2 * raid1.c : Multiple Devices driver for Linux
4 * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
6 * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
8 * RAID-1 management functions.
10 * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
12 * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
13 * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
15 * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
16 * bitmapped intelligence in resync:
18 * - bitmap marked during normal i/o
19 * - bitmap used to skip nondirty blocks during sync
21 * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
22 * - persistent bitmap code
24 * This program is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; either version 2, or (at your option)
29 * You should have received a copy of the GNU General Public License
30 * (for example /usr/src/linux/COPYING); if not, write to the Free
31 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
34 #include <linux/slab.h>
35 #include <linux/delay.h>
36 #include <linux/blkdev.h>
37 #include <linux/module.h>
38 #include <linux/seq_file.h>
39 #include <linux/ratelimit.h>
45 * Number of guaranteed r1bios in case of extreme VM load:
47 #define NR_RAID1_BIOS 256
49 /* when we get a read error on a read-only array, we redirect to another
50 * device without failing the first device, or trying to over-write to
51 * correct the read error. To keep track of bad blocks on a per-bio
52 * level, we store IO_BLOCKED in the appropriate 'bios' pointer
54 #define IO_BLOCKED ((struct bio *)1)
55 /* When we successfully write to a known bad-block, we need to remove the
56 * bad-block marking which must be done from process context. So we record
57 * the success by setting devs[n].bio to IO_MADE_GOOD
59 #define IO_MADE_GOOD ((struct bio *)2)
61 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
63 /* When there are this many requests queue to be written by
64 * the raid1 thread, we become 'congested' to provide back-pressure
67 static int max_queued_requests = 1024;
69 static void allow_barrier(struct r1conf *conf, sector_t start_next_window,
71 static void lower_barrier(struct r1conf *conf);
73 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
75 struct pool_info *pi = data;
76 int size = offsetof(struct r1bio, bios[pi->raid_disks]);
78 /* allocate a r1bio with room for raid_disks entries in the bios array */
79 return kzalloc(size, gfp_flags);
82 static void r1bio_pool_free(void *r1_bio, void *data)
87 #define RESYNC_BLOCK_SIZE (64*1024)
88 #define RESYNC_DEPTH 32
89 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
90 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
91 #define RESYNC_WINDOW (RESYNC_BLOCK_SIZE * RESYNC_DEPTH)
92 #define RESYNC_WINDOW_SECTORS (RESYNC_WINDOW >> 9)
93 #define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
94 #define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
95 #define NEXT_NORMALIO_DISTANCE (3 * RESYNC_WINDOW_SECTORS)
97 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
99 struct pool_info *pi = data;
100 struct r1bio *r1_bio;
105 r1_bio = r1bio_pool_alloc(gfp_flags, pi);
110 * Allocate bios : 1 for reading, n-1 for writing
112 for (j = pi->raid_disks ; j-- ; ) {
113 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
116 r1_bio->bios[j] = bio;
119 * Allocate RESYNC_PAGES data pages and attach them to
121 * If this is a user-requested check/repair, allocate
122 * RESYNC_PAGES for each bio.
124 if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
125 need_pages = pi->raid_disks;
128 for (j = 0; j < need_pages; j++) {
129 bio = r1_bio->bios[j];
130 bio->bi_vcnt = RESYNC_PAGES;
132 if (bio_alloc_pages(bio, gfp_flags))
135 /* If not user-requests, copy the page pointers to all bios */
136 if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
137 for (i=0; i<RESYNC_PAGES ; i++)
138 for (j=1; j<pi->raid_disks; j++)
139 r1_bio->bios[j]->bi_io_vec[i].bv_page =
140 r1_bio->bios[0]->bi_io_vec[i].bv_page;
143 r1_bio->master_bio = NULL;
149 bio_free_pages(r1_bio->bios[j]);
152 while (++j < pi->raid_disks)
153 bio_put(r1_bio->bios[j]);
154 r1bio_pool_free(r1_bio, data);
158 static void r1buf_pool_free(void *__r1_bio, void *data)
160 struct pool_info *pi = data;
162 struct r1bio *r1bio = __r1_bio;
164 for (i = 0; i < RESYNC_PAGES; i++)
165 for (j = pi->raid_disks; j-- ;) {
167 r1bio->bios[j]->bi_io_vec[i].bv_page !=
168 r1bio->bios[0]->bi_io_vec[i].bv_page)
169 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
171 for (i=0 ; i < pi->raid_disks; i++)
172 bio_put(r1bio->bios[i]);
174 r1bio_pool_free(r1bio, data);
177 static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
181 for (i = 0; i < conf->raid_disks * 2; i++) {
182 struct bio **bio = r1_bio->bios + i;
183 if (!BIO_SPECIAL(*bio))
189 static void free_r1bio(struct r1bio *r1_bio)
191 struct r1conf *conf = r1_bio->mddev->private;
193 put_all_bios(conf, r1_bio);
194 mempool_free(r1_bio, conf->r1bio_pool);
197 static void put_buf(struct r1bio *r1_bio)
199 struct r1conf *conf = r1_bio->mddev->private;
202 for (i = 0; i < conf->raid_disks * 2; i++) {
203 struct bio *bio = r1_bio->bios[i];
205 rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
208 mempool_free(r1_bio, conf->r1buf_pool);
213 static void reschedule_retry(struct r1bio *r1_bio)
216 struct mddev *mddev = r1_bio->mddev;
217 struct r1conf *conf = mddev->private;
219 spin_lock_irqsave(&conf->device_lock, flags);
220 list_add(&r1_bio->retry_list, &conf->retry_list);
222 spin_unlock_irqrestore(&conf->device_lock, flags);
224 wake_up(&conf->wait_barrier);
225 md_wakeup_thread(mddev->thread);
229 * raid_end_bio_io() is called when we have finished servicing a mirrored
230 * operation and are ready to return a success/failure code to the buffer
233 static void call_bio_endio(struct r1bio *r1_bio)
235 struct bio *bio = r1_bio->master_bio;
237 struct r1conf *conf = r1_bio->mddev->private;
238 sector_t start_next_window = r1_bio->start_next_window;
239 sector_t bi_sector = bio->bi_iter.bi_sector;
241 if (bio->bi_phys_segments) {
243 spin_lock_irqsave(&conf->device_lock, flags);
244 bio->bi_phys_segments--;
245 done = (bio->bi_phys_segments == 0);
246 spin_unlock_irqrestore(&conf->device_lock, flags);
248 * make_request() might be waiting for
249 * bi_phys_segments to decrease
251 wake_up(&conf->wait_barrier);
255 if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
256 bio->bi_error = -EIO;
261 * Wake up any possible resync thread that waits for the device
264 allow_barrier(conf, start_next_window, bi_sector);
268 static void raid_end_bio_io(struct r1bio *r1_bio)
270 struct bio *bio = r1_bio->master_bio;
272 /* if nobody has done the final endio yet, do it now */
273 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
274 pr_debug("raid1: sync end %s on sectors %llu-%llu\n",
275 (bio_data_dir(bio) == WRITE) ? "write" : "read",
276 (unsigned long long) bio->bi_iter.bi_sector,
277 (unsigned long long) bio_end_sector(bio) - 1);
279 call_bio_endio(r1_bio);
285 * Update disk head position estimator based on IRQ completion info.
287 static inline void update_head_pos(int disk, struct r1bio *r1_bio)
289 struct r1conf *conf = r1_bio->mddev->private;
291 conf->mirrors[disk].head_position =
292 r1_bio->sector + (r1_bio->sectors);
296 * Find the disk number which triggered given bio
298 static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
301 struct r1conf *conf = r1_bio->mddev->private;
302 int raid_disks = conf->raid_disks;
304 for (mirror = 0; mirror < raid_disks * 2; mirror++)
305 if (r1_bio->bios[mirror] == bio)
308 BUG_ON(mirror == raid_disks * 2);
309 update_head_pos(mirror, r1_bio);
314 static void raid1_end_read_request(struct bio *bio)
316 int uptodate = !bio->bi_error;
317 struct r1bio *r1_bio = bio->bi_private;
318 struct r1conf *conf = r1_bio->mddev->private;
319 struct md_rdev *rdev = conf->mirrors[r1_bio->read_disk].rdev;
322 * this branch is our 'one mirror IO has finished' event handler:
324 update_head_pos(r1_bio->read_disk, r1_bio);
327 set_bit(R1BIO_Uptodate, &r1_bio->state);
329 /* If all other devices have failed, we want to return
330 * the error upwards rather than fail the last device.
331 * Here we redefine "uptodate" to mean "Don't want to retry"
334 spin_lock_irqsave(&conf->device_lock, flags);
335 if (r1_bio->mddev->degraded == conf->raid_disks ||
336 (r1_bio->mddev->degraded == conf->raid_disks-1 &&
337 test_bit(In_sync, &rdev->flags)))
339 spin_unlock_irqrestore(&conf->device_lock, flags);
343 raid_end_bio_io(r1_bio);
344 rdev_dec_pending(rdev, conf->mddev);
349 char b[BDEVNAME_SIZE];
350 pr_err_ratelimited("md/raid1:%s: %s: rescheduling sector %llu\n",
352 bdevname(rdev->bdev, b),
353 (unsigned long long)r1_bio->sector);
354 set_bit(R1BIO_ReadError, &r1_bio->state);
355 reschedule_retry(r1_bio);
356 /* don't drop the reference on read_disk yet */
360 static void close_write(struct r1bio *r1_bio)
362 /* it really is the end of this request */
363 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
364 /* free extra copy of the data pages */
365 int i = r1_bio->behind_page_count;
367 safe_put_page(r1_bio->behind_bvecs[i].bv_page);
368 kfree(r1_bio->behind_bvecs);
369 r1_bio->behind_bvecs = NULL;
371 /* clear the bitmap if all writes complete successfully */
372 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
374 !test_bit(R1BIO_Degraded, &r1_bio->state),
375 test_bit(R1BIO_BehindIO, &r1_bio->state));
376 md_write_end(r1_bio->mddev);
379 static void r1_bio_write_done(struct r1bio *r1_bio)
381 if (!atomic_dec_and_test(&r1_bio->remaining))
384 if (test_bit(R1BIO_WriteError, &r1_bio->state))
385 reschedule_retry(r1_bio);
388 if (test_bit(R1BIO_MadeGood, &r1_bio->state))
389 reschedule_retry(r1_bio);
391 raid_end_bio_io(r1_bio);
395 static void raid1_end_write_request(struct bio *bio)
397 struct r1bio *r1_bio = bio->bi_private;
398 int behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
399 struct r1conf *conf = r1_bio->mddev->private;
400 struct bio *to_put = NULL;
401 int mirror = find_bio_disk(r1_bio, bio);
402 struct md_rdev *rdev = conf->mirrors[mirror].rdev;
405 discard_error = bio->bi_error && bio_op(bio) == REQ_OP_DISCARD;
408 * 'one mirror IO has finished' event handler:
410 if (bio->bi_error && !discard_error) {
411 set_bit(WriteErrorSeen, &rdev->flags);
412 if (!test_and_set_bit(WantReplacement, &rdev->flags))
413 set_bit(MD_RECOVERY_NEEDED, &
414 conf->mddev->recovery);
416 set_bit(R1BIO_WriteError, &r1_bio->state);
419 * Set R1BIO_Uptodate in our master bio, so that we
420 * will return a good error code for to the higher
421 * levels even if IO on some other mirrored buffer
424 * The 'master' represents the composite IO operation
425 * to user-side. So if something waits for IO, then it
426 * will wait for the 'master' bio.
