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 <linux/ratelimit.h> 44 #include <linux/btrfs.h> 45 #include "compat.h" 46 #include "delayed-inode.h" 47 #include "ctree.h" 48 #include "disk-io.h" 49 #include "transaction.h" 50 #include "btrfs_inode.h" 51 #include "print-tree.h" 52 #include "xattr.h" 53 #include "volumes.h" 54 #include "export.h" 55 #include "compression.h" 56 #include "rcu-string.h" 57 #include "dev-replace.h" 58 #include "free-space-cache.h" 59 60 #define CREATE_TRACE_POINTS 61 #include <trace/events/btrfs.h> 62 63 static const struct super_operations btrfs_super_ops; 64 static struct file_system_type btrfs_fs_type; 65 66 static const char *btrfs_decode_error(int errno) 67 { 68 char *errstr = "unknown"; 69 70 switch (errno) { 71 case -EIO: 72 errstr = "IO failure"; 73 break; 74 case -ENOMEM: 75 errstr = "Out of memory"; 76 break; 77 case -EROFS: 78 errstr = "Readonly filesystem"; 79 break; 80 case -EEXIST: 81 errstr = "Object already exists"; 82 break; 83 case -ENOSPC: 84 errstr = "No space left"; 85 break; 86 case -ENOENT: 87 errstr = "No such entry"; 88 break; 89 } 90 91 return errstr; 92 } 93 94 static void save_error_info(struct btrfs_fs_info *fs_info) 95 { 96 /* 97 * today we only save the error info into ram. Long term we'll 98 * also send it down to the disk 99 */ 100 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state); 101 } 102 103 /* btrfs handle error by forcing the filesystem readonly */ 104 static void btrfs_handle_error(struct btrfs_fs_info *fs_info) 105 { 106 struct super_block *sb = fs_info->sb; 107 108 if (sb->s_flags & MS_RDONLY) 109 return; 110 111 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 112 sb->s_flags |= MS_RDONLY; 113 btrfs_info(fs_info, "forced readonly"); 114 /* 115 * Note that a running device replace operation is not 116 * canceled here although there is no way to update 117 * the progress. It would add the risk of a deadlock, 118 * therefore the canceling is ommited. The only penalty 119 * is that some I/O remains active until the procedure 120 * completes. The next time when the filesystem is 121 * mounted writeable again, the device replace 122 * operation continues. 123 */ 124 } 125 } 126 127 #ifdef CONFIG_PRINTK 128 /* 129 * __btrfs_std_error decodes expected errors from the caller and 130 * invokes the approciate error response. 131 */ 132 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, 133 unsigned int line, int errno, const char *fmt, ...) 134 { 135 struct super_block *sb = fs_info->sb; 136 const char *errstr; 137 138 /* 139 * Special case: if the error is EROFS, and we're already 140 * under MS_RDONLY, then it is safe here. 141 */ 142 if (errno == -EROFS && (sb->s_flags & MS_RDONLY)) 143 return; 144 145 errstr = btrfs_decode_error(errno); 146 if (fmt) { 147 struct va_format vaf; 148 va_list args; 149 150 va_start(args, fmt); 151 vaf.fmt = fmt; 152 vaf.va = &args; 153 154 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: errno=%d %s (%pV)\n", 155 sb->s_id, function, line, errno, errstr, &vaf); 156 va_end(args); 157 } else { 158 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: errno=%d %s\n", 159 sb->s_id, function, line, errno, errstr); 160 } 161 162 /* Don't go through full error handling during mount */ 163 save_error_info(fs_info); 164 if (sb->s_flags & MS_BORN) 165 btrfs_handle_error(fs_info); 166 } 167 168 static const char * const logtypes[] = { 169 "emergency", 170 "alert", 171 "critical", 172 "error", 173 "warning", 174 "notice", 175 "info", 176 "debug", 177 }; 178 179 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...) 180 { 181 struct super_block *sb = fs_info->sb; 182 char lvl[4]; 183 struct va_format vaf; 184 va_list args; 185 const char *type = logtypes[4]; 186 int kern_level; 187 188 va_start(args, fmt); 189 190 kern_level = printk_get_level(fmt); 191 if (kern_level) { 192 size_t size = printk_skip_level(fmt) - fmt; 193 memcpy(lvl, fmt, size); 194 lvl[size] = '\0'; 195 fmt += size; 196 type = logtypes[kern_level - '0']; 197 } else 198 *lvl = '\0'; 199 200 vaf.fmt = fmt; 201 vaf.va = &args; 202 203 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf); 204 205 va_end(args); 206 } 207 208 #else 209 210 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, 211 unsigned int line, int errno, const char *fmt, ...) 212 { 213 struct super_block *sb = fs_info->sb; 214 215 /* 216 * Special case: if the error is EROFS, and we're already 217 * under MS_RDONLY, then it is safe here. 218 */ 219 if (errno == -EROFS && (sb->s_flags & MS_RDONLY)) 220 return; 221 222 /* Don't go through full error handling during mount */ 223 if (sb->s_flags & MS_BORN) { 224 save_error_info(fs_info); 225 btrfs_handle_error(fs_info); 226 } 227 } 228 #endif 229 230 /* 231 * We only mark the transaction aborted and then set the file system read-only. 232 * This will prevent new transactions from starting or trying to join this 233 * one. 234 * 235 * This means that error recovery at the call site is limited to freeing 236 * any local memory allocations and passing the error code up without 237 * further cleanup. The transaction should complete as it normally would 238 * in the call path but will return -EIO. 239 * 240 * We'll complete the cleanup in btrfs_end_transaction and 241 * btrfs_commit_transaction. 242 */ 243 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans, 244 struct btrfs_root *root, const char *function, 245 unsigned int line, int errno) 246 { 247 /* 248 * Report first abort since mount 249 */ 250 if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED, 251 &root->fs_info->fs_state)) { 252 WARN(1, KERN_DEBUG "btrfs: Transaction aborted (error %d)\n", 253 errno); 254 } 255 trans->aborted = errno; 256 /* Nothing used. The other threads that have joined this 257 * transaction may be able to continue. */ 258 if (!trans->blocks_used) { 259 const char *errstr; 260 261 errstr = btrfs_decode_error(errno); 262 btrfs_warn(root->fs_info, 263 "%s:%d: Aborting unused transaction(%s).", 264 function, line, errstr); 265 return; 266 } 267 ACCESS_ONCE(trans->transaction->aborted) = errno; 268 /* Wake up anybody who may be waiting on this transaction */ 269 wake_up(&root->fs_info->transaction_wait); 270 wake_up(&root->fs_info->transaction_blocked_wait); 271 __btrfs_std_error(root->fs_info, function, line, errno, NULL); 272 } 273 /* 274 * __btrfs_panic decodes unexpected, fatal errors from the caller, 275 * issues an alert, and either panics or BUGs, depending on mount options. 