[linux-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/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;
	struct rpc_cred *oldcred = NULL;

	rcu_read_lock();
	delegation = rcu_dereference(NFS_I(inode)->delegation);
	if (delegation != NULL) {
		spin_lock(&delegation->lock);
		if (delegation->inode != NULL) {
			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;
			spin_unlock(&delegation->lock);
			put_rpccred(oldcred);
			rcu_read_unlock();
		} else {
			/* We appear to have raced with a delegation return. */
			spin_unlock(&delegation->lock);
			rcu_read_unlock();
			nfs_inode_set_delegation(inode, cred, res);
		}
	} else {
		rcu_read_unlock();
	}
}

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	{
8f649c37 TM	132	struct nfs_delegation *delegation;
8f649c37 TM	133	struct rpc_cred *oldcred = NULL;
1da177e4	134
8f649c37 TM	135	rcu_read_lock();
	136	delegation = rcu_dereference(NFS_I(inode)->delegation);
	137	if (delegation != NULL) {
	138	spin_lock(&delegation->lock);
	139	if (delegation->inode != NULL) {
	140	memcpy(delegation->stateid.data, res->delegation.data,
	141	sizeof(delegation->stateid.data));
	142	delegation->type = res->delegation_type;
	143	delegation->maxsize = res->maxsize;
	144	oldcred = delegation->cred;
	145	delegation->cred = get_rpccred(cred);
	146	clear_bit(NFS_DELEGATION_NEED_RECLAIM,
	147	&delegation->flags);
	148	NFS_I(inode)->delegation_state = delegation->type;
	149	spin_unlock(&delegation->lock);
	150	put_rpccred(oldcred);
	151	rcu_read_unlock();
	152	} else {
	153	/* We appear to have raced with a delegation return. */
	154	spin_unlock(&delegation->lock);
	155	rcu_read_unlock();
	156	nfs_inode_set_delegation(inode, cred, res);
	157	}
	158	} else {
	159	rcu_read_unlock();
	160	}
1da177e4 LT	161	}
1da177e4 LT	162
57bfa891 TM	163	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
	164	{
	165	int res = 0;
	166
	167	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	168	nfs_free_delegation(delegation);
	169	return res;
	170	}
	171
86e89489 TM	172	static struct inode nfs_delegation_grab_inode(struct nfs_delegation delegation)
	173	{
	174	struct inode *inode = NULL;
	175
	176	spin_lock(&delegation->lock);
	177	if (delegation->inode != NULL)
	178	inode = igrab(delegation->inode);
	179	spin_unlock(&delegation->lock);
	180	return inode;
	181	}
	182
57bfa891 TM	183	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	184	{
	185	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
	186
	187	if (delegation == NULL)
	188	goto nomatch;
34310430	189	spin_lock(&delegation->lock);
57bfa891 TM	190	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
57bfa891 TM	191	sizeof(delegation->stateid.data)) != 0)
34310430	192	goto nomatch_unlock;
57bfa891	193	list_del_rcu(&delegation->super_list);
86e89489	194	delegation->inode = NULL;
57bfa891 TM	195	nfsi->delegation_state = 0;
57bfa891 TM	196	rcu_assign_pointer(nfsi->delegation, NULL);
34310430	197	spin_unlock(&delegation->lock);
57bfa891	198	return delegation;
34310430 TM	199	nomatch_unlock:
34310430 TM	200	spin_unlock(&delegation->lock);
57bfa891 TM	201	nomatch:
	202	return NULL;
	203	}
	204
1da177e4 LT	205	/*
	206	* Set up a delegation on an inode
	207	*/
	208	int nfs_inode_set_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	209	{
7539bbab	210	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	211	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	212	struct nfs_delegation *delegation;
57bfa891	213	struct nfs_delegation *freeme = NULL;
1da177e4 LT	214	int status = 0;
1da177e4 LT	215
f52720ca	216	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
1da177e4 LT	217	if (delegation == NULL)
	218	return -ENOMEM;
	219	memcpy(delegation->stateid.data, res->delegation.data,
	220	sizeof(delegation->stateid.data));
	221	delegation->type = res->delegation_type;
	222	delegation->maxsize = res->maxsize;
beb2a5ec	223	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	224	delegation->cred = get_rpccred(cred);
1da177e4 LT	225	delegation->inode = inode;
b7391f44	226	delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
34310430	227	spin_lock_init(&delegation->lock);
1da177e4 LT	228
1da177e4 LT	229	spin_lock(&clp->cl_lock);
57bfa891	230	if (rcu_dereference(nfsi->delegation) != NULL) {
1da177e4	231	if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
57bfa891 TM	232	sizeof(delegation->stateid)) == 0 &&
	233	delegation->type == nfsi->delegation->type) {
	234	goto out;
1da177e4	235	}
57bfa891 TM	236	/*
	237	* Deal with broken servers that hand out two
	238	* delegations for the same file.
