kernel/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         if (!(sb->s_flags & MS_RDONLY)) {
 905                 int ret;
 906                 down_read(&fs_info->cleanup_work_sem);
 907                 ret = btrfs_orphan_cleanup(new_root);
 908                 up_read(&fs_info->cleanup_work_sem);
 909                 if (ret)
 910                         return ERR_PTR(ret);
 911         }
 912
 913         dir_id = btrfs_root_dirid(&new_root->root_item);
 914 setup_root:
 915         location.objectid = dir_id;
 916         location.type = BTRFS_INODE_ITEM_KEY;
 917         location.offset = 0;
 918
 919         inode = btrfs_iget(sb, &location, new_root, &new);
 920         if (IS_ERR(inode))
 921                 return ERR_CAST(inode);
 922
 923         /*
 924          * If we're just mounting the root most subvol put the inode and return
 925          * a reference to the dentry.  We will have already gotten a reference
 926          * to the inode in btrfs_fill_super so we're good to go.
 927          */
 928         if (!new && d_inode(sb->s_root) == inode) {
 929                 iput(inode);
 930                 return dget(sb->s_root);
 931         }
 932
 933         return d_obtain_root(inode);
 934 }
 935
 936 static int btrfs_fill_super(struct super_block *sb,
 937                             struct btrfs_fs_devices *fs_devices,
 938                             void *data, int silent)
 939 {
 940         struct inode *inode;
 941         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 942         struct btrfs_key key;
 943         int err;
 944
 945         sb->s_maxbytes = MAX_LFS_FILESIZE;
 946         sb->s_magic = BTRFS_SUPER_MAGIC;
 947         sb->s_op = &btrfs_super_ops;
 948         sb->s_d_op = &btrfs_dentry_operations;
 949         sb->s_export_op = &btrfs_export_ops;
 950         sb->s_xattr = btrfs_xattr_handlers;
 951         sb->s_time_gran = 1;
 952 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 953         sb->s_flags |= MS_POSIXACL;
 954 #endif
 955         sb->s_flags |= MS_I_VERSION;
 956         err = open_ctree(sb, fs_devices, (char *)data);
 957         if (err) {
 958                 printk(KERN_ERR "BTRFS: open_ctree failed\n");
 959                 return err;
 960         }
 961
 962         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 963         key.type = BTRFS_INODE_ITEM_KEY;
 964         key.offset = 0;
 965         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
 966         if (IS_ERR(inode)) {
 967                 err = PTR_ERR(inode);
 968                 goto fail_close;
 969         }
 970
 971         sb->s_root = d_make_root(inode);
 972         if (!sb->s_root) {
 973                 err = -ENOMEM;
 974                 goto fail_close;
 975         }
 976
 977         save_mount_options(sb, data);
 978         cleancache_init_fs(sb);
 979         sb->s_flags |= MS_ACTIVE;
 980         return 0;
 981
 982 fail_close:
 983         close_ctree(fs_info->tree_root);
 984         return err;
 985 }
 986
 987 int btrfs_sync_fs(struct super_block *sb, int wait)
 988 {
 989         struct btrfs_trans_handle *trans;
 990         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 991         struct btrfs_root *root = fs_info->tree_root;
 992
 993         trace_btrfs_sync_fs(wait);
 994
 995         if (!wait) {
 996                 filemap_flush(fs_info->btree_inode->i_mapping);
 997                 return 0;
 998         }
 999
1000         btrfs_wait_ordered_roots(fs_info, -1);
1001
1002         trans = btrfs_attach_transaction_barrier(root);
1003         if (IS_ERR(trans)) {
1004                 /* no transaction, don't bother */
1005                 if (PTR_ERR(trans) == -ENOENT) {
1006                         /*
1007                          * Exit unless we have some pending changes
1008                          * that need to go through commit
1009                          */
1010                         if (fs_info->pending_changes == 0)
1011                                 return 0;
1012                         /*
1013                          * A non-blocking test if the fs is frozen. We must not
1014                          * start a new transaction here otherwise a deadlock
1015                          * happens. The pending operations are delayed to the
1016                          * next commit after thawing.
