From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f174.google.com ([209.85.220.174]:36775 "EHLO mail-qk0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752113AbbICRgb (ORCPT ); Thu, 3 Sep 2015 13:36:31 -0400 Received: by qkcf65 with SMTP id f65so24323652qkc.3 for ; Thu, 03 Sep 2015 10:36:31 -0700 (PDT) From: Jeff Layton To: steved@redhat.com Cc: bfields@fieldses.org, linux-nfs@vger.kernel.org Subject: [PATCH] exportfs: add support for "nowcc" option Date: Thu, 3 Sep 2015 13:36:25 -0400 Message-Id: <1441301785-17602-1-git-send-email-jeff.layton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: This is the userland companion patch for the patch to add a "nowcc" option to knfsd. This just adds the necessary code to allow userspace to set that option. Signed-off-by: Jeff Layton --- support/include/nfs/export.h | 3 ++- support/nfs/exports.c | 5 +++++ utils/exportfs/exportfs.c | 2 ++ utils/exportfs/exports.man | 14 ++++++++++++++ 4 files changed, 23 insertions(+), 1 deletion(-) diff --git a/support/include/nfs/export.h b/support/include/nfs/export.h index 1194255899bd..68bee5c2f305 100644 --- a/support/include/nfs/export.h +++ b/support/include/nfs/export.h @@ -26,7 +26,8 @@ #define NFSEXP_CROSSMOUNT 0x4000 #define NFSEXP_NOACL 0x8000 /* reserved for possible ACL related use */ #define NFSEXP_V4ROOT 0x10000 -#define NFSEXP_PNFS 0x20000 +#define NFSEXP_PNFS 0x20000 +#define NFSEXP_NOWCC 0x40000 /* * All flags supported by the kernel before addition of the * export_features interface: diff --git a/support/nfs/exports.c b/support/nfs/exports.c index 0aea6f154f09..791b5f756c9c 100644 --- a/support/nfs/exports.c +++ b/support/nfs/exports.c @@ -276,6 +276,7 @@ putexportent(struct exportent *ep) if (ep->e_flags & NFSEXP_NOREADDIRPLUS) fprintf(fp, "nordirplus,"); fprintf(fp, "%spnfs,", (ep->e_flags & NFSEXP_PNFS)? "" : "no_"); + fprintf(fp, "%swcc,", (ep->e_flags & NFSEXP_NOWCC) ? "no" : ""); if (ep->e_flags & NFSEXP_FSID) { fprintf(fp, "fsid=%d,", ep->e_fsid); } @@ -586,6 +587,10 @@ parseopts(char *cp, struct exportent *ep, int warn, int *had_subtree_opt_ptr) setflags(NFSEXP_PNFS, active, ep); else if (!strcmp(opt, "no_pnfs")) clearflags(NFSEXP_PNFS, active, ep); + else if (!strcmp(opt, "wcc")) + clearflags(NFSEXP_NOWCC, active, ep); + else if (!strcmp(opt, "nowcc")) + setflags(NFSEXP_NOWCC, active, ep); else if (strncmp(opt, "anonuid=", 8) == 0) { char *oe; ep->e_anonuid = strtol(opt+8, &oe, 10); diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c index 87582316b086..a2afc80ee6ea 100644 --- a/utils/exportfs/exportfs.c +++ b/utils/exportfs/exportfs.c @@ -823,6 +823,8 @@ dump(int verbose, int export_format) c = dumpopt(c, "no_acl"); if (ep->e_flags & NFSEXP_PNFS) c = dumpopt(c, "pnfs"); + if (ep->e_flags & NFSEXP_NOWCC) + c = dumpopt(c, "nowcc"); if (ep->e_flags & NFSEXP_FSID) c = dumpopt(c, "fsid=%d", ep->e_fsid); if (ep->e_uuid) diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man index 93092463153b..9213a228bb04 100644 --- a/utils/exportfs/exports.man +++ b/utils/exportfs/exports.man @@ -417,6 +417,20 @@ devices. The default can be explicitly requested with the .I no_pnfs option. +.TP +.IR nowcc +This option disables the collection and reporting of WCC (weak cache +consistency) data in NFSv3 requests. RFC 1813 recommends that all +servers report this information to the clients as it allows the client +to avoid some extra round trips to the server. In some underlying +filesystems however, collecting this data can be cost prohibitive and +atomicity is difficult to guarantee. Also, in some client use-cases WCC +data is ignored or not terribly useful. The default is to always report +weak cache consistency data to the client in NFSv3 requests, and can be +explicitly requested with the +.I wcc +option. + .SS User ID Mapping .PP .B nfsd -- 2.4.3