union_vnops.c revision 1.23
1 /* $NetBSD: union_vnops.c,v 1.23 2007/11/26 19:01:58 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 1992, 1993, 1994, 1995 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed 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_vnops.c 8.33 (Berkeley) 7/31/95 35 */ 36 37 /* 38 * Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry. 39 * 40 * This code is derived from software contributed to Berkeley by 41 * Jan-Simon Pendry. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. All advertising materials mentioning features or use of this software 52 * must display the following acknowledgement: 53 * This product includes software developed by the University of 54 * California, Berkeley and its contributors. 55 * 4. Neither the name of the University nor the names of its contributors 56 * may be used to endorse or promote products derived from this software 57 * without specific prior written permission. 58 * 59 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 60 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 61 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 62 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 63 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 64 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 65 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 66 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 67 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 68 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 69 * SUCH DAMAGE. 70 * 71 * @(#)union_vnops.c 8.33 (Berkeley) 7/31/95 72 */ 73 74 #include <sys/cdefs.h> 75 __KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.23 2007/11/26 19:01:58 pooka Exp $"); 76 77 #include <sys/param.h> 78 #include <sys/systm.h> 79 #include <sys/proc.h> 80 #include <sys/file.h> 81 #include <sys/time.h> 82 #include <sys/stat.h> 83 #include <sys/vnode.h> 84 #include <sys/mount.h> 85 #include <sys/namei.h> 86 #include <sys/malloc.h> 87 #include <sys/buf.h> 88 #include <sys/queue.h> 89 #include <sys/lock.h> 90 #include <sys/kauth.h> 91 92 #include <fs/union/union.h> 93 #include <miscfs/genfs/genfs.h> 94 95 int union_lookup(void *); 96 int union_create(void *); 97 int union_whiteout(void *); 98 int union_mknod(void *); 99 int union_open(void *); 100 int union_close(void *); 101 int union_access(void *); 102 int union_getattr(void *); 103 int union_setattr(void *); 104 int union_read(void *); 105 int union_write(void *); 106 int union_lease(void *); 107 int union_ioctl(void *); 108 int union_poll(void *); 109 int union_revoke(void *); 110 int union_mmap(void *); 111 int union_fsync(void *); 112 int union_seek(void *); 113 int union_remove(void *); 114 int union_link(void *); 115 int union_rename(void *); 116 int union_mkdir(void *); 117 int union_rmdir(void *); 118 int union_symlink(void *); 119 int union_readdir(void *); 120 int union_readlink(void *); 121 int union_abortop(void *); 122 int union_inactive(void *); 123 int union_reclaim(void *); 124 int union_lock(void *); 125 int union_unlock(void *); 126 int union_bmap(void *); 127 int union_print(void *); 128 int union_islocked(void *); 129 int union_pathconf(void *); 130 int union_advlock(void *); 131 int union_strategy(void *); 132 int union_getpages(void *); 133 int union_putpages(void *); 134 int union_kqfilter(void *); 135 136 static void union_fixup(struct union_node *); 137 static int union_lookup1(struct vnode *, struct vnode **, 138 struct vnode **, struct componentname *); 139 140 141 /* 142 * Global vfs data structures 143 */ 144 int (**union_vnodeop_p)(void *); 145 const struct vnodeopv_entry_desc union_vnodeop_entries[] = { 146 { &vop_default_desc, vn_default_error }, 147 { &vop_lookup_desc, union_lookup }, /* lookup */ 148 { &vop_create_desc, union_create }, /* create */ 149 { &vop_whiteout_desc, union_whiteout }, /* whiteout */ 150 { &vop_mknod_desc, union_mknod }, /* mknod */ 151 { &vop_open_desc, union_open }, /* open */ 152 { &vop_close_desc, union_close }, /* close */ 153 { &vop_access_desc, union_access }, /* access */ 154 { &vop_getattr_desc, union_getattr }, /* getattr */ 155 { &vop_setattr_desc, union_setattr }, /* setattr */ 156 { &vop_read_desc, union_read }, /* read */ 157 { &vop_write_desc, union_write }, /* write */ 158 { &vop_lease_desc, union_lease }, /* lease */ 159 { &vop_ioctl_desc, union_ioctl }, /* ioctl */ 160 { &vop_poll_desc, union_poll }, /* select */ 161 { &vop_revoke_desc, union_revoke }, /* revoke */ 162 { &vop_mmap_desc, union_mmap }, /* mmap */ 163 { &vop_fsync_desc, union_fsync }, /* fsync */ 164 { &vop_seek_desc, union_seek }, /* seek */ 165 { &vop_remove_desc, union_remove }, /* remove */ 166 { &vop_link_desc, union_link }, /* link */ 167 { &vop_rename_desc, union_rename }, /* rename */ 168 { &vop_mkdir_desc, union_mkdir }, /* mkdir */ 169 { &vop_rmdir_desc, union_rmdir }, /* rmdir */ 170 { &vop_symlink_desc, union_symlink }, /* symlink */ 171 { &vop_readdir_desc, union_readdir }, /* readdir */ 172 { &vop_readlink_desc, union_readlink }, /* readlink */ 173 { &vop_abortop_desc, union_abortop }, /* abortop */ 174 { &vop_inactive_desc, union_inactive }, /* inactive */ 175 { &vop_reclaim_desc, union_reclaim }, /* reclaim */ 176 { &vop_lock_desc, union_lock }, /* lock */ 177 { &vop_unlock_desc, union_unlock }, /* unlock */ 178 { &vop_bmap_desc, union_bmap }, /* bmap */ 179 { &vop_strategy_desc, union_strategy }, /* strategy */ 180 { &vop_print_desc, union_print }, /* print */ 181 { &vop_islocked_desc, union_islocked }, /* islocked */ 182 { &vop_pathconf_desc, union_pathconf }, /* pathconf */ 183 { &vop_advlock_desc, union_advlock }, /* advlock */ 184 { &vop_getpages_desc, union_getpages }, /* getpages */ 185 { &vop_putpages_desc, union_putpages }, /* putpages */ 186 { &vop_kqfilter_desc, union_kqfilter }, /* kqfilter */ 187 #ifdef notdef 188 { &vop_bwrite_desc, union_bwrite }, /* bwrite */ 189 #endif 190 { NULL, NULL } 191 }; 192 const struct vnodeopv_desc union_vnodeop_opv_desc = 193 { &union_vnodeop_p, union_vnodeop_entries }; 194 195 #define FIXUP(un) { \ 196 if (((un)->un_flags & UN_ULOCK) == 0) { \ 197 union_fixup(un); \ 198 } \ 199 } 200 201 static void 202 union_fixup(un) 203 struct union_node *un; 204 { 205 206 vn_lock(un->un_uppervp, LK_EXCLUSIVE | LK_RETRY); 207 un->un_flags |= UN_ULOCK; 208 } 209 210 static int 211 union_lookup1(udvp, dvpp, vpp, cnp) 212 struct vnode *udvp; 213 struct vnode **dvpp; 214 struct vnode **vpp; 215 struct componentname *cnp; 216 { 217 int error; 218 struct vnode *tdvp; 219 struct vnode *dvp; 220 struct mount *mp; 221 222 dvp = *dvpp; 223 224 /* 225 * If stepping up the directory tree, check for going 226 * back across the mount point, in which case do what 227 * lookup would do by stepping back down the mount 228 * hierarchy. 