1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _BCACHEFS_H 3 #define _BCACHEFS_H 4 5 /* 6 * SOME HIGH LEVEL CODE DOCUMENTATION: 7 * 8 * Bcache mostly works with cache sets, cache devices, and backing devices. 9 * 10 * Support for multiple cache devices hasn't quite been finished off yet, but 11 * it's about 95% plumbed through. A cache set and its cache devices is sort of 12 * like a md raid array and its component devices. Most of the code doesn't care 13 * about individual cache devices, the main abstraction is the cache set. 14 * 15 * Multiple cache devices is intended to give us the ability to mirror dirty 16 * cached data and metadata, without mirroring clean cached data. 17 * 18 * Backing devices are different, in that they have a lifetime independent of a 19 * cache set. When you register a newly formatted backing device it'll come up 20 * in passthrough mode, and then you can attach and detach a backing device from 21 * a cache set at runtime - while it's mounted and in use. Detaching implicitly 22 * invalidates any cached data for that backing device. 23 * 24 * A cache set can have multiple (many) backing devices attached to it. 25 * 26 * There's also flash only volumes - this is the reason for the distinction 27 * between struct cached_dev and struct bcache_device. A flash only volume 28 * works much like a bcache device that has a backing device, except the 29 * "cached" data is always dirty. The end result is that we get thin 30 * provisioning with very little additional code. 31 * 32 * Flash only volumes work but they're not production ready because the moving 33 * garbage collector needs more work. More on that later. 34 * 35 * BUCKETS/ALLOCATION: 36 * 37 * Bcache is primarily designed for caching, which means that in normal 38 * operation all of our available space will be allocated. Thus, we need an 39 * efficient way of deleting things from the cache so we can write new things to 40 * it. 41 * 42 * To do this, we first divide the cache device up into buckets. A bucket is the 43 * unit of allocation; they're typically around 1 mb - anywhere from 128k to 2M+ 44 * works efficiently. 45 * 46 * Each bucket has a 16 bit priority, and an 8 bit generation associated with 47 * it. The gens and priorities for all the buckets are stored contiguously and 48 * packed on disk (in a linked list of buckets - aside from the superblock, all 49 * of bcache's metadata is stored in buckets). 50 * 51 * The priority is used to implement an LRU. We reset a bucket's priority when 52 * we allocate it or on cache it, and every so often we decrement the priority 53 * of each bucket. It could be used to implement something more sophisticated, 54 * if anyone ever gets around to it. 55 * 56 * The generation is used for invalidating buckets. Each pointer also has an 8 57 * bit generation embedded in it; for a pointer to be considered valid, its gen 58 * must match the gen of the bucket it points into. Thus, to reuse a bucket all 59 * we have to do is increment its gen (and write its new gen to disk; we batch 60 * this up). 61 * 62 * Bcache is entirely COW - we never write twice to a bucket, even buckets that 63 * contain metadata (including btree nodes). 64 * 65 * THE BTREE: 66 * 67 * Bcache is in large part design around the btree. 68 * 69 * At a high level, the btree is just an index of key -> ptr tuples. 70 * 71 * Keys represent extents, and thus have a size field. Keys also have a variable 72 * number of pointers attached to them (potentially zero, which is handy for 73 * invalidating the cache). 74 * 75 * The key itself is an inode:offset pair. The inode number corresponds to a 76 * backing device or a flash only volume. The offset is the ending offset of the 77 * extent within the inode - not the starting offset; this makes lookups 78 * slightly more convenient. 79 * 80 * Pointers contain the cache device id, the offset on that device, and an 8 bit 81 * generation number. More on the gen later. 82 * 83 * Index lookups are not fully abstracted - cache lookups in particular are 84 * still somewhat mixed in with the btree code, but things are headed in that 85 * direction. 86 * 87 * Updates are fairly well abstracted, though. There are two different ways of 88 * updating the btree; insert and replace. 89 * 90 * BTREE_INSERT will just take a list of keys and insert them into the btree - 91 * overwriting (possibly only partially) any extents they overlap with. This is 92 * used to update the index after a write. 93 * 94 * BTREE_REPLACE is really cmpxchg(); it inserts a key into the btree iff it is 95 * overwriting a key that matches another given key. This is used for inserting 96 * data into the cache after a cache miss, and for background writeback, and for 97 * the moving garbage collector. 98 * 99 * There is no "delete" operation; deleting things from the index is 100 * accomplished by either by invalidating pointers (by incrementing a bucket's 101 * gen) or by inserting a key with 0 pointers - which will overwrite anything 102 * previously present at that location in the index. 