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, "nospace_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                         kfree(*subvol_name);
 452                         *subvol_name = match_strdup(&args[0]);
 453                         break;
 454                 case Opt_subvolid:
 455                         intarg = 0;
 456                         error = match_int(&args[0], &intarg);
 457                         if (!error) {
 458                                 /* we want the original fs_tree */
 459                                 if (!intarg)
 460                                         *subvol_objectid =
 461                                                 BTRFS_FS_TREE_OBJECTID;
 462                                 else
 463                                         *subvol_objectid = intarg;
 464                         }
 465                         break;
 466                 case Opt_subvolrootid:
 467                         intarg = 0;
 468                         error = match_int(&args[0], &intarg);
 469                         if (!error) {
 470                                 /* we want the original fs_tree */
 471                                 if (!intarg)
 472                                         *subvol_rootid =
 473                                                 BTRFS_FS_TREE_OBJECTID;
 474                                 else
 475                                         *subvol_rootid = intarg;
 476                         }
 477                         break;
 478                 case Opt_device:
 479                         device_name = match_strdup(&args[0]);
 480                         if (!device_name) {
 481                                 error = -ENOMEM;
 482                                 goto out;
 483                         }
 484                         error = btrfs_scan_one_device(device_name,
 485                                         flags, holder, fs_devices);
 486                         kfree(device_name);
 487                         if (error)
 488                                 goto out;
 489                         break;
 490                 default:
 491                         break;
 492                 }
 493         }
 494
 495 out:
 496         kfree(orig);
 497         return error;
 498 }
 499
 500 static struct dentry *get_default_root(struct super_block *sb,
 501                                        u64 subvol_objectid)
 502 {
 503         struct btrfs_root *root = sb->s_fs_info;
 504         struct btrfs_root *new_root;
 505         struct btrfs_dir_item *di;
 506         struct btrfs_path *path;
 507         struct btrfs_key location;
 508         struct inode *inode;
 509         u64 dir_id;
 510         int new = 0;
 511
 512         /*
 513          * We have a specific subvol we want to mount, just setup location and
 514          * go look up the root.
 515          */
 516         if (subvol_objectid) {
 517                 location.objectid = subvol_objectid;
 518                 location.type = BTRFS_ROOT_ITEM_KEY;
 519                 location.offset = (u64)-1;
 520                 goto find_root;
 521         }
 522
 523         path = btrfs_alloc_path();
 524         if (!path)
 525                 return ERR_PTR(-ENOMEM);
 526         path->leave_spinning = 1;
 527
 528         /*
 529          * Find the "default" dir item which points to the root item that we
 530          * will mount by default if we haven't been given a specific subvolume
 531          * to mount.
 532          */
 533         dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
 534         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
 535         if (IS_ERR(di)) {
 536                 btrfs_free_path(path);
 537                 return ERR_CAST(di);
 538         }
 539         if (!di) {
 540                 /*
 541                  * Ok the default dir item isn't there.  This is weird since
 542                  * it's always been there, but don't freak out, just try and
 543                  * mount to root most subvolume.
 544                  */
 545                 btrfs_free_path(path);
 546                 dir_id = BTRFS_FIRST_FREE_OBJECTID;
 547                 new_root = root->fs_info->fs_root;
 548                 goto setup_root;
 549         }
 550
 551         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
 552         btrfs_free_path(path);
 553
 554 find_root:
 555         new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
 556         if (IS_ERR(new_root))
 557                 return ERR_CAST(new_root);
 558
 559         if (btrfs_root_refs(&new_root->root_item) == 0)
 560                 return ERR_PTR(-ENOENT);
 561
 562         dir_id = btrfs_root_dirid(&new_root->root_item);
 563 setup_root:
 564         location.objectid = dir_id;
 565         location.type = BTRFS_INODE_ITEM_KEY;
 566         location.offset = 0;
 567
 568         inode = btrfs_iget(sb, &location, new_root, &new);
 569         if (IS_ERR(inode))
 570                 return ERR_CAST(inode);
 571
 572         /*
 573          * If we're just mounting the root most subvol put the inode and return
 574          * a reference to the dentry.  We will have already gotten a reference
 575          * to the inode in btrfs_fill_super so we're good to go.
