[Q] I tried to mount nfs_server:/mnt volume, but It mounted another volume.

[Q] I tried to mount nfs_server:/mnt volume, but It mounted another volume.

[Hiroyuki Sato]

Hello lists

OS: CentOS 5.5
kernel: 2.6.36 rebuild myself.


  I'm trying to test NFS/RDMA.
  I tried to mount nfs_server:/mnt volume on on nfs_client
  but It mounted nfs_server:/nfstest volume

  note: /nfstest is tmpfs

 this is mount output
    tmpfs on /nfstest type tmpfs (rw,size=4g)
    /dev/sdb1 on /mnt type ext3 (rw)

  Is this bug??

NFS server config

  # ls -1 /mnt
  This_is_mnt_volume

  # ls -1 /nfstest
  This_is_nfstest_volume

  # cat /etc/exports
  /nfstest   192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
  /mnt       192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)


  # modprobe svcrdma

  # /sbin/service nfs start

  # echo rdma 20049 > /proc/fs/nfsd/portlist


Client Setting

  /sbin/modprobe xprtrdma
  /sbin/mount.rnfs 192.168.100.231:/mnt /mnt -i -o rdma,port=20049

  # ls -1 /mnt
  This_is_nfstest_volume

NFS Server log
  sysctl -w sunrpc.nfsd_debug=1023

  Nov 21 20:47:37 dell1435 mountd[3575]: authenticated mount request
from 192.168.100.232:766 for /mnt (/mnt)
  Nov 21 20:47:37 dell1435 mountd[3575]: /nfstest and /mnt have same
filehandle for 192.168.100.0/255.255.255.0, using first
  Nov 21 20:48:55 dell1435 mountd[3575]: authenticated unmount request
from 192.168.100.232:912 for /mnt (/mnt)
  Nov 21 20:48:55 dell1435 mountd[3575]: authenticated unmount request
from 192.168.100.232:913 for /mnt (/mnt)
  Nov 21 20:49:00 dell1435 mountd[3575]: authenticated unmount request
from 192.168.100.232:917 for /mnt (/mnt)
  Nov 21 20:49:16 dell1435 mountd[3575]: authenticated mount request
from 192.168.100.232:865 for /mnt (/mnt)
  Nov 21 21:02:22 dell1435 mountd[3575]: authenticated unmount request
from 192.168.100.232:955 for /mnt (/mnt)
  Nov 21 21:02:26 dell1435 mountd[3575]: authenticated mount request
from 192.168.100.232:884 for /mnt (/mnt)
  Nov 21 21:02:26 dell1435 kernel: nfsd: exp_rootfh(/mnt
[ffff88011f586740] 192.168.100.0/255.255.255.0:sdb1/2)


--
Hiroyuki Sato
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Re: [Q] I tried to mount nfs_server:/mnt volume, but It mounted another volume.

[Boaz Harrosh]

On 11/21/2010 02:23 PM, Hiroyuki Sato wrote:
> Hello lists
> 
> OS: CentOS 5.5
> kernel: 2.6.36 rebuild myself.
> 
> 
>   I'm trying to test NFS/RDMA.
>   I tried to mount nfs_server:/mnt volume on on nfs_client
>   but It mounted nfs_server:/nfstest volume
> 
>   note: /nfstest is tmpfs
> 
>  this is mount output
>     tmpfs on /nfstest type tmpfs (rw,size=4g)
>     /dev/sdb1 on /mnt type ext3 (rw)
> 
>   Is this bug??
> 
> NFS server config
> 
>   # ls -1 /mnt
>   This_is_mnt_volume
> 
>   # ls -1 /nfstest
>   This_is_nfstest_volume
> 
>   # cat /etc/exports
>   /nfstest   192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
>   /mnt       192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
> 

You must not have two exports with fsid=0. First one is picked. 

nfs4 will only export a single name space point, other exports are
subdirs of that root export. (use bind mounts to present a single
directory tree)

