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 static void save_error_info(struct btrfs_fs_info *fs_info) 104 { 105 __save_error_info(fs_info); 106 } 107 108 /* btrfs handle error by forcing the filesystem readonly */ 109 static void btrfs_handle_error(struct btrfs_fs_info *fs_info) 110 { 111 struct super_block *sb = fs_info->sb; 112 113 if (sb->s_flags & MS_RDONLY) 114 return; 115 116 if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) { 117 sb->s_flags |= MS_RDONLY; 118 printk(KERN_INFO "btrfs is forced readonly\n"); 119 __btrfs_scrub_cancel(fs_info); 120 // WARN_ON(1); 121 } 122 } 123 124 #ifdef CONFIG_PRINTK 125 /* 126 * __btrfs_std_error decodes expected errors from the caller and 127 * invokes the approciate error response. 128 */ 129 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, 130 unsigned int line, int errno, const char *fmt, ...) 131 { 132 struct super_block *sb = fs_info->sb; 133 char nbuf[16]; 134 const char *errstr; 135 va_list args; 136 va_start(args, fmt); 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(fs_info, errno, nbuf); 146 if (fmt) { 147 struct va_format vaf = { 148 .fmt = fmt, 149 .va = &args, 150 }; 151 152 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s (%pV)\n", 153 sb->s_id, function, line, errstr, &vaf); 154 } else { 155 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n", 156 sb->s_id, function, line, errstr); 157 } 158 159 /* Don't go through full error handling during mount */ 160 if (sb->s_flags & MS_BORN) { 161 save_error_info(fs_info); 162 btrfs_handle_error(fs_info); 163 } 164 va_end(args); 165 } 166 167 static const char * const logtypes[] = { 168 "emergency", 169 "alert", 170 "critical", 171 "error", 172 "warning", 173 "notice", 174 "info", 175 "debug", 176 }; 177 178 void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...) 179 { 180 struct super_block *sb = fs_info->sb; 181 char lvl[4]; 182 struct va_format vaf; 183 va_list args; 184 const char *type = logtypes[4]; 185 int kern_level; 186 187 va_start(args, fmt); 188 189 kern_level = printk_get_level(fmt); 190 if (kern_level) { 191 size_t size = printk_skip_level(fmt) - fmt; 192 memcpy(lvl, fmt, size); 193 lvl[size] = '\0'; 194 fmt += size; 195 type = logtypes[kern_level - '0']; 196 } else 197 *lvl = '\0'; 198 199 vaf.fmt = fmt; 200 vaf.va = &args; 201 202 printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf); 203 204 va_end(args); 205 } 206 207 #else 208 209 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, 210 unsigned int line, int errno, const char *fmt, ...) 211 { 212 struct super_block *sb = fs_info->sb; 213 214 /* 215 * Special case: if the error is EROFS, and we're already 216 * under MS_RDONLY, then it is safe here. 217 */ 218 if (errno == -EROFS && (sb->s_flags & MS_RDONLY)) 219 return; 220 221 /* Don't go through full error handling during mount */ 222 if (sb->s_flags & MS_BORN) { 223 save_error_info(fs_info); 224 btrfs_handle_error(fs_info); 225 } 226 } 227 #endif 228 229 /* 230 * We only mark the transaction aborted and then set the file system read-only. 231 * This will prevent new transactions from starting or trying to join this 232 * one. 233 * 234 * This means that error recovery at the call site is limited to freeing 235 * any local memory allocations and passing the error code up without 236 * further cleanup. The transaction should complete as it normally would 237 * in the call path but will return -EIO. 238 * 239 * We'll complete the cleanup in btrfs_end_transaction and 240 * btrfs_commit_transaction. 241 */ 242 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans, 243 struct btrfs_root *root, const char *function, 244 unsigned int line, int errno) 245 { 246 WARN_ONCE(1, KERN_DEBUG "btrfs: Transaction aborted"); 247 trans->aborted = errno; 248 /* Nothing used. The other threads that have joined this 249 * transaction may be able to continue. */ 250 if (!trans->blocks_used) { 251 btrfs_printk(root->fs_info, "Aborting unused transaction.\n"); 252 return; 253 } 254 trans->transaction->aborted = errno; 255 __btrfs_std_error(root->fs_info, function, line, errno, NULL); 256 } 257 /* 258 * __btrfs_panic decodes unexpected, fatal errors from the caller, 259 * issues an alert, and either panics or BUGs, depending on mount options. 260 */ 261 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function, 262 unsigned int line, int errno, const char *fmt, ...) 263 { 264 char nbuf[16]; 265 char *s_id = "<unknown>"; 266 const char *errstr; 267 struct va_format vaf = { .fmt = fmt }; 268 va_list args; 269 270 if (fs_info) 271 s_id = fs_info->sb->s_id; 272 273 va_start(args, fmt); 274 vaf.va = &args; 275 276 errstr = btrfs_decode_error(fs_info, errno, nbuf); 277 if (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR) 278 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n", 279 s_id, function, line, &vaf, errstr); 280 281 printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n", 282 s_id, function, line, &vaf, errstr); 283 va_end(args); 284 /* Caller calls BUG() */ 285 } 286 287 static void btrfs_put_super(struct super_block *sb) 288 { 289 (void)close_ctree(btrfs_sb(sb)->tree_root); 290 /* FIXME: need to fix VFS to return error? */ 291 /* AV: return it _where_? ->put_super() can be triggered by any number 292 * of async events, up to and including delivery of SIGKILL to the 293 * last process that kept it busy. Or segfault in the aforementioned 294 * process... Whom would you report that to? 295 */ 296 } 297 298 enum { 299 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum, 300 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, 301 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress, 302 