umount.cifs doesn't remove entry from /etc/mtab

[Chow Loong Jin]

Binary package hint: smbfs

I think it can be best summarized by the following console output:

hyperair@Hyperair-PC:~/test$ mount.cifs //localhost/Videos ./mnt
Password:
hyperair@Hyperair-PC:~/test$ mount
/dev/sda1 on / type ext3 (rw,noatime,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
/sys on /sys type sysfs (rw,noexec,nosuid,nodev)
varrun on /var/run type tmpfs (rw,noexec,nosuid,nodev,mode=0755)
varlock on /var/lock type tmpfs (rw,noexec,nosuid,nodev,mode=1777)
udev on /dev type tmpfs (rw,mode=0755)
devshm on /dev/shm type tmpfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
lrm on /lib/modules/2.6.22-14-generic/volatile type tmpfs (rw)
/dev/sdc1 on /home type ext3 (rw,noatime)
/dev/sdb1 on /home/hyperair/Music type ext3 (rw,noatime)
/dev/sda3 on /home/hyperair/Videos type ext3 (rw,noatime)
securityfs on /sys/kernel/security type securityfs (rw)
rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
//localhost/Videos on /home/hyperair/test/mnt type cifs (rw,mand,nosuid,nodev,user=hyperair)
hyperair@Hyperair-PC:~/test$ umount.cifs ./mnt
hyperair@Hyperair-PC:~/test$ mount
/dev/sda1 on / type ext3 (rw,noatime,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
/sys on /sys type sysfs (rw,noexec,nosuid,nodev)
varrun on /var/run type tmpfs (rw,noexec,nosuid,nodev,mode=0755)
varlock on /var/lock type tmpfs (rw,noexec,nosuid,nodev,mode=1777)
udev on /dev type tmpfs (rw,mode=0755)
devshm on /dev/shm type tmpfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
lrm on /lib/modules/2.6.22-14-generic/volatile type tmpfs (rw)
/dev/sdc1 on /home type ext3 (rw,noatime)
/dev/sdb1 on /home/hyperair/Music type ext3 (rw,noatime)
/dev/sda3 on /home/hyperair/Videos type ext3 (rw,noatime)
securityfs on /sys/kernel/security type securityfs (rw)
rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
//localhost/Videos on /home/hyperair/test/mnt type cifs (rw,mand,nosuid,nodev,user=hyperair)
hyperair@Hyperair-PC:~/test$

Any subsequent mounts and unmounts using mount.cifs and umount.cifs on the same directory will cause more entries to be deposited in /etc/mtab, and none of them will be removed short of using umount as root.

[Chuck Short (zulcss)]

Hello,

Thanks for the bug report. What does /proc/mounts say after going through this process?

Thanks
chuck

[Chow Loong Jin (hyperair)]

/proc/mounts works as expected. It's just /etc/mtab isn't updated accordingly.

[Chuck Short (zulcss)]

Hi,

Thanks for the information is this under hardy or a previous release. If its not hardy could you please download the iso and please test?

Thanks
chuck

[Chow Loong Jin (hyperair)]

It occurs on Hardy.

[Steve Langasek (vorlon)]

This appears to be a variant on a bug fixed in samba 3.0.25b-2:

  * cifs-umount-trailing-slashes.patch: canonicalize mount point names when
    umount.cifs is called, to avoid unnecessarily leaving entries behind in
    /etc/mtab if invoked with a trailing slash in the mount point name

Even with that fix, umount.cifs assumes that you will unmount using an absolute path rather than a relative path.

hyperair, as a workaround I recommend that you use the absolute path when unmounting cifs shares, until this can be resolved.

[Chow Loong Jin (hyperair)]

Alright, thanks for the tip.

[mehturt (mehturt)]

This problem still appears in 8.10.
There's a bug at samba's bugzilla about it https://bugzilla.samba.org/show_bug.cgi?id=4370 .

