[Qemu-block] [PATCH RFC 1/1] block: Handle NULL options correctly in raw_open

[Dong Jia Shi]

A normal call for raw_open should always pass in a non-NULL @options,
but for some certain cases (e.g. trying to applying snapshot on a RBD
image), they call raw_open with a NULL @options right after the calling
for raw_close.

Let's take the NULL @options as a sign of trying to do raw_open again,
and just simply return a success code.

Signed-off-by: Dong Jia Shi <address@hidden>
---
 block/raw-format.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/block/raw-format.c b/block/raw-format.c
index 86fbc65..ee05730 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -384,6 +384,14 @@ static int raw_open(BlockDriverState *bs, QDict *options, 
int flags,
     BDRVRawState *s = bs->opaque;
     int ret;
 
+    /*
+     * Notice:
+     * NULL options is only sensible when applying a snapshot.
+     */
+    if (!options) {
+        return 0;
+    }
+
     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
                                false, errp);
     if (!bs->file) {
-- 
2.8.4