> On Jan 17, 2019, at 1:15 AM, ZhangXiaoxu <zhangxiaoxu5@xxxxxxxxxx> wrote:
>
> If multiple processes are locking the same file, the NSMPROC_MON
> message would be send more than one times when the host is not
> monitored by the peer.
Hi, what is the harm of sending more than one MON request for a peer?
> Add a mutex to ensure that we just send once. If some one has send
> the msg, Just waiting for the result or try again if failed.
>
> Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@xxxxxxxxxx>
> ---
> fs/lockd/mon.c | 10 ++++++++++
> include/linux/lockd/lockd.h | 1 +
> 2 files changed, 11 insertions(+)
>
> diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
> index 654594e..4ba2658 100644
> --- a/fs/lockd/mon.c
> +++ b/fs/lockd/mon.c
> @@ -155,6 +155,12 @@ int nsm_monitor(const struct nlm_host *host)
> if (nsm->sm_monitored)
> return 0;
>
> + mutex_lock(&nsm->mutex);
> + if (nsm->sm_monitored) {
> + mutex_unlock(&nsm->mutex);
> + return 0;
> + }
> +
> /*
> * Choose whether to record the caller_name or IP address of
> * this peer in the local rpc.statd's database.
> @@ -165,6 +171,7 @@ int nsm_monitor(const struct nlm_host *host)
> if (unlikely(res.status != 0))
> status = -EIO;
> if (unlikely(status < 0)) {
> + mutex_unlock(&nsm->mutex);
> pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name);
> return status;
> }
> @@ -174,6 +181,8 @@ int nsm_monitor(const struct nlm_host *host)
> nsm_local_state = res.state;
> dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
> }
> +
> + mutex_unlock(&nsm->mutex);
> return 0;
> }
>
> @@ -284,6 +293,7 @@ static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
> memcpy(nsm_addr(new), sap, salen);
> new->sm_addrlen = salen;
> nsm_init_private(new);
> + mutex_init(&new->mutex);
>
> if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,
> sizeof(new->sm_addrbuf)) == 0)
> diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
> index b065ef4..c56069c 100644
> --- a/include/linux/lockd/lockd.h
> +++ b/include/linux/lockd/lockd.h
> @@ -89,6 +89,7 @@ struct nsm_handle {
> char *sm_name;
> struct sockaddr_storage sm_addr;
> size_t sm_addrlen;
> + struct mutex mutex; /* should be send only once even more threads */
> unsigned int sm_monitored : 1,
> sm_sticky : 1; /* don't unmonitor */
> struct nsm_private sm_priv;
> --
> 2.7.4
>
--
Chuck Lever
chucklever@xxxxxxxxx
