[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)
{
	if (delegation->cred)
		put_rpccred(delegation->cred);
	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)
{
	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
}

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 file locks lock */
	lock_flocks();
	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_flocks();
		status = nfs4_lock_delegation_recall(state, fl);
		if (status < 0)
			goto out;
		lock_flocks();
	}
	unlock_flocks();
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_client *clp)
{
	struct nfs_delegation *delegation =
		rcu_dereference_protected(nfsi->delegation,
					  lockdep_is_held(&clp->cl_lock));

	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, *old_delegation;
	struct nfs_delegation *freeme = NULL;
	int status = 0;

	delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
	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);
	old_delegation = rcu_dereference_protected(nfsi->delegation,
						   lockdep_is_held(&clp->cl_lock));
	if (old_delegation != NULL) {
		if (memcmp(&delegation->stateid, &old_delegation->stateid,
					sizeof(old_delegation->stateid)) == 0 &&
				delegation->type == old_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 <= old_delegation->type) {
			freeme = delegation;
			delegation = NULL;
			goto out;
		}
		freeme = nfs_detach_delegation_locked(nfsi, NULL, clp);
	}
	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;
}

/*
 * 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, clp);
		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_access_pointer(nfsi->delegation) != NULL) {
		spin_lock(&clp->cl_lock);
		delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
		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_access_pointer(nfsi->delegation) != NULL) {
		spin_lock(&clp->cl_lock);
		delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
		spin_unlock(&clp->cl_lock);
		if (delegation != NULL) {
			nfs_wb_all(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)
{
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	struct nfs_delegation *delegation;

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

	if (!clp->cl_mvops->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, clp);
		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	{
17d2c0a0 DH	27	if (delegation->cred)
17d2c0a0 DH	28	put_rpccred(delegation->cred);
1da177e4 LT	29	kfree(delegation);
	30	}
	31
8383e460 TM	32	static void nfs_free_delegation_callback(struct rcu_head *head)
	33	{
	34	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
	35
905f8d16 TM	36	nfs_do_free_delegation(delegation);
	37	}
	38
	39	static void nfs_free_delegation(struct nfs_delegation *delegation)
	40	{
905f8d16	41	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
8383e460 TM	42	}
8383e460 TM	43
b7391f44 TM	44	void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
	45	{
	46	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
	47	}
	48
bd7bf9d5	49	int nfs_have_delegation(struct inode *inode, fmode_t flags)
b7391f44 TM	50	{
	51	struct nfs_delegation *delegation;
	52	int ret = 0;
	53
	54	flags &= FMODE_READ\|FMODE_WRITE;
	55	rcu_read_lock();
	56	delegation = rcu_dereference(NFS_I(inode)->delegation);
	57	if (delegation != NULL && (delegation->type & flags) == flags) {
	58	nfs_mark_delegation_referenced(delegation);
	59	ret = 1;
	60	}
	61	rcu_read_unlock();
	62	return ret;
	63	}
	64
888e694c TM	65	static int nfs_delegation_claim_locks(struct nfs_open_context ctx, struct nfs4_state state)
	66	{
	67	struct inode *inode = state->inode;
	68	struct file_lock *fl;
d5122201	69	int status = 0;
888e694c	70
3f09df70 TM	71	if (inode->i_flock == NULL)
	72	goto out;
	73
b89f4321 AB	74	/* Protect inode->i_flock using the file locks lock */
b89f4321 AB	75	lock_flocks();
90dc7d27	76	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
888e694c TM	77	if (!(fl->fl_flags & (FL_POSIX\|FL_FLOCK)))
888e694c TM	78	continue;
cd3758e3	79	if (nfs_file_open_context(fl->fl_file) != ctx)
888e694c	80	continue;
b89f4321	81	unlock_flocks();
888e694c	82	status = nfs4_lock_delegation_recall(state, fl);
