sys/fs/hfs/hfs_nhash.c

   1 /*      $NetBSD: hfs_nhash.c,v 1.8 2008/05/05 17:11:16 ad Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2005, 2007 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Yevgeny Binder.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32  /*
  33  * Copyright (c) 1982, 1986, 1989, 1991, 1993
  34  *      The Regents of the University of California.  All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 3. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61 #include <sys/cdefs.h>
  62 __KERNEL_RCSID(0, "$NetBSD: hfs_nhash.c,v 1.8 2008/05/05 17:11:16 ad Exp $");
  63
  64 #include <sys/param.h>
  65 #include <sys/systm.h>
  66 #include <sys/kernel.h>
  67 #include <sys/vmmeter.h>
  68 #include <sys/time.h>
  69 #include <sys/proc.h>
  70 #include <sys/vnode.h>
  71 #include <sys/file.h>
  72 #include <sys/stat.h>
  73 #include <sys/mount.h>
  74 #include <sys/namei.h>
  75 #include <sys/buf.h>
  76 #include <sys/dirent.h>
  77 #include <sys/msgbuf.h>
  78
  79 #include <fs/hfs/hfs.h>
  80
  81 LIST_HEAD(nhashhead, hfsnode) *nhashtbl;
  82 u_long  nhash;          /* size of hash table - 1 */
  83 #define HNOHASH(device, cnid, fork)     (((device) + (cnid) + (fork)) & nhash)
  84
  85 kmutex_t hfs_hashlock;
  86 kmutex_t hfs_nhash_lock;
  87
  88 /*
  89  * Initialize hfsnode hash table.
  90  */
  91 void
  92 hfs_nhashinit(void)
  93 {
  94
  95         nhashtbl = hashinit(desiredvnodes, HASH_LIST, true, &nhash);
  96         mutex_init(&hfs_nhash_lock, MUTEX_DEFAULT, IPL_NONE);
  97         mutex_init(&hfs_hashlock, MUTEX_DEFAULT, IPL_NONE);
  98 }
  99
 100 /*
 101  * Free hfsnode hash table.
 102  */
 103 void
 104 hfs_nhashdone(void)
 105 {
 106
 107         hashdone(nhashtbl, HASH_LIST, nhash);
 108         mutex_destroy(&hfs_nhash_lock);
 109         mutex_destroy(&hfs_hashlock);
 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, but locked, wait for it.
 115  */
 116 struct vnode *
 117 hfs_nhashget(dev_t dev, hfs_cnid_t cnid, uint8_t fork, int flags)
 118 {
 119         struct hfsnode *hp;
 120         struct nhashhead *hpp;
 121         struct vnode *vp;
 122
 123 loop:
 124         mutex_enter(&hfs_nhash_lock);
 125         hpp = &nhashtbl[HNOHASH(dev, cnid, fork)];
 126         LIST_FOREACH(hp, hpp, h_hash) {
 127                 if (cnid == hp->h_rec.u.cnid && dev == hp->h_dev) {
 128                         vp = HTOV(hp);
 129                         if (flags == 0) {
 130                                 mutex_exit(&hfs_nhash_lock);
 131                         } else {
 132                                 mutex_enter(&vp->v_interlock);
 133                                 mutex_exit(&hfs_nhash_lock);
 134                                 if (vget(vp, flags | LK_INTERLOCK))
 135                                         goto loop;
 136                         }
 137                         return vp;
 138                 }
 139         }
 140         mutex_exit(&hfs_nhash_lock);
 141         return NULL;
 142 }
 143
 144 /*
 145 * Insert the hfsnode into the hash table, and return it locked.
 146  */
 147 void
 148 hfs_nhashinsert(struct hfsnode *hp)
 149 {
 150         struct nhashhead *hpp;
 151
 152         /* lock the inode, then put it on the appropriate hash list */
 153         vlockmgr(&hp->h_vnode->v_lock, LK_EXCLUSIVE);
 154
 155         mutex_enter(&hfs_nhash_lock);
 156         hpp = &nhashtbl[HNOHASH(hp->h_dev, hp->h_rec.u.cnid, hp->h_fork)];
 157         LIST_INSERT_HEAD(hpp, hp, h_hash);
 158         mutex_exit(&hfs_nhash_lock);
 159 }
 160
 161 /*
 162  * Remove the inode from the hash table.
 163  */
 164 void
 165 hfs_nhashremove(struct hfsnode *hp)
 166 {
 167
 168         mutex_enter(&hfs_nhash_lock);
 169         LIST_REMOVE(hp, h_hash);
 170         mutex_exit(&hfs_nhash_lock);
 171 }