union_vnops.c revision 1.4
1/* $NetBSD: union_vnops.c,v 1.4 2003/06/29 15:11:48 thorpej Exp $ */ 2 3/* 4 * Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry. 5 * Copyright (c) 1992, 1993, 1994, 1995 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Jan-Simon Pendry. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)union_vnops.c 8.33 (Berkeley) 7/31/95 40 */ 41 42#include <sys/cdefs.h> 43__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.4 2003/06/29 15:11:48 thorpej Exp $"); 44 45#include <sys/param.h> 46#include <sys/systm.h> 47#include <sys/proc.h> 48#include <sys/file.h> 49#include <sys/time.h> 50#include <sys/stat.h> 51#include <sys/vnode.h> 52#include <sys/mount.h> 53#include <sys/namei.h> 54#include <sys/malloc.h> 55#include <sys/buf.h> 56#include <sys/queue.h> 57#include <sys/lock.h> 58#include <fs/union/union.h> 59#include <miscfs/genfs/genfs.h> 60 61int union_lookup __P((void *)); 62int union_create __P((void *)); 63int union_whiteout __P((void *)); 64int union_mknod __P((void *)); 65int union_open __P((void *)); 66int union_close __P((void *)); 67int union_access __P((void *)); 68int union_getattr __P((void *)); 69int union_setattr __P((void *)); 70int union_read __P((void *)); 71int union_write __P((void *)); 72int union_lease __P((void *)); 73int union_ioctl __P((void *)); 74int union_poll __P((void *)); 75int union_revoke __P((void *)); 76int union_mmap __P((void *)); 77int union_fsync __P((void *)); 78int union_seek __P((void *)); 79int union_remove __P((void *)); 80int union_link __P((void *)); 81int union_rename __P((void *)); 82int union_mkdir __P((void *)); 83int union_rmdir __P((void *)); 84int union_symlink __P((void *)); 85int union_readdir __P((void *)); 86int union_readlink __P((void *)); 87int union_abortop __P((void *)); 88int union_inactive __P((void *)); 89int union_reclaim __P((void *)); 90int union_lock __P((void *)); 91int union_unlock __P((void *)); 92int union_bmap __P((void *)); 93int union_print __P((void *)); 94int union_islocked __P((void *)); 95int union_pathconf __P((void *)); 96int union_advlock __P((void *)); 97int union_strategy __P((void *)); 98int union_getpages __P((void *)); 99int union_putpages __P((void *)); 100int union_kqfilter __P((void *)); 101 102static void union_fixup __P((struct union_node *)); 103static int union_lookup1 __P((struct vnode *, struct vnode **, 104 struct vnode **, struct componentname *)); 105 106 107/* 108 * Global vfs data structures 109 */ 110int (**union_vnodeop_p) __P((void *)); 111const struct vnodeopv_entry_desc union_vnodeop_entries[] = { 112 { &vop_default_desc, vn_default_error }, 113 { &vop_lookup_desc, union_lookup }, /* lookup */ 114 { &vop_create_desc, union_create }, /* create */ 115 { &vop_whiteout_desc, union_whiteout }, /* whiteout */ 116 { &vop_mknod_desc, union_mknod }, /* mknod */ 117 { &vop_open_desc, union_open }, /* open */ 118 { &vop_close_desc, union_close }, /* close */ 119 { &vop_access_desc, union_access }, /* access */ 120 { &vop_getattr_desc, union_getattr }, /* getattr */ 121 { &vop_setattr_desc, union_setattr }, /* setattr */ 122 { &vop_read_desc, union_read }, /* read */ 123 { &vop_write_desc, union_write }, /* write */ 124 { &vop_lease_desc, union_lease }, /* lease */ 125 { &vop_ioctl_desc, union_ioctl }, /* ioctl */ 126 { &vop_poll_desc, union_poll }, /* select */ 127 { &vop_revoke_desc, union_revoke }, /* revoke */ 128 { &vop_mmap_desc, union_mmap }, /* mmap */ 129 { &vop_fsync_desc, union_fsync }, /* fsync */ 130 { &vop_seek_desc, union_seek }, /* seek */ 131 { &vop_remove_desc, union_remove }, /* remove */ 132 { &vop_link_desc, union_link }, /* link */ 133 { &vop_rename_desc, union_rename }, /* rename */ 134 { &vop_mkdir_desc, union_mkdir }, /* mkdir */ 135 { &vop_rmdir_desc, union_rmdir }, /* rmdir */ 136 { &vop_symlink_desc, union_symlink }, /* symlink */ 137 { &vop_readdir_desc, union_readdir }, /* readdir */ 138 { &vop_readlink_desc, union_readlink }, /* readlink */ 139 { &vop_abortop_desc, union_abortop }, /* abortop */ 140 { &vop_inactive_desc, union_inactive }, /* inactive */ 141 { &vop_reclaim_desc, union_reclaim }, /* reclaim */ 142 { &vop_lock_desc, union_lock }, /* lock */ 143 { &vop_unlock_desc, union_unlock }, /* unlock */ 144 { &vop_bmap_desc, union_bmap }, /* bmap */ 145 { &vop_strategy_desc, union_strategy }, /* strategy */ 146 { &vop_print_desc, union_print }, /* print */ 147 { &vop_islocked_desc, union_islocked }, /* islocked */ 148 { &vop_pathconf_desc, union_pathconf }, /* pathconf */ 149 { &vop_advlock_desc, union_advlock }, /* advlock */ 150 { &vop_getpages_desc, union_getpages }, /* getpages */ 151 { &vop_putpages_desc, union_putpages }, /* putpages */ 152 { &vop_kqfilter_desc, union_kqfilter }, /* kqfilter */ 153#ifdef notdef 154 { &vop_blkatoff_desc, union_blkatoff }, /* blkatoff */ 155 { &vop_valloc_desc, union_valloc }, /* valloc */ 156 { &vop_vfree_desc, union_vfree }, /* vfree */ 157 { &vop_truncate_desc, union_truncate }, /* truncate */ 158 { &vop_update_desc, union_update }, /* update */ 159 { &vop_bwrite_desc, union_bwrite }, /* bwrite */ 160#endif 161 { NULL, NULL } 162}; 163const struct vnodeopv_desc union_vnodeop_opv_desc = 164 { &union_vnodeop_p, union_vnodeop_entries }; 165 166#define FIXUP(un) { \ 167 if (((un)->un_flags & UN_ULOCK) == 0) { \ 168 union_fixup(un); \ 169 } \ 170} 171 172static void 173union_fixup(un) 174 struct union_node *un; 175{ 176 177 vn_lock(un->un_uppervp, LK_EXCLUSIVE | LK_RETRY); 178 un->un_flags |= UN_ULOCK; 179} 180 181static int 182union_lookup1(udvp, dvpp, vpp, cnp) 183 struct vnode *udvp; 184 struct vnode **dvpp; 185 struct vnode **vpp; 186 struct componentname *cnp; 187{ 188 int error; 189 struct vnode *tdvp; 190 struct vnode *dvp; 191 struct mount *mp; 192 193 dvp = *dvpp; 194 195 /* 196 * If stepping up the directory tree, check for going 197 * back across the mount point, in which case do what 198 * lookup would do by stepping back down the mount 199 * hierarchy. 200 */ 201 if (cnp->cn_flags & ISDOTDOT) { 202 while ((dvp != udvp) && (dvp->v_flag & VROOT)) { 203 /* 204 * Don't do the NOCROSSMOUNT check 205 * at this level. By definition, 206 * union fs deals with namespaces, not 207 * filesystems. 208 */ 209 tdvp = dvp; 210 *dvpp = dvp = dvp->v_mount->mnt_vnodecovered; 211 vput(tdvp); 212 VREF(dvp); 213 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 214 } 215 } 216 217 error = VOP_LOOKUP(dvp, &tdvp, cnp); 218 if (error) 219 return (error); 220 221 /* 222 * The parent directory will have been unlocked, unless lookup 223 * found the last component. In which case, re-lock the node 224 * here to allow it to be unlocked again (phew) in union_lookup. 