1 #ifndef _RAID5_H 2 #define _RAID5_H 3 4 #include <linux/raid/xor.h> 5 #include <linux/dmaengine.h> 6 7 /* 8 * 9 * Each stripe contains one buffer per device. Each buffer can be in 10 * one of a number of states stored in "flags". Changes between 11 * these states happen *almost* exclusively under the protection of the 12 * STRIPE_ACTIVE flag. Some very specific changes can happen in bi_end_io, and 13 * these are not protected by STRIPE_ACTIVE. 14 * 15 * The flag bits that are used to represent these states are: 16 * R5_UPTODATE and R5_LOCKED 17 * 18 * State Empty == !UPTODATE, !LOCK 19 * We have no data, and there is no active request 20 * State Want == !UPTODATE, LOCK 21 * A read request is being submitted for this block 22 * State Dirty == UPTODATE, LOCK 23 * Some new data is in this buffer, and it is being written out 24 * State Clean == UPTODATE, !LOCK 25 * We have valid data which is the same as on disc 26 * 27 * The possible state transitions are: 28 * 29 * Empty -> Want - on read or write to get old data for parity calc 30 * Empty -> Dirty - on compute_parity to satisfy write/sync request. 31 * Empty -> Clean - on compute_block when computing a block for failed drive 32 * Want -> Empty - on failed read 33 * Want -> Clean - on successful completion of read request 34 * Dirty -> Clean - on successful completion of write request 35 * Dirty -> Clean - on failed write 36 * Clean -> Dirty - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW) 37 * 38 * The Want->Empty, Want->Clean, Dirty->Clean, transitions 39 * all happen in b_end_io at interrupt time. 40 * Each sets the Uptodate bit before releasing the Lock bit. 41 * This leaves one multi-stage transition: 42 * Want->Dirty->Clean 43 * This is safe because thinking that a Clean buffer is actually dirty 44 * will at worst delay some action, and the stripe will be scheduled 45 * for attention after the transition is complete. 46 * 47 * There is one possibility that is not covered by these states. That 48 * is if one drive has failed and there is a spare being rebuilt. We 49 * can't distinguish between a clean block that has been generated 50 * from parity calculations, and a clean block that has been 51 * successfully written to the spare ( or to parity when resyncing). 52 * To distinguish these states we have a stripe bit STRIPE_INSYNC that 53 * is set whenever a write is scheduled to the spare, or to the parity 54 * disc if there is no spare. A sync request clears this bit, and 55 * when we find it set with no buffers locked, we know the sync is 56 * complete. 57 * 58 * Buffers for the md device that arrive via make_request are attached 59 * to the appropriate stripe in one of two lists linked on b_reqnext. 60 * One list (bh_read) for read requests, one (bh_write) for write. 61 * There should never be more than one buffer on the two lists 62 * together, but we are not guaranteed of that so we allow for more. 63 * 64 * If a buffer is on the read list when the associated cache buffer is 65 * Uptodate, the data is copied into the read buffer and it's b_end_io 66 * routine is called. This may happen in the end_request routine only 67 * if the buffer has just successfully been read. end_request should 68 * remove the buffers from the list and then set the Uptodate bit on 69 * the buffer. Other threads may do this only if they first check 70 * that the Uptodate bit is set. Once they have checked that they may 71 * take buffers off the read queue. 72 * 73 * When a buffer on the write list is committed for write it is copied 74 * into the cache buffer, which is then marked dirty, and moved onto a 75 * third list, the written list (bh_written). Once both the parity 76 * block and the cached buffer are successfully written, any buffer on 77 * a written list can be returned with b_end_io. 78 * 79 * The write list and read list both act as fifos. The read list, 80 * write list and written list are protected by the device_lock. 81 * The device_lock is only for list manipulations and will only be 82 * held for a very short time. It can be claimed from interrupts. 