diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
new file mode 100644
index 0000000..231cebc
--- /dev/null
+++ b/fs/nfs/nfs4state.c
@@ -0,0 +1,932 @@
+/*
+ *  fs/nfs/nfs4state.c
+ *
+ *  Client-side XDR for NFSv4.
+ *
+ *  Copyright (c) 2002 The Regents of the University of Michigan.
+ *  All rights reserved.
+ *
+ *  Kendrick Smith <kmsmith@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.
+ *
+ * Implementation of the NFSv4 state model.  For the time being,
+ * this is minimal, but will be made much more complex in a
+ * subsequent patch.
+ */
+
+#include <linux/config.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_idmap.h>
+#include <linux/workqueue.h>
+#include <linux/bitops.h>
+
+#include "callback.h"
+#include "delegation.h"
+
+#define OPENOWNER_POOL_SIZE	8
+
+static DEFINE_SPINLOCK(state_spinlock);
+
+nfs4_stateid zero_stateid;
+
+#if 0
+nfs4_stateid one_stateid =
+	{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+#endif
+
+static LIST_HEAD(nfs4_clientid_list);
+
+static void nfs4_recover_state(void *);
+extern void nfs4_renew_state(void *);
+
+void
+init_nfsv4_state(struct nfs_server *server)
+{
+	server->nfs4_state = NULL;
+	INIT_LIST_HEAD(&server->nfs4_siblings);
+}
+
+void
+destroy_nfsv4_state(struct nfs_server *server)
+{
+	if (server->mnt_path) {
+		kfree(server->mnt_path);
+		server->mnt_path = NULL;
+	}
+	if (server->nfs4_state) {
+		nfs4_put_client(server->nfs4_state);
+		server->nfs4_state = NULL;
+	}
+}
+
+/*
+ * nfs4_get_client(): returns an empty client structure
+ * nfs4_put_client(): drops reference to client structure
+ *
+ * Since these are allocated/deallocated very rarely, we don't
+ * bother putting them in a slab cache...
+ */
+static struct nfs4_client *
+nfs4_alloc_client(struct in_addr *addr)
+{
+	struct nfs4_client *clp;
+
+	if (nfs_callback_up() < 0)
+		return NULL;
+	if ((clp = kmalloc(sizeof(*clp), GFP_KERNEL)) == NULL) {
+		nfs_callback_down();
+		return NULL;
+	}
+	memset(clp, 0, sizeof(*clp));
+	memcpy(&clp->cl_addr, addr, sizeof(clp->cl_addr));
+	init_rwsem(&clp->cl_sem);
+	INIT_LIST_HEAD(&clp->cl_delegations);
+	INIT_LIST_HEAD(&clp->cl_state_owners);
+	INIT_LIST_HEAD(&clp->cl_unused);
+	spin_lock_init(&clp->cl_lock);
+	atomic_set(&clp->cl_count, 1);
+	INIT_WORK(&clp->cl_recoverd, nfs4_recover_state, clp);
+	INIT_WORK(&clp->cl_renewd, nfs4_renew_state, clp);
+	INIT_LIST_HEAD(&clp->cl_superblocks);
+	init_waitqueue_head(&clp->cl_waitq);
+	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS4 client");
+	clp->cl_boot_time = CURRENT_TIME;
+	clp->cl_state = 1 << NFS4CLNT_OK;
+	return clp;
+}
+
+static void
+nfs4_free_client(struct nfs4_client *clp)
+{
+	struct nfs4_state_owner *sp;
+
+	while (!list_empty(&clp->cl_unused)) {
+		sp = list_entry(clp->cl_unused.next,
+				struct nfs4_state_owner,
+				so_list);
+		list_del(&sp->so_list);
+		kfree(sp);
+	}
+	BUG_ON(!list_empty(&clp->cl_state_owners));
+	if (clp->cl_cred)
+		put_rpccred(clp->cl_cred);
