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 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 /*
 134  * __btrfs_std_error decodes expected errors from the caller and
 135  * invokes the approciate error response.
 136  */
 137 __cold
 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 #ifdef CONFIG_PRINTK
 143         const char *errstr;
 144 #endif
 145
 146         /*
 147          * Special case: if the error is EROFS, and we're already
 148          * under MS_RDONLY, then it is safe here.
 149          */
 150         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 151                 return;
 152
 153 #ifdef CONFIG_PRINTK
 154         errstr = btrfs_decode_error(errno);
 155         if (fmt) {
 156                 struct va_format vaf;
 157                 va_list args;
 158
 159                 va_start(args, fmt);
 160                 vaf.fmt = fmt;
 161                 vaf.va = &args;
 162
 163                 printk(KERN_CRIT
 164                         "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 165                         sb->s_id, function, line, errno, errstr, &vaf);
 166                 va_end(args);
 167         } else {
 168                 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 169                         sb->s_id, function, line, errno, errstr);
 170         }
 171 #endif
 172
 173         /* Don't go through full error handling during mount */
 174         save_error_info(fs_info);
 175         if (sb->s_flags & MS_BORN)
 176                 btrfs_handle_error(fs_info);
 177 }
 178
 179 #ifdef CONFIG_PRINTK
 180 static const char * const logtypes[] = {
 181         "emergency",
 182         "alert",
 183         "critical",
 184         "error",
 185         "warning",
 186         "notice",
 187         "info",
 188         "debug",
 189 };
 190
 191 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 192 {
 193         struct super_block *sb = fs_info->sb;
 194         char lvl[4];
 195         struct va_format vaf;
 196         va_list args;
 197         const char *type = logtypes[4];
 198         int kern_level;
 199
 200         va_start(args, fmt);
 201
 202         kern_level = printk_get_level(fmt);
 203         if (kern_level) {
 204                 size_t size = printk_skip_level(fmt) - fmt;
 205                 memcpy(lvl, fmt,  size);
 206                 lvl[size] = '\0';
 207                 fmt += size;
 208                 type = logtypes[kern_level - '0'];
 209         } else
 210                 *lvl = '\0';
 211
 212         vaf.fmt = fmt;
 213         vaf.va = &args;
 214
 215         printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
 216
 217         va_end(args);
 218 }
 219 #endif
 220
 221 /*
 222  * We only mark the transaction aborted and then set the file system read-only.
 223  * This will prevent new transactions from starting or trying to join this
 224  * one.
 225  *
 226  * This means that error recovery at the call site is limited to freeing
 227  * any local memory allocations and passing the error code up without
 228  * further cleanup. The transaction should complete as it normally would
 229  * in the call path but will return -EIO.
 230  *
 231  * We'll complete the cleanup in btrfs_end_transaction and
 232  * btrfs_commit_transaction.
 233  */
 234 __cold
 235 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 236                                struct btrfs_root *root, const char *function,
 237                                unsigned int line, int errno)
 238 {
 239         trans->aborted = errno;
 240         /* Nothing used. The other threads that have joined this
 241          * transaction may be able to continue. */
 242         if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
 243                 const char *errstr;
 244
 245                 errstr = btrfs_decode_error(errno);
 246                 btrfs_warn(root->fs_info,
 247                            "%s:%d: Aborting unused transaction(%s).",
 248                            function, line, errstr);
 249                 return;
 250         }
 251         ACCESS_ONCE(trans->transaction->aborted) = errno;
 252         /* Wake up anybody who may be waiting on this transaction */
 253         wake_up(&root->fs_info->transaction_wait);
 254         wake_up(&root->fs_info->transaction_blocked_wait);
 255         __btrfs_std_error(root->fs_info, function, line, errno, NULL);
 256 }
 257 /*
 258  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 259  * issues an alert, and either panics or BUGs, depending on mount options.
 260  */
 261 __cold
 262 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 263                    unsigned int line, int errno, const char *fmt, ...)
 264 {
 265         char *s_id = "<unknown>";
 266         const char *errstr;
 267         struct va_format vaf = { .fmt = fmt };
 268         va_list args;
 269
 270         if (fs_info)
 271                 s_id = fs_info->sb->s_id;
 272
 273         va_start(args, fmt);
 274         vaf.va = &args;
 275
 276         errstr = btrfs_decode_error(errno);
 277         if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
 278                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 279                         s_id, function, line, &vaf, errno, errstr);
 280
 281         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 282                    function, line, &vaf, errno, errstr);
 283         va_end(args);
 284         /* Caller calls BUG() */
 285 }
 286
 287 static void btrfs_put_super(struct super_block *sb)
 288 {
 289         close_ctree(btrfs_sb(sb)->tree_root);
 290 }
 291
 292 enum {
 293         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 294         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 295         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 296         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 297         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 298         Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 299         Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 300         Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 301         Opt_skip_balance, Opt_check_integrity,
 302         Opt_check_integrity_including_extent_data,
 303         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 304         Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
 305         Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
 306         Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
 307         Opt_nologreplay, Opt_norecovery,
 308 #ifdef CONFIG_BTRFS_DEBUG
 309         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 310 #endif
 311         Opt_err,
 312 };
 313
 314 static const match_table_t tokens = {
 315         {Opt_degraded, "degraded"},
 316         {Opt_subvol, "subvol=%s"},
 317         {Opt_subvolid, "subvolid=%s"},
 318         {Opt_device, "device=%s"},
 319         {Opt_nodatasum, "nodatasum"},
 320         {Opt_datasum, "datasum"},
 321         {Opt_nodatacow, "nodatacow"},
 322         {Opt_datacow, "datacow"},
 323         {Opt_nobarrier, "nobarrier"},
 324         {Opt_barrier, "barrier"},
 325         {Opt_max_inline, "max_inline=%s"},
 326         {Opt_alloc_start, "alloc_start=%s"},
 327         {Opt_thread_pool, "thread_pool=%d"},
 328         {Opt_compress, "compress"},
 329         {Opt_compress_type, "compress=%s"},
 330         {Opt_compress_force, "compress-force"},
 331         {Opt_compress_force_type, "compress-force=%s"},
 332         {Opt_ssd, "ssd"},
 333         {Opt_ssd_spread, "ssd_spread"},
 334         {Opt_nossd, "nossd"},
 335         {Opt_acl, "acl"},
 336         {Opt_noacl, "noacl"},
 337         {Opt_notreelog, "notreelog"},
 338         {Opt_treelog, "treelog"},
 339         {Opt_nologreplay, "nologreplay"},
 340         {Opt_norecovery, "norecovery"},
 341         {Opt_flushoncommit, "flushoncommit"},
 342         {Opt_noflushoncommit, "noflushoncommit"},
 343         {Opt_ratio, "metadata_ratio=%d"},
 344         {Opt_discard, "discard"},
 345         {Opt_nodiscard, "nodiscard"},
 346         {Opt_space_cache, "space_cache"},
 347         {Opt_space_cache_version, "space_cache=%s"},
 348         {Opt_clear_cache, "clear_cache"},
 349         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 350         {Opt_enospc_debug, "enospc_debug"},
 351         {Opt_noenospc_debug, "noenospc_debug"},
 352         {Opt_subvolrootid, "subvolrootid=%d"},
 353         {Opt_defrag, "autodefrag"},
 354         {Opt_nodefrag, "noautodefrag"},
 355         {Opt_inode_cache, "inode_cache"},
 356         {Opt_noinode_cache, "noinode_cache"},
 357         {Opt_no_space_cache, "nospace_cache"},
 358         {Opt_recovery, "recovery"}, /* deprecated */
 359         {Opt_usebackuproot, "usebackuproot"},
 360         {Opt_skip_balance, "skip_balance"},
 361         {Opt_check_integrity, "check_int"},
 362         {Opt_check_integrity_including_extent_data, "check_int_data"},
 363         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 364         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 365         {Opt_fatal_errors, "fatal_errors=%s"},
 366         {Opt_commit_interval, "commit=%d"},
 367 #ifdef CONFIG_BTRFS_DEBUG
 368         {Opt_fragment_data, "fragment=data"},
 369         {Opt_fragment_metadata, "fragment=metadata"},
 370         {Opt_fragment_all, "fragment=all"},
 371 #endif
 372         {Opt_err, NULL},
 373 };
 374
 375 /*
 376  * Regular mount options parser.  Everything that is needed only when
 377  * reading in a new superblock is parsed here.
 378  * XXX JDM: This needs to be cleaned up for remount.
 379  */
 380 int btrfs_parse_options(struct btrfs_root *root, char *options,
 381                         unsigned long new_flags)
 382 {
 383         struct btrfs_fs_info *info = root->fs_info;
 384         substring_t args[MAX_OPT_ARGS];
 385         char *p, *num, *orig = NULL;
 386         u64 cache_gen;
 387         int intarg;
 388         int ret = 0;
 389         char *compress_type;
 390         bool compress_force = false;
 391         enum btrfs_compression_type saved_compress_type;
 392         bool saved_compress_force;
 393         int no_compress = 0;
 394
 395         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 396         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
 397                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 398         else if (cache_gen)
 399                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 400
 401         /*
 402          * Even the options are empty, we still need to do extra check
 403          * against new flags
 404          */
 405         if (!options)
 406                 goto check;
 407
 408         /*
 409          * strsep changes the string, duplicate it because parse_options
 410          * gets called twice
 411          */
 412         options = kstrdup(options, GFP_NOFS);
 413         if (!options)
 414                 return -ENOMEM;
 415
 416         orig = options;
 417
 418         while ((p = strsep(&options, ",")) != NULL) {
 419                 int token;
 420                 if (!*p)
 421                         continue;
 422
 423                 token = match_token(p, tokens, args);
 424                 switch (token) {
 425                 case Opt_degraded:
 426                         btrfs_info(root->fs_info, "allowing degraded mounts");
 427                         btrfs_set_opt(info->mount_opt, DEGRADED);
 428                         break;
 429                 case Opt_subvol:
 430                 case Opt_subvolid:
 431                 case Opt_subvolrootid:
 432                 case Opt_device:
 433                         /*
 434                          * These are parsed by btrfs_parse_early_options
 435                          * and can be happily ignored here.
