Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 1019 insertions, 0 deletions

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
new file mode 100644
index 0000000..401ef8b
--- /dev/null
+++ b/fs/nfs/nfs4state.c
@@ -0,0 +1,1019 @@
+/*
+ *  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/kernel.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_idmap.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/workqueue.h>
+#include <linux/bitops.h>
+
+#include "nfs4_fs.h"
+#include "callback.h"
+#include "delegation.h"
+#include "internal.h"
+
+#define OPENOWNER_POOL_SIZE	8
+
+const nfs4_stateid zero_stateid;
+
+static LIST_HEAD(nfs4_clientid_list);
+
+static int nfs4_init_client(struct nfs_client *clp, struct rpc_cred *cred)
+{
+	int status = nfs4_proc_setclientid(clp, NFS4_CALLBACK,
+			nfs_callback_tcpport, cred);
+	if (status == 0)
+		status = nfs4_proc_setclientid_confirm(clp, cred);
+	if (status == 0)
+		nfs4_schedule_state_renewal(clp);
+	return status;
+}
+
+static struct rpc_cred *nfs4_get_machine_cred(struct nfs_client *clp)
+{
+	struct rpc_cred *cred = NULL;
+
+	spin_lock(&clp->cl_lock);
+	if (clp->cl_machine_cred != NULL)
+		cred = get_rpccred(clp->cl_machine_cred);
+	spin_unlock(&clp->cl_lock);
+	return cred;
+}
+
+static void nfs4_clear_machine_cred(struct nfs_client *clp)
+{
+	struct rpc_cred *cred;
+
+	spin_lock(&clp->cl_lock);
+	cred = clp->cl_machine_cred;
+	clp->cl_machine_cred = NULL;
+	spin_unlock(&clp->cl_lock);
+	if (cred != NULL)
+		put_rpccred(cred);
+}
+
+struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp)
+{
+	struct nfs4_state_owner *sp;
+	struct rb_node *pos;
+	struct rpc_cred *cred = NULL;
+
+	for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) {
+		sp = rb_entry(pos, struct nfs4_state_owner, so_client_node);
+		if (list_empty(&sp->so_states))
+			continue;
+		cred = get_rpccred(sp->so_cred);
+		break;
+	}
+	return cred;
+}
+
+static struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp)
+{
+	struct nfs4_state_owner *sp;
+	struct rb_node *pos;
+	struct rpc_cred *cred;
+
+	cred = nfs4_get_machine_cred(clp);
+	if (cred != NULL)
+		goto out;
+	pos = rb_first(&clp->cl_state_owners);
+	if (pos != NULL) {
+		sp = rb_entry(pos, struct nfs4_state_owner, so_client_node);
+		cred = get_rpccred(sp->so_cred);
+	}
+out:
+	return cred;
+}
+
+static void nfs_alloc_unique_id(struct rb_root *root, struct nfs_unique_id *new,
+		__u64 minval, int maxbits)
+{
+	struct rb_node **p, *parent;
+	struct nfs_unique_id *pos;
+	__u64 mask = ~0ULL;
+
+	if (maxbits < 64)
+		mask = (1ULL << maxbits) - 1ULL;
+
+	/* Ensure distribution is more or less flat */
+	get_random_bytes(&new->id, sizeof(new->id));
+	new->id &= mask;
+	if (new->id < minval)
+		new->id += minval;
+retry:
+	p = &root->rb_node;
+	parent = NULL;
+
+	while (*p != NULL) {
+		parent = *p;
+		pos = rb_entry(parent, struct nfs_unique_id, rb_node);
+
+		if (new->id < pos->id)
+			p = &(*p)->rb_left;
+		else if (new->id > pos->id)
+			p = &(*p)->rb_right;
+		else
+			goto id_exists;
+	}
