@@ -1145,11 +1145,14 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
qdict_extract_subqdict(options, &file_options, "file.");
file_reference = qdict_get_try_str(options, "file");
- ret = bdrv_file_open(&file, filename, file_reference, file_options,
- bdrv_open_flags(bs, flags | BDRV_O_UNMAP), &local_err);
- qdict_del(options, "file");
- if (ret < 0) {
- goto fail;
+ if (filename || file_reference || qdict_size(file_options)) {
+ ret = bdrv_file_open(&file, filename, file_reference, file_options,
+ bdrv_open_flags(bs, flags | BDRV_O_UNMAP),
+ &local_err);
+ qdict_del(options, "file");
+ if (ret < 0) {
+ goto fail;
+ }
}
/* Find the right image format driver */
@@ -1165,7 +1168,13 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
}
if (!drv) {
- ret = find_image_format(file, filename, &drv, &local_err);
+ if (file) {
+ ret = find_image_format(file, filename, &drv, &local_err);
+ } else {
+ error_setg(errp, "Must specify either driver or file");
+ ret = -EINVAL;
+ goto unlink_and_fail;
+ }
}
if (!drv) {
@@ -1178,7 +1187,7 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
goto unlink_and_fail;
}
- if (bs->file != file) {
+ if (file && (bs->file != file)) {
bdrv_unref(file);
file = NULL;
}
blkdebug and blkverify will, in order to retain compatibility, not support the field "file" implicitly through bdrv_open(). In order to be able to use those drivers without giving a filename anyway, it is necessary to be able to have block devices without files implicitly opened by bdrv_open(). This is the case, if there was neither a file name, a reference to an existing block device to use as a file nor options specific to the file. Signed-off-by: Max Reitz <mreitz@redhat.com> --- block.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-)