Re: [Linux-cluster] Re: GFS, what's remaining

[Joel Becker <Joel.Becker@oracle.com>]

On Sat, Sep 03, 2005 at 10:41:40PM -0700, Andrew Morton wrote:
> Are you saying that the posix-file lookalike interface provides access to
> part of the functionality, but there are other APIs which are used to
> access the rest of the functionality?  If so, what is that interface, and
> why cannot that interface offer access to 100% of the functionality, thus
> making the posix-file tricks unnecessary?

	Currently, this is all the interface that the OCFS2 DLM
provides.  But yes, if you wanted to provide the rest of the VMS
functionality (something that GFS2's DLM does), you'd need to use a more
concrete interface.
	IMHO, it's worthwhile to have a simple interface, one already
used by mkfs.ocfs2, mount.ocfs2, fsck.ocfs2, etc.  This is an interface
that can and is used by shell scripts even (we do this to test the DLM).
If you make it a C-library-only interface, you've just restricted the
subset of folks that can use it, while adding programming complexity.
	I think that a simple fs-based interface can coexist with a more
complex one.  FILE* doesn't give you the flexibility of read()/write(),
but I wouldn't remove it :-)

Joel

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Joel Becker
Senior Member of Technical Staff
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127