83 * 84 * 85 * Stripes in the stripe cache can be on one of two lists (or on 86 * neither). The "inactive_list" contains stripes which are not 87 * currently being used for any request. They can freely be reused 88 * for another stripe. The "handle_list" contains stripes that need 89 * to be handled in some way. Both of these are fifo queues. Each 90 * stripe is also (potentially) linked to a hash bucket in the hash 91 * table so that it can be found by sector number. Stripes that are 92 * not hashed must be on the inactive_list, and will normally be at 93 * the front. All stripes start life this way. 94 * 95 * The inactive_list, handle_list and hash bucket lists are all protected by the 96 * device_lock. 97 * - stripes have a reference counter. If count==0, they are on a list. 98 * - If a stripe might need handling, STRIPE_HANDLE is set. 99 * - When refcount reaches zero, then if STRIPE_HANDLE it is put on 100 * handle_list else inactive_list 101 * 102 * This, combined with the fact that STRIPE_HANDLE is only ever 103 * cleared while a stripe has a non-zero count means that if the 104 * refcount is 0 and STRIPE_HANDLE is set, then it is on the 105 * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then 106 * the stripe is on inactive_list. 107 * 108 * The possible transitions are: 109 * activate an unhashed/inactive stripe (get_active_stripe()) 110 * lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev 111 * activate a hashed, possibly active stripe (get_active_stripe()) 112 * lockdev check-hash if(!cnt++)unlink-stripe unlockdev 113 * attach a request to an active stripe (add_stripe_bh()) 114 * lockdev attach-buffer unlockdev 115 * handle a stripe (handle_stripe()) 116 * setSTRIPE_ACTIVE, clrSTRIPE_HANDLE ... 117 * (lockdev check-buffers unlockdev) .. 118 * change-state .. 119 * record io/ops needed clearSTRIPE_ACTIVE schedule io/ops 120 * release an active stripe (release_stripe()) 121 * lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev 122 * 123 * The refcount counts each thread that have activated the stripe, 124 * plus raid5d if it is handling it, plus one for each active request 125 * on a cached buffer, and plus one if the stripe is undergoing stripe 126 * operations. 127 * 128 * The stripe operations are: 129 * -copying data between the stripe cache and user application buffers 130 * -computing blocks to save a disk access, or to recover a missing block 131 * -updating the parity on a write operation (reconstruct write and 132 * read-modify-write) 133 * -checking parity correctness 134 * -running i/o to disk 135 * These operations are carried out by raid5_run_ops which uses the async_tx 136 * api to (optionally) offload operations to dedicated hardware engines. 137 * When requesting an operation handle_stripe sets the pending bit for the 138 * operation and increments the count. raid5_run_ops is then run whenever 139 * the count is non-zero. 140 * There are some critical dependencies between the operations that prevent some 141 * from being requested while another is in flight. 142 * 1/ Parity check operations destroy the in cache version of the parity block, 143 * so we prevent parity dependent operations like writes and compute_blocks 144 * from starting while a check is in progress. Some dma engines can perform 145 * the check without damaging the parity block, in these cases the parity 146 * block is re-marked up to date (assuming the check was successful) and is 147 * not re-read from disk. 148 * 2/ When a write operation is requested we immediately lock the affected 149 * blocks, and mark them as not up to date. This causes new read requests 150 * to be held off, as well as parity checks and compute block operations. 