2 * raid5.c : Multiple Devices driver for Linux
3 * Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
4 * Copyright (C) 1999, 2000 Ingo Molnar
5 * Copyright (C) 2002, 2003 H. Peter Anvin
7 * RAID-4/5/6 management functions.
8 * Thanks to Penguin Computing for making the RAID-6 development possible
9 * by donating a test server!
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.
24 * The sequencing for updating the bitmap reliably is a little
25 * subtle (and I got it wrong the first time) so it deserves some
28 * We group bitmap updates into batches. Each batch has a number.
29 * We may write out several batches at once, but that isn't very important.
30 * conf->seq_write is the number of the last batch successfully written.
31 * conf->seq_flush is the number of the last batch that was closed to
33 * When we discover that we will need to write to any block in a stripe
34 * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
35 * the number of the batch it will be in. This is seq_flush+1.
36 * When we are ready to do a write, if that batch hasn't been written yet,
37 * we plug the array and queue the stripe for later.
38 * When an unplug happens, we increment bm_flush, thus closing the current
40 * When we notice that bm_flush > bm_write, we write out all pending updates
41 * to the bitmap, and advance bm_write to where bm_flush was.
42 * This may occasionally write a bit out twice, but is sure never to
46 #include <linux/blkdev.h>
47 #include <linux/kthread.h>
48 #include <linux/raid/pq.h>
49 #include <linux/async_tx.h>
50 #include <linux/async.h>
51 #include <linux/seq_file.h>
52 #include <linux/cpu.h>
53 #include <linux/slab.h>
54 #include <linux/ratelimit.h>
64 #define NR_STRIPES 256
65 #define STRIPE_SIZE PAGE_SIZE
66 #define STRIPE_SHIFT (PAGE_SHIFT - 9)
67 #define STRIPE_SECTORS (STRIPE_SIZE>>9)
68 #define IO_THRESHOLD 1
69 #define BYPASS_THRESHOLD 1
70 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
71 #define HASH_MASK (NR_HASH - 1)
73 #define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
75 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
76 * order without overlap. There may be several bio's per stripe+device, and
77 * a bio could span several devices.
78 * When walking this list for a particular stripe+device, we must never proceed
79 * beyond a bio that extends past this device, as the next bio might no longer
81 * This macro is used to determine the 'next' bio in the list, given the sector
82 * of the current stripe+device
84 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
86 * The following can be used to debug the driver
88 #define RAID5_PARANOIA 1
89 #if RAID5_PARANOIA && defined(CONFIG_SMP)
90 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
92 # define CHECK_DEVLOCK()
101 * We maintain a biased count of active stripes in the bottom 16 bits of
102 * bi_phys_segments, and a count of processed stripes in the upper 16 bits
104 static inline int raid5_bi_phys_segments(struct bio *bio)
106 return bio->bi_phys_segments & 0xffff;
109 static inline int raid5_bi_hw_segments(struct bio *bio)
111 return (bio->bi_phys_segments >> 16) & 0xffff;
114 static inline int raid5_dec_bi_phys_segments(struct bio *bio)
116 --bio->bi_phys_segments;
117 return raid5_bi_phys_segments(bio);
120 static inline int raid5_dec_bi_hw_segments(struct bio *bio)
122 unsigned short val = raid5_bi_hw_segments(bio);
125 bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio);
129 static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)
131 bio->bi_phys_segments = raid5_bi_phys_segments(bio) | (cnt << 16);
134 /* Find first data disk in a raid6 stripe */
135 static inline int raid6_d0(struct stripe_head *sh)
138 /* ddf always start from first device */
140 /* md starts just after Q block */
141 if (sh->qd_idx == sh->disks - 1)
144 return sh->qd_idx + 1;
146 static inline int raid6_next_disk(int disk, int raid_disks)
149 return (disk < raid_disks) ? disk : 0;
152 /* When walking through the disks in a raid5, starting at raid6_d0,
153 * We need to map each disk to a 'slot', where the data disks are slot
154 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
155 * is raid_disks-1. This help does that mapping.
157 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
158 int *count, int syndrome_disks)
164 if (idx == sh->pd_idx)
165 return syndrome_disks;
166 if (idx == sh->qd_idx)
167 return syndrome_disks + 1;
173 static void return_io(struct bio *return_bi)
175 struct bio *bi = return_bi;
178 return_bi = bi->bi_next;
186 static void print_raid5_conf (raid5_conf_t *conf);
188 static int stripe_operations_active(struct stripe_head *sh)
190 return sh->check_state || sh->reconstruct_state ||
191 test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
192 test_bit(STRIPE_COMPUTE_RUN, &sh->state);
195 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
197 if (atomic_dec_and_test(&sh->count)) {
198 BUG_ON(!list_empty(&sh->lru));
199 BUG_ON(atomic_read(&conf->active_stripes)==0);
200 if (test_bit(STRIPE_HANDLE, &sh->state)) {
201 if (test_bit(STRIPE_DELAYED, &sh->state))
202 list_add_tail(&sh->lru, &conf->delayed_list);
203 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
204 sh->bm_seq - conf->seq_write > 0)
205 list_add_tail(&sh->lru, &conf->bitmap_list);
207 clear_bit(STRIPE_BIT_DELAY, &sh->state);
208 list_add_tail(&sh->lru, &conf->handle_list);
210 md_wakeup_thread(conf->mddev->thread);
212 BUG_ON(stripe_operations_active(sh));
213 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
214 atomic_dec(&conf->preread_active_stripes);
215 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
216 md_wakeup_thread(conf->mddev->thread);
218 atomic_dec(&conf->active_stripes);
219 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
220 list_add_tail(&sh->lru, &conf->inactive_list);
221 wake_up(&conf->wait_for_stripe);
222 if (conf->retry_read_aligned)
223 md_wakeup_thread(conf->mddev->thread);
229 static void release_stripe(struct stripe_head *sh)
231 raid5_conf_t *conf = sh->raid_conf;
234 spin_lock_irqsave(&conf->device_lock, flags);
235 __release_stripe(conf, sh);
236 spin_unlock_irqrestore(&conf->device_lock, flags);
239 static inline void remove_hash(struct stripe_head *sh)
241 pr_debug("remove_hash(), stripe %llu\n",
242 (unsigned long long)sh->sector);
244 hlist_del_init(&sh->hash);
247 static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
249 struct hlist_head *hp = stripe_hash(conf, sh->sector);
251 pr_debug("insert_hash(), stripe %llu\n",
252 (unsigned long long)sh->sector);
255 hlist_add_head(&sh->hash, hp);
259 /* find an idle stripe, make sure it is unhashed, and return it. */
260 static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
262 struct stripe_head *sh = NULL;
263 struct list_head *first;
266 if (list_empty(&conf->inactive_list))
268 first = conf->inactive_list.next;
269 sh = list_entry(first, struct stripe_head, lru);
270 list_del_init(first);
272 atomic_inc(&conf->active_stripes);
277 static void shrink_buffers(struct stripe_head *sh)
281 int num = sh->raid_conf->pool_size;
283 for (i = 0; i < num ; i++) {
287 sh->dev[i].page = NULL;
292 static int grow_buffers(struct stripe_head *sh)
295 int num = sh->raid_conf->pool_size;
297 for (i = 0; i < num; i++) {
300 if (!(page = alloc_page(GFP_KERNEL))) {
303 sh->dev[i].page = page;
308 static void raid5_build_block(struct stripe_head *sh, int i, int previous);
309 static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
310 struct stripe_head *sh);
312 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
314 raid5_conf_t *conf = sh->raid_conf;
317 BUG_ON(atomic_read(&sh->count) != 0);
318 BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
319 BUG_ON(stripe_operations_active(sh));
322 pr_debug("init_stripe called, stripe %llu\n",
323 (unsigned long long)sh->sector);
327 sh->generation = conf->generation - previous;
328 sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
330 stripe_set_idx(sector, conf, previous, sh);
334 for (i = sh->disks; i--; ) {
335 struct r5dev *dev = &sh->dev[i];
337 if (dev->toread || dev->read || dev->towrite || dev->written ||
338 test_bit(R5_LOCKED, &dev->flags)) {
339 printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n",
340 (unsigned long long)sh->sector, i, dev->toread,
341 dev->read, dev->towrite, dev->written,
342 test_bit(R5_LOCKED, &dev->flags));
346 raid5_build_block(sh, i, previous);
348 insert_hash(conf, sh);
351 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector,
354 struct stripe_head *sh;
355 struct hlist_node *hn;
358 pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
359 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
360 if (sh->sector == sector && sh->generation == generation)
362 pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
367 * Need to check if array has failed when deciding whether to:
369 * - remove non-faulty devices
372 * This determination is simple when no reshape is happening.
373 * However if there is a reshape, we need to carefully check
374 * both the before and after sections.
375 * This is because some failed devices may only affect one
376 * of the two sections, and some non-in_sync devices may
377 * be insync in the section most affected by failed devices.
379 static int has_failed(raid5_conf_t *conf)
383 if (conf->mddev->reshape_position == MaxSector)
384 return conf->mddev->degraded > conf->max_degraded;
388 for (i = 0; i < conf->previous_raid_disks; i++) {
389 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
390 if (!rdev || test_bit(Faulty, &rdev->flags))
392 else if (test_bit(In_sync, &rdev->flags))
395 /* not in-sync or faulty.
396 * If the reshape increases the number of devices,
397 * this is being recovered by the reshape, so
398 * this 'previous' section is not in_sync.
399 * If the number of devices is being reduced however,
400 * the device can only be part of the array if
401 * we are reverting a reshape, so this section will
404 if (conf->raid_disks >= conf->previous_raid_disks)
408 if (degraded > conf->max_degraded)
412 for (i = 0; i < conf->raid_disks; i++) {
413 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
414 if (!rdev || test_bit(Faulty, &rdev->flags))
416 else if (test_bit(In_sync, &rdev->flags))
419 /* not in-sync or faulty.
420 * If reshape increases the number of devices, this
421 * section has already been recovered, else it
422 * almost certainly hasn't.
424 if (conf->raid_disks <= conf->previous_raid_disks)
428 if (degraded > conf->max_degraded)
433 static struct stripe_head *
434 get_active_stripe(raid5_conf_t *conf, sector_t sector,
435 int previous, int noblock, int noquiesce)
437 struct stripe_head *sh;
439 pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
441 spin_lock_irq(&conf->device_lock);
444 wait_event_lock_irq(conf->wait_for_stripe,
445 conf->quiesce == 0 || noquiesce,
446 conf->device_lock, /* nothing */);
447 sh = __find_stripe(conf, sector, conf->generation - previous);
449 if (!conf->inactive_blocked)
450 sh = get_free_stripe(conf);
451 if (noblock && sh == NULL)
454 conf->inactive_blocked = 1;
455 wait_event_lock_irq(conf->wait_for_stripe,
456 !list_empty(&conf->inactive_list) &&
457 (atomic_read(&conf->active_stripes)
458 < (conf->max_nr_stripes *3/4)
459 || !conf->inactive_blocked),
462 conf->inactive_blocked = 0;
464 init_stripe(sh, sector, previous);
466 if (atomic_read(&sh->count)) {
467 BUG_ON(!list_empty(&sh->lru)
468 && !test_bit(STRIPE_EXPANDING, &sh->state));
470 if (!test_bit(STRIPE_HANDLE, &sh->state))
471 atomic_inc(&conf->active_stripes);
472 if (list_empty(&sh->lru) &&
473 !test_bit(STRIPE_EXPANDING, &sh->state))
475 list_del_init(&sh->lru);
478 } while (sh == NULL);
481 atomic_inc(&sh->count);
483 spin_unlock_irq(&conf->device_lock);
488 raid5_end_read_request(struct bio *bi, int error);
490 raid5_end_write_request(struct bio *bi, int error);
492 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
494 raid5_conf_t *conf = sh->raid_conf;
495 int i, disks = sh->disks;
499 for (i = disks; i--; ) {
503 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
504 if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
508 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
513 bi = &sh->dev[i].req;
517 bi->bi_end_io = raid5_end_write_request;
519 bi->bi_end_io = raid5_end_read_request;
522 rdev = rcu_dereference(conf->disks[i].rdev);
523 if (rdev && test_bit(Faulty, &rdev->flags))
526 atomic_inc(&rdev->nr_pending);
530 if (s->syncing || s->expanding || s->expanded)
531 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
533 set_bit(STRIPE_IO_STARTED, &sh->state);
535 bi->bi_bdev = rdev->bdev;
536 pr_debug("%s: for %llu schedule op %ld on disc %d\n",
537 __func__, (unsigned long long)sh->sector,
539 atomic_inc(&sh->count);
540 bi->bi_sector = sh->sector + rdev->data_offset;
541 bi->bi_flags = 1 << BIO_UPTODATE;
545 bi->bi_io_vec = &sh->dev[i].vec;
546 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
547 bi->bi_io_vec[0].bv_offset = 0;
548 bi->bi_size = STRIPE_SIZE;
550 generic_make_request(bi);
553 set_bit(STRIPE_DEGRADED, &sh->state);
554 pr_debug("skip op %ld on disc %d for sector %llu\n",
555 bi->bi_rw, i, (unsigned long long)sh->sector);
556 clear_bit(R5_LOCKED, &sh->dev[i].flags);
557 set_bit(STRIPE_HANDLE, &sh->state);
562 static struct dma_async_tx_descriptor *
563 async_copy_data(int frombio, struct bio *bio, struct page *page,
564 sector_t sector, struct dma_async_tx_descriptor *tx)
567 struct page *bio_page;
570 struct async_submit_ctl submit;
571 enum async_tx_flags flags = 0;
573 if (bio->bi_sector >= sector)
574 page_offset = (signed)(bio->bi_sector - sector) * 512;
576 page_offset = (signed)(sector - bio->bi_sector) * -512;
579 flags |= ASYNC_TX_FENCE;
580 init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
582 bio_for_each_segment(bvl, bio, i) {
583 int len = bvl->bv_len;
587 if (page_offset < 0) {
588 b_offset = -page_offset;
589 page_offset += b_offset;
593 if (len > 0 && page_offset + len > STRIPE_SIZE)
594 clen = STRIPE_SIZE - page_offset;
599 b_offset += bvl->bv_offset;
600 bio_page = bvl->bv_page;
602 tx = async_memcpy(page, bio_page, page_offset,
603 b_offset, clen, &submit);
605 tx = async_memcpy(bio_page, page, b_offset,
606 page_offset, clen, &submit);
608 /* chain the operations */
609 submit.depend_tx = tx;
611 if (clen < len) /* hit end of page */
619 static void ops_complete_biofill(void *stripe_head_ref)
621 struct stripe_head *sh = stripe_head_ref;
622 struct bio *return_bi = NULL;
623 raid5_conf_t *conf = sh->raid_conf;
626 pr_debug("%s: stripe %llu\n", __func__,
627 (unsigned long long)sh->sector);
629 /* clear completed biofills */
630 spin_lock_irq(&conf->device_lock);
631 for (i = sh->disks; i--; ) {
632 struct r5dev *dev = &sh->dev[i];
634 /* acknowledge completion of a biofill operation */
635 /* and check if we need to reply to a read request,
636 * new R5_Wantfill requests are held off until
637 * !STRIPE_BIOFILL_RUN
639 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
640 struct bio *rbi, *rbi2;
645 while (rbi && rbi->bi_sector <
646 dev->sector + STRIPE_SECTORS) {
647 rbi2 = r5_next_bio(rbi, dev->sector);
648 if (!raid5_dec_bi_phys_segments(rbi)) {
649 rbi->bi_next = return_bi;
656 spin_unlock_irq(&conf->device_lock);
657 clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
659 return_io(return_bi);
661 set_bit(STRIPE_HANDLE, &sh->state);
665 static void ops_run_biofill(struct stripe_head *sh)
667 struct dma_async_tx_descriptor *tx = NULL;
668 raid5_conf_t *conf = sh->raid_conf;
669 struct async_submit_ctl submit;
672 pr_debug("%s: stripe %llu\n", __func__,
673 (unsigned long long)sh->sector);
675 for (i = sh->disks; i--; ) {
676 struct r5dev *dev = &sh->dev[i];
677 if (test_bit(R5_Wantfill, &dev->flags)) {
679 spin_lock_irq(&conf->device_lock);
680 dev->read = rbi = dev->toread;
682 spin_unlock_irq(&conf->device_lock);
683 while (rbi && rbi->bi_sector <
684 dev->sector + STRIPE_SECTORS) {
685 tx = async_copy_data(0, rbi, dev->page,
687 rbi = r5_next_bio(rbi, dev->sector);
692 atomic_inc(&sh->count);
693 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
694 async_trigger_callback(&submit);
697 static void mark_target_uptodate(struct stripe_head *sh, int target)
704 tgt = &sh->dev[target];
705 set_bit(R5_UPTODATE, &tgt->flags);
706 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
707 clear_bit(R5_Wantcompute, &tgt->flags);
710 static void ops_complete_compute(void *stripe_head_ref)
712 struct stripe_head *sh = stripe_head_ref;
714 pr_debug("%s: stripe %llu\n", __func__,
715 (unsigned long long)sh->sector);
717 /* mark the computed target(s) as uptodate */
718 mark_target_uptodate(sh, sh->ops.target);
719 mark_target_uptodate(sh, sh->ops.target2);
721 clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
722 if (sh->check_state == check_state_compute_run)
723 sh->check_state = check_state_compute_result;
724 set_bit(STRIPE_HANDLE, &sh->state);
728 /* return a pointer to the address conversion region of the scribble buffer */
729 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
730 struct raid5_percpu *percpu)
732 return percpu->scribble + sizeof(struct page *) * (sh->disks + 2);
735 static struct dma_async_tx_descriptor *
736 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
738 int disks = sh->disks;
739 struct page **xor_srcs = percpu->scribble;
740 int target = sh->ops.target;
741 struct r5dev *tgt = &sh->dev[target];
742 struct page *xor_dest = tgt->page;
744 struct dma_async_tx_descriptor *tx;
745 struct async_submit_ctl submit;
748 pr_debug("%s: stripe %llu block: %d\n",
749 __func__, (unsigned long long)sh->sector, target);
750 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
752 for (i = disks; i--; )
754 xor_srcs[count++] = sh->dev[i].page;
756 atomic_inc(&sh->count);
758 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
759 ops_complete_compute, sh, to_addr_conv(sh, percpu));
760 if (unlikely(count == 1))
761 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
763 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
768 /* set_syndrome_sources - populate source buffers for gen_syndrome
769 * @srcs - (struct page *) array of size sh->disks
770 * @sh - stripe_head to parse
772 * Populates srcs in proper layout order for the stripe and returns the
773 * 'count' of sources to be used in a call to async_gen_syndrome. The P
774 * destination buffer is recorded in srcs[count] and the Q destination
775 * is recorded in srcs[count+1]].
