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/mnt_namespace.h>
  44 #include <linux/ratelimit.h>
  45 #include "compat.h"
  46 #include "delayed-inode.h"
  47 #include "ctree.h"
  48 #include "disk-io.h"
  49 #include "transaction.h"
  50 #include "btrfs_inode.h"
  51 #include "ioctl.h"
  52 #include "print-tree.h"
  53 #include "xattr.h"
  54 #include "volumes.h"
  55 #include "version.h"
  56 #include "export.h"
  57 #include "compression.h"
  58
  59 #define CREATE_TRACE_POINTS
  60 #include <trace/events/btrfs.h>
  61
  62 static const struct super_operations btrfs_super_ops;
  63 static struct file_system_type btrfs_fs_type;
  64
  65 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
  66                                       char nbuf[16])
  67 {
  68         char *errstr = NULL;
  69
  70         switch (errno) {
  71         case -EIO:
  72                 errstr = "IO failure";
  73                 break;
  74         case -ENOMEM:
  75                 errstr = "Out of memory";
  76                 break;
  77         case -EROFS:
  78                 errstr = "Readonly filesystem";
  79                 break;
  80         default:
  81                 if (nbuf) {
  82                         if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
  83                                 errstr = nbuf;
  84                 }
  85                 break;
  86         }
  87
  88         return errstr;
  89 }
  90
  91 static void __save_error_info(struct btrfs_fs_info *fs_info)
  92 {
  93         /*
  94          * today we only save the error info into ram.  Long term we'll
  95          * also send it down to the disk
  96          */
  97         fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
  98 }
  99
 100 /* NOTE:
 101  *      We move write_super stuff at umount in order to avoid deadlock
 102  *      for umount hold all lock.
 103  */
 104 static void save_error_info(struct btrfs_fs_info *fs_info)
 105 {
 106         __save_error_info(fs_info);
 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 (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
 118                 sb->s_flags |= MS_RDONLY;
 119                 printk(KERN_INFO "btrfs is forced readonly\n");
 120         }
 121 }
 122
 123 /*
 124  * __btrfs_std_error decodes expected errors from the caller and
 125  * invokes the approciate error response.
 126  */
 127 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 128                      unsigned int line, int errno)
 129 {
 130         struct super_block *sb = fs_info->sb;
 131         char nbuf[16];
 132         const char *errstr;
 133
 134         /*
 135          * Special case: if the error is EROFS, and we're already
 136          * under MS_RDONLY, then it is safe here.
 137          */
 138         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 139                 return;
 140
 141         errstr = btrfs_decode_error(fs_info, errno, nbuf);
 142         printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
 143                 sb->s_id, function, line, errstr);
 144         save_error_info(fs_info);
 145
 146         btrfs_handle_error(fs_info);
 147 }
 148
 149 static void btrfs_put_super(struct super_block *sb)
 150 {
 151         struct btrfs_root *root = btrfs_sb(sb);
 152         int ret;
 153
 154         ret = close_ctree(root);
 155         sb->s_fs_info = NULL;
 156
 157         (void)ret; /* FIXME: need to fix VFS to return error? */
 158 }
 159
 160 enum {
 161         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 162         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 163         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 164         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 165         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 166         Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
 167         Opt_enospc_debug, Opt_subvolrootid, Opt_defrag,
 168         Opt_inode_cache, Opt_no_space_cache, Opt_recovery, Opt_err,
 169 };
 170
 171 static match_table_t tokens = {
 172         {Opt_degraded, "degraded"},
 173         {Opt_subvol, "subvol=%s"},
 174         {Opt_subvolid, "subvolid=%d"},
 175         {Opt_device, "device=%s"},
 176         {Opt_nodatasum, "nodatasum"},
 177         {Opt_nodatacow, "nodatacow"},
 178         {Opt_nobarrier, "nobarrier"},
 179         {Opt_max_inline, "max_inline=%s"},
 180         {Opt_alloc_start, "alloc_start=%s"},
 181         {Opt_thread_pool, "thread_pool=%d"},
 182         {Opt_compress, "compress"},
 183         {Opt_compress_type, "compress=%s"},
 184         {Opt_compress_force, "compress-force"},
 185         {Opt_compress_force_type, "compress-force=%s"},
 186         {Opt_ssd, "ssd"},
 187         {Opt_ssd_spread, "ssd_spread"},
 188         {Opt_nossd, "nossd"},
 189         {Opt_noacl, "noacl"},
 190         {Opt_notreelog, "notreelog"},
 191         {Opt_flushoncommit, "flushoncommit"},
 192         {Opt_ratio, "metadata_ratio=%d"},
 193         {Opt_discard, "discard"},
 194         {Opt_space_cache, "space_cache"},
 195         {Opt_clear_cache, "clear_cache"},
 196         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 197         {Opt_enospc_debug, "enospc_debug"},
 198         {Opt_subvolrootid, "subvolrootid=%d"},
 199         {Opt_defrag, "autodefrag"},
 200         {Opt_inode_cache, "inode_cache"},
 201         {Opt_no_space_cache, "nospace_cache"},
 202         {Opt_recovery, "recovery"},
 203         {Opt_err, NULL},
 204 };
 205
 206 /*
 207  * Regular mount options parser.  Everything that is needed only when
 208  * reading in a new superblock is parsed here.