d5122201	83	if (status < 0)
3f09df70	84	goto out;
b89f4321	85	lock_flocks();
888e694c	86	}
b89f4321	87	unlock_flocks();
3f09df70	88	out:
888e694c TM	89	return status;
	90	}
	91
d18cc1fd	92	static int nfs_delegation_claim_opens(struct inode inode, const nfs4_stateid stateid)
1da177e4 LT	93	{
	94	struct nfs_inode *nfsi = NFS_I(inode);
	95	struct nfs_open_context *ctx;
	96	struct nfs4_state *state;
888e694c	97	int err;
1da177e4 LT	98
	99	again:
	100	spin_lock(&inode->i_lock);
	101	list_for_each_entry(ctx, &nfsi->open_files, list) {
	102	state = ctx->state;
	103	if (state == NULL)
	104	continue;
	105	if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
	106	continue;
90163027 TM	107	if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
90163027 TM	108	continue;
1da177e4 LT	109	get_nfs_open_context(ctx);
1da177e4 LT	110	spin_unlock(&inode->i_lock);
13437e12	111	err = nfs4_open_delegation_recall(ctx, state, stateid);
888e694c TM	112	if (err >= 0)
888e694c TM	113	err = nfs_delegation_claim_locks(ctx, state);
1da177e4	114	put_nfs_open_context(ctx);
888e694c	115	if (err != 0)
d18cc1fd	116	return err;
1da177e4 LT	117	goto again;
	118	}
	119	spin_unlock(&inode->i_lock);
d18cc1fd	120	return 0;
1da177e4 LT	121	}
	122
	123	/*
	124	* Set up a delegation on an inode
	125	*/
	126	void nfs_inode_reclaim_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	127	{
8f649c37 TM	128	struct nfs_delegation *delegation;
8f649c37 TM	129	struct rpc_cred *oldcred = NULL;
1da177e4	130
8f649c37 TM	131	rcu_read_lock();
	132	delegation = rcu_dereference(NFS_I(inode)->delegation);
	133	if (delegation != NULL) {
	134	spin_lock(&delegation->lock);
	135	if (delegation->inode != NULL) {
	136	memcpy(delegation->stateid.data, res->delegation.data,
	137	sizeof(delegation->stateid.data));
	138	delegation->type = res->delegation_type;
	139	delegation->maxsize = res->maxsize;
	140	oldcred = delegation->cred;
	141	delegation->cred = get_rpccred(cred);
	142	clear_bit(NFS_DELEGATION_NEED_RECLAIM,
	143	&delegation->flags);
	144	NFS_I(inode)->delegation_state = delegation->type;
	145	spin_unlock(&delegation->lock);
	146	put_rpccred(oldcred);
	147	rcu_read_unlock();
	148	} else {
	149	/* We appear to have raced with a delegation return. */
	150	spin_unlock(&delegation->lock);
	151	rcu_read_unlock();
	152	nfs_inode_set_delegation(inode, cred, res);
	153	}
	154	} else {
	155	rcu_read_unlock();
	156	}
1da177e4 LT	157	}
1da177e4 LT	158
57bfa891 TM	159	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
	160	{
	161	int res = 0;
	162
	163	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	164	nfs_free_delegation(delegation);
	165	return res;
	166	}
	167
86e89489 TM	168	static struct inode nfs_delegation_grab_inode(struct nfs_delegation delegation)
	169	{
	170	struct inode *inode = NULL;
	171
	172	spin_lock(&delegation->lock);
	173	if (delegation->inode != NULL)
	174	inode = igrab(delegation->inode);
	175	spin_unlock(&delegation->lock);
	176	return inode;
	177	}
	178
17d2c0a0 DH	179	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi,
	180	const nfs4_stateid *stateid,
	181	struct nfs_client *clp)
57bfa891	182	{
17d2c0a0 DH	183	struct nfs_delegation *delegation =
	184	rcu_dereference_protected(nfsi->delegation,
	185	lockdep_is_held(&clp->cl_lock));
57bfa891 TM	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	211	struct nfs_inode *nfsi = NFS_I(inode);
17d2c0a0	212	struct nfs_delegation delegation, old_delegation;
57bfa891	213	struct nfs_delegation *freeme = NULL;
1da177e4 LT	214	int status = 0;
1da177e4 LT	215
8535b2be	216	delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
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);
17d2c0a0 DH	230	old_delegation = rcu_dereference_protected(nfsi->delegation,
	231	lockdep_is_held(&clp->cl_lock));
	232	if (old_delegation != NULL) {
	233	if (memcmp(&delegation->stateid, &old_delegation->stateid,
	234	sizeof(old_delegation->stateid)) == 0 &&
	235	delegation->type == old_delegation->type) {
57bfa891	236	goto out;
1da177e4	237	}
57bfa891 TM	238	/*
	239	* Deal with broken servers that hand out two
	240	* delegations for the same file.