 436                          */
 437                         break;
 438                 case Opt_nodatasum:
 439                         btrfs_set_and_info(root, NODATASUM,
 440                                            "setting nodatasum");
 441                         break;
 442                 case Opt_datasum:
 443                         if (btrfs_test_opt(root, NODATASUM)) {
 444                                 if (btrfs_test_opt(root, NODATACOW))
 445                                         btrfs_info(root->fs_info, "setting datasum, datacow enabled");
 446                                 else
 447                                         btrfs_info(root->fs_info, "setting datasum");
 448                         }
 449                         btrfs_clear_opt(info->mount_opt, NODATACOW);
 450                         btrfs_clear_opt(info->mount_opt, NODATASUM);
 451                         break;
 452                 case Opt_nodatacow:
 453                         if (!btrfs_test_opt(root, NODATACOW)) {
 454                                 if (!btrfs_test_opt(root, COMPRESS) ||
 455                                     !btrfs_test_opt(root, FORCE_COMPRESS)) {
 456                                         btrfs_info(root->fs_info,
 457                                                    "setting nodatacow, compression disabled");
 458                                 } else {
 459                                         btrfs_info(root->fs_info, "setting nodatacow");
 460                                 }
 461                         }
 462                         btrfs_clear_opt(info->mount_opt, COMPRESS);
 463                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 464                         btrfs_set_opt(info->mount_opt, NODATACOW);
 465                         btrfs_set_opt(info->mount_opt, NODATASUM);
 466                         break;
 467                 case Opt_datacow:
 468                         btrfs_clear_and_info(root, NODATACOW,
 469                                              "setting datacow");
 470                         break;
 471                 case Opt_compress_force:
 472                 case Opt_compress_force_type:
 473                         compress_force = true;
 474                         /* Fallthrough */
 475                 case Opt_compress:
 476                 case Opt_compress_type:
 477                         saved_compress_type = btrfs_test_opt(root, COMPRESS) ?
 478                                 info->compress_type : BTRFS_COMPRESS_NONE;
 479                         saved_compress_force =
 480                                 btrfs_test_opt(root, FORCE_COMPRESS);
 481                         if (token == Opt_compress ||
 482                             token == Opt_compress_force ||
 483                             strcmp(args[0].from, "zlib") == 0) {
 484                                 compress_type = "zlib";
 485                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 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                                 no_compress = 0;
 490                         } else if (strcmp(args[0].from, "lzo") == 0) {
 491                                 compress_type = "lzo";
 492                                 info->compress_type = BTRFS_COMPRESS_LZO;
 493                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 494                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
 495                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
 496                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 497                                 no_compress = 0;
 498                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 499                                 compress_type = "no";
 500                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 501                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 502                                 compress_force = false;
 503                                 no_compress++;
 504                         } else {
 505                                 ret = -EINVAL;
 506                                 goto out;
 507                         }
 508
 509                         if (compress_force) {
 510                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 511                         } else {
 512                                 /*
 513                                  * If we remount from compress-force=xxx to
 514                                  * compress=xxx, we need clear FORCE_COMPRESS
 515                                  * flag, otherwise, there is no way for users
 516                                  * to disable forcible compression separately.
 517                                  */
 518                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 519                         }
 520                         if ((btrfs_test_opt(root, COMPRESS) &&
 521                              (info->compress_type != saved_compress_type ||
 522                               compress_force != saved_compress_force)) ||
 523                             (!btrfs_test_opt(root, COMPRESS) &&
 524                              no_compress == 1)) {
 525                                 btrfs_info(root->fs_info,
 526                                            "%s %s compression",
 527                                            (compress_force) ? "force" : "use",
 528                                            compress_type);
 529                         }
 530                         compress_force = false;
 531                         break;
 532                 case Opt_ssd:
 533                         btrfs_set_and_info(root, SSD,
 534                                            "use ssd allocation scheme");
 535                         break;
 536                 case Opt_ssd_spread:
 537                         btrfs_set_and_info(root, SSD_SPREAD,
 538                                            "use spread ssd allocation scheme");
 539                         btrfs_set_opt(info->mount_opt, SSD);
 540                         break;
 541                 case Opt_nossd:
 542                         btrfs_set_and_info(root, NOSSD,
 543                                              "not using ssd allocation scheme");
 544                         btrfs_clear_opt(info->mount_opt, SSD);
 545                         break;
 546                 case Opt_barrier:
 547                         btrfs_clear_and_info(root, NOBARRIER,
 548                                              "turning on barriers");
 549                         break;
 550                 case Opt_nobarrier:
 551                         btrfs_set_and_info(root, NOBARRIER,
 552                                            "turning off barriers");
 553                         break;
 554                 case Opt_thread_pool:
 555                         ret = match_int(&args[0], &intarg);
 556                         if (ret) {
 557                                 goto out;
 558                         } else if (intarg > 0) {
 559                                 info->thread_pool_size = intarg;
 560                         } else {
 561                                 ret = -EINVAL;
 562                                 goto out;
 563                         }
 564                         break;
 565                 case Opt_max_inline:
 566                         num = match_strdup(&args[0]);
 567                         if (num) {
 568                                 info->max_inline = memparse(num, NULL);
 569                                 kfree(num);
 570
 571                                 if (info->max_inline) {
 572                                         info->max_inline = min_t(u64,
 573                                                 info->max_inline,
 574                                                 root->sectorsize);
 575                                 }
 576                                 btrfs_info(root->fs_info, "max_inline at %llu",
 577                                         info->max_inline);
 578                         } else {
 579                                 ret = -ENOMEM;
 580                                 goto out;
 581                         }
 582                         break;
 583                 case Opt_alloc_start:
 584                         num = match_strdup(&args[0]);
 585                         if (num) {
 586                                 mutex_lock(&info->chunk_mutex);
 587                                 info->alloc_start = memparse(num, NULL);
 588                                 mutex_unlock(&info->chunk_mutex);
 589                                 kfree(num);
 590                                 btrfs_info(root->fs_info, "allocations start at %llu",
 591                                         info->alloc_start);
 592                         } else {
 593                                 ret = -ENOMEM;
 594                                 goto out;
 595                         }
 596                         break;
 597                 case Opt_acl:
 598 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 599                         root->fs_info->sb->s_flags |= MS_POSIXACL;
 600                         break;
 601 #else
 602                         btrfs_err(root->fs_info,
 603                                 "support for ACL not compiled in!");
 604                         ret = -EINVAL;
 605                         goto out;
 606 #endif
 607                 case Opt_noacl:
 608                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 609                         break;
 610                 case Opt_notreelog:
 611                         btrfs_set_and_info(root, NOTREELOG,
 612                                            "disabling tree log");
 613                         break;
 614                 case Opt_treelog:
 615                         btrfs_clear_and_info(root, NOTREELOG,
 616                                              "enabling tree log");
 617                         break;
 618                 case Opt_norecovery:
 619                 case Opt_nologreplay:
 620                         btrfs_set_and_info(root, NOLOGREPLAY,
 621                                            "disabling log replay at mount time");
 622                         break;
 623                 case Opt_flushoncommit:
 624                         btrfs_set_and_info(root, FLUSHONCOMMIT,
 625                                            "turning on flush-on-commit");
 626                         break;
 627                 case Opt_noflushoncommit:
 628                         btrfs_clear_and_info(root, FLUSHONCOMMIT,
 629                                              "turning off flush-on-commit");
 630                         break;
 631                 case Opt_ratio:
 632                         ret = match_int(&args[0], &intarg);
 633                         if (ret) {
 634                                 goto out;
 635                         } else if (intarg >= 0) {
 636                                 info->metadata_ratio = intarg;
 637                                 btrfs_info(root->fs_info, "metadata ratio %d",
 638                                        info->metadata_ratio);
 639                         } else {
 640                                 ret = -EINVAL;
 641                                 goto out;
 642                         }
 643                         break;
 644                 case Opt_discard:
 645                         btrfs_set_and_info(root, DISCARD,
 646                                            "turning on discard");
 647                         break;
 648                 case Opt_nodiscard:
 649                         btrfs_clear_and_info(root, DISCARD,
 650                                              "turning off discard");
 651                         break;
 652                 case Opt_space_cache:
 653                 case Opt_space_cache_version:
 654                         if (token == Opt_space_cache ||
 655                             strcmp(args[0].from, "v1") == 0) {
 656                                 btrfs_clear_opt(root->fs_info->mount_opt,
 657                                                 FREE_SPACE_TREE);
 658                                 btrfs_set_and_info(root, SPACE_CACHE,
 659                                                    "enabling disk space caching");
 660                         } else if (strcmp(args[0].from, "v2") == 0) {
 661                                 btrfs_clear_opt(root->fs_info->mount_opt,
 662                                                 SPACE_CACHE);
 663                                 btrfs_set_and_info(root, FREE_SPACE_TREE,
 664                                                    "enabling free space tree");
 665                         } else {
 666                                 ret = -EINVAL;
 667                                 goto out;
 668                         }
 669                         break;
 670                 case Opt_rescan_uuid_tree:
 671                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 672                         break;
 673                 case Opt_no_space_cache:
