1 files changed, 13 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index c1eb41cb9876..2b5d56127fce 100644
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -206,3 +206,16 @@ Description:
                 when a discarded area is read the discard_zeroes_data
                 parameter will be set to one. Otherwise it will be 0 and
                 the result of reading a discarded area is undefined.
+What:           /sys/block/<disk>/alias
+Date:           Aug 2011
+Contact:        Nao Nishijima <nao.nishijima.xt@hitachi.com>
+Description:
+                A raw device name of a disk does not always point a same disk
+                each boot-up time. Therefore, users have to use persistent
+                device names, which udev creates when the kernel finds a disk,
+                instead of raw device name. However, kernel doesn't show those
+                persistent names on its messages (e.g. dmesg).
+                This file can store an alias of the disk and it would be
+                appeared in kernel messages if it is set. A disk can have an
+                alias which length is up to 255bytes. Users can use alphabets,
+                numbers, "-" and "_" in alias name. This file is writeonce.