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 #include <linux/local_lock.h> 8 9 /* 10 * 11 * Each stripe contains one buffer per device. Each buffer can be in 12 * one of a number of states stored in "flags". Changes between 13 * these states happen *almost* exclusively under the protection of the 14 * STRIPE_ACTIVE flag. Some very specific changes can happen in bi_end_io, and 15 * these are not protected by STRIPE_ACTIVE. 16 * 17 * The flag bits that are used to represent these states are: 18 * R5_UPTODATE and R5_LOCKED 19 * 20 * State Empty == !UPTODATE, !LOCK 21 * We have no data, and there is no active request 22 * State Want == !UPTODATE, LOCK 23 * A read request is being submitted for this block 24 * State Dirty == UPTODATE, LOCK 25 * Some new data is in this buffer, and it is being written out 26 * State Clean == UPTODATE, !LOCK 27 * We have valid data which is the same as on disc 28 * 29 * The possible state transitions are: 30 * 31 * Empty -> Want - on read or write to get old data for parity calc 32 * Empty -> Dirty - on compute_parity to satisfy write/sync request. 33 * Empty -> Clean - on compute_block when computing a block for failed drive 34 * Want -> Empty - on failed read 35 * Want -> Clean - on successful completion of read request 36 * Dirty -> Clean - on successful completion of write request 37 * Dirty -> Clean - on failed write 38 * Clean -> Dirty - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW) 39 * 40 * The Want->Empty, Want->Clean, Dirty->Clean, transitions 41 * all happen in b_end_io at interrupt time. 42 * Each sets the Uptodate bit before releasing the Lock bit. 43 * This leaves one multi-stage transition: 44 * Want->Dirty->Clean 45 * This is safe because thinking that a Clean buffer is actually dirty 46 * will at worst delay some action, and the stripe will be scheduled 47 * for attention after the transition is complete. 48 * 49 * There is one possibility that is not covered by these states. That 50 * is if one drive has failed and there is a spare being rebuilt. We 51 * can't distinguish between a clean block that has been generated 52 * from parity calculations, and a clean block that has been 53 * successfully written to the spare ( or to parity when resyncing). 54 * To distinguish these states we have a stripe bit STRIPE_INSYNC that 55 * is set whenever a write is scheduled to the spare, or to the parity 56 * disc if there is no spare. A sync request clears this bit, and 57 * when we find it set with no buffers locked, we know the sync is 58 * complete. 59 * 60 * Buffers for the md device that arrive via make_request are attached 61 * to the appropriate stripe in one of two lists linked on b_reqnext. 62 * One list (bh_read) for read requests, one (bh_write) for write. 63 * There should never be more than one buffer on the two lists 64 * together, but we are not guaranteed of that so we allow for more. 65 * 66 * If a buffer is on the read list when the associated cache buffer is 67 * Uptodate, the data is copied into the read buffer and it's b_end_io 68 * routine is called. This may happen in the end_request routine only 69 * if the buffer has just successfully been read. end_request should 70 * remove the buffers from the list and then set the Uptodate bit on 71 * the buffer. Other threads may do this only if they first check 72 * that the Uptodate bit is set. Once they have checked that they may 73 * take buffers off the read queue. 74 * 75 * When a buffer on the write list is committed for write it is copied 76 * into the cache buffer, which is then marked dirty, and moved onto a 77 * third list, the written list (bh_written). Once both the parity 78 * block and the cached buffer are successfully written, any buffer on 79 * a written list can be returned with b_end_io. 80 * 81 * The write list and read list both act as fifos. The read list, 82 * write list and written list are protected by the device_lock. 83 * The device_lock is only for list manipulations and will only be 84 * held for a very short time. It can be claimed from interrupts. 85 * 86 * 87 * Stripes in the stripe cache can be on one of two lists (or on 88 * neither). The "inactive_list" contains stripes which are not 89 * currently being used for any request. They can freely be reused 90 * for another stripe. The "handle_list" contains stripes that need 91 * to be handled in some way. Both of these are fifo queues. Each 92 * stripe is also (potentially) linked to a hash bucket in the hash 93 * table so that it can be found by sector number. Stripes that are 94 * not hashed must be on the inactive_list, and will normally be at 95 * the front. All stripes start life this way. 96 * 97 * The inactive_list, handle_list and hash bucket lists are all protected by the 98 * device_lock. 99 * - stripes have a reference counter. If count==0, they are on a list. 100 * - If a stripe might need handling, STRIPE_HANDLE is set. 101 * - When refcount reaches zero, then if STRIPE_HANDLE it is put on 102 * handle_list else inactive_list 103 * 104 * This, combined with the fact that STRIPE_HANDLE is only ever 105 * cleared while a stripe has a non-zero count means that if the 106 * refcount is 0 and STRIPE_HANDLE is set, then it is on the 107 * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then 108 * the stripe is on inactive_list. 109 * 110 * The possible transitions are: 111 * activate an unhashed/inactive stripe (get_active_stripe()) 112 * lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev 113 * activate a hashed, possibly active stripe (get_active_stripe()) 114 * lockdev check-hash if(!cnt++)unlink-stripe unlockdev 115 * attach a request to an active stripe (add_stripe_bh()) 116 * lockdev attach-buffer unlockdev 117 * handle a stripe (handle_stripe()) 118 * setSTRIPE_ACTIVE, clrSTRIPE_HANDLE ... 119 * (lockdev check-buffers unlockdev) .. 120 * change-state .. 121 * record io/ops needed clearSTRIPE_ACTIVE schedule io/ops 122 * release an active stripe (release_stripe()) 123 * lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev 124 * 125 * The refcount counts each thread that have activated the stripe, 126 * plus raid5d if it is handling it, plus one for each active request 127 * on a cached buffer, and plus one if the stripe is undergoing stripe 128 * operations. 129 * 130 * The stripe operations are: 131 * -copying data between the stripe cache and user application buffers 132 * -computing blocks to save a disk access, or to recover a missing block 133 * -updating the parity on a write operation (reconstruct write and 134 * read-modify-write) 135 * -checking parity correctness 136 * -running i/o to disk 137 * These operations are carried out by raid5_run_ops which uses the async_tx 138 * api to (optionally) offload operations to dedicated hardware engines. 139 * When requesting an operation handle_stripe sets the pending bit for the 140 * operation and increments the count. raid5_run_ops is then run whenever 141 * the count is non-zero. 142 * There are some critical dependencies between the operations that prevent some 143 * from being requested while another is in flight. 144 * 1/ Parity check operations destroy the in cache version of the parity block, 145 * so we prevent parity dependent operations like writes and compute_blocks 146 * from starting while a check is in progress. Some dma engines can perform 147 * the check without damaging the parity block, in these cases the parity 148 * block is re-marked up to date (assuming the check was successful) and is 149 * not re-read from disk. 150 * 2/ When a write operation is requested we immediately lock the affected 151 * blocks, and mark them as not up to date. This causes new read requests 152 * to be held off, as well as parity checks and compute block operations. 