bsd/miscfs/nullfs/null_vfsops.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  23 /*
  24  * Copyright (c) 1992, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * This code is derived from software donated to Berkeley by
  28  * Jan-Simon Pendry.
  29  *
  30  * Redistribution and use in source and binary forms, with or without
  31  * modification, are permitted provided that the following conditions
  32  * are met:
  33  * 1. Redistributions of source code must retain the above copyright
  34  *    notice, this list of conditions and the following disclaimer.
  35  * 2. Redistributions in binary form must reproduce the above copyright
  36  *    notice, this list of conditions and the following disclaimer in the
  37  *    documentation and/or other materials provided with the distribution.
  38  * 3. All advertising materials mentioning features or use of this software
  39  *    must display the following acknowledgement:
  40  *      This product includes software developed by the University of
  41  *      California, Berkeley and its contributors.
  42  * 4. Neither the name of the University nor the names of its contributors
  43  *    may be used to endorse or promote products derived from this software
  44  *    without specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  *
  58  *      @(#)null_vfsops.c       8.7 (Berkeley) 5/14/95
  59  *
  60  * @(#)lofs_vfsops.c    1.2 (Berkeley) 6/18/92
  61  */
  62
  63 /*
  64  * Null Layer
  65  * (See null_vnops.c for a description of what this does.)
  66  */
  67
  68 #include <sys/param.h>
  69 #include <sys/systm.h>
  70 #include <sys/proc.h>
  71 #include <sys/time.h>
  72 #include <sys/types.h>
  73 #include <sys/vnode.h>
  74 #include <sys/mount.h>
  75 #include <sys/namei.h>
  76 #include <sys/malloc.h>
  77 #include <miscfs/nullfs/null.h>
  78
  79 /*
  80  * Mount null layer
  81  */
  82 int
  83 nullfs_mount(mp, path, data, ndp, p)
  84         struct mount *mp;
  85         char *path;
  86         caddr_t data;
  87         struct nameidata *ndp;
  88         struct proc *p;
  89 {
  90         int error = 0;
  91         struct null_args args;
  92         struct vnode *lowerrootvp, *vp;
  93         struct vnode *nullm_rootvp;
  94         struct null_mount *xmp;
  95         u_int size;
  96
  97 #ifdef NULLFS_DIAGNOSTIC
  98         printf("nullfs_mount(mp = %x)\n", mp);
  99 #endif
 100
 101         /*
 102          * Update is a no-op
 103          */
 104         if (mp->mnt_flag & MNT_UPDATE) {
 105                 return (EOPNOTSUPP);
 106                 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/
 107         }
 108
 109         /*
 110          * Get argument
 111          */
 112         if (error = copyin(data, (caddr_t)&args, sizeof(struct null_args)))
 113                 return (error);
 114
 115         /*
 116          * Find lower node
 117          */
 118         NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
 119                 UIO_USERSPACE, args.target, p);
 120         if (error = namei(ndp))
 121                 return (error);
 122
 123         /*
 124          * Sanity check on lower vnode
 125          */
 126         lowerrootvp = ndp->ni_vp;
 127
 128         vrele(ndp->ni_dvp);
 129         ndp->ni_dvp = NULL;
 130
 131         xmp = (struct null_mount *) _MALLOC(sizeof(struct null_mount),
 132                                 M_UFSMNT, M_WAITOK);    /* XXX */
 133
 134         /*
 135          * Save reference to underlying FS
 136          */
 137         xmp->nullm_vfs = lowerrootvp->v_mount;
 138
 139         /*
 140          * Save reference.  Each mount also holds
 141          * a reference on the root vnode.
 142          */
 143         error = null_node_create(mp, lowerrootvp, &vp);
 144         /*
 145          * Unlock the node (either the lower or the alias)
 146          */
 147         VOP_UNLOCK(vp, 0, p);
 148         /*
 149          * Make sure the node alias worked
 150          */
 151         if (error) {
 152                 vrele(lowerrootvp);
 153                 FREE(xmp, M_UFSMNT);    /* XXX */
 154                 return (error);
 155         }
 156
 157         /*
 158          * Keep a held reference to the root vnode.
 159          * It is vrele'd in nullfs_unmount.
 160          */
 161         nullm_rootvp = vp;
 162         nullm_rootvp->v_flag |= VROOT;
 163         xmp->nullm_rootvp = nullm_rootvp;
 164         if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
 165                 mp->mnt_flag |= MNT_LOCAL;
 166         mp->mnt_data = (qaddr_t) xmp;
 167         vfs_getnewfsid(mp);
 168
 169         (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
 170         bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
 171         (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
 172             &size);
 173         bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
 174 #ifdef NULLFS_DIAGNOSTIC
 175         printf("nullfs_mount: lower %s, alias at %s\n",
 176                 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
 177 #endif
 178         return (0);
 179 }
 180
 181 /*
 182  * VFS start.  Nothing needed here - the start routine
 183  * on the underlying filesystem will have been called
 184  * when that filesystem was mounted.