<http://www.citi.umich.edu/projects/nfsv4/linux/using-nfsv4.html>

NFSv4 exports on linux
~~~~~~~~~~~~~~~~~~~~~~

NFSv4 no longer has a separate "mount" protocol. Instead of exporting a number of distinct exports, an NFSv4 client sees the NFSv4 server's exports as existing inside a single filesystem, called the nfsv4 "pseudofilesystem".

On the current linux implementation, the pseudofilesystem is a single real filesystem, identified at export with the fsid=0 option.

In the example above, we exported only a single filesystem, which the client mounted as "/". You can provide clients with multiple filesystems to mount, producing NFSv3-like-behavior, by creative use of mount --bind. For example, you could export /usr/local/bin to clients as /bin and /usr/local/etc as /etc as follows:

mkdir /export
mkdir /export/bin
mkdir /export/etc
mount --bind /usr/local/bin /export/bin
mount --bind /usr/local/etc /export/etc
exportfs -ofsid=0,insecure,no_subtree_check *:/export
exportfs -orw,nohide,insecure,no_subtree_check *:/export/bin
exportfs -orw,nohide,insecure,no_subtree_check *:/export/etc

Note that the paths returned by the "showmount" program are meaningful only to clients using nfs versions 2 and 3; in the above example, "showmount" will list the paths /export, /export/bin/, and /export/etc, but nfsv4 clients should mount yourserver:/, yourserver:/bin, or yourserver:/etc.

</http://www.citi.umich.edu/projects/nfsv4/linux/using-nfsv4.html>

Boaz
> 
>   # modprobe svcrdma
> 
>   # /sbin/service nfs start
> 
>   # echo rdma 20049 > /proc/fs/nfsd/portlist
> 
> 
> Client Setting
> 
>   /sbin/modprobe xprtrdma
>   /sbin/mount.rnfs 192.168.100.231:/mnt /mnt -i -o rdma,port=20049
> 
>   # ls -1 /mnt
>   This_is_nfstest_volume
> 
> NFS Server log
>   sysctl -w sunrpc.nfsd_debug=1023
> 
>   Nov 21 20:47:37 dell1435 mountd[3575]: authenticated mount request
> from 192.168.100.232:766 for /mnt (/mnt)
>   Nov 21 20:47:37 dell1435 mountd[3575]: /nfstest and /mnt have same
> filehandle for 192.168.100.0/255.255.255.0, using first
>   Nov 21 20:48:55 dell1435 mountd[3575]: authenticated unmount request
> from 192.168.100.232:912 for /mnt (/mnt)
>   Nov 21 20:48:55 dell1435 mountd[3575]: authenticated unmount request
> from 192.168.100.232:913 for /mnt (/mnt)
>   Nov 21 20:49:00 dell1435 mountd[3575]: authenticated unmount request
> from 192.168.100.232:917 for /mnt (/mnt)
>   Nov 21 20:49:16 dell1435 mountd[3575]: authenticated mount request
> from 192.168.100.232:865 for /mnt (/mnt)
>   Nov 21 21:02:22 dell1435 mountd[3575]: authenticated unmount request
> from 192.168.100.232:955 for /mnt (/mnt)
>   Nov 21 21:02:26 dell1435 mountd[3575]: authenticated mount request
> from 192.168.100.232:884 for /mnt (/mnt)
>   Nov 21 21:02:26 dell1435 kernel: nfsd: exp_rootfh(/mnt
> [ffff88011f586740] 192.168.100.0/255.255.255.0:sdb1/2)
> 
> 
> --
> Hiroyuki Sato
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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Re: [Q] I tried to mount nfs_server:/mnt volume, but It mounted another volume.

[J. Bruce Fields]

On Sun, Nov 21, 2010 at 03:41:18PM +0200, Boaz Harrosh wrote:
> On 11/21/2010 02:23 PM, Hiroyuki Sato wrote:
> > Hello lists
> > 
> > OS: CentOS 5.5
> > kernel: 2.6.36 rebuild myself.
> > 
> > 
> >   I'm trying to test NFS/RDMA.
> >   I tried to mount nfs_server:/mnt volume on on nfs_client
> >   but It mounted nfs_server:/nfstest volume
> > 
> >   note: /nfstest is tmpfs
> > 
> >  this is mount output
> >     tmpfs on /nfstest type tmpfs (rw,size=4g)
> >     /dev/sdb1 on /mnt type ext3 (rw)
> > 
> >   Is this bug??
> > 
> > NFS server config
> > 
> >   # ls -1 /mnt
> >   This_is_mnt_volume
> > 
> >   # ls -1 /nfstest
> >   This_is_nfstest_volume
> > 
> >   # cat /etc/exports
> >   /nfstest   192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
> >   /mnt       192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
> > 
> 
> You must not have two exports with fsid=0. First one is picked. 
> 
> nfs4 will only export a single name space point, other exports are
> subdirs of that root export. (use bind mounts to present a single
> directory tree)
> 
> <http://www.citi.umich.edu/projects/nfsv4/linux/using-nfsv4.html>

We should update and/or replace that documentation; with new nfs-utils
