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Commit fe696909 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents b196553a 19b0092e

drivers/md/dm-cache-target.c

+38 −13
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 


#include "dm.h"

#include "dm-bio-prison.h"

#include "dm-bio-record.h"

#include "dm-cache-metadata.h"



#include <linux/dm-io.h>
@@ -201,10 +202,15 @@ struct per_bio_data { 
	unsigned req_nr:2;

	struct dm_deferred_entry *all_io_entry;



	/* writethrough fields */

	/*

	 * writethrough fields.  These MUST remain at the end of this

	 * structure and the 'cache' member must be the first as it

	 * is used to determine the offsetof the writethrough fields.

	 */

	struct cache *cache;

	dm_cblock_t cblock;

	bio_end_io_t *saved_bi_end_io;

	struct dm_bio_details bio_details;

};



struct dm_cache_migration {
@@ -513,16 +519,28 @@ static void save_stats(struct cache *cache) 
/*----------------------------------------------------------------

 * Per bio data

 *--------------------------------------------------------------*/

static struct per_bio_data *get_per_bio_data(struct bio *bio)



/*

 * If using writeback, leave out struct per_bio_data's writethrough fields.

 */

#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))

#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))



static size_t get_per_bio_data_size(struct cache *cache)

{

	return cache->features.write_through ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;

}



static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)

{

	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));

	struct per_bio_data *pb = dm_per_bio_data(bio, data_size);

	BUG_ON(!pb);

	return pb;

}



static struct per_bio_data *init_per_bio_data(struct bio *bio)

static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)

{

	struct per_bio_data *pb = get_per_bio_data(bio);

	struct per_bio_data *pb = get_per_bio_data(bio, data_size);



	pb->tick = false;

	pb->req_nr = dm_bio_get_target_bio_nr(bio);
@@ -556,7 +574,8 @@ static void remap_to_cache(struct cache *cache, struct bio *bio, 
static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)

{

	unsigned long flags;

	struct per_bio_data *pb = get_per_bio_data(bio);

	size_t pb_data_size = get_per_bio_data_size(cache);

	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);



	spin_lock_irqsave(&cache->lock, flags);

	if (cache->need_tick_bio &&
@@ -635,7 +654,7 @@ static void defer_writethrough_bio(struct cache *cache, struct bio *bio) 


static void writethrough_endio(struct bio *bio, int err)

{

	struct per_bio_data *pb = get_per_bio_data(bio);

	struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);

	bio->bi_end_io = pb->saved_bi_end_io;



	if (err) {
@@ -643,6 +662,7 @@ static void writethrough_endio(struct bio *bio, int err) 
		return;

	}



	dm_bio_restore(&pb->bio_details, bio);

	remap_to_cache(pb->cache, bio, pb->cblock);



	/*
@@ -662,11 +682,12 @@ static void writethrough_endio(struct bio *bio, int err) 
static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,

				       dm_oblock_t oblock, dm_cblock_t cblock)

{

	struct per_bio_data *pb = get_per_bio_data(bio);

	struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);



	pb->cache = cache;

	pb->cblock = cblock;

	pb->saved_bi_end_io = bio->bi_end_io;

	dm_bio_record(&pb->bio_details, bio);

	bio->bi_end_io = writethrough_endio;



	remap_to_origin_clear_discard(pb->cache, bio, oblock);
@@ -1035,7 +1056,8 @@ static void defer_bio(struct cache *cache, struct bio *bio) 


static void process_flush_bio(struct cache *cache, struct bio *bio)

{

	struct per_bio_data *pb = get_per_bio_data(bio);

	size_t pb_data_size = get_per_bio_data_size(cache);

	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);



	BUG_ON(bio->bi_size);

	if (!pb->req_nr)
@@ -1107,7 +1129,8 @@ static void process_bio(struct cache *cache, struct prealloc *structs, 
	dm_oblock_t block = get_bio_block(cache, bio);

	struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;

	struct policy_result lookup_result;

	struct per_bio_data *pb = get_per_bio_data(bio);

	size_t pb_data_size = get_per_bio_data_size(cache);

	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	bool discarded_block = is_discarded_oblock(cache, block);

	bool can_migrate = discarded_block || spare_migration_bandwidth(cache);
@@ -1881,7 +1904,6 @@ static int cache_create(struct cache_args *ca, struct cache **result) 


	cache->ti = ca->ti;

	ti->private = cache;

	ti->per_bio_data_size = sizeof(struct per_bio_data);

	ti->num_flush_bios = 2;

	ti->flush_supported = true;
@@ -1890,6 +1912,7 @@ static int cache_create(struct cache_args *ca, struct cache **result) 
	ti->discard_zeroes_data_unsupported = true;



	memcpy(&cache->features, &ca->features, sizeof(cache->features));

	ti->per_bio_data_size = get_per_bio_data_size(cache);



	cache->callbacks.congested_fn = cache_is_congested;

	dm_table_add_target_callbacks(ti->table, &cache->callbacks);
@@ -2092,6 +2115,7 @@ static int cache_map(struct dm_target *ti, struct bio *bio) 


	int r;

	dm_oblock_t block = get_bio_block(cache, bio);

	size_t pb_data_size = get_per_bio_data_size(cache);

	bool can_migrate = false;

	bool discarded_block;

	struct dm_bio_prison_cell *cell;
@@ -2108,7 +2132,7 @@ static int cache_map(struct dm_target *ti, struct bio *bio) 
		return DM_MAPIO_REMAPPED;

	}



	pb = init_per_bio_data(bio);

	pb = init_per_bio_data(bio, pb_data_size);



	if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) {

		defer_bio(cache, bio);
@@ -2193,7 +2217,8 @@ static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) 
{

	struct cache *cache = ti->private;

	unsigned long flags;

	struct per_bio_data *pb = get_per_bio_data(bio);

	size_t pb_data_size = get_per_bio_data_size(cache);

	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);



	if (pb->tick) {

		policy_tick(cache->policy);