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
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"
60
61 /* When a lock is cancelled by a client, the KMS may undergo change if this
62 * is the "highest lock". This function returns the new KMS value.
63 * Caller must hold lr_lock already.
64 *
65 * NB: A lock on [x,y] protects a KMS of up to y + 1 bytes! */
ldlm_extent_shift_kms(struct ldlm_lock * lock,__u64 old_kms)66 __u64 ldlm_extent_shift_kms(struct ldlm_lock *lock, __u64 old_kms)
67 {
68 struct ldlm_resource *res = lock->l_resource;
69 struct list_head *tmp;
70 struct ldlm_lock *lck;
71 __u64 kms = 0;
72
73 /* don't let another thread in ldlm_extent_shift_kms race in
74 * just after we finish and take our lock into account in its
75 * calculation of the kms */
76 lock->l_flags |= LDLM_FL_KMS_IGNORE;
77
78 list_for_each(tmp, &res->lr_granted) {
79 lck = list_entry(tmp, struct ldlm_lock, l_res_link);
80
81 if (lck->l_flags & LDLM_FL_KMS_IGNORE)
82 continue;
83
84 if (lck->l_policy_data.l_extent.end >= old_kms)
85 return old_kms;
86
87 /* This extent _has_ to be smaller than old_kms (checked above)
88 * so kms can only ever be smaller or the same as old_kms. */
89 if (lck->l_policy_data.l_extent.end + 1 > kms)
90 kms = lck->l_policy_data.l_extent.end + 1;
91 }
92 LASSERTF(kms <= old_kms, "kms %llu old_kms %llu\n", kms, old_kms);
93
94 return kms;
95 }
96 EXPORT_SYMBOL(ldlm_extent_shift_kms);
97
98 struct kmem_cache *ldlm_interval_slab;
99
100 /* interval tree, for LDLM_EXTENT. */
ldlm_interval_attach(struct ldlm_interval * n,struct ldlm_lock * l)101 static void ldlm_interval_attach(struct ldlm_interval *n, struct ldlm_lock *l)
102 {
103 LASSERT(!l->l_tree_node);
104 LASSERT(l->l_resource->lr_type == LDLM_EXTENT);
105
106 list_add_tail(&l->l_sl_policy, &n->li_group);
107 l->l_tree_node = n;
108 }
109
ldlm_interval_alloc(struct ldlm_lock * lock)110 struct ldlm_interval *ldlm_interval_alloc(struct ldlm_lock *lock)
111 {
112 struct ldlm_interval *node;
113
114 LASSERT(lock->l_resource->lr_type == LDLM_EXTENT);
115 node = kmem_cache_alloc(ldlm_interval_slab, GFP_NOFS | __GFP_ZERO);
116 if (node == NULL)
117 return NULL;
118
119 INIT_LIST_HEAD(&node->li_group);
120 ldlm_interval_attach(node, lock);
121 return node;
122 }
123
ldlm_interval_free(struct ldlm_interval * node)124 void ldlm_interval_free(struct ldlm_interval *node)
125 {
126 if (node) {
127 LASSERT(list_empty(&node->li_group));
128 LASSERT(!interval_is_intree(&node->li_node));
129 kmem_cache_free(ldlm_interval_slab, node);
130 }
131 }
132
ldlm_interval_detach(struct ldlm_lock * l)133 struct ldlm_interval *ldlm_interval_detach(struct ldlm_lock *l)
134 {
135 struct ldlm_interval *n = l->l_tree_node;
136
137 if (n == NULL)
138 return NULL;
139
140 LASSERT(!list_empty(&n->li_group));
141 l->l_tree_node = NULL;
142 list_del_init(&l->l_sl_policy);
143
144 return list_empty(&n->li_group) ? n : NULL;
145 }
146
lock_mode_to_index(ldlm_mode_t mode)147 static inline int lock_mode_to_index(ldlm_mode_t mode)
148 {
149 int index;
150
151 LASSERT(mode != 0);
152 LASSERT(IS_PO2(mode));
153 for (index = -1; mode; index++)
154 mode >>= 1;
155 LASSERT(index < LCK_MODE_NUM);
156 return index;
157 }
158
159 /** Add newly granted lock into interval tree for the resource. */
ldlm_extent_add_lock(struct ldlm_resource * res,struct ldlm_lock * lock)160 void ldlm_extent_add_lock(struct ldlm_resource *res,
161 struct ldlm_lock *lock)
162 {
163 struct interval_node *found, **root;
164 struct ldlm_interval *node;
165 struct ldlm_extent *extent;
166 int idx;
167
168 LASSERT(lock->l_granted_mode == lock->l_req_mode);
169
170 node = lock->l_tree_node;
171 LASSERT(node != NULL);
172 LASSERT(!interval_is_intree(&node->li_node));
173
174 idx = lock_mode_to_index(lock->l_granted_mode);
175 LASSERT(lock->l_granted_mode == 1 << idx);
176 LASSERT(lock->l_granted_mode == res->lr_itree[idx].lit_mode);
177
178 /* node extent initialize */
179 extent = &lock->l_policy_data.l_extent;
180 interval_set(&node->li_node, extent->start, extent->end);
181
182 root = &res->lr_itree[idx].lit_root;
183 found = interval_insert(&node->li_node, root);
184 if (found) { /* The policy group found. */
185 struct ldlm_interval *tmp;
186
187 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. */
ldlm_extent_unlink_lock(struct ldlm_lock * lock)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
ldlm_extent_policy_wire_to_local(const ldlm_wire_policy_data_t * wpolicy,ldlm_policy_data_t * lpolicy)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
ldlm_extent_policy_local_to_wire(const ldlm_policy_data_t * lpolicy,ldlm_wire_policy_data_t * wpolicy)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 }
241