2 * Copyright (C) 2003 Sistina Software Limited.
4 * This file is released under the GPL.
8 #include "dm-bio-list.h"
13 #include <linux/ctype.h>
14 #include <linux/init.h>
15 #include <linux/mempool.h>
16 #include <linux/module.h>
17 #include <linux/pagemap.h>
18 #include <linux/slab.h>
19 #include <linux/time.h>
20 #include <linux/vmalloc.h>
21 #include <linux/workqueue.h>
23 static struct workqueue_struct *_kmirrord_wq;
24 static struct work_struct _kmirrord_work;
26 static inline void wake(void)
28 queue_work(_kmirrord_wq, &_kmirrord_work);
31 /*-----------------------------------------------------------------
34 * The mirror splits itself up into discrete regions. Each
35 * region can be in one of three states: clean, dirty,
36 * nosync. There is no need to put clean regions in the hash.
38 * In addition to being present in the hash table a region _may_
39 * be present on one of three lists.
41 * clean_regions: Regions on this list have no io pending to
42 * them, they are in sync, we are no longer interested in them,
43 * they are dull. rh_update_states() will remove them from the
46 * quiesced_regions: These regions have been spun down, ready
47 * for recovery. rh_recovery_start() will remove regions from
48 * this list and hand them to kmirrord, which will schedule the
49 * recovery io with kcopyd.
51 * recovered_regions: Regions that kcopyd has successfully
52 * recovered. rh_update_states() will now schedule any delayed
53 * io, up the recovery_count, and remove the region from the
57 * A rw spin lock 'hash_lock' protects just the hash table,
58 * this is never held in write mode from interrupt context,
59 * which I believe means that we only have to disable irqs when
62 * An ordinary spin lock 'region_lock' that protects the three
63 * lists in the region_hash, with the 'state', 'list' and
64 * 'bhs_delayed' fields of the regions. This is used from irq
65 * context, so all other uses will have to suspend local irqs.
66 *---------------------------------------------------------------*/
69 struct mirror_set *ms;
71 unsigned region_shift;
73 /* holds persistent region state */
74 struct dirty_log *log;
78 mempool_t *region_pool;
80 unsigned int nr_buckets;
81 struct list_head *buckets;
83 spinlock_t region_lock;
84 struct semaphore recovery_count;
85 struct list_head clean_regions;
86 struct list_head quiesced_regions;
87 struct list_head recovered_regions;
98 struct region_hash *rh; /* FIXME: can we get rid of this ? */
102 struct list_head hash_list;
103 struct list_head list;
106 struct bio_list delayed_bios;
110 /*-----------------------------------------------------------------
111 * Mirror set structures.
112 *---------------------------------------------------------------*/
114 atomic_t error_count;
120 struct dm_target *ti;
121 struct list_head list;
122 struct region_hash rh;
123 struct kcopyd_client *kcopyd_client;
125 spinlock_t lock; /* protects the next two lists */
126 struct bio_list reads;
127 struct bio_list writes;
133 struct mirror *default_mirror; /* Default mirror */
135 unsigned int nr_mirrors;
136 struct mirror mirror[0];
142 static inline region_t bio_to_region(struct region_hash *rh, struct bio *bio)
144 return (bio->bi_sector - rh->ms->ti->begin) >> rh->region_shift;
147 static inline sector_t region_to_sector(struct region_hash *rh, region_t region)
149 return region << rh->region_shift;
152 /* FIXME move this */
153 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw);
155 #define MIN_REGIONS 64
156 #define MAX_RECOVERY 1
157 static int rh_init(struct region_hash *rh, struct mirror_set *ms,
158 struct dirty_log *log, uint32_t region_size,
161 unsigned int nr_buckets, max_buckets;
