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;
1175         char *newargs;
1176
1177         newargs = setup_root_args(data);
1178         if (!newargs)
1179                 return ERR_PTR(-ENOMEM);
1180         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
1181                              newargs);
1182
1183         if (PTR_RET(mnt) == -EBUSY) {
1184                 if (flags & MS_RDONLY) {
1185                         mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY, device_name,
1186                                              newargs);
1187                 } else {
1188                         int r;
1189                         mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY, device_name,
1190                                              newargs);
1191                         if (IS_ERR(mnt)) {
1192                                 kfree(newargs);
1193                                 return ERR_CAST(mnt);
1194                         }
1195
1196                         down_write(&mnt->mnt_sb->s_umount);
1197                         r = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1198                         up_write(&mnt->mnt_sb->s_umount);
1199                         if (r < 0) {
1200                                 /* FIXME: release vfsmount mnt ??*/
1201                                 kfree(newargs);
1202                                 return ERR_PTR(r);
1203                         }
1204                 }
1205         }
1206
1207         kfree(newargs);
1208
1209         if (IS_ERR(mnt))
1210                 return ERR_CAST(mnt);
1211
1212         root = mount_subtree(mnt, subvol_name);
1213
1214         if (!IS_ERR(root) && !is_subvolume_inode(d_inode(root))) {
1215                 struct super_block *s = root->d_sb;
1216                 dput(root);
1217                 root = ERR_PTR(-EINVAL);
1218                 deactivate_locked_super(s);
1219                 printk(KERN_ERR "BTRFS: '%s' is not a valid subvolume\n",
1220                                 subvol_name);
1221         }
1222
1223         return root;
1224 }
1225
1226 static int parse_security_options(char *orig_opts,
1227                                   struct security_mnt_opts *sec_opts)
1228 {
1229         char *secdata = NULL;
1230         int ret = 0;
1231
1232         secdata = alloc_secdata();
1233         if (!secdata)
1234                 return -ENOMEM;
1235         ret = security_sb_copy_data(orig_opts, secdata);
1236         if (ret) {
1237                 free_secdata(secdata);
1238                 return ret;
1239         }
1240         ret = security_sb_parse_opts_str(secdata, sec_opts);
1241         free_secdata(secdata);
1242         return ret;
1243 }
1244
1245 static int setup_security_options(struct btrfs_fs_info *fs_info,
1246                                   struct super_block *sb,
1247                                   struct security_mnt_opts *sec_opts)
1248 {
1249         int ret = 0;
1250
1251         /*
1252          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1253          * is valid.
1254          */
1255         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1256         if (ret)
1257                 return ret;
1258
1259 #ifdef CONFIG_SECURITY
1260         if (!fs_info->security_opts.num_mnt_opts) {
1261                 /* first time security setup, copy sec_opts to fs_info */
1262                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1263         } else {
1264                 /*
1265                  * Since SELinux(the only one supports security_mnt_opts) does
1266                  * NOT support changing context during remount/mount same sb,
1267                  * This must be the same or part of the same security options,
1268                  * just free it.
1269                  */
1270                 security_free_mnt_opts(sec_opts);
1271         }
1272 #endif
1273         return ret;
1274 }
1275
1276 /*
1277  * Find a superblock for the given device / mount point.
1278  *
1279  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1280  *        for multiple device setup.  Make sure to keep it in sync.
