From: Joe Thornber ejt@redhat.com
commit 1e4ab7b4c881cf26c1c72b3f56519e03475486fb upstream.
When using the cleaner policy to decommission the cache, there is never any writeback started from the cache as it is constantly delayed due to normal I/O keeping the device busy. Meaning @idle=false was always being passed to clean_target_met()
Fix this by adding a specific 'cleaner' flag that is set when the cleaner policy is configured. This flag serves to always allow the cleaner's writeback work to be queued until the cache is decommissioned (even if the cache isn't idle).
Reported-by: David Jeffery djeffery@redhat.com Fixes: b29d4986d0da ("dm cache: significant rework to leverage dm-bio-prison-v2") Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber ejt@redhat.com Signed-off-by: Mike Snitzer snitzer@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm-cache-policy-smq.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-)
--- a/drivers/md/dm-cache-policy-smq.c +++ b/drivers/md/dm-cache-policy-smq.c @@ -855,7 +855,13 @@ struct smq_policy {
struct background_tracker *bg_work;
- bool migrations_allowed; + bool migrations_allowed:1; + + /* + * If this is set the policy will try and clean the whole cache + * even if the device is not idle. + */ + bool cleaner:1; };
/*----------------------------------------------------------------*/ @@ -1136,7 +1142,7 @@ static bool clean_target_met(struct smq_ * Cache entries may not be populated. So we cannot rely on the * size of the clean queue. */ - if (idle) { + if (idle || mq->cleaner) { /* * We'd like to clean everything. */ @@ -1719,11 +1725,9 @@ static void calc_hotspot_params(sector_t *hotspot_block_size /= 2u; }
-static struct dm_cache_policy *__smq_create(dm_cblock_t cache_size, - sector_t origin_size, - sector_t cache_block_size, - bool mimic_mq, - bool migrations_allowed) +static struct dm_cache_policy * +__smq_create(dm_cblock_t cache_size, sector_t origin_size, sector_t cache_block_size, + bool mimic_mq, bool migrations_allowed, bool cleaner) { unsigned int i; unsigned int nr_sentinels_per_queue = 2u * NR_CACHE_LEVELS; @@ -1810,6 +1814,7 @@ static struct dm_cache_policy *__smq_cre goto bad_btracker;
mq->migrations_allowed = migrations_allowed; + mq->cleaner = cleaner;
return &mq->policy;
@@ -1833,21 +1838,24 @@ static struct dm_cache_policy *smq_creat sector_t origin_size, sector_t cache_block_size) { - return __smq_create(cache_size, origin_size, cache_block_size, false, true); + return __smq_create(cache_size, origin_size, cache_block_size, + false, true, false); }
static struct dm_cache_policy *mq_create(dm_cblock_t cache_size, sector_t origin_size, sector_t cache_block_size) { - return __smq_create(cache_size, origin_size, cache_block_size, true, true); + return __smq_create(cache_size, origin_size, cache_block_size, + true, true, false); }
static struct dm_cache_policy *cleaner_create(dm_cblock_t cache_size, sector_t origin_size, sector_t cache_block_size) { - return __smq_create(cache_size, origin_size, cache_block_size, false, false); + return __smq_create(cache_size, origin_size, cache_block_size, + false, false, true); }
/*----------------------------------------------------------------*/