[Alex G (ogxela-yahoo)]

I can confirm this occurs when there is a symlink in the mountpoint path as well, in Hardy with the latest updates.

alex@fuzzy:/home/SODAPOP$ ls -l
total 104K
lrwxrwxrwx 1 root root 23 2009-01-07 10:15 agottschalk -> ../AUTOHOME/agottschalk/

alex@fuzzy:~/scripts$ mount.cifs //grapeape/Users/AGottschalk /home/AUTOHOME/alex/winhome
Password:

alex@fuzzy:~/scripts$ cat /etc/mtab
[...]
automount(pid5177) /home/AUTOHOME autofs rw,fd=4,pgrp=5177,minproto=2,maxproto=4 0 0
//grapeape/Users /home/AUTOHOME/alex/winhome cifs rw,mand,nosuid,nodev,user=alex 0 0

alex@fuzzy:~/scripts$ umount.cifs /home/AUTOHOME/alex/winhome

alex@fuzzy:~/scripts$ cat /etc/mtab
[...]
automount(pid5177) /home/AUTOHOME autofs rw,fd=4,pgrp=5177,minproto=2,maxproto=4 0 0
peaches:/srv/autohomes/alex /home/AUTOHOME/alex nfs rw,nosuid,soft,addr=10.10.1.31 0 0

alex@fuzzy:~/scripts$ mount.cifs //grapeape/Users/AGottschalk /home/SODAPOP/alex/winhome
Password:

alex@fuzzy:~/scripts$ umount.cifs /home/SODAPOP/alex/winhome

alex@fuzzy:~/scripts$ cat /etc/mtab
[...]
automount(pid5177) /home/AUTOHOME autofs rw,fd=4,pgrp=5177,minproto=2,maxproto=4 0 0
peaches:/srv/autohomes/alex /home/AUTOHOME/alex nfs rw,nosuid,soft,addr=10.10.1.31 0 0
//grapeape/Users /home/AUTOHOME/alex/winhome cifs rw,mand,nosuid,nodev,user=alex 0 0

[Thierry Carrez (ttx)]

Fixed in 3.2.9 and 3.3.2, so this should be fixed in Jaunty release.

[P.Constantine (pconstantine)]

??
Maverick

$ sudo mount -o username=user,workgroup=company,umask=000,iocharset=utf8,uid=user,gid=user //netapp/public /media/public/

$ sudo umount /media/public

$ cat /etc/mtab | grep public
//netapp/public/ /media/public cifs rw,mand 0 0

Regression? Was never fixed in the first place?

I've tried it now and then since 7.04 and EACH time it was 100% reproducible.

[P.Constantine (pconstantine)]

Let's see, strace on umount gives us this:

2969 fstat64(3, {st_mode=S_IFREG|0644, st_size=754, ...}) = 0
2969 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb775f000
2969 read(3, "/dev/sda1 / ext3 rw,errors=remou"..., 4096) = 754
2969 read(3, "", 4096) = 0
2969 close(3) = 0
2969 munmap(0xb775f000, 4096) = 0
2969 stat64("/sbin/umount.cifs", 0xbfdaeb60) = -1 ENOENT (No such file or directory)
2969 oldumount("/media/public" <<<<--- it hangs here!

Let's see:

$ dpkg --search `which mount.cifs`
cifs-utils: /sbin/mount.cifs

$ # dpkg -L cifs-utils
/.
/sbin
/sbin/mount.cifs
/usr
/usr/sbin
/usr/sbin/cifs.upcall
/usr/share
/usr/share/man
/usr/share/man/man8
/usr/share/man/man8/mount.cifs.8.gz
/usr/share/man/man8/cifs.upcall.8.gz
/usr/share/doc
/usr/share/doc/cifs-utils
/usr/share/doc/cifs-utils/copyright
/usr/share/doc/cifs-utils/NEWS.Debian.gz
/usr/share/doc/cifs-utils/changelog.gz
/usr/share/doc/cifs-utils/changelog.Debian.gz

$ dpkg -L smbfs
/.
/sbin
/sbin/mount.smbfs
/usr
/usr/share
/usr/share/doc
/usr/share/doc/smbfs
/usr/share/doc/smbfs/copyright
/usr/share/doc/smbfs/changelog.gz
/usr/share/doc/smbfs/changelog.Debian.gz
/usr/share/man
/usr/share/man/man8
/usr/bin
/usr/share/man/man8/mount.smbfs.8.gz
/usr/share/man/man8/smbmount.8.gz
/usr/bin/smbmount

As you can see 'umount.cifs' is indeed nowhere to be found.

[P.Constantine (pconstantine)]

Aha, it does unmount correctly after a lot of time inside oldumount()
This never happens when mounting with no trailing slash.