[unix-history] / usr / src / sys / miscfs / union / union_vfsops.c

/*
 * Copyright (c) 1994 The Regents of the University of California.
 * Copyright (c) 1994 Jan-Simon Pendry.
 * All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)union_vfsops.c	8.14 (Berkeley) %G%
 */

/*
 * Union Layer
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/filedesc.h>
#include <sys/queue.h>
#include <miscfs/union/union.h>

/*
 * Mount union filesystem
 */
int
union_mount(mp, path, data, ndp, p)
	struct mount *mp;
	char *path;
	caddr_t data;
	struct nameidata *ndp;
	struct proc *p;
{
	int error = 0;
	struct union_args args;
	struct vnode *lowerrootvp = NULLVP;
	struct vnode *upperrootvp = NULLVP;
	struct union_mount *um = 0;
	struct ucred *cred = 0;
	struct ucred *scred;
	struct vattr va;
	char *cp;
	int len;
	u_int size;

#ifdef UNION_DIAGNOSTIC
	printf("union_mount(mp = %x)\n", mp);
#endif

	/*
	 * Update is a no-op
	 */
	if (mp->mnt_flag & MNT_UPDATE) {
		/*
		 * Need to provide.
		 * 1. a way to convert between rdonly and rdwr mounts.
		 * 2. support for nfs exports.
		 */
		error = EOPNOTSUPP;
		goto bad;
	}

	/*
	 * Get argument
	 */
	if (error = copyin(data, (caddr_t)&args, sizeof(struct union_args)))
		goto bad;

	lowerrootvp = mp->mnt_vnodecovered;
	VREF(lowerrootvp);

	/*
	 * Find upper node.
	 */
	NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT,
	       UIO_USERSPACE, args.target, p);

	if (error = namei(ndp))
		goto bad;

	upperrootvp = ndp->ni_vp;
	vrele(ndp->ni_dvp);
	ndp->ni_dvp = NULL;

	if (upperrootvp->v_type != VDIR) {
		error = EINVAL;
		goto bad;
	}
	
	um = (struct union_mount *) malloc(sizeof(struct union_mount),
				M_UFSMNT, M_WAITOK);	/* XXX */

	/*
	 * Keep a held reference to the target vnodes.
	 * They are vrele'd in union_unmount.
	 *
	 * Depending on the _BELOW flag, the filesystems are
	 * viewed in a different order.  In effect, this is the
	 * same as providing a mount under option to the mount syscall.
	 */

	um->um_op = args.mntflags & UNMNT_OPMASK;
	switch (um->um_op) {
	case UNMNT_ABOVE:
		um->um_lowervp = lowerrootvp;
		um->um_uppervp = upperrootvp;
		break;

	case UNMNT_BELOW:
		um->um_lowervp = upperrootvp;
		um->um_uppervp = lowerrootvp;
		break;

	case UNMNT_REPLACE:
		vrele(lowerrootvp);
		lowerrootvp = NULLVP;
		um->um_uppervp = upperrootvp;
		um->um_lowervp = lowerrootvp;
		break;

	default:
		error = EINVAL;
		goto bad;
	}

	/*
	 * Unless the mount is readonly, ensure that the top layer
	 * supports whiteout operations
	 */
	if ((mp->mnt_flag & MNT_RDONLY) == 0) {
		error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP);
		if (error)
			goto bad;
	}

	um->um_cred = p->p_ucred;
	crhold(um->um_cred);
	um->um_cmode = UN_DIRMODE &~ p->p_fd->fd_cmask;

	/*
	 * Depending on what you think the MNT_LOCAL flag might mean,
	 * you may want the && to be || on the conditional below.
	 * At the moment it has been defined that the filesystem is
	 * only local if it is all local, ie the MNT_LOCAL flag implies
	 * that the entire namespace is local.  If you think the MNT_LOCAL
	 * flag implies that some of the files might be stored locally
	 * then you will want to change the conditional.
	 */
	if (um->um_op == UNMNT_ABOVE) {
		if (((um->um_lowervp == NULLVP) ||
		     (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
		    (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
			mp->mnt_flag |= MNT_LOCAL;
	}

