fs/btrfs/super.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/fs.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/highmem.h>
  25 #include <linux/time.h>
  26 #include <linux/init.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mount.h>
  31 #include <linux/mpage.h>
  32 #include <linux/swap.h>
  33 #include <linux/writeback.h>
  34 #include <linux/statfs.h>
  35 #include <linux/compat.h>
  36 #include <linux/parser.h>
  37 #include <linux/ctype.h>
  38 #include <linux/namei.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/magic.h>
  41 #include <linux/slab.h>
  42 #include <linux/cleancache.h>
  43 #include <linux/mnt_namespace.h>
  44 #include <linux/ratelimit.h>
  45 #include "compat.h"
  46 #include "delayed-inode.h"
  47 #include "ctree.h"
  48 #include "disk-io.h"
  49 #include "transaction.h"
  50 #include "btrfs_inode.h"
  51 #include "ioctl.h"
  52 #include "print-tree.h"
  53 #include "xattr.h"
  54 #include "volumes.h"
  55 #include "version.h"
  56 #include "export.h"
  57 #include "compression.h"
  58
  59 #define CREATE_TRACE_POINTS
  60 #include <trace/events/btrfs.h>
  61
  62 static const struct super_operations btrfs_super_ops;
  63 static struct file_system_type btrfs_fs_type;
  64
  65 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
  66                                       char nbuf[16])
  67 {
  68         char *errstr = NULL;
  69
  70         switch (errno) {
  71         case -EIO:
  72                 errstr = "IO failure";
  73                 break;
  74         case -ENOMEM:
  75                 errstr = "Out of memory";
  76                 break;
  77         case -EROFS:
  78                 errstr = "Readonly filesystem";
  79                 break;
  80         default:
  81                 if (nbuf) {
  82                         if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
  83                                 errstr = nbuf;
  84                 }
  85                 break;
  86         }
  87
  88         return errstr;
  89 }
  90
  91 static void __save_error_info(struct btrfs_fs_info *fs_info)
  92 {
  93         /*
  94          * today we only save the error info into ram.  Long term we'll
  95          * also send it down to the disk
  96          */
  97         fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
  98 }
  99
 100 /* NOTE:
 101  *      We move write_super stuff at umount in order to avoid deadlock
 102  *      for umount hold all lock.
 103  */
 104 static void save_error_info(struct btrfs_fs_info *fs_info)
 105 {
 106         __save_error_info(fs_info);
 107 }
 108
 109 /* btrfs handle error by forcing the filesystem readonly */
 110 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 111 {
 112         struct super_block *sb = fs_info->sb;
 113
 114         if (sb->s_flags & MS_RDONLY)
 115                 return;
 116
 117         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
 118                 sb->s_flags |= MS_RDONLY;
 119                 printk(KERN_INFO "btrfs is forced readonly\n");
 120         }
 121 }
 122
 123 /*
 124  * __btrfs_std_error decodes expected errors from the caller and
 125  * invokes the approciate error response.
 126  */
 127 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 128                      unsigned int line, int errno)
 129 {
 130         struct super_block *sb = fs_info->sb;
 131         char nbuf[16];
 132         const char *errstr;
 133
 134         /*
 135          * Special case: if the error is EROFS, and we're already
 136          * under MS_RDONLY, then it is safe here.
 137          */
 138         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 139                 return;
 140
 141         errstr = btrfs_decode_error(fs_info, errno, nbuf);
 142         printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
 143                 sb->s_id, function, line, errstr);
 144         save_error_info(fs_info);
 145
 146         btrfs_handle_error(fs_info);
 147 }
 148
 149 static void btrfs_put_super(struct super_block *sb)
 150 {
 151         struct btrfs_root *root = btrfs_sb(sb);
 152         int ret;
 153
 154         ret = close_ctree(root);
 155         sb->s_fs_info = NULL;
 156
 157         (void)ret; /* FIXME: need to fix VFS to return error? */
 158 }
 159
 160 enum {
 161         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 162         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 163         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 164         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 165         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 166         Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
 167         Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
 168         Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
 169         Opt_err,
 170 };
 171
 172 static match_table_t tokens = {
 173         {Opt_degraded, "degraded"},
 174         {Opt_subvol, "subvol=%s"},
 175         {Opt_subvolid, "subvolid=%d"},
 176         {Opt_device, "device=%s"},
 177         {Opt_nodatasum, "nodatasum"},
 178         {Opt_nodatacow, "nodatacow"},
 179         {Opt_nobarrier, "nobarrier"},
 180         {Opt_max_inline, "max_inline=%s"},
 181         {Opt_alloc_start, "alloc_start=%s"},
 182         {Opt_thread_pool, "thread_pool=%d"},
 183         {Opt_compress, "compress"},
 184         {Opt_compress_type, "compress=%s"},
 185         {Opt_compress_force, "compress-force"},
 186         {Opt_compress_force_type, "compress-force=%s"},
 187         {Opt_ssd, "ssd"},
 188         {Opt_ssd_spread, "ssd_spread"},
 189         {Opt_nossd, "nossd"},
 190         {Opt_noacl, "noacl"},
 191         {Opt_notreelog, "notreelog"},
 192         {Opt_flushoncommit, "flushoncommit"},
 193         {Opt_ratio, "metadata_ratio=%d"},
 194         {Opt_discard, "discard"},
 195         {Opt_space_cache, "space_cache"},
 196         {Opt_clear_cache, "clear_cache"},
 197         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 198         {Opt_enospc_debug, "enospc_debug"},
 199         {Opt_subvolrootid, "subvolrootid=%d"},
 200         {Opt_defrag, "autodefrag"},
 201         {Opt_inode_cache, "inode_cache"},
 202         {Opt_no_space_cache, "nospace_cache"},
 203         {Opt_recovery, "recovery"},
 204         {Opt_skip_balance, "skip_balance"},
 205         {Opt_err, NULL},
 206 };
 207
 208 /*
 209  * Regular mount options parser.  Everything that is needed only when
 210  * reading in a new superblock is parsed here.
