> On 12/09/17 21:17, Badics, Alex wrote: >> Hi, >> >> We've been trying out autofs with both systemd-automount and the >> autofs userspace daemon, and it seems like it incorrectly marks a >> mountpoint as "expired" even though it's still in use in a different >> mount namespace. Am I doing something wrong? Are mount namespaces >> supported by the autofs driver? > > There are challenges with namespaces that I'm unable to resolve. > > The specific behavior your seeing is one of those problems. > > I'm unable to find a way to check propogated mounts. > > I tried recently and could only come up with a method that was > order n squared cost with the number of mounts which was, as you > would expect, rejected upstream. > > And what kernel version are you using? We tried with the latest stable (4.13.1), the latest Arch one (4.12.10), and the Xenial one (4.4.0) > >> >> Reproduction: >> /etc/autofs/auto.master: >> /mnt/test /etc/autofs/auto.test.nfs --timeout 10 >> >> /etc/autofs/auto.test.nfs: >> test -rw,soft,intr server.domain:/exports/nfs >> >> On one tab, I start autofs: >> # automount -f -v >> >> On another, I unshare a namespace, and cd into the test directory: >> # cd /mnt >> # unshare -m --propagation shared >> # cd test/test >> >> And just wait. The mount correctly happens, but after 10 seconds, the >> autofs daemon gets an expired message and tries to umount hte nfs >> mount, and fails, because it's busy. It retries until I cd out of the >> nfs directory, then it of course succeeds: >> >> Starting automounter version 5.1.3, master map auto.master >> using kernel protocol version 5.02 >> mounted indirect on /mnt/test with timeout 10, freq 3 seconds >> attempting to mount entry /mnt/test/test >> mounted /mnt/test/test >> 1 remaining in /mnt/test >> 1 remaining in /mnt/test >> 1 remaining in /mnt/test >> expiring path /mnt/test/test >>>> umount.nfs4: /mnt/test/test: device is busy >>>> umount.nfs4: /mnt/test/test: device is busy >>>> umount.nfs4: /mnt/test/test: device is busy >> Unable to update the mtab file, /proc/mounts and /etc/mtab will differ >> expired /mnt/test/test >> 1 remaining in /mnt/test >> 1 remaining in /mnt/test >> 1 remaining in /mnt/test >> 1 remaining in /mnt/test >> expiring path /mnt/test/test >> expired /mnt/test/test > > What is it your trying to do? > How would you like this to behave? We are trying to mount network shares under a container after it was started, and umount it when the container no longer uses it. /mnt is mounted with shared (or slave, we haven't decided on that yet) propagation, so simple mounts and umounts work fine. The container does no mount/umount calls whatsoever. What I found (in my limited research) is that may_umount_tree() is not namespace-aware, but may_umount is. I thought these should be semantically the same (one umount a mountpoint IFF she can umount everything under it), but I guess there are minor differences? > > Keep in mind that a mount namespace is little more than a view of > the set of current mounts so there is limited mount independence > possible. > > Ian -- To unsubscribe from this list: send the line "unsubscribe autofs" in