Opt_compress_type, Opt_compress_force, Opt_compress_force_type, 303 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard, 304 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed, 305 Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache, 306 Opt_no_space_cache, Opt_recovery, Opt_skip_balance, 307 Opt_check_integrity, Opt_check_integrity_including_extent_data, 308 Opt_check_integrity_print_mask, Opt_fatal_errors, 309 Opt_err, 310 }; 311 312 static match_table_t tokens = { 313 {Opt_degraded, "degraded"}, 314 {Opt_subvol, "subvol=%s"}, 315 {Opt_subvolid, "subvolid=%d"}, 316 {Opt_device, "device=%s"}, 317 {Opt_nodatasum, "nodatasum"}, 318 {Opt_nodatacow, "nodatacow"}, 319 {Opt_nobarrier, "nobarrier"}, 320 {Opt_max_inline, "max_inline=%s"}, 321 {Opt_alloc_start, "alloc_start=%s"}, 322 {Opt_thread_pool, "thread_pool=%d"}, 323 {Opt_compress, "compress"}, 324 {Opt_compress_type, "compress=%s"}, 325 {Opt_compress_force, "compress-force"}, 326 {Opt_compress_force_type, "compress-force=%s"}, 327 {Opt_ssd, "ssd"}, 328 {Opt_ssd_spread, "ssd_spread"}, 329 {Opt_nossd, "nossd"}, 330 {Opt_noacl, "noacl"}, 331 {Opt_notreelog, "notreelog"}, 332 {Opt_flushoncommit, "flushoncommit"}, 333 {Opt_ratio, "metadata_ratio=%d"}, 334 {Opt_discard, "discard"}, 335 {Opt_space_cache, "space_cache"}, 336 {Opt_clear_cache, "clear_cache"}, 337 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"}, 338 {Opt_enospc_debug, "enospc_debug"}, 339 {Opt_subvolrootid, "subvolrootid=%d"}, 340 {Opt_defrag, "autodefrag"}, 341 {Opt_inode_cache, "inode_cache"}, 342 {Opt_no_space_cache, "nospace_cache"}, 343 {Opt_recovery, "recovery"}, 344 {Opt_skip_balance, "skip_balance"}, 345 {Opt_check_integrity, "check_int"}, 346 {Opt_check_integrity_including_extent_data, "check_int_data"}, 347 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"}, 348 {Opt_fatal_errors, "fatal_errors=%s"}, 349 {Opt_err, NULL}, 350 }; 351 352 /* 353 * Regular mount options parser. Everything that is needed only when 354 * reading in a new superblock is parsed here. 355 * XXX JDM: This needs to be cleaned up for remount. 356 */ 357 int btrfs_parse_options(struct btrfs_root *root, char *options) 358 { 359 struct btrfs_fs_info *info = root->fs_info; 360 substring_t args[MAX_OPT_ARGS]; 361 char *p, *num, *orig = NULL; 362 u64 cache_gen; 363 int intarg; 364 int ret = 0; 365 char *compress_type; 366 bool compress_force = false; 367 368 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy); 369 if (cache_gen) 370 btrfs_set_opt(info->mount_opt, SPACE_CACHE); 371 372 if (!options) 373 goto out; 374 375 /* 376 * strsep changes the string, duplicate it because parse_options 377 * gets called twice 378 */ 379 options = kstrdup(options, GFP_NOFS); 380 if (!options) 381 return -ENOMEM; 382 383 orig = options; 384 385 while ((p = strsep(&options, ",")) != NULL) { 386 int token; 387 if (!*p) 388 continue; 389 390 token = match_token(p, tokens, args); 391 switch (token) { 392 case Opt_degraded: 393 printk(KERN_INFO "btrfs: allowing degraded mounts\n"); 394 btrfs_set_opt(info->mount_opt, DEGRADED); 395 break; 396 case Opt_subvol: 397 case Opt_subvolid: 398 case Opt_subvolrootid: 399 case Opt_device: 400 /* 401 * These are parsed by btrfs_parse_early_options 402 * and can be happily ignored here. 403 */ 404 break; 405 case Opt_nodatasum: 406 printk(KERN_INFO "btrfs: setting nodatasum\n"); 407 btrfs_set_opt(info->mount_opt, NODATASUM); 408 break; 409 case Opt_nodatacow: 410 printk(KERN_INFO "btrfs: setting nodatacow\n"); 411 btrfs_set_opt(info->mount_opt, NODATACOW); 412 btrfs_set_opt(info->mount_opt, NODATASUM); 413 break; 414 case Opt_compress_force: 415 case Opt_compress_force_type: 416 compress_force = true; 417 case Opt_compress: 418 case Opt_compress_type: 419 if (token == Opt_compress || 420 token == Opt_compress_force || 421 strcmp(args[0].from, "zlib") == 0) { 422 compress_type = "zlib"; 423 info->compress_type = BTRFS_COMPRESS_ZLIB; 424 btrfs_set_opt(info->mount_opt, COMPRESS); 425 } else if (strcmp(args[0].from, "lzo") == 0) { 426 compress_type = "lzo"; 427 info->compress_type = BTRFS_COMPRESS_LZO; 428 btrfs_set_opt(info->mount_opt, COMPRESS); 429 btrfs_set_fs_incompat(info, COMPRESS_LZO); 430 } else if (strncmp(args[0].from, "no", 2) == 0) { 431 compress_type = "no"; 432 info->compress_type = BTRFS_COMPRESS_NONE; 433 btrfs_clear_opt(info->mount_opt, COMPRESS); 434 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS); 435 compress_force = false; 436 } else { 437 ret = -EINVAL; 438 goto out; 439 } 440 441 if (compress_force) { 442 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS); 443 pr_info("btrfs: force %s compression\n", 444 compress_type); 445 } else 446 pr_info("btrfs: use %s compression\n", 447 compress_type); 448 break; 449 case Opt_ssd: 450 printk(KERN_INFO "btrfs: use ssd allocation scheme\n"); 451 btrfs_set_opt(info->mount_opt, SSD); 452 break; 453 case Opt_ssd_spread: 454 printk(KERN_INFO "btrfs: use spread ssd " 455 "allocation scheme\n"); 456 btrfs_set_opt(info->mount_opt, SSD); 457 btrfs_set_opt(info->mount_opt, SSD_SPREAD); 458 break; 459 case Opt_nossd: 460 printk(KERN_INFO "btrfs: not using ssd allocation " 461 "scheme\n"); 462 btrfs_set_opt(info->mount_opt, NOSSD); 463 btrfs_clear_opt(info->mount_opt, SSD); 464 btrfs_clear_opt(info->mount_opt, SSD_SPREAD); 465 break; 466 case Opt_nobarrier: 467 printk(KERN_INFO "btrfs: turning off barriers\n"); 468 btrfs_set_opt(info->mount_opt, NOBARRIER); 469 break; 470 case Opt_thread_pool: 471 intarg = 0; 472 match_int(&args[0], &intarg); 473 if (intarg) 474 info->thread_pool_size = intarg; 475 break; 476 case Opt_max_inline: 477 num = match_strdup(&args[0]); 478 if (num) { 479 info->max_inline = memparse(num, NULL); 480 kfree(num); 