Re: [PATCH 03/10] xfs: a few small tweaks for overwrites in xfs_vm_writepage

Dave Chinner
2010-12-01T04:05:25Z

On Mon, Nov 22, 2010 at 08:05:09AM -0500, Christoph Hellwig wrote:
> Don't trylock the buffer. We are the only one ever locking it for
> a regular file address space, and trylock was only copied from the
> generic code which did it due to the old buffer based writeout in
> jbd. Also make sure to only write out the buffer if the iomap
> actually is valid, because we wouldn't have a proper mapping
> otherwise. In practice we will never get an invalid mapping here
> as the page lock guarantees truncate doesn't race with us, but
> better be safe than sorry. Also make sure we allocate a new ioend
> when crossing boundaries between mappings, just like we do for
> delalloc and unwritten extents. Again this currently doesn't
> matter as the I/O end handler only cares for the boundaries for
> unwritten extents, but this makes the code fully correct and the
> same as for delalloc/unwritten extents.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com