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 /** 230 * struct stripe_operations 231 * @target - STRIPE_OP_COMPUTE_BLK target 232 * @target2 - 2nd compute target in the raid6 case 233 * @zero_sum_result - P and Q verification flags 234 * @request - async service request flags for raid_run_ops 235 */ 236 struct stripe_operations { 237 int target, target2; 238 enum sum_check_flags zero_sum_result; 239 } ops; 240 struct r5dev { 241 /* rreq and rvec are used for the replacement device when 242 * writing data to both devices. 243 */ 244 struct bio req, rreq; 245 struct bio_vec vec, rvec; 246 struct page *page, *orig_page; 247 struct bio *toread, *read, *towrite, *written; 248 sector_t sector; /* sector of this page */ 249 unsigned long flags; 250 u32 log_checksum; 251 } dev[1]; /* allocated with extra space depending of RAID geometry */ 252 }; 253 254 /* stripe_head_state - collects and tracks the dynamic state of a stripe_head 255 * for handle_stripe. 256 */ 257 struct stripe_head_state { 258 /* 'syncing' means that we need to read all devices, either 259 * to check/correct parity, or to reconstruct a missing device. 260 * 'replacing' means we are replacing one or more drives and 261 * the source is valid at this point so we don't need to 262 * read all devices, just the replacement targets. 263 */ 264 int syncing, expanding, expanded, replacing; 265 int locked, uptodate, to_read, to_write, failed, written; 266 int to_fill, compute, req_compute, non_overwrite; 267 int failed_num[2]; 268 int p_failed, q_failed; 269 int dec_preread_active; 270 unsigned long ops_request; 271 272 struct bio_list return_bi; 273 struct md_rdev *blocked_rdev; 274 int handle_bad_blocks; 275 int log_failed; 276 }; 277 278 /* Flags for struct r5dev.flags */ 279 enum r5dev_flags { 280 R5_UPTODATE, /* page contains current data */ 281 R5_LOCKED, /* IO has been submitted on "req" */ 282 R5_DOUBLE_LOCKED,/* Cannot clear R5_LOCKED until 2 writes complete */ 283 R5_OVERWRITE, /* towrite covers whole page */ 284 /* and some that are internal to handle_stripe */ 285 R5_Insync, /* rdev && rdev->in_sync at start */ 286 R5_Wantread, /* want to schedule a read */ 287 R5_Wantwrite, 288 R5_Overlap, /* There is a pending overlapping request 289 * on this block */ 290 R5_ReadNoMerge, /* prevent bio from merging in block-layer */ 291 R5_ReadError, /* seen a read error here recently */ 292 R5_ReWrite, /* have tried to over-write the readerror */ 293 294 R5_Expanded, /* This block now has post-expand data */ 295 R5_Wantcompute, /* compute_block in progress treat as 296 * uptodate 297 */ 298 R5_Wantfill, /* dev->toread contains a bio that needs 299 * filling 300 */ 301 R5_Wantdrain, /* dev->towrite needs to be drained */ 302 R5_WantFUA, /* Write should be FUA */ 303 R5_SyncIO, /* The IO is sync */ 304 R5_WriteError, /* got a write error - need to record it */ 305 R5_MadeGood, /* A bad block has been fixed by writing to it */ 306 R5_ReadRepl, /* Will/did read from replacement rather than orig */ 307 R5_MadeGoodRepl,/* A bad block on the replacement device has been 308 * fixed by writing to it */ 309 R5_NeedReplace, /* This device has a replacement which is not 310 * up-to-date at this stripe. */ 311 R5_WantReplace, /* We need to update the replacement, we have read 312 * data in, and now is a good time to write it out. 313 */ 314 R5_Discard, /* Discard the stripe */ 315 R5_SkipCopy, /* Don't copy data from bio to stripe cache */ 316 }; 317 318 /* 319 * Stripe state 320 */ 321 enum { 322 STRIPE_ACTIVE, 323 STRIPE_HANDLE, 324 STRIPE_SYNC_REQUESTED, 325 STRIPE_SYNCING, 326 STRIPE_INSYNC, 327 STRIPE_REPLACED, 328 STRIPE_PREREAD_ACTIVE, 