Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 8228 insertions, 0 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
new file mode 100644
index 000000000..faecdbfa0
--- /dev/null
+++ b/fs/nfsd/nfs4state.c
@@ -0,0 +1,8228 @@
+/*
+*  Copyright (c) 2001 The Regents of the University of Michigan.
+*  All rights reserved.
+*
+*  Kendrick Smith <kmsmith@umich.edu>
+*  Andy Adamson <kandros@umich.edu>
+*
+*  Redistribution and use in source and binary forms, with or without
+*  modification, are permitted provided that the following conditions
+*  are met:
+*
+*  1. Redistributions of source code must retain the above copyright
+*     notice, this list of conditions and the following disclaimer.
+*  2. Redistributions in binary form must reproduce the above copyright
+*     notice, this list of conditions and the following disclaimer in the
+*     documentation and/or other materials provided with the distribution.
+*  3. Neither the name of the University nor the names of its
+*     contributors may be used to endorse or promote products derived
+*     from this software without specific prior written permission.
+*
+*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+*  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+*  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+*  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+*  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+*  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+*  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+*  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+*  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+*/
+
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/namei.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
+#include <linux/ratelimit.h>
+#include <linux/sunrpc/svcauth_gss.h>
+#include <linux/sunrpc/addr.h>
+#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"
+#include "current_stateid.h"
+
+#include "netns.h"
+#include "pnfs.h"
+#include "filecache.h"
+#include "trace.h"
+
+#define NFSDDBG_FACILITY                NFSDDBG_PROC
+
+#define all_ones {{~0,~0},~0}
+static const stateid_t one_stateid = {
+	.si_generation = ~0,
+	.si_opaque = all_ones,
+};
+static const stateid_t zero_stateid = {
+	/* all fields zero */
+};
+static const stateid_t currentstateid = {
+	.si_generation = 1,
+};
+static const stateid_t close_stateid = {
+	.si_generation = 0xffffffffU,
+};
+
+static u64 current_sessionid = 1;
+
+#define ZERO_STATEID(stateid) (!memcmp((stateid), &zero_stateid, sizeof(stateid_t)))
+#define ONE_STATEID(stateid)  (!memcmp((stateid), &one_stateid, sizeof(stateid_t)))
+#define CURRENT_STATEID(stateid) (!memcmp((stateid), &currentstateid, sizeof(stateid_t)))
+#define CLOSE_STATEID(stateid)  (!memcmp((stateid), &close_stateid, sizeof(stateid_t)))
+
+/* forward declarations */
+static bool check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner);
+static void nfs4_free_ol_stateid(struct nfs4_stid *stid);
+void nfsd4_end_grace(struct nfsd_net *nn);
+static void _free_cpntf_state_locked(struct nfsd_net *nn, struct nfs4_cpntf_state *cps);
+
+/* Locking: */
+
+/*
+ * Currently used for the del_recall_lru and file hash table.  In an
+ * effort to decrease the scope of the client_mutex, this spinlock may
+ * eventually cover more:
+ */
+static DEFINE_SPINLOCK(state_lock);
+
+enum nfsd4_st_mutex_lock_subclass {
+	OPEN_STATEID_MUTEX = 0,
+	LOCK_STATEID_MUTEX = 1,
+};
+
+/*
+ * A waitqueue for all in-progress 4.0 CLOSE operations that are waiting for
+ * the refcount on the open stateid to drop.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(close_wq);
+
+/*
+ * A waitqueue where a writer to clients/#/ctl destroying a client can
+ * wait for cl_rpc_users to drop to 0 and then for the client to be
+ * unhashed.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(expiry_wq);
+
+static struct kmem_cache *client_slab;
+static struct kmem_cache *openowner_slab;
+static struct kmem_cache *lockowner_slab;
+static struct kmem_cache *file_slab;
+static struct kmem_cache *stateid_slab;
+static struct kmem_cache *deleg_slab;
+static struct kmem_cache *odstate_slab;
+
+static void free_session(struct nfsd4_session *);
+
+static const struct nfsd4_callback_ops nfsd4_cb_recall_ops;
+static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops;
+
+static struct workqueue_struct *laundry_wq;
+
+int nfsd4_create_laundry_wq(void)
+{
+	int rc = 0;
+
+	laundry_wq = alloc_workqueue("%s", WQ_UNBOUND, 0, "nfsd4");
+	if (laundry_wq == NULL)
+		rc = -ENOMEM;
+	return rc;
+}
+
+void nfsd4_destroy_laundry_wq(void)
+{
+	destroy_workqueue(laundry_wq);
+}
+
+static bool is_session_dead(struct nfsd4_session *ses)
+{
+	return ses->se_flags & NFS4_SESSION_DEAD;
+}
+
+static __be32 mark_session_dead_locked(struct nfsd4_session *ses, int ref_held_by_me)
+{
+	if (atomic_read(&ses->se_ref) > ref_held_by_me)
+		return nfserr_jukebox;
+	ses->se_flags |= NFS4_SESSION_DEAD;
+	return nfs_ok;
+}
+
+static bool is_client_expired(struct nfs4_client *clp)
+{
+	return clp->cl_time == 0;
+}
+
+static void nfsd4_dec_courtesy_client_count(struct nfsd_net *nn,
+					struct nfs4_client *clp)
+{
+	if (clp->cl_state != NFSD4_ACTIVE)
+		atomic_add_unless(&nn->nfsd_courtesy_clients, -1, 0);
+}
+
+static __be32 get_client_locked(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	lockdep_assert_held(&nn->client_lock);
+
+	if (is_client_expired(clp))
+		return nfserr_expired;
+	atomic_inc(&clp->cl_rpc_users);
+	nfsd4_dec_courtesy_client_count(nn, clp);
+	clp->cl_state = NFSD4_ACTIVE;
+	return nfs_ok;
+}
+
+/* must be called under the client_lock */
+static inline void
+renew_client_locked(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	if (is_client_expired(clp)) {
+		WARN_ON(1);
+		printk("%s: client (clientid %08x/%08x) already expired\n",
+			__func__,
+			clp->cl_clientid.cl_boot,
+			clp->cl_clientid.cl_id);
+		return;
+	}
+
+	list_move_tail(&clp->cl_lru, &nn->client_lru);
+	clp->cl_time = ktime_get_boottime_seconds();
+	nfsd4_dec_courtesy_client_count(nn, clp);
+	clp->cl_state = NFSD4_ACTIVE;
+}
+
+static void put_client_renew_locked(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	lockdep_assert_held(&nn->client_lock);
+
+	if (!atomic_dec_and_test(&clp->cl_rpc_users))
+		return;
+	if (!is_client_expired(clp))
+		renew_client_locked(clp);
+	else
+		wake_up_all(&expiry_wq);
+}
+
+static void put_client_renew(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	if (!atomic_dec_and_lock(&clp->cl_rpc_users, &nn->client_lock))
+		return;
+	if (!is_client_expired(clp))
+		renew_client_locked(clp);
+	else
+		wake_up_all(&expiry_wq);
+	spin_unlock(&nn->client_lock);
+}
+
+static __be32 nfsd4_get_session_locked(struct nfsd4_session *ses)
+{
+	__be32 status;
+
+	if (is_session_dead(ses))
+		return nfserr_badsession;
+	status = get_client_locked(ses->se_client);
+	if (status)
+		return status;
+	atomic_inc(&ses->se_ref);
+	return nfs_ok;
+}
+
+static void nfsd4_put_session_locked(struct nfsd4_session *ses)
+{
+	struct nfs4_client *clp = ses->se_client;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	lockdep_assert_held(&nn->client_lock);
+
+	if (atomic_dec_and_test(&ses->se_ref) && is_session_dead(ses))
+		free_session(ses);
+	put_client_renew_locked(clp);
+}
+
+static void nfsd4_put_session(struct nfsd4_session *ses)
+{
+	struct nfs4_client *clp = ses->se_client;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	spin_lock(&nn->client_lock);
+	nfsd4_put_session_locked(ses);
+	spin_unlock(&nn->client_lock);
+}
+
+static struct nfsd4_blocked_lock *
+find_blocked_lock(struct nfs4_lockowner *lo, struct knfsd_fh *fh,
+			struct nfsd_net *nn)
+{
+	struct nfsd4_blocked_lock *cur, *found = NULL;
+
+	spin_lock(&nn->blocked_locks_lock);
+	list_for_each_entry(cur, &lo->lo_blocked, nbl_list) {
+		if (fh_match(fh, &cur->nbl_fh)) {
+			list_del_init(&cur->nbl_list);
+			WARN_ON(list_empty(&cur->nbl_lru));
+			list_del_init(&cur->nbl_lru);
+			found = cur;
+			break;
+		}
+	}
+	spin_unlock(&nn->blocked_locks_lock);
+	if (found)
+		locks_delete_block(&found->nbl_lock);
+	return found;
+}
+
+static struct nfsd4_blocked_lock *
+find_or_allocate_block(struct nfs4_lockowner *lo, struct knfsd_fh *fh,
+			struct nfsd_net *nn)
+{
+	struct nfsd4_blocked_lock *nbl;
+
+	nbl = find_blocked_lock(lo, fh, nn);
+	if (!nbl) {
+		nbl= kmalloc(sizeof(*nbl), GFP_KERNEL);
+		if (nbl) {
+			INIT_LIST_HEAD(&nbl->nbl_list);
+			INIT_LIST_HEAD(&nbl->nbl_lru);
+			fh_copy_shallow(&nbl->nbl_fh, fh);
+			locks_init_lock(&nbl->nbl_lock);
+			kref_init(&nbl->nbl_kref);
+			nfsd4_init_cb(&nbl->nbl_cb, lo->lo_owner.so_client,
+					&nfsd4_cb_notify_lock_ops,
+					NFSPROC4_CLNT_CB_NOTIFY_LOCK);
+		}
+	}
+	return nbl;
+}
+
+static void
+free_nbl(struct kref *kref)
+{
+	struct nfsd4_blocked_lock *nbl;
+
+	nbl = container_of(kref, struct nfsd4_blocked_lock, nbl_kref);
+	kfree(nbl);
+}
+
+static void
+free_blocked_lock(struct nfsd4_blocked_lock *nbl)
+{
+	locks_delete_block(&nbl->nbl_lock);
+	locks_release_private(&nbl->nbl_lock);
+	kref_put(&nbl->nbl_kref, free_nbl);
+}
+
+static void
+remove_blocked_locks(struct nfs4_lockowner *lo)
+{
+	struct nfs4_client *clp = lo->lo_owner.so_client;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct nfsd4_blocked_lock *nbl;
+	LIST_HEAD(reaplist);
+
+	/* Dequeue all blocked locks */
+	spin_lock(&nn->blocked_locks_lock);
+	while (!list_empty(&lo->lo_blocked)) {
+		nbl = list_first_entry(&lo->lo_blocked,
+					struct nfsd4_blocked_lock,
+					nbl_list);
+		list_del_init(&nbl->nbl_list);
+		WARN_ON(list_empty(&nbl->nbl_lru));
+		list_move(&nbl->nbl_lru, &reaplist);
+	}
+	spin_unlock(&nn->blocked_locks_lock);
+
+	/* Now free them */
+	while (!list_empty(&reaplist)) {
+		nbl = list_first_entry(&reaplist, struct nfsd4_blocked_lock,
+					nbl_lru);
+		list_del_init(&nbl->nbl_lru);
+		free_blocked_lock(nbl);
+	}
+}
+
+static void
+nfsd4_cb_notify_lock_prepare(struct nfsd4_callback *cb)
+{
+	struct nfsd4_blocked_lock	*nbl = container_of(cb,
+						struct nfsd4_blocked_lock, nbl_cb);
+	locks_delete_block(&nbl->nbl_lock);
+}
+
+static int
+nfsd4_cb_notify_lock_done(struct nfsd4_callback *cb, struct rpc_task *task)
+{
+	trace_nfsd_cb_notify_lock_done(&zero_stateid, task);
+
+	/*
+	 * Since this is just an optimization, we don't try very hard if it
+	 * turns out not to succeed. We'll requeue it on NFS4ERR_DELAY, and
+	 * just quit trying on anything else.
+	 */
+	switch (task->tk_status) {
+	case -NFS4ERR_DELAY:
+		rpc_delay(task, 1 * HZ);
+		return 0;
+	default:
+		return 1;
+	}
+}
+
+static void
+nfsd4_cb_notify_lock_release(struct nfsd4_callback *cb)
+{
+	struct nfsd4_blocked_lock	*nbl = container_of(cb,
+						struct nfsd4_blocked_lock, nbl_cb);
+
+	free_blocked_lock(nbl);
+}
+
+static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = {
+	.prepare	= nfsd4_cb_notify_lock_prepare,
+	.done		= nfsd4_cb_notify_lock_done,
+	.release	= nfsd4_cb_notify_lock_release,
+};
+
+/*
+ * We store the NONE, READ, WRITE, and BOTH bits separately in the
+ * st_{access,deny}_bmap field of the stateid, in order to track not
+ * only what share bits are currently in force, but also what
+ * combinations of share bits previous opens have used.  This allows us
+ * to enforce the recommendation in
+ * https://datatracker.ietf.org/doc/html/rfc7530#section-16.19.4 that
+ * the server return an error if the client attempt to downgrade to a
+ * combination of share bits not explicable by closing some of its
+ * previous opens.
+ *
+ * This enforcement is arguably incomplete, since we don't keep
+ * track of access/deny bit combinations; so, e.g., we allow:
+ *
+ *	OPEN allow read, deny write
+ *	OPEN allow both, deny none
+ *	DOWNGRADE allow read, deny none
+ *
+ * which we should reject.
+ *
+ * But you could also argue that our current code is already overkill,
+ * since it only exists to return NFS4ERR_INVAL on incorrect client
+ * behavior.
+ */
+static unsigned int
+bmap_to_share_mode(unsigned long bmap)
+{
+	int i;
+	unsigned int access = 0;
+
+	for (i = 1; i < 4; i++) {
+		if (test_bit(i, &bmap))
+			access |= i;
+	}
+	return access;
+}
+
+/* set share access for a given stateid */
+static inline void
+set_access(u32 access, struct nfs4_ol_stateid *stp)
+{
+	unsigned char mask = 1 << access;
+
+	WARN_ON_ONCE(access > NFS4_SHARE_ACCESS_BOTH);
+	stp->st_access_bmap |= mask;
+}
+
+/* clear share access for a given stateid */
+static inline void
+clear_access(u32 access, struct nfs4_ol_stateid *stp)
+{
+	unsigned char mask = 1 << access;
+
+	WARN_ON_ONCE(access > NFS4_SHARE_ACCESS_BOTH);
+	stp->st_access_bmap &= ~mask;
+}
+
+/* test whether a given stateid has access */
+static inline bool
+test_access(u32 access, struct nfs4_ol_stateid *stp)
+{
+	unsigned char mask = 1 << access;
+
+	return (bool)(stp->st_access_bmap & mask);
+}
+
+/* set share deny for a given stateid */
+static inline void
+set_deny(u32 deny, struct nfs4_ol_stateid *stp)
+{
+	unsigned char mask = 1 << deny;
+
+	WARN_ON_ONCE(deny > NFS4_SHARE_DENY_BOTH);
+	stp->st_deny_bmap |= mask;
+}
+
+/* clear share deny for a given stateid */
+static inline void
+clear_deny(u32 deny, struct nfs4_ol_stateid *stp)
+{
+	unsigned char mask = 1 << deny;
+
+	WARN_ON_ONCE(deny > NFS4_SHARE_DENY_BOTH);
+	stp->st_deny_bmap &= ~mask;
+}
+
+/* test whether a given stateid is denying specific access */
+static inline bool
+test_deny(u32 deny, struct nfs4_ol_stateid *stp)
+{
+	unsigned char mask = 1 << deny;
+
+	return (bool)(stp->st_deny_bmap & mask);
+}
+
+static int nfs4_access_to_omode(u32 access)
+{
+	switch (access & NFS4_SHARE_ACCESS_BOTH) {
+	case NFS4_SHARE_ACCESS_READ:
+		return O_RDONLY;
+	case NFS4_SHARE_ACCESS_WRITE:
+		return O_WRONLY;
+	case NFS4_SHARE_ACCESS_BOTH:
+		return O_RDWR;
+	}
+	WARN_ON_ONCE(1);
+	return O_RDONLY;
+}
+
+static inline int
+access_permit_read(struct nfs4_ol_stateid *stp)
+{
+	return test_access(NFS4_SHARE_ACCESS_READ, stp) ||
+		test_access(NFS4_SHARE_ACCESS_BOTH, stp) ||
+		test_access(NFS4_SHARE_ACCESS_WRITE, stp);
+}
+
+static inline int
+access_permit_write(struct nfs4_ol_stateid *stp)
+{
+	return test_access(NFS4_SHARE_ACCESS_WRITE, stp) ||
+		test_access(NFS4_SHARE_ACCESS_BOTH, stp);
+}
+
+static inline struct nfs4_stateowner *
+nfs4_get_stateowner(struct nfs4_stateowner *sop)
+{
+	atomic_inc(&sop->so_count);
+	return sop;
+}
+
+static int
+same_owner_str(struct nfs4_stateowner *sop, struct xdr_netobj *owner)
+{
+	return (sop->so_owner.len == owner->len) &&
+		0 == memcmp(sop->so_owner.data, owner->data, owner->len);
+}
+
+static struct nfs4_openowner *
+find_openstateowner_str_locked(unsigned int hashval, struct nfsd4_open *open,
+			struct nfs4_client *clp)
+{
+	struct nfs4_stateowner *so;
+
+	lockdep_assert_held(&clp->cl_lock);
+
+	list_for_each_entry(so, &clp->cl_ownerstr_hashtbl[hashval],
+			    so_strhash) {
+		if (!so->so_is_open_owner)
+			continue;
+		if (same_owner_str(so, &open->op_owner))
+			return openowner(nfs4_get_stateowner(so));
+	}
+	return NULL;
+}
+
+static struct nfs4_openowner *
+find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open,
+			struct nfs4_client *clp)
+{
+	struct nfs4_openowner *oo;
+
+	spin_lock(&clp->cl_lock);
+	oo = find_openstateowner_str_locked(hashval, open, clp);
+	spin_unlock(&clp->cl_lock);
+	return oo;
+}
+
+static inline u32
+opaque_hashval(const void *ptr, int nbytes)
+{
+	unsigned char *cptr = (unsigned char *) ptr;
+
+	u32 x = 0;
+	while (nbytes--) {
+		x *= 37;
+		x += *cptr++;
+	}
+	return x;
+}
+
+static void nfsd4_free_file_rcu(struct rcu_head *rcu)
+{
+	struct nfs4_file *fp = container_of(rcu, struct nfs4_file, fi_rcu);
+
+	kmem_cache_free(file_slab, fp);
+}
+
+void
+put_nfs4_file(struct nfs4_file *fi)
+{
+	might_lock(&state_lock);
+
+	if (refcount_dec_and_lock(&fi->fi_ref, &state_lock)) {
+		hlist_del_rcu(&fi->fi_hash);
+		spin_unlock(&state_lock);
+		WARN_ON_ONCE(!list_empty(&fi->fi_clnt_odstate));
+		WARN_ON_ONCE(!list_empty(&fi->fi_delegations));
+		call_rcu(&fi->fi_rcu, nfsd4_free_file_rcu);
+	}
+}
+
+static struct nfsd_file *
+__nfs4_get_fd(struct nfs4_file *f, int oflag)
+{
+	if (f->fi_fds[oflag])
+		return nfsd_file_get(f->fi_fds[oflag]);
+	return NULL;
+}
+
+static struct nfsd_file *
+find_writeable_file_locked(struct nfs4_file *f)
+{
+	struct nfsd_file *ret;
+
+	lockdep_assert_held(&f->fi_lock);
+
+	ret = __nfs4_get_fd(f, O_WRONLY);
+	if (!ret)
+		ret = __nfs4_get_fd(f, O_RDWR);
+	return ret;
+}
+
+static struct nfsd_file *
+find_writeable_file(struct nfs4_file *f)
+{
+	struct nfsd_file *ret;
+
+	spin_lock(&f->fi_lock);
+	ret = find_writeable_file_locked(f);
+	spin_unlock(&f->fi_lock);
+
+	return ret;
+}
+
+static struct nfsd_file *
+find_readable_file_locked(struct nfs4_file *f)
+{
+	struct nfsd_file *ret;
+
+	lockdep_assert_held(&f->fi_lock);
+
+	ret = __nfs4_get_fd(f, O_RDONLY);
+	if (!ret)
+		ret = __nfs4_get_fd(f, O_RDWR);
+	return ret;
+}
+
+static struct nfsd_file *
+find_readable_file(struct nfs4_file *f)
+{
+	struct nfsd_file *ret;
+
+	spin_lock(&f->fi_lock);
+	ret = find_readable_file_locked(f);
+	spin_unlock(&f->fi_lock);
+
+	return ret;
+}
+
+struct nfsd_file *
+find_any_file(struct nfs4_file *f)
+{
+	struct nfsd_file *ret;
+
+	if (!f)
+		return NULL;
+	spin_lock(&f->fi_lock);
+	ret = __nfs4_get_fd(f, O_RDWR);
+	if (!ret) {
+		ret = __nfs4_get_fd(f, O_WRONLY);
+		if (!ret)
+			ret = __nfs4_get_fd(f, O_RDONLY);
+	}
+	spin_unlock(&f->fi_lock);
+	return ret;
+}
+
+static struct nfsd_file *find_any_file_locked(struct nfs4_file *f)
+{
+	lockdep_assert_held(&f->fi_lock);
+
+	if (f->fi_fds[O_RDWR])
+		return f->fi_fds[O_RDWR];
+	if (f->fi_fds[O_WRONLY])
+		return f->fi_fds[O_WRONLY];
+	if (f->fi_fds[O_RDONLY])
+		return f->fi_fds[O_RDONLY];
+	return NULL;
+}
+
+static struct nfsd_file *find_deleg_file_locked(struct nfs4_file *f)
+{
+	lockdep_assert_held(&f->fi_lock);
+
+	if (f->fi_deleg_file)
+		return f->fi_deleg_file;
+	return NULL;
+}
+
+static atomic_long_t num_delegations;
+unsigned long max_delegations;
+
+/*
+ * Open owner state (share locks)
+ */
+
+/* hash tables for lock and open owners */
+#define OWNER_HASH_BITS              8
+#define OWNER_HASH_SIZE             (1 << OWNER_HASH_BITS)
+#define OWNER_HASH_MASK             (OWNER_HASH_SIZE - 1)
+
+static unsigned int ownerstr_hashval(struct xdr_netobj *ownername)
+{
+	unsigned int ret;
+
+	ret = opaque_hashval(ownername->data, ownername->len);
+	return ret & OWNER_HASH_MASK;
+}
+
+/* hash table for nfs4_file */
+#define FILE_HASH_BITS                   8
+#define FILE_HASH_SIZE                  (1 << FILE_HASH_BITS)
+
+static unsigned int file_hashval(struct svc_fh *fh)
+{
+	struct inode *inode = d_inode(fh->fh_dentry);
+
+	/* XXX: why not (here & in file cache) use inode? */
+	return (unsigned int)hash_long(inode->i_ino, FILE_HASH_BITS);
+}
+
+static struct hlist_head file_hashtbl[FILE_HASH_SIZE];
+
+/*
+ * Check if courtesy clients have conflicting access and resolve it if possible
+ *
+ * access:  is op_share_access if share_access is true.
+ *	    Check if access mode, op_share_access, would conflict with
+ *	    the current deny mode of the file 'fp'.
+ * access:  is op_share_deny if share_access is false.
+ *	    Check if the deny mode, op_share_deny, would conflict with
+ *	    current access of the file 'fp'.
+ * stp:     skip checking this entry.
+ * new_stp: normal open, not open upgrade.
+ *
+ * Function returns:
+ *	false - access/deny mode conflict with normal client.
+ *	true  - no conflict or conflict with courtesy client(s) is resolved.
+ */
+static bool
+nfs4_resolve_deny_conflicts_locked(struct nfs4_file *fp, bool new_stp,
+		struct nfs4_ol_stateid *stp, u32 access, bool share_access)
+{
+	struct nfs4_ol_stateid *st;
+	bool resolvable = true;
+	unsigned char bmap;
+	struct nfsd_net *nn;
+	struct nfs4_client *clp;
+
+	lockdep_assert_held(&fp->fi_lock);
+	list_for_each_entry(st, &fp->fi_stateids, st_perfile) {
+		/* ignore lock stateid */
+		if (st->st_openstp)
+			continue;
+		if (st == stp && new_stp)
+			continue;
+		/* check file access against deny mode or vice versa */
+		bmap = share_access ? st->st_deny_bmap : st->st_access_bmap;
+		if (!(access & bmap_to_share_mode(bmap)))
+			continue;
+		clp = st->st_stid.sc_client;
+		if (try_to_expire_client(clp))
+			continue;
+		resolvable = false;
+		break;
+	}
+	if (resolvable) {
+		clp = stp->st_stid.sc_client;
+		nn = net_generic(clp->net, nfsd_net_id);
+		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+	}
+	return resolvable;
+}
+
+static void
+__nfs4_file_get_access(struct nfs4_file *fp, u32 access)
+{
+	lockdep_assert_held(&fp->fi_lock);
+
+	if (access & NFS4_SHARE_ACCESS_WRITE)
+		atomic_inc(&fp->fi_access[O_WRONLY]);
+	if (access & NFS4_SHARE_ACCESS_READ)
+		atomic_inc(&fp->fi_access[O_RDONLY]);
+}
+
+static __be32
+nfs4_file_get_access(struct nfs4_file *fp, u32 access)
+{
+	lockdep_assert_held(&fp->fi_lock);
+
+	/* Does this access mode make sense? */
+	if (access & ~NFS4_SHARE_ACCESS_BOTH)
+		return nfserr_inval;
+
+	/* Does it conflict with a deny mode already set? */
+	if ((access & fp->fi_share_deny) != 0)
+		return nfserr_share_denied;
+
+	__nfs4_file_get_access(fp, access);
+	return nfs_ok;
+}
+
+static __be32 nfs4_file_check_deny(struct nfs4_file *fp, u32 deny)
+{
+	/* Common case is that there is no deny mode. */
+	if (deny) {
+		/* Does this deny mode make sense? */
+		if (deny & ~NFS4_SHARE_DENY_BOTH)
+			return nfserr_inval;
+
+		if ((deny & NFS4_SHARE_DENY_READ) &&
+		    atomic_read(&fp->fi_access[O_RDONLY]))
+			return nfserr_share_denied;
+
+		if ((deny & NFS4_SHARE_DENY_WRITE) &&
+		    atomic_read(&fp->fi_access[O_WRONLY]))
+			return nfserr_share_denied;
+	}
+	return nfs_ok;
+}
+
+static void __nfs4_file_put_access(struct nfs4_file *fp, int oflag)
+{
+	might_lock(&fp->fi_lock);
+
+	if (atomic_dec_and_lock(&fp->fi_access[oflag], &fp->fi_lock)) {
+		struct nfsd_file *f1 = NULL;
+		struct nfsd_file *f2 = NULL;
+
+		swap(f1, fp->fi_fds[oflag]);
+		if (atomic_read(&fp->fi_access[1 - oflag]) == 0)
+			swap(f2, fp->fi_fds[O_RDWR]);
+		spin_unlock(&fp->fi_lock);
+		if (f1)
+			nfsd_file_put(f1);
+		if (f2)
+			nfsd_file_put(f2);
+	}
+}
+
+static void nfs4_file_put_access(struct nfs4_file *fp, u32 access)
+{
+	WARN_ON_ONCE(access & ~NFS4_SHARE_ACCESS_BOTH);
+
+	if (access & NFS4_SHARE_ACCESS_WRITE)
+		__nfs4_file_put_access(fp, O_WRONLY);
+	if (access & NFS4_SHARE_ACCESS_READ)
+		__nfs4_file_put_access(fp, O_RDONLY);
+}
+
+/*
+ * Allocate a new open/delegation state counter. This is needed for
+ * pNFS for proper return on close semantics.
+ *
+ * Note that we only allocate it for pNFS-enabled exports, otherwise
+ * all pointers to struct nfs4_clnt_odstate are always NULL.
+ */
+static struct nfs4_clnt_odstate *
+alloc_clnt_odstate(struct nfs4_client *clp)
+{
+	struct nfs4_clnt_odstate *co;
+
+	co = kmem_cache_zalloc(odstate_slab, GFP_KERNEL);
+	if (co) {
+		co->co_client = clp;
+		refcount_set(&co->co_odcount, 1);
+	}
+	return co;
+}
+
+static void
+hash_clnt_odstate_locked(struct nfs4_clnt_odstate *co)
+{
+	struct nfs4_file *fp = co->co_file;
+
+	lockdep_assert_held(&fp->fi_lock);
+	list_add(&co->co_perfile, &fp->fi_clnt_odstate);
+}
+
+static inline void
+get_clnt_odstate(struct nfs4_clnt_odstate *co)
+{
+	if (co)
+		refcount_inc(&co->co_odcount);
+}
+
+static void
+put_clnt_odstate(struct nfs4_clnt_odstate *co)
+{
+	struct nfs4_file *fp;
+
+	if (!co)
+		return;
+
+	fp = co->co_file;
+	if (refcount_dec_and_lock(&co->co_odcount, &fp->fi_lock)) {
+		list_del(&co->co_perfile);
+		spin_unlock(&fp->fi_lock);
+
+		nfsd4_return_all_file_layouts(co->co_client, fp);
+		kmem_cache_free(odstate_slab, co);
+	}
+}
+
+static struct nfs4_clnt_odstate *
+find_or_hash_clnt_odstate(struct nfs4_file *fp, struct nfs4_clnt_odstate *new)
+{
+	struct nfs4_clnt_odstate *co;
+	struct nfs4_client *cl;
+
+	if (!new)
+		return NULL;
+
+	cl = new->co_client;
+
+	spin_lock(&fp->fi_lock);
+	list_for_each_entry(co, &fp->fi_clnt_odstate, co_perfile) {
+		if (co->co_client == cl) {
+			get_clnt_odstate(co);
+			goto out;
+		}
+	}
+	co = new;
+	co->co_file = fp;
+	hash_clnt_odstate_locked(new);
+out:
+	spin_unlock(&fp->fi_lock);
+	return co;
+}
+
+struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl, struct kmem_cache *slab,
+				  void (*sc_free)(struct nfs4_stid *))
+{
+	struct nfs4_stid *stid;
+	int new_id;
+
+	stid = kmem_cache_zalloc(slab, GFP_KERNEL);
+	if (!stid)
+		return NULL;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock(&cl->cl_lock);
+	/* Reserving 0 for start of file in nfsdfs "states" file: */
+	new_id = idr_alloc_cyclic(&cl->cl_stateids, stid, 1, 0, GFP_NOWAIT);
+	spin_unlock(&cl->cl_lock);
+	idr_preload_end();
+	if (new_id < 0)
+		goto out_free;
+
+	stid->sc_free = sc_free;
+	stid->sc_client = cl;
+	stid->sc_stateid.si_opaque.so_id = new_id;
+	stid->sc_stateid.si_opaque.so_clid = cl->cl_clientid;
+	/* Will be incremented before return to client: */
+	refcount_set(&stid->sc_count, 1);
+	spin_lock_init(&stid->sc_lock);
+	INIT_LIST_HEAD(&stid->sc_cp_list);
+
+	/*
+	 * It shouldn't be a problem to reuse an opaque stateid value.
+	 * I don't think it is for 4.1.  But with 4.0 I worry that, for
+	 * example, a stray write retransmission could be accepted by
+	 * the server when it should have been rejected.  Therefore,
+	 * adopt a trick from the sctp code to attempt to maximize the
+	 * amount of time until an id is reused, by ensuring they always
+	 * "increase" (mod INT_MAX):
+	 */
+	return stid;
+out_free:
+	kmem_cache_free(slab, stid);
+	return NULL;
+}
+
+/*
+ * Create a unique stateid_t to represent each COPY.
+ */
+static int nfs4_init_cp_state(struct nfsd_net *nn, copy_stateid_t *stid,
+			      unsigned char cs_type)
+{
+	int new_id;
+
+	stid->cs_stid.si_opaque.so_clid.cl_boot = (u32)nn->boot_time;
+	stid->cs_stid.si_opaque.so_clid.cl_id = nn->s2s_cp_cl_id;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock(&nn->s2s_cp_lock);
+	new_id = idr_alloc_cyclic(&nn->s2s_cp_stateids, stid, 0, 0, GFP_NOWAIT);
+	stid->cs_stid.si_opaque.so_id = new_id;
+	stid->cs_stid.si_generation = 1;
+	spin_unlock(&nn->s2s_cp_lock);
+	idr_preload_end();
+	if (new_id < 0)
+		return 0;
+	stid->cs_type = cs_type;
+	return 1;
+}
+
+int nfs4_init_copy_state(struct nfsd_net *nn, struct nfsd4_copy *copy)
+{
+	return nfs4_init_cp_state(nn, &copy->cp_stateid, NFS4_COPY_STID);
+}
+
+struct nfs4_cpntf_state *nfs4_alloc_init_cpntf_state(struct nfsd_net *nn,
+						     struct nfs4_stid *p_stid)
+{
+	struct nfs4_cpntf_state *cps;
+
+	cps = kzalloc(sizeof(struct nfs4_cpntf_state), GFP_KERNEL);
+	if (!cps)
+		return NULL;
+	cps->cpntf_time = ktime_get_boottime_seconds();
+	refcount_set(&cps->cp_stateid.cs_count, 1);
+	if (!nfs4_init_cp_state(nn, &cps->cp_stateid, NFS4_COPYNOTIFY_STID))
+		goto out_free;
+	spin_lock(&nn->s2s_cp_lock);
+	list_add(&cps->cp_list, &p_stid->sc_cp_list);
+	spin_unlock(&nn->s2s_cp_lock);
+	return cps;
+out_free:
+	kfree(cps);
+	return NULL;
+}
+
+void nfs4_free_copy_state(struct nfsd4_copy *copy)
+{
+	struct nfsd_net *nn;
+
+	if (copy->cp_stateid.cs_type != NFS4_COPY_STID)
+		return;
+	nn = net_generic(copy->cp_clp->net, nfsd_net_id);
+	spin_lock(&nn->s2s_cp_lock);
+	idr_remove(&nn->s2s_cp_stateids,
+		   copy->cp_stateid.cs_stid.si_opaque.so_id);
+	spin_unlock(&nn->s2s_cp_lock);
+}
+
+static void nfs4_free_cpntf_statelist(struct net *net, struct nfs4_stid *stid)
+{
+	struct nfs4_cpntf_state *cps;
+	struct nfsd_net *nn;
+
+	nn = net_generic(net, nfsd_net_id);
+	spin_lock(&nn->s2s_cp_lock);
+	while (!list_empty(&stid->sc_cp_list)) {
+		cps = list_first_entry(&stid->sc_cp_list,
+				       struct nfs4_cpntf_state, cp_list);
+		_free_cpntf_state_locked(nn, cps);
+	}
+	spin_unlock(&nn->s2s_cp_lock);
+}
+
+static struct nfs4_ol_stateid * nfs4_alloc_open_stateid(struct nfs4_client *clp)
+{
+	struct nfs4_stid *stid;
+
+	stid = nfs4_alloc_stid(clp, stateid_slab, nfs4_free_ol_stateid);
+	if (!stid)
+		return NULL;
+
+	return openlockstateid(stid);
+}
+
+static void nfs4_free_deleg(struct nfs4_stid *stid)
+{
+	struct nfs4_delegation *dp = delegstateid(stid);
+
+	WARN_ON_ONCE(!list_empty(&stid->sc_cp_list));
+	WARN_ON_ONCE(!list_empty(&dp->dl_perfile));
+	WARN_ON_ONCE(!list_empty(&dp->dl_perclnt));
+	WARN_ON_ONCE(!list_empty(&dp->dl_recall_lru));
+	kmem_cache_free(deleg_slab, stid);
+	atomic_long_dec(&num_delegations);
+}
+
+/*
+ * When we recall a delegation, we should be careful not to hand it
+ * out again straight away.
