Is NFSv4 mount interruptible?

[Slawa Olhovchenkov]

On Wed, Aug 03, 2016 at 01:55:02AM +0300, Slawa Olhovchenkov wrote:

> On Tue, Aug 02, 2016 at 10:48:52PM +0000, Rick Macklem wrote:
> 
> > Slawa wrote:
> > >I have autofs NFSv4 mount with /etc/nfs.map:
> > >
> > >/NFS    -nfsv4,intr,soft,sec=krb5i,gssname=host storage01:/
> > >
> > >Currently I am see NFS hung and I am can't kill shell and can't
> > >unmount /NFS.
> > >
> > >Is NFSv4 mount interruptible?
> > >Or intr support only by NFSv3?
> > Well, in the BUGS section of "man mount_nfs" it notes that soft and intr cannot be
> > safely used with NFSv4. The problem is that, if an RPC that updates state (Open, Close,...)
> > terminates, then the state is no longer usable.
> > 
> > You can "umount -f" the file system, but only if no other "umount" is already in progress.
> > (I am working on a new umount option that will allow "umount -f" to succeed when another
> >  umount is stuck. It requires "umount(8)" to avoid all the path checking, etc.)
> > 
> > Personally, I would never use "soft" for any mount (except read-only maybe), since it can
> > result in a write failure when the NFS server is slow. Using "intr" should be ok for NFSv3,
> > since it is stateless.
> 
> For me, this mount like r/o.
> I am don't have significant write to this mount.
> If some data lost I am able to create this data again.
> Currently NFS hang after long idle.
> 
> I am try to do umount, w/o success:
> 
> # ps -ax | grep mou
>   706  -  Is        0:00.00 /usr/sbin/moused -p /dev/ums0 -t auto -I /var/run/moused.ums0.pid
>  1116  -  Ds        1:16.50 /usr/sbin/autounmountd
> 86794  3- T+        0:00.00 umount -f /NFS
> 
> # procstat 86794
>   PID  PPID  PGID   SID  TSID THR LOGIN    WCHAN     EMUL          COMM        
> 86794 86791 86794 86788 86788   1 admin    autofsvl  FreeBSD ELF64 umount      
> 
> # procstat 1116
>   PID  PPID  PGID   SID  TSID THR LOGIN    WCHAN     EMUL          COMM
>  1116     1  1116  1116     0   1 root     newnfs    FreeBSD ELF64 autounmountd
> 

May be this is autofs issuse? Can be autofsvlk lock leaks?

# procstat -a | grep autofsvl
23767 23759 23757 23738     0   1 root     autofsvl  FreeBSD ELF64 find        
27588  1067 27588 27588     0   1 root     autofsvl  FreeBSD ELF64 sshd        
27722  1067 27722 27722     0   1 root     autofsvl  FreeBSD ELF64 sshd        
28520 28519 28520 28513 28513   1 admin    autofsvl  FreeBSD ELF64 csh         
44829 44825 44717 44717     0   1 root     autofsvl  FreeBSD ELF64 find        
86577  1067 86577 86577     0   1 root     autofsvl  FreeBSD ELF64 sshd        
86588 86587 86588 86582 86582   1 admin    autofsvl  FreeBSD ELF64 csh         
86794 86791 86794 86788 86788   1 admin    autofsvl  FreeBSD ELF64 umount      

# procstat -k 23767 27588 27722 28520 44829 86577 86588 86794
  PID    TID COMM             TDNAME           KSTACK                       
23767 101917 find             -                mi_switch sleepq_wait _sx_xlock_hard _sx_xlock autofs_node_vn lookup namei kern_statat_vnhook sys_fstatat amd64_syscall Xfast_syscall 
27588 102087 sshd             -                mi_switch sleepq_wait _sx_xlock_hard _sx_xlock autofs_node_vn lookup namei vn_open_cred kern_openat amd64_syscall Xfast_syscall 
27722 101649 sshd             -                mi_switch sleepq_wait _sx_xlock_hard _sx_xlock autofs_node_vn lookup namei vn_open_cred kern_openat amd64_syscall Xfast_syscall 
28520 101961 csh              -                mi_switch sleepq_wait _sx_xlock_hard _sx_xlock autofs_node_vn lookup namei kern_statat_vnhook sys_stat amd64_syscall Xfast_syscall 
44829 102258 find             -                mi_switch sleepq_wait _sx_xlock_hard _sx_xlock autofs_node_vn lookup namei kern_statat_vnhook sys_fstatat amd64_syscall Xfast_syscall 
86577 101721 sshd             -                mi_switch sleepq_wait _sx_xlock_hard _sx_xlock autofs_node_vn lookup namei vn_open_cred kern_openat amd64_syscall Xfast_syscall 
86588 101765 csh              -                mi_switch sleepq_wait _sx_xlock_hard _sx_xlock autofs_node_vn lookup namei kern_statat_vnhook sys_stat amd64_syscall Xfast_syscall 
86794 101690 umount           -                mi_switch sleepq_wait _sx_xlock_hard _sx_xlock autofs_node_vn lookup namei kern_statfs sys_statfs amd64_syscall Xfast_syscall