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dead_vnops.c revision 1.21 
      1 /*	$NetBSD: dead_vnops.c,v 1.21 1996/10/13 02:21:25 christos 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  *
     35  *	@(#)dead_vnops.c	8.2 (Berkeley) 11/21/94
     36  */
     37 
     38 #include <sys/param.h>
     39 #include <sys/systm.h>
     40 #include <sys/time.h>
     41 #include <sys/vnode.h>
     42 #include <sys/errno.h>
     43 #include <sys/namei.h>
     44 #include <sys/buf.h>
     45 #include <sys/proc.h>
     46 
     47 #include <miscfs/genfs/genfs.h>
     48 
     49 /*
     50  * Prototypes for dead operations on vnodes.
     51  */
     52 int	dead_lookup	__P((void *));
     53 #define dead_create	genfs_badop
     54 #define dead_mknod	genfs_badop
     55 int	dead_open	__P((void *));
     56 #define dead_close	genfs_nullop
     57 #define dead_access	genfs_ebadf
     58 #define dead_getattr	genfs_ebadf
     59 #define dead_setattr	genfs_ebadf
     60 int	dead_read	__P((void *));
     61 int	dead_write	__P((void *));
     62 int	dead_ioctl	__P((void *));
     63 int	dead_poll	__P((void *));
     64 #define dead_mmap	genfs_badop
     65 #define dead_fsync	genfs_nullop
     66 #define dead_seek	genfs_nullop
     67 #define dead_remove	genfs_badop
     68 #define dead_link	genfs_badop
     69 #define dead_rename	genfs_badop
     70 #define dead_mkdir	genfs_badop
     71 #define dead_rmdir	genfs_badop
     72 #define dead_symlink	genfs_badop
     73 #define dead_readdir	genfs_ebadf
     74 #define dead_readlink	genfs_ebadf
     75 #define dead_abortop	genfs_badop
     76 #define dead_inactive	genfs_nullop
     77 #define dead_reclaim	genfs_nullop
     78 int	dead_lock	__P((void *));
     79 #define dead_unlock	genfs_nullop
     80 int	dead_bmap	__P((void *));
     81 int	dead_strategy	__P((void *));
     82 int	dead_print	__P((void *));
     83 #define dead_islocked	genfs_nullop
     84 #define dead_pathconf	genfs_ebadf
     85 #define dead_advlock	genfs_ebadf
     86 #define dead_blkatoff	genfs_badop
     87 #define dead_valloc	genfs_badop
     88 #define dead_vfree	genfs_badop
     89 #define dead_truncate	genfs_nullop
     90 #define dead_update	genfs_nullop
     91 #define dead_bwrite	genfs_nullop
     92 
     93 int	chkvnlock __P((struct vnode *));
     94 
     95 int (**dead_vnodeop_p) __P((void *));
     96 
     97 struct vnodeopv_entry_desc dead_vnodeop_entries[] = {
     98 	{ &vop_default_desc, vn_default_error },
     99 	{ &vop_lookup_desc, dead_lookup },		/* lookup */
    100 	{ &vop_create_desc, dead_create },		/* create */
    101 	{ &vop_mknod_desc, dead_mknod },		/* mknod */
    102 	{ &vop_open_desc, dead_open },			/* open */
    103 	{ &vop_close_desc, dead_close },		/* close */
    104 	{ &vop_access_desc, dead_access },		/* access */
    105 	{ &vop_getattr_desc, dead_getattr },		/* getattr */
    106 	{ &vop_setattr_desc, dead_setattr },		/* setattr */
    107 	{ &vop_read_desc, dead_read },			/* read */
    108 	{ &vop_write_desc, dead_write },		/* write */
    109 	{ &vop_ioctl_desc, dead_ioctl },		/* ioctl */
    110 	{ &vop_poll_desc, dead_poll },			/* poll */
    111 	{ &vop_mmap_desc, dead_mmap },			/* mmap */
    112 	{ &vop_fsync_desc, dead_fsync },		/* fsync */
    113 	{ &vop_seek_desc, dead_seek },			/* seek */
