union_vnops.c

来自「早期freebsd实现」· C语言 代码 · 共 1,496 行 · 第 1/3 页

bad:
	vrele(fdvp);
	vrele(fvp);
	vput(tdvp);
	if (tvp)
		vput(tvp);

	return (error);
}

int
union_mkdir(ap)
	struct vop_mkdir_args /* {
		struct vnode *a_dvp;
		struct vnode **a_vpp;
		struct componentname *a_cnp;
		struct vattr *a_vap;
	} */ *ap;
{
	struct union_node *un = VTOUNION(ap->a_dvp);
	struct vnode *dvp = un->un_uppervp;

	if (dvp) {
		int error;
		struct vnode *vp;

		FIXUP(un);
		VREF(dvp);
		un->un_flags |= UN_KLOCK;
		vput(ap->a_dvp);
		error = VOP_MKDIR(dvp, &vp, ap->a_cnp, ap->a_vap);
		if (error)
			return (error);

		error = union_allocvp(
				ap->a_vpp,
				ap->a_dvp->v_mount,
				ap->a_dvp,
				NULLVP,
				ap->a_cnp,
				vp,
				NULLVP);
		if (error)
			vput(vp);
		return (error);
	}

	vput(ap->a_dvp);
	return (EROFS);
}

int
union_rmdir(ap)
	struct vop_rmdir_args /* {
		struct vnode *a_dvp;
		struct vnode *a_vp;
		struct componentname *a_cnp;
	} */ *ap;
{
	int error;
	struct union_node *dun = VTOUNION(ap->a_dvp);
	struct union_node *un = VTOUNION(ap->a_vp);

	if (dun->un_uppervp && un->un_uppervp) {
		struct vnode *dvp = dun->un_uppervp;
		struct vnode *vp = un->un_uppervp;

		FIXUP(dun);
		VREF(dvp);
		dun->un_flags |= UN_KLOCK;
		vput(ap->a_dvp);
		FIXUP(un);
		VREF(vp);
		un->un_flags |= UN_KLOCK;
		vput(ap->a_vp);

		error = VOP_RMDIR(dvp, vp, ap->a_cnp);
		if (!error)
			union_removed_upper(un);

		/*
		 * XXX: should create a whiteout here
		 */
	} else {
		/*
		 * XXX: should create a whiteout here
		 */
		vput(ap->a_dvp);
		vput(ap->a_vp);
		error = EROFS;
	}

	return (error);
}

int
union_symlink(ap)
	struct vop_symlink_args /* {
		struct vnode *a_dvp;
		struct vnode **a_vpp;
		struct componentname *a_cnp;
		struct vattr *a_vap;
		char *a_target;
	} */ *ap;
{
	struct union_node *un = VTOUNION(ap->a_dvp);
	struct vnode *dvp = un->un_uppervp;

	if (dvp) {
		int error;
		struct vnode *vp;
		struct mount *mp = ap->a_dvp->v_mount;

		FIXUP(un);
		VREF(dvp);
		un->un_flags |= UN_KLOCK;
		vput(ap->a_dvp);
		error = VOP_SYMLINK(dvp, &vp, ap->a_cnp,
					ap->a_vap, ap->a_target);
		*ap->a_vpp = NULLVP;
		return (error);
	}

	vput(ap->a_dvp);
	return (EROFS);
}

/*
 * union_readdir works in concert with getdirentries and
 * readdir(3) to provide a list of entries in the unioned
 * directories.  getdirentries is responsible for walking
 * down the union stack.  readdir(3) is responsible for
 * eliminating duplicate names from the returned data stream.
 */
int
union_readdir(ap)
	struct vop_readdir_args /* {
		struct vnodeop_desc *a_desc;
		struct vnode *a_vp;
		struct uio *a_uio;
		struct ucred *a_cred;
	} */ *ap;
{
	int error = 0;
	struct union_node *un = VTOUNION(ap->a_vp);

	if (un->un_uppervp) {
		FIXUP(un);
		error = VOP_READDIR(un->un_uppervp, ap->a_uio, ap->a_cred);
	}

	return (error);
}

int
union_readlink(ap)
	struct vop_readlink_args /* {
		struct vnode *a_vp;
		struct uio *a_uio;
		struct ucred *a_cred;
	} */ *ap;
{
	int error;
	struct vnode *vp = OTHERVP(ap->a_vp);
	int dolock = (vp == LOWERVP(ap->a_vp));

	if (dolock)
		VOP_LOCK(vp);
	else
		FIXUP(VTOUNION(ap->a_vp));
	error = VOP_READLINK(vp, ap->a_uio, ap->a_cred);
	if (dolock)
		VOP_UNLOCK(vp);

	return (error);
}

int
union_abortop(ap)
	struct vop_abortop_args /* {
		struct vnode *a_dvp;
		struct componentname *a_cnp;
	} */ *ap;
{
	int error;
	struct vnode *vp = OTHERVP(ap->a_dvp);
	struct union_node *un = VTOUNION(ap->a_dvp);
	int islocked = un->un_flags & UN_LOCKED;
	int dolock = (vp == LOWERVP(ap->a_dvp));

	if (islocked) {
		if (dolock)
			VOP_LOCK(vp);
		else
			FIXUP(VTOUNION(ap->a_dvp));
	}
	error = VOP_ABORTOP(vp, ap->a_cnp);
	if (islocked && dolock)
		VOP_UNLOCK(vp);

	return (error);
}

int
union_inactive(ap)
	struct vop_inactive_args /* {
		struct vnode *a_vp;
	} */ *ap;
{

