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dead_vnops.c revision 1.35.12.2 
      1 /*	$NetBSD: dead_vnops.c,v 1.35.12.2 2006/12/30 20:50:17 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  *	@(#)dead_vnops.c	8.2 (Berkeley) 11/21/94
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 __KERNEL_RCSID(0, "$NetBSD: dead_vnops.c,v 1.35.12.2 2006/12/30 20:50:17 yamt Exp $");
     36 
     37 #include <sys/param.h>
     38 #include <sys/systm.h>
     39 #include <sys/time.h>
     40 #include <sys/vnode.h>
     41 #include <sys/errno.h>
     42 #include <sys/namei.h>
     43 #include <sys/buf.h>
     44 #include <sys/proc.h>
     45 
     46 #include <miscfs/genfs/genfs.h>
     47 
     48 /*
     49  * Prototypes for dead operations on vnodes.
     50  */
     51 int	dead_open(void *);
     52 #define dead_close	genfs_nullop
     53 int	dead_read(void *);
     54 int	dead_write(void *);
     55 #define dead_lease_check genfs_nullop
     56 #define dead_fcntl	genfs_nullop
     57 int	dead_ioctl(void *);
     58 int	dead_poll(void *);
     59 #define dead_fsync	genfs_nullop
     60 #define dead_seek	genfs_nullop
     61 #define dead_inactive	genfs_nullop
     62 #define dead_reclaim	genfs_nullop
     63 int	dead_lock(void *);
     64 #define dead_unlock	genfs_nullop
     65 int	dead_bmap(void *);
     66 int	dead_strategy(void *);
     67 int	dead_print(void *);
     68 #define dead_islocked	genfs_nullop
     69 #define dead_bwrite	genfs_nullop
     70 #define dead_revoke	genfs_nullop
     71 int	dead_getpages(void *);
     72 #define dead_putpages	genfs_null_putpages
     73 
     74 int	chkvnlock(struct vnode *);
     75 int	dead_default_error(void *);
     76 
     77 int (**dead_vnodeop_p)(void *);
     78 
     79 const struct vnodeopv_entry_desc dead_vnodeop_entries[] = {
     80 	{ &vop_default_desc, dead_default_error },
     81 	{ &vop_open_desc, dead_open },			/* open */
     82 	{ &vop_close_desc, dead_close },		/* close */
     83 	{ &vop_read_desc, dead_read },			/* read */
     84 	{ &vop_write_desc, dead_write },		/* write */
     85 	{ &vop_lease_desc, dead_lease_check },		/* lease */
     86 	{ &vop_fcntl_desc, dead_fcntl },		/* fcntl */
     87 	{ &vop_ioctl_desc, dead_ioctl },		/* ioctl */
     88 	{ &vop_poll_desc, dead_poll },			/* poll */
     89 	{ &vop_revoke_desc, dead_revoke },		/* revoke */
     90 	{ &vop_fsync_desc, dead_fsync },		/* fsync */
     91 	{ &vop_seek_desc, dead_seek },			/* seek */
     92 	{ &vop_inactive_desc, dead_inactive },		/* inactive */
     93 	{ &vop_reclaim_desc, dead_reclaim },		/* reclaim */
     94 	{ &vop_lock_desc, dead_lock },			/* lock */
     95 	{ &vop_unlock_desc, dead_unlock },		/* unlock */
     96 	{ &vop_bmap_desc, dead_bmap },			/* bmap */
     97 	{ &vop_strategy_desc, dead_strategy },		/* strategy */
     98 	{ &vop_print_desc, dead_print },		/* print */
     99 	{ &vop_islocked_desc, dead_islocked },		/* islocked */
    100 	{ &vop_bwrite_desc, dead_bwrite },		/* bwrite */
    101 	{ &vop_getpages_desc, dead_getpages },		/* getpages */
    102 	{ &vop_putpages_desc, dead_putpages },		/* putpages */
    103 	{ NULL, NULL }
    104 };
    105 const struct vnodeopv_desc dead_vnodeop_opv_desc =
    106 	{ &dead_vnodeop_p, dead_vnodeop_entries };
    107 
    108 int
    109 dead_default_error(void *v)
    110 {
    111 
    112 	return EBADF;
    113 }
    114 
    115 /*
    116  * Open always fails as if device did not exist.
    117  */
    118 /* ARGSUSED */
    119 int
    120 dead_open(void *v)
    121 {
    122 
    123 	return (ENXIO);
    124 }
    125 
    126 /*
    127  * Vnode op for read
    128  */
    129 /* ARGSUSED */
    130 int
    131 dead_read(v)
    132 	void *v;
    133 {
    134 	struct vop_read_args /* {
    135 		struct vnode *a_vp;
    136 		struct uio *a_uio;
    137 		int  a_ioflag;
    138 		kauth_cred_t a_cred;
    139 	} */ *ap = v;
    140 
    141 	if (chkvnlock(ap->a_vp))
    142 		panic("dead_read: lock");
    143 	/*
    144 	 * Return EOF for tty devices, EIO for others
    145 	 */
    146 	if ((ap->a_vp->v_flag & VISTTY) == 0)
    147 		return (EIO);
    148 	return (0);
    149 }
    150 
    151 /*
    152  * Vnode op for write
    153  */
    154 /* ARGSUSED */
    155 int
    156 dead_write(v)
    157 	void *v;
    158 {
    159 	struct vop_write_args /* {
    160 		struct vnode *a_vp;
    161 		struct uio *a_uio;
    162 		int  a_ioflag;
    163 		kauth_cred_t a_cred;
    164 	} */ *ap = v;
    165 
    166 	if (chkvnlock(ap->a_vp))
    167 		panic("dead_write: lock");
    168 	return (EIO);
    169 }
    170 
    171 /*
    172  * Device ioctl operation.