777 static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
779 int disks = sh->disks;
780 int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
781 int d0_idx = raid6_d0(sh);
785 for (i = 0; i < disks; i++)
791 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
793 srcs[slot] = sh->dev[i].page;
794 i = raid6_next_disk(i, disks);
795 } while (i != d0_idx);
797 return syndrome_disks;
800 static struct dma_async_tx_descriptor *
801 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
803 int disks = sh->disks;
804 struct page **blocks = percpu->scribble;
806 int qd_idx = sh->qd_idx;
807 struct dma_async_tx_descriptor *tx;
808 struct async_submit_ctl submit;
814 if (sh->ops.target < 0)
815 target = sh->ops.target2;
816 else if (sh->ops.target2 < 0)
817 target = sh->ops.target;
819 /* we should only have one valid target */
822 pr_debug("%s: stripe %llu block: %d\n",
823 __func__, (unsigned long long)sh->sector, target);
825 tgt = &sh->dev[target];
826 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
829 atomic_inc(&sh->count);
831 if (target == qd_idx) {
832 count = set_syndrome_sources(blocks, sh);
833 blocks[count] = NULL; /* regenerating p is not necessary */
834 BUG_ON(blocks[count+1] != dest); /* q should already be set */
835 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
836 ops_complete_compute, sh,
837 to_addr_conv(sh, percpu));
838 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
840 /* Compute any data- or p-drive using XOR */
842 for (i = disks; i-- ; ) {
843 if (i == target || i == qd_idx)
845 blocks[count++] = sh->dev[i].page;
848 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
849 NULL, ops_complete_compute, sh,
850 to_addr_conv(sh, percpu));
851 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
857 static struct dma_async_tx_descriptor *
858 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
860 int i, count, disks = sh->disks;
861 int syndrome_disks = sh->ddf_layout ? disks : disks-2;
862 int d0_idx = raid6_d0(sh);
863 int faila = -1, failb = -1;
864 int target = sh->ops.target;
865 int target2 = sh->ops.target2;
866 struct r5dev *tgt = &sh->dev[target];
867 struct r5dev *tgt2 = &sh->dev[target2];
868 struct dma_async_tx_descriptor *tx;
869 struct page **blocks = percpu->scribble;
870 struct async_submit_ctl submit;
872 pr_debug("%s: stripe %llu block1: %d block2: %d\n",
873 __func__, (unsigned long long)sh->sector, target, target2);
874 BUG_ON(target < 0 || target2 < 0);
875 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
876 BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
878 /* we need to open-code set_syndrome_sources to handle the
879 * slot number conversion for 'faila' and 'failb'
881 for (i = 0; i < disks ; i++)
886 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
888 blocks[slot] = sh->dev[i].page;
894 i = raid6_next_disk(i, disks);
895 } while (i != d0_idx);
897 BUG_ON(faila == failb);
900 pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
901 __func__, (unsigned long long)sh->sector, faila, failb);
903 atomic_inc(&sh->count);
905 if (failb == syndrome_disks+1) {
906 /* Q disk is one of the missing disks */
907 if (faila == syndrome_disks) {
908 /* Missing P+Q, just recompute */
909 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
910 ops_complete_compute, sh,
911 to_addr_conv(sh, percpu));
912 return async_gen_syndrome(blocks, 0, syndrome_disks+2,
913 STRIPE_SIZE, &submit);
917 int qd_idx = sh->qd_idx;
919 /* Missing D+Q: recompute D from P, then recompute Q */
920 if (target == qd_idx)
921 data_target = target2;
923 data_target = target;
926 for (i = disks; i-- ; ) {
927 if (i == data_target || i == qd_idx)
929 blocks[count++] = sh->dev[i].page;
931 dest = sh->dev[data_target].page;
932 init_async_submit(&submit,
933 ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
935 to_addr_conv(sh, percpu));
936 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
939 count = set_syndrome_sources(blocks, sh);
940 init_async_submit(&submit, ASYNC_TX_FENCE, tx,
941 ops_complete_compute, sh,
942 to_addr_conv(sh, percpu));
943 return async_gen_syndrome(blocks, 0, count+2,
944 STRIPE_SIZE, &submit);
947 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
948 ops_complete_compute, sh,
949 to_addr_conv(sh, percpu));
950 if (failb == syndrome_disks) {
951 /* We're missing D+P. */
952 return async_raid6_datap_recov(syndrome_disks+2,
956 /* We're missing D+D. */
957 return async_raid6_2data_recov(syndrome_disks+2,
958 STRIPE_SIZE, faila, failb,
965 static void ops_complete_prexor(void *stripe_head_ref)
967 struct stripe_head *sh = stripe_head_ref;
969 pr_debug("%s: stripe %llu\n", __func__,
970 (unsigned long long)sh->sector);
973 static struct dma_async_tx_descriptor *
974 ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
975 struct dma_async_tx_descriptor *tx)
977 int disks = sh->disks;
978 struct page **xor_srcs = percpu->scribble;
979 int count = 0, pd_idx = sh->pd_idx, i;
980 struct async_submit_ctl submit;
982 /* existing parity data subtracted */
983 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
985 pr_debug("%s: stripe %llu\n", __func__,
986 (unsigned long long)sh->sector);
988 for (i = disks; i--; ) {
989 struct r5dev *dev = &sh->dev[i];
990 /* Only process blocks that are known to be uptodate */
991 if (test_bit(R5_Wantdrain, &dev->flags))
992 xor_srcs[count++] = dev->page;
995 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
996 ops_complete_prexor, sh, to_addr_conv(sh, percpu));
997 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1002 static struct dma_async_tx_descriptor *
1003 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1005 int disks = sh->disks;
1008 pr_debug("%s: stripe %llu\n", __func__,
1009 (unsigned long long)sh->sector);
1011 for (i = disks; i--; ) {
1012 struct r5dev *dev = &sh->dev[i];
1015 if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
1018 spin_lock_irq(&sh->raid_conf->device_lock);
1019 chosen = dev->towrite;
1020 dev->towrite = NULL;
1021 BUG_ON(dev->written);
1022 wbi = dev->written = chosen;
1023 spin_unlock_irq(&sh->raid_conf->device_lock);
1025 while (wbi && wbi->bi_sector <
1026 dev->sector + STRIPE_SECTORS) {
1027 if (wbi->bi_rw & REQ_FUA)
1028 set_bit(R5_WantFUA, &dev->flags);
1029 tx = async_copy_data(1, wbi, dev->page,
1031 wbi = r5_next_bio(wbi, dev->sector);
1039 static void ops_complete_reconstruct(void *stripe_head_ref)
1041 struct stripe_head *sh = stripe_head_ref;
1042 int disks = sh->disks;
1043 int pd_idx = sh->pd_idx;
1044 int qd_idx = sh->qd_idx;
1048 pr_debug("%s: stripe %llu\n", __func__,
1049 (unsigned long long)sh->sector);
1051 for (i = disks; i--; )
1052 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1054 for (i = disks; i--; ) {
1055 struct r5dev *dev = &sh->dev[i];
1057 if (dev->written || i == pd_idx || i == qd_idx) {
1058 set_bit(R5_UPTODATE, &dev->flags);
1060 set_bit(R5_WantFUA, &dev->flags);
1064 if (sh->reconstruct_state == reconstruct_state_drain_run)
1065 sh->reconstruct_state = reconstruct_state_drain_result;
1066 else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1067 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1069 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1070 sh->reconstruct_state = reconstruct_state_result;
1073 set_bit(STRIPE_HANDLE, &sh->state);
1078 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1079 struct dma_async_tx_descriptor *tx)
1081 int disks = sh->disks;
1082 struct page **xor_srcs = percpu->scribble;
1083 struct async_submit_ctl submit;
1084 int count = 0, pd_idx = sh->pd_idx, i;
1085 struct page *xor_dest;
1087 unsigned long flags;
1089 pr_debug("%s: stripe %llu\n", __func__,
1090 (unsigned long long)sh->sector);
1092 /* check if prexor is active which means only process blocks
1093 * that are part of a read-modify-write (written)
1095 if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1097 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1098 for (i = disks; i--; ) {
1099 struct r5dev *dev = &sh->dev[i];
1101 xor_srcs[count++] = dev->page;
1104 xor_dest = sh->dev[pd_idx].page;
1105 for (i = disks; i--; ) {
1106 struct r5dev *dev = &sh->dev[i];
1108 xor_srcs[count++] = dev->page;
1112 /* 1/ if we prexor'd then the dest is reused as a source
1113 * 2/ if we did not prexor then we are redoing the parity
1114 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1115 * for the synchronous xor case
1117 flags = ASYNC_TX_ACK |
1118 (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1120 atomic_inc(&sh->count);
1122 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
1123 to_addr_conv(sh, percpu));
1124 if (unlikely(count == 1))
1125 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1127 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1131 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1132 struct dma_async_tx_descriptor *tx)
1134 struct async_submit_ctl submit;
1135 struct page **blocks = percpu->scribble;
1138 pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1140 count = set_syndrome_sources(blocks, sh);
1142 atomic_inc(&sh->count);
1144 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct,
1145 sh, to_addr_conv(sh, percpu));
1146 async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1149 static void ops_complete_check(void *stripe_head_ref)
1151 struct stripe_head *sh = stripe_head_ref;
1153 pr_debug("%s: stripe %llu\n", __func__,
1154 (unsigned long long)sh->sector);
1156 sh->check_state = check_state_check_result;
1157 set_bit(STRIPE_HANDLE, &sh->state);
1161 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1163 int disks = sh->disks;
1164 int pd_idx = sh->pd_idx;
1165 int qd_idx = sh->qd_idx;
1166 struct page *xor_dest;
1167 struct page **xor_srcs = percpu->scribble;
1168 struct dma_async_tx_descriptor *tx;
1169 struct async_submit_ctl submit;
1173 pr_debug("%s: stripe %llu\n", __func__,
1174 (unsigned long long)sh->sector);
1177 xor_dest = sh->dev[pd_idx].page;
1178 xor_srcs[count++] = xor_dest;
1179 for (i = disks; i--; ) {
1180 if (i == pd_idx || i == qd_idx)
1182 xor_srcs[count++] = sh->dev[i].page;
1185 init_async_submit(&submit, 0, NULL, NULL, NULL,
1186 to_addr_conv(sh, percpu));
1187 tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
1188 &sh->ops.zero_sum_result, &submit);
1190 atomic_inc(&sh->count);
1191 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
1192 tx = async_trigger_callback(&submit);
1195 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
1197 struct page **srcs = percpu->scribble;
1198 struct async_submit_ctl submit;
1201 pr_debug("%s: stripe %llu checkp: %d\n", __func__,
1202 (unsigned long long)sh->sector, checkp);
1204 count = set_syndrome_sources(srcs, sh);
1208 atomic_inc(&sh->count);
1209 init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
1210 sh, to_addr_conv(sh, percpu));
1211 async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
1212 &sh->ops.zero_sum_result, percpu->spare_page, &submit);
1215 static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1217 int overlap_clear = 0, i, disks = sh->disks;
1218 struct dma_async_tx_descriptor *tx = NULL;
1219 raid5_conf_t *conf = sh->raid_conf;
1220 int level = conf->level;
1221 struct raid5_percpu *percpu;
1225 percpu = per_cpu_ptr(conf->percpu, cpu);
1226 if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
1227 ops_run_biofill(sh);
1231 if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
1233 tx = ops_run_compute5(sh, percpu);
1235 if (sh->ops.target2 < 0 || sh->ops.target < 0)
1236 tx = ops_run_compute6_1(sh, percpu);
1238 tx = ops_run_compute6_2(sh, percpu);
1240 /* terminate the chain if reconstruct is not set to be run */
1241 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
1245 if (test_bit(STRIPE_OP_PREXOR, &ops_request))
1246 tx = ops_run_prexor(sh, percpu, tx);
1248 if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
1249 tx = ops_run_biodrain(sh, tx);
1253 if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
1255 ops_run_reconstruct5(sh, percpu, tx);
1257 ops_run_reconstruct6(sh, percpu, tx);
1260 if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
1261 if (sh->check_state == check_state_run)
1262 ops_run_check_p(sh, percpu);
1263 else if (sh->check_state == check_state_run_q)
1264 ops_run_check_pq(sh, percpu, 0);
1265 else if (sh->check_state == check_state_run_pq)
1266 ops_run_check_pq(sh, percpu, 1);
1272 for (i = disks; i--; ) {
1273 struct r5dev *dev = &sh->dev[i];
1274 if (test_and_clear_bit(R5_Overlap, &dev->flags))
1275 wake_up(&sh->raid_conf->wait_for_overlap);
1280 #ifdef CONFIG_MULTICORE_RAID456
1281 static void async_run_ops(void *param, async_cookie_t cookie)
1283 struct stripe_head *sh = param;
1284 unsigned long ops_request = sh->ops.request;
1286 clear_bit_unlock(STRIPE_OPS_REQ_PENDING, &sh->state);
1287 wake_up(&sh->ops.wait_for_ops);
1289 __raid_run_ops(sh, ops_request);
1293 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1295 /* since handle_stripe can be called outside of raid5d context
1296 * we need to ensure sh->ops.request is de-staged before another
1299 wait_event(sh->ops.wait_for_ops,
1300 !test_and_set_bit_lock(STRIPE_OPS_REQ_PENDING, &sh->state));
1301 sh->ops.request = ops_request;
1303 atomic_inc(&sh->count);
1304 async_schedule(async_run_ops, sh);
1307 #define raid_run_ops __raid_run_ops
1310 static int grow_one_stripe(raid5_conf_t *conf)
1312 struct stripe_head *sh;
1313 sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL);
1317 sh->raid_conf = conf;
1318 #ifdef CONFIG_MULTICORE_RAID456
1319 init_waitqueue_head(&sh->ops.wait_for_ops);
1322 if (grow_buffers(sh)) {
1324 kmem_cache_free(conf->slab_cache, sh);
1327 /* we just created an active stripe so... */
1328 atomic_set(&sh->count, 1);
1329 atomic_inc(&conf->active_stripes);
1330 INIT_LIST_HEAD(&sh->lru);
1335 static int grow_stripes(raid5_conf_t *conf, int num)
1337 struct kmem_cache *sc;
1338 int devs = max(conf->raid_disks, conf->previous_raid_disks);
1340 if (conf->mddev->gendisk)
1341 sprintf(conf->cache_name[0],
1342 "raid%d-%s", conf->level, mdname(conf->mddev));
1344 sprintf(conf->cache_name[0],
1345 "raid%d-%p", conf->level, conf->mddev);
1346 sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
1348 conf->active_name = 0;
1349 sc = kmem_cache_create(conf->cache_name[conf->active_name],
1350 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
1354 conf->slab_cache = sc;
1355 conf->pool_size = devs;
1357 if (!grow_one_stripe(conf))
1363 * scribble_len - return the required size of the scribble region
1364 * @num - total number of disks in the array
1366 * The size must be enough to contain:
1367 * 1/ a struct page pointer for each device in the array +2
1368 * 2/ room to convert each entry in (1) to its corresponding dma
1369 * (dma_map_page()) or page (page_address()) address.
1371 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
1372 * calculate over all devices (not just the data blocks), using zeros in place
1373 * of the P and Q blocks.
1375 static size_t scribble_len(int num)
1379 len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
1384 static int resize_stripes(raid5_conf_t *conf, int newsize)
1386 /* Make all the stripes able to hold 'newsize' devices.
1387 * New slots in each stripe get 'page' set to a new page.
1389 * This happens in stages:
1390 * 1/ create a new kmem_cache and allocate the required number of
1392 * 2/ gather all the old stripe_heads and tranfer the pages across
1393 * to the new stripe_heads. This will have the side effect of
1394 * freezing the array as once all stripe_heads have been collected,
1395 * no IO will be possible. Old stripe heads are freed once their
1396 * pages have been transferred over, and the old kmem_cache is
1397 * freed when all stripes are done.
1398 * 3/ reallocate conf->disks to be suitable bigger. If this fails,
1399 * we simple return a failre status - no need to clean anything up.
1400 * 4/ allocate new pages for the new slots in the new stripe_heads.
1401 * If this fails, we don't bother trying the shrink the
1402 * stripe_heads down again, we just leave them as they are.
1403 * As each stripe_head is processed the new one is released into
1406 * Once step2 is started, we cannot afford to wait for a write,
1407 * so we use GFP_NOIO allocations.
1409 struct stripe_head *osh, *nsh;
1410 LIST_HEAD(newstripes);
1411 struct disk_info *ndisks;
1414 struct kmem_cache *sc;
1417 if (newsize <= conf->pool_size)
1418 return 0; /* never bother to shrink */
1420 err = md_allow_write(conf->mddev);
1425 sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
1426 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1431 for (i = conf->max_nr_stripes; i; i--) {
1432 nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
1436 nsh->raid_conf = conf;
1437 #ifdef CONFIG_MULTICORE_RAID456
1438 init_waitqueue_head(&nsh->ops.wait_for_ops);
1441 list_add(&nsh->lru, &newstripes);
1444 /* didn't get enough, give up */
1445 while (!list_empty(&newstripes)) {
1446 nsh = list_entry(newstripes.next, struct stripe_head, lru);
1447 list_del(&nsh->lru);
1448 kmem_cache_free(sc, nsh);
1450 kmem_cache_destroy(sc);
1453 /* Step 2 - Must use GFP_NOIO now.
