1 files changed, 22 insertions, 26 deletions

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index f241b9df642a..532bd7c46baf 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -842,7 +842,8 @@ int __printf(2, 3) debugfs_change_name(struct dentry *dentry, const char *fmt, .
 	int error = 0;
 	const char *new_name;
 	struct name_snapshot old_name;
-	struct dentry *parent, *target;
+	struct dentry *target;
+	struct renamedata rd = {};
 	struct inode *dir;
 	va_list ap;
 
@@ -855,36 +856,31 @@ int __printf(2, 3) debugfs_change_name(struct dentry *dentry, const char *fmt, .
 	if (!new_name)
 		return -ENOMEM;
 
-	parent = dget_parent(dentry);
-	dir = d_inode(parent);
-	inode_lock(dir);
+	rd.old_parent = dget_parent(dentry);
+	rd.new_parent = rd.old_parent;
+	rd.flags = RENAME_NOREPLACE;
+	target = lookup_noperm_unlocked(&QSTR(new_name), rd.new_parent);
+	if (IS_ERR(target))
+		return PTR_ERR(target);
 
-	take_dentry_name_snapshot(&old_name, dentry);
-
-	if (WARN_ON_ONCE(dentry->d_parent != parent)) {
-		error = -EINVAL;
-		goto out;
-	}
-	if (strcmp(old_name.name.name, new_name) == 0)
-		goto out;
-	target = lookup_noperm(&QSTR(new_name), parent);
-	if (IS_ERR(target)) {
-		error = PTR_ERR(target);
-		goto out;
-	}
-	if (d_really_is_positive(target)) {
-		dput(target);
-		error = -EINVAL;
+	error = start_renaming_two_dentries(&rd, dentry, target);
+	if (error) {
+		if (error == -EEXIST && target == dentry)
+			/* it isn't an error to rename a thing to itself */
+			error = 0;
 		goto out;
 	}
-	simple_rename_timestamp(dir, dentry, dir, target);
-	d_move(dentry, target);
-	dput(target);
+
+	dir = d_inode(rd.old_parent);
+	take_dentry_name_snapshot(&old_name, dentry);
+	simple_rename_timestamp(dir, dentry, dir, rd.new_dentry);
+	d_move(dentry, rd.new_dentry);
 	fsnotify_move(dir, dir, &old_name.name, d_is_dir(dentry), NULL, dentry);
-out:
 	release_dentry_name_snapshot(&old_name);
-	inode_unlock(dir);
-	dput(parent);
+	end_renaming(&rd);
+out:
+	dput(rd.old_parent);
+	dput(target);
 	kfree_const(new_name);
 	return error;
 }