481 482 if (info->max_inline) { 483 info->max_inline = max_t(u64, 484 info->max_inline, 485 root->sectorsize); 486 } 487 printk(KERN_INFO "btrfs: max_inline at %llu\n", 488 (unsigned long long)info->max_inline); 489 } 490 break; 491 case Opt_alloc_start: 492 num = match_strdup(&args[0]); 493 if (num) { 494 info->alloc_start = memparse(num, NULL); 495 kfree(num); 496 printk(KERN_INFO 497 "btrfs: allocations start at %llu\n", 498 (unsigned long long)info->alloc_start); 499 } 500 break; 501 case Opt_noacl: 502 root->fs_info->sb->s_flags &= ~MS_POSIXACL; 503 break; 504 case Opt_notreelog: 505 printk(KERN_INFO "btrfs: disabling tree log\n"); 506 btrfs_set_opt(info->mount_opt, NOTREELOG); 507 break; 508 case Opt_flushoncommit: 509 printk(KERN_INFO "btrfs: turning on flush-on-commit\n"); 510 btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT); 511 break; 512 case Opt_ratio: 513 intarg = 0; 514 match_int(&args[0], &intarg); 515 if (intarg) { 516 info->metadata_ratio = intarg; 517 printk(KERN_INFO "btrfs: metadata ratio %d\n", 518 info->metadata_ratio); 519 } 520 break; 521 case Opt_discard: 522 btrfs_set_opt(info->mount_opt, DISCARD); 523 break; 524 case Opt_space_cache: 525 btrfs_set_opt(info->mount_opt, SPACE_CACHE); 526 break; 527 case Opt_no_space_cache: 528 printk(KERN_INFO "btrfs: disabling disk space caching\n"); 529 btrfs_clear_opt(info->mount_opt, SPACE_CACHE); 530 break; 531 case Opt_inode_cache: 532 printk(KERN_INFO "btrfs: enabling inode map caching\n"); 533 btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE); 534 break; 535 case Opt_clear_cache: 536 printk(KERN_INFO "btrfs: force clearing of disk cache\n"); 537 btrfs_set_opt(info->mount_opt, CLEAR_CACHE); 538 break; 539 case Opt_user_subvol_rm_allowed: 540 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED); 541 break; 542 case Opt_enospc_debug: 543 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG); 544 break; 545 case Opt_defrag: 546 printk(KERN_INFO "btrfs: enabling auto defrag"); 547 btrfs_set_opt(info->mount_opt, AUTO_DEFRAG); 548 break; 549 case Opt_recovery: 550 printk(KERN_INFO "btrfs: enabling auto recovery"); 551 btrfs_set_opt(info->mount_opt, RECOVERY); 552 break; 553 case Opt_skip_balance: 554 btrfs_set_opt(info->mount_opt, SKIP_BALANCE); 555 break; 556 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY 557 case Opt_check_integrity_including_extent_data: 558 printk(KERN_INFO "btrfs: enabling check integrity" 559 " including extent data\n"); 560 btrfs_set_opt(info->mount_opt, 561 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA); 562 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY); 563 break; 564 case Opt_check_integrity: 565 printk(KERN_INFO "btrfs: enabling check integrity\n"); 566 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY); 567 break; 568 case Opt_check_integrity_print_mask: 569 intarg = 0; 570 match_int(&args[0], &intarg); 571 if (intarg) { 572 info->check_integrity_print_mask = intarg; 573 printk(KERN_INFO "btrfs:" 574 " check_integrity_print_mask 0x%x\n", 575 info->check_integrity_print_mask); 576 } 577 break; 578 #else 579 case Opt_check_integrity_including_extent_data: 580 case Opt_check_integrity: 581 case Opt_check_integrity_print_mask: 582 printk(KERN_ERR "btrfs: support for check_integrity*" 583 " not compiled in!\n"); 584 ret = -EINVAL; 585 goto out; 586 #endif 587 case Opt_fatal_errors: 588 if (strcmp(args[0].from, "panic") == 0) 589 btrfs_set_opt(info->mount_opt, 590 PANIC_ON_FATAL_ERROR); 591 else if (strcmp(args[0].from, "bug") == 0) 592 btrfs_clear_opt(info->mount_opt, 593 PANIC_ON_FATAL_ERROR); 594 else { 595 ret = -EINVAL; 596 goto out; 597 } 598 break; 599 case Opt_err: 600 printk(KERN_INFO "btrfs: unrecognized mount option " 601 "'%s'\n", p); 602 ret = -EINVAL; 603 goto out; 604 default: 605 break; 606 } 607 } 608 out: 609 if (!ret && btrfs_test_opt(root, SPACE_CACHE)) 610 printk(KERN_INFO "btrfs: disk space caching is enabled\n"); 611 kfree(orig); 612 return ret; 613 } 614 615 /* 616 * Parse mount options that are required early in the mount process. 617 * 618 * All other options will be parsed on much later in the mount process and 619 * only when we need to allocate a new super block. 620 */ 621 static int btrfs_parse_early_options(const char *options, fmode_t flags, 622 void *holder, char **subvol_name, u64 *subvol_objectid, 623 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices) 624 { 625 substring_t args[MAX_OPT_ARGS]; 626 char *device_name, *opts, *orig, *p; 627 int error = 0; 628 int intarg; 629 630 if (!options) 631 return 0; 632 633 /* 634 * strsep changes the string, duplicate it because parse_options 635 * gets called twice 636 */ 637 opts = kstrdup(options, GFP_KERNEL); 638 if (!opts) 639 return -ENOMEM; 640 orig = opts; 641 642 while ((p = strsep(&opts, ",")) != NULL) { 643 int token; 644 if (!*p) 645 continue; 646 647 token = match_token(p, tokens, args); 648 switch (token) { 649 case Opt_subvol: 650 kfree(*subvol_name); 651 *subvol_name = match_strdup(&args[0]); 652 break; 653 case Opt_subvolid: 654 intarg = 0; 655 error = match_int(&args[0], &intarg); 656 if (!error) { 657 /* we want the original fs_tree */ 658 if (!intarg) 659 *subvol_objectid = 660 BTRFS_FS_TREE_OBJECTID; 661 else 662 *subvol_objectid = intarg; 663 } 664 break; 665 case Opt_subvolrootid: 666 intarg = 0; 667 error = match_int(&args[0], &intarg); 668 if (!error) { 669 /* we want the original fs_tree */ 670 if (!intarg) 671 *subvol_rootid = 672 BTRFS_FS_TREE_OBJECTID; 673 else 674 *subvol_rootid = intarg; 675 } 676 break; 677 case Opt_device: 678 device_name = match_strdup(&args[0]); 679 if (!device_name) { 680 error = -ENOMEM; 681 goto out; 682 } 683 error = btrfs_scan_one_device(device_name, 684 flags, holder, fs_devices); 685 kfree(device_name); 686 if (error) 687 goto out; 688 break; 689 default: 690 break; 691 } 692 } 693 694 out: 695 kfree(orig); 696 return error; 697 } 698 699 static struct dentry *get_default_root(struct super_block *sb, 700 u64 subvol_objectid) 701 { 702 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 703 struct btrfs_root *root = fs_info->tree_root; 704 struct btrfs_root *new_root; 705 struct btrfs_dir_item *di; 706 struct btrfs_path *path; 707 struct btrfs_key location; 708 struct inode *inode; 709 u64 dir_id; 710 int new = 0; 711 712 /* 713 * We have a specific subvol we want to mount, just setup location and 714 * go look up the root. 715 */ 716 if (subvol_objectid) { 717 location.objectid = subvol_objectid; 718 location.type = BTRFS_ROOT_ITEM_KEY; 719 location.offset = (u64)-1; 720 goto find_root; 721 } 722 723 path = btrfs_alloc_path(); 724 if (!path) 725 return ERR_PTR(-ENOMEM); 726 path->leave_spinning = 1; 727 728 /* 729 * Find the "default" dir item which points to the root item that we 730 * will mount by default if we haven't been given a specific subvolume 731 * to mount. 732 */ 733 dir_id = btrfs_super_root_dir(fs_info->super_copy); 734 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0); 735 if (IS_ERR(di)) { 736 btrfs_free_path(path); 737 return ERR_CAST(di); 738 } 739 if (!di) { 740 /* 741 * Ok the default dir item isn't there. This is weird since 742 * it's always been there, but don't freak out, just try and 743 * mount to root most subvolume. 744 */ 745 btrfs_free_path(path); 746 dir_id = BTRFS_FIRST_FREE_OBJECTID; 747 new_root = fs_info->fs_root; 748 goto setup_root; 749 } 750 751 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); 752 btrfs_free_path(path); 753 754 find_root: 755 new_root = btrfs_read_fs_root_no_name(fs_info, &location); 756 if (IS_ERR(new_root)) 757 return ERR_CAST(new_root); 758 759 if (btrfs_root_refs(&new_root->root_item) == 0) 760 return ERR_PTR(-ENOENT); 761 762 dir_id = btrfs_root_dirid(&new_root->root_item); 763 setup_root: 764 location.objectid = dir_id; 765 location.type = BTRFS_INODE_ITEM_KEY; 766 location.offset = 0; 767 768 inode = btrfs_iget(sb, &location, new_root, &new); 769 if (IS_ERR(inode)) 770 return ERR_CAST(inode); 771 772 /* 773 * If we're just mounting the root most subvol put the inode and return 774 * a reference to the dentry. We will have already gotten a reference 775 * to the inode in btrfs_fill_super so we're good to go. 776 */ 777 if (!new && sb->s_root->d_inode == inode) { 778 iput(inode); 779 return dget(sb->s_root); 780 } 781 782 return d_obtain_alias(inode); 783 } 784 785 static int btrfs_fill_super(struct super_block *sb, 786 struct btrfs_fs_devices *fs_devices, 787 void *data, int silent) 788 { 789 struct inode *inode; 790 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 791 struct btrfs_key key; 792 int err; 793 794 sb->s_maxbytes = MAX_LFS_FILESIZE; 795 sb->s_magic = BTRFS_SUPER_MAGIC; 796 sb->s_op = &btrfs_super_ops; 797 sb->s_d_op = &btrfs_dentry_operations; 798 sb->s_export_op = &btrfs_export_ops; 799 sb->s_xattr = btrfs_xattr_handlers; 800 sb->s_time_gran = 1; 801 #ifdef CONFIG_BTRFS_FS_POSIX_ACL 802 sb->s_flags |= MS_POSIXACL; 803 #endif 804 sb->s_flags |= MS_I_VERSION; 805 err = open_ctree(sb, fs_devices, (char *)data); 806 if (err) { 807 printk("btrfs: open_ctree failed\n"); 808 return err; 809 } 810 811 key.objectid = BTRFS_FIRST_FREE_OBJECTID; 812 key.type = BTRFS_INODE_ITEM_KEY; 813 key.offset = 0; 814 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL); 815 if (IS_ERR(inode)) { 816 err = PTR_ERR(inode); 817 goto fail_close; 818 } 819 820 sb->s_root = d_make_root(inode); 821 if (!sb->s_root) { 822 err = -ENOMEM; 823 goto fail_close; 824 } 825 826 save_mount_options(sb, data); 827 cleancache_init_fs(sb); 828 sb->s_flags |= MS_ACTIVE; 829 return 0; 830 831 fail_close: 832 close_ctree(fs_info->tree_root); 833 return err; 834 } 835 836 int btrfs_sync_fs(struct super_block *sb, int wait) 837 { 838 struct btrfs_trans_handle *trans; 839 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 840 struct btrfs_root *root = fs_info->tree_root; 841 842 trace_btrfs_sync_fs(wait); 843 844 if (!wait) { 845 filemap_flush(fs_info->btree_inode->i_mapping); 846 return 0; 847 } 848 849 btrfs_wait_ordered_extents(root, 0, 0); 850 851 spin_lock(&fs_info->trans_lock); 852 if (!fs_info->running_transaction) { 853 spin_unlock(&fs_info->trans_lock); 854 return 0; 855 } 856 spin_unlock(&fs_info->trans_lock); 857 858 trans = btrfs_join_transaction(root); 859 if (IS_ERR(trans)) 860 return PTR_ERR(trans); 861 return btrfs_commit_transaction(trans, root); 862 } 863 864 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) 865 { 866 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb); 867 struct btrfs_root *root = info->tree_root; 868 char *compress_type; 869 870 if (btrfs_test_opt(root, DEGRADED)) 871 seq_puts(seq, ",degraded"); 872 if (btrfs_test_opt(root, NODATASUM)) 873 seq_puts(seq, ",nodatasum"); 874 if (btrfs_test_opt(root, NODATACOW)) 875 seq_puts(seq, ",nodatacow"); 876 if (btrfs_test_opt(root, NOBARRIER)) 877 seq_puts(seq, ",nobarrier"); 878 if (info->max_inline != 8192 * 1024) 879 seq_printf(seq, ",max_inline=%llu", 880 (unsigned long long)info->max_inline); 881 if (info->alloc_start != 0) 882 seq_printf(seq, ",alloc_start=%llu", 883 (unsigned long long)info->alloc_start); 884 if (info->thread_pool_size != min_t(unsigned long, 885 num_online_cpus() + 2, 8)) 886 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size); 887 if (btrfs_test_opt(root, COMPRESS)) { 888 if (info->compress_type == BTRFS_COMPRESS_ZLIB) 889 compress_type = "zlib"; 890 else 891 compress_type = "lzo"; 892 if (btrfs_test_opt(root, FORCE_COMPRESS)) 893 seq_printf(seq, ",compress-force=%s", compress_type); 894 else 895 seq_printf(seq, ",compress=%s", compress_type); 896 } 897 if (btrfs_test_opt(root, NOSSD)) 898 seq_puts(seq, ",nossd"); 899 if (btrfs_test_opt(root, SSD_SPREAD)) 900 seq_puts(seq, ",ssd_spread"); 901 else if (btrfs_test_opt(root, SSD)) 902 seq_puts(seq, ",ssd"); 903 if (btrfs_test_opt(root, NOTREELOG)) 904 seq_puts(seq, ",notreelog"); 905 if (btrfs_test_opt(root, FLUSHONCOMMIT)) 906 seq_puts(seq, ",flushoncommit"); 907 if (btrfs_test_opt(root, DISCARD)) 908 seq_puts(seq, ",discard"); 909 if (!