| From feb7695fe9fb83084aa29de0094774f4c9d4c9fc Mon Sep 17 00:00:00 2001 |
| From: Mike Snitzer <snitzer@redhat.com> |
| Date: Tue, 20 Jun 2017 19:14:30 -0400 |
| Subject: dm io: fix duplicate bio completion due to missing ref count |
| |
| From: Mike Snitzer <snitzer@redhat.com> |
| |
| commit feb7695fe9fb83084aa29de0094774f4c9d4c9fc upstream. |
| |
| 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 <yizhan@redhat.com> |
| Signed-off-by: Mike Snitzer <snitzer@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/md/dm-io.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/drivers/md/dm-io.c |
| +++ b/drivers/md/dm-io.c |
| @@ -299,6 +299,7 @@ static void do_region(int rw, unsigned r |
| 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; |
| } |