225 */ 226 if (dvp != tdvp && !(cnp->cn_flags & ISLASTCN)) 227 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 228 229 dvp = tdvp; 230 231 /* 232 * Lastly check if the current node is a mount point in 233 * which case walk up the mount hierarchy making sure not to 234 * bump into the root of the mount tree (ie. dvp != udvp). 235 */ 236 while (dvp != udvp && (dvp->v_type == VDIR) && 237 (mp = dvp->v_mountedhere)) { 238 239 if (vfs_busy(mp, 0, 0)) 240 continue; 241 242 error = VFS_ROOT(mp, &tdvp, cnp->cn_lwp); 243 vfs_unbusy(mp); 244 if (error) { 245 vput(dvp); 246 return (error); 247 } 248 249 vput(dvp); 250 dvp = tdvp; 251 } 252 253 *vpp = dvp; 254 return (0); 255} 256 257int 258union_lookup(v) 259 void *v; 260{ 261 struct vop_lookup_args /* { 262 struct vnodeop_desc *a_desc; 263 struct vnode *a_dvp; 264 struct vnode **a_vpp; 265 struct componentname *a_cnp; 266 } */ *ap = v; 267 int error; 268 int uerror, lerror; 269 struct vnode *uppervp, *lowervp; 270 struct vnode *upperdvp, *lowerdvp; 271 struct vnode *dvp = ap->a_dvp; 272 struct union_node *dun = VTOUNION(dvp); 273 struct componentname *cnp = ap->a_cnp; 274 int lockparent = cnp->cn_flags & LOCKPARENT; 275 struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); 276 struct ucred *saved_cred = NULL; 277 int iswhiteout; 278 struct vattr va; 279 280#ifdef notyet 281 if (cnp->cn_namelen == 3 && 282 cnp->cn_nameptr[2] == '.' && 283 cnp->cn_nameptr[1] == '.' && 284 cnp->cn_nameptr[0] == '.') { 285 dvp = *ap->a_vpp = LOWERVP(ap->a_dvp); 286 if (dvp == NULLVP) 287 return (ENOENT); 288 VREF(dvp); 289 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 290 if (!lockparent || !(cnp->cn_flags & ISLASTCN)) 291 VOP_UNLOCK(ap->a_dvp, 0); 292 return (0); 293 } 294#endif 295 296 if ((cnp->cn_flags & ISLASTCN) && 297 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 298 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 299 return (EROFS); 300 301 cnp->cn_flags |= LOCKPARENT; 302 303 upperdvp = dun->un_uppervp; 304 lowerdvp = dun->un_lowervp; 305 uppervp = NULLVP; 306 lowervp = NULLVP; 307 iswhiteout = 0; 308 309 /* 310 * do the lookup in the upper level. 311 * if that level comsumes additional pathnames, 312 * then assume that something special is going 313 * on and just return that vnode. 314 */ 315 if (upperdvp != NULLVP) { 316 FIXUP(dun); 317 /* 318 * If we're doing `..' in the underlying filesystem, 319 * we must drop our lock on the union node before 320 * going up the tree in the lower file system--if we block 321 * on the lowervp lock, and that's held by someone else 322 * coming down the tree and who's waiting for our lock, 323 * we would be hosed. 324 */ 325 if (cnp->cn_flags & ISDOTDOT) { 326 /* retain lock on underlying VP */ 327 dun->un_flags |= UN_KLOCK; 328 VOP_UNLOCK(dvp, 0); 329 } 330 uerror = union_lookup1(um->um_uppervp, &upperdvp, 331 &uppervp, cnp); 332 333 if (cnp->cn_flags & ISDOTDOT) { 334 if (dun->un_uppervp == upperdvp) { 335 /* 336 * we got the underlying bugger back locked... 337 * now take back the union node lock. Since we 338 * hold the uppervp lock, we can diddle union 339 * locking flags at will. :) 340 */ 341 dun->un_flags |= UN_ULOCK; 342 } 343 /* 344 * if upperdvp got swapped out, it means we did 345 * some mount point magic, and we do not have 346 * dun->un_uppervp locked currently--so we get it 347 * locked here (don't set the UN_ULOCK flag). 348 */ 349 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 350 } 351 if (cnp->cn_consume != 0) { 352 *ap->a_vpp = uppervp; 353 if (!lockparent) 354 cnp->cn_flags &= ~LOCKPARENT; 355 return (uerror); 356 } 357 if (uerror == ENOENT || uerror == EJUSTRETURN) { 358 if (cnp->cn_flags & ISWHITEOUT) { 359 iswhiteout = 1; 360 } else if (lowerdvp != NULLVP) { 361 lerror = VOP_GETATTR(upperdvp, &va, 362 cnp->cn_cred, cnp->cn_lwp); 363 if (lerror == 0 && (va.va_flags & OPAQUE)) 364 iswhiteout = 1; 365 } 366 } 367 } else { 368 uerror = ENOENT; 369 } 370 371 /* 372 * in a similar way to the upper layer, do the lookup 373 * in the lower layer. this time, if there is some 374 * component magic going on, then vput whatever we got 375 * back from the upper layer and return the lower vnode 376 * instead. 377 */ 378 if (lowerdvp != NULLVP && !iswhiteout) { 379 int nameiop; 380 381 vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY); 382 383 /* 384 * Only do a LOOKUP on the bottom node, since 385 * we won't be making changes to it anyway. 386 */ 387 nameiop = cnp->cn_nameiop; 388 cnp->cn_nameiop = LOOKUP; 389 if (um->um_op == UNMNT_BELOW) { 390 saved_cred = cnp->cn_cred; 391 cnp->cn_cred = um->um_cred; 392 } 393 /* 394 * we shouldn't have to worry about locking interactions 395 * between the lower layer and our union layer (w.r.t. 396 * `..' processing) because we don't futz with lowervp 397 * locks in the union-node instantiation code path. 398 */ 399 lerror = union_lookup1(um->um_lowervp, &lowerdvp, 400 &lowervp, cnp); 401 if (um->um_op == UNMNT_BELOW) 402 cnp->cn_cred = saved_cred; 403 cnp->cn_nameiop = nameiop; 404 405 if (lowervp != lowerdvp) 406 VOP_UNLOCK(lowerdvp, 0); 407 408 if (cnp->cn_consume != 0) { 409 if (uppervp != NULLVP) { 410 if (uppervp == upperdvp) 411 vrele(uppervp); 412 else 413 vput(uppervp); 414 uppervp = NULLVP; 415 } 416 *ap->a_vpp = lowervp; 417 if (!lockparent) 418 cnp->cn_flags &= ~LOCKPARENT; 419 return (lerror); 420 } 421 } else { 422 lerror = ENOENT; 423 if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) { 424 lowervp = LOWERVP(dun->un_pvp); 425 if (lowervp != NULLVP) { 426 VREF(lowervp); 427 vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY); 428 lerror = 0; 429 } 430 } 431 } 432 433 if (!lockparent) 434 cnp->cn_flags &= ~LOCKPARENT; 435 436 /* 437 * EJUSTRETURN is used by underlying filesystems to indicate that 438 * a directory modification op was started successfully. 439 * This will only happen in the upper layer, since 440 * the lower layer only does LOOKUPs. 441 * If this union is mounted read-only, bounce it now. 442 */ 443 444 if ((uerror == EJUSTRETURN) && (cnp->cn_flags & ISLASTCN) && 445 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 446 ((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME))) 447 uerror = EROFS; 448 449 /* 450 * at this point, we have uerror and lerror indicating 451 * possible errors with the lookups in the upper and lower 452 * layers. additionally, uppervp and lowervp are (locked) 453 * references to existing vnodes in the upper and lower layers. 