Re: [PATCH v4] SUNRPC: fix races on PipeFS UMOUNT notifications

From: William Dauchy
Date: Fri Jun 28 2013 - 07:51:50 EST


On Wed, Jun 26, 2013 at 8:15 AM, Stanislav Kinsbursky
<skinsbursky@xxxxxxxxxxxxx> wrote:
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index b827a4b..41f180c 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -236,8 +236,6 @@ static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
> continue;
> if (rpc_clnt_skip_event(clnt, event))
> continue;
> - if (atomic_inc_not_zero(&clnt->cl_count) == 0)
> - continue;
> spin_unlock(&sn->rpc_client_lock);
> return clnt;
> }
> @@ -254,7 +252,6 @@ static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
>
> while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
> error = __rpc_pipefs_event(clnt, event, sb);
> - rpc_release_client(clnt);
> if (error)
> break;
> }
> @@ -641,8 +638,8 @@ rpc_free_client(struct rpc_clnt *clnt)
> rcu_dereference(clnt->cl_xprt)->servername);
> if (clnt->cl_parent != clnt)
> rpc_release_client(clnt->cl_parent);
> - rpc_unregister_client(clnt);
> rpc_clnt_remove_pipedir(clnt);
> + rpc_unregister_client(clnt);
> rpc_free_iostats(clnt->cl_metrics);
> kfree(clnt->cl_principal);
> clnt->cl_metrics = NULL;
> diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
> index c512448..9b4ec5b 100644
> --- a/net/sunrpc/rpc_pipe.c
> +++ b/net/sunrpc/rpc_pipe.c
> @@ -1165,12 +1165,12 @@ static void rpc_kill_sb(struct super_block *sb)
> goto out;
> }
> sn->pipefs_sb = NULL;
> - mutex_unlock(&sn->pipefs_sb_lock);
> dprintk("RPC: sending pipefs UMOUNT notification for net %p%s\n",
> net, NET_NAME(net));
> blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
> RPC_PIPEFS_UMOUNT,
> sb);
> + mutex_unlock(&sn->pipefs_sb_lock);
> put_net(net);
> out:
> kill_litter_super(sb);

are these patches validated?
any chance to see them in tree soon? I wasn't able to find them on
http://git.linux-nfs.org/?p=trondmy/linux-nfs.git

Thanks,
--
William
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