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sys/fs/union/union_vnops.c
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1 /* $NetBSD: union_vnops.c,v 1.8 2004/01/25 18:06:48 hannken 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 1.8 2004/01/25 18:06:48 hannken 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 <fs/union/union.h> 91 #include <miscfs/genfs/genfs.h> 92 93 int union_lookup __P((void *)); 94 int union_create __P((void *)); 95 int union_whiteout __P((void *)); 96 int union_mknod __P((void *)); 97 int union_open __P((void *)); 98 int union_close __P((void *)); 99 int union_access __P((void *)); 100 int union_getattr __P((void *)); 101 int union_setattr __P((void *)); 102 int union_read __P((void *)); 103 int union_write __P((void *)); 104 int union_lease __P((void *)); 105 int union_ioctl __P((void *)); 106 int union_poll __P((void *)); 107 int union_revoke __P((void *)); 108 int union_mmap __P((void *)); 109 int union_fsync __P((void *)); 110 int union_seek __P((void *)); 111 int union_remove __P((void *)); 112 int union_link __P((void *)); 113 int union_rename __P((void *)); 114 int union_mkdir __P((void *)); 115 int union_rmdir __P((void *)); 116 int union_symlink __P((void *)); 117 int union_readdir __P((void *)); 118 int union_readlink __P((void *)); 119 int union_abortop __P((void *)); 120 int union_inactive __P((void *)); 121 int union_reclaim __P((void *)); 122 int union_lock __P((void *)); 123 int union_unlock __P((void *)); 124 int union_bmap __P((void *)); 125 int union_print __P((void *)); 126 int union_islocked __P((void *)); 127 int union_pathconf __P((void *)); 128 int union_advlock __P((void *)); 129 int union_strategy __P((void *)); 130 int union_getpages __P((void *)); 131 int union_putpages __P((void *)); 132 int union_kqfilter __P((void *)); 133 134 static void union_fixup __P((struct union_node *)); 135 static int union_lookup1 __P((struct vnode *, struct vnode **, 136 struct vnode **, struct componentname *)); 137 138 139 /* 140 * Global vfs data structures 141 */ 142 int (**union_vnodeop_p) __P((void *)); 143 const struct vnodeopv_entry_desc union_vnodeop_entries[] = { 144 { &vop_default_desc, vn_default_error }, 145 { &vop_lookup_desc, union_lookup }, /* lookup */ 146 { &vop_create_desc, union_create }, /* create */ 147 { &vop_whiteout_desc, union_whiteout }, /* whiteout */ 148 { &vop_mknod_desc, union_mknod }, /* mknod */ 149 { &vop_open_desc, union_open }, /* open */ 150 { &vop_close_desc, union_close }, /* close */ 151 { &vop_access_desc, union_access }, /* access */ 152 { &vop_getattr_desc, union_getattr }, /* getattr */ 153 { &vop_setattr_desc, union_setattr }, /* setattr */ 154 { &vop_read_desc, union_read }, /* read */ 155 { &vop_write_desc, union_write }, /* write */ 156 { &vop_lease_desc, union_lease }, /* lease */ 157 { &vop_ioctl_desc, union_ioctl }, /* ioctl */ 158 { &vop_poll_desc, union_poll }, /* select */ 159 { &vop_revoke_desc, union_revoke }, /* revoke */ 160 { &vop_mmap_desc, union_mmap }, /* mmap */ 161 { &vop_fsync_desc, union_fsync }, /* fsync */ 162 { &vop_seek_desc, union_seek }, /* seek */ 163 { &vop_remove_desc, union_remove }, /* remove */ 164 { &vop_link_desc, union_link }, /* link */ 165 { &vop_rename_desc, union_rename }, /* rename */ 166 { &vop_mkdir_desc, union_mkdir }, /* mkdir */ 167 { &vop_rmdir_desc, union_rmdir }, /* rmdir */ 168 { &vop_symlink_desc, union_symlink }, /* symlink */ 169 { &vop_readdir_desc, union_readdir }, /* readdir */ 170 { &vop_readlink_desc, union_readlink }, /* readlink */ 171 { &vop_abortop_desc, union_abortop }, /* abortop */ 172 { &vop_inactive_desc, union_inactive }, /* inactive */ 173 { &vop_reclaim_desc, union_reclaim }, /* reclaim */ 174 { &vop_lock_desc, union_lock }, /* lock */ 175 { &vop_unlock_desc, union_unlock }, /* unlock */ 176 { &vop_bmap_desc, union_bmap }, /* bmap */ 177 { &vop_strategy_desc, union_strategy }, /* strategy */ 178 { &vop_print_desc, union_print }, /* print */ 179 { &vop_islocked_desc, union_islocked }, /* islocked */ 180 { &vop_pathconf_desc, union_pathconf }, /* pathconf */ 181 { &vop_advlock_desc, union_advlock }, /* advlock */ 182 { &vop_getpages_desc, union_getpages }, /* getpages */ 183 { &vop_putpages_desc, union_putpages }, /* putpages */ 184 { &vop_kqfilter_desc, union_kqfilter }, /* kqfilter */ 185 #ifdef notdef 186 { &vop_blkatoff_desc, union_blkatoff }, /* blkatoff */ 187 { &vop_valloc_desc, union_valloc }, /* valloc */ 188 { &vop_vfree_desc, union_vfree }, /* vfree */ 189 { &vop_truncate_desc, union_truncate }, /* truncate */ 190 { &vop_update_desc, union_update }, /* update */ 191 { &vop_bwrite_desc, union_bwrite }, /* bwrite */ 192 #endif 193 { NULL, NULL } 194 }; 195 const struct vnodeopv_desc union_vnodeop_opv_desc = 196 { &union_vnodeop_p, union_vnodeop_entries }; 197 198 #define FIXUP(un) { \ 199 if (((un)->un_flags & UN_ULOCK) == 0) { \ 200 union_fixup(un); \ 201 } \ 202 } 203 204 static void 205 union_fixup(un) 206 struct union_node *un; 207 { 208 209 vn_lock(un->un_uppervp, LK_EXCLUSIVE | LK_RETRY); 210 un->un_flags |= UN_ULOCK; 211 } 212 213 static int 214 union_lookup1(udvp, dvpp, vpp, cnp) 215 struct vnode *udvp; 216 struct vnode **dvpp; 217 struct vnode **vpp; 218 struct componentname *cnp; 219 { 220 int error; 221 struct vnode *tdvp; 222 struct vnode *dvp; 223 struct mount *mp; 224 225 dvp = *dvpp; 226 227 /* 228 * If stepping up the directory tree, check for going 229 * back across the mount point, in which case do what 230 * lookup would do by stepping back down the mount 231 * hierarchy. 232 */ 233 if (cnp->cn_flags & ISDOTDOT) { 234 while ((dvp != udvp) && (dvp->v_flag & VROOT)) { 235 /* 236 * Don't do the NOCROSSMOUNT check 237 * at this level. By definition, 238 * union fs deals with namespaces, not 239 * filesystems. 240 */ 241 tdvp = dvp; 242 *dvpp = dvp = dvp->v_mount->mnt_vnodecovered; 243 vput(tdvp); 244 VREF(dvp); 245 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 246 } 247 } 248 249 error = VOP_LOOKUP(dvp, &tdvp, cnp); 250 if (error) 251 return (error); 252 253 /* 254 * The parent directory will have been unlocked, unless lookup 255 * found the last component. In which case, re-lock the node 256 * here to allow it to be unlocked again (phew) in union_lookup. 257 */ 258 if (dvp != tdvp && !