[deliverable/linux.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/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>
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	{
17d2c0a0 DH	26	if (delegation->cred)
17d2c0a0 DH	27	put_rpccred(delegation->cred);
1da177e4 LT	28	kfree(delegation);
	29	}
	30
8383e460 TM	31	static void nfs_free_delegation_callback(struct rcu_head *head)
	32	{
	33	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
	34
905f8d16 TM	35	nfs_do_free_delegation(delegation);
	36	}
	37
	38	static void nfs_free_delegation(struct nfs_delegation *delegation)
	39	{
905f8d16	40	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
8383e460 TM	41	}
8383e460 TM	42
b7391f44 TM	43	void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
	44	{
	45	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
	46	}
	47
bd7bf9d5	48	int nfs_have_delegation(struct inode *inode, fmode_t flags)
b7391f44 TM	49	{
	50	struct nfs_delegation *delegation;
	51	int ret = 0;
	52
	53	flags &= FMODE_READ\|FMODE_WRITE;
	54	rcu_read_lock();
	55	delegation = rcu_dereference(NFS_I(inode)->delegation);
	56	if (delegation != NULL && (delegation->type & flags) == flags) {
	57	nfs_mark_delegation_referenced(delegation);
	58	ret = 1;
	59	}
	60	rcu_read_unlock();
	61	return ret;
	62	}
	63
888e694c TM	64	static int nfs_delegation_claim_locks(struct nfs_open_context ctx, struct nfs4_state state)
	65	{
	66	struct inode *inode = state->inode;
	67	struct file_lock *fl;
d5122201	68	int status = 0;
888e694c	69
3f09df70 TM	70	if (inode->i_flock == NULL)
	71	goto out;
	72
b89f4321 AB	73	/* Protect inode->i_flock using the file locks lock */
b89f4321 AB	74	lock_flocks();
90dc7d27	75	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
888e694c TM	76	if (!(fl->fl_flags & (FL_POSIX\|FL_FLOCK)))
888e694c TM	77	continue;
cd3758e3	78	if (nfs_file_open_context(fl->fl_file) != ctx)
888e694c	79	continue;
b89f4321	80	unlock_flocks();
888e694c	81	status = nfs4_lock_delegation_recall(state, fl);
d5122201	82	if (status < 0)
3f09df70	83	goto out;
b89f4321	84	lock_flocks();
888e694c	85	}
b89f4321	86	unlock_flocks();
3f09df70	87	out:
888e694c TM	88	return status;
	89	}
	90
d18cc1fd	91	static int nfs_delegation_claim_opens(struct inode inode, const nfs4_stateid stateid)
1da177e4 LT	92	{
	93	struct nfs_inode *nfsi = NFS_I(inode);
	94	struct nfs_open_context *ctx;
	95	struct nfs4_state *state;
888e694c	96	int err;
1da177e4 LT	97
	98	again:
	99	spin_lock(&inode->i_lock);
	100	list_for_each_entry(ctx, &nfsi->open_files, list) {
	101	state = ctx->state;
	102	if (state == NULL)
	103	continue;
	104	if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
	105	continue;
90163027 TM	106	if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
90163027 TM	107	continue;
1da177e4 LT	108	get_nfs_open_context(ctx);
1da177e4 LT	109	spin_unlock(&inode->i_lock);
13437e12	110	err = nfs4_open_delegation_recall(ctx, state, stateid);
888e694c TM	111	if (err >= 0)
888e694c TM	112	err = nfs_delegation_claim_locks(ctx, state);
1da177e4	113	put_nfs_open_context(ctx);
888e694c	114	if (err != 0)
d18cc1fd	115	return err;
1da177e4 LT	116	goto again;
	117	}
	118	spin_unlock(&inode->i_lock);
d18cc1fd	119	return 0;
1da177e4 LT	120	}
	121
	122	/*
	123	* Set up a delegation on an inode
	124	*/
	125	void nfs_inode_reclaim_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	126	{
8f649c37 TM	127	struct nfs_delegation *delegation;
8f649c37 TM	128	struct rpc_cred *oldcred = NULL;
1da177e4	129
8f649c37 TM	130	rcu_read_lock();
	131	delegation = rcu_dereference(NFS_I(inode)->delegation);
	132	if (delegation != NULL) {
	133	spin_lock(&delegation->lock);
	134	if (delegation->inode != NULL) {
	135	memcpy(delegation->stateid.data, res->delegation.data,
