union_vnops.c revision 1.51
1/* $NetBSD: union_vnops.c,v 1.51 2014/01/23 10:13:56 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 1.51 2014/01/23 10:13:56 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 <sys/kauth.h> 91 92#include <fs/union/union.h> 93#include <miscfs/genfs/genfs.h> 94#include <miscfs/specfs/specdev.h> 95 96int union_lookup(void *); 97int union_create(void *); 98int union_whiteout(void *); 99int union_mknod(void *); 100int union_open(void *); 101int union_close(void *); 102int union_access(void *); 103int union_getattr(void *); 104int union_setattr(void *); 105int union_read(void *); 106int union_write(void *); 107int union_ioctl(void *); 108int union_poll(void *); 109int union_revoke(void *); 110int union_mmap(void *); 111int union_fsync(void *); 112int union_seek(void *); 113int union_remove(void *); 114int union_link(void *); 115int union_rename(void *); 116int union_mkdir(void *); 117int union_rmdir(void *); 118int union_symlink(void *); 119int union_readdir(void *); 120int union_readlink(void *); 121int union_abortop(void *); 122int union_inactive(void *); 123int union_reclaim(void *); 124int union_lock(void *); 125int union_unlock(void *); 126int union_bmap(void *); 127int union_print(void *); 128int union_islocked(void *); 129int union_pathconf(void *); 130int union_advlock(void *); 131int union_strategy(void *); 132int union_bwrite(void *); 133int union_getpages(void *); 134int union_putpages(void *); 135int union_kqfilter(void *); 136 137static int union_lookup1(struct vnode *, struct vnode **, 138 struct vnode **, struct componentname *); 139 140 141/* 142 * Global vfs data structures 143 */ 144int (**union_vnodeop_p)(void *); 145const struct vnodeopv_entry_desc union_vnodeop_entries[] = { 146 { &vop_default_desc, vn_default_error }, 147 { &vop_lookup_desc, union_lookup }, /* lookup */ 148 { &vop_create_desc, union_create }, /* create */ 149 { &vop_whiteout_desc, union_whiteout }, /* whiteout */ 150 { &vop_mknod_desc, union_mknod }, /* mknod */ 151 { &vop_open_desc, union_open }, /* open */ 152 { &vop_close_desc, union_close }, /* close */ 153 { &vop_access_desc, union_access }, /* access */ 154 { &vop_getattr_desc, union_getattr }, /* getattr */ 155 { &vop_setattr_desc, union_setattr }, /* setattr */ 156 { &vop_read_desc, union_read }, /* read */ 157 { &vop_write_desc, union_write }, /* write */ 158 { &vop_ioctl_desc, union_ioctl }, /* ioctl */ 159 { &vop_poll_desc, union_poll }, /* select */ 160 { &vop_revoke_desc, union_revoke }, /* revoke */ 161 { &vop_mmap_desc, union_mmap }, /* mmap */ 162 { &vop_fsync_desc, union_fsync }, /* fsync */ 163 { &vop_seek_desc, union_seek }, /* seek */ 164 { &vop_remove_desc, union_remove }, /* remove */ 165 { &vop_link_desc, union_link }, /* link */ 166 { &vop_rename_desc, union_rename }, /* rename */ 167 { &vop_mkdir_desc, union_mkdir }, /* mkdir */ 168 { &vop_rmdir_desc, union_rmdir }, /* rmdir */ 169 { &vop_symlink_desc, union_symlink }, /* symlink */ 170 { &vop_readdir_desc, union_readdir }, /* readdir */ 171 { &vop_readlink_desc, union_readlink }, /* readlink */ 172 { &vop_abortop_desc, union_abortop }, /* abortop */ 173 { &vop_inactive_desc, union_inactive }, /* inactive */ 174 { &vop_reclaim_desc, union_reclaim }, /* reclaim */ 175 { &vop_lock_desc, union_lock }, /* lock */ 176 { &vop_unlock_desc, union_unlock }, /* unlock */ 177 { &vop_bmap_desc, union_bmap }, /* bmap */ 178 { &vop_strategy_desc, union_strategy }, /* strategy */ 179 { &vop_bwrite_desc, union_bwrite }, /* bwrite */ 180 { &vop_print_desc, union_print }, /* print */ 181 { &vop_islocked_desc, union_islocked }, /* islocked */ 182 { &vop_pathconf_desc, union_pathconf }, /* pathconf */ 183 { &vop_advlock_desc, union_advlock }, /* advlock */ 184 { &vop_getpages_desc, union_getpages }, /* getpages */ 185 { &vop_putpages_desc, union_putpages }, /* putpages */ 186 { &vop_kqfilter_desc, union_kqfilter }, /* kqfilter */ 187 { NULL, NULL } 188}; 189const struct vnodeopv_desc union_vnodeop_opv_desc = 190 { &union_vnodeop_p, union_vnodeop_entries }; 191 192#define NODE_IS_SPECIAL(vp) \ 193 ((vp)->v_type == VBLK || (vp)->v_type == VCHR || \ 194 (vp)->v_type == VSOCK || (vp)->v_type == VFIFO) 195 196static int 197union_lookup1(struct vnode *udvp, struct vnode **dvpp, struct vnode **vpp, 198 struct componentname *cnp) 199{ 200 int error; 201 struct vnode *tdvp; 202 struct vnode *dvp; 203 struct mount *mp; 204 205 dvp = *dvpp; 206 207 /* 208 * If stepping up the directory tree, check for going 209 * back across the mount point, in which case do what 210 * lookup would do by stepping back down the mount 211 * hierarchy. 212 */ 213 if (cnp->cn_flags & ISDOTDOT) { 214 while ((dvp != udvp) && (dvp->v_vflag & VV_ROOT)) { 215 /* 216 * Don't do the NOCROSSMOUNT check 217 * at this level. By definition, 218 * union fs deals with namespaces, not 219 * filesystems. 220 */ 221 tdvp = dvp; 222 *dvpp = dvp = dvp->v_mount->mnt_vnodecovered; 223 VOP_UNLOCK(tdvp); 224 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 225 } 226 } 227 228 error = VOP_LOOKUP(dvp, &tdvp, cnp); 229 if (error) 230 return (error); 231 232 dvp = tdvp; 233 234 /* 235 * Lastly check if the current node is a mount point in 236 * which case walk up the mount hierarchy making sure not to 237 * bump into the root of the mount tree (ie. dvp != udvp). 238 */ 239 while (dvp != udvp && (dvp->v_type == VDIR) && 240 (mp = dvp->v_mountedhere)) { 241 if (vfs_busy(mp, NULL)) 242 continue; 243 vput(dvp); 244 error = VFS_ROOT(mp, &tdvp); 245 vfs_unbusy(mp, false, NULL); 246 if (error) { 247 return (error); 248 } 249 dvp = tdvp; 250 } 251 252 *vpp = dvp; 253 return (0); 254} 255 256int 257union_lookup(void *v) 258{ 259 struct vop_lookup_args /* { 260 struct vnodeop_desc *a_desc; 261 struct vnode *a_dvp; 262 struct vnode **a_vpp; 263 struct componentname *a_cnp; 264 } */ *ap = v; 265 int error; 266 int uerror, lerror; 267 struct vnode *uppervp, *lowervp; 268 struct vnode *upperdvp, *lowerdvp; 269 struct vnode *dvp = ap->a_dvp; 270 struct union_node *dun = VTOUNION(dvp); 271 struct componentname *cnp = ap->a_cnp; 272 struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); 273 kauth_cred_t saved_cred = NULL; 274 int iswhiteout; 275 struct vattr va; 276 277#ifdef notyet 278 if (cnp->cn_namelen == 3 && 279 cnp->cn_nameptr[2] == '.' && 280 cnp->cn_nameptr[1] == '.' && 281 cnp->cn_nameptr[0] == '.') { 282 dvp = *ap->a_vpp = LOWERVP(ap->a_dvp); 283 if (dvp == NULLVP) 284 return (ENOENT); 285 vref(dvp); 286 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 287 return (0); 288 } 289#endif 290 291 if ((cnp->cn_flags & ISLASTCN) && 292 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 293 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 294 return (EROFS); 295 296start: 297 upperdvp = dun->un_uppervp; 298 lowerdvp = dun->un_lowervp; 299 uppervp = NULLVP; 300 lowervp = NULLVP; 301 iswhiteout = 0; 302 303 /* 304 * do the lookup in the upper level. 305 * if that level comsumes additional pathnames, 306 * then assume that something special is going 307 * on and just return that vnode. 308 */ 309 if (upperdvp != NULLVP) { 310 uerror = union_lookup1(um->um_uppervp, &upperdvp, 311 &uppervp, cnp); 312 if (cnp->cn_consume != 0) { 313 *ap->a_vpp = uppervp; 314 return (uerror); 315 } 316 if (uerror == ENOENT || uerror == EJUSTRETURN) { 317 if (cnp->cn_flags & ISWHITEOUT) { 318 iswhiteout = 1; 319 } else if (lowerdvp != NULLVP) { 320 lerror = VOP_GETATTR(upperdvp, &va, 321 cnp->cn_cred); 322 if (lerror == 0 && (va.va_flags & OPAQUE)) 323 iswhiteout = 1; 324 } 325 } 326 } else { 327 uerror = ENOENT; 328 } 329 330 /* 331 * in a similar way to the upper layer, do the lookup 332 * in the lower layer. this time, if there is some 333 * component magic going on, then vput whatever we got 334 * back from the upper layer and return the lower vnode 335 * instead. 336 */ 337 if (lowerdvp != NULLVP && !iswhiteout) { 338 int nameiop; 339 340 vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY); 341 342 /* 343 * Only do a LOOKUP on the bottom node, since 344 * we won't be making changes to it anyway. 345 */ 346 nameiop = cnp->cn_nameiop; 347 cnp->cn_nameiop = LOOKUP; 348 if (um->um_op == UNMNT_BELOW) { 349 saved_cred = cnp->cn_cred; 350 cnp->cn_cred = um->um_cred; 351 } 352 353 /* 354 * we shouldn't have to worry about locking interactions 355 * between the lower layer and our union layer (w.r.t. 356 * `..' processing) because we don't futz with lowervp 357 * locks in the union-node instantiation code path. 358 */ 359 lerror = union_lookup1(um->um_lowervp, &lowerdvp, 360 &lowervp, cnp); 361 if (um->um_op == UNMNT_BELOW) 362 cnp->cn_cred = saved_cred; 363 cnp->cn_nameiop = nameiop; 364 365 if (lowervp != lowerdvp) 366 VOP_UNLOCK(lowerdvp); 367 368 if (cnp->cn_consume != 0) { 369 if (uppervp != NULLVP) { 370 if (uppervp == upperdvp) 371 vrele(uppervp); 372 else 373 vput(uppervp); 374 uppervp = NULLVP; 375 } 376 *ap->a_vpp = lowervp; 377 return (lerror); 378 } 379 } else { 380 lerror = ENOENT; 381 if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) { 382 lowervp = LOWERVP(dun->un_pvp); 383 if (lowervp != NULLVP) { 384 vref(lowervp); 385 vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY); 386 lerror = 0; 387 } 388 } 389 } 390 391 /* 392 * EJUSTRETURN is used by underlying filesystems to indicate that 393 * a directory modification op was started successfully. 394 * This will only happen in the upper layer, since 395 * the lower layer only does LOOKUPs. 396 * If this union is mounted read-only, bounce it now. 397 */ 398 399 if ((uerror == EJUSTRETURN) && (cnp->cn_flags & ISLASTCN) && 400 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 401 ((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME))) 402 uerror = EROFS; 403 404 /* 405 * at this point, we have uerror and lerror indicating 406 * possible errors with the lookups in the upper and lower 407 * layers. additionally, uppervp and lowervp are (locked) 408 * references to existing vnodes in the upper and lower layers. 409 * 410 * there are now three cases to consider. 411 * 1. if both layers returned an error, then return whatever 412 * error the upper layer generated. 413 * 414 * 2. if the top layer failed and the bottom layer succeeded 415 * then two subcases occur. 416 * a. the bottom vnode is not a directory, in which 417 * case just return a new union vnode referencing 418 * an empty top layer and the existing bottom layer. 419 * b. the bottom vnode is a directory, in which case 420 * create a new directory in the top-level and 421 * continue as in case 3. 422 * 423 * 3. if the top layer succeeded then return a new union 424 * vnode referencing whatever the new top layer and 425 * whatever the bottom layer returned. 426 */ 427 428 *ap->a_vpp = NULLVP; 429 430 431 /* case 1. */ 432 if ((uerror != 0) && (lerror != 0)) { 433 return (uerror); 434 } 435 436 /* case 2. */ 437 if (uerror != 0 /* && (lerror == 0) */ ) { 438 if (lowervp->v_type == VDIR) { /* case 2b. */ 439 /* 440 * We may be racing another process to make the 441 * upper-level shadow directory. Be careful with 442 * locks/etc! 443 * If we have to create a shadow directory and want 444 * to commit the node we have to restart the lookup 445 * to get the componentname right. 446 */ 447 if (upperdvp) { 448 VOP_UNLOCK(upperdvp); 449 uerror = union_mkshadow(um, upperdvp, cnp, 450 &uppervp); 451 vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY); 452 if (uerror == 0 && cnp->cn_nameiop != LOOKUP) { 453 vrele(uppervp); 454 if (lowervp != NULLVP) 455 vput(lowervp); 456 goto start; 457 } 458 /* 459 * XXX: lock upper node until lookup returns 460 * unlocked nodes. 461 */ 462 vn_lock(uppervp, LK_EXCLUSIVE | LK_RETRY); 463 } 464 if (uerror) { 465 if (lowervp != NULLVP) { 466 vput(lowervp); 467 lowervp = NULLVP; 468 } 469 return (uerror); 470 } 471 } 472 } 473 474 if (lowervp != NULLVP) 475 VOP_UNLOCK(lowervp); 476 477 error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, 478 uppervp, lowervp, 1); 479 480 if (error) { 481 if (uppervp != NULLVP) 482 vput(uppervp); 483 if (lowervp != NULLVP) 484 vrele(lowervp); 485 } 486 487 return (error); 488} 489 490int 491union_create(void *v) 492{ 493 struct vop_create_v3_args /* { 494 struct vnode *a_dvp; 495 struct vnode **a_vpp; 496 struct componentname *a_cnp; 497 struct vattr *a_vap; 498 } */ *ap = v; 499 struct union_node *un = VTOUNION(ap->a_dvp); 500 struct vnode *dvp = un->un_uppervp; 501 struct componentname *cnp = ap->a_cnp; 502 503 if (dvp != NULLVP) { 504 int error; 505 struct vnode *vp; 506 struct mount *mp; 507 508 mp = ap->a_dvp->v_mount; 509 error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap); 510 if (error) 511 return (error); 512 513 /* XXX: lock upper node until lookup returns unlocked nodes. */ 514 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 515 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp, 516 NULLVP, 1); 517 VOP_UNLOCK(vp); 518 if (error) 519 vrele(vp); 520 return (error); 521 } 522 523 return (EROFS); 524} 525 526int 527union_whiteout(void *v) 528{ 529 struct vop_whiteout_args /* { 530 struct vnode *a_dvp; 531 struct componentname *a_cnp; 532 int a_flags; 533 } */ *ap = v; 534 struct union_node *un = VTOUNION(ap->a_dvp); 535 struct componentname *cnp = ap->a_cnp; 536 537 if (un->un_uppervp == NULLVP) 538 return (EOPNOTSUPP); 539 540 return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags)); 541} 542 543int 544union_mknod(void *v) 545{ 546 struct vop_mknod_v3_args /* { 547 struct vnode *a_dvp; 548 struct vnode **a_vpp; 549 struct componentname *a_cnp; 550 struct vattr *a_vap; 551 } */ *ap = v; 552 struct union_node *un = VTOUNION(ap->a_dvp); 553 struct vnode *dvp = un->un_uppervp; 554 struct componentname *cnp = ap->a_cnp; 555 556 if (dvp != NULLVP) { 557 int error; 558 struct vnode *vp; 559 struct mount *mp; 560 561 mp = ap->a_dvp->v_mount; 562 error = VOP_MKNOD(dvp, &vp, cnp, ap->a_vap); 563 if (error) 564 return (error); 565 566 /* XXX: lock upper node until lookup returns unlocked nodes. */ 567 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 568 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, 569 cnp, vp, NULLVP, 1); 570 VOP_UNLOCK(vp); 571 if (error) 572 vrele(vp); 573 return (error); 574 } 575 576 return (EROFS); 577} 578 579int 580union_open(void *v) 581{ 582 struct vop_open_args /* { 583 struct vnodeop_desc *a_desc; 584 struct vnode *a_vp; 585 int a_mode; 586 kauth_cred_t a_cred; 587 } */ *ap = v; 588 struct union_node *un = VTOUNION(ap->a_vp); 589 struct vnode *tvp; 590 int mode = ap->a_mode; 591 kauth_cred_t cred = ap->a_cred; 592 struct lwp *l = curlwp; 593 int error; 594 595 /* 596 * If there is an existing upper vp then simply open that. 597 */ 598 tvp = un->un_uppervp; 599 if (tvp == NULLVP) { 600 /* 601 * If the lower vnode is being opened for writing, then 602 * copy the file contents to the upper vnode and open that, 603 * otherwise can simply open the lower vnode. 604 */ 605 tvp = un->un_lowervp; 606 if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) { 607 error = union_copyup(un, (mode&O_TRUNC) == 0, cred, l); 608 if (error == 0) 609 error = VOP_OPEN(un->un_uppervp, mode, cred); 610 return (error); 611 } 612 613 /* 614 * Just open the lower vnode, but check for nodev mount flag 615 */ 616 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 617 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 618 return ENXIO; 619 un->un_openl++; 620 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); 621 error = VOP_OPEN(tvp, mode, cred); 622 VOP_UNLOCK(tvp); 623 624 return (error); 625 } 626 /* 627 * Just open the upper vnode, checking for nodev mount flag first 628 */ 629 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 630 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 631 return ENXIO; 632 633 error = VOP_OPEN(tvp, mode, cred); 634 635 return (error); 636} 637 638int 639union_close(void *v) 640{ 641 struct vop_close_args /* { 642 struct vnode *a_vp; 643 int a_fflag; 644 kauth_cred_t a_cred; 645 } */ *ap = v; 646 struct union_node *un = VTOUNION(ap->a_vp); 647 struct vnode *vp; 648 int error; 649 bool do_lock; 650 651 vp = un->un_uppervp; 652 if (vp != NULLVP) { 653 do_lock = false; 654 } else { 655 KASSERT(un->un_openl > 0); 656 --un->un_openl; 657 vp = un->un_lowervp; 658 do_lock = true; 659 } 660 661 KASSERT(vp != NULLVP); 662 ap->a_vp = vp; 663 if (do_lock) 664 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 665 error = VCALL(vp, VOFFSET(vop_close), ap); 666 if (do_lock) 667 VOP_UNLOCK(vp); 668 669 return error; 670} 671 672/* 673 * Check access permission on the union vnode. 