329 STRIPE_DELAYED, 330 STRIPE_DEGRADED, 331 STRIPE_BIT_DELAY, 332 STRIPE_EXPANDING, 333 STRIPE_EXPAND_SOURCE, 334 STRIPE_EXPAND_READY, 335 STRIPE_IO_STARTED, /* do not count towards 'bypass_count' */ 336 STRIPE_FULL_WRITE, /* all blocks are set to be overwritten */ 337 STRIPE_BIOFILL_RUN, 338 STRIPE_COMPUTE_RUN, 339 STRIPE_OPS_REQ_PENDING, 340 STRIPE_ON_UNPLUG_LIST, 341 STRIPE_DISCARD, 342 STRIPE_ON_RELEASE_LIST, 343 STRIPE_BATCH_READY, 344 STRIPE_BATCH_ERR, 345 STRIPE_BITMAP_PENDING, /* Being added to bitmap, don't add 346 * to batch yet. 347 */ 348 STRIPE_LOG_TRAPPED, /* trapped into log */ 349 }; 350 351 #define STRIPE_EXPAND_SYNC_FLAGS \ 352 ((1 << STRIPE_EXPAND_SOURCE) |\ 353 (1 << STRIPE_EXPAND_READY) |\ 354 (1 << STRIPE_EXPANDING) |\ 355 (1 << STRIPE_SYNC_REQUESTED)) 356 /* 357 * Operation request flags 358 */ 359 enum { 360 STRIPE_OP_BIOFILL, 361 STRIPE_OP_COMPUTE_BLK, 362 STRIPE_OP_PREXOR, 363 STRIPE_OP_BIODRAIN, 364 STRIPE_OP_RECONSTRUCT, 365 STRIPE_OP_CHECK, 366 }; 367 368 /* 369 * RAID parity calculation preferences 370 */ 371 enum { 372 PARITY_DISABLE_RMW = 0, 373 PARITY_ENABLE_RMW, 374 PARITY_PREFER_RMW, 375 }; 376 377 /* 378 * Pages requested from set_syndrome_sources() 379 */ 380 enum { 381 SYNDROME_SRC_ALL, 382 SYNDROME_SRC_WANT_DRAIN, 383 SYNDROME_SRC_WRITTEN, 384 }; 385 /* 386 * Plugging: 387 * 388 * To improve write throughput, we need to delay the handling of some 389 * stripes until there has been a chance that several write requests 390 * for the one stripe have all been collected. 391 * In particular, any write request that would require pre-reading 392 * is put on a "delayed" queue until there are no stripes currently 393 * in a pre-read phase. Further, if the "delayed" queue is empty when 394 * a stripe is put on it then we "plug" the queue and do not process it 395 * until an unplug call is made. (the unplug_io_fn() is called). 396 * 397 * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add 398 * it to the count of prereading stripes. 399 * When write is initiated, or the stripe refcnt == 0 (just in case) we 400 * clear the PREREAD_ACTIVE flag and decrement the count 401 * Whenever the 'handle' queue is empty and the device is not plugged, we 402 * move any strips from delayed to handle and clear the DELAYED flag and set 403 * PREREAD_ACTIVE. 404 * In stripe_handle, if we find pre-reading is necessary, we do it if 405 * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue. 406 * HANDLE gets cleared if stripe_handle leaves nothing locked. 407 */ 408 409 struct disk_info { 410 struct md_rdev *rdev, *replacement; 411 }; 412 413 /* NOTE NR_STRIPE_HASH_LOCKS must remain below 64. 414 * This is because we sometimes take all the spinlocks 415 * and creating that much locking depth can cause 416 * problems. 417 */ 418 #define NR_STRIPE_HASH_LOCKS 8 419 #define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1) 420 421 struct r5worker { 422 struct work_struct work; 423 struct r5worker_group *group; 424 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; 425 bool working; 426 }; 427 428 struct r5worker_group { 429 struct list_head handle_list; 430 struct r5conf *conf; 431 struct r5worker *workers; 432 int stripes_cnt; 433 }; 434 435 struct r5conf { 436 struct hlist_head *stripe_hashtbl; 437 /* only protect corresponding hash list and inactive_list */ 438 spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS]; 439 struct mddev *mddev; 440 int chunk_sectors; 441 int level, algorithm, rmw_level; 442 int max_degraded; 443 int raid_disks; 444 int max_nr_stripes; 445 int min_nr_stripes; 446 447 /* reshape_progress is the leading edge of a 'reshape' 448 * It has value MaxSector when no reshape is happening 449 * If delta_disks < 0, it is the last sector we started work on, 450 * else is it the next sector to work on. 451 */ 452 sector_t reshape_progress; 453 /* reshape_safe is the trailing edge of a reshape. We know that 454 * before (or after) this address, all reshape has completed. 