[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_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;

	/* Ensure we first revalidate the attributes and page cache! */
	if ((nfsi->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_ATTR)))
		__nfs_revalidate_inode(NFS_SERVER(inode), inode);

	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;
		}
	}
	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
b3c52da3 TM	127	/* Ensure we first revalidate the attributes and page cache! */
	128	if ((nfsi->cache_validity & (NFS_INO_REVAL_PAGECACHE\|NFS_INO_INVALID_ATTR)))
	129	__nfs_revalidate_inode(NFS_SERVER(inode), inode);
	130
f52720ca	131	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
1da177e4 LT	132	if (delegation == NULL)
	133	return -ENOMEM;
	134	memcpy(delegation->stateid.data, res->delegation.data,
	135	sizeof(delegation->stateid.data));
	136	delegation->type = res->delegation_type;
	137	delegation->maxsize = res->maxsize;
beb2a5ec	138	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	139	delegation->cred = get_rpccred(cred);
	140	delegation->inode = inode;
	141
	142	spin_lock(&clp->cl_lock);
8383e460 TM	143	if (rcu_dereference(nfsi->delegation) == NULL) {
8383e460 TM	144	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
1da177e4	145	nfsi->delegation_state = delegation->type;
8383e460	146	rcu_assign_pointer(nfsi->delegation, delegation);
1da177e4 LT	147	delegation = NULL;
	148	} else {
	149	if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
	150	sizeof(delegation->stateid)) != 0 \|\|
	151	delegation->type != nfsi->delegation->type) {
	152	printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
24c8dbbb	153	__FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
1da177e4 LT	154	status = -EIO;
	155	}
	156	}
	157	spin_unlock(&clp->cl_lock);
f99d49ad	158	kfree(delegation);
1da177e4 LT	159	return status;
	160	}
	161
	162	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation)
	163	{
	164	int res = 0;
	165
1da177e4	166	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
8383e460	167	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
1da177e4 LT	168	return res;
	169	}
	170
	171	/* Sync all data to disk upon delegation return */
	172	static void nfs_msync_inode(struct inode *inode)
	173	{
	174	filemap_fdatawrite(inode->i_mapping);
	175	nfs_wb_all(inode);
	176	filemap_fdatawait(inode->i_mapping);
	177	}
	178
	179	/*
	180	* Basic procedure for returning a delegation to the server
	181	*/
90163027	182	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation)
1da177e4	183	{
7539bbab	184	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4	185	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	186
	187	nfs_msync_inode(inode);
	188	down_read(&clp->cl_sem);
	189	/* Guard against new delegated open calls */
	190	down_write(&nfsi->rwsem);
90163027	191	nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4 LT	192	up_write(&nfsi->rwsem);
	193	up_read(&clp->cl_sem);
	194	nfs_msync_inode(inode);
	195
90163027 TM	196	return nfs_do_return_delegation(inode, delegation);
	197	}
	198
	199	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	200	{
8383e460	201	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
90163027 TM	202
	203	if (delegation == NULL)
	204	goto nomatch;
	205	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
	206	sizeof(delegation->stateid.data)) != 0)
	207	goto nomatch;
8383e460	208	list_del_rcu(&delegation->super_list);
90163027	209	nfsi->delegation_state = 0;
8383e460	210	rcu_assign_pointer(nfsi->delegation, NULL);
90163027 TM	211	return delegation;
	212	nomatch:
	213	return NULL;
	214	}
	215
	216	int nfs_inode_return_delegation(struct inode *inode)
	217	{
	218	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	219	struct nfs_inode *nfsi = NFS_I(inode);
	220	struct nfs_delegation *delegation;
	221	int err = 0;