 185  */
 186 int
 187 nullfs_start(mp, flags, p)
 188         struct mount *mp;
 189         int flags;
 190         struct proc *p;
 191 {
 192         return (0);
 193         /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */
 194 }
 195
 196 /*
 197  * Free reference to null layer
 198  */
 199 int
 200 nullfs_unmount(mp, mntflags, p)
 201         struct mount *mp;
 202         int mntflags;
 203         struct proc *p;
 204 {
 205         struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
 206         int error;
 207         int flags = 0;
 208
 209 #ifdef NULLFS_DIAGNOSTIC
 210         printf("nullfs_unmount(mp = %x)\n", mp);
 211 #endif
 212
 213         if (mntflags & MNT_FORCE)
 214                 flags |= FORCECLOSE;
 215
 216         /*
 217          * Clear out buffer cache.  I don't think we
 218          * ever get anything cached at this level at the
 219          * moment, but who knows...
 220          */
 221 #if 0
 222         mntflushbuf(mp, 0);
 223         if (mntinvalbuf(mp, 1))
 224                 return (EBUSY);
 225 #endif
 226         if (nullm_rootvp->v_usecount > 1)
 227                 return (EBUSY);
 228         if (error = vflush(mp, nullm_rootvp, flags))
 229                 return (error);
 230
 231 #ifdef NULLFS_DIAGNOSTIC
 232         vprint("alias root of lower", nullm_rootvp);
 233 #endif
 234         /*
 235          * Release reference on underlying root vnode
 236          */
 237         vrele(nullm_rootvp);
 238         /*
 239          * And blow it away for future re-use
 240          */
 241         vgone(nullm_rootvp);
 242         /*
 243          * Finally, throw away the null_mount structure
 244          */
 245         FREE(mp->mnt_data, M_UFSMNT);   /* XXX */
 246         mp->mnt_data = 0;
 247         return 0;
 248 }
 249
 250 int
 251 nullfs_root(mp, vpp)
 252         struct mount *mp;
 253         struct vnode **vpp;
 254 {
 255         struct proc *p = curproc;       /* XXX */
 256         struct vnode *vp;
 257
 258 #ifdef NULLFS_DIAGNOSTIC
 259         printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp,
 260                         MOUNTTONULLMOUNT(mp)->nullm_rootvp,
 261                         NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
 262                         );
 263 #endif
 264
 265         /*
 266          * Return locked reference to root.
 267          */
 268         vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
 269         VREF(vp);
 270         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
 271         *vpp = vp;
 272         return 0;
 273 }
 274
 275 int
 276 nullfs_quotactl(mp, cmd, uid, arg, p)
 277         struct mount *mp;
 278         int cmd;
 279         uid_t uid;
 280         caddr_t arg;
 281         struct proc *p;
 282 {
 283         return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p);
 284 }
 285
 286 int
 287 nullfs_statfs(mp, sbp, p)
 288         struct mount *mp;
 289         struct statfs *sbp;
 290         struct proc *p;
 291 {
 292         int error;
 293         struct statfs mstat;
 294
 295 #ifdef NULLFS_DIAGNOSTIC
 296         printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp,
 297                         MOUNTTONULLMOUNT(mp)->nullm_rootvp,
 298                         NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
 299                         );
 300 #endif
 301
 302         bzero(&mstat, sizeof(mstat));
 303
 304         error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p);
 305         if (error)
 306                 return (error);
 307
 308         /* now copy across the "interesting" information and fake the rest */
 309         sbp->f_type = mstat.f_type;
 310         sbp->f_flags = mstat.f_flags;
 311         sbp->f_bsize = mstat.f_bsize;
 312         sbp->f_iosize = mstat.f_iosize;
 313         sbp->f_blocks = mstat.f_blocks;
 314         sbp->f_bfree = mstat.f_bfree;
 315         sbp->f_bavail = mstat.f_bavail;
 316         sbp->f_files = mstat.f_files;
 317         sbp->f_ffree = mstat.f_ffree;
 318         if (sbp != &mp->mnt_stat) {
 319                 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
 320                 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
 321                 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
 322         }
 323         return (0);
 324 }
 325
 326 int
 327 nullfs_sync(mp, waitfor, cred, p)
 328         struct mount *mp;
 329         int waitfor;
 330         struct ucred *cred;
 331         struct proc *p;
 332 {
 333         /*
 334          * XXX - Assumes no data cached at null layer.
 335          */
 336         return (0);
 337 }
 338
 339 int
 340 nullfs_vget(mp, ino, vpp)
 341         struct mount *mp;
 342         ino_t ino;
 343         struct vnode **vpp;
 344 {
 345
 346         return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
 347 }
 348
 349 int
 350 nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
 351         struct mount *mp;
 352         struct fid *fidp;
 353         struct mbuf *nam;
 354         struct vnode **vpp;
 355         int *exflagsp;
 356         struct ucred**credanonp;
 357 {
 358
 359         return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp);
 360 }
 361
 362 int
 363 nullfs_vptofh(vp, fhp)
 364         struct vnode *vp;
 365         struct fid *fhp;
 366 {
 367         return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
 368 }
 369
 370 int nullfs_init __P((struct vfsconf *));
 371
 372 #define nullfs_sysctl ((int (*) __P((int *, u_int, void *, size_t *, void *, \
 373             size_t, struct proc *)))eopnotsupp)
 374
 375 struct vfsops null_vfsops = {
 376         nullfs_mount,
 377         nullfs_start,
 378         nullfs_unmount,
 379         nullfs_root,
 380         nullfs_quotactl,
 381         nullfs_statfs,
 382         nullfs_sync,
 383         nullfs_vget,
 384         nullfs_fhtovp,
 385         nullfs_vptofh,
 386         nullfs_init,
 387         nullfs_sysctl,
 388 };