1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2007 Oracle. All rights reserved. 4 */ 5 6 #include <linux/blkdev.h> 7 #include <linux/module.h> 8 #include <linux/fs.h> 9 #include <linux/pagemap.h> 10 #include <linux/highmem.h> 11 #include <linux/time.h> 12 #include <linux/init.h> 13 #include <linux/seq_file.h> 14 #include <linux/string.h> 15 #include <linux/backing-dev.h> 16 #include <linux/mount.h> 17 #include <linux/writeback.h> 18 #include <linux/statfs.h> 19 #include <linux/compat.h> 20 #include <linux/parser.h> 21 #include <linux/ctype.h> 22 #include <linux/namei.h> 23 #include <linux/miscdevice.h> 24 #include <linux/magic.h> 25 #include <linux/slab.h> 26 #include <linux/ratelimit.h> 27 #include <linux/crc32c.h> 28 #include <linux/btrfs.h> 29 #include <linux/security.h> 30 #include <linux/fs_parser.h> 31 #include "messages.h" 32 #include "delayed-inode.h" 33 #include "ctree.h" 34 #include "disk-io.h" 35 #include "transaction.h" 36 #include "btrfs_inode.h" 37 #include "props.h" 38 #include "xattr.h" 39 #include "bio.h" 40 #include "export.h" 41 #include "compression.h" 42 #include "dev-replace.h" 43 #include "free-space-cache.h" 44 #include "backref.h" 45 #include "space-info.h" 46 #include "sysfs.h" 47 #include "zoned.h" 48 #include "tests/btrfs-tests.h" 49 #include "block-group.h" 50 #include "discard.h" 51 #include "qgroup.h" 52 #include "raid56.h" 53 #include "fs.h" 54 #include "accessors.h" 55 #include "defrag.h" 56 #include "dir-item.h" 57 #include "ioctl.h" 58 #include "scrub.h" 59 #include "verity.h" 60 #include "super.h" 61 #include "extent-tree.h" 62 #define CREATE_TRACE_POINTS 63 #include <trace/events/btrfs.h> 64 65 static const struct super_operations btrfs_super_ops; 66 static struct file_system_type btrfs_fs_type; 67 68 static void btrfs_put_super(struct super_block *sb) 69 { 70 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 71 72 btrfs_info(fs_info, "last unmount of filesystem %pU", fs_info->fs_devices->fsid); 73 close_ctree(fs_info); 74 } 75 76 /* Store the mount options related information. */ 77 struct btrfs_fs_context { 78 char *subvol_name; 79 u64 subvol_objectid; 80 u64 max_inline; 81 u32 commit_interval; 82 u32 metadata_ratio; 83 u32 thread_pool_size; 84 unsigned long mount_opt; 85 unsigned long compress_type:4; 86 unsigned int compress_level; 87 refcount_t refs; 88 }; 89 90 enum { 91 Opt_acl, 92 Opt_clear_cache, 93 Opt_commit_interval, 94 Opt_compress, 95 Opt_compress_force, 96 Opt_compress_force_type, 97 Opt_compress_type, 98 Opt_degraded, 99 Opt_device, 100 Opt_fatal_errors, 101 Opt_flushoncommit, 102 Opt_max_inline, 103 Opt_barrier, 104 Opt_datacow, 105 Opt_datasum, 106 Opt_defrag, 107 Opt_discard, 108 Opt_discard_mode, 109 Opt_ratio, 110 Opt_rescan_uuid_tree, 111 Opt_skip_balance, 112 Opt_space_cache, 113 Opt_space_cache_version, 114 Opt_ssd, 115 Opt_ssd_spread, 116 Opt_subvol, 117 Opt_subvol_empty, 118 Opt_subvolid, 119 Opt_thread_pool, 120 Opt_treelog, 121 Opt_user_subvol_rm_allowed, 122 123 /* Rescue options */ 124 Opt_rescue, 125 Opt_usebackuproot, 126 Opt_nologreplay, 127 Opt_ignorebadroots, 128 Opt_ignoredatacsums, 129 Opt_rescue_all, 130 131 /* Debugging options */ 132 Opt_enospc_debug, 133 #ifdef CONFIG_BTRFS_DEBUG 134 Opt_fragment, Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all, 135 #endif 136 #ifdef CONFIG_BTRFS_FS_REF_VERIFY 137 Opt_ref_verify, 138 #endif 139 Opt_err, 140 }; 141 142 enum { 143 Opt_fatal_errors_panic, 144 Opt_fatal_errors_bug, 145 }; 146 147 static const struct constant_table btrfs_parameter_fatal_errors[] = { 148 { "panic", Opt_fatal_errors_panic }, 149 { "bug", Opt_fatal_errors_bug }, 150 {} 151 }; 152 153 enum { 154 Opt_discard_sync, 155 Opt_discard_async, 156 }; 157 158 static const struct constant_table btrfs_parameter_discard[] = { 159 { "sync", Opt_discard_sync }, 160 { "async", Opt_discard_async }, 161 {} 162 }; 163 164 enum { 165 Opt_space_cache_v1, 166 Opt_space_cache_v2, 167 }; 168 169 static const struct constant_table btrfs_parameter_space_cache[] = { 170 { "v1", Opt_space_cache_v1 }, 171 { "v2", Opt_space_cache_v2 }, 172 {} 173 }; 174 175 enum { 176 Opt_rescue_usebackuproot, 177 Opt_rescue_nologreplay, 178 Opt_rescue_ignorebadroots, 179 Opt_rescue_ignoredatacsums, 180 Opt_rescue_parameter_all, 181 }; 182 183 static const struct constant_table btrfs_parameter_rescue[] = { 184 { "usebackuproot", Opt_rescue_usebackuproot }, 185 { "nologreplay", Opt_rescue_nologreplay }, 186 { "ignorebadroots", Opt_rescue_ignorebadroots }, 187 { "ibadroots", Opt_rescue_ignorebadroots }, 188 { "ignoredatacsums", Opt_rescue_ignoredatacsums }, 189 { "idatacsums", Opt_rescue_ignoredatacsums }, 190 { "all", Opt_rescue_parameter_all }, 191 {} 192 }; 193 194 #ifdef CONFIG_BTRFS_DEBUG 195 enum { 196 Opt_fragment_parameter_data, 197 Opt_fragment_parameter_metadata, 198 Opt_fragment_parameter_all, 199 }; 200 201 static const struct constant_table btrfs_parameter_fragment[] = { 202 { "data", Opt_fragment_parameter_data }, 203 { "metadata", Opt_fragment_parameter_metadata }, 204 { "all", Opt_fragment_parameter_all }, 205 {} 206 }; 207 #endif 208 209 static const struct fs_parameter_spec btrfs_fs_parameters[] = { 210 fsparam_flag_no("acl", Opt_acl), 211 fsparam_flag_no("autodefrag", Opt_defrag), 212 fsparam_flag_no("barrier", Opt_barrier), 213 fsparam_flag("clear_cache", Opt_clear_cache), 214 fsparam_u32("commit", Opt_commit_interval), 215 fsparam_flag("compress", Opt_compress), 216 fsparam_string("compress", Opt_compress_type), 217 fsparam_flag("compress-force", Opt_compress_force), 218 fsparam_string("compress-force", Opt_compress_force_type), 219 fsparam_flag_no("datacow", Opt_datacow), 220 fsparam_flag_no("datasum", Opt_datasum), 221 fsparam_flag("degraded", Opt_degraded), 222 fsparam_string("device", Opt_device), 223 fsparam_flag_no("discard", Opt_discard), 224 fsparam_enum("discard", Opt_discard_mode, btrfs_parameter_discard), 225 fsparam_enum("fatal_errors", Opt_fatal_errors, btrfs_parameter_fatal_errors), 226 fsparam_flag_no("flushoncommit", Opt_flushoncommit), 227 fsparam_string("max_inline", Opt_max_inline), 228 fsparam_u32("metadata_ratio", Opt_ratio), 229 fsparam_flag("rescan_uuid_tree", Opt_rescan_uuid_tree), 230 fsparam_flag("skip_balance", Opt_skip_balance), 231 fsparam_flag_no("space_cache", Opt_space_cache), 232 fsparam_enum("space_cache", Opt_space_cache_version, btrfs_parameter_space_cache), 233 fsparam_flag_no("ssd", Opt_ssd), 234 fsparam_flag_no("ssd_spread", Opt_ssd_spread), 235 fsparam_string("subvol", Opt_subvol), 236 fsparam_flag("subvol=", Opt_subvol_empty), 237 fsparam_u64("subvolid", Opt_subvolid), 238 fsparam_u32("thread_pool", Opt_thread_pool), 239 fsparam_flag_no("treelog", Opt_treelog), 240 fsparam_flag("user_subvol_rm_allowed", Opt_user_subvol_rm_allowed), 241 242 /* Rescue options. */ 243 fsparam_enum("rescue", Opt_rescue, btrfs_parameter_rescue), 244 /* Deprecated, with alias rescue=nologreplay */ 245 __fsparam(NULL, "nologreplay", Opt_nologreplay, fs_param_deprecated, NULL), 246 /* Deprecated, with alias rescue=usebackuproot */ 247 __fsparam(NULL, "usebackuproot", Opt_usebackuproot, fs_param_deprecated, NULL), 248 249 /* Debugging options. */ 250 fsparam_flag_no("enospc_debug", Opt_enospc_debug), 251 #ifdef CONFIG_BTRFS_DEBUG 252 fsparam_enum("fragment", Opt_fragment, btrfs_parameter_fragment), 253 #endif 254 #ifdef CONFIG_BTRFS_FS_REF_VERIFY 255 fsparam_flag("ref_verify", Opt_ref_verify), 256 #endif 257 {} 258 }; 259 260 /* No support for restricting writes to btrfs devices yet... */ 261 static inline blk_mode_t btrfs_open_mode(struct fs_context *fc) 262 { 263 return sb_open_mode(fc->sb_flags) & ~BLK_OPEN_RESTRICT_WRITES; 264 } 265 266 static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param) 267 { 268 struct btrfs_fs_context *ctx = fc->fs_private; 269 struct fs_parse_result result; 270 int opt; 271 272 opt = fs_parse(fc, btrfs_fs_parameters, param, &result); 273 if (opt < 0) 274 return opt; 275 276 switch (opt) { 277 case Opt_degraded: 278 btrfs_set_opt(ctx->mount_opt, DEGRADED); 279 break; 280 case Opt_subvol_empty: 281 /* 282 * This exists because we used to allow it on accident, so we're 283 * keeping it to maintain ABI. See 37becec95ac3 ("Btrfs: allow 284 * empty subvol= again"). 285 */ 286 break; 287 case Opt_subvol: 288 kfree(ctx->subvol_name); 289 ctx->subvol_name = kstrdup(param->string, GFP_KERNEL); 290 if (!ctx->subvol_name) 291 return -ENOMEM; 292 break; 293 case Opt_subvolid: 294 ctx->subvol_objectid = result.uint_64; 295 296 /* subvolid=0 means give me the original fs_tree. */ 297 if (!ctx->subvol_objectid) 298 ctx->subvol_objectid = BTRFS_FS_TREE_OBJECTID; 299 break; 300 case Opt_device: { 301 struct btrfs_device *device; 302 blk_mode_t mode = btrfs_open_mode(fc); 303 304 mutex_lock(&uuid_mutex); 305 device = btrfs_scan_one_device(param->string, mode, false); 306 mutex_unlock(&uuid_mutex); 307 if (IS_ERR(device)) 308 return PTR_ERR(device); 309 break; 310 } 311 case Opt_datasum: 312 if (result.negated) { 313 btrfs_set_opt(ctx->mount_opt, NODATASUM); 314 } else { 315 btrfs_clear_opt(ctx->mount_opt, NODATACOW); 316 btrfs_clear_opt(ctx->mount_opt, NODATASUM); 317 } 318 break; 319 case Opt_datacow: 320 if (result.negated) { 321 btrfs_clear_opt(ctx->mount_opt, COMPRESS); 322 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS); 323 btrfs_set_opt(ctx->mount_opt, NODATACOW); 324 btrfs_set_opt(ctx->mount_opt, NODATASUM); 325 } else { 326 btrfs_clear_opt(ctx->mount_opt, NODATACOW); 327 } 328 break; 329 case Opt_compress_force: 330 case Opt_compress_force_type: 331 btrfs_set_opt(ctx->mount_opt, FORCE_COMPRESS); 332 fallthrough; 333 case Opt_compress: 334 case Opt_compress_type: 335 if (opt == Opt_compress || opt == Opt_compress_force) { 336 ctx->compress_type = BTRFS_COMPRESS_ZLIB; 337 ctx->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL; 338 btrfs_set_opt(ctx->mount_opt, COMPRESS); 339 btrfs_clear_opt(ctx->mount_opt, NODATACOW); 340 btrfs_clear_opt(ctx->mount_opt, NODATASUM); 341 } else if (strncmp(param->string, "zlib", 4) == 0) { 342 ctx->compress_type = BTRFS_COMPRESS_ZLIB; 343 ctx->compress_level = 344 btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB, 345 param->string + 4); 346 btrfs_set_opt(ctx->mount_opt, COMPRESS); 347 btrfs_clear_opt(ctx->mount_opt, NODATACOW); 348 btrfs_clear_opt(ctx->mount_opt, NODATASUM); 349 } else if (strncmp(param->string, "lzo", 3) == 0) { 350 