1017                          */
1018                         if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1019                                 __sb_end_write(sb, SB_FREEZE_WRITE);
1020                         else
1021                                 return 0;
1022                         trans = btrfs_start_transaction(root, 0);
1023                 }
1024                 if (IS_ERR(trans))
1025                         return PTR_ERR(trans);
1026         }
1027         return btrfs_commit_transaction(trans, root);
1028 }
1029
1030 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1031 {
1032         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1033         struct btrfs_root *root = info->tree_root;
1034         char *compress_type;
1035
1036         if (btrfs_test_opt(root, DEGRADED))
1037                 seq_puts(seq, ",degraded");
1038         if (btrfs_test_opt(root, NODATASUM))
1039                 seq_puts(seq, ",nodatasum");
1040         if (btrfs_test_opt(root, NODATACOW))
1041                 seq_puts(seq, ",nodatacow");
1042         if (btrfs_test_opt(root, NOBARRIER))
1043                 seq_puts(seq, ",nobarrier");
1044         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1045                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1046         if (info->alloc_start != 0)
1047                 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1048         if (info->thread_pool_size !=  min_t(unsigned long,
1049                                              num_online_cpus() + 2, 8))
1050                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1051         if (btrfs_test_opt(root, COMPRESS)) {
1052                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1053                         compress_type = "zlib";
1054                 else
1055                         compress_type = "lzo";
1056                 if (btrfs_test_opt(root, FORCE_COMPRESS))
1057                         seq_printf(seq, ",compress-force=%s", compress_type);
1058                 else
1059                         seq_printf(seq, ",compress=%s", compress_type);
1060         }
1061         if (btrfs_test_opt(root, NOSSD))
1062                 seq_puts(seq, ",nossd");
1063         if (btrfs_test_opt(root, SSD_SPREAD))
1064                 seq_puts(seq, ",ssd_spread");
1065         else if (btrfs_test_opt(root, SSD))
1066                 seq_puts(seq, ",ssd");
1067         if (btrfs_test_opt(root, NOTREELOG))
1068                 seq_puts(seq, ",notreelog");
1069         if (btrfs_test_opt(root, FLUSHONCOMMIT))
1070                 seq_puts(seq, ",flushoncommit");
1071         if (btrfs_test_opt(root, DISCARD))
1072                 seq_puts(seq, ",discard");
1073         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1074                 seq_puts(seq, ",noacl");
1075         if (btrfs_test_opt(root, SPACE_CACHE))
1076                 seq_puts(seq, ",space_cache");
1077         else
1078                 seq_puts(seq, ",nospace_cache");
1079         if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1080                 seq_puts(seq, ",rescan_uuid_tree");
1081         if (btrfs_test_opt(root, CLEAR_CACHE))
1082                 seq_puts(seq, ",clear_cache");
1083         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1084                 seq_puts(seq, ",user_subvol_rm_allowed");
1085         if (btrfs_test_opt(root, ENOSPC_DEBUG))
1086                 seq_puts(seq, ",enospc_debug");
1087         if (btrfs_test_opt(root, AUTO_DEFRAG))
1088                 seq_puts(seq, ",autodefrag");
1089         if (btrfs_test_opt(root, INODE_MAP_CACHE))
1090                 seq_puts(seq, ",inode_cache");
1091         if (btrfs_test_opt(root, SKIP_BALANCE))
1092                 seq_puts(seq, ",skip_balance");
1093         if (btrfs_test_opt(root, RECOVERY))
1094                 seq_puts(seq, ",recovery");
1095 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1096         if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1097                 seq_puts(seq, ",check_int_data");
1098         else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1099                 seq_puts(seq, ",check_int");
1100         if (info->check_integrity_print_mask)
1101                 seq_printf(seq, ",check_int_print_mask=%d",
1102                                 info->check_integrity_print_mask);
1103 #endif
1104         if (info->metadata_ratio)
1105                 seq_printf(seq, ",metadata_ratio=%d",
1106                                 info->metadata_ratio);
1107         if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1108                 seq_puts(seq, ",fatal_errors=panic");
1109         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1110                 seq_printf(seq, ",commit=%d", info->commit_interval);
1111         return 0;
1112 }
1113
1114 static int btrfs_test_super(struct super_block *s, void *data)
1115 {
1116         struct btrfs_fs_info *p = data;
1117         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1118
1119         return fs_info->fs_devices == p->fs_devices;
1120 }
1121
1122 static int btrfs_set_super(struct super_block *s, void *data)
1123 {
1124         int err = set_anon_super(s, data);
1125         if (!err)
1126                 s->s_fs_info = data;
1127         return err;
1128 }
1129
1130 /*
1131  * subvolumes are identified by ino 256
1132  */
1133 static inline int is_subvolume_inode(struct inode *inode)
1134 {
1135         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1136                 return 1;
1137         return 0;
1138 }
1139
1140 /*
1141  * This will strip out the subvol=%s argument for an argument string and add
1142  * subvolid=0 to make sure we get the actual tree root for path walking to the
1143  * subvol we want.
1144  */
1145 static char *setup_root_args(char *args)
1146 {
1147         unsigned len = strlen(args) + 2 + 1;
1148         char *src, *dst, *buf;
1149
1150         /*
1151          * We need the same args as before, but with this substitution:
1152          * s!subvol=[^,]+!subvolid=0!
1153          *
1154          * Since the replacement string is up to 2 bytes longer than the
1155          * original, allocate strlen(args) + 2 + 1 bytes.
1156          */
1157
1158         src = strstr(args, "subvol=");
1159         /* This shouldn't happen, but just in case.. */
1160         if (!src)
1161                 return NULL;
1162
1163         buf = dst = kmalloc(len, GFP_NOFS);
1164         if (!buf)
1165                 return NULL;
1166
1167         /*
1168          * If the subvol= arg is not at the start of the string,
1169          * copy whatever precedes it into buf.
1170          */
1171         if (src != args) {
1172                 *src++ = '\0';
1173                 strcpy(buf, args);
1174                 dst += strlen(args);
1175         }
1176
1177         strcpy(dst, "subvolid=0");
1178         dst += strlen("subvolid=0");
1179
1180         /*
1181          * If there is a "," after the original subvol=... string,
1182          * copy that suffix into our buffer.  Otherwise, we're done.
