null_vfsops.c revision 22597
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 22597 1997-02-12 14:55:01Z mpp $ 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 58static int nullfs_fhtovp __P((struct mount *mp, struct fid *fidp, 59 struct mbuf *nam, struct vnode **vpp, 60 int *exflagsp, struct ucred **credanonp)); 61static int nullfs_mount __P((struct mount *mp, char *path, caddr_t data, 62 struct nameidata *ndp, struct proc *p)); 63static int nullfs_quotactl __P((struct mount *mp, int cmd, uid_t uid, 64 caddr_t arg, struct proc *p)); 65static int nullfs_root __P((struct mount *mp, struct vnode **vpp)); 66static int nullfs_start __P((struct mount *mp, int flags, struct proc *p)); 67static int nullfs_statfs __P((struct mount *mp, struct statfs *sbp, 68 struct proc *p)); 69static int nullfs_sync __P((struct mount *mp, int waitfor, 70 struct ucred *cred, struct proc *p)); 71static int nullfs_unmount __P((struct mount *mp, int mntflags, 72 struct proc *p)); 73static int nullfs_vget __P((struct mount *mp, ino_t ino, 74 struct vnode **vpp)); 75static int nullfs_vptofh __P((struct vnode *vp, struct fid *fhp)); 76 77/* 78 * Mount null layer 79 */ 80static int 81nullfs_mount(mp, path, data, ndp, p) 82 struct mount *mp; 83 char *path; 84 caddr_t data; 85 struct nameidata *ndp; 86 struct proc *p; 87{ 88 int error = 0; 89 struct null_args args; 90 struct vnode *lowerrootvp, *vp; 91 struct vnode *nullm_rootvp; 92 struct null_mount *xmp; 93 u_int size; 94 95#ifdef NULLFS_DIAGNOSTIC 96 printf("nullfs_mount(mp = %x)\n", mp); 97#endif 98 99 /* 100 * Update is a no-op 101 */ 102 if (mp->mnt_flag & MNT_UPDATE) { 103 return (EOPNOTSUPP); 104 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 105 } 106 107 /* 108 * Get argument 109 */ 110 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 111 if (error) 112 return (error); 113 114 /* 115 * Find lower node 116 */ 117 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 118 UIO_USERSPACE, args.target, p); 119 error = namei(ndp); 120 if (error) 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 */ 186static int 187nullfs_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 */ 199static int 200nullfs_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 error = vflush(mp, nullm_rootvp, flags); 229 if (error) 230 return (error); 231 232#ifdef NULLFS_DIAGNOSTIC 233 vprint("alias root of lower", nullm_rootvp); 234#endif 235 /* 236 * Release reference on underlying root vnode 237 */ 238 vrele(nullm_rootvp); 239 /* 240 * And blow it away for future re-use 241 */ 242 vgone(nullm_rootvp); 243 /* 244 * Finally, throw away the null_mount structure 245 */ 246 free(mp->mnt_data, M_UFSMNT); /* XXX */ 247 mp->mnt_data = 0; 248 return 0; 249} 250 251static int 252nullfs_root(mp, vpp) 253 struct mount *mp; 254 struct vnode **vpp; 255{ 256 struct proc *p = curproc; /* XXX */ 257 struct vnode *vp; 258 259#ifdef NULLFS_DIAGNOSTIC 260 printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp, 261 MOUNTTONULLMOUNT(mp)->nullm_rootvp, 262 NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp) 263 ); 264#endif 265 266 /* 267 * Return locked reference to root. 268 */ 269 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 270 VREF(vp); 271 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 272 *vpp = vp; 273 return 0; 274} 275 276static int 277nullfs_quotactl(mp, cmd, uid, arg, p) 278 struct mount *mp; 279 int cmd; 280 uid_t uid; 281 caddr_t arg; 282 struct proc *p; 283{ 284 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 285} 286 287static int 288nullfs_statfs(mp, sbp, p) 289 struct mount *mp; 290 struct statfs *sbp; 291 struct proc *p; 292{ 293 int error; 294 struct statfs mstat; 295 296#ifdef NULLFS_DIAGNOSTIC 297 printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp, 298 MOUNTTONULLMOUNT(mp)->nullm_rootvp, 299 NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp) 300 ); 301#endif 302 303 bzero(&mstat, sizeof(mstat)); 304 305 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 306 if (error) 307 return (error); 308 309 /* now copy across the "interesting" information and fake the rest */ 310 sbp->f_type = mstat.f_type; 311 sbp->f_flags = mstat.f_flags; 312 sbp->f_bsize = mstat.f_bsize; 313 sbp->f_iosize = mstat.f_iosize; 314 sbp->f_blocks = mstat.f_blocks; 315 sbp->f_bfree = mstat.f_bfree; 316 sbp->f_bavail = mstat.f_bavail; 317 sbp->f_files = mstat.f_files; 318 sbp->f_ffree = mstat.f_ffree; 319 if (sbp != &mp->mnt_stat) { 320 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 321 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 322 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 323 } 324 return (0); 325} 326 327static int 328nullfs_sync(mp, waitfor, cred, p) 329 struct mount *mp; 330 int waitfor; 331 struct ucred *cred; 332 struct proc *p; 333{ 334 /* 335 * XXX - Assumes no data cached at null layer. 336 */ 337 return (0); 338} 339 340static int 341nullfs_vget(mp, ino, vpp) 342 struct mount *mp; 343 ino_t ino; 344 struct vnode **vpp; 345{ 346 347 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 348} 349 350static int 351nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp) 352 struct mount *mp; 353 struct fid *fidp; 354 struct mbuf *nam; 355 struct vnode **vpp; 356 int *exflagsp; 357 struct ucred**credanonp; 358{ 359 360 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp); 361} 362 363static int 364nullfs_vptofh(vp, fhp) 365 struct vnode *vp; 366 struct fid *fhp; 367{ 368 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 369} 370 371static struct vfsops null_vfsops = { 372 nullfs_mount, 373 nullfs_start, 374 nullfs_unmount, 375 nullfs_root, 376 nullfs_quotactl, 377 nullfs_statfs, 378 nullfs_sync, 379 nullfs_vget, 380 nullfs_fhtovp, 381 nullfs_vptofh, 382 nullfs_init, 383}; 384 385VFS_SET(null_vfsops, null, MOUNT_NULL, VFCF_LOOPBACK); 386