[deliverable/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 != NULL; 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",
						__func__, 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);
	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
	NFS_I(inode)->delegation_state = delegation->type;
	smp_wmb();
	put_rpccred(oldcred);
}

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

	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	nfs_free_delegation(delegation);
	return res;
}

static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
{
	struct inode *inode = NULL;

	spin_lock(&delegation->lock);
	if (delegation->inode != NULL)
		inode = igrab(delegation->inode);
	spin_unlock(&delegation->lock);
	return inode;
}

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

/*
 * 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;
	struct nfs_delegation *freeme = NULL;
	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_init(&delegation->lock);

	spin_lock(&clp->cl_lock);
	if (rcu_dereference(nfsi->delegation) != NULL) {
		if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
					sizeof(delegation->stateid)) == 0 &&
				delegation->type == nfsi->delegation->type) {
			goto out;
		}
		/*
		 * Deal with broken servers that hand out two
		 * delegations for the same file.
		 */
		dfprintk(FILE, "%s: server %s handed out "
				"a duplicate delegation!\n",
				__func__, clp->cl_hostname);
		if (delegation->type <= nfsi->delegation->type) {
			freeme = delegation;
			delegation = NULL;
			goto out;
		}
		freeme = nfs_detach_delegation_locked(nfsi, NULL);
	}
	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	nfsi->delegation_state = delegation->type;
	rcu_assign_pointer(nfsi->delegation, delegation);
	delegation = NULL;

	/* 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);

out:
	spin_unlock(&clp->cl_lock);
	if (delegation != NULL)
		nfs_free_delegation(delegation);
	if (freeme != NULL)
		nfs_do_return_delegation(inode, freeme, 0);
	return status;
}

/* 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_inode *nfsi = NFS_I(inode);

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

	return nfs_do_return_delegation(inode, delegation, 1);
}

/*
 * Return all delegations that have been marked for return
 */
void nfs_client_return_marked_delegations(struct nfs_client *clp)
{
	struct nfs_delegation *delegation;
	struct inode *inode;

restart:
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
			continue;
		inode = nfs_delegation_grab_inode(delegation);
		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();
}

/*
 * This function returns the delegation without reclaiming opens
 * or protecting against delegation reclaims.
 * It is therefore really only safe to be called from
 * nfs4_clear_inode()
 */
void nfs_inode_return_delegation_noreclaim(struct inode *inode)
{
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_delegation *delegation;

	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)
			nfs_do_return_delegation(inode, delegation, 0);
	}
}

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_super_return_all_delegations(struct super_block *sb)
{
	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
	struct nfs_delegation *delegation;

	if (clp == NULL)
		return;
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		spin_lock(&delegation->lock);
		if (delegation->inode != NULL && delegation->inode->i_sb == sb)
			set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
		spin_unlock(&delegation->lock);
	}
	rcu_read_unlock();
	nfs_client_return_marked_delegations(clp);
}

static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
{
	struct nfs_delegation *delegation;

	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
		set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	}
	rcu_read_unlock();
}

static void nfs_delegation_run_state_manager(struct nfs_client *clp)
{
	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
		nfs4_schedule_state_manager(clp);
}

void nfs_expire_all_delegations(struct nfs_client *clp)
{
	nfs_client_mark_return_all_delegations(clp);
	nfs_delegation_run_state_manager(clp);
}

/*
 * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 */
void nfs_handle_cb_pathdown(struct nfs_client *clp)
{
	if (clp == NULL)
		return;
	nfs_client_mark_return_all_delegations(clp);
}

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_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);
	nfs_msync_inode(inode);

