union_vfsops.c revision 1.8.2.2
1 /* $NetBSD: union_vfsops.c,v 1.8.2.2 2004/08/03 10:52:42 skrll Exp $ */ 2 3 /* 4 * Copyright (c) 1994 The Regents of the University of California. 5 * All rights reserved. 6 * 7 * This code is derived from software donated to Berkeley by 8 * Jan-Simon Pendry. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95 35 */ 36 37 /* 38 * Copyright (c) 1994 Jan-Simon Pendry. 39 * All rights reserved. 40 * 41 * This code is derived from software donated to Berkeley by 42 * Jan-Simon Pendry. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. All advertising materials mentioning features or use of this software 53 * must display the following acknowledgement: 54 * This product includes software developed by the University of 55 * California, Berkeley and its contributors. 56 * 4. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95 73 */ 74 75 /* 76 * Union Layer 77 */ 78 79 #include <sys/cdefs.h> 80 __KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.8.2.2 2004/08/03 10:52:42 skrll Exp $"); 81 82 #include <sys/param.h> 83 #include <sys/systm.h> 84 #include <sys/sysctl.h> 85 #include <sys/time.h> 86 #include <sys/proc.h> 87 #include <sys/vnode.h> 88 #include <sys/mount.h> 89 #include <sys/namei.h> 90 #include <sys/malloc.h> 91 #include <sys/filedesc.h> 92 #include <sys/queue.h> 93 #include <sys/stat.h> 94 95 #include <fs/union/union.h> 96 97 int union_mount __P((struct mount *, const char *, void *, struct nameidata *, 98 struct lwp *)); 99 int union_start __P((struct mount *, int, struct lwp *)); 100 int union_unmount __P((struct mount *, int, struct lwp *)); 101 int union_root __P((struct mount *, struct vnode **, struct lwp *)); 102 int union_quotactl __P((struct mount *, int, uid_t, void *, struct lwp *)); 103 int union_statvfs __P((struct mount *, struct statvfs *, struct lwp *)); 104 int union_sync __P((struct mount *, int, struct ucred *, struct lwp *)); 105 int union_vget __P((struct mount *, ino_t, struct vnode **, struct lwp *)); 106 int union_fhtovp __P((struct mount *, struct fid *, struct vnode **, 107 struct lwp *)); 108 int union_checkexp __P((struct mount *, struct mbuf *, int *, 109 struct ucred **)); 110 int union_vptofh __P((struct vnode *, struct fid *)); 111 112 /* 113 * Mount union filesystem 114 */ 115 int 116 union_mount(mp, path, data, ndp, l) 117 struct mount *mp; 118 const char *path; 119 void *data; 120 struct nameidata *ndp; 121 struct lwp *l; 122 { 123 int error = 0; 124 struct union_args args; 125 struct vnode *lowerrootvp = NULLVP; 126 struct vnode *upperrootvp = NULLVP; 127 struct union_mount *um = 0; 128 struct ucred *cred = 0; 129 char *cp; 130 int len; 131 size_t size; 132 133 #ifdef UNION_DIAGNOSTIC 134 printf("union_mount(mp = %p)\n", mp); 135 #endif 136 137 if (mp->mnt_flag & MNT_GETARGS) { 138 um = MOUNTTOUNIONMOUNT(mp); 139 if (um == NULL) 140 return EIO; 141 args.target = NULL; 142 args.mntflags = um->um_op; 143 return copyout(&args, data, sizeof(args)); 144 } 145 /* 146 * Update is a no-op 147 */ 148 if (mp->mnt_flag & MNT_UPDATE) { 149 /* 150 * Need to provide. 151 * 1. a way to convert between rdonly and rdwr mounts. 152 * 2. support for nfs exports. 153 */ 154 error = EOPNOTSUPP; 155 goto bad; 156 } 157 158 /* 159 * Get argument 160 */ 161 error = copyin(data, &args, sizeof(struct union_args)); 162 if (error) 163 goto bad; 164 165 lowerrootvp = mp->mnt_vnodecovered; 166 VREF(lowerrootvp); 167 168 /* 169 * Find upper node. 170 */ 171 NDINIT(ndp, LOOKUP, FOLLOW, 172 UIO_USERSPACE, args.target, l); 173 174 if ((error = namei(ndp)) != 0) 175 goto bad; 176 177 upperrootvp = ndp->ni_vp; 178 179 if (upperrootvp->v_type != VDIR) { 180 error = EINVAL; 181 goto bad; 182 } 183 184 um = (struct union_mount *) malloc(sizeof(struct union_mount), 185 M_UFSMNT, M_WAITOK); /* XXX */ 186 187 /* 188 * Keep a held reference to the target vnodes. 