NetBSD/sys/dev/vnd.c

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/* $NetBSD: vnd.c,v 1.18 1995/02/27 19:31:00 cgd Exp $ */
/*
* Copyright (c) 1988 University of Utah.
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* 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.
*
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* from: Utah $Hdr: vn.c 1.13 94/04/02$
*
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* @(#)vn.c 8.6 (Berkeley) 4/1/94
*/
/*
* Vnode disk driver.
*
* Block/character interface to a vnode. Allows one to treat a file
* as a disk (e.g. build a filesystem in it, mount it, etc.).
*
* NOTE 1: This uses the VOP_BMAP/VOP_STRATEGY interface to the vnode
* instead of a simple VOP_RDWR. We do this to avoid distorting the
* local buffer cache.
*
* NOTE 2: There is a security issue involved with this driver.
* Once mounted all access to the contents of the "mapped" file via
* the special file is controlled by the permissions on the special
* file, the protection of the mapped file is ignored (effectively,
* by using root credentials in all transactions).
*
* NOTE 3: Doesn't interact with leases, should it?
*/
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#include "vnd.h"
#if NVND > 0
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/dkstat.h>
#include <sys/buf.h>
#include <sys/malloc.h>
#include <sys/ioctl.h>
#include <sys/disklabel.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <miscfs/specfs/specdev.h>
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#include <dev/vndioctl.h>
#ifdef DEBUG
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int dovndcluster = 1;
int vnddebug = 0x00;
#define VDB_FOLLOW 0x01
#define VDB_INIT 0x02
#define VDB_IO 0x04
#endif
#define b_cylin b_resid
#define vndunit(x) DISKUNIT(x)
struct vndbuf {
struct buf vb_buf;
struct buf *vb_obp;
};
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#define getvndbuf() \
((struct vndbuf *)malloc(sizeof(struct vndbuf), M_DEVBUF, M_WAITOK))
#define putvndbuf(vbp) \
free((caddr_t)(vbp), M_DEVBUF)
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struct vnd_softc {
int sc_flags; /* flags */
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size_t sc_size; /* size of vnd */
struct vnode *sc_vp; /* vnode */
struct ucred *sc_cred; /* credentials */
int sc_maxactive; /* max # of active requests */
struct buf sc_tab; /* transfer queue */
};
/* sc_flags */
#define VNF_ALIVE 0x01
#define VNF_INITED 0x02
#if 0 /* if you need static allocation */
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struct vnd_softc vn_softc[NVND];
int numvnd = NVND;
#else
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struct vnd_softc *vnd_softc;
int numvnd;
#endif
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void vndclear __P((struct vnd_softc *));
void vndstart __P((struct vnd_softc *));
int vndsetcred __P((struct vnd_softc *, struct ucred *));
void vndthrottle __P((struct vnd_softc *, struct vnode *));
void
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vndattach(num)
int num;
{
char *mem;
register u_long size;
if (num <= 0)
return;
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size = num * sizeof(struct vnd_softc);
mem = malloc(size, M_DEVBUF, M_NOWAIT);
if (mem == NULL) {
printf("WARNING: no memory for vnode disks\n");
return;
}
bzero(mem, size);
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vnd_softc = (struct vnd_softc *)mem;
numvnd = num;
}
int
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vndopen(dev, flags, mode, p)
dev_t dev;
int flags, mode;
struct proc *p;
{
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int unit = vndunit(dev);
#ifdef DEBUG
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if (vnddebug & VDB_FOLLOW)
printf("vndopen(%x, %x, %x, %x)\n", dev, flags, mode, p);
#endif
if (unit >= numvnd)
return(ENXIO);
return(0);
}
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int
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vndclose(dev, flags, mode, p)
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dev_t dev;
int flags, mode;
struct proc *p;
{
#ifdef DEBUG
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if (vnddebug & VDB_FOLLOW)
printf("vndclose(%x, %x, %x, %x)\n", dev, flags, mode, p);
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#endif
return 0;
}
/*
* Break the request into bsize pieces and submit using VOP_BMAP/VOP_STRATEGY.
