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 #include "backref.h"
  65 #define CREATE_TRACE_POINTS
  66 #include <trace/events/btrfs.h>
  67
  68 static const struct super_operations btrfs_super_ops;
  69 static struct file_system_type btrfs_fs_type;
  70
  71 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  72
  73 const char *btrfs_decode_error(int errno)
  74 {
  75         char *errstr = "unknown";
  76
  77         switch (errno) {
  78         case -EIO:
  79                 errstr = "IO failure";
  80                 break;
  81         case -ENOMEM:
  82                 errstr = "Out of memory";
  83                 break;
  84         case -EROFS:
  85                 errstr = "Readonly filesystem";
  86                 break;
  87         case -EEXIST:
  88                 errstr = "Object already exists";
  89                 break;
  90         case -ENOSPC:
  91                 errstr = "No space left";
  92                 break;
  93         case -ENOENT:
  94                 errstr = "No such entry";
  95                 break;
  96         }
  97
  98         return errstr;
  99 }
 100
 101 /* btrfs handle error by forcing the filesystem readonly */
 102 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 103 {
 104         struct super_block *sb = fs_info->sb;
 105
 106         if (sb->s_flags & MS_RDONLY)
 107                 return;
 108
 109         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 110                 sb->s_flags |= MS_RDONLY;
 111                 btrfs_info(fs_info, "forced readonly");
 112                 /*
 113                  * Note that a running device replace operation is not
 114                  * canceled here although there is no way to update
 115                  * the progress. It would add the risk of a deadlock,
 116                  * therefore the canceling is omitted. The only penalty
 117                  * is that some I/O remains active until the procedure
 118                  * completes. The next time when the filesystem is
 119                  * mounted writeable again, the device replace
 120                  * operation continues.
 121                  */
 122         }
 123 }
 124
 125 /*
 126  * __btrfs_handle_fs_error decodes expected errors from the caller and
 127  * invokes the approciate error response.
 128  */
 129 __cold
 130 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
 131                        unsigned int line, int errno, const char *fmt, ...)
 132 {
 133         struct super_block *sb = fs_info->sb;
 134 #ifdef CONFIG_PRINTK
 135         const char *errstr;
 136 #endif
 137
 138         /*
 139          * Special case: if the error is EROFS, and we're already
 140          * under MS_RDONLY, then it is safe here.
 141          */
 142         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 143                 return;
 144
 145 #ifdef CONFIG_PRINTK
 146         errstr = btrfs_decode_error(errno);
 147         if (fmt) {
 148                 struct va_format vaf;
 149                 va_list args;
 150
 151                 va_start(args, fmt);
 152                 vaf.fmt = fmt;
 153                 vaf.va = &args;
 154
 155                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 156                         sb->s_id, function, line, errno, errstr, &vaf);
 157                 va_end(args);
 158         } else {
 159                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 160                         sb->s_id, function, line, errno, errstr);
 161         }
 162 #endif
 163
 164         /*
 165          * Today we only save the error info to memory.  Long term we'll
 166          * also send it down to the disk
 167          */
 168         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 169
 170         /* Don't go through full error handling during mount */
 171         if (sb->s_flags & MS_BORN)
 172                 btrfs_handle_error(fs_info);
 173 }
 174
 175 #ifdef CONFIG_PRINTK
 176 static const char * const logtypes[] = {
 177         "emergency",
 178         "alert",
 179         "critical",
 180         "error",
 181         "warning",
 182         "notice",
 183         "info",
 184         "debug",
 185 };
 186
 187
 188 /*
 189  * Use one ratelimit state per log level so that a flood of less important
 190  * messages doesn't cause more important ones to be dropped.
 191  */
 192 static struct ratelimit_state printk_limits[] = {
 193         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
 194         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
 195         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
 196         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
 197         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
 198         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
 199         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
 200         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
 201 };
 202
 203 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 204 {
 205         struct super_block *sb = fs_info->sb;
 206         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
 207         struct va_format vaf;
 208         va_list args;
 209         int kern_level;
 210         const char *type = logtypes[4];
 211         struct ratelimit_state *ratelimit = &printk_limits[4];
 212
 213         va_start(args, fmt);
 214
 215         while ((kern_level = printk_get_level(fmt)) != 0) {
 216                 size_t size = printk_skip_level(fmt) - fmt;
 217
 218                 if (kern_level >= '0' && kern_level <= '7') {
 219                         memcpy(lvl, fmt,  size);
 220                         lvl[size] = '\0';
 221                         type = logtypes[kern_level - '0'];
 222                         ratelimit = &printk_limits[kern_level - '0'];
 223                 }
 224                 fmt += size;
 225         }
 226
 227         vaf.fmt = fmt;
 228         vaf.va = &args;
 229
 230         if (__ratelimit(ratelimit))
 231                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
 232
 233         va_end(args);
 234 }
 235 #endif
 236
 237 /*
 238  * We only mark the transaction aborted and then set the file system read-only.
 239  * This will prevent new transactions from starting or trying to join this
 240  * one.
 241  *
 242  * This means that error recovery at the call site is limited to freeing
 243  * any local memory allocations and passing the error code up without
 244  * further cleanup. The transaction should complete as it normally would
 245  * in the call path but will return -EIO.
 246  *
 247  * We'll complete the cleanup in btrfs_end_transaction and
 248  * btrfs_commit_transaction.
 249  */
 250 __cold
 251 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 252                                const char *function,
 253                                unsigned int line, int errno)
 254 {
 255         struct btrfs_fs_info *fs_info = trans->fs_info;
 256
 257         trans->aborted = errno;
 258         /* Nothing used. The other threads that have joined this
 259          * transaction may be able to continue. */
 260         if (!trans->dirty && list_empty(&trans->new_bgs)) {
 261                 const char *errstr;
 262
 263                 errstr = btrfs_decode_error(errno);
 264                 btrfs_warn(fs_info,
 265                            "%s:%d: Aborting unused transaction(%s).",
 266                            function, line, errstr);
 267                 return;
 268         }
 269         WRITE_ONCE(trans->transaction->aborted, errno);
 270         /* Wake up anybody who may be waiting on this transaction */
 271         wake_up(&fs_info->transaction_wait);
 272         wake_up(&fs_info->transaction_blocked_wait);
 273         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
 274 }
 275 /*
 276  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 277  * issues an alert, and either panics or BUGs, depending on mount options.
 278  */
 279 __cold
 280 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 281                    unsigned int line, int errno, const char *fmt, ...)
 282 {
 283         char *s_id = "<unknown>";
 284         const char *errstr;
 285         struct va_format vaf = { .fmt = fmt };
 286         va_list args;
 287
 288         if (fs_info)
 289                 s_id = fs_info->sb->s_id;
 290
 291         va_start(args, fmt);
 292         vaf.va = &args;
 293
 294         errstr = btrfs_decode_error(errno);
 295         if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
 296                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 297                         s_id, function, line, &vaf, errno, errstr);
 298
 299         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 300                    function, line, &vaf, errno, errstr);
 301         va_end(args);
 302         /* Caller calls BUG() */
 303 }
 304
 305 static void btrfs_put_super(struct super_block *sb)
 306 {
 307         close_ctree(btrfs_sb(sb));
 308 }
 309
 310 enum {
 311         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 312         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 313         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 314         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 315         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 316         Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 317         Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 318         Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 319         Opt_skip_balance, Opt_check_integrity,
 320         Opt_check_integrity_including_extent_data,
 321         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 322         Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
 323         Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
 324         Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
 325         Opt_nologreplay, Opt_norecovery,
 326 #ifdef CONFIG_BTRFS_DEBUG
 327         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 328 #endif
 329         Opt_err,
 330 };
 331
 332 static const match_table_t tokens = {
 333         {Opt_degraded, "degraded"},
 334         {Opt_subvol, "subvol=%s"},
 335         {Opt_subvolid, "subvolid=%s"},
 336         {Opt_device, "device=%s"},
 337         {Opt_nodatasum, "nodatasum"},
 338         {Opt_datasum, "datasum"},
 339         {Opt_nodatacow, "nodatacow"},
 340         {Opt_datacow, "datacow"},
 341         {Opt_nobarrier, "nobarrier"},
 342         {Opt_barrier, "barrier"},
 343         {Opt_max_inline, "max_inline=%s"},
 344         {Opt_alloc_start, "alloc_start=%s"},
 345         {Opt_thread_pool, "thread_pool=%d"},
 346         {Opt_compress, "compress"},
 347         {Opt_compress_type, "compress=%s"},
 348         {Opt_compress_force, "compress-force"},
 349         {Opt_compress_force_type, "compress-force=%s"},
 350         {Opt_ssd, "ssd"},
 351         {Opt_ssd_spread, "ssd_spread"},
 352         {Opt_nossd, "nossd"},
 353         {Opt_acl, "acl"},
 354         {Opt_noacl, "noacl"},
 355         {Opt_notreelog, "notreelog"},
 356         {Opt_treelog, "treelog"},
 357         {Opt_nologreplay, "nologreplay"},
 358         {Opt_norecovery, "norecovery"},
 359         {Opt_flushoncommit, "flushoncommit"},
 360         {Opt_noflushoncommit, "noflushoncommit"},
 361         {Opt_ratio, "metadata_ratio=%d"},
 362         {Opt_discard, "discard"},
 363         {Opt_nodiscard, "nodiscard"},
 364         {Opt_space_cache, "space_cache"},
 365         {Opt_space_cache_version, "space_cache=%s"},
 366         {Opt_clear_cache, "clear_cache"},
 367         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 368         {Opt_enospc_debug, "enospc_debug"},
 369         {Opt_noenospc_debug, "noenospc_debug"},
 370         {Opt_subvolrootid, "subvolrootid=%d"},
 371         {Opt_defrag, "autodefrag"},
 372         {Opt_nodefrag, "noautodefrag"},
 373         {Opt_inode_cache, "inode_cache"},
 374         {Opt_noinode_cache, "noinode_cache"},
 375         {Opt_no_space_cache, "nospace_cache"},
 376         {Opt_recovery, "recovery"}, /* deprecated */
 377         {Opt_usebackuproot, "usebackuproot"},
 378         {Opt_skip_balance, "skip_balance"},
 379         {Opt_check_integrity, "check_int"},
 380         {Opt_check_integrity_including_extent_data, "check_int_data"},
 381         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 382         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 383         {Opt_fatal_errors, "fatal_errors=%s"},
 384         {Opt_commit_interval, "commit=%d"},
 385 #ifdef CONFIG_BTRFS_DEBUG
 386         {Opt_fragment_data, "fragment=data"},
 387         {Opt_fragment_metadata, "fragment=metadata"},
 388         {Opt_fragment_all, "fragment=all"},
 389 #endif
 390         {Opt_err, NULL},
 391 };
 392
 393 /*
 394  * Regular mount options parser.  Everything that is needed only when
 395  * reading in a new superblock is parsed here.
