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 "compat.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 "ioctl.h"
  51 #include "print-tree.h"
  52 #include "xattr.h"
  53 #include "volumes.h"
  54 #include "version.h"
  55 #include "export.h"
  56 #include "compression.h"
  57
  58 #define CREATE_TRACE_POINTS
  59 #include <trace/events/btrfs.h>
  60
  61 static const struct super_operations btrfs_super_ops;
  62 static struct file_system_type btrfs_fs_type;
  63
  64 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
  65                                       char nbuf[16])
  66 {
  67         char *errstr = NULL;
  68
  69         switch (errno) {
  70         case -EIO:
  71                 errstr = "IO failure";
  72                 break;
  73         case -ENOMEM:
  74                 errstr = "Out of memory";
  75                 break;
  76         case -EROFS:
  77                 errstr = "Readonly filesystem";
  78                 break;
  79         default:
  80                 if (nbuf) {
  81                         if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
  82                                 errstr = nbuf;
  83                 }
  84                 break;
  85         }
  86
  87         return errstr;
  88 }
  89
  90 static void __save_error_info(struct btrfs_fs_info *fs_info)
  91 {
  92         /*
  93          * today we only save the error info into ram.  Long term we'll
  94          * also send it down to the disk
  95          */
  96         fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
  97 }
  98
  99 /* NOTE:
 100  *      We move write_super stuff at umount in order to avoid deadlock
 101  *      for umount hold all lock.
 102  */
 103 static void save_error_info(struct btrfs_fs_info *fs_info)
 104 {
 105         __save_error_info(fs_info);
 106 }
 107
 108 /* btrfs handle error by forcing the filesystem readonly */
 109 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 110 {
 111         struct super_block *sb = fs_info->sb;
 112
 113         if (sb->s_flags & MS_RDONLY)
 114                 return;
 115
 116         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
 117                 sb->s_flags |= MS_RDONLY;
 118                 printk(KERN_INFO "btrfs is forced readonly\n");
 119         }
 120 }
 121
 122 /*
 123  * __btrfs_std_error decodes expected errors from the caller and
 124  * invokes the approciate error response.
 125  */
 126 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 127                      unsigned int line, int errno)
 128 {
 129         struct super_block *sb = fs_info->sb;
 130         char nbuf[16];
 131         const char *errstr;
 132
 133         /*
 134          * Special case: if the error is EROFS, and we're already
 135          * under MS_RDONLY, then it is safe here.
 136          */
 137         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 138                 return;
 139
 140         errstr = btrfs_decode_error(fs_info, errno, nbuf);
 141         printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
 142                 sb->s_id, function, line, errstr);
 143         save_error_info(fs_info);
 144
 145         btrfs_handle_error(fs_info);
 146 }
 147
 148 static void btrfs_put_super(struct super_block *sb)
 149 {
 150         struct btrfs_root *root = btrfs_sb(sb);
 151         int ret;
 152
 153         ret = close_ctree(root);
 154         sb->s_fs_info = NULL;
 155
 156         (void)ret; /* FIXME: need to fix VFS to return error? */
 157 }
 158
 159 enum {
 160         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 161         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 162         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 163         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 164         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 165         Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
 166         Opt_enospc_debug, Opt_subvolrootid, Opt_defrag,
 167         Opt_inode_cache, Opt_no_space_cache, Opt_recovery, Opt_err,
 168 };
 169
 170 static match_table_t tokens = {
 171         {Opt_degraded, "degraded"},
 172         {Opt_subvol, "subvol=%s"},
 173         {Opt_subvolid, "subvolid=%d"},
 174         {Opt_device, "device=%s"},
 175         {Opt_nodatasum, "nodatasum"},
 176         {Opt_nodatacow, "nodatacow"},
 177         {Opt_nobarrier, "nobarrier"},
 178         {Opt_max_inline, "max_inline=%s"},
 179         {Opt_alloc_start, "alloc_start=%s"},
 180         {Opt_thread_pool, "thread_pool=%d"},
 181         {Opt_compress, "compress"},
 182         {Opt_compress_type, "compress=%s"},
 183         {Opt_compress_force, "compress-force"},
 184         {Opt_compress_force_type, "compress-force=%s"},
 185         {Opt_ssd, "ssd"},
 186         {Opt_ssd_spread, "ssd_spread"},
 187         {Opt_nossd, "nossd"},
 188         {Opt_noacl, "noacl"},
 189         {Opt_notreelog, "notreelog"},
 190         {Opt_flushoncommit, "flushoncommit"},
 191         {Opt_ratio, "metadata_ratio=%d"},
 192         {Opt_discard, "discard"},
 193         {Opt_space_cache, "space_cache"},
 194         {Opt_clear_cache, "clear_cache"},
 195         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 196         {Opt_enospc_debug, "enospc_debug"},
 197         {Opt_subvolrootid, "subvolrootid=%d"},
 198         {Opt_defrag, "autodefrag"},
 199         {Opt_inode_cache, "inode_cache"},
 200         {Opt_no_space_cache, "no_space_cache"},
 201         {Opt_recovery, "recovery"},
 202         {Opt_err, NULL},
 203 };
 204
 205 /*
 206  * Regular mount options parser.  Everything that is needed only when
 207  * reading in a new superblock is parsed here.
