NetBSD-5.0.2/sys/miscfs/deadfs/dead_vnops.c
/* $NetBSD: dead_vnops.c,v 1.47 2008/01/25 14:32:15 ad Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* 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. 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.
*
* @(#)dead_vnops.c 8.2 (Berkeley) 11/21/94
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: dead_vnops.c,v 1.47 2008/01/25 14:32:15 ad Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/vnode.h>
#include <sys/errno.h>
#include <sys/namei.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <miscfs/genfs/genfs.h>
/*
* Prototypes for dead operations on vnodes.
*/
int dead_open(void *);
#define dead_close genfs_nullop
int dead_read(void *);
int dead_write(void *);
#define dead_fcntl genfs_nullop
int dead_ioctl(void *);
int dead_poll(void *);
#define dead_fsync genfs_nullop
#define dead_seek genfs_nullop
#define dead_inactive genfs_nullop
#define dead_reclaim genfs_nullop
int dead_lock(void *);
#define dead_unlock genfs_nullop
int dead_bmap(void *);
int dead_strategy(void *);
int dead_print(void *);
#define dead_islocked genfs_nullop
#define dead_bwrite genfs_nullop
#define dead_revoke genfs_nullop
int dead_getpages(void *);
#define dead_putpages genfs_null_putpages
int chkvnlock(struct vnode *, bool);
int dead_default_error(void *);
int (**dead_vnodeop_p)(void *);
const struct vnodeopv_entry_desc dead_vnodeop_entries[] = {
{ &vop_default_desc, dead_default_error },
{ &vop_open_desc, dead_open }, /* open */
{ &vop_close_desc, dead_close }, /* close */
{ &vop_read_desc, dead_read }, /* read */
{ &vop_write_desc, dead_write }, /* write */
{ &vop_fcntl_desc, dead_fcntl }, /* fcntl */
{ &vop_ioctl_desc, dead_ioctl }, /* ioctl */
{ &vop_poll_desc, dead_poll }, /* poll */
{ &vop_revoke_desc, dead_revoke }, /* revoke */
{ &vop_fsync_desc, dead_fsync }, /* fsync */
{ &vop_seek_desc, dead_seek }, /* seek */
{ &vop_inactive_desc, dead_inactive }, /* inactive */
{ &vop_reclaim_desc, dead_reclaim }, /* reclaim */
{ &vop_lock_desc, dead_lock }, /* lock */
{ &vop_unlock_desc, dead_unlock }, /* unlock */
{ &vop_bmap_desc, dead_bmap }, /* bmap */
{ &vop_strategy_desc, dead_strategy }, /* strategy */
{ &vop_print_desc, dead_print }, /* print */
{ &vop_islocked_desc, dead_islocked }, /* islocked */
{ &vop_bwrite_desc, dead_bwrite }, /* bwrite */
{ &vop_getpages_desc, dead_getpages }, /* getpages */
{ &vop_putpages_desc, dead_putpages }, /* putpages */
{ NULL, NULL }
};
const struct vnodeopv_desc dead_vnodeop_opv_desc =
{ &dead_vnodeop_p, dead_vnodeop_entries };
int
dead_default_error(void *v)
{
return EBADF;
}
/*
* Open always fails as if device did not exist.
*/
/* ARGSUSED */
int
dead_open(void *v)
{
return (ENXIO);
}
/*
* Vnode op for read
*/
/* ARGSUSED */
int
dead_read(v)
void *v;
{
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
kauth_cred_t a_cred;
} */ *ap = v;
if (chkvnlock(ap->a_vp, false))
panic("dead_read: lock");
/*
* Return EOF for tty devices, EIO for others
*/
if ((ap->a_vp->v_vflag & VV_ISTTY) == 0)
return (EIO);
return (0);
}
/*
* Vnode op for write
*/
/* ARGSUSED */
int
dead_write(v)
void *v;
{
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
kauth_cred_t a_cred;
} */ *ap = v;
if (chkvnlock(ap->a_vp, false))
panic("dead_write: lock");
return (EIO);
}
/*
* Device ioctl operation.
*/
/* ARGSUSED */
int
dead_ioctl(v)
void *v;
{
struct vop_ioctl_args /* {
struct vnode *a_vp;
u_long a_command;
void *a_data;
int a_fflag;
kauth_cred_t a_cred;
struct lwp *a_l;
} */ *ap = v;
if (!chkvnlock(ap->a_vp, false))
return (EBADF);
return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap));
}
/* ARGSUSED */
int
dead_poll(v)
void *v;
{
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct lwp *a_l;
} */ *ap = v;
/*
* Let the user find out that the descriptor is gone.
*/
return (ap->a_events);
}
/*
* Just call the device strategy routine
*/
int
dead_strategy(v)
void *v;
{
struct vop_strategy_args /* {
struct vnode *a_vp;
struct buf *a_bp;
} */ *ap = v;
struct buf *bp;
if (ap->a_vp == NULL || !chkvnlock(ap->a_vp, false)) {
bp = ap->a_bp;
bp->b_error = EIO;
bp->b_resid = bp->b_bcount;
biodone(ap->a_bp);
return (EIO);
}
return (VOP_STRATEGY(ap->a_vp, ap->a_bp));
}
/*
* Wait until the vnode has finished changing state.
*/
int
dead_lock(v)
void *v;
{
struct vop_lock_args /* {
struct vnode *a_vp;
int a_flags;
struct proc *a_p;
} */ *ap = v;
bool interlock;
if (ap->a_flags & LK_INTERLOCK) {
interlock = true;
ap->a_flags &= ~LK_INTERLOCK;
} else
interlock = false;
if (!chkvnlock(ap->a_vp, interlock))
return (0);
return (VCALL(ap->a_vp, VOFFSET(vop_lock), ap));
}
/*
* Wait until the vnode has finished changing state.
*/
int
dead_bmap(v)
void *v;
{
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
} */ *ap = v;
if (!chkvnlock(ap->a_vp, false))
return (EIO);
return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp));
}
/*
* Print out the contents of a dead vnode.
*/
/* ARGSUSED */
int
dead_print(void *v)
{
printf("tag VT_NON, dead vnode\n");
return 0;
}
int
dead_getpages(void *v)
{
struct vop_getpages_args /* {
struct vnode *a_vp;
voff_t a_offset;
struct vm_page **a_m;
int *a_count;
int a_centeridx;
vm_prot_t a_access_type;
int a_advice;
int a_flags;
} */ *ap = v;
if ((ap->a_flags & PGO_LOCKED) == 0)
mutex_exit(&ap->a_vp->v_interlock);
return (EFAULT);
}
/*
* We have to wait during times when the vnode is
* in a state of change.
*/
int
chkvnlock(vp, interlock)
struct vnode *vp;
bool interlock;
{
int locked = 0;
if (!interlock)
mutex_enter(&vp->v_interlock);
while (vp->v_iflag & VI_XLOCK) {
vwait(vp, VI_XLOCK);
locked = 1;
}
mutex_exit(&vp->v_interlock);
return (locked);
}