229 */ 230 if (cnp->cn_flags & ISDOTDOT) { 231 while ((dvp != udvp) && (dvp->v_vflag & VV_ROOT)) { 232 /* 233 * Don't do the NOCROSSMOUNT check 234 * at this level. By definition, 235 * union fs deals with namespaces, not 236 * filesystems. 237 */ 238 tdvp = dvp; 239 *dvpp = dvp = dvp->v_mount->mnt_vnodecovered; 240 VOP_UNLOCK(tdvp, 0); 241 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 242 } 243 } 244 245 error = VOP_LOOKUP(dvp, &tdvp, cnp); 246 if (error) 247 return (error); 248 249 dvp = tdvp; 250 251 /* 252 * Lastly check if the current node is a mount point in 253 * which case walk up the mount hierarchy making sure not to 254 * bump into the root of the mount tree (ie. dvp != udvp). 255 */ 256 while (dvp != udvp && (dvp->v_type == VDIR) && 257 (mp = dvp->v_mountedhere)) { 258 259 if (vfs_busy(mp, 0, 0)) 260 continue; 261 262 vput(dvp); 263 error = VFS_ROOT(mp, &tdvp); 264 vfs_unbusy(mp); 265 if (error) { 266 return (error); 267 } 268 dvp = tdvp; 269 } 270 271 *vpp = dvp; 272 return (0); 273 } 274 275 int 276 union_lookup(v) 277 void *v; 278 { 279 struct vop_lookup_args /* { 280 struct vnodeop_desc *a_desc; 281 struct vnode *a_dvp; 282 struct vnode **a_vpp; 283 struct componentname *a_cnp; 284 } */ *ap = v; 285 int error; 286 int uerror, lerror; 287 struct vnode *uppervp, *lowervp; 288 struct vnode *upperdvp, *lowerdvp; 289 struct vnode *dvp = ap->a_dvp; 290 struct union_node *dun = VTOUNION(dvp); 291 struct componentname *cnp = ap->a_cnp; 292 struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); 293 kauth_cred_t saved_cred = NULL; 294 int iswhiteout; 295 struct vattr va; 296 297 #ifdef notyet 298 if (cnp->cn_namelen == 3 && 299 cnp->cn_nameptr[2] == '.' && 300 cnp->cn_nameptr[1] == '.' && 301 cnp->cn_nameptr[0] == '.') { 302 dvp = *ap->a_vpp = LOWERVP(ap->a_dvp); 303 if (dvp == NULLVP) 304 return (ENOENT); 305 VREF(dvp); 306 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 307 return (0); 308 } 309 #endif 310 311 if ((cnp->cn_flags & ISLASTCN) && 312 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 313 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 314 return (EROFS); 315 316 upperdvp = dun->un_uppervp; 317 lowerdvp = dun->un_lowervp; 318 uppervp = NULLVP; 319 lowervp = NULLVP; 320 iswhiteout = 0; 321 322 /* 323 * do the lookup in the upper level. 324 * if that level comsumes additional pathnames, 325 * then assume that something special is going 326 * on and just return that vnode. 327 */ 328 if (upperdvp != NULLVP) { 329 FIXUP(dun); 330 /* 331 * If we're doing `..' in the underlying filesystem, 332 * we must drop our lock on the union node before 333 * going up the tree in the lower file system--if we block 334 * on the lowervp lock, and that's held by someone else 335 * coming down the tree and who's waiting for our lock, 336 * we would be hosed. 337 */ 338 if (cnp->cn_flags & ISDOTDOT) { 339 /* retain lock on underlying VP */ 340 dun->un_flags |= UN_KLOCK; 341 VOP_UNLOCK(dvp, 0); 342 } 343 uerror = union_lookup1(um->um_uppervp, &upperdvp, 344 &uppervp, cnp); 345 346 if (cnp->cn_flags & ISDOTDOT) { 347 if (dun->un_uppervp == upperdvp) { 348 /* 349 * we got the underlying bugger back locked... 350 * now take back the union node lock. Since we 351 * hold the uppervp lock, we can diddle union 352 * locking flags at will. :) 353 */ 354 dun->un_flags |= UN_ULOCK; 355 } 356 /* 357 * if upperdvp got swapped out, it means we did 358 * some mount point magic, and we do not have 359 * dun->un_uppervp locked currently--so we get it 360 * locked here (don't set the UN_ULOCK flag). 361 */ 362 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 363 } 364 if (cnp->cn_consume != 0) { 365 *ap->a_vpp = uppervp; 366 return (uerror); 367 } 368 if (uerror == ENOENT || uerror == EJUSTRETURN) { 369 if (cnp->cn_flags & ISWHITEOUT) { 370 iswhiteout = 1; 371 } else if (lowerdvp != NULLVP) { 372 lerror = VOP_GETATTR(upperdvp, &va, 373 cnp->cn_cred); 374 if (lerror == 0 && (va.va_flags & OPAQUE)) 375 iswhiteout = 1; 376 } 377 } 378 } else { 379 uerror = ENOENT; 380 } 381 382 /* 383 * in a similar way to the upper layer, do the lookup 384 * in the lower layer. this time, if there is some 385 * component magic going on, then vput whatever we got 386 * back from the upper layer and return the lower vnode 387 * instead. 388 */ 389 if (lowerdvp != NULLVP && !iswhiteout) { 390 int nameiop; 391 392 vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY); 393 394 /* 395 * Only do a LOOKUP on the bottom node, since 396 * we won't be making changes to it anyway. 397 */ 398 nameiop = cnp->cn_nameiop; 399 cnp->cn_nameiop = LOOKUP; 400 if (um->um_op == UNMNT_BELOW) { 401 saved_cred = cnp->cn_cred; 402 cnp->cn_cred = um->um_cred; 403 } 404 405 /* 406 * we shouldn't have to worry about locking interactions 407 * between the lower layer and our union layer (w.r.t. 408 * `..' processing) because we don't futz with lowervp 409 * locks in the union-node instantiation code path. 410 */ 411 lerror = union_lookup1(um->um_lowervp, &lowerdvp, 412 &lowervp, cnp); 413 if (um->um_op == UNMNT_BELOW) 414 cnp->cn_cred = saved_cred; 415 cnp->cn_nameiop = nameiop; 416 417 if (lowervp != lowerdvp) 418 VOP_UNLOCK(lowerdvp, 0); 419 420 if (cnp->cn_consume != 0) { 421 if (uppervp != NULLVP) { 422 if (uppervp == upperdvp) 423 vrele(uppervp); 424 else 425 vput(uppervp); 426 uppervp = NULLVP; 427 } 428 *ap->a_vpp = lowervp; 429 return (lerror); 430 } 431 } else { 432 lerror = ENOENT; 433 if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) { 434 lowervp = LOWERVP(dun->un_pvp); 435 if (lowervp != NULLVP) { 436 VREF(lowervp); 437 vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY); 438 lerror = 0; 439 } 440 } 441 } 442 443 /* 444 * EJUSTRETURN is used by underlying filesystems to indicate that 445 * a directory modification op was started successfully. 446 * This will only happen in the upper layer, since 447 * the lower layer only does LOOKUPs. 