 674                         if (btrfs_test_opt(root, SPACE_CACHE)) {
 675                                 btrfs_clear_and_info(root, SPACE_CACHE,
 676                                                      "disabling disk space caching");
 677                         }
 678                         if (btrfs_test_opt(root, FREE_SPACE_TREE)) {
 679                                 btrfs_clear_and_info(root, FREE_SPACE_TREE,
 680                                                      "disabling free space tree");
 681                         }
 682                         break;
 683                 case Opt_inode_cache:
 684                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 685                                            "enabling inode map caching");
 686                         break;
 687                 case Opt_noinode_cache:
 688                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 689                                              "disabling inode map caching");
 690                         break;
 691                 case Opt_clear_cache:
 692                         btrfs_set_and_info(root, CLEAR_CACHE,
 693                                            "force clearing of disk cache");
 694                         break;
 695                 case Opt_user_subvol_rm_allowed:
 696                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 697                         break;
 698                 case Opt_enospc_debug:
 699                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 700                         break;
 701                 case Opt_noenospc_debug:
 702                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 703                         break;
 704                 case Opt_defrag:
 705                         btrfs_set_and_info(root, AUTO_DEFRAG,
 706                                            "enabling auto defrag");
 707                         break;
 708                 case Opt_nodefrag:
 709                         btrfs_clear_and_info(root, AUTO_DEFRAG,
 710                                              "disabling auto defrag");
 711                         break;
 712                 case Opt_recovery:
 713                         btrfs_warn(root->fs_info,
 714                                    "'recovery' is deprecated, use 'usebackuproot' instead");
 715                 case Opt_usebackuproot:
 716                         btrfs_info(root->fs_info,
 717                                    "trying to use backup root at mount time");
 718                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 719                         break;
 720                 case Opt_skip_balance:
 721                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 722                         break;
 723 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 724                 case Opt_check_integrity_including_extent_data:
 725                         btrfs_info(root->fs_info,
 726                                    "enabling check integrity including extent data");
 727                         btrfs_set_opt(info->mount_opt,
 728                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 729                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 730                         break;
 731                 case Opt_check_integrity:
 732                         btrfs_info(root->fs_info, "enabling check integrity");
 733                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 734                         break;
 735                 case Opt_check_integrity_print_mask:
 736                         ret = match_int(&args[0], &intarg);
 737                         if (ret) {
 738                                 goto out;
 739                         } else if (intarg >= 0) {
 740                                 info->check_integrity_print_mask = intarg;
 741                                 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
 742                                        info->check_integrity_print_mask);
 743                         } else {
 744                                 ret = -EINVAL;
 745                                 goto out;
 746                         }
 747                         break;
 748 #else
 749                 case Opt_check_integrity_including_extent_data:
 750                 case Opt_check_integrity:
 751                 case Opt_check_integrity_print_mask:
 752                         btrfs_err(root->fs_info,
 753                                 "support for check_integrity* not compiled in!");
 754                         ret = -EINVAL;
 755                         goto out;
 756 #endif
 757                 case Opt_fatal_errors:
 758                         if (strcmp(args[0].from, "panic") == 0)
 759                                 btrfs_set_opt(info->mount_opt,
 760                                               PANIC_ON_FATAL_ERROR);
 761                         else if (strcmp(args[0].from, "bug") == 0)
 762                                 btrfs_clear_opt(info->mount_opt,
 763                                               PANIC_ON_FATAL_ERROR);
 764                         else {
 765                                 ret = -EINVAL;
 766                                 goto out;
 767                         }
 768                         break;
 769                 case Opt_commit_interval:
 770                         intarg = 0;
 771                         ret = match_int(&args[0], &intarg);
 772                         if (ret < 0) {
 773                                 btrfs_err(root->fs_info, "invalid commit interval");
 774                                 ret = -EINVAL;
 775                                 goto out;
 776                         }
 777                         if (intarg > 0) {
 778                                 if (intarg > 300) {
 779                                         btrfs_warn(root->fs_info, "excessive commit interval %d",
 780                                                         intarg);
 781                                 }
 782                                 info->commit_interval = intarg;
 783                         } else {
 784                                 btrfs_info(root->fs_info, "using default commit interval %ds",
 785                                     BTRFS_DEFAULT_COMMIT_INTERVAL);
 786                                 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 787                         }
 788                         break;
 789 #ifdef CONFIG_BTRFS_DEBUG
 790                 case Opt_fragment_all:
 791                         btrfs_info(root->fs_info, "fragmenting all space");
 792                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 793                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 794                         break;
 795                 case Opt_fragment_metadata:
 796                         btrfs_info(root->fs_info, "fragmenting metadata");
 797                         btrfs_set_opt(info->mount_opt,
 798                                       FRAGMENT_METADATA);
 799                         break;
 800                 case Opt_fragment_data:
 801                         btrfs_info(root->fs_info, "fragmenting data");
 802                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 803                         break;
 804 #endif
 805                 case Opt_err:
 806                         btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
 807                         ret = -EINVAL;
 808                         goto out;
 809                 default:
 810                         break;
 811                 }
 812         }
 813 check:
 814         /*
 815          * Extra check for current option against current flag
 816          */
 817         if (btrfs_test_opt(root, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
 818                 btrfs_err(root->fs_info,
 819                           "nologreplay must be used with ro mount option");
 820                 ret = -EINVAL;
 821         }
 822 out:
 823         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
 824             !btrfs_test_opt(root, FREE_SPACE_TREE) &&
 825             !btrfs_test_opt(root, CLEAR_CACHE)) {
 826                 btrfs_err(root->fs_info, "cannot disable free space tree");
 827                 ret = -EINVAL;
 828
 829         }
 830         if (!ret && btrfs_test_opt(root, SPACE_CACHE))
 831                 btrfs_info(root->fs_info, "disk space caching is enabled");
 832         if (!ret && btrfs_test_opt(root, FREE_SPACE_TREE))
 833                 btrfs_info(root->fs_info, "using free space tree");
 834         kfree(orig);
 835         return ret;
 836 }
 837
 838 /*
 839  * Parse mount options that are required early in the mount process.
 840  *
 841  * All other options will be parsed on much later in the mount process and
 842  * only when we need to allocate a new super block.
 843  */
 844 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 845                 void *holder, char **subvol_name, u64 *subvol_objectid,
 846                 struct btrfs_fs_devices **fs_devices)
 847 {
 848         substring_t args[MAX_OPT_ARGS];
 849         char *device_name, *opts, *orig, *p;
 850         char *num = NULL;
 851         int error = 0;
 852
 853         if (!options)
 854                 return 0;
 855
 856         /*
 857          * strsep changes the string, duplicate it because parse_options
 858          * gets called twice
 859          */
 860         opts = kstrdup(options, GFP_KERNEL);
 861         if (!opts)
 862                 return -ENOMEM;
 863         orig = opts;
 864
 865         while ((p = strsep(&opts, ",")) != NULL) {
 866                 int token;
 867                 if (!*p)
 868                         continue;
 869
 870                 token = match_token(p, tokens, args);
 871                 switch (token) {
 872                 case Opt_subvol:
 873                         kfree(*subvol_name);
 874                         *subvol_name = match_strdup(&args[0]);
 875                         if (!*subvol_name) {
 876                                 error = -ENOMEM;
 877                                 goto out;
 878                         }
 879                         break;
 880                 case Opt_subvolid:
 881                         num = match_strdup(&args[0]);
 882                         if (num) {
 883                                 *subvol_objectid = memparse(num, NULL);
 884                                 kfree(num);
 885                                 /* we want the original fs_tree */
 886                                 if (!*subvol_objectid)
 887                                         *subvol_objectid =
 888                                                 BTRFS_FS_TREE_OBJECTID;
 889                         } else {
 890                                 error = -EINVAL;
 891                                 goto out;
 892                         }
 893                         break;
 894                 case Opt_subvolrootid:
 895                         printk(KERN_WARNING
 896                                 "BTRFS: 'subvolrootid' mount option is deprecated and has "
 897                                 "no effect\n");
 898                         break;
 899                 case Opt_device:
 900                         device_name = match_strdup(&args[0]);
 901                         if (!device_name) {
 902                                 error = -ENOMEM;
 903                                 goto out;
 904                         }
 905                         error = btrfs_scan_one_device(device_name,
 906                                         flags, holder, fs_devices);
 907                         kfree(device_name);
 908                         if (error)
 909                                 goto out;
 910                         break;
 911                 default:
 912                         break;
 913                 }
 914         }
 915
 916 out:
 917         kfree(orig);
 918         return error;
 919 }
 920
 921 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 922                                            u64 subvol_objectid)
 923 {
 924         struct btrfs_root *root = fs_info->tree_root;
 925         struct btrfs_root *fs_root;
 926         struct btrfs_root_ref *root_ref;
 927         struct btrfs_inode_ref *inode_ref;
 928         struct btrfs_key key;
 929         struct btrfs_path *path = NULL;
 930         char *name = NULL, *ptr;
 931         u64 dirid;
 932         int len;
 933         int ret;
 934
 935         path = btrfs_alloc_path();
 936         if (!path) {
 937                 ret = -ENOMEM;
 938                 goto err;
 939         }
 940         path->leave_spinning = 1;
 941
 942         name = kmalloc(PATH_MAX, GFP_NOFS);
 943         if (!name) {
 944                 ret = -ENOMEM;
 945                 goto err;
 946         }
 947         ptr = name + PATH_MAX - 1;
 948         ptr[0] = '\0';
 949
 950         /*
 951          * Walk up the subvolume trees in the tree of tree roots by root
 952          * backrefs until we hit the top-level subvolume.
