[net-next-2.6.git] / fs / nfs / delegation.c

/*
 * linux/fs/nfs/delegation.c
 *
 * Copyright (C) 2004 Trond Myklebust
 *
 * NFS file delegation management
 *
 */
#include <linux/completion.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/spinlock.h>

#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_xdr.h>

#include "nfs4_fs.h"
#include "delegation.h"
#include "internal.h"

static void nfs_free_delegation(struct nfs_delegation *delegation)
{
	if (delegation->cred)
		put_rpccred(delegation->cred);
	kfree(delegation);
}

static void nfs_free_delegation_callback(struct rcu_head *head)
{
	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);

	nfs_free_delegation(delegation);
}

static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
{
	struct inode *inode = state->inode;
	struct file_lock *fl;
	int status;

	for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
		if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
			continue;
		if ((struct nfs_open_context *)fl->fl_file->private_data != ctx)
			continue;
		status = nfs4_lock_delegation_recall(state, fl);
		if (status >= 0)
			continue;
		switch (status) {
			default:
				printk(KERN_ERR "%s: unhandled error %d.\n",
						__FUNCTION__, status);
			case -NFS4ERR_EXPIRED:
				/* kill_proc(fl->fl_pid, SIGLOST, 1); */
			case -NFS4ERR_STALE_CLIENTID:
				nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs_client);
				goto out_err;
		}
	}
	return 0;
out_err:
	return status;
}

static void nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_open_context *ctx;
	struct nfs4_state *state;
	int err;

again:
	spin_lock(&inode->i_lock);
	list_for_each_entry(ctx, &nfsi->open_files, list) {
		state = ctx->state;
		if (state == NULL)
			continue;
		if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
			continue;
		if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
			continue;
		get_nfs_open_context(ctx);
		spin_unlock(&inode->i_lock);
		err = nfs4_open_delegation_recall(ctx, state, stateid);
		if (err >= 0)
			err = nfs_delegation_claim_locks(ctx, state);
		put_nfs_open_context(ctx);
		if (err != 0)
			return;
		goto again;
	}
	spin_unlock(&inode->i_lock);
}

/*
 * Set up a delegation on an inode
 */
void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
{
	struct nfs_delegation *delegation = NFS_I(inode)->delegation;

	if (delegation == NULL)
		return;
	memcpy(delegation->stateid.data, res->delegation.data,
			sizeof(delegation->stateid.data));
	delegation->type = res->delegation_type;
	delegation->maxsize = res->maxsize;
	put_rpccred(cred);
	delegation->cred = get_rpccred(cred);
	delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
	NFS_I(inode)->delegation_state = delegation->type;
	smp_wmb();
}

/*
 * Set up a delegation on an inode
 */
int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
{
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_delegation *delegation;
	int status = 0;

	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
	if (delegation == NULL)
		return -ENOMEM;
	memcpy(delegation->stateid.data, res->delegation.data,
			sizeof(delegation->stateid.data));
	delegation->type = res->delegation_type;
	delegation->maxsize = res->maxsize;
	delegation->change_attr = nfsi->change_attr;
	delegation->cred = get_rpccred(cred);
	delegation->inode = inode;

	spin_lock(&clp->cl_lock);
	if (rcu_dereference(nfsi->delegation) == NULL) {
		list_add_rcu(&delegation->super_list, &clp->cl_delegations);
		nfsi->delegation_state = delegation->type;
		rcu_assign_pointer(nfsi->delegation, delegation);
		delegation = NULL;
	} else {
		if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
					sizeof(delegation->stateid)) != 0 ||
				delegation->type != nfsi->delegation->type) {
			printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
					__FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
			status = -EIO;
		}
	}

	/* Ensure we revalidate the attributes and page cache! */
	spin_lock(&inode->i_lock);
	nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
	spin_unlock(&inode->i_lock);

	spin_unlock(&clp->cl_lock);
	kfree(delegation);
	return status;
}

static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
{
	int res = 0;

	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	return res;
}

/* Sync all data to disk upon delegation return */
static void nfs_msync_inode(struct inode *inode)
{
	filemap_fdatawrite(inode->i_mapping);
	nfs_wb_all(inode);
	filemap_fdatawait(inode->i_mapping);
}

