m32r: __xchg() should be always_inline
[linux-2.6.22.y-op.git] / drivers / md / raid10.c
blob82249a69014f0295055d10d750d297ac8e4291c6
1 /*
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 futher 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)
14 * any later version.
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 "dm-bio-list.h"
22 #include <linux/raid/raid10.h>
23 #include <linux/raid/bitmap.h>
26 * RAID10 provides a combination of RAID0 and RAID1 functionality.
27 * The layout of data is defined by
28 * chunk_size
29 * raid_disks
30 * near_copies (stored in low byte of layout)
31 * far_copies (stored in second byte of layout)
32 * far_offset (stored in bit 16 of layout )
34 * The data to be stored is divided into chunks using chunksize.
35 * Each device is divided into far_copies sections.
36 * In each section, chunks are laid out in a style similar to raid0, but
37 * near_copies copies of each chunk is stored (each on a different drive).
38 * The starting device for each section is offset near_copies from the starting
39 * device of the previous section.
40 * Thus they are (near_copies*far_copies) of each chunk, and each is on a different
41 * drive.
42 * near_copies and far_copies must be at least one, and their product is at most
43 * raid_disks.
45 * If far_offset is true, then the far_copies are handled a bit differently.
46 * The copies are still in different stripes, but instead of be very far apart
47 * on disk, there are adjacent stripes.
51 * Number of guaranteed r10bios in case of extreme VM load:
53 #define NR_RAID10_BIOS 256
55 static void unplug_slaves(mddev_t *mddev);
57 static void allow_barrier(conf_t *conf);
58 static void lower_barrier(conf_t *conf);
60 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
62 conf_t *conf = data;
63 r10bio_t *r10_bio;
64 int size = offsetof(struct r10bio_s, devs[conf->copies]);
66 /* allocate a r10bio with room for raid_disks entries in the bios array */
67 r10_bio = kzalloc(size, gfp_flags);
68 if (!r10_bio)
69 unplug_slaves(conf->mddev);
71 return r10_bio;
74 static void r10bio_pool_free(void *r10_bio, void *data)
76 kfree(r10_bio);
79 #define RESYNC_BLOCK_SIZE (64*1024)
80 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
81 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
82 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
83 #define RESYNC_WINDOW (2048*1024)
86 * When performing a resync, we need to read and compare, so
87 * we need as many pages are there are copies.
88 * When performing a recovery, we need 2 bios, one for read,
89 * one for write (we recover only one drive per r10buf)
92 static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
94 conf_t *conf = data;
95 struct page *page;
96 r10bio_t *r10_bio;
97 struct bio *bio;
98 int i, j;
99 int nalloc;
101 r10_bio = r10bio_pool_alloc(gfp_flags, conf);
102 if (!r10_bio) {
103 unplug_slaves(conf->mddev);
104 return NULL;
107 if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
108 nalloc = conf->copies; /* resync */
109 else
110 nalloc = 2; /* recovery */
113 * Allocate bios.
115 for (j = nalloc ; j-- ; ) {
116 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
117 if (!bio)
118 goto out_free_bio;
119 r10_bio->devs[j].bio = bio;
122 * Allocate RESYNC_PAGES data pages and attach them
123 * where needed.
125 for (j = 0 ; j < nalloc; j++) {
126 bio = r10_bio->devs[j].bio;
127 for (i = 0; i < RESYNC_PAGES; i++) {
128 page = alloc_page(gfp_flags);
129 if (unlikely(!page))
130 goto out_free_pages;
132 bio->bi_io_vec[i].bv_page = page;
136 return r10_bio;
138 out_free_pages:
139 for ( ; i > 0 ; i--)
140 safe_put_page(bio->bi_io_vec[i-1].bv_page);
141 while (j--)
142 for (i = 0; i < RESYNC_PAGES ; i++)
143 safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
144 j = -1;
145 out_free_bio:
146 while ( ++j < nalloc )
147 bio_put(r10_bio->devs[j].bio);
148 r10bio_pool_free(r10_bio, conf);
149 return NULL;
152 static void r10buf_pool_free(void *__r10_bio, void *data)
154 int i;
155 conf_t *conf = data;
156 r10bio_t *r10bio = __r10_bio;
157 int j;
159 for (j=0; j < conf->copies; j++) {
160 struct bio *bio = r10bio->devs[j].bio;
161 if (bio) {
162 for (i = 0; i < RESYNC_PAGES; i++) {
163 safe_put_page(bio->bi_io_vec[i].bv_page);
164 bio->bi_io_vec[i].bv_page = NULL;
166 bio_put(bio);
169 r10bio_pool_free(r10bio, conf);
172 static void put_all_bios(conf_t *conf, r10bio_t *r10_bio)
174 int i;
176 for (i = 0; i < conf->copies; i++) {
177 struct bio **bio = & r10_bio->devs[i].bio;
178 if (*bio && *bio != IO_BLOCKED)
179 bio_put(*bio);
180 *bio = NULL;
184 static void free_r10bio(r10bio_t *r10_bio)
186 conf_t *conf = mddev_to_conf(r10_bio->mddev);
189 * Wake up any possible resync thread that waits for the device
190 * to go idle.
192 allow_barrier(conf);
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 = mddev_to_conf(r10_bio->mddev);
202 mempool_free(r10_bio, conf->r10buf_pool);
204 lower_barrier(conf);
207 static void reschedule_retry(r10bio_t *r10_bio)
209 unsigned long flags;
210 mddev_t *mddev = r10_bio->mddev;
211 conf_t *conf = mddev_to_conf(mddev);
213 spin_lock_irqsave(&conf->device_lock, flags);
214 list_add(&r10_bio->retry_list, &conf->retry_list);
215 conf->nr_queued ++;
216 spin_unlock_irqrestore(&conf->device_lock, flags);
218 md_wakeup_thread(mddev->thread);
222 * raid_end_bio_io() is called when we have finished servicing a mirrored
223 * operation and are ready to return a success/failure code to the buffer
224 * cache layer.
226 static void raid_end_bio_io(r10bio_t *r10_bio)
228 struct bio *bio = r10_bio->master_bio;
230 bio_endio(bio, bio->bi_size,
231 test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO);
232 free_r10bio(r10_bio);
236 * Update disk head position estimator based on IRQ completion info.
238 static inline void update_head_pos(int slot, r10bio_t *r10_bio)
240 conf_t *conf = mddev_to_conf(r10_bio->mddev);
242 conf->mirrors[r10_bio->devs[slot].devnum].head_position =
243 r10_bio->devs[slot].addr + (r10_bio->sectors);
246 static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
248 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
249 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
250 int slot, dev;
251 conf_t *conf = mddev_to_conf(r10_bio->mddev);
253 if (bio->bi_size)
254 return 1;
256 slot = r10_bio->read_slot;
257 dev = r10_bio->devs[slot].devnum;
259 * this branch is our 'one mirror IO has finished' event handler:
261 update_head_pos(slot, r10_bio);
263 if (uptodate) {
265 * Set R10BIO_Uptodate in our master bio, so that
266 * we will return a good error code to the higher
267 * levels even if IO on some other mirrored buffer fails.
269 * The 'master' represents the composite IO operation to
270 * user-side. So if something waits for IO, then it will
271 * wait for the 'master' bio.
273 set_bit(R10BIO_Uptodate, &r10_bio->state);
274 raid_end_bio_io(r10_bio);
275 } else {
277 * oops, read error:
279 char b[BDEVNAME_SIZE];
280 if (printk_ratelimit())
281 printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n",
282 bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector);
283 reschedule_retry(r10_bio);
286 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
287 return 0;
290 static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
292 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
293 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
294 int slot, dev;
295 conf_t *conf = mddev_to_conf(r10_bio->mddev);
297 if (bio->bi_size)
298 return 1;
300 for (slot = 0; slot < conf->copies; slot++)
301 if (r10_bio->devs[slot].bio == bio)
302 break;
303 dev = r10_bio->devs[slot].devnum;
306 * this branch is our 'one mirror IO has finished' event handler:
308 if (!uptodate) {
309 md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
310 /* an I/O failed, we can't clear the bitmap */
311 set_bit(R10BIO_Degraded, &r10_bio->state);
312 } else
314 * Set R10BIO_Uptodate in our master bio, so that
315 * we will return a good error code for to the higher
316 * levels even if IO on some other mirrored buffer fails.
318 * The 'master' represents the composite IO operation to
319 * user-side. So if something waits for IO, then it will
320 * wait for the 'master' bio.