+	nfs_idmap_delete(clp);
+	if (clp->cl_rpcclient)
+		rpc_shutdown_client(clp->cl_rpcclient);
+	kfree(clp);
+	nfs_callback_down();
+}
+
+static struct nfs4_client *__nfs4_find_client(struct in_addr *addr)
+{
+	struct nfs4_client *clp;
+	list_for_each_entry(clp, &nfs4_clientid_list, cl_servers) {
+		if (memcmp(&clp->cl_addr, addr, sizeof(clp->cl_addr)) == 0) {
+			atomic_inc(&clp->cl_count);
+			return clp;
+		}
+	}
+	return NULL;
+}
+
+struct nfs4_client *nfs4_find_client(struct in_addr *addr)
+{
+	struct nfs4_client *clp;
+	spin_lock(&state_spinlock);
+	clp = __nfs4_find_client(addr);
+	spin_unlock(&state_spinlock);
+	return clp;
+}
+
+struct nfs4_client *
+nfs4_get_client(struct in_addr *addr)
+{
+	struct nfs4_client *clp, *new = NULL;
+
+	spin_lock(&state_spinlock);
+	for (;;) {
+		clp = __nfs4_find_client(addr);
+		if (clp != NULL)
+			break;
+		clp = new;
+		if (clp != NULL) {
+			list_add(&clp->cl_servers, &nfs4_clientid_list);
+			new = NULL;
+			break;
+		}
+		spin_unlock(&state_spinlock);
+		new = nfs4_alloc_client(addr);
+		spin_lock(&state_spinlock);
+		if (new == NULL)
+			break;
+	}
+	spin_unlock(&state_spinlock);
+	if (new)
+		nfs4_free_client(new);
+	return clp;
+}
+
+void
+nfs4_put_client(struct nfs4_client *clp)
+{
+	if (!atomic_dec_and_lock(&clp->cl_count, &state_spinlock))
+		return;
+	list_del(&clp->cl_servers);
+	spin_unlock(&state_spinlock);
+	BUG_ON(!list_empty(&clp->cl_superblocks));
+	wake_up_all(&clp->cl_waitq);
+	rpc_wake_up(&clp->cl_rpcwaitq);
+	nfs4_kill_renewd(clp);
+	nfs4_free_client(clp);
+}
+
+static int __nfs4_init_client(struct nfs4_client *clp)
+{
+	int status = nfs4_proc_setclientid(clp, NFS4_CALLBACK, nfs_callback_tcpport);
+	if (status == 0)
+		status = nfs4_proc_setclientid_confirm(clp);
+	if (status == 0)
+		nfs4_schedule_state_renewal(clp);
+	return status;
+}
+
+int nfs4_init_client(struct nfs4_client *clp)
+{
+	return nfs4_map_errors(__nfs4_init_client(clp));
+}
+
+u32
+nfs4_alloc_lockowner_id(struct nfs4_client *clp)
+{
+	return clp->cl_lockowner_id ++;
+}
+
+static struct nfs4_state_owner *
+nfs4_client_grab_unused(struct nfs4_client *clp, struct rpc_cred *cred)
+{
+	struct nfs4_state_owner *sp = NULL;
+
+	if (!list_empty(&clp->cl_unused)) {
+		sp = list_entry(clp->cl_unused.next, struct nfs4_state_owner, so_list);
+		atomic_inc(&sp->so_count);
+		sp->so_cred = cred;
+		list_move(&sp->so_list, &clp->cl_state_owners);
+		clp->cl_nunused--;
+	}
+	return sp;
+}
+
+static struct nfs4_state_owner *
+nfs4_find_state_owner(struct nfs4_client *clp, struct rpc_cred *cred)
+{
+	struct nfs4_state_owner *sp, *res = NULL;
+
+	list_for_each_entry(sp, &clp->cl_state_owners, so_list) {
+		if (sp->so_cred != cred)
+			continue;
+		atomic_inc(&sp->so_count);
+		/* Move to the head of the list */
+		list_move(&sp->so_list, &clp->cl_state_owners);
+		res = sp;
+		break;
+	}
+	return res;
+}
+
+/*
+ * nfs4_alloc_state_owner(): this is called on the OPEN or CREATE path to
+ * create a new state_owner.
