2 * raid10.c : Multiple Devices driver for Linux
4 * Copyright (C) 2000-2004 Neil Brown
6 * RAID-10 support for md.
8 * Base on code in raid1.c. See raid1.c for further copyright information.
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)
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.
21 #include <linux/slab.h>
22 #include <linux/delay.h>
23 #include <linux/blkdev.h>
24 #include <linux/seq_file.h>
25 #include <linux/ratelimit.h>
32 * RAID10 provides a combination of RAID0 and RAID1 functionality.
33 * The layout of data is defined by
36 * near_copies (stored in low byte of layout)
37 * far_copies (stored in second byte of layout)
38 * far_offset (stored in bit 16 of layout )
40 * The data to be stored is divided into chunks using chunksize.
41 * Each device is divided into far_copies sections.
42 * In each section, chunks are laid out in a style similar to raid0, but
43 * near_copies copies of each chunk is stored (each on a different drive).
44 * The starting device for each section is offset near_copies from the starting
45 * device of the previous section.
46 * Thus they are (near_copies*far_copies) of each chunk, and each is on a different
48 * near_copies and far_copies must be at least one, and their product is at most
51 * If far_offset is true, then the far_copies are handled a bit differently.
52 * The copies are still in different stripes, but instead of be very far apart
53 * on disk, there are adjacent stripes.
57 * Number of guaranteed r10bios in case of extreme VM load:
59 #define NR_RAID10_BIOS 256
61 static void allow_barrier(conf_t *conf);
62 static void lower_barrier(conf_t *conf);
64 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
67 int size = offsetof(struct r10bio_s, devs[conf->copies]);
69 /* allocate a r10bio with room for raid_disks entries in the bios array */
70 return kzalloc(size, gfp_flags);
73 static void r10bio_pool_free(void *r10_bio, void *data)
78 /* Maximum size of each resync request */
79 #define RESYNC_BLOCK_SIZE (64*1024)
80 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
81 /* amount of memory to reserve for resync requests */
82 #define RESYNC_WINDOW (1024*1024)
83 /* maximum number of concurrent requests, memory permitting */
84 #define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
87 * When performing a resync, we need to read and compare, so
88 * we need as many pages are there are copies.
89 * When performing a recovery, we need 2 bios, one for read,
90 * one for write (we recover only one drive per r10buf)
93 static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
102 r10_bio = r10bio_pool_alloc(gfp_flags, conf);
106 if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
107 nalloc = conf->copies; /* resync */
109 nalloc = 2; /* recovery */
114 for (j = nalloc ; j-- ; ) {
115 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
118 r10_bio->devs[j].bio = bio;
121 * Allocate RESYNC_PAGES data pages and attach them
124 for (j = 0 ; j < nalloc; j++) {
125 bio = r10_bio->devs[j].bio;
126 for (i = 0; i < RESYNC_PAGES; i++) {
127 if (j == 1 && !test_bit(MD_RECOVERY_SYNC,
128 &conf->mddev->recovery)) {
129 /* we can share bv_page's during recovery */
130 struct bio *rbio = r10_bio->devs[0].bio;
131 page = rbio->bi_io_vec[i].bv_page;
134 page = alloc_page(gfp_flags);
138 bio->bi_io_vec[i].bv_page = page;
146 safe_put_page(bio->bi_io_vec[i-1].bv_page);
148 for (i = 0; i < RESYNC_PAGES ; i++)
149 safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
152 while ( ++j < nalloc )
153 bio_put(r10_bio->devs[j].bio);
154 r10bio_pool_free(r10_bio, conf);
158 static void r10buf_pool_free(void *__r10_bio, void *data)
162 r10bio_t *r10bio = __r10_bio;
165 for (j=0; j < conf->copies; j++) {
166 struct bio *bio = r10bio->devs[j].bio;
168 for (i = 0; i < RESYNC_PAGES; i++) {
169 safe_put_page(bio->bi_io_vec[i].bv_page);
170 bio->bi_io_vec[i].bv_page = NULL;
175 r10bio_pool_free(r10bio, conf);
178 static void put_all_bios(conf_t *conf, r10bio_t *r10_bio)
182 for (i = 0; i < conf->copies; i++) {
183 struct bio **bio = & r10_bio->devs[i].bio;
184 if (*bio && *bio != IO_BLOCKED)
190 static void free_r10bio(r10bio_t *r10_bio)
192 conf_t *conf = r10_bio->mddev->private;
194 put_all_bios(conf, r10_bio);
195 mempool_free(r10_bio, conf->r10bio_pool);
198 static void put_buf(r10bio_t *r10_bio)
200 conf_t *conf = r10_bio->mddev->private;
202 mempool_free(r10_bio, conf->r10buf_pool);
207 static void reschedule_retry(r10bio_t *r10_bio)
210 mddev_t *mddev = r10_bio->mddev;
211 conf_t *conf = mddev->private;
213 spin_lock_irqsave(&conf->device_lock, flags);
214 list_add(&r10_bio->retry_list, &conf->retry_list);
216 spin_unlock_irqrestore(&conf->device_lock, flags);
218 /* wake up frozen array... */
219 wake_up(&conf->wait_barrier);
221 md_wakeup_thread(mddev->thread);
225 * raid_end_bio_io() is called when we have finished servicing a mirrored
226 * operation and are ready to return a success/failure code to the buffer
229 static void raid_end_bio_io(r10bio_t *r10_bio)
231 struct bio *bio = r10_bio->master_bio;
233 conf_t *conf = r10_bio->mddev->private;
235 if (bio->bi_phys_segments) {
237 spin_lock_irqsave(&conf->device_lock, flags);
238 bio->bi_phys_segments--;
239 done = (bio->bi_phys_segments == 0);
240 spin_unlock_irqrestore(&conf->device_lock, flags);
243 if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
244 clear_bit(BIO_UPTODATE, &bio->bi_flags);
248 * Wake up any possible resync thread that waits for the device
253 free_r10bio(r10_bio);
257 * Update disk head position estimator based on IRQ completion info.
259 static inline void update_head_pos(int slot, r10bio_t *r10_bio)
261 conf_t *conf = r10_bio->mddev->private;
263 conf->mirrors[r10_bio->devs[slot].devnum].head_position =
264 r10_bio->devs[slot].addr + (r10_bio->sectors);
268 * Find the disk number which triggered given bio
270 static int find_bio_disk(conf_t *conf, r10bio_t *r10_bio, struct bio *bio)
274 for (slot = 0; slot < conf->copies; slot++)
275 if (r10_bio->devs[slot].bio == bio)
278 BUG_ON(slot == conf->copies);
279 update_head_pos(slot, r10_bio);
281 return r10_bio->devs[slot].devnum;
284 static void raid10_end_read_request(struct bio *bio, int error)
286 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
287 r10bio_t *r10_bio = bio->bi_private;
289 conf_t *conf = r10_bio->mddev->private;
292 slot = r10_bio->read_slot;
293 dev = r10_bio->devs[slot].devnum;
295 * this branch is our 'one mirror IO has finished' event handler:
297 update_head_pos(slot, r10_bio);
301 * Set R10BIO_Uptodate in our master bio, so that
302 * we will return a good error code to the higher
303 * levels even if IO on some other mirrored buffer fails.
305 * The 'master' represents the composite IO operation to
306 * user-side. So if something waits for IO, then it will
307 * wait for the 'master' bio.
309 set_bit(R10BIO_Uptodate, &r10_bio->state);
310 raid_end_bio_io(r10_bio);
311 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
314 * oops, read error - keep the refcount on the rdev
316 char b[BDEVNAME_SIZE];
317 printk_ratelimited(KERN_ERR
318 "md/raid10:%s: %s: rescheduling sector %llu\n",
320 bdevname(conf->mirrors[dev].rdev->bdev, b),
321 (unsigned long long)r10_bio->sector);
322 set_bit(R10BIO_ReadError, &r10_bio->state);
323 reschedule_retry(r10_bio);
327 static void raid10_end_write_request(struct bio *bio, int error)
329 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
330 r10bio_t *r10_bio = bio->bi_private;
332 conf_t *conf = r10_bio->mddev->private;
334 dev = find_bio_disk(conf, r10_bio, bio);
337 * this branch is our 'one mirror IO has finished' event handler:
340 md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
341 /* an I/O failed, we can't clear the bitmap */
342 set_bit(R10BIO_Degraded, &r10_bio->state);
345 * Set R10BIO_Uptodate in our master bio, so that
346 * we will return a good error code for to the higher
347 * levels even if IO on some other mirrored buffer fails.
349 * The 'master' represents the composite IO operation to
350 * user-side. So if something waits for IO, then it will
351 * wait for the 'master' bio.
