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