 211  */
 212 int btrfs_parse_options(struct btrfs_root *root, char *options)
 213 {
 214         struct btrfs_fs_info *info = root->fs_info;
 215         substring_t args[MAX_OPT_ARGS];
 216         char *p, *num, *orig = NULL;
 217         u64 cache_gen;
 218         int intarg;
 219         int ret = 0;
 220         char *compress_type;
 221         bool compress_force = false;
 222
 223         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 224         if (cache_gen)
 225                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 226
 227         if (!options)
 228                 goto out;
 229
 230         /*
 231          * strsep changes the string, duplicate it because parse_options
 232          * gets called twice
 233          */
 234         options = kstrdup(options, GFP_NOFS);
 235         if (!options)
 236                 return -ENOMEM;
 237
 238         orig = options;
 239
 240         while ((p = strsep(&options, ",")) != NULL) {
 241                 int token;
 242                 if (!*p)
 243                         continue;
 244
 245                 token = match_token(p, tokens, args);
 246                 switch (token) {
 247                 case Opt_degraded:
 248                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 249                         btrfs_set_opt(info->mount_opt, DEGRADED);
 250                         break;
 251                 case Opt_subvol:
 252                 case Opt_subvolid:
 253                 case Opt_subvolrootid:
 254                 case Opt_device:
 255                         /*
 256                          * These are parsed by btrfs_parse_early_options
 257                          * and can be happily ignored here.
 258                          */
 259                         break;
 260                 case Opt_nodatasum:
 261                         printk(KERN_INFO "btrfs: setting nodatasum\n");
 262                         btrfs_set_opt(info->mount_opt, NODATASUM);
 263                         break;
 264                 case Opt_nodatacow:
 265                         printk(KERN_INFO "btrfs: setting nodatacow\n");
 266                         btrfs_set_opt(info->mount_opt, NODATACOW);
 267                         btrfs_set_opt(info->mount_opt, NODATASUM);
 268                         break;
 269                 case Opt_compress_force:
 270                 case Opt_compress_force_type:
 271                         compress_force = true;
 272                 case Opt_compress:
 273                 case Opt_compress_type:
 274                         if (token == Opt_compress ||
 275                             token == Opt_compress_force ||
 276                             strcmp(args[0].from, "zlib") == 0) {
 277                                 compress_type = "zlib";
 278                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 279                         } else if (strcmp(args[0].from, "lzo") == 0) {
 280                                 compress_type = "lzo";
 281                                 info->compress_type = BTRFS_COMPRESS_LZO;
 282                         } else {
 283                                 ret = -EINVAL;
 284                                 goto out;
 285                         }
 286
 287                         btrfs_set_opt(info->mount_opt, COMPRESS);
 288                         if (compress_force) {
 289                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 290                                 pr_info("btrfs: force %s compression\n",
 291                                         compress_type);
 292                         } else
 293                                 pr_info("btrfs: use %s compression\n",
 294                                         compress_type);
 295                         break;
 296                 case Opt_ssd:
 297                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 298                         btrfs_set_opt(info->mount_opt, SSD);
 299                         break;
 300                 case Opt_ssd_spread:
 301                         printk(KERN_INFO "btrfs: use spread ssd "
 302                                "allocation scheme\n");
 303                         btrfs_set_opt(info->mount_opt, SSD);
 304                         btrfs_set_opt(info->mount_opt, SSD_SPREAD);
 305                         break;
 306                 case Opt_nossd:
 307                         printk(KERN_INFO "btrfs: not using ssd allocation "
 308                                "scheme\n");
 309                         btrfs_set_opt(info->mount_opt, NOSSD);
 310                         btrfs_clear_opt(info->mount_opt, SSD);
 311                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
 312                         break;
 313                 case Opt_nobarrier:
 314                         printk(KERN_INFO "btrfs: turning off barriers\n");
 315                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 316                         break;
 317                 case Opt_thread_pool:
 318                         intarg = 0;
 319                         match_int(&args[0], &intarg);
 320                         if (intarg) {
 321                                 info->thread_pool_size = intarg;
 322                                 printk(KERN_INFO "btrfs: thread pool %d\n",
 323                                        info->thread_pool_size);
 324                         }
 325                         break;
 326                 case Opt_max_inline:
 327                         num = match_strdup(&args[0]);
 328                         if (num) {
 329                                 info->max_inline = memparse(num, NULL);
 330                                 kfree(num);
 331
 332                                 if (info->max_inline) {
 333                                         info->max_inline = max_t(u64,
 334                                                 info->max_inline,
 335                                                 root->sectorsize);
 336                                 }
 337                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 338                                         (unsigned long long)info->max_inline);
 339                         }
 340                         break;
 341                 case Opt_alloc_start:
 342                         num = match_strdup(&args[0]);
 343                         if (num) {
 344                                 info->alloc_start = memparse(num, NULL);
 345                                 kfree(num);
 346                                 printk(KERN_INFO
 347                                         "btrfs: allocations start at %llu\n",
 348                                         (unsigned long long)info->alloc_start);
 349                         }
 350                         break;
 351                 case Opt_noacl:
 352                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 353                         break;
 354                 case Opt_notreelog:
 355                         printk(KERN_INFO "btrfs: disabling tree log\n");
 356                         btrfs_set_opt(info->mount_opt, NOTREELOG);
 357                         break;
 358                 case Opt_flushoncommit:
 359                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
 360                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
 361                         break;
 362                 case Opt_ratio:
 363                         intarg = 0;
