[linux.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_do_free_delegation(struct nfs_delegation *delegation)
{
	kfree(delegation);
}

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

	nfs_do_free_delegation(delegation);
}

static void nfs_free_delegation(struct nfs_delegation *delegation)
{
	struct rpc_cred *cred;

	cred = rcu_dereference(delegation->cred);
	rcu_assign_pointer(delegation->cred, NULL);
	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	if (cred)
		put_rpccred(cred);
}

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 (nfs_file_open_context(fl->fl_file) != 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;
	struct rpc_cred *oldcred;

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

/*
 * 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);
	if (delegation != NULL)
		nfs_free_delegation(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);
	nfs_free_delegation(delegation);
	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)
			nfs_free_delegation(delegation);
		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
905f8d16	23	static void nfs_do_free_delegation(struct nfs_delegation *delegation)
1da177e4	24	{
1da177e4 LT	25	kfree(delegation);
	26	}
	27
8383e460 TM	28	static void nfs_free_delegation_callback(struct rcu_head *head)
	29	{
	30	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
	31
905f8d16 TM	32	nfs_do_free_delegation(delegation);
	33	}
	34
	35	static void nfs_free_delegation(struct nfs_delegation *delegation)
	36	{
	37	struct rpc_cred *cred;
	38
	39	cred = rcu_dereference(delegation->cred);
	40	rcu_assign_pointer(delegation->cred, NULL);
	41	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	42	if (cred)
	43	put_rpccred(cred);
8383e460 TM	44	}
8383e460 TM	45
888e694c TM	46	static int nfs_delegation_claim_locks(struct nfs_open_context ctx, struct nfs4_state state)
	47	{
	48	struct inode *inode = state->inode;
	49	struct file_lock *fl;
	50	int status;
	51
	52	for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
	53	if (!(fl->fl_flags & (FL_POSIX\|FL_FLOCK)))
	54	continue;
cd3758e3	55	if (nfs_file_open_context(fl->fl_file) != ctx)
888e694c TM	56	continue;
	57	status = nfs4_lock_delegation_recall(state, fl);
	58	if (status >= 0)
	59	continue;
	60	switch (status) {
	61	default:
	62	printk(KERN_ERR "%s: unhandled error %d.\n",
	63	__FUNCTION__, status);
	64	case -NFS4ERR_EXPIRED:
	65	/* kill_proc(fl->fl_pid, SIGLOST, 1); */
	66	case -NFS4ERR_STALE_CLIENTID:
7539bbab	67	nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs_client);
888e694c TM	68	goto out_err;
	69	}
	70	}
	71	return 0;
	72	out_err:
	73	return status;
	74	}
	75
90163027	76	static void nfs_delegation_claim_opens(struct inode inode, const nfs4_stateid stateid)
1da177e4 LT	77	{
	78	struct nfs_inode *nfsi = NFS_I(inode);
	79	struct nfs_open_context *ctx;
	80	struct nfs4_state *state;
888e694c	81	int err;
1da177e4 LT	82
	83	again:
	84	spin_lock(&inode->i_lock);
	85	list_for_each_entry(ctx, &nfsi->open_files, list) {
	86	state = ctx->state;
	87	if (state == NULL)
	88	continue;
	89	if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
	90	continue;
90163027 TM	91	if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
90163027 TM	92	continue;
1da177e4 LT	93	get_nfs_open_context(ctx);
1da177e4 LT	94	spin_unlock(&inode->i_lock);
13437e12	95	err = nfs4_open_delegation_recall(ctx, state, stateid);
888e694c TM	96	if (err >= 0)
888e694c TM	97	err = nfs_delegation_claim_locks(ctx, state);
1da177e4	98	put_nfs_open_context(ctx);
888e694c TM	99	if (err != 0)
888e694c TM	100	return;
1da177e4 LT	101	goto again;
	102	}
	103	spin_unlock(&inode->i_lock);
	104	}
	105
	106	/*
	107	* Set up a delegation on an inode
	108	*/
	109	void nfs_inode_reclaim_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	110	{
	111	struct nfs_delegation *delegation = NFS_I(inode)->delegation;
05c88bab	112	struct rpc_cred *oldcred;
1da177e4 LT	113
	114	if (delegation == NULL)
	115	return;
