[deliverable/linux.git] / drivers / staging / lustre / lustre / ldlm / ldlm_extent.c

/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2010, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/ldlm/ldlm_extent.c
 *
 * Author: Peter Braam <braam@clusterfs.com>
 * Author: Phil Schwan <phil@clusterfs.com>
 */

/**
 * This file contains implementation of EXTENT lock type
 *
 * EXTENT lock type is for locking a contiguous range of values, represented
 * by 64-bit starting and ending offsets (inclusive). There are several extent
 * lock modes, some of which may be mutually incompatible. Extent locks are
 * considered incompatible if their modes are incompatible and their extents
 * intersect.  See the lock mode compatibility matrix in lustre_dlm.h.
 */

#define DEBUG_SUBSYSTEM S_LDLM
#include "../../include/linux/libcfs/libcfs.h"

#include <lustre_dlm.h>
#include <obd_support.h>
#include <obd.h>
#include <obd_class.h>
#include <lustre_lib.h>

#include "ldlm_internal.h"


/* When a lock is cancelled by a client, the KMS may undergo change if this
 * is the "highest lock".  This function returns the new KMS value.
 * Caller must hold lr_lock already.
 *
 * NB: A lock on [x,y] protects a KMS of up to y + 1 bytes! */
__u64 ldlm_extent_shift_kms(struct ldlm_lock *lock, __u64 old_kms)
{
	struct ldlm_resource *res = lock->l_resource;
	struct list_head *tmp;
	struct ldlm_lock *lck;
	__u64 kms = 0;

	/* don't let another thread in ldlm_extent_shift_kms race in
	 * just after we finish and take our lock into account in its
	 * calculation of the kms */
	lock->l_flags |= LDLM_FL_KMS_IGNORE;

	list_for_each(tmp, &res->lr_granted) {
		lck = list_entry(tmp, struct ldlm_lock, l_res_link);

		if (lck->l_flags & LDLM_FL_KMS_IGNORE)
			continue;

		if (lck->l_policy_data.l_extent.end >= old_kms)
			return old_kms;

		/* This extent _has_ to be smaller than old_kms (checked above)
		 * so kms can only ever be smaller or the same as old_kms. */
		if (lck->l_policy_data.l_extent.end + 1 > kms)
			kms = lck->l_policy_data.l_extent.end + 1;
	}
	LASSERTF(kms <= old_kms, "kms "LPU64" old_kms "LPU64"\n", kms, old_kms);

	return kms;
}
EXPORT_SYMBOL(ldlm_extent_shift_kms);

struct kmem_cache *ldlm_interval_slab;
struct ldlm_interval *ldlm_interval_alloc(struct ldlm_lock *lock)
{
	struct ldlm_interval *node;

	LASSERT(lock->l_resource->lr_type == LDLM_EXTENT);
	OBD_SLAB_ALLOC_PTR_GFP(node, ldlm_interval_slab, GFP_NOFS);
	if (node == NULL)
		return NULL;

	INIT_LIST_HEAD(&node->li_group);
	ldlm_interval_attach(node, lock);
	return node;
}

void ldlm_interval_free(struct ldlm_interval *node)
{
	if (node) {
		LASSERT(list_empty(&node->li_group));
		LASSERT(!interval_is_intree(&node->li_node));
		OBD_SLAB_FREE(node, ldlm_interval_slab, sizeof(*node));
	}
}

/* interval tree, for LDLM_EXTENT. */
void ldlm_interval_attach(struct ldlm_interval *n,
			  struct ldlm_lock *l)
{
	LASSERT(l->l_tree_node == NULL);
	LASSERT(l->l_resource->lr_type == LDLM_EXTENT);

	list_add_tail(&l->l_sl_policy, &n->li_group);
	l->l_tree_node = n;
}

struct ldlm_interval *ldlm_interval_detach(struct ldlm_lock *l)
{
	struct ldlm_interval *n = l->l_tree_node;

	if (n == NULL)
		return NULL;

	LASSERT(!list_empty(&n->li_group));
	l->l_tree_node = NULL;
	list_del_init(&l->l_sl_policy);

	return list_empty(&n->li_group) ? n : NULL;
}

static inline int lock_mode_to_index(ldlm_mode_t mode)
{
	int index;

