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d389ead74f
This fixes a witness lock violation for nfssvc returning with locks held. Submitted by: Jean-Luc Richier <Jean-Luc.Richier@imag.fr> PR: kern/27776
277 lines
8.0 KiB
C
277 lines
8.0 KiB
C
/*-
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* Copyright (c) 1997 Berkeley Software Design, Inc. 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. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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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* from BSDI nfs_lock.c,v 2.4 1998/12/14 23:49:56 jch Exp
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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/fcntl.h>
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#include <sys/kernel.h> /* for hz */
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/lockf.h> /* for hz */ /* Must come after sys/malloc.h */
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#include <sys/mbuf.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/socket.h>
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#include <sys/socket.h>
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#include <sys/unistd.h>
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#include <sys/vnode.h>
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#include <net/if.h>
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#include <nfs/rpcv2.h>
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#include <nfs/nfsproto.h>
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#include <nfs/nfs.h>
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#include <nfs/nfsmount.h>
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#include <nfs/nfsnode.h>
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#include <nfs/nfs_lock.h>
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#include <nfs/nlminfo.h>
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#define NFSOWNER_1ST_LEVEL_START 1 /* initial entries */
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#define NFSOWNER_2ND_LEVEL 256 /* some power of 2 */
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#define NFSOWNER(tbl, i) \
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(tbl)[(i) / NFSOWNER_2ND_LEVEL][(i) % NFSOWNER_2ND_LEVEL]
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/*
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* XXX
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* We have to let the process know if the call succeeded. I'm using an extra
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* field in the p_nlminfo field in the proc structure, as it is already for
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* lockd stuff.
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*/
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/*
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* nfs_advlock --
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* NFS advisory byte-level locks.
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*/
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int
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nfs_dolock(ap)
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struct vop_advlock_args /* {
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struct vnode *a_vp;
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caddr_t a_id;
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int a_op;
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struct flock *a_fl;
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int a_flags;
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} */ *ap;
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{
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LOCKD_MSG msg;
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struct nameidata nd;
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struct proc *p;
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uid_t saved_uid;
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struct vnode *vp, *wvp;
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int error, error1;
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struct flock *fl;
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int fmode, ioflg;
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p = curproc;
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vp = ap->a_vp;
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fl = ap->a_fl;
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/*
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* the NLM protocol doesn't allow the server to return an error
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* on ranges, so we do it. Note that we should be returning
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* EOVERFLOW in some cases, but we don't have it.
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*/
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if (fl->l_start < 0 || fl->l_len < 0 ||
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((fl->l_len != 0 &&
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(fl->l_start + fl->l_len - 1) < 0)))
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return (EINVAL);
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/*
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* Fill in the information structure.
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*/
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msg.lm_version = LOCKD_MSG_VERSION;
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msg.lm_msg_ident.pid = p->p_pid;
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/*
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* if there is no nfsowner table yet, allocate one.
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*/
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if (p->p_nlminfo == NULL) {
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MALLOC(p->p_nlminfo, struct nlminfo *,
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sizeof(struct nlminfo), M_LOCKF, M_WAITOK | M_ZERO);
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p->p_nlminfo->pid_start = p->p_stats->p_start;
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}
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msg.lm_msg_ident.pid_start = p->p_nlminfo->pid_start;
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msg.lm_msg_ident.msg_seq = ++(p->p_nlminfo->msg_seq);
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msg.lm_fl = *fl;
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msg.lm_wait = ap->a_flags & F_WAIT;
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msg.lm_getlk = ap->a_op == F_GETLK;
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/*
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* XXX -- I think this is wrong for anything other AF_INET.
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*/
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msg.lm_addr = *(VFSTONFS(vp->v_mount)->nm_nam);
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msg.lm_fh_len = NFS_ISV3(vp) ? VTONFS(vp)->n_fhsize : NFSX_V2FH;
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bcopy(VTONFS(vp)->n_fhp, msg.lm_fh, msg.lm_fh_len);
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msg.lm_nfsv3 = NFS_ISV3(vp);
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msg.lm_cred = *(p->p_ucred);
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/*
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* Open the lock fifo. If for any reason we don't find the fifo, it
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* means that the lock daemon isn't running. Translate any missing
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* file error message for the user, otherwise the application will
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* complain that the user's file is missing, which isn't the case.
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* Note that we use proc0's cred, so the fifo is opened as root.
