path: root/qemu-img.texi
diff options
authorMax Reitz <mreitz@redhat.com>2014-10-24 15:57:40 +0200
committerStefan Hajnoczi <stefanha@redhat.com>2014-11-03 11:41:48 +0000
commit1b22bffd829ee3db4ddcfbd7e66c7a7921123f3e (patch)
tree101b205f2b3bfe9fa3f8a9d1dc801f7799ba4fca /qemu-img.texi
parent687fa1d83013d56f7c7f9c008c956f4c26d8ba5c (diff)
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 <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1414159063-25977-12-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'qemu-img.texi')
1 files changed, 11 insertions, 1 deletions
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