151 * 3/ Once a compute block operation has been requested handle_stripe treats 152 * that block as if it is up to date. raid5_run_ops guaruntees that any 153 * operation that is dependent on the compute block result is initiated after 154 * the compute block completes. 155 */ 156 157 /* 158 * Operations state - intermediate states that are visible outside of 159 * STRIPE_ACTIVE. 160 * In general _idle indicates nothing is running, _run indicates a data 161 * processing operation is active, and _result means the data processing result 162 * is stable and can be acted upon. For simple operations like biofill and 163 * compute that only have an _idle and _run state they are indicated with 164 * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN) 165 */ 166 /** 167 * enum check_states - handles syncing / repairing a stripe 168 * @check_state_idle - check operations are quiesced 169 * @check_state_run - check operation is running 170 * @check_state_result - set outside lock when check result is valid 171 * @check_state_compute_run - check failed and we are repairing 172 * @check_state_compute_result - set outside lock when compute result is valid 173 */ 174 enum check_states { 175 check_state_idle = 0, 176 check_state_run, /* xor parity check */ 177 check_state_run_q, /* q-parity check */ 178 check_state_run_pq, /* pq dual parity check */ 179 check_state_check_result, 180 check_state_compute_run, /* parity repair */ 181 check_state_compute_result, 182 }; 183 184 /** 185 * enum reconstruct_states - handles writing or expanding a stripe 186 */ 187 enum reconstruct_states { 188 reconstruct_state_idle = 0, 189 reconstruct_state_prexor_drain_run, /* prexor-write */ 190 reconstruct_state_drain_run, /* write */ 191 reconstruct_state_run, /* expand */ 192 reconstruct_state_prexor_drain_result, 193 reconstruct_state_drain_result, 194 reconstruct_state_result, 195 }; 196 197 struct stripe_head { 198 struct hlist_node hash; 199 struct list_head lru; /* inactive_list or handle_list */ 200 struct llist_node release_list; 201 struct r5conf *raid_conf; 202 short generation; /* increments with every 203 * reshape */ 204 sector_t sector; /* sector of this row */ 205 short pd_idx; /* parity disk index */ 206 short qd_idx; /* 'Q' disk index for raid6 */ 207 short ddf_layout;/* use DDF ordering to calculate Q */ 208 short hash_lock_index; 209 unsigned long state; /* state flags */ 210 atomic_t count; /* nr of active thread/requests */ 211 int bm_seq; /* sequence number for bitmap flushes */ 212 int disks; /* disks in stripe */ 213 int overwrite_disks; /* total overwrite disks in stripe, 214 * this is only checked when stripe 215 * has STRIPE_BATCH_READY 216 */ 217 enum check_states check_state; 218 enum reconstruct_states reconstruct_state; 219 spinlock_t stripe_lock; 220 int cpu; 221 struct r5worker_group *group; 222 223 struct stripe_head *batch_head; /* protected by stripe lock */ 224 spinlock_t batch_lock; /* only header's lock is useful */ 225 struct list_head batch_list; /* protected by head's batch lock*/ 226 227 struct r5l_io_unit *log_io; 228 struct list_head log_list; 229 sector_t log_start; /* first meta block on the journal */ 230 struct list_head r5c; /* for r5c_cache->stripe_in_journal */ 231 /** 232 * struct stripe_operations 233 * @target - STRIPE_OP_COMPUTE_BLK target 234 * @target2 - 2nd compute target in the raid6 case 235 * @zero_sum_result - P and Q verification flags 236 * @request - async service request flags for raid_run_ops 237 */ 238 struct stripe_operations { 239 int target, target2; 240 enum sum_check_flags zero_sum_result; 241 } ops; 242 struct r5dev { 243 /* rreq and rvec are used for the replacement device when 244 * writing data to both devices. 