From: Mike Snitzer Date: Tue, 20 Jun 2017 23:14:30 +0000 (-0400) Subject: dm io: fix duplicate bio completion due to missing ref count X-Git-Tag: v4.1.51~51 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f3c22cc3eaf1534d0aa8ec2ed8d3ddde413930ae;p=thirdparty%2Fkernel%2Fstable.git dm io: fix duplicate bio completion due to missing ref count [ Upstream commit feb7695fe9fb83084aa29de0094774f4c9d4c9fc ] If only a subset of the devices associated with multiple regions support a given special operation (eg. DISCARD) then the dec_count() that is used to set error for the region must increment the io->count. Otherwise, when the dec_count() is called it can cause the dm-io caller's bio to be completed multiple times. As was reported against the dm-mirror target that had mirror legs with a mix of discard capabilities. Bug: https://bugzilla.kernel.org/show_bug.cgi?id=196077 Reported-by: Zhang Yi Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin --- diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c index 74adcd2c967ec..01d7b5785b8e5 100644 --- a/drivers/md/dm-io.c +++ b/drivers/md/dm-io.c @@ -299,6 +299,7 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where, else if (rw & REQ_WRITE_SAME) special_cmd_max_sectors = q->limits.max_write_same_sectors; if ((rw & (REQ_DISCARD | REQ_WRITE_SAME)) && special_cmd_max_sectors == 0) { + atomic_inc(&io->count); dec_count(io, region, -EOPNOTSUPP); return; }