674 * The access check being enforced is to check 675 * against both the underlying vnode, and any 676 * copied vnode. This ensures that no additional 677 * file permissions are given away simply because 678 * the user caused an implicit file copy. 679 */ 680int 681union_access(void *v) 682{ 683 struct vop_access_args /* { 684 struct vnodeop_desc *a_desc; 685 struct vnode *a_vp; 686 int a_mode; 687 kauth_cred_t a_cred; 688 } */ *ap = v; 689 struct vnode *vp = ap->a_vp; 690 struct union_node *un = VTOUNION(vp); 691 int error = EACCES; 692 struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount); 693 694 /* 695 * Disallow write attempts on read-only file systems; 696 * unless the file is a socket, fifo, or a block or 697 * character device resident on the file system. 698 */ 699 if (ap->a_mode & VWRITE) { 700 switch (vp->v_type) { 701 case VDIR: 702 case VLNK: 703 case VREG: 704 if (vp->v_mount->mnt_flag & MNT_RDONLY) 705 return (EROFS); 706 break; 707 case VBAD: 708 case VBLK: 709 case VCHR: 710 case VSOCK: 711 case VFIFO: 712 case VNON: 713 default: 714 break; 715 } 716 } 717 718 719 if ((vp = un->un_uppervp) != NULLVP) { 720 ap->a_vp = vp; 721 return (VCALL(vp, VOFFSET(vop_access), ap)); 722 } 723 724 if ((vp = un->un_lowervp) != NULLVP) { 725 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 726 ap->a_vp = vp; 727 error = VCALL(vp, VOFFSET(vop_access), ap); 728 if (error == 0) { 729 if (um->um_op == UNMNT_BELOW) { 730 ap->a_cred = um->um_cred; 731 error = VCALL(vp, VOFFSET(vop_access), ap); 732 } 733 } 734 VOP_UNLOCK(vp); 735 if (error) 736 return (error); 737 } 738 739 return (error); 740} 741 742/* 743 * We handle getattr only to change the fsid and 744 * track object sizes 745 */ 746int 747union_getattr(void *v) 748{ 749 struct vop_getattr_args /* { 750 struct vnode *a_vp; 751 struct vattr *a_vap; 752 kauth_cred_t a_cred; 753 } */ *ap = v; 754 int error; 755 struct union_node *un = VTOUNION(ap->a_vp); 756 struct vnode *vp = un->un_uppervp; 757 struct vattr *vap; 758 struct vattr va; 759 760 761 /* 762 * Some programs walk the filesystem hierarchy by counting 763 * links to directories to avoid stat'ing all the time. 764 * This means the link count on directories needs to be "correct". 765 * The only way to do that is to call getattr on both layers 766 * and fix up the link count. The link count will not necessarily 767 * be accurate but will be large enough to defeat the tree walkers. 768 * 769 * To make life more interesting, some filesystems don't keep 770 * track of link counts in the expected way, and return a 771 * link count of `1' for those directories; if either of the 772 * component directories returns a link count of `1', we return a 1. 773 */ 774 775 vap = ap->a_vap; 776 777 vp = un->un_uppervp; 778 if (vp != NULLVP) { 779 error = VOP_GETATTR(vp, vap, ap->a_cred); 780 if (error) 781 return (error); 782 mutex_enter(&un->un_lock); 783 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 784 } 785 786 if (vp == NULLVP) { 787 vp = un->un_lowervp; 788 } else if (vp->v_type == VDIR) { 789 vp = un->un_lowervp; 790 if (vp != NULLVP) 791 vap = &va; 792 } else { 793 vp = NULLVP; 794 } 795 796 if (vp != NULLVP) { 797 if (vp == un->un_lowervp) 798 vn_lock(vp, LK_SHARED | LK_RETRY); 799 error = VOP_GETATTR(vp, vap, ap->a_cred); 800 if (vp == un->un_lowervp) 801 VOP_UNLOCK(vp); 802 if (error) 803 return (error); 804 mutex_enter(&un->un_lock); 805 union_newsize(ap->a_vp, VNOVAL, vap->va_size); 806 } 807 808 if ((vap != ap->a_vap) && (vap->va_type == VDIR)) { 809 /* 810 * Link count manipulation: 811 * - If both return "2", return 2 (no subdirs) 812 * - If one or the other return "1", return "1" (ENOCLUE) 813 */ 814 if ((ap->a_vap->va_nlink == 2) && 815 (vap->va_nlink == 2)) 816 ; 817 else if (ap->a_vap->va_nlink != 1) { 818 if (vap->va_nlink == 1) 819 ap->a_vap->va_nlink = 1; 820 else 821 ap->a_vap->va_nlink += vap->va_nlink; 822 } 823 } 824 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0]; 825 return (0); 826} 827 828int 829union_setattr(void *v) 830{ 831 struct vop_setattr_args /* { 832 struct vnode *a_vp; 833 struct vattr *a_vap; 834 kauth_cred_t a_cred; 835 } */ *ap = v; 836 struct vattr *vap = ap->a_vap; 837 struct vnode *vp = ap->a_vp; 838 struct union_node *un = VTOUNION(vp); 839 bool size_only; /* All but va_size are VNOVAL. */ 840 int error; 841 842 size_only = (vap->va_flags == VNOVAL && vap->va_uid == (uid_t)VNOVAL && 843 vap->va_gid == (gid_t)VNOVAL && vap->va_atime.tv_sec == VNOVAL && 844 vap->va_mtime.tv_sec == VNOVAL && vap->va_mode == (mode_t)VNOVAL); 845 846 if (!size_only && (vp->v_mount->mnt_flag & MNT_RDONLY)) 847 return (EROFS); 848 if (vap->va_size != VNOVAL) { 849 switch (vp->v_type) { 850 case VDIR: 851 return (EISDIR); 852 case VCHR: 853 case VBLK: 854 case VSOCK: 855 case VFIFO: 856 break; 857 case VREG: 858 case VLNK: 859 default: 860 /* 861 * Disallow write attempts if the filesystem is 862 * mounted read-only. 863 */ 864 if (vp->v_mount->mnt_flag & MNT_RDONLY) 865 return (EROFS); 866 } 867 } 868 869 /* 870 * Handle case of truncating lower object to zero size, 871 * by creating a zero length upper object. This is to 872 * handle the case of open with O_TRUNC and O_CREAT. 873 */ 874 if ((un->un_uppervp == NULLVP) && 875 /* assert(un->un_lowervp != NULLVP) */ 876 (un->un_lowervp->v_type == VREG)) { 877 error = union_copyup(un, (vap->va_size != 0), 878 ap->a_cred, curlwp); 879 if (error) 880 return (error); 881 } 882 883 /* 884 * Try to set attributes in upper layer, ignore size change to zero 885 * for devices to handle O_TRUNC and return read-only filesystem error 886 * otherwise. 