null_vfsops.c revision 24987
1/* 2 * Copyright (c) 1992, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software donated to Berkeley by 6 * Jan-Simon Pendry. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94 37 * 38 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 39 * $Id: null_vfsops.c,v 1.14 1997/02/22 09:40:21 peter Exp $ 40 */ 41 42/* 43 * Null Layer 44 * (See null_vnops.c for a description of what this does.) 45 */ 46 47#include <sys/param.h> 48#include <sys/systm.h> 49#include <sys/kernel.h> 50#include <sys/proc.h> 51#include <sys/time.h> 52#include <sys/types.h> 53#include <sys/vnode.h> 54#include <sys/mount.h> 55#include <sys/namei.h> 56#include <sys/malloc.h> 57#include <miscfs/nullfs/null.h> 58 59static int nullfs_fhtovp __P((struct mount *mp, struct fid *fidp, 60 struct mbuf *nam, struct vnode **vpp, 61 int *exflagsp, struct ucred **credanonp)); 62static int nullfs_mount __P((struct mount *mp, char *path, caddr_t data, 63 struct nameidata *ndp, struct proc *p)); 64static int nullfs_quotactl __P((struct mount *mp, int cmd, uid_t uid, 65 caddr_t arg, struct proc *p)); 66static int nullfs_root __P((struct mount *mp, struct vnode **vpp)); 67static int nullfs_start __P((struct mount *mp, int flags, struct proc *p)); 68static int nullfs_statfs __P((struct mount *mp, struct statfs *sbp, 69 struct proc *p)); 70static int nullfs_sync __P((struct mount *mp, int waitfor, 71 struct ucred *cred, struct proc *p)); 72static int nullfs_unmount __P((struct mount *mp, int mntflags, 73 struct proc *p)); 74static int nullfs_vget __P((struct mount *mp, ino_t ino, 75 struct vnode **vpp)); 76static int nullfs_vptofh __P((struct vnode *vp, struct fid *fhp)); 77 78/* 79 * Mount null layer 80 */ 81static int 82nullfs_mount(mp, path, data, ndp, p) 83 struct mount *mp; 84 char *path; 85 caddr_t data; 86 struct nameidata *ndp; 87 struct proc *p; 88{ 89 int error = 0; 90 struct null_args args; 91 struct vnode *lowerrootvp, *vp; 92 struct vnode *nullm_rootvp; 93 struct null_mount *xmp; 94 u_int size; 95 96#ifdef NULLFS_DIAGNOSTIC 97 printf("nullfs_mount(mp = %x)\n", mp); 98#endif 99 100 /* 101 * Update is a no-op 102 */ 103 if (mp->mnt_flag & MNT_UPDATE) { 104 return (EOPNOTSUPP); 105 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 106 } 107 108 /* 109 * Get argument 110 */ 111 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 112 if (error) 113 return (error); 114 115 /* 116 * Find lower node 117 */ 118 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 119 UIO_USERSPACE, args.target, p); 120 error = namei(ndp); 121 if (error) 122 return (error); 123 124 /* 125 * Sanity check on lower vnode 126 */ 127 lowerrootvp = ndp->ni_vp; 128 129 vrele(ndp->ni_dvp); 130 ndp->ni_dvp = NULLVP; 131 132 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 133 M_UFSMNT, M_WAITOK); /* XXX */ 134 135 /* 136 * Save reference to underlying FS 137 */ 138 xmp->nullm_vfs = lowerrootvp->v_mount; 139 140 /* 141 * Save reference. Each mount also holds 142 * a reference on the root vnode. 143 */ 144 error = null_node_create(mp, lowerrootvp, &vp); 145 /* 146 * Unlock the node (either the lower or the alias) 147 */ 148 VOP_UNLOCK(vp, 0, p); 149 /* 150 * Make sure the node alias worked 151 */ 152 if (error) { 153 vrele(lowerrootvp); 154 free(xmp, M_UFSMNT); /* XXX */ 155 return (error); 156 } 157 158 /* 159 * Keep a held reference to the root vnode. 160 * It is vrele'd in nullfs_unmount. 161 */ 162 nullm_rootvp = vp; 163 nullm_rootvp->v_flag |= VROOT; 164 xmp->nullm_rootvp = nullm_rootvp; 165 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 166 mp->mnt_flag |= MNT_LOCAL; 167 mp->mnt_data = (qaddr_t) xmp; 168 vfs_getnewfsid(mp); 169 170 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 171 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 172 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 173 &size); 174 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 175#ifdef NULLFS_DIAGNOSTIC 176 printf("nullfs_mount: lower %s, alias at %s\n", 177 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 178#endif 179 return (0); 180} 181 182/* 183 * VFS start. Nothing needed here - the start routine 184 * on the underlying filesystem will have been called 185 * when that filesystem was mounted. 