322 set_bit(R10BIO_Uptodate, &r10_bio->state);
324 update_head_pos(slot, r10_bio);
328 * Let's see if all mirrored write operations have finished
329 * already.
331 if (atomic_dec_and_test(&r10_bio->remaining)) {
332 /* clear the bitmap if all writes complete successfully */
333 bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
334 r10_bio->sectors,
335 !test_bit(R10BIO_Degraded, &r10_bio->state),
337 md_write_end(r10_bio->mddev);
338 raid_end_bio_io(r10_bio);
341 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
342 return 0;
347 * RAID10 layout manager
348 * Aswell as the chunksize and raid_disks count, there are two
349 * parameters: near_copies and far_copies.
350 * near_copies * far_copies must be <= raid_disks.
351 * Normally one of these will be 1.
352 * If both are 1, we get raid0.
353 * If near_copies == raid_disks, we get raid1.
355 * Chunks are layed out in raid0 style with near_copies copies of the
356 * first chunk, followed by near_copies copies of the next chunk and
357 * so on.
358 * If far_copies > 1, then after 1/far_copies of the array has been assigned
359 * as described above, we start again with a device offset of near_copies.
360 * So we effectively have another copy of the whole array further down all
361 * the drives, but with blocks on different drives.
362 * With this layout, and block is never stored twice on the one device.
364 * raid10_find_phys finds the sector offset of a given virtual sector
365 * on each device that it is on.
367 * raid10_find_virt does the reverse mapping, from a device and a
368 * sector offset to a virtual address
371 static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio)
373 int n,f;
374 sector_t sector;
375 sector_t chunk;
376 sector_t stripe;
377 int dev;
379 int slot = 0;
381 /* now calculate first sector/dev */
382 chunk = r10bio->sector >> conf->chunk_shift;
383 sector = r10bio->sector & conf->chunk_mask;
385 chunk *= conf->near_copies;
386 stripe = chunk;
387 dev = sector_div(stripe, conf->raid_disks);
388 if (conf->far_offset)
389 stripe *= conf->far_copies;
391 sector += stripe << conf->chunk_shift;
393 /* and calculate all the others */
394 for (n=0; n < conf->near_copies; n++) {
395 int d = dev;
396 sector_t s = sector;
397 r10bio->devs[slot].addr = sector;
398 r10bio->devs[slot].devnum = d;
399 slot++;
401 for (f = 1; f < conf->far_copies; f++) {
402 d += conf->near_copies;
403 if (d >= conf->raid_disks)
404 d -= conf->raid_disks;
405 s += conf->stride;
406 r10bio->devs[slot].devnum = d;
407 r10bio->devs[slot].addr = s;
408 slot++;
410 dev++;
411 if (dev >= conf->raid_disks) {
412 dev = 0;
413 sector += (conf->chunk_mask + 1);
416 BUG_ON(slot != conf->copies);
419 static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev)
421 sector_t offset, chunk, vchunk;
423 offset = sector & conf->chunk_mask;
424 if (conf->far_offset) {
425 int fc;
426 chunk = sector >> conf->chunk_shift;
427 fc = sector_div(chunk, conf->far_copies);
428 dev -= fc * conf->near_copies;
429 if (dev < 0)
430 dev += conf->raid_disks;
431 } else {
432 while (sector >= conf->stride) {
433 sector -= conf->stride;
434 if (dev < conf->near_copies)
435 dev += conf->raid_disks - conf->near_copies;
436 else
437 dev -= conf->near_copies;
439 chunk = sector >> conf->chunk_shift;
441 vchunk = chunk * conf->raid_disks + dev;
442 sector_div(vchunk, conf->near_copies);
443 return (vchunk << conf->chunk_shift) + offset;
447 * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
448 * @q: request queue
449 * @bio: the buffer head that's been built up so far
450 * @biovec: the request that could be merged to it.
452 * Return amount of bytes we can accept at this offset
453 * If near_copies == raid_disk, there are no striping issues,
454 * but in that case, the function isn't called at all.
456 static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio,
457 struct bio_vec *bio_vec)
459 mddev_t *mddev = q->queuedata;
460 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
461 int max;
462 unsigned int chunk_sectors = mddev->chunk_size >> 9;
463 unsigned int bio_sectors = bio->bi_size >> 9;
465 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
466 if (max < 0) max = 0; /* bio_add cannot handle a negative return */
467 if (max <= bio_vec->bv_len && bio_sectors == 0)
468 return bio_vec->bv_len;
469 else
470 return max;
474 * This routine returns the disk from which the requested read should
475 * be done. There is a per-array 'next expected sequential IO' sector
476 * number - if this matches on the next IO then we use the last disk.
477 * There is also a per-disk 'last know head position' sector that is
478 * maintained from IRQ contexts, both the normal and the resync IO
479 * completion handlers update this position correctly. If there is no
480 * perfect sequential match then we pick the disk whose head is closest.
482 * If there are 2 mirrors in the same 2 devices, performance degrades
483 * because position is mirror, not device based.
485 * The rdev for the device selected will have nr_pending incremented.
489 * FIXME: possibly should rethink readbalancing and do it differently
490 * depending on near_copies / far_copies geometry.
492 static int read_balance(conf_t *conf, r10bio_t *r10_bio)
494 const unsigned long this_sector = r10_bio->sector;
495 int disk, slot, nslot;
496 const int sectors = r10_bio->sectors;
497 sector_t new_distance, current_distance;
498 mdk_rdev_t *rdev;
500 raid10_find_phys(conf, r10_bio);
501 rcu_read_lock();
503 * Check if we can balance. We can balance on the whole
504 * device if no resync is going on (recovery is ok), or below
505 * the resync window. We take the first readable disk when
506 * above the resync window.
508 if (conf->mddev->recovery_cp < MaxSector
509 && (this_sector + sectors >= conf->next_resync)) {
510 /* make sure that disk is operational */
511 slot = 0;
512 disk = r10_bio->devs[slot].devnum;
514 while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
515 r10_bio->devs[slot].bio == IO_BLOCKED ||
516 !test_bit(In_sync, &rdev->flags)) {
517 slot++;
518 if (slot == conf->copies) {
519 slot = 0;
520 disk = -1;
521 break;
523 disk = r10_bio->devs[slot].devnum;
525 goto rb_out;
529 /* make sure the disk is operational */
530 slot = 0;
531 disk = r10_bio->devs[slot].devnum;
532 while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
533 r10_bio->devs[slot].bio == IO_BLOCKED ||
534 !test_bit(In_sync, &rdev->flags)) {
535 slot ++;
536 if (slot == conf->copies) {
537 disk = -1;
538 goto rb_out;
540 disk = r10_bio->devs[slot].devnum;
544 current_distance = abs(r10_bio->devs[slot].addr -
545 conf->mirrors[disk].head_position);
547 /* Find the disk whose head is closest */
549 for (nslot = slot; nslot < conf->copies; nslot++) {
550 int ndisk = r10_bio->devs[nslot].devnum;
553 if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL ||
554 r10_bio->devs[nslot].bio == IO_BLOCKED ||
555 !test_bit(In_sync, &rdev->flags))
556 continue;
558 /* This optimisation is debatable, and completely destroys
559 * sequential read speed for 'far copies' arrays. So only
560 * keep it for 'near' arrays, and review those later.
562 if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) {
563 disk = ndisk;
564 slot = nslot;
565 break;
567 new_distance = abs(r10_bio->devs[nslot].addr -
568 conf->mirrors[ndisk].head_position);
569 if (new_distance < current_distance) {
570 current_distance = new_distance;
571 disk = ndisk;
572 slot = nslot;
576 rb_out:
577 r10_bio->read_slot = slot;
578 /* conf->next_seq_sect = this_sector + sectors;*/
580 if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL)
581 atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
582 else
583 disk = -1;
584 rcu_read_unlock();
586 return disk;
589 static void unplug_slaves(mddev_t *mddev)
591 conf_t *conf = mddev_to_conf(mddev);
592 int i;
594 rcu_read_lock();
595 for (i=0; i<mddev->raid_disks; i++) {
596 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
597 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
598 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
600 atomic_inc(&rdev->nr_pending);
601 rcu_read_unlock();
603 if (r_queue->unplug_fn)
604 r_queue->unplug_fn(r_queue);
606 rdev_dec_pending(rdev, mddev);
607 rcu_read_lock();
610 rcu_read_unlock();
613 static void raid10_unplug(request_queue_t *q)
615 mddev_t *mddev = q->queuedata;
617 unplug_slaves(q->queuedata);
618 md_wakeup_thread(mddev->thread);
621 static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk,
622 sector_t *error_sector)
624 mddev_t *mddev = q->queuedata;
625 conf_t *conf = mddev_to_conf(mddev);
626 int i, ret = 0;
628 rcu_read_lock();
629 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
630 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
631 if (rdev && !test_bit(Faulty, &rdev->flags)) {
632 struct block_device *bdev = rdev->bdev;
633 request_queue_t *r_queue = bdev_get_queue(bdev);
635 if (!r_queue->issue_flush_fn)
636 ret = -EOPNOTSUPP;
637 else {
638 atomic_inc(&rdev->nr_pending);
639 rcu_read_unlock();
640 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
641 error_sector);
642 rdev_dec_pending(rdev, mddev);
643 rcu_read_lock();
647 rcu_read_unlock();
648 return ret;
651 static int raid10_congested(void *data, int bits)
653 mddev_t *mddev = data;
654 conf_t *conf = mddev_to_conf(mddev);
655 int i, ret = 0;
657 rcu_read_lock();
658 for (i = 0; i < mddev->raid_disks && ret == 0; i++) {
659 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
660 if (rdev && !test_bit(Faulty, &rdev->flags)) {
661 request_queue_t *q = bdev_get_queue(rdev->bdev);
663 ret |= bdi_congested(&q->backing_dev_info, bits);
666 rcu_read_unlock();
667 return ret;
671 /* Barriers....