103 * 104 * This means that there are always stale/invalid keys in the btree. They're 105 * filtered out by the code that iterates through a btree node, and removed when 106 * a btree node is rewritten. 107 * 108 * BTREE NODES: 109 * 110 * Our unit of allocation is a bucket, and we can't arbitrarily allocate and 111 * free smaller than a bucket - so, that's how big our btree nodes are. 112 * 113 * (If buckets are really big we'll only use part of the bucket for a btree node 114 * - no less than 1/4th - but a bucket still contains no more than a single 115 * btree node. I'd actually like to change this, but for now we rely on the 116 * bucket's gen for deleting btree nodes when we rewrite/split a node.) 117 * 118 * Anyways, btree nodes are big - big enough to be inefficient with a textbook 119 * btree implementation. 120 * 121 * The way this is solved is that btree nodes are internally log structured; we 122 * can append new keys to an existing btree node without rewriting it. This 123 * means each set of keys we write is sorted, but the node is not. 124 * 125 * We maintain this log structure in memory - keeping 1Mb of keys sorted would 126 * be expensive, and we have to distinguish between the keys we have written and 127 * the keys we haven't. So to do a lookup in a btree node, we have to search 128 * each sorted set. But we do merge written sets together lazily, so the cost of 129 * these extra searches is quite low (normally most of the keys in a btree node 130 * will be in one big set, and then there'll be one or two sets that are much 131 * smaller). 132 * 133 * This log structure makes bcache's btree more of a hybrid between a 134 * conventional btree and a compacting data structure, with some of the 135 * advantages of both. 136 * 137 * GARBAGE COLLECTION: 138 * 139 * We can't just invalidate any bucket - it might contain dirty data or 140 * metadata. If it once contained dirty data, other writes might overwrite it 141 * later, leaving no valid pointers into that bucket in the index. 142 * 143 * Thus, the primary purpose of garbage collection is to find buckets to reuse. 144 * It also counts how much valid data it each bucket currently contains, so that 145 * allocation can reuse buckets sooner when they've been mostly overwritten. 146 * 147 * It also does some things that are really internal to the btree 148 * implementation. If a btree node contains pointers that are stale by more than 149 * some threshold, it rewrites the btree node to avoid the bucket's generation 150 * wrapping around. It also merges adjacent btree nodes if they're empty enough. 151 * 152 * THE JOURNAL: 153 * 154 * Bcache's journal is not necessary for consistency; we always strictly 155 * order metadata writes so that the btree and everything else is consistent on 156 * disk in the event of an unclean shutdown, and in fact bcache had writeback 157 * caching (with recovery from unclean shutdown) before journalling was 158 * implemented. 159 * 160 * Rather, the journal is purely a performance optimization; we can't complete a 161 * write until we've updated the index on disk, otherwise the cache would be 162 * inconsistent in the event of an unclean shutdown. This means that without the 163 * journal, on random write workloads we constantly have to update all the leaf 164 * nodes in the btree, and those writes will be mostly empty (appending at most 165 * a few keys each) - highly inefficient in terms of amount of metadata writes, 166 * and it puts more strain on the various btree resorting/compacting code. 167 * 168 * The journal is just a log of keys we've inserted; on startup we just reinsert 169 * all the keys in the open journal entries. That means that when we're updating 170 * a node in the btree, we can wait until a 4k block of keys fills up before 171 * writing them out. 172 * 173 * For simplicity, we only journal updates to leaf nodes; updates to parent 174 * nodes are rare enough (since our leaf nodes are huge) that it wasn't worth 175 * the complexity to deal with journalling them (in particular, journal replay) 176 * - updates to non leaf nodes just happen synchronously (see btree_split()). 177 */ 178 179 #undef pr_fmt 180 #ifdef __KERNEL__ 181 #define pr_fmt(fmt) "bcachefs: %s() " fmt "\n", __func__ 182 #else 183 #define pr_fmt(fmt) "%s() " fmt "\n", __func__ 184 #endif 185 186 #include <linux/backing-dev-defs.h> 187 #include <linux/bug.h> 188 #include <linux/bio.h> 189 #include <linux/closure.h> 190 #include <linux/kobject.h> 191 #include <linux/list.h> 192 #include <linux/math64.h> 193 #include <linux/mutex.h> 194 #include <linux/percpu-refcount.h> 195 #include <linux/percpu-rwsem.h> 196 #include <linux/refcount.h> 197 #include <linux/rhashtable.h> 198 #include <linux/rwsem.h> 199 #include <linux/semaphore.h> 200 #include <linux/seqlock.h> 201 #include <linux/shrinker.h> 202 #include <linux/srcu.h> 203 #include <linux/types.h> 204 #include <linux/workqueue.h> 205 #include <linux/zstd.h> 206 207 #include "bcachefs_format.h" 208 #include "errcode.h" 209 #include "fifo.h" 210 #include "nocow_locking_types.h" 211 #include "opts.h" 212 #include "recovery_types.h" 213 #include "sb-errors_types.h" 214 #include "seqmutex.h" 215 #include "util.h" 216 217 #ifdef CONFIG_BCACHEFS_DEBUG 218 #define BCH_WRITE_REF_DEBUG 219 #endif 220 221 #ifndef dynamic_fault 222 #define dynamic_fault(...) 