This problem is not limited to stale mounts. It's an error in the interaction between mount, umount and mount details in /proc/mounts vs /etc/mtab
In /etc/mtab, nfs4 mounts seem to have a problem with leading slashes. For example, on my 12.04 client machine, mounting a zfs volume on a 12.04 host, the following works fine: me@client:/$ sudo mount -t nfs bighost:/remotevol /mnt/target me@client:/$ sudo umount /mnt/target me@client:/$ No issues. However, the mount command will accept the volume spec without the leading slash and mount it: me@client:/$ sudo mount -t nfs bighost:remotevol /mnt/target me@client:/$ sudo umount /mnt/target /mnt/target was not found in /proc/mounts /mnt/target was not found in /proc/mounts me@client:/$ And the the remotevol is not unmounted. umount fails to identify the mounted volume in /proc/mounts because, when mounted without the leading slash, it is denoted differently between /proc/mounts and the entry in /etc/mtab me@client:/$ grep /mnt/target /etc/mtab bighost:remotevol /mnt/target nfs rw,vers=4,addr=192.168.1.19,clientaddr=192.168.1.128 0 0 me@client:/$ grep /mnt/target /proc/mounts bighost:/remotevol/ /mnt/target nfs4 rw,relatime,vers=4,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=192.168.1.128,minorversion=0,local_lock=none,addr=192.168.1.19 0 0 To fix at time of the error, edit mtab for the un-umountable volume and add a leading slash to the volume path specifier... then unmount and it will work. To prevent the error occurring, always specify volume paths with a leading slash on the command line or in fstab... Real fix... I guess mount should require a leading slash on the volume name, and it's a bug that it doesn't? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/974374 Title: Error on unmounting a NFSv4 share To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/974374/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
