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
)) {
406 * There is no pending I/O for this region.
407 * We can move the region to corresponding list for next action.
408 * At this point, the region is not yet connected to any list.
410 * If the state is RH_NOSYNC, the region should be kept off
412 * The hash entry for RH_NOSYNC will remain in memory
413 * until the region is recovered or the map is reloaded.
416 /* do nothing for RH_NOSYNC */
417 if (reg
->state
== RH_RECOVERING
) {
418 list_add_tail(®
->list
, &rh
->quiesced_regions
);
419 } else if (reg
->state
== RH_DIRTY
) {
420 reg
->state
= RH_CLEAN
;
421 list_add(®
->list
, &rh
->clean_regions
);
425 spin_unlock_irqrestore(&rh
->region_lock
, flags
);
432 * Starts quiescing a region in preparation for recovery.
434 static int __rh_recovery_prepare(struct region_hash
*rh
)
441 * Ask the dirty log what's next.
443 r
= rh
->log
->type
->get_resync_work(rh
->log
, ®ion
);
448 * Get this region, and start it quiescing by setting the
451 read_lock(&rh
->hash_lock
);
452 reg
= __rh_find(rh
, region
);
453 read_unlock(&rh
->hash_lock
);
455 spin_lock_irq(&rh
->region_lock
);
456 reg
->state
= RH_RECOVERING
;
458 /* Already quiesced ? */
459 if (atomic_read(®
->pending
))
460 list_del_init(®
->list
);
463 list_del_init(®
->list
);
464 list_add(®
->list
, &rh
->quiesced_regions
);
466 spin_unlock_irq(&rh
->region_lock
);
471 static void rh_recovery_prepare(struct region_hash
*rh
)
473 while (!down_trylock(&rh
->recovery_count
))
474 if (__rh_recovery_prepare(rh
) <= 0) {
475 up(&rh
->recovery_count
);
481 * Returns any quiesced regions.
483 static struct region
*rh_recovery_start(struct region_hash
*rh
)
485 struct region
*reg
= NULL
;
487 spin_lock_irq(&rh
->region_lock
);
488 if (!list_empty(&rh
->quiesced_regions
)) {
489 reg
= list_entry(rh
->quiesced_regions
.next
,
490 struct region
, list
);
491 list_del_init(®
->list
); /* remove from the quiesced list */
493 spin_unlock_irq(&rh
->region_lock
);
498 /* FIXME: success ignored for now */
499 static void rh_recovery_end(struct region
*reg
, int success
)
501 struct region_hash
*rh
= reg
->rh
;
503 spin_lock_irq(&rh
->region_lock
);
504 list_add(®
->list
, ®
->rh
->recovered_regions
);
505 spin_unlock_irq(&rh
->region_lock
);
510 static void rh_flush(struct region_hash
*rh
)
512 rh
->log
->type
->flush(rh
->log
);
515 static void rh_delay(struct region_hash
*rh
, struct bio
*bio
)
519 read_lock(&rh
->hash_lock
);
520 reg
= __rh_find(rh
, bio_to_region(rh
, bio
));
521 bio_list_add(®
->delayed_bios
, bio
);
522 read_unlock(&rh
->hash_lock
);
525 static void rh_stop_recovery(struct region_hash
*rh
)
529 /* wait for any recovering regions */
530 for (i
= 0; i
< MAX_RECOVERY
; i
++)
531 down(&rh
->recovery_count
);
534 static void rh_start_recovery(struct region_hash
*rh
)
538 for (i
= 0; i
< MAX_RECOVERY
; i
++)
539 up(&rh
->recovery_count
);
544 /*-----------------------------------------------------------------
545 * Mirror set structures.
546 *---------------------------------------------------------------*/
548 atomic_t error_count
;
554 struct dm_target
*ti
;
555 struct list_head list
;
556 struct region_hash rh
;
557 struct kcopyd_client
*kcopyd_client
;
559 spinlock_t lock
; /* protects the next two lists */
560 struct bio_list reads
;
561 struct bio_list writes
;
567 struct mirror
*default_mirror
; /* Default mirror */
569 unsigned int nr_mirrors
;
570 struct mirror mirror
[0];
574 * Every mirror should look like this one.
576 #define DEFAULT_MIRROR 0
579 * This is yucky. We squirrel the mirror_set struct away inside
580 * bi_next for write buffers. This is safe since the bh
581 * doesn't get submitted to the lower levels of block layer.
583 static struct mirror_set
*bio_get_ms(struct bio
*bio
)
585 return (struct mirror_set
*) bio
->bi_next
;
588 static void bio_set_ms(struct bio
*bio
, struct mirror_set
*ms
)
590 bio
->bi_next
= (struct bio
*) ms
;
593 /*-----------------------------------------------------------------
596 * When a mirror is first activated we may find that some regions
597 * are in the no-sync state. We have to recover these by
598 * recopying from the default mirror to all the others.
599 *---------------------------------------------------------------*/
600 static void recovery_complete(int read_err
, unsigned int write_err
,
603 struct region
*reg
= (struct region
*) context
;
605 /* FIXME: better error handling */
606 rh_recovery_end(reg
, read_err
|| write_err
);
609 static int recover(struct mirror_set
*ms
, struct region
*reg
)
613 struct io_region from
, to
[KCOPYD_MAX_REGIONS
], *dest
;
615 unsigned long flags
= 0;
617 /* fill in the source */
618 m
= ms
->default_mirror
;
619 from
.bdev
= m
->dev
->bdev
;
620 from
.sector
= m
->offset
+ region_to_sector(reg
->rh
, reg
->key
);
621 if (reg
->key
== (ms
->nr_regions
- 1)) {
623 * The final region may be smaller than
626 from
.count
= ms
->ti
->len
& (reg
->rh
->region_size
- 1);
628 from
.count
= reg
->rh
->region_size
;
630 from
.count
= reg
->rh
->region_size
;
632 /* fill in the destinations */
633 for (i
= 0, dest
= to
; i
< ms
->nr_mirrors
; i
++) {
634 if (&ms
->mirror
[i
] == ms
->default_mirror
)
638 dest
->bdev
= m
->dev
->bdev
;
639 dest
->sector
= m
->offset
+ region_to_sector(reg
->rh
, reg
->key
);
640 dest
->count
= from
.count
;
645 set_bit(KCOPYD_IGNORE_ERROR
, &flags
);
646 r
= kcopyd_copy(ms
->kcopyd_client
, &from
, ms
->nr_mirrors
- 1, to
, flags
,
647 recovery_complete
, reg
);
652 static void do_recovery(struct mirror_set
*ms
)
656 struct dirty_log
*log
= ms
->rh
.log
;
659 * Start quiescing some regions.
661 rh_recovery_prepare(&ms
->rh
);
664 * Copy any already quiesced regions.
666 while ((reg
= rh_recovery_start(&ms
->rh
))) {
667 r
= recover(ms
, reg
);
669 rh_recovery_end(reg
, 0);
673 * Update the in sync flag.
676 (log
->type
->get_sync_count(log
) == ms
->nr_regions
)) {
677 /* the sync is complete */
678 dm_table_event(ms
->ti
->table
);
683 /*-----------------------------------------------------------------
685 *---------------------------------------------------------------*/
686 static struct mirror
*choose_mirror(struct mirror_set
*ms
, sector_t sector
)
688 /* FIXME: add read balancing */
689 return ms
->default_mirror
;
693 * remap a buffer to a particular mirror.
695 static void map_bio(struct mirror_set
*ms
, struct mirror
*m
, struct bio
*bio
)
697 bio
->bi_bdev
= m
->dev
->bdev
;
698 bio
->bi_sector
= m
->offset
+ (bio
->bi_sector
- ms
->ti
->begin
);
701 static void do_reads(struct mirror_set
*ms
, struct bio_list
*reads
)
707 while ((bio
= bio_list_pop(reads
))) {
708 region
= bio_to_region(&ms
->rh
, bio
);
711 * We can only read balance if the region is in sync.
713 if (rh_in_sync(&ms
->rh
, region
, 0))
714 m
= choose_mirror(ms
, bio
->bi_sector
);
716 m
= ms
->default_mirror
;
719 generic_make_request(bio
);
723 /*-----------------------------------------------------------------
726 * We do different things with the write io depending on the
727 * state of the region that it's in:
729 * SYNC: increment pending, use kcopyd to write to *all* mirrors
730 * RECOVERING: delay the io until recovery completes
731 * NOSYNC: increment pending, just write to the default mirror
732 *---------------------------------------------------------------*/
733 static void write_callback(unsigned long error
, void *context
)
737 struct bio
*bio
= (struct bio
*) context
;
738 struct mirror_set
*ms
;
740 ms
= bio_get_ms(bio
);
741 bio_set_ms(bio
, NULL
);
744 * NOTE: We don't decrement the pending count here,
745 * instead it is done by the targets endio function.
746 * This way we handle both writes to SYNC and NOSYNC
747 * regions with the same code.
752 * only error the io if all mirrors failed.
