[PATCH] device-mapper multipath: Barriers not supported

dm multipath will report barriers as not supported with this patch.

Signed-off-by: Lars Marowsky-Bree <lmb@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 8 insertions, 2 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 0c1b8520ef86..84cdb700a247 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -765,6 +765,9 @@ static int multipath_map(struct dm_target *ti, struct bio *bio,
         struct mpath_io *mpio;
         struct multipath *m = (struct multipath *) ti->private;
 
+        if (bio_barrier(bio))
+                return -EOPNOTSUPP;
+
         mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
         dm_bio_record(&mpio->details, bio);
 
@@ -988,6 +991,9 @@ static int do_end_io(struct multipath *m, struct bio *bio,
         if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
                 return error;
 
+        if (error == -EOPNOTSUPP)
+                return error;
+
         spin_lock(&m->lock);
         if (!m->nr_valid_paths) {
                 if (!m->queue_if_no_path || m->suspended) {
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 7e691ab9a748..594d1f6b4789 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -777,7 +777,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
 
         /* Full snapshots are not usable */
         if (!s->valid)
-                return -1;
+                return -EIO;
 
         /*
          * Write to snapshot - higher level takes care of RW/RO
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f6b03957efc7..5d40555b42ba 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -384,7 +384,7 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
                 /* error the io and bail out */
                 struct dm_io *io = tio->io;
                 free_tio(tio->io->md, tio);
-                dec_pending(io, -EIO);
+                dec_pending(io, r);
                 bio_put(clone);
         }
 }