 396  * XXX JDM: This needs to be cleaned up for remount.
 397  */
 398 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 399                         unsigned long new_flags)
 400 {
 401         substring_t args[MAX_OPT_ARGS];
 402         char *p, *num, *orig = NULL;
 403         u64 cache_gen;
 404         int intarg;
 405         int ret = 0;
 406         char *compress_type;
 407         bool compress_force = false;
 408         enum btrfs_compression_type saved_compress_type;
 409         bool saved_compress_force;
 410         int no_compress = 0;
 411
 412         cache_gen = btrfs_super_cache_generation(info->super_copy);
 413         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 414                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 415         else if (cache_gen)
 416                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 417
 418         /*
 419          * Even the options are empty, we still need to do extra check
 420          * against new flags
 421          */
 422         if (!options)
 423                 goto check;
 424
 425         /*
 426          * strsep changes the string, duplicate it because parse_options
 427          * gets called twice
 428          */
 429         options = kstrdup(options, GFP_KERNEL);
 430         if (!options)
 431                 return -ENOMEM;
 432
 433         orig = options;
 434
 435         while ((p = strsep(&options, ",")) != NULL) {
 436                 int token;
 437                 if (!*p)
 438                         continue;
 439
 440                 token = match_token(p, tokens, args);
 441                 switch (token) {
 442                 case Opt_degraded:
 443                         btrfs_info(info, "allowing degraded mounts");
 444                         btrfs_set_opt(info->mount_opt, DEGRADED);
 445                         break;
 446                 case Opt_subvol:
 447                 case Opt_subvolid:
 448                 case Opt_subvolrootid:
 449                 case Opt_device:
 450                         /*
 451                          * These are parsed by btrfs_parse_early_options
 452                          * and can be happily ignored here.
 453                          */
 454                         break;
 455                 case Opt_nodatasum:
 456                         btrfs_set_and_info(info, NODATASUM,
 457                                            "setting nodatasum");
 458                         break;
 459                 case Opt_datasum:
 460                         if (btrfs_test_opt(info, NODATASUM)) {
 461                                 if (btrfs_test_opt(info, NODATACOW))
 462                                         btrfs_info(info,
 463                                                    "setting datasum, datacow enabled");
 464                                 else
 465                                         btrfs_info(info, "setting datasum");
 466                         }
 467                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 468                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 469                         break;
 470                 case Opt_nodatacow:
 471                         if (!btrfs_test_opt(info, NODATACOW)) {
 472                                 if (!btrfs_test_opt(info, COMPRESS) ||
 473                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
 474                                         btrfs_info(info,
 475                                                    "setting nodatacow, compression disabled");
 476                                 } else {
 477                                         btrfs_info(info, "setting nodatacow");
 478                                 }
 479                         }
 480                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 481                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 482                         btrfs_set_opt(info->mount_opt, NODATACOW);
 483                         btrfs_set_opt(info->mount_opt, NODATASUM);
 484                         break;
 485                 case Opt_datacow:
 486                         btrfs_clear_and_info(info, NODATACOW,
 487                                              "setting datacow");
 488                         break;
 489                 case Opt_compress_force:
 490                 case Opt_compress_force_type:
 491                         compress_force = true;
 492                         /* Fallthrough */
 493                 case Opt_compress:
 494                 case Opt_compress_type:
 495                         saved_compress_type = btrfs_test_opt(info,
 496                                                              COMPRESS) ?
 497                                 info->compress_type : BTRFS_COMPRESS_NONE;
 498                         saved_compress_force =
 499                                 btrfs_test_opt(info, FORCE_COMPRESS);
 500                         if (token == Opt_compress ||
 501                             token == Opt_compress_force ||
 502                             strncmp(args[0].from, "zlib", 4) == 0) {
 503                                 compress_type = "zlib";
 504                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 505                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 506                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 507                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 508                                 no_compress = 0;
 509                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
 510                                 compress_type = "lzo";
 511                                 info->compress_type = BTRFS_COMPRESS_LZO;
 512                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 513                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 514                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 515                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 516                                 no_compress = 0;
 517                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 518                                 compress_type = "no";
 519                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 520                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 521                                 compress_force = false;
 522                                 no_compress++;
 523                         } else {
 524                                 ret = -EINVAL;
 525                                 goto out;
 526                         }
 527
 528                         if (compress_force) {
 529                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 530                         } else {
 531                                 /*
 532                                  * If we remount from compress-force=xxx to
 533                                  * compress=xxx, we need clear FORCE_COMPRESS
 534                                  * flag, otherwise, there is no way for users
 535                                  * to disable forcible compression separately.
 536                                  */
 537                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 538                         }
 539                         if ((btrfs_test_opt(info, COMPRESS) &&
 540                              (info->compress_type != saved_compress_type ||
 541                               compress_force != saved_compress_force)) ||
 542                             (!btrfs_test_opt(info, COMPRESS) &&
 543                              no_compress == 1)) {
 544                                 btrfs_info(info, "%s %s compression",
 545                                            (compress_force) ? "force" : "use",
 546                                            compress_type);
 547                         }
 548                         compress_force = false;
 549                         break;
 550                 case Opt_ssd:
 551                         btrfs_set_and_info(info, SSD,
 552                                            "enabling ssd optimizations");
 553                         btrfs_clear_opt(info->mount_opt, NOSSD);
 554                         break;
 555                 case Opt_ssd_spread:
 556                         btrfs_set_and_info(info, SSD,
 557                                            "enabling ssd optimizations");
 558                         btrfs_set_and_info(info, SSD_SPREAD,
 559                                            "using spread ssd allocation scheme");
 560                         btrfs_clear_opt(info->mount_opt, NOSSD);
 561                         break;
 562                 case Opt_nossd:
 563                         btrfs_set_opt(info->mount_opt, NOSSD);
 564                         btrfs_clear_and_info(info, SSD,
 565                                              "not using ssd optimizations");
 566                         btrfs_clear_and_info(info, SSD_SPREAD,
 567                                              "not using spread ssd allocation scheme");
 568                         break;
 569                 case Opt_barrier:
 570                         btrfs_clear_and_info(info, NOBARRIER,
 571                                              "turning on barriers");
 572                         break;
 573                 case Opt_nobarrier:
 574                         btrfs_set_and_info(info, NOBARRIER,
 575                                            "turning off barriers");
 576                         break;
 577                 case Opt_thread_pool:
 578                         ret = match_int(&args[0], &intarg);
 579                         if (ret) {
 580                                 goto out;
 581                         } else if (intarg > 0) {
 582                                 info->thread_pool_size = intarg;
 583                         } else {
 584                                 ret = -EINVAL;
 585                                 goto out;
 586                         }
 587                         break;
 588                 case Opt_max_inline:
 589                         num = match_strdup(&args[0]);
 590                         if (num) {
 591                                 info->max_inline = memparse(num, NULL);
 592                                 kfree(num);
 593
 594                                 if (info->max_inline) {
 595                                         info->max_inline = min_t(u64,
 596                                                 info->max_inline,
 597                                                 info->sectorsize);
 598                                 }
 599                                 btrfs_info(info, "max_inline at %llu",
 600                                            info->max_inline);
 601                         } else {
 602                                 ret = -ENOMEM;
 603                                 goto out;
 604                         }
 605                         break;
 606                 case Opt_alloc_start:
 607                         btrfs_info(info,
 608                                 "option alloc_start is obsolete, ignored");
 609                         break;
 610                 case Opt_acl:
 611 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 612                         info->sb->s_flags |= MS_POSIXACL;
 613                         break;
 614 #else
 615                         btrfs_err(info, "support for ACL not compiled in!");
 616                         ret = -EINVAL;
 617                         goto out;
 618 #endif
 619                 case Opt_noacl:
 620                         info->sb->s_flags &= ~MS_POSIXACL;
 621                         break;
 622                 case Opt_notreelog:
 623                         btrfs_set_and_info(info, NOTREELOG,
 624                                            "disabling tree log");
 625                         break;
 626                 case Opt_treelog:
 627                         btrfs_clear_and_info(info, NOTREELOG,
 628                                              "enabling tree log");
 629                         break;
 630                 case Opt_norecovery:
 631                 case Opt_nologreplay:
 632                         btrfs_set_and_info(info, NOLOGREPLAY,
 633                                            "disabling log replay at mount time");
 634                         break;
 635                 case Opt_flushoncommit:
 636                         btrfs_set_and_info(info, FLUSHONCOMMIT,
 637                                            "turning on flush-on-commit");
 638                         break;
 639                 case Opt_noflushoncommit:
 640                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
 641                                              "turning off flush-on-commit");
 642                         break;
 643                 case Opt_ratio:
 644                         ret = match_int(&args[0], &intarg);
 645                         if (ret) {
 646                                 goto out;
 647                         } else if (intarg >= 0) {
 648                                 info->metadata_ratio = intarg;
 649                                 btrfs_info(info, "metadata ratio %d",
 650                                            info->metadata_ratio);
 651                         } else {
 652                                 ret = -EINVAL;
 653                                 goto out;
 654                         }
 655                         break;
 656                 case Opt_discard:
 657                         btrfs_set_and_info(info, DISCARD,
 658                                            "turning on discard");
 659                         break;
 660                 case Opt_nodiscard:
 661                         btrfs_clear_and_info(info, DISCARD,
 662                                              "turning off discard");
 663                         break;
 664                 case Opt_space_cache:
 665                 case Opt_space_cache_version:
 666                         if (token == Opt_space_cache ||
