null_vfsops.c revision 1.77.12.1
1 /* $NetBSD: null_vfsops.c,v 1.77.12.1 2014/04/28 16:03:15 sborrill 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 1.77.12.1 2014/04/28 16:03:15 sborrill 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, NULL); 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(mp, path, data, data_len) 104 struct mount *mp; 105 const char *path; 106 void *data; 107 size_t *data_len; 108 { 109 struct lwp *l = curlwp; 110 struct nameidata nd; 111 struct null_args *args = data; 112 struct vnode *lowerrootvp, *vp; 113 struct null_mount *nmp; 114 struct layer_mount *lmp; 115 int error = 0; 116 117 #ifdef NULLFS_DIAGNOSTIC 118 printf("nullfs_mount(mp = %p)\n", mp); 119 #endif 120 121 if (args == NULL) 122 return EINVAL; 123 if (*data_len < sizeof *args) 124 return EINVAL; 125 126 if (mp->mnt_flag & MNT_GETARGS) { 127 lmp = MOUNTTOLAYERMOUNT(mp); 128 if (lmp == NULL) 129 return EIO; 130 args->la.target = NULL; 131 *data_len = sizeof *args; 132 return 0; 133 } 134 135 /* 136 * Update is not supported 137 */ 138 if (mp->mnt_flag & MNT_UPDATE) 139 return EOPNOTSUPP; 140 141 /* 142 * Find lower node 143 */ 144 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, UIO_USERSPACE, args->la.target); 145 if ((error = namei(&nd)) != 0) 146 return (error); 147 148 /* 149 * Sanity check on lower vnode 150 */ 151 lowerrootvp = nd.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(nmp, 0, sizeof(struct null_mount)); 159 160 mp->mnt_data = 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 mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE); 177 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, true, 178 &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, HASH_LIST, 190 nmp->nullm_node_hash); 191 free(nmp, M_UFSMNT); /* XXX */ 192 return (error); 193 } 194 /* 195 * Keep a held reference to the root vnode. 196 * It is vrele'd in nullfs_unmount. 197 */ 198 vp->v_vflag |= VV_ROOT; 199 nmp->nullm_rootvp = vp; 200 201 /* We don't need kernel_lock. */ 202 mp->mnt_iflag |= IMNT_MPSAFE; 203 204 /* 205 * Unlock the node 206 */ 207 VOP_UNLOCK(vp, 0); 208 209 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 210 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 211 #ifdef NULLFS_DIAGNOSTIC 212 printf("nullfs_mount: lower %s, alias at %s\n", 213 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 214 #endif 215 return error; 216 } 217 218 /* 219 * Free reference to null layer 220 */ 221 int 222 nullfs_unmount(struct mount *mp, int mntflags) 223 { 224 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 225 struct vnode *null_rootvp = nmp->nullm_rootvp; 226 int error; 227 int flags = 0; 228 229 #ifdef NULLFS_DIAGNOSTIC 230 printf("nullfs_unmount(mp = %p)\n", mp); 231 #endif 232 233 if (mntflags & MNT_FORCE) 234 flags |= FORCECLOSE; 235 236 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 237 return (EBUSY); 238 if ((error = vflush(mp, null_rootvp, flags)) != 0) 239 return (error); 240 241 #ifdef NULLFS_DIAGNOSTIC 242 vprint("alias root of lower", null_rootvp); 243 #endif 244 /* 245 * Blow it away for future re-use 246 */ 247 vgone(null_rootvp); 248 249 /* 250 * Finally, throw away the null_mount structure 251 */ 252 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash); 253 mutex_destroy(&nmp->nullm_hashlock); 254 free(mp->mnt_data, M_UFSMNT); /* XXX */ 255 mp->mnt_data = NULL; 256 return (0); 257 } 258 259 extern const struct vnodeopv_desc null_vnodeop_opv_desc; 260 261 const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 262 &null_vnodeop_opv_desc, 263 NULL, 264 }; 265 266 struct vfsops nullfs_vfsops = { 267 MOUNT_NULL, 268 sizeof (struct null_args), 269 nullfs_mount, 270 layerfs_start, 271 nullfs_unmount, 272 layerfs_root, 273 layerfs_quotactl, 274 layerfs_statvfs, 275 layerfs_sync, 276 layerfs_vget, 277 layerfs_fhtovp, 278 layerfs_vptofh, 279 layerfs_init, 280 NULL, 281 layerfs_done, 282 NULL, /* vfs_mountroot */ 283 layerfs_snapshot, 284 vfs_stdextattrctl, 285 (void *)eopnotsupp, /* vfs_suspendctl */ 286 layerfs_renamelock_enter, 287 layerfs_renamelock_exit, 288 (void *)eopnotsupp, 289 nullfs_vnodeopv_descs, 290 0, 291 { NULL, NULL }, 292 }; 293 294 static int 295 nullfs_modcmd(modcmd_t cmd, void *arg) 296 { 297 int error; 298 299 switch (cmd) { 300 case MODULE_CMD_INIT: 301 error = vfs_attach(&nullfs_vfsops); 302 if (error != 0) 303 break; 304 sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, 305 CTLFLAG_PERMANENT, 306 CTLTYPE_NODE, "vfs", NULL, 307 NULL, 0, NULL, 0, 308 CTL_VFS, CTL_EOL); 309 sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, 310 CTLFLAG_PERMANENT, 311 CTLTYPE_NODE, "null", 312 SYSCTL_DESCR("Loopback file system"), 313 NULL, 0, NULL, 0, 314 CTL_VFS, 9, CTL_EOL); 315 /* 316 * XXX the "9" above could be dynamic, thereby eliminating 317 * one more instance of the "number to vfs" mapping problem, 318 * but "9" is the order as taken from sys/mount.h 319 */ 320 break; 321 case MODULE_CMD_FINI: 322 error = vfs_detach(&nullfs_vfsops); 323 if (error != 0) 324 break; 325 sysctl_teardown(&nullfs_sysctl_log); 326 break; 327 default: 328 error = ENOTTY; 329 break; 330 } 331 332 return error; 333 } 334
Indexes created Tue Sep 30 20:09:53 GMT 2025