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
;
112 static inline region_t
bio_to_region(struct region_hash
*rh
, struct bio
*bio
)
114 return bio
->bi_sector
>> rh
->region_shift
;
117 static inline sector_t
region_to_sector(struct region_hash
*rh
, region_t region
)
119 return region
<< rh
->region_shift
;
122 /* FIXME move this */
123 static void queue_bio(struct mirror_set
*ms
, struct bio
*bio
, int rw
);
125 #define MIN_REGIONS 64
126 #define MAX_RECOVERY 1
127 static int rh_init(struct region_hash
*rh
, struct mirror_set
*ms
,
128 struct dirty_log
*log
, uint32_t region_size
,
131 unsigned int nr_buckets
, max_buckets
;
135 * Calculate a suitable number of buckets for our hash
138 max_buckets
= nr_regions
>> 6;
139 for (nr_buckets
= 128u; nr_buckets
< max_buckets
; nr_buckets
<<= 1)
145 rh
->region_size
= region_size
;
146 rh
->region_shift
= ffs(region_size
) - 1;
147 rwlock_init(&rh
->hash_lock
);
148 rh
->mask
= nr_buckets
- 1;
149 rh
->nr_buckets
= nr_buckets
;
151 rh
->buckets
= vmalloc(nr_buckets
* sizeof(*rh
->buckets
));
153 DMERR("unable to allocate region hash memory");
157 for (i
= 0; i
< nr_buckets
; i
++)
158 INIT_LIST_HEAD(rh
->buckets
+ i
);
160 spin_lock_init(&rh
->region_lock
);
161 sema_init(&rh
->recovery_count
, 0);
162 INIT_LIST_HEAD(&rh
->clean_regions
);
163 INIT_LIST_HEAD(&rh
->quiesced_regions
);
164 INIT_LIST_HEAD(&rh
->recovered_regions
);
166 rh
->region_pool
= mempool_create_kmalloc_pool(MIN_REGIONS
,
167 sizeof(struct region
));
168 if (!rh
->region_pool
) {
177 static void rh_exit(struct region_hash
*rh
)
180 struct region
*reg
, *nreg
;
182 BUG_ON(!list_empty(&rh
->quiesced_regions
));
183 for (h
= 0; h
< rh
->nr_buckets
; h
++) {
184 list_for_each_entry_safe(reg
, nreg
, rh
->buckets
+ h
, hash_list
) {
185 BUG_ON(atomic_read(®
->pending
));
186 mempool_free(reg
, rh
->region_pool
);
191 dm_destroy_dirty_log(rh
->log
);
193 mempool_destroy(rh
->region_pool
);
197 #define RH_HASH_MULT 2654435387U
199 static inline unsigned int rh_hash(struct region_hash
*rh
, region_t region
)
201 return (unsigned int) ((region
* RH_HASH_MULT
) >> 12) & rh
->mask
;
204 static struct region
*__rh_lookup(struct region_hash
*rh
, region_t region
)
208 list_for_each_entry (reg
, rh
->buckets
+ rh_hash(rh
, region
), hash_list
)
209 if (reg
->key
== region
)
215 static void __rh_insert(struct region_hash
*rh
, struct region
*reg
)
217 unsigned int h
= rh_hash(rh
, reg
->key
);
218 list_add(®
->hash_list
, rh
->buckets
+ h
);
221 static struct region
*__rh_alloc(struct region_hash
*rh
, region_t region
)
223 struct region
*reg
, *nreg
;
225 read_unlock(&rh
->hash_lock
);
226 nreg
= mempool_alloc(rh
->region_pool
, GFP_NOIO
);
227 nreg
->state
= rh
->log
->type
->in_sync(rh
->log
, region
, 1) ?