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*/
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, _PATH_LCKFIFO, p);
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/*
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* XXX Hack to temporarily allow this process (regardless of it's creds)
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* to open the fifo we need to write to. vn_open() really should
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* take a ucred (and once it does, this code should be fixed to use
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* proc0's ucred.
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*/
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saved_uid = p->p_ucred->cr_uid;
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p->p_ucred->cr_uid = 0; /* temporarly run the vn_open as root */
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fmode = FFLAGS(O_WRONLY);
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error = vn_open(&nd, &fmode, 0);
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p->p_ucred->cr_uid = saved_uid;
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if (error != 0) {
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return (error == ENOENT ? EOPNOTSUPP : error);
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}
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wvp = nd.ni_vp;
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VOP_UNLOCK(wvp, 0, p); /* vn_open leaves it locked */
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ioflg = IO_UNIT;
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for (;;) {
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VOP_LEASE(wvp, p, proc0.p_ucred, LEASE_WRITE);
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error = vn_rdwr(UIO_WRITE, wvp, (caddr_t)&msg, sizeof(msg), 0,
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UIO_SYSSPACE, ioflg, proc0.p_ucred, NULL, p);
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if (error && (((ioflg & IO_NDELAY) == 0) || error != EAGAIN)) {
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break;
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}
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/*
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* If we're locking a file, wait for an answer. Unlocks succeed
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* immediately.
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*/
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if (fl->l_type == F_UNLCK)
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/*
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* XXX this isn't exactly correct. The client side
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* needs to continue sending it's unlock until
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* it gets a responce back.
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*/
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break;
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/*
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* retry after 20 seconds if we haven't gotten a responce yet.
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* This number was picked out of thin air... but is longer
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* then even a reasonably loaded system should take (at least
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* on a local network). XXX Probably should use a back-off
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* scheme.
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*/
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if ((error = tsleep((void *)p->p_nlminfo,
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PCATCH | PUSER, "lockd", 20*hz)) != 0) {
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if (error == EWOULDBLOCK) {
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/*
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* We timed out, so we rewrite the request
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* to the fifo, but only if it isn't already
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* full.
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*/
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ioflg |= IO_NDELAY;
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continue;
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}
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break;
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}
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if (msg.lm_getlk && p->p_nlminfo->retcode == 0) {
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if (p->p_nlminfo->set_getlk_pid) {
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fl->l_pid = p->p_nlminfo->getlk_pid;
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} else {
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fl->l_type = F_UNLCK;
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}
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}
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error = p->p_nlminfo->retcode;
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break;
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}
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if ((error1 = vn_close(wvp, FWRITE, proc0.p_ucred, p)) && error == 0)
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return (error1);
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return (error);
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}
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/*
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* nfslockdans --
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* NFS advisory byte-level locks answer from the lock daemon.
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*/
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int
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nfslockdans(p, ansp)
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struct proc *p;
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struct lockd_ans *ansp;
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{
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int error;
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/* Let root, or someone who once was root (lockd generally
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* switches to the daemon uid once it is done setting up) make
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* this call.
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*
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* XXX This authorization check is probably not right.
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*/
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if ((error = suser(p)) != 0 && p->p_ucred->cr_svuid != 0)
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return (error);
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/* the version should match, or we're out of sync */
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if (ansp->la_vers != LOCKD_ANS_VERSION)
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return (EINVAL);
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/* Find the process, set its return errno and wake it up. */
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if ((p = pfind(ansp->la_msg_ident.pid)) == NULL)
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return (ESRCH);
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/* verify the pid hasn't been reused (if we can), and it isn't waiting
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* for an answer from a more recent request. We return an EPIPE if
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* the match fails, because we've already used ESRCH above, and this
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* is sort of like writing on a pipe after the reader has closed it.
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*/
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if (p->p_nlminfo == NULL ||
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((ansp->la_msg_ident.msg_seq != -1) &&
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(timevalcmp(&p->p_nlminfo->pid_start,
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&ansp->la_msg_ident.pid_start, !=) ||
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p->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) {
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PROC_UNLOCK(p);
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return (EPIPE);
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}
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p->p_nlminfo->retcode = ansp->la_errno;
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p->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
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p->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
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(void)wakeup((void *)p->p_nlminfo);
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PROC_UNLOCK(p);
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return (0);
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}
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