1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _RAID5_H 3 #define _RAID5_H 4 5 #include <linux/raid/xor.h> 6 #include <linux/dmaengine.h> 7 8 /* 9 * 10 * Each stripe contains one buffer per device. Each buffer can be in 11 * one of a number of states stored in "flags". Changes between 12 * these states happen *almost* exclusively under the protection of the 13 * STRIPE_ACTIVE flag. Some very specific changes can happen in bi_end_io, and 14 * these are not protected by STRIPE_ACTIVE. 15 * 16 * The flag bits that are used to represent these states are: 17 * R5_UPTODATE and R5_LOCKED 18 * 19 * State Empty == !UPTODATE, !LOCK 20 * We have no data, and there is no active request 21 * State Want == !UPTODATE, LOCK 22 * A read request is being submitted for this block 23 * State Dirty == UPTODATE, LOCK 24 * Some new data is in this buffer, and it is being written out 25 * State Clean == UPTODATE, !LOCK 26 * We have valid data which is the same as on disc 27 * 28 * The possible state transitions are: 29 * 30 * Empty -> Want - on read or write to get old data for parity calc 31 * Empty -> Dirty - on compute_parity to satisfy write/sync request. 32 * Empty -> Clean - on compute_block when computing a block for failed drive 33 * Want -> Empty - on failed read 34 * Want -> Clean - on successful completion of read request 35 * Dirty -> Clean - on successful completion of write request 36 * Dirty -> Clean - on failed write 37 * Clean -> Dirty - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW) 38 * 39 * The Want->Empty, Want->Clean, Dirty->Clean, transitions 40 * all happen in b_end_io at interrupt time. 41 * Each sets the Uptodate bit before releasing the Lock bit. 42 * This leaves one multi-stage transition: 43 * Want->Dirty->Clean 44 * This is safe because thinking that a Clean buffer is actually dirty 45 * will at worst delay some action, and the stripe will be scheduled 46 * for attention after the transition is complete. 47 * 48 * There is one possibility that is not covered by these states. That 49 * is if one drive has failed and there is a spare being rebuilt. We 50 * can't distinguish between a clean block that has been generated 51 * from parity calculations, and a clean block that has been 52 * successfully written to the spare ( or to parity when resyncing). 53 * To distinguish these states we have a stripe bit STRIPE_INSYNC that 54 * is set whenever a write is scheduled to the spare, or to the parity 55 * disc if there is no spare. A sync request clears this bit, and 56 * when we find it set with no buffers locked, we know the sync is 57 * complete. 58 * 59 * Buffers for the md device that arrive via make_request are attached 60 * to the appropriate stripe in one of two lists linked on b_reqnext. 61 * One list (bh_read) for read requests, one (bh_write) for write. 62 * There should never be more than one buffer on the two lists 63 * together, but we are not guaranteed of that so we allow for more. 64 * 65 * If a buffer is on the read list when the associated cache buffer is 66 * Uptodate, the data is copied into the read buffer and it's b_end_io 67 * routine is called. This may happen in the end_request routine only 68 * if the buffer has just successfully been read. end_request should 69 * remove the buffers from the list and then set the Uptodate bit on 70 * the buffer. Other threads may do this only if they first check 71 * that the Uptodate bit is set. Once they have checked that they may 72 * take buffers off the read queue. 73 * 74 * When a buffer on the write list is committed for write it is copied 75 * into the cache buffer, which is then marked dirty, and moved onto a 76 * third list, the written list (bh_written). Once both the parity 77 * block and the cached buffer are successfully written, any buffer on 78 * a written list can be returned with b_end_io. 79 * 80 * The write list and read list both act as fifos. The read list, 81 * write list and written list are protected by the device_lock. 82 * The device_lock is only for list manipulations and will only be 83 * held for a very short time. It can be claimed from interrupts. 