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Merge tag 'char-misc-3.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregk...
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / md / raid5.c
1 /*
2 * raid5.c : Multiple Devices driver for Linux
3 * Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
4 * Copyright (C) 1999, 2000 Ingo Molnar
5 * Copyright (C) 2002, 2003 H. Peter Anvin
6 *
7 * RAID-4/5/6 management functions.
8 * Thanks to Penguin Computing for making the RAID-6 development possible
9 * by donating a test server!
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2, or (at your option)
14 * any later version.
15 *
16 * You should have received a copy of the GNU General Public License
17 * (for example /usr/src/linux/COPYING); if not, write to the Free
18 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21 /*
22 * BITMAP UNPLUGGING:
23 *
24 * The sequencing for updating the bitmap reliably is a little
25 * subtle (and I got it wrong the first time) so it deserves some
26 * explanation.
27 *
28 * We group bitmap updates into batches. Each batch has a number.
29 * We may write out several batches at once, but that isn't very important.
30 * conf->seq_write is the number of the last batch successfully written.
31 * conf->seq_flush is the number of the last batch that was closed to
32 * new additions.
33 * When we discover that we will need to write to any block in a stripe
34 * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
35 * the number of the batch it will be in. This is seq_flush+1.
36 * When we are ready to do a write, if that batch hasn't been written yet,
37 * we plug the array and queue the stripe for later.
38 * When an unplug happens, we increment bm_flush, thus closing the current
39 * batch.
40 * When we notice that bm_flush > bm_write, we write out all pending updates
41 * to the bitmap, and advance bm_write to where bm_flush was.
42 * This may occasionally write a bit out twice, but is sure never to
43 * miss any bits.
44 */
45
46 #include <linux/blkdev.h>
47 #include <linux/kthread.h>
48 #include <linux/raid/pq.h>
49 #include <linux/async_tx.h>
50 #include <linux/module.h>
51 #include <linux/async.h>
52 #include <linux/seq_file.h>
53 #include <linux/cpu.h>
54 #include <linux/slab.h>
55 #include <linux/ratelimit.h>
56 #include <trace/events/block.h>
57
58 #include "md.h"
59 #include "raid5.h"
60 #include "raid0.h"
61 #include "bitmap.h"
62
63 /*
64 * Stripe cache
65 */
66
67 #define NR_STRIPES 256
68 #define STRIPE_SIZE PAGE_SIZE
69 #define STRIPE_SHIFT (PAGE_SHIFT - 9)
70 #define STRIPE_SECTORS (STRIPE_SIZE>>9)
71 #define IO_THRESHOLD 1
72 #define BYPASS_THRESHOLD 1
73 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
74 #define HASH_MASK (NR_HASH - 1)
75
76 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
77 {
78 int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
79 return &conf->stripe_hashtbl[hash];
80 }
81
82 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
83 * order without overlap. There may be several bio's per stripe+device, and
84 * a bio could span several devices.
85 * When walking this list for a particular stripe+device, we must never proceed
86 * beyond a bio that extends past this device, as the next bio might no longer
87 * be valid.
88 * This function is used to determine the 'next' bio in the list, given the sector
89 * of the current stripe+device
90 */
91 static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
92 {
93 int sectors = bio_sectors(bio);
94 if (bio->bi_sector + sectors < sector + STRIPE_SECTORS)
95 return bio->bi_next;
96 else
97 return NULL;
98 }
99
100 /*
101 * We maintain a biased count of active stripes in the bottom 16 bits of
102 * bi_phys_segments, and a count of processed stripes in the upper 16 bits
103 */
104 static inline int raid5_bi_processed_stripes(struct bio *bio)
105 {
106 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
107 return (atomic_read(segments) >> 16) & 0xffff;
108 }
109
110 static inline int raid5_dec_bi_active_stripes(struct bio *bio)
111 {
112 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
113 return atomic_sub_return(1, segments) & 0xffff;
114 }
115
116 static inline void raid5_inc_bi_active_stripes(struct bio *bio)
117 {
118 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
119 atomic_inc(segments);
120 }
121
122 static inline void raid5_set_bi_processed_stripes(struct bio *bio,
123 unsigned int cnt)
124 {
125 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
126 int old, new;
127
128 do {
129 old = atomic_read(segments);
130 new = (old & 0xffff) | (cnt << 16);
131 } while (atomic_cmpxchg(segments, old, new) != old);
132 }
133
134 static inline void raid5_set_bi_stripes(struct bio *bio, unsigned int cnt)
135 {
136 atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
137 atomic_set(segments, cnt);
138 }
139
140 /* Find first data disk in a raid6 stripe */
141 static inline int raid6_d0(struct stripe_head *sh)
142 {
143 if (sh->ddf_layout)
144 /* ddf always start from first device */
145 return 0;
146 /* md starts just after Q block */
147 if (sh->qd_idx == sh->disks - 1)
148 return 0;
149 else
150 return sh->qd_idx + 1;
151 }
152 static inline int raid6_next_disk(int disk, int raid_disks)
153 {
154 disk++;
155 return (disk < raid_disks) ? disk : 0;
156 }
157
158 /* When walking through the disks in a raid5, starting at raid6_d0,
159 * We need to map each disk to a 'slot', where the data disks are slot
160 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
161 * is raid_disks-1. This help does that mapping.
162 */
163 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
164 int *count, int syndrome_disks)
165 {
166 int slot = *count;
167
168 if (sh->ddf_layout)
169 (*count)++;
170 if (idx == sh->pd_idx)
171 return syndrome_disks;
172 if (idx == sh->qd_idx)
173 return syndrome_disks + 1;
174 if (!sh->ddf_layout)
175 (*count)++;
176 return slot;
177 }
178
179 static void return_io(struct bio *return_bi)
180 {
181 struct bio *bi = return_bi;
182 while (bi) {
183
184 return_bi = bi->bi_next;
185 bi->bi_next = NULL;
186 bi->bi_size = 0;
187 trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
188 bi, 0);
189 bio_endio(bi, 0);
190 bi = return_bi;
191 }
192 }
193
194 static void print_raid5_conf (struct r5conf *conf);
195
196 static int stripe_operations_active(struct stripe_head *sh)
197 {
198 return sh->check_state || sh->reconstruct_state ||
199 test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
200 test_bit(STRIPE_COMPUTE_RUN, &sh->state);
201 }
202
203 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh)
204 {
205 BUG_ON(!list_empty(&sh->lru));
206 BUG_ON(atomic_read(&conf->active_stripes)==0);
207 if (test_bit(STRIPE_HANDLE, &sh->state)) {
208 if (test_bit(STRIPE_DELAYED, &sh->state) &&
209 !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
210 list_add_tail(&sh->lru, &conf->delayed_list);
211 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
212 sh->bm_seq - conf->seq_write > 0)
213 list_add_tail(&sh->lru, &conf->bitmap_list);
214 else {
215 clear_bit(STRIPE_DELAYED, &sh->state);
216 clear_bit(STRIPE_BIT_DELAY, &sh->state);
217 list_add_tail(&sh->lru, &conf->handle_list);
218 }
219 md_wakeup_thread(conf->mddev->thread);
220 } else {
221 BUG_ON(stripe_operations_active(sh));
222 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
223 if (atomic_dec_return(&conf->preread_active_stripes)
224 < IO_THRESHOLD)
225 md_wakeup_thread(conf->mddev->thread);
226 atomic_dec(&conf->active_stripes);
227 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
228 list_add_tail(&sh->lru, &conf->inactive_list);
229 wake_up(&conf->wait_for_stripe);
230 if (conf->retry_read_aligned)
231 md_wakeup_thread(conf->mddev->thread);
232 }
233 }
234 }
235
236 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh)
237 {
238 if (atomic_dec_and_test(&sh->count))
239 do_release_stripe(conf, sh);
240 }
241
242 static void release_stripe(struct stripe_head *sh)
243 {
244 struct r5conf *conf = sh->raid_conf;
245 unsigned long flags;
246
247 local_irq_save(flags);
248 if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
249 do_release_stripe(conf, sh);
250 spin_unlock(&conf->device_lock);
251 }
252 local_irq_restore(flags);
253 }
254
255 static inline void remove_hash(struct stripe_head *sh)
256 {
257 pr_debug("remove_hash(), stripe %llu\n",
258 (unsigned long long)sh->sector);
259
260 hlist_del_init(&sh->hash);
261 }
262
263 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
264 {
265 struct hlist_head *hp = stripe_hash(conf, sh->sector);
266
267 pr_debug("insert_hash(), stripe %llu\n",
268 (unsigned long long)sh->sector);
269
270 hlist_add_head(&sh->hash, hp);
271 }
272
273
274 /* find an idle stripe, make sure it is unhashed, and return it. */
275 static struct stripe_head *get_free_stripe(struct r5conf *conf)
276 {
277 struct stripe_head *sh = NULL;
278 struct list_head *first;
279
280 if (list_empty(&conf->inactive_list))
281 goto out;
282 first = conf->inactive_list.next;
283 sh = list_entry(first, struct stripe_head, lru);
284 list_del_init(first);
285 remove_hash(sh);
286 atomic_inc(&conf->active_stripes);
287 out:
288 return sh;
289 }
290
291 static void shrink_buffers(struct stripe_head *sh)
292 {
293 struct page *p;
294 int i;
295 int num = sh->raid_conf->pool_size;
296
297 for (i = 0; i < num ; i++) {
298 p = sh->dev[i].page;
299 if (!p)
300 continue;
301 sh->dev[i].page = NULL;
302 put_page(p);
303 }
304 }
305
306 static int grow_buffers(struct stripe_head *sh)
307 {
308 int i;
309 int num = sh->raid_conf->pool_size;
310
311 for (i = 0; i < num; i++) {
312 struct page *page;
313
314 if (!(page = alloc_page(GFP_KERNEL))) {
315 return 1;
316 }
317 sh->dev[i].page = page;
318 }
319 return 0;
320 }
321
322 static void raid5_build_block(struct stripe_head *sh, int i, int previous);
323 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
324 struct stripe_head *sh);
325
326 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
327 {
328 struct r5conf *conf = sh->raid_conf;
329 int i;
330
331 BUG_ON(atomic_read(&sh->count) != 0);
332 BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
333 BUG_ON(stripe_operations_active(sh));
334
335 pr_debug("init_stripe called, stripe %llu\n",
336 (unsigned long long)sh->sector);
337
338 remove_hash(sh);
339
340 sh->generation = conf->generation - previous;
341 sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
342 sh->sector = sector;
343 stripe_set_idx(sector, conf, previous, sh);
344 sh->state = 0;
345
346
347 for (i = sh->disks; i--; ) {
348 struct r5dev *dev = &sh->dev[i];
349
350 if (dev->toread || dev->read || dev->towrite || dev->written ||
351 test_bit(R5_LOCKED, &dev->flags)) {
352 printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n",
353 (unsigned long long)sh->sector, i, dev->toread,
354 dev->read, dev->towrite, dev->written,
355 test_bit(R5_LOCKED, &dev->flags));
356 WARN_ON(1);
357 }
358 dev->flags = 0;
359 raid5_build_block(sh, i, previous);
360 }
361 insert_hash(conf, sh);
362 }
363
364 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
365 short generation)
366 {
367 struct stripe_head *sh;
368
369 pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
370 hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
371 if (sh->sector == sector && sh->generation == generation)
372 return sh;
373 pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
374 return NULL;
375 }
376
377 /*
378 * Need to check if array has failed when deciding whether to:
379 * - start an array
380 * - remove non-faulty devices
381 * - add a spare
382 * - allow a reshape
383 * This determination is simple when no reshape is happening.
384 * However if there is a reshape, we need to carefully check
385 * both the before and after sections.
386 * This is because some failed devices may only affect one
387 * of the two sections, and some non-in_sync devices may
388 * be insync in the section most affected by failed devices.
389 */
390 static int calc_degraded(struct r5conf *conf)
391 {
392 int degraded, degraded2;
393 int i;
394
395 rcu_read_lock();
396 degraded = 0;
397 for (i = 0; i < conf->previous_raid_disks; i++) {
398 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
399 if (rdev && test_bit(Faulty, &rdev->flags))
400 rdev = rcu_dereference(conf->disks[i].replacement);
401 if (!rdev || test_bit(Faulty, &rdev->flags))
402 degraded++;
403 else if (test_bit(In_sync, &rdev->flags))
404 ;
405 else
406 /* not in-sync or faulty.
407 * If the reshape increases the number of devices,
408 * this is being recovered by the reshape, so
409 * this 'previous' section is not in_sync.
410 * If the number of devices is being reduced however,
411 * the device can only be part of the array if
412 * we are reverting a reshape, so this section will
413 * be in-sync.
414 */
415 if (conf->raid_disks >= conf->previous_raid_disks)
416 degraded++;
417 }
418 rcu_read_unlock();
419 if (conf->raid_disks == conf->previous_raid_disks)
420 return degraded;
421 rcu_read_lock();
422 degraded2 = 0;
423 for (i = 0; i < conf->raid_disks; i++) {
424 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
425 if (rdev && test_bit(Faulty, &rdev->flags))
426 rdev = rcu_dereference(conf->disks[i].replacement);
427 if (!rdev || test_bit(Faulty, &rdev->flags))
428 degraded2++;
429 else if (test_bit(In_sync, &rdev->flags))
430 ;
431 else
432 /* not in-sync or faulty.
433 * If reshape increases the number of devices, this
434 * section has already been recovered, else it
435 * almost certainly hasn't.
436 */
437 if (conf->raid_disks <= conf->previous_raid_disks)
438 degraded2++;
439 }
440 rcu_read_unlock();
441 if (degraded2 > degraded)
442 return degraded2;
443 return degraded;
444 }
445
446 static int has_failed(struct r5conf *conf)
447 {
448 int degraded;
449
450 if (conf->mddev->reshape_position == MaxSector)
451 return conf->mddev->degraded > conf->max_degraded;
452
453 degraded = calc_degraded(conf);
454 if (degraded > conf->max_degraded)
455 return 1;
456 return 0;
457 }
458
459 static struct stripe_head *
460 get_active_stripe(struct r5conf *conf, sector_t sector,
461 int previous, int noblock, int noquiesce)
462 {
463 struct stripe_head *sh;
464
465 pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
466
467 spin_lock_irq(&conf->device_lock);
468
469 do {
470 wait_event_lock_irq(conf->wait_for_stripe,
471 conf->quiesce == 0 || noquiesce,
472 conf->device_lock);
473 sh = __find_stripe(conf, sector, conf->generation - previous);
474 if (!sh) {
475 if (!conf->inactive_blocked)
476 sh = get_free_stripe(conf);
477 if (noblock && sh == NULL)
478 break;
479 if (!sh) {
480 conf->inactive_blocked = 1;
481 wait_event_lock_irq(conf->wait_for_stripe,
482 !list_empty(&conf->inactive_list) &&
483 (atomic_read(&conf->active_stripes)
484 < (conf->max_nr_stripes *3/4)
485 || !conf->inactive_blocked),
486 conf->device_lock);
487 conf->inactive_blocked = 0;
488 } else
489 init_stripe(sh, sector, previous);
490 } else {
491 if (atomic_read(&sh->count)) {
492 BUG_ON(!list_empty(&sh->lru)
493 && !test_bit(STRIPE_EXPANDING, &sh->state)
494 && !test_bit(STRIPE_ON_UNPLUG_LIST, &sh->state));
495 } else {
496 if (!test_bit(STRIPE_HANDLE, &sh->state))
497 atomic_inc(&conf->active_stripes);
498 if (list_empty(&sh->lru) &&
499 !test_bit(STRIPE_EXPANDING, &sh->state))
500 BUG();
501 list_del_init(&sh->lru);
502 }
503 }
504 } while (sh == NULL);
505
506 if (sh)
507 atomic_inc(&sh->count);
508
509 spin_unlock_irq(&conf->device_lock);
510 return sh;
511 }
512
513 /* Determine if 'data_offset' or 'new_data_offset' should be used
514 * in this stripe_head.
515 */
516 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
517 {
518 sector_t progress = conf->reshape_progress;
519 /* Need a memory barrier to make sure we see the value
520 * of conf->generation, or ->data_offset that was set before
521 * reshape_progress was updated.
522 */
523 smp_rmb();
524 if (progress == MaxSector)
525 return 0;
526 if (sh->generation == conf->generation - 1)
527 return 0;
528 /* We are in a reshape, and this is a new-generation stripe,
529 * so use new_data_offset.
530 */
531 return 1;
532 }
533
534 static void
535 raid5_end_read_request(struct bio *bi, int error);
536 static void
537 raid5_end_write_request(struct bio *bi, int error);
538
539 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
540 {
541 struct r5conf *conf = sh->raid_conf;
542 int i, disks = sh->disks;
543
544 might_sleep();
545
546 for (i = disks; i--; ) {
547 int rw;
548 int replace_only = 0;
549 struct bio *bi, *rbi;
550 struct md_rdev *rdev, *rrdev = NULL;
551 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
552 if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
553 rw = WRITE_FUA;
554 else
555 rw = WRITE;
556 if (test_bit(R5_Discard, &sh->dev[i].flags))
557 rw |= REQ_DISCARD;
558 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
559 rw = READ;
560 else if (test_and_clear_bit(R5_WantReplace,
561 &sh->dev[i].flags)) {
562 rw = WRITE;
563 replace_only = 1;
564 } else
565 continue;
566 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
567 rw |= REQ_SYNC;
568
569 bi = &sh->dev[i].req;
570 rbi = &sh->dev[i].rreq; /* For writing to replacement */
571
572 rcu_read_lock();
573 rrdev = rcu_dereference(conf->disks[i].replacement);
574 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
575 rdev = rcu_dereference(conf->disks[i].rdev);
576 if (!rdev) {
577 rdev = rrdev;
578 rrdev = NULL;
579 }
580 if (rw & WRITE) {
581 if (replace_only)
582 rdev = NULL;
583 if (rdev == rrdev)
584 /* We raced and saw duplicates */
585 rrdev = NULL;
586 } else {
587 if (test_bit(R5_ReadRepl, &sh->dev[i].flags) && rrdev)
588 rdev = rrdev;
589 rrdev = NULL;
590 }
591
592 if (rdev && test_bit(Faulty, &rdev->flags))
593 rdev = NULL;
594 if (rdev)
595 atomic_inc(&rdev->nr_pending);
596 if (rrdev && test_bit(Faulty, &rrdev->flags))
597 rrdev = NULL;
598 if (rrdev)
599 atomic_inc(&rrdev->nr_pending);
600 rcu_read_unlock();
601
602 /* We have already checked bad blocks for reads. Now
603 * need to check for writes. We never accept write errors
604 * on the replacement, so we don't to check rrdev.
605 */
606 while ((rw & WRITE) && rdev &&
607 test_bit(WriteErrorSeen, &rdev->flags)) {
608 sector_t first_bad;
609 int bad_sectors;
610 int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
611 &first_bad, &bad_sectors);
612 if (!bad)
613 break;
614
615 if (bad < 0) {
616 set_bit(BlockedBadBlocks, &rdev->flags);
617 if (!conf->mddev->external &&
618 conf->mddev->flags) {
619 /* It is very unlikely, but we might
620 * still need to write out the
621 * bad block log - better give it
622 * a chance*/
623 md_check_recovery(conf->mddev);
624 }
625 /*
626 * Because md_wait_for_blocked_rdev
627 * will dec nr_pending, we must
628 * increment it first.
629 */
630 atomic_inc(&rdev->nr_pending);
631 md_wait_for_blocked_rdev(rdev, conf->mddev);
632 } else {
633 /* Acknowledged bad block - skip the write */
634 rdev_dec_pending(rdev, conf->mddev);
635 rdev = NULL;
636 }
637 }
638
639 if (rdev) {
640 if (s->syncing || s->expanding || s->expanded
641 || s->replacing)
642 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
643
644 set_bit(STRIPE_IO_STARTED, &sh->state);
645
646 bio_reset(bi);
647 bi->bi_bdev = rdev->bdev;
648 bi->bi_rw = rw;
649 bi->bi_end_io = (rw & WRITE)
650 ? raid5_end_write_request
651 : raid5_end_read_request;
652 bi->bi_private = sh;
653
654 pr_debug("%s: for %llu schedule op %ld on disc %d\n",
655 __func__, (unsigned long long)sh->sector,
656 bi->bi_rw, i);
657 atomic_inc(&sh->count);
658 if (use_new_offset(conf, sh))
659 bi->bi_sector = (sh->sector
660 + rdev->new_data_offset);
661 else
662 bi->bi_sector = (sh->sector
663 + rdev->data_offset);
664 if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
665 bi->bi_rw |= REQ_FLUSH;
666
667 bi->bi_vcnt = 1;
668 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
669 bi->bi_io_vec[0].bv_offset = 0;
670 bi->bi_size = STRIPE_SIZE;
671 if (rrdev)
672 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
673
674 if (conf->mddev->gendisk)
675 trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
676 bi, disk_devt(conf->mddev->gendisk),
677 sh->dev[i].sector);
678 generic_make_request(bi);
679 }
680 if (rrdev) {
681 if (s->syncing || s->expanding || s->expanded
682 || s->replacing)
683 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
684
685 set_bit(STRIPE_IO_STARTED, &sh->state);
686
687 bio_reset(rbi);
688 rbi->bi_bdev = rrdev->bdev;
689 rbi->bi_rw = rw;
690 BUG_ON(!(rw & WRITE));
691 rbi->bi_end_io = raid5_end_write_request;
692 rbi->bi_private = sh;
693
694 pr_debug("%s: for %llu schedule op %ld on "
695 "replacement disc %d\n",
696 __func__, (unsigned long long)sh->sector,
697 rbi->bi_rw, i);
698 atomic_inc(&sh->count);
699 if (use_new_offset(conf, sh))
700 rbi->bi_sector = (sh->sector
701 + rrdev->new_data_offset);
702 else
703 rbi->bi_sector = (sh->sector
704 + rrdev->data_offset);
705 rbi->bi_vcnt = 1;
706 rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
707 rbi->bi_io_vec[0].bv_offset = 0;
708 rbi->bi_size = STRIPE_SIZE;
709 if (conf->mddev->gendisk)
710 trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
711 rbi, disk_devt(conf->mddev->gendisk),
712 sh->dev[i].sector);
713 generic_make_request(rbi);
714 }
715 if (!rdev && !rrdev) {
716 if (rw & WRITE)
717 set_bit(STRIPE_DEGRADED, &sh->state);
718 pr_debug("skip op %ld on disc %d for sector %llu\n",
719 bi->bi_rw, i, (unsigned long long)sh->sector);
720 clear_bit(R5_LOCKED, &sh->dev[i].flags);
721 set_bit(STRIPE_HANDLE, &sh->state);
722 }
723 }
724 }
725
726 static struct dma_async_tx_descriptor *
727 async_copy_data(int frombio, struct bio *bio, struct page *page,
728 sector_t sector, struct dma_async_tx_descriptor *tx)
729 {
730 struct bio_vec *bvl;
731 struct page *bio_page;
732 int i;
733 int page_offset;
734 struct async_submit_ctl submit;
735 enum async_tx_flags flags = 0;
736
737 if (bio->bi_sector >= sector)
738 page_offset = (signed)(bio->bi_sector - sector) * 512;
739 else
740 page_offset = (signed)(sector - bio->bi_sector) * -512;
741
742 if (frombio)
743 flags |= ASYNC_TX_FENCE;
744 init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
745
746 bio_for_each_segment(bvl, bio, i) {
747 int len = bvl->bv_len;
748 int clen;
749 int b_offset = 0;
750
751 if (page_offset < 0) {
752 b_offset = -page_offset;
753 page_offset += b_offset;
754 len -= b_offset;
755 }
756
757 if (len > 0 && page_offset + len > STRIPE_SIZE)
758 clen = STRIPE_SIZE - page_offset;
759 else
760 clen = len;
761
762 if (clen > 0) {
763 b_offset += bvl->bv_offset;
764 bio_page = bvl->bv_page;
765 if (frombio)
766 tx = async_memcpy(page, bio_page, page_offset,
767 b_offset, clen, &submit);
768 else
769 tx = async_memcpy(bio_page, page, b_offset,
770 page_offset, clen, &submit);
771 }
772 /* chain the operations */
773 submit.depend_tx = tx;
774
775 if (clen < len) /* hit end of page */
776 break;
777 page_offset += len;
778 }
779
780 return tx;
781 }
782
783 static void ops_complete_biofill(void *stripe_head_ref)
784 {
785 struct stripe_head *sh = stripe_head_ref;
786 struct bio *return_bi = NULL;
787 int i;
788
789 pr_debug("%s: stripe %llu\n", __func__,
790 (unsigned long long)sh->sector);
791
792 /* clear completed biofills */
793 for (i = sh->disks; i--; ) {
794 struct r5dev *dev = &sh->dev[i];
795
796 /* acknowledge completion of a biofill operation */
797 /* and check if we need to reply to a read request,
798 * new R5_Wantfill requests are held off until
799 * !STRIPE_BIOFILL_RUN
800 */
801 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
802 struct bio *rbi, *rbi2;
803
804 BUG_ON(!dev->read);
805 rbi = dev->read;
806 dev->read = NULL;
807 while (rbi && rbi->bi_sector <
808 dev->sector + STRIPE_SECTORS) {
809 rbi2 = r5_next_bio(rbi, dev->sector);
810 if (!raid5_dec_bi_active_stripes(rbi)) {
811 rbi->bi_next = return_bi;
812 return_bi = rbi;
813 }
814 rbi = rbi2;
815 }
816 }
817 }
818 clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
819
820 return_io(return_bi);
821
822 set_bit(STRIPE_HANDLE, &sh->state);
823 release_stripe(sh);
824 }
825
826 static void ops_run_biofill(struct stripe_head *sh)
827 {
828 struct dma_async_tx_descriptor *tx = NULL;
829 struct async_submit_ctl submit;
830 int i;
831
832 pr_debug("%s: stripe %llu\n", __func__,
833 (unsigned long long)sh->sector);
834
835 for (i = sh->disks; i--; ) {
836 struct r5dev *dev = &sh->dev[i];
837 if (test_bit(R5_Wantfill, &dev->flags)) {
838 struct bio *rbi;
839 spin_lock_irq(&sh->stripe_lock);
840 dev->read = rbi = dev->toread;
841 dev->toread = NULL;
842 spin_unlock_irq(&sh->stripe_lock);
843 while (rbi && rbi->bi_sector <
844 dev->sector + STRIPE_SECTORS) {
845 tx = async_copy_data(0, rbi, dev->page,
846 dev->sector, tx);
847 rbi = r5_next_bio(rbi, dev->sector);
848 }
849 }
850 }
851
852 atomic_inc(&sh->count);
853 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
854 async_trigger_callback(&submit);
855 }
856
857 static void mark_target_uptodate(struct stripe_head *sh, int target)
858 {
859 struct r5dev *tgt;
860
861 if (target < 0)
862 return;
863
864 tgt = &sh->dev[target];
865 set_bit(R5_UPTODATE, &tgt->flags);
866 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
867 clear_bit(R5_Wantcompute, &tgt->flags);
868 }
869
870 static void ops_complete_compute(void *stripe_head_ref)
871 {
872 struct stripe_head *sh = stripe_head_ref;
873
874 pr_debug("%s: stripe %llu\n", __func__,
875 (unsigned long long)sh->sector);
876
877 /* mark the computed target(s) as uptodate */
878 mark_target_uptodate(sh, sh->ops.target);
879 mark_target_uptodate(sh, sh->ops.target2);
880
881 clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
882 if (sh->check_state == check_state_compute_run)
883 sh->check_state = check_state_compute_result;
884 set_bit(STRIPE_HANDLE, &sh->state);
885 release_stripe(sh);
886 }
887
888 /* return a pointer to the address conversion region of the scribble buffer */
889 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
890 struct raid5_percpu *percpu)
891 {
892 return percpu->scribble + sizeof(struct page *) * (sh->disks + 2);
893 }
894
895 static struct dma_async_tx_descriptor *
896 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
897 {
898 int disks = sh->disks;
899 struct page **xor_srcs = percpu->scribble;
900 int target = sh->ops.target;
901 struct r5dev *tgt = &sh->dev[target];
902 struct page *xor_dest = tgt->page;
903 int count = 0;
904 struct dma_async_tx_descriptor *tx;
905 struct async_submit_ctl submit;
906 int i;
907
908 pr_debug("%s: stripe %llu block: %d\n",
909 __func__, (unsigned long long)sh->sector, target);
910 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
911
912 for (i = disks; i--; )
913 if (i != target)
914 xor_srcs[count++] = sh->dev[i].page;
915
916 atomic_inc(&sh->count);
917
918 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
919 ops_complete_compute, sh, to_addr_conv(sh, percpu));
920 if (unlikely(count == 1))
921 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
922 else
923 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
924
925 return tx;
926 }
927
928 /* set_syndrome_sources - populate source buffers for gen_syndrome
929 * @srcs - (struct page *) array of size sh->disks
930 * @sh - stripe_head to parse
931 *
932 * Populates srcs in proper layout order for the stripe and returns the
933 * 'count' of sources to be used in a call to async_gen_syndrome. The P
934 * destination buffer is recorded in srcs[count] and the Q destination
935 * is recorded in srcs[count+1]].
936 */
937 static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
938 {
939 int disks = sh->disks;
940 int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
941 int d0_idx = raid6_d0(sh);
942 int count;
943 int i;
944
945 for (i = 0; i < disks; i++)
946 srcs[i] = NULL;
947
948 count = 0;
949 i = d0_idx;
950 do {
951 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
952
953 srcs[slot] = sh->dev[i].page;
954 i = raid6_next_disk(i, disks);
955 } while (i != d0_idx);
956
957 return syndrome_disks;
958 }
959
960 static struct dma_async_tx_descriptor *
961 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
962 {
963 int disks = sh->disks;
964 struct page **blocks = percpu->scribble;
965 int target;
966 int qd_idx = sh->qd_idx;
967 struct dma_async_tx_descriptor *tx;
968 struct async_submit_ctl submit;
969 struct r5dev *tgt;
970 struct page *dest;
971 int i;
972 int count;
973
974 if (sh->ops.target < 0)
975 target = sh->ops.target2;
976 else if (sh->ops.target2 < 0)
977 target = sh->ops.target;
978 else
979 /* we should only have one valid target */
980 BUG();
981 BUG_ON(target < 0);
982 pr_debug("%s: stripe %llu block: %d\n",
983 __func__, (unsigned long long)sh->sector, target);
984
985 tgt = &sh->dev[target];
986 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
987 dest = tgt->page;
988
989 atomic_inc(&sh->count);
990
991 if (target == qd_idx) {
992 count = set_syndrome_sources(blocks, sh);
993 blocks[count] = NULL; /* regenerating p is not necessary */
994 BUG_ON(blocks[count+1] != dest); /* q should already be set */
995 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
996 ops_complete_compute, sh,
997 to_addr_conv(sh, percpu));
998 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
999 } else {
1000 /* Compute any data- or p-drive using XOR */
1001 count = 0;
1002 for (i = disks; i-- ; ) {
1003 if (i == target || i == qd_idx)
1004 continue;
1005 blocks[count++] = sh->dev[i].page;
1006 }
1007
1008 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1009 NULL, ops_complete_compute, sh,
1010 to_addr_conv(sh, percpu));
1011 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1012 }
1013
1014 return tx;
1015 }
1016
1017 static struct dma_async_tx_descriptor *
1018 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1019 {
1020 int i, count, disks = sh->disks;
1021 int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1022 int d0_idx = raid6_d0(sh);
1023 int faila = -1, failb = -1;
1024 int target = sh->ops.target;
1025 int target2 = sh->ops.target2;
1026 struct r5dev *tgt = &sh->dev[target];
1027 struct r5dev *tgt2 = &sh->dev[target2];
1028 struct dma_async_tx_descriptor *tx;
1029 struct page **blocks = percpu->scribble;
1030 struct async_submit_ctl submit;
1031
1032 pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1033 __func__, (unsigned long long)sh->sector, target, target2);
1034 BUG_ON(target < 0 || target2 < 0);
1035 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1036 BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1037
1038 /* we need to open-code set_syndrome_sources to handle the
1039 * slot number conversion for 'faila' and 'failb'
1040 */
1041 for (i = 0; i < disks ; i++)
1042 blocks[i] = NULL;
1043 count = 0;
1044 i = d0_idx;
1045 do {
1046 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1047
1048 blocks[slot] = sh->dev[i].page;
1049
1050 if (i == target)
1051 faila = slot;
1052 if (i == target2)
1053 failb = slot;
1054 i = raid6_next_disk(i, disks);
1055 } while (i != d0_idx);
1056
1057 BUG_ON(faila == failb);
1058 if (failb < faila)
1059 swap(faila, failb);
1060 pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1061 __func__, (unsigned long long)sh->sector, faila, failb);
1062
1063 atomic_inc(&sh->count);
1064
1065 if (failb == syndrome_disks+1) {
1066 /* Q disk is one of the missing disks */
1067 if (faila == syndrome_disks) {
1068 /* Missing P+Q, just recompute */
1069 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1070 ops_complete_compute, sh,
1071 to_addr_conv(sh, percpu));
1072 return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1073 STRIPE_SIZE, &submit);
1074 } else {
1075 struct page *dest;
1076 int data_target;
1077 int qd_idx = sh->qd_idx;
1078
1079 /* Missing D+Q: recompute D from P, then recompute Q */
1080 if (target == qd_idx)
1081 data_target = target2;
1082 else
1083 data_target = target;
1084
1085 count = 0;
1086 for (i = disks; i-- ; ) {
1087 if (i == data_target || i == qd_idx)
1088 continue;
1089 blocks[count++] = sh->dev[i].page;
1090 }
1091 dest = sh->dev[data_target].page;
1092 init_async_submit(&submit,
1093 ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1094 NULL, NULL, NULL,
1095 to_addr_conv(sh, percpu));
1096 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1097 &submit);
1098
1099 count = set_syndrome_sources(blocks, sh);
1100 init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1101 ops_complete_compute, sh,
1102 to_addr_conv(sh, percpu));
1103 return async_gen_syndrome(blocks, 0, count+2,
1104 STRIPE_SIZE, &submit);
1105 }
1106 } else {
1107 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1108 ops_complete_compute, sh,
1109 to_addr_conv(sh, percpu));
1110 if (failb == syndrome_disks) {
1111 /* We're missing D+P. */
1112 return async_raid6_datap_recov(syndrome_disks+2,
1113 STRIPE_SIZE, faila,
1114 blocks, &submit);
1115 } else {
1116 /* We're missing D+D. */
1117 return async_raid6_2data_recov(syndrome_disks+2,
1118 STRIPE_SIZE, faila, failb,
1119 blocks, &submit);
1120 }
1121 }
1122 }
1123
1124
1125 static void ops_complete_prexor(void *stripe_head_ref)
1126 {
1127 struct stripe_head *sh = stripe_head_ref;
1128
1129 pr_debug("%s: stripe %llu\n", __func__,
1130 (unsigned long long)sh->sector);
1131 }
1132
1133 static struct dma_async_tx_descriptor *
1134 ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
1135 struct dma_async_tx_descriptor *tx)
1136 {
1137 int disks = sh->disks;
1138 struct page **xor_srcs = percpu->scribble;
1139 int count = 0, pd_idx = sh->pd_idx, i;
1140 struct async_submit_ctl submit;
1141
1142 /* existing parity data subtracted */
1143 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1144
1145 pr_debug("%s: stripe %llu\n", __func__,
1146 (unsigned long long)sh->sector);
1147
1148 for (i = disks; i--; ) {
1149 struct r5dev *dev = &sh->dev[i];
1150 /* Only process blocks that are known to be uptodate */
1151 if (test_bit(R5_Wantdrain, &dev->flags))
1152 xor_srcs[count++] = dev->page;
1153 }
1154
1155 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1156 ops_complete_prexor, sh, to_addr_conv(sh, percpu));
1157 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1158
1159 return tx;
1160 }
1161
1162 static struct dma_async_tx_descriptor *
1163 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1164 {
1165 int disks = sh->disks;
1166 int i;
1167
1168 pr_debug("%s: stripe %llu\n", __func__,
1169 (unsigned long long)sh->sector);
1170
1171 for (i = disks; i--; ) {
1172 struct r5dev *dev = &sh->dev[i];
1173 struct bio *chosen;
1174
1175 if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
1176 struct bio *wbi;
1177
1178 spin_lock_irq(&sh->stripe_lock);
1179 chosen = dev->towrite;
1180 dev->towrite = NULL;
1181 BUG_ON(dev->written);
1182 wbi = dev->written = chosen;
1183 spin_unlock_irq(&sh->stripe_lock);
1184
1185 while (wbi && wbi->bi_sector <
1186 dev->sector + STRIPE_SECTORS) {
1187 if (wbi->bi_rw & REQ_FUA)
1188 set_bit(R5_WantFUA, &dev->flags);
1189 if (wbi->bi_rw & REQ_SYNC)
1190 set_bit(R5_SyncIO, &dev->flags);
1191 if (wbi->bi_rw & REQ_DISCARD)
1192 set_bit(R5_Discard, &dev->flags);
1193 else
1194 tx = async_copy_data(1, wbi, dev->page,
1195 dev->sector, tx);
1196 wbi = r5_next_bio(wbi, dev->sector);
1197 }
1198 }
1199 }
1200
1201 return tx;
1202 }
1203
1204 static void ops_complete_reconstruct(void *stripe_head_ref)
1205 {
1206 struct stripe_head *sh = stripe_head_ref;
1207 int disks = sh->disks;
1208 int pd_idx = sh->pd_idx;
1209 int qd_idx = sh->qd_idx;
1210 int i;
1211 bool fua = false, sync = false, discard = false;
1212
1213 pr_debug("%s: stripe %llu\n", __func__,
1214 (unsigned long long)sh->sector);
1215
1216 for (i = disks; i--; ) {
1217 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1218 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1219 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1220 }
1221
1222 for (i = disks; i--; ) {
1223 struct r5dev *dev = &sh->dev[i];
1224
1225 if (dev->written || i == pd_idx || i == qd_idx) {
1226 if (!discard)
1227 set_bit(R5_UPTODATE, &dev->flags);
1228 if (fua)
1229 set_bit(R5_WantFUA, &dev->flags);
1230 if (sync)
1231 set_bit(R5_SyncIO, &dev->flags);
1232 }
1233 }
1234
1235 if (sh->reconstruct_state == reconstruct_state_drain_run)
1236 sh->reconstruct_state = reconstruct_state_drain_result;
1237 else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1238 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1239 else {
1240 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1241 sh->reconstruct_state = reconstruct_state_result;
1242 }
1243
1244 set_bit(STRIPE_HANDLE, &sh->state);
1245 release_stripe(sh);
1246 }
1247
1248 static void
1249 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1250 struct dma_async_tx_descriptor *tx)
1251 {
1252 int disks = sh->disks;
1253 struct page **xor_srcs = percpu->scribble;
1254 struct async_submit_ctl submit;
1255 int count = 0, pd_idx = sh->pd_idx, i;
1256 struct page *xor_dest;
1257 int prexor = 0;
1258 unsigned long flags;
1259
1260 pr_debug("%s: stripe %llu\n", __func__,
1261 (unsigned long long)sh->sector);
1262
1263 for (i = 0; i < sh->disks; i++) {
1264 if (pd_idx == i)
1265 continue;
1266 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1267 break;
1268 }
1269 if (i >= sh->disks) {
1270 atomic_inc(&sh->count);
1271 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1272 ops_complete_reconstruct(sh);
1273 return;
1274 }
1275 /* check if prexor is active which means only process blocks
1276 * that are part of a read-modify-write (written)
1277 */
1278 if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1279 prexor = 1;
1280 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1281 for (i = disks; i--; ) {
1282 struct r5dev *dev = &sh->dev[i];
1283 if (dev->written)
1284 xor_srcs[count++] = dev->page;
1285 }
1286 } else {
1287 xor_dest = sh->dev[pd_idx].page;
1288 for (i = disks; i--; ) {
1289 struct r5dev *dev = &sh->dev[i];
1290 if (i != pd_idx)
1291 xor_srcs[count++] = dev->page;
1292 }
1293 }
1294
1295 /* 1/ if we prexor'd then the dest is reused as a source
1296 * 2/ if we did not prexor then we are redoing the parity
1297 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1298 * for the synchronous xor case
1299 */
1300 flags = ASYNC_TX_ACK |
1301 (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1302
1303 atomic_inc(&sh->count);
1304
1305 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
1306 to_addr_conv(sh, percpu));
1307 if (unlikely(count == 1))
1308 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1309 else
1310 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1311 }
1312
1313 static void
1314 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1315 struct dma_async_tx_descriptor *tx)
1316 {
1317 struct async_submit_ctl submit;
1318 struct page **blocks = percpu->scribble;
1319 int count, i;
1320
1321 pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1322
1323 for (i = 0; i < sh->disks; i++) {
1324 if (sh->pd_idx == i || sh->qd_idx == i)
1325 continue;
1326 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1327 break;
1328 }
1329 if (i >= sh->disks) {
1330 atomic_inc(&sh->count);
1331 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1332 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1333 ops_complete_reconstruct(sh);
1334 return;
1335 }
1336
1337 count = set_syndrome_sources(blocks, sh);
1338
1339 atomic_inc(&sh->count);
1340
1341 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct,
1342 sh, to_addr_conv(sh, percpu));
1343 async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1344 }
1345
1346 static void ops_complete_check(void *stripe_head_ref)
1347 {
1348 struct stripe_head *sh = stripe_head_ref;
1349
1350 pr_debug("%s: stripe %llu\n", __func__,
1351 (unsigned long long)sh->sector);
1352
1353 sh->check_state = check_state_check_result;
1354 set_bit(STRIPE_HANDLE, &sh->state);
1355 release_stripe(sh);
1356 }
1357
1358 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1359 {
1360 int disks = sh->disks;
1361 int pd_idx = sh->pd_idx;
1362 int qd_idx = sh->qd_idx;
1363 struct page *xor_dest;
1364 struct page **xor_srcs = percpu->scribble;
1365 struct dma_async_tx_descriptor *tx;
1366 struct async_submit_ctl submit;
1367 int count;
1368 int i;
1369
1370 pr_debug("%s: stripe %llu\n", __func__,
1371 (unsigned long long)sh->sector);
1372
1373 count = 0;
1374 xor_dest = sh->dev[pd_idx].page;
1375 xor_srcs[count++] = xor_dest;
1376 for (i = disks; i--; ) {
1377 if (i == pd_idx || i == qd_idx)
1378 continue;
1379 xor_srcs[count++] = sh->dev[i].page;
1380 }
1381
1382 init_async_submit(&submit, 0, NULL, NULL, NULL,
1383 to_addr_conv(sh, percpu));
1384 tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
1385 &sh->ops.zero_sum_result, &submit);
1386
1387 atomic_inc(&sh->count);
1388 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
1389 tx = async_trigger_callback(&submit);
1390 }
1391
1392 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
1393 {
1394 struct page **srcs = percpu->scribble;
1395 struct async_submit_ctl submit;
1396 int count;
1397
1398 pr_debug("%s: stripe %llu checkp: %d\n", __func__,
1399 (unsigned long long)sh->sector, checkp);
1400
1401 count = set_syndrome_sources(srcs, sh);
1402 if (!checkp)
1403 srcs[count] = NULL;
1404
1405 atomic_inc(&sh->count);
1406 init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
1407 sh, to_addr_conv(sh, percpu));
1408 async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
1409 &sh->ops.zero_sum_result, percpu->spare_page, &submit);
1410 }
1411
1412 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1413 {
1414 int overlap_clear = 0, i, disks = sh->disks;
1415 struct dma_async_tx_descriptor *tx = NULL;
1416 struct r5conf *conf = sh->raid_conf;
1417 int level = conf->level;
1418 struct raid5_percpu *percpu;
1419 unsigned long cpu;
1420
1421 cpu = get_cpu();
1422 percpu = per_cpu_ptr(conf->percpu, cpu);
1423 if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
1424 ops_run_biofill(sh);
1425 overlap_clear++;
1426 }
1427
1428 if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
1429 if (level < 6)
1430 tx = ops_run_compute5(sh, percpu);
1431 else {
1432 if (sh->ops.target2 < 0 || sh->ops.target < 0)
1433 tx = ops_run_compute6_1(sh, percpu);
1434 else
1435 tx = ops_run_compute6_2(sh, percpu);
1436 }
1437 /* terminate the chain if reconstruct is not set to be run */
1438 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
1439 async_tx_ack(tx);
1440 }
1441
1442 if (test_bit(STRIPE_OP_PREXOR, &ops_request))
1443 tx = ops_run_prexor(sh, percpu, tx);
1444
1445 if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
1446 tx = ops_run_biodrain(sh, tx);
1447 overlap_clear++;
1448 }
1449
1450 if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
1451 if (level < 6)
1452 ops_run_reconstruct5(sh, percpu, tx);
1453 else
1454 ops_run_reconstruct6(sh, percpu, tx);
1455 }
1456
1457 if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
1458 if (sh->check_state == check_state_run)
1459 ops_run_check_p(sh, percpu);
1460 else if (sh->check_state == check_state_run_q)
1461 ops_run_check_pq(sh, percpu, 0);
1462 else if (sh->check_state == check_state_run_pq)
1463 ops_run_check_pq(sh, percpu, 1);
1464 else
1465 BUG();
1466 }
1467
1468 if (overlap_clear)
1469 for (i = disks; i--; ) {
1470 struct r5dev *dev = &sh->dev[i];
1471 if (test_and_clear_bit(R5_Overlap, &dev->flags))
1472 wake_up(&sh->raid_conf->wait_for_overlap);
1473 }
1474 put_cpu();
1475 }
1476
1477 static int grow_one_stripe(struct r5conf *conf)
1478 {
1479 struct stripe_head *sh;
1480 sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL);
1481 if (!sh)
1482 return 0;
1483
1484 sh->raid_conf = conf;
1485
1486 spin_lock_init(&sh->stripe_lock);
1487
1488 if (grow_buffers(sh)) {
1489 shrink_buffers(sh);
1490 kmem_cache_free(conf->slab_cache, sh);
1491 return 0;
1492 }
1493 /* we just created an active stripe so... */
1494 atomic_set(&sh->count, 1);
1495 atomic_inc(&conf->active_stripes);
1496 INIT_LIST_HEAD(&sh->lru);
1497 release_stripe(sh);
1498 return 1;
1499 }
1500
1501 static int grow_stripes(struct r5conf *conf, int num)
1502 {
1503 struct kmem_cache *sc;
1504 int devs = max(conf->raid_disks, conf->previous_raid_disks);
1505
1506 if (conf->mddev->gendisk)
1507 sprintf(conf->cache_name[0],
1508 "raid%d-%s", conf->level, mdname(conf->mddev));
1509 else
1510 sprintf(conf->cache_name[0],
1511 "raid%d-%p", conf->level, conf->mddev);
1512 sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
1513
1514 conf->active_name = 0;
1515 sc = kmem_cache_create(conf->cache_name[conf->active_name],
1516 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
1517 0, 0, NULL);
1518 if (!sc)
1519 return 1;
1520 conf->slab_cache = sc;
1521 conf->pool_size = devs;
1522 while (num--)
1523 if (!grow_one_stripe(conf))
1524 return 1;
1525 return 0;
1526 }
1527
1528 /**
1529 * scribble_len - return the required size of the scribble region
1530 * @num - total number of disks in the array
1531 *
1532 * The size must be enough to contain:
1533 * 1/ a struct page pointer for each device in the array +2
1534 * 2/ room to convert each entry in (1) to its corresponding dma
1535 * (dma_map_page()) or page (page_address()) address.
1536 *
1537 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
1538 * calculate over all devices (not just the data blocks), using zeros in place
1539 * of the P and Q blocks.
1540 */
1541 static size_t scribble_len(int num)
1542 {
1543 size_t len;
1544
1545 len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
1546
1547 return len;
1548 }
1549
1550 static int resize_stripes(struct r5conf *conf, int newsize)
1551 {
1552 /* Make all the stripes able to hold 'newsize' devices.
1553 * New slots in each stripe get 'page' set to a new page.
1554 *
1555 * This happens in stages:
1556 * 1/ create a new kmem_cache and allocate the required number of
1557 * stripe_heads.
1558 * 2/ gather all the old stripe_heads and transfer the pages across
1559 * to the new stripe_heads. This will have the side effect of
1560 * freezing the array as once all stripe_heads have been collected,
1561 * no IO will be possible. Old stripe heads are freed once their
1562 * pages have been transferred over, and the old kmem_cache is
1563 * freed when all stripes are done.
1564 * 3/ reallocate conf->disks to be suitable bigger. If this fails,
1565 * we simple return a failre status - no need to clean anything up.
1566 * 4/ allocate new pages for the new slots in the new stripe_heads.
1567 * If this fails, we don't bother trying the shrink the
1568 * stripe_heads down again, we just leave them as they are.
1569 * As each stripe_head is processed the new one is released into
1570 * active service.
1571 *
1572 * Once step2 is started, we cannot afford to wait for a write,
1573 * so we use GFP_NOIO allocations.
1574 */
1575 struct stripe_head *osh, *nsh;
1576 LIST_HEAD(newstripes);
1577 struct disk_info *ndisks;
1578 unsigned long cpu;
1579 int err;
1580 struct kmem_cache *sc;
1581 int i;
1582
1583 if (newsize <= conf->pool_size)
1584 return 0; /* never bother to shrink */
1585
1586 err = md_allow_write(conf->mddev);
1587 if (err)
1588 return err;
1589
1590 /* Step 1 */
1591 sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
1592 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1593 0, 0, NULL);
1594 if (!sc)
1595 return -ENOMEM;
1596
1597 for (i = conf->max_nr_stripes; i; i--) {
1598 nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
1599 if (!nsh)
1600 break;
1601
1602 nsh->raid_conf = conf;
1603 spin_lock_init(&nsh->stripe_lock);
1604
1605 list_add(&nsh->lru, &newstripes);
1606 }
1607 if (i) {
1608 /* didn't get enough, give up */
1609 while (!list_empty(&newstripes)) {
1610 nsh = list_entry(newstripes.next, struct stripe_head, lru);
1611 list_del(&nsh->lru);
1612 kmem_cache_free(sc, nsh);
1613 }
1614 kmem_cache_destroy(sc);
1615 return -ENOMEM;
1616 }
1617 /* Step 2 - Must use GFP_NOIO now.
1618 * OK, we have enough stripes, start collecting inactive
1619 * stripes and copying them over
1620 */
1621 list_for_each_entry(nsh, &newstripes, lru) {
1622 spin_lock_irq(&conf->device_lock);
1623 wait_event_lock_irq(conf->wait_for_stripe,
1624 !list_empty(&conf->inactive_list),
1625 conf->device_lock);
1626 osh = get_free_stripe(conf);
1627 spin_unlock_irq(&conf->device_lock);
1628 atomic_set(&nsh->count, 1);
1629 for(i=0; i<conf->pool_size; i++)
1630 nsh->dev[i].page = osh->dev[i].page;
1631 for( ; i<newsize; i++)
1632 nsh->dev[i].page = NULL;
1633 kmem_cache_free(conf->slab_cache, osh);
1634 }
1635 kmem_cache_destroy(conf->slab_cache);
1636
1637 /* Step 3.
1638 * At this point, we are holding all the stripes so the array
1639 * is completely stalled, so now is a good time to resize
1640 * conf->disks and the scribble region
1641 */
1642 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
1643 if (ndisks) {
1644 for (i=0; i<conf->raid_disks; i++)
1645 ndisks[i] = conf->disks[i];
1646 kfree(conf->disks);
1647 conf->disks = ndisks;
1648 } else
1649 err = -ENOMEM;
1650
1651 get_online_cpus();
1652 conf->scribble_len = scribble_len(newsize);
1653 for_each_present_cpu(cpu) {
1654 struct raid5_percpu *percpu;
1655 void *scribble;
1656
1657 percpu = per_cpu_ptr(conf->percpu, cpu);
1658 scribble = kmalloc(conf->scribble_len, GFP_NOIO);
1659
1660 if (scribble) {
1661 kfree(percpu->scribble);
1662 percpu->scribble = scribble;
1663 } else {
1664 err = -ENOMEM;
1665 break;
1666 }
1667 }
1668 put_online_cpus();
1669
1670 /* Step 4, return new stripes to service */
1671 while(!list_empty(&newstripes)) {
1672 nsh = list_entry(newstripes.next, struct stripe_head, lru);
1673 list_del_init(&nsh->lru);
1674
1675 for (i=conf->raid_disks; i < newsize; i++)
1676 if (nsh->dev[i].page == NULL) {
1677 struct page *p = alloc_page(GFP_NOIO);
1678 nsh->dev[i].page = p;
1679 if (!p)
1680 err = -ENOMEM;
1681 }
1682 release_stripe(nsh);
1683 }
1684 /* critical section pass, GFP_NOIO no longer needed */
1685
1686 conf->slab_cache = sc;
1687 conf->active_name = 1-conf->active_name;
1688 conf->pool_size = newsize;
1689 return err;
1690 }
1691
1692 static int drop_one_stripe(struct r5conf *conf)
1693 {
1694 struct stripe_head *sh;
1695
1696 spin_lock_irq(&conf->device_lock);
1697 sh = get_free_stripe(conf);
1698 spin_unlock_irq(&conf->device_lock);
1699 if (!sh)
1700 return 0;
1701 BUG_ON(atomic_read(&sh->count));
1702 shrink_buffers(sh);
1703 kmem_cache_free(conf->slab_cache, sh);
1704 atomic_dec(&conf->active_stripes);
1705 return 1;
1706 }
1707
1708 static void shrink_stripes(struct r5conf *conf)
1709 {
1710 while (drop_one_stripe(conf))
1711 ;
1712
1713 if (conf->slab_cache)
1714 kmem_cache_destroy(conf->slab_cache);
1715 conf->slab_cache = NULL;
1716 }
1717
1718 static void raid5_end_read_request(struct bio * bi, int error)
1719 {
1720 struct stripe_head *sh = bi->bi_private;
1721 struct r5conf *conf = sh->raid_conf;
1722 int disks = sh->disks, i;
1723 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1724 char b[BDEVNAME_SIZE];
1725 struct md_rdev *rdev = NULL;
1726 sector_t s;
1727
1728 for (i=0 ; i<disks; i++)
1729 if (bi == &sh->dev[i].req)
1730 break;
1731
1732 pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
1733 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
1734 uptodate);
1735 if (i == disks) {
1736 BUG();
1737 return;
1738 }
1739 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
1740 /* If replacement finished while this request was outstanding,
1741 * 'replacement' might be NULL already.
1742 * In that case it moved down to 'rdev'.
1743 * rdev is not removed until all requests are finished.