1183          */
1184         src = strchr(src, ',');
1185         if (src)
1186                 strcpy(dst, src);
1187
1188         return buf;
1189 }
1190
1191 static struct dentry *mount_subvol(const char *subvol_name, int flags,
1192                                    const char *device_name, char *data)
1193 {
1194         struct dentry *root;
1195         struct vfsmount *mnt;
1196         char *newargs;
1197
1198         newargs = setup_root_args(data);
1199         if (!newargs)
1200                 return ERR_PTR(-ENOMEM);
1201         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
1202                              newargs);
1203
1204         if (PTR_RET(mnt) == -EBUSY) {
1205                 if (flags & MS_RDONLY) {
1206                         mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY, device_name,
1207                                              newargs);
1208                 } else {
1209                         int r;
1210                         mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY, device_name,
1211                                              newargs);
1212                         if (IS_ERR(mnt)) {
1213                                 kfree(newargs);
1214                                 return ERR_CAST(mnt);
1215                         }
1216
1217                         r = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1218                         if (r < 0) {
1219                                 /* FIXME: release vfsmount mnt ??*/
1220                                 kfree(newargs);
1221                                 return ERR_PTR(r);
1222                         }
1223                 }
1224         }
1225
1226         kfree(newargs);
1227
1228         if (IS_ERR(mnt))
1229                 return ERR_CAST(mnt);
1230
1231         root = mount_subtree(mnt, subvol_name);
1232
1233         if (!IS_ERR(root) && !is_subvolume_inode(d_inode(root))) {
1234                 struct super_block *s = root->d_sb;
1235                 dput(root);
1236                 root = ERR_PTR(-EINVAL);
1237                 deactivate_locked_super(s);
1238                 printk(KERN_ERR "BTRFS: '%s' is not a valid subvolume\n",
1239                                 subvol_name);
1240         }
1241
1242         return root;
1243 }
1244
1245 static int parse_security_options(char *orig_opts,
1246                                   struct security_mnt_opts *sec_opts)
1247 {
1248         char *secdata = NULL;
1249         int ret = 0;
1250
1251         secdata = alloc_secdata();
1252         if (!secdata)
1253                 return -ENOMEM;
1254         ret = security_sb_copy_data(orig_opts, secdata);
1255         if (ret) {
1256                 free_secdata(secdata);
1257                 return ret;
1258         }
1259         ret = security_sb_parse_opts_str(secdata, sec_opts);
1260         free_secdata(secdata);
1261         return ret;
1262 }
1263
1264 static int setup_security_options(struct btrfs_fs_info *fs_info,
1265                                   struct super_block *sb,
1266                                   struct security_mnt_opts *sec_opts)
1267 {
1268         int ret = 0;
1269
1270         /*
1271          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1272          * is valid.
1273          */
1274         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1275         if (ret)
1276                 return ret;
1277
1278 #ifdef CONFIG_SECURITY
1279         if (!fs_info->security_opts.num_mnt_opts) {
1280                 /* first time security setup, copy sec_opts to fs_info */
1281                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1282         } else {
1283                 /*
1284                  * Since SELinux(the only one supports security_mnt_opts) does
1285                  * NOT support changing context during remount/mount same sb,
1286                  * This must be the same or part of the same security options,
1287                  * just free it.
1288                  */
1289                 security_free_mnt_opts(sec_opts);
1290         }
1291 #endif
1292         return ret;
1293 }
1294
1295 /*
1296  * Find a superblock for the given device / mount point.
1297  *
1298  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1299  *        for multiple device setup.  Make sure to keep it in sync.
1300  */
1301 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1302                 const char *device_name, void *data)
1303 {
1304         struct block_device *bdev = NULL;
1305         struct super_block *s;
1306         struct dentry *root;
1307         struct btrfs_fs_devices *fs_devices = NULL;
1308         struct btrfs_fs_info *fs_info = NULL;
1309         struct security_mnt_opts new_sec_opts;
1310         fmode_t mode = FMODE_READ;
1311         char *subvol_name = NULL;
1312         u64 subvol_objectid = 0;
1313         int error = 0;
1314
1315         if (!(flags & MS_RDONLY))
1316                 mode |= FMODE_WRITE;
1317
1318         error = btrfs_parse_early_options(data, mode, fs_type,
1319                                           &subvol_name, &subvol_objectid,
1320                                           &fs_devices);
1321         if (error) {
1322                 kfree(subvol_name);
1323                 return ERR_PTR(error);
1324         }
1325
1326         if (subvol_name) {
1327                 root = mount_subvol(subvol_name, flags, device_name, data);
1328                 kfree(subvol_name);
1329                 return root;
1330         }
1331
1332         security_init_mnt_opts(&new_sec_opts);
1333         if (data) {
1334                 error = parse_security_options(data, &new_sec_opts);
1335                 if (error)
1336                         return ERR_PTR(error);
1337         }
1338
1339         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1340         if (error)
1341                 goto error_sec_opts;
1342
1343         /*
1344          * Setup a dummy root and fs_info for test/set super.  This is because
1345          * we don't actually fill this stuff out until open_ctree, but we need
1346          * it for searching for existing supers, so this lets us do that and
1347          * then open_ctree will properly initialize everything later.
