block: Allow block devices without files

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>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2013-12-20 19:28:10 +01:00 committed by Kevin Wolf
parent 2258e3fe20
commit 2a05cbe426

23
block.c
View File

@ -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;
}