 364                         match_int(&args[0], &intarg);
 365                         if (intarg) {
 366                                 info->metadata_ratio = intarg;
 367                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
 368                                        info->metadata_ratio);
 369                         }
 370                         break;
 371                 case Opt_discard:
 372                         btrfs_set_opt(info->mount_opt, DISCARD);
 373                         break;
 374                 case Opt_space_cache:
 375                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 376                         break;
 377                 case Opt_no_space_cache:
 378                         printk(KERN_INFO "btrfs: disabling disk space caching\n");
 379                         btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
 380                         break;
 381                 case Opt_inode_cache:
 382                         printk(KERN_INFO "btrfs: enabling inode map caching\n");
 383                         btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
 384                         break;
 385                 case Opt_clear_cache:
 386                         printk(KERN_INFO "btrfs: force clearing of disk cache\n");
 387                         btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
 388                         break;
 389                 case Opt_user_subvol_rm_allowed:
 390                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 391                         break;
 392                 case Opt_enospc_debug:
 393                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 394                         break;
 395                 case Opt_defrag:
 396                         printk(KERN_INFO "btrfs: enabling auto defrag");
 397                         btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
 398                         break;
 399                 case Opt_recovery:
 400                         printk(KERN_INFO "btrfs: enabling auto recovery");
 401                         btrfs_set_opt(info->mount_opt, RECOVERY);
 402                         break;
 403                 case Opt_skip_balance:
 404                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 405                         break;
 406                 case Opt_err:
 407                         printk(KERN_INFO "btrfs: unrecognized mount option "
 408                                "'%s'\n", p);
 409                         ret = -EINVAL;
 410                         goto out;
 411                 default:
 412                         break;
 413                 }
 414         }
 415 out:
 416         if (!ret && btrfs_test_opt(root, SPACE_CACHE))
 417                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
 418         kfree(orig);
 419         return ret;
 420 }
 421
 422 /*
 423  * Parse mount options that are required early in the mount process.
 424  *
 425  * All other options will be parsed on much later in the mount process and
 426  * only when we need to allocate a new super block.
 427  */
 428 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 429                 void *holder, char **subvol_name, u64 *subvol_objectid,
 430                 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
 431 {
 432         substring_t args[MAX_OPT_ARGS];
 433         char *device_name, *opts, *orig, *p;
 434         int error = 0;
 435         int intarg;
 436
 437         if (!options)
 438                 return 0;
 439
 440         /*
 441          * strsep changes the string, duplicate it because parse_options
 442          * gets called twice
 443          */
 444         opts = kstrdup(options, GFP_KERNEL);
 445         if (!opts)
 446                 return -ENOMEM;
 447         orig = opts;
 448
 449         while ((p = strsep(&opts, ",")) != NULL) {
 450                 int token;
 451                 if (!*p)
 452                         continue;
 453
 454                 token = match_token(p, tokens, args);
 455                 switch (token) {
 456                 case Opt_subvol:
 457                         kfree(*subvol_name);
 458                         *subvol_name = match_strdup(&args[0]);
 459                         break;
 460                 case Opt_subvolid:
 461                         intarg = 0;
 462                         error = match_int(&args[0], &intarg);
 463                         if (!error) {
 464                                 /* we want the original fs_tree */
 465                                 if (!intarg)
 466                                         *subvol_objectid =
 467                                                 BTRFS_FS_TREE_OBJECTID;
 468                                 else
 469                                         *subvol_objectid = intarg;
 470                         }
 471                         break;
 472                 case Opt_subvolrootid:
 473                         intarg = 0;
 474                         error = match_int(&args[0], &intarg);
 475                         if (!error) {
 476                                 /* we want the original fs_tree */
 477                                 if (!intarg)
 478                                         *subvol_rootid =
 479                                                 BTRFS_FS_TREE_OBJECTID;
 480                                 else
 481                                         *subvol_rootid = intarg;
 482                         }
 483                         break;
 484                 case Opt_device:
 485                         device_name = match_strdup(&args[0]);
 486                         if (!device_name) {
 487                                 error = -ENOMEM;
 488                                 goto out;
 489                         }
 490                         error = btrfs_scan_one_device(device_name,
 491                                         flags, holder, fs_devices);
 492                         kfree(device_name);
 493                         if (error)
 494                                 goto out;
 495                         break;
 496                 default:
 497                         break;
 498                 }
 499         }
 500
 501 out:
 502         kfree(orig);
 503         return error;
 504 }
 505
 506 static struct dentry *get_default_root(struct super_block *sb,
 507                                        u64 subvol_objectid)
 508 {
 509         struct btrfs_root *root = sb->s_fs_info;
 510         struct btrfs_root *new_root;
 511         struct btrfs_dir_item *di;
 512         struct btrfs_path *path;
 513         struct btrfs_key location;
 514         struct inode *inode;
 515         u64 dir_id;
 516         int new = 0;
 517
 518         /*
 519          * We have a specific subvol we want to mount, just setup location and
 520          * go look up the root.
 521          */
 522         if (subvol_objectid) {
 523                 location.objectid = subvol_objectid;
 524                 location.type = BTRFS_ROOT_ITEM_KEY;
 525                 location.offset = (u64)-1;
 526                 goto find_root;
 527         }
 528
 529         path = btrfs_alloc_path();
 530         if (!path)
 531                 return ERR_PTR(-ENOMEM);
 532         path->leave_spinning = 1;
 533
 534         /*
 535          * Find the "default" dir item which points to the root item that we
 536          * will mount by default if we haven't been given a specific subvolume
 537          * to mount.
