Re: Killing process in D state on mount to dead NFS server. (when process is in fsync)

From: NeilBrown
Date: Fri Aug 01 2014 - 23:20:35 EST


On Fri, 1 Aug 2014 22:55:42 -0400 Trond Myklebust <trondmy@xxxxxxxxx> wrote:

> > That still leaves some open questions though...
> >
> > Is that enough to fix it? You'd still have the dirty pages lingering
> > around, right? Would a umount -f presumably work at that point?
>
> 'umount -f' will kill any outstanding RPC calls that are causing the
> mount to hang, but doesn't do anything to change page states or NFS
> file/lock states.

Should it though?

MNT_FORCE (since Linux 2.1.116)
Force unmount even if busy. This can cause data loss. (Only
for NFS mounts.)

Given that data loss is explicitly permitted, I suspect it should.

Can we make MNT_FORCE on NFS not only abort outstanding RPC calls, but
fail all subsequent RPC calls? That might make it really useful. You
wouldn't even need to "kill -9" then.

NeilBrown

Attachment: signature.asc
Description: PGP signature