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