0 223 #endif 224 225 #define race_fault(...) dynamic_fault("bcachefs:race") 226 227 #define count_event(_c, _name) this_cpu_inc((_c)->counters[BCH_COUNTER_##_name]) 228 229 #define trace_and_count(_c, _name, ...) \ 230 do { \ 231 count_event(_c, _name); \ 232 trace_##_name(__VA_ARGS__); \ 233 } while (0) 234 235 #define bch2_fs_init_fault(name) \ 236 dynamic_fault("bcachefs:bch_fs_init:" name) 237 #define bch2_meta_read_fault(name) \ 238 dynamic_fault("bcachefs:meta:read:" name) 239 #define bch2_meta_write_fault(name) \ 240 dynamic_fault("bcachefs:meta:write:" name) 241 242 #ifdef __KERNEL__ 243 #define BCACHEFS_LOG_PREFIX 244 #endif 245 246 #ifdef BCACHEFS_LOG_PREFIX 247 248 #define bch2_log_msg(_c, fmt) "bcachefs (%s): " fmt, ((_c)->name) 249 #define bch2_fmt_dev(_ca, fmt) "bcachefs (%s): " fmt "\n", ((_ca)->name) 250 #define bch2_fmt_dev_offset(_ca, _offset, fmt) "bcachefs (%s sector %llu): " fmt "\n", ((_ca)->name), (_offset) 251 #define bch2_fmt_inum(_c, _inum, fmt) "bcachefs (%s inum %llu): " fmt "\n", ((_c)->name), (_inum) 252 #define bch2_fmt_inum_offset(_c, _inum, _offset, fmt) \ 253 "bcachefs (%s inum %llu offset %llu): " fmt "\n", ((_c)->name), (_inum), (_offset) 254 255 #else 256 257 #define bch2_log_msg(_c, fmt) fmt 258 #define bch2_fmt_dev(_ca, fmt) "%s: " fmt "\n", ((_ca)->name) 259 #define bch2_fmt_dev_offset(_ca, _offset, fmt) "%s sector %llu: " fmt "\n", ((_ca)->name), (_offset) 260 #define bch2_fmt_inum(_c, _inum, fmt) "inum %llu: " fmt "\n", (_inum) 261 #define bch2_fmt_inum_offset(_c, _inum, _offset, fmt) \ 262 "inum %llu offset %llu: " fmt "\n", (_inum), (_offset) 263 264 #endif 265 266 #define bch2_fmt(_c, fmt) bch2_log_msg(_c, fmt "\n") 267 268 __printf(2, 3) 269 void __bch2_print(struct bch_fs *c, const char *fmt, ...); 270 271 #define maybe_dev_to_fs(_c) _Generic((_c), \ 272 struct bch_dev *: ((struct bch_dev *) (_c))->fs, \ 273 struct bch_fs *: (_c)) 274 275 #define bch2_print(_c, ...) __bch2_print(maybe_dev_to_fs(_c), __VA_ARGS__) 276 277 #define bch2_print_ratelimited(_c, ...) \ 278 do { \ 279 static DEFINE_RATELIMIT_STATE(_rs, \ 280 DEFAULT_RATELIMIT_INTERVAL, \ 281 DEFAULT_RATELIMIT_BURST); \ 282 \ 283 if (__ratelimit(&_rs)) \ 284 bch2_print(_c, __VA_ARGS__); \ 285 } while (0) 286 287 #define bch_info(c, fmt, ...) \ 288 bch2_print(c, KERN_INFO bch2_fmt(c, fmt), ##__VA_ARGS__) 289 #define bch_notice(c, fmt, ...) \ 290 bch2_print(c, KERN_NOTICE bch2_fmt(c, fmt), ##__VA_ARGS__) 291 #define bch_warn(c, fmt, ...) \ 292 bch2_print(c, KERN_WARNING bch2_fmt(c, fmt), ##__VA_ARGS__) 293 #define bch_warn_ratelimited(c, fmt, ...) \ 294 bch2_print_ratelimited(c, KERN_WARNING bch2_fmt(c, fmt), ##__VA_ARGS__) 295 296 #define bch_err(c, fmt, ...) \ 297 bch2_print(c, KERN_ERR bch2_fmt(c, fmt), ##__VA_ARGS__) 298 #define bch_err_dev(ca, fmt, ...) \ 299 bch2_print(c, KERN_ERR bch2_fmt_dev(ca, fmt), ##__VA_ARGS__) 300 #define bch_err_dev_offset(ca, _offset, fmt, ...) \ 301 bch2_print(c, KERN_ERR bch2_fmt_dev_offset(ca, _offset, fmt), ##__VA_ARGS__) 302 #define bch_err_inum(c, _inum, fmt, ...) \ 303 bch2_print(c, KERN_ERR bch2_fmt_inum(c, _inum, fmt), ##__VA_ARGS__) 304 #define bch_err_inum_offset(c, _inum, _offset, fmt, ...) \ 305 bch2_print(c, KERN_ERR bch2_fmt_inum_offset(c, _inum, _offset, fmt), ##__VA_ARGS__) 306 307 #define bch_err_ratelimited(c, fmt, ...) \ 308 bch2_print_ratelimited(c, KERN_ERR bch2_fmt(c, fmt), ##__VA_ARGS__) 309 #define bch_err_dev_ratelimited(ca, fmt, ...) \ 310 bch2_print_ratelimited(ca, KERN_ERR bch2_fmt_dev(ca, fmt), ##__VA_ARGS__) 311 #define bch_err_dev_offset_ratelimited(ca, _offset, fmt, ...) \ 312 bch2_print_ratelimited(ca, KERN_ERR bch2_fmt_dev_offset(ca, _offset, fmt), ##__VA_ARGS__) 313 #define bch_err_inum_ratelimited(c, _inum, fmt, ...) \ 314 bch2_print_ratelimited(c, KERN_ERR bch2_fmt_inum(c, _inum, fmt), ##__VA_ARGS__) 315 #define bch_err_inum_offset_ratelimited(c, _inum, _offset, fmt, ...) \ 316 bch2_print_ratelimited(c, KERN_ERR bch2_fmt_inum_offset(c, _inum, _offset, fmt), ##__VA_ARGS__) 317 318 static inline bool should_print_err(int err) 319 { 320 return err && !bch2_err_matches(err, BCH_ERR_transaction_restart); 321 } 322 323 #define bch_err_fn(_c, _ret) \ 324 do { \ 325 if (should_print_err(_ret)) \ 326 bch_err(_c, "%s(): error %s", __func__, bch2_err_str(_ret));\ 327 } while (0) 328 329 #define bch_err_fn_ratelimited(_c, _ret) \ 330 do { \ 331 if (should_print_err(_ret)) \ 332 bch_err_ratelimited(_c, "%s(): error %s", __func__, bch2_err_str(_ret));\ 333 } while (0) 334 335 #define bch_err_msg(_c, _ret, _msg, ...) \ 336 do { \ 337 if (should_print_err(_ret)) \ 338 bch_err(_c, "%s(): error " _msg " %s", __func__, \ 339 ##__VA_ARGS__, bch2_err_str(_ret)); \ 340 } while (0) 341 342 #define bch_verbose(c, fmt, ...) \ 343 do { \ 344 if ((c)->opts.verbose) \ 345 bch_info(c, fmt, ##__VA_ARGS__); \ 346 } while (0) 347 348 #define pr_verbose_init(opts, fmt, ...) \ 349 do { \ 350 if (opt_get(opts, verbose)) \ 351 pr_info(fmt, ##__VA_ARGS__); \ 352 } while (0) 353 354 /* Parameters that are useful