[mirror_ubuntu-artful-kernel.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);
}

/*
 * 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_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) {
		inode = NULL;
		spin_lock(&delegation->lock);
		if (delegation->inode != NULL && delegation->inode->i_sb == sb)
			inode = igrab(delegation->inode);
		spin_unlock(&delegation->lock);
		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 = 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)
			__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,
				"%s-delegreturn",
				rpc_peeraddr2str(clp->cl_rpcclient,
							RPC_DISPLAY_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 = 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();
}

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
e6f81075 TM	258	/*
	259	* This function returns the delegation without reclaiming opens
	260	* or protecting against delegation reclaims.
	261	* It is therefore really only safe to be called from
	262	* nfs4_clear_inode()
	263	*/
	264	void nfs_inode_return_delegation_noreclaim(struct inode *inode)
	265	{
	266	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	267	struct nfs_inode *nfsi = NFS_I(inode);
	268	struct nfs_delegation *delegation;
	269
	270	if (rcu_dereference(nfsi->delegation) != NULL) {
	271	spin_lock(&clp->cl_lock);
	272	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	273	spin_unlock(&clp->cl_lock);
	274	if (delegation != NULL)
	275	nfs_do_return_delegation(inode, delegation, 0);
	276	}
	277	}
	278
90163027 TM	279	int nfs_inode_return_delegation(struct inode *inode)
	280	{
	281	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	282	struct nfs_inode *nfsi = NFS_I(inode);
	283	struct nfs_delegation *delegation;
	284	int err = 0;
	285
8383e460	286	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	287	spin_lock(&clp->cl_lock);
	288	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	289	spin_unlock(&clp->cl_lock);
	290	if (delegation != NULL)
	291	err = __nfs_inode_return_delegation(inode, delegation);
	292	}
	293	return err;
1da177e4 LT	294	}
	295
	296	/*
	297	* Return all delegations associated to a super block
	298	*/
	299	void nfs_return_all_delegations(struct super_block *sb)
	300	{
7539bbab	301	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4 LT	302	struct nfs_delegation *delegation;
	303	struct inode *inode;
	304
	305	if (clp == NULL)
	306	return;
	307	restart:
8383e460 TM	308	rcu_read_lock();
8383e460 TM	309	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	310	inode = NULL;
	311	spin_lock(&delegation->lock);
	312	if (delegation->inode != NULL && delegation->inode->i_sb == sb)
	313	inode = igrab(delegation->inode);
	314	spin_unlock(&delegation->lock);
1da177e4 LT	315	if (inode == NULL)
1da177e4 LT	316	continue;
8383e460 TM	317	spin_lock(&clp->cl_lock);
8383e460 TM	318	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	319	spin_unlock(&clp->cl_lock);
8383e460 TM	320	rcu_read_unlock();
	321	if (delegation != NULL)
	322	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	323	iput(inode);
	324	goto restart;
	325	}
8383e460	326	rcu_read_unlock();
1da177e4 LT	327	}
1da177e4 LT	328
10afec90	329	static int nfs_do_expire_all_delegations(void *ptr)
58d9714a	330	{
adfa6f98	331	struct nfs_client *clp = ptr;
58d9714a TM	332	struct nfs_delegation *delegation;
58d9714a TM	333	struct inode *inode;
58d9714a TM	334
	335	allow_signal(SIGKILL);
	336	restart:
58d9714a TM	337	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
	338	goto out;
	339	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
	340	goto out;
8383e460 TM	341	rcu_read_lock();
8383e460 TM	342	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489	343	inode = nfs_delegation_grab_inode(delegation);
58d9714a TM	344	if (inode == NULL)
58d9714a TM	345	continue;
8383e460 TM	346	spin_lock(&clp->cl_lock);
8383e460 TM	347	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
58d9714a	348	spin_unlock(&clp->cl_lock);
8383e460 TM	349	rcu_read_unlock();
	350	if (delegation)
	351	__nfs_inode_return_delegation(inode, delegation);
58d9714a	352	iput(inode);
26c78e15	353	goto restart;
58d9714a	354	}
8383e460	355	rcu_read_unlock();
58d9714a	356	out:
24c8dbbb	357	nfs_put_client(clp);
58d9714a TM	358	module_put_and_exit(0);
	359	}
	360
adfa6f98	361	void nfs_expire_all_delegations(struct nfs_client *clp)
58d9714a TM	362	{
	363	struct task_struct *task;
	364
	365	__module_get(THIS_MODULE);
	366	atomic_inc(&clp->cl_count);
	367	task = kthread_run(nfs_do_expire_all_delegations, clp,
5d8515ca CL	368	"%s-delegreturn",
	369	rpc_peeraddr2str(clp->cl_rpcclient,
	370	RPC_DISPLAY_ADDR));
58d9714a TM	371	if (!IS_ERR(task))
58d9714a TM	372	return;
24c8dbbb	373	nfs_put_client(clp);
58d9714a TM	374	module_put(THIS_MODULE);
	375	}
	376
1da177e4 LT	377	/*
	378	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	379	*/
adfa6f98	380	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4 LT	381	{
	382	struct nfs_delegation *delegation;
	383	struct inode *inode;
	384