and kernel, if you omit the "fsid=0", you'll end up with an nfsv4
namespace that's the same as v2/v3's always was.

--b.

> 
> NFSv4 exports on linux
> ~~~~~~~~~~~~~~~~~~~~~~
> 
> NFSv4 no longer has a separate "mount" protocol. Instead of exporting a number of distinct exports, an NFSv4 client sees the NFSv4 server's exports as existing inside a single filesystem, called the nfsv4 "pseudofilesystem".
> 
> On the current linux implementation, the pseudofilesystem is a single real filesystem, identified at export with the fsid=0 option.
> 
> In the example above, we exported only a single filesystem, which the client mounted as "/". You can provide clients with multiple filesystems to mount, producing NFSv3-like-behavior, by creative use of mount --bind. For example, you could export /usr/local/bin to clients as /bin and /usr/local/etc as /etc as follows:
> 
> mkdir /export
> mkdir /export/bin
> mkdir /export/etc
> mount --bind /usr/local/bin /export/bin
> mount --bind /usr/local/etc /export/etc
> exportfs -ofsid=0,insecure,no_subtree_check *:/export
> exportfs -orw,nohide,insecure,no_subtree_check *:/export/bin
> exportfs -orw,nohide,insecure,no_subtree_check *:/export/etc
> 
> Note that the paths returned by the "showmount" program are meaningful only to clients using nfs versions 2 and 3; in the above example, "showmount" will list the paths /export, /export/bin/, and /export/etc, but nfsv4 clients should mount yourserver:/, yourserver:/bin, or yourserver:/etc.
> 
> </http://www.citi.umich.edu/projects/nfsv4/linux/using-nfsv4.html>
> 
> Boaz
> > 
> >   # modprobe svcrdma
> > 
> >   # /sbin/service nfs start
> > 
> >   # echo rdma 20049 > /proc/fs/nfsd/portlist
> > 
> > 
> > Client Setting
> > 
> >   /sbin/modprobe xprtrdma
> >   /sbin/mount.rnfs 192.168.100.231:/mnt /mnt -i -o rdma,port=20049
> > 
> >   # ls -1 /mnt
> >   This_is_nfstest_volume
> > 
> > NFS Server log
> >   sysctl -w sunrpc.nfsd_debug=1023
> > 
> >   Nov 21 20:47:37 dell1435 mountd[3575]: authenticated mount request
> > from 192.168.100.232:766 for /mnt (/mnt)
> >   Nov 21 20:47:37 dell1435 mountd[3575]: /nfstest and /mnt have same
> > filehandle for 192.168.100.0/255.255.255.0, using first
> >   Nov 21 20:48:55 dell1435 mountd[3575]: authenticated unmount request
> > from 192.168.100.232:912 for /mnt (/mnt)
> >   Nov 21 20:48:55 dell1435 mountd[3575]: authenticated unmount request
> > from 192.168.100.232:913 for /mnt (/mnt)
> >   Nov 21 20:49:00 dell1435 mountd[3575]: authenticated unmount request
> > from 192.168.100.232:917 for /mnt (/mnt)
> >   Nov 21 20:49:16 dell1435 mountd[3575]: authenticated mount request
> > from 192.168.100.232:865 for /mnt (/mnt)
> >   Nov 21 21:02:22 dell1435 mountd[3575]: authenticated unmount request
> > from 192.168.100.232:955 for /mnt (/mnt)
> >   Nov 21 21:02:26 dell1435 mountd[3575]: authenticated mount request
> > from 192.168.100.232:884 for /mnt (/mnt)
> >   Nov 21 21:02:26 dell1435 kernel: nfsd: exp_rootfh(/mnt
> > [ffff88011f586740] 192.168.100.0/255.255.255.0:sdb1/2)
> > 
> > 
> > --
> > Hiroyuki Sato
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> --
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Re: [Q] I tried to mount nfs_server:/mnt volume, but It mounted another volume.

[Hiroyuki Sato]

Thank you useful information. I'll study about NFSv4

--
Hiroyuki Sato

2010/11/22 J. Bruce Fields <bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>:
> On Sun, Nov 21, 2010 at 03:41:18PM +0200, Boaz Harrosh wrote:
>> On 11/21/2010 02:23 PM, Hiroyuki Sato wrote:
>> > Hello lists
>> >
>> > OS: CentOS 5.5
>> > kernel: 2.6.36 rebuild myself.
>> >
>> >
>> >   I'm trying to test NFS/RDMA.
>> >   I tried to mount nfs_server:/mnt volume on on nfs_client
>> >   but It mounted nfs_server:/nfstest volume
>> >
>> >   note: /nfstest is tmpfs
>> >
>> >  this is mount output
>> >     tmpfs on /nfstest type tmpfs (rw,size=4g)
>> >     /dev/sdb1 on /mnt type ext3 (rw)
>> >
>> >   Is this bug??
>> >
>> > NFS server config
>> >
>> >   # ls -1 /mnt
>> >   This_is_mnt_volume
>> >
>> >   # ls -1 /nfstest
>> >   This_is_nfstest_volume
>> >
>> >   # cat /etc/exports
>> >   /nfstest   192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
>> >   /mnt       192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
