Re: [RFC] mount flag "direct"

Maciej W. Rozycki
2002-09-03T15:49:00Z

On Tue, 3 Sep 2002, Rik van Riel wrote:

> > Rationale:
> > No caching means that each kernel doesn't go off with its own idea of
> > what is on the disk in a file, at least. Dunno about directories and
> > metadata.
>
> And what if they both allocate the same disk block to another
> file, simultaneously ?

You need a mutex then. For SCSI devices a reservation is the way to go
-- the RESERVE/RELEASE commands are mandatory for direct-access devices,
so thy should work universally for disks.

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +