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 "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 55static const struct super_operations btrfs_super_ops; 56 57static 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 66enum { 67 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum, 68 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, 69 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress, 70 Opt_compress_force, Opt_notreelog, Opt_ratio, Opt_flushoncommit, 71 Opt_discard, Opt_err, 72}; 73 74static match_table_t tokens = { 75 {Opt_degraded, "degraded"}, 76 {Opt_subvol, "subvol=%s"}, 77 {Opt_subvolid, "subvolid=%d"}, 78 {Opt_device, "device=%s"}, 79 {Opt_nodatasum, "nodatasum"}, 80 {Opt_nodatacow, "nodatacow"}, 81 {Opt_nobarrier, "nobarrier"}, 82 {Opt_max_inline, "max_inline=%s"}, 83 {Opt_alloc_start, "alloc_start=%s"}, 84 {Opt_thread_pool, "thread_pool=%d"}, 85 {Opt_compress, "compress"}, 86 {Opt_compress_force, "compress-force"}, 87 {Opt_ssd, "ssd"}, 88 {Opt_ssd_spread, "ssd_spread"}, 89 {Opt_nossd, "nossd"}, 90 {Opt_noacl, "noacl"}, 91 {Opt_notreelog, "notreelog"}, 92 {Opt_flushoncommit, "flushoncommit"}, 93 {Opt_ratio, "metadata_ratio=%d"}, 94 {Opt_discard, "discard"}, 95 {Opt_err, NULL}, 96}; 97 98/* 99 * Regular mount options parser. Everything that is needed only when 100 * reading in a new superblock is parsed here. 101 */ 102int btrfs_parse_options(struct btrfs_root *root, char *options) 103{ 104 struct btrfs_fs_info *info = root->fs_info; 105 substring_t args[MAX_OPT_ARGS]; 106 char *p, *num, *orig; 107 int intarg; 108 int ret = 0; 109 110 if (!options) 111 return 0; 112 113 /* 114 * strsep changes the string, duplicate it because parse_options 115 * gets called twice 116 */ 117 options = kstrdup(options, GFP_NOFS); 118 if (!options) 119 return -ENOMEM; 120 121 orig = options; 122 123 while ((p = strsep(&options, ",")) != NULL) { 124 int token; 125 if (!*p) 126 continue; 127 128 token = match_token(p, tokens, args); 129 switch (token) { 130 case Opt_degraded: 131 printk(KERN_INFO "btrfs: allowing degraded mounts\n"); 132 btrfs_set_opt(info->mount_opt, DEGRADED); 133 break; 134 case Opt_subvol: 135 case Opt_subvolid: 136 case Opt_device: 137 /* 138 * These are parsed by btrfs_parse_early_options 139 * and can be happily ignored here. 140 */ 141 break; 142 case Opt_nodatasum: 143 printk(KERN_INFO "btrfs: setting nodatasum\n"); 144 btrfs_set_opt(info->mount_opt, NODATASUM); 145 break; 146 case Opt_nodatacow: 147 printk(KERN_INFO "btrfs: setting nodatacow\n"); 148 btrfs_set_opt(info->mount_opt, NODATACOW); 149 btrfs_set_opt(info->mount_opt, NODATASUM); 150 break; 151 case Opt_compress: 152 printk(KERN_INFO "btrfs: use compression\n"); 153 btrfs_set_opt(info->mount_opt, COMPRESS); 154 break; 155 case Opt_compress_force: 156 printk(KERN_INFO "btrfs: forcing compression\n"); 157 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS); 158 btrfs_set_opt(info->mount_opt, COMPRESS); 159 break; 160 case Opt_ssd: 161 printk(KERN_INFO "btrfs: use ssd allocation scheme\n"); 162 btrfs_set_opt(info->mount_opt, SSD); 163 break; 164 case Opt_ssd_spread: 165 printk(KERN_INFO "btrfs: use spread ssd " 166 "allocation scheme\n"); 167 btrfs_set_opt(info->mount_opt, SSD); 