union_vfsops.c revision 1.8.2.9
1 /* $NetBSD: union_vfsops.c,v 1.8.2.9 2005/11/10 14:09:44 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 1.8.2.9 2005/11/10 14:09:44 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(struct mount *, const char *, void *, struct nameidata *, 98 struct lwp *); 99 int union_start(struct mount *, int, struct lwp *); 100 int union_unmount(struct mount *, int, struct lwp *); 101 int union_root(struct mount *, struct vnode **); 102 int union_quotactl(struct mount *, int, uid_t, void *, struct lwp *); 103 int union_statvfs(struct mount *, struct statvfs *, struct lwp *); 104 int union_sync(struct mount *, int, struct ucred *, struct lwp *); 105 int union_vget(struct mount *, ino_t, struct vnode **); 106 107 /* 108 * Mount union filesystem 109 */ 110 int 111 union_mount(mp, path, data, ndp, l) 112 struct mount *mp; 113 const char *path; 114 void *data; 115 struct nameidata *ndp; 116 struct lwp *l; 117 { 118 int error = 0; 119 struct union_args args; 120 struct vnode *lowerrootvp = NULLVP; 121 struct vnode *upperrootvp = NULLVP; 122 struct union_mount *um = 0; 123 struct ucred *cred = 0; 124 const char *cp; 125 char *xp; 126 int len; 127 size_t size; 128 129 #ifdef UNION_DIAGNOSTIC 130 printf("union_mount(mp = %p)\n", mp); 131 #endif 132 133 if (mp->mnt_flag & MNT_GETARGS) { 134 um = MOUNTTOUNIONMOUNT(mp); 135 if (um == NULL) 136 return EIO; 137 args.target = NULL; 138 args.mntflags = um->um_op; 139 return copyout(&args, data, sizeof(args)); 140 } 141 /* 142 * Update is a no-op 143 */ 144 if (mp->mnt_flag & MNT_UPDATE) { 145 /* 146 * Need to provide. 147 * 1. a way to convert between rdonly and rdwr mounts. 148 * 2. support for nfs exports. 149 */ 150 error = EOPNOTSUPP; 151 goto bad; 152 } 153 154 /* 155 * Get argument 156 */ 157 error = copyin(data, &args, sizeof(struct union_args)); 158 if (error) 159 goto bad; 160 161 lowerrootvp = mp->mnt_vnodecovered; 162 VREF(lowerrootvp); 163 164 /* 165 * Find upper node. 166 */ 167 NDINIT(ndp, LOOKUP, FOLLOW, 168 UIO_USERSPACE, args.target, l); 169 170 if ((error = namei(ndp)) != 0) 171 goto bad; 172 173 upperrootvp = ndp->ni_vp; 174 175 if (upperrootvp->v_type != VDIR) { 176 error = EINVAL; 177 goto bad; 178 } 179 180 um = (struct union_mount *) malloc(sizeof(struct union_mount), 181 M_UFSMNT, M_WAITOK); /* XXX */ 182 183 /* 184 * Keep a held reference to the target vnodes. 185 * They are vrele'd in union_unmount. 186 * 187 * Depending on the _BELOW flag, the filesystems are 188 * viewed in a different order. In effect, this is the 189 * same as providing a mount under option to the mount syscall. 190 */ 191 192 um->um_op = args.mntflags & UNMNT_OPMASK; 193 switch (um->um_op) { 194 case UNMNT_ABOVE: 195 um->um_lowervp = lowerrootvp; 196 um->um_uppervp = upperrootvp; 197 break; 198 199 case UNMNT_BELOW: 200 um->um_lowervp = upperrootvp; 201 um->um_uppervp = lowerrootvp; 202 break; 203 204 case UNMNT_REPLACE: 205 vrele(lowerrootvp); 206 lowerrootvp = NULLVP; 207 um->um_uppervp = upperrootvp; 208 um->um_lowervp = lowerrootvp; 209 break; 210 211 default: 212 error = EINVAL; 213 goto bad; 214 } 215 216 /* 217 * Unless the mount is readonly, ensure that the top layer 218 * supports whiteout operations 219 */ 220 if ((mp->mnt_flag & MNT_RDONLY) == 0) { 221 error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP); 222 if (error) 223 goto bad; 224 } 225 226 um->um_cred = l->l_proc->p_ucred; 227 crhold(um->um_cred); 228 um->um_cmode = UN_DIRMODE &~ l->l_proc->p_cwdi->cwdi_cmask; 229 230 /* 231 * Depending on what you think the MNT_LOCAL flag might mean, 232 * you may want the && to be || on the conditional below. 