1281  */
1282 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1283                 const char *device_name, void *data)
1284 {
1285         struct block_device *bdev = NULL;
1286         struct super_block *s;
1287         struct dentry *root;
1288         struct btrfs_fs_devices *fs_devices = NULL;
1289         struct btrfs_fs_info *fs_info = NULL;
1290         struct security_mnt_opts new_sec_opts;
1291         fmode_t mode = FMODE_READ;
1292         char *subvol_name = NULL;
1293         u64 subvol_objectid = 0;
1294         int error = 0;
1295
1296         if (!(flags & MS_RDONLY))
1297                 mode |= FMODE_WRITE;
1298
1299         error = btrfs_parse_early_options(data, mode, fs_type,
1300                                           &subvol_name, &subvol_objectid,
1301                                           &fs_devices);
1302         if (error) {
1303                 kfree(subvol_name);
1304                 return ERR_PTR(error);
1305         }
1306
1307         if (subvol_name) {
1308                 root = mount_subvol(subvol_name, flags, device_name, data);
1309                 kfree(subvol_name);
1310                 return root;
1311         }
1312
1313         security_init_mnt_opts(&new_sec_opts);
1314         if (data) {
1315                 error = parse_security_options(data, &new_sec_opts);
1316                 if (error)
1317                         return ERR_PTR(error);
1318         }
1319
1320         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1321         if (error)
1322                 goto error_sec_opts;
1323
1324         /*
1325          * Setup a dummy root and fs_info for test/set super.  This is because
1326          * we don't actually fill this stuff out until open_ctree, but we need
1327          * it for searching for existing supers, so this lets us do that and
1328          * then open_ctree will properly initialize everything later.
1329          */
1330         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1331         if (!fs_info) {
1332                 error = -ENOMEM;
1333                 goto error_sec_opts;
1334         }
1335
1336         fs_info->fs_devices = fs_devices;
1337
1338         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1339         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1340         security_init_mnt_opts(&fs_info->security_opts);
1341         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1342                 error = -ENOMEM;
1343                 goto error_fs_info;
1344         }
1345
1346         error = btrfs_open_devices(fs_devices, mode, fs_type);
1347         if (error)
1348                 goto error_fs_info;
1349
1350         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1351                 error = -EACCES;
1352                 goto error_close_devices;
1353         }
1354
1355         bdev = fs_devices->latest_bdev;
1356         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1357                  fs_info);
1358         if (IS_ERR(s)) {
1359                 error = PTR_ERR(s);
1360                 goto error_close_devices;
1361         }
1362
1363         if (s->s_root) {
1364                 btrfs_close_devices(fs_devices);
1365                 free_fs_info(fs_info);
1366                 if ((flags ^ s->s_flags) & MS_RDONLY)
1367                         error = -EBUSY;
1368         } else {
1369                 char b[BDEVNAME_SIZE];
1370
1371                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1372                 btrfs_sb(s)->bdev_holder = fs_type;
1373                 error = btrfs_fill_super(s, fs_devices, data,
1374                                          flags & MS_SILENT ? 1 : 0);
1375         }
1376
1377         root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
1378         if (IS_ERR(root)) {
1379                 deactivate_locked_super(s);
1380                 error = PTR_ERR(root);
1381                 goto error_sec_opts;
1382         }
1383
1384         fs_info = btrfs_sb(s);
1385         error = setup_security_options(fs_info, s, &new_sec_opts);
1386         if (error) {
1387                 dput(root);
1388                 deactivate_locked_super(s);
1389                 goto error_sec_opts;
1390         }
1391
1392         return root;
1393
1394 error_close_devices:
1395         btrfs_close_devices(fs_devices);
1396 error_fs_info:
1397         free_fs_info(fs_info);
1398 error_sec_opts:
1399         security_free_mnt_opts(&new_sec_opts);
1400         return ERR_PTR(error);
1401 }
1402
1403 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1404                                      int new_pool_size, int old_pool_size)
1405 {
1406         if (new_pool_size == old_pool_size)
1407                 return;
1408
1409         fs_info->thread_pool_size = new_pool_size;
1410
1411         btrfs_info(fs_info, "resize thread pool %d -> %d",
1412                old_pool_size, new_pool_size);
1413
1414         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1415         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1416         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1417         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1418         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1419         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1420         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1421                                 new_pool_size);
1422         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1423         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1424         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1425         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1426         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1427                                 new_pool_size);
1428 }
1429
1430 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1431 {
1432         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1433 }
1434
1435 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1436                                        unsigned long old_opts, int flags)
1437 {
1438         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1439             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1440              (flags & MS_RDONLY))) {
1441                 /* wait for any defraggers to finish */
1442                 wait_event(fs_info->transaction_wait,
1443                            (atomic_read(&fs_info->defrag_running) == 0));
1444                 if (flags & MS_RDONLY)
1445                         sync_filesystem(fs_info->sb);
1446         }
1447 }
1448
1449 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1450                                          unsigned long old_opts)
1451 {
1452         /*
1453          * We need cleanup all defragable inodes if the autodefragment is
1454          * close or the fs is R/O.
