1 /* $NetBSD: null_vfsops.c,v 1.79 2009/03/14 15:36:22 dsl 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 1.79 2009/03/14 15:36:22 dsl Exp $"); 78 79 #include <sys/param.h> 80 #include <sys/systm.h> 81 #include <sys/sysctl.h> 82 #include <sys/time.h> 83 #include <sys/proc.h> 84 #include <sys/vnode.h> 85 #include <sys/mount.h> 86 #include <sys/namei.h> 87 #include <sys/malloc.h> 88 #include <sys/module.h> 89 90 #include <miscfs/nullfs/null.h> 91 #include <miscfs/genfs/layer_extern.h> 92 93 MODULE(MODULE_CLASS_VFS, nullfs, "layerfs"); 94 95 VFS_PROTOS(nullfs); 96 97 static struct sysctllog *nullfs_sysctl_log; 98 99 /* 100 * Mount null layer 101 */ 102 int 103 nullfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 104 { 105 struct lwp *l = curlwp; 106 struct nameidata nd; 107 struct null_args *args = data; 108 struct vnode *lowerrootvp, *vp; 109 struct null_mount *nmp; 110 struct layer_mount *lmp; 111 int error = 0; 112 113 #ifdef NULLFS_DIAGNOSTIC 114 printf("nullfs_mount(mp = %p)\n", mp); 115 #endif 116 117 if (*data_len < sizeof *args) 118 return EINVAL; 119 120 if (mp->mnt_flag & MNT_GETARGS) { 121 lmp = MOUNTTOLAYERMOUNT(mp); 122 if (lmp == NULL) 123 return EIO; 124 args->la.target = NULL; 125 *data_len = sizeof *args; 126 return 0; 127 } 128 129 /* 130 * Update is not supported 131 */ 132 if (mp->mnt_flag & MNT_UPDATE) 133 return EOPNOTSUPP; 134 135 /* 136 * Find lower node 137 */ 138 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, UIO_USERSPACE, args->la.target); 139 if ((error = namei(&nd)) != 0) 140 return (error); 141 142 /* 143 * Sanity check on lower vnode 144 */ 145 lowerrootvp = nd.ni_vp; 146 147 /* 148 * First cut at fixing up upper mount point 149 */ 150 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 151 M_UFSMNT, M_WAITOK); /* XXX */ 152 memset(nmp, 0, sizeof(struct null_mount)); 153 154 mp->mnt_data = nmp; 155 nmp->nullm_vfs = lowerrootvp->v_mount; 156 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 157 mp->mnt_flag |= MNT_LOCAL; 158 159 /* 160 * Make sure that the mount point is sufficiently initialized 161 * that the node create call will work. 162 */ 163 vfs_getnewfsid(mp); 164 165 nmp->nullm_size = sizeof(struct null_node); 166 nmp->nullm_tag = VT_NULL; 167 nmp->nullm_bypass = layer_bypass; 168 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 169 nmp->nullm_vnodeop_p = null_vnodeop_p; 170 mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE); 171 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, true, 172 &nmp->nullm_node_hash); 173 174 /* 175 * Fix up null node for root vnode 176 */ 177 error = layer_node_create(mp, lowerrootvp, &vp); 178 /* 179 * Make sure the fixup worked 180 */ 181 if (error) { 182 vput(lowerrootvp); 183 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, 184 nmp->nullm_node_hash); 185 free(nmp, M_UFSMNT); /* XXX */ 186 return (error); 187 } 188 /* 189 * Keep a held reference to the root vnode. 190 * It is vrele'd in nullfs_unmount. 191 */ 192 vp->v_vflag |= VV_ROOT; 193 nmp->nullm_rootvp = vp; 194 195 /* We don't need kernel_lock. */ 196 mp->mnt_iflag |= IMNT_MPSAFE; 197 198 /* 199 * Unlock the node 200 */ 201 VOP_UNLOCK(vp, 0); 202 203 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 204 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 205 #ifdef NULLFS_DIAGNOSTIC 206 printf("nullfs_mount: lower %s, alias at %s\n", 207 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 208 #endif 209 return error; 210 } 211 212 /* 213 * Free reference to null layer 214 */ 215 int 216 nullfs_unmount(struct mount *mp, int mntflags) 217 { 218 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 219 struct vnode *null_rootvp = nmp->nullm_rootvp; 220 int error; 221 int flags = 0; 222 223 #ifdef NULLFS_DIAGNOSTIC 224 printf("nullfs_unmount(mp = %p)\n", mp); 225 #endif 226 227 if (mntflags & MNT_FORCE) 228 flags |= FORCECLOSE; 229 230 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 231 return (EBUSY); 232 if ((error = vflush(mp, null_rootvp, flags)) != 0) 233 return (error); 234 235 #ifdef NULLFS_DIAGNOSTIC 236 vprint("alias root of lower", null_rootvp); 237 #endif 238 /* 239 * Blow it away for future re-use 240 */ 241 vgone(null_rootvp); 242 243 /* 244 * Finally, throw away the null_mount structure 245 */ 246 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash); 247 mutex_destroy(&nmp->nullm_hashlock); 248 free(mp->mnt_data, M_UFSMNT); /* XXX */ 249 mp->mnt_data = NULL; 250 return (0); 251 } 252 253 extern const struct vnodeopv_desc null_vnodeop_opv_desc; 254 255 const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 256 &null_vnodeop_opv_desc, 257 NULL, 258 }; 259 260 struct vfsops nullfs_vfsops = { 261 MOUNT_NULL, 262 sizeof (struct null_args), 263 nullfs_mount, 264 layerfs_start, 265 nullfs_unmount, 266 layerfs_root, 267 layerfs_quotactl, 268 layerfs_statvfs, 269 layerfs_sync, 270 layerfs_vget, 271 layerfs_fhtovp, 272 layerfs_vptofh, 273 layerfs_init, 274 NULL, 275 layerfs_done, 276 NULL, /* vfs_mountroot */ 277 layerfs_snapshot, 278 vfs_stdextattrctl, 279 (void *)eopnotsupp, /* vfs_suspendctl */ 280 layerfs_renamelock_enter, 281 layerfs_renamelock_exit, 282 (void *)eopnotsupp, 283 nullfs_vnodeopv_descs, 284 0, 285 { NULL, NULL }, 286 }; 287 288 static int 289 nullfs_modcmd(modcmd_t cmd, void *arg) 290 { 291 int error; 292 293 switch (cmd) { 294 case MODULE_CMD_INIT: 295 error = vfs_attach(&nullfs_vfsops); 296 if (error != 0) 297 break; 298 sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, 299 CTLFLAG_PERMANENT, 300 CTLTYPE_NODE, "vfs", NULL, 301 NULL, 0, NULL, 0, 302 CTL_VFS, CTL_EOL); 303 sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, 304 CTLFLAG_PERMANENT, 305 CTLTYPE_NODE, "null", 306 SYSCTL_DESCR("Loopback file system"), 307 NULL, 0, NULL, 0, 308 CTL_VFS, 9, CTL_EOL); 309 /* 310 * XXX the "9" above could be dynamic, thereby eliminating 311 * one more instance of the "number to vfs" mapping problem, 312 * but "9" is the order as taken from sys/mount.h 313 */ 314 break; 315 case MODULE_CMD_FINI: 316 error = vfs_detach(&nullfs_vfsops); 317 if (error != 0) 318 break; 319 sysctl_teardown(&nullfs_sysctl_log); 320 break; 321 default: 322 error = ENOTTY; 323 break; 324 } 325 326 return error; 327 } 328