672 * Sometimes we need to suspend IO while we do something else,
673 * either some resync/recovery, or reconfigure the array.
674 * To do this we raise a 'barrier'.
675 * The 'barrier' is a counter that can be raised multiple times
676 * to count how many activities are happening which preclude
677 * normal IO.
678 * We can only raise the barrier if there is no pending IO.
679 * i.e. if nr_pending == 0.
680 * We choose only to raise the barrier if no-one is waiting for the
681 * barrier to go down. This means that as soon as an IO request
682 * is ready, no other operations which require a barrier will start
683 * until the IO request has had a chance.
685 * So: regular IO calls 'wait_barrier'. When that returns there
686 * is no backgroup IO happening, It must arrange to call
687 * allow_barrier when it has finished its IO.
688 * backgroup IO calls must call raise_barrier. Once that returns
689 * there is no normal IO happeing. It must arrange to call
690 * lower_barrier when the particular background IO completes.
692 #define RESYNC_DEPTH 32
694 static void raise_barrier(conf_t *conf, int force)
696 BUG_ON(force && !conf->barrier);
697 spin_lock_irq(&conf->resync_lock);
699 /* Wait until no block IO is waiting (unless 'force') */
700 wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
701 conf->resync_lock,
702 raid10_unplug(conf->mddev->queue));
704 /* block any new IO from starting */
705 conf->barrier++;
707 /* No wait for all pending IO to complete */
708 wait_event_lock_irq(conf->wait_barrier,
709 !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
710 conf->resync_lock,
711 raid10_unplug(conf->mddev->queue));
713 spin_unlock_irq(&conf->resync_lock);
716 static void lower_barrier(conf_t *conf)
718 unsigned long flags;
719 spin_lock_irqsave(&conf->resync_lock, flags);
720 conf->barrier--;
721 spin_unlock_irqrestore(&conf->resync_lock, flags);
722 wake_up(&conf->wait_barrier);
725 static void wait_barrier(conf_t *conf)
727 spin_lock_irq(&conf->resync_lock);
728 if (conf->barrier) {
729 conf->nr_waiting++;
730 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
731 conf->resync_lock,
732 raid10_unplug(conf->mddev->queue));
733 conf->nr_waiting--;
735 conf->nr_pending++;
736 spin_unlock_irq(&conf->resync_lock);
739 static void allow_barrier(conf_t *conf)
741 unsigned long flags;
742 spin_lock_irqsave(&conf->resync_lock, flags);
743 conf->nr_pending--;
744 spin_unlock_irqrestore(&conf->resync_lock, flags);
745 wake_up(&conf->wait_barrier);
748 static void freeze_array(conf_t *conf)
750 /* stop syncio and normal IO and wait for everything to
751 * go quiet.
752 * We increment barrier and nr_waiting, and then
753 * wait until barrier+nr_pending match nr_queued+2
755 spin_lock_irq(&conf->resync_lock);
756 conf->barrier++;
757 conf->nr_waiting++;
758 wait_event_lock_irq(conf->wait_barrier,
759 conf->barrier+conf->nr_pending == conf->nr_queued+2,
760 conf->resync_lock,
761 raid10_unplug(conf->mddev->queue));
762 spin_unlock_irq(&conf->resync_lock);
765 static void unfreeze_array(conf_t *conf)
767 /* reverse the effect of the freeze */
768 spin_lock_irq(&conf->resync_lock);
769 conf->barrier--;
770 conf->nr_waiting--;
771 wake_up(&conf->wait_barrier);
772 spin_unlock_irq(&conf->resync_lock);
775 static int make_request(request_queue_t *q, struct bio * bio)
777 mddev_t *mddev = q->queuedata;
778 conf_t *conf = mddev_to_conf(mddev);
779 mirror_info_t *mirror;
780 r10bio_t *r10_bio;
781 struct bio *read_bio;
782 int i;
783 int chunk_sects = conf->chunk_mask + 1;
784 const int rw = bio_data_dir(bio);
785 const int do_sync = bio_sync(bio);
786 struct bio_list bl;
787 unsigned long flags;
789 if (unlikely(bio_barrier(bio))) {
790 bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
791 return 0;
794 /* If this request crosses a chunk boundary, we need to
795 * split it. This will only happen for 1 PAGE (or less) requests.
797 if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9)
798 > chunk_sects &&
799 conf->near_copies < conf->raid_disks)) {
800 struct bio_pair *bp;
801 /* Sanity check -- queue functions should prevent this happening */
802 if (bio->bi_vcnt != 1 ||
803 bio->bi_idx != 0)
804 goto bad_map;
805 /* This is a one page bio that upper layers
806 * refuse to split for us, so we need to split it.
808 bp = bio_split(bio, bio_split_pool,
809 chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
810 if (make_request(q, &bp->bio1))
811 generic_make_request(&bp->bio1);
812 if (make_request(q, &bp->bio2))
813 generic_make_request(&bp->bio2);
815 bio_pair_release(bp);
816 return 0;
817 bad_map:
818 printk("raid10_make_request bug: can't convert block across chunks"
819 " or bigger than %dk %llu %d\n", chunk_sects/2,
820 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
822 bio_io_error(bio, bio->bi_size);
823 return 0;
826 md_write_start(mddev, bio);
829 * Register the new request and wait if the reconstruction
830 * thread has put up a bar for new requests.
831 * Continue immediately if no resync is active currently.
