null_vfsops.c revision 22521
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 * $FreeBSD: head/sys/fs/nullfs/null_vfsops.c 22521 1997-02-10 02:22:35Z dyson $ 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/proc.h> 50#include <sys/time.h> 51#include <sys/types.h> 52#include <sys/vnode.h> 53#include <sys/mount.h> 54#include <sys/namei.h> 55#include <sys/malloc.h> 56#include <miscfs/nullfs/null.h> 57 58extern int nullfs_init __P((struct vfsconf *)); 59 60static int nullfs_fhtovp __P((struct mount *mp, struct fid *fidp, 61 struct mbuf *nam, struct vnode **vpp, 62 int *exflagsp, struct ucred **credanonp)); 63static int nullfs_mount __P((struct mount *mp, char *path, caddr_t data, 64 struct nameidata *ndp, struct proc *p)); 65static int nullfs_quotactl __P((struct mount *mp, int cmd, uid_t uid, 66 caddr_t arg, struct proc *p)); 67static int nullfs_root __P((struct mount *mp, struct vnode **vpp)); 68static int nullfs_start __P((struct mount *mp, int flags, struct proc *p)); 69static int nullfs_statfs __P((struct mount *mp, struct statfs *sbp, 70 struct proc *p)); 71static int nullfs_sync __P((struct mount *mp, int waitfor, 72 struct ucred *cred, struct proc *p)); 73static int nullfs_unmount __P((struct mount *mp, int mntflags, 74 struct proc *p)); 75static int nullfs_vget __P((struct mount *mp, ino_t ino, 76 struct vnode **vpp)); 77static int nullfs_vptofh __P((struct vnode *vp, struct fid *fhp)); 78 79/* 80 * Mount null layer 81 */ 82static int 83nullfs_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 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 113 if (error) 114 return (error); 115 116 /* 117 * Find lower node 118 */ 119 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 120 UIO_USERSPACE, args.target, p); 121 error = namei(ndp); 122 if (error) 123 return (error); 124 125 /* 126 * Sanity check on lower vnode 127 */ 128 lowerrootvp = ndp->ni_vp; 129 130 vrele(ndp->ni_dvp); 131 ndp->ni_dvp = NULL; 132 133 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 134 M_UFSMNT, M_WAITOK); /* XXX */ 135 136 /* 137 * Save reference to underlying FS 138 */ 139 xmp->nullm_vfs = lowerrootvp->v_mount; 140 141 /* 142 * Save reference. Each mount also holds 143 * a reference on the root vnode. 144 */ 145 error = null_node_create(mp, lowerrootvp, &vp); 146 /* 147 * Unlock the node (either the lower or the alias) 148 */ 149 VOP_UNLOCK(vp, 0, p); 150 /* 151 * Make sure the node alias worked 152 */ 153 if (error) { 154 vrele(lowerrootvp); 155 free(xmp, M_UFSMNT); /* XXX */ 156 return (error); 157 } 158 159 /* 160 * Keep a held reference to the root vnode. 161 * It is vrele'd in nullfs_unmount. 162 */ 163 nullm_rootvp = vp; 164 nullm_rootvp->v_flag |= VROOT; 165 xmp->nullm_rootvp = nullm_rootvp; 166 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 167 mp->mnt_flag |= MNT_LOCAL; 168 mp->mnt_data = (qaddr_t) xmp; 169 vfs_getnewfsid(mp); 170 171 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 172 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 173 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 174 &size); 175 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 176#ifdef NULLFS_DIAGNOSTIC 177 printf("nullfs_mount: lower %s, alias at %s\n", 178 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 179#endif 180 return (0); 181} 182 183/* 184 * VFS start. Nothing needed here - the start routine 185 * on the underlying filesystem will have been called 186 * when that filesystem was mounted. 187 */ 188static int 189nullfs_start(mp, flags, p) 190 struct mount *mp; 191 int flags; 192 struct proc *p; 193{ 194 return (0); 195 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 196} 197 198/* 199 * Free reference to null layer 200 */ 201static int 202nullfs_unmount(mp, mntflags, p) 203 struct mount *mp; 204 int mntflags; 205 struct proc *p; 206{ 207 struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 208 int error; 209 int flags = 0; 210 211#ifdef NULLFS_DIAGNOSTIC 212 printf("nullfs_unmount(mp = %x)\n", mp); 213#endif 214 215 if (mntflags & MNT_FORCE) 216 flags |= FORCECLOSE; 217 218 /* 219 * Clear out buffer cache. I don't think we 220 * ever get anything cached at this level at the 221 * moment, but who knows... 