null_vfsops.c revision 1.77
1 /* $NetBSD: null_vfsops.c,v 1.77 2008/06/24 11:25:05 ad 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 2008/06/24 11:25:05 ad 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 (*data_len < sizeof *args) 122 return EINVAL; 123 124 if (mp->mnt_flag & MNT_GETARGS) { 125 lmp = MOUNTTOLAYERMOUNT(mp); 126 if (lmp == NULL) 127 return EIO; 128 args->la.target = NULL; 129 *data_len = sizeof *args; 130 return 0; 131 } 132 133 /* 134 * Update is not supported 135 */ 136 if (mp->mnt_flag & MNT_UPDATE) 137 return EOPNOTSUPP; 138 139 /* 140 * Find lower node 141 */ 142 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, UIO_USERSPACE, args->la.target); 143 if ((error = namei(&nd)) != 0) 144 return (error); 145 146 /* 147 * Sanity check on lower vnode 148 */ 149 lowerrootvp = nd.ni_vp; 150 151 /* 152 * First cut at fixing up upper mount point 153 */ 154 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 155 M_UFSMNT, M_WAITOK); /* XXX */ 156 memset(nmp, 0, sizeof(struct null_mount)); 157 158 mp->mnt_data = nmp; 159 nmp->nullm_vfs = lowerrootvp->v_mount; 160 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 161 mp->mnt_flag |= MNT_LOCAL; 162 163 /* 164 * Make sure that the mount point is sufficiently initialized 165 * that the node create call will work. 166 */ 167 vfs_getnewfsid(mp); 168 169 nmp->nullm_size = sizeof(struct null_node); 170 nmp->nullm_tag = VT_NULL; 171 nmp->nullm_bypass = layer_bypass; 172 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 173 nmp->nullm_vnodeop_p = null_vnodeop_p; 174 mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE); 175 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, true, 176 &nmp->nullm_node_hash); 177 178 /* 179 * Fix up null node for root vnode 180 */ 181 error = layer_node_create(mp, lowerrootvp, &vp); 182 /* 183 * Make sure the fixup worked 184 */ 185 if (error) { 186 vput(lowerrootvp); 187 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, 188 nmp->nullm_node_hash); 189 free(nmp, M_UFSMNT); /* XXX */ 190 return (error); 191 } 192 /* 193 * Keep a held reference to the root vnode. 194 * It is vrele'd in nullfs_unmount. 195 */ 196 vp->v_vflag |= VV_ROOT; 197 nmp->nullm_rootvp = vp; 198 199 /* We don't need kernel_lock. */ 200 mp->mnt_iflag |= IMNT_MPSAFE; 201 202 /* 203 * Unlock the node 204 */ 205 VOP_UNLOCK(vp, 0); 206 207 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 208 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 209 #ifdef NULLFS_DIAGNOSTIC 210 printf("nullfs_mount: lower %s, alias at %s\n", 211 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 212 #endif 213 return error; 214 } 215 216 /* 217 * Free reference to null layer 218 */ 219 int 220 nullfs_unmount(struct mount *mp, int mntflags) 221 { 222 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 223 struct vnode *null_rootvp = nmp->nullm_rootvp; 224 int error; 225 int flags = 0; 226 227 #ifdef NULLFS_DIAGNOSTIC 228 printf("nullfs_unmount(mp = %p)\n", mp); 229 #endif 230 231 if (mntflags & MNT_FORCE) 232 flags |= FORCECLOSE; 233 234 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 235 return (EBUSY); 236 if ((error = vflush(mp, null_rootvp, flags)) != 0) 237 return (error); 238 239 #ifdef NULLFS_DIAGNOSTIC 240 vprint("alias root of lower", null_rootvp); 241 #endif 242 /* 243 * Blow it away for future re-use 244 */ 245 vgone(null_rootvp); 246 247 /* 248 * Finally, throw away the null_mount structure 249 */ 250 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash); 251 mutex_destroy(&nmp->nullm_hashlock); 252 free(mp->mnt_data, M_UFSMNT); /* XXX */ 253 mp->mnt_data = NULL; 254 return (0); 255 } 256 257 extern const struct vnodeopv_desc null_vnodeop_opv_desc; 258 259 const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 260 &null_vnodeop_opv_desc, 261 NULL, 262 }; 263 264 struct vfsops nullfs_vfsops = { 265 MOUNT_NULL, 266 sizeof (struct null_args), 267 nullfs_mount, 268 layerfs_start, 269 nullfs_unmount, 270 layerfs_root, 271 layerfs_quotactl, 272 layerfs_statvfs, 273 layerfs_sync, 274 layerfs_vget, 275 layerfs_fhtovp, 276 layerfs_vptofh, 277 layerfs_init, 278 NULL, 279 layerfs_done, 280 NULL, /* vfs_mountroot */ 281 layerfs_snapshot, 282 vfs_stdextattrctl, 283 (void *)eopnotsupp, /* vfs_suspendctl */ 284 layerfs_renamelock_enter, 285 layerfs_renamelock_exit, 286 (void *)eopnotsupp, 287 nullfs_vnodeopv_descs, 288 0, 289 { NULL, NULL }, 290 }; 291 292 static int 293 nullfs_modcmd(modcmd_t cmd, void *arg) 294 { 295 int error; 296 297 switch (cmd) { 298 case MODULE_CMD_INIT: 299 error = vfs_attach(&nullfs_vfsops); 300 if (error != 0) 301 break; 302 sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, 303 CTLFLAG_PERMANENT, 304 CTLTYPE_NODE, "vfs", NULL, 305 NULL, 0, NULL, 0, 306 CTL_VFS, CTL_EOL); 307 sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, 308 CTLFLAG_PERMANENT, 309 CTLTYPE_NODE, "null", 310 SYSCTL_DESCR("Loopback file system"), 311 NULL, 0, NULL, 0, 312 CTL_VFS, 9, CTL_EOL); 313 /* 314 * XXX the "9" above could be dynamic, thereby eliminating 315 * one more instance of the "number to vfs" mapping problem, 316 * but "9" is the order as taken from sys/mount.h 317 */ 318 break; 319 case MODULE_CMD_FINI: 320 error = vfs_detach(&nullfs_vfsops); 321 if (error != 0) 322 break; 323 sysctl_teardown(&nullfs_sysctl_log); 324 break; 325 default: 326 error = ENOTTY; 327 break; 328 } 329 330 return error; 331 } 332
Indexes created Thu Sep 25 15:09:46 GMT 2025