/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _RAID5_H #define _RAID5_H #include <linux/raid/xor.h> #include <linux/dmaengine.h> #include <linux/local_lock.h> /* * * Each stripe contains one buffer per device. Each buffer can be in * one of a number of states stored in "flags". Changes between * these states happen *almost* exclusively under the protection of the * STRIPE_ACTIVE flag. Some very specific changes can happen in bi_end_io, and * these are not protected by STRIPE_ACTIVE. * * The flag bits that are used to represent these states are: * R5_UPTODATE and R5_LOCKED * * State Empty == !UPTODATE, !LOCK * We have no data, and there is no active request * State Want == !UPTODATE, LOCK * A read request is being submitted for this block * State Dirty == UPTODATE, LOCK * Some new data is in this buffer, and it is being written out * State Clean == UPTODATE, !LOCK * We have valid data which is the same as on disc * * The possible state transitions are: * * Empty -> Want - on read or write to get old data for parity calc * Empty -> Dirty - on compute_parity to satisfy write/sync request. * Empty -> Clean - on compute_block when computing a block for failed drive * Want -> Empty - on failed read * Want -> Clean - on successful completion of read request * Dirty -> Clean - on successful completion of write request * Dirty -> Clean - on failed write * Clean -> Dirty - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW) * * The Want->Empty, Want->Clean, Dirty->Clean, transitions * all happen in b_end_io at interrupt time. * Each sets the Uptodate bit before releasing the Lock bit. * This leaves one multi-stage transition: * Want->Dirty->Clean * This is safe because thinking that a Clean buffer is actually dirty * will at worst delay some action, and the stripe will be scheduled * for attention after the transition is complete. * * There is one possibility that is not covered by these states. That * is if one drive has failed and there is a spare being rebuilt. We * can't distinguish between a clean block that has been generated * from parity calculations, and a clean block that has been * successfully written to the spare ( or to parity when resyncing). * To distinguish these states we have a stripe bit STRIPE_INSYNC that * is set whenever a write is scheduled to the spare, or to the parity * disc if there is no spare. A sync request clears this bit, and * when we find it set with no buffers locked, we know the sync is * complete. * * Buffers for the md device that arrive via make_request are attached * to the appropriate stripe in one of two lists linked on b_reqnext. * One list (bh_read) for read requests, one (bh_write) for write. * There should never be more than one buffer on the two lists * together, but we are not guaranteed of that so we allow for more. * * If a buffer is on the read list when the associated cache buffer is * Uptodate, the data is copied into the read buffer and it's b_end_io * routine is called. This may happen in the end_request routine only * if the buffer has just successfully been read. end_request should * remove the buffers from the list and then set the Uptodate bit on * the buffer. Other threads may do this only if they first check * that the Uptodate bit is set. Once they have checked that they may * take buffers off the read queue. * * When a buffer on the write list is committed for write it is copied * into the cache buffer, which is then marked dirty, and moved onto a * third list, the written list (bh_written). Once both the parity * block and the cached buffer are successfully written, any buffer on * a written list can be returned with b_end_io. * * The write list and read list both act as fifos. The read list, * write list and written list are protected by the device_lock. * The device_lock is only for list manipulations and will only be * held for a very short time. It can be claimed from interrupts. * * * Stripes in the stripe cache can be on one of two lists (or on * neither). The "inactive_list" contains stripes which are not * currently