diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2013-03-18 16:40:51 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2013-03-22 17:51:32 +0100 |
| commit | c2ad1b0c465a9ea8375eaff14bbd85705c673f73 (patch) | |
| tree | 705456a5885c9ac7223fa2b75158e09adbc1d38f /include/block | |
| parent | f5866fa438bff586f215c137dc71edb4e0770536 (diff) | |
block: Allow omitting the file name when using driver-specific options
After this patch, using -drive with an empty file name continues to open
the file if driver-specific options are used. If no driver-specific
options are specified, the semantics stay as it was: It defines a drive
without an inserted medium.
In order to achieve this, bdrv_open() must be made safe to work with a
NULL filename parameter. The assumption that is made is that only block
drivers which implement bdrv_parse_filename() support using driver
specific options and could therefore work without a filename. These
drivers must make sure to cope with NULL in their implementation of
.bdrv_open() (this is only NBD for now). For all other drivers, the
block layer code will make sure to error out before calling into their
code - they can't possibly work without a filename.
Now an NBD connection can be opened like this:
qemu-system-x86_64 -drive file.driver=nbd,file.port=1234,file.host=::1
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'include/block')
| -rw-r--r-- | include/block/block_int.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/block/block_int.h b/include/block/block_int.h index 1b06a11590..0986a2d6ac 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -75,6 +75,9 @@ struct BlockDriver { int instance_size; int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); int (*bdrv_probe_device)(const char *filename); + + /* Any driver implementing this callback is expected to be able to handle + * NULL file names in its .bdrv_open() implementation */ void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp); /* For handling image reopen for split or non-split files */ |