276 */ 277 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function, 278 unsigned int line, int errno, const char *fmt, ...) 279 { 280 char *s_id = "<unknown>"; 281 const char *errstr; 282 struct va_format vaf = { .fmt = fmt }; 283 va_list args; 284 285 if (fs_info) 286 s_id = fs_info->sb->s_id; 287 288 va_start(args, fmt); 289 vaf.va = &args; 290 291 errstr = btrfs_decode_error(errno); 292 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR)) 293 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n", 294 s_id, function, line, &vaf, errno, errstr); 295 296 printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n", 297 s_id, function, line, &vaf, errno, errstr); 298 va_end(args); 299 /* Caller calls BUG() */ 300 } 301 302 static void btrfs_put_super(struct super_block *sb) 303 { 304 (void)close_ctree(btrfs_sb(sb)->tree_root); 305 /* FIXME: need to fix VFS to return error? */ 306 /* AV: return it _where_? ->put_super() can be triggered by any number 307 * of async events, up to and including delivery of SIGKILL to the 308 * last process that kept it busy. Or segfault in the aforementioned 309 * process... Whom would you report that to? 310 */ 311 } 312 313 enum { 314 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum, 315 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, 316 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress, 317 Opt_compress_type, Opt_compress_force, Opt_compress_force_type, 318 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard, 319 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed, 320 Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache, 321 Opt_no_space_cache, Opt_recovery, Opt_skip_balance, 322 Opt_check_integrity, Opt_check_integrity_including_extent_data, 323 Opt_check_integrity_print_mask, Opt_fatal_errors, 324 Opt_err, 325 }; 326 327 static match_table_t tokens = { 328 {Opt_degraded, "degraded"}, 329 {Opt_subvol, "subvol=%s"}, 330 {Opt_subvolid, "subvolid=%d"}, 331 {Opt_device, "device=%s"}, 332 {Opt_nodatasum, "nodatasum"}, 333 {Opt_nodatacow, "nodatacow"}, 334 {Opt_nobarrier, "nobarrier"}, 335 {Opt_max_inline, "max_inline=%s"}, 336 {Opt_alloc_start, "alloc_start=%s"}, 337 {Opt_thread_pool, "thread_pool=%d"}, 338 {Opt_compress, "compress"}, 339 {Opt_compress_type, "compress=%s"}, 340 {Opt_compress_force, "compress-force"}, 341 {Opt_compress_force_type, "compress-force=%s"}, 342 {Opt_ssd, "ssd"}, 343 {Opt_ssd_spread, "ssd_spread"}, 344 {Opt_nossd, "nossd"}, 345 {Opt_noacl, "noacl"}, 346 {Opt_notreelog, "notreelog"}, 347 {Opt_flushoncommit, "flushoncommit"}, 348 {Opt_ratio, "metadata_ratio=%d"}, 349 {Opt_discard, "discard"}, 350 {Opt_space_cache, "space_cache"}, 351 {Opt_clear_cache, "clear_cache"}, 352 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"}, 353 {Opt_enospc_debug, "enospc_debug"}, 354 {Opt_subvolrootid, "subvolrootid=%d"}, 355 {Opt_defrag, "autodefrag"}, 356 {Opt_inode_cache, "inode_cache"}, 357 {Opt_no_space_cache, "nospace_cache"}, 358 {Opt_recovery, "recovery"}, 359 {Opt_skip_balance, "skip_balance"}, 360 {Opt_check_integrity, "check_int"}, 361 {Opt_check_integrity_including_extent_data, "check_int_data"}, 362 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"}, 363 {Opt_fatal_errors, "fatal_errors=%s"}, 364 {Opt_err, NULL}, 365 }; 366 367 /* 368 * Regular mount options parser. Everything that is needed only when 369 * reading in a new superblock is parsed here. 370 * XXX JDM: This needs to be cleaned up for remount. 371 */ 372 int btrfs_parse_options(struct btrfs_root *root, char *options) 373 { 374 struct btrfs_fs_info *info = root->fs_info; 375 substring_t args[MAX_OPT_ARGS]; 376 char *p, *num, *orig = NULL; 377 u64 cache_gen; 378 int intarg; 379 int ret = 0; 380 char *compress_type; 381 bool compress_force = false; 382 383 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy); 384 if (cache_gen) 385 btrfs_set_opt(info->mount_opt, SPACE_CACHE); 386 387 if (!options) 388 goto out; 389 390 /* 391 * strsep changes the string, duplicate it because parse_options 392 * gets called twice 393 */ 394 options = kstrdup(options, GFP_NOFS); 395 if (!options) 396 return -ENOMEM; 397 398 orig = options; 399 400 while ((p = strsep(&options, ",")) != NULL) { 401 int token; 402 if (!*p) 403 continue; 404 405 token = match_token(p, tokens, args); 406 switch (token) { 407 case Opt_degraded: 408 printk(KERN_INFO "btrfs: allowing degraded mounts\n"); 409 btrfs_set_opt(info->mount_opt, DEGRADED); 410 break; 411 case Opt_subvol: 412 case Opt_subvolid: 413 case Opt_subvolrootid: 414 case Opt_device: 415 /* 416 * These are parsed by btrfs_parse_early_options 417 * and can be happily ignored here. 418 */ 419 break; 420 case Opt_nodatasum: 421 printk(KERN_INFO "btrfs: setting nodatasum\n"); 422 btrfs_set_opt(info->mount_opt, NODATASUM); 423 break; 424 case Opt_nodatacow: 425 if (!btrfs_test_opt(root, COMPRESS) || 426 !btrfs_test_opt(root, FORCE_COMPRESS)) { 427 printk(KERN_INFO "btrfs: setting nodatacow, compression disabled\n"); 428 } else { 429 printk(KERN_INFO "btrfs: setting nodatacow\n"); 430 } 431 info->compress_type = BTRFS_COMPRESS_NONE; 432 btrfs_clear_opt(info->mount_opt, COMPRESS); 433 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS); 434 btrfs_set_opt(info->mount_opt, NODATACOW); 435 btrfs_set_opt(info->mount_opt, NODATASUM); 436 break; 437 case Opt_compress_force: 438 case Opt_compress_force_type: 439 compress_force = true; 440 /* Fallthrough */ 441 case Opt_compress: 442 case Opt_compress_type: 443 if (token == Opt_compress || 444 token == Opt_compress_force || 445 strcmp(args[0].from, "zlib") == 0) { 446 compress_type = "zlib"; 447 info->compress_type = BTRFS_COMPRESS_ZLIB; 448 btrfs_set_opt(info->mount_opt, COMPRESS); 449 btrfs_clear_opt(info->mount_opt, NODATACOW); 450 btrfs_clear_opt(info->mount_opt, NODATASUM); 451 } else if (strcmp(args[0].from, "lzo") == 0) { 452 compress_type = "lzo"; 453 info->compress_type = BTRFS_COMPRESS_LZO; 454 btrfs_set_opt(info->mount_opt, COMPRESS); 455 btrfs_clear_opt(info->mount_opt, NODATACOW); 456 btrfs_clear_opt(info->mount_opt, NODATASUM); 457 btrfs_set_fs_incompat(info, COMPRESS_LZO); 458 } else if (strncmp(args[0].from, "no", 2) == 0) { 459 compress_type = "no"; 460 info->compress_type = BTRFS_COMPRESS_NONE; 461 btrfs_clear_opt(info->mount_opt, COMPRESS); 462 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS); 463 compress_force = false; 464 } else { 465 ret = -EINVAL; 466 goto out; 467 } 468 469 if (compress_force) { 470 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS); 471 pr_info("btrfs: force %s compression\n", 472 compress_type); 473 } else 474 pr_info("btrfs: use %s compression\n", 475 compress_type); 476 break; 477 case Opt_ssd: 478 printk(KERN_INFO "btrfs: use ssd allocation scheme\n"); 479 btrfs_set_opt(info->mount_opt, SSD); 480 break; 481 case Opt_ssd_spread: 482 printk(KERN_INFO "btrfs: use spread ssd " 483 "allocation scheme\n"); 484 btrfs_set_opt(info->mount_opt, SSD); 485 btrfs_set_opt(info->mount_opt, SSD_SPREAD); 486 break; 487 case Opt_nossd: 488 printk(KERN_INFO "btrfs: not using ssd allocation " 489 "scheme\n"); 490 btrfs_set_opt(info->mount_opt, NOSSD); 491 btrfs_clear_opt(info->mount_opt, SSD); 492 btrfs_clear_opt(info->mount_opt, SSD_SPREAD); 493 break; 494 case Opt_nobarrier: 495 printk(KERN_INFO "btrfs: turning off barriers\n"); 496 btrfs_set_opt(info->mount_opt, NOBARRIER); 497 break; 498 case Opt_thread_pool: 499 intarg = 0; 500 match_int(&args[0], &intarg); 501 if (intarg) 502 info->thread_pool_size = intarg; 503 break; 504 case Opt_max_inline: 505 num = match_strdup(&args[0]); 506 if (num) { 507 info->max_inline = memparse(num, NULL); 508 kfree(num); 509 510 if (info->max_inline) { 511 info->max_inline = max_t(u64, 512 info->max_inline, 513 root->sectorsize); 514 } 515 printk(KERN_INFO "btrfs: max_inline at %llu\n", 516 (unsigned long long)info->max_inline); 517 } 518 break; 519 case Opt_alloc_start: 520 num = match_strdup(&args[0]); 521 if (num) { 522 mutex_lock(&info->chunk_mutex); 523 info->alloc_start = memparse(num, NULL); 524 mutex_unlock(&info->chunk_mutex); 525 kfree(num); 526 printk(KERN_INFO 527 "btrfs: allocations start at %llu\n", 528 (unsigned long long)info->alloc_start); 529 } 530 break; 531 case Opt_noacl: 532 root->fs_info->sb->s_flags &= ~MS_POSIXACL; 533 break; 534 case Opt_notreelog: 535 printk(KERN_INFO "btrfs: disabling tree log\n"); 536 btrfs_set_opt(info->mount_opt, NOTREELOG); 537 break; 538 case Opt_flushoncommit: 539 printk(KERN_INFO "btrfs: turning on flush-on-commit\n"); 540 btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT); 541 break; 542 case Opt_ratio: 543 intarg = 0; 544 match_int(&args[0], &intarg); 545 if (intarg) { 546 info->metadata_ratio = intarg; 547 printk(KERN_INFO "btrfs: metadata ratio %d\n", 548 info->metadata_ratio); 549 } 550 break; 551 case Opt_discard: 552 btrfs_set_opt(info->mount_opt, DISCARD); 553 break; 554 case Opt_space_cache: 555 btrfs_set_opt(info->mount_opt, SPACE_CACHE); 556 break; 557 case Opt_no_space_cache: 558 printk(KERN_INFO "btrfs: disabling disk space caching\n"); 559 btrfs_clear_opt(info->mount_opt, SPACE_CACHE); 560 break; 561 case Opt_inode_cache: 562 printk(KERN_INFO "btrfs: enabling inode map caching\n"); 563 btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE); 564 break; 565 case Opt_clear_cache: 566 printk(KERN_INFO "btrfs: force clearing of disk cache\n"); 567 btrfs_set_opt(info->mount_opt, CLEAR_CACHE); 568 break; 569 case Opt_user_subvol_rm_allowed: 570 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED); 571 break; 572 case Opt_enospc_debug: 573 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG); 574 break; 575 case Opt_defrag: 576 printk(KERN_INFO "btrfs: enabling auto defrag\n"); 577 btrfs_set_opt(info->mount_opt, AUTO_DEFRAG); 578 break; 579 case Opt_recovery: 580 printk(KERN_INFO "btrfs: enabling auto recovery\n"); 581 btrfs_set_opt(info->mount_opt, RECOVERY); 582 break; 583 case Opt_skip_balance: 584 btrfs_set_opt(info->mount_opt, SKIP_BALANCE); 585 break; 586 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY 587 case Opt_check_integrity_including_extent_data: 588 printk(KERN_INFO "btrfs: enabling check integrity" 589 " including extent data\n"); 590 btrfs_set_opt(info->mount_opt, 591 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA); 592 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY); 593 break; 594 case Opt_check_integrity: 595 printk(KERN_INFO "btrfs: enabling check integrity\n"); 596 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY); 597 break; 598 case Opt_check_integrity_print_mask: 599 intarg = 0; 600 match_int(&args[0], &intarg); 601 if (intarg) { 602 info->check_integrity_print_mask = intarg; 603 printk(KERN_INFO "btrfs:" 604 " check_integrity_print_mask 0x%x\n", 605 info->check_integrity_print_mask); 606 } 607 break; 608 #else 609 case Opt_check_integrity_including_extent_data: 610 case Opt_check_integrity: 611 case Opt_check_integrity_print_mask: 612 printk(KERN_ERR "btrfs: support for check_integrity*" 613 " not compiled in!\n"); 614 ret = -EINVAL; 615 goto out; 616 #endif 617 case Opt_fatal_errors: 618 if (strcmp(args[0].from, "panic") == 0) 619 btrfs_set_opt(info->mount_opt, 620 PANIC_ON_FATAL_ERROR); 621 else if (strcmp(args[0].from, "bug") == 0) 622 btrfs_clear_opt(info->mount_opt, 623 PANIC_ON_FATAL_ERROR); 624 else { 625 ret = -EINVAL; 626 goto out; 627 } 628 break; 629 case Opt_err: 630 printk(KERN_INFO "btrfs: unrecognized mount option " 631 "'%s'\n", p); 632 ret = -EINVAL; 633 goto out; 634 default: 635 break; 636 } 637 } 638 out: 639 if (!ret && btrfs_test_opt(root, SPACE_CACHE)) 640 printk(KERN_INFO "btrfs: disk space caching is enabled\n"); 641 kfree(orig); 642 return ret; 643 } 644 645 /* 646 * Parse mount options that are required early in the mount process. 647 * 648 * All other options will be parsed on much later in the mount process and 649 * only when we need to allocate a new super block. 650 */ 651 static int btrfs_parse_early_options(const char *options, fmode_t flags, 652 void *holder, char **subvol_name, u64 *subvol_objectid, 653 struct btrfs_fs_devices **fs_devices) 654 { 655 substring_t args[MAX_OPT_ARGS]; 656 char *device_name, *opts, *orig, *p; 657 int error = 0; 658 int intarg; 659 660 if (!options) 661 return 0; 662 663 /* 664 * strsep changes the string, duplicate it because parse_options 665 * gets called twice 666 */ 667 opts = kstrdup(options, GFP_KERNEL); 668 if (!opts) 669 return -ENOMEM; 670 orig = opts; 671 672 while ((p = strsep(&opts, ",")) != NULL) { 673 int token; 674 if (!