1455          */
1456         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1457             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1458              (fs_info->sb->s_flags & MS_RDONLY))) {
1459                 btrfs_cleanup_defrag_inodes(fs_info);
1460         }
1461
1462         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1463 }
1464
1465 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1466 {
1467         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1468         struct btrfs_root *root = fs_info->tree_root;
1469         unsigned old_flags = sb->s_flags;
1470         unsigned long old_opts = fs_info->mount_opt;
1471         unsigned long old_compress_type = fs_info->compress_type;
1472         u64 old_max_inline = fs_info->max_inline;
1473         u64 old_alloc_start = fs_info->alloc_start;
1474         int old_thread_pool_size = fs_info->thread_pool_size;
1475         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1476         int ret;
1477
1478         sync_filesystem(sb);
1479         btrfs_remount_prepare(fs_info);
1480
1481         if (data) {
1482                 struct security_mnt_opts new_sec_opts;
1483
1484                 security_init_mnt_opts(&new_sec_opts);
1485                 ret = parse_security_options(data, &new_sec_opts);
1486                 if (ret)
1487                         goto restore;
1488                 ret = setup_security_options(fs_info, sb,
1489                                              &new_sec_opts);
1490                 if (ret) {
1491                         security_free_mnt_opts(&new_sec_opts);
1492                         goto restore;
1493                 }
1494         }
1495
1496         ret = btrfs_parse_options(root, data);
1497         if (ret) {
1498                 ret = -EINVAL;
1499                 goto restore;
1500         }
1501
1502         btrfs_remount_begin(fs_info, old_opts, *flags);
1503         btrfs_resize_thread_pool(fs_info,
1504                 fs_info->thread_pool_size, old_thread_pool_size);
1505
1506         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1507                 goto out;
1508
1509         if (*flags & MS_RDONLY) {
1510                 /*
1511                  * this also happens on 'umount -rf' or on shutdown, when
1512                  * the filesystem is busy.
1513                  */
1514                 cancel_work_sync(&fs_info->async_reclaim_work);
1515
1516                 /* wait for the uuid_scan task to finish */
1517                 down(&fs_info->uuid_tree_rescan_sem);
1518                 /* avoid complains from lockdep et al. */
1519                 up(&fs_info->uuid_tree_rescan_sem);
1520
1521                 sb->s_flags |= MS_RDONLY;
1522
1523                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1524                 btrfs_scrub_cancel(fs_info);
1525                 btrfs_pause_balance(fs_info);
1526
1527                 ret = btrfs_commit_super(root);
1528                 if (ret)
1529                         goto restore;
1530         } else {
1531                 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1532                         btrfs_err(fs_info,
1533                                 "Remounting read-write after error is not allowed");
1534                         ret = -EINVAL;
1535                         goto restore;
1536                 }
1537                 if (fs_info->fs_devices->rw_devices == 0) {
1538                         ret = -EACCES;
1539                         goto restore;
1540                 }
1541
1542                 if (fs_info->fs_devices->missing_devices >
1543                      fs_info->num_tolerated_disk_barrier_failures &&
1544                     !(*flags & MS_RDONLY)) {
1545                         btrfs_warn(fs_info,
1546                                 "too many missing devices, writeable remount is not allowed");
1547                         ret = -EACCES;
1548                         goto restore;
1549                 }
1550
1551                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1552                         ret = -EINVAL;
1553                         goto restore;
1554                 }
1555
1556                 ret = btrfs_cleanup_fs_roots(fs_info);
1557                 if (ret)
1558                         goto restore;
1559
1560                 /* recover relocation */
1561                 mutex_lock(&fs_info->cleaner_mutex);
1562                 ret = btrfs_recover_relocation(root);
1563                 mutex_unlock(&fs_info->cleaner_mutex);
1564                 if (ret)
1565                         goto restore;
1566
1567                 ret = btrfs_resume_balance_async(fs_info);
1568                 if (ret)
1569                         goto restore;
1570
1571                 ret = btrfs_resume_dev_replace_async(fs_info);
1572                 if (ret) {
1573                         btrfs_warn(fs_info, "failed to resume dev_replace");
1574                         goto restore;
1575                 }
1576
1577                 if (!fs_info->uuid_root) {
1578                         btrfs_info(fs_info, "creating UUID tree");
1579                         ret = btrfs_create_uuid_tree(fs_info);
1580                         if (ret) {