(root->fs_info->sb->s_flags & MS_POSIXACL)) 910 seq_puts(seq, ",noacl"); 911 if (btrfs_test_opt(root, SPACE_CACHE)) 912 seq_puts(seq, ",space_cache"); 913 else 914 seq_puts(seq, ",nospace_cache"); 915 if (btrfs_test_opt(root, CLEAR_CACHE)) 916 seq_puts(seq, ",clear_cache"); 917 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED)) 918 seq_puts(seq, ",user_subvol_rm_allowed"); 919 if (btrfs_test_opt(root, ENOSPC_DEBUG)) 920 seq_puts(seq, ",enospc_debug"); 921 if (btrfs_test_opt(root, AUTO_DEFRAG)) 922 seq_puts(seq, ",autodefrag"); 923 if (btrfs_test_opt(root, INODE_MAP_CACHE)) 924 seq_puts(seq, ",inode_cache"); 925 if (btrfs_test_opt(root, SKIP_BALANCE)) 926 seq_puts(seq, ",skip_balance"); 927 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR)) 928 seq_puts(seq, ",fatal_errors=panic"); 929 return 0; 930 } 931 932 static int btrfs_test_super(struct super_block *s, void *data) 933 { 934 struct btrfs_fs_info *p = data; 935 struct btrfs_fs_info *fs_info = btrfs_sb(s); 936 937 return fs_info->fs_devices == p->fs_devices; 938 } 939 940 static int btrfs_set_super(struct super_block *s, void *data) 941 { 942 int err = set_anon_super(s, data); 943 if (!err) 944 s->s_fs_info = data; 945 return err; 946 } 947 948 /* 949 * subvolumes are identified by ino 256 950 */ 951 static inline int is_subvolume_inode(struct inode *inode) 952 { 953 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) 954 return 1; 955 return 0; 956 } 957 958 /* 959 * This will strip out the subvol=%s argument for an argument string and add 960 * subvolid=0 to make sure we get the actual tree root for path walking to the 961 * subvol we want. 962 */ 963 static char *setup_root_args(char *args) 964 { 965 unsigned len = strlen(args) + 2 + 1; 966 char *src, *dst, *buf; 967 968 /* 969 * We need the same args as before, but with this substitution: 970 * s!subvol=[^,]+!subvolid=0! 971 * 972 * Since the replacement string is up to 2 bytes longer than the 973 * original, allocate strlen(args) + 2 + 1 bytes. 974 */ 975 976 src = strstr(args, "subvol="); 977 /* This shouldn't happen, but just in case.. */ 978 if (!src) 979 return NULL; 980 981 buf = dst = kmalloc(len, GFP_NOFS); 982 if (!buf) 983 return NULL; 984 985 /* 986 * If the subvol= arg is not at the start of the string, 987 * copy whatever precedes it into buf. 988 */ 989 if (src != args) { 990 *src++ = '\0'; 991 strcpy(buf, args); 992 dst += strlen(args); 993 } 994 995 strcpy(dst, "subvolid=0"); 996 dst += strlen("subvolid=0"); 997 998 /* 999 * If there is a "," after the original subvol=... string, 1000 * copy that suffix into our buffer. Otherwise, we're done. 1001 */ 1002 src = strchr(src, ','); 1003 if (src) 1004 strcpy(dst, src); 1005 1006 return buf; 1007 } 1008 1009 static struct dentry *mount_subvol(const char *subvol_name, int flags, 1010 const char *device_name, char *data) 1011 { 1012 struct dentry *root; 1013 struct vfsmount *mnt; 1014 char *newargs; 1015 1016 newargs = setup_root_args(data); 1017 if (!newargs) 1018 return ERR_PTR(-ENOMEM); 1019 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, 1020 newargs); 1021 kfree(newargs); 1022 if (IS_ERR(mnt)) 1023 return ERR_CAST(mnt); 1024 1025 root = mount_subtree(mnt, subvol_name); 1026 1027 if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) { 1028 struct super_block *s = root->d_sb; 1029 dput(root); 1030 root = ERR_PTR(-EINVAL); 1031 deactivate_locked_super(s); 1032 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n", 1033 subvol_name); 1034 } 1035 1036 return root; 1037 } 1038 1039 /* 1040 * Find a superblock for the given device / mount point. 1041 * 1042 * Note: This is based on get_sb_bdev from fs/super.c with a few additions 1043 * for multiple device setup. Make sure to keep it in sync. 1044 */ 1045 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, 1046 const char *device_name, void *data) 1047 { 1048 struct block_device *bdev = NULL; 1049 struct super_block *s; 1050 struct dentry *root; 1051 struct btrfs_fs_devices *fs_devices = NULL; 1052 struct btrfs_fs_info *fs_info = NULL; 1053 fmode_t mode = FMODE_READ; 1054 char *subvol_name = NULL; 1055 u64 subvol_objectid = 0; 1056 u64 subvol_rootid = 0; 1057 int error = 0; 1058 1059 if (!(flags & MS_RDONLY)) 1060 mode |= FMODE_WRITE; 1061 1062 error = btrfs_parse_early_options(data, mode, fs_type, 1063 &subvol_name, &subvol_objectid, 1064 &subvol_rootid, &fs_devices); 1065 if (error) { 1066 kfree(subvol_name); 1067 return ERR_PTR(error); 1068 } 1069 1070 if (subvol_name) { 1071 root = mount_subvol(subvol_name, flags, device_name, data); 1072 kfree(subvol_name); 1073 return root; 1074 } 1075 1076 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices); 1077 if (error) 1078 return ERR_PTR(error); 1079 1080 /* 1081 * Setup a dummy root and fs_info for test/set super. This is because 1082 * we don't actually fill this stuff out until open_ctree, but we need 1083 * it for searching for existing supers, so this lets us do that and 1084 * then open_ctree will properly initialize everything later. 