Set elevator for DM devices despite vdev_wholedisk

[zfs.git] / module / zfs / vdev_disk.c

diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c
index 8df43d1..3f9b624 100644 (file)
--- a/module/zfs/vdev_disk.c
+++ b/module/zfs/vdev_disk.c
@@ -121,8 +121,15 @@ vdev_elevator_switch(vdev_t *v, char *elevator)
        char *device = bdev->bd_disk->disk_name;
        int error;
 
-       /* Skip devices which are not whole disks (partitions) */
-       if (!v->vdev_wholedisk)
+       /*
+        * Skip devices which are not whole disks (partitions).
+        * Device-mapper devices are excepted since they may be whole
+        * disks despite the vdev_wholedisk flag, in which case we can
+        * and should switch the elevator. If the device-mapper device
+        * does not have an elevator (i.e. dm-raid, dm-crypt, etc.) the
+        * "Skip devices without schedulers" check below will fail.
+        */
+       if (!v->vdev_wholedisk && strncmp(device, "dm-", 3) != 0)
                return (0);
 
        /* Skip devices without schedulers (loop, ram, dm, etc) */