431 r1_bio->bios[mirror] = NULL;
434 * Do not set R1BIO_Uptodate if the current device is
435 * rebuilding or Faulty. This is because we cannot use
436 * such device for properly reading the data back (we could
437 * potentially use it, if the current write would have felt
438 * before rdev->recovery_offset, but for simplicity we don't
441 if (test_bit(In_sync, &rdev->flags) &&
442 !test_bit(Faulty, &rdev->flags))
443 set_bit(R1BIO_Uptodate, &r1_bio->state);
445 /* Maybe we can clear some bad blocks. */
446 if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
447 &first_bad, &bad_sectors) && !discard_error) {
448 r1_bio->bios[mirror] = IO_MADE_GOOD;
449 set_bit(R1BIO_MadeGood, &r1_bio->state);
454 if (test_bit(WriteMostly, &rdev->flags))
455 atomic_dec(&r1_bio->behind_remaining);
458 * In behind mode, we ACK the master bio once the I/O
459 * has safely reached all non-writemostly
460 * disks. Setting the Returned bit ensures that this
461 * gets done only once -- we don't ever want to return
462 * -EIO here, instead we'll wait
464 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
465 test_bit(R1BIO_Uptodate, &r1_bio->state)) {
466 /* Maybe we can return now */
467 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
468 struct bio *mbio = r1_bio->master_bio;
469 pr_debug("raid1: behind end write sectors"
471 (unsigned long long) mbio->bi_iter.bi_sector,
472 (unsigned long long) bio_end_sector(mbio) - 1);
473 call_bio_endio(r1_bio);
477 if (r1_bio->bios[mirror] == NULL)
478 rdev_dec_pending(rdev, conf->mddev);
481 * Let's see if all mirrored write operations have finished
484 r1_bio_write_done(r1_bio);
491 * This routine returns the disk from which the requested read should
492 * be done. There is a per-array 'next expected sequential IO' sector
493 * number - if this matches on the next IO then we use the last disk.
494 * There is also a per-disk 'last know head position' sector that is
495 * maintained from IRQ contexts, both the normal and the resync IO
496 * completion handlers update this position correctly. If there is no
497 * perfect sequential match then we pick the disk whose head is closest.
499 * If there are 2 mirrors in the same 2 devices, performance degrades
500 * because position is mirror, not device based.
502 * The rdev for the device selected will have nr_pending incremented.
504 static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sectors)
506 const sector_t this_sector = r1_bio->sector;
508 int best_good_sectors;
509 int best_disk, best_dist_disk, best_pending_disk;
513 unsigned int min_pending;
514 struct md_rdev *rdev;
516 int choose_next_idle;
520 * Check if we can balance. We can balance on the whole
521 * device if no resync is going on, or below the resync window.
522 * We take the first readable disk when above the resync window.
525 sectors = r1_bio->sectors;
528 best_dist = MaxSector;
529 best_pending_disk = -1;
530 min_pending = UINT_MAX;
531 best_good_sectors = 0;
533 choose_next_idle = 0;
535 if ((conf->mddev->recovery_cp < this_sector + sectors) ||
536 (mddev_is_clustered(conf->mddev) &&
537 md_cluster_ops->area_resyncing(conf->mddev, READ, this_sector,
538 this_sector + sectors)))
543 for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
547 unsigned int pending;
550 rdev = rcu_dereference(conf->mirrors[disk].rdev);
551 if (r1_bio->bios[disk] == IO_BLOCKED
553 || test_bit(Faulty, &rdev->flags))
555 if (!test_bit(In_sync, &rdev->flags) &&
556 rdev->recovery_offset < this_sector + sectors)
558 if (test_bit(WriteMostly, &rdev->flags)) {
559 /* Don't balance among write-mostly, just
560 * use the first as a last resort */
561 if (best_dist_disk < 0) {
562 if (is_badblock(rdev, this_sector, sectors,
563 &first_bad, &bad_sectors)) {
564 if (first_bad <= this_sector)
565 /* Cannot use this */
567 best_good_sectors = first_bad - this_sector;
569 best_good_sectors = sectors;
570 best_dist_disk = disk;
571 best_pending_disk = disk;
575 /* This is a reasonable device to use. It might
578 if (is_badblock(rdev, this_sector, sectors,
579 &first_bad, &bad_sectors)) {
580 if (best_dist < MaxSector)
581 /* already have a better device */
583 if (first_bad <= this_sector) {
584 /* cannot read here. If this is the 'primary'
585 * device, then we must not read beyond
586 * bad_sectors from another device..
588 bad_sectors -= (this_sector - first_bad);
589 if (choose_first && sectors > bad_sectors)
590 sectors = bad_sectors;
591 if (best_good_sectors > sectors)
592 best_good_sectors = sectors;
595 sector_t good_sectors = first_bad - this_sector;
596 if (good_sectors > best_good_sectors) {
597 best_good_sectors = good_sectors;
605 best_good_sectors = sectors;
607 nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
608 has_nonrot_disk |= nonrot;
609 pending = atomic_read(&rdev->nr_pending);
610 dist = abs(this_sector - conf->mirrors[disk].head_position);
615 /* Don't change to another disk for sequential reads */
616 if (conf->mirrors[disk].next_seq_sect == this_sector
618 int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
619 struct raid1_info *mirror = &conf->mirrors[disk];
623 * If buffered sequential IO size exceeds optimal
624 * iosize, check if there is idle disk. If yes, choose
625 * the idle disk. read_balance could already choose an
626 * idle disk before noticing it's a sequential IO in
627 * this disk. This doesn't matter because this disk
628 * will idle, next time it will be utilized after the
629 * first disk has IO size exceeds optimal iosize. In
630 * this way, iosize of the first disk will be optimal
631 * iosize at least. iosize of the second disk might be
632 * small, but not a big deal since when the second disk
633 * starts IO, the first disk is likely still busy.
635 if (nonrot && opt_iosize > 0 &&
636 mirror->seq_start != MaxSector &&
637 mirror->next_seq_sect > opt_iosize &&
638 mirror->next_seq_sect - opt_iosize >=
640 choose_next_idle = 1;
645 /* If device is idle, use it */
651 if (choose_next_idle)
654 if (min_pending > pending) {
655 min_pending = pending;
656 best_pending_disk = disk;
659 if (dist < best_dist) {
661 best_dist_disk = disk;
666 * If all disks are rotational, choose the closest disk. If any disk is
667 * non-rotational, choose the disk with less pending request even the
668 * disk is rotational, which might/might not be optimal for raids with
669 * mixed ratation/non-rotational disks depending on workload.
671 if (best_disk == -1) {
673 best_disk = best_pending_disk;
675 best_disk = best_dist_disk;
678 if (best_disk >= 0) {
679 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
682 atomic_inc(&rdev->nr_pending);
683 sectors = best_good_sectors;
685 if (conf->mirrors[best_disk].next_seq_sect != this_sector)
686 conf->mirrors[best_disk].seq_start = this_sector;
688 conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
691 *max_sectors = sectors;
696 static int raid1_congested(struct mddev *mddev, int bits)
698 struct r1conf *conf = mddev->private;
701 if ((bits & (1 << WB_async_congested)) &&
702 conf->pending_count >= max_queued_requests)
706 for (i = 0; i < conf->raid_disks * 2; i++) {
707 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
708 if (rdev && !test_bit(Faulty, &rdev->flags)) {
709 struct request_queue *q = bdev_get_queue(rdev->bdev);
713 /* Note the '|| 1' - when read_balance prefers
714 * non-congested targets, it can be removed
716 if ((bits & (1 << WB_async_congested)) || 1)
717 ret |= bdi_congested(&q->backing_dev_info, bits);
719 ret &= bdi_congested(&q->backing_dev_info, bits);
726 static void flush_pending_writes(struct r1conf *conf)
728 /* Any writes that have been queued but are awaiting
729 * bitmap updates get flushed here.
731 spin_lock_irq(&conf->device_lock);
733 if (conf->pending_bio_list.head) {
735 bio = bio_list_get(&conf->pending_bio_list);
736 conf->pending_count = 0;
737 spin_unlock_irq(&conf->device_lock);
738 /* flush any pending bitmap writes to
739 * disk before proceeding w/ I/O */
740 bitmap_unplug(conf->mddev->bitmap);
741 wake_up(&conf->wait_barrier);
743 while (bio) { /* submit pending writes */
744 struct bio *next = bio->bi_next;
745 struct md_rdev *rdev = (void*)bio->bi_bdev;
747 bio->bi_bdev = rdev->bdev;
748 if (test_bit(Faulty, &rdev->flags)) {
749 bio->bi_error = -EIO;
751 } else if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
752 !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
756 generic_make_request(bio);
760 spin_unlock_irq(&conf->device_lock);
764 * Sometimes we need to suspend IO while we do something else,
765 * either some resync/recovery, or reconfigure the array.
766 * To do this we raise a 'barrier'.
767 * The 'barrier' is a counter that can be raised multiple times
768 * to count how many activities are happening which preclude
770 * We can only raise the barrier if there is no pending IO.
771 * i.e. if nr_pending == 0.
772 * We choose only to raise the barrier if no-one is waiting for the
773 * barrier to go down. This means that as soon as an IO request
774 * is ready, no other operations which require a barrier will start
775 * until the IO request has had a chance.
777 * So: regular IO calls 'wait_barrier'. When that returns there
778 * is no backgroup IO happening, It must arrange to call
779 * allow_barrier when it has finished its IO.
780 * backgroup IO calls must call raise_barrier. Once that returns
781 * there is no normal IO happeing. It must arrange to call
782 * lower_barrier when the particular background IO completes.
784 static void raise_barrier(struct r1conf *conf, sector_t sector_nr)
786 spin_lock_irq(&conf->resync_lock);
788 /* Wait until no block IO is waiting */
789 wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
792 /* block any new IO from starting */
794 conf->next_resync = sector_nr;
796 /* For these conditions we must wait:
797 * A: while the array is in frozen state
798 * B: while barrier >= RESYNC_DEPTH, meaning resync reach
799 * the max count which allowed.
800 * C: next_resync + RESYNC_SECTORS > start_next_window, meaning
801 * next resync will reach to the window which normal bios are
803 * D: while there are any active requests in the current window.
