Recurring problem: processes block accessing UFS file system

[Don Lewis]

On  5 Jan, Denis Shaposhnikov wrote:
>>>>>> "Don" == Don Lewis <truckman at FreeBSD.org> writes:
> 
>  Don> pid 519 wants to lock this vnode but some other thread is
>  Don> holding the vnode lock.  Unfortunately we don't know who the
>  Don> lock holder is because the message is truncated.
> 
> Is it possible to find out the answer from the crashdump?

It's possible if you have the matching debug kernel, though it is more
painful.  In kgdb:
	print *(struct vnode *)0xc691f318
	print (struct vnode *)0xc691f318->v_vnlock->lk_lockholder->td_proc->p_pid)
or something like that.

>  Don> This might just be a vnode lock leak.  Build a debug kernel with
>  Don> the DEBUG_VFS_LOCKS and DEBUG_LOCKS options and see if anything
>  Don> shows up.
> 
> I'll try, thank you.

Are you using any unusual file systems, such as nullfs or unionfs?