ctx->compress_type = BTRFS_COMPRESS_LZO; 351 ctx->compress_level = 0; 352 btrfs_set_opt(ctx->mount_opt, COMPRESS); 353 btrfs_clear_opt(ctx->mount_opt, NODATACOW); 354 btrfs_clear_opt(ctx->mount_opt, NODATASUM); 355 } else if (strncmp(param->string, "zstd", 4) == 0) { 356 ctx->compress_type = BTRFS_COMPRESS_ZSTD; 357 ctx->compress_level = 358 btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD, 359 param->string + 4); 360 btrfs_set_opt(ctx->mount_opt, COMPRESS); 361 btrfs_clear_opt(ctx->mount_opt, NODATACOW); 362 btrfs_clear_opt(ctx->mount_opt, NODATASUM); 363 } else if (strncmp(param->string, "no", 2) == 0) { 364 ctx->compress_level = 0; 365 ctx->compress_type = 0; 366 btrfs_clear_opt(ctx->mount_opt, COMPRESS); 367 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS); 368 } else { 369 btrfs_err(NULL, "unrecognized compression value %s", 370 param->string); 371 return -EINVAL; 372 } 373 break; 374 case Opt_ssd: 375 if (result.negated) { 376 btrfs_set_opt(ctx->mount_opt, NOSSD); 377 btrfs_clear_opt(ctx->mount_opt, SSD); 378 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD); 379 } else { 380 btrfs_set_opt(ctx->mount_opt, SSD); 381 btrfs_clear_opt(ctx->mount_opt, NOSSD); 382 } 383 break; 384 case Opt_ssd_spread: 385 if (result.negated) { 386 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD); 387 } else { 388 btrfs_set_opt(ctx->mount_opt, SSD); 389 btrfs_set_opt(ctx->mount_opt, SSD_SPREAD); 390 btrfs_clear_opt(ctx->mount_opt, NOSSD); 391 } 392 break; 393 case Opt_barrier: 394 if (result.negated) 395 btrfs_set_opt(ctx->mount_opt, NOBARRIER); 396 else 397 btrfs_clear_opt(ctx->mount_opt, NOBARRIER); 398 break; 399 case Opt_thread_pool: 400 if (result.uint_32 == 0) { 401 btrfs_err(NULL, "invalid value 0 for thread_pool"); 402 return -EINVAL; 403 } 404 ctx->thread_pool_size = result.uint_32; 405 break; 406 case Opt_max_inline: 407 ctx->max_inline = memparse(param->string, NULL); 408 break; 409 case Opt_acl: 410 if (result.negated) { 411 fc->sb_flags &= ~SB_POSIXACL; 412 } else { 413 #ifdef CONFIG_BTRFS_FS_POSIX_ACL 414 fc->sb_flags |= SB_POSIXACL; 415 #else 416 btrfs_err(NULL, "support for ACL not compiled in"); 417 return -EINVAL; 418 #endif 419 } 420 /* 421 * VFS limits the ability to toggle ACL on and off via remount, 422 * despite every file system allowing this. This seems to be 423 * an oversight since we all do, but it'll fail if we're 424 * remounting. So don't set the mask here, we'll check it in 425 * btrfs_reconfigure and do the toggling ourselves. 426 */ 427 if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE) 428 fc->sb_flags_mask |= SB_POSIXACL; 429 break; 430 case Opt_treelog: 431 if (result.negated) 432 btrfs_set_opt(ctx->mount_opt, NOTREELOG); 433 else 434 btrfs_clear_opt(ctx->mount_opt, NOTREELOG); 435 break; 436 case Opt_nologreplay: 437 btrfs_warn(NULL, 438 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead"); 439 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY); 440 break; 441 case Opt_flushoncommit: 442 if (result.negated) 443 btrfs_clear_opt(ctx->mount_opt, FLUSHONCOMMIT); 444 else 445 btrfs_set_opt(ctx->mount_opt, FLUSHONCOMMIT); 446 break; 447 case Opt_ratio: 448 ctx->metadata_ratio = result.uint_32; 449 break; 450 case Opt_discard: 451 if (result.negated) { 452 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC); 453 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC); 454 btrfs_set_opt(ctx->mount_opt, NODISCARD); 455 } else { 456 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC); 457 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC); 458 } 459 break; 460 case Opt_discard_mode: 461 switch (result.uint_32) { 462 case Opt_discard_sync: 463 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC); 464 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC); 465 break; 466 case Opt_discard_async: 467 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC); 468 btrfs_set_opt(ctx->mount_opt, DISCARD_ASYNC); 469 break; 470 default: 471 btrfs_err(NULL, "unrecognized discard mode value %s", 472 param->key); 473 return -EINVAL; 474 } 475 btrfs_clear_opt(ctx->mount_opt, NODISCARD); 476 break; 477 case Opt_space_cache: 478 if (result.negated) { 479 btrfs_set_opt(ctx->mount_opt, NOSPACECACHE); 480 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE); 481 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE); 482 } else { 483 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE); 484 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE); 485 } 486 break; 487 case Opt_space_cache_version: 488 switch (result.uint_32) { 489 case Opt_space_cache_v1: 490 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE); 491 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE); 492 break; 493 case Opt_space_cache_v2: 494 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE); 495 btrfs_set_opt(ctx->mount_opt, FREE_SPACE_TREE); 496 break; 497 default: 498 btrfs_err(NULL, "unrecognized space_cache value %s", 499 param->key); 500 return -EINVAL; 501 } 502 break; 503 case Opt_rescan_uuid_tree: 504 btrfs_set_opt(ctx->mount_opt, RESCAN_UUID_TREE); 505 break; 506 case Opt_clear_cache: 507 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE); 508 break; 509 case Opt_user_subvol_rm_allowed: 510 btrfs_set_opt(ctx->mount_opt, USER_SUBVOL_RM_ALLOWED); 511 break; 512 case Opt_enospc_debug: 513 if (result.negated) 514 btrfs_clear_opt(ctx->mount_opt, ENOSPC_DEBUG); 515 else 516 btrfs_set_opt(ctx->mount_opt, ENOSPC_DEBUG); 517 break; 518 case Opt_defrag: 519 if (result.negated) 520 btrfs_clear_opt(ctx->mount_opt, AUTO_DEFRAG); 521 else 522 btrfs_set_opt(ctx->mount_opt, AUTO_DEFRAG); 523 break; 524 case Opt_usebackuproot: 525 btrfs_warn(NULL, 526 "'usebackuproot' is deprecated, use 'rescue=usebackuproot' instead"); 527 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT); 528 529 /* If we're loading the backup roots we can't trust the space cache. */ 530 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE); 531 break; 532 case Opt_skip_balance: 533 btrfs_set_opt(ctx->mount_opt, SKIP_BALANCE); 534 break; 535 case Opt_fatal_errors: 536 switch (result.uint_32) { 537 case Opt_fatal_errors_panic: 538 btrfs_set_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR); 539 break; 540 case Opt_fatal_errors_bug: 541 btrfs_clear_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR); 542 break; 543 default: 544 btrfs_err(NULL, "unrecognized fatal_errors value %s", 545 param->key); 546 return -EINVAL; 547 } 548 break; 549 case Opt_commit_interval: 550 ctx->commit_interval = result.uint_32; 551 if (ctx->commit_interval == 0) 552 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL; 553 break; 554 case Opt_rescue: 555 switch (result.uint_32) { 556 case Opt_rescue_usebackuproot: 557 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT); 558 break; 559 case Opt_rescue_nologreplay: 560 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY); 561 break; 562 case Opt_rescue_ignorebadroots: 563 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS); 564 break; 565 case Opt_rescue_ignoredatacsums: 566 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS); 567 break; 568 case Opt_rescue_parameter_all: 569 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS); 570 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS); 571 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY); 572 break; 573 default: 574 btrfs_info(NULL, "unrecognized rescue option '%s'", 575 param->key); 576 return -EINVAL; 577 } 578 break; 579 #ifdef CONFIG_BTRFS_DEBUG 580 case Opt_fragment: 581 switch (result.uint_32) { 582 case Opt_fragment_parameter_all: 583 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA); 584 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA); 585 break; 586 case Opt_fragment_parameter_metadata: 587 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA); 588 break; 589 case Opt_fragment_parameter_data: 590 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA); 591 break; 592 default: 593 btrfs_info(NULL, "unrecognized fragment option '%s'", 594 param->key); 595 return -EINVAL; 596 } 597 break; 598 #endif 599 #ifdef CONFIG_BTRFS_FS_REF_VERIFY 600 case Opt_ref_verify: 601 btrfs_set_opt(ctx->mount_opt, REF_VERIFY); 602 break; 603 #endif 604 default: 605 btrfs_err(NULL, "unrecognized mount option '%s'", param->key); 606 return -EINVAL; 607 } 608 609 return 0; 610 } 611 612 /* 613 * Some options only have meaning at mount time and shouldn't persist across 614 * remounts, or be displayed. Clear these at the end of mount and remount code 615 * paths. 616 */ 617 static void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info) 618 { 619 btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT); 620 btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE); 621 btrfs_clear_opt(fs_info->mount_opt, NOSPACECACHE); 622 } 623 624 static bool check_ro_option(struct btrfs_fs_info *fs_info, 625 unsigned long mount_opt, unsigned long opt, 626 const char *opt_name) 627 { 628 if (mount_opt & opt) { 629 btrfs_err(fs_info, "%s must be used with ro mount option", 630 opt_name); 631 return true; 632 } 633 return false; 634 } 635 636 bool btrfs_check_options(struct btrfs_fs_info *info, unsigned long *mount_opt, 637 unsigned long flags) 638 { 639 bool ret = true; 640 641 if (!(flags & SB_RDONLY) && 642 (check_ro_option(info, *mount_opt, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") || 643 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") || 644 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))) 645 ret = false; 646 647 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) && 648 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE) && 649 !btrfs_raw_test_opt(*mount_opt, CLEAR_CACHE)) { 650 btrfs_err(info, "cannot disable free-space-tree"); 651 ret = false; 652 } 653 if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) && 654 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) { 655 btrfs_err(info, "cannot disable free-space-tree with block-group-tree feature"); 656 ret = false; 657 } 658 659 if (btrfs_check_mountopts_zoned(info, mount_opt)) 660 ret = false; 661 662 if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) { 663 if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE)) 664 btrfs_info(info, "disk space caching is enabled"); 665 if (btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) 666 btrfs_info(info, "using free-space-tree"); 667 } 668 669 return ret; 670 } 671 672 /* 673 * This is subtle, we only call this during open_ctree(). We need to pre-load 674 * the mount options with the on-disk settings. Before the new mount API took 675 * effect we would do this on mount and remount. With the new mount API we'll 676 * only do this on the initial mount. 