(cnp->cn_flags & ISLASTCN)) 259 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 260 261 dvp = tdvp; 262 263 /* 264 * Lastly check if the current node is a mount point in 265 * which case walk up the mount hierarchy making sure not to 266 * bump into the root of the mount tree (ie. dvp != udvp). 267 */ 268 while (dvp != udvp && (dvp->v_type == VDIR) && 269 (mp = dvp->v_mountedhere)) { 270 271 if (vfs_busy(mp, 0, 0)) 272 continue; 273 274 error = VFS_ROOT(mp, &tdvp); 275 vfs_unbusy(mp); 276 if (error) { 277 vput(dvp); 278 return (error); 279 } 280 281 vput(dvp); 282 dvp = tdvp; 283 } 284 285 *vpp = dvp; 286 return (0); 287 } 288 289 int 290 union_lookup(v) 291 void *v; 292 { 293 struct vop_lookup_args /* { 294 struct vnodeop_desc *a_desc; 295 struct vnode *a_dvp; 296 struct vnode **a_vpp; 297 struct componentname *a_cnp; 298 } */ *ap = v; 299 int error; 300 int uerror, lerror; 301 struct vnode *uppervp, *lowervp; 302 struct vnode *upperdvp, *lowerdvp; 303 struct vnode *dvp = ap->a_dvp; 304 struct union_node *dun = VTOUNION(dvp); 305 struct componentname *cnp = ap->a_cnp; 306 int lockparent = cnp->cn_flags & LOCKPARENT; 307 struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); 308 struct ucred *saved_cred = NULL; 309 int iswhiteout; 310 struct vattr va; 311 312 #ifdef notyet 313 if (cnp->cn_namelen == 3 && 314 cnp->cn_nameptr[2] == '.' && 315 cnp->cn_nameptr[1] == '.' && 316 cnp->cn_nameptr[0] == '.') { 317 dvp = *ap->a_vpp = LOWERVP(ap->a_dvp); 318 if (dvp == NULLVP) 319 return (ENOENT); 320 VREF(dvp); 321 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 322 if (!lockparent || !(cnp->cn_flags & ISLASTCN)) 323 VOP_UNLOCK(ap->a_dvp, 0); 324 return (0); 325 } 326 #endif 327 328 if ((cnp->cn_flags & ISLASTCN) && 329 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 330 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 331 return (EROFS); 332 333 cnp->cn_flags |= LOCKPARENT; 334 335 upperdvp = dun->un_uppervp; 336 lowerdvp = dun->un_lowervp; 337 uppervp = NULLVP; 338 lowervp = NULLVP; 339 iswhiteout = 0; 340 341 /* 342 * do the lookup in the upper level. 343 * if that level comsumes additional pathnames, 344 * then assume that something special is going 345 * on and just return that vnode. 346 */ 347 if (upperdvp != NULLVP) { 348 FIXUP(dun); 349 /* 350 * If we're doing `..' in the underlying filesystem, 351 * we must drop our lock on the union node before 352 * going up the tree in the lower file system--if we block 353 * on the lowervp lock, and that's held by someone else 354 * coming down the tree and who's waiting for our lock, 355 * we would be hosed. 356 */ 357 if (cnp->cn_flags & ISDOTDOT) { 358 /* retain lock on underlying VP */ 359 dun->un_flags |= UN_KLOCK; 360 VOP_UNLOCK(dvp, 0); 361 } 362 uerror = union_lookup1(um->um_uppervp, &upperdvp, 363 &uppervp, cnp); 364 365 if (cnp->cn_flags & ISDOTDOT) { 366 if (dun->un_uppervp == upperdvp) { 367 /* 368 * we got the underlying bugger back locked... 369 * now take back the union node lock. Since we 370 * hold the uppervp lock, we can diddle union 371 * locking flags at will. :) 372 */ 373 dun->un_flags |= UN_ULOCK; 374 } 375 /* 376 * if upperdvp got swapped out, it means we did 377 * some mount point magic, and we do not have 378 * dun->un_uppervp locked currently--so we get it 379 * locked here (don't set the UN_ULOCK flag). 380 */ 381 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 382 } 383 if (cnp->cn_consume != 0) { 384 *ap->a_vpp = uppervp; 385 if (!lockparent) 386 cnp->cn_flags &= ~LOCKPARENT; 387 return (uerror); 388 } 389 if (uerror == ENOENT || uerror == EJUSTRETURN) { 390 if (cnp->cn_flags & ISWHITEOUT) { 391 iswhiteout = 1; 392 } else if (lowerdvp != NULLVP) { 393 lerror = VOP_GETATTR(upperdvp, &va, 394 cnp->cn_cred, cnp->cn_proc); 395 if (lerror == 0 && (va.va_flags & OPAQUE)) 396 iswhiteout = 1; 397 } 398 } 399 } else { 400 uerror = ENOENT; 401 } 402 403 /* 404 * in a similar way to the upper layer, do the lookup 405 * in the lower layer. this time, if there is some 406 * component magic going on, then vput whatever we got 407 * back from the upper layer and return the lower vnode 408 * instead. 409 */ 410 if (lowerdvp != NULLVP && !iswhiteout) { 411 int nameiop; 412 413 vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY); 414 415 /* 416 * Only do a LOOKUP on the bottom node, since 417 * we won't be making changes to it anyway. 418 */ 419 nameiop = cnp->cn_nameiop; 420 cnp->cn_nameiop = LOOKUP; 421 if (um->um_op == UNMNT_BELOW) { 422 saved_cred = cnp->cn_cred; 423 cnp->cn_cred = um->um_cred; 424 } 425 /* 426 * we shouldn't have to worry about locking interactions 427 * between the lower layer and our union layer (w.r.t. 428 * `..' processing) because we don't futz with lowervp 429 * locks in the union-node instantiation code path. 430 */ 431 lerror = union_lookup1(um->um_lowervp, &lowerdvp, 432 &lowervp, cnp); 433 if (um->um_op == UNMNT_BELOW) 434 cnp->cn_cred = saved_cred; 435 cnp->cn_nameiop = nameiop; 436 437 if (lowervp != lowerdvp) 438 VOP_UNLOCK(lowerdvp, 0); 439 440 if (cnp->cn_consume != 0) { 441 if (uppervp != NULLVP) { 442 if (uppervp == upperdvp) 443 vrele(uppervp); 444 else 445 vput(uppervp); 446 uppervp = NULLVP; 447 } 448 *ap->a_vpp = lowervp; 449 if (!lockparent) 450 cnp->cn_flags &= ~LOCKPARENT; 451 return (lerror); 452 } 453 } else { 454 lerror = ENOENT; 455 if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) { 456 lowervp = LOWERVP(dun->un_pvp); 457 if (lowervp != NULLVP) { 458 VREF(lowervp); 459 vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY); 460 lerror = 0; 461 } 462 } 463 } 464 465 if (!lockparent) 466 cnp->cn_flags &= ~LOCKPARENT; 467 468 /* 469 * EJUSTRETURN is used by underlying filesystems to indicate that 470 * a directory modification op was started successfully. 471 * This will only happen in the upper layer, since 472 * the lower layer only does LOOKUPs. 473 * If this union is mounted read-only, bounce it now. 474 */ 475 476 if ((uerror == EJUSTRETURN) && (cnp->cn_flags & ISLASTCN) && 477 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 478 ((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME))) 479 uerror = EROFS; 480 481 /* 482 * at this point, we have uerror and lerror indicating 483 * possible errors with the lookups in the upper and lower 484 * layers. additionally, uppervp and lowervp are (locked) 485 * references to existing vnodes in the upper and lower layers. 486 * 487 * there are now three cases to consider. 488 * 1. if both layers returned an error, then return whatever 489 * error the upper layer generated. 