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/smp_lock.h>
  30 #include <linux/backing-dev.h>
  31 #include <linux/mount.h>
  32 #include <linux/mpage.h>
  33 #include <linux/swap.h>
  34 #include <linux/writeback.h>
  35 #include <linux/statfs.h>
  36 #include <linux/compat.h>
  37 #include <linux/parser.h>
  38 #include <linux/ctype.h>
  39 #include <linux/namei.h>
  40 #include <linux/miscdevice.h>
  41 #include <linux/magic.h>
  42 #include "compat.h"
  43 #include "ctree.h"
  44 #include "disk-io.h"
  45 #include "transaction.h"
  46 #include "btrfs_inode.h"
  47 #include "ioctl.h"
  48 #include "print-tree.h"
  49 #include "xattr.h"
  50 #include "volumes.h"
  51 #include "version.h"
  52 #include "export.h"
  53 #include "compression.h"
  54
  55 static struct super_operations btrfs_super_ops;
  56
  57 static void btrfs_put_super(struct super_block *sb)
  58 {
  59         struct btrfs_root *root = btrfs_sb(sb);
  60         int ret;
  61
  62         ret = close_ctree(root);
  63         sb->s_fs_info = NULL;
  64 }
  65
  66 enum {
  67         Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
  68         Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
  69         Opt_ssd, Opt_nossd, Opt_thread_pool, Opt_noacl,  Opt_compress,
  70         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_err,
  71 };
  72
  73 static match_table_t tokens = {
  74         {Opt_degraded, "degraded"},
  75         {Opt_subvol, "subvol=%s"},
  76         {Opt_device, "device=%s"},
  77         {Opt_nodatasum, "nodatasum"},
  78         {Opt_nodatacow, "nodatacow"},
  79         {Opt_nobarrier, "nobarrier"},
  80         {Opt_max_extent, "max_extent=%s"},
  81         {Opt_max_inline, "max_inline=%s"},
  82         {Opt_alloc_start, "alloc_start=%s"},
  83         {Opt_thread_pool, "thread_pool=%d"},
  84         {Opt_compress, "compress"},
  85         {Opt_ssd, "ssd"},
  86         {Opt_nossd, "nossd"},
  87         {Opt_noacl, "noacl"},
  88         {Opt_notreelog, "notreelog"},
  89         {Opt_flushoncommit, "flushoncommit"},
  90         {Opt_ratio, "metadata_ratio=%d"},
  91         {Opt_err, NULL},
  92 };
  93
  94 u64 btrfs_parse_size(char *str)
  95 {
  96         u64 res;
  97         int mult = 1;
  98         char *end;
  99         char last;
 100
 101         res = simple_strtoul(str, &end, 10);
 102
 103         last = end[0];
 104         if (isalpha(last)) {
 105                 last = tolower(last);
 106                 switch (last) {
 107                 case 'g':
 108                         mult *= 1024;
 109                 case 'm':
 110                         mult *= 1024;
 111                 case 'k':
 112                         mult *= 1024;
 113                 }
 114                 res = res * mult;
 115         }
 116         return res;
 117 }
 118
 119 /*
 120  * Regular mount options parser.  Everything that is needed only when
 121  * reading in a new superblock is parsed here.
 122  */
 123 int btrfs_parse_options(struct btrfs_root *root, char *options)
 124 {
 125         struct btrfs_fs_info *info = root->fs_info;
 126         substring_t args[MAX_OPT_ARGS];
 127         char *p, *num;
 128         int intarg;
 129
 130         if (!options)
 131                 return 0;
 132
 133         /*
 134          * strsep changes the string, duplicate it because parse_options
 135          * gets called twice
 136          */
 137         options = kstrdup(options, GFP_NOFS);
 138         if (!options)
 139                 return -ENOMEM;
 140
 141
 142         while ((p = strsep(&options, ",")) != NULL) {
 143                 int token;
 144                 if (!*p)
 145                         continue;
 146
 147                 token = match_token(p, tokens, args);
 148                 switch (token) {
 149                 case Opt_degraded:
 150                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 151                         btrfs_set_opt(info->mount_opt, DEGRADED);
 152                         break;
 153                 case Opt_subvol:
 154                 case Opt_device:
 155                         /*
 156                          * These are parsed by btrfs_parse_early_options
 157                          * and can be happily ignored here.