245 */ 246 struct bio req, rreq; 247 struct bio_vec vec, rvec; 248 struct page *page, *orig_page; 249 struct bio *toread, *read, *towrite, *written; 250 sector_t sector; /* sector of this page */ 251 unsigned long flags; 252 u32 log_checksum; 253 } dev[1]; /* allocated with extra space depending of RAID geometry */ 254 }; 255 256 /* stripe_head_state - collects and tracks the dynamic state of a stripe_head 257 * for handle_stripe. 258 */ 259 struct stripe_head_state { 260 /* 'syncing' means that we need to read all devices, either 261 * to check/correct parity, or to reconstruct a missing device. 262 * 'replacing' means we are replacing one or more drives and 263 * the source is valid at this point so we don't need to 264 * read all devices, just the replacement targets. 265 */ 266 int syncing, expanding, expanded, replacing; 267 int locked, uptodate, to_read, to_write, failed, written; 268 int to_fill, compute, req_compute, non_overwrite; 269 int injournal, just_cached; 270 int failed_num[2]; 271 int p_failed, q_failed; 272 int dec_preread_active; 273 unsigned long ops_request; 274 275 struct bio_list return_bi; 276 struct md_rdev *blocked_rdev; 277 int handle_bad_blocks; 278 int log_failed; 279 int waiting_extra_page; 280 }; 281 282 /* Flags for struct r5dev.flags */ 283 enum r5dev_flags { 284 R5_UPTODATE, /* page contains current data */ 285 R5_LOCKED, /* IO has been submitted on "req" */ 286 R5_DOUBLE_LOCKED,/* Cannot clear R5_LOCKED until 2 writes complete */ 287 R5_OVERWRITE, /* towrite covers whole page */ 288 /* and some that are internal to handle_stripe */ 289 R5_Insync, /* rdev && rdev->in_sync at start */ 290 R5_Wantread, /* want to schedule a read */ 291 R5_Wantwrite, 292 R5_Overlap, /* There is a pending overlapping request 293 * on this block */ 294 R5_ReadNoMerge, /* prevent bio from merging in block-layer */ 295 R5_ReadError, /* seen a read error here recently */ 296 R5_ReWrite, /* have tried to over-write the readerror */ 297 298 R5_Expanded, /* This block now has post-expand data */ 299 R5_Wantcompute, /* compute_block in progress treat as 300 * uptodate 301 */ 302 R5_Wantfill, /* dev->toread contains a bio that needs 303 * filling 304 */ 305 R5_Wantdrain, /* dev->towrite needs to be drained */ 306 R5_WantFUA, /* Write should be FUA */ 307 R5_SyncIO, /* The IO is sync */ 308 R5_WriteError, /* got a write error - need to record it */ 309 R5_MadeGood, /* A bad block has been fixed by writing to it */ 310 R5_ReadRepl, /* Will/did read from replacement rather than orig */ 311 R5_MadeGoodRepl,/* A bad block on the replacement device has been 312 * fixed by writing to it */ 313 R5_NeedReplace, /* This device has a replacement which is not 314 * up-to-date at this stripe. */ 315 R5_WantReplace, /* We need to update the replacement, we have read 316 * data in, and now is a good time to write it out. 317 */ 318 R5_Discard, /* Discard the stripe */ 319 R5_SkipCopy, /* Don't copy data from bio to stripe cache */ 320 R5_InJournal, /* data being written is in the journal device. 321 * if R5_InJournal is set for parity pd_idx, all the 322 * data and parity being written are in the journal 323 * device 324 */ 325 }; 326 327 /* 328 * Stripe state 329 */ 330 enum { 331 STRIPE_ACTIVE, 332 STRIPE_HANDLE, 333 STRIPE_SYNC_REQUESTED, 334 STRIPE_SYNCING, 335 STRIPE_INSYNC, 336 STRIPE_REPLACED, 337 STRIPE_PREREAD_ACTIVE, 338 STRIPE_DELAYED, 339 STRIPE_DEGRADED, 340 STRIPE_BIT_DELAY, 341 STRIPE_EXPANDING, 342 STRIPE_EXPAND_SOURCE, 343 STRIPE_EXPAND_READY, 344 STRIPE_IO_STARTED, /* do not count towards 'bypass_count' */ 345 STRIPE_FULL_WRITE, /* all blocks are set to be overwritten */ 346 STRIPE_BIOFILL_RUN, 347 STRIPE_COMPUTE_RUN, 348 STRIPE_OPS_REQ_PENDING, 349 STRIPE_ON_UNPLUG_LIST, 350 STRIPE_DISCARD, 351 STRIPE_ON_RELEASE_LIST, 352 STRIPE_BATCH_READY, 353 