[linux-block.git] / fs / nfs / delegation.c

/*
 * linux/fs/nfs/delegation.c
 *
 * Copyright (C) 2004 Trond Myklebust
 *
 * NFS file delegation management
 *
 */
#include <linux/completion.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>

#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_xdr.h>

#include "nfs4_fs.h"
#include "delegation.h"
#include "internal.h"

static void nfs_do_free_delegation(struct nfs_delegation *delegation)
{
	kfree(delegation);
}

static void nfs_free_delegation_callback(struct rcu_head *head)
{
	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);

	nfs_do_free_delegation(delegation);
}

static void nfs_free_delegation(struct nfs_delegation *delegation)
{
	struct rpc_cred *cred;

	cred = rcu_dereference(delegation->cred);
	rcu_assign_pointer(delegation->cred, NULL);
	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	if (cred)
		put_rpccred(cred);
}

void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
{
	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
}

int nfs_have_delegation(struct inode *inode, fmode_t flags)
{
	struct nfs_delegation *delegation;
	int ret = 0;

	flags &= FMODE_READ|FMODE_WRITE;
	rcu_read_lock();
	delegation = rcu_dereference(NFS_I(inode)->delegation);
	if (delegation != NULL && (delegation->type & flags) == flags) {
		nfs_mark_delegation_referenced(delegation);
		ret = 1;
	}
	rcu_read_unlock();
	return ret;
}

static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
{
	struct inode *inode = state->inode;
	struct file_lock *fl;
	int status = 0;

	if (inode->i_flock == NULL)
		goto out;

	/* Protect inode->i_flock using the BKL */
	lock_kernel();
	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
		if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
			continue;
		if (nfs_file_open_context(fl->fl_file) != ctx)
			continue;
		unlock_kernel();
		status = nfs4_lock_delegation_recall(state, fl);
		if (status < 0)
			goto out;
		lock_kernel();
	}
	unlock_kernel();
out:
	return status;
}

static 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>
1da177e4 LT	12	#include <linux/sched.h>
405f5571	13	#include <linux/smp_lock.h>
1da177e4 LT	14	#include <linux/spinlock.h>
	15
	16	#include <linux/nfs4.h>
	17	#include <linux/nfs_fs.h>
	18	#include <linux/nfs_xdr.h>
	19
4ce79717	20	#include "nfs4_fs.h"
1da177e4	21	#include "delegation.h"
24c8dbbb	22	#include "internal.h"
1da177e4	23
905f8d16	24	static void nfs_do_free_delegation(struct nfs_delegation *delegation)
1da177e4	25	{
1da177e4 LT	26	kfree(delegation);
	27	}
	28
8383e460 TM	29	static void nfs_free_delegation_callback(struct rcu_head *head)
	30	{
	31	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
	32
905f8d16 TM	33	nfs_do_free_delegation(delegation);
	34	}
	35
	36	static void nfs_free_delegation(struct nfs_delegation *delegation)
	37	{
	38	struct rpc_cred *cred;
	39
	40	cred = rcu_dereference(delegation->cred);
	41	rcu_assign_pointer(delegation->cred, NULL);
	42	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
	43	if (cred)
	44	put_rpccred(cred);
8383e460 TM	45	}
8383e460 TM	46
b7391f44 TM	47	void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
	48	{
	49	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
	50	}
	51
bd7bf9d5	52	int nfs_have_delegation(struct inode *inode, fmode_t flags)
b7391f44 TM	53	{
	54	struct nfs_delegation *delegation;
	55	int ret = 0;
	56
	57	flags &= FMODE_READ\|FMODE_WRITE;
	58	rcu_read_lock();
	59	delegation = rcu_dereference(NFS_I(inode)->delegation);
	60	if (delegation != NULL && (delegation->type & flags) == flags) {
	61	nfs_mark_delegation_referenced(delegation);
	62	ret = 1;
	63	}
	64	rcu_read_unlock();
	65	return ret;
	66	}
	67
888e694c TM	68	static int nfs_delegation_claim_locks(struct nfs_open_context ctx, struct nfs4_state state)
	69	{
	70	struct inode *inode = state->inode;
	71	struct file_lock *fl;
d5122201	72	int status = 0;
888e694c	73
3f09df70 TM	74	if (inode->i_flock == NULL)
	75	goto out;
	76
	77	/* Protect inode->i_flock using the BKL */
	78	lock_kernel();
90dc7d27	79	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
888e694c TM	80	if (!(fl->fl_flags & (FL_POSIX\|FL_FLOCK)))
888e694c TM	81	continue;
cd3758e3	82	if (nfs_file_open_context(fl->fl_file) != ctx)
888e694c	83	continue;
3f09df70	84	unlock_kernel();
888e694c	85	status = nfs4_lock_delegation_recall(state, fl);
d5122201	86	if (status < 0)
3f09df70 TM	87	goto out;
3f09df70 TM	88	lock_kernel();
888e694c	89	}
3f09df70 TM	90	unlock_kernel();
3f09df70 TM	91	out:
888e694c TM	92	return status;
	93	}
	94
90163027	95	static void nfs_delegation_claim_opens(struct inode inode, const nfs4_stateid stateid)
1da177e4 LT	96	{
	97	struct nfs_inode *nfsi = NFS_I(inode);
	98	struct nfs_open_context *ctx;
	99	struct nfs4_state *state;
888e694c	100	int err;
1da177e4 LT	101
	102	again:
	103	spin_lock(&inode->i_lock);
	104	list_for_each_entry(ctx, &nfsi->open_files, list) {
	105	state = ctx->state;
	106	if (state == NULL)
	107	continue;
	108	if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
	109	continue;
90163027 TM	110	if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
90163027 TM	111	continue;
1da177e4 LT	112	get_nfs_open_context(ctx);
1da177e4 LT	113	spin_unlock(&inode->i_lock);
13437e12	114	err = nfs4_open_delegation_recall(ctx, state, stateid);
888e694c TM	115	if (err >= 0)
888e694c TM	116	err = nfs_delegation_claim_locks(ctx, state);
1da177e4	117	put_nfs_open_context(ctx);
888e694c TM	118	if (err != 0)
888e694c TM	119	return;
1da177e4 LT	120	goto again;
	121	}
	122	spin_unlock(&inode->i_lock);
	123	}
	124
	125	/*
	126	* Set up a delegation on an inode
	127	*/
	128	void nfs_inode_reclaim_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	129	{
	130	struct nfs_delegation *delegation = NFS_I(inode)->delegation;
05c88bab	131	struct rpc_cred *oldcred;
1da177e4 LT	132
	133	if (delegation == NULL)
	134	return;
	135	memcpy(delegation->stateid.data, res->delegation.data,
	136	sizeof(delegation->stateid.data));
	137	delegation->type = res->delegation_type;
	138	delegation->maxsize = res->maxsize;
05c88bab	139	oldcred = delegation->cred;
1da177e4	140	delegation->cred = get_rpccred(cred);
15c831bf	141	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1da177e4 LT	142	NFS_I(inode)->delegation_state = delegation->type;
1da177e4 LT	143	smp_wmb();
05c88bab	144	put_rpccred(oldcred);
1da177e4 LT	145	}
1da177e4 LT	146
