diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index a75abeb1e698..935c1028c217 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -176,6 +176,12 @@ struct nfsd_net {
 	unsigned int             longest_chain_cachesize;
 
 	struct shrinker		nfsd_reply_cache_shrinker;
+
+	/* tracking server-to-server copy mounts */
+	spinlock_t              nfsd_ssc_lock;
+	struct list_head        nfsd_ssc_mount_list;
+	wait_queue_head_t       nfsd_ssc_waitq;
+
 	/* utsname taken from the process that starts the server */
 	char			nfsd_name[UNX_MAXNODENAME+1];
 };
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index f4ce93d7f26e..bc373e5a6014 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -55,6 +55,13 @@ module_param(inter_copy_offload_enable, bool, 0644);
 MODULE_PARM_DESC(inter_copy_offload_enable,
 		 "Enable inter server to server copy offload. Default: false");
 
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+static int nfsd4_ssc_umount_timeout = 900000;		/* default to 15 mins */
+module_param(nfsd4_ssc_umount_timeout, int, 0644);
+MODULE_PARM_DESC(nfsd4_ssc_umount_timeout,
+		"idle msecs before unmount export from source server");
+#endif
+
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 #include <linux/security.h>
 
@@ -1166,6 +1173,81 @@ extern void nfs_sb_deactive(struct super_block *sb);
 #define NFSD42_INTERSSC_MOUNTOPS "vers=4.2,addr=%s,sec=sys"
 
 /*
+ * setup a work entry in the ssc delayed unmount list.
+ */
+static int nfsd4_ssc_setup_dul(struct nfsd_net *nn, char *ipaddr,
+		struct nfsd4_ssc_umount_item **retwork, struct vfsmount **ss_mnt)
+{
+	struct nfsd4_ssc_umount_item *ni = 0;
+	struct nfsd4_ssc_umount_item *work = NULL;
+	struct nfsd4_ssc_umount_item *tmp;
+	DEFINE_WAIT(wait);
+
+	*ss_mnt = NULL;
+	*retwork = NULL;
+	work = kzalloc(sizeof(*work), GFP_KERNEL);
+try_again:
+	spin_lock(&nn->nfsd_ssc_lock);
+	list_for_each_entry_safe(ni, tmp, &nn->nfsd_ssc_mount_list, nsui_list) {
+		if (strncmp(ni->nsui_ipaddr, ipaddr, sizeof(ni->nsui_ipaddr)))
+			continue;
+		/* found a match */
+		if (ni->nsui_busy) {
+			/*  wait - and try again */
+			prepare_to_wait(&nn->nfsd_ssc_waitq, &wait,
+				TASK_INTERRUPTIBLE);
+			spin_unlock(&nn->nfsd_ssc_lock);
+
+			/* allow 20secs for mount/unmount for now - revisit */
+			if (signal_pending(current) ||
+					(schedule_timeout(20*HZ) == 0)) {
+				kfree(work);
+				return nfserr_eagain;
+			}
+			finish_wait(&nn->nfsd_ssc_waitq, &wait);
+			goto try_again;
+		}
+		*ss_mnt = ni->nsui_vfsmount;
+		refcount_inc(&ni->nsui_refcnt);
+		spin_unlock(&nn->nfsd_ssc_lock);
+		kfree(work);
+
+		/* return vfsmount in ss_mnt */
+		return 0;
+	}
+	if (work) {
+		strncpy(work->nsui_ipaddr, ipaddr, sizeof(work->nsui_ipaddr));
+		refcount_set(&work->nsui_refcnt, 2);
+		work->nsui_busy = true;
+		list_add_tail(&work->nsui_list, &nn->nfsd_ssc_mount_list);
+		*retwork = work;
+	}
+	spin_unlock(&nn->nfsd_ssc_lock);
+	return 0;
+}
+
+static void nfsd4_ssc_update_dul_work(struct nfsd_net *nn,
+		struct nfsd4_ssc_umount_item *work, struct vfsmount *ss_mnt)
+{
+	/* set nsui_vfsmount, clear busy flag and wakeup waiters */
+	spin_lock(&nn->nfsd_ssc_lock);
+	work->nsui_vfsmount = ss_mnt;
+	work->nsui_busy = false;
+	wake_up_all(&nn->nfsd_ssc_waitq);
+	spin_unlock(&nn->nfsd_ssc_lock);
+}
+
+static void nfsd4_ssc_cancel_dul_work(struct nfsd_net *nn,
+		struct nfsd4_ssc_umount_item *work)
+{
+	spin_lock(&nn->nfsd_ssc_lock);
+	list_del(&work->nsui_list);
+	wake_up_all(&nn->nfsd_ssc_waitq);
+	spin_unlock(&nn->nfsd_ssc_lock);
+	kfree(work);
+}
+
+/*
  * Support one copy source server for now.
  */
 static __be32
@@ -1181,6 +1263,8 @@ nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
 	char *ipaddr, *dev_name, *raw_data;
 	int len, raw_len;
 	__be32 status = nfserr_inval;
+	struct nfsd4_ssc_umount_item *work = NULL;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 
 	naddr = &nss->u.nl4_addr;
 	tmp_addrlen = rpc_uaddr2sockaddr(SVC_NET(rqstp), naddr->addr,
@@ -1229,12 +1313,23 @@ nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
 		goto out_free_rawdata;
 	snprintf(dev_name, len + 5, "%s%s%s:/", startsep, ipaddr, endsep);
 