677 * 678 * This isn't a change in behavior, because we're using the current state of the 679 * file system to set the current mount options. If you mounted with special 680 * options to disable these features and then remounted we wouldn't revert the 681 * settings, because mounting without these features cleared the on-disk 682 * settings, so this being called on re-mount is not needed. 683 */ 684 void btrfs_set_free_space_cache_settings(struct btrfs_fs_info *fs_info) 685 { 686 if (fs_info->sectorsize < PAGE_SIZE) { 687 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE); 688 if (!btrfs_test_opt(fs_info, FREE_SPACE_TREE)) { 689 btrfs_info(fs_info, 690 "forcing free space tree for sector size %u with page size %lu", 691 fs_info->sectorsize, PAGE_SIZE); 692 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE); 693 } 694 } 695 696 /* 697 * At this point our mount options are populated, so we only mess with 698 * these settings if we don't have any settings already. 699 */ 700 if (btrfs_test_opt(fs_info, FREE_SPACE_TREE)) 701 return; 702 703 if (btrfs_is_zoned(fs_info) && 704 btrfs_free_space_cache_v1_active(fs_info)) { 705 btrfs_info(fs_info, "zoned: clearing existing space cache"); 706 btrfs_set_super_cache_generation(fs_info->super_copy, 0); 707 return; 708 } 709 710 if (btrfs_test_opt(fs_info, SPACE_CACHE)) 711 return; 712 713 if (btrfs_test_opt(fs_info, NOSPACECACHE)) 714 return; 715 716 /* 717 * At this point we don't have explicit options set by the user, set 718 * them ourselves based on the state of the file system. 719 */ 720 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) 721 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE); 722 else if (btrfs_free_space_cache_v1_active(fs_info)) 723 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE); 724 } 725 726 static void set_device_specific_options(struct btrfs_fs_info *fs_info) 727 { 728 if (!btrfs_test_opt(fs_info, NOSSD) && 729 !fs_info->fs_devices->rotating) 730 btrfs_set_opt(fs_info->mount_opt, SSD); 731 732 /* 733 * For devices supporting discard turn on discard=async automatically, 734 * unless it's already set or disabled. This could be turned off by 735 * nodiscard for the same mount. 736 * 737 * The zoned mode piggy backs on the discard functionality for 738 * resetting a zone. There is no reason to delay the zone reset as it is 739 * fast enough. So, do not enable async discard for zoned mode. 740 */ 741 if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) || 742 btrfs_test_opt(fs_info, DISCARD_ASYNC) || 743 btrfs_test_opt(fs_info, NODISCARD)) && 744 fs_info->fs_devices->discardable && 745 !btrfs_is_zoned(fs_info)) 746 btrfs_set_opt(fs_info->mount_opt, DISCARD_ASYNC); 747 } 748 749 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info, 750 u64 subvol_objectid) 751 { 752 struct btrfs_root *root = fs_info->tree_root; 753 struct btrfs_root *fs_root = NULL; 754 struct btrfs_root_ref *root_ref; 755 struct btrfs_inode_ref *inode_ref; 756 struct btrfs_key key; 757 struct btrfs_path *path = NULL; 758 char *name = NULL, *ptr; 759 u64 dirid; 760 int len; 761 int ret; 762 763 path = btrfs_alloc_path(); 764 if (!path) { 765 ret = -ENOMEM; 766 goto err; 767 } 768 769 name = kmalloc(PATH_MAX, GFP_KERNEL); 770 if (!name) { 771 ret = -ENOMEM; 772 goto err; 773 } 774 ptr = name + PATH_MAX - 1; 775 ptr[0] = '\0'; 776 777 /* 778 * Walk up the subvolume trees in the tree of tree roots by root 779 * backrefs until we hit the top-level subvolume. 780 */ 781 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) { 782 key.objectid = subvol_objectid; 783 key.type = BTRFS_ROOT_BACKREF_KEY; 784 key.offset = (u64)-1; 785 786 ret = btrfs_search_backwards(root, &key, path); 787 if (ret < 0) { 788 goto err; 789 } else if (ret > 0) { 790 ret = -ENOENT; 791 goto err; 792 } 793 794 subvol_objectid = key.offset; 795 796 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0], 797 struct btrfs_root_ref); 798 len = btrfs_root_ref_name_len(path->nodes[0], root_ref); 799 ptr -= len + 1; 800 if (ptr < name) { 801 ret = -ENAMETOOLONG; 802 goto err; 803 } 804 read_extent_buffer(path->nodes[0], ptr + 1, 805 (unsigned long)(root_ref + 1), len); 806 ptr[0] = '/'; 807 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref); 808 btrfs_release_path(path); 809 810 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true); 811 if (IS_ERR(fs_root)) { 812 ret = PTR_ERR(fs_root); 813 fs_root = NULL; 814 goto err; 815 } 816 817 /* 818 * Walk up the filesystem tree by inode refs until we hit the 819 * root directory. 820 */ 821 while (dirid != BTRFS_FIRST_FREE_OBJECTID) { 822 key.objectid = dirid; 823 key.type = BTRFS_INODE_REF_KEY; 824 key.offset = (u64)-1; 825 826 ret = btrfs_search_backwards(fs_root, &key, path); 827 if (ret < 0) { 828 goto err; 829 } else if (ret > 0) { 830 ret = -ENOENT; 831 goto err; 832 } 833 834 dirid = key.offset; 835 836 inode_ref = btrfs_item_ptr(path->nodes[0], 837 path->slots[0], 838 struct btrfs_inode_ref); 839 len = btrfs_inode_ref_name_len(path->nodes[0], 840 inode_ref); 841 ptr -= len + 1; 842 if (ptr < name) { 843 ret = -ENAMETOOLONG; 844 goto err; 845 } 846 read_extent_buffer(path->nodes[0], ptr + 1, 847 (unsigned long)(inode_ref + 1), len); 848 ptr[0] = '/'; 849 btrfs_release_path(path); 850 } 851 btrfs_put_root(fs_root); 852 fs_root = NULL; 853 } 854 855 btrfs_free_path(path); 856 if (ptr == name + PATH_MAX - 1) { 857 name[0] = '/'; 858 name[1] = '\0'; 859 } else { 860 memmove(name, ptr, name + PATH_MAX - ptr); 861 } 862 return name; 863 864 err: 865 btrfs_put_root(fs_root); 866 btrfs_free_path(path); 867 kfree(name); 868 return ERR_PTR(ret); 869 } 870 871 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid) 872 { 873 struct btrfs_root *root = fs_info->tree_root; 874 struct btrfs_dir_item *di; 875 struct btrfs_path *path; 876 struct btrfs_key location; 877 struct fscrypt_str name = FSTR_INIT("default", 7); 878 u64 dir_id; 879 880 path = btrfs_alloc_path(); 881 if (!path) 882 return -ENOMEM; 883 884 /* 885 * Find the "default" dir item which points to the root item that we 886 * will mount by default if we haven't been given a specific subvolume 887 * to mount. 888 */ 889 dir_id = btrfs_super_root_dir(fs_info->super_copy); 890 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0); 891 if (IS_ERR(di)) { 892 btrfs_free_path(path); 893 return PTR_ERR(di); 894 } 895 if (!di) { 896 /* 897 * Ok the default dir item isn't there. This is weird since 898 * it's always been there, but don't freak out, just try and 899 * mount the top-level subvolume. 900 */ 901 btrfs_free_path(path); 902 *objectid = BTRFS_FS_TREE_OBJECTID; 903 return 0; 904 } 905 906 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); 907 btrfs_free_path(path); 908 *objectid = location.objectid; 909 return 0; 910 } 911 912 static int btrfs_fill_super(struct super_block *sb, 913 struct btrfs_fs_devices *fs_devices, 914 void *data) 915 { 916 struct inode *inode; 917 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 918 int err; 919 920 sb->s_maxbytes = MAX_LFS_FILESIZE; 921 sb->s_magic = BTRFS_SUPER_MAGIC; 922 sb->s_op = &btrfs_super_ops; 923 sb->s_d_op = &btrfs_dentry_operations; 924 sb->s_export_op = &btrfs_export_ops; 925 #ifdef CONFIG_FS_VERITY 926 sb->s_vop = &btrfs_verityops; 927 #endif 928 sb->s_xattr = btrfs_xattr_handlers; 929 sb->s_time_gran = 1; 930 sb->s_iflags |= SB_I_CGROUPWB; 931 932 err = super_setup_bdi(sb); 933 if (err) { 934 btrfs_err(fs_info, "super_setup_bdi failed"); 935 return err; 936 } 937 938 err = open_ctree(sb, fs_devices, (char *)data); 939 if (err) { 940 btrfs_err(fs_info, "open_ctree failed"); 941 return err; 942 } 943 944 inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root); 945 if (IS_ERR(inode)) { 946 err = PTR_ERR(inode); 947 btrfs_handle_fs_error(fs_info, err, NULL); 948 goto fail_close; 949 } 950 951 sb->s_root = d_make_root(inode); 952 if (!sb->s_root) { 953 err = -ENOMEM; 954 goto fail_close; 955 } 956 957 sb->s_flags |= SB_ACTIVE; 958 return 0; 959 960 fail_close: 961 close_ctree(fs_info); 962 return err; 963 } 964 965 int btrfs_sync_fs(struct super_block *sb, int wait) 966 { 967 struct btrfs_trans_handle *trans; 968 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 969 struct btrfs_root *root = fs_info->tree_root; 970 971 trace_btrfs_sync_fs(fs_info, wait); 972 973 if (!wait) { 974 filemap_flush(fs_info->btree_inode->i_mapping); 975 return 0; 976 } 977 978 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1); 979 980 trans = btrfs_attach_transaction_barrier(root); 981 if (IS_ERR(trans)) { 982 /* no transaction, don't bother */ 983 if (PTR_ERR(trans) == -ENOENT) { 984 /* 985 * Exit unless we have some pending changes 986 * that need to go through commit 987 */ 988 if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT, 989 &fs_info->flags)) 990 return 0; 991 /* 992 * A non-blocking test if the fs is frozen. We must not 993 * start a new transaction here otherwise a deadlock 994 * happens. The pending operations are delayed to the 995 * next commit after thawing. 