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

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>

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index c330f5bd0cf329f9b762deb1e36ab340c7a3daca..a75abeb1e69881295e93aa54f7e27f58d33bdfef 100644 (file)
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -51,9 +51,6 @@ struct nfsd_net {
        bool grace_ended;
        time64_t boot_time;
 
-       /* internal mount of the "nfsd" pseudofilesystem: */
-       struct vfsmount *nfsd_mnt;
-
        struct dentry *nfsd_client_dir;
 
        /*
@@ -130,6 +127,9 @@ 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 1aa7d4ee7c15aed98633dcd90c0cba92633ab790..e011b407d00741f71f505b732b7c6f7527f061dd 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -7326,14 +7326,9 @@ 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)
@@ -7403,7 +7398,6 @@ 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 ef86ed23af8281e48f5b3219436a65836935fca0..02ff7f762e2d2a8bdf7d66a10faa340f24199fbe 100644 (file)
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1416,6 +1416,8 @@ 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);
 }
@@ -1428,18 +1430,6 @@ 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 8bdc37aa2c2e4c80b4d2bba65dc4dad8b0be6488..27c1308ffc2ba6414ccc742141e72ce3f0e4d121 100644 (file)
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -93,13 +93,12 @@ 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);
 
 bool           i_am_nfsd(void);
 
-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 d909e4956244aba37c02665c81e4c3637fed25f1..b2eef4112bc27a7a80f524dfb248d03bd35b12a8 100644 (file)
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -596,6 +596,37 @@ 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);
+}
+
 bool i_am_nfsd(void)
 {
        return kthread_func(current) == nfsd;
@@ -618,11 +649,13 @@ 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;
        }
 
@@ -671,7 +704,7 @@ 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)