On Fri, Oct 15, 2021 at 10:03:33AM +1100, Dave Chinner wrote:
> On Thu, Oct 14, 2021 at 01:18:11PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@xxxxxxxxxx>
> >
> > Instead of assuming that the hardcoded XFS_BTREE_MAXLEVELS value is big
> > enough to handle the maximally tall rmap btree when all blocks are in
> > use and maximally shared, let's compute the maximum height assuming the
> > rmapbt consumes as many blocks as possible.
> >
> > Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> > Reviewed-by: Chandan Babu R <chandan.babu@xxxxxxxxxx>
> > ---
> > fs/xfs/libxfs/xfs_btree.c | 33 +++++++++++++++++++++++++++++
> > fs/xfs/libxfs/xfs_btree.h | 2 ++
> > fs/xfs/libxfs/xfs_rmap_btree.c | 45 +++++++++++++++++++++++----------------
> > fs/xfs/libxfs/xfs_trans_resv.c | 16 ++++++++++++++
> > fs/xfs/libxfs/xfs_trans_space.h | 7 ++++++
> > 5 files changed, 85 insertions(+), 18 deletions(-)
>
> Looks good.
>
> Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
>
> > /* Calculate the refcount btree size for some records. */
> > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
> > index c879e7754ee6..6f83d9b306ee 100644
> > --- a/fs/xfs/libxfs/xfs_trans_resv.c
> > +++ b/fs/xfs/libxfs/xfs_trans_resv.c
> > @@ -814,6 +814,19 @@ xfs_trans_resv_calc(
> > struct xfs_mount *mp,
> > struct xfs_trans_resv *resp)
> > {
> > + unsigned int rmap_maxlevels = mp->m_rmap_maxlevels;
> > +
> > + /*
> > + * In the early days of rmap+reflink, we always set the rmap maxlevels
> > + * to 9 even if the AG was small enough that it would never grow to
> > + * that height. Transaction reservation sizes influence the minimum
> > + * log size calculation, which influences the size of the log that mkfs
> > + * creates. Use the old value here to ensure that newly formatted
> > + * small filesystems will mount on older kernels.
> > + */
> > + if (xfs_has_rmapbt(mp) && xfs_has_reflink(mp))
> > + mp->m_rmap_maxlevels = XFS_OLD_REFLINK_RMAP_MAXLEVELS;
> > +
>
> As an aside, what are your plans to get your "legacy minimum log
> size reservations" calculation patch moved upstream so we can stop
> having to care about this in future?
Hmm. I think I'm just going to bail on those until 5.17.
At this point I have the kmem_zone renaming series (already on the list)
and another patchset to shrink the defer items and convert them to use
slab caches that I might push after the kmem_zone thing if we get that
far.
--D
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx
