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authorMike Snitzer <snitzer@redhat.com>2017-06-20 19:14:30 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-11 16:12:19 +0100
commit91e5f485ec89c4b49fdde28b18d959535d500b3d (patch)
treedd8e1969f74955e69882a5f13f90a86e32240986
parent11523616183342c775d1f88fada910fc188239ce (diff)
dm io: fix duplicate bio completion due to missing ref count
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>
-rw-r--r--drivers/md/dm-io.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 74adcd2c967e..01d7b5785b8e 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;
}