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: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 1bb9180..74213d1 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -83,6 +83,8 @@
__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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
__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 @@
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)
diff --git a/drivers/md/dm-cache-policy-cleaner.c b/drivers/md/dm-cache-policy-cleaner.c
index cc05d70..b04d1f9 100644
--- a/drivers/md/dm-cache-policy-cleaner.c
+++ b/drivers/md/dm-cache-policy-cleaner.c
@@ -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_type wb_policy_type = {
.name = "cleaner",
+ .version = {1, 0, 0},
.hint_size = 0,
.owner = THIS_MODULE,
.create = wb_create
@@ -446,7 +446,10 @@
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;
}
diff --git a/drivers/md/dm-cache-policy-internal.h b/drivers/md/dm-cache-policy-internal.h
index 52a75be..0928abd 100644
--- a/drivers/md/dm-cache-policy-internal.h
+++ b/drivers/md/dm-cache-policy-internal.h
@@ -117,6 +117,8 @@
*/
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);
/*----------------------------------------------------------------*/
diff --git a/drivers/md/dm-cache-policy-mq.c b/drivers/md/dm-cache-policy-mq.c
index 9641532..dc112a7 100644
--- a/drivers/md/dm-cache-policy-mq.c
+++ b/drivers/md/dm-cache-policy-mq.c
@@ -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_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 default_policy_type = {
.name = "default",
+ .version = {1, 0, 0},
.hint_size = 4,
.owner = THIS_MODULE,
.create = mq_create
@@ -1164,7 +1165,10 @@
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;
}
diff --git a/drivers/md/dm-cache-policy.c b/drivers/md/dm-cache-policy.c
index 2cbf5fd..21c03c5 100644
--- a/drivers/md/dm-cache-policy.c
+++ b/drivers/md/dm-cache-policy.c
@@ -150,6 +150,14 @@
}
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;
diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h
index f0f51b2..558bdfd 100644
--- a/drivers/md/dm-cache-policy.h
+++ b/drivers/md/dm-cache-policy.h
@@ -196,6 +196,7 @@
* We maintain a little register of the different policy types.
*/
#define CACHE_POLICY_NAME_SIZE 16
+#define CACHE_POLICY_VERSION_SIZE 3
struct dm_cache_policy_type {
/* For use by the register code only. */
@@ -206,6 +207,7 @@
* what gets passed on the target line to select your policy.
*/
char name[CACHE_POLICY_NAME_SIZE];
+ unsigned version[CACHE_POLICY_VERSION_SIZE];
/*
* Policies may store a hint for each each cache block.