diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 39e3661a80c4..824d95c19564 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2374,18 +2374,19 @@ int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
 {
 	int index;
-	int depth;
 
 	/* If we are converting the inline data, only one is needed here. */
 	if (ext4_has_inline_data(inode))
 		return 1;
 
-	depth = ext_depth(inode);
-
+	/*
+	 * Extent tree can change between the time we estimate credits and
+	 * the time we actually modify the tree. Assume the worst case.
+	 */
 	if (extents <= 1)
-		index = depth * 2;
+		index = EXT4_MAX_EXTENT_DEPTH * 2;
 	else
-		index = depth * 3;
+		index = EXT4_MAX_EXTENT_DEPTH * 3;
 
 	return index;
 }