454 * 455 * there are now three cases to consider. 456 * 1. if both layers returned an error, then return whatever 457 * error the upper layer generated. 458 * 459 * 2. if the top layer failed and the bottom layer succeeded 460 * then two subcases occur. 461 * a. the bottom vnode is not a directory, in which 462 * case just return a new union vnode referencing 463 * an empty top layer and the existing bottom layer. 464 * b. the bottom vnode is a directory, in which case 465 * create a new directory in the top-level and 466 * continue as in case 3. 467 * 468 * 3. if the top layer succeeded then return a new union 469 * vnode referencing whatever the new top layer and 470 * whatever the bottom layer returned. 471 */ 472 473 *ap->a_vpp = NULLVP; 474 475 476 /* case 1. */ 477 if ((uerror != 0) && (lerror != 0)) { 478 return (uerror); 479 } 480 481 /* case 2. */ 482 if (uerror != 0 /* && (lerror == 0) */ ) { 483 if (lowervp->v_type == VDIR) { /* case 2b. */ 484 /* 485 * We may be racing another process to make the 486 * upper-level shadow directory. Be careful with 487 * locks/etc! 488 */ 489 dun->un_flags &= ~UN_ULOCK; 490 VOP_UNLOCK(upperdvp, 0); 491 uerror = union_mkshadow(um, upperdvp, cnp, &uppervp); 492 vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY); 493 dun->un_flags |= UN_ULOCK; 494 495 if (uerror) { 496 if (lowervp != NULLVP) { 497 vput(lowervp); 498 lowervp = NULLVP; 499 } 500 return (uerror); 501 } 502 } 503 } 504 505 if (lowervp != NULLVP) 506 VOP_UNLOCK(lowervp, 0); 507 508 error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, 509 uppervp, lowervp, 1, cnp->cn_lwp); 510 511 if (error) { 512 if (uppervp != NULLVP) 513 vput(uppervp); 514 if (lowervp != NULLVP) 515 vrele(lowervp); 516 } else { 517 if (*ap->a_vpp != dvp) 518 if (!lockparent || !(cnp->cn_flags & ISLASTCN)) 519 VOP_UNLOCK(dvp, 0); 520 if (cnp->cn_namelen == 1 && 521 cnp->cn_nameptr[0] == '.' && 522 *ap->a_vpp != dvp) { 523 panic("union_lookup -> . (%p) != startdir (%p)", 524 ap->a_vpp, dvp); 525 } 526 } 527 528 return (error); 529} 530 531int 532union_create(v) 533 void *v; 534{ 535 struct vop_create_args /* { 536 struct vnode *a_dvp; 537 struct vnode **a_vpp; 538 struct componentname *a_cnp; 539 struct vattr *a_vap; 540 } */ *ap = v; 541 struct union_node *un = VTOUNION(ap->a_dvp); 542 struct vnode *dvp = un->un_uppervp; 543 struct componentname *cnp = ap->a_cnp; 544 545 if (dvp != NULLVP) { 546 int error; 547 struct vnode *vp; 548 struct mount *mp; 549 550 FIXUP(un); 551 552 VREF(dvp); 553 un->un_flags |= UN_KLOCK; 554 mp = ap->a_dvp->v_mount; 555 vput(ap->a_dvp); 556 error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap); 557 if (error) 558 return (error); 559 560 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp, 561 NULLVP, 1, cnp->cn_lwp); 562 if (error) 563 vput(vp); 564 return (error); 565 } 566 567 vput(ap->a_dvp); 568 return (EROFS); 569} 570 571int 572union_whiteout(v) 573 void *v; 574{ 575 struct vop_whiteout_args /* { 576 struct vnode *a_dvp; 577 struct componentname *a_cnp; 578 int a_flags; 579 } */ *ap = v; 580 struct union_node *un = VTOUNION(ap->a_dvp); 581 struct componentname *cnp = ap->a_cnp; 582 583 if (un->un_uppervp == NULLVP) 584 return (EOPNOTSUPP); 585 586 FIXUP(un); 587 return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags)); 588} 589 590int 591union_mknod(v) 592 void *v; 593{ 594 struct vop_mknod_args /* { 595 struct vnode *a_dvp; 596 struct vnode **a_vpp; 597 struct componentname *a_cnp; 598 struct vattr *a_vap; 599 } */ *ap = v; 600 struct union_node *un = VTOUNION(ap->a_dvp); 601 struct vnode *dvp = un->un_uppervp; 602 struct componentname *cnp = ap->a_cnp; 603 604 if (dvp != NULLVP) { 605 int error; 606 struct vnode *vp; 607 struct mount *mp; 608 609 FIXUP(un); 610 611 VREF(dvp); 612 un->un_flags |= UN_KLOCK; 613 mp = ap->a_dvp->v_mount; 614 vput(ap->a_dvp); 615 error = VOP_MKNOD(dvp, &vp, cnp, ap->a_vap); 616 if (error) 617 return (error); 618 619 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, 620 cnp, vp, NULLVP, 1, cnp->cn_lwp); 621 if (error) 622 vput(vp); 623 return (error); 624 } 625 626 vput(ap->a_dvp); 627 return (EROFS); 628} 629 630int 631union_open(v) 632 void *v; 633{ 634 struct vop_open_args /* { 635 struct vnodeop_desc *a_desc; 636 struct vnode *a_vp; 637 int a_mode; 638 struct ucred *a_cred; 639 struct lwp *a_l; 640 } */ *ap = v; 641 struct union_node *un = VTOUNION(ap->a_vp); 642 struct vnode *tvp; 643 int mode = ap->a_mode; 644 struct ucred *cred = ap->a_cred; 645 struct lwp *l = ap->a_l; 646 int error; 647 648 /* 649 * If there is an existing upper vp then simply open that. 650 */ 651 tvp = un->un_uppervp; 652 if (tvp == NULLVP) { 653 /* 654 * If the lower vnode is being opened for writing, then 655 * copy the file contents to the upper vnode and open that, 656 * otherwise can simply open the lower vnode. 657 */ 658 tvp = un->un_lowervp; 659 if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) { 660 error = union_copyup(un, (mode&O_TRUNC) == 0, cred, l); 661 if (error == 0) 662 error = VOP_OPEN(un->un_uppervp, mode, cred, l); 663 return (error); 664 } 665 666 /* 667 * Just open the lower vnode, but check for nodev mount flag 668 */ 669 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 670 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 671 return ENXIO; 672 un->un_openl++; 673 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); 674 error = VOP_OPEN(tvp, mode, cred, l); 675 VOP_UNLOCK(tvp, 0); 676 677 return (error); 678 } 679 /* 680 * Just open the upper vnode, checking for nodev mount flag first 681 */ 682 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 683 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 684 return ENXIO; 685 686 FIXUP(un); 687 688 error = VOP_OPEN(tvp, mode, cred, l); 689 690 return (error); 691} 692 693int 694union_close(v) 695 void *v; 696{ 697 struct vop_close_args /* { 698 struct vnode *a_vp; 699 int a_fflag; 700 struct ucred *a_cred; 701 struct lwp *a_l; 702 } */ *ap = v; 703 struct union_node *un = VTOUNION(ap->a_vp); 704 struct vnode *vp; 705 706 vp = un->un_uppervp; 707 if (vp == NULLVP) { 708#ifdef UNION_DIAGNOSTIC 709 if (un->un_openl <= 0) 710 panic("union: un_openl cnt"); 711#endif 712 --un->un_openl; 713 vp = un->un_lowervp; 714 } 715 716#ifdef DIAGNOSTIC 717 if (vp == NULLVP) { 718 vprint("empty union vnode", vp); 719 panic("union_close empty vnode"); 720 } 721#endif 722 723 ap->a_vp = vp; 724 return (VCALL(vp, VOFFSET(vop_close), ap)); 725} 726 727/* 728 * Check access permission on the union vnode. 