996 */ 997 if (sb_start_write_trylock(sb)) 998 sb_end_write(sb); 999 else 1000 return 0; 1001 trans = btrfs_start_transaction(root, 0); 1002 } 1003 if (IS_ERR(trans)) 1004 return PTR_ERR(trans); 1005 } 1006 return btrfs_commit_transaction(trans); 1007 } 1008 1009 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed) 1010 { 1011 seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s); 1012 *printed = true; 1013 } 1014 1015 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) 1016 { 1017 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb); 1018 const char *compress_type; 1019 const char *subvol_name; 1020 bool printed = false; 1021 1022 if (btrfs_test_opt(info, DEGRADED)) 1023 seq_puts(seq, ",degraded"); 1024 if (btrfs_test_opt(info, NODATASUM)) 1025 seq_puts(seq, ",nodatasum"); 1026 if (btrfs_test_opt(info, NODATACOW)) 1027 seq_puts(seq, ",nodatacow"); 1028 if (btrfs_test_opt(info, NOBARRIER)) 1029 seq_puts(seq, ",nobarrier"); 1030 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE) 1031 seq_printf(seq, ",max_inline=%llu", info->max_inline); 1032 if (info->thread_pool_size != min_t(unsigned long, 1033 num_online_cpus() + 2, 8)) 1034 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size); 1035 if (btrfs_test_opt(info, COMPRESS)) { 1036 compress_type = btrfs_compress_type2str(info->compress_type); 1037 if (btrfs_test_opt(info, FORCE_COMPRESS)) 1038 seq_printf(seq, ",compress-force=%s", compress_type); 1039 else 1040 seq_printf(seq, ",compress=%s", compress_type); 1041 if (info->compress_level) 1042 seq_printf(seq, ":%d", info->compress_level); 1043 } 1044 if (btrfs_test_opt(info, NOSSD)) 1045 seq_puts(seq, ",nossd"); 1046 if (btrfs_test_opt(info, SSD_SPREAD)) 1047 seq_puts(seq, ",ssd_spread"); 1048 else if (btrfs_test_opt(info, SSD)) 1049 seq_puts(seq, ",ssd"); 1050 if (btrfs_test_opt(info, NOTREELOG)) 1051 seq_puts(seq, ",notreelog"); 1052 if (btrfs_test_opt(info, NOLOGREPLAY)) 1053 print_rescue_option(seq, "nologreplay", &printed); 1054 if (btrfs_test_opt(info, USEBACKUPROOT)) 1055 print_rescue_option(seq, "usebackuproot", &printed); 1056 if (btrfs_test_opt(info, IGNOREBADROOTS)) 1057 print_rescue_option(seq, "ignorebadroots", &printed); 1058 if (btrfs_test_opt(info, IGNOREDATACSUMS)) 1059 print_rescue_option(seq, "ignoredatacsums", &printed); 1060 if (btrfs_test_opt(info, FLUSHONCOMMIT)) 1061 seq_puts(seq, ",flushoncommit"); 1062 if (btrfs_test_opt(info, DISCARD_SYNC)) 1063 seq_puts(seq, ",discard"); 1064 if (btrfs_test_opt(info, DISCARD_ASYNC)) 1065 seq_puts(seq, ",discard=async"); 1066 if (!(info->sb->s_flags & SB_POSIXACL)) 1067 seq_puts(seq, ",noacl"); 1068 if (btrfs_free_space_cache_v1_active(info)) 1069 seq_puts(seq, ",space_cache"); 1070 else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE)) 1071 seq_puts(seq, ",space_cache=v2"); 1072 else 1073 seq_puts(seq, ",nospace_cache"); 1074 if (btrfs_test_opt(info, RESCAN_UUID_TREE)) 1075 seq_puts(seq, ",rescan_uuid_tree"); 1076 if (btrfs_test_opt(info, CLEAR_CACHE)) 1077 seq_puts(seq, ",clear_cache"); 1078 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED)) 1079 seq_puts(seq, ",user_subvol_rm_allowed"); 1080 if (btrfs_test_opt(info, ENOSPC_DEBUG)) 1081 seq_puts(seq, ",enospc_debug"); 1082 if (btrfs_test_opt(info, AUTO_DEFRAG)) 1083 seq_puts(seq, ",autodefrag"); 1084 if (btrfs_test_opt(info, SKIP_BALANCE)) 1085 seq_puts(seq, ",skip_balance"); 1086 if (info->metadata_ratio) 1087 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio); 1088 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR)) 1089 seq_puts(seq, ",fatal_errors=panic"); 1090 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL) 1091 seq_printf(seq, ",commit=%u", info->commit_interval); 1092 #ifdef CONFIG_BTRFS_DEBUG 1093 if (btrfs_test_opt(info, FRAGMENT_DATA)) 1094 seq_puts(seq, ",fragment=data"); 1095 if (btrfs_test_opt(info, FRAGMENT_METADATA)) 1096 seq_puts(seq, ",fragment=metadata"); 1097 #endif 1098 if (btrfs_test_opt(info, REF_VERIFY)) 1099 seq_puts(seq, ",ref_verify"); 1100 seq_printf(seq, ",subvolid=%llu", 1101 BTRFS_I(d_inode(dentry))->root->root_key.objectid); 1102 subvol_name = btrfs_get_subvol_name_from_objectid(info, 1103 BTRFS_I(d_inode(dentry))->root->root_key.objectid); 1104 if (!IS_ERR(subvol_name)) { 1105 seq_puts(seq, ",subvol="); 1106 seq_escape(seq, subvol_name, " \t\n\\"); 1107 kfree(subvol_name); 1108 } 1109 return 0; 1110 } 1111 1112 /* 1113 * subvolumes are identified by ino 256 1114 */ 1115 static inline int is_subvolume_inode(struct inode *inode) 1116 { 1117 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) 1118 return 1; 1119 return 0; 1120 } 1121 1122 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid, 1123 struct vfsmount *mnt) 1124 { 1125 struct dentry *root; 1126 int ret; 1127 1128 if (!subvol_name) { 1129 if (!subvol_objectid) { 1130 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb), 1131 &subvol_objectid); 1132 if (ret) { 1133 root = ERR_PTR(ret); 1134 goto out; 1135 } 1136 } 1137 subvol_name = btrfs_get_subvol_name_from_objectid( 1138 btrfs_sb(mnt->mnt_sb), subvol_objectid); 1139 if (IS_ERR(subvol_name)) { 1140 root = ERR_CAST(subvol_name); 1141 subvol_name = NULL; 1142 goto out; 1143 } 1144 1145 } 1146 1147 root = mount_subtree(mnt, subvol_name); 1148 /* mount_subtree() drops our reference on the vfsmount. */ 1149 mnt = NULL; 1150 1151 if (!IS_ERR(root)) { 1152 struct super_block *s = root->d_sb; 1153 struct btrfs_fs_info *fs_info = btrfs_sb(s); 1154 struct inode *root_inode = d_inode(root); 1155 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid; 1156 1157 ret = 0; 1158 if (!is_subvolume_inode(root_inode)) { 1159 btrfs_err(fs_info, "'%s' is not a valid subvolume", 1160 subvol_name); 1161 ret = -EINVAL; 1162 } 1163 if (subvol_objectid && root_objectid != subvol_objectid) { 1164 /* 1165 * This will also catch a race condition where a 1166 * subvolume which was passed by ID is renamed and 1167 * another subvolume is renamed over the old location. 1168 */ 1169 btrfs_err(fs_info, 1170 "subvol '%s' does not match subvolid %llu", 1171 subvol_name, subvol_objectid); 1172 ret = -EINVAL; 1173 } 1174 if (ret) { 1175 dput(root); 1176 root = ERR_PTR(ret); 1177 deactivate_locked_super(s); 1178 } 1179 } 1180 1181 out: 1182 mntput(mnt); 1183 kfree(subvol_name); 1184 return root; 1185 } 1186 1187 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info, 1188 u32 new_pool_size, u32 old_pool_size) 1189 { 1190 if (new_pool_size == old_pool_size) 1191 return; 1192 1193 fs_info->thread_pool_size = new_pool_size; 1194 1195 btrfs_info(fs_info, "resize thread pool %d -> %d", 1196 old_pool_size, new_pool_size); 1197 1198 btrfs_workqueue_set_max(fs_info->workers, new_pool_size); 1199 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size); 1200 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size); 1201 workqueue_set_max_active(fs_info->endio_workers, new_pool_size); 1202 workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size); 1203 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size); 1204 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size); 1205 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size); 1206 } 1207 1208 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info, 1209 unsigned long old_opts, int flags) 1210 { 1211 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) && 1212 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || 1213 (flags & SB_RDONLY))) { 1214 /* wait for any defraggers to finish */ 1215 wait_event(fs_info->transaction_wait, 1216 (atomic_read(&fs_info->defrag_running) == 0)); 1217 if (flags & SB_RDONLY) 1218 sync_filesystem(fs_info->sb); 1219 } 1220 } 1221 1222 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info, 1223 unsigned long old_opts) 1224 { 1225 const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE); 1226 1227 /* 1228 * We need to cleanup all defragable inodes if the autodefragment is 1229 * close or the filesystem is read only. 1230 */ 1231 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) && 1232 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) { 1233 btrfs_cleanup_defrag_inodes(fs_info); 1234 } 1235 1236 /* If we toggled discard async */ 1237 if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) && 1238 btrfs_test_opt(fs_info, DISCARD_ASYNC)) 1239 btrfs_discard_resume(fs_info); 1240 else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) && 1241 !btrfs_test_opt(fs_info, DISCARD_ASYNC)) 1242 btrfs_discard_cleanup(fs_info); 1243 1244 /* If we toggled space cache */ 1245 if (cache_opt != btrfs_free_space_cache_v1_active(fs_info)) 1246 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt); 1247 } 1248 1249 static int btrfs_remount_rw(struct btrfs_fs_info *fs_info) 1250 { 1251 int ret; 1252 1253 if (BTRFS_FS_ERROR(fs_info)) { 1254 btrfs_err(fs_info, 1255 "remounting read-write after error is not allowed"); 1256 return -EINVAL; 1257 } 1258 1259 if (fs_info->fs_devices->rw_devices == 0) 1260 return -EACCES; 1261 1262 if (!btrfs_check_rw_degradable(fs_info, NULL)) { 1263 btrfs_warn(fs_info, 1264 "too many missing devices, writable remount is not allowed"); 1265 return -EACCES; 1266 } 1267 1268 if (btrfs_super_log_root(fs_info->super_copy) != 0) { 1269 btrfs_warn(fs_info, 1270 "mount required to replay tree-log, cannot remount read-write"); 1271 return -EINVAL; 1272 } 1273 1274 /* 1275 * NOTE: when remounting with a change that does writes, don't put it 1276 * anywhere above this point, as we are not sure to be safe to write 1277 * until we pass the above checks. 1278 */ 1279 ret = btrfs_start_pre_rw_mount(fs_info); 1280 if (ret) 1281 return ret; 1282 1283 btrfs_clear_sb_rdonly(fs_info->sb); 1284 1285 set_bit(BTRFS_FS_OPEN, &fs_info->flags); 1286 1287 /* 1288 * If we've gone from readonly -> read-write, we need to get our 1289 * sync/async discard lists in the right state. 1290 */ 1291 btrfs_discard_resume(fs_info); 1292 1293 return 0; 1294 } 1295 1296 static int btrfs_remount_ro(struct btrfs_fs_info *fs_info) 1297 { 1298 /* 1299 * This also happens on 'umount -rf' or on shutdown, when the 1300 * filesystem is busy. 1301 */ 1302 cancel_work_sync(&fs_info->async_reclaim_work); 1303 cancel_work_sync(&fs_info->async_data_reclaim_work); 1304 1305 btrfs_discard_cleanup(fs_info); 1306 1307 /* Wait for the uuid_scan task to finish */ 1308 down(&fs_info->uuid_tree_rescan_sem); 1309 /* Avoid complains from lockdep et al. */ 1310 up(&fs_info->uuid_tree_rescan_sem); 1311 1312 btrfs_set_sb_rdonly(fs_info->sb); 1313 1314 /* 1315 * Setting SB_RDONLY will put the cleaner thread to sleep at the next 1316 * loop if it's already active. If it's already asleep, we'll leave 1317 * unused block groups on disk until we're mounted read-write again 1318 * unless we clean them up here. 1319 */ 1320 btrfs_delete_unused_bgs(fs_info); 1321 1322 /* 1323 * The cleaner task could be already running before we set the flag 1324 * BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock). We must make 1325 * sure that after we finish the remount, i.e. after we call 1326 * btrfs_commit_super(), the cleaner can no longer start a transaction 1327 * - either because it was dropping a dead root, running delayed iputs 1328 * or deleting an unused block group (the cleaner picked a block 1329 * group from the list of unused block groups before we were able to 1330 * in the previous call to btrfs_delete_unused_bgs()). 