[mirror_ubuntu-bionic-kernel.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 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->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 nfs_client *clp, const struct nfs4_deviceid *id,
		   long hash)
{
	struct nfs4_deviceid_node *d;

	rcu_read_lock();
	d = _lookup_deviceid(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 nfs_client *clp, const struct nfs4_deviceid *id)
{
	return _find_get_deviceid(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 nfs_client *clp, const struct nfs4_deviceid *id)
{
	struct nfs4_deviceid_node *d;

	spin_lock(&nfs4_deviceid_lock);
	rcu_read_lock();
	d = _lookup_deviceid(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 nfs_client *clp, const struct nfs4_deviceid *id)
{
	struct nfs4_deviceid_node *d;

	d = nfs4_unhash_put_deviceid(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);
	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->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);

	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, *next;
	HLIST_HEAD(tmp);

	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->node, &tmp);
		}
	rcu_read_unlock();

	if (hlist_empty(&tmp))
		return;

	synchronize_rcu();
	hlist_for_each_entry_safe(d, n, next, &tmp, node)
		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;

	spin_lock(&nfs4_deviceid_lock);
	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
		_deviceid_purge_client(clp, h);
	spin_unlock(&nfs4_deviceid_lock);
}
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 ME	69	static struct nfs4_deviceid_node *
	70	_lookup_deviceid(const struct nfs_client clp, const struct nfs4_deviceid id,
	71	long hash)
	72	{
	73	struct nfs4_deviceid_node *d;
	74	struct hlist_node *n;
	75
	76	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
	77	if (d->nfs_client == clp && !memcmp(&d->deviceid, id, sizeof(*id))) {
	78	if (atomic_read(&d->ref))
	79	return d;
	80	else
	81	continue;
	82	}
	83	return NULL;
	84	}
	85
a1eaecbc BH	86	/*
	87	* Lookup a deviceid in cache and get a reference count on it if found
	88	*
	89	* @clp nfs_client associated with deviceid
	90	* @id deviceid to look up
	91	*/
1be5683b ME	92	struct nfs4_deviceid_node *
	93	_find_get_deviceid(const struct nfs_client clp, const struct nfs4_deviceid id,
	94	long hash)
	95	{
	96	struct nfs4_deviceid_node *d;
	97
	98	rcu_read_lock();
	99	d = _lookup_deviceid(clp, id, hash);
	100	if (d && !atomic_inc_not_zero(&d->ref))
	101	d = NULL;
	102	rcu_read_unlock();
	103	return d;
	104	}
	105
a1eaecbc BH	106	struct nfs4_deviceid_node *
a1eaecbc BH	107	nfs4_find_get_deviceid(const struct nfs_client clp, const struct nfs4_deviceid id)
1be5683b ME	108	{
	109	return _find_get_deviceid(clp, id, nfs4_deviceid_hash(id));
	110	}
	111	EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
	112
	113	/*
	114	* Unhash and put deviceid
	115	*
	116	* @clp nfs_client associated with deviceid
	117	* @id the deviceid to unhash
	118	*
	119	* @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
	120	*/
	121	struct nfs4_deviceid_node *
	122	nfs4_unhash_put_deviceid(const struct nfs_client clp, const struct nfs4_deviceid id)
a1eaecbc BH	123	{
a1eaecbc BH	124	struct nfs4_deviceid_node *d;
a1eaecbc	125
1be5683b	126	spin_lock(&nfs4_deviceid_lock);
a1eaecbc	127	rcu_read_lock();
1be5683b	128	d = _lookup_deviceid(clp, id, nfs4_deviceid_hash(id));
a1eaecbc	129	rcu_read_unlock();
1be5683b ME	130	if (!d) {
	131	spin_unlock(&nfs4_deviceid_lock);
	132	return NULL;
	133	}
	134	hlist_del_init_rcu(&d->node);
	135	spin_unlock(&nfs4_deviceid_lock);
	136	synchronize_rcu();
	137
	138	/* balance the initial ref set in pnfs_insert_deviceid */