 953          */
 954         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 955                 key.objectid = subvol_objectid;
 956                 key.type = BTRFS_ROOT_BACKREF_KEY;
 957                 key.offset = (u64)-1;
 958
 959                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 960                 if (ret < 0) {
 961                         goto err;
 962                 } else if (ret > 0) {
 963                         ret = btrfs_previous_item(root, path, subvol_objectid,
 964                                                   BTRFS_ROOT_BACKREF_KEY);
 965                         if (ret < 0) {
 966                                 goto err;
 967                         } else if (ret > 0) {
 968                                 ret = -ENOENT;
 969                                 goto err;
 970                         }
 971                 }
 972
 973                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 974                 subvol_objectid = key.offset;
 975
 976                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 977                                           struct btrfs_root_ref);
 978                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
 979                 ptr -= len + 1;
 980                 if (ptr < name) {
 981                         ret = -ENAMETOOLONG;
 982                         goto err;
 983                 }
 984                 read_extent_buffer(path->nodes[0], ptr + 1,
 985                                    (unsigned long)(root_ref + 1), len);
 986                 ptr[0] = '/';
 987                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
 988                 btrfs_release_path(path);
 989
 990                 key.objectid = subvol_objectid;
 991                 key.type = BTRFS_ROOT_ITEM_KEY;
 992                 key.offset = (u64)-1;
 993                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
 994                 if (IS_ERR(fs_root)) {
 995                         ret = PTR_ERR(fs_root);
 996                         goto err;
 997                 }
 998
 999                 /*
1000                  * Walk up the filesystem tree by inode refs until we hit the
1001                  * root directory.
1002                  */
1003                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1004                         key.objectid = dirid;
1005                         key.type = BTRFS_INODE_REF_KEY;
1006                         key.offset = (u64)-1;
1007
1008                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1009                         if (ret < 0) {
1010                                 goto err;
1011                         } else if (ret > 0) {
1012                                 ret = btrfs_previous_item(fs_root, path, dirid,
1013                                                           BTRFS_INODE_REF_KEY);
1014                                 if (ret < 0) {
1015                                         goto err;
1016                                 } else if (ret > 0) {
1017                                         ret = -ENOENT;
1018                                         goto err;
1019                                 }
1020                         }
1021
1022                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1023                         dirid = key.offset;
1024
1025                         inode_ref = btrfs_item_ptr(path->nodes[0],
1026                                                    path->slots[0],
1027                                                    struct btrfs_inode_ref);
1028                         len = btrfs_inode_ref_name_len(path->nodes[0],
1029                                                        inode_ref);
1030                         ptr -= len + 1;
1031                         if (ptr < name) {
1032                                 ret = -ENAMETOOLONG;
1033                                 goto err;
1034                         }
1035                         read_extent_buffer(path->nodes[0], ptr + 1,
1036                                            (unsigned long)(inode_ref + 1), len);
1037                         ptr[0] = '/';
1038                         btrfs_release_path(path);
1039                 }
1040         }
1041
1042         btrfs_free_path(path);
1043         if (ptr == name + PATH_MAX - 1) {
1044                 name[0] = '/';
1045                 name[1] = '\0';
1046         } else {
1047                 memmove(name, ptr, name + PATH_MAX - ptr);
1048         }
1049         return name;
1050
1051 err:
1052         btrfs_free_path(path);
1053         kfree(name);
1054         return ERR_PTR(ret);
1055 }
1056
1057 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1058 {
1059         struct btrfs_root *root = fs_info->tree_root;
1060         struct btrfs_dir_item *di;
1061         struct btrfs_path *path;
1062         struct btrfs_key location;
1063         u64 dir_id;
1064
1065         path = btrfs_alloc_path();
1066         if (!path)
1067                 return -ENOMEM;
1068         path->leave_spinning = 1;
1069
1070         /*
1071          * Find the "default" dir item which points to the root item that we
1072          * will mount by default if we haven't been given a specific subvolume
1073          * to mount.
1074          */
1075         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1076         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1077         if (IS_ERR(di)) {
1078                 btrfs_free_path(path);
1079                 return PTR_ERR(di);
1080         }
1081         if (!di) {
1082                 /*
1083                  * Ok the default dir item isn't there.  This is weird since
1084                  * it's always been there, but don't freak out, just try and
1085                  * mount the top-level subvolume.
1086                  */
1087                 btrfs_free_path(path);
1088                 *objectid = BTRFS_FS_TREE_OBJECTID;
1089                 return 0;
1090         }
1091
1092         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1093         btrfs_free_path(path);
1094         *objectid = location.objectid;
1095         return 0;
1096 }
1097
1098 static int btrfs_fill_super(struct super_block *sb,
1099                             struct btrfs_fs_devices *fs_devices,
1100                             void *data, int silent)
1101 {
1102         struct inode *inode;
1103         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1104         struct btrfs_key key;
1105         int err;
1106
1107         sb->s_maxbytes = MAX_LFS_FILESIZE;
1108         sb->s_magic = BTRFS_SUPER_MAGIC;
1109         sb->s_op = &btrfs_super_ops;
1110         sb->s_d_op = &btrfs_dentry_operations;
1111         sb->s_export_op = &btrfs_export_ops;
1112         sb->s_xattr = btrfs_xattr_handlers;
1113         sb->s_time_gran = 1;
1114 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1115         sb->s_flags |= MS_POSIXACL;
1116 #endif
1117         sb->s_flags |= MS_I_VERSION;
1118         sb->s_iflags |= SB_I_CGROUPWB;
1119         err = open_ctree(sb, fs_devices, (char *)data);
1120         if (err) {
1121                 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1122                 return err;
1123         }
1124
1125         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1126         key.type = BTRFS_INODE_ITEM_KEY;
1127         key.offset = 0;
1128         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1129         if (IS_ERR(inode)) {
1130                 err = PTR_ERR(inode);
1131                 goto fail_close;
1132         }
1133
1134         sb->s_root = d_make_root(inode);
1135         if (!sb->s_root) {
1136                 err = -ENOMEM;
1137                 goto fail_close;
1138         }
1139
1140         save_mount_options(sb, data);
1141         cleancache_init_fs(sb);
1142         sb->s_flags |= MS_ACTIVE;
1143         return 0;
1144
1145 fail_close:
1146         close_ctree(fs_info->tree_root);
1147         return err;
1148 }
1149
1150 int btrfs_sync_fs(struct super_block *sb, int wait)
1151 {
1152         struct btrfs_trans_handle *trans;
1153         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1154         struct btrfs_root *root = fs_info->tree_root;
1155
1156         trace_btrfs_sync_fs(wait);
1157
1158         if (!wait) {
1159                 filemap_flush(fs_info->btree_inode->i_mapping);
1160                 return 0;
1161         }
1162
1163         btrfs_wait_ordered_roots(fs_info, -1);
1164
1165         trans = btrfs_attach_transaction_barrier(root);
1166         if (IS_ERR(trans)) {
1167                 /* no transaction, don't bother */
1168                 if (PTR_ERR(trans) == -ENOENT) {
1169                         /*
1170                          * Exit unless we have some pending changes
1171                          * that need to go through commit
1172                          */
1173                         if (fs_info->pending_changes == 0)
1174                                 return 0;
1175                         /*
1176                          * A non-blocking test if the fs is frozen. We must not
1177                          * start a new transaction here otherwise a deadlock
1178                          * happens. The pending operations are delayed to the
1179                          * next commit after thawing.