1454 * OK, we have enough stripes, start collecting inactive
1455 * stripes and copying them over
1457 list_for_each_entry(nsh, &newstripes, lru) {
1458 spin_lock_irq(&conf->device_lock);
1459 wait_event_lock_irq(conf->wait_for_stripe,
1460 !list_empty(&conf->inactive_list),
1463 osh = get_free_stripe(conf);
1464 spin_unlock_irq(&conf->device_lock);
1465 atomic_set(&nsh->count, 1);
1466 for(i=0; i<conf->pool_size; i++)
1467 nsh->dev[i].page = osh->dev[i].page;
1468 for( ; i<newsize; i++)
1469 nsh->dev[i].page = NULL;
1470 kmem_cache_free(conf->slab_cache, osh);
1472 kmem_cache_destroy(conf->slab_cache);
1475 * At this point, we are holding all the stripes so the array
1476 * is completely stalled, so now is a good time to resize
1477 * conf->disks and the scribble region
1479 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
1481 for (i=0; i<conf->raid_disks; i++)
1482 ndisks[i] = conf->disks[i];
1484 conf->disks = ndisks;
1489 conf->scribble_len = scribble_len(newsize);
1490 for_each_present_cpu(cpu) {
1491 struct raid5_percpu *percpu;
1494 percpu = per_cpu_ptr(conf->percpu, cpu);
1495 scribble = kmalloc(conf->scribble_len, GFP_NOIO);
1498 kfree(percpu->scribble);
1499 percpu->scribble = scribble;
1507 /* Step 4, return new stripes to service */
1508 while(!list_empty(&newstripes)) {
1509 nsh = list_entry(newstripes.next, struct stripe_head, lru);
1510 list_del_init(&nsh->lru);
1512 for (i=conf->raid_disks; i < newsize; i++)
1513 if (nsh->dev[i].page == NULL) {
1514 struct page *p = alloc_page(GFP_NOIO);
1515 nsh->dev[i].page = p;
1519 release_stripe(nsh);
1521 /* critical section pass, GFP_NOIO no longer needed */
1523 conf->slab_cache = sc;
1524 conf->active_name = 1-conf->active_name;
1525 conf->pool_size = newsize;
1529 static int drop_one_stripe(raid5_conf_t *conf)
1531 struct stripe_head *sh;
1533 spin_lock_irq(&conf->device_lock);
1534 sh = get_free_stripe(conf);
1535 spin_unlock_irq(&conf->device_lock);
1538 BUG_ON(atomic_read(&sh->count));
1540 kmem_cache_free(conf->slab_cache, sh);
1541 atomic_dec(&conf->active_stripes);
1545 static void shrink_stripes(raid5_conf_t *conf)
1547 while (drop_one_stripe(conf))
1550 if (conf->slab_cache)
1551 kmem_cache_destroy(conf->slab_cache);
1552 conf->slab_cache = NULL;
1555 static void raid5_end_read_request(struct bio * bi, int error)
1557 struct stripe_head *sh = bi->bi_private;
1558 raid5_conf_t *conf = sh->raid_conf;
1559 int disks = sh->disks, i;
1560 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1561 char b[BDEVNAME_SIZE];
1565 for (i=0 ; i<disks; i++)
1566 if (bi == &sh->dev[i].req)
1569 pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
1570 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
1578 set_bit(R5_UPTODATE, &sh->dev[i].flags);
1579 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1580 rdev = conf->disks[i].rdev;
1583 "md/raid:%s: read error corrected"
1584 " (%lu sectors at %llu on %s)\n",
1585 mdname(conf->mddev), STRIPE_SECTORS,
1586 (unsigned long long)(sh->sector
1587 + rdev->data_offset),
1588 bdevname(rdev->bdev, b));
1589 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1590 clear_bit(R5_ReadError, &sh->dev[i].flags);
1591 clear_bit(R5_ReWrite, &sh->dev[i].flags);
1593 if (atomic_read(&conf->disks[i].rdev->read_errors))
1594 atomic_set(&conf->disks[i].rdev->read_errors, 0);
1596 const char *bdn = bdevname(conf->disks[i].rdev->bdev, b);
1598 rdev = conf->disks[i].rdev;
1600 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1601 atomic_inc(&rdev->read_errors);
1602 if (conf->mddev->degraded >= conf->max_degraded)
1605 "md/raid:%s: read error not correctable "
1606 "(sector %llu on %s).\n",
1607 mdname(conf->mddev),
1608 (unsigned long long)(sh->sector
1609 + rdev->data_offset),
1611 else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
1615 "md/raid:%s: read error NOT corrected!! "
1616 "(sector %llu on %s).\n",
1617 mdname(conf->mddev),
1618 (unsigned long long)(sh->sector
1619 + rdev->data_offset),
1621 else if (atomic_read(&rdev->read_errors)
1622 > conf->max_nr_stripes)
1624 "md/raid:%s: Too many read errors, failing device %s.\n",
1625 mdname(conf->mddev), bdn);
1629 set_bit(R5_ReadError, &sh->dev[i].flags);
1631 clear_bit(R5_ReadError, &sh->dev[i].flags);
1632 clear_bit(R5_ReWrite, &sh->dev[i].flags);
1633 md_error(conf->mddev, rdev);
1636 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
1637 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1638 set_bit(STRIPE_HANDLE, &sh->state);
1642 static void raid5_end_write_request(struct bio *bi, int error)
1644 struct stripe_head *sh = bi->bi_private;
1645 raid5_conf_t *conf = sh->raid_conf;
1646 int disks = sh->disks, i;
1647 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1649 for (i=0 ; i<disks; i++)
1650 if (bi == &sh->dev[i].req)
1653 pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
1654 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
1662 md_error(conf->mddev, conf->disks[i].rdev);
1664 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
1666 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1667 set_bit(STRIPE_HANDLE, &sh->state);
1672 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
1674 static void raid5_build_block(struct stripe_head *sh, int i, int previous)
1676 struct r5dev *dev = &sh->dev[i];
1678 bio_init(&dev->req);
1679 dev->req.bi_io_vec = &dev->vec;
1681 dev->req.bi_max_vecs++;
1682 dev->vec.bv_page = dev->page;
1683 dev->vec.bv_len = STRIPE_SIZE;
1684 dev->vec.bv_offset = 0;
1686 dev->req.bi_sector = sh->sector;
1687 dev->req.bi_private = sh;
1690 dev->sector = compute_blocknr(sh, i, previous);
1693 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1695 char b[BDEVNAME_SIZE];
1696 raid5_conf_t *conf = mddev->private;
1697 pr_debug("raid456: error called\n");
1699 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1700 unsigned long flags;
1701 spin_lock_irqsave(&conf->device_lock, flags);
1703 spin_unlock_irqrestore(&conf->device_lock, flags);
1705 * if recovery was running, make sure it aborts.
1707 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1709 set_bit(Blocked, &rdev->flags);
1710 set_bit(Faulty, &rdev->flags);
1711 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1713 "md/raid:%s: Disk failure on %s, disabling device.\n"
1714 "md/raid:%s: Operation continuing on %d devices.\n",
1716 bdevname(rdev->bdev, b),
1718 conf->raid_disks - mddev->degraded);
1722 * Input: a 'big' sector number,
1723 * Output: index of the data and parity disk, and the sector # in them.
1725 static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector,
1726 int previous, int *dd_idx,
1727 struct stripe_head *sh)
1729 sector_t stripe, stripe2;
1730 sector_t chunk_number;
1731 unsigned int chunk_offset;
1734 sector_t new_sector;
1735 int algorithm = previous ? conf->prev_algo
1737 int sectors_per_chunk = previous ? conf->prev_chunk_sectors
1738 : conf->chunk_sectors;
1739 int raid_disks = previous ? conf->previous_raid_disks
1741 int data_disks = raid_disks - conf->max_degraded;
1743 /* First compute the information on this sector */
1746 * Compute the chunk number and the sector offset inside the chunk
1748 chunk_offset = sector_div(r_sector, sectors_per_chunk);
1749 chunk_number = r_sector;
1752 * Compute the stripe number
1754 stripe = chunk_number;
1755 *dd_idx = sector_div(stripe, data_disks);
1758 * Select the parity disk based on the user selected algorithm.
1760 pd_idx = qd_idx = -1;
1761 switch(conf->level) {
1763 pd_idx = data_disks;
1766 switch (algorithm) {
1767 case ALGORITHM_LEFT_ASYMMETRIC:
1768 pd_idx = data_disks - sector_div(stripe2, raid_disks);
1769 if (*dd_idx >= pd_idx)
1772 case ALGORITHM_RIGHT_ASYMMETRIC:
1773 pd_idx = sector_div(stripe2, raid_disks);
1774 if (*dd_idx >= pd_idx)
1777 case ALGORITHM_LEFT_SYMMETRIC:
1778 pd_idx = data_disks - sector_div(stripe2, raid_disks);
1779 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
1781 case ALGORITHM_RIGHT_SYMMETRIC:
1782 pd_idx = sector_div(stripe2, raid_disks);
1783 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
1785 case ALGORITHM_PARITY_0:
1789 case ALGORITHM_PARITY_N:
1790 pd_idx = data_disks;
1798 switch (algorithm) {
1799 case ALGORITHM_LEFT_ASYMMETRIC:
1800 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
1801 qd_idx = pd_idx + 1;
1802 if (pd_idx == raid_disks-1) {
1803 (*dd_idx)++; /* Q D D D P */
1805 } else if (*dd_idx >= pd_idx)
1806 (*dd_idx) += 2; /* D D P Q D */
1808 case ALGORITHM_RIGHT_ASYMMETRIC:
1809 pd_idx = sector_div(stripe2, raid_disks);
1810 qd_idx = pd_idx + 1;
1811 if (pd_idx == raid_disks-1) {
1812 (*dd_idx)++; /* Q D D D P */
1814 } else if (*dd_idx >= pd_idx)
1815 (*dd_idx) += 2; /* D D P Q D */
1817 case ALGORITHM_LEFT_SYMMETRIC:
1818 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
1819 qd_idx = (pd_idx + 1) % raid_disks;
1820 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
1822 case ALGORITHM_RIGHT_SYMMETRIC:
1823 pd_idx = sector_div(stripe2, raid_disks);
1824 qd_idx = (pd_idx + 1) % raid_disks;
1825 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
1828 case ALGORITHM_PARITY_0:
1833 case ALGORITHM_PARITY_N:
1834 pd_idx = data_disks;
1835 qd_idx = data_disks + 1;
1838 case ALGORITHM_ROTATING_ZERO_RESTART:
1839 /* Exactly the same as RIGHT_ASYMMETRIC, but or
1840 * of blocks for computing Q is different.
1842 pd_idx = sector_div(stripe2, raid_disks);
1843 qd_idx = pd_idx + 1;
1844 if (pd_idx == raid_disks-1) {
1845 (*dd_idx)++; /* Q D D D P */
1847 } else if (*dd_idx >= pd_idx)
1848 (*dd_idx) += 2; /* D D P Q D */
1852 case ALGORITHM_ROTATING_N_RESTART:
1853 /* Same a left_asymmetric, by first stripe is
1854 * D D D P Q rather than
1858 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
1859 qd_idx = pd_idx + 1;
1860 if (pd_idx == raid_disks-1) {
1861 (*dd_idx)++; /* Q D D D P */
1863 } else if (*dd_idx >= pd_idx)
1864 (*dd_idx) += 2; /* D D P Q D */
1868 case ALGORITHM_ROTATING_N_CONTINUE:
1869 /* Same as left_symmetric but Q is before P */
1870 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
1871 qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
1872 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
1876 case ALGORITHM_LEFT_ASYMMETRIC_6:
1877 /* RAID5 left_asymmetric, with Q on last device */
1878 pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
1879 if (*dd_idx >= pd_idx)
1881 qd_idx = raid_disks - 1;
1884 case ALGORITHM_RIGHT_ASYMMETRIC_6:
1885 pd_idx = sector_div(stripe2, raid_disks-1);
1886 if (*dd_idx >= pd_idx)
1888 qd_idx = raid_disks - 1;
1891 case ALGORITHM_LEFT_SYMMETRIC_6:
1892 pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
1893 *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
1894 qd_idx = raid_disks - 1;
1897 case ALGORITHM_RIGHT_SYMMETRIC_6:
1898 pd_idx = sector_div(stripe2, raid_disks-1);
1899 *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
1900 qd_idx = raid_disks - 1;
1903 case ALGORITHM_PARITY_0_6:
1906 qd_idx = raid_disks - 1;
1916 sh->pd_idx = pd_idx;
1917 sh->qd_idx = qd_idx;
1918 sh->ddf_layout = ddf_layout;
1921 * Finally, compute the new sector number
1923 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
1928 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
1930 raid5_conf_t *conf = sh->raid_conf;
1931 int raid_disks = sh->disks;
1932 int data_disks = raid_disks - conf->max_degraded;
1933 sector_t new_sector = sh->sector, check;
1934 int sectors_per_chunk = previous ? conf->prev_chunk_sectors
1935 : conf->chunk_sectors;
1936 int algorithm = previous ? conf->prev_algo
1940 sector_t chunk_number;
1941 int dummy1, dd_idx = i;
1943 struct stripe_head sh2;
1946 chunk_offset = sector_div(new_sector, sectors_per_chunk);
1947 stripe = new_sector;
1949 if (i == sh->pd_idx)
1951 switch(conf->level) {
1954 switch (algorithm) {
1955 case ALGORITHM_LEFT_ASYMMETRIC:
1956 case ALGORITHM_RIGHT_ASYMMETRIC:
1960 case ALGORITHM_LEFT_SYMMETRIC:
1961 case ALGORITHM_RIGHT_SYMMETRIC:
1964 i -= (sh->pd_idx + 1);
1966 case ALGORITHM_PARITY_0:
1969 case ALGORITHM_PARITY_N:
1976 if (i == sh->qd_idx)
1977 return 0; /* It is the Q disk */
1978 switch (algorithm) {
1979 case ALGORITHM_LEFT_ASYMMETRIC:
1980 case ALGORITHM_RIGHT_ASYMMETRIC:
1981 case ALGORITHM_ROTATING_ZERO_RESTART:
1982 case ALGORITHM_ROTATING_N_RESTART:
1983 if (sh->pd_idx == raid_disks-1)
1984 i--; /* Q D D D P */
1985 else if (i > sh->pd_idx)
1986 i -= 2; /* D D P Q D */
1988 case ALGORITHM_LEFT_SYMMETRIC:
1989 case ALGORITHM_RIGHT_SYMMETRIC:
1990 if (sh->pd_idx == raid_disks-1)
1991 i--; /* Q D D D P */
1996 i -= (sh->pd_idx + 2);
1999 case ALGORITHM_PARITY_0:
2002 case ALGORITHM_PARITY_N:
2004 case ALGORITHM_ROTATING_N_CONTINUE:
2005 /* Like left_symmetric, but P is before Q */
2006 if (sh->pd_idx == 0)
2007 i--; /* P D D D Q */
2012 i -= (sh->pd_idx + 1);
2015 case ALGORITHM_LEFT_ASYMMETRIC_6:
2016 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2020 case ALGORITHM_LEFT_SYMMETRIC_6:
2021 case ALGORITHM_RIGHT_SYMMETRIC_6:
2023 i += data_disks + 1;
2024 i -= (sh->pd_idx + 1);
2026 case ALGORITHM_PARITY_0_6:
2035 chunk_number = stripe * data_disks + i;
2036 r_sector = chunk_number * sectors_per_chunk + chunk_offset;
2038 check = raid5_compute_sector(conf, r_sector,
2039 previous, &dummy1, &sh2);
2040 if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
2041 || sh2.qd_idx != sh->qd_idx) {
2042 printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
2043 mdname(conf->mddev));
2051 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
2052 int rcw, int expand)
2054 int i, pd_idx = sh->pd_idx, disks = sh->disks;
2055 raid5_conf_t *conf = sh->raid_conf;
2056 int level = conf->level;
2059 /* if we are not expanding this is a proper write request, and
2060 * there will be bios with new data to be drained into the
2064 sh->reconstruct_state = reconstruct_state_drain_run;
2065 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2067 sh->reconstruct_state = reconstruct_state_run;
2069 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2071 for (i = disks; i--; ) {
2072 struct r5dev *dev = &sh->dev[i];
2075 set_bit(R5_LOCKED, &dev->flags);
2076 set_bit(R5_Wantdrain, &dev->flags);
2078 clear_bit(R5_UPTODATE, &dev->flags);
2082 if (s->locked + conf->max_degraded == disks)
2083 if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2084 atomic_inc(&conf->pending_full_writes);
2087 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
2088 test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
2090 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
2091 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
2092 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2093 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2095 for (i = disks; i--; ) {
2096 struct r5dev *dev = &sh->dev[i];
2101 (test_bit(R5_UPTODATE, &dev->flags) ||
2102 test_bit(R5_Wantcompute, &dev->flags))) {
2103 set_bit(R5_Wantdrain, &dev->flags);
2104 set_bit(R5_LOCKED, &dev->flags);
2105 clear_bit(R5_UPTODATE, &dev->flags);
2111 /* keep the parity disk(s) locked while asynchronous operations
2114 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
2115 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2119 int qd_idx = sh->qd_idx;
2120 struct r5dev *dev = &sh->dev[qd_idx];
2122 set_bit(R5_LOCKED, &dev->flags);
2123 clear_bit(R5_UPTODATE, &dev->flags);
2127 pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2128 __func__, (unsigned long long)sh->sector,
2129 s->locked, s->ops_request);
2133 * Each stripe/dev can have one or more bion attached.
2134 * toread/towrite point to the first in a chain.
2135 * The bi_next chain must be in order.
2137 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
2140 raid5_conf_t *conf = sh->raid_conf;
2143 pr_debug("adding bi b#%llu to stripe s#%llu\n",
2144 (unsigned long long)bi->bi_sector,
2145 (unsigned long long)sh->sector);
2148 spin_lock_irq(&conf->device_lock);
2150 bip = &sh->dev[dd_idx].towrite;
2151 if (*bip == NULL && sh->dev[dd_idx].written == NULL)
2154 bip = &sh->dev[dd_idx].toread;
2155 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
2156 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
2158 bip = & (*bip)->bi_next;
2160 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
2163 BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
2167 bi->bi_phys_segments++;
2170 /* check if page is covered */
2171 sector_t sector = sh->dev[dd_idx].sector;
2172 for (bi=sh->dev[dd_idx].towrite;
2173 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
2174 bi && bi->bi_sector <= sector;
2175 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
2176 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
2177 sector = bi->bi_sector + (bi->bi_size>>9);
2179 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
2180 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
2182 spin_unlock_irq(&conf->device_lock);
2184 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
2185 (unsigned long long)(*bip)->bi_sector,
2186 (unsigned long long)sh->sector, dd_idx);
2188 if (conf->mddev->bitmap && firstwrite) {
2189 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
2191 sh->bm_seq = conf->seq_flush+1;
2192 set_bit(STRIPE_BIT_DELAY, &sh->state);
2197 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
2198 spin_unlock_irq(&conf->device_lock);
2202 static void end_reshape(raid5_conf_t *conf);
2204 static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
2205 struct stripe_head *sh)
2207 int sectors_per_chunk =
2208 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
2210 int chunk_offset = sector_div(stripe, sectors_per_chunk);
2211 int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2213 raid5_compute_sector(conf,
2214 stripe * (disks - conf->max_degraded)
2215 *sectors_per_chunk + chunk_offset,
2221 handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh,
2222 struct stripe_head_state *s, int disks,
2223 struct bio **return_bi)
2226 for (i = disks; i--; ) {
2230 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2233 rdev = rcu_dereference(conf->disks[i].rdev);
2234 if (rdev && test_bit(In_sync, &rdev->flags))
2235 /* multiple read failures in one stripe */
2236 md_error(conf->mddev, rdev);
2239 spin_lock_irq(&conf->device_lock);
2240 /* fail all writes first */
2241 bi = sh->dev[i].towrite;
2242 sh->dev[i].towrite = NULL;
2248 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
2249 wake_up(&conf->wait_for_overlap);
2251 while (bi && bi->bi_sector <
2252 sh->dev[i].sector + STRIPE_SECTORS) {
2253 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
2254 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2255 if (!raid5_dec_bi_phys_segments(bi)) {
2256 md_write_end(conf->mddev);
2257 bi->bi_next = *return_bi;
2262 /* and fail all 'written' */
2263 bi = sh->dev[i].written;
2264 sh->dev[i].written = NULL;
2265 if (bi) bitmap_end = 1;
2266 while (bi && bi->bi_sector <
2267 sh->dev[i].sector + STRIPE_SECTORS) {
2268 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
2269 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2270 if (!raid5_dec_bi_phys_segments(bi)) {
2271 md_write_end(conf->mddev);
2272 bi->bi_next = *return_bi;
2278 /* fail any reads if this device is non-operational and
2279 * the data has not reached the cache yet.
2281 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
2282 (!test_bit(R5_Insync, &sh->dev[i].flags) ||
2283 test_bit(R5_ReadError, &sh->dev[i].flags))) {
2284 bi = sh->dev[i].toread;
2285 sh->dev[i].toread = NULL;
2286 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
2287 wake_up(&conf->wait_for_overlap);
2288 if (bi) s->to_read--;
2289 while (bi && bi->bi_sector <
2290 sh->dev[i].sector + STRIPE_SECTORS) {
2291 struct bio *nextbi =
2292 r5_next_bio(bi, sh->dev[i].sector);
2293 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2294 if (!raid5_dec_bi_phys_segments(bi)) {
2295 bi->bi_next = *return_bi;
2301 spin_unlock_irq(&conf->device_lock);
2303 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
2304 STRIPE_SECTORS, 0, 0);
2305 /* If we were in the middle of a write the parity block might
2306 * still be locked - so just clear all R5_LOCKED flags
2308 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2311 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
2312 if (atomic_dec_and_test(&conf->pending_full_writes))
2313 md_wakeup_thread(conf->mddev->thread);
2316 /* fetch_block - checks the given member device to see if its data needs
2317 * to be read or computed to satisfy a request.
