union_vfsops.c revision 1.21
1 /* $NetBSD: union_vfsops.c,v 1.21 2004/05/30 09:48:37 tron 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 1.21 2004/05/30 09:48:37 tron 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 #include <miscfs/genfs/layer_extern.h> 97 98 int union_mount __P((struct mount *, const char *, void *, struct nameidata *, 99 struct proc *)); 100 int union_start __P((struct mount *, int, struct proc *)); 101 int union_unmount __P((struct mount *, int, struct proc *)); 102 int union_root __P((struct mount *, struct vnode **)); 103 int union_quotactl __P((struct mount *, int, uid_t, void *, struct proc *)); 104 int union_statvfs __P((struct mount *, struct statvfs *, struct proc *)); 105 int union_sync __P((struct mount *, int, struct ucred *, struct proc *)); 106 int union_vget __P((struct mount *, ino_t, struct vnode **)); 107 int union_fhtovp __P((struct mount *, struct fid *, struct vnode **)); 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, p) 117 struct mount *mp; 118 const char *path; 119 void *data; 120 struct nameidata *ndp; 121 struct proc *p; 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, 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 vfs_getnewfsid(mp); 261 262 error = set_statvfs_info( path, UIO_USERSPACE, NULL, UIO_USERSPACE, 263 mp, p); 264 if (error) 265 goto bad; 266 267 switch (um->um_op) { 268 case UNMNT_ABOVE: 269 cp = "<above>:"; 270 break; 271 case UNMNT_BELOW: 272 cp = "<below>:"; 273 break; 274 case UNMNT_REPLACE: 275 cp = ""; 276 break; 277 default: 278 cp = "<invalid>:"; 279 #ifdef DIAGNOSTIC 280 panic("union_mount: bad um_op"); 281 #endif 282 break; 283 } 284 len = strlen(cp); 285 memcpy(mp->mnt_stat.f_mntfromname, cp, len); 286 287 cp = mp->mnt_stat.f_mntfromname + len; 288 len = MNAMELEN - len; 289 290 (void) copyinstr(args.target, cp, len - 1, &size); 291 memset(cp + size, 0, len - size); 292 293 #ifdef UNION_DIAGNOSTIC 294 printf("union_mount: from %s, on %s\n", 295 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 296 #endif 297 298 /* Setup the readdir hook if it's not set already */ 299 if (!vn_union_readdir_hook) 300 vn_union_readdir_hook = union_readdirhook; 301 302 return (0); 303 304 bad: 305 if (um) 306 free(um, M_UFSMNT); 307 if (cred) 308 crfree(cred); 309 if (upperrootvp) 310 vrele(upperrootvp); 311 if (lowerrootvp) 312 vrele(lowerrootvp); 313 return (error); 314 } 315 316 /* 317 * VFS start. Nothing needed here - the start routine 318 * on the underlying filesystem(s) will have been called 319 * when that filesystem was mounted. 320 */ 321 /*ARGSUSED*/ 322 int 323 union_start(mp, flags, p) 324 struct mount *mp; 325 int flags; 326 struct proc *p; 327 { 328 329 return (0); 330 } 331 332 /* 333 * Free reference to union layer 334 */ 335 int 336 union_unmount(mp, mntflags, p) 337 struct mount *mp; 338 int mntflags; 339 struct proc *p; 340 { 341 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 342 struct vnode *um_rootvp; 343 int error; 344 int freeing; 345 346 #ifdef UNION_DIAGNOSTIC 347 printf("union_unmount(mp = %p)\n", mp); 348 #endif 349 350 if ((error = union_root(mp, &um_rootvp)) != 0) 351 return (error); 352 353 /* 354 * Keep flushing vnodes from the mount list. 355 * This is needed because of the un_pvp held 356 * reference to the parent vnode. 