 209  */
 210 int btrfs_parse_options(struct btrfs_root *root, char *options)
 211 {
 212         struct btrfs_fs_info *info = root->fs_info;
 213         substring_t args[MAX_OPT_ARGS];
 214         char *p, *num, *orig = NULL;
 215         u64 cache_gen;
 216         int intarg;
 217         int ret = 0;
 218         char *compress_type;
 219         bool compress_force = false;
 220
 221         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 222         if (cache_gen)
 223                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 224
 225         if (!options)
 226                 goto out;
 227
 228         /*
 229          * strsep changes the string, duplicate it because parse_options
 230          * gets called twice
 231          */
 232         options = kstrdup(options, GFP_NOFS);
 233         if (!options)
 234                 return -ENOMEM;
 235
 236         orig = options;
 237
 238         while ((p = strsep(&options, ",")) != NULL) {
 239                 int token;
 240                 if (!*p)
 241                         continue;
 242
 243                 token = match_token(p, tokens, args);
 244                 switch (token) {
 245                 case Opt_degraded:
 246                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 247                         btrfs_set_opt(info->mount_opt, DEGRADED);
 248                         break;
 249                 case Opt_subvol:
 250                 case Opt_subvolid:
 251                 case Opt_subvolrootid:
 252                 case Opt_device:
 253                         /*
 254                          * These are parsed by btrfs_parse_early_options
 255                          * and can be happily ignored here.
 256                          */
 257                         break;
 258                 case Opt_nodatasum:
 259                         printk(KERN_INFO "btrfs: setting nodatasum\n");
 260                         btrfs_set_opt(info->mount_opt, NODATASUM);
 261                         break;
 262                 case Opt_nodatacow:
 263                         printk(KERN_INFO "btrfs: setting nodatacow\n");
 264                         btrfs_set_opt(info->mount_opt, NODATACOW);
 265                         btrfs_set_opt(info->mount_opt, NODATASUM);
 266                         break;
 267                 case Opt_compress_force:
 268                 case Opt_compress_force_type:
 269                         compress_force = true;
 270                 case Opt_compress:
 271                 case Opt_compress_type:
 272                         if (token == Opt_compress ||
 273                             token == Opt_compress_force ||
 274                             strcmp(args[0].from, "zlib") == 0) {
 275                                 compress_type = "zlib";
 276                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 277                         } else if (strcmp(args[0].from, "lzo") == 0) {
 278                                 compress_type = "lzo";
 279                                 info->compress_type = BTRFS_COMPRESS_LZO;
 280                         } else {
 281                                 ret = -EINVAL;
 282                                 goto out;
 283                         }
 284
 285                         btrfs_set_opt(info->mount_opt, COMPRESS);
 286                         if (compress_force) {
 287                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 288                                 pr_info("btrfs: force %s compression\n",
 289                                         compress_type);
 290                         } else
 291                                 pr_info("btrfs: use %s compression\n",
 292                                         compress_type);
 293                         break;
 294                 case Opt_ssd:
 295                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 296                         btrfs_set_opt(info->mount_opt, SSD);
 297                         break;
 298                 case Opt_ssd_spread:
 299                         printk(KERN_INFO "btrfs: use spread ssd "
 300                                "allocation scheme\n");
 301                         btrfs_set_opt(info->mount_opt, SSD);
 302                         btrfs_set_opt(info->mount_opt, SSD_SPREAD);
 303                         break;
 304                 case Opt_nossd:
 305                         printk(KERN_INFO "btrfs: not using ssd allocation "
 306                                "scheme\n");
 307                         btrfs_set_opt(info->mount_opt, NOSSD);
 308                         btrfs_clear_opt(info->mount_opt, SSD);
 309                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
 310                         break;
 311                 case Opt_nobarrier:
 312                         printk(KERN_INFO "btrfs: turning off barriers\n");
 313                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 314                         break;
 315                 case Opt_thread_pool:
 316                         intarg = 0;
 317                         match_int(&args[0], &intarg);
 318                         if (intarg) {
 319                                 info->thread_pool_size = intarg;
 320                                 printk(KERN_INFO "btrfs: thread pool %d\n",
 321                                        info->thread_pool_size);
 322                         }
 323                         break;
 324                 case Opt_max_inline:
 325                         num = match_strdup(&args[0]);
 326                         if (num) {
 327                                 info->max_inline = memparse(num, NULL);
 328                                 kfree(num);
 329
 330                                 if (info->max_inline) {
 331                                         info->max_inline = max_t(u64,
 332                                                 info->max_inline,
 333                                                 root->sectorsize);
 334                                 }
 335                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 336                                         (unsigned long long)info->max_inline);
 337                         }
 338                         break;
 339                 case Opt_alloc_start:
 340                         num = match_strdup(&args[0]);
 341                         if (num) {
 342                                 info->alloc_start = memparse(num, NULL);
 343                                 kfree(num);
 344                                 printk(KERN_INFO
 345                                         "btrfs: allocations start at %llu\n",
 346                                         (unsigned long long)info->alloc_start);
 347                         }
 348                         break;
 349                 case Opt_noacl:
 350                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 351                         break;
 352                 case Opt_notreelog:
 353                         printk(KERN_INFO "btrfs: disabling tree log\n");
 354                         btrfs_set_opt(info->mount_opt, NOTREELOG);
 355                         break;
 356                 case Opt_flushoncommit:
 357                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
 358                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
 359                         break;
 360                 case Opt_ratio:
 361                         intarg = 0;
 362                         match_int(&args[0], &intarg);
 363                         if (intarg) {
 364                                 info->metadata_ratio = intarg;
 365                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
 366                                        info->metadata_ratio);
 367                         }
 368                         break;
 369                 case Opt_discard:
 370                         btrfs_set_opt(info->mount_opt, DISCARD);
 371                         break;
 372                 case Opt_space_cache:
 373                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 374                         break;
 375                 case Opt_no_space_cache:
 376                         printk(KERN_INFO "btrfs: disabling disk space caching\n");
 377                         btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
 378                         break;
 379                 case Opt_inode_cache:
 380                         printk(KERN_INFO "btrfs: enabling inode map caching\n");
 381                         btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
 382                         break;
 383                 case Opt_clear_cache:
 384                         printk(KERN_INFO "btrfs: force clearing of disk cache\n");
 385                         btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
 386                         break;
 387                 case Opt_user_subvol_rm_allowed:
 388                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 389                         break;
 390                 case Opt_enospc_debug:
 391                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 392                         break;
 393                 case Opt_defrag:
 394                         printk(KERN_INFO "btrfs: enabling auto defrag");
 395                         btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
 396                         break;
 397                 case Opt_recovery:
 398                         printk(KERN_INFO "btrfs: enabling auto recovery");
 399                         btrfs_set_opt(info->mount_opt, RECOVERY);
 400                         break;
 401                 case Opt_err:
 402                         printk(KERN_INFO "btrfs: unrecognized mount option "
 403                                "'%s'\n", p);
 404                         ret = -EINVAL;
 405                         goto out;
 406                 default:
 407                         break;
 408                 }
 409         }
 410 out:
 411         if (!ret && btrfs_test_opt(root, SPACE_CACHE))
 412                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
 413         kfree(orig);
 414         return ret;
 415 }
 416
 417 /*
 418  * Parse mount options that are required early in the mount process.