	if (delegation != NULL)
		nfs_do_return_delegation(inode, delegation, 1);
	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) {
		spin_lock(&delegation->lock);
		if (delegation->inode != NULL &&
		    nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
			res = igrab(delegation->inode);
		}
		spin_unlock(&delegation->lock);
		if (res != NULL)
			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)
		set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
	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;
	struct inode *inode;
restart:
	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
			continue;
		inode = nfs_delegation_grab_inode(delegation);
		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_free_delegation(delegation);
		iput(inode);
		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
90dc7d27	52	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
888e694c TM	53	if (!(fl->fl_flags & (FL_POSIX\|FL_FLOCK)))
888e694c TM	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",
3110ff80	63	__func__, status);
888e694c TM	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	121	delegation->cred = get_rpccred(cred);
15c831bf	122	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1da177e4 LT	123	NFS_I(inode)->delegation_state = delegation->type;
1da177e4 LT	124	smp_wmb();
05c88bab	125	put_rpccred(oldcred);
1da177e4 LT	126	}
1da177e4 LT	127
57bfa891 TM	128	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
	129	{
	130	int res = 0;
	131
	132	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	133	nfs_free_delegation(delegation);
	134	return res;
	135	}
	136
86e89489 TM	137	static struct inode nfs_delegation_grab_inode(struct nfs_delegation delegation)
	138	{
	139	struct inode *inode = NULL;
	140
	141	spin_lock(&delegation->lock);
	142	if (delegation->inode != NULL)
	143	inode = igrab(delegation->inode);
	144	spin_unlock(&delegation->lock);
	145	return inode;
	146	}
	147
57bfa891 TM	148	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	149	{
	150	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
	151
	152	if (delegation == NULL)
	153	goto nomatch;
34310430	154	spin_lock(&delegation->lock);
57bfa891 TM	155	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
57bfa891 TM	156	sizeof(delegation->stateid.data)) != 0)
34310430	157	goto nomatch_unlock;
57bfa891	158	list_del_rcu(&delegation->super_list);
86e89489	159	delegation->inode = NULL;
57bfa891 TM	160	nfsi->delegation_state = 0;
57bfa891 TM	161	rcu_assign_pointer(nfsi->delegation, NULL);
34310430	162	spin_unlock(&delegation->lock);
57bfa891	163	return delegation;
34310430 TM	164	nomatch_unlock:
34310430 TM	165	spin_unlock(&delegation->lock);
57bfa891 TM	166	nomatch:
	167	return NULL;
	168	}
	169
1da177e4 LT	170	/*
	171	* Set up a delegation on an inode
	172	*/
	173	int nfs_inode_set_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	174	{
7539bbab	175	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	176	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	177	struct nfs_delegation *delegation;
57bfa891	178	struct nfs_delegation *freeme = NULL;
1da177e4 LT	179	int status = 0;
1da177e4 LT	180
f52720ca	181	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
1da177e4 LT	182	if (delegation == NULL)
	183	return -ENOMEM;
	184	memcpy(delegation->stateid.data, res->delegation.data,
	185	sizeof(delegation->stateid.data));
	186	delegation->type = res->delegation_type;
	187	delegation->maxsize = res->maxsize;
beb2a5ec	188	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	189	delegation->cred = get_rpccred(cred);
1da177e4 LT	190	delegation->inode = inode;
34310430	191	spin_lock_init(&delegation->lock);
1da177e4 LT	192
1da177e4 LT	193	spin_lock(&clp->cl_lock);
57bfa891	194	if (rcu_dereference(nfsi->delegation) != NULL) {
1da177e4	195	if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
57bfa891 TM	196	sizeof(delegation->stateid)) == 0 &&
	197	delegation->type == nfsi->delegation->type) {
	198	goto out;
1da177e4	199	}
57bfa891 TM	200	/*
	201	* Deal with broken servers that hand out two
	202	* delegations for the same file.
	203	*/
	204	dfprintk(FILE, "%s: server %s handed out "
	205	"a duplicate delegation!\n",
3110ff80	206	__func__, clp->cl_hostname);
57bfa891 TM	207	if (delegation->type <= nfsi->delegation->type) {
	208	freeme = delegation;
	209	delegation = NULL;
	210	goto out;
	211	}
	212	freeme = nfs_detach_delegation_locked(nfsi, NULL);
1da177e4	213	}
57bfa891 TM	214	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	215	nfsi->delegation_state = delegation->type;
	216	rcu_assign_pointer(nfsi->delegation, delegation);
	217	delegation = NULL;
412c77ce TM	218
	219	/* Ensure we revalidate the attributes and page cache! */
	220	spin_lock(&inode->i_lock);
	221	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	222	spin_unlock(&inode->i_lock);
	223