+	rb_link_node(&new->rb_node, parent, p);
+	rb_insert_color(&new->rb_node, root);
+	return;
+id_exists:
+	for (;;) {
+		new->id++;
+		if (new->id < minval || (new->id & mask) != new->id) {
+			new->id = minval;
+			break;
+		}
+		parent = rb_next(parent);
+		if (parent == NULL)
+			break;
+		pos = rb_entry(parent, struct nfs_unique_id, rb_node);
+		if (new->id < pos->id)
+			break;
+	}
+	goto retry;
+}
+
+static void nfs_free_unique_id(struct rb_root *root, struct nfs_unique_id *id)
+{
+	rb_erase(&id->rb_node, root);
+}
+
+static struct nfs4_state_owner *
+nfs4_find_state_owner(struct nfs_server *server, struct rpc_cred *cred)
+{
+	struct nfs_client *clp = server->nfs_client;
+	struct rb_node **p = &clp->cl_state_owners.rb_node,
+		       *parent = NULL;
+	struct nfs4_state_owner *sp, *res = NULL;
+
+	while (*p != NULL) {
+		parent = *p;
+		sp = rb_entry(parent, struct nfs4_state_owner, so_client_node);
+
+		if (server < sp->so_server) {
+			p = &parent->rb_left;
+			continue;
+		}
+		if (server > sp->so_server) {
+			p = &parent->rb_right;
+			continue;
+		}
+		if (cred < sp->so_cred)
+			p = &parent->rb_left;
+		else if (cred > sp->so_cred)
+			p = &parent->rb_right;
+		else {
+			atomic_inc(&sp->so_count);
+			res = sp;
+			break;
+		}
+	}
+	return res;
+}
+
+static struct nfs4_state_owner *
+nfs4_insert_state_owner(struct nfs_client *clp, struct nfs4_state_owner *new)
+{
+	struct rb_node **p = &clp->cl_state_owners.rb_node,
+		       *parent = NULL;
+	struct nfs4_state_owner *sp;
+
+	while (*p != NULL) {
+		parent = *p;
+		sp = rb_entry(parent, struct nfs4_state_owner, so_client_node);
+
+		if (new->so_server < sp->so_server) {
+			p = &parent->rb_left;
+			continue;
+		}
+		if (new->so_server > sp->so_server) {
+			p = &parent->rb_right;
+			continue;
+		}
+		if (new->so_cred < sp->so_cred)
+			p = &parent->rb_left;
+		else if (new->so_cred > sp->so_cred)
+			p = &parent->rb_right;
+		else {
+			atomic_inc(&sp->so_count);
+			return sp;
+		}
+	}
+	nfs_alloc_unique_id(&clp->cl_openowner_id, &new->so_owner_id, 1, 64);
+	rb_link_node(&new->so_client_node, parent, p);
+	rb_insert_color(&new->so_client_node, &clp->cl_state_owners);
+	return new;
+}
+
+static void
+nfs4_remove_state_owner(struct nfs_client *clp, struct nfs4_state_owner *sp)
+{
+	if (!RB_EMPTY_NODE(&sp->so_client_node))
+		rb_erase(&sp->so_client_node, &clp->cl_state_owners);
+	nfs_free_unique_id(&clp->cl_openowner_id, &sp->so_owner_id);
+}
+
+/*
+ * 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 = kzalloc(sizeof(*sp),GFP_KERNEL);
+	if (!sp)
+		return NULL;
+	spin_lock_init(&sp->so_lock);
+	INIT_LIST_HEAD(&sp->so_states);
+	INIT_LIST_HEAD(&sp->so_delegations);
+	rpc_init_wait_queue(&sp->so_sequence.wait, "Seqid_waitqueue");
+	sp->so_seqid.sequence = &sp->so_sequence;
+	spin_lock_init(&sp->so_sequence.lock);
+	INIT_LIST_HEAD(&sp->so_sequence.list);
+	atomic_set(&sp->so_count, 1);
+	return sp;
+}
+
+static void
+nfs4_drop_state_owner(struct nfs4_state_owner *sp)
+{
+	if (!RB_EMPTY_NODE(&sp->so_client_node)) {