490 * 491 * 2. if the top layer failed and the bottom layer succeeded 492 * then two subcases occur. 493 * a. the bottom vnode is not a directory, in which 494 * case just return a new union vnode referencing 495 * an empty top layer and the existing bottom layer. 496 * b. the bottom vnode is a directory, in which case 497 * create a new directory in the top-level and 498 * continue as in case 3. 499 * 500 * 3. if the top layer succeeded then return a new union 501 * vnode referencing whatever the new top layer and 502 * whatever the bottom layer returned. 503 */ 504 505 *ap->a_vpp = NULLVP; 506 507 508 /* case 1. */ 509 if ((uerror != 0) && (lerror != 0)) { 510 return (uerror); 511 } 512 513 /* case 2. */ 514 if (uerror != 0 /* && (lerror == 0) */ ) { 515 if (lowervp->v_type == VDIR) { /* case 2b. */ 516 /* 517 * We may be racing another process to make the 518 * upper-level shadow directory. Be careful with 519 * locks/etc! 520 */ 521 dun->un_flags &= ~UN_ULOCK; 522 VOP_UNLOCK(upperdvp, 0); 523 uerror = union_mkshadow(um, upperdvp, cnp, &uppervp); 524 vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY); 525 dun->un_flags |= UN_ULOCK; 526 527 if (uerror) { 528 if (lowervp != NULLVP) { 529 vput(lowervp); 530 lowervp = NULLVP; 531 } 532 return (uerror); 533 } 534 } 535 } 536 537 if (lowervp != NULLVP) 538 VOP_UNLOCK(lowervp, 0); 539 540 error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, 541 uppervp, lowervp, 1); 542 543 if (error) { 544 if (uppervp != NULLVP) 545 vput(uppervp); 546 if (lowervp != NULLVP) 547 vrele(lowervp); 548 } else { 549 if (*ap->a_vpp != dvp) 550 if (!lockparent || !(cnp->cn_flags & ISLASTCN)) 551 VOP_UNLOCK(dvp, 0); 552 if (cnp->cn_namelen == 1 && 553 cnp->cn_nameptr[0] == '.' && 554 *ap->a_vpp != dvp) { 555 panic("union_lookup -> . (%p) != startdir (%p)", 556 ap->a_vpp, dvp); 557 } 558 } 559 560 return (error); 561 } 562 563 int 564 union_create(v) 565 void *v; 566 { 567 struct vop_create_args /* { 568 struct vnode *a_dvp; 569 struct vnode **a_vpp; 570 struct componentname *a_cnp; 571 struct vattr *a_vap; 572 } */ *ap = v; 573 struct union_node *un = VTOUNION(ap->a_dvp); 574 struct vnode *dvp = un->un_uppervp; 575 struct componentname *cnp = ap->a_cnp; 576 577 if (dvp != NULLVP) { 578 int error; 579 struct vnode *vp; 580 struct mount *mp; 581 582 FIXUP(un); 583 584 VREF(dvp); 585 un->un_flags |= UN_KLOCK; 586 mp = ap->a_dvp->v_mount; 587 vput(ap->a_dvp); 588 error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap); 589 if (error) 590 return (error); 591 592 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp, 593 NULLVP, 1); 594 if (error) 595 vput(vp); 596 return (error); 597 } 598 599 vput(ap->a_dvp); 600 return (EROFS); 601 } 602 603 int 604 union_whiteout(v) 605 void *v; 606 { 607 struct vop_whiteout_args /* { 608 struct vnode *a_dvp; 609 struct componentname *a_cnp; 610 int a_flags; 611 } */ *ap = v; 612 struct union_node *un = VTOUNION(ap->a_dvp); 613 struct componentname *cnp = ap->a_cnp; 614 615 if (un->un_uppervp == NULLVP) 616 return (EOPNOTSUPP); 617 618 FIXUP(un); 619 return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags)); 620 } 621 622 int 623 union_mknod(v) 624 void *v; 625 { 626 struct vop_mknod_args /* { 627 struct vnode *a_dvp; 628 struct vnode **a_vpp; 629 struct componentname *a_cnp; 630 struct vattr *a_vap; 631 } */ *ap = v; 632 struct union_node *un = VTOUNION(ap->a_dvp); 633 struct vnode *dvp = un->un_uppervp; 634 struct componentname *cnp = ap->a_cnp; 635 636 if (dvp != NULLVP) { 637 int error; 638 struct vnode *vp; 639 struct mount *mp; 640 641 FIXUP(un); 642 643 VREF(dvp); 644 un->un_flags |= UN_KLOCK; 645 mp = ap->a_dvp->v_mount; 646 vput(ap->a_dvp); 647 error = VOP_MKNOD(dvp, &vp, cnp, ap->a_vap); 648 if (error) 649 return (error); 650 651 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, 652 cnp, vp, NULLVP, 1); 653 if (error) 654 vput(vp); 655 return (error); 656 } 657 658 vput(ap->a_dvp); 659 return (EROFS); 660 } 661 662 int 663 union_open(v) 664 void *v; 665 { 666 struct vop_open_args /* { 667 struct vnodeop_desc *a_desc; 668 struct vnode *a_vp; 669 int a_mode; 670 struct ucred *a_cred; 671 struct proc *a_p; 672 } */ *ap = v; 673 struct union_node *un = VTOUNION(ap->a_vp); 674 struct vnode *tvp; 675 int mode = ap->a_mode; 676 struct ucred *cred = ap->a_cred; 677 struct proc *p = ap->a_p; 678 int error; 679 680 /* 681 * If there is an existing upper vp then simply open that. 682 */ 683 tvp = un->un_uppervp; 684 if (tvp == NULLVP) { 685 /* 686 * If the lower vnode is being opened for writing, then 687 * copy the file contents to the upper vnode and open that, 688 * otherwise can simply open the lower vnode. 689 */ 690 tvp = un->un_lowervp; 691 if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) { 692 error = union_copyup(un, (mode&O_TRUNC) == 0, cred, p); 693 if (error == 0) 694 error = VOP_OPEN(un->un_uppervp, mode, cred, p); 695 return (error); 696 } 697 698 /* 699 * Just open the lower vnode, but check for nodev mount flag 700 */ 701 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 702 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 703 return ENXIO; 704 un->un_openl++; 705 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); 706 error = VOP_OPEN(tvp, mode, cred, p); 707 VOP_UNLOCK(tvp, 0); 708 709 return (error); 710 } 711 /* 712 * Just open the upper vnode, checking for nodev mount flag first 713 */ 714 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 715 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 716 return ENXIO; 717 718 FIXUP(un); 719 720 error = VOP_OPEN(tvp, mode, cred, p); 721 722 return (error); 723 } 724 725 int 726 union_close(v) 727 void *v; 728 { 729 struct vop_close_args /* { 730 struct vnode *a_vp; 731 int a_fflag; 732 struct ucred *a_cred; 733 struct proc *a_p; 734 } */ *ap = v; 735 struct union_node *un = VTOUNION(ap->a_vp); 736 struct vnode *vp; 737 738 vp = un->un_uppervp; 739 if (vp == NULLVP) { 740 #ifdef UNION_DIAGNOSTIC 741 if (un->un_openl <= 0) 742 panic("union: un_openl cnt"); 743 #endif 744 --un->un_openl; 745 vp = un->un_lowervp; 746 } 747 748 #ifdef DIAGNOSTIC 749 if (vp == NULLVP) { 750 vprint("empty union vnode", vp); 751 panic("union_close empty vnode"); 752 } 753 #endif 754 755 ap->a_vp = vp; 756 return (VCALL(vp, VOFFSET(vop_close), ap)); 757 } 758 759 /* 760 * Check access permission on the union vnode. 