153 * 3/ Once a compute block operation has been requested handle_stripe treats 154 * that block as if it is up to date. raid5_run_ops guaruntees that any 155 * operation that is dependent on the compute block result is initiated after 156 * the compute block completes. 157 */ 158 159 /* 160 * Operations state - intermediate states that are visible outside of 161 * STRIPE_ACTIVE. 162 * In general _idle indicates nothing is running, _run indicates a data 163 * processing operation is active, and _result means the data processing result 164 * is stable and can be acted upon. For simple operations like biofill and 165 * compute that only have an _idle and _run state they are indicated with 166 * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN) 167 */ 168 /** 169 * enum check_states - handles syncing / repairing a stripe 170 * @check_state_idle - check operations are quiesced 171 * @check_state_run - check operation is running 172 * @check_state_result - set outside lock when check result is valid 173 * @check_state_compute_run - check failed and we are repairing 174 * @check_state_compute_result - set outside lock when compute result is valid 175 */ 176 enum check_states { 177 check_state_idle = 0, 178 check_state_run, /* xor parity check */ 179 check_state_run_q, /* q-parity check */ 180 check_state_run_pq, /* pq dual parity check */ 181 check_state_check_result, 182 check_state_compute_run, /* parity repair */ 183 check_state_compute_result, 184 }; 185 186 /** 187 * enum reconstruct_states - handles writing or expanding a stripe 188 */ 189 enum reconstruct_states { 190 reconstruct_state_idle = 0, 191 reconstruct_state_prexor_drain_run, /* prexor-write */ 192 reconstruct_state_drain_run, /* write */ 193 reconstruct_state_run, /* expand */ 194 reconstruct_state_prexor_drain_result, 195 reconstruct_state_drain_result, 196 reconstruct_state_result, 197 }; 198 199 #define DEFAULT_STRIPE_SIZE 4096 200 struct stripe_head { 201 struct hlist_node hash; 202 struct list_head lru; /* inactive_list or handle_list */ 203 struct llist_node release_list; 204 struct r5conf *raid_conf; 205 short generation; /* increments with every 206 * reshape */ 207 sector_t sector; /* sector of this row */ 208 short pd_idx; /* parity disk index */ 209 short qd_idx; /* 'Q' disk index for raid6 */ 210 short ddf_layout;/* use DDF ordering to calculate Q */ 211 short hash_lock_index; 212 unsigned long state; /* state flags */ 213 atomic_t count; /* nr of active thread/requests */ 214 int bm_seq; /* sequence number for bitmap flushes */ 215 int disks; /* disks in stripe */ 216 int overwrite_disks; /* total overwrite disks in stripe, 217 * this is only checked when stripe 218 * has STRIPE_BATCH_READY 219 */ 220 enum check_states check_state; 221 enum reconstruct_states reconstruct_state; 222 spinlock_t stripe_lock; 223 int cpu; 224 struct r5worker_group *group; 225 226 struct stripe_head *batch_head; /* protected by stripe lock */ 227 spinlock_t batch_lock; /* only header's lock is useful */ 228 struct list_head batch_list; /* protected by head's batch lock*/ 229 230 union { 231 struct r5l_io_unit *log_io; 232 struct ppl_io_unit *ppl_io; 233 }; 234 235 struct list_head log_list; 236 sector_t log_start; /* first meta block on the journal */ 237 struct list_head r5c; /* for r5c_cache->stripe_in_journal */ 238 239 struct page *ppl_page; /* partial parity of this stripe */ 240 /** 241 * struct stripe_operations 242 * @target - STRIPE_OP_COMPUTE_BLK target 243 * @target2 - 2nd compute target in the raid6 case 244 * @zero_sum_result - P and Q verification flags 245 * @request - async service request flags for raid_run_ops 246 */ 247 struct stripe_operations { 248 int target, target2; 249 enum sum_check_flags zero_sum_result; 250 } ops; 251 252 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE 253 /* These pages will be used by bios in dev[i] */ 254 struct page **pages; 255 int nr_pages; /* page array size */ 256 int stripes_per_page; 257 #endif 258 struct r5dev { 259 /* rreq and rvec are used for the replacement device when 260 * writing data to both devices. 