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) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
29 *
30 * Copyright (c) 2011, 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/obdclass/lustre_handles.c
37 *
38 * Author: Phil Schwan <phil@clusterfs.com>
39 */
40
41 #define DEBUG_SUBSYSTEM S_CLASS
42
43 #include "../include/obd_support.h"
44 #include "../include/lustre_handles.h"
45 #include "../include/lustre_lib.h"
46
47 static __u64 handle_base;
48 #define HANDLE_INCR 7
49 static spinlock_t handle_base_lock;
50
51 static struct handle_bucket {
52 spinlock_t lock;
53 struct list_head head;
54 } *handle_hash;
55
56 #define HANDLE_HASH_SIZE (1 << 16)
57 #define HANDLE_HASH_MASK (HANDLE_HASH_SIZE - 1)
58
59 /*
60 * Generate a unique 64bit cookie (hash) for a handle and insert it into
61 * global (per-node) hash-table.
62 */
class_handle_hash(struct portals_handle * h,struct portals_handle_ops * ops)63 void class_handle_hash(struct portals_handle *h,
64 struct portals_handle_ops *ops)
65 {
66 struct handle_bucket *bucket;
67
68 LASSERT(h != NULL);
69 LASSERT(list_empty(&h->h_link));
70
71 /*
72 * This is fast, but simplistic cookie generation algorithm, it will
73 * need a re-do at some point in the future for security.
74 */
75 spin_lock(&handle_base_lock);
76 handle_base += HANDLE_INCR;
77
78 if (unlikely(handle_base == 0)) {
79 /*
80 * Cookie of zero is "dangerous", because in many places it's
81 * assumed that 0 means "unassigned" handle, not bound to any
82 * object.
83 */
84 CWARN("The universe has been exhausted: cookie wrap-around.\n");
85 handle_base += HANDLE_INCR;
86 }
87 h->h_cookie = handle_base;
88 spin_unlock(&handle_base_lock);
89
90 h->h_ops = ops;
91 spin_lock_init(&h->h_lock);
92
93 bucket = &handle_hash[h->h_cookie & HANDLE_HASH_MASK];
94 spin_lock(&bucket->lock);
95 list_add_rcu(&h->h_link, &bucket->head);
96 h->h_in = 1;
97 spin_unlock(&bucket->lock);
98
99 CDEBUG(D_INFO, "added object %p with handle %#llx to hash\n",
100 h, h->h_cookie);
101 }
102 EXPORT_SYMBOL(class_handle_hash);
103
class_handle_unhash_nolock(struct portals_handle * h)104 static void class_handle_unhash_nolock(struct portals_handle *h)
105 {
106 if (list_empty(&h->h_link)) {
107 CERROR("removing an already-removed handle (%#llx)\n",
108 h->h_cookie);
109 return;
110 }
111
112 CDEBUG(D_INFO, "removing object %p with handle %#llx from hash\n",
113 h, h->h_cookie);
114
115 spin_lock(&h->h_lock);
116 if (h->h_in == 0) {
117 spin_unlock(&h->h_lock);
118 return;
119 }
120 h->h_in = 0;
121 spin_unlock(&h->h_lock);
122 list_del_rcu(&h->h_link);
123 }
124
class_handle_unhash(struct portals_handle * h)125 void class_handle_unhash(struct portals_handle *h)
126 {
127 struct handle_bucket *bucket;
128
129 bucket = handle_hash + (h->h_cookie & HANDLE_HASH_MASK);
130
131 spin_lock(&bucket->lock);
132 class_handle_unhash_nolock(h);
133 spin_unlock(&bucket->lock);
134 }
135 EXPORT_SYMBOL(class_handle_unhash);
136
class_handle2object(__u64 cookie)137 void *class_handle2object(__u64 cookie)
138 {
139 struct handle_bucket *bucket;
140 struct portals_handle *h;
141 void *retval = NULL;
142
143 LASSERT(handle_hash != NULL);
144
145 /* Be careful when you want to change this code. See the
146 * rcu_read_lock() definition on top this file. - jxiong */
147 bucket = handle_hash + (cookie & HANDLE_HASH_MASK);
148
149 rcu_read_lock();
150 list_for_each_entry_rcu(h, &bucket->head, h_link) {
151 if (h->h_cookie != cookie)
152 continue;
153
154 spin_lock(&h->h_lock);
155 if (likely(h->h_in != 0)) {
156 h->h_ops->hop_addref(h);
157 retval = h;
158 }
159 spin_unlock(&h->h_lock);
160 break;
161 }
162 rcu_read_unlock();
163
164 return retval;
165 }
166 EXPORT_SYMBOL(class_handle2object);
167
class_handle_free_cb(struct rcu_head * rcu)168 void class_handle_free_cb(struct rcu_head *rcu)
169 {
170 struct portals_handle *h = RCU2HANDLE(rcu);
171 void *ptr = (void *)(unsigned long)h->h_cookie;
172
173 if (h->h_ops->hop_free != NULL)
174 h->h_ops->hop_free(ptr, h->h_size);
175 else
176 kfree(ptr);
177 }
178 EXPORT_SYMBOL(class_handle_free_cb);
179
class_handle_init(void)180 int class_handle_init(void)
181 {
182 struct handle_bucket *bucket;
183 struct timespec64 ts;
184 int seed[2];
185
186 LASSERT(handle_hash == NULL);
187
188 handle_hash = libcfs_kvzalloc(sizeof(*bucket) * HANDLE_HASH_SIZE,
189 GFP_NOFS);
190 if (handle_hash == NULL)
191 return -ENOMEM;
192
193 spin_lock_init(&handle_base_lock);
194 for (bucket = handle_hash + HANDLE_HASH_SIZE - 1; bucket >= handle_hash;
195 bucket--) {
196 INIT_LIST_HEAD(&bucket->head);
197 spin_lock_init(&bucket->lock);
198 }
199
200 /** bug 21430: add randomness to the initial base */
201 cfs_get_random_bytes(seed, sizeof(seed));
202 ktime_get_ts64(&ts);
203 cfs_srand(ts.tv_sec ^ seed[0], ts.tv_nsec ^ seed[1]);
204
205 cfs_get_random_bytes(&handle_base, sizeof(handle_base));
206 LASSERT(handle_base != 0ULL);
207
208 return 0;
209 }
210
cleanup_all_handles(void)211 static int cleanup_all_handles(void)
212 {
213 int rc;
214 int i;
215
216 for (rc = i = 0; i < HANDLE_HASH_SIZE; i++) {
217 struct portals_handle *h;
218
219 spin_lock(&handle_hash[i].lock);
220 list_for_each_entry_rcu(h, &(handle_hash[i].head), h_link) {
221 CERROR("force clean handle %#llx addr %p ops %p\n",
222 h->h_cookie, h, h->h_ops);
223
224 class_handle_unhash_nolock(h);
225 rc++;
226 }
227 spin_unlock(&handle_hash[i].lock);
228 }
229
230 return rc;
231 }
232
class_handle_cleanup(void)233 void class_handle_cleanup(void)
234 {
235 int count;
236
237 LASSERT(handle_hash != NULL);
238
239 count = cleanup_all_handles();
240
241 kvfree(handle_hash);
242 handle_hash = NULL;
243
244 if (count != 0)
245 CERROR("handle_count at cleanup: %d\n", count);
246 }
247