being used for any request. They can freely be reused * for another stripe. The "handle_list" contains stripes that need * to be handled in some way. Both of these are fifo queues. Each * stripe is also (potentially) linked to a hash bucket in the hash * table so that it can be found by sector number. Stripes that are * not hashed must be on the inactive_list, and will normally be at * the front. All stripes start life this way. * * The inactive_list, handle_list and hash bucket lists are all protected by the * device_lock. * - stripes have a reference counter. If count==0, they are on a list. * - If a stripe might need handling, STRIPE_HANDLE is set. * - When refcount reaches zero, then if STRIPE_HANDLE it is put on * handle_list else inactive_list * * This, combined with the fact that STRIPE_HANDLE is only ever * cleared while a stripe has a non-zero count means that if the * refcount is 0 and STRIPE_HANDLE is set, then it is on the * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then * the stripe is on inactive_list. * * The possible transitions are: * activate an unhashed/inactive stripe (get_active_stripe()) * lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev * activate a hashed, possibly active stripe (get_active_stripe()) * lockdev check-hash if(!cnt++)unlink-stripe unlockdev * attach a request to an active stripe (add_stripe_bh()) * lockdev attach-buffer unlockdev * handle a stripe (handle_stripe()) * setSTRIPE_ACTIVE, clrSTRIPE_HANDLE ... * (lockdev check-buffers unlockdev) .. * change-state .. * record io/ops needed clearSTRIPE_ACTIVE schedule io/ops * release an active stripe (release_stripe()) * lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev * * The refcount counts each thread that have activated the stripe, * plus raid5d if it is handling it, plus one for each active request * on a cached buffer, and plus one if the stripe is undergoing stripe * operations. * * The stripe operations are: * -copying data between the stripe cache and user application buffers * -computing blocks to save a disk access, or to recover a missing block * -updating the parity on a write operation (reconstruct write and * read-modify-write) * -checking parity correctness * -running i/o to disk * These operations are carried out by raid5_run_ops which uses the async_tx * api to (optionally) offload operations to dedicated hardware engines. * When requesting an operation handle_stripe sets the pending bit for the * operation and increments the count. raid5_run_ops is then run whenever * the count is non-zero. * There are some critical dependencies between the operations that prevent some * from being requested while another is in flight. * 1/ Parity check operations destroy the in cache version of the parity block, * so we prevent parity dependent operations like writes and compute_blocks * from starting while a check is in progress. Some dma engines can perform * the check without damaging the parity block, in these cases the parity * block is re-marked up to date (assuming the check was successful) and is * not re-read from disk. * 2/ When a write operation is requested we immediately lock the affected * blocks, and mark them as not up to date. This causes new read requests * to be held off, as well as parity checks and compute block operations. * 3/ Once a compute block operation has been requested handle_stripe treats * that block as if it is up to date. raid5_run_ops guaruntees that any * operation that is dependent on the compute block result is initiated after * the compute block completes. */ /* * Operations state - intermediate states that are visible outside of * STRIPE_ACTIVE. * In general _idle indicates nothing is running, _run indicates a data * processing operation is active, and _result means the data processing result * is stable and can be acted upon. For simple operations like biofill and * compute that only have an _idle and _run state they are indicated with * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN) */ /** * enum check_states - handles