1180                          */
1181                         if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1182                                 __sb_end_write(sb, SB_FREEZE_WRITE);
1183                         else
1184                                 return 0;
1185                         trans = btrfs_start_transaction(root, 0);
1186                 }
1187                 if (IS_ERR(trans))
1188                         return PTR_ERR(trans);
1189         }
1190         return btrfs_commit_transaction(trans, root);
1191 }
1192
1193 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1194 {
1195         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1196         struct btrfs_root *root = info->tree_root;
1197         char *compress_type;
1198
1199         if (btrfs_test_opt(root, DEGRADED))
1200                 seq_puts(seq, ",degraded");
1201         if (btrfs_test_opt(root, NODATASUM))
1202                 seq_puts(seq, ",nodatasum");
1203         if (btrfs_test_opt(root, NODATACOW))
1204                 seq_puts(seq, ",nodatacow");
1205         if (btrfs_test_opt(root, NOBARRIER))
1206                 seq_puts(seq, ",nobarrier");
1207         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1208                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1209         if (info->alloc_start != 0)
1210                 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1211         if (info->thread_pool_size !=  min_t(unsigned long,
1212                                              num_online_cpus() + 2, 8))
1213                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1214         if (btrfs_test_opt(root, COMPRESS)) {
1215                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1216                         compress_type = "zlib";
1217                 else
1218                         compress_type = "lzo";
1219                 if (btrfs_test_opt(root, FORCE_COMPRESS))
1220                         seq_printf(seq, ",compress-force=%s", compress_type);
1221                 else
1222                         seq_printf(seq, ",compress=%s", compress_type);
1223         }
1224         if (btrfs_test_opt(root, NOSSD))
1225                 seq_puts(seq, ",nossd");
1226         if (btrfs_test_opt(root, SSD_SPREAD))
1227                 seq_puts(seq, ",ssd_spread");
1228         else if (btrfs_test_opt(root, SSD))
1229                 seq_puts(seq, ",ssd");
1230         if (btrfs_test_opt(root, NOTREELOG))
1231                 seq_puts(seq, ",notreelog");
1232         if (btrfs_test_opt(root, NOLOGREPLAY))
1233                 seq_puts(seq, ",nologreplay");
1234         if (btrfs_test_opt(root, FLUSHONCOMMIT))
1235                 seq_puts(seq, ",flushoncommit");
1236         if (btrfs_test_opt(root, DISCARD))
1237                 seq_puts(seq, ",discard");
1238         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1239                 seq_puts(seq, ",noacl");
1240         if (btrfs_test_opt(root, SPACE_CACHE))
1241                 seq_puts(seq, ",space_cache");
1242         else if (btrfs_test_opt(root, FREE_SPACE_TREE))
1243                 seq_puts(seq, ",space_cache=v2");
1244         else
1245                 seq_puts(seq, ",nospace_cache");
1246         if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1247                 seq_puts(seq, ",rescan_uuid_tree");
1248         if (btrfs_test_opt(root, CLEAR_CACHE))
1249                 seq_puts(seq, ",clear_cache");
1250         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1251                 seq_puts(seq, ",user_subvol_rm_allowed");
1252         if (btrfs_test_opt(root, ENOSPC_DEBUG))
1253                 seq_puts(seq, ",enospc_debug");
1254         if (btrfs_test_opt(root, AUTO_DEFRAG))
1255                 seq_puts(seq, ",autodefrag");
1256         if (btrfs_test_opt(root, INODE_MAP_CACHE))
1257                 seq_puts(seq, ",inode_cache");
1258         if (btrfs_test_opt(root, SKIP_BALANCE))
1259                 seq_puts(seq, ",skip_balance");
1260 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1261         if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1262                 seq_puts(seq, ",check_int_data");
1263         else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1264                 seq_puts(seq, ",check_int");
1265         if (info->check_integrity_print_mask)
1266                 seq_printf(seq, ",check_int_print_mask=%d",
1267                                 info->check_integrity_print_mask);
1268 #endif
1269         if (info->metadata_ratio)
1270                 seq_printf(seq, ",metadata_ratio=%d",
1271                                 info->metadata_ratio);
1272         if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1273                 seq_puts(seq, ",fatal_errors=panic");
1274         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1275                 seq_printf(seq, ",commit=%d", info->commit_interval);
1276 #ifdef CONFIG_BTRFS_DEBUG
1277         if (btrfs_test_opt(root, FRAGMENT_DATA))
1278                 seq_puts(seq, ",fragment=data");
1279         if (btrfs_test_opt(root, FRAGMENT_METADATA))
1280                 seq_puts(seq, ",fragment=metadata");
1281 #endif
1282         seq_printf(seq, ",subvolid=%llu",
1283                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1284         seq_puts(seq, ",subvol=");
1285         seq_dentry(seq, dentry, " \t\n\\");
1286         return 0;
1287 }
1288
1289 static int btrfs_test_super(struct super_block *s, void *data)
1290 {
1291         struct btrfs_fs_info *p = data;
1292         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1293
1294         return fs_info->fs_devices == p->fs_devices;
1295 }
1296
1297 static int btrfs_set_super(struct super_block *s, void *data)
1298 {
1299         int err = set_anon_super(s, data);
1300         if (!err)
1301                 s->s_fs_info = data;
1302         return err;
1303 }
1304
1305 /*
1306  * subvolumes are identified by ino 256
1307  */
1308 static inline int is_subvolume_inode(struct inode *inode)
1309 {
1310         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1311                 return 1;
1312         return 0;
1313 }
1314
1315 /*
1316  * This will add subvolid=0 to the argument string while removing any subvol=
1317  * and subvolid= arguments to make sure we get the top-level root for path
1318  * walking to the subvol we want.
1319  */
1320 static char *setup_root_args(char *args)
1321 {
1322         char *buf, *dst, *sep;
1323
1324         if (!args)
1325                 return kstrdup("subvolid=0", GFP_NOFS);
1326
1327         /* The worst case is that we add ",subvolid=0" to the end. */
1328         buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1329         if (!buf)
1330                 return NULL;
1331
1332         while (1) {
1333                 sep = strchrnul(args, ',');
1334                 if (!strstarts(args, "subvol=") &&
1335                     !strstarts(args, "subvolid=")) {
1336                         memcpy(dst, args, sep - args);
1337                         dst += sep - args;
1338                         *dst++ = ',';
1339                 }
1340                 if (*sep)
1341                         args = sep + 1;
1342                 else
1343                         break;
1344         }
1345         strcpy(dst, "subvolid=0");
1346
1347         return buf;
1348 }
1349
1350 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1351                                    int flags, const char *device_name,
1352                                    char *data)
1353 {
1354         struct dentry *root;
1355         struct vfsmount *mnt = NULL;
1356         char *newargs;
1357         int ret;
1358
1359         newargs = setup_root_args(data);
1360         if (!newargs) {
1361                 root = ERR_PTR(-ENOMEM);
1362                 goto out;
1363         }
1364
1365         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1366         if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1367                 if (flags & MS_RDONLY) {
1368                         mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1369                                              device_name, newargs);
1370                 } else {
1371                         mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1372                                              device_name, newargs);
1373                         if (IS_ERR(mnt)) {
1374                                 root = ERR_CAST(mnt);
1375                                 mnt = NULL;
1376                                 goto out;
1377                         }
1378
1379                         down_write(&mnt->mnt_sb->s_umount);
1380                         ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1381                         up_write(&mnt->mnt_sb->s_umount);
1382                         if (ret < 0) {
1383                                 root = ERR_PTR(ret);
1384                                 goto out;
1385                         }
1386                 }
1387         }
1388         if (IS_ERR(mnt)) {
1389                 root = ERR_CAST(mnt);
1390                 mnt = NULL;
1391                 goto out;
1392         }
1393
1394         if (!subvol_name) {
1395                 if (!subvol_objectid) {
1396                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1397                                                           &subvol_objectid);
1398                         if (ret) {
1399                                 root = ERR_PTR(ret);
1400                                 goto out;
1401                         }
1402                 }
1403                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1404                                                             subvol_objectid);
1405                 if (IS_ERR(subvol_name)) {
1406                         root = ERR_CAST(subvol_name);
1407                         subvol_name = NULL;
1408                         goto out;
1409                 }
1410
1411         }
1412
1413         root = mount_subtree(mnt, subvol_name);
1414         /* mount_subtree() drops our reference on the vfsmount. */
1415         mnt = NULL;
1416
1417         if (!IS_ERR(root)) {
1418                 struct super_block *s = root->d_sb;
1419                 struct inode *root_inode = d_inode(root);
1420                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1421
1422                 ret = 0;
1423                 if (!is_subvolume_inode(root_inode)) {
1424                         pr_err("BTRFS: '%s' is not a valid subvolume\n",
1425                                subvol_name);
1426                         ret = -EINVAL;
1427                 }
1428                 if (subvol_objectid && root_objectid != subvol_objectid) {
1429                         /*
1430                          * This will also catch a race condition where a
1431                          * subvolume which was passed by ID is renamed and
1432                          * another subvolume is renamed over the old location.
1433                          */
1434                         pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1435                                subvol_name, subvol_objectid);
1436                         ret = -EINVAL;
1437                 }
1438                 if (ret) {
1439                         dput(root);
1440                         root = ERR_PTR(ret);
1441                         deactivate_locked_super(s);
1442                 }
1443         }
1444
1445 out:
1446         mntput(mnt);
1447         kfree(newargs);
1448         kfree(subvol_name);
1449         return root;
1450 }
1451
1452 static int parse_security_options(char *orig_opts,
1453                                   struct security_mnt_opts *sec_opts)
1454 {
1455         char *secdata = NULL;
1456         int ret = 0;
1457
1458         secdata = alloc_secdata();
1459         if (!secdata)
1460                 return -ENOMEM;
1461         ret = security_sb_copy_data(orig_opts, secdata);
1462         if (ret) {
1463                 free_secdata(secdata);
1464                 return ret;
1465         }
1466         ret = security_sb_parse_opts_str(secdata, sec_opts);
1467         free_secdata(secdata);
1468         return ret;
1469 }
1470
1471 static int setup_security_options(struct btrfs_fs_info *fs_info,
1472                                   struct super_block *sb,
1473                                   struct security_mnt_opts *sec_opts)
1474 {
1475         int ret = 0;
1476
1477         /*
1478          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1479          * is valid.
1480          */
1481         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1482         if (ret)
1483                 return ret;
1484
1485 #ifdef CONFIG_SECURITY
1486         if (!fs_info->security_opts.num_mnt_opts) {
1487                 /* first time security setup, copy sec_opts to fs_info */
1488                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1489         } else {
1490                 /*
1491                  * Since SELinux(the only one supports security_mnt_opts) does
1492                  * NOT support changing context during remount/mount same sb,
1493                  * This must be the same or part of the same security options,
1494                  * just free it.
1495                  */
1496                 security_free_mnt_opts(sec_opts);
1497         }
1498 #endif
1499         return ret;
1500 }
1501
1502 /*
1503  * Find a superblock for the given device / mount point.
1504  *
1505  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1506  *        for multiple device setup.  Make sure to keep it in sync.
1507  */
1508 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1509                 const char *device_name, void *data)
1510 {
1511         struct block_device *bdev = NULL;
1512         struct super_block *s;
1513         struct btrfs_fs_devices *fs_devices = NULL;
1514         struct btrfs_fs_info *fs_info = NULL;
1515         struct security_mnt_opts new_sec_opts;
1516         fmode_t mode = FMODE_READ;
1517         char *subvol_name = NULL;
1518         u64 subvol_objectid = 0;
1519         int error = 0;
1520
1521         if (!(flags & MS_RDONLY))
1522                 mode |= FMODE_WRITE;
1523
1524         error = btrfs_parse_early_options(data, mode, fs_type,
1525                                           &subvol_name, &subvol_objectid,
1526                                           &fs_devices);
1527         if (error) {
1528                 kfree(subvol_name);
1529                 return ERR_PTR(error);
1530         }
1531
1532         if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1533                 /* mount_subvol() will free subvol_name. */
1534                 return mount_subvol(subvol_name, subvol_objectid, flags,
1535                                     device_name, data);
1536         }
1537
1538         security_init_mnt_opts(&new_sec_opts);
1539         if (data) {
1540                 error = parse_security_options(data, &new_sec_opts);
1541                 if (error)
1542                         return ERR_PTR(error);
1543         }
1544
1545         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1546         if (error)
1547                 goto error_sec_opts;
1548
1549         /*
1550          * Setup a dummy root and fs_info for test/set super.  This is because
1551          * we don't actually fill this stuff out until open_ctree, but we need
1552          * it for searching for existing supers, so this lets us do that and
1553          * then open_ctree will properly initialize everything later.