228 RH_CLEAN
: RH_NOSYNC
;
232 INIT_LIST_HEAD(&nreg
->list
);
234 atomic_set(&nreg
->pending
, 0);
235 bio_list_init(&nreg
->delayed_bios
);
236 write_lock_irq(&rh
->hash_lock
);
238 reg
= __rh_lookup(rh
, region
);
240 /* we lost the race */
241 mempool_free(nreg
, rh
->region_pool
);
244 __rh_insert(rh
, nreg
);
245 if (nreg
->state
== RH_CLEAN
) {
246 spin_lock(&rh
->region_lock
);
247 list_add(&nreg
->list
, &rh
->clean_regions
);
248 spin_unlock(&rh
->region_lock
);
252 write_unlock_irq(&rh
->hash_lock
);
253 read_lock(&rh
->hash_lock
);
258 static inline struct region
*__rh_find(struct region_hash
*rh
, region_t region
)
262 reg
= __rh_lookup(rh
, region
);
264 reg
= __rh_alloc(rh
, region
);
269 static int rh_state(struct region_hash
*rh
, region_t region
, int may_block
)
274 read_lock(&rh
->hash_lock
);
275 reg
= __rh_lookup(rh
, region
);
276 read_unlock(&rh
->hash_lock
);
282 * The region wasn't in the hash, so we fall back to the
285 r
= rh
->log
->type
->in_sync(rh
->log
, region
, may_block
);
288 * Any error from the dirty log (eg. -EWOULDBLOCK) gets
289 * taken as a RH_NOSYNC
291 return r
== 1 ? RH_CLEAN
: RH_NOSYNC
;
294 static inline int rh_in_sync(struct region_hash
*rh
,
295 region_t region
, int may_block
)
297 int state
= rh_state(rh
, region
, may_block
);
298 return state
== RH_CLEAN
|| state
== RH_DIRTY
;
301 static void dispatch_bios(struct mirror_set
*ms
, struct bio_list
*bio_list
)
305 while ((bio
= bio_list_pop(bio_list
))) {
306 queue_bio(ms
, bio
, WRITE
);
310 static void rh_update_states(struct region_hash
*rh
)
312 struct region
*reg
, *next
;
315 LIST_HEAD(recovered
);
318 * Quickly grab the lists.
320 write_lock_irq(&rh
->hash_lock
);
321 spin_lock(&rh
->region_lock
);
322 if (!list_empty(&rh
->clean_regions
)) {
323 list_splice(&rh
->clean_regions
, &clean
);
324 INIT_LIST_HEAD(&rh
->clean_regions
);
326 list_for_each_entry (reg
, &clean
, list
) {
327 rh
->log
->type
->clear_region(rh
->log
, reg
->key
);
328 list_del(®
->hash_list
);
332 if (!list_empty(&rh
->recovered_regions
)) {
333 list_splice(&rh
->recovered_regions
, &recovered
);
334 INIT_LIST_HEAD(&rh
->recovered_regions
);
336 list_for_each_entry (reg
, &recovered
, list
)
337 list_del(®
->hash_list
);
339 spin_unlock(&rh
->region_lock
);
340 write_unlock_irq(&rh
->hash_lock
);
343 * All the regions on the recovered and clean lists have
344 * now been pulled out of the system, so no need to do
347 list_for_each_entry_safe (reg
, next
, &recovered
, list
) {
348 rh
->log
->type
->clear_region(rh
->log
, reg
->key
);
349 rh
->log
->type
->complete_resync_work(rh
->log
, reg
->key
, 1);
350 dispatch_bios(rh
->ms
, ®
->delayed_bios
);
351 up(&rh
->recovery_count
);
352 mempool_free(reg
, rh
->region_pool
);
355 if (!list_empty(&recovered
))
356 rh
->log
->type
->flush(rh
->log
);
358 list_for_each_entry_safe (reg
, next
, &clean
, list
)
359 mempool_free(reg
, rh
->region_pool
);
362 static void rh_inc(struct region_hash
*rh
, region_t region
)
366 read_lock(&rh
->hash_lock
);
367 reg
= __rh_find(rh
, region
);
369 spin_lock_irq(&rh
->region_lock
);
370 atomic_inc(®
->pending
);
372 if (reg
->state
== RH_CLEAN
) {
373 reg
->state
= RH_DIRTY