833 wait_barrier(conf);
835 disk_stat_inc(mddev->gendisk, ios[rw]);
836 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
838 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
840 r10_bio->master_bio = bio;
841 r10_bio->sectors = bio->bi_size >> 9;
843 r10_bio->mddev = mddev;
844 r10_bio->sector = bio->bi_sector;
845 r10_bio->state = 0;
847 if (rw == READ) {
849 * read balancing logic:
851 int disk = read_balance(conf, r10_bio);
852 int slot = r10_bio->read_slot;
853 if (disk < 0) {
854 raid_end_bio_io(r10_bio);
855 return 0;
857 mirror = conf->mirrors + disk;
859 read_bio = bio_clone(bio, GFP_NOIO);
861 r10_bio->devs[slot].bio = read_bio;
863 read_bio->bi_sector = r10_bio->devs[slot].addr +
864 mirror->rdev->data_offset;
865 read_bio->bi_bdev = mirror->rdev->bdev;
866 read_bio->bi_end_io = raid10_end_read_request;
867 read_bio->bi_rw = READ | do_sync;
868 read_bio->bi_private = r10_bio;
870 generic_make_request(read_bio);
871 return 0;
875 * WRITE:
877 /* first select target devices under spinlock and
878 * inc refcount on their rdev. Record them by setting
879 * bios[x] to bio
881 raid10_find_phys(conf, r10_bio);
882 rcu_read_lock();
883 for (i = 0; i < conf->copies; i++) {
884 int d = r10_bio->devs[i].devnum;
885 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
886 if (rdev &&
887 !test_bit(Faulty, &rdev->flags)) {
888 atomic_inc(&rdev->nr_pending);
889 r10_bio->devs[i].bio = bio;
890 } else {
891 r10_bio->devs[i].bio = NULL;
892 set_bit(R10BIO_Degraded, &r10_bio->state);
895 rcu_read_unlock();
897 atomic_set(&r10_bio->remaining, 0);
899 bio_list_init(&bl);
900 for (i = 0; i < conf->copies; i++) {
901 struct bio *mbio;
902 int d = r10_bio->devs[i].devnum;
903 if (!r10_bio->devs[i].bio)
904 continue;
906 mbio = bio_clone(bio, GFP_NOIO);
907 r10_bio->devs[i].bio = mbio;
909 mbio->bi_sector = r10_bio->devs[i].addr+
910 conf->mirrors[d].rdev->data_offset;
911 mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
912 mbio->bi_end_io = raid10_end_write_request;
913 mbio->bi_rw = WRITE | do_sync;
914 mbio->bi_private = r10_bio;
916 atomic_inc(&r10_bio->remaining);
917 bio_list_add(&bl, mbio);
920 bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0);
921 spin_lock_irqsave(&conf->device_lock, flags);
922 bio_list_merge(&conf->pending_bio_list, &bl);
923 blk_plug_device(mddev->queue);
924 spin_unlock_irqrestore(&conf->device_lock, flags);
926 if (do_sync)
927 md_wakeup_thread(mddev->thread);
929 return 0;
932 static void status(struct seq_file *seq, mddev_t *mddev)
934 conf_t *conf = mddev_to_conf(mddev);
935 int i;
937 if (conf->near_copies < conf->raid_disks)
938 seq_printf(seq, " %dK chunks", mddev->chunk_size/1024);
939 if (conf->near_copies > 1)
940 seq_printf(seq, " %d near-copies", conf->near_copies);
941 if (conf->far_copies > 1) {
942 if (conf->far_offset)
943 seq_printf(seq, " %d offset-copies", conf->far_copies);
944 else
945 seq_printf(seq, " %d far-copies", conf->far_copies);
947 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
948 conf->raid_disks - mddev->degraded);
949 for (i = 0; i < conf->raid_disks; i++)
950 seq_printf(seq, "%s",
951 conf->mirrors[i].rdev &&
952 test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
953 seq_printf(seq, "]");
956 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
958 char b[BDEVNAME_SIZE];
959 conf_t *conf = mddev_to_conf(mddev);
962 * If it is not operational, then we have already marked it as dead
963 * else if it is the last working disks, ignore the error, let the
964 * next level up know.
965 * else mark the drive as failed
967 if (test_bit(In_sync, &rdev->flags)
968 && conf->raid_disks-mddev->degraded == 1)
970 * Don't fail the drive, just return an IO error.
971 * The test should really be more sophisticated than
972 * "working_disks == 1", but it isn't critical, and
973 * can wait until we do more sophisticated "is the drive
974 * really dead" tests...
976 return;
977 if (test_and_clear_bit(In_sync, &rdev->flags)) {
978 unsigned long flags;
979 spin_lock_irqsave(&conf->device_lock, flags);
980 mddev->degraded++;
981 spin_unlock_irqrestore(&conf->device_lock, flags);
983 * if recovery is running, make sure it aborts.
985 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
987 set_bit(Faulty, &rdev->flags);
988 set_bit(MD_CHANGE_DEVS, &mddev->flags);
989 printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n"
990 " Operation continuing on %d devices\n",
991 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
994 static void print_conf(conf_t *conf)
996 int i;
997 mirror_info_t *tmp;
999 printk("RAID10 conf printout:\n");
1000 if (!conf) {
1001 printk("(!conf)\n");
1002 return;
1004 printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1005 conf->raid_disks);
1007 for (i = 0; i < conf->raid_disks; i++) {
1008 char b[BDEVNAME_SIZE];
1009 tmp = conf->mirrors + i;
1010 if (tmp->rdev)
1011 printk(" disk %d, wo:%d, o:%d, dev:%s\n",
1012 i, !test_bit(In_sync, &tmp->rdev->flags),
1013 !test_bit(Faulty, &tmp->rdev->flags),
1014 bdevname(tmp->rdev->bdev,b));
1018 static void close_sync(conf_t *conf)
1020 wait_barrier(conf);
1021 allow_barrier(conf);
1023 mempool_destroy(conf->r10buf_pool);
1024 conf->r10buf_pool = NULL;
1027 /* check if there are enough drives for
1028 * every block to appear on atleast one
1030 static int enough(conf_t *conf)
1032 int first = 0;
1034 do {
1035 int n = conf->copies;
1036 int cnt = 0;
1037 while (n--) {
1038 if (conf->mirrors[first].rdev)
1039 cnt++;
1040 first = (first+1) % conf->raid_disks;
1042 if (cnt == 0)
1043 return 0;
1044 } while (first != 0);
1045 return 1;
1048 static int raid10_spare_active(mddev_t *mddev)
1050 int i;
1051 conf_t *conf = mddev->private;
1052 mirror_info_t *tmp;
1055 * Find all non-in_sync disks within the RAID10 configuration
1056 * and mark them in_sync
1058 for (i = 0; i < conf->raid_disks; i++) {
1059 tmp = conf->mirrors + i;
1060 if (tmp->rdev
1061 && !test_bit(Faulty, &tmp->rdev->flags)
1062 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1063 unsigned long flags;
1064 spin_lock_irqsave(&conf->device_lock, flags);
1065 mddev->degraded--;
1066 spin_unlock_irqrestore(&conf->device_lock, flags);
1070 print_conf(conf);
1071 return 0;
1075 static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1077 conf_t *conf = mddev->private;
1078 int found = 0;
1079 int mirror;
1080 mirror_info_t *p;
1082 if (mddev->recovery_cp < MaxSector)
1083 /* only hot-add to in-sync arrays, as recovery is
1084 * very different from resync
1086 return 0;
1087 if (!enough(conf))
1088 return 0;
1090 if (rdev->saved_raid_disk >= 0 &&
1091 conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1092 mirror = rdev->saved_raid_disk;
1093 else
1094 mirror = 0;
1095 for ( ; mirror < mddev->raid_disks; mirror++)
1096 if ( !(p=conf->mirrors+mirror)->rdev) {
1098 blk_queue_stack_limits(mddev->queue,
1099 rdev->bdev->bd_disk->queue);
1100 /* as we don't honour merge_bvec_fn, we must never risk
1101 * violating it, so limit ->max_sector to one PAGE, as
1102 * a one page request is never in violation.
1104 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1105 mddev->queue->max_sectors > (PAGE_SIZE>>9))
1106 mddev->queue->max_sectors = (PAGE_SIZE>>9);
1108 p->head_position = 0;
1109 rdev->raid_disk = mirror;
1110 found = 1;
1111 if (rdev->saved_raid_disk != mirror)
1112 conf->fullsync = 1;
1113 rcu_assign_pointer(p->rdev, rdev);
1114 break;
1117 print_conf(conf);
1118 return found;
1121 static int raid10_remove_disk(mddev_t *mddev, int number)
1123 conf_t *conf = mddev->private;
1124 int err = 0;
1125 mdk_rdev_t *rdev;
1126 mirror_info_t *p = conf->mirrors+ number;
1128 print_conf(conf);
1129 rdev = p->rdev;
1130 if (rdev) {
1131 if (test_bit(In_sync, &rdev->flags) ||
1132 atomic_read(&rdev->nr_pending)) {
1133 err = -EBUSY;
1134 goto abort;
1136 p->rdev = NULL;
1137 synchronize_rcu();
1138 if (atomic_read(&rdev->nr_pending)) {
1139 /* lost the race, try later */
1140 err = -EBUSY;
1141 p->rdev = rdev;
1144 abort:
1146 print_conf(conf);
1147 return err;
1151 static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
1153 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
1154 conf_t *conf = mddev_to_conf(r10_bio->mddev);
1155 int i,d;
1157 if (bio->bi_size)
1158 return 1;
1160 for (i=0; i<conf->copies; i++)
1161 if (r10_bio->devs[i].bio == bio)
1162 break;
1163 BUG_ON(i == conf->copies);
1164 update_head_pos(i, r10_bio);
1165 d = r10_bio->devs[i].devnum;
1167 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1168 set_bit(R10BIO_Uptodate, &r10_bio->state);
1169 else {
1170 atomic_add(r10_bio->sectors,
1171 &conf->mirrors[d].rdev->corrected_errors);
1172 if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
1173 md_error(r10_bio->mddev,
1174 conf->mirrors[d].rdev);
1177 /* for reconstruct, we always reschedule after a read.