261 */ 262 struct bio req, rreq; 263 struct bio_vec vec, rvec; 264 struct page *page, *orig_page; 265 unsigned int offset; /* offset of the page */ 266 struct bio *toread, *read, *towrite, *written; 267 sector_t sector; /* sector of this page */ 268 unsigned long flags; 269 u32 log_checksum; 270 unsigned short write_hint; 271 } dev[1]; /* allocated with extra space depending of RAID geometry */ 272 }; 273 274 /* stripe_head_state - collects and tracks the dynamic state of a stripe_head 275 * for handle_stripe. 276 */ 277 struct stripe_head_state { 278 /* 'syncing' means that we need to read all devices, either 279 * to check/correct parity, or to reconstruct a missing device. 280 * 'replacing' means we are replacing one or more drives and 281 * the source is valid at this point so we don't need to 282 * read all devices, just the replacement targets. 283 */ 284 int syncing, expanding, expanded, replacing; 285 int locked, uptodate, to_read, to_write, failed, written; 286 int to_fill, compute, req_compute, non_overwrite; 287 int injournal, just_cached; 288 int failed_num[2]; 289 int p_failed, q_failed; 290 int dec_preread_active; 291 unsigned long ops_request; 292 293 struct md_rdev *blocked_rdev; 294 int handle_bad_blocks; 295 int log_failed; 296 int waiting_extra_page; 297 }; 298 299 /* Flags for struct r5dev.flags */ 300 enum r5dev_flags { 301 R5_UPTODATE, /* page contains current data */ 302 R5_LOCKED, /* IO has been submitted on "req" */ 303 R5_DOUBLE_LOCKED,/* Cannot clear R5_LOCKED until 2 writes complete */ 304 R5_OVERWRITE, /* towrite covers whole page */ 305 /* and some that are internal to handle_stripe */ 306 R5_Insync, /* rdev && rdev->in_sync at start */ 307 R5_Wantread, /* want to schedule a read */ 308 R5_Wantwrite, 309 R5_Overlap, /* There is a pending overlapping request 310 * on this block */ 311 R5_ReadNoMerge, /* prevent bio from merging in block-layer */ 312 R5_ReadError, /* seen a read error here recently */ 313 R5_ReWrite, /* have tried to over-write the readerror */ 314 315 R5_Expanded, /* This block now has post-expand data */ 316 R5_Wantcompute, /* compute_block in progress treat as 317 * uptodate 318 */ 319 R5_Wantfill, /* dev->toread contains a bio that needs 320 * filling 321 */ 322 R5_Wantdrain, /* dev->towrite needs to be drained */ 323 R5_WantFUA, /* Write should be FUA */ 324 R5_SyncIO, /* The IO is sync */ 325 R5_WriteError, /* got a write error - need to record it */ 326 R5_MadeGood, /* A bad block has been fixed by writing to it */ 327 R5_ReadRepl, /* Will/did read from replacement rather than orig */ 328 R5_MadeGoodRepl,/* A bad block on the replacement device has been 329 * fixed by writing to it */ 330 R5_NeedReplace, /* This device has a replacement which is not 331 * up-to-date at this stripe. */ 332 R5_WantReplace, /* We need to update the replacement, we have read 333 * data in, and now is a good time to write it out. 334 */ 335 R5_Discard, /* Discard the stripe */ 336 R5_SkipCopy, /* Don't copy data from bio to stripe cache */ 337 R5_InJournal, /* data being written is in the journal device. 