Am 10.07.2013 um 19:09 hat Eric Blake geschrieben:
> On 07/10/2013 07:51 AM, Kevin Wolf wrote:
> > One of the major reasons for doing something new for -blockdev and
> > blockdev-add was that the old block layer code parses filenames instead
> > of just taking them literally. So we should really leave it untouched
> > when it's passing using the new interfaces (like -drive
> > file.filename=...).
> >
> > This allows opening relative file names that contain a colon.
>
> Will a protocol prefix ever contain a '/'? Would it be desirable to
> state that relative file names containing a colon should be specified as
> './file:name', with the '/' serving as the escape that means relative
> file rather than attempting to use protocol './file:', even when using
> legacy options?
In fact, that already works, but it's kind of non-obvious magic (see
path_has_protocol), whereas file.filename should works in a consistent
way.
> > Signed-off-by: Kevin Wolf <kw...@redhat.com>
> > ---
> > block.c | 17 ++++++++++++-----
> > block/sheepdog.c | 2 +-
> > include/block/block.h | 3 ++-
> > qemu-img.c | 4 ++--
> > tests/qemu-iotests/051 | 12 ++++++++++++
> > tests/qemu-iotests/051.out | 14 ++++++++++++++
> > 6 files changed, 43 insertions(+), 9 deletions(-)
>
> >
> > @@ -813,7 +817,10 @@ int bdrv_file_open(BlockDriverState **pbs, const char
> > *filename,
> > drv = bdrv_find_whitelisted_format(drvname, !(flags &
> > BDRV_O_RDWR));
> > qdict_del(options, "driver");
> > } else if (filename) {
> > - drv = bdrv_find_protocol(filename);
> > + drv = bdrv_find_protocol(filename, allow_protocol_prefix);
> > + if (!drv) {
> > + qerror_report(ERROR_CLASS_GENERIC_ERROR, "Unknown protocol");
> > + }
>
> If you want to allow './' as a forceful non-protocol escape even in
> legacy parsing, then this code may need tweaking. Otherwise, I think
> the code looks fine.
>
> Reviewed-by: Eric Blake <ebl...@redhat.com>
>
> > +++ b/tests/qemu-iotests/051
> > @@ -149,6 +149,18 @@ echo
> > run_qemu -drive file=$TEST_IMG,file.driver=file
> > run_qemu -drive file=$TEST_IMG,file.driver=qcow2
> >
> > +echo
> > +echo === Parsing protocol from file name ===
> > +echo
> > +
> > +# Protocol strings are supposed to be parsed from traditional option
> > strings,
> > +# but not when using driver-specific options. We can distinguish them by
> > the
> > +# error message for non-existing files.
>
> Is it also worth testing that we successfully open a file name with a
> colon from driver-specific options, or is that harder to do portably
> (since windows doesn't allow : in file names except for the drive prefix)?
The hard thing is that $TEST_DIR and $TEST_IMG are absolute paths and I
would need relative ones to test this. And I don't want to create files
outside the test directory.
We don't really care about portability in qemu-iotests (and there's
always '_supported_os Linux').
Kevin