1178 * for resync, only after all reads
1180 if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1181 atomic_dec_and_test(&r10_bio->remaining)) {
1182 /* we have read all the blocks,
1183 * do the comparison in process context in raid10d
1185 reschedule_retry(r10_bio);
1187 rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1188 return 0;
1191 static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
1193 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1194 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
1195 mddev_t *mddev = r10_bio->mddev;
1196 conf_t *conf = mddev_to_conf(mddev);
1197 int i,d;
1199 if (bio->bi_size)
1200 return 1;
1202 for (i = 0; i < conf->copies; i++)
1203 if (r10_bio->devs[i].bio == bio)
1204 break;
1205 d = r10_bio->devs[i].devnum;
1207 if (!uptodate)
1208 md_error(mddev, conf->mirrors[d].rdev);
1209 update_head_pos(i, r10_bio);
1211 while (atomic_dec_and_test(&r10_bio->remaining)) {
1212 if (r10_bio->master_bio == NULL) {
1213 /* the primary of several recovery bios */
1214 md_done_sync(mddev, r10_bio->sectors, 1);
1215 put_buf(r10_bio);
1216 break;
1217 } else {
1218 r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio;
1219 put_buf(r10_bio);
1220 r10_bio = r10_bio2;
1223 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1224 return 0;
1228 * Note: sync and recover and handled very differently for raid10
1229 * This code is for resync.
1230 * For resync, we read through virtual addresses and read all blocks.
1231 * If there is any error, we schedule a write. The lowest numbered
1232 * drive is authoritative.
1233 * However requests come for physical address, so we need to map.
1234 * For every physical address there are raid_disks/copies virtual addresses,
1235 * which is always are least one, but is not necessarly an integer.
1236 * This means that a physical address can span multiple chunks, so we may
1237 * have to submit multiple io requests for a single sync request.
1240 * We check if all blocks are in-sync and only write to blocks that
1241 * aren't in sync
1243 static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio)
1245 conf_t *conf = mddev_to_conf(mddev);
1246 int i, first;
1247 struct bio *tbio, *fbio;
1249 atomic_set(&r10_bio->remaining, 1);
1251 /* find the first device with a block */
1252 for (i=0; i<conf->copies; i++)
1253 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
1254 break;
1256 if (i == conf->copies)
1257 goto done;
1259 first = i;
1260 fbio = r10_bio->devs[i].bio;
1262 /* now find blocks with errors */
1263 for (i=0 ; i < conf->copies ; i++) {
1264 int j, d;
1265 int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
1267 tbio = r10_bio->devs[i].bio;
1269 if (tbio->bi_end_io != end_sync_read)
1270 continue;
1271 if (i == first)
1272 continue;
1273 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) {
1274 /* We know that the bi_io_vec layout is the same for
1275 * both 'first' and 'i', so we just compare them.
1276 * All vec entries are PAGE_SIZE;
1278 for (j = 0; j < vcnt; j++)
1279 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
1280 page_address(tbio->bi_io_vec[j].bv_page),
1281 PAGE_SIZE))
1282 break;
1283 if (j == vcnt)
1284 continue;
1285 mddev->resync_mismatches += r10_bio->sectors;
1287 if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
1288 /* Don't fix anything. */
1289 continue;
1290 /* Ok, we need to write this bio
1291 * First we need to fixup bv_offset, bv_len and
1292 * bi_vecs, as the read request might have corrupted these
1294 tbio->bi_vcnt = vcnt;
1295 tbio->bi_size = r10_bio->sectors << 9;
1296 tbio->bi_idx = 0;
1297 tbio->bi_phys_segments = 0;
1298 tbio->bi_hw_segments = 0;
1299 tbio->bi_hw_front_size = 0;
1300 tbio->bi_hw_back_size = 0;
1301 tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1302 tbio->bi_flags |= 1 << BIO_UPTODATE;
1303 tbio->bi_next = NULL;
1304 tbio->bi_rw = WRITE;
1305 tbio->bi_private = r10_bio;
1306 tbio->bi_sector = r10_bio->devs[i].addr;
1308 for (j=0; j < vcnt ; j++) {
1309 tbio->bi_io_vec[j].bv_offset = 0;
1310 tbio->bi_io_vec[j].bv_len = PAGE_SIZE;
1312 memcpy(page_address(tbio->bi_io_vec[j].bv_page),
1313 page_address(fbio->bi_io_vec[j].bv_page),
1314 PAGE_SIZE);
1316 tbio->bi_end_io = end_sync_write;
1318 d = r10_bio->devs[i].devnum;
1319 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1320 atomic_inc(&r10_bio->remaining);
1321 md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
1323 tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
1324 tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
1325 generic_make_request(tbio);
1328 done:
1329 if (atomic_dec_and_test(&r10_bio->remaining)) {
1330 md_done_sync(mddev, r10_bio->sectors, 1);
1331 put_buf(r10_bio);
1336 * Now for the recovery code.
1337 * Recovery happens across physical sectors.
1338 * We recover all non-is_sync drives by finding the virtual address of
1339 * each, and then choose a working drive that also has that virt address.
1340 * There is a separate r10_bio for each non-in_sync drive.
1341 * Only the first two slots are in use. The first for reading,
1342 * The second for writing.
1346 static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
1348 conf_t *conf = mddev_to_conf(mddev);
1349 int i, d;
1350 struct bio *bio, *wbio;
1353 /* move the pages across to the second bio
1354 * and submit the write request
1356 bio = r10_bio->devs[0].bio;
1357 wbio = r10_bio->devs[1].bio;
1358 for (i=0; i < wbio->bi_vcnt; i++) {
1359 struct page *p = bio->bi_io_vec[i].bv_page;
1360 bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page;
1361 wbio->bi_io_vec[i].bv_page = p;
1363 d = r10_bio->devs[1].devnum;
1365 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1366 md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
1367 if (test_bit(R10BIO_Uptodate, &r10_bio->state))
1368 generic_make_request(wbio);
1369 else
1370 bio_endio(wbio, wbio->bi_size, -EIO);
1375 * This is a kernel thread which:
1377 * 1. Retries failed read operations on working mirrors.
1378 * 2. Updates the raid superblock when problems encounter.
1379 * 3. Performs writes following reads for array synchronising.
1382 static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
1384 int sect = 0; /* Offset from r10_bio->sector */
1385 int sectors = r10_bio->sectors;
1386 mdk_rdev_t*rdev;
1387 while(sectors) {
1388 int s = sectors;
1389 int sl = r10_bio->read_slot;
1390 int success = 0;
1391 int start;
1393 if (s > (PAGE_SIZE>>9))
1394 s = PAGE_SIZE >> 9;
1396 rcu_read_lock();
1397 do {
1398 int d = r10_bio->devs[sl].devnum;
1399 rdev = rcu_dereference(conf->mirrors[d].rdev);
1400 if (rdev &&
1401 test_bit(In_sync, &rdev->flags)) {
1402 atomic_inc(&rdev->nr_pending);
1403 rcu_read_unlock();
1404 success = sync_page_io(rdev->bdev,
1405 r10_bio->devs[sl].addr +
1406 sect + rdev->data_offset,
1407 s<<9,
1408 conf->tmppage, READ);
1409 rdev_dec_pending(rdev, mddev);
1410 rcu_read_lock();
1411 if (success)
1412 break;
1414 sl++;
1415 if (sl == conf->copies)
1416 sl = 0;
1417 } while (!success && sl != r10_bio->read_slot);
1418 rcu_read_unlock();
1420 if (!success) {
1421 /* Cannot read from anywhere -- bye bye array */
1422 int dn = r10_bio->devs[r10_bio->read_slot].devnum;
1423 md_error(mddev, conf->mirrors[dn].rdev);
1424 break;
1427 start = sl;
1428 /* write it back and re-read */
1429 rcu_read_lock();
1430 while (sl != r10_bio->read_slot) {
1431 int d;
1432 if (sl==0)
1433 sl = conf->copies;
1434 sl--;
1435 d = r10_bio->devs[sl].devnum;
1436 rdev = rcu_dereference(conf->mirrors[d].rdev);
1437 if (rdev &&
1438 test_bit(In_sync, &rdev->flags)) {
1439 atomic_inc(&rdev->nr_pending);
1440 rcu_read_unlock();
