force_type:
 490                         compress_force = true;
 491                         /* Fallthrough */
 492                 case Opt_compress:
 493                 case Opt_compress_type:
 494                         saved_compress_type = btrfs_test_opt(info,
 495                                                              COMPRESS) ?
 496                                 info->compress_type : BTRFS_COMPRESS_NONE;
 497                         saved_compress_force =
 498                                 btrfs_test_opt(info, FORCE_COMPRESS);
 499                         if (token == Opt_compress ||
 500                             token == Opt_compress_force ||
 501                             strcmp(args[0].from, "zlib") == 0) {
 502                                 compress_type = "zlib";
 503                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 504                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 505                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 506                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 507                                 no_compress = 0;
 508                         } else if (strcmp(args[0].from, "lzo") == 0) {
 509                                 compress_type = "lzo";
 510                                 info->compress_type = BTRFS_COMPRESS_LZO;
 511                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 512                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 513                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 514                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 515                                 no_compress = 0;
 516                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 517                                 compress_type = "no";
 518                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 519                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 520                                 compress_force = false;
 521                                 no_compress++;
 522                         } else {
 523                                 ret = -EINVAL;
 524                                 goto out;
 525                         }
 526
 527                         if (compress_force) {
 528                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 529                         } else {
 530                                 /*
 531                                  * If we remount from compress-force=xxx to
 532                                  * compress=xxx, we need clear FORCE_COMPRESS
 533                                  * flag, otherwise, there is no way for users
 534                                  * to disable forcible compression separately.
 535                                  */
 536                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 537                         }
 538                         if ((btrfs_test_opt(info, COMPRESS) &&
 539                              (info->compress_type != saved_compress_type ||
 540                               compress_force != saved_compress_force)) ||
 541                             (!btrfs_test_opt(info, COMPRESS) &&
 542                              no_compress == 1)) {
 543                                 btrfs_info(info, "%s %s compression",
 544                                            (compress_force) ? "force" : "use",
 545                                            compress_type);
 546                         }
 547                         compress_force = false;
 548                         break;
 549                 case Opt_ssd:
 550                         btrfs_set_and_info(info, SSD,
 551                                            "use ssd allocation scheme");
 552                         btrfs_clear_opt(info->mount_opt, NOSSD);
 553                         break;
 554                 case Opt_ssd_spread:
 555                         btrfs_set_and_info(info, SSD_SPREAD,
 556                                            "use spread ssd allocation scheme");
 557                         btrfs_set_opt(info->mount_opt, SSD);
 558                         btrfs_clear_opt(info->mount_opt, NOSSD);
 559                         break;
 560                 case Opt_nossd:
 561                         btrfs_set_and_info(info, NOSSD,
 562                                              "not using ssd allocation scheme");
 563                         btrfs_clear_opt(info->mount_opt, SSD);
 564                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
 565                         break;
 566                 case Opt_barrier:
 567                         btrfs_clear_and_info(info, NOBARRIER,
 568                                              "turning on barriers");
 569                         break;
 570                 case Opt_nobarrier:
 571                         btrfs_set_and_info(info, NOBARRIER,
 572                                            "turning off barriers");
 573                         break;
 574                 case Opt_thread_pool:
 575                         ret = match_int(&args[0], &intarg);
 576                         if (ret) {
 577                                 goto out;
 578                         } else if (intarg > 0) {
 579                                 info->thread_pool_size = intarg;
 580                         } else {
 581                                 ret = -EINVAL;
 582                                 goto out;
 583                         }
 584                         break;
 585                 case Opt_max_inline:
 586                         num = match_strdup(&args[0]);
 587                         if (num) {
 588                                 info->max_inline = memparse(num, NULL);
 589                                 kfree(num);
 590
 591                                 if (info->max_inline) {
 592                                         info->max_inline = min_t(u64,
 593                                                 info->max_inline,
 594                                                 info->sectorsize);
 595                                 }
 596                                 btrfs_info(info, "max_inline at %llu",
 597                                            info->max_inline);
 598                         } else {
 599                                 ret = -ENOMEM;
 600                                 goto out;
 601                         }
 602                         break;
 603                 case Opt_alloc_start:
 604                         btrfs_info(info,
 605                                 "option alloc_start is obsolete, ignored");
 606                         break;
 607                 case Opt_acl:
 608 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 609                         info->sb->s_flags |= MS_POSIXACL;
 610                         break;
 611 #else
 612                         btrfs_err(info, "support for ACL not compiled in!");
 613                         ret = -EINVAL;
 614                         goto out;
 615 #endif
 616                 case Opt_noacl:
 617                         info->sb->s_flags &= ~MS_POSIXACL;
 618                         break;
 619                 case Opt_notreelog:
 620                         btrfs_set_and_info(info, NOTREELOG,
 621                                            "disabling tree log");
 622                         break;
 623                 case Opt_treelog:
 624                         btrfs_clear_and_info(info, NOTREELOG,
 625                                              "enabling tree log");
 626                         break;
 627                 case Opt_norecovery:
 628                 case Opt_nologreplay:
 629                         btrfs_set_and_info(info, NOLOGREPLAY,
 630                                            "disabling log replay at mount time");
 631                         break;
 632                 case Opt_flushoncommit:
 633                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 634                                            "turning on flush-on-commit");
 635                         break;
 636                 case Opt_noflushoncommit:
 637                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 638                                              "turning off flush-on-commit");
 639                         break;
 640                 case Opt_ratio:
 641                         ret = match_int(&args[0], &intarg);
 642                         if (ret) {
 643                                 goto out;
 644                         } else if (intarg >= 0) {
 645                                 info->metadata_ratio = intarg;
 646                                 btrfs_info(info, "metadata ratio %d",
 647                                            info->metadata_ratio);
 648                         } else {
 649                                 ret = -EINVAL;
 650                                 goto out;
 651                         }
 652                         break;
 653                 case Opt_discard:
 654                         btrfs_set_and_info(info, DISCARD,
 655                                            "turning on discard");
 656                         break;
 657                 case Opt_nodiscard:
 658                         btrfs_clear_and_info(info, DISCARD,
 659                                              "turning off discard");
 660                         break;
 661                 case Opt_space_cache:
 662                 case Opt_space_cache_version:
 663                         if (token == Opt_space_cache ||
 664                             strcmp(args[0].from, "v1") == 0) {
 665                                 btrfs_clear_opt(info->mount_opt,
 666                                                 FREE_SPACE_TREE);
 667                                 btrfs_set_and_info(info, SPACE_CACHE,
 668                                            "enabling disk space caching");
 669                         } else if (strcmp(args[0].from, "v2") == 0) {
 670                                 btrfs_clear_opt(info->mount_opt,
 671                                                 SPACE_CACHE);
 672                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 673                                                    "enabling free space tree");
 674                         } else {
 675                                 ret = -EINVAL;
 676                                 goto out;
 677                         }
 678                         break;
 679                 case Opt_rescan_uuid_tree:
 680                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 681                         break;
 682                 case Opt_no_space_cache:
 683                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 684                                 btrfs_clear_and_info(info, SPACE_CACHE,
 685                                              "disabling disk space caching");
 686                         }
 687                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 688                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 689                                              "disabling free space tree");
 690                         }
 691                         break;
 692                 case Opt_inode_cache:
 693                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 694                                            "enabling inode map caching");
 695                         break;
 696                 case Opt_noinode_cache:
 697                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 698                                              "disabling inode map caching");
 699                         break;
 700                 case Opt_clear_cache:
 701                         btrfs_set_and_info(info, CLEAR_CACHE,
