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
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.
65 *
66 * 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)67 __u64 ldlm_extent_shift_kms(struct ldlm_lock *lock, __u64 old_kms)
68 {
69 struct ldlm_resource *res = lock->l_resource;
70 struct list_head *tmp;
71 struct ldlm_lock *lck;
72 __u64 kms = 0;
73
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;
78
79 list_for_each(tmp, &res->lr_granted) {
80 lck = list_entry(tmp, struct ldlm_lock, l_res_link);
81
82 if (lck->l_flags & LDLM_FL_KMS_IGNORE)
83 continue;
84
85 if (lck->l_policy_data.l_extent.end >= old_kms)
86 return old_kms;
87
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;
92 }
93 LASSERTF(kms <= old_kms, "kms %llu old_kms %llu\n", kms, old_kms);
94
95 return kms;
96 }
97 EXPORT_SYMBOL(ldlm_extent_shift_kms);
98
99 struct kmem_cache *ldlm_interval_slab;
ldlm_interval_alloc(struct ldlm_lock * lock)100 struct ldlm_interval *ldlm_interval_alloc(struct ldlm_lock *lock)
101 {
102 struct ldlm_interval *node;
103
104 LASSERT(lock->l_resource->lr_type == LDLM_EXTENT);
105 OBD_SLAB_ALLOC_PTR_GFP(node, ldlm_interval_slab, GFP_NOFS);
106 if (node == NULL)
107 return NULL;
108
109 INIT_LIST_HEAD(&node->li_group);
110 ldlm_interval_attach(node, lock);
111 return node;
112 }
113
ldlm_interval_free(struct ldlm_interval * node)114 void ldlm_interval_free(struct ldlm_interval *node)
115 {
116 if (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));
120 }
121 }
122
123 /* interval tree, for LDLM_EXTENT. */
ldlm_interval_attach(struct ldlm_interval * n,struct ldlm_lock * l)124 void ldlm_interval_attach(struct ldlm_interval *n,
125 struct ldlm_lock *l)
126 {
127 LASSERT(l->l_tree_node == NULL);
128 LASSERT(l->l_resource->lr_type == LDLM_EXTENT);
129
130 list_add_tail(&l->l_sl_policy, &n->li_group);
131 l->l_tree_node = n;
132 }
133
ldlm_interval_detach(struct ldlm_lock * l)134 struct ldlm_interval *ldlm_interval_detach(struct ldlm_lock *l)
135 {
136 struct ldlm_interval *n = l->l_tree_node;
137
138 if (n == NULL)
139 return NULL;
140
141 LASSERT(!list_empty(&n->li_group));
142 l->l_tree_node = NULL;
143 list_del_init(&l->l_sl_policy);
144
145 return list_empty(&n->li_group) ? n : NULL;
146 }
147
lock_mode_to_index(ldlm_mode_t mode)148 static inline int lock_mode_to_index(ldlm_mode_t mode)
149 {
150 int index;
151
152 LASSERT(mode != 0);
153 LASSERT(IS_PO2(mode));
154 for (index = -1; mode; index++)
155 mode >>= 1;
156 LASSERT(index < LCK_MODE_NUM);
157 return index;
158 }
159
160 /** Add newly granted lock into interval tree for the resource. */
ldlm_extent_add_lock(struct ldlm_resource * res,struct ldlm_lock * lock)161 void ldlm_extent_add_lock(struct ldlm_resource *res,
162 struct ldlm_lock *lock)
163 {
164 struct interval_node *found, **root;
165 struct ldlm_interval *node;
166 struct ldlm_extent *extent;
167 int idx;
168
169 LASSERT(lock->l_granted_mode == lock->l_req_mode);
170
171 node = lock->l_tree_node;
172 LASSERT(node != NULL);
173 LASSERT(!interval_is_intree(&node->li_node));
174
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);
178
179 /* node extent initialize */
180 extent = &lock->l_policy_data.l_extent;
181 interval_set(&node->li_node, extent->start, extent->end);
182
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;
187
188 tmp = ldlm_interval_detach(lock);
189 LASSERT(tmp != NULL);
190 ldlm_interval_free(tmp);
191 ldlm_interval_attach(to_ldlm_interval(found), lock);
192 }
193 res->lr_itree[idx].lit_size++;
194
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);
198 }
199
200 /** Remove cancelled lock from resource interval tree. */
ldlm_extent_unlink_lock(struct ldlm_lock * lock)201 void ldlm_extent_unlink_lock(struct ldlm_lock *lock)
202 {
203 struct ldlm_resource *res = lock->l_resource;
204 struct ldlm_interval *node = lock->l_tree_node;
205 struct ldlm_interval_tree *tree;
206 int idx;
207
208 if (!node || !interval_is_intree(&node->li_node)) /* duplicate unlink */
209 return;
210
211 idx = lock_mode_to_index(lock->l_granted_mode);
212 LASSERT(lock->l_granted_mode == 1 << idx);
213 tree = &res->lr_itree[idx];
214
215 LASSERT(tree->lit_root != NULL); /* assure the tree is not null */
216
217 tree->lit_size--;
218 node = ldlm_interval_detach(lock);
219 if (node) {
220 interval_erase(&node->li_node, &tree->lit_root);
221 ldlm_interval_free(node);
222 }
223 }
224
ldlm_extent_policy_wire_to_local(const ldlm_wire_policy_data_t * wpolicy,ldlm_policy_data_t * lpolicy)225 void ldlm_extent_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
226 ldlm_policy_data_t *lpolicy)
227 {
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;
232 }
233
ldlm_extent_policy_local_to_wire(const ldlm_policy_data_t * lpolicy,ldlm_wire_policy_data_t * wpolicy)234 void ldlm_extent_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
235 ldlm_wire_policy_data_t *wpolicy)
236 {
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;
241 }
242