 419  *
 420  * All other options will be parsed on much later in the mount process and
 421  * only when we need to allocate a new super block.
 422  */
 423 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 424                 void *holder, char **subvol_name, u64 *subvol_objectid,
 425                 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
 426 {
 427         substring_t args[MAX_OPT_ARGS];
 428         char *device_name, *opts, *orig, *p;
 429         int error = 0;
 430         int intarg;
 431
 432         if (!options)
 433                 return 0;
 434
 435         /*
 436          * strsep changes the string, duplicate it because parse_options
 437          * gets called twice
 438          */
 439         opts = kstrdup(options, GFP_KERNEL);
 440         if (!opts)
 441                 return -ENOMEM;
 442         orig = opts;
 443
 444         while ((p = strsep(&opts, ",")) != NULL) {
 445                 int token;
 446                 if (!*p)
 447                         continue;
 448
 449                 token = match_token(p, tokens, args);
 450                 switch (token) {
 451                 case Opt_subvol:
 452                         kfree(*subvol_name);
 453                         *subvol_name = match_strdup(&args[0]);
 454                         break;
 455                 case Opt_subvolid:
 456                         intarg = 0;
 457                         error = match_int(&args[0], &intarg);
 458                         if (!error) {
 459                                 /* we want the original fs_tree */
 460                                 if (!intarg)
 461                                         *subvol_objectid =
 462                                                 BTRFS_FS_TREE_OBJECTID;
 463                                 else
 464                                         *subvol_objectid = intarg;
 465                         }
 466                         break;
 467                 case Opt_subvolrootid:
 468                         intarg = 0;
 469                         error = match_int(&args[0], &intarg);
 470                         if (!error) {
 471                                 /* we want the original fs_tree */
 472                                 if (!intarg)
 473                                         *subvol_rootid =
 474                                                 BTRFS_FS_TREE_OBJECTID;
 475                                 else
 476                                         *subvol_rootid = intarg;
 477                         }
 478                         break;
 479                 case Opt_device:
 480                         device_name = match_strdup(&args[0]);
 481                         if (!device_name) {
 482                                 error = -ENOMEM;
 483                                 goto out;
 484                         }
 485                         error = btrfs_scan_one_device(device_name,
 486                                         flags, holder, fs_devices);
 487                         kfree(device_name);
 488                         if (error)
 489                                 goto out;
 490                         break;
 491                 default:
 492                         break;
 493                 }
 494         }
 495
 496 out:
 497         kfree(orig);
 498         return error;
 499 }
 500
 501 static struct dentry *get_default_root(struct super_block *sb,
 502                                        u64 subvol_objectid)
 503 {
 504         struct btrfs_root *root = sb->s_fs_info;
 505         struct btrfs_root *new_root;
 506         struct btrfs_dir_item *di;
 507         struct btrfs_path *path;
 508         struct btrfs_key location;
 509         struct inode *inode;
 510         u64 dir_id;
 511         int new = 0;
 512
 513         /*
 514          * We have a specific subvol we want to mount, just setup location and
 515          * go look up the root.
 516          */
 517         if (subvol_objectid) {
 518                 location.objectid = subvol_objectid;
 519                 location.type = BTRFS_ROOT_ITEM_KEY;
 520                 location.offset = (u64)-1;
 521                 goto find_root;
 522         }
 523
 524         path = btrfs_alloc_path();
 525         if (!path)
 526                 return ERR_PTR(-ENOMEM);
 527         path->leave_spinning = 1;
 528
 529         /*
 530          * Find the "default" dir item which points to the root item that we
 531          * will mount by default if we haven't been given a specific subvolume
 532          * to mount.
 533          */
 534         dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
 535         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
 536         if (IS_ERR(di)) {
 537                 btrfs_free_path(path);
 538                 return ERR_CAST(di);
 539         }
 540         if (!di) {
 541                 /*
 542                  * Ok the default dir item isn't there.  This is weird since
 543                  * it's always been there, but don't freak out, just try and
 544                  * mount to root most subvolume.
 545                  */
 546                 btrfs_free_path(path);
 547                 dir_id = BTRFS_FIRST_FREE_OBJECTID;
 548                 new_root = root->fs_info->fs_root;
 549                 goto setup_root;
 550         }
 551
 552         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
 553         btrfs_free_path(path);
 554
 555 find_root:
 556         new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
 557         if (IS_ERR(new_root))
 558                 return ERR_CAST(new_root);
 559
 560         if (btrfs_root_refs(&new_root->root_item) == 0)
 561                 return ERR_PTR(-ENOENT);
 562
 563         dir_id = btrfs_root_dirid(&new_root->root_item);
 564 setup_root:
 565         location.objectid = dir_id;
 566         location.type = BTRFS_INODE_ITEM_KEY;
 567         location.offset = 0;
 568
 569         inode = btrfs_iget(sb, &location, new_root, &new);
 570         if (IS_ERR(inode))
 571                 return ERR_CAST(inode);
 572
 573         /*
 574          * If we're just mounting the root most subvol put the inode and return
 575          * a reference to the dentry.  We will have already gotten a reference
 576          * to the inode in btrfs_fill_super so we're good to go.