syncing / repairing a stripe * @check_state_idle - check operations are quiesced * @check_state_run - check operation is running * @check_state_result - set outside lock when check result is valid * @check_state_compute_run - check failed and we are repairing * @check_state_compute_result - set outside lock when compute result is valid */ enum check_states { check_state_idle = 0, check_state_run, /* xor parity check */ check_state_run_q, /* q-parity check */ check_state_run_pq, /* pq dual parity check */ check_state_check_result, check_state_compute_run, /* parity repair */ check_state_compute_result, }; /** * enum reconstruct_states - handles writing or expanding a stripe */ enum reconstruct_states { reconstruct_state_idle = 0, reconstruct_state_prexor_drain_run, /* prexor-write */ reconstruct_state_drain_run, /* write */ reconstruct_state_run, /* expand */ reconstruct_state_prexor_drain_result, reconstruct_state_drain_result, reconstruct_state_result, }; #define DEFAULT_STRIPE_SIZE 4096 struct stripe_head { struct hlist_node hash; struct list_head lru; /* inactive_list or handle_list */ struct llist_node release_list; struct r5conf *raid_conf; short generation; /* increments with every * reshape */ sector_t sector; /* sector of this row */ short pd_idx; /* parity disk index */ short qd_idx; /* 'Q' disk index for raid6 */ short ddf_layout;/* use DDF ordering to calculate Q */ short hash_lock_index; unsigned long state; /* state flags */ atomic_t count; /* nr of active thread/requests */ int bm_seq; /* sequence number for bitmap flushes */ int disks; /* disks in stripe */ int overwrite_disks; /* total overwrite disks in stripe, * this is only checked when stripe * has STRIPE_BATCH_READY */ enum check_states check_state; enum reconstruct_states reconstruct_state; spinlock_t stripe_lock; int cpu; struct r5worker_group *group; struct stripe_head *batch_head; /* protected by stripe lock */ spinlock_t batch_lock; /* only header's lock is useful */ struct list_head batch_list; /* protected by head's batch lock*/ union { struct r5l_io_unit *log_io; struct ppl_io_unit *ppl_io; }; struct list_head log_list; sector_t log_start; /* first meta block on the journal */ struct list_head r5c; /* for r5c_cache->stripe_in_journal */ struct page *ppl_page; /* partial parity of this stripe */ /** * struct stripe_operations * @target - STRIPE_OP_COMPUTE_BLK target * @target2 - 2nd compute target in the raid6 case * @zero_sum_result - P and Q verification flags * @request - async service request flags for raid_run_ops */ struct stripe_operations { int target, target2; enum sum_check_flags zero_sum_result; } ops; #if PAGE_SIZE != DEFAULT_STRIPE_SIZE /* These pages will be used by bios in dev[i] */ struct page **pages; int nr_pages; /* page array size */ int stripes_per_page; #endif struct r5dev { /* rreq and rvec are used for the replacement device when * writing data to both devices. */ struct bio req, rreq; struct bio_vec vec, rvec; struct page *page, *orig_page; unsigned int offset; /* offset of the page */ struct bio *toread, *read, *towrite, *written; sector_t sector; /* sector of this page */ unsigned long flags; u32 log_checksum; unsigned short write_hint; } dev[]; /* allocated depending of RAID geometry ("disks" member) */ }; /* stripe_head_state - collects and tracks the dynamic state of a stripe_head * for handle_stripe. */ struct stripe_head_state { /* 'syncing' means that we need to read all devices, either * to check/correct parity, or to reconstruct a missing device. * 'replacing' means we are replacing one or more drives and * the source is valid at this point so we don't need to * read all devices, just the replacement targets. */ int syncing, expanding, expanded, replacing; int locked, uptodate, to_read, to_write, failed, written; int to_fill, compute, req_compute, non_overwrite; int injournal, just_cached; int failed_num[2]; int p_failed, q_failed; int dec_preread_active; unsigned long ops_request; struct md_rdev *blocked_rdev; int handle_bad_blocks; int log_failed; int waiting_extra_page; }; /* Flags