1 /* $NetBSD: chfs_vnode_cache.c,v 1.3 2012/10/19 12:44:39 ttoth Exp $ */
2
3 /*-
4 * Copyright (c) 2010 Department of Software Engineering,
5 * University of Szeged, Hungary
6 * Copyright (C) 2010 Tamas Toth <ttoth@inf.u-szeged.hu>
7 * Copyright (C) 2010 Adam Hoka <ahoka@NetBSD.org>
8 * All rights reserved.
9 *
10 * This code is derived from software contributed to The NetBSD Foundation
11 * by the Department of Software Engineering, University of Szeged, Hungary
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include "chfs.h"
36 #include <sys/pool.h>
37
38 /* vnode cache is a hashtable for vnodes */
39
40 /* chfs_vnocache_hash_init - initializing the hashtable */
41 struct chfs_vnode_cache **
chfs_vnocache_hash_init(void)42 chfs_vnocache_hash_init(void)
43 {
44 return kmem_zalloc(VNODECACHE_SIZE *
45 sizeof(struct chfs_vnode_cache *), KM_SLEEP);
46 }
47
48 /*
49 * chfs_vnode_cache_get - get a vnode_cache from the hashtable
50 * Returns the vnode_cache.
51 */
52 struct chfs_vnode_cache *
chfs_vnode_cache_get(struct chfs_mount * chmp,ino_t vno)53 chfs_vnode_cache_get(struct chfs_mount *chmp, ino_t vno)
54 {
55 struct chfs_vnode_cache* ret;
56
57 KASSERT(mutex_owned(&chmp->chm_lock_vnocache));
58
59 ret = chmp->chm_vnocache_hash[vno % VNODECACHE_SIZE];
60
61 if (ret == NULL) {
62 return NULL;
63 }
64
65 while (ret && ret->vno < vno) {
66 ret = ret->next;
67 }
68
69 if (ret && ret->vno != vno) {
70 ret = NULL;
71 }
72
73 return ret;
74 }
75
76 /* chfs_vnode_cache_add - add a vnode_cache to the hashtable */
77 void
chfs_vnode_cache_add(struct chfs_mount * chmp,struct chfs_vnode_cache * new)78 chfs_vnode_cache_add(struct chfs_mount *chmp,
79 struct chfs_vnode_cache* new)
80 {
81 struct chfs_vnode_cache** prev;
82
83 KASSERT(mutex_owned(&chmp->chm_lock_vnocache));
84
85 if (!new->vno) {
86 new->vno = ++chmp->chm_max_vno;
87 }
88
89 prev = &chmp->chm_vnocache_hash[new->vno % VNODECACHE_SIZE];
90
91 while ((*prev) && (*prev)->vno < new->vno) {
92 prev = &((*prev)->next);
93 }
94 new->next = *prev;
95 *prev = new;
96 }
97
98 /* chfs_vnode_cache_remove - removes a vnode_cache from the hashtable */
99 void
chfs_vnode_cache_remove(struct chfs_mount * chmp,struct chfs_vnode_cache * old)100 chfs_vnode_cache_remove(struct chfs_mount *chmp,
101 struct chfs_vnode_cache* old)
102 {
103 struct chfs_vnode_cache** prev;
104
105 KASSERT(mutex_owned(&chmp->chm_lock_vnocache));
106
107 prev = &chmp->chm_vnocache_hash[old->vno % VNODECACHE_SIZE];
108 while ((*prev) && (*prev)->vno < old->vno) {
109 prev = &(*prev)->next;
110 }
111
112 if ((*prev) == old) {
113 *prev = old->next;
114 }
115
116 if (old->state != VNO_STATE_READING &&
117 old->state != VNO_STATE_CLEARING) {
118 chfs_vnode_cache_free(old);
119 }
120 }
121
122 /* chfs_vnocache_hash_destroy - destroying the vnode cache */
123 void
chfs_vnocache_hash_destroy(struct chfs_vnode_cache ** hash)124 chfs_vnocache_hash_destroy(struct chfs_vnode_cache **hash)
125 {
126 struct chfs_vnode_cache *this, *next;
127 int i;
128
129 /* free every row */
130 for (i = 0; i < VNODECACHE_SIZE; i++) {
131 this = hash[i];
132 while (this) {
133 next = this->next;
134 chfs_vnode_cache_free(this);
135 this = next;
136 }
137 hash[i] = NULL;
138 }
139 }
140
141