    114 	{ &vop_remove_desc, dead_remove },		/* remove */
    115 	{ &vop_link_desc, dead_link },			/* link */
    116 	{ &vop_rename_desc, dead_rename },		/* rename */
    117 	{ &vop_mkdir_desc, dead_mkdir },		/* mkdir */
    118 	{ &vop_rmdir_desc, dead_rmdir },		/* rmdir */
    119 	{ &vop_symlink_desc, dead_symlink },		/* symlink */
    120 	{ &vop_readdir_desc, dead_readdir },		/* readdir */
    121 	{ &vop_readlink_desc, dead_readlink },		/* readlink */
    122 	{ &vop_abortop_desc, dead_abortop },		/* abortop */
    123 	{ &vop_inactive_desc, dead_inactive },		/* inactive */
    124 	{ &vop_reclaim_desc, dead_reclaim },		/* reclaim */
    125 	{ &vop_lock_desc, dead_lock },			/* lock */
    126 	{ &vop_unlock_desc, dead_unlock },		/* unlock */
    127 	{ &vop_bmap_desc, dead_bmap },			/* bmap */
    128 	{ &vop_strategy_desc, dead_strategy },		/* strategy */
    129 	{ &vop_print_desc, dead_print },		/* print */
    130 	{ &vop_islocked_desc, dead_islocked },		/* islocked */
    131 	{ &vop_pathconf_desc, dead_pathconf },		/* pathconf */
    132 	{ &vop_advlock_desc, dead_advlock },		/* advlock */
    133 	{ &vop_blkatoff_desc, dead_blkatoff },		/* blkatoff */
    134 	{ &vop_valloc_desc, dead_valloc },		/* valloc */
    135 	{ &vop_vfree_desc, dead_vfree },		/* vfree */
    136 	{ &vop_truncate_desc, dead_truncate },		/* truncate */
    137 	{ &vop_update_desc, dead_update },		/* update */
    138 	{ &vop_bwrite_desc, dead_bwrite },		/* bwrite */
    139 	{ (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL }
    140 };
    141 struct vnodeopv_desc dead_vnodeop_opv_desc =
    142 	{ &dead_vnodeop_p, dead_vnodeop_entries };
    143 
    144 /*
    145  * Trivial lookup routine that always fails.
    146  */
    147 /* ARGSUSED */
    148 int
    149 dead_lookup(v)
    150 	void *v;
    151 {
    152 	struct vop_lookup_args /* {
    153 		struct vnode * a_dvp;
    154 		struct vnode ** a_vpp;
    155 		struct componentname * a_cnp;
    156 	} */ *ap = v;
    157 
    158 	*ap->a_vpp = NULL;
    159 	return (ENOTDIR);
    160 }
    161 
    162 /*
    163  * Open always fails as if device did not exist.
    164  */
    165 /* ARGSUSED */
    166 int
    167 dead_open(v)
    168 	void *v;
    169 {
    170 
    171 	return (ENXIO);
    172 }
    173 
    174 /*
    175  * Vnode op for read
    176  */
    177 /* ARGSUSED */
    178 int
    179 dead_read(v)
    180 	void *v;
    181 {
    182 	struct vop_read_args /* {
    183 		struct vnode *a_vp;
    184 		struct uio *a_uio;
    185 		int  a_ioflag;
    186 		struct ucred *a_cred;
    187 	} */ *ap = v;
    188 
    189 	if (chkvnlock(ap->a_vp))
    190 		panic("dead_read: lock");
    191 	/*
    192 	 * Return EOF for tty devices, EIO for others
    193 	 */
    194 	if ((ap->a_vp->v_flag & VISTTY) == 0)
    195 		return (EIO);
    196 	return (0);
    197 }
    198 
    199 /*
    200  * Vnode op for write
    201  */
    202 /* ARGSUSED */
    203 int
    204 dead_write(v)
    205 	void *v;
    206 {
    207 	struct vop_write_args /* {
    208 		struct vnode *a_vp;
    209 		struct uio *a_uio;
    210 		int  a_ioflag;
    211 		struct ucred *a_cred;
    212 	} */ *ap = v;
    213 
    214 	if (chkvnlock(ap->a_vp))
    215 		panic("dead_write: lock");
    216 	return (EIO);
    217 }
    218 
    219 /*
    220  * Device ioctl operation.