/*
 * Basic procedure for returning a delegation to the server
 */
static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
{
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	struct nfs_inode *nfsi = NFS_I(inode);

	nfs_msync_inode(inode);
	down_read(&clp->cl_sem);
	/* Guard against new delegated open calls */
	down_write(&nfsi->rwsem);
	nfs_delegation_claim_opens(inode, &delegation->stateid);
	up_write(&nfsi->rwsem);
	up_read(&clp->cl_sem);
	nfs_msync_inode(inode);

	return nfs_do_return_delegation(inode, delegation);
}

static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
{
	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);

	if (delegation == NULL)
		goto nomatch;
	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
				sizeof(delegation->stateid.data)) != 0)
		goto nomatch;
	list_del_rcu(&delegation->super_list);
	nfsi->delegation_state = 0;
	rcu_assign_pointer(nfsi->delegation, NULL);
	return delegation;
nomatch:
	return NULL;
}

int nfs_inode_return_delegation(struct inode *inode)
{
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_delegation *delegation;
	int err = 0;

	if (rcu_dereference(nfsi->delegation) != NULL) {
		spin_lock(&clp->cl_lock);
		delegation = nfs_detach_delegation_locked(nfsi, NULL);
		spin_unlock(&clp->cl_lock);
		if (delegation != NULL)
			err = __nfs_inode_return_delegation(inode, delegation);
	}
	return err;
}

/*
 * Return all delegations associated to a super block
 */
void nfs_return_all_delegations(struct super_block *sb)
{
	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
	struct nfs_delegation *delegation;
	struct inode *inode;

	if (clp == NULL)
		return;
restart:
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		if (delegation->inode->i_sb != sb)
			continue;
		inode = igrab(delegation->inode);
		if (inode == NULL)
			continue;
		spin_lock(&clp->cl_lock);
		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
		spin_unlock(&clp->cl_lock);
		rcu_read_unlock();
		if (delegation != NULL)
			__nfs_inode_return_delegation(inode, delegation);
		iput(inode);
		goto restart;
	}
	rcu_read_unlock();
}

static int nfs_do_expire_all_delegations(void *ptr)
{
	struct nfs_client *clp = ptr;
	struct nfs_delegation *delegation;
	struct inode *inode;

	allow_signal(SIGKILL);
restart:
	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
		goto out;
	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
		goto out;
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		inode = igrab(delegation->inode);
		if (inode == NULL)
			continue;
		spin_lock(&clp->cl_lock);
		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
		spin_unlock(&clp->cl_lock);
		rcu_read_unlock();
		if (delegation)
			__nfs_inode_return_delegation(inode, delegation);
		iput(inode);
		goto restart;
	}
	rcu_read_unlock();
out:
	nfs_put_client(clp);
	module_put_and_exit(0);
}

void nfs_expire_all_delegations(struct nfs_client *clp)
{
	struct task_struct *task;

	__module_get(THIS_MODULE);
	atomic_inc(&clp->cl_count);
	task = kthread_run(nfs_do_expire_all_delegations, clp,
			"%u.%u.%u.%u-delegreturn",
			NIPQUAD(clp->cl_addr.sin_addr));
	if (!IS_ERR(task))
		return;
	nfs_put_client(clp);
	module_put(THIS_MODULE);
}

/*
 * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 */
void nfs_handle_cb_pathdown(struct nfs_client *clp)
{
	struct nfs_delegation *delegation;
	struct inode *inode;

	if (clp == NULL)
		return;
restart:
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		inode = igrab(delegation->inode);
		if (inode == NULL)
			continue;
		spin_lock(&clp->cl_lock);
		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
		spin_unlock(&clp->cl_lock);
		rcu_read_unlock();
		if (delegation != NULL)
			__nfs_inode_return_delegation(inode, delegation);
		iput(inode);
		goto restart;
	}
	rcu_read_unlock();
}

struct recall_threadargs {
	struct inode *inode;
	struct nfs_client *clp;
	const nfs4_stateid *stateid;

	struct completion started;
	int result;
};

static int recall_thread(void *data)
{
	struct recall_threadargs *args = (struct recall_threadargs *)data;
	struct inode *inode = igrab(args->inode);
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_delegation *delegation;

	daemonize("nfsv4-delegreturn");

	nfs_msync_inode(inode);
	down_read(&clp->cl_sem);
	down_write(&nfsi->rwsem);
	spin_lock(&clp->cl_lock);
	delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
	if (delegation != NULL)
		args->result = 0;
	else
		args->result = -ENOENT;
	spin_unlock(&clp->cl_lock);
	complete(&args->started);
	nfs_delegation_claim_opens(inode, args->stateid);
	up_write(&nfsi->rwsem);
	up_read(&clp->cl_sem);
	nfs_msync_inode(inode);

	if (delegation != NULL)
		nfs_do_return_delegation(inode, delegation);
	iput(inode);
	module_put_and_exit(0);
}

/*
 * Asynchronous delegation recall!
 */
int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
{
	struct recall_threadargs data = {
		.inode = inode,
		.stateid = stateid,
	};
	int status;

	init_completion(&data.started);
	__module_get(THIS_MODULE);
	status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
	if (status < 0)
		goto out_module_put;
	wait_for_completion(&data.started);
	return data.result;
out_module_put:
	module_put(THIS_MODULE);
	return status;
}

/*
 * Retrieve the inode associated with a delegation
 */
struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
{
	struct nfs_delegation *delegation;
	struct inode *res = NULL;
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
			res = igrab(delegation->inode);
			break;
		}
	}
	rcu_read_unlock();
	return res;
}

/*
 * Mark all delegations as needing to be reclaimed
 */
void nfs_delegation_mark_reclaim(struct nfs_client *clp)
{
	struct nfs_delegation *delegation;
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
		delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
	rcu_read_unlock();
}

/*
 * Reap all unclaimed delegations after reboot recovery is done
 */
void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
{
	struct nfs_delegation *delegation;
restart:
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
			continue;
		spin_lock(&clp->cl_lock);
		delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
		spin_unlock(&clp->cl_lock);
		rcu_read_unlock();
		if (delegation != NULL)
			call_rcu(&delegation->rcu, nfs_free_delegation_callback);
		goto restart;
	}
	rcu_read_unlock();
}

int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_delegation *delegation;
	int ret = 0;