for debugging, but should always be compiled in: */ 355 #define BCH_DEBUG_PARAMS_ALWAYS() \ 356 BCH_DEBUG_PARAM(key_merging_disabled, \ 357 "Disables merging of extents") \ 358 BCH_DEBUG_PARAM(btree_gc_always_rewrite, \ 359 "Causes mark and sweep to compact and rewrite every " \ 360 "btree node it traverses") \ 361 BCH_DEBUG_PARAM(btree_gc_rewrite_disabled, \ 362 "Disables rewriting of btree nodes during mark and sweep")\ 363 BCH_DEBUG_PARAM(btree_shrinker_disabled, \ 364 "Disables the shrinker callback for the btree node cache")\ 365 BCH_DEBUG_PARAM(verify_btree_ondisk, \ 366 "Reread btree nodes at various points to verify the " \ 367 "mergesort in the read path against modifications " \ 368 "done in memory") \ 369 BCH_DEBUG_PARAM(verify_all_btree_replicas, \ 370 "When reading btree nodes, read all replicas and " \ 371 "compare them") \ 372 BCH_DEBUG_PARAM(backpointers_no_use_write_buffer, \ 373 "Don't use the write buffer for backpointers, enabling "\ 374 "extra runtime checks") 375 376 /* Parameters that should only be compiled in debug mode: */ 377 #define BCH_DEBUG_PARAMS_DEBUG() \ 378 BCH_DEBUG_PARAM(expensive_debug_checks, \ 379 "Enables various runtime debugging checks that " \ 380 "significantly affect performance") \ 381 BCH_DEBUG_PARAM(debug_check_iterators, \ 382 "Enables extra verification for btree iterators") \ 383 BCH_DEBUG_PARAM(debug_check_btree_accounting, \ 384 "Verify btree accounting for keys within a node") \ 385 BCH_DEBUG_PARAM(journal_seq_verify, \ 386 "Store the journal sequence number in the version " \ 387 "number of every btree key, and verify that btree " \ 388 "update ordering is preserved during recovery") \ 389 BCH_DEBUG_PARAM(inject_invalid_keys, \ 390 "Store the journal sequence number in the version " \ 391 "number of every btree key, and verify that btree " \ 392 "update ordering is preserved during recovery") \ 393 BCH_DEBUG_PARAM(test_alloc_startup, \ 394 "Force allocator startup to use the slowpath where it" \ 395 "can't find enough free buckets without invalidating" \ 396 "cached data") \ 397 BCH_DEBUG_PARAM(force_reconstruct_read, \ 398 "Force reads to use the reconstruct path, when reading" \ 399 "from erasure coded extents") \ 400 BCH_DEBUG_PARAM(test_restart_gc, \ 401 "Test restarting mark and sweep gc when bucket gens change") 402 403 #define BCH_DEBUG_PARAMS_ALL() BCH_DEBUG_PARAMS_ALWAYS() BCH_DEBUG_PARAMS_DEBUG() 404 405 #ifdef CONFIG_BCACHEFS_DEBUG 406 #define BCH_DEBUG_PARAMS() BCH_DEBUG_PARAMS_ALL() 407 #else 408 #define BCH_DEBUG_PARAMS() BCH_DEBUG_PARAMS_ALWAYS() 409 #endif 410 411 #define BCH_DEBUG_PARAM(name, description) extern bool bch2_##name; 412 BCH_DEBUG_PARAMS() 413 #undef BCH_DEBUG_PARAM 414 415 #ifndef CONFIG_BCACHEFS_DEBUG 416 #define BCH_DEBUG_PARAM(name, description) static const __maybe_unused bool bch2_##name; 417 BCH_DEBUG_PARAMS_DEBUG() 418 #undef BCH_DEBUG_PARAM 419 #endif 420 421 #define BCH_TIME_STATS() \ 422 x(btree_node_mem_alloc) \ 423 x(btree_node_split) \ 424 x(btree_node_compact) \ 425 x(btree_node_merge) \ 426 x(btree_node_sort) \ 427 x(btree_node_read) \ 428 x(btree_node_read_done) \ 429 x(btree_interior_update_foreground) \ 430 x(btree_interior_update_total) \ 431 x(btree_gc) \ 432 x(data_write) \ 433 x(data_read) \ 434 x(data_promote) \ 435 x(journal_flush_write) \ 436 x(journal_noflush_write) \ 437 x(journal_flush_seq) \ 438 x(blocked_journal_low_on_space) \ 439 x(blocked_journal_low_on_pin) \ 440 x(blocked_journal_max_in_flight) \ 441 x(blocked_allocate) \ 442 x(blocked_allocate_open_bucket) \ 443 x(blocked_write_buffer_full) \ 444 x(nocow_lock_contended) 445 446 enum bch_time_stats { 447 #define x(name) BCH_TIME_##name, 448 BCH_TIME_STATS() 449 #undef x 450 BCH_TIME_STAT_NR 451 }; 452 453 #include "alloc_types.h" 454 #include "btree_types.h" 455 #include "btree_write_buffer_types.h" 456 #include "buckets_types.h" 457 #include "buckets_waiting_for_journal_types.h" 458 #include "clock_types.h" 459 #include "disk_groups_types.h" 460 #include "ec_types.h" 461 #include "journal_types.h" 462 #include "keylist_types.h" 463 #include "quota_types.h" 464 #include "rebalance_types.h" 465 #include "replicas_types.h" 466 #include "subvolume_types.h" 467 #include "super_types.h" 468 #include "thread_with_file_types.h" 469 470 /* Number of nodes btree coalesce will try to coalesce at once */ 471 #define GC_MERGE_NODES 4U 472 473 /* Maximum number of nodes we might need to allocate atomically: */ 474 #define BTREE_RESERVE_MAX (BTREE_MAX_DEPTH + (BTREE_MAX_DEPTH - 1)) 475 476 /* Size of the freelist we allocate btree nodes from: */ 477 #define BTREE_NODE_RESERVE (BTREE_RESERVE_MAX * 4) 478 479 #define BTREE_NODE_OPEN_BUCKET_RESERVE (BTREE_RESERVE_MAX * BCH_REPLICAS_MAX) 480 481 struct btree; 482 483 enum gc_phase { 484 GC_PHASE_NOT_RUNNING, 485 GC_PHASE_START, 486 GC_PHASE_SB, 487 488 GC_PHASE_BTREE_stripes, 489 GC_PHASE_BTREE_extents, 490 GC_PHASE_BTREE_inodes, 491 GC_PHASE_BTREE_dirents, 492 GC_PHASE_BTREE_xattrs, 493 GC_PHASE_BTREE_alloc, 494 GC_PHASE_BTREE_quotas, 495 GC_PHASE_BTREE_reflink, 496 GC_PHASE_BTREE_subvolumes, 497 GC_PHASE_BTREE_snapshots, 498 GC_PHASE_BTREE_lru, 499 