 702                                            "force clearing of disk cache");
 703                         break;
 704                 case Opt_user_subvol_rm_allowed:
 705                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 706                         break;
 707                 case Opt_enospc_debug:
 708                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 709                         break;
 710                 case Opt_noenospc_debug:
 711                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 712                         break;
 713                 case Opt_defrag:
 714                         btrfs_set_and_info(info, AUTO_DEFRAG,
 715                                            "enabling auto defrag");
 716                         break;
 717                 case Opt_nodefrag:
 718                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 719                                              "disabling auto defrag");
 720                         break;
 721                 case Opt_recovery:
 722                         btrfs_warn(info,
 723                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 724                 case Opt_usebackuproot:
 725                         btrfs_info(info,
 726                                    "trying to use backup root at mount time");
 727                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 728                         break;
 729                 case Opt_skip_balance:
 730                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 731                         break;
 732 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 733                 case Opt_check_integrity_including_extent_data:
 734                         btrfs_info(info,
 735                                    "enabling check integrity including extent data");
 736                         btrfs_set_opt(info->mount_opt,
 737                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 738                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 739                         break;
 740                 case Opt_check_integrity:
 741                         btrfs_info(info, "enabling check integrity");
 742                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 743                         break;
 744                 case Opt_check_integrity_print_mask:
 745                         ret = match_int(&args[0], &intarg);
 746                         if (ret) {
 747                                 goto out;
 748                         } else if (intarg >= 0) {
 749                                 info->check_integrity_print_mask = intarg;
 750                                 btrfs_info(info,
 751                                            "check_integrity_print_mask 0x%x",
 752                                            info->check_integrity_print_mask);
 753                         } else {
 754                                 ret = -EINVAL;
 755                                 goto out;
 756                         }
 757                         break;
 758 #else
 759                 case Opt_check_integrity_including_extent_data:
 760                 case Opt_check_integrity:
 761                 case Opt_check_integrity_print_mask:
 762                         btrfs_err(info,
 763                                   "support for check_integrity* not compiled in!");
 764                         ret = -EINVAL;
 765                         goto out;
 766 #endif
 767                 case Opt_fatal_errors:
 768                         if (strcmp(args[0].from, "panic") == 0)
 769                                 btrfs_set_opt(info->mount_opt,
 770                                               PANIC_ON_FATAL_ERROR);
 771                         else if (strcmp(args[0].from, "bug") == 0)
 772                                 btrfs_clear_opt(info->mount_opt,
 773                                               PANIC_ON_FATAL_ERROR);
 774                         else {
 775                                 ret = -EINVAL;
 776                                 goto out;
 777                         }
 778                         break;
 779                 case Opt_commit_interval:
 780                         intarg = 0;
 781                         ret = match_int(&args[0], &intarg);
 782                         if (ret < 0) {
 783                                 btrfs_err(info, "invalid commit interval");
 784                                 ret = -EINVAL;
 785                                 goto out;
 786                         }
 787                         if (intarg > 0) {
 788                                 if (intarg > 300) {
 789                                         btrfs_warn(info,
 790                                                 "excessive commit interval %d",
 791                                                 intarg);
 792                                 }
 793                                 info->commit_interval = intarg;
 794                         } else {
 795                                 btrfs_info(info,
 796                                            "using default commit interval %ds",
 797                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 798                                 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 799                         }
 800                         break;
 801 #ifdef CONFIG_BTRFS_DEBUG
 802                 case Opt_fragment_all:
 803                         btrfs_info(info, "fragmenting all space");
 804                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 805                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 806                         break;
 807                 case Opt_fragment_metadata:
 808                         btrfs_info(info, "fragmenting metadata");
 809                         btrfs_set_opt(info->mount_opt,
 810                                       FRAGMENT_METADATA);
 811                         break;
 812                 case Opt_fragment_data:
 813                         btrfs_info(info, "fragmenting data");
 814                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 815                         break;
 816 #endif
 817                 case Opt_err:
 818                         btrfs_info(info, "unrecognized mount option '%s'", p);
 819                         ret = -EINVAL;
 820                         goto out;
 821                 default:
 822                         break;
 823                 }
 824         }
 825 check:
 826         /*
 827          * Extra check for current option against current flag
 828          */
 829         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
 830                 btrfs_err(info,
 831                           "nologreplay must be used with ro mount option");
 832                 ret = -EINVAL;
 833         }
 834 out:
 835         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 836             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 837             !btrfs_test_opt(info, CLEAR_CACHE)) {
 838                 btrfs_err(info, "cannot disable free space tree");
 839                 ret = -EINVAL;
 840
 841         }
 842         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 843                 btrfs_info(info, "disk space caching is enabled");
 844         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 845                 btrfs_info(info, "using free space tree");
 846         kfree(orig);
 847         return ret;
 848 }
 849
 850 /*
 851  * Parse mount options that are required early in the mount process.
 852  *
 853  * All other options will be parsed on much later in the mount process and
 854  * only when we need to allocate a new super block.
 855  */
 856 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 857                 void *holder, char **subvol_name, u64 *subvol_objectid,
 858                 struct btrfs_fs_devices **fs_devices)
 859 {
 860         substring_t args[MAX_OPT_ARGS];
 861         char *device_name, *opts, *orig, *p;
 862         char *num = NULL;
 863         int error = 0;
 864
 865         if (!options)
 866                 return 0;
 867
 868         /*
 869          * strsep changes the string, duplicate it because parse_options
 870          * gets called twice
 871          */
 872         opts = kstrdup(options, GFP_KERNEL);
 873         if (!opts)
 874                 return -ENOMEM;
 875         orig = opts;
 876
 877         while ((p = strsep(&opts, ",")) != NULL) {
 878                 int token;
 879                 if (!*p)
 880                         continue;
 881
 882                 token = match_token(p, tokens, args);
 883                 switch (token) {
 884                 case Opt_subvol:
 885                         kfree(*subvol_name);
 886                         *subvol_name = match_strdup(&args[0]);
 887                         if (!*subvol_name) {
 888                                 error = -ENOMEM;
 889                                 goto out;
 890                         }
 891                         break;
 892                 case Opt_subvolid:
 893                         num = match_strdup(&args[0]);
 894                         if (num) {
 895                                 *subvol_objectid = memparse(num, NULL);
 896                                 kfree(num);
 897                                 /* we want the original fs_tree */
 898                                 if (!*subvol_objectid)
 899                                         *subvol_objectid =
 900                                                 BTRFS_FS_TREE_OBJECTID;
 901                         } else {
 902                                 error = -EINVAL;
 903                                 goto out;
 904                         }
 905                         break;
 906                 case Opt_subvolrootid:
 907                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
 908                         break;
 909                 case Opt_device:
 910                         device_name = match_strdup(&args[0]);
 911                         if (!device_name) {
 912                                 error = -ENOMEM;
 913                                 goto out;
 914                         }
 915                         error = btrfs_scan_one_device(device_name,
 916                                         flags, holder, fs_devices);
 917                         kfree(device_name);
 918                         if (error)
 919                                 goto out;
 920                         break;
 921                 default:
 922                         break;
 923                 }
 924         }
 925
 926 out:
 927         kfree(orig);
 928         return error;
 929 }
 930
 931 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 932                                            u64 subvol_objectid)
 933 {
 934         struct btrfs_root *root = fs_info->tree_root;
 935         struct btrfs_root *fs_root;
 936         struct btrfs_root_ref *root_ref;
 937         struct btrfs_inode_ref *inode_ref;
 938         struct btrfs_key key;
 939         struct btrfs_path *path = NULL;
 940         char *name = NULL, *ptr;
 941         u64 dirid;
 942         int len;
 943         int ret;
 944
 945         path = btrfs_alloc_path();
 946         if (!path) {
 947                 ret = -ENOMEM;
 948                 goto err;
 949         }
 950         path->leave_spinning = 1;
 951
 952         name = kmalloc(PATH_MAX, GFP_NOFS);
 953         if (!name) {
 954                 ret = -ENOMEM;
 955                 goto err;
 956         }
 957         ptr = name + PATH_MAX - 1;
 958         ptr[0] = '\0';
 959
 960         /*
 961          * Walk up the subvolume trees in the tree of tree roots by root
 962          * backrefs until we hit the top-level subvolume.
