> In the patch I mention above I estimate the amount of space this metadata
> will take if the whole disk were full based on the part that *is* full,
> and subtract that estimate from the total partition size to fill in
> f_blocks.  f_bfree and f_avail are similarly estimated.

How about leaving f_blocks as the full size of the partition, and
extending the statfs interface so that it takes up one or maybe two of
the f_spare[] fields for "f_used" and maybe "f_metaused"?

						- Bill