[linux-2.6-block.git] / fs / nfs / pnfs_dev.c

/*
 *  Device operations for the pnfs client.
 *
 *  Copyright (c) 2002
 *  The Regents of the University of Michigan
 *  All Rights Reserved
 *
 *  Dean Hildebrand <dhildebz@umich.edu>
 *  Garth Goodson   <Garth.Goodson@netapp.com>
 *
 *  Permission is granted to use, copy, create derivative works, and
 *  redistribute this software and such derivative works for any purpose,
 *  so long as the name of the University of Michigan is not used in
 *  any advertising or publicity pertaining to the use or distribution
 *  of this software without specific, written prior authorization. If
 *  the above copyright notice or any other identification of the
 *  University of Michigan is included in any copy of any portion of
 *  this software, then the disclaimer below must also be included.
 *
 *  This software is provided as is, without representation or warranty
 *  of any kind either express or implied, including without limitation
 *  the implied warranties of merchantability, fitness for a particular
 *  purpose, or noninfringement.  The Regents of the University of
 *  Michigan shall not be liable for any damages, including special,
 *  indirect, incidental, or consequential damages, with respect to any
 *  claim arising out of or in connection with the use of the software,
 *  even if it has been or is hereafter advised of the possibility of
 *  such damages.
 */

#include <linux/export.h>
#include "pnfs.h"

#define NFSDBG_FACILITY		NFSDBG_PNFS

/*
 * Device ID RCU cache. A device ID is unique per server and layout type.
 */
#define NFS4_DEVICE_ID_HASH_BITS	5
#define NFS4_DEVICE_ID_HASH_SIZE	(1 << NFS4_DEVICE_ID_HASH_BITS)
#define NFS4_DEVICE_ID_HASH_MASK	(NFS4_DEVICE_ID_HASH_SIZE - 1)

static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
static DEFINE_SPINLOCK(nfs4_deviceid_lock);

#ifdef NFS_DEBUG
void
nfs4_print_deviceid(const struct nfs4_deviceid *id)
{
	u32 *p = (u32 *)id;

	dprintk("%s: device id= [%x%x%x%x]\n", __func__,
		p[0], p[1], p[2], p[3]);
}
EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
#endif

static inline u32
nfs4_deviceid_hash(const struct nfs4_deviceid *id)
{
	unsigned char *cptr = (unsigned char *)id->data;
	unsigned int nbytes = NFS4_DEVICEID4_SIZE;
	u32 x = 0;

	while (nbytes--) {
		x *= 37;
		x += *cptr++;
	}
	return x & NFS4_DEVICE_ID_HASH_MASK;
}

static struct nfs4_deviceid_node *
_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
		 const struct nfs_client *clp, const struct nfs4_deviceid *id,
		 long hash)
{
	struct nfs4_deviceid_node *d;
	struct hlist_node *n;

	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
		if (d->ld == ld && d->nfs_client == clp &&
		    !memcmp(&d->deviceid, id, sizeof(*id))) {
			if (atomic_read(&d->ref))
				return d;
			else
				continue;
		}
	return NULL;
}

/*
 * Lookup a deviceid in cache and get a reference count on it if found
 *
 * @clp nfs_client associated with deviceid
 * @id deviceid to look up
 */
static struct nfs4_deviceid_node *
_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
		   const struct nfs_client *clp, const struct nfs4_deviceid *id,
		   long hash)
{
	struct nfs4_deviceid_node *d;

	rcu_read_lock();
	d = _lookup_deviceid(ld, clp, id, hash);
	if (d != NULL)
		atomic_inc(&d->ref);
	rcu_read_unlock();
	return d;
}

struct nfs4_deviceid_node *
nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
		       const struct nfs_client *clp, const struct nfs4_deviceid *id)
{
	return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
}
EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);

/*
 * Remove a deviceid from cache
 *
 * @clp nfs_client associated with deviceid
 * @id the deviceid to unhash
 *
 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
 */
void
nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
			 const struct nfs_client *clp, const struct nfs4_deviceid *id)
{
	struct nfs4_deviceid_node *d;

	spin_lock(&nfs4_deviceid_lock);
	rcu_read_lock();
	d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
	rcu_read_unlock();
	if (!d) {
		spin_unlock(&nfs4_deviceid_lock);
		return;
	}
	hlist_del_init_rcu(&d->node);
	spin_unlock(&nfs4_deviceid_lock);
	synchronize_rcu();

	/* balance the initial ref set in pnfs_insert_deviceid */
	if (atomic_dec_and_test(&d->ref))
		d->ld->free_deviceid_node(d);
}
EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);

void
nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
			const struct pnfs_layoutdriver_type *ld,
			const struct nfs_client *nfs_client,
			const struct nfs4_deviceid *id)
{
	INIT_HLIST_NODE(&d->node);
	INIT_HLIST_NODE(&d->tmpnode);
	d->ld = ld;
	d->nfs_client = nfs_client;
	d->flags = 0;
	d->deviceid = *id;
	atomic_set(&d->ref, 1);
}
EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);

/*
 * Uniquely initialize and insert a deviceid node into cache
 *
 * @new new deviceid node
 *      Note that the caller must set up the following members:
 *        new->ld
 *        new->nfs_client
 *        new->deviceid
 *
 * @ret the inserted node, if none found, otherwise, the found entry.
 */
struct nfs4_deviceid_node *
nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
{
	struct nfs4_deviceid_node *d;
	long hash;

	spin_lock(&nfs4_deviceid_lock);
	hash = nfs4_deviceid_hash(&new->deviceid);
	d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash);
	if (d) {
		spin_unlock(&nfs4_deviceid_lock);
		return d;
	}

	hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
	spin_unlock(&nfs4_deviceid_lock);
	atomic_inc(&new->ref);

	return new;
}
EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);

/*
 * Dereference a deviceid node and delete it when its reference count drops
 * to zero.
 *
 * @d deviceid node to put
 *
 * return true iff the node was deleted
 * Note that since the test for d->ref == 0 is sufficient to establish
 * that the node is no longer hashed in the global device id cache.
 */
bool
nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
{
	if (!atomic_dec_and_test(&d->ref))
		return false;
	d->ld->free_deviceid_node(d);
	return true;
}
EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);

static void
_deviceid_purge_client(const struct nfs_client *clp, long hash)
{
	struct nfs4_deviceid_node *d;
	struct hlist_node *n;
	HLIST_HEAD(tmp);

	spin_lock(&nfs4_deviceid_lock);
	rcu_read_lock();
	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
		if (d->nfs_client == clp && atomic_read(&d->ref)) {
			hlist_del_init_rcu(&d->node);
			hlist_add_head(&d->tmpnode, &tmp);
		}
	rcu_read_unlock();
	spin_unlock(&nfs4_deviceid_lock);

	if (hlist_empty(&tmp))
		return;

	synchronize_rcu();
	while (!hlist_empty(&tmp)) {
		d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
		hlist_del(&d->tmpnode);
		if (atomic_dec_and_test(&d->ref))
			d->ld->free_deviceid_node(d);
	}
}

void
nfs4_deviceid_purge_client(const struct nfs_client *clp)
{
	long h;

	if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
		return;
	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
		_deviceid_purge_client(clp, h);
}

/*
 * Stop use of all deviceids associated with an nfs_client
 */
void
nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
{
	struct nfs4_deviceid_node *d;
	struct hlist_node *n;
	int i;

