From 6bff597bf6580ecc691258e849f652911dbdda7c Mon Sep 17 00:00:00 2001 From: Peter Krempa Date: Thu, 12 Oct 2017 16:14:10 +0200 Subject: block: don't add 'driver' to options when referring to backing via node name When referring to a backing file of an image via node name bdrv_open_backing_file would add the 'driver' option to the option list filling it with the backing format driver. This breaks construction of the backing chain via -blockdev, as bdrv_open_inherit reports an error if both 'reference' and 'options' are provided. $ qemu-img create -f raw /tmp/backing.raw 64M $ qemu-img create -f qcow2 -F raw -b /tmp/backing.raw /tmp/test.qcow2 $ qemu-system-x86_64 \ -blockdev driver=file,filename=/tmp/backing.raw,node-name=backing \ -blockdev driver=qcow2,file.driver=file,file.filename=/tmp/test.qcow2,node-name=root,backing=backing qemu-system-x86_64: -blockdev driver=qcow2,file.driver=file,file.filename=/tmp/test.qcow2,node-name=root,backing=backing: Could not open backing file: Cannot reference an existing block device with additional options or a new filename Signed-off-by: Peter Krempa Signed-off-by: Kevin Wolf --- block.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'block.c') diff --git a/block.c b/block.c index 46eb1728da..684cb018da 100644 --- a/block.c +++ b/block.c @@ -2245,7 +2245,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, goto free_exit; } - if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) { + if (!reference && + bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) { qdict_put_str(options, "driver", bs->backing_format); } -- cgit v1.2.1