1581                                 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1582                                 goto restore;
1583                         }
1584                 }
1585                 sb->s_flags &= ~MS_RDONLY;
1586         }
1587 out:
1588         wake_up_process(fs_info->transaction_kthread);
1589         btrfs_remount_cleanup(fs_info, old_opts);
1590         return 0;
1591
1592 restore:
1593         /* We've hit an error - don't reset MS_RDONLY */
1594         if (sb->s_flags & MS_RDONLY)
1595                 old_flags |= MS_RDONLY;
1596         sb->s_flags = old_flags;
1597         fs_info->mount_opt = old_opts;
1598         fs_info->compress_type = old_compress_type;
1599         fs_info->max_inline = old_max_inline;
1600         mutex_lock(&fs_info->chunk_mutex);
1601         fs_info->alloc_start = old_alloc_start;
1602         mutex_unlock(&fs_info->chunk_mutex);
1603         btrfs_resize_thread_pool(fs_info,
1604                 old_thread_pool_size, fs_info->thread_pool_size);
1605         fs_info->metadata_ratio = old_metadata_ratio;
1606         btrfs_remount_cleanup(fs_info, old_opts);
1607         return ret;
1608 }
1609
1610 /* Used to sort the devices by max_avail(descending sort) */
1611 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1612                                        const void *dev_info2)
1613 {
1614         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1615             ((struct btrfs_device_info *)dev_info2)->max_avail)
1616                 return -1;
1617         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1618                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1619                 return 1;
1620         else
1621         return 0;
1622 }
1623
1624 /*
1625  * sort the devices by max_avail, in which max free extent size of each device
1626  * is stored.(Descending Sort)
1627  */
1628 static inline void btrfs_descending_sort_devices(
1629                                         struct btrfs_device_info *devices,
1630                                         size_t nr_devices)
1631 {
1632         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1633              btrfs_cmp_device_free_bytes, NULL);
1634 }
1635
1636 /*
1637  * The helper to calc the free space on the devices that can be used to store
1638  * file data.
1639  */
1640 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1641 {
1642         struct btrfs_fs_info *fs_info = root->fs_info;
1643         struct btrfs_device_info *devices_info;
1644         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1645         struct btrfs_device *device;
1646         u64 skip_space;
1647         u64 type;
1648         u64 avail_space;
1649         u64 used_space;
1650         u64 min_stripe_size;
1651         int min_stripes = 1, num_stripes = 1;
1652         int i = 0, nr_devices;
1653         int ret;
1654
1655         /*
1656          * We aren't under the device list lock, so this is racey-ish, but good
1657          * enough for our purposes.
1658          */
1659         nr_devices = fs_info->fs_devices->open_devices;
1660         if (!nr_devices) {
1661                 smp_mb();
1662                 nr_devices = fs_info->fs_devices->open_devices;
1663                 ASSERT(nr_devices);
1664                 if (!nr_devices) {
1665                         *free_bytes = 0;
1666                         return 0;
1667                 }
1668         }
1669
1670         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1671                                GFP_NOFS);
1672         if (!devices_info)
1673                 return -ENOMEM;
1674
1675         /* calc min stripe number for data space alloction */
1676         type = btrfs_get_alloc_profile(root, 1);
1677         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1678                 min_stripes = 2;
1679                 num_stripes = nr_devices;
1680         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1681                 min_stripes = 2;
1682                 num_stripes = 2;
1683         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1684                 min_stripes = 4;
1685                 num_stripes = 4;
1686         }
1687
1688         if (type & BTRFS_BLOCK_GROUP_DUP)
1689                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1690         else
1691                 min_stripe_size = BTRFS_STRIPE_LEN;
1692
1693         if (fs_info->alloc_start)
1694                 mutex_lock(&fs_devices->device_list_mutex);
1695         rcu_read_lock();
1696         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1697                 if (!device->in_fs_metadata || !device->bdev ||
1698                     device->is_tgtdev_for_dev_replace)
1699                         continue;
1700
1701                 if (i >= nr_devices)
1702                         break;
1703
1704                 avail_space = device->total_bytes - device->bytes_used;
1705
1706                 /* align with stripe_len */
1707                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1708                 avail_space *= BTRFS_STRIPE_LEN;
1709
1710                 /*
1711                  * In order to avoid overwritting the superblock on the drive,
1712                  * btrfs starts at an offset of at least 1MB when doing chunk
1713                  * allocation.
