[PATCH] md: expose device slot information via sysfs

This the role that a device has in an array can be viewed and set.

Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/md.txt b/Documentation/md.txt
index 69f742dee00f..d525fffc873b 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -236,6 +236,14 @@ Each directory contains:
         providing an ongoing count for arrays with metadata managed by
         userspace.
 
+      slot
+        This gives the role that the device has in the array.  It will
+        either be 'none' if the device is not active in the array
+        (i.e. is a spare or has failed) or an integer less than the
+        'raid_disks' number for the array indicating which possition
+        it currently fills.  This can only be set while assembling an
+        array.  A device for which this is set is assumed to be working.
+
 
 An active md device will also contain and entry for each active device
 in the array.  These are named