756 for (i
= 0; i
< ms
->nr_mirrors
; i
++)
757 if (!test_bit(i
, &error
)) {
762 bio_endio(bio
, bio
->bi_size
, 0);
765 static void do_write(struct mirror_set
*ms
, struct bio
*bio
)
768 struct io_region io
[KCOPYD_MAX_REGIONS
+1];
771 for (i
= 0; i
< ms
->nr_mirrors
; i
++) {
774 io
[i
].bdev
= m
->dev
->bdev
;
775 io
[i
].sector
= m
->offset
+ (bio
->bi_sector
- ms
->ti
->begin
);
776 io
[i
].count
= bio
->bi_size
>> 9;
780 dm_io_async_bvec(ms
->nr_mirrors
, io
, WRITE
,
781 bio
->bi_io_vec
+ bio
->bi_idx
,
782 write_callback
, bio
);
785 static void do_writes(struct mirror_set
*ms
, struct bio_list
*writes
)
789 struct bio_list sync
, nosync
, recover
, *this_list
= NULL
;
795 * Classify each write.
797 bio_list_init(&sync
);
798 bio_list_init(&nosync
);
799 bio_list_init(&recover
);
801 while ((bio
= bio_list_pop(writes
))) {
802 state
= rh_state(&ms
->rh
, bio_to_region(&ms
->rh
, bio
), 1);
814 this_list
= &recover
;
818 bio_list_add(this_list
, bio
);
822 * Increment the pending counts for any regions that will
823 * be written to (writes to recover regions are going to
826 rh_inc_pending(&ms
->rh
, &sync
);
827 rh_inc_pending(&ms
->rh
, &nosync
);
833 while ((bio
= bio_list_pop(&sync
)))
836 while ((bio
= bio_list_pop(&recover
)))
837 rh_delay(&ms
->rh
, bio
);
839 while ((bio
= bio_list_pop(&nosync
))) {
840 map_bio(ms
, ms
->default_mirror
, bio
);
841 generic_make_request(bio
);
845 /*-----------------------------------------------------------------
847 *---------------------------------------------------------------*/
848 static LIST_HEAD(_mirror_sets
);
849 static DECLARE_RWSEM(_mirror_sets_lock
);
851 static void do_mirror(struct mirror_set
*ms
)
853 struct bio_list reads
, writes
;
855 spin_lock(&ms
->lock
);
858 bio_list_init(&ms
->reads
);
859 bio_list_init(&ms
->writes
);
860 spin_unlock(&ms
->lock
);
862 rh_update_states(&ms
->rh
);
864 do_reads(ms
, &reads
);
865 do_writes(ms
, &writes
);
868 static void do_work(void *ignored
)
870 struct mirror_set
*ms
;
872 down_read(&_mirror_sets_lock
);
873 list_for_each_entry (ms
, &_mirror_sets
, list
)
875 up_read(&_mirror_sets_lock
);
878 /*-----------------------------------------------------------------
880 *---------------------------------------------------------------*/
881 static struct mirror_set
*alloc_context(unsigned int nr_mirrors
,
882 uint32_t region_size
,
883 struct dm_target
*ti
,
884 struct dirty_log
*dl
)
887 struct mirror_set
*ms
= NULL
;
889 if (array_too_big(sizeof(*ms
), sizeof(ms
->mirror
[0]), nr_mirrors
))
892 len
= sizeof(*ms
) + (sizeof(ms
->mirror
[0]) * nr_mirrors
);
894 ms
= kmalloc(len
, GFP_KERNEL
);
896 ti
->error
= "dm-mirror: Cannot allocate mirror context";
901 spin_lock_init(&ms
->lock
);
904 ms
->nr_mirrors
= nr_mirrors
;
905 ms
->nr_regions
= dm_sector_div_up(ti
->len
, region_size
);
907 ms
->default_mirror
= &ms
->mirror
[DEFAULT_MIRROR
];
909 if (rh_init(&ms
->rh
, ms
, dl
, region_size
, ms
->nr_regions
)) {
910 ti
->error
= "dm-mirror: Error creating dirty region hash";
918 static void free_context(struct mirror_set
*ms
, struct dm_target
*ti
,
922 dm_put_device(ti
, ms
->mirror
[m
].dev
);
928 static inline int _check_region_size(struct dm_target
*ti
, uint32_t size
)
930 return !(size
% (PAGE_SIZE
>> 9) || (size
& (size
- 1)) ||
934 static int get_mirror(struct mirror_set
*ms
, struct dm_target
*ti
,
935 unsigned int mirror
, char **argv
)
937 unsigned long long offset
;
939 if (sscanf(argv
[1], "%llu", &offset
) != 1) {
940 ti
->error
= "dm-mirror: Invalid offset";
944 if (dm_get_device(ti
, argv
[0], offset
, ti
->len
,
945 dm_table_get_mode(ti
->table
),
946 &ms
