Re: audio fs emulation

Riley Williams (rhw@BigFoot.Com)
Mon, 26 Apr 1999 10:39:01 +0100 (GMT)


Hi Senko.

>> I haven't had a chance to look at this yet, never mind try it
>> out, but there's one thing I'd be interested in knowing: How
>> does it handle dual-mode CD's (those with a combination of data
>> and audio tracks) ???

> It doesn't. It just displays data tracks, but (at present) can't
> access them.

>> I'd like to see it handle those by one of the following, but
>> have no idea if either is possible:

>> 1. "mount /dev/cdrom" results in a separate directory called
>> /audio appearing with the relevant files within it.

> Hmm...(imho) that would need redesigning complete isofs code and
> adding audio support for it. If it's possible (isofs uses normal
> bread, audiofs passes calls to cd ioctls) at all...

Alternatively, set up the isofs code so if it finds any audio tracks
on the CD and /proc/filesystems includes audiofs, it adds a virtual
directory called audio to the root directory of the CD with a file
entry for each audio track found, and does a hidden loopback mount via
audiofs as required...

>> 2. "mount /dev/cdrom" can be used twice, once each with iso9660
>> and audiofs as the mount type, with different mount points.

> I don't think so. VFS "locks" mounted device (afaik). One could
> do fs emulation that bypasses VFS but that would be a really
> ugly hack.

I'll agree with that...

>> Comments?

> I think the easiest (but probably not the best) way to do it is
> that audiofs would read data tracks, and then those tracks
> (files) would be mounted using loopback device...

Alternatively do the reverse, as above...

Best wishes from Riley.

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