    173  */
    174 /* ARGSUSED */
    175 int
    176 dead_ioctl(v)
    177 	void *v;
    178 {
    179 	struct vop_ioctl_args /* {
    180 		struct vnode *a_vp;
    181 		u_long a_command;
    182 		void *a_data;
    183 		int  a_fflag;
    184 		kauth_cred_t a_cred;
    185 		struct lwp *a_l;
    186 	} */ *ap = v;
    187 
    188 	if (!chkvnlock(ap->a_vp))
    189 		return (EBADF);
    190 	return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap));
    191 }
    192 
    193 /* ARGSUSED */
    194 int
    195 dead_poll(v)
    196 	void *v;
    197 {
    198 	struct vop_poll_args /* {
    199 		struct vnode *a_vp;
    200 		int a_events;
    201 		struct lwp *a_l;
    202 	} */ *ap = v;
    203 
    204 	/*
    205 	 * Let the user find out that the descriptor is gone.
    206 	 */
    207 	return (ap->a_events);
    208 }
    209 
    210 /*
    211  * Just call the device strategy routine
    212  */
    213 int
    214 dead_strategy(v)
    215 	void *v;
    216 {
    217 
    218 	struct vop_strategy_args /* {
    219 		struct vnode *a_vp;
    220 		struct buf *a_bp;
    221 	} */ *ap = v;
    222 	if (ap->a_vp == NULL || !chkvnlock(ap->a_vp)) {
    223 		ap->a_bp->b_flags |= B_ERROR;
    224 		biodone(ap->a_bp);
    225 		return (EIO);
    226 	}
    227 	return (VOP_STRATEGY(ap->a_vp, ap->a_bp));
    228 }
    229 
    230 /*
    231  * Wait until the vnode has finished changing state.
    232  */
    233 int
    234 dead_lock(v)
    235 	void *v;
    236 {
    237 	struct vop_lock_args /* {
    238 		struct vnode *a_vp;
    239 		int a_flags;
    240 		struct proc *a_p;
    241 	} */ *ap = v;
    242 
    243 	if (ap->a_flags & LK_INTERLOCK) {
    244 		simple_unlock(&ap->a_vp->v_interlock);
    245 		ap->a_flags &= ~LK_INTERLOCK;
    246 	}
    247 	if (!chkvnlock(ap->a_vp))
    248 		return (0);
    249 	return (VCALL(ap->a_vp, VOFFSET(vop_lock), ap));
    250 }
    251 
    252 /*
    253  * Wait until the vnode has finished changing state.
    254  */
    255 int
    256 dead_bmap(v)
    257 	void *v;
    258 {
    259 	struct vop_bmap_args /* {
    260 		struct vnode *a_vp;
    261 		daddr_t  a_bn;
    262 		struct vnode **a_vpp;
    263 		daddr_t *a_bnp;
    264 		int *a_runp;
    265 	} */ *ap = v;
    266 
    267 	if (!chkvnlock(ap->a_vp))
    268 		return (EIO);
    269 	return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp));
    270 }
    271 
    272 /*
    273  * Print out the contents of a dead vnode.
    274  */
    275 /* ARGSUSED */
    276 int
    277 dead_print(void *v)
    278 {
    279 	printf("tag VT_NON, dead vnode\n");
    280 	return 0;
    281 }
    282 
    283 int
    284 dead_getpages(void *v)
    285 {
    286 	struct vop_getpages_args /* {
    287 		struct vnode *a_vp;
    288 		voff_t a_offset;
    289 		struct vm_page **a_m;
    290 		int *a_count;
    291 		int a_centeridx;
    292 		vm_prot_t a_access_type;
    293 		int a_advice;
    294 		int a_flags;
    295 	} */ *ap = v;
    296 
    297 	if ((ap->a_flags & PGO_LOCKED) == 0)
    298 		simple_unlock(&ap->a_vp->v_interlock);
    299 
    300 	return (EFAULT);
    301 }
    302 
    303 /*
    304  * We have to wait during times when the vnode is
    305  * in a state of change.
    306  */
    307 int
    308 chkvnlock(vp)
    309 	struct vnode *vp;
    310 {
    311 	int locked = 0;
    312 
    313 	while (vp->v_flag & VXLOCK) {
    314 		vp->v_flag |= VXWANT;
    315 		(void) tsleep(vp, PINOD, "deadchk", 0);
    316 		locked = 1;
    317 	}
    318 	return (locked);
    319 }
    320