Subject: Re: [nfs-utils PATCH] sm-notify: ending the grace period early should
 be configurable
To: Scott Mayhew <smayhew@redhat.com>
References: <1489181959-2905-1-git-send-email-smayhew@redhat.com>
Cc: linux-nfs@vger.kernel.org
From: Steve Dickson <SteveD@RedHat.com>
Message-ID: <10e57187-e5be-0950-9c55-ae96faeb64e2@RedHat.com>
Date: Tue, 4 Apr 2017 13:59:57 -0400
MIME-Version: 1.0
In-Reply-To: <1489181959-2905-1-git-send-email-smayhew@redhat.com>
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Sender: linux-nfs-owner@vger.kernel.org


On 03/10/2017 04:39 PM, Scott Mayhew wrote:
> sm-notify's early ending of the grace period when it has no hosts to
> notify can cause problems in some high availability configurations,
> which may be running one sm-notify per floating IP address in the
> cluster.  This commit makes that behavior configurable via the
> nfs.conf (I don't think having a corresponding command line option
> would be particularly useful, hence none was added).
> 
> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Committed... 

steved.
> ---
>  nfs.conf                  |  1 +
>  utils/statd/sm-notify.c   |  6 +++++-
>  utils/statd/sm-notify.man | 18 ++++++++++++++++++
>  3 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/nfs.conf b/nfs.conf
> index 81ece06..690645c 100644
> --- a/nfs.conf
> +++ b/nfs.conf
> @@ -65,6 +65,7 @@
>  # retry-time=900
>  # outgoing-port=
>  # outgoing-addr=
> +# lift-grace=y
>  #
>  #[svcgssd]
>  # principal=
> diff --git a/utils/statd/sm-notify.c b/utils/statd/sm-notify.c
> index 623213e..0c6766f 100644
> --- a/utils/statd/sm-notify.c
> +++ b/utils/statd/sm-notify.c
> @@ -45,6 +45,8 @@
>  
>  #define NLM_END_GRACE_FILE	"/proc/fs/lockd/nlm_end_grace"
>  
> +int lift_grace = 1;
> +
>  struct nsm_host {
>  	struct nsm_host *	next;
>  	char *			name;
> @@ -494,6 +496,7 @@ main(int argc, char **argv)
>  	opt_max_retry = conf_get_num("sm-notify", "retry-time", opt_max_retry / 60) * 60;
>  	opt_srcport = conf_get_str("sm-notify", "outgoing-port");
>  	opt_srcaddr = conf_get_str("sm-notify", "outgoing-addr");
> +	lift_grace = conf_get_bool("sm-notify", "lift-grace", lift_grace);
>  	s = conf_get_str("statd", "state-directory-path");
>  	if (s && !nsm_setup_pathnames(argv[0], s))
>  		exit(1);
> @@ -570,7 +573,8 @@ usage:		fprintf(stderr,
>  	(void)nsm_retire_monitored_hosts();
>  	if (nsm_load_notify_list(smn_get_host) == 0) {
>  		xlog(D_GENERAL, "No hosts to notify; exiting");
> -		nsm_lift_grace_period();
> +		if (lift_grace)
> +			nsm_lift_grace_period();
>  		return 0;
>  	}
>  
> diff --git a/utils/statd/sm-notify.man b/utils/statd/sm-notify.man
> index bb7f6e0..cfe1e4b 100644
> --- a/utils/statd/sm-notify.man
> +++ b/utils/statd/sm-notify.man
> @@ -241,6 +241,24 @@ These have the same effect as the command line options
>  .B v
>  respectively.
>  
> +An additional value recognized in the
> +.B [sm-notify]
> +section is
> +.BR lift-grace .
> +By default,
> +.B sm-notify
> +will lift lockd's grace period early if it has no hosts to notify.
> +Some high availability configurations will run one
> +.B sm-notify
> +per floating IP address.  In these configurations, lifting the
> +grace period early may prevent clients from reclaiming locks.
> +.RB "Setting " lift-grace " to " n
> +will prevent
> +.B sm-notify
> +from ending the grace period early.
> +.B lift-grace
> +has no corresponding command line option.
> +
>  The value recognized in the
>  .B [statd]
>  section is
>