If a format BDS's file BDS is in turn a format BDS, we cannot simply use
the same filename, because when opening a BDS tree based on a filename
alone, qemu will create only one format node on top of one protocol node
(disregarding a potential backing file).
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/block.c b/block.c
index 2d3e07b7a7..c4aec7ea65 100644
--- a/block.c
+++ b/block.c
@@ -5355,9 +5355,21 @@ void bdrv_refresh_filename(BlockDriverState *bs)
bs->exact_filename[0] = '\0';
- /* If no specific options have been given for this BDS, the filename of
- * the underlying file should suffice for this one as well */
- if (bs->file->bs->exact_filename[0] && !generate_json_filename) {
+ /*
+ * We can use the underlying file's filename if:
+ * - it has a filename,
+ * - the file is a protocol BDS, and
+ * - opening that file (as this BDS's format) will automatically create
+ * the BDS tree we have right now, that is:
+ * - the user did not significantly change this BDS's behavior with
+ * some explicit (strong) options
+ * - no non-file child of this BDS has been overridden by the user
+ * Both of these conditions are represented by
generate_json_filename.
+ */
+ if (bs->file->bs->exact_filename[0] &&
+ bs->file->bs->drv->bdrv_file_open &&
+ !generate_json_filename)
+ {
strcpy(bs->exact_filename, bs->file->bs->exact_filename);
}
}
--
2.17.1