448 * If this union is mounted read-only, bounce it now. 449 */ 450 451 if ((uerror == EJUSTRETURN) && (cnp->cn_flags & ISLASTCN) && 452 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 453 ((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME))) 454 uerror = EROFS; 455 456 /* 457 * at this point, we have uerror and lerror indicating 458 * possible errors with the lookups in the upper and lower 459 * layers. additionally, uppervp and lowervp are (locked) 460 * references to existing vnodes in the upper and lower layers. 461 * 462 * there are now three cases to consider. 463 * 1. if both layers returned an error, then return whatever 464 * error the upper layer generated. 465 * 466 * 2. if the top layer failed and the bottom layer succeeded 467 * then two subcases occur. 468 * a. the bottom vnode is not a directory, in which 469 * case just return a new union vnode referencing 470 * an empty top layer and the existing bottom layer. 471 * b. the bottom vnode is a directory, in which case 472 * create a new directory in the top-level and 473 * continue as in case 3. 474 * 475 * 3. if the top layer succeeded then return a new union 476 * vnode referencing whatever the new top layer and 477 * whatever the bottom layer returned. 478 */ 479 480 *ap->a_vpp = NULLVP; 481 482 483 /* case 1. */ 484 if ((uerror != 0) && (lerror != 0)) { 485 return (uerror); 486 } 487 488 /* case 2. */ 489 if (uerror != 0 /* && (lerror == 0) */ ) { 490 if (lowervp->v_type == VDIR) { /* case 2b. */ 491 /* 492 * We may be racing another process to make the 493 * upper-level shadow directory. Be careful with 494 * locks/etc! 495 */ 496 if (upperdvp) { 497 dun->un_flags &= ~UN_ULOCK; 498 VOP_UNLOCK(upperdvp, 0); 499 uerror = union_mkshadow(um, upperdvp, cnp, 500 &uppervp); 501 vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY); 502 dun->un_flags |= UN_ULOCK; 503 } 504 if (uerror) { 505 if (lowervp != NULLVP) { 506 vput(lowervp); 507 lowervp = NULLVP; 508 } 509 return (uerror); 510 } 511 } 512 } 513 514 if (lowervp != NULLVP) 515 VOP_UNLOCK(lowervp, 0); 516 517 error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, 518 uppervp, lowervp, 1); 519 520 if (error) { 521 if (uppervp != NULLVP) 522 vput(uppervp); 523 if (lowervp != NULLVP) 524 vrele(lowervp); 525 } 526 527 return (error); 528 } 529 530 int 531 union_create(v) 532 void *v; 533 { 534 struct vop_create_args /* { 535 struct vnode *a_dvp; 536 struct vnode **a_vpp; 537 struct componentname *a_cnp; 538 struct vattr *a_vap; 539 } */ *ap = v; 540 struct union_node *un = VTOUNION(ap->a_dvp); 541 struct vnode *dvp = un->un_uppervp; 542 struct componentname *cnp = ap->a_cnp; 543 544 if (dvp != NULLVP) { 545 int error; 546 struct vnode *vp; 547 struct mount *mp; 548 549 FIXUP(un); 550 551 VREF(dvp); 552 un->un_flags |= UN_KLOCK; 553 mp = ap->a_dvp->v_mount; 554 vput(ap->a_dvp); 555 error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap); 556 if (error) 557 return (error); 558 559 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp, 560 NULLVP, 1); 561 if (error) 562 vput(vp); 563 return (error); 564 } 565 566 vput(ap->a_dvp); 567 return (EROFS); 568 } 569 570 int 571 union_whiteout(v) 572 void *v; 573 { 574 struct vop_whiteout_args /* { 575 struct vnode *a_dvp; 576 struct componentname *a_cnp; 577 int a_flags; 578 } */ *ap = v; 579 struct union_node *un = VTOUNION(ap->a_dvp); 580 struct componentname *cnp = ap->a_cnp; 581 582 if (un->un_uppervp == NULLVP) 583 return (EOPNOTSUPP); 584 585 FIXUP(un); 586 return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags)); 587 } 588 589 int 590 union_mknod(v) 591 void *v; 592 { 593 struct vop_mknod_args /* { 594 struct vnode *a_dvp; 595 struct vnode **a_vpp; 596 struct componentname *a_cnp; 597 struct vattr *a_vap; 598 } */ *ap = v; 599 struct union_node *un = VTOUNION(ap->a_dvp); 600 struct vnode *dvp = un->un_uppervp; 601 struct componentname *cnp = ap->a_cnp; 602 603 if (dvp != NULLVP) { 604 int error; 605 struct vnode *vp; 606 struct mount *mp; 607 608 FIXUP(un); 609 610 VREF(dvp); 611 un->un_flags |= UN_KLOCK; 612 mp = ap->a_dvp->v_mount; 613 vput(ap->a_dvp); 614 error = VOP_MKNOD(dvp, &vp, cnp, ap->a_vap); 615 if (error) 616 return (error); 617 618 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, 619 cnp, vp, NULLVP, 1); 620 if (error) 621 vput(vp); 622 return (error); 623 } 624 625 vput(ap->a_dvp); 626 return (EROFS); 627 } 628 629 int 630 union_open(v) 631 void *v; 632 { 633 struct vop_open_args /* { 634 struct vnodeop_desc *a_desc; 635 struct vnode *a_vp; 636 int a_mode; 637 kauth_cred_t a_cred; 638 } */ *ap = v; 639 struct union_node *un = VTOUNION(ap->a_vp); 640 struct vnode *tvp; 641 int mode = ap->a_mode; 642 kauth_cred_t cred = ap->a_cred; 643 struct lwp *l = curlwp; 644 int error; 645 646 /* 647 * If there is an existing upper vp then simply open that. 648 */ 649 tvp = un->un_uppervp; 650 if (tvp == NULLVP) { 651 /* 652 * If the lower vnode is being opened for writing, then 653 * copy the file contents to the upper vnode and open that, 654 * otherwise can simply open the lower vnode. 655 */ 656 tvp = un->un_lowervp; 657 if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) { 658 error = union_copyup(un, (mode&O_TRUNC) == 0, cred, l); 659 if (error == 0) 660 error = VOP_OPEN(un->un_uppervp, mode, cred); 661 return (error); 662 } 663 664 /* 665 * Just open the lower vnode, but check for nodev mount flag 666 */ 667 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 668 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 669 return ENXIO; 670 un->un_openl++; 671 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); 672 error = VOP_OPEN(tvp, mode, cred); 673 VOP_UNLOCK(tvp, 0); 674 675 return (error); 676 } 677 /* 678 * Just open the upper vnode, checking for nodev mount flag first 679 */ 680 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 681 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 682 return ENXIO; 683 684 FIXUP(un); 685 686 error = VOP_OPEN(tvp, mode, cred); 687 688 return (error); 689 } 690 691 int 692 union_close(v) 693 void *v; 694 { 695 struct vop_close_args /* { 696 struct vnode *a_vp; 697 int a_fflag; 698 kauth_cred_t a_cred; 699 } */ *ap = v; 700 struct union_node *un = VTOUNION(ap->a_vp); 701 struct vnode *vp; 702 703 vp = un->un_uppervp; 704 if (vp == NULLVP) { 705 #ifdef UNION_DIAGNOSTIC 706 if (un->un_openl <= 0) 707 panic("union: un_openl cnt"); 708 #endif 709 --un->un_openl; 710 vp = un->un_lowervp; 711 } 712 713 #ifdef DIAGNOSTIC 714 if (vp == NULLVP) 715 panic("union_close empty union vnode"); 716 #endif 717 718 ap->a_vp = vp; 719 return (VCALL(vp, VOFFSET(vop_close), ap)); 720 } 721 722 /* 723 * Check access permission on the union vnode. 