freebsd-nq/sys/nfsclient/nfs_lock.c
Julian Elischer b40ce4165d KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after:    ha ha ha ha
2001-09-12 08:38:13 +00:00

287 lines
8.2 KiB
C

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