353 set_bit(R10BIO_Uptodate, &r10_bio->state);
357 * Let's see if all mirrored write operations have finished
360 if (atomic_dec_and_test(&r10_bio->remaining)) {
361 /* clear the bitmap if all writes complete successfully */
362 bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
364 !test_bit(R10BIO_Degraded, &r10_bio->state),
366 md_write_end(r10_bio->mddev);
367 raid_end_bio_io(r10_bio);
370 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
375 * RAID10 layout manager
376 * As well as the chunksize and raid_disks count, there are two
377 * parameters: near_copies and far_copies.
378 * near_copies * far_copies must be <= raid_disks.
379 * Normally one of these will be 1.
380 * If both are 1, we get raid0.
381 * If near_copies == raid_disks, we get raid1.
383 * Chunks are laid out in raid0 style with near_copies copies of the
384 * first chunk, followed by near_copies copies of the next chunk and
386 * If far_copies > 1, then after 1/far_copies of the array has been assigned
387 * as described above, we start again with a device offset of near_copies.
388 * So we effectively have another copy of the whole array further down all
389 * the drives, but with blocks on different drives.
390 * With this layout, and block is never stored twice on the one device.
392 * raid10_find_phys finds the sector offset of a given virtual sector
393 * on each device that it is on.
395 * raid10_find_virt does the reverse mapping, from a device and a
396 * sector offset to a virtual address
399 static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio)
409 /* now calculate first sector/dev */
410 chunk = r10bio->sector >> conf->chunk_shift;
411 sector = r10bio->sector & conf->chunk_mask;
413 chunk *= conf->near_copies;
415 dev = sector_div(stripe, conf->raid_disks);
416 if (conf->far_offset)
417 stripe *= conf->far_copies;
419 sector += stripe << conf->chunk_shift;
421 /* and calculate all the others */
422 for (n=0; n < conf->near_copies; n++) {
425 r10bio->devs[slot].addr = sector;
426 r10bio->devs[slot].devnum = d;
429 for (f = 1; f < conf->far_copies; f++) {
430 d += conf->near_copies;
431 if (d >= conf->raid_disks)
432 d -= conf->raid_disks;
434 r10bio->devs[slot].devnum = d;
435 r10bio->devs[slot].addr = s;
439 if (dev >= conf->raid_disks) {
441 sector += (conf->chunk_mask + 1);
444 BUG_ON(slot != conf->copies);
447 static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev)
449 sector_t offset, chunk, vchunk;
451 offset = sector & conf->chunk_mask;
452 if (conf->far_offset) {
454 chunk = sector >> conf->chunk_shift;
455 fc = sector_div(chunk, conf->far_copies);
456 dev -= fc * conf->near_copies;
458 dev += conf->raid_disks;
460 while (sector >= conf->stride) {
461 sector -= conf->stride;
462 if (dev < conf->near_copies)
463 dev += conf->raid_disks - conf->near_copies;
465 dev -= conf->near_copies;
467 chunk = sector >> conf->chunk_shift;
469 vchunk = chunk * conf->raid_disks + dev;
470 sector_div(vchunk, conf->near_copies);
471 return (vchunk << conf->chunk_shift) + offset;
475 * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
477 * @bvm: properties of new bio
478 * @biovec: the request that could be merged to it.
480 * Return amount of bytes we can accept at this offset
481 * If near_copies == raid_disk, there are no striping issues,
482 * but in that case, the function isn't called at all.
484 static int raid10_mergeable_bvec(struct request_queue *q,
485 struct bvec_merge_data *bvm,
486 struct bio_vec *biovec)
488 mddev_t *mddev = q->queuedata;
489 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
491 unsigned int chunk_sectors = mddev->chunk_sectors;
492 unsigned int bio_sectors = bvm->bi_size >> 9;
494 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
495 if (max < 0) max = 0; /* bio_add cannot handle a negative return */
496 if (max <= biovec->bv_len && bio_sectors == 0)
497 return biovec->bv_len;
503 * This routine returns the disk from which the requested read should
504 * be done. There is a per-array 'next expected sequential IO' sector
505 * number - if this matches on the next IO then we use the last disk.
506 * There is also a per-disk 'last know head position' sector that is
507 * maintained from IRQ contexts, both the normal and the resync IO
508 * completion handlers update this position correctly. If there is no
509 * perfect sequential match then we pick the disk whose head is closest.
511 * If there are 2 mirrors in the same 2 devices, performance degrades
512 * because position is mirror, not device based.
514 * The rdev for the device selected will have nr_pending incremented.
518 * FIXME: possibly should rethink readbalancing and do it differently
519 * depending on near_copies / far_copies geometry.
521 static int read_balance(conf_t *conf, r10bio_t *r10_bio, int *max_sectors)
523 const sector_t this_sector = r10_bio->sector;
525 int sectors = r10_bio->sectors;
526 int best_good_sectors;
527 sector_t new_distance, best_dist;
532 raid10_find_phys(conf, r10_bio);
535 sectors = r10_bio->sectors;
537 best_dist = MaxSector;
538 best_good_sectors = 0;
541 * Check if we can balance. We can balance on the whole
542 * device if no resync is going on (recovery is ok), or below
543 * the resync window. We take the first readable disk when
544 * above the resync window.
546 if (conf->mddev->recovery_cp < MaxSector
547 && (this_sector + sectors >= conf->next_resync))
550 for (slot = 0; slot < conf->copies ; slot++) {
555 if (r10_bio->devs[slot].bio == IO_BLOCKED)
557 disk = r10_bio->devs[slot].devnum;
558 rdev = rcu_dereference(conf->mirrors[disk].rdev);
561 if (!test_bit(In_sync, &rdev->flags))
564 dev_sector = r10_bio->devs[slot].addr;
565 if (is_badblock(rdev, dev_sector, sectors,
566 &first_bad, &bad_sectors)) {
567 if (best_dist < MaxSector)
568 /* Already have a better slot */
570 if (first_bad <= dev_sector) {
571 /* Cannot read here. If this is the
572 * 'primary' device, then we must not read
573 * beyond 'bad_sectors' from another device.
575 bad_sectors -= (dev_sector - first_bad);
576 if (!do_balance && sectors > bad_sectors)
577 sectors = bad_sectors;
578 if (best_good_sectors > sectors)
579 best_good_sectors = sectors;
581 sector_t good_sectors =
582 first_bad - dev_sector;
583 if (good_sectors > best_good_sectors) {
584 best_good_sectors = good_sectors;
588 /* Must read from here */
593 best_good_sectors = sectors;
598 /* This optimisation is debatable, and completely destroys
599 * sequential read speed for 'far copies' arrays. So only
600 * keep it for 'near' arrays, and review those later.
602 if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending))
605 /* for far > 1 always use the lowest address */
606 if (conf->far_copies > 1)
607 new_distance = r10_bio->devs[slot].addr;
609 new_distance = abs(r10_bio->devs[slot].addr -
610 conf->mirrors[disk].head_position);
611 if (new_distance < best_dist) {
612 best_dist = new_distance;
616 if (slot == conf->copies)
620 disk = r10_bio->devs[slot].devnum;
621 rdev = rcu_dereference(conf->mirrors[disk].rdev);
624 atomic_inc(&rdev->nr_pending);
625 if (test_bit(Faulty, &rdev->flags)) {
626 /* Cannot risk returning a device that failed
627 * before we inc'ed nr_pending
629 rdev_dec_pending(rdev, conf->mddev);
632 r10_bio->read_slot = slot;
636 *max_sectors = best_good_sectors;
641 static int raid10_congested(void *data, int bits)
643 mddev_t *mddev = data;
644 conf_t *conf = mddev->private;
647 if (mddev_congested(mddev, bits))
650 for (i = 0; i < conf->raid_disks && ret == 0; i++) {
651 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
652 if (rdev && !test_bit(Faulty, &rdev->flags)) {
653 struct request_queue *q = bdev_get_queue(rdev->bdev);
655 ret |= bdi_congested(&q->backing_dev_info, bits);
662 static void flush_pending_writes(conf_t *conf)
664 /* Any writes that have been queued but are awaiting
665 * bitmap updates get flushed here.
667 spin_lock_irq(&conf->device_lock);
669 if (conf->pending_bio_list.head) {
671 bio = bio_list_get(&conf->pending_bio_list);
672 spin_unlock_irq(&conf->device_lock);
673 /* flush any pending bitmap writes to disk
674 * before proceeding w/ I/O */
675 bitmap_unplug(conf->mddev->bitmap);
677 while (bio) { /* submit pending writes */
678 struct bio *next = bio->bi_next;
680 generic_make_request(bio);
684 spin_unlock_irq(&conf->device_lock);
688 * Sometimes we need to suspend IO while we do something else,
689 * either some resync/recovery, or reconfigure the array.
