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Commit 4e7f506f authored by Mike Snitzer's avatar Mike Snitzer Committed by Alasdair G Kergon
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dm cache: policy change version from string to integer set 



Separate dm cache policy version string into 3 unsigned numbers
corresponding to major, minor and patchlevel and store them at the end
of the on-disk metadata so we know which version of the policy generated
the hints in case a future version wants to use them differently.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent e2e74d61

drivers/md/dm-cache-metadata.c

+13 −2
Original line number Diff line number Diff line
@@ -83,6 +83,8 @@ struct cache_disk_superblock { 
	__le32 read_misses;

	__le32 write_hits;

	__le32 write_misses;



	__le32 policy_version[CACHE_POLICY_VERSION_SIZE];

} __packed;



struct dm_cache_metadata {
@@ -109,6 +111,7 @@ struct dm_cache_metadata { 
	bool clean_when_opened:1;



	char policy_name[CACHE_POLICY_NAME_SIZE];

	unsigned policy_version[CACHE_POLICY_VERSION_SIZE];

	size_t policy_hint_size;

	struct dm_cache_statistics stats;

};
@@ -268,7 +271,8 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd) 
	memset(disk_super->uuid, 0, sizeof(disk_super->uuid));

	disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);

	disk_super->version = cpu_to_le32(CACHE_VERSION);

	memset(disk_super->policy_name, 0, CACHE_POLICY_NAME_SIZE);

	memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));

	memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));

	disk_super->policy_hint_size = 0;



	r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
@@ -284,7 +288,6 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd) 
	disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);

	disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);

	disk_super->cache_blocks = cpu_to_le32(0);

	memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));



	disk_super->read_hits = cpu_to_le32(0);

	disk_super->read_misses = cpu_to_le32(0);
@@ -478,6 +481,9 @@ static void read_superblock_fields(struct dm_cache_metadata *cmd, 
	cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);

	cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));

	strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));

	cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);

	cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);

	cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);

	cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);



	cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
@@ -572,6 +578,9 @@ static int __commit_transaction(struct dm_cache_metadata *cmd, 
	disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));

	disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));

	strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));

	disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);

	disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);

	disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);



	disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);

	disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
@@ -1070,6 +1079,7 @@ static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *po 
	__le32 value;

	size_t hint_size;

	const char *policy_name = dm_cache_policy_get_name(policy);

	const unsigned *policy_version = dm_cache_policy_get_version(policy);



	if (!policy_name[0] ||

	    (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
@@ -1077,6 +1087,7 @@ static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *po 


	if (strcmp(cmd->policy_name, policy_name)) {

		strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));

		memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));



		hint_size = dm_cache_policy_get_hint_size(policy);

		if (!hint_size)

drivers/md/dm-cache-policy-cleaner.c

+5 −2
Original line number Diff line number Diff line
@@ -17,7 +17,6 @@ 
/*----------------------------------------------------------------*/



#define DM_MSG_PREFIX "cache cleaner"

#define CLEANER_VERSION "1.0.0"



/* Cache entry struct. */

struct wb_cache_entry {
@@ -434,6 +433,7 @@ static struct dm_cache_policy *wb_create(dm_cblock_t cache_size, 


static struct dm_cache_policy_type wb_policy_type = {

	.name = "cleaner",

	.version = {1, 0, 0},

	.hint_size = 0,

	.owner = THIS_MODULE,

	.create = wb_create
@@ -446,7 +446,10 @@ static int __init wb_init(void) 
	if (r < 0)

		DMERR("register failed %d", r);

	else

		DMINFO("version " CLEANER_VERSION " loaded");

		DMINFO("version %u.%u.%u loaded",

		       wb_policy_type.version[0],

		       wb_policy_type.version[1],

		       wb_policy_type.version[2]);



	return r;

}

drivers/md/dm-cache-policy-internal.h

+2 −0
Original line number Diff line number Diff line
@@ -117,6 +117,8 @@ void dm_cache_policy_destroy(struct dm_cache_policy *p); 
 */

const char *dm_cache_policy_get_name(struct dm_cache_policy *p);



const unsigned *dm_cache_policy_get_version(struct dm_cache_policy *p);



size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p);



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

drivers/md/dm-cache-policy-mq.c

+6 −2
Original line number Diff line number Diff line
@@ -14,7 +14,6 @@ 
#include <linux/vmalloc.h>



#define DM_MSG_PREFIX "cache-policy-mq"

#define MQ_VERSION	"1.0.0"



static struct kmem_cache *mq_entry_cache;
@@ -1133,6 +1132,7 @@ static struct dm_cache_policy *mq_create(dm_cblock_t cache_size, 


static struct dm_cache_policy_type mq_policy_type = {

	.name = "mq",

	.version = {1, 0, 0},

	.hint_size = 4,

	.owner = THIS_MODULE,

	.create = mq_create
@@ -1140,6 +1140,7 @@ static struct dm_cache_policy_type mq_policy_type = { 


static struct dm_cache_policy_type default_policy_type = {

	.name = "default",

	.version = {1, 0, 0},

	.hint_size = 4,

	.owner = THIS_MODULE,

	.create = mq_create
@@ -1164,7 +1165,10 @@ static int __init mq_init(void) 


	r = dm_cache_policy_register(&default_policy_type);

	if (!r) {

		DMINFO("version " MQ_VERSION " loaded");

		DMINFO("version %u.%u.%u loaded",

		       mq_policy_type.version[0],

		       mq_policy_type.version[1],

		       mq_policy_type.version[2]);

		return 0;

	}

drivers/md/dm-cache-policy.c

+8 −0
Original line number Diff line number Diff line
@@ -150,6 +150,14 @@ const char *dm_cache_policy_get_name(struct dm_cache_policy *p) 
}

EXPORT_SYMBOL_GPL(dm_cache_policy_get_name);



const unsigned *dm_cache_policy_get_version(struct dm_cache_policy *p)

{

	struct dm_cache_policy_type *t = p->private;



	return t->version;

}

EXPORT_SYMBOL_GPL(dm_cache_policy_get_version);



size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p)

{

	struct dm_cache_policy_type *t = p->private;