Re: [PATCH v2 07/47] xfs: add function pointers for get/update keys to the btree

[Brian Foster <bfoster@redhat.com>]

On Thu, Jul 28, 2016 at 12:46:15PM -0700, Darrick J. Wong wrote:
> Add some function pointers to bc_ops to get the btree keys for
> leaf and node blocks, and to update parent keys of a block.
> Convert the _btree_updkey calls to use our new pointer, and
> modify the tree shape changing code to call the appropriate
> get_*_keys pointer instead of _btree_copy_keys because the
> overlapping btree has to calculate high key values.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_alloc_btree.c  |    4 +
>  fs/xfs/libxfs/xfs_bmap_btree.c   |    4 +
>  fs/xfs/libxfs/xfs_btree.c        |  164 +++++++++++++++++++++++---------------
>  fs/xfs/libxfs/xfs_btree.h        |   19 ++++
>  fs/xfs/libxfs/xfs_ialloc_btree.c |    8 ++
>  5 files changed, 135 insertions(+), 64 deletions(-)
> 
...
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index 8d8e362..405442d 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
...
> @@ -2146,11 +2194,10 @@ xfs_btree_lshift(
>  		 */
>  		cur->bc_ops->init_key_from_rec(&key,
>  			xfs_btree_rec_addr(cur, 1, right));
> -		rkp = &key;

Sorry, I should have been more clear. I think this entire hunk (the
above key initialization and comment) is effectively dead.

>  	}
>  
> -	/* Update the parent key values of right. */
> -	error = xfs_btree_updkey(cur, rkp, level + 1);
> +	/* Update the parent keys of the right block. */
> +	error = cur->bc_ops->update_keys(cur, level);
>  	if (error)
>  		goto error0;
>  
> @@ -2292,7 +2339,6 @@ xfs_btree_rshift(
>  		xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
>  
>  		cur->bc_ops->init_key_from_rec(&key, rrp);
> -		rkp = &key;

Same here. key isn't used beyond this.

I see that hch has some objections to the design here. FWIW, resolution
of that aside, and with the above fixes:

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  
>  		ASSERT(cur->bc_ops->recs_inorder(cur, rrp,
>  			xfs_btree_rec_addr(cur, 2, right)));
> @@ -2321,7 +2367,8 @@ xfs_btree_rshift(
>  	if (error)
>  		goto error1;
>  
> -	error = xfs_btree_updkey(tcur, rkp, level + 1);
> +	/* Update the parent keys of the right block. */
> +	error = cur->bc_ops->update_keys(tcur, level);
>  	if (error)
>  		goto error1;
>  
> @@ -2422,6 +2469,11 @@ __xfs_btree_split(
>  
>  	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
>  
> +	/* Adjust numrecs for the later get_*_keys() calls. */
> +	lrecs -= rrecs;
> +	xfs_btree_set_numrecs(left, lrecs);
> +	xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
> +
>  	/*
>  	 * Copy btree block entries from the left block over to the
>  	 * new block, the right. Update the right block and log the
> @@ -2447,14 +2499,15 @@ __xfs_btree_split(
>  		}
>  #endif
>  
> +		/* Copy the keys & pointers to the new block. */
>  		xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
>  		xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
>  
>  		xfs_btree_log_keys(cur, rbp, 1, rrecs);
>  		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
>  
> -		/* Grab the keys to the entries moved to the right block */
> -		xfs_btree_copy_keys(cur, key, rkp, 1);
> +		/* Stash the keys of the new block for later insertion. */
> +		cur->bc_ops->get_node_keys(cur, right, key);
>  	} else {
>  		/* It's a leaf.  Move records.  */
>  		union xfs_btree_rec	*lrp;	/* left record pointer */
> @@ -2463,27 +2516,23 @@ __xfs_btree_split(
>  		lrp = xfs_btree_rec_addr(cur, src_index, left);
>  		rrp = xfs_btree_rec_addr(cur, 1, right);
>  
> +		/* Copy records to the new block. */
>  		xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
>  		xfs_btree_log_recs(cur, rbp, 1, rrecs);
>  
> -		cur->bc_ops->init_key_from_rec(key,
> -			xfs_btree_rec_addr(cur, 1, right));
> +		/* Stash the keys of the new block for later insertion. */
> +		cur->bc_ops->get_leaf_keys(cur, right, key);
>  	}
>  
> -
>  	/*
>  	 * Find the left block number by looking in the buffer.
> -	 * Adjust numrecs, sibling pointers.
> +	 * Adjust sibling pointers.
>  	 */
>  	xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
>  	xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
>  	xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
>  	xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
>  
> -	lrecs -= rrecs;
> -	xfs_btree_set_numrecs(left, lrecs);
> -	xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
> -
>  	xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
>  	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
>  
> @@ -2802,6 +2851,7 @@ xfs_btree_new_root(
>  		bp = lbp;
>  		nptr = 2;
>  	}
> +
>  	/* Fill in the new block's btree header and log it. */
>  	xfs_btree_init_block_cur(cur, nbp, cur->bc_nlevels, 2);
>  	xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
> @@ -2810,19 +2860,24 @@ xfs_btree_new_root(
>  
>  	/* Fill in the key data in the new root. */
>  	if (xfs_btree_get_level(left) > 0) {
> -		xfs_btree_copy_keys(cur,
> -				xfs_btree_key_addr(cur, 1, new),
> -				xfs_btree_key_addr(cur, 1, left), 1);
> -		xfs_btree_copy_keys(cur,
> -				xfs_btree_key_addr(cur, 2, new),
> -				xfs_btree_key_addr(cur, 1, right), 1);
> +		/*
> +		 * Get the keys for the left block's keys and put them directly
> +		 * in the parent block.  Do the same for the right block.
> +		 */
> +		cur->bc_ops->get_node_keys(cur, left,
> +				xfs_btree_key_addr(cur, 1, new));
> +		cur->bc_ops->get_node_keys(cur, right,
> +				xfs_btree_key_addr(cur, 2, new));
>  	} else {
> -		cur->bc_ops->init_key_from_rec(
> -				xfs_btree_key_addr(cur, 1, new),
> -				xfs_btree_rec_addr(cur, 1, left));
> -		cur->bc_ops->init_key_from_rec(
> -				xfs_btree_key_addr(cur, 2, new),
> -				xfs_btree_rec_addr(cur, 1, right));
> +		/*
> +		 * Get the keys for the left block's records and put them
> +		 * directly in the parent block.  Do the same for the right
> +		 * block.
> +		 */
> +		cur->bc_ops->get_leaf_keys(cur, left,
> +			xfs_btree_key_addr(cur, 1, new));
> +		cur->bc_ops->get_leaf_keys(cur, right,
> +			xfs_btree_key_addr(cur, 2, new));
>  	}
>  	xfs_btree_log_keys(cur, nbp, 1, 2);
>  
> @@ -2858,7 +2913,7 @@ xfs_btree_make_block_unfull(
>  	int			*index,	/* new tree index */
>  	union xfs_btree_ptr	*nptr,	/* new btree ptr */
>  	struct xfs_btree_cur	**ncur,	/* new btree cursor */
> -	union xfs_btree_key	*key, /* key of new block */
> +	union xfs_btree_key	*key,	/* key of new block */
>  	int			*stat)
>  {
>  	int			error = 0;
