Return-Path: linux-nfs-owner@vger.kernel.org Received: from youngberry.canonical.com ([91.189.89.112]:33937 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757797Ab3DXU4J (ORCPT ); Wed, 24 Apr 2013 16:56:09 -0400 From: Dave Chiluk To: Trond.Myklebust@netapp.com, bfields@fieldses.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] NFSv4: Use exponential backoff delay for NFS4_ERRDELAY Date: Wed, 24 Apr 2013 15:55:49 -0500 Message-Id: <1366836949-18465-1-git-send-email-chiluk@canonical.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Changing the retry to start at NFS4_POLL_RETRY_MIN and exponentially grow to NFS4_POLL_RETRY_MAX allow for faster handling of these error conditions. Additionally this alleviates an interoperability problem with the AIX NFSv4 Server. The AIX server frequently (2 out of 3) returns NFS4ERR_DELAY, on a close when it happens in close proximity to a RELEASE_LOCKOWNER. This would cause a linux client to hang for 15 seconds. Signed-off-by: Dave Chiluk --- fs/nfs/nfs4proc.c | 12 ++++++++++++ include/linux/sunrpc/sched.h | 1 + 2 files changed, 13 insertions(+) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 0ad025e..37dad27 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -4006,6 +4006,18 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server, #endif /* CONFIG_NFS_V4_1 */ case -NFS4ERR_DELAY: nfs_inc_server_stats(server, NFSIOS_DELAY); + /* Do an exponential backoff of retries from + * NFS4_POLL_RETRY_MIN to NFS4_POLL_RETRY_MAX. */ + task->tk_timeout = NFS4_POLL_RETRY_MIN << + (task->tk_delays*2); + if (task->tk_timeout > NFS4_POLL_RETRY_MAX) + rpc_delay(task, NFS4_POLL_RETRY_MAX); + else { + task->tk_delays++; + rpc_delay(task, task->tk_timeout); + } + task->tk_status = 0; + return -EAGAIN; case -NFS4ERR_GRACE: rpc_delay(task, NFS4_POLL_RETRY_MAX); task->tk_status = 0; diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h index 84ca436..60f82bf 100644 --- a/include/linux/sunrpc/sched.h +++ b/include/linux/sunrpc/sched.h @@ -62,6 +62,7 @@ struct rpc_task { void * tk_calldata; unsigned long tk_timeout; /* timeout for rpc_sleep() */ + unsigned short tk_delays; /* number of times task delayed */ unsigned long tk_runstate; /* Task run status */ struct workqueue_struct *tk_workqueue; /* Normally rpciod, but could * be any workqueue -- 1.7.9.5