2319 * Returns 1 when no more member devices need to be checked, otherwise returns
2320 * 0 to tell the loop in handle_stripe_fill to continue
2322 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
2323 int disk_idx, int disks)
2325 struct r5dev *dev = &sh->dev[disk_idx];
2326 struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
2327 &sh->dev[s->failed_num[1]] };
2329 /* is the data in this block needed, and can we get it? */
2330 if (!test_bit(R5_LOCKED, &dev->flags) &&
2331 !test_bit(R5_UPTODATE, &dev->flags) &&
2333 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
2334 s->syncing || s->expanding ||
2335 (s->failed >= 1 && fdev[0]->toread) ||
2336 (s->failed >= 2 && fdev[1]->toread) ||
2337 (sh->raid_conf->level <= 5 && s->failed && fdev[0]->towrite &&
2338 !test_bit(R5_OVERWRITE, &fdev[0]->flags)) ||
2339 (sh->raid_conf->level == 6 && s->failed && s->to_write))) {
2340 /* we would like to get this block, possibly by computing it,
2341 * otherwise read it if the backing disk is insync
2343 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
2344 BUG_ON(test_bit(R5_Wantread, &dev->flags));
2345 if ((s->uptodate == disks - 1) &&
2346 (s->failed && (disk_idx == s->failed_num[0] ||
2347 disk_idx == s->failed_num[1]))) {
2348 /* have disk failed, and we're requested to fetch it;
2351 pr_debug("Computing stripe %llu block %d\n",
2352 (unsigned long long)sh->sector, disk_idx);
2353 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2354 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
2355 set_bit(R5_Wantcompute, &dev->flags);
2356 sh->ops.target = disk_idx;
2357 sh->ops.target2 = -1; /* no 2nd target */
2359 /* Careful: from this point on 'uptodate' is in the eye
2360 * of raid_run_ops which services 'compute' operations
2361 * before writes. R5_Wantcompute flags a block that will
2362 * be R5_UPTODATE by the time it is needed for a
2363 * subsequent operation.
2367 } else if (s->uptodate == disks-2 && s->failed >= 2) {
2368 /* Computing 2-failure is *very* expensive; only
2369 * do it if failed >= 2
2372 for (other = disks; other--; ) {
2373 if (other == disk_idx)
2375 if (!test_bit(R5_UPTODATE,
2376 &sh->dev[other].flags))
2380 pr_debug("Computing stripe %llu blocks %d,%d\n",
2381 (unsigned long long)sh->sector,
2383 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2384 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
2385 set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
2386 set_bit(R5_Wantcompute, &sh->dev[other].flags);
2387 sh->ops.target = disk_idx;
2388 sh->ops.target2 = other;
2392 } else if (test_bit(R5_Insync, &dev->flags)) {
2393 set_bit(R5_LOCKED, &dev->flags);
2394 set_bit(R5_Wantread, &dev->flags);
2396 pr_debug("Reading block %d (sync=%d)\n",
2397 disk_idx, s->syncing);
2405 * handle_stripe_fill - read or compute data to satisfy pending requests.
2407 static void handle_stripe_fill(struct stripe_head *sh,
2408 struct stripe_head_state *s,
2413 /* look for blocks to read/compute, skip this if a compute
2414 * is already in flight, or if the stripe contents are in the
2415 * midst of changing due to a write
2417 if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
2418 !sh->reconstruct_state)
2419 for (i = disks; i--; )
2420 if (fetch_block(sh, s, i, disks))
2422 set_bit(STRIPE_HANDLE, &sh->state);
2426 /* handle_stripe_clean_event
2427 * any written block on an uptodate or failed drive can be returned.
2428 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
2429 * never LOCKED, so we don't need to test 'failed' directly.
2431 static void handle_stripe_clean_event(raid5_conf_t *conf,
2432 struct stripe_head *sh, int disks, struct bio **return_bi)
2437 for (i = disks; i--; )
2438 if (sh->dev[i].written) {
2440 if (!test_bit(R5_LOCKED, &dev->flags) &&
2441 test_bit(R5_UPTODATE, &dev->flags)) {
2442 /* We can return any write requests */
2443 struct bio *wbi, *wbi2;
2445 pr_debug("Return write for disc %d\n", i);
2446 spin_lock_irq(&conf->device_lock);
2448 dev->written = NULL;
2449 while (wbi && wbi->bi_sector <
2450 dev->sector + STRIPE_SECTORS) {
2451 wbi2 = r5_next_bio(wbi, dev->sector);
2452 if (!raid5_dec_bi_phys_segments(wbi)) {
2453 md_write_end(conf->mddev);
2454 wbi->bi_next = *return_bi;
2459 if (dev->towrite == NULL)
2461 spin_unlock_irq(&conf->device_lock);
2463 bitmap_endwrite(conf->mddev->bitmap,
2466 !test_bit(STRIPE_DEGRADED, &sh->state),
2471 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
2472 if (atomic_dec_and_test(&conf->pending_full_writes))
2473 md_wakeup_thread(conf->mddev->thread);
2476 static void handle_stripe_dirtying(raid5_conf_t *conf,
2477 struct stripe_head *sh,
2478 struct stripe_head_state *s,
2481 int rmw = 0, rcw = 0, i;
2482 if (conf->max_degraded == 2) {
2483 /* RAID6 requires 'rcw' in current implementation
2484 * Calculate the real rcw later - for now fake it
2485 * look like rcw is cheaper
2488 } else for (i = disks; i--; ) {
2489 /* would I have to read this buffer for read_modify_write */
2490 struct r5dev *dev = &sh->dev[i];
2491 if ((dev->towrite || i == sh->pd_idx) &&
2492 !test_bit(R5_LOCKED, &dev->flags) &&
2493 !(test_bit(R5_UPTODATE, &dev->flags) ||
2494 test_bit(R5_Wantcompute, &dev->flags))) {
2495 if (test_bit(R5_Insync, &dev->flags))
2498 rmw += 2*disks; /* cannot read it */
2500 /* Would I have to read this buffer for reconstruct_write */
2501 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
2502 !test_bit(R5_LOCKED, &dev->flags) &&
2503 !(test_bit(R5_UPTODATE, &dev->flags) ||
2504 test_bit(R5_Wantcompute, &dev->flags))) {
2505 if (test_bit(R5_Insync, &dev->flags)) rcw++;
2510 pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2511 (unsigned long long)sh->sector, rmw, rcw);
2512 set_bit(STRIPE_HANDLE, &sh->state);
2513 if (rmw < rcw && rmw > 0)
2514 /* prefer read-modify-write, but need to get some data */
2515 for (i = disks; i--; ) {
2516 struct r5dev *dev = &sh->dev[i];
2517 if ((dev->towrite || i == sh->pd_idx) &&
2518 !test_bit(R5_LOCKED, &dev->flags) &&
2519 !(test_bit(R5_UPTODATE, &dev->flags) ||
2520 test_bit(R5_Wantcompute, &dev->flags)) &&
2521 test_bit(R5_Insync, &dev->flags)) {
2523 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2524 pr_debug("Read_old block "
2525 "%d for r-m-w\n", i);
2526 set_bit(R5_LOCKED, &dev->flags);
2527 set_bit(R5_Wantread, &dev->flags);
2530 set_bit(STRIPE_DELAYED, &sh->state);
2531 set_bit(STRIPE_HANDLE, &sh->state);
2535 if (rcw <= rmw && rcw > 0) {
2536 /* want reconstruct write, but need to get some data */
2538 for (i = disks; i--; ) {
2539 struct r5dev *dev = &sh->dev[i];
2540 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2541 i != sh->pd_idx && i != sh->qd_idx &&
2542 !test_bit(R5_LOCKED, &dev->flags) &&
2543 !(test_bit(R5_UPTODATE, &dev->flags) ||
2544 test_bit(R5_Wantcompute, &dev->flags))) {
2546 if (!test_bit(R5_Insync, &dev->flags))
2547 continue; /* it's a failed drive */
2549 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2550 pr_debug("Read_old block "
2551 "%d for Reconstruct\n", i);
2552 set_bit(R5_LOCKED, &dev->flags);
2553 set_bit(R5_Wantread, &dev->flags);
2556 set_bit(STRIPE_DELAYED, &sh->state);
2557 set_bit(STRIPE_HANDLE, &sh->state);
2562 /* now if nothing is locked, and if we have enough data,
2563 * we can start a write request
2565 /* since handle_stripe can be called at any time we need to handle the
2566 * case where a compute block operation has been submitted and then a
2567 * subsequent call wants to start a write request. raid_run_ops only
2568 * handles the case where compute block and reconstruct are requested
2569 * simultaneously. If this is not the case then new writes need to be
2570 * held off until the compute completes.
2572 if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
2573 (s->locked == 0 && (rcw == 0 || rmw == 0) &&
2574 !test_bit(STRIPE_BIT_DELAY, &sh->state)))
2575 schedule_reconstruction(sh, s, rcw == 0, 0);
2578 static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
2579 struct stripe_head_state *s, int disks)
2581 struct r5dev *dev = NULL;
2583 set_bit(STRIPE_HANDLE, &sh->state);
2585 switch (sh->check_state) {
2586 case check_state_idle:
2587 /* start a new check operation if there are no failures */
2588 if (s->failed == 0) {
2589 BUG_ON(s->uptodate != disks);
2590 sh->check_state = check_state_run;
2591 set_bit(STRIPE_OP_CHECK, &s->ops_request);
2592 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
2596 dev = &sh->dev[s->failed_num[0]];
2598 case check_state_compute_result:
2599 sh->check_state = check_state_idle;
2601 dev = &sh->dev[sh->pd_idx];
2603 /* check that a write has not made the stripe insync */
2604 if (test_bit(STRIPE_INSYNC, &sh->state))
2607 /* either failed parity check, or recovery is happening */
2608 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
2609 BUG_ON(s->uptodate != disks);
2611 set_bit(R5_LOCKED, &dev->flags);
2613 set_bit(R5_Wantwrite, &dev->flags);
2615 clear_bit(STRIPE_DEGRADED, &sh->state);
2616 set_bit(STRIPE_INSYNC, &sh->state);
2618 case check_state_run:
2619 break; /* we will be called again upon completion */
2620 case check_state_check_result:
2621 sh->check_state = check_state_idle;
2623 /* if a failure occurred during the check operation, leave
2624 * STRIPE_INSYNC not set and let the stripe be handled again
2629 /* handle a successful check operation, if parity is correct
2630 * we are done. Otherwise update the mismatch count and repair
2631 * parity if !MD_RECOVERY_CHECK
2633 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
2634 /* parity is correct (on disc,
2635 * not in buffer any more)
2637 set_bit(STRIPE_INSYNC, &sh->state);
2639 conf->mddev->resync_mismatches += STRIPE_SECTORS;
2640 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
2641 /* don't try to repair!! */
2642 set_bit(STRIPE_INSYNC, &sh->state);
2644 sh->check_state = check_state_compute_run;
2645 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2646 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
2647 set_bit(R5_Wantcompute,
2648 &sh->dev[sh->pd_idx].flags);
2649 sh->ops.target = sh->pd_idx;
2650 sh->ops.target2 = -1;
2655 case check_state_compute_run:
2658 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
2659 __func__, sh->check_state,
2660 (unsigned long long) sh->sector);
2666 static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh,
2667 struct stripe_head_state *s,
2670 int pd_idx = sh->pd_idx;
2671 int qd_idx = sh->qd_idx;
2674 set_bit(STRIPE_HANDLE, &sh->state);
2676 BUG_ON(s->failed > 2);
2678 /* Want to check and possibly repair P and Q.
2679 * However there could be one 'failed' device, in which
2680 * case we can only check one of them, possibly using the
2681 * other to generate missing data
2684 switch (sh->check_state) {
2685 case check_state_idle:
2686 /* start a new check operation if there are < 2 failures */
2687 if (s->failed == s->q_failed) {
2688 /* The only possible failed device holds Q, so it
2689 * makes sense to check P (If anything else were failed,
2690 * we would have used P to recreate it).
2692 sh->check_state = check_state_run;
2694 if (!s->q_failed && s->failed < 2) {
2695 /* Q is not failed, and we didn't use it to generate
2696 * anything, so it makes sense to check it
2698 if (sh->check_state == check_state_run)
2699 sh->check_state = check_state_run_pq;
2701 sh->check_state = check_state_run_q;
2704 /* discard potentially stale zero_sum_result */
2705 sh->ops.zero_sum_result = 0;
2707 if (sh->check_state == check_state_run) {
2708 /* async_xor_zero_sum destroys the contents of P */
2709 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2712 if (sh->check_state >= check_state_run &&
2713 sh->check_state <= check_state_run_pq) {
2714 /* async_syndrome_zero_sum preserves P and Q, so
2715 * no need to mark them !uptodate here
2717 set_bit(STRIPE_OP_CHECK, &s->ops_request);
2721 /* we have 2-disk failure */
2722 BUG_ON(s->failed != 2);
2724 case check_state_compute_result:
2725 sh->check_state = check_state_idle;
2727 /* check that a write has not made the stripe insync */
2728 if (test_bit(STRIPE_INSYNC, &sh->state))
2731 /* now write out any block on a failed drive,
2732 * or P or Q if they were recomputed
2734 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
2735 if (s->failed == 2) {
2736 dev = &sh->dev[s->failed_num[1]];
2738 set_bit(R5_LOCKED, &dev->flags);
2739 set_bit(R5_Wantwrite, &dev->flags);
2741 if (s->failed >= 1) {
2742 dev = &sh->dev[s->failed_num[0]];
2744 set_bit(R5_LOCKED, &dev->flags);
2745 set_bit(R5_Wantwrite, &dev->flags);
2747 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
2748 dev = &sh->dev[pd_idx];
2750 set_bit(R5_LOCKED, &dev->flags);
2751 set_bit(R5_Wantwrite, &dev->flags);
2753 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
2754 dev = &sh->dev[qd_idx];
2756 set_bit(R5_LOCKED, &dev->flags);
2757 set_bit(R5_Wantwrite, &dev->flags);
2759 clear_bit(STRIPE_DEGRADED, &sh->state);
2761 set_bit(STRIPE_INSYNC, &sh->state);
2763 case check_state_run:
2764 case check_state_run_q:
2765 case check_state_run_pq:
2766 break; /* we will be called again upon completion */
2767 case check_state_check_result:
2768 sh->check_state = check_state_idle;
2770 /* handle a successful check operation, if parity is correct
2771 * we are done. Otherwise update the mismatch count and repair
2772 * parity if !MD_RECOVERY_CHECK
2774 if (sh->ops.zero_sum_result == 0) {
2775 /* both parities are correct */
2777 set_bit(STRIPE_INSYNC, &sh->state);
2779 /* in contrast to the raid5 case we can validate
2780 * parity, but still have a failure to write
2783 sh->check_state = check_state_compute_result;
2784 /* Returning at this point means that we may go
2785 * off and bring p and/or q uptodate again so
2786 * we make sure to check zero_sum_result again
2787 * to verify if p or q need writeback
2791 conf->mddev->resync_mismatches += STRIPE_SECTORS;
2792 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
2793 /* don't try to repair!! */
2794 set_bit(STRIPE_INSYNC, &sh->state);
2796 int *target = &sh->ops.target;
2798 sh->ops.target = -1;
2799 sh->ops.target2 = -1;
2800 sh->check_state = check_state_compute_run;
2801 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2802 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
2803 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
2804 set_bit(R5_Wantcompute,
2805 &sh->dev[pd_idx].flags);
2807 target = &sh->ops.target2;
2810 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
2811 set_bit(R5_Wantcompute,
2812 &sh->dev[qd_idx].flags);
2819 case check_state_compute_run:
2822 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
2823 __func__, sh->check_state,
2824 (unsigned long long) sh->sector);
2829 static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh)
2833 /* We have read all the blocks in this stripe and now we need to
2834 * copy some of them into a target stripe for expand.
2836 struct dma_async_tx_descriptor *tx = NULL;
2837 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
2838 for (i = 0; i < sh->disks; i++)
2839 if (i != sh->pd_idx && i != sh->qd_idx) {
2841 struct stripe_head *sh2;
2842 struct async_submit_ctl submit;
2844 sector_t bn = compute_blocknr(sh, i, 1);
2845 sector_t s = raid5_compute_sector(conf, bn, 0,
2847 sh2 = get_active_stripe(conf, s, 0, 1, 1);
2849 /* so far only the early blocks of this stripe
2850 * have been requested. When later blocks
2851 * get requested, we will try again
2854 if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
2855 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
2856 /* must have already done this block */
2857 release_stripe(sh2);
2861 /* place all the copies on one channel */
2862 init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
2863 tx = async_memcpy(sh2->dev[dd_idx].page,
2864 sh->dev[i].page, 0, 0, STRIPE_SIZE,
2867 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
2868 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
2869 for (j = 0; j < conf->raid_disks; j++)
2870 if (j != sh2->pd_idx &&
2872 !test_bit(R5_Expanded, &sh2->dev[j].flags))
2874 if (j == conf->raid_disks) {
2875 set_bit(STRIPE_EXPAND_READY, &sh2->state);
2876 set_bit(STRIPE_HANDLE, &sh2->state);
2878 release_stripe(sh2);
2881 /* done submitting copies, wait for them to complete */
2884 dma_wait_for_async_tx(tx);
2890 * handle_stripe - do things to a stripe.
2892 * We lock the stripe and then examine the state of various bits
2893 * to see what needs to be done.
2895 * return some read request which now have data
2896 * return some write requests which are safely on disc
2897 * schedule a read on some buffers
2898 * schedule a write of some buffers
2899 * return confirmation of parity correctness
2901 * buffers are taken off read_list or write_list, and bh_cache buffers
2902 * get BH_Lock set before the stripe lock is released.