1441 atomic_add(s, &rdev->corrected_errors);
1442 if (sync_page_io(rdev->bdev,
1443 r10_bio->devs[sl].addr +
1444 sect + rdev->data_offset,
1445 s<<9, conf->tmppage, WRITE)
1446 == 0)
1447 /* Well, this device is dead */
1448 md_error(mddev, rdev);
1449 rdev_dec_pending(rdev, mddev);
1450 rcu_read_lock();
1453 sl = start;
1454 while (sl != r10_bio->read_slot) {
1455 int d;
1456 if (sl==0)
1457 sl = conf->copies;
1458 sl--;
1459 d = r10_bio->devs[sl].devnum;
1460 rdev = rcu_dereference(conf->mirrors[d].rdev);
1461 if (rdev &&
1462 test_bit(In_sync, &rdev->flags)) {
1463 char b[BDEVNAME_SIZE];
1464 atomic_inc(&rdev->nr_pending);
1465 rcu_read_unlock();
1466 if (sync_page_io(rdev->bdev,
1467 r10_bio->devs[sl].addr +
1468 sect + rdev->data_offset,
1469 s<<9, conf->tmppage, READ) == 0)
1470 /* Well, this device is dead */
1471 md_error(mddev, rdev);
1472 else
1473 printk(KERN_INFO
1474 "raid10:%s: read error corrected"
1475 " (%d sectors at %llu on %s)\n",
1476 mdname(mddev), s,
1477 (unsigned long long)(sect+
1478 rdev->data_offset),
1479 bdevname(rdev->bdev, b));
1481 rdev_dec_pending(rdev, mddev);
1482 rcu_read_lock();
1485 rcu_read_unlock();
1487 sectors -= s;
1488 sect += s;
1492 static void raid10d(mddev_t *mddev)
1494 r10bio_t *r10_bio;
1495 struct bio *bio;
1496 unsigned long flags;
1497 conf_t *conf = mddev_to_conf(mddev);
1498 struct list_head *head = &conf->retry_list;
1499 int unplug=0;
1500 mdk_rdev_t *rdev;
1502 md_check_recovery(mddev);
1504 for (;;) {
1505 char b[BDEVNAME_SIZE];
1506 spin_lock_irqsave(&conf->device_lock, flags);
1508 if (conf->pending_bio_list.head) {
1509 bio = bio_list_get(&conf->pending_bio_list);
1510 blk_remove_plug(mddev->queue);
1511 spin_unlock_irqrestore(&conf->device_lock, flags);
1512 /* flush any pending bitmap writes to disk before proceeding w/ I/O */
1513 if (bitmap_unplug(mddev->bitmap) != 0)
1514 printk("%s: bitmap file write failed!\n", mdname(mddev));
1516 while (bio) { /* submit pending writes */
1517 struct bio *next = bio->bi_next;
1518 bio->bi_next = NULL;
1519 generic_make_request(bio);
1520 bio = next;
1522 unplug = 1;
1524 continue;
1527 if (list_empty(head))
1528 break;
1529 r10_bio = list_entry(head->prev, r10bio_t, retry_list);
1530 list_del(head->prev);
1531 conf->nr_queued--;
1532 spin_unlock_irqrestore(&conf->device_lock, flags);
1534 mddev = r10_bio->mddev;
1535 conf = mddev_to_conf(mddev);
1536 if (test_bit(R10BIO_IsSync, &r10_bio->state)) {
1537 sync_request_write(mddev, r10_bio);
1538 unplug = 1;
1539 } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) {
1540 recovery_request_write(mddev, r10_bio);
1541 unplug = 1;
1542 } else {
1543 int mirror;
1544 /* we got a read error. Maybe the drive is bad. Maybe just
1545 * the block and we can fix it.
1546 * We freeze all other IO, and try reading the block from
1547 * other devices. When we find one, we re-write
1548 * and check it that fixes the read error.
1549 * This is all done synchronously while the array is
1550 * frozen.
1552 if (mddev->ro == 0) {
1553 freeze_array(conf);
1554 fix_read_error(conf, mddev, r10_bio);
1555 unfreeze_array(conf);
1558 bio = r10_bio->devs[r10_bio->read_slot].bio;
1559 r10_bio->devs[r10_bio->read_slot].bio =
1560 mddev->ro ? IO_BLOCKED : NULL;
1561 bio_put(bio);
1562 mirror = read_balance(conf, r10_bio);
1563 if (mirror == -1) {
1564 printk(KERN_ALERT "raid10: %s: unrecoverable I/O"
1565 " read error for block %llu\n",
1566 bdevname(bio->bi_bdev,b),
1567 (unsigned long long)r10_bio->sector);
1568 raid_end_bio_io(r10_bio);
1569 } else {
1570 const int do_sync = bio_sync(r10_bio->master_bio);
1571 rdev = conf->mirrors[mirror].rdev;
1572 if (printk_ratelimit())
1573 printk(KERN_ERR "raid10: %s: redirecting sector %llu to"
1574 " another mirror\n",
1575 bdevname(rdev->bdev,b),
1576 (unsigned long long)r10_bio->sector);
1577 bio = bio_clone(r10_bio->master_bio, GFP_NOIO);
1578 r10_bio->devs[r10_bio->read_slot].bio = bio;
1579 bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr
1580 + rdev->data_offset;
1581 bio->bi_bdev = rdev->bdev;
1582 bio->bi_rw = READ | do_sync;
1583 bio->bi_private = r10_bio;
1584 bio->bi_end_io = raid10_end_read_request;
1585 unplug = 1;
1586 generic_make_request(bio);
1590 spin_unlock_irqrestore(&conf->device_lock, flags);
1591 if (unplug)
1592 unplug_slaves(mddev);
1596 static int init_resync(conf_t *conf)
1598 int buffs;
1600 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1601 BUG_ON(conf->r10buf_pool);
1602 conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
1603 if (!conf->r10buf_pool)
1604 return -ENOMEM;
1605 conf->next_resync = 0;
1606 return 0;
1610 * perform a "sync" on one "block"
1612 * We need to make sure that no normal I/O request - particularly write
1613 * requests - conflict with active sync requests.
1615 * This is achieved by tracking pending requests and a 'barrier' concept
1616 * that can be installed to exclude normal IO requests.
1618 * Resync and recovery are handled very differently.
1619 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
1621 * For resync, we iterate over virtual addresses, read all copies,
1622 * and update if there are differences. If only one copy is live,
1623 * skip it.
1624 * For recovery, we iterate over physical addresses, read a good
1625 * value for each non-in_sync drive, and over-write.
1627 * So, for recovery we may have several outstanding complex requests for a
1628 * given address, one for each out-of-sync device. We model this by allocating
1629 * a number of r10_bio structures, one for each out-of-sync device.
1630 * As we setup these structures, we collect all bio's together into a list
1631 * which we then process collectively to add pages, and then process again
1632 * to pass to generic_make_request.
1634 * The r10_bio structures are linked using a borrowed master_bio pointer.
1635 * This link is counted in ->remaining. When the r10_bio that points to NULL
1636 * has its remaining count decremented to 0, the whole complex operation
1637 * is complete.
1641 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1643 conf_t *conf = mddev_to_conf(mddev);
1644 r10bio_t *r10_bio;
1645 struct bio *biolist = NULL, *bio;
1646 sector_t max_sector, nr_sectors;
1647 int disk;
1648 int i;
1649 int max_sync;
1650 int sync_blocks;
1652 sector_t sectors_skipped = 0;
1653 int chunks_skipped = 0;
1655 if (!conf->r10buf_pool)
1656 if (init_resync(conf))
1657 return 0;
1659 skipped:
1660 max_sector = mddev->size << 1;
1661 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
1662 max_sector = mddev->resync_max_sectors;
1663 if (sector_nr >= max_sector) {
1664 /* If we aborted, we need to abort the
1665 * sync on the 'current' bitmap chucks (there can
1666 * be several when recovering multiple devices).
1667 * as we may have started syncing it but not finished.
1668 * We can find the current address in
1669 * mddev->curr_resync, but for recovery,
1670 * we need to convert that to several
1671 * virtual addresses.
1673 if (mddev->curr_resync < max_sector) { /* aborted */
1674 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
1675 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1676 &sync_blocks, 1);
1677 else for (i=0; i<conf->raid_disks; i++) {
1678 sector_t sect =
1679 raid10_find_virt(conf, mddev->curr_resync, i);
1680 bitmap_end_sync(mddev->bitmap, sect,
1681 &sync_blocks, 1);
1683 } else /* completed sync */
1684 conf->fullsync = 0;
1686 bitmap_close_sync(mddev->bitmap);
1687 close_sync(conf);
1688 *skipped = 1;
1689 return sectors_skipped;
1691 if (chunks_skipped >= conf->raid_disks) {
1692 /* if there has been nothing to do on any drive,
1693 * then there is nothing to do at all..