	rcu_read_lock();
	delegation = rcu_dereference(nfsi->delegation);
	if (delegation != NULL) {
		memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
		ret = 1;
	}
	rcu_read_unlock();
	return ret;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/nfs/delegation.c
	3	*
	4	* Copyright (C) 2004 Trond Myklebust
	5	*
	6	* NFS file delegation management
	7	*
	8	*/
1da177e4	9	#include <linux/completion.h>
58d9714a	10	#include <linux/kthread.h>
1da177e4 LT	11	#include <linux/module.h>
	12	#include <linux/sched.h>
	13	#include <linux/spinlock.h>
	14
	15	#include <linux/nfs4.h>
	16	#include <linux/nfs_fs.h>
	17	#include <linux/nfs_xdr.h>
	18
4ce79717	19	#include "nfs4_fs.h"
1da177e4	20	#include "delegation.h"
24c8dbbb	21	#include "internal.h"
1da177e4	22
1da177e4 LT	23	static void nfs_free_delegation(struct nfs_delegation *delegation)
	24	{
	25	if (delegation->cred)
	26	put_rpccred(delegation->cred);
	27	kfree(delegation);
	28	}
	29
8383e460 TM	30	static void nfs_free_delegation_callback(struct rcu_head *head)
	31	{
	32	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
	33
	34	nfs_free_delegation(delegation);
	35	}
	36
888e694c TM	37	static int nfs_delegation_claim_locks(struct nfs_open_context ctx, struct nfs4_state state)
	38	{
	39	struct inode *inode = state->inode;
	40	struct file_lock *fl;
	41	int status;
	42
	43	for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
	44	if (!(fl->fl_flags & (FL_POSIX\|FL_FLOCK)))
	45	continue;
	46	if ((struct nfs_open_context *)fl->fl_file->private_data != ctx)
	47	continue;
	48	status = nfs4_lock_delegation_recall(state, fl);
	49	if (status >= 0)
	50	continue;
	51	switch (status) {
	52	default:
	53	printk(KERN_ERR "%s: unhandled error %d.\n",
	54	__FUNCTION__, status);
	55	case -NFS4ERR_EXPIRED:
	56	/* kill_proc(fl->fl_pid, SIGLOST, 1); */
	57	case -NFS4ERR_STALE_CLIENTID:
7539bbab	58	nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs_client);
888e694c TM	59	goto out_err;
	60	}
	61	}
	62	return 0;
	63	out_err:
	64	return status;
	65	}
	66
90163027	67	static void nfs_delegation_claim_opens(struct inode inode, const nfs4_stateid stateid)
1da177e4 LT	68	{
	69	struct nfs_inode *nfsi = NFS_I(inode);
	70	struct nfs_open_context *ctx;
	71	struct nfs4_state *state;
888e694c	72	int err;
1da177e4 LT	73
	74	again:
	75	spin_lock(&inode->i_lock);
	76	list_for_each_entry(ctx, &nfsi->open_files, list) {
	77	state = ctx->state;
	78	if (state == NULL)
	79	continue;
	80	if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
	81	continue;
90163027 TM	82	if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
90163027 TM	83	continue;
1da177e4 LT	84	get_nfs_open_context(ctx);
1da177e4 LT	85	spin_unlock(&inode->i_lock);
13437e12	86	err = nfs4_open_delegation_recall(ctx, state, stateid);
888e694c TM	87	if (err >= 0)
888e694c TM	88	err = nfs_delegation_claim_locks(ctx, state);
1da177e4	89	put_nfs_open_context(ctx);
888e694c TM	90	if (err != 0)
888e694c TM	91	return;
1da177e4 LT	92	goto again;
	93	}
	94	spin_unlock(&inode->i_lock);
	95	}
	96
	97	/*
	98	* Set up a delegation on an inode
	99	*/
	100	void nfs_inode_reclaim_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	101	{
	102	struct nfs_delegation *delegation = NFS_I(inode)->delegation;
	103
	104	if (delegation == NULL)
	105	return;
	106	memcpy(delegation->stateid.data, res->delegation.data,
	107	sizeof(delegation->stateid.data));
	108	delegation->type = res->delegation_type;
	109	delegation->maxsize = res->maxsize;
	110	put_rpccred(cred);
	111	delegation->cred = get_rpccred(cred);
	112	delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
	113	NFS_I(inode)->delegation_state = delegation->type;
	114	smp_wmb();
	115	}
	116
	117	/*
	118	* Set up a delegation on an inode
	119	*/
	120	int nfs_inode_set_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	121	{
7539bbab	122	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	123	struct nfs_inode *nfsi = NFS_I(inode);
	124	struct nfs_delegation *delegation;
	125	int status = 0;
	126
f52720ca	127	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
1da177e4 LT	128	if (delegation == NULL)
	129	return -ENOMEM;
	130	memcpy(delegation->stateid.data, res->delegation.data,
	131	sizeof(delegation->stateid.data));
	132	delegation->type = res->delegation_type;
	133	delegation->maxsize = res->maxsize;
beb2a5ec	134	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	135	delegation->cred = get_rpccred(cred);
	136	delegation->inode = inode;
	137
	138	spin_lock(&clp->cl_lock);
8383e460 TM	139	if (rcu_dereference(nfsi->delegation) == NULL) {
8383e460 TM	140	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
1da177e4	141	nfsi->delegation_state = delegation->type;
8383e460	142	rcu_assign_pointer(nfsi->delegation, delegation);
1da177e4 LT	143	delegation = NULL;
	144	} else {
	145	if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
	146	sizeof(delegation->stateid)) != 0 \|\|
	147	delegation->type != nfsi->delegation->type) {
	148	printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