84 * 85 * 86 * Stripes in the stripe cache can be on one of two lists (or on 87 * neither). The "inactive_list" contains stripes which are not 88 * currently being used for any request. They can freely be reused 89 * for another stripe. The "handle_list" contains stripes that need 90 * to be handled in some way. Both of these are fifo queues. Each 91 * stripe is also (potentially) linked to a hash bucket in the hash 92 * table so that it can be found by sector number. Stripes that are 93 * not hashed must be on the inactive_list, and will normally be at 94 * the front. All stripes start life this way. 95 * 96 * The inactive_list, handle_list and hash bucket lists are all protected by the 97 * device_lock. 98 * - stripes have a reference counter. If count==0, they are on a list. 99 * - If a stripe might need handling, STRIPE_HANDLE is set. 100 * - When refcount reaches zero, then if STRIPE_HANDLE it is put on 101 * handle_list else inactive_list 102 * 103 * This, combined with the fact that STRIPE_HANDLE is only ever 104 * cleared while a stripe has a non-zero count means that if the 105 * refcount is 0 and STRIPE_HANDLE is set, then it is on the 106 * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then 107 * the stripe is on inactive_list. 108 * 109 * The possible transitions are: 110 * activate an unhashed/inactive stripe (get_active_stripe()) 111 * lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev 112 * activate a hashed, possibly active stripe (get_active_stripe()) 113 * lockdev check-hash if(!cnt++)unlink-stripe unlockdev 114 * attach a request to an active stripe (add_stripe_bh()) 115 * lockdev attach-buffer unlockdev 116 * handle a stripe (handle_stripe()) 117 * setSTRIPE_ACTIVE, clrSTRIPE_HANDLE ... 118 * (lockdev check-buffers unlockdev) .. 119 * change-state .. 120 * record io/ops needed clearSTRIPE_ACTIVE schedule io/ops 121 * release an active stripe (release_stripe()) 122 * lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev 123 * 124 * The refcount counts each thread that have activated the stripe, 125 * plus raid5d if it is handling it, plus one for each active request 126 * on a cached buffer, and plus one if the stripe is undergoing stripe 127 * operations. 128 * 129 * The stripe operations are: 130 * -copying data between the stripe cache and user application buffers 131 * -computing blocks to save a disk access, or to recover a missing block 132 * -updating the parity on a write operation (reconstruct write and 133 * read-modify-write) 134 * -checking parity correctness 135 * -running i/o to disk 136 * These operations are carried out by raid5_run_ops which uses the async_tx 137 * api to (optionally) offload operations to dedicated hardware engines. 138 * When requesting an operation handle_stripe sets the pending bit for the 139 * operation and increments the count. raid5_run_ops is then run whenever 140 * the count is non-zero. 141 * There are some critical dependencies between the operations that prevent some 142 * from being requested while another is in flight. 143 * 1/ Parity check operations destroy the in cache version of the parity block, 144 * so we prevent parity dependent operations like writes and compute_blocks 145 * from starting while a check is in progress. Some dma engines can perform 146 * the check without damaging the parity block, in these cases the parity 147 * block is re-marked up to date (assuming the check was successful) and is 148 * not re-read from disk. 149 * 2/ When a write operation is requested we immediately lock the affected 150 * blocks, and mark them as not up to date. This causes new read requests 151 * to be held off, as well as parity checks and compute block operations. 