 577          */
 578         if (!new && sb->s_root->d_inode == inode) {
 579                 iput(inode);
 580                 return dget(sb->s_root);
 581         }
 582
 583         return d_obtain_alias(inode);
 584 }
 585
 586 static int btrfs_fill_super(struct super_block *sb,
 587                             struct btrfs_fs_devices *fs_devices,
 588                             void *data, int silent)
 589 {
 590         struct inode *inode;
 591         struct dentry *root_dentry;
 592         struct btrfs_root *tree_root;
 593         struct btrfs_key key;
 594         int err;
 595
 596         sb->s_maxbytes = MAX_LFS_FILESIZE;
 597         sb->s_magic = BTRFS_SUPER_MAGIC;
 598         sb->s_op = &btrfs_super_ops;
 599         sb->s_d_op = &btrfs_dentry_operations;
 600         sb->s_export_op = &btrfs_export_ops;
 601         sb->s_xattr = btrfs_xattr_handlers;
 602         sb->s_time_gran = 1;
 603 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 604         sb->s_flags |= MS_POSIXACL;
 605 #endif
 606
 607         tree_root = open_ctree(sb, fs_devices, (char *)data);
 608
 609         if (IS_ERR(tree_root)) {
 610                 printk("btrfs: open_ctree failed\n");
 611                 return PTR_ERR(tree_root);
 612         }
 613         sb->s_fs_info = tree_root;
 614
 615         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 616         key.type = BTRFS_INODE_ITEM_KEY;
 617         key.offset = 0;
 618         inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
 619         if (IS_ERR(inode)) {
 620                 err = PTR_ERR(inode);
 621                 goto fail_close;
 622         }
 623
 624         root_dentry = d_alloc_root(inode);
 625         if (!root_dentry) {
 626                 iput(inode);
 627                 err = -ENOMEM;
 628                 goto fail_close;
 629         }
 630
 631         sb->s_root = root_dentry;
 632
 633         save_mount_options(sb, data);
 634         cleancache_init_fs(sb);
 635         return 0;
 636
 637 fail_close:
 638         close_ctree(tree_root);
 639         return err;
 640 }
 641
 642 int btrfs_sync_fs(struct super_block *sb, int wait)
 643 {
 644         struct btrfs_trans_handle *trans;
 645         struct btrfs_root *root = btrfs_sb(sb);
 646         int ret;
 647
 648         trace_btrfs_sync_fs(wait);
 649
 650         if (!wait) {
 651                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 652                 return 0;
 653         }
 654
 655         btrfs_start_delalloc_inodes(root, 0);
 656         btrfs_wait_ordered_extents(root, 0, 0);
 657
 658         trans = btrfs_start_transaction(root, 0);
 659         if (IS_ERR(trans))
 660                 return PTR_ERR(trans);
 661         ret = btrfs_commit_transaction(trans, root);
 662         return ret;
 663 }
 664
 665 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 666 {
 667         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
 668         struct btrfs_fs_info *info = root->fs_info;
 669         char *compress_type;
 670
 671         if (btrfs_test_opt(root, DEGRADED))
 672                 seq_puts(seq, ",degraded");
 673         if (btrfs_test_opt(root, NODATASUM))
 674                 seq_puts(seq, ",nodatasum");
 675         if (btrfs_test_opt(root, NODATACOW))
 676                 seq_puts(seq, ",nodatacow");
 677         if (btrfs_test_opt(root, NOBARRIER))
 678                 seq_puts(seq, ",nobarrier");
 679         if (info->max_inline != 8192 * 1024)
 680                 seq_printf(seq, ",max_inline=%llu",
 681                            (unsigned long long)info->max_inline);
 682         if (info->alloc_start != 0)
 683                 seq_printf(seq, ",alloc_start=%llu",
 684                            (unsigned long long)info->alloc_start);
 685         if (info->thread_pool_size !=  min_t(unsigned long,
 686                                              num_online_cpus() + 2, 8))
 687                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 688         if (btrfs_test_opt(root, COMPRESS)) {
 689                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
 690                         compress_type = "zlib";
 691                 else
 692                         compress_type = "lzo";
 693                 if (btrfs_test_opt(root, FORCE_COMPRESS))
 694                         seq_printf(seq, ",compress-force=%s", compress_type);
 695                 else
 696                         seq_printf(seq, ",compress=%s", compress_type);
 697         }
 698         if (btrfs_test_opt(root, NOSSD))
 699                 seq_puts(seq, ",nossd");
 700         if (btrfs_test_opt(root, SSD_SPREAD))
 701                 seq_puts(seq, ",ssd_spread");
 702         else if (btrfs_test_opt(root, SSD))
 703                 seq_puts(seq, ",ssd");
 704         if (btrfs_test_opt(root, NOTREELOG))
 705                 seq_puts(seq, ",notreelog");
 706         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 707                 seq_puts(seq, ",flushoncommit");
 708         if (btrfs_test_opt(root, DISCARD))
 709                 seq_puts(seq, ",discard");
 710         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 711                 seq_puts(seq, ",noacl");
 712         if (btrfs_test_opt(root, SPACE_CACHE))
 713                 seq_puts(seq, ",space_cache");
 714         else
 715                 seq_puts(seq, ",nospace_cache");
 716         if (btrfs_test_opt(root, CLEAR_CACHE))
 717                 seq_puts(seq, ",clear_cache");
 718         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
 719                 seq_puts(seq, ",user_subvol_rm_allowed");
 720         if (btrfs_test_opt(root, ENOSPC_DEBUG))
 721                 seq_puts(seq, ",enospc_debug");
 722         if (btrfs_test_opt(root, AUTO_DEFRAG))
 723                 seq_puts(seq, ",autodefrag");
 724         if (btrfs_test_opt(root, INODE_MAP_CACHE))
 725                 seq_puts(seq, ",inode_cache");
 726         return 0;
 727 }
 728
 729 static int btrfs_test_super(struct super_block *s, void *data)
 730 {
 731         struct btrfs_root *test_root = data;
 732         struct btrfs_root *root = btrfs_sb(s);
 733
 734         /*
 735          * If this super block is going away, return false as it
 736          * can't match as an existing super block.