724 * The access check being enforced is to check 725 * against both the underlying vnode, and any 726 * copied vnode. This ensures that no additional 727 * file permissions are given away simply because 728 * the user caused an implicit file copy. 729 */ 730 int 731 union_access(v) 732 void *v; 733 { 734 struct vop_access_args /* { 735 struct vnodeop_desc *a_desc; 736 struct vnode *a_vp; 737 int a_mode; 738 kauth_cred_t a_cred; 739 } */ *ap = v; 740 struct vnode *vp = ap->a_vp; 741 struct union_node *un = VTOUNION(vp); 742 int error = EACCES; 743 struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount); 744 745 /* 746 * Disallow write attempts on read-only file systems; 747 * unless the file is a socket, fifo, or a block or 748 * character device resident on the file system. 749 */ 750 if (ap->a_mode & VWRITE) { 751 switch (vp->v_type) { 752 case VDIR: 753 case VLNK: 754 case VREG: 755 if (vp->v_mount->mnt_flag & MNT_RDONLY) 756 return (EROFS); 757 break; 758 case VBAD: 759 case VBLK: 760 case VCHR: 761 case VSOCK: 762 case VFIFO: 763 case VNON: 764 default: 765 break; 766 } 767 } 768 769 770 if ((vp = un->un_uppervp) != NULLVP) { 771 FIXUP(un); 772 ap->a_vp = vp; 773 return (VCALL(vp, VOFFSET(vop_access), ap)); 774 } 775 776 if ((vp = un->un_lowervp) != NULLVP) { 777 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 778 ap->a_vp = vp; 779 error = VCALL(vp, VOFFSET(vop_access), ap); 780 if (error == 0) { 781 if (um->um_op == UNMNT_BELOW) { 782 ap->a_cred = um->um_cred; 783 error = VCALL(vp, VOFFSET(vop_access), ap); 784 } 785 } 786 VOP_UNLOCK(vp, 0); 787 if (error) 788 return (error); 789 } 790 791 return (error); 792 } 793 794 /* 795 * We handle getattr only to change the fsid and 796 * track object sizes 797 */ 798 int 799 union_getattr(v) 800 void *v; 801 { 802 struct vop_getattr_args /* { 803 struct vnode *a_vp; 804 struct vattr *a_vap; 805 kauth_cred_t a_cred; 806 } */ *ap = v; 807 int error; 808 struct union_node *un = VTOUNION(ap->a_vp); 809 struct vnode *vp = un->un_uppervp; 810 struct vattr *vap; 811 struct vattr va; 812 813 814 /* 815 * Some programs walk the filesystem hierarchy by counting 816 * links to directories to avoid stat'ing all the time. 817 * This means the link count on directories needs to be "correct". 818 * The only way to do that is to call getattr on both layers 819 * and fix up the link count. The link count will not necessarily 820 * be accurate but will be large enough to defeat the tree walkers. 821 * 822 * To make life more interesting, some filesystems don't keep 823 * track of link counts in the expected way, and return a 824 * link count of `1' for those directories; if either of the 825 * component directories returns a link count of `1', we return a 1. 826 */ 827 828 vap = ap->a_vap; 829 830 vp = un->un_uppervp; 831 if (vp != NULLVP) { 832 /* 833 * It's not clear whether VOP_GETATTR is to be 834 * called with the vnode locked or not. stat() calls 835 * it with (vp) locked, and fstat calls it with 836 * (vp) unlocked. 837 * In the mean time, compensate here by checking 838 * the union_node's lock flag. 839 */ 840 if (un->un_flags & UN_LOCKED) 841 FIXUP(un); 842 843 error = VOP_GETATTR(vp, vap, ap->a_cred); 844 if (error) 845 return (error); 846 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 847 } 848 849 if (vp == NULLVP) { 850 vp = un->un_lowervp; 851 } else if (vp->v_type == VDIR) { 852 vp = un->un_lowervp; 853 if (vp != NULLVP) 854 vap = &va; 855 } else { 856 vp = NULLVP; 857 } 858 859 if (vp != NULLVP) { 860 error = VOP_GETATTR(vp, vap, ap->a_cred); 861 if (error) 862 return (error); 863 union_newsize(ap->a_vp, VNOVAL, vap->va_size); 864 } 865 866 if ((vap != ap->a_vap) && (vap->va_type == VDIR)) { 867 /* 868 * Link count manipulation: 869 * - If both return "2", return 2 (no subdirs) 870 * - If one or the other return "1", return "1" (ENOCLUE) 871 */ 872 if ((ap->a_vap->va_nlink == 2) && 873 (vap->va_nlink == 2)) 874 ; 875 else if (ap->a_vap->va_nlink != 1) { 876 if (vap->va_nlink == 1) 877 ap->a_vap->va_nlink = 1; 878 else 879 ap->a_vap->va_nlink += vap->va_nlink; 880 } 881 } 882 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0]; 883 return (0); 884 } 885 886 int 887 union_setattr(v) 888 void *v; 889 { 890 struct vop_setattr_args /* { 891 struct vnode *a_vp; 892 struct vattr *a_vap; 893 kauth_cred_t a_cred; 894 } */ *ap = v; 895 struct vattr *vap = ap->a_vap; 896 struct vnode *vp = ap->a_vp; 897 struct union_node *un = VTOUNION(vp); 898 int error; 899 900 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL || 901 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL || 902 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) && 903 (vp->v_mount->mnt_flag & MNT_RDONLY)) 904 return (EROFS); 905 if (vap->va_size != VNOVAL) { 906 switch (vp->v_type) { 907 case VDIR: 908 return (EISDIR); 909 case VCHR: 910 case VBLK: 911 case VSOCK: 912 case VFIFO: 913 break; 914 case VREG: 915 case VLNK: 916 default: 917 /* 918 * Disallow write attempts if the filesystem is 919 * mounted read-only. 920 */ 921 if (vp->v_mount->mnt_flag & MNT_RDONLY) 922 return (EROFS); 923 } 924 } 925 926 /* 927 * Handle case of truncating lower object to zero size, 928 * by creating a zero length upper object. This is to 929 * handle the case of open with O_TRUNC and O_CREAT. 930 */ 931 if ((un->un_uppervp == NULLVP) && 932 /* assert(un->un_lowervp != NULLVP) */ 933 (un->un_lowervp->v_type == VREG)) { 934 error = union_copyup(un, (vap->va_size != 0), 935 ap->a_cred, curlwp); 936 if (error) 937 return (error); 938 } 939 940 /* 941 * Try to set attributes in upper layer, 942 * otherwise return read-only filesystem error. 943 */ 944 if (un->un_uppervp != NULLVP) { 945 FIXUP(un); 946 error = VOP_SETATTR(un->un_uppervp, vap, ap->a_cred); 947 if ((error == 0) && (vap->va_size != VNOVAL)) 948 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 949 } else { 950 error = EROFS; 951 } 952 953 return (error); 954 } 955 956 int 957 union_read(v) 958 void *v; 959 { 960 struct vop_read_args /* { 961 struct vnode *a_vp; 962 struct uio *a_uio; 963 int a_ioflag; 964 kauth_cred_t a_cred; 965 } */ *ap = v; 966 int error; 967 struct vnode *vp = OTHERVP(ap->a_vp); 968 int dolock = (vp == LOWERVP(ap->a_vp)); 969 970 if (dolock) 971 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 972 else 973 FIXUP(VTOUNION(ap->a_vp)); 974 error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 975 if (dolock) 976 VOP_UNLOCK(vp, 0); 977 978 /* 979 * XXX 980 * perhaps the size of the underlying object has changed under 981 * our feet. take advantage of the offset information present 982 * in the uio structure. 