[unix-history] / usr / src / sys / ufs / ufs / ufs_ihash.c

/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
*      The Regents of the University of California.  All rights reserved.
*
* %sccs.include.redist.c%
*
*      @(#)ufs_ihash.c 8.6 (Berkeley) %G%
*/

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/proc.h>

#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufs_extern.h>

/*
* Structures associated with inode cacheing.
*/
LIST_HEAD(ihashhead, inode) *ihashtbl;
u_long  ihash;          /* size of hash table - 1 */
#define INOHASH(device, inum)   (&ihashtbl[((device) + (inum)) & ihash])
struct simplelock ufs_ihash_slock;

/*
* Initialize inode hash table.
*/
void
ufs_ihashinit()
{

       ihashtbl = hashinit(desiredvnodes, M_UFSMNT, &ihash);
       simple_lock_init(&ufs_ihash_slock);
}

/*
* 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;

       simple_lock(&ufs_ihash_slock);
       for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next)
               if (inum == ip->i_number && dev == ip->i_dev)
                       break;
       simple_unlock(&ufs_ihash_slock);

       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.
*/
struct vnode *
ufs_ihashget(dev, inum)
       dev_t dev;
       ino_t inum;
{
       struct proc *p = curproc;       /* XXX */
       struct inode *ip;
       struct vnode *vp;

loop:
       simple_lock(&ufs_ihash_slock);
       for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next) {
               if (inum == ip->i_number && dev == ip->i_dev) {
                       vp = ITOV(ip);
                       simple_lock(&vp->v_interlock);
                       simple_unlock(&ufs_ihash_slock);
                       if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, p))
                               goto loop;
                       return (vp);
               }
       }
       simple_unlock(&ufs_ihash_slock);
       return (NULL);
}

/*
* Insert the inode into the hash table, and return it locked.
*/
void
ufs_ihashins(ip)
       struct inode *ip;
{
       struct proc *p = curproc;               /* XXX */
       struct ihashhead *ipp;

       simple_lock(&ufs_ihash_slock);
       ipp = INOHASH(ip->i_dev, ip->i_number);
       LIST_INSERT_HEAD(ipp, ip, i_hash);
       simple_unlock(&ufs_ihash_slock);

       lockmgr(&ip->i_lock, LK_EXCLUSIVE, (struct simplelock *)0, p);
}

/*
* Remove the inode from the hash table.
*/
void
ufs_ihashrem(ip)
       struct inode *ip;
{
       struct inode *iq;

       simple_lock(&ufs_ihash_slock);
       LIST_REMOVE(ip, i_hash);
#ifdef DIAGNOSTIC
       ip->i_hash.le_next = NULL;
       ip->i_hash.le_prev = NULL;
#endif
       simple_unlock(&ufs_ihash_slock);
}