2906 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
2908 raid5_conf_t *conf = sh->raid_conf;
2909 int disks = sh->disks;
2913 memset(s, 0, sizeof(*s));
2915 s->syncing = test_bit(STRIPE_SYNCING, &sh->state);
2916 s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
2917 s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
2918 s->failed_num[0] = -1;
2919 s->failed_num[1] = -1;
2921 /* Now to look around and see what can be done */
2923 spin_lock_irq(&conf->device_lock);
2924 for (i=disks; i--; ) {
2929 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
2930 i, dev->flags, dev->toread, dev->towrite, dev->written);
2931 /* maybe we can reply to a read
2933 * new wantfill requests are only permitted while
2934 * ops_complete_biofill is guaranteed to be inactive
2936 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
2937 !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
2938 set_bit(R5_Wantfill, &dev->flags);
2940 /* now count some things */
2941 if (test_bit(R5_LOCKED, &dev->flags))
2943 if (test_bit(R5_UPTODATE, &dev->flags))
2945 if (test_bit(R5_Wantcompute, &dev->flags)) {
2947 BUG_ON(s->compute > 2);
2950 if (test_bit(R5_Wantfill, &dev->flags))
2952 else if (dev->toread)
2956 if (!test_bit(R5_OVERWRITE, &dev->flags))
2961 rdev = rcu_dereference(conf->disks[i].rdev);
2962 if (s->blocked_rdev == NULL &&
2963 rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
2964 s->blocked_rdev = rdev;
2965 atomic_inc(&rdev->nr_pending);
2967 clear_bit(R5_Insync, &dev->flags);
2970 else if (test_bit(In_sync, &rdev->flags))
2971 set_bit(R5_Insync, &dev->flags);
2973 /* in sync if before recovery_offset */
2974 if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
2975 set_bit(R5_Insync, &dev->flags);
2977 if (!test_bit(R5_Insync, &dev->flags)) {
2978 /* The ReadError flag will just be confusing now */
2979 clear_bit(R5_ReadError, &dev->flags);
2980 clear_bit(R5_ReWrite, &dev->flags);
2982 if (test_bit(R5_ReadError, &dev->flags))
2983 clear_bit(R5_Insync, &dev->flags);
2984 if (!test_bit(R5_Insync, &dev->flags)) {
2986 s->failed_num[s->failed] = i;
2990 spin_unlock_irq(&conf->device_lock);
2994 static void handle_stripe(struct stripe_head *sh)
2996 struct stripe_head_state s;
2997 raid5_conf_t *conf = sh->raid_conf;
3000 int disks = sh->disks;
3001 struct r5dev *pdev, *qdev;
3003 clear_bit(STRIPE_HANDLE, &sh->state);
3004 if (test_and_set_bit(STRIPE_ACTIVE, &sh->state)) {
3005 /* already being handled, ensure it gets handled
3006 * again when current action finishes */
3007 set_bit(STRIPE_HANDLE, &sh->state);
3011 if (test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
3012 set_bit(STRIPE_SYNCING, &sh->state);
3013 clear_bit(STRIPE_INSYNC, &sh->state);
3015 clear_bit(STRIPE_DELAYED, &sh->state);
3017 pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
3018 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
3019 (unsigned long long)sh->sector, sh->state,
3020 atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
3021 sh->check_state, sh->reconstruct_state);
3023 analyse_stripe(sh, &s);
3025 if (unlikely(s.blocked_rdev)) {
3026 if (s.syncing || s.expanding || s.expanded ||
3027 s.to_write || s.written) {
3028 set_bit(STRIPE_HANDLE, &sh->state);
3031 /* There is nothing for the blocked_rdev to block */
3032 rdev_dec_pending(s.blocked_rdev, conf->mddev);
3033 s.blocked_rdev = NULL;
3036 if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
3037 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
3038 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
3041 pr_debug("locked=%d uptodate=%d to_read=%d"
3042 " to_write=%d failed=%d failed_num=%d,%d\n",
3043 s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
3044 s.failed_num[0], s.failed_num[1]);
3045 /* check if the array has lost more than max_degraded devices and,
3046 * if so, some requests might need to be failed.
3048 if (s.failed > conf->max_degraded && s.to_read+s.to_write+s.written)
3049 handle_failed_stripe(conf, sh, &s, disks, &s.return_bi);
3050 if (s.failed > conf->max_degraded && s.syncing) {
3051 md_done_sync(conf->mddev, STRIPE_SECTORS, 0);
3052 clear_bit(STRIPE_SYNCING, &sh->state);
3057 * might be able to return some write requests if the parity blocks
3058 * are safe, or on a failed drive
3060 pdev = &sh->dev[sh->pd_idx];
3061 s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
3062 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
3063 qdev = &sh->dev[sh->qd_idx];
3064 s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
3065 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
3069 (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
3070 && !test_bit(R5_LOCKED, &pdev->flags)
3071 && test_bit(R5_UPTODATE, &pdev->flags)))) &&
3072 (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
3073 && !test_bit(R5_LOCKED, &qdev->flags)
3074 && test_bit(R5_UPTODATE, &qdev->flags)))))
3075 handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
3077 /* Now we might consider reading some blocks, either to check/generate
3078 * parity, or to satisfy requests
3079 * or to load a block that is being partially written.
3081 if (s.to_read || s.non_overwrite
3082 || (conf->level == 6 && s.to_write && s.failed)
3083 || (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
3084 handle_stripe_fill(sh, &s, disks);
3086 /* Now we check to see if any write operations have recently
3090 if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
3092 if (sh->reconstruct_state == reconstruct_state_drain_result ||
3093 sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
3094 sh->reconstruct_state = reconstruct_state_idle;
3096 /* All the 'written' buffers and the parity block are ready to
3097 * be written back to disk
3099 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags));
3100 BUG_ON(sh->qd_idx >= 0 &&
3101 !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags));
3102 for (i = disks; i--; ) {
3103 struct r5dev *dev = &sh->dev[i];
3104 if (test_bit(R5_LOCKED, &dev->flags) &&
3105 (i == sh->pd_idx || i == sh->qd_idx ||
3107 pr_debug("Writing block %d\n", i);
3108 set_bit(R5_Wantwrite, &dev->flags);
3111 if (!test_bit(R5_Insync, &dev->flags) ||
3112 ((i == sh->pd_idx || i == sh->qd_idx) &&
3114 set_bit(STRIPE_INSYNC, &sh->state);
3117 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3118 s.dec_preread_active = 1;
3121 /* Now to consider new write requests and what else, if anything
3122 * should be read. We do not handle new writes when:
3123 * 1/ A 'write' operation (copy+xor) is already in flight.
3124 * 2/ A 'check' operation is in flight, as it may clobber the parity
3127 if (s.to_write && !sh->reconstruct_state && !sh->check_state)
3128 handle_stripe_dirtying(conf, sh, &s, disks);
3130 /* maybe we need to check and possibly fix the parity for this stripe
3131 * Any reads will already have been scheduled, so we just see if enough
3132 * data is available. The parity check is held off while parity
3133 * dependent operations are in flight.
3135 if (sh->check_state ||
3136 (s.syncing && s.locked == 0 &&
3137 !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
3138 !test_bit(STRIPE_INSYNC, &sh->state))) {
3139 if (conf->level == 6)
3140 handle_parity_checks6(conf, sh, &s, disks);
3142 handle_parity_checks5(conf, sh, &s, disks);
3145 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
3146 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
3147 clear_bit(STRIPE_SYNCING, &sh->state);
3150 /* If the failed drives are just a ReadError, then we might need
3151 * to progress the repair/check process
3153 if (s.failed <= conf->max_degraded && !conf->mddev->ro)
3154 for (i = 0; i < s.failed; i++) {
3155 struct r5dev *dev = &sh->dev[s.failed_num[i]];
3156 if (test_bit(R5_ReadError, &dev->flags)
3157 && !test_bit(R5_LOCKED, &dev->flags)
3158 && test_bit(R5_UPTODATE, &dev->flags)
3160 if (!test_bit(R5_ReWrite, &dev->flags)) {
3161 set_bit(R5_Wantwrite, &dev->flags);
3162 set_bit(R5_ReWrite, &dev->flags);
3163 set_bit(R5_LOCKED, &dev->flags);
3166 /* let's read it back */
3167 set_bit(R5_Wantread, &dev->flags);
3168 set_bit(R5_LOCKED, &dev->flags);
3175 /* Finish reconstruct operations initiated by the expansion process */
3176 if (sh->reconstruct_state == reconstruct_state_result) {
3177 struct stripe_head *sh_src
3178 = get_active_stripe(conf, sh->sector, 1, 1, 1);
3179 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
3180 /* sh cannot be written until sh_src has been read.
3181 * so arrange for sh to be delayed a little
3183 set_bit(STRIPE_DELAYED, &sh->state);
3184 set_bit(STRIPE_HANDLE, &sh->state);
3185 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
3187 atomic_inc(&conf->preread_active_stripes);
3188 release_stripe(sh_src);
3192 release_stripe(sh_src);
3194 sh->reconstruct_state = reconstruct_state_idle;
3195 clear_bit(STRIPE_EXPANDING, &sh->state);
3196 for (i = conf->raid_disks; i--; ) {
3197 set_bit(R5_Wantwrite, &sh->dev[i].flags);
3198 set_bit(R5_LOCKED, &sh->dev[i].flags);
3203 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
3204 !sh->reconstruct_state) {
3205 /* Need to write out all blocks after computing parity */
3206 sh->disks = conf->raid_disks;
3207 stripe_set_idx(sh->sector, conf, 0, sh);
3208 schedule_reconstruction(sh, &s, 1, 1);
3209 } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
3210 clear_bit(STRIPE_EXPAND_READY, &sh->state);
3211 atomic_dec(&conf->reshape_stripes);
3212 wake_up(&conf->wait_for_overlap);
3213 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
3216 if (s.expanding && s.locked == 0 &&
3217 !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
3218 handle_stripe_expansion(conf, sh);
3221 /* wait for this device to become unblocked */
3222 if (unlikely(s.blocked_rdev))
3223 md_wait_for_blocked_rdev(s.blocked_rdev, conf->mddev);
3226 raid_run_ops(sh, s.ops_request);
3231 if (s.dec_preread_active) {
3232 /* We delay this until after ops_run_io so that if make_request
3233 * is waiting on a flush, it won't continue until the writes
3234 * have actually been submitted.
3236 atomic_dec(&conf->preread_active_stripes);
3237 if (atomic_read(&conf->preread_active_stripes) <
3239 md_wakeup_thread(conf->mddev->thread);
3242 return_io(s.return_bi);
3244 clear_bit(STRIPE_ACTIVE, &sh->state);
3247 static void raid5_activate_delayed(raid5_conf_t *conf)
3249 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
3250 while (!list_empty(&conf->delayed_list)) {
3251 struct list_head *l = conf->delayed_list.next;
3252 struct stripe_head *sh;
3253 sh = list_entry(l, struct stripe_head, lru);
3255 clear_bit(STRIPE_DELAYED, &sh->state);
3256 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3257 atomic_inc(&conf->preread_active_stripes);
3258 list_add_tail(&sh->lru, &conf->hold_list);
3263 static void activate_bit_delay(raid5_conf_t *conf)
3265 /* device_lock is held */
3266 struct list_head head;
3267 list_add(&head, &conf->bitmap_list);
3268 list_del_init(&conf->bitmap_list);
3269 while (!list_empty(&head)) {
3270 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
3271 list_del_init(&sh->lru);
3272 atomic_inc(&sh->count);
3273 __release_stripe(conf, sh);
3277 int md_raid5_congested(mddev_t *mddev, int bits)
3279 raid5_conf_t *conf = mddev->private;
3281 /* No difference between reads and writes. Just check
3282 * how busy the stripe_cache is
3285 if (conf->inactive_blocked)
3289 if (list_empty_careful(&conf->inactive_list))
3294 EXPORT_SYMBOL_GPL(md_raid5_congested);
3296 static int raid5_congested(void *data, int bits)
3298 mddev_t *mddev = data;
3300 return mddev_congested(mddev, bits) ||
3301 md_raid5_congested(mddev, bits);
3304 /* We want read requests to align with chunks where possible,
3305 * but write requests don't need to.
3307 static int raid5_mergeable_bvec(struct request_queue *q,
3308 struct bvec_merge_data *bvm,
3309 struct bio_vec *biovec)
3311 mddev_t *mddev = q->queuedata;
3312 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3314 unsigned int chunk_sectors = mddev->chunk_sectors;
3315 unsigned int bio_sectors = bvm->bi_size >> 9;
3317 if ((bvm->bi_rw & 1) == WRITE)
3318 return biovec->bv_len; /* always allow writes to be mergeable */
3320 if (mddev->new_chunk_sectors < mddev->chunk_sectors)
3321 chunk_sectors = mddev->new_chunk_sectors;
3322 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
3323 if (max < 0) max = 0;
3324 if (max <= biovec->bv_len && bio_sectors == 0)
3325 return biovec->bv_len;
3331 static int in_chunk_boundary(mddev_t *mddev, struct bio *bio)
3333 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3334 unsigned int chunk_sectors = mddev->chunk_sectors;
3335 unsigned int bio_sectors = bio->bi_size >> 9;
3337 if (mddev->new_chunk_sectors < mddev->chunk_sectors)
3338 chunk_sectors = mddev->new_chunk_sectors;
3339 return chunk_sectors >=
3340 ((sector & (chunk_sectors - 1)) + bio_sectors);
3344 * add bio to the retry LIFO ( in O(1) ... we are in interrupt )
3345 * later sampled by raid5d.
3347 static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf)
3349 unsigned long flags;
3351 spin_lock_irqsave(&conf->device_lock, flags);
3353 bi->bi_next = conf->retry_read_aligned_list;
3354 conf->retry_read_aligned_list = bi;
3356 spin_unlock_irqrestore(&conf->device_lock, flags);
3357 md_wakeup_thread(conf->mddev->thread);
3361 static struct bio *remove_bio_from_retry(raid5_conf_t *conf)
3365 bi = conf->retry_read_aligned;
3367 conf->retry_read_aligned = NULL;
3370 bi = conf->retry_read_aligned_list;
3372 conf->retry_read_aligned_list = bi->bi_next;
3375 * this sets the active strip count to 1 and the processed
3376 * strip count to zero (upper 8 bits)
3378 bi->bi_phys_segments = 1; /* biased count of active stripes */
3386 * The "raid5_align_endio" should check if the read succeeded and if it
3387 * did, call bio_endio on the original bio (having bio_put the new bio
3389 * If the read failed..
3391 static void raid5_align_endio(struct bio *bi, int error)
3393 struct bio* raid_bi = bi->bi_private;
3396 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3401 rdev = (void*)raid_bi->bi_next;
3402 raid_bi->bi_next = NULL;
3403 mddev = rdev->mddev;
3404 conf = mddev->private;
3406 rdev_dec_pending(rdev, conf->mddev);
3408 if (!error && uptodate) {
3409 bio_endio(raid_bi, 0);
3410 if (atomic_dec_and_test(&conf->active_aligned_reads))
3411 wake_up(&conf->wait_for_stripe);
3416 pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3418 add_bio_to_retry(raid_bi, conf);
3421 static int bio_fits_rdev(struct bio *bi)
3423 struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3425 if ((bi->bi_size>>9) > queue_max_sectors(q))
3427 blk_recount_segments(q, bi);
3428 if (bi->bi_phys_segments > queue_max_segments(q))
3431 if (q->merge_bvec_fn)
3432 /* it's too hard to apply the merge_bvec_fn at this stage,
3441 static int chunk_aligned_read(mddev_t *mddev, struct bio * raid_bio)
3443 raid5_conf_t *conf = mddev->private;
3445 struct bio* align_bi;
3448 if (!in_chunk_boundary(mddev, raid_bio)) {
3449 pr_debug("chunk_aligned_read : non aligned\n");
3453 * use bio_clone_mddev to make a copy of the bio
3455 align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
3459 * set bi_end_io to a new function, and set bi_private to the
3462 align_bi->bi_end_io = raid5_align_endio;
3463 align_bi->bi_private = raid_bio;
3467 align_bi->bi_sector = raid5_compute_sector(conf, raid_bio->bi_sector,
3472 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
3473 if (rdev && test_bit(In_sync, &rdev->flags)) {
3474 atomic_inc(&rdev->nr_pending);
3476 raid_bio->bi_next = (void*)rdev;
3477 align_bi->bi_bdev = rdev->bdev;
3478 align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);
3479 align_bi->bi_sector += rdev->data_offset;
3481 if (!bio_fits_rdev(align_bi)) {
3482 /* too big in some way */
3484 rdev_dec_pending(rdev, mddev);
3488 spin_lock_irq(&conf->device_lock);
3489 wait_event_lock_irq(conf->wait_for_stripe,
3491 conf->device_lock, /* nothing */);
3492 atomic_inc(&conf->active_aligned_reads);
3493 spin_unlock_irq(&conf->device_lock);
3495 generic_make_request(align_bi);
3504 /* __get_priority_stripe - get the next stripe to process
3506 * Full stripe writes are allowed to pass preread active stripes up until
3507 * the bypass_threshold is exceeded. In general the bypass_count
3508 * increments when the handle_list is handled before the hold_list; however, it
3509 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
3510 * stripe with in flight i/o. The bypass_count will be reset when the
3511 * head of the hold_list has changed, i.e. the head was promoted to the
3514 static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf)
3516 struct stripe_head *sh;
3518 pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
3520 list_empty(&conf->handle_list) ? "empty" : "busy",
3521 list_empty(&conf->hold_list) ? "empty" : "busy",
3522 atomic_read(&conf->pending_full_writes), conf->bypass_count);
3524 if (!list_empty(&conf->handle_list)) {
3525 sh = list_entry(conf->handle_list.next, typeof(*sh), lru);
3527 if (list_empty(&conf->hold_list))
3528 conf->bypass_count = 0;
3529 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
3530 if (conf->hold_list.next == conf->last_hold)
3531 conf->bypass_count++;
3533 conf->last_hold = conf->hold_list.next;
3534 conf->bypass_count -= conf->bypass_threshold;
3535 if (conf->bypass_count < 0)
3536 conf->bypass_count = 0;
3539 } else if (!list_empty(&conf->hold_list) &&
3540 ((conf->bypass_threshold &&
3541 conf->bypass_count > conf->bypass_threshold) ||
3542 atomic_read(&conf->pending_full_writes) == 0)) {
3543 sh = list_entry(conf->hold_list.next,
3545 conf->bypass_count -= conf->bypass_threshold;
3546 if (conf->bypass_count < 0)
3547 conf->bypass_count = 0;
3551 list_del_init(&sh->lru);
3552 atomic_inc(&sh->count);
3553 BUG_ON(atomic_read(&sh->count) != 1);
3557 static int make_request(mddev_t *mddev, struct bio * bi)
3559 raid5_conf_t *conf = mddev->private;
3561 sector_t new_sector;
3562 sector_t logical_sector, last_sector;
3563 struct stripe_head *sh;
3564 const int rw = bio_data_dir(bi);
3568 if (unlikely(bi->bi_rw & REQ_FLUSH)) {
3569 md_flush_request(mddev, bi);
3573 md_write_start(mddev, bi);
3576 mddev->reshape_position == MaxSector &&
3577 chunk_aligned_read(mddev,bi))
3580 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
3581 last_sector = bi->bi_sector + (bi->bi_size>>9);
3583 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
3585 plugged = mddev_check_plugged(mddev);
3586 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
3588 int disks, data_disks;
3593 disks = conf->raid_disks;
3594 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
3595 if (unlikely(conf->reshape_progress != MaxSector)) {
3596 /* spinlock is needed as reshape_progress may be
3597 * 64bit on a 32bit platform, and so it might be
3598 * possible to see a half-updated value
3599 * Of course reshape_progress could change after
3600 * the lock is dropped, so once we get a reference
3601 * to the stripe that we think it is, we will have
3604 spin_lock_irq(&conf->device_lock);
3605 if (mddev->delta_disks < 0
3606 ? logical_sector < conf->reshape_progress
3607 : logical_sector >= conf->reshape_progress) {
3608 disks = conf->previous_raid_disks;
3611 if (mddev->delta_disks < 0
3612 ? logical_sector < conf->reshape_safe
3613 : logical_sector >= conf->reshape_safe) {
3614 spin_unlock_irq(&conf->device_lock);
3619 spin_unlock_irq(&conf->device_lock);
3621 data_disks = disks - conf->max_degraded;
3623 new_sector = raid5_compute_sector(conf, logical_sector,
3626 pr_debug("raid456: make_request, sector %llu logical %llu\n",
3627 (unsigned long long)new_sector,
3628 (unsigned long long)logical_sector);
3630 sh = get_active_stripe(conf, new_sector, previous,
3631 (bi->bi_rw&RWA_MASK), 0);
3633 if (unlikely(previous)) {
3634 /* expansion might have moved on while waiting for a
3635 * stripe, so we must do the range check again.