1348          */
1349         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1350         if (!fs_info) {
1351                 error = -ENOMEM;
1352                 goto error_sec_opts;
1353         }
1354
1355         fs_info->fs_devices = fs_devices;
1356
1357         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1358         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1359         security_init_mnt_opts(&fs_info->security_opts);
1360         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1361                 error = -ENOMEM;
1362                 goto error_fs_info;
1363         }
1364
1365         error = btrfs_open_devices(fs_devices, mode, fs_type);
1366         if (error)
1367                 goto error_fs_info;
1368
1369         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1370                 error = -EACCES;
1371                 goto error_close_devices;
1372         }
1373
1374         bdev = fs_devices->latest_bdev;
1375         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1376                  fs_info);
1377         if (IS_ERR(s)) {
1378                 error = PTR_ERR(s);
1379                 goto error_close_devices;
1380         }
1381
1382         if (s->s_root) {
1383                 btrfs_close_devices(fs_devices);
1384                 free_fs_info(fs_info);
1385                 if ((flags ^ s->s_flags) & MS_RDONLY)
1386                         error = -EBUSY;
1387         } else {
1388                 char b[BDEVNAME_SIZE];
1389
1390                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1391                 btrfs_sb(s)->bdev_holder = fs_type;
1392                 error = btrfs_fill_super(s, fs_devices, data,
1393                                          flags & MS_SILENT ? 1 : 0);
1394         }
1395
1396         root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
1397         if (IS_ERR(root)) {
1398                 deactivate_locked_super(s);
1399                 error = PTR_ERR(root);
1400                 goto error_sec_opts;
1401         }
1402
1403         fs_info = btrfs_sb(s);
1404         error = setup_security_options(fs_info, s, &new_sec_opts);
1405         if (error) {
1406                 dput(root);
1407                 deactivate_locked_super(s);
1408                 goto error_sec_opts;
1409         }
1410
1411         return root;
1412
1413 error_close_devices:
1414         btrfs_close_devices(fs_devices);
1415 error_fs_info:
1416         free_fs_info(fs_info);
1417 error_sec_opts:
1418         security_free_mnt_opts(&new_sec_opts);
1419         return ERR_PTR(error);
1420 }
1421
1422 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1423                                      int new_pool_size, int old_pool_size)
1424 {
1425         if (new_pool_size == old_pool_size)
1426                 return;
1427
1428         fs_info->thread_pool_size = new_pool_size;
1429
1430         btrfs_info(fs_info, "resize thread pool %d -> %d",
1431                old_pool_size, new_pool_size);
1432
1433         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1434         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1435         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1436         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1437         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1438         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1439         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1440                                 new_pool_size);
1441         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1442         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1443         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1444         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1445         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1446                                 new_pool_size);
1447 }
1448
1449 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1450 {
1451         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1452 }
1453
1454 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1455                                        unsigned long old_opts, int flags)
1456 {
1457         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1458             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1459              (flags & MS_RDONLY))) {
1460                 /* wait for any defraggers to finish */
1461                 wait_event(fs_info->transaction_wait,
1462                            (atomic_read(&fs_info->defrag_running) == 0));
1463                 if (flags & MS_RDONLY)
1464                         sync_filesystem(fs_info->sb);
1465         }
1466 }
1467
1468 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1469                                          unsigned long old_opts)
1470 {
1471         /*
1472          * We need cleanup all defragable inodes if the autodefragment is
1473          * close or the fs is R/O.
1474          */
1475         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1476             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1477              (fs_info->sb->s_flags & MS_RDONLY))) {
1478                 btrfs_cleanup_defrag_inodes(fs_info);
1479         }
1480
1481         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1482 }
1483
1484 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1485 {
1486         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1487         struct btrfs_root *root = fs_info->tree_root;
1488         unsigned old_flags = sb->s_flags;
1489         unsigned long old_opts = fs_info->mount_opt;
1490         unsigned long old_compress_type = fs_info->compress_type;
1491         u64 old_max_inline = fs_info->max_inline;
1492         u64 old_alloc_start = fs_info->alloc_start;
1493         int old_thread_pool_size = fs_info->thread_pool_size;
1494         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1495         int ret;
1496
1497         sync_filesystem(sb);
1498         btrfs_remount_prepare(fs_info);
1499
1500         if (data) {
1501                 struct security_mnt_opts new_sec_opts;
1502
1503                 security_init_mnt_opts(&new_sec_opts);
1504                 ret = parse_security_options(data, &new_sec_opts);
1505                 if (ret)
1506                         goto restore;
1507                 ret = setup_security_options(fs_info, sb,
1508                                              &new_sec_opts);
1509                 if (ret) {
1510                         security_free_mnt_opts(&new_sec_opts);
1511                         goto restore;
1512                 }
1513         }
1514
1515         ret = btrfs_parse_options(root, data);
1516         if (ret) {
1517                 ret = -EINVAL;
1518                 goto restore;
1519         }
1520
1521         btrfs_remount_begin(fs_info, old_opts, *flags);
1522         btrfs_resize_thread_pool(fs_info,
1523                 fs_info->thread_pool_size, old_thread_pool_size);
1524
1525         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1526                 goto out;
1527
1528         if (*flags & MS_RDONLY) {
1529                 /*
1530                  * this also happens on 'umount -rf' or on shutdown, when
1531                  * the filesystem is busy.