;
374 list_del_init(®
->list
); /* take off the clean list */
375 spin_unlock_irq(&rh
->region_lock
);
377 rh
->log
->type
->mark_region(rh
->log
, reg
->key
);
379 spin_unlock_irq(&rh
->region_lock
);
382 read_unlock(&rh
->hash_lock
);
385 static void rh_inc_pending(struct region_hash
*rh
, struct bio_list
*bios
)
389 for (bio
= bios
->head
; bio
; bio
= bio
->bi_next
)
390 rh_inc(rh
, bio_to_region(rh
, bio
));
393 static void rh_dec(struct region_hash
*rh
, region_t region
)
399 read_lock(&rh
->hash_lock
);
400 reg
= __rh_lookup(rh
, region
);
401 read_unlock(&rh
->hash_lock
);
403 spin_lock_irqsave(&rh
->region_lock
, flags
);
404 if (atomic_dec_and_test(®
->pending
)) {
405 if (reg
->state
== RH_RECOVERING
) {
406 list_add_tail(®
->list
, &rh
->quiesced_regions
);
408 reg
->state
= RH_CLEAN
;
409 list_add(®
->list
, &rh
->clean_regions
);
413 spin_unlock_irqrestore(&rh
->region_lock
, flags
);
420 * Starts quiescing a region in preparation for recovery.
422 static int __rh_recovery_prepare(struct region_hash
*rh
)
429 * Ask the dirty log what's next.
431 r
= rh
->log
->type
->get_resync_work(rh
->log
, ®ion
);
436 * Get this region, and start it quiescing by setting the
439 read_lock(&rh
->hash_lock
);
440 reg
= __rh_find(rh
, region
);
441 read_unlock(&rh
->hash_lock
);
443 spin_lock_irq(&rh
->region_lock
);
444 reg
->state
= RH_RECOVERING
;
446 /* Already quiesced ? */
447 if (atomic_read(®
->pending
))
448 list_del_init(®
->list
);
451 list_del_init(®
->list
);
452 list_add(®
->list
, &rh
->quiesced_regions
);
454 spin_unlock_irq(&rh
->region_lock
);
459 static void rh_recovery_prepare(struct region_hash
*rh
)
461 while (!down_trylock(&rh
->recovery_count
))
462 if (__rh_recovery_prepare(rh
) <= 0) {
463 up(&rh
->recovery_count
);
469 * Returns any quiesced regions.
471 static struct region
*rh_recovery_start(struct region_hash
*rh
)
473 struct region
*reg
= NULL
;
475 spin_lock_irq(&rh
->region_lock
);
476 if (!list_empty(&rh
->quiesced_regions
)) {
477 reg
= list_entry(rh
->quiesced_regions
.next
,
478 struct region
, list
);
479 list_del_init(®
->list
); /* remove from the quiesced list */
481 spin_unlock_irq(&rh
->region_lock
);
486 /* FIXME: success ignored for now */
487 static void rh_recovery_end(struct region
*reg
, int success
)
489 struct region_hash
*rh
= reg
->rh
;
491 spin_lock_irq(&rh
->region_lock
);
492 list_add(®
->list
, ®
->rh
->recovered_regions
);
493 spin_unlock_irq(&rh
->region_lock
);
498 static void rh_flush(struct region_hash
*rh
)
500 rh
->log
->type
->flush(rh
->log
);
503 static void rh_delay(struct region_hash
*rh
, struct bio
*bio
)
507 read_lock(&rh
->hash_lock
);
508 reg
= __rh_find(rh
, bio_to_region(rh
, bio
));
509 bio_list_add(®
->delayed_bios
, bio
);
510 read_unlock(&rh
->hash_lock
);
513 static void rh_stop_recovery(struct region_hash
*rh
)
517 /* wait for any recovering regions */
518 for (i
= 0; i
< MAX_RECOVERY
; i
++)
519 down(&rh
->recovery_count
);
522 static void rh_start_recovery(struct region_hash
*rh
)
526 for (i
= 0; i
< MAX_RECOVERY
; i
++)
527 up(&rh
->recovery_count
);
532 /*-----------------------------------------------------------------
533 * Mirror set structures.
