[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 <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;
	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);

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;
	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
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;
	80	struct hlist_node *n;
	81
	82	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
35c8bb54 BH	83	if (d->ld == ld && d->nfs_client == clp &&
35c8bb54 BH	84	!memcmp(&d->deviceid, id, sizeof(*id))) {
1be5683b ME	85	if (atomic_read(&d->ref))
	86	return d;
	87	else
	88	continue;
	89	}
	90	return NULL;
	91	}
	92
a1eaecbc BH	93	/*
	94	* Lookup a deviceid in cache and get a reference count on it if found
	95	*
	96	* @clp nfs_client associated with deviceid
	97	* @id deviceid to look up
	98	*/
17280175	99	static struct nfs4_deviceid_node *
35c8bb54 BH	100	_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	101	const struct nfs_client clp, const struct nfs4_deviceid id,
1be5683b ME	102	long hash)
	103	{
	104	struct nfs4_deviceid_node *d;
	105
	106	rcu_read_lock();
35c8bb54	107	d = _lookup_deviceid(ld, clp, id, hash);
47cb498e TM	108	if (d != NULL)
47cb498e TM	109	atomic_inc(&d->ref);
1be5683b ME	110	rcu_read_unlock();
	111	return d;
	112	}
	113
a1eaecbc	114	struct nfs4_deviceid_node *
35c8bb54 BH	115	nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54 BH	116	const struct nfs_client clp, const struct nfs4_deviceid id)
1be5683b	117	{
35c8bb54	118	return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
1be5683b ME	119	}
	120	EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
	121
	122	/*
47cb498e	123	* Remove a deviceid from cache
1be5683b ME	124	*
	125	* @clp nfs_client associated with deviceid
	126	* @id the deviceid to unhash
	127	*
	128	* @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
	129	*/
47cb498e TM	130	void
47cb498e TM	131	nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
35c8bb54	132	const struct nfs_client clp, const struct nfs4_deviceid id)
a1eaecbc BH	133	{
a1eaecbc BH	134	struct nfs4_deviceid_node *d;
a1eaecbc	135
1be5683b	136	spin_lock(&nfs4_deviceid_lock);
a1eaecbc	137	rcu_read_lock();
35c8bb54	138	d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
a1eaecbc	139	rcu_read_unlock();
1be5683b ME	140	if (!d) {
1be5683b ME	141	spin_unlock(&nfs4_deviceid_lock);
47cb498e	142	return;
1be5683b ME	143	}
	144	hlist_del_init_rcu(&d->node);
	145	spin_unlock(&nfs4_deviceid_lock);
	146	synchronize_rcu();
	147
	148	/* balance the initial ref set in pnfs_insert_deviceid */
	149	if (atomic_dec_and_test(&d->ref))
47cb498e	150	d->ld->free_deviceid_node(d);
1be5683b ME	151	}
1be5683b ME	152	EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
a1eaecbc BH	153
	154	void
	155	nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
1775bc34	156	const struct pnfs_layoutdriver_type *ld,
a1eaecbc BH	157	const struct nfs_client *nfs_client,
	158	const struct nfs4_deviceid *id)
	159	{
1775bc34	160	INIT_HLIST_NODE(&d->node);
9e3bd4e2	161	INIT_HLIST_NODE(&d->tmpnode);
1775bc34	162	d->ld = ld;
a1eaecbc	163	d->nfs_client = nfs_client;
c47abcf8	164	d->flags = 0;
a1eaecbc	165	d->deviceid = *id;
1775bc34	166	atomic_set(&d->ref, 1);
a1eaecbc BH	167	}
	168	EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
	169
	170	/*
	171	* Uniquely initialize and insert a deviceid node into cache
	172	*
	173	* @new new deviceid node
1775bc34 BH	174	* Note that the caller must set up the following members:
	175	* new->ld
	176	* new->nfs_client
	177	* new->deviceid
a1eaecbc BH	178	*
	179	* @ret the inserted node, if none found, otherwise, the found entry.
