I also have commented a possible bug in existing ext2 code, marked with XXX.

Cc: linux-ext4@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>