189 * They are vrele'd in union_unmount. 190 * 191 * Depending on the _BELOW flag, the filesystems are 192 * viewed in a different order. In effect, this is the 193 * same as providing a mount under option to the mount syscall. 194 */ 195 196 um->um_op = args.mntflags & UNMNT_OPMASK; 197 switch (um->um_op) { 198 case UNMNT_ABOVE: 199 um->um_lowervp = lowerrootvp; 200 um->um_uppervp = upperrootvp; 201 break; 202 203 case UNMNT_BELOW: 204 um->um_lowervp = upperrootvp; 205 um->um_uppervp = lowerrootvp; 206 break; 207 208 case UNMNT_REPLACE: 209 vrele(lowerrootvp); 210 lowerrootvp = NULLVP; 211 um->um_uppervp = upperrootvp; 212 um->um_lowervp = lowerrootvp; 213 break; 214 215 default: 216 error = EINVAL; 217 goto bad; 218 } 219 220 /* 221 * Unless the mount is readonly, ensure that the top layer 222 * supports whiteout operations 223 */ 224 if ((mp->mnt_flag & MNT_RDONLY) == 0) { 225 error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP); 226 if (error) 227 goto bad; 228 } 229 230 um->um_cred = l->l_proc->p_ucred; 231 crhold(um->um_cred); 232 um->um_cmode = UN_DIRMODE &~ l->l_proc->p_cwdi->cwdi_cmask; 233 234 /* 235 * Depending on what you think the MNT_LOCAL flag might mean, 236 * you may want the && to be || on the conditional below. 237 * At the moment it has been defined that the filesystem is 238 * only local if it is all local, ie the MNT_LOCAL flag implies 239 * that the entire namespace is local. If you think the MNT_LOCAL 240 * flag implies that some of the files might be stored locally 241 * then you will want to change the conditional. 242 */ 243 if (um->um_op == UNMNT_ABOVE) { 244 if (((um->um_lowervp == NULLVP) || 245 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) && 246 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL)) 247 mp->mnt_flag |= MNT_LOCAL; 248 } 249 250 /* 251 * Copy in the upper layer's RDONLY flag. This is for the benefit 252 * of lookup() which explicitly checks the flag, rather than asking 253 * the filesystem for it's own opinion. This means, that an update 254 * mount of the underlying filesystem to go from rdonly to rdwr 255 * will leave the unioned view as read-only. 256 */ 257 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY); 258 259 mp->mnt_data = um; 260 mp->mnt_leaf = um->um_uppervp->v_mount->mnt_leaf; 261 vfs_getnewfsid(mp); 262 263 error = set_statvfs_info( path, UIO_USERSPACE, NULL, UIO_USERSPACE, 264 mp, l); 265 if (error) 266 goto bad; 267 268 switch (um->um_op) { 269 case UNMNT_ABOVE: 270 cp = "<above>:"; 271 break; 272 case UNMNT_BELOW: 273 cp = "<below>:"; 274 break; 275 case UNMNT_REPLACE: 276 cp = ""; 277 break; 278 default: 279 cp = "<invalid>:"; 280 #ifdef DIAGNOSTIC 281 panic("union_mount: bad um_op"); 282 #endif 283 break; 284 } 285 len = strlen(cp); 286 memcpy(mp->mnt_stat.f_mntfromname, cp, len); 287 288 cp = mp->mnt_stat.f_mntfromname + len; 289 len = MNAMELEN - len; 290 291 (void) copyinstr(args.target, cp, len - 1, &size); 292 memset(cp + size, 0, len - size); 293 294 #ifdef UNION_DIAGNOSTIC 295 printf("union_mount: from %s, on %s\n", 296 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 297 #endif 298 299 /* Setup the readdir hook if it's not set already */ 300 if (!vn_union_readdir_hook) 301 vn_union_readdir_hook = union_readdirhook; 302 303 return (0); 304 305 bad: 306 if (um) 307 free(um, M_UFSMNT); 308 if (cred) 309 crfree(cred); 310 if (upperrootvp) 311 vrele(upperrootvp); 312 if (lowerrootvp) 313 vrele(lowerrootvp); 314 return (error); 315 } 316 317 /* 318 * VFS start. Nothing needed here - the start routine 319 * on the underlying filesystem(s) will have been called 320 * when that filesystem was mounted. 