357 * If more vnodes have been freed on a given pass, 358 * the try again. The loop will iterate at most 359 * (d) times, where (d) is the maximum tree depth 360 * in the filesystem. 361 */ 362 for (freeing = 0; vflush(mp, um_rootvp, 0) != 0;) { 363 struct vnode *vp; 364 int n; 365 366 /* count #vnodes held on mount list */ 367 for (n = 0, vp = mp->mnt_vnodelist.lh_first; 368 vp != NULLVP; 369 vp = vp->v_mntvnodes.le_next) 370 n++; 371 372 /* if this is unchanged then stop */ 373 if (n == freeing) 374 break; 375 376 /* otherwise try once more time */ 377 freeing = n; 378 } 379 380 /* 381 * Ok, now that we've tried doing it gently, get out the hammer. 382 */ 383 384 if (mntflags & MNT_FORCE) 385 vflush(mp, um_rootvp, FORCECLOSE); 386 387 388 /* At this point the root vnode should have a single reference */ 389 if (um_rootvp->v_usecount > 1) { 390 vput(um_rootvp); 391 return (EBUSY); 392 } 393 394 #ifdef UNION_DIAGNOSTIC 395 vprint("union root", um_rootvp); 396 #endif 397 /* 398 * Discard references to upper and lower target vnodes. 399 */ 400 if (um->um_lowervp) 401 vrele(um->um_lowervp); 402 vrele(um->um_uppervp); 403 crfree(um->um_cred); 404 /* 405 * Release reference on underlying root vnode 406 */ 407 vput(um_rootvp); 408 /* 409 * And blow it away for future re-use 410 */ 411 vgone(um_rootvp); 412 /* 413 * Finally, throw away the union_mount structure 414 */ 415 free(mp->mnt_data, M_UFSMNT); /* XXX */ 416 mp->mnt_data = 0; 417 return (0); 418 } 419 420 int 421 union_root(mp, vpp) 422 struct mount *mp; 423 struct vnode **vpp; 424 { 425 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 426 int error; 427 int loselock; 428 429 /* 430 * Return locked reference to root. 431 */ 432 VREF(um->um_uppervp); 433 if ((um->um_op == UNMNT_BELOW) && 434 VOP_ISLOCKED(um->um_uppervp)) { 435 loselock = 1; 436 } else { 437 vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); 438 loselock = 0; 439 } 440 if (um->um_lowervp) 441 VREF(um->um_lowervp); 442 error = union_allocvp(vpp, mp, 443 (struct vnode *) 0, 444 (struct vnode *) 0, 445 (struct componentname *) 0, 446 um->um_uppervp, 447 um->um_lowervp, 448 1); 449 450 if (error) { 451 if (!loselock) 452 VOP_UNLOCK(um->um_uppervp, 0); 453 vrele(um->um_uppervp); 454 if (um->um_lowervp) 455 vrele(um->um_lowervp); 456 } else { 457 if (loselock) 458 VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; 459 } 460 461 return (error); 462 } 463 464 /*ARGSUSED*/ 465 int 466 union_quotactl(mp, cmd, uid, arg, p) 467 struct mount *mp; 468 int cmd; 469 uid_t uid; 470 void *arg; 471 struct proc *p; 472 { 473 474 return (EOPNOTSUPP); 475 } 476 477 int 478 union_statvfs(mp, sbp, p) 479 struct mount *mp; 480 struct statvfs *sbp; 481 struct proc *p; 482 { 483 int error; 484 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 485 struct statvfs *sbuf = malloc(sizeof(*sbuf), M_TEMP, M_WAITOK); 486 unsigned long lbsize; 487 488 #ifdef UNION_DIAGNOSTIC 489 printf("union_statvfs(mp = %p, lvp = %p, uvp = %p)\n", mp, 490 um->um_lowervp, um->um_uppervp); 491 #endif 492 493 if (um->um_lowervp) { 494 error = VFS_STATVFS(um->um_lowervp->v_mount, sbuf, p); 495 if (error) 496 goto done; 497 } 498 499 /* now copy across the "interesting" information