887 */ 888 if (un->un_uppervp != NULLVP) { 889 error = VOP_SETATTR(un->un_uppervp, vap, ap->a_cred); 890 if ((error == 0) && (vap->va_size != VNOVAL)) { 891 mutex_enter(&un->un_lock); 892 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 893 } 894 } else { 895 KASSERT(un->un_lowervp != NULLVP); 896 if (NODE_IS_SPECIAL(un->un_lowervp)) { 897 if (size_only && 898 (vap->va_size == 0 || vap->va_size == VNOVAL)) 899 error = 0; 900 else 901 error = EROFS; 902 } else { 903 error = EROFS; 904 } 905 } 906 907 return (error); 908} 909 910int 911union_read(void *v) 912{ 913 struct vop_read_args /* { 914 struct vnode *a_vp; 915 struct uio *a_uio; 916 int a_ioflag; 917 kauth_cred_t a_cred; 918 } */ *ap = v; 919 int error; 920 struct vnode *vp = OTHERVP(ap->a_vp); 921 int dolock = (vp == LOWERVP(ap->a_vp)); 922 923 if (dolock) 924 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 925 error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 926 if (dolock) 927 VOP_UNLOCK(vp); 928 929 /* 930 * XXX 931 * perhaps the size of the underlying object has changed under 932 * our feet. take advantage of the offset information present 933 * in the uio structure. 934 */ 935 if (error == 0) { 936 struct union_node *un = VTOUNION(ap->a_vp); 937 off_t cur = ap->a_uio->uio_offset; 938 off_t usz = VNOVAL, lsz = VNOVAL; 939 940 mutex_enter(&un->un_lock); 941 if (vp == un->un_uppervp) { 942 if (cur > un->un_uppersz) 943 usz = cur; 944 } else { 945 if (cur > un->un_lowersz) 946 lsz = cur; 947 } 948 949 if (usz != VNOVAL || lsz != VNOVAL) 950 union_newsize(ap->a_vp, usz, lsz); 951 else 952 mutex_exit(&un->un_lock); 953 } 954 955 return (error); 956} 957 958int 959union_write(void *v) 960{ 961 struct vop_read_args /* { 962 struct vnode *a_vp; 963 struct uio *a_uio; 964 int a_ioflag; 965 kauth_cred_t a_cred; 966 } */ *ap = v; 967 int error; 968 struct vnode *vp; 969 struct union_node *un = VTOUNION(ap->a_vp); 970 971 vp = UPPERVP(ap->a_vp); 972 if (vp == NULLVP) { 973 vp = LOWERVP(ap->a_vp); 974 if (NODE_IS_SPECIAL(vp)) { 975 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 976 error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, 977 ap->a_cred); 978 VOP_UNLOCK(vp); 979 return error; 980 } 981 panic("union: missing upper layer in write"); 982 } 983 984 error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 985 986 /* 987 * the size of the underlying object may be changed by the 988 * write. 989 */ 990 if (error == 0) { 991 off_t cur = ap->a_uio->uio_offset; 992 993 mutex_enter(&un->un_lock); 994 if (cur > un->un_uppersz) 995 union_newsize(ap->a_vp, cur, VNOVAL); 996 else 997 mutex_exit(&un->un_lock); 998 } 999 1000 return (error); 1001} 1002 1003int 1004union_ioctl(void *v) 1005{ 1006 struct vop_ioctl_args /* { 1007 struct vnode *a_vp; 1008 int a_command; 1009 void *a_data; 1010 int a_fflag; 1011 kauth_cred_t a_cred; 1012 } */ *ap = v; 1013 struct vnode *ovp = OTHERVP(ap->a_vp); 1014 1015 ap->a_vp = ovp; 1016 return (VCALL(ovp, VOFFSET(vop_ioctl), ap)); 1017} 1018 1019int 1020union_poll(void *v) 1021{ 1022 struct vop_poll_args /* { 1023 struct vnode *a_vp; 1024 int a_events; 1025 } */ *ap = v; 1026 struct vnode *ovp = OTHERVP(ap->a_vp); 1027 1028 ap->a_vp = ovp; 1029 return (VCALL(ovp, VOFFSET(vop_poll), ap)); 1030} 1031 1032int 1033union_revoke(void *v) 1034{ 1035 struct vop_revoke_args /* { 1036 struct vnode *a_vp; 1037 int a_flags; 1038 struct proc *a_p; 1039 } */ *ap = v; 1040 struct vnode *vp = ap->a_vp; 1041 1042 if (UPPERVP(vp)) 1043 VOP_REVOKE(UPPERVP(vp), ap->a_flags); 1044 if (LOWERVP(vp)) 1045 VOP_REVOKE(LOWERVP(vp), ap->a_flags); 1046 vgone(vp); /* XXXAD?? */ 1047 return (0); 1048} 1049 1050int 1051union_mmap(void *v) 1052{ 1053 struct vop_mmap_args /* { 1054 struct vnode *a_vp; 1055 vm_prot_t a_prot; 1056 kauth_cred_t a_cred; 1057 } */ *ap = v; 1058 struct vnode *ovp = OTHERVP(ap->a_vp); 1059 1060 ap->a_vp = ovp; 1061 return (VCALL(ovp, VOFFSET(vop_mmap), ap)); 1062} 1063 1064int 1065union_fsync(void *v) 1066{ 1067 struct vop_fsync_args /* { 1068 struct vnode *a_vp; 1069 kauth_cred_t a_cred; 1070 int a_flags; 1071 off_t offhi; 1072 off_t offlo; 1073 } */ *ap = v; 1074 int error = 0; 1075 struct vnode *targetvp; 1076 1077 /* 1078 * If vinvalbuf is calling us, it's a "shallow fsync" -- don't 1079 * bother syncing the underlying vnodes, since (a) they'll be 1080 * fsync'ed when reclaimed and (b) we could deadlock if 1081 * they're locked; otherwise, pass it through to the 1082 * underlying layer. 1083 */ 1084 if (ap->a_vp->v_type == VBLK || ap->a_vp->v_type == VCHR) { 1085 error = spec_fsync(v); 1086 if (error) 1087 return error; 1088 } 1089 1090 if (ap->a_flags & FSYNC_RECLAIM) 1091 return 0; 1092 1093 targetvp = OTHERVP(ap->a_vp); 1094 if (targetvp != NULLVP) { 1095 int dolock = (targetvp == LOWERVP(ap->a_vp)); 1096 1097 if (dolock) 1098 vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY); 1099 error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags, 1100 ap->a_offlo, ap->a_offhi); 1101 if (dolock) 1102 VOP_UNLOCK(targetvp); 1103 } 1104 1105 return (error); 1106} 1107 1108int 1109union_seek(void *v) 1110{ 1111 struct vop_seek_args /* { 1112 struct vnode *a_vp; 1113 off_t a_oldoff; 1114 off_t a_newoff; 1115 kauth_cred_t a_cred; 1116 } */ *ap = v; 1117 struct vnode *ovp = OTHERVP(ap->a_vp); 1118 1119 ap->a_vp = ovp; 1120 return (VCALL(ovp, VOFFSET(vop_seek), ap)); 1121} 1122 1123int 1124union_remove(void *v) 1125{ 1126 struct vop_remove_args /* { 1127 struct vnode *a_dvp; 1128 struct vnode *a_vp; 1129 struct componentname *a_cnp; 1130 } */ *ap = v; 1131 int error; 1132 struct union_node *dun = VTOUNION(ap->a_dvp); 1133 struct union_node *un = VTOUNION(ap->a_vp); 1134 struct componentname *cnp = ap->a_cnp; 1135 1136 if (dun->un_uppervp == NULLVP) 1137 panic("union remove: null upper