+ *
+ */
+static struct nfs4_state_owner *
+nfs4_alloc_state_owner(void)
+{
+	struct nfs4_state_owner *sp;
+
+	sp = kmalloc(sizeof(*sp),GFP_KERNEL);
+	if (!sp)
+		return NULL;
+	init_MUTEX(&sp->so_sema);
+	sp->so_seqid = 0;                 /* arbitrary */
+	INIT_LIST_HEAD(&sp->so_states);
+	INIT_LIST_HEAD(&sp->so_delegations);
+	atomic_set(&sp->so_count, 1);
+	return sp;
+}
+
+void
+nfs4_drop_state_owner(struct nfs4_state_owner *sp)
+{
+	struct nfs4_client *clp = sp->so_client;
+	spin_lock(&clp->cl_lock);
+	list_del_init(&sp->so_list);
+	spin_unlock(&clp->cl_lock);
+}
+
+/*
+ * Note: must be called with clp->cl_sem held in order to prevent races
+ *       with reboot recovery!
+ */
+struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *server, struct rpc_cred *cred)
+{
+	struct nfs4_client *clp = server->nfs4_state;
+	struct nfs4_state_owner *sp, *new;
+
+	get_rpccred(cred);
+	new = nfs4_alloc_state_owner();
+	spin_lock(&clp->cl_lock);
+	sp = nfs4_find_state_owner(clp, cred);
+	if (sp == NULL)
+		sp = nfs4_client_grab_unused(clp, cred);
+	if (sp == NULL && new != NULL) {
+		list_add(&new->so_list, &clp->cl_state_owners);
+		new->so_client = clp;
+		new->so_id = nfs4_alloc_lockowner_id(clp);
+		new->so_cred = cred;
+		sp = new;
+		new = NULL;
+	}
+	spin_unlock(&clp->cl_lock);
+	if (new)
+		kfree(new);
+	if (sp != NULL)
+		return sp;
+	put_rpccred(cred);
+	return NULL;
+}
+
+/*
+ * Must be called with clp->cl_sem held in order to avoid races
+ * with state recovery...
+ */
+void nfs4_put_state_owner(struct nfs4_state_owner *sp)
+{
+	struct nfs4_client *clp = sp->so_client;
+	struct rpc_cred *cred = sp->so_cred;
+
+	if (!atomic_dec_and_lock(&sp->so_count, &clp->cl_lock))
+		return;
+	if (clp->cl_nunused >= OPENOWNER_POOL_SIZE)
+		goto out_free;
+	if (list_empty(&sp->so_list))
+		goto out_free;
+	list_move(&sp->so_list, &clp->cl_unused);
+	clp->cl_nunused++;
+	spin_unlock(&clp->cl_lock);
+	put_rpccred(cred);
+	cred = NULL;
+	return;
+out_free:
+	list_del(&sp->so_list);
+	spin_unlock(&clp->cl_lock);
+	put_rpccred(cred);
+	kfree(sp);
+}
+
+static struct nfs4_state *
+nfs4_alloc_open_state(void)
+{
+	struct nfs4_state *state;
+
+	state = kmalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return NULL;
+	state->state = 0;
+	state->nreaders = 0;
+	state->nwriters = 0;
+	state->flags = 0;
+	memset(state->stateid.data, 0, sizeof(state->stateid.data));
+	atomic_set(&state->count, 1);
+	INIT_LIST_HEAD(&state->lock_states);
+	init_MUTEX(&state->lock_sema);
+	rwlock_init(&state->state_lock);
+	return state;
+}
+
+static struct nfs4_state *
+__nfs4_find_state(struct inode *inode, struct rpc_cred *cred, mode_t mode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs4_state *state;
+
+	mode &= (FMODE_READ|FMODE_WRITE);
+	list_for_each_entry(state, &nfsi->open_states, inode_states) {