	241	*/
	242	dfprintk(FILE, "%s: server %s handed out "
	243	"a duplicate delegation!\n",
3110ff80	244	__func__, clp->cl_hostname);
17d2c0a0	245	if (delegation->type <= old_delegation->type) {
57bfa891 TM	246	freeme = delegation;
	247	delegation = NULL;
	248	goto out;
	249	}
17d2c0a0	250	freeme = nfs_detach_delegation_locked(nfsi, NULL, clp);
1da177e4	251	}
57bfa891 TM	252	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	253	nfsi->delegation_state = delegation->type;
	254	rcu_assign_pointer(nfsi->delegation, delegation);
	255	delegation = NULL;
412c77ce TM	256
	257	/* Ensure we revalidate the attributes and page cache! */
	258	spin_lock(&inode->i_lock);
	259	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	260	spin_unlock(&inode->i_lock);
	261
57bfa891	262	out:
1da177e4	263	spin_unlock(&clp->cl_lock);
603c83da TM	264	if (delegation != NULL)
603c83da TM	265	nfs_free_delegation(delegation);
57bfa891 TM	266	if (freeme != NULL)
57bfa891 TM	267	nfs_do_return_delegation(inode, freeme, 0);
1da177e4 LT	268	return status;
	269	}
	270
1da177e4 LT	271	/*
	272	* Basic procedure for returning a delegation to the server
	273	*/
d18cc1fd	274	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
1da177e4	275	{
1da177e4	276	struct nfs_inode *nfsi = NFS_I(inode);
d18cc1fd	277	int err;
1da177e4	278
3f09df70 TM	279	/*
	280	* Guard against new delegated open/lock/unlock calls and against
	281	* state recovery
	282	*/
1da177e4	283	down_write(&nfsi->rwsem);
d18cc1fd	284	err = nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4	285	up_write(&nfsi->rwsem);
d18cc1fd TM	286	if (err)
d18cc1fd TM	287	goto out;
1da177e4	288
d18cc1fd TM	289	err = nfs_do_return_delegation(inode, delegation, issync);
	290	out:
	291	return err;
90163027 TM	292	}
90163027 TM	293
515d8611 TM	294	/*
	295	* Return all delegations that have been marked for return
	296	*/
d18cc1fd	297	int nfs_client_return_marked_delegations(struct nfs_client *clp)
515d8611 TM	298	{
	299	struct nfs_delegation *delegation;
	300	struct inode *inode;
d18cc1fd	301	int err = 0;
515d8611 TM	302
	303	restart:
	304	rcu_read_lock();
	305	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	306	if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
	307	continue;
	308	inode = nfs_delegation_grab_inode(delegation);
	309	if (inode == NULL)
	310	continue;
	311	spin_lock(&clp->cl_lock);
17d2c0a0	312	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
515d8611 TM	313	spin_unlock(&clp->cl_lock);
515d8611 TM	314	rcu_read_unlock();
d18cc1fd TM	315	if (delegation != NULL) {
	316	filemap_flush(inode->i_mapping);
	317	err = __nfs_inode_return_delegation(inode, delegation, 0);
	318	}
515d8611	319	iput(inode);
d18cc1fd TM	320	if (!err)
	321	goto restart;
	322	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	323	return err;
515d8611 TM	324	}
515d8611 TM	325	rcu_read_unlock();
d18cc1fd	326	return 0;
515d8611 TM	327	}
515d8611 TM	328
e6f81075 TM	329	/*
	330	* This function returns the delegation without reclaiming opens
	331	* or protecting against delegation reclaims.