->mirror
[mirror
].dev
)) {
947 ti
->error
= "dm-mirror: Device lookup failure";
951 ms
->mirror
[mirror
].offset
= offset
;
956 static int add_mirror_set(struct mirror_set
*ms
)
958 down_write(&_mirror_sets_lock
);
959 list_add_tail(&ms
->list
, &_mirror_sets
);
960 up_write(&_mirror_sets_lock
);
966 static void del_mirror_set(struct mirror_set
*ms
)
968 down_write(&_mirror_sets_lock
);
970 up_write(&_mirror_sets_lock
);
974 * Create dirty log: log_type #log_params <log_params>
976 static struct dirty_log
*create_dirty_log(struct dm_target
*ti
,
977 unsigned int argc
, char **argv
,
978 unsigned int *args_used
)
980 unsigned int param_count
;
981 struct dirty_log
*dl
;
984 ti
->error
= "dm-mirror: Insufficient mirror log arguments";
988 if (sscanf(argv
[1], "%u", ¶m_count
) != 1) {
989 ti
->error
= "dm-mirror: Invalid mirror log argument count";
993 *args_used
= 2 + param_count
;
995 if (argc
< *args_used
) {
996 ti
->error
= "dm-mirror: Insufficient mirror log arguments";
1000 dl
= dm_create_dirty_log(argv
[0], ti
, param_count
, argv
+ 2);
1002 ti
->error
= "dm-mirror: Error creating mirror dirty log";
1006 if (!_check_region_size(ti
, dl
->type
->get_region_size(dl
))) {
1007 ti
->error
= "dm-mirror: Invalid region size";
1008 dm_destroy_dirty_log(dl
);
1016 * Construct a mirror mapping:
1018 * log_type #log_params <log_params>
1019 * #mirrors [mirror_path offset]{2,}
1021 * log_type is "core" or "disk"
1022 * #log_params is between 1 and 3
1024 #define DM_IO_PAGES 64
1025 static int mirror_ctr(struct dm_target
*ti
, unsigned int argc
, char **argv
)
1028 unsigned int nr_mirrors
, m
, args_used
;
1029 struct mirror_set
*ms
;
1030 struct dirty_log
*dl
;
1032 dl
= create_dirty_log(ti
, argc
, argv
, &args_used
);
1039 if (!argc
|| sscanf(argv
[0], "%u", &nr_mirrors
) != 1 ||
1040 nr_mirrors
< 2 || nr_mirrors
> KCOPYD_MAX_REGIONS
+ 1) {
1041 ti
->error
= "dm-mirror: Invalid number of mirrors";
1042 dm_destroy_dirty_log(dl
);
1048 if (argc
!= nr_mirrors
* 2) {
1049 ti
->error
= "dm-mirror: Wrong number of mirror arguments";
1050 dm_destroy_dirty_log(dl
);
1054 ms
= alloc_context(nr_mirrors
, dl
->type
->get_region_size(dl
), ti
, dl
);
1056 dm_destroy_dirty_log(dl
);
1060 /* Get the mirror parameter sets */
1061 for (m
= 0; m
< nr_mirrors
; m
++) {
1062 r
= get_mirror(ms
, ti
, m
, argv
);
1064 free_context(ms
, ti
, m
);
1072 ti
->split_io
= ms
->rh
.region_size
;
1074 r
= kcopyd_client_create(DM_IO_PAGES
, &ms
->kcopyd_client
);
1076 free_context(ms
, ti
, ms
->nr_mirrors
);
1084 static void mirror_dtr(struct dm_target
*ti
)
1086 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1089 kcopyd_client_destroy(ms
->kcopyd_client
);
1090 free_context(ms
, ti
, ms
->nr_mirrors
);
1093 static void queue_bio(struct mirror_set
*ms
, struct bio
*bio
, int rw
)
1095 int should_wake
= 0;
1096 struct bio_list
*bl
;
1098 bl
= (rw
== WRITE
) ? &ms
->writes
: &ms
->reads
;
1099 spin_lock(&ms
->lock
);
1100 should_wake
= !(bl
->head
);
1101 bio_list_add(bl
, bio
);
1102 spin_unlock(&ms
->lock
);
1109 * Mirror mapping function
1111 static int mirror_map(struct dm_target
*ti
, struct bio
*bio
,
1112 union map_info
*map_context
)
1114 int r
, rw
= bio_rw(bio
);
1116 struct mirror_set
*ms
= ti
->private;
1118 map_context
->ll
= bio
->bi_sector
>> ms
->rh
.region_shift
;
1121 queue_bio(ms
, bio
, rw
);
1125 r
= ms
->rh
.log
->type
->in_sync(ms
->rh
.log
,
1126 bio_to_region(&ms
->rh
, bio
), 0);
1127 if (r
< 0 && r
!= -EWOULDBLOCK
)
1130 if (r
== -EWOULDBLOCK
) /* FIXME: ugly */
1134 * We don't want to fast track a recovery just for a read
1135 * ahead. So we just let it silently fail.