805 wait_event_lock_irq(conf->wait_barrier,
806 !conf->array_frozen &&
807 conf->barrier < RESYNC_DEPTH &&
808 conf->current_window_requests == 0 &&
809 (conf->start_next_window >=
810 conf->next_resync + RESYNC_SECTORS),
814 spin_unlock_irq(&conf->resync_lock);
817 static void lower_barrier(struct r1conf *conf)
820 BUG_ON(conf->barrier <= 0);
821 spin_lock_irqsave(&conf->resync_lock, flags);
824 spin_unlock_irqrestore(&conf->resync_lock, flags);
825 wake_up(&conf->wait_barrier);
828 static bool need_to_wait_for_sync(struct r1conf *conf, struct bio *bio)
832 if (conf->array_frozen || !bio)
834 else if (conf->barrier && bio_data_dir(bio) == WRITE) {
835 if ((conf->mddev->curr_resync_completed
836 >= bio_end_sector(bio)) ||
837 (conf->next_resync + NEXT_NORMALIO_DISTANCE
838 <= bio->bi_iter.bi_sector))
847 static sector_t wait_barrier(struct r1conf *conf, struct bio *bio)
851 spin_lock_irq(&conf->resync_lock);
852 if (need_to_wait_for_sync(conf, bio)) {
854 /* Wait for the barrier to drop.
855 * However if there are already pending
856 * requests (preventing the barrier from
857 * rising completely), and the
858 * per-process bio queue isn't empty,
859 * then don't wait, as we need to empty
860 * that queue to allow conf->start_next_window
863 wait_event_lock_irq(conf->wait_barrier,
864 !conf->array_frozen &&
866 ((conf->start_next_window <
867 conf->next_resync + RESYNC_SECTORS) &&
869 !bio_list_empty(current->bio_list))),
874 if (bio && bio_data_dir(bio) == WRITE) {
875 if (bio->bi_iter.bi_sector >= conf->next_resync) {
876 if (conf->start_next_window == MaxSector)
877 conf->start_next_window =
879 NEXT_NORMALIO_DISTANCE;
881 if ((conf->start_next_window + NEXT_NORMALIO_DISTANCE)
882 <= bio->bi_iter.bi_sector)
883 conf->next_window_requests++;
885 conf->current_window_requests++;
886 sector = conf->start_next_window;
891 spin_unlock_irq(&conf->resync_lock);
895 static void allow_barrier(struct r1conf *conf, sector_t start_next_window,
900 spin_lock_irqsave(&conf->resync_lock, flags);
902 if (start_next_window) {
903 if (start_next_window == conf->start_next_window) {
904 if (conf->start_next_window + NEXT_NORMALIO_DISTANCE
906 conf->next_window_requests--;
908 conf->current_window_requests--;
910 conf->current_window_requests--;
912 if (!conf->current_window_requests) {
913 if (conf->next_window_requests) {
914 conf->current_window_requests =
915 conf->next_window_requests;
916 conf->next_window_requests = 0;
917 conf->start_next_window +=
918 NEXT_NORMALIO_DISTANCE;
920 conf->start_next_window = MaxSector;
923 spin_unlock_irqrestore(&conf->resync_lock, flags);
924 wake_up(&conf->wait_barrier);
927 static void freeze_array(struct r1conf *conf, int extra)
929 /* stop syncio and normal IO and wait for everything to
931 * We wait until nr_pending match nr_queued+extra
932 * This is called in the context of one normal IO request
933 * that has failed. Thus any sync request that might be pending
934 * will be blocked by nr_pending, and we need to wait for
935 * pending IO requests to complete or be queued for re-try.
936 * Thus the number queued (nr_queued) plus this request (extra)
937 * must match the number of pending IOs (nr_pending) before
940 spin_lock_irq(&conf->resync_lock);
941 conf->array_frozen = 1;
942 wait_event_lock_irq_cmd(conf->wait_barrier,
943 conf->nr_pending == conf->nr_queued+extra,
945 flush_pending_writes(conf));
946 spin_unlock_irq(&conf->resync_lock);
948 static void unfreeze_array(struct r1conf *conf)
950 /* reverse the effect of the freeze */
951 spin_lock_irq(&conf->resync_lock);
952 conf->array_frozen = 0;
953 wake_up(&conf->wait_barrier);
954 spin_unlock_irq(&conf->resync_lock);
957 /* duplicate the data pages for behind I/O
959 static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio)
962 struct bio_vec *bvec;
963 struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
965 if (unlikely(!bvecs))
968 bio_for_each_segment_all(bvec, bio, i) {
970 bvecs[i].bv_page = alloc_page(GFP_NOIO);
971 if (unlikely(!bvecs[i].bv_page))
973 memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
974 kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
975 kunmap(bvecs[i].bv_page);
976 kunmap(bvec->bv_page);
978 r1_bio->behind_bvecs = bvecs;
979 r1_bio->behind_page_count = bio->bi_vcnt;
980 set_bit(R1BIO_BehindIO, &r1_bio->state);
984 for (i = 0; i < bio->bi_vcnt; i++)
985 if (bvecs[i].bv_page)
986 put_page(bvecs[i].bv_page);
988 pr_debug("%dB behind alloc failed, doing sync I/O\n",
989 bio->bi_iter.bi_size);
992 struct raid1_plug_cb {
993 struct blk_plug_cb cb;
994 struct bio_list pending;
998 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
1000 struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
1002 struct mddev *mddev = plug->cb.data;
1003 struct r1conf *conf = mddev->private;
1006 if (from_schedule || current->bio_list) {
1007 spin_lock_irq(&conf->device_lock);
1008 bio_list_merge(&conf->pending_bio_list, &plug->pending);
1009 conf->pending_count += plug->pending_cnt;
1010 spin_unlock_irq(&conf->device_lock);
1011 wake_up(&conf->wait_barrier);
1012 md_wakeup_thread(mddev->thread);
1017 /* we aren't scheduling, so we can do the write-out directly. */
1018 bio = bio_list_get(&plug->pending);
1019 bitmap_unplug(mddev->bitmap);
1020 wake_up(&conf->wait_barrier);
1022 while (bio) { /* submit pending writes */
1023 struct bio *next = bio->bi_next;
1024 struct md_rdev *rdev = (void*)bio->bi_bdev;
1025 bio->bi_next = NULL;
1026 bio->bi_bdev = rdev->bdev;
1027 if (test_bit(Faulty, &rdev->flags)) {
1028 bio->bi_error = -EIO;
1030 } else if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
1031 !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
1032 /* Just ignore it */
1035 generic_make_request(bio);
1041 static void raid1_make_request(struct mddev *mddev, struct bio * bio)
1043 struct r1conf *conf = mddev->private;
1044 struct raid1_info *mirror;
1045 struct r1bio *r1_bio;
1046 struct bio *read_bio;
1048 struct bitmap *bitmap;
1049 unsigned long flags;
1050 const int op = bio_op(bio);
1051 const int rw = bio_data_dir(bio);
1052 const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1053 const unsigned long do_flush_fua = (bio->bi_opf &
1054 (REQ_PREFLUSH | REQ_FUA));
1055 struct md_rdev *blocked_rdev;
1056 struct blk_plug_cb *cb;
1057 struct raid1_plug_cb *plug = NULL;
1059 int sectors_handled;
1061 sector_t start_next_window;
1064 * Register the new request and wait if the reconstruction
1065 * thread has put up a bar for new requests.
1066 * Continue immediately if no resync is active currently.
1069 md_write_start(mddev, bio); /* wait on superblock update early */
1071 if (bio_data_dir(bio) == WRITE &&
1072 ((bio_end_sector(bio) > mddev->suspend_lo &&
1073 bio->bi_iter.bi_sector < mddev->suspend_hi) ||
1074 (mddev_is_clustered(mddev) &&
1075 md_cluster_ops->area_resyncing(mddev, WRITE,
1076 bio->bi_iter.bi_sector, bio_end_sector(bio))))) {
1077 /* As the suspend_* range is controlled by
1078 * userspace, we want an interruptible
1083 flush_signals(current);
1084 prepare_to_wait(&conf->wait_barrier,
1085 &w, TASK_INTERRUPTIBLE);
1086 if (bio_end_sector(bio) <= mddev->suspend_lo ||
1087 bio->bi_iter.bi_sector >= mddev->suspend_hi ||
1088 (mddev_is_clustered(mddev) &&
1089 !md_cluster_ops->area_resyncing(mddev, WRITE,
1090 bio->bi_iter.bi_sector, bio_end_sector(bio))))
1094 finish_wait(&conf->wait_barrier, &w);
1097 start_next_window = wait_barrier(conf, bio);
1099 bitmap = mddev->bitmap;
1102 * make_request() can abort the operation when read-ahead is being
1103 * used and no empty request is available.
1106 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1108 r1_bio->master_bio = bio;
1109 r1_bio->sectors = bio_sectors(bio);
1111 r1_bio->mddev = mddev;
1112 r1_bio->sector = bio->bi_iter.bi_sector;
1114 /* We might need to issue multiple reads to different
1115 * devices if there are bad blocks around, so we keep
1116 * track of the number of reads in bio->bi_phys_segments.
1117 * If this is 0, there is only one r1_bio and no locking
1118 * will be needed when requests complete. If it is
1119 * non-zero, then it is the number of not-completed requests.
1121 bio->bi_phys_segments = 0;
1122 bio_clear_flag(bio, BIO_SEG_VALID);
1126 * read balancing logic:
1131 rdisk = read_balance(conf, r1_bio, &max_sectors);
1134 /* couldn't find anywhere to read from */
1135 raid_end_bio_io(r1_bio);
1138 mirror = conf->mirrors + rdisk;
1140 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1142 /* Reading from a write-mostly device must
1143 * take care not to over-take any writes
1146 wait_event(bitmap->behind_wait,
1147 atomic_read(&bitmap->behind_writes) == 0);
1149 r1_bio->read_disk = rdisk;
1150 r1_bio->start_next_window = 0;
1152 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1153 bio_trim(read_bio, r1_bio->sector - bio->bi_iter.bi_sector,
1156 r1_bio->bios[rdisk] = read_bio;
1158 read_bio->bi_iter.bi_sector = r1_bio->sector +
1159 mirror->rdev->data_offset;
1160 read_bio->bi_bdev = mirror->rdev->bdev;
1161 read_bio->bi_end_io = raid1_end_read_request;
1162 bio_set_op_attrs(read_bio, op, do_sync);
1163 read_bio->bi_private = r1_bio;
1165 if (max_sectors < r1_bio->sectors) {
1166 /* could not read all from this device, so we will
1167 * need another r1_bio.
1170 sectors_handled = (r1_bio->sector + max_sectors
1171 - bio->bi_iter.bi_sector);
1172 r1_bio->sectors = max_sectors;
1173 spin_lock_irq(&conf->device_lock);
1174 if (bio->bi_phys_segments == 0)
1175 bio->bi_phys_segments = 2;
1177 bio->bi_phys_segments++;
1178 spin_unlock_irq(&conf->device_lock);
1179 /* Cannot call generic_make_request directly
1180 * as that will be queued in __make_request
1181 * and subsequent mempool_alloc might block waiting
1182 * for it. So hand bio over to raid1d.