455 */ 456 sector_t reshape_safe; 457 int previous_raid_disks; 458 int prev_chunk_sectors; 459 int prev_algo; 460 short generation; /* increments with every reshape */ 461 seqcount_t gen_lock; /* lock against generation changes */ 462 unsigned long reshape_checkpoint; /* Time we last updated 463 * metadata */ 464 long long min_offset_diff; /* minimum difference between 465 * data_offset and 466 * new_data_offset across all 467 * devices. May be negative, 468 * but is closest to zero. 469 */ 470 471 struct list_head handle_list; /* stripes needing handling */ 472 struct list_head hold_list; /* preread ready stripes */ 473 struct list_head delayed_list; /* stripes that have plugged requests */ 474 struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */ 475 struct bio *retry_read_aligned; /* currently retrying aligned bios */ 476 struct bio *retry_read_aligned_list; /* aligned bios retry list */ 477 atomic_t preread_active_stripes; /* stripes with scheduled io */ 478 atomic_t active_aligned_reads; 479 atomic_t pending_full_writes; /* full write backlog */ 480 int bypass_count; /* bypassed prereads */ 481 int bypass_threshold; /* preread nice */ 482 int skip_copy; /* Don't copy data from bio to stripe cache */ 483 struct list_head *last_hold; /* detect hold_list promotions */ 484 485 /* bios to have bi_end_io called after metadata is synced */ 486 struct bio_list return_bi; 487 488 atomic_t reshape_stripes; /* stripes with pending writes for reshape */ 489 /* unfortunately we need two cache names as we temporarily have 490 * two caches. 491 */ 492 int active_name; 493 char cache_name[2][32]; 494 struct kmem_cache *slab_cache; /* for allocating stripes */ 495 struct mutex cache_size_mutex; /* Protect changes to cache size */ 496 497 int seq_flush, seq_write; 498 int quiesce; 499 500 int fullsync; /* set to 1 if a full sync is needed, 501 * (fresh device added). 502 * Cleared when a sync completes. 503 */ 504 int recovery_disabled; 505 /* per cpu variables */ 506 struct raid5_percpu { 507 struct page *spare_page; /* Used when checking P/Q in raid6 */ 508 struct flex_array *scribble; /* space for constructing buffer 509 * lists and performing address 510 * conversions 511 */ 512 } __percpu *percpu; 513 int scribble_disks; 514 int scribble_sectors; 515 struct hlist_node node; 516 517 /* 518 * Free stripes pool 519 */ 520 atomic_t active_stripes; 521 struct list_head inactive_list[NR_STRIPE_HASH_LOCKS]; 522 atomic_t empty_inactive_list_nr; 523 struct llist_head released_stripes; 524 wait_queue_head_t wait_for_quiescent; 525 wait_queue_head_t wait_for_stripe; 526 wait_queue_head_t wait_for_overlap; 527 unsigned long cache_state; 528 #define R5_INACTIVE_BLOCKED 1 /* release of inactive stripes blocked, 529 * waiting for 25% to be free 530 */ 531 #define R5_ALLOC_MORE 2 /* It might help to allocate another 532 * stripe. 533 */ 534 #define R5_DID_ALLOC 4 /* A stripe was allocated, don't allocate 535 * more until at least one has been 536 * released. This avoids flooding 537 * the cache. 538 */ 539 struct shrinker shrinker; 540 int pool_size; /* number of disks in stripeheads in pool */ 541 spinlock_t device_lock; 542 struct disk_info *disks; 543 544 /* When taking over an array from a different personality, we store 545 * the new thread here until we fully activate the array. 