GC_PHASE_BTREE_freespace, 500 GC_PHASE_BTREE_need_discard, 501 GC_PHASE_BTREE_backpointers, 502 GC_PHASE_BTREE_bucket_gens, 503 GC_PHASE_BTREE_snapshot_trees, 504 GC_PHASE_BTREE_deleted_inodes, 505 GC_PHASE_BTREE_logged_ops, 506 GC_PHASE_BTREE_rebalance_work, 507 508 GC_PHASE_PENDING_DELETE, 509 }; 510 511 struct gc_pos { 512 enum gc_phase phase; 513 struct bpos pos; 514 unsigned level; 515 }; 516 517 struct reflink_gc { 518 u64 offset; 519 u32 size; 520 u32 refcount; 521 }; 522 523 typedef GENRADIX(struct reflink_gc) reflink_gc_table; 524 525 struct io_count { 526 u64 sectors[2][BCH_DATA_NR]; 527 }; 528 529 struct bch_dev { 530 struct kobject kobj; 531 struct percpu_ref ref; 532 struct completion ref_completion; 533 struct percpu_ref io_ref; 534 struct completion io_ref_completion; 535 536 struct bch_fs *fs; 537 538 u8 dev_idx; 539 /* 540 * Cached version of this device's member info from superblock 541 * Committed by bch2_write_super() -> bch_fs_mi_update() 542 */ 543 struct bch_member_cpu mi; 544 atomic64_t errors[BCH_MEMBER_ERROR_NR]; 545 546 __uuid_t uuid; 547 char name[BDEVNAME_SIZE]; 548 549 struct bch_sb_handle disk_sb; 550 struct bch_sb *sb_read_scratch; 551 int sb_write_error; 552 dev_t dev; 553 atomic_t flush_seq; 554 555 struct bch_devs_mask self; 556 557 /* biosets used in cloned bios for writing multiple replicas */ 558 struct bio_set replica_set; 559 560 /* 561 * Buckets: 562 * Per-bucket arrays are protected by c->mark_lock, bucket_lock and 563 * gc_lock, for device resize - holding any is sufficient for access: 564 * Or rcu_read_lock(), but only for ptr_stale(): 565 */ 566 struct bucket_array __rcu *buckets_gc; 567 struct bucket_gens __rcu *bucket_gens; 568 u8 *oldest_gen; 569 unsigned long *buckets_nouse; 570 struct rw_semaphore bucket_lock; 571 572 struct bch_dev_usage *usage_base; 573 struct bch_dev_usage __percpu *usage[JOURNAL_BUF_NR]; 574 struct bch_dev_usage __percpu *usage_gc; 575 576 /* Allocator: */ 577 u64 new_fs_bucket_idx; 578 u64 alloc_cursor; 579 580 unsigned nr_open_buckets; 581 unsigned nr_btree_reserve; 582 583 size_t inc_gen_needs_gc; 584 size_t inc_gen_really_needs_gc; 585 size_t buckets_waiting_on_journal; 586 587 atomic64_t rebalance_work; 588 589 struct journal_device journal; 590 u64 prev_journal_sector; 591 592 struct work_struct io_error_work; 593 594 /* The rest of this all shows up in sysfs */ 595 atomic64_t cur_latency[2]; 596 struct bch2_time_stats io_latency[2]; 597 598 #define CONGESTED_MAX 1024 599 atomic_t congested; 600 u64 congested_last; 601 602 struct io_count __percpu *io_done; 603 }; 604 605 /* 606 * initial_gc_unfixed 607 * error 608 * topology error 609 */ 610 611 #define BCH_FS_FLAGS() \ 612 x(started) \ 613 x(may_go_rw) \ 614 x(rw) \ 615 x(was_rw) \ 616 x(stopping) \ 617 x(emergency_ro) \ 618 x(going_ro) \ 619 x(write_disable_complete) \ 620 x(clean_shutdown) \ 621 x(fsck_running) \ 622 x(initial_gc_unfixed) \ 623 x(need_another_gc) \ 624 x(need_delete_dead_snapshots) \ 625 x(error) \ 626 x(topology_error) \ 627 x(errors_fixed) \ 628 x(errors_not_fixed) 629 630 enum bch_fs_flags { 631 #define x(n) BCH_FS_##n, 632 BCH_FS_FLAGS() 633 #undef x 634 }; 635 636 struct btree_debug { 637 unsigned id; 638 }; 639 640 #define BCH_TRANSACTIONS_NR 128 641 642 struct btree_transaction_stats { 643 struct bch2_time_stats duration; 644 struct bch2_time_stats lock_hold_times; 645 struct mutex lock; 646 unsigned nr_max_paths; 647 unsigned journal_entries_size; 648 unsigned max_mem; 649 char *max_paths_text; 650 }; 651 652 struct bch_fs_pcpu { 653 u64 sectors_available; 654 }; 655 656 struct journal_seq_blacklist_table { 657 size_t nr; 658 struct journal_seq_blacklist_table_entry { 659 u64 start; 660 u64 end; 661 bool dirty; 662 } entries[]; 663 }; 664 665 struct journal_keys { 666 struct journal_key { 667 u64 journal_seq; 668 u32 journal_offset; 669 enum btree_id btree_id:8; 670 unsigned level:8; 671 bool allocated; 672 bool overwritten; 673 struct bkey_i *k; 674 } *d; 675 /* 676 * Gap buffer: instead of all the empty space in the array being at the 677 * end of the buffer - from @nr to @size - the empty space is at @gap. 678 * This means that sequential insertions are O(n) instead of O(n^2). 679 */ 680 size_t gap; 681 size_t nr; 682 size_t size; 683 atomic_t ref; 684 bool initial_ref_held; 685 }; 686 687 struct btree_trans_buf { 688 struct btree_trans *trans; 689 }; 690 691 #define REPLICAS_DELTA_LIST_MAX (1U << 16) 692 693 #define BCACHEFS_ROOT_SUBVOL_INUM \ 694 ((subvol_inum) { BCACHEFS_ROOT_SUBVOL, BCACHEFS_ROOT_INO }) 695 696 #define BCH_WRITE_REFS() \ 697 x(trans) \ 698 x(write) \ 699 x(promote) \ 700 x(node_rewrite) \ 701 x(stripe_create) \ 702 x(stripe_delete) \ 703 x(reflink) \ 704 x(fallocate) \ 705 x(discard) \ 706 x(invalidate) \ 707 x(delete_dead_snapshots) \ 708 x(snapshot_delete_pagecache) \ 709 x(sysfs) \ 710 x(btree_write_buffer) 711 712 enum bch_write_ref { 713 #define x(n) BCH_WRITE_REF_##n, 714 BCH_WRITE_REFS() 715 #undef x 716 BCH_WRITE_REF_NR, 717 }; 718 719 struct bch_fs { 720 struct closure cl; 721 722 struct list_head list; 723 struct kobject kobj; 724 struct kobject counters_kobj; 725 struct kobject internal; 