 963          */
 964         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 965                 key.objectid = subvol_objectid;
 966                 key.type = BTRFS_ROOT_BACKREF_KEY;
 967                 key.offset = (u64)-1;
 968
 969                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 970                 if (ret < 0) {
 971                         goto err;
 972                 } else if (ret > 0) {
 973                         ret = btrfs_previous_item(root, path, subvol_objectid,
 974                                                   BTRFS_ROOT_BACKREF_KEY);
 975                         if (ret < 0) {
 976                                 goto err;
 977                         } else if (ret > 0) {
 978                                 ret = -ENOENT;
 979                                 goto err;
 980                         }
 981                 }
 982
 983                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 984                 subvol_objectid = key.offset;
 985
 986                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 987                                           struct btrfs_root_ref);
 988                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
 989                 ptr -= len + 1;
 990                 if (ptr < name) {
 991                         ret = -ENAMETOOLONG;
 992                         goto err;
 993                 }
 994                 read_extent_buffer(path->nodes[0], ptr + 1,
 995                                    (unsigned long)(root_ref + 1), len);
 996                 ptr[0] = '/';
 997                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
 998                 btrfs_release_path(path);
 999
1000                 key.objectid = subvol_objectid;
1001                 key.type = BTRFS_ROOT_ITEM_KEY;
1002                 key.offset = (u64)-1;
1003                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1004                 if (IS_ERR(fs_root)) {
1005                         ret = PTR_ERR(fs_root);
1006                         goto err;
1007                 }
1008
1009                 /*
1010                  * Walk up the filesystem tree by inode refs until we hit the
1011                  * root directory.
1012                  */
1013                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1014                         key.objectid = dirid;
1015                         key.type = BTRFS_INODE_REF_KEY;
1016                         key.offset = (u64)-1;
1017
1018                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1019                         if (ret < 0) {
1020                                 goto err;
1021                         } else if (ret > 0) {
1022                                 ret = btrfs_previous_item(fs_root, path, dirid,
1023                                                           BTRFS_INODE_REF_KEY);
1024                                 if (ret < 0) {
1025                                         goto err;
1026                                 } else if (ret > 0) {
1027                                         ret = -ENOENT;
1028                                         goto err;
1029                                 }
1030                         }
1031
1032                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1033                         dirid = key.offset;
1034
1035                         inode_ref = btrfs_item_ptr(path->nodes[0],
1036                                                    path->slots[0],
1037                                                    struct btrfs_inode_ref);
1038                         len = btrfs_inode_ref_name_len(path->nodes[0],
1039                                                        inode_ref);
1040                         ptr -= len + 1;
1041                         if (ptr < name) {
1042                                 ret = -ENAMETOOLONG;
1043                                 goto err;
1044                         }
1045                         read_extent_buffer(path->nodes[0], ptr + 1,
1046                                            (unsigned long)(inode_ref + 1), len);
1047                         ptr[0] = '/';
1048                         btrfs_release_path(path);
1049                 }
1050         }
1051
1052         btrfs_free_path(path);
1053         if (ptr == name + PATH_MAX - 1) {
1054                 name[0] = '/';
1055                 name[1] = '\0';
1056         } else {
1057                 memmove(name, ptr, name + PATH_MAX - ptr);
1058         }
1059         return name;
1060
1061 err:
1062         btrfs_free_path(path);
1063         kfree(name);
1064         return ERR_PTR(ret);
1065 }
1066
1067 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1068 {
1069         struct btrfs_root *root = fs_info->tree_root;
1070         struct btrfs_dir_item *di;
1071         struct btrfs_path *path;
1072         struct btrfs_key location;
1073         u64 dir_id;
1074
1075         path = btrfs_alloc_path();
1076         if (!path)
1077                 return -ENOMEM;
1078         path->leave_spinning = 1;
1079
1080         /*
1081          * Find the "default" dir item which points to the root item that we
1082          * will mount by default if we haven't been given a specific subvolume
1083          * to mount.
1084          */
1085         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1086         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1087         if (IS_ERR(di)) {
1088                 btrfs_free_path(path);
1089                 return PTR_ERR(di);
1090         }
1091         if (!di) {
1092                 /*
1093                  * Ok the default dir item isn't there.  This is weird since
1094                  * it's always been there, but don't freak out, just try and
1095                  * mount the top-level subvolume.
1096                  */
1097                 btrfs_free_path(path);
1098                 *objectid = BTRFS_FS_TREE_OBJECTID;
1099                 return 0;
1100         }
1101
1102         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1103         btrfs_free_path(path);
1104         *objectid = location.objectid;
1105         return 0;
1106 }
1107
1108 static int btrfs_fill_super(struct super_block *sb,
1109                             struct btrfs_fs_devices *fs_devices,
1110                             void *data)
1111 {
1112         struct inode *inode;
1113         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1114         struct btrfs_key key;
1115         int err;
1116
1117         sb->s_maxbytes = MAX_LFS_FILESIZE;
1118         sb->s_magic = BTRFS_SUPER_MAGIC;
1119         sb->s_op = &btrfs_super_ops;
1120         sb->s_d_op = &btrfs_dentry_operations;
1121         sb->s_export_op = &btrfs_export_ops;
1122         sb->s_xattr = btrfs_xattr_handlers;
1123         sb->s_time_gran = 1;
1124 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1125         sb->s_flags |= MS_POSIXACL;
1126 #endif
1127         sb->s_flags |= MS_I_VERSION;
1128         sb->s_iflags |= SB_I_CGROUPWB;
1129
1130         err = super_setup_bdi(sb);
1131         if (err) {
1132                 btrfs_err(fs_info, "super_setup_bdi failed");
1133                 return err;
1134         }
1135
1136         err = open_ctree(sb, fs_devices, (char *)data);
1137         if (err) {
1138                 btrfs_err(fs_info, "open_ctree failed");
1139                 return err;
1140         }
1141
1142         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1143         key.type = BTRFS_INODE_ITEM_KEY;
1144         key.offset = 0;
1145         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1146         if (IS_ERR(inode)) {
1147                 err = PTR_ERR(inode);
1148                 goto fail_close;
1149         }
1150
1151         sb->s_root = d_make_root(inode);
1152         if (!sb->s_root) {
1153                 err = -ENOMEM;
1154                 goto fail_close;
1155         }
1156
1157         save_mount_options(sb, data);
1158         cleancache_init_fs(sb);
1159         sb->s_flags |= MS_ACTIVE;
1160         return 0;
1161
1162 fail_close:
1163         close_ctree(fs_info);
1164         return err;
1165 }
1166
1167 int btrfs_sync_fs(struct super_block *sb, int wait)
1168 {
1169         struct btrfs_trans_handle *trans;
1170         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1171         struct btrfs_root *root = fs_info->tree_root;
1172
1173         trace_btrfs_sync_fs(fs_info, wait);
1174
1175         if (!wait) {
1176                 filemap_flush(fs_info->btree_inode->i_mapping);
1177                 return 0;
1178         }
1179
1180         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1181
1182         trans = btrfs_attach_transaction_barrier(root);
1183         if (IS_ERR(trans)) {
1184                 /* no transaction, don't bother */
1185                 if (PTR_ERR(trans) == -ENOENT) {
1186                         /*
1187                          * Exit unless we have some pending changes
1188                          * that need to go through commit
1189                          */
1190                         if (fs_info->pending_changes == 0)
1191                                 return 0;
1192                         /*
1193                          * A non-blocking test if the fs is frozen. We must not
1194                          * start a new transaction here otherwise a deadlock
1195                          * happens. The pending operations are delayed to the
1196                          * next commit after thawing.