690 * To do this we raise a 'barrier'.
691 * The 'barrier' is a counter that can be raised multiple times
692 * to count how many activities are happening which preclude
694 * We can only raise the barrier if there is no pending IO.
695 * i.e. if nr_pending == 0.
696 * We choose only to raise the barrier if no-one is waiting for the
697 * barrier to go down. This means that as soon as an IO request
698 * is ready, no other operations which require a barrier will start
699 * until the IO request has had a chance.
701 * So: regular IO calls 'wait_barrier'. When that returns there
702 * is no backgroup IO happening, It must arrange to call
703 * allow_barrier when it has finished its IO.
704 * backgroup IO calls must call raise_barrier. Once that returns
705 * there is no normal IO happeing. It must arrange to call
706 * lower_barrier when the particular background IO completes.
709 static void raise_barrier(conf_t *conf, int force)
711 BUG_ON(force && !conf->barrier);
712 spin_lock_irq(&conf->resync_lock);
714 /* Wait until no block IO is waiting (unless 'force') */
715 wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
716 conf->resync_lock, );
718 /* block any new IO from starting */
721 /* Now wait for all pending IO to complete */
722 wait_event_lock_irq(conf->wait_barrier,
723 !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
724 conf->resync_lock, );
726 spin_unlock_irq(&conf->resync_lock);
729 static void lower_barrier(conf_t *conf)
732 spin_lock_irqsave(&conf->resync_lock, flags);
734 spin_unlock_irqrestore(&conf->resync_lock, flags);
735 wake_up(&conf->wait_barrier);
738 static void wait_barrier(conf_t *conf)
740 spin_lock_irq(&conf->resync_lock);
743 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
749 spin_unlock_irq(&conf->resync_lock);
752 static void allow_barrier(conf_t *conf)
755 spin_lock_irqsave(&conf->resync_lock, flags);
757 spin_unlock_irqrestore(&conf->resync_lock, flags);
758 wake_up(&conf->wait_barrier);
761 static void freeze_array(conf_t *conf)
763 /* stop syncio and normal IO and wait for everything to
765 * We increment barrier and nr_waiting, and then
766 * wait until nr_pending match nr_queued+1
767 * This is called in the context of one normal IO request
768 * that has failed. Thus any sync request that might be pending
769 * will be blocked by nr_pending, and we need to wait for
770 * pending IO requests to complete or be queued for re-try.
771 * Thus the number queued (nr_queued) plus this request (1)
772 * must match the number of pending IOs (nr_pending) before
775 spin_lock_irq(&conf->resync_lock);
778 wait_event_lock_irq(conf->wait_barrier,
779 conf->nr_pending == conf->nr_queued+1,
781 flush_pending_writes(conf));
783 spin_unlock_irq(&conf->resync_lock);
786 static void unfreeze_array(conf_t *conf)
788 /* reverse the effect of the freeze */
789 spin_lock_irq(&conf->resync_lock);
792 wake_up(&conf->wait_barrier);
793 spin_unlock_irq(&conf->resync_lock);
796 static int make_request(mddev_t *mddev, struct bio * bio)
798 conf_t *conf = mddev->private;
799 mirror_info_t *mirror;
801 struct bio *read_bio;
803 int chunk_sects = conf->chunk_mask + 1;
804 const int rw = bio_data_dir(bio);
805 const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
806 const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
808 mdk_rdev_t *blocked_rdev;
811 if (unlikely(bio->bi_rw & REQ_FLUSH)) {
812 md_flush_request(mddev, bio);
816 /* If this request crosses a chunk boundary, we need to
817 * split it. This will only happen for 1 PAGE (or less) requests.
819 if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9)
821 conf->near_copies < conf->raid_disks)) {
823 /* Sanity check -- queue functions should prevent this happening */
824 if (bio->bi_vcnt != 1 ||
827 /* This is a one page bio that upper layers
828 * refuse to split for us, so we need to split it.
831 chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
833 /* Each of these 'make_request' calls will call 'wait_barrier'.
834 * If the first succeeds but the second blocks due to the resync
835 * thread raising the barrier, we will deadlock because the
836 * IO to the underlying device will be queued in generic_make_request
837 * and will never complete, so will never reduce nr_pending.
838 * So increment nr_waiting here so no new raise_barriers will
839 * succeed, and so the second wait_barrier cannot block.
841 spin_lock_irq(&conf->resync_lock);
843 spin_unlock_irq(&conf->resync_lock);
845 if (make_request(mddev, &bp->bio1))
846 generic_make_request(&bp->bio1);
847 if (make_request(mddev, &bp->bio2))
848 generic_make_request(&bp->bio2);
850 spin_lock_irq(&conf->resync_lock);
852 wake_up(&conf->wait_barrier);
853 spin_unlock_irq(&conf->resync_lock);
855 bio_pair_release(bp);
858 printk("md/raid10:%s: make_request bug: can't convert block across chunks"
859 " or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2,
860 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
866 md_write_start(mddev, bio);
869 * Register the new request and wait if the reconstruction
870 * thread has put up a bar for new requests.
871 * Continue immediately if no resync is active currently.
875 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
877 r10_bio->master_bio = bio;
878 r10_bio->sectors = bio->bi_size >> 9;
880 r10_bio->mddev = mddev;
881 r10_bio->sector = bio->bi_sector;
884 /* We might need to issue multiple reads to different
885 * devices if there are bad blocks around, so we keep
886 * track of the number of reads in bio->bi_phys_segments.
887 * If this is 0, there is only one r10_bio and no locking
888 * will be needed when the request completes. If it is
889 * non-zero, then it is the number of not-completed requests.
891 bio->bi_phys_segments = 0;
892 clear_bit(BIO_SEG_VALID, &bio->bi_flags);
896 * read balancing logic:
903 disk = read_balance(conf, r10_bio, &max_sectors);
904 slot = r10_bio->read_slot;
906 raid_end_bio_io(r10_bio);
909 mirror = conf->mirrors + disk;
911 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
912 md_trim_bio(read_bio, r10_bio->sector - bio->bi_sector,
915 r10_bio->devs[slot].bio = read_bio;
917 read_bio->bi_sector = r10_bio->devs[slot].addr +
918 mirror->rdev->data_offset;
919 read_bio->bi_bdev = mirror->rdev->bdev;
920 read_bio->bi_end_io = raid10_end_read_request;
921 read_bio->bi_rw = READ | do_sync;
922 read_bio->bi_private = r10_bio;
924 if (max_sectors < r10_bio->sectors) {
925 /* Could not read all from this device, so we will
926 * need another r10_bio.
930 sectors_handled = (r10_bio->sectors + max_sectors
932 r10_bio->sectors = max_sectors;
933 spin_lock_irq(&conf->device_lock);
934 if (bio->bi_phys_segments == 0)
935 bio->bi_phys_segments = 2;
937 bio->bi_phys_segments++;
938 spin_unlock(&conf->device_lock);
939 /* Cannot call generic_make_request directly
940 * as that will be queued in __generic_make_request
941 * and subsequent mempool_alloc might block
942 * waiting for it. so hand bio over to raid10d.