534 *---------------------------------------------------------------*/
536 atomic_t error_count
;
542 struct dm_target
*ti
;
543 struct list_head list
;
544 struct region_hash rh
;
545 struct kcopyd_client
*kcopyd_client
;
547 spinlock_t lock
; /* protects the next two lists */
548 struct bio_list reads
;
549 struct bio_list writes
;
555 struct mirror
*default_mirror
; /* Default mirror */
557 unsigned int nr_mirrors
;
558 struct mirror mirror
[0];
562 * Every mirror should look like this one.
564 #define DEFAULT_MIRROR 0
567 * This is yucky. We squirrel the mirror_set struct away inside
568 * bi_next for write buffers. This is safe since the bh
569 * doesn't get submitted to the lower levels of block layer.
571 static struct mirror_set
*bio_get_ms(struct bio
*bio
)
573 return (struct mirror_set
*) bio
->bi_next
;
576 static void bio_set_ms(struct bio
*bio
, struct mirror_set
*ms
)
578 bio
->bi_next
= (struct bio
*) ms
;
581 /*-----------------------------------------------------------------
584 * When a mirror is first activated we may find that some regions
585 * are in the no-sync state. We have to recover these by
586 * recopying from the default mirror to all the others.
587 *---------------------------------------------------------------*/
588 static void recovery_complete(int read_err
, unsigned int write_err
,
591 struct region
*reg
= (struct region
*) context
;
593 /* FIXME: better error handling */
594 rh_recovery_end(reg
, read_err
|| write_err
);
597 static int recover(struct mirror_set
*ms
, struct region
*reg
)
601 struct io_region from
, to
[KCOPYD_MAX_REGIONS
], *dest
;
603 unsigned long flags
= 0;
605 /* fill in the source */
606 m
= ms
->default_mirror
;
607 from
.bdev
= m
->dev
->bdev
;
608 from
.sector
= m
->offset
+ region_to_sector(reg
->rh
, reg
->key
);
609 if (reg
->key
== (ms
->nr_regions
- 1)) {
611 * The final region may be smaller than
614 from
.count
= ms
->ti
->len
& (reg
->rh
->region_size
- 1);
616 from
.count
= reg
->rh
->region_size
;
618 from
.count
= reg
->rh
->region_size
;
620 /* fill in the destinations */
621 for (i
= 0, dest
= to
; i
< ms
->nr_mirrors
; i
++) {
622 if (&ms
->mirror
[i
] == ms
->default_mirror
)
626 dest
->bdev
= m
->dev
->bdev
;
627 dest
->sector
= m
->offset
+ region_to_sector(reg
->rh
, reg
->key
);
628 dest
->count
= from
.count
;
633 set_bit(KCOPYD_IGNORE_ERROR
, &flags
);
634 r
= kcopyd_copy(ms
->kcopyd_client
, &from
, ms
->nr_mirrors
- 1, to
, flags
,
635 recovery_complete
, reg
);
640 static void do_recovery(struct mirror_set
*ms
)
644 struct dirty_log
*log
= ms
->rh
.log
;
647 * Start quiescing some regions.
649 rh_recovery_prepare(&ms
->rh
);
652 * Copy any already quiesced regions.
654 while ((reg
= rh_recovery_start(&ms
->rh
))) {
655 r
= recover(ms
, reg
);
657 rh_recovery_end(reg
, 0);
661 * Update the in sync flag.
