From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:10295 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751092Ab2CGUxE (ORCPT ); Wed, 7 Mar 2012 15:53:04 -0500 Message-ID: <4F57CAB4.2050500@RedHat.com> Date: Wed, 07 Mar 2012 15:53:08 -0500 From: Steve Dickson MIME-Version: 1.0 To: "J. Bruce Fields" CC: Linux NFS Mailing list Subject: Re: [PATCH 1/1] exportfs: Stop racing exportfs on clusters References: <1331150190-18401-1-git-send-email-steved@redhat.com> <20120307203649.GA582@fieldses.org> In-Reply-To: <20120307203649.GA582@fieldses.org> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 03/07/2012 03:36 PM, J. Bruce Fields wrote: > On Wed, Mar 07, 2012 at 02:56:30PM -0500, Steve Dickson wrote: >> This problem can occur when multiple cluster services fail over >> at the same time, causing missing high-available exports. >> Having a lot of nfs-exports will trigger this issue easier. > > Isn't the locking in support/export/xtab.c supposed to take care of > this? > > I may be confused--I forget what all these files are for.... hmm... your right... those do take out flock()s during I/O.. There must be a hole somewhere they can get corrupted... steved. > > --b. > >> >> Signed-off-by: Steve Dickson >> --- >> support/include/exportfs.h | 4 ++++ >> utils/exportfs/exportfs.c | 24 ++++++++++++++++++++++++ >> 2 files changed, 28 insertions(+), 0 deletions(-) >> >> diff --git a/support/include/exportfs.h b/support/include/exportfs.h >> index 01e87dd..99916e5 100644 >> --- a/support/include/exportfs.h >> +++ b/support/include/exportfs.h >> @@ -32,6 +32,10 @@ enum { >> FSLOC_STUB >> }; >> >> +#ifndef EXP_LOCKFILE >> +#define EXP_LOCKFILE "/var/lib/nfs/export-lock" >> +#endif >> + >> typedef struct mclient { >> struct mclient * m_next; >> char * m_hostname; >> diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c >> index 7432a65..769d438 100644 >> --- a/utils/exportfs/exportfs.c >> +++ b/utils/exportfs/exportfs.c >> @@ -16,6 +16,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -44,6 +45,23 @@ static void validate_export(nfs_export *exp); >> static int matchhostname(const char *hostname1, const char *hostname2); >> static void export_d_read(const char *dname); >> >> +static const char *lockfile = EXP_LOCKFILE; >> +static int _lockfd = -1; >> + >> +void >> +grab_lockfile() >> +{ >> + _lockfd = open(lockfile, O_CREAT|O_RDWR, 0666); >> + if (_lockfd != -1) >> + lockf(_lockfd, F_LOCK, 0); >> +} >> +void >> +release_lockfile() >> +{ >> + if (_lockfd != -1) >> + lockf(_lockfd, F_ULOCK, 0); >> +} >> + >> int >> main(int argc, char **argv) >> { >> @@ -129,6 +147,12 @@ main(int argc, char **argv) >> return 0; >> } >> } >> + /* >> + * Serialize things as best we can >> + */ >> + grab_lockfile(); >> + atexit(release_lockfile); >> + >> if (f_export && ! f_ignore) { >> export_read(_PATH_EXPORTS); >> export_d_read(_PATH_EXPORTS_D); >> -- >> 1.7.7.6 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html