On Do, 01.03.18 14:44, Hongzhi, Song (hongzhi.s...@windriver.com) wrote: > Thank you very much. It dose work. > > Would you tell me that how the '--no-block' works,
"systemd-mount" talks to systemd (i.e. PID 1) to issue mount/automount operations. By default it will do so synchronously, thus blocking until the mount is established. If you specify "--no-block" then you turn off this synchronous behaviour, and instead request asynchronous behaviour, where the rule will just request the operation to be executed, but won't wait for it to finish. When you invoke "systemd-mount" from a udev rule then using "--no-block" is a necessity to avoid a deadlock. That's because PID 1 won't operate on a device to mount before udev reported it to be fully availabled and probed. Now, if synchronously wait for that from inside the udev rule you hence delay precisely that probing forever. > I doesn't deeply understand the interpretation in > > https://www.freedesktop.org/software/systemd/man/systemd-mount.html#SYSTEMD_MOUNT_OPTIONS= > > > And why systemd-mount can solve the problem brought by MountFlag=slave. systemd-mount request the mount operation to be executed by PID 1, and hence outside of the mount context of udev. Lennart -- Lennart Poettering, Red Hat _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel