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 "compat.h" 45 #include "delayed-inode.h" 46 #include "ctree.h" 47 #include "disk-io.h" 48 #include "transaction.h" 49 #include "btrfs_inode.h" 50 #include "ioctl.h" 51 #include "print-tree.h" 52 #include "xattr.h" 53 #include "volumes.h" 54 #include "version.h" 55 #include "export.h" 56 #include "compression.h" 57 #include "rcu-string.h" 58 59 #define CREATE_TRACE_POINTS 60 #include <trace/events/btrfs.h> 61 62 static const struct super_operations btrfs_super_ops; 63 static struct file_system_type btrfs_fs_type; 64 65 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno, 66 char nbuf[16]) 67 { 68 char *errstr = NULL; 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 default: 84 if (nbuf) { 85 if (snprintf(nbuf, 16, "error %d", -errno) >= 0) 86 errstr = nbuf; 87 } 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 fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR; 101 } 102 103 /* NOTE: 104 * We move write_super stuff at umount in order to avoid deadlock 105 * for umount hold all lock. 106 */ 107 static void save_error_info(struct btrfs_fs_info *fs_info) 108 { 109 __save_error_info(fs_info); 110 } 111 112 /* btrfs handle error by forcing the filesystem readonly */ 113 static void btrfs_handle_error(struct btrfs_fs_info *fs_info) 114 { 115 struct super_block *sb = fs_info->sb; 116 117 if (sb->s_flags & MS_RDONLY) 118 return; 119 120 if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) { 121 sb->s_flags |= MS_RDONLY; 122 printk(KERN_INFO "btrfs is forced readonly\n"); 123 __btrfs_scrub_cancel(fs_info); 124 // WARN_ON(1); 125 } 126 } 127 128 #ifdef CONFIG_PRINTK 129 /* 130 * __btrfs_std_error decodes expected errors from the caller and 131 * invokes the approciate error response. 132 */ 133 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, 134 unsigned int line, int errno, const char *fmt, ...) 135 { 136 struct super_block *sb = fs_info->sb; 137 char nbuf[16]; 138 const char *errstr; 139 va_list args; 140 va_start(args, fmt); 141 142 /* 143 * Special case: if the error is EROFS, and we're already 144 * under MS_RDONLY, then it is safe here. 145 */ 146 if (errno == -EROFS && (sb->s_flags & MS_RDONLY)) 147 return; 148 149 errstr = btrfs_decode_error(fs_info, errno, nbuf); 150 if (fmt) { 151 struct va_format vaf = { 152 .fmt = fmt, 153 .va = &args, 154 }; 155 156 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s (%pV)\n", 157 sb->s_id, function, line, errstr, &vaf); 158 } else { 159 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n", 160 sb->s_id, function, line, errstr); 161 } 162 163 /* Don't go through full error handling during mount */ 164 if (sb->s_flags & MS_BORN) { 165 save_error_info(fs_info); 166 btrfs_handle_error(fs_info); 167 } 168 va_end(args); 169 } 170 171 static const char * const logtypes[] = { 172 "emergency", 173 "alert", 174 "critical", 175 "error", 176 "warning", 177 "notice", 178 "info", 179 "debug", 180 }; 181 182 void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...) 183 { 184 struct super_block *sb = fs_info->sb; 185 char lvl[4]; 186 struct va_format vaf; 187 va_list args; 188 const char *type = logtypes[4]; 189 int kern_level; 190 191 va_start(args, fmt); 192 193 kern_level = printk_get_level(fmt); 194 if (kern_level) { 195 size_t size = printk_skip_level(fmt) - fmt; 196 memcpy(lvl, fmt, size); 197 lvl[size] = '\0'; 198 fmt += size; 199 type = logtypes[kern_level - '0']; 200 } else 201 *lvl = '\0'; 202 203 vaf.fmt = fmt; 204 vaf.va = &args; 205 206 printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf); 207 208 va_end(args); 209 } 210 211 #else 212 213 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, 214 unsigned int line, int errno, const char *fmt, ...) 215 { 216 struct super_block *sb = fs_info->sb; 217 218 /* 219 * Special case: if the error is EROFS, and we're already 220 * under MS_RDONLY, then it is safe here. 221 */ 222 if (errno == -EROFS && (sb->s_flags & MS_RDONLY)) 223 return; 224 225 /* Don't go through full error handling during mount */ 226 if (sb->s_flags & MS_BORN) { 227 save_error_info(fs_info); 228 btrfs_handle_error(fs_info); 229 } 230 } 231 #endif 232 233 /* 234 * We only mark the transaction aborted and then set the file system read-only. 235 * This will prevent new transactions from starting or trying to join this 236 * one. 237 * 238 * This means that error recovery at the call site is limited to freeing 239 * any local memory allocations and passing the error code up without 240 * further cleanup. The transaction should complete as it normally would 241 * in the call path but will return -EIO. 242 * 243 * We'll complete the cleanup in btrfs_end_transaction and 244 * btrfs_commit_transaction. 245 */ 246 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans, 247 struct btrfs_root *root, const char *function, 248 unsigned int line, int errno) 249 { 250 WARN_ONCE(1, KERN_DEBUG "btrfs: Transaction aborted"); 251 trans->aborted = errno; 252 /* Nothing used. The other threads that have joined this 253 * transaction may be able to continue. */ 254 if (!trans->blocks_used) { 255 btrfs_printk(root->fs_info, "Aborting unused transaction.\n"); 256 return; 257 } 258 trans->transaction->aborted = errno; 259 __btrfs_std_error(root->fs_info, function, line, errno, NULL); 260 } 261 /* 262 * __btrfs_panic decodes unexpected, fatal errors from the caller, 263 * issues an alert, and either panics or BUGs, depending on mount options. 264 */ 265 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function, 266 unsigned int line, int errno, const char *fmt, ...) 267 { 268 char nbuf[16]; 269 char *s_id = "<unknown>"; 270 const char *errstr; 271 struct va_format vaf = { .fmt = fmt }; 272 va_list args; 273 274 if (fs_info) 275 s_id = fs_info->sb->s_id; 276 277 va_start(args, fmt); 278 vaf.va = &args; 279 280 errstr = btrfs_decode_error(fs_info, errno, nbuf); 281 if (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR) 282 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n", 283 s_id, function, line, &vaf, errstr); 284 285 printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n", 286 s_id, function, line, &vaf, errstr); 287 va_end(args); 288 /* Caller calls BUG() */ 289 } 290 291 static void btrfs_put_super(struct super_block *sb) 292 { 293 (void)close_ctree(btrfs_sb(sb)->tree_root); 294 /* FIXME: need to fix VFS to return error? */ 295 /* AV: return it _where_? ->put_super() can be triggered by any number 296 * of async events, up to and including delivery of SIGKILL to the 297 * last process that kept it busy. Or segfault in the aforementioned 298 * process... Whom would you report that to? 299 */ 300 } 301 302 enum { 303 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum, 304 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, 305 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress, 306 Opt_compress_type, Opt_compress_force, Opt_compress_force_type, 307 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard, 308 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed, 309 Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache, 310 Opt_no_space_cache, Opt_recovery, Opt_skip_balance, 311 Opt_check_integrity, Opt_check_integrity_including_extent_data, 312 Opt_check_integrity_print_mask, Opt_fatal_errors, 313 Opt_err, 314 }; 315 316 static match_table_t tokens = { 317 {Opt_degraded, "degraded"}, 318 {Opt_subvol, "subvol=%s"}, 319 {Opt_subvolid, "subvolid=%d"}, 320 {Opt_device, "device=%s"}, 321 {Opt_nodatasum, "nodatasum"}, 322 {Opt_nodatacow, "nodatacow"}, 323 {Opt_nobarrier, "nobarrier"}, 324 {Opt_max_inline, "max_inline=%s"}, 325 {Opt_alloc_start, "alloc_start=%s"}, 326 {Opt_thread_pool, "thread_pool=%d"}, 327 {Opt_compress, "compress"}, 328 {Opt_compress_type, "compress=%s"}, 329 {Opt_compress_force, "compress-force"}, 330 {Opt_compress_force_type, "compress-force=%s"}, 331 {Opt_ssd, "ssd"}, 332 {Opt_ssd_spread, "ssd_spread"}, 333 {Opt_nossd, "nossd"}, 334 {Opt_noacl, "noacl"}, 335 {Opt_notreelog, "notreelog"}, 336 {Opt_flushoncommit, "flushoncommit"}, 337 {Opt_ratio, "metadata_ratio=%d"}, 338 {Opt_discard, "discard"}, 339 {Opt_space_cache, "space_cache"}, 340 {Opt_clear_cache, "clear_cache"}, 341 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"}, 342 {Opt_enospc_debug, "enospc_debug"}, 343 {Opt_subvolrootid, "subvolrootid=%d"}, 344 {Opt_defrag, "autodefrag"}, 345 {Opt_inode_cache, "inode_cache"}, 346 {Opt_no_space_cache, "nospace_cache"}, 347 {Opt_recovery, "recovery"}, 348 {Opt_skip_balance, "skip_balance"}, 349 {Opt_check_integrity, "check_int"}, 350 {Opt_check_integrity_including_extent_data, "check_int_data"}, 351 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"}, 352 {Opt_fatal_errors, "fatal_errors=%s"}, 353 {Opt_err, NULL}, 354 }; 355 356 /* 357 * Regular mount options parser. Everything that is needed only when 358 * reading in a new superblock is parsed here. 359 * XXX JDM: This needs to be cleaned up for remount. 360 */ 361 int btrfs_parse_options(struct btrfs_root *root, char *options) 362 { 363 struct btrfs_fs_info *info = root->fs_info; 364 substring_t args[MAX_OPT_ARGS]; 365 char *p, *num, *orig = NULL; 366 u64 cache_gen; 367 int intarg; 368 int ret = 0; 369 char *compress_type; 370 bool compress_force = false; 371 372 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy); 373 if (cache_gen) 374 btrfs_set_opt(info->mount_opt, SPACE_CACHE); 375 376 if (!options) 377 goto out; 378 379 /* 380 * strsep changes the string, duplicate it because parse_options 381 * gets called twice 382 */ 383 options = kstrdup(options, GFP_NOFS); 384 if (!options) 385 return -ENOMEM; 386 387 orig = options; 388 389 while ((p = strsep(&options, ",")) != NULL) { 390 int token; 391 if (!*p) 392 continue; 393 394 token = match_token(p, tokens, args); 395 switch (token) { 396 case Opt_degraded: 397 printk(KERN_INFO "btrfs: allowing degraded mounts\n"); 398 btrfs_set_opt(info->mount_opt, DEGRADED); 399 break; 400 case Opt_subvol: 401 case Opt_subvolid: 402 case Opt_subvolrootid: 403 case Opt_device: 404 /* 405 * These are parsed by btrfs_parse_early_options 406 * and can be happily ignored here. 407 */ 408 break; 409 case Opt_nodatasum: 410 printk(KERN_INFO "btrfs: setting nodatasum\n"); 411 btrfs_set_opt(info->mount_opt, NODATASUM); 412 break; 413 case Opt_nodatacow: 414 printk(KERN_INFO "btrfs: setting nodatacow\n"); 415 btrfs_set_opt(info->mount_opt, NODATACOW); 416 btrfs_set_opt(info->mount_opt, NODATASUM); 417 break; 418 case Opt_compress_force: 419 case Opt_compress_force_type: 420 compress_force = true; 421 case Opt_compress: 422 case Opt_compress_type: 423 if (token == Opt_compress || 424 token == Opt_compress_force || 425 strcmp(args[0].from, "zlib") == 0) { 426 compress_type = "zlib"; 427 info->compress_type = BTRFS_COMPRESS_ZLIB; 428 btrfs_set_opt(info->mount_opt, COMPRESS); 429 } else if (strcmp(args[0].from, "lzo") == 0) { 430 compress_type = "lzo"; 431 info->compress_type = BTRFS_COMPRESS_LZO; 432 btrfs_set_opt(info->mount_opt, COMPRESS); 433 btrfs_set_fs_incompat(info, COMPRESS_LZO); 434 } else if (strncmp(args[0].from, "no", 2) == 0) { 435 compress_type = "no"; 436 info->compress_type = BTRFS_COMPRESS_NONE; 437 btrfs_clear_opt(info->mount_opt, COMPRESS); 438 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS); 439 compress_force = false; 440 } else { 441 ret = -EINVAL; 442 goto out; 443 } 444 445 if (compress_force) { 446 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS); 447 pr_info("btrfs: force %s compression\n", 448 compress_type); 449 } else 450 pr_info("btrfs: use %s compression\n", 451 compress_type); 452 break; 453 case Opt_ssd: 454 printk(KERN_INFO "btrfs: use ssd allocation scheme\n"); 455 btrfs_set_opt(info->mount_opt, SSD); 456 break; 457 case Opt_ssd_spread: 458 printk(KERN_INFO "btrfs: use spread ssd " 459 "allocation scheme\n"); 460 btrfs_set_opt(info->mount_opt, SSD); 461 btrfs_set_opt(info->mount_opt, SSD_SPREAD); 462 break; 463 case Opt_nossd: 464 printk(KERN_INFO "btrfs: not using ssd allocation " 465 "scheme\n"); 466 btrfs_set_opt(info->mount_opt, NOSSD); 467 btrfs_clear_opt(info->mount_opt, SSD); 468 btrfs_clear_opt(info->mount_opt, SSD_SPREAD); 469 break; 470 case Opt_nobarrier: 471 printk(KERN_INFO "btrfs: turning off barriers\n"); 472 btrfs_set_opt(info->mount_opt, NOBARRIER); 473 break; 474 case Opt_thread_pool: 475 intarg = 0; 476 match_int(&args[0], &intarg); 477 if (intarg) 478 info->thread_pool_size = intarg; 479 break; 480 case Opt_max_inline: 481 num = match_strdup(&args[0]); 482 if (num) { 483 info->max_inline = memparse(num, NULL); 484 kfree(num); 485 486 if (info->max_inline) { 487 info->max_inline = max_t(u64, 488 info->max_inline, 489 root->sectorsize); 490 } 491 printk(KERN_INFO "btrfs: max_inline at %llu\n", 492 (unsigned long long)info->max_inline); 493 } 494 break; 495 case Opt_alloc_start: 496 num = match_strdup(&args[0]); 497 if (num) { 498 info->alloc_start = memparse(num, NULL); 499 kfree(num); 500 printk(KERN_INFO 501 "btrfs: allocations start at %llu\n", 502 (unsigned long long)info->alloc_start); 503 } 504 break; 505 case Opt_noacl: 506 root->fs_info->sb->s_flags &= ~MS_POSIXACL; 507 break; 508 case Opt_notreelog: 509 printk(KERN_INFO "btrfs: disabling tree log\n"); 510 btrfs_set_opt(info->mount_opt, NOTREELOG); 511 break; 512 case Opt_flushoncommit: 513 printk(KERN_INFO "btrfs: turning on flush-on-commit\n"); 514 btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT); 515 break; 516 case Opt_ratio: 517 intarg = 0; 518 match_int(&args[0], &intarg); 519 if (intarg) { 520 info->metadata_ratio = intarg; 521 printk(KERN_INFO "btrfs: metadata ratio %d\n", 522 info->metadata_ratio); 523 } 524 break; 525 case Opt_discard: 526 btrfs_set_opt(info->mount_opt, DISCARD); 527 break; 528 case Opt_space_cache: 529 btrfs_set_opt(info->mount_opt, SPACE_CACHE); 530 break; 531 case Opt_no_space_cache: 532 printk(KERN_INFO "btrfs: disabling disk space caching\n"); 533 btrfs_clear_opt(info->mount_opt, SPACE_CACHE); 534 break; 535 case Opt_inode_cache: 536 printk(KERN_INFO "btrfs: enabling inode map caching\n"); 537 btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE); 538 break; 539 case Opt_clear_cache: 540 printk(KERN_INFO "btrfs: force clearing of disk cache\n"); 541 btrfs_set_opt(info->mount_opt, CLEAR_CACHE); 542 break; 543 case Opt_user_subvol_rm_allowed: 544 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED); 545 break; 546 case Opt_enospc_debug: 547 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG); 548 break; 549 case Opt_defrag: 550 printk(KERN_INFO "btrfs: enabling auto defrag"); 551 btrfs_set_opt(info->mount_opt, AUTO_DEFRAG); 552 break; 553 case Opt_recovery: 554 printk(KERN_INFO "btrfs: enabling auto recovery"); 555 btrfs_set_opt(info->mount_opt, RECOVERY); 556 break; 557 case Opt_skip_balance: 558 btrfs_set_opt(info->mount_opt, SKIP_BALANCE); 559 break; 560 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY 561 case Opt_check_integrity_including_extent_data: 562 printk(KERN_INFO "btrfs: enabling check integrity" 563 " including extent data\n"); 564 btrfs_set_opt(info->mount_opt, 565 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA); 566 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY); 567 break; 568 case Opt_check_integrity: 569 printk(KERN_INFO "btrfs: enabling check integrity\n"); 570 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY); 571 break; 572 case Opt_check_integrity_print_mask: 573 intarg = 0; 574 match_int(&args[0], &intarg); 575 if (intarg) { 576 info->check_integrity_print_mask = intarg; 577 printk(KERN_INFO "btrfs:" 578 " check_integrity_print_mask 0x%x\n", 579 info->check_integrity_print_mask); 580 } 581 break; 582 #else 583 case Opt_check_integrity_including_extent_data: 584 case Opt_check_integrity: 585 case Opt_check_integrity_print_mask: 586 printk(KERN_ERR "btrfs: support for check_integrity*" 587 " not compiled in!\n"); 588 ret = -EINVAL; 589 goto out; 590 #endif 591 case Opt_fatal_errors: 592 if (strcmp(args[0].from, "panic") == 0) 593 btrfs_set_opt(info->mount_opt, 594 PANIC_ON_FATAL_ERROR); 595 else if (strcmp(args[0].from, "bug") == 0) 596 btrfs_clear_opt(info->mount_opt, 597 PANIC_ON_FATAL_ERROR); 598 else { 599 ret = -EINVAL; 600 goto out; 601 } 602 break; 603 case Opt_err: 604 printk(KERN_INFO "btrfs: unrecognized mount option " 605 "'%s'\n", p); 606 ret = -EINVAL; 607 goto out; 608 default: 609 break; 610 } 611 } 612 out: 613 if (!ret && btrfs_test_opt(root, SPACE_CACHE)) 614 printk(KERN_INFO "btrfs: disk space caching is enabled\n"); 615 kfree(orig); 616 return ret; 617 } 618 619 /* 620 * Parse mount options that are required early in the mount process. 621 * 622 * All other options will be parsed on much later in the mount process and 623 * only when we need to allocate a new super block. 624 */ 625 static int btrfs_parse_early_options(const char *options, fmode_t flags, 626 void *holder, char **subvol_name, u64 *subvol_objectid, 627 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices) 628 { 629 substring_t args[MAX_OPT_ARGS]; 630 char *device_name, *opts, *orig, *p; 631 int error = 0; 632 int intarg; 633 634 if (!options) 635 return 0; 636 637 /* 638 * strsep changes the string, duplicate it because parse_options 639 * gets called twice 640 */ 641 opts = kstrdup(options, GFP_KERNEL); 642 if (!opts) 643 return -ENOMEM; 644 orig = opts; 645 646 while ((p = strsep(&opts, ",")) != NULL) { 647 int token; 648 if (!*p) 649 continue; 650 651 token = match_token(p, tokens, args); 652 switch (token) { 653 case Opt_subvol: 654 kfree(*subvol_name); 655 *subvol_name = match_strdup(&args[0]); 656 break; 657 case Opt_subvolid: 658 intarg = 0; 659 error = match_int(&args[0], &intarg); 660 if (!error) { 661 /* we want the original fs_tree */ 662 if (!intarg) 663 *subvol_objectid = 664 BTRFS_FS_TREE_OBJECTID; 665 else 666 *subvol_objectid = intarg; 667 } 668 break; 669 case Opt_subvolrootid: 670 intarg = 0; 671 error = match_int(&args[0], &intarg); 672 if (!error) { 673 /* we want the original fs_tree */ 674 if (!intarg) 675 *subvol_rootid = 676 BTRFS_FS_TREE_OBJECTID; 677 else 678 *subvol_rootid = intarg; 679 } 680 break; 681 case Opt_device: 682 device_name = match_strdup(&args[0]); 683 if (!device_name) { 684 error = -ENOMEM; 685 goto out; 686 } 687 error = btrfs_scan_one_device(device_name, 688 flags, holder, fs_devices); 689 kfree(device_name); 690 if (error) 691 goto out; 692 break; 693 default: 694 break; 695 } 696 } 697 698 out: 699 kfree(orig); 700 return error; 701 } 702 703 static struct dentry *get_default_root(struct super_block *sb, 704 u64 subvol_objectid) 705 { 706 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 707 struct btrfs_root *root = fs_info->tree_root; 708 struct btrfs_root *new_root; 709 struct btrfs_dir_item *di; 710 struct btrfs_path *path; 711 struct btrfs_key location; 712 struct inode *inode; 713 u64 dir_id; 714 int new = 0; 715 716 /* 717 * We have a specific subvol we want to mount, just setup location and 718 * go look up the root. 719 */ 720 if (subvol_objectid) { 721 location.objectid = subvol_objectid; 722 location.type = BTRFS_ROOT_ITEM_KEY; 723 location.offset = (u64)-1; 724 goto find_root; 725 } 726 727 path = btrfs_alloc_path(); 728 if (!path) 729 return ERR_PTR(-ENOMEM); 730 path->leave_spinning = 1; 731 732 /* 733 * Find the "default" dir item which points to the root item that we 734 * will mount by default if we haven't been given a specific subvolume 735 * to mount. 736 */ 737 dir_id = btrfs_super_root_dir(fs_info->super_copy); 738 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0); 739 if (IS_ERR(di)) { 740 btrfs_free_path(path); 741 return ERR_CAST(di); 742 } 743 if (!di) { 744 /* 745 * Ok the default dir item isn't there. This is weird since 746 * it's always been there, but don't freak out, just try and 747 * mount to root most subvolume. 748 */ 749 btrfs_free_path(path); 750 dir_id = BTRFS_FIRST_FREE_OBJECTID; 751 new_root = fs_info->fs_root; 752 goto setup_root; 753 } 754 755 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); 756 btrfs_free_path(path); 757 758 find_root: 759 new_root = btrfs_read_fs_root_no_name(fs_info, &location); 760 if (IS_ERR(new_root)) 761 return ERR_CAST(new_root); 762 763 if (btrfs_root_refs(&new_root->root_item) == 0) 764 return ERR_PTR(-ENOENT); 765 766 dir_id = btrfs_root_dirid(&new_root->root_item); 767 setup_root: 768 location.objectid = dir_id; 769 location.type = BTRFS_INODE_ITEM_KEY; 770 location.offset = 0; 771 772 inode = btrfs_iget(sb, &location, new_root, &new); 773 if (IS_ERR(inode)) 774 return ERR_CAST(inode); 775 776 /* 777 * If we're just mounting the root most subvol put the inode and return 778 * a reference to the dentry. We will have already gotten a reference 779 * to the inode in btrfs_fill_super so we're good to go. 780 */ 781 if (!new && sb->s_root->d_inode == inode) { 782 iput(inode); 783 return dget(sb->s_root); 784 } 785 786 return d_obtain_alias(inode); 787 } 788 789 static int btrfs_fill_super(struct super_block *sb, 790 struct btrfs_fs_devices *fs_devices, 791 void *data, int silent) 792 { 793 struct inode *inode; 794 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 795 struct btrfs_key key; 796 int err; 797 798 sb->s_maxbytes = MAX_LFS_FILESIZE; 799 sb->s_magic = BTRFS_SUPER_MAGIC; 800 sb->s_op = &btrfs_super_ops; 801 sb->s_d_op = &btrfs_dentry_operations; 802 sb->s_export_op = &btrfs_export_ops; 803 sb->s_xattr = btrfs_xattr_handlers; 804 sb->s_time_gran = 1; 805 #ifdef CONFIG_BTRFS_FS_POSIX_ACL 806 sb->s_flags |= MS_POSIXACL; 807 #endif 808 sb->s_flags |= MS_I_VERSION; 809 err = open_ctree(sb, fs_devices, (char *)data); 810 if (err) { 811 printk("btrfs: open_ctree failed\n"); 812 return err; 813 } 814 815 key.objectid = BTRFS_FIRST_FREE_OBJECTID; 816 key.type = BTRFS_INODE_ITEM_KEY; 817 key.offset = 0; 818 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL); 819 if (IS_ERR(inode)) { 820 err = PTR_ERR(inode); 821 goto fail_close; 822 } 823 824 sb->s_root = d_make_root(inode); 825 if (!sb->s_root) { 826 err = -ENOMEM; 827 goto fail_close; 828 } 829 830 save_mount_options(sb, data); 831 cleancache_init_fs(sb); 832 sb->s_flags |= MS_ACTIVE; 833 return 0; 834 835 fail_close: 836 close_ctree(fs_info->tree_root); 837 return err; 838 } 839 840 int btrfs_sync_fs(struct super_block *sb, int wait) 841 { 842 struct btrfs_trans_handle *trans; 843 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 844 struct btrfs_root *root = fs_info->tree_root; 845 int ret; 846 847 trace_btrfs_sync_fs(wait); 848 849 if (!wait) { 850 filemap_flush(fs_info->btree_inode->i_mapping); 851 return 0; 852 } 853 854 btrfs_wait_ordered_extents(root, 0, 0); 855 856 trans = btrfs_start_transaction(root, 0); 857 if (IS_ERR(trans)) 858 return PTR_ERR(trans); 859 ret = btrfs_commit_transaction(trans, root); 860 return ret; 861 } 862 863 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) 864 { 865 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb); 866 struct btrfs_root *root = info->tree_root; 867 char *compress_type; 868 869 if (btrfs_test_opt(root, DEGRADED)) 870 seq_puts(seq, ",degraded"); 871 if (btrfs_test_opt(root, NODATASUM)) 872 seq_puts(seq, ",nodatasum"); 873 if (btrfs_test_opt(root, NODATACOW)) 874 seq_puts(seq, ",nodatacow"); 875 if (btrfs_test_opt(root, NOBARRIER)) 876 