	136	sizeof(delegation->stateid.data));
	137	delegation->type = res->delegation_type;
	138	delegation->maxsize = res->maxsize;
	139	oldcred = delegation->cred;
	140	delegation->cred = get_rpccred(cred);
	141	clear_bit(NFS_DELEGATION_NEED_RECLAIM,
	142	&delegation->flags);
	143	NFS_I(inode)->delegation_state = delegation->type;
	144	spin_unlock(&delegation->lock);
	145	put_rpccred(oldcred);
	146	rcu_read_unlock();
	147	} else {
	148	/* We appear to have raced with a delegation return. */
	149	spin_unlock(&delegation->lock);
	150	rcu_read_unlock();
	151	nfs_inode_set_delegation(inode, cred, res);
	152	}
	153	} else {
	154	rcu_read_unlock();
	155	}
1da177e4 LT	156	}
1da177e4 LT	157
57bfa891 TM	158	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
	159	{
	160	int res = 0;
	161
	162	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	163	nfs_free_delegation(delegation);
	164	return res;
	165	}
	166
86e89489 TM	167	static struct inode nfs_delegation_grab_inode(struct nfs_delegation delegation)
	168	{
	169	struct inode *inode = NULL;
	170
	171	spin_lock(&delegation->lock);
	172	if (delegation->inode != NULL)
	173	inode = igrab(delegation->inode);
	174	spin_unlock(&delegation->lock);
	175	return inode;
	176	}
	177
17d2c0a0 DH	178	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi,
	179	const nfs4_stateid *stateid,
	180	struct nfs_client *clp)
57bfa891	181	{
17d2c0a0 DH	182	struct nfs_delegation *delegation =
	183	rcu_dereference_protected(nfsi->delegation,
	184	lockdep_is_held(&clp->cl_lock));
57bfa891 TM	185
	186	if (delegation == NULL)
	187	goto nomatch;
34310430	188	spin_lock(&delegation->lock);
57bfa891 TM	189	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
57bfa891 TM	190	sizeof(delegation->stateid.data)) != 0)
34310430	191	goto nomatch_unlock;
57bfa891	192	list_del_rcu(&delegation->super_list);
86e89489	193	delegation->inode = NULL;
57bfa891 TM	194	nfsi->delegation_state = 0;
57bfa891 TM	195	rcu_assign_pointer(nfsi->delegation, NULL);
34310430	196	spin_unlock(&delegation->lock);
57bfa891	197	return delegation;
34310430 TM	198	nomatch_unlock:
34310430 TM	199	spin_unlock(&delegation->lock);
57bfa891 TM	200	nomatch:
	201	return NULL;
	202	}
	203
1da177e4 LT	204	/*
	205	* Set up a delegation on an inode
	206	*/
	207	int nfs_inode_set_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	208	{
7539bbab	209	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4	210	struct nfs_inode *nfsi = NFS_I(inode);
17d2c0a0	211	struct nfs_delegation delegation, old_delegation;
57bfa891	212	struct nfs_delegation *freeme = NULL;
1da177e4 LT	213	int status = 0;
1da177e4 LT	214
8535b2be	215	delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
1da177e4 LT	216	if (delegation == NULL)
	217	return -ENOMEM;
	218	memcpy(delegation->stateid.data, res->delegation.data,
	219	sizeof(delegation->stateid.data));
	220	delegation->type = res->delegation_type;
	221	delegation->maxsize = res->maxsize;
beb2a5ec	222	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	223	delegation->cred = get_rpccred(cred);
1da177e4 LT	224	delegation->inode = inode;
b7391f44	225	delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
34310430	226	spin_lock_init(&delegation->lock);
1da177e4 LT	227
1da177e4 LT	228	spin_lock(&clp->cl_lock);
17d2c0a0 DH	229	old_delegation = rcu_dereference_protected(nfsi->delegation,
	230	lockdep_is_held(&clp->cl_lock));
	231	if (old_delegation != NULL) {
	232	if (memcmp(&delegation->stateid, &old_delegation->stateid,
	233	sizeof(old_delegation->stateid)) == 0 &&
	234	delegation->type == old_delegation->type) {
57bfa891	235	goto out;
1da177e4	236	}
57bfa891 TM	237	/*
	238	* Deal with broken servers that hand out two
	239	* delegations for the same file.
