[mirror_ubuntu-zesty-kernel.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/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 void 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;
		goto again;
	}
	spin_unlock(&inode->i_lock);
}

/*
 * Set up a delegation on an inode
 */
void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
{
	struct nfs_delegation *delegation = NFS_I(inode)->delegation;
	struct rpc_cred *oldcred;

	if (delegation == NULL)
		return;
	memcpy(delegation->stateid.data, res->delegation.data,
			sizeof(delegation->stateid.data));
	delegation->type = res->delegation_type;
	delegation->maxsize = res->maxsize;
	oldcred = delegation->cred;
	delegation->cred = get_rpccred(cred);
	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
	NFS_I(inode)->delegation_state = delegation->type;
	smp_wmb();
	put_rpccred(oldcred);
}

static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
{
	int res = 0;

	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	nfs_free_delegation(delegation);
	return res;
}

static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
{
	struct inode *inode = NULL;

	spin_lock(&delegation->lock);
	if (delegation->inode != NULL)
		inode = igrab(delegation->inode);
	spin_unlock(&delegation->lock);
	return inode;
}

static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
{
	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);

	if (delegation == NULL)
		goto nomatch;
	spin_lock(&delegation->lock);
	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
				sizeof(delegation->stateid.data)) != 0)
		goto nomatch_unlock;
	list_del_rcu(&delegation->super_list);
	delegation->inode = NULL;
	nfsi->delegation_state = 0;
	rcu_assign_pointer(nfsi->delegation, NULL);
	spin_unlock(&delegation->lock);
	return delegation;
nomatch_unlock:
	spin_unlock(&delegation->lock);
nomatch:
	return NULL;
}

/*
 * Set up a delegation on an inode
 */
int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
{
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_delegation *delegation;
	struct nfs_delegation *freeme = NULL;
	int status = 0;

	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
	if (delegation == NULL)
		return -ENOMEM;
	memcpy(delegation->stateid.data, res->delegation.data,
			sizeof(delegation->stateid.data));
	delegation->type = res->delegation_type;
	delegation->maxsize = res->maxsize;
	delegation->change_attr = nfsi->change_attr;
	delegation->cred = get_rpccred(cred);
	delegation->inode = inode;
	delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
	spin_lock_init(&delegation->lock);

	spin_lock(&clp->cl_lock);
	if (rcu_dereference(nfsi->delegation) != NULL) {
		if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
					sizeof(delegation->stateid)) == 0 &&
				delegation->type == nfsi->delegation->type) {
			goto out;
		}
		/*
		 * Deal with broken servers that hand out two
		 * delegations for the same file.
		 */
		dfprintk(FILE, "%s: server %s handed out "
				"a duplicate delegation!\n",
				__func__, clp->cl_hostname);
		if (delegation->type <= nfsi->delegation->type) {
			freeme = delegation;
			delegation = NULL;
			goto out;
		}
		freeme = nfs_detach_delegation_locked(nfsi, NULL);
	}
	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	nfsi->delegation_state = delegation->type;
	rcu_assign_pointer(nfsi->delegation, delegation);
	delegation = NULL;

	/* Ensure we revalidate the attributes and page cache! */
	spin_lock(&inode->i_lock);
	nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
	spin_unlock(&inode->i_lock);

out:
	spin_unlock(&clp->cl_lock);
	if (delegation != NULL)
		nfs_free_delegation(delegation);
	if (freeme != NULL)
		nfs_do_return_delegation(inode, freeme, 0);
	return status;
}

/* Sync all data to disk upon delegation return */
static void nfs_msync_inode(struct inode *inode)
{
	filemap_fdatawrite(inode->i_mapping);
	nfs_wb_all(inode);
	filemap_fdatawait(inode->i_mapping);
}

/*
 * Basic procedure for returning a delegation to the server
 */
static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
{
	struct nfs_inode *nfsi = NFS_I(inode);

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

	return nfs_do_return_delegation(inode, delegation, 1);
}

/*
 * Return all delegations that have been marked for return
 */
void nfs_client_return_marked_delegations(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_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)
			__nfs_inode_return_delegation(inode, delegation);
		iput(inode);
		goto restart;
	}
	rcu_read_unlock();
}

/*
 * 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)
			err = __nfs_inode_return_delegation(inode, delegation);
	}
	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();
	nfs_client_return_marked_delegations(clp);
}

static void nfs_client_mark_return_all_delegations(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_RETURN, &delegation->flags);
		set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	}
	rcu_read_unlock();
}

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_delegations(struct nfs_client *clp)
{
	nfs_client_mark_return_all_delegations(clp);
	nfs_delegation_run_state_manager(clp);
}

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