	/*
	 * Copy in the upper layer's RDONLY flag.  This is for the benefit
	 * of lookup() which explicitly checks the flag, rather than asking
	 * the filesystem for it's own opinion.  This means, that an update
	 * mount of the underlying filesystem to go from rdonly to rdwr
	 * will leave the unioned view as read-only.
	 */
	mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);

	mp->mnt_data = (qaddr_t) um;
	getnewfsid(mp, MOUNT_UNION);

	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);

	switch (um->um_op) {
	case UNMNT_ABOVE:
		cp = "<above>:";
		break;
	case UNMNT_BELOW:
		cp = "<below>:";
		break;
	case UNMNT_REPLACE:
		cp = "";
		break;
	}
	len = strlen(cp);
	bcopy(cp, mp->mnt_stat.f_mntfromname, len);

	cp = mp->mnt_stat.f_mntfromname + len;
	len = MNAMELEN - len;

	(void) copyinstr(args.target, cp, len - 1, &size);
	bzero(cp + size, len - size);

#ifdef UNION_DIAGNOSTIC
	printf("union_mount: from %s, on %s\n",
		mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
#endif
	return (0);

bad:
	if (um)
		free(um, M_UFSMNT);
	if (cred)
		crfree(cred);
	if (upperrootvp)
		vrele(upperrootvp);
	if (lowerrootvp)
		vrele(lowerrootvp);
	return (error);
}

/*
 * VFS start.  Nothing needed here - the start routine
 * on the underlying filesystem(s) will have been called
 * when that filesystem was mounted.
 */
int
union_start(mp, flags, p)
	struct mount *mp;
	int flags;
	struct proc *p;
{

	return (0);
}

/*
 * Free reference to union layer
 */
int
union_unmount(mp, mntflags, p)
	struct mount *mp;
	int mntflags;
	struct proc *p;
{
	struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
	struct vnode *um_rootvp;
	int error;
	int freeing;
	int flags = 0;
	extern int doforce;

#ifdef UNION_DIAGNOSTIC
	printf("union_unmount(mp = %x)\n", mp);
#endif

	if (mntflags & MNT_FORCE) {
		/* union can never be rootfs so don't check for it */
		if (!doforce)
			return (EINVAL);
		flags |= FORCECLOSE;
	}

	if (error = union_root(mp, &um_rootvp))
		return (error);

	/*
	 * Keep flushing vnodes from the mount list.
	 * This is needed because of the un_pvp held
	 * reference to the parent vnode.
	 * If more vnodes have been freed on a given pass,
	 * the try again.  The loop will iterate at most
	 * (d) times, where (d) is the maximum tree depth
	 * in the filesystem.
	 */
	for (freeing = 0; vflush(mp, um_rootvp, flags) != 0;) {
		struct vnode *vp;
		int n;

		/* count #vnodes held on mount list */
		for (n = 0, vp = mp->mnt_vnodelist.lh_first;
				vp != NULLVP;
				vp = vp->v_mntvnodes.le_next)
			n++;

		/* if this is unchanged then stop */
		if (n == freeing)
			break;

		/* otherwise try once more time */
		freeing = n;
	}

	/* At this point the root vnode should have a single reference */
	if (um_rootvp->v_usecount > 1) {
		vput(um_rootvp);
		return (EBUSY);
	}

