null_vfsops.c revision 78179
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 78179 2001-06-13 18:58:11Z mjacob $ 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/lock.h> 51#include <sys/malloc.h> 52#include <sys/mount.h> 53#include <sys/namei.h> 54#include <sys/proc.h> 55#include <sys/vnode.h> 56 57#include <fs/nullfs/null.h> 58 59static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 60 61static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 62 struct vnode **vpp); 63static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 64 int *extflagsp, struct ucred **credanonp); 65static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 66 struct nameidata *ndp, struct proc *p); 67static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 68 caddr_t arg, struct proc *p); 69static int nullfs_root(struct mount *mp, struct vnode **vpp); 70static int nullfs_start(struct mount *mp, int flags, struct proc *p); 71static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 72 struct proc *p); 73static int nullfs_sync(struct mount *mp, int waitfor, 74 struct ucred *cred, struct proc *p); 75static int nullfs_unmount(struct mount *mp, int mntflags, struct proc *p); 76static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 77static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 78static int nullfs_extattrctl(struct mount *mp, int cmd, 79 struct vnode *filename_vp, 80 int namespace, const char *attrname, 81 struct proc *p); 82 83/* 84 * Mount null layer 85 */ 86static int 87nullfs_mount(mp, path, data, ndp, p) 88 struct mount *mp; 89 char *path; 90 caddr_t data; 91 struct nameidata *ndp; 92 struct proc *p; 93{ 94 int error = 0; 95 struct null_args args; 96 struct vnode *lowerrootvp, *vp; 97 struct vnode *nullm_rootvp; 98 struct null_mount *xmp; 99 size_t size; 100 int isvnunlocked = 0; 101 102 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 103 104 /* 105 * Update is a no-op 106 */ 107 if (mp->mnt_flag & MNT_UPDATE) { 108 return (EOPNOTSUPP); 109 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 110 } 111 112 /* 113 * Get argument 114 */ 115 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 116 if (error) 117 return (error); 118 119 /* 120 * Unlock lower node to avoid deadlock. 121 * (XXX) VOP_ISLOCKED is needed? 122 */ 123 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 124 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 125 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p); 126 isvnunlocked = 1; 127 } 128 /* 129 * Find lower node 130 */ 131 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 132 UIO_USERSPACE, args.target, p); 133 error = namei(ndp); 134 /* 135 * Re-lock vnode. 136 */ 137 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 138 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 139 140 if (error) 141 return (error); 142 NDFREE(ndp, NDF_ONLY_PNBUF); 143 144 /* 145 * Sanity check on lower vnode 146 */ 147 lowerrootvp = ndp->ni_vp; 148 149 vrele(ndp->ni_dvp); 150 ndp->ni_dvp = NULLVP; 151 152 /* 153 * Check multi null mount to avoid `lock against myself' panic. 154 */ 155 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 156 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 157 vput(lowerrootvp); 158 return (EDEADLK); 159 } 160 161 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 162 M_NULLFSMNT, M_WAITOK); /* XXX */ 163 164 /* 165 * Save reference to underlying FS 166 */ 167 xmp->nullm_vfs = lowerrootvp->v_mount; 168 169 /* 170 * Save reference. Each mount also holds 171 * a reference on the root vnode. 172 */ 173 error = null_node_create(mp, lowerrootvp, &vp); 174 /* 175 * Unlock the node (either the lower or the alias) 176 */ 177 VOP_UNLOCK(vp, 0, p); 178 /* 179 * Make sure the node alias worked 180 */ 181 if (error) { 182 vrele(lowerrootvp); 183 free(xmp, M_NULLFSMNT); /* XXX */ 184 return (error); 185 } 186 187 /* 188 * Keep a held reference to the root vnode. 189 * It is vrele'd in nullfs_unmount. 190 */ 191 nullm_rootvp = vp; 192 nullm_rootvp->v_flag |= VROOT; 193 xmp->nullm_rootvp = nullm_rootvp; 194 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 195 mp->mnt_flag |= MNT_LOCAL; 196 mp->mnt_data = (qaddr_t) xmp; 197 vfs_getnewfsid(mp); 198 199 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, 200 MNAMELEN - 1, &size); 201 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 202 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 203 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 204 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 205 return (0); 206} 207 208/* 209 * VFS start. Nothing needed here - the start routine 210 * on the underlying filesystem will have been called 211 * when that filesystem was mounted. 