165 * Calculate a suitable number of buckets for our hash
168 max_buckets = nr_regions >> 6;
169 for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1)
175 rh->region_size = region_size;
176 rh->region_shift = ffs(region_size) - 1;
177 rwlock_init(&rh->hash_lock);
178 rh->mask = nr_buckets - 1;
179 rh->nr_buckets = nr_buckets;
181 rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets));
183 DMERR("unable to allocate region hash memory");
187 for (i = 0; i < nr_buckets; i++)
188 INIT_LIST_HEAD(rh->buckets + i);
190 spin_lock_init(&rh->region_lock);
191 sema_init(&rh->recovery_count, 0);
192 INIT_LIST_HEAD(&rh->clean_regions);
193 INIT_LIST_HEAD(&rh->quiesced_regions);
194 INIT_LIST_HEAD(&rh->recovered_regions);
196 rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS,
197 sizeof(struct region));
198 if (!rh->region_pool) {
207 static void rh_exit(struct region_hash *rh)
210 struct region *reg, *nreg;
212 BUG_ON(!list_empty(&rh->quiesced_regions));
213 for (h = 0; h < rh->nr_buckets; h++) {
214 list_for_each_entry_safe(reg, nreg, rh->buckets + h, hash_list) {
215 BUG_ON(atomic_read(®->pending));
216 mempool_free(reg, rh->region_pool);
221 dm_destroy_dirty_log(rh->log);
223 mempool_destroy(rh->region_pool);
227 #define RH_HASH_MULT 2654435387U
229 static inline unsigned int rh_hash(struct region_hash *rh, region_t region)
231 return (unsigned int) ((region * RH_HASH_MULT) >> 12) & rh->mask;
234 static struct region *__rh_lookup(struct region_hash *rh, region_t region)
238 list_for_each_entry (reg, rh->buckets + rh_hash(rh, region), hash_list)
239 if (reg->key == region)
245 static void __rh_insert(struct region_hash *rh, struct region *reg)
247 unsigned int h = rh_hash(rh, reg->key);
248 list_add(®->hash_list, rh->buckets + h);
251 static struct region *__rh_alloc(struct region_hash *rh, region_t region)
253 struct region *reg, *nreg;
255 read_unlock(&rh->hash_lock);
256 nreg = mempool_alloc(rh->region_pool, GFP_ATOMIC);
258 nreg = kmalloc(sizeof(struct region), GFP_NOIO);
259 nreg->state = rh->log->type->in_sync(rh->log, region, 1) ?
260 RH_CLEAN : RH_NOSYNC;
264 INIT_LIST_HEAD(&nreg->list);
266 atomic_set(&nreg->pending, 0);
267 bio_list_init(&nreg->delayed_bios);
268 write_lock_irq(&rh->hash_lock);
270 reg = __rh_lookup(rh, region);
272 /* we lost the race */
273 mempool_free(nreg, rh->region_pool);
276 __rh_insert(rh, nreg);
277 if (nreg->state == RH_CLEAN) {
278 spin_lock(&rh->region_lock);
279 list_add(&nreg->list, &rh->clean_regions);
280 spin_unlock(&rh->region_lock);
284 write_unlock_irq(&rh->hash_lock);
285 read_lock(&rh->hash_lock);
290 static inline struct region *__rh_find(struct region_hash *rh, region_t region)
294 reg = __rh_lookup(rh, region);
296 reg = __rh_alloc(rh, region);
301 static int rh_state(struct region_hash *rh, region_t region, int may_block)
306 read_lock(&rh->hash_lock);
307 reg = __rh_lookup(rh, region);
308 read_unlock(&rh->hash_lock);
314 * The region wasn't in the hash, so we fall back to the
317 r = rh->log->type->in_sync(rh->log, region, may_block);
320 * Any error from the dirty log (eg. -EWOULDBLOCK) gets
321 * taken as a RH_NOSYNC
323 return r == 1 ? RH_CLEAN : RH_NOSYNC;
326 static inline int rh_in_sync(struct region_hash *rh,
327 region_t region, int may_block)
329 int state = rh_state(rh, region, may_block);
330 return state == RH_CLEAN || state == RH_DIRTY;
333 static void dispatch_bios(struct mirror_set *ms, struct bio_list *bio_list)
337 while ((bio = bio_list_pop(bio_list))) {
338 queue_bio(ms, bio, WRITE);
342 static void rh_update_states(struct region_hash *rh)
344 struct region *reg, *next;
347 LIST_HEAD(recovered);
350 * Quickly grab the lists.