* Note that this driver can only be used for swapping over NFS on the hp
* since nfs_strategy on the vax cannot handle u-areas and page tables.
*/
void
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vndstrategy(bp)
register struct buf *bp;
{
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int unit = vndunit(bp->b_dev);
register struct vnd_softc *vnd = &vnd_softc[unit];
register struct vndbuf *nbp;
register int bn, bsize, resid;
register caddr_t addr;
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int sz, flags, error;
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extern void vndiodone();
#ifdef DEBUG
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if (vnddebug & VDB_FOLLOW)
printf("vndstrategy(%x): unit %d\n", bp, unit);
#endif
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if ((vnd->sc_flags & VNF_INITED) == 0) {
bp->b_error = ENXIO;
bp->b_flags |= B_ERROR;
biodone(bp);
return;
}
bn = bp->b_blkno;
sz = howmany(bp->b_bcount, DEV_BSIZE);
bp->b_resid = bp->b_bcount;
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if (bn < 0 || bn + sz > vnd->sc_size) {
if (bn != vnd->sc_size) {
bp->b_error = EINVAL;
bp->b_flags |= B_ERROR;
}
biodone(bp);
return;
}
bn = dbtob(bn);
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bsize = vnd->sc_vp->v_mount->mnt_stat.f_iosize;
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addr = bp->b_data;
flags = bp->b_flags | B_CALL;
for (resid = bp->b_resid; resid; resid -= sz) {
struct vnode *vp;
daddr_t nbn;
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int off, s, nra;
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nra = 0;
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error = VOP_BMAP(vnd->sc_vp, bn / bsize, &vp, &nbn, &nra);
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if (error == 0 && (long)nbn == -1)
error = EIO;
#ifdef DEBUG
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if (!dovndcluster)
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nra = 0;
#endif
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if (off = bn % bsize)
sz = bsize - off;
else
sz = (1 + nra) * bsize;
if (resid < sz)
sz = resid;
#ifdef DEBUG
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if (vnddebug & VDB_IO)
printf("vndstrategy: vp %x/%x bn %x/%x sz %x\n",
vnd->sc_vp, vp, bn, nbn, sz);
#endif
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nbp = getvndbuf();
nbp->vb_buf.b_flags = flags;
nbp->vb_buf.b_bcount = sz;
nbp->vb_buf.b_bufsize = bp->b_bufsize;
nbp->vb_buf.b_error = 0;
if (vp->v_type == VBLK || vp->v_type == VCHR)
nbp->vb_buf.b_dev = vp->v_rdev;
else
nbp->vb_buf.b_dev = NODEV;
nbp->vb_buf.b_data = addr;
nbp->vb_buf.b_blkno = nbn + btodb(off);
nbp->vb_buf.b_proc = bp->b_proc;
nbp->vb_buf.b_iodone = vndiodone;
nbp->vb_buf.b_vp = vp;
nbp->vb_buf.b_rcred = vnd->sc_cred; /* XXX crdup? */
nbp->vb_buf.b_wcred = vnd->sc_cred; /* XXX crdup? */
nbp->vb_buf.b_dirtyoff = bp->b_dirtyoff;
nbp->vb_buf.b_dirtyend = bp->b_dirtyend;
nbp->vb_buf.b_validoff = bp->b_validoff;
nbp->vb_buf.b_validend = bp->b_validend;
/* save a reference to the old buffer */
nbp->vb_obp = bp;
/*
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* If there was an error or a hole in the file...punt.
* Note that we deal with this after the nbp allocation.
* This ensures that we properly clean up any operations
* that we have already fired off.
*
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* XXX we could deal with holes here but it would be
* a hassle (in the write case).