+		struct nfs_client *clp = sp->so_client;
+
+		spin_lock(&clp->cl_lock);
+		rb_erase(&sp->so_client_node, &clp->cl_state_owners);
+		RB_CLEAR_NODE(&sp->so_client_node);
+		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 nfs_client *clp = server->nfs_client;
+	struct nfs4_state_owner *sp, *new;
+
+	spin_lock(&clp->cl_lock);
+	sp = nfs4_find_state_owner(server, cred);
+	spin_unlock(&clp->cl_lock);
+	if (sp != NULL)
+		return sp;
+	new = nfs4_alloc_state_owner();
+	if (new == NULL)
+		return NULL;
+	new->so_client = clp;
+	new->so_server = server;
+	new->so_cred = cred;
+	spin_lock(&clp->cl_lock);
+	sp = nfs4_insert_state_owner(clp, new);
+	spin_unlock(&clp->cl_lock);
+	if (sp == new)
+		get_rpccred(cred);
+	else {
+		rpc_destroy_wait_queue(&new->so_sequence.wait);
+		kfree(new);
+	}
+	return sp;
+}
+
+/*
+ * 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 nfs_client *clp = sp->so_client;
+	struct rpc_cred *cred = sp->so_cred;
+
+	if (!atomic_dec_and_lock(&sp->so_count, &clp->cl_lock))
+		return;
+	nfs4_remove_state_owner(clp, sp);
+	spin_unlock(&clp->cl_lock);
+	rpc_destroy_wait_queue(&sp->so_sequence.wait);
+	put_rpccred(cred);
+	kfree(sp);
+}
+
+static struct nfs4_state *
+nfs4_alloc_open_state(void)
+{
+	struct nfs4_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return NULL;
+	atomic_set(&state->count, 1);
+	INIT_LIST_HEAD(&state->lock_states);
+	spin_lock_init(&state->state_lock);
+	seqlock_init(&state->seqlock);
+	return state;
+}
+
+void
+nfs4_state_set_mode_locked(struct nfs4_state *state, mode_t mode)
+{
+	if (state->state == mode)
+		return;
+	/* NB! List reordering - see the reclaim code for why.  */
+	if ((mode & FMODE_WRITE) != (state->state & FMODE_WRITE)) {
+		if (mode & FMODE_WRITE)
+			list_move(&state->open_states, &state->owner->so_states);
+		else
+			list_move_tail(&state->open_states, &state->owner->so_states);
+	}
+	state->state = mode;
+}
+
+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) {
+		if (state->owner != owner)
+			continue;
+		if (atomic_inc_not_zero(&state->count))
+			return state;
+	}
+	return NULL;
+}
+
+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(&owner->so_lock);
+	spin_lock(&inode->i_lock);
+	state = __nfs4_find_state_byowner(inode, owner);
+	if (state == NULL && new != NULL) {
+		state = new;
+		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);
+		/* 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);
+		spin_unlock(&owner->so_lock);
+	} else {
+		spin_unlock(&inode->i_lock);
+		spin_unlock(&owner->so_lock);
+		if (new)
+			nfs4_free_open_state(new);
+	}
+out:
+	return state;
+}
+
+/*
+ * Beware! Caller must be holding exactly one
+ * reference to clp->cl_sem!
+ */
+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, &owner->so_lock))
+		return;
+	spin_lock(&inode->i_lock);
+	list_del(&state->inode_states);
+	list_del(&state->open_states);
+	spin_unlock(&inode->i_lock);
+	spin_unlock(&owner->so_lock);
+	iput(inode);
+	nfs4_free_open_state(state);
+	nfs4_put_state_owner(owner);
+}
+
+/*
+ * Close the current file.