352 write_lock_irq(&rh->hash_lock);
353 spin_lock(&rh->region_lock);
354 if (!list_empty(&rh->clean_regions)) {
355 list_splice(&rh->clean_regions, &clean);
356 INIT_LIST_HEAD(&rh->clean_regions);
358 list_for_each_entry (reg, &clean, list) {
359 rh->log->type->clear_region(rh->log, reg->key);
360 list_del(®->hash_list);
364 if (!list_empty(&rh->recovered_regions)) {
365 list_splice(&rh->recovered_regions, &recovered);
366 INIT_LIST_HEAD(&rh->recovered_regions);
368 list_for_each_entry (reg, &recovered, list)
369 list_del(®->hash_list);
371 spin_unlock(&rh->region_lock);
372 write_unlock_irq(&rh->hash_lock);
375 * All the regions on the recovered and clean lists have
376 * now been pulled out of the system, so no need to do
379 list_for_each_entry_safe (reg, next, &recovered, list) {
380 rh->log->type->clear_region(rh->log, reg->key);
381 rh->log->type->complete_resync_work(rh->log, reg->key, 1);
382 dispatch_bios(rh->ms, ®->delayed_bios);
383 up(&rh->recovery_count);
384 mempool_free(reg, rh->region_pool);
387 if (!list_empty(&recovered))
388 rh->log->type->flush(rh->log);
390 list_for_each_entry_safe (reg, next, &clean, list)
391 mempool_free(reg, rh->region_pool);
394 static void rh_inc(struct region_hash *rh, region_t region)
398 read_lock(&rh->hash_lock);
399 reg = __rh_find(rh, region);
401 spin_lock_irq(&rh->region_lock);
402 atomic_inc(®->pending);
404 if (reg->state == RH_CLEAN) {
405 reg->state = RH_DIRTY;
406 list_del_init(®->list); /* take off the clean list */
407 spin_unlock_irq(&rh->region_lock);
409 rh->log->type->mark_region(rh->log, reg->key);
411 spin_unlock_irq(&rh->region_lock);
414 read_unlock(&rh->hash_lock);
417 static void rh_inc_pending(struct region_hash *rh, struct bio_list *bios)
421 for (bio = bios->head; bio; bio = bio->bi_next)
422 rh_inc(rh, bio_to_region(rh, bio));
425 static void rh_dec(struct region_hash *rh, region_t region)
431 read_lock(&rh->hash_lock);
432 reg = __rh_lookup(rh, region);
433 read_unlock(&rh->hash_lock);
435 spin_lock_irqsave(&rh->region_lock, flags);
436 if (atomic_dec_and_test(®->pending)) {
438 * There is no pending I/O for this region.
439 * We can move the region to corresponding list for next action.
440 * At this point, the region is not yet connected to any list.
442 * If the state is RH_NOSYNC, the region should be kept off
444 * The hash entry for RH_NOSYNC will remain in memory
445 * until the region is recovered or the map is reloaded.
448 /* do nothing for RH_NOSYNC */
449 if (reg->state == RH_RECOVERING) {
450 list_add_tail(®->list, &rh->quiesced_regions);
451 } else if (reg->state == RH_DIRTY) {
452 reg->state = RH_CLEAN;
453 list_add(®->list, &rh->clean_regions);
457 spin_unlock_irqrestore(&rh->region_lock, flags);
464 * Starts quiescing a region in preparation for recovery.
466 static int __rh_recovery_prepare(struct region_hash *rh)
473 * Ask the dirty log what's next.
475 r = rh->log->type->get_resync_work(rh->log, ®ion);
480 * Get this region, and start it quiescing by setting the
483 read_lock(&rh->hash_lock);
484 reg = __rh_find(rh, region);
485 read_unlock(&rh->hash_lock);
487 spin_lock_irq(&rh->region_lock);
488 reg->state = RH_RECOVERING;
490 /* Already quiesced ? */
491 if (atomic_read(®->pending))
492 list_del_init(®->list);
495 list_del_init(®->list);
496 list_add(®->list, &rh->quiesced_regions);
498 spin_unlock_irq(&rh->region_lock);
503 static void rh_recovery_prepare(struct region_hash *rh)
505 while (!down_trylock(&rh->recovery_count))
506 if (__rh_recovery_prepare(rh) <= 0) {
507 up(&rh->recovery_count);
513 * Returns any quiesced regions.
515 static struct region *rh_recovery_start(struct region_hash *rh)
517 struct region *reg = NULL;
519 spin_lock_irq(&rh->region_lock);
520 if (!list_empty(&rh->quiesced_regions)) {
521 reg = list_entry(rh->quiesced_regions.next,
522 struct region, list);
523 list_del_init(®->list); /* remove from the quiesced list */
525 spin_unlock_irq(&rh->region_lock);
530 /* FIXME: success ignored for now */
531 static void rh_recovery_end(struct region *reg, int success)
533 struct region_hash *rh = reg->rh;
535 spin_lock_irq(&rh->region_lock);
536 list_add(®->list, ®->rh->recovered_regions);
537 spin_unlock_irq(&rh->region_lock);
542 static void rh_flush(struct region_hash *rh)
544 rh->log->type->flush(rh->log);
547 static void rh_delay(struct region_hash *rh, struct bio *bio)
551 read_lock(&rh->hash_lock);
552 reg = __rh_find(rh, bio_to_region(rh, bio));
553 bio_list_add(®->delayed_bios, bio);
554 read_unlock(&rh->hash_lock);
557 static void rh_stop_recovery(struct region_hash *rh)
561 /* wait for any recovering regions */
562 for (i = 0; i < MAX_RECOVERY; i++)
563 down(&rh->recovery_count);
566 static void rh_start_recovery(struct region_hash *rh)
570 for (i = 0; i < MAX_RECOVERY; i++)
571 up(&rh->recovery_count);
577 * Every mirror should look like this one.
579 #define DEFAULT_MIRROR 0
582 * This is yucky. We squirrel the mirror_set struct away inside
583 * bi_next for write buffers. This is safe since the bh
584 * doesn't get submitted to the lower levels of block layer.
586 static struct mirror_set *bio_get_ms(struct bio *bio)
588 return (struct mirror_set *) bio->bi_next;
591 static void bio_set_ms(struct bio *bio, struct mirror_set *ms)
593 bio->bi_next = (struct bio *) ms;
596 /*-----------------------------------------------------------------
599 * When a mirror is first activated we may find that some regions
600 * are in the no-sync state. We have to recover these by
601 * recopying from the default mirror to all the others.
602 *---------------------------------------------------------------*/
603 static void recovery_complete(int read_err, unsigned int write_err,
606 struct region *reg = (struct region *) context;
608 /* FIXME: better error handling */
609 rh_recovery_end(reg, read_err || write_err);
612 static int recover(struct mirror_set *ms, struct region *reg)
616 struct io_region from, to[KCOPYD_MAX_REGIONS], *dest;
618 unsigned long flags = 0;
620 /* fill in the source */
621 m = ms->default_mirror;
622 from.bdev = m->dev->bdev;
623 from.sector = m->offset + region_to_sector(reg->rh, reg->key);
624 if (reg->key == (ms->nr_regions - 1)) {
626 * The final region may be smaller than
629 from.count = ms->ti->len & (reg->rh->region_size - 1);
631 from.count = reg->rh->region_size;
633 from.count = reg->rh->region_size;
635 /* fill in the destinations */
636 for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
637 if (&ms->mirror[i] == ms->default_mirror)
641 dest->bdev = m->dev->bdev;
642 dest->sector = m->offset + region_to_sector(reg->rh, reg->key);
643 dest->count = from.count;
648 set_bit(KCOPYD_IGNORE_ERROR, &flags);
649 r = kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, flags,
650 recovery_complete, reg);
655 static void do_recovery(struct mirror_set *ms)
659 struct dirty_log *log = ms->rh.log;
662 * Start quiescing some regions.
664 rh_recovery_prepare(&ms->rh);
667 * Copy any already quiesced regions.
669 while ((reg = rh_recovery_start(&ms->rh))) {
670 r = recover(ms, reg);
672 rh_recovery_end(reg, 0);
676 * Update the in sync flag.
679 (log->type->get_sync_count(log) == ms->nr_regions)) {
680 /* the sync is complete */
681 dm_table_event(ms->ti->table);
686 /*-----------------------------------------------------------------
688 *---------------------------------------------------------------*/
689 static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
691 /* FIXME: add read balancing */
692 return ms->default_mirror;
696 * remap a buffer to a particular mirror.
698 static void map_bio(struct mirror_set *ms, struct mirror *m, struct bio *bio)
700 bio->bi_bdev = m->dev->bdev;
701 bio->bi_sector = m->offset + (bio->bi_sector - ms->ti->begin);
704 static void do_reads(struct mirror_set *ms, struct bio_list *reads)
710 while ((bio = bio_list_pop(reads))) {
711 region = bio_to_region(&ms->rh, bio);
714 * We can only read balance if the region is in sync.
