From: Christoph Hellwig <hch@lst.de>
Date: Thu, 9 Nov 2017 09:11:41 -0800
Subject: xfs: add some comments to xfs_iext_insert/xfs_iext_insert_node
Git-commit: fc258f4b8bb578c39223ff572b4dec8d56a2ed81
Patch-mainline: v4.15-rc1
References: bsc#1095344

Reported-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/xfs/libxfs/xfs_iext_tree.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_iext_tree.c b/fs/xfs/libxfs/xfs_iext_tree.c
index 85d7f708eafc..c28a24aca9c5 100644
--- a/fs/xfs/libxfs/xfs_iext_tree.c
+++ b/fs/xfs/libxfs/xfs_iext_tree.c
@@ -525,6 +525,10 @@ xfs_iext_insert_node(
 	if (nr_entries == KEYS_PER_NODE)
 		new = xfs_iext_split_node(&node, &pos, &nr_entries);
 
+	/*
+	 * Update the pointers in higher levels if the first entry changes
+	 * in an existing node.
+	 */
 	if (node != new && pos == 0 && nr_entries > 0)
 		xfs_iext_update_node(ifp, node->keys[0], offset, level, node);
 
@@ -643,6 +647,10 @@ xfs_iext_insert(
 	if (nr_entries == RECS_PER_LEAF)
 		new = xfs_iext_split_leaf(cur, &nr_entries);
 
+	/*
+	 * Update the pointers in higher levels if the first entry changes
+	 * in an existing node.
+	 */
 	if (cur->leaf != new && cur->pos == 0 && nr_entries > 0) {
 		xfs_iext_update_node(ifp, xfs_iext_leaf_key(cur->leaf, 0),
 				offset, 1, cur->leaf);