1197                          */
1198                         if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1199                                 __sb_end_write(sb, SB_FREEZE_WRITE);
1200                         else
1201                                 return 0;
1202                         trans = btrfs_start_transaction(root, 0);
1203                 }
1204                 if (IS_ERR(trans))
1205                         return PTR_ERR(trans);
1206         }
1207         return btrfs_commit_transaction(trans);
1208 }
1209
1210 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1211 {
1212         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1213         char *compress_type;
1214
1215         if (btrfs_test_opt(info, DEGRADED))
1216                 seq_puts(seq, ",degraded");
1217         if (btrfs_test_opt(info, NODATASUM))
1218                 seq_puts(seq, ",nodatasum");
1219         if (btrfs_test_opt(info, NODATACOW))
1220                 seq_puts(seq, ",nodatacow");
1221         if (btrfs_test_opt(info, NOBARRIER))
1222                 seq_puts(seq, ",nobarrier");
1223         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1224                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1225         if (info->thread_pool_size !=  min_t(unsigned long,
1226                                              num_online_cpus() + 2, 8))
1227                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1228         if (btrfs_test_opt(info, COMPRESS)) {
1229                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1230                         compress_type = "zlib";
1231                 else
1232                         compress_type = "lzo";
1233                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1234                         seq_printf(seq, ",compress-force=%s", compress_type);
1235                 else
1236                         seq_printf(seq, ",compress=%s", compress_type);
1237         }
1238         if (btrfs_test_opt(info, NOSSD))
1239                 seq_puts(seq, ",nossd");
1240         if (btrfs_test_opt(info, SSD_SPREAD))
1241                 seq_puts(seq, ",ssd_spread");
1242         else if (btrfs_test_opt(info, SSD))
1243                 seq_puts(seq, ",ssd");
1244         if (btrfs_test_opt(info, NOTREELOG))
1245                 seq_puts(seq, ",notreelog");
1246         if (btrfs_test_opt(info, NOLOGREPLAY))
1247                 seq_puts(seq, ",nologreplay");
1248         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1249                 seq_puts(seq, ",flushoncommit");
1250         if (btrfs_test_opt(info, DISCARD))
1251                 seq_puts(seq, ",discard");
1252         if (!(info->sb->s_flags & MS_POSIXACL))
1253                 seq_puts(seq, ",noacl");
1254         if (btrfs_test_opt(info, SPACE_CACHE))
1255                 seq_puts(seq, ",space_cache");
1256         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1257                 seq_puts(seq, ",space_cache=v2");
1258         else
1259                 seq_puts(seq, ",nospace_cache");
1260         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1261                 seq_puts(seq, ",rescan_uuid_tree");
1262         if (btrfs_test_opt(info, CLEAR_CACHE))
1263                 seq_puts(seq, ",clear_cache");
1264         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1265                 seq_puts(seq, ",user_subvol_rm_allowed");
1266         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1267                 seq_puts(seq, ",enospc_debug");
1268         if (btrfs_test_opt(info, AUTO_DEFRAG))
1269                 seq_puts(seq, ",autodefrag");
1270         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1271                 seq_puts(seq, ",inode_cache");
1272         if (btrfs_test_opt(info, SKIP_BALANCE))
1273                 seq_puts(seq, ",skip_balance");
1274 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1275         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1276                 seq_puts(seq, ",check_int_data");
1277         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1278                 seq_puts(seq, ",check_int");
1279         if (info->check_integrity_print_mask)
1280                 seq_printf(seq, ",check_int_print_mask=%d",
1281                                 info->check_integrity_print_mask);
1282 #endif
1283         if (info->metadata_ratio)
1284                 seq_printf(seq, ",metadata_ratio=%d",
1285                                 info->metadata_ratio);
1286         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1287                 seq_puts(seq, ",fatal_errors=panic");
1288         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1289                 seq_printf(seq, ",commit=%d", info->commit_interval);
1290 #ifdef CONFIG_BTRFS_DEBUG
1291         if (btrfs_test_opt(info, FRAGMENT_DATA))
1292                 seq_puts(seq, ",fragment=data");
1293         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1294                 seq_puts(seq, ",fragment=metadata");
1295 #endif
1296         seq_printf(seq, ",subvolid=%llu",
1297                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1298         seq_puts(seq, ",subvol=");
1299         seq_dentry(seq, dentry, " \t\n\\");
1300         return 0;
1301 }
1302
1303 static int btrfs_test_super(struct super_block *s, void *data)
1304 {
1305         struct btrfs_fs_info *p = data;
1306         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1307
1308         return fs_info->fs_devices == p->fs_devices;
1309 }
1310
1311 static int btrfs_set_super(struct super_block *s, void *data)
1312 {
1313         int err = set_anon_super(s, data);
1314         if (!err)
1315                 s->s_fs_info = data;
1316         return err;
1317 }
1318
1319 /*
1320  * subvolumes are identified by ino 256
1321  */
1322 static inline int is_subvolume_inode(struct inode *inode)
1323 {
1324         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1325                 return 1;
1326         return 0;
1327 }
1328
1329 /*
1330  * This will add subvolid=0 to the argument string while removing any subvol=
1331  * and subvolid= arguments to make sure we get the top-level root for path
1332  * walking to the subvol we want.
1333  */
1334 static char *setup_root_args(char *args)
1335 {
1336         char *buf, *dst, *sep;
1337
1338         if (!args)
1339                 return kstrdup("subvolid=0", GFP_NOFS);
1340
1341         /* The worst case is that we add ",subvolid=0" to the end. */
1342         buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1343         if (!buf)
1344                 return NULL;
1345
1346         while (1) {
1347                 sep = strchrnul(args, ',');
1348                 if (!strstarts(args, "subvol=") &&
1349                     !strstarts(args, "subvolid=")) {
1350                         memcpy(dst, args, sep - args);
1351                         dst += sep - args;
1352                         *dst++ = ',';
1353                 }
1354                 if (*sep)
1355                         args = sep + 1;
1356                 else
1357                         break;
1358         }
1359         strcpy(dst, "subvolid=0");
1360
1361         return buf;
1362 }
1363
1364 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1365                                    int flags, const char *device_name,
1366                                    char *data)
1367 {
1368         struct dentry *root;
1369         struct vfsmount *mnt = NULL;
1370         char *newargs;
1371         int ret;
1372
1373         newargs = setup_root_args(data);
1374         if (!newargs) {
1375                 root = ERR_PTR(-ENOMEM);
1376                 goto out;
1377         }
1378
1379         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1380         if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1381                 if (flags & MS_RDONLY) {
1382                         mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1383                                              device_name, newargs);
1384                 } else {
1385                         mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1386                                              device_name, newargs);
1387                         if (IS_ERR(mnt)) {
1388                                 root = ERR_CAST(mnt);
1389                                 mnt = NULL;
1390                                 goto out;
1391                         }
1392
1393                         down_write(&mnt->mnt_sb->s_umount);
1394                         ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1395                         up_write(&mnt->mnt_sb->s_umount);
1396                         if (ret < 0) {
1397                                 root = ERR_PTR(ret);
1398                                 goto out;
1399                         }
1400                 }
1401         }
1402         if (IS_ERR(mnt)) {
1403                 root = ERR_CAST(mnt);
1404                 mnt = NULL;
1405                 goto out;
1406         }
1407
1408         if (!subvol_name) {
1409                 if (!subvol_objectid) {
1410                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1411                                                           &subvol_objectid);
1412                         if (ret) {
1413                                 root = ERR_PTR(ret);
1414                                 goto out;
1415                         }
1416                 }
1417                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1418                                                             subvol_objectid);
1419                 if (IS_ERR(subvol_name)) {
1420                         root = ERR_CAST(subvol_name);
1421                         subvol_name = NULL;
1422                         goto out;
1423                 }
1424
1425         }
1426
1427         root = mount_subtree(mnt, subvol_name);
1428         /* mount_subtree() drops our reference on the vfsmount. */
1429         mnt = NULL;
1430
1431         if (!IS_ERR(root)) {
1432                 struct super_block *s = root->d_sb;
1433                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1434                 struct inode *root_inode = d_inode(root);
1435                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1436
1437                 ret = 0;
1438                 if (!is_subvolume_inode(root_inode)) {
1439                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1440                                subvol_name);
1441                         ret = -EINVAL;
1442                 }
1443                 if (subvol_objectid && root_objectid != subvol_objectid) {
1444                         /*
1445                          * This will also catch a race condition where a
1446                          * subvolume which was passed by ID is renamed and
1447                          * another subvolume is renamed over the old location.