57bfa891	224	out:
1da177e4	225	spin_unlock(&clp->cl_lock);
603c83da TM	226	if (delegation != NULL)
603c83da TM	227	nfs_free_delegation(delegation);
57bfa891 TM	228	if (freeme != NULL)
57bfa891 TM	229	nfs_do_return_delegation(inode, freeme, 0);
1da177e4 LT	230	return status;
	231	}
	232
1da177e4 LT	233	/* Sync all data to disk upon delegation return */
	234	static void nfs_msync_inode(struct inode *inode)
	235	{
	236	filemap_fdatawrite(inode->i_mapping);
	237	nfs_wb_all(inode);
	238	filemap_fdatawait(inode->i_mapping);
	239	}
	240
	241	/*
	242	* Basic procedure for returning a delegation to the server
	243	*/
90163027	244	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation)
1da177e4	245	{
1da177e4	246	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	247
1da177e4 LT	248	nfs_msync_inode(inode);
1da177e4 LT	249	/* Guard against new delegated open calls */
1da177e4 LT	250	down_write(&nfsi->rwsem);
90163027	251	nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4	252	up_write(&nfsi->rwsem);
1da177e4 LT	253	nfs_msync_inode(inode);
1da177e4 LT	254
e6f81075	255	return nfs_do_return_delegation(inode, delegation, 1);
90163027 TM	256	}
90163027 TM	257
515d8611 TM	258	/*
	259	* Return all delegations that have been marked for return
	260	*/
707fb4b3	261	void nfs_client_return_marked_delegations(struct nfs_client *clp)
515d8611 TM	262	{
	263	struct nfs_delegation *delegation;
	264	struct inode *inode;
	265
	266	restart:
	267	rcu_read_lock();
	268	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	269	if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
	270	continue;
	271	inode = nfs_delegation_grab_inode(delegation);
	272	if (inode == NULL)
	273	continue;
	274	spin_lock(&clp->cl_lock);
	275	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
	276	spin_unlock(&clp->cl_lock);
	277	rcu_read_unlock();
	278	if (delegation != NULL)
	279	__nfs_inode_return_delegation(inode, delegation);
	280	iput(inode);
	281	goto restart;
	282	}
	283	rcu_read_unlock();
	284	}
	285
e6f81075 TM	286	/*
	287	* This function returns the delegation without reclaiming opens
	288	* or protecting against delegation reclaims.
	289	* It is therefore really only safe to be called from
	290	* nfs4_clear_inode()
	291	*/
	292	void nfs_inode_return_delegation_noreclaim(struct inode *inode)
	293	{
	294	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	295	struct nfs_inode *nfsi = NFS_I(inode);
	296	struct nfs_delegation *delegation;
	297
	298	if (rcu_dereference(nfsi->delegation) != NULL) {
	299	spin_lock(&clp->cl_lock);
	300	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	301	spin_unlock(&clp->cl_lock);
	302	if (delegation != NULL)
	303	nfs_do_return_delegation(inode, delegation, 0);
	304	}
	305	}
	306
90163027 TM	307	int nfs_inode_return_delegation(struct inode *inode)
	308	{
	309	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	310	struct nfs_inode *nfsi = NFS_I(inode);
	311	struct nfs_delegation *delegation;
	312	int err = 0;
	313
8383e460	314	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	315	spin_lock(&clp->cl_lock);
	316	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	317	spin_unlock(&clp->cl_lock);
	318	if (delegation != NULL)
	319	err = __nfs_inode_return_delegation(inode, delegation);
	320	}
	321	return err;
1da177e4 LT	322	}
	323
	324	/*
	325	* Return all delegations associated to a super block
	326	*/
515d8611	327	void nfs_super_return_all_delegations(struct super_block *sb)
1da177e4	328	{
7539bbab	329	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4	330	struct nfs_delegation *delegation;
1da177e4 LT	331
	332	if (clp == NULL)
	333	return;
8383e460 TM	334	rcu_read_lock();
8383e460 TM	335	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	336	spin_lock(&delegation->lock);
86e89489 TM	337	if (delegation->inode != NULL && delegation->inode->i_sb == sb)
515d8611	338	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
86e89489	339	spin_unlock(&delegation->lock);
1da177e4	340	}
8383e460	341	rcu_read_unlock();
515d8611 TM	342	nfs_client_return_marked_delegations(clp);
	343	}
	344
707fb4b3	345	static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
515d8611 TM	346	{
	347	struct nfs_delegation *delegation;
	348
	349	rcu_read_lock();
707fb4b3	350	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
515d8611	351	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
707fb4b3 TM	352	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
707fb4b3 TM	353	}
515d8611	354	rcu_read_unlock();
1da177e4 LT	355	}
1da177e4 LT	356
b0d3ded1	357	static void nfs_delegation_run_state_manager(struct nfs_client *clp)
58d9714a	358	{
b0d3ded1 TM	359	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
b0d3ded1 TM	360	nfs4_schedule_state_manager(clp);
58d9714a TM	361	}
58d9714a TM	362
adfa6f98	363	void nfs_expire_all_delegations(struct nfs_client *clp)
