1 /* $OpenBSD: vfs_default.c,v 1.50 2021/10/15 06:30:06 semarie Exp $ */ 2 3 /* 4 * Portions of this code are: 5 * 6 * Copyright (c) 1989, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/mount.h> 42 #include <sys/vnode.h> 43 #include <sys/namei.h> 44 #include <sys/pool.h> 45 #include <sys/event.h> 46 #include <sys/specdev.h> 47 48 int filt_generic_readwrite(struct knote *, long); 49 void filt_generic_detach(struct knote *); 50 51 /* 52 * Eliminate all activity associated with the requested vnode 53 * and with all vnodes aliased to the requested vnode. 54 */ 55 int 56 vop_generic_revoke(void *v) 57 { 58 struct vop_revoke_args *ap = v; 59 struct vnode *vp, *vq; 60 struct proc *p = curproc; 61 62 #ifdef DIAGNOSTIC 63 if ((ap->a_flags & REVOKEALL) == 0) 64 panic("vop_generic_revoke"); 65 #endif 66 67 vp = ap->a_vp; 68 69 while (vp->v_type == VBLK && vp->v_specinfo != NULL && 70 vp->v_specmountpoint != NULL) { 71 struct mount *mp = vp->v_specmountpoint; 72 73 /* 74 * If we have a mount point associated with the vnode, we must 75 * flush it out now, as to not leave a dangling zombie mount 76 * point laying around in VFS. 77 */ 78 if (!vfs_busy(mp, VB_WRITE|VB_WAIT)) { 79 dounmount(mp, MNT_FORCE | MNT_DOOMED, p); 80 break; 81 } 82 } 83 84 if (vp->v_flag & VALIASED) { 85 /* 86 * If a vgone (or vclean) is already in progress, 87 * wait until it is done and return. 88 */ 89 mtx_enter(&vnode_mtx); 90 if (vp->v_lflag & VXLOCK) { 91 vp->v_lflag |= VXWANT; 92 msleep_nsec(vp, &vnode_mtx, PINOD, 93 "vop_generic_revokeall", INFSLP); 94 mtx_leave(&vnode_mtx); 95 return(0); 96 } 97 98 /* 99 * Ensure that vp will not be vgone'd while we 100 * are eliminating its aliases. 101 */ 102 vp->v_lflag |= VXLOCK; 103 mtx_leave(&vnode_mtx); 104 105 while (vp->v_flag & VALIASED) { 106 SLIST_FOREACH(vq, vp->v_hashchain, v_specnext) { 107 if (vq->v_rdev != vp->v_rdev || 108 vq->v_type != vp->v_type || vp == vq) 109 continue; 110 vgone(vq); 111 break; 112 } 113 } 114 115 /* 116 * Remove the lock so that vgone below will 117 * really eliminate the vnode after which time 118 * vgone will awaken any sleepers. 119 */ 120 mtx_enter(&vnode_mtx); 121 vp->v_lflag &= ~VXLOCK; 122 mtx_leave(&vnode_mtx); 123 } 124 125 vgonel(vp, p); 126 127 return (0); 128 } 129 130 int 131 vop_generic_badop(void *v) 132 { 133 panic("%s", __func__); 134 } 135 136 int 137 vop_generic_bmap(void *v) 138 { 139 struct vop_bmap_args *ap = v; 140 141 if (ap->a_vpp) 142 *ap->a_vpp = ap->a_vp; 143 if (ap->a_bnp) 144 *ap->a_bnp = ap->a_bn; 145 if (ap->a_runp) 146 *ap->a_runp = 0; 147 148 return (0); 149 } 150 151 int 152 vop_generic_bwrite(void *v) 153 { 154 struct vop_bwrite_args *ap = v; 155 156 return (bwrite(ap->a_bp)); 157 } 158 159 int 160 vop_generic_abortop(void *v) 161 { 162 struct vop_abortop_args *ap = v; 163 164 if ((ap->a_cnp->cn_flags & (HASBUF | SAVESTART)) == HASBUF) 165 pool_put(&namei_pool, ap->a_cnp->cn_pnbuf); 166 167 return (0); 168 } 169 170 const struct filterops generic_filtops = { 171 .f_flags = FILTEROP_ISFD, 172 .f_attach = NULL, 173 .f_detach = filt_generic_detach, 174 .f_event = filt_generic_readwrite, 175 }; 176 177 int 178 vop_generic_kqfilter(void *v) 179 { 180 struct vop_kqfilter_args *ap = v; 181 struct knote *kn = ap->a_kn; 182 183 switch (kn->kn_filter) { 184 case EVFILT_READ: 185 case EVFILT_WRITE: 186 kn->kn_fop = &generic_filtops; 187 break; 188 default: 189 return (EINVAL); 190 } 191 192 return (0); 193 } 194 195 /* Trivial lookup routine that always fails. */ 196 int 197 vop_generic_lookup(void *v) 198 { 199 struct vop_lookup_args *ap = v; 200 201 *ap->a_vpp = NULL; 202 return (ENOTDIR); 203 } 204 205 void 206 filt_generic_detach(struct knote *kn) 207 { 208 } 209 210 int 211 filt_generic_readwrite(struct knote *kn, long hint) 212 { 213 /* 214 * filesystem is gone, so set the EOF flag and schedule 215 * the knote for deletion. 216 */ 217 if (hint == NOTE_REVOKE) { 218 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 219 return (1); 220 } 221 222 kn->kn_data = 0; 223 224 return (1); 225 } 226