#ifdef UNION_DIAGNOSTIC
	vprint("union root", um_rootvp);
#endif	 
	/*
	 * Discard references to upper and lower target vnodes.
	 */
	if (um->um_lowervp)
		vrele(um->um_lowervp);
	vrele(um->um_uppervp);
	crfree(um->um_cred);
	/*
	 * Release reference on underlying root vnode
	 */
	vput(um_rootvp);
	/*
	 * And blow it away for future re-use
	 */
	vgone(um_rootvp);
	/*
	 * Finally, throw away the union_mount structure
	 */
	free(mp->mnt_data, M_UFSMNT);	/* XXX */
	mp->mnt_data = 0;
	return (0);
}

int
union_root(mp, vpp)
	struct mount *mp;
	struct vnode **vpp;
{
	struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
	int error;
	int loselock;

	/*
	 * Return locked reference to root.
	 */
	VREF(um->um_uppervp);
	if ((um->um_op == UNMNT_BELOW) &&
	     VOP_ISLOCKED(um->um_uppervp)) {
		loselock = 1;
	} else {
		VOP_LOCK(um->um_uppervp);
		loselock = 0;
	}
	if (um->um_lowervp)
		VREF(um->um_lowervp);
	error = union_allocvp(vpp, mp,
			      (struct vnode *) 0,
			      (struct vnode *) 0,
			      (struct componentname *) 0,
			      um->um_uppervp,
			      um->um_lowervp,
			      1);

	if (error) {
		if (!loselock)
			VOP_UNLOCK(um->um_uppervp);
		vrele(um->um_uppervp);
		if (um->um_lowervp)
			vrele(um->um_lowervp);
	} else {
		if (loselock)
			VTOUNION(*vpp)->un_flags &= ~UN_ULOCK;
	}

	return (error);
}

int
union_quotactl(mp, cmd, uid, arg, p)
	struct mount *mp;
	int cmd;
	uid_t uid;
	caddr_t arg;
	struct proc *p;
{

	return (EOPNOTSUPP);
}

int
union_statfs(mp, sbp, p)
	struct mount *mp;
	struct statfs *sbp;
	struct proc *p;
{
	int error;
	struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
	struct statfs mstat;
	int lbsize;

#ifdef UNION_DIAGNOSTIC
	printf("union_statfs(mp = %x, lvp = %x, uvp = %x)\n", mp,
			um->um_lowervp,
	       		um->um_uppervp);
#endif

	bzero(&mstat, sizeof(mstat));

	if (um->um_lowervp) {
		error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p);
		if (error)
			return (error);
	}

	/* now copy across the "interesting" information and fake the rest */
#if 0
	sbp->f_type = mstat.f_type;
	sbp->f_flags = mstat.f_flags;
	sbp->f_bsize = mstat.f_bsize;
	sbp->f_iosize = mstat.f_iosize;
#endif
	lbsize = mstat.f_bsize;
	sbp->f_blocks = mstat.f_blocks;
	sbp->f_bfree = mstat.f_bfree;
	sbp->f_bavail = mstat.f_bavail;
	sbp->f_files = mstat.f_files;
	sbp->f_ffree = mstat.f_ffree;

	error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p);
	if (error)
		return (error);

	sbp->f_type = MOUNT_UNION;
	sbp->f_flags = mstat.f_flags;
	sbp->f_bsize = mstat.f_bsize;
	sbp->f_iosize = mstat.f_iosize;

	/*
	 * if the lower and upper blocksizes differ, then frig the
	 * block counts so that the sizes reported by df make some
	 * kind of sense.  none of this makes sense though.
	 */

	if (mstat.f_bsize != lbsize)
		sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize;

	/*
	 * The "total" fields count total resources in all layers,
	 * the "free" fields count only those resources which are
	 * free in the upper layer (since only the upper layer
	 * is writeable).
	 */
	sbp->f_blocks += mstat.f_blocks;
	sbp->f_bfree = mstat.f_bfree;
	sbp->f_bavail = mstat.f_bavail;
	sbp->f_files += mstat.f_files;
	sbp->f_ffree = mstat.f_ffree;

	if (sbp != &mp->mnt_stat) {
		bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
	}
	return (0);
}

int
union_sync(mp, waitfor, cred, p)
	struct mount *mp;
	int waitfor;
	struct ucred *cred;
	struct proc *p;
{