716 if (rh_in_sync(&ms->rh, region, 0))
717 m = choose_mirror(ms, bio->bi_sector);
719 m = ms->default_mirror;
722 generic_make_request(bio);
726 /*-----------------------------------------------------------------
729 * We do different things with the write io depending on the
730 * state of the region that it's in:
732 * SYNC: increment pending, use kcopyd to write to *all* mirrors
733 * RECOVERING: delay the io until recovery completes
734 * NOSYNC: increment pending, just write to the default mirror
735 *---------------------------------------------------------------*/
736 static void write_callback(unsigned long error, void *context)
740 struct bio *bio = (struct bio *) context;
741 struct mirror_set *ms;
743 ms = bio_get_ms(bio);
744 bio_set_ms(bio, NULL);
747 * NOTE: We don't decrement the pending count here,
748 * instead it is done by the targets endio function.
749 * This way we handle both writes to SYNC and NOSYNC
750 * regions with the same code.
755 * only error the io if all mirrors failed.
759 for (i = 0; i < ms->nr_mirrors; i++)
760 if (!test_bit(i, &error)) {
765 bio_endio(bio, bio->bi_size, 0);
768 static void do_write(struct mirror_set *ms, struct bio *bio)
771 struct io_region io[KCOPYD_MAX_REGIONS+1];
774 for (i = 0; i < ms->nr_mirrors; i++) {
777 io[i].bdev = m->dev->bdev;
778 io[i].sector = m->offset + (bio->bi_sector - ms->ti->begin);
779 io[i].count = bio->bi_size >> 9;
783 dm_io_async_bvec(ms->nr_mirrors, io, WRITE,
784 bio->bi_io_vec + bio->bi_idx,
785 write_callback, bio);
788 static void do_writes(struct mirror_set *ms, struct bio_list *writes)
792 struct bio_list sync, nosync, recover, *this_list = NULL;
798 * Classify each write.
800 bio_list_init(&sync);
801 bio_list_init(&nosync);
802 bio_list_init(&recover);
804 while ((bio = bio_list_pop(writes))) {
805 state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1);
817 this_list = &recover;
821 bio_list_add(this_list, bio);
825 * Increment the pending counts for any regions that will
826 * be written to (writes to recover regions are going to
829 rh_inc_pending(&ms->rh, &sync);
830 rh_inc_pending(&ms->rh, &nosync);
836 while ((bio = bio_list_pop(&sync)))
839 while ((bio = bio_list_pop(&recover)))
840 rh_delay(&ms->rh, bio);
842 while ((bio = bio_list_pop(&nosync))) {
843 map_bio(ms, ms->default_mirror, bio);
844 generic_make_request(bio);
848 /*-----------------------------------------------------------------
850 *---------------------------------------------------------------*/
851 static LIST_HEAD(_mirror_sets);
852 static DECLARE_RWSEM(_mirror_sets_lock);
854 static void do_mirror(struct mirror_set *ms)
856 struct bio_list reads, writes;
858 spin_lock(&ms->lock);
861 bio_list_init(&ms->reads);
862 bio_list_init(&ms->writes);
863 spin_unlock(&ms->lock);
865 rh_update_states(&ms->rh);
867 do_reads(ms, &reads);
868 do_writes(ms, &writes);
871 static void do_work(void *ignored)
873 struct mirror_set *ms;
875 down_read(&_mirror_sets_lock);
876 list_for_each_entry (ms, &_mirror_sets, list)
878 up_read(&_mirror_sets_lock);
881 /*-----------------------------------------------------------------
883 *---------------------------------------------------------------*/
884 static struct mirror_set *alloc_context(unsigned int nr_mirrors,
885 uint32_t region_size,
886 struct dm_target *ti,
887 struct dirty_log *dl)
890 struct mirror_set *ms = NULL;
892 if (array_too_big(sizeof(*ms), sizeof(ms->mirror[0]), nr_mirrors))
895 len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors);
897 ms = kmalloc(len, GFP_KERNEL);
899 ti->error = "dm-mirror: Cannot allocate mirror context";
904 spin_lock_init(&ms->lock);
907 ms->nr_mirrors = nr_mirrors;
908 ms->nr_regions = dm_sector_div_up(ti->len, region_size);
910 ms->default_mirror = &ms->mirror[DEFAULT_MIRROR];
912 if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) {
913 ti->error = "dm-mirror: Error creating dirty region hash";
921 static void free_context(struct mirror_set *ms, struct dm_target *ti,