for struct r5dev.flags */ enum r5dev_flags { R5_UPTODATE, /* page contains current data */ R5_LOCKED, /* IO has been submitted on "req" */ R5_DOUBLE_LOCKED,/* Cannot clear R5_LOCKED until 2 writes complete */ R5_OVERWRITE, /* towrite covers whole page */ /* and some that are internal to handle_stripe */ R5_Insync, /* rdev && rdev->in_sync at start */ R5_Wantread, /* want to schedule a read */ R5_Wantwrite, R5_Overlap, /* There is a pending overlapping request * on this block */ R5_ReadNoMerge, /* prevent bio from merging in block-layer */ R5_ReadError, /* seen a read error here recently */ R5_ReWrite, /* have tried to over-write the readerror */ R5_Expanded, /* This block now has post-expand data */ R5_Wantcompute, /* compute_block in progress treat as * uptodate */ R5_Wantfill, /* dev->toread contains a bio that needs * filling */ R5_Wantdrain, /* dev->towrite needs to be drained */ R5_WantFUA, /* Write should be FUA */ R5_SyncIO, /* The IO is sync */ R5_WriteError, /* got a write error - need to record it */ R5_MadeGood, /* A bad block has been fixed by writing to it */ R5_ReadRepl, /* Will/did read from replacement rather than orig */ R5_MadeGoodRepl,/* A bad block on the replacement device has been * fixed by writing to it */ R5_NeedReplace, /* This device has a replacement which is not * up-to-date at this stripe. */ R5_WantReplace, /* We need to update the replacement, we have read * data in, and now is a good time to write it out. */ R5_Discard, /* Discard the stripe */ R5_SkipCopy, /* Don't copy data from bio to stripe cache */ R5_InJournal, /* data being written is in the journal device. * if R5_InJournal is set for parity pd_idx, all the * data and parity being written are in the journal * device */ R5_OrigPageUPTDODATE, /* with write back cache, we read old data into * dev->orig_page for prexor. When this flag is * set, orig_page contains latest data in the * raid disk. */ }; /* * Stripe state */ enum { STRIPE_ACTIVE, STRIPE_HANDLE, STRIPE_SYNC_REQUESTED, STRIPE_SYNCING, STRIPE_INSYNC, STRIPE_REPLACED, STRIPE_PREREAD_ACTIVE, STRIPE_DELAYED, STRIPE_BIT_DELAY, STRIPE_EXPANDING, STRIPE_EXPAND_SOURCE, STRIPE_EXPAND_READY, STRIPE_IO_STARTED, /* do not count towards 'bypass_count' */ STRIPE_FULL_WRITE, /* all blocks are set to be overwritten */ STRIPE_BIOFILL_RUN, STRIPE_COMPUTE_RUN, STRIPE_ON_UNPLUG_LIST, STRIPE_DISCARD, STRIPE_ON_RELEASE_LIST, STRIPE_BATCH_READY, STRIPE_BATCH_ERR, STRIPE_LOG_TRAPPED, /* trapped into log (see raid5-cache.c) * this bit is used in two scenarios: * * 1. write-out phase * set in first entry of r5l_write_stripe * clear in second entry of r5l_write_stripe * used to bypass logic in handle_stripe * * 2. caching phase * set in r5c_try_caching_write() * clear when journal write is done * used to initiate r5c_cache_data() * also used to bypass logic in handle_stripe */ STRIPE_R5C_CACHING, /* the stripe is in caching phase * see more detail in the raid5-cache.c */ STRIPE_R5C_PARTIAL_STRIPE, /* in r5c cache (to-be/being handled or * in conf->r5c_partial_stripe_list) */ STRIPE_R5C_FULL_STRIPE, /* in r5c cache (to-be/being handled or * in conf->r5c_full_stripe_list) */ STRIPE_R5C_PREFLUSH, /* need to flush journal device */ }; #define STRIPE_EXPAND_SYNC_FLAGS \ ((1 << STRIPE_EXPAND_SOURCE) |\ (1 << STRIPE_EXPAND_READY) |\ (1 << STRIPE_EXPANDING) |\ (1 << STRIPE_SYNC_REQUESTED)) /* * Operation request flags */ enum { STRIPE_OP_BIOFILL, STRIPE_OP_COMPUTE_BLK, STRIPE_OP_PREXOR, STRIPE_OP_BIODRAIN, STRIPE_OP_RECONSTRUCT, STRIPE_OP_CHECK, STRIPE_OP_PARTIAL_PARITY, }; /* * RAID parity calculation preferences */ enum { PARITY_DISABLE_RMW = 0, PARITY_ENABLE_RMW, PARITY_PREFER_RMW, }; /* * Pages requested from set_syndrome_sources() */ enum { SYNDROME_SRC_ALL, SYNDROME_SRC_WANT_DRAIN, SYNDROME_SRC_WRITTEN, }; /* * Plugging: * * To improve write throughput, we need to delay the handling of some * stripes until there has been a chance that several write requests * for the one stripe have all been collected. * In particular, any write request that would require