1 /* $NetBSD: null_vfsops.c,v 1.61 2006/11/16 01:33:38 christos 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 1.61 2006/11/16 01:33:38 christos 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 *, 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, ndp, l) 101 struct mount *mp; 102 const char *path; 103 void *data; 104 struct nameidata *ndp; 105 struct lwp *l; 106 { 107 struct null_args args; 108 struct vnode *lowerrootvp, *vp; 109 struct null_mount *nmp; 110 struct layer_mount *lmp; 111 int error = 0; 112 113 #ifdef NULLFS_DIAGNOSTIC 114 printf("nullfs_mount(mp = %p)\n", mp); 115 #endif 116 117 if (mp->mnt_flag & MNT_GETARGS) { 118 lmp = MOUNTTOLAYERMOUNT(mp); 119 if (lmp == NULL) 120 return EIO; 121 args.la.target = NULL; 122 return copyout(&args, data, sizeof(args)); 123 } 124 /* 125 * Get argument 126 */ 127 error = copyin(data, &args, sizeof(struct null_args)); 128 if (error) 129 return (error); 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(ndp, LOOKUP, FOLLOW|LOCKLEAF, 141 UIO_USERSPACE, args.la.target, l); 142 if ((error = namei(ndp)) != 0) 143 return (error); 144 145 /* 146 * Sanity check on lower vnode 147 */ 148 lowerrootvp = ndp->ni_vp; 149 150 /* 151 * First cut at fixing up upper mount point 152 */ 153 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 154 M_UFSMNT, M_WAITOK); /* XXX */ 155 memset(nmp, 0, sizeof(struct null_mount)); 156 157 mp->mnt_data = nmp; 158 mp->mnt_leaf = lowerrootvp->v_mount->mnt_leaf; 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 simple_lock_init(&nmp->nullm_hashlock); 175 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, M_CACHE, 176 M_WAITOK, &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, M_CACHE); 188 free(nmp, M_UFSMNT); /* XXX */ 189 return (error); 190 } 191 /* 192 * Unlock the node 193 */ 194 VOP_UNLOCK(vp, 0); 195 196 /* 197 * Keep a held reference to the root vnode. 198 * It is vrele'd in nullfs_unmount. 199 */ 200 vp->v_flag |= VROOT; 201 nmp->nullm_rootvp = vp; 202 203 error = set_statvfs_info(path, UIO_USERSPACE, args.la.target, 204 UIO_USERSPACE, mp, l); 205 #ifdef NULLFS_DIAGNOSTIC 206 printf("nullfs_mount: lower %s, alias at %s\n", 207 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 208 #endif 209 return error; 210 } 211 212 /* 213 * Free reference to null layer 214 */ 215 int 216 nullfs_unmount(struct mount *mp, int mntflags, struct lwp *l) 217 { 218 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 219 struct vnode *null_rootvp = nmp->nullm_rootvp; 220 int error; 221 int flags = 0; 222 223 #ifdef NULLFS_DIAGNOSTIC 224 printf("nullfs_unmount(mp = %p)\n", mp); 225 #endif 226 227 if (mntflags & MNT_FORCE) 228 flags |= FORCECLOSE; 229 230 /* 231 * Clear out buffer cache. I don't think we 232 * ever get anything cached at this level at the 233 * moment, but who knows... 234 */ 235 #if 0 236 mntflushbuf(mp, 0); 237 if (mntinvalbuf(mp, 1)) 238 return (EBUSY); 239 #endif 240 if (null_rootvp->v_usecount > 1) 241 return (EBUSY); 242 if ((error = vflush(mp, null_rootvp, flags)) != 0) 243 return (error); 244 245 #ifdef NULLFS_DIAGNOSTIC 246 vprint("alias root of lower", null_rootvp); 247 #endif 248 /* 249 * Release reference on underlying root vnode 250 */ 251 vrele(null_rootvp); 252 253 /* 254 * And blow it away for future re-use 255 */ 256 vgone(null_rootvp); 257 258 /* 259 * Finally, throw away the null_mount structure 260 */ 261 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 262 free(mp->mnt_data, M_UFSMNT); /* XXX */ 263 mp->mnt_data = NULL; 264 return (0); 265 } 266 267 SYSCTL_SETUP(sysctl_vfs_null_setup, "sysctl vfs.null subtree setup") 268 { 269 270 sysctl_createv(clog, 0, NULL, NULL, 271 CTLFLAG_PERMANENT, 272 CTLTYPE_NODE, "vfs", NULL, 273 NULL, 0, NULL, 0, 274 CTL_VFS, CTL_EOL); 275 sysctl_createv(clog, 0, NULL, NULL, 276 CTLFLAG_PERMANENT, 277 CTLTYPE_NODE, "null", 278 SYSCTL_DESCR("Loopback file system"), 279 NULL, 0, NULL, 0, 280 CTL_VFS, 9, CTL_EOL); 281 /* 282 * XXX the "9" above could be dynamic, thereby eliminating one 283 * more instance of the "number to vfs" mapping problem, but 284 * "9" is the order as taken from sys/mount.h 285 */ 286 } 287 288 extern const struct vnodeopv_desc null_vnodeop_opv_desc; 289 290 const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 291 &null_vnodeop_opv_desc, 292 NULL, 293 }; 294 295 struct vfsops nullfs_vfsops = { 296 MOUNT_NULL, 297 nullfs_mount, 298 layerfs_start, 299 nullfs_unmount, 300 layerfs_root, 301 layerfs_quotactl, 302 layerfs_statvfs, 303 layerfs_sync, 304 layerfs_vget, 305 layerfs_fhtovp, 306 layerfs_vptofh, 307 layerfs_init, 308 NULL, 309 layerfs_done, 310 NULL, /* vfs_mountroot */ 311 layerfs_snapshot, 312 vfs_stdextattrctl, 313 nullfs_vnodeopv_descs, 314 0, 315 { NULL, NULL }, 316 }; 317 VFS_ATTACH(nullfs_vfsops); 318