*p) 675 continue; 676 677 token = match_token(p, tokens, args); 678 switch (token) { 679 case Opt_subvol: 680 kfree(*subvol_name); 681 *subvol_name = match_strdup(&args[0]); 682 break; 683 case Opt_subvolid: 684 intarg = 0; 685 error = match_int(&args[0], &intarg); 686 if (!error) { 687 /* we want the original fs_tree */ 688 if (!intarg) 689 *subvol_objectid = 690 BTRFS_FS_TREE_OBJECTID; 691 else 692 *subvol_objectid = intarg; 693 } 694 break; 695 case Opt_subvolrootid: 696 printk(KERN_WARNING 697 "btrfs: 'subvolrootid' mount option is deprecated and has no effect\n"); 698 break; 699 case Opt_device: 700 device_name = match_strdup(&args[0]); 701 if (!device_name) { 702 error = -ENOMEM; 703 goto out; 704 } 705 error = btrfs_scan_one_device(device_name, 706 flags, holder, fs_devices); 707 kfree(device_name); 708 if (error) 709 goto out; 710 break; 711 default: 712 break; 713 } 714 } 715 716 out: 717 kfree(orig); 718 return error; 719 } 720 721 static struct dentry *get_default_root(struct super_block *sb, 722 u64 subvol_objectid) 723 { 724 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 725 struct btrfs_root *root = fs_info->tree_root; 726 struct btrfs_root *new_root; 727 struct btrfs_dir_item *di; 728 struct btrfs_path *path; 729 struct btrfs_key location; 730 struct inode *inode; 731 u64 dir_id; 732 int new = 0; 733 734 /* 735 * We have a specific subvol we want to mount, just setup location and 736 * go look up the root. 737 */ 738 if (subvol_objectid) { 739 location.objectid = subvol_objectid; 740 location.type = BTRFS_ROOT_ITEM_KEY; 741 location.offset = (u64)-1; 742 goto find_root; 743 } 744 745 path = btrfs_alloc_path(); 746 if (!path) 747 return ERR_PTR(-ENOMEM); 748 path->leave_spinning = 1; 749 750 /* 751 * Find the "default" dir item which points to the root item that we 752 * will mount by default if we haven't been given a specific subvolume 753 * to mount. 754 */ 755 dir_id = btrfs_super_root_dir(fs_info->super_copy); 756 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0); 757 if (IS_ERR(di)) { 758 btrfs_free_path(path); 759 return ERR_CAST(di); 760 } 761 if (!di) { 762 /* 763 * Ok the default dir item isn't there. This is weird since 764 * it's always been there, but don't freak out, just try and 765 * mount to root most subvolume. 766 */ 767 btrfs_free_path(path); 768 dir_id = BTRFS_FIRST_FREE_OBJECTID; 769 new_root = fs_info->fs_root; 770 goto setup_root; 771 } 772 773 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); 774 btrfs_free_path(path); 775 776 find_root: 777 new_root = btrfs_read_fs_root_no_name(fs_info, &location); 778 if (IS_ERR(new_root)) 779 return ERR_CAST(new_root); 780 781 dir_id = btrfs_root_dirid(&new_root->root_item); 782 setup_root: 783 location.objectid = dir_id; 784 location.type = BTRFS_INODE_ITEM_KEY; 785 location.offset = 0; 786 787 inode = btrfs_iget(sb, &location, new_root, &new); 788 if (IS_ERR(inode)) 789 return ERR_CAST(inode); 790 791 /* 792 * If we're just mounting the root most subvol put the inode and return 793 * a reference to the dentry. We will have already gotten a reference 794 * to the inode in btrfs_fill_super so we're good to go. 795 */ 796 if (!new && sb->s_root->d_inode == inode) { 797 iput(inode); 798 return dget(sb->s_root); 799 } 800 801 return d_obtain_alias(inode); 802 } 803 804 static int btrfs_fill_super(struct super_block *sb, 805 struct btrfs_fs_devices *fs_devices, 806 void *data, int silent) 807 { 808 struct inode *inode; 809 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 810 struct btrfs_key key; 811 int err; 812 813 sb->s_maxbytes = MAX_LFS_FILESIZE; 814 sb->s_magic = BTRFS_SUPER_MAGIC; 815 sb->s_op = &btrfs_super_ops; 816 sb->s_d_op = &btrfs_dentry_operations; 817 sb->s_export_op = &btrfs_export_ops; 818 sb->s_xattr = btrfs_xattr_handlers; 819 sb->s_time_gran = 1; 820 #ifdef CONFIG_BTRFS_FS_POSIX_ACL 821 sb->s_flags |= MS_POSIXACL; 822 #endif 823 sb->s_flags |= MS_I_VERSION; 824 err = open_ctree(sb, fs_devices, (char *)data); 825 if (err) { 826 printk("btrfs: open_ctree failed\n"); 827 return err; 828 } 829 830 key.objectid = BTRFS_FIRST_FREE_OBJECTID; 831 key.type = BTRFS_INODE_ITEM_KEY; 832 key.offset = 0; 833 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL); 834 if (IS_ERR(inode)) { 835 err = PTR_ERR(inode); 836 goto fail_close; 837 } 838 839 sb->s_root = d_make_root(inode); 840 if (!sb->s_root) { 841 err = -ENOMEM; 842 goto fail_close; 843 } 844 845 save_mount_options(sb, data); 846 cleancache_init_fs(sb); 847 sb->s_flags |= MS_ACTIVE; 848 return 0; 849 850 fail_close: 851 close_ctree(fs_info->tree_root); 852 return err; 853 } 854 855 int btrfs_sync_fs(struct super_block *sb, int wait) 856 { 857 struct btrfs_trans_handle *trans; 858 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 859 struct btrfs_root *root = fs_info->tree_root; 860 861 trace_btrfs_sync_fs(wait); 862 863 if (!wait) { 864 filemap_flush(fs_info->btree_inode->i_mapping); 865 return 0; 866 } 867 868 btrfs_wait_all_ordered_extents(fs_info, 1); 869 870 trans = btrfs_attach_transaction_barrier(root); 871 if (IS_ERR(trans)) { 872 /* no transaction, don't bother */ 873 if (PTR_ERR(trans) == -ENOENT) 874 return 0; 875 return PTR_ERR(trans); 876 } 877 return btrfs_commit_transaction(trans, root); 878 } 879 880 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) 881 { 882 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb); 883 struct btrfs_root *root = info->tree_root; 884 char *compress_type; 885 886 if (btrfs_test_opt(root, DEGRADED)) 887 seq_puts(seq, ",degraded"); 888 if (btrfs_test_opt(root, NODATASUM)) 889 seq_puts(seq, ",nodatasum"); 890 if (btrfs_test_opt(root, NODATACOW)) 891 seq_puts(seq, ",nodatacow"); 892 if (btrfs_test_opt(root, NOBARRIER)) 893 seq_puts(seq, ",nobarrier"); 894 if (info->max_inline != 8192 * 1024) 895 seq_printf(seq, ",max_inline=%llu", 896 (unsigned long long)info->max_inline); 897 if (info->alloc_start != 0) 898 seq_printf(seq, ",alloc_start=%llu", 899 (unsigned long long)info->alloc_start); 900 if (info->thread_pool_size != min_t(unsigned long, 901 num_online_cpus() + 2, 8)) 902 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size); 903 if (btrfs_test_opt(root, COMPRESS)) { 904 if (info->compress_type == BTRFS_COMPRESS_ZLIB) 905 compress_type = "zlib"; 906 else 907 compress_type = "lzo"; 908 if (btrfs_test_opt(root, FORCE_COMPRESS)) 909 seq_printf(seq, ",compress-force=%s", compress_type); 910 else 911 seq_printf(seq, ",compress=%s", compress_type); 912 } 913 if (btrfs_test_opt(root, NOSSD)) 914 seq_puts(seq, ",nossd"); 915 if (btrfs_test_opt(root, SSD_SPREAD)) 916 seq_puts(seq, ",ssd_spread"); 917 else if (btrfs_test_opt(root, SSD)) 918 seq_puts(seq, ",ssd"); 919 if (btrfs_test_opt(root, NOTREELOG)) 920 seq_puts(seq, ",notreelog"); 921 if (btrfs_test_opt(root, FLUSHONCOMMIT)) 922 seq_puts(seq, ",flushoncommit"); 923 if (btrfs_test_opt(root, DISCARD)) 924 seq_puts(seq, ",discard"); 925 if (!