 158                          */
 159                         break;
 160                 case Opt_nodatasum:
 161                         printk(KERN_INFO "btrfs: setting nodatacsum\n");
 162                         btrfs_set_opt(info->mount_opt, NODATASUM);
 163                         break;
 164                 case Opt_nodatacow:
 165                         printk(KERN_INFO "btrfs: setting nodatacow\n");
 166                         btrfs_set_opt(info->mount_opt, NODATACOW);
 167                         btrfs_set_opt(info->mount_opt, NODATASUM);
 168                         break;
 169                 case Opt_compress:
 170                         printk(KERN_INFO "btrfs: use compression\n");
 171                         btrfs_set_opt(info->mount_opt, COMPRESS);
 172                         break;
 173                 case Opt_ssd:
 174                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 175                         btrfs_set_opt(info->mount_opt, SSD);
 176                         break;
 177                 case Opt_nossd:
 178                         printk(KERN_INFO "btrfs: not using ssd allocation scheme\n");
 179                         btrfs_clear_opt(info->mount_opt, SSD);
 180                         break;
 181                 case Opt_nobarrier:
 182                         printk(KERN_INFO "btrfs: turning off barriers\n");
 183                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 184                         break;
 185                 case Opt_thread_pool:
 186                         intarg = 0;
 187                         match_int(&args[0], &intarg);
 188                         if (intarg) {
 189                                 info->thread_pool_size = intarg;
 190                                 printk(KERN_INFO "btrfs: thread pool %d\n",
 191                                        info->thread_pool_size);
 192                         }
 193                         break;
 194                 case Opt_max_extent:
 195                         num = match_strdup(&args[0]);
 196                         if (num) {
 197                                 info->max_extent = btrfs_parse_size(num);
 198                                 kfree(num);
 199
 200                                 info->max_extent = max_t(u64,
 201                                         info->max_extent, root->sectorsize);
 202                                 printk(KERN_INFO "btrfs: max_extent at %llu\n",
 203                                        (unsigned long long)info->max_extent);
 204                         }
 205                         break;
 206                 case Opt_max_inline:
 207                         num = match_strdup(&args[0]);
 208                         if (num) {
 209                                 info->max_inline = btrfs_parse_size(num);
 210                                 kfree(num);
 211
 212                                 if (info->max_inline) {
 213                                         info->max_inline = max_t(u64,
 214                                                 info->max_inline,
 215                                                 root->sectorsize);
 216                                 }
 217                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 218                                         (unsigned long long)info->max_inline);
 219                         }
 220                         break;
 221                 case Opt_alloc_start:
 222                         num = match_strdup(&args[0]);
 223                         if (num) {
 224                                 info->alloc_start = btrfs_parse_size(num);
 225                                 kfree(num);
 226                                 printk(KERN_INFO
 227                                         "btrfs: allocations start at %llu\n",
 228                                         (unsigned long long)info->alloc_start);
 229                         }
 230                         break;
 231                 case Opt_noacl:
 232                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 233                         break;
 234                 case Opt_notreelog:
 235                         printk(KERN_INFO "btrfs: disabling tree log\n");
 236                         btrfs_set_opt(info->mount_opt, NOTREELOG);
 237                         break;
 238                 case Opt_flushoncommit:
 239                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
 240                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
 241                         break;
 242                 case Opt_ratio:
 243                         intarg = 0;
 244                         match_int(&args[0], &intarg);
 245                         if (intarg) {
 246                                 info->metadata_ratio = intarg;
 247                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
 248                                        info->metadata_ratio);
 249                         }
 250                         break;
 251                 default:
 252                         break;
 253                 }
 254         }
 255         kfree(options);
 256         return 0;
 257 }
 258
 259 /*
 260  * Parse mount options that are required early in the mount process.
 261  *
 262  * All other options will be parsed on much later in the mount process and
 263  * only when we need to allocate a new super block.