vnode"); 1138 1139 if (un->un_uppervp != NULLVP) { 1140 struct vnode *dvp = dun->un_uppervp; 1141 struct vnode *vp = un->un_uppervp; 1142 1143 vref(dvp); 1144 dun->un_flags |= UN_KLOCK; 1145 vput(ap->a_dvp); 1146 vref(vp); 1147 un->un_flags |= UN_KLOCK; 1148 vput(ap->a_vp); 1149 1150 if (union_dowhiteout(un, cnp->cn_cred)) 1151 cnp->cn_flags |= DOWHITEOUT; 1152 error = VOP_REMOVE(dvp, vp, cnp); 1153 if (!error) 1154 union_removed_upper(un); 1155 } else { 1156 error = union_mkwhiteout( 1157 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1158 dun->un_uppervp, ap->a_cnp, un); 1159 vput(ap->a_dvp); 1160 vput(ap->a_vp); 1161 } 1162 1163 return (error); 1164} 1165 1166int 1167union_link(void *v) 1168{ 1169 struct vop_link_args /* { 1170 struct vnode *a_dvp; 1171 struct vnode *a_vp; 1172 struct componentname *a_cnp; 1173 } */ *ap = v; 1174 int error = 0; 1175 struct componentname *cnp = ap->a_cnp; 1176 struct union_node *dun; 1177 struct vnode *vp; 1178 struct vnode *dvp; 1179 1180 dun = VTOUNION(ap->a_dvp); 1181 1182 KASSERT((ap->a_cnp->cn_flags & LOCKPARENT) != 0); 1183 1184 if (ap->a_dvp->v_op != ap->a_vp->v_op) { 1185 vp = ap->a_vp; 1186 } else { 1187 struct union_node *un = VTOUNION(ap->a_vp); 1188 if (un->un_uppervp == NULLVP) { 1189 const bool droplock = (dun->un_uppervp == un->un_dirvp); 1190 1191 /* 1192 * Needs to be copied before we can link it. 1193 */ 1194 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY); 1195 if (droplock) 1196 VOP_UNLOCK(dun->un_uppervp); 1197 error = union_copyup(un, 1, cnp->cn_cred, curlwp); 1198 if (droplock) { 1199 vn_lock(dun->un_uppervp, 1200 LK_EXCLUSIVE | LK_RETRY); 1201 /* 1202 * During copyup, we dropped the lock on the 1203 * dir and invalidated any saved namei lookup 1204 * state for the directory we'll be entering 1205 * the link in. We need to re-run the lookup 1206 * in that directory to reset any state needed 1207 * for VOP_LINK. 1208 * Call relookup on the union-layer to reset 1209 * the state. 1210 */ 1211 vp = NULLVP; 1212 if (dun->un_uppervp == NULLVP) 1213 panic("union: null upperdvp?"); 1214 error = relookup(ap->a_dvp, &vp, ap->a_cnp, 0); 1215 if (error) { 1216 VOP_UNLOCK(ap->a_vp); 1217 return EROFS; /* ? */ 1218 } 1219 if (vp != NULLVP) { 1220 /* 1221 * The name we want to create has 1222 * mysteriously appeared (a race?) 1223 */ 1224 error = EEXIST; 1225 VOP_UNLOCK(ap->a_vp); 1226 vput(ap->a_dvp); 1227 vput(vp); 1228 return (error); 1229 } 1230 } 1231 VOP_UNLOCK(ap->a_vp); 1232 } 1233 vp = un->un_uppervp; 1234 } 1235 1236 dvp = dun->un_uppervp; 1237 if (dvp == NULLVP) 1238 error = EROFS; 1239 1240 if (error) { 1241 vput(ap->a_dvp); 1242 return (error); 1243 } 1244 1245 vref(dvp); 1246 dun->un_flags |= UN_KLOCK; 1247 vput(ap->a_dvp); 1248 1249 return (VOP_LINK(dvp, vp, cnp)); 1250} 1251 1252int 1253union_rename(void *v) 1254{ 1255 struct vop_rename_args /* { 1256 struct vnode *a_fdvp; 1257 struct vnode *a_fvp; 1258 struct componentname *a_fcnp; 1259 struct vnode *a_tdvp; 1260 struct vnode *a_tvp; 1261 struct componentname *a_tcnp; 1262 } */ *ap = v; 1263 int error; 1264 1265 struct vnode *fdvp = ap->a_fdvp; 1266 struct vnode *fvp = ap->a_fvp; 1267 struct vnode *tdvp = ap->a_tdvp; 1268 struct vnode *tvp = ap->a_tvp; 1269 1270 if (fdvp->v_op == union_vnodeop_p) { /* always true */ 1271 struct union_node *un = VTOUNION(fdvp); 1272 if (un->un_uppervp == NULLVP) { 1273 /* 1274 * this should never happen in normal 1275 * operation but might if there was 1276 * a problem creating the top-level shadow 1277 * directory. 1278 */ 1279 error = EXDEV; 1280 goto bad; 1281 } 1282 1283 fdvp = un->un_uppervp; 1284 vref(fdvp); 1285 } 1286 1287 if (fvp->v_op == union_vnodeop_p) { /* always true */ 1288 struct union_node *un = VTOUNION(fvp); 1289 if (un->un_uppervp == NULLVP) { 1290 /* XXX: should do a copyup */ 1291 error = EXDEV; 1292 goto bad; 1293 } 1294 1295 if (un->un_lowervp != NULLVP) 1296 ap->a_fcnp->cn_flags |= DOWHITEOUT; 1297 1298 fvp = un->un_uppervp; 1299 vref(fvp); 1300 } 1301 1302 if (tdvp->v_op == union_vnodeop_p) { 1303 struct union_node *un = VTOUNION(tdvp); 1304 if (un->un_uppervp == NULLVP) { 1305 /* 1306 * this should never happen in normal 1307 * operation but might if there was 1308 * a problem creating the top-level shadow 1309 * directory. 1310 */ 1311 error = EXDEV; 1312 goto bad; 1313 } 1314 1315 tdvp = un->un_uppervp; 1316 vref(tdvp); 1317 un->un_flags |= UN_KLOCK; 1318 vput(ap->a_tdvp); 1319 } 1320 1321 if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) { 1322 struct union_node *un = VTOUNION(tvp); 1323 1324 tvp = un->un_uppervp; 1325 if (tvp != NULLVP) { 1326 vref(tvp); 1327 un->un_flags |= UN_KLOCK; 1328 } 1329 vput(ap->a_tvp); 1330 } 1331 1332 error = VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp); 1333 goto out; 1334 1335bad: 1336 vput(tdvp); 1337 if (tvp != NULLVP) 1338 vput(tvp); 1339 vrele(fdvp); 1340 vrele(fvp); 1341 1342out: 1343 if (fdvp != ap->a_fdvp) { 1344 vrele(ap->a_fdvp); 1345 } 1346 if (fvp != ap->a_fvp) { 1347 vrele(ap->a_fvp); 1348 } 1349 return (error); 1350} 1351 1352int 1353union_mkdir(void *v) 1354{ 1355 struct vop_mkdir_v3_args /* { 1356 struct vnode *a_dvp; 1357 struct vnode **a_vpp; 1358 struct componentname *a_cnp; 1359 struct vattr *a_vap; 1360 } */ *ap = v; 1361 struct union_node *un = VTOUNION(ap->a_dvp); 1362 struct vnode *dvp = un->un_uppervp; 1363 struct componentname *cnp = ap->a_cnp; 1364 1365 if (dvp != NULLVP) { 1366 int error; 1367 struct vnode *vp; 1368 1369 error = VOP_MKDIR(dvp, &vp, cnp, ap->a_vap); 1370 if (error) { 1371 vrele(ap->a_dvp); 1372 return (error); 1373 } 1374 1375 /* XXX: lock upper node until lookup returns unlocked nodes. */ 1376 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1377 error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, 1378 NULLVP, cnp, vp, NULLVP, 1); 1379 VOP_UNLOCK(vp); 1380 if (error) 1381 vrele(vp); 1382 return (error); 1383 } 1384 1385 return (EROFS); 1386} 1387 1388int 1389union_rmdir(void *v) 1390{ 1391 struct vop_rmdir_args /* { 1392 struct vnode *a_dvp; 1393 struct vnode *a_vp; 1394 struct componentname *a_cnp; 1395 } */ *ap = v; 1396 int error; 1397 struct union_node *dun = VTOUNION(ap->a_dvp); 1398 struct union_node *un = VTOUNION(ap->a_vp); 1399 struct componentname *cnp = ap->a_cnp; 1400 1401 if (dun->un_uppervp == NULLVP) 1402 panic("union rmdir: null upper vnode"); 1403 1404 error = union_check_rmdir(un, cnp->cn_cred); 1405 if (error) { 1406 vput(ap->a_dvp); 1407 vput(ap->a_vp); 1408 return error; 1409 } 1410 1411 if (un->un_uppervp != NULLVP) { 1412 struct vnode *dvp = dun->un_uppervp; 1413 struct vnode *vp = un->un_uppervp; 1414 1415 vref(dvp); 1416 dun->un_flags |= UN_KLOCK; 1417 vput(ap->a_dvp); 1418 vref(vp); 1419 un->un_flags |= UN_KLOCK; 1420 vput(ap->a_vp); 1421 1422 if (union_dowhiteout(un, cnp->cn_cred)) 1423 cnp->cn_flags |= DOWHITEOUT; 1424 error = VOP_RMDIR(dvp, vp, ap->a_cnp); 1425 if (!error) 1426 union_removed_upper(un); 1427 } else { 1428 error = union_mkwhiteout( 1429 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1430 dun->un_uppervp, ap->a_cnp, un); 1431 vput(ap->a_dvp); 1432 vput(ap->a_vp); 1433 } 1434 1435 return (error); 1436} 1437 1438int 1439union_symlink(void *v) 1440{ 1441 struct vop_symlink_v3_args /* { 1442 struct vnode *a_dvp; 1443 struct vnode **a_vpp; 1444 struct componentname *a_cnp; 1445 struct vattr *a_vap; 1446 char *a_target; 1447 } */ *ap = v; 1448 struct union_node *un = VTOUNION(ap->a_dvp); 1449 struct vnode *dvp = un->un_uppervp; 1450 struct componentname *cnp = ap->a_cnp; 1451 1452 if (dvp != NULLVP) { 1453 int error; 1454 1455 error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap, 1456 ap->a_target); 1457 return (error); 1458 } 1459 1460 return (EROFS); 1461} 1462 1463/* 1464 * union_readdir works in concert with getdirentries and 1465 * readdir(3) to provide a list of entries in the unioned 1466 * directories. getdirentries is responsible for walking 1467 * down the union stack. readdir(3) is responsible for 1468 * eliminating duplicate names from the returned data stream. 1469 */ 1470int 1471union_readdir(void *v) 1472{ 1473 struct vop_readdir_args /* { 1474 struct vnodeop_desc *a_desc; 1475 struct vnode *a_vp; 1476 struct uio *a_uio; 1477 kauth_cred_t a_cred; 1478 int *a_eofflag; 1479 u_long *a_cookies; 1480 int a_ncookies; 1481 } */ *ap = v; 1482 struct union_node *un = VTOUNION(ap->a_vp); 1483 struct vnode *uvp = un->un_uppervp; 1484 1485 if (uvp == NULLVP) 1486 return (0); 1487 1488 ap->a_vp = uvp; 1489 return (VCALL(uvp, VOFFSET(vop_readdir), ap)); 1490} 1491 1492int 1493union_readlink(void *v) 1494{ 1495 struct vop_readlink_args /* { 1496 struct vnode *a_vp; 1497 struct uio *a_uio; 1498 kauth_cred_t a_cred; 1499 } */ *ap = v; 1500 int error; 1501 struct vnode *vp = OTHERVP(ap->a_vp); 1502 int dolock = (vp == LOWERVP(ap->a_vp)); 1503 1504 if (dolock) 1505 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1506 ap->a_vp = vp; 1507 error = VCALL(vp, VOFFSET(vop_readlink), ap); 1508 if (dolock) 1509 VOP_UNLOCK(vp); 1510 1511 return (error); 1512} 1513 1514int 1515union_abortop(void *v) 1516{ 1517 struct vop_abortop_args /* { 1518 struct vnode *a_dvp; 1519 struct componentname *a_cnp; 1520 } */ *ap = v; 1521 1522 KASSERT(UPPERVP(ap->a_dvp) != NULL); 1523 1524 ap->a_dvp = UPPERVP(ap->a_dvp); 1525 return VCALL(ap->a_dvp, VOFFSET(vop_abortop), ap); 1526} 1527 1528int 1529union_inactive(void *v) 1530{ 1531 struct vop_inactive_args /* { 1532 const struct vnodeop_desc *a_desc; 1533 struct vnode *a_vp; 1534 bool *a_recycle; 1535 } */ *ap = v; 1536 struct vnode *vp = ap->a_vp; 1537 struct union_node *un = VTOUNION(vp); 1538 struct vnode **vpp; 1539 1540 /* 1541 * Do nothing (and _don't_ bypass). 1542 * Wait to vrele lowervp until reclaim, 1543 * so that until then our union_node is in the 1544 * cache and reusable. 1545 * 1546 * NEEDSWORK: Someday, consider inactive'ing 1547 * the lowervp and then trying to reactivate it 1548 * with capabilities (v_id) 1549 * like they do in the name lookup cache code. 1550 * That's too much work for now. 1551 */ 1552 1553 if (un->un_dircache != 0) { 1554 for (vpp = un->un_dircache; *vpp != NULLVP; vpp++) 1555 vrele(*vpp); 1556 free(un->un_dircache, M_TEMP); 1557 un->un_dircache = 0; 1558 } 1559 1560 *ap->a_recycle = ((un->un_cflags & UN_CACHED) == 0); 1561 VOP_UNLOCK(vp); 1562 1563 return (0); 1564} 1565 1566int 1567union_reclaim(void *v) 1568{ 1569 struct vop_reclaim_args /* { 1570 struct vnode *a_vp; 1571 } */ *ap = v; 1572 1573 union_freevp(ap->a_vp); 1574 1575 return (0); 1576} 1577 1578int 1579union_lock(void *v) 1580{ 1581 struct vop_lock_args /* { 1582 struct vnode *a_vp; 1583 int a_flags; 1584 } */ *ap = v; 1585 struct vnode *vp; 1586 struct union_node *un; 1587 int error; 1588 1589 un = VTOUNION(ap->a_vp); 1590 mutex_enter(&un->un_lock); 1591 for (;;) { 1592 vp = LOCKVP(ap->a_vp); 1593 mutex_exit(&un->un_lock); 1594 if (vp == ap->a_vp) 1595 error = genfs_lock(ap); 1596 else 1597 error = VOP_LOCK(vp, ap->a_flags); 1598 if (error != 0) 1599 return error; 1600 mutex_enter(&un->un_lock); 1601 if (vp == LOCKVP(ap->a_vp)) 1602 break; 1603 if (vp == ap->a_vp) 1604 genfs_unlock(ap); 1605 else 1606 VOP_UNLOCK(vp); 1607 } 1608 KASSERT((un->un_flags & UN_KLOCK) == 0); 1609 mutex_exit(&un->un_lock); 1610 1611 return error; 1612} 1613 1614/* 1615 * When operations want to vput() a union node yet retain a lock on 1616 * the upper vnode (say, to do some further operations like link(), 1617 * mkdir(), ...), they set UN_KLOCK on the union node, then call 1618 * vput() which calls VOP_UNLOCK() and comes here. union_unlock() 1619 * unlocks the union node (leaving the upper vnode alone), clears the 1620 * KLOCK flag, and then returns to vput(). The caller then does whatever 1621 * is left to do with the upper vnode, and ensures that it gets unlocked. 