 208  */
 209 int btrfs_parse_options(struct btrfs_root *root, char *options)
 210 {
 211         struct btrfs_fs_info *info = root->fs_info;
 212         substring_t args[MAX_OPT_ARGS];
 213         char *p, *num, *orig = NULL;
 214         u64 cache_gen;
 215         int intarg;
 216         int ret = 0;
 217         char *compress_type;
 218         bool compress_force = false;
 219
 220         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 221         if (cache_gen)
 222                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 223
 224         if (!options)
 225                 goto out;
 226
 227         /*
 228          * strsep changes the string, duplicate it because parse_options
 229          * gets called twice
 230          */
 231         options = kstrdup(options, GFP_NOFS);
 232         if (!options)
 233                 return -ENOMEM;
 234
 235         orig = options;
 236
 237         while ((p = strsep(&options, ",")) != NULL) {
 238                 int token;
 239                 if (!*p)
 240                         continue;
 241
 242                 token = match_token(p, tokens, args);
 243                 switch (token) {
 244                 case Opt_degraded:
 245                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 246                         btrfs_set_opt(info->mount_opt, DEGRADED);
 247                         break;
 248                 case Opt_subvol:
 249                 case Opt_subvolid:
 250                 case Opt_subvolrootid:
 251                 case Opt_device:
 252                         /*
 253                          * These are parsed by btrfs_parse_early_options
 254                          * and can be happily ignored here.
 255                          */
 256                         break;
 257                 case Opt_nodatasum:
 258                         printk(KERN_INFO "btrfs: setting nodatasum\n");
 259                         btrfs_set_opt(info->mount_opt, NODATASUM);
 260                         break;
 261                 case Opt_nodatacow:
 262                         printk(KERN_INFO "btrfs: setting nodatacow\n");
 263                         btrfs_set_opt(info->mount_opt, NODATACOW);
 264                         btrfs_set_opt(info->mount_opt, NODATASUM);
 265                         break;
 266                 case Opt_compress_force:
 267                 case Opt_compress_force_type:
 268                         compress_force = true;
 269                 case Opt_compress:
 270                 case Opt_compress_type:
 271                         if (token == Opt_compress ||
 272                             token == Opt_compress_force ||
 273                             strcmp(args[0].from, "zlib") == 0) {
 274                                 compress_type = "zlib";
 275                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 276                         } else if (strcmp(args[0].from, "lzo") == 0) {
 277                                 compress_type = "lzo";
 278                                 info->compress_type = BTRFS_COMPRESS_LZO;
 279                         } else {
 280                                 ret = -EINVAL;
 281                                 goto out;
 282                         }
 283
 284                         btrfs_set_opt(info->mount_opt, COMPRESS);
 285                         if (compress_force) {
 286                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 287                                 pr_info("btrfs: force %s compression\n",
 288                                         compress_type);
 289                         } else
 290                                 pr_info("btrfs: use %s compression\n",
 291                                         compress_type);
 292                         break;
 293                 case Opt_ssd:
 294                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 295                         btrfs_set_opt(info->mount_opt, SSD);
 296                         break;
 297                 case Opt_ssd_spread:
 298                         printk(KERN_INFO "btrfs: use spread ssd "
 299                                "allocation scheme\n");
 300                         btrfs_set_opt(info->mount_opt, SSD);
 301                         btrfs_set_opt(info->mount_opt, SSD_SPREAD);
 302                         break;
 303                 case Opt_nossd:
 304                         printk(KERN_INFO "btrfs: not using ssd allocation "
 305                                "scheme\n");
 306                         btrfs_set_opt(info->mount_opt, NOSSD);
 307                         btrfs_clear_opt(info->mount_opt, SSD);
 308                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
 309                         break;
 310                 case Opt_nobarrier:
 311                         printk(KERN_INFO "btrfs: turning off barriers\n");
 312                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 313                         break;
 314                 case Opt_thread_pool:
 315                         intarg = 0;
 316                         match_int(&args[0], &intarg);
 317                         if (intarg) {
 318                                 info->thread_pool_size = intarg;
 319                                 printk(KERN_INFO "btrfs: thread pool %d\n",
 320                                        info->thread_pool_size);
 321                         }
 322                         break;
 323                 case Opt_max_inline:
 324                         num = match_strdup(&args[0]);
 325                         if (num) {
 326                                 info->max_inline = memparse(num, NULL);
 327                                 kfree(num);
 328
 329                                 if (info->max_inline) {
 330                                         info->max_inline = max_t(u64,
 331                                                 info->max_inline,
 332                                                 root->sectorsize);
 333                                 }
 334                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 335                                         (unsigned long long)info->max_inline);
 336                         }
 337                         break;
 338                 case Opt_alloc_start:
 339                         num = match_strdup(&args[0]);
 340                         if (num) {
 341                                 info->alloc_start = memparse(num, NULL);
 342                                 kfree(num);
 343                                 printk(KERN_INFO
 344                                         "btrfs: allocations start at %llu\n",
 345                                         (unsigned long long)info->alloc_start);
 346                         }
 347                         break;
 348                 case Opt_noacl:
 349                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 350                         break;
 351                 case Opt_notreelog:
 352                         printk(KERN_INFO "btrfs: disabling tree log\n");
 353                         btrfs_set_opt(info->mount_opt, NOTREELOG);
 354                         break;
 355                 case Opt_flushoncommit:
 356                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
 357                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
 358                         break;
 359                 case Opt_ratio:
 360                         intarg = 0;
 361                         match_int(&args[0], &intarg);
 362                         if (intarg) {
 363                                 info->metadata_ratio = intarg;
 364                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
 365                                        info->metadata_ratio);
 366                         }
 367                         break;
 368                 case Opt_discard:
 369                         btrfs_set_opt(info->mount_opt, DISCARD);
 370                         break;
 371                 case Opt_space_cache:
 372                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 373                         break;
 374                 case Opt_no_space_cache:
 375                         printk(KERN_INFO "btrfs: disabling disk space caching\n");
 376                         btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
 377                         break;
 378                 case Opt_inode_cache:
 379                         printk(KERN_INFO "btrfs: enabling inode map caching\n");
 380                         btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
 381                         break;
 382                 case Opt_clear_cache:
 383                         printk(KERN_INFO "btrfs: force clearing of disk cache\n");
 384                         btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
 385                         break;
 386                 case Opt_user_subvol_rm_allowed:
 387                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 388                         break;
 389                 case Opt_enospc_debug:
 390                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 391                         break;
 392                 case Opt_defrag:
 393                         printk(KERN_INFO "btrfs: enabling auto defrag");
 394                         btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
 395                         break;
 396                 case Opt_recovery:
 397                         printk(KERN_INFO "btrfs: enabling auto recovery");
 398                         btrfs_set_opt(info->mount_opt, RECOVERY);
 399                         break;
 400                 case Opt_err:
 401                         printk(KERN_INFO "btrfs: unrecognized mount option "
 402                                "'%s'\n", p);
 403                         ret = -EINVAL;
 404                         goto out;
 405                 default:
 406                         break;
 407                 }
 408         }
 409 out:
 410         if (!ret && btrfs_test_opt(root, SPACE_CACHE))
 411                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
 412         kfree(orig);
 413         return ret;
 414 }
 415
 416 /*
 417  * Parse mount options that are required early in the mount process.