(root->fs_info->sb->s_flags & MS_POSIXACL)) 926 seq_puts(seq, ",noacl"); 927 if (btrfs_test_opt(root, SPACE_CACHE)) 928 seq_puts(seq, ",space_cache"); 929 else 930 seq_puts(seq, ",nospace_cache"); 931 if (btrfs_test_opt(root, CLEAR_CACHE)) 932 seq_puts(seq, ",clear_cache"); 933 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED)) 934 seq_puts(seq, ",user_subvol_rm_allowed"); 935 if (btrfs_test_opt(root, ENOSPC_DEBUG)) 936 seq_puts(seq, ",enospc_debug"); 937 if (btrfs_test_opt(root, AUTO_DEFRAG)) 938 seq_puts(seq, ",autodefrag"); 939 if (btrfs_test_opt(root, INODE_MAP_CACHE)) 940 seq_puts(seq, ",inode_cache"); 941 if (btrfs_test_opt(root, SKIP_BALANCE)) 942 seq_puts(seq, ",skip_balance"); 943 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR)) 944 seq_puts(seq, ",fatal_errors=panic"); 945 return 0; 946 } 947 948 static int btrfs_test_super(struct super_block *s, void *data) 949 { 950 struct btrfs_fs_info *p = data; 951 struct btrfs_fs_info *fs_info = btrfs_sb(s); 952 953 return fs_info->fs_devices == p->fs_devices; 954 } 955 956 static int btrfs_set_super(struct super_block *s, void *data) 957 { 958 int err = set_anon_super(s, data); 959 if (!err) 960 s->s_fs_info = data; 961 return err; 962 } 963 964 /* 965 * subvolumes are identified by ino 256 966 */ 967 static inline int is_subvolume_inode(struct inode *inode) 968 { 969 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) 970 return 1; 971 return 0; 972 } 973 974 /* 975 * This will strip out the subvol=%s argument for an argument string and add 976 * subvolid=0 to make sure we get the actual tree root for path walking to the 977 * subvol we want. 978 */ 979 static char *setup_root_args(char *args) 980 { 981 unsigned len = strlen(args) + 2 + 1; 982 char *src, *dst, *buf; 983 984 /* 985 * We need the same args as before, but with this substitution: 986 * s!subvol=[^,]+!subvolid=0! 987 * 988 * Since the replacement string is up to 2 bytes longer than the 989 * original, allocate strlen(args) + 2 + 1 bytes. 990 */ 991 992 src = strstr(args, "subvol="); 993 /* This shouldn't happen, but just in case.. */ 994 if (!src) 995 return NULL; 996 997 buf = dst = kmalloc(len, GFP_NOFS); 998 if (!buf) 999 return NULL; 1000 1001 /* 1002 * If the subvol= arg is not at the start of the string, 1003 * copy whatever precedes it into buf. 1004 */ 1005 if (src != args) { 1006 *src++ = '\0'; 1007 strcpy(buf, args); 1008 dst += strlen(args); 1009 } 1010 1011 strcpy(dst, "subvolid=0"); 1012 dst += strlen("subvolid=0"); 1013 1014 /* 1015 * If there is a "," after the original subvol=... string, 1016 * copy that suffix into our buffer. Otherwise, we're done. 1017 */ 1018 src = strchr(src, ','); 1019 if (src) 1020 strcpy(dst, src); 1021 1022 return buf; 1023 } 1024 1025 static struct dentry *mount_subvol(const char *subvol_name, int flags, 1026 const char *device_name, char *data) 1027 { 1028 struct dentry *root; 1029 struct vfsmount *mnt; 1030 char *newargs; 1031 1032 newargs = setup_root_args(data); 1033 if (!newargs) 1034 return ERR_PTR(-ENOMEM); 1035 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, 1036 newargs); 1037 kfree(newargs); 1038 if (IS_ERR(mnt)) 1039 return ERR_CAST(mnt); 1040 1041 root = mount_subtree(mnt, subvol_name); 1042 1043 if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) { 1044 struct super_block *s = root->d_sb; 1045 dput(root); 1046 root = ERR_PTR(-EINVAL); 1047 deactivate_locked_super(s); 1048 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n", 1049 subvol_name); 1050 } 1051 1052 return root; 1053 } 1054 1055 /* 1056 * Find a superblock for the given device / mount point. 1057 * 1058 * Note: This is based on get_sb_bdev from fs/super.c with a few additions 1059 * for multiple device setup. Make sure to keep it in sync. 1060 */ 1061 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, 1062 const char *device_name, void *data) 1063 { 1064 struct block_device *bdev = NULL; 1065 struct super_block *s; 1066 struct dentry *root; 1067 struct btrfs_fs_devices *fs_devices = NULL; 1068 struct btrfs_fs_info *fs_info = NULL; 1069 fmode_t mode = FMODE_READ; 1070 char *subvol_name = NULL; 1071 u64 subvol_objectid = 0; 1072 int error = 0; 1073 1074 if (!(flags & MS_RDONLY)) 1075 mode |= FMODE_WRITE; 1076 1077 error = btrfs_parse_early_options(data, mode, fs_type, 1078 &subvol_name, &subvol_objectid, 1079 &fs_devices); 1080 if (error) { 1081 kfree(subvol_name); 1082 return ERR_PTR(error); 1083 } 1084 1085 if (subvol_name) { 1086 root = mount_subvol(subvol_name, flags, device_name, data); 1087 kfree(subvol_name); 1088 return root; 1089 } 1090 1091 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices); 1092 if (error) 1093 return ERR_PTR(error); 1094 1095 /* 1096 * Setup a dummy root and fs_info for test/set super. This is because 1097 * we don't actually fill this stuff out until open_ctree, but we need 1098 * it for searching for existing supers, so this lets us do that and 1099 * then open_ctree will properly initialize everything later. 1100 */ 1101 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS); 1102 if (!fs_info) 1103 return ERR_PTR(-ENOMEM); 1104 1105 fs_info->fs_devices = fs_devices; 1106 1107 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS); 1108 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS); 1109 if (!fs_info->super_copy || !fs_info->super_for_commit) { 1110 error = -ENOMEM; 1111 goto error_fs_info; 1112 } 1113 1114 error = btrfs_open_devices(fs_devices, mode, fs_type); 1115 if (error) 1116 goto error_fs_info; 1117 1118 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) { 1119 error = -EACCES; 1120 goto error_close_devices; 1121 } 1122 1123 bdev = fs_devices->latest_bdev; 1124 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC, 1125 fs_info); 1126 if (IS_ERR(s)) { 1127 error = PTR_ERR(s); 1128 goto error_close_devices; 1129 } 1130 1131 if (s->s_root) { 1132 btrfs_close_devices(fs_devices); 1133 free_fs_info(fs_info); 1134 if ((flags ^ s->s_flags) & MS_RDONLY) 1135 error = -EBUSY; 1136 } else { 1137 char b[BDEVNAME_SIZE]; 1138 1139 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); 1140 btrfs_sb(s)->bdev_holder = fs_type; 1141 error = btrfs_fill_super(s, fs_devices, data, 1142 flags & MS_SILENT ? 