and fake the rest */ 500 lbsize = sbuf->f_bsize; 501 sbp->f_blocks = sbuf->f_blocks - sbuf->f_bfree; 502 sbp->f_files = sbuf->f_files - sbuf->f_ffree; 503 504 error = VFS_STATVFS(um->um_uppervp->v_mount, sbuf, p); 505 if (error) 506 goto done; 507 508 sbp->f_flag = sbuf->f_flag; 509 sbp->f_bsize = sbuf->f_bsize; 510 sbp->f_frsize = sbuf->f_frsize; 511 sbp->f_iosize = sbuf->f_iosize; 512 513 /* 514 * The "total" fields count total resources in all layers, 515 * the "free" fields count only those resources which are 516 * free in the upper layer (since only the upper layer 517 * is writable). 518 */ 519 520 if (sbuf->f_bsize != lbsize) 521 sbp->f_blocks = sbp->f_blocks * lbsize / sbuf->f_bsize; 522 sbp->f_blocks += sbuf->f_blocks; 523 sbp->f_bfree = sbuf->f_bfree; 524 sbp->f_bavail = sbuf->f_bavail; 525 sbp->f_bresvd = sbuf->f_bresvd; 526 sbp->f_files += sbuf->f_files; 527 sbp->f_ffree = sbuf->f_ffree; 528 sbp->f_favail = sbuf->f_favail; 529 sbp->f_fresvd = sbuf->f_fresvd; 530 531 copy_statvfs_info(sbp, mp); 532 done: 533 free(sbuf, M_TEMP); 534 return error; 535 } 536 537 /*ARGSUSED*/ 538 int 539 union_sync(mp, waitfor, cred, p) 540 struct mount *mp; 541 int waitfor; 542 struct ucred *cred; 543 struct proc *p; 544 { 545 546 /* 547 * XXX - Assumes no data cached at union layer. 548 */ 549 return (0); 550 } 551 552 /*ARGSUSED*/ 553 int 554 union_vget(mp, ino, vpp) 555 struct mount *mp; 556 ino_t ino; 557 struct vnode **vpp; 558 { 559 560 return (EOPNOTSUPP); 561 } 562 563 /*ARGSUSED*/ 564 int 565 union_fhtovp(mp, fidp, vpp) 566 struct mount *mp; 567 struct fid *fidp; 568 struct vnode **vpp; 569 { 570 571 return (EOPNOTSUPP); 572 } 573 574 /*ARGSUSED*/ 575 int 576 union_checkexp(mp, nam, exflagsp, credanonp) 577 struct mount *mp; 578 struct mbuf *nam; 579 int *exflagsp; 580 struct ucred **credanonp; 581 { 582 583 return (EOPNOTSUPP); 584 } 585 586 /*ARGSUSED*/ 587 int 588 union_vptofh(vp, fhp) 589 struct vnode *vp; 590 struct fid *fhp; 591 { 592 593 return (EOPNOTSUPP); 594 } 595 596 SYSCTL_SETUP(sysctl_vfs_union_setup, "sysctl vfs.union subtree setup") 597 { 598 599 sysctl_createv(clog, 0, NULL, NULL, 600 CTLFLAG_PERMANENT, 601 CTLTYPE_NODE, "vfs", NULL, 602 NULL, 0, NULL, 0, 603 CTL_VFS, CTL_EOL); 604 sysctl_createv(clog, 0, NULL, NULL, 605 CTLFLAG_PERMANENT, 606 CTLTYPE_NODE, "union", 607 SYSCTL_DESCR("Union file system"), 608 NULL, 0, NULL, 0, 609 CTL_VFS, 15, CTL_EOL); 610 /* 611 * XXX the "15" above could be dynamic, thereby eliminating 612 * one more instance of the "number to vfs" mapping problem, 613 * but "15" is the order as taken from sys/mount.h 614 */ 615 } 616 617 extern const struct vnodeopv_desc union_vnodeop_opv_desc; 618 619 const struct vnodeopv_desc * const union_vnodeopv_descs[] = { 620 &union_vnodeop_opv_desc, 621 NULL, 622 }; 623 624 struct vfsops union_vfsops = { 625 MOUNT_UNION, 626 union_mount, 627 union_start, 628 union_unmount, 629 union_root, 630 union_quotactl, 631 union_statvfs, 632 union_sync, 633 union_vget, 634 union_fhtovp, 635 union_vptofh, 636 union_init, 637 NULL, /* vfs_reinit */ 638 union_done, 639 NULL, 640 NULL, /* vfs_mountroot */ 641 union_checkexp, 642 layerfs_snapshot, 643 union_vnodeopv_descs, 644 }; 645
Indexes created Sun Oct 12 20:09:57 GMT 2025