+ * To ensure this we keep a pair of bloom filters ('new' and 'old')
+ * in which the filehandles of recalled delegations are "stored".
+ * If a filehandle appear in either filter, a delegation is blocked.
+ * When a delegation is recalled, the filehandle is stored in the "new"
+ * filter.
+ * Every 30 seconds we swap the filters and clear the "new" one,
+ * unless both are empty of course.
+ *
+ * Each filter is 256 bits.  We hash the filehandle to 32bit and use the
+ * low 3 bytes as hash-table indices.
+ *
+ * 'blocked_delegations_lock', which is always taken in block_delegations(),
+ * is used to manage concurrent access.  Testing does not need the lock
+ * except when swapping the two filters.
+ */
+static DEFINE_SPINLOCK(blocked_delegations_lock);
+static struct bloom_pair {
+	int	entries, old_entries;
+	time64_t swap_time;
+	int	new; /* index into 'set' */
+	DECLARE_BITMAP(set[2], 256);
+} blocked_delegations;
+
+static int delegation_blocked(struct knfsd_fh *fh)
+{
+	u32 hash;
+	struct bloom_pair *bd = &blocked_delegations;
+
+	if (bd->entries == 0)
+		return 0;
+	if (ktime_get_seconds() - bd->swap_time > 30) {
+		spin_lock(&blocked_delegations_lock);
+		if (ktime_get_seconds() - bd->swap_time > 30) {
+			bd->entries -= bd->old_entries;
+			bd->old_entries = bd->entries;
+			memset(bd->set[bd->new], 0,
+			       sizeof(bd->set[0]));
+			bd->new = 1-bd->new;
+			bd->swap_time = ktime_get_seconds();
+		}
+		spin_unlock(&blocked_delegations_lock);
+	}
+	hash = jhash(&fh->fh_raw, fh->fh_size, 0);
+	if (test_bit(hash&255, bd->set[0]) &&
+	    test_bit((hash>>8)&255, bd->set[0]) &&
+	    test_bit((hash>>16)&255, bd->set[0]))
+		return 1;
+
+	if (test_bit(hash&255, bd->set[1]) &&
+	    test_bit((hash>>8)&255, bd->set[1]) &&
+	    test_bit((hash>>16)&255, bd->set[1]))
+		return 1;
+
+	return 0;
+}
+
+static void block_delegations(struct knfsd_fh *fh)
+{
+	u32 hash;
+	struct bloom_pair *bd = &blocked_delegations;
+
+	hash = jhash(&fh->fh_raw, fh->fh_size, 0);
+
+	spin_lock(&blocked_delegations_lock);
+	__set_bit(hash&255, bd->set[bd->new]);
+	__set_bit((hash>>8)&255, bd->set[bd->new]);
+	__set_bit((hash>>16)&255, bd->set[bd->new]);
+	if (bd->entries == 0)
+		bd->swap_time = ktime_get_seconds();
+	bd->entries += 1;
+	spin_unlock(&blocked_delegations_lock);
+}
+
+static struct nfs4_delegation *
+alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
+		 struct nfs4_clnt_odstate *odstate)
+{
+	struct nfs4_delegation *dp;
+	long n;
+
+	dprintk("NFSD alloc_init_deleg\n");
+	n = atomic_long_inc_return(&num_delegations);
+	if (n < 0 || n > max_delegations)
+		goto out_dec;
+	if (delegation_blocked(&fp->fi_fhandle))
+		goto out_dec;
+	dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab, nfs4_free_deleg));
+	if (dp == NULL)
+		goto out_dec;
+
+	/*
+	 * delegation seqid's are never incremented.  The 4.1 special
+	 * meaning of seqid 0 isn't meaningful, really, but let's avoid
+	 * 0 anyway just for consistency and use 1:
+	 */
+	dp->dl_stid.sc_stateid.si_generation = 1;
+	INIT_LIST_HEAD(&dp->dl_perfile);
+	INIT_LIST_HEAD(&dp->dl_perclnt);
+	INIT_LIST_HEAD(&dp->dl_recall_lru);
+	dp->dl_clnt_odstate = odstate;
+	get_clnt_odstate(odstate);
+	dp->dl_type = NFS4_OPEN_DELEGATE_READ;
+	dp->dl_retries = 1;
+	dp->dl_recalled = false;
+	nfsd4_init_cb(&dp->dl_recall, dp->dl_stid.sc_client,
+		      &nfsd4_cb_recall_ops, NFSPROC4_CLNT_CB_RECALL);
+	get_nfs4_file(fp);
+	dp->dl_stid.sc_file = fp;
+	return dp;
+out_dec:
+	atomic_long_dec(&num_delegations);
+	return NULL;
+}
+
+void
+nfs4_put_stid(struct nfs4_stid *s)
+{
+	struct nfs4_file *fp = s->sc_file;
+	struct nfs4_client *clp = s->sc_client;
+
+	might_lock(&clp->cl_lock);
+
+	if (!refcount_dec_and_lock(&s->sc_count, &clp->cl_lock)) {
+		wake_up_all(&close_wq);
+		return;
+	}
+	idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
+	nfs4_free_cpntf_statelist(clp->net, s);
+	spin_unlock(&clp->cl_lock);
+	s->sc_free(s);
+	if (fp)
+		put_nfs4_file(fp);
+}
+
+void
+nfs4_inc_and_copy_stateid(stateid_t *dst, struct nfs4_stid *stid)
+{
+	stateid_t *src = &stid->sc_stateid;
+
+	spin_lock(&stid->sc_lock);
+	if (unlikely(++src->si_generation == 0))
+		src->si_generation = 1;
+	memcpy(dst, src, sizeof(*dst));
+	spin_unlock(&stid->sc_lock);
+}
+
+static void put_deleg_file(struct nfs4_file *fp)
+{
+	struct nfsd_file *nf = NULL;
+
+	spin_lock(&fp->fi_lock);
+	if (--fp->fi_delegees == 0)
+		swap(nf, fp->fi_deleg_file);
+	spin_unlock(&fp->fi_lock);
+
+	if (nf)
+		nfsd_file_put(nf);
+}
+
+static void nfs4_unlock_deleg_lease(struct nfs4_delegation *dp)
+{
+	struct nfs4_file *fp = dp->dl_stid.sc_file;
+	struct nfsd_file *nf = fp->fi_deleg_file;
+
+	WARN_ON_ONCE(!fp->fi_delegees);
+
+	vfs_setlease(nf->nf_file, F_UNLCK, NULL, (void **)&dp);
+	put_deleg_file(fp);
+}
+
+static void destroy_unhashed_deleg(struct nfs4_delegation *dp)
+{
+	put_clnt_odstate(dp->dl_clnt_odstate);
+	nfs4_unlock_deleg_lease(dp);
+	nfs4_put_stid(&dp->dl_stid);
+}
+
+void nfs4_unhash_stid(struct nfs4_stid *s)
+{
+	s->sc_type = 0;
+}
+
+/**
+ * nfs4_delegation_exists - Discover if this delegation already exists
+ * @clp:     a pointer to the nfs4_client we're granting a delegation to
+ * @fp:      a pointer to the nfs4_file we're granting a delegation on
+ *
+ * Return:
+ *      On success: true iff an existing delegation is found
+ */
+
+static bool
+nfs4_delegation_exists(struct nfs4_client *clp, struct nfs4_file *fp)
+{
+	struct nfs4_delegation *searchdp = NULL;
+	struct nfs4_client *searchclp = NULL;
+
+	lockdep_assert_held(&state_lock);
+	lockdep_assert_held(&fp->fi_lock);
+
+	list_for_each_entry(searchdp, &fp->fi_delegations, dl_perfile) {
+		searchclp = searchdp->dl_stid.sc_client;
+		if (clp == searchclp) {
+			return true;
+		}
+	}
+	return false;
+}
+
+/**
+ * hash_delegation_locked - Add a delegation to the appropriate lists
+ * @dp:     a pointer to the nfs4_delegation we are adding.
+ * @fp:     a pointer to the nfs4_file we're granting a delegation on
+ *
+ * Return:
+ *      On success: NULL if the delegation was successfully hashed.
+ *
+ *      On error: -EAGAIN if one was previously granted to this
+ *                 nfs4_client for this nfs4_file. Delegation is not hashed.
+ *
+ */
+
+static int
+hash_delegation_locked(struct nfs4_delegation *dp, struct nfs4_file *fp)
+{
+	struct nfs4_client *clp = dp->dl_stid.sc_client;
+
+	lockdep_assert_held(&state_lock);
+	lockdep_assert_held(&fp->fi_lock);
+
+	if (nfs4_delegation_exists(clp, fp))
+		return -EAGAIN;
+	refcount_inc(&dp->dl_stid.sc_count);
+	dp->dl_stid.sc_type = NFS4_DELEG_STID;
+	list_add(&dp->dl_perfile, &fp->fi_delegations);
+	list_add(&dp->dl_perclnt, &clp->cl_delegations);
+	return 0;
+}
+
+static bool delegation_hashed(struct nfs4_delegation *dp)
+{
+	return !(list_empty(&dp->dl_perfile));
+}
+
+static bool
+unhash_delegation_locked(struct nfs4_delegation *dp)
+{
+	struct nfs4_file *fp = dp->dl_stid.sc_file;
+
+	lockdep_assert_held(&state_lock);
+
+	if (!delegation_hashed(dp))
+		return false;
+
+	dp->dl_stid.sc_type = NFS4_CLOSED_DELEG_STID;
+	/* Ensure that deleg break won't try to requeue it */
+	++dp->dl_time;
+	spin_lock(&fp->fi_lock);
+	list_del_init(&dp->dl_perclnt);
+	list_del_init(&dp->dl_recall_lru);
+	list_del_init(&dp->dl_perfile);
+	spin_unlock(&fp->fi_lock);
+	return true;
+}
+
+static void destroy_delegation(struct nfs4_delegation *dp)
+{
+	bool unhashed;
+
+	spin_lock(&state_lock);
+	unhashed = unhash_delegation_locked(dp);
+	spin_unlock(&state_lock);
+	if (unhashed)
+		destroy_unhashed_deleg(dp);
+}
+
+static void revoke_delegation(struct nfs4_delegation *dp)
+{
+	struct nfs4_client *clp = dp->dl_stid.sc_client;
+
+	WARN_ON(!list_empty(&dp->dl_recall_lru));
+
+	if (clp->cl_minorversion) {
+		spin_lock(&clp->cl_lock);
+		dp->dl_stid.sc_type = NFS4_REVOKED_DELEG_STID;
+		refcount_inc(&dp->dl_stid.sc_count);
+		list_add(&dp->dl_recall_lru, &clp->cl_revoked);
+		spin_unlock(&clp->cl_lock);
+	}
+	destroy_unhashed_deleg(dp);
+}
+
+/* 
+ * SETCLIENTID state 
+ */
+
+static unsigned int clientid_hashval(u32 id)
+{
+	return id & CLIENT_HASH_MASK;
+}
+
+static unsigned int clientstr_hashval(struct xdr_netobj name)
+{
+	return opaque_hashval(name.data, 8) & CLIENT_HASH_MASK;
+}
+
+/*
+ * A stateid that had a deny mode associated with it is being released
+ * or downgraded. Recalculate the deny mode on the file.
+ */
+static void
+recalculate_deny_mode(struct nfs4_file *fp)
+{
+	struct nfs4_ol_stateid *stp;
+
+	spin_lock(&fp->fi_lock);
+	fp->fi_share_deny = 0;
+	list_for_each_entry(stp, &fp->fi_stateids, st_perfile)
+		fp->fi_share_deny |= bmap_to_share_mode(stp->st_deny_bmap);
+	spin_unlock(&fp->fi_lock);
+}
+
+static void
+reset_union_bmap_deny(u32 deny, struct nfs4_ol_stateid *stp)
+{
+	int i;
+	bool change = false;
+
+	for (i = 1; i < 4; i++) {
+		if ((i & deny) != i) {
+			change = true;
+			clear_deny(i, stp);
+		}
+	}
+
+	/* Recalculate per-file deny mode if there was a change */
+	if (change)
+		recalculate_deny_mode(stp->st_stid.sc_file);
+}
+
+/* release all access and file references for a given stateid */
+static void
+release_all_access(struct nfs4_ol_stateid *stp)
+{
+	int i;
+	struct nfs4_file *fp = stp->st_stid.sc_file;
+
+	if (fp && stp->st_deny_bmap != 0)
+		recalculate_deny_mode(fp);
+
+	for (i = 1; i < 4; i++) {
+		if (test_access(i, stp))
+			nfs4_file_put_access(stp->st_stid.sc_file, i);
+		clear_access(i, stp);
+	}
+}
+
+static inline void nfs4_free_stateowner(struct nfs4_stateowner *sop)
+{
+	kfree(sop->so_owner.data);
+	sop->so_ops->so_free(sop);
+}
+
+static void nfs4_put_stateowner(struct nfs4_stateowner *sop)
+{
+	struct nfs4_client *clp = sop->so_client;
+
+	might_lock(&clp->cl_lock);
+
+	if (!atomic_dec_and_lock(&sop->so_count, &clp->cl_lock))
+		return;
+	sop->so_ops->so_unhash(sop);
+	spin_unlock(&clp->cl_lock);
+	nfs4_free_stateowner(sop);
+}
+
+static bool
+nfs4_ol_stateid_unhashed(const struct nfs4_ol_stateid *stp)
+{
+	return list_empty(&stp->st_perfile);
+}
+
+static bool unhash_ol_stateid(struct nfs4_ol_stateid *stp)
+{
+	struct nfs4_file *fp = stp->st_stid.sc_file;
+
+	lockdep_assert_held(&stp->st_stateowner->so_client->cl_lock);
+
+	if (list_empty(&stp->st_perfile))
+		return false;
+
+	spin_lock(&fp->fi_lock);
+	list_del_init(&stp->st_perfile);
+	spin_unlock(&fp->fi_lock);
+	list_del(&stp->st_perstateowner);
+	return true;
+}
+
+static void nfs4_free_ol_stateid(struct nfs4_stid *stid)
+{
+	struct nfs4_ol_stateid *stp = openlockstateid(stid);
+
+	put_clnt_odstate(stp->st_clnt_odstate);
+	release_all_access(stp);
+	if (stp->st_stateowner)
+		nfs4_put_stateowner(stp->st_stateowner);
+	WARN_ON(!list_empty(&stid->sc_cp_list));
+	kmem_cache_free(stateid_slab, stid);
+}
+
+static void nfs4_free_lock_stateid(struct nfs4_stid *stid)
+{
+	struct nfs4_ol_stateid *stp = openlockstateid(stid);
+	struct nfs4_lockowner *lo = lockowner(stp->st_stateowner);
+	struct nfsd_file *nf;
+
+	nf = find_any_file(stp->st_stid.sc_file);
+	if (nf) {
+		get_file(nf->nf_file);
+		filp_close(nf->nf_file, (fl_owner_t)lo);
+		nfsd_file_put(nf);
+	}
+	nfs4_free_ol_stateid(stid);
+}
+
+/*
+ * Put the persistent reference to an already unhashed generic stateid, while
+ * holding the cl_lock. If it's the last reference, then put it onto the
+ * reaplist for later destruction.
+ */
+static void put_ol_stateid_locked(struct nfs4_ol_stateid *stp,
+				       struct list_head *reaplist)
+{
+	struct nfs4_stid *s = &stp->st_stid;
+	struct nfs4_client *clp = s->sc_client;
+
+	lockdep_assert_held(&clp->cl_lock);
+
+	WARN_ON_ONCE(!list_empty(&stp->st_locks));
+
+	if (!refcount_dec_and_test(&s->sc_count)) {
+		wake_up_all(&close_wq);
+		return;
+	}
+
+	idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
+	list_add(&stp->st_locks, reaplist);
+}
+
+static bool unhash_lock_stateid(struct nfs4_ol_stateid *stp)
+{
+	lockdep_assert_held(&stp->st_stid.sc_client->cl_lock);
+
+	if (!unhash_ol_stateid(stp))
+		return false;
+	list_del_init(&stp->st_locks);
+	nfs4_unhash_stid(&stp->st_stid);
+	return true;
+}
+
+static void release_lock_stateid(struct nfs4_ol_stateid *stp)
+{
+	struct nfs4_client *clp = stp->st_stid.sc_client;
+	bool unhashed;
+
+	spin_lock(&clp->cl_lock);
+	unhashed = unhash_lock_stateid(stp);
+	spin_unlock(&clp->cl_lock);
+	if (unhashed)
+		nfs4_put_stid(&stp->st_stid);
+}
+
+static void unhash_lockowner_locked(struct nfs4_lockowner *lo)
+{
+	struct nfs4_client *clp = lo->lo_owner.so_client;
+
+	lockdep_assert_held(&clp->cl_lock);
+
+	list_del_init(&lo->lo_owner.so_strhash);
+}
+
+/*
+ * Free a list of generic stateids that were collected earlier after being
+ * fully unhashed.
+ */
+static void
+free_ol_stateid_reaplist(struct list_head *reaplist)
+{
+	struct nfs4_ol_stateid *stp;
+	struct nfs4_file *fp;
+
+	might_sleep();
+
+	while (!list_empty(reaplist)) {
+		stp = list_first_entry(reaplist, struct nfs4_ol_stateid,
+				       st_locks);
+		list_del(&stp->st_locks);
+		fp = stp->st_stid.sc_file;
+		stp->st_stid.sc_free(&stp->st_stid);
+		if (fp)
+			put_nfs4_file(fp);
+	}
+}
+
+static void release_open_stateid_locks(struct nfs4_ol_stateid *open_stp,
+				       struct list_head *reaplist)
+{
+	struct nfs4_ol_stateid *stp;
+
+	lockdep_assert_held(&open_stp->st_stid.sc_client->cl_lock);
+
+	while (!list_empty(&open_stp->st_locks)) {
+		stp = list_entry(open_stp->st_locks.next,
+				struct nfs4_ol_stateid, st_locks);
+		WARN_ON(!unhash_lock_stateid(stp));
+		put_ol_stateid_locked(stp, reaplist);
+	}
+}
+
+static bool unhash_open_stateid(struct nfs4_ol_stateid *stp,
+				struct list_head *reaplist)
+{
+	lockdep_assert_held(&stp->st_stid.sc_client->cl_lock);
+
+	if (!unhash_ol_stateid(stp))
+		return false;
+	release_open_stateid_locks(stp, reaplist);
+	return true;
+}
+
+static void release_open_stateid(struct nfs4_ol_stateid *stp)
+{
+	LIST_HEAD(reaplist);
+
+	spin_lock(&stp->st_stid.sc_client->cl_lock);
+	if (unhash_open_stateid(stp, &reaplist))
+		put_ol_stateid_locked(stp, &reaplist);
+	spin_unlock(&stp->st_stid.sc_client->cl_lock);
+	free_ol_stateid_reaplist(&reaplist);
+}
+
+static void unhash_openowner_locked(struct nfs4_openowner *oo)
+{
+	struct nfs4_client *clp = oo->oo_owner.so_client;
+
+	lockdep_assert_held(&clp->cl_lock);
+
+	list_del_init(&oo->oo_owner.so_strhash);
+	list_del_init(&oo->oo_perclient);
+}
+
+static void release_last_closed_stateid(struct nfs4_openowner *oo)
+{
+	struct nfsd_net *nn = net_generic(oo->oo_owner.so_client->net,
+					  nfsd_net_id);
+	struct nfs4_ol_stateid *s;
+
+	spin_lock(&nn->client_lock);
+	s = oo->oo_last_closed_stid;
+	if (s) {
+		list_del_init(&oo->oo_close_lru);
+		oo->oo_last_closed_stid = NULL;
+	}
+	spin_unlock(&nn->client_lock);
+	if (s)
+		nfs4_put_stid(&s->st_stid);
+}
+
+static void release_openowner(struct nfs4_openowner *oo)
+{
+	struct nfs4_ol_stateid *stp;
+	struct nfs4_client *clp = oo->oo_owner.so_client;
+	struct list_head reaplist;
+
+	INIT_LIST_HEAD(&reaplist);
+
+	spin_lock(&clp->cl_lock);
+	unhash_openowner_locked(oo);
+	while (!list_empty(&oo->oo_owner.so_stateids)) {
+		stp = list_first_entry(&oo->oo_owner.so_stateids,
+				struct nfs4_ol_stateid, st_perstateowner);
+		if (unhash_open_stateid(stp, &reaplist))
+			put_ol_stateid_locked(stp, &reaplist);
+	}
+	spin_unlock(&clp->cl_lock);
+	free_ol_stateid_reaplist(&reaplist);
+	release_last_closed_stateid(oo);
+	nfs4_put_stateowner(&oo->oo_owner);
+}
+
+static inline int
+hash_sessionid(struct nfs4_sessionid *sessionid)
+{
+	struct nfsd4_sessionid *sid = (struct nfsd4_sessionid *)sessionid;
+
+	return sid->sequence % SESSION_HASH_SIZE;
+}
+
+#ifdef CONFIG_SUNRPC_DEBUG
+static inline void
+dump_sessionid(const char *fn, struct nfs4_sessionid *sessionid)
+{
+	u32 *ptr = (u32 *)(&sessionid->data[0]);
+	dprintk("%s: %u:%u:%u:%u\n", fn, ptr[0], ptr[1], ptr[2], ptr[3]);
+}
+#else
+static inline void
+dump_sessionid(const char *fn, struct nfs4_sessionid *sessionid)
+{
+}
+#endif
+
+/*
+ * Bump the seqid on cstate->replay_owner, and clear replay_owner if it
+ * won't be used for replay.
+ */
+void nfsd4_bump_seqid(struct nfsd4_compound_state *cstate, __be32 nfserr)
+{
+	struct nfs4_stateowner *so = cstate->replay_owner;
+
+	if (nfserr == nfserr_replay_me)
+		return;
+
+	if (!seqid_mutating_err(ntohl(nfserr))) {
+		nfsd4_cstate_clear_replay(cstate);
+		return;
+	}
+	if (!so)
+		return;
+	if (so->so_is_open_owner)
+		release_last_closed_stateid(openowner(so));
+	so->so_seqid++;
+	return;
+}
+
+static void
+gen_sessionid(struct nfsd4_session *ses)
+{
+	struct nfs4_client *clp = ses->se_client;
+	struct nfsd4_sessionid *sid;
+
+	sid = (struct nfsd4_sessionid *)ses->se_sessionid.data;
+	sid->clientid = clp->cl_clientid;
+	sid->sequence = current_sessionid++;
+	sid->reserved = 0;
+}
+
+/*
+ * The protocol defines ca_maxresponssize_cached to include the size of
+ * the rpc header, but all we need to cache is the data starting after
+ * the end of the initial SEQUENCE operation--the rest we regenerate
+ * each time.  Therefore we can advertise a ca_maxresponssize_cached
+ * value that is the number of bytes in our cache plus a few additional
+ * bytes.  In order to stay on the safe side, and not promise more than
+ * we can cache, those additional bytes must be the minimum possible: 24
+ * bytes of rpc header (xid through accept state, with AUTH_NULL
+ * verifier), 12 for the compound header (with zero-length tag), and 44
+ * for the SEQUENCE op response:
+ */
+#define NFSD_MIN_HDR_SEQ_SZ  (24 + 12 + 44)
+
+static void
+free_session_slots(struct nfsd4_session *ses)
+{
+	int i;
+
+	for (i = 0; i < ses->se_fchannel.maxreqs; i++) {
+		free_svc_cred(&ses->se_slots[i]->sl_cred);
+		kfree(ses->se_slots[i]);
+	}
+}
+
+/*
+ * We don't actually need to cache the rpc and session headers, so we
+ * can allocate a little less for each slot:
+ */
+static inline u32 slot_bytes(struct nfsd4_channel_attrs *ca)
+{
+	u32 size;
+
+	if (ca->maxresp_cached < NFSD_MIN_HDR_SEQ_SZ)
+		size = 0;
+	else
+		size = ca->maxresp_cached - NFSD_MIN_HDR_SEQ_SZ;
+	return size + sizeof(struct nfsd4_slot);
+}
+
+/*
+ * XXX: If we run out of reserved DRC memory we could (up to a point)
+ * re-negotiate active sessions and reduce their slot usage to make
+ * room for new connections. For now we just fail the create session.
+ */
+static u32 nfsd4_get_drc_mem(struct nfsd4_channel_attrs *ca, struct nfsd_net *nn)
+{
+	u32 slotsize = slot_bytes(ca);
+	u32 num = ca->maxreqs;
+	unsigned long avail, total_avail;
+	unsigned int scale_factor;
+
+	spin_lock(&nfsd_drc_lock);
+	if (nfsd_drc_max_mem > nfsd_drc_mem_used)
+		total_avail = nfsd_drc_max_mem - nfsd_drc_mem_used;
+	else
+		/* We have handed out more space than we chose in
+		 * set_max_drc() to allow.  That isn't really a
+		 * problem as long as that doesn't make us think we
+		 * have lots more due to integer overflow.
+		 */
+		total_avail = 0;
+	avail = min((unsigned long)NFSD_MAX_MEM_PER_SESSION, total_avail);
+	/*
+	 * Never use more than a fraction of the remaining memory,
+	 * unless it's the only way to give this client a slot.
+	 * The chosen fraction is either 1/8 or 1/number of threads,
+	 * whichever is smaller.  This ensures there are adequate
+	 * slots to support multiple clients per thread.
+	 * Give the client one slot even if that would require
+	 * over-allocation--it is better than failure.
+	 */
+	scale_factor = max_t(unsigned int, 8, nn->nfsd_serv->sv_nrthreads);
+
+	avail = clamp_t(unsigned long, avail, slotsize,
+			total_avail/scale_factor);
+	num = min_t(int, num, avail / slotsize);
+	num = max_t(int, num, 1);
+	nfsd_drc_mem_used += num * slotsize;
+	spin_unlock(&nfsd_drc_lock);
+
+	return num;
+}
+
+static void nfsd4_put_drc_mem(struct nfsd4_channel_attrs *ca)
+{
+	int slotsize = slot_bytes(ca);
+
+	spin_lock(&nfsd_drc_lock);
+	nfsd_drc_mem_used -= slotsize * ca->maxreqs;
+	spin_unlock(&nfsd_drc_lock);
+}
+
+static struct nfsd4_session *alloc_session(struct nfsd4_channel_attrs *fattrs,
+					   struct nfsd4_channel_attrs *battrs)
+{
+	int numslots = fattrs->maxreqs;
+	int slotsize = slot_bytes(fattrs);
+	struct nfsd4_session *new;
+	int mem, i;
+
+	BUILD_BUG_ON(NFSD_MAX_SLOTS_PER_SESSION * sizeof(struct nfsd4_slot *)
+			+ sizeof(struct nfsd4_session) > PAGE_SIZE);
+	mem = numslots * sizeof(struct nfsd4_slot *);
+
+	new = kzalloc(sizeof(*new) + mem, GFP_KERNEL);
+	if (!new)
+		return NULL;
+	/* allocate each struct nfsd4_slot and data cache in one piece */
+	for (i = 0; i < numslots; i++) {
+		new->se_slots[i] = kzalloc(slotsize, GFP_KERNEL);
+		if (!new->se_slots[i])
+			goto out_free;
+	}
+
+	memcpy(&new->se_fchannel, fattrs, sizeof(struct nfsd4_channel_attrs));
+	memcpy(&new->se_bchannel, battrs, sizeof(struct nfsd4_channel_attrs));
+
+	return new;
+out_free:
+	while (i--)
+		kfree(new->se_slots[i]);
+	kfree(new);
+	return NULL;
+}
+
+static void free_conn(struct nfsd4_conn *c)
+{
+	svc_xprt_put(c->cn_xprt);
+	kfree(c);
+}
+
+static void nfsd4_conn_lost(struct svc_xpt_user *u)
+{
+	struct nfsd4_conn *c = container_of(u, struct nfsd4_conn, cn_xpt_user);
+	struct nfs4_client *clp = c->cn_session->se_client;
+
+	trace_nfsd_cb_lost(clp);
+
+	spin_lock(&clp->cl_lock);
+	if (!list_empty(&c->cn_persession)) {
+		list_del(&c->cn_persession);
+		free_conn(c);
+	}
+	nfsd4_probe_callback(clp);
+	spin_unlock(&clp->cl_lock);
+}
+
+static struct nfsd4_conn *alloc_conn(struct svc_rqst *rqstp, u32 flags)
+{
+	struct nfsd4_conn *conn;
+
+	conn = kmalloc(sizeof(struct nfsd4_conn), GFP_KERNEL);
+	if (!conn)
+		return NULL;
+	svc_xprt_get(rqstp->rq_xprt);
+	conn->cn_xprt = rqstp->rq_xprt;
+	conn->cn_flags = flags;
+	INIT_LIST_HEAD(&conn->cn_xpt_user.list);
+	return conn;
+}
+
+static void __nfsd4_hash_conn(struct nfsd4_conn *conn, struct nfsd4_session *ses)
+{
+	conn->cn_session = ses;
+	list_add(&conn->cn_persession, &ses->se_conns);
+}
+
+static void nfsd4_hash_conn(struct nfsd4_conn *conn, struct nfsd4_session *ses)
+{
+	struct nfs4_client *clp = ses->se_client;
+
+	spin_lock(&clp->cl_lock);
+	__nfsd4_hash_conn(conn, ses);
+	spin_unlock(&clp->cl_lock);
+}
+
+static int nfsd4_register_conn(struct nfsd4_conn *conn)
+{
+	conn->cn_xpt_user.callback = nfsd4_conn_lost;
+	return register_xpt_user(conn->cn_xprt, &conn->cn_xpt_user);
+}
+
+static void nfsd4_init_conn(struct svc_rqst *rqstp, struct nfsd4_conn *conn, struct nfsd4_session *ses)
+{
+	int ret;
+
+	nfsd4_hash_conn(conn, ses);
+	ret = nfsd4_register_conn(conn);
+	if (ret)
+		/* oops; xprt is already down: */
+		nfsd4_conn_lost(&conn->cn_xpt_user);
+	/* We may have gained or lost a callback channel: */
+	nfsd4_probe_callback_sync(ses->se_client);
+}
+
+static struct nfsd4_conn *alloc_conn_from_crses(struct svc_rqst *rqstp, struct nfsd4_create_session *cses)
+{
+	u32 dir = NFS4_CDFC4_FORE;
+
+	if (cses->flags & SESSION4_BACK_CHAN)
+		dir |= NFS4_CDFC4_BACK;
+	return alloc_conn(rqstp, dir);
+}
+
+/* must be called under client_lock */
+static void nfsd4_del_conns(struct nfsd4_session *s)
+{
+	struct nfs4_client *clp = s->se_client;
+	struct nfsd4_conn *c;
+
+	spin_lock(&clp->cl_lock);
+	while (!list_empty(&s->se_conns)) {
+		c = list_first_entry(&s->se_conns, struct nfsd4_conn, cn_persession);
+		list_del_init(&c->cn_persession);
+		spin_unlock(&clp->cl_lock);
+
+		unregister_xpt_user(c->cn_xprt, &c->cn_xpt_user);
+		free_conn(c);
+
+		spin_lock(&clp->cl_lock);
+	}
+	spin_unlock(&clp->cl_lock);
+}
+
+static void __free_session(struct nfsd4_session *ses)
+{
+	free_session_slots(ses);
+	kfree(ses);
+}
+
+static void free_session(struct nfsd4_session *ses)
+{
+	nfsd4_del_conns(ses);
+	nfsd4_put_drc_mem(&ses->se_fchannel);
+	__free_session(ses);
+}
+
+static void init_session(struct svc_rqst *rqstp, struct nfsd4_session *new, struct nfs4_client *clp, struct nfsd4_create_session *cses)
+{
+	int idx;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	new->se_client = clp;
+	gen_sessionid(new);
+
+	INIT_LIST_HEAD(&new->se_conns);
+
+	new->se_cb_seq_nr = 1;
+	new->se_flags = cses->flags;
+	new->se_cb_prog = cses->callback_prog;
+	new->se_cb_sec = cses->cb_sec;
+	atomic_set(&new->se_ref, 0);
+	idx = hash_sessionid(&new->se_sessionid);
+	list_add(&new->se_hash, &nn->sessionid_hashtbl[idx]);
+	spin_lock(&clp->cl_lock);
+	list_add(&new->se_perclnt, &clp->cl_sessions);
+	spin_unlock(&clp->cl_lock);
+
+	{
+		struct sockaddr *sa = svc_addr(rqstp);
+		/*
+		 * This is a little silly; with sessions there's no real
+		 * use for the callback address.  Use the peer address
+		 * as a reasonable default for now, but consider fixing
+		 * the rpc client not to require an address in the
+		 * future:
+		 */
+		rpc_copy_addr((struct sockaddr *)&clp->cl_cb_conn.cb_addr, sa);
+		clp->cl_cb_conn.cb_addrlen = svc_addr_len(sa);
+	}
+}
+
+/* caller must hold client_lock */
+static struct nfsd4_session *
+__find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
+{
+	struct nfsd4_session *elem;
+	int idx;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	lockdep_assert_held(&nn->client_lock);
+
+	dump_sessionid(__func__, sessionid);
+	idx = hash_sessionid(sessionid);
+	/* Search in the appropriate list */
+	list_for_each_entry(elem, &nn->sessionid_hashtbl[idx], se_hash) {
+		if (!memcmp(elem->se_sessionid.data, sessionid->data,
+			    NFS4_MAX_SESSIONID_LEN)) {
+			return elem;
+		}
+	}
+
+	dprintk("%s: session not found\n", __func__);
+	return NULL;
+}
+
+static struct nfsd4_session *
+find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
+		__be32 *ret)
+{
+	struct nfsd4_session *session;
+	__be32 status = nfserr_badsession;
+
+	session = __find_in_sessionid_hashtbl(sessionid, net);
+	if (!session)
+		goto out;
+	status = nfsd4_get_session_locked(session);
+	if (status)
+		session = NULL;
+out:
+	*ret = status;
+	return session;
+}
+
+/* caller must hold client_lock */
+static void
+unhash_session(struct nfsd4_session *ses)
+{
+	struct nfs4_client *clp = ses->se_client;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	lockdep_assert_held(&nn->client_lock);
+
+	list_del(&ses->se_hash);
+	spin_lock(&ses->se_client->cl_lock);
+	list_del(&ses->se_perclnt);
+	spin_unlock(&ses->se_client->cl_lock);
+}
+
+/* SETCLIENTID and SETCLIENTID_CONFIRM Helper functions */
+static int
+STALE_CLIENTID(clientid_t *clid, struct nfsd_net *nn)
+{
+	/*
+	 * We're assuming the clid was not given out from a boot
+	 * precisely 2^32 (about 136 years) before this one.  That seems
+	 * a safe assumption:
+	 */
+	if (clid->cl_boot == (u32)nn->boot_time)
+		return 0;
+	trace_nfsd_clid_stale(clid);
+	return 1;
+}
+
+/* 
+ * XXX Should we use a slab cache ?
+ * This type of memory management is somewhat inefficient, but we use it
+ * anyway since SETCLIENTID is not a common operation.
