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authorJoe Thornber <ejt@redhat.com>2012-07-27 15:08:06 +0100
committerAlasdair G Kergon <agk@redhat.com>2012-07-27 15:08:06 +0100
commit600497013687516153cb82637acfe56f7eb9308a (patch)
treed44382be55c68208ba7344dfaca8ade10e87c0d5 /drivers/md/dm-thin.c
parent905386f82d08f66726912f303f3e6605248c60a3 (diff)
downloadop-kernel-dev-600497013687516153cb82637acfe56f7eb9308a.zip
op-kernel-dev-600497013687516153cb82637acfe56f7eb9308a.tar.gz
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: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-thin.c')
-rw-r--r--drivers/md/dm-thin.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 423df92..7510cb3 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -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;
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