	/*
	 * XXX - Assumes no data cached at union layer.
	 */
	return (0);
}

int
union_vget(mp, ino, vpp)
	struct mount *mp;
	ino_t ino;
	struct vnode **vpp;
{
	
	return (EOPNOTSUPP);
}

int
union_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
	struct mount *mp;
	struct fid *fidp;
	struct mbuf *nam;
	struct vnode **vpp;
	int *exflagsp;
	struct ucred **credanonp;
{

	return (EOPNOTSUPP);
}

int
union_vptofh(vp, fhp)
	struct vnode *vp;
	struct fid *fhp;
{

	return (EOPNOTSUPP);
}

int union_init __P((void));

struct vfsops union_vfsops = {
	union_mount,
	union_start,
	union_unmount,
	union_root,
	union_quotactl,
	union_statfs,
	union_sync,
	union_vget,
	union_fhtovp,
	union_vptofh,
	union_init,
};
Commit	Line	Data
a1fa407d JSP	1	/*
	2	* Copyright (c) 1994 The Regents of the University of California.
	3	* Copyright (c) 1994 Jan-Simon Pendry.
	4	* All rights reserved.
	5	*
	6	* This code is derived from software donated to Berkeley by
	7	* Jan-Simon Pendry.
	8	*
	9	* %sccs.include.redist.c%
	10	*
8583490d	11	* @(#)union_vfsops.c 8.14 (Berkeley) %G%
a1fa407d JSP	12	*/
	13
	14	/*
81be6ee0	15	* Union Layer
a1fa407d JSP	16	*/
	17
	18	#include <sys/param.h>
	19	#include <sys/systm.h>
	20	#include <sys/time.h>
	21	#include <sys/types.h>
	22	#include <sys/proc.h>
	23	#include <sys/vnode.h>
	24	#include <sys/mount.h>
	25	#include <sys/namei.h>
	26	#include <sys/malloc.h>
3b293975	27	#include <sys/filedesc.h>
58572fc0	28	#include <sys/queue.h>
2e1ae99e	29	#include <miscfs/union/union.h>
a1fa407d JSP	30
	31	/*
	32	* Mount union filesystem
	33	*/
	34	int
	35	union_mount(mp, path, data, ndp, p)
	36	struct mount *mp;
	37	char *path;
	38	caddr_t data;
	39	struct nameidata *ndp;
	40	struct proc *p;
	41	{
	42	int error = 0;
	43	struct union_args args;
692a90df JSP	44	struct vnode *lowerrootvp = NULLVP;
692a90df JSP	45	struct vnode *upperrootvp = NULLVP;
88edbcd4	46	struct union_mount *um = 0;
692a90df	47	struct ucred *cred = 0;
9f7857db	48	struct ucred *scred;
c1b204a8	49	struct vattr va;
692a90df JSP	50	char *cp;
692a90df JSP	51	int len;
a1fa407d JSP	52	u_int size;
	53
	54	#ifdef UNION_DIAGNOSTIC
	55	printf("union_mount(mp = %x)\n", mp);
	56	#endif
	57
	58	/*
	59	* Update is a no-op
	60	*/
81be6ee0 JSP	61	if (mp->mnt_flag & MNT_UPDATE) {
	62	/*
	63	* Need to provide.
	64	* 1. a way to convert between rdonly and rdwr mounts.
	65	* 2. support for nfs exports.
	66	*/
692a90df JSP	67	error = EOPNOTSUPP;
692a90df JSP	68	goto bad;
81be6ee0	69	}
a1fa407d JSP	70
	71	/*
	72	* Get argument
	73	*/
	74	if (error = copyin(data, (caddr_t)&args, sizeof(struct union_args)))
692a90df	75	goto bad;
a1fa407d JSP	76
	77	lowerrootvp = mp->mnt_vnodecovered;
	78	VREF(lowerrootvp);
	79
	80	/*
88edbcd4	81	* Find upper node.
a1fa407d JSP	82	*/
	83	NDINIT(ndp, LOOKUP, FOLLOW\|WANTPARENT,
	84	UIO_USERSPACE, args.target, p);
9f7857db	85
692a90df JSP	86	if (error = namei(ndp))
	87	goto bad;
	88
