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dead_vnops.c revision 1.14 
      1 /*	$NetBSD: dead_vnops.c,v 1.14 1996/02/09 22:39:56 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 /*
     48  * Prototypes for dead operations on vnodes.
     49  */
     50 int	dead_badop	__P((void *));
     51 int	dead_ebadf	__P((void *));
     52 int	dead_nullop	__P((void *));
     53 int	dead_lookup	__P((void *));
     54 #define dead_create	dead_badop
     55 #define dead_mknod	dead_badop
     56 int	dead_open	__P((void *));
     57 #define dead_close	nullop
     58 #define dead_access	dead_ebadf
     59 #define dead_getattr	dead_ebadf
     60 #define dead_setattr	dead_ebadf
     61 int	dead_read	__P((void *));
     62 int	dead_write	__P((void *));
     63 int	dead_ioctl	__P((void *));
     64 int	dead_select	__P((void *));
     65 #define dead_mmap	dead_badop
     66 #define dead_fsync	nullop
     67 #define dead_seek	nullop
     68 #define dead_remove	dead_badop
     69 #define dead_link	dead_badop
     70 #define dead_rename	dead_badop
     71 #define dead_mkdir	dead_badop
     72 #define dead_rmdir	dead_badop
     73 #define dead_symlink	dead_badop
     74 #define dead_readdir	dead_ebadf
     75 #define dead_readlink	dead_ebadf
     76 #define dead_abortop	dead_badop
     77 #define dead_inactive	nullop
     78 #define dead_reclaim	nullop
     79 int	dead_lock	__P((void *));
     80 #define dead_unlock	nullop
     81 int	dead_bmap	__P((void *));
     82 int	dead_strategy	__P((void *));
     83 int	dead_print	__P((void *));
     84 #define dead_islocked	nullop
     85 #define dead_pathconf	dead_ebadf
     86 #define dead_advlock	dead_ebadf
     87 #define dead_blkatoff	dead_badop
     88 #define dead_valloc	dead_badop
     89 #define dead_vfree	dead_badop
     90 #define dead_truncate	nullop
     91 #define dead_update	nullop
     92 #define dead_bwrite	nullop
     93 
     94 int	chkvnlock __P((struct vnode *));
     95 
     96 int (**dead_vnodeop_p) __P((void *));
     97 
     98 struct vnodeopv_entry_desc dead_vnodeop_entries[] = {
     99 	{ &vop_default_desc, vn_default_error },
    100 	{ &vop_lookup_desc, dead_lookup },	/* lookup */
    101 	{ &vop_create_desc, dead_create },	/* create */
    102 	{ &vop_mknod_desc, dead_mknod },	/* mknod */
    103 	{ &vop_open_desc, dead_open },		/* open */
    104 	{ &vop_close_desc, dead_close },	/* close */
    105 	{ &vop_access_desc, dead_access },	/* access */
    106 	{ &vop_getattr_desc, dead_getattr },	/* getattr */
    107 	{ &vop_setattr_desc, dead_setattr },	/* setattr */
    108 	{ &vop_read_desc, dead_read },		/* read */
    109 	{ &vop_write_desc, dead_write },	/* write */
    110 	{ &vop_ioctl_desc, dead_ioctl },	/* ioctl */
    111 	{ &vop_select_desc, dead_select },	/* select */
    112 	{ &vop_mmap_desc, dead_mmap },		/* mmap */
    113 	{ &vop_fsync_desc, dead_fsync },	/* fsync */
    114 	{ &vop_seek_desc, dead_seek },		/* seek */
    115 	{ &vop_remove_desc, dead_remove },	/* remove */
    116 	{ &vop_link_desc, dead_link },		/* link */
    117 	{ &vop_rename_desc, dead_rename },	/* rename */