1695 *skipped = 1;
1696 return (max_sector - sector_nr) + sectors_skipped;
1699 /* make sure whole request will fit in a chunk - if chunks
1700 * are meaningful
1702 if (conf->near_copies < conf->raid_disks &&
1703 max_sector > (sector_nr | conf->chunk_mask))
1704 max_sector = (sector_nr | conf->chunk_mask) + 1;
1706 * If there is non-resync activity waiting for us then
1707 * put in a delay to throttle resync.
1709 if (!go_faster && conf->nr_waiting)
1710 msleep_interruptible(1000);
1712 /* Again, very different code for resync and recovery.
1713 * Both must result in an r10bio with a list of bios that
1714 * have bi_end_io, bi_sector, bi_bdev set,
1715 * and bi_private set to the r10bio.
1716 * For recovery, we may actually create several r10bios
1717 * with 2 bios in each, that correspond to the bios in the main one.
1718 * In this case, the subordinate r10bios link back through a
1719 * borrowed master_bio pointer, and the counter in the master
1720 * includes a ref from each subordinate.
1722 /* First, we decide what to do and set ->bi_end_io
1723 * To end_sync_read if we want to read, and
1724 * end_sync_write if we will want to write.
1727 max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
1728 if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
1729 /* recovery... the complicated one */
1730 int i, j, k;
1731 r10_bio = NULL;
1733 for (i=0 ; i<conf->raid_disks; i++)
1734 if (conf->mirrors[i].rdev &&
1735 !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) {
1736 int still_degraded = 0;
1737 /* want to reconstruct this device */
1738 r10bio_t *rb2 = r10_bio;
1739 sector_t sect = raid10_find_virt(conf, sector_nr, i);
1740 int must_sync;
1741 /* Unless we are doing a full sync, we only need
1742 * to recover the block if it is set in the bitmap
1744 must_sync = bitmap_start_sync(mddev->bitmap, sect,
1745 &sync_blocks, 1);
1746 if (sync_blocks < max_sync)
1747 max_sync = sync_blocks;
1748 if (!must_sync &&
1749 !conf->fullsync) {
1750 /* yep, skip the sync_blocks here, but don't assume
1751 * that there will never be anything to do here
1753 chunks_skipped = -1;
1754 continue;
1757 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
1758 raise_barrier(conf, rb2 != NULL);
1759 atomic_set(&r10_bio->remaining, 0);
1761 r10_bio->master_bio = (struct bio*)rb2;
1762 if (rb2)
1763 atomic_inc(&rb2->remaining);
1764 r10_bio->mddev = mddev;
1765 set_bit(R10BIO_IsRecover, &r10_bio->state);
1766 r10_bio->sector = sect;
1768 raid10_find_phys(conf, r10_bio);
1769 /* Need to check if this section will still be
1770 * degraded
1772 for (j=0; j<conf->copies;j++) {
1773 int d = r10_bio->devs[j].devnum;
1774 if (conf->mirrors[d].rdev == NULL ||
1775 test_bit(Faulty, &conf->mirrors[d].rdev->flags)) {
1776 still_degraded = 1;
1777 break;
1780 must_sync = bitmap_start_sync(mddev->bitmap, sect,
1781 &sync_blocks, still_degraded);
1783 for (j=0; j<conf->copies;j++) {
1784 int d = r10_bio->devs[j].devnum;
1785 if (conf->mirrors[d].rdev &&
1786 test_bit(In_sync, &conf->mirrors[d].rdev->flags)) {
1787 /* This is where we read from */
1788 bio = r10_bio->devs[0].bio;
1789 bio->bi_next = biolist;
1790 biolist = bio;
1791 bio->bi_private = r10_bio;
1792 bio->bi_end_io = end_sync_read;
1793 bio->bi_rw = READ;
1794 bio->bi_sector = r10_bio->devs[j].addr +
1795 conf->mirrors[d].rdev->data_offset;
1796 bio->bi_bdev = conf->mirrors[d].rdev->bdev;
1797 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1798 atomic_inc(&r10_bio->remaining);
1799 /* and we write to 'i' */
1801 for (k=0; k<conf->copies; k++)
1802 if (r10_bio->devs[k].devnum == i)
1803 break;
1804 BUG_ON(k == conf->copies);
1805 bio = r10_bio->devs[1].bio;
1806 bio->bi_next = biolist;
1807 biolist = bio;
1808 bio->bi_private = r10_bio;
1809 bio->bi_end_io = end_sync_write;
1810 bio->bi_rw = WRITE;
1811 bio->bi_sector = r10_bio->devs[k].addr +
1812 conf->mirrors[i].rdev->data_offset;
1813 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1815 r10_bio->devs[0].devnum = d;
1816 r10_bio->devs[1].devnum = i;
1818 break;
1821 if (j == conf->copies) {
1822 /* Cannot recover, so abort the recovery */
1823 put_buf(r10_bio);
1824 r10_bio = rb2;
1825 if (!test_and_set_bit(MD_RECOVERY_ERR, &mddev->recovery))
1826 printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n",
1827 mdname(mddev));
1828 break;
1831 if (biolist == NULL) {
1832 while (r10_bio) {
1833 r10bio_t *rb2 = r10_bio;
1834 r10_bio = (r10bio_t*) rb2->master_bio;
1835 rb2->master_bio = NULL;
1836 put_buf(rb2);
1838 goto giveup;
1840 } else {
1841 /* resync. Schedule a read for every block at this virt offset */
1842 int count = 0;
1844 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1845 &sync_blocks, mddev->degraded) &&
1846 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1847 /* We can skip this block */
1848 *skipped = 1;
1849 return sync_blocks + sectors_skipped;
1851 if (sync_blocks < max_sync)
1852 max_sync = sync_blocks;
1853 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
1855 r10_bio->mddev = mddev;
1856 atomic_set(&r10_bio->remaining, 0);
1857 raise_barrier(conf, 0);
1858 conf->next_resync = sector_nr;
1860 r10_bio->master_bio = NULL;
1861 r10_bio->sector = sector_nr;
1862 set_bit(R10BIO_IsSync, &r10_bio->state);
1863 raid10_find_phys(conf, r10_bio);
1864 r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1;
1866 for (i=0; i<conf->copies; i++) {
1867 int d = r10_bio->devs[i].devnum;
1868 bio = r10_bio->devs[i].bio;
1869 bio->bi_end_io = NULL;
1870 if (conf->mirrors[d].rdev == NULL ||
1871 test_bit(Faulty, &conf->mirrors[d].rdev->flags))
1872 continue;
1873 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1874 atomic_inc(&r10_bio->remaining);
1875 bio->bi_next = biolist;
1876 biolist = bio;
1877 bio->bi_private = r10_bio;
1878 bio->bi_end_io = end_sync_read;
1879 bio->bi_rw = READ;
1880 bio->bi_sector = r10_bio->devs[i].addr +
1881 conf->mirrors[d].rdev->data_offset;
1882 bio->bi_bdev = conf->mirrors[d].rdev->bdev;
1883 count++;
1886 if (count < 2) {
1887 for (i=0; i<conf->copies; i++) {
1888 int d = r10_bio->devs[i].devnum;
1889 if (r10_bio->devs[i].bio->bi_end_io)
1890 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1892 put_buf(r10_bio);
1893 biolist = NULL;
1894 goto giveup;
1898 for (bio = biolist; bio ; bio=bio->bi_next) {
1900 bio->bi_flags &= ~(BIO_POOL_MASK - 1);
1901 if (bio->bi_end_io)
1902 bio->bi_flags |= 1 << BIO_UPTODATE;
1903 bio->bi_vcnt = 0;
1904 bio->bi_idx = 0;
1905 bio->bi_phys_segments = 0;
1906 bio->bi_hw_segments = 0;
1907 bio->bi_size = 0;
1910 nr_sectors = 0;
1911 if (sector_nr + max_sync < max_sector)
1912 max_sector = sector_nr + max_sync;
1913 do {
1914 struct page *page;
1915 int len = PAGE_SIZE;
1916 disk = 0;
1917 if (sector_nr + (len>>9) > max_sector)
1918 len = (max_sector - sector_nr) << 9;
1919 if (len == 0)
1920 break;
1921 for (bio= biolist ; bio ; bio=bio->bi_next) {
1922 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1923 if (bio_add_page(bio, page, len, 0) == 0) {
1924 /* stop here */
1925 struct bio *bio2;
1926 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1927 for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) {
1928 /* remove last page from this bio */
1929 bio2->bi_vcnt--;
1930 bio2->bi_size -= len;
1931 bio2->bi_flags &= ~(1<< BIO_SEG_VALID);
1933 goto bio_full;
1935 disk = i;
1937 nr_sectors += len>>9;
1938 sector_nr += len>>9;
1939 } while (biolist->bi_vcnt < RESYNC_PAGES);
1940 bio_full:
1941 r10_bio->sectors = nr_sectors;
1943 while (biolist) {
1944 bio = biolist;
1945 biolist = biolist->bi_next;
1947 bio->bi_next = NULL;
1948 r10_bio = bio->bi_private;
1949 r10_bio->sectors = nr_sectors;
1951 if (bio->bi_end_io == end_sync_read) {
1952 md_sync_acct(bio->bi_bdev, nr_sectors);
1953 generic_make_request(bio);
1957 if (sectors_skipped)
1958 /* pretend they weren't skipped, it makes
1959 * no important difference in this case
1961 md_done_sync(mddev, sectors_skipped, 1);
1963 return sectors_skipped + nr_sectors;
1964 giveup:
1965 /* There is nowhere to write, so all non-sync
1966 * drives must be failed, so try the next chunk...