+ */
+static struct nfs4_client *alloc_client(struct xdr_netobj name,
+				struct nfsd_net *nn)
+{
+	struct nfs4_client *clp;
+	int i;
+
+	if (atomic_read(&nn->nfs4_client_count) >= nn->nfs4_max_clients) {
+		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+		return NULL;
+	}
+	clp = kmem_cache_zalloc(client_slab, GFP_KERNEL);
+	if (clp == NULL)
+		return NULL;
+	xdr_netobj_dup(&clp->cl_name, &name, GFP_KERNEL);
+	if (clp->cl_name.data == NULL)
+		goto err_no_name;
+	clp->cl_ownerstr_hashtbl = kmalloc_array(OWNER_HASH_SIZE,
+						 sizeof(struct list_head),
+						 GFP_KERNEL);
+	if (!clp->cl_ownerstr_hashtbl)
+		goto err_no_hashtbl;
+	for (i = 0; i < OWNER_HASH_SIZE; i++)
+		INIT_LIST_HEAD(&clp->cl_ownerstr_hashtbl[i]);
+	INIT_LIST_HEAD(&clp->cl_sessions);
+	idr_init(&clp->cl_stateids);
+	atomic_set(&clp->cl_rpc_users, 0);
+	clp->cl_cb_state = NFSD4_CB_UNKNOWN;
+	clp->cl_state = NFSD4_ACTIVE;
+	atomic_inc(&nn->nfs4_client_count);
+	atomic_set(&clp->cl_delegs_in_recall, 0);
+	INIT_LIST_HEAD(&clp->cl_idhash);
+	INIT_LIST_HEAD(&clp->cl_openowners);
+	INIT_LIST_HEAD(&clp->cl_delegations);
+	INIT_LIST_HEAD(&clp->cl_lru);
+	INIT_LIST_HEAD(&clp->cl_revoked);
+#ifdef CONFIG_NFSD_PNFS
+	INIT_LIST_HEAD(&clp->cl_lo_states);
+#endif
+	INIT_LIST_HEAD(&clp->async_copies);
+	spin_lock_init(&clp->async_lock);
+	spin_lock_init(&clp->cl_lock);
+	rpc_init_wait_queue(&clp->cl_cb_waitq, "Backchannel slot table");
+	return clp;
+err_no_hashtbl:
+	kfree(clp->cl_name.data);
+err_no_name:
+	kmem_cache_free(client_slab, clp);
+	return NULL;
+}
+
+static void __free_client(struct kref *k)
+{
+	struct nfsdfs_client *c = container_of(k, struct nfsdfs_client, cl_ref);
+	struct nfs4_client *clp = container_of(c, struct nfs4_client, cl_nfsdfs);
+
+	free_svc_cred(&clp->cl_cred);
+	kfree(clp->cl_ownerstr_hashtbl);
+	kfree(clp->cl_name.data);
+	kfree(clp->cl_nii_domain.data);
+	kfree(clp->cl_nii_name.data);
+	idr_destroy(&clp->cl_stateids);
+	kmem_cache_free(client_slab, clp);
+}
+
+static void drop_client(struct nfs4_client *clp)
+{
+	kref_put(&clp->cl_nfsdfs.cl_ref, __free_client);
+}
+
+static void
+free_client(struct nfs4_client *clp)
+{
+	while (!list_empty(&clp->cl_sessions)) {
+		struct nfsd4_session *ses;
+		ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,
+				se_perclnt);
+		list_del(&ses->se_perclnt);
+		WARN_ON_ONCE(atomic_read(&ses->se_ref));
+		free_session(ses);
+	}
+	rpc_destroy_wait_queue(&clp->cl_cb_waitq);
+	if (clp->cl_nfsd_dentry) {
+		nfsd_client_rmdir(clp->cl_nfsd_dentry);
+		clp->cl_nfsd_dentry = NULL;
+		wake_up_all(&expiry_wq);
+	}
+	drop_client(clp);
+}
+
+/* must be called under the client_lock */
+static void
+unhash_client_locked(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct nfsd4_session *ses;
+
+	lockdep_assert_held(&nn->client_lock);
+
+	/* Mark the client as expired! */
+	clp->cl_time = 0;
+	/* Make it invisible */
+	if (!list_empty(&clp->cl_idhash)) {
+		list_del_init(&clp->cl_idhash);
+		if (test_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags))
+			rb_erase(&clp->cl_namenode, &nn->conf_name_tree);
+		else
+			rb_erase(&clp->cl_namenode, &nn->unconf_name_tree);
+	}
+	list_del_init(&clp->cl_lru);
+	spin_lock(&clp->cl_lock);
+	list_for_each_entry(ses, &clp->cl_sessions, se_perclnt)
+		list_del_init(&ses->se_hash);
+	spin_unlock(&clp->cl_lock);
+}
+
+static void
+unhash_client(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	spin_lock(&nn->client_lock);
+	unhash_client_locked(clp);
+	spin_unlock(&nn->client_lock);
+}
+
+static __be32 mark_client_expired_locked(struct nfs4_client *clp)
+{
+	if (atomic_read(&clp->cl_rpc_users))
+		return nfserr_jukebox;
+	unhash_client_locked(clp);
+	return nfs_ok;
+}
+
+static void
+__destroy_client(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	int i;
+	struct nfs4_openowner *oo;
+	struct nfs4_delegation *dp;
+	struct list_head reaplist;
+
+	INIT_LIST_HEAD(&reaplist);
+	spin_lock(&state_lock);
+	while (!list_empty(&clp->cl_delegations)) {
+		dp = list_entry(clp->cl_delegations.next, struct nfs4_delegation, dl_perclnt);
+		WARN_ON(!unhash_delegation_locked(dp));
+		list_add(&dp->dl_recall_lru, &reaplist);
+	}
+	spin_unlock(&state_lock);
+	while (!list_empty(&reaplist)) {
+		dp = list_entry(reaplist.next, struct nfs4_delegation, dl_recall_lru);
+		list_del_init(&dp->dl_recall_lru);
+		destroy_unhashed_deleg(dp);
+	}
+	while (!list_empty(&clp->cl_revoked)) {
+		dp = list_entry(clp->cl_revoked.next, struct nfs4_delegation, dl_recall_lru);
+		list_del_init(&dp->dl_recall_lru);
+		nfs4_put_stid(&dp->dl_stid);
+	}
+	while (!list_empty(&clp->cl_openowners)) {
+		oo = list_entry(clp->cl_openowners.next, struct nfs4_openowner, oo_perclient);
+		nfs4_get_stateowner(&oo->oo_owner);
+		release_openowner(oo);
+	}
+	for (i = 0; i < OWNER_HASH_SIZE; i++) {
+		struct nfs4_stateowner *so, *tmp;
+
+		list_for_each_entry_safe(so, tmp, &clp->cl_ownerstr_hashtbl[i],
+					 so_strhash) {
+			/* Should be no openowners at this point */
+			WARN_ON_ONCE(so->so_is_open_owner);
+			remove_blocked_locks(lockowner(so));
+		}
+	}
+	nfsd4_return_all_client_layouts(clp);
+	nfsd4_shutdown_copy(clp);
+	nfsd4_shutdown_callback(clp);
+	if (clp->cl_cb_conn.cb_xprt)
+		svc_xprt_put(clp->cl_cb_conn.cb_xprt);
+	atomic_add_unless(&nn->nfs4_client_count, -1, 0);
+	nfsd4_dec_courtesy_client_count(nn, clp);
+	free_client(clp);
+	wake_up_all(&expiry_wq);
+}
+
+static void
+destroy_client(struct nfs4_client *clp)
+{
+	unhash_client(clp);
+	__destroy_client(clp);
+}
+
+static void inc_reclaim_complete(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	if (!nn->track_reclaim_completes)
+		return;
+	if (!nfsd4_find_reclaim_client(clp->cl_name, nn))
+		return;
+	if (atomic_inc_return(&nn->nr_reclaim_complete) ==
+			nn->reclaim_str_hashtbl_size) {
+		printk(KERN_INFO "NFSD: all clients done reclaiming, ending NFSv4 grace period (net %x)\n",
+				clp->net->ns.inum);
+		nfsd4_end_grace(nn);
+	}
+}
+
+static void expire_client(struct nfs4_client *clp)
+{
+	unhash_client(clp);
+	nfsd4_client_record_remove(clp);
+	__destroy_client(clp);
+}
+
+static void copy_verf(struct nfs4_client *target, nfs4_verifier *source)
+{
+	memcpy(target->cl_verifier.data, source->data,
+			sizeof(target->cl_verifier.data));
+}
+
+static void copy_clid(struct nfs4_client *target, struct nfs4_client *source)
+{
+	target->cl_clientid.cl_boot = source->cl_clientid.cl_boot; 
+	target->cl_clientid.cl_id = source->cl_clientid.cl_id; 
+}
+
+static int copy_cred(struct svc_cred *target, struct svc_cred *source)
+{
+	target->cr_principal = kstrdup(source->cr_principal, GFP_KERNEL);
+	target->cr_raw_principal = kstrdup(source->cr_raw_principal,
+								GFP_KERNEL);
+	target->cr_targ_princ = kstrdup(source->cr_targ_princ, GFP_KERNEL);
+	if ((source->cr_principal && !target->cr_principal) ||
+	    (source->cr_raw_principal && !target->cr_raw_principal) ||
+	    (source->cr_targ_princ && !target->cr_targ_princ))
+		return -ENOMEM;
+
+	target->cr_flavor = source->cr_flavor;
+	target->cr_uid = source->cr_uid;
+	target->cr_gid = source->cr_gid;
+	target->cr_group_info = source->cr_group_info;
+	get_group_info(target->cr_group_info);
+	target->cr_gss_mech = source->cr_gss_mech;
+	if (source->cr_gss_mech)
+		gss_mech_get(source->cr_gss_mech);
+	return 0;
+}
+
+static int
+compare_blob(const struct xdr_netobj *o1, const struct xdr_netobj *o2)
+{
+	if (o1->len < o2->len)
+		return -1;
+	if (o1->len > o2->len)
+		return 1;
+	return memcmp(o1->data, o2->data, o1->len);
+}
+
+static int
+same_verf(nfs4_verifier *v1, nfs4_verifier *v2)
+{
+	return 0 == memcmp(v1->data, v2->data, sizeof(v1->data));
+}
+
+static int
+same_clid(clientid_t *cl1, clientid_t *cl2)
+{
+	return (cl1->cl_boot == cl2->cl_boot) && (cl1->cl_id == cl2->cl_id);
+}
+
+static bool groups_equal(struct group_info *g1, struct group_info *g2)
+{
+	int i;
+
+	if (g1->ngroups != g2->ngroups)
+		return false;
+	for (i=0; i<g1->ngroups; i++)
+		if (!gid_eq(g1->gid[i], g2->gid[i]))
+			return false;
+	return true;
+}
+
+/*
+ * RFC 3530 language requires clid_inuse be returned when the
+ * "principal" associated with a requests differs from that previously
+ * used.  We use uid, gid's, and gss principal string as our best
+ * approximation.  We also don't want to allow non-gss use of a client
+ * established using gss: in theory cr_principal should catch that
+ * change, but in practice cr_principal can be null even in the gss case
+ * since gssd doesn't always pass down a principal string.
+ */
+static bool is_gss_cred(struct svc_cred *cr)
+{
+	/* Is cr_flavor one of the gss "pseudoflavors"?: */
+	return (cr->cr_flavor > RPC_AUTH_MAXFLAVOR);
+}
+
+
+static bool
+same_creds(struct svc_cred *cr1, struct svc_cred *cr2)
+{
+	if ((is_gss_cred(cr1) != is_gss_cred(cr2))
+		|| (!uid_eq(cr1->cr_uid, cr2->cr_uid))
+		|| (!gid_eq(cr1->cr_gid, cr2->cr_gid))
+		|| !groups_equal(cr1->cr_group_info, cr2->cr_group_info))
+		return false;
+	/* XXX: check that cr_targ_princ fields match ? */
+	if (cr1->cr_principal == cr2->cr_principal)
+		return true;
+	if (!cr1->cr_principal || !cr2->cr_principal)
+		return false;
+	return 0 == strcmp(cr1->cr_principal, cr2->cr_principal);
+}
+
+static bool svc_rqst_integrity_protected(struct svc_rqst *rqstp)
+{
+	struct svc_cred *cr = &rqstp->rq_cred;
+	u32 service;
+
+	if (!cr->cr_gss_mech)
+		return false;
+	service = gss_pseudoflavor_to_service(cr->cr_gss_mech, cr->cr_flavor);
+	return service == RPC_GSS_SVC_INTEGRITY ||
+	       service == RPC_GSS_SVC_PRIVACY;
+}
+
+bool nfsd4_mach_creds_match(struct nfs4_client *cl, struct svc_rqst *rqstp)
+{
+	struct svc_cred *cr = &rqstp->rq_cred;
+
+	if (!cl->cl_mach_cred)
+		return true;
+	if (cl->cl_cred.cr_gss_mech != cr->cr_gss_mech)
+		return false;
+	if (!svc_rqst_integrity_protected(rqstp))
+		return false;
+	if (cl->cl_cred.cr_raw_principal)
+		return 0 == strcmp(cl->cl_cred.cr_raw_principal,
+						cr->cr_raw_principal);
+	if (!cr->cr_principal)
+		return false;
+	return 0 == strcmp(cl->cl_cred.cr_principal, cr->cr_principal);
+}
+
+static void gen_confirm(struct nfs4_client *clp, struct nfsd_net *nn)
+{
+	__be32 verf[2];
+
+	/*
+	 * This is opaque to client, so no need to byte-swap. Use
+	 * __force to keep sparse happy
+	 */
+	verf[0] = (__force __be32)(u32)ktime_get_real_seconds();
+	verf[1] = (__force __be32)nn->clverifier_counter++;
+	memcpy(clp->cl_confirm.data, verf, sizeof(clp->cl_confirm.data));
+}
+
+static void gen_clid(struct nfs4_client *clp, struct nfsd_net *nn)
+{
+	clp->cl_clientid.cl_boot = (u32)nn->boot_time;
+	clp->cl_clientid.cl_id = nn->clientid_counter++;
+	gen_confirm(clp, nn);
+}
+
+static struct nfs4_stid *
+find_stateid_locked(struct nfs4_client *cl, stateid_t *t)
+{
+	struct nfs4_stid *ret;
+
+	ret = idr_find(&cl->cl_stateids, t->si_opaque.so_id);
+	if (!ret || !ret->sc_type)
+		return NULL;
+	return ret;
+}
+
+static struct nfs4_stid *
+find_stateid_by_type(struct nfs4_client *cl, stateid_t *t, char typemask)
+{
+	struct nfs4_stid *s;
+
+	spin_lock(&cl->cl_lock);
+	s = find_stateid_locked(cl, t);
+	if (s != NULL) {
+		if (typemask & s->sc_type)
+			refcount_inc(&s->sc_count);
+		else
+			s = NULL;
+	}
+	spin_unlock(&cl->cl_lock);
+	return s;
+}
+
+static struct nfs4_client *get_nfsdfs_clp(struct inode *inode)
+{
+	struct nfsdfs_client *nc;
+	nc = get_nfsdfs_client(inode);
+	if (!nc)
+		return NULL;
+	return container_of(nc, struct nfs4_client, cl_nfsdfs);
+}
+
+static void seq_quote_mem(struct seq_file *m, char *data, int len)
+{
+	seq_printf(m, "\"");
+	seq_escape_mem(m, data, len, ESCAPE_HEX | ESCAPE_NAP | ESCAPE_APPEND, "\"\\");
+	seq_printf(m, "\"");
+}
+
+static const char *cb_state2str(int state)
+{
+	switch (state) {
+	case NFSD4_CB_UP:
+		return "UP";
+	case NFSD4_CB_UNKNOWN:
+		return "UNKNOWN";
+	case NFSD4_CB_DOWN:
+		return "DOWN";
+	case NFSD4_CB_FAULT:
+		return "FAULT";
+	}
+	return "UNDEFINED";
+}
+
+static int client_info_show(struct seq_file *m, void *v)
+{
+	struct inode *inode = file_inode(m->file);
+	struct nfs4_client *clp;
+	u64 clid;
+
+	clp = get_nfsdfs_clp(inode);
+	if (!clp)
+		return -ENXIO;
+	memcpy(&clid, &clp->cl_clientid, sizeof(clid));
+	seq_printf(m, "clientid: 0x%llx\n", clid);
+	seq_printf(m, "address: \"%pISpc\"\n", (struct sockaddr *)&clp->cl_addr);
+
+	if (clp->cl_state == NFSD4_COURTESY)
+		seq_puts(m, "status: courtesy\n");
+	else if (clp->cl_state == NFSD4_EXPIRABLE)
+		seq_puts(m, "status: expirable\n");
+	else if (test_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags))
+		seq_puts(m, "status: confirmed\n");
+	else
+		seq_puts(m, "status: unconfirmed\n");
+	seq_printf(m, "seconds from last renew: %lld\n",
+		ktime_get_boottime_seconds() - clp->cl_time);
+	seq_printf(m, "name: ");
+	seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
+	seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
+	if (clp->cl_nii_domain.data) {
+		seq_printf(m, "Implementation domain: ");
+		seq_quote_mem(m, clp->cl_nii_domain.data,
+					clp->cl_nii_domain.len);
+		seq_printf(m, "\nImplementation name: ");
+		seq_quote_mem(m, clp->cl_nii_name.data, clp->cl_nii_name.len);
+		seq_printf(m, "\nImplementation time: [%lld, %ld]\n",
+			clp->cl_nii_time.tv_sec, clp->cl_nii_time.tv_nsec);
+	}
+	seq_printf(m, "callback state: %s\n", cb_state2str(clp->cl_cb_state));
+	seq_printf(m, "callback address: %pISpc\n", &clp->cl_cb_conn.cb_addr);
+	drop_client(clp);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(client_info);
+
+static void *states_start(struct seq_file *s, loff_t *pos)
+	__acquires(&clp->cl_lock)
+{
+	struct nfs4_client *clp = s->private;
+	unsigned long id = *pos;
+	void *ret;
+
+	spin_lock(&clp->cl_lock);
+	ret = idr_get_next_ul(&clp->cl_stateids, &id);
+	*pos = id;
+	return ret;
+}
+
+static void *states_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	struct nfs4_client *clp = s->private;
+	unsigned long id = *pos;
+	void *ret;
+
+	id = *pos;
+	id++;
+	ret = idr_get_next_ul(&clp->cl_stateids, &id);
+	*pos = id;
+	return ret;
+}
+
+static void states_stop(struct seq_file *s, void *v)
+	__releases(&clp->cl_lock)
+{
+	struct nfs4_client *clp = s->private;
+
+	spin_unlock(&clp->cl_lock);
+}
+
+static void nfs4_show_fname(struct seq_file *s, struct nfsd_file *f)
+{
+         seq_printf(s, "filename: \"%pD2\"", f->nf_file);
+}
+
+static void nfs4_show_superblock(struct seq_file *s, struct nfsd_file *f)
+{
+	struct inode *inode = file_inode(f->nf_file);
+
+	seq_printf(s, "superblock: \"%02x:%02x:%ld\"",
+					MAJOR(inode->i_sb->s_dev),
+					 MINOR(inode->i_sb->s_dev),
+					 inode->i_ino);
+}
+
+static void nfs4_show_owner(struct seq_file *s, struct nfs4_stateowner *oo)
+{
+	seq_printf(s, "owner: ");
+	seq_quote_mem(s, oo->so_owner.data, oo->so_owner.len);
+}
+
+static void nfs4_show_stateid(struct seq_file *s, stateid_t *stid)
+{
+	seq_printf(s, "0x%.8x", stid->si_generation);
+	seq_printf(s, "%12phN", &stid->si_opaque);
+}
+
+static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st)
+{
+	struct nfs4_ol_stateid *ols;
+	struct nfs4_file *nf;
+	struct nfsd_file *file;
+	struct nfs4_stateowner *oo;
+	unsigned int access, deny;
+
+	if (st->sc_type != NFS4_OPEN_STID && st->sc_type != NFS4_LOCK_STID)
+		return 0; /* XXX: or SEQ_SKIP? */
+	ols = openlockstateid(st);
+	oo = ols->st_stateowner;
+	nf = st->sc_file;
+
+	spin_lock(&nf->fi_lock);
+	file = find_any_file_locked(nf);
+	if (!file)
+		goto out;
+
+	seq_printf(s, "- ");
+	nfs4_show_stateid(s, &st->sc_stateid);
+	seq_printf(s, ": { type: open, ");
+
+	access = bmap_to_share_mode(ols->st_access_bmap);
+	deny   = bmap_to_share_mode(ols->st_deny_bmap);
+
+	seq_printf(s, "access: %s%s, ",
+		access & NFS4_SHARE_ACCESS_READ ? "r" : "-",
+		access & NFS4_SHARE_ACCESS_WRITE ? "w" : "-");
+	seq_printf(s, "deny: %s%s, ",
+		deny & NFS4_SHARE_ACCESS_READ ? "r" : "-",
+		deny & NFS4_SHARE_ACCESS_WRITE ? "w" : "-");
+
+	nfs4_show_superblock(s, file);
+	seq_printf(s, ", ");
+	nfs4_show_fname(s, file);
+	seq_printf(s, ", ");
+	nfs4_show_owner(s, oo);
+	seq_printf(s, " }\n");
+out:
+	spin_unlock(&nf->fi_lock);
+	return 0;
+}
+
+static int nfs4_show_lock(struct seq_file *s, struct nfs4_stid *st)
+{
+	struct nfs4_ol_stateid *ols;
+	struct nfs4_file *nf;
+	struct nfsd_file *file;
+	struct nfs4_stateowner *oo;
+
+	ols = openlockstateid(st);
+	oo = ols->st_stateowner;
+	nf = st->sc_file;
+	spin_lock(&nf->fi_lock);
+	file = find_any_file_locked(nf);
+	if (!file)
+		goto out;
+
+	seq_printf(s, "- ");
+	nfs4_show_stateid(s, &st->sc_stateid);
+	seq_printf(s, ": { type: lock, ");
+
+	/*
+	 * Note: a lock stateid isn't really the same thing as a lock,
+	 * it's the locking state held by one owner on a file, and there
+	 * may be multiple (or no) lock ranges associated with it.
+	 * (Same for the matter is true of open stateids.)
+	 */
+
+	nfs4_show_superblock(s, file);
+	/* XXX: open stateid? */
+	seq_printf(s, ", ");
+	nfs4_show_fname(s, file);
+	seq_printf(s, ", ");
+	nfs4_show_owner(s, oo);
+	seq_printf(s, " }\n");
+out:
+	spin_unlock(&nf->fi_lock);
+	return 0;
+}
+
+static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st)
+{
+	struct nfs4_delegation *ds;
+	struct nfs4_file *nf;
+	struct nfsd_file *file;
+
+	ds = delegstateid(st);
+	nf = st->sc_file;
+	spin_lock(&nf->fi_lock);
+	file = find_deleg_file_locked(nf);
+	if (!file)
+		goto out;
+
+	seq_printf(s, "- ");
+	nfs4_show_stateid(s, &st->sc_stateid);
+	seq_printf(s, ": { type: deleg, ");
+
+	/* Kinda dead code as long as we only support read delegs: */
+	seq_printf(s, "access: %s, ",
+		ds->dl_type == NFS4_OPEN_DELEGATE_READ ? "r" : "w");
+
+	/* XXX: lease time, whether it's being recalled. */
+
+	nfs4_show_superblock(s, file);
+	seq_printf(s, ", ");
+	nfs4_show_fname(s, file);
+	seq_printf(s, " }\n");
+out:
+	spin_unlock(&nf->fi_lock);
+	return 0;
+}
+
+static int nfs4_show_layout(struct seq_file *s, struct nfs4_stid *st)
+{
+	struct nfs4_layout_stateid *ls;
+	struct nfsd_file *file;
+
+	ls = container_of(st, struct nfs4_layout_stateid, ls_stid);
+	file = ls->ls_file;
+
+	seq_printf(s, "- ");
+	nfs4_show_stateid(s, &st->sc_stateid);
+	seq_printf(s, ": { type: layout, ");
+
+	/* XXX: What else would be useful? */
+
+	nfs4_show_superblock(s, file);
+	seq_printf(s, ", ");
+	nfs4_show_fname(s, file);
+	seq_printf(s, " }\n");
+
+	return 0;
+}
+
+static int states_show(struct seq_file *s, void *v)
+{
+	struct nfs4_stid *st = v;
+
+	switch (st->sc_type) {
+	case NFS4_OPEN_STID:
+		return nfs4_show_open(s, st);
+	case NFS4_LOCK_STID:
+		return nfs4_show_lock(s, st);
+	case NFS4_DELEG_STID:
+		return nfs4_show_deleg(s, st);
+	case NFS4_LAYOUT_STID:
+		return nfs4_show_layout(s, st);
+	default:
+		return 0; /* XXX: or SEQ_SKIP? */
+	}
+	/* XXX: copy stateids? */
+}
+
+static struct seq_operations states_seq_ops = {
+	.start = states_start,
+	.next = states_next,
+	.stop = states_stop,
+	.show = states_show
+};
+
+static int client_states_open(struct inode *inode, struct file *file)
+{
+	struct seq_file *s;
+	struct nfs4_client *clp;
+	int ret;
+
+	clp = get_nfsdfs_clp(inode);
+	if (!clp)
+		return -ENXIO;
+
+	ret = seq_open(file, &states_seq_ops);
+	if (ret)
+		return ret;
+	s = file->private_data;
+	s->private = clp;
+	return 0;
+}
+
+static int client_opens_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = file->private_data;
+	struct nfs4_client *clp = m->private;
+
+	/* XXX: alternatively, we could get/drop in seq start/stop */
+	drop_client(clp);
+	return seq_release(inode, file);
+}
+
+static const struct file_operations client_states_fops = {
+	.open		= client_states_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= client_opens_release,
+};
+
+/*
+ * Normally we refuse to destroy clients that are in use, but here the
+ * administrator is telling us to just do it.  We also want to wait
+ * so the caller has a guarantee that the client's locks are gone by
+ * the time the write returns:
+ */
+static void force_expire_client(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	bool already_expired;
+
+	trace_nfsd_clid_admin_expired(&clp->cl_clientid);
+
+	spin_lock(&nn->client_lock);
+	clp->cl_time = 0;
+	spin_unlock(&nn->client_lock);
+
+	wait_event(expiry_wq, atomic_read(&clp->cl_rpc_users) == 0);
+	spin_lock(&nn->client_lock);
+	already_expired = list_empty(&clp->cl_lru);
+	if (!already_expired)
+		unhash_client_locked(clp);
+	spin_unlock(&nn->client_lock);
+
+	if (!already_expired)
+		expire_client(clp);
+	else
+		wait_event(expiry_wq, clp->cl_nfsd_dentry == NULL);
+}
+
+static ssize_t client_ctl_write(struct file *file, const char __user *buf,
+				   size_t size, loff_t *pos)
+{
+	char *data;
+	struct nfs4_client *clp;
+
+	data = simple_transaction_get(file, buf, size);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+	if (size != 7 || 0 != memcmp(data, "expire\n", 7))
+		return -EINVAL;
+	clp = get_nfsdfs_clp(file_inode(file));
+	if (!clp)
+		return -ENXIO;
+	force_expire_client(clp);
+	drop_client(clp);
+	return 7;
+}
+
+static const struct file_operations client_ctl_fops = {
+	.write		= client_ctl_write,
+	.release	= simple_transaction_release,
+};
+
+static const struct tree_descr client_files[] = {
+	[0] = {"info", &client_info_fops, S_IRUSR},
+	[1] = {"states", &client_states_fops, S_IRUSR},
+	[2] = {"ctl", &client_ctl_fops, S_IWUSR},
+	[3] = {""},
+};
+
+static struct nfs4_client *create_client(struct xdr_netobj name,
+		struct svc_rqst *rqstp, nfs4_verifier *verf)
+{
+	struct nfs4_client *clp;
+	struct sockaddr *sa = svc_addr(rqstp);
+	int ret;
+	struct net *net = SVC_NET(rqstp);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct dentry *dentries[ARRAY_SIZE(client_files)];
+
+	clp = alloc_client(name, nn);
+	if (clp == NULL)
+		return NULL;
+
+	ret = copy_cred(&clp->cl_cred, &rqstp->rq_cred);
+	if (ret) {
+		free_client(clp);
+		return NULL;
+	}
+	gen_clid(clp, nn);
+	kref_init(&clp->cl_nfsdfs.cl_ref);
+	nfsd4_init_cb(&clp->cl_cb_null, clp, NULL, NFSPROC4_CLNT_CB_NULL);
+	clp->cl_time = ktime_get_boottime_seconds();
+	clear_bit(0, &clp->cl_cb_slot_busy);
+	copy_verf(clp, verf);
+	memcpy(&clp->cl_addr, sa, sizeof(struct sockaddr_storage));
+	clp->cl_cb_session = NULL;
+	clp->net = net;
+	clp->cl_nfsd_dentry = nfsd_client_mkdir(
+		nn, &clp->cl_nfsdfs,
+		clp->cl_clientid.cl_id - nn->clientid_base,
+		client_files, dentries);
+	clp->cl_nfsd_info_dentry = dentries[0];
+	if (!clp->cl_nfsd_dentry) {
+		free_client(clp);
+		return NULL;
+	}
+	return clp;
+}
+
+static void
+add_clp_to_name_tree(struct nfs4_client *new_clp, struct rb_root *root)
+{
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+	struct nfs4_client *clp;
+
+	while (*new) {
+		clp = rb_entry(*new, struct nfs4_client, cl_namenode);
+		parent = *new;
+
+		if (compare_blob(&clp->cl_name, &new_clp->cl_name) > 0)
+			new = &((*new)->rb_left);
+		else
+			new = &((*new)->rb_right);
+	}
+
+	rb_link_node(&new_clp->cl_namenode, parent, new);
+	rb_insert_color(&new_clp->cl_namenode, root);
+}
+
+static struct nfs4_client *
+find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
+{
+	int cmp;
+	struct rb_node *node = root->rb_node;
+	struct nfs4_client *clp;
+
+	while (node) {
+		clp = rb_entry(node, struct nfs4_client, cl_namenode);
+		cmp = compare_blob(&clp->cl_name, name);
+		if (cmp > 0)
+			node = node->rb_left;
+		else if (cmp < 0)
+			node = node->rb_right;
+		else
+			return clp;
+	}
+	return NULL;
+}
+
+static void
+add_to_unconfirmed(struct nfs4_client *clp)
+{
+	unsigned int idhashval;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	lockdep_assert_held(&nn->client_lock);
+
+	clear_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags);
+	add_clp_to_name_tree(clp, &nn->unconf_name_tree);
+	idhashval = clientid_hashval(clp->cl_clientid.cl_id);
+	list_add(&clp->cl_idhash, &nn->unconf_id_hashtbl[idhashval]);
+	renew_client_locked(clp);
+}
+
+static void
+move_to_confirmed(struct nfs4_client *clp)
+{
+	unsigned int idhashval = clientid_hashval(clp->cl_clientid.cl_id);
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	lockdep_assert_held(&nn->client_lock);
+
+	list_move(&clp->cl_idhash, &nn->conf_id_hashtbl[idhashval]);
+	rb_erase(&clp->cl_namenode, &nn->unconf_name_tree);
+	add_clp_to_name_tree(clp, &nn->conf_name_tree);
+	set_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags);
+	trace_nfsd_clid_confirmed(&clp->cl_clientid);
+	renew_client_locked(clp);
+}
+
+static struct nfs4_client *
+find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
+{
+	struct nfs4_client *clp;
+	unsigned int idhashval = clientid_hashval(clid->cl_id);
+
+	list_for_each_entry(clp, &tbl[idhashval], cl_idhash) {
+		if (same_clid(&clp->cl_clientid, clid)) {
+			if ((bool)clp->cl_minorversion != sessions)
+				return NULL;
+			renew_client_locked(clp);
+			return clp;
+		}
+	}
+	return NULL;
+}
+
+static struct nfs4_client *
+find_confirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn)
+{
+	struct list_head *tbl = nn->conf_id_hashtbl;
+
+	lockdep_assert_held(&nn->client_lock);
+	return find_client_in_id_table(tbl, clid, sessions);
+}
+
+static struct nfs4_client *
+find_unconfirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn)
+{
+	struct list_head *tbl = nn->unconf_id_hashtbl;
+
+	lockdep_assert_held(&nn->client_lock);
+	return find_client_in_id_table(tbl, clid, sessions);
+}
+
+static bool clp_used_exchangeid(struct nfs4_client *clp)
+{
+	return clp->cl_exchange_flags != 0;
+} 
+
+static struct nfs4_client *
+find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
+{
+	lockdep_assert_held(&nn->client_lock);
+	return find_clp_in_name_tree(name, &nn->conf_name_tree);
+}
+
+static struct nfs4_client *
+find_unconfirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
+{
+	lockdep_assert_held(&nn->client_lock);
+	return find_clp_in_name_tree(name, &nn->unconf_name_tree);
+}
+
+static void
+gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se, struct svc_rqst *rqstp)
+{
+	struct nfs4_cb_conn *conn = &clp->cl_cb_conn;
+	struct sockaddr	*sa = svc_addr(rqstp);
+	u32 scopeid = rpc_get_scope_id(sa);
+	unsigned short expected_family;
+
+	/* Currently, we only support tcp and tcp6 for the callback channel */
+	if (se->se_callback_netid_len == 3 &&
+	    !memcmp(se->se_callback_netid_val, "tcp", 3))
+		expected_family = AF_INET;
+	else if (se->se_callback_netid_len == 4 &&
+		 !memcmp(se->se_callback_netid_val, "tcp6", 4))
+		expected_family = AF_INET6;
+	else
+		goto out_err;
+
+	conn->cb_addrlen = rpc_uaddr2sockaddr(clp->net, se->se_callback_addr_val,
+					    se->se_callback_addr_len,
+					    (struct sockaddr *)&conn->cb_addr,
+					    sizeof(conn->cb_addr));
+
+	if (!conn->cb_addrlen || conn->cb_addr.ss_family != expected_family)
+		goto out_err;
+
+	if (conn->cb_addr.ss_family == AF_INET6)
+		((struct sockaddr_in6 *)&conn->cb_addr)->sin6_scope_id = scopeid;
+
+	conn->cb_prog = se->se_callback_prog;
+	conn->cb_ident = se->se_callback_ident;
+	memcpy(&conn->cb_saddr, &rqstp->rq_daddr, rqstp->rq_daddrlen);
+	trace_nfsd_cb_args(clp, conn);
+	return;
+out_err:
+	conn->cb_addr.ss_family = AF_UNSPEC;
+	conn->cb_addrlen = 0;
+	trace_nfsd_cb_nodelegs(clp);
+	return;
+}
+
+/*
+ * Cache a reply. nfsd4_check_resp_size() has bounded the cache size.
+ */
+static void
+nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
+{
+	struct xdr_buf *buf = resp->xdr->buf;
+	struct nfsd4_slot *slot = resp->cstate.slot;
+	unsigned int base;
+
+	dprintk("--> %s slot %p\n", __func__, slot);
+
+	slot->sl_flags |= NFSD4_SLOT_INITIALIZED;
+	slot->sl_opcnt = resp->opcnt;
+	slot->sl_status = resp->cstate.status;
+	free_svc_cred(&slot->sl_cred);
+	copy_cred(&slot->sl_cred, &resp->rqstp->rq_cred);
+
+	if (!nfsd4_cache_this(resp)) {
+		slot->sl_flags &= ~NFSD4_SLOT_CACHED;
+		return;
+	}
+	slot->sl_flags |= NFSD4_SLOT_CACHED;
+
+	base = resp->cstate.data_offset;
+	slot->sl_datalen = buf->len - base;
+	if (read_bytes_from_xdr_buf(buf, base, slot->sl_data, slot->sl_datalen))
+		WARN(1, "%s: sessions DRC could not cache compound\n",
+		     __func__);
+	return;
+}
+
+/*
+ * Encode the replay sequence operation from the slot values.