729 * The access check being enforced is to check 730 * against both the underlying vnode, and any 731 * copied vnode. This ensures that no additional 732 * file permissions are given away simply because 733 * the user caused an implicit file copy. 734 */ 735int 736union_access(v) 737 void *v; 738{ 739 struct vop_access_args /* { 740 struct vnodeop_desc *a_desc; 741 struct vnode *a_vp; 742 int a_mode; 743 struct ucred *a_cred; 744 struct lwp *a_l; 745 } */ *ap = v; 746 struct vnode *vp = ap->a_vp; 747 struct union_node *un = VTOUNION(vp); 748 int error = EACCES; 749 struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount); 750 751 /* 752 * Disallow write attempts on read-only file systems; 753 * unless the file is a socket, fifo, or a block or 754 * character device resident on the file system. 755 */ 756 if (ap->a_mode & VWRITE) { 757 switch (vp->v_type) { 758 case VDIR: 759 case VLNK: 760 case VREG: 761 if (vp->v_mount->mnt_flag & MNT_RDONLY) 762 return (EROFS); 763 break; 764 case VBAD: 765 case VBLK: 766 case VCHR: 767 case VSOCK: 768 case VFIFO: 769 case VNON: 770 default: 771 break; 772 } 773 } 774 775 776 if ((vp = un->un_uppervp) != NULLVP) { 777 FIXUP(un); 778 ap->a_vp = vp; 779 return (VCALL(vp, VOFFSET(vop_access), ap)); 780 } 781 782 if ((vp = un->un_lowervp) != NULLVP) { 783 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 784 ap->a_vp = vp; 785 error = VCALL(vp, VOFFSET(vop_access), ap); 786 if (error == 0) { 787 if (um->um_op == UNMNT_BELOW) { 788 ap->a_cred = um->um_cred; 789 error = VCALL(vp, VOFFSET(vop_access), ap); 790 } 791 } 792 VOP_UNLOCK(vp, 0); 793 if (error) 794 return (error); 795 } 796 797 return (error); 798} 799 800/* 801 * We handle getattr only to change the fsid and 802 * track object sizes 803 */ 804int 805union_getattr(v) 806 void *v; 807{ 808 struct vop_getattr_args /* { 809 struct vnode *a_vp; 810 struct vattr *a_vap; 811 struct ucred *a_cred; 812 struct lwp *a_l; 813 } */ *ap = v; 814 int error; 815 struct union_node *un = VTOUNION(ap->a_vp); 816 struct vnode *vp = un->un_uppervp; 817 struct vattr *vap; 818 struct vattr va; 819 820 821 /* 822 * Some programs walk the filesystem hierarchy by counting 823 * links to directories to avoid stat'ing all the time. 824 * This means the link count on directories needs to be "correct". 825 * The only way to do that is to call getattr on both layers 826 * and fix up the link count. The link count will not necessarily 827 * be accurate but will be large enough to defeat the tree walkers. 828 * 829 * To make life more interesting, some filesystems don't keep 830 * track of link counts in the expected way, and return a 831 * link count of `1' for those directories; if either of the 832 * component directories returns a link count of `1', we return a 1. 833 */ 834 835 vap = ap->a_vap; 836 837 vp = un->un_uppervp; 838 if (vp != NULLVP) { 839 /* 840 * It's not clear whether VOP_GETATTR is to be 841 * called with the vnode locked or not. stat() calls 842 * it with (vp) locked, and fstat calls it with 843 * (vp) unlocked. 844 * In the mean time, compensate here by checking 845 * the union_node's lock flag. 846 */ 847 if (un->un_flags & UN_LOCKED) 848 FIXUP(un); 849 850 error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_l); 851 if (error) 852 return (error); 853 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 854 } 855 856 if (vp == NULLVP) { 857 vp = un->un_lowervp; 858 } else if (vp->v_type == VDIR) { 859 vp = un->un_lowervp; 860 if (vp != NULLVP) 861 vap = &va; 862 } else { 863 vp = NULLVP; 864 } 865 866 if (vp != NULLVP) { 867 error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_l); 868 if (error) 869 return (error); 870 union_newsize(ap->a_vp, VNOVAL, vap->va_size); 871 } 872 873 if ((vap != ap->a_vap) && (vap->va_type == VDIR)) { 874 /* 875 * Link count manipulation: 876 * - If both return "2", return 2 (no subdirs) 877 * - If one or the other return "1", return "1" (ENOCLUE) 878 */ 879 if ((ap->a_vap->va_nlink == 2) && 880 (vap->va_nlink == 2)) 881 ; 882 else if (ap->a_vap->va_nlink != 1) { 883 if (vap->va_nlink == 1) 884 ap->a_vap->va_nlink = 1; 885 else 886 ap->a_vap->va_nlink += vap->va_nlink; 887 } 888 } 889 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0]; 890 return (0); 891} 892 893int 894union_setattr(v) 895 void *v; 896{ 897 struct vop_setattr_args /* { 898 struct vnode *a_vp; 899 struct vattr *a_vap; 900 struct ucred *a_cred; 901 struct lwp *a_l; 902 } */ *ap = v; 903 struct vattr *vap = ap->a_vap; 904 struct vnode *vp = ap->a_vp; 905 struct union_node *un = VTOUNION(vp); 906 int error; 907 908 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL || 909 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL || 910 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) && 911 (vp->v_mount->mnt_flag & MNT_RDONLY)) 912 return (EROFS); 913 if (vap->va_size != VNOVAL) { 914 switch (vp->v_type) { 915 case VDIR: 916 return (EISDIR); 917 case VCHR: 918 case VBLK: 919 case VSOCK: 920 case VFIFO: 921 break; 922 case VREG: 923 case VLNK: 924 default: 925 /* 926 * Disallow write attempts if the filesystem is 927 * mounted read-only. 928 */ 929 if (vp->v_mount->mnt_flag & MNT_RDONLY) 930 return (EROFS); 931 } 932 } 933 934 /* 935 * Handle case of truncating lower object to zero size, 936 * by creating a zero length upper object. This is to 937 * handle the case of open with O_TRUNC and O_CREAT. 938 */ 939 if ((un->un_uppervp == NULLVP) && 940 /* assert(un->un_lowervp != NULLVP) */ 941 (un->un_lowervp->v_type == VREG)) { 942 error = union_copyup(un, (vap->va_size != 0), 943 ap->a_cred, ap->a_l); 944 if (error) 945 return (error); 946 } 947 948 /* 949 * Try to set attributes in upper layer, 950 * otherwise return read-only filesystem error. 