1184 reschedule_retry(r1_bio);
1186 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1188 r1_bio->master_bio = bio;
1189 r1_bio->sectors = bio_sectors(bio) - sectors_handled;
1191 r1_bio->mddev = mddev;
1192 r1_bio->sector = bio->bi_iter.bi_sector +
1196 generic_make_request(read_bio);
1203 if (conf->pending_count >= max_queued_requests) {
1204 md_wakeup_thread(mddev->thread);
1205 wait_event(conf->wait_barrier,
1206 conf->pending_count < max_queued_requests);
1208 /* first select target devices under rcu_lock and
1209 * inc refcount on their rdev. Record them by setting
1211 * If there are known/acknowledged bad blocks on any device on
1212 * which we have seen a write error, we want to avoid writing those
1214 * This potentially requires several writes to write around
1215 * the bad blocks. Each set of writes gets it's own r1bio
1216 * with a set of bios attached.
1219 disks = conf->raid_disks * 2;
1221 r1_bio->start_next_window = start_next_window;
1222 blocked_rdev = NULL;
1224 max_sectors = r1_bio->sectors;
1225 for (i = 0; i < disks; i++) {
1226 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1227 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1228 atomic_inc(&rdev->nr_pending);
1229 blocked_rdev = rdev;
1232 r1_bio->bios[i] = NULL;
1233 if (!rdev || test_bit(Faulty, &rdev->flags)) {
1234 if (i < conf->raid_disks)
1235 set_bit(R1BIO_Degraded, &r1_bio->state);
1239 atomic_inc(&rdev->nr_pending);
1240 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1245 is_bad = is_badblock(rdev, r1_bio->sector,
1247 &first_bad, &bad_sectors);
1249 /* mustn't write here until the bad block is
1251 set_bit(BlockedBadBlocks, &rdev->flags);
1252 blocked_rdev = rdev;
1255 if (is_bad && first_bad <= r1_bio->sector) {
1256 /* Cannot write here at all */
1257 bad_sectors -= (r1_bio->sector - first_bad);
1258 if (bad_sectors < max_sectors)
1259 /* mustn't write more than bad_sectors
1260 * to other devices yet
1262 max_sectors = bad_sectors;
1263 rdev_dec_pending(rdev, mddev);
1264 /* We don't set R1BIO_Degraded as that
1265 * only applies if the disk is
1266 * missing, so it might be re-added,
1267 * and we want to know to recover this
1269 * In this case the device is here,
1270 * and the fact that this chunk is not
1271 * in-sync is recorded in the bad
1277 int good_sectors = first_bad - r1_bio->sector;
1278 if (good_sectors < max_sectors)
1279 max_sectors = good_sectors;
1282 r1_bio->bios[i] = bio;
1286 if (unlikely(blocked_rdev)) {
1287 /* Wait for this device to become unblocked */
1289 sector_t old = start_next_window;
1291 for (j = 0; j < i; j++)
1292 if (r1_bio->bios[j])
1293 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1295 allow_barrier(conf, start_next_window, bio->bi_iter.bi_sector);
1296 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1297 start_next_window = wait_barrier(conf, bio);
1299 * We must make sure the multi r1bios of bio have
1300 * the same value of bi_phys_segments
1302 if (bio->bi_phys_segments && old &&
1303 old != start_next_window)
1304 /* Wait for the former r1bio(s) to complete */
1305 wait_event(conf->wait_barrier,
1306 bio->bi_phys_segments == 1);
1310 if (max_sectors < r1_bio->sectors) {
1311 /* We are splitting this write into multiple parts, so
1312 * we need to prepare for allocating another r1_bio.
1314 r1_bio->sectors = max_sectors;
1315 spin_lock_irq(&conf->device_lock);
1316 if (bio->bi_phys_segments == 0)
1317 bio->bi_phys_segments = 2;
1319 bio->bi_phys_segments++;
1320 spin_unlock_irq(&conf->device_lock);
1322 sectors_handled = r1_bio->sector + max_sectors - bio->bi_iter.bi_sector;
1324 atomic_set(&r1_bio->remaining, 1);
1325 atomic_set(&r1_bio->behind_remaining, 0);
1328 for (i = 0; i < disks; i++) {
1330 if (!r1_bio->bios[i])
1333 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1334 bio_trim(mbio, r1_bio->sector - bio->bi_iter.bi_sector, max_sectors);
1338 * Not if there are too many, or cannot
1339 * allocate memory, or a reader on WriteMostly
1340 * is waiting for behind writes to flush */
1342 (atomic_read(&bitmap->behind_writes)
1343 < mddev->bitmap_info.max_write_behind) &&
1344 !waitqueue_active(&bitmap->behind_wait))
1345 alloc_behind_pages(mbio, r1_bio);
1347 bitmap_startwrite(bitmap, r1_bio->sector,
1349 test_bit(R1BIO_BehindIO,
1353 if (r1_bio->behind_bvecs) {
1354 struct bio_vec *bvec;
1358 * We trimmed the bio, so _all is legit
1360 bio_for_each_segment_all(bvec, mbio, j)
1361 bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
1362 if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1363 atomic_inc(&r1_bio->behind_remaining);
1366 r1_bio->bios[i] = mbio;
1368 mbio->bi_iter.bi_sector = (r1_bio->sector +
1369 conf->mirrors[i].rdev->data_offset);
1370 mbio->bi_bdev = (void*)conf->mirrors[i].rdev;
1371 mbio->bi_end_io = raid1_end_write_request;
1372 bio_set_op_attrs(mbio, op, do_flush_fua | do_sync);
1373 mbio->bi_private = r1_bio;
1375 atomic_inc(&r1_bio->remaining);
1377 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1379 plug = container_of(cb, struct raid1_plug_cb, cb);
1382 spin_lock_irqsave(&conf->device_lock, flags);
1384 bio_list_add(&plug->pending, mbio);
1385 plug->pending_cnt++;
1387 bio_list_add(&conf->pending_bio_list, mbio);
1388 conf->pending_count++;
1390 spin_unlock_irqrestore(&conf->device_lock, flags);
1392 md_wakeup_thread(mddev->thread);
1394 /* Mustn't call r1_bio_write_done before this next test,
1395 * as it could result in the bio being freed.
1397 if (sectors_handled < bio_sectors(bio)) {
1398 r1_bio_write_done(r1_bio);
1399 /* We need another r1_bio. It has already been counted
1400 * in bio->bi_phys_segments
1402 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1403 r1_bio->master_bio = bio;
1404 r1_bio->sectors = bio_sectors(bio) - sectors_handled;
1406 r1_bio->mddev = mddev;
1407 r1_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
1411 r1_bio_write_done(r1_bio);
1413 /* In case raid1d snuck in to freeze_array */
1414 wake_up(&conf->wait_barrier);
1417 static void raid1_status(struct seq_file *seq, struct mddev *mddev)
1419 struct r1conf *conf = mddev->private;
1422 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1423 conf->raid_disks - mddev->degraded);
1425 for (i = 0; i < conf->raid_disks; i++) {
1426 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1427 seq_printf(seq, "%s",
1428 rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1431 seq_printf(seq, "]");
1434 static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
1436 char b[BDEVNAME_SIZE];
1437 struct r1conf *conf = mddev->private;
1438 unsigned long flags;
1441 * If it is not operational, then we have already marked it as dead
1442 * else if it is the last working disks, ignore the error, let the
1443 * next level up know.
1444 * else mark the drive as failed
1446 if (test_bit(In_sync, &rdev->flags)
1447 && (conf->raid_disks - mddev->degraded) == 1) {
1449 * Don't fail the drive, act as though we were just a
1450 * normal single drive.
1451 * However don't try a recovery from this drive as
1452 * it is very likely to fail.
1454 conf->recovery_disabled = mddev->recovery_disabled;
1457 set_bit(Blocked, &rdev->flags);
1458 spin_lock_irqsave(&conf->device_lock, flags);
1459 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1461 set_bit(Faulty, &rdev->flags);
1463 set_bit(Faulty, &rdev->flags);
1464 spin_unlock_irqrestore(&conf->device_lock, flags);
1466 * if recovery is running, make sure it aborts.
1468 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1469 set_mask_bits(&mddev->flags, 0,
1470 BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));
1471 pr_crit("md/raid1:%s: Disk failure on %s, disabling device.\n"
1472 "md/raid1:%s: Operation continuing on %d devices.\n",
1473 mdname(mddev), bdevname(rdev->bdev, b),
1474 mdname(mddev), conf->raid_disks - mddev->degraded);
1477 static void print_conf(struct r1conf *conf)
1481 pr_debug("RAID1 conf printout:\n");
1483 pr_debug("(!conf)\n");
1486 pr_debug(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1490 for (i = 0; i < conf->raid_disks; i++) {
1491 char b[BDEVNAME_SIZE];
1492 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1494 pr_debug(" disk %d, wo:%d, o:%d, dev:%s\n",
1495 i, !test_bit(In_sync, &rdev->flags),
1496 !test_bit(Faulty, &rdev->flags),
1497 bdevname(rdev->bdev,b));
1502 static void close_sync(struct r1conf *conf)
1504 wait_barrier(conf, NULL);
1505 allow_barrier(conf, 0, 0);
1507 mempool_destroy(conf->r1buf_pool);
1508 conf->r1buf_pool = NULL;
1510 spin_lock_irq(&conf->resync_lock);
1511 conf->next_resync = MaxSector - 2 * NEXT_NORMALIO_DISTANCE;
1512 conf->start_next_window = MaxSector;
1513 conf->current_window_requests +=
1514 conf->next_window_requests;
1515 conf->next_window_requests = 0;
1516 spin_unlock_irq(&conf->resync_lock);
1519 static int raid1_spare_active(struct mddev *mddev)
1522 struct r1conf *conf = mddev->private;
1524 unsigned long flags;
1527 * Find all failed disks within the RAID1 configuration
1528 * and mark them readable.
1529 * Called under mddev lock, so rcu protection not needed.
1530 * device_lock used to avoid races with raid1_end_read_request
1531 * which expects 'In_sync' flags and ->degraded to be consistent.