	222
8383e460	223	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	224	spin_lock(&clp->cl_lock);
	225	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	226	spin_unlock(&clp->cl_lock);
	227	if (delegation != NULL)
	228	err = __nfs_inode_return_delegation(inode, delegation);
	229	}
	230	return err;
1da177e4 LT	231	}
	232
	233	/*
	234	* Return all delegations associated to a super block
	235	*/
	236	void nfs_return_all_delegations(struct super_block *sb)
	237	{
7539bbab	238	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4 LT	239	struct nfs_delegation *delegation;
	240	struct inode *inode;
	241
	242	if (clp == NULL)
	243	return;
	244	restart:
8383e460 TM	245	rcu_read_lock();
8383e460 TM	246	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	247	if (delegation->inode->i_sb != sb)
	248	continue;
	249	inode = igrab(delegation->inode);
	250	if (inode == NULL)
	251	continue;
8383e460 TM	252	spin_lock(&clp->cl_lock);
8383e460 TM	253	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	254	spin_unlock(&clp->cl_lock);
8383e460 TM	255	rcu_read_unlock();
	256	if (delegation != NULL)
	257	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	258	iput(inode);
	259	goto restart;
	260	}
8383e460	261	rcu_read_unlock();
1da177e4 LT	262	}
1da177e4 LT	263
10afec90	264	static int nfs_do_expire_all_delegations(void *ptr)
58d9714a	265	{
adfa6f98	266	struct nfs_client *clp = ptr;
58d9714a TM	267	struct nfs_delegation *delegation;
58d9714a TM	268	struct inode *inode;
58d9714a TM	269
	270	allow_signal(SIGKILL);
	271	restart:
58d9714a TM	272	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
	273	goto out;
	274	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
	275	goto out;
8383e460 TM	276	rcu_read_lock();
8383e460 TM	277	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
58d9714a TM	278	inode = igrab(delegation->inode);
	279	if (inode == NULL)
	280	continue;
8383e460 TM	281	spin_lock(&clp->cl_lock);
8383e460 TM	282	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
58d9714a	283	spin_unlock(&clp->cl_lock);
8383e460 TM	284	rcu_read_unlock();
	285	if (delegation)
	286	__nfs_inode_return_delegation(inode, delegation);
58d9714a	287	iput(inode);
26c78e15	288	goto restart;
58d9714a	289	}
8383e460	290	rcu_read_unlock();
58d9714a	291	out:
24c8dbbb	292	nfs_put_client(clp);
58d9714a TM	293	module_put_and_exit(0);
	294	}
	295
adfa6f98	296	void nfs_expire_all_delegations(struct nfs_client *clp)
58d9714a TM	297	{
	298	struct task_struct *task;
	299
	300	__module_get(THIS_MODULE);
	301	atomic_inc(&clp->cl_count);
	302	task = kthread_run(nfs_do_expire_all_delegations, clp,
	303	"%u.%u.%u.%u-delegreturn",
24c8dbbb	304	NIPQUAD(clp->cl_addr.sin_addr));
58d9714a TM	305	if (!IS_ERR(task))
58d9714a TM	306	return;
24c8dbbb	307	nfs_put_client(clp);
58d9714a TM	308	module_put(THIS_MODULE);
	309	}
	310
1da177e4 LT	311	/*
	312	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	313	*/
adfa6f98	314	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4 LT	315	{
	316	struct nfs_delegation *delegation;
	317	struct inode *inode;
	318
	319	if (clp == NULL)
	320	return;
	321	restart:
8383e460 TM	322	rcu_read_lock();
8383e460 TM	323	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	324	inode = igrab(delegation->inode);
	325	if (inode == NULL)
	326	continue;
8383e460 TM	327	spin_lock(&clp->cl_lock);
8383e460 TM	328	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	329	spin_unlock(&clp->cl_lock);
8383e460 TM	330	rcu_read_unlock();
	331	if (delegation != NULL)
	332	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	333	iput(inode);
	334	goto restart;
	335	}
8383e460	336	rcu_read_unlock();
1da177e4 LT	337	}
	338
	339	struct recall_threadargs {
	340	struct inode *inode;
adfa6f98	341	struct nfs_client *clp;
1da177e4 LT	342	const nfs4_stateid *stateid;
	343
	344	struct completion started;
	345	int result;
