On Wed, Aug 11, 2021 at 05:58:47PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <djwong@xxxxxxxxxx> > > The fsmap implementation for realtime devices uses the gap between > info->next_daddr and a free rtextent reported by xfs_rtalloc_query_range > to feed userspace fsmap records with an "unknown" owner. We use this > trick to report to userspace when the last rtextent in the filesystem is > in use by synthesizing a null rmap record starting at the next block > after the query range. > > Unfortunately, there's a minor accounting bug in the way that we > construct the null rmap record. Originally, ahigh.ar_startext contains > the last rtextent for which the user wants records. It's entirely > possible that number is beyond the end of the rt volume, so the location > synthesized rmap record /must/ be constrained to the minimum of the high > key and the number of extents in the rt volume. Looks good, although the change is a little hard to follow due to the big amount of cleanups vs the tiny actual bug fix. Reviewed-by: Christoph Hellwig <hch@xxxxxx>