1085 */ 1086 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS); 1087 if (!fs_info) 1088 return ERR_PTR(-ENOMEM); 1089 1090 fs_info->fs_devices = fs_devices; 1091 1092 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS); 1093 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS); 1094 if (!fs_info->super_copy || !fs_info->super_for_commit) { 1095 error = -ENOMEM; 1096 goto error_fs_info; 1097 } 1098 1099 error = btrfs_open_devices(fs_devices, mode, fs_type); 1100 if (error) 1101 goto error_fs_info; 1102 1103 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) { 1104 error = -EACCES; 1105 goto error_close_devices; 1106 } 1107 1108 bdev = fs_devices->latest_bdev; 1109 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC, 1110 fs_info); 1111 if (IS_ERR(s)) { 1112 error = PTR_ERR(s); 1113 goto error_close_devices; 1114 } 1115 1116 if (s->s_root) { 1117 btrfs_close_devices(fs_devices); 1118 free_fs_info(fs_info); 1119 if ((flags ^ s->s_flags) & MS_RDONLY) 1120 error = -EBUSY; 1121 } else { 1122 char b[BDEVNAME_SIZE]; 1123 1124 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); 1125 btrfs_sb(s)->bdev_holder = fs_type; 1126 error = btrfs_fill_super(s, fs_devices, data, 1127 flags & MS_SILENT ? 1 : 0); 1128 } 1129 1130 root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error); 1131 if (IS_ERR(root)) 1132 deactivate_locked_super(s); 1133 1134 return root; 1135 1136 error_close_devices: 1137 btrfs_close_devices(fs_devices); 1138 error_fs_info: 1139 free_fs_info(fs_info); 1140 return ERR_PTR(error); 1141 } 1142 1143 static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit) 1144 { 1145 spin_lock_irq(&workers->lock); 1146 workers->max_workers = new_limit; 1147 spin_unlock_irq(&workers->lock); 1148 } 1149 1150 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info, 1151 int new_pool_size, int old_pool_size) 1152 { 1153 if (new_pool_size == old_pool_size) 1154 return; 1155 1156 fs_info->thread_pool_size = new_pool_size; 1157 1158 printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n", 1159 old_pool_size, new_pool_size); 1160 1161 btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size); 1162 btrfs_set_max_workers(&fs_info->workers, new_pool_size); 1163 btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size); 1164 btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size); 1165 btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size); 1166 btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size); 1167 btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size); 1168 btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size); 1169 btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size); 1170 btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size); 1171 btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size); 1172 btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size); 1173 btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size); 1174 btrfs_set_max_workers(&fs_info->scrub_workers, new_pool_size); 1175 } 1176 1177 static int btrfs_remount(struct super_block *sb, int *flags, char *data) 1178 { 1179 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1180 struct btrfs_root *root = fs_info->tree_root; 1181 unsigned old_flags = sb->s_flags; 1182 unsigned long old_opts = fs_info->mount_opt; 1183 unsigned long old_compress_type = fs_info->compress_type; 1184 u64 old_max_inline = fs_info->max_inline; 1185 u64 old_alloc_start = fs_info->alloc_start; 1186 int old_thread_pool_size = fs_info->thread_pool_size; 1187 unsigned int old_metadata_ratio = fs_info->metadata_ratio; 1188 int ret; 1189 1190 ret = btrfs_parse_options(root, data); 1191 if (ret) { 1192 ret = -EINVAL; 1193 goto restore; 1194 } 1195 1196 btrfs_resize_thread_pool(fs_info, 1197 fs_info->thread_pool_size, old_thread_pool_size); 1198 1199 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) 1200 return 0; 1201 1202 if (*flags & MS_RDONLY) { 1203 sb->s_flags |= MS_RDONLY; 1204 1205 ret = btrfs_commit_super(root); 1206 if (ret) 1207 goto restore; 1208 } else { 1209 if (fs_info->fs_devices->rw_devices == 0) { 1210 ret = -EACCES; 1211 goto restore; 1212 } 1213 1214 if (btrfs_super_log_root(fs_info->super_copy) != 0) { 1215 ret = -EINVAL; 1216 goto restore; 1217 } 1218 1219 ret = btrfs_cleanup_fs_roots(fs_info); 1220 if (ret) 1221 goto restore; 1222 1223 /* recover relocation */ 1224 ret = btrfs_recover_relocation(root); 1225 if (ret) 1226 goto restore; 1227 1228 ret = btrfs_resume_balance_async(fs_info); 1229 if (ret) 1230 goto restore; 1231 1232 sb->s_flags &= ~MS_RDONLY; 1233 } 1234 1235 return 0; 1236 1237 restore: 1238 /* We've hit an error - don't reset MS_RDONLY */ 1239 if (sb->s_flags & MS_RDONLY) 1240 old_flags |= MS_RDONLY; 1241 sb->s_flags = old_flags; 1242 fs_info->mount_opt = old_opts; 1243 fs_info->compress_type = old_compress_type; 1244 fs_info->max_inline = old_max_inline; 1245 fs_info->alloc_start = old_alloc_start; 1246 btrfs_resize_thread_pool(fs_info, 1247 old_thread_pool_size, fs_info->thread_pool_size); 1248 fs_info->metadata_ratio = old_metadata_ratio; 1249 return ret; 1250 } 1251 1252 /* Used to sort the devices by max_avail(descending sort) */ 1253 static int btrfs_cmp_device_free_bytes(const void *dev_info1, 1254 const void *dev_info2) 1255 { 1256 if (((struct btrfs_device_info *)dev_info1)->max_avail > 1257 ((struct btrfs_device_info *)dev_info2)->max_avail) 1258 return -1; 1259 else if (((struct btrfs_device_info *)dev_info1)->max_avail < 1260 ((struct btrfs_device_info *)dev_info2)->max_avail) 1261 return 1; 1262 else 1263 return 0; 1264 } 1265 1266 /* 1267 * sort the devices by max_avail, in which max free extent size of each device 1268 * is stored.