+	status = nfsd4_ssc_setup_dul(nn, ipaddr, &work, &ss_mnt);
+	if (status)
+		goto out_free_devname;
+	if (ss_mnt)
+		goto out_done;
+
 	/* Use an 'internal' mount: SB_KERNMOUNT -> MNT_INTERNAL */
 	ss_mnt = vfs_kern_mount(type, SB_KERNMOUNT, dev_name, raw_data);
 	module_put(type->owner);
-	if (IS_ERR(ss_mnt))
+	if (IS_ERR(ss_mnt)) {
+		if (work)
+			nfsd4_ssc_cancel_dul_work(nn, work);
 		goto out_free_devname;
-
+	}
+	if (work)
+		nfsd4_ssc_update_dul_work(nn, work, ss_mnt);
+out_done:
 	status = 0;
 	*mount = ss_mnt;
 
@@ -1301,10 +1396,42 @@ static void
 nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct nfsd_file *src,
 			struct nfsd_file *dst)
 {
+	bool found = false;
+	long timeout;
+	struct nfsd4_ssc_umount_item *tmp;
+	struct nfsd4_ssc_umount_item *ni = 0;
+	struct nfsd_net *nn = net_generic(dst->nf_net, nfsd_net_id);
+
 	nfs42_ssc_close(src->nf_file);
-	fput(src->nf_file);
 	nfsd_file_put(dst);
-	mntput(ss_mnt);
+	fput(src->nf_file);
+
+	if (!nn) {
+		mntput(ss_mnt);
+		return;
+	}
+	spin_lock(&nn->nfsd_ssc_lock);
+	timeout = msecs_to_jiffies(nfsd4_ssc_umount_timeout);
+	list_for_each_entry_safe(ni, tmp, &nn->nfsd_ssc_mount_list, nsui_list) {
+		if (ni->nsui_vfsmount->mnt_sb == ss_mnt->mnt_sb) {
+			list_del(&ni->nsui_list);
+			/*
+			 * vfsmount can be shared by multiple exports,
+			 * decrement refcnt. If the count drops to 1 it
+			 * will be unmounted when nsui_expire expires.
+			 */
+			refcount_dec(&ni->nsui_refcnt);
+			ni->nsui_expire = jiffies + timeout;
+			list_add_tail(&ni->nsui_list, &nn->nfsd_ssc_mount_list);
+			found = true;
+			break;
+		}
+	}
+	spin_unlock(&nn->nfsd_ssc_lock);
+	if (!found) {
+		mntput(ss_mnt);
+		return;
+	}
 }
 
 #else /* CONFIG_NFSD_V4_2_INTER_SSC */
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b517a8794400..2484b59a3c29 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -44,6 +44,7 @@
 #include <linux/jhash.h>
 #include <linux/string_helpers.h>
 #include <linux/fsnotify.h>
+#include <linux/nfs_ssc.h>
 #include "xdr4.h"
 #include "xdr4cb.h"
 #include "vfs.h"
@@ -5457,6 +5458,69 @@ static bool state_expired(struct laundry_time *lt, time64_t last_refresh)
 	return false;
 }
 
