FreeBSD/Linux Kernel Cross Reference
sys/ufs/ufs/ufs_ihash.c

     /*
      * Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
      *      The Regents of the University of California.  All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/5.2/sys/ufs/ufs/ufs_ihash.c 120738 2003-10-04 14:03:28Z jeff $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/vnode.h>
    #include <sys/malloc.h>
    #include <sys/proc.h>
    #include <sys/mutex.h>
    #include <sys/mount.h>
    
    #include <ufs/ufs/quota.h>
    #include <ufs/ufs/inode.h>
    #include <ufs/ufs/ufs_extern.h>
    
    static MALLOC_DEFINE(M_UFSIHASH, "UFS ihash", "UFS Inode hash tables");
    /*
     * Structures associated with inode cacheing.
     */
    static LIST_HEAD(ihashhead, inode) *ihashtbl;
    static u_long   ihash;          /* size of hash table - 1 */
    #define INOHASH(device, inum)   (&ihashtbl[(minor(device) + (inum)) & ihash])
    static struct mtx ufs_ihash_mtx;
    
    /*
     * Initialize inode hash table.
     */
    void
    ufs_ihashinit()
    {
    
            ihashtbl = hashinit(desiredvnodes, M_UFSIHASH, &ihash);
            mtx_init(&ufs_ihash_mtx, "ufs ihash", NULL, MTX_DEF);
    }
    
    /*
     * Destroy the inode hash table.
     */
    void
    ufs_ihashuninit()
    {
    
            hashdestroy(ihashtbl, M_UFSIHASH, ihash);
            mtx_destroy(&ufs_ihash_mtx);
    }
    
    /*
     * Use the device/inum pair to find the incore inode, and return a pointer
     * to it. If it is in core, return it, even if it is locked.
     */
    struct vnode *
    ufs_ihashlookup(dev, inum)
            dev_t dev;
            ino_t inum;
    {
            struct inode *ip;
    
            mtx_lock(&ufs_ihash_mtx);
            LIST_FOREACH(ip, INOHASH(dev, inum), i_hash)
                    if (inum == ip->i_number && dev == ip->i_dev)
                            break;
            mtx_unlock(&ufs_ihash_mtx);
   
           if (ip)
                   return (ITOV(ip));
           return (NULLVP);
   }
   
   /*
    * Use the device/inum pair to find the incore inode, and return a pointer
    * to it. If it is in core, but locked, wait for it.
    */
   int
   ufs_ihashget(dev, inum, flags, vpp)
           dev_t dev;
           ino_t inum;
           int flags;
           struct vnode **vpp;
   {
           struct thread *td = curthread;  /* XXX */
           struct inode *ip;
           struct vnode *vp;
           int error;
   
           *vpp = NULL;
   loop:
           mtx_lock(&ufs_ihash_mtx);
           LIST_FOREACH(ip, INOHASH(dev, inum), i_hash) {
                   if (inum == ip->i_number && dev == ip->i_dev) {
                           vp = ITOV(ip);
                           VI_LOCK(vp);
                           mtx_unlock(&ufs_ihash_mtx);
                           error = vget(vp, flags | LK_INTERLOCK, td);
                           if (error == ENOENT)
                                   goto loop;
                           if (error)
                                   return (error);
                           *vpp = vp;
                           return (0);
                   }
           }
           mtx_unlock(&ufs_ihash_mtx);
           return (0);
   }
   
   /*
    * Check hash for duplicate of passed inode, and add if there is no one.
    * if there is a duplicate, vget() it and return to the caller.
    */
   int
   ufs_ihashins(ip, flags, ovpp)
           struct inode *ip;
           int flags;
           struct vnode **ovpp;
   {
           struct thread *td = curthread;          /* XXX */
           struct ihashhead *ipp;
           struct inode *oip;
           struct vnode *ovp;
           int error;
   
   loop:
           mtx_lock(&ufs_ihash_mtx);
           ipp = INOHASH(ip->i_dev, ip->i_number);
           LIST_FOREACH(oip, ipp, i_hash) {
                   if (ip->i_number == oip->i_number && ip->i_dev == oip->i_dev) {
                           ovp = ITOV(oip);
                           VI_LOCK(ovp);
                           mtx_unlock(&ufs_ihash_mtx);
                           error = vget(ovp, flags | LK_INTERLOCK, td);
                           if (error == ENOENT)
                                   goto loop;
                           if (error)
                                   return (error);
                           *ovpp = ovp;
                           return (0);
                   }
           }
           LIST_INSERT_HEAD(ipp, ip, i_hash);
           ip->i_flag |= IN_HASHED;
           mtx_unlock(&ufs_ihash_mtx);
           *ovpp = NULL;
           return (0);
   }
   
   /*
    * Remove the inode from the hash table.
    */
   void
   ufs_ihashrem(ip)
           struct inode *ip;
   {
           mtx_lock(&ufs_ihash_mtx);
           if (ip->i_flag & IN_HASHED) {
                   ip->i_flag &= ~IN_HASHED;
                   LIST_REMOVE(ip, i_hash);
           }
           mtx_unlock(&ufs_ihash_mtx);
   }

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