[net-next-2.6.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/slab.h>
#include <linux/smp_lock.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);
}

void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
{
	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
}

int nfs_have_delegation(struct inode *inode, fmode_t flags)
{
	struct nfs_delegation *delegation;
	int ret = 0;

	flags &= FMODE_READ|FMODE_WRITE;
	rcu_read_lock();
	delegation = rcu_dereference(NFS_I(inode)->delegation);
	if (delegation != NULL && (delegation->type & flags) == flags) {
		nfs_mark_delegation_referenced(delegation);
		ret = 1;
	}
	rcu_read_unlock();
	return ret;
}

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 = 0;

	if (inode->i_flock == NULL)
		goto out;

	/* Protect inode->i_flock using the BKL */
	lock_kernel();
	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;
		unlock_kernel();
		status = nfs4_lock_delegation_recall(state, fl);
		if (status < 0)
			goto out;
		lock_kernel();
	}
	unlock_kernel();
out:
	return status;
}

static int 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 err;
		goto again;
	}
	spin_unlock(&inode->i_lock);
	return 0;
}

/*
 * 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;
	delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
	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, int issync)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	int err;

	/*
	 * Guard against new delegated open/lock/unlock calls and against
	 * state recovery
	 */
	down_write(&nfsi->rwsem);
	err = nfs_delegation_claim_opens(inode, &delegation->stateid);
	up_write(&nfsi->rwsem);
	if (err)
		goto out;

	err = nfs_do_return_delegation(inode, delegation, issync);
out:
	return err;
}

/*
 * Return all delegations that have been marked for return
 */
int nfs_client_return_marked_delegations(struct nfs_client *clp)
{
	struct nfs_delegation *delegation;
	struct inode *inode;
	int err = 0;

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) {
			filemap_flush(inode->i_mapping);
			err = __nfs_inode_return_delegation(inode, delegation, 0);
		}
		iput(inode);
		if (!err)
			goto restart;
		set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
		return err;
	}
	rcu_read_unlock();
	return 0;
}

/*
 * 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) {
			nfs_msync_inode(inode);
			err = __nfs_inode_return_delegation(inode, delegation, 1);
		}
	}
	return err;
}

static void nfs_mark_return_delegation(struct nfs_client *clp, struct nfs_delegation *delegation)
{
	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
}

/*
 * 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();
	if (nfs_client_return_marked_delegations(clp) != 0)
		nfs4_schedule_state_manager(clp);
}

static
void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
{
	struct nfs_delegation *delegation;

	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
			continue;
		if (delegation->type & flags)
			nfs_mark_return_delegation(clp, delegation);
	}
	rcu_read_unlock();
}

static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
{
	nfs_client_mark_return_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
}

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_delegation_types(struct nfs_client *clp, fmode_t flags)
{
	nfs_client_mark_return_all_delegation_types(clp, flags);
	nfs_delegation_run_state_manager(clp);
}

void nfs_expire_all_delegations(struct nfs_client *clp)
{
	nfs_expire_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
}

/*
 * 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);
}

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

	rcu_read_lock();
	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
		if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
			continue;
		nfs_mark_return_delegation(clp, delegation);
	}
	rcu_read_unlock();
}

void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
{
	nfs_client_mark_return_unreferenced_delegations(clp);
	nfs_delegation_run_state_manager(clp);
}

/*
 * Asynchronous delegation recall!
 */
int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid,
				      int (*validate_stateid)(struct nfs_delegation *delegation,
							      const nfs4_stateid *stateid))
{
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	struct nfs_delegation *delegation;

	rcu_read_lock();
	delegation = rcu_dereference(NFS_I(inode)->delegation);

	if (!validate_stateid(delegation, stateid)) {
		rcu_read_unlock();
		return -ENOENT;
	}

	nfs_mark_return_delegation(clp, delegation);
	rcu_read_unlock();
	nfs_delegation_run_state_manager(clp);
	return 0;
}

