systemd-fsck@.service, systemd-fsck-root.service, systemd-fsck-usr.service, systemd-fsck — File system checker logic
systemd-fsck@.service |
systemd-fsck-root.service |
systemd-fsck-usr.service |
/usr/lib/systemd/systemd-fsck |
systemd-fsck@.service, systemd-fsck-root.service, and
systemd-fsck-usr.service are services responsible for file system checks. They are
instantiated for each device that is configured for file system checking.
systemd-fsck-root.service and systemd-fsck-usr.service are
responsible for file system checks on the root and /usr file system, respectively, but only if the root
filesystem was not checked in the initrd. systemd-fsck@.service is used for all
other file systems and for the root file system in the initrd.
These services are started at boot if passno in /etc/fstab
for the file system is set to a value greater than zero, but only if it is also configured to be
mounted at boot (i.e. without "noauto" option). The file system check for root is
performed before the other file systems. Other file systems may be checked in parallel, except when
they are on the same rotating disk.
systemd-fsck does not know any details
about specific filesystems, and simply executes file system
checkers specific to each filesystem type
(fsck.). These checkers will decide if
the filesystem should actually be checked based on the time since
last check, number of mounts, unclean unmount, etc.type
systemd-fsck-root.service and systemd-fsck-usr.service
will activate reboot.target if
fsck(8)
returns the "System
should reboot" condition, or emergency.target if fsck
returns the "Filesystem errors left uncorrected" condition.
systemd-fsck@.service will fail if
fsck(8)
returns either the "System should reboot"
or the "Filesystem errors left uncorrected" condition. For filesystems
listed in /etc/fstab without "nofail"
or "noauto" options, local-fs.target
will then activate emergency.target.
systemd-fsck understands these kernel command line parameters:
fsck.mode=¶One of "auto",
"force", "skip". Controls
the mode of operation. The default is "auto",
and ensures that file system checks are done when the file
system checker deems them necessary. "force"
unconditionally results in full file system checks.
"skip" skips any file system
checks.
fsck.repair=¶One of "preen",
"yes", "no". Controls the
mode of operation. The default is "preen",
and will automatically repair problems that can be safely
fixed. "yes" will answer yes to all
questions by fsck and "no" will answer no to
all questions.
systemd-fsck supports the service credentials logic as implemented by
ImportCredential=/LoadCredential=/SetCredential=
(see systemd.exec(5) for
details). The following credentials are used when passed in:
fsck.mode, fsck.repair¶The contents of the credentials are parsed as same as the kernel command line options with the same name. See above for more details.
Note that by default the systemd-fsck@.service,
systemd-fsck-root.service, and systemd-fsck-usr.service unit
files are set up to inherit both fsck.mode and fsck.repair
credentials from the service manager.