1331 */ 1332 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING, TASK_UNINTERRUPTIBLE); 1333 1334 /* 1335 * We've set the superblock to RO mode, so we might have made the 1336 * cleaner task sleep without running all pending delayed iputs. Go 1337 * through all the delayed iputs here, so that if an unmount happens 1338 * without remounting RW we don't end up at finishing close_ctree() 1339 * with a non-empty list of delayed iputs. 1340 */ 1341 btrfs_run_delayed_iputs(fs_info); 1342 1343 btrfs_dev_replace_suspend_for_unmount(fs_info); 1344 btrfs_scrub_cancel(fs_info); 1345 btrfs_pause_balance(fs_info); 1346 1347 /* 1348 * Pause the qgroup rescan worker if it is running. We don't want it to 1349 * be still running after we are in RO mode, as after that, by the time 1350 * we unmount, it might have left a transaction open, so we would leak 1351 * the transaction and/or crash. 1352 */ 1353 btrfs_qgroup_wait_for_completion(fs_info, false); 1354 1355 return btrfs_commit_super(fs_info); 1356 } 1357 1358 static void btrfs_ctx_to_info(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx) 1359 { 1360 fs_info->max_inline = ctx->max_inline; 1361 fs_info->commit_interval = ctx->commit_interval; 1362 fs_info->metadata_ratio = ctx->metadata_ratio; 1363 fs_info->thread_pool_size = ctx->thread_pool_size; 1364 fs_info->mount_opt = ctx->mount_opt; 1365 fs_info->compress_type = ctx->compress_type; 1366 fs_info->compress_level = ctx->compress_level; 1367 } 1368 1369 static void btrfs_info_to_ctx(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx) 1370 { 1371 ctx->max_inline = fs_info->max_inline; 1372 ctx->commit_interval = fs_info->commit_interval; 1373 ctx->metadata_ratio = fs_info->metadata_ratio; 1374 ctx->thread_pool_size = fs_info->thread_pool_size; 1375 ctx->mount_opt = fs_info->mount_opt; 1376 ctx->compress_type = fs_info->compress_type; 1377 ctx->compress_level = fs_info->compress_level; 1378 } 1379 1380 #define btrfs_info_if_set(fs_info, old_ctx, opt, fmt, args...) \ 1381 do { \ 1382 if ((!old_ctx || !btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \ 1383 btrfs_raw_test_opt(fs_info->mount_opt, opt)) \ 1384 btrfs_info(fs_info, fmt, ##args); \ 1385 } while (0) 1386 1387 #define btrfs_info_if_unset(fs_info, old_ctx, opt, fmt, args...) \ 1388 do { \ 1389 if ((old_ctx && btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \ 1390 !btrfs_raw_test_opt(fs_info->mount_opt, opt)) \ 1391 btrfs_info(fs_info, fmt, ##args); \ 1392 } while (0) 1393 1394 static void btrfs_emit_options(struct btrfs_fs_info *info, 1395 struct btrfs_fs_context *old) 1396 { 1397 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum"); 1398 btrfs_info_if_set(info, old, DEGRADED, "allowing degraded mounts"); 1399 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum"); 1400 btrfs_info_if_set(info, old, SSD, "enabling ssd optimizations"); 1401 btrfs_info_if_set(info, old, SSD_SPREAD, "using spread ssd allocation scheme"); 1402 btrfs_info_if_set(info, old, NOBARRIER, "turning off barriers"); 1403 btrfs_info_if_set(info, old, NOTREELOG, "disabling tree log"); 1404 btrfs_info_if_set(info, old, NOLOGREPLAY, "disabling log replay at mount time"); 1405 btrfs_info_if_set(info, old, FLUSHONCOMMIT, "turning on flush-on-commit"); 1406 btrfs_info_if_set(info, old, DISCARD_SYNC, "turning on sync discard"); 1407 btrfs_info_if_set(info, old, DISCARD_ASYNC, "turning on async discard"); 1408 btrfs_info_if_set(info, old, FREE_SPACE_TREE, "enabling free space tree"); 1409 btrfs_info_if_set(info, old, SPACE_CACHE, "enabling disk space caching"); 1410 btrfs_info_if_set(info, old, CLEAR_CACHE, "force clearing of disk cache"); 1411 btrfs_info_if_set(info, old, AUTO_DEFRAG, "enabling auto defrag"); 1412 btrfs_info_if_set(info, old, FRAGMENT_DATA, "fragmenting data"); 1413 btrfs_info_if_set(info, old, FRAGMENT_METADATA, "fragmenting metadata"); 1414 btrfs_info_if_set(info, old, REF_VERIFY, "doing ref verification"); 1415 btrfs_info_if_set(info, old, USEBACKUPROOT, "trying to use backup root at mount time"); 1416 btrfs_info_if_set(info, old, IGNOREBADROOTS, "ignoring bad roots"); 1417 btrfs_info_if_set(info, old, IGNOREDATACSUMS, "ignoring data csums"); 1418 1419 btrfs_info_if_unset(info, old, NODATACOW, "setting datacow"); 1420 btrfs_info_if_unset(info, old, SSD, "not using ssd optimizations"); 1421 btrfs_info_if_unset(info, old, SSD_SPREAD, "not using spread ssd allocation scheme"); 1422 btrfs_info_if_unset(info, old, NOBARRIER, "turning off barriers"); 1423 btrfs_info_if_unset(info, old, NOTREELOG, "enabling tree log"); 1424 btrfs_info_if_unset(info, old, SPACE_CACHE, "disabling disk space caching"); 1425 btrfs_info_if_unset(info, old, FREE_SPACE_TREE, "disabling free space tree"); 1426 btrfs_info_if_unset(info, old, AUTO_DEFRAG, "disabling auto defrag"); 1427 btrfs_info_if_unset(info, old, COMPRESS, "use no compression"); 1428 1429 /* Did the compression settings change? */ 1430 if (btrfs_test_opt(info, COMPRESS) && 1431 (!old || 1432 old->compress_type != info->compress_type || 1433 old->compress_level != info->compress_level || 1434 (!btrfs_raw_test_opt(old->mount_opt, FORCE_COMPRESS) && 1435 btrfs_raw_test_opt(info->mount_opt, FORCE_COMPRESS)))) { 1436 const char *compress_type = btrfs_compress_type2str(info->compress_type); 1437 1438 btrfs_info(info, "%s %s compression, level %d", 1439 btrfs_test_opt(info, FORCE_COMPRESS) ? "force" : "use", 1440 compress_type, info->compress_level); 1441 } 1442 1443 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE) 1444 btrfs_info(info, "max_inline set to %llu", info->max_inline); 1445 } 1446 1447 static int btrfs_reconfigure(struct fs_context *fc) 1448 { 1449 struct super_block *sb = fc->root->d_sb; 1450 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1451 struct btrfs_fs_context *ctx = fc->fs_private; 1452 struct btrfs_fs_context old_ctx; 1453 int ret = 0; 1454 bool mount_reconfigure = (fc->s_fs_info != NULL); 1455 1456 btrfs_info_to_ctx(fs_info, &old_ctx); 1457 1458 /* 1459 * This is our "bind mount" trick, we don't want to allow the user to do 1460 * anything other than mount a different ro/rw and a different subvol, 1461 * all of the mount options should be maintained. 1462 */ 1463 if (mount_reconfigure) 1464 ctx->mount_opt = old_ctx.mount_opt; 1465 1466 sync_filesystem(sb); 1467 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state); 1468 1469 if (!mount_reconfigure && 1470 !btrfs_check_options(fs_info, &ctx->mount_opt, fc->sb_flags)) 1471 return -EINVAL; 1472 1473 ret = btrfs_check_features(fs_info, !(fc->sb_flags & SB_RDONLY)); 1474 if (ret < 0) 1475 return ret; 1476 1477 btrfs_ctx_to_info(fs_info, ctx); 1478 btrfs_remount_begin(fs_info, old_ctx.mount_opt, fc->sb_flags); 1479 btrfs_resize_thread_pool(fs_info, fs_info->thread_pool_size, 1480 old_ctx.thread_pool_size); 1481 1482 if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) != 1483 (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) && 1484 (!sb_rdonly(sb) || (fc->sb_flags & SB_RDONLY))) { 1485 btrfs_warn(fs_info, 1486 "remount supports changing free space tree only from RO to RW"); 1487 /* Make sure free space cache options match the state on disk. */ 1488 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) { 1489 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE); 1490 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE); 1491 } 1492 if (btrfs_free_space_cache_v1_active(fs_info)) { 1493 btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE); 1494 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE); 1495 } 1496 } 1497 1498 ret = 0; 1499 if (!sb_rdonly(sb) && (fc->sb_flags & SB_RDONLY)) 1500 ret = btrfs_remount_ro(fs_info); 1501 else if (sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY)) 1502 ret = btrfs_remount_rw(fs_info); 1503 if (ret) 1504 goto restore; 1505 1506 /* 1507 * If we set the mask during the parameter parsing VFS would reject the 1508 * remount. Here we can set the mask and the value will be updated 1509 * appropriately. 1510 */ 1511 if ((fc->sb_flags & SB_POSIXACL) != (sb->s_flags & SB_POSIXACL)) 1512 fc->sb_flags_mask |= SB_POSIXACL; 1513 1514 btrfs_emit_options(fs_info, &old_ctx); 1515 wake_up_process(fs_info->transaction_kthread); 1516 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt); 1517 btrfs_clear_oneshot_options(fs_info); 1518 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state); 1519 1520 return 0; 1521 restore: 1522 btrfs_ctx_to_info(fs_info, &old_ctx); 1523 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt); 1524 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state); 1525 return ret; 1526 } 1527 1528 /* Used to sort the devices by max_avail(descending sort) */ 1529 static int btrfs_cmp_device_free_bytes(const void *a, const void *b) 1530 { 1531 const struct btrfs_device_info *dev_info1 = a; 1532 const struct btrfs_device_info *dev_info2 = b; 1533 1534 if (dev_info1->max_avail > dev_info2->max_avail) 1535 return -1; 1536 else if (dev_info1->max_avail < dev_info2->max_avail) 1537 return 1; 1538 return 0; 1539 } 1540 1541 /* 1542 * sort the devices by max_avail, in which max free extent size of each device 1543 * is stored.(Descending Sort) 1544 */ 1545 static inline void btrfs_descending_sort_devices( 1546 struct btrfs_device_info *devices, 1547 size_t nr_devices) 1548 { 1549 sort(devices, nr_devices, sizeof(struct btrfs_device_info), 1550 btrfs_cmp_device_free_bytes, NULL); 1551 } 1552 1553 /* 1554 * The helper to calc the free space on the devices that can be used to store 1555 * file data. 1556 */ 1557 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info, 1558 u64 *free_bytes) 1559 { 1560 struct btrfs_device_info *devices_info; 1561 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; 1562 struct btrfs_device *device; 1563 u64 type; 1564 u64 avail_space; 1565 u64 min_stripe_size; 1566 int num_stripes = 1; 1567 int i = 0, nr_devices; 1568 const struct btrfs_raid_attr *rattr; 1569 1570 /* 1571 * We aren't under the device list lock, so this is racy-ish, but good 1572 * enough for our purposes. 