+ */
+static void __nfs4_close(struct path *path, struct nfs4_state *state, mode_t mode, int wait)
+{
+	struct nfs4_state_owner *owner = state->owner;
+	int call_close = 0;
+	int newstate;
+
+	atomic_inc(&owner->so_count);
+	/* Protect against nfs4_find_state() */
+	spin_lock(&owner->so_lock);
+	switch (mode & (FMODE_READ | FMODE_WRITE)) {
+		case FMODE_READ:
+			state->n_rdonly--;
+			break;
+		case FMODE_WRITE:
+			state->n_wronly--;
+			break;
+		case FMODE_READ|FMODE_WRITE:
+			state->n_rdwr--;
+	}
+	newstate = FMODE_READ|FMODE_WRITE;
+	if (state->n_rdwr == 0) {
+		if (state->n_rdonly == 0) {
+			newstate &= ~FMODE_READ;
+			call_close |= test_bit(NFS_O_RDONLY_STATE, &state->flags);
+			call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
+		}
+		if (state->n_wronly == 0) {
+			newstate &= ~FMODE_WRITE;
+			call_close |= test_bit(NFS_O_WRONLY_STATE, &state->flags);
+			call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
+		}
+		if (newstate == 0)
+			clear_bit(NFS_DELEGATED_STATE, &state->flags);
+	}
+	nfs4_state_set_mode_locked(state, newstate);
+	spin_unlock(&owner->so_lock);
+
+	if (!call_close) {
+		nfs4_put_open_state(state);
+		nfs4_put_state_owner(owner);
+	} else
+		nfs4_do_close(path, state, wait);
+}
+
+void nfs4_close_state(struct path *path, struct nfs4_state *state, mode_t mode)
+{
+	__nfs4_close(path, state, mode, 0);
+}
+
+void nfs4_close_sync(struct path *path, struct nfs4_state *state, mode_t mode)
+{
+	__nfs4_close(path, state, mode, 1);
+}
+
+/*
+ * 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;
+}
+
+/*
+ * Return a compatible lock_state. If no initialized lock_state structure
+ * exists, return an uninitialized one.
+ *
+ */
+static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
+{
+	struct nfs4_lock_state *lsp;
+	struct nfs_client *clp = state->owner->so_client;
+
+	lsp = kzalloc(sizeof(*lsp), GFP_KERNEL);
+	if (lsp == NULL)
+		return NULL;
+	rpc_init_wait_queue(&lsp->ls_sequence.wait, "lock_seqid_waitqueue");
+	spin_lock_init(&lsp->ls_sequence.lock);
+	INIT_LIST_HEAD(&lsp->ls_sequence.list);
+	lsp->ls_seqid.sequence = &lsp->ls_sequence;
+	atomic_set(&lsp->ls_count, 1);
+	lsp->ls_owner = fl_owner;
+	spin_lock(&clp->cl_lock);
+	nfs_alloc_unique_id(&clp->cl_lockowner_id, &lsp->ls_id, 1, 64);
+	spin_unlock(&clp->cl_lock);
+	INIT_LIST_HEAD(&lsp->ls_locks);
+	return lsp;
+}
+
+static void nfs4_free_lock_state(struct nfs4_lock_state *lsp)
+{
+	struct nfs_client *clp = lsp->ls_state->owner->so_client;
+
+	spin_lock(&clp->cl_lock);
+	nfs_free_unique_id(&clp->cl_lockowner_id, &lsp->ls_id);
+	spin_unlock(&clp->cl_lock);
+	rpc_destroy_wait_queue(&lsp->ls_sequence.wait);
+	kfree(lsp);
+}
+
+/*
+ * Return a compatible lock_state. If no initialized lock_state structure
+ * exists, return an uninitialized one.
+ *
+ * The caller must be holding clp->cl_sem
+ */
+static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t owner)
+{
+	struct nfs4_lock_state *lsp, *new = NULL;
+	
+	for(;;) {
+		spin_lock(&state->state_lock);
+		lsp = __nfs4_find_lock_state(state, owner);
+		if (lsp != NULL)
+			break;
+		if (new != NULL) {
+			new->ls_state = state;
+			list_add(&new->ls_locks, &state->lock_states);
+			set_bit(LK_STATE_IN_USE, &state->flags);
+			lsp = new;
+			new = NULL;
+			break;
+		}
+		spin_unlock(&state->state_lock);
+		new = nfs4_alloc_lock_state(state, owner);
+		if (new == NULL)
+			return NULL;
+	}
+	spin_unlock(&state->state_lock);
+	if (new != NULL)
+		nfs4_free_lock_state(new);
+	return 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)
+{
+	struct nfs4_state *state;
+
+	if (lsp == NULL)
+		return;
+	state = lsp->ls_state;
+	if (!atomic_dec_and_lock(&lsp->ls_count, &state->state_lock))
+		return;
+	list_del(&lsp->ls_locks);
+	if (list_empty(&state->lock_states))
+		clear_bit(LK_STATE_IN_USE, &state->flags);
+	spin_unlock(&state->state_lock);
+	nfs4_free_lock_state(lsp);
+}
+
+static void nfs4_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
+{
+	struct nfs4_lock_state *lsp = src->fl_u.nfs4_fl.owner;
+
+	dst->fl_u.nfs4_fl.owner = lsp;
+	atomic_inc(&lsp->ls_count);
+}
+
+static void nfs4_fl_release_lock(struct file_lock *fl)
+{
+	nfs4_put_lock_state(fl->fl_u.nfs4_fl.owner);
+}
+
+static struct file_lock_operations nfs4_fl_lock_ops = {
+	.fl_copy_lock = nfs4_fl_copy_lock,
+	.fl_release_private = nfs4_fl_release_lock,
+};
+
+int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl)
+{
+	struct nfs4_lock_state *lsp;
+
+	if (fl->fl_ops != NULL)
+		return 0;
+	lsp = nfs4_get_lock_state(state, fl->fl_owner);
+	if (lsp == NULL)
+		return -ENOMEM;
+	fl->fl_u.nfs4_fl.owner = lsp;
+	fl->fl_ops = &nfs4_fl_lock_ops;
+	return 0;
+}
+
+/*
+ * 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)
+{
+	struct nfs4_lock_state *lsp;
+	int seq;
+
+	do {
+		seq = read_seqbegin(&state->seqlock);
+		memcpy(dst, &state->stateid, sizeof(*dst));
+	} while (read_seqretry(&state->seqlock, seq));
+	if (test_bit(LK_STATE_IN_USE, &state->flags) == 0)
+		return;
+
+	spin_lock(&state->state_lock);
+	lsp = __nfs4_find_lock_state(state, fl_owner);
+	if (lsp != NULL && (lsp->ls_flags & NFS_LOCK_INITIALIZED) != 0)
+		memcpy(dst, &lsp->ls_stateid, sizeof(*dst));
+	spin_unlock(&state->state_lock);
+	nfs4_put_lock_state(lsp);
+}
+
+struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter)
+{
+	struct nfs_seqid *new;
+
+	new = kmalloc(sizeof(*new), GFP_KERNEL);
+	if (new != NULL) {
+		new->sequence = counter;
+		INIT_LIST_HEAD(&new->list);
+	}
+	return new;
+}
+
+void nfs_free_seqid(struct nfs_seqid *seqid)
+{
+	if (!list_empty(&seqid->list)) {
+		struct rpc_sequence *sequence = seqid->sequence->sequence;
+
+		spin_lock(&sequence->lock);
+		list_del(&seqid->list);
+		spin_unlock(&sequence->lock);
+		rpc_wake_up(&sequence->wait);
+	}
+	kfree(seqid);
+}
+
+/*
+ * 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()
+ */
+static void nfs_increment_seqid(int status, struct nfs_seqid *seqid)
+{
+	BUG_ON(list_first_entry(&seqid->sequence->sequence->list, struct nfs_seqid, list) != seqid);
+	switch (status) {
