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| author | Mike Snitzer <snitzer@redhat.com> | 2013-03-20 17:21:27 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2013-03-20 17:21:27 +0000 |
| commit | 4e7f506f6429636115e2f58f9f97089acc62524a (patch) | |
| tree | 8758ebd6ee210ec303b661df775f31b3e9f45dd9 /drivers/md/dm-cache-metadata.c | |
| parent | e2e74d617eadc15f601983270c4f4a6935c5a943 (diff) | |
| download | lwn-4e7f506f6429636115e2f58f9f97089acc62524a.tar.gz lwn-4e7f506f6429636115e2f58f9f97089acc62524a.zip | |
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>
Diffstat (limited to 'drivers/md/dm-cache-metadata.c')
| -rw-r--r-- | drivers/md/dm-cache-metadata.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c index 1bb91802b22a..74213d1f1db5 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -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) |