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>
ETEXI
DEF("commit", img_commit,
ETEXI
DEF("commit", img_commit,
- "commit [-q] [-f fmt] [-t cache] [-d] [-p] filename")
+ "commit [-q] [-f fmt] [-t cache] [-b base] [-d] [-p] filename")
-@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}
ETEXI
DEF("compare", img_compare,
ETEXI
DEF("compare", img_compare,
static int img_commit(int argc, char **argv)
{
int c, ret, flags;
static int img_commit(int argc, char **argv)
{
int c, ret, flags;
- const char *filename, *fmt, *cache;
+ const char *filename, *fmt, *cache, *base;
BlockBackend *blk;
BlockDriverState *bs, *base_bs;
bool progress = false, quiet = false, drop = false;
BlockBackend *blk;
BlockDriverState *bs, *base_bs;
bool progress = false, quiet = false, drop = false;
fmt = NULL;
cache = BDRV_DEFAULT_CACHE;
fmt = NULL;
cache = BDRV_DEFAULT_CACHE;
- c = getopt(argc, argv, "f:ht:dpq");
+ c = getopt(argc, argv, "f:ht:b:dpq");
case 't':
cache = optarg;
break;
case 't':
cache = optarg;
break;
+ case 'b':
+ base = optarg;
+ /* -b implies -d */
+ drop = true;
+ break;
case 'd':
drop = true;
break;
case 'd':
drop = true;
break;
qemu_progress_init(progress, 1.f);
qemu_progress_print(0.f, 100);
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_bs) {
- error_setg(&local_err, "Image does not have a backing file");
- goto done;
+ if (base) {
+ base_bs = bdrv_find_backing_image(bs, base);
+ if (!base_bs) {
+ error_set(&local_err, QERR_BASE_NOT_FOUND, base);
+ goto done;
+ }
+ } 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_setg(&local_err, "Image does not have a backing file");
+ goto done;
+ }
}
cbi = (CommonBlockJobCBInfo){
}
cbi = (CommonBlockJobCBInfo){
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.
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
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
not need @var{filename} afterwards and intend to drop it, you may skip emptying
@var{filename} by specifying the @code{-d} flag.
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
@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