 576          */
 577         if (!new && sb->s_root->d_inode == inode) {
 578                 iput(inode);
 579                 return dget(sb->s_root);
 580         }
 581
 582         return d_obtain_alias(inode);
 583 }
 584
 585 static int btrfs_fill_super(struct super_block *sb,
 586                             struct btrfs_fs_devices *fs_devices,
 587                             void *data, int silent)
 588 {
 589         struct inode *inode;
 590         struct dentry *root_dentry;
 591         struct btrfs_root *tree_root;
 592         struct btrfs_key key;
 593         int err;
 594
 595         sb->s_maxbytes = MAX_LFS_FILESIZE;
 596         sb->s_magic = BTRFS_SUPER_MAGIC;
 597         sb->s_op = &btrfs_super_ops;
 598         sb->s_d_op = &btrfs_dentry_operations;
 599         sb->s_export_op = &btrfs_export_ops;
 600         sb->s_xattr = btrfs_xattr_handlers;
 601         sb->s_time_gran = 1;
 602 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 603         sb->s_flags |= MS_POSIXACL;
 604 #endif
 605
 606         tree_root = open_ctree(sb, fs_devices, (char *)data);
 607
 608         if (IS_ERR(tree_root)) {
 609                 printk("btrfs: open_ctree failed\n");
 610                 return PTR_ERR(tree_root);
 611         }
 612         sb->s_fs_info = tree_root;
 613
 614         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 615         key.type = BTRFS_INODE_ITEM_KEY;
 616         key.offset = 0;
 617         inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
 618         if (IS_ERR(inode)) {
 619                 err = PTR_ERR(inode);
 620                 goto fail_close;
 621         }
 622
 623         root_dentry = d_alloc_root(inode);
 624         if (!root_dentry) {
 625                 iput(inode);
 626                 err = -ENOMEM;
 627                 goto fail_close;
 628         }
 629
 630         sb->s_root = root_dentry;
 631
 632         save_mount_options(sb, data);
 633         cleancache_init_fs(sb);
 634         return 0;
 635
 636 fail_close:
 637         close_ctree(tree_root);
 638         return err;
 639 }
 640
 641 int btrfs_sync_fs(struct super_block *sb, int wait)
 642 {
 643         struct btrfs_trans_handle *trans;
 644         struct btrfs_root *root = btrfs_sb(sb);
 645         int ret;
 646
 647         trace_btrfs_sync_fs(wait);
 648
 649         if (!wait) {
 650                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 651                 return 0;
 652         }
 653
 654         btrfs_start_delalloc_inodes(root, 0);
 655         btrfs_wait_ordered_extents(root, 0, 0);
 656
 657         trans = btrfs_start_transaction(root, 0);
 658         if (IS_ERR(trans))
 659                 return PTR_ERR(trans);
 660         ret = btrfs_commit_transaction(trans, root);
 661         return ret;
 662 }
 663
 664 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 665 {
 666         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
 667         struct btrfs_fs_info *info = root->fs_info;
 668         char *compress_type;
 669
 670         if (btrfs_test_opt(root, DEGRADED))
 671                 seq_puts(seq, ",degraded");
 672         if (btrfs_test_opt(root, NODATASUM))
 673                 seq_puts(seq, ",nodatasum");
 674         if (btrfs_test_opt(root, NODATACOW))
 675                 seq_puts(seq, ",nodatacow");
 676         if (btrfs_test_opt(root, NOBARRIER))
 677                 seq_puts(seq, ",nobarrier");
 678         if (info->max_inline != 8192 * 1024)
 679                 seq_printf(seq, ",max_inline=%llu",
 680                            (unsigned long long)info->max_inline);
 681         if (info->alloc_start != 0)
 682                 seq_printf(seq, ",alloc_start=%llu",
 683                            (unsigned long long)info->alloc_start);