233 * At the moment it has been defined that the filesystem is 234 * only local if it is all local, ie the MNT_LOCAL flag implies 235 * that the entire namespace is local. If you think the MNT_LOCAL 236 * flag implies that some of the files might be stored locally 237 * then you will want to change the conditional. 238 */ 239 if (um->um_op == UNMNT_ABOVE) { 240 if (((um->um_lowervp == NULLVP) || 241 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) && 242 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL)) 243 mp->mnt_flag |= MNT_LOCAL; 244 } 245 246 /* 247 * Copy in the upper layer's RDONLY flag. This is for the benefit 248 * of lookup() which explicitly checks the flag, rather than asking 249 * the filesystem for it's own opinion. This means, that an update 250 * mount of the underlying filesystem to go from rdonly to rdwr 251 * will leave the unioned view as read-only. 252 */ 253 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY); 254 255 mp->mnt_data = um; 256 mp->mnt_leaf = um->um_uppervp->v_mount->mnt_leaf; 257 vfs_getnewfsid(mp); 258 259 error = set_statvfs_info( path, UIO_USERSPACE, NULL, UIO_USERSPACE, 260 mp, l); 261 if (error) 262 goto bad; 263 264 switch (um->um_op) { 265 case UNMNT_ABOVE: 266 cp = "<above>:"; 267 break; 268 case UNMNT_BELOW: 269 cp = "<below>:"; 270 break; 271 case UNMNT_REPLACE: 272 cp = ""; 273 break; 274 default: 275 cp = "<invalid>:"; 276 #ifdef DIAGNOSTIC 277 panic("union_mount: bad um_op"); 278 #endif 279 break; 280 } 281 len = strlen(cp); 282 memcpy(mp->mnt_stat.f_mntfromname, cp, len); 283 284 xp = mp->mnt_stat.f_mntfromname + len; 285 len = MNAMELEN - len; 286 287 (void) copyinstr(args.target, xp, len - 1, &size); 288 memset(xp + size, 0, len - size); 289 290 #ifdef UNION_DIAGNOSTIC 291 printf("union_mount: from %s, on %s\n", 292 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 293 #endif 294 295 /* Setup the readdir hook if it's not set already */ 296 if (!vn_union_readdir_hook) 297 vn_union_readdir_hook = union_readdirhook; 298 299 return (0); 300 301 bad: 302 if (um) 303 free(um, M_UFSMNT); 304 if (cred) 305 crfree(cred); 306 if (upperrootvp) 307 vrele(upperrootvp); 308 if (lowerrootvp) 309 vrele(lowerrootvp); 310 return (error); 311 } 312 313 /* 314 * VFS start. Nothing needed here - the start routine 315 * on the underlying filesystem(s) will have been called 316 * when that filesystem was mounted. 