	239	*/
	240	dfprintk(FILE, "%s: server %s handed out "
	241	"a duplicate delegation!\n",
3110ff80	242	__func__, clp->cl_hostname);
57bfa891 TM	243	if (delegation->type <= nfsi->delegation->type) {
	244	freeme = delegation;
	245	delegation = NULL;
	246	goto out;
	247	}
	248	freeme = nfs_detach_delegation_locked(nfsi, NULL);
1da177e4	249	}
57bfa891 TM	250	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	251	nfsi->delegation_state = delegation->type;
	252	rcu_assign_pointer(nfsi->delegation, delegation);
	253	delegation = NULL;
412c77ce TM	254
	255	/* Ensure we revalidate the attributes and page cache! */
	256	spin_lock(&inode->i_lock);
	257	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	258	spin_unlock(&inode->i_lock);
	259
57bfa891	260	out:
1da177e4	261	spin_unlock(&clp->cl_lock);
603c83da TM	262	if (delegation != NULL)
603c83da TM	263	nfs_free_delegation(delegation);
57bfa891 TM	264	if (freeme != NULL)
57bfa891 TM	265	nfs_do_return_delegation(inode, freeme, 0);
1da177e4 LT	266	return status;
	267	}
	268
1da177e4 LT	269	/* Sync all data to disk upon delegation return */
	270	static void nfs_msync_inode(struct inode *inode)
	271	{
	272	filemap_fdatawrite(inode->i_mapping);
	273	nfs_wb_all(inode);
	274	filemap_fdatawait(inode->i_mapping);
	275	}
	276
	277	/*
	278	* Basic procedure for returning a delegation to the server
	279	*/
d18cc1fd	280	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
1da177e4	281	{
1da177e4	282	struct nfs_inode *nfsi = NFS_I(inode);
d18cc1fd	283	int err;
1da177e4	284
3f09df70 TM	285	/*
	286	* Guard against new delegated open/lock/unlock calls and against
	287	* state recovery
	288	*/
1da177e4	289	down_write(&nfsi->rwsem);
d18cc1fd	290	err = nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4	291	up_write(&nfsi->rwsem);
d18cc1fd TM	292	if (err)
d18cc1fd TM	293	goto out;
1da177e4	294
d18cc1fd TM	295	err = nfs_do_return_delegation(inode, delegation, issync);
	296	out:
	297	return err;
90163027 TM	298	}
90163027 TM	299
515d8611 TM	300	/*
	301	* Return all delegations that have been marked for return
	302	*/
d18cc1fd	303	int nfs_client_return_marked_delegations(struct nfs_client *clp)
515d8611 TM	304	{
	305	struct nfs_delegation *delegation;
	306	struct inode *inode;
d18cc1fd	307	int err = 0;
515d8611 TM	308
	309	restart:
	310	rcu_read_lock();
	311	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	312	if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
	313	continue;
	314	inode = nfs_delegation_grab_inode(delegation);
	315	if (inode == NULL)
	316	continue;
	317	spin_lock(&clp->cl_lock);
	318	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
	319	spin_unlock(&clp->cl_lock);
	320	rcu_read_unlock();
d18cc1fd TM	321	if (delegation != NULL) {
	322	filemap_flush(inode->i_mapping);
	323	err = __nfs_inode_return_delegation(inode, delegation, 0);
	324	}
515d8611	325	iput(inode);
d18cc1fd TM	326	if (!err)
	327	goto restart;
	328	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	329	return err;
515d8611 TM	330	}
515d8611 TM	331	rcu_read_unlock();
d18cc1fd	332	return 0;
515d8611 TM	333	}
515d8611 TM	334
e6f81075 TM	335	/*
	336	* This function returns the delegation without reclaiming opens
	337	* or protecting against delegation reclaims.