57bfa891 TM	147	static int nfs_do_return_delegation(struct inode inode, struct nfs_delegation delegation, int issync)
	148	{
	149	int res = 0;
	150
	151	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
	152	nfs_free_delegation(delegation);
	153	return res;
	154	}
	155
86e89489 TM	156	static struct inode nfs_delegation_grab_inode(struct nfs_delegation delegation)
	157	{
	158	struct inode *inode = NULL;
	159
	160	spin_lock(&delegation->lock);
	161	if (delegation->inode != NULL)
	162	inode = igrab(delegation->inode);
	163	spin_unlock(&delegation->lock);
	164	return inode;
	165	}
	166
57bfa891 TM	167	static struct nfs_delegation nfs_detach_delegation_locked(struct nfs_inode nfsi, const nfs4_stateid *stateid)
	168	{
	169	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
	170
	171	if (delegation == NULL)
	172	goto nomatch;
34310430	173	spin_lock(&delegation->lock);
57bfa891 TM	174	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
57bfa891 TM	175	sizeof(delegation->stateid.data)) != 0)
34310430	176	goto nomatch_unlock;
57bfa891	177	list_del_rcu(&delegation->super_list);
86e89489	178	delegation->inode = NULL;
57bfa891 TM	179	nfsi->delegation_state = 0;
57bfa891 TM	180	rcu_assign_pointer(nfsi->delegation, NULL);
34310430	181	spin_unlock(&delegation->lock);
57bfa891	182	return delegation;
34310430 TM	183	nomatch_unlock:
34310430 TM	184	spin_unlock(&delegation->lock);
57bfa891 TM	185	nomatch:
	186	return NULL;
	187	}
	188
1da177e4 LT	189	/*
	190	* Set up a delegation on an inode
	191	*/
	192	int nfs_inode_set_delegation(struct inode inode, struct rpc_cred cred, struct nfs_openres *res)
	193	{
7539bbab	194	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1da177e4 LT	195	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	196	struct nfs_delegation *delegation;
57bfa891	197	struct nfs_delegation *freeme = NULL;
1da177e4 LT	198	int status = 0;
1da177e4 LT	199
f52720ca	200	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
1da177e4 LT	201	if (delegation == NULL)
	202	return -ENOMEM;
	203	memcpy(delegation->stateid.data, res->delegation.data,
	204	sizeof(delegation->stateid.data));
	205	delegation->type = res->delegation_type;
	206	delegation->maxsize = res->maxsize;
beb2a5ec	207	delegation->change_attr = nfsi->change_attr;
1da177e4 LT	208	delegation->cred = get_rpccred(cred);
1da177e4 LT	209	delegation->inode = inode;
b7391f44	210	delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
34310430	211	spin_lock_init(&delegation->lock);
1da177e4 LT	212
1da177e4 LT	213	spin_lock(&clp->cl_lock);
57bfa891	214	if (rcu_dereference(nfsi->delegation) != NULL) {
1da177e4	215	if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
57bfa891 TM	216	sizeof(delegation->stateid)) == 0 &&
	217	delegation->type == nfsi->delegation->type) {
	218	goto out;
1da177e4	219	}
57bfa891 TM	220	/*
	221	* Deal with broken servers that hand out two
	222	* delegations for the same file.
	223	*/
	224	dfprintk(FILE, "%s: server %s handed out "
	225	"a duplicate delegation!\n",
3110ff80	226	__func__, clp->cl_hostname);
57bfa891 TM	227	if (delegation->type <= nfsi->delegation->type) {
	228	freeme = delegation;
	229	delegation = NULL;
	230	goto out;
	231	}
	232	freeme = nfs_detach_delegation_locked(nfsi, NULL);
1da177e4	233	}
57bfa891 TM	234	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
	235	nfsi->delegation_state = delegation->type;
	236	rcu_assign_pointer(nfsi->delegation, delegation);
	237	delegation = NULL;
412c77ce TM	238
	239	/* Ensure we revalidate the attributes and page cache! */
	240	spin_lock(&inode->i_lock);
	241	nfsi->cache_validity \|= NFS_INO_REVAL_FORCED;
	242	spin_unlock(&inode->i_lock);
	243
57bfa891	244	out:
1da177e4	245	spin_unlock(&clp->cl_lock);
603c83da TM	246	if (delegation != NULL)
603c83da TM	247	nfs_free_delegation(delegation);
57bfa891 TM	248	if (freeme != NULL)
57bfa891 TM	249	nfs_do_return_delegation(inode, freeme, 0);
1da177e4 LT	250	return status;
	251	}
	252
1da177e4 LT	253	/* Sync all data to disk upon delegation return */
	254	static void nfs_msync_inode(struct inode *inode)
	255	{
	256	filemap_fdatawrite(inode->i_mapping);
	257	nfs_wb_all(inode);
	258	filemap_fdatawait(inode->i_mapping);
	259	}
	260
	261	/*
	262	* Basic procedure for returning a delegation to the server
	263	*/
90163027	264	static int __nfs_inode_return_delegation(struct inode inode, struct nfs_delegation delegation)
1da177e4	265	{
1da177e4	266	struct nfs_inode *nfsi = NFS_I(inode);
1da177e4 LT	267