pre-reading * is put on a "delayed" queue until there are no stripes currently * in a pre-read phase. Further, if the "delayed" queue is empty when * a stripe is put on it then we "plug" the queue and do not process it * until an unplug call is made. (the unplug_io_fn() is called). * * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add * it to the count of prereading stripes. * When write is initiated, or the stripe refcnt == 0 (just in case) we * clear the PREREAD_ACTIVE flag and decrement the count * Whenever the 'handle' queue is empty and the device is not plugged, we * move any strips from delayed to handle and clear the DELAYED flag and set * PREREAD_ACTIVE. * In stripe_handle, if we find pre-reading is necessary, we do it if * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue. * HANDLE gets cleared if stripe_handle leaves nothing locked. */ /* Note: disk_info.rdev can be set to NULL asynchronously by raid5_remove_disk. * There are three safe ways to access disk_info.rdev. * 1/ when holding mddev->reconfig_mutex * 2/ when resync/recovery/reshape is known to be happening - i.e. in code that * is called as part of performing resync/recovery/reshape. * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer * and if it is non-NULL, increment rdev->nr_pending before dropping the RCU * lock. * When .rdev is set to NULL, the nr_pending count checked again and if * it has been incremented, the pointer is put back in .rdev. */ struct disk_info { struct md_rdev *rdev; struct md_rdev *replacement; struct page *extra_page; /* extra page to use in prexor */ }; /* * Stripe cache */ #define NR_STRIPES 256 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE #define STRIPE_SIZE PAGE_SIZE #define STRIPE_SHIFT (PAGE_SHIFT - 9) #define STRIPE_SECTORS (STRIPE_SIZE>>9) #endif #define IO_THRESHOLD 1 #define BYPASS_THRESHOLD 1 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) #define HASH_MASK (NR_HASH - 1) #define MAX_STRIPE_BATCH 8 /* NOTE NR_STRIPE_HASH_LOCKS must remain below 64. * This is because we sometimes take all the spinlocks * and creating that much locking depth can cause * problems. */ #define NR_STRIPE_HASH_LOCKS 8 #define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1) struct r5worker { struct work_struct work; struct r5worker_group *group; struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; bool working; }; struct r5worker_group { struct list_head handle_list; struct list_head loprio_list; struct r5conf *conf; struct r5worker *workers; int stripes_cnt; }; /* * r5c journal modes of the array: write-back or write-through. * write-through mode has identical behavior as existing log only * implementation. */ enum r5c_journal_mode { R5C_JOURNAL_MODE_WRITE_THROUGH = 0, R5C_JOURNAL_MODE_WRITE_BACK = 1, }; enum r5_cache_state { R5_INACTIVE_BLOCKED, /* release of inactive stripes blocked, * waiting for 25% to be free */ R5_ALLOC_MORE, /* It might help to allocate another * stripe. */ R5_DID_ALLOC, /* A stripe was allocated, don't allocate * more until at least one has been * released. This avoids flooding * the cache. */ R5C_LOG_TIGHT, /* log device space tight, need to * prioritize stripes at last_checkpoint */ R5C_LOG_CRITICAL, /* log device is running out of space, * only process stripes that are already * occupying the log */ R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page * for prexor */ }; #define PENDING_IO_MAX 512 #define PENDING_IO_ONE_FLUSH 128 struct r5pending_data { struct list_head sibling; sector_t sector; /* stripe sector */ struct bio_list bios; }; struct raid5_percpu { struct page *spare_page; /* Used when checking P/Q in raid6 */ void *scribble; /* space for constructing buffer * lists and performing address * conversions */ int scribble_obj_size; local_lock_t lock; }; struct r5conf { struct hlist_head *stripe_hashtbl; /* only protect corresponding hash list and inactive_list */ spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS]; struct mddev *mddev; int chunk_sectors; int level, algorithm, rmw_level; int max_degraded; int