null_vfsops.c revision 1.69
1 /* $NetBSD: null_vfsops.c,v 1.69 2007/10/10 20:42:29 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 1.69 2007/10/10 20:42:29 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 89 #include <miscfs/nullfs/null.h> 90 #include <miscfs/genfs/layer_extern.h> 91 92 VFS_PROTOS(nullfs); 93 94 /* 95 * Mount null layer 96 */ 97 int 98 nullfs_mount(mp, path, data, data_len, l) 99 struct mount *mp; 100 const char *path; 101 void *data; 102 size_t *data_len; 103 struct lwp *l; 104 { 105 struct nameidata nd; 106 struct null_args *args = data; 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 (*data_len < sizeof *args) 117 return EINVAL; 118 119 if (mp->mnt_flag & MNT_GETARGS) { 120 lmp = MOUNTTOLAYERMOUNT(mp); 121 if (lmp == NULL) 122 return EIO; 123 args->la.target = NULL; 124 *data_len = sizeof *args; 125 return 0; 126 } 127 128 /* 129 * Update is not supported 130 */ 131 if (mp->mnt_flag & MNT_UPDATE) 132 return EOPNOTSUPP; 133 134 /* 135 * Find lower node 136 */ 137 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, 138 UIO_USERSPACE, args->la.target, l); 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, M_CACHE, 172 M_WAITOK, &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, M_CACHE); 184 free(nmp, M_UFSMNT); /* XXX */ 185 return (error); 186 } 187 /* 188 * Unlock the node 189 */ 190 vp->v_vflag |= VV_ROOT; 191 VOP_UNLOCK(vp, 0); 192 193 /* 194 * Keep a held reference to the root vnode. 195 * It is vrele'd in nullfs_unmount. 196 */ 197 nmp->nullm_rootvp = vp; 198 199 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 200 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 201 #ifdef NULLFS_DIAGNOSTIC 202 printf("nullfs_mount: lower %s, alias at %s\n", 203 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 204 #endif 205 return error; 206 } 207 208 /* 209 * Free reference to null layer 210 */ 211 int 212 nullfs_unmount(struct mount *mp, int mntflags, struct lwp *l) 213 { 214 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 215 struct vnode *null_rootvp = nmp->nullm_rootvp; 216 int error; 217 int flags = 0; 218 219 #ifdef NULLFS_DIAGNOSTIC 220 printf("nullfs_unmount(mp = %p)\n", mp); 221 #endif 222 223 if (mntflags & MNT_FORCE) 224 flags |= FORCECLOSE; 225 226 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 227 return (EBUSY); 228 if ((error = vflush(mp, null_rootvp, flags)) != 0) 229 return (error); 230 231 #ifdef NULLFS_DIAGNOSTIC 232 vprint("alias root of lower", null_rootvp); 233 #endif 234 /* 235 * Release reference on underlying root vnode 236 */ 237 vrele(null_rootvp); 238 239 /* 240 * And blow it away for future re-use 241 */ 242 vgone(null_rootvp); 243 244 /* 245 * Finally, throw away the null_mount structure 246 */ 247 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 248 mutex_destroy(&nmp->nullm_hashlock); 249 free(mp->mnt_data, M_UFSMNT); /* XXX */ 250 mp->mnt_data = NULL; 251 return (0); 252 } 253 254 SYSCTL_SETUP(sysctl_vfs_null_setup, "sysctl vfs.null subtree setup") 255 { 256 257 sysctl_createv(clog, 0, NULL, NULL, 258 CTLFLAG_PERMANENT, 259 CTLTYPE_NODE, "vfs", NULL, 260 NULL, 0, NULL, 0, 261 CTL_VFS, CTL_EOL); 262 sysctl_createv(clog, 0, NULL, NULL, 263 CTLFLAG_PERMANENT, 264 CTLTYPE_NODE, "null", 265 SYSCTL_DESCR("Loopback file system"), 266 NULL, 0, NULL, 0, 267 CTL_VFS, 9, CTL_EOL); 268 /* 269 * XXX the "9" above could be dynamic, thereby eliminating one 270 * more instance of the "number to vfs" mapping problem, but 271 * "9" is the order as taken from sys/mount.h 272 */ 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 sizeof (struct null_args), 285 nullfs_mount, 286 layerfs_start, 287 nullfs_unmount, 288 layerfs_root, 289 layerfs_quotactl, 290 layerfs_statvfs, 291 layerfs_sync, 292 layerfs_vget, 293 layerfs_fhtovp, 294 layerfs_vptofh, 295 layerfs_init, 296 NULL, 297 layerfs_done, 298 NULL, /* vfs_mountroot */ 299 layerfs_snapshot, 300 vfs_stdextattrctl, 301 (void *)eopnotsupp, /* vfs_suspendctl */ 302 nullfs_vnodeopv_descs, 303 0, 304 { NULL, NULL }, 305 }; 306 VFS_ATTACH(nullfs_vfsops); 307
Indexes created Thu Sep 25 16:09:42 GMT 2025