From: Christoph Hellwig <hch@infradead.org>
To: David Chinner <dgc@sgi.com>
Cc: xfs-dev <xfs-dev@sgi.com>, xfs-oss <xfs@oss.sgi.com>
Subject: Re: review: handle barriers being switched off dynamically.
Date: Mon, 23 Apr 2007 22:23:36 +0100 [thread overview]
Message-ID: <20070423212336.GC13572@infradead.org> (raw)
In-Reply-To: <20070419073714.GU48531920@melbourne.sgi.com>
On Thu, Apr 19, 2007 at 05:37:14PM +1000, David Chinner wrote:
>
> As pointed out by Neil Brown, MD can switch barriers off
> dynamically underneath a mounted filesystem. If this happens
> to XFS, it will shutdown the filesystem immediately.
>
> Handle this more sanely by yelling into the syslog, retrying
> the I/O without barriers and if that is successful, turn
> off barriers.
>
> Also remove an unnecessary check when first checking to
> see if the underlying device supports barriers.
Looks good to me (well, not really good, but as good as it can
be given the circumstances..)
> + /*
> + * We can get an EOPNOTSUPP to ordered writes. Here we clear the
> + * ordered flag and reissue them. Because we can't tell the higher
> + * layers directly that they should not issue ordered I/O anymore, they
> + * need to check if the ordered flag was cleared during I/O completion.
> + */
> + if ((bp->b_error == EOPNOTSUPP) &&
no need for the additional braces here, though.
prev parent reply other threads:[~2007-04-23 21:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-19 7:37 review: handle barriers being switched off dynamically David Chinner
2007-04-23 21:23 ` Christoph Hellwig [this message]
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