 538          */
 539         dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
 540         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
 541         if (IS_ERR(di)) {
 542                 btrfs_free_path(path);
 543                 return ERR_CAST(di);
 544         }
 545         if (!di) {
 546                 /*
 547                  * Ok the default dir item isn't there.  This is weird since
 548                  * it's always been there, but don't freak out, just try and
 549                  * mount to root most subvolume.
 550                  */
 551                 btrfs_free_path(path);
 552                 dir_id = BTRFS_FIRST_FREE_OBJECTID;
 553                 new_root = root->fs_info->fs_root;
 554                 goto setup_root;
 555         }
 556
 557         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
 558         btrfs_free_path(path);
 559
 560 find_root:
 561         new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
 562         if (IS_ERR(new_root))
 563                 return ERR_CAST(new_root);
 564
 565         if (btrfs_root_refs(&new_root->root_item) == 0)
 566                 return ERR_PTR(-ENOENT);
 567
 568         dir_id = btrfs_root_dirid(&new_root->root_item);
 569 setup_root:
 570         location.objectid = dir_id;
 571         location.type = BTRFS_INODE_ITEM_KEY;
 572         location.offset = 0;
 573
 574         inode = btrfs_iget(sb, &location, new_root, &new);
 575         if (IS_ERR(inode))
 576                 return ERR_CAST(inode);
 577
 578         /*
 579          * If we're just mounting the root most subvol put the inode and return
 580          * a reference to the dentry.  We will have already gotten a reference
 581          * to the inode in btrfs_fill_super so we're good to go.
 582          */
 583         if (!new && sb->s_root->d_inode == inode) {
 584                 iput(inode);
 585                 return dget(sb->s_root);
 586         }
 587
 588         return d_obtain_alias(inode);
 589 }
 590
 591 static int btrfs_fill_super(struct super_block *sb,
 592                             struct btrfs_fs_devices *fs_devices,
 593                             void *data, int silent)
 594 {
 595         struct inode *inode;
 596         struct dentry *root_dentry;
 597         struct btrfs_root *tree_root;
 598         struct btrfs_key key;
 599         int err;
 600
 601         sb->s_maxbytes = MAX_LFS_FILESIZE;
 602         sb->s_magic = BTRFS_SUPER_MAGIC;
 603         sb->s_op = &btrfs_super_ops;
 604         sb->s_d_op = &btrfs_dentry_operations;
 605         sb->s_export_op = &btrfs_export_ops;
 606         sb->s_xattr = btrfs_xattr_handlers;
 607         sb->s_time_gran = 1;
 608 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 609         sb->s_flags |= MS_POSIXACL;
 610 #endif
 611
 612         tree_root = open_ctree(sb, fs_devices, (char *)data);
 613
 614         if (IS_ERR(tree_root)) {
 615                 printk("btrfs: open_ctree failed\n");
 616                 return PTR_ERR(tree_root);
 617         }
 618         sb->s_fs_info = tree_root;
 619
 620         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 621         key.type = BTRFS_INODE_ITEM_KEY;
 622         key.offset = 0;
 623         inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
 624         if (IS_ERR(inode)) {
 625                 err = PTR_ERR(inode);
 626                 goto fail_close;
 627         }
 628
 629         root_dentry = d_alloc_root(inode);
 630         if (!root_dentry) {
 631                 iput(inode);
 632                 err = -ENOMEM;
 633                 goto fail_close;
 634         }
 635
 636         sb->s_root = root_dentry;
 637
 638         save_mount_options(sb, data);
 639         cleancache_init_fs(sb);
 640         return 0;
 641
 642 fail_close:
 643         close_ctree(tree_root);
 644         return err;
 645 }
 646
 647 int btrfs_sync_fs(struct super_block *sb, int wait)
 648 {
 649         struct btrfs_trans_handle *trans;
 650         struct btrfs_root *root = btrfs_sb(sb);
 651         int ret;
 652
 653         trace_btrfs_sync_fs(wait);
 654
 655         if (!wait) {
 656                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 657                 return 0;
 658         }
 659
 660         btrfs_start_delalloc_inodes(root, 0);
 661         btrfs_wait_ordered_extents(root, 0, 0);
 662
 663         trans = btrfs_start_transaction(root, 0);
 664         if (IS_ERR(trans))
 665                 return PTR_ERR(trans);
 666         ret = btrfs_commit_transaction(trans, root);
 667         return ret;
 668 }
 669
 670 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 671 {
 672         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
 673         struct btrfs_fs_info *info = root->fs_info;
 674         char *compress_type;
 675
 676         if (btrfs_test_opt(root, DEGRADED))
 677                 seq_puts(seq, ",degraded");
 678         if (btrfs_test_opt(root, NODATASUM))
 679                 seq_puts(seq, ",nodatasum");
 680         if (btrfs_test_opt(root, NODATACOW))
 681                 seq_puts(seq, ",nodatacow");
 682         if (btrfs_test_opt(root, NOBARRIER))
 683                 seq_puts(seq, ",nobarrier");
 684         if (info->max_inline != 8192 * 1024)
 685                 seq_printf(seq, ",max_inline=%llu",
 686                            (unsigned long long)info->max_inline);
 687         if (info->alloc_start != 0)
 688                 seq_printf(seq, ",alloc_start=%llu",
 689                            (unsigned long long)info->alloc_start);
 690         if (info->thread_pool_size !=  min_t(unsigned long,
 691                                              num_online_cpus() + 2, 8))
 692                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 693         if (btrfs_test_opt(root, COMPRESS)) {
 694                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
 695                         compress_type = "zlib";
 696                 else
 697                         compress_type = "lzo";
