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dead_vnops.c revision 1.44.6.3 
      1 /*	dead_vnops.c,v 1.44.6.2 2008/01/09 01:57:00 matt 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, "dead_vnops.c,v 1.44.6.2 2008/01/09 01:57:00 matt 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_fcntl	genfs_nullop
     56 int	dead_ioctl(void *);
     57 int	dead_poll(void *);
     58 #define dead_fsync	genfs_nullop
     59 #define dead_seek	genfs_nullop
     60 #define dead_inactive	genfs_nullop
     61 #define dead_reclaim	genfs_nullop
     62 int	dead_lock(void *);
     63 #define dead_unlock	genfs_nullop
     64 int	dead_bmap(void *);
     65 int	dead_strategy(void *);
     66 int	dead_print(void *);
     67 #define dead_islocked	genfs_nullop
     68 #define dead_bwrite	genfs_nullop
     69 #define dead_revoke	genfs_nullop
     70 int	dead_getpages(void *);
     71 #define dead_putpages	genfs_null_putpages
     72 
     73 int	chkvnlock(struct vnode *, bool);
     74 int	dead_default_error(void *);
     75 
     76 int (**dead_vnodeop_p)(void *);
     77 
     78 const struct vnodeopv_entry_desc dead_vnodeop_entries[] = {
     79 	{ &vop_default_desc, dead_default_error },
     80 	{ &vop_open_desc, dead_open },			/* open */
     81 	{ &vop_close_desc, dead_close },		/* close */
     82 	{ &vop_read_desc, dead_read },			/* read */
     83 	{ &vop_write_desc, dead_write },		/* write */
     84 	{ &vop_fcntl_desc, dead_fcntl },		/* fcntl */
     85 	{ &vop_ioctl_desc, dead_ioctl },		/* ioctl */
     86 	{ &vop_poll_desc, dead_poll },			/* poll */
     87 	{ &vop_revoke_desc, dead_revoke },		/* revoke */
     88 	{ &vop_fsync_desc, dead_fsync },		/* fsync */
     89 	{ &vop_seek_desc, dead_seek },			/* seek */
     90 	{ &vop_inactive_desc, dead_inactive },		/* inactive */
     91 	{ &vop_reclaim_desc, dead_reclaim },		/* reclaim */
     92 	{ &vop_lock_desc, dead_lock },			/* lock */
     93 	{ &vop_unlock_desc, dead_unlock },		/* unlock */
     94 	{ &vop_bmap_desc, dead_bmap },			/* bmap */
     95 	{ &vop_strategy_desc, dead_strategy },		/* strategy */
     96 	{ &vop_print_desc, dead_print },		/* print */
     97 	{ &vop_islocked_desc, dead_islocked },		/* islocked */
     98 	{ &vop_bwrite_desc, dead_bwrite },		/* bwrite */
     99 	{ &vop_getpages_desc, dead_getpages },		/* getpages */
    100 	{ &vop_putpages_desc, dead_putpages },		/* putpages */
    101 	{ NULL, NULL }
    102 };
    103 const struct vnodeopv_desc dead_vnodeop_opv_desc =
    104 	{ &dead_vnodeop_p, dead_vnodeop_entries };
    105 
    106 int
    107 dead_default_error(void *v)
    108 {
    109 
    110 	return EBADF;
    111 }
    112 
    113 /*
    114  * Open always fails as if device did not exist.
    115  */
    116 /* ARGSUSED */
    117 int
    118 dead_open(void *v)
    119 {
    120 
    121 	return (ENXIO);
    122 }
    123 
    124 /*
    125  * Vnode op for read
    126  */
    127 /* ARGSUSED */
    128 int
    129 dead_read(v)
    130 	void *v;
    131 {
    132 	struct vop_read_args /* {
    133 		struct vnode *a_vp;
    134 		struct uio *a_uio;
    135 		int  a_ioflag;
    136 		kauth_cred_t a_cred;
    137 	} */ *ap = v;
    138 
    139 	if (chkvnlock(ap->a_vp, false))
    140 		panic("dead_read: lock");
    141 	/*
    142 	 * Return EOF for tty devices, EIO for others
    143 	 */
    144 	if ((ap->a_vp->v_vflag & VV_ISTTY) == 0)
    145 		return (EIO);
    146 	return (0);
    147 }
    148 
    149 /*
    150  * Vnode op for write
    151  */
    152 /* ARGSUSED */
    153 int
    154 dead_write(v)
    155 	void *v;
    156 {
    157 	struct vop_write_args /* {
    158 		struct vnode *a_vp;
    159 		struct uio *a_uio;
    160 		int  a_ioflag;
    161 		kauth_cred_t a_cred;
    162 	} */ *ap = v;
    163 
    164 	if (chkvnlock(ap->a_vp, false))
    165 		panic("dead_write: lock");
    166 	return (EIO);
    167 }
    168 
    169 /*
    170  * Device ioctl operation.