951 */ 952 if (un->un_uppervp != NULLVP) { 953 FIXUP(un); 954 error = VOP_SETATTR(un->un_uppervp, vap, 955 ap->a_cred, ap->a_l); 956 if ((error == 0) && (vap->va_size != VNOVAL)) 957 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 958 } else { 959 error = EROFS; 960 } 961 962 return (error); 963} 964 965int 966union_read(v) 967 void *v; 968{ 969 struct vop_read_args /* { 970 struct vnode *a_vp; 971 struct uio *a_uio; 972 int a_ioflag; 973 struct ucred *a_cred; 974 } */ *ap = v; 975 int error; 976 struct vnode *vp = OTHERVP(ap->a_vp); 977 int dolock = (vp == LOWERVP(ap->a_vp)); 978 979 if (dolock) 980 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 981 else 982 FIXUP(VTOUNION(ap->a_vp)); 983 error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 984 if (dolock) 985 VOP_UNLOCK(vp, 0); 986 987 /* 988 * XXX 989 * perhaps the size of the underlying object has changed under 990 * our feet. take advantage of the offset information present 991 * in the uio structure. 992 */ 993 if (error == 0) { 994 struct union_node *un = VTOUNION(ap->a_vp); 995 off_t cur = ap->a_uio->uio_offset; 996 997 if (vp == un->un_uppervp) { 998 if (cur > un->un_uppersz) 999 union_newsize(ap->a_vp, cur, VNOVAL); 1000 } else { 1001 if (cur > un->un_lowersz) 1002 union_newsize(ap->a_vp, VNOVAL, cur); 1003 } 1004 } 1005 1006 return (error); 1007} 1008 1009int 1010union_write(v) 1011 void *v; 1012{ 1013 struct vop_read_args /* { 1014 struct vnode *a_vp; 1015 struct uio *a_uio; 1016 int a_ioflag; 1017 struct ucred *a_cred; 1018 } */ *ap = v; 1019 int error; 1020 struct vnode *vp; 1021 struct union_node *un = VTOUNION(ap->a_vp); 1022 1023 vp = UPPERVP(ap->a_vp); 1024 if (vp == NULLVP) 1025 panic("union: missing upper layer in write"); 1026 1027 FIXUP(un); 1028 error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 1029 1030 /* 1031 * the size of the underlying object may be changed by the 1032 * write. 1033 */ 1034 if (error == 0) { 1035 off_t cur = ap->a_uio->uio_offset; 1036 1037 if (cur > un->un_uppersz) 1038 union_newsize(ap->a_vp, cur, VNOVAL); 1039 } 1040 1041 return (error); 1042} 1043 1044int 1045union_lease(v) 1046 void *v; 1047{ 1048 struct vop_lease_args /* { 1049 struct vnode *a_vp; 1050 struct lwp *a_l; 1051 struct ucred *a_cred; 1052 int a_flag; 1053 } */ *ap = v; 1054 struct vnode *ovp = OTHERVP(ap->a_vp); 1055 1056 ap->a_vp = ovp; 1057 return (VCALL(ovp, VOFFSET(vop_lease), ap)); 1058} 1059 1060int 1061union_ioctl(v) 1062 void *v; 1063{ 1064 struct vop_ioctl_args /* { 1065 struct vnode *a_vp; 1066 int a_command; 1067 caddr_t a_data; 1068 int a_fflag; 1069 struct ucred *a_cred; 1070 struct lwp *a_l; 1071 } */ *ap = v; 1072 struct vnode *ovp = OTHERVP(ap->a_vp); 1073 1074 ap->a_vp = ovp; 1075 return (VCALL(ovp, VOFFSET(vop_ioctl), ap)); 1076} 1077 1078int 1079union_poll(v) 1080 void *v; 1081{ 1082 struct vop_poll_args /* { 1083 struct vnode *a_vp; 1084 int a_events; 1085 struct lwp *a_l; 1086 } */ *ap = v; 1087 struct vnode *ovp = OTHERVP(ap->a_vp); 1088 1089 ap->a_vp = ovp; 1090 return (VCALL(ovp, VOFFSET(vop_poll), ap)); 1091} 1092 1093int 1094union_revoke(v) 1095 void *v; 1096{ 1097 struct vop_revoke_args /* { 1098 struct vnode *a_vp; 1099 int a_flags; 1100 struct lwp *a_l; 1101 } */ *ap = v; 1102 struct vnode *vp = ap->a_vp; 1103 1104 if (UPPERVP(vp)) 1105 VOP_REVOKE(UPPERVP(vp), ap->a_flags); 1106 if (LOWERVP(vp)) 1107 VOP_REVOKE(LOWERVP(vp), ap->a_flags); 1108 vgone(vp); 1109 return (0); 1110} 1111 1112int 1113union_mmap(v) 1114 void *v; 1115{ 1116 struct vop_mmap_args /* { 1117 struct vnode *a_vp; 1118 int a_fflags; 1119 struct ucred *a_cred; 1120 struct lwp *a_l; 1121 } */ *ap = v; 1122 struct vnode *ovp = OTHERVP(ap->a_vp); 1123 1124 ap->a_vp = ovp; 1125 return (VCALL(ovp, VOFFSET(vop_mmap), ap)); 1126} 1127 1128int 1129union_fsync(v) 1130 void *v; 1131{ 1132 struct vop_fsync_args /* { 1133 struct vnode *a_vp; 1134 struct ucred *a_cred; 1135 int a_flags; 1136 off_t offhi; 1137 off_t offlo; 1138 struct lwp *a_l; 1139 } */ *ap = v; 1140 int error = 0; 1141 struct vnode *targetvp; 1142 1143 /* 1144 * If vinvalbuf is calling us, it's a "shallow fsync" -- don't 1145 * bother syncing the underlying vnodes, since (a) they'll be 1146 * fsync'ed when reclaimed and (b) we could deadlock if 1147 * they're locked; otherwise, pass it through to the 1148 * underlying layer. 1149 */ 1150 if (ap->a_flags & FSYNC_RECLAIM) 1151 return 0; 1152 1153 targetvp = OTHERVP(ap->a_vp); 1154 1155 if (targetvp != NULLVP) { 1156 int dolock = (targetvp == LOWERVP(ap->a_vp)); 1157 1158 if (dolock) 1159 vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY); 1160 else 1161 FIXUP(VTOUNION(ap->a_vp)); 1162 error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags, 1163 ap->a_offlo, ap->a_offhi, ap->a_l); 1164 if (dolock) 1165 VOP_UNLOCK(targetvp, 0); 1166 } 1167 1168 return (error); 1169} 1170 1171int 1172union_seek(v) 1173 void *v; 1174{ 1175 struct vop_seek_args /* { 1176 struct vnode *a_vp; 1177 off_t a_oldoff; 1178 off_t a_newoff; 1179 struct ucred *a_cred; 1180 } */ *ap = v; 1181 struct vnode *ovp = OTHERVP(ap->a_vp); 1182 1183 ap->a_vp = ovp; 1184 return (VCALL(ovp, VOFFSET(vop_seek), ap)); 1185} 1186 1187int 1188union_remove(v) 1189 void *v; 1190{ 1191 struct vop_remove_args /* { 1192 struct vnode *a_dvp; 1193 struct vnode *a_vp; 1194 struct componentname *a_cnp; 1195 } */ *ap = v; 1196 int error; 1197 struct union_node *dun = VTOUNION(ap->a_dvp); 1198 struct union_node *un = VTOUNION(ap->a_vp); 1199 struct componentname *cnp = ap->a_cnp; 1200 1201 if (dun->un_uppervp == NULLVP) 1202 panic("union remove: null upper vnode"); 1203 1204 if (un->un_uppervp != NULLVP) { 1205 struct vnode *dvp = dun->un_uppervp; 1206 struct vnode *vp = un->un_uppervp; 1207 1208 FIXUP(dun); 1209 VREF(dvp); 1210 dun->un_flags |= UN_KLOCK; 1211 vput(ap->a_dvp); 1212 FIXUP(un); 1213 VREF(vp); 1214 un->un_flags |= UN_KLOCK; 1215 vput(ap->a_vp); 1216 1217 if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_lwp)) 1218 cnp->cn_flags |= DOWHITEOUT; 1219 error = VOP_REMOVE(dvp, vp, cnp); 1220 if (!error) 1221 union_removed_upper(un); 1222 } else { 1223 FIXUP(dun); 1224 error = union_mkwhiteout( 1225 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1226 dun->un_uppervp, ap->a_cnp, un->un_path); 1227 vput(ap->a_dvp); 1228 vput(ap->a_vp); 1229 } 1230 1231 return (error); 1232} 1233 1234int 1235union_link(v) 1236 void *v; 1237{ 1238 struct vop_link_args /* { 1239 struct vnode *a_dvp; 1240 struct vnode *a_vp; 1241 struct componentname *a_cnp; 1242 } */ *ap = v; 1243 int error = 0; 1244 struct componentname *cnp = ap->a_cnp; 1245 struct lwp *l = cnp->cn_lwp; 1246 struct union_node *dun; 1247 struct vnode *vp; 1248 struct vnode *dvp; 1249 1250 dun = VTOUNION(ap->a_dvp); 1251 1252#ifdef DIAGNOSTIC 1253 if (!(ap->a_cnp->cn_flags & LOCKPARENT)) { 1254 printf("union_link called without LOCKPARENT set!