1714                  */
1715                 skip_space = 1024 * 1024;
1716
1717                 /* user can set the offset in fs_info->alloc_start. */
1718                 if (fs_info->alloc_start &&
1719                     fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1720                     device->total_bytes) {
1721                         rcu_read_unlock();
1722                         skip_space = max(fs_info->alloc_start, skip_space);
1723
1724                         /*
1725                          * btrfs can not use the free space in
1726                          * [0, skip_space - 1], we must subtract it from the
1727                          * total. In order to implement it, we account the used
1728                          * space in this range first.
1729                          */
1730                         ret = btrfs_account_dev_extents_size(device, 0,
1731                                                              skip_space - 1,
1732                                                              &used_space);
1733                         if (ret) {
1734                                 kfree(devices_info);
1735                                 mutex_unlock(&fs_devices->device_list_mutex);
1736                                 return ret;
1737                         }
1738
1739                         rcu_read_lock();
1740
1741                         /* calc the free space in [0, skip_space - 1] */
1742                         skip_space -= used_space;
1743                 }
1744
1745                 /*
1746                  * we can use the free space in [0, skip_space - 1], subtract
1747                  * it from the total.
1748                  */
1749                 if (avail_space && avail_space >= skip_space)
1750                         avail_space -= skip_space;
1751                 else
1752                         avail_space = 0;
1753
1754                 if (avail_space < min_stripe_size)
1755                         continue;
1756
1757                 devices_info[i].dev = device;
1758                 devices_info[i].max_avail = avail_space;
1759
1760                 i++;
1761         }
1762         rcu_read_unlock();
1763         if (fs_info->alloc_start)
1764                 mutex_unlock(&fs_devices->device_list_mutex);
1765
1766         nr_devices = i;
1767
1768         btrfs_descending_sort_devices(devices_info, nr_devices);
1769
1770         i = nr_devices - 1;
1771         avail_space = 0;
1772         while (nr_devices >= min_stripes) {
1773                 if (num_stripes > nr_devices)
1774                         num_stripes = nr_devices;
1775
1776                 if (devices_info[i].max_avail >= min_stripe_size) {
1777                         int j;
1778                         u64 alloc_size;
1779
1780                         avail_space += devices_info[i].max_avail * num_stripes;
1781                         alloc_size = devices_info[i].max_avail;
1782                         for (j = i + 1 - num_stripes; j <= i; j++)
1783                                 devices_info[j].max_avail -= alloc_size;
1784                 }
1785                 i--;
1786                 nr_devices--;
1787         }
1788
1789         kfree(devices_info);
1790         *free_bytes = avail_space;
1791         return 0;
1792 }
1793
1794 /*
1795  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1796  *
1797  * If there's a redundant raid level at DATA block groups, use the respective
1798  * multiplier to scale the sizes.
1799  *
1800  * Unused device space usage is based on simulating the chunk allocator
1801  * algorithm that respects the device sizes, order of allocations and the
1802  * 'alloc_start' value, this is a close approximation of the actual use but
1803  * there are other factors that may change the result (like a new metadata
1804  * chunk).
1805  *
1806  * FIXME: not accurate for mixed block groups, total and free/used are ok,
1807  * available appears slightly larger.