1573 */ 1574 nr_devices = fs_info->fs_devices->open_devices; 1575 if (!nr_devices) { 1576 smp_mb(); 1577 nr_devices = fs_info->fs_devices->open_devices; 1578 ASSERT(nr_devices); 1579 if (!nr_devices) { 1580 *free_bytes = 0; 1581 return 0; 1582 } 1583 } 1584 1585 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info), 1586 GFP_KERNEL); 1587 if (!devices_info) 1588 return -ENOMEM; 1589 1590 /* calc min stripe number for data space allocation */ 1591 type = btrfs_data_alloc_profile(fs_info); 1592 rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)]; 1593 1594 if (type & BTRFS_BLOCK_GROUP_RAID0) 1595 num_stripes = nr_devices; 1596 else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK) 1597 num_stripes = rattr->ncopies; 1598 else if (type & BTRFS_BLOCK_GROUP_RAID10) 1599 num_stripes = 4; 1600 1601 /* Adjust for more than 1 stripe per device */ 1602 min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN; 1603 1604 rcu_read_lock(); 1605 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) { 1606 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, 1607 &device->dev_state) || 1608 !device->bdev || 1609 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) 1610 continue; 1611 1612 if (i >= nr_devices) 1613 break; 1614 1615 avail_space = device->total_bytes - device->bytes_used; 1616 1617 /* align with stripe_len */ 1618 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN); 1619 1620 /* 1621 * Ensure we have at least min_stripe_size on top of the 1622 * reserved space on the device. 1623 */ 1624 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size) 1625 continue; 1626 1627 avail_space -= BTRFS_DEVICE_RANGE_RESERVED; 1628 1629 devices_info[i].dev = device; 1630 devices_info[i].max_avail = avail_space; 1631 1632 i++; 1633 } 1634 rcu_read_unlock(); 1635 1636 nr_devices = i; 1637 1638 btrfs_descending_sort_devices(devices_info, nr_devices); 1639 1640 i = nr_devices - 1; 1641 avail_space = 0; 1642 while (nr_devices >= rattr->devs_min) { 1643 num_stripes = min(num_stripes, nr_devices); 1644 1645 if (devices_info[i].max_avail >= min_stripe_size) { 1646 int j; 1647 u64 alloc_size; 1648 1649 avail_space += devices_info[i].max_avail * num_stripes; 1650 alloc_size = devices_info[i].max_avail; 1651 for (j = i + 1 - num_stripes; j <= i; j++) 1652 devices_info[j].max_avail -= alloc_size; 1653 } 1654 i--; 1655 nr_devices--; 1656 } 1657 1658 kfree(devices_info); 1659 *free_bytes = avail_space; 1660 return 0; 1661 } 1662 1663 /* 1664 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles. 1665 * 1666 * If there's a redundant raid level at DATA block groups, use the respective 1667 * multiplier to scale the sizes. 1668 * 1669 * Unused device space usage is based on simulating the chunk allocator 1670 * algorithm that respects the device sizes and order of allocations. This is 1671 * a close approximation of the actual use but there are other factors that may 1672 * change the result (like a new metadata chunk). 1673 * 1674 * If metadata is exhausted, f_bavail will be 0. 1675 */ 1676 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 1677 { 1678 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb); 1679 struct btrfs_super_block *disk_super = fs_info->super_copy; 1680 struct btrfs_space_info *found; 1681 u64 total_used = 0; 1682 u64 total_free_data = 0; 1683 u64 total_free_meta = 0; 1684 u32 bits = fs_info->sectorsize_bits; 1685 __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid; 1686 unsigned factor = 1; 1687 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv; 1688 int ret; 1689 u64 thresh = 0; 1690 int mixed = 0; 1691 1692 list_for_each_entry(found, &fs_info->space_info, list) { 1693 if (found->flags & BTRFS_BLOCK_GROUP_DATA) { 1694 int i; 1695 1696 total_free_data += found->disk_total - found->disk_used; 1697 total_free_data -= 1698 btrfs_account_ro_block_groups_free_space(found); 1699 1700 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) { 1701 if (!list_empty(&found->block_groups[i])) 1702 factor = btrfs_bg_type_to_factor( 1703 btrfs_raid_array[i].bg_flag); 1704 } 1705 } 1706 1707 /* 1708 * Metadata in mixed block group profiles are accounted in data 1709 */ 1710 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) { 1711 if (found->flags & BTRFS_BLOCK_GROUP_DATA) 1712 mixed = 1; 1713 else 1714 total_free_meta += found->disk_total - 1715 found->disk_used; 1716 } 1717 1718 total_used += found->disk_used; 1719 } 1720 1721 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor); 1722 buf->f_blocks >>= bits; 1723 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits); 1724 1725 /* Account global block reserve as used, it's in logical size already */ 1726 spin_lock(&block_rsv->lock); 1727 /* Mixed block groups accounting is not byte-accurate, avoid overflow */ 1728 if (buf->f_bfree >= block_rsv->size >> bits) 1729 buf->f_bfree -= block_rsv->size >> bits; 1730 else 1731 buf->f_bfree = 0; 1732 spin_unlock(&block_rsv->lock); 1733 1734 buf->f_bavail = div_u64(total_free_data, factor); 1735 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data); 1736 if (ret) 1737 return ret; 1738 buf->f_bavail += div_u64(total_free_data, factor); 1739 buf->f_bavail = buf->f_bavail >> bits; 1740 1741 /* 1742 * We calculate the remaining metadata space minus global reserve. If 1743 * this is (supposedly) smaller than zero, there's no space. But this 1744 * does not hold in practice, the exhausted state happens where's still 1745 * some positive delta. So we apply some guesswork and compare the 1746 * delta to a 4M threshold. (Practically observed delta was ~2M.) 1747 * 1748 * We probably cannot calculate the exact threshold value because this 1749 * depends on the internal reservations requested by various 1750 * operations, so some operations that consume a few metadata will 1751 * succeed even if the Avail is zero. But this is better than the other 1752 * way around. 1753 */ 1754 thresh = SZ_4M; 1755 1756 /* 1757 * We only want to claim there's no available space if we can no longer 1758 * allocate chunks for our metadata profile and our global reserve will 1759 * not fit in the free metadata space. If we aren't ->full then we 1760 * still can allocate chunks and thus are fine using the currently 1761 * calculated f_bavail. 1762 */ 1763 if (!mixed && block_rsv->space_info->full && 1764 (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size)) 1765 buf->f_bavail = 0; 1766 1767 buf->f_type = BTRFS_SUPER_MAGIC; 1768 buf->f_bsize = fs_info->sectorsize; 1769 buf->f_namelen = BTRFS_NAME_LEN; 1770 1771 /* We treat it as constant endianness (it doesn't matter _which_) 1772 because we want the fsid to come out the same whether mounted 1773 on a big-endian or little-endian host */ 1774 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]); 1775 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]); 1776 /* Mask in the root object ID too, to disambiguate subvols */ 1777 buf->f_fsid.val[0] ^= 1778 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32; 1779 buf->f_fsid.val[1] ^= 1780 BTRFS_I(d_inode(dentry))->root->root_key.objectid; 1781 1782 return 0; 1783 } 1784 1785 static int btrfs_fc_test_super(struct super_block *sb, struct fs_context *fc) 1786 { 1787 struct btrfs_fs_info *p = fc->s_fs_info; 1788 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 1789 1790 return fs_info->fs_devices == p->fs_devices; 1791 } 1792 1793 static int btrfs_get_tree_super(struct fs_context *fc) 1794 { 1795 struct btrfs_fs_info *fs_info = fc->s_fs_info; 1796 struct btrfs_fs_context *ctx = fc->fs_private; 1797 struct btrfs_fs_devices *fs_devices = NULL; 1798 struct block_device *bdev; 1799 struct btrfs_device *device; 1800 struct super_block *sb; 1801 blk_mode_t mode = btrfs_open_mode(fc); 1802 int ret; 1803 1804 btrfs_ctx_to_info(fs_info, ctx); 1805 mutex_lock(&uuid_mutex); 1806 1807 /* 1808 * With 'true' passed to btrfs_scan_one_device() (mount time) we expect 1809 * either a valid device or an error. 1810 */ 1811 device = btrfs_scan_one_device(fc->source, mode, true); 1812 ASSERT(device != NULL); 1813 if (IS_ERR(device)) { 1814 mutex_unlock(&uuid_mutex); 1815 return PTR_ERR(device); 1816 } 1817 1818 fs_devices = device->fs_devices; 1819 fs_info->fs_devices = fs_devices; 1820 1821 ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type); 1822 mutex_unlock(&uuid_mutex); 1823 if (ret) 1824 return ret; 1825 1826 if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) { 1827 ret = -EACCES; 1828 goto error; 1829 } 1830 1831 bdev = fs_devices->latest_dev->bdev; 1832 1833 /* 1834 * From now on the error handling is not straightforward. 1835 * 1836 * If successful, this will transfer the fs_info into the super block, 1837 * and fc->s_fs_info will be NULL. However if there's an existing 1838 * super, we'll still have fc->s_fs_info populated. If we error 1839 * completely out it'll be cleaned up when we drop the fs_context, 1840 * otherwise it's tied to the lifetime of the super_block. 1841 */ 1842 sb = sget_fc(fc, btrfs_fc_test_super, set_anon_super_fc); 1843 if (IS_ERR(sb)) { 1844 ret = PTR_ERR(sb); 1845 goto error; 1846 } 1847 1848 set_device_specific_options(fs_info); 1849 1850 if (sb->s_root) { 1851 btrfs_close_devices(fs_devices); 1852 if ((fc->sb_flags ^ sb->s_flags) & SB_RDONLY) 1853 ret = -EBUSY; 1854 } else { 1855 snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev); 1856 shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id); 1857 btrfs_sb(sb)->bdev_holder = &btrfs_fs_type; 1858 ret = btrfs_fill_super(sb, fs_devices, NULL); 1859 } 1860 1861 if (ret) { 1862 deactivate_locked_super(sb); 1863 return ret; 1864 } 1865 1866 btrfs_clear_oneshot_options(fs_info); 1867 1868 fc->root = dget(sb->s_root); 1869 return 0; 1870 1871 error: 1872 btrfs_close_devices(fs_devices); 1873 return ret; 1874 } 1875 1876 /* 1877 * Ever since commit 0723a0473fb4 ("btrfs: allow mounting btrfs subvolumes 1878 * with different ro/rw options") the following works: 1879 * 1880 * (i) mount /dev/sda3 -o subvol=foo,ro /mnt/foo 1881 * (ii) mount /dev/sda3 -o subvol=bar,rw /mnt/bar 1882 * 1883 * which looks nice and innocent but is actually pretty intricate and deserves 1884 * a long comment. 1885 * 1886 * On another filesystem a subvolume mount is close to something like: 1887 * 1888 * (iii) # create rw superblock + initial mount 1889 * mount -t xfs /dev/sdb /opt/ 1890 * 1891 * # create ro bind mount 1892 * mount --bind -o ro /opt/foo /mnt/foo 1893 * 1894 * # unmount initial mount 1895 * umount /opt 1896 * 1897 * Of course, there's some special subvolume sauce and there's the fact that the 1898 * sb->s_root dentry is really swapped after mount_subtree(). But conceptually 1899 * it's very close and will help us understand the issue. 