 264  */
 265 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 266                 void *holder, char **subvol_name,
 267                 struct btrfs_fs_devices **fs_devices)
 268 {
 269         substring_t args[MAX_OPT_ARGS];
 270         char *opts, *p;
 271         int error = 0;
 272
 273         if (!options)
 274                 goto out;
 275
 276         /*
 277          * strsep changes the string, duplicate it because parse_options
 278          * gets called twice
 279          */
 280         opts = kstrdup(options, GFP_KERNEL);
 281         if (!opts)
 282                 return -ENOMEM;
 283
 284         while ((p = strsep(&opts, ",")) != NULL) {
 285                 int token;
 286                 if (!*p)
 287                         continue;
 288
 289                 token = match_token(p, tokens, args);
 290                 switch (token) {
 291                 case Opt_subvol:
 292                         *subvol_name = match_strdup(&args[0]);
 293                         break;
 294                 case Opt_device:
 295                         error = btrfs_scan_one_device(match_strdup(&args[0]),
 296                                         flags, holder, fs_devices);
 297                         if (error)
 298                                 goto out_free_opts;
 299                         break;
 300                 default:
 301                         break;
 302                 }
 303         }
 304
 305  out_free_opts:
 306         kfree(opts);
 307  out:
 308         /*
 309          * If no subvolume name is specified we use the default one.  Allocate
 310          * a copy of the string "." here so that code later in the
 311          * mount path doesn't care if it's the default volume or another one.
 312          */
 313         if (!*subvol_name) {
 314                 *subvol_name = kstrdup(".", GFP_KERNEL);
 315                 if (!*subvol_name)
 316                         return -ENOMEM;
 317         }
 318         return error;
 319 }
 320
 321 static int btrfs_fill_super(struct super_block *sb,
 322                             struct btrfs_fs_devices *fs_devices,
 323                             void *data, int silent)
 324 {
 325         struct inode *inode;
 326         struct dentry *root_dentry;
 327         struct btrfs_super_block *disk_super;
 328         struct btrfs_root *tree_root;
 329         struct btrfs_key key;
 330         int err;
 331
 332         sb->s_maxbytes = MAX_LFS_FILESIZE;
 333         sb->s_magic = BTRFS_SUPER_MAGIC;
 334         sb->s_op = &btrfs_super_ops;
 335         sb->s_export_op = &btrfs_export_ops;
 336         sb->s_xattr = btrfs_xattr_handlers;
 337         sb->s_time_gran = 1;
 338         sb->s_flags |= MS_POSIXACL;
 339
 340         tree_root = open_ctree(sb, fs_devices, (char *)data);
 341
 342         if (IS_ERR(tree_root)) {
 343                 printk("btrfs: open_ctree failed\n");
 344                 return PTR_ERR(tree_root);
 345         }
 346         sb->s_fs_info = tree_root;
 347         disk_super = &tree_root->fs_info->super_copy;
 348
 349         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 350         key.type = BTRFS_INODE_ITEM_KEY;
 351         key.offset = 0;
 352         inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root);
 353         if (IS_ERR(inode)) {
 354                 err = PTR_ERR(inode);
 355                 goto fail_close;
 356         }
 357
 358         root_dentry = d_alloc_root(inode);
 359         if (!root_dentry) {
 360                 iput(inode);
 361                 err = -ENOMEM;
 362                 goto fail_close;
 363         }
 364 #if 0
 365         /* this does the super kobj at the same time */
 366         err = btrfs_sysfs_add_super(tree_root->fs_info);
 367         if (err)
 368                 goto fail_close;
 369 #endif
 370
 371         sb->s_root = root_dentry;
 372
 373         save_mount_options(sb, data);
 374         return 0;
 375
 376 fail_close:
 377         close_ctree(tree_root);
 378         return err;
 379 }
 380
 381 int btrfs_sync_fs(struct super_block *sb, int wait)
 382 {
 383         struct btrfs_trans_handle *trans;
 384         struct btrfs_root *root = btrfs_sb(sb);
 385         int ret;
 386
 387         if (sb->s_flags & MS_RDONLY)
 388                 return 0;
 389
 390         sb->s_dirt = 0;
 391         if (!wait) {
 392                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 393                 return 0;
 394         }
 395
 396         btrfs_start_delalloc_inodes(root);
 397         btrfs_wait_ordered_extents(root, 0);
 398
 399         trans = btrfs_start_transaction(root, 1);
 400         ret = btrfs_commit_transaction(trans, root);
 401         sb->s_dirt = 0;
 402         return ret;
 403 }
 404
 405 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 406 {