	LASSERT(mode != 0);
	LASSERT(IS_PO2(mode));
	for (index = -1; mode; index++, mode >>= 1) ;
	LASSERT(index < LCK_MODE_NUM);
	return index;
}

/** Add newly granted lock into interval tree for the resource. */
void ldlm_extent_add_lock(struct ldlm_resource *res,
			  struct ldlm_lock *lock)
{
	struct interval_node *found, **root;
	struct ldlm_interval *node;
	struct ldlm_extent *extent;
	int idx;

	LASSERT(lock->l_granted_mode == lock->l_req_mode);

	node = lock->l_tree_node;
	LASSERT(node != NULL);
	LASSERT(!interval_is_intree(&node->li_node));

	idx = lock_mode_to_index(lock->l_granted_mode);
	LASSERT(lock->l_granted_mode == 1 << idx);
	LASSERT(lock->l_granted_mode == res->lr_itree[idx].lit_mode);

	/* node extent initialize */
	extent = &lock->l_policy_data.l_extent;
	interval_set(&node->li_node, extent->start, extent->end);

	root = &res->lr_itree[idx].lit_root;
	found = interval_insert(&node->li_node, root);
	if (found) { /* The policy group found. */
		struct ldlm_interval *tmp = ldlm_interval_detach(lock);
		LASSERT(tmp != NULL);
		ldlm_interval_free(tmp);
		ldlm_interval_attach(to_ldlm_interval(found), lock);
	}
	res->lr_itree[idx].lit_size++;

	/* even though we use interval tree to manage the extent lock, we also
	 * add the locks into grant list, for debug purpose, .. */
	ldlm_resource_add_lock(res, &res->lr_granted, lock);
}

/** Remove cancelled lock from resource interval tree. */
void ldlm_extent_unlink_lock(struct ldlm_lock *lock)
{
	struct ldlm_resource *res = lock->l_resource;
	struct ldlm_interval *node = lock->l_tree_node;
	struct ldlm_interval_tree *tree;
	int idx;

	if (!node || !interval_is_intree(&node->li_node)) /* duplicate unlink */
		return;

	idx = lock_mode_to_index(lock->l_granted_mode);
	LASSERT(lock->l_granted_mode == 1 << idx);
	tree = &res->lr_itree[idx];

	LASSERT(tree->lit_root != NULL); /* assure the tree is not null */

	tree->lit_size--;
	node = ldlm_interval_detach(lock);
	if (node) {
		interval_erase(&node->li_node, &tree->lit_root);
		ldlm_interval_free(node);
	}
}

void ldlm_extent_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
				     ldlm_policy_data_t *lpolicy)
{
	memset(lpolicy, 0, sizeof(*lpolicy));
	lpolicy->l_extent.start = wpolicy->l_extent.start;
	lpolicy->l_extent.end = wpolicy->l_extent.end;
	lpolicy->l_extent.gid = wpolicy->l_extent.gid;
}