+		case 0:
+			break;
+		case -NFS4ERR_BAD_SEQID:
+			if (seqid->sequence->flags & NFS_SEQID_CONFIRMED)
+				return;
+			printk(KERN_WARNING "NFS: v4 server returned a bad"
+					" sequence-id error on an"
+					" unconfirmed sequence %p!\n",
+					seqid->sequence);
+		case -NFS4ERR_STALE_CLIENTID:
+		case -NFS4ERR_STALE_STATEID:
+		case -NFS4ERR_BAD_STATEID:
+		case -NFS4ERR_BADXDR:
+		case -NFS4ERR_RESOURCE:
+		case -NFS4ERR_NOFILEHANDLE:
+			/* Non-seqid mutating errors */
+			return;
+	};
+	/*
+	 * Note: no locking needed as we are guaranteed to be first
+	 * on the sequence list
+	 */
+	seqid->sequence->counter++;
+}
+
+void nfs_increment_open_seqid(int status, struct nfs_seqid *seqid)
+{
+	if (status == -NFS4ERR_BAD_SEQID) {
+		struct nfs4_state_owner *sp = container_of(seqid->sequence,
+				struct nfs4_state_owner, so_seqid);
+		nfs4_drop_state_owner(sp);
+	}
+	nfs_increment_seqid(status, seqid);
+}
+
+/*
+ * Increment the seqid if the LOCK/LOCKU succeeded, or
+ * failed with a seqid incrementing error -
+ * see comments nfs_fs.h:seqid_mutating_error()
+ */
+void nfs_increment_lock_seqid(int status, struct nfs_seqid *seqid)
+{
+	nfs_increment_seqid(status, seqid);
+}
+
+int nfs_wait_on_sequence(struct nfs_seqid *seqid, struct rpc_task *task)
+{
+	struct rpc_sequence *sequence = seqid->sequence->sequence;
+	int status = 0;
+
+	spin_lock(&sequence->lock);
+	if (list_empty(&seqid->list))
+		list_add_tail(&seqid->list, &sequence->list);
+	if (list_first_entry(&sequence->list, struct nfs_seqid, list) == seqid)
+		goto unlock;
+	rpc_sleep_on(&sequence->wait, task, NULL);
+	status = -EAGAIN;
+unlock:
+	spin_unlock(&sequence->lock);
+	return status;
+}
+
+static int reclaimer(void *);
+
+static inline void nfs4_clear_recover_bit(struct nfs_client *clp)
+{
+	smp_mb__before_clear_bit();
+	clear_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state);
+	smp_mb__after_clear_bit();
+	wake_up_bit(&clp->cl_state, NFS4CLNT_STATE_RECOVER);
+	rpc_wake_up(&clp->cl_rpcwaitq);
+}
+
+/*
+ * State recovery routine
+ */
+static void nfs4_recover_state(struct nfs_client *clp)
+{
+	struct task_struct *task;
+
+	__module_get(THIS_MODULE);
+	atomic_inc(&clp->cl_count);
+	task = kthread_run(reclaimer, clp, "%s-reclaim",
+				rpc_peeraddr2str(clp->cl_rpcclient,
+							RPC_DISPLAY_ADDR));
+	if (!IS_ERR(task))
+		return;
+	nfs4_clear_recover_bit(clp);
+	nfs_put_client(clp);
+	module_put(THIS_MODULE);
+}
+
+/*
+ * Schedule a state recovery attempt
+ */
+void nfs4_schedule_state_recovery(struct nfs_client *clp)
+{
+	if (!clp)
+		return;
+	if (test_and_set_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) == 0)
+		nfs4_recover_state(clp);
+}
+
+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 != NULL; fl = fl->fl_next) {
+		if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
+			continue;
+		if (nfs_file_open_context(fl->fl_file)->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",
+						__func__, status);
+			case -NFS4ERR_EXPIRED:
+			case -NFS4ERR_NO_GRACE:
+			case -NFS4ERR_RECLAIM_BAD:
+			case -NFS4ERR_RECLAIM_CONFLICT:
+				/* kill_proc(fl->fl_pid, 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);
+		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",
+							__func__);