186 */ 187static int 188nullfs_start(mp, flags, p) 189 struct mount *mp; 190 int flags; 191 struct proc *p; 192{ 193 return (0); 194 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 195} 196 197/* 198 * Free reference to null layer 199 */ 200static int 201nullfs_unmount(mp, mntflags, p) 202 struct mount *mp; 203 int mntflags; 204 struct proc *p; 205{ 206 struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 207 int error; 208 int flags = 0; 209 210#ifdef NULLFS_DIAGNOSTIC 211 printf("nullfs_unmount(mp = %x)\n", mp); 212#endif 213 214 if (mntflags & MNT_FORCE) 215 flags |= FORCECLOSE; 216 217 /* 218 * Clear out buffer cache. I don't think we 219 * ever get anything cached at this level at the 220 * moment, but who knows... 221 */ 222#if 0 223 mntflushbuf(mp, 0); 224 if (mntinvalbuf(mp, 1)) 225 return (EBUSY); 226#endif 227 if (nullm_rootvp->v_usecount > 1) 228 return (EBUSY); 229 error = vflush(mp, nullm_rootvp, flags); 230 if (error) 231 return (error); 232 233#ifdef NULLFS_DIAGNOSTIC 234 vprint("alias root of lower", nullm_rootvp); 235#endif 236 /* 237 * Release reference on underlying root vnode 238 */ 239 vrele(nullm_rootvp); 240 /* 241 * And blow it away for future re-use 242 */ 243 vgone(nullm_rootvp); 244 /* 245 * Finally, throw away the null_mount structure 246 */ 247 free(mp->mnt_data, M_UFSMNT); /* XXX */ 248 mp->mnt_data = 0; 249 return 0; 250} 251 252static int 253nullfs_root(mp, vpp) 254 struct mount *mp; 255 struct vnode **vpp; 256{ 257 struct proc *p = curproc; /* XXX */ 258 struct vnode *vp; 259 260#ifdef NULLFS_DIAGNOSTIC 261 printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp, 262 MOUNTTONULLMOUNT(mp)->nullm_rootvp, 263 NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp) 264 ); 265#endif 266 267 /* 268 * Return locked reference to root. 269 */ 270 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 271 VREF(vp); 272 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 273 *vpp = vp; 274 return 0; 275} 276 277static int 278nullfs_quotactl(mp, cmd, uid, arg, p) 279 struct mount *mp; 280 int cmd; 281 uid_t uid; 282 caddr_t arg; 283 struct proc *p; 284{ 285 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 286} 287 288static int 289nullfs_statfs(mp, sbp, p) 290 struct mount *mp; 291 struct statfs *sbp; 292 struct proc *p; 293{ 294 int error; 295 struct statfs mstat; 296 297#ifdef NULLFS_DIAGNOSTIC 298 printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp, 299 MOUNTTONULLMOUNT(mp)->nullm_rootvp, 300 NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp) 301 ); 302#endif 303 304 bzero(&mstat, sizeof(mstat)); 305 306 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 307 if (error) 308 return (error); 309 310 /* now copy across the "interesting" information and fake the rest */ 311 sbp->f_type = mstat.f_type; 312 sbp->f_flags = mstat.f_flags; 313 sbp->f_bsize = mstat.f_bsize; 314 sbp->f_iosize = mstat.f_iosize; 315 sbp->f_blocks = mstat.f_blocks; 316 sbp->f_bfree = mstat.f_bfree; 317 sbp->f_bavail = mstat.f_bavail; 318 sbp->f_files = mstat.f_files; 319 sbp->f_ffree = mstat.f_ffree; 320 if (sbp != &mp->mnt_stat) { 321 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 322 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 323 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 324 } 325 return (0); 326} 327 328static int 329nullfs_sync(mp, waitfor, cred, p) 330 struct mount *mp; 331 int waitfor; 332 struct ucred *cred; 333 struct proc *p; 334{ 335 /* 336 * XXX - Assumes no data cached at null layer. 337 */ 338 return (0); 339} 340 341static int 342nullfs_vget(mp, ino, vpp) 343 struct mount *mp; 344 ino_t ino; 345 struct vnode **vpp; 346{ 347 348 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 349} 350 351static int 352nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp) 353 struct mount *mp; 354 struct fid *fidp; 355 struct mbuf *nam; 356 struct vnode **vpp; 357 int *exflagsp; 358 struct ucred**credanonp; 359{ 360 361 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp); 362} 363 364static int 365nullfs_vptofh(vp, fhp) 366 struct vnode *vp; 367 struct fid *fhp; 368{ 369 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 370} 371 372static struct vfsops null_vfsops = { 373 nullfs_mount, 374 nullfs_start, 375 nullfs_unmount, 376 nullfs_root, 377 nullfs_quotactl, 378 nullfs_statfs, 379 nullfs_sync, 380 nullfs_vget, 381 nullfs_fhtovp, 382 nullfs_vptofh, 383 nullfs_init, 384}; 385 386VFS_SET(null_vfsops, null, MOUNT_NULL, VFCF_LOOPBACK); 387