\n"); 1255 error = EIO; /* need some error code for "caller is a bozo" */ 1256 } else 1257#endif 1258 1259 1260 if (ap->a_dvp->v_op != ap->a_vp->v_op) { 1261 vp = ap->a_vp; 1262 } else { 1263 struct union_node *un = VTOUNION(ap->a_vp); 1264 if (un->un_uppervp == NULLVP) { 1265 /* 1266 * Needs to be copied before we can link it. 1267 */ 1268 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY); 1269 if (dun->un_uppervp == un->un_dirvp) { 1270 dun->un_flags &= ~UN_ULOCK; 1271 VOP_UNLOCK(dun->un_uppervp, 0); 1272 } 1273 error = union_copyup(un, 1, cnp->cn_cred, l); 1274 if (dun->un_uppervp == un->un_dirvp) { 1275 /* 1276 * During copyup, we dropped the lock on the 1277 * dir and invalidated any saved namei lookup 1278 * state for the directory we'll be entering 1279 * the link in. We need to re-run the lookup 1280 * in that directory to reset any state needed 1281 * for VOP_LINK. 1282 * Call relookup on the union-layer to reset 1283 * the state. 1284 */ 1285 vp = NULLVP; 1286 if (dun->un_uppervp == NULLVP) 1287 panic("union: null upperdvp?"); 1288 /* 1289 * relookup starts with an unlocked node, 1290 * and since LOCKPARENT is set returns 1291 * the starting directory locked. 1292 */ 1293 VOP_UNLOCK(ap->a_dvp, 0); 1294 error = relookup(ap->a_dvp, &vp, ap->a_cnp); 1295 if (error) { 1296 vrele(ap->a_dvp); 1297 VOP_UNLOCK(ap->a_vp, 0); 1298 return EROFS; /* ? */ 1299 } 1300 if (vp != NULLVP) { 1301 /* 1302 * The name we want to create has 1303 * mysteriously appeared (a race?) 1304 */ 1305 error = EEXIST; 1306 VOP_UNLOCK(ap->a_vp, 0); 1307 goto croak; 1308 } 1309 } 1310 VOP_UNLOCK(ap->a_vp, 0); 1311 } 1312 vp = un->un_uppervp; 1313 } 1314 1315 dvp = dun->un_uppervp; 1316 if (dvp == NULLVP) 1317 error = EROFS; 1318 1319 if (error) { 1320croak: 1321 vput(ap->a_dvp); 1322 return (error); 1323 } 1324 1325 FIXUP(dun); 1326 VREF(dvp); 1327 dun->un_flags |= UN_KLOCK; 1328 vput(ap->a_dvp); 1329 1330 return (VOP_LINK(dvp, vp, cnp)); 1331} 1332 1333int 1334union_rename(v) 1335 void *v; 1336{ 1337 struct vop_rename_args /* { 1338 struct vnode *a_fdvp; 1339 struct vnode *a_fvp; 1340 struct componentname *a_fcnp; 1341 struct vnode *a_tdvp; 1342 struct vnode *a_tvp; 1343 struct componentname *a_tcnp; 1344 } */ *ap = v; 1345 int error; 1346 1347 struct vnode *fdvp = ap->a_fdvp; 1348 struct vnode *fvp = ap->a_fvp; 1349 struct vnode *tdvp = ap->a_tdvp; 1350 struct vnode *tvp = ap->a_tvp; 1351 1352 if (fdvp->v_op == union_vnodeop_p) { /* always true */ 1353 struct union_node *un = VTOUNION(fdvp); 1354 if (un->un_uppervp == NULLVP) { 1355 /* 1356 * this should never happen in normal 1357 * operation but might if there was 1358 * a problem creating the top-level shadow 1359 * directory. 1360 */ 1361 error = EXDEV; 1362 goto bad; 1363 } 1364 1365 fdvp = un->un_uppervp; 1366 VREF(fdvp); 1367 vrele(ap->a_fdvp); 1368 } 1369 1370 if (fvp->v_op == union_vnodeop_p) { /* always true */ 1371 struct union_node *un = VTOUNION(fvp); 1372 if (un->un_uppervp == NULLVP) { 1373 /* XXX: should do a copyup */ 1374 error = EXDEV; 1375 goto bad; 1376 } 1377 1378 if (un->un_lowervp != NULLVP) 1379 ap->a_fcnp->cn_flags |= DOWHITEOUT; 1380 1381 fvp = un->un_uppervp; 1382 VREF(fvp); 1383 vrele(ap->a_fvp); 1384 } 1385 1386 if (tdvp->v_op == union_vnodeop_p) { 1387 struct union_node *un = VTOUNION(tdvp); 1388 if (un->un_uppervp == NULLVP) { 1389 /* 1390 * this should never happen in normal 1391 * operation but might if there was 1392 * a problem creating the top-level shadow 1393 * directory. 1394 */ 1395 error = EXDEV; 1396 goto bad; 1397 } 1398 1399 tdvp = un->un_uppervp; 1400 VREF(tdvp); 1401 un->un_flags |= UN_KLOCK; 1402 vput(ap->a_tdvp); 1403 } 1404 1405 if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) { 1406 struct union_node *un = VTOUNION(tvp); 1407 1408 tvp = un->un_uppervp; 1409 if (tvp != NULLVP) { 1410 VREF(tvp); 1411 un->un_flags |= UN_KLOCK; 1412 } 1413 vput(ap->a_tvp); 1414 } 1415 1416 return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp)); 1417 1418bad: 1419 vrele(fdvp); 1420 vrele(fvp); 1421 vput(tdvp); 1422 if (tvp != NULLVP) 1423 vput(tvp); 1424 1425 return (error); 1426} 1427 1428int 1429union_mkdir(v) 1430 void *v; 1431{ 1432 struct vop_mkdir_args /* { 1433 struct vnode *a_dvp; 1434 struct vnode **a_vpp; 1435 struct componentname *a_cnp; 1436 struct vattr *a_vap; 1437 } */ *ap = v; 1438 struct union_node *un = VTOUNION(ap->a_dvp); 1439 struct vnode *dvp = un->un_uppervp; 1440 struct componentname *cnp = ap->a_cnp; 1441 1442 if (dvp != NULLVP) { 1443 int error; 1444 struct vnode *vp; 1445 1446 FIXUP(un); 1447 VREF(dvp); 1448 un->un_flags |= UN_KLOCK; 1449 VOP_UNLOCK(ap->a_dvp, 0); 1450 error = VOP_MKDIR(dvp, &vp, cnp, ap->a_vap); 1451 if (error) { 1452 vrele(ap->a_dvp); 1453 return (error); 1454 } 1455 1456 error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, 1457 NULLVP, cnp, vp, NULLVP, 1, cnp->cn_lwp); 1458 vrele(ap->a_dvp); 1459 if (error) 1460 vput(vp); 1461 return (error); 1462 } 1463 1464 vput(ap->a_dvp); 1465 return (EROFS); 1466} 1467 1468int 1469union_rmdir(v) 1470 void *v; 1471{ 1472 struct vop_rmdir_args /* { 1473 struct vnode *a_dvp; 1474 struct vnode *a_vp; 1475 struct componentname *a_cnp; 1476 } */ *ap = v; 1477 int error; 1478 struct union_node *dun = VTOUNION(ap->a_dvp); 1479 struct union_node *un = VTOUNION(ap->a_vp); 1480 struct componentname *cnp = ap->a_cnp; 1481 1482 if (dun->un_uppervp == NULLVP) 1483 panic("union rmdir: null upper vnode"); 1484 1485 if (un->un_uppervp != NULLVP) { 1486 struct vnode *dvp = dun->un_uppervp; 1487 struct vnode *vp = un->un_uppervp; 1488 1489 FIXUP(dun); 1490 VREF(dvp); 1491 dun->un_flags |= UN_KLOCK; 1492 vput(ap->a_dvp); 1493 FIXUP(un); 1494 VREF(vp); 1495 un->un_flags |= UN_KLOCK; 1496 vput(ap->a_vp); 1497 1498 if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_lwp)) 1499 cnp->cn_flags |= DOWHITEOUT; 1500 error = VOP_RMDIR(dvp, vp, ap->a_cnp); 1501 if (!error) 1502 union_removed_upper(un); 1503 } else { 1504 FIXUP(dun); 1505 error = union_mkwhiteout( 1506 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1507 dun->un_uppervp, ap->a_cnp, un->un_path); 1508 vput(ap->a_dvp); 1509 vput(ap->a_vp); 1510 } 1511 1512 return (error); 1513} 1514 1515int 1516union_symlink(v) 1517 void *v; 1518{ 1519 struct vop_symlink_args /* { 1520 struct vnode *a_dvp; 1521 struct vnode **a_vpp; 1522 struct componentname *a_cnp; 1523 struct vattr *a_vap; 1524 char *a_target; 1525 } */ *ap = v; 1526 struct union_node *un = VTOUNION(ap->a_dvp); 1527 struct vnode *dvp = un->un_uppervp; 1528 struct componentname *cnp = ap->a_cnp; 1529 1530 if (dvp != NULLVP) { 1531 int error; 1532 1533 FIXUP(un); 1534 VREF(dvp); 1535 un->un_flags |= UN_KLOCK; 1536 vput(ap->a_dvp); 1537 error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap, 1538 ap->a_target); 1539 return (error); 1540 } 1541 1542 vput(ap->a_dvp); 1543 return (EROFS); 1544} 1545 1546/* 1547 * union_readdir works in concert with getdirentries and 1548 * readdir(3) to provide a list of entries in the unioned 1549 * directories. getdirentries is responsible for walking 1550 * down the union stack. readdir(3) is responsible for 1551 * eliminating duplicate names from the returned data stream. 