1532                  */
1533                 cancel_work_sync(&fs_info->async_reclaim_work);
1534
1535                 /* wait for the uuid_scan task to finish */
1536                 down(&fs_info->uuid_tree_rescan_sem);
1537                 /* avoid complains from lockdep et al. */
1538                 up(&fs_info->uuid_tree_rescan_sem);
1539
1540                 sb->s_flags |= MS_RDONLY;
1541
1542                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1543                 btrfs_scrub_cancel(fs_info);
1544                 btrfs_pause_balance(fs_info);
1545
1546                 ret = btrfs_commit_super(root);
1547                 if (ret)
1548                         goto restore;
1549         } else {
1550                 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1551                         btrfs_err(fs_info,
1552                                 "Remounting read-write after error is not allowed");
1553                         ret = -EINVAL;
1554                         goto restore;
1555                 }
1556                 if (fs_info->fs_devices->rw_devices == 0) {
1557                         ret = -EACCES;
1558                         goto restore;
1559                 }
1560
1561                 if (fs_info->fs_devices->missing_devices >
1562                      fs_info->num_tolerated_disk_barrier_failures &&
1563                     !(*flags & MS_RDONLY)) {
1564                         btrfs_warn(fs_info,
1565                                 "too many missing devices, writeable remount is not allowed");
1566                         ret = -EACCES;
1567                         goto restore;
1568                 }
1569
1570                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1571                         ret = -EINVAL;
1572                         goto restore;
1573                 }
1574
1575                 ret = btrfs_cleanup_fs_roots(fs_info);
1576                 if (ret)
1577                         goto restore;
1578
1579                 /* recover relocation */
1580                 mutex_lock(&fs_info->cleaner_mutex);
1581                 ret = btrfs_recover_relocation(root);
1582                 mutex_unlock(&fs_info->cleaner_mutex);
1583                 if (ret)
1584                         goto restore;
1585
1586                 ret = btrfs_resume_balance_async(fs_info);
1587                 if (ret)
1588                         goto restore;
1589
1590                 ret = btrfs_resume_dev_replace_async(fs_info);
1591                 if (ret) {
1592                         btrfs_warn(fs_info, "failed to resume dev_replace");
1593                         goto restore;
1594                 }
1595
1596                 if (!fs_info->uuid_root) {
1597                         btrfs_info(fs_info, "creating UUID tree");
1598                         ret = btrfs_create_uuid_tree(fs_info);
1599                         if (ret) {
1600                                 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1601                                 goto restore;
1602                         }
1603                 }
1604                 sb->s_flags &= ~MS_RDONLY;
1605         }
1606 out:
1607         wake_up_process(fs_info->transaction_kthread);
1608         btrfs_remount_cleanup(fs_info, old_opts);
1609         return 0;
1610
1611 restore:
1612         /* We've hit an error - don't reset MS_RDONLY */
1613         if (sb->s_flags & MS_RDONLY)
1614                 old_flags |= MS_RDONLY;
1615         sb->s_flags = old_flags;
1616         fs_info->mount_opt = old_opts;
1617         fs_info->compress_type = old_compress_type;
1618         fs_info->max_inline = old_max_inline;
1619         mutex_lock(&fs_info->chunk_mutex);
1620         fs_info->alloc_start = old_alloc_start;
1621         mutex_unlock(&fs_info->chunk_mutex);
1622         btrfs_resize_thread_pool(fs_info,
1623                 old_thread_pool_size, fs_info->thread_pool_size);
1624         fs_info->metadata_ratio = old_metadata_ratio;
1625         btrfs_remount_cleanup(fs_info, old_opts);
1626         return ret;
1627 }
1628
1629 /* Used to sort the devices by max_avail(descending sort) */
1630 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1631                                        const void *dev_info2)
1632 {
1633         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1634             ((struct btrfs_device_info *)dev_info2)->max_avail)
1635                 return -1;
1636         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1637                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1638                 return 1;
1639         else
1640         return 0;
1641 }
1642
1643 /*
1644  * sort the devices by max_avail, in which max free extent size of each device
1645  * is stored.(Descending Sort)
1646  */
1647 static inline void btrfs_descending_sort_devices(
1648                                         struct btrfs_device_info *devices,
1649                                         size_t nr_devices)
1650 {
1651         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1652              btrfs_cmp_device_free_bytes, NULL);
1653 }
1654
1655 /*
1656  * The helper to calc the free space on the devices that can be used to store
1657  * file data.
1658  */
1659 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1660 {
1661         struct btrfs_fs_info *fs_info = root->fs_info;
1662         struct btrfs_device_info *devices_info;
1663         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1664         struct btrfs_device *device;
1665         u64 skip_space;
1666         u64 type;
1667         u64 avail_space;
1668         u64 used_space;
1669         u64 min_stripe_size;
1670         int min_stripes = 1, num_stripes = 1;
1671         int i = 0, nr_devices;
1672         int ret;
1673
1674         /*
1675          * We aren't under the device list lock, so this is racey-ish, but good
1676          * enough for our purposes.
1677          */
1678         nr_devices = fs_info->fs_devices->open_devices;
1679         if (!nr_devices) {
1680                 smp_mb();
1681                 nr_devices = fs_info->fs_devices->open_devices;
1682                 ASSERT(nr_devices);
1683                 if (!nr_devices) {
1684                         *free_bytes = 0;
1685                         return 0;
1686                 }
1687         }
1688
1689         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1690                                GFP_NOFS);
1691         if (!devices_info)
1692                 return -ENOMEM;
1693
1694         /* calc min stripe number for data space alloction */
1695         type = btrfs_get_alloc_profile(root, 1);
1696         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1697                 min_stripes = 2;
1698                 num_stripes = nr_devices;
1699         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1700                 min_stripes = 2;
1701                 num_stripes = 2;
1702         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1703                 min_stripes = 4;
1704                 num_stripes = 4;
1705         }
1706
1707         if (type & BTRFS_BLOCK_GROUP_DUP)
1708                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1709         else
1710                 min_stripe_size = BTRFS_STRIPE_LEN;
1711
1712         if (fs_info->alloc_start)
1713                 mutex_lock(&fs_devices->device_list_mutex);
1714         rcu_read_lock();
1715         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1716                 if (!device->in_fs_metadata || !device->bdev ||
1717                     device->is_tgtdev_for_dev_replace)
1718                         continue;
1719
1720                 if (i >= nr_devices)
1721                         break;
1722
1723                 avail_space = device->total_bytes - device->bytes_used;
1724
1725                 /* align with stripe_len */
1726                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1727                 avail_space *= BTRFS_STRIPE_LEN;
1728
1729                 /*
1730                  * In order to avoid overwritting the superblock on the drive,
1731                  * btrfs starts at an offset of at least 1MB when doing chunk
1732                  * allocation.