 418  *
 419  * All other options will be parsed on much later in the mount process and
 420  * only when we need to allocate a new super block.
 421  */
 422 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 423                 void *holder, char **subvol_name, u64 *subvol_objectid,
 424                 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
 425 {
 426         substring_t args[MAX_OPT_ARGS];
 427         char *device_name, *opts, *orig, *p;
 428         int error = 0;
 429         int intarg;
 430
 431         if (!options)
 432                 return 0;
 433
 434         /*
 435          * strsep changes the string, duplicate it because parse_options
 436          * gets called twice
 437          */
 438         opts = kstrdup(options, GFP_KERNEL);
 439         if (!opts)
 440                 return -ENOMEM;
 441         orig = opts;
 442
 443         while ((p = strsep(&opts, ",")) != NULL) {
 444                 int token;
 445                 if (!*p)
 446                         continue;
 447
 448                 token = match_token(p, tokens, args);
 449                 switch (token) {
 450                 case Opt_subvol:
 451                         *subvol_name = match_strdup(&args[0]);
 452                         break;
 453                 case Opt_subvolid:
 454                         intarg = 0;
 455                         error = match_int(&args[0], &intarg);
 456                         if (!error) {
 457                                 /* we want the original fs_tree */
 458                                 if (!intarg)
 459                                         *subvol_objectid =
 460                                                 BTRFS_FS_TREE_OBJECTID;
 461                                 else
 462                                         *subvol_objectid = intarg;
 463                         }
 464                         break;
 465                 case Opt_subvolrootid:
 466                         intarg = 0;
 467                         error = match_int(&args[0], &intarg);
 468                         if (!error) {
 469                                 /* we want the original fs_tree */
 470                                 if (!intarg)
 471                                         *subvol_rootid =
 472                                                 BTRFS_FS_TREE_OBJECTID;
 473                                 else
 474                                         *subvol_rootid = intarg;
 475                         }
 476                         break;
 477                 case Opt_device:
 478                         device_name = match_strdup(&args[0]);
 479                         if (!device_name) {
 480                                 error = -ENOMEM;
 481                                 goto out;
 482                         }
 483                         error = btrfs_scan_one_device(device_name,
 484                                         flags, holder, fs_devices);
 485                         kfree(device_name);
 486                         if (error)
 487                                 goto out;
 488                         break;
 489                 default:
 490                         break;
 491                 }
 492         }
 493
 494 out:
 495         kfree(orig);
 496         return error;
 497 }
 498
 499 static struct dentry *get_default_root(struct super_block *sb,
 500                                        u64 subvol_objectid)
 501 {
 502         struct btrfs_root *root = sb->s_fs_info;
 503         struct btrfs_root *new_root;
 504         struct btrfs_dir_item *di;
 505         struct btrfs_path *path;
 506         struct btrfs_key location;
 507         struct inode *inode;
 508         u64 dir_id;
 509         int new = 0;
 510
 511         /*
 512          * We have a specific subvol we want to mount, just setup location and
 513          * go look up the root.
 514          */
 515         if (subvol_objectid) {
 516                 location.objectid = subvol_objectid;
 517                 location.type = BTRFS_ROOT_ITEM_KEY;
 518                 location.offset = (u64)-1;
 519                 goto find_root;
 520         }
 521
 522         path = btrfs_alloc_path();
 523         if (!path)
 524                 return ERR_PTR(-ENOMEM);
 525         path->leave_spinning = 1;
 526
 527         /*
 528          * Find the "default" dir item which points to the root item that we
 529          * will mount by default if we haven't been given a specific subvolume
 530          * to mount.
 531          */
 532         dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
 533         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
 534         if (IS_ERR(di)) {
 535                 btrfs_free_path(path);
 536                 return ERR_CAST(di);
 537         }
 538         if (!di) {
 539                 /*
 540                  * Ok the default dir item isn't there.  This is weird since
 541                  * it's always been there, but don't freak out, just try and
 542                  * mount to root most subvolume.