+ * If cachethis is FALSE encode the uncached rep error on the next
+ * operation which sets resp->p and increments resp->opcnt for
+ * nfs4svc_encode_compoundres.
+ *
+ */
+static __be32
+nfsd4_enc_sequence_replay(struct nfsd4_compoundargs *args,
+			  struct nfsd4_compoundres *resp)
+{
+	struct nfsd4_op *op;
+	struct nfsd4_slot *slot = resp->cstate.slot;
+
+	/* Encode the replayed sequence operation */
+	op = &args->ops[resp->opcnt - 1];
+	nfsd4_encode_operation(resp, op);
+
+	if (slot->sl_flags & NFSD4_SLOT_CACHED)
+		return op->status;
+	if (args->opcnt == 1) {
+		/*
+		 * The original operation wasn't a solo sequence--we
+		 * always cache those--so this retry must not match the
+		 * original:
+		 */
+		op->status = nfserr_seq_false_retry;
+	} else {
+		op = &args->ops[resp->opcnt++];
+		op->status = nfserr_retry_uncached_rep;
+		nfsd4_encode_operation(resp, op);
+	}
+	return op->status;
+}
+
+/*
+ * The sequence operation is not cached because we can use the slot and
+ * session values.
+ */
+static __be32
+nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
+			 struct nfsd4_sequence *seq)
+{
+	struct nfsd4_slot *slot = resp->cstate.slot;
+	struct xdr_stream *xdr = resp->xdr;
+	__be32 *p;
+	__be32 status;
+
+	dprintk("--> %s slot %p\n", __func__, slot);
+
+	status = nfsd4_enc_sequence_replay(resp->rqstp->rq_argp, resp);
+	if (status)
+		return status;
+
+	p = xdr_reserve_space(xdr, slot->sl_datalen);
+	if (!p) {
+		WARN_ON_ONCE(1);
+		return nfserr_serverfault;
+	}
+	xdr_encode_opaque_fixed(p, slot->sl_data, slot->sl_datalen);
+	xdr_commit_encode(xdr);
+
+	resp->opcnt = slot->sl_opcnt;
+	return slot->sl_status;
+}
+
+/*
+ * Set the exchange_id flags returned by the server.
+ */
+static void
+nfsd4_set_ex_flags(struct nfs4_client *new, struct nfsd4_exchange_id *clid)
+{
+#ifdef CONFIG_NFSD_PNFS
+	new->cl_exchange_flags |= EXCHGID4_FLAG_USE_PNFS_MDS;
+#else
+	new->cl_exchange_flags |= EXCHGID4_FLAG_USE_NON_PNFS;
+#endif
+
+	/* Referrals are supported, Migration is not. */
+	new->cl_exchange_flags |= EXCHGID4_FLAG_SUPP_MOVED_REFER;
+
+	/* set the wire flags to return to client. */
+	clid->flags = new->cl_exchange_flags;
+}
+
+static bool client_has_openowners(struct nfs4_client *clp)
+{
+	struct nfs4_openowner *oo;
+
+	list_for_each_entry(oo, &clp->cl_openowners, oo_perclient) {
+		if (!list_empty(&oo->oo_owner.so_stateids))
+			return true;
+	}
+	return false;
+}
+
+static bool client_has_state(struct nfs4_client *clp)
+{
+	return client_has_openowners(clp)
+#ifdef CONFIG_NFSD_PNFS
+		|| !list_empty(&clp->cl_lo_states)
+#endif
+		|| !list_empty(&clp->cl_delegations)
+		|| !list_empty(&clp->cl_sessions)
+		|| !list_empty(&clp->async_copies);
+}
+
+static __be32 copy_impl_id(struct nfs4_client *clp,
+				struct nfsd4_exchange_id *exid)
+{
+	if (!exid->nii_domain.data)
+		return 0;
+	xdr_netobj_dup(&clp->cl_nii_domain, &exid->nii_domain, GFP_KERNEL);
+	if (!clp->cl_nii_domain.data)
+		return nfserr_jukebox;
+	xdr_netobj_dup(&clp->cl_nii_name, &exid->nii_name, GFP_KERNEL);
+	if (!clp->cl_nii_name.data)
+		return nfserr_jukebox;
+	clp->cl_nii_time = exid->nii_time;
+	return 0;
+}
+
+__be32
+nfsd4_exchange_id(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	struct nfsd4_exchange_id *exid = &u->exchange_id;
+	struct nfs4_client *conf, *new;
+	struct nfs4_client *unconf = NULL;
+	__be32 status;
+	char			addr_str[INET6_ADDRSTRLEN];
+	nfs4_verifier		verf = exid->verifier;
+	struct sockaddr		*sa = svc_addr(rqstp);
+	bool	update = exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A;
+	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	rpc_ntop(sa, addr_str, sizeof(addr_str));
+	dprintk("%s rqstp=%p exid=%p clname.len=%u clname.data=%p "
+		"ip_addr=%s flags %x, spa_how %u\n",
+		__func__, rqstp, exid, exid->clname.len, exid->clname.data,
+		addr_str, exid->flags, exid->spa_how);
+
+	if (exid->flags & ~EXCHGID4_FLAG_MASK_A)
+		return nfserr_inval;
+
+	new = create_client(exid->clname, rqstp, &verf);
+	if (new == NULL)
+		return nfserr_jukebox;
+	status = copy_impl_id(new, exid);
+	if (status)
+		goto out_nolock;
+
+	switch (exid->spa_how) {
+	case SP4_MACH_CRED:
+		exid->spo_must_enforce[0] = 0;
+		exid->spo_must_enforce[1] = (
+			1 << (OP_BIND_CONN_TO_SESSION - 32) |
+			1 << (OP_EXCHANGE_ID - 32) |
+			1 << (OP_CREATE_SESSION - 32) |
+			1 << (OP_DESTROY_SESSION - 32) |
+			1 << (OP_DESTROY_CLIENTID - 32));
+
+		exid->spo_must_allow[0] &= (1 << (OP_CLOSE) |
+					1 << (OP_OPEN_DOWNGRADE) |
+					1 << (OP_LOCKU) |
+					1 << (OP_DELEGRETURN));
+
+		exid->spo_must_allow[1] &= (
+					1 << (OP_TEST_STATEID - 32) |
+					1 << (OP_FREE_STATEID - 32));
+		if (!svc_rqst_integrity_protected(rqstp)) {
+			status = nfserr_inval;
+			goto out_nolock;
+		}
+		/*
+		 * Sometimes userspace doesn't give us a principal.
+		 * Which is a bug, really.  Anyway, we can't enforce
+		 * MACH_CRED in that case, better to give up now:
+		 */
+		if (!new->cl_cred.cr_principal &&
+					!new->cl_cred.cr_raw_principal) {
+			status = nfserr_serverfault;
+			goto out_nolock;
+		}
+		new->cl_mach_cred = true;
+		break;
+	case SP4_NONE:
+		break;
+	default:				/* checked by xdr code */
+		WARN_ON_ONCE(1);
+		fallthrough;
+	case SP4_SSV:
+		status = nfserr_encr_alg_unsupp;
+		goto out_nolock;
+	}
+
+	/* Cases below refer to rfc 5661 section 18.35.4: */
+	spin_lock(&nn->client_lock);
+	conf = find_confirmed_client_by_name(&exid->clname, nn);
+	if (conf) {
+		bool creds_match = same_creds(&conf->cl_cred, &rqstp->rq_cred);
+		bool verfs_match = same_verf(&verf, &conf->cl_verifier);
+
+		if (update) {
+			if (!clp_used_exchangeid(conf)) { /* buggy client */
+				status = nfserr_inval;
+				goto out;
+			}
+			if (!nfsd4_mach_creds_match(conf, rqstp)) {
+				status = nfserr_wrong_cred;
+				goto out;
+			}
+			if (!creds_match) { /* case 9 */
+				status = nfserr_perm;
+				goto out;
+			}
+			if (!verfs_match) { /* case 8 */
+				status = nfserr_not_same;
+				goto out;
+			}
+			/* case 6 */
+			exid->flags |= EXCHGID4_FLAG_CONFIRMED_R;
+			trace_nfsd_clid_confirmed_r(conf);
+			goto out_copy;
+		}
+		if (!creds_match) { /* case 3 */
+			if (client_has_state(conf)) {
+				status = nfserr_clid_inuse;
+				trace_nfsd_clid_cred_mismatch(conf, rqstp);
+				goto out;
+			}
+			goto out_new;
+		}
+		if (verfs_match) { /* case 2 */
+			conf->cl_exchange_flags |= EXCHGID4_FLAG_CONFIRMED_R;
+			trace_nfsd_clid_confirmed_r(conf);
+			goto out_copy;
+		}
+		/* case 5, client reboot */
+		trace_nfsd_clid_verf_mismatch(conf, rqstp, &verf);
+		conf = NULL;
+		goto out_new;
+	}
+
+	if (update) { /* case 7 */
+		status = nfserr_noent;
+		goto out;
+	}
+
+	unconf = find_unconfirmed_client_by_name(&exid->clname, nn);
+	if (unconf) /* case 4, possible retry or client restart */
+		unhash_client_locked(unconf);
+
+	/* case 1, new owner ID */
+	trace_nfsd_clid_fresh(new);
+
+out_new:
+	if (conf) {
+		status = mark_client_expired_locked(conf);
+		if (status)
+			goto out;
+		trace_nfsd_clid_replaced(&conf->cl_clientid);
+	}
+	new->cl_minorversion = cstate->minorversion;
+	new->cl_spo_must_allow.u.words[0] = exid->spo_must_allow[0];
+	new->cl_spo_must_allow.u.words[1] = exid->spo_must_allow[1];
+
+	add_to_unconfirmed(new);
+	swap(new, conf);
+out_copy:
+	exid->clientid.cl_boot = conf->cl_clientid.cl_boot;
+	exid->clientid.cl_id = conf->cl_clientid.cl_id;
+
+	exid->seqid = conf->cl_cs_slot.sl_seqid + 1;
+	nfsd4_set_ex_flags(conf, exid);
+
+	dprintk("nfsd4_exchange_id seqid %d flags %x\n",
+		conf->cl_cs_slot.sl_seqid, conf->cl_exchange_flags);
+	status = nfs_ok;
+
+out:
+	spin_unlock(&nn->client_lock);
+out_nolock:
+	if (new)
+		expire_client(new);
+	if (unconf) {
+		trace_nfsd_clid_expire_unconf(&unconf->cl_clientid);
+		expire_client(unconf);
+	}
+	return status;
+}
+
+static __be32
+check_slot_seqid(u32 seqid, u32 slot_seqid, int slot_inuse)
+{
+	dprintk("%s enter. seqid %d slot_seqid %d\n", __func__, seqid,
+		slot_seqid);
+
+	/* The slot is in use, and no response has been sent. */
+	if (slot_inuse) {
+		if (seqid == slot_seqid)
+			return nfserr_jukebox;
+		else
+			return nfserr_seq_misordered;
+	}
+	/* Note unsigned 32-bit arithmetic handles wraparound: */
+	if (likely(seqid == slot_seqid + 1))
+		return nfs_ok;
+	if (seqid == slot_seqid)
+		return nfserr_replay_cache;
+	return nfserr_seq_misordered;
+}
+
+/*
+ * Cache the create session result into the create session single DRC
+ * slot cache by saving the xdr structure. sl_seqid has been set.
+ * Do this for solo or embedded create session operations.
+ */
+static void
+nfsd4_cache_create_session(struct nfsd4_create_session *cr_ses,
+			   struct nfsd4_clid_slot *slot, __be32 nfserr)
+{
+	slot->sl_status = nfserr;
+	memcpy(&slot->sl_cr_ses, cr_ses, sizeof(*cr_ses));
+}
+
+static __be32
+nfsd4_replay_create_session(struct nfsd4_create_session *cr_ses,
+			    struct nfsd4_clid_slot *slot)
+{
+	memcpy(cr_ses, &slot->sl_cr_ses, sizeof(*cr_ses));
+	return slot->sl_status;
+}
+
+#define NFSD_MIN_REQ_HDR_SEQ_SZ	((\
+			2 * 2 + /* credential,verifier: AUTH_NULL, length 0 */ \
+			1 +	/* MIN tag is length with zero, only length */ \
+			3 +	/* version, opcount, opcode */ \
+			XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + \
+				/* seqid, slotID, slotID, cache */ \
+			4 ) * sizeof(__be32))
+
+#define NFSD_MIN_RESP_HDR_SEQ_SZ ((\
+			2 +	/* verifier: AUTH_NULL, length 0 */\
+			1 +	/* status */ \
+			1 +	/* MIN tag is length with zero, only length */ \
+			3 +	/* opcount, opcode, opstatus*/ \
+			XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + \
+				/* seqid, slotID, slotID, slotID, status */ \
+			5 ) * sizeof(__be32))
+
+static __be32 check_forechannel_attrs(struct nfsd4_channel_attrs *ca, struct nfsd_net *nn)
+{
+	u32 maxrpc = nn->nfsd_serv->sv_max_mesg;
+
+	if (ca->maxreq_sz < NFSD_MIN_REQ_HDR_SEQ_SZ)
+		return nfserr_toosmall;
+	if (ca->maxresp_sz < NFSD_MIN_RESP_HDR_SEQ_SZ)
+		return nfserr_toosmall;
+	ca->headerpadsz = 0;
+	ca->maxreq_sz = min_t(u32, ca->maxreq_sz, maxrpc);
+	ca->maxresp_sz = min_t(u32, ca->maxresp_sz, maxrpc);
+	ca->maxops = min_t(u32, ca->maxops, NFSD_MAX_OPS_PER_COMPOUND);
+	ca->maxresp_cached = min_t(u32, ca->maxresp_cached,
+			NFSD_SLOT_CACHE_SIZE + NFSD_MIN_HDR_SEQ_SZ);
+	ca->maxreqs = min_t(u32, ca->maxreqs, NFSD_MAX_SLOTS_PER_SESSION);
+	/*
+	 * Note decreasing slot size below client's request may make it
+	 * difficult for client to function correctly, whereas
+	 * decreasing the number of slots will (just?) affect
+	 * performance.  When short on memory we therefore prefer to
+	 * decrease number of slots instead of their size.  Clients that
+	 * request larger slots than they need will get poor results:
+	 * Note that we always allow at least one slot, because our
+	 * accounting is soft and provides no guarantees either way.
+	 */
+	ca->maxreqs = nfsd4_get_drc_mem(ca, nn);
+
+	return nfs_ok;
+}
+
+/*
+ * Server's NFSv4.1 backchannel support is AUTH_SYS-only for now.
+ * These are based on similar macros in linux/sunrpc/msg_prot.h .
+ */
+#define RPC_MAX_HEADER_WITH_AUTH_SYS \
+	(RPC_CALLHDRSIZE + 2 * (2 + UNX_CALLSLACK))
+
+#define RPC_MAX_REPHEADER_WITH_AUTH_SYS \
+	(RPC_REPHDRSIZE + (2 + NUL_REPLYSLACK))
+
+#define NFSD_CB_MAX_REQ_SZ	((NFS4_enc_cb_recall_sz + \
+				 RPC_MAX_HEADER_WITH_AUTH_SYS) * sizeof(__be32))
+#define NFSD_CB_MAX_RESP_SZ	((NFS4_dec_cb_recall_sz + \
+				 RPC_MAX_REPHEADER_WITH_AUTH_SYS) * \
+				 sizeof(__be32))
+
+static __be32 check_backchannel_attrs(struct nfsd4_channel_attrs *ca)
+{
+	ca->headerpadsz = 0;
+
+	if (ca->maxreq_sz < NFSD_CB_MAX_REQ_SZ)
+		return nfserr_toosmall;
+	if (ca->maxresp_sz < NFSD_CB_MAX_RESP_SZ)
+		return nfserr_toosmall;
+	ca->maxresp_cached = 0;
+	if (ca->maxops < 2)
+		return nfserr_toosmall;
+
+	return nfs_ok;
+}
+
+static __be32 nfsd4_check_cb_sec(struct nfsd4_cb_sec *cbs)
+{
+	switch (cbs->flavor) {
+	case RPC_AUTH_NULL:
+	case RPC_AUTH_UNIX:
+		return nfs_ok;
+	default:
+		/*
+		 * GSS case: the spec doesn't allow us to return this
+		 * error.  But it also doesn't allow us not to support
+		 * GSS.
+		 * I'd rather this fail hard than return some error the
+		 * client might think it can already handle:
+		 */
+		return nfserr_encr_alg_unsupp;
+	}
+}
+
+__be32
+nfsd4_create_session(struct svc_rqst *rqstp,
+		struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
+{
+	struct nfsd4_create_session *cr_ses = &u->create_session;
+	struct sockaddr *sa = svc_addr(rqstp);
+	struct nfs4_client *conf, *unconf;
+	struct nfs4_client *old = NULL;
+	struct nfsd4_session *new;
+	struct nfsd4_conn *conn;
+	struct nfsd4_clid_slot *cs_slot = NULL;
+	__be32 status = 0;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	if (cr_ses->flags & ~SESSION4_FLAG_MASK_A)
+		return nfserr_inval;
+	status = nfsd4_check_cb_sec(&cr_ses->cb_sec);
+	if (status)
+		return status;
+	status = check_forechannel_attrs(&cr_ses->fore_channel, nn);
+	if (status)
+		return status;
+	status = check_backchannel_attrs(&cr_ses->back_channel);
+	if (status)
+		goto out_release_drc_mem;
+	status = nfserr_jukebox;
+	new = alloc_session(&cr_ses->fore_channel, &cr_ses->back_channel);
+	if (!new)
+		goto out_release_drc_mem;
+	conn = alloc_conn_from_crses(rqstp, cr_ses);
+	if (!conn)
+		goto out_free_session;
+
+	spin_lock(&nn->client_lock);
+	unconf = find_unconfirmed_client(&cr_ses->clientid, true, nn);
+	conf = find_confirmed_client(&cr_ses->clientid, true, nn);
+	WARN_ON_ONCE(conf && unconf);
+
+	if (conf) {
+		status = nfserr_wrong_cred;
+		if (!nfsd4_mach_creds_match(conf, rqstp))
+			goto out_free_conn;
+		cs_slot = &conf->cl_cs_slot;
+		status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0);
+		if (status) {
+			if (status == nfserr_replay_cache)
+				status = nfsd4_replay_create_session(cr_ses, cs_slot);
+			goto out_free_conn;
+		}
+	} else if (unconf) {
+		status = nfserr_clid_inuse;
+		if (!same_creds(&unconf->cl_cred, &rqstp->rq_cred) ||
+		    !rpc_cmp_addr(sa, (struct sockaddr *) &unconf->cl_addr)) {
+			trace_nfsd_clid_cred_mismatch(unconf, rqstp);
+			goto out_free_conn;
+		}
+		status = nfserr_wrong_cred;
+		if (!nfsd4_mach_creds_match(unconf, rqstp))
+			goto out_free_conn;
+		cs_slot = &unconf->cl_cs_slot;
+		status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0);
+		if (status) {
+			/* an unconfirmed replay returns misordered */
+			status = nfserr_seq_misordered;
+			goto out_free_conn;
+		}
+		old = find_confirmed_client_by_name(&unconf->cl_name, nn);
+		if (old) {
+			status = mark_client_expired_locked(old);
+			if (status) {
+				old = NULL;
+				goto out_free_conn;
+			}
+			trace_nfsd_clid_replaced(&old->cl_clientid);
+		}
+		move_to_confirmed(unconf);
+		conf = unconf;
+	} else {
+		status = nfserr_stale_clientid;
+		goto out_free_conn;
+	}
+	status = nfs_ok;
+	/* Persistent sessions are not supported */
+	cr_ses->flags &= ~SESSION4_PERSIST;
+	/* Upshifting from TCP to RDMA is not supported */
+	cr_ses->flags &= ~SESSION4_RDMA;
+
+	init_session(rqstp, new, conf, cr_ses);
+	nfsd4_get_session_locked(new);
+
+	memcpy(cr_ses->sessionid.data, new->se_sessionid.data,
+	       NFS4_MAX_SESSIONID_LEN);
+	cs_slot->sl_seqid++;
+	cr_ses->seqid = cs_slot->sl_seqid;
+
+	/* cache solo and embedded create sessions under the client_lock */
+	nfsd4_cache_create_session(cr_ses, cs_slot, status);
+	spin_unlock(&nn->client_lock);
+	if (conf == unconf)
+		fsnotify_dentry(conf->cl_nfsd_info_dentry, FS_MODIFY);
+	/* init connection and backchannel */
+	nfsd4_init_conn(rqstp, conn, new);
+	nfsd4_put_session(new);
+	if (old)
+		expire_client(old);
+	return status;
+out_free_conn:
+	spin_unlock(&nn->client_lock);
+	free_conn(conn);
+	if (old)
+		expire_client(old);
+out_free_session:
+	__free_session(new);
+out_release_drc_mem:
+	nfsd4_put_drc_mem(&cr_ses->fore_channel);
+	return status;
+}
+
+static __be32 nfsd4_map_bcts_dir(u32 *dir)
+{
+	switch (*dir) {
+	case NFS4_CDFC4_FORE:
+	case NFS4_CDFC4_BACK:
+		return nfs_ok;
+	case NFS4_CDFC4_FORE_OR_BOTH:
+	case NFS4_CDFC4_BACK_OR_BOTH:
+		*dir = NFS4_CDFC4_BOTH;
+		return nfs_ok;
+	}
+	return nfserr_inval;
+}
+
+__be32 nfsd4_backchannel_ctl(struct svc_rqst *rqstp,
+		struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	struct nfsd4_backchannel_ctl *bc = &u->backchannel_ctl;
+	struct nfsd4_session *session = cstate->session;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+	__be32 status;
+
+	status = nfsd4_check_cb_sec(&bc->bc_cb_sec);
+	if (status)
+		return status;
+	spin_lock(&nn->client_lock);
+	session->se_cb_prog = bc->bc_cb_program;
+	session->se_cb_sec = bc->bc_cb_sec;
+	spin_unlock(&nn->client_lock);
+
+	nfsd4_probe_callback(session->se_client);
+
+	return nfs_ok;
+}
+
+static struct nfsd4_conn *__nfsd4_find_conn(struct svc_xprt *xpt, struct nfsd4_session *s)
+{
+	struct nfsd4_conn *c;
+
+	list_for_each_entry(c, &s->se_conns, cn_persession) {
+		if (c->cn_xprt == xpt) {
+			return c;
+		}
+	}
+	return NULL;
+}
+
+static __be32 nfsd4_match_existing_connection(struct svc_rqst *rqst,
+		struct nfsd4_session *session, u32 req, struct nfsd4_conn **conn)
+{
+	struct nfs4_client *clp = session->se_client;
+	struct svc_xprt *xpt = rqst->rq_xprt;
+	struct nfsd4_conn *c;
+	__be32 status;
+
+	/* Following the last paragraph of RFC 5661 Section 18.34.3: */
+	spin_lock(&clp->cl_lock);
+	c = __nfsd4_find_conn(xpt, session);
+	if (!c)
+		status = nfserr_noent;
+	else if (req == c->cn_flags)
+		status = nfs_ok;
+	else if (req == NFS4_CDFC4_FORE_OR_BOTH &&
+				c->cn_flags != NFS4_CDFC4_BACK)
+		status = nfs_ok;
+	else if (req == NFS4_CDFC4_BACK_OR_BOTH &&
+				c->cn_flags != NFS4_CDFC4_FORE)
+		status = nfs_ok;
+	else
+		status = nfserr_inval;
+	spin_unlock(&clp->cl_lock);
+	if (status == nfs_ok && conn)
+		*conn = c;
+	return status;
+}
+
+__be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
+		     struct nfsd4_compound_state *cstate,
+		     union nfsd4_op_u *u)
+{
+	struct nfsd4_bind_conn_to_session *bcts = &u->bind_conn_to_session;
+	__be32 status;
+	struct nfsd4_conn *conn;
+	struct nfsd4_session *session;
+	struct net *net = SVC_NET(rqstp);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (!nfsd4_last_compound_op(rqstp))
+		return nfserr_not_only_op;
+	spin_lock(&nn->client_lock);
+	session = find_in_sessionid_hashtbl(&bcts->sessionid, net, &status);
+	spin_unlock(&nn->client_lock);
+	if (!session)
+		goto out_no_session;
+	status = nfserr_wrong_cred;
+	if (!nfsd4_mach_creds_match(session->se_client, rqstp))
+		goto out;
+	status = nfsd4_match_existing_connection(rqstp, session,
+			bcts->dir, &conn);
+	if (status == nfs_ok) {
+		if (bcts->dir == NFS4_CDFC4_FORE_OR_BOTH ||
+				bcts->dir == NFS4_CDFC4_BACK)
+			conn->cn_flags |= NFS4_CDFC4_BACK;
+		nfsd4_probe_callback(session->se_client);
+		goto out;
+	}
+	if (status == nfserr_inval)
+		goto out;
+	status = nfsd4_map_bcts_dir(&bcts->dir);
+	if (status)
+		goto out;
+	conn = alloc_conn(rqstp, bcts->dir);
+	status = nfserr_jukebox;
+	if (!conn)
+		goto out;
+	nfsd4_init_conn(rqstp, conn, session);
+	status = nfs_ok;
+out:
+	nfsd4_put_session(session);
+out_no_session:
+	return status;
+}
+
+static bool nfsd4_compound_in_session(struct nfsd4_compound_state *cstate, struct nfs4_sessionid *sid)
+{
+	if (!cstate->session)
+		return false;
+	return !memcmp(sid, &cstate->session->se_sessionid, sizeof(*sid));
+}
+
+__be32
+nfsd4_destroy_session(struct svc_rqst *r, struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	struct nfs4_sessionid *sessionid = &u->destroy_session.sessionid;
+	struct nfsd4_session *ses;
+	__be32 status;
+	int ref_held_by_me = 0;
+	struct net *net = SVC_NET(r);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	status = nfserr_not_only_op;
+	if (nfsd4_compound_in_session(cstate, sessionid)) {
+		if (!nfsd4_last_compound_op(r))
+			goto out;
+		ref_held_by_me++;
+	}
+	dump_sessionid(__func__, sessionid);
+	spin_lock(&nn->client_lock);
+	ses = find_in_sessionid_hashtbl(sessionid, net, &status);
+	if (!ses)
+		goto out_client_lock;
+	status = nfserr_wrong_cred;
+	if (!nfsd4_mach_creds_match(ses->se_client, r))
+		goto out_put_session;
+	status = mark_session_dead_locked(ses, 1 + ref_held_by_me);
+	if (status)
+		goto out_put_session;
+	unhash_session(ses);
+	spin_unlock(&nn->client_lock);
+
+	nfsd4_probe_callback_sync(ses->se_client);
+
+	spin_lock(&nn->client_lock);
+	status = nfs_ok;
+out_put_session:
+	nfsd4_put_session_locked(ses);
+out_client_lock:
+	spin_unlock(&nn->client_lock);
+out:
+	return status;
+}
+
+static __be32 nfsd4_sequence_check_conn(struct nfsd4_conn *new, struct nfsd4_session *ses)
+{
+	struct nfs4_client *clp = ses->se_client;
+	struct nfsd4_conn *c;
+	__be32 status = nfs_ok;
+	int ret;
+
+	spin_lock(&clp->cl_lock);
+	c = __nfsd4_find_conn(new->cn_xprt, ses);
+	if (c)
+		goto out_free;
+	status = nfserr_conn_not_bound_to_session;
+	if (clp->cl_mach_cred)
+		goto out_free;
+	__nfsd4_hash_conn(new, ses);
+	spin_unlock(&clp->cl_lock);
+	ret = nfsd4_register_conn(new);
+	if (ret)
+		/* oops; xprt is already down: */
+		nfsd4_conn_lost(&new->cn_xpt_user);
+	return nfs_ok;
+out_free:
+	spin_unlock(&clp->cl_lock);
+	free_conn(new);
+	return status;
+}
+
+static bool nfsd4_session_too_many_ops(struct svc_rqst *rqstp, struct nfsd4_session *session)
+{
+	struct nfsd4_compoundargs *args = rqstp->rq_argp;
+
+	return args->opcnt > session->se_fchannel.maxops;
+}
+
+static bool nfsd4_request_too_big(struct svc_rqst *rqstp,
+				  struct nfsd4_session *session)
+{
+	struct xdr_buf *xb = &rqstp->rq_arg;
+
+	return xb->len > session->se_fchannel.maxreq_sz;
+}
+
+static bool replay_matches_cache(struct svc_rqst *rqstp,
+		 struct nfsd4_sequence *seq, struct nfsd4_slot *slot)
+{
+	struct nfsd4_compoundargs *argp = rqstp->rq_argp;
+
+	if ((bool)(slot->sl_flags & NFSD4_SLOT_CACHETHIS) !=
+	    (bool)seq->cachethis)
+		return false;
+	/*
+	 * If there's an error then the reply can have fewer ops than
+	 * the call.
+	 */
+	if (slot->sl_opcnt < argp->opcnt && !slot->sl_status)
+		return false;
+	/*
+	 * But if we cached a reply with *more* ops than the call you're
+	 * sending us now, then this new call is clearly not really a
+	 * replay of the old one:
+	 */
+	if (slot->sl_opcnt > argp->opcnt)
+		return false;
+	/* This is the only check explicitly called by spec: */
+	if (!same_creds(&rqstp->rq_cred, &slot->sl_cred))
+		return false;
+	/*
+	 * There may be more comparisons we could actually do, but the
+	 * spec doesn't require us to catch every case where the calls
+	 * don't match (that would require caching the call as well as
+	 * the reply), so we don't bother.
+	 */
+	return true;
+}
+
+__be32
+nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	struct nfsd4_sequence *seq = &u->sequence;
+	struct nfsd4_compoundres *resp = rqstp->rq_resp;
+	struct xdr_stream *xdr = resp->xdr;
+	struct nfsd4_session *session;
+	struct nfs4_client *clp;
+	struct nfsd4_slot *slot;
+	struct nfsd4_conn *conn;
+	__be32 status;
+	int buflen;
+	struct net *net = SVC_NET(rqstp);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (resp->opcnt != 1)
+		return nfserr_sequence_pos;
+
+	/*
+	 * Will be either used or freed by nfsd4_sequence_check_conn
+	 * below.
+	 */
+	conn = alloc_conn(rqstp, NFS4_CDFC4_FORE);
+	if (!conn)
+		return nfserr_jukebox;
+
+	spin_lock(&nn->client_lock);
+	session = find_in_sessionid_hashtbl(&seq->sessionid, net, &status);
+	if (!session)
+		goto out_no_session;
+	clp = session->se_client;
+
+	status = nfserr_too_many_ops;
+	if (nfsd4_session_too_many_ops(rqstp, session))
+		goto out_put_session;
+
+	status = nfserr_req_too_big;
+	if (nfsd4_request_too_big(rqstp, session))
+		goto out_put_session;
+
+	status = nfserr_badslot;
+	if (seq->slotid >= session->se_fchannel.maxreqs)
+		goto out_put_session;
+
+	slot = session->se_slots[seq->slotid];
+	dprintk("%s: slotid %d\n", __func__, seq->slotid);
+
+	/* We do not negotiate the number of slots yet, so set the
+	 * maxslots to the session maxreqs which is used to encode
+	 * sr_highest_slotid and the sr_target_slot id to maxslots */
+	seq->maxslots = session->se_fchannel.maxreqs;
+
+	status = check_slot_seqid(seq->seqid, slot->sl_seqid,
+					slot->sl_flags & NFSD4_SLOT_INUSE);
+	if (status == nfserr_replay_cache) {
+		status = nfserr_seq_misordered;
+		if (!(slot->sl_flags & NFSD4_SLOT_INITIALIZED))
+			goto out_put_session;
+		status = nfserr_seq_false_retry;
+		if (!replay_matches_cache(rqstp, seq, slot))
+			goto out_put_session;
+		cstate->slot = slot;
+		cstate->session = session;
+		cstate->clp = clp;
+		/* Return the cached reply status and set cstate->status
+		 * for nfsd4_proc_compound processing */
+		status = nfsd4_replay_cache_entry(resp, seq);
+		cstate->status = nfserr_replay_cache;
+		goto out;
+	}
+	if (status)
+		goto out_put_session;
+
+	status = nfsd4_sequence_check_conn(conn, session);
+	conn = NULL;
+	if (status)
+		goto out_put_session;
+
+	buflen = (seq->cachethis) ?
+			session->se_fchannel.maxresp_cached :
+			session->se_fchannel.maxresp_sz;
+	status = (seq->cachethis) ? nfserr_rep_too_big_to_cache :
+				    nfserr_rep_too_big;
+	if (xdr_restrict_buflen(xdr, buflen - rqstp->rq_auth_slack))
+		goto out_put_session;
+	svc_reserve(rqstp, buflen);
+
+	status = nfs_ok;
+	/* Success! bump slot seqid */
+	slot->sl_seqid = seq->seqid;
+	slot->sl_flags |= NFSD4_SLOT_INUSE;
+	if (seq->cachethis)
+		slot->sl_flags |= NFSD4_SLOT_CACHETHIS;
+	else
+		slot->sl_flags &= ~NFSD4_SLOT_CACHETHIS;
+
+	cstate->slot = slot;
+	cstate->session = session;
+	cstate->clp = clp;
+
+out:
+	switch (clp->cl_cb_state) {
+	case NFSD4_CB_DOWN:
+		seq->status_flags = SEQ4_STATUS_CB_PATH_DOWN;
+		break;
+	case NFSD4_CB_FAULT:
+		seq->status_flags = SEQ4_STATUS_BACKCHANNEL_FAULT;
+		break;
+	default:
+		seq->status_flags = 0;
+	}
+	if (!list_empty(&clp->cl_revoked))
+		seq->status_flags |= SEQ4_STATUS_RECALLABLE_STATE_REVOKED;
+out_no_session:
+	if (conn)
+		free_conn(conn);
+	spin_unlock(&nn->client_lock);
+	return status;
+out_put_session:
+	nfsd4_put_session_locked(session);
+	goto out_no_session;
+}
+
+void
+nfsd4_sequence_done(struct nfsd4_compoundres *resp)
+{
+	struct nfsd4_compound_state *cs = &resp->cstate;
+
+	if (nfsd4_has_session(cs)) {
+		if (cs->status != nfserr_replay_cache) {
+			nfsd4_store_cache_entry(resp);
+			cs->slot->sl_flags &= ~NFSD4_SLOT_INUSE;
+		}
+		/* Drop session reference that was taken in nfsd4_sequence() */
+		nfsd4_put_session(cs->session);
+	} else if (cs->clp)
+		put_client_renew(cs->clp);
+}
+
+__be32
+nfsd4_destroy_clientid(struct svc_rqst *rqstp,
+		struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	struct nfsd4_destroy_clientid *dc = &u->destroy_clientid;
+	struct nfs4_client *conf, *unconf;
+	struct nfs4_client *clp = NULL;
+	__be32 status = 0;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	spin_lock(&nn->client_lock);
+	unconf = find_unconfirmed_client(&dc->clientid, true, nn);
+	conf = find_confirmed_client(&dc->clientid, true, nn);
+	WARN_ON_ONCE(conf && unconf);
+
+	if (conf) {
+		if (client_has_state(conf)) {
+			status = nfserr_clientid_busy;
+			goto out;
+		}
+		status = mark_client_expired_locked(conf);
+		if (status)
+			goto out;
+		clp = conf;
+	} else if (unconf)
+		clp = unconf;
+	else {
+		status = nfserr_stale_clientid;
+		goto out;
+	}
+	if (!nfsd4_mach_creds_match(clp, rqstp)) {
+		clp = NULL;
+		status = nfserr_wrong_cred;
+		goto out;
+	}
+	trace_nfsd_clid_destroyed(&clp->cl_clientid);
+	unhash_client_locked(clp);
+out:
+	spin_unlock(&nn->client_lock);
+	if (clp)
+		expire_client(clp);
+	return status;
+}
+
+__be32
+nfsd4_reclaim_complete(struct svc_rqst *rqstp,
+		struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
+{
+	struct nfsd4_reclaim_complete *rc = &u->reclaim_complete;
+	struct nfs4_client *clp = cstate->clp;
+	__be32 status = 0;
+
+	if (rc->rca_one_fs) {
+		if (!cstate->current_fh.fh_dentry)
+			return nfserr_nofilehandle;
+		/*
+		 * We don't take advantage of the rca_one_fs case.