	332	* It is therefore really only safe to be called from
	333	* nfs4_clear_inode()
	334	*/
	335	void nfs_inode_return_delegation_noreclaim(struct inode *inode)
	336	{
	337	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	338	struct nfs_inode *nfsi = NFS_I(inode);
	339	struct nfs_delegation *delegation;
	340
17d2c0a0	341	if (rcu_access_pointer(nfsi->delegation) != NULL) {
e6f81075	342	spin_lock(&clp->cl_lock);
17d2c0a0	343	delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
e6f81075 TM	344	spin_unlock(&clp->cl_lock);
	345	if (delegation != NULL)
	346	nfs_do_return_delegation(inode, delegation, 0);
	347	}
	348	}
	349
90163027 TM	350	int nfs_inode_return_delegation(struct inode *inode)
	351	{
	352	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	353	struct nfs_inode *nfsi = NFS_I(inode);
	354	struct nfs_delegation *delegation;
	355	int err = 0;
	356
17d2c0a0	357	if (rcu_access_pointer(nfsi->delegation) != NULL) {
90163027	358	spin_lock(&clp->cl_lock);
17d2c0a0	359	delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
90163027	360	spin_unlock(&clp->cl_lock);
d18cc1fd	361	if (delegation != NULL) {
1b924e5f	362	nfs_wb_all(inode);
d18cc1fd TM	363	err = __nfs_inode_return_delegation(inode, delegation, 1);
d18cc1fd TM	364	}
90163027 TM	365	}
90163027 TM	366	return err;
1da177e4 LT	367	}
1da177e4 LT	368
6411bd4a TM	369	static void nfs_mark_return_delegation(struct nfs_client clp, struct nfs_delegation delegation)
	370	{
	371	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
	372	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	373	}
	374
1da177e4 LT	375	/*
	376	* Return all delegations associated to a super block
	377	*/
515d8611	378	void nfs_super_return_all_delegations(struct super_block *sb)
1da177e4	379	{
7539bbab	380	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4	381	struct nfs_delegation *delegation;
1da177e4 LT	382
	383	if (clp == NULL)
	384	return;
8383e460 TM	385	rcu_read_lock();
8383e460 TM	386	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	387	spin_lock(&delegation->lock);
86e89489 TM	388	if (delegation->inode != NULL && delegation->inode->i_sb == sb)
515d8611	389	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
86e89489	390	spin_unlock(&delegation->lock);
1da177e4	391	}
8383e460	392	rcu_read_unlock();
d18cc1fd TM	393	if (nfs_client_return_marked_delegations(clp) != 0)
d18cc1fd TM	394	nfs4_schedule_state_manager(clp);
515d8611 TM	395	}
515d8611 TM	396
c79571a5 AB	397	static
c79571a5 AB	398	void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
515d8611 TM	399	{
	400	struct nfs_delegation *delegation;
	401
	402	rcu_read_lock();
707fb4b3	403	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
c79571a5 AB	404	if ((delegation->type == (FMODE_READ\|FMODE_WRITE)) && !(flags & FMODE_WRITE))
	405	continue;
	406	if (delegation->type & flags)
	407	nfs_mark_return_delegation(clp, delegation);
707fb4b3	408	}
515d8611	409	rcu_read_unlock();
1da177e4 LT	410	}
1da177e4 LT	411
c79571a5 AB	412	static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
	413	{
	414	nfs_client_mark_return_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	415	}
	416
b0d3ded1	417	static void nfs_delegation_run_state_manager(struct nfs_client *clp)
58d9714a	418	{
b0d3ded1 TM	419	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
b0d3ded1 TM	420	nfs4_schedule_state_manager(clp);
58d9714a TM	421	}
58d9714a TM	422
31f09607	423	void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
58d9714a	424	{
c79571a5	425	nfs_client_mark_return_all_delegation_types(clp, flags);
b0d3ded1	426	nfs_delegation_run_state_manager(clp);
58d9714a TM	427	}
58d9714a TM	428
c79571a5 AB	429	void nfs_expire_all_delegations(struct nfs_client *clp)
	430	{
	431	nfs_expire_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	432	}
	433
1da177e4 LT	434	/*
	435	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	436	*/
adfa6f98	437	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4	438	{
1da177e4 LT	439	if (clp == NULL)
1da177e4 LT	440	return;
707fb4b3	441	nfs_client_mark_return_all_delegations(clp);
1da177e4 LT	442	}
1da177e4 LT	443
b7391f44 TM	444	static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
	445	{
	446	struct nfs_delegation *delegation;
	447
	448	rcu_read_lock();
	449	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	450	if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
	451	continue;
b4a6f496	452	nfs_mark_return_delegation(clp, delegation);
b7391f44 TM	453	}
	454	rcu_read_unlock();
	455	}
	456
	457	void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
	458	{
	459	nfs_client_mark_return_unreferenced_delegations(clp);
	460	nfs_delegation_run_state_manager(clp);
	461	}
	462
1da177e4 LT	463	/*
	464	* Asynchronous delegation recall!
