1 /* 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)dead_vnops.c 8.1 (Berkeley) 6/10/93 34 * $FreeBSD: src/sys/miscfs/deadfs/dead_vnops.c,v 1.26 1999/08/28 00:46:42 peter Exp $ 35 * $DragonFly: src/sys/vfs/deadfs/dead_vnops.c,v 1.10 2004/08/17 18:57:33 dillon Exp $ 36 */ 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/vnode.h> 43 #include <sys/buf.h> 44 #include <sys/poll.h> 45 46 static int chkvnlock (struct vnode *); 47 /* 48 * Prototypes for dead operations on vnodes. 49 */ 50 static int dead_badop (void); 51 static int dead_bmap (struct vop_bmap_args *); 52 static int dead_ioctl (struct vop_ioctl_args *); 53 static int dead_lock (struct vop_lock_args *); 54 static int dead_lookup (struct vop_lookup_args *); 55 static int dead_open (struct vop_open_args *); 56 static int dead_poll (struct vop_poll_args *); 57 static int dead_print (struct vop_print_args *); 58 static int dead_read (struct vop_read_args *); 59 static int dead_write (struct vop_write_args *); 60 61 struct vop_ops *dead_vnode_vops; 62 static struct vnodeopv_entry_desc dead_vnodeop_entries[] = { 63 { &vop_default_desc, vop_defaultop }, 64 { &vop_access_desc, vop_ebadf }, 65 { &vop_advlock_desc, vop_ebadf }, 66 { &vop_bmap_desc, (void *) dead_bmap }, 67 { &vop_create_desc, (void *) dead_badop }, 68 { &vop_getattr_desc, vop_ebadf }, 69 { &vop_inactive_desc, vop_null }, 70 { &vop_ioctl_desc, (void *) dead_ioctl }, 71 { &vop_link_desc, (void *) dead_badop }, 72 { &vop_lock_desc, (void *) dead_lock }, 73 { &vop_lookup_desc, (void *) dead_lookup }, 74 { &vop_mkdir_desc, (void *) dead_badop }, 75 { &vop_mknod_desc, (void *) dead_badop }, 76 { &vop_mmap_desc, (void *) dead_badop }, 77 { &vop_open_desc, (void *) dead_open }, 78 { &vop_pathconf_desc, vop_ebadf }, /* per pathconf(2) */ 79 { &vop_poll_desc, (void *) dead_poll }, 80 { &vop_print_desc, (void *) dead_print }, 81 { &vop_read_desc, (void *) dead_read }, 82 { &vop_readdir_desc, vop_ebadf }, 83 { &vop_readlink_desc, vop_ebadf }, 84 { &vop_reclaim_desc, vop_null }, 85 { &vop_remove_desc, (void *) dead_badop }, 86 { &vop_rename_desc, (void *) dead_badop }, 87 { &vop_rmdir_desc, (void *) dead_badop }, 88 { &vop_setattr_desc, vop_ebadf }, 89 { &vop_symlink_desc, (void *) dead_badop }, 90 { &vop_write_desc, (void *) dead_write }, 91 { NULL, NULL } 92 }; 93 static struct vnodeopv_desc dead_vnodeop_opv_desc = 94 { &dead_vnode_vops, dead_vnodeop_entries }; 95 96 VNODEOP_SET(dead_vnodeop_opv_desc); 97 98 /* 99 * Trivial lookup routine that always fails. 100 * 101 * dead_lookup(struct vnode *a_dvp, struct vnode **a_vpp, 102 * struct componentname *a_cnp) 103 */ 104 /* ARGSUSED */ 105 static int 106 dead_lookup(struct vop_lookup_args *ap) 107 { 108 *ap->a_vpp = NULL; 109 return (ENOTDIR); 110 } 111 112 /* 113 * Open always fails as if device did not exist. 