1554          */
1555         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1556         if (!fs_info) {
1557                 error = -ENOMEM;
1558                 goto error_sec_opts;
1559         }
1560
1561         fs_info->fs_devices = fs_devices;
1562
1563         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1564         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1565         security_init_mnt_opts(&fs_info->security_opts);
1566         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1567                 error = -ENOMEM;
1568                 goto error_fs_info;
1569         }
1570
1571         error = btrfs_open_devices(fs_devices, mode, fs_type);
1572         if (error)
1573                 goto error_fs_info;
1574
1575         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1576                 error = -EACCES;
1577                 goto error_close_devices;
1578         }
1579
1580         bdev = fs_devices->latest_bdev;
1581         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1582                  fs_info);
1583         if (IS_ERR(s)) {
1584                 error = PTR_ERR(s);
1585                 goto error_close_devices;
1586         }
1587
1588         if (s->s_root) {
1589                 btrfs_close_devices(fs_devices);
1590                 free_fs_info(fs_info);
1591                 if ((flags ^ s->s_flags) & MS_RDONLY)
1592                         error = -EBUSY;
1593         } else {
1594                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1595                 btrfs_sb(s)->bdev_holder = fs_type;
1596                 error = btrfs_fill_super(s, fs_devices, data,
1597                                          flags & MS_SILENT ? 1 : 0);
1598         }
1599         if (error) {
1600                 deactivate_locked_super(s);
1601                 goto error_sec_opts;
1602         }
1603
1604         fs_info = btrfs_sb(s);
1605         error = setup_security_options(fs_info, s, &new_sec_opts);
1606         if (error) {
1607                 deactivate_locked_super(s);
1608                 goto error_sec_opts;
1609         }
1610
1611         return dget(s->s_root);
1612
1613 error_close_devices:
1614         btrfs_close_devices(fs_devices);
1615 error_fs_info:
1616         free_fs_info(fs_info);
1617 error_sec_opts:
1618         security_free_mnt_opts(&new_sec_opts);
1619         return ERR_PTR(error);
1620 }
1621
1622 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1623                                      int new_pool_size, int old_pool_size)
1624 {
1625         if (new_pool_size == old_pool_size)
1626                 return;
1627
1628         fs_info->thread_pool_size = new_pool_size;
1629
1630         btrfs_info(fs_info, "resize thread pool %d -> %d",
1631                old_pool_size, new_pool_size);
1632
1633         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1634         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1635         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1636         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1637         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1638         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1639         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1640                                 new_pool_size);
1641         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1642         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1643         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1644         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1645         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1646                                 new_pool_size);
1647 }
1648
1649 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1650 {
1651         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1652 }
1653
1654 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1655                                        unsigned long old_opts, int flags)
1656 {
1657         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1658             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1659              (flags & MS_RDONLY))) {
1660                 /* wait for any defraggers to finish */
1661                 wait_event(fs_info->transaction_wait,
1662                            (atomic_read(&fs_info->defrag_running) == 0));
1663                 if (flags & MS_RDONLY)
1664                         sync_filesystem(fs_info->sb);
1665         }
1666 }
1667
1668 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1669                                          unsigned long old_opts)
1670 {
1671         /*
1672          * We need cleanup all defragable inodes if the autodefragment is
1673          * close or the fs is R/O.
1674          */
1675         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1676             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1677              (fs_info->sb->s_flags & MS_RDONLY))) {
1678                 btrfs_cleanup_defrag_inodes(fs_info);
1679         }
1680
1681         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1682 }
1683
1684 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1685 {
1686         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1687         struct btrfs_root *root = fs_info->tree_root;
1688         unsigned old_flags = sb->s_flags;
1689         unsigned long old_opts = fs_info->mount_opt;
1690         unsigned long old_compress_type = fs_info->compress_type;
1691         u64 old_max_inline = fs_info->max_inline;
1692         u64 old_alloc_start = fs_info->alloc_start;
1693         int old_thread_pool_size = fs_info->thread_pool_size;
1694         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1695         int ret;
1696
1697         sync_filesystem(sb);
1698         btrfs_remount_prepare(fs_info);
1699
1700         if (data) {
1701                 struct security_mnt_opts new_sec_opts;
1702
1703                 security_init_mnt_opts(&new_sec_opts);
1704                 ret = parse_security_options(data, &new_sec_opts);
1705                 if (ret)
1706                         goto restore;
1707                 ret = setup_security_options(fs_info, sb,
1708                                              &new_sec_opts);
1709                 if (ret) {
1710                         security_free_mnt_opts(&new_sec_opts);
1711                         goto restore;
1712                 }
1713         }
1714
1715         ret = btrfs_parse_options(root, data, *flags);
1716         if (ret) {
1717                 ret = -EINVAL;
1718                 goto restore;
1719         }
1720
1721         btrfs_remount_begin(fs_info, old_opts, *flags);
1722         btrfs_resize_thread_pool(fs_info,
1723                 fs_info->thread_pool_size, old_thread_pool_size);
1724
1725         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1726                 goto out;
1727
1728         if (*flags & MS_RDONLY) {
1729                 /*
1730                  * this also happens on 'umount -rf' or on shutdown, when
1731                  * the filesystem is busy.
1732                  */
1733                 cancel_work_sync(&fs_info->async_reclaim_work);
1734
1735                 /* wait for the uuid_scan task to finish */
1736                 down(&fs_info->uuid_tree_rescan_sem);
1737                 /* avoid complains from lockdep et al. */
1738                 up(&fs_info->uuid_tree_rescan_sem);
1739
1740                 sb->s_flags |= MS_RDONLY;
1741
1742                 /*
1743                  * Setting MS_RDONLY will put the cleaner thread to
1744                  * sleep at the next loop if it's already active.
1745                  * If it's already asleep, we'll leave unused block
1746                  * groups on disk until we're mounted read-write again
1747                  * unless we clean them up here.
1748                  */
1749                 btrfs_delete_unused_bgs(fs_info);
1750
1751                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1752                 btrfs_scrub_cancel(fs_info);
1753                 btrfs_pause_balance(fs_info);
1754
1755                 ret = btrfs_commit_super(root);
1756                 if (ret)
1757                         goto restore;
1758         } else {
1759                 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1760                         btrfs_err(fs_info,
1761                                 "Remounting read-write after error is not allowed");
1762                         ret = -EINVAL;
1763                         goto restore;
1764                 }
1765                 if (fs_info->fs_devices->rw_devices == 0) {
1766                         ret = -EACCES;
1767                         goto restore;
1768                 }
1769
1770                 if (fs_info->fs_devices->missing_devices >
1771                      fs_info->num_tolerated_disk_barrier_failures &&
1772                     !(*flags & MS_RDONLY)) {
1773                         btrfs_warn(fs_info,
1774                                 "too many missing devices, writeable remount is not allowed");
1775                         ret = -EACCES;
1776                         goto restore;
1777                 }
1778
1779                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1780                         ret = -EINVAL;
1781                         goto restore;
1782                 }
1783
1784                 ret = btrfs_cleanup_fs_roots(fs_info);
1785                 if (ret)
1786                         goto restore;
1787
1788                 /* recover relocation */
1789                 mutex_lock(&fs_info->cleaner_mutex);
1790                 ret = btrfs_recover_relocation(root);
1791                 mutex_unlock(&fs_info->cleaner_mutex);
1792                 if (ret)
1793                         goto restore;
1794
1795                 ret = btrfs_resume_balance_async(fs_info);
1796                 if (ret)
1797                         goto restore;
1798
1799                 ret = btrfs_resume_dev_replace_async(fs_info);
1800                 if (ret) {
1801                         btrfs_warn(fs_info, "failed to resume dev_replace");
1802                         goto restore;
1803                 }
1804
1805                 if (!fs_info->uuid_root) {
1806                         btrfs_info(fs_info, "creating UUID tree");
1807                         ret = btrfs_create_uuid_tree(fs_info);
1808                         if (ret) {
1809                                 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1810                                 goto restore;
1811                         }
1812                 }
1813                 sb->s_flags &= ~MS_RDONLY;
1814         }
1815 out:
1816         wake_up_process(fs_info->transaction_kthread);
1817         btrfs_remount_cleanup(fs_info, old_opts);
1818         return 0;
1819
1820 restore:
1821         /* We've hit an error - don't reset MS_RDONLY */
1822         if (sb->s_flags & MS_RDONLY)
1823                 old_flags |= MS_RDONLY;
1824         sb->s_flags = old_flags;
1825         fs_info->mount_opt = old_opts;
1826         fs_info->compress_type = old_compress_type;
1827         fs_info->max_inline = old_max_inline;
1828         mutex_lock(&fs_info->chunk_mutex);
1829         fs_info->alloc_start = old_alloc_start;
1830         mutex_unlock(&fs_info->chunk_mutex);
1831         btrfs_resize_thread_pool(fs_info,
1832                 old_thread_pool_size, fs_info->thread_pool_size);
1833         fs_info->metadata_ratio = old_metadata_ratio;
1834         btrfs_remount_cleanup(fs_info, old_opts);
1835         return ret;
1836 }
1837
1838 /* Used to sort the devices by max_avail(descending sort) */
1839 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1840                                        const void *dev_info2)
1841 {
1842         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1843             ((struct btrfs_device_info *)dev_info2)->max_avail)
1844                 return -1;
1845         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1846                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1847                 return 1;
1848         else
1849         return 0;
1850 }
1851
1852 /*
1853  * sort the devices by max_avail, in which max free extent size of each device
1854  * is stored.(Descending Sort)
1855  */
1856 static inline void btrfs_descending_sort_devices(
1857                                         struct btrfs_device_info *devices,
1858                                         size_t nr_devices)
1859 {
1860         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1861              btrfs_cmp_device_free_bytes, NULL);
1862 }
1863
1864 /*
1865  * The helper to calc the free space on the devices that can be used to store
1866  * file data.
