null_vfsops.c revision 1.76
1 /* $NetBSD: null_vfsops.c,v 1.76 2008/05/10 02:26:09 rumble 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 1.76 2008/05/10 02:26:09 rumble 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 /* 98 * Mount null layer 99 */ 100 int 101 nullfs_mount(mp, path, data, data_len) 102 struct mount *mp; 103 const char *path; 104 void *data; 105 size_t *data_len; 106 { 107 struct lwp *l = curlwp; 108 struct nameidata nd; 109 struct null_args *args = data; 110 struct vnode *lowerrootvp, *vp; 111 struct null_mount *nmp; 112 struct layer_mount *lmp; 113 int error = 0; 114 115 #ifdef NULLFS_DIAGNOSTIC 116 printf("nullfs_mount(mp = %p)\n", mp); 117 #endif 118 119 if (*data_len < sizeof *args) 120 return EINVAL; 121 122 if (mp->mnt_flag & MNT_GETARGS) { 123 lmp = MOUNTTOLAYERMOUNT(mp); 124 if (lmp == NULL) 125 return EIO; 126 args->la.target = NULL; 127 *data_len = sizeof *args; 128 return 0; 129 } 130 131 /* 132 * Update is not supported 133 */ 134 if (mp->mnt_flag & MNT_UPDATE) 135 return EOPNOTSUPP; 136 137 /* 138 * Find lower node 139 */ 140 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, UIO_USERSPACE, args->la.target); 141 if ((error = namei(&nd)) != 0) 142 return (error); 143 144 /* 145 * Sanity check on lower vnode 146 */ 147 lowerrootvp = nd.ni_vp; 148 149 /* 150 * First cut at fixing up upper mount point 151 */ 152 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 153 M_UFSMNT, M_WAITOK); /* XXX */ 154 memset(nmp, 0, sizeof(struct null_mount)); 155 156 mp->mnt_data = nmp; 157 nmp->nullm_vfs = lowerrootvp->v_mount; 158 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 159 mp->mnt_flag |= MNT_LOCAL; 160 161 /* 162 * Make sure that the mount point is sufficiently initialized 163 * that the node create call will work. 164 */ 165 vfs_getnewfsid(mp); 166 167 nmp->nullm_size = sizeof(struct null_node); 168 nmp->nullm_tag = VT_NULL; 169 nmp->nullm_bypass = layer_bypass; 170 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 171 nmp->nullm_vnodeop_p = null_vnodeop_p; 172 mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE); 173 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, true, 174 &nmp->nullm_node_hash); 175 176 /* 177 * Fix up null node for root vnode 178 */ 179 error = layer_node_create(mp, lowerrootvp, &vp); 180 /* 181 * Make sure the fixup worked 182 */ 183 if (error) { 184 vput(lowerrootvp); 185 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, 186 nmp->nullm_node_hash); 187 free(nmp, M_UFSMNT); /* XXX */ 188 return (error); 189 } 190 /* 191 * Keep a held reference to the root vnode. 192 * It is vrele'd in nullfs_unmount. 193 */ 194 vp->v_vflag |= VV_ROOT; 195 nmp->nullm_rootvp = vp; 196 197 /* We don't need kernel_lock. */ 198 mp->mnt_iflag |= IMNT_MPSAFE; 199 200 /* 201 * Unlock the node 202 */ 203 VOP_UNLOCK(vp, 0); 204 205 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 206 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 207 #ifdef NULLFS_DIAGNOSTIC 208 printf("nullfs_mount: lower %s, alias at %s\n", 209 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 210 #endif 211 return error; 212 } 213 214 /* 215 * Free reference to null layer 216 */ 217 int 218 nullfs_unmount(struct mount *mp, int mntflags) 219 { 220 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 221 struct vnode *null_rootvp = nmp->nullm_rootvp; 222 int error; 223 int flags = 0; 224 225 #ifdef NULLFS_DIAGNOSTIC 226 printf("nullfs_unmount(mp = %p)\n", mp); 227 #endif 228 229 if (mntflags & MNT_FORCE) 230 flags |= FORCECLOSE; 231 232 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 233 return (EBUSY); 234 if ((error = vflush(mp, null_rootvp, flags)) != 0) 235 return (error); 236 237 #ifdef NULLFS_DIAGNOSTIC 238 vprint("alias root of lower", null_rootvp); 239 #endif 240 /* 241 * Blow it away for future re-use 242 */ 243 vgone(null_rootvp); 244 245 /* 246 * Finally, throw away the null_mount structure 247 */ 248 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash); 249 mutex_destroy(&nmp->nullm_hashlock); 250 free(mp->mnt_data, M_UFSMNT); /* XXX */ 251 mp->mnt_data = NULL; 252 return (0); 253 } 254 255 SYSCTL_SETUP(sysctl_vfs_null_setup, "sysctl vfs.null subtree setup") 256 { 257 258 sysctl_createv(clog, 0, NULL, NULL, 259 CTLFLAG_PERMANENT, 260 CTLTYPE_NODE, "vfs", NULL, 261 NULL, 0, NULL, 0, 262 CTL_VFS, CTL_EOL); 263 sysctl_createv(clog, 0, NULL, NULL, 264 CTLFLAG_PERMANENT, 265 CTLTYPE_NODE, "null", 266 SYSCTL_DESCR("Loopback file system"), 267 NULL, 0, NULL, 0, 268 CTL_VFS, 9, CTL_EOL); 269 /* 270 * XXX the "9" above could be dynamic, thereby eliminating one 271 * more instance of the "number to vfs" mapping problem, but 272 * "9" is the order as taken from sys/mount.h 273 */ 274 } 275 276 extern const struct vnodeopv_desc null_vnodeop_opv_desc; 277 278 const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 279 &null_vnodeop_opv_desc, 280 NULL, 281 }; 282 283 struct vfsops nullfs_vfsops = { 284 MOUNT_NULL, 285 sizeof (struct null_args), 286 nullfs_mount, 287 layerfs_start, 288 nullfs_unmount, 289 layerfs_root, 290 layerfs_quotactl, 291 layerfs_statvfs, 292 layerfs_sync, 293 layerfs_vget, 294 layerfs_fhtovp, 295 layerfs_vptofh, 296 layerfs_init, 297 NULL, 298 layerfs_done, 299 NULL, /* vfs_mountroot */ 300 layerfs_snapshot, 301 vfs_stdextattrctl, 302 (void *)eopnotsupp, /* vfs_suspendctl */ 303 layerfs_renamelock_enter, 304 layerfs_renamelock_exit, 305 (void *)eopnotsupp, 306 nullfs_vnodeopv_descs, 307 0, 308 { NULL, NULL }, 309 }; 310 311 static int 312 nullfs_modcmd(modcmd_t cmd, void *arg) 313 { 314 315 switch (cmd) { 316 case MODULE_CMD_INIT: 317 return vfs_attach(&nullfs_vfsops); 318 case MODULE_CMD_FINI: 319 return vfs_detach(&nullfs_vfsops); 320 default: 321 return ENOTTY; 322 } 323 } 324
Indexes created Thu Sep 25 15:09:46 GMT 2025