Re: [PATCH 6/9] xfs: disable swap extents ioctl on CRC enabled filesystems

Ben Myers
2013-05-30T17:56:03Z

On Wed, May 29, 2013 at 05:06:08PM -0400, Brian Foster wrote:
> On 05/27/2013 02:38 AM, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > Currently, swapping extents from one inode to another is a simple
> > act of switching data and attribute forks from one inode to another.
> > This, unfortunately in no longer so simple with CRC enabled
> > filesystems as there is owner information embedded into the BMBT
> > blocks that are swapped between inodes. Hence swapping the forks
> > between inodes results in the inodes having mapping blocks that
> > point to the wrong owner and hence are considered corrupt.
> >
> > To fix this we need an extent tree block or record based swap
> > algorithm so that the BMBT block owner information can be updated
> > atomically in the swap transaction. This is a significant piece of
> > new work, so for the moment simply don't allow swap extent
> > operations to succeed on CRC enabled filesystems.
> >
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > ---
>
> Pretty straightforward...
>
> Reviewed-by: Brian Foster <bfoster@redhat.com>

Applied.