	180	*/
	181	struct nfs4_deviceid_node *
	182	nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
	183	{
	184	struct nfs4_deviceid_node *d;
	185	long hash;
	186
	187	spin_lock(&nfs4_deviceid_lock);
1be5683b	188	hash = nfs4_deviceid_hash(&new->deviceid);
35c8bb54	189	d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash);
a1eaecbc BH	190	if (d) {
	191	spin_unlock(&nfs4_deviceid_lock);
	192	return d;
	193	}
	194
a1eaecbc BH	195	hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
a1eaecbc BH	196	spin_unlock(&nfs4_deviceid_lock);
1d92a08d	197	atomic_inc(&new->ref);
a1eaecbc BH	198
	199	return new;
	200	}
	201	EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
	202
	203	/*
	204	* Dereference a deviceid node and delete it when its reference count drops
	205	* to zero.
	206	*
	207	* @d deviceid node to put
	208	*
47cb498e TM	209	* return true iff the node was deleted
	210	* Note that since the test for d->ref == 0 is sufficient to establish
	211	* that the node is no longer hashed in the global device id cache.
a1eaecbc BH	212	*/
	213	bool
	214	nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
	215	{
47cb498e	216	if (!atomic_dec_and_test(&d->ref))
a1eaecbc	217	return false;
1775bc34	218	d->ld->free_deviceid_node(d);
a1eaecbc BH	219	return true;
	220	}
	221	EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
1775bc34	222
1dfed273 TM	223	void
	224	nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
	225	{
	226	node->timestamp_unavailable = jiffies;
	227	set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
	228	}
	229	EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
	230
	231	bool
	232	nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
	233	{
	234	if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
	235	unsigned long start, end;
	236
	237	end = jiffies;
	238	start = end - PNFS_DEVICE_RETRY_TIMEOUT;
	239	if (time_in_range(node->timestamp_unavailable, start, end))
	240	return true;
	241	clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
	242	}
	243	return false;
	244	}
	245	EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
	246
1775bc34 BH	247	static void
	248	_deviceid_purge_client(const struct nfs_client *clp, long hash)
	249	{
	250	struct nfs4_deviceid_node *d;
9e3bd4e2	251	struct hlist_node *n;
1775bc34 BH	252	HLIST_HEAD(tmp);
1775bc34 BH	253
9e3bd4e2	254	spin_lock(&nfs4_deviceid_lock);
1775bc34 BH	255	rcu_read_lock();
	256	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
	257	if (d->nfs_client == clp && atomic_read(&d->ref)) {
	258	hlist_del_init_rcu(&d->node);
9e3bd4e2	259	hlist_add_head(&d->tmpnode, &tmp);
1775bc34 BH	260	}
1775bc34 BH	261	rcu_read_unlock();
9e3bd4e2	262	spin_unlock(&nfs4_deviceid_lock);
1775bc34 BH	263
	264	if (hlist_empty(&tmp))
	265	return;
	266
	267	synchronize_rcu();
9e3bd4e2 WAA	268	while (!hlist_empty(&tmp)) {
	269	d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
	270	hlist_del(&d->tmpnode);
1775bc34 BH	271	if (atomic_dec_and_test(&d->ref))
1775bc34 BH	272	d->ld->free_deviceid_node(d);
9e3bd4e2	273	}
1775bc34 BH	274	}
	275
	276	void
	277	nfs4_deviceid_purge_client(const struct nfs_client *clp)
	278	{
	279	long h;
	280
9e3bd4e2 WAA	281	if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
9e3bd4e2 WAA	282	return;
1775bc34 BH	283	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
1775bc34 BH	284	_deviceid_purge_client(clp, h);
1775bc34	285	}
c47abcf8 AA	286
	287	/*
	288	* Stop use of all deviceids associated with an nfs_client
	289	*/
	290	void
	291	nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
	292	{
	293	struct nfs4_deviceid_node *d;
	294	struct hlist_node *n;
	295	int i;
	296
	297	rcu_read_lock();
	298	for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
	299	hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[i], node)
	300	if (d->nfs_client == clp)
	301	set_bit(NFS_DEVICEID_INVALID, &d->flags);
	302	}
	303	rcu_read_unlock();
	304	}
1dfed273	305