On Sat, May 02, 2015 at 08:26:25PM +0300, Andrei Borzenkov wrote: > В Sat, 2 May 2015 13:16:59 -0400 > Zbigniew Jędrzejewski-Szmek <[email protected]> пишет: > > > 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 > > [email protected] "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 > > [email protected] 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 [email protected] 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 > > [email protected]. > > You probably should mention that it effectively reverts > 956eaf2b8d6c9999024705ddadc7393bc707de02. Aaah, thanks, I completely forgot about that. I'll add a note.
Zbyszek > > > > > 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 > > _______________________________________________ systemd-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/systemd-devel