a1fa407d JSP	89	upperrootvp = ndp->ni_vp;
	90	vrele(ndp->ni_dvp);
	91	ndp->ni_dvp = NULL;
	92
	93	if (upperrootvp->v_type != VDIR) {
692a90df JSP	94	error = EINVAL;
692a90df JSP	95	goto bad;
a1fa407d JSP	96	}
	97
	98	um = (struct union_mount *) malloc(sizeof(struct union_mount),
	99	M_UFSMNT, M_WAITOK); /* XXX */
	100
	101	/*
	102	* Keep a held reference to the target vnodes.
	103	* They are vrele'd in union_unmount.
692a90df JSP	104	*
	105	* Depending on the _BELOW flag, the filesystems are
	106	* viewed in a different order. In effect, this is the
	107	* same as providing a mount under option to the mount syscall.
a1fa407d	108	*/
692a90df	109
c1b204a8 JSP	110	um->um_op = args.mntflags & UNMNT_OPMASK;
c1b204a8 JSP	111	switch (um->um_op) {
692a90df JSP	112	case UNMNT_ABOVE:
	113	um->um_lowervp = lowerrootvp;
	114	um->um_uppervp = upperrootvp;
	115	break;
	116
	117	case UNMNT_BELOW:
	118	um->um_lowervp = upperrootvp;
	119	um->um_uppervp = lowerrootvp;
	120	break;
	121
	122	case UNMNT_REPLACE:
	123	vrele(lowerrootvp);
	124	lowerrootvp = NULLVP;
	125	um->um_uppervp = upperrootvp;
	126	um->um_lowervp = lowerrootvp;
	127	break;
	128
	129	default:
	130	error = EINVAL;
	131	goto bad;
	132	}
	133
88edbcd4 JSP	134	/*
	135	* Unless the mount is readonly, ensure that the top layer
	136	* supports whiteout operations
	137	*/
	138	if ((mp->mnt_flag & MNT_RDONLY) == 0) {
	139	error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP);
	140	if (error)
	141	goto bad;
	142	}
	143
	144	um->um_cred = p->p_ucred;
	145	crhold(um->um_cred);
3b293975	146	um->um_cmode = UN_DIRMODE &~ p->p_fd->fd_cmask;
a1fa407d	147
3b293975 JSP	148	/*
	149	* Depending on what you think the MNT_LOCAL flag might mean,
	150	* you may want the && to be \|\| on the conditional below.
	151	* At the moment it has been defined that the filesystem is
	152	* only local if it is all local, ie the MNT_LOCAL flag implies
	153	* that the entire namespace is local. If you think the MNT_LOCAL
	154	* flag implies that some of the files might be stored locally
	155	* then you will want to change the conditional.
	156	*/
c1b204a8 JSP	157	if (um->um_op == UNMNT_ABOVE) {
	158	if (((um->um_lowervp == NULLVP) \|\|
	159	(um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
	160	(um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
	161	mp->mnt_flag \|= MNT_LOCAL;
	162	}
3b293975	163
81be6ee0 JSP	164	/*
	165	* Copy in the upper layer's RDONLY flag. This is for the benefit
	166	* of lookup() which explicitly checks the flag, rather than asking
	167	* the filesystem for it's own opinion. This means, that an update
	168	* mount of the underlying filesystem to go from rdonly to rdwr
	169	* will leave the unioned view as read-only.
	170	*/
692a90df	171	mp->mnt_flag \|= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);
bc0d9070	172
a1fa407d JSP	173	mp->mnt_data = (qaddr_t) um;
	174	getnewfsid(mp, MOUNT_UNION);