761 * The access check being enforced is to check 762 * against both the underlying vnode, and any 763 * copied vnode. This ensures that no additional 764 * file permissions are given away simply because 765 * the user caused an implicit file copy. 766 */ 767 int 768 union_access(v) 769 void *v; 770 { 771 struct vop_access_args /* { 772 struct vnodeop_desc *a_desc; 773 struct vnode *a_vp; 774 int a_mode; 775 struct ucred *a_cred; 776 struct proc *a_p; 777 } */ *ap = v; 778 struct vnode *vp = ap->a_vp; 779 struct union_node *un = VTOUNION(vp); 780 int error = EACCES; 781 struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount); 782 783 /* 784 * Disallow write attempts on read-only file systems; 785 * unless the file is a socket, fifo, or a block or 786 * character device resident on the file system. 787 */ 788 if (ap->a_mode & VWRITE) { 789 switch (vp->v_type) { 790 case VDIR: 791 case VLNK: 792 case VREG: 793 if (vp->v_mount->mnt_flag & MNT_RDONLY) 794 return (EROFS); 795 break; 796 case VBAD: 797 case VBLK: 798 case VCHR: 799 case VSOCK: 800 case VFIFO: 801 case VNON: 802 default: 803 break; 804 } 805 } 806 807 808 if ((vp = un->un_uppervp) != NULLVP) { 809 FIXUP(un); 810 ap->a_vp = vp; 811 return (VCALL(vp, VOFFSET(vop_access), ap)); 812 } 813 814 if ((vp = un->un_lowervp) != NULLVP) { 815 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 816 ap->a_vp = vp; 817 error = VCALL(vp, VOFFSET(vop_access), ap); 818 if (error == 0) { 819 if (um->um_op == UNMNT_BELOW) { 820 ap->a_cred = um->um_cred; 821 error = VCALL(vp, VOFFSET(vop_access), ap); 822 } 823 } 824 VOP_UNLOCK(vp, 0); 825 if (error) 826 return (error); 827 } 828 829 return (error); 830 } 831 832 /* 833 * We handle getattr only to change the fsid and 834 * track object sizes 835 */ 836 int 837 union_getattr(v) 838 void *v; 839 { 840 struct vop_getattr_args /* { 841 struct vnode *a_vp; 842 struct vattr *a_vap; 843 struct ucred *a_cred; 844 struct proc *a_p; 845 } */ *ap = v; 846 int error; 847 struct union_node *un = VTOUNION(ap->a_vp); 848 struct vnode *vp = un->un_uppervp; 849 struct vattr *vap; 850 struct vattr va; 851 852 853 /* 854 * Some programs walk the filesystem hierarchy by counting 855 * links to directories to avoid stat'ing all the time. 856 * This means the link count on directories needs to be "correct". 857 * The only way to do that is to call getattr on both layers 858 * and fix up the link count. The link count will not necessarily 859 * be accurate but will be large enough to defeat the tree walkers. 860 * 861 * To make life more interesting, some filesystems don't keep 862 * track of link counts in the expected way, and return a 863 * link count of `1' for those directories; if either of the 864 * component directories returns a link count of `1', we return a 1. 865 */ 866 867 vap = ap->a_vap; 868 869 vp = un->un_uppervp; 870 if (vp != NULLVP) { 871 /* 872 * It's not clear whether VOP_GETATTR is to be 873 * called with the vnode locked or not. stat() calls 874 * it with (vp) locked, and fstat calls it with 875 * (vp) unlocked. 876 * In the mean time, compensate here by checking 877 * the union_node's lock flag. 878 */ 879 if (un->un_flags & UN_LOCKED) 880 FIXUP(un); 881 882 error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); 883 if (error) 884 return (error); 885 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 886 } 887 888 if (vp == NULLVP) { 889 vp = un->un_lowervp; 890 } else if (vp->v_type == VDIR) { 891 vp = un->un_lowervp; 892 if (vp != NULLVP) 893 vap = &va; 894 } else { 895 vp = NULLVP; 896 } 897 898 if (vp != NULLVP) { 899 error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); 900 if (error) 901 return (error); 902 union_newsize(ap->a_vp, VNOVAL, vap->va_size); 903 } 904 905 if ((vap != ap->a_vap) && (vap->va_type == VDIR)) { 906 /* 907 * Link count manipulation: 908 * - If both return "2", return 2 (no subdirs) 909 * - If one or the other return "1", return "1" (ENOCLUE) 910 */ 911 if ((ap->a_vap->va_nlink == 2) && 912 (vap->va_nlink == 2)) 913 ; 914 else if (ap->a_vap->va_nlink != 1) { 915 if (vap->va_nlink == 1) 916 ap->a_vap->va_nlink = 1; 917 else 918 ap->a_vap->va_nlink += vap->va_nlink; 919 } 920 } 921 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0]; 922 return (0); 923 } 924 925 int 926 union_setattr(v) 927 void *v; 928 { 929 struct vop_setattr_args /* { 930 struct vnode *a_vp; 931 struct vattr *a_vap; 932 struct ucred *a_cred; 933 struct proc *a_p; 934 } */ *ap = v; 935 struct vattr *vap = ap->a_vap; 936 struct vnode *vp = ap->a_vp; 937 struct union_node *un = VTOUNION(vp); 938 int error; 939 940 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL || 941 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL || 942 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) && 943 (vp->v_mount->mnt_flag & MNT_RDONLY)) 944 return (EROFS); 945 if (vap->va_size != VNOVAL) { 946 switch (vp->v_type) { 947 case VDIR: 948 return (EISDIR); 949 case VCHR: 950 case VBLK: 951 case VSOCK: 952 case VFIFO: 953 break; 954 case VREG: 955 case VLNK: 956 default: 957 /* 958 * Disallow write attempts if the filesystem is 959 * mounted read-only. 960 */ 961 if (vp->v_mount->mnt_flag & MNT_RDONLY) 962 return (EROFS); 963 } 964 } 965 966 /* 967 * Handle case of truncating lower object to zero size, 968 * by creating a zero length upper object. This is to 969 * handle the case of open with O_TRUNC and O_CREAT. 970 */ 971 if ((un->un_uppervp == NULLVP) && 972 /* assert(un->un_lowervp != NULLVP) */ 973 (un->un_lowervp->v_type == VREG)) { 974 error = union_copyup(un, (vap->va_size != 0), 975 ap->a_cred, ap->a_p); 976 if (error) 977 return (error); 978 } 979 980 /* 981 * Try to set attributes in upper layer, 982 * otherwise return read-only filesystem error. 983 */ 984 if (un->un_uppervp != NULLVP) { 985 FIXUP(un); 986 error = VOP_SETATTR(un->un_uppervp, vap, 987 ap->a_cred, ap->a_p); 988 if ((error == 0) && (vap->va_size != VNOVAL)) 989 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 990 } else { 991 error = EROFS; 992 } 993 994 return (error); 995 } 996 997 int 998 union_read(v) 999 void *v; 1000 { 1001 struct vop_read_args /* { 1002 struct vnode *a_vp; 1003 struct uio *a_uio; 1004 int a_ioflag; 1005 struct ucred *a_cred; 1006 } */ *ap = v; 1007 int error; 1008 struct vnode *vp = OTHERVP(ap->a_vp); 1009 int dolock = (vp == LOWERVP(ap->a_vp)); 1010 1011 if (dolock) 1012 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1013 else 1014 FIXUP(VTOUNION(ap->a_vp)); 1015 error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 1016 if (dolock) 1017 VOP_UNLOCK(vp, 0); 1018 1019 /* 1020 * XXX 1021 * perhaps the size of the underlying object has changed under 1022 * our feet. take advantage of the offset information present 1023 * in the uio structure. 