664 (log
->type
->get_sync_count(log
) == ms
->nr_regions
)) {
665 /* the sync is complete */
666 dm_table_event(ms
->ti
->table
);
671 /*-----------------------------------------------------------------
673 *---------------------------------------------------------------*/
674 static struct mirror
*choose_mirror(struct mirror_set
*ms
, sector_t sector
)
676 /* FIXME: add read balancing */
677 return ms
->default_mirror
;
681 * remap a buffer to a particular mirror.
683 static void map_bio(struct mirror_set
*ms
, struct mirror
*m
, struct bio
*bio
)
685 bio
->bi_bdev
= m
->dev
->bdev
;
686 bio
->bi_sector
= m
->offset
+ (bio
->bi_sector
- ms
->ti
->begin
);
689 static void do_reads(struct mirror_set
*ms
, struct bio_list
*reads
)
695 while ((bio
= bio_list_pop(reads
))) {
696 region
= bio_to_region(&ms
->rh
, bio
);
699 * We can only read balance if the region is in sync.
701 if (rh_in_sync(&ms
->rh
, region
, 0))
702 m
= choose_mirror(ms
, bio
->bi_sector
);
704 m
= ms
->default_mirror
;
707 generic_make_request(bio
);
711 /*-----------------------------------------------------------------
714 * We do different things with the write io depending on the
715 * state of the region that it's in:
717 * SYNC: increment pending, use kcopyd to write to *all* mirrors
718 * RECOVERING: delay the io until recovery completes
719 * NOSYNC: increment pending, just write to the default mirror
720 *---------------------------------------------------------------*/
721 static void write_callback(unsigned long error
, void *context
)
725 struct bio
*bio
= (struct bio
*) context
;
726 struct mirror_set
*ms
;
728 ms
= bio_get_ms(bio
);
729 bio_set_ms(bio
, NULL
);
732 * NOTE: We don't decrement the pending count here,
733 * instead it is done by the targets endio function.
734 * This way we handle both writes to SYNC and NOSYNC
735 * regions with the same code.
740 * only error the io if all mirrors failed.
744 for (i
= 0; i
< ms
->nr_mirrors
; i
++)
745 if (!test_bit(i
, &error
)) {
750 bio_endio(bio
, bio
->bi_size
, 0);
753 static void do_write(struct mirror_set
*ms
, struct bio
*bio
)
756 struct io_region io
[KCOPYD_MAX_REGIONS
+1];
759 for (i
= 0; i
< ms
->nr_mirrors
; i
++) {
762 io
[i
].bdev
= m
->dev
->bdev
;
763 io
[i
].sector
= m
->offset
+ (bio
->bi_sector
- ms
->ti
->begin
);
764 io
[i
].count
= bio
->bi_size
>> 9;
768 dm_io_async_bvec(ms
->nr_mirrors
, io
, WRITE
,
769 bio
->bi_io_vec
+ bio
->bi_idx
,
770 write_callback
, bio
);
773 static void do_writes(struct mirror_set
*ms
, struct bio_list
*writes
)
777 struct bio_list sync
, nosync
, recover
, *this_list
= NULL
;
783 * Classify each write.
