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->bm_write is the number of the last batch successfully written.
31 * conf->bm_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 bm_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/seq_file.h>
59 #define NR_STRIPES 256
60 #define STRIPE_SIZE PAGE_SIZE
61 #define STRIPE_SHIFT (PAGE_SHIFT - 9)
62 #define STRIPE_SECTORS (STRIPE_SIZE>>9)
63 #define IO_THRESHOLD 1
64 #define BYPASS_THRESHOLD 1
65 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
66 #define HASH_MASK (NR_HASH - 1)
68 #define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
70 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
71 * order without overlap. There may be several bio's per stripe+device, and
72 * a bio could span several devices.
73 * When walking this list for a particular stripe+device, we must never proceed
74 * beyond a bio that extends past this device, as the next bio might no longer
76 * This macro is used to determine the 'next' bio in the list, given the sector
77 * of the current stripe+device
79 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
81 * The following can be used to debug the driver
83 #define RAID5_PARANOIA 1
84 #if RAID5_PARANOIA && defined(CONFIG_SMP)
85 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
87 # define CHECK_DEVLOCK()
95 #define printk_rl(args...) ((void) (printk_ratelimit() && printk(args)))
98 * We maintain a biased count of active stripes in the bottom 16 bits of
99 * bi_phys_segments, and a count of processed stripes in the upper 16 bits
101 static inline int raid5_bi_phys_segments(struct bio *bio)
103 return bio->bi_phys_segments & 0xffff;
106 static inline int raid5_bi_hw_segments(struct bio *bio)
108 return (bio->bi_phys_segments >> 16) & 0xffff;
111 static inline int raid5_dec_bi_phys_segments(struct bio *bio)
113 --bio->bi_phys_segments;
114 return raid5_bi_phys_segments(bio);
117 static inline int raid5_dec_bi_hw_segments(struct bio *bio)
119 unsigned short val = raid5_bi_hw_segments(bio);
122 bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio);
126 static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)
128 bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16);
131 /* Find first data disk in a raid6 stripe */
132 static inline int raid6_d0(struct stripe_head *sh)
135 /* ddf always start from first device */
137 /* md starts just after Q block */
138 if (sh->qd_idx == sh->disks - 1)
141 return sh->qd_idx + 1;
143 static inline int raid6_next_disk(int disk, int raid_disks)
146 return (disk < raid_disks) ? disk : 0;
149 /* When walking through the disks in a raid5, starting at raid6_d0,
150 * We need to map each disk to a 'slot', where the data disks are slot
151 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
152 * is raid_disks-1. This help does that mapping.
154 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
155 int *count, int syndrome_disks)
159 if (idx == sh->pd_idx)
160 return syndrome_disks;
161 if (idx == sh->qd_idx)
162 return syndrome_disks + 1;
167 static void return_io(struct bio *return_bi)
169 struct bio *bi = return_bi;
172 return_bi = bi->bi_next;
180 static void print_raid5_conf (raid5_conf_t *conf);
182 static int stripe_operations_active(struct stripe_head *sh)
184 return sh->check_state || sh->reconstruct_state ||
185 test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
186 test_bit(STRIPE_COMPUTE_RUN, &sh->state);
189 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
191 if (atomic_dec_and_test(&sh->count)) {
192 BUG_ON(!list_empty(&sh->lru));
193 BUG_ON(atomic_read(&conf->active_stripes)==0);
194 if (test_bit(STRIPE_HANDLE, &sh->state)) {
195 if (test_bit(STRIPE_DELAYED, &sh->state)) {
196 list_add_tail(&sh->lru, &conf->delayed_list);
197 blk_plug_device(conf->mddev->queue);
198 } else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
199 sh->bm_seq - conf->seq_write > 0) {
200 list_add_tail(&sh->lru, &conf->bitmap_list);
201 blk_plug_device(conf->mddev->queue);
203 clear_bit(STRIPE_BIT_DELAY, &sh->state);
204 list_add_tail(&sh->lru, &conf->handle_list);
206 md_wakeup_thread(conf->mddev->thread);
208 BUG_ON(stripe_operations_active(sh));
209 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
210 atomic_dec(&conf->preread_active_stripes);
211 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
212 md_wakeup_thread(conf->mddev->thread);
214 atomic_dec(&conf->active_stripes);
215 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
216 list_add_tail(&sh->lru, &conf->inactive_list);
217 wake_up(&conf->wait_for_stripe);
218 if (conf->retry_read_aligned)
219 md_wakeup_thread(conf->mddev->thread);
225 static void release_stripe(struct stripe_head *sh)
227 raid5_conf_t *conf = sh->raid_conf;
230 spin_lock_irqsave(&conf->device_lock, flags);
231 __release_stripe(conf, sh);
232 spin_unlock_irqrestore(&conf->device_lock, flags);
235 static inline void remove_hash(struct stripe_head *sh)
237 pr_debug("remove_hash(), stripe %llu\n",
238 (unsigned long long)sh->sector);
240 hlist_del_init(&sh->hash);
243 static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
245 struct hlist_head *hp = stripe_hash(conf, sh->sector);
247 pr_debug("insert_hash(), stripe %llu\n",
248 (unsigned long long)sh->sector);
251 hlist_add_head(&sh->hash, hp);
255 /* find an idle stripe, make sure it is unhashed, and return it. */
256 static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
258 struct stripe_head *sh = NULL;
259 struct list_head *first;
262 if (list_empty(&conf->inactive_list))
264 first = conf->inactive_list.next;
265 sh = list_entry(first, struct stripe_head, lru);
266 list_del_init(first);
268 atomic_inc(&conf->active_stripes);
273 static void shrink_buffers(struct stripe_head *sh, int num)
278 for (i=0; i<num ; i++) {
282 sh->dev[i].page = NULL;
287 static int grow_buffers(struct stripe_head *sh, int num)
291 for (i=0; i<num; i++) {
294 if (!(page = alloc_page(GFP_KERNEL))) {
297 sh->dev[i].page = page;
302 static void raid5_build_block(struct stripe_head *sh, int i, int previous);
303 static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
304 struct stripe_head *sh);
306 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
308 raid5_conf_t *conf = sh->raid_conf;
311 BUG_ON(atomic_read(&sh->count) != 0);
312 BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
313 BUG_ON(stripe_operations_active(sh));
316 pr_debug("init_stripe called, stripe %llu\n",
317 (unsigned long long)sh->sector);
321 sh->generation = conf->generation - previous;
322 sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
324 stripe_set_idx(sector, conf, previous, sh);
328 for (i = sh->disks; i--; ) {
329 struct r5dev *dev = &sh->dev[i];
331 if (dev->toread || dev->read || dev->towrite || dev->written ||
332 test_bit(R5_LOCKED, &dev->flags)) {
333 printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n",
334 (unsigned long long)sh->sector, i, dev->toread,
335 dev->read, dev->towrite, dev->written,
336 test_bit(R5_LOCKED, &dev->flags));
340 raid5_build_block(sh, i, previous);
342 insert_hash(conf, sh);
345 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector,
348 struct stripe_head *sh;
349 struct hlist_node *hn;
352 pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
353 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
354 if (sh->sector == sector && sh->generation == generation)
356 pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
360 static void unplug_slaves(mddev_t *mddev);
361 static void raid5_unplug_device(struct request_queue *q);
363 static struct stripe_head *
364 get_active_stripe(raid5_conf_t *conf, sector_t sector,
365 int previous, int noblock)
367 struct stripe_head *sh;
369 pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
371 spin_lock_irq(&conf->device_lock);
374 wait_event_lock_irq(conf->wait_for_stripe,
376 conf->device_lock, /* nothing */);
377 sh = __find_stripe(conf, sector, conf->generation - previous);
379 if (!conf->inactive_blocked)
380 sh = get_free_stripe(conf);
381 if (noblock && sh == NULL)
384 conf->inactive_blocked = 1;
385 wait_event_lock_irq(conf->wait_for_stripe,
386 !list_empty(&conf->inactive_list) &&
387 (atomic_read(&conf->active_stripes)
388 < (conf->max_nr_stripes *3/4)
389 || !conf->inactive_blocked),
391 raid5_unplug_device(conf->mddev->queue)
393 conf->inactive_blocked = 0;
395 init_stripe(sh, sector, previous);
397 if (atomic_read(&sh->count)) {
398 BUG_ON(!list_empty(&sh->lru)
399 && !test_bit(STRIPE_EXPANDING, &sh->state));
401 if (!test_bit(STRIPE_HANDLE, &sh->state))
402 atomic_inc(&conf->active_stripes);
403 if (list_empty(&sh->lru) &&
404 !test_bit(STRIPE_EXPANDING, &sh->state))
406 list_del_init(&sh->lru);
409 } while (sh == NULL);
412 atomic_inc(&sh->count);
414 spin_unlock_irq(&conf->device_lock);
419 raid5_end_read_request(struct bio *bi, int error);
421 raid5_end_write_request(struct bio *bi, int error);
423 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
425 raid5_conf_t *conf = sh->raid_conf;
426 int i, disks = sh->disks;
430 for (i = disks; i--; ) {
434 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
436 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
441 bi = &sh->dev[i].req;
445 bi->bi_end_io = raid5_end_write_request;
447 bi->bi_end_io = raid5_end_read_request;
450 rdev = rcu_dereference(conf->disks[i].rdev);
451 if (rdev && test_bit(Faulty, &rdev->flags))
454 atomic_inc(&rdev->nr_pending);
458 if (s->syncing || s->expanding || s->expanded)
459 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
461 set_bit(STRIPE_IO_STARTED, &sh->state);
463 bi->bi_bdev = rdev->bdev;
464 pr_debug("%s: for %llu schedule op %ld on disc %d\n",
465 __func__, (unsigned long long)sh->sector,
467 atomic_inc(&sh->count);
468 bi->bi_sector = sh->sector + rdev->data_offset;
469 bi->bi_flags = 1 << BIO_UPTODATE;
473 bi->bi_io_vec = &sh->dev[i].vec;
474 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
475 bi->bi_io_vec[0].bv_offset = 0;
476 bi->bi_size = STRIPE_SIZE;
479 test_bit(R5_ReWrite, &sh->dev[i].flags))
480 atomic_add(STRIPE_SECTORS,
481 &rdev->corrected_errors);
482 generic_make_request(bi);
485 set_bit(STRIPE_DEGRADED, &sh->state);
486 pr_debug("skip op %ld on disc %d for sector %llu\n",
487 bi->bi_rw, i, (unsigned long long)sh->sector);
488 clear_bit(R5_LOCKED, &sh->dev[i].flags);
489 set_bit(STRIPE_HANDLE, &sh->state);
494 static struct dma_async_tx_descriptor *
495 async_copy_data(int frombio, struct bio *bio, struct page *page,
496 sector_t sector, struct dma_async_tx_descriptor *tx)
499 struct page *bio_page;
503 if (bio->bi_sector >= sector)
504 page_offset = (signed)(bio->bi_sector - sector) * 512;
506 page_offset = (signed)(sector - bio->bi_sector) * -512;
507 bio_for_each_segment(bvl, bio, i) {
508 int len = bio_iovec_idx(bio, i)->bv_len;
512 if (page_offset < 0) {
513 b_offset = -page_offset;
514 page_offset += b_offset;
518 if (len > 0 && page_offset + len > STRIPE_SIZE)
519 clen = STRIPE_SIZE - page_offset;
524 b_offset += bio_iovec_idx(bio, i)->bv_offset;
525 bio_page = bio_iovec_idx(bio, i)->bv_page;
527 tx = async_memcpy(page, bio_page, page_offset,
531 tx = async_memcpy(bio_page, page, b_offset,
532 page_offset, clen, 0,
535 if (clen < len) /* hit end of page */
543 static void ops_complete_biofill(void *stripe_head_ref)
545 struct stripe_head *sh = stripe_head_ref;
546 struct bio *return_bi = NULL;
547 raid5_conf_t *conf = sh->raid_conf;
550 pr_debug("%s: stripe %llu\n", __func__,
551 (unsigned long long)sh->sector);
553 /* clear completed biofills */
554 spin_lock_irq(&conf->device_lock);
555 for (i = sh->disks; i--; ) {
556 struct r5dev *dev = &sh->dev[i];
558 /* acknowledge completion of a biofill operation */
559 /* and check if we need to reply to a read request,
560 * new R5_Wantfill requests are held off until
561 * !STRIPE_BIOFILL_RUN
563 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
564 struct bio *rbi, *rbi2;
569 while (rbi && rbi->bi_sector <
570 dev->sector + STRIPE_SECTORS) {
571 rbi2 = r5_next_bio(rbi, dev->sector);
572 if (!raid5_dec_bi_phys_segments(rbi)) {
573 rbi->bi_next = return_bi;
580 spin_unlock_irq(&conf->device_lock);
581 clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
583 return_io(return_bi);
585 set_bit(STRIPE_HANDLE, &sh->state);
589 static void ops_run_biofill(struct stripe_head *sh)
591 struct dma_async_tx_descriptor *tx = NULL;
592 raid5_conf_t *conf = sh->raid_conf;
595 pr_debug("%s: stripe %llu\n", __func__,
596 (unsigned long long)sh->sector);
598 for (i = sh->disks; i--; ) {
599 struct r5dev *dev = &sh->dev[i];
600 if (test_bit(R5_Wantfill, &dev->flags)) {
602 spin_lock_irq(&conf->device_lock);
603 dev->read = rbi = dev->toread;
605 spin_unlock_irq(&conf->device_lock);
606 while (rbi && rbi->bi_sector <
607 dev->sector + STRIPE_SECTORS) {
608 tx = async_copy_data(0, rbi, dev->page,
610 rbi = r5_next_bio(rbi, dev->sector);
615 atomic_inc(&sh->count);
616 async_trigger_callback(ASYNC_TX_ACK, tx, ops_complete_biofill, sh);
619 static void ops_complete_compute5(void *stripe_head_ref)
621 struct stripe_head *sh = stripe_head_ref;
622 int target = sh->ops.target;
623 struct r5dev *tgt = &sh->dev[target];
625 pr_debug("%s: stripe %llu\n", __func__,
626 (unsigned long long)sh->sector);
628 set_bit(R5_UPTODATE, &tgt->flags);
629 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
630 clear_bit(R5_Wantcompute, &tgt->flags);
631 clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
632 if (sh->check_state == check_state_compute_run)
633 sh->check_state = check_state_compute_result;
634 set_bit(STRIPE_HANDLE, &sh->state);
638 static struct dma_async_tx_descriptor *ops_run_compute5(struct stripe_head *sh)
640 /* kernel stack size limits the total number of disks */
641 int disks = sh->disks;
642 struct page *xor_srcs[disks];
643 int target = sh->ops.target;
644 struct r5dev *tgt = &sh->dev[target];
645 struct page *xor_dest = tgt->page;
647 struct dma_async_tx_descriptor *tx;
650 pr_debug("%s: stripe %llu block: %d\n",
651 __func__, (unsigned long long)sh->sector, target);
652 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
654 for (i = disks; i--; )
656 xor_srcs[count++] = sh->dev[i].page;
658 atomic_inc(&sh->count);
660 if (unlikely(count == 1))
661 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
662 0, NULL, ops_complete_compute5, sh);
664 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
665 ASYNC_TX_XOR_ZERO_DST, NULL,
666 ops_complete_compute5, sh);
671 static void ops_complete_prexor(void *stripe_head_ref)
673 struct stripe_head *sh = stripe_head_ref;
675 pr_debug("%s: stripe %llu\n", __func__,
676 (unsigned long long)sh->sector);
679 static struct dma_async_tx_descriptor *
680 ops_run_prexor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
682 /* kernel stack size limits the total number of disks */
683 int disks = sh->disks;
684 struct page *xor_srcs[disks];
685 int count = 0, pd_idx = sh->pd_idx, i;
687 /* existing parity data subtracted */
688 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
690 pr_debug("%s: stripe %llu\n", __func__,
691 (unsigned long long)sh->sector);
693 for (i = disks; i--; ) {
694 struct r5dev *dev = &sh->dev[i];
695 /* Only process blocks that are known to be uptodate */
696 if (test_bit(R5_Wantdrain, &dev->flags))
697 xor_srcs[count++] = dev->page;
700 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
701 ASYNC_TX_XOR_DROP_DST, tx,
702 ops_complete_prexor, sh);
707 static struct dma_async_tx_descriptor *
708 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
710 int disks = sh->disks;
713 pr_debug("%s: stripe %llu\n", __func__,
714 (unsigned long long)sh->sector);
716 for (i = disks; i--; ) {
717 struct r5dev *dev = &sh->dev[i];
720 if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
723 spin_lock(&sh->lock);
724 chosen = dev->towrite;
726 BUG_ON(dev->written);
727 wbi = dev->written = chosen;
728 spin_unlock(&sh->lock);
730 while (wbi && wbi->bi_sector <
731 dev->sector + STRIPE_SECTORS) {
732 tx = async_copy_data(1, wbi, dev->page,
734 wbi = r5_next_bio(wbi, dev->sector);
742 static void ops_complete_postxor(void *stripe_head_ref)
744 struct stripe_head *sh = stripe_head_ref;
745 int disks = sh->disks, i, pd_idx = sh->pd_idx;
747 pr_debug("%s: stripe %llu\n", __func__,
748 (unsigned long long)sh->sector);
750 for (i = disks; i--; ) {
751 struct r5dev *dev = &sh->dev[i];
752 if (dev->written || i == pd_idx)
753 set_bit(R5_UPTODATE, &dev->flags);
756 if (sh->reconstruct_state == reconstruct_state_drain_run)
757 sh->reconstruct_state = reconstruct_state_drain_result;
758 else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
759 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
761 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
762 sh->reconstruct_state = reconstruct_state_result;
765 set_bit(STRIPE_HANDLE, &sh->state);
770 ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
772 /* kernel stack size limits the total number of disks */
773 int disks = sh->disks;
774 struct page *xor_srcs[disks];
776 int count = 0, pd_idx = sh->pd_idx, i;
777 struct page *xor_dest;
781 pr_debug("%s: stripe %llu\n", __func__,
782 (unsigned long long)sh->sector);
784 /* check if prexor is active which means only process blocks
785 * that are part of a read-modify-write (written)
787 if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
789 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
790 for (i = disks; i--; ) {
791 struct r5dev *dev = &sh->dev[i];
793 xor_srcs[count++] = dev->page;
796 xor_dest = sh->dev[pd_idx].page;
797 for (i = disks; i--; ) {
798 struct r5dev *dev = &sh->dev[i];
800 xor_srcs[count++] = dev->page;
804 /* 1/ if we prexor'd then the dest is reused as a source
805 * 2/ if we did not prexor then we are redoing the parity
806 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
807 * for the synchronous xor case
809 flags = ASYNC_TX_ACK |
810 (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
812 atomic_inc(&sh->count);
814 if (unlikely(count == 1)) {
815 flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST);
816 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
817 flags, tx, ops_complete_postxor, sh);
819 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
820 flags, tx, ops_complete_postxor, sh);
823 static void ops_complete_check(void *stripe_head_ref)
825 struct stripe_head *sh = stripe_head_ref;
827 pr_debug("%s: stripe %llu\n", __func__,
828 (unsigned long long)sh->sector);
830 sh->check_state = check_state_check_result;
831 set_bit(STRIPE_HANDLE, &sh->state);
835 static void ops_run_check(struct stripe_head *sh)
837 /* kernel stack size limits the total number of disks */
838 int disks = sh->disks;
839 struct page *xor_srcs[disks];
840 struct dma_async_tx_descriptor *tx;
842 int count = 0, pd_idx = sh->pd_idx, i;
843 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
845 pr_debug("%s: stripe %llu\n", __func__,
846 (unsigned long long)sh->sector);
848 for (i = disks; i--; ) {
849 struct r5dev *dev = &sh->dev[i];
851 xor_srcs[count++] = dev->page;
854 tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
855 &sh->ops.zero_sum_result, 0, NULL, NULL, NULL);
857 atomic_inc(&sh->count);
858 tx = async_trigger_callback(ASYNC_TX_ACK, tx,
859 ops_complete_check, sh);
862 static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request)
864 int overlap_clear = 0, i, disks = sh->disks;
865 struct dma_async_tx_descriptor *tx = NULL;
867 if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
872 if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
873 tx = ops_run_compute5(sh);
874 /* terminate the chain if postxor is not set to be run */
875 if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
879 if (test_bit(STRIPE_OP_PREXOR, &ops_request))
880 tx = ops_run_prexor(sh, tx);
882 if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
883 tx = ops_run_biodrain(sh, tx);
887 if (test_bit(STRIPE_OP_POSTXOR, &ops_request))
888 ops_run_postxor(sh, tx);
890 if (test_bit(STRIPE_OP_CHECK, &ops_request))
894 for (i = disks; i--; ) {
895 struct r5dev *dev = &sh->dev[i];
896 if (test_and_clear_bit(R5_Overlap, &dev->flags))
897 wake_up(&sh->raid_conf->wait_for_overlap);
901 static int grow_one_stripe(raid5_conf_t *conf)
903 struct stripe_head *sh;
904 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL);
907 memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
908 sh->raid_conf = conf;
909 spin_lock_init(&sh->lock);
911 if (grow_buffers(sh, conf->raid_disks)) {
912 shrink_buffers(sh, conf->raid_disks);
913 kmem_cache_free(conf->slab_cache, sh);
916 sh->disks = conf->raid_disks;
917 /* we just created an active stripe so... */
918 atomic_set(&sh->count, 1);
919 atomic_inc(&conf->active_stripes);
920 INIT_LIST_HEAD(&sh->lru);
925 static int grow_stripes(raid5_conf_t *conf, int num)
927 struct kmem_cache *sc;
928 int devs = conf->raid_disks;
930 sprintf(conf->cache_name[0],
931 "raid%d-%s", conf->level, mdname(conf->mddev));
932 sprintf(conf->cache_name[1],
933 "raid%d-%s-alt", conf->level, mdname(conf->mddev));
934 conf->active_name = 0;
935 sc = kmem_cache_create(conf->cache_name[conf->active_name],
936 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
940 conf->slab_cache = sc;
941 conf->pool_size = devs;
943 if (!grow_one_stripe(conf))
948 static int resize_stripes(raid5_conf_t *conf, int newsize)
950 /* Make all the stripes able to hold 'newsize' devices.