114 * 115 * dead_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred, 116 * struct proc *a_p) 117 */ 118 /* ARGSUSED */ 119 static int 120 dead_open(struct vop_open_args *ap) 121 { 122 return (ENXIO); 123 } 124 125 /* 126 * Vnode op for read 127 * 128 * dead_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag, 129 * struct ucred *a_cred) 130 */ 131 /* ARGSUSED */ 132 static int 133 dead_read(struct vop_read_args *ap) 134 { 135 if (chkvnlock(ap->a_vp)) 136 panic("dead_read: lock"); 137 /* 138 * Return EOF for tty devices, EIO for others 139 */ 140 if ((ap->a_vp->v_flag & VISTTY) == 0) 141 return (EIO); 142 return (0); 143 } 144 145 /* 146 * Vnode op for write 147 * 148 * dead_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag, 149 * struct ucred *a_cred) 150 */ 151 /* ARGSUSED */ 152 static int 153 dead_write(struct vop_write_args *ap) 154 { 155 if (chkvnlock(ap->a_vp)) 156 panic("dead_write: lock"); 157 return (EIO); 158 } 159 160 /* 161 * Device ioctl operation. 162 * 163 * dead_ioctl(struct vnode *a_vp, int a_command, caddr_t a_data, int a_fflag, 164 * struct ucred *a_cred, struct proc *a_p) 165 */ 166 /* ARGSUSED */ 167 static int 168 dead_ioctl(struct vop_ioctl_args *ap) 169 { 170 if (!chkvnlock(ap->a_vp)) 171 return (ENOTTY); 172 return (vop_ioctl_ap(ap)); 173 } 174 175 /* 176 * Wait until the vnode has finished changing state. 177 * 178 * dead_lock(struct vnode *a_vp, lwkt_tokref_t a_vlock, int a_flags, 179 * struct proc *a_p) 180 */ 181 static int 182 dead_lock(struct vop_lock_args *ap) 183 { 184 struct vnode *vp = ap->a_vp; 185 186 /* 187 * Since we are not using the lock manager, we must clear 188 * the interlock here. 189 */ 190 if (ap->a_flags & LK_INTERLOCK) { 191 lwkt_reltoken(ap->a_vlock); 192 ap->a_flags &= ~LK_INTERLOCK; 193 } 194 if (!chkvnlock(vp)) 195 return (0); 196 return (vop_lock_ap(ap)); 197 } 198 199 /* 200 * Wait until the vnode has finished changing state. 201 * 202 * dead_bmap(struct vnode *a_vp, daddr_t a_bn, struct vnode **a_vpp, 203 * daddr_t *a_bnp, int *a_runp, int *a_runb) 204 */ 205 static int 206 dead_bmap(struct vop_bmap_args *ap) 207 { 208 if (!chkvnlock(ap->a_vp)) 209 return (EIO); 210 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp, ap->a_runb)); 211 } 212 213 /* 214 * Print out the contents of a dead vnode. 215 * 216 * dead_print(struct vnode *a_vp) 217 */ 218 /* ARGSUSED */ 219 static int 220 dead_print(struct vop_print_args *ap) 221 { 222 printf("tag VT_NON, dead vnode\n"); 223 return (0); 224 } 225 226 /* 227 * Empty vnode bad operation 228 */ 229 static int 230 dead_badop(void) 231 { 232 panic("dead_badop called"); 233 /* NOTREACHED */ 234 } 235 236 /* 237 * We have to wait during times when the vnode is 238 * in a state of change. 239 */ 240 int 241 chkvnlock(struct vnode *vp) 242 { 243 int locked = 0; 244 245 while (vp->v_flag & VXLOCK) { 246 vp->v_flag |= VXWANT; 247 (void) tsleep((caddr_t)vp, 0, "ckvnlk", 0); 248 locked = 1; 249 } 250 return (locked); 251 } 252 253 /* 254 * Trivial poll routine that always returns POLLHUP. 255 * This is necessary so that a process which is polling a file 256 * gets notified when that file is revoke()d. 257 */ 258 static int 259 dead_poll(struct vop_poll_args *ap) 260 { 261 return (POLLHUP); 262 } 263