 667                             strcmp(args[0].from, "v1") == 0) {
 668                                 btrfs_clear_opt(info->mount_opt,
 669                                                 FREE_SPACE_TREE);
 670                                 btrfs_set_and_info(info, SPACE_CACHE,
 671                                            "enabling disk space caching");
 672                         } else if (strcmp(args[0].from, "v2") == 0) {
 673                                 btrfs_clear_opt(info->mount_opt,
 674                                                 SPACE_CACHE);
 675                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
 676                                                    "enabling free space tree");
 677                         } else {
 678                                 ret = -EINVAL;
 679                                 goto out;
 680                         }
 681                         break;
 682                 case Opt_rescan_uuid_tree:
 683                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 684                         break;
 685                 case Opt_no_space_cache:
 686                         if (btrfs_test_opt(info, SPACE_CACHE)) {
 687                                 btrfs_clear_and_info(info, SPACE_CACHE,
 688                                              "disabling disk space caching");
 689                         }
 690                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
 691                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
 692                                              "disabling free space tree");
 693                         }
 694                         break;
 695                 case Opt_inode_cache:
 696                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 697                                            "enabling inode map caching");
 698                         break;
 699                 case Opt_noinode_cache:
 700                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 701                                              "disabling inode map caching");
 702                         break;
 703                 case Opt_clear_cache:
 704                         btrfs_set_and_info(info, CLEAR_CACHE,
 705                                            "force clearing of disk cache");
 706                         break;
 707                 case Opt_user_subvol_rm_allowed:
 708                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 709                         break;
 710                 case Opt_enospc_debug:
 711                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 712                         break;
 713                 case Opt_noenospc_debug:
 714                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 715                         break;
 716                 case Opt_defrag:
 717                         btrfs_set_and_info(info, AUTO_DEFRAG,
 718                                            "enabling auto defrag");
 719                         break;
 720                 case Opt_nodefrag:
 721                         btrfs_clear_and_info(info, AUTO_DEFRAG,
 722                                              "disabling auto defrag");
 723                         break;
 724                 case Opt_recovery:
 725                         btrfs_warn(info,
 726                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 727                 case Opt_usebackuproot:
 728                         btrfs_info(info,
 729                                    "trying to use backup root at mount time");
 730                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 731                         break;
 732                 case Opt_skip_balance:
 733                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 734                         break;
 735 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 736                 case Opt_check_integrity_including_extent_data:
 737                         btrfs_info(info,
 738                                    "enabling check integrity including extent data");
 739                         btrfs_set_opt(info->mount_opt,
 740                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 741                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 742                         break;
 743                 case Opt_check_integrity:
 744                         btrfs_info(info, "enabling check integrity");
 745                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 746                         break;
 747                 case Opt_check_integrity_print_mask:
 748                         ret = match_int(&args[0], &intarg);
 749                         if (ret) {
 750                                 goto out;
 751                         } else if (intarg >= 0) {
 752                                 info->check_integrity_print_mask = intarg;
 753                                 btrfs_info(info,
 754                                            "check_integrity_print_mask 0x%x",
 755                                            info->check_integrity_print_mask);
 756                         } else {
 757                                 ret = -EINVAL;
 758                                 goto out;
 759                         }
 760                         break;
 761 #else
 762                 case Opt_check_integrity_including_extent_data:
 763                 case Opt_check_integrity:
 764                 case Opt_check_integrity_print_mask:
 765                         btrfs_err(info,
 766                                   "support for check_integrity* not compiled in!");
 767                         ret = -EINVAL;
 768                         goto out;
 769 #endif
 770                 case Opt_fatal_errors:
 771                         if (strcmp(args[0].from, "panic") == 0)
 772                                 btrfs_set_opt(info->mount_opt,
 773                                               PANIC_ON_FATAL_ERROR);
 774                         else if (strcmp(args[0].from, "bug") == 0)
 775                                 btrfs_clear_opt(info->mount_opt,
 776                                               PANIC_ON_FATAL_ERROR);
 777                         else {
 778                                 ret = -EINVAL;
 779                                 goto out;
 780                         }
 781                         break;
 782                 case Opt_commit_interval:
 783                         intarg = 0;
 784                         ret = match_int(&args[0], &intarg);
 785                         if (ret < 0) {
 786                                 btrfs_err(info, "invalid commit interval");
 787                                 ret = -EINVAL;
 788                                 goto out;
 789                         }
 790                         if (intarg > 0) {
 791                                 if (intarg > 300) {
 792                                         btrfs_warn(info,
 793                                                 "excessive commit interval %d",
 794                                                 intarg);
 795                                 }
 796                                 info->commit_interval = intarg;
 797                         } else {
 798                                 btrfs_info(info,
 799                                            "using default commit interval %ds",
 800                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
 801                                 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 802                         }
 803                         break;
 804 #ifdef CONFIG_BTRFS_DEBUG
 805                 case Opt_fragment_all:
 806                         btrfs_info(info, "fragmenting all space");
 807                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 808                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 809                         break;
 810                 case Opt_fragment_metadata:
 811                         btrfs_info(info, "fragmenting metadata");
 812                         btrfs_set_opt(info->mount_opt,
 813                                       FRAGMENT_METADATA);
 814                         break;
 815                 case Opt_fragment_data:
 816                         btrfs_info(info, "fragmenting data");
 817                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 818                         break;
 819 #endif
 820                 case Opt_err:
 821                         btrfs_info(info, "unrecognized mount option '%s'", p);
 822                         ret = -EINVAL;
 823                         goto out;
 824                 default:
 825                         break;
 826                 }
 827         }
 828 check:
 829         /*
 830          * Extra check for current option against current flag
 831          */
 832         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
 833                 btrfs_err(info,
 834                           "nologreplay must be used with ro mount option");
 835                 ret = -EINVAL;
 836         }
 837 out:
 838         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
 839             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
 840             !btrfs_test_opt(info, CLEAR_CACHE)) {
 841                 btrfs_err(info, "cannot disable free space tree");
 842                 ret = -EINVAL;
 843
 844         }
 845         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 846                 btrfs_info(info, "disk space caching is enabled");
 847         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
 848                 btrfs_info(info, "using free space tree");
 849         kfree(orig);
 850         return ret;
 851 }
 852
 853 /*
 854  * Parse mount options that are required early in the mount process.
 855  *
 856  * All other options will be parsed on much later in the mount process and
 857  * only when we need to allocate a new super block.
 858  */
 859 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 860                 void *holder, char **subvol_name, u64 *subvol_objectid,
 861                 struct btrfs_fs_devices **fs_devices)
 862 {
 863         substring_t args[MAX_OPT_ARGS];
 864         char *device_name, *opts, *orig, *p;
 865         char *num = NULL;
 866         int error = 0;
 867
 868         if (!options)
 869                 return 0;
 870
 871         /*
 872          * strsep changes the string, duplicate it because parse_options
 873          * gets called twice
 874          */
 875         opts = kstrdup(options, GFP_KERNEL);
 876         if (!opts)
 877                 return -ENOMEM;
 878         orig = opts;
 879
 880         while ((p = strsep(&opts, ",")) != NULL) {
 881                 int token;
 882                 if (!*p)
 883                         continue;
 884
 885                 token = match_token(p, tokens, args);
 886                 switch (token) {
 887                 case Opt_subvol:
 888                         kfree(*subvol_name);
 889                         *subvol_name = match_strdup(&args[0]);
 890                         if (!*subvol_name) {
 891                                 error = -ENOMEM;
 892                                 goto out;
 893                         }
 894                         break;
 895                 case Opt_subvolid:
 896                         num = match_strdup(&args[0]);
 897                         if (num) {
 898                                 *subvol_objectid = memparse(num, NULL);
 899                                 kfree(num);
 900                                 /* we want the original fs_tree */
 901                                 if (!*subvol_objectid)
 902                                         *subvol_objectid =
 903                                                 BTRFS_FS_TREE_OBJECTID;
 904                         } else {
 905                                 error = -EINVAL;
 906                                 goto out;
 907                         }
 908                         break;
 909                 case Opt_subvolrootid:
 910                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
 911                         break;
 912                 case Opt_device:
 913                         device_name = match_strdup(&args[0]);
 914                         if (!device_name) {
 915                                 error = -ENOMEM;
 916                                 goto out;
 917                         }
 918                         error = btrfs_scan_one_device(device_name,
 919                                         flags, holder, fs_devices);
 920                         kfree(device_name);
 921                         if (error)
 922                                 goto out;
 923                         break;
 924                 default:
 925                         break;
 926                 }
 927         }
 928
 929 out:
 930         kfree(orig);
 931         return error;
 932 }
 933
 934 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 935                                            u64 subvol_objectid)
 936 {
 937         struct btrfs_root *root = fs_info->tree_root;
 938         struct btrfs_root *fs_root;
 939         struct btrfs_root_ref *root_ref;
 940         struct btrfs_inode_ref *inode_ref;
 941         struct btrfs_key key;
 942         struct btrfs_path *path = NULL;
 943         char *name = NULL, *ptr;
 944         u64 dirid;
 945         int len;
 946         int ret;
 947
 948         path = btrfs_alloc_path();
 949         if (!path) {
 950                 ret = -ENOMEM;
 951                 goto err;
 952         }
 953         path->leave_spinning = 1;
 954
 955         name = kmalloc(PATH_MAX, GFP_KERNEL);
 956         if (!name) {
 957                 ret = -ENOMEM;
 958                 goto err;
 959         }
 960         ptr = name + PATH_MAX - 1;
 961         ptr[0] = '\0';
 962
 963         /*
 964          * Walk up the subvolume trees in the tree of tree roots by root
 965          * backrefs until we hit the top-level subvolume.