152 * 3/ Once a compute block operation has been requested handle_stripe treats 153 * that block as if it is up to date. raid5_run_ops guaruntees that any 154 * operation that is dependent on the compute block result is initiated after 155 * the compute block completes. 156 */ 157 158 /* 159 * Operations state - intermediate states that are visible outside of 160 * STRIPE_ACTIVE. 161 * In general _idle indicates nothing is running, _run indicates a data 162 * processing operation is active, and _result means the data processing result 163 * is stable and can be acted upon. For simple operations like biofill and 164 * compute that only have an _idle and _run state they are indicated with 165 * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN) 166 */ 167 /** 168 * enum check_states - handles syncing / repairing a stripe 169 * @check_state_idle - check operations are quiesced 170 * @check_state_run - check operation is running 171 * @check_state_result - set outside lock when check result is valid 172 * @check_state_compute_run - check failed and we are repairing 173 * @check_state_compute_result - set outside lock when compute result is valid 174 */ 175 enum check_states { 176 check_state_idle = 0, 177 check_state_run, /* xor parity check */ 178 check_state_run_q, /* q-parity check */ 179 check_state_run_pq, /* pq dual parity check */ 180 check_state_check_result, 181 check_state_compute_run, /* parity repair */ 182 check_state_compute_result, 183 }; 184 185 /** 186 * enum reconstruct_states - handles writing or expanding a stripe 187 */ 188 enum reconstruct_states { 189 reconstruct_state_idle = 0, 190 reconstruct_state_prexor_drain_run, /* prexor-write */ 191 reconstruct_state_drain_run, /* write */ 192 reconstruct_state_run, /* expand */ 193 reconstruct_state_prexor_drain_result, 194 reconstruct_state_drain_result, 195 reconstruct_state_result, 196 }; 197 198 struct stripe_head { 199 struct hlist_node hash; 200 struct list_head lru; /* inactive_list or handle_list */ 201 struct llist_node release_list; 202 struct r5conf *raid_conf; 203 short generation; /* increments with every 204 * reshape */ 205 sector_t sector; /* sector of this row */ 206 short pd_idx; /* parity disk index */ 207 short qd_idx; /* 'Q' disk index for raid6 */ 208 short ddf_layout;/* use DDF ordering to calculate Q */ 209 short hash_lock_index; 210 unsigned long state; /* state flags */ 211 atomic_t count; /* nr of active thread/requests */ 212 int bm_seq; /* sequence number for bitmap flushes */ 213 int disks; /* disks in stripe */ 214 int overwrite_disks; /* total overwrite disks in stripe, 215 * this is only checked when stripe 216 * has STRIPE_BATCH_READY 217 */ 218 enum check_states check_state; 219 enum reconstruct_states reconstruct_state; 220 spinlock_t stripe_lock; 221 int cpu; 222 struct r5worker_group *group; 223 224 struct stripe_head *batch_head; /* protected by stripe lock */ 225 spinlock_t batch_lock; /* only header's lock is useful */ 226 struct list_head batch_list; /* protected by head's batch lock*/ 227 228 union { 229 struct r5l_io_unit *log_io; 230 struct ppl_io_unit *ppl_io; 231 }; 232 233 struct list_head log_list; 234 sector_t log_start; /* first meta block on the journal */ 235 struct list_head r5c; /* for r5c_cache->stripe_in_journal */ 236 237 struct page *ppl_page; /* partial parity of this stripe */ 238 /** 239 * struct stripe_operations 240 * @target - STRIPE_OP_COMPUTE_BLK target 241 * @target2 - 2nd compute target in the raid6 case 242 * @zero_sum_result - P and Q verification flags 243 * @request - async service request flags for raid_run_ops 244 */ 245 struct stripe_operations { 246 int target, target2; 247 enum sum_check_flags zero_sum_result; 248 } ops; 249 struct r5dev { 250 /* rreq and rvec are used for the replacement device when 251 * writing data to both devices. 