+		if (state->owner->so_cred != cred)
+			continue;
+		if ((mode & FMODE_READ) != 0 && state->nreaders == 0)
+			continue;
+		if ((mode & FMODE_WRITE) != 0 && state->nwriters == 0)
+			continue;
+		if ((state->state & mode) != mode)
+			continue;
+		atomic_inc(&state->count);
+		if (mode & FMODE_READ)
+			state->nreaders++;
+		if (mode & FMODE_WRITE)
+			state->nwriters++;
+		return state;
+	}
+	return NULL;
+}
+
+static struct nfs4_state *
+__nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs4_state *state;
+
+	list_for_each_entry(state, &nfsi->open_states, inode_states) {
+		/* Is this in the process of being freed? */
+		if (state->nreaders == 0 && state->nwriters == 0)
+			continue;
+		if (state->owner == owner) {
+			atomic_inc(&state->count);
+			return state;
+		}
+	}
+	return NULL;
+}
+
+struct nfs4_state *
+nfs4_find_state(struct inode *inode, struct rpc_cred *cred, mode_t mode)
+{
+	struct nfs4_state *state;
+
+	spin_lock(&inode->i_lock);
+	state = __nfs4_find_state(inode, cred, mode);
+	spin_unlock(&inode->i_lock);
+	return state;
+}
+
+static void
+nfs4_free_open_state(struct nfs4_state *state)
+{
+	kfree(state);
+}
+
+struct nfs4_state *
+nfs4_get_open_state(struct inode *inode, struct nfs4_state_owner *owner)
+{
+	struct nfs4_state *state, *new;
+	struct nfs_inode *nfsi = NFS_I(inode);
+
+	spin_lock(&inode->i_lock);
+	state = __nfs4_find_state_byowner(inode, owner);
+	spin_unlock(&inode->i_lock);
+	if (state)
+		goto out;
+	new = nfs4_alloc_open_state();
+	spin_lock(&inode->i_lock);
+	state = __nfs4_find_state_byowner(inode, owner);
+	if (state == NULL && new != NULL) {
+		state = new;
+		/* Caller *must* be holding owner->so_sem */
+		/* Note: The reclaim code dictates that we add stateless
+		 * and read-only stateids to the end of the list */
+		list_add_tail(&state->open_states, &owner->so_states);
+		state->owner = owner;
+		atomic_inc(&owner->so_count);
+		list_add(&state->inode_states, &nfsi->open_states);
+		state->inode = igrab(inode);
+		spin_unlock(&inode->i_lock);
+	} else {
+		spin_unlock(&inode->i_lock);
+		if (new)
+			nfs4_free_open_state(new);
+	}
+out:
+	return state;
+}
+
+/*
+ * Beware! Caller must be holding exactly one
+ * reference to clp->cl_sem and owner->so_sema!
+ */
+void nfs4_put_open_state(struct nfs4_state *state)
+{
+	struct inode *inode = state->inode;
+	struct nfs4_state_owner *owner = state->owner;
+
+	if (!atomic_dec_and_lock(&state->count, &inode->i_lock))
+		return;
+	if (!list_empty(&state->inode_states))
+		list_del(&state->inode_states);
+	spin_unlock(&inode->i_lock);
+	list_del(&state->open_states);
+	iput(inode);
+	BUG_ON (state->state != 0);
+	nfs4_free_open_state(state);
+	nfs4_put_state_owner(owner);
+}
+
+/*
+ * Beware! Caller must be holding no references to clp->cl_sem!
+ * of owner->so_sema!