1533 spin_lock_irqsave(&conf->device_lock, flags);
1534 for (i = 0; i < conf->raid_disks; i++) {
1535 struct md_rdev *rdev = conf->mirrors[i].rdev;
1536 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1538 && !test_bit(Candidate, &repl->flags)
1539 && repl->recovery_offset == MaxSector
1540 && !test_bit(Faulty, &repl->flags)
1541 && !test_and_set_bit(In_sync, &repl->flags)) {
1542 /* replacement has just become active */
1544 !test_and_clear_bit(In_sync, &rdev->flags))
1547 /* Replaced device not technically
1548 * faulty, but we need to be sure
1549 * it gets removed and never re-added
1551 set_bit(Faulty, &rdev->flags);
1552 sysfs_notify_dirent_safe(
1557 && rdev->recovery_offset == MaxSector
1558 && !test_bit(Faulty, &rdev->flags)
1559 && !test_and_set_bit(In_sync, &rdev->flags)) {
1561 sysfs_notify_dirent_safe(rdev->sysfs_state);
1564 mddev->degraded -= count;
1565 spin_unlock_irqrestore(&conf->device_lock, flags);
1571 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1573 struct r1conf *conf = mddev->private;
1576 struct raid1_info *p;
1578 int last = conf->raid_disks - 1;
1580 if (mddev->recovery_disabled == conf->recovery_disabled)
1583 if (md_integrity_add_rdev(rdev, mddev))
1586 if (rdev->raid_disk >= 0)
1587 first = last = rdev->raid_disk;
1590 * find the disk ... but prefer rdev->saved_raid_disk
1593 if (rdev->saved_raid_disk >= 0 &&
1594 rdev->saved_raid_disk >= first &&
1595 conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1596 first = last = rdev->saved_raid_disk;
1598 for (mirror = first; mirror <= last; mirror++) {
1599 p = conf->mirrors+mirror;
1603 disk_stack_limits(mddev->gendisk, rdev->bdev,
1604 rdev->data_offset << 9);
1606 p->head_position = 0;
1607 rdev->raid_disk = mirror;
1609 /* As all devices are equivalent, we don't need a full recovery
1610 * if this was recently any drive of the array
1612 if (rdev->saved_raid_disk < 0)
1614 rcu_assign_pointer(p->rdev, rdev);
1617 if (test_bit(WantReplacement, &p->rdev->flags) &&
1618 p[conf->raid_disks].rdev == NULL) {
1619 /* Add this device as a replacement */
1620 clear_bit(In_sync, &rdev->flags);
1621 set_bit(Replacement, &rdev->flags);
1622 rdev->raid_disk = mirror;
1625 rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1629 if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
1630 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1635 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1637 struct r1conf *conf = mddev->private;
1639 int number = rdev->raid_disk;
1640 struct raid1_info *p = conf->mirrors + number;
1642 if (rdev != p->rdev)
1643 p = conf->mirrors + conf->raid_disks + number;
1646 if (rdev == p->rdev) {
1647 if (test_bit(In_sync, &rdev->flags) ||
1648 atomic_read(&rdev->nr_pending)) {
1652 /* Only remove non-faulty devices if recovery
1655 if (!test_bit(Faulty, &rdev->flags) &&
1656 mddev->recovery_disabled != conf->recovery_disabled &&
1657 mddev->degraded < conf->raid_disks) {
1662 if (!test_bit(RemoveSynchronized, &rdev->flags)) {
1664 if (atomic_read(&rdev->nr_pending)) {
1665 /* lost the race, try later */
1671 if (conf->mirrors[conf->raid_disks + number].rdev) {
1672 /* We just removed a device that is being replaced.
1673 * Move down the replacement. We drain all IO before
1674 * doing this to avoid confusion.
1676 struct md_rdev *repl =
1677 conf->mirrors[conf->raid_disks + number].rdev;
1678 freeze_array(conf, 0);
1679 clear_bit(Replacement, &repl->flags);
1681 conf->mirrors[conf->raid_disks + number].rdev = NULL;
1682 unfreeze_array(conf);
1683 clear_bit(WantReplacement, &rdev->flags);
1685 clear_bit(WantReplacement, &rdev->flags);
1686 err = md_integrity_register(mddev);
1694 static void end_sync_read(struct bio *bio)
1696 struct r1bio *r1_bio = bio->bi_private;
1698 update_head_pos(r1_bio->read_disk, r1_bio);
1701 * we have read a block, now it needs to be re-written,
1702 * or re-read if the read failed.
1703 * We don't do much here, just schedule handling by raid1d
1706 set_bit(R1BIO_Uptodate, &r1_bio->state);
1708 if (atomic_dec_and_test(&r1_bio->remaining))
1709 reschedule_retry(r1_bio);
1712 static void end_sync_write(struct bio *bio)
1714 int uptodate = !bio->bi_error;
1715 struct r1bio *r1_bio = bio->bi_private;
1716 struct mddev *mddev = r1_bio->mddev;
1717 struct r1conf *conf = mddev->private;
1720 struct md_rdev *rdev = conf->mirrors[find_bio_disk(r1_bio, bio)].rdev;
1723 sector_t sync_blocks = 0;
1724 sector_t s = r1_bio->sector;
1725 long sectors_to_go = r1_bio->sectors;
1726 /* make sure these bits doesn't get cleared. */
1728 bitmap_end_sync(mddev->bitmap, s,
1731 sectors_to_go -= sync_blocks;
1732 } while (sectors_to_go > 0);
1733 set_bit(WriteErrorSeen, &rdev->flags);
1734 if (!test_and_set_bit(WantReplacement, &rdev->flags))
1735 set_bit(MD_RECOVERY_NEEDED, &
1737 set_bit(R1BIO_WriteError, &r1_bio->state);
1738 } else if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
1739 &first_bad, &bad_sectors) &&
1740 !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1743 &first_bad, &bad_sectors)
1745 set_bit(R1BIO_MadeGood, &r1_bio->state);
1747 if (atomic_dec_and_test(&r1_bio->remaining)) {
1748 int s = r1_bio->sectors;
1749 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1750 test_bit(R1BIO_WriteError, &r1_bio->state))
1751 reschedule_retry(r1_bio);
1754 md_done_sync(mddev, s, uptodate);
1759 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1760 int sectors, struct page *page, int rw)
1762 if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
1766 set_bit(WriteErrorSeen, &rdev->flags);
1767 if (!test_and_set_bit(WantReplacement,
1769 set_bit(MD_RECOVERY_NEEDED, &
1770 rdev->mddev->recovery);
1772 /* need to record an error - either for the block or the device */
1773 if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1774 md_error(rdev->mddev, rdev);
1778 static int fix_sync_read_error(struct r1bio *r1_bio)
1780 /* Try some synchronous reads of other devices to get
1781 * good data, much like with normal read errors. Only
1782 * read into the pages we already have so we don't
1783 * need to re-issue the read request.
1784 * We don't need to freeze the array, because being in an
1785 * active sync request, there is no normal IO, and
1786 * no overlapping syncs.
1787 * We don't need to check is_badblock() again as we
1788 * made sure that anything with a bad block in range
1789 * will have bi_end_io clear.
1791 struct mddev *mddev = r1_bio->mddev;
1792 struct r1conf *conf = mddev->private;
1793 struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1794 sector_t sect = r1_bio->sector;
1795 int sectors = r1_bio->sectors;
1800 int d = r1_bio->read_disk;
1802 struct md_rdev *rdev;
1805 if (s > (PAGE_SIZE>>9))
1808 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1809 /* No rcu protection needed here devices
1810 * can only be removed when no resync is
1811 * active, and resync is currently active
1813 rdev = conf->mirrors[d].rdev;
1814 if (sync_page_io(rdev, sect, s<<9,
1815 bio->bi_io_vec[idx].bv_page,
1816 REQ_OP_READ, 0, false)) {
1822 if (d == conf->raid_disks * 2)
1824 } while (!success && d != r1_bio->read_disk);
1827 char b[BDEVNAME_SIZE];
1829 /* Cannot read from anywhere, this block is lost.
1830 * Record a bad block on each device. If that doesn't
1831 * work just disable and interrupt the recovery.
1832 * Don't fail devices as that won't really help.
1834 pr_crit_ratelimited("md/raid1:%s: %s: unrecoverable I/O read error for block %llu\n",
1836 bdevname(bio->bi_bdev, b),
1837 (unsigned long long)r1_bio->sector);
1838 for (d = 0; d < conf->raid_disks * 2; d++) {
1839 rdev = conf->mirrors[d].rdev;
1840 if (!rdev || test_bit(Faulty, &rdev->flags))
1842 if (!rdev_set_badblocks(rdev, sect, s, 0))
1846 conf->recovery_disabled =
1847 mddev->recovery_disabled;
1848 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1849 md_done_sync(mddev, r1_bio->sectors, 0);
1861 /* write it back and re-read */
1862 while (d != r1_bio->read_disk) {
1864 d = conf->raid_disks * 2;
1866 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1868 rdev = conf->mirrors[d].rdev;
1869 if (r1_sync_page_io(rdev, sect, s,
1870 bio->bi_io_vec[idx].bv_page,
1872 r1_bio->bios[d]->bi_end_io = NULL;
1873 rdev_dec_pending(rdev, mddev);
1877 while (d != r1_bio->read_disk) {
1879 d = conf->raid_disks * 2;
1881 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1883 rdev = conf->mirrors[d].rdev;
1884 if (r1_sync_page_io(rdev, sect, s,
1885 bio->bi_io_vec[idx].bv_page,
1887 atomic_add(s, &rdev->corrected_errors);
1893 set_bit(R1BIO_Uptodate, &r1_bio->state);
1898 static void process_checks(struct r1bio *r1_bio)
1900 /* We have read all readable devices. If we haven't
1901 * got the block, then there is no hope left.
1902 * If we have, then we want to do a comparison
1903 * and skip the write if everything is the same.