 966          */
 967         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 968                 key.objectid = subvol_objectid;
 969                 key.type = BTRFS_ROOT_BACKREF_KEY;
 970                 key.offset = (u64)-1;
 971
 972                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 973                 if (ret < 0) {
 974                         goto err;
 975                 } else if (ret > 0) {
 976                         ret = btrfs_previous_item(root, path, subvol_objectid,
 977                                                   BTRFS_ROOT_BACKREF_KEY);
 978                         if (ret < 0) {
 979                                 goto err;
 980                         } else if (ret > 0) {
 981                                 ret = -ENOENT;
 982                                 goto err;
 983                         }
 984                 }
 985
 986                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 987                 subvol_objectid = key.offset;
 988
 989                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 990                                           struct btrfs_root_ref);
 991                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
 992                 ptr -= len + 1;
 993                 if (ptr < name) {
 994                         ret = -ENAMETOOLONG;
 995                         goto err;
 996                 }
 997                 read_extent_buffer(path->nodes[0], ptr + 1,
 998                                    (unsigned long)(root_ref + 1), len);
 999                 ptr[0] = '/';
1000                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1001                 btrfs_release_path(path);
1002
1003                 key.objectid = subvol_objectid;
1004                 key.type = BTRFS_ROOT_ITEM_KEY;
1005                 key.offset = (u64)-1;
1006                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1007                 if (IS_ERR(fs_root)) {
1008                         ret = PTR_ERR(fs_root);
1009                         goto err;
1010                 }
1011
1012                 /*
1013                  * Walk up the filesystem tree by inode refs until we hit the
1014                  * root directory.
1015                  */
1016                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1017                         key.objectid = dirid;
1018                         key.type = BTRFS_INODE_REF_KEY;
1019                         key.offset = (u64)-1;
1020
1021                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1022                         if (ret < 0) {
1023                                 goto err;
1024                         } else if (ret > 0) {
1025                                 ret = btrfs_previous_item(fs_root, path, dirid,
1026                                                           BTRFS_INODE_REF_KEY);
1027                                 if (ret < 0) {
1028                                         goto err;
1029                                 } else if (ret > 0) {
1030                                         ret = -ENOENT;
1031                                         goto err;
1032                                 }
1033                         }
1034
1035                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1036                         dirid = key.offset;
1037
1038                         inode_ref = btrfs_item_ptr(path->nodes[0],
1039                                                    path->slots[0],
1040                                                    struct btrfs_inode_ref);
1041                         len = btrfs_inode_ref_name_len(path->nodes[0],
1042                                                        inode_ref);
1043                         ptr -= len + 1;
1044                         if (ptr < name) {
1045                                 ret = -ENAMETOOLONG;
1046                                 goto err;
1047                         }
1048                         read_extent_buffer(path->nodes[0], ptr + 1,
1049                                            (unsigned long)(inode_ref + 1), len);
1050                         ptr[0] = '/';
1051                         btrfs_release_path(path);
1052                 }
1053         }
1054
1055         btrfs_free_path(path);
1056         if (ptr == name + PATH_MAX - 1) {
1057                 name[0] = '/';
1058                 name[1] = '\0';
1059         } else {
1060                 memmove(name, ptr, name + PATH_MAX - ptr);
1061         }
1062         return name;
1063
1064 err:
1065         btrfs_free_path(path);
1066         kfree(name);
1067         return ERR_PTR(ret);
1068 }
1069
1070 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1071 {
1072         struct btrfs_root *root = fs_info->tree_root;
1073         struct btrfs_dir_item *di;
1074         struct btrfs_path *path;
1075         struct btrfs_key location;
1076         u64 dir_id;
1077
1078         path = btrfs_alloc_path();
1079         if (!path)
1080                 return -ENOMEM;
1081         path->leave_spinning = 1;
1082
1083         /*
1084          * Find the "default" dir item which points to the root item that we
1085          * will mount by default if we haven't been given a specific subvolume
1086          * to mount.
1087          */
1088         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1089         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1090         if (IS_ERR(di)) {
1091                 btrfs_free_path(path);
1092                 return PTR_ERR(di);
1093         }
1094         if (!di) {
1095                 /*
1096                  * Ok the default dir item isn't there.  This is weird since
1097                  * it's always been there, but don't freak out, just try and
1098                  * mount the top-level subvolume.
1099                  */
1100                 btrfs_free_path(path);
1101                 *objectid = BTRFS_FS_TREE_OBJECTID;
1102                 return 0;
1103         }
1104
1105         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1106         btrfs_free_path(path);
1107         *objectid = location.objectid;
1108         return 0;
1109 }
1110
1111 static int btrfs_fill_super(struct super_block *sb,
1112                             struct btrfs_fs_devices *fs_devices,
1113                             void *data)
1114 {
1115         struct inode *inode;
1116         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1117         struct btrfs_key key;
1118         int err;
1119
1120         sb->s_maxbytes = MAX_LFS_FILESIZE;
1121         sb->s_magic = BTRFS_SUPER_MAGIC;
1122         sb->s_op = &btrfs_super_ops;
1123         sb->s_d_op = &btrfs_dentry_operations;
1124         sb->s_export_op = &btrfs_export_ops;
1125         sb->s_xattr = btrfs_xattr_handlers;
1126         sb->s_time_gran = 1;
1127 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1128         sb->s_flags |= MS_POSIXACL;
1129 #endif
1130         sb->s_flags |= MS_I_VERSION;
1131         sb->s_iflags |= SB_I_CGROUPWB;
1132
1133         err = super_setup_bdi(sb);
1134         if (err) {
1135                 btrfs_err(fs_info, "super_setup_bdi failed");
1136                 return err;
1137         }
1138
1139         err = open_ctree(sb, fs_devices, (char *)data);
1140         if (err) {
1141                 btrfs_err(fs_info, "open_ctree failed");
1142                 return err;
1143         }
1144
1145         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1146         key.type = BTRFS_INODE_ITEM_KEY;
1147         key.offset = 0;
1148         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1149         if (IS_ERR(inode)) {
1150                 err = PTR_ERR(inode);
1151                 goto fail_close;
1152         }
1153
1154         sb->s_root = d_make_root(inode);
1155         if (!sb->s_root) {
1156                 err = -ENOMEM;
1157                 goto fail_close;
1158         }
1159
1160         cleancache_init_fs(sb);
1161         sb->s_flags |= MS_ACTIVE;
1162         return 0;
1163
1164 fail_close:
1165         close_ctree(fs_info);
1166         return err;
1167 }
1168
1169 int btrfs_sync_fs(struct super_block *sb, int wait)
1170 {
1171         struct btrfs_trans_handle *trans;
1172         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1173         struct btrfs_root *root = fs_info->tree_root;
1174
1175         trace_btrfs_sync_fs(fs_info, wait);
1176
1177         if (!wait) {
1178                 filemap_flush(fs_info->btree_inode->i_mapping);
1179                 return 0;
1180         }
1181
1182         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1183
1184         trans = btrfs_attach_transaction_barrier(root);
1185         if (IS_ERR(trans)) {
1186                 /* no transaction, don't bother */
1187                 if (PTR_ERR(trans) == -ENOENT) {
1188                         /*
1189                          * Exit unless we have some pending changes
1190                          * that need to go through commit
1191                          */
1192                         if (fs_info->pending_changes == 0)
1193                                 return 0;
1194                         /*
1195                          * A non-blocking test if the fs is frozen. We must not
1196                          * start a new transaction here otherwise a deadlock
1197                          * happens. The pending operations are delayed to the
1198                          * next commit after thawing.