338 * if R5_InJournal is set for parity pd_idx, all the 339 * data and parity being written are in the journal 340 * device 341 */ 342 R5_OrigPageUPTDODATE, /* with write back cache, we read old data into 343 * dev->orig_page for prexor. When this flag is 344 * set, orig_page contains latest data in the 345 * raid disk. 346 */ 347 }; 348 349 /* 350 * Stripe state 351 */ 352 enum { 353 STRIPE_ACTIVE, 354 STRIPE_HANDLE, 355 STRIPE_SYNC_REQUESTED, 356 STRIPE_SYNCING, 357 STRIPE_INSYNC, 358 STRIPE_REPLACED, 359 STRIPE_PREREAD_ACTIVE, 360 STRIPE_DELAYED, 361 STRIPE_DEGRADED, 362 STRIPE_BIT_DELAY, 363 STRIPE_EXPANDING, 364 STRIPE_EXPAND_SOURCE, 365 STRIPE_EXPAND_READY, 366 STRIPE_IO_STARTED, /* do not count towards 'bypass_count' */ 367 STRIPE_FULL_WRITE, /* all blocks are set to be overwritten */ 368 STRIPE_BIOFILL_RUN, 369 STRIPE_COMPUTE_RUN, 370 STRIPE_ON_UNPLUG_LIST, 371 STRIPE_DISCARD, 372 STRIPE_ON_RELEASE_LIST, 373 STRIPE_BATCH_READY, 374 STRIPE_BATCH_ERR, 375 STRIPE_BITMAP_PENDING, /* Being added to bitmap, don't add 376 * to batch yet. 377 */ 378 STRIPE_LOG_TRAPPED, /* trapped into log (see raid5-cache.c) 379 * this bit is used in two scenarios: 380 * 381 * 1. write-out phase 382 * set in first entry of r5l_write_stripe 383 * clear in second entry of r5l_write_stripe 384 * used to bypass logic in handle_stripe 385 * 386 * 2. caching phase 387 * set in r5c_try_caching_write() 388 * clear when journal write is done 389 * used to initiate r5c_cache_data() 390 * also used to bypass logic in handle_stripe 391 */ 392 STRIPE_R5C_CACHING, /* the stripe is in caching phase 393 * see more detail in the raid5-cache.c 394 */ 395 STRIPE_R5C_PARTIAL_STRIPE, /* in r5c cache (to-be/being handled or 396 * in conf->r5c_partial_stripe_list) 397 */ 398 STRIPE_R5C_FULL_STRIPE, /* in r5c cache (to-be/being handled or 399 * in conf->r5c_full_stripe_list) 400 */ 401 STRIPE_R5C_PREFLUSH, /* need to flush journal device */ 402 }; 403 404 #define STRIPE_EXPAND_SYNC_FLAGS \ 405 ((1 << STRIPE_EXPAND_SOURCE) |\ 406 (1 << STRIPE_EXPAND_READY) |\ 407 (1 << STRIPE_EXPANDING) |\ 408 (1 << STRIPE_SYNC_REQUESTED)) 409 /* 410 * Operation request flags 411 */ 412 enum { 413 STRIPE_OP_BIOFILL, 414 STRIPE_OP_COMPUTE_BLK, 415 STRIPE_OP_PREXOR, 416 STRIPE_OP_BIODRAIN, 417 STRIPE_OP_RECONSTRUCT, 418 STRIPE_OP_CHECK, 419 STRIPE_OP_PARTIAL_PARITY, 420 }; 421 422 /* 423 * RAID parity calculation preferences 424 */ 425 enum { 426 PARITY_DISABLE_RMW = 0, 427 PARITY_ENABLE_RMW, 428 PARITY_PREFER_RMW, 429 }; 430 431 /* 432 * Pages requested from set_syndrome_sources() 433 */ 434 enum { 435 SYNDROME_SRC_ALL, 436 SYNDROME_SRC_WANT_DRAIN, 437 SYNDROME_SRC_WRITTEN, 438 }; 439 /* 440 * Plugging: 441 * 442 * To improve write throughput, we need to delay the handling of some 443 * stripes until there has been a chance that several write requests 444 * for the one stripe have all been collected. 445 * In particular, any write request that would require pre-reading 446 * is put on a "delayed" queue until there are no stripes currently 447 * in a pre-read phase. Further, if the "delayed" queue is empty when 448 * a stripe is put on it then we "plug" the queue and do not process it 449 * until an unplug call is made. (the unplug_io_fn() is called). 450 * 451 * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add 452 * it to the count of prereading stripes. 453 * When write is initiated, or the stripe refcnt == 0 (just in case) we 454 * clear the PREREAD_ACTIVE flag and decrement the count 455 * Whenever the 'handle' queue is empty and the device is not plugged, we 456 * move any strips from delayed to handle and clear the DELAYED flag and set 457 * PREREAD_ACTIVE. 458 * In stripe_handle, if we find pre-reading is necessary, we do it if 459 * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue. 460 * HANDLE gets cleared if stripe_handle leaves nothing locked. 461 */ 462 463 /* Note: disk_info.rdev can be set to NULL asynchronously by raid5_remove_disk. 464 * There are three safe ways to access disk_info.rdev. 465 * 1/ when holding mddev->reconfig_mutex 466 * 2/ when resync/recovery/reshape is known to be happening - i.e. in code that 467 * is called as part of performing resync/recovery/reshape. 