    118 	{ &vop_mkdir_desc, dead_mkdir },	/* mkdir */
    119 	{ &vop_rmdir_desc, dead_rmdir },	/* rmdir */
    120 	{ &vop_symlink_desc, dead_symlink },	/* symlink */
    121 	{ &vop_readdir_desc, dead_readdir },	/* readdir */
    122 	{ &vop_readlink_desc, dead_readlink },	/* readlink */
    123 	{ &vop_abortop_desc, dead_abortop },	/* abortop */
    124 	{ &vop_inactive_desc, dead_inactive },	/* inactive */
    125 	{ &vop_reclaim_desc, dead_reclaim },	/* reclaim */
    126 	{ &vop_lock_desc, dead_lock },		/* lock */
    127 	{ &vop_unlock_desc, dead_unlock },	/* unlock */
    128 	{ &vop_bmap_desc, dead_bmap },		/* bmap */
    129 	{ &vop_strategy_desc, dead_strategy },	/* strategy */
    130 	{ &vop_print_desc, dead_print },	/* print */
    131 	{ &vop_islocked_desc, dead_islocked },	/* islocked */
    132 	{ &vop_pathconf_desc, dead_pathconf },	/* pathconf */
    133 	{ &vop_advlock_desc, dead_advlock },	/* advlock */
    134 	{ &vop_blkatoff_desc, dead_blkatoff },	/* blkatoff */
    135 	{ &vop_valloc_desc, dead_valloc },	/* valloc */
    136 	{ &vop_vfree_desc, dead_vfree },	/* vfree */
    137 	{ &vop_truncate_desc, dead_truncate },	/* truncate */
    138 	{ &vop_update_desc, dead_update },	/* update */
    139 	{ &vop_bwrite_desc, dead_bwrite },	/* bwrite */
    140 	{ (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL }
    141 };
    142 struct vnodeopv_desc dead_vnodeop_opv_desc =
    143 	{ &dead_vnodeop_p, dead_vnodeop_entries };
    144 
    145 /*
    146  * Trivial lookup routine that always fails.
    147  */
    148 /* ARGSUSED */
    149 int
    150 dead_lookup(v)
    151 	void *v;
    152 {
    153 	struct vop_lookup_args /* {
    154 		struct vnode * a_dvp;
    155 		struct vnode ** a_vpp;
    156 		struct componentname * a_cnp;
    157 	} */ *ap = v;
    158 
    159 	*ap->a_vpp = NULL;
    160 	return (ENOTDIR);
    161 }
    162 
    163 /*
    164  * Open always fails as if device did not exist.
    165  */
    166 /* ARGSUSED */
    167 int
    168 dead_open(v)
    169 	void *v;
    170 {
    171 
    172 	return (ENXIO);
    173 }
    174 
    175 /*
    176  * Vnode op for read
    177  */
    178 /* ARGSUSED */
    179 int
    180 dead_read(v)
    181 	void *v;
    182 {
    183 	struct vop_read_args /* {
    184 		struct vnode *a_vp;
    185 		struct uio *a_uio;
    186 		int  a_ioflag;
    187 		struct ucred *a_cred;
    188 	} */ *ap = v;
    189 
    190 	if (chkvnlock(ap->a_vp))
    191 		panic("dead_read: lock");
    192 	/*
    193 	 * Return EOF for tty devices, EIO for others
    194 	 */
    195 	if ((ap->a_vp->v_flag & VISTTY) == 0)
    196 		return (EIO);
    197 	return (0);
    198 }
    199 
    200 /*
    201  * Vnode op for write
    202  */
    203 /* ARGSUSED */
    204 int
    205 dead_write(v)
    206 	void *v;
    207 {
    208 	struct vop_write_args /* {
    209 		struct vnode *a_vp;
    210 		struct uio *a_uio;
    211 		int  a_ioflag;
    212 		struct ucred *a_cred;
    213 	} */ *ap = v;
    214 
    215 	if (chkvnlock(ap->a_vp))
    216 		panic("dead_write: lock");
    217 	return (EIO);
    218 }
    219 
    220 /*
    221  * Device ioctl operation.
