NetBSD/sys/dev/vnd.c

778 lines
18 KiB
C

/* $NetBSD: vnd.c,v 1.30 1996/10/13 01:37:08 christos 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.
*
* from: Utah $Hdr: vn.c 1.13 94/04/02$
*
* @(#)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?
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/buf.h>
#include <sys/malloc.h>
#include <sys/ioctl.h>
#include <sys/disklabel.h>
#include <sys/device.h>
#include <sys/disk.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <sys/conf.h>
#include <miscfs/specfs/specdev.h>
#include <dev/vndioctl.h>
#ifdef DEBUG
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;
};
#define getvndbuf() \
((struct vndbuf *)malloc(sizeof(struct vndbuf), M_DEVBUF, M_WAITOK))
#define putvndbuf(vbp) \
free((caddr_t)(vbp), M_DEVBUF)
struct vnd_softc {
int sc_flags; /* flags */
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 */
char sc_xname[8]; /* XXX external name */
struct disk sc_dkdev; /* generic disk device info */
};
/* sc_flags */
#define VNF_ALIVE 0x01
#define VNF_INITED 0x02
#define VNF_WANTED 0x40
#define VNF_LOCKED 0x80
struct vnd_softc *vnd_softc;
int numvnd = 0;
/* called by main() at boot time */
void vndattach __P((int));
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 vndiodone __P((struct buf *));
void vndshutdown __P((void));
static int vndlock __P((struct vnd_softc *));
static void vndunlock __P((struct vnd_softc *));
void
vndattach(num)
int num;
{
char *mem;
register u_long size;
if (num <= 0)
return;
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);
vnd_softc = (struct vnd_softc *)mem;
numvnd = num;
}
int
vndopen(dev, flags, mode, p)
dev_t dev;
int flags, mode;
struct proc *p;
{
int unit = vndunit(dev);
struct vnd_softc *sc;
int error = 0, part, pmask;
/*
* XXX Should support disklabels.
*/
#ifdef DEBUG
if (vnddebug & VDB_FOLLOW)
printf("vndopen(%x, %x, %x, %p)\n", dev, flags, mode, p);
#endif
if (unit >= numvnd)
return (ENXIO);
sc = &vnd_softc[unit];
if ((error = vndlock(sc)) != 0)
return (error);
part = DISKPART(dev);
pmask = (1 << part);
/* Prevent our unit from being unconfigured while open. */
switch (mode) {
case S_IFCHR:
sc->sc_dkdev.dk_copenmask |= pmask;
break;
case S_IFBLK:
sc->sc_dkdev.dk_bopenmask |= pmask;
break;
}
sc->sc_dkdev.dk_openmask =
sc->sc_dkdev.dk_copenmask | sc->sc_dkdev.dk_bopenmask;
vndunlock(sc);
return (0);
}
int
vndclose(dev, flags, mode, p)
dev_t dev;
int flags, mode;
struct proc *p;
{
int unit = vndunit(dev);
struct vnd_softc *sc;
int error = 0, part;
#ifdef DEBUG
if (vnddebug & VDB_FOLLOW)
printf("vndclose(%x, %x, %x, %p)\n", dev, flags, mode, p);
#endif
if (unit >= numvnd)
return (ENXIO);
sc = &vnd_softc[unit];
if ((error = vndlock(sc)) != 0)
return (error);
part = DISKPART(dev);
/* ...that much closer to allowing unconfiguration... */
switch (mode) {
case S_IFCHR:
sc->sc_dkdev.dk_copenmask &= ~(1 << part);
break;
case S_IFBLK:
sc->sc_dkdev.dk_bopenmask &= ~(1 << part);
break;
}
sc->sc_dkdev.dk_openmask =
sc->sc_dkdev.dk_copenmask | sc->sc_dkdev.dk_bopenmask;
vndunlock(sc);
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
vndstrategy(bp)
register struct buf *bp;
{
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;
int sz, flags, error;
#ifdef DEBUG
if (vnddebug & VDB_FOLLOW)
printf("vndstrategy(%p): unit %d\n", bp, unit);
#endif
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;
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);
bsize = vnd->sc_vp->v_mount->mnt_stat.f_iosize;
addr = bp->b_data;
flags = bp->b_flags | B_CALL;
for (resid = bp->b_resid; resid; resid -= sz) {
struct vnode *vp;
daddr_t nbn;
int off, s, nra;
nra = 0;
VOP_LOCK(vnd->sc_vp);
error = VOP_BMAP(vnd->sc_vp, bn / bsize, &vp, &nbn, &nra);
VOP_UNLOCK(vnd->sc_vp);
if (error == 0 && (long)nbn == -1)
error = EIO;
#ifdef DEBUG
if (!dovndcluster)
nra = 0;
#endif
if ((off = bn % bsize) != 0)
sz = bsize - off;
else
sz = (1 + nra) * bsize;
if (resid < sz)
sz = resid;
#ifdef DEBUG
if (vnddebug & VDB_IO)
printf("vndstrategy: vp %p/%p bn %x/%x sz %x\n",
vnd->sc_vp, vp, bn, nbn, sz);
#endif
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;
/*
* 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.