	346	};
	347
	348	static int recall_thread(void *data)
	349	{
	350	struct recall_threadargs args = (struct recall_threadargs )data;
	351	struct inode *inode = igrab(args->inode);
7539bbab	352	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	353	struct nfs_inode *nfsi = NFS_I(inode);
	354	struct nfs_delegation *delegation;
	355
	356	daemonize("nfsv4-delegreturn");
	357
	358	nfs_msync_inode(inode);
	359	down_read(&clp->cl_sem);
	360	down_write(&nfsi->rwsem);
	361	spin_lock(&clp->cl_lock);
90163027 TM	362	delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
90163027 TM	363	if (delegation != NULL)
1da177e4	364	args->result = 0;
90163027	365	else
1da177e4	366	args->result = -ENOENT;
1da177e4 LT	367	spin_unlock(&clp->cl_lock);
1da177e4 LT	368	complete(&args->started);
90163027	369	nfs_delegation_claim_opens(inode, args->stateid);
1da177e4 LT	370	up_write(&nfsi->rwsem);
	371	up_read(&clp->cl_sem);
	372	nfs_msync_inode(inode);
	373
	374	if (delegation != NULL)
	375	nfs_do_return_delegation(inode, delegation);
	376	iput(inode);
	377	module_put_and_exit(0);
	378	}
	379
	380	/*
	381	* Asynchronous delegation recall!
	382	*/
	383	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
	384	{
	385	struct recall_threadargs data = {
	386	.inode = inode,
	387	.stateid = stateid,
	388	};
	389	int status;
	390
	391	init_completion(&data.started);
	392	__module_get(THIS_MODULE);
	393	status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
	394	if (status < 0)
	395	goto out_module_put;
	396	wait_for_completion(&data.started);
	397	return data.result;
	398	out_module_put:
	399	module_put(THIS_MODULE);
	400	return status;
	401	}
	402
	403	/*
	404	* Retrieve the inode associated with a delegation
	405	*/
adfa6f98	406	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	407	{
	408	struct nfs_delegation *delegation;
	409	struct inode *res = NULL;
8383e460 TM	410	rcu_read_lock();
8383e460 TM	411	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	412	if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
	413	res = igrab(delegation->inode);
	414	break;
	415	}
	416	}
8383e460	417	rcu_read_unlock();
1da177e4 LT	418	return res;
	419	}
	420
	421	/*
	422	* Mark all delegations as needing to be reclaimed
	423	*/
adfa6f98	424	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	425	{
1da177e4 LT	426	struct nfs_delegation *delegation;
8383e460 TM	427	rcu_read_lock();
8383e460 TM	428	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
1da177e4	429	delegation->flags \|= NFS_DELEGATION_NEED_RECLAIM;
8383e460	430	rcu_read_unlock();
1da177e4 LT	431	}
	432
	433	/*
	434	* Reap all unclaimed delegations after reboot recovery is done
	435	*/
adfa6f98	436	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	437	{
8383e460 TM	438	struct nfs_delegation *delegation;
	439	restart:
	440	rcu_read_lock();
	441	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	442	if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
1da177e4 LT	443	continue;
8383e460 TM	444	spin_lock(&clp->cl_lock);
	445	delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
	446	spin_unlock(&clp->cl_lock);
	447	rcu_read_unlock();
	448	if (delegation != NULL)
	449	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	450	goto restart;
1da177e4	451	}
8383e460	452	rcu_read_unlock();
1da177e4	453	}
3e4f6290 TM	454
	455	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	456	{
3e4f6290 TM	457	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	458	struct nfs_delegation *delegation;
8383e460	459	int ret = 0;
3e4f6290	460
8383e460 TM	461	rcu_read_lock();
8383e460 TM	462	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	463	if (delegation != NULL) {
3e4f6290 TM	464	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	465	ret = 1;
3e4f6290	466	}
8383e460 TM	467	rcu_read_unlock();
8383e460 TM	468	return ret;
3e4f6290	469	}