252 */ 253 struct bio req, rreq; 254 struct bio_vec vec, rvec; 255 struct page *page, *orig_page; 256 struct bio *toread, *read, *towrite, *written; 257 sector_t sector; /* sector of this page */ 258 unsigned long flags; 259 u32 log_checksum; 260 unsigned short write_hint; 261 } dev[1]; /* allocated with extra space depending of RAID geometry */ 262 }; 263 264 /* stripe_head_state - collects and tracks the dynamic state of a stripe_head 265 * for handle_stripe. 266 */ 267 struct stripe_head_state { 268 /* 'syncing' means that we need to read all devices, either 269 * to check/correct parity, or to reconstruct a missing device. 270 * 'replacing' means we are replacing one or more drives and 271 * the source is valid at this point so we don't need to 272 * read all devices, just the replacement targets. 273 */ 274 int syncing, expanding, expanded, replacing; 275 int locked, uptodate, to_read, to_write, failed, written; 276 int to_fill, compute, req_compute, non_overwrite; 277 int injournal, just_cached; 278 int failed_num[2]; 279 int p_failed, q_failed; 280 int dec_preread_active; 281 unsigned long ops_request; 282 283 struct md_rdev *blocked_rdev; 284 int handle_bad_blocks; 285 int log_failed; 286 int waiting_extra_page; 287 }; 288 289 /* Flags for struct r5dev.flags */ 290 enum r5dev_flags { 291 R5_UPTODATE, /* page contains current data */ 292 R5_LOCKED, /* IO has been submitted on "req" */ 293 R5_DOUBLE_LOCKED,/* Cannot clear R5_LOCKED until 2 writes complete */ 294 R5_OVERWRITE, /* towrite covers whole page */ 295 /* and some that are internal to handle_stripe */ 296 R5_Insync, /* rdev && rdev->in_sync at start */ 297 R5_Wantread, /* want to schedule a read */ 298 R5_Wantwrite, 299 R5_Overlap, /* There is a pending overlapping request 300 * on this block */ 301 R5_ReadNoMerge, /* prevent bio from merging in block-layer */ 302 R5_ReadError, /* seen a read error here recently */ 303 R5_ReWrite, /* have tried to over-write the readerror */ 304 305 R5_Expanded, /* This block now has post-expand data */ 306 R5_Wantcompute, /* compute_block in progress treat as 307 * uptodate 308 */ 309 R5_Wantfill, /* dev->toread contains a bio that needs 310 * filling 311 */ 312 R5_Wantdrain, /* dev->towrite needs to be drained */ 313 R5_WantFUA, /* Write should be FUA */ 314 R5_SyncIO, /* The IO is sync */ 315 R5_WriteError, /* got a write error - need to record it */ 316 R5_MadeGood, /* A bad block has been fixed by writing to it */ 317 R5_ReadRepl, /* Will/did read from replacement rather than orig */ 318 R5_MadeGoodRepl,/* A bad block on the replacement device has been 319 * fixed by writing to it */ 320 R5_NeedReplace, /* This device has a replacement which is not 321 * up-to-date at this stripe. */ 322 R5_WantReplace, /* We need to update the replacement, we have read 323 * data in, and now is a good time to write it out. 324 */ 325 R5_Discard, /* Discard the stripe */ 326 R5_SkipCopy, /* Don't copy data from bio to stripe cache */ 327 R5_InJournal, /* data being written is in the journal device. 