1/*	$OpenBSD: ntfs_ihash.c,v 1.21 2021/03/11 13:31:35 jsg Exp $	*/
2/*	$NetBSD: ntfs_ihash.c,v 1.1 2002/12/23 17:38:32 jdolecek Exp $	*/
3
4/*
5 * Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 *	@(#)ufs_ihash.c	8.7 (Berkeley) 5/17/95
33 * Id: ntfs_ihash.c,v 1.5 1999/05/12 09:42:58 semenu Exp
34 */
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/rwlock.h>
39#include <sys/vnode.h>
40#include <sys/malloc.h>
41#include <sys/mount.h>
42
43#include <crypto/siphash.h>
44
45#include <ntfs/ntfs.h>
46#include <ntfs/ntfs_inode.h>
47#include <ntfs/ntfs_ihash.h>
48
49/*
50 * Structures associated with inode caching.
51 */
52u_int ntfs_hash(dev_t, ntfsino_t);
53static LIST_HEAD(nthashhead, ntnode) *ntfs_nthashtbl;
54static SIPHASH_KEY ntfs_nthashkey;
55static u_long	ntfs_nthash;		/* size of hash table - 1 */
56#define	NTNOHASH(device, inum) ntfs_hash((device), (inum))
57struct rwlock ntfs_hashlock = RWLOCK_INITIALIZER("ntfs_nthashlock");
58
59/*
60 * Initialize inode hash table.
61 */
62void
63ntfs_nthashinit(void)
64{
65	u_long nthash;
66	void *nthashtbl;
67
68	if (ntfs_nthashtbl)
69		return;
70
71	nthashtbl = hashinit(initialvnodes, M_NTFSNTHASH, M_WAITOK, &nthash);
72	if (ntfs_nthashtbl) {
73		hashfree(nthashtbl, initialvnodes, M_NTFSNTHASH);
74		return;
75	}
76	ntfs_nthashtbl = nthashtbl;
77	ntfs_nthash = nthash;
78
79	arc4random_buf(&ntfs_nthashkey, sizeof(ntfs_nthashkey));
80}
81
82u_int
83ntfs_hash(dev_t dev, ntfsino_t inum)
84{
85	SIPHASH_CTX ctx;
86
87	SipHash24_Init(&ctx, &ntfs_nthashkey);
88	SipHash24_Update(&ctx, &dev, sizeof(dev));
89	SipHash24_Update(&ctx, &inum, sizeof(inum));
90
91	return (SipHash24_End(&ctx) & ntfs_nthash);
92}
93
94/*
95 * Use the device/inum pair to find the incore inode, and return a pointer
96 * to it. If it is in core, return it, even if it is locked.
97 */
98struct ntnode *
99ntfs_nthashlookup(dev_t dev, ntfsino_t inum)
100{
101	struct ntnode *ip;
102	struct nthashhead *ipp;
103
104	/* XXXLOCKING lock hash list? */
105	ipp = &ntfs_nthashtbl[NTNOHASH(dev, inum)];
106	LIST_FOREACH(ip, ipp, i_hash) {
107		if (inum == ip->i_number && dev == ip->i_dev)
108			break;
109	}
110	/* XXXLOCKING unlock hash list? */
111
112	return (ip);
113}
114
115/*
116 * Insert the ntnode into the hash table.
117 */
118void
119ntfs_nthashins(struct ntnode *ip)
120{
121	struct nthashhead *ipp;
122
123	/* XXXLOCKING lock hash list? */
124	ipp = &ntfs_nthashtbl[NTNOHASH(ip->i_dev, ip->i_number)];
125	LIST_INSERT_HEAD(ipp, ip, i_hash);
126	ip->i_flag |= IN_HASHED;
127	/* XXXLOCKING unlock hash list? */
128}
129
130/*
131 * Remove the inode from the hash table.
132 */
133void
134ntfs_nthashrem(struct ntnode *ip)
135{
136	/* XXXLOCKING lock hash list? */
137	if (ip->i_flag & IN_HASHED) {
138		ip->i_flag &= ~IN_HASHED;
139		LIST_REMOVE(ip, i_hash);
140	}
141	/* XXXLOCKING unlock hash list? */
142}
143