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