[GitHub/mt8127/android_kernel_alcatel_ttab.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 "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);

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);

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
 */
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 && !atomic_inc_not_zero(&d->ref))
		d = NULL;
	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);

/*
 * Unhash and put deviceid
 *
 * @clp nfs_client associated with deviceid
 * @id the deviceid to unhash
 *
 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
 */
struct nfs4_deviceid_node *
nfs4_unhash_put_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 NULL;
	}
	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))
		return d;

	return NULL;
}
EXPORT_SYMBOL_GPL(nfs4_unhash_put_deviceid);

/*
 * Delete a deviceid from cache
 *
 * @clp struct nfs_client qualifying the deviceid
 * @id deviceid to delete
 */
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;

	d = nfs4_unhash_put_deviceid(ld, clp, id);
	if (!d)
		return;
	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->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
 *
 * @ret true iff the node was deleted
 */
bool
nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
{
	if (!atomic_dec_and_lock(&d->ref, &nfs4_deviceid_lock))
		return false;
	hlist_del_init_rcu(&d->node);
	spin_unlock(&nfs4_deviceid_lock);
	synchronize_rcu();
	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);
}
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
	31	#include "pnfs.h"
	32
	33	#define NFSDBG_FACILITY NFSDBG_PNFS
	34
	35	/*
	36	* Device ID RCU cache. A device ID is unique per server and layout type.
	37	*/
	38	#define NFS4_DEVICE_ID_HASH_BITS 5
	39	#define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS)
	40	#define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1)
	41
	42	static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
	43	static DEFINE_SPINLOCK(nfs4_deviceid_lock);
	44
	45	void
	46	nfs4_print_deviceid(const struct nfs4_deviceid *id)
	47	{
	48	u32 p = (u32 )id;
	49
	50	dprintk("%s: device id= [%x%x%x%x]\n", __func__,
	51	p[0], p[1], p[2], p[3]);
	52	}
	53	EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
	54
	55	static inline u32
	56	nfs4_deviceid_hash(const struct nfs4_deviceid *id)
	57	{
	58	unsigned char cptr = (unsigned char )id->data;
	59	unsigned int nbytes = NFS4_DEVICEID4_SIZE;
	60	u32 x = 0;
	61
	62	while (nbytes--) {
	63	x *= 37;
	64	x += *cptr++;
65	}
66	return x & NFS4_DEVICE_ID_HASH_MASK;
67	}
68
1be5683b	69	static struct nfs4_deviceid_node *
35c8bb54 BH	70	_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	71	const struct nfs_client clp, const struct nfs4_deviceid id,
1be5683b ME	72	long hash)
	73	{
	74	struct nfs4_deviceid_node *d;
	75	struct hlist_node *n;
	76
	77	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
35c8bb54 BH	78	if (d->ld == ld && d->nfs_client == clp &&
35c8bb54 BH	79	!memcmp(&d->deviceid, id, sizeof(*id))) {
1be5683b ME	80	if (atomic_read(&d->ref))
	81	return d;
	82	else
	83	continue;
	84	}
	85	return NULL;
	86	}
	87
a1eaecbc BH	88	/*
	89	* Lookup a deviceid in cache and get a reference count on it if found
	90	*
	91	* @clp nfs_client associated with deviceid
	92	* @id deviceid to look up
	93	*/
1be5683b	94	struct nfs4_deviceid_node *
35c8bb54 BH	95	_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	96	const struct nfs_client clp, const struct nfs4_deviceid id,
1be5683b ME	97	long hash)
	98	{
	99	struct nfs4_deviceid_node *d;
	100
	101	rcu_read_lock();
35c8bb54	102	d = _lookup_deviceid(ld, clp, id, hash);
1be5683b ME	103	if (d && !atomic_inc_not_zero(&d->ref))
	104	d = NULL;
	105	rcu_read_unlock();
	106	return d;
	107	}
	108
a1eaecbc	109	struct nfs4_deviceid_node *
35c8bb54 BH	110	nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	111	const struct nfs_client clp, const struct nfs4_deviceid id)
1be5683b	112	{
35c8bb54	113	return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
1be5683b ME	114	}
	115	EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
	116
	117	/*
	118	* Unhash and put deviceid
	119	*
	120	* @clp nfs_client associated with deviceid
	121	* @id the deviceid to unhash
	122	*
	123	* @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
	124	*/
	125	struct nfs4_deviceid_node *
35c8bb54 BH	126	nfs4_unhash_put_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	127	const struct nfs_client clp, const struct nfs4_deviceid id)
a1eaecbc BH	128	{
a1eaecbc BH	129	struct nfs4_deviceid_node *d;
a1eaecbc	130