/*
 * 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>
1da177e4 LT	12	#include <linux/sched.h>
5a0e3ad6	13	#include <linux/slab.h>
405f5571	14	#include <linux/smp_lock.h>
1da177e4 LT	15	#include <linux/spinlock.h>
	16
	17	#include <linux/nfs4.h>
	18	#include <linux/nfs_fs.h>
	19	#include <linux/nfs_xdr.h>
	20
4ce79717	21	#include "nfs4_fs.h"
1da177e4	22	#include "delegation.h"
24c8dbbb	23	#include "internal.h"
1da177e4	24
905f8d16	25	static void nfs_do_free_delegation(struct nfs_delegation *delegation)
1da177e4	26	{
1da177e4 LT	27	kfree(delegation);
	28	}
	29
8383e460 TM	30	static void nfs_free_delegation_callback(struct rcu_head *head)
	31	{
	32	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
	33
905f8d16 TM	34	nfs_do_free_delegation(delegation);
	35	}
	36
	37	static void nfs_free_delegation(struct nfs_delegation *delegation)
	38	{
	39	struct rpc_cred *cred;
	40
	41	cred = rcu_dereference(delegation->cred);
	42	rcu_assign_pointer(delegation->cred, NULL);
	43	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	44	if (cred)
	45	put_rpccred(cred);
8383e460 TM	46	}
8383e460 TM	47
b7391f44 TM	48	void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
	49	{
	50	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
	51	}
	52
bd7bf9d5	53	int nfs_have_delegation(struct inode *inode, fmode_t flags)
b7391f44 TM	54	{
	55	struct nfs_delegation *delegation;
	56	int ret = 0;
	57
	58	flags &= FMODE_READ\|FMODE_WRITE;
	59	rcu_read_lock();
	60	delegation = rcu_dereference(NFS_I(inode)->delegation);
	61	if (delegation != NULL && (delegation->type & flags) == flags) {
	62	nfs_mark_delegation_referenced(delegation);
	63	ret = 1;
	64	}
	65	rcu_read_unlock();
	66	return ret;
	67	}
	68
888e694c TM	69	static int nfs_delegation_claim_locks(struct nfs_open_context ctx, struct nfs4_state state)
	70	{
	71	struct inode *inode = state->inode;
	72	struct file_lock *fl;
d5122201	73	int status = 0;
888e694c	74
3f09df70 TM	75	if (inode->i_flock == NULL)
	76	goto out;
	77
	78	/* Protect inode->i_flock using the BKL */
	79	lock_kernel();
90dc7d27	80	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
888e694c TM	81	if (!(fl->fl_flags & (FL_POSIX\|FL_FLOCK)))
888e694c TM	82	continue;
cd3758e3	83	if (nfs_file_open_context(fl->fl_file) != ctx)
888e694c	84	continue;
3f09df70	85	unlock_kernel();
888e694c	86	status = nfs4_lock_delegation_recall(state, fl);
d5122201	87	if (status < 0)
3f09df70 TM	88	goto out;
3f09df70 TM	89	lock_kernel();
888e694c	90	}
3f09df70 TM	91	unlock_kernel();
3f09df70 TM	92	out:
888e694c TM	93	return status;
	94	}
	95
d18cc1fd	96	static int nfs_delegation_claim_opens(struct inode inode, const nfs4_stateid stateid)
1da177e4 LT	97	{
	98	struct nfs_inode *nfsi = NFS_I(inode);
	99	struct nfs_open_context *ctx;
	100	struct nfs4_state *state;
888e694c	101	int err;
1da177e4 LT	102
	103	again:
	104	spin_lock(&inode->i_lock);
	105	list_for_each_entry(ctx, &nfsi->open_files, list) {
	106	state = ctx->state;
	107	if (state == NULL)
	108	continue;
	109	if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
	110	continue;
90163027 TM	111	if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
90163027 TM	112	continue;
1da177e4 LT	113	get_nfs_open_context(ctx);
1da177e4 LT	114	spin_unlock(&inode->i_lock);
13437e12	115	err = nfs4_open_delegation_recall(ctx, state, stateid);
888e694c TM	116	if (err >= 0)
888e694c TM	117	err = nfs_delegation_claim_locks(ctx, state);
1da177e4	118	put_nfs_open_context(ctx);
888e694c	119	if (err != 0)
d18cc1fd	120	return err;
1da177e4 LT	121	goto again;
	122	}
	123	spin_unlock(&inode->i_lock);
d18cc1fd	124	return 0;
1da177e4 LT	125	}
	126
	127	/*
	128	* Set up a delegation on an inode
	129	*/
	130	void nfs_inode_reclaim_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	131	{
	132	struct nfs_delegation *delegation = NFS_I(inode)->delegation;
05c88bab	133	struct rpc_cred *oldcred;
1da177e4 LT	134
	135	if (delegation == NULL)
	136	return;
	137	memcpy(delegation->stateid.data, res->delegation.data,
	138	sizeof(delegation->stateid.data));
	139	delegation->type = res->delegation_type;
	140	delegation->maxsize = res->maxsize;
05c88bab	141	oldcred = delegation->cred;
1da177e4	142	delegation->cred = get_rpccred(cred);
15c831bf	143	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1da177e4 LT	144	NFS_I(inode)->delegation_state = delegation->type;
1da177e4 LT	145	smp_wmb();
05c88bab	146	put_rpccred(oldcred);
1da177e4 LT	147	}
1da177e4 LT	148
57bfa891 TM	149	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
	150	{
	151	int res = 0;
	152
	153	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	154	nfs_free_delegation(delegation);
	155	return res;
	156	}
	157
86e89489 TM	158	static struct inode nfs_delegation_grab_inode(struct nfs_delegation delegation)
	159	{
	160	struct inode *inode = NULL;
	161
	162	spin_lock(&delegation->lock);
	163	if (delegation->inode != NULL)
	164	inode = igrab(delegation->inode);
	165	spin_unlock(&delegation->lock);
	166	return inode;
	167	}
	168
57bfa891 TM	169	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	170	{
	171	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
	172
	173	if (delegation == NULL)
	174	goto nomatch;
34310430	175	spin_lock(&delegation->lock);
57bfa891 TM	176	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
57bfa891 TM	177	sizeof(delegation->stateid.data)) != 0)
34310430	178	goto nomatch_unlock;
57bfa891	179	list_del_rcu(&delegation->super_list);
86e89489	180	delegation->inode = NULL;
57bfa891 TM	181	nfsi->delegation_state = 0;
57bfa891 TM	182	rcu_assign_pointer(nfsi->delegation, NULL);
34310430	183	spin_unlock(&delegation->lock);
57bfa891	184	return delegation;
34310430 TM	185	nomatch_unlock:
34310430 TM	186	spin_unlock(&delegation->lock);
57bfa891 TM	187	nomatch:
	188	return NULL;
	189	}
	190
1da177e4 LT	191	/*
	192	* Set up a delegation on an inode
	193	*/
	194	int nfs_inode_set_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	195	{
7539bbab	196	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	197	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	198	struct nfs_delegation *delegation;
57bfa891	199	struct nfs_delegation *freeme = NULL;
1da177e4 LT	200	int status = 0;
1da177e4 LT	201
f52720ca	202	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
1da177e4 LT	203	if (delegation == NULL)
	204	return -ENOMEM;
	205	memcpy(delegation->stateid.data, res->delegation.data,
	206	sizeof(delegation->stateid.data));
	207	delegation->type = res->delegation_type;
	208	delegation->maxsize = res->maxsize;
beb2a5ec	209	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	210	delegation->cred = get_rpccred(cred);
1da177e4 LT	211	delegation->inode = inode;
b7391f44	212	delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
34310430	213	spin_lock_init(&delegation->lock);
1da177e4 LT	214
1da177e4 LT	215	spin_lock(&clp->cl_lock);
57bfa891	216	if (rcu_dereference(nfsi->delegation) != NULL) {
1da177e4	217	if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
57bfa891 TM	218	sizeof(delegation->stateid)) == 0 &&
	219	delegation->type == nfsi->delegation->type) {
	220	goto out;
1da177e4	221	}
57bfa891 TM	222	/*
	223	* Deal with broken servers that hand out two
	224	* delegations for the same file.
	225	*/
	226	dfprintk(FILE, "%s: server %s handed out "
	227	"a duplicate delegation!\n",
3110ff80	228	__func__, clp->cl_hostname);
