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* 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 "../include/lustre_dlm.h"
#include "../include/obd_support.h"
#include "../include/obd.h"
#include "../include/obd_class.h"
#include "../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 %llu old_kms %llu\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;
}
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