 543                  */
 544                 btrfs_free_path(path);
 545                 dir_id = BTRFS_FIRST_FREE_OBJECTID;
 546                 new_root = root->fs_info->fs_root;
 547                 goto setup_root;
 548         }
 549
 550         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
 551         btrfs_free_path(path);
 552
 553 find_root:
 554         new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
 555         if (IS_ERR(new_root))
 556                 return ERR_CAST(new_root);
 557
 558         if (btrfs_root_refs(&new_root->root_item) == 0)
 559                 return ERR_PTR(-ENOENT);
 560
 561         dir_id = btrfs_root_dirid(&new_root->root_item);
 562 setup_root:
 563         location.objectid = dir_id;
 564         location.type = BTRFS_INODE_ITEM_KEY;
 565         location.offset = 0;
 566
 567         inode = btrfs_iget(sb, &location, new_root, &new);
 568         if (IS_ERR(inode))
 569                 return ERR_CAST(inode);
 570
 571         /*
 572          * If we're just mounting the root most subvol put the inode and return
 573          * a reference to the dentry.  We will have already gotten a reference
 574          * to the inode in btrfs_fill_super so we're good to go.
 575          */
 576         if (!new && sb->s_root->d_inode == inode) {
 577                 iput(inode);
 578                 return dget(sb->s_root);
 579         }
 580
 581         return d_obtain_alias(inode);
 582 }
 583
 584 static int btrfs_fill_super(struct super_block *sb,
 585                             struct btrfs_fs_devices *fs_devices,
 586                             void *data, int silent)
 587 {
 588         struct inode *inode;
 589         struct dentry *root_dentry;
 590         struct btrfs_root *tree_root;
 591         struct btrfs_key key;
 592         int err;
 593
 594         sb->s_maxbytes = MAX_LFS_FILESIZE;
 595         sb->s_magic = BTRFS_SUPER_MAGIC;
 596         sb->s_op = &btrfs_super_ops;
 597         sb->s_d_op = &btrfs_dentry_operations;
 598         sb->s_export_op = &btrfs_export_ops;
 599         sb->s_xattr = btrfs_xattr_handlers;
 600         sb->s_time_gran = 1;
 601 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 602         sb->s_flags |= MS_POSIXACL;
 603 #endif
 604
 605         tree_root = open_ctree(sb, fs_devices, (char *)data);
 606
 607         if (IS_ERR(tree_root)) {
 608                 printk("btrfs: open_ctree failed\n");
 609                 return PTR_ERR(tree_root);
 610         }
 611         sb->s_fs_info = tree_root;
 612
 613         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 614         key.type = BTRFS_INODE_ITEM_KEY;
 615         key.offset = 0;
 616         inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
 617         if (IS_ERR(inode)) {
 618                 err = PTR_ERR(inode);
 619                 goto fail_close;
 620         }
 621
 622         root_dentry = d_alloc_root(inode);
 623         if (!root_dentry) {
 624                 iput(inode);
 625                 err = -ENOMEM;
 626                 goto fail_close;
 627         }
 628
 629         sb->s_root = root_dentry;
 630
 631         save_mount_options(sb, data);
 632         cleancache_init_fs(sb);
 633         return 0;
 634
 635 fail_close:
 636         close_ctree(tree_root);
 637         return err;
 638 }
 639
 640 int btrfs_sync_fs(struct super_block *sb, int wait)
 641 {
 642         struct btrfs_trans_handle *trans;
 643         struct btrfs_root *root = btrfs_sb(sb);
 644         int ret;
 645
 646         trace_btrfs_sync_fs(wait);
 647
 648         if (!wait) {
 649                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 650                 return 0;
 651         }
 652
 653         btrfs_start_delalloc_inodes(root, 0);
 654         btrfs_wait_ordered_extents(root, 0, 0);
 655
 656         trans = btrfs_start_transaction(root, 0);
 657         if (IS_ERR(trans))
 658                 return PTR_ERR(trans);
 659         ret = btrfs_commit_transaction(trans, root);
 660         return ret;
 661 }
 662
 663 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 664 {
 665         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
 666         struct btrfs_fs_info *info = root->fs_info;
 667         char *compress_type;
 668
 669         if (btrfs_test_opt(root, DEGRADED))
 670                 seq_puts(seq, ",degraded");
 671         if (btrfs_test_opt(root, NODATASUM))
 672                 seq_puts(seq, ",nodatasum");
 673         if (btrfs_test_opt(root, NODATACOW))
 674                 seq_puts(seq, ",nodatacow");
 675         if (btrfs_test_opt(root, NOBARRIER))
 676                 seq_puts(seq, ",nobarrier");
 677         if (info->max_inline != 8192 * 1024)
 678                 seq_printf(seq, ",max_inline=%llu",
 679                            (unsigned long long)info->max_inline);
 680         if (info->alloc_start != 0)
 681                 seq_printf(seq, ",alloc_start=%llu",
 682                            (unsigned long long)info->alloc_start);
 683         if (info->thread_pool_size !=  min_t(unsigned long,
 684                                              num_online_cpus() + 2, 8))
 685                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 686         if (btrfs_test_opt(root, COMPRESS)) {
 687                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
 688                         compress_type = "zlib";
 689                 else
 690                         compress_type = "lzo";
 691                 if (btrfs_test_opt(root, FORCE_COMPRESS))
 692                         seq_printf(seq, ",compress-force=%s", compress_type);
 693                 else
 694                         seq_printf(seq, ",compress=%s", compress_type);
 695         }
 696         if (btrfs_test_opt(root, NOSSD))
 697                 seq_puts(seq, ",nossd");
 698         if (btrfs_test_opt(root, SSD_SPREAD))
 699                 seq_puts(seq, ",ssd_spread");
 700         else if (btrfs_test_opt(root, SSD))
 701                 seq_puts(seq, ",ssd");
 702         if (btrfs_test_opt(root, NOTREELOG))
 703                 seq_puts(seq, ",notreelog");
 704         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 705                 seq_puts(seq, ",flushoncommit");
 706         if (btrfs_test_opt(root, DISCARD))
 707                 seq_puts(seq, ",discard");
 708         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 709                 seq_puts(seq, ",noacl");
 710         if (btrfs_test_opt(root, SPACE_CACHE))
 711                 seq_puts(seq, ",space_cache");
 712         else
 713                 seq_puts(seq, ",no_space_cache");
 714         if (btrfs_test_opt(root, CLEAR_CACHE))
 715                 seq_puts(seq, ",clear_cache");
 716         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
 717                 seq_puts(seq, ",user_subvol_rm_allowed");
 718         if (btrfs_test_opt(root, ENOSPC_DEBUG))
 719                 seq_puts(seq, ",enospc_debug");
 720         if (btrfs_test_opt(root, AUTO_DEFRAG))
 721                 seq_puts(seq, ",autodefrag");
 722         if (btrfs_test_opt(root, INODE_MAP_CACHE))
 723                 seq_puts(seq, ",inode_cache");
 724         return 0;
 725 }
 726
 727 static int btrfs_test_super(struct super_block *s, void *data)
 728 {
 729         struct btrfs_root *test_root = data;
 730         struct btrfs_root *root = btrfs_sb(s);
 731
 732         /*
 733          * If this super block is going away, return false as it
 734          * can't match as an existing super block.