3636 * Expansion could still move past after this
3637 * test, but as we are holding a reference to
3638 * 'sh', we know that if that happens,
3639 * STRIPE_EXPANDING will get set and the expansion
3640 * won't proceed until we finish with the stripe.
3643 spin_lock_irq(&conf->device_lock);
3644 if (mddev->delta_disks < 0
3645 ? logical_sector >= conf->reshape_progress
3646 : logical_sector < conf->reshape_progress)
3647 /* mismatch, need to try again */
3649 spin_unlock_irq(&conf->device_lock);
3658 logical_sector >= mddev->suspend_lo &&
3659 logical_sector < mddev->suspend_hi) {
3661 /* As the suspend_* range is controlled by
3662 * userspace, we want an interruptible
3665 flush_signals(current);
3666 prepare_to_wait(&conf->wait_for_overlap,
3667 &w, TASK_INTERRUPTIBLE);
3668 if (logical_sector >= mddev->suspend_lo &&
3669 logical_sector < mddev->suspend_hi)
3674 if (test_bit(STRIPE_EXPANDING, &sh->state) ||
3675 !add_stripe_bio(sh, bi, dd_idx, rw)) {
3676 /* Stripe is busy expanding or
3677 * add failed due to overlap. Flush everything
3680 md_wakeup_thread(mddev->thread);
3685 finish_wait(&conf->wait_for_overlap, &w);
3686 set_bit(STRIPE_HANDLE, &sh->state);
3687 clear_bit(STRIPE_DELAYED, &sh->state);
3688 if ((bi->bi_rw & REQ_SYNC) &&
3689 !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3690 atomic_inc(&conf->preread_active_stripes);
3693 /* cannot get stripe for read-ahead, just give-up */
3694 clear_bit(BIO_UPTODATE, &bi->bi_flags);
3695 finish_wait(&conf->wait_for_overlap, &w);
3701 md_wakeup_thread(mddev->thread);
3703 spin_lock_irq(&conf->device_lock);
3704 remaining = raid5_dec_bi_phys_segments(bi);
3705 spin_unlock_irq(&conf->device_lock);
3706 if (remaining == 0) {
3709 md_write_end(mddev);
3717 static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks);
3719 static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped)
3721 /* reshaping is quite different to recovery/resync so it is
3722 * handled quite separately ... here.
3724 * On each call to sync_request, we gather one chunk worth of
3725 * destination stripes and flag them as expanding.
3726 * Then we find all the source stripes and request reads.
3727 * As the reads complete, handle_stripe will copy the data
3728 * into the destination stripe and release that stripe.
3730 raid5_conf_t *conf = mddev->private;
3731 struct stripe_head *sh;
3732 sector_t first_sector, last_sector;
3733 int raid_disks = conf->previous_raid_disks;
3734 int data_disks = raid_disks - conf->max_degraded;
3735 int new_data_disks = conf->raid_disks - conf->max_degraded;
3738 sector_t writepos, readpos, safepos;
3739 sector_t stripe_addr;
3740 int reshape_sectors;
3741 struct list_head stripes;
3743 if (sector_nr == 0) {
3744 /* If restarting in the middle, skip the initial sectors */
3745 if (mddev->delta_disks < 0 &&
3746 conf->reshape_progress < raid5_size(mddev, 0, 0)) {
3747 sector_nr = raid5_size(mddev, 0, 0)
3748 - conf->reshape_progress;
3749 } else if (mddev->delta_disks >= 0 &&
3750 conf->reshape_progress > 0)
3751 sector_nr = conf->reshape_progress;
3752 sector_div(sector_nr, new_data_disks);
3754 mddev->curr_resync_completed = sector_nr;
3755 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
3761 /* We need to process a full chunk at a time.
3762 * If old and new chunk sizes differ, we need to process the
3765 if (mddev->new_chunk_sectors > mddev->chunk_sectors)
3766 reshape_sectors = mddev->new_chunk_sectors;
3768 reshape_sectors = mddev->chunk_sectors;
3770 /* we update the metadata when there is more than 3Meg
3771 * in the block range (that is rather arbitrary, should
3772 * probably be time based) or when the data about to be
3773 * copied would over-write the source of the data at
3774 * the front of the range.
3775 * i.e. one new_stripe along from reshape_progress new_maps
3776 * to after where reshape_safe old_maps to
3778 writepos = conf->reshape_progress;
3779 sector_div(writepos, new_data_disks);
3780 readpos = conf->reshape_progress;
3781 sector_div(readpos, data_disks);
3782 safepos = conf->reshape_safe;
3783 sector_div(safepos, data_disks);
3784 if (mddev->delta_disks < 0) {
3785 writepos -= min_t(sector_t, reshape_sectors, writepos);
3786 readpos += reshape_sectors;
3787 safepos += reshape_sectors;
3789 writepos += reshape_sectors;
3790 readpos -= min_t(sector_t, reshape_sectors, readpos);
3791 safepos -= min_t(sector_t, reshape_sectors, safepos);
3794 /* 'writepos' is the most advanced device address we might write.
3795 * 'readpos' is the least advanced device address we might read.
3796 * 'safepos' is the least address recorded in the metadata as having
3798 * If 'readpos' is behind 'writepos', then there is no way that we can
3799 * ensure safety in the face of a crash - that must be done by userspace
3800 * making a backup of the data. So in that case there is no particular
3801 * rush to update metadata.
3802 * Otherwise if 'safepos' is behind 'writepos', then we really need to
3803 * update the metadata to advance 'safepos' to match 'readpos' so that
3804 * we can be safe in the event of a crash.
3805 * So we insist on updating metadata if safepos is behind writepos and
3806 * readpos is beyond writepos.
3807 * In any case, update the metadata every 10 seconds.
3808 * Maybe that number should be configurable, but I'm not sure it is
3809 * worth it.... maybe it could be a multiple of safemode_delay???
3811 if ((mddev->delta_disks < 0
3812 ? (safepos > writepos && readpos < writepos)
3813 : (safepos < writepos && readpos > writepos)) ||
3814 time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
3815 /* Cannot proceed until we've updated the superblock... */
3816 wait_event(conf->wait_for_overlap,
3817 atomic_read(&conf->reshape_stripes)==0);
3818 mddev->reshape_position = conf->reshape_progress;
3819 mddev->curr_resync_completed = sector_nr;
3820 conf->reshape_checkpoint = jiffies;
3821 set_bit(MD_CHANGE_DEVS, &mddev->flags);
3822 md_wakeup_thread(mddev->thread);
3823 wait_event(mddev->sb_wait, mddev->flags == 0 ||
3824 kthread_should_stop());
3825 spin_lock_irq(&conf->device_lock);
3826 conf->reshape_safe = mddev->reshape_position;
3827 spin_unlock_irq(&conf->device_lock);
3828 wake_up(&conf->wait_for_overlap);
3829 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
3832 if (mddev->delta_disks < 0) {
3833 BUG_ON(conf->reshape_progress == 0);
3834 stripe_addr = writepos;
3835 BUG_ON((mddev->dev_sectors &
3836 ~((sector_t)reshape_sectors - 1))
3837 - reshape_sectors - stripe_addr
3840 BUG_ON(writepos != sector_nr + reshape_sectors);
3841 stripe_addr = sector_nr;
3843 INIT_LIST_HEAD(&stripes);
3844 for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
3846 int skipped_disk = 0;
3847 sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
3848 set_bit(STRIPE_EXPANDING, &sh->state);
3849 atomic_inc(&conf->reshape_stripes);
3850 /* If any of this stripe is beyond the end of the old
3851 * array, then we need to zero those blocks
3853 for (j=sh->disks; j--;) {
3855 if (j == sh->pd_idx)
3857 if (conf->level == 6 &&
3860 s = compute_blocknr(sh, j, 0);
3861 if (s < raid5_size(mddev, 0, 0)) {
3865 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
3866 set_bit(R5_Expanded, &sh->dev[j].flags);
3867 set_bit(R5_UPTODATE, &sh->dev[j].flags);
3869 if (!skipped_disk) {
3870 set_bit(STRIPE_EXPAND_READY, &sh->state);
3871 set_bit(STRIPE_HANDLE, &sh->state);
3873 list_add(&sh->lru, &stripes);
3875 spin_lock_irq(&conf->device_lock);
3876 if (mddev->delta_disks < 0)
3877 conf->reshape_progress -= reshape_sectors * new_data_disks;
3879 conf->reshape_progress += reshape_sectors * new_data_disks;
3880 spin_unlock_irq(&conf->device_lock);
3881 /* Ok, those stripe are ready. We can start scheduling
3882 * reads on the source stripes.
3883 * The source stripes are determined by mapping the first and last
3884 * block on the destination stripes.
3887 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
3890 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
3891 * new_data_disks - 1),
3893 if (last_sector >= mddev->dev_sectors)
3894 last_sector = mddev->dev_sectors - 1;
3895 while (first_sector <= last_sector) {
3896 sh = get_active_stripe(conf, first_sector, 1, 0, 1);
3897 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
3898 set_bit(STRIPE_HANDLE, &sh->state);
3900 first_sector += STRIPE_SECTORS;
3902 /* Now that the sources are clearly marked, we can release
3903 * the destination stripes
3905 while (!list_empty(&stripes)) {
3906 sh = list_entry(stripes.next, struct stripe_head, lru);
3907 list_del_init(&sh->lru);
3910 /* If this takes us to the resync_max point where we have to pause,
3911 * then we need to write out the superblock.
3913 sector_nr += reshape_sectors;
3914 if ((sector_nr - mddev->curr_resync_completed) * 2
3915 >= mddev->resync_max - mddev->curr_resync_completed) {
3916 /* Cannot proceed until we've updated the superblock... */
3917 wait_event(conf->wait_for_overlap,
3918 atomic_read(&conf->reshape_stripes) == 0);
3919 mddev->reshape_position = conf->reshape_progress;
3920 mddev->curr_resync_completed = sector_nr;
3921 conf->reshape_checkpoint = jiffies;
3922 set_bit(MD_CHANGE_DEVS, &mddev->flags);
3923 md_wakeup_thread(mddev->thread);
3924 wait_event(mddev->sb_wait,
3925 !test_bit(MD_CHANGE_DEVS, &mddev->flags)
3926 || kthread_should_stop());
3927 spin_lock_irq(&conf->device_lock);
3928 conf->reshape_safe = mddev->reshape_position;
3929 spin_unlock_irq(&conf->device_lock);
3930 wake_up(&conf->wait_for_overlap);
3931 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
3933 return reshape_sectors;
3936 /* FIXME go_faster isn't used */
3937 static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
3939 raid5_conf_t *conf = mddev->private;
3940 struct stripe_head *sh;
3941 sector_t max_sector = mddev->dev_sectors;
3942 sector_t sync_blocks;
3943 int still_degraded = 0;
3946 if (sector_nr >= max_sector) {
3947 /* just being told to finish up .. nothing much to do */
3949 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
3954 if (mddev->curr_resync < max_sector) /* aborted */
3955 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
3957 else /* completed sync */
3959 bitmap_close_sync(mddev->bitmap);
3964 /* Allow raid5_quiesce to complete */
3965 wait_event(conf->wait_for_overlap, conf->quiesce != 2);
3967 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3968 return reshape_request(mddev, sector_nr, skipped);
3970 /* No need to check resync_max as we never do more than one
3971 * stripe, and as resync_max will always be on a chunk boundary,
3972 * if the check in md_do_sync didn't fire, there is no chance
3973 * of overstepping resync_max here
3976 /* if there is too many failed drives and we are trying
3977 * to resync, then assert that we are finished, because there is
3978 * nothing we can do.
3980 if (mddev->degraded >= conf->max_degraded &&
3981 test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3982 sector_t rv = mddev->dev_sectors - sector_nr;
3986 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
3987 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
3988 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
3989 /* we can skip this block, and probably more */
3990 sync_blocks /= STRIPE_SECTORS;
3992 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
3996 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
3998 sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
4000 sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
4001 /* make sure we don't swamp the stripe cache if someone else
4002 * is trying to get access
4004 schedule_timeout_uninterruptible(1);
4006 /* Need to check if array will still be degraded after recovery/resync
4007 * We don't need to check the 'failed' flag as when that gets set,
4010 for (i = 0; i < conf->raid_disks; i++)
4011 if (conf->disks[i].rdev == NULL)
4014 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
4016 set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
4021 return STRIPE_SECTORS;
4024 static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
4026 /* We may not be able to submit a whole bio at once as there
4027 * may not be enough stripe_heads available.
4028 * We cannot pre-allocate enough stripe_heads as we may need
4029 * more than exist in the cache (if we allow ever large chunks).
4030 * So we do one stripe head at a time and record in
4031 * ->bi_hw_segments how many have been done.
4033 * We *know* that this entire raid_bio is in one chunk, so
4034 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
4036 struct stripe_head *sh;
4038 sector_t sector, logical_sector, last_sector;
4043 logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
4044 sector = raid5_compute_sector(conf, logical_sector,
4046 last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);
4048 for (; logical_sector < last_sector;
4049 logical_sector += STRIPE_SECTORS,
4050 sector += STRIPE_SECTORS,
4053 if (scnt < raid5_bi_hw_segments(raid_bio))
4054 /* already done this stripe */
4057 sh = get_active_stripe(conf, sector, 0, 1, 0);
4060 /* failed to get a stripe - must wait */
4061 raid5_set_bi_hw_segments(raid_bio, scnt);
4062 conf->retry_read_aligned = raid_bio;
4066 set_bit(R5_ReadError, &sh->dev[dd_idx].flags);
4067 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
4069 raid5_set_bi_hw_segments(raid_bio, scnt);
4070 conf->retry_read_aligned = raid_bio;
4078 spin_lock_irq(&conf->device_lock);
4079 remaining = raid5_dec_bi_phys_segments(raid_bio);
4080 spin_unlock_irq(&conf->device_lock);
4082 bio_endio(raid_bio, 0);
4083 if (atomic_dec_and_test(&conf->active_aligned_reads))
4084 wake_up(&conf->wait_for_stripe);
4090 * This is our raid5 kernel thread.
4092 * We scan the hash table for stripes which can be handled now.
4093 * During the scan, completed stripes are saved for us by the interrupt
4094 * handler, so that they will not have to wait for our next wakeup.