1199                          */
1200                         if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1201                                 __sb_end_write(sb, SB_FREEZE_WRITE);
1202                         else
1203                                 return 0;
1204                         trans = btrfs_start_transaction(root, 0);
1205                 }
1206                 if (IS_ERR(trans))
1207                         return PTR_ERR(trans);
1208         }
1209         return btrfs_commit_transaction(trans);
1210 }
1211
1212 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1213 {
1214         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1215         char *compress_type;
1216
1217         if (btrfs_test_opt(info, DEGRADED))
1218                 seq_puts(seq, ",degraded");
1219         if (btrfs_test_opt(info, NODATASUM))
1220                 seq_puts(seq, ",nodatasum");
1221         if (btrfs_test_opt(info, NODATACOW))
1222                 seq_puts(seq, ",nodatacow");
1223         if (btrfs_test_opt(info, NOBARRIER))
1224                 seq_puts(seq, ",nobarrier");
1225         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1226                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1227         if (info->thread_pool_size !=  min_t(unsigned long,
1228                                              num_online_cpus() + 2, 8))
1229                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1230         if (btrfs_test_opt(info, COMPRESS)) {
1231                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1232                         compress_type = "zlib";
1233                 else
1234                         compress_type = "lzo";
1235                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1236                         seq_printf(seq, ",compress-force=%s", compress_type);
1237                 else
1238                         seq_printf(seq, ",compress=%s", compress_type);
1239         }
1240         if (btrfs_test_opt(info, NOSSD))
1241                 seq_puts(seq, ",nossd");
1242         if (btrfs_test_opt(info, SSD_SPREAD))
1243                 seq_puts(seq, ",ssd_spread");
1244         else if (btrfs_test_opt(info, SSD))
1245                 seq_puts(seq, ",ssd");
1246         if (btrfs_test_opt(info, NOTREELOG))
1247                 seq_puts(seq, ",notreelog");
1248         if (btrfs_test_opt(info, NOLOGREPLAY))
1249                 seq_puts(seq, ",nologreplay");
1250         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1251                 seq_puts(seq, ",flushoncommit");
1252         if (btrfs_test_opt(info, DISCARD))
1253                 seq_puts(seq, ",discard");
1254         if (!(info->sb->s_flags & MS_POSIXACL))
1255                 seq_puts(seq, ",noacl");
1256         if (btrfs_test_opt(info, SPACE_CACHE))
1257                 seq_puts(seq, ",space_cache");
1258         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1259                 seq_puts(seq, ",space_cache=v2");
1260         else
1261                 seq_puts(seq, ",nospace_cache");
1262         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1263                 seq_puts(seq, ",rescan_uuid_tree");
1264         if (btrfs_test_opt(info, CLEAR_CACHE))
1265                 seq_puts(seq, ",clear_cache");
1266         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1267                 seq_puts(seq, ",user_subvol_rm_allowed");
1268         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1269                 seq_puts(seq, ",enospc_debug");
1270         if (btrfs_test_opt(info, AUTO_DEFRAG))
1271                 seq_puts(seq, ",autodefrag");
1272         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1273                 seq_puts(seq, ",inode_cache");
1274         if (btrfs_test_opt(info, SKIP_BALANCE))
1275                 seq_puts(seq, ",skip_balance");
1276 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1277         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1278                 seq_puts(seq, ",check_int_data");
1279         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1280                 seq_puts(seq, ",check_int");
1281         if (info->check_integrity_print_mask)
1282                 seq_printf(seq, ",check_int_print_mask=%d",
1283                                 info->check_integrity_print_mask);
1284 #endif
1285         if (info->metadata_ratio)
1286                 seq_printf(seq, ",metadata_ratio=%d",
1287                                 info->metadata_ratio);
1288         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1289                 seq_puts(seq, ",fatal_errors=panic");
1290         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1291                 seq_printf(seq, ",commit=%d", info->commit_interval);
1292 #ifdef CONFIG_BTRFS_DEBUG
1293         if (btrfs_test_opt(info, FRAGMENT_DATA))
1294                 seq_puts(seq, ",fragment=data");
1295         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1296                 seq_puts(seq, ",fragment=metadata");
1297 #endif
1298         seq_printf(seq, ",subvolid=%llu",
1299                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1300         seq_puts(seq, ",subvol=");
1301         seq_dentry(seq, dentry, " \t\n\\");
1302         return 0;
1303 }
1304
1305 static int btrfs_test_super(struct super_block *s, void *data)
1306 {
1307         struct btrfs_fs_info *p = data;
1308         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1309
1310         return fs_info->fs_devices == p->fs_devices;
1311 }
1312
1313 static int btrfs_set_super(struct super_block *s, void *data)
1314 {
1315         int err = set_anon_super(s, data);
1316         if (!err)
1317                 s->s_fs_info = data;
1318         return err;
1319 }
1320
1321 /*
1322  * subvolumes are identified by ino 256
1323  */
1324 static inline int is_subvolume_inode(struct inode *inode)
1325 {
1326         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1327                 return 1;
1328         return 0;
1329 }
1330
1331 /*
1332  * This will add subvolid=0 to the argument string while removing any subvol=
1333  * and subvolid= arguments to make sure we get the top-level root for path
1334  * walking to the subvol we want.
1335  */
1336 static char *setup_root_args(char *args)
1337 {
1338         char *buf, *dst, *sep;
1339
1340         if (!args)
1341                 return kstrdup("subvolid=0", GFP_KERNEL);
1342
1343         /* The worst case is that we add ",subvolid=0" to the end. */
1344         buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1,
1345                         GFP_KERNEL);
1346         if (!buf)
1347                 return NULL;
1348
1349         while (1) {
1350                 sep = strchrnul(args, ',');
1351                 if (!strstarts(args, "subvol=") &&
1352                     !strstarts(args, "subvolid=")) {
1353                         memcpy(dst, args, sep - args);
1354                         dst += sep - args;
1355                         *dst++ = ',';
1356                 }
1357                 if (*sep)
1358                         args = sep + 1;
1359                 else
1360                         break;
1361         }
1362         strcpy(dst, "subvolid=0");
1363
1364         return buf;
1365 }
1366
1367 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1368                                    int flags, const char *device_name,
1369                                    char *data)
1370 {
1371         struct dentry *root;
1372         struct vfsmount *mnt = NULL;
1373         char *newargs;
1374         int ret;
1375
1376         newargs = setup_root_args(data);
1377         if (!newargs) {
1378                 root = ERR_PTR(-ENOMEM);
1379                 goto out;
1380         }
1381
1382         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1383         if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1384                 if (flags & MS_RDONLY) {
1385                         mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1386                                              device_name, newargs);
1387                 } else {
1388                         mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1389                                              device_name, newargs);
1390                         if (IS_ERR(mnt)) {
1391                                 root = ERR_CAST(mnt);
1392                                 mnt = NULL;
1393                                 goto out;
1394                         }
1395
1396                         down_write(&mnt->mnt_sb->s_umount);
1397                         ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1398                         up_write(&mnt->mnt_sb->s_umount);
1399                         if (ret < 0) {
1400                                 root = ERR_PTR(ret);
1401                                 goto out;
1402                         }
1403                 }
1404         }
1405         if (IS_ERR(mnt)) {
1406                 root = ERR_CAST(mnt);
1407                 mnt = NULL;
1408                 goto out;
1409         }
1410
1411         if (!subvol_name) {
1412                 if (!subvol_objectid) {
1413                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1414                                                           &subvol_objectid);
1415                         if (ret) {
1416                                 root = ERR_PTR(ret);
1417                                 goto out;
1418                         }
1419                 }
1420                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1421                                                             subvol_objectid);
1422                 if (IS_ERR(subvol_name)) {
1423                         root = ERR_CAST(subvol_name);
1424                         subvol_name = NULL;
1425                         goto out;
1426                 }
1427
1428         }
1429
1430         root = mount_subtree(mnt, subvol_name);
1431         /* mount_subtree() drops our reference on the vfsmount. */
1432         mnt = NULL;
1433
1434         if (!IS_ERR(root)) {
1435                 struct super_block *s = root->d_sb;
1436                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1437                 struct inode *root_inode = d_inode(root);
1438                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1439
1440                 ret = 0;
1441                 if (!is_subvolume_inode(root_inode)) {
1442                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1443                                subvol_name);
1444                         ret = -EINVAL;
1445                 }
1446                 if (subvol_objectid && root_objectid != subvol_objectid) {
1447                         /*
1448                          * This will also catch a race condition where a
1449                          * subvolume which was passed by ID is renamed and
1450                          * another subvolume is renamed over the old location.
1451                          */
1452                         btrfs_err(fs_info,
1453                                   "subvol '%s' does not match subvolid %llu",
1454                                   subvol_name, subvol_objectid);
1455                         ret = -EINVAL;
1456                 }
1457                 if (ret) {
1458                         dput(root);
1459                         root = ERR_PTR(ret);
1460                         deactivate_locked_super(s);
1461                 }
1462         }
1463
1464 out:
1465         mntput(mnt);
1466         kfree(newargs);
1467         kfree(subvol_name);
1468         return root;
1469 }
1470
1471 static int parse_security_options(char *orig_opts,
1472                                   struct security_mnt_opts *sec_opts)
1473 {
1474         char *secdata = NULL;
1475         int ret = 0;
1476
1477         secdata = alloc_secdata();
1478         if (!secdata)
1479                 return -ENOMEM;
1480         ret = security_sb_copy_data(orig_opts, secdata);
1481         if (ret) {
1482                 free_secdata(secdata);
1483                 return ret;
1484         }
1485         ret = security_sb_parse_opts_str(secdata, sec_opts);
1486         free_secdata(secdata);
1487         return ret;
1488 }
1489
1490 static int setup_security_options(struct btrfs_fs_info *fs_info,
1491                                   struct super_block *sb,
1492                                   struct security_mnt_opts *sec_opts)
1493 {
1494         int ret = 0;
1495
1496         /*
1497          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1498          * is valid.
1499          */
1500         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1501         if (ret)
1502                 return ret;
1503
1504 #ifdef CONFIG_SECURITY
1505         if (!fs_info->security_opts.num_mnt_opts) {
1506                 /* first time security setup, copy sec_opts to fs_info */
1507                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1508         } else {
1509                 /*
1510                  * Since SELinux (the only one supporting security_mnt_opts)
1511                  * does NOT support changing context during remount/mount of
1512                  * the same sb, this must be the same or part of the same
1513                  * security options, just free it.