 698                 if (btrfs_test_opt(root, FORCE_COMPRESS))
 699                         seq_printf(seq, ",compress-force=%s", compress_type);
 700                 else
 701                         seq_printf(seq, ",compress=%s", compress_type);
 702         }
 703         if (btrfs_test_opt(root, NOSSD))
 704                 seq_puts(seq, ",nossd");
 705         if (btrfs_test_opt(root, SSD_SPREAD))
 706                 seq_puts(seq, ",ssd_spread");
 707         else if (btrfs_test_opt(root, SSD))
 708                 seq_puts(seq, ",ssd");
 709         if (btrfs_test_opt(root, NOTREELOG))
 710                 seq_puts(seq, ",notreelog");
 711         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 712                 seq_puts(seq, ",flushoncommit");
 713         if (btrfs_test_opt(root, DISCARD))
 714                 seq_puts(seq, ",discard");
 715         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 716                 seq_puts(seq, ",noacl");
 717         if (btrfs_test_opt(root, SPACE_CACHE))
 718                 seq_puts(seq, ",space_cache");
 719         else
 720                 seq_puts(seq, ",nospace_cache");
 721         if (btrfs_test_opt(root, CLEAR_CACHE))
 722                 seq_puts(seq, ",clear_cache");
 723         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
 724                 seq_puts(seq, ",user_subvol_rm_allowed");
 725         if (btrfs_test_opt(root, ENOSPC_DEBUG))
 726                 seq_puts(seq, ",enospc_debug");
 727         if (btrfs_test_opt(root, AUTO_DEFRAG))
 728                 seq_puts(seq, ",autodefrag");
 729         if (btrfs_test_opt(root, INODE_MAP_CACHE))
 730                 seq_puts(seq, ",inode_cache");
 731         if (btrfs_test_opt(root, SKIP_BALANCE))
 732                 seq_puts(seq, ",skip_balance");
 733         return 0;
 734 }
 735
 736 static int btrfs_test_super(struct super_block *s, void *data)
 737 {
 738         struct btrfs_root *test_root = data;
 739         struct btrfs_root *root = btrfs_sb(s);
 740
 741         /*
 742          * If this super block is going away, return false as it
 743          * can't match as an existing super block.
 744          */
 745         if (!atomic_read(&s->s_active))
 746                 return 0;
 747         return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
 748 }
 749
 750 static int btrfs_set_super(struct super_block *s, void *data)
 751 {
 752         s->s_fs_info = data;
 753
 754         return set_anon_super(s, data);
 755 }
 756
 757 /*
 758  * subvolumes are identified by ino 256
 759  */
 760 static inline int is_subvolume_inode(struct inode *inode)
 761 {
 762         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
 763                 return 1;
 764         return 0;
 765 }
 766
 767 /*
 768  * This will strip out the subvol=%s argument for an argument string and add
 769  * subvolid=0 to make sure we get the actual tree root for path walking to the
 770  * subvol we want.
 771  */
 772 static char *setup_root_args(char *args)
 773 {
 774         unsigned copied = 0;
 775         unsigned len = strlen(args) + 2;
 776         char *pos;
 777         char *ret;
 778
 779         /*
 780          * We need the same args as before, but minus
 781          *
 782          * subvol=a
 783          *
 784          * and add
 785          *
 786          * subvolid=0
 787          *
 788          * which is a difference of 2 characters, so we allocate strlen(args) +
 789          * 2 characters.
 790          */
 791         ret = kzalloc(len * sizeof(char), GFP_NOFS);
 792         if (!ret)
 793                 return NULL;
 794         pos = strstr(args, "subvol=");
 795
 796         /* This shouldn't happen, but just in case.. */
 797         if (!pos) {
 798                 kfree(ret);
 799                 return NULL;
 800         }
 801
 802         /*
 803          * The subvol=<> arg is not at the front of the string, copy everybody
 804          * up to that into ret.
 805          */
 806         if (pos != args) {
 807                 *pos = '\0';
 808                 strcpy(ret, args);
 809                 copied += strlen(args);
 810                 pos++;
 811         }
 812
 813         strncpy(ret + copied, "subvolid=0", len - copied);
 814
 815         /* Length of subvolid=0 */
 816         copied += 10;
 817
 818         /*
 819          * If there is no , after the subvol= option then we know there's no
 820          * other options and we can just return.
 821          */
 822         pos = strchr(pos, ',');
 823         if (!pos)
 824                 return ret;
 825
 826         /* Copy the rest of the arguments into our buffer */
 827         strncpy(ret + copied, pos, len - copied);
 828         copied += strlen(pos);
 829
 830         return ret;
 831 }
 832
 833 static struct dentry *mount_subvol(const char *subvol_name, int flags,
 834                                    const char *device_name, char *data)
 835 {
 836         struct dentry *root;
 837         struct vfsmount *mnt;
 838         char *newargs;
 839
 840         newargs = setup_root_args(data);
 841         if (!newargs)
 842                 return ERR_PTR(-ENOMEM);
 843         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
 844                              newargs);
 845         kfree(newargs);
 846         if (IS_ERR(mnt))
 847                 return ERR_CAST(mnt);
 848
 849         root = mount_subtree(mnt, subvol_name);
 850
 851         if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
 852                 struct super_block *s = root->d_sb;
 853                 dput(root);
 854                 root = ERR_PTR(-EINVAL);
 855                 deactivate_locked_super(s);
 856                 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
 857                                 subvol_name);
 858         }
 859
 860         return root;
 861 }
 862
 863 /*
 864  * Find a superblock for the given device / mount point.
 865  *
 866  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 867  *        for multiple device setup.  Make sure to keep it in sync.