void ldlm_extent_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
				     ldlm_wire_policy_data_t *wpolicy)
{
	memset(wpolicy, 0, sizeof(*wpolicy));
	wpolicy->l_extent.start = lpolicy->l_extent.start;
	wpolicy->l_extent.end = lpolicy->l_extent.end;
	wpolicy->l_extent.gid = lpolicy->l_extent.gid;
}
Commit	Line	Data
d7e09d03 PT	1	/*
	2	* GPL HEADER START
	3	*
	4	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 only,
	8	* as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* General Public License version 2 for more details (a copy is included
	14	* in the LICENSE file that accompanied this code).
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* version 2 along with this program; If not, see
	18	* http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
	19	*
	20	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	21	* CA 95054 USA or visit www.sun.com if you need additional information or
	22	* have any questions.
	23	*
	24	* GPL HEADER END
	25	*/
	26	/*
	27	* Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
	28	* Use is subject to license terms.
	29	*
	30	* Copyright (c) 2010, 2012, Intel Corporation.
	31	*/
	32	/*
	33	* This file is part of Lustre, http://www.lustre.org/
	34	* Lustre is a trademark of Sun Microsystems, Inc.
	35	*
	36	* lustre/ldlm/ldlm_extent.c
	37	*
	38	* Author: Peter Braam <braam@clusterfs.com>
	39	* Author: Phil Schwan <phil@clusterfs.com>
	40	*/
	41
	42	/**
	43	* This file contains implementation of EXTENT lock type
	44	*
	45	* EXTENT lock type is for locking a contiguous range of values, represented
	46	* by 64-bit starting and ending offsets (inclusive). There are several extent
	47	* lock modes, some of which may be mutually incompatible. Extent locks are
	48	* considered incompatible if their modes are incompatible and their extents
	49	* intersect. See the lock mode compatibility matrix in lustre_dlm.h.
	50	*/
	51
	52	#define DEBUG_SUBSYSTEM S_LDLM
9fdaf8c0	53	#include "../../include/linux/libcfs/libcfs.h"
d7e09d03 PT	54
	55	#include <lustre_dlm.h>
	56	#include <obd_support.h>
	57	#include <obd.h>
	58	#include <obd_class.h>
	59	#include <lustre_lib.h>
	60
	61	#include "ldlm_internal.h"
	62
	63
	64	/* When a lock is cancelled by a client, the KMS may undergo change if this
	65	* is the "highest lock". This function returns the new KMS value.
	66	* Caller must hold lr_lock already.
	67	*
	68	* NB: A lock on [x,y] protects a KMS of up to y + 1 bytes! */
	69	__u64 ldlm_extent_shift_kms(struct ldlm_lock *lock, __u64 old_kms)
	70	{
	71	struct ldlm_resource *res = lock->l_resource;
	72	struct list_head *tmp;
	73	struct ldlm_lock *lck;
	74	__u64 kms = 0;
d7e09d03 PT	75
	76	/* don't let another thread in ldlm_extent_shift_kms race in
	77	* just after we finish and take our lock into account in its
	78	* calculation of the kms */
	79	lock->l_flags \|= LDLM_FL_KMS_IGNORE;
	80
	81	list_for_each(tmp, &res->lr_granted) {
	82	lck = list_entry(tmp, struct ldlm_lock, l_res_link);
	83
	84	if (lck->l_flags & LDLM_FL_KMS_IGNORE)
	85	continue;
	86
	87	if (lck->l_policy_data.l_extent.end >= old_kms)
0a3bdb00	88	return old_kms;
d7e09d03 PT	89
	90	/* This extent _has_ to be smaller than old_kms (checked above)
	91	* so kms can only ever be smaller or the same as old_kms. */
	92	if (lck->l_policy_data.l_extent.end + 1 > kms)
	93	kms = lck->l_policy_data.l_extent.end + 1;
	94	}
	95	LASSERTF(kms <= old_kms, "kms "LPU64" old_kms "LPU64"\n", kms, old_kms);
	96
0a3bdb00	97	return kms;
d7e09d03 PT	98	}
	99	EXPORT_SYMBOL(ldlm_extent_shift_kms);
	100
	101	struct kmem_cache *ldlm_interval_slab;
	102	struct ldlm_interval ldlm_interval_alloc(struct ldlm_lock lock)
	103	{
	104	struct ldlm_interval *node;
d7e09d03 PT	105
d7e09d03 PT	106	LASSERT(lock->l_resource->lr_type == LDLM_EXTENT);
0be19afa	107	OBD_SLAB_ALLOC_PTR_GFP(node, ldlm_interval_slab, GFP_NOFS);
d7e09d03	108	if (node == NULL)
0a3bdb00	109	return NULL;
d7e09d03 PT	110
	111	INIT_LIST_HEAD(&node->li_group);
	112	ldlm_interval_attach(node, lock);
0a3bdb00	113	return node;