1da177e4 LT	268	nfs_msync_inode(inode);
3f09df70 TM	269	/*
	270	* Guard against new delegated open/lock/unlock calls and against
	271	* state recovery
	272	*/
1da177e4	273	down_write(&nfsi->rwsem);
90163027	274	nfs_delegation_claim_opens(inode, &delegation->stateid);
1da177e4	275	up_write(&nfsi->rwsem);
1da177e4 LT	276	nfs_msync_inode(inode);
1da177e4 LT	277
e6f81075	278	return nfs_do_return_delegation(inode, delegation, 1);
90163027 TM	279	}
90163027 TM	280
515d8611 TM	281	/*
	282	* Return all delegations that have been marked for return
	283	*/
707fb4b3	284	void nfs_client_return_marked_delegations(struct nfs_client *clp)
515d8611 TM	285	{
	286	struct nfs_delegation *delegation;
	287	struct inode *inode;
	288
	289	restart:
	290	rcu_read_lock();
	291	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	292	if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
	293	continue;
	294	inode = nfs_delegation_grab_inode(delegation);
	295	if (inode == NULL)
	296	continue;
	297	spin_lock(&clp->cl_lock);
	298	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
	299	spin_unlock(&clp->cl_lock);
	300	rcu_read_unlock();
	301	if (delegation != NULL)
	302	__nfs_inode_return_delegation(inode, delegation);
	303	iput(inode);
	304	goto restart;
	305	}
	306	rcu_read_unlock();
	307	}
	308
e6f81075 TM	309	/*
	310	* This function returns the delegation without reclaiming opens
	311	* or protecting against delegation reclaims.
	312	* It is therefore really only safe to be called from
	313	* nfs4_clear_inode()
	314	*/
	315	void nfs_inode_return_delegation_noreclaim(struct inode *inode)
	316	{
	317	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	318	struct nfs_inode *nfsi = NFS_I(inode);
	319	struct nfs_delegation *delegation;
	320
	321	if (rcu_dereference(nfsi->delegation) != NULL) {
	322	spin_lock(&clp->cl_lock);
	323	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	324	spin_unlock(&clp->cl_lock);
	325	if (delegation != NULL)
	326	nfs_do_return_delegation(inode, delegation, 0);
	327	}
	328	}
	329
90163027 TM	330	int nfs_inode_return_delegation(struct inode *inode)
	331	{
	332	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
	333	struct nfs_inode *nfsi = NFS_I(inode);
	334	struct nfs_delegation *delegation;
	335	int err = 0;
	336
8383e460	337	if (rcu_dereference(nfsi->delegation) != NULL) {
90163027 TM	338	spin_lock(&clp->cl_lock);
	339	delegation = nfs_detach_delegation_locked(nfsi, NULL);
	340	spin_unlock(&clp->cl_lock);
	341	if (delegation != NULL)
	342	err = __nfs_inode_return_delegation(inode, delegation);
	343	}
	344	return err;
1da177e4 LT	345	}
1da177e4 LT	346
6411bd4a TM	347	static void nfs_mark_return_delegation(struct nfs_client clp, struct nfs_delegation delegation)
	348	{
	349	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
	350	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	351	}
	352
1da177e4 LT	353	/*
	354	* Return all delegations associated to a super block
	355	*/
515d8611	356	void nfs_super_return_all_delegations(struct super_block *sb)
1da177e4	357	{
7539bbab	358	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
1da177e4	359	struct nfs_delegation *delegation;
1da177e4 LT	360
	361	if (clp == NULL)
	362	return;
8383e460 TM	363	rcu_read_lock();
8383e460 TM	364	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	365	spin_lock(&delegation->lock);
86e89489 TM	366	if (delegation->inode != NULL && delegation->inode->i_sb == sb)
515d8611	367	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
86e89489	368	spin_unlock(&delegation->lock);
1da177e4	369	}
8383e460	370	rcu_read_unlock();
515d8611 TM	371	nfs_client_return_marked_delegations(clp);
	372	}
	373
707fb4b3	374	static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
515d8611 TM	375	{
	376	struct nfs_delegation *delegation;
	377
	378	rcu_read_lock();
707fb4b3	379	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
515d8611	380	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
707fb4b3 TM	381	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
707fb4b3 TM	382	}
515d8611	383	rcu_read_unlock();
1da177e4 LT	384	}
1da177e4 LT	385
b0d3ded1	386	static void nfs_delegation_run_state_manager(struct nfs_client *clp)
58d9714a	387	{
b0d3ded1 TM	388	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
b0d3ded1 TM	389	nfs4_schedule_state_manager(clp);
58d9714a TM	390	}
58d9714a TM	391
adfa6f98	392	void nfs_expire_all_delegations(struct nfs_client *clp)
58d9714a	393	{