raid_disks; int max_nr_stripes; int min_nr_stripes; #if PAGE_SIZE != DEFAULT_STRIPE_SIZE unsigned long stripe_size; unsigned int stripe_shift; unsigned long stripe_sectors; #endif /* reshape_progress is the leading edge of a 'reshape' * It has value MaxSector when no reshape is happening * If delta_disks < 0, it is the last sector we started work on, * else is it the next sector to work on. */ sector_t reshape_progress; /* reshape_safe is the trailing edge of a reshape. We know that * before (or after) this address, all reshape has completed. */ sector_t reshape_safe; int previous_raid_disks; int prev_chunk_sectors; int prev_algo; short generation; /* increments with every reshape */ seqcount_spinlock_t gen_lock; /* lock against generation changes */ unsigned long reshape_checkpoint; /* Time we last updated * metadata */ long long min_offset_diff; /* minimum difference between * data_offset and * new_data_offset across all * devices. May be negative, * but is closest to zero. */ struct list_head handle_list; /* stripes needing handling */ struct list_head loprio_list; /* low priority stripes */ struct list_head hold_list; /* preread ready stripes */ struct list_head delayed_list; /* stripes that have plugged requests */ struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */ struct bio *retry_read_aligned; /* currently retrying aligned bios */ unsigned int retry_read_offset; /* sector offset into retry_read_aligned */ struct bio *retry_read_aligned_list; /* aligned bios retry list */ atomic_t preread_active_stripes; /* stripes with scheduled io */ atomic_t active_aligned_reads; atomic_t pending_full_writes; /* full write backlog */ int bypass_count; /* bypassed prereads */ int bypass_threshold; /* preread nice */ int skip_copy; /* Don't copy data from bio to stripe cache */ struct list_head *last_hold; /* detect hold_list promotions */ atomic_t reshape_stripes; /* stripes with pending writes for reshape */ /* unfortunately we need two cache names as we temporarily have * two caches. */ int active_name; char cache_name[2][48]; struct kmem_cache *slab_cache; /* for allocating stripes */ struct mutex cache_size_mutex; /* Protect changes to cache size */ int seq_flush, seq_write; int quiesce; int fullsync; /* set to 1 if a full sync is needed, * (fresh device added). * Cleared when a sync completes. */ /* per cpu variables */ struct raid5_percpu __percpu *percpu; int scribble_disks; int scribble_sectors; struct hlist_node node; /* * Free stripes pool */ atomic_t active_stripes; struct list_head inactive_list[NR_STRIPE_HASH_LOCKS]; atomic_t r5c_cached_full_stripes; struct list_head r5c_full_stripe_list; atomic_t r5c_cached_partial_stripes; struct list_head r5c_partial_stripe_list; atomic_t r5c_flushing_full_stripes; atomic_t r5c_flushing_partial_stripes; atomic_t empty_inactive_list_nr; struct llist_head released_stripes; wait_queue_head_t wait_for_quiescent; wait_queue_head_t wait_for_stripe; wait_queue_head_t wait_for_reshape; unsigned long cache_state; struct shrinker *shrinker; int pool_size; /* number of disks in stripeheads in pool */ spinlock_t device_lock; struct disk_info *disks; struct bio_set bio_split; /* When taking over an array from a different personality, we store * the new thread here until we fully activate the array. */ struct md_thread __rcu *thread; struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; struct r5worker_group *worker_groups; int group_cnt; int worker_cnt_per_group; struct r5l_log *log; void *log_private; spinlock_t pending_bios_lock; bool batch_bio_dispatch; struct r5pending_data *pending_data; struct list_head free_list; struct list_head pending_list; int pending_data_cnt; struct r5pending_data *next_pending_data; mempool_t *ctx_pool; int ctx_size; }; #if PAGE_SIZE == DEFAULT_STRIPE_SIZE #define RAID5_STRIPE_SIZE(conf) STRIPE_SIZE #define RAID5_STRIPE_SHIFT(conf) STRIPE_SHIFT #define RAID5_STRIPE_SECTORS(conf) STRIPE_SECTORS #else #define RAID5_STRIPE_SIZE(conf) ((conf)->stripe_size) #define RAID5_STRIPE_SHIFT(conf) ((conf)->stripe_shift) #define