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