1448                          */
1449                         btrfs_err(fs_info,
1450                                   "subvol '%s' does not match subvolid %llu",
1451                                   subvol_name, subvol_objectid);
1452                         ret = -EINVAL;
1453                 }
1454                 if (ret) {
1455                         dput(root);
1456                         root = ERR_PTR(ret);
1457                         deactivate_locked_super(s);
1458                 }
1459         }
1460
1461 out:
1462         mntput(mnt);
1463         kfree(newargs);
1464         kfree(subvol_name);
1465         return root;
1466 }
1467
1468 static int parse_security_options(char *orig_opts,
1469                                   struct security_mnt_opts *sec_opts)
1470 {
1471         char *secdata = NULL;
1472         int ret = 0;
1473
1474         secdata = alloc_secdata();
1475         if (!secdata)
1476                 return -ENOMEM;
1477         ret = security_sb_copy_data(orig_opts, secdata);
1478         if (ret) {
1479                 free_secdata(secdata);
1480                 return ret;
1481         }
1482         ret = security_sb_parse_opts_str(secdata, sec_opts);
1483         free_secdata(secdata);
1484         return ret;
1485 }
1486
1487 static int setup_security_options(struct btrfs_fs_info *fs_info,
1488                                   struct super_block *sb,
1489                                   struct security_mnt_opts *sec_opts)
1490 {
1491         int ret = 0;
1492
1493         /*
1494          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1495          * is valid.
1496          */
1497         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1498         if (ret)
1499                 return ret;
1500
1501 #ifdef CONFIG_SECURITY
1502         if (!fs_info->security_opts.num_mnt_opts) {
1503                 /* first time security setup, copy sec_opts to fs_info */
1504                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1505         } else {
1506                 /*
1507                  * Since SELinux (the only one supporting security_mnt_opts)
1508                  * does NOT support changing context during remount/mount of
1509                  * the same sb, this must be the same or part of the same
1510                  * security options, just free it.
1511                  */
1512                 security_free_mnt_opts(sec_opts);
1513         }
1514 #endif
1515         return ret;
1516 }
1517
1518 /*
1519  * Find a superblock for the given device / mount point.
1520  *
1521  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1522  *        for multiple device setup.  Make sure to keep it in sync.
1523  */
1524 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1525                 const char *device_name, void *data)
1526 {
1527         struct block_device *bdev = NULL;
1528         struct super_block *s;
1529         struct btrfs_fs_devices *fs_devices = NULL;
1530         struct btrfs_fs_info *fs_info = NULL;
1531         struct security_mnt_opts new_sec_opts;
1532         fmode_t mode = FMODE_READ;
1533         char *subvol_name = NULL;
1534         u64 subvol_objectid = 0;
1535         int error = 0;
1536
1537         if (!(flags & MS_RDONLY))
1538                 mode |= FMODE_WRITE;
1539
1540         error = btrfs_parse_early_options(data, mode, fs_type,
1541                                           &subvol_name, &subvol_objectid,
1542                                           &fs_devices);
1543         if (error) {
1544                 kfree(subvol_name);
1545                 return ERR_PTR(error);
1546         }
1547
1548         if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1549                 /* mount_subvol() will free subvol_name. */
1550                 return mount_subvol(subvol_name, subvol_objectid, flags,
1551                                     device_name, data);
1552         }
1553
1554         security_init_mnt_opts(&new_sec_opts);
1555         if (data) {
1556                 error = parse_security_options(data, &new_sec_opts);
1557                 if (error)
1558                         return ERR_PTR(error);
1559         }
1560
1561         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1562         if (error)
1563                 goto error_sec_opts;
1564
1565         /*
1566          * Setup a dummy root and fs_info for test/set super.  This is because
1567          * we don't actually fill this stuff out until open_ctree, but we need
1568          * it for searching for existing supers, so this lets us do that and
1569          * then open_ctree will properly initialize everything later.
1570          */
1571         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1572         if (!fs_info) {
1573                 error = -ENOMEM;
1574                 goto error_sec_opts;
1575         }
1576
1577         fs_info->fs_devices = fs_devices;
1578
1579         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1580         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1581         security_init_mnt_opts(&fs_info->security_opts);
1582         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1583                 error = -ENOMEM;
1584                 goto error_fs_info;
1585         }
1586
1587         error = btrfs_open_devices(fs_devices, mode, fs_type);
1588         if (error)
1589                 goto error_fs_info;
1590
1591         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1592                 error = -EACCES;
1593                 goto error_close_devices;
1594         }
1595
1596         bdev = fs_devices->latest_bdev;
1597         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1598                  fs_info);
1599         if (IS_ERR(s)) {
1600                 error = PTR_ERR(s);
1601                 goto error_close_devices;
1602         }
1603
1604         if (s->s_root) {
1605                 btrfs_close_devices(fs_devices);
1606                 free_fs_info(fs_info);
1607                 if ((flags ^ s->s_flags) & MS_RDONLY)
1608                         error = -EBUSY;
1609         } else {
1610                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1611                 btrfs_sb(s)->bdev_holder = fs_type;
1612                 error = btrfs_fill_super(s, fs_devices, data);
1613         }
1614         if (error) {
1615                 deactivate_locked_super(s);
1616                 goto error_sec_opts;
1617         }
1618
1619         fs_info = btrfs_sb(s);
1620         error = setup_security_options(fs_info, s, &new_sec_opts);
1621         if (error) {
1622                 deactivate_locked_super(s);
1623                 goto error_sec_opts;
1624         }
1625
1626         return dget(s->s_root);
1627
1628 error_close_devices:
1629         btrfs_close_devices(fs_devices);
1630 error_fs_info:
1631         free_fs_info(fs_info);
1632 error_sec_opts:
1633         security_free_mnt_opts(&new_sec_opts);
1634         return ERR_PTR(error);
1635 }
1636
1637 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1638                                      int new_pool_size, int old_pool_size)
1639 {
1640         if (new_pool_size == old_pool_size)
1641                 return;
1642
1643         fs_info->thread_pool_size = new_pool_size;
1644
1645         btrfs_info(fs_info, "resize thread pool %d -> %d",
1646                old_pool_size, new_pool_size);
1647
1648         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1649         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1650         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1651         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1652         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1653         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1654         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1655                                 new_pool_size);
1656         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1657         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1658         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1659         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1660         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1661                                 new_pool_size);
1662 }
1663
1664 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1665 {
1666         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1667 }
1668
1669 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1670                                        unsigned long old_opts, int flags)
1671 {
1672         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1673             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1674              (flags & MS_RDONLY))) {
1675                 /* wait for any defraggers to finish */
1676                 wait_event(fs_info->transaction_wait,
1677                            (atomic_read(&fs_info->defrag_running) == 0));
1678                 if (flags & MS_RDONLY)
1679                         sync_filesystem(fs_info->sb);
1680         }
1681 }
1682
1683 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1684                                          unsigned long old_opts)
1685 {
1686         /*
1687          * We need to cleanup all defragable inodes if the autodefragment is
1688          * close or the filesystem is read only.
