union_vfsops.c revision 1.7
1 /* $NetBSD: union_vfsops.c,v 1.7 2003/06/29 18:43:27 thorpej Exp $ */ 2 3 /* 4 * Copyright (c) 1994 The Regents of the University of California. 5 * Copyright (c) 1994 Jan-Simon Pendry. 6 * All rights reserved. 7 * 8 * This code is derived from software donated to Berkeley by 9 * Jan-Simon Pendry. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95 40 */ 41 42 /* 43 * Union Layer 44 */ 45 46 #include <sys/cdefs.h> 47 __KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.7 2003/06/29 18:43:27 thorpej Exp $"); 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/time.h> 52 #include <sys/proc.h> 53 #include <sys/vnode.h> 54 #include <sys/mount.h> 55 #include <sys/namei.h> 56 #include <sys/malloc.h> 57 #include <sys/filedesc.h> 58 #include <sys/queue.h> 59 #include <sys/stat.h> 60 61 #include <fs/union/union.h> 62 63 int union_mount __P((struct mount *, const char *, void *, struct nameidata *, 64 struct lwp *)); 65 int union_start __P((struct mount *, int, struct lwp *)); 66 int union_unmount __P((struct mount *, int, struct lwp *)); 67 int union_root __P((struct mount *, struct vnode **)); 68 int union_quotactl __P((struct mount *, int, uid_t, caddr_t, struct lwp *)); 69 int union_statfs __P((struct mount *, struct statfs *, struct lwp *)); 70 int union_sync __P((struct mount *, int, struct ucred *, struct lwp *)); 71 int union_vget __P((struct mount *, ino_t, struct vnode **)); 72 int union_fhtovp __P((struct mount *, struct fid *, struct vnode **)); 73 int union_checkexp __P((struct mount *, struct mbuf *, int *, 74 struct ucred **)); 75 int union_vptofh __P((struct vnode *, struct fid *)); 76 int union_sysctl __P((int *, u_int, void *, size_t *, void *, size_t, 77 struct lwp *)); 78 79 /* 80 * Mount union filesystem 81 */ 82 int 83 union_mount(mp, path, data, ndp, l) 84 struct mount *mp; 85 const char *path; 86 void *data; 87 struct nameidata *ndp; 88 struct lwp *l; 89 { 90 int error = 0; 91 struct union_args args; 92 struct proc *p = l->l_proc; 93 struct vnode *lowerrootvp = NULLVP; 94 struct vnode *upperrootvp = NULLVP; 95 struct union_mount *um = 0; 96 struct ucred *cred = 0; 97 char *cp; 98 int len; 99 size_t size; 100 101 #ifdef UNION_DIAGNOSTIC 102 printf("union_mount(mp = %p)\n", mp); 103 #endif 104 105 if (mp->mnt_flag & MNT_GETARGS) { 106 um = MOUNTTOUNIONMOUNT(mp); 107 if (um == NULL) 108 return EIO; 109 args.target = NULL; 110 args.mntflags = um->um_op; 111 return copyout(&args, data, sizeof(args)); 112 } 113 /* 114 * Update is a no-op 115 */ 116 if (mp->mnt_flag & MNT_UPDATE) { 117 /* 118 * Need to provide. 119 * 1. a way to convert between rdonly and rdwr mounts. 120 * 2. support for nfs exports. 121 */ 122 error = EOPNOTSUPP; 123 goto bad; 124 } 125 126 /* 127 * Get argument 128 */ 129 error = copyin(data, (caddr_t)&args, sizeof(struct union_args)); 130 if (error) 131 goto bad; 132 133 lowerrootvp = mp->mnt_vnodecovered; 134 VREF(lowerrootvp); 135 136 /* 137 * Find upper node. 138 */ 139 NDINIT(ndp, LOOKUP, FOLLOW, 140 UIO_USERSPACE, args.target, l); 141 142 if ((error = namei(ndp)) != 0) 143 goto bad; 144 145 upperrootvp = ndp->ni_vp; 146 147 if (upperrootvp->v_type != VDIR) { 148 error = EINVAL; 149 goto bad; 150 } 151 152 um = (struct union_mount *) malloc(sizeof(struct union_mount), 153 M_UFSMNT, M_WAITOK); /* XXX */ 154 155 /* 156 * Keep a held reference to the target vnodes. 157 * They are vrele'd in union_unmount. 