On Fri, 22 Mar 2013 10:57:21 +0800
ycnian@xxxxxxxxx wrote:
> nfsv4.1 client suspending fails with such info
>
> Freezing of tasks failed after 20.00 seconds (1 tasks refusing to freeze, wq_busy=0):
> nfsv4.1-svc S ffff88007889f2e0 0 3191 2 0x00000080
> ffff88007b2f3e28 0000000000000046 ffff88007b2f2010 00000000000127c0
> ffff880079b08000 00000000000127c0 ffff88007b2f3fd8 00000000000127c0
> ffff88007b2f3fd8 00000000000127c0 ffffffff81a14410 ffff880079b08000
> Call Trace:
> [<ffffffff81441396>] schedule+0x64/0x66
> [<ffffffffa06a6892>] nfs41_callback_svc+0x100/0x129 [nfsv4]
> [<ffffffff8104fdb8>] ? wake_up_bit+0x2a/0x2a
> [<ffffffffa06a6792>] ? nfs_callback_up+0x548/0x548 [nfsv4]
> [<ffffffff8104f7e0>] kthread+0xb5/0xbd
> [<ffffffff8104f72b>] ? kthread_freezable_should_stop+0x65/0x65
> [<ffffffff8144912c>] ret_from_fork+0x7c/0xb0
> [<ffffffff8104f72b>] ? kthread_freezable_should_stop+0x65/0x65
>
> I read such threads
> [1] nfs/sunrpc: allow freezing of tasks with NFS calls in flight
> [2] LOCKDEP: 3.9-rc1: mount.nfs/4272 still has locks held!
> and then modify nfs41_callback_svc(). It works on my machine. I don't know
> the details of freezing, so I'm not sure if the modification is reasonable.
> This is not a formal patch. Thanks.
>
> Signed-off-by: Yanchuan Nian <ycnian@xxxxxxxxx>
> ---
> fs/nfs/callback.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
> index 5088b57..8addb7b 100644
> --- a/fs/nfs/callback.c
> +++ b/fs/nfs/callback.c
> @@ -138,7 +138,7 @@ nfs41_callback_svc(void *vrqstp)
> error);
> } else {
> spin_unlock_bh(&serv->sv_cb_lock);
> - schedule();
> + freezable_schedule();
> }
> finish_wait(&serv->sv_cb_waitq, &wq);
> }
I think it'd be better to have that thread call try_to_freeze()
directly instead of doing this. There are some problems with
freezable_schedule() that still need to be resolved and I suspect that
it will eventually go away entirely.
It's may be sufficient to simply call try_to_freeze() at the top of
the loop, but that would need to be tested.
--
Jeff Layton <jlayton@xxxxxxxxxx>
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