951 * New slots in each stripe get 'page' set to a new page.
953 * This happens in stages:
954 * 1/ create a new kmem_cache and allocate the required number of
956 * 2/ gather all the old stripe_heads and tranfer the pages across
957 * to the new stripe_heads. This will have the side effect of
958 * freezing the array as once all stripe_heads have been collected,
959 * no IO will be possible. Old stripe heads are freed once their
960 * pages have been transferred over, and the old kmem_cache is
961 * freed when all stripes are done.
962 * 3/ reallocate conf->disks to be suitable bigger. If this fails,
963 * we simple return a failre status - no need to clean anything up.
964 * 4/ allocate new pages for the new slots in the new stripe_heads.
965 * If this fails, we don't bother trying the shrink the
966 * stripe_heads down again, we just leave them as they are.
967 * As each stripe_head is processed the new one is released into
970 * Once step2 is started, we cannot afford to wait for a write,
971 * so we use GFP_NOIO allocations.
973 struct stripe_head *osh, *nsh;
974 LIST_HEAD(newstripes);
975 struct disk_info *ndisks;
977 struct kmem_cache *sc;
980 if (newsize <= conf->pool_size)
981 return 0; /* never bother to shrink */
983 err = md_allow_write(conf->mddev);
988 sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
989 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
994 for (i = conf->max_nr_stripes; i; i--) {
995 nsh = kmem_cache_alloc(sc, GFP_KERNEL);
999 memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev));
1001 nsh->raid_conf = conf;
1002 spin_lock_init(&nsh->lock);
1004 list_add(&nsh->lru, &newstripes);
1007 /* didn't get enough, give up */
1008 while (!list_empty(&newstripes)) {
1009 nsh = list_entry(newstripes.next, struct stripe_head, lru);
1010 list_del(&nsh->lru);
1011 kmem_cache_free(sc, nsh);
1013 kmem_cache_destroy(sc);
1016 /* Step 2 - Must use GFP_NOIO now.
1017 * OK, we have enough stripes, start collecting inactive
1018 * stripes and copying them over
1020 list_for_each_entry(nsh, &newstripes, lru) {
1021 spin_lock_irq(&conf->device_lock);
1022 wait_event_lock_irq(conf->wait_for_stripe,
1023 !list_empty(&conf->inactive_list),
1025 unplug_slaves(conf->mddev)
1027 osh = get_free_stripe(conf);
1028 spin_unlock_irq(&conf->device_lock);
1029 atomic_set(&nsh->count, 1);
1030 for(i=0; i<conf->pool_size; i++)
1031 nsh->dev[i].page = osh->dev[i].page;
1032 for( ; i<newsize; i++)
1033 nsh->dev[i].page = NULL;
1034 kmem_cache_free(conf->slab_cache, osh);
1036 kmem_cache_destroy(conf->slab_cache);
1039 * At this point, we are holding all the stripes so the array
1040 * is completely stalled, so now is a good time to resize
1043 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
1045 for (i=0; i<conf->raid_disks; i++)
1046 ndisks[i] = conf->disks[i];
1048 conf->disks = ndisks;
1052 /* Step 4, return new stripes to service */
1053 while(!list_empty(&newstripes)) {
1054 nsh = list_entry(newstripes.next, struct stripe_head, lru);
1055 list_del_init(&nsh->lru);
1056 for (i=conf->raid_disks; i < newsize; i++)
1057 if (nsh->dev[i].page == NULL) {
1058 struct page *p = alloc_page(GFP_NOIO);
1059 nsh->dev[i].page = p;
1063 release_stripe(nsh);
1065 /* critical section pass, GFP_NOIO no longer needed */
1067 conf->slab_cache = sc;
1068 conf->active_name = 1-conf->active_name;
1069 conf->pool_size = newsize;
1073 static int drop_one_stripe(raid5_conf_t *conf)
1075 struct stripe_head *sh;
1077 spin_lock_irq(&conf->device_lock);
1078 sh = get_free_stripe(conf);
1079 spin_unlock_irq(&conf->device_lock);
1082 BUG_ON(atomic_read(&sh->count));
1083 shrink_buffers(sh, conf->pool_size);
1084 kmem_cache_free(conf->slab_cache, sh);
1085 atomic_dec(&conf->active_stripes);
1089 static void shrink_stripes(raid5_conf_t *conf)
1091 while (drop_one_stripe(conf))
1094 if (conf->slab_cache)
1095 kmem_cache_destroy(conf->slab_cache);
1096 conf->slab_cache = NULL;
1099 static void raid5_end_read_request(struct bio * bi, int error)
1101 struct stripe_head *sh = bi->bi_private;
1102 raid5_conf_t *conf = sh->raid_conf;
1103 int disks = sh->disks, i;
1104 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1105 char b[BDEVNAME_SIZE];
1109 for (i=0 ; i<disks; i++)
1110 if (bi == &sh->dev[i].req)
1113 pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
1114 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
1122 set_bit(R5_UPTODATE, &sh->dev[i].flags);
1123 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1124 rdev = conf->disks[i].rdev;
1125 printk_rl(KERN_INFO "raid5:%s: read error corrected"
1126 " (%lu sectors at %llu on %s)\n",
1127 mdname(conf->mddev), STRIPE_SECTORS,
1128 (unsigned long long)(sh->sector
1129 + rdev->data_offset),
1130 bdevname(rdev->bdev, b));
1131 clear_bit(R5_ReadError, &sh->dev[i].flags);
1132 clear_bit(R5_ReWrite, &sh->dev[i].flags);
1134 if (atomic_read(&conf->disks[i].rdev->read_errors))
1135 atomic_set(&conf->disks[i].rdev->read_errors, 0);
1137 const char *bdn = bdevname(conf->disks[i].rdev->bdev, b);
1139 rdev = conf->disks[i].rdev;
1141 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1142 atomic_inc(&rdev->read_errors);
1143 if (conf->mddev->degraded)
1144 printk_rl(KERN_WARNING
1145 "raid5:%s: read error not correctable "
1146 "(sector %llu on %s).\n",
1147 mdname(conf->mddev),
1148 (unsigned long long)(sh->sector
1149 + rdev->data_offset),
1151 else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
1153 printk_rl(KERN_WARNING
1154 "raid5:%s: read error NOT corrected!! "
1155 "(sector %llu on %s).\n",
1156 mdname(conf->mddev),
1157 (unsigned long long)(sh->sector
1158 + rdev->data_offset),
1160 else if (atomic_read(&rdev->read_errors)
1161 > conf->max_nr_stripes)
1163 "raid5:%s: Too many read errors, failing device %s.\n",
1164 mdname(conf->mddev), bdn);
1168 set_bit(R5_ReadError, &sh->dev[i].flags);
1170 clear_bit(R5_ReadError, &sh->dev[i].flags);
1171 clear_bit(R5_ReWrite, &sh->dev[i].flags);
1172 md_error(conf->mddev, rdev);
1175 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
1176 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1177 set_bit(STRIPE_HANDLE, &sh->state);
1181 static void raid5_end_write_request(struct bio *bi, int error)
1183 struct stripe_head *sh = bi->bi_private;
1184 raid5_conf_t *conf = sh->raid_conf;
1185 int disks = sh->disks, i;
1186 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1188 for (i=0 ; i<disks; i++)
1189 if (bi == &sh->dev[i].req)
1192 pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
1193 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
1201 md_error(conf->mddev, conf->disks[i].rdev);
1203 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
1205 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1206 set_bit(STRIPE_HANDLE, &sh->state);
1211 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
1213 static void raid5_build_block(struct stripe_head *sh, int i, int previous)
1215 struct r5dev *dev = &sh->dev[i];
1217 bio_init(&dev->req);
1218 dev->req.bi_io_vec = &dev->vec;
1220 dev->req.bi_max_vecs++;
1221 dev->vec.bv_page = dev->page;
1222 dev->vec.bv_len = STRIPE_SIZE;
1223 dev->vec.bv_offset = 0;
1225 dev->req.bi_sector = sh->sector;
1226 dev->req.bi_private = sh;
1229 dev->sector = compute_blocknr(sh, i, previous);
1232 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1234 char b[BDEVNAME_SIZE];
1235 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1236 pr_debug("raid5: error called\n");
1238 if (!test_bit(Faulty, &rdev->flags)) {
1239 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1240 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1241 unsigned long flags;
1242 spin_lock_irqsave(&conf->device_lock, flags);
1244 spin_unlock_irqrestore(&conf->device_lock, flags);
1246 * if recovery was running, make sure it aborts.
1248 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1250 set_bit(Faulty, &rdev->flags);
1252 "raid5: Disk failure on %s, disabling device.\n"
1253 "raid5: Operation continuing on %d devices.\n",
1254 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
1259 * Input: a 'big' sector number,
1260 * Output: index of the data and parity disk, and the sector # in them.
1262 static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector,
1263 int previous, int *dd_idx,
1264 struct stripe_head *sh)
1267 unsigned long chunk_number;
1268 unsigned int chunk_offset;
1271 sector_t new_sector;
1272 int algorithm = previous ? conf->prev_algo
1274 int sectors_per_chunk = previous ? (conf->prev_chunk >> 9)
1275 : (conf->chunk_size >> 9);
1276 int raid_disks = previous ? conf->previous_raid_disks
1278 int data_disks = raid_disks - conf->max_degraded;
1280 /* First compute the information on this sector */
1283 * Compute the chunk number and the sector offset inside the chunk
1285 chunk_offset = sector_div(r_sector, sectors_per_chunk);
1286 chunk_number = r_sector;
1287 BUG_ON(r_sector != chunk_number);
1290 * Compute the stripe number
1292 stripe = chunk_number / data_disks;
1295 * Compute the data disk and parity disk indexes inside the stripe
1297 *dd_idx = chunk_number % data_disks;
1300 * Select the parity disk based on the user selected algorithm.
1302 pd_idx = qd_idx = ~0;
1303 switch(conf->level) {
1305 pd_idx = data_disks;
1308 switch (algorithm) {
1309 case ALGORITHM_LEFT_ASYMMETRIC:
1310 pd_idx = data_disks - stripe % raid_disks;
1311 if (*dd_idx >= pd_idx)
1314 case ALGORITHM_RIGHT_ASYMMETRIC:
1315 pd_idx = stripe % raid_disks;
1316 if (*dd_idx >= pd_idx)
1319 case ALGORITHM_LEFT_SYMMETRIC:
1320 pd_idx = data_disks - stripe % raid_disks;
1321 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
1323 case ALGORITHM_RIGHT_SYMMETRIC:
1324 pd_idx = stripe % raid_disks;
1325 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
1327 case ALGORITHM_PARITY_0:
1331 case ALGORITHM_PARITY_N:
1332 pd_idx = data_disks;
1335 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
1342 switch (algorithm) {
1343 case ALGORITHM_LEFT_ASYMMETRIC:
1344 pd_idx = raid_disks - 1 - (stripe % raid_disks);
1345 qd_idx = pd_idx + 1;
1346 if (pd_idx == raid_disks-1) {
1347 (*dd_idx)++; /* Q D D D P */
1349 } else if (*dd_idx >= pd_idx)
1350 (*dd_idx) += 2; /* D D P Q D */
1352 case ALGORITHM_RIGHT_ASYMMETRIC:
1353 pd_idx = stripe % raid_disks;
1354 qd_idx = pd_idx + 1;
1355 if (pd_idx == raid_disks-1) {
1356 (*dd_idx)++; /* Q D D D P */
1358 } else if (*dd_idx >= pd_idx)
1359 (*dd_idx) += 2; /* D D P Q D */
1361 case ALGORITHM_LEFT_SYMMETRIC:
1362 pd_idx = raid_disks - 1 - (stripe % raid_disks);
1363 qd_idx = (pd_idx + 1) % raid_disks;
1364 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
1366 case ALGORITHM_RIGHT_SYMMETRIC:
1367 pd_idx = stripe % raid_disks;
1368 qd_idx = (pd_idx + 1) % raid_disks;
1369 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
1372 case ALGORITHM_PARITY_0:
1377 case ALGORITHM_PARITY_N:
1378 pd_idx = data_disks;
1379 qd_idx = data_disks + 1;
1382 case ALGORITHM_ROTATING_ZERO_RESTART:
1383 /* Exactly the same as RIGHT_ASYMMETRIC, but or
1384 * of blocks for computing Q is different.