1 : 0); 1143 } 1144 1145 root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error); 1146 if (IS_ERR(root)) 1147 deactivate_locked_super(s); 1148 1149 return root; 1150 1151 error_close_devices: 1152 btrfs_close_devices(fs_devices); 1153 error_fs_info: 1154 free_fs_info(fs_info); 1155 return ERR_PTR(error); 1156 } 1157 1158 static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit) 1159 { 1160 spin_lock_irq(&workers->lock); 1161 workers->max_workers = new_limit; 1162 spin_unlock_irq(&workers->lock); 1163 } 1164 1165 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info, 1166 int new_pool_size, int old_pool_size) 1167 { 1168 if (new_pool_size == old_pool_size) 1169 return; 1170 1171 fs_info->thread_pool_size = new_pool_size; 1172 1173 printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n", 1174 old_pool_size, new_pool_size); 1175 1176 btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size); 1177 btrfs_set_max_workers(&fs_info->workers, new_pool_size); 1178 btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size); 1179 btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size); 1180 btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size); 1181 btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size); 1182 btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size); 1183 btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size); 1184 btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size); 1185 btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size); 1186 btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size); 1187 btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size); 1188 btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size); 1189 btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers, 1190 new_pool_size); 1191 } 1192 1193 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info) 1194 { 1195 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state); 1196 } 1197 1198 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info, 1199 unsigned long old_opts, int flags) 1200 { 1201 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) && 1202 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || 1203 (flags & MS_RDONLY))) { 1204 /* wait for any defraggers to finish */ 1205 wait_event(fs_info->transaction_wait, 1206 (atomic_read(&fs_info->defrag_running) == 0)); 1207 if (flags & MS_RDONLY) 1208 sync_filesystem(fs_info->sb); 1209 } 1210 } 1211 1212 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info, 1213 unsigned long old_opts) 1214 { 1215 /* 1216 * We need cleanup all defragable inodes if the autodefragment is 1217 * close or the fs is R/O. 1218 */ 1219 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) && 1220 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || 1221 (fs_info->sb->s_flags & MS_RDONLY))) { 1222 btrfs_cleanup_defrag_inodes(fs_info); 1223 } 1224 1225 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state); 1226 } 1227 1228 static int btrfs_remount(struct super_block *sb, int *flags, char *data) 1229 { 1230 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1231 struct btrfs_root *root = fs_info->tree_root; 1232 unsigned old_flags = sb->s_flags; 1233 unsigned long old_opts = fs_info->mount_opt; 1234 unsigned long old_compress_type = fs_info->compress_type; 1235 u64 old_max_inline = fs_info->max_inline; 1236 u64 old_alloc_start = fs_info->alloc_start; 1237 int old_thread_pool_size = fs_info->thread_pool_size; 1238 unsigned int old_metadata_ratio = fs_info->metadata_ratio; 1239 int ret; 1240 1241 btrfs_remount_prepare(fs_info); 1242 1243 ret = btrfs_parse_options(root, data); 1244 if (ret) { 1245 ret = -EINVAL; 1246 goto restore; 1247 } 1248 1249 btrfs_remount_begin(fs_info, old_opts, *flags); 1250 btrfs_resize_thread_pool(fs_info, 1251 fs_info->thread_pool_size, old_thread_pool_size); 1252 1253 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) 1254 goto out; 1255 1256 if (*flags & MS_RDONLY) { 1257 /* 1258 * this also happens on 'umount -rf' or on shutdown, when 1259 * the filesystem is busy. 1260 */ 1261 sb->s_flags |= MS_RDONLY; 1262 1263 btrfs_dev_replace_suspend_for_unmount(fs_info); 1264 btrfs_scrub_cancel(fs_info); 1265 btrfs_pause_balance(fs_info); 1266 1267 ret = btrfs_commit_super(root); 1268 if (ret) 1269 goto restore; 1270 } else { 1271 if (fs_info->fs_devices->rw_devices == 0) { 1272 ret = -EACCES; 1273 goto restore; 1274 } 1275 1276 if (fs_info->fs_devices->missing_devices > 1277 fs_info->num_tolerated_disk_barrier_failures && 1278 !(*flags & MS_RDONLY)) { 1279 printk(KERN_WARNING 1280 "Btrfs: too many missing devices, writeable remount is not allowed\n"); 1281 ret = -EACCES; 1282 goto restore; 1283 } 1284 1285 if (btrfs_super_log_root(fs_info->super_copy) != 0) { 1286 ret = -EINVAL; 1287 goto restore; 1288 } 1289 1290 ret = btrfs_cleanup_fs_roots(fs_info); 1291 if (ret) 1292 goto restore; 1293 1294 /* recover relocation */ 1295 ret = btrfs_recover_relocation(root); 1296 if (ret) 1297 goto restore; 1298 1299 ret = btrfs_resume_balance_async(fs_info); 1300 if (ret) 1301 goto restore; 1302 1303 ret = btrfs_resume_dev_replace_async(fs_info); 1304 if (ret) { 1305 pr_warn("btrfs: failed to resume dev_replace\n"); 1306 goto restore; 1307 } 1308 sb->s_flags &= ~MS_RDONLY; 1309 } 1310 out: 1311 btrfs_remount_cleanup(fs_info, old_opts); 1312 return 0; 1313 1314 restore: 1315 /* We've hit an error - don't reset MS_RDONLY */ 1316 if (sb->s_flags & MS_RDONLY) 1317 old_flags |= MS_RDONLY; 1318 sb->s_flags = old_flags; 1319 fs_info->mount_opt = old_opts; 1320 fs_info->compress_type = old_compress_type; 1321 fs_info->max_inline = old_max_inline; 1322 mutex_lock(&fs_info->chunk_mutex); 1323 fs_info->alloc_start = old_alloc_start; 1324 mutex_unlock(&fs_info->chunk_mutex); 1325 btrfs_resize_thread_pool(fs_info, 1326 old_thread_pool_size, fs_info->thread_pool_size); 1327 fs_info->metadata_ratio = old_metadata_ratio; 1328 btrfs_remount_cleanup(fs_info, old_opts); 1329 return ret; 1330 } 1331 1332 /* Used to sort the devices by max_avail(descending sort) */ 1333 static int btrfs_cmp_device_free_bytes(const void *dev_info1, 1334 const void *dev_info2) 1335 { 1336 if (((struct btrfs_device_info *)dev_info1)->max_avail > 1337 ((struct btrfs_device_info *)dev_info2)->max_avail) 1338 return -1; 1339 else if (((struct btrfs_device_info *)dev_info1)->max_avail < 1340 ((struct btrfs_device_info *)dev_info2)->max_avail) 1341 return 1; 1342 else 1343 return 0; 1344 } 1345 1346 /* 1347 * sort the devices by max_avail, in which max free extent size of each device 1348 * is stored.