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14 * in the LICENSE file that accompanied this code).
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27 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
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33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
36 * lustre/ldlm/ldlm_extent.c
38 * Author: Peter Braam <braam@clusterfs.com>
39 * Author: Phil Schwan <phil@clusterfs.com>
43 * This file contains implementation of EXTENT lock type
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.
52 #define DEBUG_SUBSYSTEM S_LDLM
53 #include "../../include/linux/libcfs/libcfs.h"
54 #include "../include/lustre_dlm.h"
55 #include "../include/obd_support.h"
56 #include "../include/obd.h"
57 #include "../include/obd_class.h"
58 #include "../include/lustre_lib.h"
59 #include "ldlm_internal.h"
62 /* When a lock is cancelled by a client, the KMS may undergo change if this
63 * is the "highest lock". This function returns the new KMS value.
64 * Caller must hold lr_lock already.
66 * NB: A lock on [x,y] protects a KMS of up to y + 1 bytes! */
67 __u64 ldlm_extent_shift_kms(struct ldlm_lock *lock, __u64 old_kms)
69 struct ldlm_resource *res = lock->l_resource;
70 struct list_head *tmp;
71 struct ldlm_lock *lck;
74 /* don't let another thread in ldlm_extent_shift_kms race in
75 * just after we finish and take our lock into account in its
76 * calculation of the kms */
77 lock->l_flags |= LDLM_FL_KMS_IGNORE;
79 list_for_each(tmp, &res->lr_granted) {
80 lck = list_entry(tmp, struct ldlm_lock, l_res_link);
82 if (lck->l_flags & LDLM_FL_KMS_IGNORE)
85 if (lck->l_policy_data.l_extent.end >= old_kms)
88 /* This extent _has_ to be smaller than old_kms (checked above)
89 * so kms can only ever be smaller or the same as old_kms. */
90 if (lck->l_policy_data.l_extent.end + 1 > kms)
91 kms = lck->l_policy_data.l_extent.end + 1;
93 LASSERTF(kms <= old_kms, "kms %llu old_kms %llu\n", kms, old_kms);
97 EXPORT_SYMBOL(ldlm_extent_shift_kms);
99 struct kmem_cache *ldlm_interval_slab;
100 struct ldlm_interval *ldlm_interval_alloc(struct ldlm_lock *lock)
102 struct ldlm_interval *node;
104 LASSERT(lock->l_resource->lr_type == LDLM_EXTENT);
105 OBD_SLAB_ALLOC_PTR_GFP(node, ldlm_interval_slab, GFP_NOFS);
109 INIT_LIST_HEAD(&node->li_group);
110 ldlm_interval_attach(node, lock);
114 void ldlm_interval_free(struct ldlm_interval *node)
117 LASSERT(list_empty(&node->li_group));
118 LASSERT(!interval_is_intree(&node->li_node));
119 OBD_SLAB_FREE(node, ldlm_interval_slab, sizeof(*node));
123 /* interval tree, for LDLM_EXTENT. */
124 void ldlm_interval_attach(struct ldlm_interval *n,
127 LASSERT(l->l_tree_node == NULL);
128 LASSERT(l->l_resource->lr_type == LDLM_EXTENT);
130 list_add_tail(&l->l_sl_policy, &n->li_group);
134 struct ldlm_interval *ldlm_interval_detach(struct ldlm_lock *l)
136 struct ldlm_interval *n = l->l_tree_node;
141 LASSERT(!list_empty(&n->li_group));
142 l->l_tree_node = NULL;
143 list_del_init(&l->l_sl_policy);
145 return list_empty(&n->li_group) ? n : NULL;
148 static inline int lock_mode_to_index(ldlm_mode_t mode)
153 LASSERT(IS_PO2(mode));
154 for (index = -1; mode; index++)
156 LASSERT(index < LCK_MODE_NUM);
160 /** Add newly granted lock into interval tree for the resource. */
161 void ldlm_extent_add_lock(struct ldlm_resource *res,
162 struct ldlm_lock *lock)
164 struct interval_node *found, **root;
165 struct ldlm_interval *node;
166 struct ldlm_extent *extent;
169 LASSERT(lock->l_granted_mode == lock->l_req_mode);
171 node = lock->l_tree_node;
172 LASSERT(node != NULL);
173 LASSERT(!interval_is_intree(&node->li_node));
175 idx = lock_mode_to_index(lock->l_granted_mode);
176 LASSERT(lock->l_granted_mode == 1 << idx);
177 LASSERT(lock->l_granted_mode == res->lr_itree[idx].lit_mode);
179 /* node extent initialize */
180 extent = &lock->l_policy_data.l_extent;
181 interval_set(&node->li_node, extent->start, extent->end);
183 root = &res->lr_itree[idx].lit_root;
184 found = interval_insert(&node->li_node, root);
185 if (found) { /* The policy group found. */
186 struct ldlm_interval *tmp;
188 tmp = ldlm_interval_detach(lock);
189 LASSERT(tmp != NULL);
190 ldlm_interval_free(tmp);
191 ldlm_interval_attach(to_ldlm_interval(found), lock);
193 res->lr_itree[idx].lit_size++;
195 /* even though we use interval tree to manage the extent lock, we also
196 * add the locks into grant list, for debug purpose, .. */
197 ldlm_resource_add_lock(res, &res->lr_granted, lock);
200 /** Remove cancelled lock from resource interval tree. */
201 void ldlm_extent_unlink_lock(struct ldlm_lock *lock)
203 struct ldlm_resource *res = lock->l_resource;
204 struct ldlm_interval *node = lock->l_tree_node;
205 struct ldlm_interval_tree *tree;
208 if (!node || !interval_is_intree(&node->li_node)) /* duplicate unlink */
211 idx = lock_mode_to_index(lock->l_granted_mode);
212 LASSERT(lock->l_granted_mode == 1 << idx);
213 tree = &res->lr_itree[idx];
215 LASSERT(tree->lit_root != NULL); /* assure the tree is not null */
218 node = ldlm_interval_detach(lock);
220 interval_erase(&node->li_node, &tree->lit_root);
221 ldlm_interval_free(node);
225 void ldlm_extent_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
226 ldlm_policy_data_t *lpolicy)
228 memset(lpolicy, 0, sizeof(*lpolicy));
229 lpolicy->l_extent.start = wpolicy->l_extent.start;
230 lpolicy->l_extent.end = wpolicy->l_extent.end;
231 lpolicy->l_extent.gid = wpolicy->l_extent.gid;
234 void ldlm_extent_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
235 ldlm_wire_policy_data_t *wpolicy)
237 memset(wpolicy, 0, sizeof(*wpolicy));
238 wpolicy->l_extent.start = lpolicy->l_extent.start;
239 wpolicy->l_extent.end = lpolicy->l_extent.end;
240 wpolicy->l_extent.gid = lpolicy->l_extent.gid;