1386 pd_idx = stripe % raid_disks;
1387 qd_idx = pd_idx + 1;
1388 if (pd_idx == raid_disks-1) {
1389 (*dd_idx)++; /* Q D D D P */
1391 } else if (*dd_idx >= pd_idx)
1392 (*dd_idx) += 2; /* D D P Q D */
1396 case ALGORITHM_ROTATING_N_RESTART:
1397 /* Same a left_asymmetric, by first stripe is
1398 * D D D P Q rather than
1401 pd_idx = raid_disks - 1 - ((stripe + 1) % raid_disks);
1402 qd_idx = pd_idx + 1;
1403 if (pd_idx == raid_disks-1) {
1404 (*dd_idx)++; /* Q D D D P */
1406 } else if (*dd_idx >= pd_idx)
1407 (*dd_idx) += 2; /* D D P Q D */
1411 case ALGORITHM_ROTATING_N_CONTINUE:
1412 /* Same as left_symmetric but Q is before P */
1413 pd_idx = raid_disks - 1 - (stripe % raid_disks);
1414 qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
1415 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
1419 case ALGORITHM_LEFT_ASYMMETRIC_6:
1420 /* RAID5 left_asymmetric, with Q on last device */
1421 pd_idx = data_disks - stripe % (raid_disks-1);
1422 if (*dd_idx >= pd_idx)
1424 qd_idx = raid_disks - 1;
1427 case ALGORITHM_RIGHT_ASYMMETRIC_6:
1428 pd_idx = stripe % (raid_disks-1);
1429 if (*dd_idx >= pd_idx)
1431 qd_idx = raid_disks - 1;
1434 case ALGORITHM_LEFT_SYMMETRIC_6:
1435 pd_idx = data_disks - stripe % (raid_disks-1);
1436 *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
1437 qd_idx = raid_disks - 1;
1440 case ALGORITHM_RIGHT_SYMMETRIC_6:
1441 pd_idx = stripe % (raid_disks-1);
1442 *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
1443 qd_idx = raid_disks - 1;
1446 case ALGORITHM_PARITY_0_6:
1449 qd_idx = raid_disks - 1;
1454 printk(KERN_CRIT "raid6: unsupported algorithm %d\n",
1462 sh->pd_idx = pd_idx;
1463 sh->qd_idx = qd_idx;
1464 sh->ddf_layout = ddf_layout;
1467 * Finally, compute the new sector number
1469 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
1474 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
1476 raid5_conf_t *conf = sh->raid_conf;
1477 int raid_disks = sh->disks;
1478 int data_disks = raid_disks - conf->max_degraded;
1479 sector_t new_sector = sh->sector, check;
1480 int sectors_per_chunk = previous ? (conf->prev_chunk >> 9)
1481 : (conf->chunk_size >> 9);
1482 int algorithm = previous ? conf->prev_algo
1486 int chunk_number, dummy1, dd_idx = i;
1488 struct stripe_head sh2;
1491 chunk_offset = sector_div(new_sector, sectors_per_chunk);
1492 stripe = new_sector;
1493 BUG_ON(new_sector != stripe);
1495 if (i == sh->pd_idx)
1497 switch(conf->level) {
1500 switch (algorithm) {
1501 case ALGORITHM_LEFT_ASYMMETRIC:
1502 case ALGORITHM_RIGHT_ASYMMETRIC:
1506 case ALGORITHM_LEFT_SYMMETRIC:
1507 case ALGORITHM_RIGHT_SYMMETRIC:
1510 i -= (sh->pd_idx + 1);
1512 case ALGORITHM_PARITY_0:
1515 case ALGORITHM_PARITY_N:
1518 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
1524 if (i == sh->qd_idx)
1525 return 0; /* It is the Q disk */
1526 switch (algorithm) {
1527 case ALGORITHM_LEFT_ASYMMETRIC:
1528 case ALGORITHM_RIGHT_ASYMMETRIC:
1529 case ALGORITHM_ROTATING_ZERO_RESTART:
1530 case ALGORITHM_ROTATING_N_RESTART:
1531 if (sh->pd_idx == raid_disks-1)
1532 i--; /* Q D D D P */
1533 else if (i > sh->pd_idx)
1534 i -= 2; /* D D P Q D */
1536 case ALGORITHM_LEFT_SYMMETRIC:
1537 case ALGORITHM_RIGHT_SYMMETRIC:
1538 if (sh->pd_idx == raid_disks-1)
1539 i--; /* Q D D D P */
1544 i -= (sh->pd_idx + 2);
1547 case ALGORITHM_PARITY_0:
1550 case ALGORITHM_PARITY_N:
1552 case ALGORITHM_ROTATING_N_CONTINUE:
1553 if (sh->pd_idx == 0)
1554 i--; /* P D D D Q */
1555 else if (i > sh->pd_idx)
1556 i -= 2; /* D D Q P D */
1558 case ALGORITHM_LEFT_ASYMMETRIC_6:
1559 case ALGORITHM_RIGHT_ASYMMETRIC_6:
1563 case ALGORITHM_LEFT_SYMMETRIC_6:
1564 case ALGORITHM_RIGHT_SYMMETRIC_6:
1566 i += data_disks + 1;
1567 i -= (sh->pd_idx + 1);
1569 case ALGORITHM_PARITY_0_6:
1573 printk(KERN_CRIT "raid6: unsupported algorithm %d\n",
1580 chunk_number = stripe * data_disks + i;
1581 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
1583 check = raid5_compute_sector(conf, r_sector,
1584 previous, &dummy1, &sh2);
1585 if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
1586 || sh2.qd_idx != sh->qd_idx) {
1587 printk(KERN_ERR "compute_blocknr: map not correct\n");
1596 * Copy data between a page in the stripe cache, and one or more bion
1597 * The page could align with the middle of the bio, or there could be
1598 * several bion, each with several bio_vecs, which cover part of the page
1599 * Multiple bion are linked together on bi_next. There may be extras
1600 * at the end of this list. We ignore them.
1602 static void copy_data(int frombio, struct bio *bio,
1606 char *pa = page_address(page);
1607 struct bio_vec *bvl;
1611 if (bio->bi_sector >= sector)
1612 page_offset = (signed)(bio->bi_sector - sector) * 512;
1614 page_offset = (signed)(sector - bio->bi_sector) * -512;
1615 bio_for_each_segment(bvl, bio, i) {
1616 int len = bio_iovec_idx(bio,i)->bv_len;
1620 if (page_offset < 0) {
1621 b_offset = -page_offset;
1622 page_offset += b_offset;
1626 if (len > 0 && page_offset + len > STRIPE_SIZE)
1627 clen = STRIPE_SIZE - page_offset;
1631 char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
1633 memcpy(pa+page_offset, ba+b_offset, clen);
1635 memcpy(ba+b_offset, pa+page_offset, clen);
1636 __bio_kunmap_atomic(ba, KM_USER0);
1638 if (clen < len) /* hit end of page */
1644 #define check_xor() do { \
1645 if (count == MAX_XOR_BLOCKS) { \
1646 xor_blocks(count, STRIPE_SIZE, dest, ptr);\
1651 static void compute_parity6(struct stripe_head *sh, int method)
1653 raid5_conf_t *conf = sh->raid_conf;
1654 int i, pd_idx, qd_idx, d0_idx, disks = sh->disks, count;
1655 int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1657 /**** FIX THIS: This could be very bad if disks is close to 256 ****/
1658 void *ptrs[syndrome_disks+2];
1660 pd_idx = sh->pd_idx;
1661 qd_idx = sh->qd_idx;
1662 d0_idx = raid6_d0(sh);
1664 pr_debug("compute_parity, stripe %llu, method %d\n",
1665 (unsigned long long)sh->sector, method);
1668 case READ_MODIFY_WRITE:
1669 BUG(); /* READ_MODIFY_WRITE N/A for RAID-6 */
1670 case RECONSTRUCT_WRITE:
1671 for (i= disks; i-- ;)
1672 if ( i != pd_idx && i != qd_idx && sh->dev[i].towrite ) {
1673 chosen = sh->dev[i].towrite;
1674 sh->dev[i].towrite = NULL;
1676 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1677 wake_up(&conf->wait_for_overlap);
1679 BUG_ON(sh->dev[i].written);
1680 sh->dev[i].written = chosen;
1684 BUG(); /* Not implemented yet */
1687 for (i = disks; i--;)
1688 if (sh->dev[i].written) {
1689 sector_t sector = sh->dev[i].sector;
1690 struct bio *wbi = sh->dev[i].written;
1691 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
1692 copy_data(1, wbi, sh->dev[i].page, sector);
1693 wbi = r5_next_bio(wbi, sector);
1696 set_bit(R5_LOCKED, &sh->dev[i].flags);
1697 set_bit(R5_UPTODATE, &sh->dev[i].flags);
1700 /* Note that unlike RAID-5, the ordering of the disks matters greatly.*/
1702 for (i = 0; i < disks; i++)
1703 ptrs[i] = (void *)raid6_empty_zero_page;
1708 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1710 ptrs[slot] = page_address(sh->dev[i].page);
1711 if (slot < syndrome_disks &&
1712 !test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
1713 printk(KERN_ERR "block %d/%d not uptodate "
1714 "on parity calc\n", i, count);
1718 i = raid6_next_disk(i, disks);
1719 } while (i != d0_idx);
1720 BUG_ON(count != syndrome_disks);
1722 raid6_call.gen_syndrome(syndrome_disks+2, STRIPE_SIZE, ptrs);
1725 case RECONSTRUCT_WRITE:
1726 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
1727 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
1728 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
1729 set_bit(R5_LOCKED, &sh->dev[qd_idx].flags);
1732 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
1733 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
1739 /* Compute one missing block */
1740 static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero)
1742 int i, count, disks = sh->disks;
1743 void *ptr[MAX_XOR_BLOCKS], *dest, *p;
1744 int qd_idx = sh->qd_idx;
1746 pr_debug("compute_block_1, stripe %llu, idx %d\n",
1747 (unsigned long long)sh->sector, dd_idx);
1749 if ( dd_idx == qd_idx ) {
1750 /* We're actually computing the Q drive */
1751 compute_parity6(sh, UPDATE_PARITY);
1753 dest = page_address(sh->dev[dd_idx].page);
1754 if (!nozero) memset(dest, 0, STRIPE_SIZE);
1756 for (i = disks ; i--; ) {
1757 if (i == dd_idx || i == qd_idx)
1759 p = page_address(sh->dev[i].page);
1760 if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
1763 printk("compute_block() %d, stripe %llu, %d"
1764 " not present\n", dd_idx,
1765 (unsigned long long)sh->sector, i);
1770 xor_blocks(count, STRIPE_SIZE, dest, ptr);
1771 if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
1772 else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
1776 /* Compute two missing blocks */
1777 static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
1779 int i, count, disks = sh->disks;
1780 int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1781 int d0_idx = raid6_d0(sh);
1782 int faila = -1, failb = -1;
1783 /**** FIX THIS: This could be very bad if disks is close to 256 ****/
1784 void *ptrs[syndrome_disks+2];
1786 for (i = 0; i < disks ; i++)
1787 ptrs[i] = (void *)raid6_empty_zero_page;
1791 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1793 ptrs[slot] = page_address(sh->dev[i].page);
1799 i = raid6_next_disk(i, disks);
1800 } while (i != d0_idx);
1801 BUG_ON(count != syndrome_disks);
1803 BUG_ON(faila == failb);
1804 if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
1806 pr_debug("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
1807 (unsigned long long)sh->sector, dd_idx1, dd_idx2,
1810 if (failb == syndrome_disks+1) {
1811 /* Q disk is one of the missing disks */
1812 if (faila == syndrome_disks) {
1813 /* Missing P+Q, just recompute */
1814 compute_parity6(sh, UPDATE_PARITY);
1817 /* We're missing D+Q; recompute D from P */
1818 compute_block_1(sh, ((dd_idx1 == sh->qd_idx) ?
1821 compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */
1826 /* We're missing D+P or D+D; */
1827 if (failb == syndrome_disks) {
1828 /* We're missing D+P. */
1829 raid6_datap_recov(syndrome_disks+2, STRIPE_SIZE, faila, ptrs);
1831 /* We're missing D+D. */
1832 raid6_2data_recov(syndrome_disks+2, STRIPE_SIZE, faila, failb,
1836 /* Both the above update both missing blocks */
1837 set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags);
1838 set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags);
1842 schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s,
1843 int rcw, int expand)
1845 int i, pd_idx = sh->pd_idx, disks = sh->disks;
1848 /* if we are not expanding this is a proper write request, and
1849 * there will be bios with new data to be drained into the
1853 sh->reconstruct_state = reconstruct_state_drain_run;
1854 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
1856 sh->reconstruct_state = reconstruct_state_run;
1858 set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
1860 for (i = disks; i--; ) {
1861 struct r5dev *dev = &sh->dev[i];
1864 set_bit(R5_LOCKED, &dev->flags);
1865 set_bit(R5_Wantdrain, &dev->flags);
1867 clear_bit(R5_UPTODATE, &dev->flags);
1871 if (s->locked + 1 == disks)
1872 if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
1873 atomic_inc(&sh->raid_conf->pending_full_writes);
1875 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
1876 test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
1878 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
1879 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
1880 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
1881 set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
1883 for (i = disks; i--; ) {
1884 struct r5dev *dev = &sh->dev[i];
1889 (test_bit(R5_UPTODATE, &dev->flags) ||
1890 test_bit(R5_Wantcompute, &dev->flags))) {
1891 set_bit(R5_Wantdrain, &dev->flags);
1892 set_bit(R5_LOCKED, &dev->flags);
1893 clear_bit(R5_UPTODATE, &dev->flags);
1899 /* keep the parity disk locked while asynchronous operations
1902 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
1903 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
1906 pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
1907 __func__, (unsigned long long)sh->sector,
1908 s->locked, s->ops_request);
1912 * Each stripe/dev can have one or more bion attached.
1913 * toread/towrite point to the first in a chain.
1914 * The bi_next chain must be in order.
1916 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
1919 raid5_conf_t *conf = sh->raid_conf;
1922 pr_debug("adding bh b#%llu to stripe s#%llu\n",
1923 (unsigned long long)bi->bi_sector,
1924 (unsigned long long)sh->sector);
1927 spin_lock(&sh->lock);
1928 spin_lock_irq(&conf->device_lock);
1930 bip = &sh->dev[dd_idx].towrite;
1931 if (*bip == NULL && sh->dev[dd_idx].written == NULL)
1934 bip = &sh->dev[dd_idx].toread;
1935 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
1936 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
1938 bip = & (*bip)->bi_next;
1940 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
1943 BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
1947 bi->bi_phys_segments++;
1948 spin_unlock_irq(&conf->device_lock);
1949 spin_unlock(&sh->lock);
1951 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
1952 (unsigned long long)bi->bi_sector,
1953 (unsigned long long)sh->sector, dd_idx);
1955 if (conf->mddev->bitmap && firstwrite) {
1956 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
1958 sh->bm_seq = conf->seq_flush+1;
1959 set_bit(STRIPE_BIT_DELAY, &sh->state);
1963 /* check if page is covered */
1964 sector_t sector = sh->dev[dd_idx].sector;
1965 for (bi=sh->dev[dd_idx].towrite;
1966 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
1967 bi && bi->bi_sector <= sector;
1968 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
1969 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
1970 sector = bi->bi_sector + (bi->bi_size>>9);
1972 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
1973 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
1978 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
1979 spin_unlock_irq(&conf->device_lock);
1980 spin_unlock(&sh->lock);
1984 static void end_reshape(raid5_conf_t *conf);
1986 static int page_is_zero(struct page *p)
1988 char *a = page_address(p);
1989 return ((*(u32*)a) == 0 &&
1990 memcmp(a, a+4, STRIPE_SIZE-4)==0);
1993 static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
1994 struct stripe_head *sh)
1996 int sectors_per_chunk =
1997 previous ? (conf->prev_chunk >> 9)
1998 : (conf->chunk_size >> 9);
2000 int chunk_offset = sector_div(stripe, sectors_per_chunk);
2001 int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2003 raid5_compute_sector(conf,
2004 stripe * (disks - conf->max_degraded)
2005 *sectors_per_chunk + chunk_offset,
2011 handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh,
2012 struct stripe_head_state *s, int disks,
2013 struct bio **return_bi)
2016 for (i = disks; i--; ) {
2020 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2023 rdev = rcu_dereference(conf->disks[i].rdev);
2024 if (rdev && test_bit(In_sync, &rdev->flags))
2025 /* multiple read failures in one stripe */
2026 md_error(conf->mddev, rdev);
2029 spin_lock_irq(&conf->device_lock);
2030 /* fail all writes first */
2031 bi = sh->dev[i].towrite;
2032 sh->dev[i].towrite = NULL;
2038 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
2039 wake_up(&conf->wait_for_overlap);
2041 while (bi && bi->bi_sector <
2042 sh->dev[i].sector + STRIPE_SECTORS) {
2043 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
2044 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2045 if (!raid5_dec_bi_phys_segments(bi)) {
2046 md_write_end(conf->mddev);
2047 bi->bi_next = *return_bi;
2052 /* and fail all 'written' */
2053 bi = sh->dev[i].written;
2054 sh->dev[i].written = NULL;
2055 if (bi) bitmap_end = 1;
2056 while (bi && bi->bi_sector <
2057 sh->dev[i].sector + STRIPE_SECTORS) {
2058 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
2059 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2060 if (!raid5_dec_bi_phys_segments(bi)) {
2061 md_write_end(conf->mddev);
2062 bi->bi_next = *return_bi;
2068 /* fail any reads if this device is non-operational and
2069 * the data has not reached the cache yet.
2071 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
2072 (!test_bit(R5_Insync, &sh->dev[i].flags) ||
2073 test_bit(R5_ReadError, &sh->dev[i].flags))) {
2074 bi = sh->dev[i].toread;
2075 sh->dev[i].toread = NULL;
2076 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
2077 wake_up(&conf->wait_for_overlap);
2078 if (bi) s->to_read--;
2079 while (bi && bi->bi_sector <
2080 sh->dev[i].sector + STRIPE_SECTORS) {
2081 struct bio *nextbi =
2082 r5_next_bio(bi, sh->dev[i].sector);
2083 clear_bit(BIO_UPTODATE, &bi->bi_flags);
2084 if (!raid5_dec_bi_phys_segments(bi)) {
2085 bi->bi_next = *return_bi;
2091 spin_unlock_irq(&conf->device_lock);
2093 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
2094 STRIPE_SECTORS, 0, 0);
2097 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
2098 if (atomic_dec_and_test(&conf->pending_full_writes))
2099 md_wakeup_thread(conf->mddev->thread);
2102 /* fetch_block5 - checks the given member device to see if its data needs
2103 * to be read or computed to satisfy a request.
2105 * Returns 1 when no more member devices need to be checked, otherwise returns
2106 * 0 to tell the loop in handle_stripe_fill5 to continue
2108 static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s,
2109 int disk_idx, int disks)
2111 struct r5dev *dev = &sh->dev[disk_idx];
2112 struct r5dev *failed_dev = &sh->dev[s->failed_num];
2114 /* is the data in this block needed, and can we get it? */
2115 if (!test_bit(R5_LOCKED, &dev->flags) &&
2116 !test_bit(R5_UPTODATE, &dev->flags) &&
2118 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
2119 s->syncing || s->expanding ||
2121 (failed_dev->toread ||
2122 (failed_dev->towrite &&
2123 !test_bit(R5_OVERWRITE, &failed_dev->flags)))))) {
2124 /* We would like to get this block, possibly by computing it,
2125 * otherwise read it if the backing disk is insync
2127 if ((s->uptodate == disks - 1) &&
2128 (s->failed && disk_idx == s->failed_num)) {
2129 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2130 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
2131 set_bit(R5_Wantcompute, &dev->flags);
2132 sh->ops.target = disk_idx;
2134 /* Careful: from this point on 'uptodate' is in the eye
2135 * of raid5_run_ops which services 'compute' operations
2136 * before writes. R5_Wantcompute flags a block that will
2137 * be R5_UPTODATE by the time it is needed for a
2138 * subsequent operation.
2141 return 1; /* uptodate + compute == disks */
2142 } else if (test_bit(R5_Insync, &dev->flags)) {
2143 set_bit(R5_LOCKED, &dev->flags);
2144 set_bit(R5_Wantread, &dev->flags);
2146 pr_debug("Reading block %d (sync=%d)\n", disk_idx,
2155 * handle_stripe_fill5 - read or compute data to satisfy pending requests.