 407         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
 408         struct btrfs_fs_info *info = root->fs_info;
 409
 410         if (btrfs_test_opt(root, DEGRADED))
 411                 seq_puts(seq, ",degraded");
 412         if (btrfs_test_opt(root, NODATASUM))
 413                 seq_puts(seq, ",nodatasum");
 414         if (btrfs_test_opt(root, NODATACOW))
 415                 seq_puts(seq, ",nodatacow");
 416         if (btrfs_test_opt(root, NOBARRIER))
 417                 seq_puts(seq, ",nobarrier");
 418         if (info->max_extent != (u64)-1)
 419                 seq_printf(seq, ",max_extent=%llu",
 420                            (unsigned long long)info->max_extent);
 421         if (info->max_inline != 8192 * 1024)
 422                 seq_printf(seq, ",max_inline=%llu",
 423                            (unsigned long long)info->max_inline);
 424         if (info->alloc_start != 0)
 425                 seq_printf(seq, ",alloc_start=%llu",
 426                            (unsigned long long)info->alloc_start);
 427         if (info->thread_pool_size !=  min_t(unsigned long,
 428                                              num_online_cpus() + 2, 8))
 429                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 430         if (btrfs_test_opt(root, COMPRESS))
 431                 seq_puts(seq, ",compress");
 432         if (btrfs_test_opt(root, SSD))
 433                 seq_puts(seq, ",ssd");
 434         if (btrfs_test_opt(root, NOTREELOG))
 435                 seq_puts(seq, ",notreelog");
 436         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 437                 seq_puts(seq, ",flushoncommit");
 438         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 439                 seq_puts(seq, ",noacl");
 440         return 0;
 441 }
 442
 443 static void btrfs_write_super(struct super_block *sb)
 444 {
 445         sb->s_dirt = 0;
 446 }
 447
 448 static int btrfs_test_super(struct super_block *s, void *data)
 449 {
 450         struct btrfs_fs_devices *test_fs_devices = data;
 451         struct btrfs_root *root = btrfs_sb(s);
 452
 453         return root->fs_info->fs_devices == test_fs_devices;
 454 }
 455
 456 /*
 457  * Find a superblock for the given device / mount point.
 458  *
 459  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 460  *        for multiple device setup.  Make sure to keep it in sync.
 461  */
 462 static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 463                 const char *dev_name, void *data, struct vfsmount *mnt)
 464 {
 465         char *subvol_name = NULL;
 466         struct block_device *bdev = NULL;
 467         struct super_block *s;
 468         struct dentry *root;
 469         struct btrfs_fs_devices *fs_devices = NULL;
 470         fmode_t mode = FMODE_READ;
 471         int error = 0;
 472
 473         if (!(flags & MS_RDONLY))
 474                 mode |= FMODE_WRITE;
 475
 476         error = btrfs_parse_early_options(data, mode, fs_type,
 477                                           &subvol_name, &fs_devices);
 478         if (error)
 479                 return error;
 480
 481         error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
 482         if (error)
 483                 goto error_free_subvol_name;
 484
 485         error = btrfs_open_devices(fs_devices, mode, fs_type);
 486         if (error)
 487                 goto error_free_subvol_name;
 488
 489         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 490                 error = -EACCES;
 491                 goto error_close_devices;
 492         }
 493
 494         bdev = fs_devices->latest_bdev;
 495         s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
 496         if (IS_ERR(s))
 497                 goto error_s;
 498
 499         if (s->s_root) {
 500                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 501                         deactivate_locked_super(s);
 502                         error = -EBUSY;
 503                         goto error_close_devices;
 504                 }
 505
 506                 btrfs_close_devices(fs_devices);
 507         } else {
 508                 char b[BDEVNAME_SIZE];
 509
 510                 s->s_flags = flags;
 511                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 512                 error = btrfs_fill_super(s, fs_devices, data,
 513                                          flags & MS_SILENT ? 1 : 0);
 514                 if (error) {
 515                         deactivate_locked_super(s);
 516                         goto error_free_subvol_name;
 517                 }
 518
 519                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 520                 s->s_flags |= MS_ACTIVE;
 521         }
 522
 523         if (!strcmp(subvol_name, "."))
