union_vfsops.c revision 1.25.2.1.2.1
1 /* $NetBSD: union_vfsops.c,v 1.25.2.1.2.1 2006/01/08 15:45:15 riz 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 1.25.2.1.2.1 2006/01/08 15:45:15 riz 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 proc *)); 99 int union_start __P((struct mount *, int, struct proc *)); 100 int union_unmount __P((struct mount *, int, struct proc *)); 101 int union_root __P((struct mount *, struct vnode **)); 102 int union_quotactl __P((struct mount *, int, uid_t, void *, struct proc *)); 103 int union_statvfs __P((struct mount *, struct statvfs *, struct proc *)); 104 int union_sync __P((struct mount *, int, struct ucred *, struct proc *)); 105 int union_vget __P((struct mount *, ino_t, struct vnode **)); 106 int union_fhtovp __P((struct mount *, struct fid *, struct vnode **)); 107 int union_checkexp __P((struct mount *, struct mbuf *, int *, 108 struct ucred **)); 109 int union_vptofh __P((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 char *cp; 129 int len; 130 size_t size; 131 132 #ifdef UNION_DIAGNOSTIC 133 printf("union_mount(mp = %p)\n", mp); 134 #endif 135 136 if (mp->mnt_flag & MNT_GETARGS) { 137 um = MOUNTTOUNIONMOUNT(mp); 138 if (um == NULL) 139 return EIO; 140 args.target = NULL; 141 args.mntflags = um->um_op; 142 return copyout(&args, data, sizeof(args)); 143 } 144 /* 145 * Update is a no-op 146 */ 147 if (mp->mnt_flag & MNT_UPDATE) { 148 /* 149 * Need to provide. 150 * 1. a way to convert between rdonly and rdwr mounts. 151 * 2. support for nfs exports. 152 */ 153 error = EOPNOTSUPP; 154 goto bad; 155 } 156 157 /* 158 * Get argument 159 */ 160 error = copyin(data, &args, sizeof(struct union_args)); 161 if (error) 162 goto bad; 163 164 lowerrootvp = mp->mnt_vnodecovered; 165 VREF(lowerrootvp); 166 167 /* 168 * Find upper node. 169 */ 170 NDINIT(ndp, LOOKUP, FOLLOW, 171 UIO_USERSPACE, args.target, p); 172 173 if ((error = namei(ndp)) != 0) 174 goto bad; 175 176 upperrootvp = ndp->ni_vp; 177 178 if (upperrootvp->v_type != VDIR) { 179 error = EINVAL; 180 goto bad; 181 } 182 183 um = (struct union_mount *) malloc(sizeof(struct union_mount), 184 M_UFSMNT, M_WAITOK); /* XXX */ 185 186 /* 187 * Keep a held reference to the target vnodes. 188 * They are vrele'd in union_unmount. 189 * 190 * Depending on the _BELOW flag, the filesystems are 191 * viewed in a different order. In effect, this is the 192 * same as providing a mount under option to the mount syscall. 193 */ 194 195 um->um_op = args.mntflags & UNMNT_OPMASK; 196 switch (um->um_op) { 197 case UNMNT_ABOVE: 198 um->um_lowervp = lowerrootvp; 199 um->um_uppervp = upperrootvp; 200 break; 201 202 case UNMNT_BELOW: 203 um->um_lowervp = upperrootvp; 204 um->um_uppervp = lowerrootvp; 205 break; 206 207 case UNMNT_REPLACE: 208 vrele(lowerrootvp); 209 lowerrootvp = NULLVP; 210 um->um_uppervp = upperrootvp; 211 um->um_lowervp = lowerrootvp; 212 break; 213 214 default: 215 error = EINVAL; 216 goto bad; 217 } 218 219 /* 220 * Unless the mount is readonly, ensure that the top layer 221 * supports whiteout operations 222 */ 223 if ((mp->mnt_flag & MNT_RDONLY) == 0) { 224 error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP); 225 if (error) 226 goto bad; 227 } 228 229 um->um_cred = p->p_ucred; 230 crhold(um->um_cred); 231 um->um_cmode = UN_DIRMODE &~ p->p_cwdi->cwdi_cmask; 232 233 /* 234 * Depending on what you think the MNT_LOCAL flag might mean, 235 * you may want the && to be || on the conditional below. 236 * At the moment it has been defined that the filesystem is 237 * only local if it is all local, ie the MNT_LOCAL flag implies 238 * that the entire namespace is local. If you think the MNT_LOCAL 239 * flag implies that some of the files might be stored locally 240 * then you will want to change the conditional. 