	240	*/
	241	dfprintk(FILE, "%s: server %s handed out "
	242	"a duplicate delegation!\n",
3110ff80	243	__func__, clp->cl_hostname);
17d2c0a0	244	if (delegation->type <= old_delegation->type) {
57bfa891 TM	245	freeme = delegation;
	246	delegation = NULL;
	247	goto out;
	248	}
17d2c0a0	249	freeme = nfs_detach_delegation_locked(nfsi, NULL, clp);
1da177e4	250	}
57bfa891 TM	251	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	252	nfsi->delegation_state = delegation->type;
	253	rcu_assign_pointer(nfsi->delegation, delegation);
	254	delegation = NULL;
412c77ce TM	255
	256	/* Ensure we revalidate the attributes and page cache! */
	257	spin_lock(&inode->i_lock);
	258	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	259	spin_unlock(&inode->i_lock);
	260
57bfa891	261	out:
1da177e4	262	spin_unlock(&clp->cl_lock);
603c83da TM	263	if (delegation != NULL)
603c83da TM	264	nfs_free_delegation(delegation);
57bfa891 TM	265	if (freeme != NULL)
57bfa891 TM	266	nfs_do_return_delegation(inode, freeme, 0);
1da177e4 LT	267	return status;
	268	}
	269
1da177e4 LT	270	/*
	271	* Basic procedure for returning a delegation to the server
	272	*/
d18cc1fd	273	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
1da177e4	274	{
1da177e4	275	struct nfs_inode *nfsi = NFS_I(inode);
d18cc1fd	276	int err;
1da177e4	277
3f09df70 TM	278	/*
	279	* Guard against new delegated open/lock/unlock calls and against
	280	* state recovery
	281	*/
1da177e4	282	down_write(&nfsi->rwsem);
d18cc1fd	283	err = nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4	284	up_write(&nfsi->rwsem);
d18cc1fd TM	285	if (err)
d18cc1fd TM	286	goto out;
1da177e4	287
d18cc1fd TM	288	err = nfs_do_return_delegation(inode, delegation, issync);
	289	out:
	290	return err;
90163027 TM	291	}
90163027 TM	292
515d8611 TM	293	/*
	294	* Return all delegations that have been marked for return
	295	*/
d18cc1fd	296	int nfs_client_return_marked_delegations(struct nfs_client *clp)
515d8611 TM	297	{
	298	struct nfs_delegation *delegation;
	299	struct inode *inode;
d18cc1fd	300	int err = 0;
515d8611 TM	301
	302	restart:
	303	rcu_read_lock();
	304	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	305	if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
	306	continue;
	307	inode = nfs_delegation_grab_inode(delegation);
	308	if (inode == NULL)
	309	continue;
	310	spin_lock(&clp->cl_lock);
17d2c0a0	311	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
515d8611 TM	312	spin_unlock(&clp->cl_lock);
515d8611 TM	313	rcu_read_unlock();
d18cc1fd TM	314	if (delegation != NULL) {
	315	filemap_flush(inode->i_mapping);
	316	err = __nfs_inode_return_delegation(inode, delegation, 0);
	317	}
515d8611	318	iput(inode);
d18cc1fd TM	319	if (!err)
	320	goto restart;
	321	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	322	return err;
515d8611 TM	323	}
515d8611 TM	324	rcu_read_unlock();
d18cc1fd	325	return 0;
515d8611 TM	326	}
515d8611 TM	327
e6f81075 TM	328	/*
	329	* This function returns the delegation without reclaiming opens
	330	* or protecting against delegation reclaims.