468 * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer 469 * and if it is non-NULL, increment rdev->nr_pending before dropping the RCU 470 * lock. 471 * When .rdev is set to NULL, the nr_pending count checked again and if 472 * it has been incremented, the pointer is put back in .rdev. 473 */ 474 475 struct disk_info { 476 struct md_rdev *rdev, *replacement; 477 struct page *extra_page; /* extra page to use in prexor */ 478 }; 479 480 /* 481 * Stripe cache 482 */ 483 484 #define NR_STRIPES 256 485 486 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE 487 #define STRIPE_SIZE PAGE_SIZE 488 #define STRIPE_SHIFT (PAGE_SHIFT - 9) 489 #define STRIPE_SECTORS (STRIPE_SIZE>>9) 490 #endif 491 492 #define IO_THRESHOLD 1 493 #define BYPASS_THRESHOLD 1 494 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) 495 #define HASH_MASK (NR_HASH - 1) 496 #define MAX_STRIPE_BATCH 8 497 498 /* NOTE NR_STRIPE_HASH_LOCKS must remain below 64. 499 * This is because we sometimes take all the spinlocks 500 * and creating that much locking depth can cause 501 * problems. 502 */ 503 #define NR_STRIPE_HASH_LOCKS 8 504 #define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1) 505 506 struct r5worker { 507 struct work_struct work; 508 struct r5worker_group *group; 509 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; 510 bool working; 511 }; 512 513 struct r5worker_group { 514 struct list_head handle_list; 515 struct list_head loprio_list; 516 struct r5conf *conf; 517 struct r5worker *workers; 518 int stripes_cnt; 519 }; 520 521 /* 522 * r5c journal modes of the array: write-back or write-through. 523 * write-through mode has identical behavior as existing log only 524 * implementation. 525 */ 526 enum r5c_journal_mode { 527 R5C_JOURNAL_MODE_WRITE_THROUGH = 0, 528 R5C_JOURNAL_MODE_WRITE_BACK = 1, 529 }; 530 531 enum r5_cache_state { 532 R5_INACTIVE_BLOCKED, /* release of inactive stripes blocked, 533 * waiting for 25% to be free 534 */ 535 R5_ALLOC_MORE, /* It might help to allocate another 536 * stripe. 537 */ 538 R5_DID_ALLOC, /* A stripe was allocated, don't allocate 539 * more until at least one has been 540 * released. This avoids flooding 541 * the cache. 542 */ 543 R5C_LOG_TIGHT, /* log device space tight, need to 544 * prioritize stripes at last_checkpoint 545 */ 546 R5C_LOG_CRITICAL, /* log device is running out of space, 547 * only process stripes that are already 548 * occupying the log 549 */ 550 R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page 551 * for prexor 552 */ 553 }; 554 555 #define PENDING_IO_MAX 512 556 #define PENDING_IO_ONE_FLUSH 128 557 struct r5pending_data { 558 struct list_head sibling; 559 sector_t sector; /* stripe sector */ 560 struct bio_list bios; 561 }; 562 563 struct r5conf { 564 struct hlist_head *stripe_hashtbl; 565 /* only protect corresponding hash list and inactive_list */ 566 spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS]; 567 struct mddev *mddev; 568 int chunk_sectors; 569 int level, algorithm, rmw_level; 570 int max_degraded; 571 int raid_disks; 572 int max_nr_stripes; 573 int min_nr_stripes; 574 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE 575 unsigned long stripe_size; 576 unsigned int stripe_shift; 577 unsigned long stripe_sectors; 578 #endif 579 580 /* reshape_progress is the leading edge of a 'reshape' 581 * It has value MaxSector when no reshape is happening 582 * If delta_disks < 0, it is the last sector we started work on, 583 * else is it the next sector to work on. 584 */ 585 sector_t reshape_progress; 586 /* reshape_safe is the trailing edge of a reshape. We know that 587 * before (or after) this address, all reshape has completed. 