1024 */ 1025 if (error == 0) { 1026 struct union_node *un = VTOUNION(ap->a_vp); 1027 off_t cur = ap->a_uio->uio_offset; 1028 1029 if (vp == un->un_uppervp) { 1030 if (cur > un->un_uppersz) 1031 union_newsize(ap->a_vp, cur, VNOVAL); 1032 } else { 1033 if (cur > un->un_lowersz) 1034 union_newsize(ap->a_vp, VNOVAL, cur); 1035 } 1036 } 1037 1038 return (error); 1039 } 1040 1041 int 1042 union_write(v) 1043 void *v; 1044 { 1045 struct vop_read_args /* { 1046 struct vnode *a_vp; 1047 struct uio *a_uio; 1048 int a_ioflag; 1049 struct ucred *a_cred; 1050 } */ *ap = v; 1051 int error; 1052 struct vnode *vp; 1053 struct union_node *un = VTOUNION(ap->a_vp); 1054 1055 vp = UPPERVP(ap->a_vp); 1056 if (vp == NULLVP) 1057 panic("union: missing upper layer in write"); 1058 1059 FIXUP(un); 1060 error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 1061 1062 /* 1063 * the size of the underlying object may be changed by the 1064 * write. 1065 */ 1066 if (error == 0) { 1067 off_t cur = ap->a_uio->uio_offset; 1068 1069 if (cur > un->un_uppersz) 1070 union_newsize(ap->a_vp, cur, VNOVAL); 1071 } 1072 1073 return (error); 1074 } 1075 1076 int 1077 union_lease(v) 1078 void *v; 1079 { 1080 struct vop_lease_args /* { 1081 struct vnode *a_vp; 1082 struct proc *a_p; 1083 struct ucred *a_cred; 1084 int a_flag; 1085 } */ *ap = v; 1086 struct vnode *ovp = OTHERVP(ap->a_vp); 1087 1088 ap->a_vp = ovp; 1089 return (VCALL(ovp, VOFFSET(vop_lease), ap)); 1090 } 1091 1092 int 1093 union_ioctl(v) 1094 void *v; 1095 { 1096 struct vop_ioctl_args /* { 1097 struct vnode *a_vp; 1098 int a_command; 1099 caddr_t a_data; 1100 int a_fflag; 1101 struct ucred *a_cred; 1102 struct proc *a_p; 1103 } */ *ap = v; 1104 struct vnode *ovp = OTHERVP(ap->a_vp); 1105 1106 ap->a_vp = ovp; 1107 return (VCALL(ovp, VOFFSET(vop_ioctl), ap)); 1108 } 1109 1110 int 1111 union_poll(v) 1112 void *v; 1113 { 1114 struct vop_poll_args /* { 1115 struct vnode *a_vp; 1116 int a_events; 1117 struct proc *a_p; 1118 } */ *ap = v; 1119 struct vnode *ovp = OTHERVP(ap->a_vp); 1120 1121 ap->a_vp = ovp; 1122 return (VCALL(ovp, VOFFSET(vop_poll), ap)); 1123 } 1124 1125 int 1126 union_revoke(v) 1127 void *v; 1128 { 1129 struct vop_revoke_args /* { 1130 struct vnode *a_vp; 1131 int a_flags; 1132 struct proc *a_p; 1133 } */ *ap = v; 1134 struct vnode *vp = ap->a_vp; 1135 1136 if (UPPERVP(vp)) 1137 VOP_REVOKE(UPPERVP(vp), ap->a_flags); 1138 if (LOWERVP(vp)) 1139 VOP_REVOKE(LOWERVP(vp), ap->a_flags); 1140 vgone(vp); 1141 return (0); 1142 } 1143 1144 int 1145 union_mmap(v) 1146 void *v; 1147 { 1148 struct vop_mmap_args /* { 1149 struct vnode *a_vp; 1150 int a_fflags; 1151 struct ucred *a_cred; 1152 struct proc *a_p; 1153 } */ *ap = v; 1154 struct vnode *ovp = OTHERVP(ap->a_vp); 1155 1156 ap->a_vp = ovp; 1157 return (VCALL(ovp, VOFFSET(vop_mmap), ap)); 1158 } 1159 1160 int 1161 union_fsync(v) 1162 void *v; 1163 { 1164 struct vop_fsync_args /* { 1165 struct vnode *a_vp; 1166 struct ucred *a_cred; 1167 int a_flags; 1168 off_t offhi; 1169 off_t offlo; 1170 struct proc *a_p; 1171 } */ *ap = v; 1172 int error = 0; 1173 struct proc *p; 1174 struct vnode *targetvp; 1175 1176 /* 1177 * If vinvalbuf is calling us, it's a "shallow fsync" -- don't 1178 * bother syncing the underlying vnodes, since (a) they'll be 1179 * fsync'ed when reclaimed and (b) we could deadlock if 1180 * they're locked; otherwise, pass it through to the 1181 * underlying layer. 1182 */ 1183 if (ap->a_flags & FSYNC_RECLAIM) 1184 return 0; 1185 1186 targetvp = OTHERVP(ap->a_vp); 1187 p = ap->a_p; 1188 1189 if (targetvp != NULLVP) { 1190 int dolock = (targetvp == LOWERVP(ap->a_vp)); 1191 1192 if (dolock) 1193 vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY); 1194 else 1195 FIXUP(VTOUNION(ap->a_vp)); 1196 error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags, 1197 ap->a_offlo, ap->a_offhi, p); 1198 if (dolock) 1199 VOP_UNLOCK(targetvp, 0); 1200 } 1201 1202 return (error); 1203 } 1204 1205 int 1206 union_seek(v) 1207 void *v; 1208 { 1209 struct vop_seek_args /* { 1210 struct vnode *a_vp; 1211 off_t a_oldoff; 1212 off_t a_newoff; 1213 struct ucred *a_cred; 1214 } */ *ap = v; 1215 struct vnode *ovp = OTHERVP(ap->a_vp); 1216 1217 ap->a_vp = ovp; 1218 return (VCALL(ovp, VOFFSET(vop_seek), ap)); 1219 } 1220 1221 int 1222 union_remove(v) 1223 void *v; 1224 { 1225 struct vop_remove_args /* { 1226 struct vnode *a_dvp; 1227 struct vnode *a_vp; 1228 struct componentname *a_cnp; 1229 } */ *ap = v; 1230 int error; 1231 struct union_node *dun = VTOUNION(ap->a_dvp); 1232 struct union_node *un = VTOUNION(ap->a_vp); 1233 struct componentname *cnp = ap->a_cnp; 1234 1235 if (dun->un_uppervp == NULLVP) 1236 panic("union remove: null upper vnode"); 1237 1238 if (un->un_uppervp != NULLVP) { 1239 struct vnode *dvp = dun->un_uppervp; 1240 struct vnode *vp = un->un_uppervp; 1241 1242 FIXUP(dun); 1243 VREF(dvp); 1244 dun->un_flags |= UN_KLOCK; 1245 vput(ap->a_dvp); 1246 FIXUP(un); 1247 VREF(vp); 1248 un->un_flags |= UN_KLOCK; 1249 vput(ap->a_vp); 1250 1251 if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_proc)) 1252 cnp->cn_flags |= DOWHITEOUT; 1253 error = VOP_REMOVE(dvp, vp, cnp); 1254 if (!error) 1255 union_removed_upper(un); 1256 } else { 1257 FIXUP(dun); 1258 error = union_mkwhiteout( 1259 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1260 dun->un_uppervp, ap->a_cnp, un->un_path); 1261 vput(ap->a_dvp); 1262 vput(ap->a_vp); 1263 } 1264 1265 return (error); 1266 } 1267 1268 int 1269 union_link(v) 1270 void *v; 1271 { 1272 struct vop_link_args /* { 1273 struct vnode *a_dvp; 1274 struct vnode *a_vp; 1275 struct componentname *a_cnp; 1276 } */ *ap = v; 1277 int error = 0; 1278 struct componentname *cnp = ap->a_cnp; 1279 struct proc *p = cnp->cn_proc; 1280 struct union_node *dun; 1281 struct vnode *vp; 1282 struct vnode *dvp; 1283 1284 dun = VTOUNION(ap->a_dvp); 1285 1286 #ifdef DIAGNOSTIC 1287 if (!(ap->a_cnp->cn_flags & LOCKPARENT)) { 1288 printf("union_link called without LOCKPARENT set!