 524                 root = dget(s->s_root);
 525         else {
 526                 mutex_lock(&s->s_root->d_inode->i_mutex);
 527                 root = lookup_one_len(subvol_name, s->s_root,
 528                                       strlen(subvol_name));
 529                 mutex_unlock(&s->s_root->d_inode->i_mutex);
 530
 531                 if (IS_ERR(root)) {
 532                         deactivate_locked_super(s);
 533                         error = PTR_ERR(root);
 534                         goto error_free_subvol_name;
 535                 }
 536                 if (!root->d_inode) {
 537                         dput(root);
 538                         deactivate_locked_super(s);
 539                         error = -ENXIO;
 540                         goto error_free_subvol_name;
 541                 }
 542         }
 543
 544         mnt->mnt_sb = s;
 545         mnt->mnt_root = root;
 546
 547         kfree(subvol_name);
 548         return 0;
 549
 550 error_s:
 551         error = PTR_ERR(s);
 552 error_close_devices:
 553         btrfs_close_devices(fs_devices);
 554 error_free_subvol_name:
 555         kfree(subvol_name);
 556         return error;
 557 }
 558
 559 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 560 {
 561         struct btrfs_root *root = btrfs_sb(sb);
 562         int ret;
 563
 564         ret = btrfs_parse_options(root, data);
 565         if (ret)
 566                 return -EINVAL;
 567
 568         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 569                 return 0;
 570
 571         if (*flags & MS_RDONLY) {
 572                 sb->s_flags |= MS_RDONLY;
 573
 574                 ret =  btrfs_commit_super(root);
 575                 WARN_ON(ret);
 576         } else {
 577                 if (root->fs_info->fs_devices->rw_devices == 0)
 578                         return -EACCES;
 579
 580                 if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
 581                         return -EINVAL;
 582
 583                 /* recover relocation */
 584                 ret = btrfs_recover_relocation(root);
 585                 WARN_ON(ret);
 586
 587                 ret = btrfs_cleanup_fs_roots(root->fs_info);
 588                 WARN_ON(ret);
 589
 590                 sb->s_flags &= ~MS_RDONLY;
 591         }
 592
 593         return 0;
 594 }
 595
 596 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 597 {
 598         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
 599         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
 600         int bits = dentry->d_sb->s_blocksize_bits;
 601         __be32 *fsid = (__be32 *)root->fs_info->fsid;
 602
 603         buf->f_namelen = BTRFS_NAME_LEN;
 604         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
 605         buf->f_bfree = buf->f_blocks -
 606                 (btrfs_super_bytes_used(disk_super) >> bits);
 607         buf->f_bavail = buf->f_bfree;
 608         buf->f_bsize = dentry->d_sb->s_blocksize;
 609         buf->f_type = BTRFS_SUPER_MAGIC;
 610
 611         /* We treat it as constant endianness (it doesn't matter _which_)
 612            because we want the fsid to come out the same whether mounted
 613            on a big-endian or little-endian host */
 614         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
 615         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
 616         /* Mask in the root object ID too, to disambiguate subvols */
 617         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
 618         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
 619
 620         return 0;
 621 }
 622
 623 static struct file_system_type btrfs_fs_type = {
 624         .owner          = THIS_MODULE,
 625         .name           = "btrfs",
 626         .get_sb         = btrfs_get_sb,
 627         .kill_sb        = kill_anon_super,
 628         .fs_flags       = FS_REQUIRES_DEV,
 629 };
 630
 631 /*
 632  * used by btrfsctl to scan devices when no FS is mounted
 633  */
 634 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 635                                 unsigned long arg)
 636 {
 637         struct btrfs_ioctl_vol_args *vol;
 638         struct btrfs_fs_devices *fs_devices;
 639         int ret = -ENOTTY;
 640
 641         if (!capable(CAP_SYS_ADMIN))
 642                 return -EPERM;
 643
 644         vol = memdup_user((void __user *)arg, sizeof(*vol));
 645         if (IS_ERR(vol))
 646                 return PTR_ERR(vol);
 647
 648         switch (cmd) {
 649         case BTRFS_IOC_SCAN_DEV:
 650                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
 651                                             &btrfs_fs_type, &fs_devices);
 652                 break;
 653         }
 654
 655         kfree(vol);
 656         return ret;
 657 }
 658
 659 static int btrfs_freeze(struct super_block *sb)
 660 {
 661         struct btrfs_root *root = btrfs_sb(sb);
 662         mutex_lock(&root->fs_info->transaction_kthread_mutex);
 663         mutex_lock(&root->fs_info->cleaner_mutex);
 664         return 0;
 665 }
 666
 667 static int btrfs_unfreeze(struct super_block *sb)
 668 {
 669         struct btrfs_root *root = btrfs_sb(sb);
 670         mutex_unlock(&root->fs_info->cleaner_mutex);
 671         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
 672         return 0;
 673 }
 674
 675 static struct super_operations btrfs_super_ops = {
 676         .delete_inode   = btrfs_delete_inode,
 677         .put_super      = btrfs_put_super,
 678         .write_super    = btrfs_write_super,
 679         .sync_fs        = btrfs_sync_fs,
 680         .show_options   = btrfs_show_options,
 681         .write_inode    = btrfs_write_inode,
 682         .dirty_inode    = btrfs_dirty_inode,
 683         .alloc_inode    = btrfs_alloc_inode,
 684         .destroy_inode  = btrfs_destroy_inode,
 685         .statfs         = btrfs_statfs,
 686         .remount_fs     = btrfs_remount,
 687         .freeze_fs      = btrfs_freeze,
 688         .unfreeze_fs    = btrfs_unfreeze,
 689 };
 690
 691 static const struct file_operations btrfs_ctl_fops = {
 692         .unlocked_ioctl  = btrfs_control_ioctl,
 693         .compat_ioctl = btrfs_control_ioctl,
 694         .owner   = THIS_MODULE,
 695 };
 696
 697 static struct miscdevice btrfs_misc = {
 698         .minor          = MISC_DYNAMIC_MINOR,
 699         .name           = "btrfs-control",
 700         .fops           = &btrfs_ctl_fops
 701 };
 702
 703 static int btrfs_interface_init(void)
 704 {
 705         return misc_register(&btrfs_misc);
 706 }
 707
 708 static void btrfs_interface_exit(void)
 709 {
 710         if (misc_deregister(&btrfs_misc) < 0)
 711                 printk(KERN_INFO "misc_deregister failed for control device");
 712 }
 713
 714 static int __init init_btrfs_fs(void)
 715 {
 716         int err;
 717
 718         err = btrfs_init_sysfs();
 719         if (err)
 720                 return err;
 721
 722         err = btrfs_init_cachep();
 723         if (err)
 724                 goto free_sysfs;
 725
 726         err = extent_io_init();
 727         if (err)
 728                 goto free_cachep;
 729
 730         err = extent_map_init();
 731         if (err)
 732                 goto free_extent_io;
 733
 734         err = btrfs_interface_init();
 735         if (err)
 736                 goto free_extent_map;
 737
 738         err = register_filesystem(&btrfs_fs_type);
 739         if (err)
 740                 goto unregister_ioctl;
 741
 742         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
 743         return 0;
 744
 745 unregister_ioctl:
 746         btrfs_interface_exit();
 747 free_extent_map:
 748         extent_map_exit();
 749 free_extent_io:
 750         extent_io_exit();
 751 free_cachep:
 752         btrfs_destroy_cachep();
 753 free_sysfs:
 754         btrfs_exit_sysfs();
 755         return err;
 756 }
 757
 758 static void __exit exit_btrfs_fs(void)
 759 {
 760         btrfs_destroy_cachep();
 761         extent_map_exit();
 762         extent_io_exit();
 763         btrfs_interface_exit();
 764         unregister_filesystem(&btrfs_fs_type);
 765         btrfs_exit_sysfs();
 766         btrfs_cleanup_fs_uuids();
 767         btrfs_zlib_exit();
 768 }
 769
 770 module_init(init_btrfs_fs)
 771 module_exit(exit_btrfs_fs)
 772
 773 MODULE_LICENSE("GPL");