1744 */
1745 rdev = conf->disks[i].replacement;
1746 if (!rdev)
1747 rdev = conf->disks[i].rdev;
1748
1749 if (use_new_offset(conf, sh))
1750 s = sh->sector + rdev->new_data_offset;
1751 else
1752 s = sh->sector + rdev->data_offset;
1753 if (uptodate) {
1754 set_bit(R5_UPTODATE, &sh->dev[i].flags);
1755 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1756 /* Note that this cannot happen on a
1757 * replacement device. We just fail those on
1758 * any error
1759 */
1760 printk_ratelimited(
1761 KERN_INFO
1762 "md/raid:%s: read error corrected"
1763 " (%lu sectors at %llu on %s)\n",
1764 mdname(conf->mddev), STRIPE_SECTORS,
1765 (unsigned long long)s,
1766 bdevname(rdev->bdev, b));
1767 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1768 clear_bit(R5_ReadError, &sh->dev[i].flags);
1769 clear_bit(R5_ReWrite, &sh->dev[i].flags);
1770 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
1771 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
1772
1773 if (atomic_read(&rdev->read_errors))
1774 atomic_set(&rdev->read_errors, 0);
1775 } else {
1776 const char *bdn = bdevname(rdev->bdev, b);
1777 int retry = 0;
1778 int set_bad = 0;
1779
1780 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1781 atomic_inc(&rdev->read_errors);
1782 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
1783 printk_ratelimited(
1784 KERN_WARNING
1785 "md/raid:%s: read error on replacement device "
1786 "(sector %llu on %s).\n",
1787 mdname(conf->mddev),
1788 (unsigned long long)s,
1789 bdn);
1790 else if (conf->mddev->degraded >= conf->max_degraded) {
1791 set_bad = 1;
1792 printk_ratelimited(
1793 KERN_WARNING
1794 "md/raid:%s: read error not correctable "
1795 "(sector %llu on %s).\n",
1796 mdname(conf->mddev),
1797 (unsigned long long)s,
1798 bdn);
1799 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
1800 /* Oh, no!!! */
1801 set_bad = 1;
1802 printk_ratelimited(
1803 KERN_WARNING
1804 "md/raid:%s: read error NOT corrected!! "
1805 "(sector %llu on %s).\n",
1806 mdname(conf->mddev),
1807 (unsigned long long)s,
1808 bdn);
1809 } else if (atomic_read(&rdev->read_errors)
1810 > conf->max_nr_stripes)
1811 printk(KERN_WARNING
1812 "md/raid:%s: Too many read errors, failing device %s.\n",
1813 mdname(conf->mddev), bdn);
1814 else
1815 retry = 1;
1816 if (retry)
1817 if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
1818 set_bit(R5_ReadError, &sh->dev[i].flags);
1819 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
1820 } else
1821 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
1822 else {
1823 clear_bit(R5_ReadError, &sh->dev[i].flags);
1824 clear_bit(R5_ReWrite, &sh->dev[i].flags);
1825 if (!(set_bad
1826 && test_bit(In_sync, &rdev->flags)
1827 && rdev_set_badblocks(
1828 rdev, sh->sector, STRIPE_SECTORS, 0)))
1829 md_error(conf->mddev, rdev);
1830 }
1831 }
1832 rdev_dec_pending(rdev, conf->mddev);
1833 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1834 set_bit(STRIPE_HANDLE, &sh->state);
1835 release_stripe(sh);
1836 }
1837
1838 static void raid5_end_write_request(struct bio *bi, int error)
1839 {
1840 struct stripe_head *sh = bi->bi_private;
1841 struct r5conf *conf = sh->raid_conf;
1842 int disks = sh->disks, i;
1843 struct md_rdev *uninitialized_var(rdev);
1844 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1845 sector_t first_bad;
1846 int bad_sectors;
1847 int replacement = 0;
1848
1849 for (i = 0 ; i < disks; i++) {
1850 if (bi == &sh->dev[i].req) {
1851 rdev = conf->disks[i].rdev;
1852 break;
1853 }
1854 if (bi == &sh->dev[i].rreq) {
1855 rdev = conf->disks[i].replacement;
1856 if (rdev)
1857 replacement = 1;
1858 else
1859 /* rdev was removed and 'replacement'
1860 * replaced it. rdev is not removed
1861 * until all requests are finished.
1862 */
1863 rdev = conf->disks[i].rdev;
1864 break;
1865 }
1866 }
1867 pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
1868 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
1869 uptodate);
1870 if (i == disks) {
1871 BUG();
1872 return;
1873 }
1874
1875 if (replacement) {
1876 if (!uptodate)
1877 md_error(conf->mddev, rdev);
1878 else if (is_badblock(rdev, sh->sector,
1879 STRIPE_SECTORS,
1880 &first_bad, &bad_sectors))
1881 set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
1882 } else {
1883 if (!uptodate) {
1884 set_bit(WriteErrorSeen, &rdev->flags);
1885 set_bit(R5_WriteError, &sh->dev[i].flags);
1886 if (!test_and_set_bit(WantReplacement, &rdev->flags))
1887 set_bit(MD_RECOVERY_NEEDED,
1888 &rdev->mddev->recovery);
1889 } else if (is_badblock(rdev, sh->sector,
1890 STRIPE_SECTORS,
1891 &first_bad, &bad_sectors)) {
1892 set_bit(R5_MadeGood, &sh->dev[i].flags);
1893 if (test_bit(R5_ReadError, &sh->dev[i].flags))
1894 /* That was a successful write so make
1895 * sure it looks like we already did
1896 * a re-write.
1897 */
1898 set_bit(R5_ReWrite, &sh->dev[i].flags);
1899 }
1900 }
1901 rdev_dec_pending(rdev, conf->mddev);
1902
1903 if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
1904 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1905 set_bit(STRIPE_HANDLE, &sh->state);
1906 release_stripe(sh);
1907 }
1908
1909 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
1910
1911 static void raid5_build_block(struct stripe_head *sh, int i, int previous)
1912 {
1913 struct r5dev *dev = &sh->dev[i];
1914
1915 bio_init(&dev->req);
1916 dev->req.bi_io_vec = &dev->vec;
1917 dev->req.bi_vcnt++;
1918 dev->req.bi_max_vecs++;
1919 dev->req.bi_private = sh;
1920 dev->vec.bv_page = dev->page;
1921
1922 bio_init(&dev->rreq);
1923 dev->rreq.bi_io_vec = &dev->rvec;
1924 dev->rreq.bi_vcnt++;
1925 dev->rreq.bi_max_vecs++;
1926 dev->rreq.bi_private = sh;
1927 dev->rvec.bv_page = dev->page;
1928
1929 dev->flags = 0;
1930 dev->sector = compute_blocknr(sh, i, previous);
1931 }
1932
1933 static void error(struct mddev *mddev, struct md_rdev *rdev)
1934 {
1935 char b[BDEVNAME_SIZE];
1936 struct r5conf *conf = mddev->private;
1937 unsigned long flags;
1938 pr_debug("raid456: error called\n");
1939
1940 spin_lock_irqsave(&conf->device_lock, flags);
1941 clear_bit(In_sync, &rdev->flags);
1942 mddev->degraded = calc_degraded(conf);
1943 spin_unlock_irqrestore(&conf->device_lock, flags);
1944 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1945
1946 set_bit(Blocked, &rdev->flags);
1947 set_bit(Faulty, &rdev->flags);
1948 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1949 printk(KERN_ALERT
1950 "md/raid:%s: Disk failure on %s, disabling device.\n"
1951 "md/raid:%s: Operation continuing on %d devices.\n",
1952 mdname(mddev),
1953 bdevname(rdev->bdev, b),
1954 mdname(mddev),
1955 conf->raid_disks - mddev->degraded);
1956 }
1957
1958 /*
1959 * Input: a 'big' sector number,
1960 * Output: index of the data and parity disk, and the sector # in them.
1961 */
1962 static sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
1963 int previous, int *dd_idx,
1964 struct stripe_head *sh)
1965 {
1966 sector_t stripe, stripe2;
1967 sector_t chunk_number;
1968 unsigned int chunk_offset;
1969 int pd_idx, qd_idx;
1970 int ddf_layout = 0;
1971 sector_t new_sector;
1972 int algorithm = previous ? conf->prev_algo
1973 : conf->algorithm;
1974 int sectors_per_chunk = previous ? conf->prev_chunk_sectors
1975 : conf->chunk_sectors;
1976 int raid_disks = previous ? conf->previous_raid_disks
1977 : conf->raid_disks;
1978 int data_disks = raid_disks - conf->max_degraded;
1979
1980 /* First compute the information on this sector */
1981
1982 /*
1983 * Compute the chunk number and the sector offset inside the chunk
1984 */
1985 chunk_offset = sector_div(r_sector, sectors_per_chunk);
1986 chunk_number = r_sector;
1987
1988 /*
1989 * Compute the stripe number
1990 */
1991 stripe = chunk_number;
1992 *dd_idx = sector_div(stripe, data_disks);
1993 stripe2 = stripe;
1994 /*
1995 * Select the parity disk based on the user selected algorithm.
1996 */
1997 pd_idx = qd_idx = -1;
1998 switch(conf->level) {
1999 case 4:
2000 pd_idx = data_disks;
2001 break;
2002 case 5:
2003 switch (algorithm) {
2004 case ALGORITHM_LEFT_ASYMMETRIC:
2005 pd_idx = data_disks - sector_div(stripe2, raid_disks);
2006 if (*dd_idx >= pd_idx)
2007 (*dd_idx)++;
2008 break;
2009 case ALGORITHM_RIGHT_ASYMMETRIC:
2010 pd_idx = sector_div(stripe2, raid_disks);
2011 if (*dd_idx >= pd_idx)
2012 (*dd_idx)++;
2013 break;
2014 case ALGORITHM_LEFT_SYMMETRIC:
2015 pd_idx = data_disks - sector_div(stripe2, raid_disks);
2016 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2017 break;
2018 case ALGORITHM_RIGHT_SYMMETRIC:
2019 pd_idx = sector_div(stripe2, raid_disks);
2020 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2021 break;
2022 case ALGORITHM_PARITY_0:
2023 pd_idx = 0;
2024 (*dd_idx)++;
2025 break;
2026 case ALGORITHM_PARITY_N:
2027 pd_idx = data_disks;
2028 break;
2029 default:
2030 BUG();
2031 }
2032 break;
2033 case 6:
2034
2035 switch (algorithm) {
2036 case ALGORITHM_LEFT_ASYMMETRIC:
2037 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2038 qd_idx = pd_idx + 1;
2039 if (pd_idx == raid_disks-1) {
2040 (*dd_idx)++; /* Q D D D P */
2041 qd_idx = 0;
2042 } else if (*dd_idx >= pd_idx)
2043 (*dd_idx) += 2; /* D D P Q D */
2044 break;
2045 case ALGORITHM_RIGHT_ASYMMETRIC:
2046 pd_idx = sector_div(stripe2, raid_disks);
2047 qd_idx = pd_idx + 1;
2048 if (pd_idx == raid_disks-1) {
2049 (*dd_idx)++; /* Q D D D P */
2050 qd_idx = 0;
2051 } else if (*dd_idx >= pd_idx)
2052 (*dd_idx) += 2; /* D D P Q D */
2053 break;
2054 case ALGORITHM_LEFT_SYMMETRIC:
2055 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2056 qd_idx = (pd_idx + 1) % raid_disks;
2057 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2058 break;
2059 case ALGORITHM_RIGHT_SYMMETRIC:
2060 pd_idx = sector_div(stripe2, raid_disks);
2061 qd_idx = (pd_idx + 1) % raid_disks;
2062 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2063 break;
2064
2065 case ALGORITHM_PARITY_0:
2066 pd_idx = 0;
2067 qd_idx = 1;
2068 (*dd_idx) += 2;
2069 break;
2070 case ALGORITHM_PARITY_N:
2071 pd_idx = data_disks;
2072 qd_idx = data_disks + 1;
2073 break;
2074
2075 case ALGORITHM_ROTATING_ZERO_RESTART:
2076 /* Exactly the same as RIGHT_ASYMMETRIC, but or
2077 * of blocks for computing Q is different.
2078 */
2079 pd_idx = sector_div(stripe2, raid_disks);
2080 qd_idx = pd_idx + 1;
2081 if (pd_idx == raid_disks-1) {
2082 (*dd_idx)++; /* Q D D D P */
2083 qd_idx = 0;
2084 } else if (*dd_idx >= pd_idx)
2085 (*dd_idx) += 2; /* D D P Q D */
2086 ddf_layout = 1;
2087 break;
2088
2089 case ALGORITHM_ROTATING_N_RESTART:
2090 /* Same a left_asymmetric, by first stripe is
2091 * D D D P Q rather than
2092 * Q D D D P
2093 */
2094 stripe2 += 1;
2095 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2096 qd_idx = pd_idx + 1;
2097 if (pd_idx == raid_disks-1) {
2098 (*dd_idx)++; /* Q D D D P */
2099 qd_idx = 0;
2100 } else if (*dd_idx >= pd_idx)
2101 (*dd_idx) += 2; /* D D P Q D */
2102 ddf_layout = 1;
2103 break;
2104
2105 case ALGORITHM_ROTATING_N_CONTINUE:
2106 /* Same as left_symmetric but Q is before P */
2107 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2108 qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2109 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2110 ddf_layout = 1;
2111 break;
2112
2113 case ALGORITHM_LEFT_ASYMMETRIC_6:
2114 /* RAID5 left_asymmetric, with Q on last device */
2115 pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2116 if (*dd_idx >= pd_idx)
2117 (*dd_idx)++;
2118 qd_idx = raid_disks - 1;
2119 break;
2120
2121 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2122 pd_idx = sector_div(stripe2, raid_disks-1);
2123 if (*dd_idx >= pd_idx)
2124 (*dd_idx)++;
2125 qd_idx = raid_disks - 1;
2126 break;
2127
2128 case ALGORITHM_LEFT_SYMMETRIC_6:
2129 pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2130 *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2131 qd_idx = raid_disks - 1;
2132 break;
2133
2134 case ALGORITHM_RIGHT_SYMMETRIC_6:
2135 pd_idx = sector_div(stripe2, raid_disks-1);
2136 *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2137 qd_idx = raid_disks - 1;
2138 break;
2139
2140 case ALGORITHM_PARITY_0_6:
2141 pd_idx = 0;
2142 (*dd_idx)++;
2143 qd_idx = raid_disks - 1;
2144 break;
2145
2146 default:
2147 BUG();
2148 }
2149 break;
2150 }
2151
2152 if (sh) {
2153 sh->pd_idx = pd_idx;
2154 sh->qd_idx = qd_idx;
2155 sh->ddf_layout = ddf_layout;
2156 }
2157 /*
2158 * Finally, compute the new sector number
2159 */
2160 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2161 return new_sector;
2162 }
2163
2164
2165 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
2166 {
2167 struct r5conf *conf = sh->raid_conf;
2168 int raid_disks = sh->disks;
2169 int data_disks = raid_disks - conf->max_degraded;
2170 sector_t new_sector = sh->sector, check;
2171 int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2172 : conf->chunk_sectors;
2173 int algorithm = previous ? conf->prev_algo
2174 : conf->algorithm;
2175 sector_t stripe;
2176 int chunk_offset;
2177 sector_t chunk_number;
2178 int dummy1, dd_idx = i;
2179 sector_t r_sector;
2180 struct stripe_head sh2;
2181
2182
2183 chunk_offset = sector_div(new_sector, sectors_per_chunk);
2184 stripe = new_sector;
2185
2186 if (i == sh->pd_idx)
2187 return 0;
2188 switch(conf->level) {
2189 case 4: break;
2190 case 5:
2191 switch (algorithm) {
2192 case ALGORITHM_LEFT_ASYMMETRIC:
2193 case ALGORITHM_RIGHT_ASYMMETRIC:
2194 if (i > sh->pd_idx)
2195 i--;
2196 break;
2197 case ALGORITHM_LEFT_SYMMETRIC:
2198 case ALGORITHM_RIGHT_SYMMETRIC:
2199 if (i < sh->pd_idx)
2200 i += raid_disks;
2201 i -= (sh->pd_idx + 1);
2202 break;
2203 case ALGORITHM_PARITY_0:
2204 i -= 1;
2205 break;
2206 case ALGORITHM_PARITY_N:
2207 break;
2208 default:
2209 BUG();
2210 }
2211 break;
2212 case 6:
2213 if (i == sh->qd_idx)
2214 return 0; /* It is the Q disk */
2215 switch (algorithm) {
2216 case ALGORITHM_LEFT_ASYMMETRIC:
2217 case ALGORITHM_RIGHT_ASYMMETRIC:
2218 case ALGORITHM_ROTATING_ZERO_RESTART:
2219 case ALGORITHM_ROTATING_N_RESTART:
2220 if (sh->pd_idx == raid_disks-1)
2221 i--; /* Q D D D P */
2222 else if (i > sh->pd_idx)
2223 i -= 2; /* D D P Q D */
2224 break;
2225 case ALGORITHM_LEFT_SYMMETRIC:
2226 case ALGORITHM_RIGHT_SYMMETRIC:
2227 if (sh->pd_idx == raid_disks-1)
2228 i--; /* Q D D D P */
2229 else {
2230 /* D D P Q D */
2231 if (i < sh->pd_idx)
2232 i += raid_disks;
2233 i -= (sh->pd_idx + 2);
2234 }
2235 break;
2236 case ALGORITHM_PARITY_0:
2237 i -= 2;
2238 break;
2239 case ALGORITHM_PARITY_N:
2240 break;
2241 case ALGORITHM_ROTATING_N_CONTINUE:
2242 /* Like left_symmetric, but P is before Q */
2243 if (sh->pd_idx == 0)
2244 i--; /* P D D D Q */
2245 else {
2246 /* D D Q P D */
2247 if (i < sh->pd_idx)
2248 i += raid_disks;
2249 i -= (sh->pd_idx + 1);
2250 }
2251 break;
2252 case ALGORITHM_LEFT_ASYMMETRIC_6:
2253 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2254 if (i > sh->pd_idx)
2255 i--;
2256 break;
2257 case ALGORITHM_LEFT_SYMMETRIC_6:
2258 case ALGORITHM_RIGHT_SYMMETRIC_6:
2259 if (i < sh->pd_idx)
2260 i += data_disks + 1;
2261 i -= (sh->pd_idx + 1);
2262 break;
2263 case ALGORITHM_PARITY_0_6:
2264 i -= 1;
2265 break;
2266 default:
2267 BUG();
2268 }
2269 break;
2270 }
2271
2272 chunk_number = stripe * data_disks + i;
2273 r_sector = chunk_number * sectors_per_chunk + chunk_offset;
2274
2275 check = raid5_compute_sector(conf, r_sector,
2276 previous, &dummy1, &sh2);
2277 if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
2278 || sh2.qd_idx != sh->qd_idx) {
2279 printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
2280 mdname(conf->mddev));
2281 return 0;
2282 }
2283 return r_sector;
2284 }
2285
2286
2287 static void
2288 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
2289 int rcw, int expand)
2290 {
2291 int i, pd_idx = sh->pd_idx, disks = sh->disks;
2292 struct r5conf *conf = sh->raid_conf;
2293 int level = conf->level;
2294
2295 if (rcw) {
2296
2297 for (i = disks; i--; ) {
2298 struct r5dev *dev = &sh->dev[i];
2299
2300 if (dev->towrite) {
2301 set_bit(R5_LOCKED, &dev->flags);
2302 set_bit(R5_Wantdrain, &dev->flags);
2303 if (!expand)
2304 clear_bit(R5_UPTODATE, &dev->flags);
2305 s->locked++;
2306 }
2307 }
2308 /* if we are not expanding this is a proper write request, and
2309 * there will be bios with new data to be drained into the
2310 * stripe cache
2311 */
2312 if (!expand) {
2313 if (!s->locked)
2314 /* False alarm, nothing to do */
2315 return;
2316 sh->reconstruct_state = reconstruct_state_drain_run;
2317 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2318 } else
2319 sh->reconstruct_state = reconstruct_state_run;
2320
2321 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2322
2323 if (s->locked + conf->max_degraded == disks)
2324 if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2325 atomic_inc(&conf->pending_full_writes);
2326 } else {
2327 BUG_ON(level == 6);
2328 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
2329 test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
2330
2331 for (i = disks; i--; ) {
2332 struct r5dev *dev = &sh->dev[i];
2333 if (i == pd_idx)
2334 continue;
2335
2336 if (dev->towrite &&
2337 (test_bit(R5_UPTODATE, &dev->flags) ||
2338 test_bit(R5_Wantcompute, &dev->flags))) {
2339 set_bit(R5_Wantdrain, &dev->flags);
2340 set_bit(R5_LOCKED, &dev->flags);
2341 clear_bit(R5_UPTODATE, &dev->flags);
2342 s->locked++;
2343 }
2344 }
2345 if (!s->locked)
2346 /* False alarm - nothing to do */
2347 return;
2348 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
2349 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
2350 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2351 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2352 }
2353
2354 /* keep the parity disk(s) locked while asynchronous operations
2355 * are in flight
2356 */
2357 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
2358 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2359 s->locked++;
2360
2361 if (level == 6) {
2362 int qd_idx = sh->qd_idx;
2363 struct r5dev *dev = &sh->dev[qd_idx];
2364
2365 set_bit(R5_LOCKED, &dev->flags);
2366 clear_bit(R5_UPTODATE, &dev->flags);
2367 s->locked++;
2368 }
2369
2370 pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2371 __func__, (unsigned long long)sh->sector,
2372 s->locked, s->ops_request);
2373 }
2374
2375 /*
2376 * Each stripe/dev can have one or more bion attached.
2377 * toread/towrite point to the first in a chain.
2378 * The bi_next chain must be in order.
2379 */
2380 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
2381 {
2382 struct bio **bip;
2383 struct r5conf *conf = sh->raid_conf;
2384 int firstwrite=0;
2385
2386 pr_debug("adding bi b#%llu to stripe s#%llu\n",
2387 (unsigned long long)bi->bi_sector,
2388 (unsigned long long)sh->sector);
2389
2390 /*
2391 * If several bio share a stripe. The bio bi_phys_segments acts as a
2392 * reference count to avoid race. The reference count should already be
2393 * increased before this function is called (for example, in
2394 * make_request()), so other bio sharing this stripe will not free the
2395 * stripe. If a stripe is owned by one stripe, the stripe lock will
2396 * protect it.
2397 */
2398 spin_lock_irq(&sh->stripe_lock);
2399 if (forwrite) {
2400 bip = &sh->dev[dd_idx].towrite;
2401 if (*bip == NULL)
2402 firstwrite = 1;
2403 } else
2404 bip = &sh->dev[dd_idx].toread;
2405 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
2406 if (bio_end_sector(*bip) > bi->bi_sector)
2407 goto overlap;
2408 bip = & (*bip)->bi_next;
2409 }
2410 if (*bip && (*bip)->bi_sector < bio_end_sector(bi))
2411 goto overlap;
2412
2413 BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
2414 if (*bip)
2415 bi->bi_next = *bip;
2416 *bip = bi;
2417 raid5_inc_bi_active_stripes(bi);
2418
2419 if (forwrite) {
2420 /* check if page is covered */
2421 sector_t sector = sh->dev[dd_idx].sector;
2422 for (bi=sh->dev[dd_idx].towrite;
2423 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
2424 bi && bi->bi_sector <= sector;
2425 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
2426 if (bio_end_sector(bi) >= sector)
2427 sector = bio_end_sector(bi);
2428 }
2429 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
2430 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
2431 }
2432
2433 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
2434 (unsigned long long)(*bip)->bi_sector,
2435 (unsigned long long)sh->sector, dd_idx);
2436 spin_unlock_irq(&sh->stripe_lock);
2437
2438 if (conf->mddev->bitmap && firstwrite) {
2439 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
2440 STRIPE_SECTORS, 0);
2441 sh->bm_seq = conf->seq_flush+1;
2442 set_bit(STRIPE_BIT_DELAY, &sh->state);
2443 }
2444 return 1;
2445
2446 overlap:
2447 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
2448 spin_unlock_irq(&sh->stripe_lock);
2449 return 0;
2450 }
2451
2452 static void end_reshape(struct r5conf *conf);
2453
2454 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
2455 struct stripe_head *sh)
2456 {
2457 int sectors_per_chunk =
2458 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
2459 int dd_idx;
2460 int chunk_offset = sector_div(stripe, sectors_per_chunk);
2461 int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2462
2463 raid5_compute_sector(conf,
2464 stripe * (disks - conf->max_degraded)
2465 *sectors_per_chunk + chunk_offset,
2466 previous,
2467 &dd_idx, sh);
2468 }
2469
2470 static void
2471 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
2472 struct stripe_head_state *s, int disks,
2473 struct bio **return_bi)
2474 {
2475 int i;
2476 for (i = disks; i--; ) {
2477 struct bio *bi;
2478 int bitmap_end = 0;
2479
2480 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2481 struct md_rdev *rdev;
2482 rcu_read_lock();
2483 rdev = rcu_dereference(conf->disks[i].rdev);
2484 if (rdev && test_bit(In_sync, &rdev->flags))
2485 atomic_inc(&rdev->nr_pending);
2486 else
2487 rdev = NULL;
2488 rcu_read_unlock();
2489 if (rdev) {
2490 if (!rdev_set_badblocks(
2491 rdev,
2492 sh->sector,
2493 STRIPE_SECTORS, 0))
2494 md_error(conf->mddev, rdev);
2495 rdev_dec_pending(rdev, conf->mddev);
2496 }
2497 }
2498 spin_lock_irq(&sh->stripe_lock);
2499 /* fail all writes first */
2500 bi = sh->dev[i].towrite;
2501 sh->dev[i].towrite = NULL;
2502 spin_unlock_irq(&sh->stripe_lock);
2503 if (bi)
2504 bitmap_end = 1;
2505
2506 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
2507 wake_up(&conf->wait_for_overlap);
2508
2509 while (bi && bi->bi_sector <
2510 sh->dev[i].sector + STRIPE_SECTORS) {
2511 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
2512 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2513 if (!raid5_dec_bi_active_stripes(bi)) {
2514 md_write_end(conf->mddev);
2515 bi->bi_next = *return_bi;
2516 *return_bi = bi;
2517 }
2518 bi = nextbi;
2519 }
2520 if (bitmap_end)
2521 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
2522 STRIPE_SECTORS, 0, 0);
2523 bitmap_end = 0;
2524 /* and fail all 'written' */
2525 bi = sh->dev[i].written;
2526 sh->dev[i].written = NULL;
2527 if (bi) bitmap_end = 1;
2528 while (bi && bi->bi_sector <
2529 sh->dev[i].sector + STRIPE_SECTORS) {
2530 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
2531 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2532 if (!raid5_dec_bi_active_stripes(bi)) {
2533 md_write_end(conf->mddev);
2534 bi->bi_next = *return_bi;
2535 *return_bi = bi;
2536 }
2537 bi = bi2;
2538 }
2539
2540 /* fail any reads if this device is non-operational and
2541 * the data has not reached the cache yet.
2542 */
2543 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
2544 (!test_bit(R5_Insync, &sh->dev[i].flags) ||
2545 test_bit(R5_ReadError, &sh->dev[i].flags))) {
2546 spin_lock_irq(&sh->stripe_lock);
2547 bi = sh->dev[i].toread;
2548 sh->dev[i].toread = NULL;
2549 spin_unlock_irq(&sh->stripe_lock);
2550 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
2551 wake_up(&conf->wait_for_overlap);
2552 while (bi && bi->bi_sector <
2553 sh->dev[i].sector + STRIPE_SECTORS) {
2554 struct bio *nextbi =
2555 r5_next_bio(bi, sh->dev[i].sector);
2556 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2557 if (!raid5_dec_bi_active_stripes(bi)) {
2558 bi->bi_next = *return_bi;
2559 *return_bi = bi;
2560 }
2561 bi = nextbi;
2562 }
2563 }
2564 if (bitmap_end)
2565 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
2566 STRIPE_SECTORS, 0, 0);
2567 /* If we were in the middle of a write the parity block might
2568 * still be locked - so just clear all R5_LOCKED flags
2569 */
2570 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2571 }
2572
2573 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
2574 if (atomic_dec_and_test(&conf->pending_full_writes))
2575 md_wakeup_thread(conf->mddev->thread);
2576 }
2577
2578 static void
2579 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
2580 struct stripe_head_state *s)
2581 {
2582 int abort = 0;
2583 int i;
2584
2585 clear_bit(STRIPE_SYNCING, &sh->state);
2586 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
2587 wake_up(&conf->wait_for_overlap);
2588 s->syncing = 0;
2589 s->replacing = 0;
2590 /* There is nothing more to do for sync/check/repair.