1136 * FIXME: get rid of this.
1138 if (!r
&& rw
== READA
)
1142 /* Pass this io over to the daemon */
1143 queue_bio(ms
, bio
, rw
);
1147 m
= choose_mirror(ms
, bio
->bi_sector
);
1151 map_bio(ms
, m
, bio
);
1155 static int mirror_end_io(struct dm_target
*ti
, struct bio
*bio
,
1156 int error
, union map_info
*map_context
)
1158 int rw
= bio_rw(bio
);
1159 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1160 region_t region
= map_context
->ll
;
1163 * We need to dec pending if this was a write.
1166 rh_dec(&ms
->rh
, region
);
1171 static void mirror_postsuspend(struct dm_target
*ti
)
1173 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1174 struct dirty_log
*log
= ms
->rh
.log
;
1176 rh_stop_recovery(&ms
->rh
);
1177 if (log
->type
->suspend
&& log
->type
->suspend(log
))
1178 /* FIXME: need better error handling */
1179 DMWARN("log suspend failed");
1182 static void mirror_resume(struct dm_target
*ti
)
1184 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1185 struct dirty_log
*log
= ms
->rh
.log
;
1186 if (log
->type
->resume
&& log
->type
->resume(log
))
1187 /* FIXME: need better error handling */
1188 DMWARN("log resume failed");
1189 rh_start_recovery(&ms
->rh
);
1192 static int mirror_status(struct dm_target
*ti
, status_type_t type
,
1193 char *result
, unsigned int maxlen
)
1196 struct mirror_set
*ms
= (struct mirror_set
*) ti
->private;
1198 sz
= ms
->rh
.log
->type
->status(ms
->rh
.log
, type
, result
, maxlen
);
1201 case STATUSTYPE_INFO
:
1202 DMEMIT("%d ", ms
->nr_mirrors
);
1203 for (m
= 0; m
< ms
->nr_mirrors
; m
++)
1204 DMEMIT("%s ", ms
->mirror
[m
].dev
->name
);
1207 (unsigned long long)ms
->rh
.log
->type
->
1208 get_sync_count(ms
->rh
.log
),
1209 (unsigned long long)ms
->nr_regions
);
1212 case STATUSTYPE_TABLE
:
1213 DMEMIT("%d ", ms
->nr_mirrors
);
1214 for (m
= 0; m
< ms
->nr_mirrors
; m
++)
1215 DMEMIT("%s %llu ", ms
->mirror
[m
].dev
->name
,
1216 (unsigned long long)ms
->mirror
[m
].offset
);
1222 static struct target_type mirror_target
= {
1224 .version
= {1, 0, 1},
1225 .module
= THIS_MODULE
,
1229 .end_io
= mirror_end_io
,
1230 .postsuspend
= mirror_postsuspend
,
1231 .resume
= mirror_resume
,
1232 .status
= mirror_status
,
1235 static int __init
dm_mirror_init(void)
1239 r
= dm_dirty_log_init();
1243 _kmirrord_wq
= create_singlethread_workqueue("kmirrord");
1244 if (!_kmirrord_wq
) {
1245 DMERR("couldn't start kmirrord");
1246 dm_dirty_log_exit();
1249 INIT_WORK(&_kmirrord_work
, do_work
, NULL
);
1251 r
= dm_register_target(&mirror_target
);
1253 DMERR("%s: Failed to register mirror target",
1254 mirror_target
.name
);
1255 dm_dirty_log_exit();
1256 destroy_workqueue(_kmirrord_wq
);
1262 static void __exit
dm_mirror_exit(void)
1266 r
= dm_unregister_target(&mirror_target
);
1268 DMERR("%s: unregister failed %d", mirror_target
.name
, r
);
1270 destroy_workqueue(_kmirrord_wq
);
1271 dm_dirty_log_exit();
1275 module_init(dm_mirror_init
);
1276 module_exit(dm_mirror_exit
);
1278 MODULE_DESCRIPTION(DM_NAME
" mirror target");
1279 MODULE_AUTHOR("Joe Thornber");
1280 MODULE_LICENSE("GPL");