In the initramfs, we run systemd-fsck@<sysroot-device>.service. In the real system we run systemd-fsck-root.service. It is hard to pass the information that the latter should not run if the first succeeded using unit state only.
- in the real system, we need a synchronization point between the fsck for root and other fscks, to express the dependency to run this systemd-fsck@.service "before all other systemd-fsck@ units". We cannot express it directly, because there are no wildcard dependencies. We could use a target as a sychronization point, but then we would have to provide drop-ins to order systemd-fsck@-.service before the target, and all others after it, which becomes messy. The currently used alternative of having a special unit (systemd-fsck-root.service) makes it easy to express this dependency, and seems to be the best solution. - we cannot use systemd-fsck-root.service in the initramfs, because other fsck units should not be ordered after it. In the real system, the root device is always checked and mounted before other filesystems, but in the initramfs this doesn't have to be true: /sysroot might be stacked on other filesystems and devices. - the name of the root device can legitimately be specified in a different way in the initramfs (on the kernel command line, or automatically discovered through GPT), and in the real fs (in /etc/fstab). Even if we didn't need systemd-fsck-root.service as a synchronization point, it would be hard to ensure the same instance parameter is provided for systemd-fsck@.service in the initrams and the real system. Let's use a "side channel" to pass this information. /run/systemd/fsck-root-done is touched after fsck in the initramfs succeeds, through an ExecStartPost line in a drop-in for systemd-fsck@sysroot.service. https://bugzilla.redhat.com/show_bug.cgi?id=1201979 --- src/shared/generator.c | 7 +++++++ units/systemd-fsck-root.service.in | 1 + 2 files changed, 8 insertions(+) diff --git a/src/shared/generator.c b/src/shared/generator.c index 7b2f846175..a71222d1cb 100644 --- a/src/shared/generator.c +++ b/src/shared/generator.c @@ -78,6 +78,13 @@ int generator_write_fsck_deps( "RequiresOverridable=%1$s\n" "After=%1$s\n", fsck); + + if (in_initrd() && path_equal(where, "/sysroot")) + return write_drop_in_format(dir, fsck, 50, "stamp", + "# Automatically generated by %s\n\n" + "[Service]\n" + "ExecStartPost=-/bin/touch /run/systemd/fsck-root-done\n", + program_invocation_short_name); } return 0; diff --git a/units/systemd-fsck-root.service.in b/units/systemd-fsck-root.service.in index 3617abf04a..48dacc841c 100644 --- a/units/systemd-fsck-root.service.in +++ b/units/systemd-fsck-root.service.in @@ -11,6 +11,7 @@ Documentation=man:systemd-fsck-root.service(8) DefaultDependencies=no Before=local-fs.target shutdown.target ConditionPathIsReadWrite=!/ +ConditionPathExists=!/run/systemd/fsck-root-done [Service] Type=oneshot -- 2.3.5 _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
