Re: [PATCH 0/20] return f_fsid for statfs(2)

From: Dave Kleikamp
Date: Mon Jan 19 2009 - 21:39:29 EST

On Tue, 2009-01-20 at 07:36 +0800, Andreas Dilger wrote:
> On Jan 19, 2009 13:28 -0600, Dave Kleikamp wrote:
> > ext[234] return a portion of the uuid in f_fsid. There is a theoretical
> > chance of those values being non-unique. Since there doesn't appear to
> > be any case for the fsid to be persistent between boots, I guess
> > huge_encode_dev() is probably a better choice. In practice it probably
> > makes no difference.
> I'm not sure what you mean about "no case for fsid to be persistent"?
> The whole point of fsid (for NFS) is that this identifies the filesystem
> over reboot, even if the block device ID changes, or if the filesystem
> doesn't have a block device at all (e.g. cluster filesystem).

I guess that just demonstrates how little I know about what the fsid is
about. Would it be preferable for file systems that have a uuid to use
that instead? Of course anything is an improvement over zeroes.

David Kleikamp
IBM Linux Technology Center

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