xref: /dragonfly/sys/vfs/hpfs/hpfs_hash.c (revision 2cd2d2b5)
1 /*
2  * Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)ufs_ihash.c	8.7 (Berkeley) 5/17/95
34  * $FreeBSD: src/sys/fs/hpfs/hpfs_hash.c,v 1.1 1999/12/09 19:09:58 semenu Exp $
35  * $DragonFly: src/sys/vfs/hpfs/hpfs_hash.c,v 1.11 2004/04/11 18:17:21 cpressey Exp $
36  */
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/vnode.h>
43 #include <sys/mount.h>
44 #include <sys/malloc.h>
45 #include <sys/proc.h>
46 
47 #include "hpfs.h"
48 
49 MALLOC_DEFINE(M_HPFSHASH, "HPFS hash", "HPFS node hash tables");
50 
51 /*
52  * Structures associated with hpfsnode cacheing.
53  */
54 static LIST_HEAD(hphashhead, hpfsnode) *hpfs_hphashtbl;
55 static u_long	hpfs_hphash;		/* size of hash table - 1 */
56 #define	HPNOHASH(dev, lsn)	(&hpfs_hphashtbl[(minor(dev) + (lsn)) & hpfs_hphash])
57 #ifndef NULL_SIMPLELOCKS
58 static struct lwkt_token hpfs_hphash_token;
59 #endif
60 struct lock hpfs_hphash_lock;
61 
62 /*
63  * Initialize inode hash table.
64  */
65 void
66 hpfs_hphashinit(void)
67 {
68 
69 	lockinit (&hpfs_hphash_lock, 0, "hpfs_hphashlock", 0, 0);
70 	hpfs_hphashtbl = HASHINIT(desiredvnodes, M_HPFSHASH, M_WAITOK,
71 	    &hpfs_hphash);
72 	lwkt_token_init(&hpfs_hphash_token);
73 }
74 
75 /*
76  * Free the inode hash.
77  */
78 int
79 hpfs_hphash_uninit(struct vfsconf *vfc)
80 {
81 	lwkt_tokref ilock;
82 
83 	lwkt_gettoken(&ilock, &hpfs_hphash_token);
84 	if (hpfs_hphashtbl)
85 		free(hpfs_hphashtbl, M_HPFSHASH);
86 	lwkt_reltoken(&ilock);
87 
88 	return 0;
89 }
90 
91 /*
92  * Use the device/inum pair to find the incore inode, and return a pointer
93  * to it. If it is in core, return it, even if it is locked.
94  */
95 struct hpfsnode *
96 hpfs_hphashlookup(dev_t dev, lsn_t ino)
97 {
98 	struct hpfsnode *hp;
99 	lwkt_tokref ilock;
100 
101 	lwkt_gettoken(&ilock, &hpfs_hphash_token);
102 	for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
103 		if (ino == hp->h_no && dev == hp->h_dev)
104 			break;
105 	}
106 	lwkt_reltoken(&ilock);
107 
108 	return (hp);
109 }
110 
111 struct vnode *
112 hpfs_hphashvget(dev_t dev, lsn_t ino, struct thread *td)
113 {
114 	struct hpfsnode *hp;
115 	lwkt_tokref ilock;
116 	lwkt_tokref vlock;
117 	struct vnode *vp;
118 
119 	lwkt_gettoken(&ilock, &hpfs_hphash_token);
120 loop:
121 	for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
122 		if (ino != hp->h_no || dev != hp->h_dev)
123 			continue;
124 		vp = HPTOV(hp);
125 		lwkt_gettoken (&vlock, vp->v_interlock);
126 
127 		/*
128 		 * We must check to see if the inode has been ripped
129 		 * out from under us after blocking.
130 		 */
131 		for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
132 			if (ino == hp->h_no && dev == hp->h_dev)
133 				break;
134 		}
135 		if (hp == NULL || vp != HPTOV(hp)) {
136 			lwkt_reltoken(&vlock);
137 			goto loop;
138 		}
139 
140 		/*
141 		 * Or if the vget fails (due to a race)
142 		 */
143 		if (vget(vp, &vlock, LK_EXCLUSIVE | LK_INTERLOCK, td))
144 			goto loop;
145 		lwkt_reltoken(&ilock);
146 		return (vp);
147 	}
148 	lwkt_reltoken(&ilock);
149 	return (NULLVP);
150 }
151 
152 /*
153  * Insert the hpfsnode into the hash table.
154  */
155 void
156 hpfs_hphashins(struct hpfsnode *hp)
157 {
158 	struct hphashhead *hpp;
159 	lwkt_tokref ilock;
160 
161 	lwkt_gettoken(&ilock, &hpfs_hphash_token);
162 	hpp = HPNOHASH(hp->h_dev, hp->h_no);
163 	hp->h_flag |= H_HASHED;
164 	LIST_INSERT_HEAD(hpp, hp, h_hash);
165 	lwkt_reltoken(&ilock);
166 }
167 
168 /*
169  * Remove the inode from the hash table.
170  */
171 void
172 hpfs_hphashrem(struct hpfsnode *hp)
173 {
174 	lwkt_tokref ilock;
175 
176 	lwkt_gettoken(&ilock, &hpfs_hphash_token);
177 	if (hp->h_flag & H_HASHED) {
178 		hp->h_flag &= ~H_HASHED;
179 		LIST_REMOVE(hp, h_hash);
180 #ifdef DIAGNOSTIC
181 		hp->h_hash.le_next = NULL;
182 		hp->h_hash.le_prev = NULL;
183 #endif
184 	}
185 	lwkt_reltoken(&ilock);
186 }
187