[PATCH 1/6] xfs: optimize AGFL refills

[Christoph Hellwig]

> The reason it was not obvious is because the case you're
> treating is specifically when moving extents (blocks,
> really) between the free list and the free btrees, in
> xfs_alloc_fix_freelist().  You still need to force it
> out when allocating and freeing "actually used" blocks,
> which could also be considered "moving blocks from/to
> the AGFL."

I've updated the comment to make that more clear.