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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>
hifive-unleashed-5.1
Joe Thornber 2017-03-31 10:09:45 -04:00 committed by Mike Snitzer
parent 7b81ef8b14
commit 449b668ce0
1 changed files with 6 additions and 0 deletions
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6
drivers/md/dm-cache-target.c
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@ -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;