 735          */
 736         if (!atomic_read(&s->s_active))
 737                 return 0;
 738         return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
 739 }
 740
 741 static int btrfs_set_super(struct super_block *s, void *data)
 742 {
 743         s->s_fs_info = data;
 744
 745         return set_anon_super(s, data);
 746 }
 747
 748 /*
 749  * subvolumes are identified by ino 256
 750  */
 751 static inline int is_subvolume_inode(struct inode *inode)
 752 {
 753         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
 754                 return 1;
 755         return 0;
 756 }
 757
 758 /*
 759  * This will strip out the subvol=%s argument for an argument string and add
 760  * subvolid=0 to make sure we get the actual tree root for path walking to the
 761  * subvol we want.
 762  */
 763 static char *setup_root_args(char *args)
 764 {
 765         unsigned copied = 0;
 766         unsigned len = strlen(args) + 2;
 767         char *pos;
 768         char *ret;
 769
 770         /*
 771          * We need the same args as before, but minus
 772          *
 773          * subvol=a
 774          *
 775          * and add
 776          *
 777          * subvolid=0
 778          *
 779          * which is a difference of 2 characters, so we allocate strlen(args) +
 780          * 2 characters.
 781          */
 782         ret = kzalloc(len * sizeof(char), GFP_NOFS);
 783         if (!ret)
 784                 return NULL;
 785         pos = strstr(args, "subvol=");
 786
 787         /* This shouldn't happen, but just in case.. */
 788         if (!pos) {
 789                 kfree(ret);
 790                 return NULL;
 791         }
 792
 793         /*
 794          * The subvol=<> arg is not at the front of the string, copy everybody
 795          * up to that into ret.
 796          */
 797         if (pos != args) {
 798                 *pos = '\0';
 799                 strcpy(ret, args);
 800                 copied += strlen(args);
 801                 pos++;
 802         }
 803
 804         strncpy(ret + copied, "subvolid=0", len - copied);
 805
 806         /* Length of subvolid=0 */
 807         copied += 10;
 808
 809         /*
 810          * If there is no , after the subvol= option then we know there's no
 811          * other options and we can just return.
 812          */
 813         pos = strchr(pos, ',');
 814         if (!pos)
 815                 return ret;
 816
 817         /* Copy the rest of the arguments into our buffer */
 818         strncpy(ret + copied, pos, len - copied);
 819         copied += strlen(pos);
 820
 821         return ret;
 822 }
 823
 824 static struct dentry *mount_subvol(const char *subvol_name, int flags,
 825                                    const char *device_name, char *data)
 826 {
 827         struct super_block *s;
 828         struct dentry *root;
 829         struct vfsmount *mnt;
 830         struct mnt_namespace *ns_private;
 831         char *newargs;
 832         struct path path;
 833         int error;
 834
 835         newargs = setup_root_args(data);
 836         if (!newargs)
 837                 return ERR_PTR(-ENOMEM);
 838         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
 839                              newargs);
 840         kfree(newargs);
 841         if (IS_ERR(mnt))
 842                 return ERR_CAST(mnt);
 843
 844         ns_private = create_mnt_ns(mnt);
 845         if (IS_ERR(ns_private)) {
 846                 mntput(mnt);
 847                 return ERR_CAST(ns_private);
 848         }
 849
 850         /*
 851          * This will trigger the automount of the subvol so we can just
 852          * drop the mnt we have here and return the dentry that we
 853          * found.
 854          */
 855         error = vfs_path_lookup(mnt->mnt_root, mnt, subvol_name,
 856                                 LOOKUP_FOLLOW, &path);
 857         put_mnt_ns(ns_private);
 858         if (error)
 859                 return ERR_PTR(error);
 860
 861         if (!is_subvolume_inode(path.dentry->d_inode)) {
 862                 path_put(&path);
 863                 mntput(mnt);
 864                 error = -EINVAL;
 865                 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
 866                                 subvol_name);
 867                 return ERR_PTR(-EINVAL);
 868         }
 869
 870         /* Get a ref to the sb and the dentry we found and return it */
 871         s = path.mnt->mnt_sb;
 872         atomic_inc(&s->s_active);
 873         root = dget(path.dentry);
 874         path_put(&path);
 875         down_write(&s->s_umount);
 876
 877         return root;
 878 }
 879
 880 /*
 881  * Find a superblock for the given device / mount point.