168 btrfs_set_opt(info->mount_opt, SSD_SPREAD); 169 break; 170 case Opt_nossd: 171 printk(KERN_INFO "btrfs: not using ssd allocation " 172 "scheme\n"); 173 btrfs_set_opt(info->mount_opt, NOSSD); 174 btrfs_clear_opt(info->mount_opt, SSD); 175 btrfs_clear_opt(info->mount_opt, SSD_SPREAD); 176 break; 177 case Opt_nobarrier: 178 printk(KERN_INFO "btrfs: turning off barriers\n"); 179 btrfs_set_opt(info->mount_opt, NOBARRIER); 180 break; 181 case Opt_thread_pool: 182 intarg = 0; 183 match_int(&args[0], &intarg); 184 if (intarg) { 185 info->thread_pool_size = intarg; 186 printk(KERN_INFO "btrfs: thread pool %d\n", 187 info->thread_pool_size); 188 } 189 break; 190 case Opt_max_inline: 191 num = match_strdup(&args[0]); 192 if (num) { 193 info->max_inline = memparse(num, NULL); 194 kfree(num); 195 196 if (info->max_inline) { 197 info->max_inline = max_t(u64, 198 info->max_inline, 199 root->sectorsize); 200 } 201 printk(KERN_INFO "btrfs: max_inline at %llu\n", 202 (unsigned long long)info->max_inline); 203 } 204 break; 205 case Opt_alloc_start: 206 num = match_strdup(&args[0]); 207 if (num) { 208 info->alloc_start = memparse(num, NULL); 209 kfree(num); 210 printk(KERN_INFO 211 "btrfs: allocations start at %llu\n", 212 (unsigned long long)info->alloc_start); 213 } 214 break; 215 case Opt_noacl: 216 root->fs_info->sb->s_flags &= ~MS_POSIXACL; 217 break; 218 case Opt_notreelog: 219 printk(KERN_INFO "btrfs: disabling tree log\n"); 220 btrfs_set_opt(info->mount_opt, NOTREELOG); 221 break; 222 case Opt_flushoncommit: 223 printk(KERN_INFO "btrfs: turning on flush-on-commit\n"); 224 btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT); 225 break; 226 case Opt_ratio: 227 intarg = 0; 228 match_int(&args[0], &intarg); 229 if (intarg) { 230 info->metadata_ratio = intarg; 231 printk(KERN_INFO "btrfs: metadata ratio %d\n", 232 info->metadata_ratio); 233 } 234 break; 235 case Opt_discard: 236 btrfs_set_opt(info->mount_opt, DISCARD); 237 break; 238 case Opt_err: 239 printk(KERN_INFO "btrfs: unrecognized mount option " 240 "'%s'\n", p); 241 ret = -EINVAL; 242 goto out; 243 default: 244 break; 245 } 246 } 247out: 248 kfree(orig); 249 return ret; 250} 251 252/* 253 * Parse mount options that are required early in the mount process. 254 * 255 * All other options will be parsed on much later in the mount process and 256 * only when we need to allocate a new super block. 257 */ 258static int btrfs_parse_early_options(const char *options, fmode_t flags, 259 void *holder, char **subvol_name, u64 *subvol_objectid, 260 struct btrfs_fs_devices **fs_devices) 261{ 262 substring_t args[MAX_OPT_ARGS]; 263 char *opts, *p; 264 int error = 0; 265 int intarg; 266 267 if (!options) 268 goto out; 269 270 /* 271 * strsep changes the string, duplicate it because parse_options 272 * gets called twice 273 */ 274 opts = kstrdup(options, GFP_KERNEL); 275 if (!opts) 276 return -ENOMEM; 277 278 while ((p = strsep(&opts, ",")) != NULL) { 279 int token; 280 if (!