diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index ee07162d35c7a2b260dacbf6e6897e5230335dd9..cce0e23b2454266f476f32366dbf19f73a6086c5 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -135,8 +135,17 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,
 		_leave(" = -ENAMETOOLONG");
 		return ERR_PTR(-ENAMETOOLONG);
 	}
-	if (namelen == 5 && memcmp(name, "@cell", 5) == 0)
+
+	/* Prohibit cell names that contain unprintable chars, '/' and '@' or
+	 * that begin with a dot.  This also precludes "@cell".
+	 */
+	if (name[0] == '.')
 		return ERR_PTR(-EINVAL);
+	for (i = 0; i < namelen; i++) {
+		char ch = name[i];
+		if (!isprint(ch) || ch == '/' || ch == '@')
+			return ERR_PTR(-EINVAL);
+	}
 
 	_enter("%*.*s,%s", namelen, namelen, name, vllist);