546 */ 547 struct md_thread *thread; 548 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; 549 struct r5worker_group *worker_groups; 550 int group_cnt; 551 int worker_cnt_per_group; 552 struct r5l_log *log; 553 }; 554 555 556 /* 557 * Our supported algorithms 558 */ 559 #define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */ 560 #define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */ 561 #define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */ 562 #define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */ 563 564 /* Define non-rotating (raid4) algorithms. These allow 565 * conversion of raid4 to raid5. 566 */ 567 #define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */ 568 #define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */ 569 570 /* DDF RAID6 layouts differ from md/raid6 layouts in two ways. 571 * Firstly, the exact positioning of the parity block is slightly 572 * different between the 'LEFT_*' modes of md and the "_N_*" modes 573 * of DDF. 574 * Secondly, or order of datablocks over which the Q syndrome is computed 575 * is different. 576 * Consequently we have different layouts for DDF/raid6 than md/raid6. 577 * These layouts are from the DDFv1.2 spec. 578 * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but 579 * leaves RLQ=3 as 'Vendor Specific' 580 */ 581 582 #define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */ 583 #define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */ 584 #define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */ 585 586 /* For every RAID5 algorithm we define a RAID6 algorithm 587 * with exactly the same layout for data and parity, and 588 * with the Q block always on the last device (N-1). 589 * This allows trivial conversion from RAID5 to RAID6 590 */ 591 #define ALGORITHM_LEFT_ASYMMETRIC_6 16 592 #define ALGORITHM_RIGHT_ASYMMETRIC_6 17 593 #define ALGORITHM_LEFT_SYMMETRIC_6 18 594 #define ALGORITHM_RIGHT_SYMMETRIC_6 19 595 #define ALGORITHM_PARITY_0_6 20 596 #define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N 597 598 static inline int algorithm_valid_raid5(int layout) 599 { 600 return (layout >= 0) && 601 (layout <= 5); 602 } 603 static inline int algorithm_valid_raid6(int layout) 604 { 605 return (layout >= 0 && layout <= 5) 606 || 607 (layout >= 8 && layout <= 10) 608 || 609 (layout >= 16 && layout <= 20); 610 } 611 612 static inline int algorithm_is_DDF(int layout) 613 { 614 return layout >= 8 && layout <= 10; 615 } 616 617 extern void md_raid5_kick_device(struct r5conf *conf); 618 extern int raid5_set_cache_size(struct mddev *mddev, int size); 619 extern sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous); 620 extern void raid5_release_stripe(struct stripe_head *sh); 621 extern sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector, 622 int previous, int *dd_idx, 623 struct stripe_head *sh); 624 extern struct stripe_head * 625 raid5_get_active_stripe(struct r5conf *conf, sector_t sector, 626 int previous, int noblock, int noquiesce); 627 extern int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev); 628 extern void r5l_exit_log(struct r5l_log *log); 629 extern int r5l_write_stripe(struct r5l_log *log, struct stripe_head *head_sh); 630 extern void r5l_write_stripe_run(struct r5l_log *log); 631 extern void r5l_flush_stripe_to_raid(struct r5l_log *log); 632 extern void r5l_stripe_write_finished(struct stripe_head *sh); 633 extern int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio); 634 extern void r5l_quiesce(struct r5l_log *log, int state); 635 extern bool r5l_log_disk_error(struct r5conf *conf); 636 #endif 637