[linux-2.6-block.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/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>
405f5571	13	#include <linux/smp_lock.h>
1da177e4 LT	14	#include <linux/spinlock.h>
	15
	16	#include <linux/nfs4.h>
	17	#include <linux/nfs_fs.h>
	18	#include <linux/nfs_xdr.h>
	19
4ce79717	20	#include "nfs4_fs.h"
1da177e4	21	#include "delegation.h"
24c8dbbb	22	#include "internal.h"
1da177e4	23
905f8d16	24	static void nfs_do_free_delegation(struct nfs_delegation *delegation)
1da177e4	25	{
1da177e4 LT	26	kfree(delegation);
	27	}
	28
8383e460 TM	29	static void nfs_free_delegation_callback(struct rcu_head *head)
	30	{
	31	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
	32
905f8d16 TM	33	nfs_do_free_delegation(delegation);
	34	}
	35
	36	static void nfs_free_delegation(struct nfs_delegation *delegation)
	37	{
	38	struct rpc_cred *cred;
	39
	40	cred = rcu_dereference(delegation->cred);
	41	rcu_assign_pointer(delegation->cred, NULL);
	42	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	43	if (cred)
	44	put_rpccred(cred);
8383e460 TM	45	}
8383e460 TM	46
b7391f44 TM	47	void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
	48	{
	49	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
	50	}
	51
bd7bf9d5	52	int nfs_have_delegation(struct inode *inode, fmode_t flags)
b7391f44 TM	53	{
	54	struct nfs_delegation *delegation;
	55	int ret = 0;
	56
	57	flags &= FMODE_READ\|FMODE_WRITE;
	58	rcu_read_lock();
	59	delegation = rcu_dereference(NFS_I(inode)->delegation);
	60	if (delegation != NULL && (delegation->type & flags) == flags) {
	61	nfs_mark_delegation_referenced(delegation);
	62	ret = 1;
	63	}
	64	rcu_read_unlock();
	65	return ret;
	66	}
	67
888e694c TM	68	static int nfs_delegation_claim_locks(struct nfs_open_context ctx, struct nfs4_state state)
	69	{
	70	struct inode *inode = state->inode;
	71	struct file_lock *fl;
d5122201	72	int status = 0;
888e694c	73
3f09df70 TM	74	if (inode->i_flock == NULL)
	75	goto out;
	76
	77	/* Protect inode->i_flock using the BKL */
	78	lock_kernel();
90dc7d27	79	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
888e694c TM	80	if (!(fl->fl_flags & (FL_POSIX\|FL_FLOCK)))
888e694c TM	81	continue;
cd3758e3	82	if (nfs_file_open_context(fl->fl_file) != ctx)
888e694c	83	continue;
3f09df70	84	unlock_kernel();
888e694c	85	status = nfs4_lock_delegation_recall(state, fl);
d5122201	86	if (status < 0)
3f09df70 TM	87	goto out;
3f09df70 TM	88	lock_kernel();
888e694c	89	}
3f09df70 TM	90	unlock_kernel();
3f09df70 TM	91	out:
888e694c TM	92	return status;
	93	}
	94
d18cc1fd	95	static int nfs_delegation_claim_opens(struct inode inode, const nfs4_stateid stateid)
1da177e4 LT	96	{
	97	struct nfs_inode *nfsi = NFS_I(inode);
	98	struct nfs_open_context *ctx;
	99	struct nfs4_state *state;
888e694c	100	int err;
1da177e4 LT	101
	102	again:
	103	spin_lock(&inode->i_lock);
	104	list_for_each_entry(ctx, &nfsi->open_files, list) {
	105	state = ctx->state;
	106	if (state == NULL)
	107	continue;
	108	if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
	109	continue;
90163027 TM	110	if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
90163027 TM	111	continue;
1da177e4 LT	112	get_nfs_open_context(ctx);
1da177e4 LT	113	spin_unlock(&inode->i_lock);
13437e12	114	err = nfs4_open_delegation_recall(ctx, state, stateid);
888e694c TM	115	if (err >= 0)
888e694c TM	116	err = nfs_delegation_claim_locks(ctx, state);
1da177e4	117	put_nfs_open_context(ctx);
888e694c	118	if (err != 0)
d18cc1fd	119	return err;
1da177e4 LT	120	goto again;
	121	}
	122	spin_unlock(&inode->i_lock);
d18cc1fd	123	return 0;
1da177e4 LT	124	}
