fs/dcache: export d_same_name() helper

Compare dentry name with case-exact name, return true if names
are same, or false.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/dcache.c

@@ -2247,10 +2247,16 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 }
 EXPORT_SYMBOL(d_add_ci);
 
-
-static inline bool d_same_name(const struct dentry *dentry,
-				const struct dentry *parent,
-				const struct qstr *name)
+/**
+ * d_same_name - compare dentry name with case-exact name
+ * @parent: parent dentry
+ * @dentry: the negative dentry that was passed to the parent's lookup func
+ * @name:   the case-exact name to be associated with the returned dentry
+ *
+ * Return: true if names are same, or false
+ */
+bool d_same_name(const struct dentry *dentry, const struct dentry *parent,
+		 const struct qstr *name)
 {
 	if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) {
 		if (dentry->d_name.len != name->len)
@@ -2261,6 +2267,7 @@ static inline bool d_same_name(const struct dentry *dentry,
 				       dentry->d_name.len, dentry->d_name.name,
 				       name) == 0;
 }
+EXPORT_SYMBOL_GPL(d_same_name);
 
 /**
  * __d_lookup_rcu - search for a dentry (racy, store-free)

include/linux/dcache.h

@@ -233,6 +233,8 @@ extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
 					wait_queue_head_t *);
 extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
 extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
+extern bool d_same_name(const struct dentry *dentry, const struct dentry *parent,
+			const struct qstr *name);
 extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
 extern struct dentry *d_find_any_alias(struct inode *inode);
 extern struct dentry * d_obtain_alias(struct inode *);