union_vfsops.c revision 1.29
1 /* $NetBSD: union_vfsops.c,v 1.29 2005/08/30 19:11:43 xtraeme 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 1.29 2005/08/30 19:11:43 xtraeme 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(struct mount *, const char *, void *, struct nameidata *, 98 struct proc *); 99 int union_start(struct mount *, int, struct proc *); 100 int union_unmount(struct mount *, int, struct proc *); 101 int union_root(struct mount *, struct vnode **); 102 int union_quotactl(struct mount *, int, uid_t, void *, struct proc *); 103 int union_statvfs(struct mount *, struct statvfs *, struct proc *); 104 int union_sync(struct mount *, int, struct ucred *, struct proc *); 105 int union_vget(struct mount *, ino_t, struct vnode **); 106 int union_fhtovp(struct mount *, struct fid *, struct vnode **); 107 int union_checkexp(struct mount *, struct mbuf *, int *, 108 struct ucred **); 109 int union_vptofh(struct vnode *, struct fid *); 110 111 /* 112 * Mount union filesystem 113 */ 114 int 115 union_mount(mp, path, data, ndp, p) 116 struct mount *mp; 117 const char *path; 118 void *data; 119 struct nameidata *ndp; 120 struct proc *p; 121 { 122 int error = 0; 123 struct union_args args; 124 struct vnode *lowerrootvp = NULLVP; 125 struct vnode *upperrootvp = NULLVP; 126 struct union_mount *um = 0; 127 struct ucred *cred = 0; 128 const char *cp; 129 char *xp; 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, p); 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 = p->p_ucred; 231 crhold(um->um_cred); 232 um->um_cmode = UN_DIRMODE &~ p->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, p); 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 xp = mp->mnt_stat.f_mntfromname + len; 289 len = MNAMELEN - len; 290 291 (void) copyinstr(args.target, xp, len - 1, &size); 292 memset(xp + 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, p) 325 struct mount *mp; 326 int flags; 327 struct proc *p; 328 { 329 330 return (0); 331 } 332 333 /* 334 * Free reference to union layer 335 */ 336 int 337 union_unmount(mp, mntflags, p) 338 struct mount *mp; 339 int mntflags; 340 struct proc *p; 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)) != 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) 423 struct mount *mp; 424 struct vnode **vpp; 425 { 426 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 427 int error; 428 int loselock; 429 430 /* 431 * Return locked reference to root. 432 */ 433 VREF(um->um_uppervp); 434 if ((um->um_op == UNMNT_BELOW) && 435 VOP_ISLOCKED(um->um_uppervp)) { 436 loselock = 1; 437 } else { 438 vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); 439 loselock = 0; 440 } 441 if (um->um_lowervp) 442 VREF(um->um_lowervp); 443 error = union_allocvp(vpp, mp, 444 (struct vnode *) 0, 445 (struct vnode *) 0, 446 (struct componentname *) 0, 447 um->um_uppervp, 448 um->um_lowervp, 449 1); 450 451 if (error) { 452 if (!loselock) 453 VOP_UNLOCK(um->um_uppervp, 0); 454 vrele(um->um_uppervp); 455 if (um->um_lowervp) 456 vrele(um->um_lowervp); 457 } else { 458 if (loselock) 459 VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; 460 } 461 462 return (error); 463 } 464 465 /*ARGSUSED*/ 466 int 467 union_quotactl(mp, cmd, uid, arg, p) 468 struct mount *mp; 469 int cmd; 470 uid_t uid; 471 void *arg; 472 struct proc *p; 473 { 474 475 return (EOPNOTSUPP); 476 } 477 478 int 479 union_statvfs(mp, sbp, p) 480 struct mount *mp; 481 struct statvfs *sbp; 482 struct proc *p; 483 { 484 int error; 485 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 486 struct statvfs *sbuf = malloc(sizeof(*sbuf), M_TEMP, M_WAITOK | M_ZERO); 487 unsigned long lbsize; 488 489 #ifdef