1900 * 1901 * The old mount API didn't cleanly distinguish between a mount being made ro 1902 * and a superblock being made ro. The only way to change the ro state of 1903 * either object was by passing ms_rdonly. If a new mount was created via 1904 * mount(2) such as: 1905 * 1906 * mount("/dev/sdb", "/mnt", "xfs", ms_rdonly, null); 1907 * 1908 * the MS_RDONLY flag being specified had two effects: 1909 * 1910 * (1) MNT_READONLY was raised -> the resulting mount got 1911 * @mnt->mnt_flags |= MNT_READONLY raised. 1912 * 1913 * (2) MS_RDONLY was passed to the filesystem's mount method and the filesystems 1914 * made the superblock ro. Note, how SB_RDONLY has the same value as 1915 * ms_rdonly and is raised whenever MS_RDONLY is passed through mount(2). 1916 * 1917 * Creating a subtree mount via (iii) ends up leaving a rw superblock with a 1918 * subtree mounted ro. 1919 * 1920 * But consider the effect on the old mount API on btrfs subvolume mounting 1921 * which combines the distinct step in (iii) into a single step. 1922 * 1923 * By issuing (i) both the mount and the superblock are turned ro. Now when (ii) 1924 * is issued the superblock is ro and thus even if the mount created for (ii) is 1925 * rw it wouldn't help. Hence, btrfs needed to transition the superblock from ro 1926 * to rw for (ii) which it did using an internal remount call. 1927 * 1928 * IOW, subvolume mounting was inherently complicated due to the ambiguity of 1929 * MS_RDONLY in mount(2). Note, this ambiguity has mount(8) always translate 1930 * "ro" to MS_RDONLY. IOW, in both (i) and (ii) "ro" becomes MS_RDONLY when 1931 * passed by mount(8) to mount(2). 1932 * 1933 * Enter the new mount API. The new mount API disambiguates making a mount ro 1934 * and making a superblock ro. 1935 * 1936 * (3) To turn a mount ro the MOUNT_ATTR_ONLY flag can be used with either 1937 * fsmount() or mount_setattr() this is a pure VFS level change for a 1938 * specific mount or mount tree that is never seen by the filesystem itself. 1939 * 1940 * (4) To turn a superblock ro the "ro" flag must be used with 1941 * fsconfig(FSCONFIG_SET_FLAG, "ro"). This option is seen by the filesystem 1942 * in fc->sb_flags. 1943 * 1944 * This disambiguation has rather positive consequences. Mounting a subvolume 1945 * ro will not also turn the superblock ro. Only the mount for the subvolume 1946 * will become ro. 1947 * 1948 * So, if the superblock creation request comes from the new mount API the 1949 * caller must have explicitly done: 1950 * 1951 * fsconfig(FSCONFIG_SET_FLAG, "ro") 1952 * fsmount/mount_setattr(MOUNT_ATTR_RDONLY) 1953 * 1954 * IOW, at some point the caller must have explicitly turned the whole 1955 * superblock ro and we shouldn't just undo it like we did for the old mount 1956 * API. In any case, it lets us avoid the hack in the new mount API. 1957 * 1958 * Consequently, the remounting hack must only be used for requests originating 1959 * from the old mount API and should be marked for full deprecation so it can be 1960 * turned off in a couple of years. 1961 * 1962 * The new mount API has no reason to support this hack. 1963 */ 1964 static struct vfsmount *btrfs_reconfigure_for_mount(struct fs_context *fc) 1965 { 1966 struct vfsmount *mnt; 1967 int ret; 1968 const bool ro2rw = !(fc->sb_flags & SB_RDONLY); 1969 1970 /* 1971 * We got an EBUSY because our SB_RDONLY flag didn't match the existing 1972 * super block, so invert our setting here and retry the mount so we 1973 * can get our vfsmount. 1974 */ 1975 if (ro2rw) 1976 fc->sb_flags |= SB_RDONLY; 1977 else 1978 fc->sb_flags &= ~SB_RDONLY; 1979 1980 mnt = fc_mount(fc); 1981 if (IS_ERR(mnt)) 1982 return mnt; 1983 1984 if (!fc->oldapi || !ro2rw) 1985 return mnt; 1986 1987 /* We need to convert to rw, call reconfigure. */ 1988 fc->sb_flags &= ~SB_RDONLY; 1989 down_write(&mnt->mnt_sb->s_umount); 1990 ret = btrfs_reconfigure(fc); 1991 up_write(&mnt->mnt_sb->s_umount); 1992 if (ret) { 1993 mntput(mnt); 1994 return ERR_PTR(ret); 1995 } 1996 return mnt; 1997 } 1998 1999 static int btrfs_get_tree_subvol(struct fs_context *fc) 2000 { 2001 struct btrfs_fs_info *fs_info = NULL; 2002 struct btrfs_fs_context *ctx = fc->fs_private; 2003 struct fs_context *dup_fc; 2004 struct dentry *dentry; 2005 struct vfsmount *mnt; 2006 2007 /* 2008 * Setup a dummy root and fs_info for test/set super. This is because 2009 * we don't actually fill this stuff out until open_ctree, but we need 2010 * then open_ctree will properly initialize the file system specific 2011 * settings later. btrfs_init_fs_info initializes the static elements 2012 * of the fs_info (locks and such) to make cleanup easier if we find a 2013 * superblock with our given fs_devices later on at sget() time. 2014 */ 2015 fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL); 2016 if (!fs_info) 2017 return -ENOMEM; 2018 2019 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL); 2020 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL); 2021 if (!fs_info->super_copy || !fs_info->super_for_commit) { 2022 btrfs_free_fs_info(fs_info); 2023 return -ENOMEM; 2024 } 2025 btrfs_init_fs_info(fs_info); 2026 2027 dup_fc = vfs_dup_fs_context(fc); 2028 if (IS_ERR(dup_fc)) { 2029 btrfs_free_fs_info(fs_info); 2030 return PTR_ERR(dup_fc); 2031 } 2032 2033 /* 2034 * When we do the sget_fc this gets transferred to the sb, so we only 2035 * need to set it on the dup_fc as this is what creates the super block. 2036 */ 2037 dup_fc->s_fs_info = fs_info; 2038 2039 /* 2040 * We'll do the security settings in our btrfs_get_tree_super() mount 2041 * loop, they were duplicated into dup_fc, we can drop the originals 2042 * here. 2043 */ 2044 security_free_mnt_opts(&fc->security); 2045 fc->security = NULL; 2046 2047 mnt = fc_mount(dup_fc); 2048 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) 2049 mnt = btrfs_reconfigure_for_mount(dup_fc); 2050 put_fs_context(dup_fc); 2051 if (IS_ERR(mnt)) 2052 return PTR_ERR(mnt); 2053 2054 /* 2055 * This free's ->subvol_name, because if it isn't set we have to 2056 * allocate a buffer to hold the subvol_name, so we just drop our 2057 * reference to it here. 2058 */ 2059 dentry = mount_subvol(ctx->subvol_name, ctx->subvol_objectid, mnt); 2060 ctx->subvol_name = NULL; 2061 if (IS_ERR(dentry)) 2062 return PTR_ERR(dentry); 2063 2064 fc->root = dentry; 2065 return 0; 2066 } 2067 2068 static int btrfs_get_tree(struct fs_context *fc) 2069 { 2070 /* 2071 * Since we use mount_subtree to mount the default/specified subvol, we 2072 * have to do mounts in two steps. 2073 * 2074 * First pass through we call btrfs_get_tree_subvol(), this is just a 2075 * wrapper around fc_mount() to call back into here again, and this time 2076 * we'll call btrfs_get_tree_super(). This will do the open_ctree() and 2077 * everything to open the devices and file system. Then we return back 2078 * with a fully constructed vfsmount in btrfs_get_tree_subvol(), and 2079 * from there we can do our mount_subvol() call, which will lookup 2080 * whichever subvol we're mounting and setup this fc with the 2081 * appropriate dentry for the subvol. 2082 */ 2083 if (fc->s_fs_info) 2084 return btrfs_get_tree_super(fc); 2085 return btrfs_get_tree_subvol(fc); 2086 } 2087 2088 static void btrfs_kill_super(struct super_block *sb) 2089 { 2090 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 2091 kill_anon_super(sb); 2092 btrfs_free_fs_info(fs_info); 2093 } 2094 2095 static void btrfs_free_fs_context(struct fs_context *fc) 2096 { 2097 struct btrfs_fs_context *ctx = fc->fs_private; 2098 struct btrfs_fs_info *fs_info = fc->s_fs_info; 2099 2100 if (fs_info) 2101 btrfs_free_fs_info(fs_info); 2102 2103 if (ctx && refcount_dec_and_test(&ctx->refs)) { 2104 kfree(ctx->subvol_name); 2105 kfree(ctx); 2106 } 2107 } 2108 2109 static int btrfs_dup_fs_context(struct fs_context *fc, struct fs_context *src_fc) 2110 { 2111 struct btrfs_fs_context *ctx = src_fc->fs_private; 2112 2113 /* 2114 * Give a ref to our ctx to this dup, as we want to keep it around for 2115 * our original fc so we can have the subvolume name or objectid. 2116 * 2117 * We unset ->source in the original fc because the dup needs it for 2118 * mounting, and then once we free the dup it'll free ->source, so we 2119 * need to make sure we're only pointing to it in one fc. 2120 */ 2121 refcount_inc(&ctx->refs); 2122 fc->fs_private = ctx; 2123 fc->source = src_fc->source; 2124 src_fc->source = NULL; 2125 return 0; 2126 } 2127 2128 static const struct fs_context_operations btrfs_fs_context_ops = { 2129 .parse_param = btrfs_parse_param, 2130 .reconfigure = btrfs_reconfigure, 2131 .get_tree = btrfs_get_tree, 2132 .dup = btrfs_dup_fs_context, 2133 .free = btrfs_free_fs_context, 2134 }; 2135 2136 static int btrfs_init_fs_context(struct fs_context *fc) 2137 { 2138 struct btrfs_fs_context *ctx; 2139 2140 ctx = kzalloc(sizeof(struct btrfs_fs_context), GFP_KERNEL); 2141 if (!ctx) 2142 return -ENOMEM; 2143 2144 refcount_set(&ctx->refs, 1); 2145 fc->fs_private = ctx; 2146 fc->ops = &btrfs_fs_context_ops; 2147 2148 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { 2149 btrfs_info_to_ctx(btrfs_sb(fc->root->d_sb), ctx); 2150 } else { 2151 ctx->thread_pool_size = 2152 min_t(unsigned long, num_online_cpus() + 2, 8); 2153 ctx->max_inline = BTRFS_DEFAULT_MAX_INLINE; 2154 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL; 2155 } 2156 2157 #ifdef CONFIG_BTRFS_FS_POSIX_ACL 2158 fc->sb_flags |= SB_POSIXACL; 2159 #endif 2160 fc->sb_flags |= SB_I_VERSION; 2161 2162 return 0; 2163 } 2164 2165 static struct file_system_type btrfs_fs_type = { 2166 .owner = THIS_MODULE, 2167 .name = "btrfs", 2168 .init_fs_context = btrfs_init_fs_context, 2169 .parameters = btrfs_fs_parameters, 2170 .kill_sb = btrfs_kill_super, 2171 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP, 2172 }; 2173 2174 MODULE_ALIAS_FS("btrfs"); 2175 2176 static int btrfs_control_open(struct inode *inode, struct file *file) 2177 { 2178 /* 2179 * The control file's private_data is used to hold the 2180 * transaction when it is started and is used to keep 2181 * track of whether a transaction is already in progress. 2182 */ 2183 file->private_data = NULL; 2184 return 0; 2185 } 2186 2187 /* 2188 * Used by /dev/btrfs-control for devices ioctls. 2189 */ 2190 static long btrfs_control_ioctl(struct file *file, unsigned int cmd, 2191 unsigned long arg) 2192 { 2193 struct btrfs_ioctl_vol_args *vol; 2194 struct btrfs_device *device = NULL; 2195 dev_t devt = 0; 2196 int ret = -ENOTTY; 2197 2198 if (!capable(CAP_SYS_ADMIN)) 2199 return -EPERM; 2200 2201 vol = memdup_user((void __user *)arg, sizeof(*vol)); 2202 if (IS_ERR(vol)) 2203 return PTR_ERR(vol); 2204 ret = btrfs_check_ioctl_vol_args_path(vol); 2205 if (ret < 0) 2206 goto out; 2207 2208 switch (cmd) { 2209 case BTRFS_IOC_SCAN_DEV: 2210 mutex_lock(&uuid_mutex); 2211 /* 2212 * Scanning outside of mount can return NULL which would turn 2213 * into 0 error code. 2214 */ 2215 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false); 2216 ret = PTR_ERR_OR_ZERO(device); 2217 mutex_unlock(&uuid_mutex); 2218 break; 2219 case BTRFS_IOC_FORGET_DEV: 2220 if (vol->name[0] != 0) { 2221 ret = lookup_bdev(vol->name, &devt); 2222 if (ret) 2223 break; 2224 } 2225 ret = btrfs_forget_devices(devt); 2226 break; 2227 case BTRFS_IOC_DEVICES_READY: 2228 mutex_lock(&uuid_mutex); 2229 /* 2230 * Scanning outside of mount can return NULL which would turn 2231 * into 0 error code. 2232 */ 2233 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false); 2234 if (IS_ERR_OR_NULL(device)) { 2235 mutex_unlock(&uuid_mutex); 2236 ret = PTR_ERR(device); 2237 break; 2238 } 2239 ret = !(device->fs_devices->num_devices == 2240 device->fs_devices->total_devices); 2241 mutex_unlock(&uuid_mutex); 2242 break; 2243 case BTRFS_IOC_GET_SUPPORTED_FEATURES: 2244 ret = btrfs_ioctl_get_supported_features((void __user*)arg); 2245 break; 2246 } 2247 2248 out: 2249 kfree(vol); 2250 return ret; 2251 } 2252 2253 static int btrfs_freeze(struct super_block *sb) 2254 { 2255 struct btrfs_trans_handle *trans; 2256 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 2257 struct btrfs_root *root = fs_info->tree_root; 2258 2259 set_bit(BTRFS_FS_FROZEN, &fs_info->flags); 2260 /* 2261 * We don't need a barrier here, we'll wait for any transaction that 2262 * could be in progress on other threads (and do delayed iputs that 2263 * we want to avoid on a frozen filesystem), or do the commit 2264 * ourselves. 2265 */ 2266 trans = btrfs_attach_transaction_barrier(root); 2267 if (IS_ERR(trans)) { 2268 /* no transaction, don't bother */ 2269 if (PTR_ERR(trans) == -ENOENT) 2270 return 0; 2271 return PTR_ERR(trans); 2272 } 2273 return btrfs_commit_transaction(trans); 2274 } 2275 2276 static int check_dev_super(struct btrfs_device *dev) 2277 { 2278 struct btrfs_fs_info *fs_info = dev->fs_info; 2279 struct btrfs_super_block *sb; 2280 u64 last_trans; 2281 u16 csum_type; 2282 int ret = 0; 2283 2284 /* This should be called with fs still frozen. */ 2285 ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags)); 2286 2287 /* Missing dev, no need to check. */ 2288 if (!dev->bdev) 2289 return 0; 2290 2291 /* Only need to check the primary super block. */ 2292 sb = btrfs_read_dev_one_super(dev->bdev, 0, true); 2293 if (IS_ERR(sb)) 2294 return PTR_ERR(sb); 2295 2296 /* Verify the checksum. */ 2297 csum_type = btrfs_super_csum_type(sb); 2298 if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) { 2299 btrfs_err(fs_info, "csum type changed, has %u expect %u", 2300 csum_type, btrfs_super_csum_type(fs_info->super_copy)); 2301 ret = -EUCLEAN; 2302 goto out; 2303 } 2304 2305 if (btrfs_check_super_csum(fs_info, sb)) { 2306 btrfs_err(fs_info, "csum for on-disk super block no longer matches"); 2307 ret = -EUCLEAN; 2308 goto out; 2309 } 2310 2311 /* Btrfs_validate_super() includes fsid check against super->fsid. */ 2312 ret = btrfs_validate_super(fs_info, sb, 0); 2313 if (ret < 0) 2314 goto out; 2315 2316 last_trans = btrfs_get_last_trans_committed(fs_info); 2317 if (btrfs_super_generation(sb) != last_trans) { 2318 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu", 2319 btrfs_super_generation(sb), last_trans); 2320 ret = -EUCLEAN; 2321 goto out; 2322 } 2323 out: 2324 btrfs_release_disk_super(sb); 2325 return ret; 2326 } 2327 2328 static int btrfs_unfreeze(struct super_block *sb) 2329 { 2330 struct btrfs_fs_info *fs_info = btrfs_sb(sb); 2331 struct btrfs_device *device; 2332 int ret = 0; 2333 2334 /* 2335 * Make sure the fs is not changed by accident (like hibernation then 2336 * modified by other OS). 2337 * If we found anything wrong, we mark the fs error immediately. 2338 * 2339 * And since the fs is frozen, no one can modify the fs yet, thus 2340 * we don't need to hold device_list_mutex. 2341 */ 2342 list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) { 2343 ret = check_dev_super(device); 2344 if (ret < 0) { 2345 btrfs_handle_fs_error(fs_info, ret, 2346 "super block on devid %llu got modified unexpectedly", 2347 device->devid); 2348 break; 2349 } 2350 } 2351 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags); 2352 2353 /* 2354 * We still return 0, to allow VFS layer to unfreeze the fs even the 2355 * above checks failed. Since the fs is either fine or read-only, we're 2356 * safe to continue, without causing further damage. 2357 */ 2358 return 0; 2359 } 2360 2361 static int btrfs_show_devname(struct seq_file *m, struct dentry *root) 2362 { 2363 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb); 2364 2365 /* 2366 * There should be always a valid pointer in latest_dev, it may be stale 2367 * for a short moment in case it's being deleted but still valid until 2368 * the end of RCU grace period. 2369 */ 2370 rcu_read_lock(); 2371 seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\"); 2372 rcu_read_unlock(); 2373 2374 return 0; 2375 } 2376 2377 static const struct super_operations btrfs_super_ops = { 2378 .drop_inode = btrfs_drop_inode, 2379 .evict_inode = btrfs_evict_inode, 2380 .put_super = btrfs_put_super, 2381 .sync_fs = btrfs_sync_fs, 2382 .show_options = btrfs_show_options, 2383 .show_devname = btrfs_show_devname, 2384 .alloc_inode = btrfs_alloc_inode, 2385 .destroy_inode = btrfs_destroy_inode, 2386 .free_inode = btrfs_free_inode, 2387 .statfs = btrfs_statfs, 2388 .freeze_fs = btrfs_freeze, 2389 .unfreeze_fs = btrfs_unfreeze, 2390 }; 2391 2392 static const struct file_operations btrfs_ctl_fops = { 2393 .open = btrfs_control_open, 2394 .unlocked_ioctl = btrfs_control_ioctl, 2395 .compat_ioctl = compat_ptr_ioctl, 2396 .owner = THIS_MODULE, 2397 .llseek = noop_llseek, 2398 }; 2399 2400 static struct miscdevice btrfs_misc = { 2401 .minor = BTRFS_MINOR, 2402 .name = "btrfs-control", 2403 .fops = &btrfs_ctl_fops 2404 }; 2405 2406 MODULE_ALIAS_MISCDEV(BTRFS_MINOR); 2407 MODULE_ALIAS("devname:btrfs-control"); 2408 2409 static int __init btrfs_interface_init(void) 2410 { 2411 return misc_register(&btrfs_misc); 2412 } 2413 2414 static __cold void btrfs_interface_exit(void) 2415 { 2416 misc_deregister(&btrfs_misc); 2417 } 2418 2419 static int __init btrfs_print_mod_info(void) 2420 { 2421 static const char options[] = "" 2422 #ifdef CONFIG_BTRFS_DEBUG 2423 ", debug=on" 2424 #endif 2425 #ifdef CONFIG_BTRFS_ASSERT 2426 ", assert=on" 2427 #endif 2428 #ifdef CONFIG_BTRFS_FS_REF_VERIFY 2429 ", ref-verify=on" 2430 #endif 2431 #ifdef CONFIG_BLK_DEV_ZONED 2432 ", zoned=yes" 2433 #else 2434 ", zoned=no" 2435 #endif 2436 #ifdef CONFIG_FS_VERITY 2437 ", fsverity=yes" 2438 #else 2439 ", fsverity=no" 2440 #endif 2441 ; 2442 pr_info("Btrfs loaded%s\n", options); 2443 return 0; 2444 } 2445 2446 static int register_btrfs(void) 2447 { 2448 return register_filesystem(&btrfs_fs_type); 2449 } 2450 2451 static void unregister_btrfs(void) 2452 { 2453 unregister_filesystem(&btrfs_fs_type); 2454 } 2455 2456 /* Helper structure for long init/exit functions. */ 2457 struct init_sequence { 2458 int (*init_func)(void); 2459 /* Can be NULL if the init_func doesn't need cleanup. */ 2460 void (*exit_func)(void); 2461 }; 2462 2463 static const struct init_sequence mod_init_seq[] = { 2464 { 2465 .init_func = btrfs_props_init, 2466 .exit_func = NULL, 2467 }, { 2468 .init_func = btrfs_init_sysfs, 2469 .exit_func = btrfs_exit_sysfs, 2470 }, { 2471 .init_func = btrfs_init_compress, 2472 .exit_func = btrfs_exit_compress, 2473 }, { 2474 .init_func = btrfs_init_cachep, 2475 .exit_func = btrfs_destroy_cachep, 2476 }, { 2477 .init_func = btrfs_transaction_init, 2478 .exit_func = btrfs_transaction_exit, 2479 }, { 2480 .init_func = btrfs_ctree_init, 2481 .exit_func = btrfs_ctree_exit, 2482 }, { 2483 .init_func = btrfs_free_space_init, 2484 .exit_func = btrfs_free_space_exit, 2485 }, { 2486 .init_func = extent_state_init_cachep, 2487 .exit_func = extent_state_free_cachep, 2488 }, { 2489 .init_func = extent_buffer_init_cachep, 2490 .exit_func = extent_buffer_free_cachep, 2491 }, { 2492 .init_func = btrfs_bioset_init, 2493 .exit_func = btrfs_bioset_exit, 2494 }, { 2495 .init_func = extent_map_init, 2496 .exit_func = extent_map_exit, 2497 }, { 2498 .init_func = ordered_data_init, 2499 .exit_func = ordered_data_exit, 2500 }, { 2501 .init_func = btrfs_delayed_inode_init, 2502 .exit_func = btrfs_delayed_inode_exit, 2503 }, { 2504 .init_func = btrfs_auto_defrag_init, 2505 .exit_func = btrfs_auto_defrag_exit, 2506 }, { 2507 .init_func = btrfs_delayed_ref_init, 2508 .exit_func = btrfs_delayed_ref_exit, 2509 }, { 2510 .init_func = btrfs_prelim_ref_init, 2511 .exit_func = btrfs_prelim_ref_exit, 2512 }, { 2513 .init_func = btrfs_interface_init, 2514 .exit_func = btrfs_interface_exit, 2515 }, { 2516 .init_func = btrfs_print_mod_info, 2517 .exit_func = NULL, 2518 }, { 2519 .init_func = btrfs_run_sanity_tests, 2520 .exit_func = NULL, 2521 }, { 2522 .init_func = register_btrfs, 2523 .exit_func = unregister_btrfs, 2524 } 2525 }; 2526 2527 static bool mod_init_result[ARRAY_SIZE(mod_init_seq)]; 2528 2529 static __always_inline void btrfs_exit_btrfs_fs(void) 2530 { 2531 int i; 2532 2533 for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) { 2534 if (!mod_init_result[i]) 2535 continue; 2536 if (mod_init_seq[i].exit_func) 2537 mod_init_seq[i].exit_func(); 2538 mod_init_result[i] = false; 2539 } 2540 } 2541 2542 static void __exit exit_btrfs_fs(void) 2543 { 2544 btrfs_exit_btrfs_fs(); 2545 btrfs_cleanup_fs_uuids(); 2546 } 2547 2548 static int __init init_btrfs_fs(void) 2549 { 2550 int ret; 2551 int i; 2552 2553 for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) { 2554 ASSERT(!mod_init_result[i]); 2555 ret = mod_init_seq[i].init_func(); 2556 if (ret < 0) { 2557 btrfs_exit_btrfs_fs(); 2558 return ret; 2559 } 2560 mod_init_result[i] = true; 2561 } 2562 return 0; 2563 } 2564 2565 late_initcall(init_btrfs_fs); 2566 module_exit(exit_btrfs_fs) 2567 2568 MODULE_LICENSE("GPL"); 2569 MODULE_SOFTDEP("pre: crc32c"); 2570 MODULE_SOFTDEP("pre: xxhash64"); 2571 MODULE_SOFTDEP("pre: sha256"); 2572 MODULE_SOFTDEP("pre: blake2b-256"); 2573