	465	*/
e047a10c	466	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
1da177e4	467	{
6411bd4a TM	468	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
6411bd4a TM	469	struct nfs_delegation *delegation;
1da177e4	470
6411bd4a TM	471	rcu_read_lock();
6411bd4a TM	472	delegation = rcu_dereference(NFS_I(inode)->delegation);
2597641d	473
e047a10c	474	if (!clp->cl_mvops->validate_stateid(delegation, stateid)) {
6411bd4a TM	475	rcu_read_unlock();
	476	return -ENOENT;
	477	}
2597641d	478
6411bd4a TM	479	nfs_mark_return_delegation(clp, delegation);
	480	rcu_read_unlock();
	481	nfs_delegation_run_state_manager(clp);
	482	return 0;
1da177e4 LT	483	}
	484
	485	/*
	486	* Retrieve the inode associated with a delegation
	487	*/
adfa6f98	488	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	489	{
	490	struct nfs_delegation *delegation;
	491	struct inode *res = NULL;
8383e460 TM	492	rcu_read_lock();
8383e460 TM	493	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	494	spin_lock(&delegation->lock);
	495	if (delegation->inode != NULL &&
	496	nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1da177e4	497	res = igrab(delegation->inode);
1da177e4	498	}
86e89489 TM	499	spin_unlock(&delegation->lock);
	500	if (res != NULL)
	501	break;
1da177e4	502	}
8383e460	503	rcu_read_unlock();
1da177e4 LT	504	return res;
	505	}
	506
	507	/*
	508	* Mark all delegations as needing to be reclaimed
	509	*/
adfa6f98	510	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	511	{
1da177e4 LT	512	struct nfs_delegation *delegation;
8383e460 TM	513	rcu_read_lock();
8383e460 TM	514	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
15c831bf	515	set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
8383e460	516	rcu_read_unlock();
1da177e4 LT	517	}
	518
	519	/*
	520	* Reap all unclaimed delegations after reboot recovery is done
	521	*/
adfa6f98	522	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	523	{
8383e460	524	struct nfs_delegation *delegation;
86e89489	525	struct inode *inode;
8383e460 TM	526	restart:
	527	rcu_read_lock();
	528	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
15c831bf	529	if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
1da177e4	530	continue;
86e89489 TM	531	inode = nfs_delegation_grab_inode(delegation);
	532	if (inode == NULL)
	533	continue;
8383e460	534	spin_lock(&clp->cl_lock);
17d2c0a0	535	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
8383e460 TM	536	spin_unlock(&clp->cl_lock);
	537	rcu_read_unlock();
	538	if (delegation != NULL)
905f8d16	539	nfs_free_delegation(delegation);
86e89489	540	iput(inode);
8383e460	541	goto restart;
1da177e4	542	}
8383e460	543	rcu_read_unlock();
1da177e4	544	}
3e4f6290 TM	545
	546	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	547	{
3e4f6290 TM	548	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	549	struct nfs_delegation *delegation;
8383e460	550	int ret = 0;
3e4f6290	551
8383e460 TM	552	rcu_read_lock();
8383e460 TM	553	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	554	if (delegation != NULL) {
3e4f6290 TM	555	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	556	ret = 1;
3e4f6290	557	}
8383e460 TM	558	rcu_read_unlock();
8383e460 TM	559	return ret;
3e4f6290	560	}