321 */ 322 /*ARGSUSED*/ 323 int 324 union_start(mp, flags, l) 325 struct mount *mp; 326 int flags; 327 struct lwp *l; 328 { 329 330 return (0); 331 } 332 333 /* 334 * Free reference to union layer 335 */ 336 int 337 union_unmount(mp, mntflags, l) 338 struct mount *mp; 339 int mntflags; 340 struct lwp *l; 341 { 342 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 343 struct vnode *um_rootvp; 344 int error; 345 int freeing; 346 347 #ifdef UNION_DIAGNOSTIC 348 printf("union_unmount(mp = %p)\n", mp); 349 #endif 350 351 if ((error = union_root(mp, &um_rootvp, l)) != 0) 352 return (error); 353 354 /* 355 * Keep flushing vnodes from the mount list. 356 * This is needed because of the un_pvp held 357 * reference to the parent vnode. 358 * If more vnodes have been freed on a given pass, 359 * the try again. The loop will iterate at most 360 * (d) times, where (d) is the maximum tree depth 361 * in the filesystem. 362 */ 363 for (freeing = 0; vflush(mp, um_rootvp, 0) != 0;) { 364 struct vnode *vp; 365 int n; 366 367 /* count #vnodes held on mount list */ 368 for (n = 0, vp = mp->mnt_vnodelist.lh_first; 369 vp != NULLVP; 370 vp = vp->v_mntvnodes.le_next) 371 n++; 372 373 /* if this is unchanged then stop */ 374 if (n == freeing) 375 break; 376 377 /* otherwise try once more time */ 378 freeing = n; 379 } 380 381 /* 382 * Ok, now that we've tried doing it gently, get out the hammer. 383 */ 384 385 if (mntflags & MNT_FORCE) 386 vflush(mp, um_rootvp, FORCECLOSE); 387 388 389 /* At this point the root vnode should have a single reference */ 390 if (um_rootvp->v_usecount > 1) { 391 vput(um_rootvp); 392 return (EBUSY); 393 } 394 395 #ifdef UNION_DIAGNOSTIC 396 vprint("union root", um_rootvp); 397 #endif 398 /* 399 * Discard references to upper and lower target vnodes. 400 */ 401 if (um->um_lowervp) 402 vrele(um->um_lowervp); 403 vrele(um->um_uppervp); 404 crfree(um->um_cred); 405 /* 406 * Release reference on underlying root vnode 407 */ 408 vput(um_rootvp); 409 /* 410 * And blow it away for future re-use 411 */ 412 vgone(um_rootvp); 413 /* 414 * Finally, throw away the union_mount structure 415 */ 416 free(mp->mnt_data, M_UFSMNT); /* XXX */ 417 mp->mnt_data = 0; 418 return (0); 419 } 420 421 int 422 union_root(mp, vpp, l) 423 struct mount *mp; 424 struct vnode **vpp; 425 struct lwp *l; 426 { 427 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 428 int error; 429 int loselock; 430 431 /* 432 * Return locked reference to root. 433 */ 434 VREF(um->um_uppervp); 435 if ((um->um_op == UNMNT_BELOW) && 436 VOP_ISLOCKED(um->um_uppervp)) { 437 loselock = 1; 438 } else { 439 vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); 440 loselock = 0; 441 } 442 if (um->um_lowervp) 443 VREF(um->um_lowervp); 444 error = union_allocvp(vpp, mp, 445 (struct vnode *) 0, 446 (struct vnode *) 0, 447 (struct componentname *) 0, 448 um->um_uppervp, 449 um->um_lowervp, 450 1, 451 l); 452 453 if (error) { 454 if (!loselock) 455 VOP_UNLOCK(um->um_uppervp, 0); 456 vrele(um->um_uppervp); 457 if (um->um_lowervp) 458 vrele(um->um_lowervp); 459 } else { 460 if (loselock) 461 VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; 462 } 463 464 return (error); 465 } 466 467 /*ARGSUSED*/ 468 int 469 union_quotactl(mp, cmd, uid, arg, l) 470 struct mount *mp; 471 int cmd; 472 uid_t uid; 473 void *arg; 474 struct lwp *l; 475 { 476 477 return (EOPNOTSUPP); 478 } 479 480 int 481 union_statvfs(mp, sbp, l) 482 struct mount *mp; 483 struct statvfs *sbp; 484 struct lwp *l; 485 { 486 int error; 487 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 488 struct statvfs *sbuf = malloc(sizeof(*sbuf), M_TEMP, M_WAITOK); 489 unsigned long lbsize; 490 491 #ifdef UNION_DIAGNOSTIC 492 printf("union_statvfs(mp = %p, lvp = %p, uvp = %p)\n", mp, 493 um->um_lowervp, um->um_uppervp); 494 #endif 495 496 if (um->um_lowervp) { 497 error = VFS_STATVFS(um->um_lowervp->v_mount, sbuf, l); 498 if (error) 499 goto done; 500 } 501 502 /* now copy across the "interesting" information and fake the rest */ 503 lbsize = sbuf->f_bsize; 504 sbp->f_blocks = sbuf->f_blocks - sbuf->f_bfree; 505 sbp->f_files = sbuf->f_files - sbuf->f_ffree; 506 507 error = VFS_STATVFS(um->um_uppervp->v_mount, sbuf, l); 508 if (error) 509 goto done; 510 511 sbp->f_flag = sbuf->f_flag; 512 sbp->f_bsize = sbuf->f_bsize; 513 sbp->f_frsize = sbuf->f_frsize; 514 sbp->f_iosize = sbuf->f_iosize; 515 516 /* 517 * The "total" fields count total resources in all layers, 518 * the "free" fields count only those resources which are 519 * free in the upper layer (since only the upper layer 520 * is writable). 521 */ 522 523 if (sbuf->f_bsize != lbsize) 524 sbp->f_blocks = sbp->f_blocks * lbsize / sbuf->f_bsize; 525 sbp->f_blocks += sbuf->f_blocks; 526 sbp->f_bfree = sbuf->f_bfree; 527 sbp->f_bavail = sbuf->f_bavail; 528 sbp->f_bresvd = sbuf->f_bresvd; 529 sbp->f_files += sbuf->f_files; 530 sbp->f_ffree = sbuf->f_ffree; 531 sbp->f_favail = sbuf->f_favail; 532 sbp->f_fresvd = sbuf->f_fresvd; 533 534 copy_statvfs_info(sbp, mp); 535 done: 536 free(sbuf, M_TEMP); 537 return error; 538 } 539 540 /*ARGSUSED*/ 541 int 542 union_sync(mp, waitfor, cred, l) 543 struct mount *mp; 544 int waitfor; 545 struct ucred *cred; 546 struct lwp *l; 547 { 548 549 /* 550 * XXX - Assumes no data cached at union layer. 551 */ 552 return (0); 553 } 554 555 /*ARGSUSED*/ 556 int 557 union_vget(mp, ino, vpp, l) 558 struct mount *mp; 559 ino_t ino; 560 struct vnode **vpp; 561 struct lwp *l; 562 { 563 564 return (EOPNOTSUPP); 565 } 566 567 /*ARGSUSED*/ 568 int 569 union_fhtovp(mp, fidp, vpp, l) 570 struct mount *mp; 571 struct fid *fidp; 572 struct vnode **vpp; 573 struct lwp *l; 574 { 575 576 return (EOPNOTSUPP); 577 } 578 579 /*ARGSUSED*/ 580 int 581 union_checkexp(mp, nam, exflagsp, credanonp) 582 struct mount *mp; 583 struct mbuf *nam; 584 int *exflagsp; 585 struct ucred **credanonp; 586 { 587 588 return (EOPNOTSUPP); 589 } 590 591 /*ARGSUSED*/ 592 int 593 union_vptofh(vp, fhp) 594 struct vnode *vp; 595 struct fid *fhp; 596 { 597 598 return (EOPNOTSUPP); 599 } 600 601 SYSCTL_SETUP(sysctl_vfs_union_setup, "sysctl vfs.union subtree setup") 602 { 603 604 sysctl_createv(clog, 0, NULL, NULL, 605 CTLFLAG_PERMANENT, 606 CTLTYPE_NODE, "vfs", NULL, 607 NULL, 0, NULL, 0, 608 CTL_VFS, CTL_EOL); 609 sysctl_createv(clog, 0, NULL, NULL, 610 CTLFLAG_PERMANENT, 611 CTLTYPE_NODE, "union", 612 SYSCTL_DESCR("Union file system"), 613 NULL, 0, NULL, 0, 614 CTL_VFS, 15, CTL_EOL); 615 /* 616 * XXX the "15" above could be dynamic, thereby eliminating 617 * one more instance of the "number to vfs" mapping problem, 618 * but "15" is the order as taken from sys/mount.h 619 */ 620 } 621 622 extern const struct vnodeopv_desc union_vnodeop_opv_desc; 623 624 const struct vnodeopv_desc * const union_vnodeopv_descs[] = { 625 &union_vnodeop_opv_desc, 626 NULL, 627 }; 628 629 struct vfsops union_vfsops = { 630 MOUNT_UNION, 631 union_mount, 632 union_start, 633 union_unmount, 634 union_root, 635 union_quotactl, 636 union_statvfs, 637 union_sync, 638 union_vget, 639 union_fhtovp, 640 union_vptofh, 641 union_init, 642 NULL, /* vfs_reinit */ 643 union_done, 644 NULL, 645 NULL, /* vfs_mountroot */ 646 union_checkexp, 647 (int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp, 648 union_vnodeopv_descs, 649 }; 650
Indexes created Mon Oct 13 01:09:56 GMT 2025