*
* XXX we could deal with holes here but it would be
* a hassle (in the write case).
*/
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);
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
vndstart(vnd)
register struct vnd_softc *vnd;
{
register struct buf *bp;
/*
* Dequeue now since lower level strategy routine might
* queue using same links
*/
bp = vnd->sc_tab.b_actf;
vnd->sc_tab.b_actf = bp->b_actf;
#ifdef DEBUG
if (vnddebug & VDB_IO)
printf("vndstart(%ld): bp %p vp %p blkno %x addr %p cnt %lx\n",
(long) (vnd-vnd_softc), bp, bp->b_vp, bp->b_blkno,
bp->b_data, bp->b_bcount);
#endif
/* Instrumentation. */
disk_busy(&vnd->sc_dkdev);
if ((bp->b_flags & B_READ) == 0)
bp->b_vp->v_numoutput++;
VOP_STRATEGY(bp);
}
void
vndiodone(bp)
struct buf *bp;
{
register struct vndbuf *vbp = (struct vndbuf *) bp;
register struct buf *pbp = vbp->vb_obp;
register struct vnd_softc *vnd = &vnd_softc[vndunit(pbp->b_dev)];
int s;
s = splbio();
#ifdef DEBUG
if (vnddebug & VDB_IO)
printf("vndiodone(%ld): vbp %p vp %p blkno %x addr %p cnt %lx\n",
(long) (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
if (vnddebug & VDB_IO)
printf("vndiodone: vbp %p 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);
disk_unbusy(&vnd->sc_dkdev, (pbp->b_bcount - pbp->b_resid));
if (pbp->b_resid == 0) {
#ifdef DEBUG
if (vnddebug & VDB_IO)
printf("vndiodone: pbp %p iodone\n", pbp);
#endif
biodone(pbp);
}
if (vnd->sc_tab.b_actf)
vndstart(vnd);
else
vnd->sc_tab.b_active--;
splx(s);
}
/* ARGSUSED */
int
vndread(dev, uio, flags)
dev_t dev;
struct uio *uio;
int flags;
{
int unit = vndunit(dev);
struct vnd_softc *sc;
#ifdef DEBUG
if (vnddebug & VDB_FOLLOW)
printf("vndread(%x, %p)\n", dev, uio);
#endif
if (unit >= numvnd)
return (ENXIO);
sc = &vnd_softc[unit];
if ((sc->sc_flags & VNF_INITED) == 0)
return (ENXIO);
return (physio(vndstrategy, NULL, dev, B_READ, minphys, uio));
}
/* ARGSUSED */
int
vndwrite(dev, uio, flags)
dev_t dev;
struct uio *uio;
int flags;
{
int unit = vndunit(dev);
struct vnd_softc *sc;
#ifdef DEBUG
if (vnddebug & VDB_FOLLOW)
printf("vndwrite(%x, %p)\n", dev, uio);
#endif
if (unit >= numvnd)
return (ENXIO);
sc = &vnd_softc[unit];
if ((sc->sc_flags & VNF_INITED) == 0)
return (ENXIO);
return (physio(vndstrategy, NULL, dev, B_WRITE, minphys, uio));
}
/* ARGSUSED */
int
vndioctl(dev, cmd, data, flag, p)
dev_t dev;
u_long cmd;
caddr_t data;
int flag;
struct proc *p;
{
int unit = vndunit(dev);
register struct vnd_softc *vnd;
struct vnd_ioctl *vio;
struct vattr vattr;
struct nameidata nd;
int error, part, pmask, s;
#ifdef DEBUG
if (vnddebug & VDB_FOLLOW)
printf("vndioctl(%x, %lx, %p, %x, %p): unit %d\n",
dev, cmd, data, flag, p, unit);
#endif
error = suser(p->p_ucred, &p->p_acflag);
if (error)
return (error);
if (unit >= numvnd)
return (ENXIO);
vnd = &vnd_softc[unit];
vio = (struct vnd_ioctl *)data;
switch (cmd) {
case VNDIOCSET:
if (vnd->sc_flags & VNF_INITED)
return (EBUSY);
if ((error = vndlock(vnd)) != 0)
return (error);
/*
* 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.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vnd_file, p);
if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
vndunlock(vnd);
return(error);
}
error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p);
if (error) {
VOP_UNLOCK(nd.ni_vp);
(void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p);
vndunlock(vnd);
return(error);
}
VOP_UNLOCK(nd.ni_vp);
vnd->sc_vp = nd.ni_vp;
vnd->sc_size = btodb(vattr.va_size); /* note truncation */
if ((error = vndsetcred(vnd, p->p_ucred)) != 0) {
(void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p);
vndunlock(vnd);
return(error);
}
vndthrottle(vnd, vnd->sc_vp);
vio->vnd_size = dbtob(vnd->sc_size);
vnd->sc_flags |= VNF_INITED;
#ifdef DEBUG
if (vnddebug & VDB_INIT)
printf("vndioctl: SET vp %p size %lx\n",
vnd->sc_vp, (unsigned long) vnd->sc_size);
#endif
/* Attach the disk. */
bzero(vnd->sc_xname, sizeof(vnd->sc_xname)); /* XXX */
sprintf(vnd->sc_xname, "vnd%d", unit); /* XXX */
vnd->sc_dkdev.dk_name = vnd->sc_xname;
disk_attach(&vnd->sc_dkdev);
vndunlock(vnd);
break;
case VNDIOCCLR:
if ((vnd->sc_flags & VNF_INITED) == 0)
return (ENXIO);
if ((error = vndlock(vnd)) != 0)
return (error);
/*
* Don't unconfigure if any other partitions are open
* or if both the character and block flavors of this
* partition are open.