	116	memcpy(delegation->stateid.data, res->delegation.data,
	117	sizeof(delegation->stateid.data));
	118	delegation->type = res->delegation_type;
	119	delegation->maxsize = res->maxsize;
05c88bab	120	oldcred = delegation->cred;
1da177e4 LT	121	delegation->cred = get_rpccred(cred);
	122	delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
	123	NFS_I(inode)->delegation_state = delegation->type;
	124	smp_wmb();
05c88bab	125	put_rpccred(oldcred);
1da177e4 LT	126	}
	127
	128	/*
	129	* Set up a delegation on an inode
	130	*/
	131	int nfs_inode_set_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	132	{
7539bbab	133	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	134	struct nfs_inode *nfsi = NFS_I(inode);
	135	struct nfs_delegation *delegation;
	136	int status = 0;
	137
f52720ca	138	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
1da177e4 LT	139	if (delegation == NULL)
	140	return -ENOMEM;
	141	memcpy(delegation->stateid.data, res->delegation.data,
	142	sizeof(delegation->stateid.data));
	143	delegation->type = res->delegation_type;
	144	delegation->maxsize = res->maxsize;
beb2a5ec	145	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	146	delegation->cred = get_rpccred(cred);
	147	delegation->inode = inode;
	148
	149	spin_lock(&clp->cl_lock);
8383e460 TM	150	if (rcu_dereference(nfsi->delegation) == NULL) {
8383e460 TM	151	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
1da177e4	152	nfsi->delegation_state = delegation->type;
8383e460	153	rcu_assign_pointer(nfsi->delegation, delegation);
1da177e4 LT	154	delegation = NULL;
	155	} else {
	156	if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
	157	sizeof(delegation->stateid)) != 0 \|\|
	158	delegation->type != nfsi->delegation->type) {
	159	printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
24c8dbbb	160	__FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
1da177e4 LT	161	status = -EIO;
	162	}
	163	}
412c77ce TM	164
	165	/* Ensure we revalidate the attributes and page cache! */
	166	spin_lock(&inode->i_lock);
	167	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	168	spin_unlock(&inode->i_lock);
	169
1da177e4	170	spin_unlock(&clp->cl_lock);
603c83da TM	171	if (delegation != NULL)
603c83da TM	172	nfs_free_delegation(delegation);
1da177e4 LT	173	return status;
	174	}
	175
	176	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation)
	177	{
	178	int res = 0;
	179
1da177e4	180	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
905f8d16	181	nfs_free_delegation(delegation);
1da177e4 LT	182	return res;
	183	}
	184
	185	/* Sync all data to disk upon delegation return */
	186	static void nfs_msync_inode(struct inode *inode)
	187	{
	188	filemap_fdatawrite(inode->i_mapping);
	189	nfs_wb_all(inode);
	190	filemap_fdatawait(inode->i_mapping);
	191	}
	192
	193	/*
	194	* Basic procedure for returning a delegation to the server
	195	*/
90163027	196	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation)
1da177e4	197	{
7539bbab	198	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4	199	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	200
	201	nfs_msync_inode(inode);
	202	down_read(&clp->cl_sem);
	203	/* Guard against new delegated open calls */
	204	down_write(&nfsi->rwsem);
90163027	205	nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4 LT	206	up_write(&nfsi->rwsem);
	207	up_read(&clp->cl_sem);
	208	nfs_msync_inode(inode);
	209
90163027 TM	210	return nfs_do_return_delegation(inode, delegation);
	211	}
	212
	213	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	214	{
8383e460	215	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
90163027 TM	216
	217	if (delegation == NULL)
	218	goto nomatch;
	219	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
	220	sizeof(delegation->stateid.data)) != 0)
	221	goto nomatch;
8383e460	222	list_del_rcu(&delegation->super_list);
90163027	223	nfsi->delegation_state = 0;
8383e460	224	rcu_assign_pointer(nfsi->delegation, NULL);
90163027 TM	225	return delegation;
	226	nomatch:
	227	return NULL;
	228	}
	229
	230	int nfs_inode_return_delegation(struct inode *inode)
	231	{
	232	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	233	struct nfs_inode *nfsi = NFS_I(inode);
	234	struct nfs_delegation *delegation;
	235	int err = 0;
	236
8383e460	237	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	238	spin_lock(&clp->cl_lock);
	239	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	240	spin_unlock(&clp->cl_lock);
	241	if (delegation != NULL)
	242	err = __nfs_inode_return_delegation(inode, delegation);
	243	}
	244	return err;
1da177e4 LT	245	}
	246
	247	/*
	248	* Return all delegations associated to a super block
	249	*/
	250	void nfs_return_all_delegations(struct super_block *sb)
	251	{
7539bbab	252	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4 LT	253	struct nfs_delegation *delegation;
	254	struct inode *inode;
	255
	256	if (clp == NULL)
	257	return;
	258	restart:
8383e460 TM	259	rcu_read_lock();
8383e460 TM	260	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	261	if (delegation->inode->i_sb != sb)
	262	continue;
	263	inode = igrab(delegation->inode);
	264	if (inode == NULL)
	265	continue;
8383e460 TM	266	spin_lock(&clp->cl_lock);
8383e460 TM	267	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	268	spin_unlock(&clp->cl_lock);
8383e460 TM	269	rcu_read_unlock();
	270	if (delegation != NULL)
	271	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	272	iput(inode);
	273	goto restart;
	274	}
8383e460	275	rcu_read_unlock();
1da177e4 LT	276	}
1da177e4 LT	277
10afec90	278	static int nfs_do_expire_all_delegations(void *ptr)
58d9714a	279	{
adfa6f98	280	struct nfs_client *clp = ptr;
58d9714a TM	281	struct nfs_delegation *delegation;
58d9714a TM	282	struct inode *inode;
58d9714a TM	283
	284	allow_signal(SIGKILL);
	285	restart:
58d9714a TM	286	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
	287	goto out;
	288	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
	289	goto out;
8383e460 TM	290	rcu_read_lock();
8383e460 TM	291	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
58d9714a TM	292	inode = igrab(delegation->inode);
	293	if (inode == NULL)
	294	continue;
8383e460 TM	295	spin_lock(&clp->cl_lock);
8383e460 TM	296	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
58d9714a	297	spin_unlock(&clp->cl_lock);
8383e460 TM	298	rcu_read_unlock();
	299	if (delegation)
	300	__nfs_inode_return_delegation(inode, delegation);
58d9714a	301	iput(inode);
26c78e15	302	goto restart;
58d9714a	303	}
8383e460	304	rcu_read_unlock();
58d9714a	305	out:
24c8dbbb	306	nfs_put_client(clp);
58d9714a TM	307	module_put_and_exit(0);
	308	}
	309
adfa6f98	310	void nfs_expire_all_delegations(struct nfs_client *clp)
58d9714a TM	311	{
	312	struct task_struct *task;
	313
	314	__module_get(THIS_MODULE);
	315	atomic_inc(&clp->cl_count);
	316	task = kthread_run(nfs_do_expire_all_delegations, clp,
	317	"%u.%u.%u.%u-delegreturn",
24c8dbbb	318	NIPQUAD(clp->cl_addr.sin_addr));
58d9714a TM	319	if (!IS_ERR(task))
58d9714a TM	320	return;
24c8dbbb	321	nfs_put_client(clp);
58d9714a TM	322	module_put(THIS_MODULE);
	323	}
	324
1da177e4 LT	325	/*
	326	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	327	*/
adfa6f98	328	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4 LT	329	{
	330	struct nfs_delegation *delegation;
	331	struct inode *inode;
	332
	333	if (clp == NULL)
	334	return;
	335	restart:
8383e460 TM	336	rcu_read_lock();
8383e460 TM	337	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	338	inode = igrab(delegation->inode);
	339	if (inode == NULL)
	340	continue;
8383e460 TM	341	spin_lock(&clp->cl_lock);
8383e460 TM	342	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	343	spin_unlock(&clp->cl_lock);
8383e460 TM	344	rcu_read_unlock();
	345	if (delegation != NULL)
	346	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	347	iput(inode);
	348	goto restart;
	349	}
8383e460	350	rcu_read_unlock();
1da177e4 LT	351	}
	352
	353	struct recall_threadargs {
	354	struct inode *inode;
