f2fs: sync f2fs_lookup() with ext4_lookup()

As for ext4, now that fscrypt_has_permitted_context() correctly handles
the case where we have the key for the parent directory but not the
child, f2fs_lookup() no longer has to work around it.  Also add the same
warning message that ext4 uses.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/f2fs/namei.c

@@ -324,9 +324,10 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 	if (f2fs_encrypted_inode(dir) &&
 	    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
 	    !fscrypt_has_permitted_context(dir, inode)) {
-		bool nokey = f2fs_encrypted_inode(inode) &&
-			!fscrypt_has_encryption_key(inode);
-		err = nokey ? -ENOKEY : -EPERM;
+		f2fs_msg(inode->i_sb, KERN_WARNING,
+			 "Inconsistent encryption contexts: %lu/%lu",
+			 dir->i_ino, inode->i_ino);
+		err = -EPERM;
 		goto err_out;
 	}
 	return d_splice_alias(inode, dentry);