	/*
	 * Do nothing (and _don't_ bypass).
	 * Wait to vrele lowervp until reclaim,
	 * so that until then our union_node is in the
	 * cache and reusable.
	 *
	 * NEEDSWORK: Someday, consider inactive'ing
	 * the lowervp and then trying to reactivate it
	 * with capabilities (v_id)
	 * like they do in the name lookup cache code.
	 * That's too much work for now.
	 */

#ifdef UNION_DIAGNOSTIC
	struct union_node *un = VTOUNION(ap->a_vp);

	if (un->un_flags & UN_LOCKED)
		panic("union: inactivating locked node");
#endif

	return (0);
}

int
union_reclaim(ap)
	struct vop_reclaim_args /* {
		struct vnode *a_vp;
	} */ *ap;
{

	union_freevp(ap->a_vp);

	return (0);
}

int
union_lock(ap)
	struct vop_lock_args *ap;
{
	struct vnode *vp = ap->a_vp;
	struct union_node *un;

start:
	while (vp->v_flag & VXLOCK) {
		vp->v_flag |= VXWANT;
		sleep((caddr_t)vp, PINOD);
	}

	un = VTOUNION(vp);

	if (un->un_uppervp) {
		if ((un->un_flags & UN_ULOCK) == 0) {
			un->un_flags |= UN_ULOCK;
			VOP_LOCK(un->un_uppervp);
		}
#ifdef DIAGNOSTIC
		if (un->un_flags & UN_KLOCK)
			panic("union: dangling upper lock");
#endif
	}

	if (un->un_flags & UN_LOCKED) {
#ifdef DIAGNOSTIC
		if (curproc && un->un_pid == curproc->p_pid &&
			    un->un_pid > -1 && curproc->p_pid > -1)
			panic("union: locking against myself");
#endif
		un->un_flags |= UN_WANT;
		sleep((caddr_t) &un->un_flags, PINOD);
		goto start;
	}

#ifdef DIAGNOSTIC
	if (curproc)
		un->un_pid = curproc->p_pid;
	else
		un->un_pid = -1;
#endif

	un->un_flags |= UN_LOCKED;
	return (0);
}

int
union_unlock(ap)
	struct vop_lock_args *ap;
{
	struct union_node *un = VTOUNION(ap->a_vp);

#ifdef DIAGNOSTIC
	if ((un->un_flags & UN_LOCKED) == 0)
		panic("union: unlock unlocked node");
	if (curproc && un->un_pid != curproc->p_pid &&
			curproc->p_pid > -1 && un->un_pid > -1)
		panic("union: unlocking other process's union node");
#endif

	un->un_flags &= ~UN_LOCKED;

	if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK)
		VOP_UNLOCK(un->un_uppervp);

	un->un_flags &= ~(UN_ULOCK|UN_KLOCK);

	if (un->un_flags & UN_WANT) {
		un->un_flags &= ~UN_WANT;
		wakeup((caddr_t) &un->un_flags);
	}

#ifdef DIAGNOSTIC
	un->un_pid = 0;
#endif

	return (0);
}

int
union_bmap(ap)
	struct vop_bmap_args /* {
		struct vnode *a_vp;
		daddr_t  a_bn;
		struct vnode **a_vpp;
		daddr_t *a_bnp;
		int *a_runp;
	} */ *ap;
{
	int error;
	struct vnode *vp = OTHERVP(ap->a_vp);
	int dolock = (vp == LOWERVP(ap->a_vp));

	if (dolock)
		VOP_LOCK(vp);
	else
		FIXUP(VTOUNION(ap->a_vp));
	error = VOP_BMAP(vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp);
	if (dolock)
		VOP_UNLOCK(vp);

	return (error);
}

int
union_print(ap)
	struct vop_print_args /* {
		struct vnode *a_vp;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;

	printf("\ttag VT_UNION, vp=%x, uppervp=%x, lowervp=%x\n",
			vp, UPPERVP(vp), LOWERVP(vp));
	return (0);
}

int
union_islocked(ap)
	struct vop_islocked_args /* {
		struct vnode *a_vp;
	} */ *ap;
{