UNION_DIAGNOSTIC 490 printf("union_statvfs(mp = %p, lvp = %p, uvp = %p)\n", mp, 491 um->um_lowervp, um->um_uppervp); 492 #endif 493 494 if (um->um_lowervp) { 495 error = VFS_STATVFS(um->um_lowervp->v_mount, sbuf, p); 496 if (error) 497 goto done; 498 } 499 500 /* now copy across the "interesting" information and fake the rest */ 501 lbsize = sbuf->f_bsize; 502 sbp->f_blocks = sbuf->f_blocks - sbuf->f_bfree; 503 sbp->f_files = sbuf->f_files - sbuf->f_ffree; 504 505 error = VFS_STATVFS(um->um_uppervp->v_mount, sbuf, p); 506 if (error) 507 goto done; 508 509 sbp->f_flag = sbuf->f_flag; 510 sbp->f_bsize = sbuf->f_bsize; 511 sbp->f_frsize = sbuf->f_frsize; 512 sbp->f_iosize = sbuf->f_iosize; 513 514 /* 515 * The "total" fields count total resources in all layers, 516 * the "free" fields count only those resources which are 517 * free in the upper layer (since only the upper layer 518 * is writable). 519 */ 520 521 if (sbuf->f_bsize != lbsize) 522 sbp->f_blocks = sbp->f_blocks * lbsize / sbuf->f_bsize; 523 sbp->f_blocks += sbuf->f_blocks; 524 sbp->f_bfree = sbuf->f_bfree; 525 sbp->f_bavail = sbuf->f_bavail; 526 sbp->f_bresvd = sbuf->f_bresvd; 527 sbp->f_files += sbuf->f_files; 528 sbp->f_ffree = sbuf->f_ffree; 529 sbp->f_favail = sbuf->f_favail; 530 sbp->f_fresvd = sbuf->f_fresvd; 531 532 copy_statvfs_info(sbp, mp); 533 done: 534 free(sbuf, M_TEMP); 535 return error; 536 } 537 538 /*ARGSUSED*/ 539 int 540 union_sync(mp, waitfor, cred, p) 541 struct mount *mp; 542 int waitfor; 543 struct ucred *cred; 544 struct proc *p; 545 { 546 547 /* 548 * XXX - Assumes no data cached at union layer. 549 */ 550 return (0); 551 } 552 553 /*ARGSUSED*/ 554 int 555 union_vget(mp, ino, vpp) 556 struct mount *mp; 557 ino_t ino; 558 struct vnode **vpp; 559 { 560 561 return (EOPNOTSUPP); 562 } 563 564 /*ARGSUSED*/ 565 int 566 union_fhtovp(mp, fidp, vpp) 567 struct mount *mp; 568 struct fid *fidp; 569 struct vnode **vpp; 570 { 571 572 return (EOPNOTSUPP); 573 } 574 575 /*ARGSUSED*/ 576 int 577 union_checkexp(mp, nam, exflagsp, credanonp) 578 struct mount *mp; 579 struct mbuf *nam; 580 int *exflagsp; 581 struct ucred **credanonp; 582 { 583 584 return (EOPNOTSUPP); 585 } 586 587 /*ARGSUSED*/ 588 int 589 union_vptofh(vp, fhp) 590 struct vnode *vp; 591 struct fid *fhp; 592 { 593 594 return (EOPNOTSUPP); 595 } 596 597 SYSCTL_SETUP(sysctl_vfs_union_setup, "sysctl vfs.union subtree setup") 598 { 599 600 sysctl_createv(clog, 0, NULL, NULL, 601 CTLFLAG_PERMANENT, 602 CTLTYPE_NODE, "vfs", NULL, 603 NULL, 0, NULL, 0, 604 CTL_VFS, CTL_EOL); 605 sysctl_createv(clog, 0, NULL, NULL, 606 CTLFLAG_PERMANENT, 607 CTLTYPE_NODE, "union", 608 SYSCTL_DESCR("Union file system"), 609 NULL, 0, NULL, 0, 610 CTL_VFS, 15, CTL_EOL); 611 /* 612 * XXX the "15" above could be dynamic, thereby eliminating 613 * one more instance of the "number to vfs" mapping problem, 614 * but "15" is the order as taken from sys/mount.h 615 */ 616 } 617 618 extern const struct vnodeopv_desc union_vnodeop_opv_desc; 619 620 const struct vnodeopv_desc * const union_vnodeopv_descs[] = { 621 &union_vnodeop_opv_desc, 622 NULL, 623 }; 624 625 struct vfsops union_vfsops = { 626 MOUNT_UNION, 627 union_mount, 628 union_start, 629 union_unmount, 630 union_root, 631 union_quotactl, 632 union_statvfs, 633 union_sync, 634 union_vget, 635 union_fhtovp, 636 union_vptofh, 637 union_init, 638 NULL, /* vfs_reinit */ 639 union_done, 640 NULL, 641 NULL, /* vfs_mountroot */ 642 union_checkexp, 643 (int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp, 644 vfs_stdextattrctl, 645 union_vnodeopv_descs, 646 }; 647 VFS_ATTACH(union_vfsops); 648
Indexes created Sun Oct 12 20:09:57 GMT 2025