 737          */
 738         if (!atomic_read(&s->s_active))
 739                 return 0;
 740         return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
 741 }
 742
 743 static int btrfs_set_super(struct super_block *s, void *data)
 744 {
 745         s->s_fs_info = data;
 746
 747         return set_anon_super(s, data);
 748 }
 749
 750 /*
 751  * subvolumes are identified by ino 256
 752  */
 753 static inline int is_subvolume_inode(struct inode *inode)
 754 {
 755         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
 756                 return 1;
 757         return 0;
 758 }
 759
 760 /*
 761  * This will strip out the subvol=%s argument for an argument string and add
 762  * subvolid=0 to make sure we get the actual tree root for path walking to the
 763  * subvol we want.
 764  */
 765 static char *setup_root_args(char *args)
 766 {
 767         unsigned copied = 0;
 768         unsigned len = strlen(args) + 2;
 769         char *pos;
 770         char *ret;
 771
 772         /*
 773          * We need the same args as before, but minus
 774          *
 775          * subvol=a
 776          *
 777          * and add
 778          *
 779          * subvolid=0
 780          *
 781          * which is a difference of 2 characters, so we allocate strlen(args) +
 782          * 2 characters.
 783          */
 784         ret = kzalloc(len * sizeof(char), GFP_NOFS);
 785         if (!ret)
 786                 return NULL;
 787         pos = strstr(args, "subvol=");
 788
 789         /* This shouldn't happen, but just in case.. */
 790         if (!pos) {
 791                 kfree(ret);
 792                 return NULL;
 793         }
 794
 795         /*
 796          * The subvol=<> arg is not at the front of the string, copy everybody
 797          * up to that into ret.
 798          */
 799         if (pos != args) {
 800                 *pos = '\0';
 801                 strcpy(ret, args);
 802                 copied += strlen(args);
 803                 pos++;
 804         }
 805
 806         strncpy(ret + copied, "subvolid=0", len - copied);
 807
 808         /* Length of subvolid=0 */
 809         copied += 10;
 810
 811         /*
 812          * If there is no , after the subvol= option then we know there's no
 813          * other options and we can just return.
 814          */
 815         pos = strchr(pos, ',');
 816         if (!pos)
 817                 return ret;
 818
 819         /* Copy the rest of the arguments into our buffer */
 820         strncpy(ret + copied, pos, len - copied);
 821         copied += strlen(pos);
 822
 823         return ret;
 824 }
 825
 826 static struct dentry *mount_subvol(const char *subvol_name, int flags,
 827                                    const char *device_name, char *data)
 828 {
 829         struct super_block *s;
 830         struct dentry *root;
 831         struct vfsmount *mnt;
 832         struct mnt_namespace *ns_private;
 833         char *newargs;
 834         struct path path;
 835         int error;
 836
 837         newargs = setup_root_args(data);
 838         if (!newargs)
 839                 return ERR_PTR(-ENOMEM);
 840         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
 841                              newargs);
 842         kfree(newargs);
 843         if (IS_ERR(mnt))
 844                 return ERR_CAST(mnt);
 845
 846         ns_private = create_mnt_ns(mnt);
 847         if (IS_ERR(ns_private)) {
 848                 mntput(mnt);
 849                 return ERR_CAST(ns_private);
 850         }
 851
 852         /*
 853          * This will trigger the automount of the subvol so we can just
 854          * drop the mnt we have here and return the dentry that we
 855          * found.
 856          */
 857         error = vfs_path_lookup(mnt->mnt_root, mnt, subvol_name,
 858                                 LOOKUP_FOLLOW, &path);
 859         put_mnt_ns(ns_private);
 860         if (error)
 861                 return ERR_PTR(error);
 862
 863         if (!is_subvolume_inode(path.dentry->d_inode)) {
 864                 path_put(&path);
 865                 mntput(mnt);
 866                 error = -EINVAL;
 867                 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
 868                                 subvol_name);
 869                 return ERR_PTR(-EINVAL);
 870         }
 871
 872         /* Get a ref to the sb and the dentry we found and return it */
 873         s = path.mnt->mnt_sb;
 874         atomic_inc(&s->s_active);
 875         root = dget(path.dentry);
 876         path_put(&path);
 877         down_write(&s->s_umount);
 878
 879         return root;
 880 }
 881
 882 /*
 883  * Find a superblock for the given device / mount point.
 884  *
 885  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 886  *        for multiple device setup.  Make sure to keep it in sync.