	338	* It is therefore really only safe to be called from
	339	* nfs4_clear_inode()
	340	*/
	341	void nfs_inode_return_delegation_noreclaim(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
	347	if (rcu_dereference(nfsi->delegation) != NULL) {
	348	spin_lock(&clp->cl_lock);
	349	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	350	spin_unlock(&clp->cl_lock);
	351	if (delegation != NULL)
	352	nfs_do_return_delegation(inode, delegation, 0);
	353	}
	354	}
	355
90163027 TM	356	int nfs_inode_return_delegation(struct inode *inode)
	357	{
	358	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	359	struct nfs_inode *nfsi = NFS_I(inode);
	360	struct nfs_delegation *delegation;
	361	int err = 0;
	362
8383e460	363	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	364	spin_lock(&clp->cl_lock);
	365	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	366	spin_unlock(&clp->cl_lock);
d18cc1fd TM	367	if (delegation != NULL) {
	368	nfs_msync_inode(inode);
	369	err = __nfs_inode_return_delegation(inode, delegation, 1);
	370	}
90163027 TM	371	}
90163027 TM	372	return err;
1da177e4 LT	373	}
1da177e4 LT	374
6411bd4a TM	375	static void nfs_mark_return_delegation(struct nfs_client clp, struct nfs_delegation delegation)
	376	{
	377	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
	378	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	379	}
	380
1da177e4 LT	381	/*
	382	* Return all delegations associated to a super block
	383	*/
515d8611	384	void nfs_super_return_all_delegations(struct super_block *sb)
1da177e4	385	{
7539bbab	386	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4	387	struct nfs_delegation *delegation;
1da177e4 LT	388
	389	if (clp == NULL)
	390	return;
8383e460 TM	391	rcu_read_lock();
8383e460 TM	392	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	393	spin_lock(&delegation->lock);
86e89489 TM	394	if (delegation->inode != NULL && delegation->inode->i_sb == sb)
515d8611	395	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
86e89489	396	spin_unlock(&delegation->lock);
1da177e4	397	}
8383e460	398	rcu_read_unlock();
d18cc1fd TM	399	if (nfs_client_return_marked_delegations(clp) != 0)
d18cc1fd TM	400	nfs4_schedule_state_manager(clp);
515d8611 TM	401	}
515d8611 TM	402
c79571a5 AB	403	static
c79571a5 AB	404	void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
515d8611 TM	405	{
	406	struct nfs_delegation *delegation;
	407
	408	rcu_read_lock();
707fb4b3	409	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
c79571a5 AB	410	if ((delegation->type == (FMODE_READ\|FMODE_WRITE)) && !(flags & FMODE_WRITE))
	411	continue;
	412	if (delegation->type & flags)
	413	nfs_mark_return_delegation(clp, delegation);
707fb4b3	414	}
515d8611	415	rcu_read_unlock();
1da177e4 LT	416	}
1da177e4 LT	417
c79571a5 AB	418	static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
	419	{
	420	nfs_client_mark_return_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	421	}
	422
b0d3ded1	423	static void nfs_delegation_run_state_manager(struct nfs_client *clp)
58d9714a	424	{
b0d3ded1 TM	425	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
b0d3ded1 TM	426	nfs4_schedule_state_manager(clp);
58d9714a TM	427	}
58d9714a TM	428
31f09607	429	void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
58d9714a	430	{
c79571a5	431	nfs_client_mark_return_all_delegation_types(clp, flags);
b0d3ded1	432	nfs_delegation_run_state_manager(clp);
58d9714a TM	433	}
58d9714a TM	434
c79571a5 AB	435	void nfs_expire_all_delegations(struct nfs_client *clp)
	436	{
	437	nfs_expire_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	438	}
	439
1da177e4 LT	440	/*
	441	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	442	*/
adfa6f98	443	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4	444	{
1da177e4 LT	445	if (clp == NULL)
1da177e4 LT	446	return;
707fb4b3	447	nfs_client_mark_return_all_delegations(clp);
1da177e4 LT	448	}
1da177e4 LT	449
b7391f44 TM	450	static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
	451	{
	452	struct nfs_delegation *delegation;
	453
	454	rcu_read_lock();
	455	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	456	if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
	457	continue;
b4a6f496	458	nfs_mark_return_delegation(clp, delegation);
b7391f44 TM	459	}
	460	rcu_read_unlock();
	461	}
	462
	463	void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
	464	{
	465	nfs_client_mark_return_unreferenced_delegations(clp);
	466	nfs_delegation_run_state_manager(clp);
	467	}
	468
1da177e4 LT	469	/*
	470	* Asynchronous delegation recall!