 868  */
 869 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 870                 const char *device_name, void *data)
 871 {
 872         struct block_device *bdev = NULL;
 873         struct super_block *s;
 874         struct dentry *root;
 875         struct btrfs_fs_devices *fs_devices = NULL;
 876         struct btrfs_fs_info *fs_info = NULL;
 877         fmode_t mode = FMODE_READ;
 878         char *subvol_name = NULL;
 879         u64 subvol_objectid = 0;
 880         u64 subvol_rootid = 0;
 881         int error = 0;
 882
 883         if (!(flags & MS_RDONLY))
 884                 mode |= FMODE_WRITE;
 885
 886         error = btrfs_parse_early_options(data, mode, fs_type,
 887                                           &subvol_name, &subvol_objectid,
 888                                           &subvol_rootid, &fs_devices);
 889         if (error) {
 890                 kfree(subvol_name);
 891                 return ERR_PTR(error);
 892         }
 893
 894         if (subvol_name) {
 895                 root = mount_subvol(subvol_name, flags, device_name, data);
 896                 kfree(subvol_name);
 897                 return root;
 898         }
 899
 900         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
 901         if (error)
 902                 return ERR_PTR(error);
 903
 904         /*
 905          * Setup a dummy root and fs_info for test/set super.  This is because
 906          * we don't actually fill this stuff out until open_ctree, but we need
 907          * it for searching for existing supers, so this lets us do that and
 908          * then open_ctree will properly initialize everything later.
 909          */
 910         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
 911         if (!fs_info)
 912                 return ERR_PTR(-ENOMEM);
 913
 914         fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
 915         if (!fs_info->tree_root) {
 916                 error = -ENOMEM;
 917                 goto error_fs_info;
 918         }
 919         fs_info->tree_root->fs_info = fs_info;
 920         fs_info->fs_devices = fs_devices;
 921
 922         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
 923         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
 924         if (!fs_info->super_copy || !fs_info->super_for_commit) {
 925                 error = -ENOMEM;
 926                 goto error_fs_info;
 927         }
 928
 929         error = btrfs_open_devices(fs_devices, mode, fs_type);
 930         if (error)
 931                 goto error_fs_info;
 932
 933         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 934                 error = -EACCES;
 935                 goto error_close_devices;
 936         }
 937
 938         bdev = fs_devices->latest_bdev;
 939         s = sget(fs_type, btrfs_test_super, btrfs_set_super,
 940                  fs_info->tree_root);
 941         if (IS_ERR(s)) {
 942                 error = PTR_ERR(s);
 943                 goto error_close_devices;
 944         }
 945
 946         if (s->s_root) {
 947                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 948                         deactivate_locked_super(s);
 949                         error = -EBUSY;
 950                         goto error_close_devices;
 951                 }
 952
 953                 btrfs_close_devices(fs_devices);
 954                 free_fs_info(fs_info);
 955         } else {
 956                 char b[BDEVNAME_SIZE];
 957
 958                 s->s_flags = flags | MS_NOSEC;
 959                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 960                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 961                 error = btrfs_fill_super(s, fs_devices, data,
 962                                          flags & MS_SILENT ? 1 : 0);
 963                 if (error) {
 964                         deactivate_locked_super(s);
 965                         return ERR_PTR(error);
 966                 }
 967
 968                 s->s_flags |= MS_ACTIVE;
 969         }
 970
 971         root = get_default_root(s, subvol_objectid);
 972         if (IS_ERR(root)) {
 973                 deactivate_locked_super(s);
 974                 return root;
 975         }
 976
 977         return root;
 978
 979 error_close_devices:
 980         btrfs_close_devices(fs_devices);
 981 error_fs_info:
 982         free_fs_info(fs_info);
 983         return ERR_PTR(error);
 984 }
 985
 986 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 987 {
 988         struct btrfs_root *root = btrfs_sb(sb);
 989         int ret;
 990
 991         ret = btrfs_parse_options(root, data);
 992         if (ret)
 993                 return -EINVAL;
 994
 995         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 996                 return 0;
 997
 998         if (*flags & MS_RDONLY) {
 999                 sb->s_flags |= MS_RDONLY;
1000
1001                 ret =  btrfs_commit_super(root);
1002                 WARN_ON(ret);
1003         } else {
1004                 if (root->fs_info->fs_devices->rw_devices == 0)
1005                         return -EACCES;
1006
1007                 if (btrfs_super_log_root(root->fs_info->super_copy) != 0)
1008                         return -EINVAL;
1009
1010                 ret = btrfs_cleanup_fs_roots(root->fs_info);
1011                 WARN_ON(ret);
1012
1013                 /* recover relocation */
1014                 ret = btrfs_recover_relocation(root);
1015                 WARN_ON(ret);
1016
1017                 sb->s_flags &= ~MS_RDONLY;
1018         }
1019
1020         return 0;
1021 }
1022
1023 /* Used to sort the devices by max_avail(descending sort) */
1024 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1025                                        const void *dev_info2)
1026 {
1027         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1028             ((struct btrfs_device_info *)dev_info2)->max_avail)
1029                 return -1;
1030         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1031                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1032                 return 1;
1033         else
1034         return 0;
1035 }
1036
1037 /*
1038  * sort the devices by max_avail, in which max free extent size of each device
1039  * is stored.(Descending Sort)
1040  */
1041 static inline void btrfs_descending_sort_devices(
1042                                         struct btrfs_device_info *devices,
1043                                         size_t nr_devices)
1044 {
1045         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1046              btrfs_cmp_device_free_bytes, NULL);
1047 }
1048
1049 /*
1050  * The helper to calc the free space on the devices that can be used to store
1051  * file data.
