qapi: Convert blockdev_snapshot_sync

Unfortunately, this conversion required an additional change.

In the old QMP command, the 'snapshot-file' argument is specified as
optional. The idea is to take the snapshot internally if 'snapshot-file'
is not passed. However, internal snapshots are not supported yet so
the command returns a MissingParamater error if 'snapshot-file' is not
passed. Which makes the argument actually required and will cause
compatibility breakage if we change that in the future.

To fix this the QAPI converted blockdev_snapshot_sync command makes the
'snapshot-file' argument required. Again, in practice it's actually required,
so this is not incompatible.

If we do implement internal snapshots someday, we'll need a new argument
for it.

Note that this discussion doesn't affect HMP.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/hmp.c b/hmp.c
index db199b2..934e931 100644
--- a/hmp.c
+++ b/hmp.c
@@ -643,3 +643,22 @@ void hmp_block_resize(Monitor *mon, const QDict *qdict)
     qmp_block_resize(device, size, &errp);
     hmp_handle_error(mon, &errp);
 }
+
+void hmp_snapshot_blkdev(Monitor *mon, const QDict *qdict)
+{
+    const char *device = qdict_get_str(qdict, "device");
+    const char *filename = qdict_get_try_str(qdict, "snapshot-file");
+    const char *format = qdict_get_try_str(qdict, "format");
+    Error *errp = NULL;
+
+    if (!filename) {
+        /* In the future, if 'snapshot-file' is not specified, the snapshot
+           will be taken internally. Today it's actually required. */
+        error_set(&errp, QERR_MISSING_PARAMETER, "snapshot-file");
+        hmp_handle_error(mon, &errp);
+        return;
+    }
+
+    qmp_blockdev_snapshot_sync(device, filename, !!format, format, &errp);
+    hmp_handle_error(mon, &errp);
+}