328 * if R5_InJournal is set for parity pd_idx, all the 329 * data and parity being written are in the journal 330 * device 331 */ 332 R5_OrigPageUPTDODATE, /* with write back cache, we read old data into 333 * dev->orig_page for prexor. When this flag is 334 * set, orig_page contains latest data in the 335 * raid disk. 336 */ 337 }; 338 339 /* 340 * Stripe state 341 */ 342 enum { 343 STRIPE_ACTIVE, 344 STRIPE_HANDLE, 345 STRIPE_SYNC_REQUESTED, 346 STRIPE_SYNCING, 347 STRIPE_INSYNC, 348 STRIPE_REPLACED, 349 STRIPE_PREREAD_ACTIVE, 350 STRIPE_DELAYED, 351 STRIPE_DEGRADED, 352 STRIPE_BIT_DELAY, 353 STRIPE_EXPANDING, 354 STRIPE_EXPAND_SOURCE, 355 STRIPE_EXPAND_READY, 356 STRIPE_IO_STARTED, /* do not count towards 'bypass_count' */ 357 STRIPE_FULL_WRITE, /* all blocks are set to be overwritten */ 358 STRIPE_BIOFILL_RUN, 359 STRIPE_COMPUTE_RUN, 360 STRIPE_ON_UNPLUG_LIST, 361 STRIPE_DISCARD, 362 STRIPE_ON_RELEASE_LIST, 363 STRIPE_BATCH_READY, 364 STRIPE_BATCH_ERR, 365 STRIPE_BITMAP_PENDING, /* Being added to bitmap, don't add 366 * to batch yet. 367 */ 368 STRIPE_LOG_TRAPPED, /* trapped into log (see raid5-cache.c) 369 * this bit is used in two scenarios: 370 * 371 * 1. write-out phase 372 * set in first entry of r5l_write_stripe 373 * clear in second entry of r5l_write_stripe 374 * used to bypass logic in handle_stripe 375 * 376 * 2. caching phase 377 * set in r5c_try_caching_write() 378 * clear when journal write is done 379 * used to initiate r5c_cache_data() 380 * also used to bypass logic in handle_stripe 381 */ 382 STRIPE_R5C_CACHING, /* the stripe is in caching phase 383 * see more detail in the raid5-cache.c 384 */ 385 STRIPE_R5C_PARTIAL_STRIPE, /* in r5c cache (to-be/being handled or 386 * in conf->r5c_partial_stripe_list) 387 */ 388 STRIPE_R5C_FULL_STRIPE, /* in r5c cache (to-be/being handled or 389 * in conf->r5c_full_stripe_list) 390 */ 391 STRIPE_R5C_PREFLUSH, /* need to flush journal device */ 392 }; 393 394 #define STRIPE_EXPAND_SYNC_FLAGS \ 395 ((1 << STRIPE_EXPAND_SOURCE) |\ 396 (1 << STRIPE_EXPAND_READY) |\ 397 (1 << STRIPE_EXPANDING) |\ 398 (1 << STRIPE_SYNC_REQUESTED)) 399 /* 400 * Operation request flags 401 */ 402 enum { 403 STRIPE_OP_BIOFILL, 404 STRIPE_OP_COMPUTE_BLK, 405 STRIPE_OP_PREXOR, 406 STRIPE_OP_BIODRAIN, 407 STRIPE_OP_RECONSTRUCT, 408 STRIPE_OP_CHECK, 409 STRIPE_OP_PARTIAL_PARITY, 410 }; 411 412 /* 413 * RAID parity calculation preferences 414 */ 415 enum { 416 PARITY_DISABLE_RMW = 0, 417 PARITY_ENABLE_RMW, 418 PARITY_PREFER_RMW, 419 }; 420 421 /* 422 * Pages requested from set_syndrome_sources() 423 */ 424 enum { 425 SYNDROME_SRC_ALL, 426 SYNDROME_SRC_WANT_DRAIN, 427 SYNDROME_SRC_WRITTEN, 428 }; 429 /* 430 * Plugging: 431 * 432 * To improve write throughput, we need to delay the handling of some 433 * stripes until there has been a chance that several write requests 434 * for the one stripe have all been collected. 435 * In particular, any write request that would require pre-reading 436 * is put on a "delayed" queue until there are no stripes currently 437 * in a pre-read phase. Further, if the "delayed" queue is empty when 438 * a stripe is put on it then we "plug" the queue and do not process it 439 * until an unplug call is made. (the unplug_io_fn() is called). 440 * 441 * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add 442 * it to the count of prereading stripes. 443 * When write is initiated, or the stripe refcnt == 0 (just in case) we 444 * clear the PREREAD_ACTIVE flag and decrement the count 445 * Whenever the 'handle' queue is empty and the device is not plugged, we 446 * move any strips from delayed to handle and clear the DELAYED flag and set 447 * PREREAD_ACTIVE. 448 * In stripe_handle, if we find pre-reading is necessary, we do it if 449 * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue. 450 * HANDLE gets cleared if stripe_handle leaves nothing locked. 451 */ 452 453 /* Note: disk_info.rdev can be set to NULL asynchronously by raid5_remove_disk. 454 * There are three safe ways to access disk_info.rdev. 455 * 1/ when holding mddev->reconfig_mutex 456 * 2/ when resync/recovery/reshape is known to be happening - i.e. in code that 457 * is called as part of performing resync/recovery/reshape. 