	rcu_read_lock();
	for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
		hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[i], node)
			if (d->nfs_client == clp)
				set_bit(NFS_DEVICEID_INVALID, &d->flags);
	}
	rcu_read_unlock();
}
Commit	Line	Data
a1eaecbc BH	1	/*
	2	* Device operations for the pnfs client.
	3	*
	4	* Copyright (c) 2002
	5	* The Regents of the University of Michigan
	6	* All Rights Reserved
	7	*
	8	* Dean Hildebrand <dhildebz@umich.edu>
	9	* Garth Goodson <Garth.Goodson@netapp.com>
	10	*
	11	* Permission is granted to use, copy, create derivative works, and
	12	* redistribute this software and such derivative works for any purpose,
	13	* so long as the name of the University of Michigan is not used in
	14	* any advertising or publicity pertaining to the use or distribution
	15	* of this software without specific, written prior authorization. If
	16	* the above copyright notice or any other identification of the
	17	* University of Michigan is included in any copy of any portion of
	18	* this software, then the disclaimer below must also be included.
	19	*
	20	* This software is provided as is, without representation or warranty
	21	* of any kind either express or implied, including without limitation
	22	* the implied warranties of merchantability, fitness for a particular
	23	* purpose, or noninfringement. The Regents of the University of
	24	* Michigan shall not be liable for any damages, including special,
	25	* indirect, incidental, or consequential damages, with respect to any
	26	* claim arising out of or in connection with the use of the software,
	27	* even if it has been or is hereafter advised of the possibility of
	28	* such damages.
	29	*/
	30
afeacc8c	31	#include <linux/export.h>
a1eaecbc BH	32	#include "pnfs.h"
	33
	34	#define NFSDBG_FACILITY NFSDBG_PNFS
	35
	36	/*
	37	* Device ID RCU cache. A device ID is unique per server and layout type.
	38	*/
	39	#define NFS4_DEVICE_ID_HASH_BITS 5
	40	#define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS)
	41	#define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1)
	42
	43	static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
	44	static DEFINE_SPINLOCK(nfs4_deviceid_lock);
	45
6f00866d	46	#ifdef NFS_DEBUG
a1eaecbc BH	47	void
	48	nfs4_print_deviceid(const struct nfs4_deviceid *id)
	49	{
	50	u32 p = (u32 )id;
	51
	52	dprintk("%s: device id= [%x%x%x%x]\n", __func__,
	53	p[0], p[1], p[2], p[3]);
	54	}
	55	EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
6f00866d	56	#endif
a1eaecbc BH	57
	58	static inline u32
	59	nfs4_deviceid_hash(const struct nfs4_deviceid *id)
	60	{
	61	unsigned char cptr = (unsigned char )id->data;
	62	unsigned int nbytes = NFS4_DEVICEID4_SIZE;
	63	u32 x = 0;
	64
	65	while (nbytes--) {
	66	x *= 37;
	67	x += *cptr++;
	68	}
	69	return x & NFS4_DEVICE_ID_HASH_MASK;
	70	}
	71
1be5683b	72	static struct nfs4_deviceid_node *
35c8bb54 BH	73	_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	74	const struct nfs_client clp, const struct nfs4_deviceid id,
1be5683b ME	75	long hash)
	76	{
	77	struct nfs4_deviceid_node *d;
	78	struct hlist_node *n;
	79
	80	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
35c8bb54 BH	81	if (d->ld == ld && d->nfs_client == clp &&
35c8bb54 BH	82	!memcmp(&d->deviceid, id, sizeof(*id))) {
1be5683b ME	83	if (atomic_read(&d->ref))
	84	return d;
	85	else
	86	continue;
	87	}
	88	return NULL;
	89	}
	90
a1eaecbc BH	91	/*
	92	* Lookup a deviceid in cache and get a reference count on it if found
	93	*
	94	* @clp nfs_client associated with deviceid
	95	* @id deviceid to look up
	96	*/
17280175	97	static struct nfs4_deviceid_node *
35c8bb54 BH	98	_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	99	const struct nfs_client clp, const struct nfs4_deviceid id,
1be5683b ME	100	long hash)
	101	{
	102	struct nfs4_deviceid_node *d;
	103
	104	rcu_read_lock();
35c8bb54	105	d = _lookup_deviceid(ld, clp, id, hash);
47cb498e TM	106	if (d != NULL)
47cb498e TM	107	atomic_inc(&d->ref);
1be5683b ME	108	rcu_read_unlock();
	109	return d;
	110	}
	111
a1eaecbc	112	struct nfs4_deviceid_node *
35c8bb54 BH	113	nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	114	const struct nfs_client clp, const struct nfs4_deviceid id)
1be5683b	115	{
35c8bb54	116	return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
1be5683b ME	117	}
	118	EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
	119
	120	/*
47cb498e	121	* Remove a deviceid from cache
1be5683b ME	122	*
	123	* @clp nfs_client associated with deviceid
	124	* @id the deviceid to unhash
	125	*
	126	* @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
	127	*/
47cb498e TM	128	void
47cb498e TM	129	nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54	130	const struct nfs_client clp, const struct nfs4_deviceid id)
