Don't set I/O Scheduler for Partitions

ZFS should only change the i/o scheduler for a disk when it has
ownership of the whole disk.  This is basically the same logic as
adjusting the write cache behavior on a disk.  This change updates
the vdev disk code to skip partitions when setting the i/o scheduler.

Closes #152

1 files changed, 4 insertions, 0 deletions

diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c
index 69bc53b4b..ec627a9c4 100644
--- a/module/zfs/vdev_disk.c
+++ b/module/zfs/vdev_disk.c
@@ -131,6 +131,10 @@ vdev_elevator_switch(vdev_t *v, char *elevator)
 	char *envp[] = { NULL };
 	int count = 0, error;
 
+	/* Skip devices which are not whole disks (partitions) */
+	if (!v->vdev_wholedisk)
+		return (0);
+
 	/* Skip devices without schedulers (loop, ram, dm, etc) */
 	if (!q->elevator || !blk_queue_stackable(q))
 		return (0);