1969 sector_t sec = max_sector - sector_nr;
1970 sectors_skipped += sec;
1971 chunks_skipped ++;
1972 sector_nr = max_sector;
1973 goto skipped;
1977 static int run(mddev_t *mddev)
1979 conf_t *conf;
1980 int i, disk_idx;
1981 mirror_info_t *disk;
1982 mdk_rdev_t *rdev;
1983 struct list_head *tmp;
1984 int nc, fc, fo;
1985 sector_t stride, size;
1987 if (mddev->chunk_size == 0) {
1988 printk(KERN_ERR "md/raid10: non-zero chunk size required.\n");
1989 return -EINVAL;
1992 nc = mddev->layout & 255;
1993 fc = (mddev->layout >> 8) & 255;
1994 fo = mddev->layout & (1<<16);
1995 if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks ||
1996 (mddev->layout >> 17)) {
1997 printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n",
1998 mdname(mddev), mddev->layout);
1999 goto out;
2002 * copy the already verified devices into our private RAID10
2003 * bookkeeping area. [whatever we allocate in run(),
2004 * should be freed in stop()]
2006 conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
2007 mddev->private = conf;
2008 if (!conf) {
2009 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
2010 mdname(mddev));
2011 goto out;
2013 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
2014 GFP_KERNEL);
2015 if (!conf->mirrors) {
2016 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
2017 mdname(mddev));
2018 goto out_free_conf;
2021 conf->tmppage = alloc_page(GFP_KERNEL);
2022 if (!conf->tmppage)
2023 goto out_free_conf;
2025 conf->mddev = mddev;
2026 conf->raid_disks = mddev->raid_disks;
2027 conf->near_copies = nc;
2028 conf->far_copies = fc;
2029 conf->copies = nc*fc;
2030 conf->far_offset = fo;
2031 conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1;
2032 conf->chunk_shift = ffz(~mddev->chunk_size) - 9;
2033 size = mddev->size >> (conf->chunk_shift-1);
2034 sector_div(size, fc);
2035 size = size * conf->raid_disks;
2036 sector_div(size, nc);
2037 /* 'size' is now the number of chunks in the array */
2038 /* calculate "used chunks per device" in 'stride' */
2039 stride = size * conf->copies;
2040 sector_div(stride, conf->raid_disks);
2041 mddev->size = stride << (conf->chunk_shift-1);
2043 if (fo)
2044 stride = 1;
2045 else
2046 sector_div(stride, fc);
2047 conf->stride = stride << conf->chunk_shift;
2049 conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
2050 r10bio_pool_free, conf);
2051 if (!conf->r10bio_pool) {
2052 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
2053 mdname(mddev));
2054 goto out_free_conf;
2057 ITERATE_RDEV(mddev, rdev, tmp) {
2058 disk_idx = rdev->raid_disk;
2059 if (disk_idx >= mddev->raid_disks
2060 || disk_idx < 0)
2061 continue;
2062 disk = conf->mirrors + disk_idx;
2064 disk->rdev = rdev;
2066 blk_queue_stack_limits(mddev->queue,
2067 rdev->bdev->bd_disk->queue);
2068 /* as we don't honour merge_bvec_fn, we must never risk
2069 * violating it, so limit ->max_sector to one PAGE, as
2070 * a one page request is never in violation.
2072 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
2073 mddev->queue->max_sectors > (PAGE_SIZE>>9))
2074 mddev->queue->max_sectors = (PAGE_SIZE>>9);
2076 disk->head_position = 0;
2078 spin_lock_init(&conf->device_lock);
2079 INIT_LIST_HEAD(&conf->retry_list);
2081 spin_lock_init(&conf->resync_lock);
2082 init_waitqueue_head(&conf->wait_barrier);
2084 /* need to check that every block has at least one working mirror */
2085 if (!enough(conf)) {
2086 printk(KERN_ERR "raid10: not enough operational mirrors for %s\n",
2087 mdname(mddev));
2088 goto out_free_conf;
2091 mddev->degraded = 0;
2092 for (i = 0; i < conf->raid_disks; i++) {
2094 disk = conf->mirrors + i;
2096 if (!disk->rdev ||
2097 !test_bit(In_sync, &disk->rdev->flags)) {
2098 disk->head_position = 0;
2099 mddev->degraded++;
2104 mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10");
2105 if (!mddev->thread) {
2106 printk(KERN_ERR
2107 "raid10: couldn't allocate thread for %s\n",
2108 mdname(mddev));
2109 goto out_free_conf;
2112 printk(KERN_INFO
2113 "raid10: raid set %s active with %d out of %d devices\n",
2114 mdname(mddev), mddev->raid_disks - mddev->degraded,
2115 mddev->raid_disks);
2117 * Ok, everything is just fine now
2119 mddev->array_size = size << (conf->chunk_shift-1);
2120 mddev->resync_max_sectors = size << conf->chunk_shift;
2122 mddev->queue->unplug_fn = raid10_unplug;
2123 mddev->queue->issue_flush_fn = raid10_issue_flush;
2124 mddev->queue->backing_dev_info.congested_fn = raid10_congested;
2125 mddev->queue->backing_dev_info.congested_data = mddev;
2127 /* Calculate max read-ahead size.
2128 * We need to readahead at least twice a whole stripe....
2129 * maybe...
2132 int stripe = conf->raid_disks * (mddev->chunk_size / PAGE_SIZE);
2133 stripe /= conf->near_copies;
2134 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
2135 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
2138 if (conf->near_copies < mddev->raid_disks)
2139 blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
2140 return 0;
2142 out_free_conf:
2143 if (conf->r10bio_pool)
2144 mempool_destroy(conf->r10bio_pool);
2145 safe_put_page(conf->tmppage);
2146 kfree(conf->mirrors);
2147 kfree(conf);
2148 mddev->private = NULL;
2149 out:
2150 return -EIO;
2153 static int stop(mddev_t *mddev)
2155 conf_t *conf = mddev_to_conf(mddev);
2157 md_unregister_thread(mddev->thread);
2158 mddev->thread = NULL;
2159 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2160 if (conf->r10bio_pool)
2161 mempool_destroy(conf->r10bio_pool);
2162 kfree(conf->mirrors);
2163 kfree(conf);
2164 mddev->private = NULL;
2165 return 0;
2168 static void raid10_quiesce(mddev_t *mddev, int state)
2170 conf_t *conf = mddev_to_conf(mddev);
2172 switch(state) {
2173 case 1:
2174 raise_barrier(conf, 0);
2175 break;
2176 case 0:
2177 lower_barrier(conf);
2178 break;
2180 if (mddev->thread) {
2181 if (mddev->bitmap)
2182 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
2183 else
2184 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
2185 md_wakeup_thread(mddev->thread);
2189 static struct mdk_personality raid10_personality =
2191 .name = "raid10",
2192 .level = 10,
2193 .owner = THIS_MODULE,
2194 .make_request = make_request,
2195 .run = run,
2196 .stop = stop,
2197 .status = status,
2198 .error_handler = error,
2199 .hot_add_disk = raid10_add_disk,
2200 .hot_remove_disk= raid10_remove_disk,
2201 .spare_active = raid10_spare_active,
2202 .sync_request = sync_request,
2203 .quiesce = raid10_quiesce,
2206 static int __init raid_init(void)
2208 return register_md_personality(&raid10_personality);
2211 static void raid_exit(void)
2213 unregister_md_personality(&raid10_personality);
2216 module_init(raid_init);
2217 module_exit(raid_exit);
2218 MODULE_LICENSE("GPL");
2219 MODULE_ALIAS("md-personality-9"); /* RAID10 */
2220 MODULE_ALIAS("md-raid10");
2221 MODULE_ALIAS("md-level-10");