Re: [PATCH 12/14] xfs: compute actual maximum btree height for critical reservation calculation

Chandan Babu R
2021-09-20T10:12:16Z

On 18 Sep 2021 at 07:00, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Compute the actual maximum btree height when deciding if per-AG block
> reservation is critically low. This only affects the sanity check
> condition, since we /generally/ will trigger on the 10% threshold.
> This is a long-winded way of saying that we're removing one more
> usage of XFS_BTREE_MAXLEVELS.
>

Looks good.

Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>

> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
> fs/xfs/libxfs/xfs_ag_resv.c | 4 +++-
> fs/xfs/libxfs/xfs_btree.c | 19 +++++++++++++++----
> fs/xfs/libxfs/xfs_btree.h | 1 +
> 3 files changed, 19 insertions(+), 5 deletions(-)
>
>
> diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
> index 2aa2b3484c28..931481fbdd72 100644
> --- a/fs/xfs/libxfs/xfs_ag_resv.c
> +++ b/fs/xfs/libxfs/xfs_ag_resv.c
> @@ -72,6 +72,7 @@ xfs_ag_resv_critical(
> {
> xfs_extlen_t avail;
> xfs_extlen_t orig;
> + xfs_extlen_t btree_maxlevels;
>
> switch (type) {
> case XFS_AG_RESV_METADATA:
> @@ -91,7 +92,8 @@ xfs_ag_resv_critical(
> trace_xfs_ag_resv_critical(pag, type, avail);
>
> /* Critically low if less than 10% or max btree height remains. */
> - return XFS_TEST_ERROR(avail < orig / 10 || avail < XFS_BTREE_MAXLEVELS,
> + btree_maxlevels = xfs_btree_maxlevels(pag->pag_mount, XFS_BTNUM_MAX);
> + return XFS_TEST_ERROR(avail < orig / 10 || avail < btree_maxlevels,
> pag->pag_mount, XFS_ERRTAG_AG_RESV_CRITICAL);
> }
>
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index f9516828a847..6cf49f7e1299 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
> @@ -4922,12 +4922,17 @@ xfs_btree_has_more_records(
> return block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK);
> }
>
> -/* Compute the maximum allowed height for a given btree type. */
> -static unsigned int
> +/*
> + * Compute the maximum allowed height for a given btree type. If XFS_BTNUM_MAX
> + * is passed in, the maximum allowed height for all btree types is returned.
> + */
> +unsigned int
> xfs_btree_maxlevels(
> struct xfs_mount *mp,
> xfs_btnum_t btnum)
> {
> + unsigned int ret;
> +
> switch (btnum) {
> case XFS_BTNUM_BNO:
> case XFS_BTNUM_CNT:
> @@ -4943,9 +4948,15 @@ xfs_btree_maxlevels(
> case XFS_BTNUM_REFC:
> return mp->m_refc_maxlevels;
> default:
> - ASSERT(0);
> - return XFS_BTREE_MAXLEVELS;
> + break;
> }
> +
> + ret = mp->m_ag_maxlevels;
> + ret = max(ret, mp->m_bm_maxlevels[XFS_DATA_FORK]);
> + ret = max(ret, mp->m_bm_maxlevels[XFS_ATTR_FORK]);
> + ret = max(ret, M_IGEO(mp)->inobt_maxlevels);
> + ret = max(ret, mp->m_rmap_maxlevels);
> + return max(ret, mp->m_refc_maxlevels);
> }
>
> /* Allocate a new btree cursor of the appropriate size. */
> diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> index ae83fbf58c18..106760c540c7 100644
> --- a/fs/xfs/libxfs/xfs_btree.h
> +++ b/fs/xfs/libxfs/xfs_btree.h
> @@ -574,5 +574,6 @@ void xfs_btree_copy_keys(struct xfs_btree_cur *cur,
> const union xfs_btree_key *src_key, int numkeys);
> struct xfs_btree_cur *xfs_btree_alloc_cursor(struct xfs_mount *mp,
> struct xfs_trans *tp, xfs_btnum_t btnum);
> +unsigned int xfs_btree_maxlevels(struct xfs_mount *mp, xfs_btnum_t btnum);
>
> #endif /* __XFS_BTREE_H__ */

--
chandan