2591 * Don't even need to abort as that is handled elsewhere
2592 * if needed, and not always wanted e.g. if there is a known
2593 * bad block here.
2594 * For recover/replace we need to record a bad block on all
2595 * non-sync devices, or abort the recovery
2596 */
2597 if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
2598 /* During recovery devices cannot be removed, so
2599 * locking and refcounting of rdevs is not needed
2600 */
2601 for (i = 0; i < conf->raid_disks; i++) {
2602 struct md_rdev *rdev = conf->disks[i].rdev;
2603 if (rdev
2604 && !test_bit(Faulty, &rdev->flags)
2605 && !test_bit(In_sync, &rdev->flags)
2606 && !rdev_set_badblocks(rdev, sh->sector,
2607 STRIPE_SECTORS, 0))
2608 abort = 1;
2609 rdev = conf->disks[i].replacement;
2610 if (rdev
2611 && !test_bit(Faulty, &rdev->flags)
2612 && !test_bit(In_sync, &rdev->flags)
2613 && !rdev_set_badblocks(rdev, sh->sector,
2614 STRIPE_SECTORS, 0))
2615 abort = 1;
2616 }
2617 if (abort)
2618 conf->recovery_disabled =
2619 conf->mddev->recovery_disabled;
2620 }
2621 md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
2622 }
2623
2624 static int want_replace(struct stripe_head *sh, int disk_idx)
2625 {
2626 struct md_rdev *rdev;
2627 int rv = 0;
2628 /* Doing recovery so rcu locking not required */
2629 rdev = sh->raid_conf->disks[disk_idx].replacement;
2630 if (rdev
2631 && !test_bit(Faulty, &rdev->flags)
2632 && !test_bit(In_sync, &rdev->flags)
2633 && (rdev->recovery_offset <= sh->sector
2634 || rdev->mddev->recovery_cp <= sh->sector))
2635 rv = 1;
2636
2637 return rv;
2638 }
2639
2640 /* fetch_block - checks the given member device to see if its data needs
2641 * to be read or computed to satisfy a request.
2642 *
2643 * Returns 1 when no more member devices need to be checked, otherwise returns
2644 * 0 to tell the loop in handle_stripe_fill to continue
2645 */
2646 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
2647 int disk_idx, int disks)
2648 {
2649 struct r5dev *dev = &sh->dev[disk_idx];
2650 struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
2651 &sh->dev[s->failed_num[1]] };
2652
2653 /* is the data in this block needed, and can we get it? */
2654 if (!test_bit(R5_LOCKED, &dev->flags) &&
2655 !test_bit(R5_UPTODATE, &dev->flags) &&
2656 (dev->toread ||
2657 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
2658 s->syncing || s->expanding ||
2659 (s->replacing && want_replace(sh, disk_idx)) ||
2660 (s->failed >= 1 && fdev[0]->toread) ||
2661 (s->failed >= 2 && fdev[1]->toread) ||
2662 (sh->raid_conf->level <= 5 && s->failed && fdev[0]->towrite &&
2663 !test_bit(R5_OVERWRITE, &fdev[0]->flags)) ||
2664 (sh->raid_conf->level == 6 && s->failed && s->to_write))) {
2665 /* we would like to get this block, possibly by computing it,
2666 * otherwise read it if the backing disk is insync
2667 */
2668 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
2669 BUG_ON(test_bit(R5_Wantread, &dev->flags));
2670 if ((s->uptodate == disks - 1) &&
2671 (s->failed && (disk_idx == s->failed_num[0] ||
2672 disk_idx == s->failed_num[1]))) {
2673 /* have disk failed, and we're requested to fetch it;
2674 * do compute it
2675 */
2676 pr_debug("Computing stripe %llu block %d\n",
2677 (unsigned long long)sh->sector, disk_idx);
2678 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2679 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
2680 set_bit(R5_Wantcompute, &dev->flags);
2681 sh->ops.target = disk_idx;
2682 sh->ops.target2 = -1; /* no 2nd target */
2683 s->req_compute = 1;
2684 /* Careful: from this point on 'uptodate' is in the eye
2685 * of raid_run_ops which services 'compute' operations
2686 * before writes. R5_Wantcompute flags a block that will
2687 * be R5_UPTODATE by the time it is needed for a
2688 * subsequent operation.
2689 */
2690 s->uptodate++;
2691 return 1;
2692 } else if (s->uptodate == disks-2 && s->failed >= 2) {
2693 /* Computing 2-failure is *very* expensive; only
2694 * do it if failed >= 2
2695 */
2696 int other;
2697 for (other = disks; other--; ) {
2698 if (other == disk_idx)
2699 continue;
2700 if (!test_bit(R5_UPTODATE,
2701 &sh->dev[other].flags))
2702 break;
2703 }
2704 BUG_ON(other < 0);
2705 pr_debug("Computing stripe %llu blocks %d,%d\n",
2706 (unsigned long long)sh->sector,
2707 disk_idx, other);
2708 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2709 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
2710 set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
2711 set_bit(R5_Wantcompute, &sh->dev[other].flags);
2712 sh->ops.target = disk_idx;
2713 sh->ops.target2 = other;
2714 s->uptodate += 2;
2715 s->req_compute = 1;
2716 return 1;
2717 } else if (test_bit(R5_Insync, &dev->flags)) {
2718 set_bit(R5_LOCKED, &dev->flags);
2719 set_bit(R5_Wantread, &dev->flags);
2720 s->locked++;
2721 pr_debug("Reading block %d (sync=%d)\n",
2722 disk_idx, s->syncing);
2723 }
2724 }
2725
2726 return 0;
2727 }
2728
2729 /**
2730 * handle_stripe_fill - read or compute data to satisfy pending requests.
2731 */
2732 static void handle_stripe_fill(struct stripe_head *sh,
2733 struct stripe_head_state *s,
2734 int disks)
2735 {
2736 int i;
2737
2738 /* look for blocks to read/compute, skip this if a compute
2739 * is already in flight, or if the stripe contents are in the
2740 * midst of changing due to a write
2741 */
2742 if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
2743 !sh->reconstruct_state)
2744 for (i = disks; i--; )
2745 if (fetch_block(sh, s, i, disks))
2746 break;
2747 set_bit(STRIPE_HANDLE, &sh->state);
2748 }
2749
2750
2751 /* handle_stripe_clean_event
2752 * any written block on an uptodate or failed drive can be returned.
2753 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
2754 * never LOCKED, so we don't need to test 'failed' directly.
2755 */
2756 static void handle_stripe_clean_event(struct r5conf *conf,
2757 struct stripe_head *sh, int disks, struct bio **return_bi)
2758 {
2759 int i;
2760 struct r5dev *dev;
2761 int discard_pending = 0;
2762
2763 for (i = disks; i--; )
2764 if (sh->dev[i].written) {
2765 dev = &sh->dev[i];
2766 if (!test_bit(R5_LOCKED, &dev->flags) &&
2767 (test_bit(R5_UPTODATE, &dev->flags) ||
2768 test_bit(R5_Discard, &dev->flags))) {
2769 /* We can return any write requests */
2770 struct bio *wbi, *wbi2;
2771 pr_debug("Return write for disc %d\n", i);
2772 if (test_and_clear_bit(R5_Discard, &dev->flags))
2773 clear_bit(R5_UPTODATE, &dev->flags);
2774 wbi = dev->written;
2775 dev->written = NULL;
2776 while (wbi && wbi->bi_sector <
2777 dev->sector + STRIPE_SECTORS) {
2778 wbi2 = r5_next_bio(wbi, dev->sector);
2779 if (!raid5_dec_bi_active_stripes(wbi)) {
2780 md_write_end(conf->mddev);
2781 wbi->bi_next = *return_bi;
2782 *return_bi = wbi;
2783 }
2784 wbi = wbi2;
2785 }
2786 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
2787 STRIPE_SECTORS,
2788 !test_bit(STRIPE_DEGRADED, &sh->state),
2789 0);
2790 } else if (test_bit(R5_Discard, &dev->flags))
2791 discard_pending = 1;
2792 }
2793 if (!discard_pending &&
2794 test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
2795 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
2796 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
2797 if (sh->qd_idx >= 0) {
2798 clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
2799 clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
2800 }
2801 /* now that discard is done we can proceed with any sync */
2802 clear_bit(STRIPE_DISCARD, &sh->state);
2803 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
2804 set_bit(STRIPE_HANDLE, &sh->state);
2805
2806 }
2807
2808 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
2809 if (atomic_dec_and_test(&conf->pending_full_writes))
2810 md_wakeup_thread(conf->mddev->thread);
2811 }
2812
2813 static void handle_stripe_dirtying(struct r5conf *conf,
2814 struct stripe_head *sh,
2815 struct stripe_head_state *s,
2816 int disks)
2817 {
2818 int rmw = 0, rcw = 0, i;
2819 sector_t recovery_cp = conf->mddev->recovery_cp;
2820
2821 /* RAID6 requires 'rcw' in current implementation.
2822 * Otherwise, check whether resync is now happening or should start.
2823 * If yes, then the array is dirty (after unclean shutdown or
2824 * initial creation), so parity in some stripes might be inconsistent.
2825 * In this case, we need to always do reconstruct-write, to ensure
2826 * that in case of drive failure or read-error correction, we
2827 * generate correct data from the parity.
2828 */
2829 if (conf->max_degraded == 2 ||
2830 (recovery_cp < MaxSector && sh->sector >= recovery_cp)) {
2831 /* Calculate the real rcw later - for now make it
2832 * look like rcw is cheaper
2833 */
2834 rcw = 1; rmw = 2;
2835 pr_debug("force RCW max_degraded=%u, recovery_cp=%llu sh->sector=%llu\n",
2836 conf->max_degraded, (unsigned long long)recovery_cp,
2837 (unsigned long long)sh->sector);
2838 } else for (i = disks; i--; ) {
2839 /* would I have to read this buffer for read_modify_write */
2840 struct r5dev *dev = &sh->dev[i];
2841 if ((dev->towrite || i == sh->pd_idx) &&
2842 !test_bit(R5_LOCKED, &dev->flags) &&
2843 !(test_bit(R5_UPTODATE, &dev->flags) ||
2844 test_bit(R5_Wantcompute, &dev->flags))) {
2845 if (test_bit(R5_Insync, &dev->flags))
2846 rmw++;
2847 else
2848 rmw += 2*disks; /* cannot read it */
2849 }
2850 /* Would I have to read this buffer for reconstruct_write */
2851 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
2852 !test_bit(R5_LOCKED, &dev->flags) &&
2853 !(test_bit(R5_UPTODATE, &dev->flags) ||
2854 test_bit(R5_Wantcompute, &dev->flags))) {
2855 if (test_bit(R5_Insync, &dev->flags)) rcw++;
2856 else
2857 rcw += 2*disks;
2858 }
2859 }
2860 pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2861 (unsigned long long)sh->sector, rmw, rcw);
2862 set_bit(STRIPE_HANDLE, &sh->state);
2863 if (rmw < rcw && rmw > 0) {
2864 /* prefer read-modify-write, but need to get some data */
2865 if (conf->mddev->queue)
2866 blk_add_trace_msg(conf->mddev->queue,
2867 "raid5 rmw %llu %d",
2868 (unsigned long long)sh->sector, rmw);
2869 for (i = disks; i--; ) {
2870 struct r5dev *dev = &sh->dev[i];
2871 if ((dev->towrite || i == sh->pd_idx) &&
2872 !test_bit(R5_LOCKED, &dev->flags) &&
2873 !(test_bit(R5_UPTODATE, &dev->flags) ||
2874 test_bit(R5_Wantcompute, &dev->flags)) &&
2875 test_bit(R5_Insync, &dev->flags)) {
2876 if (
2877 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2878 pr_debug("Read_old block "
2879 "%d for r-m-w\n", i);
2880 set_bit(R5_LOCKED, &dev->flags);
2881 set_bit(R5_Wantread, &dev->flags);
2882 s->locked++;
2883 } else {
2884 set_bit(STRIPE_DELAYED, &sh->state);
2885 set_bit(STRIPE_HANDLE, &sh->state);
2886 }
2887 }
2888 }
2889 }
2890 if (rcw <= rmw && rcw > 0) {
2891 /* want reconstruct write, but need to get some data */
2892 int qread =0;
2893 rcw = 0;
2894 for (i = disks; i--; ) {
2895 struct r5dev *dev = &sh->dev[i];
2896 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2897 i != sh->pd_idx && i != sh->qd_idx &&
2898 !test_bit(R5_LOCKED, &dev->flags) &&
2899 !(test_bit(R5_UPTODATE, &dev->flags) ||
2900 test_bit(R5_Wantcompute, &dev->flags))) {
2901 rcw++;
2902 if (!test_bit(R5_Insync, &dev->flags))
2903 continue; /* it's a failed drive */
2904 if (
2905 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2906 pr_debug("Read_old block "
2907 "%d for Reconstruct\n", i);
2908 set_bit(R5_LOCKED, &dev->flags);
2909 set_bit(R5_Wantread, &dev->flags);
2910 s->locked++;
2911 qread++;
2912 } else {
2913 set_bit(STRIPE_DELAYED, &sh->state);
2914 set_bit(STRIPE_HANDLE, &sh->state);
2915 }
2916 }
2917 }
2918 if (rcw && conf->mddev->queue)
2919 blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
2920 (unsigned long long)sh->sector,
2921 rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
2922 }
2923 /* now if nothing is locked, and if we have enough data,
2924 * we can start a write request
2925 */
2926 /* since handle_stripe can be called at any time we need to handle the
2927 * case where a compute block operation has been submitted and then a
2928 * subsequent call wants to start a write request. raid_run_ops only
2929 * handles the case where compute block and reconstruct are requested
2930 * simultaneously. If this is not the case then new writes need to be
2931 * held off until the compute completes.
2932 */
2933 if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
2934 (s->locked == 0 && (rcw == 0 || rmw == 0) &&
2935 !test_bit(STRIPE_BIT_DELAY, &sh->state)))
2936 schedule_reconstruction(sh, s, rcw == 0, 0);
2937 }
2938
2939 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
2940 struct stripe_head_state *s, int disks)
2941 {
2942 struct r5dev *dev = NULL;
2943
2944 set_bit(STRIPE_HANDLE, &sh->state);
2945
2946 switch (sh->check_state) {
2947 case check_state_idle:
2948 /* start a new check operation if there are no failures */
2949 if (s->failed == 0) {
2950 BUG_ON(s->uptodate != disks);
2951 sh->check_state = check_state_run;
2952 set_bit(STRIPE_OP_CHECK, &s->ops_request);
2953 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
2954 s->uptodate--;
2955 break;
2956 }
2957 dev = &sh->dev[s->failed_num[0]];
2958 /* fall through */
2959 case check_state_compute_result:
2960 sh->check_state = check_state_idle;
2961 if (!dev)
2962 dev = &sh->dev[sh->pd_idx];
2963
2964 /* check that a write has not made the stripe insync */
2965 if (test_bit(STRIPE_INSYNC, &sh->state))
2966 break;
2967
2968 /* either failed parity check, or recovery is happening */
2969 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
2970 BUG_ON(s->uptodate != disks);
2971
2972 set_bit(R5_LOCKED, &dev->flags);
2973 s->locked++;
2974 set_bit(R5_Wantwrite, &dev->flags);
2975
2976 clear_bit(STRIPE_DEGRADED, &sh->state);
2977 set_bit(STRIPE_INSYNC, &sh->state);
2978 break;
2979 case check_state_run:
2980 break; /* we will be called again upon completion */
2981 case check_state_check_result:
2982 sh->check_state = check_state_idle;
2983
2984 /* if a failure occurred during the check operation, leave
2985 * STRIPE_INSYNC not set and let the stripe be handled again
2986 */
2987 if (s->failed)
2988 break;
2989
2990 /* handle a successful check operation, if parity is correct
2991 * we are done. Otherwise update the mismatch count and repair
2992 * parity if !MD_RECOVERY_CHECK
2993 */
2994 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
2995 /* parity is correct (on disc,
2996 * not in buffer any more)
2997 */
2998 set_bit(STRIPE_INSYNC, &sh->state);
2999 else {
3000 atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
3001 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
3002 /* don't try to repair!! */
3003 set_bit(STRIPE_INSYNC, &sh->state);
3004 else {
3005 sh->check_state = check_state_compute_run;
3006 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3007 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3008 set_bit(R5_Wantcompute,
3009 &sh->dev[sh->pd_idx].flags);
3010 sh->ops.target = sh->pd_idx;
3011 sh->ops.target2 = -1;
3012 s->uptodate++;
3013 }
3014 }
3015 break;
3016 case check_state_compute_run:
3017 break;
3018 default:
3019 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
3020 __func__, sh->check_state,
3021 (unsigned long long) sh->sector);
3022 BUG();
3023 }
3024 }
3025
3026
3027 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
3028 struct stripe_head_state *s,
3029 int disks)
3030 {
3031 int pd_idx = sh->pd_idx;
3032 int qd_idx = sh->qd_idx;
3033 struct r5dev *dev;
3034
3035 set_bit(STRIPE_HANDLE, &sh->state);
3036
3037 BUG_ON(s->failed > 2);
3038
3039 /* Want to check and possibly repair P and Q.
3040 * However there could be one 'failed' device, in which
3041 * case we can only check one of them, possibly using the
3042 * other to generate missing data
3043 */
3044
3045 switch (sh->check_state) {
3046 case check_state_idle:
3047 /* start a new check operation if there are < 2 failures */
3048 if (s->failed == s->q_failed) {
3049 /* The only possible failed device holds Q, so it
3050 * makes sense to check P (If anything else were failed,
3051 * we would have used P to recreate it).
3052 */
3053 sh->check_state = check_state_run;
3054 }
3055 if (!s->q_failed && s->failed < 2) {
3056 /* Q is not failed, and we didn't use it to generate
3057 * anything, so it makes sense to check it
3058 */
3059 if (sh->check_state == check_state_run)
3060 sh->check_state = check_state_run_pq;
3061 else
3062 sh->check_state = check_state_run_q;
3063 }
3064
3065 /* discard potentially stale zero_sum_result */
3066 sh->ops.zero_sum_result = 0;
3067
3068 if (sh->check_state == check_state_run) {
3069 /* async_xor_zero_sum destroys the contents of P */
3070 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3071 s->uptodate--;
3072 }
3073 if (sh->check_state >= check_state_run &&
3074 sh->check_state <= check_state_run_pq) {
3075 /* async_syndrome_zero_sum preserves P and Q, so
3076 * no need to mark them !uptodate here
3077 */
3078 set_bit(STRIPE_OP_CHECK, &s->ops_request);
3079 break;
3080 }
3081
3082 /* we have 2-disk failure */
3083 BUG_ON(s->failed != 2);
3084 /* fall through */
3085 case check_state_compute_result:
3086 sh->check_state = check_state_idle;
3087
3088 /* check that a write has not made the stripe insync */
3089 if (test_bit(STRIPE_INSYNC, &sh->state))
3090 break;
3091
3092 /* now write out any block on a failed drive,
3093 * or P or Q if they were recomputed
3094 */
3095 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
3096 if (s->failed == 2) {
3097 dev = &sh->dev[s->failed_num[1]];
3098 s->locked++;
3099 set_bit(R5_LOCKED, &dev->flags);
3100 set_bit(R5_Wantwrite, &dev->flags);
3101 }
3102 if (s->failed >= 1) {
3103 dev = &sh->dev[s->failed_num[0]];
3104 s->locked++;
3105 set_bit(R5_LOCKED, &dev->flags);
3106 set_bit(R5_Wantwrite, &dev->flags);
3107 }
3108 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
3109 dev = &sh->dev[pd_idx];
3110 s->locked++;
3111 set_bit(R5_LOCKED, &dev->flags);
3112 set_bit(R5_Wantwrite, &dev->flags);
3113 }
3114 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
3115 dev = &sh->dev[qd_idx];
3116 s->locked++;
3117 set_bit(R5_LOCKED, &dev->flags);
3118 set_bit(R5_Wantwrite, &dev->flags);
3119 }
3120 clear_bit(STRIPE_DEGRADED, &sh->state);
3121
3122 set_bit(STRIPE_INSYNC, &sh->state);
3123 break;
3124 case check_state_run:
3125 case check_state_run_q:
3126 case check_state_run_pq:
3127 break; /* we will be called again upon completion */
3128 case check_state_check_result:
3129 sh->check_state = check_state_idle;
3130
3131 /* handle a successful check operation, if parity is correct
3132 * we are done. Otherwise update the mismatch count and repair
3133 * parity if !MD_RECOVERY_CHECK
3134 */
3135 if (sh->ops.zero_sum_result == 0) {
3136 /* both parities are correct */
3137 if (!s->failed)
3138 set_bit(STRIPE_INSYNC, &sh->state);
3139 else {
3140 /* in contrast to the raid5 case we can validate
3141 * parity, but still have a failure to write
3142 * back
3143 */
3144 sh->check_state = check_state_compute_result;
3145 /* Returning at this point means that we may go
3146 * off and bring p and/or q uptodate again so
3147 * we make sure to check zero_sum_result again
3148 * to verify if p or q need writeback
3149 */
3150 }
3151 } else {
3152 atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
3153 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
3154 /* don't try to repair!! */
3155 set_bit(STRIPE_INSYNC, &sh->state);
3156 else {
3157 int *target = &sh->ops.target;
3158
3159 sh->ops.target = -1;
3160 sh->ops.target2 = -1;
3161 sh->check_state = check_state_compute_run;
3162 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3163 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3164 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
3165 set_bit(R5_Wantcompute,
3166 &sh->dev[pd_idx].flags);
3167 *target = pd_idx;
3168 target = &sh->ops.target2;
3169 s->uptodate++;
3170 }
3171 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
3172 set_bit(R5_Wantcompute,
3173 &sh->dev[qd_idx].flags);
3174 *target = qd_idx;
3175 s->uptodate++;
3176 }
3177 }
3178 }
3179 break;
3180 case check_state_compute_run:
3181 break;
3182 default:
3183 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
3184 __func__, sh->check_state,
3185 (unsigned long long) sh->sector);
3186 BUG();
3187 }
3188 }
3189
3190 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
3191 {
3192 int i;
3193
3194 /* We have read all the blocks in this stripe and now we need to
3195 * copy some of them into a target stripe for expand.
3196 */
3197 struct dma_async_tx_descriptor *tx = NULL;
3198 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
3199 for (i = 0; i < sh->disks; i++)
3200 if (i != sh->pd_idx && i != sh->qd_idx) {
3201 int dd_idx, j;
3202 struct stripe_head *sh2;
3203 struct async_submit_ctl submit;
3204
3205 sector_t bn = compute_blocknr(sh, i, 1);
3206 sector_t s = raid5_compute_sector(conf, bn, 0,
3207 &dd_idx, NULL);
3208 sh2 = get_active_stripe(conf, s, 0, 1, 1);
3209 if (sh2 == NULL)
3210 /* so far only the early blocks of this stripe
3211 * have been requested. When later blocks
3212 * get requested, we will try again
3213 */
3214 continue;
3215 if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
3216 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
3217 /* must have already done this block */
3218 release_stripe(sh2);
3219 continue;
3220 }
3221
3222 /* place all the copies on one channel */
3223 init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
3224 tx = async_memcpy(sh2->dev[dd_idx].page,
3225 sh->dev[i].page, 0, 0, STRIPE_SIZE,
3226 &submit);
3227
3228 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
3229 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
3230 for (j = 0; j < conf->raid_disks; j++)
3231 if (j != sh2->pd_idx &&
3232 j != sh2->qd_idx &&
3233 !test_bit(R5_Expanded, &sh2->dev[j].flags))
3234 break;
3235 if (j == conf->raid_disks) {
3236 set_bit(STRIPE_EXPAND_READY, &sh2->state);
3237 set_bit(STRIPE_HANDLE, &sh2->state);
3238 }
3239 release_stripe(sh2);
3240
3241 }
3242 /* done submitting copies, wait for them to complete */
3243 async_tx_quiesce(&tx);
3244 }
3245
3246 /*
3247 * handle_stripe - do things to a stripe.
3248 *
3249 * We lock the stripe by setting STRIPE_ACTIVE and then examine the
3250 * state of various bits to see what needs to be done.
3251 * Possible results:
3252 * return some read requests which now have data
3253 * return some write requests which are safely on storage
3254 * schedule a read on some buffers
3255 * schedule a write of some buffers
3256 * return confirmation of parity correctness
3257 *
3258 */
3259
3260 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
3261 {
3262 struct r5conf *conf = sh->raid_conf;
3263 int disks = sh->disks;
3264 struct r5dev *dev;
3265 int i;
3266 int do_recovery = 0;
3267
3268 memset(s, 0, sizeof(*s));
3269
3270 s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
3271 s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
3272 s->failed_num[0] = -1;
3273 s->failed_num[1] = -1;
3274
3275 /* Now to look around and see what can be done */
3276 rcu_read_lock();
3277 for (i=disks; i--; ) {
3278 struct md_rdev *rdev;
3279 sector_t first_bad;
3280 int bad_sectors;
3281 int is_bad = 0;
3282
3283 dev = &sh->dev[i];
3284
3285 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3286 i, dev->flags,
3287 dev->toread, dev->towrite, dev->written);
3288 /* maybe we can reply to a read
3289 *
3290 * new wantfill requests are only permitted while
3291 * ops_complete_biofill is guaranteed to be inactive
3292 */
3293 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
3294 !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
3295 set_bit(R5_Wantfill, &dev->flags);
3296
3297 /* now count some things */
3298 if (test_bit(R5_LOCKED, &dev->flags))
3299 s->locked++;
3300 if (test_bit(R5_UPTODATE, &dev->flags))
3301 s->uptodate++;
3302 if (test_bit(R5_Wantcompute, &dev->flags)) {
3303 s->compute++;
3304 BUG_ON(s->compute > 2);
3305 }
3306
3307 if (test_bit(R5_Wantfill, &dev->flags))
3308 s->to_fill++;
3309 else if (dev->toread)
3310 s->to_read++;
3311 if (dev->towrite) {
3312 s->to_write++;
3313 if (!test_bit(R5_OVERWRITE, &dev->flags))
3314 s->non_overwrite++;
3315 }
3316 if (dev->written)
3317 s->written++;
3318 /* Prefer to use the replacement for reads, but only
3319 * if it is recovered enough and has no bad blocks.
3320 */
3321 rdev = rcu_dereference(conf->disks[i].replacement);
3322 if (rdev && !test_bit(Faulty, &rdev->flags) &&
3323 rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
3324 !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
3325 &first_bad, &bad_sectors))
3326 set_bit(R5_ReadRepl, &dev->flags);
3327 else {
3328 if (rdev)
3329 set_bit(R5_NeedReplace, &dev->flags);
3330 rdev = rcu_dereference(conf->disks[i].rdev);
3331 clear_bit(R5_ReadRepl, &dev->flags);
3332 }
3333 if (rdev && test_bit(Faulty, &rdev->flags))
3334 rdev = NULL;
3335 if (rdev) {
3336 is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
3337 &first_bad, &bad_sectors);
3338 if (s->blocked_rdev == NULL
3339 && (test_bit(Blocked, &rdev->flags)
3340 || is_bad < 0)) {
3341 if (is_bad < 0)
3342 set_bit(BlockedBadBlocks,
3343 &rdev->flags);
3344 s->blocked_rdev = rdev;
3345 atomic_inc(&rdev->nr_pending);
3346 }
3347 }
3348 clear_bit(R5_Insync, &dev->flags);
3349 if (!rdev)
3350 /* Not in-sync */;
3351 else if (is_bad) {
3352 /* also not in-sync */
3353 if (!test_bit(WriteErrorSeen, &rdev->flags) &&
3354 test_bit(R5_UPTODATE, &dev->flags)) {
3355 /* treat as in-sync, but with a read error
3356 * which we can now try to correct
3357 */
3358 set_bit(R5_Insync, &dev->flags);
3359 set_bit(R5_ReadError, &dev->flags);
3360 }
3361 } else if (test_bit(In_sync, &rdev->flags))
3362 set_bit(R5_Insync, &dev->flags);
3363 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
3364 /* in sync if before recovery_offset */
3365 set_bit(R5_Insync, &dev->flags);
3366 else if (test_bit(R5_UPTODATE, &dev->flags) &&
3367 test_bit(R5_Expanded, &dev->flags))
3368 /* If we've reshaped into here, we assume it is Insync.
