1 /* $NetBSD: null_vfsops.c,v 1.43 2003/08/07 16:32:38 agc 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. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp 67 * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 68 * @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95 69 */ 70 71 /* 72 * Null Layer 73 * (See null_vnops.c for a description of what this does.) 74 */ 75 76 #include <sys/cdefs.h> 77 __KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.43 2003/08/07 16:32:38 agc Exp $"); 78 79 #include <sys/param.h> 80 #include <sys/systm.h> 81 #include <sys/time.h> 82 #include <sys/proc.h> 83 #include <sys/vnode.h> 84 #include <sys/mount.h> 85 #include <sys/namei.h> 86 #include <sys/malloc.h> 87 88 #include <miscfs/nullfs/null.h> 89 #include <miscfs/genfs/layer_extern.h> 90 91 int nullfs_mount __P((struct mount *, const char *, void *, 92 struct nameidata *, struct proc *)); 93 int nullfs_unmount __P((struct mount *, int, struct proc *)); 94 95 /* 96 * Mount null layer 97 */ 98 int 99 nullfs_mount(mp, path, data, ndp, p) 100 struct mount *mp; 101 const char *path; 102 void *data; 103 struct nameidata *ndp; 104 struct proc *p; 105 { 106 struct null_args args; 107 struct vnode *lowerrootvp, *vp; 108 struct null_mount *nmp; 109 struct layer_mount *lmp; 110 int error = 0; 111 112 #ifdef NULLFS_DIAGNOSTIC 113 printf("nullfs_mount(mp = %p)\n", mp); 114 #endif 115 116 if (mp->mnt_flag & MNT_GETARGS) { 117 lmp = MOUNTTOLAYERMOUNT(mp); 118 if (lmp == NULL) 119 return EIO; 120 args.la.target = NULL; 121 vfs_showexport(mp, &args.la.export, &lmp->layerm_export); 122 return copyout(&args, data, sizeof(args)); 123 } 124 /* 125 * Get argument 126 */ 127 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 128 if (error) 129 return (error); 130 131 /* 132 * Update only does export updating. 133 */ 134 if (mp->mnt_flag & MNT_UPDATE) { 135 lmp = MOUNTTOLAYERMOUNT(mp); 136 if (args.nulla_target == NULL) 137 return (vfs_export(mp, &lmp->layerm_export, 138 &args.la.export)); 139 else 140 return (EOPNOTSUPP); 141 } 142 143 /* 144 * Find lower node 145 */ 146 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, 147 UIO_USERSPACE, args.la.target, p); 148 if ((error = namei(ndp)) != 0) 149 return (error); 150 151 /* 152 * Sanity check on lower vnode 153 */ 154 lowerrootvp = ndp->ni_vp; 155 156 /* 157 * First cut at fixing up upper mount point 158 */ 159 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 160 M_UFSMNT, M_WAITOK); /* XXX */ 161 memset((caddr_t)nmp, 0, sizeof(struct null_mount)); 162 163 mp->mnt_data = nmp; 164 nmp->nullm_vfs = lowerrootvp->v_mount; 165 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 166 mp->mnt_flag |= MNT_LOCAL; 167 168 /* 169 * Make sure that the mount point is sufficiently initialized 170 * that the node create call will work. 171 */ 172 vfs_getnewfsid(mp); 173 174 nmp->nullm_size = sizeof(struct null_node); 175 nmp->nullm_tag = VT_NULL; 176 nmp->nullm_bypass = layer_bypass; 177 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 178 nmp->nullm_vnodeop_p = null_vnodeop_p; 179 simple_lock_init(&nmp->nullm_hashlock); 180 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, M_CACHE, 181 M_WAITOK, &nmp->nullm_node_hash); 182 183 /* 184 * Fix up null node for root vnode 185 */ 186 error = layer_node_create(mp, lowerrootvp, &vp); 187 /* 188 * Make sure the fixup worked 189 */ 190 if (error) { 191 vput(lowerrootvp); 192 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 193 free(nmp, M_UFSMNT); /* XXX */ 194 return (error); 195 } 196 /* 197 * Unlock the node 198 */ 199 VOP_UNLOCK(vp, 0); 200 201 /* 202 * Keep a held reference to the root vnode. 203 * It is vrele'd in nullfs_unmount. 204 */ 205 vp->v_flag |= VROOT; 206 nmp->nullm_rootvp = vp; 207 208 error = set_statfs_info(path, UIO_USERSPACE, args.la.target, 209 UIO_USERSPACE, mp, p); 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 error; 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