 887  */
 888 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 889                 const char *device_name, void *data)
 890 {
 891         struct block_device *bdev = NULL;
 892         struct super_block *s;
 893         struct dentry *root;
 894         struct btrfs_fs_devices *fs_devices = NULL;
 895         struct btrfs_fs_info *fs_info = NULL;
 896         fmode_t mode = FMODE_READ;
 897         char *subvol_name = NULL;
 898         u64 subvol_objectid = 0;
 899         u64 subvol_rootid = 0;
 900         int error = 0;
 901
 902         if (!(flags & MS_RDONLY))
 903                 mode |= FMODE_WRITE;
 904
 905         error = btrfs_parse_early_options(data, mode, fs_type,
 906                                           &subvol_name, &subvol_objectid,
 907                                           &subvol_rootid, &fs_devices);
 908         if (error) {
 909                 kfree(subvol_name);
 910                 return ERR_PTR(error);
 911         }
 912
 913         if (subvol_name) {
 914                 root = mount_subvol(subvol_name, flags, device_name, data);
 915                 kfree(subvol_name);
 916                 return root;
 917         }
 918
 919         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
 920         if (error)
 921                 return ERR_PTR(error);
 922
 923         /*
 924          * Setup a dummy root and fs_info for test/set super.  This is because
 925          * we don't actually fill this stuff out until open_ctree, but we need
 926          * it for searching for existing supers, so this lets us do that and
 927          * then open_ctree will properly initialize everything later.
 928          */
 929         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
 930         if (!fs_info)
 931                 return ERR_PTR(-ENOMEM);
 932
 933         fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
 934         if (!fs_info->tree_root) {
 935                 error = -ENOMEM;
 936                 goto error_fs_info;
 937         }
 938         fs_info->tree_root->fs_info = fs_info;
 939         fs_info->fs_devices = fs_devices;
 940
 941         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
 942         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
 943         if (!fs_info->super_copy || !fs_info->super_for_commit) {
 944                 error = -ENOMEM;
 945                 goto error_fs_info;
 946         }
 947
 948         error = btrfs_open_devices(fs_devices, mode, fs_type);
 949         if (error)
 950                 goto error_fs_info;
 951
 952         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 953                 error = -EACCES;
 954                 goto error_close_devices;
 955         }
 956
 957         bdev = fs_devices->latest_bdev;
 958         s = sget(fs_type, btrfs_test_super, btrfs_set_super,
 959                  fs_info->tree_root);
 960         if (IS_ERR(s)) {
 961                 error = PTR_ERR(s);
 962                 goto error_close_devices;
 963         }
 964
 965         if (s->s_root) {
 966                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 967                         deactivate_locked_super(s);
 968                         error = -EBUSY;
 969                         goto error_close_devices;
 970                 }
 971
 972                 btrfs_close_devices(fs_devices);
 973                 free_fs_info(fs_info);
 974         } else {
 975                 char b[BDEVNAME_SIZE];
 976
 977                 s->s_flags = flags | MS_NOSEC;
 978                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 979                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 980                 error = btrfs_fill_super(s, fs_devices, data,
 981                                          flags & MS_SILENT ? 1 : 0);
 982                 if (error) {
 983                         deactivate_locked_super(s);
 984                         return ERR_PTR(error);
 985                 }
 986
 987                 s->s_flags |= MS_ACTIVE;
 988         }
 989
 990         root = get_default_root(s, subvol_objectid);
 991         if (IS_ERR(root)) {
 992                 deactivate_locked_super(s);
 993                 return root;
 994         }
 995
 996         return root;
 997
 998 error_close_devices:
 999         btrfs_close_devices(fs_devices);
1000 error_fs_info:
1001         free_fs_info(fs_info);
1002         return ERR_PTR(error);
1003 }
1004
1005 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1006 {
1007         struct btrfs_root *root = btrfs_sb(sb);
1008         int ret;
1009
1010         ret = btrfs_parse_options(root, data);
1011         if (ret)
1012                 return -EINVAL;
1013
1014         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1015                 return 0;
1016
1017         if (*flags & MS_RDONLY) {
1018                 sb->s_flags |= MS_RDONLY;
1019
1020                 ret =  btrfs_commit_super(root);
1021                 WARN_ON(ret);
1022         } else {
1023                 if (root->fs_info->fs_devices->rw_devices == 0)
1024                         return -EACCES;
1025
1026                 if (btrfs_super_log_root(root->fs_info->super_copy) != 0)
1027                         return -EINVAL;
1028
1029                 ret = btrfs_cleanup_fs_roots(root->fs_info);
1030                 WARN_ON(ret);
1031
1032                 /* recover relocation */
1033                 ret = btrfs_recover_relocation(root);
1034                 WARN_ON(ret);
1035
1036                 sb->s_flags &= ~MS_RDONLY;
1037         }
1038
1039         return 0;
1040 }
1041
1042 /* Used to sort the devices by max_avail(descending sort) */
1043 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1044                                        const void *dev_info2)
1045 {
1046         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1047             ((struct btrfs_device_info *)dev_info2)->max_avail)
1048                 return -1;
1049         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1050                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1051                 return 1;
1052         else
1053         return 0;
1054 }
1055
1056 /*
1057  * sort the devices by max_avail, in which max free extent size of each device
1058  * is stored.(Descending Sort)
1059  */
1060 static inline void btrfs_descending_sort_devices(
1061                                         struct btrfs_device_info *devices,
1062                                         size_t nr_devices)
1063 {
1064         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1065              btrfs_cmp_device_free_bytes, NULL);
1066 }
1067
1068 /*
1069  * The helper to calc the free space on the devices that can be used to store
1070  * file data.