1552 */ 1553int 1554union_readdir(v) 1555 void *v; 1556{ 1557 struct vop_readdir_args /* { 1558 struct vnodeop_desc *a_desc; 1559 struct vnode *a_vp; 1560 struct uio *a_uio; 1561 struct ucred *a_cred; 1562 int *a_eofflag; 1563 u_long *a_cookies; 1564 int a_ncookies; 1565 } */ *ap = v; 1566 struct union_node *un = VTOUNION(ap->a_vp); 1567 struct vnode *uvp = un->un_uppervp; 1568 1569 if (uvp == NULLVP) 1570 return (0); 1571 1572 FIXUP(un); 1573 ap->a_vp = uvp; 1574 return (VCALL(uvp, VOFFSET(vop_readdir), ap)); 1575} 1576 1577int 1578union_readlink(v) 1579 void *v; 1580{ 1581 struct vop_readlink_args /* { 1582 struct vnode *a_vp; 1583 struct uio *a_uio; 1584 struct ucred *a_cred; 1585 } */ *ap = v; 1586 int error; 1587 struct vnode *vp = OTHERVP(ap->a_vp); 1588 int dolock = (vp == LOWERVP(ap->a_vp)); 1589 1590 if (dolock) 1591 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1592 else 1593 FIXUP(VTOUNION(ap->a_vp)); 1594 ap->a_vp = vp; 1595 error = VCALL(vp, VOFFSET(vop_readlink), ap); 1596 if (dolock) 1597 VOP_UNLOCK(vp, 0); 1598 1599 return (error); 1600} 1601 1602int 1603union_abortop(v) 1604 void *v; 1605{ 1606 struct vop_abortop_args /* { 1607 struct vnode *a_dvp; 1608 struct componentname *a_cnp; 1609 } */ *ap = v; 1610 int error; 1611 struct vnode *vp = OTHERVP(ap->a_dvp); 1612 struct union_node *un = VTOUNION(ap->a_dvp); 1613 int islocked = un->un_flags & UN_LOCKED; 1614 int dolock = (vp == LOWERVP(ap->a_dvp)); 1615 1616 if (islocked) { 1617 if (dolock) 1618 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1619 else 1620 FIXUP(VTOUNION(ap->a_dvp)); 1621 } 1622 ap->a_dvp = vp; 1623 error = VCALL(vp, VOFFSET(vop_abortop), ap); 1624 if (islocked && dolock) 1625 VOP_UNLOCK(vp, 0); 1626 1627 return (error); 1628} 1629 1630int 1631union_inactive(v) 1632 void *v; 1633{ 1634 struct vop_inactive_args /* { 1635 struct vnode *a_vp; 1636 struct lwp *a_l; 1637 } */ *ap = v; 1638 struct vnode *vp = ap->a_vp; 1639 struct union_node *un = VTOUNION(vp); 1640 struct vnode **vpp; 1641 1642 /* 1643 * Do nothing (and _don't_ bypass). 1644 * Wait to vrele lowervp until reclaim, 1645 * so that until then our union_node is in the 1646 * cache and reusable. 1647 * 1648 * NEEDSWORK: Someday, consider inactive'ing 1649 * the lowervp and then trying to reactivate it 1650 * with capabilities (v_id) 1651 * like they do in the name lookup cache code. 1652 * That's too much work for now. 1653 */ 1654 1655 if (un->un_dircache != 0) { 1656 for (vpp = un->un_dircache; *vpp != NULLVP; vpp++) 1657 vrele(*vpp); 1658 free(un->un_dircache, M_TEMP); 1659 un->un_dircache = 0; 1660 } 1661 1662 VOP_UNLOCK(vp, 0); 1663 1664 if ((un->un_flags & UN_CACHED) == 0) 1665 vgone(vp); 1666 1667 return (0); 1668} 1669 1670int 1671union_reclaim(v) 1672 void *v; 1673{ 1674 struct vop_reclaim_args /* { 1675 struct vnode *a_vp; 1676 } */ *ap = v; 1677 1678 union_freevp(ap->a_vp); 1679 1680 return (0); 1681} 1682 1683int 1684union_lock(v) 1685 void *v; 1686{ 1687 struct vop_lock_args /* { 1688 struct vnode *a_vp; 1689 int a_flags; 1690 } */ *ap = v; 1691 struct vnode *vp = ap->a_vp; 1692 int flags = ap->a_flags; 1693 struct union_node *un; 1694 int error; 1695#ifdef DIAGNOSTIC 1696 int drain = 0; 1697#endif 1698 1699 genfs_nolock(ap); 1700 /* 1701 * Need to do real lockmgr-style locking here. 1702 * in the mean time, draining won't work quite right, 1703 * which could lead to a few race conditions. 1704 * the following test was here, but is not quite right, we 1705 * still need to take the lock: 1706 if ((flags & LK_TYPE_MASK) == LK_DRAIN) 1707 return (0); 1708 */ 1709 flags &= ~LK_INTERLOCK; 1710 1711 un = VTOUNION(vp); 1712#ifdef DIAGNOSTIC 1713 if (un->un_flags & (UN_DRAINING|UN_DRAINED)) { 1714 if (un->un_flags & UN_DRAINED) 1715 panic("union: %p: warning: locking decommissioned lock", vp); 1716 if ((flags & LK_TYPE_MASK) != LK_RELEASE) 1717 panic("union: %p: non-release on draining lock: %d", 1718 vp, flags & LK_TYPE_MASK); 1719 un->un_flags &= ~UN_DRAINING; 1720 if ((flags & LK_REENABLE) == 0) 1721 un->un_flags |= UN_DRAINED; 1722 } 1723#endif 1724 1725 /* 1726 * Don't pass DRAIN through to sub-vnode lock; keep track of 1727 * DRAIN state at this level, and just get an exclusive lock 1728 * on the underlying vnode. 1729 */ 1730 if ((flags & LK_TYPE_MASK) == LK_DRAIN) { 1731#ifdef DIAGNOSTIC 1732 drain = 1; 1733#endif 1734 flags = LK_EXCLUSIVE | (flags & ~LK_TYPE_MASK); 1735 } 1736start: 1737 un = VTOUNION(vp); 1738 1739 if (un->un_uppervp != NULLVP) { 1740 if (((un->un_flags & UN_ULOCK) == 0) && 1741 (vp->v_usecount != 0)) { 1742 /* 1743 * We MUST always use the order of: take upper 1744 * vp lock, manipulate union node flags, drop 1745 * upper vp lock. This code must not be an 1746 */ 1747 error = vn_lock(un->un_uppervp, flags); 1748 if (error) 1749 return (error); 1750 un->un_flags |= UN_ULOCK; 1751 } 1752#ifdef DIAGNOSTIC 1753 if (un->un_flags & UN_KLOCK) { 1754 vprint("union: dangling klock", vp); 1755 panic("union: dangling upper lock (%p)", vp); 1756 } 1757#endif 1758 } 1759 1760 /* XXX ignores LK_NOWAIT */ 1761 if (un->un_flags & UN_LOCKED) { 1762#ifdef DIAGNOSTIC 1763 if (curproc && un->un_pid == curproc->p_pid && 1764 un->un_pid > -1 && curproc->p_pid > -1) 1765 panic("union: locking against myself"); 1766#endif 1767 un->un_flags |= UN_WANTED; 1768 tsleep((caddr_t)&un->un_flags, PINOD, "unionlk2", 0); 1769 goto start; 1770 } 1771 1772#ifdef DIAGNOSTIC 1773 if (curproc) 1774 un->un_pid = curproc->p_pid; 1775 else 1776 un->un_pid = -1; 1777 if (drain) 1778 un->un_flags |= UN_DRAINING; 1779#endif 1780 1781 un->un_flags |= UN_LOCKED; 1782 return (0); 1783} 1784 1785/* 1786 * When operations want to vput() a union node yet retain a lock on 1787 * the upper vnode (say, to do some further operations like link(), 1788 * mkdir(), ...), they set UN_KLOCK on the union node, then call 1789 * vput() which calls VOP_UNLOCK() and comes here. union_unlock() 1790 * unlocks the union node (leaving the upper vnode alone), clears the 1791 * KLOCK flag, and then returns to vput(). The caller then does whatever 1792 * is left to do with the upper vnode, and ensures that it gets unlocked. 