*/
part = DISKPART(dev);
pmask = (1 << part);
if ((vnd->sc_dkdev.dk_openmask & ~pmask) ||
((vnd->sc_dkdev.dk_bopenmask & pmask) &&
(vnd->sc_dkdev.dk_copenmask & pmask))) {
vndunlock(vnd);
return (EBUSY);
}
vndclear(vnd);
#ifdef DEBUG
if (vnddebug & VDB_INIT)
printf("vndioctl: CLRed\n");
#endif
/* Detatch the disk. */
disk_detach(&vnd->sc_dkdev);
/* This must be atomic. */
s = splhigh();
vndunlock(vnd);
bzero(vnd, sizeof(struct vnd_softc));
splx(s);
break;
/*
* XXX Should support disklabels.
*/
default:
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
vndsetcred(vnd, cred)
register struct vnd_softc *vnd;
struct ucred *cred;
{
struct uio auio;
struct iovec aiov;
char *tmpbuf;
int error;
vnd->sc_cred = crdup(cred);
tmpbuf = malloc(DEV_BSIZE, M_TEMP, M_WAITOK);
/* XXX: Horrible kludge to establish credentials for NFS */
aiov.iov_base = tmpbuf;
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;
VOP_LOCK(vnd->sc_vp);
error = VOP_READ(vnd->sc_vp, &auio, 0, vnd->sc_cred);
VOP_UNLOCK(vnd->sc_vp);
free(tmpbuf, M_TEMP);
return (error);
}
/*
* Set maxactive based on FS type
*/
void
vndthrottle(vnd, vp)
register struct vnd_softc *vnd;
struct vnode *vp;
{
#ifdef NFSCLIENT
extern int (**nfsv2_vnodeop_p) __P((void *));
if (vp->v_op == nfsv2_vnodeop_p)
vnd->sc_maxactive = 2;
else
#endif
vnd->sc_maxactive = 8;
if (vnd->sc_maxactive < 1)
vnd->sc_maxactive = 1;
}
void
vndshutdown()
{
register struct vnd_softc *vnd;
for (vnd = &vnd_softc[0]; vnd < &vnd_softc[numvnd]; vnd++)
if (vnd->sc_flags & VNF_INITED)
vndclear(vnd);
}
void
vndclear(vnd)
register struct vnd_softc *vnd;
{
register struct vnode *vp = vnd->sc_vp;
struct proc *p = curproc; /* XXX */
#ifdef DEBUG
if (vnddebug & VDB_FOLLOW)
printf("vndclear(%p): vp %p\n", vnd, vp);
#endif
vnd->sc_flags &= ~VNF_INITED;
if (vp == (struct vnode *)0)
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
vndsize(dev)
dev_t dev;
{
int unit = vndunit(dev);
register struct vnd_softc *vnd = &vnd_softc[unit];
if (unit >= numvnd || (vnd->sc_flags & VNF_INITED) == 0)
return(-1);
return(vnd->sc_size);
}
int
vnddump(dev, blkno, va, size)
dev_t dev;
daddr_t blkno;
caddr_t va;
size_t size;
{
/* Not implemented. */
return ENXIO;
}
/*
* Wait interruptibly for an exclusive lock.
*
* XXX
* Several drivers do this; it should be abstracted and made MP-safe.
*/
static int
vndlock(sc)
struct vnd_softc *sc;
{
int error;
while ((sc->sc_flags & VNF_LOCKED) != 0) {
sc->sc_flags |= VNF_WANTED;
if ((error = tsleep(sc, PRIBIO | PCATCH, "vndlck", 0)) != 0)
return (error);
}
sc->sc_flags |= VNF_LOCKED;
return (0);
}
/*
* Unlock and wake up any waiters.
*/
static void
vndunlock(sc)
struct vnd_softc *sc;
{
sc->sc_flags &= ~VNF_LOCKED;
if ((sc->sc_flags & VNF_WANTED) != 0) {
sc->sc_flags &= ~VNF_WANTED;
wakeup(sc);
}
}