From: Ben Myers Subject: [PATCH 3/3] nfs-utils: don't fdatasync the rmtab Date: Thu, 28 Jan 2010 15:26:39 -0600 Message-ID: <20100128212639.29681.81589.stgit@case.americas.sgi.com> References: <20100128211454.29681.24752.stgit@case.americas.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Cc: linux-nfs@vger.kernel.org To: SteveD@redhat.com Return-path: Received: from relay3.sgi.com ([192.48.152.1]:45025 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932161Ab0A1V0k (ORCPT ); Thu, 28 Jan 2010 16:26:40 -0500 In-Reply-To: <20100128211454.29681.24752.stgit-PhfrMOq4MEUPybYDWDrblq0bRtRcJeJQ@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: If we're using the new caching interface the rmtab will be ignored by exportfs so there is no need to fdatasync. This improves mountd performance. --- support/nfs/cacheio.c | 5 ++--- support/nfs/rmtab.c | 23 ++++++++++++++++++----- 2 files changed, 20 insertions(+), 8 deletions(-) diff --git a/support/nfs/cacheio.c b/support/nfs/cacheio.c index 6a6ed5a..bdf5d84 100644 --- a/support/nfs/cacheio.c +++ b/support/nfs/cacheio.c @@ -285,9 +285,8 @@ int readline(int fd, char **buf, int *lenp) int check_new_cache(void) { - struct stat stb; - return (stat("/proc/fs/nfs/filehandle", &stb) == 0) || - (stat("/proc/fs/nfsd/filehandle", &stb) == 0); + return (access("/proc/fs/nfs/filehandle", F_OK) == 0) || + (access("/proc/fs/nfsd/filehandle", F_OK) == 0); } diff --git a/support/nfs/rmtab.c b/support/nfs/rmtab.c index 4cbd285..a28abf3 100644 --- a/support/nfs/rmtab.c +++ b/support/nfs/rmtab.c @@ -117,11 +117,24 @@ void fendrmtabent(FILE *fp) { if (fp) { - /* If it was written to, we really want - * to flush to disk before returning - */ - fflush(fp); - fdatasync(fileno(fp)); + static int have_new_cache = -1; + if (have_new_cache == -1) /* check only once */ + have_new_cache = check_new_cache(); + + if (!have_new_cache) { + /* + * If we are using the old caching interface: exportfs + * uses the rmtab to determine what should be exported, + * so it is important that it be up-to-date. + * + * If we are using the new caching interface: the rmtab + * is ignored by exportfs and the fdatasync only serves + * to slow us down. + */ + fflush(fp); + fdatasync(fileno(fp)); + } + fclose(fp); } }