58d9714a	364	{
b0d3ded1 TM	365	nfs_client_mark_return_all_delegations(clp);
b0d3ded1 TM	366	nfs_delegation_run_state_manager(clp);
58d9714a TM	367	}
58d9714a TM	368
1da177e4 LT	369	/*
	370	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	371	*/
adfa6f98	372	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4	373	{
1da177e4 LT	374	if (clp == NULL)
1da177e4 LT	375	return;
707fb4b3	376	nfs_client_mark_return_all_delegations(clp);
1da177e4 LT	377	}
	378
	379	struct recall_threadargs {
	380	struct inode *inode;
adfa6f98	381	struct nfs_client *clp;
1da177e4 LT	382	const nfs4_stateid *stateid;
	383
	384	struct completion started;
	385	int result;
	386	};
	387
	388	static int recall_thread(void *data)
	389	{
	390	struct recall_threadargs args = (struct recall_threadargs )data;
	391	struct inode *inode = igrab(args->inode);
7539bbab	392	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	393	struct nfs_inode *nfsi = NFS_I(inode);
	394	struct nfs_delegation *delegation;
	395
	396	daemonize("nfsv4-delegreturn");
	397
	398	nfs_msync_inode(inode);
1da177e4 LT	399	down_write(&nfsi->rwsem);
1da177e4 LT	400	spin_lock(&clp->cl_lock);
90163027 TM	401	delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
90163027 TM	402	if (delegation != NULL)
1da177e4	403	args->result = 0;
90163027	404	else
1da177e4	405	args->result = -ENOENT;
1da177e4 LT	406	spin_unlock(&clp->cl_lock);
1da177e4 LT	407	complete(&args->started);
90163027	408	nfs_delegation_claim_opens(inode, args->stateid);
1da177e4	409	up_write(&nfsi->rwsem);
1da177e4 LT	410	nfs_msync_inode(inode);
	411
	412	if (delegation != NULL)
e6f81075	413	nfs_do_return_delegation(inode, delegation, 1);
1da177e4 LT	414	iput(inode);
	415	module_put_and_exit(0);
	416	}
	417
	418	/*
	419	* Asynchronous delegation recall!
	420	*/
	421	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
	422	{
	423	struct recall_threadargs data = {
	424	.inode = inode,
	425	.stateid = stateid,
	426	};
	427	int status;
	428
	429	init_completion(&data.started);
	430	__module_get(THIS_MODULE);
	431	status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
	432	if (status < 0)
	433	goto out_module_put;
	434	wait_for_completion(&data.started);
	435	return data.result;
	436	out_module_put:
	437	module_put(THIS_MODULE);
	438	return status;
	439	}
	440
	441	/*
	442	* Retrieve the inode associated with a delegation
	443	*/
adfa6f98	444	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	445	{
	446	struct nfs_delegation *delegation;
	447	struct inode *res = NULL;
8383e460 TM	448	rcu_read_lock();
8383e460 TM	449	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	450	spin_lock(&delegation->lock);
	451	if (delegation->inode != NULL &&
	452	nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1da177e4	453	res = igrab(delegation->inode);
1da177e4	454	}
86e89489 TM	455	spin_unlock(&delegation->lock);
	456	if (res != NULL)
	457	break;
1da177e4	458	}
8383e460	459	rcu_read_unlock();
1da177e4 LT	460	return res;
	461	}
	462
	463	/*
	464	* Mark all delegations as needing to be reclaimed
	465	*/
adfa6f98	466	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	467	{
1da177e4 LT	468	struct nfs_delegation *delegation;
8383e460 TM	469	rcu_read_lock();
8383e460 TM	470	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
15c831bf	471	set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
8383e460	472	rcu_read_unlock();
1da177e4 LT	473	}
	474
	475	/*
	476	* Reap all unclaimed delegations after reboot recovery is done
	477	*/
adfa6f98	478	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	479	{
8383e460	480	struct nfs_delegation *delegation;
86e89489	481	struct inode *inode;
8383e460 TM	482	restart:
	483	rcu_read_lock();
	484	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
15c831bf	485	if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
1da177e4	486	continue;
86e89489 TM	487	inode = nfs_delegation_grab_inode(delegation);
	488	if (inode == NULL)
	489	continue;
8383e460	490	spin_lock(&clp->cl_lock);
86e89489	491	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
8383e460 TM	492	spin_unlock(&clp->cl_lock);
	493	rcu_read_unlock();
	494	if (delegation != NULL)
905f8d16	495	nfs_free_delegation(delegation);
86e89489	496	iput(inode);
8383e460	497	goto restart;
1da177e4	498	}
8383e460	499	rcu_read_unlock();
1da177e4	500	}
3e4f6290 TM	501
	502	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	503	{
3e4f6290 TM	504	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	505	struct nfs_delegation *delegation;
8383e460	506	int ret = 0;
3e4f6290	507
8383e460 TM	508	rcu_read_lock();
8383e460 TM	509	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	510	if (delegation != NULL) {
3e4f6290 TM	511	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	512	ret = 1;
3e4f6290	513	}
8383e460 TM	514	rcu_read_unlock();
8383e460 TM	515	return ret;
3e4f6290	516	}