1689          */
1690         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1691             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1692              (fs_info->sb->s_flags & MS_RDONLY))) {
1693                 btrfs_cleanup_defrag_inodes(fs_info);
1694         }
1695
1696         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1697 }
1698
1699 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1700 {
1701         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1702         struct btrfs_root *root = fs_info->tree_root;
1703         unsigned old_flags = sb->s_flags;
1704         unsigned long old_opts = fs_info->mount_opt;
1705         unsigned long old_compress_type = fs_info->compress_type;
1706         u64 old_max_inline = fs_info->max_inline;
1707         int old_thread_pool_size = fs_info->thread_pool_size;
1708         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1709         int ret;
1710
1711         sync_filesystem(sb);
1712         btrfs_remount_prepare(fs_info);
1713
1714         if (data) {
1715                 struct security_mnt_opts new_sec_opts;
1716
1717                 security_init_mnt_opts(&new_sec_opts);
1718                 ret = parse_security_options(data, &new_sec_opts);
1719                 if (ret)
1720                         goto restore;
1721                 ret = setup_security_options(fs_info, sb,
1722                                              &new_sec_opts);
1723                 if (ret) {
1724                         security_free_mnt_opts(&new_sec_opts);
1725                         goto restore;
1726                 }
1727         }
1728
1729         ret = btrfs_parse_options(fs_info, data, *flags);
1730         if (ret) {
1731                 ret = -EINVAL;
1732                 goto restore;
1733         }
1734
1735         btrfs_remount_begin(fs_info, old_opts, *flags);
1736         btrfs_resize_thread_pool(fs_info,
1737                 fs_info->thread_pool_size, old_thread_pool_size);
1738
1739         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1740                 goto out;
1741
1742         if (*flags & MS_RDONLY) {
1743                 /*
1744                  * this also happens on 'umount -rf' or on shutdown, when
1745                  * the filesystem is busy.
1746                  */
1747                 cancel_work_sync(&fs_info->async_reclaim_work);
1748
1749                 /* wait for the uuid_scan task to finish */
1750                 down(&fs_info->uuid_tree_rescan_sem);
1751                 /* avoid complains from lockdep et al. */
1752                 up(&fs_info->uuid_tree_rescan_sem);
1753
1754                 sb->s_flags |= MS_RDONLY;
1755
1756                 /*
1757                  * Setting MS_RDONLY will put the cleaner thread to
1758                  * sleep at the next loop if it's already active.
1759                  * If it's already asleep, we'll leave unused block
1760                  * groups on disk until we're mounted read-write again
1761                  * unless we clean them up here.
1762                  */
1763                 btrfs_delete_unused_bgs(fs_info);
1764
1765                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1766                 btrfs_scrub_cancel(fs_info);
1767                 btrfs_pause_balance(fs_info);
1768
1769                 ret = btrfs_commit_super(fs_info);
1770                 if (ret)
1771                         goto restore;
1772         } else {
1773                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1774                         btrfs_err(fs_info,
1775                                 "Remounting read-write after error is not allowed");
1776                         ret = -EINVAL;
1777                         goto restore;
1778                 }
1779                 if (fs_info->fs_devices->rw_devices == 0) {
1780                         ret = -EACCES;
1781                         goto restore;
1782                 }
1783
1784                 if (fs_info->fs_devices->missing_devices >
1785                      fs_info->num_tolerated_disk_barrier_failures) {
1786                         btrfs_warn(fs_info,
1787                                 "too many missing devices, writeable remount is not allowed");
1788                         ret = -EACCES;
1789                         goto restore;
1790                 }
1791
1792                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1793                         ret = -EINVAL;
1794                         goto restore;
1795                 }
1796
1797                 ret = btrfs_cleanup_fs_roots(fs_info);
1798                 if (ret)
1799                         goto restore;
1800
1801                 /* recover relocation */
1802                 mutex_lock(&fs_info->cleaner_mutex);
1803                 ret = btrfs_recover_relocation(root);
1804                 mutex_unlock(&fs_info->cleaner_mutex);
1805                 if (ret)
1806                         goto restore;
1807
1808                 ret = btrfs_resume_balance_async(fs_info);
1809                 if (ret)
1810                         goto restore;
1811
1812                 ret = btrfs_resume_dev_replace_async(fs_info);
1813                 if (ret) {
1814                         btrfs_warn(fs_info, "failed to resume dev_replace");
1815                         goto restore;
1816                 }
1817
1818                 if (!fs_info->uuid_root) {
1819                         btrfs_info(fs_info, "creating UUID tree");
1820                         ret = btrfs_create_uuid_tree(fs_info);
1821                         if (ret) {
1822                                 btrfs_warn(fs_info,
1823                                            "failed to create the UUID tree %d",
1824                                            ret);
1825                                 goto restore;
1826                         }
1827                 }
1828                 sb->s_flags &= ~MS_RDONLY;
1829
1830                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1831         }
1832 out:
1833         wake_up_process(fs_info->transaction_kthread);
1834         btrfs_remount_cleanup(fs_info, old_opts);
1835         return 0;
1836
1837 restore:
1838         /* We've hit an error - don't reset MS_RDONLY */
1839         if (sb->s_flags & MS_RDONLY)
1840                 old_flags |= MS_RDONLY;
1841         sb->s_flags = old_flags;
1842         fs_info->mount_opt = old_opts;
1843         fs_info->compress_type = old_compress_type;
1844         fs_info->max_inline = old_max_inline;
1845         btrfs_resize_thread_pool(fs_info,
1846                 old_thread_pool_size, fs_info->thread_pool_size);
1847         fs_info->metadata_ratio = old_metadata_ratio;
1848         btrfs_remount_cleanup(fs_info, old_opts);
1849         return ret;
1850 }
1851
1852 /* Used to sort the devices by max_avail(descending sort) */
1853 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1854                                        const void *dev_info2)
1855 {
1856         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1857             ((struct btrfs_device_info *)dev_info2)->max_avail)
1858                 return -1;
1859         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1860                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1861                 return 1;
1862         else
1863         return 0;
1864 }
1865
1866 /*
1867  * sort the devices by max_avail, in which max free extent size of each device
1868  * is stored.(Descending Sort)
1869  */
1870 static inline void btrfs_descending_sort_devices(
1871                                         struct btrfs_device_info *devices,
1872                                         size_t nr_devices)
1873 {
1874         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1875              btrfs_cmp_device_free_bytes, NULL);
1876 }
1877
1878 /*
1879  * The helper to calc the free space on the devices that can be used to store
1880  * file data.
1881  */
1882 static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1883                                        u64 *free_bytes)
1884 {
1885         struct btrfs_device_info *devices_info;
1886         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1887         struct btrfs_device *device;
1888         u64 skip_space;
1889         u64 type;
1890         u64 avail_space;
1891         u64 min_stripe_size;
1892         int min_stripes = 1, num_stripes = 1;
1893         int i = 0, nr_devices;
1894
1895         /*
1896          * We aren't under the device list lock, so this is racy-ish, but good
1897          * enough for our purposes.
1898          */
1899         nr_devices = fs_info->fs_devices->open_devices;
1900         if (!nr_devices) {
1901                 smp_mb();
1902                 nr_devices = fs_info->fs_devices->open_devices;
1903                 ASSERT(nr_devices);
1904                 if (!nr_devices) {
1905                         *free_bytes = 0;
1906                         return 0;
1907                 }
1908         }
1909
1910         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1911                                GFP_KERNEL);
1912         if (!devices_info)
1913                 return -ENOMEM;
1914
1915         /* calc min stripe number for data space allocation */
1916         type = btrfs_data_alloc_profile(fs_info);
1917         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1918                 min_stripes = 2;
1919                 num_stripes = nr_devices;
1920         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1921                 min_stripes = 2;
1922                 num_stripes = 2;
1923         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1924                 min_stripes = 4;
1925                 num_stripes = 4;
1926         }
1927
1928         if (type & BTRFS_BLOCK_GROUP_DUP)
1929                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1930         else
1931                 min_stripe_size = BTRFS_STRIPE_LEN;
1932
1933         rcu_read_lock();
1934         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1935                 if (!device->in_fs_metadata || !device->bdev ||
1936                     device->is_tgtdev_for_dev_replace)
1937                         continue;
1938
1939                 if (i >= nr_devices)
1940                         break;
1941
1942                 avail_space = device->total_bytes - device->bytes_used;
1943
1944                 /* align with stripe_len */
1945                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1946                 avail_space *= BTRFS_STRIPE_LEN;
1947
1948                 /*
1949                  * In order to avoid overwriting the superblock on the drive,
1950                  * btrfs starts at an offset of at least 1MB when doing chunk
1951                  * allocation.