adfa6f98	355	struct nfs_client *clp;
1da177e4 LT	356	const nfs4_stateid *stateid;
	357
	358	struct completion started;
	359	int result;
	360	};
	361
	362	static int recall_thread(void *data)
	363	{
	364	struct recall_threadargs args = (struct recall_threadargs )data;
	365	struct inode *inode = igrab(args->inode);
7539bbab	366	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	367	struct nfs_inode *nfsi = NFS_I(inode);
	368	struct nfs_delegation *delegation;
	369
	370	daemonize("nfsv4-delegreturn");
	371
	372	nfs_msync_inode(inode);
	373	down_read(&clp->cl_sem);
	374	down_write(&nfsi->rwsem);
	375	spin_lock(&clp->cl_lock);
90163027 TM	376	delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
90163027 TM	377	if (delegation != NULL)
1da177e4	378	args->result = 0;
90163027	379	else
1da177e4	380	args->result = -ENOENT;
1da177e4 LT	381	spin_unlock(&clp->cl_lock);
1da177e4 LT	382	complete(&args->started);
90163027	383	nfs_delegation_claim_opens(inode, args->stateid);
1da177e4 LT	384	up_write(&nfsi->rwsem);
	385	up_read(&clp->cl_sem);
	386	nfs_msync_inode(inode);
	387
	388	if (delegation != NULL)
	389	nfs_do_return_delegation(inode, delegation);
	390	iput(inode);
	391	module_put_and_exit(0);
	392	}
	393
	394	/*
	395	* Asynchronous delegation recall!
	396	*/
	397	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
	398	{
	399	struct recall_threadargs data = {
	400	.inode = inode,
	401	.stateid = stateid,
	402	};
	403	int status;
	404
	405	init_completion(&data.started);
	406	__module_get(THIS_MODULE);
	407	status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
	408	if (status < 0)
	409	goto out_module_put;
	410	wait_for_completion(&data.started);
	411	return data.result;
	412	out_module_put:
	413	module_put(THIS_MODULE);
	414	return status;
	415	}
	416
	417	/*
	418	* Retrieve the inode associated with a delegation
	419	*/
adfa6f98	420	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	421	{
	422	struct nfs_delegation *delegation;
	423	struct inode *res = NULL;
8383e460 TM	424	rcu_read_lock();
8383e460 TM	425	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	426	if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
	427	res = igrab(delegation->inode);
	428	break;
	429	}
	430	}
8383e460	431	rcu_read_unlock();
1da177e4 LT	432	return res;
	433	}
	434
	435	/*
	436	* Mark all delegations as needing to be reclaimed
	437	*/
adfa6f98	438	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	439	{
1da177e4 LT	440	struct nfs_delegation *delegation;
8383e460 TM	441	rcu_read_lock();
8383e460 TM	442	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
1da177e4	443	delegation->flags \|= NFS_DELEGATION_NEED_RECLAIM;
8383e460	444	rcu_read_unlock();
1da177e4 LT	445	}
	446
	447	/*
	448	* Reap all unclaimed delegations after reboot recovery is done
	449	*/
adfa6f98	450	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	451	{
8383e460 TM	452	struct nfs_delegation *delegation;
	453	restart:
	454	rcu_read_lock();
	455	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	456	if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
1da177e4 LT	457	continue;
8383e460 TM	458	spin_lock(&clp->cl_lock);
	459	delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
	460	spin_unlock(&clp->cl_lock);
	461	rcu_read_unlock();
	462	if (delegation != NULL)
905f8d16	463	nfs_free_delegation(delegation);
8383e460	464	goto restart;
1da177e4	465	}
8383e460	466	rcu_read_unlock();
1da177e4	467	}
3e4f6290 TM	468
	469	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	470	{
3e4f6290 TM	471	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	472	struct nfs_delegation *delegation;
8383e460	473	int ret = 0;
3e4f6290	474
8383e460 TM	475	rcu_read_lock();
8383e460 TM	476	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	477	if (delegation != NULL) {
3e4f6290 TM	478	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	479	ret = 1;
3e4f6290	480	}
8383e460 TM	481	rcu_read_unlock();
8383e460 TM	482	return ret;
3e4f6290	483	}