[PATCH 07/12] xfs: remote attribute tail zeroing does too much

[Ben Myers]

On Fri, Jun 07, 2013 at 10:24:56PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner at redhat.com>
> 
> When an attribute data does not fill then entire remote block, we
> zero the remaining part of the buffer. This, however, needs to take
> into account that the buffer has a header, and so the offset where
> zeroing starts and the length of zeroing need to take this into
> account. Otherwise we end up with zeros over the end of the
> attribute value when CRCs are enabled.
> 
> While there, make sure we only ask to map an extent that covers the
> remaining range of the attribute, rather than asking every time for
> the full length of remote data. If the remote attribute blocks are
> contiguous with other parts of the attribute tree, it will map those
> blocks as well and we can potentially zero them incorrectly. We can
> also get buffer size mistmatches when trying to read or remove the
> remote attribute, and this can lead to not finding the correct
> buffer when looking it up in cache.
> 
> Signed-off-by: Dave Chinner <dchinner at redhat.com>

Goes with commit 4af3644c9a53eb2f1ecf69cc53576561b64be4c6

Reviewed-by: Ben Myers <bpm at sgi.com>