rbd: add 'minor' sysfs rbd device attribute

Introduce /sys/bus/rbd/devices/<id>/minor sysfs attribute for exporting
rbd whole disk minor numbers.  This is a step towards single-major
device number allocation scheme, but also a good thing on its own.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-rbd b/Documentation/ABI/testing/sysfs-bus-rbd
index 0a306476424e..17b119c692da 100644
--- a/Documentation/ABI/testing/sysfs-bus-rbd
+++ b/Documentation/ABI/testing/sysfs-bus-rbd
@@ -33,6 +33,10 @@ major
 
         The block device major number.
 
+minor
+
+        The block device minor number.  (December 2013, since 3.14.)
+
 name
 
         The name of the rbd image.