\n"); 1289 error = EIO; /* need some error code for "caller is a bozo" */ 1290 } else 1291 #endif 1292 1293 1294 if (ap->a_dvp->v_op != ap->a_vp->v_op) { 1295 vp = ap->a_vp; 1296 } else { 1297 struct union_node *un = VTOUNION(ap->a_vp); 1298 if (un->un_uppervp == NULLVP) { 1299 /* 1300 * Needs to be copied before we can link it. 1301 */ 1302 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY); 1303 if (dun->un_uppervp == un->un_dirvp) { 1304 dun->un_flags &= ~UN_ULOCK; 1305 VOP_UNLOCK(dun->un_uppervp, 0); 1306 } 1307 error = union_copyup(un, 1, cnp->cn_cred, p); 1308 if (dun->un_uppervp == un->un_dirvp) { 1309 /* 1310 * During copyup, we dropped the lock on the 1311 * dir and invalidated any saved namei lookup 1312 * state for the directory we'll be entering 1313 * the link in. We need to re-run the lookup 1314 * in that directory to reset any state needed 1315 * for VOP_LINK. 1316 * Call relookup on the union-layer to reset 1317 * the state. 1318 */ 1319 vp = NULLVP; 1320 if (dun->un_uppervp == NULLVP) 1321 panic("union: null upperdvp?"); 1322 /* 1323 * relookup starts with an unlocked node, 1324 * and since LOCKPARENT is set returns 1325 * the starting directory locked. 1326 */ 1327 VOP_UNLOCK(ap->a_dvp, 0); 1328 error = relookup(ap->a_dvp, &vp, ap->a_cnp); 1329 if (error) { 1330 vrele(ap->a_dvp); 1331 VOP_UNLOCK(ap->a_vp, 0); 1332 return EROFS; /* ? */ 1333 } 1334 if (vp != NULLVP) { 1335 /* 1336 * The name we want to create has 1337 * mysteriously appeared (a race?) 1338 */ 1339 error = EEXIST; 1340 VOP_UNLOCK(ap->a_vp, 0); 1341 goto croak; 1342 } 1343 } 1344 VOP_UNLOCK(ap->a_vp, 0); 1345 } 1346 vp = un->un_uppervp; 1347 } 1348 1349 dvp = dun->un_uppervp; 1350 if (dvp == NULLVP) 1351 error = EROFS; 1352 1353 if (error) { 1354 croak: 1355 vput(ap->a_dvp); 1356 return (error); 1357 } 1358 1359 FIXUP(dun); 1360 VREF(dvp); 1361 dun->un_flags |= UN_KLOCK; 1362 vput(ap->a_dvp); 1363 1364 return (VOP_LINK(dvp, vp, cnp)); 1365 } 1366 1367 int 1368 union_rename(v) 1369 void *v; 1370 { 1371 struct vop_rename_args /* { 1372 struct vnode *a_fdvp; 1373 struct vnode *a_fvp; 1374 struct componentname *a_fcnp; 1375 struct vnode *a_tdvp; 1376 struct vnode *a_tvp; 1377 struct componentname *a_tcnp; 1378 } */ *ap = v; 1379 int error; 1380 1381 struct vnode *fdvp = ap->a_fdvp; 1382 struct vnode *fvp = ap->a_fvp; 1383 struct vnode *tdvp = ap->a_tdvp; 1384 struct vnode *tvp = ap->a_tvp; 1385 1386 if (fdvp->v_op == union_vnodeop_p) { /* always true */ 1387 struct union_node *un = VTOUNION(fdvp); 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 fdvp = un->un_uppervp; 1400 VREF(fdvp); 1401 vrele(ap->a_fdvp); 1402 } 1403 1404 if (fvp->v_op == union_vnodeop_p) { /* always true */ 1405 struct union_node *un = VTOUNION(fvp); 1406 if (un->un_uppervp == NULLVP) { 1407 /* XXX: should do a copyup */ 1408 error = EXDEV; 1409 goto bad; 1410 } 1411 1412 if (un->un_lowervp != NULLVP) 1413 ap->a_fcnp->cn_flags |= DOWHITEOUT; 1414 1415 fvp = un->un_uppervp; 1416 VREF(fvp); 1417 vrele(ap->a_fvp); 1418 } 1419 1420 if (tdvp->v_op == union_vnodeop_p) { 1421 struct union_node *un = VTOUNION(tdvp); 1422 if (un->un_uppervp == NULLVP) { 1423 /* 1424 * this should never happen in normal 1425 * operation but might if there was 1426 * a problem creating the top-level shadow 1427 * directory. 1428 */ 1429 error = EXDEV; 1430 goto bad; 1431 } 1432 1433 tdvp = un->un_uppervp; 1434 VREF(tdvp); 1435 un->un_flags |= UN_KLOCK; 1436 vput(ap->a_tdvp); 1437 } 1438 1439 if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) { 1440 struct union_node *un = VTOUNION(tvp); 1441 1442 tvp = un->un_uppervp; 1443 if (tvp != NULLVP) { 1444 VREF(tvp); 1445 un->un_flags |= UN_KLOCK; 1446 } 1447 vput(ap->a_tvp); 1448 } 1449 1450 return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp)); 1451 1452 bad: 1453 vrele(fdvp); 1454 vrele(fvp); 1455 vput(tdvp); 1456 if (tvp != NULLVP) 1457 vput(tvp); 1458 1459 return (error); 1460 } 1461 1462 int 1463 union_mkdir(v) 1464 void *v; 1465 { 1466 struct vop_mkdir_args /* { 1467 struct vnode *a_dvp; 1468 struct vnode **a_vpp; 1469 struct componentname *a_cnp; 1470 struct vattr *a_vap; 1471 } */ *ap = v; 1472 struct union_node *un = VTOUNION(ap->a_dvp); 1473 struct vnode *dvp = un->un_uppervp; 1474 struct componentname *cnp = ap->a_cnp; 1475 1476 if (dvp != NULLVP) { 1477 int error; 1478 struct vnode *vp; 1479 1480 FIXUP(un); 1481 VREF(dvp); 1482 un->un_flags |= UN_KLOCK; 1483 VOP_UNLOCK(ap->a_dvp, 0); 1484 error = VOP_MKDIR(dvp, &vp, cnp, ap->a_vap); 1485 if (error) { 1486 vrele(ap->a_dvp); 1487 return (error); 1488 } 1489 1490 error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, 1491 NULLVP, cnp, vp, NULLVP, 1); 1492 vrele(ap->a_dvp); 1493 if (error) 1494 vput(vp); 1495 return (error); 1496 } 1497 1498 vput(ap->a_dvp); 1499 return (EROFS); 1500 } 1501 1502 int 1503 union_rmdir(v) 1504 void *v; 1505 { 1506 struct vop_rmdir_args /* { 1507 struct vnode *a_dvp; 1508 struct vnode *a_vp; 1509 struct componentname *a_cnp; 1510 } */ *ap = v; 1511 int error; 1512 struct union_node *dun = VTOUNION(ap->a_dvp); 1513 struct union_node *un = VTOUNION(ap->a_vp); 1514 struct componentname *cnp = ap->a_cnp; 1515 1516 if (dun->un_uppervp == NULLVP) 1517 panic("union rmdir: null upper vnode"); 1518 1519 if (un->un_uppervp != NULLVP) { 1520 struct vnode *dvp = dun->un_uppervp; 1521 struct vnode *vp = un->un_uppervp; 1522 1523 FIXUP(dun); 1524 VREF(dvp); 1525 dun->un_flags |= UN_KLOCK; 1526 vput(ap->a_dvp); 1527 FIXUP(un); 1528 VREF(vp); 1529 un->un_flags |= UN_KLOCK; 1530 vput(ap->a_vp); 1531 1532 if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_proc)) 1533 cnp->cn_flags |= DOWHITEOUT; 1534 error = VOP_RMDIR(dvp, vp, ap->a_cnp); 1535 if (!error) 1536 union_removed_upper(un); 1537 } else { 1538 FIXUP(dun); 1539 error = union_mkwhiteout( 1540 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1541 dun->un_uppervp, ap->a_cnp, un->un_path); 1542 vput(ap->a_dvp); 1543 vput(ap->a_vp); 1544 } 1545 1546 return (error); 1547 } 1548 1549 int 1550 union_symlink(v) 1551 void *v; 1552 { 1553 struct vop_symlink_args /* { 1554 struct vnode *a_dvp; 1555 struct vnode **a_vpp; 1556 struct componentname *a_cnp; 1557 struct vattr *a_vap; 1558 char *a_target; 1559 } */ *ap = v; 1560 struct union_node *un = VTOUNION(ap->a_dvp); 1561 struct vnode *dvp = un->un_uppervp; 1562 struct componentname *cnp = ap->a_cnp; 1563 1564 if (dvp != NULLVP) { 1565 int error; 1566 1567 FIXUP(un); 1568 VREF(dvp); 1569 un->un_flags |= UN_KLOCK; 1570 vput(ap->a_dvp); 1571 error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap, 1572 ap->a_target); 1573 return (error); 1574 } 1575 1576 vput(ap->a_dvp); 1577 return (EROFS); 1578 } 1579 1580 /* 1581 * union_readdir works in concert with getdirentries and 1582 * readdir(3) to provide a list of entries in the unioned 1583 * directories. getdirentries is responsible for walking 1584 * down the union stack. readdir(3) is responsible for 1585 * eliminating duplicate names from the returned data stream. 