 882  *
 883  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 884  *        for multiple device setup.  Make sure to keep it in sync.
 885  */
 886 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 887                 const char *device_name, void *data)
 888 {
 889         struct block_device *bdev = NULL;
 890         struct super_block *s;
 891         struct dentry *root;
 892         struct btrfs_fs_devices *fs_devices = NULL;
 893         struct btrfs_root *tree_root = NULL;
 894         struct btrfs_fs_info *fs_info = NULL;
 895         fmode_t mode = FMODE_READ;
 896         char *subvol_name = NULL;
 897         u64 subvol_objectid = 0;
 898         u64 subvol_rootid = 0;
 899         int error = 0;
 900
 901         if (!(flags & MS_RDONLY))
 902                 mode |= FMODE_WRITE;
 903
 904         error = btrfs_parse_early_options(data, mode, fs_type,
 905                                           &subvol_name, &subvol_objectid,
 906                                           &subvol_rootid, &fs_devices);
 907         if (error)
 908                 return ERR_PTR(error);
 909
 910         if (subvol_name) {
 911                 root = mount_subvol(subvol_name, flags, device_name, data);
 912                 kfree(subvol_name);
 913                 return root;
 914         }
 915
 916         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
 917         if (error)
 918                 return ERR_PTR(error);
 919
 920         error = btrfs_open_devices(fs_devices, mode, fs_type);
 921         if (error)
 922                 return ERR_PTR(error);
 923
 924         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 925                 error = -EACCES;
 926                 goto error_close_devices;
 927         }
 928
 929         /*
 930          * Setup a dummy root and fs_info for test/set super.  This is because
 931          * we don't actually fill this stuff out until open_ctree, but we need
 932          * it for searching for existing supers, so this lets us do that and
 933          * then open_ctree will properly initialize everything later.
 934          */
 935         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
 936         tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
 937         if (!fs_info || !tree_root) {
 938                 error = -ENOMEM;
 939                 goto error_close_devices;
 940         }
 941         fs_info->tree_root = tree_root;
 942         fs_info->fs_devices = fs_devices;
 943         tree_root->fs_info = fs_info;
 944
 945         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
 946         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
 947         if (!fs_info->super_copy || !fs_info->super_for_commit) {
 948                 error = -ENOMEM;
 949                 goto error_close_devices;
 950         }
 951
 952         bdev = fs_devices->latest_bdev;
 953         s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
 954         if (IS_ERR(s)) {
 955                 error = PTR_ERR(s);
 956                 goto error_close_devices;
 957         }
 958
 959         if (s->s_root) {
 960                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 961                         deactivate_locked_super(s);
 962                         return ERR_PTR(-EBUSY);
 963                 }
 964
 965                 btrfs_close_devices(fs_devices);
 966                 free_fs_info(fs_info);
 967                 kfree(tree_root);
 968         } else {
 969                 char b[BDEVNAME_SIZE];
 970
 971                 s->s_flags = flags | MS_NOSEC;
 972                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 973                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 974                 error = btrfs_fill_super(s, fs_devices, data,
 975                                          flags & MS_SILENT ? 1 : 0);
 976                 if (error) {
 977                         deactivate_locked_super(s);
 978                         return ERR_PTR(error);
 979                 }
 980
 981                 s->s_flags |= MS_ACTIVE;
 982         }
 983
 984         root = get_default_root(s, subvol_objectid);
 985         if (IS_ERR(root)) {
 986                 deactivate_locked_super(s);
 987                 return root;
 988         }
 989
 990         return root;
 991
 992 error_close_devices:
 993         btrfs_close_devices(fs_devices);
 994         free_fs_info(fs_info);
 995         kfree(tree_root);
 996         return ERR_PTR(error);
 997 }
 998
 999 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1000 {
1001         struct btrfs_root *root = btrfs_sb(sb);
1002         int ret;
1003
1004         ret = btrfs_parse_options(root, data);
1005         if (ret)
1006                 return -EINVAL;
1007
1008         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1009                 return 0;
1010
1011         if (*flags & MS_RDONLY) {
1012                 sb->s_flags |= MS_RDONLY;
1013
1014                 ret =  btrfs_commit_super(root);
1015                 WARN_ON(ret);
1016         } else {
1017                 if (root->fs_info->fs_devices->rw_devices == 0)
1018                         return -EACCES;
1019
1020                 if (btrfs_super_log_root(root->fs_info->super_copy) != 0)
1021                         return -EINVAL;
1022
1023                 ret = btrfs_cleanup_fs_roots(root->fs_info);
1024                 WARN_ON(ret);
1025
1026                 /* recover relocation */
1027                 ret = btrfs_recover_relocation(root);
1028                 WARN_ON(ret);
1029
1030                 sb->s_flags &= ~MS_RDONLY;
1031         }
1032
1033         return 0;
1034 }
1035
1036 /* Used to sort the devices by max_avail(descending sort) */
1037 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1038                                        const void *dev_info2)
1039 {
1040         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1041             ((struct btrfs_device_info *)dev_info2)->max_avail)
1042                 return -1;
1043         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1044                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1045                 return 1;
1046         else
1047         return 0;
1048 }
1049
1050 /*
1051  * sort the devices by max_avail, in which max free extent size of each device
1052  * is stored.(Descending Sort)
1053  */
1054 static inline void btrfs_descending_sort_devices(
1055                                         struct btrfs_device_info *devices,
1056                                         size_t nr_devices)
1057 {
1058         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1059              btrfs_cmp_device_free_bytes, NULL);
1060 }
1061
1062 /*
1063  * The helper to calc the free space on the devices that can be used to store
1064  * file data.