    171  */
    172 /* ARGSUSED */
    173 int
    174 dead_ioctl(v)
    175 	void *v;
    176 {
    177 	struct vop_ioctl_args /* {
    178 		struct vnode *a_vp;
    179 		u_long a_command;
    180 		void *a_data;
    181 		int  a_fflag;
    182 		kauth_cred_t a_cred;
    183 		struct lwp *a_l;
    184 	} */ *ap = v;
    185 
    186 	if (!chkvnlock(ap->a_vp, false))
    187 		return (EBADF);
    188 	return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap));
    189 }
    190 
    191 /* ARGSUSED */
    192 int
    193 dead_poll(v)
    194 	void *v;
    195 {
    196 	struct vop_poll_args /* {
    197 		struct vnode *a_vp;
    198 		int a_events;
    199 		struct lwp *a_l;
    200 	} */ *ap = v;
    201 
    202 	/*
    203 	 * Let the user find out that the descriptor is gone.
    204 	 */
    205 	return (ap->a_events);
    206 }
    207 
    208 /*
    209  * Just call the device strategy routine
    210  */
    211 int
    212 dead_strategy(v)
    213 	void *v;
    214 {
    215 
    216 	struct vop_strategy_args /* {
    217 		struct vnode *a_vp;
    218 		struct buf *a_bp;
    219 	} */ *ap = v;
    220 	struct buf *bp;
    221 	if (ap->a_vp == NULL || !chkvnlock(ap->a_vp, false)) {
    222 		bp = ap->a_bp;
    223 		bp->b_error = EIO;
    224 		bp->b_resid = bp->b_bcount;
    225 		biodone(ap->a_bp);
    226 		return (EIO);
    227 	}
    228 	return (VOP_STRATEGY(ap->a_vp, ap->a_bp));
    229 }
    230 
    231 /*
    232  * Wait until the vnode has finished changing state.
    233  */
    234 int
    235 dead_lock(v)
    236 	void *v;
    237 {
    238 	struct vop_lock_args /* {
    239 		struct vnode *a_vp;
    240 		int a_flags;
    241 		struct proc *a_p;
    242 	} */ *ap = v;
    243 	bool interlock;
    244 
    245 	if (ap->a_flags & LK_INTERLOCK) {
    246 		interlock = true;
    247 		ap->a_flags &= ~LK_INTERLOCK;
    248 	} else
    249 		interlock = false;
    250 	if (!chkvnlock(ap->a_vp, interlock))
    251 		return (0);
    252 	return (VCALL(ap->a_vp, VOFFSET(vop_lock), ap));
    253 }
    254 
    255 /*
    256  * Wait until the vnode has finished changing state.
    257  */
    258 int
    259 dead_bmap(v)
    260 	void *v;
    261 {
    262 	struct vop_bmap_args /* {
    263 		struct vnode *a_vp;
    264 		daddr_t  a_bn;
    265 		struct vnode **a_vpp;
    266 		daddr_t *a_bnp;
    267 		int *a_runp;
    268 	} */ *ap = v;
    269 
    270 	if (!chkvnlock(ap->a_vp, false))
    271 		return (EIO);
    272 	return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp));
    273 }
    274 
    275 /*
    276  * Print out the contents of a dead vnode.
    277  */
    278 /* ARGSUSED */
    279 int
    280 dead_print(void *v)
    281 {
    282 	printf("tag VT_NON, dead vnode\n");
    283 	return 0;
    284 }
    285 
    286 int
    287 dead_getpages(void *v)
    288 {
    289 	struct vop_getpages_args /* {
    290 		struct vnode *a_vp;
    291 		voff_t a_offset;
    292 		struct vm_page **a_m;
    293 		int *a_count;
    294 		int a_centeridx;
    295 		vm_prot_t a_access_type;
    296 		int a_advice;
    297 		int a_flags;
    298 	} */ *ap = v;
    299 
    300 	if ((ap->a_flags & PGO_LOCKED) == 0)
    301 		mutex_exit(&ap->a_vp->v_interlock);
    302 
    303 	return (EFAULT);
    304 }
    305 
    306 /*
    307  * We have to wait during times when the vnode is
    308  * in a state of change.
    309  */
    310 int
    311 chkvnlock(vp, interlock)
    312 	struct vnode *vp;
    313 	bool interlock;
    314 {
    315 	int locked = 0;
    316 
    317 	if (!interlock)
    318 		mutex_enter(&vp->v_interlock);
    319 	while (vp->v_iflag & VI_XLOCK) {
    320 		vwait(vp, VI_XLOCK);
    321 		locked = 1;
    322 	}
    323 	mutex_exit(&vp->v_interlock);
    324 
    325 	return (locked);
    326 }
    327