726 struct kobject opts_dir; 727 struct kobject time_stats; 728 unsigned long flags; 729 730 int minor; 731 struct device *chardev; 732 struct super_block *vfs_sb; 733 dev_t dev; 734 char name[40]; 735 struct stdio_redirect *stdio; 736 struct task_struct *stdio_filter; 737 738 /* ro/rw, add/remove/resize devices: */ 739 struct rw_semaphore state_lock; 740 741 /* Counts outstanding writes, for clean transition to read-only */ 742 #ifdef BCH_WRITE_REF_DEBUG 743 atomic_long_t writes[BCH_WRITE_REF_NR]; 744 #else 745 struct percpu_ref writes; 746 #endif 747 /* 748 * Analagous to c->writes, for asynchronous ops that don't necessarily 749 * need fs to be read-write 750 */ 751 refcount_t ro_ref; 752 wait_queue_head_t ro_ref_wait; 753 754 struct work_struct read_only_work; 755 756 struct bch_dev __rcu *devs[BCH_SB_MEMBERS_MAX]; 757 758 struct bch_replicas_cpu replicas; 759 struct bch_replicas_cpu replicas_gc; 760 struct mutex replicas_gc_lock; 761 mempool_t replicas_delta_pool; 762 763 struct journal_entry_res btree_root_journal_res; 764 struct journal_entry_res replicas_journal_res; 765 struct journal_entry_res clock_journal_res; 766 struct journal_entry_res dev_usage_journal_res; 767 768 struct bch_disk_groups_cpu __rcu *disk_groups; 769 770 struct bch_opts opts; 771 772 /* Updated by bch2_sb_update():*/ 773 struct { 774 __uuid_t uuid; 775 __uuid_t user_uuid; 776 777 u16 version; 778 u16 version_min; 779 u16 version_upgrade_complete; 780 781 u8 nr_devices; 782 u8 clean; 783 784 u8 encryption_type; 785 786 u64 time_base_lo; 787 u32 time_base_hi; 788 unsigned time_units_per_sec; 789 unsigned nsec_per_time_unit; 790 u64 features; 791 u64 compat; 792 unsigned long errors_silent[BITS_TO_LONGS(BCH_SB_ERR_MAX)]; 793 } sb; 794 795 796 struct bch_sb_handle disk_sb; 797 798 unsigned short block_bits; /* ilog2(block_size) */ 799 800 u16 btree_foreground_merge_threshold; 801 802 struct closure sb_write; 803 struct mutex sb_lock; 804 805 /* snapshot.c: */ 806 struct snapshot_table __rcu *snapshots; 807 size_t snapshot_table_size; 808 struct mutex snapshot_table_lock; 809 struct rw_semaphore snapshot_create_lock; 810 811 struct work_struct snapshot_delete_work; 812 struct work_struct snapshot_wait_for_pagecache_and_delete_work; 813 snapshot_id_list snapshots_unlinked; 814 struct mutex snapshots_unlinked_lock; 815 816 /* BTREE CACHE */ 817 struct bio_set btree_bio; 818 struct workqueue_struct *io_complete_wq; 819 820 struct btree_root btree_roots_known[BTREE_ID_NR]; 821 DARRAY(struct btree_root) btree_roots_extra; 822 struct mutex btree_root_lock; 823 824 struct btree_cache btree_cache; 825 826 /* 827 * Cache of allocated btree nodes - if we allocate a btree node and 828 * don't use it, if we free it that space can't be reused until going 829 * _all_ the way through the allocator (which exposes us to a livelock 830 * when allocating btree reserves fail halfway through) - instead, we 831 * can stick them here: 832 */ 833 struct btree_alloc btree_reserve_cache[BTREE_NODE_RESERVE * 2]; 834 unsigned btree_reserve_cache_nr; 835 struct mutex btree_reserve_cache_lock; 836 837 mempool_t btree_interior_update_pool; 838 struct list_head btree_interior_update_list; 839 struct list_head btree_interior_updates_unwritten; 840 struct mutex btree_interior_update_lock; 841 struct closure_waitlist btree_interior_update_wait; 842 843 struct workqueue_struct *btree_interior_update_worker; 844 struct work_struct btree_interior_update_work; 845 846 struct list_head pending_node_rewrites; 847 struct mutex pending_node_rewrites_lock; 848 849 /* btree_io.c: */ 850 spinlock_t btree_write_error_lock; 851 struct btree_write_stats { 852 atomic64_t nr; 853 atomic64_t bytes; 854 } btree_write_stats[BTREE_WRITE_TYPE_NR]; 855 856 /* btree_iter.c: */ 857 struct seqmutex btree_trans_lock; 858 struct list_head btree_trans_list; 859 mempool_t btree_trans_pool; 860 mempool_t btree_trans_mem_pool; 861 struct btree_trans_buf __percpu *btree_trans_bufs; 862 863 struct srcu_struct btree_trans_barrier; 864 bool btree_trans_barrier_initialized; 865 866 struct btree_key_cache btree_key_cache; 867 unsigned btree_key_cache_btrees; 868 869 struct btree_write_buffer btree_write_buffer; 870 871 struct workqueue_struct *btree_update_wq; 872 struct workqueue_struct *btree_io_complete_wq; 873 /* copygc needs its own workqueue for index updates.. */ 874 struct workqueue_struct *copygc_wq; 875 /* 876 * Use a dedicated wq for write ref holder tasks. Required to avoid 877 * dependency problems with other wq tasks that can block on ref 878 * draining, such as read-only transition. 