983 */ 984 if (error == 0) { 985 struct union_node *un = VTOUNION(ap->a_vp); 986 off_t cur = ap->a_uio->uio_offset; 987 988 if (vp == un->un_uppervp) { 989 if (cur > un->un_uppersz) 990 union_newsize(ap->a_vp, cur, VNOVAL); 991 } else { 992 if (cur > un->un_lowersz) 993 union_newsize(ap->a_vp, VNOVAL, cur); 994 } 995 } 996 997 return (error); 998 } 999 1000 int 1001 union_write(v) 1002 void *v; 1003 { 1004 struct vop_read_args /* { 1005 struct vnode *a_vp; 1006 struct uio *a_uio; 1007 int a_ioflag; 1008 kauth_cred_t a_cred; 1009 } */ *ap = v; 1010 int error; 1011 struct vnode *vp; 1012 struct union_node *un = VTOUNION(ap->a_vp); 1013 1014 vp = UPPERVP(ap->a_vp); 1015 if (vp == NULLVP) 1016 panic("union: missing upper layer in write"); 1017 1018 FIXUP(un); 1019 error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 1020 1021 /* 1022 * the size of the underlying object may be changed by the 1023 * write. 1024 */ 1025 if (error == 0) { 1026 off_t cur = ap->a_uio->uio_offset; 1027 1028 if (cur > un->un_uppersz) 1029 union_newsize(ap->a_vp, cur, VNOVAL); 1030 } 1031 1032 return (error); 1033 } 1034 1035 int 1036 union_lease(v) 1037 void *v; 1038 { 1039 struct vop_lease_args /* { 1040 struct vnode *a_vp; 1041 kauth_cred_t a_cred; 1042 int a_flag; 1043 } */ *ap = v; 1044 struct vnode *ovp = OTHERVP(ap->a_vp); 1045 1046 ap->a_vp = ovp; 1047 return (VCALL(ovp, VOFFSET(vop_lease), ap)); 1048 } 1049 1050 int 1051 union_ioctl(v) 1052 void *v; 1053 { 1054 struct vop_ioctl_args /* { 1055 struct vnode *a_vp; 1056 int a_command; 1057 void *a_data; 1058 int a_fflag; 1059 kauth_cred_t a_cred; 1060 } */ *ap = v; 1061 struct vnode *ovp = OTHERVP(ap->a_vp); 1062 1063 ap->a_vp = ovp; 1064 return (VCALL(ovp, VOFFSET(vop_ioctl), ap)); 1065 } 1066 1067 int 1068 union_poll(v) 1069 void *v; 1070 { 1071 struct vop_poll_args /* { 1072 struct vnode *a_vp; 1073 int a_events; 1074 } */ *ap = v; 1075 struct vnode *ovp = OTHERVP(ap->a_vp); 1076 1077 ap->a_vp = ovp; 1078 return (VCALL(ovp, VOFFSET(vop_poll), ap)); 1079 } 1080 1081 int 1082 union_revoke(v) 1083 void *v; 1084 { 1085 struct vop_revoke_args /* { 1086 struct vnode *a_vp; 1087 int a_flags; 1088 struct proc *a_p; 1089 } */ *ap = v; 1090 struct vnode *vp = ap->a_vp; 1091 1092 if (UPPERVP(vp)) 1093 VOP_REVOKE(UPPERVP(vp), ap->a_flags); 1094 if (LOWERVP(vp)) 1095 VOP_REVOKE(LOWERVP(vp), ap->a_flags); 1096 vgone(vp); 1097 return (0); 1098 } 1099 1100 int 1101 union_mmap(v) 1102 void *v; 1103 { 1104 struct vop_mmap_args /* { 1105 struct vnode *a_vp; 1106 vm_prot_t a_prot; 1107 kauth_cred_t a_cred; 1108 } */ *ap = v; 1109 struct vnode *ovp = OTHERVP(ap->a_vp); 1110 1111 ap->a_vp = ovp; 1112 return (VCALL(ovp, VOFFSET(vop_mmap), ap)); 1113 } 1114 1115 int 1116 union_fsync(v) 1117 void *v; 1118 { 1119 struct vop_fsync_args /* { 1120 struct vnode *a_vp; 1121 kauth_cred_t a_cred; 1122 int a_flags; 1123 off_t offhi; 1124 off_t offlo; 1125 } */ *ap = v; 1126 int error = 0; 1127 struct vnode *targetvp; 1128 1129 /* 1130 * If vinvalbuf is calling us, it's a "shallow fsync" -- don't 1131 * bother syncing the underlying vnodes, since (a) they'll be 1132 * fsync'ed when reclaimed and (b) we could deadlock if 1133 * they're locked; otherwise, pass it through to the 1134 * underlying layer. 1135 */ 1136 if (ap->a_flags & FSYNC_RECLAIM) 1137 return 0; 1138 1139 targetvp = OTHERVP(ap->a_vp); 1140 1141 if (targetvp != NULLVP) { 1142 int dolock = (targetvp == LOWERVP(ap->a_vp)); 1143 1144 if (dolock) 1145 vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY); 1146 else 1147 FIXUP(VTOUNION(ap->a_vp)); 1148 error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags, 1149 ap->a_offlo, ap->a_offhi); 1150 if (dolock) 1151 VOP_UNLOCK(targetvp, 0); 1152 } 1153 1154 return (error); 1155 } 1156 1157 int 1158 union_seek(v) 1159 void *v; 1160 { 1161 struct vop_seek_args /* { 1162 struct vnode *a_vp; 1163 off_t a_oldoff; 1164 off_t a_newoff; 1165 kauth_cred_t a_cred; 1166 } */ *ap = v; 1167 struct vnode *ovp = OTHERVP(ap->a_vp); 1168 1169 ap->a_vp = ovp; 1170 return (VCALL(ovp, VOFFSET(vop_seek), ap)); 1171 } 1172 1173 int 1174 union_remove(v) 1175 void *v; 1176 { 1177 struct vop_remove_args /* { 1178 struct vnode *a_dvp; 1179 struct vnode *a_vp; 1180 struct componentname *a_cnp; 1181 } */ *ap = v; 1182 int error; 1183 struct union_node *dun = VTOUNION(ap->a_dvp); 1184 struct union_node *un = VTOUNION(ap->a_vp); 1185 struct componentname *cnp = ap->a_cnp; 1186 1187 if (dun->un_uppervp == NULLVP) 1188 panic("union remove: null upper vnode"); 1189 1190 if (un->un_uppervp != NULLVP) { 1191 struct vnode *dvp = dun->un_uppervp; 1192 struct vnode *vp = un->un_uppervp; 1193 1194 FIXUP(dun); 1195 VREF(dvp); 1196 dun->un_flags |= UN_KLOCK; 1197 vput(ap->a_dvp); 1198 FIXUP(un); 1199 VREF(vp); 1200 un->un_flags |= UN_KLOCK; 1201 vput(ap->a_vp); 1202 1203 if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_lwp)) 1204 cnp->cn_flags |= DOWHITEOUT; 1205 error = VOP_REMOVE(dvp, vp, cnp); 1206 if (!error) 1207 union_removed_upper(un); 1208 } else { 1209 FIXUP(dun); 1210 error = union_mkwhiteout( 1211 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1212 dun->un_uppervp, ap->a_cnp, un->un_path); 1213 vput(ap->a_dvp); 1214 vput(ap->a_vp); 1215 } 1216 1217 return (error); 1218 } 1219 1220 int 1221 union_link(v) 1222 void *v; 1223 { 1224 struct vop_link_args /* { 1225 struct vnode *a_dvp; 1226 struct vnode *a_vp; 1227 struct componentname *a_cnp; 1228 } */ *ap = v; 1229 int error = 0; 1230 struct componentname *cnp = ap->a_cnp; 1231 struct lwp *l = cnp->cn_lwp; 1232 struct union_node *dun; 1233 struct vnode *vp; 1234 struct vnode *dvp; 1235 1236 dun = VTOUNION(ap->a_dvp); 1237 1238 #ifdef DIAGNOSTIC 1239 if (!(ap->a_cnp->cn_flags & LOCKPARENT)) { 1240 printf("union_link called without LOCKPARENT set!