On Tue, Jun 20, 2023 at 12:09:39PM +1000, Dave Chinner wrote: > On Thu, May 25, 2023 at 05:28:08PM -0700, Darrick J. Wong wrote: > > Hi all, > > > > As part of merging the parent pointers patchset into my development > > branch, I noticed a few problems with the GETFSMAP implementation for > > XFS. The biggest problem is that ranged queries don't work properly if > > the query interval is exactly within a single record. It turns out that > > I didn't implement the record filtering quite right -- for the first > > call into the btree code, we want to find any rmap that overlaps with > > the range specified, but for subsequent calls, we only want rmaps that > > come after the low key of the query. This can be fixed by tweaking the > > filtering logic and pushing the key handling into the individual backend > > implementations. > > > > The second problem I noticed is that there are integer overflows in the > > rtbitmap and external log handlers. This is the result of a poor > > decision on my part to use the incore rmap records for storing the query > > ranges; this only works for the rmap code, which is smart enough to > > iterate AGs. This breaks down spectacularly if someone tries to query > > high block offsets in either the rt volume or the log device. I fixed > > that by introducing a second filtering implementation based entirely on > > daddrs. > > > > The third problem was minor by comparison -- the rt volume cannot ever > > use rtblocks beyond the end of the last rtextent, so it makes no sense > > for GETFSMAP to try to query those areas. > > > > Having done that, add a few more patches to clean up some messes. > > > > If you're going to start using this mess, you probably ought to just > > pull from my git trees, which are linked below. > > > > This is an extraordinary way to destroy everything. Enjoy! > > Comments and questions are, as always, welcome. > > > > --D > > > > kernel git tree: > > https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=getfsmap-fixes > > > > xfsprogs git tree: > > https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=getfsmap-fixes > > --- > > fs/xfs/libxfs/xfs_alloc.c | 10 -- > > fs/xfs/libxfs/xfs_refcount.c | 13 +- > > fs/xfs/libxfs/xfs_rmap.c | 10 -- > > fs/xfs/xfs_fsmap.c | 261 ++++++++++++++++++++++-------------------- > > fs/xfs/xfs_trace.h | 25 ++++ > > 5 files changed, 177 insertions(+), 142 deletions(-) > > Changes look sensible, but I know my limits: I'm not going to find > off-by-one problems in this code during review. > > Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx> Oh, heh, thanks for the review! I guess I'll go spin the for-next bottle again... --D > -- > Dave Chinner > david@xxxxxxxxxxxxx