1514                  */
1515                 security_free_mnt_opts(sec_opts);
1516         }
1517 #endif
1518         return ret;
1519 }
1520
1521 /*
1522  * Find a superblock for the given device / mount point.
1523  *
1524  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1525  *        for multiple device setup.  Make sure to keep it in sync.
1526  */
1527 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1528                 const char *device_name, void *data)
1529 {
1530         struct block_device *bdev = NULL;
1531         struct super_block *s;
1532         struct btrfs_fs_devices *fs_devices = NULL;
1533         struct btrfs_fs_info *fs_info = NULL;
1534         struct security_mnt_opts new_sec_opts;
1535         fmode_t mode = FMODE_READ;
1536         char *subvol_name = NULL;
1537         u64 subvol_objectid = 0;
1538         int error = 0;
1539
1540         if (!(flags & MS_RDONLY))
1541                 mode |= FMODE_WRITE;
1542
1543         error = btrfs_parse_early_options(data, mode, fs_type,
1544                                           &subvol_name, &subvol_objectid,
1545                                           &fs_devices);
1546         if (error) {
1547                 kfree(subvol_name);
1548                 return ERR_PTR(error);
1549         }
1550
1551         if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1552                 /* mount_subvol() will free subvol_name. */
1553                 return mount_subvol(subvol_name, subvol_objectid, flags,
1554                                     device_name, data);
1555         }
1556
1557         security_init_mnt_opts(&new_sec_opts);
1558         if (data) {
1559                 error = parse_security_options(data, &new_sec_opts);
1560                 if (error)
1561                         return ERR_PTR(error);
1562         }
1563
1564         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1565         if (error)
1566                 goto error_sec_opts;
1567
1568         /*
1569          * Setup a dummy root and fs_info for test/set super.  This is because
1570          * we don't actually fill this stuff out until open_ctree, but we need
1571          * it for searching for existing supers, so this lets us do that and
1572          * then open_ctree will properly initialize everything later.
1573          */
1574         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1575         if (!fs_info) {
1576                 error = -ENOMEM;
1577                 goto error_sec_opts;
1578         }
1579
1580         fs_info->fs_devices = fs_devices;
1581
1582         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1583         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1584         security_init_mnt_opts(&fs_info->security_opts);
1585         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1586                 error = -ENOMEM;
1587                 goto error_fs_info;
1588         }
1589
1590         error = btrfs_open_devices(fs_devices, mode, fs_type);
1591         if (error)
1592                 goto error_fs_info;
1593
1594         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1595                 error = -EACCES;
1596                 goto error_close_devices;
1597         }
1598
1599         bdev = fs_devices->latest_bdev;
1600         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1601                  fs_info);
1602         if (IS_ERR(s)) {
1603                 error = PTR_ERR(s);
1604                 goto error_close_devices;
1605         }
1606
1607         if (s->s_root) {
1608                 btrfs_close_devices(fs_devices);
1609                 free_fs_info(fs_info);
1610                 if ((flags ^ s->s_flags) & MS_RDONLY)
1611                         error = -EBUSY;
1612         } else {
1613                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1614                 btrfs_sb(s)->bdev_holder = fs_type;
1615                 error = btrfs_fill_super(s, fs_devices, data);
1616         }
1617         if (error) {
1618                 deactivate_locked_super(s);
1619                 goto error_sec_opts;
1620         }
1621
1622         fs_info = btrfs_sb(s);
1623         error = setup_security_options(fs_info, s, &new_sec_opts);
1624         if (error) {
1625                 deactivate_locked_super(s);
1626                 goto error_sec_opts;
1627         }
1628
1629         return dget(s->s_root);
1630
1631 error_close_devices:
1632         btrfs_close_devices(fs_devices);
1633 error_fs_info:
1634         free_fs_info(fs_info);
1635 error_sec_opts:
1636         security_free_mnt_opts(&new_sec_opts);
1637         return ERR_PTR(error);
1638 }
1639
1640 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1641                                      int new_pool_size, int old_pool_size)
1642 {
1643         if (new_pool_size == old_pool_size)
1644                 return;
1645
1646         fs_info->thread_pool_size = new_pool_size;
1647
1648         btrfs_info(fs_info, "resize thread pool %d -> %d",
1649                old_pool_size, new_pool_size);
1650
1651         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1652         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1653         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1654         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1655         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1656         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1657         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1658                                 new_pool_size);
1659         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1660         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1661         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1662         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1663         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1664                                 new_pool_size);
1665 }
1666
1667 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1668 {
1669         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1670 }
1671
1672 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1673                                        unsigned long old_opts, int flags)
1674 {
1675         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1676             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1677              (flags & MS_RDONLY))) {
1678                 /* wait for any defraggers to finish */
1679                 wait_event(fs_info->transaction_wait,
1680                            (atomic_read(&fs_info->defrag_running) == 0));
1681                 if (flags & MS_RDONLY)
1682                         sync_filesystem(fs_info->sb);
1683         }
1684 }
1685
1686 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1687                                          unsigned long old_opts)
1688 {
1689         /*
1690          * We need to cleanup all defragable inodes if the autodefragment is
1691          * close or the filesystem is read only.
1692          */
1693         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1694             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1695              (fs_info->sb->s_flags & MS_RDONLY))) {
1696                 btrfs_cleanup_defrag_inodes(fs_info);
1697         }
1698
1699         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1700 }
1701
1702 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1703 {
1704         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1705         struct btrfs_root *root = fs_info->tree_root;
1706         unsigned old_flags = sb->s_flags;
1707         unsigned long old_opts = fs_info->mount_opt;
1708         unsigned long old_compress_type = fs_info->compress_type;
1709         u64 old_max_inline = fs_info->max_inline;
1710         int old_thread_pool_size = fs_info->thread_pool_size;
1711         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1712         int ret;
1713
1714         sync_filesystem(sb);
1715         btrfs_remount_prepare(fs_info);
1716
1717         if (data) {
1718                 struct security_mnt_opts new_sec_opts;
1719
1720                 security_init_mnt_opts(&new_sec_opts);
1721                 ret = parse_security_options(data, &new_sec_opts);
1722                 if (ret)
1723                         goto restore;
1724                 ret = setup_security_options(fs_info, sb,
1725                                              &new_sec_opts);
1726                 if (ret) {
1727                         security_free_mnt_opts(&new_sec_opts);
1728                         goto restore;
1729                 }
1730         }
1731
1732         ret = btrfs_parse_options(fs_info, data, *flags);
1733         if (ret) {
1734                 ret = -EINVAL;
1735                 goto restore;
1736         }
1737
1738         btrfs_remount_begin(fs_info, old_opts, *flags);
1739         btrfs_resize_thread_pool(fs_info,
1740                 fs_info->thread_pool_size, old_thread_pool_size);
1741
1742         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1743                 goto out;
1744
1745         if (*flags & MS_RDONLY) {
1746                 /*
1747                  * this also happens on 'umount -rf' or on shutdown, when
1748                  * the filesystem is busy.
1749                  */
1750                 cancel_work_sync(&fs_info->async_reclaim_work);
1751
1752                 /* wait for the uuid_scan task to finish */
1753                 down(&fs_info->uuid_tree_rescan_sem);
1754                 /* avoid complains from lockdep et al. */
1755                 up(&fs_info->uuid_tree_rescan_sem);
1756
1757                 sb->s_flags |= MS_RDONLY;
1758
1759                 /*
1760                  * Setting MS_RDONLY will put the cleaner thread to
1761                  * sleep at the next loop if it's already active.
1762                  * If it's already asleep, we'll leave unused block
1763                  * groups on disk until we're mounted read-write again
1764                  * unless we clean them up here.
1765                  */
1766                 btrfs_delete_unused_bgs(fs_info);
1767
1768                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1769                 btrfs_scrub_cancel(fs_info);
1770                 btrfs_pause_balance(fs_info);
1771
1772                 ret = btrfs_commit_super(fs_info);
1773                 if (ret)
1774                         goto restore;
1775         } else {
1776                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1777                         btrfs_err(fs_info,
1778                                 "Remounting read-write after error is not allowed");
1779                         ret = -EINVAL;
1780                         goto restore;
1781                 }
1782                 if (fs_info->fs_devices->rw_devices == 0) {
1783                         ret = -EACCES;
1784                         goto restore;
1785                 }
1786
1787                 if (!btrfs_check_rw_degradable(fs_info)) {
1788                         btrfs_warn(fs_info,
1789                                 "too many missing devices, writeable remount is not allowed");
1790                         ret = -EACCES;
1791                         goto restore;
1792                 }
1793
1794                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1795                         ret = -EINVAL;
1796                         goto restore;
1797                 }
1798
1799                 ret = btrfs_cleanup_fs_roots(fs_info);
1800                 if (ret)
1801                         goto restore;
1802
1803                 /* recover relocation */
1804                 mutex_lock(&fs_info->cleaner_mutex);
1805                 ret = btrfs_recover_relocation(root);
1806                 mutex_unlock(&fs_info->cleaner_mutex);
1807                 if (ret)
1808                         goto restore;
1809
1810                 ret = btrfs_resume_balance_async(fs_info);
1811                 if (ret)
1812                         goto restore;
1813
1814                 ret = btrfs_resume_dev_replace_async(fs_info);
1815                 if (ret) {
1816                         btrfs_warn(fs_info, "failed to resume dev_replace");
1817                         goto restore;
1818                 }
1819
1820                 btrfs_qgroup_rescan_resume(fs_info);
1821
1822                 if (!fs_info->uuid_root) {
1823                         btrfs_info(fs_info, "creating UUID tree");
1824                         ret = btrfs_create_uuid_tree(fs_info);
1825                         if (ret) {
1826                                 btrfs_warn(fs_info,
1827                                            "failed to create the UUID tree %d",
1828                                            ret);
1829                                 goto restore;
1830                         }
1831                 }
1832                 sb->s_flags &= ~MS_RDONLY;
1833
1834                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1835         }
1836 out:
1837         wake_up_process(fs_info->transaction_kthread);
1838         btrfs_remount_cleanup(fs_info, old_opts);
1839         return 0;
1840
1841 restore:
1842         /* We've hit an error - don't reset MS_RDONLY */
1843         if (sb->s_flags & MS_RDONLY)
1844                 old_flags |= MS_RDONLY;
1845         sb->s_flags = old_flags;
1846         fs_info->mount_opt = old_opts;
1847         fs_info->compress_type = old_compress_type;
1848         fs_info->max_inline = old_max_inline;
1849         btrfs_resize_thread_pool(fs_info,
1850                 old_thread_pool_size, fs_info->thread_pool_size);
1851         fs_info->metadata_ratio = old_metadata_ratio;
1852         btrfs_remount_cleanup(fs_info, old_opts);
1853         return ret;
1854 }
1855
1856 /* Used to sort the devices by max_avail(descending sort) */
1857 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1858                                        const void *dev_info2)
1859 {
1860         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1861             ((struct btrfs_device_info *)dev_info2)->max_avail)
1862                 return -1;
1863         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1864                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1865                 return 1;
1866         else
1867         return 0;
1868 }
1869
1870 /*
1871  * sort the devices by max_avail, in which max free extent size of each device
1872  * is stored.(Descending Sort)
1873  */
1874 static inline void btrfs_descending_sort_devices(
1875                                         struct btrfs_device_info *devices,
1876                                         size_t nr_devices)
1877 {
1878         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1879              btrfs_cmp_device_free_bytes, NULL);
1880 }
1881
1882 /*
1883  * The helper to calc the free space on the devices that can be used to store
1884  * file data.