458 * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer 459 * and if it is non-NULL, increment rdev->nr_pending before dropping the RCU 460 * lock. 461 * When .rdev is set to NULL, the nr_pending count checked again and if 462 * it has been incremented, the pointer is put back in .rdev. 463 */ 464 465 struct disk_info { 466 struct md_rdev *rdev, *replacement; 467 struct page *extra_page; /* extra page to use in prexor */ 468 }; 469 470 /* 471 * Stripe cache 472 */ 473 474 #define NR_STRIPES 256 475 #define DEFAULT_STRIPE_SIZE 4096 476 477 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE 478 #define STRIPE_SIZE PAGE_SIZE 479 #define STRIPE_SHIFT (PAGE_SHIFT - 9) 480 #define STRIPE_SECTORS (STRIPE_SIZE>>9) 481 #endif 482 483 #define IO_THRESHOLD 1 484 #define BYPASS_THRESHOLD 1 485 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) 486 #define HASH_MASK (NR_HASH - 1) 487 #define MAX_STRIPE_BATCH 8 488 489 /* NOTE NR_STRIPE_HASH_LOCKS must remain below 64. 490 * This is because we sometimes take all the spinlocks 491 * and creating that much locking depth can cause 492 * problems. 493 */ 494 #define NR_STRIPE_HASH_LOCKS 8 495 #define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1) 496 497 struct r5worker { 498 struct work_struct work; 499 struct r5worker_group *group; 500 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; 501 bool working; 502 }; 503 504 struct r5worker_group { 505 struct list_head handle_list; 506 struct list_head loprio_list; 507 struct r5conf *conf; 508 struct r5worker *workers; 509 int stripes_cnt; 510 }; 511 512 /* 513 * r5c journal modes of the array: write-back or write-through. 514 * write-through mode has identical behavior as existing log only 515 * implementation. 516 */ 517 enum r5c_journal_mode { 518 R5C_JOURNAL_MODE_WRITE_THROUGH = 0, 519 R5C_JOURNAL_MODE_WRITE_BACK = 1, 520 }; 521 522 enum r5_cache_state { 523 R5_INACTIVE_BLOCKED, /* release of inactive stripes blocked, 524 * waiting for 25% to be free 525 */ 526 R5_ALLOC_MORE, /* It might help to allocate another 527 * stripe. 528 */ 529 R5_DID_ALLOC, /* A stripe was allocated, don't allocate 530 * more until at least one has been 531 * released. This avoids flooding 532 * the cache. 533 */ 534 R5C_LOG_TIGHT, /* log device space tight, need to 535 * prioritize stripes at last_checkpoint 536 */ 537 R5C_LOG_CRITICAL, /* log device is running out of space, 538 * only process stripes that are already 539 * occupying the log 540 */ 541 R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page 542 * for prexor 543 */ 544 }; 545 546 #define PENDING_IO_MAX 512 547 #define PENDING_IO_ONE_FLUSH 128 548 struct r5pending_data { 549 struct list_head sibling; 550 sector_t sector; /* stripe sector */ 551 struct bio_list bios; 552 }; 553 554 struct r5conf { 555 struct hlist_head *stripe_hashtbl; 556 /* only protect corresponding hash list and inactive_list */ 557 spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS]; 558 struct mddev *mddev; 559 int chunk_sectors; 560 int level, algorithm, rmw_level; 561 int max_degraded; 562 int raid_disks; 563 int max_nr_stripes; 564 int min_nr_stripes; 565 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE 566 unsigned long stripe_size; 567 unsigned int stripe_shift; 568 unsigned long stripe_sectors; 569 #endif 570 571 /* reshape_progress is the leading edge of a 'reshape' 572 * It has value MaxSector when no reshape is happening 573 * If delta_disks < 0, it is the last sector we started work on, 574 * else is it the next sector to work on. 575 */ 576 sector_t reshape_progress; 577 /* reshape_safe is the trailing edge of a reshape. We know that 578 * before (or after) this address, all reshape has completed. 