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

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, Jul 26, 2016 at 03:09:54PM -0400, Brian Foster wrote:
> On Wed, Jul 20, 2016 at 09:56:46PM -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        |  159 +++++++++++++++++++++++---------------
> >  fs/xfs/libxfs/xfs_btree.h        |   19 +++++
> >  fs/xfs/libxfs/xfs_ialloc_btree.c |    8 ++
> >  5 files changed, 133 insertions(+), 61 deletions(-)
> > 
> > 
> ...
> > diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> > index 8d8e362..70d1c60 100644
> > --- a/fs/xfs/libxfs/xfs_btree.c
> > +++ b/fs/xfs/libxfs/xfs_btree.c
> ...
> > @@ -2149,8 +2197,8 @@ xfs_btree_lshift(
> >  		rkp = &key;
> >  	}
> >  
> > -	/* 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);
> 
> Looks like there's some code to set up rkp just above that can probably
> die.
> 
> >  	if (error)
> >  		goto error0;
> >  
> > @@ -2321,7 +2369,8 @@ 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);
> 
> Similar deal here, just a bit further up.

Yup, both rkp = &key instances can go.

> >  	if (error)
> >  		goto error1;
> >  
> > @@ -2422,6 +2471,10 @@ __xfs_btree_split(
> >  
> >  	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
> >  
> > +	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 +2500,15 @@ __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 */
> > @@ -2463,14 +2517,14 @@ __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.
> > @@ -2480,10 +2534,6 @@ __xfs_btree_split(
> >  	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);
> > -
> 
> The immediately previous comment needs an update if this gets moved.

I'll update the comment and add a new one at the new site explaining why the
numrecs update has to come first (the overlapped get_keys() functions need it).

> >  	xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
> >  	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
> >  
> ...
> > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> > index b4f3035..bb40457 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);
> >  };
> >  
> >  /*
> > @@ -474,5 +487,11 @@ bool xfs_btree_sblock_v5hdr_verify(struct xfs_buf *bp);
> >  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);
> > + 
> 
> Whitespace damage here ^

Oops.  Will fix, thanks for the review!

--D

> 
> Brian
> 
> > +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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