1904 * If any blocks failed to read, then we need to
1905 * attempt an over-write
1907 struct mddev *mddev = r1_bio->mddev;
1908 struct r1conf *conf = mddev->private;
1913 /* Fix variable parts of all bios */
1914 vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
1915 for (i = 0; i < conf->raid_disks * 2; i++) {
1919 struct bio *b = r1_bio->bios[i];
1920 if (b->bi_end_io != end_sync_read)
1922 /* fixup the bio for reuse, but preserve errno */
1923 error = b->bi_error;
1925 b->bi_error = error;
1927 b->bi_iter.bi_size = r1_bio->sectors << 9;
1928 b->bi_iter.bi_sector = r1_bio->sector +
1929 conf->mirrors[i].rdev->data_offset;
1930 b->bi_bdev = conf->mirrors[i].rdev->bdev;
1931 b->bi_end_io = end_sync_read;
1932 b->bi_private = r1_bio;
1934 size = b->bi_iter.bi_size;
1935 for (j = 0; j < vcnt ; j++) {
1937 bi = &b->bi_io_vec[j];
1939 if (size > PAGE_SIZE)
1940 bi->bv_len = PAGE_SIZE;
1946 for (primary = 0; primary < conf->raid_disks * 2; primary++)
1947 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1948 !r1_bio->bios[primary]->bi_error) {
1949 r1_bio->bios[primary]->bi_end_io = NULL;
1950 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1953 r1_bio->read_disk = primary;
1954 for (i = 0; i < conf->raid_disks * 2; i++) {
1956 struct bio *pbio = r1_bio->bios[primary];
1957 struct bio *sbio = r1_bio->bios[i];
1958 int error = sbio->bi_error;
1960 if (sbio->bi_end_io != end_sync_read)
1962 /* Now we can 'fixup' the error value */
1966 for (j = vcnt; j-- ; ) {
1968 p = pbio->bi_io_vec[j].bv_page;
1969 s = sbio->bi_io_vec[j].bv_page;
1970 if (memcmp(page_address(p),
1972 sbio->bi_io_vec[j].bv_len))
1978 atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
1979 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1981 /* No need to write to this device. */
1982 sbio->bi_end_io = NULL;
1983 rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1987 bio_copy_data(sbio, pbio);
1991 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
1993 struct r1conf *conf = mddev->private;
1995 int disks = conf->raid_disks * 2;
1996 struct bio *bio, *wbio;
1998 bio = r1_bio->bios[r1_bio->read_disk];
2000 if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
2001 /* ouch - failed to read all of that. */
2002 if (!fix_sync_read_error(r1_bio))
2005 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2006 process_checks(r1_bio);
2011 atomic_set(&r1_bio->remaining, 1);
2012 for (i = 0; i < disks ; i++) {
2013 wbio = r1_bio->bios[i];
2014 if (wbio->bi_end_io == NULL ||
2015 (wbio->bi_end_io == end_sync_read &&
2016 (i == r1_bio->read_disk ||
2017 !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
2020 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2021 wbio->bi_end_io = end_sync_write;
2022 atomic_inc(&r1_bio->remaining);
2023 md_sync_acct(conf->mirrors[i].rdev->bdev, bio_sectors(wbio));
2025 generic_make_request(wbio);
2028 if (atomic_dec_and_test(&r1_bio->remaining)) {
2029 /* if we're here, all write(s) have completed, so clean up */
2030 int s = r1_bio->sectors;
2031 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2032 test_bit(R1BIO_WriteError, &r1_bio->state))
2033 reschedule_retry(r1_bio);
2036 md_done_sync(mddev, s, 1);
2042 * This is a kernel thread which:
2044 * 1. Retries failed read operations on working mirrors.
2045 * 2. Updates the raid superblock when problems encounter.
2046 * 3. Performs writes following reads for array synchronising.
2049 static void fix_read_error(struct r1conf *conf, int read_disk,
2050 sector_t sect, int sectors)
2052 struct mddev *mddev = conf->mddev;
2058 struct md_rdev *rdev;
2060 if (s > (PAGE_SIZE>>9))
2068 rdev = rcu_dereference(conf->mirrors[d].rdev);
2070 (test_bit(In_sync, &rdev->flags) ||
2071 (!test_bit(Faulty, &rdev->flags) &&
2072 rdev->recovery_offset >= sect + s)) &&
2073 is_badblock(rdev, sect, s,
2074 &first_bad, &bad_sectors) == 0) {
2075 atomic_inc(&rdev->nr_pending);
2077 if (sync_page_io(rdev, sect, s<<9,
2078 conf->tmppage, REQ_OP_READ, 0, false))
2080 rdev_dec_pending(rdev, mddev);
2086 if (d == conf->raid_disks * 2)
2088 } while (!success && d != read_disk);
2091 /* Cannot read from anywhere - mark it bad */
2092 struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2093 if (!rdev_set_badblocks(rdev, sect, s, 0))
2094 md_error(mddev, rdev);
2097 /* write it back and re-read */
2099 while (d != read_disk) {
2101 d = conf->raid_disks * 2;
2104 rdev = rcu_dereference(conf->mirrors[d].rdev);
2106 !test_bit(Faulty, &rdev->flags)) {
2107 atomic_inc(&rdev->nr_pending);
2109 r1_sync_page_io(rdev, sect, s,
2110 conf->tmppage, WRITE);
2111 rdev_dec_pending(rdev, mddev);
2116 while (d != read_disk) {
2117 char b[BDEVNAME_SIZE];
2119 d = conf->raid_disks * 2;
2122 rdev = rcu_dereference(conf->mirrors[d].rdev);
2124 !test_bit(Faulty, &rdev->flags)) {
2125 atomic_inc(&rdev->nr_pending);
2127 if (r1_sync_page_io(rdev, sect, s,
2128 conf->tmppage, READ)) {
2129 atomic_add(s, &rdev->corrected_errors);
2130 pr_info("md/raid1:%s: read error corrected (%d sectors at %llu on %s)\n",
2132 (unsigned long long)(sect +
2134 bdevname(rdev->bdev, b));
2136 rdev_dec_pending(rdev, mddev);
2145 static int narrow_write_error(struct r1bio *r1_bio, int i)
2147 struct mddev *mddev = r1_bio->mddev;
2148 struct r1conf *conf = mddev->private;
2149 struct md_rdev *rdev = conf->mirrors[i].rdev;
2151 /* bio has the data to be written to device 'i' where
2152 * we just recently had a write error.
2153 * We repeatedly clone the bio and trim down to one block,
2154 * then try the write. Where the write fails we record
2156 * It is conceivable that the bio doesn't exactly align with
2157 * blocks. We must handle this somehow.
2159 * We currently own a reference on the rdev.
2165 int sect_to_write = r1_bio->sectors;
2168 if (rdev->badblocks.shift < 0)
2171 block_sectors = roundup(1 << rdev->badblocks.shift,
2172 bdev_logical_block_size(rdev->bdev) >> 9);
2173 sector = r1_bio->sector;
2174 sectors = ((sector + block_sectors)
2175 & ~(sector_t)(block_sectors - 1))
2178 while (sect_to_write) {
2180 if (sectors > sect_to_write)
2181 sectors = sect_to_write;
2182 /* Write at 'sector' for 'sectors'*/
2184 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2185 unsigned vcnt = r1_bio->behind_page_count;
2186 struct bio_vec *vec = r1_bio->behind_bvecs;
2188 while (!vec->bv_page) {
2193 wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
2194 memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
2196 wbio->bi_vcnt = vcnt;
2198 wbio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2201 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2202 wbio->bi_iter.bi_sector = r1_bio->sector;
2203 wbio->bi_iter.bi_size = r1_bio->sectors << 9;
2205 bio_trim(wbio, sector - r1_bio->sector, sectors);
2206 wbio->bi_iter.bi_sector += rdev->data_offset;
2207 wbio->bi_bdev = rdev->bdev;
2209 if (submit_bio_wait(wbio) < 0)
2211 ok = rdev_set_badblocks(rdev, sector,
2216 sect_to_write -= sectors;
2218 sectors = block_sectors;
2223 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2226 int s = r1_bio->sectors;
2227 for (m = 0; m < conf->raid_disks * 2 ; m++) {
2228 struct md_rdev *rdev = conf->mirrors[m].rdev;
2229 struct bio *bio = r1_bio->bios[m];
2230 if (bio->bi_end_io == NULL)
2232 if (!bio->bi_error &&
2233 test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2234 rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2236 if (bio->bi_error &&
2237 test_bit(R1BIO_WriteError, &r1_bio->state)) {
2238 if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2239 md_error(conf->mddev, rdev);
2243 md_done_sync(conf->mddev, s, 1);
2246 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2250 for (m = 0; m < conf->raid_disks * 2 ; m++)
2251 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2252 struct md_rdev *rdev = conf->mirrors[m].rdev;
2253 rdev_clear_badblocks(rdev,
2255 r1_bio->sectors, 0);
2256 rdev_dec_pending(rdev, conf->mddev);
2257 } else if (r1_bio->bios[m] != NULL) {
2258 /* This drive got a write error. We need to
2259 * narrow down and record precise write
2263 if (!narrow_write_error(r1_bio, m)) {
2264 md_error(conf->mddev,
2265 conf->mirrors[m].rdev);
2266 /* an I/O failed, we can't clear the bitmap */
2267 set_bit(R1BIO_Degraded, &r1_bio->state);
2269 rdev_dec_pending(conf->mirrors[m].rdev,
2273 spin_lock_irq(&conf->device_lock);
2274 list_add(&r1_bio->retry_list, &conf->bio_end_io_list);
2276 spin_unlock_irq(&conf->device_lock);
2277 md_wakeup_thread(conf->mddev->thread);
2279 if (test_bit(R1BIO_WriteError, &r1_bio->state))
2280 close_write(r1_bio);
2281 raid_end_bio_io(r1_bio);
2285 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2289 struct mddev *mddev = conf->mddev;
2291 char b[BDEVNAME_SIZE];
2292 struct md_rdev *rdev;
2294 clear_bit(R1BIO_ReadError, &r1_bio->state);
2295 /* we got a read error. Maybe the drive is bad. Maybe just
2296 * the block and we can fix it.
2297 * We freeze all other IO, and try reading the block from
2298 * other devices. When we find one, we re-write
2299 * and check it that fixes the read error.