	175
	176	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
	177	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
692a90df	178
c1b204a8	179	switch (um->um_op) {
692a90df	180	case UNMNT_ABOVE:
178b36c0	181	cp = "<above>:";
692a90df JSP	182	break;
692a90df JSP	183	case UNMNT_BELOW:
178b36c0	184	cp = "<below>:";
692a90df JSP	185	break;
692a90df JSP	186	case UNMNT_REPLACE:
c80f414e	187	cp = "";
692a90df JSP	188	break;
	189	}
	190	len = strlen(cp);
	191	bcopy(cp, mp->mnt_stat.f_mntfromname, len);
	192
	193	cp = mp->mnt_stat.f_mntfromname + len;
	194	len = MNAMELEN - len;
	195
	196	(void) copyinstr(args.target, cp, len - 1, &size);
	197	bzero(cp + size, len - size);
	198
a1fa407d	199	#ifdef UNION_DIAGNOSTIC
692a90df	200	printf("union_mount: from %s, on %s\n",
a1fa407d JSP	201	mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
	202	#endif
	203	return (0);
692a90df JSP	204
692a90df JSP	205	bad:
88edbcd4 JSP	206	if (um)
88edbcd4 JSP	207	free(um, M_UFSMNT);
692a90df JSP	208	if (cred)
	209	crfree(cred);
	210	if (upperrootvp)
	211	vrele(upperrootvp);
	212	if (lowerrootvp)
	213	vrele(lowerrootvp);
	214	return (error);
a1fa407d JSP	215	}
	216
	217	/*
	218	* VFS start. Nothing needed here - the start routine
	219	* on the underlying filesystem(s) will have been called
	220	* when that filesystem was mounted.
	221	*/
	222	int
	223	union_start(mp, flags, p)
	224	struct mount *mp;
	225	int flags;
	226	struct proc *p;
	227	{
	228
	229	return (0);
	230	}
	231
	232	/*
	233	* Free reference to union layer
	234	*/
	235	int
	236	union_unmount(mp, mntflags, p)
	237	struct mount *mp;
	238	int mntflags;
	239	struct proc *p;
	240	{
	241	struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
	242	struct vnode *um_rootvp;
	243	int error;
9192c54f	244	int freeing;
a1fa407d JSP	245	int flags = 0;
	246	extern int doforce;
	247
	248	#ifdef UNION_DIAGNOSTIC
	249	printf("union_unmount(mp = %x)\n", mp);
	250	#endif
	251
	252	if (mntflags & MNT_FORCE) {
	253	/* union can never be rootfs so don't check for it */
	254	if (!doforce)
	255	return (EINVAL);
	256	flags \|= FORCECLOSE;
	257	}
	258
	259	if (error = union_root(mp, &um_rootvp))
	260	return (error);
9192c54f JSP	261
	262	/*
	263	* Keep flushing vnodes from the mount list.
	264	* This is needed because of the un_pvp held
	265	* reference to the parent vnode.
	266	* If more vnodes have been freed on a given pass,
	267	* the try again. The loop will iterate at most
	268	* (d) times, where (d) is the maximum tree depth
	269	* in the filesystem.
	270	*/
	271	for (freeing = 0; vflush(mp, um_rootvp, flags) != 0;) {
	272	struct vnode *vp;
	273	int n;
	274
	275	/* count #vnodes held on mount list */
	276	for (n = 0, vp = mp->mnt_vnodelist.lh_first;
	277	vp != NULLVP;
	278	vp = vp->v_mntvnodes.le_next)
	279	n++;
	280
	281	/* if this is unchanged then stop */
	282	if (n == freeing)
	283	break;
	284
	285	/* otherwise try once more time */
