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      1 /*	$NetBSD: ntfs_ihash.c,v 1.11 2015/02/20 17:08:13 maxv Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  *	@(#)ufs_ihash.c	8.7 (Berkeley) 5/17/95
     32  * Id: ntfs_ihash.c,v 1.5 1999/05/12 09:42:58 semenu Exp
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 __KERNEL_RCSID(0, "$NetBSD: ntfs_ihash.c,v 1.11 2015/02/20 17:08:13 maxv Exp $");
     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/mallocvar.h>
     45 
     46 #include <fs/ntfs/ntfs.h>
     47 #include <fs/ntfs/ntfs_inode.h>
     48 #include <fs/ntfs/ntfs_ihash.h>
     49 
     50 /*
     51  * Structures associated with inode cacheing.
     52  */
     53 static LIST_HEAD(nthashhead, ntnode) *ntfs_nthashtbl;
     54 static u_long	ntfs_nthash;		/* size of hash table - 1 */
     55 #define	NTNOHASH(device, inum)	((minor(device) + (inum)) & ntfs_nthash)
     56 static kmutex_t ntfs_nthash_lock;
     57 kmutex_t ntfs_hashlock;
     58 
     59 /*
     60  * Initialize inode hash table.
     61  */
     62 void
     63 ntfs_nthashinit(void)
     64 {
     65 	mutex_init(&ntfs_hashlock, MUTEX_DEFAULT, IPL_NONE);
     66 	mutex_init(&ntfs_nthash_lock, MUTEX_DEFAULT, IPL_NONE);
     67 	ntfs_nthashtbl = hashinit(desiredvnodes, HASH_LIST, true, &ntfs_nthash);
     68 }
     69 
     70 /*
     71  * Reinitialize inode hash table.
     72  */
     73 
     74 void
     75 ntfs_nthashreinit(void)
     76 {
     77 	struct ntnode *ip;
     78 	struct nthashhead *oldhash, *hash;
     79 	u_long oldmask, mask, val;
     80 	int i;
     81 
     82 	hash = hashinit(desiredvnodes, HASH_LIST, true, &mask);
     83 
     84 	mutex_enter(&ntfs_nthash_lock);
     85 	oldhash = ntfs_nthashtbl;
     86 	oldmask = ntfs_nthash;
     87 	ntfs_nthashtbl = hash;
     88 	ntfs_nthash = mask;
     89 	for (i = 0; i <= oldmask; i++) {
     90 		while ((ip = LIST_FIRST(&oldhash[i])) != NULL) {
     91 			LIST_REMOVE(ip, i_hash);
     92 			val = NTNOHASH(ip->i_dev, ip->i_number);
     93 			LIST_INSERT_HEAD(&hash[val], ip, i_hash);
     94 		}
     95 	}
     96 	mutex_exit(&ntfs_nthash_lock);
     97 	hashdone(oldhash, HASH_LIST, oldmask);
     98 }
     99 
    100 /*
    101  * Free the inode hash table. Called from ntfs_done(), only needed
    102  * on NetBSD.
    103  */
    104 void
    105 ntfs_nthashdone(void)
    106 {
    107 	hashdone(ntfs_nthashtbl, HASH_LIST, ntfs_nthash);
    108 	mutex_destroy(&ntfs_hashlock);
    109 	mutex_destroy(&ntfs_nthash_lock);
    110 }
    111 
    112 /*
    113  * Use the device/inum pair to find the incore inode, and return a pointer
    114  * to it. If it is in core, return it, even if it is locked.
    115  */
    116 struct ntnode *
    117 ntfs_nthashlookup(dev_t dev, ino_t inum)
    118 {
    119 	struct ntnode *ip;
    120 	struct nthashhead *ipp;
    121 
    122 	mutex_enter(&ntfs_nthash_lock);
    123 	ipp = &ntfs_nthashtbl[NTNOHASH(dev, inum)];
    124 	LIST_FOREACH(ip, ipp, i_hash) {
    125 		if (inum == ip->i_number && dev == ip->i_dev)
    126 			break;
    127 	}
    128 	mutex_exit(&ntfs_nthash_lock);
    129 
    130 	return (ip);
    131 }
    132 
    133 /*
    134  * Insert the ntnode into the hash table.
    135  */
    136 void
    137 ntfs_nthashins(struct ntnode *ip)
    138 {
    139 	struct nthashhead *ipp;
    140 
    141 	mutex_enter(&ntfs_nthash_lock);
    142 	ipp = &ntfs_nthashtbl[NTNOHASH(ip->i_dev, ip->i_number)];
    143 	LIST_INSERT_HEAD(ipp, ip, i_hash);
    144 	ip->i_flag |= IN_HASHED;
    145 	mutex_exit(&ntfs_nthash_lock);
    146 }
    147 
    148 /*
    149  * Remove the inode from the hash table.
    150  */
    151 void
    152 ntfs_nthashrem(struct ntnode *ip)
    153 {
    154 	mutex_enter(&ntfs_nthash_lock);
    155 	if (ip->i_flag & IN_HASHED) {
    156 		ip->i_flag &= ~IN_HASHED;
    157 		LIST_REMOVE(ip, i_hash);
    158 	}
    159 	mutex_exit(&ntfs_nthash_lock);
    160 }
    161