944 reschedule_retry(r10_bio);
946 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
948 r10_bio->master_bio = bio;
949 r10_bio->sectors = ((bio->bi_size >> 9)
952 r10_bio->mddev = mddev;
953 r10_bio->sector = bio->bi_sector + sectors_handled;
956 generic_make_request(read_bio);
963 /* first select target devices under rcu_lock and
964 * inc refcount on their rdev. Record them by setting
967 plugged = mddev_check_plugged(mddev);
969 raid10_find_phys(conf, r10_bio);
973 for (i = 0; i < conf->copies; i++) {
974 int d = r10_bio->devs[i].devnum;
975 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
976 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
977 atomic_inc(&rdev->nr_pending);
981 if (rdev && !test_bit(Faulty, &rdev->flags)) {
982 atomic_inc(&rdev->nr_pending);
983 r10_bio->devs[i].bio = bio;
985 r10_bio->devs[i].bio = NULL;
986 set_bit(R10BIO_Degraded, &r10_bio->state);
991 if (unlikely(blocked_rdev)) {
992 /* Have to wait for this device to get unblocked, then retry */
996 for (j = 0; j < i; j++)
997 if (r10_bio->devs[j].bio) {
998 d = r10_bio->devs[j].devnum;
999 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1001 allow_barrier(conf);
1002 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1007 atomic_set(&r10_bio->remaining, 1);
1008 bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0);
1010 for (i = 0; i < conf->copies; i++) {
1012 int d = r10_bio->devs[i].devnum;
1013 if (!r10_bio->devs[i].bio)
1016 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1017 r10_bio->devs[i].bio = mbio;
1019 mbio->bi_sector = r10_bio->devs[i].addr+
1020 conf->mirrors[d].rdev->data_offset;
1021 mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
1022 mbio->bi_end_io = raid10_end_write_request;
1023 mbio->bi_rw = WRITE | do_sync | do_fua;
1024 mbio->bi_private = r10_bio;
1026 atomic_inc(&r10_bio->remaining);
1027 spin_lock_irqsave(&conf->device_lock, flags);
1028 bio_list_add(&conf->pending_bio_list, mbio);
1029 spin_unlock_irqrestore(&conf->device_lock, flags);
1032 if (atomic_dec_and_test(&r10_bio->remaining)) {
1033 /* This matches the end of raid10_end_write_request() */
1034 bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
1036 !test_bit(R10BIO_Degraded, &r10_bio->state),
1038 md_write_end(mddev);
1039 raid_end_bio_io(r10_bio);
1042 /* In case raid10d snuck in to freeze_array */
1043 wake_up(&conf->wait_barrier);
1045 if (do_sync || !mddev->bitmap || !plugged)
1046 md_wakeup_thread(mddev->thread);
1050 static void status(struct seq_file *seq, mddev_t *mddev)
1052 conf_t *conf = mddev->private;
1055 if (conf->near_copies < conf->raid_disks)
1056 seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1057 if (conf->near_copies > 1)
1058 seq_printf(seq, " %d near-copies", conf->near_copies);
1059 if (conf->far_copies > 1) {
1060 if (conf->far_offset)
1061 seq_printf(seq, " %d offset-copies", conf->far_copies);
1063 seq_printf(seq, " %d far-copies", conf->far_copies);
1065 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1066 conf->raid_disks - mddev->degraded);
1067 for (i = 0; i < conf->raid_disks; i++)
1068 seq_printf(seq, "%s",
1069 conf->mirrors[i].rdev &&
1070 test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
1071 seq_printf(seq, "]");
1074 /* check if there are enough drives for
1075 * every block to appear on atleast one.
1076 * Don't consider the device numbered 'ignore'
1077 * as we might be about to remove it.
1079 static int enough(conf_t *conf, int ignore)
1084 int n = conf->copies;
1087 if (conf->mirrors[first].rdev &&
1090 first = (first+1) % conf->raid_disks;
1094 } while (first != 0);
1098 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1100 char b[BDEVNAME_SIZE];
1101 conf_t *conf = mddev->private;
1104 * If it is not operational, then we have already marked it as dead
1105 * else if it is the last working disks, ignore the error, let the
1106 * next level up know.
1107 * else mark the drive as failed
1109 if (test_bit(In_sync, &rdev->flags)
1110 && !enough(conf, rdev->raid_disk))
1112 * Don't fail the drive, just return an IO error.
1115 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1116 unsigned long flags;
1117 spin_lock_irqsave(&conf->device_lock, flags);
1119 spin_unlock_irqrestore(&conf->device_lock, flags);
1121 * if recovery is running, make sure it aborts.
1123 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1125 set_bit(Blocked, &rdev->flags);
1126 set_bit(Faulty, &rdev->flags);
1127 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1129 "md/raid10:%s: Disk failure on %s, disabling device.\n"
1130 "md/raid10:%s: Operation continuing on %d devices.\n",
1131 mdname(mddev), bdevname(rdev->bdev, b),
1132 mdname(mddev), conf->raid_disks - mddev->degraded);
1135 static void print_conf(conf_t *conf)
1140 printk(KERN_DEBUG "RAID10 conf printout:\n");
1142 printk(KERN_DEBUG "(!conf)\n");
1145 printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1148 for (i = 0; i < conf->raid_disks; i++) {
1149 char b[BDEVNAME_SIZE];
1150 tmp = conf->mirrors + i;
1152 printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1153 i, !test_bit(In_sync, &tmp->rdev->flags),
1154 !test_bit(Faulty, &tmp->rdev->flags),
1155 bdevname(tmp->rdev->bdev,b));
1159 static void close_sync(conf_t *conf)
1162 allow_barrier(conf);
1164 mempool_destroy(conf->r10buf_pool);
1165 conf->r10buf_pool = NULL;
1168 static int raid10_spare_active(mddev_t *mddev)
1171 conf_t *conf = mddev->private;
1174 unsigned long flags;
1177 * Find all non-in_sync disks within the RAID10 configuration
1178 * and mark them in_sync
1180 for (i = 0; i < conf->raid_disks; i++) {
1181 tmp = conf->mirrors + i;
1183 && !test_bit(Faulty, &tmp->rdev->flags)
1184 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1186 sysfs_notify_dirent(tmp->rdev->sysfs_state);
1189 spin_lock_irqsave(&conf->device_lock, flags);
1190 mddev->degraded -= count;
1191 spin_unlock_irqrestore(&conf->device_lock, flags);
1198 static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1200 conf_t *conf = mddev->private;
1204 int last = conf->raid_disks - 1;
1206 if (rdev->badblocks.count)
1209 if (mddev->recovery_cp < MaxSector)
1210 /* only hot-add to in-sync arrays, as recovery is
1211 * very different from resync
1214 if (!enough(conf, -1))
1217 if (rdev->raid_disk >= 0)
1218 first = last = rdev->raid_disk;
1220 if (rdev->saved_raid_disk >= first &&
1221 conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1222 mirror = rdev->saved_raid_disk;
1225 for ( ; mirror <= last ; mirror++) {
1226 mirror_info_t *p = &conf->mirrors[mirror];
1227 if (p->recovery_disabled == mddev->recovery_disabled)
1232 disk_stack_limits(mddev->gendisk, rdev->bdev,
1233 rdev->data_offset << 9);
1234 /* as we don't honour merge_bvec_fn, we must
1235 * never risk violating it, so limit
1236 * ->max_segments to one lying with a single
1237 * page, as a one page request is never in
1240 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
1241 blk_queue_max_segments(mddev->queue, 1);
1242 blk_queue_segment_boundary(mddev->queue,
1243 PAGE_CACHE_SIZE - 1);
1246 p->head_position = 0;
1247 rdev->raid_disk = mirror;
1249 if (rdev->saved_raid_disk != mirror)
1251 rcu_assign_pointer(p->rdev, rdev);
1255 md_integrity_add_rdev(rdev, mddev);
1260 static int raid10_remove_disk(mddev_t *mddev, int number)
1262 conf_t *conf = mddev->private;
1265 mirror_info_t *p = conf->mirrors+ number;
1270 if (test_bit(In_sync, &rdev->flags) ||
1271 atomic_read(&rdev->nr_pending)) {
1275 /* Only remove faulty devices in recovery
1278 if (!test_bit(Faulty, &rdev->flags) &&
1279 mddev->recovery_disabled != p->recovery_disabled &&
1286 if (atomic_read(&rdev->nr_pending)) {
1287 /* lost the race, try later */
1292 err = md_integrity_register(mddev);
1301 static void end_sync_read(struct bio *bio, int error)
1303 r10bio_t *r10_bio = bio->bi_private;
1304 conf_t *conf = r10_bio->mddev->private;
1307 d = find_bio_disk(conf, r10_bio, bio);
1309 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1310 set_bit(R10BIO_Uptodate, &r10_bio->state);
1312 atomic_add(r10_bio->sectors,
1313 &conf->mirrors[d].rdev->corrected_errors);
1314 if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
1315 md_error(r10_bio->mddev,
1316 conf->mirrors[d].rdev);
1319 /* for reconstruct, we always reschedule after a read.
1320 * for resync, only after all reads
1322 rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1323 if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1324 atomic_dec_and_test(&r10_bio->remaining)) {
1325 /* we have read all the blocks,
1326 * do the comparison in process context in raid10d
1328 reschedule_retry(r10_bio);
1332 static void end_sync_write(struct bio *bio, int error)
1334 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1335 r10bio_t *r10_bio = bio->bi_private;
1336 mddev_t *mddev = r10_bio->mddev;
1337 conf_t *conf = mddev->private;
1340 d = find_bio_disk(conf, r10_bio, bio);
1343 md_error(mddev, conf->mirrors[d].rdev);
1345 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1346 while (atomic_dec_and_test(&r10_bio->remaining)) {
1347 if (r10_bio->master_bio == NULL) {
1348 /* the primary of several recovery bios */
1349 sector_t s = r10_bio->sectors;
1351 md_done_sync(mddev, s, 1);
1354 r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio;
1362 * Note: sync and recover and handled very differently for raid10
1363 * This code is for resync.
1364 * For resync, we read through virtual addresses and read all blocks.
1365 * If there is any error, we schedule a write. The lowest numbered
1366 * drive is authoritative.
1367 * However requests come for physical address, so we need to map.
1368 * For every physical address there are raid_disks/copies virtual addresses,
1369 * which is always are least one, but is not necessarly an integer.
1370 * This means that a physical address can span multiple chunks, so we may
1371 * have to submit multiple io requests for a single sync request.
1374 * We check if all blocks are in-sync and only write to blocks that
1377 static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio)
1379 conf_t *conf = mddev->private;
1381 struct bio *tbio, *fbio;
1383 atomic_set(&r10_bio->remaining, 1);
1385 /* find the first device with a block */
1386 for (i=0; i<conf->copies; i++)
1387 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
1390 if (i == conf->copies)
1394 fbio = r10_bio->devs[i].bio;
1396 /* now find blocks with errors */
1397 for (i=0 ; i < conf->copies ; i++) {
1399 int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
1401 tbio = r10_bio->devs[i].bio;
1403 if (tbio->bi_end_io != end_sync_read)
1407 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) {
1408 /* We know that the bi_io_vec layout is the same for
1409 * both 'first' and 'i', so we just compare them.
1410 * All vec entries are PAGE_SIZE;
1412 for (j = 0; j < vcnt; j++)
1413 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
1414 page_address(tbio->bi_io_vec[j].bv_page),
1419 mddev->resync_mismatches += r10_bio->sectors;
1421 if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
1422 /* Don't fix anything. */
1424 /* Ok, we need to write this bio
1425 * First we need to fixup bv_offset, bv_len and
1426 * bi_vecs, as the read request might have corrupted these
1428 tbio->bi_vcnt = vcnt;
1429 tbio->bi_size = r10_bio->sectors << 9;
1431 tbio->bi_phys_segments = 0;
1432 tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1433 tbio->bi_flags |= 1 << BIO_UPTODATE;
1434 tbio->bi_next = NULL;
1435 tbio->bi_rw = WRITE;
1436 tbio->bi_private = r10_bio;
1437 tbio->bi_sector = r10_bio->devs[i].addr;
1439 for (j=0; j < vcnt ; j++) {
1440 tbio->bi_io_vec[j].bv_offset = 0;
1441 tbio->bi_io_vec[j].bv_len = PAGE_SIZE;
1443 memcpy(page_address(tbio->bi_io_vec[j].bv_page),
1444 page_address(fbio->bi_io_vec[j].bv_page),
1447 tbio->bi_end_io = end_sync_write;
1449 d = r10_bio->devs[i].devnum;
1450 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1451 atomic_inc(&r10_bio->remaining);
1452 md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
1454 tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
1455 tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
1456 generic_make_request(tbio);
1460 if (atomic_dec_and_test(&r10_bio->remaining)) {
1461 md_done_sync(mddev, r10_bio->sectors, 1);
1467 * Now for the recovery code.
1468 * Recovery happens across physical sectors.
1469 * We recover all non-is_sync drives by finding the virtual address of
1470 * each, and then choose a working drive that also has that virt address.
1471 * There is a separate r10_bio for each non-in_sync drive.
1472 * Only the first two slots are in use. The first for reading,
1473 * The second for writing.
1477 static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
1479 conf_t *conf = mddev->private;
1484 * share the pages with the first bio
1485 * and submit the write request
1487 wbio = r10_bio->devs[1].bio;
1488 d = r10_bio->devs[1].devnum;
1490 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1491 md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
1492 if (test_bit(R10BIO_Uptodate, &r10_bio->state))
1493 generic_make_request(wbio);
1496 "md/raid10:%s: recovery aborted due to read error\n",
1498 conf->mirrors[d].recovery_disabled = mddev->recovery_disabled;
1499 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1506 * Used by fix_read_error() to decay the per rdev read_errors.
1507 * We halve the read error count for every hour that has elapsed
1508 * since the last recorded read error.
1511 static void check_decay_read_errors(mddev_t *mddev, mdk_rdev_t *rdev)
1513 struct timespec cur_time_mon;
1514 unsigned long hours_since_last;
1515 unsigned int read_errors = atomic_read(&rdev->read_errors);
1517 ktime_get_ts(&cur_time_mon);
1519 if (rdev->last_read_error.tv_sec == 0 &&
1520 rdev->last_read_error.tv_nsec == 0) {
1521 /* first time we've seen a read error */
1522 rdev->last_read_error = cur_time_mon;
1526 hours_since_last = (cur_time_mon.tv_sec -
1527 rdev->last_read_error.tv_sec) / 3600;
1529 rdev->last_read_error = cur_time_mon;
1532 * if hours_since_last is > the number of bits in read_errors
1533 * just set read errors to 0. We do this to avoid
1534 * overflowing the shift of read_errors by hours_since_last.
1536 if (hours_since_last >= 8 * sizeof(read_errors))
1537 atomic_set(&rdev->read_errors, 0);
1539 atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
1543 * This is a kernel thread which:
1545 * 1. Retries failed read operations on working mirrors.
1546 * 2. Updates the raid superblock when problems encounter.
1547 * 3. Performs writes following reads for array synchronising.
1550 static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
1552 int sect = 0; /* Offset from r10_bio->sector */
1553 int sectors = r10_bio->sectors;
1555 int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
1556 int d = r10_bio->devs[r10_bio->read_slot].devnum;
1558 /* still own a reference to this rdev, so it cannot
1559 * have been cleared recently.
1561 rdev = conf->mirrors[d].rdev;
1563 if (test_bit(Faulty, &rdev->flags))
1564 /* drive has already been failed, just ignore any
1565 more fix_read_error() attempts */
1568 check_decay_read_errors(mddev, rdev);
1569 atomic_inc(&rdev->read_errors);
1570 if (atomic_read(&rdev->read_errors) > max_read_errors) {
1571 char b[BDEVNAME_SIZE];
1572 bdevname(rdev->bdev, b);
1575 "md/raid10:%s: %s: Raid device exceeded "
1576 "read_error threshold [cur %d:max %d]\n",
1578 atomic_read(&rdev->read_errors), max_read_errors);
1580 "md/raid10:%s: %s: Failing raid device\n",
1582 md_error(mddev, conf->mirrors[d].rdev);
1588 int sl = r10_bio->read_slot;
1592 if (s > (PAGE_SIZE>>9))
1597 d = r10_bio->devs[sl].devnum;
1598 rdev = rcu_dereference(conf->mirrors[d].rdev);
1600 test_bit(In_sync, &rdev->flags)) {
1601 atomic_inc(&rdev->nr_pending);
1603 success = sync_page_io(rdev,
1604 r10_bio->devs[sl].addr +
1607 conf->tmppage, READ, false);
1608 rdev_dec_pending(rdev, mddev);
1614 if (sl == conf->copies)
1616 } while (!success && sl != r10_bio->read_slot);
1620 /* Cannot read from anywhere -- bye bye array */
1621 int dn = r10_bio->devs[r10_bio->read_slot].devnum;
1622 md_error(mddev, conf->mirrors[dn].rdev);
1627 /* write it back and re-read */
1629 while (sl != r10_bio->read_slot) {
1630 char b[BDEVNAME_SIZE];
1635 d = r10_bio->devs[sl].devnum;
1636 rdev = rcu_dereference(conf->mirrors[d].rdev);
1638 !test_bit(In_sync, &rdev->flags))
1641 atomic_inc(&rdev->nr_pending);
1643 if (sync_page_io(rdev,
1644 r10_bio->devs[sl].addr +
1646 s<<9, conf->tmppage, WRITE, false)
1648 /* Well, this device is dead */
1650 "md/raid10:%s: read correction "
1652 " (%d sectors at %llu on %s)\n",
1654 (unsigned long long)(
1655 sect + rdev->data_offset),
1656 bdevname(rdev->bdev, b));
1657 printk(KERN_NOTICE "md/raid10:%s: %s: failing "
1660 bdevname(rdev->bdev, b));
1661 md_error(mddev, rdev);
1663 rdev_dec_pending(rdev, mddev);
1667 while (sl != r10_bio->read_slot) {
1668 char b[BDEVNAME_SIZE];
1673 d = r10_bio->devs[sl].devnum;
1674 rdev = rcu_dereference(conf->mirrors[d].rdev);
1676 !test_bit(In_sync, &rdev->flags))
1679 atomic_inc(&rdev->nr_pending);
1681 if (sync_page_io(rdev,
1682 r10_bio->devs[sl].addr +
1684 s<<9, conf->tmppage,
1685 READ, false) == 0) {
1686 /* Well, this device is dead */
1688 "md/raid10:%s: unable to read back "
1690 " (%d sectors at %llu on %s)\n",
1692 (unsigned long long)(
1693 sect + rdev->data_offset),
1694 bdevname(rdev->bdev, b));
1695 printk(KERN_NOTICE "md/raid10:%s: %s: failing "
1698 bdevname(rdev->bdev, b));
1700 md_error(mddev, rdev);
1703 "md/raid10:%s: read error corrected"
1704 " (%d sectors at %llu on %s)\n",
1706 (unsigned long long)(
1707 sect + rdev->data_offset),
1708 bdevname(rdev->bdev, b));
1709 atomic_add(s, &rdev->corrected_errors);
1712 rdev_dec_pending(rdev, mddev);
1722 static void handle_read_error(mddev_t *mddev, r10bio_t *r10_bio)
1724 int slot = r10_bio->read_slot;
1725 int mirror = r10_bio->devs[slot].devnum;
1727 conf_t *conf = mddev->private;
1729 char b[BDEVNAME_SIZE];
1730 unsigned long do_sync;
1733 /* we got a read error. Maybe the drive is bad. Maybe just
1734 * the block and we can fix it.
