1 /* $NetBSD: null_vfsops.c,v 1.36 2001/11/10 13:33:42 lukem Exp $ */ 2 3 /* 4 * Copyright (c) 1999 National Aeronautics & Space Administration 5 * All rights reserved. 6 * 7 * This software was written by William Studenmund of the 8 * Numerical Aerospace Simulation Facility, NASA Ames Research Center. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the National Aeronautics & Space Administration 19 * nor the names of its contributors may be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB- 27 * UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 28 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 /* 36 * Copyright (c) 1992, 1993, 1995 37 * The Regents of the University of California. All rights reserved. 38 * 39 * This code is derived from software donated to Berkeley by 40 * Jan-Simon Pendry. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. All advertising materials mentioning features or use of this software 51 * must display the following acknowledgement: 52 * This product includes software developed by the University of 53 * California, Berkeley and its contributors. 54 * 4. Neither the name of the University nor the names of its contributors 55 * may be used to endorse or promote products derived from this software 56 * without specific prior written permission. 57 * 58 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 59 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 60 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 61 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 62 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 63 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 64 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 65 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 66 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 67 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 68 * SUCH DAMAGE. 69 * 70 * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp 71 * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 72 * @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95 73 */ 74 75 /* 76 * Null Layer 77 * (See null_vnops.c for a description of what this does.) 78 */ 79 80 #include <sys/cdefs.h> 81 __KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.36 2001/11/10 13:33:42 lukem Exp $"); 82 83 #include <sys/param.h> 84 #include <sys/systm.h> 85 #include <sys/time.h> 86 #include <sys/proc.h> 87 #include <sys/vnode.h> 88 #include <sys/mount.h> 89 #include <sys/namei.h> 90 #include <sys/malloc.h> 91 92 #include <miscfs/nullfs/null.h> 93 #include <miscfs/genfs/layer_extern.h> 94 95 int nullfs_mount __P((struct mount *, const char *, void *, 96 struct nameidata *, struct proc *)); 97 int nullfs_unmount __P((struct mount *, int, struct proc *)); 98 99 /* 100 * Mount null layer 101 */ 102 int 103 nullfs_mount(mp, path, data, ndp, p) 104 struct mount *mp; 105 const char *path; 106 void *data; 107 struct nameidata *ndp; 108 struct proc *p; 109 { 110 struct null_args args; 111 struct vnode *lowerrootvp, *vp; 112 struct null_mount *nmp; 113 struct layer_mount *lmp; 114 size_t size; 115 int error = 0; 116 117 #ifdef NULLFS_DIAGNOSTIC 118 printf("nullfs_mount(mp = %p)\n", mp); 119 #endif 120 121 /* 122 * Get argument 123 */ 124 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 125 if (error) 126 return (error); 127 128 /* 129 * Update only does export updating. 