1052  */
1053 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1054 {
1055         struct btrfs_fs_info *fs_info = root->fs_info;
1056         struct btrfs_device_info *devices_info;
1057         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1058         struct btrfs_device *device;
1059         u64 skip_space;
1060         u64 type;
1061         u64 avail_space;
1062         u64 used_space;
1063         u64 min_stripe_size;
1064         int min_stripes = 1, num_stripes = 1;
1065         int i = 0, nr_devices;
1066         int ret;
1067
1068         nr_devices = fs_info->fs_devices->open_devices;
1069         BUG_ON(!nr_devices);
1070
1071         devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1072                                GFP_NOFS);
1073         if (!devices_info)
1074                 return -ENOMEM;
1075
1076         /* calc min stripe number for data space alloction */
1077         type = btrfs_get_alloc_profile(root, 1);
1078         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1079                 min_stripes = 2;
1080                 num_stripes = nr_devices;
1081         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1082                 min_stripes = 2;
1083                 num_stripes = 2;
1084         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1085                 min_stripes = 4;
1086                 num_stripes = 4;
1087         }
1088
1089         if (type & BTRFS_BLOCK_GROUP_DUP)
1090                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1091         else
1092                 min_stripe_size = BTRFS_STRIPE_LEN;
1093
1094         list_for_each_entry(device, &fs_devices->devices, dev_list) {
1095                 if (!device->in_fs_metadata || !device->bdev)
1096                         continue;
1097
1098                 avail_space = device->total_bytes - device->bytes_used;
1099
1100                 /* align with stripe_len */
1101                 do_div(avail_space, BTRFS_STRIPE_LEN);
1102                 avail_space *= BTRFS_STRIPE_LEN;
1103
1104                 /*
1105                  * In order to avoid overwritting the superblock on the drive,
1106                  * btrfs starts at an offset of at least 1MB when doing chunk
1107                  * allocation.
1108                  */
1109                 skip_space = 1024 * 1024;
1110
1111                 /* user can set the offset in fs_info->alloc_start. */
1112                 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1113                     device->total_bytes)
1114                         skip_space = max(fs_info->alloc_start, skip_space);
1115
1116                 /*
1117                  * btrfs can not use the free space in [0, skip_space - 1],
1118                  * we must subtract it from the total. In order to implement
1119                  * it, we account the used space in this range first.
1120                  */
1121                 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1122                                                      &used_space);
1123                 if (ret) {
1124                         kfree(devices_info);
1125                         return ret;
1126                 }
1127
1128                 /* calc the free space in [0, skip_space - 1] */
1129                 skip_space -= used_space;
1130
1131                 /*
1132                  * we can use the free space in [0, skip_space - 1], subtract
1133                  * it from the total.
1134                  */
1135                 if (avail_space && avail_space >= skip_space)
1136                         avail_space -= skip_space;
1137                 else
1138                         avail_space = 0;
1139
1140                 if (avail_space < min_stripe_size)
1141                         continue;
1142
1143                 devices_info[i].dev = device;
1144                 devices_info[i].max_avail = avail_space;
1145
1146                 i++;
1147         }
1148
1149         nr_devices = i;
1150
1151         btrfs_descending_sort_devices(devices_info, nr_devices);
1152
1153         i = nr_devices - 1;
1154         avail_space = 0;
1155         while (nr_devices >= min_stripes) {
1156                 if (num_stripes > nr_devices)
1157                         num_stripes = nr_devices;
1158
1159                 if (devices_info[i].max_avail >= min_stripe_size) {
1160                         int j;
1161                         u64 alloc_size;
1162
1163                         avail_space += devices_info[i].max_avail * num_stripes;
1164                         alloc_size = devices_info[i].max_avail;
1165                         for (j = i + 1 - num_stripes; j <= i; j++)
1166                                 devices_info[j].max_avail -= alloc_size;
1167                 }
1168                 i--;
1169                 nr_devices--;
1170         }
1171
1172         kfree(devices_info);
1173         *free_bytes = avail_space;
1174         return 0;
1175 }
1176
1177 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1178 {
1179         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
1180         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1181         struct list_head *head = &root->fs_info->space_info;
1182         struct btrfs_space_info *found;
1183         u64 total_used = 0;
1184         u64 total_free_data = 0;
1185         int bits = dentry->d_sb->s_blocksize_bits;
1186         __be32 *fsid = (__be32 *)root->fs_info->fsid;
1187         int ret;
1188
1189         /* holding chunk_muext to avoid allocating new chunks */
1190         mutex_lock(&root->fs_info->chunk_mutex);
1191         rcu_read_lock();
1192         list_for_each_entry_rcu(found, head, list) {
1193                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1194                         total_free_data += found->disk_total - found->disk_used;
1195                         total_free_data -=
1196                                 btrfs_account_ro_block_groups_free_space(found);
1197                 }
1198
1199                 total_used += found->disk_used;
1200         }
1201         rcu_read_unlock();
1202
1203         buf->f_namelen = BTRFS_NAME_LEN;
1204         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1205         buf->f_bfree = buf->f_blocks - (total_used >> bits);
1206         buf->f_bsize = dentry->d_sb->s_blocksize;
1207         buf->f_type = BTRFS_SUPER_MAGIC;
1208         buf->f_bavail = total_free_data;
1209         ret = btrfs_calc_avail_data_space(root, &total_free_data);