2300 * This is all done synchronously while the array is
2304 bio = r1_bio->bios[r1_bio->read_disk];
2305 bdevname(bio->bi_bdev, b);
2307 r1_bio->bios[r1_bio->read_disk] = NULL;
2309 if (mddev->ro == 0) {
2310 freeze_array(conf, 1);
2311 fix_read_error(conf, r1_bio->read_disk,
2312 r1_bio->sector, r1_bio->sectors);
2313 unfreeze_array(conf);
2315 r1_bio->bios[r1_bio->read_disk] = IO_BLOCKED;
2318 rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
2321 disk = read_balance(conf, r1_bio, &max_sectors);
2323 pr_crit_ratelimited("md/raid1:%s: %s: unrecoverable I/O read error for block %llu\n",
2324 mdname(mddev), b, (unsigned long long)r1_bio->sector);
2325 raid_end_bio_io(r1_bio);
2327 const unsigned long do_sync
2328 = r1_bio->master_bio->bi_opf & REQ_SYNC;
2329 r1_bio->read_disk = disk;
2330 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2331 bio_trim(bio, r1_bio->sector - bio->bi_iter.bi_sector,
2333 r1_bio->bios[r1_bio->read_disk] = bio;
2334 rdev = conf->mirrors[disk].rdev;
2335 pr_info_ratelimited("md/raid1:%s: redirecting sector %llu to other mirror: %s\n",
2337 (unsigned long long)r1_bio->sector,
2338 bdevname(rdev->bdev, b));
2339 bio->bi_iter.bi_sector = r1_bio->sector + rdev->data_offset;
2340 bio->bi_bdev = rdev->bdev;
2341 bio->bi_end_io = raid1_end_read_request;
2342 bio_set_op_attrs(bio, REQ_OP_READ, do_sync);
2343 bio->bi_private = r1_bio;
2344 if (max_sectors < r1_bio->sectors) {
2345 /* Drat - have to split this up more */
2346 struct bio *mbio = r1_bio->master_bio;
2347 int sectors_handled = (r1_bio->sector + max_sectors
2348 - mbio->bi_iter.bi_sector);
2349 r1_bio->sectors = max_sectors;
2350 spin_lock_irq(&conf->device_lock);
2351 if (mbio->bi_phys_segments == 0)
2352 mbio->bi_phys_segments = 2;
2354 mbio->bi_phys_segments++;
2355 spin_unlock_irq(&conf->device_lock);
2356 generic_make_request(bio);
2359 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
2361 r1_bio->master_bio = mbio;
2362 r1_bio->sectors = bio_sectors(mbio) - sectors_handled;
2364 set_bit(R1BIO_ReadError, &r1_bio->state);
2365 r1_bio->mddev = mddev;
2366 r1_bio->sector = mbio->bi_iter.bi_sector +
2371 generic_make_request(bio);
2375 static void raid1d(struct md_thread *thread)
2377 struct mddev *mddev = thread->mddev;
2378 struct r1bio *r1_bio;
2379 unsigned long flags;
2380 struct r1conf *conf = mddev->private;
2381 struct list_head *head = &conf->retry_list;
2382 struct blk_plug plug;
2384 md_check_recovery(mddev);
2386 if (!list_empty_careful(&conf->bio_end_io_list) &&
2387 !test_bit(MD_CHANGE_PENDING, &mddev->flags)) {
2389 spin_lock_irqsave(&conf->device_lock, flags);
2390 if (!test_bit(MD_CHANGE_PENDING, &mddev->flags)) {
2391 while (!list_empty(&conf->bio_end_io_list)) {
2392 list_move(conf->bio_end_io_list.prev, &tmp);
2396 spin_unlock_irqrestore(&conf->device_lock, flags);
2397 while (!list_empty(&tmp)) {
2398 r1_bio = list_first_entry(&tmp, struct r1bio,
2400 list_del(&r1_bio->retry_list);
2401 if (mddev->degraded)
2402 set_bit(R1BIO_Degraded, &r1_bio->state);
2403 if (test_bit(R1BIO_WriteError, &r1_bio->state))
2404 close_write(r1_bio);
2405 raid_end_bio_io(r1_bio);
2409 blk_start_plug(&plug);
2412 flush_pending_writes(conf);
2414 spin_lock_irqsave(&conf->device_lock, flags);
2415 if (list_empty(head)) {
2416 spin_unlock_irqrestore(&conf->device_lock, flags);
2419 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2420 list_del(head->prev);
2422 spin_unlock_irqrestore(&conf->device_lock, flags);
2424 mddev = r1_bio->mddev;
2425 conf = mddev->private;
2426 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2427 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2428 test_bit(R1BIO_WriteError, &r1_bio->state))
2429 handle_sync_write_finished(conf, r1_bio);
2431 sync_request_write(mddev, r1_bio);
2432 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2433 test_bit(R1BIO_WriteError, &r1_bio->state))
2434 handle_write_finished(conf, r1_bio);
2435 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2436 handle_read_error(conf, r1_bio);
2438 /* just a partial read to be scheduled from separate
2441 generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2444 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2445 md_check_recovery(mddev);
2447 blk_finish_plug(&plug);
2450 static int init_resync(struct r1conf *conf)
2454 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2455 BUG_ON(conf->r1buf_pool);
2456 conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2458 if (!conf->r1buf_pool)
2460 conf->next_resync = 0;
2465 * perform a "sync" on one "block"
2467 * We need to make sure that no normal I/O request - particularly write
2468 * requests - conflict with active sync requests.
2470 * This is achieved by tracking pending requests and a 'barrier' concept
2471 * that can be installed to exclude normal IO requests.
2474 static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
2477 struct r1conf *conf = mddev->private;
2478 struct r1bio *r1_bio;
2480 sector_t max_sector, nr_sectors;
2484 int write_targets = 0, read_targets = 0;
2485 sector_t sync_blocks;
2486 int still_degraded = 0;
2487 int good_sectors = RESYNC_SECTORS;
2488 int min_bad = 0; /* number of sectors that are bad in all devices */
2490 if (!conf->r1buf_pool)
2491 if (init_resync(conf))
2494 max_sector = mddev->dev_sectors;
2495 if (sector_nr >= max_sector) {
2496 /* If we aborted, we need to abort the
2497 * sync on the 'current' bitmap chunk (there will
2498 * only be one in raid1 resync.
2499 * We can find the current addess in mddev->curr_resync
2501 if (mddev->curr_resync < max_sector) /* aborted */
2502 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2504 else /* completed sync */
2507 bitmap_close_sync(mddev->bitmap);
2510 if (mddev_is_clustered(mddev)) {
2511 conf->cluster_sync_low = 0;
2512 conf->cluster_sync_high = 0;
2517 if (mddev->bitmap == NULL &&
2518 mddev->recovery_cp == MaxSector &&
2519 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2520 conf->fullsync == 0) {
2522 return max_sector - sector_nr;
2524 /* before building a request, check if we can skip these blocks..
2525 * This call the bitmap_start_sync doesn't actually record anything
2527 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2528 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2529 /* We can skip this block, and probably several more */
2535 * If there is non-resync activity waiting for a turn, then let it
2536 * though before starting on this new sync request.
2538 if (conf->nr_waiting)
2539 schedule_timeout_uninterruptible(1);
2541 /* we are incrementing sector_nr below. To be safe, we check against
2542 * sector_nr + two times RESYNC_SECTORS
2545 bitmap_cond_end_sync(mddev->bitmap, sector_nr,
2546 mddev_is_clustered(mddev) && (sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
2547 r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2549 raise_barrier(conf, sector_nr);
2553 * If we get a correctably read error during resync or recovery,
2554 * we might want to read from a different device. So we
2555 * flag all drives that could conceivably be read from for READ,
2556 * and any others (which will be non-In_sync devices) for WRITE.
2557 * If a read fails, we try reading from something else for which READ
2561 r1_bio->mddev = mddev;
2562 r1_bio->sector = sector_nr;
2564 set_bit(R1BIO_IsSync, &r1_bio->state);
2566 for (i = 0; i < conf->raid_disks * 2; i++) {
2567 struct md_rdev *rdev;
2568 bio = r1_bio->bios[i];
2571 rdev = rcu_dereference(conf->mirrors[i].rdev);
2573 test_bit(Faulty, &rdev->flags)) {
2574 if (i < conf->raid_disks)
2576 } else if (!test_bit(In_sync, &rdev->flags)) {
2577 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2578 bio->bi_end_io = end_sync_write;
2581 /* may need to read from here */
2582 sector_t first_bad = MaxSector;
2585 if (is_badblock(rdev, sector_nr, good_sectors,
2586 &first_bad, &bad_sectors)) {
2587 if (first_bad > sector_nr)
2588 good_sectors = first_bad - sector_nr;
2590 bad_sectors -= (sector_nr - first_bad);
2592 min_bad > bad_sectors)
2593 min_bad = bad_sectors;
2596 if (sector_nr < first_bad) {
2597 if (test_bit(WriteMostly, &rdev->flags)) {
2604 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2605 bio->bi_end_io = end_sync_read;
2607 } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2608 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2609 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2611 * The device is suitable for reading (InSync),
2612 * but has bad block(s) here. Let's try to correct them,
2613 * if we are doing resync or repair. Otherwise, leave
2614 * this device alone for this sync request.
2616 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2617 bio->bi_end_io = end_sync_write;
2621 if (bio->bi_end_io) {
2622 atomic_inc(&rdev->nr_pending);
2623 bio->bi_iter.bi_sector = sector_nr + rdev->data_offset;
2624 bio->bi_bdev = rdev->bdev;
2625 bio->bi_private = r1_bio;
2631 r1_bio->read_disk = disk;
2633 if (read_targets == 0 && min_bad > 0) {
2634 /* These sectors are bad on all InSync devices, so we
2635 * need to mark them bad on all write targets
2638 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2639 if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2640 struct md_rdev *rdev = conf->mirrors[i].rdev;
2641 ok = rdev_set_badblocks(rdev, sector_nr,
2645 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2650 /* Cannot record the badblocks, so need to
2652 * If there are multiple read targets, could just
2653 * fail the really bad ones ???
