ramfs: support O_TMPFILE

[akpm@linux-foundation.org: update inode_operations.tmpfile]

Link: http://lkml.kernel.org/r/20190206073349.GA15311@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index 3c2658c..9ebd17d 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -151,6 +151,18 @@ static int ramfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 	return error;
 }
 
+static int ramfs_tmpfile(struct user_namespace *mnt_userns,
+			 struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	struct inode *inode;
+
+	inode = ramfs_get_inode(dir->i_sb, dir, mode, 0);
+	if (!inode)
+		return -ENOSPC;
+	d_tmpfile(dentry, inode);
+	return 0;
+}
+
 static const struct inode_operations ramfs_dir_inode_operations = {
 	.create		= ramfs_create,
 	.lookup		= simple_lookup,
@@ -161,6 +173,7 @@ static const struct inode_operations ramfs_dir_inode_operations = {
 	.rmdir		= simple_rmdir,
 	.mknod		= ramfs_mknod,
 	.rename		= simple_rename,
+	.tmpfile	= ramfs_tmpfile,
 };
 
 /*