(Descending Sort) 1269 */ 1270 static inline void btrfs_descending_sort_devices( 1271 struct btrfs_device_info *devices, 1272 size_t nr_devices) 1273 { 1274 sort(devices, nr_devices, sizeof(struct btrfs_device_info), 1275 btrfs_cmp_device_free_bytes, NULL); 1276 } 1277 1278 /* 1279 * The helper to calc the free space on the devices that can be used to store 1280 * file data. 1281 */ 1282 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) 1283 { 1284 struct btrfs_fs_info *fs_info = root->fs_info; 1285 struct btrfs_device_info *devices_info; 1286 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; 1287 struct btrfs_device *device; 1288 u64 skip_space; 1289 u64 type; 1290 u64 avail_space; 1291 u64 used_space; 1292 u64 min_stripe_size; 1293 int min_stripes = 1, num_stripes = 1; 1294 int i = 0, nr_devices; 1295 int ret; 1296 1297 nr_devices = fs_info->fs_devices->open_devices; 1298 BUG_ON(!nr_devices); 1299 1300 devices_info = kmalloc(sizeof(*devices_info) * nr_devices, 1301 GFP_NOFS); 1302 if (!devices_info) 1303 return -ENOMEM; 1304 1305 /* calc min stripe number for data space alloction */ 1306 type = btrfs_get_alloc_profile(root, 1); 1307 if (type & BTRFS_BLOCK_GROUP_RAID0) { 1308 min_stripes = 2; 1309 num_stripes = nr_devices; 1310 } else if (type & BTRFS_BLOCK_GROUP_RAID1) { 1311 min_stripes = 2; 1312 num_stripes = 2; 1313 } else if (type & BTRFS_BLOCK_GROUP_RAID10) { 1314 min_stripes = 4; 1315 num_stripes = 4; 1316 } 1317 1318 if (type & BTRFS_BLOCK_GROUP_DUP) 1319 min_stripe_size = 2 * BTRFS_STRIPE_LEN; 1320 else 1321 min_stripe_size = BTRFS_STRIPE_LEN; 1322 1323 list_for_each_entry(device, &fs_devices->devices, dev_list) { 1324 if (!device->in_fs_metadata || !device->bdev) 1325 continue; 1326 1327 avail_space = device->total_bytes - device->bytes_used; 1328 1329 /* align with stripe_len */ 1330 do_div(avail_space, BTRFS_STRIPE_LEN); 1331 avail_space *= BTRFS_STRIPE_LEN; 1332 1333 /* 1334 * In order to avoid overwritting the superblock on the drive, 1335 * btrfs starts at an offset of at least 1MB when doing chunk 1336 * allocation. 1337 */ 1338 skip_space = 1024 * 1024; 1339 1340 /* user can set the offset in fs_info->alloc_start. */ 1341 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <= 1342 device->total_bytes) 1343 skip_space = max(fs_info->alloc_start, skip_space); 1344 1345 /* 1346 * btrfs can not use the free space in [0, skip_space - 1], 1347 * we must subtract it from the total. In order to implement 1348 * it, we account the used space in this range first. 1349 */ 1350 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1, 1351 &used_space); 1352 if (ret) { 1353 kfree(devices_info); 1354 return ret; 1355 } 1356 1357 /* calc the free space in [0, skip_space - 1] */ 1358 skip_space -= used_space; 1359 1360 /* 1361 * we can use the free space in [0, skip_space - 1], subtract 1362 * it from the total. 1363 */ 1364 if (avail_space && avail_space >= skip_space) 1365 avail_space -= skip_space; 1366 else 1367 avail_space = 0; 1368 1369 if (avail_space < min_stripe_size) 1370 continue; 1371 1372 devices_info[i].dev = device; 1373 devices_info[i].max_avail = avail_space; 1374 1375 i++; 1376 } 1377 1378 nr_devices = i; 1379 1380 btrfs_descending_sort_devices(devices_info, nr_devices); 1381 1382 i = nr_devices - 1; 1383 avail_space = 0; 1384 while (nr_devices >= min_stripes) { 1385 if (num_stripes > nr_devices) 1386 num_stripes = nr_devices; 1387 1388 if (devices_info[i].max_avail >= min_stripe_size) { 1389 int j; 1390 u64 alloc_size; 1391 1392 avail_space += devices_info[i].max_avail * num_stripes; 1393 alloc_size = devices_info[i].max_avail; 1394 for (j = i + 1 - num_stripes; j <= i; j++) 1395 devices_info[j].max_avail -= alloc_size; 1396 } 1397 i--; 1398 nr_devices--; 1399 } 1400 1401 kfree(devices_info); 1402 *free_bytes = avail_space; 1403 return 0; 1404 } 1405 1406 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 1407 { 1408 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb); 1409 struct btrfs_super_block *disk_super = fs_info->super_copy; 1410 struct list_head *head = &fs_info->space_info; 1411 struct btrfs_space_info *found; 1412 u64 total_used = 0; 1413 u64 total_free_data = 0; 1414 int bits = dentry->d_sb->s_blocksize_bits; 1415 __be32 *fsid = (__be32 *)fs_info->fsid; 1416 int ret; 1417 1418 /* holding chunk_muext to avoid allocating new chunks */ 1419 mutex_lock(&fs_info->chunk_mutex); 1420 rcu_read_lock(); 1421 list_for_each_entry_rcu(found, head, list) { 1422 if (found->flags & BTRFS_BLOCK_GROUP_DATA) { 1423 total_free_data += found->disk_total - found->disk_used; 1424 total_free_data -= 1425 btrfs_account_ro_block_groups_free_space(found); 1426 } 1427 1428 total_used += found->disk_used; 1429 } 1430 rcu_read_unlock(); 1431 1432 buf->f_namelen = BTRFS_NAME_LEN; 1433 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits; 1434 buf->f_bfree = buf->f_blocks - (total_used >> bits); 1435 buf->f_bsize = dentry->d_sb->s_blocksize; 1436 buf->f_type = BTRFS_SUPER_MAGIC; 1437 buf->f_bavail = total_free_data; 1438 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data); 1439 if (ret) { 1440 mutex_unlock(&fs_info->chunk_mutex); 1441 return ret; 1442 } 1443 buf->f_bavail += total_free_data; 1444 buf->f_bavail = buf->f_bavail >> bits; 1445 mutex_unlock(&fs_info->chunk_mutex); 1446 1447 /* We treat it as constant endianness (it doesn't matter _which_) 1448 because we want the fsid to come out the same whether mounted 1449 on a big-endian or little-endian host */ 1450 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]); 1451 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]); 1452 /* Mask in the root object ID too, to disambiguate subvols */ 1453 buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32; 