	331	* It is therefore really only safe to be called from
	332	* nfs4_clear_inode()
	333	*/
	334	void nfs_inode_return_delegation_noreclaim(struct inode *inode)
	335	{
	336	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	337	struct nfs_inode *nfsi = NFS_I(inode);
	338	struct nfs_delegation *delegation;
	339
17d2c0a0	340	if (rcu_access_pointer(nfsi->delegation) != NULL) {
e6f81075	341	spin_lock(&clp->cl_lock);
17d2c0a0	342	delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
e6f81075 TM	343	spin_unlock(&clp->cl_lock);
	344	if (delegation != NULL)
	345	nfs_do_return_delegation(inode, delegation, 0);
	346	}
	347	}
	348
90163027 TM	349	int nfs_inode_return_delegation(struct inode *inode)
	350	{
	351	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	352	struct nfs_inode *nfsi = NFS_I(inode);
	353	struct nfs_delegation *delegation;
	354	int err = 0;
	355
17d2c0a0	356	if (rcu_access_pointer(nfsi->delegation) != NULL) {
90163027	357	spin_lock(&clp->cl_lock);
17d2c0a0	358	delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
90163027	359	spin_unlock(&clp->cl_lock);
d18cc1fd	360	if (delegation != NULL) {
1b924e5f	361	nfs_wb_all(inode);
d18cc1fd TM	362	err = __nfs_inode_return_delegation(inode, delegation, 1);
d18cc1fd TM	363	}
90163027 TM	364	}
90163027 TM	365	return err;
1da177e4 LT	366	}
1da177e4 LT	367
6411bd4a TM	368	static void nfs_mark_return_delegation(struct nfs_client clp, struct nfs_delegation delegation)
	369	{
	370	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
	371	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	372	}
	373
1da177e4 LT	374	/*
	375	* Return all delegations associated to a super block
	376	*/
515d8611	377	void nfs_super_return_all_delegations(struct super_block *sb)
1da177e4	378	{
7539bbab	379	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4	380	struct nfs_delegation *delegation;
1da177e4 LT	381
	382	if (clp == NULL)
	383	return;
8383e460 TM	384	rcu_read_lock();
8383e460 TM	385	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	386	spin_lock(&delegation->lock);
86e89489 TM	387	if (delegation->inode != NULL && delegation->inode->i_sb == sb)
515d8611	388	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
86e89489	389	spin_unlock(&delegation->lock);
1da177e4	390	}
8383e460	391	rcu_read_unlock();
d18cc1fd TM	392	if (nfs_client_return_marked_delegations(clp) != 0)
d18cc1fd TM	393	nfs4_schedule_state_manager(clp);
515d8611 TM	394	}
515d8611 TM	395
c79571a5 AB	396	static
c79571a5 AB	397	void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
515d8611 TM	398	{
	399	struct nfs_delegation *delegation;
	400
	401	rcu_read_lock();
707fb4b3	402	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
c79571a5 AB	403	if ((delegation->type == (FMODE_READ\|FMODE_WRITE)) && !(flags & FMODE_WRITE))
	404	continue;
	405	if (delegation->type & flags)
	406	nfs_mark_return_delegation(clp, delegation);
707fb4b3	407	}
515d8611	408	rcu_read_unlock();
1da177e4 LT	409	}
1da177e4 LT	410
c79571a5 AB	411	static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
	412	{
	413	nfs_client_mark_return_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	414	}
	415
b0d3ded1	416	static void nfs_delegation_run_state_manager(struct nfs_client *clp)
58d9714a	417	{
b0d3ded1 TM	418	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
b0d3ded1 TM	419	nfs4_schedule_state_manager(clp);
58d9714a TM	420	}
58d9714a TM	421
31f09607	422	void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
58d9714a	423	{
c79571a5	424	nfs_client_mark_return_all_delegation_types(clp, flags);
b0d3ded1	425	nfs_delegation_run_state_manager(clp);
58d9714a TM	426	}
58d9714a TM	427
c79571a5 AB	428	void nfs_expire_all_delegations(struct nfs_client *clp)
	429	{
	430	nfs_expire_all_delegation_types(clp, FMODE_READ\|FMODE_WRITE);
	431	}
	432
1da177e4 LT	433	/*
	434	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	435	*/
adfa6f98	436	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4	437	{
1da177e4 LT	438	if (clp == NULL)
1da177e4 LT	439	return;
707fb4b3	440	nfs_client_mark_return_all_delegations(clp);
1da177e4 LT	441	}
1da177e4 LT	442
b7391f44 TM	443	static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
	444	{
	445	struct nfs_delegation *delegation;
	446
	447	rcu_read_lock();
	448	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	449	if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
	450	continue;
b4a6f496	451	nfs_mark_return_delegation(clp, delegation);
b7391f44 TM	452	}
	453	rcu_read_unlock();
	454	}
	455
	456	void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
	457	{
	458	nfs_client_mark_return_unreferenced_delegations(clp);
	459	nfs_delegation_run_state_manager(clp);
	460	}
	461
1da177e4 LT	462	/*
	463	* Asynchronous delegation recall!
