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ntfs_ihash.c revision 1.5 
      1 /*	$NetBSD: ntfs_ihash.c,v 1.5 2007/02/27 16:11:51 ad 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 1.5 2007/02/27 16:11:51 ad 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/malloc.h>
     44 #include <sys/proc.h>
     45 #include <sys/mount.h>
     46 
     47 #include <fs/ntfs/ntfs.h>
     48 #include <fs/ntfs/ntfs_inode.h>
     49 #include <fs/ntfs/ntfs_ihash.h>
     50 
     51 MALLOC_DEFINE(M_NTFSNTHASH, "NTFS nthash", "NTFS ntnode hash tables");
     52 
     53 /*
     54  * Structures associated with inode cacheing.
     55  */
     56 static LIST_HEAD(nthashhead, ntnode) *ntfs_nthashtbl;
     57 static u_long	ntfs_nthash;		/* size of hash table - 1 */
     58 #define	NTNOHASH(device, inum)	((minor(device) + (inum)) & ntfs_nthash)
     59 static kmutex_t ntfs_nthash_lock;
     60 kmutex_t ntfs_hashlock;
     61 
     62 /*
     63  * Initialize inode hash table.
     64  */
     65 void
     66 ntfs_nthashinit()
     67 {
     68 	mutex_init(&ntfs_hashlock, MUTEX_DEFAULT, IPL_NONE);
     69 	mutex_init(&ntfs_nthash_lock, MUTEX_DEFAULT, IPL_NONE);
     70 	ntfs_nthashtbl = HASHINIT(desiredvnodes, M_NTFSNTHASH, M_WAITOK,
     71 	    &ntfs_nthash);
     72 }
     73 
     74 /*
     75  * Reinitialize inode hash table.
     76  */
     77 
     78 void
     79 ntfs_nthashreinit()
     80 {
     81 	struct ntnode *ip;
     82 	struct nthashhead *oldhash, *hash;
     83 	u_long oldmask, mask, val;
     84 	int i;
     85 
     86 	hash = HASHINIT(desiredvnodes, M_NTFSNTHASH, M_WAITOK, &mask);
     87 
     88 	mutex_enter(&ntfs_nthash_lock);
     89 	oldhash = ntfs_nthashtbl;
     90 	oldmask = ntfs_nthash;
     91 	ntfs_nthashtbl = hash;
     92 	ntfs_nthash = mask;
     93 	for (i = 0; i <= oldmask; i++) {
     94 		while ((ip = LIST_FIRST(&oldhash[i])) != NULL) {
     95 			LIST_REMOVE(ip, i_hash);
     96 			val = NTNOHASH(ip->i_dev, ip->i_number);
     97 			LIST_INSERT_HEAD(&hash[val], ip, i_hash);
     98 		}
     99 	}
    100 	mutex_exit(&ntfs_nthash_lock);
    101 	hashdone(oldhash, M_NTFSNTHASH);
    102 }
    103 
    104 /*
    105  * Free the inode hash table. Called from ntfs_done(), only needed
    106  * on NetBSD.
    107  */
    108 void
    109 ntfs_nthashdone()
    110 {
    111 	hashdone(ntfs_nthashtbl, M_NTFSNTHASH);
    112 	mutex_destroy(&ntfs_hashlock);
    113 	mutex_destroy(&ntfs_nthash_lock);
    114 }
    115 
    116 /*
    117  * Use the device/inum pair to find the incore inode, and return a pointer
    118  * to it. If it is in core, return it, even if it is locked.
    119  */
    120 struct ntnode *
    121 ntfs_nthashlookup(dev, inum)
    122 	dev_t dev;
    123 	ino_t inum;
    124 {
    125 	struct ntnode *ip;
    126 	struct nthashhead *ipp;
    127 
    128 	mutex_enter(&ntfs_nthash_lock);
    129 	ipp = &ntfs_nthashtbl[NTNOHASH(dev, inum)];
    130 	LIST_FOREACH(ip, ipp, i_hash) {
    131 		if (inum == ip->i_number && dev == ip->i_dev)
    132 			break;
    133 	}
    134 	mutex_exit(&ntfs_nthash_lock);
    135 
    136 	return (ip);
    137 }
    138 
    139 /*
    140  * Insert the ntnode into the hash table.
    141  */
    142 void
    143 ntfs_nthashins(ip)
    144 	struct ntnode *ip;
    145 {
    146 	struct nthashhead *ipp;
    147 
    148 	mutex_enter(&ntfs_nthash_lock);
    149 	ipp = &ntfs_nthashtbl[NTNOHASH(ip->i_dev, ip->i_number)];
    150 	LIST_INSERT_HEAD(ipp, ip, i_hash);
    151 	ip->i_flag |= IN_HASHED;
    152 	mutex_exit(&ntfs_nthash_lock);
    153 }
    154 
    155 /*
    156  * Remove the inode from the hash table.
    157  */
    158 void
    159 ntfs_nthashrem(ip)
    160 	struct ntnode *ip;
    161 {
    162 	mutex_enter(&ntfs_nthash_lock);
    163 	if (ip->i_flag & IN_HASHED) {
    164 		ip->i_flag &= ~IN_HASHED;
    165 		LIST_REMOVE(ip, i_hash);
    166 	}
    167 	mutex_exit(&ntfs_nthash_lock);
    168 }
    169