1065  */
1066 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1067 {
1068         struct btrfs_fs_info *fs_info = root->fs_info;
1069         struct btrfs_device_info *devices_info;
1070         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1071         struct btrfs_device *device;
1072         u64 skip_space;
1073         u64 type;
1074         u64 avail_space;
1075         u64 used_space;
1076         u64 min_stripe_size;
1077         int min_stripes = 1;
1078         int i = 0, nr_devices;
1079         int ret;
1080
1081         nr_devices = fs_info->fs_devices->rw_devices;
1082         BUG_ON(!nr_devices);
1083
1084         devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1085                                GFP_NOFS);
1086         if (!devices_info)
1087                 return -ENOMEM;
1088
1089         /* calc min stripe number for data space alloction */
1090         type = btrfs_get_alloc_profile(root, 1);
1091         if (type & BTRFS_BLOCK_GROUP_RAID0)
1092                 min_stripes = 2;
1093         else if (type & BTRFS_BLOCK_GROUP_RAID1)
1094                 min_stripes = 2;
1095         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1096                 min_stripes = 4;
1097
1098         if (type & BTRFS_BLOCK_GROUP_DUP)
1099                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1100         else
1101                 min_stripe_size = BTRFS_STRIPE_LEN;
1102
1103         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
1104                 if (!device->in_fs_metadata)
1105                         continue;
1106
1107                 avail_space = device->total_bytes - device->bytes_used;
1108
1109                 /* align with stripe_len */
1110                 do_div(avail_space, BTRFS_STRIPE_LEN);
1111                 avail_space *= BTRFS_STRIPE_LEN;
1112
1113                 /*
1114                  * In order to avoid overwritting the superblock on the drive,
1115                  * btrfs starts at an offset of at least 1MB when doing chunk
1116                  * allocation.
1117                  */
1118                 skip_space = 1024 * 1024;
1119
1120                 /* user can set the offset in fs_info->alloc_start. */
1121                 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1122                     device->total_bytes)
1123                         skip_space = max(fs_info->alloc_start, skip_space);
1124
1125                 /*
1126                  * btrfs can not use the free space in [0, skip_space - 1],
1127                  * we must subtract it from the total. In order to implement
1128                  * it, we account the used space in this range first.
1129                  */
1130                 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1131                                                      &used_space);
1132                 if (ret) {
1133                         kfree(devices_info);
1134                         return ret;
1135                 }
1136
1137                 /* calc the free space in [0, skip_space - 1] */
1138                 skip_space -= used_space;
1139
1140                 /*
1141                  * we can use the free space in [0, skip_space - 1], subtract
1142                  * it from the total.
1143                  */
1144                 if (avail_space && avail_space >= skip_space)
1145                         avail_space -= skip_space;
1146                 else
1147                         avail_space = 0;
1148
1149                 if (avail_space < min_stripe_size)
1150                         continue;
1151
1152                 devices_info[i].dev = device;
1153                 devices_info[i].max_avail = avail_space;
1154
1155                 i++;
1156         }
1157
1158         nr_devices = i;
1159
1160         btrfs_descending_sort_devices(devices_info, nr_devices);
1161
1162         i = nr_devices - 1;
1163         avail_space = 0;
1164         while (nr_devices >= min_stripes) {
1165                 if (devices_info[i].max_avail >= min_stripe_size) {
1166                         int j;
1167                         u64 alloc_size;
1168
1169                         avail_space += devices_info[i].max_avail * min_stripes;
1170                         alloc_size = devices_info[i].max_avail;
1171                         for (j = i + 1 - min_stripes; j <= i; j++)
1172                                 devices_info[j].max_avail -= alloc_size;
1173                 }
1174                 i--;
1175                 nr_devices--;
1176         }
1177
1178         kfree(devices_info);
1179         *free_bytes = avail_space;
1180         return 0;
1181 }
1182
1183 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1184 {
1185         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
1186         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1187         struct list_head *head = &root->fs_info->space_info;
1188         struct btrfs_space_info *found;
1189         u64 total_used = 0;
1190         u64 total_free_data = 0;
1191         int bits = dentry->d_sb->s_blocksize_bits;
1192         __be32 *fsid = (__be32 *)root->fs_info->fsid;
1193         int ret;
1194
1195         /* holding chunk_muext to avoid allocating new chunks */
1196         mutex_lock(&root->fs_info->chunk_mutex);
1197         rcu_read_lock();
1198         list_for_each_entry_rcu(found, head, list) {
1199                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1200                         total_free_data += found->disk_total - found->disk_used;
1201                         total_free_data -=
1202                                 btrfs_account_ro_block_groups_free_space(found);
1203                 }
1204
1205                 total_used += found->disk_used;
1206         }
1207         rcu_read_unlock();
1208
1209         buf->f_namelen = BTRFS_NAME_LEN;
1210         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1211         buf->f_bfree = buf->f_blocks - (total_used >> bits);
1212         buf->f_bsize = dentry->d_sb->s_blocksize;
1213         buf->f_type = BTRFS_SUPER_MAGIC;
1214         buf->f_bavail = total_free_data;
1215         ret = btrfs_calc_avail_data_space(root, &total_free_data);