*p) 281 continue; 282 283 token = match_token(p, tokens, args); 284 switch (token) { 285 case Opt_subvol: 286 *subvol_name = match_strdup(&args[0]); 287 break; 288 case Opt_subvolid: 289 intarg = 0; 290 error = match_int(&args[0], &intarg); 291 if (!error) { 292 /* we want the original fs_tree */ 293 if (!intarg) 294 *subvol_objectid = 295 BTRFS_FS_TREE_OBJECTID; 296 else 297 *subvol_objectid = intarg; 298 } 299 break; 300 case Opt_device: 301 error = btrfs_scan_one_device(match_strdup(&args[0]), 302 flags, holder, fs_devices); 303 if (error) 304 goto out_free_opts; 305 break; 306 default: 307 break; 308 } 309 } 310 311 out_free_opts: 312 kfree(opts); 313 out: 314 /* 315 * If no subvolume name is specified we use the default one. Allocate 316 * a copy of the string "." here so that code later in the 317 * mount path doesn't care if it's the default volume or another one. 318 */ 319 if (!*subvol_name) { 320 *subvol_name = kstrdup(".", GFP_KERNEL); 321 if (!*subvol_name) 322 return -ENOMEM; 323 } 324 return error; 325} 326 327static struct dentry *get_default_root(struct super_block *sb, 328 u64 subvol_objectid) 329{ 330 struct btrfs_root *root = sb->s_fs_info; 331 struct btrfs_root *new_root; 332 struct btrfs_dir_item *di; 333 struct btrfs_path *path; 334 struct btrfs_key location; 335 struct inode *inode; 336 struct dentry *dentry; 337 u64 dir_id; 338 int new = 0; 339 340 /* 341 * We have a specific subvol we want to mount, just setup location and 342 * go look up the root. 343 */ 344 if (subvol_objectid) { 345 location.objectid = subvol_objectid; 346 location.type = BTRFS_ROOT_ITEM_KEY; 347 location.offset = (u64)-1; 348 goto find_root; 349 } 350 351 path = btrfs_alloc_path(); 352 if (!path) 353 return ERR_PTR(-ENOMEM); 354 path->leave_spinning = 1; 355 356 /* 357 * Find the "default" dir item which points to the root item that we 358 * will mount by default if we haven't been given a specific subvolume 359 * to mount. 360 */ 361 dir_id = btrfs_super_root_dir(&root->fs_info->super_copy); 362 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0); 363 if (IS_ERR(di)) 364 return ERR_CAST(di); 365 if (!di) { 366 /* 367 * Ok the default dir item isn't there. This is weird since 368 * it's always been there, but don't freak out, just try and 369 * mount to root most subvolume. 370 */ 371 btrfs_free_path(path); 372 dir_id = BTRFS_FIRST_FREE_OBJECTID; 373 new_root = root->fs_info->fs_root; 374 goto setup_root; 375 } 376 377 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); 378 btrfs_free_path(path); 379 380find_root: 381 new_root = btrfs_read_fs_root_no_name(root->fs_info, &location); 382 if (IS_ERR(new_root)) 383 return ERR_PTR(PTR_ERR(new_root)); 384 385 if (btrfs_root_refs(&new_root->root_item) == 0) 386 return ERR_PTR(-ENOENT); 387 388 dir_id = btrfs_root_dirid(&new_root->root_item); 389setup_root: 390 location.objectid = dir_id; 391 location.type = BTRFS_INODE_ITEM_KEY; 392 location.offset = 0; 393 394 inode = btrfs_iget(sb, &location, new_root, &new); 395 if (IS_ERR(inode)) 396 return ERR_CAST(inode); 397 398 /* 399 * If we're just mounting the root most subvol put the inode and return 400 * a reference to the dentry. We will have already gotten a reference 401 * to the inode in btrfs_fill_super so we're good to go. 402 */ 403 if (!new && sb->s_root->d_inode == inode) { 404 iput(inode); 405 return dget(sb->s_root); 406 } 407 408 if (new) { 409 const struct qstr name = { .name = "/", .len = 1 }; 410 411 /* 412 * New inode, we need to make the dentry a sibling of s_root so 413 * everything gets cleaned up properly on unmount. 