1885  */
1886 static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1887                                        u64 *free_bytes)
1888 {
1889         struct btrfs_device_info *devices_info;
1890         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1891         struct btrfs_device *device;
1892         u64 skip_space;
1893         u64 type;
1894         u64 avail_space;
1895         u64 min_stripe_size;
1896         int min_stripes = 1, num_stripes = 1;
1897         int i = 0, nr_devices;
1898
1899         /*
1900          * We aren't under the device list lock, so this is racy-ish, but good
1901          * enough for our purposes.
1902          */
1903         nr_devices = fs_info->fs_devices->open_devices;
1904         if (!nr_devices) {
1905                 smp_mb();
1906                 nr_devices = fs_info->fs_devices->open_devices;
1907                 ASSERT(nr_devices);
1908                 if (!nr_devices) {
1909                         *free_bytes = 0;
1910                         return 0;
1911                 }
1912         }
1913
1914         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1915                                GFP_KERNEL);
1916         if (!devices_info)
1917                 return -ENOMEM;
1918
1919         /* calc min stripe number for data space allocation */
1920         type = btrfs_data_alloc_profile(fs_info);
1921         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1922                 min_stripes = 2;
1923                 num_stripes = nr_devices;
1924         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1925                 min_stripes = 2;
1926                 num_stripes = 2;
1927         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1928                 min_stripes = 4;
1929                 num_stripes = 4;
1930         }
1931
1932         if (type & BTRFS_BLOCK_GROUP_DUP)
1933                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1934         else
1935                 min_stripe_size = BTRFS_STRIPE_LEN;
1936
1937         rcu_read_lock();
1938         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1939                 if (!device->in_fs_metadata || !device->bdev ||
1940                     device->is_tgtdev_for_dev_replace)
1941                         continue;
1942
1943                 if (i >= nr_devices)
1944                         break;
1945
1946                 avail_space = device->total_bytes - device->bytes_used;
1947
1948                 /* align with stripe_len */
1949                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1950                 avail_space *= BTRFS_STRIPE_LEN;
1951
1952                 /*
1953                  * In order to avoid overwriting the superblock on the drive,
1954                  * btrfs starts at an offset of at least 1MB when doing chunk
1955                  * allocation.
1956                  */
1957                 skip_space = SZ_1M;
1958
1959                 /*
1960                  * we can use the free space in [0, skip_space - 1], subtract
1961                  * it from the total.
1962                  */
1963                 if (avail_space && avail_space >= skip_space)
1964                         avail_space -= skip_space;
1965                 else
1966                         avail_space = 0;
1967
1968                 if (avail_space < min_stripe_size)
1969                         continue;
1970
1971                 devices_info[i].dev = device;
1972                 devices_info[i].max_avail = avail_space;
1973
1974                 i++;
1975         }
1976         rcu_read_unlock();
1977
1978         nr_devices = i;
1979
1980         btrfs_descending_sort_devices(devices_info, nr_devices);
1981
1982         i = nr_devices - 1;
1983         avail_space = 0;
1984         while (nr_devices >= min_stripes) {
1985                 if (num_stripes > nr_devices)
1986                         num_stripes = nr_devices;
1987
1988                 if (devices_info[i].max_avail >= min_stripe_size) {
1989                         int j;
1990                         u64 alloc_size;
1991
1992                         avail_space += devices_info[i].max_avail * num_stripes;
1993                         alloc_size = devices_info[i].max_avail;
1994                         for (j = i + 1 - num_stripes; j <= i; j++)
1995                                 devices_info[j].max_avail -= alloc_size;
1996                 }
1997                 i--;
1998                 nr_devices--;
1999         }
2000
2001         kfree(devices_info);
2002         *free_bytes = avail_space;
2003         return 0;
2004 }
2005
2006 /*
2007  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2008  *
2009  * If there's a redundant raid level at DATA block groups, use the respective
2010  * multiplier to scale the sizes.
2011  *
2012  * Unused device space usage is based on simulating the chunk allocator
2013  * algorithm that respects the device sizes and order of allocations.  This is
2014  * a close approximation of the actual use but there are other factors that may
2015  * change the result (like a new metadata chunk).
2016  *
2017  * If metadata is exhausted, f_bavail will be 0.
2018  */
2019 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2020 {
2021         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2022         struct btrfs_super_block *disk_super = fs_info->super_copy;
2023         struct list_head *head = &fs_info->space_info;
2024         struct btrfs_space_info *found;
2025         u64 total_used = 0;
2026         u64 total_free_data = 0;
2027         u64 total_free_meta = 0;
2028         int bits = dentry->d_sb->s_blocksize_bits;
2029         __be32 *fsid = (__be32 *)fs_info->fsid;
2030         unsigned factor = 1;
2031         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2032         int ret;
2033         u64 thresh = 0;
2034         int mixed = 0;
2035
2036         rcu_read_lock();
2037         list_for_each_entry_rcu(found, head, list) {
2038                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2039                         int i;
2040
2041                         total_free_data += found->disk_total - found->disk_used;
2042                         total_free_data -=
2043                                 btrfs_account_ro_block_groups_free_space(found);
2044
2045                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2046                                 if (!list_empty(&found->block_groups[i])) {
2047                                         switch (i) {
2048                                         case BTRFS_RAID_DUP:
2049                                         case BTRFS_RAID_RAID1:
2050                                         case BTRFS_RAID_RAID10:
2051                                                 factor = 2;
2052                                         }
2053                                 }
2054                         }
2055                 }
2056
2057                 /*
2058                  * Metadata in mixed block goup profiles are accounted in data
2059                  */
2060                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2061                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2062                                 mixed = 1;
2063                         else
2064                                 total_free_meta += found->disk_total -
2065                                         found->disk_used;
2066                 }
2067
2068                 total_used += found->disk_used;
2069         }
2070
2071         rcu_read_unlock();
2072
2073         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2074         buf->f_blocks >>= bits;
2075         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2076
2077         /* Account global block reserve as used, it's in logical size already */
2078         spin_lock(&block_rsv->lock);
2079         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2080         if (buf->f_bfree >= block_rsv->size >> bits)
2081                 buf->f_bfree -= block_rsv->size >> bits;
2082         else
2083                 buf->f_bfree = 0;
2084         spin_unlock(&block_rsv->lock);
2085
2086         buf->f_bavail = div_u64(total_free_data, factor);
2087         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2088         if (ret)
2089                 return ret;
2090         buf->f_bavail += div_u64(total_free_data, factor);
2091         buf->f_bavail = buf->f_bavail >> bits;
2092
2093         /*
2094          * We calculate the remaining metadata space minus global reserve. If
2095          * this is (supposedly) smaller than zero, there's no space. But this
2096          * does not hold in practice, the exhausted state happens where's still
2097          * some positive delta. So we apply some guesswork and compare the
2098          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2099          *
2100          * We probably cannot calculate the exact threshold value because this
2101          * depends on the internal reservations requested by various
2102          * operations, so some operations that consume a few metadata will
2103          * succeed even if the Avail is zero. But this is better than the other
2104          * way around.