	385	if (clp == NULL)
	386	return;
	387	restart:
8383e460 TM	388	rcu_read_lock();
8383e460 TM	389	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489	390	inode = nfs_delegation_grab_inode(delegation);
1da177e4 LT	391	if (inode == NULL)
1da177e4 LT	392	continue;
8383e460 TM	393	spin_lock(&clp->cl_lock);
8383e460 TM	394	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
1da177e4	395	spin_unlock(&clp->cl_lock);
8383e460 TM	396	rcu_read_unlock();
	397	if (delegation != NULL)
	398	__nfs_inode_return_delegation(inode, delegation);
1da177e4 LT	399	iput(inode);
	400	goto restart;
	401	}
8383e460	402	rcu_read_unlock();
1da177e4 LT	403	}
	404
	405	struct recall_threadargs {
	406	struct inode *inode;
adfa6f98	407	struct nfs_client *clp;
1da177e4 LT	408	const nfs4_stateid *stateid;
	409
	410	struct completion started;
	411	int result;
	412	};
	413
	414	static int recall_thread(void *data)
	415	{
	416	struct recall_threadargs args = (struct recall_threadargs )data;
	417	struct inode *inode = igrab(args->inode);
7539bbab	418	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	419	struct nfs_inode *nfsi = NFS_I(inode);
	420	struct nfs_delegation *delegation;
	421
	422	daemonize("nfsv4-delegreturn");
	423
	424	nfs_msync_inode(inode);
1da177e4 LT	425	down_write(&nfsi->rwsem);
1da177e4 LT	426	spin_lock(&clp->cl_lock);
90163027 TM	427	delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
90163027 TM	428	if (delegation != NULL)
1da177e4	429	args->result = 0;
90163027	430	else
1da177e4	431	args->result = -ENOENT;
1da177e4 LT	432	spin_unlock(&clp->cl_lock);
1da177e4 LT	433	complete(&args->started);
90163027	434	nfs_delegation_claim_opens(inode, args->stateid);
1da177e4	435	up_write(&nfsi->rwsem);
1da177e4 LT	436	nfs_msync_inode(inode);
	437
	438	if (delegation != NULL)
e6f81075	439	nfs_do_return_delegation(inode, delegation, 1);
1da177e4 LT	440	iput(inode);
	441	module_put_and_exit(0);
	442	}
	443
	444	/*
	445	* Asynchronous delegation recall!
	446	*/
	447	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
	448	{
	449	struct recall_threadargs data = {
	450	.inode = inode,
	451	.stateid = stateid,
	452	};
	453	int status;
	454
	455	init_completion(&data.started);
	456	__module_get(THIS_MODULE);
	457	status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
	458	if (status < 0)
	459	goto out_module_put;
	460	wait_for_completion(&data.started);
	461	return data.result;
	462	out_module_put:
	463	module_put(THIS_MODULE);
	464	return status;
	465	}
	466
	467	/*
	468	* Retrieve the inode associated with a delegation
	469	*/
adfa6f98	470	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	471	{
	472	struct nfs_delegation *delegation;
	473	struct inode *res = NULL;
8383e460 TM	474	rcu_read_lock();
8383e460 TM	475	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	476	spin_lock(&delegation->lock);
	477	if (delegation->inode != NULL &&
	478	nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1da177e4	479	res = igrab(delegation->inode);
1da177e4	480	}
86e89489 TM	481	spin_unlock(&delegation->lock);
	482	if (res != NULL)
	483	break;
1da177e4	484	}
8383e460	485	rcu_read_unlock();
1da177e4 LT	486	return res;
	487	}
	488
	489	/*
	490	* Mark all delegations as needing to be reclaimed
	491	*/
adfa6f98	492	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	493	{
1da177e4 LT	494	struct nfs_delegation *delegation;
8383e460 TM	495	rcu_read_lock();
8383e460 TM	496	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
15c831bf	497	set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
8383e460	498	rcu_read_unlock();
1da177e4 LT	499	}
	500
	501	/*
	502	* Reap all unclaimed delegations after reboot recovery is done
	503	*/
adfa6f98	504	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	505	{
8383e460	506	struct nfs_delegation *delegation;
86e89489	507	struct inode *inode;
8383e460 TM	508	restart:
	509	rcu_read_lock();
	510	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
15c831bf	511	if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
1da177e4	512	continue;
86e89489 TM	513	inode = nfs_delegation_grab_inode(delegation);
	514	if (inode == NULL)
	515	continue;
8383e460	516	spin_lock(&clp->cl_lock);
86e89489	517	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
8383e460 TM	518	spin_unlock(&clp->cl_lock);
	519	rcu_read_unlock();
	520	if (delegation != NULL)
905f8d16	521	nfs_free_delegation(delegation);
86e89489	522	iput(inode);
8383e460	523	goto restart;
1da177e4	524	}
8383e460	525	rcu_read_unlock();
1da177e4	526	}
3e4f6290 TM	527
	528	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	529	{
3e4f6290 TM	530	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	531	struct nfs_delegation *delegation;
8383e460	532	int ret = 0;
3e4f6290	533
8383e460 TM	534	rcu_read_lock();
8383e460 TM	535	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	536	if (delegation != NULL) {
3e4f6290 TM	537	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	538	ret = 1;
3e4f6290	539	}
8383e460 TM	540	rcu_read_unlock();
8383e460 TM	541	return ret;
3e4f6290	542	}