From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031645Ab2CGATx (ORCPT ); Tue, 6 Mar 2012 19:19:53 -0500 Received: from mx2.netapp.com ([216.240.18.37]:50875 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932682Ab2CGATv (ORCPT ); Tue, 6 Mar 2012 19:19:51 -0500 X-IronPort-AV: E=Sophos;i="4.73,542,1325491200"; d="scan'208";a="631276447" From: "Myklebust, Trond" To: Stanislav Kinsbursky CC: "linux-nfs@vger.kernel.org" , "xemul@parallels.com" , "neilb@suse.de" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "jbottomley@parallels.com" , "bfields@fieldses.org" , "davem@davemloft.net" , "devel@openvz.org" Subject: Re: [PATCH] SUNRPC: set desired file system root before connecting local transports Thread-Topic: [PATCH] SUNRPC: set desired file system root before connecting local transports Thread-Index: AQHM9vLHZdm7svM3nkmFIPo1sSpgIZZeiDkA Date: Wed, 7 Mar 2012 00:19:48 +0000 Message-ID: <1331079588.10560.55.camel@lade.trondhjem.org> References: <20120229145915.24030.31551.stgit@localhost6.localdomain6> In-Reply-To: <20120229145915.24030.31551.stgit@localhost6.localdomain6> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.104.60.115] Content-Type: text/plain; charset="utf-8" Content-ID: <1E0E74313C142F4582D2DBA3872510C1@tahoe.netapp.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id q270K0Zl011487 On Wed, 2012-02-29 at 18:59 +0400, Stanislav Kinsbursky wrote: > Today, there is a problem in connecting of local SUNRPC thansports. These > transports uses UNIX sockets and connection itself is done by rpciod workqueue. > But UNIX sockets lookup is done in context of process file system root. I.e. > all local thunsports are connecting in rpciod context. > This works nice until we will try to mount NFS from process with other root - > for example in container. This container can have it's own (nested) root and > rcpbind process, listening on it's own unix sockets. But NFS mount attempt in > this container will register new service (Lockd for example) in global rpcbind > - not containers's one. > This patch solves the problem by switching rpciod kernel thread's file system > root to right one (stored on transport) while connecting of local transports. > > Signed-off-by: Stanislav Kinsbursky > > --- > fs/fs_struct.c | 1 + > net/sunrpc/xprtsock.c | 32 ++++++++++++++++++++++++++++++-- > 2 files changed, 31 insertions(+), 2 deletions(-) > > diff --git a/fs/fs_struct.c b/fs/fs_struct.c > index 78b519c..0f984c3 100644 > --- a/fs/fs_struct.c > +++ b/fs/fs_struct.c > @@ -36,6 +36,7 @@ void set_fs_root(struct fs_struct *fs, struct path *path) > if (old_root.dentry) > path_put_longterm(&old_root); > } > +EXPORT_SYMBOL_GPL(set_fs_root); > > /* > * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values. > diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c > index 4c8281d..c94c181 100644 > --- a/net/sunrpc/xprtsock.c > +++ b/net/sunrpc/xprtsock.c > @@ -37,6 +37,7 @@ > #include > #include > #include > +#include > #ifdef CONFIG_SUNRPC_BACKCHANNEL > #include > #endif > @@ -255,6 +256,11 @@ struct sock_xprt { > void (*old_state_change)(struct sock *); > void (*old_write_space)(struct sock *); > void (*old_error_report)(struct sock *); > + > + /* > + * Saved transport creator root. Required for local transports only. > + */ > + struct path root; > }; > > /* > @@ -1891,6 +1897,7 @@ static void xs_local_setup_socket(struct work_struct *work) > struct rpc_xprt *xprt = &transport->xprt; > struct socket *sock; > int status = -EIO; > + struct path root; > > if (xprt->shutdown) > goto out; > @@ -1908,7 +1915,14 @@ static void xs_local_setup_socket(struct work_struct *work) > dprintk("RPC: worker connecting xprt %p via AF_LOCAL to %s\n", > xprt, xprt->address_strings[RPC_DISPLAY_ADDR]); > > + get_fs_root(current->fs, &root); > + set_fs_root(current->fs, &transport->root); > + > status = xs_local_finish_connecting(xprt, sock); > + > + set_fs_root(current->fs, &root); > + path_put(&root); > + > switch (status) { > case 0: Hi Stanislav, What happens here if the mount namespace of the process that originally created the sock_xprt no longer exists? Should we care about that case? Cheers Trond -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I