1867  */
1868 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1869 {
1870         struct btrfs_fs_info *fs_info = root->fs_info;
1871         struct btrfs_device_info *devices_info;
1872         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1873         struct btrfs_device *device;
1874         u64 skip_space;
1875         u64 type;
1876         u64 avail_space;
1877         u64 used_space;
1878         u64 min_stripe_size;
1879         int min_stripes = 1, num_stripes = 1;
1880         int i = 0, nr_devices;
1881         int ret;
1882
1883         /*
1884          * We aren't under the device list lock, so this is racey-ish, but good
1885          * enough for our purposes.
1886          */
1887         nr_devices = fs_info->fs_devices->open_devices;
1888         if (!nr_devices) {
1889                 smp_mb();
1890                 nr_devices = fs_info->fs_devices->open_devices;
1891                 ASSERT(nr_devices);
1892                 if (!nr_devices) {
1893                         *free_bytes = 0;
1894                         return 0;
1895                 }
1896         }
1897
1898         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1899                                GFP_NOFS);
1900         if (!devices_info)
1901                 return -ENOMEM;
1902
1903         /* calc min stripe number for data space alloction */
1904         type = btrfs_get_alloc_profile(root, 1);
1905         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1906                 min_stripes = 2;
1907                 num_stripes = nr_devices;
1908         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1909                 min_stripes = 2;
1910                 num_stripes = 2;
1911         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1912                 min_stripes = 4;
1913                 num_stripes = 4;
1914         }
1915
1916         if (type & BTRFS_BLOCK_GROUP_DUP)
1917                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1918         else
1919                 min_stripe_size = BTRFS_STRIPE_LEN;
1920
1921         if (fs_info->alloc_start)
1922                 mutex_lock(&fs_devices->device_list_mutex);
1923         rcu_read_lock();
1924         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1925                 if (!device->in_fs_metadata || !device->bdev ||
1926                     device->is_tgtdev_for_dev_replace)
1927                         continue;
1928
1929                 if (i >= nr_devices)
1930                         break;
1931
1932                 avail_space = device->total_bytes - device->bytes_used;
1933
1934                 /* align with stripe_len */
1935                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1936                 avail_space *= BTRFS_STRIPE_LEN;
1937
1938                 /*
1939                  * In order to avoid overwritting the superblock on the drive,
1940                  * btrfs starts at an offset of at least 1MB when doing chunk
1941                  * allocation.
1942                  */
1943                 skip_space = SZ_1M;
1944
1945                 /* user can set the offset in fs_info->alloc_start. */
1946                 if (fs_info->alloc_start &&
1947                     fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1948                     device->total_bytes) {
1949                         rcu_read_unlock();
1950                         skip_space = max(fs_info->alloc_start, skip_space);
1951
1952                         /*
1953                          * btrfs can not use the free space in
1954                          * [0, skip_space - 1], we must subtract it from the
1955                          * total. In order to implement it, we account the used
1956                          * space in this range first.
1957                          */
1958                         ret = btrfs_account_dev_extents_size(device, 0,
1959                                                              skip_space - 1,
1960                                                              &used_space);
1961                         if (ret) {
1962                                 kfree(devices_info);
1963                                 mutex_unlock(&fs_devices->device_list_mutex);
1964                                 return ret;
1965                         }
1966
1967                         rcu_read_lock();
1968
1969                         /* calc the free space in [0, skip_space - 1] */
1970                         skip_space -= used_space;
1971                 }
1972
1973                 /*
1974                  * we can use the free space in [0, skip_space - 1], subtract
1975                  * it from the total.
1976                  */
1977                 if (avail_space && avail_space >= skip_space)
1978                         avail_space -= skip_space;
1979                 else
1980                         avail_space = 0;
1981
1982                 if (avail_space < min_stripe_size)
1983                         continue;
1984
1985                 devices_info[i].dev = device;
1986                 devices_info[i].max_avail = avail_space;
1987
1988                 i++;
1989         }
1990         rcu_read_unlock();
1991         if (fs_info->alloc_start)
1992                 mutex_unlock(&fs_devices->device_list_mutex);
1993
1994         nr_devices = i;
1995
1996         btrfs_descending_sort_devices(devices_info, nr_devices);
1997
1998         i = nr_devices - 1;
1999         avail_space = 0;
2000         while (nr_devices >= min_stripes) {
2001                 if (num_stripes > nr_devices)
2002                         num_stripes = nr_devices;
2003
2004                 if (devices_info[i].max_avail >= min_stripe_size) {
2005                         int j;
2006                         u64 alloc_size;
2007
2008                         avail_space += devices_info[i].max_avail * num_stripes;
2009                         alloc_size = devices_info[i].max_avail;
2010                         for (j = i + 1 - num_stripes; j <= i; j++)
2011                                 devices_info[j].max_avail -= alloc_size;
2012                 }
2013                 i--;
2014                 nr_devices--;
2015         }
2016
2017         kfree(devices_info);
2018         *free_bytes = avail_space;
2019         return 0;
2020 }
2021
2022 /*
2023  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2024  *
2025  * If there's a redundant raid level at DATA block groups, use the respective
2026  * multiplier to scale the sizes.
2027  *
2028  * Unused device space usage is based on simulating the chunk allocator
2029  * algorithm that respects the device sizes, order of allocations and the
2030  * 'alloc_start' value, this is a close approximation of the actual use but
2031  * there are other factors that may change the result (like a new metadata
2032  * chunk).
2033  *
2034  * If metadata is exhausted, f_bavail will be 0.
2035  *
2036  * FIXME: not accurate for mixed block groups, total and free/used are ok,
2037  * available appears slightly larger.
2038  */
2039 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2040 {
2041         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2042         struct btrfs_super_block *disk_super = fs_info->super_copy;
2043         struct list_head *head = &fs_info->space_info;
2044         struct btrfs_space_info *found;
2045         u64 total_used = 0;
2046         u64 total_free_data = 0;
2047         u64 total_free_meta = 0;
2048         int bits = dentry->d_sb->s_blocksize_bits;
2049         __be32 *fsid = (__be32 *)fs_info->fsid;
2050         unsigned factor = 1;
2051         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2052         int ret;
2053         u64 thresh = 0;
2054
2055         /*
2056          * holding chunk_muext to avoid allocating new chunks, holding
2057          * device_list_mutex to avoid the device being removed
2058          */
2059         rcu_read_lock();
2060         list_for_each_entry_rcu(found, head, list) {
2061                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2062                         int i;
2063
2064                         total_free_data += found->disk_total - found->disk_used;
2065                         total_free_data -=
2066                                 btrfs_account_ro_block_groups_free_space(found);
2067
2068                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2069                                 if (!list_empty(&found->block_groups[i])) {
2070                                         switch (i) {
2071                                         case BTRFS_RAID_DUP:
2072                                         case BTRFS_RAID_RAID1:
2073                                         case BTRFS_RAID_RAID10:
2074                                                 factor = 2;
2075                                         }
2076                                 }
2077                         }
2078                 }
2079                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
2080                         total_free_meta += found->disk_total - found->disk_used;
2081
2082                 total_used += found->disk_used;
2083         }
2084
2085         rcu_read_unlock();
2086
2087         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2088         buf->f_blocks >>= bits;
2089         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2090
2091         /* Account global block reserve as used, it's in logical size already */
2092         spin_lock(&block_rsv->lock);
2093         buf->f_bfree -= block_rsv->size >> bits;
2094         spin_unlock(&block_rsv->lock);
2095
2096         buf->f_bavail = div_u64(total_free_data, factor);
2097         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2098         if (ret)
2099                 return ret;
2100         buf->f_bavail += div_u64(total_free_data, factor);
2101         buf->f_bavail = buf->f_bavail >> bits;
2102
2103         /*
2104          * We calculate the remaining metadata space minus global reserve. If
2105          * this is (supposedly) smaller than zero, there's no space. But this
2106          * does not hold in practice, the exhausted state happens where's still
2107          * some positive delta. So we apply some guesswork and compare the
2108          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2109          *
2110          * We probably cannot calculate the exact threshold value because this
2111          * depends on the internal reservations requested by various
2112          * operations, so some operations that consume a few metadata will
2113          * succeed even if the Avail is zero. But this is better than the other
2114          * way around.
2115          */
2116         thresh = 4 * 1024 * 1024;
2117
2118         if (total_free_meta - thresh < block_rsv->size)
2119                 buf->f_bavail = 0;
2120
2121         buf->f_type = BTRFS_SUPER_MAGIC;
2122         buf->f_bsize = dentry->d_sb->s_blocksize;
2123         buf->f_namelen = BTRFS_NAME_LEN;
2124
2125         /* We treat it as constant endianness (it doesn't matter _which_)
2126            because we want the fsid to come out the same whether mounted
2127            on a big-endian or little-endian host */
2128         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2129         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2130         /* Mask in the root object ID too, to disambiguate subvols */
2131         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2132         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2133
2134         return 0;
2135 }
2136
2137 static void btrfs_kill_super(struct super_block *sb)
2138 {
2139         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2140         kill_anon_super(sb);
2141         free_fs_info(fs_info);
2142 }
2143
2144 static struct file_system_type btrfs_fs_type = {
2145         .owner          = THIS_MODULE,
2146         .name           = "btrfs",
2147         .mount          = btrfs_mount,
2148         .kill_sb        = btrfs_kill_super,
2149         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2150 };
2151 MODULE_ALIAS_FS("btrfs");
2152
2153 static int btrfs_control_open(struct inode *inode, struct file *file)
2154 {
2155         /*
2156          * The control file's private_data is used to hold the
2157          * transaction when it is started and is used to keep
2158          * track of whether a transaction is already in progress.