*/
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if (error) {
nbp->vb_buf.b_error = error;
nbp->vb_buf.b_flags |= B_ERROR;
bp->b_resid -= (resid - sz);
biodone(&nbp->vb_buf);
return;
}
/*
* Just sort by block number
*/
nbp->vb_buf.b_cylin = nbp->vb_buf.b_blkno;
s = splbio();
disksort(&vnd->sc_tab, &nbp->vb_buf);
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if (vnd->sc_tab.b_active < vnd->sc_maxactive) {
vnd->sc_tab.b_active++;
vndstart(vnd);
}
splx(s);
bn += sz;
addr += sz;
}
}
/*
* Feed requests sequentially.
* We do it this way to keep from flooding NFS servers if we are connected
* to an NFS file. This places the burden on the client rather than the
* server.
*/
void
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vndstart(vnd)
register struct vnd_softc *vnd;
{
register struct buf *bp;
/*
* Dequeue now since lower level strategy routine might
* queue using same links
*/
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bp = vnd->sc_tab.b_actf;
vnd->sc_tab.b_actf = bp->b_actf;
#ifdef DEBUG
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if (vnddebug & VDB_IO)
printf("vndstart(%d): bp %x vp %x blkno %x addr %x cnt %x\n",
vnd-vnd_softc, bp, bp->b_vp, bp->b_blkno, bp->b_data,
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bp->b_bcount);
#endif
if ((bp->b_flags & B_READ) == 0)
bp->b_vp->v_numoutput++;
VOP_STRATEGY(bp);
}
void
vndiodone(vbp)
register struct vndbuf *vbp;
{
register struct buf *pbp = vbp->vb_obp;
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register struct vnd_softc *vnd = &vnd_softc[vndunit(pbp->b_dev)];
int s;
s = splbio();
#ifdef DEBUG
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if (vnddebug & VDB_IO)
printf("vndiodone(%d): vbp %x vp %x blkno %x addr %x cnt %x\n",
vnd-vnd_softc, vbp, vbp->vb_buf.b_vp, vbp->vb_buf.b_blkno,
vbp->vb_buf.b_data, vbp->vb_buf.b_bcount);
#endif
if (vbp->vb_buf.b_error) {
#ifdef DEBUG
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if (vnddebug & VDB_IO)
printf("vndiodone: vbp %x error %d\n", vbp,
vbp->vb_buf.b_error);
#endif
pbp->b_flags |= B_ERROR;
pbp->b_error = biowait(&vbp->vb_buf);
}
pbp->b_resid -= vbp->vb_buf.b_bcount;
putvndbuf(vbp);
if (pbp->b_resid == 0) {
#ifdef DEBUG
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if (vnddebug & VDB_IO)
printf("vndiodone: pbp %x iodone\n", pbp);
#endif
biodone(pbp);
}
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if (vnd->sc_tab.b_actf)
vndstart(vnd);
else
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vnd->sc_tab.b_active--;
splx(s);
}
/* ARGSUSED */
int
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vndioctl(dev, cmd, data, flag, p)
dev_t dev;
u_long cmd;
caddr_t data;
int flag;
struct proc *p;
{
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int unit = vndunit(dev);
register struct vnd_softc *vnd;
struct vnd_ioctl *vio;
struct vattr vattr;
struct nameidata nd;
int error;
#ifdef DEBUG
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if (vnddebug & VDB_FOLLOW)
printf("vndioctl(%x, %lx, %x, %x, %x): unit %d\n",
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dev, cmd, data, flag, p, unit);
#endif
error = suser(p->p_ucred, &p->p_acflag);
if (error)
return (error);
if (unit >= numvnd)
return (ENXIO);
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vnd = &vnd_softc[unit];
vio = (struct vnd_ioctl *)data;
switch (cmd) {
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case VNDIOCSET:
if (vnd->sc_flags & VNF_INITED)
return(EBUSY);
/*
* Always open for read and write.
* This is probably bogus, but it lets vn_open()
* weed out directories, sockets, etc. so we don't
* have to worry about them.
