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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _RAID5_H3#define _RAID5_H4 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 in12 * one of a number of states stored in "flags". Changes between13 * these states happen *almost* exclusively under the protection of the14 * STRIPE_ACTIVE flag. Some very specific changes can happen in bi_end_io, and15 * 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_LOCKED19 *20 * State Empty == !UPTODATE, !LOCK21 * We have no data, and there is no active request22 * State Want == !UPTODATE, LOCK23 * A read request is being submitted for this block24 * State Dirty == UPTODATE, LOCK25 * Some new data is in this buffer, and it is being written out26 * State Clean == UPTODATE, !LOCK27 * We have valid data which is the same as on disc28 *29 * The possible state transitions are:30 *31 * Empty -> Want - on read or write to get old data for parity calc32 * Empty -> Dirty - on compute_parity to satisfy write/sync request.33 * Empty -> Clean - on compute_block when computing a block for failed drive34 * Want -> Empty - on failed read35 * Want -> Clean - on successful completion of read request36 * Dirty -> Clean - on successful completion of write request37 * Dirty -> Clean - on failed write38 * Clean -> Dirty - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW)39 *40 * The Want->Empty, Want->Clean, Dirty->Clean, transitions41 * 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->Clean45 * This is safe because thinking that a Clean buffer is actually dirty46 * will at worst delay some action, and the stripe will be scheduled47 * for attention after the transition is complete.48 *49 * There is one possibility that is not covered by these states. That50 * is if one drive has failed and there is a spare being rebuilt. We51 * can't distinguish between a clean block that has been generated52 * from parity calculations, and a clean block that has been53 * successfully written to the spare ( or to parity when resyncing).54 * To distinguish these states we have a stripe bit STRIPE_INSYNC that55 * is set whenever a write is scheduled to the spare, or to the parity56 * disc if there is no spare. A sync request clears this bit, and57 * when we find it set with no buffers locked, we know the sync is58 * complete.59 *60 * Buffers for the md device that arrive via make_request are attached61 * 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 lists64 * 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 is67 * Uptodate, the data is copied into the read buffer and it's b_end_io68 * routine is called. This may happen in the end_request routine only69 * if the buffer has just successfully been read. end_request should70 * remove the buffers from the list and then set the Uptodate bit on71 * the buffer. Other threads may do this only if they first check72 * that the Uptodate bit is set. Once they have checked that they may73 * take buffers off the read queue.74 *75 * When a buffer on the write list is committed for write it is copied76 * into the cache buffer, which is then marked dirty, and moved onto a77 * third list, the written list (bh_written). Once both the parity78 * block and the cached buffer are successfully written, any buffer on79 * 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 be84 * 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 on88 * neither). The "inactive_list" contains stripes which are not89 * currently being used for any request. They can freely be reused90 * for another stripe. The "handle_list" contains stripes that need91 * to be handled in some way. Both of these are fifo queues. Each92 * stripe is also (potentially) linked to a hash bucket in the hash93 * table so that it can be found by sector number. Stripes that are94 * not hashed must be on the inactive_list, and will normally be at95 * the front. All stripes start life this way.96 *97 * The inactive_list, handle_list and hash bucket lists are all protected by the98 * 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 on102 * handle_list else inactive_list103 *104 * This, combined with the fact that STRIPE_HANDLE is only ever105 * cleared while a stripe has a non-zero count means that if the106 * refcount is 0 and STRIPE_HANDLE is set, then it is on the107 * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then108 * 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 unlockdev113 * activate a hashed, possibly active stripe (get_active_stripe())114 * lockdev check-hash if(!cnt++)unlink-stripe unlockdev115 * attach a request to an active stripe (add_stripe_bh())116 * lockdev attach-buffer unlockdev117 * 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/ops122 * release an active stripe (release_stripe())123 * lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev124 *125 * The refcount counts each thread that have activated the stripe,126 * plus raid5d if it is handling it, plus one for each active request127 * on a cached buffer, and plus one if the stripe is undergoing stripe128 * operations.129 *130 * The stripe operations are:131 * -copying data between the stripe cache and user application buffers132 * -computing blocks to save a disk access, or to recover a missing block133 * -updating the parity on a write operation (reconstruct write and134 * read-modify-write)135 * -checking parity correctness136 * -running i/o to disk137 * These operations are carried out by raid5_run_ops which uses the async_tx138 * api to (optionally) offload operations to dedicated hardware engines.139 * When requesting an operation handle_stripe sets the pending bit for the140 * operation and increments the count. raid5_run_ops is then run whenever141 * the count is non-zero.142 * There are some critical dependencies between the operations that prevent some143 * 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_blocks146 * from starting while a check is in progress. Some dma engines can perform147 * the check without damaging the parity block, in these cases the parity148 * block is re-marked up to date (assuming the check was successful) and is149 * not re-read from disk.150 * 2/ When a write operation is requested we immediately lock the affected151 * blocks, and mark them as not up to date. This causes new read requests152 * 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 treats154 * that block as if it is up to date. raid5_run_ops guaruntees that any155 * operation that is dependent on the compute block result is initiated after156 * the compute block completes.157 */158 159/*160 * Operations state - intermediate states that are visible outside of161 * STRIPE_ACTIVE.162 * In general _idle indicates nothing is running, _run indicates a data163 * processing operation is active, and _result means the data processing result164 * is stable and can be acted upon. For simple operations like biofill and165 * compute that only have an _idle and _run state they are indicated with166 * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN)167 */168/**169 * enum check_states - handles syncing / repairing a stripe170 * @check_state_idle - check operations are quiesced171 * @check_state_run - check operation is running172 * @check_state_result - set outside lock when check result is valid173 * @check_state_compute_run - check failed and we are repairing174 * @check_state_compute_result - set outside lock when compute result is valid175 */176enum 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 stripe188 */189enum 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 4096200struct 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 every206 * 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 stripe218 * has STRIPE_BATCH_READY219 */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_operations242 * @target - STRIPE_OP_COMPUTE_BLK target243 * @target2 - 2nd compute target in the raid6 case244 * @zero_sum_result - P and Q verification flags245 * @request - async service request flags for raid_run_ops246 */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_SIZE253 /* 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#endif258 struct r5dev {259 /* rreq and rvec are used for the replacement device when260 * 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[]; /* allocated depending of RAID geometry ("disks" member) */272};273 274/* stripe_head_state - collects and tracks the dynamic state of a stripe_head275 * for handle_stripe.276 */277struct stripe_head_state {278 /* 'syncing' means that we need to read all devices, either279 * to check/correct parity, or to reconstruct a missing device.280 * 'replacing' means we are replacing one or more drives and281 * the source is valid at this point so we don't need to282 * 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 */300enum 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 request310 * 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 as317 * uptodate318 */319 R5_Wantfill, /* dev->toread contains a bio that needs320 * filling321 */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 been329 * fixed by writing to it */330 R5_NeedReplace, /* This device has a replacement which is not331 * up-to-date at this stripe. */332 R5_WantReplace, /* We need to update the replacement, we have read333 * 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 the339 * data and parity being written are in the journal340 * device341 */342 R5_OrigPageUPTDODATE, /* with write back cache, we read old data into343 * dev->orig_page for prexor. When this flag is344 * set, orig_page contains latest data in the345 * raid disk.346 */347};348 349/*350 * Stripe state351 */352enum {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 add376 * 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 phase382 * set in first entry of r5l_write_stripe383 * clear in second entry of r5l_write_stripe384 * used to bypass logic in handle_stripe385 *386 * 2. caching phase387 * set in r5c_try_caching_write()388 * clear when journal write is done389 * used to initiate r5c_cache_data()390 * also used to bypass logic in handle_stripe391 */392 STRIPE_R5C_CACHING, /* the stripe is in caching phase393 * see more detail in the raid5-cache.c394 */395 STRIPE_R5C_PARTIAL_STRIPE, /* in r5c cache (to-be/being handled or396 * in conf->r5c_partial_stripe_list)397 */398 STRIPE_R5C_FULL_STRIPE, /* in r5c cache (to-be/being handled or399 * 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 flags411 */412enum {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 preferences424 */425enum {426 PARITY_DISABLE_RMW = 0,427 PARITY_ENABLE_RMW,428 PARITY_PREFER_RMW,429};430 431/*432 * Pages requested from set_syndrome_sources()433 */434enum {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 some443 * stripes until there has been a chance that several write requests444 * for the one stripe have all been collected.445 * In particular, any write request that would require pre-reading446 * is put on a "delayed" queue until there are no stripes currently447 * in a pre-read phase. Further, if the "delayed" queue is empty when448 * a stripe is put on it then we "plug" the queue and do not process it449 * 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 add452 * it to the count of prereading stripes.453 * When write is initiated, or the stripe refcnt == 0 (just in case) we454 * clear the PREREAD_ACTIVE flag and decrement the count455 * Whenever the 'handle' queue is empty and the device is not plugged, we456 * move any strips from delayed to handle and clear the DELAYED flag and set457 * PREREAD_ACTIVE.458 * In stripe_handle, if we find pre-reading is necessary, we do it if459 * 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_mutex466 * 2/ when resync/recovery/reshape is known to be happening - i.e. in code that467 * is called as part of performing resync/recovery/reshape.468 * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer469 * and if it is non-NULL, increment rdev->nr_pending before dropping the RCU470 * lock.471 * When .rdev is set to NULL, the nr_pending count checked again and if472 * it has been incremented, the pointer is put back in .rdev.473 */474 475struct disk_info {476 struct md_rdev *rdev;477 struct md_rdev *replacement;478 struct page *extra_page; /* extra page to use in prexor */479};480 481/*482 * Stripe cache483 */484 485#define NR_STRIPES 256486 487#if PAGE_SIZE == DEFAULT_STRIPE_SIZE488#define STRIPE_SIZE PAGE_SIZE489#define STRIPE_SHIFT (PAGE_SHIFT - 9)490#define STRIPE_SECTORS (STRIPE_SIZE>>9)491#endif492 493#define IO_THRESHOLD 1494#define BYPASS_THRESHOLD 1495#define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))496#define HASH_MASK (NR_HASH - 1)497#define MAX_STRIPE_BATCH 8498 499/* NOTE NR_STRIPE_HASH_LOCKS must remain below 64.500 * This is because we sometimes take all the spinlocks501 * and creating that much locking depth can cause502 * problems.503 */504#define NR_STRIPE_HASH_LOCKS 8505#define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1)506 507struct r5worker {508 struct work_struct work;509 struct r5worker_group *group;510 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS];511 bool working;512};513 514struct r5worker_group {515 struct list_head handle_list;516 struct list_head loprio_list;517 struct r5conf *conf;518 struct r5worker *workers;519 int stripes_cnt;520};521 522/*523 * r5c journal modes of the array: write-back or write-through.524 * write-through mode has identical behavior as existing log only525 * implementation.526 */527enum r5c_journal_mode {528 R5C_JOURNAL_MODE_WRITE_THROUGH = 0,529 R5C_JOURNAL_MODE_WRITE_BACK = 1,530};531 532enum r5_cache_state {533 R5_INACTIVE_BLOCKED, /* release of inactive stripes blocked,534 * waiting for 25% to be free535 */536 R5_ALLOC_MORE, /* It might help to allocate another537 * stripe.538 */539 R5_DID_ALLOC, /* A stripe was allocated, don't allocate540 * more until at least one has been541 * released. This avoids flooding542 * the cache.543 */544 R5C_LOG_TIGHT, /* log device space tight, need to545 * prioritize stripes at last_checkpoint546 */547 R5C_LOG_CRITICAL, /* log device is running out of space,548 * only process stripes that are already549 * occupying the log550 */551 R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page552 * for prexor553 */554};555 556#define PENDING_IO_MAX 512557#define PENDING_IO_ONE_FLUSH 128558struct r5pending_data {559 struct list_head sibling;560 sector_t sector; /* stripe sector */561 struct bio_list bios;562};563 564struct raid5_percpu {565 struct page *spare_page; /* Used when checking P/Q in raid6 */566 void *scribble; /* space for constructing buffer567 * lists and performing address568 * conversions569 */570 int scribble_obj_size;571 local_lock_t lock;572};573 574struct r5conf {575 struct hlist_head *stripe_hashtbl;576 /* only protect corresponding hash list and inactive_list */577 spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS];578 struct mddev *mddev;579 int chunk_sectors;580 int level, algorithm, rmw_level;581 int max_degraded;582 int raid_disks;583 int max_nr_stripes;584 int min_nr_stripes;585#if PAGE_SIZE != DEFAULT_STRIPE_SIZE586 unsigned long stripe_size;587 unsigned int stripe_shift;588 unsigned long stripe_sectors;589#endif590 591 /* reshape_progress is the leading edge of a 'reshape'592 * It has value MaxSector when no reshape is happening593 * If delta_disks < 0, it is the last sector we started work on,594 * else is it the next sector to work on.595 */596 sector_t reshape_progress;597 /* reshape_safe is the trailing edge of a reshape. We know that598 * before (or after) this address, all reshape has completed.599 */600 sector_t reshape_safe;601 int previous_raid_disks;602 int prev_chunk_sectors;603 int prev_algo;604 short generation; /* increments with every reshape */605 seqcount_spinlock_t gen_lock; /* lock against generation changes */606 unsigned long reshape_checkpoint; /* Time we last updated607 * metadata */608 long long min_offset_diff; /* minimum difference between609 * data_offset and610 * new_data_offset across all611 * devices. May be negative,612 * but is closest to zero.613 */614 615 struct list_head handle_list; /* stripes needing handling */616 struct list_head loprio_list; /* low priority stripes */617 struct list_head hold_list; /* preread ready stripes */618 struct list_head delayed_list; /* stripes that have plugged requests */619 struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */620 struct bio *retry_read_aligned; /* currently retrying aligned bios */621 unsigned int retry_read_offset; /* sector offset into retry_read_aligned */622 struct bio *retry_read_aligned_list; /* aligned bios retry list */623 atomic_t preread_active_stripes; /* stripes with scheduled io */624 atomic_t active_aligned_reads;625 atomic_t pending_full_writes; /* full write backlog */626 int bypass_count; /* bypassed prereads */627 int bypass_threshold; /* preread nice */628 int skip_copy; /* Don't copy data from bio to stripe cache */629 struct list_head *last_hold; /* detect hold_list promotions */630 631 atomic_t reshape_stripes; /* stripes with pending writes for reshape */632 /* unfortunately we need two cache names as we temporarily have633 * two caches.634 */635 int active_name;636 char cache_name[2][32];637 struct kmem_cache *slab_cache; /* for allocating stripes */638 struct mutex cache_size_mutex; /* Protect changes to cache size */639 640 int seq_flush, seq_write;641 int quiesce;642 643 int fullsync; /* set to 1 if a full sync is needed,644 * (fresh device added).645 * Cleared when a sync completes.646 */647 int recovery_disabled;648 /* per cpu variables */649 struct raid5_percpu __percpu *percpu;650 int scribble_disks;651 int scribble_sectors;652 struct hlist_node node;653 654 /*655 * Free stripes pool656 */657 atomic_t active_stripes;658 struct list_head inactive_list[NR_STRIPE_HASH_LOCKS];659 660 atomic_t r5c_cached_full_stripes;661 struct list_head r5c_full_stripe_list;662 atomic_t r5c_cached_partial_stripes;663 struct list_head r5c_partial_stripe_list;664 atomic_t r5c_flushing_full_stripes;665 atomic_t r5c_flushing_partial_stripes;666 667 atomic_t empty_inactive_list_nr;668 struct llist_head released_stripes;669 wait_queue_head_t wait_for_quiescent;670 wait_queue_head_t wait_for_stripe;671 wait_queue_head_t wait_for_reshape;672 unsigned long cache_state;673 struct shrinker *shrinker;674 int pool_size; /* number of disks in stripeheads in pool */675 spinlock_t device_lock;676 struct disk_info *disks;677 struct bio_set bio_split;678 679 /* When taking over an array from a different personality, we store680 * the new thread here until we fully activate the array.681 */682 struct md_thread __rcu *thread;683 struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS];684 struct r5worker_group *worker_groups;685 int group_cnt;686 int worker_cnt_per_group;687 struct r5l_log *log;688 void *log_private;689 690 spinlock_t pending_bios_lock;691 bool batch_bio_dispatch;692 struct r5pending_data *pending_data;693 struct list_head free_list;694 struct list_head pending_list;695 int pending_data_cnt;696 struct r5pending_data *next_pending_data;697};698 699#if PAGE_SIZE == DEFAULT_STRIPE_SIZE700#define RAID5_STRIPE_SIZE(conf) STRIPE_SIZE701#define RAID5_STRIPE_SHIFT(conf) STRIPE_SHIFT702#define RAID5_STRIPE_SECTORS(conf) STRIPE_SECTORS703#else704#define RAID5_STRIPE_SIZE(conf) ((conf)->stripe_size)705#define RAID5_STRIPE_SHIFT(conf) ((conf)->stripe_shift)706#define RAID5_STRIPE_SECTORS(conf) ((conf)->stripe_sectors)707#endif708 709/* bio's attached to a stripe+device for I/O are linked together in bi_sector710 * order without overlap. There may be several bio's per stripe+device, and711 * a bio could span several devices.712 * When walking this list for a particular stripe+device, we must never proceed713 * beyond a bio that extends past this device, as the next bio might no longer714 * be valid.715 * This function is used to determine the 'next' bio in the list, given the716 * sector of the current stripe+device717 */718static inline struct bio *r5_next_bio(struct r5conf *conf, struct bio *bio, sector_t sector)719{720 if (bio_end_sector(bio) < sector + RAID5_STRIPE_SECTORS(conf))721 return bio->bi_next;722 else723 return NULL;724}725 726/*727 * Our supported algorithms728 */729#define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */730#define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */731#define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */732#define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */733 734/* Define non-rotating (raid4) algorithms. These allow735 * conversion of raid4 to raid5.736 */737#define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */738#define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */739 740/* DDF RAID6 layouts differ from md/raid6 layouts in two ways.741 * Firstly, the exact positioning of the parity block is slightly742 * different between the 'LEFT_*' modes of md and the "_N_*" modes743 * of DDF.744 * Secondly, or order of datablocks over which the Q syndrome is computed745 * is different.746 * Consequently we have different layouts for DDF/raid6 than md/raid6.747 * These layouts are from the DDFv1.2 spec.748 * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but749 * leaves RLQ=3 as 'Vendor Specific'750 */751 752#define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */753#define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */754#define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */755 756/* For every RAID5 algorithm we define a RAID6 algorithm757 * with exactly the same layout for data and parity, and758 * with the Q block always on the last device (N-1).759 * This allows trivial conversion from RAID5 to RAID6760 */761#define ALGORITHM_LEFT_ASYMMETRIC_6 16762#define ALGORITHM_RIGHT_ASYMMETRIC_6 17763#define ALGORITHM_LEFT_SYMMETRIC_6 18764#define ALGORITHM_RIGHT_SYMMETRIC_6 19765#define ALGORITHM_PARITY_0_6 20766#define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N767 768static inline int algorithm_valid_raid5(int layout)769{770 return (layout >= 0) &&771 (layout <= 5);772}773static inline int algorithm_valid_raid6(int layout)774{775 return (layout >= 0 && layout <= 5)776 ||777 (layout >= 8 && layout <= 10)778 ||779 (layout >= 16 && layout <= 20);780}781 782static inline int algorithm_is_DDF(int layout)783{784 return layout >= 8 && layout <= 10;785}786 787#if PAGE_SIZE != DEFAULT_STRIPE_SIZE788/*789 * Return offset of the corresponding page for r5dev.790 */791static inline int raid5_get_page_offset(struct stripe_head *sh, int disk_idx)792{793 return (disk_idx % sh->stripes_per_page) * RAID5_STRIPE_SIZE(sh->raid_conf);794}795 796/*797 * Return corresponding page address for r5dev.798 */799static inline struct page *800raid5_get_dev_page(struct stripe_head *sh, int disk_idx)801{802 return sh->pages[disk_idx / sh->stripes_per_page];803}804#endif805 806void md_raid5_kick_device(struct r5conf *conf);807int raid5_set_cache_size(struct mddev *mddev, int size);808sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous);809void raid5_release_stripe(struct stripe_head *sh);810sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,811 int previous, int *dd_idx, struct stripe_head *sh);812 813struct stripe_request_ctx;814/* get stripe from previous generation (when reshaping) */815#define R5_GAS_PREVIOUS (1 << 0)816/* do not block waiting for a free stripe */817#define R5_GAS_NOBLOCK (1 << 1)818/* do not block waiting for quiesce to be released */819#define R5_GAS_NOQUIESCE (1 << 2)820struct stripe_head *raid5_get_active_stripe(struct r5conf *conf,821 struct stripe_request_ctx *ctx, sector_t sector,822 unsigned int flags);823 824int raid5_calc_degraded(struct r5conf *conf);825int r5c_journal_mode_set(struct mddev *mddev, int journal_mode);826#endif827