From: Tom Tucker Subject: [PATCH] svc: Modify svc_find_xprt to take a reference Date: Fri, 18 Jan 2008 10:51:21 -0600 Message-ID: <20080118165121.9787.8399.stgit@dell3.ogc.int> Content-Type: text/plain; charset=utf-8; format=fixed Cc: linux-nfs@vger.kernel.org To: bfields@fieldses.org Return-path: Received: from 209-198-142-2-host.prismnet.net ([209.198.142.2]:36500 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757290AbYARQvV (ORCPT ); Fri, 18 Jan 2008 11:51:21 -0500 Sender: linux-nfs-owner@vger.kernel.org List-ID: Modify svc_find_xprt to acquire a reference on a transport if it is found. This fixes a race where the transport is found, but removed immediately afterward leaving the caller with a pointer to a dead transport. Signed-off-by: Tom Tucker --- fs/lockd/svc.c | 18 +++++++++++++----- fs/nfsd/nfsctl.c | 1 + net/sunrpc/svc_xprt.c | 1 + 3 files changed, 15 insertions(+), 5 deletions(-) diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index 470af01..0822646 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -227,17 +227,25 @@ lockd(struct svc_rqst *rqstp) static int make_socks(struct svc_serv *serv, int proto) { static int warned; + struct svc_xprt *xprt; int err = 0; - if (proto == IPPROTO_UDP || nlm_udpport) - if (!svc_find_xprt(serv, "udp", 0, 0)) + if (proto == IPPROTO_UDP || nlm_udpport) { + xprt = svc_find_xprt(serv, "udp", 0, 0); + if (!xprt) err = svc_create_xprt(serv, "udp", nlm_udpport, SVC_SOCK_DEFAULTS); - if (err >= 0 && (proto == IPPROTO_TCP || nlm_tcpport)) - if (!svc_find_xprt(serv, "tcp", 0, 0)) + else + svc_xprt_put(xprt); + } + if (err >= 0 && (proto == IPPROTO_TCP || nlm_tcpport)) { + xprt = svc_find_xprt(serv, "tcp", 0, 0); + if (!xprt) err = svc_create_xprt(serv, "tcp", nlm_tcpport, SVC_SOCK_DEFAULTS); - + else + svc_xprt_put(xprt); + } if (err >= 0) { warned = 0; err = 0; diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 10c13ed..d22bc45 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -592,6 +592,7 @@ static ssize_t write_ports(struct file *file, char *buf, size_t size) AF_UNSPEC, port); if (xprt) { svc_close_xprt(xprt); + svc_xprt_put(xprt); err = 0; } else err = -ENOTCONN; diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 5545c1e..c3fb367 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -1007,6 +1007,7 @@ struct svc_xprt *svc_find_xprt(struct svc_serv *serv, char *xcl_name, if (port && port != svc_xprt_local_port(xprt)) continue; found = xprt; + svc_xprt_get(xprt); break; } spin_unlock_bh(&serv->sv_lock);