> @@ -3086,8 +3141,8 @@ xfs_btree_insrec(
>  	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
>  
>  	/* If we inserted at the start of a block, update the parents' keys. */
> -	if (optr == 1) {
> -		error = xfs_btree_updkey(cur, key, level + 1);
> +	if (xfs_btree_needs_key_update(cur, optr)) {
> +		error = cur->bc_ops->update_keys(cur, level);
>  		if (error)
>  			goto error0;
>  	}
> @@ -3107,7 +3162,7 @@ xfs_btree_insrec(
>  	 */
>  	*ptrp = nptr;
>  	if (!xfs_btree_ptr_is_null(cur, &nptr)) {
> -		*key = nkey;
> +		xfs_btree_copy_keys(cur, key, &nkey, 1);
>  		*curp = ncur;
>  	}
>  
> @@ -3386,8 +3441,6 @@ xfs_btree_delrec(
>  	struct xfs_buf		*bp;		/* buffer for block */
>  	int			error;		/* error return value */
>  	int			i;		/* loop counter */
> -	union xfs_btree_key	key;		/* storage for keyp */
> -	union xfs_btree_key	*keyp = &key;	/* passed to the next level */
>  	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
>  	struct xfs_buf		*lbp;		/* left buffer pointer */
>  	struct xfs_btree_block	*left;		/* left btree block */
> @@ -3458,13 +3511,6 @@ xfs_btree_delrec(
>  			xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
>  			xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
>  		}
> -
> -		/*
> -		 * If it's the first record in the block, we'll need to pass a
> -		 * key up to the next level (updkey).
> -		 */
> -		if (ptr == 1)
> -			keyp = xfs_btree_key_addr(cur, 1, block);
>  	} else {
>  		/* It's a leaf. operate on records */
>  		if (ptr < numrecs) {
> @@ -3473,16 +3519,6 @@ xfs_btree_delrec(
>  				-1, numrecs - ptr);
>  			xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
>  		}
> -
> -		/*
> -		 * If it's the first record in the block, we'll need a key
> -		 * structure to pass up to the next level (updkey).
> -		 */
> -		if (ptr == 1) {
> -			cur->bc_ops->init_key_from_rec(&key,
> -					xfs_btree_rec_addr(cur, 1, block));
> -			keyp = &key;
> -		}
>  	}
>  
>  	/*
> @@ -3549,8 +3585,8 @@ xfs_btree_delrec(
>  	 * If we deleted the leftmost entry in the block, update the
>  	 * key values above us in the tree.
>  	 */
> -	if (ptr == 1) {
> -		error = xfs_btree_updkey(cur, keyp, level + 1);
> +	if (xfs_btree_needs_key_update(cur, ptr)) {
> +		error = cur->bc_ops->update_keys(cur, level);
>  		if (error)
>  			goto error0;
>  	}
> diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> index b4f3035..e097e60 100644
> --- a/fs/xfs/libxfs/xfs_btree.h
> +++ b/fs/xfs/libxfs/xfs_btree.h
> @@ -180,6 +180,19 @@ struct xfs_btree_ops {
>  				union xfs_btree_rec *r1,
>  				union xfs_btree_rec *r2);
>  #endif
> +
> +	/* derive the low & high keys from the records in a leaf block */
> +	void	(*get_leaf_keys)(struct xfs_btree_cur *cur,
> +				 struct xfs_btree_block *block,
> +				 union xfs_btree_key *key);
> +
> +	/* derive the low & high keys from the keys in a node block */
> +	void	(*get_node_keys)(struct xfs_btree_cur *cur,
> +				 struct xfs_btree_block *block,
> +				 union xfs_btree_key *key);
> +
> +	/* update the parent keys of given btree level */
> +	int	(*update_keys)(struct xfs_btree_cur *cur, int level);
>  };
>  
>  /*
> @@ -475,4 +488,10 @@ bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs);
>  uint xfs_btree_compute_maxlevels(struct xfs_mount *mp, uint *limits,
>  				 unsigned long len);
>  
> +void xfs_btree_get_leaf_keys(struct xfs_btree_cur *cur,
> +		struct xfs_btree_block *block, union xfs_btree_key *key);
> +void xfs_btree_get_node_keys(struct xfs_btree_cur *cur,
> +		struct xfs_btree_block *block, union xfs_btree_key *key);
> +int xfs_btree_update_keys(struct xfs_btree_cur *cur, int level);
> +
>  #endif	/* __XFS_BTREE_H__ */
> diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
> index 88da2ad..a48f448 100644
> --- a/fs/xfs/libxfs/xfs_ialloc_btree.c
> +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
> @@ -314,6 +314,10 @@ static const struct xfs_btree_ops xfs_inobt_ops = {
>  	.keys_inorder		= xfs_inobt_keys_inorder,
>  	.recs_inorder		= xfs_inobt_recs_inorder,
>  #endif
> +
> +	.get_leaf_keys		= xfs_btree_get_leaf_keys,
> +	.get_node_keys		= xfs_btree_get_node_keys,
> +	.update_keys		= xfs_btree_update_keys,
>  };
>  
>  static const struct xfs_btree_ops xfs_finobt_ops = {
> @@ -335,6 +339,10 @@ static const struct xfs_btree_ops xfs_finobt_ops = {
>  	.keys_inorder		= xfs_inobt_keys_inorder,
>  	.recs_inorder		= xfs_inobt_recs_inorder,
>  #endif
> +
> +	.get_leaf_keys		= xfs_btree_get_leaf_keys,
> +	.get_node_keys		= xfs_btree_get_node_keys,
> +	.update_keys		= xfs_btree_update_keys,
>  };
>  
>  /*
> 
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