seq_puts(seq, ",nobarrier"); 877 if (info->max_inline != 8192 * 1024) 878 seq_printf(seq, ",max_inline=%llu", 879 (unsigned long long)info->max_inline); 880 if (info->alloc_start != 0) 881 seq_printf(seq, ",alloc_start=%llu", 882 (unsigned long long)info->alloc_start); 883 if (info->thread_pool_size != min_t(unsigned long, 884 num_online_cpus() + 2, 8)) 885 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size); 886 if (btrfs_test_opt(root, COMPRESS)) { 887 if (info->compress_type == BTRFS_COMPRESS_ZLIB) 888 compress_type = "zlib"; 889 else 890 compress_type = "lzo"; 891 if (btrfs_test_opt(root, FORCE_COMPRESS)) 892 seq_printf(seq, ",compress-force=%s", compress_type); 893 else 894 seq_printf(seq, ",compress=%s", compress_type); 895 } 896 if (btrfs_test_opt(root, NOSSD)) 897 seq_puts(seq, ",nossd"); 898 if (btrfs_test_opt(root, SSD_SPREAD)) 899 seq_puts(seq, ",ssd_spread"); 900 else if (btrfs_test_opt(root, SSD)) 901 seq_puts(seq, ",ssd"); 902 if (btrfs_test_opt(root, NOTREELOG)) 903 seq_puts(seq, ",notreelog"); 904 if (btrfs_test_opt(root, FLUSHONCOMMIT)) 905 seq_puts(seq, ",flushoncommit"); 906 if (btrfs_test_opt(root, DISCARD)) 907 seq_puts(seq, ",discard"); 908 if (!(root->fs_info->sb->s_flags & MS_POSIXACL)) 909 seq_puts(seq, ",noacl"); 910 if (btrfs_test_opt(root, SPACE_CACHE)) 911 seq_puts(seq, ",space_cache"); 912 else 913 seq_puts(seq, ",nospace_cache"); 914 if (btrfs_test_opt(root, CLEAR_CACHE)) 915 seq_puts(seq, ",clear_cache"); 916 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED)) 917 seq_puts(seq, ",user_subvol_rm_allowed"); 918 if (btrfs_test_opt(root, ENOSPC_DEBUG)) 919 seq_puts(seq, ",enospc_debug"); 920 if (btrfs_test_opt(root, AUTO_DEFRAG)) 921 seq_puts(seq, ",autodefrag"); 922 if (btrfs_test_opt(root, INODE_MAP_CACHE)) 923 seq_puts(seq, ",inode_cache"); 924 if (btrfs_test_opt(root, SKIP_BALANCE)) 925 seq_puts(seq, ",skip_balance"); 926 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR)) 927 seq_puts(seq, ",fatal_errors=panic"); 928 return 0; 929 } 930 931 static int btrfs_test_super(struct super_block *s, void *data) 932 { 933 struct btrfs_fs_info *p = data; 934 struct btrfs_fs_info *fs_info = btrfs_sb(s); 935 936 return fs_info->fs_devices == p->fs_devices; 937 } 938 939 static int btrfs_set_super(struct super_block *s, void *data) 940 { 941 int err = set_anon_super(s, data); 942 if (!err) 943 s->s_fs_info = data; 944 return err; 945 } 946 947 /* 948 * subvolumes are identified by ino 256 949 */ 950 static inline int is_subvolume_inode(struct inode *inode) 951 { 952 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) 953 return 1; 954 return 0; 955 } 956 957 /* 958 * This will strip out the subvol=%s argument for an argument string and add 959 * subvolid=0 to make sure we get the actual tree root for path walking to the 960 * subvol we want. 961 */ 962 static char *setup_root_args(char *args) 963 { 964 unsigned len = strlen(args) + 2 + 1; 965 char *src, *dst, *buf; 966 967 /* 968 * We need the same args as before, but with this substitution: 969 * s!subvol=[^,]+!subvolid=0! 970 * 971 * Since the replacement string is up to 2 bytes longer than the 972 * original, allocate strlen(args) + 2 + 1 bytes. 973 */ 974 975 src = strstr(args, "subvol="); 976 /* This shouldn't happen, but just in case.. */ 977 if (!src) 978 return NULL; 979 980 buf = dst = kmalloc(len, GFP_NOFS); 981 if (!buf) 982 return NULL; 983 984 /* 985 * If the subvol= arg is not at the start of the string, 986 * copy whatever precedes it into buf. 987 */ 988 if (src != args) { 989 *src++ = '\0'; 990 strcpy(buf, args); 991 dst += strlen(args); 992 } 993 994 strcpy(dst, "subvolid=0"); 995 dst += strlen("subvolid=0"); 996 997 /* 998 * If there is a "," after the original subvol=... string, 999 * copy that suffix into our buffer. Otherwise, we're done. 1000 */ 1001 src = strchr(src, ','); 1002 if (src) 1003 strcpy(dst, src); 1004 1005 return buf; 1006 } 1007 1008 static struct dentry *mount_subvol(const char *subvol_name, int flags, 1009 const char *device_name, char *data) 1010 { 1011 struct dentry *root; 1012 struct vfsmount *mnt; 1013 char *newargs; 1014 1015 newargs = setup_root_args(data); 1016 if (!newargs) 1017 return ERR_PTR(-ENOMEM); 1018 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, 1019 newargs); 1020 kfree(newargs); 1021 if (IS_ERR(mnt)) 1022 return ERR_CAST(mnt); 1023 1024 root = mount_subtree(mnt, subvol_name); 1025 1026 if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) { 1027 struct super_block *s = root->d_sb; 1028 dput(root); 1029 root = ERR_PTR(-EINVAL); 1030 deactivate_locked_super(s); 1031 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n", 1032 subvol_name); 1033 } 1034 1035 return root; 1036 } 1037 1038 /* 1039 * Find a superblock for the given device / mount point. 1040 * 1041 * Note: This is based on get_sb_bdev from fs/super.c with a few additions 1042 * for multiple device setup. Make sure to keep it in sync. 1043 */ 1044 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, 1045 const char *device_name, void *data) 1046 { 1047 struct block_device *bdev = NULL; 1048 struct super_block *s; 1049 struct dentry *root; 1050 struct btrfs_fs_devices *fs_devices = NULL; 1051 struct btrfs_fs_info *fs_info = NULL; 1052 fmode_t mode = FMODE_READ; 1053 char *subvol_name = NULL; 1054 u64 subvol_objectid = 0; 1055 u64 subvol_rootid = 0; 1056 int error = 0; 1057 1058 if (!(flags & MS_RDONLY)) 1059 mode |= FMODE_WRITE; 1060 1061 error = btrfs_parse_early_options(data, mode, fs_type, 1062 &subvol_name, &subvol_objectid, 1063 &subvol_rootid, &fs_devices); 1064 if (error) { 1065 kfree(subvol_name); 1066 return ERR_PTR(error); 1067 } 1068 1069 if (subvol_name) { 1070 root = mount_subvol(subvol_name, flags, device_name, data); 1071 kfree(subvol_name); 1072 return root; 1073 } 1074 1075 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices); 1076 if (error) 1077 return ERR_PTR(error); 1078 1079 /* 1080 * Setup a dummy root and fs_info for test/set super. This is because 1081 * we don't actually fill this stuff out until open_ctree, but we need 1082 * it for searching for existing supers, so this lets us do that and 1083 * then open_ctree will properly initialize everything later. 