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authorJan Kara <jack@suse.cz>2017-05-31 10:44:32 +0300
committerMike Snitzer <snitzer@redhat.com>2017-05-31 17:50:23 +0300
commitff0361b34ac63ef80c785c32d62e0e9d89a2cf89 (patch)
treedf6bce75c164f09c052d464bfbf4d2ba7f44797e /drivers/md/dm.c
parent8c1e2162f27b319da913683143c0c6c09b083ebb (diff)
downloadlinux-ff0361b34ac63ef80c785c32d62e0e9d89a2cf89.tar.xz
dm: make flush bios explicitly sync
Commit b685d3d65ac7 ("block: treat REQ_FUA and REQ_PREFLUSH as synchronous") removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...} definitions. generic_make_request_checks() however strips REQ_FUA and REQ_PREFLUSH flags from a bio when the storage doesn't report volatile write cache and thus write effectively becomes asynchronous which can lead to performance regressions. Fix the problem by making sure all bios which are synchronous are properly marked with REQ_SYNC. Fixes: b685d3d65ac7 ("block: treat REQ_FUA and REQ_PREFLUSH as synchronous") Cc: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6ef9500226c0..37ccd73c79ec 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1657,7 +1657,7 @@ static struct mapped_device *alloc_dev(int minor)
bio_init(&md->flush_bio, NULL, 0);
md->flush_bio.bi_bdev = md->bdev;
- md->flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
+ md->flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
dm_stats_init(&md->stats);