1733                  */
1734                 skip_space = 1024 * 1024;
1735
1736                 /* user can set the offset in fs_info->alloc_start. */
1737                 if (fs_info->alloc_start &&
1738                     fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1739                     device->total_bytes) {
1740                         rcu_read_unlock();
1741                         skip_space = max(fs_info->alloc_start, skip_space);
1742
1743                         /*
1744                          * btrfs can not use the free space in
1745                          * [0, skip_space - 1], we must subtract it from the
1746                          * total. In order to implement it, we account the used
1747                          * space in this range first.
1748                          */
1749                         ret = btrfs_account_dev_extents_size(device, 0,
1750                                                              skip_space - 1,
1751                                                              &used_space);
1752                         if (ret) {
1753                                 kfree(devices_info);
1754                                 mutex_unlock(&fs_devices->device_list_mutex);
1755                                 return ret;
1756                         }
1757
1758                         rcu_read_lock();
1759
1760                         /* calc the free space in [0, skip_space - 1] */
1761                         skip_space -= used_space;
1762                 }
1763
1764                 /*
1765                  * we can use the free space in [0, skip_space - 1], subtract
1766                  * it from the total.
1767                  */
1768                 if (avail_space && avail_space >= skip_space)
1769                         avail_space -= skip_space;
1770                 else
1771                         avail_space = 0;
1772
1773                 if (avail_space < min_stripe_size)
1774                         continue;
1775
1776                 devices_info[i].dev = device;
1777                 devices_info[i].max_avail = avail_space;
1778
1779                 i++;
1780         }
1781         rcu_read_unlock();
1782         if (fs_info->alloc_start)
1783                 mutex_unlock(&fs_devices->device_list_mutex);
1784
1785         nr_devices = i;
1786
1787         btrfs_descending_sort_devices(devices_info, nr_devices);
1788
1789         i = nr_devices - 1;
1790         avail_space = 0;
1791         while (nr_devices >= min_stripes) {
1792                 if (num_stripes > nr_devices)
1793                         num_stripes = nr_devices;
1794
1795                 if (devices_info[i].max_avail >= min_stripe_size) {
1796                         int j;
1797                         u64 alloc_size;
1798
1799                         avail_space += devices_info[i].max_avail * num_stripes;
1800                         alloc_size = devices_info[i].max_avail;
1801                         for (j = i + 1 - num_stripes; j <= i; j++)
1802                                 devices_info[j].max_avail -= alloc_size;
1803                 }
1804                 i--;
1805                 nr_devices--;
1806         }
1807
1808         kfree(devices_info);
1809         *free_bytes = avail_space;
1810         return 0;
1811 }
1812
1813 /*
1814  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1815  *
1816  * If there's a redundant raid level at DATA block groups, use the respective
1817  * multiplier to scale the sizes.
1818  *
1819  * Unused device space usage is based on simulating the chunk allocator
1820  * algorithm that respects the device sizes, order of allocations and the
1821  * 'alloc_start' value, this is a close approximation of the actual use but
1822  * there are other factors that may change the result (like a new metadata
1823  * chunk).
1824  *
1825  * FIXME: not accurate for mixed block groups, total and free/used are ok,
1826  * available appears slightly larger.
1827  */
1828 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1829 {
1830         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1831         struct btrfs_super_block *disk_super = fs_info->super_copy;
1832         struct list_head *head = &fs_info->space_info;
1833         struct btrfs_space_info *found;
1834         u64 total_used = 0;
1835         u64 total_free_data = 0;
1836         int bits = dentry->d_sb->s_blocksize_bits;
1837         __be32 *fsid = (__be32 *)fs_info->fsid;
1838         unsigned factor = 1;
1839         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1840         int ret;
1841
1842         /*
1843          * holding chunk_muext to avoid allocating new chunks, holding
1844          * device_list_mutex to avoid the device being removed
1845          */
1846         rcu_read_lock();
1847         list_for_each_entry_rcu(found, head, list) {
1848                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1849                         int i;
1850
1851                         total_free_data += found->disk_total - found->disk_used;
1852                         total_free_data -=
1853                                 btrfs_account_ro_block_groups_free_space(found);
1854
1855                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1856                                 if (!list_empty(&found->block_groups[i])) {
1857                                         switch (i) {
1858                                         case BTRFS_RAID_DUP:
1859                                         case BTRFS_RAID_RAID1:
1860                                         case BTRFS_RAID_RAID10:
1861                                                 factor = 2;
1862                                         }
1863                                 }
1864                         }
1865                 }
1866
