xfs: hoist the node iroot update code out of xfs_btree_new_iroot

In preparation for allowing records in an inode btree root, hoist the
code that copies keyptrs from an existing node root into a child block
to a separate function.  Note that the new function explicitly computes
the keys of the new child block and stores that in the root block; while
the bmap btree could rely on leaving the key alone, realtime rmap needs
to set the new high key.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

1 files changed, 74 insertions, 38 deletions

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index b6f4c222750d..9914092c034d 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -2901,6 +2901,77 @@ xfs_btree_iroot_realloc(
 }
 
 /*
+ * Move the keys and pointers from a root block to a separate block.
+ *
+ * Since the keyptr size does not change, all we have to do is increase the
+ * tree height, copy the keyptrs to the new internal node (cblock), shrink
+ * the root, and copy the pointers there.
+ */
+STATIC int
+xfs_btree_promote_node_iroot(
+	struct xfs_btree_cur	*cur,
+	struct xfs_btree_block	*block,
+	int			level,
+	struct xfs_buf		*cbp,
+	union xfs_btree_ptr	*cptr,
+	struct xfs_btree_block	*cblock)
+{
+	union xfs_btree_key	*ckp;
+	union xfs_btree_key	*kp;
+	union xfs_btree_ptr	*cpp;
+	union xfs_btree_ptr	*pp;
+	int			i;
+	int			error;
+	int			numrecs = xfs_btree_get_numrecs(block);
+
+	/*
+	 * Increase tree height, adjusting the root block level to match.
+	 * We cannot change the root btree node size until we've copied the
+	 * block contents to the new child block.
+	 */
+	be16_add_cpu(&block->bb_level, 1);
+	cur->bc_nlevels++;
+	cur->bc_ptrs[level + 1] = 1;
+
+	/*
+	 * Adjust the root btree record count, then copy the keys from the old
+	 * root to the new child block.
+	 */
+	xfs_btree_set_numrecs(block, 1);
+	kp = xfs_btree_key_addr(cur, 1, block);
+	ckp = xfs_btree_key_addr(cur, 1, cblock);
+	xfs_btree_copy_keys(cur, ckp, kp, numrecs);
+
+	/* Check the pointers and copy them to the new child block. */
+	pp = xfs_btree_ptr_addr(cur, 1, block);
+	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
+	for (i = 0; i < numrecs; i++) {
+		error = xfs_btree_debug_check_ptr(cur, pp, i, level);
+		if (error)
+			return error;
+	}
+	xfs_btree_copy_ptrs(cur, cpp, pp, numrecs);
+
+	/*
+	 * Set the first keyptr to point to the new child block, then shrink
+	 * the memory buffer for the root block.
+	 */
+	error = xfs_btree_debug_check_ptr(cur, cptr, 0, level);
+	if (error)
+		return error;
+	xfs_btree_copy_ptrs(cur, pp, cptr, 1);
+	xfs_btree_get_keys(cur, cblock, kp);
+	xfs_btree_iroot_realloc(cur, 1 - numrecs);
+
+	/* Attach the new block to the cursor and log it. */
+	xfs_btree_setbuf(cur, level, cbp);
+	xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
+	xfs_btree_log_keys(cur, cbp, 1, numrecs);
+	xfs_btree_log_ptrs(cur, cbp, 1, numrecs);
+	return 0;
+}
+
+/*
  * Copy the old inode root contents into a real block and make the
  * broot point to it.
  */
@@ -2913,14 +2984,10 @@ xfs_btree_new_iroot(
 	struct xfs_buf		*cbp;		/* buffer for cblock */
 	struct xfs_btree_block	*block;		/* btree block */
 	struct xfs_btree_block	*cblock;	/* child btree block */
-	union xfs_btree_key	*ckp;		/* child key pointer */
-	union xfs_btree_ptr	*cpp;		/* child ptr pointer */
-	union xfs_btree_key	*kp;		/* pointer to btree key */
-	union xfs_btree_ptr	*pp;		/* pointer to block addr */
+	union xfs_btree_ptr	*pp;
 	union xfs_btree_ptr	nptr;		/* new block addr */
 	int			level;		/* btree level */
 	int			error;		/* error return code */
-	int			i;		/* loop counter */
 
 	XFS_BTREE_STATS_INC(cur, newroot);
 
@@ -2958,42 +3025,11 @@ xfs_btree_new_iroot(
 			cblock->bb_u.s.bb_blkno = bno;
 	}
 
-	be16_add_cpu(&block->bb_level, 1);
-	xfs_btree_set_numrecs(block, 1);
-	cur->bc_nlevels++;
-	cur->bc_ptrs[level + 1] = 1;
-
-	kp = xfs_btree_key_addr(cur, 1, block);
-	ckp = xfs_btree_key_addr(cur, 1, cblock);
-	xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
-
-	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
-	for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
-		error = xfs_btree_debug_check_ptr(cur, pp, i, level);
-		if (error)
-			goto error0;
-	}
-
-	xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
-
-	error = xfs_btree_debug_check_ptr(cur, &nptr, 0, level);
+	error = xfs_btree_promote_node_iroot(cur, block, level, cbp, &nptr,
+			cblock);
 	if (error)
 		goto error0;
 
-	xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
-
-	xfs_btree_iroot_realloc(cur, 1 - xfs_btree_get_numrecs(cblock));
-
-	xfs_btree_setbuf(cur, level, cbp);
-
-	/*
-	 * Do all this logging at the end so that
-	 * the root is at the right level.
-	 */
-	xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
-	xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
-	xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
-
 	*logflags |=
 		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork);
 	*stat = 1;