Re: [PATCH 10/14] xfs: encode the max btree height in the cursor

Chandan Babu R
2021-09-20T10:11:42Z

On 18 Sep 2021 at 07:00, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Encode the maximum btree height in the cursor, since we're soon going to
> allow smaller cursors for AG btrees and larger cursors for file btrees.
>

Looks good.

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

> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
> fs/xfs/libxfs/xfs_bmap.c | 2 +-
> fs/xfs/libxfs/xfs_btree.c | 5 +++--
> fs/xfs/libxfs/xfs_btree.h | 3 ++-
> fs/xfs/libxfs/xfs_btree_staging.c | 10 +++++-----
> 4 files changed, 11 insertions(+), 9 deletions(-)
>
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index 644b956301b6..2ae5bf9a74e7 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -239,7 +239,7 @@ xfs_bmap_get_bp(
> if (!cur)
> return NULL;
>
> - for (i = 0; i < XFS_BTREE_MAXLEVELS; i++) {
> + for (i = 0; i < cur->bc_maxlevels; i++) {
> if (!cur->bc_levels[i].bp)
> break;
> if (xfs_buf_daddr(cur->bc_levels[i].bp) == bno)
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index 70785004414e..2486ba22c01d 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
> @@ -2933,7 +2933,7 @@ xfs_btree_new_iroot(
> be16_add_cpu(&block->bb_level, 1);
> xfs_btree_set_numrecs(block, 1);
> cur->bc_nlevels++;
> - ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
> + ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
> cur->bc_levels[level + 1].ptr = 1;
>
> kp = xfs_btree_key_addr(cur, 1, block);
> @@ -3097,7 +3097,7 @@ xfs_btree_new_root(
> xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
> cur->bc_levels[cur->bc_nlevels].ptr = nptr;
> cur->bc_nlevels++;
> - ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
> + ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
> *stat = 1;
> return 0;
> error0:
> @@ -4941,6 +4941,7 @@ xfs_btree_alloc_cursor(
> cur->bc_mp = mp;
> cur->bc_btnum = btnum;
> cur->bc_blocklog = mp->m_sb.sb_blocklog;
> + cur->bc_maxlevels = XFS_BTREE_MAXLEVELS;
>
> return cur;
> }
> diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> index 6540c4957c36..6075918efa0c 100644
> --- a/fs/xfs/libxfs/xfs_btree.h
> +++ b/fs/xfs/libxfs/xfs_btree.h
> @@ -235,9 +235,10 @@ struct xfs_btree_cur
> struct xfs_mount *bc_mp; /* file system mount struct */
> const struct xfs_btree_ops *bc_ops;
> uint bc_flags; /* btree features - below */
> - union xfs_btree_irec bc_rec; /* current insert/search record value */
> + uint8_t bc_maxlevels; /* maximum levels for this btree type */
> uint8_t bc_nlevels; /* number of levels in the tree */
> uint8_t bc_blocklog; /* log2(blocksize) of btree blocks */
> + union xfs_btree_irec bc_rec; /* current insert/search record value */
> xfs_btnum_t bc_btnum; /* identifies which btree type */
> int bc_statoff; /* offset of btre stats array */
>
> diff --git a/fs/xfs/libxfs/xfs_btree_staging.c b/fs/xfs/libxfs/xfs_btree_staging.c
> index cc56efc2b90a..dd75e208b543 100644
> --- a/fs/xfs/libxfs/xfs_btree_staging.c
> +++ b/fs/xfs/libxfs/xfs_btree_staging.c
> @@ -657,12 +657,12 @@ xfs_btree_bload_compute_geometry(
> * checking levels 0 and 1 here, so set bc_nlevels such that the btree
> * code doesn't interpret either as the root level.
> */
> - cur->bc_nlevels = XFS_BTREE_MAXLEVELS - 1;
> + cur->bc_nlevels = cur->bc_maxlevels - 1;
> xfs_btree_bload_ensure_slack(cur, &bbl->leaf_slack, 0);
> xfs_btree_bload_ensure_slack(cur, &bbl->node_slack, 1);
>
> bbl->nr_records = nr_this_level = nr_records;
> - for (cur->bc_nlevels = 1; cur->bc_nlevels <= XFS_BTREE_MAXLEVELS;) {
> + for (cur->bc_nlevels = 1; cur->bc_nlevels <= cur->bc_maxlevels;) {
> uint64_t level_blocks;
> uint64_t dontcare64;
> unsigned int level = cur->bc_nlevels - 1;
> @@ -703,7 +703,7 @@ xfs_btree_bload_compute_geometry(
> * block-based btree level.
> */
> cur->bc_nlevels++;
> - ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
> + ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
> xfs_btree_bload_level_geometry(cur, bbl, level,
> nr_this_level, &avg_per_block,
> &level_blocks, &dontcare64);
> @@ -719,14 +719,14 @@ xfs_btree_bload_compute_geometry(
>
> /* Otherwise, we need another level of btree. */
> cur->bc_nlevels++;
> - ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
> + ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
> }
>
> nr_blocks += level_blocks;
> nr_this_level = level_blocks;
> }
>
> - if (cur->bc_nlevels > XFS_BTREE_MAXLEVELS)
> + if (cur->bc_nlevels > cur->bc_maxlevels)
> return -EOVERFLOW;
>
> bbl->btree_height = cur->bc_nlevels;

--
chandan