879 */ 880 struct workqueue_struct *write_ref_wq; 881 882 /* ALLOCATION */ 883 struct bch_devs_mask rw_devs[BCH_DATA_NR]; 884 885 u64 capacity; /* sectors */ 886 887 /* 888 * When capacity _decreases_ (due to a disk being removed), we 889 * increment capacity_gen - this invalidates outstanding reservations 890 * and forces them to be revalidated 891 */ 892 u32 capacity_gen; 893 unsigned bucket_size_max; 894 895 atomic64_t sectors_available; 896 struct mutex sectors_available_lock; 897 898 struct bch_fs_pcpu __percpu *pcpu; 899 900 struct percpu_rw_semaphore mark_lock; 901 902 seqcount_t usage_lock; 903 struct bch_fs_usage *usage_base; 904 struct bch_fs_usage __percpu *usage[JOURNAL_BUF_NR]; 905 struct bch_fs_usage __percpu *usage_gc; 906 u64 __percpu *online_reserved; 907 908 /* single element mempool: */ 909 struct mutex usage_scratch_lock; 910 struct bch_fs_usage_online *usage_scratch; 911 912 struct io_clock io_clock[2]; 913 914 /* JOURNAL SEQ BLACKLIST */ 915 struct journal_seq_blacklist_table * 916 journal_seq_blacklist_table; 917 struct work_struct journal_seq_blacklist_gc_work; 918 919 /* ALLOCATOR */ 920 spinlock_t freelist_lock; 921 struct closure_waitlist freelist_wait; 922 u64 blocked_allocate; 923 u64 blocked_allocate_open_bucket; 924 925 open_bucket_idx_t open_buckets_freelist; 926 open_bucket_idx_t open_buckets_nr_free; 927 struct closure_waitlist open_buckets_wait; 928 struct open_bucket open_buckets[OPEN_BUCKETS_COUNT]; 929 open_bucket_idx_t open_buckets_hash[OPEN_BUCKETS_COUNT]; 930 931 open_bucket_idx_t open_buckets_partial[OPEN_BUCKETS_COUNT]; 932 open_bucket_idx_t open_buckets_partial_nr; 933 934 struct write_point btree_write_point; 935 struct write_point rebalance_write_point; 936 937 struct write_point write_points[WRITE_POINT_MAX]; 938 struct hlist_head write_points_hash[WRITE_POINT_HASH_NR]; 939 struct mutex write_points_hash_lock; 940 unsigned write_points_nr; 941 942 struct buckets_waiting_for_journal buckets_waiting_for_journal; 943 struct work_struct discard_work; 944 struct work_struct invalidate_work; 945 946 /* GARBAGE COLLECTION */ 947 struct task_struct *gc_thread; 948 atomic_t kick_gc; 949 unsigned long gc_count; 950 951 enum btree_id gc_gens_btree; 952 struct bpos gc_gens_pos; 953 954 /* 955 * Tracks GC's progress - everything in the range [ZERO_KEY..gc_cur_pos] 956 * has been marked by GC. 957 * 958 * gc_cur_phase is a superset of btree_ids (BTREE_ID_extents etc.) 959 * 960 * Protected by gc_pos_lock. Only written to by GC thread, so GC thread 961 * can read without a lock. 962 */ 963 seqcount_t gc_pos_lock; 964 struct gc_pos gc_pos; 965 966 /* 967 * The allocation code needs gc_mark in struct bucket to be correct, but 968 * it's not while a gc is in progress. 969 */ 970 struct rw_semaphore gc_lock; 971 struct mutex gc_gens_lock; 972 973 /* IO PATH */ 974 struct semaphore io_in_flight; 975 struct bio_set bio_read; 976 struct bio_set bio_read_split; 977 struct bio_set bio_write; 978 struct mutex bio_bounce_pages_lock; 979 mempool_t bio_bounce_pages; 980 struct bucket_nocow_lock_table 981 nocow_locks; 982 struct rhashtable promote_table; 983 984 mempool_t compression_bounce[2]; 985 mempool_t compress_workspace[BCH_COMPRESSION_TYPE_NR]; 986 mempool_t decompress_workspace; 987 size_t zstd_workspace_size; 988 989 struct crypto_shash *sha256; 990 struct crypto_sync_skcipher *chacha20; 991 struct crypto_shash *poly1305; 992 993 atomic64_t key_version; 994 995 mempool_t large_bkey_pool; 996 997 /* MOVE.C */ 998 struct list_head moving_context_list; 999 struct mutex moving_context_lock; 1000 1001 /* REBALANCE */ 1002 struct bch_fs_rebalance rebalance; 1003 1004 /* COPYGC */ 1005 struct task_struct *copygc_thread; 1006 struct write_point copygc_write_point; 1007 s64 copygc_wait_at; 1008 s64 copygc_wait; 1009 bool copygc_running; 1010 wait_queue_head_t copygc_running_wq; 1011 1012 /* STRIPES: */ 1013 GENRADIX(struct stripe) stripes; 1014 GENRADIX(struct gc_stripe) gc_stripes; 1015 1016 struct hlist_head ec_stripes_new[32]; 1017 spinlock_t ec_stripes_new_lock; 1018 1019 ec_stripes_heap ec_stripes_heap; 1020 struct mutex ec_stripes_heap_lock; 1021 1022 /* ERASURE CODING */ 1023 struct list_head ec_stripe_head_list; 1024 struct mutex ec_stripe_head_lock; 1025 1026 struct list_head ec_stripe_new_list; 1027 struct mutex ec_stripe_new_lock; 1028 wait_queue_head_t ec_stripe_new_wait; 1029 1030 struct work_struct ec_stripe_create_work; 1031 u64 ec_stripe_hint; 1032 1033 struct work_struct ec_stripe_delete_work; 1034 1035 struct bio_set ec_bioset; 1036 1037 /* REFLINK */ 1038 reflink_gc_table reflink_gc_table; 1039 size_t reflink_gc_nr; 1040 1041 /* fs.c */ 1042 struct list_head vfs_inodes_list; 1043 struct mutex vfs_inodes_lock; 1044 1045 /* VFS IO PATH - fs-io.c */ 1046 struct bio_set writepage_bioset; 1047 struct bio_set dio_write_bioset; 1048 struct bio_set dio_read_bioset; 1049 struct bio_set nocow_flush_bioset; 1050 1051 /* QUOTAS */ 1052 struct bch_memquota_type quotas[QTYP_NR]; 1053 1054 /* RECOVERY */ 1055 u64 journal_replay_seq_start; 1056 u64 journal_replay_seq_end; 1057 /* 1058 * Two different uses: 1059 * "Has this fsck pass?" - i.e. should this type of error be an 1060 * emergency read-only 1061 * And, in certain situations fsck will rewind to an earlier pass: used 1062 * for signaling to the toplevel code which pass we want to run now. 1063 */ 1064 enum bch_recovery_pass curr_recovery_pass; 1065 /* bitmap of explicitly enabled recovery passes: */ 1066 u64 recovery_passes_explicit; 1067 /* bitmask of recovery passes that we actually ran */ 1068 u64 recovery_passes_complete; 1069 /* never rewinds version of curr_recovery_pass */ 1070 enum bch_recovery_pass recovery_pass_done; 1071 struct