d7e09d03 PT	114	}
	115
	116	void ldlm_interval_free(struct ldlm_interval *node)
	117	{
	118	if (node) {
	119	LASSERT(list_empty(&node->li_group));
	120	LASSERT(!interval_is_intree(&node->li_node));
	121	OBD_SLAB_FREE(node, ldlm_interval_slab, sizeof(*node));
	122	}
	123	}
	124
	125	/* interval tree, for LDLM_EXTENT. */
	126	void ldlm_interval_attach(struct ldlm_interval *n,
	127	struct ldlm_lock *l)
	128	{
	129	LASSERT(l->l_tree_node == NULL);
	130	LASSERT(l->l_resource->lr_type == LDLM_EXTENT);
	131
	132	list_add_tail(&l->l_sl_policy, &n->li_group);
	133	l->l_tree_node = n;
	134	}
	135
	136	struct ldlm_interval ldlm_interval_detach(struct ldlm_lock l)
	137	{
	138	struct ldlm_interval *n = l->l_tree_node;
	139
	140	if (n == NULL)
	141	return NULL;
	142
	143	LASSERT(!list_empty(&n->li_group));
	144	l->l_tree_node = NULL;
	145	list_del_init(&l->l_sl_policy);
	146
730ebc81	147	return list_empty(&n->li_group) ? n : NULL;
d7e09d03 PT	148	}
	149
	150	static inline int lock_mode_to_index(ldlm_mode_t mode)
	151	{
	152	int index;
	153
	154	LASSERT(mode != 0);
	155	LASSERT(IS_PO2(mode));
	156	for (index = -1; mode; index++, mode >>= 1) ;
	157	LASSERT(index < LCK_MODE_NUM);
	158	return index;
	159	}
	160
	161	/** Add newly granted lock into interval tree for the resource. */
	162	void ldlm_extent_add_lock(struct ldlm_resource *res,
	163	struct ldlm_lock *lock)
	164	{
	165	struct interval_node found, *root;
	166	struct ldlm_interval *node;
	167	struct ldlm_extent *extent;
	168	int idx;
	169
	170	LASSERT(lock->l_granted_mode == lock->l_req_mode);
	171
	172	node = lock->l_tree_node;
	173	LASSERT(node != NULL);
	174	LASSERT(!interval_is_intree(&node->li_node));
	175
	176	idx = lock_mode_to_index(lock->l_granted_mode);
	177	LASSERT(lock->l_granted_mode == 1 << idx);
	178	LASSERT(lock->l_granted_mode == res->lr_itree[idx].lit_mode);
	179
	180	/* node extent initialize */
	181	extent = &lock->l_policy_data.l_extent;
	182	interval_set(&node->li_node, extent->start, extent->end);
	183
	184	root = &res->lr_itree[idx].lit_root;
	185	found = interval_insert(&node->li_node, root);
	186	if (found) { /* The policy group found. */
	187	struct ldlm_interval *tmp = ldlm_interval_detach(lock);
	188	LASSERT(tmp != NULL);
	189	ldlm_interval_free(tmp);
	190	ldlm_interval_attach(to_ldlm_interval(found), lock);
	191	}
	192	res->lr_itree[idx].lit_size++;
	193
	194	/* even though we use interval tree to manage the extent lock, we also
	195	* add the locks into grant list, for debug purpose, .. */
	196	ldlm_resource_add_lock(res, &res->lr_granted, lock);
	197	}
	198
	199	/** Remove cancelled lock from resource interval tree. */
	200	void ldlm_extent_unlink_lock(struct ldlm_lock *lock)
	201	{
	202	struct ldlm_resource *res = lock->l_resource;
	203	struct ldlm_interval *node = lock->l_tree_node;
	204	struct ldlm_interval_tree *tree;
	205	int idx;
	206
	207	if (!node \|\| !interval_is_intree(&node->li_node)) /* duplicate unlink */
	208	return;
	209
	210	idx = lock_mode_to_index(lock->l_granted_mode);
	211	LASSERT(lock->l_granted_mode == 1 << idx);
212	tree = &res->lr_itree[idx];
213
214	LASSERT(tree->lit_root != NULL); /* assure the tree is not null */
215
216	tree->lit_size--;
217	node = ldlm_interval_detach(lock);
218	if (node) {
219	interval_erase(&node->li_node, &tree->lit_root);
220	ldlm_interval_free(node);
221	}
222	}
223
224	void ldlm_extent_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
225	ldlm_policy_data_t *lpolicy)
226	{
227	memset(lpolicy, 0, sizeof(*lpolicy));
228	lpolicy->l_extent.start = wpolicy->l_extent.start;
229	lpolicy->l_extent.end = wpolicy->l_extent.end;
230	lpolicy->l_extent.gid = wpolicy->l_extent.gid;
231	}
232
233	void ldlm_extent_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
234	ldlm_wire_policy_data_t *wpolicy)
235	{
236	memset(wpolicy, 0, sizeof(*wpolicy));
237	wpolicy->l_extent.start = lpolicy->l_extent.start;
238	wpolicy->l_extent.end = lpolicy->l_extent.end;
239	wpolicy->l_extent.gid = lpolicy->l_extent.gid;
240	}