+		 * That's OK, it's optional, we can safely ignore it.
+		 */
+		return nfs_ok;
+	}
+
+	status = nfserr_complete_already;
+	if (test_and_set_bit(NFSD4_CLIENT_RECLAIM_COMPLETE, &clp->cl_flags))
+		goto out;
+
+	status = nfserr_stale_clientid;
+	if (is_client_expired(clp))
+		/*
+		 * The following error isn't really legal.
+		 * But we only get here if the client just explicitly
+		 * destroyed the client.  Surely it no longer cares what
+		 * error it gets back on an operation for the dead
+		 * client.
+		 */
+		goto out;
+
+	status = nfs_ok;
+	trace_nfsd_clid_reclaim_complete(&clp->cl_clientid);
+	nfsd4_client_record_create(clp);
+	inc_reclaim_complete(clp);
+out:
+	return status;
+}
+
+__be32
+nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		  union nfsd4_op_u *u)
+{
+	struct nfsd4_setclientid *setclid = &u->setclientid;
+	struct xdr_netobj 	clname = setclid->se_name;
+	nfs4_verifier		clverifier = setclid->se_verf;
+	struct nfs4_client	*conf, *new;
+	struct nfs4_client	*unconf = NULL;
+	__be32 			status;
+	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	new = create_client(clname, rqstp, &clverifier);
+	if (new == NULL)
+		return nfserr_jukebox;
+	spin_lock(&nn->client_lock);
+	conf = find_confirmed_client_by_name(&clname, nn);
+	if (conf && client_has_state(conf)) {
+		status = nfserr_clid_inuse;
+		if (clp_used_exchangeid(conf))
+			goto out;
+		if (!same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
+			trace_nfsd_clid_cred_mismatch(conf, rqstp);
+			goto out;
+		}
+	}
+	unconf = find_unconfirmed_client_by_name(&clname, nn);
+	if (unconf)
+		unhash_client_locked(unconf);
+	if (conf) {
+		if (same_verf(&conf->cl_verifier, &clverifier)) {
+			copy_clid(new, conf);
+			gen_confirm(new, nn);
+		} else
+			trace_nfsd_clid_verf_mismatch(conf, rqstp,
+						      &clverifier);
+	} else
+		trace_nfsd_clid_fresh(new);
+	new->cl_minorversion = 0;
+	gen_callback(new, setclid, rqstp);
+	add_to_unconfirmed(new);
+	setclid->se_clientid.cl_boot = new->cl_clientid.cl_boot;
+	setclid->se_clientid.cl_id = new->cl_clientid.cl_id;
+	memcpy(setclid->se_confirm.data, new->cl_confirm.data, sizeof(setclid->se_confirm.data));
+	new = NULL;
+	status = nfs_ok;
+out:
+	spin_unlock(&nn->client_lock);
+	if (new)
+		free_client(new);
+	if (unconf) {
+		trace_nfsd_clid_expire_unconf(&unconf->cl_clientid);
+		expire_client(unconf);
+	}
+	return status;
+}
+
+__be32
+nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
+			struct nfsd4_compound_state *cstate,
+			union nfsd4_op_u *u)
+{
+	struct nfsd4_setclientid_confirm *setclientid_confirm =
+			&u->setclientid_confirm;
+	struct nfs4_client *conf, *unconf;
+	struct nfs4_client *old = NULL;
+	nfs4_verifier confirm = setclientid_confirm->sc_confirm; 
+	clientid_t * clid = &setclientid_confirm->sc_clientid;
+	__be32 status;
+	struct nfsd_net	*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	if (STALE_CLIENTID(clid, nn))
+		return nfserr_stale_clientid;
+
+	spin_lock(&nn->client_lock);
+	conf = find_confirmed_client(clid, false, nn);
+	unconf = find_unconfirmed_client(clid, false, nn);
+	/*
+	 * We try hard to give out unique clientid's, so if we get an
+	 * attempt to confirm the same clientid with a different cred,
+	 * the client may be buggy; this should never happen.
+	 *
+	 * Nevertheless, RFC 7530 recommends INUSE for this case:
+	 */
+	status = nfserr_clid_inuse;
+	if (unconf && !same_creds(&unconf->cl_cred, &rqstp->rq_cred)) {
+		trace_nfsd_clid_cred_mismatch(unconf, rqstp);
+		goto out;
+	}
+	if (conf && !same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
+		trace_nfsd_clid_cred_mismatch(conf, rqstp);
+		goto out;
+	}
+	if (!unconf || !same_verf(&confirm, &unconf->cl_confirm)) {
+		if (conf && same_verf(&confirm, &conf->cl_confirm)) {
+			status = nfs_ok;
+		} else
+			status = nfserr_stale_clientid;
+		goto out;
+	}
+	status = nfs_ok;
+	if (conf) {
+		old = unconf;
+		unhash_client_locked(old);
+		nfsd4_change_callback(conf, &unconf->cl_cb_conn);
+	} else {
+		old = find_confirmed_client_by_name(&unconf->cl_name, nn);
+		if (old) {
+			status = nfserr_clid_inuse;
+			if (client_has_state(old)
+					&& !same_creds(&unconf->cl_cred,
+							&old->cl_cred)) {
+				old = NULL;
+				goto out;
+			}
+			status = mark_client_expired_locked(old);
+			if (status) {
+				old = NULL;
+				goto out;
+			}
+			trace_nfsd_clid_replaced(&old->cl_clientid);
+		}
+		move_to_confirmed(unconf);
+		conf = unconf;
+	}
+	get_client_locked(conf);
+	spin_unlock(&nn->client_lock);
+	if (conf == unconf)
+		fsnotify_dentry(conf->cl_nfsd_info_dentry, FS_MODIFY);
+	nfsd4_probe_callback(conf);
+	spin_lock(&nn->client_lock);
+	put_client_renew_locked(conf);
+out:
+	spin_unlock(&nn->client_lock);
+	if (old)
+		expire_client(old);
+	return status;
+}
+
+static struct nfs4_file *nfsd4_alloc_file(void)
+{
+	return kmem_cache_alloc(file_slab, GFP_KERNEL);
+}
+
+/* OPEN Share state helper functions */
+static void nfsd4_init_file(struct svc_fh *fh, unsigned int hashval,
+				struct nfs4_file *fp)
+{
+	lockdep_assert_held(&state_lock);
+
+	refcount_set(&fp->fi_ref, 1);
+	spin_lock_init(&fp->fi_lock);
+	INIT_LIST_HEAD(&fp->fi_stateids);
+	INIT_LIST_HEAD(&fp->fi_delegations);
+	INIT_LIST_HEAD(&fp->fi_clnt_odstate);
+	fh_copy_shallow(&fp->fi_fhandle, &fh->fh_handle);
+	fp->fi_deleg_file = NULL;
+	fp->fi_had_conflict = false;
+	fp->fi_share_deny = 0;
+	memset(fp->fi_fds, 0, sizeof(fp->fi_fds));
+	memset(fp->fi_access, 0, sizeof(fp->fi_access));
+	fp->fi_aliased = false;
+	fp->fi_inode = d_inode(fh->fh_dentry);
+#ifdef CONFIG_NFSD_PNFS
+	INIT_LIST_HEAD(&fp->fi_lo_states);
+	atomic_set(&fp->fi_lo_recalls, 0);
+#endif
+	hlist_add_head_rcu(&fp->fi_hash, &file_hashtbl[hashval]);
+}
+
+void
+nfsd4_free_slabs(void)
+{
+	kmem_cache_destroy(client_slab);
+	kmem_cache_destroy(openowner_slab);
+	kmem_cache_destroy(lockowner_slab);
+	kmem_cache_destroy(file_slab);
+	kmem_cache_destroy(stateid_slab);
+	kmem_cache_destroy(deleg_slab);
+	kmem_cache_destroy(odstate_slab);
+}
+
+int
+nfsd4_init_slabs(void)
+{
+	client_slab = kmem_cache_create("nfsd4_clients",
+			sizeof(struct nfs4_client), 0, 0, NULL);
+	if (client_slab == NULL)
+		goto out;
+	openowner_slab = kmem_cache_create("nfsd4_openowners",
+			sizeof(struct nfs4_openowner), 0, 0, NULL);
+	if (openowner_slab == NULL)
+		goto out_free_client_slab;
+	lockowner_slab = kmem_cache_create("nfsd4_lockowners",
+			sizeof(struct nfs4_lockowner), 0, 0, NULL);
+	if (lockowner_slab == NULL)
+		goto out_free_openowner_slab;
+	file_slab = kmem_cache_create("nfsd4_files",
+			sizeof(struct nfs4_file), 0, 0, NULL);
+	if (file_slab == NULL)
+		goto out_free_lockowner_slab;
+	stateid_slab = kmem_cache_create("nfsd4_stateids",
+			sizeof(struct nfs4_ol_stateid), 0, 0, NULL);
+	if (stateid_slab == NULL)
+		goto out_free_file_slab;
+	deleg_slab = kmem_cache_create("nfsd4_delegations",
+			sizeof(struct nfs4_delegation), 0, 0, NULL);
+	if (deleg_slab == NULL)
+		goto out_free_stateid_slab;
+	odstate_slab = kmem_cache_create("nfsd4_odstate",
+			sizeof(struct nfs4_clnt_odstate), 0, 0, NULL);
+	if (odstate_slab == NULL)
+		goto out_free_deleg_slab;
+	return 0;
+
+out_free_deleg_slab:
+	kmem_cache_destroy(deleg_slab);
+out_free_stateid_slab:
+	kmem_cache_destroy(stateid_slab);
+out_free_file_slab:
+	kmem_cache_destroy(file_slab);
+out_free_lockowner_slab:
+	kmem_cache_destroy(lockowner_slab);
+out_free_openowner_slab:
+	kmem_cache_destroy(openowner_slab);
+out_free_client_slab:
+	kmem_cache_destroy(client_slab);
+out:
+	return -ENOMEM;
+}
+
+static unsigned long
+nfsd_courtesy_client_count(struct shrinker *shrink, struct shrink_control *sc)
+{
+	int cnt;
+	struct nfsd_net *nn = container_of(shrink,
+			struct nfsd_net, nfsd_client_shrinker);
+
+	cnt = atomic_read(&nn->nfsd_courtesy_clients);
+	if (cnt > 0)
+		mod_delayed_work(laundry_wq, &nn->nfsd_shrinker_work, 0);
+	return (unsigned long)cnt;
+}
+
+static unsigned long
+nfsd_courtesy_client_scan(struct shrinker *shrink, struct shrink_control *sc)
+{
+	return SHRINK_STOP;
+}
+
+int
+nfsd4_init_leases_net(struct nfsd_net *nn)
+{
+	struct sysinfo si;
+	u64 max_clients;
+
+	nn->nfsd4_lease = 90;	/* default lease time */
+	nn->nfsd4_grace = 90;
+	nn->somebody_reclaimed = false;
+	nn->track_reclaim_completes = false;
+	nn->clverifier_counter = get_random_u32();
+	nn->clientid_base = get_random_u32();
+	nn->clientid_counter = nn->clientid_base + 1;
+	nn->s2s_cp_cl_id = nn->clientid_counter++;
+
+	atomic_set(&nn->nfs4_client_count, 0);
+	si_meminfo(&si);
+	max_clients = (u64)si.totalram * si.mem_unit / (1024 * 1024 * 1024);
+	max_clients *= NFS4_CLIENTS_PER_GB;
+	nn->nfs4_max_clients = max_t(int, max_clients, NFS4_CLIENTS_PER_GB);
+
+	atomic_set(&nn->nfsd_courtesy_clients, 0);
+	nn->nfsd_client_shrinker.scan_objects = nfsd_courtesy_client_scan;
+	nn->nfsd_client_shrinker.count_objects = nfsd_courtesy_client_count;
+	nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS;
+	return register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client");
+}
+
+void
+nfsd4_leases_net_shutdown(struct nfsd_net *nn)
+{
+	unregister_shrinker(&nn->nfsd_client_shrinker);
+}
+
+static void init_nfs4_replay(struct nfs4_replay *rp)
+{
+	rp->rp_status = nfserr_serverfault;
+	rp->rp_buflen = 0;
+	rp->rp_buf = rp->rp_ibuf;
+	mutex_init(&rp->rp_mutex);
+}
+
+static void nfsd4_cstate_assign_replay(struct nfsd4_compound_state *cstate,
+		struct nfs4_stateowner *so)
+{
+	if (!nfsd4_has_session(cstate)) {
+		mutex_lock(&so->so_replay.rp_mutex);
+		cstate->replay_owner = nfs4_get_stateowner(so);
+	}
+}
+
+void nfsd4_cstate_clear_replay(struct nfsd4_compound_state *cstate)
+{
+	struct nfs4_stateowner *so = cstate->replay_owner;
+
+	if (so != NULL) {
+		cstate->replay_owner = NULL;
+		mutex_unlock(&so->so_replay.rp_mutex);
+		nfs4_put_stateowner(so);
+	}
+}
+
+static inline void *alloc_stateowner(struct kmem_cache *slab, struct xdr_netobj *owner, struct nfs4_client *clp)
+{
+	struct nfs4_stateowner *sop;
+
+	sop = kmem_cache_alloc(slab, GFP_KERNEL);
+	if (!sop)
+		return NULL;
+
+	xdr_netobj_dup(&sop->so_owner, owner, GFP_KERNEL);
+	if (!sop->so_owner.data) {
+		kmem_cache_free(slab, sop);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&sop->so_stateids);
+	sop->so_client = clp;
+	init_nfs4_replay(&sop->so_replay);
+	atomic_set(&sop->so_count, 1);
+	return sop;
+}
+
+static void hash_openowner(struct nfs4_openowner *oo, struct nfs4_client *clp, unsigned int strhashval)
+{
+	lockdep_assert_held(&clp->cl_lock);
+
+	list_add(&oo->oo_owner.so_strhash,
+		 &clp->cl_ownerstr_hashtbl[strhashval]);
+	list_add(&oo->oo_perclient, &clp->cl_openowners);
+}
+
+static void nfs4_unhash_openowner(struct nfs4_stateowner *so)
+{
+	unhash_openowner_locked(openowner(so));
+}
+
+static void nfs4_free_openowner(struct nfs4_stateowner *so)
+{
+	struct nfs4_openowner *oo = openowner(so);
+
+	kmem_cache_free(openowner_slab, oo);
+}
+
+static const struct nfs4_stateowner_operations openowner_ops = {
+	.so_unhash =	nfs4_unhash_openowner,
+	.so_free =	nfs4_free_openowner,
+};
+
+static struct nfs4_ol_stateid *
+nfsd4_find_existing_open(struct nfs4_file *fp, struct nfsd4_open *open)
+{
+	struct nfs4_ol_stateid *local, *ret = NULL;
+	struct nfs4_openowner *oo = open->op_openowner;
+
+	lockdep_assert_held(&fp->fi_lock);
+
+	list_for_each_entry(local, &fp->fi_stateids, st_perfile) {
+		/* ignore lock owners */
+		if (local->st_stateowner->so_is_open_owner == 0)
+			continue;
+		if (local->st_stateowner != &oo->oo_owner)
+			continue;
+		if (local->st_stid.sc_type == NFS4_OPEN_STID) {
+			ret = local;
+			refcount_inc(&ret->st_stid.sc_count);
+			break;
+		}
+	}
+	return ret;
+}
+
+static __be32
+nfsd4_verify_open_stid(struct nfs4_stid *s)
+{
+	__be32 ret = nfs_ok;
+
+	switch (s->sc_type) {
+	default:
+		break;
+	case 0:
+	case NFS4_CLOSED_STID:
+	case NFS4_CLOSED_DELEG_STID:
+		ret = nfserr_bad_stateid;
+		break;
+	case NFS4_REVOKED_DELEG_STID:
+		ret = nfserr_deleg_revoked;
+	}
+	return ret;
+}
+
+/* Lock the stateid st_mutex, and deal with races with CLOSE */
+static __be32
+nfsd4_lock_ol_stateid(struct nfs4_ol_stateid *stp)
+{
+	__be32 ret;
+
+	mutex_lock_nested(&stp->st_mutex, LOCK_STATEID_MUTEX);
+	ret = nfsd4_verify_open_stid(&stp->st_stid);
+	if (ret != nfs_ok)
+		mutex_unlock(&stp->st_mutex);
+	return ret;
+}
+
+static struct nfs4_ol_stateid *
+nfsd4_find_and_lock_existing_open(struct nfs4_file *fp, struct nfsd4_open *open)
+{
+	struct nfs4_ol_stateid *stp;
+	for (;;) {
+		spin_lock(&fp->fi_lock);
+		stp = nfsd4_find_existing_open(fp, open);
+		spin_unlock(&fp->fi_lock);
+		if (!stp || nfsd4_lock_ol_stateid(stp) == nfs_ok)
+			break;
+		nfs4_put_stid(&stp->st_stid);
+	}
+	return stp;
+}
+
+static struct nfs4_openowner *
+alloc_init_open_stateowner(unsigned int strhashval, struct nfsd4_open *open,
+			   struct nfsd4_compound_state *cstate)
+{
+	struct nfs4_client *clp = cstate->clp;
+	struct nfs4_openowner *oo, *ret;
+
+	oo = alloc_stateowner(openowner_slab, &open->op_owner, clp);
+	if (!oo)
+		return NULL;
+	oo->oo_owner.so_ops = &openowner_ops;
+	oo->oo_owner.so_is_open_owner = 1;
+	oo->oo_owner.so_seqid = open->op_seqid;
+	oo->oo_flags = 0;
+	if (nfsd4_has_session(cstate))
+		oo->oo_flags |= NFS4_OO_CONFIRMED;
+	oo->oo_time = 0;
+	oo->oo_last_closed_stid = NULL;
+	INIT_LIST_HEAD(&oo->oo_close_lru);
+	spin_lock(&clp->cl_lock);
+	ret = find_openstateowner_str_locked(strhashval, open, clp);
+	if (ret == NULL) {
+		hash_openowner(oo, clp, strhashval);
+		ret = oo;
+	} else
+		nfs4_free_stateowner(&oo->oo_owner);
+
+	spin_unlock(&clp->cl_lock);
+	return ret;
+}
+
+static struct nfs4_ol_stateid *
+init_open_stateid(struct nfs4_file *fp, struct nfsd4_open *open)
+{
+
+	struct nfs4_openowner *oo = open->op_openowner;
+	struct nfs4_ol_stateid *retstp = NULL;
+	struct nfs4_ol_stateid *stp;
+
+	stp = open->op_stp;
+	/* We are moving these outside of the spinlocks to avoid the warnings */
+	mutex_init(&stp->st_mutex);
+	mutex_lock_nested(&stp->st_mutex, OPEN_STATEID_MUTEX);
+
+retry:
+	spin_lock(&oo->oo_owner.so_client->cl_lock);
+	spin_lock(&fp->fi_lock);
+
+	retstp = nfsd4_find_existing_open(fp, open);
+	if (retstp)
+		goto out_unlock;
+
+	open->op_stp = NULL;
+	refcount_inc(&stp->st_stid.sc_count);
+	stp->st_stid.sc_type = NFS4_OPEN_STID;
+	INIT_LIST_HEAD(&stp->st_locks);
+	stp->st_stateowner = nfs4_get_stateowner(&oo->oo_owner);
+	get_nfs4_file(fp);
+	stp->st_stid.sc_file = fp;
+	stp->st_access_bmap = 0;
+	stp->st_deny_bmap = 0;
+	stp->st_openstp = NULL;
+	list_add(&stp->st_perstateowner, &oo->oo_owner.so_stateids);
+	list_add(&stp->st_perfile, &fp->fi_stateids);
+
+out_unlock:
+	spin_unlock(&fp->fi_lock);
+	spin_unlock(&oo->oo_owner.so_client->cl_lock);
+	if (retstp) {
+		/* Handle races with CLOSE */
+		if (nfsd4_lock_ol_stateid(retstp) != nfs_ok) {
+			nfs4_put_stid(&retstp->st_stid);
+			goto retry;
+		}
+		/* To keep mutex tracking happy */
+		mutex_unlock(&stp->st_mutex);
+		stp = retstp;
+	}
+	return stp;
+}
+
+/*
+ * In the 4.0 case we need to keep the owners around a little while to handle
+ * CLOSE replay. We still do need to release any file access that is held by
+ * them before returning however.
+ */
+static void
+move_to_close_lru(struct nfs4_ol_stateid *s, struct net *net)
+{
+	struct nfs4_ol_stateid *last;
+	struct nfs4_openowner *oo = openowner(s->st_stateowner);
+	struct nfsd_net *nn = net_generic(s->st_stid.sc_client->net,
+						nfsd_net_id);
+
+	dprintk("NFSD: move_to_close_lru nfs4_openowner %p\n", oo);
+
+	/*
+	 * We know that we hold one reference via nfsd4_close, and another
+	 * "persistent" reference for the client. If the refcount is higher
+	 * than 2, then there are still calls in progress that are using this
+	 * stateid. We can't put the sc_file reference until they are finished.
+	 * Wait for the refcount to drop to 2. Since it has been unhashed,
+	 * there should be no danger of the refcount going back up again at
+	 * this point.
+	 */
+	wait_event(close_wq, refcount_read(&s->st_stid.sc_count) == 2);
+
+	release_all_access(s);
+	if (s->st_stid.sc_file) {
+		put_nfs4_file(s->st_stid.sc_file);
+		s->st_stid.sc_file = NULL;
+	}
+
+	spin_lock(&nn->client_lock);
+	last = oo->oo_last_closed_stid;
+	oo->oo_last_closed_stid = s;
+	list_move_tail(&oo->oo_close_lru, &nn->close_lru);
+	oo->oo_time = ktime_get_boottime_seconds();
+	spin_unlock(&nn->client_lock);
+	if (last)
+		nfs4_put_stid(&last->st_stid);
+}
+
+/* search file_hashtbl[] for file */
+static struct nfs4_file *
+find_file_locked(struct svc_fh *fh, unsigned int hashval)
+{
+	struct nfs4_file *fp;
+
+	hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,
+				lockdep_is_held(&state_lock)) {
+		if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) {
+			if (refcount_inc_not_zero(&fp->fi_ref))
+				return fp;
+		}
+	}
+	return NULL;
+}
+
+static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh,
+				     unsigned int hashval)
+{
+	struct nfs4_file *fp;
+	struct nfs4_file *ret = NULL;
+	bool alias_found = false;
+
+	spin_lock(&state_lock);
+	hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,
+				 lockdep_is_held(&state_lock)) {
+		if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) {
+			if (refcount_inc_not_zero(&fp->fi_ref))
+				ret = fp;
+		} else if (d_inode(fh->fh_dentry) == fp->fi_inode)
+			fp->fi_aliased = alias_found = true;
+	}
+	if (likely(ret == NULL)) {
+		nfsd4_init_file(fh, hashval, new);
+		new->fi_aliased = alias_found;
+		ret = new;
+	}
+	spin_unlock(&state_lock);
+	return ret;
+}
+
+static struct nfs4_file * find_file(struct svc_fh *fh)
+{
+	struct nfs4_file *fp;
+	unsigned int hashval = file_hashval(fh);
+
+	rcu_read_lock();
+	fp = find_file_locked(fh, hashval);
+	rcu_read_unlock();
+	return fp;
+}
+
+static struct nfs4_file *
+find_or_add_file(struct nfs4_file *new, struct svc_fh *fh)
+{
+	struct nfs4_file *fp;
+	unsigned int hashval = file_hashval(fh);
+
+	rcu_read_lock();
+	fp = find_file_locked(fh, hashval);
+	rcu_read_unlock();
+	if (fp)
+		return fp;
+
+	return insert_file(new, fh, hashval);
+}
+
+/*
+ * Called to check deny when READ with all zero stateid or
+ * WRITE with all zero or all one stateid
+ */
+static __be32
+nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type)
+{
+	struct nfs4_file *fp;
+	__be32 ret = nfs_ok;
+
+	fp = find_file(current_fh);
+	if (!fp)
+		return ret;
+	/* Check for conflicting share reservations */
+	spin_lock(&fp->fi_lock);
+	if (fp->fi_share_deny & deny_type)
+		ret = nfserr_locked;
+	spin_unlock(&fp->fi_lock);
+	put_nfs4_file(fp);
+	return ret;
+}
+
+static bool nfsd4_deleg_present(const struct inode *inode)
+{
+	struct file_lock_context *ctx = smp_load_acquire(&inode->i_flctx);
+
+	return ctx && !list_empty_careful(&ctx->flc_lease);
+}
+
+/**
+ * nfsd_wait_for_delegreturn - wait for delegations to be returned
+ * @rqstp: the RPC transaction being executed
+ * @inode: in-core inode of the file being waited for
+ *
+ * The timeout prevents deadlock if all nfsd threads happen to be
+ * tied up waiting for returning delegations.
+ *
+ * Return values:
+ *   %true: delegation was returned
+ *   %false: timed out waiting for delegreturn
+ */
+bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, struct inode *inode)
+{
+	long __maybe_unused timeo;
+
+	timeo = wait_var_event_timeout(inode, !nfsd4_deleg_present(inode),
+				       NFSD_DELEGRETURN_TIMEOUT);
+	trace_nfsd_delegret_wakeup(rqstp, inode, timeo);
+	return timeo > 0;
+}
+
+static void nfsd4_cb_recall_prepare(struct nfsd4_callback *cb)
+{
+	struct nfs4_delegation *dp = cb_to_delegation(cb);
+	struct nfsd_net *nn = net_generic(dp->dl_stid.sc_client->net,
+					  nfsd_net_id);
+
+	block_delegations(&dp->dl_stid.sc_file->fi_fhandle);
+
+	/*
+	 * We can't do this in nfsd_break_deleg_cb because it is
+	 * already holding inode->i_lock.
+	 *
+	 * If the dl_time != 0, then we know that it has already been
+	 * queued for a lease break. Don't queue it again.
+	 */
+	spin_lock(&state_lock);
+	if (delegation_hashed(dp) && dp->dl_time == 0) {
+		dp->dl_time = ktime_get_boottime_seconds();
+		list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru);
+	}
+	spin_unlock(&state_lock);
+}
+
+static int nfsd4_cb_recall_done(struct nfsd4_callback *cb,
+		struct rpc_task *task)
+{
+	struct nfs4_delegation *dp = cb_to_delegation(cb);
+
+	trace_nfsd_cb_recall_done(&dp->dl_stid.sc_stateid, task);
+
+	if (dp->dl_stid.sc_type == NFS4_CLOSED_DELEG_STID ||
+	    dp->dl_stid.sc_type == NFS4_REVOKED_DELEG_STID)
+	        return 1;
+
+	switch (task->tk_status) {
+	case 0:
+		return 1;
+	case -NFS4ERR_DELAY:
+		rpc_delay(task, 2 * HZ);
+		return 0;
+	case -EBADHANDLE:
+	case -NFS4ERR_BAD_STATEID:
+		/*
+		 * Race: client probably got cb_recall before open reply
+		 * granting delegation.
+		 */
+		if (dp->dl_retries--) {
+			rpc_delay(task, 2 * HZ);
+			return 0;
+		}
+		fallthrough;
+	default:
+		return 1;
+	}
+}
+
+static void nfsd4_cb_recall_release(struct nfsd4_callback *cb)
+{
+	struct nfs4_delegation *dp = cb_to_delegation(cb);
+
+	nfs4_put_stid(&dp->dl_stid);
+}
+
+static const struct nfsd4_callback_ops nfsd4_cb_recall_ops = {
+	.prepare	= nfsd4_cb_recall_prepare,
+	.done		= nfsd4_cb_recall_done,
+	.release	= nfsd4_cb_recall_release,
+};
+
+static void nfsd_break_one_deleg(struct nfs4_delegation *dp)
+{
+	/*
+	 * We're assuming the state code never drops its reference
+	 * without first removing the lease.  Since we're in this lease
+	 * callback (and since the lease code is serialized by the
+	 * flc_lock) we know the server hasn't removed the lease yet, and
+	 * we know it's safe to take a reference.
+	 */
+	refcount_inc(&dp->dl_stid.sc_count);
+	WARN_ON_ONCE(!nfsd4_run_cb(&dp->dl_recall));
+}
+
+/* Called from break_lease() with flc_lock held. */
+static bool
+nfsd_break_deleg_cb(struct file_lock *fl)
+{
+	struct nfs4_delegation *dp = (struct nfs4_delegation *)fl->fl_owner;
+	struct nfs4_file *fp = dp->dl_stid.sc_file;
+	struct nfs4_client *clp = dp->dl_stid.sc_client;
+	struct nfsd_net *nn;
+
+	trace_nfsd_cb_recall(&dp->dl_stid);
+
+	dp->dl_recalled = true;
+	atomic_inc(&clp->cl_delegs_in_recall);
+	if (try_to_expire_client(clp)) {
+		nn = net_generic(clp->net, nfsd_net_id);
+		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+	}
+
+	/*
+	 * We don't want the locks code to timeout the lease for us;
+	 * we'll remove it ourself if a delegation isn't returned
+	 * in time:
+	 */
+	fl->fl_break_time = 0;
+
+	spin_lock(&fp->fi_lock);
+	fp->fi_had_conflict = true;
+	nfsd_break_one_deleg(dp);
+	spin_unlock(&fp->fi_lock);
+	return false;
+}
+
+/**
+ * nfsd_breaker_owns_lease - Check if lease conflict was resolved
+ * @fl: Lock state to check
+ *
+ * Return values:
+ *   %true: Lease conflict was resolved
+ *   %false: Lease conflict was not resolved.
+ */
+static bool nfsd_breaker_owns_lease(struct file_lock *fl)
+{
+	struct nfs4_delegation *dl = fl->fl_owner;
+	struct svc_rqst *rqst;
+	struct nfs4_client *clp;
+
+	if (!i_am_nfsd())
+		return false;
+	rqst = kthread_data(current);
+	/* Note rq_prog == NFS_ACL_PROGRAM is also possible: */
+	if (rqst->rq_prog != NFS_PROGRAM || rqst->rq_vers < 4)
+		return false;
+	clp = *(rqst->rq_lease_breaker);
+	return dl->dl_stid.sc_client == clp;
+}
+
+static int
+nfsd_change_deleg_cb(struct file_lock *onlist, int arg,
+		     struct list_head *dispose)
+{
+	struct nfs4_delegation *dp = (struct nfs4_delegation *)onlist->fl_owner;
+	struct nfs4_client *clp = dp->dl_stid.sc_client;
+
+	if (arg & F_UNLCK) {
+		if (dp->dl_recalled)
+			atomic_dec(&clp->cl_delegs_in_recall);
+		return lease_modify(onlist, arg, dispose);
+	} else
+		return -EAGAIN;
+}
+
+static const struct lock_manager_operations nfsd_lease_mng_ops = {
+	.lm_breaker_owns_lease = nfsd_breaker_owns_lease,
+	.lm_break = nfsd_break_deleg_cb,
+	.lm_change = nfsd_change_deleg_cb,
+};
+
+static __be32 nfsd4_check_seqid(struct nfsd4_compound_state *cstate, struct nfs4_stateowner *so, u32 seqid)
+{
+	if (nfsd4_has_session(cstate))
+		return nfs_ok;
+	if (seqid == so->so_seqid - 1)
+		return nfserr_replay_me;
+	if (seqid == so->so_seqid)
+		return nfs_ok;
+	return nfserr_bad_seqid;
+}
+
+static struct nfs4_client *lookup_clientid(clientid_t *clid, bool sessions,
+						struct nfsd_net *nn)
+{
+	struct nfs4_client *found;
+
+	spin_lock(&nn->client_lock);
+	found = find_confirmed_client(clid, sessions, nn);
+	if (found)
+		atomic_inc(&found->cl_rpc_users);
+	spin_unlock(&nn->client_lock);
+	return found;
+}
+
+static __be32 set_client(clientid_t *clid,
+		struct nfsd4_compound_state *cstate,
+		struct nfsd_net *nn)
+{
+	if (cstate->clp) {
+		if (!same_clid(&cstate->clp->cl_clientid, clid))
+			return nfserr_stale_clientid;
+		return nfs_ok;
+	}
+	if (STALE_CLIENTID(clid, nn))
+		return nfserr_stale_clientid;
+	/*
+	 * We're in the 4.0 case (otherwise the SEQUENCE op would have
+	 * set cstate->clp), so session = false:
+	 */
+	cstate->clp = lookup_clientid(clid, false, nn);
+	if (!cstate->clp)
+		return nfserr_expired;
+	return nfs_ok;
+}
+
+__be32
+nfsd4_process_open1(struct nfsd4_compound_state *cstate,
+		    struct nfsd4_open *open, struct nfsd_net *nn)
+{
+	clientid_t *clientid = &open->op_clientid;
+	struct nfs4_client *clp = NULL;
+	unsigned int strhashval;
+	struct nfs4_openowner *oo = NULL;
+	__be32 status;
+
+	/*
+	 * In case we need it later, after we've already created the
+	 * file and don't want to risk a further failure:
+	 */
+	open->op_file = nfsd4_alloc_file();
+	if (open->op_file == NULL)
+		return nfserr_jukebox;
+
+	status = set_client(clientid, cstate, nn);
+	if (status)
+		return status;
+	clp = cstate->clp;
+
+	strhashval = ownerstr_hashval(&open->op_owner);
+	oo = find_openstateowner_str(strhashval, open, clp);
+	open->op_openowner = oo;
+	if (!oo) {
+		goto new_owner;
+	}
+	if (!(oo->oo_flags & NFS4_OO_CONFIRMED)) {
+		/* Replace unconfirmed owners without checking for replay. */
+		release_openowner(oo);
+		open->op_openowner = NULL;
+		goto new_owner;
+	}
+	status = nfsd4_check_seqid(cstate, &oo->oo_owner, open->op_seqid);
+	if (status)
+		return status;
+	goto alloc_stateid;
+new_owner:
+	oo = alloc_init_open_stateowner(strhashval, open, cstate);
+	if (oo == NULL)
+		return nfserr_jukebox;
+	open->op_openowner = oo;
+alloc_stateid:
+	open->op_stp = nfs4_alloc_open_stateid(clp);
+	if (!open->op_stp)
+		return nfserr_jukebox;
+
+	if (nfsd4_has_session(cstate) &&
+	    (cstate->current_fh.fh_export->ex_flags & NFSEXP_PNFS)) {
+		open->op_odstate = alloc_clnt_odstate(clp);
+		if (!open->op_odstate)
+			return nfserr_jukebox;
+	}
+
+	return nfs_ok;
+}
+
+static inline __be32
+nfs4_check_delegmode(struct nfs4_delegation *dp, int flags)
+{
+	if ((flags & WR_STATE) && (dp->dl_type == NFS4_OPEN_DELEGATE_READ))
+		return nfserr_openmode;
+	else
+		return nfs_ok;
+}
+
+static int share_access_to_flags(u32 share_access)
+{
+	return share_access == NFS4_SHARE_ACCESS_READ ? RD_STATE : WR_STATE;
+}
+
+static struct nfs4_delegation *find_deleg_stateid(struct nfs4_client *cl, stateid_t *s)
+{
+	struct nfs4_stid *ret;
+
+	ret = find_stateid_by_type(cl, s,
+				NFS4_DELEG_STID|NFS4_REVOKED_DELEG_STID);
+	if (!ret)
+		return NULL;
+	return delegstateid(ret);
+}
+
+static bool nfsd4_is_deleg_cur(struct nfsd4_open *open)
+{
+	return open->op_claim_type == NFS4_OPEN_CLAIM_DELEGATE_CUR ||
+	       open->op_claim_type == NFS4_OPEN_CLAIM_DELEG_CUR_FH;
+}
+
+static __be32
+nfs4_check_deleg(struct nfs4_client *cl, struct nfsd4_open *open,
+		struct nfs4_delegation **dp)
+{
+	int flags;
+	__be32 status = nfserr_bad_stateid;
+	struct nfs4_delegation *deleg;
+
+	deleg = find_deleg_stateid(cl, &open->op_delegate_stateid);
+	if (deleg == NULL)
+		goto out;
+	if (deleg->dl_stid.sc_type == NFS4_REVOKED_DELEG_STID) {
+		nfs4_put_stid(&deleg->dl_stid);
+		if (cl->cl_minorversion)
+			status = nfserr_deleg_revoked;
+		goto out;
+	}
+	flags = share_access_to_flags(open->op_share_access);
+	status = nfs4_check_delegmode(deleg, flags);
+	if (status) {
+		nfs4_put_stid(&deleg->dl_stid);
+		goto out;
+	}
+	*dp = deleg;
+out:
+	if (!nfsd4_is_deleg_cur(open))
+		return nfs_ok;
+	if (status)
+		return status;
+	open->op_openowner->oo_flags |= NFS4_OO_CONFIRMED;
+	return nfs_ok;
+}
+
+static inline int nfs4_access_to_access(u32 nfs4_access)
+{
+	int flags = 0;
+
+	if (nfs4_access & NFS4_SHARE_ACCESS_READ)
+		flags |= NFSD_MAY_READ;
+	if (nfs4_access & NFS4_SHARE_ACCESS_WRITE)
+		flags |= NFSD_MAY_WRITE;
+	return flags;
+}
+
+static inline __be32
+nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
+		struct nfsd4_open *open)
+{
+	struct iattr iattr = {
+		.ia_valid = ATTR_SIZE,
+		.ia_size = 0,
+	};
+	struct nfsd_attrs attrs = {
+		.na_iattr	= &iattr,
+	};
+	if (!open->op_truncate)
+		return 0;
+	if (!(open->op_share_access & NFS4_SHARE_ACCESS_WRITE))
+		return nfserr_inval;
+	return nfsd_setattr(rqstp, fh, &attrs, 0, (time64_t)0);
+}
+
+static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
+		struct svc_fh *cur_fh, struct nfs4_ol_stateid *stp,
+		struct nfsd4_open *open, bool new_stp)
+{
+	struct nfsd_file *nf = NULL;
+	__be32 status;
+	int oflag = nfs4_access_to_omode(open->op_share_access);
+	int access = nfs4_access_to_access(open->op_share_access);
+	unsigned char old_access_bmap, old_deny_bmap;
+
+	spin_lock(&fp->fi_lock);
+
+	/*
+	 * Are we trying to set a deny mode that would conflict with
+	 * current access?