	125
	126	/*
	127	* Set up a delegation on an inode
	128	*/
	129	void nfs_inode_reclaim_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	130	{
	131	struct nfs_delegation *delegation = NFS_I(inode)->delegation;
05c88bab	132	struct rpc_cred *oldcred;
1da177e4 LT	133
	134	if (delegation == NULL)
	135	return;
	136	memcpy(delegation->stateid.data, res->delegation.data,
	137	sizeof(delegation->stateid.data));
	138	delegation->type = res->delegation_type;
	139	delegation->maxsize = res->maxsize;
05c88bab	140	oldcred = delegation->cred;
1da177e4	141	delegation->cred = get_rpccred(cred);
15c831bf	142	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1da177e4 LT	143	NFS_I(inode)->delegation_state = delegation->type;
1da177e4 LT	144	smp_wmb();
05c88bab	145	put_rpccred(oldcred);
1da177e4 LT	146	}
1da177e4 LT	147
57bfa891 TM	148	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
	149	{
	150	int res = 0;
	151
	152	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	153	nfs_free_delegation(delegation);
	154	return res;
	155	}
	156
86e89489 TM	157	static struct inode nfs_delegation_grab_inode(struct nfs_delegation delegation)
	158	{
	159	struct inode *inode = NULL;
	160
	161	spin_lock(&delegation->lock);
	162	if (delegation->inode != NULL)
	163	inode = igrab(delegation->inode);
	164	spin_unlock(&delegation->lock);
	165	return inode;
	166	}
	167
57bfa891 TM	168	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	169	{
	170	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
	171
	172	if (delegation == NULL)
	173	goto nomatch;
34310430	174	spin_lock(&delegation->lock);
57bfa891 TM	175	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
57bfa891 TM	176	sizeof(delegation->stateid.data)) != 0)
34310430	177	goto nomatch_unlock;
57bfa891	178	list_del_rcu(&delegation->super_list);
86e89489	179	delegation->inode = NULL;
57bfa891 TM	180	nfsi->delegation_state = 0;
57bfa891 TM	181	rcu_assign_pointer(nfsi->delegation, NULL);
34310430	182	spin_unlock(&delegation->lock);
57bfa891	183	return delegation;
34310430 TM	184	nomatch_unlock:
34310430 TM	185	spin_unlock(&delegation->lock);
57bfa891 TM	186	nomatch:
	187	return NULL;
	188	}
	189
1da177e4 LT	190	/*
	191	* Set up a delegation on an inode
	192	*/
	193	int nfs_inode_set_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	194	{
7539bbab	195	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	196	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	197	struct nfs_delegation *delegation;
57bfa891	198	struct nfs_delegation *freeme = NULL;
1da177e4 LT	199	int status = 0;
1da177e4 LT	200
f52720ca	201	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
1da177e4 LT	202	if (delegation == NULL)
	203	return -ENOMEM;
	204	memcpy(delegation->stateid.data, res->delegation.data,
	205	sizeof(delegation->stateid.data));
	206	delegation->type = res->delegation_type;
	207	delegation->maxsize = res->maxsize;
beb2a5ec	208	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	209	delegation->cred = get_rpccred(cred);
1da177e4 LT	210	delegation->inode = inode;
b7391f44	211	delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
34310430	212	spin_lock_init(&delegation->lock);
1da177e4 LT	213
1da177e4 LT	214	spin_lock(&clp->cl_lock);
57bfa891	215	if (rcu_dereference(nfsi->delegation) != NULL) {
1da177e4	216	if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
57bfa891 TM	217	sizeof(delegation->stateid)) == 0 &&
	218	delegation->type == nfsi->delegation->type) {
	219	goto out;
1da177e4	220	}
57bfa891 TM	221	/*
	222	* Deal with broken servers that hand out two
	223	* delegations for the same file.
