14dd08fd15
locking flags when acquiring a vnode. The immediate purpose is to allow polling lock requests (LK_NOWAIT) needed by soft updates to avoid deadlock when enlisting other processes to help with the background cleanup. For the future it will allow the use of shared locks for read access to vnodes. This change touches a lot of files as it affects most filesystems within the system. It has been well tested on FFS, loopback, and CD-ROM filesystems. only lightly on the others, so if you find a problem there, please let me (mckusick@mckusick.com) know.
163 lines
4.5 KiB
C
163 lines
4.5 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/vnode.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <sys/mutex.h>
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#include <ufs/ufs/quota.h>
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#include <ufs/ufs/inode.h>
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#include <ufs/ufs/ufs_extern.h>
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static MALLOC_DEFINE(M_UFSIHASH, "UFS ihash", "UFS Inode hash tables");
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/*
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* Structures associated with inode cacheing.
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*/
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static LIST_HEAD(ihashhead, inode) *ihashtbl;
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static u_long ihash; /* size of hash table - 1 */
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#define INOHASH(device, inum) (&ihashtbl[(minor(device) + (inum)) & ihash])
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static struct mtx ufs_ihash_mtx;
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/*
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* Initialize inode hash table.
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*/
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void
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ufs_ihashinit()
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{
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ihashtbl = hashinit(desiredvnodes, M_UFSIHASH, &ihash);
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mtx_init(&ufs_ihash_mtx, "ufs ihash", MTX_DEF);
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}
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/*
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* Use the device/inum pair to find the incore inode, and return a pointer
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* to it. If it is in core, return it, even if it is locked.
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*/
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struct vnode *
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ufs_ihashlookup(dev, inum)
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dev_t dev;
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ino_t inum;
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{
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struct inode *ip;
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mtx_lock(&ufs_ihash_mtx);
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LIST_FOREACH(ip, INOHASH(dev, inum), i_hash)
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if (inum == ip->i_number && dev == ip->i_dev)
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break;
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mtx_unlock(&ufs_ihash_mtx);
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if (ip)
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return (ITOV(ip));
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return (NULLVP);
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}
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/*
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* Use the device/inum pair to find the incore inode, and return a pointer
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* to it. If it is in core, but locked, wait for it.
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*/
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int
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ufs_ihashget(dev, inum, flags, vpp)
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dev_t dev;
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ino_t inum;
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int flags;
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struct vnode **vpp;
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{
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struct thread *td = curthread; /* XXX */
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struct inode *ip;
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struct vnode *vp;
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int error;
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*vpp = NULL;
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loop:
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mtx_lock(&ufs_ihash_mtx);
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LIST_FOREACH(ip, INOHASH(dev, inum), i_hash) {
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if (inum == ip->i_number && dev == ip->i_dev) {
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vp = ITOV(ip);
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mtx_lock(&vp->v_interlock);
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mtx_unlock(&ufs_ihash_mtx);
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error = vget(vp, flags | LK_INTERLOCK, td);
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if (error == ENOENT)
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goto loop;
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if (error)
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return (error);
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*vpp = vp;
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return (0);
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}
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}
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mtx_unlock(&ufs_ihash_mtx);
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return (0);
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}
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/*
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* Insert the inode into the hash table, and return it locked.
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*/
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void
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ufs_ihashins(ip)
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struct inode *ip;
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{
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struct thread *td = curthread; /* XXX */
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struct ihashhead *ipp;
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/* lock the inode, then put it on the appropriate hash list */
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lockmgr(&ip->i_vnode->v_lock, LK_EXCLUSIVE, (struct mtx *)0, td);
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mtx_lock(&ufs_ihash_mtx);
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ipp = INOHASH(ip->i_dev, ip->i_number);
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LIST_INSERT_HEAD(ipp, ip, i_hash);
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ip->i_flag |= IN_HASHED;
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mtx_unlock(&ufs_ihash_mtx);
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}
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/*
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* Remove the inode from the hash table.
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*/
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void
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ufs_ihashrem(ip)
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struct inode *ip;
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{
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mtx_lock(&ufs_ihash_mtx);
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if (ip->i_flag & IN_HASHED) {
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ip->i_flag &= ~IN_HASHED;
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LIST_REMOVE(ip, i_hash);
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}
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mtx_unlock(&ufs_ihash_mtx);
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}
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