1071  */
1072 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1073 {
1074         struct btrfs_fs_info *fs_info = root->fs_info;
1075         struct btrfs_device_info *devices_info;
1076         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1077         struct btrfs_device *device;
1078         u64 skip_space;
1079         u64 type;
1080         u64 avail_space;
1081         u64 used_space;
1082         u64 min_stripe_size;
1083         int min_stripes = 1, num_stripes = 1;
1084         int i = 0, nr_devices;
1085         int ret;
1086
1087         nr_devices = fs_info->fs_devices->open_devices;
1088         BUG_ON(!nr_devices);
1089
1090         devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1091                                GFP_NOFS);
1092         if (!devices_info)
1093                 return -ENOMEM;
1094
1095         /* calc min stripe number for data space alloction */
1096         type = btrfs_get_alloc_profile(root, 1);
1097         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1098                 min_stripes = 2;
1099                 num_stripes = nr_devices;
1100         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1101                 min_stripes = 2;
1102                 num_stripes = 2;
1103         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1104                 min_stripes = 4;
1105                 num_stripes = 4;
1106         }
1107
1108         if (type & BTRFS_BLOCK_GROUP_DUP)
1109                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1110         else
1111                 min_stripe_size = BTRFS_STRIPE_LEN;
1112
1113         list_for_each_entry(device, &fs_devices->devices, dev_list) {
1114                 if (!device->in_fs_metadata || !device->bdev)
1115                         continue;
1116
1117                 avail_space = device->total_bytes - device->bytes_used;
1118
1119                 /* align with stripe_len */
1120                 do_div(avail_space, BTRFS_STRIPE_LEN);
1121                 avail_space *= BTRFS_STRIPE_LEN;
1122
1123                 /*
1124                  * In order to avoid overwritting the superblock on the drive,
1125                  * btrfs starts at an offset of at least 1MB when doing chunk
1126                  * allocation.
1127                  */
1128                 skip_space = 1024 * 1024;
1129
1130                 /* user can set the offset in fs_info->alloc_start. */
1131                 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1132                     device->total_bytes)
1133                         skip_space = max(fs_info->alloc_start, skip_space);
1134
1135                 /*
1136                  * btrfs can not use the free space in [0, skip_space - 1],
1137                  * we must subtract it from the total. In order to implement
1138                  * it, we account the used space in this range first.
1139                  */
1140                 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1141                                                      &used_space);
1142                 if (ret) {
1143                         kfree(devices_info);
1144                         return ret;
1145                 }
1146
1147                 /* calc the free space in [0, skip_space - 1] */
1148                 skip_space -= used_space;
1149
1150                 /*
1151                  * we can use the free space in [0, skip_space - 1], subtract
1152                  * it from the total.
1153                  */
1154                 if (avail_space && avail_space >= skip_space)
1155                         avail_space -= skip_space;
1156                 else
1157                         avail_space = 0;
1158
1159                 if (avail_space < min_stripe_size)
1160                         continue;
1161
1162                 devices_info[i].dev = device;
1163                 devices_info[i].max_avail = avail_space;
1164
1165                 i++;
1166         }
1167
1168         nr_devices = i;
1169
1170         btrfs_descending_sort_devices(devices_info, nr_devices);
1171
1172         i = nr_devices - 1;
1173         avail_space = 0;
1174         while (nr_devices >= min_stripes) {
1175                 if (num_stripes > nr_devices)
1176                         num_stripes = nr_devices;
1177
1178                 if (devices_info[i].max_avail >= min_stripe_size) {
1179                         int j;
1180                         u64 alloc_size;
1181
1182                         avail_space += devices_info[i].max_avail * num_stripes;
1183                         alloc_size = devices_info[i].max_avail;
1184                         for (j = i + 1 - num_stripes; j <= i; j++)
1185                                 devices_info[j].max_avail -= alloc_size;
1186                 }
1187                 i--;
1188                 nr_devices--;
1189         }
1190
1191         kfree(devices_info);
1192         *free_bytes = avail_space;
1193         return 0;
1194 }
1195
1196 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1197 {
1198         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
1199         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1200         struct list_head *head = &root->fs_info->space_info;
1201         struct btrfs_space_info *found;
1202         u64 total_used = 0;
1203         u64 total_free_data = 0;
1204         int bits = dentry->d_sb->s_blocksize_bits;
1205         __be32 *fsid = (__be32 *)root->fs_info->fsid;
1206         int ret;
1207
1208         /* holding chunk_muext to avoid allocating new chunks */
1209         mutex_lock(&root->fs_info->chunk_mutex);
1210         rcu_read_lock();
1211         list_for_each_entry_rcu(found, head, list) {
1212                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1213                         total_free_data += found->disk_total - found->disk_used;
1214                         total_free_data -=
1215                                 btrfs_account_ro_block_groups_free_space(found);
1216                 }
1217
1218                 total_used += found->disk_used;
1219         }
1220         rcu_read_unlock();
1221
1222         buf->f_namelen = BTRFS_NAME_LEN;
1223         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1224         buf->f_bfree = buf->f_blocks - (total_used >> bits);
1225         buf->f_bsize = dentry->d_sb->s_blocksize;
1226         buf->f_type = BTRFS_SUPER_MAGIC;
1227         buf->f_bavail = total_free_data;
1228         ret = btrfs_calc_avail_data_space(root, &total_free_data);