158 * 159 * Depending on the _BELOW flag, the filesystems are 160 * viewed in a different order. In effect, this is the 161 * same as providing a mount under option to the mount syscall. 162 */ 163 164 um->um_op = args.mntflags & UNMNT_OPMASK; 165 switch (um->um_op) { 166 case UNMNT_ABOVE: 167 um->um_lowervp = lowerrootvp; 168 um->um_uppervp = upperrootvp; 169 break; 170 171 case UNMNT_BELOW: 172 um->um_lowervp = upperrootvp; 173 um->um_uppervp = lowerrootvp; 174 break; 175 176 case UNMNT_REPLACE: 177 vrele(lowerrootvp); 178 lowerrootvp = NULLVP; 179 um->um_uppervp = upperrootvp; 180 um->um_lowervp = lowerrootvp; 181 break; 182 183 default: 184 error = EINVAL; 185 goto bad; 186 } 187 188 /* 189 * Unless the mount is readonly, ensure that the top layer 190 * supports whiteout operations 191 */ 192 if ((mp->mnt_flag & MNT_RDONLY) == 0) { 193 error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP); 194 if (error) 195 goto bad; 196 } 197 198 um->um_cred = p->p_ucred; 199 crhold(um->um_cred); 200 um->um_cmode = UN_DIRMODE &~ p->p_cwdi->cwdi_cmask; 201 202 /* 203 * Depending on what you think the MNT_LOCAL flag might mean, 204 * you may want the && to be || on the conditional below. 205 * At the moment it has been defined that the filesystem is 206 * only local if it is all local, ie the MNT_LOCAL flag implies 207 * that the entire namespace is local. If you think the MNT_LOCAL 208 * flag implies that some of the files might be stored locally 209 * then you will want to change the conditional. 210 */ 211 if (um->um_op == UNMNT_ABOVE) { 212 if (((um->um_lowervp == NULLVP) || 213 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) && 214 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL)) 215 mp->mnt_flag |= MNT_LOCAL; 216 } 217 218 /* 219 * Copy in the upper layer's RDONLY flag. This is for the benefit 220 * of lookup() which explicitly checks the flag, rather than asking 221 * the filesystem for it's own opinion. This means, that an update 222 * mount of the underlying filesystem to go from rdonly to rdwr 223 * will leave the unioned view as read-only. 224 */ 225 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY); 226 227 mp->mnt_data = um; 228 vfs_getnewfsid(mp); 229 230 error = set_statfs_info( path, UIO_USERSPACE, NULL, UIO_USERSPACE, 231 mp, l); 232 if (error) 233 goto bad; 234 235 switch (um->um_op) { 236 case UNMNT_ABOVE: 237 cp = "<above>:"; 238 break; 239 case UNMNT_BELOW: 240 cp = "<below>:"; 241 break; 242 case UNMNT_REPLACE: 243 cp = ""; 244 break; 245 default: 246 cp = "<invalid>:"; 247 #ifdef DIAGNOSTIC 248 panic("union_mount: bad um_op"); 249 #endif 250 break; 251 } 252 len = strlen(cp); 253 memcpy(mp->mnt_stat.f_mntfromname, cp, len); 254 255 cp = mp->mnt_stat.f_mntfromname + len; 256 len = MNAMELEN - len; 257 258 (void) copyinstr(args.target, cp, len - 1, &size); 259 memset(cp + size, 0, len - size); 260 261 #ifdef UNION_DIAGNOSTIC 262 printf("union_mount: from %s, on %s\n", 263 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 264 #endif 265 266 /* Setup the readdir hook if it's not set already */ 267 if (!vn_union_readdir_hook) 268 vn_union_readdir_hook = union_readdirhook; 269 270 return (0); 271 272 bad: 273 if (um) 274 free(um, M_UFSMNT); 275 if (cred) 276 crfree(cred); 277 if (upperrootvp) 278 vrele(upperrootvp); 279 if (lowerrootvp) 280 vrele(lowerrootvp); 281 return (error); 282 } 283 284 /* 285 * VFS start. Nothing needed here - the start routine 286 * on the underlying filesystem(s) will have been called 287 * when that filesystem was mounted. 