 684         if (info->thread_pool_size !=  min_t(unsigned long,
 685                                              num_online_cpus() + 2, 8))
 686                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 687         if (btrfs_test_opt(root, COMPRESS)) {
 688                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
 689                         compress_type = "zlib";
 690                 else
 691                         compress_type = "lzo";
 692                 if (btrfs_test_opt(root, FORCE_COMPRESS))
 693                         seq_printf(seq, ",compress-force=%s", compress_type);
 694                 else
 695                         seq_printf(seq, ",compress=%s", compress_type);
 696         }
 697         if (btrfs_test_opt(root, NOSSD))
 698                 seq_puts(seq, ",nossd");
 699         if (btrfs_test_opt(root, SSD_SPREAD))
 700                 seq_puts(seq, ",ssd_spread");
 701         else if (btrfs_test_opt(root, SSD))
 702                 seq_puts(seq, ",ssd");
 703         if (btrfs_test_opt(root, NOTREELOG))
 704                 seq_puts(seq, ",notreelog");
 705         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 706                 seq_puts(seq, ",flushoncommit");
 707         if (btrfs_test_opt(root, DISCARD))
 708                 seq_puts(seq, ",discard");
 709         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 710                 seq_puts(seq, ",noacl");
 711         if (btrfs_test_opt(root, SPACE_CACHE))
 712                 seq_puts(seq, ",space_cache");
 713         else
 714                 seq_puts(seq, ",nospace_cache");
 715         if (btrfs_test_opt(root, CLEAR_CACHE))
 716                 seq_puts(seq, ",clear_cache");
 717         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
 718                 seq_puts(seq, ",user_subvol_rm_allowed");
 719         if (btrfs_test_opt(root, ENOSPC_DEBUG))
 720                 seq_puts(seq, ",enospc_debug");
 721         if (btrfs_test_opt(root, AUTO_DEFRAG))
 722                 seq_puts(seq, ",autodefrag");
 723         if (btrfs_test_opt(root, INODE_MAP_CACHE))
 724                 seq_puts(seq, ",inode_cache");
 725         return 0;
 726 }
 727
 728 static int btrfs_test_super(struct super_block *s, void *data)
 729 {
 730         struct btrfs_root *test_root = data;
 731         struct btrfs_root *root = btrfs_sb(s);
 732
 733         /*
 734          * If this super block is going away, return false as it
 735          * can't match as an existing super block.
 736          */
 737         if (!atomic_read(&s->s_active))
 738                 return 0;
 739         return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
 740 }
 741
 742 static int btrfs_set_super(struct super_block *s, void *data)
 743 {
 744         s->s_fs_info = data;
 745
 746         return set_anon_super(s, data);
 747 }
 748
 749 /*
 750  * subvolumes are identified by ino 256
 751  */
 752 static inline int is_subvolume_inode(struct inode *inode)
 753 {
 754         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
 755                 return 1;
 756         return 0;
 757 }
 758
 759 /*
 760  * This will strip out the subvol=%s argument for an argument string and add
 761  * subvolid=0 to make sure we get the actual tree root for path walking to the
 762  * subvol we want.
 763  */
 764 static char *setup_root_args(char *args)
 765 {
 766         unsigned copied = 0;
 767         unsigned len = strlen(args) + 2;
 768         char *pos;
 769         char *ret;
 770
 771         /*
 772          * We need the same args as before, but minus
 773          *
 774          * subvol=a
 775          *
 776          * and add
 777          *
 778          * subvolid=0
 779          *
 780          * which is a difference of 2 characters, so we allocate strlen(args) +
 781          * 2 characters.
 782          */
 783         ret = kzalloc(len * sizeof(char), GFP_NOFS);
 784         if (!ret)
 785                 return NULL;
 786         pos = strstr(args, "subvol=");
 787
 788         /* This shouldn't happen, but just in case.. */
 789         if (!pos) {
 790                 kfree(ret);
 791                 return NULL;
 792         }
 793
 794         /*
 795          * The subvol=<> arg is not at the front of the string, copy everybody
 796          * up to that into ret.
 797          */
 798         if (pos != args) {
 799                 *pos = '\0';
 800                 strcpy(ret, args);
 801                 copied += strlen(args);
 802                 pos++;
 803         }
 804
 805         strncpy(ret + copied, "subvolid=0", len - copied);
 806
 807         /* Length of subvolid=0 */
 808         copied += 10;
 809
 810         /*
 811          * If there is no , after the subvol= option then we know there's no
 812          * other options and we can just return.
 813          */
 814         pos = strchr(pos, ',');
 815         if (!pos)
 816                 return ret;
 817
 818         /* Copy the rest of the arguments into our buffer */
 819         strncpy(ret + copied, pos, len - copied);
 820         copied += strlen(pos);
 821
 822         return ret;
 823 }
 824
 825 static struct dentry *mount_subvol(const char *subvol_name, int flags,
 826                                    const char *device_name, char *data)
 827 {
 828         struct super_block *s;
 829         struct dentry *root;
 830         struct vfsmount *mnt;
 831         struct mnt_namespace *ns_private;
 832         char *newargs;
 833         struct path path;
 834         int error;
 835
 836         newargs = setup_root_args(data);
 837         if (!newargs)
 838                 return ERR_PTR(-ENOMEM);
 839         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
 840                              newargs);
 841         kfree(newargs);
 842         if (IS_ERR(mnt))
 843                 return ERR_CAST(mnt);
 844
 845         ns_private = create_mnt_ns(mnt);
 846         if (IS_ERR(ns_private)) {
 847                 mntput(mnt);
 848                 return ERR_CAST(ns_private);
 849         }
 850
 851         /*
 852          * This will trigger the automount of the subvol so we can just
 853          * drop the mnt we have here and return the dentry that we
 854          * found.
 855          */
 856         error = vfs_path_lookup(mnt->mnt_root, mnt, subvol_name,
 857                                 LOOKUP_FOLLOW, &path);
 858         put_mnt_ns(ns_private);
 859         if (error)
 860                 return ERR_PTR(error);
 861
 862         if (!is_subvolume_inode(path.dentry->d_inode)) {
 863                 path_put(&path);
 864                 mntput(mnt);
 865                 error = -EINVAL;
 866                 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
 867                                 subvol_name);
 868                 return ERR_PTR(-EINVAL);
 869         }
 870
 871         /* Get a ref to the sb and the dentry we found and return it */
 872         s = path.mnt->mnt_sb;
 873         atomic_inc(&s->s_active);
 874         root = dget(path.dentry);
 875         path_put(&path);
 876         down_write(&s->s_umount);
 877
 878         return root;
 879 }
 880
 881 /*
 882  * Find a superblock for the given device / mount point.
 883  *
 884  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 885  *        for multiple device setup.  Make sure to keep it in sync.
 886  */
 887 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 888                 const char *device_name, void *data)
 889 {
 890         struct block_device *bdev = NULL;
 891         struct super_block *s;
 892         struct dentry *root;
 893         struct btrfs_fs_devices *fs_devices = 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                 kfree(subvol_name);
 909                 return ERR_PTR(error);
 910         }
 911
 912         if (subvol_name) {
 913                 root = mount_subvol(subvol_name, flags, device_name, data);
 914                 kfree(subvol_name);
 915                 return root;
 916         }
 917
 918         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
 919         if (error)
 920                 return ERR_PTR(error);
 921
 922         /*
 923          * Setup a dummy root and fs_info for test/set super.  This is because
 924          * we don't actually fill this stuff out until open_ctree, but we need
 925          * it for searching for existing supers, so this lets us do that and
 926          * then open_ctree will properly initialize everything later.