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+void nfsd4_ssc_init_umount_work(struct nfsd_net *nn)
+{
+	spin_lock_init(&nn->nfsd_ssc_lock);
+	INIT_LIST_HEAD(&nn->nfsd_ssc_mount_list);
+	init_waitqueue_head(&nn->nfsd_ssc_waitq);
+}
+EXPORT_SYMBOL_GPL(nfsd4_ssc_init_umount_work);
+
+/*
+ * This is called when nfsd is being shutdown, after all inter_ssc
+ * cleanup were done, to destroy the ssc delayed unmount list.
+ */
+static void nfsd4_ssc_shutdown_umount(struct nfsd_net *nn)
+{
+	struct nfsd4_ssc_umount_item *ni = 0;
+	struct nfsd4_ssc_umount_item *tmp;
+
+	spin_lock(&nn->nfsd_ssc_lock);
+	list_for_each_entry_safe(ni, tmp, &nn->nfsd_ssc_mount_list, nsui_list) {
+		list_del(&ni->nsui_list);
+		spin_unlock(&nn->nfsd_ssc_lock);
+		mntput(ni->nsui_vfsmount);
+		kfree(ni);
+		spin_lock(&nn->nfsd_ssc_lock);
+	}
+	spin_unlock(&nn->nfsd_ssc_lock);
+}
+
+static void nfsd4_ssc_expire_umount(struct nfsd_net *nn)
+{
+	bool do_wakeup = false;
+	struct nfsd4_ssc_umount_item *ni = 0;
+	struct nfsd4_ssc_umount_item *tmp;
+
+	spin_lock(&nn->nfsd_ssc_lock);
+	list_for_each_entry_safe(ni, tmp, &nn->nfsd_ssc_mount_list, nsui_list) {
+		if (time_after(jiffies, ni->nsui_expire)) {
+			if (refcount_read(&ni->nsui_refcnt) > 1)
+				continue;
+
+			/* mark being unmount */
+			ni->nsui_busy = true;
+			spin_unlock(&nn->nfsd_ssc_lock);
+			mntput(ni->nsui_vfsmount);
+			spin_lock(&nn->nfsd_ssc_lock);
+
+			/* waiters need to start from begin of list */
+			list_del(&ni->nsui_list);
+			kfree(ni);
+
+			/* wakeup ssc_connect waiters */
+			do_wakeup = true;
+			continue;
+		}
+		break;
+	}
+	if (do_wakeup)
+		wake_up_all(&nn->nfsd_ssc_waitq);
+	spin_unlock(&nn->nfsd_ssc_lock);
+}
+#endif
+
 static time64_t
 nfs4_laundromat(struct nfsd_net *nn)
 {
@@ -5568,6 +5632,10 @@ nfs4_laundromat(struct nfsd_net *nn)
 		list_del_init(&nbl->nbl_lru);
 		free_blocked_lock(nbl);
 	}
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+	/* service the server-to-server copy delayed unmount list */
+	nfsd4_ssc_expire_umount(nn);
+#endif
 out:
 	return max_t(time64_t, lt.new_timeo, NFSD_LAUNDROMAT_MINTIMEOUT);
 }
@@ -7486,6 +7554,9 @@ nfs4_state_shutdown_net(struct net *net)
 
 	nfsd4_client_tracking_exit(net);
 	nfs4_state_destroy_net(net);
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+	nfsd4_ssc_shutdown_umount(nn);
+#endif
 }
 
 void
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 14dbfa75059d..9664303afdaf 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -484,6 +484,10 @@ static inline bool nfsd_attrs_supported(u32 minorversion, const u32 *bmval)
 extern int nfsd4_is_junction(struct dentry *dentry);
 extern int register_cld_notifier(void);
 extern void unregister_cld_notifier(void);
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+extern void nfsd4_ssc_init_umount_work(struct nfsd_net *nn);
+#endif
+
 #else /* CONFIG_NFSD_V4 */
 static inline int nfsd4_is_junction(struct dentry *dentry)
 {
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index dd5d69921676..ccb59e91011b 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -403,6 +403,9 @@ static int nfsd_startup_net(struct net *net, const struct cred *cred)
 	if (ret)
 		goto out_filecache;
 
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+	nfsd4_ssc_init_umount_work(nn);
+#endif
 	nn->nfsd_net_up = true;
 	return 0;
 
diff --git a/include/linux/nfs_ssc.h b/include/linux/nfs_ssc.h
index f5ba0fbff72f..222ae8883e85 100644
--- a/include/linux/nfs_ssc.h
+++ b/include/linux/nfs_ssc.h
@@ -8,6 +8,7 @@
  */
 
 #include <linux/nfs_fs.h>
+#include <linux/sunrpc/svc.h>
 
 extern struct nfs_ssc_client_ops_tbl nfs_ssc_client_tbl;
 
@@ -52,6 +53,19 @@ static inline void nfs42_ssc_close(struct file *filep)
 	if (nfs_ssc_client_tbl.ssc_nfs4_ops)
 		(*nfs_ssc_client_tbl.ssc_nfs4_ops->sco_close)(filep);
 }
+
+struct nfsd4_ssc_umount_item {
+	struct list_head nsui_list;
+	bool nsui_busy;
+	/*
+	 * nsui_refcnt inited to 2, 1 on list and 1 for consumer. Entry
+	 * is removed when refcnt drops to 1 and nsui_expire expires.
+	 */
+	refcount_t nsui_refcnt;
+	unsigned long nsui_expire;
+	struct vfsmount *nsui_vfsmount;
+	char nsui_ipaddr[RPC_MAX_ADDRBUFLEN];
+};
 #endif
 
 /*