785 bio_list_init(&sync
);
786 bio_list_init(&nosync
);
787 bio_list_init(&recover
);
789 while ((bio
= bio_list_pop(writes
))) {
790 state
= rh_state(&ms
->rh
, bio_to_region(&ms
->rh
, bio
), 1);
802 this_list
= &recover
;
806 bio_list_add(this_list
, bio
);
810 * Increment the pending counts for any regions that will
811 * be written to (writes to recover regions are going to
814 rh_inc_pending(&ms
->rh
, &sync
);
815 rh_inc_pending(&ms
->rh
, &nosync
);
821 while ((bio
= bio_list_pop(&sync
)))
824 while ((bio
= bio_list_pop(&recover
)))
825 rh_delay(&ms
->rh
, bio
);
827 while ((bio
= bio_list_pop(&nosync
))) {
828 map_bio(ms
, ms
->default_mirror
, bio
);
829 generic_make_request(bio
);
833 /*-----------------------------------------------------------------
835 *---------------------------------------------------------------*/
836 static LIST_HEAD(_mirror_sets
);
837 static DECLARE_RWSEM(_mirror_sets_lock
);
839 static void do_mirror(struct mirror_set
*ms
)
841 struct bio_list reads
, writes
;
843 spin_lock(&ms
->lock
);
846 bio_list_init(&ms
->reads
);
847 bio_list_init(&ms
->writes
);
848 spin_unlock(&ms
->lock
);
850 rh_update_states(&ms
->rh
);
852 do_reads(ms
, &reads
);
853 do_writes(ms
, &writes
);
856 static void do_work(void *ignored
)
858 struct mirror_set
*ms
;
860 down_read(&_mirror_sets_lock
);
861 list_for_each_entry (ms
, &_mirror_sets
, list
)
863 up_read(&_mirror_sets_lock
);
866 /*-----------------------------------------------------------------
868 *---------------------------------------------------------------*/
869 static struct mirror_set
*alloc_context(unsigned int nr_mirrors
,
870 uint32_t region_size
,
871 struct dm_target
*ti
,
872 struct dirty_log
*dl
)
875 struct mirror_set
*ms
= NULL
;
877 if (array_too_big(sizeof(*ms
), sizeof(ms
->mirror
[0]), nr_mirrors
))
880 len
= sizeof(*ms
) + (sizeof(ms
->mirror
[0]) * nr_mirrors
);
882 ms
= kmalloc(len
, GFP_KERNEL
);
884 ti
->error
= "dm-mirror: Cannot allocate mirror context";
889 spin_lock_init(&ms
->lock
);
892 ms
->nr_mirrors
= nr_mirrors
;
893 ms
->nr_regions
= dm_sector_div_up(ti
->len
, region_size
);
895 ms
->default_mirror
= &ms
->mirror
[DEFAULT_MIRROR
];
897 if (rh_init(&ms
->rh
, ms
, dl
, region_size
, ms
->nr_regions
)) {
898 ti
->error
= "dm-mirror: Error creating dirty region hash";
906 static void free_context(struct mirror_set
*ms
, struct dm_target
*ti
,
910 dm_put_device(ti
, ms
->mirror
[m
].dev
);
916 static inline int _check_region_size(struct dm_target
*ti
, uint32_t size
)
918 return !(size
% (PAGE_SIZE
>> 9) || (size
& (size
- 1)) ||
922 static int get_mirror(struct mirror_set
*ms
, struct dm_target
*ti
,
923 unsigned int mirror
, char **argv
)
927 if (sscanf(argv
[1], SECTOR_FORMAT
, &offset
) != 1) {
928 ti
->error
= "dm-mirror: Invalid offset";
932 if (dm_get_device(ti
, argv
[0], offset
, ti
->len
,
933 dm_table_get_mode(ti
->table
),
934 &ms
->mirror
[mirror
].dev
)) {
935 ti
->error
= "dm-mirror: Device lookup failure";
939 ms
->mirror
[mirror
].offset
= offset
;
944 static int add_mirror_set(struct mirror_set
*ms
)
946 down_write(&_mirror_sets_lock
);
947 list_add_tail(&ms
->list
, &_mirror_sets
);
948 up_write(&_mirror_sets_lock
);
954 static void del_mirror_set(struct mirror_set
*ms
)
956 down_write(&_mirror_sets_lock
