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),