1586 */ 1587 int 1588 union_readdir(v) 1589 void *v; 1590 { 1591 struct vop_readdir_args /* { 1592 struct vnodeop_desc *a_desc; 1593 struct vnode *a_vp; 1594 struct uio *a_uio; 1595 struct ucred *a_cred; 1596 int *a_eofflag; 1597 u_long *a_cookies; 1598 int a_ncookies; 1599 } */ *ap = v; 1600 struct union_node *un = VTOUNION(ap->a_vp); 1601 struct vnode *uvp = un->un_uppervp; 1602 1603 if (uvp == NULLVP) 1604 return (0); 1605 1606 FIXUP(un); 1607 ap->a_vp = uvp; 1608 return (VCALL(uvp, VOFFSET(vop_readdir), ap)); 1609 } 1610 1611 int 1612 union_readlink(v) 1613 void *v; 1614 { 1615 struct vop_readlink_args /* { 1616 struct vnode *a_vp; 1617 struct uio *a_uio; 1618 struct ucred *a_cred; 1619 } */ *ap = v; 1620 int error; 1621 struct vnode *vp = OTHERVP(ap->a_vp); 1622 int dolock = (vp == LOWERVP(ap->a_vp)); 1623 1624 if (dolock) 1625 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1626 else 1627 FIXUP(VTOUNION(ap->a_vp)); 1628 ap->a_vp = vp; 1629 error = VCALL(vp, VOFFSET(vop_readlink), ap); 1630 if (dolock) 1631 VOP_UNLOCK(vp, 0); 1632 1633 return (error); 1634 } 1635 1636 int 1637 union_abortop(v) 1638 void *v; 1639 { 1640 struct vop_abortop_args /* { 1641 struct vnode *a_dvp; 1642 struct componentname *a_cnp; 1643 } */ *ap = v; 1644 int error; 1645 struct vnode *vp = OTHERVP(ap->a_dvp); 1646 struct union_node *un = VTOUNION(ap->a_dvp); 1647 int islocked = un->un_flags & UN_LOCKED; 1648 int dolock = (vp == LOWERVP(ap->a_dvp)); 1649 1650 if (islocked) { 1651 if (dolock) 1652 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1653 else 1654 FIXUP(VTOUNION(ap->a_dvp)); 1655 } 1656 ap->a_dvp = vp; 1657 error = VCALL(vp, VOFFSET(vop_abortop), ap); 1658 if (islocked && dolock) 1659 VOP_UNLOCK(vp, 0); 1660 1661 return (error); 1662 } 1663 1664 int 1665 union_inactive(v) 1666 void *v; 1667 { 1668 struct vop_inactive_args /* { 1669 struct vnode *a_vp; 1670 struct proc *a_p; 1671 } */ *ap = v; 1672 struct vnode *vp = ap->a_vp; 1673 struct union_node *un = VTOUNION(vp); 1674 struct vnode **vpp; 1675 1676 /* 1677 * Do nothing (and _don't_ bypass). 1678 * Wait to vrele lowervp until reclaim, 1679 * so that until then our union_node is in the 1680 * cache and reusable. 1681 * 1682 * NEEDSWORK: Someday, consider inactive'ing 1683 * the lowervp and then trying to reactivate it 1684 * with capabilities (v_id) 1685 * like they do in the name lookup cache code. 1686 * That's too much work for now. 1687 */ 1688 1689 if (un->un_dircache != 0) { 1690 for (vpp = un->un_dircache; *vpp != NULLVP; vpp++) 1691 vrele(*vpp); 1692 free(un->un_dircache, M_TEMP); 1693 un->un_dircache = 0; 1694 } 1695 1696 VOP_UNLOCK(vp, 0); 1697 1698 if ((un->un_flags & UN_CACHED) == 0) 1699 vgone(vp); 1700 1701 return (0); 1702 } 1703 1704 int 1705 union_reclaim(v) 1706 void *v; 1707 { 1708 struct vop_reclaim_args /* { 1709 struct vnode *a_vp; 1710 } */ *ap = v; 1711 1712 union_freevp(ap->a_vp); 1713 1714 return (0); 1715 } 1716 1717 int 1718 union_lock(v) 1719 void *v; 1720 { 1721 struct vop_lock_args /* { 1722 struct vnode *a_vp; 1723 int a_flags; 1724 } */ *ap = v; 1725 struct vnode *vp = ap->a_vp; 1726 int flags = ap->a_flags; 1727 struct union_node *un; 1728 int error; 1729 #ifdef DIAGNOSTIC 1730 int drain = 0; 1731 #endif 1732 1733 genfs_nolock(ap); 1734 /* 1735 * Need to do real lockmgr-style locking here. 1736 * in the mean time, draining won't work quite right, 1737 * which could lead to a few race conditions. 1738 * the following test was here, but is not quite right, we 1739 * still need to take the lock: 1740 if ((flags & LK_TYPE_MASK) == LK_DRAIN) 1741 return (0); 1742 */ 1743 flags &= ~LK_INTERLOCK; 1744 1745 un = VTOUNION(vp); 1746 #ifdef DIAGNOSTIC 1747 if (un->un_flags & (UN_DRAINING|UN_DRAINED)) { 1748 if (un->un_flags & UN_DRAINED) 1749 panic("union: %p: warning: locking decommissioned lock", vp); 1750 if ((flags & LK_TYPE_MASK) != LK_RELEASE) 1751 panic("union: %p: non-release on draining lock: %d", 1752 vp, flags & LK_TYPE_MASK); 1753 un->un_flags &= ~UN_DRAINING; 1754 if ((flags & LK_REENABLE) == 0) 1755 un->un_flags |= UN_DRAINED; 1756 } 1757 #endif 1758 1759 /* 1760 * Don't pass DRAIN through to sub-vnode lock; keep track of 1761 * DRAIN state at this level, and just get an exclusive lock 1762 * on the underlying vnode. 1763 */ 1764 if ((flags & LK_TYPE_MASK) == LK_DRAIN) { 1765 #ifdef DIAGNOSTIC 1766 drain = 1; 1767 #endif 1768 flags = LK_EXCLUSIVE | (flags & ~LK_TYPE_MASK); 1769 } 1770 start: 1771 un = VTOUNION(vp); 1772 1773 if (un->un_uppervp != NULLVP) { 1774 if (((un->un_flags & UN_ULOCK) == 0) && 1775 (vp->v_usecount != 0)) { 1776 /* 1777 * We MUST always use the order of: take upper 1778 * vp lock, manipulate union node flags, drop 1779 * upper vp lock. This code must not be an 1780 */ 1781 error = vn_lock(un->un_uppervp, flags); 1782 if (error) 1783 return (error); 1784 un->un_flags |= UN_ULOCK; 1785 } 1786 #ifdef DIAGNOSTIC 1787 if (un->un_flags & UN_KLOCK) { 1788 vprint("union: dangling klock", vp); 1789 panic("union: dangling upper lock (%p)", vp); 1790 } 1791 #endif 1792 } 1793 1794 /* XXX ignores LK_NOWAIT */ 1795 if (un->un_flags & UN_LOCKED) { 1796 #ifdef DIAGNOSTIC 1797 if (curproc && un->un_pid == curproc->p_pid && 1798 un->un_pid > -1 && curproc->p_pid > -1) 1799 panic("union: locking against myself"); 1800 #endif 1801 un->un_flags |= UN_WANTED; 1802 tsleep((caddr_t)&un->un_flags, PINOD, "unionlk2", 0); 1803 goto start; 1804 } 1805 1806 #ifdef DIAGNOSTIC 1807 if (curproc) 1808 un->un_pid = curproc->p_pid; 1809 else 1810 un->un_pid = -1; 1811 if (drain) 1812 un->un_flags |= UN_DRAINING; 1813 #endif 1814 1815 un->un_flags |= UN_LOCKED; 1816 return (0); 1817 } 1818 1819 /* 1820 * When operations want to vput() a union node yet retain a lock on 1821 * the upper vnode (say, to do some further operations like link(), 1822 * mkdir(), ...), they set UN_KLOCK on the union node, then call 1823 * vput() which calls VOP_UNLOCK() and comes here. union_unlock() 1824 * unlocks the union node (leaving the upper vnode alone), clears the 1825 * KLOCK flag, and then returns to vput(). The caller then does whatever 1826 * is left to do with the upper vnode, and ensures that it gets unlocked. 