2157 static void handle_stripe_fill5(struct stripe_head *sh,
2158 struct stripe_head_state *s, int disks)
2162 /* look for blocks to read/compute, skip this if a compute
2163 * is already in flight, or if the stripe contents are in the
2164 * midst of changing due to a write
2166 if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
2167 !sh->reconstruct_state)
2168 for (i = disks; i--; )
2169 if (fetch_block5(sh, s, i, disks))
2171 set_bit(STRIPE_HANDLE, &sh->state);
2174 static void handle_stripe_fill6(struct stripe_head *sh,
2175 struct stripe_head_state *s, struct r6_state *r6s,
2179 for (i = disks; i--; ) {
2180 struct r5dev *dev = &sh->dev[i];
2181 if (!test_bit(R5_LOCKED, &dev->flags) &&
2182 !test_bit(R5_UPTODATE, &dev->flags) &&
2183 (dev->toread || (dev->towrite &&
2184 !test_bit(R5_OVERWRITE, &dev->flags)) ||
2185 s->syncing || s->expanding ||
2187 (sh->dev[r6s->failed_num[0]].toread ||
2190 (sh->dev[r6s->failed_num[1]].toread ||
2192 /* we would like to get this block, possibly
2193 * by computing it, but we might not be able to
2195 if ((s->uptodate == disks - 1) &&
2196 (s->failed && (i == r6s->failed_num[0] ||
2197 i == r6s->failed_num[1]))) {
2198 pr_debug("Computing stripe %llu block %d\n",
2199 (unsigned long long)sh->sector, i);
2200 compute_block_1(sh, i, 0);
2202 } else if ( s->uptodate == disks-2 && s->failed >= 2 ) {
2203 /* Computing 2-failure is *very* expensive; only
2204 * do it if failed >= 2
2207 for (other = disks; other--; ) {
2210 if (!test_bit(R5_UPTODATE,
2211 &sh->dev[other].flags))
2215 pr_debug("Computing stripe %llu blocks %d,%d\n",
2216 (unsigned long long)sh->sector,
2218 compute_block_2(sh, i, other);
2220 } else if (test_bit(R5_Insync, &dev->flags)) {
2221 set_bit(R5_LOCKED, &dev->flags);
2222 set_bit(R5_Wantread, &dev->flags);
2224 pr_debug("Reading block %d (sync=%d)\n",
2229 set_bit(STRIPE_HANDLE, &sh->state);
2233 /* handle_stripe_clean_event
2234 * any written block on an uptodate or failed drive can be returned.
2235 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
2236 * never LOCKED, so we don't need to test 'failed' directly.
2238 static void handle_stripe_clean_event(raid5_conf_t *conf,
2239 struct stripe_head *sh, int disks, struct bio **return_bi)
2244 for (i = disks; i--; )
2245 if (sh->dev[i].written) {
2247 if (!test_bit(R5_LOCKED, &dev->flags) &&
2248 test_bit(R5_UPTODATE, &dev->flags)) {
2249 /* We can return any write requests */
2250 struct bio *wbi, *wbi2;
2252 pr_debug("Return write for disc %d\n", i);
2253 spin_lock_irq(&conf->device_lock);
2255 dev->written = NULL;
2256 while (wbi && wbi->bi_sector <
2257 dev->sector + STRIPE_SECTORS) {
2258 wbi2 = r5_next_bio(wbi, dev->sector);
2259 if (!raid5_dec_bi_phys_segments(wbi)) {
2260 md_write_end(conf->mddev);
2261 wbi->bi_next = *return_bi;
2266 if (dev->towrite == NULL)
2268 spin_unlock_irq(&conf->device_lock);
2270 bitmap_endwrite(conf->mddev->bitmap,
2273 !test_bit(STRIPE_DEGRADED, &sh->state),
2278 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
2279 if (atomic_dec_and_test(&conf->pending_full_writes))
2280 md_wakeup_thread(conf->mddev->thread);
2283 static void handle_stripe_dirtying5(raid5_conf_t *conf,
2284 struct stripe_head *sh, struct stripe_head_state *s, int disks)
2286 int rmw = 0, rcw = 0, i;
2287 for (i = disks; i--; ) {
2288 /* would I have to read this buffer for read_modify_write */
2289 struct r5dev *dev = &sh->dev[i];
2290 if ((dev->towrite || i == sh->pd_idx) &&
2291 !test_bit(R5_LOCKED, &dev->flags) &&
2292 !(test_bit(R5_UPTODATE, &dev->flags) ||
2293 test_bit(R5_Wantcompute, &dev->flags))) {
2294 if (test_bit(R5_Insync, &dev->flags))
2297 rmw += 2*disks; /* cannot read it */
2299 /* Would I have to read this buffer for reconstruct_write */
2300 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
2301 !test_bit(R5_LOCKED, &dev->flags) &&
2302 !(test_bit(R5_UPTODATE, &dev->flags) ||
2303 test_bit(R5_Wantcompute, &dev->flags))) {
2304 if (test_bit(R5_Insync, &dev->flags)) rcw++;
2309 pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2310 (unsigned long long)sh->sector, rmw, rcw);
2311 set_bit(STRIPE_HANDLE, &sh->state);
2312 if (rmw < rcw && rmw > 0)
2313 /* prefer read-modify-write, but need to get some data */
2314 for (i = disks; i--; ) {
2315 struct r5dev *dev = &sh->dev[i];
2316 if ((dev->towrite || i == sh->pd_idx) &&
2317 !test_bit(R5_LOCKED, &dev->flags) &&
2318 !(test_bit(R5_UPTODATE, &dev->flags) ||
2319 test_bit(R5_Wantcompute, &dev->flags)) &&
2320 test_bit(R5_Insync, &dev->flags)) {
2322 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2323 pr_debug("Read_old block "
2324 "%d for r-m-w\n", i);
2325 set_bit(R5_LOCKED, &dev->flags);
2326 set_bit(R5_Wantread, &dev->flags);
2329 set_bit(STRIPE_DELAYED, &sh->state);
2330 set_bit(STRIPE_HANDLE, &sh->state);
2334 if (rcw <= rmw && rcw > 0)
2335 /* want reconstruct write, but need to get some data */
2336 for (i = disks; i--; ) {
2337 struct r5dev *dev = &sh->dev[i];
2338 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2340 !test_bit(R5_LOCKED, &dev->flags) &&
2341 !(test_bit(R5_UPTODATE, &dev->flags) ||
2342 test_bit(R5_Wantcompute, &dev->flags)) &&
2343 test_bit(R5_Insync, &dev->flags)) {
2345 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2346 pr_debug("Read_old block "
2347 "%d for Reconstruct\n", i);
2348 set_bit(R5_LOCKED, &dev->flags);
2349 set_bit(R5_Wantread, &dev->flags);
2352 set_bit(STRIPE_DELAYED, &sh->state);
2353 set_bit(STRIPE_HANDLE, &sh->state);
2357 /* now if nothing is locked, and if we have enough data,
2358 * we can start a write request
2360 /* since handle_stripe can be called at any time we need to handle the
2361 * case where a compute block operation has been submitted and then a
2362 * subsequent call wants to start a write request. raid5_run_ops only
2363 * handles the case where compute block and postxor are requested
2364 * simultaneously. If this is not the case then new writes need to be
2365 * held off until the compute completes.
2367 if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
2368 (s->locked == 0 && (rcw == 0 || rmw == 0) &&
2369 !test_bit(STRIPE_BIT_DELAY, &sh->state)))
2370 schedule_reconstruction5(sh, s, rcw == 0, 0);
2373 static void handle_stripe_dirtying6(raid5_conf_t *conf,
2374 struct stripe_head *sh, struct stripe_head_state *s,
2375 struct r6_state *r6s, int disks)
2377 int rcw = 0, must_compute = 0, pd_idx = sh->pd_idx, i;
2378 int qd_idx = sh->qd_idx;
2379 for (i = disks; i--; ) {
2380 struct r5dev *dev = &sh->dev[i];
2381 /* Would I have to read this buffer for reconstruct_write */
2382 if (!test_bit(R5_OVERWRITE, &dev->flags)
2383 && i != pd_idx && i != qd_idx
2384 && (!test_bit(R5_LOCKED, &dev->flags)
2386 !test_bit(R5_UPTODATE, &dev->flags)) {
2387 if (test_bit(R5_Insync, &dev->flags)) rcw++;
2389 pr_debug("raid6: must_compute: "
2390 "disk %d flags=%#lx\n", i, dev->flags);
2395 pr_debug("for sector %llu, rcw=%d, must_compute=%d\n",
2396 (unsigned long long)sh->sector, rcw, must_compute);
2397 set_bit(STRIPE_HANDLE, &sh->state);
2400 /* want reconstruct write, but need to get some data */
2401 for (i = disks; i--; ) {
2402 struct r5dev *dev = &sh->dev[i];
2403 if (!test_bit(R5_OVERWRITE, &dev->flags)
2404 && !(s->failed == 0 && (i == pd_idx || i == qd_idx))
2405 && !test_bit(R5_LOCKED, &dev->flags) &&
2406 !test_bit(R5_UPTODATE, &dev->flags) &&
2407 test_bit(R5_Insync, &dev->flags)) {
2409 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2410 pr_debug("Read_old stripe %llu "
2411 "block %d for Reconstruct\n",
2412 (unsigned long long)sh->sector, i);
2413 set_bit(R5_LOCKED, &dev->flags);
2414 set_bit(R5_Wantread, &dev->flags);
2417 pr_debug("Request delayed stripe %llu "
2418 "block %d for Reconstruct\n",
2419 (unsigned long long)sh->sector, i);
2420 set_bit(STRIPE_DELAYED, &sh->state);
2421 set_bit(STRIPE_HANDLE, &sh->state);
2425 /* now if nothing is locked, and if we have enough data, we can start a
2428 if (s->locked == 0 && rcw == 0 &&
2429 !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
2430 if (must_compute > 0) {
2431 /* We have failed blocks and need to compute them */
2432 switch (s->failed) {
2436 compute_block_1(sh, r6s->failed_num[0], 0);
2439 compute_block_2(sh, r6s->failed_num[0],
2440 r6s->failed_num[1]);
2442 default: /* This request should have been failed? */
2447 pr_debug("Computing parity for stripe %llu\n",
2448 (unsigned long long)sh->sector);
2449 compute_parity6(sh, RECONSTRUCT_WRITE);
2450 /* now every locked buffer is ready to be written */
2451 for (i = disks; i--; )
2452 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
2453 pr_debug("Writing stripe %llu block %d\n",
2454 (unsigned long long)sh->sector, i);
2456 set_bit(R5_Wantwrite, &sh->dev[i].flags);
2458 if (s->locked == disks)
2459 if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2460 atomic_inc(&conf->pending_full_writes);
2461 /* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */
2462 set_bit(STRIPE_INSYNC, &sh->state);
2464 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2465 atomic_dec(&conf->preread_active_stripes);
2466 if (atomic_read(&conf->preread_active_stripes) <
2468 md_wakeup_thread(conf->mddev->thread);
2473 static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
2474 struct stripe_head_state *s, int disks)
2476 struct r5dev *dev = NULL;
2478 set_bit(STRIPE_HANDLE, &sh->state);
2480 switch (sh->check_state) {
2481 case check_state_idle:
2482 /* start a new check operation if there are no failures */
2483 if (s->failed == 0) {
2484 BUG_ON(s->uptodate != disks);
2485 sh->check_state = check_state_run;
2486 set_bit(STRIPE_OP_CHECK, &s->ops_request);
2487 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
2491 dev = &sh->dev[s->failed_num];
2493 case check_state_compute_result:
2494 sh->check_state = check_state_idle;
2496 dev = &sh->dev[sh->pd_idx];
2498 /* check that a write has not made the stripe insync */
2499 if (test_bit(STRIPE_INSYNC, &sh->state))
2502 /* either failed parity check, or recovery is happening */
2503 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
2504 BUG_ON(s->uptodate != disks);
2506 set_bit(R5_LOCKED, &dev->flags);
2508 set_bit(R5_Wantwrite, &dev->flags);
2510 clear_bit(STRIPE_DEGRADED, &sh->state);
2511 set_bit(STRIPE_INSYNC, &sh->state);
2513 case check_state_run:
2514 break; /* we will be called again upon completion */
2515 case check_state_check_result:
2516 sh->check_state = check_state_idle;
2518 /* if a failure occurred during the check operation, leave
2519 * STRIPE_INSYNC not set and let the stripe be handled again
2524 /* handle a successful check operation, if parity is correct
2525 * we are done. Otherwise update the mismatch count and repair
2526 * parity if !MD_RECOVERY_CHECK
2528 if (sh->ops.zero_sum_result == 0)
2529 /* parity is correct (on disc,
2530 * not in buffer any more)
2532 set_bit(STRIPE_INSYNC, &sh->state);
2534 conf->mddev->resync_mismatches += STRIPE_SECTORS;
2535 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
2536 /* don't try to repair!! */
2537 set_bit(STRIPE_INSYNC, &sh->state);
2539 sh->check_state = check_state_compute_run;
2540 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2541 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
2542 set_bit(R5_Wantcompute,
2543 &sh->dev[sh->pd_idx].flags);
2544 sh->ops.target = sh->pd_idx;
2549 case check_state_compute_run:
2552 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
2553 __func__, sh->check_state,
2554 (unsigned long long) sh->sector);
2560 static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh,
2561 struct stripe_head_state *s,
2562 struct r6_state *r6s, struct page *tmp_page,
2565 int update_p = 0, update_q = 0;
2567 int pd_idx = sh->pd_idx;
2568 int qd_idx = sh->qd_idx;
2570 set_bit(STRIPE_HANDLE, &sh->state);
2572 BUG_ON(s->failed > 2);
2573 BUG_ON(s->uptodate < disks);
2574 /* Want to check and possibly repair P and Q.
2575 * However there could be one 'failed' device, in which
2576 * case we can only check one of them, possibly using the
2577 * other to generate missing data
2580 /* If !tmp_page, we cannot do the calculations,
2581 * but as we have set STRIPE_HANDLE, we will soon be called
2582 * by stripe_handle with a tmp_page - just wait until then.
2585 if (s->failed == r6s->q_failed) {
2586 /* The only possible failed device holds 'Q', so it
2587 * makes sense to check P (If anything else were failed,
2588 * we would have used P to recreate it).
2590 compute_block_1(sh, pd_idx, 1);
2591 if (!page_is_zero(sh->dev[pd_idx].page)) {
2592 compute_block_1(sh, pd_idx, 0);
2596 if (!r6s->q_failed && s->failed < 2) {
2597 /* q is not failed, and we didn't use it to generate
2598 * anything, so it makes sense to check it
2600 memcpy(page_address(tmp_page),
2601 page_address(sh->dev[qd_idx].page),
2603 compute_parity6(sh, UPDATE_PARITY);
2604 if (memcmp(page_address(tmp_page),
2605 page_address(sh->dev[qd_idx].page),
2606 STRIPE_SIZE) != 0) {
2607 clear_bit(STRIPE_INSYNC, &sh->state);
2611 if (update_p || update_q) {
2612 conf->mddev->resync_mismatches += STRIPE_SECTORS;
2613 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
2614 /* don't try to repair!! */
2615 update_p = update_q = 0;
2618 /* now write out any block on a failed drive,
2619 * or P or Q if they need it
2622 if (s->failed == 2) {
2623 dev = &sh->dev[r6s->failed_num[1]];
2625 set_bit(R5_LOCKED, &dev->flags);
2626 set_bit(R5_Wantwrite, &dev->flags);
2628 if (s->failed >= 1) {
2629 dev = &sh->dev[r6s->failed_num[0]];
2631 set_bit(R5_LOCKED, &dev->flags);
2632 set_bit(R5_Wantwrite, &dev->flags);
2636 dev = &sh->dev[pd_idx];
2638 set_bit(R5_LOCKED, &dev->flags);
2639 set_bit(R5_Wantwrite, &dev->flags);
2642 dev = &sh->dev[qd_idx];
2644 set_bit(R5_LOCKED, &dev->flags);
2645 set_bit(R5_Wantwrite, &dev->flags);
2647 clear_bit(STRIPE_DEGRADED, &sh->state);
2649 set_bit(STRIPE_INSYNC, &sh->state);
2653 static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
2654 struct r6_state *r6s)
2658 /* We have read all the blocks in this stripe and now we need to
2659 * copy some of them into a target stripe for expand.
2661 struct dma_async_tx_descriptor *tx = NULL;
2662 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
2663 for (i = 0; i < sh->disks; i++)
2664 if (i != sh->pd_idx && i != sh->qd_idx) {
2666 struct stripe_head *sh2;
2668 sector_t bn = compute_blocknr(sh, i, 1);
2669 sector_t s = raid5_compute_sector(conf, bn, 0,
2671 sh2 = get_active_stripe(conf, s, 0, 1);
2673 /* so far only the early blocks of this stripe
2674 * have been requested. When later blocks
2675 * get requested, we will try again
2678 if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
2679 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
2680 /* must have already done this block */
2681 release_stripe(sh2);
2685 /* place all the copies on one channel */
2686 tx = async_memcpy(sh2->dev[dd_idx].page,
2687 sh->dev[i].page, 0, 0, STRIPE_SIZE,
2690 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
2691 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
2692 for (j = 0; j < conf->raid_disks; j++)
2693 if (j != sh2->pd_idx &&
2694 (!r6s || j != sh2->qd_idx) &&
2695 !test_bit(R5_Expanded, &sh2->dev[j].flags))
2697 if (j == conf->raid_disks) {
2698 set_bit(STRIPE_EXPAND_READY, &sh2->state);
2699 set_bit(STRIPE_HANDLE, &sh2->state);
2701 release_stripe(sh2);
2704 /* done submitting copies, wait for them to complete */
2707 dma_wait_for_async_tx(tx);
2713 * handle_stripe - do things to a stripe.
2715 * We lock the stripe and then examine the state of various bits
2716 * to see what needs to be done.
2718 * return some read request which now have data
2719 * return some write requests which are safely on disc
2720 * schedule a read on some buffers
2721 * schedule a write of some buffers
2722 * return confirmation of parity correctness
2724 * buffers are taken off read_list or write_list, and bh_cache buffers
2725 * get BH_Lock set before the stripe lock is released.