+ */
+void nfs4_close_state(struct nfs4_state *state, mode_t mode)
+{
+	struct inode *inode = state->inode;
+	struct nfs4_state_owner *owner = state->owner;
+	struct nfs4_client *clp = owner->so_client;
+	int newstate;
+
+	atomic_inc(&owner->so_count);
+	down_read(&clp->cl_sem);
+	down(&owner->so_sema);
+	/* Protect against nfs4_find_state() */
+	spin_lock(&inode->i_lock);
+	if (mode & FMODE_READ)
+		state->nreaders--;
+	if (mode & FMODE_WRITE)
+		state->nwriters--;
+	if (state->nwriters == 0) {
+		if (state->nreaders == 0)
+			list_del_init(&state->inode_states);
+		/* See reclaim code */
+		list_move_tail(&state->open_states, &owner->so_states);
+	}
+	spin_unlock(&inode->i_lock);
+	newstate = 0;
+	if (state->state != 0) {
+		if (state->nreaders)
+			newstate |= FMODE_READ;
+		if (state->nwriters)
+			newstate |= FMODE_WRITE;
+		if (state->state == newstate)
+			goto out;
+		if (nfs4_do_close(inode, state, newstate) == -EINPROGRESS)
+			return;
+	}
+out:
+	nfs4_put_open_state(state);
+	up(&owner->so_sema);
+	nfs4_put_state_owner(owner);
+	up_read(&clp->cl_sem);
+}
+
+/*
+ * Search the state->lock_states for an existing lock_owner
+ * that is compatible with current->files
+ */
+static struct nfs4_lock_state *
+__nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
+{
+	struct nfs4_lock_state *pos;
+	list_for_each_entry(pos, &state->lock_states, ls_locks) {
+		if (pos->ls_owner != fl_owner)
+			continue;
+		atomic_inc(&pos->ls_count);
+		return pos;
+	}
+	return NULL;
+}
+
+struct nfs4_lock_state *
+nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
+{
+	struct nfs4_lock_state *lsp;
+	read_lock(&state->state_lock);
+	lsp = __nfs4_find_lock_state(state, fl_owner);
+	read_unlock(&state->state_lock);
+	return lsp;
+}
+
+/*
+ * Return a compatible lock_state. If no initialized lock_state structure
+ * exists, return an uninitialized one.
+ *
+ * The caller must be holding state->lock_sema
+ */
+static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
+{
+	struct nfs4_lock_state *lsp;
+	struct nfs4_client *clp = state->owner->so_client;
+
+	lsp = kmalloc(sizeof(*lsp), GFP_KERNEL);
+	if (lsp == NULL)
+		return NULL;
+	lsp->ls_flags = 0;
+	lsp->ls_seqid = 0;	/* arbitrary */
+	lsp->ls_id = -1; 
+	memset(lsp->ls_stateid.data, 0, sizeof(lsp->ls_stateid.data));
+	atomic_set(&lsp->ls_count, 1);
+	lsp->ls_owner = fl_owner;
+	INIT_LIST_HEAD(&lsp->ls_locks);
+	spin_lock(&clp->cl_lock);
+	lsp->ls_id = nfs4_alloc_lockowner_id(clp);
+	spin_unlock(&clp->cl_lock);
+	return lsp;
+}
+
+/*
+ * Return a compatible lock_state. If no initialized lock_state structure
+ * exists, return an uninitialized one.
+ *
+ * The caller must be holding state->lock_sema and clp->cl_sem
+ */
+struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t owner)
+{
+	struct nfs4_lock_state * lsp;
+	
+	lsp = nfs4_find_lock_state(state, owner);
+	if (lsp == NULL)
+		lsp = nfs4_alloc_lock_state(state, owner);
+	return lsp;
+}
+
+/*
+ * Byte-range lock aware utility to initialize the stateid of read/write
+ * requests.
