[Qemu-devel] [PATCH v8 4/4] Add qemu-img compare documentation

[Miroslav Rezanina]

Adding documentation for new qemu-img subcommand compare.

Signed-off-by: Miroslav Rezanina <address@hidden>
---
 qemu-img.c    |    7 ++++++-
 qemu-img.texi |   32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletions(-)

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:
+
address@hidden @option
+
address@hidden -f
+First image format
address@hidden -F
+Second image format
address@hidden -s
+Strict mode - fail on on different image size or sector allocation
address@hidden 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.
 
address@hidden 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} address@hidden [...]] @var{output_filename}
 
 Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to 
disk image @var{output_filename}
-- 
1.7.1