On Thu, Aug 12, 2021 at 09:36:52AM +0100, Christoph Hellwig wrote: > 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. I'll clean that up a bit before I commit this to the -merge branch. --D > Reviewed-by: Christoph Hellwig <hch@xxxxxx>
