xen: document backend sysfs files
Add ABI documentation for the /sys/bus/xen-backend sysfs files,
including those specific to blkback devices.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/Documentation/ABI/stable/sysfs-bus-xen-backend b/Documentation/ABI/stable/sysfs-bus-xen-backend
new file mode 100644
index 0000000..3d5951c
--- /dev/null
+++ b/Documentation/ABI/stable/sysfs-bus-xen-backend
@@ -0,0 +1,75 @@
+What: /sys/bus/xen-backend/devices/*/devtype
+Date: Feb 2009
+KernelVersion: 2.6.38
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ The type of the device. e.g., one of: 'vbd' (block),
+ 'vif' (network), or 'vfb' (framebuffer).
+
+What: /sys/bus/xen-backend/devices/*/nodename
+Date: Feb 2009
+KernelVersion: 2.6.38
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ XenStore node (under /local/domain/NNN/) for this
+ backend device.
+
+What: /sys/bus/xen-backend/devices/vbd-*/physical_device
+Date: April 2011
+KernelVersion: 3.0
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ The major:minor number (in hexidecimal) of the
+ physical device providing the storage for this backend
+ block device.
+
+What: /sys/bus/xen-backend/devices/vbd-*/mode
+Date: April 2011
+KernelVersion: 3.0
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ Whether the block device is read-only ('r') or
+ read-write ('w').
+
+What: /sys/bus/xen-backend/devices/vbd-*/statistics/f_req
+Date: April 2011
+KernelVersion: 3.0
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ Number of flush requests from the frontend.
+
+What: /sys/bus/xen-backend/devices/vbd-*/statistics/oo_req
+Date: April 2011
+KernelVersion: 3.0
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ Number of requests delayed because the backend was too
+ busy processing previous requests.
+
+What: /sys/bus/xen-backend/devices/vbd-*/statistics/rd_req
+Date: April 2011
+KernelVersion: 3.0
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ Number of read requests from the frontend.
+
+What: /sys/bus/xen-backend/devices/vbd-*/statistics/rd_sect
+Date: April 2011
+KernelVersion: 3.0
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ Number of sectors read by the frontend.
+
+What: /sys/bus/xen-backend/devices/vbd-*/statistics/wr_req
+Date: April 2011
+KernelVersion: 3.0
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ Number of write requests from the frontend.
+
+What: /sys/bus/xen-backend/devices/vbd-*/statistics/wr_sect
+Date: April 2011
+KernelVersion: 3.0
+Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+ Number of sectors written by the frontend.