a1eaecbc BH	131	{
a1eaecbc BH	132	struct nfs4_deviceid_node *d;
a1eaecbc	133
1be5683b	134	spin_lock(&nfs4_deviceid_lock);
a1eaecbc	135	rcu_read_lock();
35c8bb54	136	d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
a1eaecbc	137	rcu_read_unlock();
1be5683b ME	138	if (!d) {
1be5683b ME	139	spin_unlock(&nfs4_deviceid_lock);
47cb498e	140	return;
1be5683b ME	141	}
	142	hlist_del_init_rcu(&d->node);
	143	spin_unlock(&nfs4_deviceid_lock);
	144	synchronize_rcu();
	145
	146	/* balance the initial ref set in pnfs_insert_deviceid */
	147	if (atomic_dec_and_test(&d->ref))
47cb498e	148	d->ld->free_deviceid_node(d);
1be5683b ME	149	}
1be5683b ME	150	EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
a1eaecbc BH	151
	152	void
	153	nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
1775bc34	154	const struct pnfs_layoutdriver_type *ld,
a1eaecbc BH	155	const struct nfs_client *nfs_client,
	156	const struct nfs4_deviceid *id)
	157	{
1775bc34	158	INIT_HLIST_NODE(&d->node);
9e3bd4e2	159	INIT_HLIST_NODE(&d->tmpnode);
1775bc34	160	d->ld = ld;
a1eaecbc	161	d->nfs_client = nfs_client;
c47abcf8	162	d->flags = 0;
a1eaecbc	163	d->deviceid = *id;
1775bc34	164	atomic_set(&d->ref, 1);
a1eaecbc BH	165	}
	166	EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
	167
	168	/*
	169	* Uniquely initialize and insert a deviceid node into cache
	170	*
	171	* @new new deviceid node
1775bc34 BH	172	* Note that the caller must set up the following members:
	173	* new->ld
	174	* new->nfs_client
	175	* new->deviceid
a1eaecbc BH	176	*
	177	* @ret the inserted node, if none found, otherwise, the found entry.
	178	*/
	179	struct nfs4_deviceid_node *
	180	nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
	181	{
	182	struct nfs4_deviceid_node *d;
	183	long hash;
	184
	185	spin_lock(&nfs4_deviceid_lock);
1be5683b	186	hash = nfs4_deviceid_hash(&new->deviceid);
35c8bb54	187	d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash);
a1eaecbc BH	188	if (d) {
	189	spin_unlock(&nfs4_deviceid_lock);
	190	return d;
	191	}
	192
a1eaecbc BH	193	hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
a1eaecbc BH	194	spin_unlock(&nfs4_deviceid_lock);
1d92a08d	195	atomic_inc(&new->ref);
a1eaecbc BH	196
	197	return new;
	198	}
	199	EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
	200
	201	/*
	202	* Dereference a deviceid node and delete it when its reference count drops
	203	* to zero.
	204	*
	205	* @d deviceid node to put
	206	*
47cb498e TM	207	* return true iff the node was deleted
	208	* Note that since the test for d->ref == 0 is sufficient to establish
	209	* that the node is no longer hashed in the global device id cache.
a1eaecbc BH	210	*/
	211	bool
	212	nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
	213	{
47cb498e	214	if (!atomic_dec_and_test(&d->ref))
a1eaecbc	215	return false;
1775bc34	216	d->ld->free_deviceid_node(d);
a1eaecbc BH	217	return true;
	218	}
	219	EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
1775bc34 BH	220
	221	static void
	222	_deviceid_purge_client(const struct nfs_client *clp, long hash)
	223	{
	224	struct nfs4_deviceid_node *d;
9e3bd4e2	225	struct hlist_node *n;
1775bc34 BH	226	HLIST_HEAD(tmp);
1775bc34 BH	227
9e3bd4e2	228	spin_lock(&nfs4_deviceid_lock);
1775bc34 BH	229	rcu_read_lock();
	230	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
	231	if (d->nfs_client == clp && atomic_read(&d->ref)) {
	232	hlist_del_init_rcu(&d->node);
9e3bd4e2	233	hlist_add_head(&d->tmpnode, &tmp);
1775bc34 BH	234	}
1775bc34 BH	235	rcu_read_unlock();
9e3bd4e2	236	spin_unlock(&nfs4_deviceid_lock);
1775bc34 BH	237
	238	if (hlist_empty(&tmp))
	239	return;
	240
	241	synchronize_rcu();
9e3bd4e2 WAA	242	while (!hlist_empty(&tmp)) {
	243	d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
	244	hlist_del(&d->tmpnode);
1775bc34 BH	245	if (atomic_dec_and_test(&d->ref))
1775bc34 BH	246	d->ld->free_deviceid_node(d);
9e3bd4e2	247	}
1775bc34 BH	248	}
	249
	250	void
	251	nfs4_deviceid_purge_client(const struct nfs_client *clp)
	252	{
	253	long h;
	254
9e3bd4e2 WAA	255	if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
9e3bd4e2 WAA	256	return;
1775bc34 BH	257	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
1775bc34 BH	258	_deviceid_purge_client(clp, h);
1775bc34	259	}
c47abcf8 AA	260
	261	/*
	262	* Stop use of all deviceids associated with an nfs_client
	263	*/
	264	void
	265	nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
	266	{
	267	struct nfs4_deviceid_node *d;
	268	struct hlist_node *n;
	269	int i;
	270
	271	rcu_read_lock();
	272	for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
	273	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[i], node)
	274	if (d->nfs_client == clp)
	275	set_bit(NFS_DEVICEID_INVALID, &d->flags);
	276	}
	277	rcu_read_unlock();
	278	}