(Descending Sort) 1349 */ 1350 static inline void btrfs_descending_sort_devices( 1351 struct btrfs_device_info *devices, 1352 size_t nr_devices) 1353 { 1354 sort(devices, nr_devices, sizeof(struct btrfs_device_info), 1355 btrfs_cmp_device_free_bytes, NULL); 1356 } 1357 1358 /* 1359 * The helper to calc the free space on the devices that can be used to store 1360 * file data. 1361 */ 1362 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) 1363 { 1364 struct btrfs_fs_info *fs_info = root->fs_info; 1365 struct btrfs_device_info *devices_info; 1366 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; 1367 struct btrfs_device *device; 1368 u64 skip_space; 1369 u64 type; 1370 u64 avail_space; 1371 u64 used_space; 1372 u64 min_stripe_size; 1373 int min_stripes = 1, num_stripes = 1; 1374 int i = 0, nr_devices; 1375 int ret; 1376 1377 nr_devices = fs_info->fs_devices->open_devices; 1378 BUG_ON(!nr_devices); 1379 1380 devices_info = kmalloc(sizeof(*devices_info) * nr_devices, 1381 GFP_NOFS); 1382 if (!devices_info) 1383 return -ENOMEM; 1384 1385 /* calc min stripe number for data space alloction */ 1386 type = btrfs_get_alloc_profile(root, 1); 1387 if (type & BTRFS_BLOCK_GROUP_RAID0) { 1388 min_stripes = 2; 1389 num_stripes = nr_devices; 1390 } else if (type & BTRFS_BLOCK_GROUP_RAID1) { 1391 min_stripes = 2; 1392 num_stripes = 2; 1393 } else if (type & BTRFS_BLOCK_GROUP_RAID10) { 1394 min_stripes = 4; 1395 num_stripes = 4; 1396 } 1397 1398 if (type & BTRFS_BLOCK_GROUP_DUP) 1399 min_stripe_size = 2 * BTRFS_STRIPE_LEN; 1400 else 1401 min_stripe_size = BTRFS_STRIPE_LEN; 1402 1403 list_for_each_entry(device, &fs_devices->devices, dev_list) { 1404 if (!device->in_fs_metadata || !device->bdev || 1405 device->is_tgtdev_for_dev_replace) 1406 continue; 1407 1408 avail_space = device->total_bytes - device->bytes_used; 1409 1410 /* align with stripe_len */ 1411 do_div(avail_space, BTRFS_STRIPE_LEN); 1412 avail_space *= BTRFS_STRIPE_LEN; 1413 1414 /* 1415 * In order to avoid overwritting the superblock on the drive, 1416 * btrfs starts at an offset of at least 1MB when doing chunk 1417 * allocation. 1418 */ 1419 skip_space = 1024 * 1024; 1420 1421 /* user can set the offset in fs_info->alloc_start. */ 1422 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <= 1423 device->total_bytes) 1424 skip_space = max(fs_info->alloc_start, skip_space); 1425 1426 /* 1427 * btrfs can not use the free space in [0, skip_space - 1], 1428 * we must subtract it from the total. In order to implement 1429 * it, we account the used space in this range first. 1430 */ 1431 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1, 1432 &used_space); 1433 if (ret) { 1434 kfree(devices_info); 1435 return ret; 1436 } 1437 1438 /* calc the free space in [0, skip_space - 1] */ 1439 skip_space -= used_space; 1440 1441 /* 1442 * we can use the free space in [0, skip_space - 1], subtract 1443 * it from the total. 1444 */ 1445 if (avail_space && avail_space >= skip_space) 1446 avail_space -= skip_space; 1447 else 1448 avail_space = 0; 1449 1450 if (avail_space < min_stripe_size) 1451 continue; 1452 1453 devices_info[i].dev = device; 1454 devices_info[i].max_avail = avail_space; 1455 1456 i++; 1457 } 1458 1459 nr_devices = i; 1460 1461 btrfs_descending_sort_devices(devices_info, nr_devices); 1462 1463 i = nr_devices - 1; 1464 avail_space = 0; 1465 while (nr_devices >= min_stripes) { 1466 if (num_stripes > nr_devices) 1467 num_stripes = nr_devices; 1468 1469 if (devices_info[i].max_avail >= min_stripe_size) { 1470 int j; 1471 u64 alloc_size; 1472 1473 avail_space += devices_info[i].max_avail * num_stripes; 1474 alloc_size = devices_info[i].max_avail; 1475 for (j = i + 1 - num_stripes; j <= i; j++) 1476 devices_info[j].max_avail -= alloc_size; 1477 } 1478 i--; 1479 nr_devices--; 1480 } 1481 1482 kfree(devices_info); 1483 *free_bytes = avail_space; 1484 return 0; 1485 } 1486 1487 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 1488 { 1489 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb); 1490 struct btrfs_super_block *disk_super = fs_info->super_copy; 1491 struct list_head *head = &fs_info->space_info; 1492 struct btrfs_space_info *found; 1493 u64 total_used = 0; 1494 u64 total_free_data = 0; 1495 int bits = dentry->d_sb->s_blocksize_bits; 1496 __be32 *fsid = (__be32 *)fs_info->fsid; 1497 int ret; 1498 1499 /* holding chunk_muext to avoid allocating new chunks */ 1500 mutex_lock(&fs_info->chunk_mutex); 1501 rcu_read_lock(); 1502 list_for_each_entry_rcu(found, head, list) { 1503 if (found->flags & BTRFS_BLOCK_GROUP_DATA) { 1504 total_free_data += found->disk_total - found->disk_used; 1505 total_free_data -= 1506 btrfs_account_ro_block_groups_free_space(found); 1507 } 1508 1509 total_used += found->disk_used; 1510 } 1511 rcu_read_unlock(); 1512 1513 buf->f_namelen = BTRFS_NAME_LEN; 1514 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits; 1515 buf->f_bfree = buf->f_blocks - (total_used >> bits); 1516 buf->f_bsize = dentry->d_sb->s_blocksize; 1517 buf->f_type = BTRFS_SUPER_MAGIC; 1518 buf->f_bavail = total_free_data; 1519 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data); 1520 if (ret) { 1521 mutex_unlock(&fs_info->chunk_mutex); 1522 return ret; 1523 } 1524 buf->f_bavail += total_free_data; 1525 buf->f_bavail = buf->f_bavail >> bits; 1526 mutex_unlock(&fs_info->chunk_mutex); 1527 1528 /* We treat it as constant endianness (it doesn't matter _which_) 1529 because we want the fsid to come out the same whether mounted 1530 on a big-endian or little-endian host */ 1531 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]); 1532 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]); 1533 /* Mask in the root object ID too, to disambiguate subvols */ 1534 buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32; 1535 buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid; 1536 1537 return 0; 1538 } 1539 1540 static void