dm cache: set/clear the cache core's dirty_bitset when loading mappings
When loading metadata make sure to set/clear the dirty bits in the cache
core's dirty_bitset as well as the policy.
Otherwise the cache core is unaware that any blocks were dirty when the
cache was last shutdown. A very serious side-effect being that the
cleaner policy would therefore never be tasked with writing back dirty
data from a cache that was in writeback mode (e.g. when switching from
smq policy to cleaner policy when decommissioning a writeback cache).
This fixes a serious data corruption bug associated with writeback mode.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index b7de289..6e747fc 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2960,6 +2960,12 @@ static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
int r;
struct cache *cache = context;
+ if (dirty) {
+ set_bit(from_cblock(cblock), cache->dirty_bitset);
+ atomic_inc(&cache->nr_dirty);
+ } else
+ clear_bit(from_cblock(cblock), cache->dirty_bitset);
+
r = policy_load_mapping(cache->policy, oblock, cblock, dirty, hint, hint_valid);
if (r)
return r;