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