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?
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