STRIPE_BATCH_ERR, 354 STRIPE_BITMAP_PENDING, /* Being added to bitmap, don't add 355 * to batch yet. 356 */ 357 STRIPE_LOG_TRAPPED, /* trapped into log (see raid5-cache.c) 358 * this bit is used in two scenarios: 359 * 360 * 1. write-out phase 361 * set in first entry of r5l_write_stripe 362 * clear in second entry of r5l_write_stripe 363 * used to bypass logic in handle_stripe 364 * 365 * 2. caching phase 366 * set in r5c_try_caching_write() 367 * clear when journal write is done 368 * used to initiate r5c_cache_data() 369 * also used to bypass logic in handle_stripe 370 */ 371 STRIPE_R5C_CACHING, /* the stripe is in caching phase 372 * see more detail in the raid5-cache.c 373 */ 374 STRIPE_R5C_PARTIAL_STRIPE, /* in r5c cache (to-be/being handled or 375 * in conf->r5c_partial_stripe_list) 376 */ 377 STRIPE_R5C_FULL_STRIPE, /* in r5c cache (to-be/being handled or 378 * in conf->r5c_full_stripe_list) 379 */ 380 STRIPE_R5C_PREFLUSH, /* need to flush journal device */ 381 }; 382 383 #define STRIPE_EXPAND_SYNC_FLAGS \ 384 ((1 << STRIPE_EXPAND_SOURCE) |\ 385 (1 << STRIPE_EXPAND_READY) |\ 386 (1 << STRIPE_EXPANDING) |\ 387 (1 << STRIPE_SYNC_REQUESTED)) 388 /* 389 * Operation request flags 390 */ 391 enum { 392 STRIPE_OP_BIOFILL, 393 STRIPE_OP_COMPUTE_BLK, 394 STRIPE_OP_PREXOR, 395 STRIPE_OP_BIODRAIN, 396 STRIPE_OP_RECONSTRUCT, 397 STRIPE_OP_CHECK, 398 }; 399 400 /* 401 * RAID parity calculation preferences 402 */ 403 enum { 404 PARITY_DISABLE_RMW = 0, 405 PARITY_ENABLE_RMW, 406 PARITY_PREFER_RMW, 407 }; 408 409 /* 410 * Pages requested from set_syndrome_sources() 411 */ 412 enum { 413 SYNDROME_SRC_ALL, 414 SYNDROME_SRC_WANT_DRAIN, 415 SYNDROME_SRC_WRITTEN, 416 }; 417 /* 418 * Plugging: 419 * 420 * To improve write throughput, we need to delay the handling of some 421 * stripes until there has been a chance that several write requests 422 * for the one stripe have all been collected. 423 * In particular, any write request that would require pre-reading 424 * is put on a "delayed" queue until there are no stripes currently 425 * in a pre-read phase. Further, if the "delayed" queue is empty when 426 * a stripe is put on it then we "plug" the queue and do not process it 427 * until an unplug call is made. (the unplug_io_fn() is called). 428 * 429 * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add 430 * it to the count of prereading stripes. 431 * When write is initiated, or the stripe refcnt == 0 (just in case) we 432 * clear the PREREAD_ACTIVE flag and decrement the count 433 * Whenever the 'handle' queue is empty and the device is not plugged, we 434 * move any strips from delayed to handle and clear the DELAYED flag and set 435 * PREREAD_ACTIVE. 436 * In stripe_handle, if we find pre-reading is necessary, we do it if 437 * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue. 438 * HANDLE gets cleared if stripe_handle leaves nothing locked. 439 */ 440 441 struct disk_info { 442 struct md_rdev *rdev, *replacement; 443 struct page *extra_page; /* extra page to use in prexor */ 444 }; 445 446 /* 447 * Stripe cache 448 */ 449 450 #define NR_STRIPES 256 451 #define STRIPE_SIZE PAGE_SIZE 452 #define STRIPE_SHIFT (PAGE_SHIFT - 9) 453 #define STRIPE_SECTORS (STRIPE_SIZE>>9) 454 #define IO_THRESHOLD 1 455 #define BYPASS_THRESHOLD 1 456 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) 457 #define HASH_MASK (NR_HASH - 1) 458 #define MAX_STRIPE_BATCH 8 459 460 /* bio's attached to a stripe+device for I/O are linked together in bi_sector 461 * order without overlap. There may be several bio's per stripe+device, and 462 * a bio could span several devices. 463 * When walking this list for a particular stripe+device, we must never proceed 464 * beyond a bio that extends past this device, as the next bio might no longer 465 * be valid. 