925 dm_put_device(ti, ms->mirror[m].dev);
931 static inline int _check_region_size(struct dm_target *ti, uint32_t size)
933 return !(size % (PAGE_SIZE >> 9) || (size & (size - 1)) ||
937 static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
938 unsigned int mirror, char **argv)
940 unsigned long long offset;
942 if (sscanf(argv[1], "%llu", &offset) != 1) {
943 ti->error = "dm-mirror: Invalid offset";
947 if (dm_get_device(ti, argv[0], offset, ti->len,
948 dm_table_get_mode(ti->table),
949 &ms->mirror[mirror].dev)) {
950 ti->error = "dm-mirror: Device lookup failure";
954 ms->mirror[mirror].offset = offset;
959 static int add_mirror_set(struct mirror_set *ms)
961 down_write(&_mirror_sets_lock);
962 list_add_tail(&ms->list, &_mirror_sets);
963 up_write(&_mirror_sets_lock);
969 static void del_mirror_set(struct mirror_set *ms)
971 down_write(&_mirror_sets_lock);
973 up_write(&_mirror_sets_lock);
977 * Create dirty log: log_type #log_params <log_params>
979 static struct dirty_log *create_dirty_log(struct dm_target *ti,
980 unsigned int argc, char **argv,
981 unsigned int *args_used)
983 unsigned int param_count;
984 struct dirty_log *dl;
987 ti->error = "dm-mirror: Insufficient mirror log arguments";
991 if (sscanf(argv[1], "%u", ¶m_count) != 1) {
992 ti->error = "dm-mirror: Invalid mirror log argument count";
996 *args_used = 2 + param_count;
998 if (argc < *args_used) {
999 ti->error = "dm-mirror: Insufficient mirror log arguments";
1003 dl = dm_create_dirty_log(argv[0], ti, param_count, argv + 2);
1005 ti->error = "dm-mirror: Error creating mirror dirty log";
1009 if (!_check_region_size(ti, dl->type->get_region_size(dl))) {
1010 ti->error = "dm-mirror: Invalid region size";
1011 dm_destroy_dirty_log(dl);
1019 * Construct a mirror mapping:
1021 * log_type #log_params <log_params>
1022 * #mirrors [mirror_path offset]{2,}
1024 * log_type is "core" or "disk"
1025 * #log_params is between 1 and 3
1027 #define DM_IO_PAGES 64
1028 static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1031 unsigned int nr_mirrors, m, args_used;
1032 struct mirror_set *ms;
1033 struct dirty_log *dl;
1035 dl = create_dirty_log(ti, argc, argv, &args_used);
1042 if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 ||
1043 nr_mirrors < 2 || nr_mirrors > KCOPYD_MAX_REGIONS + 1) {
1044 ti->error = "dm-mirror: Invalid number of mirrors";
1045 dm_destroy_dirty_log(dl);
1051 if (argc != nr_mirrors * 2) {
1052 ti->error = "dm-mirror: Wrong number of mirror arguments";
1053 dm_destroy_dirty_log(dl);
1057 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
1059 dm_destroy_dirty_log(dl);
1063 /* Get the mirror parameter sets */
1064 for (m = 0; m < nr_mirrors; m++) {
1065 r = get_mirror(ms, ti, m, argv);
1067 free_context(ms, ti, m);
1075 ti->split_io = ms->rh.region_size;
1077 r = kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client);
1079 free_context(ms, ti, ms->nr_mirrors);
1087 static void mirror_dtr(struct dm_target *ti)
1089 struct mirror_set *ms = (struct mirror_set *) ti->private;
1092 kcopyd_client_destroy(ms->kcopyd_client);
1093 free_context(ms, ti, ms->nr_mirrors);
1096 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
1098 int should_wake = 0;
1099 struct bio_list *bl;
1101 bl = (rw == WRITE) ? &ms->writes : &ms->reads;
1102 spin_lock(&ms->lock);
1103 should_wake = !(bl->head);
1104 bio_list_add(bl, bio);
1105 spin_unlock(&ms->lock);
1112 * Mirror mapping function
1114 static int mirror_map(struct dm_target *ti, struct bio *bio,
1115 union map_info *map_context)
1117 int r, rw = bio_rw(bio);
1119 struct mirror_set *ms = ti->private;
1121 map_context->ll = bio_to_region(&ms->rh, bio);
1124 queue_bio(ms, bio, rw);
1128 r = ms->rh.log->type->in_sync(ms->rh.log,
1129 bio_to_region(&ms->rh, bio), 0);
1130 if (r < 0 && r != -EWOULDBLOCK)
1133 if (r == -EWOULDBLOCK) /* FIXME: ugly */
1137 * We don't want to fast track a recovery just for a read
1138 * ahead. So we just let it silently fail.