24c8dbbb	149	__FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
1da177e4 LT	150	status = -EIO;
	151	}
	152	}
412c77ce TM	153
	154	/* Ensure we revalidate the attributes and page cache! */
	155	spin_lock(&inode->i_lock);
	156	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	157	spin_unlock(&inode->i_lock);
	158
1da177e4	159	spin_unlock(&clp->cl_lock);
f99d49ad	160	kfree(delegation);
1da177e4 LT	161	return status;
	162	}
	163
	164	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation)
	165	{
	166	int res = 0;
	167
1da177e4	168	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
8383e460	169	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
1da177e4 LT	170	return res;
	171	}
	172
	173	/* Sync all data to disk upon delegation return */
	174	static void nfs_msync_inode(struct inode *inode)
	175	{
	176	filemap_fdatawrite(inode->i_mapping);
	177	nfs_wb_all(inode);
	178	filemap_fdatawait(inode->i_mapping);
	179	}
	180
	181	/*
	182	* Basic procedure for returning a delegation to the server
	183	*/
90163027	184	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation)
1da177e4	185	{
7539bbab	186	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4	187	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	188
	189	nfs_msync_inode(inode);
	190	down_read(&clp->cl_sem);
	191	/* Guard against new delegated open calls */
	192	down_write(&nfsi->rwsem);
90163027	193	nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4 LT	194	up_write(&nfsi->rwsem);
	195	up_read(&clp->cl_sem);
	196	nfs_msync_inode(inode);
	197
90163027 TM	198	return nfs_do_return_delegation(inode, delegation);
	199	}
	200
	201	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	202	{
8383e460	203	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
90163027 TM	204
	205	if (delegation == NULL)
	206	goto nomatch;
	207	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
	208	sizeof(delegation->stateid.data)) != 0)
	209	goto nomatch;
8383e460	210	list_del_rcu(&delegation->super_list);
90163027	211	nfsi->delegation_state = 0;
8383e460	212	rcu_assign_pointer(nfsi->delegation, NULL);
90163027 TM	213	return delegation;
	214	nomatch:
	215	return NULL;
	216	}
	217
	218	int nfs_inode_return_delegation(struct inode *inode)
	219	{
	220	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	221	struct nfs_inode *nfsi = NFS_I(inode);
	222	struct nfs_delegation *delegation;
	223	int err = 0;
	224
8383e460	225	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	226	spin_lock(&clp->cl_lock);
	227	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	228	spin_unlock(&clp->cl_lock);
	229	if (delegation != NULL)
	230	err = __nfs_inode_return_delegation(inode, delegation);
	231	}
	232	return err;
1da177e4 LT	233	}
	234
	235	/*
	236	* Return all delegations associated to a super block
	237	*/
	238	void nfs_return_all_delegations(struct super_block *sb)
	239	{
7539bbab	240	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4 LT	241	struct nfs_delegation *delegation;
	242	struct inode *inode;
	243
	244	if (clp == NULL)
	245	return;
	246	restart:
8383e460 TM	247	rcu_read_lock();
8383e460 TM	248	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	249	if (delegation->inode->i_sb != sb)
	250	continue;
	251	inode = igrab(delegation->inode);
	252	if (inode == NULL)
	253	continue;
8383e460 TM	254	spin_lock(&clp->cl_lock);
8383e460 TM	255	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	256	spin_unlock(&clp->cl_lock);
8383e460 TM	257	rcu_read_unlock();
	258	if (delegation != NULL)
	259	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	260	iput(inode);
	261	goto restart;
	262	}
8383e460	263	rcu_read_unlock();
1da177e4 LT	264	}
1da177e4 LT	265
10afec90	266	static int nfs_do_expire_all_delegations(void *ptr)
58d9714a	267	{
adfa6f98	268	struct nfs_client *clp = ptr;
58d9714a TM	269	struct nfs_delegation *delegation;
58d9714a TM	270	struct inode *inode;
58d9714a TM	271
	272	allow_signal(SIGKILL);
	273	restart:
58d9714a TM	274	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
	275	goto out;
	276	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
	277	goto out;
8383e460 TM	278	rcu_read_lock();
8383e460 TM	279	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
58d9714a TM	280	inode = igrab(delegation->inode);
	281	if (inode == NULL)
	282	continue;
8383e460 TM	283	spin_lock(&clp->cl_lock);
8383e460 TM	284	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
58d9714a	285	spin_unlock(&clp->cl_lock);
8383e460 TM	286	rcu_read_unlock();
	287	if (delegation)
	288	__nfs_inode_return_delegation(inode, delegation);
58d9714a	289	iput(inode);
26c78e15	290	goto restart;
58d9714a	291	}
8383e460	292	rcu_read_unlock();
58d9714a	293	out:
24c8dbbb	294	nfs_put_client(clp);
58d9714a TM	295	module_put_and_exit(0);
	296	}
	297
adfa6f98	298	void nfs_expire_all_delegations(struct nfs_client *clp)
58d9714a TM	299	{
	300	struct task_struct *task;
	301
	302	__module_get(THIS_MODULE);
	303	atomic_inc(&clp->cl_count);
	304	task = kthread_run(nfs_do_expire_all_delegations, clp,
	305	"%u.%u.%u.%u-delegreturn",
