Patchwork [v8,4/4] Add qemu-img compare documentation

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Submitter Miroslav Rezanina
Date Jan. 14, 2013, 10:26 a.m.
Message ID <107b8c42c613daa5b64e0f4d0281d12e92ebd61d.1358148502.git.mrezanin@redhat.com>
Download mbox | patch
Permalink /patch/211756/
State New
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Comments

Miroslav Rezanina - Jan. 14, 2013, 10:26 a.m.
Adding documentation for new qemu-img subcommand compare.

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 qemu-img.c    |    7 ++++++-
 qemu-img.texi |   32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletions(-)
Eric Blake - Jan. 14, 2013, 11:24 p.m.
On 01/14/2013 03:26 AM, Miroslav Rezanina wrote:
> Adding documentation for new qemu-img subcommand compare.
> 
> Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
> ---
>  qemu-img.c    |    7 ++++++-
>  qemu-img.texi |   32 ++++++++++++++++++++++++++++++++
>  2 files changed, 38 insertions(+), 1 deletions(-)

Your series is lacking a test case; it would be useful to test both
identical images, images that are identical only when not in strict
mode, and differing images.

> +Check if two images have the same content. You can compare images with
> +different format or settings.
> +
> +The format is probed unless you specify it by @var{-f} (used for @var{filename1}) and/or @var{-F} (used for @var{filename2}) option.

Long line; worth wrapping.
Kevin Wolf - Jan. 29, 2013, 11:33 a.m.
Am 14.01.2013 11:26, schrieb Miroslav Rezanina:
> Adding documentation for new qemu-img subcommand compare.
> 
> Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
> ---
>  qemu-img.c    |    7 ++++++-
>  qemu-img.texi |   32 ++++++++++++++++++++++++++++++++
>  2 files changed, 38 insertions(+), 1 deletions(-)

Ah, I see, here is the documentation. Please consider merging it into
patch 3.

Also please add a description of the exit codes.

Kevin

Patch

diff --git a/qemu-img.c b/qemu-img.c
index 0c12692..6aebdc3 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -103,7 +103,12 @@  static void help(void)
            "  '-a' applies a snapshot (revert disk to saved state)\n"
            "  '-c' creates a snapshot\n"
            "  '-d' deletes a snapshot\n"
-           "  '-l' lists all snapshots in the given image\n";
+           "  '-l' lists all snapshots in the given image\n"
+           "\n"
+           "Parameters to compare subcommand:\n"
+           "  '-f' first image format\n"
+           "  '-F' second image format\n"
+           "  '-s' run in Strict mode - fail on different image size or sector allocation\n";
 
     printf("%s\nSupported formats:", help_msg);
     bdrv_iterate_format(format_print, NULL);
diff --git a/qemu-img.texi b/qemu-img.texi
index 4fdb19a..90f581a 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -84,6 +84,18 @@  deletes a snapshot
 lists all snapshots in the given image
 @end table
 
+Parameters to compare subcommand:
+
+@table @option
+
+@item -f
+First image format
+@item -F
+Second image format
+@item -s
+Strict mode - fail on on different image size or sector allocation
+@end table
+
 Command description:
 
 @table @option
@@ -117,6 +129,26 @@  it doesn't need to be specified separately in this case.
 
 Commit the changes recorded in @var{filename} in its base image.
 
+@item compare [-f @var{fmt}] [-F @var{fmt}] [-p] [-s] [-q] @var{filename1} @var{filename2}
+
+Check if two images have the same content. You can compare images with
+different format or settings.
+
+The format is probed unless you specify it by @var{-f} (used for @var{filename1}) and/or @var{-F} (used for @var{filename2}) option.
+
+By default, images with different size are considered identical if the larger
+image contains only unallocated and/or zeroed sectors in the area after the end
+of the other image. In addition, if any sector is not allocated in one image
+and contains only zero bytes in the second one, it is evaluated as equal. You
+can use Strict mode by specifying the @var{-s} option. When compare runs in
+Strict mode, it fails in case image size differs or a sector is allocated in
+one image and is not allocated in the second one.
+
+By default, compare prints out a result message. This message displays
+information that both images are same or the position of the first different
+byte. In addition, result message can report different image size in case
+Strict mode is used.
+
 @item convert [-c] [-p] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}
 
 Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to disk image @var{output_filename}