md/raid5-cache: exclude reclaiming stripes in reclaim check

stripes which are being reclaimed are still accounted into cached
stripes. The reclaim takes time. r5c_do_reclaim isn't aware of the
stripes and does unnecessary stripe reclaim. In practice, I saw one
stripe is reclaimed one time. This will cause bad IO pattern. Fixing
this by excluding the reclaing stripes in the check.

Cc: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index b0d1345c832c..e2fa88fc6a1b 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6838,6 +6838,8 @@ static struct r5conf *setup_conf(struct mddev *mddev)
         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
         atomic_set(&conf->r5c_cached_partial_stripes, 0);
         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
+        atomic_set(&conf->r5c_flushing_full_stripes, 0);
+        atomic_set(&conf->r5c_flushing_partial_stripes, 0);
 
         conf->level = mddev->new_level;
         conf->chunk_sectors = mddev->new_chunk_sectors;