 927          */
 928         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
 929         if (!fs_info)
 930                 return ERR_PTR(-ENOMEM);
 931
 932         fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
 933         if (!fs_info->tree_root) {
 934                 error = -ENOMEM;
 935                 goto error_fs_info;
 936         }
 937         fs_info->tree_root->fs_info = fs_info;
 938         fs_info->fs_devices = fs_devices;
 939
 940         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
 941         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
 942         if (!fs_info->super_copy || !fs_info->super_for_commit) {
 943                 error = -ENOMEM;
 944                 goto error_fs_info;
 945         }
 946
 947         error = btrfs_open_devices(fs_devices, mode, fs_type);
 948         if (error)
 949                 goto error_fs_info;
 950
 951         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 952                 error = -EACCES;
 953                 goto error_close_devices;
 954         }
 955
 956         bdev = fs_devices->latest_bdev;
 957         s = sget(fs_type, btrfs_test_super, btrfs_set_super,
 958                  fs_info->tree_root);
 959         if (IS_ERR(s)) {
 960                 error = PTR_ERR(s);
 961                 goto error_close_devices;
 962         }
 963
 964         if (s->s_root) {
 965                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 966                         deactivate_locked_super(s);
 967                         error = -EBUSY;
 968                         goto error_close_devices;
 969                 }
 970
 971                 btrfs_close_devices(fs_devices);
 972                 free_fs_info(fs_info);
 973         } else {
 974                 char b[BDEVNAME_SIZE];
 975
 976                 s->s_flags = flags | MS_NOSEC;
 977                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 978                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 979                 error = btrfs_fill_super(s, fs_devices, data,
 980                                          flags & MS_SILENT ? 1 : 0);
 981                 if (error) {
 982                         deactivate_locked_super(s);
 983                         return ERR_PTR(error);
 984                 }
 985
 986                 s->s_flags |= MS_ACTIVE;
 987         }
 988
 989         root = get_default_root(s, subvol_objectid);
 990         if (IS_ERR(root)) {
 991                 deactivate_locked_super(s);
 992                 return root;
 993         }
 994
 995         return root;
 996
 997 error_close_devices:
 998         btrfs_close_devices(fs_devices);
 999 error_fs_info:
1000         free_fs_info(fs_info);
1001         return ERR_PTR(error);
1002 }
1003
1004 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1005 {
1006         struct btrfs_root *root = btrfs_sb(sb);
1007         int ret;
1008
1009         ret = btrfs_parse_options(root, data);
1010         if (ret)
1011                 return -EINVAL;
1012
1013         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1014                 return 0;
1015
1016         if (*flags & MS_RDONLY) {
1017                 sb->s_flags |= MS_RDONLY;
1018
1019                 ret =  btrfs_commit_super(root);
1020                 WARN_ON(ret);
1021         } else {
1022                 if (root->fs_info->fs_devices->rw_devices == 0)
1023                         return -EACCES;
1024
1025                 if (btrfs_super_log_root(root->fs_info->super_copy) != 0)
1026                         return -EINVAL;
1027
1028                 ret = btrfs_cleanup_fs_roots(root->fs_info);
1029                 WARN_ON(ret);
1030
1031                 /* recover relocation */
1032                 ret = btrfs_recover_relocation(root);
1033                 WARN_ON(ret);
1034
1035                 sb->s_flags &= ~MS_RDONLY;
1036         }
1037
1038         return 0;
1039 }
1040
1041 /* Used to sort the devices by max_avail(descending sort) */
1042 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1043                                        const void *dev_info2)
1044 {
1045         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1046             ((struct btrfs_device_info *)dev_info2)->max_avail)
1047                 return -1;
1048         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1049                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1050                 return 1;
1051         else
1052         return 0;
1053 }
1054
1055 /*
1056  * sort the devices by max_avail, in which max free extent size of each device
1057  * is stored.(Descending Sort)
1058  */
1059 static inline void btrfs_descending_sort_devices(
1060                                         struct btrfs_device_info *devices,
1061                                         size_t nr_devices)
1062 {
1063         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1064              btrfs_cmp_device_free_bytes, NULL);
1065 }
1066
1067 /*
1068  * The helper to calc the free space on the devices that can be used to store
1069  * file data.