*/
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vnd_file, p);
if (error = vn_open(&nd, FREAD|FWRITE, 0))
return(error);
if (error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p)) {
VOP_UNLOCK(nd.ni_vp);
(void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p);
return(error);
}
VOP_UNLOCK(nd.ni_vp);
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vnd->sc_vp = nd.ni_vp;
vnd->sc_size = btodb(vattr.va_size); /* note truncation */
if (error = vndsetcred(vnd, p->p_ucred)) {
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(void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p);
return(error);
}
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vndthrottle(vnd, vnd->sc_vp);
vio->vnd_size = dbtob(vnd->sc_size);
vnd->sc_flags |= VNF_INITED;
#ifdef DEBUG
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if (vnddebug & VDB_INIT)
printf("vndioctl: SET vp %x size %x\n",
vnd->sc_vp, vnd->sc_size);
#endif
break;
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case VNDIOCCLR:
if ((vnd->sc_flags & VNF_INITED) == 0)
return(ENXIO);
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vndclear(vnd);
#ifdef DEBUG
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if (vnddebug & VDB_INIT)
printf("vndioctl: CLRed\n");
#endif
break;
default:
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return(ENOTTY);
}
return(0);
}
/*
* Duplicate the current processes' credentials. Since we are called only
* as the result of a SET ioctl and only root can do that, any future access
* to this "disk" is essentially as root. Note that credentials may change
* if some other uid can write directly to the mapped file (NFS).
*/
int
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vndsetcred(vnd, cred)
register struct vnd_softc *vnd;
struct ucred *cred;
{
struct uio auio;
struct iovec aiov;
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char *tmpbuf;
int error;
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vnd->sc_cred = crdup(cred);
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tmpbuf = malloc(DEV_BSIZE, M_TEMP, M_WAITOK);
/* XXX: Horrible kludge to establish credentials for NFS */
aiov.iov_base = tmpbuf;
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aiov.iov_len = min(DEV_BSIZE, dbtob(vnd->sc_size));
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = 0;
auio.uio_rw = UIO_READ;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_resid = aiov.iov_len;
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error = VOP_READ(vnd->sc_vp, &auio, 0, vnd->sc_cred);
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free(tmpbuf, M_TEMP);
return (error);
}
/*
* Set maxactive based on FS type
*/
void
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vndthrottle(vnd, vp)
register struct vnd_softc *vnd;
struct vnode *vp;
{
#ifdef NFSCLIENT
extern int (**nfsv2_vnodeop_p)();
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if (vp->v_op == nfsv2_vnodeop_p)
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vnd->sc_maxactive = 2;
else
#endif
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vnd->sc_maxactive = 8;
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if (vnd->sc_maxactive < 1)
vnd->sc_maxactive = 1;
}
void
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vndshutdown()
{
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register struct vnd_softc *vnd;
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for (vnd = &vnd_softc[0]; vnd < &vnd_softc[numvnd]; vnd++)
if (vnd->sc_flags & VNF_INITED)
vndclear(vnd);
}
void
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vndclear(vnd)
register struct vnd_softc *vnd;
{
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register struct vnode *vp = vnd->sc_vp;
struct proc *p = curproc; /* XXX */
#ifdef DEBUG
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if (vnddebug & VDB_FOLLOW)
printf("vndclear(%x): vp %x\n", vp);
#endif
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vnd->sc_flags &= ~VNF_INITED;
if (vp == (struct vnode *)0)
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panic("vndioctl: null vp");
(void) vn_close(vp, FREAD|FWRITE, vnd->sc_cred, p);
crfree(vnd->sc_cred);
vnd->sc_vp = (struct vnode *)0;
vnd->sc_cred = (struct ucred *)0;
vnd->sc_size = 0;
}
int
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vndsize(dev)
dev_t dev;
{
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int unit = vndunit(dev);
register struct vnd_softc *vnd = &vnd_softc[unit];
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if (unit >= numvnd || (vnd->sc_flags & VNF_INITED) == 0)
return(-1);
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return(vnd->sc_size);
}
int
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vnddump(dev)
dev_t dev;
{
return(ENXIO);
}
#endif