dm cache: dirty flag was mistakenly being cleared when promoting via overwrite

If the incoming bio is a WRITE and completely covers a block then we
don't bother to do any copying for a promotion operation.  Once this is
done the cache block and origin block will be different, so we need to
set it to 'dirty'.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index ef842fe..1a090de 100644 (file)
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -988,10 +988,14 @@ static void migration_success_post_commit(struct dm_cache_migration *mg)
                }
 
        } else {
-               clear_dirty(cache, mg->new_oblock, mg->cblock);
-               if (mg->requeue_holder)
+               if (mg->requeue_holder) {
+                       clear_dirty(cache, mg->new_oblock, mg->cblock);
                        cell_defer(cache, mg->new_ocell, true);
-               else {
+               } else {
+                       /*
+                        * The block was promoted via an overwrite, so it's dirty.
+                        */
+                       set_dirty(cache, mg->new_oblock, mg->cblock);
                        bio_endio(mg->new_ocell->holder, 0);
                        cell_defer(cache, mg->new_ocell, false);
                }