579 */ 580 sector_t reshape_safe; 581 int previous_raid_disks; 582 int prev_chunk_sectors; 583 int prev_algo; 584 short generation; /* increments with every reshape */ 585 seqcount_spinlock_t gen_lock; /* lock against generation changes */ 586 unsigned long reshape_checkpoint; /* Time we last updated 587 * metadata */ 588 long long min_offset_diff; /* minimum difference between 589 * data_offset and 590 * new_data_offset across all 591 * devices. May be negative, 592 * but is closest to zero. 593 */ 594 595 struct list_head handle_list; /* stripes needing handling */ 596 struct list_head loprio_list; /* low priority stripes */ 597 struct list_head hold_list; /* preread ready stripes */ 598 struct list_head delayed_list; /* stripes that have plugged requests */ 599 struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */ 600 struct bio *retry_read_aligned; /* currently retrying aligned bios */ 601 unsigned int retry_read_offset; /* sector offset into retry_read_aligned */ 602 struct bio *retry_read_aligned_list; /* aligned bios retry list */ 603 atomic_t preread_active_stripes; /* stripes with scheduled io */ 604 atomic_t active_aligned_reads; 605 atomic_t pending_full_writes; /* full write backlog */ 606 int bypass_count; /* bypassed prereads */ 607 int bypass_threshold; /* preread nice */ 608 int skip_copy; /* Don't copy data from bio to stripe cache */ 609 struct list_head *last_hold; /* detect hold_list promotions */ 610 611 atomic_t reshape_stripes; /* stripes with pending writes for reshape */ 612 /* unfortunately we need two cache names as we temporarily have 613 * two caches. 614 */ 615 int active_name; 616 char cache_name[2][32]; 617 struct kmem_cache *slab_cache; /* for allocating stripes */ 618 struct mutex cache_size_mutex; /* Protect changes to cache size */ 619 620 int seq_flush, seq_write; 621 int quiesce; 622 623 int fullsync; /* set to 1 if a full sync is needed, 624 * (fresh device added). 625 * Cleared when a sync completes. 626 */ 627 int recovery_disabled; 628 /* per cpu variables */ 629 struct raid5_percpu { 630 struct page *spare_page; /* Used when checking P/Q in raid6 */ 631 void *scribble; /* space for constructing buffer 632 * lists and performing address 633 * conversions 634 */ 635 int scribble_obj_size; 636 } __percpu *percpu; 637 int scribble_disks; 638 int scribble_sectors; 639 struct hlist_node node; 640 641 /* 642 * Free stripes pool 643 */ 644 atomic_t active_stripes; 645 struct list_head inactive_list[NR_STRIPE_HASH_LOCKS]; 646 647 atomic_t r5c_cached_full_stripes; 648 struct list_head r5c_full_stripe_list; 649 atomic_t r5c_cached_partial_stripes; 650 struct list_head r5c_partial_stripe_list; 651 atomic_t r5c_flushing_full_stripes; 652 atomic_t r5c_flushing_partial_stripes; 653 654 atomic_t empty_inactive_list_nr; 655 struct llist_head released_stripes; 656 wait_queue_head_t wait_for_quiescent; 657 wait_queue_head_t wait_for_stripe; 658 wait_queue_head_t wait_for_overlap; 659 unsigned long cache_state; 660 struct shrinker shrinker; 661 int pool_size; /* number of disks in stripeheads in pool */ 662 spinlock_t device_lock; 663 struct disk_info *disks; 664 struct bio_set bio_split; 665 666 /* When taking over an array from a different personality, we store 667 * the new thread here until we fully activate the array. 668 */ 669 struct md_thread *thread; 670 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; 671 struct r5worker_group *worker_groups; 672 int group_cnt; 673 int worker_cnt_per_group; 674 struct r5l_log *log; 675 void *log_private; 676 677 spinlock_t pending_bios_lock; 678 bool batch_bio_dispatch; 679 struct r5pending_data *pending_data; 680 struct list_head free_list; 681 struct list_head pending_list; 682 int pending_data_cnt; 683 struct r5pending_data *next_pending_data; 684 }; 685 686 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE 687 #define RAID5_STRIPE_SIZE(conf) STRIPE_SIZE 688 #define RAID5_STRIPE_SHIFT(conf) STRIPE_SHIFT 689 #define RAID5_STRIPE_SECTORS(conf) STRIPE_SECTORS 690 #else 691 #define RAID5_STRIPE_SIZE(conf) ((conf)->stripe_size) 692 #define RAID5_STRIPE_SHIFT(conf) ((conf)->stripe_shift) 693 #define RAID5_STRIPE_SECTORS(conf) ((conf)->stripe_sectors) 694 #endif 695 696 /* bio's attached to a stripe+device for I/O are linked together in bi_sector 697 * order without overlap. There may be several bio's per stripe+device, and 698 * a bio could span several devices. 