1084 */ 1085 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS); 1086 if (!fs_info) 1087 return ERR_PTR(-ENOMEM); 1088 1089 fs_info->fs_devices = fs_devices; 1090 1091 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS); 1092 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS); 1093 if (!fs_info->super_copy || !fs_info->super_for_commit) { 1094 error = -ENOMEM; 1095 goto error_fs_info; 1096 } 1097 1098 error = btrfs_open_devices(fs_devices, mode, fs_type); 1099 if (error) 1100 goto error_fs_info; 1101 1102 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) { 1103 error = -EACCES; 1104 goto error_close_devices; 1105 } 1106 1107 bdev = fs_devices->latest_bdev; 1108 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC, 1109 fs_info); 1110 if (IS_ERR(s)) { 1111 error = PTR_ERR(s); 1112 goto error_close_devices; 1113 } 1114 1115 if (s->s_root) { 1116 btrfs_close_devices(fs_devices); 1117 free_fs_info(fs_info); 1118 if ((flags ^ s->s_flags) & MS_RDONLY) 1119 error = -EBUSY; 1120 } else { 1121 char b[BDEVNAME_SIZE]; 1122 1123 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); 1124 btrfs_sb(s)->bdev_holder = fs_type; 1125 error = btrfs_fill_super(s, fs_devices, data, 1126 flags & MS_SILENT ? 1 : 0); 1127 } 1128 1129 root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error); 1130 if (IS_ERR(root)) 1131 deactivate_locked_super(s); 1132 1133 return root; 1134 1135 error_close_devices: 1136 btrfs_close_devices(fs_devices); 1137 error_fs_info: 1138 free_fs_info(fs_info); 1139 return ERR_PTR(error); 1140 } 1141 1142 static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit) 1143 { 1144 spin_lock_irq(&workers->lock); 1145 workers->max_workers = new_limit; 1146 spin_unlock_irq(&workers->lock); 1147 } 1148 1149 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info, 1150 int new_pool_size, int old_pool_size) 1151 { 1152 if (new_pool_size == old_pool_size) 1153 return; 1154 1155 fs_info->thread_pool_size = new_pool_size; 1156 1157 printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n", 1158 old_pool_size, new_pool_size); 1159 1160 btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size); 1161 btrfs_set_max_workers(&fs_info->workers, new_pool_size); 1162 btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size); 1163 btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size); 1164 btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size); 1165 btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size); 1166 btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size); 1167 btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size); 1168 btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size); 1169 btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size); 1170 btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size); 1171 btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size); 1172 btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size); 1173 btrfs_set_max_workers(&fs_info->scrub_workers, new_pool_size); 1174 } 1175 1176 static int btrfs_remount(struct super_block *sb, int *flags, char *data) 1177 { 1178 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1179 struct btrfs_root *root = fs_info->tree_root; 1180 unsigned old_flags = sb->s_flags; 1181 unsigned long old_opts = fs_info->mount_opt; 1182 unsigned long old_compress_type = fs_info->compress_type; 1183 u64 old_max_inline = fs_info->max_inline; 1184 u64 old_alloc_start = fs_info->alloc_start; 1185 int old_thread_pool_size = fs_info->thread_pool_size; 1186 unsigned int old_metadata_ratio = fs_info->metadata_ratio; 1187 int ret; 1188 1189 ret = btrfs_parse_options(root, data); 1190 if (ret) { 1191 ret = -EINVAL; 1192 goto restore; 1193 } 1194 1195 btrfs_resize_thread_pool(fs_info, 1196 fs_info->thread_pool_size, old_thread_pool_size); 1197 1198 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) 1199 return 0; 1200 1201 if (*flags & MS_RDONLY) { 1202 sb->s_flags |= MS_RDONLY; 1203 1204 ret = btrfs_commit_super(root); 1205 if (ret) 1206 goto restore; 1207 } else { 1208 if (fs_info->fs_devices->rw_devices == 0) { 1209 ret = -EACCES; 1210 goto restore; 1211 } 1212 1213 if (btrfs_super_log_root(fs_info->super_copy) != 0) { 1214 ret = -EINVAL; 1215 goto restore; 1216 } 1217 1218 ret = btrfs_cleanup_fs_roots(fs_info); 1219 if (ret) 1220 goto restore; 1221 1222 /* recover relocation */ 1223 ret = btrfs_recover_relocation(root); 1224 if (ret) 1225 goto restore; 1226 1227 ret = btrfs_resume_balance_async(fs_info); 1228 if (ret) 1229 goto restore; 1230 1231 sb->s_flags &= ~MS_RDONLY; 1232 } 1233 1234 return 0; 1235 1236 restore: 1237 /* We've hit an error - don't reset MS_RDONLY */ 1238 if (sb->s_flags & MS_RDONLY) 1239 old_flags |= MS_RDONLY; 1240 sb->s_flags = old_flags; 1241 fs_info->mount_opt = old_opts; 1242 fs_info->compress_type = old_compress_type; 1243 fs_info->max_inline = old_max_inline; 1244 fs_info->alloc_start = old_alloc_start; 1245 btrfs_resize_thread_pool(fs_info, 1246 old_thread_pool_size, fs_info->thread_pool_size); 1247 fs_info->metadata_ratio = old_metadata_ratio; 1248 return ret; 1249 } 1250 1251 /* Used to sort the devices by max_avail(descending sort) */ 1252 static int btrfs_cmp_device_free_bytes(const void *dev_info1, 1253 const void *dev_info2) 1254 { 1255 if (((struct btrfs_device_info *)dev_info1)->max_avail > 1256 ((struct btrfs_device_info *)dev_info2)->max_avail) 1257 return -1; 1258 else if (((struct btrfs_device_info *)dev_info1)->max_avail < 1259 ((struct btrfs_device_info *)dev_info2)->max_avail) 1260 return 1; 1261 else 1262 return 0; 1263 } 1264 1265 /* 1266 * sort the devices by max_avail, in which max free extent size of each device 1267 * is stored.(Descending Sort) 1268 */ 1269 static inline void btrfs_descending_sort_devices( 1270 struct btrfs_device_info *devices, 1271 size_t nr_devices) 1272 { 1273 sort(devices, nr_devices, sizeof(struct btrfs_device_info), 1274 btrfs_cmp_device_free_bytes, NULL); 1275 } 1276 1277 /* 1278 * The helper to calc the free space on the devices that can be used to store 1279 * file data. 1280 */ 1281 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) 1282 { 1283 struct btrfs_fs_info *fs_info = root->fs_info; 1284 struct btrfs_device_info *devices_info; 1285 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; 1286 struct btrfs_device *device; 1287 u64 skip_space; 1288 u64 type; 1289 u64 avail_space; 1290 u64 used_space; 1291 u64 min_stripe_size; 1292 int min_stripes = 1, num_stripes = 1; 1293 int i = 0, nr_devices; 1294 int ret; 1295 1296 nr_devices = fs_info->fs_devices->open_devices; 1297 BUG_ON(!nr_devices); 1298 1299 devices_info = kmalloc(sizeof(*devices_info) * nr_devices, 1300 GFP_NOFS); 1301 if (!devices_info) 1302 return -ENOMEM; 1303 1304 /* calc min stripe number for data space alloction */ 1305 type = btrfs_get_alloc_profile(root, 1); 1306 if (type & BTRFS_BLOCK_GROUP_RAID0) { 1307 min_stripes = 2; 1308 num_stripes = nr_devices; 1309 } else if (type & BTRFS_BLOCK_GROUP_RAID1) { 1310 min_stripes = 2; 1311 num_stripes = 2; 1312 } else if (type & BTRFS_BLOCK_GROUP_RAID10) { 1313 min_stripes = 4; 1314 num_stripes = 4; 1315 } 1316 1317 if (type & BTRFS_BLOCK_GROUP_DUP) 1318 min_stripe_size = 2 * BTRFS_STRIPE_LEN; 1319 else 1320 min_stripe_size = BTRFS_STRIPE_LEN; 1321 1322 list_for_each_entry(device, &fs_devices->devices, dev_list) { 1323 if (!device->in_fs_metadata || !device->bdev) 1324 continue; 1325 1326 avail_space = device->total_bytes - device->bytes_used; 1327 1328 /* align with stripe_len */ 1329 do_div(avail_space, BTRFS_STRIPE_LEN); 1330 avail_space *= BTRFS_STRIPE_LEN; 1331 1332 /* 1333 * In order to avoid overwritting the superblock on the drive, 1334 * btrfs starts at an offset of at least 1MB when doing chunk 1335 * allocation. 1336 */ 1337 skip_space = 1024 * 1024; 1338 1339 /* user can set the offset in fs_info->alloc_start. */ 1340 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <= 1341 device->total_bytes) 1342 skip_space = max(fs_info->alloc_start, skip_space); 1343 1344 /* 1345 * btrfs can not use the free space in [0, skip_space - 1], 1346 * we must subtract it from the total. In order to implement 1347 * it, we account the used space in this range first. 1348 */ 1349 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1, 1350 &used_space); 1351 if (ret) { 1352 kfree(devices_info); 1353 return ret; 1354 } 1355 1356 /* calc the free space in [0, skip_space - 1] */ 1357 skip_space -= used_space; 1358 1359 /* 1360 * we can use the free space in [0, skip_space - 1], subtract 1361 * it from the total. 1362 */ 1363 if (avail_space && avail_space >= skip_space) 1364 avail_space -= skip_space; 1365 else 1366 avail_space = 0; 1367 1368 if (avail_space < min_stripe_size) 1369 continue; 1370 1371 devices_info[i].dev = device; 1372 devices_info[i].max_avail = avail_space; 1373 1374 i++; 1375 } 1376 1377 nr_devices = i; 1378 1379 btrfs_descending_sort_devices(devices_info, nr_devices); 1380 1381 i = nr_devices - 1; 1382 avail_space = 0; 1383 while (nr_devices >= min_stripes) { 1384 if (num_stripes > nr_devices) 1385 num_stripes = nr_devices; 1386 1387 if (devices_info[i].max_avail >= min_stripe_size) { 1388 int j; 1389 u64 alloc_size; 1390 1391 avail_space += devices_info[i].max_avail * num_stripes; 1392 alloc_size = devices_info[i].max_avail; 1393 for (j = i + 1 - num_stripes; j <= i; j++) 1394 devices_info[j].max_avail -= alloc_size; 1395 } 1396 i--; 1397 nr_devices--; 1398 } 1399 1400 kfree(devices_info); 1401 *free_bytes = avail_space; 1402 return 0; 1403 } 1404 1405 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 1406 { 1407 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb); 1408 struct btrfs_super_block *disk_super = fs_info->super_copy; 1409 struct list_head *head = &fs_info->space_info; 1410 struct btrfs_space_info *found; 1411 u64 total_used = 0; 1412 u64 total_free_data = 0; 1413 int bits = dentry->d_sb->s_blocksize_bits; 1414 __be32 *fsid = (__be32 *)fs_info->fsid; 1415 int ret; 1416 1417 /* holding chunk_muext to avoid allocating new chunks */ 1418 mutex_lock(&fs_info->chunk_mutex); 1419 rcu_read_lock(); 1420 list_for_each_entry_rcu(found, head, list) { 1421 if (found->flags & BTRFS_BLOCK_GROUP_DATA) { 1422 total_free_data += found->disk_total - found->disk_used; 1423 total_free_data -= 1424 btrfs_account_ro_block_groups_free_space(found); 1425 } 1426 1427 total_used += found->disk_used; 1428 } 1429 rcu_read_unlock(); 1430 1431 buf->f_namelen = BTRFS_NAME_LEN; 1432 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits; 1433 buf->f_bfree = buf->f_blocks - (total_used >> bits); 1434 buf->f_bsize = dentry->d_sb->s_blocksize; 1435 buf->f_type = BTRFS_SUPER_MAGIC; 1436 buf->f_bavail = total_free_data; 1437 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data); 1438 if (ret) { 1439 mutex_unlock(&fs_info->chunk_mutex); 1440 return ret; 1441 } 1442 buf->f_bavail += total_free_data; 1443 buf->f_bavail = buf->f_bavail >> bits; 1444 mutex_unlock(&fs_info->chunk_mutex); 1445 1446 /* We treat it as constant endianness (it doesn't matter _which_) 1447 because we want the fsid to come out the same whether mounted 1448 on a big-endian or little-endian host */ 1449 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]); 1450 