null_vfsops.c revision 1.54
1/* $NetBSD: null_vfsops.c,v 1.54 2005/02/26 22:59:00 perry 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 1.54 2005/02/26 22:59:00 perry 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 92int nullfs_mount __P((struct mount *, const char *, void *, 93 struct nameidata *, struct proc *)); 94int nullfs_unmount __P((struct mount *, int, struct proc *)); 95 96/* 97 * Mount null layer 98 */ 99int 100nullfs_mount(mp, path, data, ndp, p) 101 struct mount *mp; 102 const char *path; 103 void *data; 104 struct nameidata *ndp; 105 struct proc *p; 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 vfs_showexport(mp, &args.la.export, &lmp->layerm_export); 123 return copyout(&args, data, sizeof(args)); 124 } 125 /* 126 * Get argument 127 */ 128 error = copyin(data, &args, sizeof(struct null_args)); 129 if (error) 130 return (error); 131 132 /* 133 * Update only does export updating. 134 */ 135 if (mp->mnt_flag & MNT_UPDATE) { 136 lmp = MOUNTTOLAYERMOUNT(mp); 137 if (args.nulla_target == NULL) 138 return (vfs_export(mp, &lmp->layerm_export, 139 &args.la.export)); 140 else 141 return (EOPNOTSUPP); 142 } 143 144 /* 145 * Find lower node 146 */ 147 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, 148 UIO_USERSPACE, args.la.target, p); 149 if ((error = namei(ndp)) != 0) 150 return (error); 151 152 /* 153 * Sanity check on lower vnode 154 */ 155 lowerrootvp = ndp->ni_vp; 156 157 /* 158 * First cut at fixing up upper mount point 159 */ 160 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 161 M_UFSMNT, M_WAITOK); /* XXX */ 162 memset(nmp, 0, sizeof(struct null_mount)); 163 164 mp->mnt_data = nmp; 165 mp->mnt_leaf = lowerrootvp->v_mount->mnt_leaf; 166 nmp->nullm_vfs = lowerrootvp->v_mount; 167 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 168 mp->mnt_flag |= MNT_LOCAL; 169 170 /* 171 * Make sure that the mount point is sufficiently initialized 172 * that the node create call will work. 173 */ 174 vfs_getnewfsid(mp); 175 176 nmp->nullm_size = sizeof(struct null_node); 177 nmp->nullm_tag = VT_NULL; 178 nmp->nullm_bypass = layer_bypass; 179 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 180 nmp->nullm_vnodeop_p = null_vnodeop_p; 181 simple_lock_init(&nmp->nullm_hashlock); 182 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, M_CACHE, 183 M_WAITOK, &nmp->nullm_node_hash); 184 185 /* 186 * Fix up null node for root vnode 187 */ 188 error = layer_node_create(mp, lowerrootvp, &vp); 189 /* 190 * Make sure the fixup worked 191 */ 192 if (error) { 193 vput(lowerrootvp); 194 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 195 free(nmp, M_UFSMNT); /* XXX */ 196 return (error); 197 } 198 /* 199 * Unlock the node 200 */ 201 VOP_UNLOCK(vp, 0); 202 203 /* 204 * Keep a held reference to the root vnode. 205 * It is vrele'd in nullfs_unmount. 206 */ 207 vp->v_flag |= VROOT; 208 nmp->nullm_rootvp = vp; 209 210 error = set_statvfs_info(path, UIO_USERSPACE, args.la.target, 211 UIO_USERSPACE, mp, p); 212#ifdef NULLFS_DIAGNOSTIC 213 printf("nullfs_mount: lower %s, alias at %s\n", 214 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 215#endif 216 return error; 217} 218 219/* 220 * Free reference to null layer 221 */ 222int 223nullfs_unmount(mp, mntflags, p) 224 struct mount *mp; 225 int mntflags; 226 struct proc *p; 227{ 228 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 229 struct vnode *null_rootvp = nmp->nullm_rootvp; 230 int error; 231 int flags = 0; 232 233#ifdef NULLFS_DIAGNOSTIC 234 printf("nullfs_unmount(mp = %p)\n", mp); 235#endif 236 237 if (mntflags & MNT_FORCE) 238 flags |= FORCECLOSE; 239 240 /* 241 * Clear out buffer cache. I don't think we 242 * ever get anything cached at this level at the 243 * moment, but who knows... 244 */ 245#if 0 246 mntflushbuf(mp, 0); 247 if (mntinvalbuf(mp, 1)) 248 return (EBUSY); 249#endif 250 if (null_rootvp->v_usecount > 1) 251 return (EBUSY); 252 if ((error = vflush(mp, null_rootvp, flags)) != 0) 253 return (error); 254 255#ifdef NULLFS_DIAGNOSTIC 256 vprint("alias root of lower", null_rootvp); 257#endif 258 /* 259 * Release reference on underlying root vnode 260 */ 261 vrele(null_rootvp); 262 263 /* 264 * And blow it away for future re-use 265 */ 266 vgone(null_rootvp); 267 268 /* 269 * Finally, throw away the null_mount structure 270 */ 271 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 272 free(mp->mnt_data, M_UFSMNT); /* XXX */ 273 mp->mnt_data = NULL; 274 return (0); 275} 276 277SYSCTL_SETUP(sysctl_vfs_null_setup, "sysctl vfs.null subtree setup") 278{ 279 280 sysctl_createv(clog, 0, NULL, NULL, 281 CTLFLAG_PERMANENT, 282 CTLTYPE_NODE, "vfs", NULL, 283 NULL, 0, NULL, 0, 284 CTL_VFS, CTL_EOL); 285 sysctl_createv(clog, 0, NULL, NULL, 286 CTLFLAG_PERMANENT, 287 CTLTYPE_NODE, "null", 288 SYSCTL_DESCR("Loopback file system"), 289 NULL, 0, NULL, 0, 290 CTL_VFS, 9, CTL_EOL); 291 /* 292 * XXX the "9" above could be dynamic, thereby eliminating one 293 * more instance of the "number to vfs" mapping problem, but 294 * "9" is the order as taken from sys/mount.h 295 */ 296} 297 298extern const struct vnodeopv_desc null_vnodeop_opv_desc; 299 300const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 301 &null_vnodeop_opv_desc, 302 NULL, 303}; 304 305struct vfsops nullfs_vfsops = { 306 MOUNT_NULL, 307 nullfs_mount, 308 layerfs_start, 309 nullfs_unmount, 310 layerfs_root, 311 layerfs_quotactl, 312 layerfs_statvfs, 313 layerfs_sync, 314 layerfs_vget, 315 layerfs_fhtovp, 316 layerfs_vptofh, 317 layerfs_init, 318 NULL, 319 layerfs_done, 320 NULL, 321 NULL, /* vfs_mountroot */ 322 layerfs_checkexp, 323 layerfs_snapshot, 324 vfs_stdextattrctl, 325 nullfs_vnodeopv_descs, 326}; 327