588 */ 589 sector_t reshape_safe; 590 int previous_raid_disks; 591 int prev_chunk_sectors; 592 int prev_algo; 593 short generation; /* increments with every reshape */ 594 seqcount_spinlock_t gen_lock; /* lock against generation changes */ 595 unsigned long reshape_checkpoint; /* Time we last updated 596 * metadata */ 597 long long min_offset_diff; /* minimum difference between 598 * data_offset and 599 * new_data_offset across all 600 * devices. May be negative, 601 * but is closest to zero. 602 */ 603 604 struct list_head handle_list; /* stripes needing handling */ 605 struct list_head loprio_list; /* low priority stripes */ 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 unsigned int retry_read_offset; /* sector offset into retry_read_aligned */ 611 struct bio *retry_read_aligned_list; /* aligned bios retry list */ 612 atomic_t preread_active_stripes; /* stripes with scheduled io */ 613 atomic_t active_aligned_reads; 614 atomic_t pending_full_writes; /* full write backlog */ 615 int bypass_count; /* bypassed prereads */ 616 int bypass_threshold; /* preread nice */ 617 int skip_copy; /* Don't copy data from bio to stripe cache */ 618 struct list_head *last_hold; /* detect hold_list promotions */ 619 620 atomic_t reshape_stripes; /* stripes with pending writes for reshape */ 621 /* unfortunately we need two cache names as we temporarily have 622 * two caches. 623 */ 624 int active_name; 625 char cache_name[2][32]; 626 struct kmem_cache *slab_cache; /* for allocating stripes */ 627 struct mutex cache_size_mutex; /* Protect changes to cache size */ 628 629 int seq_flush, seq_write; 630 int quiesce; 631 632 int fullsync; /* set to 1 if a full sync is needed, 633 * (fresh device added). 634 * Cleared when a sync completes. 635 */ 636 int recovery_disabled; 637 /* per cpu variables */ 638 struct raid5_percpu { 639 struct page *spare_page; /* Used when checking P/Q in raid6 */ 640 void *scribble; /* space for constructing buffer 641 * lists and performing address 642 * conversions 643 */ 644 int scribble_obj_size; 645 local_lock_t lock; 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 atomic_t r5c_flushing_full_stripes; 662 atomic_t r5c_flushing_partial_stripes; 663 664 atomic_t empty_inactive_list_nr; 665 struct llist_head released_stripes; 666 wait_queue_head_t wait_for_quiescent; 667 wait_queue_head_t wait_for_stripe; 668 wait_queue_head_t wait_for_overlap; 669 unsigned long cache_state; 670 struct shrinker shrinker; 671 int pool_size; /* number of disks in stripeheads in pool */ 672 spinlock_t device_lock; 673 struct disk_info *disks; 674 struct bio_set bio_split; 675 676 /* When taking over an array from a different personality, we store 677 * the new thread here until we fully activate the array. 678 */ 679 struct md_thread *thread; 680 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; 681 struct r5worker_group *worker_groups; 682 int group_cnt; 683 int worker_cnt_per_group; 684 struct r5l_log *log; 685 void *log_private; 686 687 spinlock_t pending_bios_lock; 688 bool batch_bio_dispatch; 689 struct r5pending_data *pending_data; 690 struct list_head free_list; 691 struct list_head pending_list; 692 int pending_data_cnt; 693 struct r5pending_data *next_pending_data; 694 }; 695 696 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE 697 #define RAID5_STRIPE_SIZE(conf) STRIPE_SIZE 698 #define RAID5_STRIPE_SHIFT(conf) STRIPE_SHIFT 699 #define RAID5_STRIPE_SECTORS(conf) STRIPE_SECTORS 700 #else 701 #define RAID5_STRIPE_SIZE(conf) ((conf)->stripe_size) 702 #define RAID5_STRIPE_SHIFT(conf) ((conf)->stripe_shift) 703 #define RAID5_STRIPE_SECTORS(conf) ((conf)->stripe_sectors) 704 #endif 705 706 /* bio's attached to a stripe+device for I/O are linked together in bi_sector 707 * order without overlap. There may be several bio's per stripe+device, and 708 * a bio could span several devices. 709 * When walking this list for a particular stripe+device, we must never proceed 710 * beyond a bio that extends past this device, as the next bio might no longer 711 * be valid. 