vmdk already requires that if backing_file is present, that it be
another vmdk image (see vmdk_co_do_create). Meanwhile, we want to
move towards always being explicit about the backing format for other
drivers where it matters. So for convenience, make qemu-img create -F
vmdk work, while rejecting all other explicit formats (note that this
is only for QemuOpts usage; there is no change to the QAPI to allow a
format through -blockdev).
Signed-off-by: Eric Blake <eblake@xxxxxxxxxx>
---
block/vmdk.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/block/vmdk.c b/block/vmdk.c
index 20e909d99794..3c7893817afe 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -2611,6 +2611,14 @@ static int coroutine_fn vmdk_co_create_opts(const char *filename, QemuOpts *opts
bool zeroed_grain;
bool compat6;
VMDKCreateOptsData data;
+ char *backing_fmt = NULL;
+
+ backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
+ if (backing_fmt && strcmp(backing_fmt, "vmdk") != 0) {
+ error_setg(errp, "backing_file must be a vmdk image");
+ ret = -EINVAL;
+ goto exit;
+ }
if (filename_decompose(filename, path, prefix, postfix, PATH_MAX, errp)) {
ret = -EINVAL;
@@ -2669,6 +2677,7 @@ static int coroutine_fn vmdk_co_create_opts(const char *filename, QemuOpts *opts
vmdk_co_create_opts_cb, &data, errp);
exit:
+ g_free(backing_fmt);
g_free(adapter_type);
g_free(backing_file);
g_free(hw_version);
@@ -3005,6 +3014,11 @@ static QemuOptsList vmdk_create_opts = {
.type = QEMU_OPT_STRING,
.help = "File name of a base image"
},
+ {
+ .name = BLOCK_OPT_BACKING_FMT,
+ .type = QEMU_OPT_STRING,
+ .help = "Must be 'vmdk' if present",
+ },
{
.name = BLOCK_OPT_COMPAT6,
.type = QEMU_OPT_BOOL,
--
2.25.1
