Re: BUG when doing parallel NFS mounts (WAS: Re: Merge windowclosed: v2.6.19-rc1)

[Trond Myklebust]

On Sun, 2006-10-08 at 20:54 +0200, Peter Osterlund wrote:
> Trond Myklebust <trond.myklebust@xxxxxxxxxx> writes:
> 
> > On Sun, 2006-10-08 at 17:19 +0200, Peter Osterlund wrote:
> > > > kernel BUG at fs/nfs/client.c:352!
> > 
> > Does the following patch fix it?
> 
> Yes it does. Thanks!

Hmm... There would appear to be another bug there. After breaking out of
the loop, the task state is left as TASK_INTERRUPTIBLE. Let's just
replace the whole thing with a wait_on_event_interruptible.

Cheers,
  Trond
> --- Begin Message ---
> NFS_CS_INITING > NFS_CS_READY, so instead of waiting for the structure to
> get initialised, we currently immediately jump out of the loop without ever
> sleeping.
>
> It is also possible to break out of the loop while still in
> TASK_INTERRUPTIBLE. Replace by wait_event_interruptible, which doesn't
> suffer from these problems.
>
> Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> ---
>
>  fs/nfs/client.c |   24 +++++-------------------
>  1 files changed, 5 insertions(+), 19 deletions(-)
>
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index 6e4e48c..013cdbc 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -322,25 +322,11 @@ found_client:
>  	if (new)
>  		nfs_free_client(new);
>  
> -	if (clp->cl_cons_state == NFS_CS_INITING) {
> -		DECLARE_WAITQUEUE(myself, current);
> -
> -		add_wait_queue(&nfs_client_active_wq, &myself);
> -
> -		for (;;) {
> -			set_current_state(TASK_INTERRUPTIBLE);
> -			if (signal_pending(current) ||
> -			    clp->cl_cons_state > NFS_CS_READY)
> -				break;
> -			schedule();
> -		}
> -
> -		remove_wait_queue(&nfs_client_active_wq, &myself);
> -
> -		if (signal_pending(current)) {
> -			nfs_put_client(clp);
> -			return ERR_PTR(-ERESTARTSYS);
> -		}
> +	error = wait_event_interruptible(&nfs_client_active_wq,
> +				clp->cl_cons_state != NFS_CS_INITING);
> +	if (error < 0) {
> +		nfs_put_client(clp);
> +		return ERR_PTR(-ERESTARTSYS);
>  	}
>  
>  	if (clp->cl_cons_state < NFS_CS_READY) {
>
> --- End Message ---