1735 * We freeze all other IO, and try reading the block from
1736 * other devices. When we find one, we re-write
1737 * and check it that fixes the read error.
1738 * This is all done synchronously while the array is
1741 if (mddev->ro == 0) {
1743 fix_read_error(conf, mddev, r10_bio);
1744 unfreeze_array(conf);
1746 rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
1748 bio = r10_bio->devs[slot].bio;
1749 bdevname(bio->bi_bdev, b);
1750 r10_bio->devs[slot].bio =
1751 mddev->ro ? IO_BLOCKED : NULL;
1753 mirror = read_balance(conf, r10_bio, &max_sectors);
1755 printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O"
1756 " read error for block %llu\n",
1758 (unsigned long long)r10_bio->sector);
1759 raid_end_bio_io(r10_bio);
1764 do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC);
1767 slot = r10_bio->read_slot;
1768 rdev = conf->mirrors[mirror].rdev;
1771 "md/raid10:%s: %s: redirecting"
1772 "sector %llu to another mirror\n",
1774 bdevname(rdev->bdev, b),
1775 (unsigned long long)r10_bio->sector);
1776 bio = bio_clone_mddev(r10_bio->master_bio,
1779 r10_bio->sector - bio->bi_sector,
1781 r10_bio->devs[slot].bio = bio;
1782 bio->bi_sector = r10_bio->devs[slot].addr
1783 + rdev->data_offset;
1784 bio->bi_bdev = rdev->bdev;
1785 bio->bi_rw = READ | do_sync;
1786 bio->bi_private = r10_bio;
1787 bio->bi_end_io = raid10_end_read_request;
1788 if (max_sectors < r10_bio->sectors) {
1789 /* Drat - have to split this up more */
1790 struct bio *mbio = r10_bio->master_bio;
1791 int sectors_handled =
1792 r10_bio->sector + max_sectors
1794 r10_bio->sectors = max_sectors;
1795 spin_lock_irq(&conf->device_lock);
1796 if (mbio->bi_phys_segments == 0)
1797 mbio->bi_phys_segments = 2;
1799 mbio->bi_phys_segments++;
1800 spin_unlock_irq(&conf->device_lock);
1801 generic_make_request(bio);
1804 r10_bio = mempool_alloc(conf->r10bio_pool,
1806 r10_bio->master_bio = mbio;
1807 r10_bio->sectors = (mbio->bi_size >> 9)
1810 set_bit(R10BIO_ReadError,
1812 r10_bio->mddev = mddev;
1813 r10_bio->sector = mbio->bi_sector
1818 generic_make_request(bio);
1821 static void raid10d(mddev_t *mddev)
1824 unsigned long flags;
1825 conf_t *conf = mddev->private;
1826 struct list_head *head = &conf->retry_list;
1827 struct blk_plug plug;
1829 md_check_recovery(mddev);
1831 blk_start_plug(&plug);
1834 flush_pending_writes(conf);
1836 spin_lock_irqsave(&conf->device_lock, flags);
1837 if (list_empty(head)) {
1838 spin_unlock_irqrestore(&conf->device_lock, flags);
1841 r10_bio = list_entry(head->prev, r10bio_t, retry_list);
1842 list_del(head->prev);
1844 spin_unlock_irqrestore(&conf->device_lock, flags);
1846 mddev = r10_bio->mddev;
1847 conf = mddev->private;
1848 if (test_bit(R10BIO_IsSync, &r10_bio->state))
1849 sync_request_write(mddev, r10_bio);
1850 else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
1851 recovery_request_write(mddev, r10_bio);
1852 else if (test_bit(R10BIO_ReadError, &r10_bio->state))
1853 handle_read_error(mddev, r10_bio);
1855 /* just a partial read to be scheduled from a
1858 int slot = r10_bio->read_slot;
1859 generic_make_request(r10_bio->devs[slot].bio);
1863 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
1864 md_check_recovery(mddev);
1866 blk_finish_plug(&plug);
1870 static int init_resync(conf_t *conf)
1874 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1875 BUG_ON(conf->r10buf_pool);
1876 conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
1877 if (!conf->r10buf_pool)
1879 conf->next_resync = 0;
1884 * perform a "sync" on one "block"
1886 * We need to make sure that no normal I/O request - particularly write
1887 * requests - conflict with active sync requests.
1889 * This is achieved by tracking pending requests and a 'barrier' concept
1890 * that can be installed to exclude normal IO requests.
1892 * Resync and recovery are handled very differently.
1893 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
1895 * For resync, we iterate over virtual addresses, read all copies,
1896 * and update if there are differences. If only one copy is live,
1898 * For recovery, we iterate over physical addresses, read a good
1899 * value for each non-in_sync drive, and over-write.
1901 * So, for recovery we may have several outstanding complex requests for a
1902 * given address, one for each out-of-sync device. We model this by allocating
1903 * a number of r10_bio structures, one for each out-of-sync device.
1904 * As we setup these structures, we collect all bio's together into a list
1905 * which we then process collectively to add pages, and then process again
1906 * to pass to generic_make_request.
1908 * The r10_bio structures are linked using a borrowed master_bio pointer.
1909 * This link is counted in ->remaining. When the r10_bio that points to NULL
1910 * has its remaining count decremented to 0, the whole complex operation
1915 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr,
1916 int *skipped, int go_faster)
1918 conf_t *conf = mddev->private;
1920 struct bio *biolist = NULL, *bio;
1921 sector_t max_sector, nr_sectors;
1924 sector_t sync_blocks;
1926 sector_t sectors_skipped = 0;
1927 int chunks_skipped = 0;
1929 if (!conf->r10buf_pool)
1930 if (init_resync(conf))
1934 max_sector = mddev->dev_sectors;
1935 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
1936 max_sector = mddev->resync_max_sectors;
1937 if (sector_nr >= max_sector) {
1938 /* If we aborted, we need to abort the
1939 * sync on the 'current' bitmap chucks (there can
1940 * be several when recovering multiple devices).
1941 * as we may have started syncing it but not finished.
1942 * We can find the current address in
1943 * mddev->curr_resync, but for recovery,
1944 * we need to convert that to several
1945 * virtual addresses.
1947 if (mddev->curr_resync < max_sector) { /* aborted */
1948 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
1949 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1951 else for (i=0; i<conf->raid_disks; i++) {
1953 raid10_find_virt(conf, mddev->curr_resync, i);
1954 bitmap_end_sync(mddev->bitmap, sect,
1957 } else /* completed sync */
1960 bitmap_close_sync(mddev->bitmap);
1963 return sectors_skipped;
1965 if (chunks_skipped >= conf->raid_disks) {
1966 /* if there has been nothing to do on any drive,
1967 * then there is nothing to do at all..
1970 return (max_sector - sector_nr) + sectors_skipped;
1973 if (max_sector > mddev->resync_max)
1974 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1976 /* make sure whole request will fit in a chunk - if chunks
1979 if (conf->near_copies < conf->raid_disks &&
1980 max_sector > (sector_nr | conf->chunk_mask))
1981 max_sector = (sector_nr | conf->chunk_mask) + 1;
1983 * If there is non-resync activity waiting for us then
1984 * put in a delay to throttle resync.
1986 if (!go_faster && conf->nr_waiting)
1987 msleep_interruptible(1000);
1989 /* Again, very different code for resync and recovery.
1990 * Both must result in an r10bio with a list of bios that
1991 * have bi_end_io, bi_sector, bi_bdev set,
1992 * and bi_private set to the r10bio.
1993 * For recovery, we may actually create several r10bios
1994 * with 2 bios in each, that correspond to the bios in the main one.
1995 * In this case, the subordinate r10bios link back through a
1996 * borrowed master_bio pointer, and the counter in the master
1997 * includes a ref from each subordinate.
1999 /* First, we decide what to do and set ->bi_end_io
2000 * To end_sync_read if we want to read, and
2001 * end_sync_write if we will want to write.