+ */
+void
+nfs4_copy_stateid(nfs4_stateid *dst, struct nfs4_state *state, fl_owner_t fl_owner)
+{
+	if (test_bit(LK_STATE_IN_USE, &state->flags)) {
+		struct nfs4_lock_state *lsp;
+
+		lsp = nfs4_find_lock_state(state, fl_owner);
+		if (lsp) {
+			memcpy(dst, &lsp->ls_stateid, sizeof(*dst));
+			nfs4_put_lock_state(lsp);
+			return;
+		}
+	}
+	memcpy(dst, &state->stateid, sizeof(*dst));
+}
+
+/*
+* Called with state->lock_sema and clp->cl_sem held.
+*/
+void nfs4_increment_lock_seqid(int status, struct nfs4_lock_state *lsp)
+{
+	if (status == NFS_OK || seqid_mutating_err(-status))
+		lsp->ls_seqid++;
+}
+
+/* 
+* Check to see if the request lock (type FL_UNLK) effects the fl lock.
+*
+* fl and request must have the same posix owner
+*
+* return: 
+* 0 -> fl not effected by request
+* 1 -> fl consumed by request
+*/
+
+static int
+nfs4_check_unlock(struct file_lock *fl, struct file_lock *request)
+{
+	if (fl->fl_start >= request->fl_start && fl->fl_end <= request->fl_end)
+		return 1;
+	return 0;
+}
+
+/*
+ * Post an initialized lock_state on the state->lock_states list.
+ */
+void nfs4_notify_setlk(struct nfs4_state *state, struct file_lock *request, struct nfs4_lock_state *lsp)
+{
+	if (!list_empty(&lsp->ls_locks))
+		return;
+	atomic_inc(&lsp->ls_count);
+	write_lock(&state->state_lock);
+	list_add(&lsp->ls_locks, &state->lock_states);
+	set_bit(LK_STATE_IN_USE, &state->flags);
+	write_unlock(&state->state_lock);
+}
+
+/* 
+ * to decide to 'reap' lock state:
+ * 1) search i_flock for file_locks with fl.lock_state = to ls.
+ * 2) determine if unlock will consume found lock. 
+ * 	if so, reap
+ *
+ * 	else, don't reap.
+ *
+ */
+void
+nfs4_notify_unlck(struct nfs4_state *state, struct file_lock *request, struct nfs4_lock_state *lsp)
+{
+	struct inode *inode = state->inode;
+	struct file_lock *fl;
+
+	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
+		if (!(fl->fl_flags & FL_POSIX))
+			continue;
+		if (fl->fl_owner != lsp->ls_owner)
+			continue;
+		/* Exit if we find at least one lock which is not consumed */
+		if (nfs4_check_unlock(fl,request) == 0)
+			return;
+	}
+
+	write_lock(&state->state_lock);
+	list_del_init(&lsp->ls_locks);
+	if (list_empty(&state->lock_states))
+		clear_bit(LK_STATE_IN_USE, &state->flags);
+	write_unlock(&state->state_lock);
+	nfs4_put_lock_state(lsp);
+}
+
+/*
+ * Release reference to lock_state, and free it if we see that
+ * it is no longer in use
+ */
+void
+nfs4_put_lock_state(struct nfs4_lock_state *lsp)
+{
+	if (!atomic_dec_and_test(&lsp->ls_count))
+		return;
+	BUG_ON (!list_empty(&lsp->ls_locks));
+	kfree(lsp);
+}
+
+/*
+* Called with sp->so_sema and clp->cl_sem held.
