On Tue, 04/08 14:50, Max Reitz wrote:
> Introduce a new parameter for qemu-img commit which may be used to
> explicitly specify the backing file unto which an image should be
> committed if the backing chain has more than a single layer.
>
> Signed-off-by: Max Reitz <mre...@redhat.com>
> ---
> qemu-img-cmds.hx | 4 ++--
> qemu-img.c | 22 +++++++++++++++-------
> qemu-img.texi | 8 +++++++-
> 3 files changed, 24 insertions(+), 10 deletions(-)
>
> diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
> index 8bc55cd..7f62f6d 100644
> --- a/qemu-img-cmds.hx
> +++ b/qemu-img-cmds.hx
> @@ -22,9 +22,9 @@ STEXI
> ETEXI
>
> DEF("commit", img_commit,
> - "commit [-q] [-f fmt] [-t cache] [-p] filename")
> + "commit [-q] [-f fmt] [-t cache] [-b backing_file] [-p] filename")
> STEXI
> -@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-p] @var{filename}
> +@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-b @var{backing_file}]
> [-p] @var{filename}
> ETEXI
>
> DEF("compare", img_compare,
> diff --git a/qemu-img.c b/qemu-img.c
> index 0a9eff7..9d4bdbc 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -725,15 +725,16 @@ static void run_block_job(BlockJob *job, Error **errp)
> static int img_commit(int argc, char **argv)
> {
> int c, ret, flags;
> - const char *filename, *fmt, *cache;
> + const char *filename, *fmt, *cache, *base;
> BlockDriverState *bs, *base_bs;
> bool progress = false, quiet = false;
> Error *local_err = NULL;
>
> fmt = NULL;
> cache = BDRV_DEFAULT_CACHE;
> + base = NULL;
> for(;;) {
> - c = getopt(argc, argv, "f:ht:qp");
> + c = getopt(argc, argv, "f:ht:b:qp");
> if (c == -1) {
> break;
> }
> @@ -748,6 +749,9 @@ static int img_commit(int argc, char **argv)
> case 't':
> cache = optarg;
> break;
> + case 'b':
> + base = optarg;
> + break;
> case 'p':
> progress = true;
> break;
> @@ -782,12 +786,16 @@ static int img_commit(int argc, char **argv)
> qemu_progress_init(progress, 1.f);
> qemu_progress_print(0.f, 100);
>
> - /* This is different from QMP, which by default uses the deepest file in
> the
> - * backing chain (i.e., the very base); however, the traditional
> behavior of
> - * qemu-img commit is using the immediate backing file. */
> - base_bs = bs->backing_hd;
> + if (base) {
> + base_bs = bdrv_find_backing_image(bs, base);
> + } else {
> + /* This is different from QMP, which by default uses the deepest
> file in
> + * the backing chain (i.e., the very base); however, the traditional
> + * behavior of qemu-img commit is using the immediate backing file.
> */
> + base_bs = bs->backing_hd;
> + }
> if (!base_bs) {
> - error_set(&local_err, QERR_BASE_NOT_FOUND, "NULL");
> + error_set(&local_err, QERR_BASE_NOT_FOUND, base ?: "NULL");
> goto done;
> }
>
> diff --git a/qemu-img.texi b/qemu-img.texi
> index 1a9c08f..4a9f493 100644
> --- a/qemu-img.texi
> +++ b/qemu-img.texi
> @@ -140,7 +140,7 @@ 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}] [-p] @var{filename}
> +@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-b @var{backing_file}]
> [-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
> @@ -149,6 +149,12 @@ the backing file, the backing file will not be
> truncated. If you want the
> backing file to match the size of the smaller snapshot, you can safely
> truncate
> it yourself once the commit operation successfully completes.
>
> +If the backing chain of the given image file @var{filename} has more than one
> +layer, the backing file unto which the changes shall be committed may be
> +specified as @var{backing_file} (which has to be part of @var{filename}'s
> +backing chain). If @var{filename} is not specified, the immediate backing
> file
s/@var{filename}/@var{backing_file}/ ?
BTW how about just calling it 'base' as in qmp commands, because backing_file
has usages in (slightly) different context of create.
Other than the two questions,
Reviewed-by: Fam Zheng <f...@redhat.com>
> +of the top image (which is @var{filename}) will be used.
> +
> @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
> --
> 1.9.1
>
>
