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