+	 */
+	status = nfs4_file_check_deny(fp, open->op_share_deny);
+	if (status != nfs_ok) {
+		if (status != nfserr_share_denied) {
+			spin_unlock(&fp->fi_lock);
+			goto out;
+		}
+		if (nfs4_resolve_deny_conflicts_locked(fp, new_stp,
+				stp, open->op_share_deny, false))
+			status = nfserr_jukebox;
+		spin_unlock(&fp->fi_lock);
+		goto out;
+	}
+
+	/* set access to the file */
+	status = nfs4_file_get_access(fp, open->op_share_access);
+	if (status != nfs_ok) {
+		if (status != nfserr_share_denied) {
+			spin_unlock(&fp->fi_lock);
+			goto out;
+		}
+		if (nfs4_resolve_deny_conflicts_locked(fp, new_stp,
+				stp, open->op_share_access, true))
+			status = nfserr_jukebox;
+		spin_unlock(&fp->fi_lock);
+		goto out;
+	}
+
+	/* Set access bits in stateid */
+	old_access_bmap = stp->st_access_bmap;
+	set_access(open->op_share_access, stp);
+
+	/* Set new deny mask */
+	old_deny_bmap = stp->st_deny_bmap;
+	set_deny(open->op_share_deny, stp);
+	fp->fi_share_deny |= (open->op_share_deny & NFS4_SHARE_DENY_BOTH);
+
+	if (!fp->fi_fds[oflag]) {
+		spin_unlock(&fp->fi_lock);
+
+		status = nfsd_file_acquire_opened(rqstp, cur_fh, access,
+						  open->op_filp, &nf);
+		if (status != nfs_ok)
+			goto out_put_access;
+
+		spin_lock(&fp->fi_lock);
+		if (!fp->fi_fds[oflag]) {
+			fp->fi_fds[oflag] = nf;
+			nf = NULL;
+		}
+	}
+	spin_unlock(&fp->fi_lock);
+	if (nf)
+		nfsd_file_put(nf);
+
+	status = nfserrno(nfsd_open_break_lease(cur_fh->fh_dentry->d_inode,
+								access));
+	if (status)
+		goto out_put_access;
+
+	status = nfsd4_truncate(rqstp, cur_fh, open);
+	if (status)
+		goto out_put_access;
+out:
+	return status;
+out_put_access:
+	stp->st_access_bmap = old_access_bmap;
+	nfs4_file_put_access(fp, open->op_share_access);
+	reset_union_bmap_deny(bmap_to_share_mode(old_deny_bmap), stp);
+	goto out;
+}
+
+static __be32
+nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp,
+		struct svc_fh *cur_fh, struct nfs4_ol_stateid *stp,
+		struct nfsd4_open *open)
+{
+	__be32 status;
+	unsigned char old_deny_bmap = stp->st_deny_bmap;
+
+	if (!test_access(open->op_share_access, stp))
+		return nfs4_get_vfs_file(rqstp, fp, cur_fh, stp, open, false);
+
+	/* test and set deny mode */
+	spin_lock(&fp->fi_lock);
+	status = nfs4_file_check_deny(fp, open->op_share_deny);
+	switch (status) {
+	case nfs_ok:
+		set_deny(open->op_share_deny, stp);
+		fp->fi_share_deny |=
+			(open->op_share_deny & NFS4_SHARE_DENY_BOTH);
+		break;
+	case nfserr_share_denied:
+		if (nfs4_resolve_deny_conflicts_locked(fp, false,
+				stp, open->op_share_deny, false))
+			status = nfserr_jukebox;
+		break;
+	}
+	spin_unlock(&fp->fi_lock);
+
+	if (status != nfs_ok)
+		return status;
+
+	status = nfsd4_truncate(rqstp, cur_fh, open);
+	if (status != nfs_ok)
+		reset_union_bmap_deny(old_deny_bmap, stp);
+	return status;
+}
+
+/* Should we give out recallable state?: */
+static bool nfsd4_cb_channel_good(struct nfs4_client *clp)
+{
+	if (clp->cl_cb_state == NFSD4_CB_UP)
+		return true;
+	/*
+	 * In the sessions case, since we don't have to establish a
+	 * separate connection for callbacks, we assume it's OK
+	 * until we hear otherwise:
+	 */
+	return clp->cl_minorversion && clp->cl_cb_state == NFSD4_CB_UNKNOWN;
+}
+
+static struct file_lock *nfs4_alloc_init_lease(struct nfs4_delegation *dp,
+						int flag)
+{
+	struct file_lock *fl;
+
+	fl = locks_alloc_lock();
+	if (!fl)
+		return NULL;
+	fl->fl_lmops = &nfsd_lease_mng_ops;
+	fl->fl_flags = FL_DELEG;
+	fl->fl_type = flag == NFS4_OPEN_DELEGATE_READ? F_RDLCK: F_WRLCK;
+	fl->fl_end = OFFSET_MAX;
+	fl->fl_owner = (fl_owner_t)dp;
+	fl->fl_pid = current->tgid;
+	fl->fl_file = dp->dl_stid.sc_file->fi_deleg_file->nf_file;
+	return fl;
+}
+
+static int nfsd4_check_conflicting_opens(struct nfs4_client *clp,
+					 struct nfs4_file *fp)
+{
+	struct nfs4_ol_stateid *st;
+	struct file *f = fp->fi_deleg_file->nf_file;
+	struct inode *ino = locks_inode(f);
+	int writes;
+
+	writes = atomic_read(&ino->i_writecount);
+	if (!writes)
+		return 0;
+	/*
+	 * There could be multiple filehandles (hence multiple
+	 * nfs4_files) referencing this file, but that's not too
+	 * common; let's just give up in that case rather than
+	 * trying to go look up all the clients using that other
+	 * nfs4_file as well:
+	 */
+	if (fp->fi_aliased)
+		return -EAGAIN;
+	/*
+	 * If there's a close in progress, make sure that we see it
+	 * clear any fi_fds[] entries before we see it decrement
+	 * i_writecount:
+	 */
+	smp_mb__after_atomic();
+
+	if (fp->fi_fds[O_WRONLY])
+		writes--;
+	if (fp->fi_fds[O_RDWR])
+		writes--;
+	if (writes > 0)
+		return -EAGAIN; /* There may be non-NFSv4 writers */
+	/*
+	 * It's possible there are non-NFSv4 write opens in progress,
+	 * but if they haven't incremented i_writecount yet then they
+	 * also haven't called break lease yet; so, they'll break this
+	 * lease soon enough.  So, all that's left to check for is NFSv4
+	 * opens:
+	 */
+	spin_lock(&fp->fi_lock);
+	list_for_each_entry(st, &fp->fi_stateids, st_perfile) {
+		if (st->st_openstp == NULL /* it's an open */ &&
+		    access_permit_write(st) &&
+		    st->st_stid.sc_client != clp) {
+			spin_unlock(&fp->fi_lock);
+			return -EAGAIN;
+		}
+	}
+	spin_unlock(&fp->fi_lock);
+	/*
+	 * There's a small chance that we could be racing with another
+	 * NFSv4 open.  However, any open that hasn't added itself to
+	 * the fi_stateids list also hasn't called break_lease yet; so,
+	 * they'll break this lease soon enough.
+	 */
+	return 0;
+}
+
+/*
+ * It's possible that between opening the dentry and setting the delegation,
+ * that it has been renamed or unlinked. Redo the lookup to verify that this
+ * hasn't happened.
+ */
+static int
+nfsd4_verify_deleg_dentry(struct nfsd4_open *open, struct nfs4_file *fp,
+			  struct svc_fh *parent)
+{
+	struct svc_export *exp;
+	struct dentry *child;
+	__be32 err;
+
+	err = nfsd_lookup_dentry(open->op_rqstp, parent,
+				 open->op_fname, open->op_fnamelen,
+				 &exp, &child);
+
+	if (err)
+		return -EAGAIN;
+
+	exp_put(exp);
+	dput(child);
+	if (child != file_dentry(fp->fi_deleg_file->nf_file))
+		return -EAGAIN;
+
+	return 0;
+}
+
+/*
+ * We avoid breaking delegations held by a client due to its own activity, but
+ * clearing setuid/setgid bits on a write is an implicit activity and the client
+ * may not notice and continue using the old mode. Avoid giving out a delegation
+ * on setuid/setgid files when the client is requesting an open for write.
+ */
+static int
+nfsd4_verify_setuid_write(struct nfsd4_open *open, struct nfsd_file *nf)
+{
+	struct inode *inode = file_inode(nf->nf_file);
+
+	if ((open->op_share_access & NFS4_SHARE_ACCESS_WRITE) &&
+	    (inode->i_mode & (S_ISUID|S_ISGID)))
+		return -EAGAIN;
+	return 0;
+}
+
+static struct nfs4_delegation *
+nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
+		    struct svc_fh *parent)
+{
+	int status = 0;
+	struct nfs4_client *clp = stp->st_stid.sc_client;
+	struct nfs4_file *fp = stp->st_stid.sc_file;
+	struct nfs4_clnt_odstate *odstate = stp->st_clnt_odstate;
+	struct nfs4_delegation *dp;
+	struct nfsd_file *nf;
+	struct file_lock *fl;
+
+	/*
+	 * The fi_had_conflict and nfs_get_existing_delegation checks
+	 * here are just optimizations; we'll need to recheck them at
+	 * the end:
+	 */
+	if (fp->fi_had_conflict)
+		return ERR_PTR(-EAGAIN);
+
+	nf = find_readable_file(fp);
+	if (!nf) {
+		/*
+		 * We probably could attempt another open and get a read
+		 * delegation, but for now, don't bother until the
+		 * client actually sends us one.
+		 */
+		return ERR_PTR(-EAGAIN);
+	}
+	spin_lock(&state_lock);
+	spin_lock(&fp->fi_lock);
+	if (nfs4_delegation_exists(clp, fp))
+		status = -EAGAIN;
+	else if (nfsd4_verify_setuid_write(open, nf))
+		status = -EAGAIN;
+	else if (!fp->fi_deleg_file) {
+		fp->fi_deleg_file = nf;
+		/* increment early to prevent fi_deleg_file from being
+		 * cleared */
+		fp->fi_delegees = 1;
+		nf = NULL;
+	} else
+		fp->fi_delegees++;
+	spin_unlock(&fp->fi_lock);
+	spin_unlock(&state_lock);
+	if (nf)
+		nfsd_file_put(nf);
+	if (status)
+		return ERR_PTR(status);
+
+	status = -ENOMEM;
+	dp = alloc_init_deleg(clp, fp, odstate);
+	if (!dp)
+		goto out_delegees;
+
+	fl = nfs4_alloc_init_lease(dp, NFS4_OPEN_DELEGATE_READ);
+	if (!fl)
+		goto out_clnt_odstate;
+
+	status = vfs_setlease(fp->fi_deleg_file->nf_file, fl->fl_type, &fl, NULL);
+	if (fl)
+		locks_free_lock(fl);
+	if (status)
+		goto out_clnt_odstate;
+
+	if (parent) {
+		status = nfsd4_verify_deleg_dentry(open, fp, parent);
+		if (status)
+			goto out_unlock;
+	}
+
+	status = nfsd4_check_conflicting_opens(clp, fp);
+	if (status)
+		goto out_unlock;
+
+	/*
+	 * Now that the deleg is set, check again to ensure that nothing
+	 * raced in and changed the mode while we weren't lookng.
+	 */
+	status = nfsd4_verify_setuid_write(open, fp->fi_deleg_file);
+	if (status)
+		goto out_unlock;
+
+	spin_lock(&state_lock);
+	spin_lock(&fp->fi_lock);
+	if (fp->fi_had_conflict)
+		status = -EAGAIN;
+	else
+		status = hash_delegation_locked(dp, fp);
+	spin_unlock(&fp->fi_lock);
+	spin_unlock(&state_lock);
+
+	if (status)
+		goto out_unlock;
+
+	return dp;
+out_unlock:
+	vfs_setlease(fp->fi_deleg_file->nf_file, F_UNLCK, NULL, (void **)&dp);
+out_clnt_odstate:
+	put_clnt_odstate(dp->dl_clnt_odstate);
+	nfs4_put_stid(&dp->dl_stid);
+out_delegees:
+	put_deleg_file(fp);
+	return ERR_PTR(status);
+}
+
+static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
+{
+	open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+	if (status == -EAGAIN)
+		open->op_why_no_deleg = WND4_CONTENTION;
+	else {
+		open->op_why_no_deleg = WND4_RESOURCE;
+		switch (open->op_deleg_want) {
+		case NFS4_SHARE_WANT_READ_DELEG:
+		case NFS4_SHARE_WANT_WRITE_DELEG:
+		case NFS4_SHARE_WANT_ANY_DELEG:
+			break;
+		case NFS4_SHARE_WANT_CANCEL:
+			open->op_why_no_deleg = WND4_CANCELLED;
+			break;
+		case NFS4_SHARE_WANT_NO_DELEG:
+			WARN_ON_ONCE(1);
+		}
+	}
+}
+
+/*
+ * Attempt to hand out a delegation.
+ *
+ * Note we don't support write delegations, and won't until the vfs has
+ * proper support for them.
+ */
+static void
+nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
+		     struct svc_fh *currentfh)
+{
+	struct nfs4_delegation *dp;
+	struct nfs4_openowner *oo = openowner(stp->st_stateowner);
+	struct nfs4_client *clp = stp->st_stid.sc_client;
+	struct svc_fh *parent = NULL;
+	int cb_up;
+	int status = 0;
+
+	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
+	open->op_recall = 0;
+	switch (open->op_claim_type) {
+		case NFS4_OPEN_CLAIM_PREVIOUS:
+			if (!cb_up)
+				open->op_recall = 1;
+			if (open->op_delegate_type != NFS4_OPEN_DELEGATE_READ)
+				goto out_no_deleg;
+			break;
+		case NFS4_OPEN_CLAIM_NULL:
+			parent = currentfh;
+			fallthrough;
+		case NFS4_OPEN_CLAIM_FH:
+			/*
+			 * Let's not give out any delegations till everyone's
+			 * had the chance to reclaim theirs, *and* until
+			 * NLM locks have all been reclaimed:
+			 */
+			if (locks_in_grace(clp->net))
+				goto out_no_deleg;
+			if (!cb_up || !(oo->oo_flags & NFS4_OO_CONFIRMED))
+				goto out_no_deleg;
+			break;
+		default:
+			goto out_no_deleg;
+	}
+	dp = nfs4_set_delegation(open, stp, parent);
+	if (IS_ERR(dp))
+		goto out_no_deleg;
+
+	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
+
+	trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
+	open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
+	nfs4_put_stid(&dp->dl_stid);
+	return;
+out_no_deleg:
+	open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE;
+	if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS &&
+	    open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE) {
+		dprintk("NFSD: WARNING: refusing delegation reclaim\n");
+		open->op_recall = 1;
+	}
+
+	/* 4.1 client asking for a delegation? */
+	if (open->op_deleg_want)
+		nfsd4_open_deleg_none_ext(open, status);
+	return;
+}
+
+static void nfsd4_deleg_xgrade_none_ext(struct nfsd4_open *open,
+					struct nfs4_delegation *dp)
+{
+	if (open->op_deleg_want == NFS4_SHARE_WANT_READ_DELEG &&
+	    dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
+		open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+		open->op_why_no_deleg = WND4_NOT_SUPP_DOWNGRADE;
+	} else if (open->op_deleg_want == NFS4_SHARE_WANT_WRITE_DELEG &&
+		   dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
+		open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+		open->op_why_no_deleg = WND4_NOT_SUPP_UPGRADE;
+	}
+	/* Otherwise the client must be confused wanting a delegation
+	 * it already has, therefore we don't return
+	 * NFS4_OPEN_DELEGATE_NONE_EXT and reason.
+	 */
+}
+
+/**
+ * nfsd4_process_open2 - finish open processing
+ * @rqstp: the RPC transaction being executed
+ * @current_fh: NFSv4 COMPOUND's current filehandle
+ * @open: OPEN arguments
+ *
+ * If successful, (1) truncate the file if open->op_truncate was
+ * set, (2) set open->op_stateid, (3) set open->op_delegation.
+ *
+ * Returns %nfs_ok on success; otherwise an nfs4stat value in
+ * network byte order is returned.
+ */
+__be32
+nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
+{
+	struct nfsd4_compoundres *resp = rqstp->rq_resp;
+	struct nfs4_client *cl = open->op_openowner->oo_owner.so_client;
+	struct nfs4_file *fp = NULL;
+	struct nfs4_ol_stateid *stp = NULL;
+	struct nfs4_delegation *dp = NULL;
+	__be32 status;
+	bool new_stp = false;
+
+	/*
+	 * Lookup file; if found, lookup stateid and check open request,
+	 * and check for delegations in the process of being recalled.
+	 * If not found, create the nfs4_file struct
+	 */
+	fp = find_or_add_file(open->op_file, current_fh);
+	if (fp != open->op_file) {
+		status = nfs4_check_deleg(cl, open, &dp);
+		if (status)
+			goto out;
+		stp = nfsd4_find_and_lock_existing_open(fp, open);
+	} else {
+		open->op_file = NULL;
+		status = nfserr_bad_stateid;
+		if (nfsd4_is_deleg_cur(open))
+			goto out;
+	}
+
+	if (!stp) {
+		stp = init_open_stateid(fp, open);
+		if (!open->op_stp)
+			new_stp = true;
+	}
+
+	/*
+	 * OPEN the file, or upgrade an existing OPEN.
+	 * If truncate fails, the OPEN fails.
+	 *
+	 * stp is already locked.
+	 */
+	if (!new_stp) {
+		/* Stateid was found, this is an OPEN upgrade */
+		status = nfs4_upgrade_open(rqstp, fp, current_fh, stp, open);
+		if (status) {
+			mutex_unlock(&stp->st_mutex);
+			goto out;
+		}
+	} else {
+		status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open, true);
+		if (status) {
+			stp->st_stid.sc_type = NFS4_CLOSED_STID;
+			release_open_stateid(stp);
+			mutex_unlock(&stp->st_mutex);
+			goto out;
+		}
+
+		stp->st_clnt_odstate = find_or_hash_clnt_odstate(fp,
+							open->op_odstate);
+		if (stp->st_clnt_odstate == open->op_odstate)
+			open->op_odstate = NULL;
+	}
+
+	nfs4_inc_and_copy_stateid(&open->op_stateid, &stp->st_stid);
+	mutex_unlock(&stp->st_mutex);
+
+	if (nfsd4_has_session(&resp->cstate)) {
+		if (open->op_deleg_want & NFS4_SHARE_WANT_NO_DELEG) {
+			open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+			open->op_why_no_deleg = WND4_NOT_WANTED;
+			goto nodeleg;
+		}
+	}
+
+	/*
+	* Attempt to hand out a delegation. No error return, because the
+	* OPEN succeeds even if we fail.
+	*/
+	nfs4_open_delegation(open, stp, &resp->cstate.current_fh);
+nodeleg:
+	status = nfs_ok;
+	trace_nfsd_open(&stp->st_stid.sc_stateid);
+out:
+	/* 4.1 client trying to upgrade/downgrade delegation? */
+	if (open->op_delegate_type == NFS4_OPEN_DELEGATE_NONE && dp &&
+	    open->op_deleg_want)
+		nfsd4_deleg_xgrade_none_ext(open, dp);
+
+	if (fp)
+		put_nfs4_file(fp);
+	if (status == 0 && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
+		open->op_openowner->oo_flags |= NFS4_OO_CONFIRMED;
+	/*
+	* To finish the open response, we just need to set the rflags.
+	*/
+	open->op_rflags = NFS4_OPEN_RESULT_LOCKTYPE_POSIX;
+	if (nfsd4_has_session(&resp->cstate))
+		open->op_rflags |= NFS4_OPEN_RESULT_MAY_NOTIFY_LOCK;
+	else if (!(open->op_openowner->oo_flags & NFS4_OO_CONFIRMED))
+		open->op_rflags |= NFS4_OPEN_RESULT_CONFIRM;
+
+	if (dp)
+		nfs4_put_stid(&dp->dl_stid);
+	if (stp)
+		nfs4_put_stid(&stp->st_stid);
+
+	return status;
+}
+
+void nfsd4_cleanup_open_state(struct nfsd4_compound_state *cstate,
+			      struct nfsd4_open *open)
+{
+	if (open->op_openowner) {
+		struct nfs4_stateowner *so = &open->op_openowner->oo_owner;
+
+		nfsd4_cstate_assign_replay(cstate, so);
+		nfs4_put_stateowner(so);
+	}
+	if (open->op_file)
+		kmem_cache_free(file_slab, open->op_file);
+	if (open->op_stp)
+		nfs4_put_stid(&open->op_stp->st_stid);
+	if (open->op_odstate)
+		kmem_cache_free(odstate_slab, open->op_odstate);
+}
+
+__be32
+nfsd4_renew(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	    union nfsd4_op_u *u)
+{
+	clientid_t *clid = &u->renew;
+	struct nfs4_client *clp;
+	__be32 status;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	trace_nfsd_clid_renew(clid);
+	status = set_client(clid, cstate, nn);
+	if (status)
+		return status;
+	clp = cstate->clp;
+	if (!list_empty(&clp->cl_delegations)
+			&& clp->cl_cb_state != NFSD4_CB_UP)
+		return nfserr_cb_path_down;
+	return nfs_ok;
+}
+
+void
+nfsd4_end_grace(struct nfsd_net *nn)
+{
+	/* do nothing if grace period already ended */
+	if (nn->grace_ended)
+		return;
+
+	trace_nfsd_grace_complete(nn);
+	nn->grace_ended = true;
+	/*
+	 * If the server goes down again right now, an NFSv4
+	 * client will still be allowed to reclaim after it comes back up,
+	 * even if it hasn't yet had a chance to reclaim state this time.
+	 *
+	 */
+	nfsd4_record_grace_done(nn);
+	/*
+	 * At this point, NFSv4 clients can still reclaim.  But if the
+	 * server crashes, any that have not yet reclaimed will be out
+	 * of luck on the next boot.
+	 *
+	 * (NFSv4.1+ clients are considered to have reclaimed once they
+	 * call RECLAIM_COMPLETE.  NFSv4.0 clients are considered to
+	 * have reclaimed after their first OPEN.)
+	 */
+	locks_end_grace(&nn->nfsd4_manager);
+	/*
+	 * At this point, and once lockd and/or any other containers
+	 * exit their grace period, further reclaims will fail and
+	 * regular locking can resume.
+	 */
+}
+
+/*
+ * If we've waited a lease period but there are still clients trying to
+ * reclaim, wait a little longer to give them a chance to finish.
+ */
+static bool clients_still_reclaiming(struct nfsd_net *nn)
+{
+	time64_t double_grace_period_end = nn->boot_time +
+					   2 * nn->nfsd4_lease;
+
+	if (nn->track_reclaim_completes &&
+			atomic_read(&nn->nr_reclaim_complete) ==
+			nn->reclaim_str_hashtbl_size)
+		return false;
+	if (!nn->somebody_reclaimed)
+		return false;
+	nn->somebody_reclaimed = false;
+	/*
+	 * If we've given them *two* lease times to reclaim, and they're
+	 * still not done, give up:
+	 */
+	if (ktime_get_boottime_seconds() > double_grace_period_end)
+		return false;
+	return true;
+}
+
+struct laundry_time {
+	time64_t cutoff;
+	time64_t new_timeo;
+};
+
+static bool state_expired(struct laundry_time *lt, time64_t last_refresh)
+{
+	time64_t time_remaining;
+
+	if (last_refresh < lt->cutoff)
+		return true;
+	time_remaining = last_refresh - lt->cutoff;
+	lt->new_timeo = min(lt->new_timeo, time_remaining);
+	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 = NULL;
+	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 = NULL;
+	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
+
+/* Check if any lock belonging to this lockowner has any blockers */
+static bool
+nfs4_lockowner_has_blockers(struct nfs4_lockowner *lo)
+{
+	struct file_lock_context *ctx;
+	struct nfs4_ol_stateid *stp;
+	struct nfs4_file *nf;
+
+	list_for_each_entry(stp, &lo->lo_owner.so_stateids, st_perstateowner) {
+		nf = stp->st_stid.sc_file;
+		ctx = nf->fi_inode->i_flctx;
+		if (!ctx)
+			continue;
+		if (locks_owner_has_blockers(ctx, lo))
+			return true;
+	}
+	return false;
+}
+
+static bool
+nfs4_anylock_blockers(struct nfs4_client *clp)
+{
+	int i;
+	struct nfs4_stateowner *so;
+	struct nfs4_lockowner *lo;
+
+	if (atomic_read(&clp->cl_delegs_in_recall))
+		return true;
+	spin_lock(&clp->cl_lock);
+	for (i = 0; i < OWNER_HASH_SIZE; i++) {
+		list_for_each_entry(so, &clp->cl_ownerstr_hashtbl[i],
+				so_strhash) {
+			if (so->so_is_open_owner)
+				continue;
+			lo = lockowner(so);
+			if (nfs4_lockowner_has_blockers(lo)) {
+				spin_unlock(&clp->cl_lock);
+				return true;
+			}
+		}
+	}
+	spin_unlock(&clp->cl_lock);
+	return false;
+}
+
+static void
+nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist,
+				struct laundry_time *lt)
+{
+	unsigned int maxreap, reapcnt = 0;
+	struct list_head *pos, *next;
+	struct nfs4_client *clp;
+
+	maxreap = (atomic_read(&nn->nfs4_client_count) >= nn->nfs4_max_clients) ?
+			NFSD_CLIENT_MAX_TRIM_PER_RUN : 0;
+	INIT_LIST_HEAD(reaplist);
+	spin_lock(&nn->client_lock);
+	list_for_each_safe(pos, next, &nn->client_lru) {
+		clp = list_entry(pos, struct nfs4_client, cl_lru);
+		if (clp->cl_state == NFSD4_EXPIRABLE)
+			goto exp_client;
+		if (!state_expired(lt, clp->cl_time))
+			break;
+		if (!atomic_read(&clp->cl_rpc_users)) {
+			if (clp->cl_state == NFSD4_ACTIVE)
+				atomic_inc(&nn->nfsd_courtesy_clients);
+			clp->cl_state = NFSD4_COURTESY;
+		}
+		if (!client_has_state(clp))
+			goto exp_client;
+		if (!nfs4_anylock_blockers(clp))
+			if (reapcnt >= maxreap)
+				continue;
+exp_client:
+		if (!mark_client_expired_locked(clp)) {
+			list_add(&clp->cl_lru, reaplist);
+			reapcnt++;
+		}
+	}
+	spin_unlock(&nn->client_lock);
+}
+
+static void
+nfs4_get_courtesy_client_reaplist(struct nfsd_net *nn,
+				struct list_head *reaplist)
+{
+	unsigned int maxreap = 0, reapcnt = 0;
+	struct list_head *pos, *next;
+	struct nfs4_client *clp;
+
+	maxreap = NFSD_CLIENT_MAX_TRIM_PER_RUN;
+	INIT_LIST_HEAD(reaplist);
+
+	spin_lock(&nn->client_lock);
+	list_for_each_safe(pos, next, &nn->client_lru) {
+		clp = list_entry(pos, struct nfs4_client, cl_lru);
+		if (clp->cl_state == NFSD4_ACTIVE)
+			break;
+		if (reapcnt >= maxreap)
+			break;
+		if (!mark_client_expired_locked(clp)) {
+			list_add(&clp->cl_lru, reaplist);
+			reapcnt++;
+		}
+	}
+	spin_unlock(&nn->client_lock);
+}
+
+static void
+nfs4_process_client_reaplist(struct list_head *reaplist)
+{
+	struct list_head *pos, *next;
+	struct nfs4_client *clp;
+
+	list_for_each_safe(pos, next, reaplist) {
+		clp = list_entry(pos, struct nfs4_client, cl_lru);
+		trace_nfsd_clid_purged(&clp->cl_clientid);
+		list_del_init(&clp->cl_lru);
+		expire_client(clp);
+	}
+}
+
+static time64_t
+nfs4_laundromat(struct nfsd_net *nn)
+{
+	struct nfs4_openowner *oo;
+	struct nfs4_delegation *dp;
+	struct nfs4_ol_stateid *stp;
+	struct nfsd4_blocked_lock *nbl;
+	struct list_head *pos, *next, reaplist;
+	struct laundry_time lt = {
+		.cutoff = ktime_get_boottime_seconds() - nn->nfsd4_lease,
+		.new_timeo = nn->nfsd4_lease
+	};
+	struct nfs4_cpntf_state *cps;
+	copy_stateid_t *cps_t;
+	int i;
+
+	if (clients_still_reclaiming(nn)) {
+		lt.new_timeo = 0;
+		goto out;
+	}
+	nfsd4_end_grace(nn);
+
+	spin_lock(&nn->s2s_cp_lock);
+	idr_for_each_entry(&nn->s2s_cp_stateids, cps_t, i) {
+		cps = container_of(cps_t, struct nfs4_cpntf_state, cp_stateid);
+		if (cps->cp_stateid.cs_type == NFS4_COPYNOTIFY_STID &&
+				state_expired(&lt, cps->cpntf_time))
+			_free_cpntf_state_locked(nn, cps);
+	}
+	spin_unlock(&nn->s2s_cp_lock);
+	nfs4_get_client_reaplist(nn, &reaplist, &lt);
+	nfs4_process_client_reaplist(&reaplist);
+
+	spin_lock(&state_lock);
+	list_for_each_safe(pos, next, &nn->del_recall_lru) {
+		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
+		if (!state_expired(&lt, dp->dl_time))
+			break;
+		WARN_ON(!unhash_delegation_locked(dp));
+		list_add(&dp->dl_recall_lru, &reaplist);
+	}
+	spin_unlock(&state_lock);
+	while (!list_empty(&reaplist)) {
+		dp = list_first_entry(&reaplist, struct nfs4_delegation,
+					dl_recall_lru);
+		list_del_init(&dp->dl_recall_lru);
+		revoke_delegation(dp);
+	}
+
+	spin_lock(&nn->client_lock);
+	while (!list_empty(&nn->close_lru)) {
+		oo = list_first_entry(&nn->close_lru, struct nfs4_openowner,
+					oo_close_lru);
+		if (!state_expired(&lt, oo->oo_time))
+			break;
+		list_del_init(&oo->oo_close_lru);
+		stp = oo->oo_last_closed_stid;
+		oo->oo_last_closed_stid = NULL;
+		spin_unlock(&nn->client_lock);
+		nfs4_put_stid(&stp->st_stid);
+		spin_lock(&nn->client_lock);
+	}
+	spin_unlock(&nn->client_lock);
+
+	/*
+	 * It's possible for a client to try and acquire an already held lock
+	 * that is being held for a long time, and then lose interest in it.
+	 * So, we clean out any un-revisited request after a lease period
+	 * under the assumption that the client is no longer interested.
+	 *
+	 * RFC5661, sec. 9.6 states that the client must not rely on getting
+	 * notifications and must continue to poll for locks, even when the
+	 * server supports them. Thus this shouldn't lead to clients blocking
+	 * indefinitely once the lock does become free.
