Re: [PATCH] xfs: publish UUID in struct super_block

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Apr 28, 2017 at 06:49:45AM +0100, Andy Whitcroft wrote:
> On Thu, Apr 27, 2017 at 03:30:35PM -0500, Eric Sandeen wrote:
> 
> > It'd be trivial to make that a vfs function and set a flag on the vfs super
> > if the UUID is not unique.  Would that be worthwhile?  I can send a patch 
> > if so.
> 
> This only tells you that the UUID it has is unique now.  As you are
> contemplating storing them in the FS they have to be unique in space
> _and_ time.  No check you can do now can tell you if the UUID is unique
> for all time.  Right ?

Well, since we're talking about all time: "probably" :P

That said, Eric was talking about a refactoring of one of XFS's mount
time checks that errors out if there's already a mounted fs with the
same uuid.  We use it to avoid catastrophic mounting of the same fs from
multiple (misconfigured) multipaths/snapshots/volumes/whatever on the
same machine.  Not sure if that's useful for Amir's case.

--D

> 
> -apw
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