414 */ 415 dentry = d_alloc(sb->s_root, &name); 416 if (!dentry) { 417 iput(inode); 418 return ERR_PTR(-ENOMEM); 419 } 420 d_splice_alias(inode, dentry); 421 } else { 422 /* 423 * We found the inode in cache, just find a dentry for it and 424 * put the reference to the inode we just got. 425 */ 426 dentry = d_find_alias(inode); 427 iput(inode); 428 } 429 430 return dentry; 431} 432 433static int btrfs_fill_super(struct super_block *sb, 434 struct btrfs_fs_devices *fs_devices, 435 void *data, int silent) 436{ 437 struct inode *inode; 438 struct dentry *root_dentry; 439 struct btrfs_super_block *disk_super; 440 struct btrfs_root *tree_root; 441 struct btrfs_key key; 442 int err; 443 444 sb->s_maxbytes = MAX_LFS_FILESIZE; 445 sb->s_magic = BTRFS_SUPER_MAGIC; 446 sb->s_op = &btrfs_super_ops; 447 sb->s_export_op = &btrfs_export_ops; 448 sb->s_xattr = btrfs_xattr_handlers; 449 sb->s_time_gran = 1; 450#ifdef CONFIG_BTRFS_FS_POSIX_ACL 451 sb->s_flags |= MS_POSIXACL; 452#endif 453 454 tree_root = open_ctree(sb, fs_devices, (char *)data); 455 456 if (IS_ERR(tree_root)) { 457 printk("btrfs: open_ctree failed\n"); 458 return PTR_ERR(tree_root); 459 } 460 sb->s_fs_info = tree_root; 461 disk_super = &tree_root->fs_info->super_copy; 462 463 key.objectid = BTRFS_FIRST_FREE_OBJECTID; 464 key.type = BTRFS_INODE_ITEM_KEY; 465 key.offset = 0; 466 inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL); 467 if (IS_ERR(inode)) { 468 err = PTR_ERR(inode); 469 goto fail_close; 470 } 471 472 root_dentry = d_alloc_root(inode); 473 if (!root_dentry) { 474 iput(inode); 475 err = -ENOMEM; 476 goto fail_close; 477 } 478 479 sb->s_root = root_dentry; 480 481 save_mount_options(sb, data); 482 return 0; 483 484fail_close: 485 close_ctree(tree_root); 486 return err; 487} 488 489int btrfs_sync_fs(struct super_block *sb, int wait) 490{ 491 struct btrfs_trans_handle *trans; 492 struct btrfs_root *root = btrfs_sb(sb); 493 int ret; 494 495 if (!wait) { 496 filemap_flush(root->fs_info->btree_inode->i_mapping); 497 return 0; 498 } 499 500 btrfs_start_delalloc_inodes(root, 0); 501 btrfs_wait_ordered_extents(root, 0, 0); 502 503 trans = btrfs_start_transaction(root, 0); 504 ret = btrfs_commit_transaction(trans, root); 505 return ret; 506} 507 508static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs) 509{ 510 struct btrfs_root *root = btrfs_sb(vfs->mnt_sb); 511 struct btrfs_fs_info *info = root->fs_info; 512 513 if (btrfs_test_opt(root, DEGRADED)) 514 seq_puts(seq, ",degraded"); 515 if (btrfs_test_opt(root, NODATASUM)) 516 seq_puts(seq, ",nodatasum"); 517 if (btrfs_test_opt(root, NODATACOW)) 518 seq_puts(seq, ",nodatacow"); 519 if (btrfs_test_opt(root, NOBARRIER)) 520 seq_puts(seq, ",nobarrier"); 521 if (info->max_inline != 8192 * 1024) 522 seq_printf(seq, ",max_inline=%llu", 523 (unsigned long long)info->max_inline); 524 if (info->alloc_start != 0) 525 seq_printf(seq, ",alloc_start=%llu", 526 (unsigned long long)info->alloc_start); 527 if (info->thread_pool_size != min_t(unsigned long, 528 num_online_cpus() + 2, 8)) 529 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size); 530 if (btrfs_test_opt(root, COMPRESS)) 531 seq_puts(seq, ",compress"); 532 if (btrfs_test_opt(root, NOSSD)) 533 seq_puts(seq, ",nossd"); 534 if (btrfs_test_opt(root, SSD_SPREAD)) 535 seq_puts(seq, ",ssd_spread"); 536 else if (btrfs_test_opt(root, SSD)) 537 seq_puts(seq, ",ssd"); 538 if (btrfs_test_opt(root, NOTREELOG)) 539 seq_puts(seq, ",notreelog"); 540 if (btrfs_test_opt(root, FLUSHONCOMMIT)) 541 seq_puts(seq, ",flushoncommit"); 542 if (btrfs_test_opt(root, DISCARD)) 543 seq_puts(seq, ",discard"); 544 if (!(root->fs_info->sb->s_flags & MS_POSIXACL)) 545 seq_puts(seq, ",noacl"); 546 return 0; 547} 548 549static int btrfs_test_super(struct super_block *s, void *data) 550{ 551 struct btrfs_fs_devices *test_fs_devices = data; 552 struct btrfs_root *root = btrfs_sb(s); 553 554 return root->fs_info->fs_devices == test_fs_devices; 555} 556 557/* 558 * Find a superblock for the given device / mount point. 559 * 560 * Note: This is based on get_sb_bdev from fs/super.c with a few additions 561 * for multiple device setup. Make sure to keep it in sync. 562 */ 563static int btrfs_get_sb(struct file_system_type *fs_type, int flags, 564 const char *dev_name, void *data, struct vfsmount *mnt) 565{ 566 struct block_device *bdev = NULL; 567 struct super_block *s; 568 struct dentry *root; 569 struct btrfs_fs_devices *fs_devices = NULL; 570 fmode_t mode = FMODE_READ; 571 char *subvol_name = NULL; 572 u64 subvol_objectid = 0; 573 int error = 0; 574 int found = 0; 575 576 if (!(flags & MS_RDONLY)) 577 mode |= FMODE_WRITE; 578 579 error = btrfs_parse_early_options(data, mode, fs_type, 580 &subvol_name, &subvol_objectid, 581 &fs_devices); 582 if (error) 583 return error; 584 585 error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices); 586 if (error) 587 goto error_free_subvol_name; 588 589 error = btrfs_open_devices(fs_devices, mode, fs_type); 590 if (error) 591 goto error_free_subvol_name; 592 593 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) { 594 error = -EACCES; 595 goto error_close_devices; 596 } 597 598 bdev = fs_devices->latest_bdev; 599 s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices); 600 if (IS_ERR(s)) 601 goto error_s; 602 603 if (s->s_root) { 604 if ((flags ^ s->s_flags) & MS_RDONLY) { 605 deactivate_locked_super(s); 606 error = -EBUSY; 607 goto error_close_devices; 608 } 609 610 found = 1; 611 btrfs_close_devices(fs_devices); 612 } else { 613 char b[BDEVNAME_SIZE]; 614 615 s->s_flags = flags; 616 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); 617 error = btrfs_fill_super(s, fs_devices, data, 618 flags & MS_SILENT ? 1 : 0); 619 if (error) { 620 deactivate_locked_super(s); 621 goto error_free_subvol_name; 622 } 623 624 btrfs_sb(s)->fs_info->bdev_holder = fs_type; 625 s->s_flags |= MS_ACTIVE; 626 } 627 628 root = get_default_root(s, subvol_objectid); 629 if (IS_ERR(root)) { 630 error = PTR_ERR(root); 631 deactivate_locked_super(s); 632 goto error; 633 } 634 /* if they gave us a subvolume name bind mount into that */ 635 if (strcmp(subvol_name, ".")) { 636 struct dentry *new_root; 637 mutex_lock(&root->d_inode->i_mutex); 638 new_root = lookup_one_len(subvol_name, root, 639 strlen(subvol_name)); 640 mutex_unlock(&root->d_inode->i_mutex); 641 642 if (IS_ERR(new_root)) { 