1229         if (ret) {
1230                 mutex_unlock(&root->fs_info->chunk_mutex);
1231                 return ret;
1232         }
1233         buf->f_bavail += total_free_data;
1234         buf->f_bavail = buf->f_bavail >> bits;
1235         mutex_unlock(&root->fs_info->chunk_mutex);
1236
1237         /* We treat it as constant endianness (it doesn't matter _which_)
1238            because we want the fsid to come out the same whether mounted
1239            on a big-endian or little-endian host */
1240         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1241         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1242         /* Mask in the root object ID too, to disambiguate subvols */
1243         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1244         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1245
1246         return 0;
1247 }
1248
1249 static struct file_system_type btrfs_fs_type = {
1250         .owner          = THIS_MODULE,
1251         .name           = "btrfs",
1252         .mount          = btrfs_mount,
1253         .kill_sb        = kill_anon_super,
1254         .fs_flags       = FS_REQUIRES_DEV,
1255 };
1256
1257 /*
1258  * used by btrfsctl to scan devices when no FS is mounted
1259  */
1260 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1261                                 unsigned long arg)
1262 {
1263         struct btrfs_ioctl_vol_args *vol;
1264         struct btrfs_fs_devices *fs_devices;
1265         int ret = -ENOTTY;
1266
1267         if (!capable(CAP_SYS_ADMIN))
1268                 return -EPERM;
1269
1270         vol = memdup_user((void __user *)arg, sizeof(*vol));
1271         if (IS_ERR(vol))
1272                 return PTR_ERR(vol);
1273
1274         switch (cmd) {
1275         case BTRFS_IOC_SCAN_DEV:
1276                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1277                                             &btrfs_fs_type, &fs_devices);
1278                 break;
1279         }
1280
1281         kfree(vol);
1282         return ret;
1283 }
1284
1285 static int btrfs_freeze(struct super_block *sb)
1286 {
1287         struct btrfs_root *root = btrfs_sb(sb);
1288         mutex_lock(&root->fs_info->transaction_kthread_mutex);
1289         mutex_lock(&root->fs_info->cleaner_mutex);
1290         return 0;
1291 }
1292
1293 static int btrfs_unfreeze(struct super_block *sb)
1294 {
1295         struct btrfs_root *root = btrfs_sb(sb);
1296         mutex_unlock(&root->fs_info->cleaner_mutex);
1297         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1298         return 0;
1299 }
1300
1301 static void btrfs_fs_dirty_inode(struct inode *inode, int flags)
1302 {
1303         int ret;
1304
1305         ret = btrfs_dirty_inode(inode);
1306         if (ret)
1307                 printk_ratelimited(KERN_ERR "btrfs: fail to dirty inode %Lu "
1308                                    "error %d\n", btrfs_ino(inode), ret);
1309 }
1310
1311 static const struct super_operations btrfs_super_ops = {
1312         .drop_inode     = btrfs_drop_inode,
1313         .evict_inode    = btrfs_evict_inode,
1314         .put_super      = btrfs_put_super,
1315         .sync_fs        = btrfs_sync_fs,
1316         .show_options   = btrfs_show_options,
1317         .write_inode    = btrfs_write_inode,
1318         .dirty_inode    = btrfs_fs_dirty_inode,
1319         .alloc_inode    = btrfs_alloc_inode,
1320         .destroy_inode  = btrfs_destroy_inode,
1321         .statfs         = btrfs_statfs,
1322         .remount_fs     = btrfs_remount,
1323         .freeze_fs      = btrfs_freeze,
1324         .unfreeze_fs    = btrfs_unfreeze,
1325 };
1326
1327 static const struct file_operations btrfs_ctl_fops = {
1328         .unlocked_ioctl  = btrfs_control_ioctl,
1329         .compat_ioctl = btrfs_control_ioctl,
1330         .owner   = THIS_MODULE,
1331         .llseek = noop_llseek,
1332 };
1333
1334 static struct miscdevice btrfs_misc = {
1335         .minor          = BTRFS_MINOR,
1336         .name           = "btrfs-control",
1337         .fops           = &btrfs_ctl_fops
1338 };
1339
1340 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1341 MODULE_ALIAS("devname:btrfs-control");
1342
1343 static int btrfs_interface_init(void)
1344 {
1345         return misc_register(&btrfs_misc);
1346 }
1347
1348 static void btrfs_interface_exit(void)
1349 {
1350         if (misc_deregister(&btrfs_misc) < 0)
1351                 printk(KERN_INFO "misc_deregister failed for control device");
1352 }
1353
1354 static int __init init_btrfs_fs(void)
1355 {
1356         int err;
1357
1358         err = btrfs_init_sysfs();
1359         if (err)
1360                 return err;
1361
1362         err = btrfs_init_compress();
1363         if (err)
1364                 goto free_sysfs;
1365
1366         err = btrfs_init_cachep();
1367         if (err)
1368                 goto free_compress;
1369
1370         err = extent_io_init();
1371         if (err)
1372                 goto free_cachep;
1373
1374         err = extent_map_init();
1375         if (err)
1376                 goto free_extent_io;
1377
1378         err = btrfs_delayed_inode_init();
1379         if (err)
1380                 goto free_extent_map;
1381
1382         err = btrfs_interface_init();
1383         if (err)
1384                 goto free_delayed_inode;
1385
1386         err = register_filesystem(&btrfs_fs_type);
1387         if (err)
1388                 goto unregister_ioctl;
1389
1390         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1391         return 0;
1392
1393 unregister_ioctl:
1394         btrfs_interface_exit();
1395 free_delayed_inode:
1396         btrfs_delayed_inode_exit();
1397 free_extent_map:
1398         extent_map_exit();
1399 free_extent_io:
1400         extent_io_exit();
1401 free_cachep:
1402         btrfs_destroy_cachep();
1403 free_compress:
1404         btrfs_exit_compress();
1405 free_sysfs:
1406         btrfs_exit_sysfs();
1407         return err;
1408 }
1409
1410 static void __exit exit_btrfs_fs(void)
1411 {
1412         btrfs_destroy_cachep();
1413         btrfs_delayed_inode_exit();
1414         extent_map_exit();
1415         extent_io_exit();
1416         btrfs_interface_exit();
1417         unregister_filesystem(&btrfs_fs_type);
1418         btrfs_exit_sysfs();
1419         btrfs_cleanup_fs_uuids();
1420         btrfs_exit_compress();
1421 }
1422
1423 module_init(init_btrfs_fs)
1424 module_exit(exit_btrfs_fs)
1425
1426 MODULE_LICENSE("GPL");