+*
+* Increment the seqid if the OPEN/OPEN_DOWNGRADE/CLOSE succeeded, or
+* failed with a seqid incrementing error -
+* see comments nfs_fs.h:seqid_mutating_error()
+*/
+void nfs4_increment_seqid(int status, struct nfs4_state_owner *sp)
+{
+	if (status == NFS_OK || seqid_mutating_err(-status))
+		sp->so_seqid++;
+	/* If the server returns BAD_SEQID, unhash state_owner here */
+	if (status == -NFS4ERR_BAD_SEQID)
+		nfs4_drop_state_owner(sp);
+}
+
+static int reclaimer(void *);
+struct reclaimer_args {
+	struct nfs4_client *clp;
+	struct completion complete;
+};
+
+/*
+ * State recovery routine
+ */
+void
+nfs4_recover_state(void *data)
+{
+	struct nfs4_client *clp = (struct nfs4_client *)data;
+	struct reclaimer_args args = {
+		.clp = clp,
+	};
+	might_sleep();
+
+	init_completion(&args.complete);
+
+	if (kernel_thread(reclaimer, &args, CLONE_KERNEL) < 0)
+		goto out_failed_clear;
+	wait_for_completion(&args.complete);
+	return;
+out_failed_clear:
+	set_bit(NFS4CLNT_OK, &clp->cl_state);
+	wake_up_all(&clp->cl_waitq);
+	rpc_wake_up(&clp->cl_rpcwaitq);
+}
+
+/*
+ * Schedule a state recovery attempt
+ */
+void
+nfs4_schedule_state_recovery(struct nfs4_client *clp)
+{
+	if (!clp)
+		return;
+	if (test_and_clear_bit(NFS4CLNT_OK, &clp->cl_state))
+		schedule_work(&clp->cl_recoverd);
+}
+
+static int nfs4_reclaim_locks(struct nfs4_state_recovery_ops *ops, struct nfs4_state *state)
+{
+	struct inode *inode = state->inode;
+	struct file_lock *fl;
+	int status = 0;
+
+	for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
+		if (!(fl->fl_flags & FL_POSIX))
+			continue;
+		if (((struct nfs_open_context *)fl->fl_file->private_data)->state != state)
+			continue;
+		status = ops->recover_lock(state, fl);
+		if (status >= 0)
+			continue;
+		switch (status) {
+			default:
+				printk(KERN_ERR "%s: unhandled error %d. Zeroing state\n",
+						__FUNCTION__, status);
+			case -NFS4ERR_EXPIRED:
+			case -NFS4ERR_NO_GRACE:
+			case -NFS4ERR_RECLAIM_BAD:
+			case -NFS4ERR_RECLAIM_CONFLICT:
+				/* kill_proc(fl->fl_owner, SIGLOST, 1); */
+				break;
+			case -NFS4ERR_STALE_CLIENTID:
+				goto out_err;
+		}
+	}
+	return 0;
+out_err:
+	return status;
+}
+
+static int nfs4_reclaim_open_state(struct nfs4_state_recovery_ops *ops, struct nfs4_state_owner *sp)
+{
+	struct nfs4_state *state;
+	struct nfs4_lock_state *lock;
+	int status = 0;
+
+	/* Note: we rely on the sp->so_states list being ordered 
+	 * so that we always reclaim open(O_RDWR) and/or open(O_WRITE)
+	 * states first.
+	 * This is needed to ensure that the server won't give us any
+	 * read delegations that we have to return if, say, we are
+	 * recovering after a network partition or a reboot from a
+	 * server that doesn't support a grace period.
+	 */
+	list_for_each_entry(state, &sp->so_states, open_states) {
+		if (state->state == 0)
+			continue;
+		status = ops->recover_open(sp, state);
+		list_for_each_entry(lock, &state->lock_states, ls_locks)
+			lock->ls_flags &= ~NFS_LOCK_INITIALIZED;
+		if (status >= 0) {
+			status = nfs4_reclaim_locks(ops, state);
+			if (status < 0)
+				goto out_err;
+			list_for_each_entry(lock, &state->lock_states, ls_locks) {
+				if (!(lock->ls_flags & NFS_LOCK_INITIALIZED))
+					printk("%s: Lock reclaim failed!\n",
+							__FUNCTION__);
+			}
+			continue;
+		}
+		switch (status) {
+			default:
+				printk(KERN_ERR "%s: unhandled error %d. Zeroing state\n",
+						__FUNCTION__, status);
+			case -ENOENT:
+			case -NFS4ERR_RECLAIM_BAD:
+			case -NFS4ERR_RECLAIM_CONFLICT:
+				/*
+				 * Open state on this file cannot be recovered
+				 * All we can do is revert to using the zero stateid.
