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SubjectRe: 2.6.0, cdrom still showing directories after being erased
Quote from Martin Schlemmer <azarah@nosferatu.za.org>:
>
> --=-jU1p/KAdUL1ChKMTod+5
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: quoted-printable
>
> On Wed, 2004-02-04 at 00:40, Jens Axboe wrote:
> > On Tue, Feb 03 2004, Richard B. Johnson wrote:
> > > On Tue, 3 Feb 2004, [iso-8859-1] M=C3=A5ns Rullg=C3=A5rd wrote:
> > >=20
> > > > John Bradford <john@grabjohn.com> writes:
> > > >
> > > > > Regardless of specs, I don't know what the majority of devices in t=
> he
> > > > > real world actually do. Maybe Jens and Alan, (cc'ed), can help.
> > > >
> > > > Just tested with an ASUS SCB-2408 in my laptop. It gives read errors
> > > > after doing a fast erase, just like it should.
> > > >
> > > > --
> > > > M=C3=A5ns Rullg=C3=A5rd
> > > > mru@kth.se
> > > > -
> > >=20
> > > I had to borrow a R/W CDROM because most everybody uses CR-R only
> > > here. That's why it took so long to check. With SCSI, Linux 2.4.24,
> > > cdrecord fails to umount the drive before it burns it. The result
> > > is that the previous directory still remains at the mount-point.
> > > This, even though cdrecord ejected the drive to "re-read" its
> > > status.
> > >=20
> > > Bottom line: If the CDROM isn't umounted first, you can still
> > > get a directory entry even though the CDROM has been written with
> > > about 500 magabytes of new data.
> >=20
> > So what? Just because you can do it, doesn't mean it's a valid thing to
> > do. You can literally come up with thousands of similar weird things, if
> > you wanted to.
> >=20
> > This whole discussion is silly and pointless.
>
> I am assuming its cdrecord's responsibility to check if the device is
> not in use? How difficult will it be to add a kernel side stopper to
> this (as it will after all also stop this thread) ?

The problem you are discussing now is completely different to what we
were originally discussing, and almost completely pointless.

Of course you get problems if a raw devices changes underneath a
mounted filesystem, I would expect that. That is _NOT_ what we were
talking about _AT ALL_. The point is that the device itself caches
the state of the disc over an erase, so even if the device is
unmounted before an erase, when it is re-mounted, the stale data is
read from the device's own cache, which should have been invalidated
by the erase.

John.
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