222 */ 223#if 0 224 mntflushbuf(mp, 0); 225 if (mntinvalbuf(mp, 1)) 226 return (EBUSY); 227#endif 228 if (nullm_rootvp->v_usecount > 1) 229 return (EBUSY); 230 error = vflush(mp, nullm_rootvp, flags); 231 if (error) 232 return (error); 233 234#ifdef NULLFS_DIAGNOSTIC 235 vprint("alias root of lower", nullm_rootvp); 236#endif 237 /* 238 * Release reference on underlying root vnode 239 */ 240 vrele(nullm_rootvp); 241 /* 242 * And blow it away for future re-use 243 */ 244 vgone(nullm_rootvp); 245 /* 246 * Finally, throw away the null_mount structure 247 */ 248 free(mp->mnt_data, M_UFSMNT); /* XXX */ 249 mp->mnt_data = 0; 250 return 0; 251} 252 253static int 254nullfs_root(mp, vpp) 255 struct mount *mp; 256 struct vnode **vpp; 257{ 258 struct proc *p = curproc; /* XXX */ 259 struct vnode *vp; 260 261#ifdef NULLFS_DIAGNOSTIC 262 printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp, 263 MOUNTTONULLMOUNT(mp)->nullm_rootvp, 264 NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp) 265 ); 266#endif 267 268 /* 269 * Return locked reference to root. 270 */ 271 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 272 VREF(vp); 273 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 274 *vpp = vp; 275 return 0; 276} 277 278static int 279nullfs_quotactl(mp, cmd, uid, arg, p) 280 struct mount *mp; 281 int cmd; 282 uid_t uid; 283 caddr_t arg; 284 struct proc *p; 285{ 286 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 287} 288 289static int 290nullfs_statfs(mp, sbp, p) 291 struct mount *mp; 292 struct statfs *sbp; 293 struct proc *p; 294{ 295 int error; 296 struct statfs mstat; 297 298#ifdef NULLFS_DIAGNOSTIC 299 printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp, 300 MOUNTTONULLMOUNT(mp)->nullm_rootvp, 301 NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp) 302 ); 303#endif 304 305 bzero(&mstat, sizeof(mstat)); 306 307 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 308 if (error) 309 return (error); 310 311 /* now copy across the "interesting" information and fake the rest */ 312 sbp->f_type = mstat.f_type; 313 sbp->f_flags = mstat.f_flags; 314 sbp->f_bsize = mstat.f_bsize; 315 sbp->f_iosize = mstat.f_iosize; 316 sbp->f_blocks = mstat.f_blocks; 317 sbp->f_bfree = mstat.f_bfree; 318 sbp->f_bavail = mstat.f_bavail; 319 sbp->f_files = mstat.f_files; 320 sbp->f_ffree = mstat.f_ffree; 321 if (sbp != &mp->mnt_stat) { 322 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 323 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 324 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 325 } 326 return (0); 327} 328 329static int 330nullfs_sync(mp, waitfor, cred, p) 331 struct mount *mp; 332 int waitfor; 333 struct ucred *cred; 334 struct proc *p; 335{ 336 /* 337 * XXX - Assumes no data cached at null layer. 338 */ 339 return (0); 340} 341 342static int 343nullfs_vget(mp, ino, vpp) 344 struct mount *mp; 345 ino_t ino; 346 struct vnode **vpp; 347{ 348 349 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 350} 351 352static int 353nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp) 354 struct mount *mp; 355 struct fid *fidp; 356 struct mbuf *nam; 357 struct vnode **vpp; 358 int *exflagsp; 359 struct ucred**credanonp; 360{ 361 362 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp); 363} 364 365static int 366nullfs_vptofh(vp, fhp) 367 struct vnode *vp; 368 struct fid *fhp; 369{ 370 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 371} 372 373static struct vfsops null_vfsops = { 374 nullfs_mount, 375 nullfs_start, 376 nullfs_unmount, 377 nullfs_root, 378 nullfs_quotactl, 379 nullfs_statfs, 380 nullfs_sync, 381 nullfs_vget, 382 nullfs_fhtovp, 383 nullfs_vptofh, 384 nullfs_init, 385}; 386 387VFS_SET(null_vfsops, null, MOUNT_NULL, VFCF_LOOPBACK); 388