From: Christoph Hellwig <hch@infradead.org>
To: Bgs <bgs@bgs.hu>
Cc: SGI Project XFS mailing list <xfs@oss.sgi.com>
Subject: Re: fs change on read-only mount
Date: Thu, 13 Aug 2009 09:14:07 -0400 [thread overview]
Message-ID: <20090813131407.GA1088@infradead.org> (raw)
In-Reply-To: <4A84090A.6040601@bgs.hu>
On Thu, Aug 13, 2009 at 02:37:30PM +0200, Bgs wrote:
>
> Greetings,
>
> I don't know xfs' superblock handling well enough, so I'm asking for
> advice here:
>
> Does xfs write anything on the disk when mounting read-only? Is it
> possible to use a partitions hash (or some well defined portion of the
> partition) for integrity checks?
It should not write anything to disk [1], but older versions did so due to
bugs. Doing a hash of a read-only filesystem should be fine.
> The partitions are used read-only and hash would be re-generated if any
> rw action was done (after remount ro or full reboot of course). Can this
> be done? I'm concerned about 'mount count' like writes...
There is no mount-count like write in XFS.
[1] the only exception is that log reocvery is performed when we attempt
a read-only mount with an unclean log, that is the box crashed while
writing the filesystems. To make sure you never do this always mark
the underlying device readonly, using blkdev --ro.
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next prev parent reply other threads:[~2009-08-13 13:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-13 12:37 fs change on read-only mount Bgs
2009-08-13 13:14 ` Christoph Hellwig [this message]
2009-08-13 13:47 ` Bgs
2009-08-13 13:49 ` Christoph Hellwig
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