	224	*/
	225	dfprintk(FILE, "%s: server %s handed out "
	226	"a duplicate delegation!\n",
3110ff80	227	__func__, clp->cl_hostname);
57bfa891 TM	228	if (delegation->type <= nfsi->delegation->type) {
	229	freeme = delegation;
	230	delegation = NULL;
	231	goto out;
	232	}
	233	freeme = nfs_detach_delegation_locked(nfsi, NULL);
1da177e4	234	}
57bfa891 TM	235	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	236	nfsi->delegation_state = delegation->type;
	237	rcu_assign_pointer(nfsi->delegation, delegation);
	238	delegation = NULL;
412c77ce TM	239
	240	/* Ensure we revalidate the attributes and page cache! */
	241	spin_lock(&inode->i_lock);
	242	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	243	spin_unlock(&inode->i_lock);
	244
57bfa891	245	out:
1da177e4	246	spin_unlock(&clp->cl_lock);
603c83da TM	247	if (delegation != NULL)
603c83da TM	248	nfs_free_delegation(delegation);
57bfa891 TM	249	if (freeme != NULL)
57bfa891 TM	250	nfs_do_return_delegation(inode, freeme, 0);
1da177e4 LT	251	return status;
	252	}
	253
1da177e4 LT	254	/* Sync all data to disk upon delegation return */
	255	static void nfs_msync_inode(struct inode *inode)
	256	{
	257	filemap_fdatawrite(inode->i_mapping);
	258	nfs_wb_all(inode);
	259	filemap_fdatawait(inode->i_mapping);
	260	}
	261
	262	/*
	263	* Basic procedure for returning a delegation to the server
	264	*/
d18cc1fd	265	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
1da177e4	266	{
1da177e4	267	struct nfs_inode *nfsi = NFS_I(inode);
d18cc1fd	268	int err;
1da177e4	269
3f09df70 TM	270	/*
	271	* Guard against new delegated open/lock/unlock calls and against
	272	* state recovery
	273	*/
1da177e4	274	down_write(&nfsi->rwsem);
d18cc1fd	275	err = nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4	276	up_write(&nfsi->rwsem);
d18cc1fd TM	277	if (err)
d18cc1fd TM	278	goto out;
1da177e4	279
d18cc1fd TM	280	err = nfs_do_return_delegation(inode, delegation, issync);
	281	out:
	282	return err;
90163027 TM	283	}
90163027 TM	284
515d8611 TM	285	/*
	286	* Return all delegations that have been marked for return
	287	*/
d18cc1fd	288	int nfs_client_return_marked_delegations(struct nfs_client *clp)
515d8611 TM	289	{
	290	struct nfs_delegation *delegation;
	291	struct inode *inode;
d18cc1fd	292	int err = 0;
515d8611 TM	293
	294	restart:
	295	rcu_read_lock();
	296	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	297	if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
	298	continue;
	299	inode = nfs_delegation_grab_inode(delegation);
	300	if (inode == NULL)
	301	continue;
	302	spin_lock(&clp->cl_lock);
	303	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
	304	spin_unlock(&clp->cl_lock);
	305	rcu_read_unlock();
d18cc1fd TM	306	if (delegation != NULL) {
	307	filemap_flush(inode->i_mapping);
	308	err = __nfs_inode_return_delegation(inode, delegation, 0);
	309	}
515d8611	310	iput(inode);
d18cc1fd TM	311	if (!err)
	312	goto restart;
	313	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	314	return err;
515d8611 TM	315	}
515d8611 TM	316	rcu_read_unlock();
d18cc1fd	317	return 0;
515d8611 TM	318	}
515d8611 TM	319
e6f81075 TM	320	/*
	321	* This function returns the delegation without reclaiming opens
	322	* or protecting against delegation reclaims.
