From: Alasdair G Kergon dm multipath will report barriers as not supported with this patch. Signed-off-by: Lars Marowsky-Bree Signed-off-by: Alasdair G Kergon Signed-off-by: Andrew Morton --- drivers/md/dm-mpath.c | 6 ++++++ drivers/md/dm-snap.c | 2 +- drivers/md/dm.c | 2 +- 3 files changed, 8 insertions(+), 2 deletions(-) diff -puN drivers/md/dm.c~device-mapper-multipath-barriers-not-supported drivers/md/dm.c --- 25/drivers/md/dm.c~device-mapper-multipath-barriers-not-supported Fri Jul 8 16:45:27 2005 +++ 25-akpm/drivers/md/dm.c Fri Jul 8 16:45:27 2005 @@ -384,7 +384,7 @@ static void __map_bio(struct dm_target * /* 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); } } diff -puN drivers/md/dm-mpath.c~device-mapper-multipath-barriers-not-supported drivers/md/dm-mpath.c --- 25/drivers/md/dm-mpath.c~device-mapper-multipath-barriers-not-supported Fri Jul 8 16:45:27 2005 +++ 25-akpm/drivers/md/dm-mpath.c Fri Jul 8 16:45:27 2005 @@ -765,6 +765,9 @@ static int multipath_map(struct dm_targe 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 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 -puN drivers/md/dm-snap.c~device-mapper-multipath-barriers-not-supported drivers/md/dm-snap.c --- 25/drivers/md/dm-snap.c~device-mapper-multipath-barriers-not-supported Fri Jul 8 16:45:27 2005 +++ 25-akpm/drivers/md/dm-snap.c Fri Jul 8 16:45:27 2005 @@ -777,7 +777,7 @@ static int snapshot_map(struct dm_target /* Full snapshots are not usable */ if (!s->valid) - return -1; + return -EIO; /* * Write to snapshot - higher level takes care of RW/RO _