241 */ 242 if (um->um_op == UNMNT_ABOVE) { 243 if (((um->um_lowervp == NULLVP) || 244 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) && 245 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL)) 246 mp->mnt_flag |= MNT_LOCAL; 247 } 248 249 /* 250 * Copy in the upper layer's RDONLY flag. This is for the benefit 251 * of lookup() which explicitly checks the flag, rather than asking 252 * the filesystem for it's own opinion. This means, that an update 253 * mount of the underlying filesystem to go from rdonly to rdwr 254 * will leave the unioned view as read-only. 255 */ 256 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY); 257 258 mp->mnt_data = um; 259 mp->mnt_leaf = um->um_uppervp->v_mount->mnt_leaf; 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 int freeing; 343 344 #ifdef UNION_DIAGNOSTIC 345 printf("union_unmount(mp = %p)\n", mp); 346 #endif 347 348 /* 349 * Keep flushing vnodes from the mount list. 350 * This is needed because of the un_pvp held 351 * reference to the parent vnode. 352 * If more vnodes have been freed on a given pass, 353 * the try again. The loop will iterate at most 354 * (d) times, where (d) is the maximum tree depth 355 * in the filesystem. 356 */ 357 for (freeing = 0; vflush(mp, NULL, 0) != 0;) { 358 struct vnode *vp; 359 int n; 360 361 /* count #vnodes held on mount list */ 362 for (n = 0, vp = mp->mnt_vnodelist.lh_first; 363 vp != NULLVP; 364 vp = vp->v_mntvnodes.le_next) 365 n++; 366 367 /* if this is unchanged then stop */ 368 if (n == freeing) 369 break; 370 371 /* otherwise try once more time */ 372 freeing = n; 373 } 374 375 /* 376 * Ok, now that we've tried doing it gently, get out the hammer. 377 */ 378 379 if (mntflags & MNT_FORCE) 380 vflush(mp, NULL, FORCECLOSE); 381 382 383 /* 384 * Discard references to upper and lower target vnodes. 385 */ 386 if (um->um_lowervp) 387 vrele(um->um_lowervp); 388 vrele(um->um_uppervp); 389 crfree(um->um_cred); 390 /* 391 * Finally, throw away the union_mount structure 392 */ 393 free(mp->mnt_data, M_UFSMNT); /* XXX */ 394 mp->mnt_data = 0; 395 return (0); 396 } 397 398 int 399 union_root(mp, vpp) 400 struct mount *mp; 401 struct vnode **vpp; 402 { 403 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 404 int error; 405 int loselock; 406 407 /* 408 * Return locked reference to root. 409 */ 410 VREF(um->um_uppervp); 411 if ((um->um_op == UNMNT_BELOW) && 412 VOP_ISLOCKED(um->um_uppervp)) { 413 loselock = 1; 414 } else { 415 vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); 416 loselock = 0; 417 } 418 if (um->um_lowervp) 419 VREF(um->um_lowervp); 420 error = union_allocvp(vpp, mp, 421 (struct vnode *) 0, 422 (struct vnode *) 0, 423 (struct componentname *) 0, 424 um->um_uppervp, 425 um->um_lowervp, 426 1); 427 428 if (error) { 429 if (!loselock) 430 VOP_UNLOCK(um->um_uppervp, 0); 431 vrele(um->um_uppervp); 432 if (um->um_lowervp) 433 vrele(um->um_lowervp); 434 } else { 435 if (loselock) 436 VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; 437 } 438 439 return (error); 440 } 441 442 /*ARGSUSED*/ 443 int 444 union_quotactl(mp, cmd, uid, arg, p) 445 struct mount *mp; 446 int cmd; 447 uid_t uid; 448 void *arg; 449 struct proc *p; 450 { 451 452 return (EOPNOTSUPP); 453 } 454 455 int 456 union_statvfs(mp, sbp, p) 457 struct mount *mp; 458 struct statvfs *sbp; 459 struct proc *p; 460 { 461 int error; 462 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 463 struct statvfs *sbuf = malloc(sizeof(*sbuf), M_TEMP, M_WAITOK | M_ZERO); 464 unsigned long