From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Tucker Subject: [PATCH] svc: Clean up deferred requests on transport destruction Date: Mon, 05 Jan 2009 15:21:19 -0600 Message-ID: <496279CF.5050807@opengridcomputing.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: Trond Myklebust , Linux NFS Mailing List To: "J. Bruce Fields" Return-path: Received: from smtp.opengridcomputing.com ([209.198.142.2]:55055 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754817AbZAEVVT (ORCPT ); Mon, 5 Jan 2009 16:21:19 -0500 Sender: linux-nfs-owner@vger.kernel.org List-ID: Bruce, This patch replaces 2/3 of Trond's deferral cleanup patch. This shouldn't come across with the white-spaced munged. Please let me know if it does. Thanks, Tom A race between svc_revisit and svc_delete_xprt can result in deferred requests holding references on a transport that can never be recovered because dead transports are not enqueued for subsequent processing. Check for XPT_DEAD in revisit to clean up completing deferrals on a dead transport and sweep a transport's deferred queue to do the same for queued but unprocessed deferrals. Signed-off-by: Tom Tucker --- net/sunrpc/svc_xprt.c | 25 ++++++++++++++++++------- 1 files changed, 18 insertions(+), 7 deletions(-) diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index bf5b5cd..e6e7e25 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -837,6 +837,11 @@ static void svc_age_temp_xprts(unsigned long closure) void svc_delete_xprt(struct svc_xprt *xprt) { struct svc_serv *serv = xprt->xpt_server; + struct svc_deferred_req *dr; + + /* Only do this once */ + if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags)) + return; dprintk("svc: svc_delete_xprt(%p)\n", xprt); xprt->xpt_ops->xpo_detach(xprt); @@ -851,12 +856,16 @@ void svc_delete_xprt(struct svc_xprt *xprt) * while still attached to a queue, the queue itself * is about to be destroyed (in svc_destroy). */ - if (!test_and_set_bit(XPT_DEAD, &xprt->xpt_flags)) { - BUG_ON(atomic_read(&xprt->xpt_ref.refcount) < 2); - if (test_bit(XPT_TEMP, &xprt->xpt_flags)) - serv->sv_tmpcnt--; + if (test_bit(XPT_TEMP, &xprt->xpt_flags)) + serv->sv_tmpcnt--; + + for (dr = svc_deferred_dequeue(xprt); dr; + dr = svc_deferred_dequeue(xprt)) { svc_xprt_put(xprt); + kfree(dr); } + + svc_xprt_put(xprt); spin_unlock_bh(&serv->sv_lock); } @@ -902,17 +911,19 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many) container_of(dreq, struct svc_deferred_req, handle); struct svc_xprt *xprt = dr->xprt; - if (too_many) { + spin_lock(&xprt->xpt_lock); + set_bit(XPT_DEFERRED, &xprt->xpt_flags); + if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) { + spin_unlock(&xprt->xpt_lock); + dprintk("revisit canceled\n"); svc_xprt_put(xprt); kfree(dr); return; } dprintk("revisit queued\n"); dr->xprt = NULL; - spin_lock(&xprt->xpt_lock); list_add(&dr->handle.recent, &xprt->xpt_deferred); spin_unlock(&xprt->xpt_lock); - set_bit(XPT_DEFERRED, &xprt->xpt_flags); svc_xprt_enqueue(xprt); svc_xprt_put(xprt); }