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]); 1451 /* Mask in the root object ID too, to disambiguate subvols */ 1452 buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32; 1453 buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid; 1454 1455 return 0; 1456 } 1457 1458 static void btrfs_kill_super(struct super_block *sb) 1459 { 1460 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1461 kill_anon_super(sb); 1462 free_fs_info(fs_info); 1463 } 1464 1465 static struct file_system_type btrfs_fs_type = { 1466 .owner = THIS_MODULE, 1467 .name = "btrfs", 1468 .mount = btrfs_mount, 1469 .kill_sb = btrfs_kill_super, 1470 .fs_flags = FS_REQUIRES_DEV, 1471 }; 1472 1473 /* 1474 * used by btrfsctl to scan devices when no FS is mounted 1475 */ 1476 static long btrfs_control_ioctl(struct file *file, unsigned int cmd, 1477 unsigned long arg) 1478 { 1479 struct btrfs_ioctl_vol_args *vol; 1480 struct btrfs_fs_devices *fs_devices; 1481 int ret = -ENOTTY; 1482 1483 if (!capable(CAP_SYS_ADMIN)) 1484 return -EPERM; 1485 1486 vol = memdup_user((void __user *)arg, sizeof(*vol)); 1487 if (IS_ERR(vol)) 1488 return PTR_ERR(vol); 1489 1490 switch (cmd) { 1491 case BTRFS_IOC_SCAN_DEV: 1492 ret = btrfs_scan_one_device(vol->name, FMODE_READ, 1493 &btrfs_fs_type, &fs_devices); 1494 break; 1495 case BTRFS_IOC_DEVICES_READY: 1496 ret = btrfs_scan_one_device(vol->name, FMODE_READ, 1497 &btrfs_fs_type, &fs_devices); 1498 if (ret) 1499 break; 1500 ret = !(fs_devices->num_devices == fs_devices->total_devices); 1501 break; 1502 } 1503 1504 kfree(vol); 1505 return ret; 1506 } 1507 1508 static int btrfs_freeze(struct super_block *sb) 1509 { 1510 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1511 mutex_lock(&fs_info->transaction_kthread_mutex); 1512 mutex_lock(&fs_info->cleaner_mutex); 1513 return 0; 1514 } 1515 1516 static int btrfs_unfreeze(struct super_block *sb) 1517 { 1518 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1519 mutex_unlock(&fs_info->cleaner_mutex); 1520 mutex_unlock(&fs_info->transaction_kthread_mutex); 1521 return 0; 1522 } 1523 1524 static int btrfs_show_devname(struct seq_file *m, struct dentry *root) 1525 { 1526 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb); 1527 struct btrfs_fs_devices *cur_devices; 1528 struct btrfs_device *dev, *first_dev = NULL; 1529 struct list_head *head; 1530 struct rcu_string *name; 1531 1532 mutex_lock(&fs_info->fs_devices->device_list_mutex); 1533 cur_devices = fs_info->fs_devices; 1534 while (cur_devices) { 1535 head = &cur_devices->devices; 1536 list_for_each_entry(dev, head, dev_list) { 1537 if (!first_dev || dev->devid < first_dev->devid) 1538 first_dev = dev; 1539 } 1540 cur_devices = cur_devices->seed; 1541 } 1542 1543 if (first_dev) { 1544 rcu_read_lock(); 1545 name = rcu_dereference(first_dev->name); 1546 seq_escape(m, name->str, " \t\n\\"); 1547 rcu_read_unlock(); 1548 } else { 1549 WARN_ON(1); 1550 } 1551 mutex_unlock(&fs_info->fs_devices->device_list_mutex); 1552 return 0; 1553 } 1554 1555 static const struct super_operations btrfs_super_ops = { 1556 .drop_inode = btrfs_drop_inode, 1557 .evict_inode = btrfs_evict_inode, 1558 .put_super = btrfs_put_super, 1559 .sync_fs = btrfs_sync_fs, 1560 .show_options = btrfs_show_options, 1561 .show_devname = btrfs_show_devname, 1562 .write_inode = btrfs_write_inode, 1563 .alloc_inode = btrfs_alloc_inode, 1564 .destroy_inode = btrfs_destroy_inode, 1565 .statfs = btrfs_statfs, 1566 .remount_fs = btrfs_remount, 1567 .freeze_fs = btrfs_freeze, 1568 .unfreeze_fs = btrfs_unfreeze, 1569 }; 1570 1571 static const struct file_operations btrfs_ctl_fops = { 1572 .unlocked_ioctl = btrfs_control_ioctl, 1573 .compat_ioctl = btrfs_control_ioctl, 1574 .owner = THIS_MODULE, 1575 .llseek = noop_llseek, 1576 }; 1577 1578 static struct miscdevice btrfs_misc = { 1579 .minor = BTRFS_MINOR, 1580 .name = "btrfs-control", 1581 .fops = &btrfs_ctl_fops 1582 }; 1583 1584 MODULE_ALIAS_MISCDEV(BTRFS_MINOR); 1585 MODULE_ALIAS("devname:btrfs-control"); 1586 1587 static int btrfs_interface_init(void) 1588 { 1589 return misc_register(&btrfs_misc); 1590 } 1591 1592 static void btrfs_interface_exit(void) 1593 { 1594 if (misc_deregister(&btrfs_misc) < 0) 1595 printk(KERN_INFO "misc_deregister failed for control device"); 1596 } 1597 1598 static int __init init_btrfs_fs(void) 1599 { 1600 int err; 1601 1602 err = btrfs_init_sysfs(); 1603 if (err) 1604 return err; 1605 1606 btrfs_init_compress(); 1607 1608 err = btrfs_init_cachep(); 1609 if (err) 1610 goto free_compress; 1611 1612 err = extent_io_init(); 1613 if (err) 1614 goto free_cachep; 1615 1616 err = extent_map_init(); 1617 if (err) 1618 goto free_extent_io; 1619 1620 err = btrfs_delayed_inode_init(); 1621 if (err) 1622 goto free_extent_map; 1623 1624 err = btrfs_interface_init(); 1625 if (err) 1626 goto free_delayed_inode; 1627 1628 err = register_filesystem(&btrfs_fs_type); 1629 if (err) 1630 goto unregister_ioctl; 1631 1632 btrfs_init_lockdep(); 1633 1634 printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION); 1635 return 0; 1636 1637 unregister_ioctl: 1638 btrfs_interface_exit(); 1639 free_delayed_inode: 1640 btrfs_delayed_inode_exit(); 1641 free_extent_map: 1642 extent_map_exit(); 1643 free_extent_io: 1644 extent_io_exit(); 1645 free_cachep: 1646 btrfs_destroy_cachep(); 1647 free_compress: 1648 btrfs_exit_compress(); 1649 btrfs_exit_sysfs(); 1650 return err; 1651 } 1652 1653 static void __exit exit_btrfs_fs(void) 1654 { 1655 btrfs_destroy_cachep(); 1656 btrfs_delayed_inode_exit(); 1657 extent_map_exit(); 1658 extent_io_exit(); 1659 btrfs_interface_exit(); 1660 unregister_filesystem(&btrfs_fs_type); 1661 btrfs_exit_sysfs(); 1662 btrfs_cleanup_fs_uuids(); 1663 btrfs_exit_compress(); 1664 } 1665 1666 module_init(init_btrfs_fs) 1667 module_exit(exit_btrfs_fs) 1668 1669 MODULE_LICENSE("GPL"); 1670