466 * This function is used to determine the 'next' bio in the list, given the 467 * sector of the current stripe+device 468 */ 469 static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector) 470 { 471 int sectors = bio_sectors(bio); 472 473 if (bio->bi_iter.bi_sector + sectors < sector + STRIPE_SECTORS) 474 return bio->bi_next; 475 else 476 return NULL; 477 } 478 479 /* 480 * We maintain a biased count of active stripes in the bottom 16 bits of 481 * bi_phys_segments, and a count of processed stripes in the upper 16 bits 482 */ 483 static inline int raid5_bi_processed_stripes(struct bio *bio) 484 { 485 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments; 486 487 return (atomic_read(segments) >> 16) & 0xffff; 488 } 489 490 static inline int raid5_dec_bi_active_stripes(struct bio *bio) 491 { 492 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments; 493 494 return atomic_sub_return(1, segments) & 0xffff; 495 } 496 497 static inline void raid5_inc_bi_active_stripes(struct bio *bio) 498 { 499 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments; 500 501 atomic_inc(segments); 502 } 503 504 static inline void raid5_set_bi_processed_stripes(struct bio *bio, 505 unsigned int cnt) 506 { 507 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments; 508 int old, new; 509 510 do { 511 old = atomic_read(segments); 512 new = (old & 0xffff) | (cnt << 16); 513 } while (atomic_cmpxchg(segments, old, new) != old); 514 } 515 516 static inline void raid5_set_bi_stripes(struct bio *bio, unsigned int cnt) 517 { 518 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments; 519 520 atomic_set(segments, cnt); 521 } 522 523 /* NOTE NR_STRIPE_HASH_LOCKS must remain below 64. 524 * This is because we sometimes take all the spinlocks 525 * and creating that much locking depth can cause 526 * problems. 527 */ 528 #define NR_STRIPE_HASH_LOCKS 8 529 #define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1) 530 531 struct r5worker { 532 struct work_struct work; 533 struct r5worker_group *group; 534 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; 535 bool working; 536 }; 537 538 struct r5worker_group { 539 struct list_head handle_list; 540 struct r5conf *conf; 541 struct r5worker *workers; 542 int stripes_cnt; 543 }; 544 545 enum r5_cache_state { 546 R5_INACTIVE_BLOCKED, /* release of inactive stripes blocked, 547 * waiting for 25% to be free 548 */ 549 R5_ALLOC_MORE, /* It might help to allocate another 550 * stripe. 551 */ 552 R5_DID_ALLOC, /* A stripe was allocated, don't allocate 553 * more until at least one has been 554 * released. This avoids flooding 555 * the cache. 556 */ 557 R5C_LOG_TIGHT, /* log device space tight, need to 558 * prioritize stripes at last_checkpoint 559 */ 560 R5C_LOG_CRITICAL, /* log device is running out of space, 561 * only process stripes that are already 562 * occupying the log 563 */ 564 R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page 565 * for prexor 566 */ 567 }; 568 569 struct r5conf { 570 struct hlist_head *stripe_hashtbl; 571 /* only protect corresponding hash list and inactive_list */ 572 spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS]; 573 struct mddev *mddev; 574 int chunk_sectors; 575 int level, algorithm, rmw_level; 576 int max_degraded; 577 int raid_disks; 578 int max_nr_stripes; 579 int min_nr_stripes; 580 581 /* reshape_progress is the leading edge of a 'reshape' 582 * It has value MaxSector when no reshape is happening 583 * If delta_disks < 0, it is the last sector we started work on, 584 * else is it the next sector to work on. 585 */ 586 sector_t reshape_progress; 587 /* reshape_safe is the trailing edge of a reshape. We know that 588 * before (or after) this address, all reshape has completed. 