\n"); 1241 error = EIO; /* need some error code for "caller is a bozo" */ 1242 } else 1243 #endif 1244 1245 1246 if (ap->a_dvp->v_op != ap->a_vp->v_op) { 1247 vp = ap->a_vp; 1248 } else { 1249 struct union_node *un = VTOUNION(ap->a_vp); 1250 if (un->un_uppervp == NULLVP) { 1251 /* 1252 * Needs to be copied before we can link it. 1253 */ 1254 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY); 1255 if (dun->un_uppervp == un->un_dirvp) { 1256 dun->un_flags &= ~UN_ULOCK; 1257 VOP_UNLOCK(dun->un_uppervp, 0); 1258 } 1259 error = union_copyup(un, 1, cnp->cn_cred, l); 1260 if (dun->un_uppervp == un->un_dirvp) { 1261 /* 1262 * During copyup, we dropped the lock on the 1263 * dir and invalidated any saved namei lookup 1264 * state for the directory we'll be entering 1265 * the link in. We need to re-run the lookup 1266 * in that directory to reset any state needed 1267 * for VOP_LINK. 1268 * Call relookup on the union-layer to reset 1269 * the state. 1270 */ 1271 vp = NULLVP; 1272 if (dun->un_uppervp == NULLVP) 1273 panic("union: null upperdvp?"); 1274 error = relookup(ap->a_dvp, &vp, ap->a_cnp); 1275 if (error) { 1276 VOP_UNLOCK(ap->a_vp, 0); 1277 return EROFS; /* ? */ 1278 } 1279 if (vp != NULLVP) { 1280 /* 1281 * The name we want to create has 1282 * mysteriously appeared (a race?) 1283 */ 1284 error = EEXIST; 1285 VOP_UNLOCK(ap->a_vp, 0); 1286 vput(ap->a_dvp); 1287 vput(vp); 1288 return (error); 1289 } 1290 } 1291 VOP_UNLOCK(ap->a_vp, 0); 1292 } 1293 vp = un->un_uppervp; 1294 } 1295 1296 dvp = dun->un_uppervp; 1297 if (dvp == NULLVP) 1298 error = EROFS; 1299 1300 if (error) { 1301 vput(ap->a_dvp); 1302 return (error); 1303 } 1304 1305 FIXUP(dun); 1306 VREF(dvp); 1307 dun->un_flags |= UN_KLOCK; 1308 vput(ap->a_dvp); 1309 1310 return (VOP_LINK(dvp, vp, cnp)); 1311 } 1312 1313 int 1314 union_rename(v) 1315 void *v; 1316 { 1317 struct vop_rename_args /* { 1318 struct vnode *a_fdvp; 1319 struct vnode *a_fvp; 1320 struct componentname *a_fcnp; 1321 struct vnode *a_tdvp; 1322 struct vnode *a_tvp; 1323 struct componentname *a_tcnp; 1324 } */ *ap = v; 1325 int error; 1326 1327 struct vnode *fdvp = ap->a_fdvp; 1328 struct vnode *fvp = ap->a_fvp; 1329 struct vnode *tdvp = ap->a_tdvp; 1330 struct vnode *tvp = ap->a_tvp; 1331 1332 if (fdvp->v_op == union_vnodeop_p) { /* always true */ 1333 struct union_node *un = VTOUNION(fdvp); 1334 if (un->un_uppervp == NULLVP) { 1335 /* 1336 * this should never happen in normal 1337 * operation but might if there was 1338 * a problem creating the top-level shadow 1339 * directory. 1340 */ 1341 error = EXDEV; 1342 goto bad; 1343 } 1344 1345 fdvp = un->un_uppervp; 1346 VREF(fdvp); 1347 } 1348 1349 if (fvp->v_op == union_vnodeop_p) { /* always true */ 1350 struct union_node *un = VTOUNION(fvp); 1351 if (un->un_uppervp == NULLVP) { 1352 /* XXX: should do a copyup */ 1353 error = EXDEV; 1354 goto bad; 1355 } 1356 1357 if (un->un_lowervp != NULLVP) 1358 ap->a_fcnp->cn_flags |= DOWHITEOUT; 1359 1360 fvp = un->un_uppervp; 1361 VREF(fvp); 1362 } 1363 1364 if (tdvp->v_op == union_vnodeop_p) { 1365 struct union_node *un = VTOUNION(tdvp); 1366 if (un->un_uppervp == NULLVP) { 1367 /* 1368 * this should never happen in normal 1369 * operation but might if there was 1370 * a problem creating the top-level shadow 1371 * directory. 1372 */ 1373 error = EXDEV; 1374 goto bad; 1375 } 1376 1377 tdvp = un->un_uppervp; 1378 VREF(tdvp); 1379 un->un_flags |= UN_KLOCK; 1380 vput(ap->a_tdvp); 1381 } 1382 1383 if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) { 1384 struct union_node *un = VTOUNION(tvp); 1385 1386 tvp = un->un_uppervp; 1387 if (tvp != NULLVP) { 1388 VREF(tvp); 1389 un->un_flags |= UN_KLOCK; 1390 } 1391 vput(ap->a_tvp); 1392 } 1393 1394 error = VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp); 1395 goto out; 1396 1397 bad: 1398 vput(tdvp); 1399 if (tvp != NULLVP) 1400 vput(tvp); 1401 vrele(fdvp); 1402 vrele(fvp); 1403 1404 out: 1405 if (fdvp != ap->a_fdvp) { 1406 vrele(ap->a_fdvp); 1407 } 1408 if (fvp != ap->a_fvp) { 1409 vrele(ap->a_fvp); 1410 } 1411 return (error); 1412 } 1413 1414 int 1415 union_mkdir(v) 1416 void *v; 1417 { 1418 struct vop_mkdir_args /* { 1419 struct vnode *a_dvp; 1420 struct vnode **a_vpp; 1421 struct componentname *a_cnp; 1422 struct vattr *a_vap; 1423 } */ *ap = v; 1424 struct union_node *un = VTOUNION(ap->a_dvp); 1425 struct vnode *dvp = un->un_uppervp; 1426 struct componentname *cnp = ap->a_cnp; 1427 1428 if (dvp != NULLVP) { 1429 int error; 1430 struct vnode *vp; 1431 1432 FIXUP(un); 1433 VREF(dvp); 1434 un->un_flags |= UN_KLOCK; 1435 VOP_UNLOCK(ap->a_dvp, 0); 1436 error = VOP_MKDIR(dvp, &vp, cnp, ap->a_vap); 1437 if (error) { 1438 vrele(ap->a_dvp); 1439 return (error); 1440 } 1441 1442 error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, 1443 NULLVP, cnp, vp, NULLVP, 1); 1444 if (error) 1445 vput(vp); 1446 vrele(ap->a_dvp); 1447 return (error); 1448 } 1449 1450 vput(ap->a_dvp); 1451 return (EROFS); 1452 } 1453 1454 int 1455 union_rmdir(v) 1456 void *v; 1457 { 1458 struct vop_rmdir_args /* { 1459 struct vnode *a_dvp; 1460 struct vnode *a_vp; 1461 struct componentname *a_cnp; 1462 } */ *ap = v; 1463 int error; 1464 struct union_node *dun = VTOUNION(ap->a_dvp); 1465 struct union_node *un = VTOUNION(ap->a_vp); 1466 struct componentname *cnp = ap->a_cnp; 1467 1468 if (dun->un_uppervp == NULLVP) 1469 panic("union rmdir: null upper vnode"); 1470 1471 if (un->un_uppervp != NULLVP) { 1472 struct vnode *dvp = dun->un_uppervp; 1473 struct vnode *vp = un->un_uppervp; 1474 1475 FIXUP(dun); 1476 VREF(dvp); 1477 dun->un_flags |= UN_KLOCK; 1478 vput(ap->a_dvp); 1479 FIXUP(un); 1480 VREF(vp); 1481 un->un_flags |= UN_KLOCK; 1482 vput(ap->a_vp); 1483 1484 if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_lwp)) 1485 cnp->cn_flags |= DOWHITEOUT; 1486 error = VOP_RMDIR(dvp, vp, ap->a_cnp); 1487 if (!error) 1488 union_removed_upper(un); 1489 } else { 1490 FIXUP(dun); 1491 error = union_mkwhiteout( 1492 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1493 dun->un_uppervp, ap->a_cnp, un->un_path); 1494 vput(ap->a_dvp); 1495 vput(ap->a_vp); 1496 } 1497 1498 return (error); 1499 } 1500 1501 int 1502 union_symlink(v) 1503 void *v; 1504 { 1505 struct vop_symlink_args /* { 1506 struct vnode *a_dvp; 1507 struct vnode **a_vpp; 1508 struct componentname *a_cnp; 1509 struct vattr *a_vap; 1510 char *a_target; 1511 } */ *ap = v; 1512 struct union_node *un = VTOUNION(ap->a_dvp); 1513 struct vnode *dvp = un->un_uppervp; 1514 struct componentname *cnp = ap->a_cnp; 1515 1516 if (dvp != NULLVP) { 1517 int error; 1518 1519 FIXUP(un); 1520 VREF(dvp); 1521 un->un_flags |= UN_KLOCK; 1522 vput(ap->a_dvp); 1523 error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap, 1524 ap->a_target); 1525 return (error); 1526 } 1527 1528 vput(ap->a_dvp); 1529 return (EROFS); 1530 } 1531 1532 /* 1533 * union_readdir works in concert with getdirentries and 1534 * readdir(3) to provide a list of entries in the unioned 1535 * directories. getdirentries is responsible for walking 1536 * down the union stack. readdir(3) is responsible for 1537 * eliminating duplicate names from the returned data stream. 