+	 */
+	BUG_ON(!list_empty(&reaplist));
+	spin_lock(&nn->blocked_locks_lock);
+	while (!list_empty(&nn->blocked_locks_lru)) {
+		nbl = list_first_entry(&nn->blocked_locks_lru,
+					struct nfsd4_blocked_lock, nbl_lru);
+		if (!state_expired(&lt, nbl->nbl_time))
+			break;
+		list_move(&nbl->nbl_lru, &reaplist);
+		list_del_init(&nbl->nbl_list);
+	}
+	spin_unlock(&nn->blocked_locks_lock);
+
+	while (!list_empty(&reaplist)) {
+		nbl = list_first_entry(&reaplist,
+					struct nfsd4_blocked_lock, nbl_lru);
+		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);
+}
+
+static void laundromat_main(struct work_struct *);
+
+static void
+laundromat_main(struct work_struct *laundry)
+{
+	time64_t t;
+	struct delayed_work *dwork = to_delayed_work(laundry);
+	struct nfsd_net *nn = container_of(dwork, struct nfsd_net,
+					   laundromat_work);
+
+	t = nfs4_laundromat(nn);
+	queue_delayed_work(laundry_wq, &nn->laundromat_work, t*HZ);
+}
+
+static void
+courtesy_client_reaper(struct work_struct *reaper)
+{
+	struct list_head reaplist;
+	struct delayed_work *dwork = to_delayed_work(reaper);
+	struct nfsd_net *nn = container_of(dwork, struct nfsd_net,
+					nfsd_shrinker_work);
+
+	nfs4_get_courtesy_client_reaplist(nn, &reaplist);
+	nfs4_process_client_reaplist(&reaplist);
+}
+
+static inline __be32 nfs4_check_fh(struct svc_fh *fhp, struct nfs4_stid *stp)
+{
+	if (!fh_match(&fhp->fh_handle, &stp->sc_file->fi_fhandle))
+		return nfserr_bad_stateid;
+	return nfs_ok;
+}
+
+static
+__be32 nfs4_check_openmode(struct nfs4_ol_stateid *stp, int flags)
+{
+        __be32 status = nfserr_openmode;
+
+	/* For lock stateid's, we test the parent open, not the lock: */
+	if (stp->st_openstp)
+		stp = stp->st_openstp;
+	if ((flags & WR_STATE) && !access_permit_write(stp))
+                goto out;
+	if ((flags & RD_STATE) && !access_permit_read(stp))
+                goto out;
+	status = nfs_ok;
+out:
+	return status;
+}
+
+static inline __be32
+check_special_stateids(struct net *net, svc_fh *current_fh, stateid_t *stateid, int flags)
+{
+	if (ONE_STATEID(stateid) && (flags & RD_STATE))
+		return nfs_ok;
+	else if (opens_in_grace(net)) {
+		/* Answer in remaining cases depends on existence of
+		 * conflicting state; so we must wait out the grace period. */
+		return nfserr_grace;
+	} else if (flags & WR_STATE)
+		return nfs4_share_conflict(current_fh,
+				NFS4_SHARE_DENY_WRITE);
+	else /* (flags & RD_STATE) && ZERO_STATEID(stateid) */
+		return nfs4_share_conflict(current_fh,
+				NFS4_SHARE_DENY_READ);
+}
+
+static __be32 check_stateid_generation(stateid_t *in, stateid_t *ref, bool has_session)
+{
+	/*
+	 * When sessions are used the stateid generation number is ignored
+	 * when it is zero.
+	 */
+	if (has_session && in->si_generation == 0)
+		return nfs_ok;
+
+	if (in->si_generation == ref->si_generation)
+		return nfs_ok;
+
+	/* If the client sends us a stateid from the future, it's buggy: */
+	if (nfsd4_stateid_generation_after(in, ref))
+		return nfserr_bad_stateid;
+	/*
+	 * However, we could see a stateid from the past, even from a
+	 * non-buggy client.  For example, if the client sends a lock
+	 * while some IO is outstanding, the lock may bump si_generation
+	 * while the IO is still in flight.  The client could avoid that
+	 * situation by waiting for responses on all the IO requests,
+	 * but better performance may result in retrying IO that
+	 * receives an old_stateid error if requests are rarely
+	 * reordered in flight:
+	 */
+	return nfserr_old_stateid;
+}
+
+static __be32 nfsd4_stid_check_stateid_generation(stateid_t *in, struct nfs4_stid *s, bool has_session)
+{
+	__be32 ret;
+
+	spin_lock(&s->sc_lock);
+	ret = nfsd4_verify_open_stid(s);
+	if (ret == nfs_ok)
+		ret = check_stateid_generation(in, &s->sc_stateid, has_session);
+	spin_unlock(&s->sc_lock);
+	return ret;
+}
+
+static __be32 nfsd4_check_openowner_confirmed(struct nfs4_ol_stateid *ols)
+{
+	if (ols->st_stateowner->so_is_open_owner &&
+	    !(openowner(ols->st_stateowner)->oo_flags & NFS4_OO_CONFIRMED))
+		return nfserr_bad_stateid;
+	return nfs_ok;
+}
+
+static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
+{
+	struct nfs4_stid *s;
+	__be32 status = nfserr_bad_stateid;
+
+	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
+		CLOSE_STATEID(stateid))
+		return status;
+	spin_lock(&cl->cl_lock);
+	s = find_stateid_locked(cl, stateid);
+	if (!s)
+		goto out_unlock;
+	status = nfsd4_stid_check_stateid_generation(stateid, s, 1);
+	if (status)
+		goto out_unlock;
+	switch (s->sc_type) {
+	case NFS4_DELEG_STID:
+		status = nfs_ok;
+		break;
+	case NFS4_REVOKED_DELEG_STID:
+		status = nfserr_deleg_revoked;
+		break;
+	case NFS4_OPEN_STID:
+	case NFS4_LOCK_STID:
+		status = nfsd4_check_openowner_confirmed(openlockstateid(s));
+		break;
+	default:
+		printk("unknown stateid type %x\n", s->sc_type);
+		fallthrough;
+	case NFS4_CLOSED_STID:
+	case NFS4_CLOSED_DELEG_STID:
+		status = nfserr_bad_stateid;
+	}
+out_unlock:
+	spin_unlock(&cl->cl_lock);
+	return status;
+}
+
+__be32
+nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
+		     stateid_t *stateid, unsigned char typemask,
+		     struct nfs4_stid **s, struct nfsd_net *nn)
+{
+	__be32 status;
+	struct nfs4_stid *stid;
+	bool return_revoked = false;
+
+	/*
+	 *  only return revoked delegations if explicitly asked.
+	 *  otherwise we report revoked or bad_stateid status.
+	 */
+	if (typemask & NFS4_REVOKED_DELEG_STID)
+		return_revoked = true;
+	else if (typemask & NFS4_DELEG_STID)
+		typemask |= NFS4_REVOKED_DELEG_STID;
+
+	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
+		CLOSE_STATEID(stateid))
+		return nfserr_bad_stateid;
+	status = set_client(&stateid->si_opaque.so_clid, cstate, nn);
+	if (status == nfserr_stale_clientid) {
+		if (cstate->session)
+			return nfserr_bad_stateid;
+		return nfserr_stale_stateid;
+	}
+	if (status)
+		return status;
+	stid = find_stateid_by_type(cstate->clp, stateid, typemask);
+	if (!stid)
+		return nfserr_bad_stateid;
+	if ((stid->sc_type == NFS4_REVOKED_DELEG_STID) && !return_revoked) {
+		nfs4_put_stid(stid);
+		if (cstate->minorversion)
+			return nfserr_deleg_revoked;
+		return nfserr_bad_stateid;
+	}
+	*s = stid;
+	return nfs_ok;
+}
+
+static struct nfsd_file *
+nfs4_find_file(struct nfs4_stid *s, int flags)
+{
+	if (!s)
+		return NULL;
+
+	switch (s->sc_type) {
+	case NFS4_DELEG_STID:
+		if (WARN_ON_ONCE(!s->sc_file->fi_deleg_file))
+			return NULL;
+		return nfsd_file_get(s->sc_file->fi_deleg_file);
+	case NFS4_OPEN_STID:
+	case NFS4_LOCK_STID:
+		if (flags & RD_STATE)
+			return find_readable_file(s->sc_file);
+		else
+			return find_writeable_file(s->sc_file);
+	}
+
+	return NULL;
+}
+
+static __be32
+nfs4_check_olstateid(struct nfs4_ol_stateid *ols, int flags)
+{
+	__be32 status;
+
+	status = nfsd4_check_openowner_confirmed(ols);
+	if (status)
+		return status;
+	return nfs4_check_openmode(ols, flags);
+}
+
+static __be32
+nfs4_check_file(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfs4_stid *s,
+		struct nfsd_file **nfp, int flags)
+{
+	int acc = (flags & RD_STATE) ? NFSD_MAY_READ : NFSD_MAY_WRITE;
+	struct nfsd_file *nf;
+	__be32 status;
+
+	nf = nfs4_find_file(s, flags);
+	if (nf) {
+		status = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
+				acc | NFSD_MAY_OWNER_OVERRIDE);
+		if (status) {
+			nfsd_file_put(nf);
+			goto out;
+		}
+	} else {
+		status = nfsd_file_acquire(rqstp, fhp, acc, &nf);
+		if (status)
+			return status;
+	}
+	*nfp = nf;
+out:
+	return status;
+}
+static void
+_free_cpntf_state_locked(struct nfsd_net *nn, struct nfs4_cpntf_state *cps)
+{
+	WARN_ON_ONCE(cps->cp_stateid.cs_type != NFS4_COPYNOTIFY_STID);
+	if (!refcount_dec_and_test(&cps->cp_stateid.cs_count))
+		return;
+	list_del(&cps->cp_list);
+	idr_remove(&nn->s2s_cp_stateids,
+		   cps->cp_stateid.cs_stid.si_opaque.so_id);
+	kfree(cps);
+}
+/*
+ * A READ from an inter server to server COPY will have a
+ * copy stateid. Look up the copy notify stateid from the
+ * idr structure and take a reference on it.
+ */
+__be32 manage_cpntf_state(struct nfsd_net *nn, stateid_t *st,
+			  struct nfs4_client *clp,
+			  struct nfs4_cpntf_state **cps)
+{
+	copy_stateid_t *cps_t;
+	struct nfs4_cpntf_state *state = NULL;
+
+	if (st->si_opaque.so_clid.cl_id != nn->s2s_cp_cl_id)
+		return nfserr_bad_stateid;
+	spin_lock(&nn->s2s_cp_lock);
+	cps_t = idr_find(&nn->s2s_cp_stateids, st->si_opaque.so_id);
+	if (cps_t) {
+		state = container_of(cps_t, struct nfs4_cpntf_state,
+				     cp_stateid);
+		if (state->cp_stateid.cs_type != NFS4_COPYNOTIFY_STID) {
+			state = NULL;
+			goto unlock;
+		}
+		if (!clp)
+			refcount_inc(&state->cp_stateid.cs_count);
+		else
+			_free_cpntf_state_locked(nn, state);
+	}
+unlock:
+	spin_unlock(&nn->s2s_cp_lock);
+	if (!state)
+		return nfserr_bad_stateid;
+	if (!clp && state)
+		*cps = state;
+	return 0;
+}
+
+static __be32 find_cpntf_state(struct nfsd_net *nn, stateid_t *st,
+			       struct nfs4_stid **stid)
+{
+	__be32 status;
+	struct nfs4_cpntf_state *cps = NULL;
+	struct nfs4_client *found;
+
+	status = manage_cpntf_state(nn, st, NULL, &cps);
+	if (status)
+		return status;
+
+	cps->cpntf_time = ktime_get_boottime_seconds();
+
+	status = nfserr_expired;
+	found = lookup_clientid(&cps->cp_p_clid, true, nn);
+	if (!found)
+		goto out;
+
+	*stid = find_stateid_by_type(found, &cps->cp_p_stateid,
+			NFS4_DELEG_STID|NFS4_OPEN_STID|NFS4_LOCK_STID);
+	if (*stid)
+		status = nfs_ok;
+	else
+		status = nfserr_bad_stateid;
+
+	put_client_renew(found);
+out:
+	nfs4_put_cpntf_state(nn, cps);
+	return status;
+}
+
+void nfs4_put_cpntf_state(struct nfsd_net *nn, struct nfs4_cpntf_state *cps)
+{
+	spin_lock(&nn->s2s_cp_lock);
+	_free_cpntf_state_locked(nn, cps);
+	spin_unlock(&nn->s2s_cp_lock);
+}
+
+/*
+ * Checks for stateid operations
+ */
+__be32
+nfs4_preprocess_stateid_op(struct svc_rqst *rqstp,
+		struct nfsd4_compound_state *cstate, struct svc_fh *fhp,
+		stateid_t *stateid, int flags, struct nfsd_file **nfp,
+		struct nfs4_stid **cstid)
+{
+	struct net *net = SVC_NET(rqstp);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct nfs4_stid *s = NULL;
+	__be32 status;
+
+	if (nfp)
+		*nfp = NULL;
+
+	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid)) {
+		if (cstid)
+			status = nfserr_bad_stateid;
+		else
+			status = check_special_stateids(net, fhp, stateid,
+									flags);
+		goto done;
+	}
+
+	status = nfsd4_lookup_stateid(cstate, stateid,
+				NFS4_DELEG_STID|NFS4_OPEN_STID|NFS4_LOCK_STID,
+				&s, nn);
+	if (status == nfserr_bad_stateid)
+		status = find_cpntf_state(nn, stateid, &s);
+	if (status)
+		return status;
+	status = nfsd4_stid_check_stateid_generation(stateid, s,
+			nfsd4_has_session(cstate));
+	if (status)
+		goto out;
+
+	switch (s->sc_type) {
+	case NFS4_DELEG_STID:
+		status = nfs4_check_delegmode(delegstateid(s), flags);
+		break;
+	case NFS4_OPEN_STID:
+	case NFS4_LOCK_STID:
+		status = nfs4_check_olstateid(openlockstateid(s), flags);
+		break;
+	default:
+		status = nfserr_bad_stateid;
+		break;
+	}
+	if (status)
+		goto out;
+	status = nfs4_check_fh(fhp, s);
+
+done:
+	if (status == nfs_ok && nfp)
+		status = nfs4_check_file(rqstp, fhp, s, nfp, flags);
+out:
+	if (s) {
+		if (!status && cstid)
+			*cstid = s;
+		else
+			nfs4_put_stid(s);
+	}
+	return status;
+}
+
+/*
+ * Test if the stateid is valid
+ */
+__be32
+nfsd4_test_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		   union nfsd4_op_u *u)
+{
+	struct nfsd4_test_stateid *test_stateid = &u->test_stateid;
+	struct nfsd4_test_stateid_id *stateid;
+	struct nfs4_client *cl = cstate->clp;
+
+	list_for_each_entry(stateid, &test_stateid->ts_stateid_list, ts_id_list)
+		stateid->ts_id_status =
+			nfsd4_validate_stateid(cl, &stateid->ts_id_stateid);
+
+	return nfs_ok;
+}
+
+static __be32
+nfsd4_free_lock_stateid(stateid_t *stateid, struct nfs4_stid *s)
+{
+	struct nfs4_ol_stateid *stp = openlockstateid(s);
+	__be32 ret;
+
+	ret = nfsd4_lock_ol_stateid(stp);
+	if (ret)
+		goto out_put_stid;
+
+	ret = check_stateid_generation(stateid, &s->sc_stateid, 1);
+	if (ret)
+		goto out;
+
+	ret = nfserr_locks_held;
+	if (check_for_locks(stp->st_stid.sc_file,
+			    lockowner(stp->st_stateowner)))
+		goto out;
+
+	release_lock_stateid(stp);
+	ret = nfs_ok;
+
+out:
+	mutex_unlock(&stp->st_mutex);
+out_put_stid:
+	nfs4_put_stid(s);
+	return ret;
+}
+
+__be32
+nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		   union nfsd4_op_u *u)
+{
+	struct nfsd4_free_stateid *free_stateid = &u->free_stateid;
+	stateid_t *stateid = &free_stateid->fr_stateid;
+	struct nfs4_stid *s;
+	struct nfs4_delegation *dp;
+	struct nfs4_client *cl = cstate->clp;
+	__be32 ret = nfserr_bad_stateid;
+
+	spin_lock(&cl->cl_lock);
+	s = find_stateid_locked(cl, stateid);
+	if (!s)
+		goto out_unlock;
+	spin_lock(&s->sc_lock);
+	switch (s->sc_type) {
+	case NFS4_DELEG_STID:
+		ret = nfserr_locks_held;
+		break;
+	case NFS4_OPEN_STID:
+		ret = check_stateid_generation(stateid, &s->sc_stateid, 1);
+		if (ret)
+			break;
+		ret = nfserr_locks_held;
+		break;
+	case NFS4_LOCK_STID:
+		spin_unlock(&s->sc_lock);
+		refcount_inc(&s->sc_count);
+		spin_unlock(&cl->cl_lock);
+		ret = nfsd4_free_lock_stateid(stateid, s);
+		goto out;
+	case NFS4_REVOKED_DELEG_STID:
+		spin_unlock(&s->sc_lock);
+		dp = delegstateid(s);
+		list_del_init(&dp->dl_recall_lru);
+		spin_unlock(&cl->cl_lock);
+		nfs4_put_stid(s);
+		ret = nfs_ok;
+		goto out;
+	/* Default falls through and returns nfserr_bad_stateid */
+	}
+	spin_unlock(&s->sc_lock);
+out_unlock:
+	spin_unlock(&cl->cl_lock);
+out:
+	return ret;
+}
+
+static inline int
+setlkflg (int type)
+{
+	return (type == NFS4_READW_LT || type == NFS4_READ_LT) ?
+		RD_STATE : WR_STATE;
+}
+
+static __be32 nfs4_seqid_op_checks(struct nfsd4_compound_state *cstate, stateid_t *stateid, u32 seqid, struct nfs4_ol_stateid *stp)
+{
+	struct svc_fh *current_fh = &cstate->current_fh;
+	struct nfs4_stateowner *sop = stp->st_stateowner;
+	__be32 status;
+
+	status = nfsd4_check_seqid(cstate, sop, seqid);
+	if (status)
+		return status;
+	status = nfsd4_lock_ol_stateid(stp);
+	if (status != nfs_ok)
+		return status;
+	status = check_stateid_generation(stateid, &stp->st_stid.sc_stateid, nfsd4_has_session(cstate));
+	if (status == nfs_ok)
+		status = nfs4_check_fh(current_fh, &stp->st_stid);
+	if (status != nfs_ok)
+		mutex_unlock(&stp->st_mutex);
+	return status;
+}
+
+/* 
+ * Checks for sequence id mutating operations. 
+ */
+static __be32
+nfs4_preprocess_seqid_op(struct nfsd4_compound_state *cstate, u32 seqid,
+			 stateid_t *stateid, char typemask,
+			 struct nfs4_ol_stateid **stpp,
+			 struct nfsd_net *nn)
+{
+	__be32 status;
+	struct nfs4_stid *s;
+	struct nfs4_ol_stateid *stp = NULL;
+
+	trace_nfsd_preprocess(seqid, stateid);
+
+	*stpp = NULL;
+	status = nfsd4_lookup_stateid(cstate, stateid, typemask, &s, nn);
+	if (status)
+		return status;
+	stp = openlockstateid(s);
+	nfsd4_cstate_assign_replay(cstate, stp->st_stateowner);
+
+	status = nfs4_seqid_op_checks(cstate, stateid, seqid, stp);
+	if (!status)
+		*stpp = stp;
+	else
+		nfs4_put_stid(&stp->st_stid);
+	return status;
+}
+
+static __be32 nfs4_preprocess_confirmed_seqid_op(struct nfsd4_compound_state *cstate, u32 seqid,
+						 stateid_t *stateid, struct nfs4_ol_stateid **stpp, struct nfsd_net *nn)
+{
+	__be32 status;
+	struct nfs4_openowner *oo;
+	struct nfs4_ol_stateid *stp;
+
+	status = nfs4_preprocess_seqid_op(cstate, seqid, stateid,
+						NFS4_OPEN_STID, &stp, nn);
+	if (status)
+		return status;
+	oo = openowner(stp->st_stateowner);
+	if (!(oo->oo_flags & NFS4_OO_CONFIRMED)) {
+		mutex_unlock(&stp->st_mutex);
+		nfs4_put_stid(&stp->st_stid);
+		return nfserr_bad_stateid;
+	}
+	*stpp = stp;
+	return nfs_ok;
+}
+
+__be32
+nfsd4_open_confirm(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		   union nfsd4_op_u *u)
+{
+	struct nfsd4_open_confirm *oc = &u->open_confirm;
+	__be32 status;
+	struct nfs4_openowner *oo;
+	struct nfs4_ol_stateid *stp;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	dprintk("NFSD: nfsd4_open_confirm on file %pd\n",
+			cstate->current_fh.fh_dentry);
+
+	status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0);
+	if (status)
+		return status;
+
+	status = nfs4_preprocess_seqid_op(cstate,
+					oc->oc_seqid, &oc->oc_req_stateid,
+					NFS4_OPEN_STID, &stp, nn);
+	if (status)
+		goto out;
+	oo = openowner(stp->st_stateowner);
+	status = nfserr_bad_stateid;
+	if (oo->oo_flags & NFS4_OO_CONFIRMED) {
+		mutex_unlock(&stp->st_mutex);
+		goto put_stateid;
+	}
+	oo->oo_flags |= NFS4_OO_CONFIRMED;
+	nfs4_inc_and_copy_stateid(&oc->oc_resp_stateid, &stp->st_stid);
+	mutex_unlock(&stp->st_mutex);
+	trace_nfsd_open_confirm(oc->oc_seqid, &stp->st_stid.sc_stateid);
+	nfsd4_client_record_create(oo->oo_owner.so_client);
+	status = nfs_ok;
+put_stateid:
+	nfs4_put_stid(&stp->st_stid);
+out:
+	nfsd4_bump_seqid(cstate, status);
+	return status;
+}
+
+static inline void nfs4_stateid_downgrade_bit(struct nfs4_ol_stateid *stp, u32 access)
+{
+	if (!test_access(access, stp))
+		return;
+	nfs4_file_put_access(stp->st_stid.sc_file, access);
+	clear_access(access, stp);
+}
+
+static inline void nfs4_stateid_downgrade(struct nfs4_ol_stateid *stp, u32 to_access)
+{
+	switch (to_access) {
+	case NFS4_SHARE_ACCESS_READ:
+		nfs4_stateid_downgrade_bit(stp, NFS4_SHARE_ACCESS_WRITE);
+		nfs4_stateid_downgrade_bit(stp, NFS4_SHARE_ACCESS_BOTH);
+		break;
+	case NFS4_SHARE_ACCESS_WRITE:
+		nfs4_stateid_downgrade_bit(stp, NFS4_SHARE_ACCESS_READ);
+		nfs4_stateid_downgrade_bit(stp, NFS4_SHARE_ACCESS_BOTH);
+		break;
+	case NFS4_SHARE_ACCESS_BOTH:
+		break;
+	default:
+		WARN_ON_ONCE(1);
+	}
+}
+
+__be32
+nfsd4_open_downgrade(struct svc_rqst *rqstp,
+		     struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
+{
+	struct nfsd4_open_downgrade *od = &u->open_downgrade;
+	__be32 status;
+	struct nfs4_ol_stateid *stp;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	dprintk("NFSD: nfsd4_open_downgrade on file %pd\n", 
+			cstate->current_fh.fh_dentry);
+
+	/* We don't yet support WANT bits: */
+	if (od->od_deleg_want)
+		dprintk("NFSD: %s: od_deleg_want=0x%x ignored\n", __func__,
+			od->od_deleg_want);
+
+	status = nfs4_preprocess_confirmed_seqid_op(cstate, od->od_seqid,
+					&od->od_stateid, &stp, nn);
+	if (status)
+		goto out; 
+	status = nfserr_inval;
+	if (!test_access(od->od_share_access, stp)) {
+		dprintk("NFSD: access not a subset of current bitmap: 0x%hhx, input access=%08x\n",
+			stp->st_access_bmap, od->od_share_access);
+		goto put_stateid;
+	}
+	if (!test_deny(od->od_share_deny, stp)) {
+		dprintk("NFSD: deny not a subset of current bitmap: 0x%hhx, input deny=%08x\n",
+			stp->st_deny_bmap, od->od_share_deny);
+		goto put_stateid;
+	}
+	nfs4_stateid_downgrade(stp, od->od_share_access);
+	reset_union_bmap_deny(od->od_share_deny, stp);
+	nfs4_inc_and_copy_stateid(&od->od_stateid, &stp->st_stid);
+	status = nfs_ok;
+put_stateid:
+	mutex_unlock(&stp->st_mutex);
+	nfs4_put_stid(&stp->st_stid);
+out:
+	nfsd4_bump_seqid(cstate, status);
+	return status;
+}
+
+static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
+{
+	struct nfs4_client *clp = s->st_stid.sc_client;
+	bool unhashed;
+	LIST_HEAD(reaplist);
+	struct nfs4_ol_stateid *stp;
+
+	spin_lock(&clp->cl_lock);
+	unhashed = unhash_open_stateid(s, &reaplist);
+
+	if (clp->cl_minorversion) {
+		if (unhashed)
+			put_ol_stateid_locked(s, &reaplist);
+		spin_unlock(&clp->cl_lock);
+		list_for_each_entry(stp, &reaplist, st_locks)
+			nfs4_free_cpntf_statelist(clp->net, &stp->st_stid);
+		free_ol_stateid_reaplist(&reaplist);
+	} else {
+		spin_unlock(&clp->cl_lock);
+		free_ol_stateid_reaplist(&reaplist);
+		if (unhashed)
+			move_to_close_lru(s, clp->net);
+	}
+}
+
+/*
+ * nfs4_unlock_state() called after encode
+ */
+__be32
+nfsd4_close(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	struct nfsd4_close *close = &u->close;
+	__be32 status;
+	struct nfs4_ol_stateid *stp;
+	struct net *net = SVC_NET(rqstp);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	dprintk("NFSD: nfsd4_close on file %pd\n", 
+			cstate->current_fh.fh_dentry);
+
+	status = nfs4_preprocess_seqid_op(cstate, close->cl_seqid,
+					&close->cl_stateid,
+					NFS4_OPEN_STID|NFS4_CLOSED_STID,
+					&stp, nn);
+	nfsd4_bump_seqid(cstate, status);
+	if (status)
+		goto out; 
+
+	stp->st_stid.sc_type = NFS4_CLOSED_STID;
+
+	/*
+	 * Technically we don't _really_ have to increment or copy it, since
+	 * it should just be gone after this operation and we clobber the
+	 * copied value below, but we continue to do so here just to ensure
+	 * that racing ops see that there was a state change.
+	 */
+	nfs4_inc_and_copy_stateid(&close->cl_stateid, &stp->st_stid);
+
+	nfsd4_close_open_stateid(stp);
+	mutex_unlock(&stp->st_mutex);
+
+	/* v4.1+ suggests that we send a special stateid in here, since the
+	 * clients should just ignore this anyway. Since this is not useful
+	 * for v4.0 clients either, we set it to the special close_stateid
+	 * universally.
+	 *
+	 * See RFC5661 section 18.2.4, and RFC7530 section 16.2.5
+	 */
+	memcpy(&close->cl_stateid, &close_stateid, sizeof(close->cl_stateid));
+
+	/* put reference from nfs4_preprocess_seqid_op */
+	nfs4_put_stid(&stp->st_stid);
+out:
+	return status;
+}
+
+__be32
+nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		  union nfsd4_op_u *u)
+{
+	struct nfsd4_delegreturn *dr = &u->delegreturn;
+	struct nfs4_delegation *dp;
+	stateid_t *stateid = &dr->dr_stateid;
+	struct nfs4_stid *s;
+	__be32 status;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	if ((status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0)))
+		return status;
+
+	status = nfsd4_lookup_stateid(cstate, stateid, NFS4_DELEG_STID, &s, nn);
+	if (status)
+		goto out;
+	dp = delegstateid(s);
+	status = nfsd4_stid_check_stateid_generation(stateid, &dp->dl_stid, nfsd4_has_session(cstate));
+	if (status)
+		goto put_stateid;
+
+	wake_up_var(d_inode(cstate->current_fh.fh_dentry));
+	destroy_delegation(dp);
+put_stateid:
+	nfs4_put_stid(&dp->dl_stid);
+out:
+	return status;
+}
+
+/* last octet in a range */
+static inline u64
+last_byte_offset(u64 start, u64 len)
+{
+	u64 end;
+
+	WARN_ON_ONCE(!len);
+	end = start + len;
+	return end > start ? end - 1: NFS4_MAX_UINT64;
+}
+
+/*
+ * TODO: Linux file offsets are _signed_ 64-bit quantities, which means that
+ * we can't properly handle lock requests that go beyond the (2^63 - 1)-th
+ * byte, because of sign extension problems.  Since NFSv4 calls for 64-bit
+ * locking, this prevents us from being completely protocol-compliant.  The
+ * real solution to this problem is to start using unsigned file offsets in
+ * the VFS, but this is a very deep change!
+ */
+static inline void
+nfs4_transform_lock_offset(struct file_lock *lock)
+{
+	if (lock->fl_start < 0)
+		lock->fl_start = OFFSET_MAX;
+	if (lock->fl_end < 0)
+		lock->fl_end = OFFSET_MAX;
+}
+
+static fl_owner_t
+nfsd4_lm_get_owner(fl_owner_t owner)
+{
+	struct nfs4_lockowner *lo = (struct nfs4_lockowner *)owner;
+
+	nfs4_get_stateowner(&lo->lo_owner);
+	return owner;
+}
+
+static void
+nfsd4_lm_put_owner(fl_owner_t owner)
+{
+	struct nfs4_lockowner *lo = (struct nfs4_lockowner *)owner;
+
+	if (lo)
+		nfs4_put_stateowner(&lo->lo_owner);
+}
+
+/* return pointer to struct nfs4_client if client is expirable */
+static bool
+nfsd4_lm_lock_expirable(struct file_lock *cfl)
+{
+	struct nfs4_lockowner *lo = (struct nfs4_lockowner *)cfl->fl_owner;
+	struct nfs4_client *clp = lo->lo_owner.so_client;
+	struct nfsd_net *nn;
+
+	if (try_to_expire_client(clp)) {
+		nn = net_generic(clp->net, nfsd_net_id);
+		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+		return true;
+	}
+	return false;
+}
+
+/* schedule laundromat to run immediately and wait for it to complete */
+static void
+nfsd4_lm_expire_lock(void)
+{
+	flush_workqueue(laundry_wq);
+}
+
+static void
+nfsd4_lm_notify(struct file_lock *fl)
+{
+	struct nfs4_lockowner		*lo = (struct nfs4_lockowner *)fl->fl_owner;
+	struct net			*net = lo->lo_owner.so_client->net;
+	struct nfsd_net			*nn = net_generic(net, nfsd_net_id);
+	struct nfsd4_blocked_lock	*nbl = container_of(fl,
+						struct nfsd4_blocked_lock, nbl_lock);
+	bool queue = false;
+
+	/* An empty list means that something else is going to be using it */
+	spin_lock(&nn->blocked_locks_lock);
+	if (!list_empty(&nbl->nbl_list)) {
+		list_del_init(&nbl->nbl_list);
+		list_del_init(&nbl->nbl_lru);
+		queue = true;
+	}
+	spin_unlock(&nn->blocked_locks_lock);
+
+	if (queue) {
+		trace_nfsd_cb_notify_lock(lo, nbl);
+		nfsd4_run_cb(&nbl->nbl_cb);
+	}
+}
+
+static const struct lock_manager_operations nfsd_posix_mng_ops  = {
+	.lm_mod_owner = THIS_MODULE,
+	.lm_notify = nfsd4_lm_notify,
+	.lm_get_owner = nfsd4_lm_get_owner,
+	.lm_put_owner = nfsd4_lm_put_owner,
+	.lm_lock_expirable = nfsd4_lm_lock_expirable,
+	.lm_expire_lock = nfsd4_lm_expire_lock,
+};
+
+static inline void
+nfs4_set_lock_denied(struct file_lock *fl, struct nfsd4_lock_denied *deny)
+{
+	struct nfs4_lockowner *lo;
+
+	if (fl->fl_lmops == &nfsd_posix_mng_ops) {
+		lo = (struct nfs4_lockowner *) fl->fl_owner;
+		xdr_netobj_dup(&deny->ld_owner, &lo->lo_owner.so_owner,
+						GFP_KERNEL);
+		if (!deny->ld_owner.data)
+			/* We just don't care that much */
+			goto nevermind;
+		deny->ld_clientid = lo->lo_owner.so_client->cl_clientid;
+	} else {
+nevermind:
+		deny->ld_owner.len = 0;
+		deny->ld_owner.data = NULL;
+		deny->ld_clientid.cl_boot = 0;
+		deny->ld_clientid.cl_id = 0;
+	}
+	deny->ld_start = fl->fl_start;
+	deny->ld_length = NFS4_MAX_UINT64;
+	if (fl->fl_end != NFS4_MAX_UINT64)
+		deny->ld_length = fl->fl_end - fl->fl_start + 1;        
+	deny->ld_type = NFS4_READ_LT;
+	if (fl->fl_type != F_RDLCK)
+		deny->ld_type = NFS4_WRITE_LT;
+}
+
+static struct nfs4_lockowner *
+find_lockowner_str_locked(struct nfs4_client *clp, struct xdr_netobj *owner)
+{
+	unsigned int strhashval = ownerstr_hashval(owner);
+	struct nfs4_stateowner *so;
+
+	lockdep_assert_held(&clp->cl_lock);
+
+	list_for_each_entry(so, &clp->cl_ownerstr_hashtbl[strhashval],
+			    so_strhash) {
+		if (so->so_is_open_owner)
+			continue;
+		if (same_owner_str(so, owner))
+			return lockowner(nfs4_get_stateowner(so));
+	}
+	return NULL;
+}
+
+static struct nfs4_lockowner *
+find_lockowner_str(struct nfs4_client *clp, struct xdr_netobj *owner)
+{
+	struct nfs4_lockowner *lo;
+
+	spin_lock(&clp->cl_lock);
+	lo = find_lockowner_str_locked(clp, owner);
+	spin_unlock(&clp->cl_lock);
+	return lo;
+}
+
+static void nfs4_unhash_lockowner(struct nfs4_stateowner *sop)
+{
+	unhash_lockowner_locked(lockowner(sop));
+}
+
+static void nfs4_free_lockowner(struct nfs4_stateowner *sop)
+{
+	struct nfs4_lockowner *lo = lockowner(sop);
+
+	kmem_cache_free(lockowner_slab, lo);
+}
+
+static const struct nfs4_stateowner_operations lockowner_ops = {
+	.so_unhash =	nfs4_unhash_lockowner,
+	.so_free =	nfs4_free_lockowner,
+};
+
+/*
+ * Alloc a lock owner structure.
+ * Called in nfsd4_lock - therefore, OPEN and OPEN_CONFIRM (if needed) has 
+ * occurred. 
