Commit 60049701 authored by Joe Thornber's avatar Joe Thornber Committed by Alasdair G Kergon
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dm thin: avoid unnecessarily breaking sharing for flushes 



There's no need to break sharing, triggering a copy, for a write that has no
data (i.e. a flush).

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 905386f8

drivers/md/dm-thin.c

+1 −1
Original line number Diff line number Diff line
@@ -1315,7 +1315,7 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio, 
	if (bio_detain(pool->prison, &key, bio, &cell))

		return;



	if (bio_data_dir(bio) == WRITE)

	if (bio_data_dir(bio) == WRITE && bio->bi_size)

		break_sharing(tc, bio, block, &key, lookup_result, cell);

	else {

		struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;