From feb7695fe9fb83084aa29de0094774f4c9d4c9fc Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 20 Jun 2017 19:14:30 -0400 Subject: [PATCH] dm io: fix duplicate bio completion due to missing ref count 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 --- drivers/md/dm-io.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c index 3702e502466d..8d5ca30f6551 100644 --- a/drivers/md/dm-io.c +++ b/drivers/md/dm-io.c @@ -317,8 +317,8 @@ static void do_region(int op, int op_flags, unsigned region, else if (op == REQ_OP_WRITE_SAME) special_cmd_max_sectors = q->limits.max_write_same_sectors; if ((op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES || - op == REQ_OP_WRITE_SAME) && - special_cmd_max_sectors == 0) { + op == REQ_OP_WRITE_SAME) && special_cmd_max_sectors == 0) { + atomic_inc(&io->count); dec_count(io, region, -EOPNOTSUPP); return; }