2655 conf->recovery_disabled = mddev->recovery_disabled;
2656 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2662 if (min_bad > 0 && min_bad < good_sectors) {
2663 /* only resync enough to reach the next bad->good
2665 good_sectors = min_bad;
2668 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2669 /* extra read targets are also write targets */
2670 write_targets += read_targets-1;
2672 if (write_targets == 0 || read_targets == 0) {
2673 /* There is nowhere to write, so all non-sync
2674 * drives must be failed - so we are finished
2678 max_sector = sector_nr + min_bad;
2679 rv = max_sector - sector_nr;
2685 if (max_sector > mddev->resync_max)
2686 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2687 if (max_sector > sector_nr + good_sectors)
2688 max_sector = sector_nr + good_sectors;
2693 int len = PAGE_SIZE;
2694 if (sector_nr + (len>>9) > max_sector)
2695 len = (max_sector - sector_nr) << 9;
2698 if (sync_blocks == 0) {
2699 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2700 &sync_blocks, still_degraded) &&
2702 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2704 if ((len >> 9) > sync_blocks)
2705 len = sync_blocks<<9;
2708 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2709 bio = r1_bio->bios[i];
2710 if (bio->bi_end_io) {
2711 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2712 if (bio_add_page(bio, page, len, 0) == 0) {
2714 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2717 bio = r1_bio->bios[i];
2718 if (bio->bi_end_io==NULL)
2720 /* remove last page from this bio */
2722 bio->bi_iter.bi_size -= len;
2723 bio_clear_flag(bio, BIO_SEG_VALID);
2729 nr_sectors += len>>9;
2730 sector_nr += len>>9;
2731 sync_blocks -= (len>>9);
2732 } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2734 r1_bio->sectors = nr_sectors;
2736 if (mddev_is_clustered(mddev) &&
2737 conf->cluster_sync_high < sector_nr + nr_sectors) {
2738 conf->cluster_sync_low = mddev->curr_resync_completed;
2739 conf->cluster_sync_high = conf->cluster_sync_low + CLUSTER_RESYNC_WINDOW_SECTORS;
2740 /* Send resync message */
2741 md_cluster_ops->resync_info_update(mddev,
2742 conf->cluster_sync_low,
2743 conf->cluster_sync_high);
2746 /* For a user-requested sync, we read all readable devices and do a
2749 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2750 atomic_set(&r1_bio->remaining, read_targets);
2751 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2752 bio = r1_bio->bios[i];
2753 if (bio->bi_end_io == end_sync_read) {
2755 md_sync_acct(bio->bi_bdev, nr_sectors);
2756 generic_make_request(bio);
2760 atomic_set(&r1_bio->remaining, 1);
2761 bio = r1_bio->bios[r1_bio->read_disk];
2762 md_sync_acct(bio->bi_bdev, nr_sectors);
2763 generic_make_request(bio);
2769 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2774 return mddev->dev_sectors;
2777 static struct r1conf *setup_conf(struct mddev *mddev)
2779 struct r1conf *conf;
2781 struct raid1_info *disk;
2782 struct md_rdev *rdev;
2785 conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2789 conf->mirrors = kzalloc(sizeof(struct raid1_info)
2790 * mddev->raid_disks * 2,
2795 conf->tmppage = alloc_page(GFP_KERNEL);
2799 conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2800 if (!conf->poolinfo)
2802 conf->poolinfo->raid_disks = mddev->raid_disks * 2;
2803 conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2806 if (!conf->r1bio_pool)
2809 conf->poolinfo->mddev = mddev;
2812 spin_lock_init(&conf->device_lock);
2813 rdev_for_each(rdev, mddev) {
2814 struct request_queue *q;
2815 int disk_idx = rdev->raid_disk;
2816 if (disk_idx >= mddev->raid_disks
2819 if (test_bit(Replacement, &rdev->flags))
2820 disk = conf->mirrors + mddev->raid_disks + disk_idx;
2822 disk = conf->mirrors + disk_idx;
2827 q = bdev_get_queue(rdev->bdev);
2829 disk->head_position = 0;
2830 disk->seq_start = MaxSector;
2832 conf->raid_disks = mddev->raid_disks;
2833 conf->mddev = mddev;
2834 INIT_LIST_HEAD(&conf->retry_list);
2835 INIT_LIST_HEAD(&conf->bio_end_io_list);
2837 spin_lock_init(&conf->resync_lock);
2838 init_waitqueue_head(&conf->wait_barrier);
2840 bio_list_init(&conf->pending_bio_list);
2841 conf->pending_count = 0;
2842 conf->recovery_disabled = mddev->recovery_disabled - 1;
2844 conf->start_next_window = MaxSector;
2845 conf->current_window_requests = conf->next_window_requests = 0;
2848 for (i = 0; i < conf->raid_disks * 2; i++) {
2850 disk = conf->mirrors + i;
2852 if (i < conf->raid_disks &&
2853 disk[conf->raid_disks].rdev) {
2854 /* This slot has a replacement. */
2856 /* No original, just make the replacement
2857 * a recovering spare
2860 disk[conf->raid_disks].rdev;
2861 disk[conf->raid_disks].rdev = NULL;
2862 } else if (!test_bit(In_sync, &disk->rdev->flags))
2863 /* Original is not in_sync - bad */
2868 !test_bit(In_sync, &disk->rdev->flags)) {
2869 disk->head_position = 0;
2871 (disk->rdev->saved_raid_disk < 0))
2877 conf->thread = md_register_thread(raid1d, mddev, "raid1");
2885 mempool_destroy(conf->r1bio_pool);
2886 kfree(conf->mirrors);
2887 safe_put_page(conf->tmppage);
2888 kfree(conf->poolinfo);
2891 return ERR_PTR(err);
2894 static void raid1_free(struct mddev *mddev, void *priv);
2895 static int raid1_run(struct mddev *mddev)
2897 struct r1conf *conf;
2899 struct md_rdev *rdev;
2901 bool discard_supported = false;
2903 if (mddev->level != 1) {
2904 pr_warn("md/raid1:%s: raid level not set to mirroring (%d)\n",
2905 mdname(mddev), mddev->level);
2908 if (mddev->reshape_position != MaxSector) {
2909 pr_warn("md/raid1:%s: reshape_position set but not supported\n",
2914 * copy the already verified devices into our private RAID1
2915 * bookkeeping area. [whatever we allocate in run(),
2916 * should be freed in raid1_free()]
2918 if (mddev->private == NULL)
2919 conf = setup_conf(mddev);
2921 conf = mddev->private;
2924 return PTR_ERR(conf);
2927 blk_queue_max_write_same_sectors(mddev->queue, 0);
2929 rdev_for_each(rdev, mddev) {
2930 if (!mddev->gendisk)
2932 disk_stack_limits(mddev->gendisk, rdev->bdev,
2933 rdev->data_offset << 9);
2934 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
2935 discard_supported = true;
2938 mddev->degraded = 0;
2939 for (i=0; i < conf->raid_disks; i++)
2940 if (conf->mirrors[i].rdev == NULL ||
2941 !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2942 test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2945 if (conf->raid_disks - mddev->degraded == 1)
2946 mddev->recovery_cp = MaxSector;
2948 if (mddev->recovery_cp != MaxSector)
2949 pr_info("md/raid1:%s: not clean -- starting background reconstruction\n",
2951 pr_info("md/raid1:%s: active with %d out of %d mirrors\n",
2952 mdname(mddev), mddev->raid_disks - mddev->degraded,
2956 * Ok, everything is just fine now
2958 mddev->thread = conf->thread;
2959 conf->thread = NULL;
2960 mddev->private = conf;
2962 md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2965 if (discard_supported)
2966 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
2969 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
2973 ret = md_integrity_register(mddev);
2975 md_unregister_thread(&mddev->thread);
2976 raid1_free(mddev, conf);
2981 static void raid1_free(struct mddev *mddev, void *priv)
2983 struct r1conf *conf = priv;
2985 mempool_destroy(conf->r1bio_pool);
2986 kfree(conf->mirrors);
2987 safe_put_page(conf->tmppage);
2988 kfree(conf->poolinfo);
2992 static int raid1_resize(struct mddev *mddev, sector_t sectors)
2994 /* no resync is happening, and there is enough space
2995 * on all devices, so we can resize.
2996 * We need to make sure resync covers any new space.
2997 * If the array is shrinking we should possibly wait until
2998 * any io in the removed space completes, but it hardly seems
3001 sector_t newsize = raid1_size(mddev, sectors, 0);
3002 if (mddev->external_size &&
3003 mddev->array_sectors > newsize)
3005 if (mddev->bitmap) {
3006 int ret = bitmap_resize(mddev->bitmap, newsize, 0, 0);
3010 md_set_array_sectors(mddev, newsize);
3011 set_capacity(mddev->gendisk, mddev->array_sectors);
3012 revalidate_disk(mddev->gendisk);
3013 if (sectors > mddev->dev_sectors &&
3014 mddev->recovery_cp > mddev->dev_sectors) {
3015 mddev->recovery_cp = mddev->dev_sectors;
3016 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3018 mddev->dev_sectors = sectors;
3019 mddev->resync_max_sectors = sectors;
3023 static int raid1_reshape(struct mddev *mddev)
3026 * 1/ resize the r1bio_pool
3027 * 2/ resize conf->mirrors
3029 * We allocate a new r1bio_pool if we can.
3030 * Then raise a device barrier and wait until all IO stops.
3031 * Then resize conf->mirrors and swap in the new r1bio pool.
3033 * At the same time, we "pack" the devices so that all the missing
3034 * devices have the higher raid_disk numbers.
3036 mempool_t *newpool, *oldpool;
3037 struct pool_info *newpoolinfo;
3038 struct raid1_info *newmirrors;
3039 struct r1conf *conf = mddev->private;
3040 int cnt, raid_disks;
3041 unsigned long flags;
3044 /* Cannot change chunk_size, layout, or level */
3045 if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
3046 mddev->layout != mddev->new_layout ||
3047 mddev->level != mddev->new_level) {
3048 mddev->new_chunk_sectors = mddev->chunk_sectors;
3049 mddev->new_layout = mddev->layout;
3050 mddev->new_level = mddev->level;
3054 if (!mddev_is_clustered(mddev)) {
3055 err = md_allow_write(mddev);
3060 raid_disks = mddev->raid_disks + mddev->delta_disks;
3062 if (raid_disks < conf->raid_disks) {
3064 for (d= 0; d < conf->raid_disks; d++)
3065 if (conf->mirrors[d].rdev)
3067 if (cnt > raid_disks)
3071 newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
3074 newpoolinfo->mddev = mddev;
3075 newpoolinfo->raid_disks = raid_disks * 2;
3077 newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
3078 r1bio_pool_free, newpoolinfo);
3083 newmirrors = kzalloc(sizeof(struct raid1_info) * raid_disks * 2,
3087 mempool_destroy(newpool);
3091 freeze_array(conf, 0);
3093 /* ok, everything is stopped */
3094 oldpool = conf->r1bio_pool;
3095 conf->r1bio_pool = newpool;
3097 for (d = d2 = 0; d < conf->raid_disks; d++) {
3098 struct md_rdev *rdev = conf->mirrors[d].rdev;
3099 if (rdev && rdev->raid_disk != d2) {
3100 sysfs_unlink_rdev(mddev, rdev);
3101 rdev->raid_disk = d2;
3102 sysfs_unlink_rdev(mddev, rdev);
3103 if (sysfs_link_rdev(mddev, rdev))
3104 pr_warn("md/raid1:%s: cannot register rd%d\n",
3105 mdname(mddev), rdev->raid_disk);
3108 newmirrors[d2++].rdev = rdev;
3110 kfree(conf->mirrors);
3111 conf->mirrors = newmirrors;
3112 kfree(conf->poolinfo);
3113 conf->poolinfo = newpoolinfo;
3115 spin_lock_irqsave(&conf->device_lock, flags);
3116 mddev->degraded += (raid_disks - conf->raid_disks);
3117 spin_unlock_irqrestore(&conf->device_lock, flags);
3118 conf->raid_disks = mddev->raid_disks = raid_disks;
3119 mddev->delta_disks = 0;
3121 unfreeze_array(conf);
3123 set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3124 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3125 md_wakeup_thread(mddev->thread);
3127 mempool_destroy(oldpool);
3131 static void raid1_quiesce(struct mddev *mddev, int state)
3133 struct r1conf *conf = mddev->private;
3136 case 2: /* wake for suspend */
3137 wake_up(&conf->wait_barrier);
3140 freeze_array(conf, 0);
3143 unfreeze_array(conf);
3148 static void *raid1_takeover(struct mddev *mddev)
3150 /* raid1 can take over:
3151 * raid5 with 2 devices, any layout or chunk size
3153 if (mddev->level == 5 && mddev->raid_disks == 2) {
3154 struct r1conf *conf;
3155 mddev->new_level = 1;
3156 mddev->new_layout = 0;
3157 mddev->new_chunk_sectors = 0;
3158 conf = setup_conf(mddev);
3160 /* Array must appear to be quiesced */
3161 conf->array_frozen = 1;
3164 return ERR_PTR(-EINVAL);
3167 static struct md_personality raid1_personality =
3171 .owner = THIS_MODULE,
3172 .make_request = raid1_make_request,
3175 .status = raid1_status,
3176 .error_handler = raid1_error,
3177 .hot_add_disk = raid1_add_disk,
3178 .hot_remove_disk= raid1_remove_disk,
3179 .spare_active = raid1_spare_active,
3180 .sync_request = raid1_sync_request,
3181 .resize = raid1_resize,
3183 .check_reshape = raid1_reshape,
3184 .quiesce = raid1_quiesce,
3185 .takeover = raid1_takeover,
3186 .congested = raid1_congested,
3189 static int __init raid_init(void)
3191 return register_md_personality(&raid1_personality);
3194 static void raid_exit(void)
3196 unregister_md_personality(&raid1_personality);
3199 module_init(raid_init);
3200 module_exit(raid_exit);
3201 MODULE_LICENSE("GPL");
3202 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3203 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3204 MODULE_ALIAS("md-raid1");
3205 MODULE_ALIAS("md-level-1");
3207 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);