);
958 up_write(&_mirror_sets_lock
);
962 * Create dirty log: log_type #log_params <log_params>
964 static struct dirty_log
*create_dirty_log(struct dm_target
*ti
,
965 unsigned int argc
, char **argv
,
966 unsigned int *args_used
)
968 unsigned int param_count
;
969 struct dirty_log
*dl
;
972 ti
->error
= "dm-mirror: Insufficient mirror log arguments";
976 if (sscanf(argv
[1], "%u", ¶m_count
) != 1) {
977 ti
->error
= "dm-mirror: Invalid mirror log argument count";
981 *args_used
= 2 + param_count
;
983 if (argc
< *args_used
) {
984 ti
->error
= "dm-mirror: Insufficient mirror log arguments";
988 dl
= dm_create_dirty_log(argv
[0], ti
, param_count
, argv
+ 2);
990 ti
->error
= "dm-mirror: Error creating mirror dirty log";
994 if (!_check_region_size(ti
, dl
->type
->get_region_size(dl
))) {
995 ti
->error
= "dm-mirror: Invalid region size";
996 dm_destroy_dirty_log(dl
);
1004 * Construct a mirror mapping:
1006 * log_type #log_params <log_params>
1007 * #mirrors [mirror_path offset]{2,}
1009 * log_type is "core" or "disk"
1010 * #log_params is between 1 and 3
1012 #define DM_IO_PAGES 64
1013 static int mirror_ctr(struct dm_target
*ti
, unsigned int argc
, char **argv
)
1016 unsigned int nr_mirrors
, m
, args_used
;
1017 struct mirror_set
*ms
;
1018 struct dirty_log
*dl
;
1020 dl
= create_dirty_log(ti
, argc
, argv
, &args_used
);
1027 if (!argc
|| sscanf(argv
[0], "%u", &nr_mirrors
) != 1 ||
1028 nr_mirrors
< 2 || nr_mirrors
> KCOPYD_MAX_REGIONS
+ 1) {
1029 ti
->error
= "dm-mirror: Invalid number of mirrors";
1030 dm_destroy_dirty_log(dl
);
1036 if (argc
!= nr_mirrors
* 2) {
1037 ti
->error
= "dm-mirror: Wrong number of mirror arguments";
1038 dm_destroy_dirty_log(dl
);
1042 ms
= alloc_context(nr_mirrors
, dl
->type
->get_region_size(dl
), ti
, dl
);
1044 dm_destroy_dirty_log(dl
);
1048 /* Get the mirror parameter sets */
1049 for (m
= 0; m
< nr_mirrors
; m
++) {
1050 r
= get_mirror(ms
, ti
, m
, argv
);
1052 free_context(ms
, ti
, m
);
1060 ti
->split_io
= ms
->rh
.region_size
;
1062 r
= kcopyd_client_create(DM_IO_PAGES
, &ms
->kcopyd_client
);
1064 free_context(ms
, ti
, ms
->nr_mirrors
);
1072 static void mirror_dtr(struct dm_target
*ti
)
1074 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1077 kcopyd_client_destroy(ms
->kcopyd_client
);
1078 free_context(ms
, ti
, ms
->nr_mirrors
);
1081 static void queue_bio(struct mirror_set
*ms
, struct bio
*bio
, int rw
)
1083 int should_wake
= 0;
1084 struct bio_list
*bl
;
1086 bl
= (rw
== WRITE
) ? &ms
->writes
: &ms
->reads
;
1087 spin_lock(&ms
->lock
);
1088 should_wake
= !(bl
->head
);
1089 bio_list_add(bl
, bio
);
1090 spin_unlock(&ms
->lock
);
1097 * Mirror mapping function
1099 static int mirror_map(struct dm_target
*ti
, struct bio
*bio
,
1100 union map_info
*map_context
)
1102 int r
, rw
= bio_rw(bio
);
1104 struct mirror_set
*ms
= ti
->private;
1106 map_context
->ll
= bio
->bi_sector
>> ms
->rh
.region_shift
;
1109 queue_bio(ms
, bio
, rw
);
1113 r
= ms
->rh
.log
->type
->in_sync(ms
->rh
.log
,
1114 bio_to_region(&ms
->rh
, bio
), 0);
1115 if (r
< 0 && r
!= -EWOULDBLOCK
)
1118 if (r
== -EWOULDBLOCK
) /* FIXME: ugly */
1122 * We don't want to fast track a recovery just for a read
1123 * ahead. So we just let it silently fail.
1124 * FIXME: get rid of this.