1454 buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid; 1455 1456 return 0; 1457 } 1458 1459 static void btrfs_kill_super(struct super_block *sb) 1460 { 1461 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1462 kill_anon_super(sb); 1463 free_fs_info(fs_info); 1464 } 1465 1466 static struct file_system_type btrfs_fs_type = { 1467 .owner = THIS_MODULE, 1468 .name = "btrfs", 1469 .mount = btrfs_mount, 1470 .kill_sb = btrfs_kill_super, 1471 .fs_flags = FS_REQUIRES_DEV, 1472 }; 1473 1474 /* 1475 * used by btrfsctl to scan devices when no FS is mounted 1476 */ 1477 static long btrfs_control_ioctl(struct file *file, unsigned int cmd, 1478 unsigned long arg) 1479 { 1480 struct btrfs_ioctl_vol_args *vol; 1481 struct btrfs_fs_devices *fs_devices; 1482 int ret = -ENOTTY; 1483 1484 if (!capable(CAP_SYS_ADMIN)) 1485 return -EPERM; 1486 1487 vol = memdup_user((void __user *)arg, sizeof(*vol)); 1488 if (IS_ERR(vol)) 1489 return PTR_ERR(vol); 1490 1491 switch (cmd) { 1492 case BTRFS_IOC_SCAN_DEV: 1493 ret = btrfs_scan_one_device(vol->name, FMODE_READ, 1494 &btrfs_fs_type, &fs_devices); 1495 break; 1496 case BTRFS_IOC_DEVICES_READY: 1497 ret = btrfs_scan_one_device(vol->name, FMODE_READ, 1498 &btrfs_fs_type, &fs_devices); 1499 if (ret) 1500 break; 1501 ret = !(fs_devices->num_devices == fs_devices->total_devices); 1502 break; 1503 } 1504 1505 kfree(vol); 1506 return ret; 1507 } 1508 1509 static int btrfs_freeze(struct super_block *sb) 1510 { 1511 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1512 mutex_lock(&fs_info->transaction_kthread_mutex); 1513 mutex_lock(&fs_info->cleaner_mutex); 1514 return 0; 1515 } 1516 1517 static int btrfs_unfreeze(struct super_block *sb) 1518 { 1519 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1520 mutex_unlock(&fs_info->cleaner_mutex); 1521 mutex_unlock(&fs_info->transaction_kthread_mutex); 1522 return 0; 1523 } 1524 1525 static int btrfs_show_devname(struct seq_file *m, struct dentry *root) 1526 { 1527 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb); 1528 struct btrfs_fs_devices *cur_devices; 1529 struct btrfs_device *dev, *first_dev = NULL; 1530 struct list_head *head; 1531 struct rcu_string *name; 1532 1533 mutex_lock(&fs_info->fs_devices->device_list_mutex); 1534 cur_devices = fs_info->fs_devices; 1535 while (cur_devices) { 1536 head = &cur_devices->devices; 1537 list_for_each_entry(dev, head, dev_list) { 1538 if (dev->missing) 1539 continue; 1540 if (!first_dev || dev->devid < first_dev->devid) 1541 first_dev = dev; 1542 } 1543 cur_devices = cur_devices->seed; 1544 } 1545 1546 if (first_dev) { 1547 rcu_read_lock(); 1548 name = rcu_dereference(first_dev->name); 1549 seq_escape(m, name->str, " \t\n\\"); 1550 rcu_read_unlock(); 1551 } else { 1552 WARN_ON(1); 1553 } 1554 mutex_unlock(&fs_info->fs_devices->device_list_mutex); 1555 return 0; 1556 } 1557 1558 static const struct super_operations btrfs_super_ops = { 1559 .drop_inode = btrfs_drop_inode, 1560 .evict_inode = btrfs_evict_inode, 1561 .put_super = btrfs_put_super, 1562 .sync_fs = btrfs_sync_fs, 1563 .show_options = btrfs_show_options, 1564 .show_devname = btrfs_show_devname, 1565 .write_inode = btrfs_write_inode, 1566 .alloc_inode = btrfs_alloc_inode, 1567 .destroy_inode = btrfs_destroy_inode, 1568 .statfs = btrfs_statfs, 1569 .remount_fs = btrfs_remount, 1570 .freeze_fs = btrfs_freeze, 1571 .unfreeze_fs = btrfs_unfreeze, 1572 }; 1573 1574 static const struct file_operations btrfs_ctl_fops = { 1575 .unlocked_ioctl = btrfs_control_ioctl, 1576 .compat_ioctl = btrfs_control_ioctl, 1577 .owner = THIS_MODULE, 1578 .llseek = noop_llseek, 1579 }; 1580 1581 static struct miscdevice btrfs_misc = { 1582 .minor = BTRFS_MINOR, 1583 .name = "btrfs-control", 1584 .fops = &btrfs_ctl_fops 1585 }; 1586 1587 MODULE_ALIAS_MISCDEV(BTRFS_MINOR); 1588 MODULE_ALIAS("devname:btrfs-control"); 1589 1590 static int btrfs_interface_init(void) 1591 { 1592 return misc_register(&btrfs_misc); 1593 } 1594 1595 static void btrfs_interface_exit(void) 1596 { 1597 if (misc_deregister(&btrfs_misc) < 0) 1598 printk(KERN_INFO "misc_deregister failed for control device"); 1599 } 1600 1601 static int __init init_btrfs_fs(void) 1602 { 1603 int err; 1604 1605 err = btrfs_init_sysfs(); 1606 if (err) 1607 return err; 1608 1609 btrfs_init_compress(); 1610 1611 err = btrfs_init_cachep(); 1612 if (err) 1613 goto free_compress; 1614 1615 err = extent_io_init(); 1616 if (err) 1617 goto free_cachep; 1618 1619 err = extent_map_init(); 1620 if (err) 1621 goto free_extent_io; 1622 1623 err = btrfs_delayed_inode_init(); 1624 if (err) 1625 goto free_extent_map; 1626 1627 err = btrfs_interface_init(); 1628 if (err) 1629 goto free_delayed_inode; 1630 1631 err = register_filesystem(&btrfs_fs_type); 1632 if (err) 1633 goto unregister_ioctl; 1634 1635 btrfs_init_lockdep(); 1636 1637 printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION); 1638 return 0; 1639 1640 unregister_ioctl: 1641 btrfs_interface_exit(); 1642 free_delayed_inode: 1643 btrfs_delayed_inode_exit(); 1644 free_extent_map: 1645 extent_map_exit(); 1646 free_extent_io: 1647 extent_io_exit(); 1648 free_cachep: 1649 btrfs_destroy_cachep(); 1650 free_compress: 1651 btrfs_exit_compress(); 1652 btrfs_exit_sysfs(); 1653 return err; 1654 } 1655 1656 static void __exit exit_btrfs_fs(void) 1657 { 1658 btrfs_destroy_cachep(); 1659 btrfs_delayed_inode_exit(); 1660 extent_map_exit(); 1661 extent_io_exit(); 1662 btrfs_interface_exit(); 1663 unregister_filesystem(&btrfs_fs_type); 1664 btrfs_exit_sysfs(); 1665 btrfs_cleanup_fs_uuids(); 1666 btrfs_exit_compress(); 1667 } 1668 1669 module_init(init_btrfs_fs) 1670 module_exit(exit_btrfs_fs) 1671 1672 MODULE_LICENSE("GPL"); 1673