Cannot mount CIFS shares shared via ZFS

[atoponce]

I've discovered a bug with mounting Samba shares on Debian testing with up-to-date packages and using the 0.6.0-rc13 packages compiled from source. First, I installed the necessary Samba packages, created my ZFS dataset, and made it available to Samba:

# aptitude install -R samba samba-client samba-tools cifs-utils
# zfs create -o casesensitivity=mixed -o sharesmb=on pool/srv
# zfs share pool/srv

Using the Samba client, I can verify that it is available (assuming 'eightyeight' is my workstation):

# smbclient -U guest -NL eightyeight 2> /dev/null | grep Disk
      print$          Disk      Printer Drivers
      sysvol          Disk      
      netlogon        Disk      
      pool_srv        Disk      Comment: /srv

Yet, trying to mount it fails:

# mount -t cifs -o guest '//eightyeight/srv' /mnt
Retrying with upper case share name
mount error(6): No such device or address
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

Trying to access the share via the interactive Samba client without mounting also fails:

# smbclient -U guest -N //eightyeight/srv
Domain=[WORKGROUP] OS=[Unix] Server=[Samba 3.6.6]
tree connect failed: NT_STATUS_BAD_NETWORK_NAME

However, if I add the relevant config to /etc/samba/smb.conf and restart the Samba daemon, I can mount the share and browse it:

# awk 'NR>343' /etc/samba/smb.conf
[srv]
  read only = no
  browsable = yes
  guest ok = yes
  path = /srv
# mount -t cifs -o guest '//eightyeight/srv' /mnt
# ls /mnt
foo
# mount | grep srv
pool/srv on /srv type zfs (rw,relatime,xattr)
//eightyeight/srv on /mnt type cifs (rw,relatime,sec=ntlm,unc=\\eightyeight\srv,username=,uid=0,noforceuid,gid=0,noforcegid,addr=10.0.0.74,unix,posixpaths,serverino,acl,rsize=1048576,wsize=65536,actimeo=1)
# smbclient -U guest -N //eightyeight/srv
Domain=[WORKGROUP] OS=[Unix] Server=[Samba 3.6.6]
smb: \> ls
  .                                   D        0  Wed Dec 26 15:11:40 2012
  ..                                  D        0  Thu Dec 27 13:40:23 2012
  foo                                          4  Wed Dec 26 15:11:40 2012

                40812 blocks of size 4194304. 40812 blocks available

Relevant operating system info:

# dpkg -l 'zfs*' 'spl*'
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                                                  Version                         Architecture                    Description
+++-=====================================================-===============================-===============================-================================================================================================================
ii  spl                                                   0.6.0-1                         amd64                           SPL Utils
ii  spl-modules                                           0.6.0-1                         amd64                           Solaris Porting Layer Modules
ii  spl-modules-devel                                     0.6.0-1                         amd64                           Solaris Porting Layer Headers and Symbols
ii  zfs                                                   0.6.0-1                         amd64                           ZFS Library and Utils
ii  zfs-devel                                             0.6.0-1                         amd64                           ZFS File System User Headers
ii  zfs-dracut                                            0.6.0-1                         amd64                           ZFS Dracut Module
ii  zfs-modules                                           0.6.0-1                         amd64                           ZFS File System
ii  zfs-modules-devel                                     0.6.0-1                         amd64                           ZFS File System Headers and Symbols
ii  zfs-test                                              0.6.0-1                         amd64                           ZFS File System Test Infrastructure
# uname -a
Linux eightyeight 3.2.0-4-amd64 #1 SMP Debian 3.2.35-2 x86_64 GNU/Linux
# lsmod | awk '/zfs/ || /spl/'
zfs                   809810  10 
zunicode              324505  1 zfs
zavl                   13115  1 zfs
zcommon                35894  1 zfs
znvpair                31373  2 zcommon,zfs
spl                   124517  5 znvpair,zcommon,zavl,zunicode,zfs
zlib_deflate           25638  1 spl

I can provide straces or other debugging output as needed.