	471	*/
2597641d AB	472	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid,
	473	int (validate_stateid)(struct nfs_delegation delegation,
	474	const nfs4_stateid *stateid))
1da177e4	475	{
6411bd4a TM	476	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
6411bd4a TM	477	struct nfs_delegation *delegation;
1da177e4	478
6411bd4a TM	479	rcu_read_lock();
6411bd4a TM	480	delegation = rcu_dereference(NFS_I(inode)->delegation);
2597641d AB	481
2597641d AB	482	if (!validate_stateid(delegation, stateid)) {
6411bd4a TM	483	rcu_read_unlock();
	484	return -ENOENT;
	485	}
2597641d	486
6411bd4a TM	487	nfs_mark_return_delegation(clp, delegation);
	488	rcu_read_unlock();
	489	nfs_delegation_run_state_manager(clp);
	490	return 0;
1da177e4 LT	491	}
	492
	493	/*
	494	* Retrieve the inode associated with a delegation
	495	*/
adfa6f98	496	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	497	{
	498	struct nfs_delegation *delegation;
	499	struct inode *res = NULL;
8383e460 TM	500	rcu_read_lock();
8383e460 TM	501	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	502	spin_lock(&delegation->lock);
	503	if (delegation->inode != NULL &&
	504	nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1da177e4	505	res = igrab(delegation->inode);
1da177e4	506	}
86e89489 TM	507	spin_unlock(&delegation->lock);
	508	if (res != NULL)
	509	break;
1da177e4	510	}
8383e460	511	rcu_read_unlock();
1da177e4 LT	512	return res;
	513	}
	514
	515	/*
	516	* Mark all delegations as needing to be reclaimed
	517	*/
adfa6f98	518	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	519	{
1da177e4 LT	520	struct nfs_delegation *delegation;
8383e460 TM	521	rcu_read_lock();
8383e460 TM	522	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
15c831bf	523	set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
8383e460	524	rcu_read_unlock();
1da177e4 LT	525	}
	526
	527	/*
	528	* Reap all unclaimed delegations after reboot recovery is done
	529	*/
adfa6f98	530	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	531	{
8383e460	532	struct nfs_delegation *delegation;
86e89489	533	struct inode *inode;
8383e460 TM	534	restart:
	535	rcu_read_lock();
	536	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
15c831bf	537	if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
1da177e4	538	continue;
86e89489 TM	539	inode = nfs_delegation_grab_inode(delegation);
	540	if (inode == NULL)
	541	continue;
8383e460	542	spin_lock(&clp->cl_lock);
86e89489	543	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
8383e460 TM	544	spin_unlock(&clp->cl_lock);
	545	rcu_read_unlock();
	546	if (delegation != NULL)
905f8d16	547	nfs_free_delegation(delegation);
86e89489	548	iput(inode);
8383e460	549	goto restart;
1da177e4	550	}
8383e460	551	rcu_read_unlock();
1da177e4	552	}
3e4f6290 TM	553
	554	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	555	{
3e4f6290 TM	556	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	557	struct nfs_delegation *delegation;
8383e460	558	int ret = 0;
3e4f6290	559
8383e460 TM	560	rcu_read_lock();
8383e460 TM	561	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	562	if (delegation != NULL) {
3e4f6290 TM	563	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	564	ret = 1;
3e4f6290	565	}
8383e460 TM	566	rcu_read_unlock();
8383e460 TM	567	return ret;
3e4f6290	568	}