57bfa891 TM	229	if (delegation->type <= nfsi->delegation->type) {
	230	freeme = delegation;
	231	delegation = NULL;
	232	goto out;
	233	}
	234	freeme = nfs_detach_delegation_locked(nfsi, NULL);
1da177e4	235	}
57bfa891 TM	236	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	237	nfsi->delegation_state = delegation->type;
	238	rcu_assign_pointer(nfsi->delegation, delegation);
	239	delegation = NULL;
412c77ce TM	240
	241	/* Ensure we revalidate the attributes and page cache! */
	242	spin_lock(&inode->i_lock);
	243	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	244	spin_unlock(&inode->i_lock);
	245
57bfa891	246	out:
1da177e4	247	spin_unlock(&clp->cl_lock);
603c83da TM	248	if (delegation != NULL)
603c83da TM	249	nfs_free_delegation(delegation);
57bfa891 TM	250	if (freeme != NULL)
57bfa891 TM	251	nfs_do_return_delegation(inode, freeme, 0);
1da177e4 LT	252	return status;
	253	}
	254
1da177e4 LT	255	/* Sync all data to disk upon delegation return */
	256	static void nfs_msync_inode(struct inode *inode)
	257	{
	258	filemap_fdatawrite(inode->i_mapping);
	259	nfs_wb_all(inode);
	260	filemap_fdatawait(inode->i_mapping);
	261	}
	262
	263	/*
	264	* Basic procedure for returning a delegation to the server
	265	*/
d18cc1fd	266	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
1da177e4	267	{
1da177e4	268	struct nfs_inode *nfsi = NFS_I(inode);
d18cc1fd	269	int err;
1da177e4	270
3f09df70 TM	271	/*
	272	* Guard against new delegated open/lock/unlock calls and against
	273	* state recovery
	274	*/
1da177e4	275	down_write(&nfsi->rwsem);
d18cc1fd	276	err = nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4	277	up_write(&nfsi->rwsem);
d18cc1fd TM	278	if (err)
d18cc1fd TM	279	goto out;
1da177e4	280
d18cc1fd TM	281	err = nfs_do_return_delegation(inode, delegation, issync);
	282	out:
	283	return err;
90163027 TM	284	}
90163027 TM	285
515d8611 TM	286	/*
	287	* Return all delegations that have been marked for return
	288	*/
d18cc1fd	289	int nfs_client_return_marked_delegations(struct nfs_client *clp)
515d8611 TM	290	{
	291	struct nfs_delegation *delegation;
	292	struct inode *inode;
d18cc1fd	293	int err = 0;
515d8611 TM	294
	295	restart:
	296	rcu_read_lock();
	297	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	298	if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
	299	continue;
	300	inode = nfs_delegation_grab_inode(delegation);
	301	if (inode == NULL)
	302	continue;
	303	spin_lock(&clp->cl_lock);
	304	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
	305	spin_unlock(&clp->cl_lock);
	306	rcu_read_unlock();
d18cc1fd TM	307	if (delegation != NULL) {
	308	filemap_flush(inode->i_mapping);
	309	err = __nfs_inode_return_delegation(inode, delegation, 0);
	310	}
515d8611	311	iput(inode);
d18cc1fd TM	312	if (!err)
	313	goto restart;
	314	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	315	return err;
515d8611 TM	316	}
515d8611 TM	317	rcu_read_unlock();
d18cc1fd	318	return 0;
515d8611 TM	319	}
515d8611 TM	320
e6f81075 TM	321	/*
	322	* This function returns the delegation without reclaiming opens
	323	* or protecting against delegation reclaims.
	324	* It is therefore really only safe to be called from
	325	* nfs4_clear_inode()
	326	*/
	327	void nfs_inode_return_delegation_noreclaim(struct inode *inode)
	328	{
	329	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	330	struct nfs_inode *nfsi = NFS_I(inode);
	331	struct nfs_delegation *delegation;
	332
	333	if (rcu_dereference(nfsi->delegation) != NULL) {
	334	spin_lock(&clp->cl_lock);
	335	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	336	spin_unlock(&clp->cl_lock);
	337	if (delegation != NULL)
	338	nfs_do_return_delegation(inode, delegation, 0);
	339	}
	340	}
	341
90163027 TM	342	int nfs_inode_return_delegation(struct inode *inode)
	343	{
	344	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	345	struct nfs_inode *nfsi = NFS_I(inode);
	346	struct nfs_delegation *delegation;
	347	int err = 0;
	348
8383e460	349	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	350	spin_lock(&clp->cl_lock);
	351	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	352	spin_unlock(&clp->cl_lock);
d18cc1fd TM	353	if (delegation != NULL) {
	354	nfs_msync_inode(inode);
	355	err = __nfs_inode_return_delegation(inode, delegation, 1);
	356	}
90163027 TM	357	}
90163027 TM	358	return err;
1da177e4 LT	359	}
1da177e4 LT	360
6411bd4a TM	361	static void nfs_mark_return_delegation(struct nfs_client clp, struct nfs_delegation delegation)
	362	{
	363	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
	364	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	365	}
	366
1da177e4 LT	367	/*
	368	* Return all delegations associated to a super block
	369	*/
515d8611	370	void nfs_super_return_all_delegations(struct super_block *sb)
1da177e4	371	{
7539bbab	372	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4	373	struct nfs_delegation *delegation;
1da177e4 LT	374
	375	if (clp == NULL)
	376	return;
8383e460 TM	377	rcu_read_lock();
8383e460 TM	378	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	379	spin_lock(&delegation->lock);
86e89489 TM	380	if (delegation->inode != NULL && delegation->inode->i_sb == sb)
515d8611	381	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
86e89489	382	spin_unlock(&delegation->lock);
1da177e4	383	}
8383e460	384	rcu_read_unlock();
d18cc1fd TM	385	if (nfs_client_return_marked_delegations(clp) != 0)
d18cc1fd TM	386	nfs4_schedule_state_manager(clp);
515d8611 TM	387	}
515d8611 TM	388
c79571a5 AB	389	static
c79571a5 AB	390	void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
515d8611 TM	391	{
	392	struct nfs_delegation *delegation;
	393
	394	rcu_read_lock();
707fb4b3	395	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
c79571a5 AB	396	if ((delegation->type == (FMODE_READ\|FMODE_WRITE)) && !(flags & FMODE_WRITE))
	397	continue;
	398	if (delegation->type & flags)
	399	nfs_mark_return_delegation(clp, delegation);
707fb4b3	400	}
515d8611	401	rcu_read_unlock();
1da177e4 LT	402	}
1da177e4 LT	403
c79571a5 AB	404	static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
	405	{
	406	nfs_client_mark_return_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	407	}
	408
b0d3ded1	409	static void nfs_delegation_run_state_manager(struct nfs_client *clp)
58d9714a	410	{
b0d3ded1 TM	411	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
b0d3ded1 TM	412	nfs4_schedule_state_manager(clp);
58d9714a TM	413	}
58d9714a TM	414
31f09607	415	void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
58d9714a	416	{
c79571a5	417	nfs_client_mark_return_all_delegation_types(clp, flags);
b0d3ded1	418	nfs_delegation_run_state_manager(clp);
58d9714a TM	419	}
58d9714a TM	420
c79571a5 AB	421	void nfs_expire_all_delegations(struct nfs_client *clp)
	422	{
	423	nfs_expire_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	424	}
	425
1da177e4 LT	426	/*
	427	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	428	*/
adfa6f98	429	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4	430	{
1da177e4 LT	431	if (clp == NULL)
1da177e4 LT	432	return;
707fb4b3	433	nfs_client_mark_return_all_delegations(clp);
1da177e4 LT	434	}
1da177e4 LT	435
b7391f44 TM	436	static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
	437	{
	438	struct nfs_delegation *delegation;
	439
	440	rcu_read_lock();
	441	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	442	if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