2159          */
2160         file->private_data = NULL;
2161         return 0;
2162 }
2163
2164 /*
2165  * used by btrfsctl to scan devices when no FS is mounted
2166  */
2167 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2168                                 unsigned long arg)
2169 {
2170         struct btrfs_ioctl_vol_args *vol;
2171         struct btrfs_fs_devices *fs_devices;
2172         int ret = -ENOTTY;
2173
2174         if (!capable(CAP_SYS_ADMIN))
2175                 return -EPERM;
2176
2177         vol = memdup_user((void __user *)arg, sizeof(*vol));
2178         if (IS_ERR(vol))
2179                 return PTR_ERR(vol);
2180
2181         switch (cmd) {
2182         case BTRFS_IOC_SCAN_DEV:
2183                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2184                                             &btrfs_fs_type, &fs_devices);
2185                 break;
2186         case BTRFS_IOC_DEVICES_READY:
2187                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2188                                             &btrfs_fs_type, &fs_devices);
2189                 if (ret)
2190                         break;
2191                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2192                 break;
2193         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2194                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2195                 break;
2196         }
2197
2198         kfree(vol);
2199         return ret;
2200 }
2201
2202 static int btrfs_freeze(struct super_block *sb)
2203 {
2204         struct btrfs_trans_handle *trans;
2205         struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2206
2207         trans = btrfs_attach_transaction_barrier(root);
2208         if (IS_ERR(trans)) {
2209                 /* no transaction, don't bother */
2210                 if (PTR_ERR(trans) == -ENOENT)
2211                         return 0;
2212                 return PTR_ERR(trans);
2213         }
2214         return btrfs_commit_transaction(trans, root);
2215 }
2216
2217 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2218 {
2219         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2220         struct btrfs_fs_devices *cur_devices;
2221         struct btrfs_device *dev, *first_dev = NULL;
2222         struct list_head *head;
2223         struct rcu_string *name;
2224
2225         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2226         cur_devices = fs_info->fs_devices;
2227         while (cur_devices) {
2228                 head = &cur_devices->devices;
2229                 list_for_each_entry(dev, head, dev_list) {
2230                         if (dev->missing)
2231                                 continue;
2232                         if (!dev->name)
2233                                 continue;
2234                         if (!first_dev || dev->devid < first_dev->devid)
2235                                 first_dev = dev;
2236                 }
2237                 cur_devices = cur_devices->seed;
2238         }
2239
2240         if (first_dev) {
2241                 rcu_read_lock();
2242                 name = rcu_dereference(first_dev->name);
2243                 seq_escape(m, name->str, " \t\n\\");
2244                 rcu_read_unlock();
2245         } else {
2246                 WARN_ON(1);
2247         }
2248         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2249         return 0;
2250 }
2251
2252 static const struct super_operations btrfs_super_ops = {
2253         .drop_inode     = btrfs_drop_inode,
2254         .evict_inode    = btrfs_evict_inode,
2255         .put_super      = btrfs_put_super,
2256         .sync_fs        = btrfs_sync_fs,
2257         .show_options   = btrfs_show_options,
2258         .show_devname   = btrfs_show_devname,
2259         .write_inode    = btrfs_write_inode,
2260         .alloc_inode    = btrfs_alloc_inode,
2261         .destroy_inode  = btrfs_destroy_inode,
2262         .statfs         = btrfs_statfs,
2263         .remount_fs     = btrfs_remount,
2264         .freeze_fs      = btrfs_freeze,
2265 };
2266
2267 static const struct file_operations btrfs_ctl_fops = {
2268         .open = btrfs_control_open,
2269         .unlocked_ioctl  = btrfs_control_ioctl,
2270         .compat_ioctl = btrfs_control_ioctl,
2271         .owner   = THIS_MODULE,
2272         .llseek = noop_llseek,
2273 };
2274
2275 static struct miscdevice btrfs_misc = {
2276         .minor          = BTRFS_MINOR,
2277         .name           = "btrfs-control",
2278         .fops           = &btrfs_ctl_fops
2279 };
2280
2281 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2282 MODULE_ALIAS("devname:btrfs-control");
2283
2284 static int btrfs_interface_init(void)
2285 {
2286         return misc_register(&btrfs_misc);
2287 }
2288
2289 static void btrfs_interface_exit(void)
2290 {
2291         misc_deregister(&btrfs_misc);
2292 }
2293
2294 static void btrfs_print_mod_info(void)
2295 {
2296         printk(KERN_INFO "Btrfs loaded"
2297 #ifdef CONFIG_BTRFS_DEBUG
2298                         ", debug=on"
2299 #endif
2300 #ifdef CONFIG_BTRFS_ASSERT
2301                         ", assert=on"
2302 #endif
2303 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2304                         ", integrity-checker=on"
2305 #endif
2306                         "\n");
2307 }
2308
2309 static int btrfs_run_sanity_tests(void)
2310 {
2311         int ret;
2312
2313         ret = btrfs_init_test_fs();
2314         if (ret)
2315                 return ret;
2316
2317         ret = btrfs_test_free_space_cache();
2318         if (ret)
2319                 goto out;
2320         ret = btrfs_test_extent_buffer_operations();
2321         if (ret)
2322                 goto out;
2323         ret = btrfs_test_extent_io();
2324         if (ret)
2325                 goto out;
2326         ret = btrfs_test_inodes();
2327         if (ret)
2328                 goto out;
2329         ret = btrfs_test_qgroups();
2330         if (ret)
2331                 goto out;
2332         ret = btrfs_test_free_space_tree();
2333 out:
2334         btrfs_destroy_test_fs();
2335         return ret;
2336 }
2337
2338 static int __init init_btrfs_fs(void)
2339 {
2340         int err;
2341
2342         err = btrfs_hash_init();
2343         if (err)
2344                 return err;
2345
2346         btrfs_props_init();
2347
2348         err = btrfs_init_sysfs();
2349         if (err)
2350                 goto free_hash;
2351
2352         btrfs_init_compress();
2353
2354         err = btrfs_init_cachep();
2355         if (err)
2356                 goto free_compress;
2357
2358         err = extent_io_init();
2359         if (err)
2360                 goto free_cachep;
2361
2362         err = extent_map_init();
2363         if (err)
2364                 goto free_extent_io;
2365
2366         err = ordered_data_init();
2367         if (err)
2368                 goto free_extent_map;
2369
2370         err = btrfs_delayed_inode_init();
2371         if (err)
2372                 goto free_ordered_data;
2373
2374         err = btrfs_auto_defrag_init();
2375         if (err)
2376                 goto free_delayed_inode;
2377
2378         err = btrfs_delayed_ref_init();
2379         if (err)
2380                 goto free_auto_defrag;
2381
2382         err = btrfs_prelim_ref_init();
2383         if (err)
2384                 goto free_delayed_ref;
2385
2386         err = btrfs_end_io_wq_init();
2387         if (err)
2388                 goto free_prelim_ref;
2389
2390         err = btrfs_interface_init();
2391         if (err)
2392                 goto free_end_io_wq;
2393
2394         btrfs_init_lockdep();
2395
2396         btrfs_print_mod_info();
2397
2398         err = btrfs_run_sanity_tests();
2399         if (err)
2400                 goto unregister_ioctl;
2401
2402         err = register_filesystem(&btrfs_fs_type);
2403         if (err)
2404                 goto unregister_ioctl;
2405
2406         return 0;
2407
2408 unregister_ioctl:
2409         btrfs_interface_exit();
2410 free_end_io_wq:
2411         btrfs_end_io_wq_exit();
2412 free_prelim_ref:
2413         btrfs_prelim_ref_exit();
2414 free_delayed_ref:
2415         btrfs_delayed_ref_exit();
2416 free_auto_defrag:
2417         btrfs_auto_defrag_exit();
2418 free_delayed_inode:
2419         btrfs_delayed_inode_exit();
2420 free_ordered_data:
2421         ordered_data_exit();
2422 free_extent_map:
2423         extent_map_exit();
2424 free_extent_io:
2425         extent_io_exit();
2426 free_cachep:
2427         btrfs_destroy_cachep();
2428 free_compress:
2429         btrfs_exit_compress();
2430         btrfs_exit_sysfs();
2431 free_hash:
2432         btrfs_hash_exit();
2433         return err;
2434 }
2435
2436 static void __exit exit_btrfs_fs(void)
2437 {
2438         btrfs_destroy_cachep();
2439         btrfs_delayed_ref_exit();
2440         btrfs_auto_defrag_exit();
2441         btrfs_delayed_inode_exit();
2442         btrfs_prelim_ref_exit();
2443         ordered_data_exit();
2444         extent_map_exit();
2445         extent_io_exit();
2446         btrfs_interface_exit();
2447         btrfs_end_io_wq_exit();
2448         unregister_filesystem(&btrfs_fs_type);
2449         btrfs_exit_sysfs();
2450         btrfs_cleanup_fs_uuids();
2451         btrfs_exit_compress();
2452         btrfs_hash_exit();
2453 }
2454
2455 late_initcall(init_btrfs_fs);
2456 module_exit(exit_btrfs_fs)
2457
2458 MODULE_LICENSE("GPL");