2004 max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
2005 if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2006 /* recovery... the complicated one */
2010 for (i=0 ; i<conf->raid_disks; i++) {
2016 if (conf->mirrors[i].rdev == NULL ||
2017 test_bit(In_sync, &conf->mirrors[i].rdev->flags))
2021 /* want to reconstruct this device */
2023 sect = raid10_find_virt(conf, sector_nr, i);
2024 /* Unless we are doing a full sync, we only need
2025 * to recover the block if it is set in the bitmap
2027 must_sync = bitmap_start_sync(mddev->bitmap, sect,
2029 if (sync_blocks < max_sync)
2030 max_sync = sync_blocks;
2033 /* yep, skip the sync_blocks here, but don't assume
2034 * that there will never be anything to do here
2036 chunks_skipped = -1;
2040 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
2041 raise_barrier(conf, rb2 != NULL);
2042 atomic_set(&r10_bio->remaining, 0);
2044 r10_bio->master_bio = (struct bio*)rb2;
2046 atomic_inc(&rb2->remaining);
2047 r10_bio->mddev = mddev;
2048 set_bit(R10BIO_IsRecover, &r10_bio->state);
2049 r10_bio->sector = sect;
2051 raid10_find_phys(conf, r10_bio);
2053 /* Need to check if the array will still be
2056 for (j=0; j<conf->raid_disks; j++)
2057 if (conf->mirrors[j].rdev == NULL ||
2058 test_bit(Faulty, &conf->mirrors[j].rdev->flags)) {
2063 must_sync = bitmap_start_sync(mddev->bitmap, sect,
2064 &sync_blocks, still_degraded);
2066 for (j=0; j<conf->copies;j++) {
2067 int d = r10_bio->devs[j].devnum;
2068 if (!conf->mirrors[d].rdev ||
2069 !test_bit(In_sync, &conf->mirrors[d].rdev->flags))
2071 /* This is where we read from */
2072 bio = r10_bio->devs[0].bio;
2073 bio->bi_next = biolist;
2075 bio->bi_private = r10_bio;
2076 bio->bi_end_io = end_sync_read;
2078 bio->bi_sector = r10_bio->devs[j].addr +
2079 conf->mirrors[d].rdev->data_offset;
2080 bio->bi_bdev = conf->mirrors[d].rdev->bdev;
2081 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2082 atomic_inc(&r10_bio->remaining);
2083 /* and we write to 'i' */
2085 for (k=0; k<conf->copies; k++)
2086 if (r10_bio->devs[k].devnum == i)
2088 BUG_ON(k == conf->copies);
2089 bio = r10_bio->devs[1].bio;
2090 bio->bi_next = biolist;
2092 bio->bi_private = r10_bio;
2093 bio->bi_end_io = end_sync_write;
2095 bio->bi_sector = r10_bio->devs[k].addr +
2096 conf->mirrors[i].rdev->data_offset;
2097 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
2099 r10_bio->devs[0].devnum = d;
2100 r10_bio->devs[1].devnum = i;
2104 if (j == conf->copies) {
2105 /* Cannot recover, so abort the recovery */
2108 atomic_dec(&rb2->remaining);
2110 if (!test_and_set_bit(MD_RECOVERY_INTR,
2112 printk(KERN_INFO "md/raid10:%s: insufficient "
2113 "working devices for recovery.\n",
2118 if (biolist == NULL) {
2120 r10bio_t *rb2 = r10_bio;
2121 r10_bio = (r10bio_t*) rb2->master_bio;
2122 rb2->master_bio = NULL;
2128 /* resync. Schedule a read for every block at this virt offset */
2131 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2133 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2134 &sync_blocks, mddev->degraded) &&
2135 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
2136 &mddev->recovery)) {
2137 /* We can skip this block */
2139 return sync_blocks + sectors_skipped;
2141 if (sync_blocks < max_sync)
2142 max_sync = sync_blocks;
2143 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
2145 r10_bio->mddev = mddev;
2146 atomic_set(&r10_bio->remaining, 0);
2147 raise_barrier(conf, 0);
2148 conf->next_resync = sector_nr;
2150 r10_bio->master_bio = NULL;
2151 r10_bio->sector = sector_nr;
2152 set_bit(R10BIO_IsSync, &r10_bio->state);
2153 raid10_find_phys(conf, r10_bio);
2154 r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1;
2156 for (i=0; i<conf->copies; i++) {
2157 int d = r10_bio->devs[i].devnum;
2158 bio = r10_bio->devs[i].bio;
2159 bio->bi_end_io = NULL;
2160 clear_bit(BIO_UPTODATE, &bio->bi_flags);
2161 if (conf->mirrors[d].rdev == NULL ||
2162 test_bit(Faulty, &conf->mirrors[d].rdev->flags))
2164 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2165 atomic_inc(&r10_bio->remaining);
2166 bio->bi_next = biolist;
2168 bio->bi_private = r10_bio;
2169 bio->bi_end_io = end_sync_read;
2171 bio->bi_sector = r10_bio->devs[i].addr +
2172 conf->mirrors[d].rdev->data_offset;
2173 bio->bi_bdev = conf->mirrors[d].rdev->bdev;
2178 for (i=0; i<conf->copies; i++) {
2179 int d = r10_bio->devs[i].devnum;
2180 if (r10_bio->devs[i].bio->bi_end_io)
2181 rdev_dec_pending(conf->mirrors[d].rdev,
2190 for (bio = biolist; bio ; bio=bio->bi_next) {
2192 bio->bi_flags &= ~(BIO_POOL_MASK - 1);
2194 bio->bi_flags |= 1 << BIO_UPTODATE;
2197 bio->bi_phys_segments = 0;
2202 if (sector_nr + max_sync < max_sector)
2203 max_sector = sector_nr + max_sync;
2206 int len = PAGE_SIZE;
2207 if (sector_nr + (len>>9) > max_sector)
2208 len = (max_sector - sector_nr) << 9;
2211 for (bio= biolist ; bio ; bio=bio->bi_next) {
2213 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2214 if (bio_add_page(bio, page, len, 0))
2218 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2219 for (bio2 = biolist;
2220 bio2 && bio2 != bio;
2221 bio2 = bio2->bi_next) {
2222 /* remove last page from this bio */
2224 bio2->bi_size -= len;
2225 bio2->bi_flags &= ~(1<< BIO_SEG_VALID);
2229 nr_sectors += len>>9;
2230 sector_nr += len>>9;
2231 } while (biolist->bi_vcnt < RESYNC_PAGES);
2233 r10_bio->sectors = nr_sectors;
2237 biolist = biolist->bi_next;
2239 bio->bi_next = NULL;
2240 r10_bio = bio->bi_private;
2241 r10_bio->sectors = nr_sectors;
2243 if (bio->bi_end_io == end_sync_read) {
2244 md_sync_acct(bio->bi_bdev, nr_sectors);
2245 generic_make_request(bio);
2249 if (sectors_skipped)
2250 /* pretend they weren't skipped, it makes
2251 * no important difference in this case
2253 md_done_sync(mddev, sectors_skipped, 1);
2255 return sectors_skipped + nr_sectors;
2257 /* There is nowhere to write, so all non-sync
2258 * drives must be failed, so try the next chunk...
2260 if (sector_nr + max_sync < max_sector)
2261 max_sector = sector_nr + max_sync;
2263 sectors_skipped += (max_sector - sector_nr);
2265 sector_nr = max_sector;
2270 raid10_size(mddev_t *mddev, sector_t sectors, int raid_disks)
2273 conf_t *conf = mddev->private;
2276 raid_disks = conf->raid_disks;
2278 sectors = conf->dev_sectors;
2280 size = sectors >> conf->chunk_shift;
2281 sector_div(size, conf->far_copies);
2282 size = size * raid_disks;
2283 sector_div(size, conf->near_copies);
2285 return size << conf->chunk_shift;
2289 static conf_t *setup_conf(mddev_t *mddev)
2291 conf_t *conf = NULL;
2293 sector_t stride, size;
2296 if (mddev->new_chunk_sectors < (PAGE_SIZE >> 9) ||
2297 !is_power_of_2(mddev->new_chunk_sectors)) {
2298 printk(KERN_ERR "md/raid10:%s: chunk size must be "
2299 "at least PAGE_SIZE(%ld) and be a power of 2.\n",
2300 mdname(mddev), PAGE_SIZE);
2304 nc = mddev->new_layout & 255;
2305 fc = (mddev->new_layout >> 8) & 255;
2306 fo = mddev->new_layout & (1<<16);
2308 if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks ||
2309 (mddev->new_layout >> 17)) {
2310 printk(KERN_ERR "md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
2311 mdname(mddev), mddev->new_layout);
2316 conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
2320 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
2325 conf->tmppage = alloc_page(GFP_KERNEL);
2330 conf->raid_disks = mddev->raid_disks;
2331 conf->near_copies = nc;
2332 conf->far_copies = fc;
2333 conf->copies = nc*fc;
2334 conf->far_offset = fo;
2335 conf->chunk_mask = mddev->new_chunk_sectors - 1;
2336 conf->chunk_shift = ffz(~mddev->new_chunk_sectors);
2338 conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
2339 r10bio_pool_free, conf);
2340 if (!conf->r10bio_pool)
2343 size = mddev->dev_sectors >> conf->chunk_shift;
2344 sector_div(size, fc);
2345 size = size * conf->raid_disks;
2346 sector_div(size, nc);
2347 /* 'size' is now the number of chunks in the array */
2348 /* calculate "used chunks per device" in 'stride' */
2349 stride = size * conf->copies;
2351 /* We need to round up when dividing by raid_disks to
2352 * get the stride size.