	286	freeing = n;
	287	}
	288
	289	/* At this point the root vnode should have a single reference */
01dac67e JSP	290	if (um_rootvp->v_usecount > 1) {
01dac67e JSP	291	vput(um_rootvp);
a1fa407d	292	return (EBUSY);
01dac67e	293	}
a1fa407d JSP	294
a1fa407d JSP	295	#ifdef UNION_DIAGNOSTIC
9192c54f	296	vprint("union root", um_rootvp);
a1fa407d JSP	297	#endif
	298	/*
	299	* Discard references to upper and lower target vnodes.
	300	*/
692a90df JSP	301	if (um->um_lowervp)
692a90df JSP	302	vrele(um->um_lowervp);
a1fa407d JSP	303	vrele(um->um_uppervp);
	304	crfree(um->um_cred);
	305	/*
	306	* Release reference on underlying root vnode
	307	*/
01dac67e	308	vput(um_rootvp);
a1fa407d JSP	309	/*
	310	* And blow it away for future re-use
	311	*/
	312	vgone(um_rootvp);
	313	/*
	314	* Finally, throw away the union_mount structure
	315	*/
	316	free(mp->mnt_data, M_UFSMNT); /* XXX */
	317	mp->mnt_data = 0;
3b293975	318	return (0);
a1fa407d JSP	319	}
	320
	321	int
	322	union_root(mp, vpp)
	323	struct mount *mp;
	324	struct vnode **vpp;
	325	{
	326	struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
	327	int error;
c1b204a8	328	int loselock;
a1fa407d	329
a1fa407d JSP	330	/*
	331	* Return locked reference to root.
	332	*/
01dac67e	333	VREF(um->um_uppervp);
c1b204a8 JSP	334	if ((um->um_op == UNMNT_BELOW) &&
	335	VOP_ISLOCKED(um->um_uppervp)) {
	336	loselock = 1;
	337	} else {
	338	VOP_LOCK(um->um_uppervp);
	339	loselock = 0;
	340	}
692a90df JSP	341	if (um->um_lowervp)
692a90df JSP	342	VREF(um->um_lowervp);
79f80c71 JSP	343	error = union_allocvp(vpp, mp,
	344	(struct vnode *) 0,
	345	(struct vnode *) 0,
a1fa407d JSP	346	(struct componentname *) 0,
a1fa407d JSP	347	um->um_uppervp,
825ff80f JSP	348	um->um_lowervp,
825ff80f JSP	349	1);
01dac67e JSP	350
01dac67e JSP	351	if (error) {
c1b204a8 JSP	352	if (!loselock)
c1b204a8 JSP	353	VOP_UNLOCK(um->um_uppervp);
01dac67e	354	vrele(um->um_uppervp);
692a90df JSP	355	if (um->um_lowervp)
692a90df JSP	356	vrele(um->um_lowervp);
01dac67e	357	} else {
c1b204a8 JSP	358	if (loselock)
c1b204a8 JSP	359	VTOUNION(*vpp)->un_flags &= ~UN_ULOCK;
01dac67e	360	}
a1fa407d JSP	361
	362	return (error);
	363	}
	364
	365	int
	366	union_quotactl(mp, cmd, uid, arg, p)
	367	struct mount *mp;
	368	int cmd;
	369	uid_t uid;
	370	caddr_t arg;
	371	struct proc *p;
	372	{
	373
	374	return (EOPNOTSUPP);
	375	}
	376
	377	int
	378	union_statfs(mp, sbp, p)
	379	struct mount *mp;
	380	struct statfs *sbp;
	381	struct proc *p;
	382	{
	383	int error;
	384	struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
	385	struct statfs mstat;
	386	int lbsize;
	387
	388	#ifdef UNION_DIAGNOSTIC
	389	printf("union_statfs(mp = %x, lvp = %x, uvp = %x)\n", mp,
	390	um->um_lowervp,
	391	um->um_uppervp);
	392	#endif
	393
	394	bzero(&mstat, sizeof(mstat));
	395
692a90df JSP	396	if (um->um_lowervp) {
	397	error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p);
	398	if (error)
	399	return (error);
	400	}
a1fa407d JSP	401
	402	/* now copy across the "interesting" information and fake the rest */
	403	#if 0
	404	sbp->f_type = mstat.f_type;
	405	sbp->f_flags = mstat.f_flags;
	406	sbp->f_bsize = mstat.f_bsize;
	407	sbp->f_iosize = mstat.f_iosize;
	408	#endif
	409	lbsize = mstat.f_bsize;
	410	sbp->f_blocks = mstat.f_blocks;
	411	sbp->f_bfree = mstat.f_bfree;
	412	sbp->f_bavail = mstat.f_bavail;
	413	sbp->f_files = mstat.f_files;
	414	sbp->f_ffree = mstat.f_ffree;
	415
	416	error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p);
	417	if (error)
	418	return (error);
	419
84d17267	420	sbp->f_type = MOUNT_UNION;
a1fa407d JSP	421	sbp->f_flags = mstat.f_flags;
	422	sbp->f_bsize = mstat.f_bsize;
	423	sbp->f_iosize = mstat.f_iosize;
	424
	425	/*
	426	* if the lower and upper blocksizes differ, then frig the
	427	* block counts so that the sizes reported by df make some
	428	* kind of sense. none of this makes sense though.
	429	*/
	430
8583490d	431	if (mstat.f_bsize != lbsize)
a1fa407d	432	sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize;
8583490d JSP	433
	434	/*
	435	* The "total" fields count total resources in all layers,
	436	* the "free" fields count only those resources which are
	437	* free in the upper layer (since only the upper layer
	438	* is writeable).
	439	*/
a1fa407d	440	sbp->f_blocks += mstat.f_blocks;
8583490d JSP	441	sbp->f_bfree = mstat.f_bfree;
8583490d JSP	442	sbp->f_bavail = mstat.f_bavail;
a1fa407d	443	sbp->f_files += mstat.f_files;
8583490d	444	sbp->f_ffree = mstat.f_ffree;
a1fa407d JSP	445
	446	if (sbp != &mp->mnt_stat) {
	447	bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
	448	bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
	449	bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
	450	}
	451	return (0);
	452	}
	453
	454	int
	455	union_sync(mp, waitfor, cred, p)
	456	struct mount *mp;
	457	int waitfor;
	458	struct ucred *cred;
	459	struct proc *p;
	460	{
	461
	462	/*
	463	* XXX - Assumes no data cached at union layer.
	464	*/
	465	return (0);
	466	}
	467
	468	int
	469	union_vget(mp, ino, vpp)
	470	struct mount *mp;
	471	ino_t ino;
	472	struct vnode **vpp;
	473	{
	474
	475	return (EOPNOTSUPP);
	476	}
	477
	478	int
	479	union_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
	480	struct mount *mp;
	481	struct fid *fidp;
	482	struct mbuf *nam;
	483	struct vnode **vpp;
	484	int *exflagsp;
	485	struct ucred **credanonp;
	486	{
	487
	488	return (EOPNOTSUPP);
	489	}
	490
	491	int
	492	union_vptofh(vp, fhp)
	493	struct vnode *vp;
	494	struct fid *fhp;
	495	{
	496
	497	return (EOPNOTSUPP);
	498	}
	499
	500	int union_init __P((void));
	501
	502	struct vfsops union_vfsops = {
	503	union_mount,
	504	union_start,
	505	union_unmount,
	506	union_root,
	507	union_quotactl,
	508	union_statfs,
509	union_sync,
510	union_vget,
511	union_fhtovp,
512	union_vptofh,
513	union_init,
514	};