317 */ 318 /*ARGSUSED*/ 319 int 320 union_start(mp, flags, l) 321 struct mount *mp; 322 int flags; 323 struct lwp *l; 324 { 325 326 return (0); 327 } 328 329 /* 330 * Free reference to union layer 331 */ 332 int 333 union_unmount(mp, mntflags, l) 334 struct mount *mp; 335 int mntflags; 336 struct lwp *l; 337 { 338 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 339 struct vnode *um_rootvp; 340 int error; 341 int freeing; 342 343 #ifdef UNION_DIAGNOSTIC 344 printf("union_unmount(mp = %p)\n", mp); 345 #endif 346 347 if ((error = union_root(mp, &um_rootvp)) != 0) 348 return (error); 349 350 /* 351 * Keep flushing vnodes from the mount list. 352 * This is needed because of the un_pvp held 353 * reference to the parent vnode. 354 * If more vnodes have been freed on a given pass, 355 * the try again. The loop will iterate at most 356 * (d) times, where (d) is the maximum tree depth 357 * in the filesystem. 358 */ 359 for (freeing = 0; vflush(mp, um_rootvp, 0) != 0;) { 360 struct vnode *vp; 361 int n; 362 363 /* count #vnodes held on mount list */ 364 for (n = 0, vp = mp->mnt_vnodelist.lh_first; 365 vp != NULLVP; 366 vp = vp->v_mntvnodes.le_next) 367 n++; 368 369 /* if this is unchanged then stop */ 370 if (n == freeing) 371 break; 372 373 /* otherwise try once more time */ 374 freeing = n; 375 } 376 377 /* 378 * Ok, now that we've tried doing it gently, get out the hammer. 379 */ 380 381 if (mntflags & MNT_FORCE) 382 vflush(mp, um_rootvp, FORCECLOSE); 383 384 385 /* At this point the root vnode should have a single reference */ 386 if (um_rootvp->v_usecount > 1) { 387 vput(um_rootvp); 388 return (EBUSY); 389 } 390 391 #ifdef UNION_DIAGNOSTIC 392 vprint("union root", um_rootvp); 393 #endif 394 /* 395 * Discard references to upper and lower target vnodes. 396 */ 397 if (um->um_lowervp) 398 vrele(um->um_lowervp); 399 vrele(um->um_uppervp); 400 crfree(um->um_cred); 401 /* 402 * Release reference on underlying root vnode 403 */ 404 vput(um_rootvp); 405 /* 406 * And blow it away for future re-use 407 */ 408 vgone(um_rootvp); 409 /* 410 * Finally, throw away the union_mount structure 411 */ 412 free(mp->mnt_data, M_UFSMNT); /* XXX */ 413 mp->mnt_data = 0; 414 return (0); 415 } 416 417 int 418 union_root(mp, vpp) 419 struct mount *mp; 420 struct vnode **vpp; 421 { 422 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 423 int error; 424 int loselock; 425 426 /* 427 * Return locked reference to root. 428 */ 429 VREF(um->um_uppervp); 430 if ((um->um_op == UNMNT_BELOW) && 431 VOP_ISLOCKED(um->um_uppervp)) { 432 loselock = 1; 433 } else { 434 vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); 435 loselock = 0; 436 } 437 if (um->um_lowervp) 438 VREF(um->um_lowervp); 439 error = union_allocvp(vpp, mp, 440 (struct vnode *) 0, 441 (struct vnode *) 0, 442 (struct componentname *) 0, 443 um->um_uppervp, 444 um->um_lowervp, 445 1); 446 447 if (error) { 448 if (!loselock) 449 VOP_UNLOCK(um->um_uppervp, 0); 450 vrele(um->um_uppervp); 451 if (um->um_lowervp) 452 vrele(um->um_lowervp); 453 } else { 454 if (loselock) 455 VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; 456 } 457 458 return (error); 459 } 460 461 /*ARGSUSED*/ 462 int 463 union_quotactl(mp, cmd, uid, arg, l) 464 struct mount *mp; 465 int cmd; 466 uid_t uid; 467 void *arg; 468 struct lwp *l; 469 { 470 471 return (EOPNOTSUPP); 472 } 473 474 int 475 union_statvfs(mp, sbp, l) 476 struct mount *mp; 477 struct statvfs *sbp; 478 struct lwp *l; 479 { 480 int error; 481 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 482 struct statvfs *sbuf = malloc(sizeof(*sbuf), M_TEMP, M_WAITOK | M_ZERO); 483 unsigned long lbsize; 484 485 #ifdef UNION_DIAGNOSTIC 486 printf("union_statvfs(mp = %p, lvp = %p, uvp = %p)\n", mp, 487 um->um_lowervp, um->um_uppervp); 488 #endif 489 490 if (um->um_lowervp) { 491 error = VFS_STATVFS(um->um_lowervp->v_mount, sbuf, l); 492 if (error) 493 goto done; 494 } 495 496 /* now copy across the "interesting" information and fake the rest */ 497 lbsize = sbuf->f_bsize; 498 sbp->f_blocks = sbuf->f_blocks - sbuf->f_bfree; 499 sbp->f_files = sbuf->f_files - sbuf->f_ffree; 500 501 error = VFS_STATVFS(um->um_uppervp->v_mount, sbuf, l); 502 if (error) 503 goto done; 504 505 sbp->f_flag = sbuf->f_flag; 506 sbp->f_bsize = sbuf->f_bsize; 507 sbp->f_frsize = sbuf->f_frsize; 508 sbp->f_iosize = sbuf->f_iosize; 509 510 /* 511 * The "total" fields count total resources in all layers, 512 * the "free" fields count only those resources which are 513 * free in the upper layer (since only the upper layer 514 * is writable). 515 */ 516 517 if (sbuf->f_bsize != lbsize) 518 sbp->f_blocks = sbp->f_blocks * lbsize / sbuf->f_bsize; 519 sbp->f_blocks += sbuf->f_blocks; 520 sbp->f_bfree = sbuf->f_bfree; 521 sbp->f_bavail = sbuf->f_bavail; 522 sbp->f_bresvd = sbuf->f_bresvd; 523 sbp->f_files += sbuf->f_files; 524 sbp->f_ffree = sbuf->f_ffree; 525 sbp->f_favail = sbuf->f_favail; 526 sbp->f_fresvd = sbuf->f_fresvd; 527 528 copy_statvfs_info(sbp, mp); 529 done: 530 free(sbuf, M_TEMP); 531 return error; 532 } 533 534 /*ARGSUSED*/ 535 int 536 union_sync(mp, waitfor, cred, l) 537 struct mount *mp; 538 int waitfor; 539 struct ucred *cred; 540 struct lwp *l; 541 { 542 543 /* 544 * XXX - Assumes no data cached at union layer. 545 */ 546 return (0); 547 } 548 549 /*ARGSUSED*/ 550 int 551 union_vget(mp, ino, vpp) 552 struct mount *mp; 553 ino_t ino; 554 struct vnode **vpp; 555 { 556 557 return (EOPNOTSUPP); 558 } 559 560 SYSCTL_SETUP(sysctl_vfs_union_setup, "sysctl vfs.union subtree setup") 561 { 562 563 sysctl_createv(clog, 0, NULL, NULL, 564 CTLFLAG_PERMANENT, 565 CTLTYPE_NODE, "vfs", NULL, 566 NULL, 0, NULL, 0, 567 CTL_VFS, CTL_EOL); 568 sysctl_createv(clog, 0, NULL, NULL, 569 CTLFLAG_PERMANENT, 570 CTLTYPE_NODE, "union", 571 SYSCTL_DESCR("Union file system"), 572 NULL, 0, NULL, 0, 573 CTL_VFS, 15, CTL_EOL); 574 /* 575 * XXX the "15" above could be dynamic, thereby eliminating 576 * one more instance of the "number to vfs" mapping problem, 577 * but "15" is the order as taken from sys/mount.h 578 */ 579 } 580 581 extern const struct vnodeopv_desc union_vnodeop_opv_desc; 582 583 const struct vnodeopv_desc * const union_vnodeopv_descs[] = { 584 &union_vnodeop_opv_desc, 585 NULL, 586 }; 587 588 struct vfsops union_vfsops = { 589 MOUNT_UNION, 590 union_mount, 591 union_start, 592 union_unmount, 593 union_root, 594 union_quotactl, 595 union_statvfs, 596 union_sync, 597 union_vget, 598 NULL, /* vfs_fhtovp */ 599 NULL, /* vfs_vptofh */ 600 union_init, 601 NULL, /* vfs_reinit */ 602 union_done, 603 NULL, /* vfs_mountroot */ 604 (int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp, 605 vfs_stdextattrctl, 606 union_vnodeopv_descs, 607 }; 608 VFS_ATTACH(union_vfsops); 609
Indexes created Mon Oct 13 01:09:56 GMT 2025