[Qemu-devel] [PATCH] Documentation: Warn against qemu-img on active image

[Kevin Wolf <kwolf@redhat.com>]

People have repeatedly expected that you can do things like snapshotting
an image with qemu-img while a qemu instance is running. Maybe we need
to consider locking the files while they are in use, but having a
warning in the qemu-img manpage is doable for 1.2 and can't hurt anyway.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu-img.texi |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/qemu-img.texi b/qemu-img.texi
index 77c6d0b..0b363e7 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -4,6 +4,14 @@ usage: qemu-img command [command options]
 @c man end
 @end example
 
+@c man begin DESCRIPTION
+qemu-img allows to create, convert and modify images offline. It can handle all
+image formats supported by QEMU.
+
+@b{Warning:} Never use qemu-img to modify images in use by a running virtual
+machine or any other process, this may destroy the image.
+@c man end
+
 @c man begin OPTIONS
 
 The following commands are supported:
-- 
1.7.6.5