288 */ 289 /*ARGSUSED*/ 290 int 291 union_start(mp, flags, l) 292 struct mount *mp; 293 int flags; 294 struct lwp *l; 295 { 296 297 return (0); 298 } 299 300 /* 301 * Free reference to union layer 302 */ 303 int 304 union_unmount(mp, mntflags, l) 305 struct mount *mp; 306 int mntflags; 307 struct lwp *l; 308 { 309 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 310 struct vnode *um_rootvp; 311 int error; 312 int freeing; 313 314 #ifdef UNION_DIAGNOSTIC 315 printf("union_unmount(mp = %p)\n", mp); 316 #endif 317 318 if ((error = union_root(mp, &um_rootvp)) != 0) 319 return (error); 320 321 /* 322 * Keep flushing vnodes from the mount list. 323 * This is needed because of the un_pvp held 324 * reference to the parent vnode. 325 * If more vnodes have been freed on a given pass, 326 * the try again. The loop will iterate at most 327 * (d) times, where (d) is the maximum tree depth 328 * in the filesystem. 329 */ 330 for (freeing = 0; vflush(mp, um_rootvp, 0) != 0;) { 331 struct vnode *vp; 332 int n; 333 334 /* count #vnodes held on mount list */ 335 for (n = 0, vp = mp->mnt_vnodelist.lh_first; 336 vp != NULLVP; 337 vp = vp->v_mntvnodes.le_next) 338 n++; 339 340 /* if this is unchanged then stop */ 341 if (n == freeing) 342 break; 343 344 /* otherwise try once more time */ 345 freeing = n; 346 } 347 348 /* 349 * Ok, now that we've tried doing it gently, get out the hammer. 350 */ 351 352 if (mntflags & MNT_FORCE) 353 vflush(mp, um_rootvp, FORCECLOSE); 354 355 356 /* At this point the root vnode should have a single reference */ 357 if (um_rootvp->v_usecount > 1) { 358 vput(um_rootvp); 359 return (EBUSY); 360 } 361 362 #ifdef UNION_DIAGNOSTIC 363 vprint("union root", um_rootvp); 364 #endif 365 /* 366 * Discard references to upper and lower target vnodes. 367 */ 368 if (um->um_lowervp) 369 vrele(um->um_lowervp); 370 vrele(um->um_uppervp); 371 crfree(um->um_cred); 372 /* 373 * Release reference on underlying root vnode 374 */ 375 vput(um_rootvp); 376 /* 377 * And blow it away for future re-use 378 */ 379 vgone(um_rootvp); 380 /* 381 * Finally, throw away the union_mount structure 382 */ 383 free(mp->mnt_data, M_UFSMNT); /* XXX */ 384 mp->mnt_data = 0; 385 return (0); 386 } 387 388 int 389 union_root(mp, vpp) 390 struct mount *mp; 391 struct vnode **vpp; 392 { 393 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 394 int error; 395 int loselock; 396 397 /* 398 * Return locked reference to root. 399 */ 400 VREF(um->um_uppervp); 401 if ((um->um_op == UNMNT_BELOW) && 402 VOP_ISLOCKED(um->um_uppervp)) { 403 loselock = 1; 404 } else { 405 vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); 406 loselock = 0; 407 } 408 if (um->um_lowervp) 409 VREF(um->um_lowervp); 410 error = union_allocvp(vpp, mp, 411 (struct vnode *) 0, 412 (struct vnode *) 0, 413 (struct componentname *) 0, 414 um->um_uppervp, 415 um->um_lowervp, 416 1); 417 418 if (error) { 419 if (!loselock) 420 VOP_UNLOCK(um->um_uppervp, 0); 421 vrele(um->um_uppervp); 422 if (um->um_lowervp) 423 vrele(um->um_lowervp); 424 } else { 425 if (loselock) 426 VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; 427 } 428 429 return (error); 430 } 431 432 /*ARGSUSED*/ 433 int 434 union_quotactl(mp, cmd, uid, arg, l) 435 struct mount *mp; 436 int cmd; 437 