[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 <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)

#define PNFS_DEVICE_RETRY_TIMEOUT (120*HZ)

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;

	hlist_for_each_entry_rcu(d, &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);

void
nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
{
	node->timestamp_unavailable = jiffies;
	set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
}
EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);

bool
nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
{
	if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
		unsigned long start, end;

		end = jiffies;
		start = end - PNFS_DEVICE_RETRY_TIMEOUT;
		if (time_in_range(node->timestamp_unavailable, start, end))
			return true;
		clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
	}
	return false;
}
EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);

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

	spin_lock(&nfs4_deviceid_lock);
	rcu_read_lock();
	hlist_for_each_entry_rcu(d, &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;
	int i;

	rcu_read_lock();
	for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
		hlist_for_each_entry_rcu(d, &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
1dfed273 TM	43	#define PNFS_DEVICE_RETRY_TIMEOUT (120*HZ)
1dfed273 TM	44
a1eaecbc BH	45	static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
	46	static DEFINE_SPINLOCK(nfs4_deviceid_lock);
	47
6f00866d	48	#ifdef NFS_DEBUG
a1eaecbc BH	49	void
	50	nfs4_print_deviceid(const struct nfs4_deviceid *id)
	51	{
	52	u32 p = (u32 )id;
	53
	54	dprintk("%s: device id= [%x%x%x%x]\n", __func__,
	55	p[0], p[1], p[2], p[3]);
	56	}
	57	EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
6f00866d	58	#endif
a1eaecbc BH	59
	60	static inline u32
	61	nfs4_deviceid_hash(const struct nfs4_deviceid *id)
	62	{
	63	unsigned char cptr = (unsigned char )id->data;
	64	unsigned int nbytes = NFS4_DEVICEID4_SIZE;
	65	u32 x = 0;
	66
	67	while (nbytes--) {
	68	x *= 37;
	69	x += *cptr++;
	70	}
	71	return x & NFS4_DEVICE_ID_HASH_MASK;
	72	}
	73
1be5683b	74	static struct nfs4_deviceid_node *
35c8bb54 BH	75	_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	76	const struct nfs_client clp, const struct nfs4_deviceid id,
1be5683b ME	77	long hash)
	78	{
	79	struct nfs4_deviceid_node *d;
1be5683b	80
b67bfe0d	81	hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
35c8bb54 BH	82	if (d->ld == ld && d->nfs_client == clp &&
35c8bb54 BH	83	!memcmp(&d->deviceid, id, sizeof(*id))) {
1be5683b ME	84	if (atomic_read(&d->ref))
	85	return d;
	86	else
	87	continue;
	88	}
	89	return NULL;
	90	}
	91
a1eaecbc BH	92	/*
	93	* Lookup a deviceid in cache and get a reference count on it if found
	94	*
	95	* @clp nfs_client associated with deviceid
	96	* @id deviceid to look up
	97	*/
17280175	98	static struct nfs4_deviceid_node *
35c8bb54 BH	99	_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	100	const struct nfs_client clp, const struct nfs4_deviceid id,
1be5683b ME	101	long hash)
	102	{
	103	struct nfs4_deviceid_node *d;
	104
	105	rcu_read_lock();
35c8bb54	106	d = _lookup_deviceid(ld, clp, id, hash);
47cb498e TM	107	if (d != NULL)
47cb498e TM	108	atomic_inc(&d->ref);
1be5683b ME	109	rcu_read_unlock();
	110	return d;
	111	}
	112
a1eaecbc	113	struct nfs4_deviceid_node *
35c8bb54 BH	114	nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	115	const struct nfs_client clp, const struct nfs4_deviceid id)
1be5683b	116	{
35c8bb54	117	return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
1be5683b ME	118	}
	119	EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
	120
	121	/*
47cb498e	122	* Remove a deviceid from cache
1be5683b ME	123	*
	124	* @clp nfs_client associated with deviceid
	125	* @id the deviceid to unhash
	126	*
	127	* @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
	128	*/
47cb498e TM	129	void
47cb498e TM	130	nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54	131	const struct nfs_client clp, const struct nfs4_deviceid id)
a1eaecbc BH	132	{
a1eaecbc BH	133	struct nfs4_deviceid_node *d;
a1eaecbc	134
1be5683b	135	spin_lock(&nfs4_deviceid_lock);
a1eaecbc	136	rcu_read_lock();
35c8bb54	137	d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
a1eaecbc	138	rcu_read_unlock();
1be5683b ME	139	if (!d) {
1be5683b ME	140	spin_unlock(&nfs4_deviceid_lock);
47cb498e	141	return;
1be5683b ME	142	}
	143	hlist_del_init_rcu(&d->node);
	144	spin_unlock(&nfs4_deviceid_lock);
	145	synchronize_rcu();
	146
	147	/* balance the initial ref set in pnfs_insert_deviceid */
	148	if (atomic_dec_and_test(&d->ref))
47cb498e	149	d->ld->free_deviceid_node(d);
1be5683b ME	150	}
1be5683b ME	151	EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
a1eaecbc BH	152
	153	void