+ *
+ * strhashval = ownerstr_hashval
+ */
+static struct nfs4_lockowner *
+alloc_init_lock_stateowner(unsigned int strhashval, struct nfs4_client *clp,
+			   struct nfs4_ol_stateid *open_stp,
+			   struct nfsd4_lock *lock)
+{
+	struct nfs4_lockowner *lo, *ret;
+
+	lo = alloc_stateowner(lockowner_slab, &lock->lk_new_owner, clp);
+	if (!lo)
+		return NULL;
+	INIT_LIST_HEAD(&lo->lo_blocked);
+	INIT_LIST_HEAD(&lo->lo_owner.so_stateids);
+	lo->lo_owner.so_is_open_owner = 0;
+	lo->lo_owner.so_seqid = lock->lk_new_lock_seqid;
+	lo->lo_owner.so_ops = &lockowner_ops;
+	spin_lock(&clp->cl_lock);
+	ret = find_lockowner_str_locked(clp, &lock->lk_new_owner);
+	if (ret == NULL) {
+		list_add(&lo->lo_owner.so_strhash,
+			 &clp->cl_ownerstr_hashtbl[strhashval]);
+		ret = lo;
+	} else
+		nfs4_free_stateowner(&lo->lo_owner);
+
+	spin_unlock(&clp->cl_lock);
+	return ret;
+}
+
+static struct nfs4_ol_stateid *
+find_lock_stateid(const struct nfs4_lockowner *lo,
+		  const struct nfs4_ol_stateid *ost)
+{
+	struct nfs4_ol_stateid *lst;
+
+	lockdep_assert_held(&ost->st_stid.sc_client->cl_lock);
+
+	/* If ost is not hashed, ost->st_locks will not be valid */
+	if (!nfs4_ol_stateid_unhashed(ost))
+		list_for_each_entry(lst, &ost->st_locks, st_locks) {
+			if (lst->st_stateowner == &lo->lo_owner) {
+				refcount_inc(&lst->st_stid.sc_count);
+				return lst;
+			}
+		}
+	return NULL;
+}
+
+static struct nfs4_ol_stateid *
+init_lock_stateid(struct nfs4_ol_stateid *stp, struct nfs4_lockowner *lo,
+		  struct nfs4_file *fp, struct inode *inode,
+		  struct nfs4_ol_stateid *open_stp)
+{
+	struct nfs4_client *clp = lo->lo_owner.so_client;
+	struct nfs4_ol_stateid *retstp;
+
+	mutex_init(&stp->st_mutex);
+	mutex_lock_nested(&stp->st_mutex, OPEN_STATEID_MUTEX);
+retry:
+	spin_lock(&clp->cl_lock);
+	if (nfs4_ol_stateid_unhashed(open_stp))
+		goto out_close;
+	retstp = find_lock_stateid(lo, open_stp);
+	if (retstp)
+		goto out_found;
+	refcount_inc(&stp->st_stid.sc_count);
+	stp->st_stid.sc_type = NFS4_LOCK_STID;
+	stp->st_stateowner = nfs4_get_stateowner(&lo->lo_owner);
+	get_nfs4_file(fp);
+	stp->st_stid.sc_file = fp;
+	stp->st_access_bmap = 0;
+	stp->st_deny_bmap = open_stp->st_deny_bmap;
+	stp->st_openstp = open_stp;
+	spin_lock(&fp->fi_lock);
+	list_add(&stp->st_locks, &open_stp->st_locks);
+	list_add(&stp->st_perstateowner, &lo->lo_owner.so_stateids);
+	list_add(&stp->st_perfile, &fp->fi_stateids);
+	spin_unlock(&fp->fi_lock);
+	spin_unlock(&clp->cl_lock);
+	return stp;
+out_found:
+	spin_unlock(&clp->cl_lock);
+	if (nfsd4_lock_ol_stateid(retstp) != nfs_ok) {
+		nfs4_put_stid(&retstp->st_stid);
+		goto retry;
+	}
+	/* To keep mutex tracking happy */
+	mutex_unlock(&stp->st_mutex);
+	return retstp;
+out_close:
+	spin_unlock(&clp->cl_lock);
+	mutex_unlock(&stp->st_mutex);
+	return NULL;
+}
+
+static struct nfs4_ol_stateid *
+find_or_create_lock_stateid(struct nfs4_lockowner *lo, struct nfs4_file *fi,
+			    struct inode *inode, struct nfs4_ol_stateid *ost,
+			    bool *new)
+{
+	struct nfs4_stid *ns = NULL;
+	struct nfs4_ol_stateid *lst;
+	struct nfs4_openowner *oo = openowner(ost->st_stateowner);
+	struct nfs4_client *clp = oo->oo_owner.so_client;
+
+	*new = false;
+	spin_lock(&clp->cl_lock);
+	lst = find_lock_stateid(lo, ost);
+	spin_unlock(&clp->cl_lock);
+	if (lst != NULL) {
+		if (nfsd4_lock_ol_stateid(lst) == nfs_ok)
+			goto out;
+		nfs4_put_stid(&lst->st_stid);
+	}
+	ns = nfs4_alloc_stid(clp, stateid_slab, nfs4_free_lock_stateid);
+	if (ns == NULL)
+		return NULL;
+
+	lst = init_lock_stateid(openlockstateid(ns), lo, fi, inode, ost);
+	if (lst == openlockstateid(ns))
+		*new = true;
+	else
+		nfs4_put_stid(ns);
+out:
+	return lst;
+}
+
+static int
+check_lock_length(u64 offset, u64 length)
+{
+	return ((length == 0) || ((length != NFS4_MAX_UINT64) &&
+		(length > ~offset)));
+}
+
+static void get_lock_access(struct nfs4_ol_stateid *lock_stp, u32 access)
+{
+	struct nfs4_file *fp = lock_stp->st_stid.sc_file;
+
+	lockdep_assert_held(&fp->fi_lock);
+
+	if (test_access(access, lock_stp))
+		return;
+	__nfs4_file_get_access(fp, access);
+	set_access(access, lock_stp);
+}
+
+static __be32
+lookup_or_create_lock_state(struct nfsd4_compound_state *cstate,
+			    struct nfs4_ol_stateid *ost,
+			    struct nfsd4_lock *lock,
+			    struct nfs4_ol_stateid **plst, bool *new)
+{
+	__be32 status;
+	struct nfs4_file *fi = ost->st_stid.sc_file;
+	struct nfs4_openowner *oo = openowner(ost->st_stateowner);
+	struct nfs4_client *cl = oo->oo_owner.so_client;
+	struct inode *inode = d_inode(cstate->current_fh.fh_dentry);
+	struct nfs4_lockowner *lo;
+	struct nfs4_ol_stateid *lst;
+	unsigned int strhashval;
+
+	lo = find_lockowner_str(cl, &lock->lk_new_owner);
+	if (!lo) {
+		strhashval = ownerstr_hashval(&lock->lk_new_owner);
+		lo = alloc_init_lock_stateowner(strhashval, cl, ost, lock);
+		if (lo == NULL)
+			return nfserr_jukebox;
+	} else {
+		/* with an existing lockowner, seqids must be the same */
+		status = nfserr_bad_seqid;
+		if (!cstate->minorversion &&
+		    lock->lk_new_lock_seqid != lo->lo_owner.so_seqid)
+			goto out;
+	}
+
+	lst = find_or_create_lock_stateid(lo, fi, inode, ost, new);
+	if (lst == NULL) {
+		status = nfserr_jukebox;
+		goto out;
+	}
+
+	status = nfs_ok;
+	*plst = lst;
+out:
+	nfs4_put_stateowner(&lo->lo_owner);
+	return status;
+}
+
+/*
+ *  LOCK operation 
+ */
+__be32
+nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	   union nfsd4_op_u *u)
+{
+	struct nfsd4_lock *lock = &u->lock;
+	struct nfs4_openowner *open_sop = NULL;
+	struct nfs4_lockowner *lock_sop = NULL;
+	struct nfs4_ol_stateid *lock_stp = NULL;
+	struct nfs4_ol_stateid *open_stp = NULL;
+	struct nfs4_file *fp;
+	struct nfsd_file *nf = NULL;
+	struct nfsd4_blocked_lock *nbl = NULL;
+	struct file_lock *file_lock = NULL;
+	struct file_lock *conflock = NULL;
+	__be32 status = 0;
+	int lkflg;
+	int err;
+	bool new = false;
+	unsigned char fl_type;
+	unsigned int fl_flags = FL_POSIX;
+	struct net *net = SVC_NET(rqstp);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	dprintk("NFSD: nfsd4_lock: start=%Ld length=%Ld\n",
+		(long long) lock->lk_offset,
+		(long long) lock->lk_length);
+
+	if (check_lock_length(lock->lk_offset, lock->lk_length))
+		 return nfserr_inval;
+
+	if ((status = fh_verify(rqstp, &cstate->current_fh,
+				S_IFREG, NFSD_MAY_LOCK))) {
+		dprintk("NFSD: nfsd4_lock: permission denied!\n");
+		return status;
+	}
+
+	if (lock->lk_is_new) {
+		if (nfsd4_has_session(cstate))
+			/* See rfc 5661 18.10.3: given clientid is ignored: */
+			memcpy(&lock->lk_new_clientid,
+				&cstate->clp->cl_clientid,
+				sizeof(clientid_t));
+
+		/* validate and update open stateid and open seqid */
+		status = nfs4_preprocess_confirmed_seqid_op(cstate,
+				        lock->lk_new_open_seqid,
+		                        &lock->lk_new_open_stateid,
+					&open_stp, nn);
+		if (status)
+			goto out;
+		mutex_unlock(&open_stp->st_mutex);
+		open_sop = openowner(open_stp->st_stateowner);
+		status = nfserr_bad_stateid;
+		if (!same_clid(&open_sop->oo_owner.so_client->cl_clientid,
+						&lock->lk_new_clientid))
+			goto out;
+		status = lookup_or_create_lock_state(cstate, open_stp, lock,
+							&lock_stp, &new);
+	} else {
+		status = nfs4_preprocess_seqid_op(cstate,
+				       lock->lk_old_lock_seqid,
+				       &lock->lk_old_lock_stateid,
+				       NFS4_LOCK_STID, &lock_stp, nn);
+	}
+	if (status)
+		goto out;
+	lock_sop = lockowner(lock_stp->st_stateowner);
+
+	lkflg = setlkflg(lock->lk_type);
+	status = nfs4_check_openmode(lock_stp, lkflg);
+	if (status)
+		goto out;
+
+	status = nfserr_grace;
+	if (locks_in_grace(net) && !lock->lk_reclaim)
+		goto out;
+	status = nfserr_no_grace;
+	if (!locks_in_grace(net) && lock->lk_reclaim)
+		goto out;
+
+	if (lock->lk_reclaim)
+		fl_flags |= FL_RECLAIM;
+
+	fp = lock_stp->st_stid.sc_file;
+	switch (lock->lk_type) {
+		case NFS4_READW_LT:
+			if (nfsd4_has_session(cstate))
+				fl_flags |= FL_SLEEP;
+			fallthrough;
+		case NFS4_READ_LT:
+			spin_lock(&fp->fi_lock);
+			nf = find_readable_file_locked(fp);
+			if (nf)
+				get_lock_access(lock_stp, NFS4_SHARE_ACCESS_READ);
+			spin_unlock(&fp->fi_lock);
+			fl_type = F_RDLCK;
+			break;
+		case NFS4_WRITEW_LT:
+			if (nfsd4_has_session(cstate))
+				fl_flags |= FL_SLEEP;
+			fallthrough;
+		case NFS4_WRITE_LT:
+			spin_lock(&fp->fi_lock);
+			nf = find_writeable_file_locked(fp);
+			if (nf)
+				get_lock_access(lock_stp, NFS4_SHARE_ACCESS_WRITE);
+			spin_unlock(&fp->fi_lock);
+			fl_type = F_WRLCK;
+			break;
+		default:
+			status = nfserr_inval;
+		goto out;
+	}
+
+	if (!nf) {
+		status = nfserr_openmode;
+		goto out;
+	}
+
+	/*
+	 * Most filesystems with their own ->lock operations will block
+	 * the nfsd thread waiting to acquire the lock.  That leads to
+	 * deadlocks (we don't want every nfsd thread tied up waiting
+	 * for file locks), so don't attempt blocking lock notifications
+	 * on those filesystems:
+	 */
+	if (nf->nf_file->f_op->lock)
+		fl_flags &= ~FL_SLEEP;
+
+	nbl = find_or_allocate_block(lock_sop, &fp->fi_fhandle, nn);
+	if (!nbl) {
+		dprintk("NFSD: %s: unable to allocate block!\n", __func__);
+		status = nfserr_jukebox;
+		goto out;
+	}
+
+	file_lock = &nbl->nbl_lock;
+	file_lock->fl_type = fl_type;
+	file_lock->fl_owner = (fl_owner_t)lockowner(nfs4_get_stateowner(&lock_sop->lo_owner));
+	file_lock->fl_pid = current->tgid;
+	file_lock->fl_file = nf->nf_file;
+	file_lock->fl_flags = fl_flags;
+	file_lock->fl_lmops = &nfsd_posix_mng_ops;
+	file_lock->fl_start = lock->lk_offset;
+	file_lock->fl_end = last_byte_offset(lock->lk_offset, lock->lk_length);
+	nfs4_transform_lock_offset(file_lock);
+
+	conflock = locks_alloc_lock();
+	if (!conflock) {
+		dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
+		status = nfserr_jukebox;
+		goto out;
+	}
+
+	if (fl_flags & FL_SLEEP) {
+		nbl->nbl_time = ktime_get_boottime_seconds();
+		spin_lock(&nn->blocked_locks_lock);
+		list_add_tail(&nbl->nbl_list, &lock_sop->lo_blocked);
+		list_add_tail(&nbl->nbl_lru, &nn->blocked_locks_lru);
+		kref_get(&nbl->nbl_kref);
+		spin_unlock(&nn->blocked_locks_lock);
+	}
+
+	err = vfs_lock_file(nf->nf_file, F_SETLK, file_lock, conflock);
+	switch (err) {
+	case 0: /* success! */
+		nfs4_inc_and_copy_stateid(&lock->lk_resp_stateid, &lock_stp->st_stid);
+		status = 0;
+		if (lock->lk_reclaim)
+			nn->somebody_reclaimed = true;
+		break;
+	case FILE_LOCK_DEFERRED:
+		kref_put(&nbl->nbl_kref, free_nbl);
+		nbl = NULL;
+		fallthrough;
+	case -EAGAIN:		/* conflock holds conflicting lock */
+		status = nfserr_denied;
+		dprintk("NFSD: nfsd4_lock: conflicting lock found!\n");
+		nfs4_set_lock_denied(conflock, &lock->lk_denied);
+		break;
+	case -EDEADLK:
+		status = nfserr_deadlock;
+		break;
+	default:
+		dprintk("NFSD: nfsd4_lock: vfs_lock_file() failed! status %d\n",err);
+		status = nfserrno(err);
+		break;
+	}
+out:
+	if (nbl) {
+		/* dequeue it if we queued it before */
+		if (fl_flags & FL_SLEEP) {
+			spin_lock(&nn->blocked_locks_lock);
+			if (!list_empty(&nbl->nbl_list) &&
+			    !list_empty(&nbl->nbl_lru)) {
+				list_del_init(&nbl->nbl_list);
+				list_del_init(&nbl->nbl_lru);
+				kref_put(&nbl->nbl_kref, free_nbl);
+			}
+			/* nbl can use one of lists to be linked to reaplist */
+			spin_unlock(&nn->blocked_locks_lock);
+		}
+		free_blocked_lock(nbl);
+	}
+	if (nf)
+		nfsd_file_put(nf);
+	if (lock_stp) {
+		/* Bump seqid manually if the 4.0 replay owner is openowner */
+		if (cstate->replay_owner &&
+		    cstate->replay_owner != &lock_sop->lo_owner &&
+		    seqid_mutating_err(ntohl(status)))
+			lock_sop->lo_owner.so_seqid++;
+
+		/*
+		 * If this is a new, never-before-used stateid, and we are
+		 * returning an error, then just go ahead and release it.
+		 */
+		if (status && new)
+			release_lock_stateid(lock_stp);
+
+		mutex_unlock(&lock_stp->st_mutex);
+
+		nfs4_put_stid(&lock_stp->st_stid);
+	}
+	if (open_stp)
+		nfs4_put_stid(&open_stp->st_stid);
+	nfsd4_bump_seqid(cstate, status);
+	if (conflock)
+		locks_free_lock(conflock);
+	return status;
+}
+
+/*
+ * The NFSv4 spec allows a client to do a LOCKT without holding an OPEN,
+ * so we do a temporary open here just to get an open file to pass to
+ * vfs_test_lock.
+ */
+static __be32 nfsd_test_lock(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file_lock *lock)
+{
+	struct nfsd_file *nf;
+	struct inode *inode;
+	__be32 err;
+
+	err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);
+	if (err)
+		return err;
+	inode = fhp->fh_dentry->d_inode;
+	inode_lock(inode); /* to block new leases till after test_lock: */
+	err = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ));
+	if (err)
+		goto out;
+	lock->fl_file = nf->nf_file;
+	err = nfserrno(vfs_test_lock(nf->nf_file, lock));
+	lock->fl_file = NULL;
+out:
+	inode_unlock(inode);
+	nfsd_file_put(nf);
+	return err;
+}
+
+/*
+ * LOCKT operation
+ */
+__be32
+nfsd4_lockt(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	    union nfsd4_op_u *u)
+{
+	struct nfsd4_lockt *lockt = &u->lockt;
+	struct file_lock *file_lock = NULL;
+	struct nfs4_lockowner *lo = NULL;
+	__be32 status;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	if (locks_in_grace(SVC_NET(rqstp)))
+		return nfserr_grace;
+
+	if (check_lock_length(lockt->lt_offset, lockt->lt_length))
+		 return nfserr_inval;
+
+	if (!nfsd4_has_session(cstate)) {
+		status = set_client(&lockt->lt_clientid, cstate, nn);
+		if (status)
+			goto out;
+	}
+
+	if ((status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0)))
+		goto out;
+
+	file_lock = locks_alloc_lock();
+	if (!file_lock) {
+		dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
+		status = nfserr_jukebox;
+		goto out;
+	}
+
+	switch (lockt->lt_type) {
+		case NFS4_READ_LT:
+		case NFS4_READW_LT:
+			file_lock->fl_type = F_RDLCK;
+			break;
+		case NFS4_WRITE_LT:
+		case NFS4_WRITEW_LT:
+			file_lock->fl_type = F_WRLCK;
+			break;
+		default:
+			dprintk("NFSD: nfs4_lockt: bad lock type!\n");
+			status = nfserr_inval;
+			goto out;
+	}
+
+	lo = find_lockowner_str(cstate->clp, &lockt->lt_owner);
+	if (lo)
+		file_lock->fl_owner = (fl_owner_t)lo;
+	file_lock->fl_pid = current->tgid;
+	file_lock->fl_flags = FL_POSIX;
+
+	file_lock->fl_start = lockt->lt_offset;
+	file_lock->fl_end = last_byte_offset(lockt->lt_offset, lockt->lt_length);
+
+	nfs4_transform_lock_offset(file_lock);
+
+	status = nfsd_test_lock(rqstp, &cstate->current_fh, file_lock);
+	if (status)
+		goto out;
+
+	if (file_lock->fl_type != F_UNLCK) {
+		status = nfserr_denied;
+		nfs4_set_lock_denied(file_lock, &lockt->lt_denied);
+	}
+out:
+	if (lo)
+		nfs4_put_stateowner(&lo->lo_owner);
+	if (file_lock)
+		locks_free_lock(file_lock);
+	return status;
+}
+
+__be32
+nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	    union nfsd4_op_u *u)
+{
+	struct nfsd4_locku *locku = &u->locku;
+	struct nfs4_ol_stateid *stp;
+	struct nfsd_file *nf = NULL;
+	struct file_lock *file_lock = NULL;
+	__be32 status;
+	int err;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+	dprintk("NFSD: nfsd4_locku: start=%Ld length=%Ld\n",
+		(long long) locku->lu_offset,
+		(long long) locku->lu_length);
+
+	if (check_lock_length(locku->lu_offset, locku->lu_length))
+		 return nfserr_inval;
+
+	status = nfs4_preprocess_seqid_op(cstate, locku->lu_seqid,
+					&locku->lu_stateid, NFS4_LOCK_STID,
+					&stp, nn);
+	if (status)
+		goto out;
+	nf = find_any_file(stp->st_stid.sc_file);
+	if (!nf) {
+		status = nfserr_lock_range;
+		goto put_stateid;
+	}
+	file_lock = locks_alloc_lock();
+	if (!file_lock) {
+		dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
+		status = nfserr_jukebox;
+		goto put_file;
+	}
+
+	file_lock->fl_type = F_UNLCK;
+	file_lock->fl_owner = (fl_owner_t)lockowner(nfs4_get_stateowner(stp->st_stateowner));
+	file_lock->fl_pid = current->tgid;
+	file_lock->fl_file = nf->nf_file;
+	file_lock->fl_flags = FL_POSIX;
+	file_lock->fl_lmops = &nfsd_posix_mng_ops;
+	file_lock->fl_start = locku->lu_offset;
+
+	file_lock->fl_end = last_byte_offset(locku->lu_offset,
+						locku->lu_length);
+	nfs4_transform_lock_offset(file_lock);
+
+	err = vfs_lock_file(nf->nf_file, F_SETLK, file_lock, NULL);
+	if (err) {
+		dprintk("NFSD: nfs4_locku: vfs_lock_file failed!\n");
+		goto out_nfserr;
+	}
+	nfs4_inc_and_copy_stateid(&locku->lu_stateid, &stp->st_stid);
+put_file:
+	nfsd_file_put(nf);
+put_stateid:
+	mutex_unlock(&stp->st_mutex);
+	nfs4_put_stid(&stp->st_stid);
+out:
+	nfsd4_bump_seqid(cstate, status);
+	if (file_lock)
+		locks_free_lock(file_lock);
+	return status;
+
+out_nfserr:
+	status = nfserrno(err);
+	goto put_file;
+}
+
+/*
+ * returns
+ * 	true:  locks held by lockowner
+ * 	false: no locks held by lockowner
+ */
+static bool
+check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner)
+{
+	struct file_lock *fl;
+	int status = false;
+	struct nfsd_file *nf = find_any_file(fp);
+	struct inode *inode;
+	struct file_lock_context *flctx;
+
+	if (!nf) {
+		/* Any valid lock stateid should have some sort of access */
+		WARN_ON_ONCE(1);
+		return status;
+	}
+
+	inode = locks_inode(nf->nf_file);
+	flctx = inode->i_flctx;
+
+	if (flctx && !list_empty_careful(&flctx->flc_posix)) {
+		spin_lock(&flctx->flc_lock);
+		list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
+			if (fl->fl_owner == (fl_owner_t)lowner) {
+				status = true;
+				break;
+			}
+		}
+		spin_unlock(&flctx->flc_lock);
+	}
+	nfsd_file_put(nf);
+	return status;
+}
+
+/**
+ * nfsd4_release_lockowner - process NFSv4.0 RELEASE_LOCKOWNER operations
+ * @rqstp: RPC transaction
+ * @cstate: NFSv4 COMPOUND state
+ * @u: RELEASE_LOCKOWNER arguments
+ *
+ * The lockowner's so_count is bumped when a lock record is added
+ * or when copying a conflicting lock. The latter case is brief,
+ * but can lead to fleeting false positives when looking for
+ * locks-in-use.
+ *
+ * Return values:
+ *   %nfs_ok: lockowner released or not found
+ *   %nfserr_locks_held: lockowner still in use
+ *   %nfserr_stale_clientid: clientid no longer active
+ *   %nfserr_expired: clientid not recognized
+ */
+__be32
+nfsd4_release_lockowner(struct svc_rqst *rqstp,
+			struct nfsd4_compound_state *cstate,
+			union nfsd4_op_u *u)
+{
+	struct nfsd4_release_lockowner *rlockowner = &u->release_lockowner;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+	clientid_t *clid = &rlockowner->rl_clientid;
+	struct nfs4_ol_stateid *stp;
+	struct nfs4_lockowner *lo;
+	struct nfs4_client *clp;
+	LIST_HEAD(reaplist);
+	__be32 status;
+
+	dprintk("nfsd4_release_lockowner clientid: (%08x/%08x):\n",
+		clid->cl_boot, clid->cl_id);
+
+	status = set_client(clid, cstate, nn);
+	if (status)
+		return status;
+	clp = cstate->clp;
+
+	spin_lock(&clp->cl_lock);
+	lo = find_lockowner_str_locked(clp, &rlockowner->rl_owner);
+	if (!lo) {
+		spin_unlock(&clp->cl_lock);
+		return nfs_ok;
+	}
+	if (atomic_read(&lo->lo_owner.so_count) != 2) {
+		spin_unlock(&clp->cl_lock);
+		nfs4_put_stateowner(&lo->lo_owner);
+		return nfserr_locks_held;
+	}
+	unhash_lockowner_locked(lo);
+	while (!list_empty(&lo->lo_owner.so_stateids)) {
+		stp = list_first_entry(&lo->lo_owner.so_stateids,
+				       struct nfs4_ol_stateid,
+				       st_perstateowner);
+		WARN_ON(!unhash_lock_stateid(stp));
+		put_ol_stateid_locked(stp, &reaplist);
+	}
+	spin_unlock(&clp->cl_lock);
+
+	free_ol_stateid_reaplist(&reaplist);
+	remove_blocked_locks(lo);
+	nfs4_put_stateowner(&lo->lo_owner);
+	return nfs_ok;
+}
+
+static inline struct nfs4_client_reclaim *
+alloc_reclaim(void)
+{
+	return kmalloc(sizeof(struct nfs4_client_reclaim), GFP_KERNEL);
+}
+
+bool
+nfs4_has_reclaimed_state(struct xdr_netobj name, struct nfsd_net *nn)
+{
+	struct nfs4_client_reclaim *crp;
+
+	crp = nfsd4_find_reclaim_client(name, nn);
+	return (crp && crp->cr_clp);
+}
+
+/*
+ * failure => all reset bets are off, nfserr_no_grace...
+ *
+ * The caller is responsible for freeing name.data if NULL is returned (it
+ * will be freed in nfs4_remove_reclaim_record in the normal case).
+ */
+struct nfs4_client_reclaim *
+nfs4_client_to_reclaim(struct xdr_netobj name, struct xdr_netobj princhash,
+		struct nfsd_net *nn)
+{
+	unsigned int strhashval;
+	struct nfs4_client_reclaim *crp;
+
+	crp = alloc_reclaim();
+	if (crp) {
+		strhashval = clientstr_hashval(name);
+		INIT_LIST_HEAD(&crp->cr_strhash);
+		list_add(&crp->cr_strhash, &nn->reclaim_str_hashtbl[strhashval]);
+		crp->cr_name.data = name.data;
+		crp->cr_name.len = name.len;
+		crp->cr_princhash.data = princhash.data;
+		crp->cr_princhash.len = princhash.len;
+		crp->cr_clp = NULL;
+		nn->reclaim_str_hashtbl_size++;
+	}
+	return crp;
+}
+
+void
+nfs4_remove_reclaim_record(struct nfs4_client_reclaim *crp, struct nfsd_net *nn)
+{
+	list_del(&crp->cr_strhash);
+	kfree(crp->cr_name.data);
+	kfree(crp->cr_princhash.data);
+	kfree(crp);
+	nn->reclaim_str_hashtbl_size--;
+}
+
+void
+nfs4_release_reclaim(struct nfsd_net *nn)
+{
+	struct nfs4_client_reclaim *crp = NULL;
+	int i;
+
+	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
+		while (!list_empty(&nn->reclaim_str_hashtbl[i])) {
+			crp = list_entry(nn->reclaim_str_hashtbl[i].next,
+			                struct nfs4_client_reclaim, cr_strhash);
+			nfs4_remove_reclaim_record(crp, nn);
+		}
+	}
+	WARN_ON_ONCE(nn->reclaim_str_hashtbl_size);
+}
+
+/*
+ * called from OPEN, CLAIM_PREVIOUS with a new clientid. */
+struct nfs4_client_reclaim *
+nfsd4_find_reclaim_client(struct xdr_netobj name, struct nfsd_net *nn)
+{
+	unsigned int strhashval;
+	struct nfs4_client_reclaim *crp = NULL;
+
+	strhashval = clientstr_hashval(name);
+	list_for_each_entry(crp, &nn->reclaim_str_hashtbl[strhashval], cr_strhash) {
+		if (compare_blob(&crp->cr_name, &name) == 0) {
+			return crp;
+		}
+	}
+	return NULL;
+}
+
+__be32
+nfs4_check_open_reclaim(struct nfs4_client *clp)
+{
+	if (test_bit(NFSD4_CLIENT_RECLAIM_COMPLETE, &clp->cl_flags))
+		return nfserr_no_grace;
+
+	if (nfsd4_client_record_check(clp))
+		return nfserr_reclaim_bad;
+
+	return nfs_ok;
+}
+
+/*
+ * Since the lifetime of a delegation isn't limited to that of an open, a
+ * client may quite reasonably hang on to a delegation as long as it has
+ * the inode cached.  This becomes an obvious problem the first time a
+ * client's inode cache approaches the size of the server's total memory.
+ *
+ * For now we avoid this problem by imposing a hard limit on the number
+ * of delegations, which varies according to the server's memory size.
+ */
+static void
+set_max_delegations(void)
+{
+	/*
+	 * Allow at most 4 delegations per megabyte of RAM.  Quick
+	 * estimates suggest that in the worst case (where every delegation
+	 * is for a different inode), a delegation could take about 1.5K,
+	 * giving a worst case usage of about 6% of memory.
+	 */
+	max_delegations = nr_free_buffer_pages() >> (20 - 2 - PAGE_SHIFT);
+}
+
+static int nfs4_state_create_net(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	int i;
+
+	nn->conf_id_hashtbl = kmalloc_array(CLIENT_HASH_SIZE,
+					    sizeof(struct list_head),
+					    GFP_KERNEL);
+	if (!nn->conf_id_hashtbl)
+		goto err;
+	nn->unconf_id_hashtbl = kmalloc_array(CLIENT_HASH_SIZE,
+					      sizeof(struct list_head),
+					      GFP_KERNEL);
+	if (!nn->unconf_id_hashtbl)
+		goto err_unconf_id;
+	nn->sessionid_hashtbl = kmalloc_array(SESSION_HASH_SIZE,
+					      sizeof(struct list_head),
+					      GFP_KERNEL);
+	if (!nn->sessionid_hashtbl)
+		goto err_sessionid;
+
+	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
+		INIT_LIST_HEAD(&nn->conf_id_hashtbl[i]);
+		INIT_LIST_HEAD(&nn->unconf_id_hashtbl[i]);
+	}
+	for (i = 0; i < SESSION_HASH_SIZE; i++)
+		INIT_LIST_HEAD(&nn->sessionid_hashtbl[i]);
+	nn->conf_name_tree = RB_ROOT;
+	nn->unconf_name_tree = RB_ROOT;
+	nn->boot_time = ktime_get_real_seconds();
+	nn->grace_ended = false;
+	nn->nfsd4_manager.block_opens = true;
+	INIT_LIST_HEAD(&nn->nfsd4_manager.list);
+	INIT_LIST_HEAD(&nn->client_lru);
+	INIT_LIST_HEAD(&nn->close_lru);
+	INIT_LIST_HEAD(&nn->del_recall_lru);
+	spin_lock_init(&nn->client_lock);
+	spin_lock_init(&nn->s2s_cp_lock);
+	idr_init(&nn->s2s_cp_stateids);
+
+	spin_lock_init(&nn->blocked_locks_lock);
+	INIT_LIST_HEAD(&nn->blocked_locks_lru);
+
+	INIT_DELAYED_WORK(&nn->laundromat_work, laundromat_main);
+	INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, courtesy_client_reaper);
+	get_net(net);
+
+	return 0;
+
+err_sessionid:
+	kfree(nn->unconf_id_hashtbl);
+err_unconf_id:
+	kfree(nn->conf_id_hashtbl);
+err:
+	return -ENOMEM;
+}
+
+static void
+nfs4_state_destroy_net(struct net *net)
+{
+	int i;
+	struct nfs4_client *clp = NULL;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
+		while (!list_empty(&nn->conf_id_hashtbl[i])) {
+			clp = list_entry(nn->conf_id_hashtbl[i].next, struct nfs4_client, cl_idhash);
+			destroy_client(clp);
+		}
+	}
+
+	WARN_ON(!list_empty(&nn->blocked_locks_lru));
+
+	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
+		while (!list_empty(&nn->unconf_id_hashtbl[i])) {
+			clp = list_entry(nn->unconf_id_hashtbl[i].next, struct nfs4_client, cl_idhash);
+			destroy_client(clp);
+		}
+	}
+
+	kfree(nn->sessionid_hashtbl);
+	kfree(nn->unconf_id_hashtbl);
+	kfree(nn->conf_id_hashtbl);
+	put_net(net);
+}
+
+int
+nfs4_state_start_net(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	int ret;
+
+	ret = nfs4_state_create_net(net);
+	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)
+		goto skip_grace;
+	printk(KERN_INFO "NFSD: starting %lld-second grace period (net %x)\n",
+	       nn->nfsd4_grace, net->ns.inum);
+	trace_nfsd_grace_start(nn);
+	queue_delayed_work(laundry_wq, &nn->laundromat_work, nn->nfsd4_grace * HZ);
+	return 0;
+
+skip_grace:
+	printk(KERN_INFO "NFSD: no clients to reclaim, skipping NFSv4 grace period (net %x)\n",
+			net->ns.inum);
+	queue_delayed_work(laundry_wq, &nn->laundromat_work, nn->nfsd4_lease * HZ);
+	nfsd4_end_grace(nn);
+	return 0;
+}
+
+/* initialization to perform when the nfsd service is started: */
+
+int
+nfs4_state_start(void)
+{
+	int ret;
+
+	ret = nfsd4_create_callback_queue();
+	if (ret)
+		return ret;
+
+	set_max_delegations();
+	return 0;
+}
+
+void
+nfs4_state_shutdown_net(struct net *net)
+{
+	struct nfs4_delegation *dp = NULL;
+	struct list_head *pos, *next, reaplist;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	cancel_delayed_work_sync(&nn->laundromat_work);
+	locks_end_grace(&nn->nfsd4_manager);
+
+	INIT_LIST_HEAD(&reaplist);
+	spin_lock(&state_lock);
+	list_for_each_safe(pos, next, &nn->del_recall_lru) {
+		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
+		WARN_ON(!unhash_delegation_locked(dp));
+		list_add(&dp->dl_recall_lru, &reaplist);
+	}
+	spin_unlock(&state_lock);
+	list_for_each_safe(pos, next, &reaplist) {
+		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
+		list_del_init(&dp->dl_recall_lru);
+		destroy_unhashed_deleg(dp);
+	}
+
+	nfsd4_client_tracking_exit(net);
+	nfs4_state_destroy_net(net);
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+	nfsd4_ssc_shutdown_umount(nn);
+#endif
+}
+
+void
+nfs4_state_shutdown(void)
+{
+	nfsd4_destroy_callback_queue();
+}
+
+static void
+get_stateid(struct nfsd4_compound_state *cstate, stateid_t *stateid)
+{
+	if (HAS_CSTATE_FLAG(cstate, CURRENT_STATE_ID_FLAG) &&
+	    CURRENT_STATEID(stateid))
+		memcpy(stateid, &cstate->current_stateid, sizeof(stateid_t));
+}
+
+static void
+put_stateid(struct nfsd4_compound_state *cstate, stateid_t *stateid)
+{
+	if (cstate->minorversion) {
+		memcpy(&cstate->current_stateid, stateid, sizeof(stateid_t));
+		SET_CSTATE_FLAG(cstate, CURRENT_STATE_ID_FLAG);
+	}
+}
+
+void
+clear_current_stateid(struct nfsd4_compound_state *cstate)
+{
+	CLEAR_CSTATE_FLAG(cstate, CURRENT_STATE_ID_FLAG);
+}
+
+/*
+ * functions to set current state id
+ */
+void
+nfsd4_set_opendowngradestateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	put_stateid(cstate, &u->open_downgrade.od_stateid);
+}
+
+void
+nfsd4_set_openstateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	put_stateid(cstate, &u->open.op_stateid);
+}
+
+void
+nfsd4_set_closestateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	put_stateid(cstate, &u->close.cl_stateid);
+}
+
+void
+nfsd4_set_lockstateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	put_stateid(cstate, &u->lock.lk_resp_stateid);
+}
+
+/*
+ * functions to consume current state id
+ */
+
+void
+nfsd4_get_opendowngradestateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	get_stateid(cstate, &u->open_downgrade.od_stateid);
+}
+
+void
+nfsd4_get_delegreturnstateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	get_stateid(cstate, &u->delegreturn.dr_stateid);
+}
+
+void
+nfsd4_get_freestateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	get_stateid(cstate, &u->free_stateid.fr_stateid);
+}
+
+void
+nfsd4_get_setattrstateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	get_stateid(cstate, &u->setattr.sa_stateid);
+}
+
+void
+nfsd4_get_closestateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	get_stateid(cstate, &u->close.cl_stateid);
+}
+
+void
+nfsd4_get_lockustateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	get_stateid(cstate, &u->locku.lu_stateid);
+}
+
+void
+nfsd4_get_readstateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	get_stateid(cstate, &u->read.rd_stateid);
+}
+
+void
+nfsd4_get_writestateid(struct nfsd4_compound_state *cstate,
+		union nfsd4_op_u *u)
+{
+	get_stateid(cstate, &u->write.wr_stateid);
+}