b0d3ded1 TM	394	nfs_client_mark_return_all_delegations(clp);
b0d3ded1 TM	395	nfs_delegation_run_state_manager(clp);
58d9714a TM	396	}
58d9714a TM	397
1da177e4 LT	398	/*
	399	* Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
	400	*/
adfa6f98	401	void nfs_handle_cb_pathdown(struct nfs_client *clp)
1da177e4	402	{
1da177e4 LT	403	if (clp == NULL)
1da177e4 LT	404	return;
707fb4b3	405	nfs_client_mark_return_all_delegations(clp);
1da177e4 LT	406	}
1da177e4 LT	407
b7391f44 TM	408	static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
	409	{
	410	struct nfs_delegation *delegation;
	411
	412	rcu_read_lock();
	413	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
	414	if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
	415	continue;
	416	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
	417	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
	418	}
	419	rcu_read_unlock();
	420	}
	421
	422	void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
	423	{
	424	nfs_client_mark_return_unreferenced_delegations(clp);
	425	nfs_delegation_run_state_manager(clp);
	426	}
	427
1da177e4 LT	428	/*
	429	* Asynchronous delegation recall!
	430	*/
	431	int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid)
	432	{
6411bd4a TM	433	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
6411bd4a TM	434	struct nfs_delegation *delegation;
1da177e4	435
6411bd4a TM	436	rcu_read_lock();
	437	delegation = rcu_dereference(NFS_I(inode)->delegation);
	438	if (delegation == NULL \|\| memcmp(delegation->stateid.data, stateid->data,
	439	sizeof(delegation->stateid.data)) != 0) {
	440	rcu_read_unlock();
	441	return -ENOENT;
	442	}
	443	nfs_mark_return_delegation(clp, delegation);
	444	rcu_read_unlock();
	445	nfs_delegation_run_state_manager(clp);
	446	return 0;
1da177e4 LT	447	}
	448
	449	/*
	450	* Retrieve the inode associated with a delegation
	451	*/
adfa6f98	452	struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh *fhandle)
1da177e4 LT	453	{
	454	struct nfs_delegation *delegation;
	455	struct inode *res = NULL;
8383e460 TM	456	rcu_read_lock();
8383e460 TM	457	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
86e89489 TM	458	spin_lock(&delegation->lock);
	459	if (delegation->inode != NULL &&
	460	nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1da177e4	461	res = igrab(delegation->inode);
1da177e4	462	}
86e89489 TM	463	spin_unlock(&delegation->lock);
	464	if (res != NULL)
	465	break;
1da177e4	466	}
8383e460	467	rcu_read_unlock();
1da177e4 LT	468	return res;
	469	}
	470
	471	/*
	472	* Mark all delegations as needing to be reclaimed
	473	*/
adfa6f98	474	void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1da177e4 LT	475	{
1da177e4 LT	476	struct nfs_delegation *delegation;
8383e460 TM	477	rcu_read_lock();
8383e460 TM	478	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
15c831bf	479	set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
8383e460	480	rcu_read_unlock();
1da177e4 LT	481	}
	482
	483	/*
	484	* Reap all unclaimed delegations after reboot recovery is done
	485	*/
adfa6f98	486	void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1da177e4	487	{
8383e460	488	struct nfs_delegation *delegation;
86e89489	489	struct inode *inode;
8383e460 TM	490	restart:
	491	rcu_read_lock();
	492	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
15c831bf	493	if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
1da177e4	494	continue;
86e89489 TM	495	inode = nfs_delegation_grab_inode(delegation);
	496	if (inode == NULL)
	497	continue;
8383e460	498	spin_lock(&clp->cl_lock);
86e89489	499	delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
8383e460 TM	500	spin_unlock(&clp->cl_lock);
	501	rcu_read_unlock();
	502	if (delegation != NULL)
905f8d16	503	nfs_free_delegation(delegation);
86e89489	504	iput(inode);
8383e460	505	goto restart;
1da177e4	506	}
8383e460	507	rcu_read_unlock();
1da177e4	508	}
3e4f6290 TM	509
	510	int nfs4_copy_delegation_stateid(nfs4_stateid dst, struct inode inode)
	511	{
3e4f6290 TM	512	struct nfs_inode *nfsi = NFS_I(inode);
3e4f6290 TM	513	struct nfs_delegation *delegation;
8383e460	514	int ret = 0;
3e4f6290	515
8383e460 TM	516	rcu_read_lock();
8383e460 TM	517	delegation = rcu_dereference(nfsi->delegation);
3e4f6290 TM	518	if (delegation != NULL) {
3e4f6290 TM	519	memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
8383e460	520	ret = 1;
3e4f6290	521	}
8383e460 TM	522	rcu_read_unlock();
8383e460 TM	523	return ret;
3e4f6290	524	}