[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);
	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);
	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);
f99d49ad	171	kfree(delegation);
1da177e4 LT	172	return status;
	173	}
	174
	175	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation)
	176	{
	177	int res = 0;
	178
1da177e4	179	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
905f8d16	180	nfs_free_delegation(delegation);
1da177e4 LT	181	return res;
	182	}
	183
	184	/* Sync all data to disk upon delegation return */
	185	static void nfs_msync_inode(struct inode *inode)
	186	{
	187	filemap_fdatawrite(inode->i_mapping);
	188	nfs_wb_all(inode);
	189	filemap_fdatawait(inode->i_mapping);
	190	}
	191
	192	/*
	193	* Basic procedure for returning a delegation to the server
	194	*/
90163027	195	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation)
1da177e4	196	{
7539bbab	197	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4	198	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	199
	200	nfs_msync_inode(inode);
	201	down_read(&clp->cl_sem);
	202	/* Guard against new delegated open calls */
	203	down_write(&nfsi->rwsem);
90163027	204	nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4 LT	205	up_write(&nfsi->rwsem);
	206	up_read(&clp->cl_sem);
	207	nfs_msync_inode(inode);
	208
90163027 TM	209	return nfs_do_return_delegation(inode, delegation);
	210	}
	211
	212	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	213	{
8383e460	214	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
90163027 TM	215
	216	if (delegation == NULL)
	217	goto nomatch;
	218	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
	219	sizeof(delegation->stateid.data)) != 0)
	220	goto nomatch;
8383e460	221	list_del_rcu(&delegation->super_list);
90163027	222	nfsi->delegation_state = 0;
8383e460	223	rcu_assign_pointer(nfsi->delegation, NULL);
90163027 TM	224	return delegation;
	225	nomatch:
	226	return NULL;
	227	}
	228
	229	int nfs_inode_return_delegation(struct inode *inode)
	230	{
	231	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	232	struct nfs_inode *nfsi = NFS_I(inode);
	233	struct nfs_delegation *delegation;
	234	int err = 0;
	235
8383e460	236	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	237	spin_lock(&clp->cl_lock);
	238	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	239	spin_unlock(&clp->cl_lock);
	240	if (delegation != NULL)
	241	err = __nfs_inode_return_delegation(inode, delegation);
	242	}
	243	return err;
1da177e4 LT	244	}
	245
	246	/*
	247	* Return all delegations associated to a super block
	248	*/
	249	void nfs_return_all_delegations(struct super_block *sb)
	250	{
7539bbab	251	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4 LT	252	struct nfs_delegation *delegation;
	253	struct inode *inode;
	254
	255	if (clp == NULL)
	256	return;
	257	restart:
8383e460 TM	258	rcu_read_lock();
8383e460 TM	259	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	260	if (delegation->inode->i_sb != sb)
	261	continue;
	262	inode = igrab(delegation->inode);
	263	if (inode == NULL)
	264	continue;
8383e460 TM	265	spin_lock(&clp->cl_lock);
8383e460 TM	266	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	267	spin_unlock(&clp->cl_lock);
8383e460 TM	268	rcu_read_unlock();
	269	if (delegation != NULL)
	270	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	271	iput(inode);
	272	goto restart;
	273	}
8383e460	274	rcu_read_unlock();
1da177e4 LT	275	}
1da177e4 LT	276
10afec90	277	static int nfs_do_expire_all_delegations(void *ptr)
58d9714a	278	{
adfa6f98	279	struct nfs_client *clp = ptr;
58d9714a TM	280	struct nfs_delegation *delegation;
58d9714a TM	281	struct inode *inode;
58d9714a TM	282
	283	allow_signal(SIGKILL);
	284	restart:
58d9714a TM	285	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
	286	goto out;
	287	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
	288	goto out;
8383e460 TM	289	rcu_read_lock();
8383e460 TM	290	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
58d9714a TM	291	inode = igrab(delegation->inode);
	292	if (inode == NULL)
	293	continue;
8383e460 TM	294	spin_lock(&clp->cl_lock);
8383e460 TM	295	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
58d9714a	296	spin_unlock(&clp->cl_lock);
8383e460 TM	297	rcu_read_unlock();
	298	if (delegation)
	299	__nfs_inode_return_delegation(inode, delegation);
58d9714a	300	iput(inode);
26c78e15	301	goto restart;
58d9714a	302	}
8383e460	303	rcu_read_unlock();
58d9714a	304	out:
24c8dbbb	305	nfs_put_client(clp);
58d9714a TM	306	module_put_and_exit(0);
	307	}
	308
adfa6f98	309	void nfs_expire_all_delegations(struct nfs_client *clp)
58d9714a TM	310	{
	311	struct task_struct *task;
	312
	313	__module_get(THIS_MODULE);
	314	atomic_inc(&clp->cl_count);
	315	task = kthread_run(nfs_do_expire_all_delegations, clp,
	316	"%u.%u.%u.%u-delegreturn",
24c8dbbb	317	NIPQUAD(clp->cl_addr.sin_addr));
58d9714a TM	318	if (!IS_ERR(task))
58d9714a TM	319	return;
