ext4: annotate struct fname with __counted_by()

Add the __counted_by compiler attribute to the flexible array member
name to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.

Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Thorsten Blum <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>

Author: toblux

fs/ext4/dir.c

@@ -418,7 +418,7 @@ struct fname {
 	__u32		inode;
 	__u8		name_len;
 	__u8		file_type;
-	char		name[];
+	char		name[] __counted_by(name_len);
 };
 
 /*