null_vfsops.c revision 1.75
1/* $NetBSD: null_vfsops.c,v 1.75 2008/05/05 17:11:17 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 1.75 2008/05/05 17:11:17 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 92VFS_PROTOS(nullfs); 93 94/* 95 * Mount null layer 96 */ 97int 98nullfs_mount(mp, path, data, data_len) 99 struct mount *mp; 100 const char *path; 101 void *data; 102 size_t *data_len; 103{ 104 struct lwp *l = curlwp; 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, UIO_USERSPACE, args->la.target); 138 if ((error = namei(&nd)) != 0) 139 return (error); 140 141 /* 142 * Sanity check on lower vnode 143 */ 144 lowerrootvp = nd.ni_vp; 145 146 /* 147 * First cut at fixing up upper mount point 148 */ 149 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 150 M_UFSMNT, M_WAITOK); /* XXX */ 151 memset(nmp, 0, sizeof(struct null_mount)); 152 153 mp->mnt_data = nmp; 154 nmp->nullm_vfs = lowerrootvp->v_mount; 155 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 156 mp->mnt_flag |= MNT_LOCAL; 157 158 /* 159 * Make sure that the mount point is sufficiently initialized 160 * that the node create call will work. 161 */ 162 vfs_getnewfsid(mp); 163 164 nmp->nullm_size = sizeof(struct null_node); 165 nmp->nullm_tag = VT_NULL; 166 nmp->nullm_bypass = layer_bypass; 167 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 168 nmp->nullm_vnodeop_p = null_vnodeop_p; 169 mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE); 170 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, true, 171 &nmp->nullm_node_hash); 172 173 /* 174 * Fix up null node for root vnode 175 */ 176 error = layer_node_create(mp, lowerrootvp, &vp); 177 /* 178 * Make sure the fixup worked 179 */ 180 if (error) { 181 vput(lowerrootvp); 182 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, 183 nmp->nullm_node_hash); 184 free(nmp, M_UFSMNT); /* XXX */ 185 return (error); 186 } 187 /* 188 * Keep a held reference to the root vnode. 189 * It is vrele'd in nullfs_unmount. 190 */ 191 vp->v_vflag |= VV_ROOT; 192 nmp->nullm_rootvp = vp; 193 194 /* We don't need kernel_lock. */ 195 mp->mnt_iflag |= IMNT_MPSAFE; 196 197 /* 198 * Unlock the node 199 */ 200 VOP_UNLOCK(vp, 0); 201 202 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 203 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 204#ifdef NULLFS_DIAGNOSTIC 205 printf("nullfs_mount: lower %s, alias at %s\n", 206 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 207#endif 208 return error; 209} 210 211/* 212 * Free reference to null layer 213 */ 214int 215nullfs_unmount(struct mount *mp, int mntflags) 216{ 217 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 218 struct vnode *null_rootvp = nmp->nullm_rootvp; 219 int error; 220 int flags = 0; 221 222#ifdef NULLFS_DIAGNOSTIC 223 printf("nullfs_unmount(mp = %p)\n", mp); 224#endif 225 226 if (mntflags & MNT_FORCE) 227 flags |= FORCECLOSE; 228 229 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 230 return (EBUSY); 231 if ((error = vflush(mp, null_rootvp, flags)) != 0) 232 return (error); 233 234#ifdef NULLFS_DIAGNOSTIC 235 vprint("alias root of lower", null_rootvp); 236#endif 237 /* 238 * Blow it away for future re-use 239 */ 240 vgone(null_rootvp); 241 242 /* 243 * Finally, throw away the null_mount structure 244 */ 245 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash); 246 mutex_destroy(&nmp->nullm_hashlock); 247 free(mp->mnt_data, M_UFSMNT); /* XXX */ 248 mp->mnt_data = NULL; 249 return (0); 250} 251 252SYSCTL_SETUP(sysctl_vfs_null_setup, "sysctl vfs.null subtree setup") 253{ 254 255 sysctl_createv(clog, 0, NULL, NULL, 256 CTLFLAG_PERMANENT, 257 CTLTYPE_NODE, "vfs", NULL, 258 NULL, 0, NULL, 0, 259 CTL_VFS, CTL_EOL); 260 sysctl_createv(clog, 0, NULL, NULL, 261 CTLFLAG_PERMANENT, 262 CTLTYPE_NODE, "null", 263 SYSCTL_DESCR("Loopback file system"), 264 NULL, 0, NULL, 0, 265 CTL_VFS, 9, CTL_EOL); 266 /* 267 * XXX the "9" above could be dynamic, thereby eliminating one 268 * more instance of the "number to vfs" mapping problem, but 269 * "9" is the order as taken from sys/mount.h 270 */ 271} 272 273extern const struct vnodeopv_desc null_vnodeop_opv_desc; 274 275const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 276 &null_vnodeop_opv_desc, 277 NULL, 278}; 279 280struct vfsops nullfs_vfsops = { 281 MOUNT_NULL, 282 sizeof (struct null_args), 283 nullfs_mount, 284 layerfs_start, 285 nullfs_unmount, 286 layerfs_root, 287 layerfs_quotactl, 288 layerfs_statvfs, 289 layerfs_sync, 290 layerfs_vget, 291 layerfs_fhtovp, 292 layerfs_vptofh, 293 layerfs_init, 294 NULL, 295 layerfs_done, 296 NULL, /* vfs_mountroot */ 297 layerfs_snapshot, 298 vfs_stdextattrctl, 299 (void *)eopnotsupp, /* vfs_suspendctl */ 300 layerfs_renamelock_enter, 301 layerfs_renamelock_exit, 302 (void *)eopnotsupp, 303 nullfs_vnodeopv_descs, 304 0, 305 { NULL, NULL }, 306}; 307VFS_ATTACH(nullfs_vfsops); 308