1808  */
1809 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1810 {
1811         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1812         struct btrfs_super_block *disk_super = fs_info->super_copy;
1813         struct list_head *head = &fs_info->space_info;
1814         struct btrfs_space_info *found;
1815         u64 total_used = 0;
1816         u64 total_free_data = 0;
1817         int bits = dentry->d_sb->s_blocksize_bits;
1818         __be32 *fsid = (__be32 *)fs_info->fsid;
1819         unsigned factor = 1;
1820         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1821         int ret;
1822
1823         /*
1824          * holding chunk_muext to avoid allocating new chunks, holding
1825          * device_list_mutex to avoid the device being removed
1826          */
1827         rcu_read_lock();
1828         list_for_each_entry_rcu(found, head, list) {
1829                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1830                         int i;
1831
1832                         total_free_data += found->disk_total - found->disk_used;
1833                         total_free_data -=
1834                                 btrfs_account_ro_block_groups_free_space(found);
1835
1836                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1837                                 if (!list_empty(&found->block_groups[i])) {
1838                                         switch (i) {
1839                                         case BTRFS_RAID_DUP:
1840                                         case BTRFS_RAID_RAID1:
1841                                         case BTRFS_RAID_RAID10:
1842                                                 factor = 2;
1843                                         }
1844                                 }
1845                         }
1846                 }
1847
1848                 total_used += found->disk_used;
1849         }
1850
1851         rcu_read_unlock();
1852
1853         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
1854         buf->f_blocks >>= bits;
1855         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
1856
1857         /* Account global block reserve as used, it's in logical size already */
1858         spin_lock(&block_rsv->lock);
1859         buf->f_bfree -= block_rsv->size >> bits;
1860         spin_unlock(&block_rsv->lock);
1861
1862         buf->f_bavail = div_u64(total_free_data, factor);
1863         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1864         if (ret)
1865                 return ret;
1866         buf->f_bavail += div_u64(total_free_data, factor);
1867         buf->f_bavail = buf->f_bavail >> bits;
1868
1869         buf->f_type = BTRFS_SUPER_MAGIC;
1870         buf->f_bsize = dentry->d_sb->s_blocksize;
1871         buf->f_namelen = BTRFS_NAME_LEN;
1872
1873         /* We treat it as constant endianness (it doesn't matter _which_)
1874            because we want the fsid to come out the same whether mounted
1875            on a big-endian or little-endian host */
1876         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1877         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1878         /* Mask in the root object ID too, to disambiguate subvols */
1879         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
1880         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
1881
1882         return 0;
1883 }
1884
1885 static void btrfs_kill_super(struct super_block *sb)
1886 {
1887         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1888         kill_anon_super(sb);
1889         free_fs_info(fs_info);
1890 }
1891
1892 static struct file_system_type btrfs_fs_type = {
1893         .owner          = THIS_MODULE,
1894         .name           = "btrfs",
1895         .mount          = btrfs_mount,
1896         .kill_sb        = btrfs_kill_super,
1897         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
1898 };
1899 MODULE_ALIAS_FS("btrfs");
1900
1901 static int btrfs_control_open(struct inode *inode, struct file *file)
1902 {
1903         /*
1904          * The control file's private_data is used to hold the
1905          * transaction when it is started and is used to keep
1906          * track of whether a transaction is already in progress.
