freebsd-dev/sys/gnu/ext2fs/ext2_ihash.c
Boris Popov 67e871664b Add a lock structure to vnode structure. Previously it was either allocated
separately (nfs, cd9660 etc) or keept as a first element of structure
referenced by v_data pointer(ffs). Such organization leads to known problems
with stacked filesystems.

From this point vop_no*lock*() functions maintain only interlock lock.
vop_std*lock*() functions maintain built-in v_lock structure using lockmgr().
vop_sharedlock() is compatible with vop_stdunlock(), but maintains a shared
lock on vnode.

If filesystem wishes to export lockmgr compatible lock, it can put an address
of this lock to v_vnlock field. This indicates that the upper filesystem
can take advantage of it and use single lock structure for entire (or part)
of stack of vnodes. This field shouldn't be examined or modified by VFS code
except for initialization purposes.

Reviewed in general by:	mckusick
2000-09-25 15:24:04 +00:00

160 lines
4.5 KiB
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
* $FreeBSD$
*/
#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 <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])
#ifndef NULL_SIMPLELOCKS
static struct simplelock ufs_ihash_slock;
#endif
/*
* Initialize inode hash table.
*/
void
ufs_ihashinit()
{
ihashtbl = hashinit(desiredvnodes, M_UFSIHASH, &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;
/* lock the inode, then put it on the appropriate hash list */
lockmgr(&ip->i_vnode->v_lock, LK_EXCLUSIVE, (struct simplelock *)0, p);
simple_lock(&ufs_ihash_slock);
ipp = INOHASH(ip->i_dev, ip->i_number);
LIST_INSERT_HEAD(ipp, ip, i_hash);
ip->i_flag |= IN_HASHED;
simple_unlock(&ufs_ihash_slock);
}
/*
* Remove the inode from the hash table.
*/
void
ufs_ihashrem(ip)
struct inode *ip;
{
simple_lock(&ufs_ihash_slock);
if (ip->i_flag & IN_HASHED) {
ip->i_flag &= ~IN_HASHED;
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);
}