4096 static void raid5d(mddev_t *mddev)
4098 struct stripe_head *sh;
4099 raid5_conf_t *conf = mddev->private;
4101 struct blk_plug plug;
4103 pr_debug("+++ raid5d active\n");
4105 md_check_recovery(mddev);
4107 blk_start_plug(&plug);
4109 spin_lock_irq(&conf->device_lock);
4113 if (atomic_read(&mddev->plug_cnt) == 0 &&
4114 !list_empty(&conf->bitmap_list)) {
4115 /* Now is a good time to flush some bitmap updates */
4117 spin_unlock_irq(&conf->device_lock);
4118 bitmap_unplug(mddev->bitmap);
4119 spin_lock_irq(&conf->device_lock);
4120 conf->seq_write = conf->seq_flush;
4121 activate_bit_delay(conf);
4123 if (atomic_read(&mddev->plug_cnt) == 0)
4124 raid5_activate_delayed(conf);
4126 while ((bio = remove_bio_from_retry(conf))) {
4128 spin_unlock_irq(&conf->device_lock);
4129 ok = retry_aligned_read(conf, bio);
4130 spin_lock_irq(&conf->device_lock);
4136 sh = __get_priority_stripe(conf);
4140 spin_unlock_irq(&conf->device_lock);
4147 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
4148 md_check_recovery(mddev);
4150 spin_lock_irq(&conf->device_lock);
4152 pr_debug("%d stripes handled\n", handled);
4154 spin_unlock_irq(&conf->device_lock);
4156 async_tx_issue_pending_all();
4157 blk_finish_plug(&plug);
4159 pr_debug("--- raid5d inactive\n");
4163 raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
4165 raid5_conf_t *conf = mddev->private;
4167 return sprintf(page, "%d\n", conf->max_nr_stripes);
4173 raid5_set_cache_size(mddev_t *mddev, int size)
4175 raid5_conf_t *conf = mddev->private;
4178 if (size <= 16 || size > 32768)
4180 while (size < conf->max_nr_stripes) {
4181 if (drop_one_stripe(conf))
4182 conf->max_nr_stripes--;
4186 err = md_allow_write(mddev);
4189 while (size > conf->max_nr_stripes) {
4190 if (grow_one_stripe(conf))
4191 conf->max_nr_stripes++;
4196 EXPORT_SYMBOL(raid5_set_cache_size);
4199 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
4201 raid5_conf_t *conf = mddev->private;
4205 if (len >= PAGE_SIZE)
4210 if (strict_strtoul(page, 10, &new))
4212 err = raid5_set_cache_size(mddev, new);
4218 static struct md_sysfs_entry
4219 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
4220 raid5_show_stripe_cache_size,
4221 raid5_store_stripe_cache_size);
4224 raid5_show_preread_threshold(mddev_t *mddev, char *page)
4226 raid5_conf_t *conf = mddev->private;
4228 return sprintf(page, "%d\n", conf->bypass_threshold);
4234 raid5_store_preread_threshold(mddev_t *mddev, const char *page, size_t len)
4236 raid5_conf_t *conf = mddev->private;
4238 if (len >= PAGE_SIZE)
4243 if (strict_strtoul(page, 10, &new))
4245 if (new > conf->max_nr_stripes)
4247 conf->bypass_threshold = new;
4251 static struct md_sysfs_entry
4252 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
4254 raid5_show_preread_threshold,
4255 raid5_store_preread_threshold);
4258 stripe_cache_active_show(mddev_t *mddev, char *page)
4260 raid5_conf_t *conf = mddev->private;
4262 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
4267 static struct md_sysfs_entry
4268 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4270 static struct attribute *raid5_attrs[] = {
4271 &raid5_stripecache_size.attr,
4272 &raid5_stripecache_active.attr,
4273 &raid5_preread_bypass_threshold.attr,
4276 static struct attribute_group raid5_attrs_group = {
4278 .attrs = raid5_attrs,
4282 raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)
4284 raid5_conf_t *conf = mddev->private;
4287 sectors = mddev->dev_sectors;
4289 /* size is defined by the smallest of previous and new size */
4290 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
4292 sectors &= ~((sector_t)mddev->chunk_sectors - 1);
4293 sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
4294 return sectors * (raid_disks - conf->max_degraded);
4297 static void raid5_free_percpu(raid5_conf_t *conf)
4299 struct raid5_percpu *percpu;
4306 for_each_possible_cpu(cpu) {
4307 percpu = per_cpu_ptr(conf->percpu, cpu);
4308 safe_put_page(percpu->spare_page);
4309 kfree(percpu->scribble);
4311 #ifdef CONFIG_HOTPLUG_CPU
4312 unregister_cpu_notifier(&conf->cpu_notify);
4316 free_percpu(conf->percpu);
4319 static void free_conf(raid5_conf_t *conf)
4321 shrink_stripes(conf);
4322 raid5_free_percpu(conf);
4324 kfree(conf->stripe_hashtbl);
4328 #ifdef CONFIG_HOTPLUG_CPU
4329 static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
4332 raid5_conf_t *conf = container_of(nfb, raid5_conf_t, cpu_notify);
4333 long cpu = (long)hcpu;
4334 struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
4337 case CPU_UP_PREPARE:
4338 case CPU_UP_PREPARE_FROZEN:
4339 if (conf->level == 6 && !percpu->spare_page)
4340 percpu->spare_page = alloc_page(GFP_KERNEL);
4341 if (!percpu->scribble)
4342 percpu->scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
4344 if (!percpu->scribble ||
4345 (conf->level == 6 && !percpu->spare_page)) {
4346 safe_put_page(percpu->spare_page);
4347 kfree(percpu->scribble);
4348 pr_err("%s: failed memory allocation for cpu%ld\n",
4350 return notifier_from_errno(-ENOMEM);
4354 case CPU_DEAD_FROZEN:
4355 safe_put_page(percpu->spare_page);
4356 kfree(percpu->scribble);
4357 percpu->spare_page = NULL;
4358 percpu->scribble = NULL;
4367 static int raid5_alloc_percpu(raid5_conf_t *conf)
4370 struct page *spare_page;
4371 struct raid5_percpu __percpu *allcpus;
4375 allcpus = alloc_percpu(struct raid5_percpu);
4378 conf->percpu = allcpus;
4382 for_each_present_cpu(cpu) {
4383 if (conf->level == 6) {
4384 spare_page = alloc_page(GFP_KERNEL);
4389 per_cpu_ptr(conf->percpu, cpu)->spare_page = spare_page;
4391 scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
4396 per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
4398 #ifdef CONFIG_HOTPLUG_CPU
4399 conf->cpu_notify.notifier_call = raid456_cpu_notify;
4400 conf->cpu_notify.priority = 0;
4402 err = register_cpu_notifier(&conf->cpu_notify);
4409 static raid5_conf_t *setup_conf(mddev_t *mddev)
4412 int raid_disk, memory, max_disks;
4414 struct disk_info *disk;
4416 if (mddev->new_level != 5
4417 && mddev->new_level != 4
4418 && mddev->new_level != 6) {
4419 printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
4420 mdname(mddev), mddev->new_level);
4421 return ERR_PTR(-EIO);
4423 if ((mddev->new_level == 5
4424 && !algorithm_valid_raid5(mddev->new_layout)) ||
4425 (mddev->new_level == 6
4426 && !algorithm_valid_raid6(mddev->new_layout))) {
4427 printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
4428 mdname(mddev), mddev->new_layout);
4429 return ERR_PTR(-EIO);
4431 if (mddev->new_level == 6 && mddev->raid_disks < 4) {
4432 printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
4433 mdname(mddev), mddev->raid_disks);
4434 return ERR_PTR(-EINVAL);
4437 if (!mddev->new_chunk_sectors ||
4438 (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
4439 !is_power_of_2(mddev->new_chunk_sectors)) {
4440 printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
4441 mdname(mddev), mddev->new_chunk_sectors << 9);
4442 return ERR_PTR(-EINVAL);
4445 conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL);
4448 spin_lock_init(&conf->device_lock);
4449 init_waitqueue_head(&conf->wait_for_stripe);
4450 init_waitqueue_head(&conf->wait_for_overlap);
4451 INIT_LIST_HEAD(&conf->handle_list);
4452 INIT_LIST_HEAD(&conf->hold_list);
4453 INIT_LIST_HEAD(&conf->delayed_list);
4454 INIT_LIST_HEAD(&conf->bitmap_list);
4455 INIT_LIST_HEAD(&conf->inactive_list);
4456 atomic_set(&conf->active_stripes, 0);
4457 atomic_set(&conf->preread_active_stripes, 0);
4458 atomic_set(&conf->active_aligned_reads, 0);
4459 conf->bypass_threshold = BYPASS_THRESHOLD;
4461 conf->raid_disks = mddev->raid_disks;
4462 if (mddev->reshape_position == MaxSector)
4463 conf->previous_raid_disks = mddev->raid_disks;
4465 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
4466 max_disks = max(conf->raid_disks, conf->previous_raid_disks);
4467 conf->scribble_len = scribble_len(max_disks);
4469 conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
4474 conf->mddev = mddev;
4476 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
4479 conf->level = mddev->new_level;
4480 if (raid5_alloc_percpu(conf) != 0)
4483 pr_debug("raid456: run(%s) called.\n", mdname(mddev));
4485 list_for_each_entry(rdev, &mddev->disks, same_set) {
4486 raid_disk = rdev->raid_disk;
4487 if (raid_disk >= max_disks
4490 disk = conf->disks + raid_disk;
4494 if (test_bit(In_sync, &rdev->flags)) {
4495 char b[BDEVNAME_SIZE];
4496 printk(KERN_INFO "md/raid:%s: device %s operational as raid"
4498 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
4499 } else if (rdev->saved_raid_disk != raid_disk)
4500 /* Cannot rely on bitmap to complete recovery */
4504 conf->chunk_sectors = mddev->new_chunk_sectors;
4505 conf->level = mddev->new_level;
4506 if (conf->level == 6)
4507 conf->max_degraded = 2;
4509 conf->max_degraded = 1;
4510 conf->algorithm = mddev->new_layout;
4511 conf->max_nr_stripes = NR_STRIPES;
4512 conf->reshape_progress = mddev->reshape_position;
4513 if (conf->reshape_progress != MaxSector) {
4514 conf->prev_chunk_sectors = mddev->chunk_sectors;
4515 conf->prev_algo = mddev->layout;
4518 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
4519 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
4520 if (grow_stripes(conf, conf->max_nr_stripes)) {
4522 "md/raid:%s: couldn't allocate %dkB for buffers\n",
4523 mdname(mddev), memory);
4526 printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
4527 mdname(mddev), memory);
4529 conf->thread = md_register_thread(raid5d, mddev, NULL);
4530 if (!conf->thread) {
4532 "md/raid:%s: couldn't allocate thread.\n",
4542 return ERR_PTR(-EIO);
4544 return ERR_PTR(-ENOMEM);
4548 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
4551 case ALGORITHM_PARITY_0:
4552 if (raid_disk < max_degraded)
4555 case ALGORITHM_PARITY_N:
4556 if (raid_disk >= raid_disks - max_degraded)
4559 case ALGORITHM_PARITY_0_6:
4560 if (raid_disk == 0 ||
4561 raid_disk == raid_disks - 1)
4564 case ALGORITHM_LEFT_ASYMMETRIC_6:
4565 case ALGORITHM_RIGHT_ASYMMETRIC_6:
4566 case ALGORITHM_LEFT_SYMMETRIC_6:
4567 case ALGORITHM_RIGHT_SYMMETRIC_6:
4568 if (raid_disk == raid_disks - 1)
4574 static int run(mddev_t *mddev)
4577 int working_disks = 0;
4578 int dirty_parity_disks = 0;
4580 sector_t reshape_offset = 0;
4582 if (mddev->recovery_cp != MaxSector)
4583 printk(KERN_NOTICE "md/raid:%s: not clean"
4584 " -- starting background reconstruction\n",
4586 if (mddev->reshape_position != MaxSector) {
4587 /* Check that we can continue the reshape.
4588 * Currently only disks can change, it must
4589 * increase, and we must be past the point where
4590 * a stripe over-writes itself
4592 sector_t here_new, here_old;
4594 int max_degraded = (mddev->level == 6 ? 2 : 1);
4596 if (mddev->new_level != mddev->level) {
4597 printk(KERN_ERR "md/raid:%s: unsupported reshape "
4598 "required - aborting.\n",
4602 old_disks = mddev->raid_disks - mddev->delta_disks;
4603 /* reshape_position must be on a new-stripe boundary, and one
4604 * further up in new geometry must map after here in old
4607 here_new = mddev->reshape_position;
4608 if (sector_div(here_new, mddev->new_chunk_sectors *
4609 (mddev->raid_disks - max_degraded))) {
4610 printk(KERN_ERR "md/raid:%s: reshape_position not "
4611 "on a stripe boundary\n", mdname(mddev));
4614 reshape_offset = here_new * mddev->new_chunk_sectors;
4615 /* here_new is the stripe we will write to */
4616 here_old = mddev->reshape_position;
4617 sector_div(here_old, mddev->chunk_sectors *
4618 (old_disks-max_degraded));
4619 /* here_old is the first stripe that we might need to read
4621 if (mddev->delta_disks == 0) {
4622 /* We cannot be sure it is safe to start an in-place
4623 * reshape. It is only safe if user-space if monitoring
4624 * and taking constant backups.
4625 * mdadm always starts a situation like this in
4626 * readonly mode so it can take control before
4627 * allowing any writes. So just check for that.
4629 if ((here_new * mddev->new_chunk_sectors !=
4630 here_old * mddev->chunk_sectors) ||
4632 printk(KERN_ERR "md/raid:%s: in-place reshape must be started"
4633 " in read-only mode - aborting\n",
4637 } else if (mddev->delta_disks < 0
4638 ? (here_new * mddev->new_chunk_sectors <=
4639 here_old * mddev->chunk_sectors)
4640 : (here_new * mddev->new_chunk_sectors >=
4641 here_old * mddev->chunk_sectors)) {
4642 /* Reading from the same stripe as writing to - bad */
4643 printk(KERN_ERR "md/raid:%s: reshape_position too early for "
4644 "auto-recovery - aborting.\n",
4648 printk(KERN_INFO "md/raid:%s: reshape will continue\n",
4650 /* OK, we should be able to continue; */
4652 BUG_ON(mddev->level != mddev->new_level);
4653 BUG_ON(mddev->layout != mddev->new_layout);
4654 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
4655 BUG_ON(mddev->delta_disks != 0);
4658 if (mddev->private == NULL)
4659 conf = setup_conf(mddev);
4661 conf = mddev->private;
4664 return PTR_ERR(conf);
4666 mddev->thread = conf->thread;
4667 conf->thread = NULL;
4668 mddev->private = conf;
4671 * 0 for a fully functional array, 1 or 2 for a degraded array.
4673 list_for_each_entry(rdev, &mddev->disks, same_set) {
4674 if (rdev->badblocks.count) {
4675 printk(KERN_ERR "md/raid5: cannot handle bad blocks yet\n");
4678 if (rdev->raid_disk < 0)
4680 if (test_bit(In_sync, &rdev->flags)) {
4684 /* This disc is not fully in-sync. However if it
4685 * just stored parity (beyond the recovery_offset),
4686 * when we don't need to be concerned about the
4687 * array being dirty.
4688 * When reshape goes 'backwards', we never have
4689 * partially completed devices, so we only need
4690 * to worry about reshape going forwards.
4692 /* Hack because v0.91 doesn't store recovery_offset properly. */
4693 if (mddev->major_version == 0 &&
4694 mddev->minor_version > 90)
4695 rdev->recovery_offset = reshape_offset;
4697 if (rdev->recovery_offset < reshape_offset) {
4698 /* We need to check old and new layout */
4699 if (!only_parity(rdev->raid_disk,
4702 conf->max_degraded))
4705 if (!only_parity(rdev->raid_disk,
4707 conf->previous_raid_disks,
4708 conf->max_degraded))
4710 dirty_parity_disks++;
4713 mddev->degraded = (max(conf->raid_disks, conf->previous_raid_disks)
4716 if (has_failed(conf)) {
4717 printk(KERN_ERR "md/raid:%s: not enough operational devices"
4718 " (%d/%d failed)\n",
4719 mdname(mddev), mddev->degraded, conf->raid_disks);
4723 /* device size must be a multiple of chunk size */
4724 mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
4725 mddev->resync_max_sectors = mddev->dev_sectors;
4727 if (mddev->degraded > dirty_parity_disks &&
4728 mddev->recovery_cp != MaxSector) {
4729 if (mddev->ok_start_degraded)
4731 "md/raid:%s: starting dirty degraded array"
4732 " - data corruption possible.\n",
4736 "md/raid:%s: cannot start dirty degraded array.\n",
4742 if (mddev->degraded == 0)
4743 printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
4744 " devices, algorithm %d\n", mdname(mddev), conf->level,
4745 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
4748 printk(KERN_ALERT "md/raid:%s: raid level %d active with %d"
4749 " out of %d devices, algorithm %d\n",
4750 mdname(mddev), conf->level,
4751 mddev->raid_disks - mddev->degraded,
4752 mddev->raid_disks, mddev->new_layout);
4754 print_raid5_conf(conf);
4756 if (conf->reshape_progress != MaxSector) {
4757 conf->reshape_safe = conf->reshape_progress;
4758 atomic_set(&conf->reshape_stripes, 0);
4759 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4760 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4761 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4762 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4763 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4768 /* Ok, everything is just fine now */
4769 if (mddev->to_remove == &raid5_attrs_group)
4770 mddev->to_remove = NULL;
4771 else if (mddev->kobj.sd &&
4772 sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
4774 "raid5: failed to create sysfs attributes for %s\n",
4776 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
4780 /* read-ahead size must cover two whole stripes, which
4781 * is 2 * (datadisks) * chunksize where 'n' is the
4782 * number of raid devices
4784 int data_disks = conf->previous_raid_disks - conf->max_degraded;
4785 int stripe = data_disks *
4786 ((mddev->chunk_sectors << 9) / PAGE_SIZE);
4787 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
4788 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
4790 blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
4792 mddev->queue->backing_dev_info.congested_data = mddev;
4793 mddev->queue->backing_dev_info.congested_fn = raid5_congested;
4795 chunk_size = mddev->chunk_sectors << 9;
4796 blk_queue_io_min(mddev->queue, chunk_size);
4797 blk_queue_io_opt(mddev->queue, chunk_size *
4798 (conf->raid_disks - conf->max_degraded));
4800 list_for_each_entry(rdev, &mddev->disks, same_set)
4801 disk_stack_limits(mddev->gendisk, rdev->bdev,
4802 rdev->data_offset << 9);
4807 md_unregister_thread(mddev->thread);
4808 mddev->thread = NULL;
4810 print_raid5_conf(conf);
4813 mddev->private = NULL;
4814 printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
4818 static int stop(mddev_t *mddev)
4820 raid5_conf_t *conf = mddev->private;
4822 md_unregister_thread(mddev->thread);
4823 mddev->thread = NULL;
4825 mddev->queue->backing_dev_info.congested_fn = NULL;
4827 mddev->private = NULL;
4828 mddev->to_remove = &raid5_attrs_group;
4833 static void print_sh(struct seq_file *seq, struct stripe_head *sh)
4837 seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n",
4838 (unsigned long long)sh->sector, sh->pd_idx, sh->state);
4839 seq_printf(seq, "sh %llu, count %d.\n",
4840 (unsigned long long)sh->sector, atomic_read(&sh->count));
4841 seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector);
4842 for (i = 0; i < sh->disks; i++) {
4843 seq_printf(seq, "(cache%d: %p %ld) ",
4844 i, sh->dev[i].page, sh->dev[i].flags);
4846 seq_printf(seq, "\n");
4849 static void printall(struct seq_file *seq, raid5_conf_t *conf)
4851 struct stripe_head *sh;
4852 struct hlist_node *hn;
4855 spin_lock_irq(&conf->device_lock);
4856 for (i = 0; i < NR_HASH; i++) {
4857 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
4858 if (sh->raid_conf != conf)
4863 spin_unlock_irq(&conf->device_lock);
4867 static void status(struct seq_file *seq, mddev_t *mddev)
4869 raid5_conf_t *conf = mddev->private;
4872 seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
4873 mddev->chunk_sectors / 2, mddev->layout);
4874 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
4875 for (i = 0; i < conf->raid_disks; i++)
4876 seq_printf (seq, "%s",
4877 conf->disks[i].rdev &&
4878 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
4879 seq_printf (seq, "]");
4881 seq_printf (seq, "\n");
4882 printall(seq, conf);
4886 static void print_raid5_conf (raid5_conf_t *conf)
4889 struct disk_info *tmp;
4891 printk(KERN_DEBUG "RAID conf printout:\n");
4893 printk("(conf==NULL)\n");
4896 printk(KERN_DEBUG " --- level:%d rd:%d wd:%d\n", conf->level,
4898 conf->raid_disks - conf->mddev->degraded);
4900 for (i = 0; i < conf->raid_disks; i++) {
4901 char b[BDEVNAME_SIZE];
4902 tmp = conf->disks + i;
4904 printk(KERN_DEBUG " disk %d, o:%d, dev:%s\n",
4905 i, !test_bit(Faulty, &tmp->rdev->flags),
4906 bdevname(tmp->rdev->bdev, b));
4910 static int raid5_spare_active(mddev_t *mddev)
4913 raid5_conf_t *conf = mddev->private;
4914 struct disk_info *tmp;
4916 unsigned long flags;
4918 for (i = 0; i < conf->raid_disks; i++) {
4919 tmp = conf->disks + i;
4921 && tmp->rdev->recovery_offset == MaxSector
4922 && !test_bit(Faulty, &tmp->rdev->flags)
4923 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
4925 sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
4928 spin_lock_irqsave(&conf->device_lock, flags);
4929 mddev->degraded -= count;
4930 spin_unlock_irqrestore(&conf->device_lock, flags);
4931 print_raid5_conf(conf);
4935 static int raid5_remove_disk(mddev_t *mddev, int number)
4937 raid5_conf_t *conf = mddev->private;
4940 struct disk_info *p = conf->disks + number;
4942 print_raid5_conf(conf);
4945 if (number >= conf->raid_disks &&
4946 conf->reshape_progress == MaxSector)
4947 clear_bit(In_sync, &rdev->flags);
4949 if (test_bit(In_sync, &rdev->flags) ||
4950 atomic_read(&rdev->nr_pending)) {
4954 /* Only remove non-faulty devices if recovery
4957 if (!test_bit(Faulty, &rdev->flags) &&
4958 !has_failed(conf) &&
4959 number < conf->raid_disks) {
4965 if (atomic_read(&rdev->nr_pending)) {
4966 /* lost the race, try later */
4973 print_raid5_conf(conf);
4977 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
4979 raid5_conf_t *conf = mddev->private;
4982 struct disk_info *p;
4984 int last = conf->raid_disks - 1;
4986 if (rdev->badblocks.count)
4989 if (has_failed(conf))
4990 /* no point adding a device */
4993 if (rdev->raid_disk >= 0)
4994 first = last = rdev->raid_disk;
4997 * find the disk ... but prefer rdev->saved_raid_disk
5000 if (rdev->saved_raid_disk >= 0 &&
5001 rdev->saved_raid_disk >= first &&
5002 conf->disks[rdev->saved_raid_disk].rdev == NULL)
5003 disk = rdev->saved_raid_disk;
5006 for ( ; disk <= last ; disk++)
5007 if ((p=conf->disks + disk)->rdev == NULL) {
5008 clear_bit(In_sync, &rdev->flags);
5009 rdev->raid_disk = disk;
5011 if (rdev->saved_raid_disk != disk)
5013 rcu_assign_pointer(p->rdev, rdev);
5016 print_raid5_conf(conf);
5020 static int raid5_resize(mddev_t *mddev, sector_t sectors)
5022 /* no resync is happening, and there is enough space
5023 * on all devices, so we can resize.
