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>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/md/dm-cache-policy-cleaner.c b/drivers/md/dm-cache-policy-cleaner.c
index cc05d70b3cb8..b04d1f904d07 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 *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;
 }