	323	* It is therefore really only safe to be called from
	324	* nfs4_clear_inode()
	325	*/
	326	void nfs_inode_return_delegation_noreclaim(struct inode *inode)
	327	{
	328	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	329	struct nfs_inode *nfsi = NFS_I(inode);
	330	struct nfs_delegation *delegation;
	331
	332	if (rcu_dereference(nfsi->delegation) != NULL) {
	333	spin_lock(&clp->cl_lock);
	334	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	335	spin_unlock(&clp->cl_lock);
	336	if (delegation != NULL)
	337	nfs_do_return_delegation(inode, delegation, 0);
	338	}
	339	}
	340
90163027 TM	341	int nfs_inode_return_delegation(struct inode *inode)
	342	{
	343	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	344	struct nfs_inode *nfsi = NFS_I(inode);
	345	struct nfs_delegation *delegation;
	346	int err = 0;
	347
8383e460	348	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	349	spin_lock(&clp->cl_lock);
	350	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	351	spin_unlock(&clp->cl_lock);
d18cc1fd TM	352	if (delegation != NULL) {
	353	nfs_msync_inode(inode);
	354	err = __nfs_inode_return_delegation(inode, delegation, 1);
	355	}
90163027 TM	356	}
90163027 TM	357	return err;
1da177e4 LT	358	}
1da177e4 LT	359
6411bd4a TM	360	static void nfs_mark_return_delegation(struct nfs_client clp, struct nfs_delegation delegation)
	361	{
	362	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
	363	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	364	}
	365
1da177e4 LT	366	/*
	367	* Return all delegations associated to a super block
	368	*/
515d8611	369	void nfs_super_return_all_delegations(struct super_block *sb)
1da177e4	370	{
7539bbab	371	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4	372	struct nfs_delegation *delegation;
1da177e4 LT	373
	374	if (clp == NULL)
	375	return;
8383e460 TM	376	rcu_read_lock();
8383e460 TM	377	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	378	spin_lock(&delegation->lock);
86e89489 TM	379	if (delegation->inode != NULL && delegation->inode->i_sb == sb)
515d8611	380	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
86e89489	381	spin_unlock(&delegation->lock);
1da177e4	382	}
8383e460	383	rcu_read_unlock();
d18cc1fd TM	384	if (nfs_client_return_marked_delegations(clp) != 0)
d18cc1fd TM	385	nfs4_schedule_state_manager(clp);
515d8611 TM	386	}
515d8611 TM	387
c79571a5 AB	388	static
c79571a5 AB	389	void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
515d8611 TM	390	{
	391	struct nfs_delegation *delegation;
	392
	393	rcu_read_lock();
707fb4b3	394	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
c79571a5 AB	395	if ((delegation->type == (FMODE_READ\|FMODE_WRITE)) && !(flags & FMODE_WRITE))
	396	continue;
	397	if (delegation->type & flags)
	398	nfs_mark_return_delegation(clp, delegation);
707fb4b3	399	}
515d8611	400	rcu_read_unlock();
1da177e4 LT	401	}
1da177e4 LT	402
c79571a5 AB	403	static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
	404	{
	405	nfs_client_mark_return_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	406	}
	407
b0d3ded1	408	static void nfs_delegation_run_state_manager(struct nfs_client *clp)
58d9714a	409	{
b0d3ded1 TM	410	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
b0d3ded1 TM	411	nfs4_schedule_state_manager(clp);
58d9714a TM	412	}
58d9714a TM	413
31f09607	414	void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
58d9714a	415	{
c79571a5	416	nfs_client_mark_return_all_delegation_types(clp, flags);
b0d3ded1	417	nfs_delegation_run_state_manager(clp);
58d9714a TM	418	}
58d9714a TM	419
c79571a5 AB	420	void nfs_expire_all_delegations(struct nfs_client *clp)
	421	{
	422	nfs_expire_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	423	}
	424
1da177e4 LT	425	/*
	426	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	427	*/
adfa6f98	428	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4	429	{
1da177e4 LT	430	if (clp == NULL)
1da177e4 LT	431	return;
707fb4b3	432	nfs_client_mark_return_all_delegations(clp);
1da177e4 LT	433	}
1da177e4 LT	434
b7391f44 TM	435	static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
	436	{
	437	struct nfs_delegation *delegation;
	438
	439	rcu_read_lock();
	440	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	441	if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
	442	continue;
b4a6f496	443	nfs_mark_return_delegation(clp, delegation);
b7391f44 TM	444	}
	445	rcu_read_unlock();
	446	}
	447
	448	void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
	449	{
	450	nfs_client_mark_return_unreferenced_delegations(clp);
	451	nfs_delegation_run_state_manager(clp);
	452	}
	453
1da177e4 LT	454	/*
	455	* Asynchronous delegation recall!