24c8dbbb	306	NIPQUAD(clp->cl_addr.sin_addr));
58d9714a TM	307	if (!IS_ERR(task))
58d9714a TM	308	return;
24c8dbbb	309	nfs_put_client(clp);
58d9714a TM	310	module_put(THIS_MODULE);
	311	}
	312
1da177e4 LT	313	/*
	314	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	315	*/
adfa6f98	316	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4 LT	317	{
	318	struct nfs_delegation *delegation;
	319	struct inode *inode;
	320
	321	if (clp == NULL)
	322	return;
	323	restart:
8383e460 TM	324	rcu_read_lock();
8383e460 TM	325	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	326	inode = igrab(delegation->inode);
	327	if (inode == NULL)
	328	continue;
8383e460 TM	329	spin_lock(&clp->cl_lock);
8383e460 TM	330	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	331	spin_unlock(&clp->cl_lock);
8383e460 TM	332	rcu_read_unlock();
	333	if (delegation != NULL)
	334	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	335	iput(inode);
	336	goto restart;
	337	}
8383e460	338	rcu_read_unlock();
1da177e4 LT	339	}
	340
	341	struct recall_threadargs {
	342	struct inode *inode;
adfa6f98	343	struct nfs_client *clp;
1da177e4 LT	344	const nfs4_stateid *stateid;
	345
	346	struct completion started;
	347	int result;
	348	};
	349
	350	static int recall_thread(void *data)
	351	{
	352	struct recall_threadargs args = (struct recall_threadargs )data;
	353	struct inode *inode = igrab(args->inode);
7539bbab	354	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	355	struct nfs_inode *nfsi = NFS_I(inode);
	356	struct nfs_delegation *delegation;
	357
	358	daemonize("nfsv4-delegreturn");
	359
	360	nfs_msync_inode(inode);
	361	down_read(&clp->cl_sem);
	362	down_write(&nfsi->rwsem);
	363	spin_lock(&clp->cl_lock);
90163027 TM	364	delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
90163027 TM	365	if (delegation != NULL)
1da177e4	366	args->result = 0;
90163027	367	else
1da177e4	368	args->result = -ENOENT;
1da177e4 LT	369	spin_unlock(&clp->cl_lock);
1da177e4 LT	370	complete(&args->started);
90163027	371	nfs_delegation_claim_opens(inode, args->stateid);
1da177e4 LT	372	up_write(&nfsi->rwsem);
	373	up_read(&clp->cl_sem);
	374	nfs_msync_inode(inode);
	375
	376	if (delegation != NULL)
	377	nfs_do_return_delegation(inode, delegation);
	378	iput(inode);
	379	module_put_and_exit(0);
	380	}
	381
	382	/*
	383	* Asynchronous delegation recall!
	384	*/
	385	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
	386	{
	387	struct recall_threadargs data = {
	388	.inode = inode,
	389	.stateid = stateid,
	390	};
	391	int status;
	392
	393	init_completion(&data.started);
	394	__module_get(THIS_MODULE);
	395	status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
	396	if (status < 0)
	397	goto out_module_put;
	398	wait_for_completion(&data.started);
	399	return data.result;
	400	out_module_put:
	401	module_put(THIS_MODULE);
	402	return status;
	403	}
	404
	405	/*
	406	* Retrieve the inode associated with a delegation
	407	*/
adfa6f98	408	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	409	{
	410	struct nfs_delegation *delegation;
	411	struct inode *res = NULL;
8383e460 TM	412	rcu_read_lock();
8383e460 TM	413	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	414	if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
	415	res = igrab(delegation->inode);
	416	break;
	417	}
	418	}
8383e460	419	rcu_read_unlock();
1da177e4 LT	420	return res;
	421	}
	422
	423	/*
	424	* Mark all delegations as needing to be reclaimed
	425	*/
adfa6f98	426	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	427	{
1da177e4 LT	428	struct nfs_delegation *delegation;
8383e460 TM	429	rcu_read_lock();
8383e460 TM	430	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
1da177e4	431	delegation->flags \|= NFS_DELEGATION_NEED_RECLAIM;
8383e460	432	rcu_read_unlock();
1da177e4 LT	433	}
	434
	435	/*
	436	* Reap all unclaimed delegations after reboot recovery is done
	437	*/
adfa6f98	438	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	439	{
8383e460 TM	440	struct nfs_delegation *delegation;
	441	restart:
	442	rcu_read_lock();
	443	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	444	if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
1da177e4 LT	445	continue;
8383e460 TM	446	spin_lock(&clp->cl_lock);
	447	delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
	448	spin_unlock(&clp->cl_lock);
	449	rcu_read_unlock();
	450	if (delegation != NULL)
	451	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	452	goto restart;
1da177e4	453	}
8383e460	454	rcu_read_unlock();
1da177e4	455	}
3e4f6290 TM	456
	457	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	458	{
3e4f6290 TM	459	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	460	struct nfs_delegation *delegation;
8383e460	461	int ret = 0;
3e4f6290	462
8383e460 TM	463	rcu_read_lock();
8383e460 TM	464	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	465	if (delegation != NULL) {
3e4f6290 TM	466	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	467	ret = 1;
3e4f6290	468	}
8383e460 TM	469	rcu_read_unlock();
8383e460 TM	470	return ret;
3e4f6290	471	}