1907          */
1908         file->private_data = NULL;
1909         return 0;
1910 }
1911
1912 /*
1913  * used by btrfsctl to scan devices when no FS is mounted
1914  */
1915 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1916                                 unsigned long arg)
1917 {
1918         struct btrfs_ioctl_vol_args *vol;
1919         struct btrfs_fs_devices *fs_devices;
1920         int ret = -ENOTTY;
1921
1922         if (!capable(CAP_SYS_ADMIN))
1923                 return -EPERM;
1924
1925         vol = memdup_user((void __user *)arg, sizeof(*vol));
1926         if (IS_ERR(vol))
1927                 return PTR_ERR(vol);
1928
1929         switch (cmd) {
1930         case BTRFS_IOC_SCAN_DEV:
1931                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1932                                             &btrfs_fs_type, &fs_devices);
1933                 break;
1934         case BTRFS_IOC_DEVICES_READY:
1935                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1936                                             &btrfs_fs_type, &fs_devices);
1937                 if (ret)
1938                         break;
1939                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
1940                 break;
1941         }
1942
1943         kfree(vol);
1944         return ret;
1945 }
1946
1947 static int btrfs_freeze(struct super_block *sb)
1948 {
1949         struct btrfs_trans_handle *trans;
1950         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
1951
1952         trans = btrfs_attach_transaction_barrier(root);
1953         if (IS_ERR(trans)) {
1954                 /* no transaction, don't bother */
1955                 if (PTR_ERR(trans) == -ENOENT)
1956                         return 0;
1957                 return PTR_ERR(trans);
1958         }
1959         return btrfs_commit_transaction(trans, root);
1960 }
1961
1962 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
1963 {
1964         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
1965         struct btrfs_fs_devices *cur_devices;
1966         struct btrfs_device *dev, *first_dev = NULL;
1967         struct list_head *head;
1968         struct rcu_string *name;
1969
1970         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1971         cur_devices = fs_info->fs_devices;
1972         while (cur_devices) {
1973                 head = &cur_devices->devices;
1974                 list_for_each_entry(dev, head, dev_list) {
1975                         if (dev->missing)
1976                                 continue;
1977                         if (!dev->name)
1978                                 continue;
1979                         if (!first_dev || dev->devid < first_dev->devid)
1980                                 first_dev = dev;
1981                 }
1982                 cur_devices = cur_devices->seed;
1983         }
1984
1985         if (first_dev) {
1986                 rcu_read_lock();
1987                 name = rcu_dereference(first_dev->name);
1988                 seq_escape(m, name->str, " \t\n\\");
1989                 rcu_read_unlock();
1990         } else {
1991                 WARN_ON(1);
1992         }
1993         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1994         return 0;
1995 }
1996
1997 static const struct super_operations btrfs_super_ops = {
1998         .drop_inode     = btrfs_drop_inode,
1999         .evict_inode    = btrfs_evict_inode,
2000         .put_super      = btrfs_put_super,
2001         .sync_fs        = btrfs_sync_fs,
2002         .show_options   = btrfs_show_options,
2003         .show_devname   = btrfs_show_devname,
2004         .write_inode    = btrfs_write_inode,
2005         .alloc_inode    = btrfs_alloc_inode,
2006         .destroy_inode  = btrfs_destroy_inode,
2007         .statfs         = btrfs_statfs,
2008         .remount_fs     = btrfs_remount,
2009         .freeze_fs      = btrfs_freeze,
2010 };
2011
2012 static const struct file_operations btrfs_ctl_fops = {
2013         .open = btrfs_control_open,
2014         .unlocked_ioctl  = btrfs_control_ioctl,
2015         .compat_ioctl = btrfs_control_ioctl,
2016         .owner   = THIS_MODULE,
2017         .llseek = noop_llseek,
2018 };
2019
2020 static struct miscdevice btrfs_misc = {
2021         .minor          = BTRFS_MINOR,
2022         .name           = "btrfs-control",
2023         .fops           = &btrfs_ctl_fops
2024 };
2025
2026 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2027 MODULE_ALIAS("devname:btrfs-control");
2028
2029 static int btrfs_interface_init(void)
2030 {
2031         return misc_register(&btrfs_misc);
2032 }
2033