712 * This function is used to determine the 'next' bio in the list, given the 713 * sector of the current stripe+device 714 */ 715 static inline struct bio *r5_next_bio(struct r5conf *conf, struct bio *bio, sector_t sector) 716 { 717 if (bio_end_sector(bio) < sector + RAID5_STRIPE_SECTORS(conf)) 718 return bio->bi_next; 719 else 720 return NULL; 721 } 722 723 /* 724 * Our supported algorithms 725 */ 726 #define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */ 727 #define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */ 728 #define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */ 729 #define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */ 730 731 /* Define non-rotating (raid4) algorithms. These allow 732 * conversion of raid4 to raid5. 733 */ 734 #define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */ 735 #define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */ 736 737 /* DDF RAID6 layouts differ from md/raid6 layouts in two ways. 738 * Firstly, the exact positioning of the parity block is slightly 739 * different between the 'LEFT_*' modes of md and the "_N_*" modes 740 * of DDF. 741 * Secondly, or order of datablocks over which the Q syndrome is computed 742 * is different. 743 * Consequently we have different layouts for DDF/raid6 than md/raid6. 744 * These layouts are from the DDFv1.2 spec. 745 * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but 746 * leaves RLQ=3 as 'Vendor Specific' 747 */ 748 749 #define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */ 750 #define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */ 751 #define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */ 752 753 /* For every RAID5 algorithm we define a RAID6 algorithm 754 * with exactly the same layout for data and parity, and 755 * with the Q block always on the last device (N-1). 756 * This allows trivial conversion from RAID5 to RAID6 757 */ 758 #define ALGORITHM_LEFT_ASYMMETRIC_6 16 759 #define ALGORITHM_RIGHT_ASYMMETRIC_6 17 760 #define ALGORITHM_LEFT_SYMMETRIC_6 18 761 #define ALGORITHM_RIGHT_SYMMETRIC_6 19 762 #define ALGORITHM_PARITY_0_6 20 763 #define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N 764 765 static inline int algorithm_valid_raid5(int layout) 766 { 767 return (layout >= 0) && 768 (layout <= 5); 769 } 770 static inline int algorithm_valid_raid6(int layout) 771 { 772 return (layout >= 0 && layout <= 5) 773 || 774 (layout >= 8 && layout <= 10) 775 || 776 (layout >= 16 && layout <= 20); 777 } 778 779 static inline int algorithm_is_DDF(int layout) 780 { 781 return layout >= 8 && layout <= 10; 782 } 783 784 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE 785 /* 786 * Return offset of the corresponding page for r5dev. 787 */ 788 static inline int raid5_get_page_offset(struct stripe_head *sh, int disk_idx) 789 { 790 return (disk_idx % sh->stripes_per_page) * RAID5_STRIPE_SIZE(sh->raid_conf); 791 } 792 793 /* 794 * Return corresponding page address for r5dev. 795 */ 796 static inline struct page * 797 raid5_get_dev_page(struct stripe_head *sh, int disk_idx) 798 { 799 return sh->pages[disk_idx / sh->stripes_per_page]; 800 } 801 #endif 802 803 extern void md_raid5_kick_device(struct r5conf *conf); 804 extern int raid5_set_cache_size(struct mddev *mddev, int size); 805 extern sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous); 806 extern void raid5_release_stripe(struct stripe_head *sh); 807 extern sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector, 808 int previous, int *dd_idx, 809 struct stripe_head *sh); 810 extern struct stripe_head * 811 raid5_get_active_stripe(struct r5conf *conf, sector_t sector, 812 int previous, int noblock, int noquiesce); 813 extern int raid5_calc_degraded(struct r5conf *conf); 814 extern int r5c_journal_mode_set(struct mddev *mddev, int journal_mode); 815 #endif 816