1139 * FIXME: get rid of this.
1141 if (!r && rw == READA)
1145 /* Pass this io over to the daemon */
1146 queue_bio(ms, bio, rw);
1150 m = choose_mirror(ms, bio->bi_sector);
1154 map_bio(ms, m, bio);
1158 static int mirror_end_io(struct dm_target *ti, struct bio *bio,
1159 int error, union map_info *map_context)
1161 int rw = bio_rw(bio);
1162 struct mirror_set *ms = (struct mirror_set *) ti->private;
1163 region_t region = map_context->ll;
1166 * We need to dec pending if this was a write.
1169 rh_dec(&ms->rh, region);
1174 static void mirror_postsuspend(struct dm_target *ti)
1176 struct mirror_set *ms = (struct mirror_set *) ti->private;
1177 struct dirty_log *log = ms->rh.log;
1179 rh_stop_recovery(&ms->rh);
1180 if (log->type->suspend && log->type->suspend(log))
1181 /* FIXME: need better error handling */
1182 DMWARN("log suspend failed");
1185 static void mirror_resume(struct dm_target *ti)
1187 struct mirror_set *ms = (struct mirror_set *) ti->private;
1188 struct dirty_log *log = ms->rh.log;
1189 if (log->type->resume && log->type->resume(log))
1190 /* FIXME: need better error handling */
1191 DMWARN("log resume failed");
1192 rh_start_recovery(&ms->rh);
1195 static int mirror_status(struct dm_target *ti, status_type_t type,
1196 char *result, unsigned int maxlen)
1199 struct mirror_set *ms = (struct mirror_set *) ti->private;
1201 sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen);
1204 case STATUSTYPE_INFO:
1205 DMEMIT("%d ", ms->nr_mirrors);
1206 for (m = 0; m < ms->nr_mirrors; m++)
1207 DMEMIT("%s ", ms->mirror[m].dev->name);
1210 (unsigned long long)ms->rh.log->type->
1211 get_sync_count(ms->rh.log),
1212 (unsigned long long)ms->nr_regions);
1215 case STATUSTYPE_TABLE:
1216 DMEMIT("%d ", ms->nr_mirrors);
1217 for (m = 0; m < ms->nr_mirrors; m++)
1218 DMEMIT("%s %llu ", ms->mirror[m].dev->name,
1219 (unsigned long long)ms->mirror[m].offset);
1225 static struct target_type mirror_target = {
1227 .version = {1, 0, 1},
1228 .module = THIS_MODULE,
1232 .end_io = mirror_end_io,
1233 .postsuspend = mirror_postsuspend,
1234 .resume = mirror_resume,
1235 .status = mirror_status,
1238 static int __init dm_mirror_init(void)
1242 r = dm_dirty_log_init();
1246 _kmirrord_wq = create_singlethread_workqueue("kmirrord");
1247 if (!_kmirrord_wq) {
1248 DMERR("couldn't start kmirrord");
1249 dm_dirty_log_exit();
1252 INIT_WORK(&_kmirrord_work, do_work, NULL);
1254 r = dm_register_target(&mirror_target);
1256 DMERR("%s: Failed to register mirror target",
1257 mirror_target.name);
1258 dm_dirty_log_exit();
1259 destroy_workqueue(_kmirrord_wq);
1265 static void __exit dm_mirror_exit(void)
1269 r = dm_unregister_target(&mirror_target);
1271 DMERR("%s: unregister failed %d", mirror_target.name, r);
1273 destroy_workqueue(_kmirrord_wq);
1274 dm_dirty_log_exit();
1278 module_init(dm_mirror_init);
1279 module_exit(dm_mirror_exit);
1281 MODULE_DESCRIPTION(DM_NAME " mirror target");
1282 MODULE_AUTHOR("Joe Thornber");
1283 MODULE_LICENSE("GPL");