1538 */ 1539 int 1540 union_readdir(v) 1541 void *v; 1542 { 1543 struct vop_readdir_args /* { 1544 struct vnodeop_desc *a_desc; 1545 struct vnode *a_vp; 1546 struct uio *a_uio; 1547 kauth_cred_t a_cred; 1548 int *a_eofflag; 1549 u_long *a_cookies; 1550 int a_ncookies; 1551 } */ *ap = v; 1552 struct union_node *un = VTOUNION(ap->a_vp); 1553 struct vnode *uvp = un->un_uppervp; 1554 1555 if (uvp == NULLVP) 1556 return (0); 1557 1558 FIXUP(un); 1559 ap->a_vp = uvp; 1560 return (VCALL(uvp, VOFFSET(vop_readdir), ap)); 1561 } 1562 1563 int 1564 union_readlink(v) 1565 void *v; 1566 { 1567 struct vop_readlink_args /* { 1568 struct vnode *a_vp; 1569 struct uio *a_uio; 1570 kauth_cred_t a_cred; 1571 } */ *ap = v; 1572 int error; 1573 struct vnode *vp = OTHERVP(ap->a_vp); 1574 int dolock = (vp == LOWERVP(ap->a_vp)); 1575 1576 if (dolock) 1577 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1578 else 1579 FIXUP(VTOUNION(ap->a_vp)); 1580 ap->a_vp = vp; 1581 error = VCALL(vp, VOFFSET(vop_readlink), ap); 1582 if (dolock) 1583 VOP_UNLOCK(vp, 0); 1584 1585 return (error); 1586 } 1587 1588 int 1589 union_abortop(v) 1590 void *v; 1591 { 1592 struct vop_abortop_args /* { 1593 struct vnode *a_dvp; 1594 struct componentname *a_cnp; 1595 } */ *ap = v; 1596 int error; 1597 struct vnode *vp = OTHERVP(ap->a_dvp); 1598 struct union_node *un = VTOUNION(ap->a_dvp); 1599 int islocked = un->un_flags & UN_LOCKED; 1600 int dolock = (vp == LOWERVP(ap->a_dvp)); 1601 1602 if (islocked) { 1603 if (dolock) 1604 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1605 else 1606 FIXUP(VTOUNION(ap->a_dvp)); 1607 } 1608 ap->a_dvp = vp; 1609 error = VCALL(vp, VOFFSET(vop_abortop), ap); 1610 if (islocked && dolock) 1611 VOP_UNLOCK(vp, 0); 1612 1613 return (error); 1614 } 1615 1616 int 1617 union_inactive(v) 1618 void *v; 1619 { 1620 struct vop_inactive_args /* { 1621 const struct vnodeop_desc *a_desc; 1622 struct vnode *a_vp; 1623 } */ *ap = v; 1624 struct vnode *vp = ap->a_vp; 1625 struct union_node *un = VTOUNION(vp); 1626 struct vnode **vpp; 1627 1628 /* 1629 * Do nothing (and _don't_ bypass). 1630 * Wait to vrele lowervp until reclaim, 1631 * so that until then our union_node is in the 1632 * cache and reusable. 1633 * 1634 * NEEDSWORK: Someday, consider inactive'ing 1635 * the lowervp and then trying to reactivate it 1636 * with capabilities (v_id) 1637 * like they do in the name lookup cache code. 1638 * That's too much work for now. 1639 */ 1640 1641 if (un->un_dircache != 0) { 1642 for (vpp = un->un_dircache; *vpp != NULLVP; vpp++) 1643 vrele(*vpp); 1644 free(un->un_dircache, M_TEMP); 1645 un->un_dircache = 0; 1646 } 1647 1648 VOP_UNLOCK(vp, 0); 1649 1650 if ((un->un_flags & UN_CACHED) == 0) 1651 vgone(vp); 1652 1653 return (0); 1654 } 1655 1656 int 1657 union_reclaim(v) 1658 void *v; 1659 { 1660 struct vop_reclaim_args /* { 1661 struct vnode *a_vp; 1662 } */ *ap = v; 1663 1664 union_freevp(ap->a_vp); 1665 1666 return (0); 1667 } 1668 1669 int 1670 union_lock(v) 1671 void *v; 1672 { 1673 struct vop_lock_args /* { 1674 struct vnode *a_vp; 1675 int a_flags; 1676 } */ *ap = v; 1677 struct vnode *vp = ap->a_vp; 1678 int flags = ap->a_flags; 1679 struct union_node *un; 1680 int error; 1681 #ifdef DIAGNOSTIC 1682 int drain = 0; 1683 #endif 1684 1685 /* XXX unionfs can't handle shared locks yet */ 1686 if ((flags & LK_TYPE_MASK) == LK_SHARED) { 1687 flags = LK_EXCLUSIVE | (flags & ~LK_TYPE_MASK); 1688 } 1689 1690 genfs_nolock(ap); 1691 /* 1692 * Need to do real lockmgr-style locking here. 1693 * in the mean time, draining won't work quite right, 1694 * which could lead to a few race conditions. 1695 * the following test was here, but is not quite right, we 1696 * still need to take the lock: 1697 if ((flags & LK_TYPE_MASK) == LK_DRAIN) 1698 return (0); 1699 */ 1700 flags &= ~LK_INTERLOCK; 1701 1702 un = VTOUNION(vp); 1703 #ifdef DIAGNOSTIC 1704 if (un->un_flags & (UN_DRAINING|UN_DRAINED)) { 1705 if (un->un_flags & UN_DRAINED) 1706 panic("union: %p: warning: locking decommissioned lock", vp); 1707 if ((flags & LK_TYPE_MASK) != LK_RELEASE) 1708 panic("union: %p: non-release on draining lock: %d", 1709 vp, flags & LK_TYPE_MASK); 1710 un->un_flags &= ~UN_DRAINING; 1711 if ((flags & LK_REENABLE) == 0) 1712 un->un_flags |= UN_DRAINED; 1713 } 1714 #endif 1715 1716 /* 1717 * Don't pass DRAIN through to sub-vnode lock; keep track of 1718 * DRAIN state at this level, and just get an exclusive lock 1719 * on the underlying vnode. 1720 */ 1721 if ((flags & LK_TYPE_MASK) == LK_DRAIN) { 1722 #ifdef DIAGNOSTIC 1723 drain = 1; 1724 #endif 1725 flags = LK_EXCLUSIVE | (flags & ~LK_TYPE_MASK); 1726 } 1727 start: 1728 un = VTOUNION(vp); 1729 1730 if (un->un_uppervp != NULLVP) { 1731 if (((un->un_flags & UN_ULOCK) == 0) && 1732 (vp->v_usecount != 0)) { 1733 /* 1734 * We MUST always use the order of: take upper 1735 * vp lock, manipulate union node flags, drop 1736 * upper vp lock. This code must not be an 1737 */ 1738 error = vn_lock(un->un_uppervp, flags); 1739 if (error) 1740 return (error); 1741 un->un_flags |= UN_ULOCK; 1742 } 1743 #ifdef DIAGNOSTIC 1744 if (un->un_flags & UN_KLOCK) { 1745 vprint("union: dangling klock", vp); 1746 panic("union: dangling upper lock (%p)", vp); 1747 } 1748 #endif 1749 } 1750 1751 /* XXX ignores LK_NOWAIT */ 1752 if (un->un_flags & UN_LOCKED) { 1753 #ifdef DIAGNOSTIC 1754 if (curproc && un->un_pid == curproc->p_pid && 1755 un->un_pid > -1 && curproc->p_pid > -1) 1756 panic("union: locking against myself"); 1757 #endif 1758 un->un_flags |= UN_WANTED; 1759 tsleep(&un->un_flags, PINOD, "unionlk2", 0); 1760 goto start; 1761 } 1762 1763 #ifdef DIAGNOSTIC 1764 if (curproc) 1765 un->un_pid = curproc->p_pid; 1766 else 1767 un->un_pid = -1; 1768 if (drain) 1769 un->un_flags |= UN_DRAINING; 1770 #endif 1771 1772 un->un_flags |= UN_LOCKED; 1773 return (0); 1774 } 1775 1776 /* 1777 * When operations want to vput() a union node yet retain a lock on 1778 * the upper vnode (say, to do some further operations like link(), 1779 * mkdir(), ...), they set UN_KLOCK on the union node, then call 1780 * vput() which calls VOP_UNLOCK() and comes here. union_unlock() 1781 * unlocks the union node (leaving the upper vnode alone), clears the 1782 * KLOCK flag, and then returns to vput(). The caller then does whatever 1783 * is left to do with the upper vnode, and ensures that it gets unlocked. 