[PATCH 3/4] xfs: exact busy extent tracking

[Dave Chinner]

On Sun, Apr 24, 2011 at 03:06:16PM -0400, Christoph Hellwig wrote:
> Update the extent tree in case we have to reuse a busy extent, so that it
> always is kept uptodate.  This is done by replacing the busy list searches
> with a new xfs_alloc_busy_reuse helper, which updates the busy extent tree
> in case of a reuse.  This allows us to allow reusing metadata extents
> unconditionally, and thus avoid log forces especially for allocation btree
> blocks.

I'd add one comment to this - that this returns to the old way of
clearing busy extents by issuing a sync log force with the AGF
locked. This can cause additional allocation latency, but should be
rare given the occurrence of of metadata->data reallocation.

> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Reviewed-by: Alex Elder <aelder at sgi.com>

Otherwise,

Reviewed-by: Dave Chinner <dchinner at redhat.com>

-- 
Dave Chinner
david at fromorbit.com