Providing backing.file.filename doesn't override backing file as expected:
$ x86_64-softmmu/qemu-system-x86_64 -drive \
file=/tmp/child.qcow2,backing.file.filename=/tmp/fake.qcow2
qemu-system-x86_64: -drive \
file=/tmp/child.qcow2,backing.file.filename=/tmp/fake.qcow2: could not
open disk image /tmp/child.qcow2: Can't specify 'file' and 'filename'
options at the same time
With
$ qemu-img info /tmp/child.qcow2
image: /tmp/child.qcow2
file format: qcow2
virtual size: 1.0G (1073741824 bytes)
disk size: 196K
cluster_size: 65536
backing file: /tmp/fake.qcow2
This fixes it by calling bdrv_get_full_backing_filename only if
backing.file.filename is not provided. Also save the backing file name
to bs->backing_file so the information is correct with HMP "info block".
Signed-off-by: Fam Zheng <f...@redhat.com>
---
block.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/block.c b/block.c
index e176c6f..a2ea39a 100644
--- a/block.c
+++ b/block.c
@@ -978,11 +978,12 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict
*options, Error **errp)
} else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
QDECREF(options);
return 0;
+ } else {
+ bdrv_get_full_backing_filename(bs, backing_filename,
+ sizeof(backing_filename));
}
bs->backing_hd = bdrv_new("");
- bdrv_get_full_backing_filename(bs, backing_filename,
- sizeof(backing_filename));
if (bs->backing_format[0] != '\0') {
back_drv = bdrv_find_format(bs->backing_format);
@@ -994,6 +995,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict
*options, Error **errp)
ret = bdrv_open(bs->backing_hd,
*backing_filename ? backing_filename : NULL, options,
back_flags, back_drv, &local_err);
+ pstrcpy(bs->backing_file, sizeof(bs->backing_file),
+ bs->backing_hd->file->filename);
if (ret < 0) {
bdrv_unref(bs->backing_hd);
bs->backing_hd = NULL;
--
1.8.3.1
