The vn driver from 4.4_lite

1 files changed, 550 insertions, 0 deletions

diff --git a/sys/dev/vn/vn.c b/sys/dev/vn/vn.c
new file mode 100644
index 0000000..63d0359
--- /dev/null
+++ b/sys/dev/vn/vn.c
@@ -0,0 +1,550 @@
+#define DEBUG 1
+/*
+ * 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 "vn.h"
+#if NVN > 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/mount.h>
+#include <sys/vnode.h>
+#include <sys/file.h>
+#include <sys/uio.h>
+
+#include <miscfs/specfs/specdev.h>
+
+#include <sys/vnioctl.h>
+
+#ifdef DEBUG
+int dovncluster = 1;
+int vndebug = 0x00;
+#define VDB_FOLLOW	0x01
+#define VDB_INIT	0x02
+#define VDB_IO		0x04
+#endif
+
+#define	vnunit(x)	(minor(x) >> 3)
+
+#define	getvnbuf()	\
+	((struct buf *)malloc(sizeof(struct buf), M_DEVBUF, M_WAITOK))
+
+#define putvnbuf(bp)	\
+	free((caddr_t)(bp), M_DEVBUF)
+
+struct vn_softc {
+	int		 sc_flags;	/* flags */
+	size_t		 sc_size;	/* size of vn */
+	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_INITED	0x01
+
+struct vn_softc **vn_softc;
+int numvnd;
+
+void	vnattach __P((int num));
+int	vnopen __P((dev_t dev, int flags, int mode, struct proc *p));
+void	vnstrategy __P((struct buf *bp));
+void	vnstart __P((struct vn_softc *vn));
+void	vniodone __P((struct buf *bp));
+int	vnread __P((dev_t dev, struct uio *uio, int flags, struct proc *p));
+int	vnwrite __P((dev_t dev, struct uio *uio, int flags, struct proc *p));
+int	vnioctl __P((dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p));
+int	vnsetcred __P((struct vn_softc *vn, struct ucred *cred));
+void	vnthrottle __P((struct vn_softc *vn, struct vnode *vp));
+void	vnshutdown __P((void));
+void	vnclear __P((struct vn_softc *vn));
+size_t	vnsize __P((dev_t dev));
+int	vndump __P((dev_t dev));
+
+int vnclose() {return 0;}
+
+int
+vnopen(dev_t dev, int flags, int mode, struct proc *p)
+{
+	int unit = vnunit(dev),size;
+	struct vn_softc **vscp, **old;
+
+#ifdef DEBUG
+	if (vndebug & VDB_FOLLOW)
+		printf("vnopen(%x, %x, %x, %x)\n", dev, flags, mode, p);
+#endif
+	if (unit >= numvnd) {
+		/*
+		 * We need to get more space for our config.  If you say
+		 * this is overkill, you're absolutely right.
+		 */
+		size = (unit+1) * (sizeof *vn_softc);
+		vscp = (struct vn_softc **) malloc(size, M_DEVBUF, M_WAITOK);
+		if (!vscp)
+			return(ENOMEM);
+	        bzero(vscp,size);
+		if (numvnd)
+			bcopy(vn_softc, vscp, numvnd * (sizeof *vn_softc));
+		numvnd = unit + 1;
+		old = vn_softc;
+		vn_softc = vscp;
+		if (old)
+			free(old, M_DEVBUF);
+	}
+	if (!vn_softc[unit]) {
+		vn_softc[unit] = (struct vn_softc *) 
+			malloc (sizeof **vn_softc, M_DEVBUF, M_WAITOK);
+		if (!vn_softc[unit])
+			return(ENOMEM);
+		bzero(vn_softc[unit], sizeof **vn_softc);
+	}
+	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
+vnstrategy(struct buf *bp)
+{
+	int unit = vnunit(bp->b_dev);
+	register struct vn_softc *vn = vn_softc[unit];
+	register struct buf *nbp;
+	register int bn, bsize, resid;
+	register caddr_t addr;
+	int sz, flags, error;
+
+#ifdef DEBUG
+	if (vndebug & VDB_FOLLOW)
+		printf("vnstrategy(%x): unit %d\n", bp, unit);
+#endif
+	if ((vn->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 > vn->sc_size) {
+		if (bn != vn->sc_size) {
+			bp->b_error = EINVAL;
+			bp->b_flags |= B_ERROR;
+		}
+		biodone(bp);
+		return;
+	}
+	bn = dbtob(bn);
+	bsize = vn->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;
+		error = VOP_BMAP(vn->sc_vp, bn / bsize, &vp, &nbn, &nra);
+		if (error == 0 && (long)nbn == -1)
+			error = EIO;
+#ifdef DEBUG
+		if (!dovncluster)
+			nra = 0;
+#endif
+
+		if (off = bn % bsize)
+			sz = bsize - off;
+		else
+			sz = (1 + nra) * bsize;
+		if (resid < sz)