    222  */
    223 /* ARGSUSED */
    224 int
    225 dead_ioctl(v)
    226 	void *v;
    227 {
    228 	struct vop_ioctl_args /* {
    229 		struct vnode *a_vp;
    230 		u_long a_command;
    231 		caddr_t  a_data;
    232 		int  a_fflag;
    233 		struct ucred *a_cred;
    234 		struct proc *a_p;
    235 	} */ *ap = v;
    236 
    237 	if (!chkvnlock(ap->a_vp))
    238 		return (EBADF);
    239 	return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap));
    240 }
    241 
    242 /* ARGSUSED */
    243 int
    244 dead_select(v)
    245 	void *v;
    246 {
    247 	/*
    248 	 * Let the user find out that the descriptor is gone.
    249 	 */
    250 	return (1);
    251 }
    252 
    253 /*
    254  * Just call the device strategy routine
    255  */
    256 int
    257 dead_strategy(v)
    258 	void *v;
    259 {
    260 
    261 	struct vop_strategy_args /* {
    262 		struct buf *a_bp;
    263 	} */ *ap = v;
    264 	if (ap->a_bp->b_vp == NULL || !chkvnlock(ap->a_bp->b_vp)) {
    265 		ap->a_bp->b_flags |= B_ERROR;
    266 		biodone(ap->a_bp);
    267 		return (EIO);
    268 	}
    269 	return (VOP_STRATEGY(ap->a_bp));
    270 }
    271 
    272 /*
    273  * Wait until the vnode has finished changing state.
    274  */
    275 int
    276 dead_lock(v)
    277 	void *v;
    278 {
    279 	struct vop_lock_args /* {
    280 		struct vnode *a_vp;
    281 	} */ *ap = v;
    282 
    283 	if (!chkvnlock(ap->a_vp))
    284 		return (0);
    285 	return (VCALL(ap->a_vp, VOFFSET(vop_lock), ap));
    286 }
    287 
    288 /*
    289  * Wait until the vnode has finished changing state.
    290  */
    291 int
    292 dead_bmap(v)
    293 	void *v;
    294 {
    295 	struct vop_bmap_args /* {
    296 		struct vnode *a_vp;
    297 		daddr_t  a_bn;
    298 		struct vnode **a_vpp;
    299 		daddr_t *a_bnp;
    300 		int *a_runp;
    301 	} */ *ap = v;
    302 
    303 	if (!chkvnlock(ap->a_vp))
    304 		return (EIO);
    305 	return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp));
    306 }
    307 
    308 /*
    309  * Print out the contents of a dead vnode.
    310  */
    311 /* ARGSUSED */
    312 int
    313 dead_print(v)
    314 	void *v;
    315 {
    316 	printf("tag VT_NON, dead vnode\n");
    317 	return 0;
    318 }
    319 
    320 /*
    321  * Empty vnode failed operation
    322  */
    323 /*ARGSUSED*/
    324 int
    325 dead_ebadf(v)
    326 	void *v;
    327 {
    328 
    329 	return (EBADF);
    330 }
    331 
    332 /*
    333  * Empty vnode bad operation
    334  */
    335 /*ARGSUSED*/
    336 int
    337 dead_badop(v)
    338 	void *v;
    339 {
    340 
    341 	panic("dead_badop called");
    342 	/* NOTREACHED */
    343 }
    344 
    345 /*
    346  * Empty vnode null operation
    347  */
    348 /*ARGSUSED*/
    349 int
    350 dead_nullop(v)
    351 	void *v;
    352 {
    353 
    354 	return (0);
    355 }
    356 
    357 /*
    358  * We have to wait during times when the vnode is
    359  * in a state of change.
    360  */
    361 int
    362 chkvnlock(vp)
    363 	register struct vnode *vp;
    364 {
    365 	int locked = 0;
    366 
    367 	while (vp->v_flag & VXLOCK) {
    368 		vp->v_flag |= VXWANT;
    369 		sleep((caddr_t)vp, PINOD);
    370 		locked = 1;
    371 	}
    372 	return (locked);
    373 }
    374