uid_t uid; 438 caddr_t arg; 439 struct lwp *l; 440 { 441 442 return (EOPNOTSUPP); 443 } 444 445 int 446 union_statfs(mp, sbp, l) 447 struct mount *mp; 448 struct statfs *sbp; 449 struct lwp *l; 450 { 451 int error; 452 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 453 struct statfs mstat; 454 int lbsize; 455 456 #ifdef UNION_DIAGNOSTIC 457 printf("union_statfs(mp = %p, lvp = %p, uvp = %p)\n", mp, 458 um->um_lowervp, um->um_uppervp); 459 #endif 460 461 memset(&mstat, 0, sizeof(mstat)); 462 463 if (um->um_lowervp) { 464 error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, l); 465 if (error) 466 return (error); 467 } 468 469 /* now copy across the "interesting" information and fake the rest */ 470 lbsize = mstat.f_bsize; 471 sbp->f_blocks = mstat.f_blocks - mstat.f_bfree; 472 sbp->f_files = mstat.f_files - mstat.f_ffree; 473 474 error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, l); 475 if (error) 476 return (error); 477 478 sbp->f_type = 0; 479 sbp->f_flags = mstat.f_flags; 480 sbp->f_bsize = mstat.f_bsize; 481 sbp->f_iosize = mstat.f_iosize; 482 483 /* 484 * The "total" fields count total resources in all layers, 485 * the "free" fields count only those resources which are 486 * free in the upper layer (since only the upper layer 487 * is writable). 488 */ 489 490 if (mstat.f_bsize != lbsize) 491 sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize; 492 sbp->f_blocks += mstat.f_blocks; 493 sbp->f_bfree = mstat.f_bfree; 494 sbp->f_bavail = mstat.f_bavail; 495 sbp->f_files += mstat.f_files; 496 sbp->f_ffree = mstat.f_ffree; 497 498 copy_statfs_info(sbp, mp); 499 return (0); 500 } 501 502 /*ARGSUSED*/ 503 int 504 union_sync(mp, waitfor, cred, l) 505 struct mount *mp; 506 int waitfor; 507 struct ucred *cred; 508 struct lwp *l; 509 { 510 511 /* 512 * XXX - Assumes no data cached at union layer. 513 */ 514 return (0); 515 } 516 517 /*ARGSUSED*/ 518 int 519 union_vget(mp, ino, vpp) 520 struct mount *mp; 521 ino_t ino; 522 struct vnode **vpp; 523 { 524 525 return (EOPNOTSUPP); 526 } 527 528 /*ARGSUSED*/ 529 int 530 union_fhtovp(mp, fidp, vpp) 531 struct mount *mp; 532 struct fid *fidp; 533 struct vnode **vpp; 534 { 535 536 return (EOPNOTSUPP); 537 } 538 539 /*ARGSUSED*/ 540 int 541 union_checkexp(mp, nam, exflagsp, credanonp) 542 struct mount *mp; 543 struct mbuf *nam; 544 int *exflagsp; 545 struct ucred **credanonp; 546 { 547 548 return (EOPNOTSUPP); 549 } 550 551 /*ARGSUSED*/ 552 int 553 union_vptofh(vp, fhp) 554 struct vnode *vp; 555 struct fid *fhp; 556 { 557 558 return (EOPNOTSUPP); 559 } 560 561 int 562 union_sysctl(name, namelen, oldp, oldlenp, newp, newlen, l) 563 int *name; 564 u_int namelen; 565 void *oldp; 566 size_t *oldlenp; 567 void *newp; 568 size_t newlen; 569 struct lwp *l; 570 { 571 return (EOPNOTSUPP); 572 } 573 574 extern const struct vnodeopv_desc union_vnodeop_opv_desc; 575 576 const struct vnodeopv_desc * const union_vnodeopv_descs[] = { 577 &union_vnodeop_opv_desc, 578 NULL, 579 }; 580 581 struct vfsops union_vfsops = { 582 MOUNT_UNION, 583 union_mount, 584 union_start, 585 union_unmount, 586 union_root, 587 union_quotactl, 588 union_statfs, 589 union_sync, 590 union_vget, 591 union_fhtovp, 592 union_vptofh, 593 union_init, 594 NULL, /* vfs_reinit */ 595 union_done, 596 union_sysctl, 597 NULL, /* vfs_mountroot */ 598 union_checkexp, 599 union_vnodeopv_descs, 600 }; 601
Indexes created Mon Oct 13 08:09:50 GMT 2025