Nah, systemd doesn't mount things twice. Most likely this happens simply because /etc/mtab is not being linked to /proc/mounts. We don't really support that anymore. You basically see an incorrect mtab intermixing the info from the current boot with some remains of the previous boot.

Could you verify that this problem goes away if you link /etc/mtab to /proc/mounts? If so then I'll reassign this to u-l-ng so that Karel makes sure that /etc/mtab is replaced by a symlink to /proc/mounts on package upgrades.

OK.

I did:


[root@tlondon etc]# ln -s /proc/mounts /etc/mtab
[root@tlondon etc]# ls -l /etc/mtab
lrwxrwxrwx. 1 root root 12 Nov 21 15:51 /etc/mtab -> /proc/mounts
[root@tlondon etc]# mount
rootfs on / type rootfs (rw)
/proc on /proc type proc (rw,relatime)
/sys on /sys type sysfs (rw,seclabel,relatime)
udev on /dev type devtmpfs (rw,seclabel,nosuid,relatime,size=1964796k,nr_inodes=491199,mode=755)
devpts on /dev/pts type devpts (rw,seclabel,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /dev/shm type tmpfs (rw,seclabel,relatime)
/dev/mapper/vg_tlondon-lv_root on / type ext4 (rw,seclabel,relatime,barrier=1,data=ordered)
none on /selinux type selinuxfs (rw,relatime)
udev on /dev type devtmpfs (rw,seclabel,nosuid,relatime,size=1964796k,nr_inodes=491199,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (rw,seclabel,nosuid,nodev,noexec,relatime,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/ns type cgroup (rw,nosuid,nodev,noexec,relatime,ns)
cgroup on /sys/fs/cgroup/cpu type cgroup (rw,nosuid,nodev,noexec,relatime,cpu)
cgroup on /sys/fs/cgroup/cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/net_cls type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
systemd-1 on /dev/mqueue type autofs (rw,relatime,fd=26,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
systemd-1 on /sys/kernel/debug type autofs (rw,relatime,fd=27,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
systemd-1 on /dev/hugepages type autofs (rw,relatime,fd=28,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
systemd-1 on /sys/kernel/security type autofs (rw,relatime,fd=29,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=31,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,seclabel,relatime)
mqueue on /dev/mqueue type mqueue (rw,seclabel,relatime)
/dev/sda1 on /boot type ext4 (rw,seclabel,relatime,barrier=1,data=ordered)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
gvfs-fuse-daemon on /home/tbl/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,relatime,user_id=500,group_id=500)
/dev/mapper/udisks-luks-uuid-94a9d7d7-f819-4c2c-b735-81bb28db0426-uid500 on /media/Backup1TB type ext4 (rw,seclabel,nosuid,nodev,relatime,barrier=1,data=ordered)
[root@tlondon etc]# 

Is that what you expected?

I'll reboot and see if this is 'stable'.

Yeah, appears stable after reboot:

[root@tlondon ~]# ls -l /etc/mtab
lrwxrwxrwx. 1 root root 12 Nov 21 15:51 /etc/mtab -> /proc/mounts
[root@tlondon ~]# 
[root@tlondon ~]# mount
rootfs on / type rootfs (rw)
/proc on /proc type proc (rw,relatime)
/sys on /sys type sysfs (rw,seclabel,relatime)
udev on /dev type devtmpfs (rw,seclabel,nosuid,relatime,size=1964796k,nr_inodes=491199,mode=755)
devpts on /dev/pts type devpts (rw,seclabel,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /dev/shm type tmpfs (rw,seclabel,relatime)
/dev/mapper/vg_tlondon-lv_root on / type ext4 (rw,seclabel,relatime,barrier=1,data=ordered)
none on /selinux type selinuxfs (rw,relatime)
udev on /dev type devtmpfs (rw,seclabel,nosuid,relatime,size=1964796k,nr_inodes=491199,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (rw,seclabel,nosuid,nodev,noexec,relatime,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/ns type cgroup (rw,nosuid,nodev,noexec,relatime,ns)
cgroup on /sys/fs/cgroup/cpu type cgroup (rw,nosuid,nodev,noexec,relatime,cpu)
cgroup on /sys/fs/cgroup/cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/net_cls type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
systemd-1 on /dev/mqueue type autofs (rw,relatime,fd=26,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
systemd-1 on /sys/kernel/debug type autofs (rw,relatime,fd=27,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
systemd-1 on /dev/hugepages type autofs (rw,relatime,fd=28,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
systemd-1 on /sys/kernel/security type autofs (rw,relatime,fd=29,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=31,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,seclabel,relatime)
mqueue on /dev/mqueue type mqueue (rw,seclabel,relatime)
/dev/sda1 on /boot type ext4 (rw,seclabel,relatime,barrier=1,data=ordered)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
gvfs-fuse-daemon on /home/tbl/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,relatime,user_id=500,group_id=500)
[root@tlondon ~]#

Yupp. looks good.

Ok, will reassign this to u-l-ng now.

Karel, please please please, make u-l-ng install a symlink in place of /etc/mtab by default! (and of course, make sure that the meta information stored in mtab beyond /proc/mounts isn't lost...)

(In reply to comment #4)
> Yupp. looks good.

Lennart, I don't understand why /etc/mtab contains the duplicate lines. 

(The symlink to /proc/mounts is bugfix/workaround, but it does not explain the problem.;-)

> Karel, please please please, make u-l-ng install a symlink in place of
> /etc/mtab by default! (and of course, make sure that the meta information
> stored in mtab beyond /proc/mounts isn't lost...)

Is it required for F-15?

In systemd we are not clearing /etc/mtab on boot. We are also not playing catchup with the status quo after /etc became writable. That means that /etc/mtab will collect old out-dated information from previous boots, and not contain information about the stuff we mount before /etc is rw.

Instead we actually added some code to systemd which warns in kmsg if /etc/mtab is still a real file. Basically, we are gently putting some pressure on you to get rid of mtab... ;-)

Yes, please fix this for F-15. I don't want to have to add this horrible code to systemd which resets and syncs mtab on boot.

Please please please with cream on top!

Just symlinking mtab to /proc/mounts will break (u)mount.crypt from pam_mount, because there is afaik no way to specify the entry for the filesystem column if a filesystem in /proc/mounts. E.g. if an ext4 filesystem on a luks encrypted volume is mounted with mount.crypt, /proc/mounts will say that it is ext3 instead of crypt, which is what is written to /etc/mtab. Therefore with the symlink umount won't call umount.crypt and therefore not close the luks volume.

*** Bug 668718 has been marked as a duplicate of this bug. ***

The problem with duplicate entries in mtab should be already resolved (by the symlink). The problem with mount.crypt and mount.nfs will be resolved by upstream(s). So, closing this bug.