2b6ec89863
the vnode operations vector for active vnodes is unsafe because it is not known whether deadfs or the original file system will be called. - Pass down LK_RETRY to the lock operation (hint for deadfs only). - Change deadfs lock operation to return ENOENT if LK_RETRY is unset. - Change all other lock operations to check for dead vnode once the vnode is locked and unlock and return ENOENT in this case. With these changes in place vnode lock operations will never succeed after vclean() has marked the vnode as VI_XLOCK and before vclean() has changed the operations vector. Adresses PR kern/37706 (Forced unmount of file systems is unsafe) Discussed on tech-kern. Welcome to 6.99.33
174 lines
5.5 KiB
C
174 lines
5.5 KiB
C
/* $NetBSD: hfs_nhash.c,v 1.13 2014/02/27 16:51:38 hannken Exp $ */
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/*-
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* Copyright (c) 2005, 2007 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Yevgeny Binder.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1982, 1986, 1989, 1991, 1993
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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. 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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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: hfs_nhash.c,v 1.13 2014/02/27 16:51:38 hannken Exp $");
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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/vmmeter.h>
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#include <sys/time.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/buf.h>
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#include <sys/dirent.h>
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#include <sys/msgbuf.h>
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#include <fs/hfs/hfs.h>
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LIST_HEAD(nhashhead, hfsnode) *nhashtbl;
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u_long nhash; /* size of hash table - 1 */
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#define HNOHASH(device, cnid, fork) (((device) + (cnid) + (fork)) & nhash)
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kmutex_t hfs_hashlock;
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kmutex_t hfs_nhash_lock;
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/*
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* Initialize hfsnode hash table.
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*/
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void
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hfs_nhashinit(void)
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{
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nhashtbl = hashinit(desiredvnodes, HASH_LIST, true, &nhash);
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mutex_init(&hfs_nhash_lock, MUTEX_DEFAULT, IPL_NONE);
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mutex_init(&hfs_hashlock, MUTEX_DEFAULT, IPL_NONE);
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}
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/*
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* Free hfsnode hash table.
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*/
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void
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hfs_nhashdone(void)
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{
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hashdone(nhashtbl, HASH_LIST, nhash);
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mutex_destroy(&hfs_nhash_lock);
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mutex_destroy(&hfs_hashlock);
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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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struct vnode *
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hfs_nhashget(dev_t dev, hfs_cnid_t cnid, uint8_t fork, int flags)
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{
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struct hfsnode *hp;
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struct nhashhead *hpp;
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struct vnode *vp;
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loop:
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mutex_enter(&hfs_nhash_lock);
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hpp = &nhashtbl[HNOHASH(dev, cnid, fork)];
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LIST_FOREACH(hp, hpp, h_hash) {
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if (cnid == hp->h_rec.u.cnid && dev == hp->h_dev) {
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vp = HTOV(hp);
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if (flags == 0) {
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mutex_exit(&hfs_nhash_lock);
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} else {
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mutex_enter(vp->v_interlock);
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mutex_exit(&hfs_nhash_lock);
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if (vget(vp, flags))
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goto loop;
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}
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return vp;
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}
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}
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mutex_exit(&hfs_nhash_lock);
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return NULL;
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}
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/*
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* Insert the hfsnode into the hash table, and return it locked.
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*/
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void
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hfs_nhashinsert(struct hfsnode *hp)
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{
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struct nhashhead *hpp;
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int error __diagused;
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/* lock the inode, then put it on the appropriate hash list */
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error = VOP_LOCK(HTOV(hp), LK_EXCLUSIVE);
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KASSERT(error == 0);
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mutex_enter(&hfs_nhash_lock);
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hpp = &nhashtbl[HNOHASH(hp->h_dev, hp->h_rec.u.cnid, hp->h_fork)];
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LIST_INSERT_HEAD(hpp, hp, h_hash);
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mutex_exit(&hfs_nhash_lock);
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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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hfs_nhashremove(struct hfsnode *hp)
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{
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mutex_enter(&hfs_nhash_lock);
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LIST_REMOVE(hp, h_hash);
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mutex_exit(&hfs_nhash_lock);
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}
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