3369 * We will shortly update recovery_offset to make
3370 * it official.
3371 */
3372 set_bit(R5_Insync, &dev->flags);
3373
3374 if (rdev && test_bit(R5_WriteError, &dev->flags)) {
3375 /* This flag does not apply to '.replacement'
3376 * only to .rdev, so make sure to check that*/
3377 struct md_rdev *rdev2 = rcu_dereference(
3378 conf->disks[i].rdev);
3379 if (rdev2 == rdev)
3380 clear_bit(R5_Insync, &dev->flags);
3381 if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
3382 s->handle_bad_blocks = 1;
3383 atomic_inc(&rdev2->nr_pending);
3384 } else
3385 clear_bit(R5_WriteError, &dev->flags);
3386 }
3387 if (rdev && test_bit(R5_MadeGood, &dev->flags)) {
3388 /* This flag does not apply to '.replacement'
3389 * only to .rdev, so make sure to check that*/
3390 struct md_rdev *rdev2 = rcu_dereference(
3391 conf->disks[i].rdev);
3392 if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
3393 s->handle_bad_blocks = 1;
3394 atomic_inc(&rdev2->nr_pending);
3395 } else
3396 clear_bit(R5_MadeGood, &dev->flags);
3397 }
3398 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
3399 struct md_rdev *rdev2 = rcu_dereference(
3400 conf->disks[i].replacement);
3401 if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
3402 s->handle_bad_blocks = 1;
3403 atomic_inc(&rdev2->nr_pending);
3404 } else
3405 clear_bit(R5_MadeGoodRepl, &dev->flags);
3406 }
3407 if (!test_bit(R5_Insync, &dev->flags)) {
3408 /* The ReadError flag will just be confusing now */
3409 clear_bit(R5_ReadError, &dev->flags);
3410 clear_bit(R5_ReWrite, &dev->flags);
3411 }
3412 if (test_bit(R5_ReadError, &dev->flags))
3413 clear_bit(R5_Insync, &dev->flags);
3414 if (!test_bit(R5_Insync, &dev->flags)) {
3415 if (s->failed < 2)
3416 s->failed_num[s->failed] = i;
3417 s->failed++;
3418 if (rdev && !test_bit(Faulty, &rdev->flags))
3419 do_recovery = 1;
3420 }
3421 }
3422 if (test_bit(STRIPE_SYNCING, &sh->state)) {
3423 /* If there is a failed device being replaced,
3424 * we must be recovering.
3425 * else if we are after recovery_cp, we must be syncing
3426 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
3427 * else we can only be replacing
3428 * sync and recovery both need to read all devices, and so
3429 * use the same flag.
3430 */
3431 if (do_recovery ||
3432 sh->sector >= conf->mddev->recovery_cp ||
3433 test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
3434 s->syncing = 1;
3435 else
3436 s->replacing = 1;
3437 }
3438 rcu_read_unlock();
3439 }
3440
3441 static void handle_stripe(struct stripe_head *sh)
3442 {
3443 struct stripe_head_state s;
3444 struct r5conf *conf = sh->raid_conf;
3445 int i;
3446 int prexor;
3447 int disks = sh->disks;
3448 struct r5dev *pdev, *qdev;
3449
3450 clear_bit(STRIPE_HANDLE, &sh->state);
3451 if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
3452 /* already being handled, ensure it gets handled
3453 * again when current action finishes */
3454 set_bit(STRIPE_HANDLE, &sh->state);
3455 return;
3456 }
3457
3458 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
3459 spin_lock(&sh->stripe_lock);
3460 /* Cannot process 'sync' concurrently with 'discard' */
3461 if (!test_bit(STRIPE_DISCARD, &sh->state) &&
3462 test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
3463 set_bit(STRIPE_SYNCING, &sh->state);
3464 clear_bit(STRIPE_INSYNC, &sh->state);
3465 }
3466 spin_unlock(&sh->stripe_lock);
3467 }
3468 clear_bit(STRIPE_DELAYED, &sh->state);
3469
3470 pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
3471 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
3472 (unsigned long long)sh->sector, sh->state,
3473 atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
3474 sh->check_state, sh->reconstruct_state);
3475
3476 analyse_stripe(sh, &s);
3477
3478 if (s.handle_bad_blocks) {
3479 set_bit(STRIPE_HANDLE, &sh->state);
3480 goto finish;
3481 }
3482
3483 if (unlikely(s.blocked_rdev)) {
3484 if (s.syncing || s.expanding || s.expanded ||
3485 s.replacing || s.to_write || s.written) {
3486 set_bit(STRIPE_HANDLE, &sh->state);
3487 goto finish;
3488 }
3489 /* There is nothing for the blocked_rdev to block */
3490 rdev_dec_pending(s.blocked_rdev, conf->mddev);
3491 s.blocked_rdev = NULL;
3492 }
3493
3494 if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
3495 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
3496 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
3497 }
3498
3499 pr_debug("locked=%d uptodate=%d to_read=%d"
3500 " to_write=%d failed=%d failed_num=%d,%d\n",
3501 s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
3502 s.failed_num[0], s.failed_num[1]);
3503 /* check if the array has lost more than max_degraded devices and,
3504 * if so, some requests might need to be failed.
3505 */
3506 if (s.failed > conf->max_degraded) {
3507 sh->check_state = 0;
3508 sh->reconstruct_state = 0;
3509 if (s.to_read+s.to_write+s.written)
3510 handle_failed_stripe(conf, sh, &s, disks, &s.return_bi);
3511 if (s.syncing + s.replacing)
3512 handle_failed_sync(conf, sh, &s);
3513 }
3514
3515 /* Now we check to see if any write operations have recently
3516 * completed
3517 */
3518 prexor = 0;
3519 if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
3520 prexor = 1;
3521 if (sh->reconstruct_state == reconstruct_state_drain_result ||
3522 sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
3523 sh->reconstruct_state = reconstruct_state_idle;
3524
3525 /* All the 'written' buffers and the parity block are ready to
3526 * be written back to disk
3527 */
3528 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
3529 !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
3530 BUG_ON(sh->qd_idx >= 0 &&
3531 !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
3532 !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
3533 for (i = disks; i--; ) {
3534 struct r5dev *dev = &sh->dev[i];
3535 if (test_bit(R5_LOCKED, &dev->flags) &&
3536 (i == sh->pd_idx || i == sh->qd_idx ||
3537 dev->written)) {
3538 pr_debug("Writing block %d\n", i);
3539 set_bit(R5_Wantwrite, &dev->flags);
3540 if (prexor)
3541 continue;
3542 if (!test_bit(R5_Insync, &dev->flags) ||
3543 ((i == sh->pd_idx || i == sh->qd_idx) &&
3544 s.failed == 0))
3545 set_bit(STRIPE_INSYNC, &sh->state);
3546 }
3547 }
3548 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3549 s.dec_preread_active = 1;
3550 }
3551
3552 /*
3553 * might be able to return some write requests if the parity blocks
3554 * are safe, or on a failed drive
3555 */
3556 pdev = &sh->dev[sh->pd_idx];
3557 s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
3558 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
3559 qdev = &sh->dev[sh->qd_idx];
3560 s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
3561 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
3562 || conf->level < 6;
3563
3564 if (s.written &&
3565 (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
3566 && !test_bit(R5_LOCKED, &pdev->flags)
3567 && (test_bit(R5_UPTODATE, &pdev->flags) ||
3568 test_bit(R5_Discard, &pdev->flags))))) &&
3569 (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
3570 && !test_bit(R5_LOCKED, &qdev->flags)
3571 && (test_bit(R5_UPTODATE, &qdev->flags) ||
3572 test_bit(R5_Discard, &qdev->flags))))))
3573 handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
3574
3575 /* Now we might consider reading some blocks, either to check/generate
3576 * parity, or to satisfy requests
3577 * or to load a block that is being partially written.
3578 */
3579 if (s.to_read || s.non_overwrite
3580 || (conf->level == 6 && s.to_write && s.failed)
3581 || (s.syncing && (s.uptodate + s.compute < disks))
3582 || s.replacing
3583 || s.expanding)
3584 handle_stripe_fill(sh, &s, disks);
3585
3586 /* Now to consider new write requests and what else, if anything
3587 * should be read. We do not handle new writes when:
3588 * 1/ A 'write' operation (copy+xor) is already in flight.
3589 * 2/ A 'check' operation is in flight, as it may clobber the parity
3590 * block.
3591 */
3592 if (s.to_write && !sh->reconstruct_state && !sh->check_state)
3593 handle_stripe_dirtying(conf, sh, &s, disks);
3594
3595 /* maybe we need to check and possibly fix the parity for this stripe
3596 * Any reads will already have been scheduled, so we just see if enough
3597 * data is available. The parity check is held off while parity
3598 * dependent operations are in flight.
3599 */
3600 if (sh->check_state ||
3601 (s.syncing && s.locked == 0 &&
3602 !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
3603 !test_bit(STRIPE_INSYNC, &sh->state))) {
3604 if (conf->level == 6)
3605 handle_parity_checks6(conf, sh, &s, disks);
3606 else
3607 handle_parity_checks5(conf, sh, &s, disks);
3608 }
3609
3610 if (s.replacing && s.locked == 0
3611 && !test_bit(STRIPE_INSYNC, &sh->state)) {
3612 /* Write out to replacement devices where possible */
3613 for (i = 0; i < conf->raid_disks; i++)
3614 if (test_bit(R5_UPTODATE, &sh->dev[i].flags) &&
3615 test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
3616 set_bit(R5_WantReplace, &sh->dev[i].flags);
3617 set_bit(R5_LOCKED, &sh->dev[i].flags);
3618 s.locked++;
3619 }
3620 set_bit(STRIPE_INSYNC, &sh->state);
3621 }
3622 if ((s.syncing || s.replacing) && s.locked == 0 &&
3623 test_bit(STRIPE_INSYNC, &sh->state)) {
3624 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
3625 clear_bit(STRIPE_SYNCING, &sh->state);
3626 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3627 wake_up(&conf->wait_for_overlap);
3628 }
3629
3630 /* If the failed drives are just a ReadError, then we might need
3631 * to progress the repair/check process
3632 */
3633 if (s.failed <= conf->max_degraded && !conf->mddev->ro)
3634 for (i = 0; i < s.failed; i++) {
3635 struct r5dev *dev = &sh->dev[s.failed_num[i]];
3636 if (test_bit(R5_ReadError, &dev->flags)
3637 && !test_bit(R5_LOCKED, &dev->flags)
3638 && test_bit(R5_UPTODATE, &dev->flags)
3639 ) {
3640 if (!test_bit(R5_ReWrite, &dev->flags)) {
3641 set_bit(R5_Wantwrite, &dev->flags);
3642 set_bit(R5_ReWrite, &dev->flags);
3643 set_bit(R5_LOCKED, &dev->flags);
3644 s.locked++;
3645 } else {
3646 /* let's read it back */
3647 set_bit(R5_Wantread, &dev->flags);
3648 set_bit(R5_LOCKED, &dev->flags);
3649 s.locked++;
3650 }
3651 }
3652 }
3653
3654
3655 /* Finish reconstruct operations initiated by the expansion process */
3656 if (sh->reconstruct_state == reconstruct_state_result) {
3657 struct stripe_head *sh_src
3658 = get_active_stripe(conf, sh->sector, 1, 1, 1);
3659 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
3660 /* sh cannot be written until sh_src has been read.
3661 * so arrange for sh to be delayed a little
3662 */
3663 set_bit(STRIPE_DELAYED, &sh->state);
3664 set_bit(STRIPE_HANDLE, &sh->state);
3665 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
3666 &sh_src->state))
3667 atomic_inc(&conf->preread_active_stripes);
3668 release_stripe(sh_src);
3669 goto finish;
3670 }
3671 if (sh_src)
3672 release_stripe(sh_src);
3673
3674 sh->reconstruct_state = reconstruct_state_idle;
3675 clear_bit(STRIPE_EXPANDING, &sh->state);
3676 for (i = conf->raid_disks; i--; ) {
3677 set_bit(R5_Wantwrite, &sh->dev[i].flags);
3678 set_bit(R5_LOCKED, &sh->dev[i].flags);
3679 s.locked++;
3680 }
3681 }
3682
3683 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
3684 !sh->reconstruct_state) {
3685 /* Need to write out all blocks after computing parity */
3686 sh->disks = conf->raid_disks;
3687 stripe_set_idx(sh->sector, conf, 0, sh);
3688 schedule_reconstruction(sh, &s, 1, 1);
3689 } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
3690 clear_bit(STRIPE_EXPAND_READY, &sh->state);
3691 atomic_dec(&conf->reshape_stripes);
3692 wake_up(&conf->wait_for_overlap);
3693 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
3694 }
3695
3696 if (s.expanding && s.locked == 0 &&
3697 !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
3698 handle_stripe_expansion(conf, sh);
3699
3700 finish:
3701 /* wait for this device to become unblocked */
3702 if (unlikely(s.blocked_rdev)) {
3703 if (conf->mddev->external)
3704 md_wait_for_blocked_rdev(s.blocked_rdev,
3705 conf->mddev);
3706 else
3707 /* Internal metadata will immediately
3708 * be written by raid5d, so we don't
3709 * need to wait here.
3710 */
3711 rdev_dec_pending(s.blocked_rdev,
3712 conf->mddev);
3713 }
3714
3715 if (s.handle_bad_blocks)
3716 for (i = disks; i--; ) {
3717 struct md_rdev *rdev;
3718 struct r5dev *dev = &sh->dev[i];
3719 if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
3720 /* We own a safe reference to the rdev */
3721 rdev = conf->disks[i].rdev;
3722 if (!rdev_set_badblocks(rdev, sh->sector,
3723 STRIPE_SECTORS, 0))
3724 md_error(conf->mddev, rdev);
3725 rdev_dec_pending(rdev, conf->mddev);
3726 }
3727 if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
3728 rdev = conf->disks[i].rdev;
3729 rdev_clear_badblocks(rdev, sh->sector,
3730 STRIPE_SECTORS, 0);
3731 rdev_dec_pending(rdev, conf->mddev);
3732 }
3733 if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
3734 rdev = conf->disks[i].replacement;
3735 if (!rdev)
3736 /* rdev have been moved down */
3737 rdev = conf->disks[i].rdev;
3738 rdev_clear_badblocks(rdev, sh->sector,
3739 STRIPE_SECTORS, 0);
3740 rdev_dec_pending(rdev, conf->mddev);
3741 }
3742 }
3743
3744 if (s.ops_request)
3745 raid_run_ops(sh, s.ops_request);
3746
3747 ops_run_io(sh, &s);
3748
3749 if (s.dec_preread_active) {
3750 /* We delay this until after ops_run_io so that if make_request
3751 * is waiting on a flush, it won't continue until the writes
3752 * have actually been submitted.
3753 */
3754 atomic_dec(&conf->preread_active_stripes);
3755 if (atomic_read(&conf->preread_active_stripes) <
3756 IO_THRESHOLD)
3757 md_wakeup_thread(conf->mddev->thread);
3758 }
3759
3760 return_io(s.return_bi);
3761
3762 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
3763 }
3764
3765 static void raid5_activate_delayed(struct r5conf *conf)
3766 {
3767 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
3768 while (!list_empty(&conf->delayed_list)) {
3769 struct list_head *l = conf->delayed_list.next;
3770 struct stripe_head *sh;
3771 sh = list_entry(l, struct stripe_head, lru);
3772 list_del_init(l);
3773 clear_bit(STRIPE_DELAYED, &sh->state);
3774 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3775 atomic_inc(&conf->preread_active_stripes);
3776 list_add_tail(&sh->lru, &conf->hold_list);
3777 }
3778 }
3779 }
3780
3781 static void activate_bit_delay(struct r5conf *conf)
3782 {
3783 /* device_lock is held */
3784 struct list_head head;
3785 list_add(&head, &conf->bitmap_list);
3786 list_del_init(&conf->bitmap_list);
3787 while (!list_empty(&head)) {
3788 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
3789 list_del_init(&sh->lru);
3790 atomic_inc(&sh->count);
3791 __release_stripe(conf, sh);
3792 }
3793 }
3794
3795 int md_raid5_congested(struct mddev *mddev, int bits)
3796 {
3797 struct r5conf *conf = mddev->private;
3798
3799 /* No difference between reads and writes. Just check
3800 * how busy the stripe_cache is
3801 */
3802
3803 if (conf->inactive_blocked)
3804 return 1;
3805 if (conf->quiesce)
3806 return 1;
3807 if (list_empty_careful(&conf->inactive_list))
3808 return 1;
3809
3810 return 0;
3811 }
3812 EXPORT_SYMBOL_GPL(md_raid5_congested);
3813
3814 static int raid5_congested(void *data, int bits)
3815 {
3816 struct mddev *mddev = data;
3817
3818 return mddev_congested(mddev, bits) ||
3819 md_raid5_congested(mddev, bits);
3820 }
3821
3822 /* We want read requests to align with chunks where possible,
3823 * but write requests don't need to.
3824 */
3825 static int raid5_mergeable_bvec(struct request_queue *q,
3826 struct bvec_merge_data *bvm,
3827 struct bio_vec *biovec)
3828 {
3829 struct mddev *mddev = q->queuedata;
3830 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3831 int max;
3832 unsigned int chunk_sectors = mddev->chunk_sectors;
3833 unsigned int bio_sectors = bvm->bi_size >> 9;
3834
3835 if ((bvm->bi_rw & 1) == WRITE)
3836 return biovec->bv_len; /* always allow writes to be mergeable */
3837
3838 if (mddev->new_chunk_sectors < mddev->chunk_sectors)
3839 chunk_sectors = mddev->new_chunk_sectors;
3840 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
3841 if (max < 0) max = 0;
3842 if (max <= biovec->bv_len && bio_sectors == 0)
3843 return biovec->bv_len;
3844 else
3845 return max;
3846 }
3847
3848
3849 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
3850 {
3851 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3852 unsigned int chunk_sectors = mddev->chunk_sectors;
3853 unsigned int bio_sectors = bio_sectors(bio);
3854
3855 if (mddev->new_chunk_sectors < mddev->chunk_sectors)
3856 chunk_sectors = mddev->new_chunk_sectors;
3857 return chunk_sectors >=
3858 ((sector & (chunk_sectors - 1)) + bio_sectors);
3859 }
3860
3861 /*
3862 * add bio to the retry LIFO ( in O(1) ... we are in interrupt )
3863 * later sampled by raid5d.
3864 */
3865 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
3866 {
3867 unsigned long flags;
3868
3869 spin_lock_irqsave(&conf->device_lock, flags);
3870
3871 bi->bi_next = conf->retry_read_aligned_list;
3872 conf->retry_read_aligned_list = bi;
3873
3874 spin_unlock_irqrestore(&conf->device_lock, flags);
3875 md_wakeup_thread(conf->mddev->thread);
3876 }
3877
3878
3879 static struct bio *remove_bio_from_retry(struct r5conf *conf)
3880 {
3881 struct bio *bi;
3882
3883 bi = conf->retry_read_aligned;
3884 if (bi) {
3885 conf->retry_read_aligned = NULL;
3886 return bi;
3887 }
3888 bi = conf->retry_read_aligned_list;
3889 if(bi) {
3890 conf->retry_read_aligned_list = bi->bi_next;
3891 bi->bi_next = NULL;
3892 /*
3893 * this sets the active strip count to 1 and the processed
3894 * strip count to zero (upper 8 bits)
3895 */
3896 raid5_set_bi_stripes(bi, 1); /* biased count of active stripes */
3897 }
3898
3899 return bi;
3900 }
3901
3902
3903 /*
3904 * The "raid5_align_endio" should check if the read succeeded and if it
3905 * did, call bio_endio on the original bio (having bio_put the new bio
3906 * first).
3907 * If the read failed..
3908 */
3909 static void raid5_align_endio(struct bio *bi, int error)
3910 {
3911 struct bio* raid_bi = bi->bi_private;
3912 struct mddev *mddev;
3913 struct r5conf *conf;
3914 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3915 struct md_rdev *rdev;
3916
3917 bio_put(bi);
3918
3919 rdev = (void*)raid_bi->bi_next;
3920 raid_bi->bi_next = NULL;
3921 mddev = rdev->mddev;
3922 conf = mddev->private;
3923
3924 rdev_dec_pending(rdev, conf->mddev);
3925
3926 if (!error && uptodate) {
3927 trace_block_bio_complete(bdev_get_queue(raid_bi->bi_bdev),
3928 raid_bi, 0);
3929 bio_endio(raid_bi, 0);
3930 if (atomic_dec_and_test(&conf->active_aligned_reads))
3931 wake_up(&conf->wait_for_stripe);
3932 return;
3933 }
3934
3935
3936 pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3937
3938 add_bio_to_retry(raid_bi, conf);
3939 }
3940
3941 static int bio_fits_rdev(struct bio *bi)
3942 {
3943 struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3944
3945 if (bio_sectors(bi) > queue_max_sectors(q))
3946 return 0;
3947 blk_recount_segments(q, bi);
3948 if (bi->bi_phys_segments > queue_max_segments(q))
3949 return 0;
3950
3951 if (q->merge_bvec_fn)
3952 /* it's too hard to apply the merge_bvec_fn at this stage,
3953 * just just give up
3954 */
3955 return 0;
3956
3957 return 1;
3958 }
3959
3960
3961 static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
3962 {
3963 struct r5conf *conf = mddev->private;
3964 int dd_idx;
3965 struct bio* align_bi;
3966 struct md_rdev *rdev;
3967 sector_t end_sector;
3968
3969 if (!in_chunk_boundary(mddev, raid_bio)) {
3970 pr_debug("chunk_aligned_read : non aligned\n");
3971 return 0;
3972 }
3973 /*
3974 * use bio_clone_mddev to make a copy of the bio
3975 */
3976 align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
3977 if (!align_bi)
3978 return 0;
3979 /*
3980 * set bi_end_io to a new function, and set bi_private to the
3981 * original bio.
3982 */
3983 align_bi->bi_end_io = raid5_align_endio;
3984 align_bi->bi_private = raid_bio;
3985 /*
3986 * compute position
3987 */
3988 align_bi->bi_sector = raid5_compute_sector(conf, raid_bio->bi_sector,
3989 0,
3990 &dd_idx, NULL);
3991
3992 end_sector = bio_end_sector(align_bi);
3993 rcu_read_lock();
3994 rdev = rcu_dereference(conf->disks[dd_idx].replacement);
3995 if (!rdev || test_bit(Faulty, &rdev->flags) ||
3996 rdev->recovery_offset < end_sector) {
3997 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
3998 if (rdev &&
3999 (test_bit(Faulty, &rdev->flags) ||
4000 !(test_bit(In_sync, &rdev->flags) ||
4001 rdev->recovery_offset >= end_sector)))
4002 rdev = NULL;
4003 }
4004 if (rdev) {
4005 sector_t first_bad;
4006 int bad_sectors;
4007
4008 atomic_inc(&rdev->nr_pending);
4009 rcu_read_unlock();
4010 raid_bio->bi_next = (void*)rdev;
4011 align_bi->bi_bdev = rdev->bdev;
4012 align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);
4013
4014 if (!bio_fits_rdev(align_bi) ||
4015 is_badblock(rdev, align_bi->bi_sector, bio_sectors(align_bi),
4016 &first_bad, &bad_sectors)) {
4017 /* too big in some way, or has a known bad block */
4018 bio_put(align_bi);
4019 rdev_dec_pending(rdev, mddev);
4020 return 0;
4021 }
4022
4023 /* No reshape active, so we can trust rdev->data_offset */
4024 align_bi->bi_sector += rdev->data_offset;
4025
4026 spin_lock_irq(&conf->device_lock);
4027 wait_event_lock_irq(conf->wait_for_stripe,
4028 conf->quiesce == 0,
4029 conf->device_lock);
4030 atomic_inc(&conf->active_aligned_reads);
4031 spin_unlock_irq(&conf->device_lock);
4032
4033 if (mddev->gendisk)
4034 trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
4035 align_bi, disk_devt(mddev->gendisk),
4036 raid_bio->bi_sector);
4037 generic_make_request(align_bi);
4038 return 1;
4039 } else {
4040 rcu_read_unlock();
4041 bio_put(align_bi);
4042 return 0;
4043 }
4044 }
4045
4046 /* __get_priority_stripe - get the next stripe to process
4047 *
4048 * Full stripe writes are allowed to pass preread active stripes up until
4049 * the bypass_threshold is exceeded. In general the bypass_count
4050 * increments when the handle_list is handled before the hold_list; however, it
4051 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
4052 * stripe with in flight i/o. The bypass_count will be reset when the
4053 * head of the hold_list has changed, i.e. the head was promoted to the
4054 * handle_list.
4055 */
4056 static struct stripe_head *__get_priority_stripe(struct r5conf *conf)
4057 {
4058 struct stripe_head *sh;
4059
4060 pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
4061 __func__,
4062 list_empty(&conf->handle_list) ? "empty" : "busy",
4063 list_empty(&conf->hold_list) ? "empty" : "busy",
4064 atomic_read(&conf->pending_full_writes), conf->bypass_count);
4065
4066 if (!list_empty(&conf->handle_list)) {
4067 sh = list_entry(conf->handle_list.next, typeof(*sh), lru);
4068
4069 if (list_empty(&conf->hold_list))
4070 conf->bypass_count = 0;
4071 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
4072 if (conf->hold_list.next == conf->last_hold)
4073 conf->bypass_count++;
4074 else {
4075 conf->last_hold = conf->hold_list.next;
4076 conf->bypass_count -= conf->bypass_threshold;
4077 if (conf->bypass_count < 0)
4078 conf->bypass_count = 0;
4079 }
4080 }
4081 } else if (!list_empty(&conf->hold_list) &&
4082 ((conf->bypass_threshold &&
4083 conf->bypass_count > conf->bypass_threshold) ||
4084 atomic_read(&conf->pending_full_writes) == 0)) {
4085 sh = list_entry(conf->hold_list.next,
4086 typeof(*sh), lru);
4087 conf->bypass_count -= conf->bypass_threshold;
4088 if (conf->bypass_count < 0)
4089 conf->bypass_count = 0;
4090 } else
4091 return NULL;
4092
4093 list_del_init(&sh->lru);
4094 atomic_inc(&sh->count);
4095 BUG_ON(atomic_read(&sh->count) != 1);
4096 return sh;
4097 }
4098
4099 struct raid5_plug_cb {
4100 struct blk_plug_cb cb;
4101 struct list_head list;
4102 };
4103
4104 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
4105 {
4106 struct raid5_plug_cb *cb = container_of(
4107 blk_cb, struct raid5_plug_cb, cb);
4108 struct stripe_head *sh;
4109 struct mddev *mddev = cb->cb.data;
4110 struct r5conf *conf = mddev->private;
4111 int cnt = 0;
4112
4113 if (cb->list.next && !list_empty(&cb->list)) {
4114 spin_lock_irq(&conf->device_lock);
4115 while (!list_empty(&cb->list)) {
4116 sh = list_first_entry(&cb->list, struct stripe_head, lru);
4117 list_del_init(&sh->lru);
4118 /*
4119 * avoid race release_stripe_plug() sees
4120 * STRIPE_ON_UNPLUG_LIST clear but the stripe
4121 * is still in our list
4122 */
4123 smp_mb__before_clear_bit();
4124 clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
4125 __release_stripe(conf, sh);
4126 cnt++;
4127 }
4128 spin_unlock_irq(&conf->device_lock);
4129 }
4130 if (mddev->queue)
4131 trace_block_unplug(mddev->queue, cnt, !from_schedule);
4132 kfree(cb);
4133 }
4134
4135 static void release_stripe_plug(struct mddev *mddev,
4136 struct stripe_head *sh)
4137 {
4138 struct blk_plug_cb *blk_cb = blk_check_plugged(
4139 raid5_unplug, mddev,
4140 sizeof(struct raid5_plug_cb));
4141 struct raid5_plug_cb *cb;
4142
4143 if (!blk_cb) {
4144 release_stripe(sh);
4145 return;
4146 }
4147
4148 cb = container_of(blk_cb, struct raid5_plug_cb, cb);
4149
4150 if (cb->list.next == NULL)
4151 INIT_LIST_HEAD(&cb->list);
4152
4153 if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
4154 list_add_tail(&sh->lru, &cb->list);
4155 else
4156 release_stripe(sh);
4157 }
4158
4159 static void make_discard_request(struct mddev *mddev, struct bio *bi)
4160 {
4161 struct r5conf *conf = mddev->private;
4162 sector_t logical_sector, last_sector;
4163 struct stripe_head *sh;
4164 int remaining;
4165 int stripe_sectors;
4166
4167 if (mddev->reshape_position != MaxSector)
4168 /* Skip discard while reshape is happening */
4169 return;
4170
4171 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
4172 last_sector = bi->bi_sector + (bi->bi_size>>9);
4173
4174 bi->bi_next = NULL;
4175 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
4176
4177 stripe_sectors = conf->chunk_sectors *
4178 (conf->raid_disks - conf->max_degraded);
4179 logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
4180 stripe_sectors);
4181 sector_div(last_sector, stripe_sectors);
4182
4183 logical_sector *= conf->chunk_sectors;
4184 last_sector *= conf->chunk_sectors;
4185
4186 for (; logical_sector < last_sector;
4187 logical_sector += STRIPE_SECTORS) {
4188 DEFINE_WAIT(w);
4189 int d;
4190 again:
4191 sh = get_active_stripe(conf, logical_sector, 0, 0, 0);
4192 prepare_to_wait(&conf->wait_for_overlap, &w,
4193 TASK_UNINTERRUPTIBLE);
4194 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
4195 if (test_bit(STRIPE_SYNCING, &sh->state)) {
4196 release_stripe(sh);
4197 schedule();
4198 goto again;
4199 }
4200 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
4201 spin_lock_irq(&sh->stripe_lock);
4202 for (d = 0; d < conf->raid_disks; d++) {
4203 if (d == sh->pd_idx || d == sh->qd_idx)
4204 continue;
4205 if (sh->dev[d].towrite || sh->dev[d].toread) {
4206 set_bit(R5_Overlap, &sh->dev[d].flags);
4207 spin_unlock_irq(&sh->stripe_lock);
4208 release_stripe(sh);
4209 schedule();
4210 goto again;
4211 }
4212 }
4213 set_bit(STRIPE_DISCARD, &sh->state);
4214 finish_wait(&conf->wait_for_overlap, &w);
4215 for (d = 0; d < conf->raid_disks; d++) {
4216 if (d == sh->pd_idx || d == sh->qd_idx)
4217 continue;
4218 sh->dev[d].towrite = bi;
4219 set_bit(R5_OVERWRITE, &sh->dev[d].flags);
4220 raid5_inc_bi_active_stripes(bi);
4221 }
4222 spin_unlock_irq(&sh->stripe_lock);
4223 if (conf->mddev->bitmap) {
4224 for (d = 0;
4225 d < conf->raid_disks - conf->max_degraded;
4226 d++)
4227 bitmap_startwrite(mddev->bitmap,
4228 sh->sector,
4229 STRIPE_SECTORS,
4230 0);
4231 sh->bm_seq = conf->seq_flush + 1;
4232 set_bit(STRIPE_BIT_DELAY, &sh->state);
4233 }
4234
4235 set_bit(STRIPE_HANDLE, &sh->state);
4236 clear_bit(STRIPE_DELAYED, &sh->state);
4237 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4238 atomic_inc(&conf->preread_active_stripes);
4239 release_stripe_plug(mddev, sh);
4240 }
4241
4242 remaining = raid5_dec_bi_active_stripes(bi);
4243 if (remaining == 0) {
4244 md_write_end(mddev);
4245 bio_endio(bi, 0);
4246 }
4247 }
4248
4249 static void make_request(struct mddev *mddev, struct bio * bi)
4250 {
4251 struct r5conf *conf = mddev->private;
4252 int dd_idx;
4253 sector_t new_sector;
4254 sector_t logical_sector, last_sector;
4255 struct stripe_head *sh;
4256 const int rw = bio_data_dir(bi);
4257 int remaining;
4258
4259 if (unlikely(bi->bi_rw & REQ_FLUSH)) {
4260 md_flush_request(mddev, bi);
4261 return;
4262 }
4263
4264 md_write_start(mddev, bi);
4265
4266 if (rw == READ &&
4267 mddev->reshape_position == MaxSector &&
4268 chunk_aligned_read(mddev,bi))
4269 return;
4270
4271 if (unlikely(bi->bi_rw & REQ_DISCARD)) {
4272 make_discard_request(mddev, bi);
4273 return;
4274 }
4275
4276 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
4277 last_sector = bio_end_sector(bi);
4278 bi->bi_next = NULL;
4279 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
4280
4281 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
4282 DEFINE_WAIT(w);
4283 int previous;
4284
4285 retry:
4286 previous = 0;
4287 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
4288 if (unlikely(conf->reshape_progress != MaxSector)) {
4289 /* spinlock is needed as reshape_progress may be
4290 * 64bit on a 32bit platform, and so it might be
4291 * possible to see a half-updated value
4292 * Of course reshape_progress could change after
4293 * the lock is dropped, so once we get a reference
4294 * to the stripe that we think it is, we will have
4295 * to check again.
4296 */
4297 spin_lock_irq(&conf->device_lock);
4298 if (mddev->reshape_backwards
4299 ? logical_sector < conf->reshape_progress
4300 : logical_sector >= conf->reshape_progress) {
4301 previous = 1;
4302 } else {
4303 if (mddev->reshape_backwards
4304 ? logical_sector < conf->reshape_safe
4305 : logical_sector >= conf->reshape_safe) {
4306 spin_unlock_irq(&conf->device_lock);
4307 schedule();
4308 goto retry;
4309 }
4310 }
4311 spin_unlock_irq(&conf->device_lock);
4312 }
4313
4314 new_sector = raid5_compute_sector(conf, logical_sector,
4315 previous,
4316 &dd_idx, NULL);
4317 pr_debug("raid456: make_request, sector %llu logical %llu\n",
4318 (unsigned long long)new_sector,
4319 (unsigned long long)logical_sector);
4320
4321 sh = get_active_stripe(conf, new_sector, previous,
4322 (bi->bi_rw&RWA_MASK), 0);
4323 if (sh) {
4324 if (unlikely(previous)) {
4325 /* expansion might have moved on while waiting for a
4326 * stripe, so we must do the range check again.
4327 * Expansion could still move past after this
4328 * test, but as we are holding a reference to
4329 * 'sh', we know that if that happens,
4330 * STRIPE_EXPANDING will get set and the expansion
4331 * won't proceed until we finish with the stripe.
4332 */
4333 int must_retry = 0;
4334 spin_lock_irq(&conf->device_lock);
4335 if (mddev->reshape_backwards
4336 ? logical_sector >= conf->reshape_progress
4337 : logical_sector < conf->reshape_progress)
4338 /* mismatch, need to try again */
4339 must_retry = 1;
4340 spin_unlock_irq(&conf->device_lock);
4341 if (must_retry) {
4342 release_stripe(sh);
4343 schedule();
4344 goto retry;
4345 }
4346 }
4347
4348 if (rw == WRITE &&
4349 logical_sector >= mddev->suspend_lo &&
4350 logical_sector < mddev->suspend_hi) {
4351 release_stripe(sh);
4352 /* As the suspend_* range is controlled by
4353 * userspace, we want an interruptible
4354 * wait.
4355 */
4356 flush_signals(current);
4357 prepare_to_wait(&conf->wait_for_overlap,
4358 &w, TASK_INTERRUPTIBLE);
4359 if (logical_sector >= mddev->suspend_lo &&
4360 logical_sector < mddev->suspend_hi)
4361 schedule();
4362 goto retry;
4363 }
4364
4365 if (test_bit(STRIPE_EXPANDING, &sh->state) ||
4366 !add_stripe_bio(sh, bi, dd_idx, rw)) {
4367 /* Stripe is busy expanding or
4368 * add failed due to overlap. Flush everything
4369 * and wait a while
4370 */
4371 md_wakeup_thread(mddev->thread);
4372 release_stripe(sh);
4373 schedule();
4374 goto retry;
4375 }
4376 finish_wait(&conf->wait_for_overlap, &w);
4377 set_bit(STRIPE_HANDLE, &sh->state);
4378 clear_bit(STRIPE_DELAYED, &sh->state);
4379 if ((bi->bi_rw & REQ_SYNC) &&
4380 !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4381 atomic_inc(&conf->preread_active_stripes);
4382 release_stripe_plug(mddev, sh);
4383 } else {
4384 /* cannot get stripe for read-ahead, just give-up */
4385 clear_bit(BIO_UPTODATE, &bi->bi_flags);
4386 finish_wait(&conf->wait_for_overlap, &w);
4387 break;
4388 }
4389 }
4390
4391 remaining = raid5_dec_bi_active_stripes(bi);
4392 if (remaining == 0) {
4393
4394 if ( rw == WRITE )
4395 md_write_end(mddev);
4396
4397 trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
4398 bi, 0);
4399 bio_endio(bi, 0);
4400 }
4401 }
4402
4403 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
4404
4405 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
4406 {
4407 /* reshaping is quite different to recovery/resync so it is
4408 * handled quite separately ... here.
4409 *
4410 * On each call to sync_request, we gather one chunk worth of
4411 * destination stripes and flag them as expanding.
4412 * Then we find all the source stripes and request reads.
4413 * As the reads complete, handle_stripe will copy the data
4414 * into the destination stripe and release that stripe.
4415 */
4416 struct r5conf *conf = mddev->private;
4417 struct stripe_head *sh;
4418 sector_t first_sector, last_sector;
4419 int raid_disks = conf->previous_raid_disks;
4420 int data_disks = raid_disks - conf->max_degraded;
4421 int new_data_disks = conf->raid_disks - conf->max_degraded;
4422 int i;
4423 int dd_idx;
4424 sector_t writepos, readpos, safepos;
4425 sector_t stripe_addr;
4426 int reshape_sectors;
4427 struct list_head stripes;
4428
4429 if (sector_nr == 0) {
4430 /* If restarting in the middle, skip the initial sectors */
4431 if (mddev->reshape_backwards &&
4432 conf->reshape_progress < raid5_size(mddev, 0, 0)) {
4433 sector_nr = raid5_size(mddev, 0, 0)
4434 - conf->reshape_progress;
4435 } else if (!mddev->reshape_backwards &&
4436 conf->reshape_progress > 0)
4437 sector_nr = conf->reshape_progress;
4438 sector_div(sector_nr, new_data_disks);
4439 if (sector_nr) {
4440 mddev->curr_resync_completed = sector_nr;
4441 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4442 *skipped = 1;
4443 return sector_nr;
4444 }
4445 }
4446
4447 /* We need to process a full chunk at a time.
4448 * If old and new chunk sizes differ, we need to process the
4449 * largest of these
4450 */
4451 if (mddev->new_chunk_sectors > mddev->chunk_sectors)
4452 reshape_sectors = mddev->new_chunk_sectors;
4453 else
4454 reshape_sectors = mddev->chunk_sectors;
4455
4456 /* We update the metadata at least every 10 seconds, or when
4457 * the data about to be copied would over-write the source of
4458 * the data at the front of the range. i.e. one new_stripe
4459 * along from reshape_progress new_maps to after where
4460 * reshape_safe old_maps to
4461 */
4462 writepos = conf->reshape_progress;
4463 sector_div(writepos, new_data_disks);
4464 readpos = conf->reshape_progress;
4465 sector_div(readpos, data_disks);
4466 safepos = conf->reshape_safe;
4467 sector_div(safepos, data_disks);
4468 if (mddev->reshape_backwards) {
4469 writepos -= min_t(sector_t, reshape_sectors, writepos);
4470 readpos += reshape_sectors;
4471 safepos += reshape_sectors;
4472 } else {
4473 writepos += reshape_sectors;
4474 readpos -= min_t(sector_t, reshape_sectors, readpos);
4475 safepos -= min_t(sector_t, reshape_sectors, safepos);
4476 }
4477
4478 /* Having calculated the 'writepos' possibly use it
4479 * to set 'stripe_addr' which is where we will write to.
4480 */
4481 if (mddev->reshape_backwards) {
4482 BUG_ON(conf->reshape_progress == 0);
4483 stripe_addr = writepos;
4484 BUG_ON((mddev->dev_sectors &
4485 ~((sector_t)reshape_sectors - 1))
4486 - reshape_sectors - stripe_addr
4487 != sector_nr);
4488 } else {
4489 BUG_ON(writepos != sector_nr + reshape_sectors);
4490 stripe_addr = sector_nr;
4491 }
4492
4493 /* 'writepos' is the most advanced device address we might write.
4494 * 'readpos' is the least advanced device address we might read.
4495 * 'safepos' is the least address recorded in the metadata as having
4496 * been reshaped.
4497 * If there is a min_offset_diff, these are adjusted either by
4498 * increasing the safepos/readpos if diff is negative, or
4499 * increasing writepos if diff is positive.
4500 * If 'readpos' is then behind 'writepos', there is no way that we can
4501 * ensure safety in the face of a crash - that must be done by userspace
4502 * making a backup of the data. So in that case there is no particular
4503 * rush to update metadata.
4504 * Otherwise if 'safepos' is behind 'writepos', then we really need to
4505 * update the metadata to advance 'safepos' to match 'readpos' so that
4506 * we can be safe in the event of a crash.
4507 * So we insist on updating metadata if safepos is behind writepos and
4508 * readpos is beyond writepos.
4509 * In any case, update the metadata every 10 seconds.
4510 * Maybe that number should be configurable, but I'm not sure it is
4511 * worth it.... maybe it could be a multiple of safemode_delay???
4512 */
4513 if (conf->min_offset_diff < 0) {
4514 safepos += -conf->min_offset_diff;
4515 readpos += -conf->min_offset_diff;
4516 } else
4517 writepos += conf->min_offset_diff;
4518
4519 if ((mddev->reshape_backwards
4520 ? (safepos > writepos && readpos < writepos)
4521 : (safepos < writepos && readpos > writepos)) ||
4522 time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4523 /* Cannot proceed until we've updated the superblock... */
4524 wait_event(conf->wait_for_overlap,
4525 atomic_read(&conf->reshape_stripes)==0);
4526 mddev->reshape_position = conf->reshape_progress;
4527 mddev->curr_resync_completed = sector_nr;
4528 conf->reshape_checkpoint = jiffies;
4529 set_bit(MD_CHANGE_DEVS, &mddev->flags);
4530 md_wakeup_thread(mddev->thread);
4531 wait_event(mddev->sb_wait, mddev->flags == 0 ||
4532 kthread_should_stop());
4533 spin_lock_irq(&conf->device_lock);
4534 conf->reshape_safe = mddev->reshape_position;
4535 spin_unlock_irq(&conf->device_lock);
4536 wake_up(&conf->wait_for_overlap);
4537 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4538 }
4539
4540 INIT_LIST_HEAD(&stripes);
4541 for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
4542 int j;
4543 int skipped_disk = 0;
4544 sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
4545 set_bit(STRIPE_EXPANDING, &sh->state);
4546 atomic_inc(&conf->reshape_stripes);
4547 /* If any of this stripe is beyond the end of the old
4548 * array, then we need to zero those blocks
4549 */
4550 for (j=sh->disks; j--;) {
4551 sector_t s;
4552 if (j == sh->pd_idx)
4553 continue;
4554 if (conf->level == 6 &&
4555 j == sh->qd_idx)
4556 continue;
4557 s = compute_blocknr(sh, j, 0);
4558 if (s < raid5_size(mddev, 0, 0)) {
4559 skipped_disk = 1;
4560 continue;
4561 }
4562 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
4563 set_bit(R5_Expanded, &sh->dev[j].flags);
4564 set_bit(R5_UPTODATE, &sh->dev[j].flags);
4565 }
4566 if (!skipped_disk) {
4567 set_bit(STRIPE_EXPAND_READY, &sh->state);
4568 set_bit(STRIPE_HANDLE, &sh->state);
4569 }
4570 list_add(&sh->lru, &stripes);
4571 }
4572 spin_lock_irq(&conf->device_lock);
4573 if (mddev->reshape_backwards)
4574 conf->reshape_progress -= reshape_sectors * new_data_disks;
4575 else
4576 conf->reshape_progress += reshape_sectors * new_data_disks;
4577 spin_unlock_irq(&conf->device_lock);
4578 /* Ok, those stripe are ready. We can start scheduling
4579 * reads on the source stripes.
4580 * The source stripes are determined by mapping the first and last
4581 * block on the destination stripes.
4582 */
4583 first_sector =
4584 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
4585 1, &dd_idx, NULL);
4586 last_sector =
4587 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
4588 * new_data_disks - 1),
4589 1, &dd_idx, NULL);
4590 if (last_sector >= mddev->dev_sectors)
4591 last_sector = mddev->dev_sectors - 1;
4592 while (first_sector <= last_sector) {
4593 sh = get_active_stripe(conf, first_sector, 1, 0, 1);
4594 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4595 set_bit(STRIPE_HANDLE, &sh->state);
4596 release_stripe(sh);
4597 first_sector += STRIPE_SECTORS;
4598 }
4599 /* Now that the sources are clearly marked, we can release
4600 * the destination stripes
4601 */
4602 while (!list_empty(&stripes)) {
4603 sh = list_entry(stripes.next, struct stripe_head, lru);
4604 list_del_init(&sh->lru);
4605 release_stripe(sh);
4606 }
4607 /* If this takes us to the resync_max point where we have to pause,
4608 * then we need to write out the superblock.
4609 */
4610 sector_nr += reshape_sectors;
4611 if ((sector_nr - mddev->curr_resync_completed) * 2
4612 >= mddev->resync_max - mddev->curr_resync_completed) {
4613 /* Cannot proceed until we've updated the superblock... */
4614 wait_event(conf->wait_for_overlap,
4615 atomic_read(&conf->reshape_stripes) == 0);
4616 mddev->reshape_position = conf->reshape_progress;
4617 mddev->curr_resync_completed = sector_nr;
4618 conf->reshape_checkpoint = jiffies;
4619 set_bit(MD_CHANGE_DEVS, &mddev->flags);
4620 md_wakeup_thread(mddev->thread);
4621 wait_event(mddev->sb_wait,
4622 !test_bit(MD_CHANGE_DEVS, &mddev->flags)
4623 || kthread_should_stop());
4624 spin_lock_irq(&conf->device_lock);
4625 conf->reshape_safe = mddev->reshape_position;
4626 spin_unlock_irq(&conf->device_lock);
4627 wake_up(&conf->wait_for_overlap);
4628 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4629 }
4630 return reshape_sectors;
4631 }
4632
4633 /* FIXME go_faster isn't used */
4634 static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
4635 {
4636 struct r5conf *conf = mddev->private;
4637 struct stripe_head *sh;
4638 sector_t max_sector = mddev->dev_sectors;
4639 sector_t sync_blocks;
4640 int still_degraded = 0;
4641 int i;
4642
4643 if (sector_nr >= max_sector) {
4644 /* just being told to finish up .. nothing much to do */
4645
4646 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
4647 end_reshape(conf);
4648 return 0;
4649 }
4650
4651 if (mddev->curr_resync < max_sector) /* aborted */
4652 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
4653 &sync_blocks, 1);
4654 else /* completed sync */
4655 conf->fullsync = 0;
4656 bitmap_close_sync(mddev->bitmap);
4657
4658 return 0;
4659 }
4660
4661 /* Allow raid5_quiesce to complete */
4662 wait_event(conf->wait_for_overlap, conf->quiesce != 2);
4663
4664 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
4665 return reshape_request(mddev, sector_nr, skipped);
4666
4667 /* No need to check resync_max as we never do more than one
4668 * stripe, and as resync_max will always be on a chunk boundary,
4669 * if the check in md_do_sync didn't fire, there is no chance
4670 * of overstepping resync_max here
4671 */
4672
4673 /* if there is too many failed drives and we are trying
4674 * to resync, then assert that we are finished, because there is
4675 * nothing we can do.
4676 */
4677 if (mddev->degraded >= conf->max_degraded &&
4678 test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
4679 sector_t rv = mddev->dev_sectors - sector_nr;
4680 *skipped = 1;
4681 return rv;
4682 }
4683 if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
4684 !conf->fullsync &&
4685 !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
4686 sync_blocks >= STRIPE_SECTORS) {
4687 /* we can skip this block, and probably more */
4688 sync_blocks /= STRIPE_SECTORS;
4689 *skipped = 1;
4690 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
4691 }
4692
4693 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
4694
4695 sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
4696 if (sh == NULL) {
4697 sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
4698 /* make sure we don't swamp the stripe cache if someone else
4699 * is trying to get access
4700 */
4701 schedule_timeout_uninterruptible(1);
4702 }
4703 /* Need to check if array will still be degraded after recovery/resync
4704 * We don't need to check the 'failed' flag as when that gets set,
4705 * recovery aborts.
4706 */
4707 for (i = 0; i < conf->raid_disks; i++)
4708 if (conf->disks[i].rdev == NULL)
4709 still_degraded = 1;
4710
4711 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
4712
4713 set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
4714
4715 handle_stripe(sh);
4716 release_stripe(sh);
4717
4718 return STRIPE_SECTORS;
4719 }
4720
4721 static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
4722 {
4723 /* We may not be able to submit a whole bio at once as there
4724 * may not be enough stripe_heads available.
4725 * We cannot pre-allocate enough stripe_heads as we may need
4726 * more than exist in the cache (if we allow ever large chunks).
4727 * So we do one stripe head at a time and record in
4728 * ->bi_hw_segments how many have been done.
4729 *
4730 * We *know* that this entire raid_bio is in one chunk, so
4731 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
4732 */
4733 struct stripe_head *sh;
4734 int dd_idx;
4735 sector_t sector, logical_sector, last_sector;
4736 int scnt = 0;
4737 int remaining;
4738 int handled = 0;
4739
4740 logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
4741 sector = raid5_compute_sector(conf, logical_sector,
4742 0, &dd_idx, NULL);
4743 last_sector = bio_end_sector(raid_bio);
4744
4745 for (; logical_sector < last_sector;
4746 logical_sector += STRIPE_SECTORS,
4747 sector += STRIPE_SECTORS,
4748 scnt++) {
4749
4750 if (scnt < raid5_bi_processed_stripes(raid_bio))
4751 /* already done this stripe */
4752 continue;
4753
4754 sh = get_active_stripe(conf, sector, 0, 1, 0);
4755
4756 if (!sh) {
4757 /* failed to get a stripe - must wait */
4758 raid5_set_bi_processed_stripes(raid_bio, scnt);
4759 conf->retry_read_aligned = raid_bio;
4760 return handled;
4761 }
4762
4763 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
4764 release_stripe(sh);
4765 raid5_set_bi_processed_stripes(raid_bio, scnt);
4766 conf->retry_read_aligned = raid_bio;
4767 return handled;
4768 }
4769
4770 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
4771 handle_stripe(sh);
4772 release_stripe(sh);
4773 handled++;
4774 }
4775 remaining = raid5_dec_bi_active_stripes(raid_bio);
4776 if (remaining == 0) {
4777 trace_block_bio_complete(bdev_get_queue(raid_bio->bi_bdev),
4778 raid_bio, 0);
4779 bio_endio(raid_bio, 0);
4780 }
4781 if (atomic_dec_and_test(&conf->active_aligned_reads))
4782 wake_up(&conf->wait_for_stripe);
4783 return handled;
4784 }
4785
4786 #define MAX_STRIPE_BATCH 8
4787 static int handle_active_stripes(struct r5conf *conf)
4788 {
4789 struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
4790 int i, batch_size = 0;
4791
4792 while (batch_size < MAX_STRIPE_BATCH &&
4793 (sh = __get_priority_stripe(conf)) != NULL)
4794 batch[batch_size++] = sh;
4795
4796 if (batch_size == 0)
4797 return batch_size;
4798 spin_unlock_irq(&conf->device_lock);
4799
4800 for (i = 0; i < batch_size; i++)
4801 handle_stripe(batch[i]);
4802
4803 cond_resched();
4804
4805 spin_lock_irq(&conf->device_lock);
4806 for (i = 0; i < batch_size; i++)
4807 __release_stripe(conf, batch[i]);
4808 return batch_size;
4809 }
4810
4811 /*
4812 * This is our raid5 kernel thread.
4813 *
4814 * We scan the hash table for stripes which can be handled now.
4815 * During the scan, completed stripes are saved for us by the interrupt
4816 * handler, so that they will not have to wait for our next wakeup.