+				 */
+				memset(state->stateid.data, 0,
+					sizeof(state->stateid.data));
+				/* Mark the file as being 'closed' */
+				state->state = 0;
+				break;
+			case -NFS4ERR_EXPIRED:
+			case -NFS4ERR_NO_GRACE:
+			case -NFS4ERR_STALE_CLIENTID:
+				goto out_err;
+		}
+	}
+	return 0;
+out_err:
+	return status;
+}
+
+static int reclaimer(void *ptr)
+{
+	struct reclaimer_args *args = (struct reclaimer_args *)ptr;
+	struct nfs4_client *clp = args->clp;
+	struct nfs4_state_owner *sp;
+	struct nfs4_state_recovery_ops *ops;
+	int status = 0;
+
+	daemonize("%u.%u.%u.%u-reclaim", NIPQUAD(clp->cl_addr));
+	allow_signal(SIGKILL);
+
+	atomic_inc(&clp->cl_count);
+	complete(&args->complete);
+
+	/* Ensure exclusive access to NFSv4 state */
+	lock_kernel();
+	down_write(&clp->cl_sem);
+	/* Are there any NFS mounts out there? */
+	if (list_empty(&clp->cl_superblocks))
+		goto out;
+restart_loop:
+	status = nfs4_proc_renew(clp);
+	switch (status) {
+		case 0:
+		case -NFS4ERR_CB_PATH_DOWN:
+			goto out;
+		case -NFS4ERR_STALE_CLIENTID:
+		case -NFS4ERR_LEASE_MOVED:
+			ops = &nfs4_reboot_recovery_ops;
+			break;
+		default:
+			ops = &nfs4_network_partition_recovery_ops;
+	};
+	status = __nfs4_init_client(clp);
+	if (status)
+		goto out_error;
+	/* Mark all delegations for reclaim */
+	nfs_delegation_mark_reclaim(clp);
+	/* Note: list is protected by exclusive lock on cl->cl_sem */
+	list_for_each_entry(sp, &clp->cl_state_owners, so_list) {
+		status = nfs4_reclaim_open_state(ops, sp);
+		if (status < 0) {
+			if (status == -NFS4ERR_NO_GRACE) {
+				ops = &nfs4_network_partition_recovery_ops;
+				status = nfs4_reclaim_open_state(ops, sp);
+			}
+			if (status == -NFS4ERR_STALE_CLIENTID)
+				goto restart_loop;
+			if (status == -NFS4ERR_EXPIRED)
+				goto restart_loop;
+		}
+	}
+	nfs_delegation_reap_unclaimed(clp);
+out:
+	set_bit(NFS4CLNT_OK, &clp->cl_state);
+	up_write(&clp->cl_sem);
+	unlock_kernel();
+	wake_up_all(&clp->cl_waitq);
+	rpc_wake_up(&clp->cl_rpcwaitq);
+	if (status == -NFS4ERR_CB_PATH_DOWN)
+		nfs_handle_cb_pathdown(clp);
+	nfs4_put_client(clp);
+	return 0;
+out_error:
+	printk(KERN_WARNING "Error: state recovery failed on NFSv4 server %u.%u.%u.%u with error %d\n",
+				NIPQUAD(clp->cl_addr.s_addr), -status);
+	goto out;
+}
+
+/*
+ * Local variables:
+ *  c-basic-offset: 8
+ * End:
+ */