	443	continue;
b4a6f496	444	nfs_mark_return_delegation(clp, delegation);
b7391f44 TM	445	}
	446	rcu_read_unlock();
	447	}
	448
	449	void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
	450	{
	451	nfs_client_mark_return_unreferenced_delegations(clp);
	452	nfs_delegation_run_state_manager(clp);
	453	}
	454
1da177e4 LT	455	/*
	456	* Asynchronous delegation recall!
	457	*/
2597641d AB	458	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid,
	459	int (validate_stateid)(struct nfs_delegation delegation,
	460	const nfs4_stateid *stateid))
1da177e4	461	{
6411bd4a TM	462	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
6411bd4a TM	463	struct nfs_delegation *delegation;
1da177e4	464
6411bd4a TM	465	rcu_read_lock();
6411bd4a TM	466	delegation = rcu_dereference(NFS_I(inode)->delegation);
2597641d AB	467
2597641d AB	468	if (!validate_stateid(delegation, stateid)) {
6411bd4a TM	469	rcu_read_unlock();
	470	return -ENOENT;
	471	}
2597641d	472
6411bd4a TM	473	nfs_mark_return_delegation(clp, delegation);
	474	rcu_read_unlock();
	475	nfs_delegation_run_state_manager(clp);
	476	return 0;
1da177e4 LT	477	}
	478
	479	/*
	480	* Retrieve the inode associated with a delegation
	481	*/
adfa6f98	482	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	483	{
	484	struct nfs_delegation *delegation;
	485	struct inode *res = NULL;
8383e460 TM	486	rcu_read_lock();
8383e460 TM	487	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	488	spin_lock(&delegation->lock);
	489	if (delegation->inode != NULL &&
	490	nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1da177e4	491	res = igrab(delegation->inode);
1da177e4	492	}
86e89489 TM	493	spin_unlock(&delegation->lock);
	494	if (res != NULL)
	495	break;
1da177e4	496	}
8383e460	497	rcu_read_unlock();
1da177e4 LT	498	return res;
	499	}
	500
	501	/*
	502	* Mark all delegations as needing to be reclaimed
	503	*/
adfa6f98	504	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	505	{
1da177e4 LT	506	struct nfs_delegation *delegation;
8383e460 TM	507	rcu_read_lock();
8383e460 TM	508	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
15c831bf	509	set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
8383e460	510	rcu_read_unlock();
1da177e4 LT	511	}
	512
	513	/*
	514	* Reap all unclaimed delegations after reboot recovery is done
	515	*/
adfa6f98	516	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	517	{
8383e460	518	struct nfs_delegation *delegation;
86e89489	519	struct inode *inode;
8383e460 TM	520	restart:
	521	rcu_read_lock();
	522	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
15c831bf	523	if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
1da177e4	524	continue;
86e89489 TM	525	inode = nfs_delegation_grab_inode(delegation);
	526	if (inode == NULL)
	527	continue;
8383e460	528	spin_lock(&clp->cl_lock);
86e89489	529	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
8383e460 TM	530	spin_unlock(&clp->cl_lock);
	531	rcu_read_unlock();
	532	if (delegation != NULL)
905f8d16	533	nfs_free_delegation(delegation);
86e89489	534	iput(inode);
8383e460	535	goto restart;
1da177e4	536	}
8383e460	537	rcu_read_unlock();
1da177e4	538	}
3e4f6290 TM	539
	540	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	541	{
3e4f6290 TM	542	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	543	struct nfs_delegation *delegation;
8383e460	544	int ret = 0;
3e4f6290	545
8383e460 TM	546	rcu_read_lock();
8383e460 TM	547	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	548	if (delegation != NULL) {
3e4f6290 TM	549	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	550	ret = 1;
3e4f6290	551	}
8383e460 TM	552	rcu_read_unlock();
8383e460 TM	553	return ret;
3e4f6290	554	}