semaphore online_fsck_mutex; 1072 1073 /* DEBUG JUNK */ 1074 struct dentry *fs_debug_dir; 1075 struct dentry *btree_debug_dir; 1076 struct btree_debug btree_debug[BTREE_ID_NR]; 1077 struct btree *verify_data; 1078 struct btree_node *verify_ondisk; 1079 struct mutex verify_lock; 1080 1081 u64 *unused_inode_hints; 1082 unsigned inode_shard_bits; 1083 1084 /* 1085 * A btree node on disk could have too many bsets for an iterator to fit 1086 * on the stack - have to dynamically allocate them 1087 */ 1088 mempool_t fill_iter; 1089 1090 mempool_t btree_bounce_pool; 1091 1092 struct journal journal; 1093 GENRADIX(struct journal_replay *) journal_entries; 1094 u64 journal_entries_base_seq; 1095 struct journal_keys journal_keys; 1096 struct list_head journal_iters; 1097 1098 u64 last_bucket_seq_cleanup; 1099 1100 u64 counters_on_mount[BCH_COUNTER_NR]; 1101 u64 __percpu *counters; 1102 1103 unsigned btree_gc_periodic:1; 1104 unsigned copy_gc_enabled:1; 1105 bool promote_whole_extents; 1106 1107 struct bch2_time_stats times[BCH_TIME_STAT_NR]; 1108 1109 struct btree_transaction_stats btree_transaction_stats[BCH_TRANSACTIONS_NR]; 1110 1111 /* ERRORS */ 1112 struct list_head fsck_error_msgs; 1113 struct mutex fsck_error_msgs_lock; 1114 bool fsck_alloc_msgs_err; 1115 1116 bch_sb_errors_cpu fsck_error_counts; 1117 struct mutex fsck_error_counts_lock; 1118 }; 1119 1120 extern struct wait_queue_head bch2_read_only_wait; 1121 1122 static inline void bch2_write_ref_get(struct bch_fs *c, enum bch_write_ref ref) 1123 { 1124 #ifdef BCH_WRITE_REF_DEBUG 1125 atomic_long_inc(&c->writes[ref]); 1126 #else 1127 percpu_ref_get(&c->writes); 1128 #endif 1129 } 1130 1131 static inline bool __bch2_write_ref_tryget(struct bch_fs *c, enum bch_write_ref ref) 1132 { 1133 #ifdef BCH_WRITE_REF_DEBUG 1134 return !test_bit(BCH_FS_going_ro, &c->flags) && 1135 atomic_long_inc_not_zero(&c->writes[ref]); 1136 #else 1137 return percpu_ref_tryget(&c->writes); 1138 #endif 1139 } 1140 1141 static inline bool bch2_write_ref_tryget(struct bch_fs *c, enum bch_write_ref ref) 1142 { 1143 #ifdef BCH_WRITE_REF_DEBUG 1144 return !test_bit(BCH_FS_going_ro, &c->flags) && 1145 atomic_long_inc_not_zero(&c->writes[ref]); 1146 #else 1147 return percpu_ref_tryget_live(&c->writes); 1148 #endif 1149 } 1150 1151 static inline void bch2_write_ref_put(struct bch_fs *c, enum bch_write_ref ref) 1152 { 1153 #ifdef BCH_WRITE_REF_DEBUG 1154 long v = atomic_long_dec_return(&c->writes[ref]); 1155 1156 BUG_ON(v < 0); 1157 if (v) 1158 return; 1159 for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++) 1160 if (atomic_long_read(&c->writes[i])) 1161 return; 1162 1163 set_bit(BCH_FS_write_disable_complete, &c->flags); 1164 wake_up(&bch2_read_only_wait); 1165 #else 1166 percpu_ref_put(&c->writes); 1167 #endif 1168 } 1169 1170 static inline bool bch2_ro_ref_tryget(struct bch_fs *c) 1171 { 1172 if (test_bit(BCH_FS_stopping, &c->flags)) 1173 return false; 1174 1175 return refcount_inc_not_zero(&c->ro_ref); 1176 } 1177 1178 static inline void bch2_ro_ref_put(struct bch_fs *c) 1179 { 1180 if (refcount_dec_and_test(&c->ro_ref)) 1181 wake_up(&c->ro_ref_wait); 1182 } 1183 1184 static inline void bch2_set_ra_pages(struct bch_fs *c, unsigned ra_pages) 1185 { 1186 #ifndef NO_BCACHEFS_FS 1187 if (c->vfs_sb) 1188 c->vfs_sb->s_bdi->ra_pages = ra_pages; 1189 #endif 1190 } 1191 1192 static inline unsigned bucket_bytes(const struct bch_dev *ca) 1193 { 1194 return ca->mi.bucket_size << 9; 1195 } 1196 1197 static inline unsigned block_bytes(const struct bch_fs *c) 1198 { 1199 return c->opts.block_size; 1200 } 1201 1202 static inline unsigned block_sectors(const struct bch_fs *c) 1203 { 1204 return c->opts.block_size >> 9; 1205 } 1206 1207 static inline bool btree_id_cached(const struct bch_fs *c, enum btree_id btree) 1208 { 1209 return c->btree_key_cache_btrees & (1U << btree); 1210 } 1211 1212 static inline struct timespec64 bch2_time_to_timespec(const struct bch_fs *c, s64 time) 1213 { 1214 struct timespec64 t; 1215 s32 rem; 1216 1217 time += c->sb.time_base_lo; 1218 1219 t.tv_sec = div_s64_rem(time, c->sb.time_units_per_sec, &rem); 1220 t.tv_nsec = rem * c->sb.nsec_per_time_unit; 1221 return t; 1222 } 1223 1224 static inline s64 timespec_to_bch2_time(const struct bch_fs *c, struct timespec64 ts) 1225 { 1226 return (ts.tv_sec * c->sb.time_units_per_sec + 1227 (int) ts.tv_nsec / c->sb.nsec_per_time_unit) - c->sb.time_base_lo; 1228 } 1229 1230 static inline s64 bch2_current_time(const struct bch_fs *c) 1231 { 1232 struct timespec64 now; 1233 1234 ktime_get_coarse_real_ts64(&now); 1235 return timespec_to_bch2_time(c, now); 1236 } 1237 1238 static inline bool bch2_dev_exists2(const struct bch_fs *c, unsigned dev) 1239 { 1240 return dev < c->sb.nr_devices && c->devs[dev]; 1241 } 1242 1243 static inline struct stdio_redirect *bch2_fs_stdio_redirect(struct bch_fs *c) 1244 { 1245 struct stdio_redirect *stdio = c->stdio; 1246 1247 if (c->stdio_filter && c->stdio_filter != current) 1248 stdio = NULL; 1249 return stdio; 1250 } 1251 1252 #define BKEY_PADDED_ONSTACK(key, pad) \ 1253 struct { struct bkey_i key; __u64 key ## _pad[pad]; } 1254 1255 #endif /* _BCACHEFS_H */ 1256