nilfs2: add kernel-doc comments to nilfs_btree_convert_and_insert()

This commit adds kernel-doc style comments with complete parameter
descriptions for the function nilfs_btree_convert_and_insert.

Link: https://lkml.kernel.org/r/20240410075629.3441-3-konishi.ryusuke@gmail.com
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Yang Li

fs/nilfs2/btree.c

@@ -1857,13 +1857,22 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *btree,
 }
 
 /**
- * nilfs_btree_convert_and_insert -
- * @bmap:
- * @key:
- * @ptr:
- * @keys:
- * @ptrs:
- * @n:
+ * nilfs_btree_convert_and_insert - Convert and insert entries into a B-tree
+ * @btree: NILFS B-tree structure
+ * @key: Key of the new entry to be inserted
+ * @ptr: Pointer (block number) associated with the key to be inserted
+ * @keys: Array of keys to be inserted in addition to @key
+ * @ptrs: Array of pointers associated with @keys
+ * @n: Number of keys and pointers in @keys and @ptrs
+ *
+ * This function is used to insert a new entry specified by @key and @ptr,
+ * along with additional entries specified by @keys and @ptrs arrays, into a
+ * NILFS B-tree.
+ * It prepares the necessary changes by allocating the required blocks and any
+ * necessary intermediate nodes. It converts configurations from other forms of
+ * block mapping (the one that currently exists is direct mapping) to a B-tree.
+ *
+ * Return: 0 on success or a negative error code on failure.
  */
 int nilfs_btree_convert_and_insert(struct nilfs_bmap *btree,
 				   __u64 key, __u64 ptr,