Re: Problem with data=ordered ext4 mount option in linux-next

[Heiner Kallweit <hkallweit1@gmail.com>]

On 17.12.2021 16:24, Lukas Czerner wrote:
> 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 ?
> 
Yes:

[root@zotac ~]# mount -o remount,data=ordered /
mount: /: mount point not mounted or bad option.
[root@zotac ~]# mount -o remount,discard /
[root@zotac ~]#

"systemctl status systemd-remount-fs" shows the same error.

Following options I had in my fstab (ext4 fs):
rw,relatime,data=ordered,discard

No non-default system features.

> Thanks!
> -Lukas
> 
Heiner