1867                 total_used += found->disk_used;
1868         }
1869
1870         rcu_read_unlock();
1871
1872         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
1873         buf->f_blocks >>= bits;
1874         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
1875
1876         /* Account global block reserve as used, it's in logical size already */
1877         spin_lock(&block_rsv->lock);
1878         buf->f_bfree -= block_rsv->size >> bits;
1879         spin_unlock(&block_rsv->lock);
1880
1881         buf->f_bavail = div_u64(total_free_data, factor);
1882         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1883         if (ret)
1884                 return ret;
1885         buf->f_bavail += div_u64(total_free_data, factor);
1886         buf->f_bavail = buf->f_bavail >> bits;
1887
1888         buf->f_type = BTRFS_SUPER_MAGIC;
1889         buf->f_bsize = dentry->d_sb->s_blocksize;
1890         buf->f_namelen = BTRFS_NAME_LEN;
1891
1892         /* We treat it as constant endianness (it doesn't matter _which_)
1893            because we want the fsid to come out the same whether mounted
1894            on a big-endian or little-endian host */
1895         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1896         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1897         /* Mask in the root object ID too, to disambiguate subvols */
1898         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
1899         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
1900
1901         return 0;
1902 }
1903
1904 static void btrfs_kill_super(struct super_block *sb)
1905 {
1906         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1907         kill_anon_super(sb);
1908         free_fs_info(fs_info);
1909 }
1910
1911 static struct file_system_type btrfs_fs_type = {
1912         .owner          = THIS_MODULE,
1913         .name           = "btrfs",
1914         .mount          = btrfs_mount,
1915         .kill_sb        = btrfs_kill_super,
1916         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
1917 };
1918 MODULE_ALIAS_FS("btrfs");
1919
1920 static int btrfs_control_open(struct inode *inode, struct file *file)
1921 {
1922         /*
1923          * The control file's private_data is used to hold the
1924          * transaction when it is started and is used to keep
1925          * track of whether a transaction is already in progress.
1926          */
1927         file->private_data = NULL;
1928         return 0;
1929 }
1930
1931 /*
1932  * used by btrfsctl to scan devices when no FS is mounted
1933  */
1934 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1935                                 unsigned long arg)
1936 {
1937         struct btrfs_ioctl_vol_args *vol;
1938         struct btrfs_fs_devices *fs_devices;
1939         int ret = -ENOTTY;
1940
1941         if (!capable(CAP_SYS_ADMIN))
1942                 return -EPERM;
1943
1944         vol = memdup_user((void __user *)arg, sizeof(*vol));
1945         if (IS_ERR(vol))
1946                 return PTR_ERR(vol);
1947
1948         switch (cmd) {
1949         case BTRFS_IOC_SCAN_DEV:
1950                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1951                                             &btrfs_fs_type, &fs_devices);
1952                 break;
1953         case BTRFS_IOC_DEVICES_READY:
1954                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1955                                             &btrfs_fs_type, &fs_devices);
1956                 if (ret)
1957                         break;
1958                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
1959                 break;
1960         }
1961
1962         kfree(vol);
1963         return ret;
1964 }
1965
1966 static int btrfs_freeze(struct super_block *sb)
1967 {
1968         struct btrfs_trans_handle *trans;
1969         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
1970
1971         trans = btrfs_attach_transaction_barrier(root);
1972         if (IS_ERR(trans)) {
1973                 /* no transaction, don't bother */
1974                 if (PTR_ERR(trans) == -ENOENT)
1975                         return 0;
1976                 return PTR_ERR(trans);
1977         }
1978         return btrfs_commit_transaction(trans, root);
1979 }
1980
1981 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
1982 {
1983         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
1984         struct btrfs_fs_devices *cur_devices;
1985         struct btrfs_device *dev, *first_dev = NULL;
1986         struct list_head *head;
1987         struct rcu_string *name;
1988
1989         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1990         cur_devices = fs_info->fs_devices;
1991         while (cur_devices) {
1992                 head = &cur_devices->devices;
1993                 list_for_each_entry(dev, head, dev_list) {
1994                         if (dev->missing)
1995                                 continue;
1996                         if (!dev->name)
1997                                 continue;
1998                         if (!first_dev || dev->devid < first_dev->devid)
1999                                 first_dev = dev;
2000                 }
2001                 cur_devices = cur_devices->seed;
2002         }
2003
2004         if (first_dev) {
2005                 rcu_read_lock();
2006                 name = rcu_dereference(first_dev->name);
2007                 seq_escape(m, name->str, " \t\n\\");
2008                 rcu_read_unlock();
2009         } else {
2010                 WARN_ON(1);
2011         }
2012         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2013         return 0;
2014 }
2015
2016 static const struct super_operations btrfs_super_ops = {
2017         .drop_inode     = btrfs_drop_inode,
2018         .evict_inode    = btrfs_evict_inode,