589 */ 590 sector_t reshape_safe; 591 int previous_raid_disks; 592 int prev_chunk_sectors; 593 int prev_algo; 594 short generation; /* increments with every reshape */ 595 seqcount_t gen_lock; /* lock against generation changes */ 596 unsigned long reshape_checkpoint; /* Time we last updated 597 * metadata */ 598 long long min_offset_diff; /* minimum difference between 599 * data_offset and 600 * new_data_offset across all 601 * devices. May be negative, 602 * but is closest to zero. 603 */ 604 605 struct list_head handle_list; /* stripes needing handling */ 606 struct list_head hold_list; /* preread ready stripes */ 607 struct list_head delayed_list; /* stripes that have plugged requests */ 608 struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */ 609 struct bio *retry_read_aligned; /* currently retrying aligned bios */ 610 struct bio *retry_read_aligned_list; /* aligned bios retry list */ 611 atomic_t preread_active_stripes; /* stripes with scheduled io */ 612 atomic_t active_aligned_reads; 613 atomic_t pending_full_writes; /* full write backlog */ 614 int bypass_count; /* bypassed prereads */ 615 int bypass_threshold; /* preread nice */ 616 int skip_copy; /* Don't copy data from bio to stripe cache */ 617 struct list_head *last_hold; /* detect hold_list promotions */ 618 619 /* bios to have bi_end_io called after metadata is synced */ 620 struct bio_list return_bi; 621 622 atomic_t reshape_stripes; /* stripes with pending writes for reshape */ 623 /* unfortunately we need two cache names as we temporarily have 624 * two caches. 625 */ 626 int active_name; 627 char cache_name[2][32]; 628 struct kmem_cache *slab_cache; /* for allocating stripes */ 629 struct mutex cache_size_mutex; /* Protect changes to cache size */ 630 631 int seq_flush, seq_write; 632 int quiesce; 633 634 int fullsync; /* set to 1 if a full sync is needed, 635 * (fresh device added). 636 * Cleared when a sync completes. 637 */ 638 int recovery_disabled; 639 /* per cpu variables */ 640 struct raid5_percpu { 641 struct page *spare_page; /* Used when checking P/Q in raid6 */ 642 struct flex_array *scribble; /* space for constructing buffer 643 * lists and performing address 644 * conversions 645 */ 646 } __percpu *percpu; 647 int scribble_disks; 648 int scribble_sectors; 649 struct hlist_node node; 650 651 /* 652 * Free stripes pool 653 */ 654 atomic_t active_stripes; 655 struct list_head inactive_list[NR_STRIPE_HASH_LOCKS]; 656 657 atomic_t r5c_cached_full_stripes; 658 struct list_head r5c_full_stripe_list; 659 atomic_t r5c_cached_partial_stripes; 660 struct list_head r5c_partial_stripe_list; 661 662 atomic_t empty_inactive_list_nr; 663 struct llist_head released_stripes; 664 wait_queue_head_t wait_for_quiescent; 665 wait_queue_head_t wait_for_stripe; 666 wait_queue_head_t wait_for_overlap; 667 unsigned long cache_state; 668 struct shrinker shrinker; 669 int pool_size; /* number of disks in stripeheads in pool */ 670 spinlock_t device_lock; 671 struct disk_info *disks; 672 673 /* When taking over an array from a different personality, we store 674 * the new thread here until we fully activate the array. 675 */ 676 struct md_thread *thread; 677 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; 678 struct r5worker_group *worker_groups; 679 int group_cnt; 680 int worker_cnt_per_group; 681 struct r5l_log *log; 682 }; 683 684 685 /* 686 * Our supported algorithms 687 */ 688 #define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */ 689 #define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */ 690 #define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */ 691 #define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */ 692 693 /* Define non-rotating (raid4) algorithms. These allow 694 * conversion of raid4 to raid5. 