[PATCH 3.16.y-ckt 061/216] dm cache: dirty flag was mistakenly being cleared when promoting via overwrite

Luis Henriques
2015-01-12T18:23:23Z

From: Joe Thornber <ejt@redhat.com>

commit 1e32134a5a404e80bfb47fad8a94e9bbfcbdacc5 upstream.

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>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
drivers/md/dm-cache-target.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index e5bb12810ccc..e5308b8b4043 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -929,10 +929,14 @@ 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);
}
--
2.1.4