	456	*/
2597641d AB	457	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid,
	458	int (validate_stateid)(struct nfs_delegation delegation,
	459	const nfs4_stateid *stateid))
1da177e4	460	{
6411bd4a TM	461	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
6411bd4a TM	462	struct nfs_delegation *delegation;
1da177e4	463
6411bd4a TM	464	rcu_read_lock();
6411bd4a TM	465	delegation = rcu_dereference(NFS_I(inode)->delegation);
2597641d AB	466
2597641d AB	467	if (!validate_stateid(delegation, stateid)) {
6411bd4a TM	468	rcu_read_unlock();
	469	return -ENOENT;
	470	}
2597641d	471
6411bd4a TM	472	nfs_mark_return_delegation(clp, delegation);
	473	rcu_read_unlock();
	474	nfs_delegation_run_state_manager(clp);
	475	return 0;
1da177e4 LT	476	}
	477
	478	/*
	479	* Retrieve the inode associated with a delegation
	480	*/
adfa6f98	481	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	482	{
	483	struct nfs_delegation *delegation;
	484	struct inode *res = NULL;
8383e460 TM	485	rcu_read_lock();
8383e460 TM	486	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	487	spin_lock(&delegation->lock);
	488	if (delegation->inode != NULL &&
	489	nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1da177e4	490	res = igrab(delegation->inode);
1da177e4	491	}
86e89489 TM	492	spin_unlock(&delegation->lock);
	493	if (res != NULL)
	494	break;
1da177e4	495	}
8383e460	496	rcu_read_unlock();
1da177e4 LT	497	return res;
	498	}
	499
	500	/*
	501	* Mark all delegations as needing to be reclaimed
	502	*/
adfa6f98	503	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	504	{
1da177e4 LT	505	struct nfs_delegation *delegation;
8383e460 TM	506	rcu_read_lock();
8383e460 TM	507	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
15c831bf	508	set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
8383e460	509	rcu_read_unlock();
1da177e4 LT	510	}
	511
	512	/*
	513	* Reap all unclaimed delegations after reboot recovery is done
	514	*/
adfa6f98	515	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	516	{
8383e460	517	struct nfs_delegation *delegation;
86e89489	518	struct inode *inode;
8383e460 TM	519	restart:
	520	rcu_read_lock();
	521	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
15c831bf	522	if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
1da177e4	523	continue;
86e89489 TM	524	inode = nfs_delegation_grab_inode(delegation);
	525	if (inode == NULL)
	526	continue;
8383e460	527	spin_lock(&clp->cl_lock);
86e89489	528	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
8383e460 TM	529	spin_unlock(&clp->cl_lock);
	530	rcu_read_unlock();
	531	if (delegation != NULL)
905f8d16	532	nfs_free_delegation(delegation);
86e89489	533	iput(inode);
8383e460	534	goto restart;
1da177e4	535	}
8383e460	536	rcu_read_unlock();
1da177e4	537	}
3e4f6290 TM	538
	539	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	540	{
3e4f6290 TM	541	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	542	struct nfs_delegation *delegation;
8383e460	543	int ret = 0;
3e4f6290	544
8383e460 TM	545	rcu_read_lock();
8383e460 TM	546	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	547	if (delegation != NULL) {
3e4f6290 TM	548	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	549	ret = 1;
3e4f6290	550	}
8383e460 TM	551	rcu_read_unlock();
8383e460 TM	552	return ret;
3e4f6290	553	}