2729 static bool handle_stripe5(struct stripe_head *sh)
2731 raid5_conf_t *conf = sh->raid_conf;
2732 int disks = sh->disks, i;
2733 struct bio *return_bi = NULL;
2734 struct stripe_head_state s;
2736 mdk_rdev_t *blocked_rdev = NULL;
2739 memset(&s, 0, sizeof(s));
2740 pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d "
2741 "reconstruct:%d\n", (unsigned long long)sh->sector, sh->state,
2742 atomic_read(&sh->count), sh->pd_idx, sh->check_state,
2743 sh->reconstruct_state);
2745 spin_lock(&sh->lock);
2746 clear_bit(STRIPE_HANDLE, &sh->state);
2747 clear_bit(STRIPE_DELAYED, &sh->state);
2749 s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
2750 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
2751 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
2753 /* Now to look around and see what can be done */
2755 for (i=disks; i--; ) {
2757 struct r5dev *dev = &sh->dev[i];
2758 clear_bit(R5_Insync, &dev->flags);
2760 pr_debug("check %d: state 0x%lx toread %p read %p write %p "
2761 "written %p\n", i, dev->flags, dev->toread, dev->read,
2762 dev->towrite, dev->written);
2764 /* maybe we can request a biofill operation
2766 * new wantfill requests are only permitted while
2767 * ops_complete_biofill is guaranteed to be inactive
2769 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
2770 !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
2771 set_bit(R5_Wantfill, &dev->flags);
2773 /* now count some things */
2774 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
2775 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;
2776 if (test_bit(R5_Wantcompute, &dev->flags)) s.compute++;
2778 if (test_bit(R5_Wantfill, &dev->flags))
2780 else if (dev->toread)
2784 if (!test_bit(R5_OVERWRITE, &dev->flags))
2789 rdev = rcu_dereference(conf->disks[i].rdev);
2790 if (blocked_rdev == NULL &&
2791 rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
2792 blocked_rdev = rdev;
2793 atomic_inc(&rdev->nr_pending);
2795 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
2796 /* The ReadError flag will just be confusing now */
2797 clear_bit(R5_ReadError, &dev->flags);
2798 clear_bit(R5_ReWrite, &dev->flags);
2800 if (!rdev || !test_bit(In_sync, &rdev->flags)
2801 || test_bit(R5_ReadError, &dev->flags)) {
2805 set_bit(R5_Insync, &dev->flags);
2809 if (unlikely(blocked_rdev)) {
2810 if (s.syncing || s.expanding || s.expanded ||
2811 s.to_write || s.written) {
2812 set_bit(STRIPE_HANDLE, &sh->state);
2815 /* There is nothing for the blocked_rdev to block */
2816 rdev_dec_pending(blocked_rdev, conf->mddev);
2817 blocked_rdev = NULL;
2820 if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
2821 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
2822 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
2825 pr_debug("locked=%d uptodate=%d to_read=%d"
2826 " to_write=%d failed=%d failed_num=%d\n",
2827 s.locked, s.uptodate, s.to_read, s.to_write,
2828 s.failed, s.failed_num);
2829 /* check if the array has lost two devices and, if so, some requests might
2832 if (s.failed > 1 && s.to_read+s.to_write+s.written)
2833 handle_failed_stripe(conf, sh, &s, disks, &return_bi);
2834 if (s.failed > 1 && s.syncing) {
2835 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
2836 clear_bit(STRIPE_SYNCING, &sh->state);
2840 /* might be able to return some write requests if the parity block
2841 * is safe, or on a failed drive
2843 dev = &sh->dev[sh->pd_idx];
2845 ((test_bit(R5_Insync, &dev->flags) &&
2846 !test_bit(R5_LOCKED, &dev->flags) &&
2847 test_bit(R5_UPTODATE, &dev->flags)) ||
2848 (s.failed == 1 && s.failed_num == sh->pd_idx)))
2849 handle_stripe_clean_event(conf, sh, disks, &return_bi);
2851 /* Now we might consider reading some blocks, either to check/generate
2852 * parity, or to satisfy requests
2853 * or to load a block that is being partially written.
2855 if (s.to_read || s.non_overwrite ||
2856 (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
2857 handle_stripe_fill5(sh, &s, disks);
2859 /* Now we check to see if any write operations have recently
2863 if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
2865 if (sh->reconstruct_state == reconstruct_state_drain_result ||
2866 sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
2867 sh->reconstruct_state = reconstruct_state_idle;
2869 /* All the 'written' buffers and the parity block are ready to
2870 * be written back to disk
2872 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags));
2873 for (i = disks; i--; ) {
2875 if (test_bit(R5_LOCKED, &dev->flags) &&
2876 (i == sh->pd_idx || dev->written)) {
2877 pr_debug("Writing block %d\n", i);
2878 set_bit(R5_Wantwrite, &dev->flags);
2881 if (!test_bit(R5_Insync, &dev->flags) ||
2882 (i == sh->pd_idx && s.failed == 0))
2883 set_bit(STRIPE_INSYNC, &sh->state);
2886 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2887 atomic_dec(&conf->preread_active_stripes);
2888 if (atomic_read(&conf->preread_active_stripes) <
2890 md_wakeup_thread(conf->mddev->thread);
2894 /* Now to consider new write requests and what else, if anything
2895 * should be read. We do not handle new writes when:
2896 * 1/ A 'write' operation (copy+xor) is already in flight.
2897 * 2/ A 'check' operation is in flight, as it may clobber the parity
2900 if (s.to_write && !sh->reconstruct_state && !sh->check_state)
2901 handle_stripe_dirtying5(conf, sh, &s, disks);
2903 /* maybe we need to check and possibly fix the parity for this stripe
2904 * Any reads will already have been scheduled, so we just see if enough
2905 * data is available. The parity check is held off while parity
2906 * dependent operations are in flight.
2908 if (sh->check_state ||
2909 (s.syncing && s.locked == 0 &&
2910 !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
2911 !test_bit(STRIPE_INSYNC, &sh->state)))
2912 handle_parity_checks5(conf, sh, &s, disks);
2914 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
2915 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
2916 clear_bit(STRIPE_SYNCING, &sh->state);
2919 /* If the failed drive is just a ReadError, then we might need to progress
2920 * the repair/check process
2922 if (s.failed == 1 && !conf->mddev->ro &&
2923 test_bit(R5_ReadError, &sh->dev[s.failed_num].flags)
2924 && !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags)
2925 && test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags)
2927 dev = &sh->dev[s.failed_num];
2928 if (!test_bit(R5_ReWrite, &dev->flags)) {
2929 set_bit(R5_Wantwrite, &dev->flags);
2930 set_bit(R5_ReWrite, &dev->flags);
2931 set_bit(R5_LOCKED, &dev->flags);
2934 /* let's read it back */
2935 set_bit(R5_Wantread, &dev->flags);
2936 set_bit(R5_LOCKED, &dev->flags);
2941 /* Finish reconstruct operations initiated by the expansion process */
2942 if (sh->reconstruct_state == reconstruct_state_result) {
2943 struct stripe_head *sh2
2944 = get_active_stripe(conf, sh->sector, 1, 1);
2945 if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) {
2946 /* sh cannot be written until sh2 has been read.
2947 * so arrange for sh to be delayed a little
2949 set_bit(STRIPE_DELAYED, &sh->state);
2950 set_bit(STRIPE_HANDLE, &sh->state);
2951 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
2953 atomic_inc(&conf->preread_active_stripes);
2954 release_stripe(sh2);
2958 release_stripe(sh2);
2960 sh->reconstruct_state = reconstruct_state_idle;
2961 clear_bit(STRIPE_EXPANDING, &sh->state);
2962 for (i = conf->raid_disks; i--; ) {
2963 set_bit(R5_Wantwrite, &sh->dev[i].flags);
2964 set_bit(R5_LOCKED, &sh->dev[i].flags);
2969 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
2970 !sh->reconstruct_state) {
2971 /* Need to write out all blocks after computing parity */
2972 sh->disks = conf->raid_disks;
2973 stripe_set_idx(sh->sector, conf, 0, sh);
2974 schedule_reconstruction5(sh, &s, 1, 1);
2975 } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
2976 clear_bit(STRIPE_EXPAND_READY, &sh->state);
2977 atomic_dec(&conf->reshape_stripes);
2978 wake_up(&conf->wait_for_overlap);
2979 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
2982 if (s.expanding && s.locked == 0 &&
2983 !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
2984 handle_stripe_expansion(conf, sh, NULL);
2987 spin_unlock(&sh->lock);
2989 /* wait for this device to become unblocked */
2990 if (unlikely(blocked_rdev))
2991 md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
2994 raid5_run_ops(sh, s.ops_request);
2998 return_io(return_bi);
3000 return blocked_rdev == NULL;
3003 static bool handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
3005 raid5_conf_t *conf = sh->raid_conf;
3006 int disks = sh->disks;
3007 struct bio *return_bi = NULL;
3008 int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx;
3009 struct stripe_head_state s;
3010 struct r6_state r6s;
3011 struct r5dev *dev, *pdev, *qdev;
3012 mdk_rdev_t *blocked_rdev = NULL;
3014 pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
3015 "pd_idx=%d, qd_idx=%d\n",
3016 (unsigned long long)sh->sector, sh->state,
3017 atomic_read(&sh->count), pd_idx, qd_idx);
3018 memset(&s, 0, sizeof(s));
3020 spin_lock(&sh->lock);
3021 clear_bit(STRIPE_HANDLE, &sh->state);
3022 clear_bit(STRIPE_DELAYED, &sh->state);
3024 s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
3025 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
3026 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
3027 /* Now to look around and see what can be done */
3030 for (i=disks; i--; ) {
3033 clear_bit(R5_Insync, &dev->flags);
3035 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3036 i, dev->flags, dev->toread, dev->towrite, dev->written);
3037 /* maybe we can reply to a read */
3038 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
3039 struct bio *rbi, *rbi2;
3040 pr_debug("Return read for disc %d\n", i);
3041 spin_lock_irq(&conf->device_lock);
3044 if (test_and_clear_bit(R5_Overlap, &dev->flags))
3045 wake_up(&conf->wait_for_overlap);
3046 spin_unlock_irq(&conf->device_lock);
3047 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
3048 copy_data(0, rbi, dev->page, dev->sector);
3049 rbi2 = r5_next_bio(rbi, dev->sector);
3050 spin_lock_irq(&conf->device_lock);
3051 if (!raid5_dec_bi_phys_segments(rbi)) {
3052 rbi->bi_next = return_bi;
3055 spin_unlock_irq(&conf->device_lock);
3060 /* now count some things */
3061 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
3062 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;
3069 if (!test_bit(R5_OVERWRITE, &dev->flags))
3074 rdev = rcu_dereference(conf->disks[i].rdev);
3075 if (blocked_rdev == NULL &&
3076 rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
3077 blocked_rdev = rdev;
3078 atomic_inc(&rdev->nr_pending);
3080 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
3081 /* The ReadError flag will just be confusing now */
3082 clear_bit(R5_ReadError, &dev->flags);
3083 clear_bit(R5_ReWrite, &dev->flags);
3085 if (!rdev || !test_bit(In_sync, &rdev->flags)
3086 || test_bit(R5_ReadError, &dev->flags)) {
3088 r6s.failed_num[s.failed] = i;
3091 set_bit(R5_Insync, &dev->flags);
3095 if (unlikely(blocked_rdev)) {
3096 if (s.syncing || s.expanding || s.expanded ||
3097 s.to_write || s.written) {
3098 set_bit(STRIPE_HANDLE, &sh->state);
3101 /* There is nothing for the blocked_rdev to block */
3102 rdev_dec_pending(blocked_rdev, conf->mddev);
3103 blocked_rdev = NULL;
3106 pr_debug("locked=%d uptodate=%d to_read=%d"
3107 " to_write=%d failed=%d failed_num=%d,%d\n",
3108 s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
3109 r6s.failed_num[0], r6s.failed_num[1]);
3110 /* check if the array has lost >2 devices and, if so, some requests
3111 * might need to be failed
3113 if (s.failed > 2 && s.to_read+s.to_write+s.written)
3114 handle_failed_stripe(conf, sh, &s, disks, &return_bi);
3115 if (s.failed > 2 && s.syncing) {
3116 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
3117 clear_bit(STRIPE_SYNCING, &sh->state);
3122 * might be able to return some write requests if the parity blocks
3123 * are safe, or on a failed drive
3125 pdev = &sh->dev[pd_idx];
3126 r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx)
3127 || (s.failed >= 2 && r6s.failed_num[1] == pd_idx);
3128 qdev = &sh->dev[qd_idx];
3129 r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == qd_idx)
3130 || (s.failed >= 2 && r6s.failed_num[1] == qd_idx);
3133 ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
3134 && !test_bit(R5_LOCKED, &pdev->flags)
3135 && test_bit(R5_UPTODATE, &pdev->flags)))) &&
3136 ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
3137 && !test_bit(R5_LOCKED, &qdev->flags)
3138 && test_bit(R5_UPTODATE, &qdev->flags)))))
3139 handle_stripe_clean_event(conf, sh, disks, &return_bi);
3141 /* Now we might consider reading some blocks, either to check/generate
3142 * parity, or to satisfy requests
3143 * or to load a block that is being partially written.
3145 if (s.to_read || s.non_overwrite || (s.to_write && s.failed) ||
3146 (s.syncing && (s.uptodate < disks)) || s.expanding)
3147 handle_stripe_fill6(sh, &s, &r6s, disks);
3149 /* now to consider writing and what else, if anything should be read */
3151 handle_stripe_dirtying6(conf, sh, &s, &r6s, disks);
3153 /* maybe we need to check and possibly fix the parity for this stripe
3154 * Any reads will already have been scheduled, so we just see if enough
3157 if (s.syncing && s.locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state))
3158 handle_parity_checks6(conf, sh, &s, &r6s, tmp_page, disks);
3160 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
3161 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
3162 clear_bit(STRIPE_SYNCING, &sh->state);
3165 /* If the failed drives are just a ReadError, then we might need
3166 * to progress the repair/check process
3168 if (s.failed <= 2 && !conf->mddev->ro)
3169 for (i = 0; i < s.failed; i++) {
3170 dev = &sh->dev[r6s.failed_num[i]];
3171 if (test_bit(R5_ReadError, &dev->flags)
3172 && !test_bit(R5_LOCKED, &dev->flags)
3173 && test_bit(R5_UPTODATE, &dev->flags)
3175 if (!test_bit(R5_ReWrite, &dev->flags)) {
3176 set_bit(R5_Wantwrite, &dev->flags);
3177 set_bit(R5_ReWrite, &dev->flags);
3178 set_bit(R5_LOCKED, &dev->flags);
3180 /* let's read it back */
3181 set_bit(R5_Wantread, &dev->flags);
3182 set_bit(R5_LOCKED, &dev->flags);
3187 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
3188 struct stripe_head *sh2
3189 = get_active_stripe(conf, sh->sector, 1, 1);
3190 if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) {
3191 /* sh cannot be written until sh2 has been read.
3192 * so arrange for sh to be delayed a little
3194 set_bit(STRIPE_DELAYED, &sh->state);
3195 set_bit(STRIPE_HANDLE, &sh->state);
3196 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
3198 atomic_inc(&conf->preread_active_stripes);
3199 release_stripe(sh2);
3203 release_stripe(sh2);
3205 /* Need to write out all blocks after computing P&Q */
3206 sh->disks = conf->raid_disks;
3207 stripe_set_idx(sh->sector, conf, 0, sh);
3208 compute_parity6(sh, RECONSTRUCT_WRITE);
3209 for (i = conf->raid_disks ; i-- ; ) {
3210 set_bit(R5_LOCKED, &sh->dev[i].flags);
3212 set_bit(R5_Wantwrite, &sh->dev[i].flags);
3214 clear_bit(STRIPE_EXPANDING, &sh->state);
3215 } else if (s.expanded) {
3216 clear_bit(STRIPE_EXPAND_READY, &sh->state);
3217 atomic_dec(&conf->reshape_stripes);
3218 wake_up(&conf->wait_for_overlap);
3219 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
3222 if (s.expanding && s.locked == 0 &&
3223 !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
3224 handle_stripe_expansion(conf, sh, &r6s);
3227 spin_unlock(&sh->lock);
3229 /* wait for this device to become unblocked */
3230 if (unlikely(blocked_rdev))
3231 md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
3235 return_io(return_bi);
3237 return blocked_rdev == NULL;
3240 /* returns true if the stripe was handled */
3241 static bool handle_stripe(struct stripe_head *sh, struct page *tmp_page)
3243 if (sh->raid_conf->level == 6)
3244 return handle_stripe6(sh, tmp_page);
3246 return handle_stripe5(sh);
3251 static void raid5_activate_delayed(raid5_conf_t *conf)
3253 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
3254 while (!list_empty(&conf->delayed_list)) {
3255 struct list_head *l = conf->delayed_list.next;
3256 struct stripe_head *sh;
3257 sh = list_entry(l, struct stripe_head, lru);
3259 clear_bit(STRIPE_DELAYED, &sh->state);
3260 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3261 atomic_inc(&conf->preread_active_stripes);
3262 list_add_tail(&sh->lru, &conf->hold_list);
3265 blk_plug_device(conf->mddev->queue);
3268 static void activate_bit_delay(raid5_conf_t *conf)
3270 /* device_lock is held */
3271 struct list_head head;
3272 list_add(&head, &conf->bitmap_list);
3273 list_del_init(&conf->bitmap_list);
3274 while (!list_empty(&head)) {
3275 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
3276 list_del_init(&sh->lru);
3277 atomic_inc(&sh->count);
3278 __release_stripe(conf, sh);
3282 static void unplug_slaves(mddev_t *mddev)
3284 raid5_conf_t *conf = mddev_to_conf(mddev);
3288 for (i=0; i<mddev->raid_disks; i++) {
3289 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
3290 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
3291 struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
3293 atomic_inc(&rdev->nr_pending);
3296 blk_unplug(r_queue);
3298 rdev_dec_pending(rdev, mddev);
3305 static void raid5_unplug_device(struct request_queue *q)
3307 mddev_t *mddev = q->queuedata;
3308 raid5_conf_t *conf = mddev_to_conf(mddev);
3309 unsigned long flags;
3311 spin_lock_irqsave(&conf->device_lock, flags);
3313 if (blk_remove_plug(q)) {
3315 raid5_activate_delayed(conf);
3317 md_wakeup_thread(mddev->thread);
3319 spin_unlock_irqrestore(&conf->device_lock, flags);
3321 unplug_slaves(mddev);
3324 static int raid5_congested(void *data, int bits)
3326 mddev_t *mddev = data;
3327 raid5_conf_t *conf = mddev_to_conf(mddev);
3329 /* No difference between reads and writes. Just check
3330 * how busy the stripe_cache is
3332 if (conf->inactive_blocked)
3336 if (list_empty_careful(&conf->inactive_list))
3342 /* We want read requests to align with chunks where possible,
3343 * but write requests don't need to.
3345 static int raid5_mergeable_bvec(struct request_queue *q,
3346 struct bvec_merge_data *bvm,
3347 struct bio_vec *biovec)
3349 mddev_t *mddev = q->queuedata;
3350 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3352 unsigned int chunk_sectors = mddev->chunk_size >> 9;
3353 unsigned int bio_sectors = bvm->bi_size >> 9;
3355 if ((bvm->bi_rw & 1) == WRITE)
3356 return biovec->bv_len; /* always allow writes to be mergeable */
3358 if (mddev->new_chunk < mddev->chunk_size)
3359 chunk_sectors = mddev->new_chunk >> 9;
3360 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
3361 if (max < 0) max = 0;
3362 if (max <= biovec->bv_len && bio_sectors == 0)
3363 return biovec->bv_len;
3369 static int in_chunk_boundary(mddev_t *mddev, struct bio *bio)
3371 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3372 unsigned int chunk_sectors = mddev->chunk_size >> 9;
3373 unsigned int bio_sectors = bio->bi_size >> 9;
3375 if (mddev->new_chunk < mddev->chunk_size)
3376 chunk_sectors = mddev->new_chunk >> 9;
3377 return chunk_sectors >=
3378 ((sector & (chunk_sectors - 1)) + bio_sectors);
3382 * add bio to the retry LIFO ( in O(1) ... we are in interrupt )
3383 * later sampled by raid5d.