2019         .put_super      = btrfs_put_super,
2020         .sync_fs        = btrfs_sync_fs,
2021         .show_options   = btrfs_show_options,
2022         .show_devname   = btrfs_show_devname,
2023         .write_inode    = btrfs_write_inode,
2024         .alloc_inode    = btrfs_alloc_inode,
2025         .destroy_inode  = btrfs_destroy_inode,
2026         .statfs         = btrfs_statfs,
2027         .remount_fs     = btrfs_remount,
2028         .freeze_fs      = btrfs_freeze,
2029 };
2030
2031 static const struct file_operations btrfs_ctl_fops = {
2032         .open = btrfs_control_open,
2033         .unlocked_ioctl  = btrfs_control_ioctl,
2034         .compat_ioctl = btrfs_control_ioctl,
2035         .owner   = THIS_MODULE,
2036         .llseek = noop_llseek,
2037 };
2038
2039 static struct miscdevice btrfs_misc = {
2040         .minor          = BTRFS_MINOR,
2041         .name           = "btrfs-control",
2042         .fops           = &btrfs_ctl_fops
2043 };
2044
2045 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2046 MODULE_ALIAS("devname:btrfs-control");
2047
2048 static int btrfs_interface_init(void)
2049 {
2050         return misc_register(&btrfs_misc);
2051 }
2052
2053 static void btrfs_interface_exit(void)
2054 {
2055         if (misc_deregister(&btrfs_misc) < 0)
2056                 printk(KERN_INFO "BTRFS: misc_deregister failed for control device\n");
2057 }
2058
2059 static void btrfs_print_info(void)
2060 {
2061         printk(KERN_INFO "Btrfs loaded"
2062 #ifdef CONFIG_BTRFS_DEBUG
2063                         ", debug=on"
2064 #endif
2065 #ifdef CONFIG_BTRFS_ASSERT
2066                         ", assert=on"
2067 #endif
2068 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2069                         ", integrity-checker=on"
2070 #endif
2071                         "\n");
2072 }
2073
2074 static int btrfs_run_sanity_tests(void)
2075 {
2076         int ret;
2077
2078         ret = btrfs_init_test_fs();
2079         if (ret)
2080                 return ret;
2081
2082         ret = btrfs_test_free_space_cache();
2083         if (ret)
2084                 goto out;
2085         ret = btrfs_test_extent_buffer_operations();
2086         if (ret)
2087                 goto out;
2088         ret = btrfs_test_extent_io();
2089         if (ret)
2090                 goto out;
2091         ret = btrfs_test_inodes();
2092         if (ret)
2093                 goto out;
2094         ret = btrfs_test_qgroups();
2095 out:
2096         btrfs_destroy_test_fs();
2097         return ret;
2098 }
2099
2100 static int __init init_btrfs_fs(void)
2101 {
2102         int err;
2103
2104         err = btrfs_hash_init();
2105         if (err)
2106                 return err;
2107
2108         btrfs_props_init();
2109
2110         err = btrfs_init_sysfs();
2111         if (err)
2112                 goto free_hash;
2113
2114         btrfs_init_compress();
2115
2116         err = btrfs_init_cachep();
2117         if (err)
2118                 goto free_compress;
2119
2120         err = extent_io_init();
2121         if (err)
2122                 goto free_cachep;
2123
2124         err = extent_map_init();
2125         if (err)
2126                 goto free_extent_io;
2127
2128         err = ordered_data_init();
2129         if (err)
2130                 goto free_extent_map;
2131
2132         err = btrfs_delayed_inode_init();
2133         if (err)
2134                 goto free_ordered_data;
2135
2136         err = btrfs_auto_defrag_init();
2137         if (err)
2138                 goto free_delayed_inode;
2139
2140         err = btrfs_delayed_ref_init();
2141         if (err)
2142                 goto free_auto_defrag;
2143
2144         err = btrfs_prelim_ref_init();
2145         if (err)
2146                 goto free_delayed_ref;
2147
2148         err = btrfs_end_io_wq_init();
2149         if (err)
2150                 goto free_prelim_ref;
2151
2152         err = btrfs_interface_init();
2153         if (err)
2154                 goto free_end_io_wq;
2155
2156         btrfs_init_lockdep();
2157
2158         btrfs_print_info();
2159
2160         err = btrfs_run_sanity_tests();
2161         if (err)
2162                 goto unregister_ioctl;
2163
2164         err = register_filesystem(&btrfs_fs_type);
2165         if (err)
2166                 goto unregister_ioctl;
2167
2168         return 0;
2169
2170 unregister_ioctl:
2171         btrfs_interface_exit();
2172 free_end_io_wq:
2173         btrfs_end_io_wq_exit();
2174 free_prelim_ref:
2175         btrfs_prelim_ref_exit();
2176 free_delayed_ref:
2177         btrfs_delayed_ref_exit();
2178 free_auto_defrag:
2179         btrfs_auto_defrag_exit();
2180 free_delayed_inode:
2181         btrfs_delayed_inode_exit();
2182 free_ordered_data:
2183         ordered_data_exit();
2184 free_extent_map:
2185         extent_map_exit();
2186 free_extent_io:
2187         extent_io_exit();
2188 free_cachep:
2189         btrfs_destroy_cachep();
2190 free_compress:
2191         btrfs_exit_compress();
2192         btrfs_exit_sysfs();
2193 free_hash:
2194         btrfs_hash_exit();
2195         return err;
2196 }
2197
2198 static void __exit exit_btrfs_fs(void)
2199 {
2200         btrfs_destroy_cachep();
2201         btrfs_delayed_ref_exit();
2202         btrfs_auto_defrag_exit();
2203         btrfs_delayed_inode_exit();
2204         btrfs_prelim_ref_exit();
2205         ordered_data_exit();
2206         extent_map_exit();
2207         extent_io_exit();
2208         btrfs_interface_exit();
2209         btrfs_end_io_wq_exit();
2210         unregister_filesystem(&btrfs_fs_type);
2211         btrfs_exit_sysfs();
2212         btrfs_cleanup_fs_uuids();
2213         btrfs_exit_compress();
2214         btrfs_hash_exit();
2215 }
2216
2217 late_initcall(init_btrfs_fs);
2218 module_exit(exit_btrfs_fs)
2219
2220 MODULE_LICENSE("GPL");