[ismell]

Is the path not //eightyeight/pool_srv ?

[atoponce]

No. The path is //eightyeight/srv. The "pool/srv" mountpoint is "/srv" on the box, not "/pool/srv". This can be verified:

# zfs get mountpoint pool/srv
NAME      PROPERTY    VALUE       SOURCE
pool/srv  mountpoint  /srv        local
# mount | grep srv
pool/srv on /srv type zfs (rw,relatime,xattr)

[aikudinov]

All it does is running "net usershare add" and since it is bad to just give
everyone access to your shares, it sets guest_ok=n. Check
/var/lib/samba/usershares.
You are trying to access share as a guest and it fails as expected. Also
share name should be pool_srv indeed.

I was looking at the code earlier trying to figure out how to rename share
(on solaris you can) and I think you can't set any options there yet.

[atoponce]

It won't share using standard authentication. Using guest is just a simple example. Also, as mentioned, I should not be sharing //eightyeight/pool/srv as the mountpoint is not '/pool/srv' but '/srv'. If that is what is expected, then that's another bug. Without ZFS, I can share //eightyeight/srv with no problem.

[FransUrbo]

the mountpoint is not '/pool/srv' but '/srv'.

Why is this a bug?

[atoponce]

Having pool/srv mounted to /srv is not a bug. Using a Samba client to mount /pool/srv/ when it does not exist, is.

[aikudinov]

Look, you run smbclient -U guest -NL eightyeight 2> /dev/null | grep Disk
and getting pool_srv Disk Comment: /srv

Then you are doing smbclient -U guest -N //eightyeight/srv
When you should run smbclient -U guest -N //eightyeight/pool_srv

You are confused, ZoL just picks dataset name, replaces slashes with underscores and uses it as share name, NOT the mountpoint!

[FransUrbo]

Ok, so now I'M confused! Do we have a bug here or not? What IS the bug in such case?

[atoponce]

Well, all I can tell you is that I still cannot mount a Samba share when using "zfs share" with "sharesmb=on", whether I use underscores, directory paths or datasets. Doesn't matter if I try "//eightyeight/pool_srv", "//eightyeight/pool/srv" or "//eightyeight/srv", it won't mount. The Samba clients can see that the share exists, but can't do anything with it. Further, I can mount the //eightyeight/srv directory path fine using native Samba config, getting ZFS out of the way.

So, if there exists some documentation on how to do this correctly, I would be much appreciated, but everything I've thrown at it shows me that I cannot mount a Samba share using ZFS natively. Has anyone even tried this? Or, are we arguing for the sake of argument?

[atoponce]

Okay. So, tearing everything down, and starting from scratch, I am getting a "permission denied" error, as guest, my user, and root. So, I'm guessing I also need to make some modifications in the smb.conf. Again, docs would be helpful, seeing as though the Solaris ones from Oracle only go so far.

[FransUrbo]

It's all in the man page - 'man zfs'. And the user you're trying to auth as must have access to the FS, naturally. Can you auth as 'my user' normally (i.e., against another share, not shared via zfs)?

[aikudinov]

There is no bug, Aaron is just confused with how samba share names work, he seems to expect is to be same as mountpoint.
Nevertheless being able to change share name like on solaris would be nice feature. :)

edit: Check how usershares work in samba, because this is what zfs does. All their options are most likely stored in /var/lib/samba/usershares

[atoponce]

I guess I'm confused, because the Samba tools share a directory. ZFS isn't doing that. :)

[atoponce]

I'll close the ticket.

[FransUrbo]

Aikudinov, just for the record. Did you get it to work? It works for me, but there might be two other bugs lurking here:

1. Documentation (see CIFS share documentation lacking #1181).
2. Changing share name (see CIFS options missing #1182).