	return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0);
}

int
union_pathconf(ap)
	struct vop_pathconf_args /* {
		struct vnode *a_vp;
		int a_name;
		int *a_retval;
	} */ *ap;
{
	int error;
	struct vnode *vp = OTHERVP(ap->a_vp);
	int dolock = (vp == LOWERVP(ap->a_vp));

	if (dolock)
		VOP_LOCK(vp);
	else
		FIXUP(VTOUNION(ap->a_vp));
	error = VOP_PATHCONF(vp, ap->a_name, ap->a_retval);
	if (dolock)
		VOP_UNLOCK(vp);

	return (error);
}

int
union_advlock(ap)
	struct vop_advlock_args /* {
		struct vnode *a_vp;
		caddr_t  a_id;
		int  a_op;
		struct flock *a_fl;
		int  a_flags;
	} */ *ap;
{

	return (VOP_ADVLOCK(OTHERVP(ap->a_vp), ap->a_id, ap->a_op,
				ap->a_fl, ap->a_flags));
}


/*
 * XXX - vop_strategy must be hand coded because it has no
 * vnode in its arguments.
 * This goes away with a merged VM/buffer cache.
 */
int
union_strategy(ap)
	struct vop_strategy_args /* {
		struct buf *a_bp;
	} */ *ap;
{
	struct buf *bp = ap->a_bp;
	int error;
	struct vnode *savedvp;

	savedvp = bp->b_vp;
	bp->b_vp = OTHERVP(bp->b_vp);

#ifdef DIAGNOSTIC
	if (bp->b_vp == NULLVP)
		panic("union_strategy: nil vp");
	if (((bp->b_flags & B_READ) == 0) &&
	    (bp->b_vp == LOWERVP(savedvp)))
		panic("union_strategy: writing to lowervp");
#endif

	error = VOP_STRATEGY(bp);
	bp->b_vp = savedvp;

	return (error);
}

/*
 * Global vfs data structures
 */
int (**union_vnodeop_p)();
struct vnodeopv_entry_desc union_vnodeop_entries[] = {
	{ &vop_default_desc, vn_default_error },
	{ &vop_lookup_desc, union_lookup },		/* lookup */
	{ &vop_create_desc, union_create },		/* create */
	{ &vop_mknod_desc, union_mknod },		/* mknod */
	{ &vop_open_desc, union_open },			/* open */
	{ &vop_close_desc, union_close },		/* close */
	{ &vop_access_desc, union_access },		/* access */
	{ &vop_getattr_desc, union_getattr },		/* getattr */
	{ &vop_setattr_desc, union_setattr },		/* setattr */
	{ &vop_read_desc, union_read },			/* read */
	{ &vop_write_desc, union_write },		/* write */
	{ &vop_ioctl_desc, union_ioctl },		/* ioctl */
	{ &vop_select_desc, union_select },		/* select */
	{ &vop_mmap_desc, union_mmap },			/* mmap */
	{ &vop_fsync_desc, union_fsync },		/* fsync */
	{ &vop_seek_desc, union_seek },			/* seek */
	{ &vop_remove_desc, union_remove },		/* remove */
	{ &vop_link_desc, union_link },			/* link */
	{ &vop_rename_desc, union_rename },		/* rename */
	{ &vop_mkdir_desc, union_mkdir },		/* mkdir */
	{ &vop_rmdir_desc, union_rmdir },		/* rmdir */
	{ &vop_symlink_desc, union_symlink },		/* symlink */
	{ &vop_readdir_desc, union_readdir },		/* readdir */
	{ &vop_readlink_desc, union_readlink },		/* readlink */
	{ &vop_abortop_desc, union_abortop },		/* abortop */
	{ &vop_inactive_desc, union_inactive },		/* inactive */
	{ &vop_reclaim_desc, union_reclaim },		/* reclaim */
	{ &vop_lock_desc, union_lock },			/* lock */
	{ &vop_unlock_desc, union_unlock },		/* unlock */
	{ &vop_bmap_desc, union_bmap },			/* bmap */
	{ &vop_strategy_desc, union_strategy },		/* strategy */
	{ &vop_print_desc, union_print },		/* print */
	{ &vop_islocked_desc, union_islocked },		/* islocked */
	{ &vop_pathconf_desc, union_pathconf },		/* pathconf */
	{ &vop_advlock_desc, union_advlock },		/* advlock */
#ifdef notdef
	{ &vop_blkatoff_desc, union_blkatoff },		/* blkatoff */
	{ &vop_valloc_desc, union_valloc },		/* valloc */
	{ &vop_vfree_desc, union_vfree },		/* vfree */
	{ &vop_truncate_desc, union_truncate },		/* truncate */
	{ &vop_update_desc, union_update },		/* update */
	{ &vop_bwrite_desc, union_bwrite },		/* bwrite */
#endif
	{ (struct vnodeop_desc*)NULL, (int(*)())NULL }
};
struct vnodeopv_desc union_vnodeop_opv_desc =
	{ &union_vnodeop_p, union_vnodeop_entries };