MD: add a new disk role to present write journal device
Next patches will use a disk as raid5/6 journaling. We need a new disk
role to present the journal device and add MD_FEATURE_JOURNAL to
feature_map for backward compability.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 2ea0035..88dc631 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -172,6 +172,11 @@
* This device is seen locally but not
* by the whole cluster
*/
+ Journal, /* This device is used as journal for
+ * raid-5/6.
+ * Usually, this device should be faster
+ * than other devices in the array
+ */
};
#define BB_LEN_MASK (0x00000000000001FFULL)