[Qemu-devel] qemu-img: document 'info --backing-chain

[Kashyap Chamarthy]

>From a6233277e17338f571dda27cd9192d764f824b18 Mon Sep 17 00:00:00 2001
From: Kashyap Chamarthy <address@hidden>
Date: Sun, 14 Oct 2012 09:51:18 +0530
Subject: [PATCH v2] qemu-img: document 'info --backing-chain'

Signed-off-by: Kashyap Chamarthy <address@hidden>
---
 qemu-img-cmds.hx |  4 ++--
 qemu-img.texi    | 19 ++++++++++++++++++-
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 
0ef82e9ac7a89d607e1f2c8e38461cee5b438dba..a18136302d2ca7a7540672f1b9ef89603e89edc0
 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -34,9 +34,9 @@ STEXI
 ETEXI
 
 DEF("info", img_info,
-    "info [-f fmt] [--output=ofmt] filename")
+    "info [-f fmt] [--output=ofmt] [--backing-chain] filename")
 STEXI
address@hidden info [-f @var{fmt}] address@hidden @var{filename}
address@hidden info [-f @var{fmt}] address@hidden [--backing-chain] 
@var{filename}
 ETEXI
 
 DEF("snapshot", img_snapshot,
diff --git a/qemu-img.texi b/qemu-img.texi
index 
8b05f2c42801a2535ab4390b47bc415eb880625a..ffd334dc7b049c50474be88376acd5267ad96c3c
 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -28,6 +28,10 @@ Command parameters:
 is the disk image format. It is guessed automatically in most cases. See below
 for a description of the supported disk formats.
 
address@hidden --backing-chain 
+will enumerate information about backing files in a disk image chain. Refer
+below for further description.
+
 @item size
 is the disk image size in bytes. Optional suffixes @code{k} or @code{K}
 (kilobyte, 1024) @code{M} (megabyte, 1024k) and @code{G} (gigabyte, 1024M)
@@ -129,7 +133,7 @@ created as a copy on write image of the specified base 
image; the
 @var{backing_file} should have the same content as the input's base image,
 however the path, image format, etc may differ.
 
address@hidden info [-f @var{fmt}] address@hidden @var{filename}
address@hidden info [-f @var{fmt}] address@hidden [--backing-chain] 
@var{filename}
 
 Give information about the disk image @var{filename}. Use it in
 particular to know the size reserved on disk which can be different
@@ -137,6 +141,19 @@ from the displayed size. If VM snapshots are stored in the 
disk image,
 they are displayed too. The command can output in the format @var{ofmt}
 which is either @code{human} or @code{json}.
 
+If a disk image has a backing file chain, information about each disk image in
+the chain can be recursively enumerated by using the option 
@code{--backing-chain}.
+
+For instance, if you have an image chain like: 
+
+    base.qcow2 <- snap1.qcow2 <- snap2.qcow2 
+
+To enumerate information about each disk image in the above chain, starting 
from top to base, do:
+    
+    @example
+    qemu-img info --backing-chain snap2.qcow2
+    @end example
+
 @item snapshot [-l | -a @var{snapshot} | -c @var{snapshot} | -d @var{snapshot} 
] @var{filename}
 
 List, apply, create or delete snapshots in image @var{filename}.
-- 
1.7.12.1