From 1b22bffd829ee3db4ddcfbd7e66c7a7921123f3e Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Fri, 24 Oct 2014 15:57:40 +0200 Subject: qemu-img: Specify backing file for commit Introduce a new parameter for qemu-img commit which may be used to explicitly specify the backing file into which an image should be committed if the backing chain has more than a single layer. [Applied Eric Blake's qemu-img.texi documentation rewording --Stefan] Signed-off-by: Max Reitz Reviewed-by: Kevin Wolf Reviewed-by: Eric Blake Message-id: 1414159063-25977-12-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi --- qemu-img.texi | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'qemu-img.texi') diff --git a/qemu-img.texi b/qemu-img.texi index f82d1b4923..078851adb6 100644 --- a/qemu-img.texi +++ b/qemu-img.texi @@ -167,7 +167,7 @@ this case. @var{backing_file} will never be modified unless you use the The size can also be specified using the @var{size} option with @code{-o}, it doesn't need to be specified separately in this case. -@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-d] [-p] @var{filename} +@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-b @var{base}] [-d] [-p] @var{filename} Commit the changes recorded in @var{filename} in its base image or backing file. If the backing file is smaller than the snapshot, then the backing file will be @@ -180,6 +180,16 @@ The image @var{filename} is emptied after the operation has succeeded. If you do not need @var{filename} afterwards and intend to drop it, you may skip emptying @var{filename} by specifying the @code{-d} flag. +If the backing chain of the given image file @var{filename} has more than one +layer, the backing file into which the changes will be committed may be +specified as @var{base} (which has to be part of @var{filename}'s backing +chain). If @var{base} is not specified, the immediate backing file of the top +image (which is @var{filename}) will be used. For reasons of consistency, +explicitly specifying @var{base} will always imply @code{-d} (since emptying an +image after committing to an indirect backing file would lead to different data +being read from the image due to content in the intermediate backing chain +overruling the commit target). + @item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s] [-q] @var{filename1} @var{filename2} Check if two images have the same content. You can compare images with -- cgit v1.2.3