1952                  */
1953                 skip_space = SZ_1M;
1954
1955                 /*
1956                  * we can use the free space in [0, skip_space - 1], subtract
1957                  * it from the total.
1958                  */
1959                 if (avail_space && avail_space >= skip_space)
1960                         avail_space -= skip_space;
1961                 else
1962                         avail_space = 0;
1963
1964                 if (avail_space < min_stripe_size)
1965                         continue;
1966
1967                 devices_info[i].dev = device;
1968                 devices_info[i].max_avail = avail_space;
1969
1970                 i++;
1971         }
1972         rcu_read_unlock();
1973
1974         nr_devices = i;
1975
1976         btrfs_descending_sort_devices(devices_info, nr_devices);
1977
1978         i = nr_devices - 1;
1979         avail_space = 0;
1980         while (nr_devices >= min_stripes) {
1981                 if (num_stripes > nr_devices)
1982                         num_stripes = nr_devices;
1983
1984                 if (devices_info[i].max_avail >= min_stripe_size) {
1985                         int j;
1986                         u64 alloc_size;
1987
1988                         avail_space += devices_info[i].max_avail * num_stripes;
1989                         alloc_size = devices_info[i].max_avail;
1990                         for (j = i + 1 - num_stripes; j <= i; j++)
1991                                 devices_info[j].max_avail -= alloc_size;
1992                 }
1993                 i--;
1994                 nr_devices--;
1995         }
1996
1997         kfree(devices_info);
1998         *free_bytes = avail_space;
1999         return 0;
2000 }
2001
2002 /*
2003  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2004  *
2005  * If there's a redundant raid level at DATA block groups, use the respective
2006  * multiplier to scale the sizes.
2007  *
2008  * Unused device space usage is based on simulating the chunk allocator
2009  * algorithm that respects the device sizes and order of allocations.  This is
2010  * a close approximation of the actual use but there are other factors that may
2011  * change the result (like a new metadata chunk).
2012  *
2013  * If metadata is exhausted, f_bavail will be 0.
2014  */
2015 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2016 {
2017         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2018         struct btrfs_super_block *disk_super = fs_info->super_copy;
2019         struct list_head *head = &fs_info->space_info;
2020         struct btrfs_space_info *found;
2021         u64 total_used = 0;
2022         u64 total_free_data = 0;
2023         u64 total_free_meta = 0;
2024         int bits = dentry->d_sb->s_blocksize_bits;
2025         __be32 *fsid = (__be32 *)fs_info->fsid;
2026         unsigned factor = 1;
2027         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2028         int ret;
2029         u64 thresh = 0;
2030         int mixed = 0;
2031
2032         rcu_read_lock();
2033         list_for_each_entry_rcu(found, head, list) {
2034                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2035                         int i;
2036
2037                         total_free_data += found->disk_total - found->disk_used;
2038                         total_free_data -=
2039                                 btrfs_account_ro_block_groups_free_space(found);
2040
2041                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2042                                 if (!list_empty(&found->block_groups[i])) {
2043                                         switch (i) {
2044                                         case BTRFS_RAID_DUP:
2045                                         case BTRFS_RAID_RAID1:
2046                                         case BTRFS_RAID_RAID10:
2047                                                 factor = 2;
2048                                         }
2049                                 }
2050                         }
2051                 }
2052
2053                 /*
2054                  * Metadata in mixed block goup profiles are accounted in data
2055                  */
2056                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2057                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2058                                 mixed = 1;
2059                         else
2060                                 total_free_meta += found->disk_total -
2061                                         found->disk_used;
2062                 }
2063
2064                 total_used += found->disk_used;
2065         }
2066
2067         rcu_read_unlock();
2068
2069         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2070         buf->f_blocks >>= bits;
2071         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2072
2073         /* Account global block reserve as used, it's in logical size already */
2074         spin_lock(&block_rsv->lock);
2075         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2076         if (buf->f_bfree >= block_rsv->size >> bits)
2077                 buf->f_bfree -= block_rsv->size >> bits;
2078         else
2079                 buf->f_bfree = 0;
2080         spin_unlock(&block_rsv->lock);
2081
2082         buf->f_bavail = div_u64(total_free_data, factor);
2083         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2084         if (ret)
2085                 return ret;
2086         buf->f_bavail += div_u64(total_free_data, factor);
2087         buf->f_bavail = buf->f_bavail >> bits;
2088
2089         /*
2090          * We calculate the remaining metadata space minus global reserve. If
2091          * this is (supposedly) smaller than zero, there's no space. But this
2092          * does not hold in practice, the exhausted state happens where's still
2093          * some positive delta. So we apply some guesswork and compare the
2094          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2095          *
2096          * We probably cannot calculate the exact threshold value because this
2097          * depends on the internal reservations requested by various
2098          * operations, so some operations that consume a few metadata will
2099          * succeed even if the Avail is zero. But this is better than the other
2100          * way around.
2101          */
2102         thresh = 4 * 1024 * 1024;
2103
2104         if (!mixed && total_free_meta - thresh < block_rsv->size)
2105                 buf->f_bavail = 0;
2106
2107         buf->f_type = BTRFS_SUPER_MAGIC;
2108         buf->f_bsize = dentry->d_sb->s_blocksize;
2109         buf->f_namelen = BTRFS_NAME_LEN;
2110
2111         /* We treat it as constant endianness (it doesn't matter _which_)
2112            because we want the fsid to come out the same whether mounted
2113            on a big-endian or little-endian host */
2114         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2115         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2116         /* Mask in the root object ID too, to disambiguate subvols */
2117         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2118         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2119
2120         return 0;
2121 }
2122
2123 static void btrfs_kill_super(struct super_block *sb)
2124 {
2125         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2126         kill_anon_super(sb);
2127         free_fs_info(fs_info);
2128 }
2129
2130 static struct file_system_type btrfs_fs_type = {
2131         .owner          = THIS_MODULE,
2132         .name           = "btrfs",
2133         .mount          = btrfs_mount,
2134         .kill_sb        = btrfs_kill_super,
2135         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2136 };
2137 MODULE_ALIAS_FS("btrfs");
2138
2139 static int btrfs_control_open(struct inode *inode, struct file *file)
2140 {
2141         /*
2142          * The control file's private_data is used to hold the
2143          * transaction when it is started and is used to keep
2144          * track of whether a transaction is already in progress.
2145          */
2146         file->private_data = NULL;
2147         return 0;
2148 }
2149
2150 /*
2151  * used by btrfsctl to scan devices when no FS is mounted
2152  */
2153 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2154                                 unsigned long arg)
2155 {
2156         struct btrfs_ioctl_vol_args *vol;
2157         struct btrfs_fs_devices *fs_devices;
2158         int ret = -ENOTTY;
2159
2160         if (!capable(CAP_SYS_ADMIN))
2161                 return -EPERM;
2162
2163         vol = memdup_user((void __user *)arg, sizeof(*vol));
2164         if (IS_ERR(vol))
2165                 return PTR_ERR(vol);
2166
2167         switch (cmd) {
2168         case BTRFS_IOC_SCAN_DEV:
2169                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2170                                             &btrfs_fs_type, &fs_devices);
2171                 break;
2172         case BTRFS_IOC_DEVICES_READY:
2173                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2174                                             &btrfs_fs_type, &fs_devices);
2175                 if (ret)
2176                         break;
2177                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2178                 break;
2179         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2180                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2181                 break;
2182         }
2183
2184         kfree(vol);
2185         return ret;
2186 }
2187
2188 static int btrfs_freeze(struct super_block *sb)
2189 {
2190         struct btrfs_trans_handle *trans;
2191         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2192         struct btrfs_root *root = fs_info->tree_root;
2193
2194         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2195         /*
2196          * We don't need a barrier here, we'll wait for any transaction that
2197          * could be in progress on other threads (and do delayed iputs that
2198          * we want to avoid on a frozen filesystem), or do the commit
2199          * ourselves.
