libfs: document simple_get_link()

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/libfs.c

@@ -1167,6 +1167,20 @@ simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
 }
 EXPORT_SYMBOL(simple_nosetlease);
 
+/**
+ * simple_get_link - generic helper to get the target of "fast" symlinks
+ * @dentry: not used here
+ * @inode: the symlink inode
+ * @done: not used here
+ *
+ * Generic helper for filesystems to use for symlink inodes where a pointer to
+ * the symlink target is stored in ->i_link.  NOTE: this isn't normally called,
+ * since as an optimization the path lookup code uses any non-NULL ->i_link
+ * directly, without calling ->get_link().  But ->get_link() still must be set,
+ * to mark the inode_operations as being for a symlink.
+ *
+ * Return: the symlink target
+ */
 const char *simple_get_link(struct dentry *dentry, struct inode *inode,
 			    struct delayed_call *done)
 {