3385 static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf)
3387 unsigned long flags;
3389 spin_lock_irqsave(&conf->device_lock, flags);
3391 bi->bi_next = conf->retry_read_aligned_list;
3392 conf->retry_read_aligned_list = bi;
3394 spin_unlock_irqrestore(&conf->device_lock, flags);
3395 md_wakeup_thread(conf->mddev->thread);
3399 static struct bio *remove_bio_from_retry(raid5_conf_t *conf)
3403 bi = conf->retry_read_aligned;
3405 conf->retry_read_aligned = NULL;
3408 bi = conf->retry_read_aligned_list;
3410 conf->retry_read_aligned_list = bi->bi_next;
3413 * this sets the active strip count to 1 and the processed
3414 * strip count to zero (upper 8 bits)
3416 bi->bi_phys_segments = 1; /* biased count of active stripes */
3424 * The "raid5_align_endio" should check if the read succeeded and if it
3425 * did, call bio_endio on the original bio (having bio_put the new bio
3427 * If the read failed..
3429 static void raid5_align_endio(struct bio *bi, int error)
3431 struct bio* raid_bi = bi->bi_private;
3434 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3439 mddev = raid_bi->bi_bdev->bd_disk->queue->queuedata;
3440 conf = mddev_to_conf(mddev);
3441 rdev = (void*)raid_bi->bi_next;
3442 raid_bi->bi_next = NULL;
3444 rdev_dec_pending(rdev, conf->mddev);
3446 if (!error && uptodate) {
3447 bio_endio(raid_bi, 0);
3448 if (atomic_dec_and_test(&conf->active_aligned_reads))
3449 wake_up(&conf->wait_for_stripe);
3454 pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3456 add_bio_to_retry(raid_bi, conf);
3459 static int bio_fits_rdev(struct bio *bi)
3461 struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3463 if ((bi->bi_size>>9) > q->max_sectors)
3465 blk_recount_segments(q, bi);
3466 if (bi->bi_phys_segments > q->max_phys_segments)
3469 if (q->merge_bvec_fn)
3470 /* it's too hard to apply the merge_bvec_fn at this stage,
3479 static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio)
3481 mddev_t *mddev = q->queuedata;
3482 raid5_conf_t *conf = mddev_to_conf(mddev);
3483 unsigned int dd_idx;
3484 struct bio* align_bi;
3487 if (!in_chunk_boundary(mddev, raid_bio)) {
3488 pr_debug("chunk_aligned_read : non aligned\n");
3492 * use bio_clone to make a copy of the bio
3494 align_bi = bio_clone(raid_bio, GFP_NOIO);
3498 * set bi_end_io to a new function, and set bi_private to the
3501 align_bi->bi_end_io = raid5_align_endio;
3502 align_bi->bi_private = raid_bio;
3506 align_bi->bi_sector = raid5_compute_sector(conf, raid_bio->bi_sector,
3511 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
3512 if (rdev && test_bit(In_sync, &rdev->flags)) {
3513 atomic_inc(&rdev->nr_pending);
3515 raid_bio->bi_next = (void*)rdev;
3516 align_bi->bi_bdev = rdev->bdev;
3517 align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);
3518 align_bi->bi_sector += rdev->data_offset;
3520 if (!bio_fits_rdev(align_bi)) {
3521 /* too big in some way */
3523 rdev_dec_pending(rdev, mddev);
3527 spin_lock_irq(&conf->device_lock);
3528 wait_event_lock_irq(conf->wait_for_stripe,
3530 conf->device_lock, /* nothing */);
3531 atomic_inc(&conf->active_aligned_reads);
3532 spin_unlock_irq(&conf->device_lock);
3534 generic_make_request(align_bi);
3543 /* __get_priority_stripe - get the next stripe to process
3545 * Full stripe writes are allowed to pass preread active stripes up until
3546 * the bypass_threshold is exceeded. In general the bypass_count
3547 * increments when the handle_list is handled before the hold_list; however, it
3548 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
3549 * stripe with in flight i/o. The bypass_count will be reset when the
3550 * head of the hold_list has changed, i.e. the head was promoted to the
3553 static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf)
3555 struct stripe_head *sh;
3557 pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
3559 list_empty(&conf->handle_list) ? "empty" : "busy",
3560 list_empty(&conf->hold_list) ? "empty" : "busy",
3561 atomic_read(&conf->pending_full_writes), conf->bypass_count);
3563 if (!list_empty(&conf->handle_list)) {
3564 sh = list_entry(conf->handle_list.next, typeof(*sh), lru);
3566 if (list_empty(&conf->hold_list))
3567 conf->bypass_count = 0;
3568 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
3569 if (conf->hold_list.next == conf->last_hold)
3570 conf->bypass_count++;
3572 conf->last_hold = conf->hold_list.next;
3573 conf->bypass_count -= conf->bypass_threshold;
3574 if (conf->bypass_count < 0)
3575 conf->bypass_count = 0;
3578 } else if (!list_empty(&conf->hold_list) &&
3579 ((conf->bypass_threshold &&
3580 conf->bypass_count > conf->bypass_threshold) ||
3581 atomic_read(&conf->pending_full_writes) == 0)) {
3582 sh = list_entry(conf->hold_list.next,
3584 conf->bypass_count -= conf->bypass_threshold;
3585 if (conf->bypass_count < 0)
3586 conf->bypass_count = 0;
3590 list_del_init(&sh->lru);
3591 atomic_inc(&sh->count);
3592 BUG_ON(atomic_read(&sh->count) != 1);
3596 static int make_request(struct request_queue *q, struct bio * bi)
3598 mddev_t *mddev = q->queuedata;
3599 raid5_conf_t *conf = mddev_to_conf(mddev);
3601 sector_t new_sector;
3602 sector_t logical_sector, last_sector;
3603 struct stripe_head *sh;
3604 const int rw = bio_data_dir(bi);
3607 if (unlikely(bio_barrier(bi))) {
3608 bio_endio(bi, -EOPNOTSUPP);
3612 md_write_start(mddev, bi);
3614 cpu = part_stat_lock();
3615 part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
3616 part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
3621 mddev->reshape_position == MaxSector &&
3622 chunk_aligned_read(q,bi))
3625 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
3626 last_sector = bi->bi_sector + (bi->bi_size>>9);
3628 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
3630 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
3632 int disks, data_disks;
3637 disks = conf->raid_disks;
3638 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
3639 if (unlikely(conf->reshape_progress != MaxSector)) {
3640 /* spinlock is needed as reshape_progress may be
3641 * 64bit on a 32bit platform, and so it might be
3642 * possible to see a half-updated value
3643 * Ofcourse reshape_progress could change after
3644 * the lock is dropped, so once we get a reference
3645 * to the stripe that we think it is, we will have
3648 spin_lock_irq(&conf->device_lock);
3649 if (mddev->delta_disks < 0
3650 ? logical_sector < conf->reshape_progress
3651 : logical_sector >= conf->reshape_progress) {
3652 disks = conf->previous_raid_disks;
3655 if (mddev->delta_disks < 0
3656 ? logical_sector < conf->reshape_safe
3657 : logical_sector >= conf->reshape_safe) {
3658 spin_unlock_irq(&conf->device_lock);
3663 spin_unlock_irq(&conf->device_lock);
3665 data_disks = disks - conf->max_degraded;
3667 new_sector = raid5_compute_sector(conf, logical_sector,
3670 pr_debug("raid5: make_request, sector %llu logical %llu\n",
3671 (unsigned long long)new_sector,
3672 (unsigned long long)logical_sector);
3674 sh = get_active_stripe(conf, new_sector, previous,
3675 (bi->bi_rw&RWA_MASK));
3677 if (unlikely(previous)) {
3678 /* expansion might have moved on while waiting for a
3679 * stripe, so we must do the range check again.
3680 * Expansion could still move past after this
3681 * test, but as we are holding a reference to
3682 * 'sh', we know that if that happens,
3683 * STRIPE_EXPANDING will get set and the expansion
3684 * won't proceed until we finish with the stripe.
3687 spin_lock_irq(&conf->device_lock);
3688 if (mddev->delta_disks < 0
3689 ? logical_sector >= conf->reshape_progress
3690 : logical_sector < conf->reshape_progress)
3691 /* mismatch, need to try again */
3693 spin_unlock_irq(&conf->device_lock);
3699 /* FIXME what if we get a false positive because these
3700 * are being updated.
3702 if (logical_sector >= mddev->suspend_lo &&
3703 logical_sector < mddev->suspend_hi) {
3709 if (test_bit(STRIPE_EXPANDING, &sh->state) ||
3710 !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
3711 /* Stripe is busy expanding or
3712 * add failed due to overlap. Flush everything
3715 raid5_unplug_device(mddev->queue);
3720 finish_wait(&conf->wait_for_overlap, &w);
3721 set_bit(STRIPE_HANDLE, &sh->state);
3722 clear_bit(STRIPE_DELAYED, &sh->state);
3725 /* cannot get stripe for read-ahead, just give-up */
3726 clear_bit(BIO_UPTODATE, &bi->bi_flags);
3727 finish_wait(&conf->wait_for_overlap, &w);
3732 spin_lock_irq(&conf->device_lock);
3733 remaining = raid5_dec_bi_phys_segments(bi);
3734 spin_unlock_irq(&conf->device_lock);
3735 if (remaining == 0) {
3738 md_write_end(mddev);
3745 static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks);
3747 static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped)
3749 /* reshaping is quite different to recovery/resync so it is
3750 * handled quite separately ... here.
3752 * On each call to sync_request, we gather one chunk worth of
3753 * destination stripes and flag them as expanding.
3754 * Then we find all the source stripes and request reads.
3755 * As the reads complete, handle_stripe will copy the data
3756 * into the destination stripe and release that stripe.
3758 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
3759 struct stripe_head *sh;
3760 sector_t first_sector, last_sector;
3761 int raid_disks = conf->previous_raid_disks;
3762 int data_disks = raid_disks - conf->max_degraded;
3763 int new_data_disks = conf->raid_disks - conf->max_degraded;
3766 sector_t writepos, readpos, safepos;
3767 sector_t stripe_addr;
3768 int reshape_sectors;
3769 struct list_head stripes;
3771 if (sector_nr == 0) {
3772 /* If restarting in the middle, skip the initial sectors */
3773 if (mddev->delta_disks < 0 &&
3774 conf->reshape_progress < raid5_size(mddev, 0, 0)) {
3775 sector_nr = raid5_size(mddev, 0, 0)
3776 - conf->reshape_progress;
3777 } else if (mddev->delta_disks > 0 &&
3778 conf->reshape_progress > 0)
3779 sector_nr = conf->reshape_progress;
3780 sector_div(sector_nr, new_data_disks);
3787 /* We need to process a full chunk at a time.
3788 * If old and new chunk sizes differ, we need to process the
3791 if (mddev->new_chunk > mddev->chunk_size)
3792 reshape_sectors = mddev->new_chunk / 512;
3794 reshape_sectors = mddev->chunk_size / 512;
3796 /* we update the metadata when there is more than 3Meg
3797 * in the block range (that is rather arbitrary, should
3798 * probably be time based) or when the data about to be
3799 * copied would over-write the source of the data at
3800 * the front of the range.
3801 * i.e. one new_stripe along from reshape_progress new_maps
3802 * to after where reshape_safe old_maps to
3804 writepos = conf->reshape_progress;
3805 sector_div(writepos, new_data_disks);
3806 readpos = conf->reshape_progress;
3807 sector_div(readpos, data_disks);
3808 safepos = conf->reshape_safe;
3809 sector_div(safepos, data_disks);
3810 if (mddev->delta_disks < 0) {
3811 writepos -= reshape_sectors;
3812 readpos += reshape_sectors;
3813 safepos += reshape_sectors;
3815 writepos += reshape_sectors;
3816 readpos -= reshape_sectors;
3817 safepos -= reshape_sectors;
3820 /* 'writepos' is the most advanced device address we might write.
3821 * 'readpos' is the least advanced device address we might read.
3822 * 'safepos' is the least address recorded in the metadata as having
3824 * If 'readpos' is behind 'writepos', then there is no way that we can
3825 * ensure safety in the face of a crash - that must be done by userspace
3826 * making a backup of the data. So in that case there is no particular
3827 * rush to update metadata.
3828 * Otherwise if 'safepos' is behind 'writepos', then we really need to
3829 * update the metadata to advance 'safepos' to match 'readpos' so that
3830 * we can be safe in the event of a crash.
3831 * So we insist on updating metadata if safepos is behind writepos and
3832 * readpos is beyond writepos.
3833 * In any case, update the metadata every 10 seconds.
3834 * Maybe that number should be configurable, but I'm not sure it is
3835 * worth it.... maybe it could be a multiple of safemode_delay???
3837 if ((mddev->delta_disks < 0
3838 ? (safepos > writepos && readpos < writepos)
3839 : (safepos < writepos && readpos > writepos)) ||
3840 time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
3841 /* Cannot proceed until we've updated the superblock... */
3842 wait_event(conf->wait_for_overlap,
3843 atomic_read(&conf->reshape_stripes)==0);
3844 mddev->reshape_position = conf->reshape_progress;
3845 conf->reshape_checkpoint = jiffies;
3846 set_bit(MD_CHANGE_DEVS, &mddev->flags);
3847 md_wakeup_thread(mddev->thread);
3848 wait_event(mddev->sb_wait, mddev->flags == 0 ||
3849 kthread_should_stop());
3850 spin_lock_irq(&conf->device_lock);
3851 conf->reshape_safe = mddev->reshape_position;
3852 spin_unlock_irq(&conf->device_lock);
3853 wake_up(&conf->wait_for_overlap);
3856 if (mddev->delta_disks < 0) {
3857 BUG_ON(conf->reshape_progress == 0);
3858 stripe_addr = writepos;
3859 BUG_ON((mddev->dev_sectors &
3860 ~((sector_t)reshape_sectors - 1))
3861 - reshape_sectors - stripe_addr
3864 BUG_ON(writepos != sector_nr + reshape_sectors);
3865 stripe_addr = sector_nr;
3867 INIT_LIST_HEAD(&stripes);
3868 for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
3871 sh = get_active_stripe(conf, stripe_addr+i, 0, 0);
3872 set_bit(STRIPE_EXPANDING, &sh->state);
3873 atomic_inc(&conf->reshape_stripes);
3874 /* If any of this stripe is beyond the end of the old
3875 * array, then we need to zero those blocks
3877 for (j=sh->disks; j--;) {
3879 if (j == sh->pd_idx)
3881 if (conf->level == 6 &&
3884 s = compute_blocknr(sh, j, 0);
3885 if (s < raid5_size(mddev, 0, 0)) {
3889 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
3890 set_bit(R5_Expanded, &sh->dev[j].flags);
3891 set_bit(R5_UPTODATE, &sh->dev[j].flags);
3894 set_bit(STRIPE_EXPAND_READY, &sh->state);
3895 set_bit(STRIPE_HANDLE, &sh->state);
3897 list_add(&sh->lru, &stripes);
3899 spin_lock_irq(&conf->device_lock);
3900 if (mddev->delta_disks < 0)
3901 conf->reshape_progress -= reshape_sectors * new_data_disks;
3903 conf->reshape_progress += reshape_sectors * new_data_disks;
3904 spin_unlock_irq(&conf->device_lock);
3905 /* Ok, those stripe are ready. We can start scheduling
3906 * reads on the source stripes.
3907 * The source stripes are determined by mapping the first and last
3908 * block on the destination stripes.
3911 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
3914 raid5_compute_sector(conf, ((stripe_addr+conf->chunk_size/512)
3915 *(new_data_disks) - 1),
3917 if (last_sector >= mddev->dev_sectors)
3918 last_sector = mddev->dev_sectors - 1;
3919 while (first_sector <= last_sector) {
3920 sh = get_active_stripe(conf, first_sector, 1, 0);
3921 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
3922 set_bit(STRIPE_HANDLE, &sh->state);
3924 first_sector += STRIPE_SECTORS;
3926 /* Now that the sources are clearly marked, we can release
3927 * the destination stripes
3929 while (!list_empty(&stripes)) {
3930 sh = list_entry(stripes.next, struct stripe_head, lru);
3931 list_del_init(&sh->lru);
3934 /* If this takes us to the resync_max point where we have to pause,
3935 * then we need to write out the superblock.
3937 sector_nr += reshape_sectors;
3938 if (sector_nr >= mddev->resync_max) {
3939 /* Cannot proceed until we've updated the superblock... */
3940 wait_event(conf->wait_for_overlap,
3941 atomic_read(&conf->reshape_stripes) == 0);
3942 mddev->reshape_position = conf->reshape_progress;
3943 conf->reshape_checkpoint = jiffies;
3944 set_bit(MD_CHANGE_DEVS, &mddev->flags);
3945 md_wakeup_thread(mddev->thread);
3946 wait_event(mddev->sb_wait,
3947 !test_bit(MD_CHANGE_DEVS, &mddev->flags)
3948 || kthread_should_stop());
3949 spin_lock_irq(&conf->device_lock);
3950 conf->reshape_safe = mddev->reshape_position;
3951 spin_unlock_irq(&conf->device_lock);
3952 wake_up(&conf->wait_for_overlap);
3954 return reshape_sectors;
3957 /* FIXME go_faster isn't used */
3958 static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
3960 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
3961 struct stripe_head *sh;
3962 sector_t max_sector = mddev->dev_sectors;
3964 int still_degraded = 0;
3967 if (sector_nr >= max_sector) {
3968 /* just being told to finish up .. nothing much to do */
3969 unplug_slaves(mddev);
3971 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
3976 if (mddev->curr_resync < max_sector) /* aborted */
3977 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
3979 else /* completed sync */
3981 bitmap_close_sync(mddev->bitmap);
3986 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3987 return reshape_request(mddev, sector_nr, skipped);
3989 /* No need to check resync_max as we never do more than one
3990 * stripe, and as resync_max will always be on a chunk boundary,
3991 * if the check in md_do_sync didn't fire, there is no chance
3992 * of overstepping resync_max here
3995 /* if there is too many failed drives and we are trying
3996 * to resync, then assert that we are finished, because there is
3997 * nothing we can do.