+			sz = resid;
+#ifdef DEBUG
+		if (vndebug & VDB_IO)
+			printf("vnstrategy: vp %x/%x bn %x/%x sz %x\n",
+			       vn->sc_vp, vp, bn, nbn, sz);
+#endif
+
+		nbp = getvnbuf();
+		nbp->b_flags = flags;
+		nbp->b_bcount = sz;
+		nbp->b_bufsize = bp->b_bufsize;
+		nbp->b_error = 0;
+		if (vp->v_type == VBLK || vp->v_type == VCHR)
+			nbp->b_dev = vp->v_rdev;
+		else
+			nbp->b_dev = NODEV;
+		nbp->b_data = addr;
+		nbp->b_blkno = nbn + btodb(off);
+		nbp->b_proc = bp->b_proc;
+		nbp->b_iodone = vniodone;
+		nbp->b_vp = vp;
+		nbp->b_pfcent = (int) bp;	/* XXX */
+		nbp->b_rcred = vn->sc_cred;	/* XXX crdup? */
+		nbp->b_wcred = vn->sc_cred;	/* XXX crdup? */
+		nbp->b_dirtyoff = bp->b_dirtyoff;
+		nbp->b_dirtyend = bp->b_dirtyend;
+		nbp->b_validoff = bp->b_validoff;
+		nbp->b_validend = bp->b_validend;
+		/*
+		 * 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->b_error = error;
+			nbp->b_flags |= B_ERROR;
+			bp->b_resid -= (resid - sz);
+			biodone(nbp);
+			return;
+		}
+		/*
+		 * Just sort by block number
+		 */
+		nbp->b_resid = nbp->b_blkno;
+		s = splbio();
+		disksort(&vn->sc_tab, nbp);
+		if (vn->sc_tab.b_active < vn->sc_maxactive) {
+			vn->sc_tab.b_active++;
+			vnstart(vn);
+		}
+		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
+vnstart(struct vn_softc *vn)
+{
+	register struct buf *bp;
+
+	/*
+	 * Dequeue now since lower level strategy routine might
+	 * queue using same links
+	 */
+	bp = vn->sc_tab.b_actf;
+	vn->sc_tab.b_actf = bp->b_actf;
+#ifdef DEBUG
+	if (vndebug & VDB_IO)
+		printf("vnstart(%d): bp %x vp %x blkno %x addr %x cnt %x\n",
+		       0, bp, bp->b_vp, bp->b_blkno, bp->b_data,
+		       bp->b_bcount);
+#endif
+	if ((bp->b_flags & B_READ) == 0)
+		bp->b_vp->v_numoutput++;
+	VOP_STRATEGY(bp);
+}
+
+void
+vniodone(struct buf *bp)
+{
+	register struct buf *pbp = (struct buf *)bp->b_pfcent;	/* XXX */
+	register struct vn_softc *vn = vn_softc[vnunit(pbp->b_dev)];
+	int s;
+
+	s = splbio();
+#ifdef DEBUG
+	if (vndebug & VDB_IO)
+		printf("vniodone(%d): bp %x vp %x blkno %x addr %x cnt %x\n",
+		       0, bp, bp->b_vp, bp->b_blkno, bp->b_data,
+		       bp->b_bcount);
+#endif
+	if (bp->b_error) {
+#ifdef DEBUG
+		if (vndebug & VDB_IO)
+			printf("vniodone: bp %x error %d\n", bp, bp->b_error);
+#endif
+		pbp->b_flags |= B_ERROR;
+		pbp->b_error = biowait(bp);
+	}
+	pbp->b_resid -= bp->b_bcount;
+	putvnbuf(bp);
+	if (pbp->b_resid == 0) {
+#ifdef DEBUG
+		if (vndebug & VDB_IO)
+			printf("vniodone: pbp %x iodone\n", pbp);
+#endif
+		biodone(pbp);
+	}
+	if (vn->sc_tab.b_actf)
+		vnstart(vn);
+	else
+		vn->sc_tab.b_active--;
+	splx(s);
+}
+
+int
+vnread(dev_t dev, struct uio *uio, int flags, struct proc *p)
+{
+
+#ifdef DEBUG
+	if (vndebug & VDB_FOLLOW)
+		printf("vnread(%x, %x, %x, %x)\n", dev, uio, flags, p);
+#endif
+	return(physio(vnstrategy, NULL, dev, B_READ, minphys, uio));
+}
+
+int
+vnwrite(dev_t dev, struct uio *uio, int flags, struct proc *p)
+{
+
+#ifdef DEBUG
+	if (vndebug & VDB_FOLLOW)
+		printf("vnwrite(%x, %x, %x, %x)\n", dev, uio, flags, p);
+#endif
+	return(physio(vnstrategy, NULL, dev, B_WRITE, minphys, uio));
+}
+
+/* ARGSUSED */
+int
+vnioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
+{
+	int unit = vnunit(dev);
+	register struct vn_softc *vn;
+	struct vn_ioctl *vio;
+	struct vattr vattr;
+	struct nameidata nd;
+	int error;
+
+#ifdef DEBUG
+	if (vndebug & VDB_FOLLOW)
+		printf("vnioctl(%x, %x, %x, %x, %x): 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);
+
+	vn = vn_softc[unit];
+	vio = (struct vn_ioctl *)data;
+	switch (cmd) {
+
+	case VNIOCSET:
+		if (vn->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.
+		 */
+		NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vn_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);
+		vn->sc_vp = nd.ni_vp;
+		vn->sc_size = btodb(vattr.va_size);	/* note truncation */
+		if (error = vnsetcred(vn, p->p_ucred)) {
+			(void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p);
+			return(error);
+		}
+		vnthrottle(vn, vn->sc_vp);
+		vio->vn_size = dbtob(vn->sc_size);
+		vn->sc_flags |= VNF_INITED;
+#ifdef DEBUG
+		if (vndebug & VDB_INIT)
+			printf("vnioctl: SET vp %x size %x\n",
+			       vn->sc_vp, vn->sc_size);
+#endif
+		break;
+
+	case VNIOCCLR:
+		if ((vn->sc_flags & VNF_INITED) == 0)
+			return(ENXIO);
+		vnclear(vn);
+#ifdef DEBUG
+		if (vndebug & VDB_INIT)
+			printf("vnioctl: CLRed\n");
+#endif
+		break;
+
+	default:
+		return(ENXIO);
+	}
+	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 
+vnsetcred(struct vn_softc *vn, struct ucred *cred)
+{
+	struct uio auio;
+	struct iovec aiov;
+	char *tmpbuf;
+	int error;
+
+	vn->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(vn->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;
+	error = VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred);
+
+	free(tmpbuf, M_TEMP);
+	return (error);
+}
+
+/*
+ * Set maxactive based on FS type
+ */
+void
+vnthrottle(struct vn_softc *vn, struct vnode *vp)
+{
+#if 0
+	extern int (**nfsv2_vnodeop_p)();
+
+	if (vp->v_op == nfsv2_vnodeop_p)
+		vn->sc_maxactive = 2;
+	else
+#endif
+		vn->sc_maxactive = 8;
+
+	if (vn->sc_maxactive < 1)
+		vn->sc_maxactive = 1;
+}
+
+void
+vnshutdown()
+{
+	int i;
+
+	for (i = 0; i < numvnd; i++)
+		if (vn_softc[i] && vn_softc[i]->sc_flags & VNF_INITED)
+			vnclear(vn_softc[i]);
+}
+TEXT_SET(cleanup_set,vnshutdown);
+
+void
+vnclear(struct vn_softc *vn)
+{
+	register struct vnode *vp = vn->sc_vp;
+	struct proc *p = curproc;		/* XXX */
+
+#ifdef DEBUG
+	if (vndebug & VDB_FOLLOW)
+		printf("vnclear(%x): vp %x\n", vp);
+#endif
+	vn->sc_flags &= ~VNF_INITED;
+	if (vp == (struct vnode *)0)
+		panic("vnioctl: null vp");
+	(void) vn_close(vp, FREAD|FWRITE, vn->sc_cred, p);
+	crfree(vn->sc_cred);
+	vn->sc_vp = (struct vnode *)0;
+	vn->sc_cred = (struct ucred *)0;
+	vn->sc_size = 0;
+}
+
+size_t
+vnsize(dev_t dev)
+{
+	int unit = vnunit(dev);
+	register struct vn_softc *vn = vn_softc[unit];
+
+	if (unit >= numvnd || (vn->sc_flags & VNF_INITED) == 0)
+		return(-1);
+	return(vn->sc_size);
+}
+
+int
+vndump(dev_t dev)
+{
+	return(ENXIO);
+}
+#endif