2034 static void btrfs_interface_exit(void)
2035 {
2036         if (misc_deregister(&btrfs_misc) < 0)
2037                 printk(KERN_INFO "BTRFS: misc_deregister failed for control device\n");
2038 }
2039
2040 static void btrfs_print_info(void)
2041 {
2042         printk(KERN_INFO "Btrfs loaded"
2043 #ifdef CONFIG_BTRFS_DEBUG
2044                         ", debug=on"
2045 #endif
2046 #ifdef CONFIG_BTRFS_ASSERT
2047                         ", assert=on"
2048 #endif
2049 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2050                         ", integrity-checker=on"
2051 #endif
2052                         "\n");
2053 }
2054
2055 static int btrfs_run_sanity_tests(void)
2056 {
2057         int ret;
2058
2059         ret = btrfs_init_test_fs();
2060         if (ret)
2061                 return ret;
2062
2063         ret = btrfs_test_free_space_cache();
2064         if (ret)
2065                 goto out;
2066         ret = btrfs_test_extent_buffer_operations();
2067         if (ret)
2068                 goto out;
2069         ret = btrfs_test_extent_io();
2070         if (ret)
2071                 goto out;
2072         ret = btrfs_test_inodes();
2073         if (ret)
2074                 goto out;
2075         ret = btrfs_test_qgroups();
2076 out:
2077         btrfs_destroy_test_fs();
2078         return ret;
2079 }
2080
2081 static int __init init_btrfs_fs(void)
2082 {
2083         int err;
2084
2085         err = btrfs_hash_init();
2086         if (err)
2087                 return err;
2088
2089         btrfs_props_init();
2090
2091         err = btrfs_init_sysfs();
2092         if (err)
2093                 goto free_hash;
2094
2095         btrfs_init_compress();
2096
2097         err = btrfs_init_cachep();
2098         if (err)
2099                 goto free_compress;
2100
2101         err = extent_io_init();
2102         if (err)
2103                 goto free_cachep;
2104
2105         err = extent_map_init();
2106         if (err)
2107                 goto free_extent_io;
2108
2109         err = ordered_data_init();
2110         if (err)
2111                 goto free_extent_map;
2112
2113         err = btrfs_delayed_inode_init();
2114         if (err)
2115                 goto free_ordered_data;
2116
2117         err = btrfs_auto_defrag_init();
2118         if (err)
2119                 goto free_delayed_inode;
2120
2121         err = btrfs_delayed_ref_init();
2122         if (err)
2123                 goto free_auto_defrag;
2124
2125         err = btrfs_prelim_ref_init();
2126         if (err)
2127                 goto free_delayed_ref;
2128
2129         err = btrfs_end_io_wq_init();
2130         if (err)
2131                 goto free_prelim_ref;
2132
2133         err = btrfs_interface_init();
2134         if (err)
2135                 goto free_end_io_wq;
2136
2137         btrfs_init_lockdep();
2138
2139         btrfs_print_info();
2140
2141         err = btrfs_run_sanity_tests();
2142         if (err)
2143                 goto unregister_ioctl;
2144
2145         err = register_filesystem(&btrfs_fs_type);
2146         if (err)
2147                 goto unregister_ioctl;
2148
2149         return 0;
2150
2151 unregister_ioctl:
2152         btrfs_interface_exit();
2153 free_end_io_wq:
2154         btrfs_end_io_wq_exit();
2155 free_prelim_ref:
2156         btrfs_prelim_ref_exit();
2157 free_delayed_ref:
2158         btrfs_delayed_ref_exit();
2159 free_auto_defrag:
2160         btrfs_auto_defrag_exit();
2161 free_delayed_inode:
2162         btrfs_delayed_inode_exit();
2163 free_ordered_data:
2164         ordered_data_exit();
2165 free_extent_map:
2166         extent_map_exit();
2167 free_extent_io:
2168         extent_io_exit();
2169 free_cachep:
2170         btrfs_destroy_cachep();
2171 free_compress:
2172         btrfs_exit_compress();
2173         btrfs_exit_sysfs();
2174 free_hash:
2175         btrfs_hash_exit();
2176         return err;
2177 }
2178
2179 static void __exit exit_btrfs_fs(void)
2180 {
2181         btrfs_destroy_cachep();
2182         btrfs_delayed_ref_exit();
2183         btrfs_auto_defrag_exit();
2184         btrfs_delayed_inode_exit();
2185         btrfs_prelim_ref_exit();
2186         ordered_data_exit();
2187         extent_map_exit();
2188         extent_io_exit();
2189         btrfs_interface_exit();
2190         btrfs_end_io_wq_exit();
2191         unregister_filesystem(&btrfs_fs_type);
2192         btrfs_exit_sysfs();
2193         btrfs_cleanup_fs_uuids();
2194         btrfs_exit_compress();
2195         btrfs_hash_exit();
2196 }
2197
2198 late_initcall(init_btrfs_fs);
2199 module_exit(exit_btrfs_fs)
2200
2201 MODULE_LICENSE("GPL");