我最近将我的物理服务器从基于 14.04.4 upstart 的系统升级到基于 16.04.1 systemd 的系统，发现启动后根文件系统以只读方式挂载。dmesg 显示了以下在我看来可能的根本原因：
[ 6.994280] EXT4-fs (sda1): mounting ext3 file system using the ext4 subsystem
[ 7.020103] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts:(null)
[ 9.444360] systemd[1]: systemd 229 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN)
[ 9.449201] systemd[1]: Detected architecture x86.
[ 9.506555] systemd[1]: Set hostname to <bigdawg>.
[ 13.069691] systemd-sysv-generator[1153]: Unknown unit type for unit 'systemd-journald-dev-log.socket'
[ 14.647188] systemd[1]: local-fs-pre.target: Found ordering cycle on local-fs-pre.target/start
[ 14.649431] systemd[1]: local-fs-pre.target: Found dependency on systemd-remount-fs.service/start
[ 14.651511] systemd[1]: local-fs-pre.target: Found dependency on scsitools-pre.service/start
[ 14.653509] systemd[1]: local-fs-pre.target: Found dependency on readahead-desktop.service/start
[ 14.655433] systemd[1]: local-fs-pre.target: Found dependency on ebtables.service/start
[ 14.657310] systemd[1]: local-fs-pre.target: Found dependency on local-fs.target/start
[ 14.659141] systemd[1]: local-fs-pre.target: Found dependency on local-fs-pre.target/start
[ 14.660924] systemd[1]: local-fs-pre.target: Breaking ordering cycle by deleting job systemd-remount-fs.service/start
[ 14.662698] systemd[1]: systemd-remount-fs.service: Job systemd-remount-fs.service/start deleted to break ordering cycle starting with local-fs-pre.target/start
我已经使用 smartctl 长测试检查了媒体，一切似乎都很好。
我调试这个问题的下一步是什么？