dm cache metadata: add "metadata2" feature

If "metadata2" is provided as a table argument when creating/loading a
cache target a more compact metadata format, with separate dirty bits,
is used.  "metadata2" improves speed of shutting down a cache target.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/md/dm-cache-metadata.h b/drivers/md/dm-cache-metadata.h
index 8528744195e5..4f07c08cf107 100644
--- a/drivers/md/dm-cache-metadata.h
+++ b/drivers/md/dm-cache-metadata.h
@@ -45,18 +45,20 @@
  * As these various flags are defined they should be added to the
  * following masks.
  */
+
 #define DM_CACHE_FEATURE_COMPAT_SUPP	  0UL
 #define DM_CACHE_FEATURE_COMPAT_RO_SUPP	  0UL
 #define DM_CACHE_FEATURE_INCOMPAT_SUPP	  0UL
 
 /*
- * Reopens or creates a new, empty metadata volume.
- * Returns an ERR_PTR on failure.
+ * Reopens or creates a new, empty metadata volume.  Returns an ERR_PTR on
+ * failure.  If reopening then features must match.
  */
 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
 						 sector_t data_block_size,
 						 bool may_format_device,
-						 size_t policy_hint_size);
+						 size_t policy_hint_size,
+						 unsigned metadata_version);
 
 void dm_cache_metadata_close(struct dm_cache_metadata *cmd);
 
@@ -91,7 +93,8 @@ int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
 			   load_mapping_fn fn,
 			   void *context);
 
-int dm_cache_set_dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty);
+int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
+			    unsigned nr_bits, unsigned long *bits);
 
 struct dm_cache_statistics {
 	uint32_t read_hits;