Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'dm-3.9-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm
Pull device-mapper fixes from Alasdair Kergon:
"A pair of patches to fix the writethrough mode of the device-mapper
cache target when the device being cached is not itself wrapped with
device-mapper."
* tag 'dm-3.9-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
dm cache: reduce bio front_pad size in writeback mode
dm cache: fix writes to cache device in writethrough mode
+38
-13
+38
-13
drivers/md/dm-cache-target.c
+38
-13
drivers/md/dm-cache-target.c
···
6
6
7
7
#include "dm.h"
8
8
#include "dm-bio-prison.h"
9
+
#include "dm-bio-record.h"
9
10
#include "dm-cache-metadata.h"
10
11
11
12
#include <linux/dm-io.h>
···
202
201
unsigned req_nr:2;
203
202
struct dm_deferred_entry *all_io_entry;
204
203
205
-
/* writethrough fields */
204
+
/*
205
+
* writethrough fields. These MUST remain at the end of this
206
+
* structure and the 'cache' member must be the first as it
207
+
* is used to determine the offsetof the writethrough fields.
208
+
*/
206
209
struct cache *cache;
207
210
dm_cblock_t cblock;
208
211
bio_end_io_t *saved_bi_end_io;
212
+
struct dm_bio_details bio_details;
209
213
};
210
214
211
215
struct dm_cache_migration {
···
519
513
/*----------------------------------------------------------------
520
514
* Per bio data
521
515
*--------------------------------------------------------------*/
522
-
static struct per_bio_data *get_per_bio_data(struct bio *bio)
516
+
517
+
/*
518
+
* If using writeback, leave out struct per_bio_data's writethrough fields.
519
+
*/
520
+
#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))
521
+
#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))
522
+
523
+
static size_t get_per_bio_data_size(struct cache *cache)
523
524
{
524
-
struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
525
+
return cache->features.write_through ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;
526
+
}
527
+
528
+
static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)
529
+
{
530
+
struct per_bio_data *pb = dm_per_bio_data(bio, data_size);
525
531
BUG_ON(!pb);
526
532
return pb;
527
533
}
528
534
529
-
static struct per_bio_data *init_per_bio_data(struct bio *bio)
535
+
static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)
530
536
{
531
-
struct per_bio_data *pb = get_per_bio_data(bio);
537
+
struct per_bio_data *pb = get_per_bio_data(bio, data_size);
532
538
533
539
pb->tick = false;
534
540
pb->req_nr = dm_bio_get_target_bio_nr(bio);
···
574
556
static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
575
557
{
576
558
unsigned long flags;
577
-
struct per_bio_data *pb = get_per_bio_data(bio);
559
+
size_t pb_data_size = get_per_bio_data_size(cache);
560
+
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
578
561
579
562
spin_lock_irqsave(&cache->lock, flags);
580
563
if (cache->need_tick_bio &&
···
654
635
655
636
static void writethrough_endio(struct bio *bio, int err)
656
637
{
657
-
struct per_bio_data *pb = get_per_bio_data(bio);
638
+
struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
658
639
bio->bi_end_io = pb->saved_bi_end_io;
659
640
660
641
if (err) {
···
662
643
return;
663
644
}
664
645
646
+
dm_bio_restore(&pb->bio_details, bio);
665
647
remap_to_cache(pb->cache, bio, pb->cblock);
666
648
667
649
/*
···
682
662
static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
683
663
dm_oblock_t oblock, dm_cblock_t cblock)
684
664
{
685
-
struct per_bio_data *pb = get_per_bio_data(bio);
665
+
struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
686
666
687
667
pb->cache = cache;
688
668
pb->cblock = cblock;
689
669
pb->saved_bi_end_io = bio->bi_end_io;
670
+
dm_bio_record(&pb->bio_details, bio);
690
671
bio->bi_end_io = writethrough_endio;
691
672
692
673
remap_to_origin_clear_discard(pb->cache, bio, oblock);
···
1056
1035
1057
1036
static void process_flush_bio(struct cache *cache, struct bio *bio)
1058
1037
{
1059
-
struct per_bio_data *pb = get_per_bio_data(bio);
1038
+
size_t pb_data_size = get_per_bio_data_size(cache);
1039
+
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1060
1040
1061
1041
BUG_ON(bio->bi_size);
1062
1042
if (!pb->req_nr)
···
1129
1107
dm_oblock_t block = get_bio_block(cache, bio);
1130
1108
struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;
1131
1109
struct policy_result lookup_result;
1132
-
struct per_bio_data *pb = get_per_bio_data(bio);
1110
+
size_t pb_data_size = get_per_bio_data_size(cache);
1111
+
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1133
1112
bool discarded_block = is_discarded_oblock(cache, block);
1134
1113
bool can_migrate = discarded_block || spare_migration_bandwidth(cache);
1135
1114
···
1904
1881
1905
1882
cache->ti = ca->ti;
1906
1883
ti->private = cache;
1907
-
ti->per_bio_data_size = sizeof(struct per_bio_data);
1908
1884
ti->num_flush_bios = 2;
1909
1885
ti->flush_supported = true;
1910
1886
···
1912
1890
ti->discard_zeroes_data_unsupported = true;
1913
1891
1914
1892
memcpy(&cache->features, &ca->features, sizeof(cache->features));
1893
+
ti->per_bio_data_size = get_per_bio_data_size(cache);
1915
1894
1916
1895
cache->callbacks.congested_fn = cache_is_congested;
1917
1896
dm_table_add_target_callbacks(ti->table, &cache->callbacks);
···
2115
2092
2116
2093
int r;
2117
2094
dm_oblock_t block = get_bio_block(cache, bio);
2095
+
size_t pb_data_size = get_per_bio_data_size(cache);
2118
2096
bool can_migrate = false;
2119
2097
bool discarded_block;
2120
2098
struct dm_bio_prison_cell *cell;
···
2132
2108
return DM_MAPIO_REMAPPED;
2133
2109
}
2134
2110
2135
-
pb = init_per_bio_data(bio);
2111
+
pb = init_per_bio_data(bio, pb_data_size);
2136
2112
2137
2113
if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) {
2138
2114
defer_bio(cache, bio);
···
2217
2193
{
2218
2194
struct cache *cache = ti->private;
2219
2195
unsigned long flags;
2220
-
struct per_bio_data *pb = get_per_bio_data(bio);
2196
+
size_t pb_data_size = get_per_bio_data_size(cache);
2197
+
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
2221
2198
2222
2199
if (pb->tick) {
2223
2200
policy_tick(cache->policy);