freebsd stable - May 2013 - multiple NFS mounts with bg,retrycount=0

I updated a FreeBSD 9-STABLE system to r250290 and noticed an NFS oddity
-- fstab entries that specify a retrycnt are mounted multiple times.

I have this in /etc/fstab:
xxxx:/remote/yyyy /local/zzzz nfs rw,bg,retrycnt=0 0 0

And this in /etc/rc.conf:
rpcbind_enable="YES"
nfs_client_enable="YES"
nfs_server_enable="YES"
nfsv4_server_enable="YES"
nfsuserd_flags="-domain XXXXXX"
rpc_lockd_enable="YES"
rpc_statd_enable="YES"

If I run mount immediately after the system boots up I don't see
anything mounted on /local/zzzz.  If I wait a minute or so and recheck I
see two identical mounts on /local/zzzz.

# mount | grep /local
xxxx:/remote/yyyy on /local/zzzz (nfs)
xxxx:/remote/yyyy on /local/zzzz (nfs)

It is almost as if the system tried to mount the remote FS, failed, and
then forked multiple (?) processes to retry the operation, and all of
them succeed later.  Unfortunately, I can't reboot the system for a
couple of days so I can't go looking for mount_nfs processes right after
a fresh boot.

Regards,
Navdeep

[about double background NFS mounts]

I'm not sure on the fix to this, but I'm pretty sure it's because we
retry
the mount -a stuff twice at startup.  If you watch your console, you'll see
two places where it will "mount NFS filesystems" during boot.

... well... a fix to this would be to _not_ do that twice ... but hey :).

On Mon, 2013-05-06 at 10:48 -0700, Navdeep Parhar wrote:
> I updated a FreeBSD 9-STABLE system to r250290 and noticed an NFS oddity
> -- fstab entries that specify a retrycnt are mounted multiple times.
> 
> I have this in /etc/fstab:
> xxxx:/remote/yyyy /local/zzzz nfs rw,bg,retrycnt=0 0 0
> 
> And this in /etc/rc.conf:
> rpcbind_enable="YES"
> nfs_client_enable="YES"
> nfs_server_enable="YES"
> nfsv4_server_enable="YES"
> nfsuserd_flags="-domain XXXXXX"
> rpc_lockd_enable="YES"
> rpc_statd_enable="YES"
> 
> If I run mount immediately after the system boots up I don't see
> anything mounted on /local/zzzz.  If I wait a minute or so and recheck I
> see two identical mounts on /local/zzzz.
> 
> # mount | grep /local
> xxxx:/remote/yyyy on /local/zzzz (nfs)
> xxxx:/remote/yyyy on /local/zzzz (nfs)
> 
> It is almost as if the system tried to mount the remote FS, failed, and
> then forked multiple (?) processes to retry the operation, and all of
> them succeed later.  Unfortunately, I can't reboot the system for a
> couple of days so I can't go looking for mount_nfs processes right
after
> a fresh boot.
> 
> Regards,
> Navdeep

I see the very same here on FreeBSD 10.0-CURRENT boxes (two boxes acting
as NFSv4 server). The clients (all FBSD 10, one 9.1-STABLE) have two(!)
identical mounts of the very same filesystem.

/etc/fstab does contain the mount option "bg", but not
"retrycnt=0".

This behaviour happens on ALL FBSD 10.0-CURRENT boxes I administer
(10.0-CURRENT #0 r250275: Sun May  5 18:40:17 CEST 2013 amd64).


Regards,

Oliver
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