linux-ext4 - A question on directory checksums

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Date:   Sat, 22 Feb 2020 11:36:43 +0100 (CET)
From:   Bo Branten <bosse@....umu.se>
To:     linux-ext4@...r.kernel.org
Subject: A question on directory checksums

Hello,

I am implementing support for metadata checksums on an ext4 driver for 
another os and test this by writing something and then run e2fsck from 
Linux to see what it says. When I create a new empty directory that only 
contains . and .. I got this error message from e2fsck that I want to ask 
you to clearify:

bo@...desktop:~$ sudo e2fsck -pvf /dev/sdb2
/dev/sdb2: Directory inode 64, block #0, offset 0: directory has no checksum.
FIXED.

Am I right that it is not the checksum on the inode that represents the 
directory but the checksum in the directory entry tail in the first and 
only block?

Also do "no checksum" means something different than wrong checksum, like 
I have not initialized it correctly? (if I dont call 
initialize_dirent_tail I will get another error message from e2fsck that 
speficially says there is no room for the checksum so it can not be that)

Bo Branten