3999 if (mddev->degraded >= conf->max_degraded &&
4000 test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
4001 sector_t rv = mddev->dev_sectors - sector_nr;
4005 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
4006 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
4007 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
4008 /* we can skip this block, and probably more */
4009 sync_blocks /= STRIPE_SECTORS;
4011 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
4015 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
4017 sh = get_active_stripe(conf, sector_nr, 0, 1);
4019 sh = get_active_stripe(conf, sector_nr, 0, 0);
4020 /* make sure we don't swamp the stripe cache if someone else
4021 * is trying to get access
4023 schedule_timeout_uninterruptible(1);
4025 /* Need to check if array will still be degraded after recovery/resync
4026 * We don't need to check the 'failed' flag as when that gets set,
4029 for (i=0; i<mddev->raid_disks; i++)
4030 if (conf->disks[i].rdev == NULL)
4033 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
4035 spin_lock(&sh->lock);
4036 set_bit(STRIPE_SYNCING, &sh->state);
4037 clear_bit(STRIPE_INSYNC, &sh->state);
4038 spin_unlock(&sh->lock);
4040 /* wait for any blocked device to be handled */
4041 while(unlikely(!handle_stripe(sh, NULL)))
4045 return STRIPE_SECTORS;
4048 static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
4050 /* We may not be able to submit a whole bio at once as there
4051 * may not be enough stripe_heads available.
4052 * We cannot pre-allocate enough stripe_heads as we may need
4053 * more than exist in the cache (if we allow ever large chunks).
4054 * So we do one stripe head at a time and record in
4055 * ->bi_hw_segments how many have been done.
4057 * We *know* that this entire raid_bio is in one chunk, so
4058 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
4060 struct stripe_head *sh;
4062 sector_t sector, logical_sector, last_sector;
4067 logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
4068 sector = raid5_compute_sector(conf, logical_sector,
4070 last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);
4072 for (; logical_sector < last_sector;
4073 logical_sector += STRIPE_SECTORS,
4074 sector += STRIPE_SECTORS,
4077 if (scnt < raid5_bi_hw_segments(raid_bio))
4078 /* already done this stripe */
4081 sh = get_active_stripe(conf, sector, 0, 1);
4084 /* failed to get a stripe - must wait */
4085 raid5_set_bi_hw_segments(raid_bio, scnt);
4086 conf->retry_read_aligned = raid_bio;
4090 set_bit(R5_ReadError, &sh->dev[dd_idx].flags);
4091 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
4093 raid5_set_bi_hw_segments(raid_bio, scnt);
4094 conf->retry_read_aligned = raid_bio;
4098 handle_stripe(sh, NULL);
4102 spin_lock_irq(&conf->device_lock);
4103 remaining = raid5_dec_bi_phys_segments(raid_bio);
4104 spin_unlock_irq(&conf->device_lock);
4106 bio_endio(raid_bio, 0);
4107 if (atomic_dec_and_test(&conf->active_aligned_reads))
4108 wake_up(&conf->wait_for_stripe);
4115 * This is our raid5 kernel thread.
4117 * We scan the hash table for stripes which can be handled now.
4118 * During the scan, completed stripes are saved for us by the interrupt
4119 * handler, so that they will not have to wait for our next wakeup.
4121 static void raid5d(mddev_t *mddev)
4123 struct stripe_head *sh;
4124 raid5_conf_t *conf = mddev_to_conf(mddev);
4127 pr_debug("+++ raid5d active\n");
4129 md_check_recovery(mddev);
4132 spin_lock_irq(&conf->device_lock);
4136 if (conf->seq_flush != conf->seq_write) {
4137 int seq = conf->seq_flush;
4138 spin_unlock_irq(&conf->device_lock);
4139 bitmap_unplug(mddev->bitmap);
4140 spin_lock_irq(&conf->device_lock);
4141 conf->seq_write = seq;
4142 activate_bit_delay(conf);
4145 while ((bio = remove_bio_from_retry(conf))) {
4147 spin_unlock_irq(&conf->device_lock);
4148 ok = retry_aligned_read(conf, bio);
4149 spin_lock_irq(&conf->device_lock);
4155 sh = __get_priority_stripe(conf);
4159 spin_unlock_irq(&conf->device_lock);
4162 handle_stripe(sh, conf->spare_page);
4165 spin_lock_irq(&conf->device_lock);
4167 pr_debug("%d stripes handled\n", handled);
4169 spin_unlock_irq(&conf->device_lock);
4171 async_tx_issue_pending_all();
4172 unplug_slaves(mddev);
4174 pr_debug("--- raid5d inactive\n");
4178 raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
4180 raid5_conf_t *conf = mddev_to_conf(mddev);
4182 return sprintf(page, "%d\n", conf->max_nr_stripes);
4188 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
4190 raid5_conf_t *conf = mddev_to_conf(mddev);
4194 if (len >= PAGE_SIZE)
4199 if (strict_strtoul(page, 10, &new))
4201 if (new <= 16 || new > 32768)
4203 while (new < conf->max_nr_stripes) {
4204 if (drop_one_stripe(conf))
4205 conf->max_nr_stripes--;
4209 err = md_allow_write(mddev);
4212 while (new > conf->max_nr_stripes) {
4213 if (grow_one_stripe(conf))
4214 conf->max_nr_stripes++;
4220 static struct md_sysfs_entry
4221 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
4222 raid5_show_stripe_cache_size,
4223 raid5_store_stripe_cache_size);
4226 raid5_show_preread_threshold(mddev_t *mddev, char *page)
4228 raid5_conf_t *conf = mddev_to_conf(mddev);
4230 return sprintf(page, "%d\n", conf->bypass_threshold);
4236 raid5_store_preread_threshold(mddev_t *mddev, const char *page, size_t len)
4238 raid5_conf_t *conf = mddev_to_conf(mddev);
4240 if (len >= PAGE_SIZE)
4245 if (strict_strtoul(page, 10, &new))
4247 if (new > conf->max_nr_stripes)
4249 conf->bypass_threshold = new;
4253 static struct md_sysfs_entry
4254 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
4256 raid5_show_preread_threshold,
4257 raid5_store_preread_threshold);
4260 stripe_cache_active_show(mddev_t *mddev, char *page)
4262 raid5_conf_t *conf = mddev_to_conf(mddev);
4264 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
4269 static struct md_sysfs_entry
4270 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4272 static struct attribute *raid5_attrs[] = {
4273 &raid5_stripecache_size.attr,
4274 &raid5_stripecache_active.attr,
4275 &raid5_preread_bypass_threshold.attr,
4278 static struct attribute_group raid5_attrs_group = {
4280 .attrs = raid5_attrs,
4284 raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)
4286 raid5_conf_t *conf = mddev_to_conf(mddev);
4289 sectors = mddev->dev_sectors;
4291 /* size is defined by the smallest of previous and new size */
4292 if (conf->raid_disks < conf->previous_raid_disks)
4293 raid_disks = conf->raid_disks;
4295 raid_disks = conf->previous_raid_disks;
4298 sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
4299 sectors &= ~((sector_t)mddev->new_chunk/512 - 1);
4300 return sectors * (raid_disks - conf->max_degraded);
4303 static raid5_conf_t *setup_conf(mddev_t *mddev)
4306 int raid_disk, memory;
4308 struct disk_info *disk;
4310 if (mddev->new_level != 5
4311 && mddev->new_level != 4
4312 && mddev->new_level != 6) {
4313 printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n",
4314 mdname(mddev), mddev->new_level);
4315 return ERR_PTR(-EIO);
4317 if ((mddev->new_level == 5
4318 && !algorithm_valid_raid5(mddev->new_layout)) ||
4319 (mddev->new_level == 6
4320 && !algorithm_valid_raid6(mddev->new_layout))) {
4321 printk(KERN_ERR "raid5: %s: layout %d not supported\n",
4322 mdname(mddev), mddev->new_layout);
4323 return ERR_PTR(-EIO);
4325 if (mddev->new_level == 6 && mddev->raid_disks < 4) {
4326 printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
4327 mdname(mddev), mddev->raid_disks);
4328 return ERR_PTR(-EINVAL);
4331 if (!mddev->new_chunk || mddev->new_chunk % PAGE_SIZE) {
4332 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
4333 mddev->new_chunk, mdname(mddev));
4334 return ERR_PTR(-EINVAL);
4337 conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL);
4341 conf->raid_disks = mddev->raid_disks;
4342 if (mddev->reshape_position == MaxSector)
4343 conf->previous_raid_disks = mddev->raid_disks;
4345 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
4347 conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
4352 conf->mddev = mddev;
4354 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
4357 if (mddev->new_level == 6) {
4358 conf->spare_page = alloc_page(GFP_KERNEL);
4359 if (!conf->spare_page)
4362 spin_lock_init(&conf->device_lock);
4363 init_waitqueue_head(&conf->wait_for_stripe);
4364 init_waitqueue_head(&conf->wait_for_overlap);
4365 INIT_LIST_HEAD(&conf->handle_list);
4366 INIT_LIST_HEAD(&conf->hold_list);
4367 INIT_LIST_HEAD(&conf->delayed_list);
4368 INIT_LIST_HEAD(&conf->bitmap_list);
4369 INIT_LIST_HEAD(&conf->inactive_list);
4370 atomic_set(&conf->active_stripes, 0);
4371 atomic_set(&conf->preread_active_stripes, 0);
4372 atomic_set(&conf->active_aligned_reads, 0);
4373 conf->bypass_threshold = BYPASS_THRESHOLD;
4375 pr_debug("raid5: run(%s) called.\n", mdname(mddev));
4377 list_for_each_entry(rdev, &mddev->disks, same_set) {
4378 raid_disk = rdev->raid_disk;
4379 if (raid_disk >= conf->raid_disks
4382 disk = conf->disks + raid_disk;
4386 if (test_bit(In_sync, &rdev->flags)) {
4387 char b[BDEVNAME_SIZE];
4388 printk(KERN_INFO "raid5: device %s operational as raid"
4389 " disk %d\n", bdevname(rdev->bdev,b),
4392 /* Cannot rely on bitmap to complete recovery */
4396 conf->chunk_size = mddev->new_chunk;
4397 conf->level = mddev->new_level;
4398 if (conf->level == 6)
4399 conf->max_degraded = 2;
4401 conf->max_degraded = 1;
4402 conf->algorithm = mddev->new_layout;
4403 conf->max_nr_stripes = NR_STRIPES;
4404 conf->reshape_progress = mddev->reshape_position;
4405 if (conf->reshape_progress != MaxSector) {
4406 conf->prev_chunk = mddev->chunk_size;
4407 conf->prev_algo = mddev->layout;
4410 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
4411 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
4412 if (grow_stripes(conf, conf->max_nr_stripes)) {
4414 "raid5: couldn't allocate %dkB for buffers\n", memory);
4417 printk(KERN_INFO "raid5: allocated %dkB for %s\n",
4418 memory, mdname(mddev));
4420 conf->thread = md_register_thread(raid5d, mddev, "%s_raid5");
4421 if (!conf->thread) {
4423 "raid5: couldn't allocate thread for %s\n",
4432 shrink_stripes(conf);
4433 safe_put_page(conf->spare_page);
4435 kfree(conf->stripe_hashtbl);
4437 return ERR_PTR(-EIO);
4439 return ERR_PTR(-ENOMEM);
4442 static int run(mddev_t *mddev)
4445 int working_disks = 0;
4448 if (mddev->reshape_position != MaxSector) {
4449 /* Check that we can continue the reshape.
4450 * Currently only disks can change, it must
4451 * increase, and we must be past the point where
4452 * a stripe over-writes itself
4454 sector_t here_new, here_old;
4456 int max_degraded = (mddev->level == 6 ? 2 : 1);
4458 if (mddev->new_level != mddev->level) {
4459 printk(KERN_ERR "raid5: %s: unsupported reshape "
4460 "required - aborting.\n",
4464 old_disks = mddev->raid_disks - mddev->delta_disks;
4465 /* reshape_position must be on a new-stripe boundary, and one
4466 * further up in new geometry must map after here in old
4469 here_new = mddev->reshape_position;
4470 if (sector_div(here_new, (mddev->new_chunk>>9)*
4471 (mddev->raid_disks - max_degraded))) {
4472 printk(KERN_ERR "raid5: reshape_position not "
4473 "on a stripe boundary\n");
4476 /* here_new is the stripe we will write to */
4477 here_old = mddev->reshape_position;
4478 sector_div(here_old, (mddev->chunk_size>>9)*
4479 (old_disks-max_degraded));
4480 /* here_old is the first stripe that we might need to read
4482 if (here_new >= here_old) {
4483 /* Reading from the same stripe as writing to - bad */
4484 printk(KERN_ERR "raid5: reshape_position too early for "
4485 "auto-recovery - aborting.\n");
4488 printk(KERN_INFO "raid5: reshape will continue\n");
4489 /* OK, we should be able to continue; */
4491 BUG_ON(mddev->level != mddev->new_level);
4492 BUG_ON(mddev->layout != mddev->new_layout);
4493 BUG_ON(mddev->chunk_size != mddev->new_chunk);
4494 BUG_ON(mddev->delta_disks != 0);
4497 if (mddev->private == NULL)
4498 conf = setup_conf(mddev);
4500 conf = mddev->private;
4503 return PTR_ERR(conf);
4505 mddev->thread = conf->thread;
4506 conf->thread = NULL;
4507 mddev->private = conf;
4510 * 0 for a fully functional array, 1 or 2 for a degraded array.
4512 list_for_each_entry(rdev, &mddev->disks, same_set)
4513 if (rdev->raid_disk >= 0 &&
4514 test_bit(In_sync, &rdev->flags))
4517 mddev->degraded = conf->raid_disks - working_disks;
4519 if (mddev->degraded > conf->max_degraded) {
4520 printk(KERN_ERR "raid5: not enough operational devices for %s"
4521 " (%d/%d failed)\n",
4522 mdname(mddev), mddev->degraded, conf->raid_disks);
4526 /* device size must be a multiple of chunk size */
4527 mddev->dev_sectors &= ~(mddev->chunk_size / 512 - 1);
4528 mddev->resync_max_sectors = mddev->dev_sectors;
4530 if (mddev->degraded > 0 &&
4531 mddev->recovery_cp != MaxSector) {
4532 if (mddev->ok_start_degraded)
4534 "raid5: starting dirty degraded array: %s"
4535 "- data corruption possible.\n",
4539 "raid5: cannot start dirty degraded array for %s\n",
4545 if (mddev->degraded == 0)
4546 printk("raid5: raid level %d set %s active with %d out of %d"
4547 " devices, algorithm %d\n", conf->level, mdname(mddev),
4548 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
4551 printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
4552 " out of %d devices, algorithm %d\n", conf->level,
4553 mdname(mddev), mddev->raid_disks - mddev->degraded,
4554 mddev->raid_disks, mddev->new_layout);
4556 print_raid5_conf(conf);
4558 if (conf->reshape_progress != MaxSector) {
4559 printk("...ok start reshape thread\n");
4560 conf->reshape_safe = conf->reshape_progress;
4561 atomic_set(&conf->reshape_stripes, 0);
4562 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4563 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4564 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4565 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4566 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4570 /* read-ahead size must cover two whole stripes, which is
4571 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
4574 int data_disks = conf->previous_raid_disks - conf->max_degraded;
4575 int stripe = data_disks *
4576 (mddev->chunk_size / PAGE_SIZE);
4577 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
4578 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
4581 /* Ok, everything is just fine now */
4582 if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
4584 "raid5: failed to create sysfs attributes for %s\n",
4587 mddev->queue->queue_lock = &conf->device_lock;
4589 mddev->queue->unplug_fn = raid5_unplug_device;
4590 mddev->queue->backing_dev_info.congested_data = mddev;
4591 mddev->queue->backing_dev_info.congested_fn = raid5_congested;
4593 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
4595 blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
4599 md_unregister_thread(mddev->thread);
4600 mddev->thread = NULL;
4602 shrink_stripes(conf);
4603 print_raid5_conf(conf);
4604 safe_put_page(conf->spare_page);
4606 kfree(conf->stripe_hashtbl);
4609 mddev->private = NULL;
4610 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
4616 static int stop(mddev_t *mddev)
4618 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
4620 md_unregister_thread(mddev->thread);
4621 mddev->thread = NULL;
4622 shrink_stripes(conf);
4623 kfree(conf->stripe_hashtbl);
4624 mddev->queue->backing_dev_info.congested_fn = NULL;
4625 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
4626 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
4629 mddev->private = NULL;
4634 static void print_sh(struct seq_file *seq, struct stripe_head *sh)
4638 seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n",
4639 (unsigned long long)sh->sector, sh->pd_idx, sh->state);
4640 seq_printf(seq, "sh %llu, count %d.\n",
4641 (unsigned long long)sh->sector, atomic_read(&sh->count));
4642 seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector);
4643 for (i = 0; i < sh->disks; i++) {
4644 seq_printf(seq, "(cache%d: %p %ld) ",
4645 i, sh->dev[i].page, sh->dev[i].flags);
4647 seq_printf(seq, "\n");
4650 static void printall(struct seq_file *seq, raid5_conf_t *conf)
4652 struct stripe_head *sh;
4653 struct hlist_node *hn;
4656 spin_lock_irq(&conf->device_lock);
4657 for (i = 0; i < NR_HASH; i++) {
4658 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
4659 if (sh->raid_conf != conf)
4664 spin_unlock_irq(&conf->device_lock);
4668 static void status(struct seq_file *seq, mddev_t *mddev)
4670 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
4673 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
4674 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
4675 for (i = 0; i < conf->raid_disks; i++)
4676 seq_printf (seq, "%s",
4677 conf->disks[i].rdev &&
4678 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
4679 seq_printf (seq, "]");
4681 seq_printf (seq, "\n");
4682 printall(seq, conf);
4686 static void print_raid5_conf (raid5_conf_t *conf)
4689 struct disk_info *tmp;
4691 printk("RAID5 conf printout:\n");
4693 printk("(conf==NULL)\n");
4696 printk(" --- rd:%d wd:%d\n", conf->raid_disks,
4697 conf->raid_disks - conf->mddev->degraded);
4699 for (i = 0; i < conf->raid_disks; i++) {
4700 char b[BDEVNAME_SIZE];
4701 tmp = conf->disks + i;
4703 printk(" disk %d, o:%d, dev:%s\n",
4704 i, !test_bit(Faulty, &tmp->rdev->flags),
4705 bdevname(tmp->rdev->bdev,b));
4709 static int raid5_spare_active(mddev_t *mddev)
4712 raid5_conf_t *conf = mddev->private;
4713 struct disk_info *tmp;
4715 for (i = 0; i < conf->raid_disks; i++) {
4716 tmp = conf->disks + i;
4718 && !test_bit(Faulty, &tmp->rdev->flags)
4719 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
4720 unsigned long flags;
4721 spin_lock_irqsave(&conf->device_lock, flags);
4723 spin_unlock_irqrestore(&conf->device_lock, flags);
4726 print_raid5_conf(conf);
4730 static int raid5_remove_disk(mddev_t *mddev, int number)
4732 raid5_conf_t *conf = mddev->private;
4735 struct disk_info *p = conf->disks + number;
4737 print_raid5_conf(conf);
4740 if (number >= conf->raid_disks &&
4741 conf->reshape_progress == MaxSector)
4742 clear_bit(In_sync, &rdev->flags);
4744 if (test_bit(In_sync, &rdev->flags) ||
4745 atomic_read(&rdev->nr_pending)) {
4749 /* Only remove non-faulty devices if recovery
4752 if (!test_bit(Faulty, &rdev->flags) &&
4753 mddev->degraded <= conf->max_degraded &&
4754 number < conf->raid_disks) {
4760 if (atomic_read(&rdev->nr_pending)) {
4761 /* lost the race, try later */
4768 print_raid5_conf(conf);
4772 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
4774 raid5_conf_t *conf = mddev->private;
4777 struct disk_info *p;
4779 int last = conf->raid_disks - 1;
4781 if (mddev->degraded > conf->max_degraded)
4782 /* no point adding a device */
4785 if (rdev->raid_disk >= 0)
4786 first = last = rdev->raid_disk;
4789 * find the disk ... but prefer rdev->saved_raid_disk
4792 if (rdev->saved_raid_disk >= 0 &&
4793 rdev->saved_raid_disk >= first &&
4794 conf->disks[rdev->saved_raid_disk].rdev == NULL)
4795 disk = rdev->saved_raid_disk;
4798 for ( ; disk <= last ; disk++)
4799 if ((p=conf->disks + disk)->rdev == NULL) {
4800 clear_bit(In_sync, &rdev->flags);
4801 rdev->raid_disk = disk;
4803 if (rdev->saved_raid_disk != disk)
4805 rcu_assign_pointer(p->rdev, rdev);
4808 print_raid5_conf(conf);
4812 static int raid5_resize(mddev_t *mddev, sector_t sectors)
4814 /* no resync is happening, and there is enough space
4815 * on all devices, so we can resize.