4817 */
4818 static void raid5d(struct md_thread *thread)
4819 {
4820 struct mddev *mddev = thread->mddev;
4821 struct r5conf *conf = mddev->private;
4822 int handled;
4823 struct blk_plug plug;
4824
4825 pr_debug("+++ raid5d active\n");
4826
4827 md_check_recovery(mddev);
4828
4829 blk_start_plug(&plug);
4830 handled = 0;
4831 spin_lock_irq(&conf->device_lock);
4832 while (1) {
4833 struct bio *bio;
4834 int batch_size;
4835
4836 if (
4837 !list_empty(&conf->bitmap_list)) {
4838 /* Now is a good time to flush some bitmap updates */
4839 conf->seq_flush++;
4840 spin_unlock_irq(&conf->device_lock);
4841 bitmap_unplug(mddev->bitmap);
4842 spin_lock_irq(&conf->device_lock);
4843 conf->seq_write = conf->seq_flush;
4844 activate_bit_delay(conf);
4845 }
4846 raid5_activate_delayed(conf);
4847
4848 while ((bio = remove_bio_from_retry(conf))) {
4849 int ok;
4850 spin_unlock_irq(&conf->device_lock);
4851 ok = retry_aligned_read(conf, bio);
4852 spin_lock_irq(&conf->device_lock);
4853 if (!ok)
4854 break;
4855 handled++;
4856 }
4857
4858 batch_size = handle_active_stripes(conf);
4859 if (!batch_size)
4860 break;
4861 handled += batch_size;
4862
4863 if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) {
4864 spin_unlock_irq(&conf->device_lock);
4865 md_check_recovery(mddev);
4866 spin_lock_irq(&conf->device_lock);
4867 }
4868 }
4869 pr_debug("%d stripes handled\n", handled);
4870
4871 spin_unlock_irq(&conf->device_lock);
4872
4873 async_tx_issue_pending_all();
4874 blk_finish_plug(&plug);
4875
4876 pr_debug("--- raid5d inactive\n");
4877 }
4878
4879 static ssize_t
4880 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
4881 {
4882 struct r5conf *conf = mddev->private;
4883 if (conf)
4884 return sprintf(page, "%d\n", conf->max_nr_stripes);
4885 else
4886 return 0;
4887 }
4888
4889 int
4890 raid5_set_cache_size(struct mddev *mddev, int size)
4891 {
4892 struct r5conf *conf = mddev->private;
4893 int err;
4894
4895 if (size <= 16 || size > 32768)
4896 return -EINVAL;
4897 while (size < conf->max_nr_stripes) {
4898 if (drop_one_stripe(conf))
4899 conf->max_nr_stripes--;
4900 else
4901 break;
4902 }
4903 err = md_allow_write(mddev);
4904 if (err)
4905 return err;
4906 while (size > conf->max_nr_stripes) {
4907 if (grow_one_stripe(conf))
4908 conf->max_nr_stripes++;
4909 else break;
4910 }
4911 return 0;
4912 }
4913 EXPORT_SYMBOL(raid5_set_cache_size);
4914
4915 static ssize_t
4916 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
4917 {
4918 struct r5conf *conf = mddev->private;
4919 unsigned long new;
4920 int err;
4921
4922 if (len >= PAGE_SIZE)
4923 return -EINVAL;
4924 if (!conf)
4925 return -ENODEV;
4926
4927 if (strict_strtoul(page, 10, &new))
4928 return -EINVAL;
4929 err = raid5_set_cache_size(mddev, new);
4930 if (err)
4931 return err;
4932 return len;
4933 }
4934
4935 static struct md_sysfs_entry
4936 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
4937 raid5_show_stripe_cache_size,
4938 raid5_store_stripe_cache_size);
4939
4940 static ssize_t
4941 raid5_show_preread_threshold(struct mddev *mddev, char *page)
4942 {
4943 struct r5conf *conf = mddev->private;
4944 if (conf)
4945 return sprintf(page, "%d\n", conf->bypass_threshold);
4946 else
4947 return 0;
4948 }
4949
4950 static ssize_t
4951 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
4952 {
4953 struct r5conf *conf = mddev->private;
4954 unsigned long new;
4955 if (len >= PAGE_SIZE)
4956 return -EINVAL;
4957 if (!conf)
4958 return -ENODEV;
4959
4960 if (strict_strtoul(page, 10, &new))
4961 return -EINVAL;
4962 if (new > conf->max_nr_stripes)
4963 return -EINVAL;
4964 conf->bypass_threshold = new;
4965 return len;
4966 }
4967
4968 static struct md_sysfs_entry
4969 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
4970 S_IRUGO | S_IWUSR,
4971 raid5_show_preread_threshold,
4972 raid5_store_preread_threshold);
4973
4974 static ssize_t
4975 stripe_cache_active_show(struct mddev *mddev, char *page)
4976 {
4977 struct r5conf *conf = mddev->private;
4978 if (conf)
4979 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
4980 else
4981 return 0;
4982 }
4983
4984 static struct md_sysfs_entry
4985 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4986
4987 static struct attribute *raid5_attrs[] = {
4988 &raid5_stripecache_size.attr,
4989 &raid5_stripecache_active.attr,
4990 &raid5_preread_bypass_threshold.attr,
4991 NULL,
4992 };
4993 static struct attribute_group raid5_attrs_group = {
4994 .name = NULL,
4995 .attrs = raid5_attrs,
4996 };
4997
4998 static sector_t
4999 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
5000 {
5001 struct r5conf *conf = mddev->private;
5002
5003 if (!sectors)
5004 sectors = mddev->dev_sectors;
5005 if (!raid_disks)
5006 /* size is defined by the smallest of previous and new size */
5007 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
5008
5009 sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5010 sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
5011 return sectors * (raid_disks - conf->max_degraded);
5012 }
5013
5014 static void raid5_free_percpu(struct r5conf *conf)
5015 {
5016 struct raid5_percpu *percpu;
5017 unsigned long cpu;
5018
5019 if (!conf->percpu)
5020 return;
5021
5022 get_online_cpus();
5023 for_each_possible_cpu(cpu) {
5024 percpu = per_cpu_ptr(conf->percpu, cpu);
5025 safe_put_page(percpu->spare_page);
5026 kfree(percpu->scribble);
5027 }
5028 #ifdef CONFIG_HOTPLUG_CPU
5029 unregister_cpu_notifier(&conf->cpu_notify);
5030 #endif
5031 put_online_cpus();
5032
5033 free_percpu(conf->percpu);
5034 }
5035
5036 static void free_conf(struct r5conf *conf)
5037 {
5038 shrink_stripes(conf);
5039 raid5_free_percpu(conf);
5040 kfree(conf->disks);
5041 kfree(conf->stripe_hashtbl);
5042 kfree(conf);
5043 }
5044
5045 #ifdef CONFIG_HOTPLUG_CPU
5046 static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
5047 void *hcpu)
5048 {
5049 struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);
5050 long cpu = (long)hcpu;
5051 struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
5052
5053 switch (action) {
5054 case CPU_UP_PREPARE:
5055 case CPU_UP_PREPARE_FROZEN:
5056 if (conf->level == 6 && !percpu->spare_page)
5057 percpu->spare_page = alloc_page(GFP_KERNEL);
5058 if (!percpu->scribble)
5059 percpu->scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
5060
5061 if (!percpu->scribble ||
5062 (conf->level == 6 && !percpu->spare_page)) {
5063 safe_put_page(percpu->spare_page);
5064 kfree(percpu->scribble);
5065 pr_err("%s: failed memory allocation for cpu%ld\n",
5066 __func__, cpu);
5067 return notifier_from_errno(-ENOMEM);
5068 }
5069 break;
5070 case CPU_DEAD:
5071 case CPU_DEAD_FROZEN:
5072 safe_put_page(percpu->spare_page);
5073 kfree(percpu->scribble);
5074 percpu->spare_page = NULL;
5075 percpu->scribble = NULL;
5076 break;
5077 default:
5078 break;
5079 }
5080 return NOTIFY_OK;
5081 }
5082 #endif
5083
5084 static int raid5_alloc_percpu(struct r5conf *conf)
5085 {
5086 unsigned long cpu;
5087 struct page *spare_page;
5088 struct raid5_percpu __percpu *allcpus;
5089 void *scribble;
5090 int err;
5091
5092 allcpus = alloc_percpu(struct raid5_percpu);
5093 if (!allcpus)
5094 return -ENOMEM;
5095 conf->percpu = allcpus;
5096
5097 get_online_cpus();
5098 err = 0;
5099 for_each_present_cpu(cpu) {
5100 if (conf->level == 6) {
5101 spare_page = alloc_page(GFP_KERNEL);
5102 if (!spare_page) {
5103 err = -ENOMEM;
5104 break;
5105 }
5106 per_cpu_ptr(conf->percpu, cpu)->spare_page = spare_page;
5107 }
5108 scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
5109 if (!scribble) {
5110 err = -ENOMEM;
5111 break;
5112 }
5113 per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
5114 }
5115 #ifdef CONFIG_HOTPLUG_CPU
5116 conf->cpu_notify.notifier_call = raid456_cpu_notify;
5117 conf->cpu_notify.priority = 0;
5118 if (err == 0)
5119 err = register_cpu_notifier(&conf->cpu_notify);
5120 #endif
5121 put_online_cpus();
5122
5123 return err;
5124 }
5125
5126 static struct r5conf *setup_conf(struct mddev *mddev)
5127 {
5128 struct r5conf *conf;
5129 int raid_disk, memory, max_disks;
5130 struct md_rdev *rdev;
5131 struct disk_info *disk;
5132 char pers_name[6];
5133
5134 if (mddev->new_level != 5
5135 && mddev->new_level != 4
5136 && mddev->new_level != 6) {
5137 printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
5138 mdname(mddev), mddev->new_level);
5139 return ERR_PTR(-EIO);
5140 }
5141 if ((mddev->new_level == 5
5142 && !algorithm_valid_raid5(mddev->new_layout)) ||
5143 (mddev->new_level == 6
5144 && !algorithm_valid_raid6(mddev->new_layout))) {
5145 printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
5146 mdname(mddev), mddev->new_layout);
5147 return ERR_PTR(-EIO);
5148 }
5149 if (mddev->new_level == 6 && mddev->raid_disks < 4) {
5150 printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
5151 mdname(mddev), mddev->raid_disks);
5152 return ERR_PTR(-EINVAL);
5153 }
5154
5155 if (!mddev->new_chunk_sectors ||
5156 (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
5157 !is_power_of_2(mddev->new_chunk_sectors)) {
5158 printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
5159 mdname(mddev), mddev->new_chunk_sectors << 9);
5160 return ERR_PTR(-EINVAL);
5161 }
5162
5163 conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
5164 if (conf == NULL)
5165 goto abort;
5166 spin_lock_init(&conf->device_lock);
5167 init_waitqueue_head(&conf->wait_for_stripe);
5168 init_waitqueue_head(&conf->wait_for_overlap);
5169 INIT_LIST_HEAD(&conf->handle_list);
5170 INIT_LIST_HEAD(&conf->hold_list);
5171 INIT_LIST_HEAD(&conf->delayed_list);
5172 INIT_LIST_HEAD(&conf->bitmap_list);
5173 INIT_LIST_HEAD(&conf->inactive_list);
5174 atomic_set(&conf->active_stripes, 0);
5175 atomic_set(&conf->preread_active_stripes, 0);
5176 atomic_set(&conf->active_aligned_reads, 0);
5177 conf->bypass_threshold = BYPASS_THRESHOLD;
5178 conf->recovery_disabled = mddev->recovery_disabled - 1;
5179
5180 conf->raid_disks = mddev->raid_disks;
5181 if (mddev->reshape_position == MaxSector)
5182 conf->previous_raid_disks = mddev->raid_disks;
5183 else
5184 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
5185 max_disks = max(conf->raid_disks, conf->previous_raid_disks);
5186 conf->scribble_len = scribble_len(max_disks);
5187
5188 conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
5189 GFP_KERNEL);
5190 if (!conf->disks)
5191 goto abort;
5192
5193 conf->mddev = mddev;
5194
5195 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
5196 goto abort;
5197
5198 conf->level = mddev->new_level;
5199 if (raid5_alloc_percpu(conf) != 0)
5200 goto abort;
5201
5202 pr_debug("raid456: run(%s) called.\n", mdname(mddev));
5203
5204 rdev_for_each(rdev, mddev) {
5205 raid_disk = rdev->raid_disk;
5206 if (raid_disk >= max_disks
5207 || raid_disk < 0)
5208 continue;
5209 disk = conf->disks + raid_disk;
5210
5211 if (test_bit(Replacement, &rdev->flags)) {
5212 if (disk->replacement)
5213 goto abort;
5214 disk->replacement = rdev;
5215 } else {
5216 if (disk->rdev)
5217 goto abort;
5218 disk->rdev = rdev;
5219 }
5220
5221 if (test_bit(In_sync, &rdev->flags)) {
5222 char b[BDEVNAME_SIZE];
5223 printk(KERN_INFO "md/raid:%s: device %s operational as raid"
5224 " disk %d\n",
5225 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
5226 } else if (rdev->saved_raid_disk != raid_disk)
5227 /* Cannot rely on bitmap to complete recovery */
5228 conf->fullsync = 1;
5229 }
5230
5231 conf->chunk_sectors = mddev->new_chunk_sectors;
5232 conf->level = mddev->new_level;
5233 if (conf->level == 6)
5234 conf->max_degraded = 2;
5235 else
5236 conf->max_degraded = 1;
5237 conf->algorithm = mddev->new_layout;
5238 conf->max_nr_stripes = NR_STRIPES;
5239 conf->reshape_progress = mddev->reshape_position;
5240 if (conf->reshape_progress != MaxSector) {
5241 conf->prev_chunk_sectors = mddev->chunk_sectors;
5242 conf->prev_algo = mddev->layout;
5243 }
5244
5245 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
5246 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
5247 if (grow_stripes(conf, conf->max_nr_stripes)) {
5248 printk(KERN_ERR
5249 "md/raid:%s: couldn't allocate %dkB for buffers\n",
5250 mdname(mddev), memory);
5251 goto abort;
5252 } else
5253 printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
5254 mdname(mddev), memory);
5255
5256 sprintf(pers_name, "raid%d", mddev->new_level);
5257 conf->thread = md_register_thread(raid5d, mddev, pers_name);
5258 if (!conf->thread) {
5259 printk(KERN_ERR
5260 "md/raid:%s: couldn't allocate thread.\n",
5261 mdname(mddev));
5262 goto abort;
5263 }
5264
5265 return conf;
5266
5267 abort:
5268 if (conf) {
5269 free_conf(conf);
5270 return ERR_PTR(-EIO);
5271 } else
5272 return ERR_PTR(-ENOMEM);
5273 }
5274
5275
5276 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
5277 {
5278 switch (algo) {
5279 case ALGORITHM_PARITY_0:
5280 if (raid_disk < max_degraded)
5281 return 1;
5282 break;
5283 case ALGORITHM_PARITY_N:
5284 if (raid_disk >= raid_disks - max_degraded)
5285 return 1;
5286 break;
5287 case ALGORITHM_PARITY_0_6:
5288 if (raid_disk == 0 ||
5289 raid_disk == raid_disks - 1)
5290 return 1;
5291 break;
5292 case ALGORITHM_LEFT_ASYMMETRIC_6:
5293 case ALGORITHM_RIGHT_ASYMMETRIC_6:
5294 case ALGORITHM_LEFT_SYMMETRIC_6:
5295 case ALGORITHM_RIGHT_SYMMETRIC_6:
5296 if (raid_disk == raid_disks - 1)
5297 return 1;
5298 }
5299 return 0;
5300 }
5301
5302 static int run(struct mddev *mddev)
5303 {
5304 struct r5conf *conf;
5305 int working_disks = 0;
5306 int dirty_parity_disks = 0;
5307 struct md_rdev *rdev;
5308 sector_t reshape_offset = 0;
5309 int i;
5310 long long min_offset_diff = 0;
5311 int first = 1;
5312
5313 if (mddev->recovery_cp != MaxSector)
5314 printk(KERN_NOTICE "md/raid:%s: not clean"
5315 " -- starting background reconstruction\n",
5316 mdname(mddev));
5317
5318 rdev_for_each(rdev, mddev) {
5319 long long diff;
5320 if (rdev->raid_disk < 0)
5321 continue;
5322 diff = (rdev->new_data_offset - rdev->data_offset);
5323 if (first) {
5324 min_offset_diff = diff;
5325 first = 0;
5326 } else if (mddev->reshape_backwards &&
5327 diff < min_offset_diff)
5328 min_offset_diff = diff;
5329 else if (!mddev->reshape_backwards &&
5330 diff > min_offset_diff)
5331 min_offset_diff = diff;
5332 }
5333
5334 if (mddev->reshape_position != MaxSector) {
5335 /* Check that we can continue the reshape.
5336 * Difficulties arise if the stripe we would write to
5337 * next is at or after the stripe we would read from next.
5338 * For a reshape that changes the number of devices, this
5339 * is only possible for a very short time, and mdadm makes
5340 * sure that time appears to have past before assembling
5341 * the array. So we fail if that time hasn't passed.
5342 * For a reshape that keeps the number of devices the same
5343 * mdadm must be monitoring the reshape can keeping the
5344 * critical areas read-only and backed up. It will start
5345 * the array in read-only mode, so we check for that.
5346 */
5347 sector_t here_new, here_old;
5348 int old_disks;
5349 int max_degraded = (mddev->level == 6 ? 2 : 1);
5350
5351 if (mddev->new_level != mddev->level) {
5352 printk(KERN_ERR "md/raid:%s: unsupported reshape "
5353 "required - aborting.\n",
5354 mdname(mddev));
5355 return -EINVAL;
5356 }
5357 old_disks = mddev->raid_disks - mddev->delta_disks;
5358 /* reshape_position must be on a new-stripe boundary, and one
5359 * further up in new geometry must map after here in old
5360 * geometry.
5361 */
5362 here_new = mddev->reshape_position;
5363 if (sector_div(here_new, mddev->new_chunk_sectors *
5364 (mddev->raid_disks - max_degraded))) {
5365 printk(KERN_ERR "md/raid:%s: reshape_position not "
5366 "on a stripe boundary\n", mdname(mddev));
5367 return -EINVAL;
5368 }
5369 reshape_offset = here_new * mddev->new_chunk_sectors;
5370 /* here_new is the stripe we will write to */
5371 here_old = mddev->reshape_position;
5372 sector_div(here_old, mddev->chunk_sectors *
5373 (old_disks-max_degraded));
5374 /* here_old is the first stripe that we might need to read
5375 * from */
5376 if (mddev->delta_disks == 0) {
5377 if ((here_new * mddev->new_chunk_sectors !=
5378 here_old * mddev->chunk_sectors)) {
5379 printk(KERN_ERR "md/raid:%s: reshape position is"
5380 " confused - aborting\n", mdname(mddev));
5381 return -EINVAL;
5382 }
5383 /* We cannot be sure it is safe to start an in-place
5384 * reshape. It is only safe if user-space is monitoring
5385 * and taking constant backups.
5386 * mdadm always starts a situation like this in
5387 * readonly mode so it can take control before
5388 * allowing any writes. So just check for that.
5389 */
5390 if (abs(min_offset_diff) >= mddev->chunk_sectors &&
5391 abs(min_offset_diff) >= mddev->new_chunk_sectors)
5392 /* not really in-place - so OK */;
5393 else if (mddev->ro == 0) {
5394 printk(KERN_ERR "md/raid:%s: in-place reshape "
5395 "must be started in read-only mode "
5396 "- aborting\n",
5397 mdname(mddev));
5398 return -EINVAL;
5399 }
5400 } else if (mddev->reshape_backwards
5401 ? (here_new * mddev->new_chunk_sectors + min_offset_diff <=
5402 here_old * mddev->chunk_sectors)
5403 : (here_new * mddev->new_chunk_sectors >=
5404 here_old * mddev->chunk_sectors + (-min_offset_diff))) {
5405 /* Reading from the same stripe as writing to - bad */
5406 printk(KERN_ERR "md/raid:%s: reshape_position too early for "
5407 "auto-recovery - aborting.\n",
5408 mdname(mddev));
5409 return -EINVAL;
5410 }
5411 printk(KERN_INFO "md/raid:%s: reshape will continue\n",
5412 mdname(mddev));
5413 /* OK, we should be able to continue; */
5414 } else {
5415 BUG_ON(mddev->level != mddev->new_level);
5416 BUG_ON(mddev->layout != mddev->new_layout);
5417 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
5418 BUG_ON(mddev->delta_disks != 0);
5419 }
5420
5421 if (mddev->private == NULL)
5422 conf = setup_conf(mddev);
5423 else
5424 conf = mddev->private;
5425
5426 if (IS_ERR(conf))
5427 return PTR_ERR(conf);
5428
5429 conf->min_offset_diff = min_offset_diff;
5430 mddev->thread = conf->thread;
5431 conf->thread = NULL;
5432 mddev->private = conf;
5433
5434 for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
5435 i++) {
5436 rdev = conf->disks[i].rdev;
5437 if (!rdev && conf->disks[i].replacement) {
5438 /* The replacement is all we have yet */
5439 rdev = conf->disks[i].replacement;
5440 conf->disks[i].replacement = NULL;
5441 clear_bit(Replacement, &rdev->flags);
5442 conf->disks[i].rdev = rdev;
5443 }
5444 if (!rdev)
5445 continue;
5446 if (conf->disks[i].replacement &&
5447 conf->reshape_progress != MaxSector) {
5448 /* replacements and reshape simply do not mix. */
5449 printk(KERN_ERR "md: cannot handle concurrent "
5450 "replacement and reshape.\n");
5451 goto abort;
5452 }
5453 if (test_bit(In_sync, &rdev->flags)) {
5454 working_disks++;
5455 continue;
5456 }
5457 /* This disc is not fully in-sync. However if it
5458 * just stored parity (beyond the recovery_offset),
5459 * when we don't need to be concerned about the
5460 * array being dirty.
5461 * When reshape goes 'backwards', we never have
5462 * partially completed devices, so we only need
5463 * to worry about reshape going forwards.
5464 */
5465 /* Hack because v0.91 doesn't store recovery_offset properly. */
5466 if (mddev->major_version == 0 &&
5467 mddev->minor_version > 90)
5468 rdev->recovery_offset = reshape_offset;
5469
5470 if (rdev->recovery_offset < reshape_offset) {
5471 /* We need to check old and new layout */
5472 if (!only_parity(rdev->raid_disk,
5473 conf->algorithm,
5474 conf->raid_disks,
5475 conf->max_degraded))
5476 continue;
5477 }
5478 if (!only_parity(rdev->raid_disk,
5479 conf->prev_algo,
5480 conf->previous_raid_disks,
5481 conf->max_degraded))
5482 continue;
5483 dirty_parity_disks++;
5484 }
5485
5486 /*
5487 * 0 for a fully functional array, 1 or 2 for a degraded array.
5488 */
5489 mddev->degraded = calc_degraded(conf);
5490
5491 if (has_failed(conf)) {
5492 printk(KERN_ERR "md/raid:%s: not enough operational devices"
5493 " (%d/%d failed)\n",
5494 mdname(mddev), mddev->degraded, conf->raid_disks);
5495 goto abort;
5496 }
5497
5498 /* device size must be a multiple of chunk size */
5499 mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
5500 mddev->resync_max_sectors = mddev->dev_sectors;
5501
5502 if (mddev->degraded > dirty_parity_disks &&
5503 mddev->recovery_cp != MaxSector) {
5504 if (mddev->ok_start_degraded)
5505 printk(KERN_WARNING
5506 "md/raid:%s: starting dirty degraded array"
5507 " - data corruption possible.\n",
5508 mdname(mddev));
5509 else {
5510 printk(KERN_ERR
5511 "md/raid:%s: cannot start dirty degraded array.\n",
5512 mdname(mddev));
5513 goto abort;
5514 }
5515 }
5516
5517 if (mddev->degraded == 0)
5518 printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
5519 " devices, algorithm %d\n", mdname(mddev), conf->level,
5520 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
5521 mddev->new_layout);
5522 else
5523 printk(KERN_ALERT "md/raid:%s: raid level %d active with %d"
5524 " out of %d devices, algorithm %d\n",
5525 mdname(mddev), conf->level,
5526 mddev->raid_disks - mddev->degraded,
5527 mddev->raid_disks, mddev->new_layout);
5528
5529 print_raid5_conf(conf);
5530
5531 if (conf->reshape_progress != MaxSector) {
5532 conf->reshape_safe = conf->reshape_progress;
5533 atomic_set(&conf->reshape_stripes, 0);
5534 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
5535 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
5536 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
5537 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
5538 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
5539 "reshape");
5540 }
5541
5542
5543 /* Ok, everything is just fine now */
5544 if (mddev->to_remove == &raid5_attrs_group)
5545 mddev->to_remove = NULL;
5546 else if (mddev->kobj.sd &&
5547 sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
5548 printk(KERN_WARNING
5549 "raid5: failed to create sysfs attributes for %s\n",
5550 mdname(mddev));
5551 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
5552
5553 if (mddev->queue) {
5554 int chunk_size;
5555 bool discard_supported = true;
5556 /* read-ahead size must cover two whole stripes, which
5557 * is 2 * (datadisks) * chunksize where 'n' is the
5558 * number of raid devices
5559 */
5560 int data_disks = conf->previous_raid_disks - conf->max_degraded;
5561 int stripe = data_disks *
5562 ((mddev->chunk_sectors << 9) / PAGE_SIZE);
5563 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
5564 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
5565
5566 blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
5567
5568 mddev->queue->backing_dev_info.congested_data = mddev;
5569 mddev->queue->backing_dev_info.congested_fn = raid5_congested;
5570
5571 chunk_size = mddev->chunk_sectors << 9;
5572 blk_queue_io_min(mddev->queue, chunk_size);
5573 blk_queue_io_opt(mddev->queue, chunk_size *
5574 (conf->raid_disks - conf->max_degraded));
5575 /*
5576 * We can only discard a whole stripe. It doesn't make sense to
5577 * discard data disk but write parity disk
5578 */
5579 stripe = stripe * PAGE_SIZE;
5580 /* Round up to power of 2, as discard handling
5581 * currently assumes that */
5582 while ((stripe-1) & stripe)
5583 stripe = (stripe | (stripe-1)) + 1;
5584 mddev->queue->limits.discard_alignment = stripe;
5585 mddev->queue->limits.discard_granularity = stripe;
5586 /*
5587 * unaligned part of discard request will be ignored, so can't
5588 * guarantee discard_zerors_data
5589 */
5590 mddev->queue->limits.discard_zeroes_data = 0;
5591
5592 blk_queue_max_write_same_sectors(mddev->queue, 0);
5593
5594 rdev_for_each(rdev, mddev) {
5595 disk_stack_limits(mddev->gendisk, rdev->bdev,
5596 rdev->data_offset << 9);
5597 disk_stack_limits(mddev->gendisk, rdev->bdev,
5598 rdev->new_data_offset << 9);
5599 /*
5600 * discard_zeroes_data is required, otherwise data
5601 * could be lost. Consider a scenario: discard a stripe
5602 * (the stripe could be inconsistent if
5603 * discard_zeroes_data is 0); write one disk of the
5604 * stripe (the stripe could be inconsistent again
5605 * depending on which disks are used to calculate
5606 * parity); the disk is broken; The stripe data of this
5607 * disk is lost.
5608 */
5609 if (!blk_queue_discard(bdev_get_queue(rdev->bdev)) ||
5610 !bdev_get_queue(rdev->bdev)->
5611 limits.discard_zeroes_data)
5612 discard_supported = false;
5613 }
5614
5615 if (discard_supported &&
5616 mddev->queue->limits.max_discard_sectors >= stripe &&
5617 mddev->queue->limits.discard_granularity >= stripe)
5618 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
5619 mddev->queue);
5620 else
5621 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
5622 mddev->queue);
5623 }
5624
5625 return 0;
5626 abort:
5627 md_unregister_thread(&mddev->thread);
5628 print_raid5_conf(conf);
5629 free_conf(conf);
5630 mddev->private = NULL;
5631 printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
5632 return -EIO;
5633 }
5634
5635 static int stop(struct mddev *mddev)
5636 {
5637 struct r5conf *conf = mddev->private;
5638
5639 md_unregister_thread(&mddev->thread);
5640 if (mddev->queue)
5641 mddev->queue->backing_dev_info.congested_fn = NULL;
5642 free_conf(conf);
5643 mddev->private = NULL;
5644 mddev->to_remove = &raid5_attrs_group;
5645 return 0;
5646 }
5647
5648 static void status(struct seq_file *seq, struct mddev *mddev)
5649 {
5650 struct r5conf *conf = mddev->private;
5651 int i;
5652
5653 seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
5654 mddev->chunk_sectors / 2, mddev->layout);
5655 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
5656 for (i = 0; i < conf->raid_disks; i++)
5657 seq_printf (seq, "%s",
5658 conf->disks[i].rdev &&
5659 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
5660 seq_printf (seq, "]");
5661 }
5662
5663 static void print_raid5_conf (struct r5conf *conf)
5664 {
5665 int i;
5666 struct disk_info *tmp;
5667
5668 printk(KERN_DEBUG "RAID conf printout:\n");
5669 if (!conf) {
5670 printk("(conf==NULL)\n");
5671 return;
5672 }
5673 printk(KERN_DEBUG " --- level:%d rd:%d wd:%d\n", conf->level,
5674 conf->raid_disks,
5675 conf->raid_disks - conf->mddev->degraded);
5676
5677 for (i = 0; i < conf->raid_disks; i++) {
5678 char b[BDEVNAME_SIZE];
5679 tmp = conf->disks + i;
5680 if (tmp->rdev)
5681 printk(KERN_DEBUG " disk %d, o:%d, dev:%s\n",
5682 i, !test_bit(Faulty, &tmp->rdev->flags),
5683 bdevname(tmp->rdev->bdev, b));
5684 }
5685 }
5686
5687 static int raid5_spare_active(struct mddev *mddev)
5688 {
5689 int i;
5690 struct r5conf *conf = mddev->private;
5691 struct disk_info *tmp;
5692 int count = 0;
5693 unsigned long flags;
5694
5695 for (i = 0; i < conf->raid_disks; i++) {
5696 tmp = conf->disks + i;
5697 if (tmp->replacement
5698 && tmp->replacement->recovery_offset == MaxSector
5699 && !test_bit(Faulty, &tmp->replacement->flags)
5700 && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
5701 /* Replacement has just become active. */
5702 if (!tmp->rdev
5703 || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
5704 count++;
5705 if (tmp->rdev) {
5706 /* Replaced device not technically faulty,
5707 * but we need to be sure it gets removed
5708 * and never re-added.