130 */ 131 if (mp->mnt_flag & MNT_UPDATE) { 132 lmp = MOUNTTOLAYERMOUNT(mp); 133 if (args.nulla_target == NULL) 134 return (vfs_export(mp, &lmp->layerm_export, 135 &args.la.export)); 136 else 137 return (EOPNOTSUPP); 138 } 139 140 /* 141 * Find lower node 142 */ 143 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, 144 UIO_USERSPACE, args.la.target, p); 145 if ((error = namei(ndp)) != 0) 146 return (error); 147 148 /* 149 * Sanity check on lower vnode 150 */ 151 lowerrootvp = ndp->ni_vp; 152 153 /* 154 * First cut at fixing up upper mount point 155 */ 156 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 157 M_UFSMNT, M_WAITOK); /* XXX */ 158 memset((caddr_t)nmp, 0, sizeof(struct null_mount)); 159 160 mp->mnt_data = (qaddr_t) nmp; 161 nmp->nullm_vfs = lowerrootvp->v_mount; 162 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 163 mp->mnt_flag |= MNT_LOCAL; 164 165 /* 166 * Make sure that the mount point is sufficiently initialized 167 * that the node create call will work. 168 */ 169 vfs_getnewfsid(mp); 170 171 nmp->nullm_size = sizeof(struct null_node); 172 nmp->nullm_tag = VT_NULL; 173 nmp->nullm_bypass = layer_bypass; 174 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 175 nmp->nullm_vnodeop_p = null_vnodeop_p; 176 simple_lock_init(&nmp->nullm_hashlock); 177 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, M_CACHE, 178 M_WAITOK, &nmp->nullm_node_hash); 179 180 /* 181 * Fix up null node for root vnode 182 */ 183 error = layer_node_create(mp, lowerrootvp, &vp); 184 /* 185 * Make sure the fixup worked 186 */ 187 if (error) { 188 vput(lowerrootvp); 189 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 190 free(nmp, M_UFSMNT); /* XXX */ 191 return (error); 192 } 193 /* 194 * Unlock the node 195 */ 196 VOP_UNLOCK(vp, 0); 197 198 /* 199 * Keep a held reference to the root vnode. 200 * It is vrele'd in nullfs_unmount. 201 */ 202 vp->v_flag |= VROOT; 203 nmp->nullm_rootvp = vp; 204 205 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 206 memset(mp->mnt_stat.f_mntonname + size, 0, MNAMELEN - size); 207 (void) copyinstr(args.la.target, mp->mnt_stat.f_mntfromname, 208 MNAMELEN - 1, &size); 209 memset(mp->mnt_stat.f_mntfromname + size, 0, MNAMELEN - size); 210 #ifdef NULLFS_DIAGNOSTIC 211 printf("nullfs_mount: lower %s, alias at %s\n", 212 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 213 #endif 214 return (0); 215 } 216 217 /* 218 * Free reference to null layer 219 */ 220 int 221 nullfs_unmount(mp, mntflags, p) 222 struct mount *mp; 223 int mntflags; 224 struct proc *p; 225 { 226 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 227 struct vnode *null_rootvp = nmp->nullm_rootvp; 228 int error; 229 int flags = 0; 230 231 #ifdef NULLFS_DIAGNOSTIC 232 printf("nullfs_unmount(mp = %p)\n", mp); 233 #endif 234 235 if (mntflags & MNT_FORCE) 236 flags |= FORCECLOSE; 237 238 /* 239 * Clear out buffer cache. I don't think we 240 * ever get anything cached at this level at the 241 * moment, but who knows... 242 */ 243 #if 0 244 mntflushbuf(mp, 0); 245 if (mntinvalbuf(mp, 1)) 246 return (EBUSY); 247 #endif 248 if (null_rootvp->v_usecount > 1) 249 return (EBUSY); 250 if ((error = vflush(mp, null_rootvp, flags)) != 0) 251 return (error); 252 253 #ifdef NULLFS_DIAGNOSTIC 254 vprint("alias root of lower", null_rootvp); 255 #endif 256 /* 257 * Release reference on underlying root vnode 258 */ 259 vrele(null_rootvp); 260 261 /* 262 * And blow it away for future re-use 263 */ 264 vgone(null_rootvp); 265 266 /* 267 * Finally, throw away the null_mount structure 268 */ 269 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 270 free(mp->mnt_data, M_UFSMNT); /* XXX */ 271 mp->mnt_data = NULL; 272 return (0); 273 } 274 275 extern const struct vnodeopv_desc null_vnodeop_opv_desc; 276 277 const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 278 &null_vnodeop_opv_desc, 279 NULL, 280 }; 281 282 struct vfsops nullfs_vfsops = { 283 MOUNT_NULL, 284 nullfs_mount, 285 layerfs_start, 286 nullfs_unmount, 287 layerfs_root, 288 layerfs_quotactl, 289 layerfs_statfs, 290 layerfs_sync, 291 layerfs_vget, 292 layerfs_fhtovp, 293 layerfs_vptofh, 294 layerfs_init, 295 NULL, 296 layerfs_done, 297 layerfs_sysctl, 298 NULL, /* vfs_mountroot */ 299 layerfs_checkexp, 300 nullfs_vnodeopv_descs, 301 }; 302