	154	nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
1775bc34	155	const struct pnfs_layoutdriver_type *ld,
a1eaecbc BH	156	const struct nfs_client *nfs_client,
	157	const struct nfs4_deviceid *id)
	158	{
1775bc34	159	INIT_HLIST_NODE(&d->node);
9e3bd4e2	160	INIT_HLIST_NODE(&d->tmpnode);
1775bc34	161	d->ld = ld;
a1eaecbc	162	d->nfs_client = nfs_client;
c47abcf8	163	d->flags = 0;
a1eaecbc	164	d->deviceid = *id;
1775bc34	165	atomic_set(&d->ref, 1);
a1eaecbc BH	166	}
	167	EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
	168
	169	/*
	170	* Uniquely initialize and insert a deviceid node into cache
	171	*
	172	* @new new deviceid node
1775bc34 BH	173	* Note that the caller must set up the following members:
	174	* new->ld
	175	* new->nfs_client
	176	* new->deviceid
a1eaecbc BH	177	*
	178	* @ret the inserted node, if none found, otherwise, the found entry.
	179	*/
	180	struct nfs4_deviceid_node *
	181	nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
	182	{
	183	struct nfs4_deviceid_node *d;
	184	long hash;
	185
	186	spin_lock(&nfs4_deviceid_lock);
1be5683b	187	hash = nfs4_deviceid_hash(&new->deviceid);
35c8bb54	188	d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash);
a1eaecbc BH	189	if (d) {
	190	spin_unlock(&nfs4_deviceid_lock);
	191	return d;
	192	}
	193
a1eaecbc BH	194	hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
a1eaecbc BH	195	spin_unlock(&nfs4_deviceid_lock);
1d92a08d	196	atomic_inc(&new->ref);
a1eaecbc BH	197
	198	return new;
	199	}
	200	EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
	201
	202	/*
	203	* Dereference a deviceid node and delete it when its reference count drops
	204	* to zero.
	205	*
	206	* @d deviceid node to put
	207	*
47cb498e TM	208	* return true iff the node was deleted
	209	* Note that since the test for d->ref == 0 is sufficient to establish
	210	* that the node is no longer hashed in the global device id cache.
a1eaecbc BH	211	*/
	212	bool
	213	nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
	214	{
47cb498e	215	if (!atomic_dec_and_test(&d->ref))
a1eaecbc	216	return false;
1775bc34	217	d->ld->free_deviceid_node(d);
a1eaecbc BH	218	return true;
	219	}
	220	EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
1775bc34	221
1dfed273 TM	222	void
	223	nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
	224	{
	225	node->timestamp_unavailable = jiffies;
	226	set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
	227	}
	228	EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
	229
	230	bool
	231	nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
	232	{
	233	if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
	234	unsigned long start, end;
	235
	236	end = jiffies;
	237	start = end - PNFS_DEVICE_RETRY_TIMEOUT;
	238	if (time_in_range(node->timestamp_unavailable, start, end))
	239	return true;
	240	clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
	241	}
	242	return false;
	243	}
	244	EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
	245
1775bc34 BH	246	static void
	247	_deviceid_purge_client(const struct nfs_client *clp, long hash)
	248	{
	249	struct nfs4_deviceid_node *d;
1775bc34 BH	250	HLIST_HEAD(tmp);
1775bc34 BH	251
9e3bd4e2	252	spin_lock(&nfs4_deviceid_lock);
1775bc34	253	rcu_read_lock();
b67bfe0d	254	hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
1775bc34 BH	255	if (d->nfs_client == clp && atomic_read(&d->ref)) {
1775bc34 BH	256	hlist_del_init_rcu(&d->node);
9e3bd4e2	257	hlist_add_head(&d->tmpnode, &tmp);
1775bc34 BH	258	}
1775bc34 BH	259	rcu_read_unlock();
9e3bd4e2	260	spin_unlock(&nfs4_deviceid_lock);
1775bc34 BH	261
	262	if (hlist_empty(&tmp))
	263	return;
	264
	265	synchronize_rcu();
9e3bd4e2 WAA	266	while (!hlist_empty(&tmp)) {
	267	d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
	268	hlist_del(&d->tmpnode);
1775bc34 BH	269	if (atomic_dec_and_test(&d->ref))
1775bc34 BH	270	d->ld->free_deviceid_node(d);
9e3bd4e2	271	}
1775bc34 BH	272	}
	273
	274	void
	275	nfs4_deviceid_purge_client(const struct nfs_client *clp)
	276	{
	277	long h;
	278
9e3bd4e2 WAA	279	if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
9e3bd4e2 WAA	280	return;
1775bc34 BH	281	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
1775bc34 BH	282	_deviceid_purge_client(clp, h);
1775bc34	283	}
c47abcf8 AA	284
	285	/*
	286	* Stop use of all deviceids associated with an nfs_client
	287	*/
	288	void
	289	nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
	290	{
	291	struct nfs4_deviceid_node *d;
c47abcf8 AA	292	int i;
	293
	294	rcu_read_lock();
	295	for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
b67bfe0d	296	hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
c47abcf8 AA	297	if (d->nfs_client == clp)
	298	set_bit(NFS_DEVICEID_INVALID, &d->flags);
	299	}
	300	rcu_read_unlock();
	301	}
1dfed273	302