5709 */
5710 set_bit(Faulty, &tmp->rdev->flags);
5711 sysfs_notify_dirent_safe(
5712 tmp->rdev->sysfs_state);
5713 }
5714 sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
5715 } else if (tmp->rdev
5716 && tmp->rdev->recovery_offset == MaxSector
5717 && !test_bit(Faulty, &tmp->rdev->flags)
5718 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
5719 count++;
5720 sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
5721 }
5722 }
5723 spin_lock_irqsave(&conf->device_lock, flags);
5724 mddev->degraded = calc_degraded(conf);
5725 spin_unlock_irqrestore(&conf->device_lock, flags);
5726 print_raid5_conf(conf);
5727 return count;
5728 }
5729
5730 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
5731 {
5732 struct r5conf *conf = mddev->private;
5733 int err = 0;
5734 int number = rdev->raid_disk;
5735 struct md_rdev **rdevp;
5736 struct disk_info *p = conf->disks + number;
5737
5738 print_raid5_conf(conf);
5739 if (rdev == p->rdev)
5740 rdevp = &p->rdev;
5741 else if (rdev == p->replacement)
5742 rdevp = &p->replacement;
5743 else
5744 return 0;
5745
5746 if (number >= conf->raid_disks &&
5747 conf->reshape_progress == MaxSector)
5748 clear_bit(In_sync, &rdev->flags);
5749
5750 if (test_bit(In_sync, &rdev->flags) ||
5751 atomic_read(&rdev->nr_pending)) {
5752 err = -EBUSY;
5753 goto abort;
5754 }
5755 /* Only remove non-faulty devices if recovery
5756 * isn't possible.
5757 */
5758 if (!test_bit(Faulty, &rdev->flags) &&
5759 mddev->recovery_disabled != conf->recovery_disabled &&
5760 !has_failed(conf) &&
5761 (!p->replacement || p->replacement == rdev) &&
5762 number < conf->raid_disks) {
5763 err = -EBUSY;
5764 goto abort;
5765 }
5766 *rdevp = NULL;
5767 synchronize_rcu();
5768 if (atomic_read(&rdev->nr_pending)) {
5769 /* lost the race, try later */
5770 err = -EBUSY;
5771 *rdevp = rdev;
5772 } else if (p->replacement) {
5773 /* We must have just cleared 'rdev' */
5774 p->rdev = p->replacement;
5775 clear_bit(Replacement, &p->replacement->flags);
5776 smp_mb(); /* Make sure other CPUs may see both as identical
5777 * but will never see neither - if they are careful
5778 */
5779 p->replacement = NULL;
5780 clear_bit(WantReplacement, &rdev->flags);
5781 } else
5782 /* We might have just removed the Replacement as faulty-
5783 * clear the bit just in case
5784 */
5785 clear_bit(WantReplacement, &rdev->flags);
5786 abort:
5787
5788 print_raid5_conf(conf);
5789 return err;
5790 }
5791
5792 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
5793 {
5794 struct r5conf *conf = mddev->private;
5795 int err = -EEXIST;
5796 int disk;
5797 struct disk_info *p;
5798 int first = 0;
5799 int last = conf->raid_disks - 1;
5800
5801 if (mddev->recovery_disabled == conf->recovery_disabled)
5802 return -EBUSY;
5803
5804 if (rdev->saved_raid_disk < 0 && has_failed(conf))
5805 /* no point adding a device */
5806 return -EINVAL;
5807
5808 if (rdev->raid_disk >= 0)
5809 first = last = rdev->raid_disk;
5810
5811 /*
5812 * find the disk ... but prefer rdev->saved_raid_disk
5813 * if possible.
5814 */
5815 if (rdev->saved_raid_disk >= 0 &&
5816 rdev->saved_raid_disk >= first &&
5817 conf->disks[rdev->saved_raid_disk].rdev == NULL)
5818 first = rdev->saved_raid_disk;
5819
5820 for (disk = first; disk <= last; disk++) {
5821 p = conf->disks + disk;
5822 if (p->rdev == NULL) {
5823 clear_bit(In_sync, &rdev->flags);
5824 rdev->raid_disk = disk;
5825 err = 0;
5826 if (rdev->saved_raid_disk != disk)
5827 conf->fullsync = 1;
5828 rcu_assign_pointer(p->rdev, rdev);
5829 goto out;
5830 }
5831 }
5832 for (disk = first; disk <= last; disk++) {
5833 p = conf->disks + disk;
5834 if (test_bit(WantReplacement, &p->rdev->flags) &&
5835 p->replacement == NULL) {
5836 clear_bit(In_sync, &rdev->flags);
5837 set_bit(Replacement, &rdev->flags);
5838 rdev->raid_disk = disk;
5839 err = 0;
5840 conf->fullsync = 1;
5841 rcu_assign_pointer(p->replacement, rdev);
5842 break;
5843 }
5844 }
5845 out:
5846 print_raid5_conf(conf);
5847 return err;
5848 }
5849
5850 static int raid5_resize(struct mddev *mddev, sector_t sectors)
5851 {
5852 /* no resync is happening, and there is enough space
5853 * on all devices, so we can resize.
5854 * We need to make sure resync covers any new space.
5855 * If the array is shrinking we should possibly wait until
5856 * any io in the removed space completes, but it hardly seems
5857 * worth it.
5858 */
5859 sector_t newsize;
5860 sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5861 newsize = raid5_size(mddev, sectors, mddev->raid_disks);
5862 if (mddev->external_size &&
5863 mddev->array_sectors > newsize)
5864 return -EINVAL;
5865 if (mddev->bitmap) {
5866 int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
5867 if (ret)
5868 return ret;
5869 }
5870 md_set_array_sectors(mddev, newsize);
5871 set_capacity(mddev->gendisk, mddev->array_sectors);
5872 revalidate_disk(mddev->gendisk);
5873 if (sectors > mddev->dev_sectors &&
5874 mddev->recovery_cp > mddev->dev_sectors) {
5875 mddev->recovery_cp = mddev->dev_sectors;
5876 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5877 }
5878 mddev->dev_sectors = sectors;
5879 mddev->resync_max_sectors = sectors;
5880 return 0;
5881 }
5882
5883 static int check_stripe_cache(struct mddev *mddev)
5884 {
5885 /* Can only proceed if there are plenty of stripe_heads.
5886 * We need a minimum of one full stripe,, and for sensible progress
5887 * it is best to have about 4 times that.
5888 * If we require 4 times, then the default 256 4K stripe_heads will
5889 * allow for chunk sizes up to 256K, which is probably OK.
5890 * If the chunk size is greater, user-space should request more
5891 * stripe_heads first.
5892 */
5893 struct r5conf *conf = mddev->private;
5894 if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
5895 > conf->max_nr_stripes ||
5896 ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
5897 > conf->max_nr_stripes) {
5898 printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes. Needed %lu\n",
5899 mdname(mddev),
5900 ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
5901 / STRIPE_SIZE)*4);
5902 return 0;
5903 }
5904 return 1;
5905 }
5906
5907 static int check_reshape(struct mddev *mddev)
5908 {
5909 struct r5conf *conf = mddev->private;
5910
5911 if (mddev->delta_disks == 0 &&
5912 mddev->new_layout == mddev->layout &&
5913 mddev->new_chunk_sectors == mddev->chunk_sectors)
5914 return 0; /* nothing to do */
5915 if (has_failed(conf))
5916 return -EINVAL;
5917 if (mddev->delta_disks < 0) {
5918 /* We might be able to shrink, but the devices must
5919 * be made bigger first.
5920 * For raid6, 4 is the minimum size.
5921 * Otherwise 2 is the minimum
5922 */
5923 int min = 2;
5924 if (mddev->level == 6)
5925 min = 4;
5926 if (mddev->raid_disks + mddev->delta_disks < min)
5927 return -EINVAL;
5928 }
5929
5930 if (!check_stripe_cache(mddev))
5931 return -ENOSPC;
5932
5933 return resize_stripes(conf, (conf->previous_raid_disks
5934 + mddev->delta_disks));
5935 }
5936
5937 static int raid5_start_reshape(struct mddev *mddev)
5938 {
5939 struct r5conf *conf = mddev->private;
5940 struct md_rdev *rdev;
5941 int spares = 0;
5942 unsigned long flags;
5943
5944 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5945 return -EBUSY;
5946
5947 if (!check_stripe_cache(mddev))
5948 return -ENOSPC;
5949
5950 if (has_failed(conf))
5951 return -EINVAL;
5952
5953 rdev_for_each(rdev, mddev) {
5954 if (!test_bit(In_sync, &rdev->flags)
5955 && !test_bit(Faulty, &rdev->flags))
5956 spares++;
5957 }
5958
5959 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
5960 /* Not enough devices even to make a degraded array
5961 * of that size
5962 */
5963 return -EINVAL;
5964
5965 /* Refuse to reduce size of the array. Any reductions in
5966 * array size must be through explicit setting of array_size
5967 * attribute.
5968 */
5969 if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
5970 < mddev->array_sectors) {
5971 printk(KERN_ERR "md/raid:%s: array size must be reduced "
5972 "before number of disks\n", mdname(mddev));
5973 return -EINVAL;
5974 }
5975
5976 atomic_set(&conf->reshape_stripes, 0);
5977 spin_lock_irq(&conf->device_lock);
5978 conf->previous_raid_disks = conf->raid_disks;
5979 conf->raid_disks += mddev->delta_disks;
5980 conf->prev_chunk_sectors = conf->chunk_sectors;
5981 conf->chunk_sectors = mddev->new_chunk_sectors;
5982 conf->prev_algo = conf->algorithm;
5983 conf->algorithm = mddev->new_layout;
5984 conf->generation++;
5985 /* Code that selects data_offset needs to see the generation update
5986 * if reshape_progress has been set - so a memory barrier needed.
5987 */
5988 smp_mb();
5989 if (mddev->reshape_backwards)
5990 conf->reshape_progress = raid5_size(mddev, 0, 0);
5991 else
5992 conf->reshape_progress = 0;
5993 conf->reshape_safe = conf->reshape_progress;
5994 spin_unlock_irq(&conf->device_lock);
5995
5996 /* Add some new drives, as many as will fit.
5997 * We know there are enough to make the newly sized array work.
5998 * Don't add devices if we are reducing the number of
5999 * devices in the array. This is because it is not possible
6000 * to correctly record the "partially reconstructed" state of
6001 * such devices during the reshape and confusion could result.
6002 */
6003 if (mddev->delta_disks >= 0) {
6004 rdev_for_each(rdev, mddev)
6005 if (rdev->raid_disk < 0 &&
6006 !test_bit(Faulty, &rdev->flags)) {
6007 if (raid5_add_disk(mddev, rdev) == 0) {
6008 if (rdev->raid_disk
6009 >= conf->previous_raid_disks)
6010 set_bit(In_sync, &rdev->flags);
6011 else
6012 rdev->recovery_offset = 0;
6013
6014 if (sysfs_link_rdev(mddev, rdev))
6015 /* Failure here is OK */;
6016 }
6017 } else if (rdev->raid_disk >= conf->previous_raid_disks
6018 && !test_bit(Faulty, &rdev->flags)) {
6019 /* This is a spare that was manually added */
6020 set_bit(In_sync, &rdev->flags);
6021 }
6022
6023 /* When a reshape changes the number of devices,
6024 * ->degraded is measured against the larger of the
6025 * pre and post number of devices.
6026 */
6027 spin_lock_irqsave(&conf->device_lock, flags);
6028 mddev->degraded = calc_degraded(conf);
6029 spin_unlock_irqrestore(&conf->device_lock, flags);
6030 }
6031 mddev->raid_disks = conf->raid_disks;
6032 mddev->reshape_position = conf->reshape_progress;
6033 set_bit(MD_CHANGE_DEVS, &mddev->flags);
6034
6035 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
6036 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
6037 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
6038 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
6039 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
6040 "reshape");
6041 if (!mddev->sync_thread) {
6042 mddev->recovery = 0;
6043 spin_lock_irq(&conf->device_lock);
6044 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
6045 rdev_for_each(rdev, mddev)
6046 rdev->new_data_offset = rdev->data_offset;
6047 smp_wmb();
6048 conf->reshape_progress = MaxSector;
6049 mddev->reshape_position = MaxSector;
6050 spin_unlock_irq(&conf->device_lock);
6051 return -EAGAIN;
6052 }
6053 conf->reshape_checkpoint = jiffies;
6054 md_wakeup_thread(mddev->sync_thread);
6055 md_new_event(mddev);
6056 return 0;
6057 }
6058
6059 /* This is called from the reshape thread and should make any
6060 * changes needed in 'conf'
6061 */
6062 static void end_reshape(struct r5conf *conf)
6063 {
6064
6065 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
6066 struct md_rdev *rdev;
6067
6068 spin_lock_irq(&conf->device_lock);
6069 conf->previous_raid_disks = conf->raid_disks;
6070 rdev_for_each(rdev, conf->mddev)
6071 rdev->data_offset = rdev->new_data_offset;
6072 smp_wmb();
6073 conf->reshape_progress = MaxSector;
6074 spin_unlock_irq(&conf->device_lock);
6075 wake_up(&conf->wait_for_overlap);
6076
6077 /* read-ahead size must cover two whole stripes, which is
6078 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
6079 */
6080 if (conf->mddev->queue) {
6081 int data_disks = conf->raid_disks - conf->max_degraded;
6082 int stripe = data_disks * ((conf->chunk_sectors << 9)
6083 / PAGE_SIZE);
6084 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
6085 conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
6086 }
6087 }
6088 }
6089
6090 /* This is called from the raid5d thread with mddev_lock held.
6091 * It makes config changes to the device.
6092 */
6093 static void raid5_finish_reshape(struct mddev *mddev)
6094 {
6095 struct r5conf *conf = mddev->private;
6096
6097 if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
6098
6099 if (mddev->delta_disks > 0) {
6100 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
6101 set_capacity(mddev->gendisk, mddev->array_sectors);
6102 revalidate_disk(mddev->gendisk);
6103 } else {
6104 int d;
6105 spin_lock_irq(&conf->device_lock);
6106 mddev->degraded = calc_degraded(conf);
6107 spin_unlock_irq(&conf->device_lock);
6108 for (d = conf->raid_disks ;
6109 d < conf->raid_disks - mddev->delta_disks;
6110 d++) {
6111 struct md_rdev *rdev = conf->disks[d].rdev;
6112 if (rdev)
6113 clear_bit(In_sync, &rdev->flags);
6114 rdev = conf->disks[d].replacement;
6115 if (rdev)
6116 clear_bit(In_sync, &rdev->flags);
6117 }
6118 }
6119 mddev->layout = conf->algorithm;
6120 mddev->chunk_sectors = conf->chunk_sectors;
6121 mddev->reshape_position = MaxSector;
6122 mddev->delta_disks = 0;
6123 mddev->reshape_backwards = 0;
6124 }
6125 }
6126
6127 static void raid5_quiesce(struct mddev *mddev, int state)
6128 {
6129 struct r5conf *conf = mddev->private;
6130
6131 switch(state) {
6132 case 2: /* resume for a suspend */
6133 wake_up(&conf->wait_for_overlap);
6134 break;
6135
6136 case 1: /* stop all writes */
6137 spin_lock_irq(&conf->device_lock);
6138 /* '2' tells resync/reshape to pause so that all
6139 * active stripes can drain
6140 */
6141 conf->quiesce = 2;
6142 wait_event_lock_irq(conf->wait_for_stripe,
6143 atomic_read(&conf->active_stripes) == 0 &&
6144 atomic_read(&conf->active_aligned_reads) == 0,
6145 conf->device_lock);
6146 conf->quiesce = 1;
6147 spin_unlock_irq(&conf->device_lock);
6148 /* allow reshape to continue */
6149 wake_up(&conf->wait_for_overlap);
6150 break;
6151
6152 case 0: /* re-enable writes */
6153 spin_lock_irq(&conf->device_lock);
6154 conf->quiesce = 0;
6155 wake_up(&conf->wait_for_stripe);
6156 wake_up(&conf->wait_for_overlap);
6157 spin_unlock_irq(&conf->device_lock);
6158 break;
6159 }
6160 }
6161
6162
6163 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
6164 {
6165 struct r0conf *raid0_conf = mddev->private;
6166 sector_t sectors;
6167
6168 /* for raid0 takeover only one zone is supported */
6169 if (raid0_conf->nr_strip_zones > 1) {
6170 printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
6171 mdname(mddev));
6172 return ERR_PTR(-EINVAL);
6173 }
6174
6175 sectors = raid0_conf->strip_zone[0].zone_end;
6176 sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
6177 mddev->dev_sectors = sectors;
6178 mddev->new_level = level;
6179 mddev->new_layout = ALGORITHM_PARITY_N;
6180 mddev->new_chunk_sectors = mddev->chunk_sectors;
6181 mddev->raid_disks += 1;
6182 mddev->delta_disks = 1;
6183 /* make sure it will be not marked as dirty */
6184 mddev->recovery_cp = MaxSector;
6185
6186 return setup_conf(mddev);
6187 }
6188
6189
6190 static void *raid5_takeover_raid1(struct mddev *mddev)
6191 {
6192 int chunksect;
6193
6194 if (mddev->raid_disks != 2 ||
6195 mddev->degraded > 1)
6196 return ERR_PTR(-EINVAL);
6197
6198 /* Should check if there are write-behind devices? */
6199
6200 chunksect = 64*2; /* 64K by default */
6201
6202 /* The array must be an exact multiple of chunksize */
6203 while (chunksect && (mddev->array_sectors & (chunksect-1)))
6204 chunksect >>= 1;
6205
6206 if ((chunksect<<9) < STRIPE_SIZE)
6207 /* array size does not allow a suitable chunk size */
6208 return ERR_PTR(-EINVAL);
6209
6210 mddev->new_level = 5;
6211 mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
6212 mddev->new_chunk_sectors = chunksect;
6213
6214 return setup_conf(mddev);
6215 }
6216
6217 static void *raid5_takeover_raid6(struct mddev *mddev)
6218 {
6219 int new_layout;
6220
6221 switch (mddev->layout) {
6222 case ALGORITHM_LEFT_ASYMMETRIC_6:
6223 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
6224 break;
6225 case ALGORITHM_RIGHT_ASYMMETRIC_6:
6226 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
6227 break;
6228 case ALGORITHM_LEFT_SYMMETRIC_6:
6229 new_layout = ALGORITHM_LEFT_SYMMETRIC;
6230 break;
6231 case ALGORITHM_RIGHT_SYMMETRIC_6:
6232 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
6233 break;
6234 case ALGORITHM_PARITY_0_6:
6235 new_layout = ALGORITHM_PARITY_0;
6236 break;
6237 case ALGORITHM_PARITY_N:
6238 new_layout = ALGORITHM_PARITY_N;
6239 break;
6240 default:
6241 return ERR_PTR(-EINVAL);
6242 }
6243 mddev->new_level = 5;
6244 mddev->new_layout = new_layout;
6245 mddev->delta_disks = -1;
6246 mddev->raid_disks -= 1;
6247 return setup_conf(mddev);
6248 }
6249
6250
6251 static int raid5_check_reshape(struct mddev *mddev)
6252 {
6253 /* For a 2-drive array, the layout and chunk size can be changed
6254 * immediately as not restriping is needed.
6255 * For larger arrays we record the new value - after validation
6256 * to be used by a reshape pass.
6257 */
6258 struct r5conf *conf = mddev->private;
6259 int new_chunk = mddev->new_chunk_sectors;
6260
6261 if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
6262 return -EINVAL;
6263 if (new_chunk > 0) {
6264 if (!is_power_of_2(new_chunk))
6265 return -EINVAL;
6266 if (new_chunk < (PAGE_SIZE>>9))
6267 return -EINVAL;
6268 if (mddev->array_sectors & (new_chunk-1))
6269 /* not factor of array size */
6270 return -EINVAL;
6271 }
6272
6273 /* They look valid */
6274
6275 if (mddev->raid_disks == 2) {
6276 /* can make the change immediately */
6277 if (mddev->new_layout >= 0) {
6278 conf->algorithm = mddev->new_layout;
6279 mddev->layout = mddev->new_layout;
6280 }
6281 if (new_chunk > 0) {
6282 conf->chunk_sectors = new_chunk ;
6283 mddev->chunk_sectors = new_chunk;
6284 }
6285 set_bit(MD_CHANGE_DEVS, &mddev->flags);
6286 md_wakeup_thread(mddev->thread);
6287 }
6288 return check_reshape(mddev);
6289 }
6290
6291 static int raid6_check_reshape(struct mddev *mddev)
6292 {
6293 int new_chunk = mddev->new_chunk_sectors;
6294
6295 if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
6296 return -EINVAL;
6297 if (new_chunk > 0) {
6298 if (!is_power_of_2(new_chunk))
6299 return -EINVAL;
6300 if (new_chunk < (PAGE_SIZE >> 9))
6301 return -EINVAL;
6302 if (mddev->array_sectors & (new_chunk-1))
6303 /* not factor of array size */
6304 return -EINVAL;
6305 }
6306
6307 /* They look valid */
6308 return check_reshape(mddev);
6309 }
6310
6311 static void *raid5_takeover(struct mddev *mddev)
6312 {
6313 /* raid5 can take over:
6314 * raid0 - if there is only one strip zone - make it a raid4 layout
6315 * raid1 - if there are two drives. We need to know the chunk size
6316 * raid4 - trivial - just use a raid4 layout.
6317 * raid6 - Providing it is a *_6 layout
6318 */
6319 if (mddev->level == 0)
6320 return raid45_takeover_raid0(mddev, 5);
6321 if (mddev->level == 1)
6322 return raid5_takeover_raid1(mddev);
6323 if (mddev->level == 4) {
6324 mddev->new_layout = ALGORITHM_PARITY_N;
6325 mddev->new_level = 5;
6326 return setup_conf(mddev);
6327 }
6328 if (mddev->level == 6)
6329 return raid5_takeover_raid6(mddev);
6330
6331 return ERR_PTR(-EINVAL);
6332 }
6333
6334 static void *raid4_takeover(struct mddev *mddev)
6335 {
6336 /* raid4 can take over:
6337 * raid0 - if there is only one strip zone
6338 * raid5 - if layout is right
6339 */
6340 if (mddev->level == 0)
6341 return raid45_takeover_raid0(mddev, 4);
6342 if (mddev->level == 5 &&
6343 mddev->layout == ALGORITHM_PARITY_N) {
6344 mddev->new_layout = 0;
6345 mddev->new_level = 4;
6346 return setup_conf(mddev);
6347 }
6348 return ERR_PTR(-EINVAL);
6349 }
6350
6351 static struct md_personality raid5_personality;
6352
6353 static void *raid6_takeover(struct mddev *mddev)
6354 {
6355 /* Currently can only take over a raid5. We map the
6356 * personality to an equivalent raid6 personality
6357 * with the Q block at the end.
6358 */
6359 int new_layout;
6360
6361 if (mddev->pers != &raid5_personality)
6362 return ERR_PTR(-EINVAL);
6363 if (mddev->degraded > 1)
6364 return ERR_PTR(-EINVAL);
6365 if (mddev->raid_disks > 253)
6366 return ERR_PTR(-EINVAL);
6367 if (mddev->raid_disks < 3)
6368 return ERR_PTR(-EINVAL);
6369
6370 switch (mddev->layout) {
6371 case ALGORITHM_LEFT_ASYMMETRIC:
6372 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
6373 break;
6374 case ALGORITHM_RIGHT_ASYMMETRIC:
6375 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
6376 break;
6377 case ALGORITHM_LEFT_SYMMETRIC:
6378 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
6379 break;
6380 case ALGORITHM_RIGHT_SYMMETRIC:
6381 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
6382 break;
6383 case ALGORITHM_PARITY_0:
6384 new_layout = ALGORITHM_PARITY_0_6;
6385 break;
6386 case ALGORITHM_PARITY_N:
6387 new_layout = ALGORITHM_PARITY_N;
6388 break;
6389 default:
6390 return ERR_PTR(-EINVAL);
6391 }
6392 mddev->new_level = 6;
6393 mddev->new_layout = new_layout;
6394 mddev->delta_disks = 1;
6395 mddev->raid_disks += 1;
6396 return setup_conf(mddev);
6397 }
6398
6399
6400 static struct md_personality raid6_personality =
6401 {
6402 .name = "raid6",
6403 .level = 6,
6404 .owner = THIS_MODULE,
6405 .make_request = make_request,
6406 .run = run,
6407 .stop = stop,
6408 .status = status,
6409 .error_handler = error,
6410 .hot_add_disk = raid5_add_disk,
6411 .hot_remove_disk= raid5_remove_disk,
6412 .spare_active = raid5_spare_active,
6413 .sync_request = sync_request,
6414 .resize = raid5_resize,
6415 .size = raid5_size,
6416 .check_reshape = raid6_check_reshape,
6417 .start_reshape = raid5_start_reshape,
6418 .finish_reshape = raid5_finish_reshape,
6419 .quiesce = raid5_quiesce,
6420 .takeover = raid6_takeover,
6421 };
6422 static struct md_personality raid5_personality =
6423 {
6424 .name = "raid5",
6425 .level = 5,
6426 .owner = THIS_MODULE,
6427 .make_request = make_request,
6428 .run = run,
6429 .stop = stop,
6430 .status = status,
6431 .error_handler = error,
6432 .hot_add_disk = raid5_add_disk,
6433 .hot_remove_disk= raid5_remove_disk,
6434 .spare_active = raid5_spare_active,
6435 .sync_request = sync_request,
6436 .resize = raid5_resize,
6437 .size = raid5_size,
6438 .check_reshape = raid5_check_reshape,
6439 .start_reshape = raid5_start_reshape,
6440 .finish_reshape = raid5_finish_reshape,
6441 .quiesce = raid5_quiesce,
6442 .takeover = raid5_takeover,
6443 };
6444
6445 static struct md_personality raid4_personality =
6446 {
6447 .name = "raid4",
6448 .level = 4,
6449 .owner = THIS_MODULE,
6450 .make_request = make_request,
6451 .run = run,
6452 .stop = stop,
6453 .status = status,
6454 .error_handler = error,
6455 .hot_add_disk = raid5_add_disk,
6456 .hot_remove_disk= raid5_remove_disk,
6457 .spare_active = raid5_spare_active,
6458 .sync_request = sync_request,
6459 .resize = raid5_resize,
6460 .size = raid5_size,
6461 .check_reshape = raid5_check_reshape,
6462 .start_reshape = raid5_start_reshape,
6463 .finish_reshape = raid5_finish_reshape,
6464 .quiesce = raid5_quiesce,
6465 .takeover = raid4_takeover,
6466 };
6467
6468 static int __init raid5_init(void)
6469 {
6470 register_md_personality(&raid6_personality);
6471 register_md_personality(&raid5_personality);
6472 register_md_personality(&raid4_personality);
6473 return 0;
6474 }
6475
6476 static void raid5_exit(void)
6477 {
6478 unregister_md_personality(&raid6_personality);
6479 unregister_md_personality(&raid5_personality);
6480 unregister_md_personality(&raid4_personality);
6481 }
6482
6483 module_init(raid5_init);
6484 module_exit(raid5_exit);
6485 MODULE_LICENSE("GPL");
6486 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
6487 MODULE_ALIAS("md-personality-4"); /* RAID5 */
6488 MODULE_ALIAS("md-raid5");
6489 MODULE_ALIAS("md-raid4");
6490 MODULE_ALIAS("md-level-5");
6491 MODULE_ALIAS("md-level-4");
6492 MODULE_ALIAS("md-personality-8"); /* RAID6 */
6493 MODULE_ALIAS("md-raid6");
6494 MODULE_ALIAS("md-level-6");
6495
6496 /* This used to be two separate modules, they were: */
6497 MODULE_ALIAS("raid5");
6498 MODULE_ALIAS("raid6");
kernel source for telekom puls (alcatel/mediatek)