5024 * We need to make sure resync covers any new space.
5025 * If the array is shrinking we should possibly wait until
5026 * any io in the removed space completes, but it hardly seems
5029 sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5030 md_set_array_sectors(mddev, raid5_size(mddev, sectors,
5031 mddev->raid_disks));
5032 if (mddev->array_sectors >
5033 raid5_size(mddev, sectors, mddev->raid_disks))
5035 set_capacity(mddev->gendisk, mddev->array_sectors);
5036 revalidate_disk(mddev->gendisk);
5037 if (sectors > mddev->dev_sectors &&
5038 mddev->recovery_cp > mddev->dev_sectors) {
5039 mddev->recovery_cp = mddev->dev_sectors;
5040 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5042 mddev->dev_sectors = sectors;
5043 mddev->resync_max_sectors = sectors;
5047 static int check_stripe_cache(mddev_t *mddev)
5049 /* Can only proceed if there are plenty of stripe_heads.
5050 * We need a minimum of one full stripe,, and for sensible progress
5051 * it is best to have about 4 times that.
5052 * If we require 4 times, then the default 256 4K stripe_heads will
5053 * allow for chunk sizes up to 256K, which is probably OK.
5054 * If the chunk size is greater, user-space should request more
5055 * stripe_heads first.
5057 raid5_conf_t *conf = mddev->private;
5058 if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
5059 > conf->max_nr_stripes ||
5060 ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
5061 > conf->max_nr_stripes) {
5062 printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes. Needed %lu\n",
5064 ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
5071 static int check_reshape(mddev_t *mddev)
5073 raid5_conf_t *conf = mddev->private;
5075 if (mddev->delta_disks == 0 &&
5076 mddev->new_layout == mddev->layout &&
5077 mddev->new_chunk_sectors == mddev->chunk_sectors)
5078 return 0; /* nothing to do */
5080 /* Cannot grow a bitmap yet */
5082 if (has_failed(conf))
5084 if (mddev->delta_disks < 0) {
5085 /* We might be able to shrink, but the devices must
5086 * be made bigger first.
5087 * For raid6, 4 is the minimum size.
5088 * Otherwise 2 is the minimum
5091 if (mddev->level == 6)
5093 if (mddev->raid_disks + mddev->delta_disks < min)
5097 if (!check_stripe_cache(mddev))
5100 return resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
5103 static int raid5_start_reshape(mddev_t *mddev)
5105 raid5_conf_t *conf = mddev->private;
5108 unsigned long flags;
5110 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5113 if (!check_stripe_cache(mddev))
5116 list_for_each_entry(rdev, &mddev->disks, same_set)
5117 if (!test_bit(In_sync, &rdev->flags)
5118 && !test_bit(Faulty, &rdev->flags))
5121 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
5122 /* Not enough devices even to make a degraded array
5127 /* Refuse to reduce size of the array. Any reductions in
5128 * array size must be through explicit setting of array_size
5131 if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
5132 < mddev->array_sectors) {
5133 printk(KERN_ERR "md/raid:%s: array size must be reduced "
5134 "before number of disks\n", mdname(mddev));
5138 atomic_set(&conf->reshape_stripes, 0);
5139 spin_lock_irq(&conf->device_lock);
5140 conf->previous_raid_disks = conf->raid_disks;
5141 conf->raid_disks += mddev->delta_disks;
5142 conf->prev_chunk_sectors = conf->chunk_sectors;
5143 conf->chunk_sectors = mddev->new_chunk_sectors;
5144 conf->prev_algo = conf->algorithm;
5145 conf->algorithm = mddev->new_layout;
5146 if (mddev->delta_disks < 0)
5147 conf->reshape_progress = raid5_size(mddev, 0, 0);
5149 conf->reshape_progress = 0;
5150 conf->reshape_safe = conf->reshape_progress;
5152 spin_unlock_irq(&conf->device_lock);
5154 /* Add some new drives, as many as will fit.
5155 * We know there are enough to make the newly sized array work.
5156 * Don't add devices if we are reducing the number of
5157 * devices in the array. This is because it is not possible
5158 * to correctly record the "partially reconstructed" state of
5159 * such devices during the reshape and confusion could result.
5161 if (mddev->delta_disks >= 0) {
5162 int added_devices = 0;
5163 list_for_each_entry(rdev, &mddev->disks, same_set)
5164 if (rdev->raid_disk < 0 &&
5165 !test_bit(Faulty, &rdev->flags)) {
5166 if (raid5_add_disk(mddev, rdev) == 0) {
5168 >= conf->previous_raid_disks) {
5169 set_bit(In_sync, &rdev->flags);
5172 rdev->recovery_offset = 0;
5174 if (sysfs_link_rdev(mddev, rdev))
5175 /* Failure here is OK */;
5177 } else if (rdev->raid_disk >= conf->previous_raid_disks
5178 && !test_bit(Faulty, &rdev->flags)) {
5179 /* This is a spare that was manually added */
5180 set_bit(In_sync, &rdev->flags);
5184 /* When a reshape changes the number of devices,
5185 * ->degraded is measured against the larger of the
5186 * pre and post number of devices.
5188 spin_lock_irqsave(&conf->device_lock, flags);
5189 mddev->degraded += (conf->raid_disks - conf->previous_raid_disks)
5191 spin_unlock_irqrestore(&conf->device_lock, flags);
5193 mddev->raid_disks = conf->raid_disks;
5194 mddev->reshape_position = conf->reshape_progress;
5195 set_bit(MD_CHANGE_DEVS, &mddev->flags);
5197 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
5198 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
5199 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
5200 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
5201 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
5203 if (!mddev->sync_thread) {
5204 mddev->recovery = 0;
5205 spin_lock_irq(&conf->device_lock);
5206 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
5207 conf->reshape_progress = MaxSector;
5208 spin_unlock_irq(&conf->device_lock);
5211 conf->reshape_checkpoint = jiffies;
5212 md_wakeup_thread(mddev->sync_thread);
5213 md_new_event(mddev);
5217 /* This is called from the reshape thread and should make any
5218 * changes needed in 'conf'
5220 static void end_reshape(raid5_conf_t *conf)
5223 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
5225 spin_lock_irq(&conf->device_lock);
5226 conf->previous_raid_disks = conf->raid_disks;
5227 conf->reshape_progress = MaxSector;
5228 spin_unlock_irq(&conf->device_lock);
5229 wake_up(&conf->wait_for_overlap);
5231 /* read-ahead size must cover two whole stripes, which is
5232 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
5234 if (conf->mddev->queue) {
5235 int data_disks = conf->raid_disks - conf->max_degraded;
5236 int stripe = data_disks * ((conf->chunk_sectors << 9)
5238 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
5239 conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
5244 /* This is called from the raid5d thread with mddev_lock held.
5245 * It makes config changes to the device.
5247 static void raid5_finish_reshape(mddev_t *mddev)
5249 raid5_conf_t *conf = mddev->private;
5251 if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
5253 if (mddev->delta_disks > 0) {
5254 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
5255 set_capacity(mddev->gendisk, mddev->array_sectors);
5256 revalidate_disk(mddev->gendisk);
5259 mddev->degraded = conf->raid_disks;
5260 for (d = 0; d < conf->raid_disks ; d++)
5261 if (conf->disks[d].rdev &&
5263 &conf->disks[d].rdev->flags))
5265 for (d = conf->raid_disks ;
5266 d < conf->raid_disks - mddev->delta_disks;
5268 mdk_rdev_t *rdev = conf->disks[d].rdev;
5269 if (rdev && raid5_remove_disk(mddev, d) == 0) {
5270 sysfs_unlink_rdev(mddev, rdev);
5271 rdev->raid_disk = -1;
5275 mddev->layout = conf->algorithm;
5276 mddev->chunk_sectors = conf->chunk_sectors;
5277 mddev->reshape_position = MaxSector;
5278 mddev->delta_disks = 0;
5282 static void raid5_quiesce(mddev_t *mddev, int state)
5284 raid5_conf_t *conf = mddev->private;
5287 case 2: /* resume for a suspend */
5288 wake_up(&conf->wait_for_overlap);
5291 case 1: /* stop all writes */
5292 spin_lock_irq(&conf->device_lock);
5293 /* '2' tells resync/reshape to pause so that all
5294 * active stripes can drain
5297 wait_event_lock_irq(conf->wait_for_stripe,
5298 atomic_read(&conf->active_stripes) == 0 &&
5299 atomic_read(&conf->active_aligned_reads) == 0,
5300 conf->device_lock, /* nothing */);
5302 spin_unlock_irq(&conf->device_lock);
5303 /* allow reshape to continue */
5304 wake_up(&conf->wait_for_overlap);
5307 case 0: /* re-enable writes */
5308 spin_lock_irq(&conf->device_lock);
5310 wake_up(&conf->wait_for_stripe);
5311 wake_up(&conf->wait_for_overlap);
5312 spin_unlock_irq(&conf->device_lock);
5318 static void *raid45_takeover_raid0(mddev_t *mddev, int level)
5320 struct raid0_private_data *raid0_priv = mddev->private;
5323 /* for raid0 takeover only one zone is supported */
5324 if (raid0_priv->nr_strip_zones > 1) {
5325 printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
5327 return ERR_PTR(-EINVAL);
5330 sectors = raid0_priv->strip_zone[0].zone_end;
5331 sector_div(sectors, raid0_priv->strip_zone[0].nb_dev);
5332 mddev->dev_sectors = sectors;
5333 mddev->new_level = level;
5334 mddev->new_layout = ALGORITHM_PARITY_N;
5335 mddev->new_chunk_sectors = mddev->chunk_sectors;
5336 mddev->raid_disks += 1;
5337 mddev->delta_disks = 1;
5338 /* make sure it will be not marked as dirty */
5339 mddev->recovery_cp = MaxSector;
5341 return setup_conf(mddev);
5345 static void *raid5_takeover_raid1(mddev_t *mddev)
5349 if (mddev->raid_disks != 2 ||
5350 mddev->degraded > 1)
5351 return ERR_PTR(-EINVAL);
5353 /* Should check if there are write-behind devices? */
5355 chunksect = 64*2; /* 64K by default */
5357 /* The array must be an exact multiple of chunksize */
5358 while (chunksect && (mddev->array_sectors & (chunksect-1)))
5361 if ((chunksect<<9) < STRIPE_SIZE)
5362 /* array size does not allow a suitable chunk size */
5363 return ERR_PTR(-EINVAL);
5365 mddev->new_level = 5;
5366 mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
5367 mddev->new_chunk_sectors = chunksect;
5369 return setup_conf(mddev);
5372 static void *raid5_takeover_raid6(mddev_t *mddev)
5376 switch (mddev->layout) {
5377 case ALGORITHM_LEFT_ASYMMETRIC_6:
5378 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
5380 case ALGORITHM_RIGHT_ASYMMETRIC_6:
5381 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
5383 case ALGORITHM_LEFT_SYMMETRIC_6:
5384 new_layout = ALGORITHM_LEFT_SYMMETRIC;
5386 case ALGORITHM_RIGHT_SYMMETRIC_6:
5387 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
5389 case ALGORITHM_PARITY_0_6:
5390 new_layout = ALGORITHM_PARITY_0;
5392 case ALGORITHM_PARITY_N:
5393 new_layout = ALGORITHM_PARITY_N;
5396 return ERR_PTR(-EINVAL);
5398 mddev->new_level = 5;
5399 mddev->new_layout = new_layout;
5400 mddev->delta_disks = -1;
5401 mddev->raid_disks -= 1;
5402 return setup_conf(mddev);
5406 static int raid5_check_reshape(mddev_t *mddev)
5408 /* For a 2-drive array, the layout and chunk size can be changed
5409 * immediately as not restriping is needed.
5410 * For larger arrays we record the new value - after validation
5411 * to be used by a reshape pass.
5413 raid5_conf_t *conf = mddev->private;
5414 int new_chunk = mddev->new_chunk_sectors;
5416 if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
5418 if (new_chunk > 0) {
5419 if (!is_power_of_2(new_chunk))
5421 if (new_chunk < (PAGE_SIZE>>9))
5423 if (mddev->array_sectors & (new_chunk-1))
5424 /* not factor of array size */
5428 /* They look valid */
5430 if (mddev->raid_disks == 2) {
5431 /* can make the change immediately */
5432 if (mddev->new_layout >= 0) {
5433 conf->algorithm = mddev->new_layout;
5434 mddev->layout = mddev->new_layout;
5436 if (new_chunk > 0) {
5437 conf->chunk_sectors = new_chunk ;
5438 mddev->chunk_sectors = new_chunk;
5440 set_bit(MD_CHANGE_DEVS, &mddev->flags);
5441 md_wakeup_thread(mddev->thread);
5443 return check_reshape(mddev);
5446 static int raid6_check_reshape(mddev_t *mddev)
5448 int new_chunk = mddev->new_chunk_sectors;
5450 if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
5452 if (new_chunk > 0) {
5453 if (!is_power_of_2(new_chunk))
5455 if (new_chunk < (PAGE_SIZE >> 9))
5457 if (mddev->array_sectors & (new_chunk-1))
5458 /* not factor of array size */
5462 /* They look valid */
5463 return check_reshape(mddev);
5466 static void *raid5_takeover(mddev_t *mddev)
5468 /* raid5 can take over:
5469 * raid0 - if there is only one strip zone - make it a raid4 layout
5470 * raid1 - if there are two drives. We need to know the chunk size
5471 * raid4 - trivial - just use a raid4 layout.
5472 * raid6 - Providing it is a *_6 layout
5474 if (mddev->level == 0)
5475 return raid45_takeover_raid0(mddev, 5);
5476 if (mddev->level == 1)
5477 return raid5_takeover_raid1(mddev);
5478 if (mddev->level == 4) {
5479 mddev->new_layout = ALGORITHM_PARITY_N;
5480 mddev->new_level = 5;
5481 return setup_conf(mddev);
5483 if (mddev->level == 6)
5484 return raid5_takeover_raid6(mddev);
5486 return ERR_PTR(-EINVAL);
5489 static void *raid4_takeover(mddev_t *mddev)
5491 /* raid4 can take over:
5492 * raid0 - if there is only one strip zone
5493 * raid5 - if layout is right
5495 if (mddev->level == 0)
5496 return raid45_takeover_raid0(mddev, 4);
5497 if (mddev->level == 5 &&
5498 mddev->layout == ALGORITHM_PARITY_N) {
5499 mddev->new_layout = 0;
5500 mddev->new_level = 4;
5501 return setup_conf(mddev);
5503 return ERR_PTR(-EINVAL);
5506 static struct mdk_personality raid5_personality;
5508 static void *raid6_takeover(mddev_t *mddev)
5510 /* Currently can only take over a raid5. We map the
5511 * personality to an equivalent raid6 personality
5512 * with the Q block at the end.
5516 if (mddev->pers != &raid5_personality)
5517 return ERR_PTR(-EINVAL);
5518 if (mddev->degraded > 1)
5519 return ERR_PTR(-EINVAL);
5520 if (mddev->raid_disks > 253)
5521 return ERR_PTR(-EINVAL);
5522 if (mddev->raid_disks < 3)
5523 return ERR_PTR(-EINVAL);
5525 switch (mddev->layout) {
5526 case ALGORITHM_LEFT_ASYMMETRIC:
5527 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
5529 case ALGORITHM_RIGHT_ASYMMETRIC:
5530 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
5532 case ALGORITHM_LEFT_SYMMETRIC:
5533 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
5535 case ALGORITHM_RIGHT_SYMMETRIC:
5536 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
5538 case ALGORITHM_PARITY_0:
5539 new_layout = ALGORITHM_PARITY_0_6;
5541 case ALGORITHM_PARITY_N:
5542 new_layout = ALGORITHM_PARITY_N;
5545 return ERR_PTR(-EINVAL);
5547 mddev->new_level = 6;
5548 mddev->new_layout = new_layout;
5549 mddev->delta_disks = 1;
5550 mddev->raid_disks += 1;
5551 return setup_conf(mddev);
5555 static struct mdk_personality raid6_personality =
5559 .owner = THIS_MODULE,
5560 .make_request = make_request,
5564 .error_handler = error,
5565 .hot_add_disk = raid5_add_disk,
5566 .hot_remove_disk= raid5_remove_disk,
5567 .spare_active = raid5_spare_active,
5568 .sync_request = sync_request,
5569 .resize = raid5_resize,
5571 .check_reshape = raid6_check_reshape,
5572 .start_reshape = raid5_start_reshape,
5573 .finish_reshape = raid5_finish_reshape,
5574 .quiesce = raid5_quiesce,
5575 .takeover = raid6_takeover,
5577 static struct mdk_personality raid5_personality =
5581 .owner = THIS_MODULE,
5582 .make_request = make_request,
5586 .error_handler = error,
5587 .hot_add_disk = raid5_add_disk,
5588 .hot_remove_disk= raid5_remove_disk,
5589 .spare_active = raid5_spare_active,
5590 .sync_request = sync_request,
5591 .resize = raid5_resize,
5593 .check_reshape = raid5_check_reshape,
5594 .start_reshape = raid5_start_reshape,
5595 .finish_reshape = raid5_finish_reshape,
5596 .quiesce = raid5_quiesce,
5597 .takeover = raid5_takeover,
5600 static struct mdk_personality raid4_personality =
5604 .owner = THIS_MODULE,
5605 .make_request = make_request,
5609 .error_handler = error,
5610 .hot_add_disk = raid5_add_disk,
5611 .hot_remove_disk= raid5_remove_disk,
5612 .spare_active = raid5_spare_active,
5613 .sync_request = sync_request,
5614 .resize = raid5_resize,
5616 .check_reshape = raid5_check_reshape,
5617 .start_reshape = raid5_start_reshape,
5618 .finish_reshape = raid5_finish_reshape,
5619 .quiesce = raid5_quiesce,
5620 .takeover = raid4_takeover,
5623 static int __init raid5_init(void)
5625 register_md_personality(&raid6_personality);
5626 register_md_personality(&raid5_personality);
5627 register_md_personality(&raid4_personality);
5631 static void raid5_exit(void)
5633 unregister_md_personality(&raid6_personality);
5634 unregister_md_personality(&raid5_personality);
5635 unregister_md_personality(&raid4_personality);
5638 module_init(raid5_init);
5639 module_exit(raid5_exit);
5640 MODULE_LICENSE("GPL");
5641 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
5642 MODULE_ALIAS("md-personality-4"); /* RAID5 */
5643 MODULE_ALIAS("md-raid5");
5644 MODULE_ALIAS("md-raid4");
5645 MODULE_ALIAS("md-level-5");
5646 MODULE_ALIAS("md-level-4");
5647 MODULE_ALIAS("md-personality-8"); /* RAID6 */
5648 MODULE_ALIAS("md-raid6");
5649 MODULE_ALIAS("md-level-6");
5651 /* This used to be two separate modules, they were: */
5652 MODULE_ALIAS("raid5");
5653 MODULE_ALIAS("raid6");