On Sat, Jan 30, 2016 at 07:30:13PM -0800, Zoltan wrote:
> There is a problem in the code of util-linux-2.27.1, in the umount binary.
>
> The command
>
> umount -a -O _netdev
>
> does _not_ umount anything, despite an /etc/fstab with the likes of
>
> ...
> alpha:/var/mail /var/mail nfs _netdev,soft,tcp
> ...
>
> The "mount -a -O _netdev" command works as expected. However, the
> /run/mount/utab files is empty, and I was unable to get the "umount -a -O
> _netdev" to work as advertised. Running it with "--verbose" flag merely
> confirmed that everything was being ": ignored".
>
> I have a physical /etc/mtab (not symlink), and the "_netdev" option is missing
> from /etc/mtab file, but that's probably expected???
You need /etc/mtab *or* /run/mount/utab. It does not make sense to
have both files. Use 'rm -rf /run/mount' or use the symlink.
It's also important if you have /sbin/mount.nfs linked with libmount.
I guess it's system without systemd.
> If I manually add it (_netdev) to /etc/mtab, then the umount -a -O _netdev
> does work. But /run/mount/utab is empty. Trying to step through the code
It seems that the problem is not umount, but missing _netdev in mtab
or utab.
Suggestion:
* cleanup your disk (use the symlink or regular mtab)
* try "LIBMOUNT_DEBUG=all mount /var/mail" and verify that _netdev is
stored on the disk (mtab or utab)
* if success try "LIBMOUNT_DEBUG=all umount -a -O _netdev"
Note that for NFS we use mount.nfs from nfs-utils package and it has to
be compiled with libmount, otherwise it does not store anything to utab
and use mtab (if possible).
On systems with systemd we use --enable-libmount-force-mountinfo where
classic mtab is ignored at all.
The env.variable LIBMOUNT_DEBUG=all is your good friend if you want to
debug anything.
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
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