643 deactivate_locked_super(s); 644 error = PTR_ERR(new_root); 645 dput(root); 646 goto error_close_devices; 647 } 648 if (!new_root->d_inode) { 649 dput(root); 650 dput(new_root); 651 deactivate_locked_super(s); 652 error = -ENXIO; 653 goto error_close_devices; 654 } 655 dput(root); 656 root = new_root; 657 } 658 659 mnt->mnt_sb = s; 660 mnt->mnt_root = root; 661 662 kfree(subvol_name); 663 return 0; 664 665error_s: 666 error = PTR_ERR(s); 667error_close_devices: 668 btrfs_close_devices(fs_devices); 669error_free_subvol_name: 670 kfree(subvol_name); 671error: 672 return error; 673} 674 675static int btrfs_remount(struct super_block *sb, int *flags, char *data) 676{ 677 struct btrfs_root *root = btrfs_sb(sb); 678 int ret; 679 680 ret = btrfs_parse_options(root, data); 681 if (ret) 682 return -EINVAL; 683 684 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) 685 return 0; 686 687 if (*flags & MS_RDONLY) { 688 sb->s_flags |= MS_RDONLY; 689 690 ret = btrfs_commit_super(root); 691 WARN_ON(ret); 692 } else { 693 if (root->fs_info->fs_devices->rw_devices == 0) 694 return -EACCES; 695 696 if (btrfs_super_log_root(&root->fs_info->super_copy) != 0) 697 return -EINVAL; 698 699 ret = btrfs_cleanup_fs_roots(root->fs_info); 700 WARN_ON(ret); 701 702 /* recover relocation */ 703 ret = btrfs_recover_relocation(root); 704 WARN_ON(ret); 705 706 sb->s_flags &= ~MS_RDONLY; 707 } 708 709 return 0; 710} 711 712static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 713{ 714 struct btrfs_root *root = btrfs_sb(dentry->d_sb); 715 struct btrfs_super_block *disk_super = &root->fs_info->super_copy; 716 struct list_head *head = &root->fs_info->space_info; 717 struct btrfs_space_info *found; 718 u64 total_used = 0; 719 int bits = dentry->d_sb->s_blocksize_bits; 720 __be32 *fsid = (__be32 *)root->fs_info->fsid; 721 722 rcu_read_lock(); 723 list_for_each_entry_rcu(found, head, list) 724 total_used += found->disk_used; 725 rcu_read_unlock(); 726 727 buf->f_namelen = BTRFS_NAME_LEN; 728 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits; 729 buf->f_bfree = buf->f_blocks - (total_used >> bits); 730 buf->f_bavail = buf->f_bfree; 731 buf->f_bsize = dentry->d_sb->s_blocksize; 732 buf->f_type = BTRFS_SUPER_MAGIC; 733 734 /* We treat it as constant endianness (it doesn't matter _which_) 735 because we want the fsid to come out the same whether mounted 736 on a big-endian or little-endian host */ 737 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]); 738 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]); 739 /* Mask in the root object ID too, to disambiguate subvols */ 740 buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32; 741 buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid; 742 743 return 0; 744} 745 746static struct file_system_type btrfs_fs_type = { 747 .owner = THIS_MODULE, 748 .name = "btrfs", 749 .get_sb = btrfs_get_sb, 750 .kill_sb = kill_anon_super, 751 .fs_flags = FS_REQUIRES_DEV, 752}; 753 754/* 755 * used by btrfsctl to scan devices when no FS is mounted 756 */ 757static long btrfs_control_ioctl(struct file *file, unsigned int cmd, 758 unsigned long arg) 759{ 760 struct btrfs_ioctl_vol_args *vol; 761 struct btrfs_fs_devices *fs_devices; 762 int