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