+			}
+			continue;
+		}
+		switch (status) {
+			default:
+				printk(KERN_ERR "%s: unhandled error %d. Zeroing state\n",
+						__func__, 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 void nfs4_state_mark_reclaim(struct nfs_client *clp)
+{
+	struct nfs4_state_owner *sp;
+	struct rb_node *pos;
+	struct nfs4_state *state;
+	struct nfs4_lock_state *lock;
+
+	/* Reset all sequence ids to zero */
+	for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) {
+		sp = rb_entry(pos, struct nfs4_state_owner, so_client_node);
+		sp->so_seqid.counter = 0;
+		sp->so_seqid.flags = 0;
+		spin_lock(&sp->so_lock);
+		list_for_each_entry(state, &sp->so_states, open_states) {
+			clear_bit(NFS_DELEGATED_STATE, &state->flags);
+			clear_bit(NFS_O_RDONLY_STATE, &state->flags);
+			clear_bit(NFS_O_WRONLY_STATE, &state->flags);
+			clear_bit(NFS_O_RDWR_STATE, &state->flags);
+			list_for_each_entry(lock, &state->lock_states, ls_locks) {
+				lock->ls_seqid.counter = 0;
+				lock->ls_seqid.flags = 0;
+				lock->ls_flags &= ~NFS_LOCK_INITIALIZED;
+			}
+		}
+		spin_unlock(&sp->so_lock);
+	}
+}
+
+static int reclaimer(void *ptr)
+{
+	struct nfs_client *clp = ptr;
+	struct nfs4_state_owner *sp;
+	struct rb_node *pos;
+	struct nfs4_state_recovery_ops *ops;
+	struct rpc_cred *cred;
+	int status = 0;
+
+	allow_signal(SIGKILL);
+
+	/* Ensure exclusive access to NFSv4 state */
+	down_write(&clp->cl_sem);
+	/* Are there any NFS mounts out there? */
+	if (list_empty(&clp->cl_superblocks))
+		goto out;
+restart_loop:
+	ops = &nfs4_network_partition_recovery_ops;
+	/* Are there any open files on this volume? */
+	cred = nfs4_get_renew_cred(clp);
+	if (cred != NULL) {
+		/* Yes there are: try to renew the old lease */
+		status = nfs4_proc_renew(clp, cred);
+		put_rpccred(cred);
+		switch (status) {
+			case 0:
+			case -NFS4ERR_CB_PATH_DOWN:
+				goto out;
+			case -NFS4ERR_STALE_CLIENTID:
+			case -NFS4ERR_LEASE_MOVED:
+				ops = &nfs4_reboot_recovery_ops;
+		}
+	} else {
+		/* "reboot" to ensure we clear all state on the server */
+		clp->cl_boot_time = CURRENT_TIME;
+	}
+	/* We're going to have to re-establish a clientid */
+	nfs4_state_mark_reclaim(clp);
+	status = -ENOENT;
+	cred = nfs4_get_setclientid_cred(clp);
+	if (cred != NULL) {
+		status = nfs4_init_client(clp, cred);
+		put_rpccred(cred);
+		/* Handle case where the user hasn't set up machine creds */
+		if (status == -EACCES && cred == clp->cl_machine_cred) {
+			nfs4_clear_machine_cred(clp);
+			goto restart_loop;
+		}
+	}
+	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 */
+	for (pos = rb_first(&clp->cl_state_owners); pos != NULL; pos = rb_next(pos)) {
+		sp = rb_entry(pos, struct nfs4_state_owner, so_client_node);
+		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:
+	up_write(&clp->cl_sem);
+	if (status == -NFS4ERR_CB_PATH_DOWN)
+		nfs_handle_cb_pathdown(clp);
+	nfs4_clear_recover_bit(clp);
+	nfs_put_client(clp);
+	module_put_and_exit(0);
+	return 0;
+out_error:
+	printk(KERN_WARNING "Error: state recovery failed on NFSv4 server %s"
+			" with error %d\n", clp->cl_hostname, -status);
+	set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
+	goto out;
+}
+
+/*
+ * Local variables:
+ *  c-basic-offset: 8
+ * End:
+ */