ret = -ENOTTY; 763 764 if (!capable(CAP_SYS_ADMIN)) 765 return -EPERM; 766 767 vol = memdup_user((void __user *)arg, sizeof(*vol)); 768 if (IS_ERR(vol)) 769 return PTR_ERR(vol); 770 771 switch (cmd) { 772 case BTRFS_IOC_SCAN_DEV: 773 ret = btrfs_scan_one_device(vol->name, FMODE_READ, 774 &btrfs_fs_type, &fs_devices); 775 break; 776 } 777 778 kfree(vol); 779 return ret; 780} 781 782static int btrfs_freeze(struct super_block *sb) 783{ 784 struct btrfs_root *root = btrfs_sb(sb); 785 mutex_lock(&root->fs_info->transaction_kthread_mutex); 786 mutex_lock(&root->fs_info->cleaner_mutex); 787 return 0; 788} 789 790static int btrfs_unfreeze(struct super_block *sb) 791{ 792 struct btrfs_root *root = btrfs_sb(sb); 793 mutex_unlock(&root->fs_info->cleaner_mutex); 794 mutex_unlock(&root->fs_info->transaction_kthread_mutex); 795 return 0; 796} 797 798static const struct super_operations btrfs_super_ops = { 799 .drop_inode = btrfs_drop_inode, 800 .evict_inode = btrfs_evict_inode, 801 .put_super = btrfs_put_super, 802 .sync_fs = btrfs_sync_fs, 803 .show_options = btrfs_show_options, 804 .write_inode = btrfs_write_inode, 805 .dirty_inode = btrfs_dirty_inode, 806 .alloc_inode = btrfs_alloc_inode, 807 .destroy_inode = btrfs_destroy_inode, 808 .statfs = btrfs_statfs, 809 .remount_fs = btrfs_remount, 810 .freeze_fs = btrfs_freeze, 811 .unfreeze_fs = btrfs_unfreeze, 812}; 813 814static const struct file_operations btrfs_ctl_fops = { 815 .unlocked_ioctl = btrfs_control_ioctl, 816 .compat_ioctl = btrfs_control_ioctl, 817 .owner = THIS_MODULE, 818}; 819 820static struct miscdevice btrfs_misc = { 821 .minor = BTRFS_MINOR, 822 .name = "btrfs-control", 823 .fops = &btrfs_ctl_fops 824}; 825 826MODULE_ALIAS_MISCDEV(BTRFS_MINOR); 827MODULE_ALIAS("devname:btrfs-control"); 828 829static int btrfs_interface_init(void) 830{ 831 return misc_register(&btrfs_misc); 832} 833 834static void btrfs_interface_exit(void) 835{ 836 if (misc_deregister(&btrfs_misc) < 0) 837 printk(KERN_INFO "misc_deregister failed for control device"); 838} 839 840static int __init init_btrfs_fs(void) 841{ 842 int err; 843 844 err = btrfs_init_sysfs(); 845 if (err) 846 return err; 847 848 err = btrfs_init_cachep(); 849 if (err) 850 goto free_sysfs; 851 852 err = extent_io_init(); 853 if (err) 854 goto free_cachep; 855 856 err = extent_map_init(); 857 if (err) 858 goto free_extent_io; 859 860 err = btrfs_interface_init(); 861 if (err) 862 goto free_extent_map; 863 864 err = register_filesystem(&btrfs_fs_type); 865 if (err) 866 goto unregister_ioctl; 867 868 printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION); 869 return 0; 870 871unregister_ioctl: 872 btrfs_interface_exit(); 873free_extent_map: 874 extent_map_exit(); 875free_extent_io: 876 extent_io_exit(); 877free_cachep: 878 btrfs_destroy_cachep(); 879free_sysfs: 880 btrfs_exit_sysfs(); 881 return err; 882} 883 884static void __exit exit_btrfs_fs(void) 885{ 886 btrfs_destroy_cachep(); 887 extent_map_exit(); 888 extent_io_exit(); 889 btrfs_interface_exit(); 890 unregister_filesystem(&btrfs_fs_type); 891 btrfs_exit_sysfs(); 892 btrfs_cleanup_fs_uuids(); 893 btrfs_zlib_exit(); 894} 895 896module_init(init_btrfs_fs) 897module_exit(exit_btrfs_fs) 898 899MODULE_LICENSE("GPL"); 900