fs/btrfs/super.c

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