1210         if (ret) {
1211                 mutex_unlock(&root->fs_info->chunk_mutex);
1212                 return ret;
1213         }
1214         buf->f_bavail += total_free_data;
1215         buf->f_bavail = buf->f_bavail >> bits;
1216         mutex_unlock(&root->fs_info->chunk_mutex);
1217
1218         /* We treat it as constant endianness (it doesn't matter _which_)
1219            because we want the fsid to come out the same whether mounted
1220            on a big-endian or little-endian host */
1221         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1222         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1223         /* Mask in the root object ID too, to disambiguate subvols */
1224         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1225         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1226
1227         return 0;
1228 }
1229
1230 static struct file_system_type btrfs_fs_type = {
1231         .owner          = THIS_MODULE,
1232         .name           = "btrfs",
1233         .mount          = btrfs_mount,
1234         .kill_sb        = kill_anon_super,
1235         .fs_flags       = FS_REQUIRES_DEV,
1236 };
1237
1238 /*
1239  * used by btrfsctl to scan devices when no FS is mounted
1240  */
1241 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1242                                 unsigned long arg)
1243 {
1244         struct btrfs_ioctl_vol_args *vol;
1245         struct btrfs_fs_devices *fs_devices;
1246         int ret = -ENOTTY;
1247
1248         if (!capable(CAP_SYS_ADMIN))
1249                 return -EPERM;
1250
1251         vol = memdup_user((void __user *)arg, sizeof(*vol));
1252         if (IS_ERR(vol))
1253                 return PTR_ERR(vol);
1254
1255         switch (cmd) {
1256         case BTRFS_IOC_SCAN_DEV:
1257                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1258                                             &btrfs_fs_type, &fs_devices);
1259                 break;
1260         }
1261
1262         kfree(vol);
1263         return ret;
1264 }
1265
1266 static int btrfs_freeze(struct super_block *sb)
1267 {
1268         struct btrfs_root *root = btrfs_sb(sb);
1269         mutex_lock(&root->fs_info->transaction_kthread_mutex);
1270         mutex_lock(&root->fs_info->cleaner_mutex);
1271         return 0;
1272 }
1273
1274 static int btrfs_unfreeze(struct super_block *sb)
1275 {
1276         struct btrfs_root *root = btrfs_sb(sb);
1277         mutex_unlock(&root->fs_info->cleaner_mutex);
1278         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1279         return 0;
1280 }
1281
1282 static void btrfs_fs_dirty_inode(struct inode *inode, int flags)
1283 {
1284         int ret;
1285
1286         ret = btrfs_dirty_inode(inode);
1287         if (ret)
1288                 printk_ratelimited(KERN_ERR "btrfs: fail to dirty inode %Lu "
1289                                    "error %d\n", btrfs_ino(inode), ret);
1290 }
1291
1292 static const struct super_operations btrfs_super_ops = {
1293         .drop_inode     = btrfs_drop_inode,
1294         .evict_inode    = btrfs_evict_inode,
1295         .put_super      = btrfs_put_super,
1296         .sync_fs        = btrfs_sync_fs,
1297         .show_options   = btrfs_show_options,
1298         .write_inode    = btrfs_write_inode,
1299         .dirty_inode    = btrfs_fs_dirty_inode,
1300         .alloc_inode    = btrfs_alloc_inode,
1301         .destroy_inode  = btrfs_destroy_inode,
1302         .statfs         = btrfs_statfs,
1303         .remount_fs     = btrfs_remount,
1304         .freeze_fs      = btrfs_freeze,
1305         .unfreeze_fs    = btrfs_unfreeze,
1306 };
1307
1308 static const struct file_operations btrfs_ctl_fops = {
1309         .unlocked_ioctl  = btrfs_control_ioctl,
1310         .compat_ioctl = btrfs_control_ioctl,
1311         .owner   = THIS_MODULE,
1312         .llseek = noop_llseek,
1313 };
1314
1315 static struct miscdevice btrfs_misc = {
1316         .minor          = BTRFS_MINOR,
1317         .name           = "btrfs-control",
1318         .fops           = &btrfs_ctl_fops
1319 };
1320
1321 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1322 MODULE_ALIAS("devname:btrfs-control");
1323
1324 static int btrfs_interface_init(void)
1325 {
1326         return misc_register(&btrfs_misc);
1327 }
1328
1329 static void btrfs_interface_exit(void)
1330 {
1331         if (misc_deregister(&btrfs_misc) < 0)
1332                 printk(KERN_INFO "misc_deregister failed for control device");
1333 }
1334
1335 static int __init init_btrfs_fs(void)
1336 {
1337         int err;
1338
1339         err = btrfs_init_sysfs();
1340         if (err)
1341                 return err;
1342
1343         err = btrfs_init_compress();
1344         if (err)
1345                 goto free_sysfs;
1346
1347         err = btrfs_init_cachep();
1348         if (err)
1349                 goto free_compress;
1350
1351         err = extent_io_init();
1352         if (err)
1353                 goto free_cachep;
1354
1355         err = extent_map_init();
1356         if (err)
1357                 goto free_extent_io;
1358
1359         err = btrfs_delayed_inode_init();
1360         if (err)
1361                 goto free_extent_map;
1362
1363         err = btrfs_interface_init();
1364         if (err)
1365                 goto free_delayed_inode;
1366
1367         err = register_filesystem(&btrfs_fs_type);
1368         if (err)
1369                 goto unregister_ioctl;
1370
1371         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1372         return 0;
1373
1374 unregister_ioctl:
1375         btrfs_interface_exit();
1376 free_delayed_inode:
1377         btrfs_delayed_inode_exit();
1378 free_extent_map:
1379         extent_map_exit();
1380 free_extent_io:
1381         extent_io_exit();
1382 free_cachep:
1383         btrfs_destroy_cachep();
1384 free_compress:
1385         btrfs_exit_compress();
1386 free_sysfs:
1387         btrfs_exit_sysfs();
1388         return err;
1389 }
1390
1391 static void __exit exit_btrfs_fs(void)
1392 {
1393         btrfs_destroy_cachep();
1394         btrfs_delayed_inode_exit();
1395         extent_map_exit();
1396         extent_io_exit();
1397         btrfs_interface_exit();
1398         unregister_filesystem(&btrfs_fs_type);
1399         btrfs_exit_sysfs();
1400         btrfs_cleanup_fs_uuids();
1401         btrfs_exit_compress();
1402 }
1403
1404 module_init(init_btrfs_fs)
1405 module_exit(exit_btrfs_fs)
1406
1407 MODULE_LICENSE("GPL");