1827 * 1828 * If UN_KLOCK isn't set, then the upper vnode is unlocked here. 1829 */ 1830 int 1831 union_unlock(v) 1832 void *v; 1833 { 1834 struct vop_unlock_args /* { 1835 struct vnode *a_vp; 1836 int a_flags; 1837 } */ *ap = v; 1838 struct union_node *un = VTOUNION(ap->a_vp); 1839 1840 #ifdef DIAGNOSTIC 1841 if ((un->un_flags & UN_LOCKED) == 0) 1842 panic("union: unlock unlocked node"); 1843 if (curproc && un->un_pid != curproc->p_pid && 1844 curproc->p_pid > -1 && un->un_pid > -1) 1845 panic("union: unlocking other process's union node"); 1846 if (un->un_flags & UN_DRAINED) 1847 panic("union: %p: warning: unlocking decommissioned lock", ap->a_vp); 1848 #endif 1849 1850 un->un_flags &= ~UN_LOCKED; 1851 1852 if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK) 1853 VOP_UNLOCK(un->un_uppervp, 0); 1854 1855 un->un_flags &= ~(UN_ULOCK|UN_KLOCK); 1856 1857 if (un->un_flags & UN_WANTED) { 1858 un->un_flags &= ~UN_WANTED; 1859 wakeup((caddr_t) &un->un_flags); 1860 } 1861 1862 #ifdef DIAGNOSTIC 1863 un->un_pid = 0; 1864 if (un->un_flags & UN_DRAINING) { 1865 un->un_flags |= UN_DRAINED; 1866 un->un_flags &= ~UN_DRAINING; 1867 } 1868 #endif 1869 genfs_nounlock(ap); 1870 1871 return (0); 1872 } 1873 1874 int 1875 union_bmap(v) 1876 void *v; 1877 { 1878 struct vop_bmap_args /* { 1879 struct vnode *a_vp; 1880 daddr_t a_bn; 1881 struct vnode **a_vpp; 1882 daddr_t *a_bnp; 1883 int *a_runp; 1884 } */ *ap = v; 1885 int error; 1886 struct vnode *vp = OTHERVP(ap->a_vp); 1887 int dolock = (vp == LOWERVP(ap->a_vp)); 1888 1889 if (dolock) 1890 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1891 else 1892 FIXUP(VTOUNION(ap->a_vp)); 1893 ap->a_vp = vp; 1894 error = VCALL(vp, VOFFSET(vop_bmap), ap); 1895 if (dolock) 1896 VOP_UNLOCK(vp, 0); 1897 1898 return (error); 1899 } 1900 1901 int 1902 union_print(v) 1903 void *v; 1904 { 1905 struct vop_print_args /* { 1906 struct vnode *a_vp; 1907 } */ *ap = v; 1908 struct vnode *vp = ap->a_vp; 1909 1910 printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n", 1911 vp, UPPERVP(vp), LOWERVP(vp)); 1912 if (UPPERVP(vp) != NULLVP) 1913 vprint("union: upper", UPPERVP(vp)); 1914 if (LOWERVP(vp) != NULLVP) 1915 vprint("union: lower", LOWERVP(vp)); 1916 if (VTOUNION(vp)->un_dircache) { 1917 struct vnode **vpp; 1918 for (vpp = VTOUNION(vp)->un_dircache; *vpp != NULLVP; vpp++) 1919 vprint("dircache:", *vpp); 1920 } 1921 1922 return (0); 1923 } 1924 1925 int 1926 union_islocked(v) 1927 void *v; 1928 { 1929 struct vop_islocked_args /* { 1930 struct vnode *a_vp; 1931 } */ *ap = v; 1932 1933 return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0); 1934 } 1935 1936 int 1937 union_pathconf(v) 1938 void *v; 1939 { 1940 struct vop_pathconf_args /* { 1941 struct vnode *a_vp; 1942 int a_name; 1943 int *a_retval; 1944 } */ *ap = v; 1945 int error; 1946 struct vnode *vp = OTHERVP(ap->a_vp); 1947 int dolock = (vp == LOWERVP(ap->a_vp)); 1948 1949 if (dolock) 1950 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1951 else 1952 FIXUP(VTOUNION(ap->a_vp)); 1953 ap->a_vp = vp; 1954 error = VCALL(vp, VOFFSET(vop_pathconf), ap); 1955 if (dolock) 1956 VOP_UNLOCK(vp, 0); 1957 1958 return (error); 1959 } 1960 1961 int 1962 union_advlock(v) 1963 void *v; 1964 { 1965 struct vop_advlock_args /* { 1966 struct vnode *a_vp; 1967 caddr_t a_id; 1968 int a_op; 1969 struct flock *a_fl; 1970 int a_flags; 1971 } */ *ap = v; 1972 struct vnode *ovp = OTHERVP(ap->a_vp); 1973 1974 ap->a_vp = ovp; 1975 return (VCALL(ovp, VOFFSET(vop_advlock), ap)); 1976 } 1977 1978 1979 /* 1980 * XXX - vop_strategy must be hand coded because it has no 1981 * vnode in its arguments. 1982 * This goes away with a merged VM/buffer cache. 1983 */ 1984 int 1985 union_strategy(v) 1986 void *v; 1987 { 1988 struct vop_strategy_args /* { 1989 struct vnode *a_vp; 1990 struct buf *a_bp; 1991 } */ *ap = v; 1992 struct vnode *ovp = OTHERVP(ap->a_vp); 1993 struct buf *bp = ap->a_bp; 1994 1995 #ifdef DIAGNOSTIC 1996 if (ovp == NULLVP) 1997 panic("union_strategy: nil vp"); 1998 if (((bp->b_flags & B_READ) == 0) && 1999 (ovp == LOWERVP(bp->b_vp))) 2000 panic("union_strategy: writing to lowervp"); 2001 #endif 2002 2003 return (VOP_STRATEGY(ovp, bp)); 2004 } 2005 2006 int 2007 union_getpages(v) 2008 void *v; 2009 { 2010 struct vop_getpages_args /* { 2011 struct vnode *a_vp; 2012 voff_t a_offset; 2013 struct vm_page **a_m; 2014 int *a_count; 2015 int a_centeridx; 2016 vm_prot_t a_access_type; 2017 int a_advice; 2018 int a_flags; 2019 } */ *ap = v; 2020 struct vnode *vp = ap->a_vp; 2021 int error; 2022 2023 /* 2024 * just pass the request on to the underlying layer. 2025 */ 2026 2027 if (ap->a_flags & PGO_LOCKED) { 2028 return EBUSY; 2029 } 2030 ap->a_vp = OTHERVP(vp); 2031 simple_unlock(&vp->v_interlock); 2032 simple_lock(&ap->a_vp->v_interlock); 2033 error = VCALL(ap->a_vp, VOFFSET(vop_getpages), ap); 2034 return error; 2035 } 2036 2037 int 2038 union_putpages(v) 2039 void *v; 2040 { 2041 struct vop_putpages_args /* { 2042 struct vnode *a_vp; 2043 voff_t a_offlo; 2044 voff_t a_offhi; 2045 int a_flags; 2046 } */ *ap = v; 2047 struct vnode *vp = ap->a_vp; 2048 int error; 2049 2050 /* 2051 * just pass the request on to the underlying layer. 2052 */ 2053 2054 ap->a_vp = OTHERVP(vp); 2055 simple_unlock(&vp->v_interlock); 2056 simple_lock(&ap->a_vp->v_interlock); 2057 error = VCALL(ap->a_vp, VOFFSET(vop_putpages), ap); 2058 return error; 2059 } 2060 2061 int 2062 union_kqfilter(void *v) 2063 { 2064 struct vop_kqfilter_args /* { 2065 struct vnode *a_vp; 2066 struct knote *a_kn; 2067 } */ *ap = v; 2068 int error; 2069 2070 /* 2071 * We watch either the upper layer file (if it already exists), 2072 * or the lower layer one. If there is lower layer file only 2073 * at this moment, we will keep watching that lower layer file 2074 * even if upper layer file would be created later on. 2075 */ 2076 if (UPPERVP(ap->a_vp)) 2077 error = VOP_KQFILTER(UPPERVP(ap->a_vp), ap->a_kn); 2078 else if (LOWERVP(ap->a_vp)) 2079 error = VOP_KQFILTER(LOWERVP(ap->a_vp), ap->a_kn); 2080 else { 2081 /* panic? */ 2082 error = EOPNOTSUPP; 2083 } 2084 2085 return (error); 2086 }
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