2354 stride += conf->raid_disks - 1;
2355 sector_div(stride, conf->raid_disks);
2357 conf->dev_sectors = stride << conf->chunk_shift;
2362 sector_div(stride, fc);
2363 conf->stride = stride << conf->chunk_shift;
2366 spin_lock_init(&conf->device_lock);
2367 INIT_LIST_HEAD(&conf->retry_list);
2369 spin_lock_init(&conf->resync_lock);
2370 init_waitqueue_head(&conf->wait_barrier);
2372 conf->thread = md_register_thread(raid10d, mddev, NULL);
2376 conf->mddev = mddev;
2380 printk(KERN_ERR "md/raid10:%s: couldn't allocate memory.\n",
2383 if (conf->r10bio_pool)
2384 mempool_destroy(conf->r10bio_pool);
2385 kfree(conf->mirrors);
2386 safe_put_page(conf->tmppage);
2389 return ERR_PTR(err);
2392 static int run(mddev_t *mddev)
2395 int i, disk_idx, chunk_size;
2396 mirror_info_t *disk;
2401 * copy the already verified devices into our private RAID10
2402 * bookkeeping area. [whatever we allocate in run(),
2403 * should be freed in stop()]
2406 if (mddev->private == NULL) {
2407 conf = setup_conf(mddev);
2409 return PTR_ERR(conf);
2410 mddev->private = conf;
2412 conf = mddev->private;
2416 mddev->thread = conf->thread;
2417 conf->thread = NULL;
2419 chunk_size = mddev->chunk_sectors << 9;
2420 blk_queue_io_min(mddev->queue, chunk_size);
2421 if (conf->raid_disks % conf->near_copies)
2422 blk_queue_io_opt(mddev->queue, chunk_size * conf->raid_disks);
2424 blk_queue_io_opt(mddev->queue, chunk_size *
2425 (conf->raid_disks / conf->near_copies));
2427 list_for_each_entry(rdev, &mddev->disks, same_set) {
2429 if (rdev->badblocks.count) {
2430 printk(KERN_ERR "md/raid10: cannot handle bad blocks yet\n");
2433 disk_idx = rdev->raid_disk;
2434 if (disk_idx >= conf->raid_disks
2437 disk = conf->mirrors + disk_idx;
2440 disk_stack_limits(mddev->gendisk, rdev->bdev,
2441 rdev->data_offset << 9);
2442 /* as we don't honour merge_bvec_fn, we must never risk
2443 * violating it, so limit max_segments to 1 lying
2444 * within a single page.
2446 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
2447 blk_queue_max_segments(mddev->queue, 1);
2448 blk_queue_segment_boundary(mddev->queue,
2449 PAGE_CACHE_SIZE - 1);
2452 disk->head_position = 0;
2454 /* need to check that every block has at least one working mirror */
2455 if (!enough(conf, -1)) {
2456 printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n",
2461 mddev->degraded = 0;
2462 for (i = 0; i < conf->raid_disks; i++) {
2464 disk = conf->mirrors + i;
2467 !test_bit(In_sync, &disk->rdev->flags)) {
2468 disk->head_position = 0;
2475 if (mddev->recovery_cp != MaxSector)
2476 printk(KERN_NOTICE "md/raid10:%s: not clean"
2477 " -- starting background reconstruction\n",
2480 "md/raid10:%s: active with %d out of %d devices\n",
2481 mdname(mddev), conf->raid_disks - mddev->degraded,
2484 * Ok, everything is just fine now
2486 mddev->dev_sectors = conf->dev_sectors;
2487 size = raid10_size(mddev, 0, 0);
2488 md_set_array_sectors(mddev, size);
2489 mddev->resync_max_sectors = size;
2491 mddev->queue->backing_dev_info.congested_fn = raid10_congested;
2492 mddev->queue->backing_dev_info.congested_data = mddev;
2494 /* Calculate max read-ahead size.
2495 * We need to readahead at least twice a whole stripe....
2499 int stripe = conf->raid_disks *
2500 ((mddev->chunk_sectors << 9) / PAGE_SIZE);
2501 stripe /= conf->near_copies;
2502 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
2503 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
2506 if (conf->near_copies < conf->raid_disks)
2507 blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
2509 if (md_integrity_register(mddev))
2515 md_unregister_thread(mddev->thread);
2516 if (conf->r10bio_pool)
2517 mempool_destroy(conf->r10bio_pool);
2518 safe_put_page(conf->tmppage);
2519 kfree(conf->mirrors);
2521 mddev->private = NULL;
2526 static int stop(mddev_t *mddev)
2528 conf_t *conf = mddev->private;
2530 raise_barrier(conf, 0);
2531 lower_barrier(conf);
2533 md_unregister_thread(mddev->thread);
2534 mddev->thread = NULL;
2535 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2536 if (conf->r10bio_pool)
2537 mempool_destroy(conf->r10bio_pool);
2538 kfree(conf->mirrors);
2540 mddev->private = NULL;
2544 static void raid10_quiesce(mddev_t *mddev, int state)
2546 conf_t *conf = mddev->private;
2550 raise_barrier(conf, 0);
2553 lower_barrier(conf);
2558 static void *raid10_takeover_raid0(mddev_t *mddev)
2563 if (mddev->degraded > 0) {
2564 printk(KERN_ERR "md/raid10:%s: Error: degraded raid0!\n",
2566 return ERR_PTR(-EINVAL);
2569 /* Set new parameters */
2570 mddev->new_level = 10;
2571 /* new layout: far_copies = 1, near_copies = 2 */
2572 mddev->new_layout = (1<<8) + 2;
2573 mddev->new_chunk_sectors = mddev->chunk_sectors;
2574 mddev->delta_disks = mddev->raid_disks;
2575 mddev->raid_disks *= 2;
2576 /* make sure it will be not marked as dirty */
2577 mddev->recovery_cp = MaxSector;
2579 conf = setup_conf(mddev);
2580 if (!IS_ERR(conf)) {
2581 list_for_each_entry(rdev, &mddev->disks, same_set)
2582 if (rdev->raid_disk >= 0)
2583 rdev->new_raid_disk = rdev->raid_disk * 2;
2590 static void *raid10_takeover(mddev_t *mddev)
2592 struct raid0_private_data *raid0_priv;
2594 /* raid10 can take over:
2595 * raid0 - providing it has only two drives
2597 if (mddev->level == 0) {
2598 /* for raid0 takeover only one zone is supported */
2599 raid0_priv = mddev->private;
2600 if (raid0_priv->nr_strip_zones > 1) {
2601 printk(KERN_ERR "md/raid10:%s: cannot takeover raid 0"
2602 " with more than one zone.\n",
2604 return ERR_PTR(-EINVAL);
2606 return raid10_takeover_raid0(mddev);
2608 return ERR_PTR(-EINVAL);
2611 static struct mdk_personality raid10_personality =
2615 .owner = THIS_MODULE,
2616 .make_request = make_request,
2620 .error_handler = error,
2621 .hot_add_disk = raid10_add_disk,
2622 .hot_remove_disk= raid10_remove_disk,
2623 .spare_active = raid10_spare_active,
2624 .sync_request = sync_request,
2625 .quiesce = raid10_quiesce,
2626 .size = raid10_size,
2627 .takeover = raid10_takeover,
2630 static int __init raid_init(void)
2632 return register_md_personality(&raid10_personality);
2635 static void raid_exit(void)
2637 unregister_md_personality(&raid10_personality);
2640 module_init(raid_init);
2641 module_exit(raid_exit);
2642 MODULE_LICENSE("GPL");
2643 MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
2644 MODULE_ALIAS("md-personality-9"); /* RAID10 */
2645 MODULE_ALIAS("md-raid10");
2646 MODULE_ALIAS("md-level-10");