btrfs_kill_super(struct super_block *sb) 1541 { 1542 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1543 kill_anon_super(sb); 1544 free_fs_info(fs_info); 1545 } 1546 1547 static struct file_system_type btrfs_fs_type = { 1548 .owner = THIS_MODULE, 1549 .name = "btrfs", 1550 .mount = btrfs_mount, 1551 .kill_sb = btrfs_kill_super, 1552 .fs_flags = FS_REQUIRES_DEV, 1553 }; 1554 MODULE_ALIAS_FS("btrfs"); 1555 1556 /* 1557 * used by btrfsctl to scan devices when no FS is mounted 1558 */ 1559 static long btrfs_control_ioctl(struct file *file, unsigned int cmd, 1560 unsigned long arg) 1561 { 1562 struct btrfs_ioctl_vol_args *vol; 1563 struct btrfs_fs_devices *fs_devices; 1564 int ret = -ENOTTY; 1565 1566 if (!capable(CAP_SYS_ADMIN)) 1567 return -EPERM; 1568 1569 vol = memdup_user((void __user *)arg, sizeof(*vol)); 1570 if (IS_ERR(vol)) 1571 return PTR_ERR(vol); 1572 1573 switch (cmd) { 1574 case BTRFS_IOC_SCAN_DEV: 1575 ret = btrfs_scan_one_device(vol->name, FMODE_READ, 1576 &btrfs_fs_type, &fs_devices); 1577 break; 1578 case BTRFS_IOC_DEVICES_READY: 1579 ret = btrfs_scan_one_device(vol->name, FMODE_READ, 1580 &btrfs_fs_type, &fs_devices); 1581 if (ret) 1582 break; 1583 ret = !(fs_devices->num_devices == fs_devices->total_devices); 1584 break; 1585 } 1586 1587 kfree(vol); 1588 return ret; 1589 } 1590 1591 static int btrfs_freeze(struct super_block *sb) 1592 { 1593 struct btrfs_trans_handle *trans; 1594 struct btrfs_root *root = btrfs_sb(sb)->tree_root; 1595 1596 trans = btrfs_attach_transaction_barrier(root); 1597 if (IS_ERR(trans)) { 1598 /* no transaction, don't bother */ 1599 if (PTR_ERR(trans) == -ENOENT) 1600 return 0; 1601 return PTR_ERR(trans); 1602 } 1603 return btrfs_commit_transaction(trans, root); 1604 } 1605 1606 static int btrfs_unfreeze(struct super_block *sb) 1607 { 1608 return 0; 1609 } 1610 1611 static int btrfs_show_devname(struct seq_file *m, struct dentry *root) 1612 { 1613 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb); 1614 struct btrfs_fs_devices *cur_devices; 1615 struct btrfs_device *dev, *first_dev = NULL; 1616 struct list_head *head; 1617 struct rcu_string *name; 1618 1619 mutex_lock(&fs_info->fs_devices->device_list_mutex); 1620 cur_devices = fs_info->fs_devices; 1621 while (cur_devices) { 1622 head = &cur_devices->devices; 1623 list_for_each_entry(dev, head, dev_list) { 1624 if (dev->missing) 1625 continue; 1626 if (!first_dev || dev->devid < first_dev->devid) 1627 first_dev = dev; 1628 } 1629 cur_devices = cur_devices->seed; 1630 } 1631 1632 if (first_dev) { 1633 rcu_read_lock(); 1634 name = rcu_dereference(first_dev->name); 1635 seq_escape(m, name->str, " \t\n\\"); 1636 rcu_read_unlock(); 1637 } else { 1638 WARN_ON(1); 1639 } 1640 mutex_unlock(&fs_info->fs_devices->device_list_mutex); 1641 return 0; 1642 } 1643 1644 static const struct super_operations btrfs_super_ops = { 1645 .drop_inode = btrfs_drop_inode, 1646 .evict_inode = btrfs_evict_inode, 1647 .put_super = btrfs_put_super, 1648 .sync_fs = btrfs_sync_fs, 1649 .show_options = btrfs_show_options, 1650 .show_devname = btrfs_show_devname, 1651 .write_inode = btrfs_write_inode, 1652 .alloc_inode = btrfs_alloc_inode, 1653 .destroy_inode = btrfs_destroy_inode, 1654 .statfs = btrfs_statfs, 1655 .remount_fs = btrfs_remount, 1656 .freeze_fs = btrfs_freeze, 1657 .unfreeze_fs = btrfs_unfreeze, 1658 }; 1659 1660 static const struct file_operations btrfs_ctl_fops = { 1661 .unlocked_ioctl = btrfs_control_ioctl, 1662 .compat_ioctl = btrfs_control_ioctl, 1663 .owner = THIS_MODULE, 1664 .llseek = noop_llseek, 1665 }; 1666 1667 static struct miscdevice btrfs_misc = { 1668 .minor = BTRFS_MINOR, 1669 .name = "btrfs-control", 1670 .fops = &btrfs_ctl_fops 1671 }; 1672 1673 MODULE_ALIAS_MISCDEV(BTRFS_MINOR); 1674 MODULE_ALIAS("devname:btrfs-control"); 1675 1676 static int btrfs_interface_init(void) 1677 { 1678 return misc_register(&btrfs_misc); 1679 } 1680 1681 static void btrfs_interface_exit(void) 1682 { 1683 if (misc_deregister(&btrfs_misc) < 0) 1684 printk(KERN_INFO "btrfs: misc_deregister failed for control device\n"); 1685 } 1686 1687 static void btrfs_print_info(void) 1688 { 1689 printk(KERN_INFO "Btrfs loaded" 1690 #ifdef CONFIG_BTRFS_DEBUG 1691 ", debug=on" 1692 #endif 1693 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY 1694 ", integrity-checker=on" 1695 #endif 1696 "\n"); 1697 } 1698 1699 static int __init init_btrfs_fs(void) 1700 { 1701 int err; 1702 1703 err = btrfs_init_sysfs(); 1704 if (err) 1705 return err; 1706 1707 btrfs_init_compress(); 1708 1709 err = btrfs_init_cachep(); 1710 if (err) 1711 goto free_compress; 1712 1713 err = extent_io_init(); 1714 if (err) 1715 goto free_cachep; 1716 1717 err = extent_map_init(); 1718 if (err) 1719 goto free_extent_io; 1720 1721 err = ordered_data_init(); 1722 if (err) 1723 goto free_extent_map; 1724 1725 err = btrfs_delayed_inode_init(); 1726 if (err) 1727 goto free_ordered_data; 1728 1729 err = btrfs_auto_defrag_init(); 1730 if (err) 1731 goto free_delayed_inode; 1732 1733 err = btrfs_delayed_ref_init(); 1734 if (err) 1735 goto free_auto_defrag; 1736 1737 err = btrfs_interface_init(); 1738 if (err) 1739 goto free_delayed_ref; 1740 1741 err = register_filesystem(&btrfs_fs_type); 1742 if (err) 1743 goto unregister_ioctl; 1744 1745 btrfs_init_lockdep(); 1746 1747 btrfs_print_info(); 1748 btrfs_test_free_space_cache(); 1749 1750 return 0; 1751 1752 unregister_ioctl: 1753 btrfs_interface_exit(); 1754 free_delayed_ref: 1755 btrfs_delayed_ref_exit(); 1756 free_auto_defrag: 1757 btrfs_auto_defrag_exit(); 1758 free_delayed_inode: 1759 btrfs_delayed_inode_exit(); 1760 free_ordered_data: 1761 ordered_data_exit(); 1762 free_extent_map: 1763 extent_map_exit(); 1764 free_extent_io: 1765 extent_io_exit(); 1766 free_cachep: 1767 btrfs_destroy_cachep(); 1768 free_compress: 1769 btrfs_exit_compress(); 1770 btrfs_exit_sysfs(); 1771 return err; 1772 } 1773 1774 static void __exit exit_btrfs_fs(void) 1775 { 1776 btrfs_destroy_cachep(); 1777 btrfs_delayed_ref_exit(); 1778 btrfs_auto_defrag_exit(); 1779 btrfs_delayed_inode_exit(); 1780 ordered_data_exit(); 1781 extent_map_exit(); 1782 extent_io_exit(); 1783 btrfs_interface_exit(); 1784 unregister_filesystem(&btrfs_fs_type); 1785 btrfs_exit_sysfs(); 1786 btrfs_cleanup_fs_uuids(); 1787 btrfs_exit_compress(); 1788 } 1789 1790 module_init(init_btrfs_fs) 1791 module_exit(exit_btrfs_fs) 1792 1793 MODULE_LICENSE("GPL"); 1794