1be5683b	131	spin_lock(&nfs4_deviceid_lock);
a1eaecbc	132	rcu_read_lock();
35c8bb54	133	d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
a1eaecbc	134	rcu_read_unlock();
1be5683b ME	135	if (!d) {
	136	spin_unlock(&nfs4_deviceid_lock);
	137	return NULL;
	138	}
	139	hlist_del_init_rcu(&d->node);
	140	spin_unlock(&nfs4_deviceid_lock);
	141	synchronize_rcu();
	142
	143	/* balance the initial ref set in pnfs_insert_deviceid */
	144	if (atomic_dec_and_test(&d->ref))
	145	return d;
	146
a1eaecbc BH	147	return NULL;
a1eaecbc BH	148	}
1be5683b ME	149	EXPORT_SYMBOL_GPL(nfs4_unhash_put_deviceid);
	150
	151	/*
	152	* Delete a deviceid from cache
	153	*
	154	* @clp struct nfs_client qualifying the deviceid
	155	* @id deviceid to delete
	156	*/
	157	void
35c8bb54 BH	158	nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	159	const struct nfs_client clp, const struct nfs4_deviceid id)
1be5683b ME	160	{
	161	struct nfs4_deviceid_node *d;
	162
35c8bb54	163	d = nfs4_unhash_put_deviceid(ld, clp, id);
1be5683b ME	164	if (!d)
	165	return;
	166	d->ld->free_deviceid_node(d);
	167	}
	168	EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
a1eaecbc BH	169
	170	void
	171	nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
1775bc34	172	const struct pnfs_layoutdriver_type *ld,
a1eaecbc BH	173	const struct nfs_client *nfs_client,
	174	const struct nfs4_deviceid *id)
	175	{
1775bc34	176	INIT_HLIST_NODE(&d->node);
9e3bd4e2	177	INIT_HLIST_NODE(&d->tmpnode);
1775bc34	178	d->ld = ld;
a1eaecbc BH	179	d->nfs_client = nfs_client;
a1eaecbc BH	180	d->deviceid = *id;
1775bc34	181	atomic_set(&d->ref, 1);
a1eaecbc BH	182	}
	183	EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
	184
	185	/*
	186	* Uniquely initialize and insert a deviceid node into cache
	187	*
	188	* @new new deviceid node
1775bc34 BH	189	* Note that the caller must set up the following members:
	190	* new->ld
	191	* new->nfs_client
	192	* new->deviceid
a1eaecbc BH	193	*
	194	* @ret the inserted node, if none found, otherwise, the found entry.
	195	*/
	196	struct nfs4_deviceid_node *
	197	nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
	198	{
	199	struct nfs4_deviceid_node *d;
	200	long hash;
	201
	202	spin_lock(&nfs4_deviceid_lock);
1be5683b	203	hash = nfs4_deviceid_hash(&new->deviceid);
35c8bb54	204	d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash);
a1eaecbc BH	205	if (d) {
	206	spin_unlock(&nfs4_deviceid_lock);
	207	return d;
	208	}
	209
a1eaecbc BH	210	hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
a1eaecbc BH	211	spin_unlock(&nfs4_deviceid_lock);
1d92a08d	212	atomic_inc(&new->ref);
a1eaecbc BH	213
	214	return new;
	215	}
	216	EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
	217
	218	/*
	219	* Dereference a deviceid node and delete it when its reference count drops
	220	* to zero.
	221	*
	222	* @d deviceid node to put
	223	*
	224	* @ret true iff the node was deleted
	225	*/
	226	bool
	227	nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
	228	{
	229	if (!atomic_dec_and_lock(&d->ref, &nfs4_deviceid_lock))
	230	return false;
	231	hlist_del_init_rcu(&d->node);
	232	spin_unlock(&nfs4_deviceid_lock);
	233	synchronize_rcu();
1775bc34	234	d->ld->free_deviceid_node(d);
a1eaecbc BH	235	return true;
	236	}
	237	EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
1775bc34 BH	238
	239	static void
	240	_deviceid_purge_client(const struct nfs_client *clp, long hash)
	241	{
	242	struct nfs4_deviceid_node *d;
9e3bd4e2	243	struct hlist_node *n;
1775bc34 BH	244	HLIST_HEAD(tmp);
1775bc34 BH	245
9e3bd4e2	246	spin_lock(&nfs4_deviceid_lock);
1775bc34 BH	247	rcu_read_lock();
	248	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
	249	if (d->nfs_client == clp && atomic_read(&d->ref)) {
	250	hlist_del_init_rcu(&d->node);
9e3bd4e2	251	hlist_add_head(&d->tmpnode, &tmp);
1775bc34 BH	252	}
1775bc34 BH	253	rcu_read_unlock();
9e3bd4e2	254	spin_unlock(&nfs4_deviceid_lock);
1775bc34 BH	255
	256	if (hlist_empty(&tmp))
	257	return;
	258
	259	synchronize_rcu();
9e3bd4e2 WAA	260	while (!hlist_empty(&tmp)) {
	261	d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
	262	hlist_del(&d->tmpnode);
1775bc34 BH	263	if (atomic_dec_and_test(&d->ref))
1775bc34 BH	264	d->ld->free_deviceid_node(d);
9e3bd4e2	265	}
1775bc34 BH	266	}
	267
	268	void
	269	nfs4_deviceid_purge_client(const struct nfs_client *clp)
	270	{
	271	long h;
	272
9e3bd4e2 WAA	273	if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
9e3bd4e2 WAA	274	return;
1775bc34 BH	275	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
1775bc34 BH	276	_deviceid_purge_client(clp, h);
1775bc34	277	}