695 */ 696 #define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */ 697 #define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */ 698 699 /* DDF RAID6 layouts differ from md/raid6 layouts in two ways. 700 * Firstly, the exact positioning of the parity block is slightly 701 * different between the 'LEFT_*' modes of md and the "_N_*" modes 702 * of DDF. 703 * Secondly, or order of datablocks over which the Q syndrome is computed 704 * is different. 705 * Consequently we have different layouts for DDF/raid6 than md/raid6. 706 * These layouts are from the DDFv1.2 spec. 707 * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but 708 * leaves RLQ=3 as 'Vendor Specific' 709 */ 710 711 #define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */ 712 #define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */ 713 #define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */ 714 715 /* For every RAID5 algorithm we define a RAID6 algorithm 716 * with exactly the same layout for data and parity, and 717 * with the Q block always on the last device (N-1). 718 * This allows trivial conversion from RAID5 to RAID6 719 */ 720 #define ALGORITHM_LEFT_ASYMMETRIC_6 16 721 #define ALGORITHM_RIGHT_ASYMMETRIC_6 17 722 #define ALGORITHM_LEFT_SYMMETRIC_6 18 723 #define ALGORITHM_RIGHT_SYMMETRIC_6 19 724 #define ALGORITHM_PARITY_0_6 20 725 #define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N 726 727 static inline int algorithm_valid_raid5(int layout) 728 { 729 return (layout >= 0) && 730 (layout <= 5); 731 } 732 static inline int algorithm_valid_raid6(int layout) 733 { 734 return (layout >= 0 && layout <= 5) 735 || 736 (layout >= 8 && layout <= 10) 737 || 738 (layout >= 16 && layout <= 20); 739 } 740 741 static inline int algorithm_is_DDF(int layout) 742 { 743 return layout >= 8 && layout <= 10; 744 } 745 746 extern void md_raid5_kick_device(struct r5conf *conf); 747 extern int raid5_set_cache_size(struct mddev *mddev, int size); 748 extern sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous); 749 extern void raid5_release_stripe(struct stripe_head *sh); 750 extern sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector, 751 int previous, int *dd_idx, 752 struct stripe_head *sh); 753 extern struct stripe_head * 754 raid5_get_active_stripe(struct r5conf *conf, sector_t sector, 755 int previous, int noblock, int noquiesce); 756 extern int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev); 757 extern void r5l_exit_log(struct r5l_log *log); 758 extern int r5l_write_stripe(struct r5l_log *log, struct stripe_head *head_sh); 759 extern void r5l_write_stripe_run(struct r5l_log *log); 760 extern void r5l_flush_stripe_to_raid(struct r5l_log *log); 761 extern void r5l_stripe_write_finished(struct stripe_head *sh); 762 extern int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio); 763 extern void r5l_quiesce(struct r5l_log *log, int state); 764 extern bool r5l_log_disk_error(struct r5conf *conf); 765 extern bool r5c_is_writeback(struct r5l_log *log); 766 extern int 767 r5c_try_caching_write(struct r5conf *conf, struct stripe_head *sh, 768 struct stripe_head_state *s, int disks); 769 extern void 770 r5c_finish_stripe_write_out(struct r5conf *conf, struct stripe_head *sh, 771 struct stripe_head_state *s); 772 extern void r5c_release_extra_page(struct stripe_head *sh); 773 extern void r5c_use_extra_page(struct stripe_head *sh); 774 extern void r5l_wake_reclaim(struct r5l_log *log, sector_t space); 775 extern void r5c_handle_cached_data_endio(struct r5conf *conf, 776 struct stripe_head *sh, int disks, struct bio_list *return_bi); 777 extern int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh, 778 struct stripe_head_state *s); 779 extern void r5c_make_stripe_write_out(struct stripe_head *sh); 780 extern void r5c_flush_cache(struct r5conf *conf, int num); 781 extern void r5c_check_stripe_cache_usage(struct r5conf *conf); 782 extern void r5c_check_cached_full_stripe(struct r5conf *conf); 783 extern struct md_sysfs_entry r5c_journal_mode; 784 #endif 785