	464	*/
e047a10c	465	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
1da177e4	466	{
6411bd4a TM	467	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
6411bd4a TM	468	struct nfs_delegation *delegation;
1da177e4	469
6411bd4a TM	470	rcu_read_lock();
6411bd4a TM	471	delegation = rcu_dereference(NFS_I(inode)->delegation);
2597641d	472
e047a10c	473	if (!clp->cl_mvops->validate_stateid(delegation, stateid)) {
6411bd4a TM	474	rcu_read_unlock();
	475	return -ENOENT;
	476	}
2597641d	477
6411bd4a TM	478	nfs_mark_return_delegation(clp, delegation);
	479	rcu_read_unlock();
	480	nfs_delegation_run_state_manager(clp);
	481	return 0;
1da177e4 LT	482	}
	483
	484	/*
	485	* Retrieve the inode associated with a delegation
	486	*/
adfa6f98	487	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	488	{
	489	struct nfs_delegation *delegation;
	490	struct inode *res = NULL;
8383e460 TM	491	rcu_read_lock();
8383e460 TM	492	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	493	spin_lock(&delegation->lock);
	494	if (delegation->inode != NULL &&
	495	nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1da177e4	496	res = igrab(delegation->inode);
1da177e4	497	}
86e89489 TM	498	spin_unlock(&delegation->lock);
	499	if (res != NULL)
	500	break;
1da177e4	501	}
8383e460	502	rcu_read_unlock();
1da177e4 LT	503	return res;
	504	}
	505
	506	/*
	507	* Mark all delegations as needing to be reclaimed
	508	*/
adfa6f98	509	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	510	{
1da177e4 LT	511	struct nfs_delegation *delegation;
8383e460 TM	512	rcu_read_lock();
8383e460 TM	513	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
15c831bf	514	set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
8383e460	515	rcu_read_unlock();
1da177e4 LT	516	}
	517
	518	/*
	519	* Reap all unclaimed delegations after reboot recovery is done
	520	*/
adfa6f98	521	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	522	{
8383e460	523	struct nfs_delegation *delegation;
86e89489	524	struct inode *inode;
8383e460 TM	525	restart:
	526	rcu_read_lock();
	527	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
15c831bf	528	if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
1da177e4	529	continue;
86e89489 TM	530	inode = nfs_delegation_grab_inode(delegation);
	531	if (inode == NULL)
	532	continue;
8383e460	533	spin_lock(&clp->cl_lock);
17d2c0a0	534	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
8383e460 TM	535	spin_unlock(&clp->cl_lock);
	536	rcu_read_unlock();
	537	if (delegation != NULL)
905f8d16	538	nfs_free_delegation(delegation);
86e89489	539	iput(inode);
8383e460	540	goto restart;
1da177e4	541	}
8383e460	542	rcu_read_unlock();
1da177e4	543	}
3e4f6290 TM	544
	545	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	546	{
3e4f6290 TM	547	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	548	struct nfs_delegation *delegation;
8383e460	549	int ret = 0;
3e4f6290	550
8383e460 TM	551	rcu_read_lock();
8383e460 TM	552	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	553	if (delegation != NULL) {
3e4f6290 TM	554	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	555	ret = 1;
3e4f6290	556	}
8383e460 TM	557	rcu_read_unlock();
8383e460 TM	558	return ret;
3e4f6290	559	}