Date:   Fri, 17 Dec 2021 16:24:56 +0100
From:   Lukas Czerner <lczerner@redhat.com>
To:     Heiner Kallweit <hkallweit1@gmail.com>
Cc:     linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: Problem with data=ordered ext4 mount option in linux-next
Message-ID: <20211217152456.l7b2mbefdkk64fkj@work>
References: <b5817114-8122-cf0e-ca8e-b5d1c9f43bc2@gmail.com>
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On Fri, Dec 17, 2021 at 04:11:32PM +0100, Heiner Kallweit wrote:
> On linux-next systemd-remount-fs complains about an invalid mount option
> here, resulting in a r/o root fs. After playing with the mount options
> it turned out that data=ordered causes the problem. linux-next from Dec
> 1st was ok, so it seems to be related to the new mount API patches.
> 
> At a first glance I saw no obvious problem, the following looks good.
> Maybe you have an idea where to look ..
> 
> static const struct constant_table ext4_param_data[] = {
> 	{"journal",	EXT4_MOUNT_JOURNAL_DATA},
> 	{"ordered",	EXT4_MOUNT_ORDERED_DATA},
> 	{"writeback",	EXT4_MOUNT_WRITEBACK_DATA},
> 	{}
> };
> 
> 	fsparam_enum	("data",		Opt_data, ext4_param_data),
> 

Thank you for the report!

The ext4 mount has been reworked to use the new mount api and the work
has been applied to linux-next couple of days ago so I definitelly
assume there is a bug in there that I've missed. I will be looking into
it.

Can you be a little bit more specific about how to reproduce the problem
as well as the error it generates in the logs ? Any other mount options
used simultaneously, non-default file system features, or mount options
stored within the superblock ?

Can you reproduce it outside of the systemd unit, say a script ?

Thanks!
-Lukas