1784 * 1785 * If UN_KLOCK isn't set, then the upper vnode is unlocked here. 1786 */ 1787 int 1788 union_unlock(v) 1789 void *v; 1790 { 1791 struct vop_unlock_args /* { 1792 struct vnode *a_vp; 1793 int a_flags; 1794 } */ *ap = v; 1795 struct union_node *un = VTOUNION(ap->a_vp); 1796 1797 #ifdef DIAGNOSTIC 1798 if ((un->un_flags & UN_LOCKED) == 0) 1799 panic("union: unlock unlocked node"); 1800 if (curproc && un->un_pid != curproc->p_pid && 1801 curproc->p_pid > -1 && un->un_pid > -1) 1802 panic("union: unlocking other process's union node"); 1803 if (un->un_flags & UN_DRAINED) 1804 panic("union: %p: warning: unlocking decommissioned lock", ap->a_vp); 1805 #endif 1806 1807 un->un_flags &= ~UN_LOCKED; 1808 1809 if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK) 1810 VOP_UNLOCK(un->un_uppervp, 0); 1811 1812 un->un_flags &= ~(UN_ULOCK|UN_KLOCK); 1813 1814 if (un->un_flags & UN_WANTED) { 1815 un->un_flags &= ~UN_WANTED; 1816 wakeup( &un->un_flags); 1817 } 1818 1819 #ifdef DIAGNOSTIC 1820 un->un_pid = 0; 1821 if (un->un_flags & UN_DRAINING) { 1822 un->un_flags |= UN_DRAINED; 1823 un->un_flags &= ~UN_DRAINING; 1824 } 1825 #endif 1826 genfs_nounlock(ap); 1827 1828 return (0); 1829 } 1830 1831 int 1832 union_bmap(v) 1833 void *v; 1834 { 1835 struct vop_bmap_args /* { 1836 struct vnode *a_vp; 1837 daddr_t a_bn; 1838 struct vnode **a_vpp; 1839 daddr_t *a_bnp; 1840 int *a_runp; 1841 } */ *ap = v; 1842 int error; 1843 struct vnode *vp = OTHERVP(ap->a_vp); 1844 int dolock = (vp == LOWERVP(ap->a_vp)); 1845 1846 if (dolock) 1847 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1848 else 1849 FIXUP(VTOUNION(ap->a_vp)); 1850 ap->a_vp = vp; 1851 error = VCALL(vp, VOFFSET(vop_bmap), ap); 1852 if (dolock) 1853 VOP_UNLOCK(vp, 0); 1854 1855 return (error); 1856 } 1857 1858 int 1859 union_print(v) 1860 void *v; 1861 { 1862 struct vop_print_args /* { 1863 struct vnode *a_vp; 1864 } */ *ap = v; 1865 struct vnode *vp = ap->a_vp; 1866 1867 printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n", 1868 vp, UPPERVP(vp), LOWERVP(vp)); 1869 if (UPPERVP(vp) != NULLVP) 1870 vprint("union: upper", UPPERVP(vp)); 1871 if (LOWERVP(vp) != NULLVP) 1872 vprint("union: lower", LOWERVP(vp)); 1873 if (VTOUNION(vp)->un_dircache) { 1874 struct vnode **vpp; 1875 for (vpp = VTOUNION(vp)->un_dircache; *vpp != NULLVP; vpp++) 1876 vprint("dircache:", *vpp); 1877 } 1878 1879 return (0); 1880 } 1881 1882 int 1883 union_islocked(v) 1884 void *v; 1885 { 1886 struct vop_islocked_args /* { 1887 struct vnode *a_vp; 1888 } */ *ap = v; 1889 1890 return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0); 1891 } 1892 1893 int 1894 union_pathconf(v) 1895 void *v; 1896 { 1897 struct vop_pathconf_args /* { 1898 struct vnode *a_vp; 1899 int a_name; 1900 int *a_retval; 1901 } */ *ap = v; 1902 int error; 1903 struct vnode *vp = OTHERVP(ap->a_vp); 1904 int dolock = (vp == LOWERVP(ap->a_vp)); 1905 1906 if (dolock) 1907 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1908 else 1909 FIXUP(VTOUNION(ap->a_vp)); 1910 ap->a_vp = vp; 1911 error = VCALL(vp, VOFFSET(vop_pathconf), ap); 1912 if (dolock) 1913 VOP_UNLOCK(vp, 0); 1914 1915 return (error); 1916 } 1917 1918 int 1919 union_advlock(v) 1920 void *v; 1921 { 1922 struct vop_advlock_args /* { 1923 struct vnode *a_vp; 1924 void *a_id; 1925 int a_op; 1926 struct flock *a_fl; 1927 int a_flags; 1928 } */ *ap = v; 1929 struct vnode *ovp = OTHERVP(ap->a_vp); 1930 1931 ap->a_vp = ovp; 1932 return (VCALL(ovp, VOFFSET(vop_advlock), ap)); 1933 } 1934 1935 1936 /* 1937 * XXX - vop_strategy must be hand coded because it has no 1938 * vnode in its arguments. 1939 * This goes away with a merged VM/buffer cache. 1940 */ 1941 int 1942 union_strategy(v) 1943 void *v; 1944 { 1945 struct vop_strategy_args /* { 1946 struct vnode *a_vp; 1947 struct buf *a_bp; 1948 } */ *ap = v; 1949 struct vnode *ovp = OTHERVP(ap->a_vp); 1950 struct buf *bp = ap->a_bp; 1951 1952 #ifdef DIAGNOSTIC 1953 if (ovp == NULLVP) 1954 panic("union_strategy: nil vp"); 1955 if (((bp->b_flags & B_READ) == 0) && 1956 (ovp == LOWERVP(bp->b_vp))) 1957 panic("union_strategy: writing to lowervp"); 1958 #endif 1959 1960 return (VOP_STRATEGY(ovp, bp)); 1961 } 1962 1963 int 1964 union_getpages(v) 1965 void *v; 1966 { 1967 struct vop_getpages_args /* { 1968 struct vnode *a_vp; 1969 voff_t a_offset; 1970 struct vm_page **a_m; 1971 int *a_count; 1972 int a_centeridx; 1973 vm_prot_t a_access_type; 1974 int a_advice; 1975 int a_flags; 1976 } */ *ap = v; 1977 struct vnode *vp = ap->a_vp; 1978 int error; 1979 1980 /* 1981 * just pass the request on to the underlying layer. 1982 */ 1983 1984 if (ap->a_flags & PGO_LOCKED) { 1985 return EBUSY; 1986 } 1987 ap->a_vp = OTHERVP(vp); 1988 simple_unlock(&vp->v_interlock); 1989 simple_lock(&ap->a_vp->v_interlock); 1990 error = VCALL(ap->a_vp, VOFFSET(vop_getpages), ap); 1991 return error; 1992 } 1993 1994 int 1995 union_putpages(v) 1996 void *v; 1997 { 1998 struct vop_putpages_args /* { 1999 struct vnode *a_vp; 2000 voff_t a_offlo; 2001 voff_t a_offhi; 2002 int a_flags; 2003 } */ *ap = v; 2004 struct vnode *vp = ap->a_vp; 2005 int error; 2006 2007 /* 2008 * just pass the request on to the underlying layer. 2009 */ 2010 2011 ap->a_vp = OTHERVP(vp); 2012 simple_unlock(&vp->v_interlock); 2013 if (ap->a_flags & PGO_RECLAIM) { 2014 return 0; 2015 } 2016 simple_lock(&ap->a_vp->v_interlock); 2017 error = VCALL(ap->a_vp, VOFFSET(vop_putpages), ap); 2018 return error; 2019 } 2020 2021 int 2022 union_kqfilter(void *v) 2023 { 2024 struct vop_kqfilter_args /* { 2025 struct vnode *a_vp; 2026 struct knote *a_kn; 2027 } */ *ap = v; 2028 int error; 2029 2030 /* 2031 * We watch either the upper layer file (if it already exists), 2032 * or the lower layer one. If there is lower layer file only 2033 * at this moment, we will keep watching that lower layer file 2034 * even if upper layer file would be created later on. 2035 */ 2036 if (UPPERVP(ap->a_vp)) 2037 error = VOP_KQFILTER(UPPERVP(ap->a_vp), ap->a_kn); 2038 else if (LOWERVP(ap->a_vp)) 2039 error = VOP_KQFILTER(LOWERVP(ap->a_vp), ap->a_kn); 2040 else { 2041 /* panic? */ 2042 error = EOPNOTSUPP; 2043 } 2044 2045 return (error); 2046 } 2047
Indexes created Mon Sep 29 21:09:56 GMT 2025