	139	if (atomic_dec_and_test(&d->ref))
	140	return d;
	141
a1eaecbc BH	142	return NULL;
a1eaecbc BH	143	}
1be5683b ME	144	EXPORT_SYMBOL_GPL(nfs4_unhash_put_deviceid);
	145
	146	/*
	147	* Delete a deviceid from cache
	148	*
	149	* @clp struct nfs_client qualifying the deviceid
	150	* @id deviceid to delete
	151	*/
	152	void
	153	nfs4_delete_deviceid(const struct nfs_client clp, const struct nfs4_deviceid id)
	154	{
	155	struct nfs4_deviceid_node *d;
	156
	157	d = nfs4_unhash_put_deviceid(clp, id);
	158	if (!d)
	159	return;
	160	d->ld->free_deviceid_node(d);
	161	}
	162	EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
a1eaecbc BH	163
	164	void
	165	nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
1775bc34	166	const struct pnfs_layoutdriver_type *ld,
a1eaecbc BH	167	const struct nfs_client *nfs_client,
	168	const struct nfs4_deviceid *id)
	169	{
1775bc34 BH	170	INIT_HLIST_NODE(&d->node);
1775bc34 BH	171	d->ld = ld;
a1eaecbc BH	172	d->nfs_client = nfs_client;
a1eaecbc BH	173	d->deviceid = *id;
1775bc34	174	atomic_set(&d->ref, 1);
a1eaecbc BH	175	}
	176	EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
	177
	178	/*
	179	* Uniquely initialize and insert a deviceid node into cache
	180	*
	181	* @new new deviceid node
1775bc34 BH	182	* Note that the caller must set up the following members:
	183	* new->ld
	184	* new->nfs_client
	185	* new->deviceid
a1eaecbc BH	186	*
	187	* @ret the inserted node, if none found, otherwise, the found entry.
	188	*/
	189	struct nfs4_deviceid_node *
	190	nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
	191	{
	192	struct nfs4_deviceid_node *d;
	193	long hash;
	194
	195	spin_lock(&nfs4_deviceid_lock);
1be5683b ME	196	hash = nfs4_deviceid_hash(&new->deviceid);
1be5683b ME	197	d = _find_get_deviceid(new->nfs_client, &new->deviceid, hash);
a1eaecbc BH	198	if (d) {
	199	spin_unlock(&nfs4_deviceid_lock);
	200	return d;
	201	}
	202
a1eaecbc BH	203	hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
	204	spin_unlock(&nfs4_deviceid_lock);
	205
	206	return new;
	207	}
	208	EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
	209
	210	/*
	211	* Dereference a deviceid node and delete it when its reference count drops
	212	* to zero.
	213	*
	214	* @d deviceid node to put
	215	*
	216	* @ret true iff the node was deleted
	217	*/
	218	bool
	219	nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
	220	{
	221	if (!atomic_dec_and_lock(&d->ref, &nfs4_deviceid_lock))
	222	return false;
	223	hlist_del_init_rcu(&d->node);
	224	spin_unlock(&nfs4_deviceid_lock);
	225	synchronize_rcu();
1775bc34	226	d->ld->free_deviceid_node(d);
a1eaecbc BH	227	return true;
	228	}
	229	EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
1775bc34 BH	230
	231	static void
	232	_deviceid_purge_client(const struct nfs_client *clp, long hash)
	233	{
	234	struct nfs4_deviceid_node *d;
	235	struct hlist_node n, next;
	236	HLIST_HEAD(tmp);
	237
	238	rcu_read_lock();
	239	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
	240	if (d->nfs_client == clp && atomic_read(&d->ref)) {
	241	hlist_del_init_rcu(&d->node);
	242	hlist_add_head(&d->node, &tmp);
	243	}
	244	rcu_read_unlock();
	245
	246	if (hlist_empty(&tmp))
	247	return;
	248
	249	synchronize_rcu();
	250	hlist_for_each_entry_safe(d, n, next, &tmp, node)
	251	if (atomic_dec_and_test(&d->ref))
	252	d->ld->free_deviceid_node(d);
	253	}
	254
	255	void
	256	nfs4_deviceid_purge_client(const struct nfs_client *clp)
	257	{
	258	long h;
	259
	260	spin_lock(&nfs4_deviceid_lock);
	261	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
	262	_deviceid_purge_client(clp, h);
	263	spin_unlock(&nfs4_deviceid_lock);
	264	}