null_vfsops.c revision 1.65
1 /* $NetBSD: null_vfsops.c,v 1.65 2007/07/12 19:35:34 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 1.65 2007/07/12 19:35:34 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 89 #include <miscfs/nullfs/null.h> 90 #include <miscfs/genfs/layer_extern.h> 91 92 int nullfs_mount(struct mount *, const char *, void *, size_t *, 93 struct nameidata *, struct lwp *); 94 int nullfs_unmount(struct mount *, int, struct lwp *); 95 96 /* 97 * Mount null layer 98 */ 99 int 100 nullfs_mount(mp, path, data, data_len, ndp, l) 101 struct mount *mp; 102 const char *path; 103 void *data; 104 size_t *data_len; 105 struct nameidata *ndp; 106 struct lwp *l; 107 { 108 struct null_args *args = data; 109 struct vnode *lowerrootvp, *vp; 110 struct null_mount *nmp; 111 struct layer_mount *lmp; 112 int error = 0; 113 114 #ifdef NULLFS_DIAGNOSTIC 115 printf("nullfs_mount(mp = %p)\n", mp); 116 #endif 117 118 if (*data_len < sizeof *args) 119 return EINVAL; 120 121 if (mp->mnt_flag & MNT_GETARGS) { 122 lmp = MOUNTTOLAYERMOUNT(mp); 123 if (lmp == NULL) 124 return EIO; 125 args->la.target = NULL; 126 *data_len = sizeof *args; 127 return 0; 128 } 129 130 /* 131 * Update is not supported 132 */ 133 if (mp->mnt_flag & MNT_UPDATE) 134 return EOPNOTSUPP; 135 136 /* 137 * Find lower node 138 */ 139 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, 140 UIO_USERSPACE, args->la.target, l); 141 if ((error = namei(ndp)) != 0) 142 return (error); 143 144 /* 145 * Sanity check on lower vnode 146 */ 147 lowerrootvp = ndp->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 simple_lock_init(&nmp->nullm_hashlock); 173 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, M_CACHE, 174 M_WAITOK, &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, M_CACHE); 186 free(nmp, M_UFSMNT); /* XXX */ 187 return (error); 188 } 189 /* 190 * Unlock the node 191 */ 192 VOP_UNLOCK(vp, 0); 193 194 /* 195 * Keep a held reference to the root vnode. 196 * It is vrele'd in nullfs_unmount. 197 */ 198 vp->v_flag |= VROOT; 199 nmp->nullm_rootvp = vp; 200 201 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 202 UIO_USERSPACE, mp, l); 203 #ifdef NULLFS_DIAGNOSTIC 204 printf("nullfs_mount: lower %s, alias at %s\n", 205 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 206 #endif 207 return error; 208 } 209 210 /* 211 * Free reference to null layer 212 */ 213 int 214 nullfs_unmount(struct mount *mp, int mntflags, struct lwp *l) 215 { 216 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 217 struct vnode *null_rootvp = nmp->nullm_rootvp; 218 int error; 219 int flags = 0; 220 221 #ifdef NULLFS_DIAGNOSTIC 222 printf("nullfs_unmount(mp = %p)\n", mp); 223 #endif 224 225 if (mntflags & MNT_FORCE) 226 flags |= FORCECLOSE; 227 228 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 229 return (EBUSY); 230 if ((error = vflush(mp, null_rootvp, flags)) != 0) 231 return (error); 232 233 #ifdef NULLFS_DIAGNOSTIC 234 vprint("alias root of lower", null_rootvp); 235 #endif 236 /* 237 * Release reference on underlying root vnode 238 */ 239 vrele(null_rootvp); 240 241 /* 242 * And blow it away for future re-use 243 */ 244 vgone(null_rootvp); 245 246 /* 247 * Finally, throw away the null_mount structure 248 */ 249 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 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 vfs_stdsuspendctl, 303 nullfs_vnodeopv_descs, 304 0, 305 { NULL, NULL }, 306 }; 307 VFS_ATTACH(nullfs_vfsops); 308
Indexes created Thu Sep 25 16:09:42 GMT 2025