nfsd: Ensure knfsd shuts down when the "nfsd" pseudofs is unmounted

commit 00efb69c97f00587a62d961e47960675576f5aa3 upstream.

In order to ensure that knfsd threads don't linger once the nfsd
pseudofs is unmounted (e.g. when the container is killed) we let
nfsd_umount() shut down those threads and wait for them to exit.

This also should ensure that we don't need to do a kernel mount of
the pseudofs, since the thread lifetime is now limited by the
lifetime of the filesystem.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index ed53e206a29960b737cb7edc1a33da477511492e..82329b5102c696ff139558a1390fe578006b0d48 100644 (file)
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -42,9 +42,6 @@ struct nfsd_net {
        bool grace_ended;
        time_t boot_time;
 
-       /* internal mount of the "nfsd" pseudofilesystem: */
-       struct vfsmount *nfsd_mnt;
-
        struct dentry *nfsd_client_dir;
 
        /*
@@ -121,6 +118,9 @@ struct nfsd_net {
        wait_queue_head_t ntf_wq;
        atomic_t ntf_refcnt;
 
+       /* Allow umount to wait for nfsd state cleanup */
+       struct completion nfsd_shutdown_complete;
+
        /*
         * clientid and stateid data for construction of net unique COPY
         * stateids.

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index de2c3809d15aad87f2a00dff952e6616813e279b..5922eceb01762e82ebff28f1dc919b189712effc 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -7754,14 +7754,9 @@ nfs4_state_start_net(struct net *net)
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
        int ret;
 
-       ret = get_nfsdfs(net);
-       if (ret)
-               return ret;
        ret = nfs4_state_create_net(net);
-       if (ret) {
-               mntput(nn->nfsd_mnt);
+       if (ret)
                return ret;
-       }
        locks_start_grace(net, &nn->nfsd4_manager);
        nfsd4_client_tracking_init(net);
        if (nn->track_reclaim_completes && nn->reclaim_str_hashtbl_size == 0)
@@ -7830,7 +7825,6 @@ nfs4_state_shutdown_net(struct net *net)
 
        nfsd4_client_tracking_exit(net);
        nfs4_state_destroy_net(net);
-       mntput(nn->nfsd_mnt);
 }
 
 void

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 055cc0458f27075e86c1bf59b3fac80f1d4da1c8..a2454739b1cfa05b0d5171493f4ee9030fff5c10 100644 (file)
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1417,6 +1417,8 @@ static void nfsd_umount(struct super_block *sb)
 {
        struct net *net = sb->s_fs_info;
 
+       nfsd_shutdown_threads(net);
+
        kill_litter_super(sb);
        put_net(net);
 }
@@ -1429,18 +1431,6 @@ static struct file_system_type nfsd_fs_type = {
 };
 MODULE_ALIAS_FS("nfsd");
 
-int get_nfsdfs(struct net *net)
-{
-       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
-       struct vfsmount *mnt;
-
-       mnt =  vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", NULL);
-       if (IS_ERR(mnt))
-               return PTR_ERR(mnt);
-       nn->nfsd_mnt = mnt;
-       return 0;
-}
-
 #ifdef CONFIG_PROC_FS
 static int create_proc_exports_entry(void)
 {

diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 4ff0c5318a02bc3afdbc95106b98470612153848..3ae9811c0bb98020401ff2cf731bd8bd7db1c947 100644 (file)
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -84,11 +84,10 @@ int         nfsd_get_nrthreads(int n, int *, struct net *);
 int            nfsd_set_nrthreads(int n, int *, struct net *);
 int            nfsd_pool_stats_open(struct inode *, struct file *);
 int            nfsd_pool_stats_release(struct inode *, struct file *);
+void           nfsd_shutdown_threads(struct net *net);
 
 void           nfsd_destroy(struct net *net);
 
-int get_nfsdfs(struct net *);
-
 struct nfsdfs_client {
        struct kref cl_ref;
        void (*cl_release)(struct kref *kref);

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 70684c7ae94bdce7cb7aa505fbe4d531691393ab..969a227186fa8b3821995f611bc93a5e14b4e29f 100644 (file)
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -594,6 +594,37 @@ static const struct svc_serv_ops nfsd_thread_sv_ops = {
        .svo_module             = THIS_MODULE,
 };
 
+static void nfsd_complete_shutdown(struct net *net)
+{
+       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+       WARN_ON(!mutex_is_locked(&nfsd_mutex));
+
+       nn->nfsd_serv = NULL;
+       complete(&nn->nfsd_shutdown_complete);
+}
+
+void nfsd_shutdown_threads(struct net *net)
+{
+       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+       struct svc_serv *serv;
+
+       mutex_lock(&nfsd_mutex);
+       serv = nn->nfsd_serv;
+       if (serv == NULL) {
+               mutex_unlock(&nfsd_mutex);
+               return;
+       }
+
+       svc_get(serv);
+       /* Kill outstanding nfsd threads */
+       serv->sv_ops->svo_setup(serv, NULL, 0);
+       nfsd_destroy(net);
+       mutex_unlock(&nfsd_mutex);
+       /* Wait for shutdown of nfsd_serv to complete */
+       wait_for_completion(&nn->nfsd_shutdown_complete);
+}
+
 int nfsd_create_serv(struct net *net)
 {
        int error;
@@ -611,11 +642,13 @@ int nfsd_create_serv(struct net *net)
                                                &nfsd_thread_sv_ops);
        if (nn->nfsd_serv == NULL)
                return -ENOMEM;
+       init_completion(&nn->nfsd_shutdown_complete);
 
        nn->nfsd_serv->sv_maxconn = nn->max_connections;
        error = svc_bind(nn->nfsd_serv, net);
        if (error < 0) {
                svc_destroy(nn->nfsd_serv);
+               nfsd_complete_shutdown(net);
                return error;
        }
 
@@ -664,7 +697,7 @@ void nfsd_destroy(struct net *net)
                svc_shutdown_net(nn->nfsd_serv, net);
        svc_destroy(nn->nfsd_serv);
        if (destroy)
-               nn->nfsd_serv = NULL;
+               nfsd_complete_shutdown(net);
 }
 
 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)