lbsize; 465 466 #ifdef UNION_DIAGNOSTIC 467 printf("union_statvfs(mp = %p, lvp = %p, uvp = %p)\n", mp, 468 um->um_lowervp, um->um_uppervp); 469 #endif 470 471 if (um->um_lowervp) { 472 error = VFS_STATVFS(um->um_lowervp->v_mount, sbuf, p); 473 if (error) 474 goto done; 475 } 476 477 /* now copy across the "interesting" information and fake the rest */ 478 lbsize = sbuf->f_bsize; 479 sbp->f_blocks = sbuf->f_blocks - sbuf->f_bfree; 480 sbp->f_files = sbuf->f_files - sbuf->f_ffree; 481 482 error = VFS_STATVFS(um->um_uppervp->v_mount, sbuf, p); 483 if (error) 484 goto done; 485 486 sbp->f_flag = sbuf->f_flag; 487 sbp->f_bsize = sbuf->f_bsize; 488 sbp->f_frsize = sbuf->f_frsize; 489 sbp->f_iosize = sbuf->f_iosize; 490 491 /* 492 * The "total" fields count total resources in all layers, 493 * the "free" fields count only those resources which are 494 * free in the upper layer (since only the upper layer 495 * is writable). 496 */ 497 498 if (sbuf->f_bsize != lbsize) 499 sbp->f_blocks = sbp->f_blocks * lbsize / sbuf->f_bsize; 500 sbp->f_blocks += sbuf->f_blocks; 501 sbp->f_bfree = sbuf->f_bfree; 502 sbp->f_bavail = sbuf->f_bavail; 503 sbp->f_bresvd = sbuf->f_bresvd; 504 sbp->f_files += sbuf->f_files; 505 sbp->f_ffree = sbuf->f_ffree; 506 sbp->f_favail = sbuf->f_favail; 507 sbp->f_fresvd = sbuf->f_fresvd; 508 509 copy_statvfs_info(sbp, mp); 510 done: 511 free(sbuf, M_TEMP); 512 return error; 513 } 514 515 /*ARGSUSED*/ 516 int 517 union_sync(mp, waitfor, cred, p) 518 struct mount *mp; 519 int waitfor; 520 struct ucred *cred; 521 struct proc *p; 522 { 523 524 /* 525 * XXX - Assumes no data cached at union layer. 526 */ 527 return (0); 528 } 529 530 /*ARGSUSED*/ 531 int 532 union_vget(mp, ino, vpp) 533 struct mount *mp; 534 ino_t ino; 535 struct vnode **vpp; 536 { 537 538 return (EOPNOTSUPP); 539 } 540 541 /*ARGSUSED*/ 542 int 543 union_fhtovp(mp, fidp, vpp) 544 struct mount *mp; 545 struct fid *fidp; 546 struct vnode **vpp; 547 { 548 549 return (EOPNOTSUPP); 550 } 551 552 /*ARGSUSED*/ 553 int 554 union_checkexp(mp, nam, exflagsp, credanonp) 555 struct mount *mp; 556 struct mbuf *nam; 557 int *exflagsp; 558 struct ucred **credanonp; 559 { 560 561 return (EOPNOTSUPP); 562 } 563 564 /*ARGSUSED*/ 565 int 566 union_vptofh(vp, fhp) 567 struct vnode *vp; 568 struct fid *fhp; 569 { 570 571 return (EOPNOTSUPP); 572 } 573 574 SYSCTL_SETUP(sysctl_vfs_union_setup, "sysctl vfs.union subtree setup") 575 { 576 577 sysctl_createv(clog, 0, NULL, NULL, 578 CTLFLAG_PERMANENT, 579 CTLTYPE_NODE, "vfs", NULL, 580 NULL, 0, NULL, 0, 581 CTL_VFS, CTL_EOL); 582 sysctl_createv(clog, 0, NULL, NULL, 583 CTLFLAG_PERMANENT, 584 CTLTYPE_NODE, "union", 585 SYSCTL_DESCR("Union file system"), 586 NULL, 0, NULL, 0, 587 CTL_VFS, 15, CTL_EOL); 588 /* 589 * XXX the "15" above could be dynamic, thereby eliminating 590 * one more instance of the "number to vfs" mapping problem, 591 * but "15" is the order as taken from sys/mount.h 592 */ 593 } 594 595 extern const struct vnodeopv_desc union_vnodeop_opv_desc; 596 597 const struct vnodeopv_desc * const union_vnodeopv_descs[] = { 598 &union_vnodeop_opv_desc, 599 NULL, 600 }; 601 602 struct vfsops union_vfsops = { 603 MOUNT_UNION, 604 union_mount, 605 union_start, 606 union_unmount, 607 union_root, 608 union_quotactl, 609 union_statvfs, 610 union_sync, 611 union_vget, 612 union_fhtovp, 613 union_vptofh, 614 union_init, 615 NULL, /* vfs_reinit */ 616 union_done, 617 NULL, 618 NULL, /* vfs_mountroot */ 619 union_checkexp, 620 (int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp, 621 vfs_stdextattrctl, 622 union_vnodeopv_descs, 623 }; 624
Indexes created Mon Oct 13 16:09:52 GMT 2025