4816 * We need to make sure resync covers any new space.
4817 * If the array is shrinking we should possibly wait until
4818 * any io in the removed space completes, but it hardly seems
4821 sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
4822 md_set_array_sectors(mddev, raid5_size(mddev, sectors,
4823 mddev->raid_disks));
4824 if (mddev->array_sectors >
4825 raid5_size(mddev, sectors, mddev->raid_disks))
4827 set_capacity(mddev->gendisk, mddev->array_sectors);
4829 if (sectors > mddev->dev_sectors && mddev->recovery_cp == MaxSector) {
4830 mddev->recovery_cp = mddev->dev_sectors;
4831 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4833 mddev->dev_sectors = sectors;
4834 mddev->resync_max_sectors = sectors;
4838 static int raid5_check_reshape(mddev_t *mddev)
4840 raid5_conf_t *conf = mddev_to_conf(mddev);
4842 if (mddev->delta_disks == 0 &&
4843 mddev->new_layout == mddev->layout &&
4844 mddev->new_chunk == mddev->chunk_size)
4845 return -EINVAL; /* nothing to do */
4847 /* Cannot grow a bitmap yet */
4849 if (mddev->degraded > conf->max_degraded)
4851 if (mddev->delta_disks < 0) {
4852 /* We might be able to shrink, but the devices must
4853 * be made bigger first.
4854 * For raid6, 4 is the minimum size.
4855 * Otherwise 2 is the minimum
4858 if (mddev->level == 6)
4860 if (mddev->raid_disks + mddev->delta_disks < min)
4864 /* Can only proceed if there are plenty of stripe_heads.
4865 * We need a minimum of one full stripe,, and for sensible progress
4866 * it is best to have about 4 times that.
4867 * If we require 4 times, then the default 256 4K stripe_heads will
4868 * allow for chunk sizes up to 256K, which is probably OK.
4869 * If the chunk size is greater, user-space should request more
4870 * stripe_heads first.
4872 if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes ||
4873 (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
4874 printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n",
4875 (max(mddev->chunk_size, mddev->new_chunk)
4880 return resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
4883 static int raid5_start_reshape(mddev_t *mddev)
4885 raid5_conf_t *conf = mddev_to_conf(mddev);
4888 int added_devices = 0;
4889 unsigned long flags;
4891 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4894 list_for_each_entry(rdev, &mddev->disks, same_set)
4895 if (rdev->raid_disk < 0 &&
4896 !test_bit(Faulty, &rdev->flags))
4899 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
4900 /* Not enough devices even to make a degraded array
4905 /* Refuse to reduce size of the array. Any reductions in
4906 * array size must be through explicit setting of array_size
4909 if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
4910 < mddev->array_sectors) {
4911 printk(KERN_ERR "md: %s: array size must be reduced "
4912 "before number of disks\n", mdname(mddev));
4916 atomic_set(&conf->reshape_stripes, 0);
4917 spin_lock_irq(&conf->device_lock);
4918 conf->previous_raid_disks = conf->raid_disks;
4919 conf->raid_disks += mddev->delta_disks;
4920 conf->prev_chunk = conf->chunk_size;
4921 conf->chunk_size = mddev->new_chunk;
4922 conf->prev_algo = conf->algorithm;
4923 conf->algorithm = mddev->new_layout;
4924 if (mddev->delta_disks < 0)
4925 conf->reshape_progress = raid5_size(mddev, 0, 0);
4927 conf->reshape_progress = 0;
4928 conf->reshape_safe = conf->reshape_progress;
4930 spin_unlock_irq(&conf->device_lock);
4932 /* Add some new drives, as many as will fit.
4933 * We know there are enough to make the newly sized array work.
4935 list_for_each_entry(rdev, &mddev->disks, same_set)
4936 if (rdev->raid_disk < 0 &&
4937 !test_bit(Faulty, &rdev->flags)) {
4938 if (raid5_add_disk(mddev, rdev) == 0) {
4940 set_bit(In_sync, &rdev->flags);
4942 rdev->recovery_offset = 0;
4943 sprintf(nm, "rd%d", rdev->raid_disk);
4944 if (sysfs_create_link(&mddev->kobj,
4947 "raid5: failed to create "
4948 " link %s for %s\n",
4954 if (mddev->delta_disks > 0) {
4955 spin_lock_irqsave(&conf->device_lock, flags);
4956 mddev->degraded = (conf->raid_disks - conf->previous_raid_disks)
4958 spin_unlock_irqrestore(&conf->device_lock, flags);
4960 mddev->raid_disks = conf->raid_disks;
4961 mddev->reshape_position = 0;
4962 set_bit(MD_CHANGE_DEVS, &mddev->flags);
4964 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4965 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4966 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4967 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4968 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4970 if (!mddev->sync_thread) {
4971 mddev->recovery = 0;
4972 spin_lock_irq(&conf->device_lock);
4973 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
4974 conf->reshape_progress = MaxSector;
4975 spin_unlock_irq(&conf->device_lock);
4978 conf->reshape_checkpoint = jiffies;
4979 md_wakeup_thread(mddev->sync_thread);
4980 md_new_event(mddev);
4984 /* This is called from the reshape thread and should make any
4985 * changes needed in 'conf'
4987 static void end_reshape(raid5_conf_t *conf)
4990 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
4992 spin_lock_irq(&conf->device_lock);
4993 conf->previous_raid_disks = conf->raid_disks;
4994 conf->reshape_progress = MaxSector;
4995 spin_unlock_irq(&conf->device_lock);
4996 wake_up(&conf->wait_for_overlap);
4998 /* read-ahead size must cover two whole stripes, which is
4999 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
5002 int data_disks = conf->raid_disks - conf->max_degraded;
5003 int stripe = data_disks * (conf->chunk_size
5005 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
5006 conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
5011 /* This is called from the raid5d thread with mddev_lock held.
5012 * It makes config changes to the device.
5014 static void raid5_finish_reshape(mddev_t *mddev)
5016 struct block_device *bdev;
5017 raid5_conf_t *conf = mddev_to_conf(mddev);
5019 if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
5021 if (mddev->delta_disks > 0) {
5022 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
5023 set_capacity(mddev->gendisk, mddev->array_sectors);
5026 bdev = bdget_disk(mddev->gendisk, 0);
5028 mutex_lock(&bdev->bd_inode->i_mutex);
5029 i_size_write(bdev->bd_inode,
5030 (loff_t)mddev->array_sectors << 9);
5031 mutex_unlock(&bdev->bd_inode->i_mutex);
5036 mddev->degraded = conf->raid_disks;
5037 for (d = 0; d < conf->raid_disks ; d++)
5038 if (conf->disks[d].rdev &&
5040 &conf->disks[d].rdev->flags))
5042 for (d = conf->raid_disks ;
5043 d < conf->raid_disks - mddev->delta_disks;
5045 raid5_remove_disk(mddev, d);
5047 mddev->layout = conf->algorithm;
5048 mddev->chunk_size = conf->chunk_size;
5049 mddev->reshape_position = MaxSector;
5050 mddev->delta_disks = 0;
5054 static void raid5_quiesce(mddev_t *mddev, int state)
5056 raid5_conf_t *conf = mddev_to_conf(mddev);
5059 case 2: /* resume for a suspend */
5060 wake_up(&conf->wait_for_overlap);
5063 case 1: /* stop all writes */
5064 spin_lock_irq(&conf->device_lock);
5066 wait_event_lock_irq(conf->wait_for_stripe,
5067 atomic_read(&conf->active_stripes) == 0 &&
5068 atomic_read(&conf->active_aligned_reads) == 0,
5069 conf->device_lock, /* nothing */);
5070 spin_unlock_irq(&conf->device_lock);
5073 case 0: /* re-enable writes */
5074 spin_lock_irq(&conf->device_lock);
5076 wake_up(&conf->wait_for_stripe);
5077 wake_up(&conf->wait_for_overlap);
5078 spin_unlock_irq(&conf->device_lock);
5084 static void *raid5_takeover_raid1(mddev_t *mddev)
5088 if (mddev->raid_disks != 2 ||
5089 mddev->degraded > 1)
5090 return ERR_PTR(-EINVAL);
5092 /* Should check if there are write-behind devices? */
5094 chunksect = 64*2; /* 64K by default */
5096 /* The array must be an exact multiple of chunksize */
5097 while (chunksect && (mddev->array_sectors & (chunksect-1)))
5100 if ((chunksect<<9) < STRIPE_SIZE)
5101 /* array size does not allow a suitable chunk size */
5102 return ERR_PTR(-EINVAL);
5104 mddev->new_level = 5;
5105 mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
5106 mddev->new_chunk = chunksect << 9;
5108 return setup_conf(mddev);
5111 static void *raid5_takeover_raid6(mddev_t *mddev)
5115 switch (mddev->layout) {
5116 case ALGORITHM_LEFT_ASYMMETRIC_6:
5117 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
5119 case ALGORITHM_RIGHT_ASYMMETRIC_6:
5120 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
5122 case ALGORITHM_LEFT_SYMMETRIC_6:
5123 new_layout = ALGORITHM_LEFT_SYMMETRIC;
5125 case ALGORITHM_RIGHT_SYMMETRIC_6:
5126 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
5128 case ALGORITHM_PARITY_0_6:
5129 new_layout = ALGORITHM_PARITY_0;
5131 case ALGORITHM_PARITY_N:
5132 new_layout = ALGORITHM_PARITY_N;
5135 return ERR_PTR(-EINVAL);
5137 mddev->new_level = 5;
5138 mddev->new_layout = new_layout;
5139 mddev->delta_disks = -1;
5140 mddev->raid_disks -= 1;
5141 return setup_conf(mddev);
5145 static int raid5_reconfig(mddev_t *mddev, int new_layout, int new_chunk)
5147 /* For a 2-drive array, the layout and chunk size can be changed
5148 * immediately as not restriping is needed.
5149 * For larger arrays we record the new value - after validation
5150 * to be used by a reshape pass.
5152 raid5_conf_t *conf = mddev_to_conf(mddev);
5154 if (new_layout >= 0 && !algorithm_valid_raid5(new_layout))
5156 if (new_chunk > 0) {
5157 if (new_chunk & (new_chunk-1))
5158 /* not a power of 2 */
5160 if (new_chunk < PAGE_SIZE)
5162 if (mddev->array_sectors & ((new_chunk>>9)-1))
5163 /* not factor of array size */
5167 /* They look valid */
5169 if (mddev->raid_disks == 2) {
5171 if (new_layout >= 0) {
5172 conf->algorithm = new_layout;
5173 mddev->layout = mddev->new_layout = new_layout;
5175 if (new_chunk > 0) {
5176 conf->chunk_size = new_chunk;
5177 mddev->chunk_size = mddev->new_chunk = new_chunk;
5179 set_bit(MD_CHANGE_DEVS, &mddev->flags);
5180 md_wakeup_thread(mddev->thread);
5182 if (new_layout >= 0)
5183 mddev->new_layout = new_layout;
5185 mddev->new_chunk = new_chunk;
5190 static int raid6_reconfig(mddev_t *mddev, int new_layout, int new_chunk)
5192 if (new_layout >= 0 && !algorithm_valid_raid6(new_layout))
5194 if (new_chunk > 0) {
5195 if (new_chunk & (new_chunk-1))
5196 /* not a power of 2 */
5198 if (new_chunk < PAGE_SIZE)
5200 if (mddev->array_sectors & ((new_chunk>>9)-1))
5201 /* not factor of array size */
5205 /* They look valid */
5207 if (new_layout >= 0)
5208 mddev->new_layout = new_layout;
5210 mddev->new_chunk = new_chunk;
5215 static void *raid5_takeover(mddev_t *mddev)
5217 /* raid5 can take over:
5218 * raid0 - if all devices are the same - make it a raid4 layout
5219 * raid1 - if there are two drives. We need to know the chunk size
5220 * raid4 - trivial - just use a raid4 layout.
5221 * raid6 - Providing it is a *_6 layout
5223 * For now, just do raid1
5226 if (mddev->level == 1)
5227 return raid5_takeover_raid1(mddev);
5228 if (mddev->level == 4) {
5229 mddev->new_layout = ALGORITHM_PARITY_N;
5230 mddev->new_level = 5;
5231 return setup_conf(mddev);
5233 if (mddev->level == 6)
5234 return raid5_takeover_raid6(mddev);
5236 return ERR_PTR(-EINVAL);
5240 static struct mdk_personality raid5_personality;
5242 static void *raid6_takeover(mddev_t *mddev)
5244 /* Currently can only take over a raid5. We map the
5245 * personality to an equivalent raid6 personality
5246 * with the Q block at the end.
5250 if (mddev->pers != &raid5_personality)
5251 return ERR_PTR(-EINVAL);
5252 if (mddev->degraded > 1)
5253 return ERR_PTR(-EINVAL);
5254 if (mddev->raid_disks > 253)
5255 return ERR_PTR(-EINVAL);
5256 if (mddev->raid_disks < 3)
5257 return ERR_PTR(-EINVAL);
5259 switch (mddev->layout) {
5260 case ALGORITHM_LEFT_ASYMMETRIC:
5261 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
5263 case ALGORITHM_RIGHT_ASYMMETRIC:
5264 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
5266 case ALGORITHM_LEFT_SYMMETRIC:
5267 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
5269 case ALGORITHM_RIGHT_SYMMETRIC:
5270 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
5272 case ALGORITHM_PARITY_0:
5273 new_layout = ALGORITHM_PARITY_0_6;
5275 case ALGORITHM_PARITY_N:
5276 new_layout = ALGORITHM_PARITY_N;
5279 return ERR_PTR(-EINVAL);
5281 mddev->new_level = 6;
5282 mddev->new_layout = new_layout;
5283 mddev->delta_disks = 1;
5284 mddev->raid_disks += 1;
5285 return setup_conf(mddev);
5289 static struct mdk_personality raid6_personality =
5293 .owner = THIS_MODULE,
5294 .make_request = make_request,
5298 .error_handler = error,
5299 .hot_add_disk = raid5_add_disk,
5300 .hot_remove_disk= raid5_remove_disk,
5301 .spare_active = raid5_spare_active,
5302 .sync_request = sync_request,
5303 .resize = raid5_resize,
5305 .check_reshape = raid5_check_reshape,
5306 .start_reshape = raid5_start_reshape,
5307 .finish_reshape = raid5_finish_reshape,
5308 .quiesce = raid5_quiesce,
5309 .takeover = raid6_takeover,
5310 .reconfig = raid6_reconfig,
5312 static struct mdk_personality raid5_personality =
5316 .owner = THIS_MODULE,
5317 .make_request = make_request,
5321 .error_handler = error,
5322 .hot_add_disk = raid5_add_disk,
5323 .hot_remove_disk= raid5_remove_disk,
5324 .spare_active = raid5_spare_active,
5325 .sync_request = sync_request,
5326 .resize = raid5_resize,
5328 .check_reshape = raid5_check_reshape,
5329 .start_reshape = raid5_start_reshape,
5330 .finish_reshape = raid5_finish_reshape,
5331 .quiesce = raid5_quiesce,
5332 .takeover = raid5_takeover,
5333 .reconfig = raid5_reconfig,
5336 static struct mdk_personality raid4_personality =
5340 .owner = THIS_MODULE,
5341 .make_request = make_request,
5345 .error_handler = error,
5346 .hot_add_disk = raid5_add_disk,
5347 .hot_remove_disk= raid5_remove_disk,
5348 .spare_active = raid5_spare_active,
5349 .sync_request = sync_request,
5350 .resize = raid5_resize,
5352 .check_reshape = raid5_check_reshape,
5353 .start_reshape = raid5_start_reshape,
5354 .finish_reshape = raid5_finish_reshape,
5355 .quiesce = raid5_quiesce,
5358 static int __init raid5_init(void)
5360 register_md_personality(&raid6_personality);
5361 register_md_personality(&raid5_personality);
5362 register_md_personality(&raid4_personality);
5366 static void raid5_exit(void)
5368 unregister_md_personality(&raid6_personality);
5369 unregister_md_personality(&raid5_personality);
5370 unregister_md_personality(&raid4_personality);
5373 module_init(raid5_init);
5374 module_exit(raid5_exit);
5375 MODULE_LICENSE("GPL");
5376 MODULE_ALIAS("md-personality-4"); /* RAID5 */
5377 MODULE_ALIAS("md-raid5");
5378 MODULE_ALIAS("md-raid4");
5379 MODULE_ALIAS("md-level-5");
5380 MODULE_ALIAS("md-level-4");
5381 MODULE_ALIAS("md-personality-8"); /* RAID6 */
5382 MODULE_ALIAS("md-raid6");
5383 MODULE_ALIAS("md-level-6");
5385 /* This used to be two separate modules, they were: */
5386 MODULE_ALIAS("raid5");
5387 MODULE_ALIAS("raid6");