В Thu, 28 Aug 2014 00:31:49 +0300 Mantas Mikulėnas <graw...@gmail.com> пишет:
> On Aug 27, 2014 10:03 PM, "Dale R. Worley" <wor...@alum.mit.edu> wrote: > > > > > From: Thomas Suckow <thomas.suc...@pnnl.gov> > > > > > > >> From: Lennart Poettering <lenn...@poettering.net> > > > > > > > >> Note that a concept of "mount at boot if it is there, otherwise > don't" > > > >> cannot work. > > > > > > > > It worked until a week or two ago. I want it back. > > > > > > > > I'm sure you're right that in the abstract, it cannot be made to > > > > work. But that isn't the problem I'm facing. > > > > > > It seems that a workaround could be to not put the volume in fstab > > > and add a unit to the startup that would mount it if present. If you > > > wanted to mount it later, you could manually start the unit again. > > > > I'd rather adjust systemd and leave fstab stable than vice-versa. > > > > Here's an interesting fact: What systemd does (in this situation) > > isn't true automounting; rather it waits for the *first* time the > > device/volume becomes available, and then mounts it. Any later > > attachments of the volume do not cause mounting (until the next > > reboot). > > Well, that's how /etc/fstab always behaved, right? Anything in there is "automounted" just once, when system boots. Later you have to manually do it. > > But at this point, I only need to investigate the issue. The > > documentation I've managed to find about systemd is rather abstract, > > there's no map between specific bits of functionality and the files > > that control them. > > > > My understanding is that everything systemd does is controlled by > > "units". In this case, entries in fstab cause the creation of units > > based on a "template". If you could point me to the template file in > > question, it would probably point me to all of the things I need to > > investigate. > > For fstab, the units are created by a 'generator' > (systemd-fstab-generator), which writes them under /run/systemd/generator > every time the configuration is reloaded. > > I'm not at my PC right now so I cannot check, but I /do/ remember someone > mentioning that if a fstab entry has the 'auto' option, then the generator > also symlinks the corresponding .mount unit under <devpath>.device.wants/ > (e.g. dev-sda3.device.wants/mnt-backup.mount), causing the .mount unit to > be triggered *every* time that device appears on the system. > > That is, in addition to local-fs.target triggering foo.mount and waiting > for bar.device one time only (as you describe), it makes bar.device itself > trigger foo.mount every time as well. > Hmm ... I'm not sure where this dependency comes from, but yes, it is there Requires=systemd-fsck@dev-sda1.service -.mount Wants=system.slice RequiredBy=local-fs.target systemd-sysctl.service WantedBy=dev-sda1.device Before=local-fs.target systemd-sysctl.service umount.target After=systemd-journald.socket dev-sda1.device systemd-fsck@dev-sda1.service local-fs-pre.target system.slice -.mount This looks like one of those implicit dependencies that are not documented anywhere ... _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
