From: NeilBrown <neilb@suse.com>
To: Andy Adamson <andros@netapp.com>,
        Trond Myklebust <trond.myklebust@primarydata.com>,
        Anna Schumaker <anna.schumaker@netapp.com>
Date: Fri, 18 Nov 2016 16:01:09 +1100
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH] NFSv4.1: nfs4_fl_prepare_ds must be careful about reporting success.
In-Reply-To: <87lgxiwoxi.fsf@notabene.neil.brown.name>
References: <87lgxiwoxi.fsf@notabene.neil.brown.name>
Message-ID: <8760nlfkkq.fsf@notabene.neil.brown.name>
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Sender: linux-nfs-owner@vger.kernel.org

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Ping?
No sign of this in linux-next, and no replies....

Thanks,
NeilBrown


On Fri, Oct 21 2016, NeilBrown wrote:

>
> Various places assume that if nfs4_fl_prepare_ds() turns a non-NULL
> 'ds', then ds->ds_clp will also be non-NULL.
>
> This is not necessasrily true in the case when the process received a
> fatal signal while nfs4_pnfs_ds_connect is waiting in
> nfs4_wait_ds_connect().  In that case ->ds_clp may not be set, and the
> devid may not recently have been marked unavailable.
>
> So add a test for ->ds_clp =3D=3D NULL and return NULL in that case.
>
> Fixes: c23266d532b4 ("NFS4.1 Fix data server connection race")
> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
>  fs/nfs/filelayout/filelayoutdev.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nfs/filelayout/filelayoutdev.c b/fs/nfs/filelayout/filela=
youtdev.c
> index 4946ef40ba87..85ef38f9765f 100644
> --- a/fs/nfs/filelayout/filelayoutdev.c
> +++ b/fs/nfs/filelayout/filelayoutdev.c
> @@ -283,7 +283,8 @@ nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, =
u32 ds_idx)
>  			     s->nfs_client->cl_rpcclient->cl_auth->au_flavor);
>=20=20
>  out_test_devid:
> -	if (filelayout_test_devid_unavailable(devid))
> +	if (ret->ds_clp =3D=3D NULL ||
> +	    filelayout_test_devid_unavailable(devid))
>  		ret =3D NULL;
>  out:
>  	return ret;
> --=20
> 2.10.1

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