1793 * 1794 * If UN_KLOCK isn't set, then the upper vnode is unlocked here. 1795 */ 1796int 1797union_unlock(v) 1798 void *v; 1799{ 1800 struct vop_unlock_args /* { 1801 struct vnode *a_vp; 1802 int a_flags; 1803 } */ *ap = v; 1804 struct union_node *un = VTOUNION(ap->a_vp); 1805 1806#ifdef DIAGNOSTIC 1807 if ((un->un_flags & UN_LOCKED) == 0) 1808 panic("union: unlock unlocked node"); 1809 if (curproc && un->un_pid != curproc->p_pid && 1810 curproc->p_pid > -1 && un->un_pid > -1) 1811 panic("union: unlocking other process's union node"); 1812 if (un->un_flags & UN_DRAINED) 1813 panic("union: %p: warning: unlocking decommissioned lock", ap->a_vp); 1814#endif 1815 1816 un->un_flags &= ~UN_LOCKED; 1817 1818 if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK) 1819 VOP_UNLOCK(un->un_uppervp, 0); 1820 1821 un->un_flags &= ~(UN_ULOCK|UN_KLOCK); 1822 1823 if (un->un_flags & UN_WANTED) { 1824 un->un_flags &= ~UN_WANTED; 1825 wakeup((caddr_t) &un->un_flags); 1826 } 1827 1828#ifdef DIAGNOSTIC 1829 un->un_pid = 0; 1830 if (un->un_flags & UN_DRAINING) { 1831 un->un_flags |= UN_DRAINED; 1832 un->un_flags &= ~UN_DRAINING; 1833 } 1834#endif 1835 genfs_nounlock(ap); 1836 1837 return (0); 1838} 1839 1840int 1841union_bmap(v) 1842 void *v; 1843{ 1844 struct vop_bmap_args /* { 1845 struct vnode *a_vp; 1846 daddr_t a_bn; 1847 struct vnode **a_vpp; 1848 daddr_t *a_bnp; 1849 int *a_runp; 1850 } */ *ap = v; 1851 int error; 1852 struct vnode *vp = OTHERVP(ap->a_vp); 1853 int dolock = (vp == LOWERVP(ap->a_vp)); 1854 1855 if (dolock) 1856 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1857 else 1858 FIXUP(VTOUNION(ap->a_vp)); 1859 ap->a_vp = vp; 1860 error = VCALL(vp, VOFFSET(vop_bmap), ap); 1861 if (dolock) 1862 VOP_UNLOCK(vp, 0); 1863 1864 return (error); 1865} 1866 1867int 1868union_print(v) 1869 void *v; 1870{ 1871 struct vop_print_args /* { 1872 struct vnode *a_vp; 1873 } */ *ap = v; 1874 struct vnode *vp = ap->a_vp; 1875 1876 printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n", 1877 vp, UPPERVP(vp), LOWERVP(vp)); 1878 if (UPPERVP(vp) != NULLVP) 1879 vprint("union: upper", UPPERVP(vp)); 1880 if (LOWERVP(vp) != NULLVP) 1881 vprint("union: lower", LOWERVP(vp)); 1882 if (VTOUNION(vp)->un_dircache) { 1883 struct vnode **vpp; 1884 for (vpp = VTOUNION(vp)->un_dircache; *vpp != NULLVP; vpp++) 1885 vprint("dircache:", *vpp); 1886 } 1887 1888 return (0); 1889} 1890 1891int 1892union_islocked(v) 1893 void *v; 1894{ 1895 struct vop_islocked_args /* { 1896 struct vnode *a_vp; 1897 } */ *ap = v; 1898 1899 return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0); 1900} 1901 1902int 1903union_pathconf(v) 1904 void *v; 1905{ 1906 struct vop_pathconf_args /* { 1907 struct vnode *a_vp; 1908 int a_name; 1909 int *a_retval; 1910 } */ *ap = v; 1911 int error; 1912 struct vnode *vp = OTHERVP(ap->a_vp); 1913 int dolock = (vp == LOWERVP(ap->a_vp)); 1914 1915 if (dolock) 1916 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1917 else 1918 FIXUP(VTOUNION(ap->a_vp)); 1919 ap->a_vp = vp; 1920 error = VCALL(vp, VOFFSET(vop_pathconf), ap); 1921 if (dolock) 1922 VOP_UNLOCK(vp, 0); 1923 1924 return (error); 1925} 1926 1927int 1928union_advlock(v) 1929 void *v; 1930{ 1931 struct vop_advlock_args /* { 1932 struct vnode *a_vp; 1933 caddr_t a_id; 1934 int a_op; 1935 struct flock *a_fl; 1936 int a_flags; 1937 } */ *ap = v; 1938 struct vnode *ovp = OTHERVP(ap->a_vp); 1939 1940 ap->a_vp = ovp; 1941 return (VCALL(ovp, VOFFSET(vop_advlock), ap)); 1942} 1943 1944 1945/* 1946 * XXX - vop_strategy must be hand coded because it has no 1947 * vnode in its arguments. 1948 * This goes away with a merged VM/buffer cache. 1949 */ 1950int 1951union_strategy(v) 1952 void *v; 1953{ 1954 struct vop_strategy_args /* { 1955 struct buf *a_bp; 1956 } */ *ap = v; 1957 struct buf *bp = ap->a_bp; 1958 int error; 1959 struct vnode *savedvp; 1960 1961 savedvp = bp->b_vp; 1962 bp->b_vp = OTHERVP(bp->b_vp); 1963 1964#ifdef DIAGNOSTIC 1965 if (bp->b_vp == NULLVP) 1966 panic("union_strategy: nil vp"); 1967 if (((bp->b_flags & B_READ) == 0) && 1968 (bp->b_vp == LOWERVP(savedvp))) 1969 panic("union_strategy: writing to lowervp"); 1970#endif 1971 1972 error = VOP_STRATEGY(bp); 1973 bp->b_vp = savedvp; 1974 1975 return (error); 1976} 1977 1978int 1979union_getpages(v) 1980 void *v; 1981{ 1982 struct vop_getpages_args /* { 1983 struct vnode *a_vp; 1984 voff_t a_offset; 1985 struct vm_page **a_m; 1986 int *a_count; 1987 int a_centeridx; 1988 vm_prot_t a_access_type; 1989 int a_advice; 1990 int a_flags; 1991 } */ *ap = v; 1992 struct vnode *vp = ap->a_vp; 1993 int error; 1994 1995 /* 1996 * just pass the request on to the underlying layer. 1997 */ 1998 1999 if (ap->a_flags & PGO_LOCKED) { 2000 return EBUSY; 2001 } 2002 ap->a_vp = OTHERVP(vp); 2003 simple_unlock(&vp->v_interlock); 2004 simple_lock(&ap->a_vp->v_interlock); 2005 error = VCALL(ap->a_vp, VOFFSET(vop_getpages), ap); 2006 return error; 2007} 2008 2009int 2010union_putpages(v) 2011 void *v; 2012{ 2013 struct vop_putpages_args /* { 2014 struct vnode *a_vp; 2015 voff_t a_offlo; 2016 voff_t a_offhi; 2017 int a_flags; 2018 } */ *ap = v; 2019 struct vnode *vp = ap->a_vp; 2020 int error; 2021 2022 /* 2023 * just pass the request on to the underlying layer. 2024 */ 2025 2026 ap->a_vp = OTHERVP(vp); 2027 simple_unlock(&vp->v_interlock); 2028 simple_lock(&ap->a_vp->v_interlock); 2029 error = VCALL(ap->a_vp, VOFFSET(vop_putpages), ap); 2030 return error; 2031} 2032 2033int 2034union_kqfilter(void *v) 2035{ 2036 struct vop_kqfilter_args /* { 2037 struct vnode *a_vp; 2038 struct knote *a_kn; 2039 } */ *ap = v; 2040 int error; 2041 2042 /* 2043 * We watch either the upper layer file (if it already exists), 2044 * or the lower layer one. If there is lower layer file only 2045 * at this moment, we will keep watching that lower layer file 2046 * even if upper layer file would be created later on. 2047 */ 2048 if (UPPERVP(ap->a_vp)) 2049 error = VOP_KQFILTER(UPPERVP(ap->a_vp), ap->a_kn); 2050 else if (LOWERVP(ap->a_vp)) 2051 error = VOP_KQFILTER(LOWERVP(ap->a_vp), ap->a_kn); 2052 else { 2053 /* panic? */ 2054 error = EOPNOTSUPP; 2055 } 2056 2057 return (error); 2058} 2059