1126 if (!r
&& rw
== READA
)
1130 /* Pass this io over to the daemon */
1131 queue_bio(ms
, bio
, rw
);
1135 m
= choose_mirror(ms
, bio
->bi_sector
);
1139 map_bio(ms
, m
, bio
);
1143 static int mirror_end_io(struct dm_target
*ti
, struct bio
*bio
,
1144 int error
, union map_info
*map_context
)
1146 int rw
= bio_rw(bio
);
1147 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1148 region_t region
= map_context
->ll
;
1151 * We need to dec pending if this was a write.
1154 rh_dec(&ms
->rh
, region
);
1159 static void mirror_postsuspend(struct dm_target
*ti
)
1161 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1162 struct dirty_log
*log
= ms
->rh
.log
;
1164 rh_stop_recovery(&ms
->rh
);
1165 if (log
->type
->suspend
&& log
->type
->suspend(log
))
1166 /* FIXME: need better error handling */
1167 DMWARN("log suspend failed");
1170 static void mirror_resume(struct dm_target
*ti
)
1172 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1173 struct dirty_log
*log
= ms
->rh
.log
;
1174 if (log
->type
->resume
&& log
->type
->resume(log
))
1175 /* FIXME: need better error handling */
1176 DMWARN("log resume failed");
1177 rh_start_recovery(&ms
->rh
);
1180 static int mirror_status(struct dm_target
*ti
, status_type_t type
,
1181 char *result
, unsigned int maxlen
)
1184 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1186 sz
= ms
->rh
.log
->type
->status(ms
->rh
.log
, type
, result
, maxlen
);
1189 case STATUSTYPE_INFO
:
1190 DMEMIT("%d ", ms
->nr_mirrors
);
1191 for (m
= 0; m
< ms
->nr_mirrors
; m
++)
1192 DMEMIT("%s ", ms
->mirror
[m
].dev
->name
);
1194 DMEMIT(SECTOR_FORMAT
"/" SECTOR_FORMAT
,
1195 ms
->rh
.log
->type
->get_sync_count(ms
->rh
.log
),
1199 case STATUSTYPE_TABLE
:
1200 DMEMIT("%d ", ms
->nr_mirrors
);
1201 for (m
= 0; m
< ms
->nr_mirrors
; m
++)
1202 DMEMIT("%s " SECTOR_FORMAT
" ",
1203 ms
->mirror
[m
].dev
->name
, ms
->mirror
[m
].offset
);
1209 static struct target_type mirror_target
= {
1211 .version
= {1, 0, 1},
1212 .module
= THIS_MODULE
,
1216 .end_io
= mirror_end_io
,
1217 .postsuspend
= mirror_postsuspend
,
1218 .resume
= mirror_resume
,
1219 .status
= mirror_status
,
1222 static int __init
dm_mirror_init(void)
1226 r
= dm_dirty_log_init();
1230 _kmirrord_wq
= create_singlethread_workqueue("kmirrord");
1231 if (!_kmirrord_wq
) {
1232 DMERR("couldn't start kmirrord");
1233 dm_dirty_log_exit();
1236 INIT_WORK(&_kmirrord_work
, do_work
, NULL
);
1238 r
= dm_register_target(&mirror_target
);
1240 DMERR("%s: Failed to register mirror target",
1241 mirror_target
.name
);
1242 dm_dirty_log_exit();
1243 destroy_workqueue(_kmirrord_wq
);
1249 static void __exit
dm_mirror_exit(void)
1253 r
= dm_unregister_target(&mirror_target
);
1255 DMERR("%s: unregister failed %d", mirror_target
.name
, r
);
1257 destroy_workqueue(_kmirrord_wq
);
1258 dm_dirty_log_exit();
1262 module_init(dm_mirror_init
);
1263 module_exit(dm_mirror_exit
);
1265 MODULE_DESCRIPTION(DM_NAME
" mirror target");
1266 MODULE_AUTHOR("Joe Thornber");
1267 MODULE_LICENSE("GPL");