    221  */
    222 /* ARGSUSED */
    223 int
    224 dead_ioctl(v)
    225 	void *v;
    226 {
    227 	struct vop_ioctl_args /* {
    228 		struct vnode *a_vp;
    229 		u_long a_command;
    230 		caddr_t  a_data;
    231 		int  a_fflag;
    232 		struct ucred *a_cred;
    233 		struct proc *a_p;
    234 	} */ *ap = v;
    235 
    236 	if (!chkvnlock(ap->a_vp))
    237 		return (EBADF);
    238 	return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap));
    239 }
    240 
    241 /* ARGSUSED */
    242 int
    243 dead_poll(v)
    244 	void *v;
    245 {
    246 	struct vop_poll_args /* {
    247 		struct vnode *a_vp;
    248 		int a_events;
    249 		struct proc *a_p;
    250 	} */ *ap = v;
    251 
    252 	/*
    253 	 * Let the user find out that the descriptor is gone.
    254 	 */
    255 	return (ap->a_events);
    256 }
    257 
    258 /*
    259  * Just call the device strategy routine
    260  */
    261 int
    262 dead_strategy(v)
    263 	void *v;
    264 {
    265 
    266 	struct vop_strategy_args /* {
    267 		struct buf *a_bp;
    268 	} */ *ap = v;
    269 	if (ap->a_bp->b_vp == NULL || !chkvnlock(ap->a_bp->b_vp)) {
    270 		ap->a_bp->b_flags |= B_ERROR;
    271 		biodone(ap->a_bp);
    272 		return (EIO);
    273 	}
    274 	return (VOP_STRATEGY(ap->a_bp));
    275 }
    276 
    277 /*
    278  * Wait until the vnode has finished changing state.
    279  */
    280 int
    281 dead_lock(v)
    282 	void *v;
    283 {
    284 	struct vop_lock_args /* {
    285 		struct vnode *a_vp;
    286 	} */ *ap = v;
    287 
    288 	if (!chkvnlock(ap->a_vp))
    289 		return (0);
    290 	return (VCALL(ap->a_vp, VOFFSET(vop_lock), ap));
    291 }
    292 
    293 /*
    294  * Wait until the vnode has finished changing state.
    295  */
    296 int
    297 dead_bmap(v)
    298 	void *v;
    299 {
    300 	struct vop_bmap_args /* {
    301 		struct vnode *a_vp;
    302 		daddr_t  a_bn;
    303 		struct vnode **a_vpp;
    304 		daddr_t *a_bnp;
    305 		int *a_runp;
    306 	} */ *ap = v;
    307 
    308 	if (!chkvnlock(ap->a_vp))
    309 		return (EIO);
    310 	return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp));
    311 }
    312 
    313 /*
    314  * Print out the contents of a dead vnode.
    315  */
    316 /* ARGSUSED */
    317 int
    318 dead_print(v)
    319 	void *v;
    320 {
    321 	printf("tag VT_NON, dead vnode\n");
    322 	return 0;
    323 }
    324 
    325 /*
    326  * We have to wait during times when the vnode is
    327  * in a state of change.
    328  */
    329 int
    330 chkvnlock(vp)
    331 	register struct vnode *vp;
    332 {
    333 	int locked = 0;
    334 
    335 	while (vp->v_flag & VXLOCK) {
    336 		vp->v_flag |= VXWANT;
    337 		sleep((caddr_t)vp, PINOD);
    338 		locked = 1;
    339 	}
    340 	return (locked);
    341 }
    342