>> >
>>
>> You must not have two exports with fsid=0. First one is picked.
>>
>> nfs4 will only export a single name space point, other exports are
>> subdirs of that root export. (use bind mounts to present a single
>> directory tree)
>>
>> <http://www.citi.umich.edu/projects/nfsv4/linux/using-nfsv4.html>
>
> We should update and/or replace that documentation; with new nfs-utils
> and kernel, if you omit the "fsid=0", you'll end up with an nfsv4
> namespace that's the same as v2/v3's always was.
>
> --b.
>
>>
>> NFSv4 exports on linux
>> ~~~~~~~~~~~~~~~~~~~~~~
>>
>> NFSv4 no longer has a separate "mount" protocol. Instead of exporting a number of distinct exports, an NFSv4 client sees the NFSv4 server's exports as existing inside a single filesystem, called the nfsv4 "pseudofilesystem".
>>
>> On the current linux implementation, the pseudofilesystem is a single real filesystem, identified at export with the fsid=0 option.
>>
>> In the example above, we exported only a single filesystem, which the client mounted as "/". You can provide clients with multiple filesystems to mount, producing NFSv3-like-behavior, by creative use of mount --bind. For example, you could export /usr/local/bin to clients as /bin and /usr/local/etc as /etc as follows:
>>
>> mkdir /export
>> mkdir /export/bin
>> mkdir /export/etc
>> mount --bind /usr/local/bin /export/bin
>> mount --bind /usr/local/etc /export/etc
>> exportfs -ofsid=0,insecure,no_subtree_check *:/export
>> exportfs -orw,nohide,insecure,no_subtree_check *:/export/bin
>> exportfs -orw,nohide,insecure,no_subtree_check *:/export/etc
>>
>> Note that the paths returned by the "showmount" program are meaningful only to clients using nfs versions 2 and 3; in the above example, "showmount" will list the paths /export, /export/bin/, and /export/etc, but nfsv4 clients should mount yourserver:/, yourserver:/bin, or yourserver:/etc.
>>
>> </http://www.citi.umich.edu/projects/nfsv4/linux/using-nfsv4.html>
>>
>> Boaz
>> >
>> >   # modprobe svcrdma
>> >
>> >   # /sbin/service nfs start
>> >
>> >   # echo rdma 20049 > /proc/fs/nfsd/portlist
>> >
>> >
>> > Client Setting
>> >
>> >   /sbin/modprobe xprtrdma
>> >   /sbin/mount.rnfs 192.168.100.231:/mnt /mnt -i -o rdma,port=20049
>> >
>> >   # ls -1 /mnt
>> >   This_is_nfstest_volume
>> >
>> > NFS Server log
>> >   sysctl -w sunrpc.nfsd_debug=1023
>> >
>> >   Nov 21 20:47:37 dell1435 mountd[3575]: authenticated mount request
>> > from 192.168.100.232:766 for /mnt (/mnt)
>> >   Nov 21 20:47:37 dell1435 mountd[3575]: /nfstest and /mnt have same
>> > filehandle for 192.168.100.0/255.255.255.0, using first
>> >   Nov 21 20:48:55 dell1435 mountd[3575]: authenticated unmount request
>> > from 192.168.100.232:912 for /mnt (/mnt)
>> >   Nov 21 20:48:55 dell1435 mountd[3575]: authenticated unmount request
>> > from 192.168.100.232:913 for /mnt (/mnt)
>> >   Nov 21 20:49:00 dell1435 mountd[3575]: authenticated unmount request
>> > from 192.168.100.232:917 for /mnt (/mnt)
>> >   Nov 21 20:49:16 dell1435 mountd[3575]: authenticated mount request
>> > from 192.168.100.232:865 for /mnt (/mnt)
>> >   Nov 21 21:02:22 dell1435 mountd[3575]: authenticated unmount request
>> > from 192.168.100.232:955 for /mnt (/mnt)
>> >   Nov 21 21:02:26 dell1435 mountd[3575]: authenticated mount request
>> > from 192.168.100.232:884 for /mnt (/mnt)
>> >   Nov 21 21:02:26 dell1435 kernel: nfsd: exp_rootfh(/mnt
>> > [ffff88011f586740] 192.168.100.0/255.255.255.0:sdb1/2)
>> >
>> >
>> > --
>> > Hiroyuki Sato
>> > --
>> > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>> --
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>
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Re: [Q] I tried to mount nfs_server:/mnt volume, but It mounted another volume.

[Roland Dreier]

Yes, as Boaz said, having two exports with fsid=0 is the problem:

 >   # cat /etc/exports
 >   /nfstest   192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)
 >   /mnt       192.168.100.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)

you could have seen this in the server log from this:

 >   Nov 21 20:47:37 dell1435 mountd[3575]: /nfstest and /mnt have same
 > filehandle for 192.168.100.0/255.255.255.0, using first

 - R.
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