1070  */
1071 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1072 {
1073         struct btrfs_fs_info *fs_info = root->fs_info;
1074         struct btrfs_device_info *devices_info;
1075         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1076         struct btrfs_device *device;
1077         u64 skip_space;
1078         u64 type;
1079         u64 avail_space;
1080         u64 used_space;
1081         u64 min_stripe_size;
1082         int min_stripes = 1;
1083         int i = 0, nr_devices;
1084         int ret;
1085
1086         nr_devices = fs_info->fs_devices->rw_devices;
1087         BUG_ON(!nr_devices);
1088
1089         devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1090                                GFP_NOFS);
1091         if (!devices_info)
1092                 return -ENOMEM;
1093
1094         /* calc min stripe number for data space alloction */
1095         type = btrfs_get_alloc_profile(root, 1);
1096         if (type & BTRFS_BLOCK_GROUP_RAID0)
1097                 min_stripes = 2;
1098         else if (type & BTRFS_BLOCK_GROUP_RAID1)
1099                 min_stripes = 2;
1100         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1101                 min_stripes = 4;
1102
1103         if (type & BTRFS_BLOCK_GROUP_DUP)
1104                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1105         else
1106                 min_stripe_size = BTRFS_STRIPE_LEN;
1107
1108         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
1109                 if (!device->in_fs_metadata)
1110                         continue;
1111
1112                 avail_space = device->total_bytes - device->bytes_used;
1113
1114                 /* align with stripe_len */
1115                 do_div(avail_space, BTRFS_STRIPE_LEN);
1116                 avail_space *= BTRFS_STRIPE_LEN;
1117
1118                 /*
1119                  * In order to avoid overwritting the superblock on the drive,
1120                  * btrfs starts at an offset of at least 1MB when doing chunk
1121                  * allocation.
1122                  */
1123                 skip_space = 1024 * 1024;
1124
1125                 /* user can set the offset in fs_info->alloc_start. */
1126                 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1127                     device->total_bytes)
1128                         skip_space = max(fs_info->alloc_start, skip_space);
1129
1130                 /*
1131                  * btrfs can not use the free space in [0, skip_space - 1],
1132                  * we must subtract it from the total. In order to implement
1133                  * it, we account the used space in this range first.
1134                  */
1135                 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1136                                                      &used_space);
1137                 if (ret) {
1138                         kfree(devices_info);
1139                         return ret;
1140                 }
1141
1142                 /* calc the free space in [0, skip_space - 1] */
1143                 skip_space -= used_space;
1144
1145                 /*
1146                  * we can use the free space in [0, skip_space - 1], subtract
1147                  * it from the total.
1148                  */
1149                 if (avail_space && avail_space >= skip_space)
1150                         avail_space -= skip_space;
1151                 else
1152                         avail_space = 0;
1153
1154                 if (avail_space < min_stripe_size)
1155                         continue;
1156
1157                 devices_info[i].dev = device;
1158                 devices_info[i].max_avail = avail_space;
1159
1160                 i++;
1161         }
1162
1163         nr_devices = i;
1164
1165         btrfs_descending_sort_devices(devices_info, nr_devices);
1166
1167         i = nr_devices - 1;
1168         avail_space = 0;
1169         while (nr_devices >= min_stripes) {
1170                 if (devices_info[i].max_avail >= min_stripe_size) {
1171                         int j;
1172                         u64 alloc_size;
1173
1174                         avail_space += devices_info[i].max_avail * min_stripes;
1175                         alloc_size = devices_info[i].max_avail;
1176                         for (j = i + 1 - min_stripes; j <= i; j++)
1177                                 devices_info[j].max_avail -= alloc_size;
1178                 }
1179                 i--;
1180                 nr_devices--;
1181         }
1182
1183         kfree(devices_info);
1184         *free_bytes = avail_space;
1185         return 0;
1186 }
1187
1188 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1189 {
1190         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
1191         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1192         struct list_head *head = &root->fs_info->space_info;
1193         struct btrfs_space_info *found;
1194         u64 total_used = 0;
1195         u64 total_free_data = 0;
1196         int bits = dentry->d_sb->s_blocksize_bits;
1197         __be32 *fsid = (__be32 *)root->fs_info->fsid;
1198         int ret;
1199
1200         /* holding chunk_muext to avoid allocating new chunks */
1201         mutex_lock(&root->fs_info->chunk_mutex);
1202         rcu_read_lock();
1203         list_for_each_entry_rcu(found, head, list) {
1204                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1205                         total_free_data += found->disk_total - found->disk_used;
1206                         total_free_data -=
1207                                 btrfs_account_ro_block_groups_free_space(found);
1208                 }
1209
1210                 total_used += found->disk_used;
1211         }
1212         rcu_read_unlock();
1213
1214         buf->f_namelen = BTRFS_NAME_LEN;
1215         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1216         buf->f_bfree = buf->f_blocks - (total_used >> bits);
1217         buf->f_bsize = dentry->d_sb->s_blocksize;
1218         buf->f_type = BTRFS_SUPER_MAGIC;
1219         buf->f_bavail = total_free_data;
1220         ret = btrfs_calc_avail_data_space(root, &total_free_data);
1221         if (ret) {
1222                 mutex_unlock(&root->fs_info->chunk_mutex);
1223                 return ret;
1224         }
1225         buf->f_bavail += total_free_data;
1226         buf->f_bavail = buf->f_bavail >> bits;
1227         mutex_unlock(&root->fs_info->chunk_mutex);
1228
1229         /* We treat it as constant endianness (it doesn't matter _which_)
1230            because we want the fsid to come out the same whether mounted
1231            on a big-endian or little-endian host */
1232         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1233         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1234         /* Mask in the root object ID too, to disambiguate subvols */
1235         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1236         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1237
1238         return 0;
1239 }
1240
1241 static struct file_system_type btrfs_fs_type = {
1242         .owner          = THIS_MODULE,
1243         .name           = "btrfs",
1244         .mount          = btrfs_mount,
1245         .kill_sb        = kill_anon_super,
1246         .fs_flags       = FS_REQUIRES_DEV,
1247 };
1248
1249 /*
1250  * used by btrfsctl to scan devices when no FS is mounted
1251  */
1252 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1253                                 unsigned long arg)
1254 {
1255         struct btrfs_ioctl_vol_args *vol;
1256         struct btrfs_fs_devices *fs_devices;
1257         int ret = -ENOTTY;
1258
1259         if (!capable(CAP_SYS_ADMIN))
1260                 return -EPERM;
1261