RAID5_STRIPE_SECTORS(conf) ((conf)->stripe_sectors) #endif /* bio's attached to a stripe+device for I/O are linked together in bi_sector * order without overlap. There may be several bio's per stripe+device, and * a bio could span several devices. * When walking this list for a particular stripe+device, we must never proceed * beyond a bio that extends past this device, as the next bio might no longer * be valid. * This function is used to determine the 'next' bio in the list, given the * sector of the current stripe+device */ static inline struct bio *r5_next_bio(struct r5conf *conf, struct bio *bio, sector_t sector) { if (bio_end_sector(bio) < sector + RAID5_STRIPE_SECTORS(conf)) return bio->bi_next; else return NULL; } /* * Our supported algorithms */ #define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */ #define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */ #define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */ #define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */ /* Define non-rotating (raid4) algorithms. These allow * conversion of raid4 to raid5. */ #define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */ #define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */ /* DDF RAID6 layouts differ from md/raid6 layouts in two ways. * Firstly, the exact positioning of the parity block is slightly * different between the 'LEFT_*' modes of md and the "_N_*" modes * of DDF. * Secondly, or order of datablocks over which the Q syndrome is computed * is different. * Consequently we have different layouts for DDF/raid6 than md/raid6. * These layouts are from the DDFv1.2 spec. * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but * leaves RLQ=3 as 'Vendor Specific' */ #define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */ #define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */ #define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */ /* For every RAID5 algorithm we define a RAID6 algorithm * with exactly the same layout for data and parity, and * with the Q block always on the last device (N-1). * This allows trivial conversion from RAID5 to RAID6 */ #define ALGORITHM_LEFT_ASYMMETRIC_6 16 #define ALGORITHM_RIGHT_ASYMMETRIC_6 17 #define ALGORITHM_LEFT_SYMMETRIC_6 18 #define ALGORITHM_RIGHT_SYMMETRIC_6 19 #define ALGORITHM_PARITY_0_6 20 #define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N static inline int algorithm_valid_raid5(int layout) { return (layout >= 0) && (layout <= 5); } static inline int algorithm_valid_raid6(int layout) { return (layout >= 0 && layout <= 5) || (layout >= 8 && layout <= 10) || (layout >= 16 && layout <= 20); } static inline int algorithm_is_DDF(int layout) { return layout >= 8 && layout <= 10; } #if PAGE_SIZE != DEFAULT_STRIPE_SIZE /* * Return offset of the corresponding page for r5dev. */ static inline int raid5_get_page_offset(struct stripe_head *sh, int disk_idx) { return (disk_idx % sh->stripes_per_page) * RAID5_STRIPE_SIZE(sh->raid_conf); } /* * Return corresponding page address for r5dev. */ static inline struct page * raid5_get_dev_page(struct stripe_head *sh, int disk_idx) { return sh->pages[disk_idx / sh->stripes_per_page]; } #endif void md_raid5_kick_device(struct r5conf *conf); int raid5_set_cache_size(struct mddev *mddev, int size); sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous); void raid5_release_stripe(struct stripe_head *sh); sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector, int previous, int *dd_idx, struct stripe_head *sh); struct stripe_request_ctx; /* get stripe from previous generation (when reshaping) */ #define R5_GAS_PREVIOUS (1 << 0) /* do not block waiting for a free stripe */ #define R5_GAS_NOBLOCK (1 << 1) /* do not block waiting for quiesce to be released */ #define R5_GAS_NOQUIESCE (1 << 2) struct stripe_head *raid5_get_active_stripe(struct r5conf *conf, struct stripe_request_ctx *ctx, sector_t sector, unsigned int flags); int raid5_calc_degraded(struct r5conf *conf); int r5c_journal_mode_set(struct mddev *mddev, int journal_mode); #endif