2200          */
2201         trans = btrfs_attach_transaction_barrier(root);
2202         if (IS_ERR(trans)) {
2203                 /* no transaction, don't bother */
2204                 if (PTR_ERR(trans) == -ENOENT)
2205                         return 0;
2206                 return PTR_ERR(trans);
2207         }
2208         return btrfs_commit_transaction(trans);
2209 }
2210
2211 static int btrfs_unfreeze(struct super_block *sb)
2212 {
2213         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2214
2215         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2216         return 0;
2217 }
2218
2219 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2220 {
2221         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2222         struct btrfs_fs_devices *cur_devices;
2223         struct btrfs_device *dev, *first_dev = NULL;
2224         struct list_head *head;
2225         struct rcu_string *name;
2226
2227         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2228         cur_devices = fs_info->fs_devices;
2229         while (cur_devices) {
2230                 head = &cur_devices->devices;
2231                 list_for_each_entry(dev, head, dev_list) {
2232                         if (dev->missing)
2233                                 continue;
2234                         if (!dev->name)
2235                                 continue;
2236                         if (!first_dev || dev->devid < first_dev->devid)
2237                                 first_dev = dev;
2238                 }
2239                 cur_devices = cur_devices->seed;
2240         }
2241
2242         if (first_dev) {
2243                 rcu_read_lock();
2244                 name = rcu_dereference(first_dev->name);
2245                 seq_escape(m, name->str, " \t\n\\");
2246                 rcu_read_unlock();
2247         } else {
2248                 WARN_ON(1);
2249         }
2250         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2251         return 0;
2252 }
2253
2254 static const struct super_operations btrfs_super_ops = {
2255         .drop_inode     = btrfs_drop_inode,
2256         .evict_inode    = btrfs_evict_inode,
2257         .put_super      = btrfs_put_super,
2258         .sync_fs        = btrfs_sync_fs,
2259         .show_options   = btrfs_show_options,
2260         .show_devname   = btrfs_show_devname,
2261         .write_inode    = btrfs_write_inode,
2262         .alloc_inode    = btrfs_alloc_inode,
2263         .destroy_inode  = btrfs_destroy_inode,
2264         .statfs         = btrfs_statfs,
2265         .remount_fs     = btrfs_remount,
2266         .freeze_fs      = btrfs_freeze,
2267         .unfreeze_fs    = btrfs_unfreeze,
2268 };
2269
2270 static const struct file_operations btrfs_ctl_fops = {
2271         .open = btrfs_control_open,
2272         .unlocked_ioctl  = btrfs_control_ioctl,
2273         .compat_ioctl = btrfs_control_ioctl,
2274         .owner   = THIS_MODULE,
2275         .llseek = noop_llseek,
2276 };
2277
2278 static struct miscdevice btrfs_misc = {
2279         .minor          = BTRFS_MINOR,
2280         .name           = "btrfs-control",
2281         .fops           = &btrfs_ctl_fops
2282 };
2283
2284 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2285 MODULE_ALIAS("devname:btrfs-control");
2286
2287 static int btrfs_interface_init(void)
2288 {
2289         return misc_register(&btrfs_misc);
2290 }
2291
2292 static void btrfs_interface_exit(void)
2293 {
2294         misc_deregister(&btrfs_misc);
2295 }
2296
2297 static void btrfs_print_mod_info(void)
2298 {
2299         pr_info("Btrfs loaded, crc32c=%s"
2300 #ifdef CONFIG_BTRFS_DEBUG
2301                         ", debug=on"
2302 #endif
2303 #ifdef CONFIG_BTRFS_ASSERT
2304                         ", assert=on"
2305 #endif
2306 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2307                         ", integrity-checker=on"
2308 #endif
2309                         "\n",
2310                         btrfs_crc32c_impl());
2311 }
2312
2313 static int __init init_btrfs_fs(void)
2314 {
2315         int err;
2316
2317         err = btrfs_hash_init();
2318         if (err)
2319                 return err;
2320
2321         btrfs_props_init();
2322
2323         err = btrfs_init_sysfs();
2324         if (err)
2325                 goto free_hash;
2326
2327         btrfs_init_compress();
2328
2329         err = btrfs_init_cachep();
2330         if (err)
2331                 goto free_compress;
2332
2333         err = extent_io_init();
2334         if (err)
2335                 goto free_cachep;
2336
2337         err = extent_map_init();
2338         if (err)
2339                 goto free_extent_io;
2340
2341         err = ordered_data_init();
2342         if (err)
2343                 goto free_extent_map;
2344
2345         err = btrfs_delayed_inode_init();
2346         if (err)
2347                 goto free_ordered_data;
2348
2349         err = btrfs_auto_defrag_init();
2350         if (err)
2351                 goto free_delayed_inode;
2352
2353         err = btrfs_delayed_ref_init();
2354         if (err)
2355                 goto free_auto_defrag;
2356
2357         err = btrfs_prelim_ref_init();
2358         if (err)
2359                 goto free_delayed_ref;
2360
2361         err = btrfs_end_io_wq_init();
2362         if (err)
2363                 goto free_prelim_ref;
2364
2365         err = btrfs_interface_init();
2366         if (err)
2367                 goto free_end_io_wq;
2368
2369         btrfs_init_lockdep();
2370
2371         btrfs_print_mod_info();
2372
2373         err = btrfs_run_sanity_tests();
2374         if (err)
2375                 goto unregister_ioctl;
2376
2377         err = register_filesystem(&btrfs_fs_type);
2378         if (err)
2379                 goto unregister_ioctl;
2380
2381         return 0;
2382
2383 unregister_ioctl:
2384         btrfs_interface_exit();
2385 free_end_io_wq:
2386         btrfs_end_io_wq_exit();
2387 free_prelim_ref:
2388         btrfs_prelim_ref_exit();
2389 free_delayed_ref:
2390         btrfs_delayed_ref_exit();
2391 free_auto_defrag:
2392         btrfs_auto_defrag_exit();
2393 free_delayed_inode:
2394         btrfs_delayed_inode_exit();
2395 free_ordered_data:
2396         ordered_data_exit();
2397 free_extent_map:
2398         extent_map_exit();
2399 free_extent_io:
2400         extent_io_exit();
2401 free_cachep:
2402         btrfs_destroy_cachep();
2403 free_compress:
2404         btrfs_exit_compress();
2405         btrfs_exit_sysfs();
2406 free_hash:
2407         btrfs_hash_exit();
2408         return err;
2409 }
2410
2411 static void __exit exit_btrfs_fs(void)
2412 {
2413         btrfs_destroy_cachep();
2414         btrfs_delayed_ref_exit();
2415         btrfs_auto_defrag_exit();
2416         btrfs_delayed_inode_exit();
2417         btrfs_prelim_ref_exit();
2418         ordered_data_exit();
2419         extent_map_exit();
2420         extent_io_exit();
2421         btrfs_interface_exit();
2422         btrfs_end_io_wq_exit();
2423         unregister_filesystem(&btrfs_fs_type);
2424         btrfs_exit_sysfs();
2425         btrfs_cleanup_fs_uuids();
2426         btrfs_exit_compress();
2427         btrfs_hash_exit();
2428 }
2429
2430 late_initcall(init_btrfs_fs);
2431 module_exit(exit_btrfs_fs)
2432
2433 MODULE_LICENSE("GPL");