699 * When walking this list for a particular stripe+device, we must never proceed 700 * beyond a bio that extends past this device, as the next bio might no longer 701 * be valid. 702 * This function is used to determine the 'next' bio in the list, given the 703 * sector of the current stripe+device 704 */ 705 static inline struct bio *r5_next_bio(struct r5conf *conf, struct bio *bio, sector_t sector) 706 { 707 if (bio_end_sector(bio) < sector + RAID5_STRIPE_SECTORS(conf)) 708 return bio->bi_next; 709 else 710 return NULL; 711 } 712 713 /* 714 * Our supported algorithms 715 */ 716 #define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */ 717 #define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */ 718 #define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */ 719 #define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */ 720 721 /* Define non-rotating (raid4) algorithms. These allow 722 * conversion of raid4 to raid5. 723 */ 724 #define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */ 725 #define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */ 726 727 /* DDF RAID6 layouts differ from md/raid6 layouts in two ways. 728 * Firstly, the exact positioning of the parity block is slightly 729 * different between the 'LEFT_*' modes of md and the "_N_*" modes 730 * of DDF. 731 * Secondly, or order of datablocks over which the Q syndrome is computed 732 * is different. 733 * Consequently we have different layouts for DDF/raid6 than md/raid6. 734 * These layouts are from the DDFv1.2 spec. 735 * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but 736 * leaves RLQ=3 as 'Vendor Specific' 737 */ 738 739 #define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */ 740 #define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */ 741 #define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */ 742 743 /* For every RAID5 algorithm we define a RAID6 algorithm 744 * with exactly the same layout for data and parity, and 745 * with the Q block always on the last device (N-1). 746 * This allows trivial conversion from RAID5 to RAID6 747 */ 748 #define ALGORITHM_LEFT_ASYMMETRIC_6 16 749 #define ALGORITHM_RIGHT_ASYMMETRIC_6 17 750 #define ALGORITHM_LEFT_SYMMETRIC_6 18 751 #define ALGORITHM_RIGHT_SYMMETRIC_6 19 752 #define ALGORITHM_PARITY_0_6 20 753 #define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N 754 755 static inline int algorithm_valid_raid5(int layout) 756 { 757 return (layout >= 0) && 758 (layout <= 5); 759 } 760 static inline int algorithm_valid_raid6(int layout) 761 { 762 return (layout >= 0 && layout <= 5) 763 || 764 (layout >= 8 && layout <= 10) 765 || 766 (layout >= 16 && layout <= 20); 767 } 768 769 static inline int algorithm_is_DDF(int layout) 770 { 771 return layout >= 8 && layout <= 10; 772 } 773 774 extern void md_raid5_kick_device(struct r5conf *conf); 775 extern int raid5_set_cache_size(struct mddev *mddev, int size); 776 extern sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous); 777 extern void raid5_release_stripe(struct stripe_head *sh); 778 extern sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector, 779 int previous, int *dd_idx, 780 struct stripe_head *sh); 781 extern struct stripe_head * 782 raid5_get_active_stripe(struct r5conf *conf, sector_t sector, 783 int previous, int noblock, int noquiesce); 784 extern int raid5_calc_degraded(struct r5conf *conf); 785 extern int r5c_journal_mode_set(struct mddev *mddev, int journal_mode); 786 #endif 787