212 */ 213static int 214nullfs_start(mp, flags, p) 215 struct mount *mp; 216 int flags; 217 struct proc *p; 218{ 219 return (0); 220 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 221} 222 223/* 224 * Free reference to null layer 225 */ 226static int 227nullfs_unmount(mp, mntflags, p) 228 struct mount *mp; 229 int mntflags; 230 struct proc *p; 231{ 232 void *mntdata; 233 int error; 234 int flags = 0; 235 236 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 237 238 if (mntflags & MNT_FORCE) 239 flags |= FORCECLOSE; 240 241 /* There is 1 extra root vnode reference (nullm_rootvp). */ 242 error = vflush(mp, 1, flags); 243 if (error) 244 return (error); 245 246 /* 247 * Finally, throw away the null_mount structure 248 */ 249 mntdata = mp->mnt_data; 250 mp->mnt_data = 0; 251 free(mntdata, M_NULLFSMNT); 252 return 0; 253} 254 255static int 256nullfs_root(mp, vpp) 257 struct mount *mp; 258 struct vnode **vpp; 259{ 260 struct proc *p = curproc; /* XXX */ 261 struct vnode *vp; 262 263 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 264 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 265 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 266 267 /* 268 * Return locked reference to root. 269 */ 270 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 271 VREF(vp); 272 273#ifdef NULLFS_DEBUG 274 if (VOP_ISLOCKED(vp, NULL)) { 275 Debugger("root vnode is locked.\n"); 276 vrele(vp); 277 return (EDEADLK); 278 } 279#endif 280 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 281 *vpp = vp; 282 return 0; 283} 284 285static int 286nullfs_quotactl(mp, cmd, uid, arg, p) 287 struct mount *mp; 288 int cmd; 289 uid_t uid; 290 caddr_t arg; 291 struct proc *p; 292{ 293 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 294} 295 296static int 297nullfs_statfs(mp, sbp, p) 298 struct mount *mp; 299 struct statfs *sbp; 300 struct proc *p; 301{ 302 int error; 303 struct statfs mstat; 304 305 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 306 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 307 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 308 309 bzero(&mstat, sizeof(mstat)); 310 311 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 312 if (error) 313 return (error); 314 315 /* now copy across the "interesting" information and fake the rest */ 316 sbp->f_type = mstat.f_type; 317 sbp->f_flags = mstat.f_flags; 318 sbp->f_bsize = mstat.f_bsize; 319 sbp->f_iosize = mstat.f_iosize; 320 sbp->f_blocks = mstat.f_blocks; 321 sbp->f_bfree = mstat.f_bfree; 322 sbp->f_bavail = mstat.f_bavail; 323 sbp->f_files = mstat.f_files; 324 sbp->f_ffree = mstat.f_ffree; 325 if (sbp != &mp->mnt_stat) { 326 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 327 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 328 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 329 } 330 return (0); 331} 332 333static int 334nullfs_sync(mp, waitfor, cred, p) 335 struct mount *mp; 336 int waitfor; 337 struct ucred *cred; 338 struct proc *p; 339{ 340 /* 341 * XXX - Assumes no data cached at null layer. 342 */ 343 return (0); 344} 345 346static int 347nullfs_vget(mp, ino, vpp) 348 struct mount *mp; 349 ino_t ino; 350 struct vnode **vpp; 351{ 352 int error; 353 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 354 if (error) 355 return (error); 356 357 return (null_node_create(mp, *vpp, vpp)); 358} 359 360static int 361nullfs_fhtovp(mp, fidp, vpp) 362 struct mount *mp; 363 struct fid *fidp; 364 struct vnode **vpp; 365{ 366 int error; 367 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 368 if (error) 369 return (error); 370 371 return (null_node_create(mp, *vpp, vpp)); 372} 373 374static int 375nullfs_checkexp(mp, nam, extflagsp, credanonp) 376 struct mount *mp; 377 struct sockaddr *nam; 378 int *extflagsp; 379 struct ucred **credanonp; 380{ 381 382 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 383 extflagsp, credanonp); 384} 385 386static int 387nullfs_vptofh(vp, fhp) 388 struct vnode *vp; 389 struct fid *fhp; 390{ 391 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 392} 393 394static int 395nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, p) 396 struct mount *mp; 397 int cmd; 398 struct vnode *filename_vp; 399 int namespace; 400 const char *attrname; 401 struct proc *p; 402{ 403 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 404 namespace, attrname, p); 405} 406 407 408static struct vfsops null_vfsops = { 409 nullfs_mount, 410 nullfs_start, 411 nullfs_unmount, 412 nullfs_root, 413 nullfs_quotactl, 414 nullfs_statfs, 415 nullfs_sync, 416 nullfs_vget, 417 nullfs_fhtovp, 418 nullfs_checkexp, 419 nullfs_vptofh, 420 nullfs_init, 421 nullfs_uninit, 422 nullfs_extattrctl, 423}; 424 425VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 426