1262         vol = memdup_user((void __user *)arg, sizeof(*vol));
1263         if (IS_ERR(vol))
1264                 return PTR_ERR(vol);
1265
1266         switch (cmd) {
1267         case BTRFS_IOC_SCAN_DEV:
1268                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1269                                             &btrfs_fs_type, &fs_devices);
1270                 break;
1271         }
1272
1273         kfree(vol);
1274         return ret;
1275 }
1276
1277 static int btrfs_freeze(struct super_block *sb)
1278 {
1279         struct btrfs_root *root = btrfs_sb(sb);
1280         mutex_lock(&root->fs_info->transaction_kthread_mutex);
1281         mutex_lock(&root->fs_info->cleaner_mutex);
1282         return 0;
1283 }
1284
1285 static int btrfs_unfreeze(struct super_block *sb)
1286 {
1287         struct btrfs_root *root = btrfs_sb(sb);
1288         mutex_unlock(&root->fs_info->cleaner_mutex);
1289         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1290         return 0;
1291 }
1292
1293 static const struct super_operations btrfs_super_ops = {
1294         .drop_inode     = btrfs_drop_inode,
1295         .evict_inode    = btrfs_evict_inode,
1296         .put_super      = btrfs_put_super,
1297         .sync_fs        = btrfs_sync_fs,
1298         .show_options   = btrfs_show_options,
1299         .write_inode    = btrfs_write_inode,
1300         .dirty_inode    = btrfs_dirty_inode,
1301         .alloc_inode    = btrfs_alloc_inode,
1302         .destroy_inode  = btrfs_destroy_inode,
1303         .statfs         = btrfs_statfs,
1304         .remount_fs     = btrfs_remount,
1305         .freeze_fs      = btrfs_freeze,
1306         .unfreeze_fs    = btrfs_unfreeze,
1307 };
1308
1309 static const struct file_operations btrfs_ctl_fops = {
1310         .unlocked_ioctl  = btrfs_control_ioctl,
1311         .compat_ioctl = btrfs_control_ioctl,
1312         .owner   = THIS_MODULE,
1313         .llseek = noop_llseek,
1314 };
1315
1316 static struct miscdevice btrfs_misc = {
1317         .minor          = BTRFS_MINOR,
1318         .name           = "btrfs-control",
1319         .fops           = &btrfs_ctl_fops
1320 };
1321
1322 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1323 MODULE_ALIAS("devname:btrfs-control");
1324
1325 static int btrfs_interface_init(void)
1326 {
1327         return misc_register(&btrfs_misc);
1328 }
1329
1330 static void btrfs_interface_exit(void)
1331 {
1332         if (misc_deregister(&btrfs_misc) < 0)
1333                 printk(KERN_INFO "misc_deregister failed for control device");
1334 }
1335
1336 static int __init init_btrfs_fs(void)
1337 {
1338         int err;
1339
1340         err = btrfs_init_sysfs();
1341         if (err)
1342                 return err;
1343
1344         err = btrfs_init_compress();
1345         if (err)
1346                 goto free_sysfs;
1347
1348         err = btrfs_init_cachep();
1349         if (err)
1350                 goto free_compress;
1351
1352         err = extent_io_init();
1353         if (err)
1354                 goto free_cachep;
1355
1356         err = extent_map_init();
1357         if (err)
1358                 goto free_extent_io;
1359
1360         err = btrfs_delayed_inode_init();
1361         if (err)
1362                 goto free_extent_map;
1363
1364         err = btrfs_interface_init();
1365         if (err)
1366                 goto free_delayed_inode;
1367
1368         err = register_filesystem(&btrfs_fs_type);
1369         if (err)
1370                 goto unregister_ioctl;
1371
1372         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1373         return 0;
1374
1375 unregister_ioctl:
1376         btrfs_interface_exit();
1377 free_delayed_inode:
1378         btrfs_delayed_inode_exit();
1379 free_extent_map:
1380         extent_map_exit();
1381 free_extent_io:
1382         extent_io_exit();
1383 free_cachep:
1384         btrfs_destroy_cachep();
1385 free_compress:
1386         btrfs_exit_compress();
1387 free_sysfs:
1388         btrfs_exit_sysfs();
1389         return err;
1390 }
1391
1392 static void __exit exit_btrfs_fs(void)
1393 {
1394         btrfs_destroy_cachep();
1395         btrfs_delayed_inode_exit();
1396         extent_map_exit();
1397         extent_io_exit();
1398         btrfs_interface_exit();
1399         unregister_filesystem(&btrfs_fs_type);
1400         btrfs_exit_sysfs();
1401         btrfs_cleanup_fs_uuids();
1402         btrfs_exit_compress();
1403 }
1404
1405 module_init(init_btrfs_fs)
1406 module_exit(exit_btrfs_fs)
1407
1408 MODULE_LICENSE("GPL");