1216         if (ret) {
1217                 mutex_unlock(&root->fs_info->chunk_mutex);
1218                 return ret;
1219         }
1220         buf->f_bavail += total_free_data;
1221         buf->f_bavail = buf->f_bavail >> bits;
1222         mutex_unlock(&root->fs_info->chunk_mutex);
1223
1224         /* We treat it as constant endianness (it doesn't matter _which_)
1225            because we want the fsid to come out the same whether mounted
1226            on a big-endian or little-endian host */
1227         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1228         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1229         /* Mask in the root object ID too, to disambiguate subvols */
1230         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1231         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1232
1233         return 0;
1234 }
1235
1236 static struct file_system_type btrfs_fs_type = {
1237         .owner          = THIS_MODULE,
1238         .name           = "btrfs",
1239         .mount          = btrfs_mount,
1240         .kill_sb        = kill_anon_super,
1241         .fs_flags       = FS_REQUIRES_DEV,
1242 };
1243
1244 /*
1245  * used by btrfsctl to scan devices when no FS is mounted
1246  */
1247 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1248                                 unsigned long arg)
1249 {
1250         struct btrfs_ioctl_vol_args *vol;
1251         struct btrfs_fs_devices *fs_devices;
1252         int ret = -ENOTTY;
1253
1254         if (!capable(CAP_SYS_ADMIN))
1255                 return -EPERM;
1256
1257         vol = memdup_user((void __user *)arg, sizeof(*vol));
1258         if (IS_ERR(vol))
1259                 return PTR_ERR(vol);
1260
1261         switch (cmd) {
1262         case BTRFS_IOC_SCAN_DEV:
1263                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1264                                             &btrfs_fs_type, &fs_devices);
1265                 break;
1266         }
1267
1268         kfree(vol);
1269         return ret;
1270 }
1271
1272 static int btrfs_freeze(struct super_block *sb)
1273 {
1274         struct btrfs_root *root = btrfs_sb(sb);
1275         mutex_lock(&root->fs_info->transaction_kthread_mutex);
1276         mutex_lock(&root->fs_info->cleaner_mutex);
1277         return 0;
1278 }
1279
1280 static int btrfs_unfreeze(struct super_block *sb)
1281 {
1282         struct btrfs_root *root = btrfs_sb(sb);
1283         mutex_unlock(&root->fs_info->cleaner_mutex);
1284         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1285         return 0;
1286 }
1287
1288 static const struct super_operations btrfs_super_ops = {
1289         .drop_inode     = btrfs_drop_inode,
1290         .evict_inode    = btrfs_evict_inode,
1291         .put_super      = btrfs_put_super,
1292         .sync_fs        = btrfs_sync_fs,
1293         .show_options   = btrfs_show_options,
1294         .write_inode    = btrfs_write_inode,
1295         .dirty_inode    = btrfs_dirty_inode,
1296         .alloc_inode    = btrfs_alloc_inode,
1297         .destroy_inode  = btrfs_destroy_inode,
1298         .statfs         = btrfs_statfs,
1299         .remount_fs     = btrfs_remount,
1300         .freeze_fs      = btrfs_freeze,
1301         .unfreeze_fs    = btrfs_unfreeze,
1302 };
1303
1304 static const struct file_operations btrfs_ctl_fops = {
1305         .unlocked_ioctl  = btrfs_control_ioctl,
1306         .compat_ioctl = btrfs_control_ioctl,
1307         .owner   = THIS_MODULE,
1308         .llseek = noop_llseek,
1309 };
1310
1311 static struct miscdevice btrfs_misc = {
1312         .minor          = BTRFS_MINOR,
1313         .name           = "btrfs-control",
1314         .fops           = &btrfs_ctl_fops
1315 };
1316
1317 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1318 MODULE_ALIAS("devname:btrfs-control");
1319
1320 static int btrfs_interface_init(void)
1321 {
1322         return misc_register(&btrfs_misc);
1323 }
1324
1325 static void btrfs_interface_exit(void)
1326 {
1327         if (misc_deregister(&btrfs_misc) < 0)
1328                 printk(KERN_INFO "misc_deregister failed for control device");
1329 }
1330
1331 static int __init init_btrfs_fs(void)
1332 {
1333         int err;
1334
1335         err = btrfs_init_sysfs();
1336         if (err)
1337                 return err;
1338
1339         err = btrfs_init_compress();
1340         if (err)
1341                 goto free_sysfs;
1342
1343         err = btrfs_init_cachep();
1344         if (err)
1345                 goto free_compress;
1346
1347         err = extent_io_init();
1348         if (err)
1349                 goto free_cachep;
1350
1351         err = extent_map_init();
1352         if (err)
1353                 goto free_extent_io;
1354
1355         err = btrfs_delayed_inode_init();
1356         if (err)
1357                 goto free_extent_map;
1358
1359         err = btrfs_interface_init();
1360         if (err)
1361                 goto free_delayed_inode;
1362
1363         err = register_filesystem(&btrfs_fs_type);
1364         if (err)
1365                 goto unregister_ioctl;
1366
1367         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1368         return 0;
1369
1370 unregister_ioctl:
1371         btrfs_interface_exit();
1372 free_delayed_inode:
1373         btrfs_delayed_inode_exit();
1374 free_extent_map:
1375         extent_map_exit();
1376 free_extent_io:
1377         extent_io_exit();
1378 free_cachep:
1379         btrfs_destroy_cachep();
1380 free_compress:
1381         btrfs_exit_compress();
1382 free_sysfs:
1383         btrfs_exit_sysfs();
1384         return err;
1385 }
1386
1387 static void __exit exit_btrfs_fs(void)
1388 {
1389         btrfs_destroy_cachep();
1390         btrfs_delayed_inode_exit();
1391         extent_map_exit();
1392         extent_io_exit();
1393         btrfs_interface_exit();
1394         unregister_filesystem(&btrfs_fs_type);
1395         btrfs_exit_sysfs();
1396         btrfs_cleanup_fs_uuids();
1397         btrfs_exit_compress();
1398 }
1399
1400 module_init(init_btrfs_fs)
1401 module_exit(exit_btrfs_fs)
1402
1403 MODULE_LICENSE("GPL");