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ntfs_ihash.c revision 1.10 
      1 /*	$NetBSD: ntfs_ihash.c,v 1.10 2012/01/27 19:48:40 para 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 1.10 2012/01/27 19:48:40 para 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/proc.h>
     44 #include <sys/mount.h>
     45 #include <sys/mallocvar.h>
     46 
     47 #include <fs/ntfs/ntfs.h>
     48 #include <fs/ntfs/ntfs_inode.h>
     49 #include <fs/ntfs/ntfs_ihash.h>
     50 
     51 /*
     52  * Structures associated with inode cacheing.
     53  */
     54 static LIST_HEAD(nthashhead, ntnode) *ntfs_nthashtbl;
     55 static u_long	ntfs_nthash;		/* size of hash table - 1 */
     56 #define	NTNOHASH(device, inum)	((minor(device) + (inum)) & ntfs_nthash)
     57 static kmutex_t ntfs_nthash_lock;
     58 kmutex_t ntfs_hashlock;
     59 
     60 /*
     61  * Initialize inode hash table.
     62  */
     63 void
     64 ntfs_nthashinit(void)
     65 {
     66 	mutex_init(&ntfs_hashlock, MUTEX_DEFAULT, IPL_NONE);
     67 	mutex_init(&ntfs_nthash_lock, MUTEX_DEFAULT, IPL_NONE);
     68 	ntfs_nthashtbl = hashinit(desiredvnodes, HASH_LIST, true, &ntfs_nthash);
     69 }
     70 
     71 /*
     72  * Reinitialize inode hash table.
     73  */
     74 
     75 void
     76 ntfs_nthashreinit(void)
     77 {
     78 	struct ntnode *ip;
     79 	struct nthashhead *oldhash, *hash;
     80 	u_long oldmask, mask, val;
     81 	int i;
     82 
     83 	hash = hashinit(desiredvnodes, HASH_LIST, true, &mask);
     84 
     85 	mutex_enter(&ntfs_nthash_lock);
     86 	oldhash = ntfs_nthashtbl;
     87 	oldmask = ntfs_nthash;
     88 	ntfs_nthashtbl = hash;
     89 	ntfs_nthash = mask;
     90 	for (i = 0; i <= oldmask; i++) {
     91 		while ((ip = LIST_FIRST(&oldhash[i])) != NULL) {
     92 			LIST_REMOVE(ip, i_hash);
     93 			val = NTNOHASH(ip->i_dev, ip->i_number);
     94 			LIST_INSERT_HEAD(&hash[val], ip, i_hash);
     95 		}
     96 	}
     97 	mutex_exit(&ntfs_nthash_lock);
     98 	hashdone(oldhash, HASH_LIST, oldmask);
     99 }
    100 
    101 /*
    102  * Free the inode hash table. Called from ntfs_done(), only needed
    103  * on NetBSD.
    104  */
    105 void
    106 ntfs_nthashdone(void)
    107 {
    108 	hashdone(ntfs_nthashtbl, HASH_LIST, ntfs_nthash);
    109 	mutex_destroy(&ntfs_hashlock);
    110 	mutex_destroy(&ntfs_nthash_lock);
    111 }
    112 
    113 /*
    114  * Use the device/inum pair to find the incore inode, and return a pointer
    115  * to it. If it is in core, return it, even if it is locked.
    116  */
    117 struct ntnode *
    118 ntfs_nthashlookup(dev_t dev, ino_t inum)
    119 {
    120 	struct ntnode *ip;
    121 	struct nthashhead *ipp;
    122 
    123 	mutex_enter(&ntfs_nthash_lock);
    124 	ipp = &ntfs_nthashtbl[NTNOHASH(dev, inum)];
    125 	LIST_FOREACH(ip, ipp, i_hash) {
    126 		if (inum == ip->i_number && dev == ip->i_dev)
    127 			break;
    128 	}
    129 	mutex_exit(&ntfs_nthash_lock);
    130 
    131 	return (ip);
    132 }
    133 
    134 /*
    135  * Insert the ntnode into the hash table.
    136  */
    137 void
    138 ntfs_nthashins(struct ntnode *ip)
    139 {
    140 	struct nthashhead *ipp;
    141 
    142 	mutex_enter(&ntfs_nthash_lock);
    143 	ipp = &ntfs_nthashtbl[NTNOHASH(ip->i_dev, ip->i_number)];
    144 	LIST_INSERT_HEAD(ipp, ip, i_hash);
    145 	ip->i_flag |= IN_HASHED;
    146 	mutex_exit(&ntfs_nthash_lock);
    147 }
    148 
    149 /*
    150  * Remove the inode from the hash table.
    151  */
    152 void
    153 ntfs_nthashrem(struct ntnode *ip)
    154 {
    155 	mutex_enter(&ntfs_nthash_lock);
    156 	if (ip->i_flag & IN_HASHED) {
    157 		ip->i_flag &= ~IN_HASHED;
    158 		LIST_REMOVE(ip, i_hash);
    159 	}
    160 	mutex_exit(&ntfs_nthash_lock);
    161 }
    162