2105          */
2106         thresh = 4 * 1024 * 1024;
2107
2108         if (!mixed && total_free_meta - thresh < block_rsv->size)
2109                 buf->f_bavail = 0;
2110
2111         buf->f_type = BTRFS_SUPER_MAGIC;
2112         buf->f_bsize = dentry->d_sb->s_blocksize;
2113         buf->f_namelen = BTRFS_NAME_LEN;
2114
2115         /* We treat it as constant endianness (it doesn't matter _which_)
2116            because we want the fsid to come out the same whether mounted
2117            on a big-endian or little-endian host */
2118         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2119         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2120         /* Mask in the root object ID too, to disambiguate subvols */
2121         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2122         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2123
2124         return 0;
2125 }
2126
2127 static void btrfs_kill_super(struct super_block *sb)
2128 {
2129         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2130         kill_anon_super(sb);
2131         free_fs_info(fs_info);
2132 }
2133
2134 static struct file_system_type btrfs_fs_type = {
2135         .owner          = THIS_MODULE,
2136         .name           = "btrfs",
2137         .mount          = btrfs_mount,
2138         .kill_sb        = btrfs_kill_super,
2139         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2140 };
2141 MODULE_ALIAS_FS("btrfs");
2142
2143 static int btrfs_control_open(struct inode *inode, struct file *file)
2144 {
2145         /*
2146          * The control file's private_data is used to hold the
2147          * transaction when it is started and is used to keep
2148          * track of whether a transaction is already in progress.
2149          */
2150         file->private_data = NULL;
2151         return 0;
2152 }
2153
2154 /*
2155  * used by btrfsctl to scan devices when no FS is mounted
2156  */
2157 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2158                                 unsigned long arg)
2159 {
2160         struct btrfs_ioctl_vol_args *vol;
2161         struct btrfs_fs_devices *fs_devices;
2162         int ret = -ENOTTY;
2163
2164         if (!capable(CAP_SYS_ADMIN))
2165                 return -EPERM;
2166
2167         vol = memdup_user((void __user *)arg, sizeof(*vol));
2168         if (IS_ERR(vol))
2169                 return PTR_ERR(vol);
2170
2171         switch (cmd) {
2172         case BTRFS_IOC_SCAN_DEV:
2173                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2174                                             &btrfs_fs_type, &fs_devices);
2175                 break;
2176         case BTRFS_IOC_DEVICES_READY:
2177                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2178                                             &btrfs_fs_type, &fs_devices);
2179                 if (ret)
2180                         break;
2181                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2182                 break;
2183         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2184                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2185                 break;
2186         }
2187
2188         kfree(vol);
2189         return ret;
2190 }
2191
2192 static int btrfs_freeze(struct super_block *sb)
2193 {
2194         struct btrfs_trans_handle *trans;
2195         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2196         struct btrfs_root *root = fs_info->tree_root;
2197
2198         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2199         /*
2200          * We don't need a barrier here, we'll wait for any transaction that
2201          * could be in progress on other threads (and do delayed iputs that
2202          * we want to avoid on a frozen filesystem), or do the commit
2203          * ourselves.
2204          */
2205         trans = btrfs_attach_transaction_barrier(root);
2206         if (IS_ERR(trans)) {
2207                 /* no transaction, don't bother */
2208                 if (PTR_ERR(trans) == -ENOENT)
2209                         return 0;
2210                 return PTR_ERR(trans);
2211         }
2212         return btrfs_commit_transaction(trans);
2213 }
2214
2215 static int btrfs_unfreeze(struct super_block *sb)
2216 {
2217         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2218
2219         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2220         return 0;
2221 }
2222
2223 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2224 {
2225         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2226         struct btrfs_fs_devices *cur_devices;
2227         struct btrfs_device *dev, *first_dev = NULL;
2228         struct list_head *head;
2229         struct rcu_string *name;
2230
2231         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2232         cur_devices = fs_info->fs_devices;
2233         while (cur_devices) {
2234                 head = &cur_devices->devices;
2235                 list_for_each_entry(dev, head, dev_list) {
2236                         if (dev->missing)
2237                                 continue;
2238                         if (!dev->name)
2239                                 continue;
2240                         if (!first_dev || dev->devid < first_dev->devid)
2241                                 first_dev = dev;
2242                 }
2243                 cur_devices = cur_devices->seed;
2244         }
2245
2246         if (first_dev) {
2247                 rcu_read_lock();
2248                 name = rcu_dereference(first_dev->name);
2249                 seq_escape(m, name->str, " \t\n\\");
2250                 rcu_read_unlock();
2251         } else {
2252                 WARN_ON(1);
2253         }
2254         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2255         return 0;
2256 }
2257
2258 static const struct super_operations btrfs_super_ops = {
2259         .drop_inode     = btrfs_drop_inode,
2260         .evict_inode    = btrfs_evict_inode,
2261         .put_super      = btrfs_put_super,
2262         .sync_fs        = btrfs_sync_fs,
2263         .show_options   = btrfs_show_options,
2264         .show_devname   = btrfs_show_devname,
2265         .write_inode    = btrfs_write_inode,
2266         .alloc_inode    = btrfs_alloc_inode,
2267         .destroy_inode  = btrfs_destroy_inode,
2268         .statfs         = btrfs_statfs,
2269         .remount_fs     = btrfs_remount,
2270         .freeze_fs      = btrfs_freeze,
2271         .unfreeze_fs    = btrfs_unfreeze,
2272 };
2273
2274 static const struct file_operations btrfs_ctl_fops = {
2275         .open = btrfs_control_open,
2276         .unlocked_ioctl  = btrfs_control_ioctl,
2277         .compat_ioctl = btrfs_control_ioctl,
2278         .owner   = THIS_MODULE,
2279         .llseek = noop_llseek,
2280 };
2281
2282 static struct miscdevice btrfs_misc = {
2283         .minor          = BTRFS_MINOR,
2284         .name           = "btrfs-control",
2285         .fops           = &btrfs_ctl_fops
2286 };
2287
2288 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2289 MODULE_ALIAS("devname:btrfs-control");
2290
2291 static int btrfs_interface_init(void)
2292 {
2293         return misc_register(&btrfs_misc);
2294 }
2295
2296 static void btrfs_interface_exit(void)
2297 {
2298         misc_deregister(&btrfs_misc);
2299 }
2300
2301 static void btrfs_print_mod_info(void)
2302 {
2303         pr_info("Btrfs loaded, crc32c=%s"
2304 #ifdef CONFIG_BTRFS_DEBUG
2305                         ", debug=on"
2306 #endif
2307 #ifdef CONFIG_BTRFS_ASSERT
2308                         ", assert=on"
2309 #endif
2310 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2311                         ", integrity-checker=on"
2312 #endif
2313                         "\n",
2314                         btrfs_crc32c_impl());
2315 }
2316
2317 static int __init init_btrfs_fs(void)
2318 {
2319         int err;
2320
2321         err = btrfs_hash_init();
2322         if (err)
2323                 return err;
2324
2325         btrfs_props_init();
2326
2327         err = btrfs_init_sysfs();
2328         if (err)
2329                 goto free_hash;
2330
2331         btrfs_init_compress();
2332
2333         err = btrfs_init_cachep();
2334         if (err)
2335                 goto free_compress;
2336
2337         err = extent_io_init();
2338         if (err)
2339                 goto free_cachep;
2340
2341         err = extent_map_init();
2342         if (err)
2343                 goto free_extent_io;
2344
2345         err = ordered_data_init();
2346         if (err)
2347                 goto free_extent_map;
2348
2349         err = btrfs_delayed_inode_init();
2350         if (err)
2351                 goto free_ordered_data;
2352
2353         err = btrfs_auto_defrag_init();
2354         if (err)
2355                 goto free_delayed_inode;
2356
2357         err = btrfs_delayed_ref_init();
2358         if (err)
2359                 goto free_auto_defrag;
2360
2361         err = btrfs_prelim_ref_init();
2362         if (err)
2363                 goto free_delayed_ref;
2364
2365         err = btrfs_end_io_wq_init();
2366         if (err)
2367                 goto free_prelim_ref;
2368
2369         err = btrfs_interface_init();
2370         if (err)
2371                 goto free_end_io_wq;
2372
2373         btrfs_init_lockdep();
2374
2375         btrfs_print_mod_info();
2376
2377         err = btrfs_run_sanity_tests();
2378         if (err)
2379                 goto unregister_ioctl;
2380
2381         err = register_filesystem(&btrfs_fs_type);
2382         if (err)
2383                 goto unregister_ioctl;
2384
2385         return 0;
2386
2387 unregister_ioctl:
2388         btrfs_interface_exit();
2389 free_end_io_wq:
2390         btrfs_end_io_wq_exit();
2391 free_prelim_ref:
2392         btrfs_prelim_ref_exit();
2393 free_delayed_ref:
2394         btrfs_delayed_ref_exit();
2395 free_auto_defrag:
2396         btrfs_auto_defrag_exit();
2397 free_delayed_inode:
2398         btrfs_delayed_inode_exit();
2399 free_ordered_data:
2400         ordered_data_exit();
2401 free_extent_map:
2402         extent_map_exit();
2403 free_extent_io:
2404         extent_io_exit();
2405 free_cachep:
2406         btrfs_destroy_cachep();
2407 free_compress:
2408         btrfs_exit_compress();
2409         btrfs_exit_sysfs();
2410 free_hash:
2411         btrfs_hash_exit();
2412         return err;
2413 }
2414
2415 static void __exit exit_btrfs_fs(void)
2416 {
2417         btrfs_destroy_cachep();
2418         btrfs_delayed_ref_exit();
2419         btrfs_auto_defrag_exit();
2420         btrfs_delayed_inode_exit();
2421         btrfs_prelim_ref_exit();
2422         ordered_data_exit();
2423         extent_map_exit();
2424         extent_io_exit();
2425         btrfs_interface_exit();
2426         btrfs_end_io_wq_exit();
2427         unregister_filesystem(&btrfs_fs_type);
2428         btrfs_exit_sysfs();
2429         btrfs_cleanup_fs_uuids();
2430         btrfs_exit_compress();
2431         btrfs_hash_exit();
2432 }
2433
2434 late_initcall(init_btrfs_fs);
2435 module_exit(exit_btrfs_fs)
2436
2437 MODULE_LICENSE("GPL");