24c8dbbb	320	nfs_put_client(clp);
58d9714a TM	321	module_put(THIS_MODULE);
	322	}
	323
1da177e4 LT	324	/*
	325	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	326	*/
adfa6f98	327	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4 LT	328	{
	329	struct nfs_delegation *delegation;
	330	struct inode *inode;
	331
	332	if (clp == NULL)
	333	return;
	334	restart:
8383e460 TM	335	rcu_read_lock();
8383e460 TM	336	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	337	inode = igrab(delegation->inode);
	338	if (inode == NULL)
	339	continue;
8383e460 TM	340	spin_lock(&clp->cl_lock);
8383e460 TM	341	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	342	spin_unlock(&clp->cl_lock);
8383e460 TM	343	rcu_read_unlock();
	344	if (delegation != NULL)
	345	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	346	iput(inode);
	347	goto restart;
	348	}
8383e460	349	rcu_read_unlock();
1da177e4 LT	350	}
	351
	352	struct recall_threadargs {
	353	struct inode *inode;
adfa6f98	354	struct nfs_client *clp;
1da177e4 LT	355	const nfs4_stateid *stateid;
	356
	357	struct completion started;
	358	int result;
	359	};
	360
	361	static int recall_thread(void *data)
	362	{
	363	struct recall_threadargs args = (struct recall_threadargs )data;
	364	struct inode *inode = igrab(args->inode);
7539bbab	365	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	366	struct nfs_inode *nfsi = NFS_I(inode);
	367	struct nfs_delegation *delegation;
	368
	369	daemonize("nfsv4-delegreturn");
	370
	371	nfs_msync_inode(inode);
	372	down_read(&clp->cl_sem);
	373	down_write(&nfsi->rwsem);
	374	spin_lock(&clp->cl_lock);
90163027 TM	375	delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
90163027 TM	376	if (delegation != NULL)
1da177e4	377	args->result = 0;
90163027	378	else
1da177e4	379	args->result = -ENOENT;
1da177e4 LT	380	spin_unlock(&clp->cl_lock);
1da177e4 LT	381	complete(&args->started);
90163027	382	nfs_delegation_claim_opens(inode, args->stateid);
1da177e4 LT	383	up_write(&nfsi->rwsem);
	384	up_read(&clp->cl_sem);
	385	nfs_msync_inode(inode);
	386
	387	if (delegation != NULL)
	388	nfs_do_return_delegation(inode, delegation);
	389	iput(inode);
	390	module_put_and_exit(0);
	391	}
	392
	393	/*
	394	* Asynchronous delegation recall!
	395	*/
	396	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
	397	{
	398	struct recall_threadargs data = {
	399	.inode = inode,
	400	.stateid = stateid,
	401	};
	402	int status;
	403
	404	init_completion(&data.started);
	405	__module_get(THIS_MODULE);
	406	status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
	407	if (status < 0)
	408	goto out_module_put;
	409	wait_for_completion(&data.started);
	410	return data.result;
	411	out_module_put:
	412	module_put(THIS_MODULE);
	413	return status;
	414	}
	415
	416	/*
	417	* Retrieve the inode associated with a delegation
	418	*/
adfa6f98	419	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	420	{
	421	struct nfs_delegation *delegation;
	422	struct inode *res = NULL;
8383e460 TM	423	rcu_read_lock();
8383e460 TM	424	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	425	if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
	426	res = igrab(delegation->inode);
	427	break;
	428	}
	429	}
8383e460	430	rcu_read_unlock();
1da177e4 LT	431	return res;
	432	}
	433
	434	/*
	435	* Mark all delegations as needing to be reclaimed
	436	*/
adfa6f98	437	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	438	{
1da177e4 LT	439	struct nfs_delegation *delegation;
8383e460 TM	440	rcu_read_lock();
8383e460 TM	441	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
1da177e4	442	delegation->flags \|= NFS_DELEGATION_NEED_RECLAIM;
8383e460	443	rcu_read_unlock();
1da177e4 LT	444	}
	445
	446	/*
	447	* Reap all unclaimed delegations after reboot recovery is done
	448	*/
adfa6f98	449	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	450	{
8383e460 TM	451	struct nfs_delegation *delegation;
	452	restart:
	453	rcu_read_lock();
	454	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
1da177e4 LT	455	if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
1da177e4 LT	456	continue;
8383e460 TM	457	spin_lock(&clp->cl_lock);
	458	delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
	459	spin_unlock(&clp->cl_lock);
	460	rcu_read_unlock();
	461	if (delegation != NULL)
905f8d16	462	nfs_free_delegation(delegation);
8383e460	463	goto restart;
1da177e4	464	}
8383e460	465	rcu_read_unlock();
1da177e4	466	}
3e4f6290 TM	467
	468	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	469	{
3e4f6290 TM	470	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	471	struct nfs_delegation *delegation;
8383e460	472	int ret = 0;
3e4f6290	473
8383e460 TM	474	rcu_read_lock();
8383e460 TM	475	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	476	if (delegation != NULL) {
3e4f6290 TM	477	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	478	ret = 1;
3e4f6290	479	}
8383e460 TM	480	rcu_read_unlock();
8383e460 TM	481	return ret;
3e4f6290	482	}