1622 * 1623 * If UN_KLOCK isn't set, then the upper vnode is unlocked here. 1624 */ 1625int 1626union_unlock(void *v) 1627{ 1628 struct vop_unlock_args /* { 1629 struct vnode *a_vp; 1630 int a_flags; 1631 } */ *ap = v; 1632 struct vnode *vp; 1633 struct union_node *un; 1634 1635 un = VTOUNION(ap->a_vp); 1636 vp = LOCKVP(ap->a_vp); 1637 if ((un->un_flags & UN_KLOCK) == UN_KLOCK) { 1638 KASSERT(vp != ap->a_vp); 1639 un->un_flags &= ~UN_KLOCK; 1640 return 0; 1641 } 1642 if (vp == ap->a_vp) 1643 genfs_unlock(ap); 1644 else 1645 VOP_UNLOCK(vp); 1646 1647 return 0; 1648} 1649 1650int 1651union_bmap(void *v) 1652{ 1653 struct vop_bmap_args /* { 1654 struct vnode *a_vp; 1655 daddr_t a_bn; 1656 struct vnode **a_vpp; 1657 daddr_t *a_bnp; 1658 int *a_runp; 1659 } */ *ap = v; 1660 int error; 1661 struct vnode *vp = OTHERVP(ap->a_vp); 1662 int dolock = (vp == LOWERVP(ap->a_vp)); 1663 1664 if (dolock) 1665 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1666 ap->a_vp = vp; 1667 error = VCALL(vp, VOFFSET(vop_bmap), ap); 1668 if (dolock) 1669 VOP_UNLOCK(vp); 1670 1671 return (error); 1672} 1673 1674int 1675union_print(void *v) 1676{ 1677 struct vop_print_args /* { 1678 struct vnode *a_vp; 1679 } */ *ap = v; 1680 struct vnode *vp = ap->a_vp; 1681 1682 printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n", 1683 vp, UPPERVP(vp), LOWERVP(vp)); 1684 if (UPPERVP(vp) != NULLVP) 1685 vprint("union: upper", UPPERVP(vp)); 1686 if (LOWERVP(vp) != NULLVP) 1687 vprint("union: lower", LOWERVP(vp)); 1688 if (VTOUNION(vp)->un_dircache) { 1689 struct vnode **vpp; 1690 for (vpp = VTOUNION(vp)->un_dircache; *vpp != NULLVP; vpp++) 1691 vprint("dircache:", *vpp); 1692 } 1693 1694 return (0); 1695} 1696 1697int 1698union_islocked(void *v) 1699{ 1700 struct vop_islocked_args /* { 1701 struct vnode *a_vp; 1702 } */ *ap = v; 1703 struct vnode *vp; 1704 struct union_node *un; 1705 1706 un = VTOUNION(ap->a_vp); 1707 mutex_enter(&un->un_lock); 1708 vp = LOCKVP(ap->a_vp); 1709 mutex_exit(&un->un_lock); 1710 1711 if (vp == ap->a_vp) 1712 return genfs_islocked(ap); 1713 else 1714 return VOP_ISLOCKED(vp); 1715} 1716 1717int 1718union_pathconf(void *v) 1719{ 1720 struct vop_pathconf_args /* { 1721 struct vnode *a_vp; 1722 int a_name; 1723 int *a_retval; 1724 } */ *ap = v; 1725 int error; 1726 struct vnode *vp = OTHERVP(ap->a_vp); 1727 int dolock = (vp == LOWERVP(ap->a_vp)); 1728 1729 if (dolock) 1730 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1731 ap->a_vp = vp; 1732 error = VCALL(vp, VOFFSET(vop_pathconf), ap); 1733 if (dolock) 1734 VOP_UNLOCK(vp); 1735 1736 return (error); 1737} 1738 1739int 1740union_advlock(void *v) 1741{ 1742 struct vop_advlock_args /* { 1743 struct vnode *a_vp; 1744 void *a_id; 1745 int a_op; 1746 struct flock *a_fl; 1747 int a_flags; 1748 } */ *ap = v; 1749 struct vnode *ovp = OTHERVP(ap->a_vp); 1750 1751 ap->a_vp = ovp; 1752 return (VCALL(ovp, VOFFSET(vop_advlock), ap)); 1753} 1754 1755int 1756union_strategy(void *v) 1757{ 1758 struct vop_strategy_args /* { 1759 struct vnode *a_vp; 1760 struct buf *a_bp; 1761 } */ *ap = v; 1762 struct vnode *ovp = OTHERVP(ap->a_vp); 1763 struct buf *bp = ap->a_bp; 1764 1765 KASSERT(ovp != NULLVP); 1766 if (!NODE_IS_SPECIAL(ovp)) 1767 KASSERT((bp->b_flags & B_READ) || ovp != LOWERVP(bp->b_vp)); 1768 1769 return (VOP_STRATEGY(ovp, bp)); 1770} 1771 1772int 1773union_bwrite(void *v) 1774{ 1775 struct vop_bwrite_args /* { 1776 struct vnode *a_vp; 1777 struct buf *a_bp; 1778 } */ *ap = v; 1779 struct vnode *ovp = OTHERVP(ap->a_vp); 1780 struct buf *bp = ap->a_bp; 1781 1782 KASSERT(ovp != NULLVP); 1783 if (!NODE_IS_SPECIAL(ovp)) 1784 KASSERT((bp->b_flags & B_READ) || ovp != LOWERVP(bp->b_vp)); 1785 1786 return (VOP_BWRITE(ovp, bp)); 1787} 1788 1789int 1790union_getpages(void *v) 1791{ 1792 struct vop_getpages_args /* { 1793 struct vnode *a_vp; 1794 voff_t a_offset; 1795 struct vm_page **a_m; 1796 int *a_count; 1797 int a_centeridx; 1798 vm_prot_t a_access_type; 1799 int a_advice; 1800 int a_flags; 1801 } */ *ap = v; 1802 struct vnode *vp = ap->a_vp; 1803 1804 KASSERT(mutex_owned(vp->v_interlock)); 1805 1806 if (ap->a_flags & PGO_LOCKED) { 1807 return EBUSY; 1808 } 1809 ap->a_vp = OTHERVP(vp); 1810 KASSERT(vp->v_interlock == ap->a_vp->v_interlock); 1811 1812 /* Just pass the request on to the underlying layer. */ 1813 return VCALL(ap->a_vp, VOFFSET(vop_getpages), ap); 1814} 1815 1816int 1817union_putpages(void *v) 1818{ 1819 struct vop_putpages_args /* { 1820 struct vnode *a_vp; 1821 voff_t a_offlo; 1822 voff_t a_offhi; 1823 int a_flags; 1824 } */ *ap = v; 1825 struct vnode *vp = ap->a_vp; 1826 1827 KASSERT(mutex_owned(vp->v_interlock)); 1828 1829 ap->a_vp = OTHERVP(vp); 1830 KASSERT(vp->v_interlock == ap->a_vp->v_interlock); 1831 1832 if (ap->a_flags & PGO_RECLAIM) { 1833 mutex_exit(vp->v_interlock); 1834 return 0; 1835 } 1836 1837 /* Just pass the request on to the underlying layer. */ 1838 return VCALL(ap->a_vp, VOFFSET(vop_putpages), ap); 1839} 1840 1841int 1842union_kqfilter(void *v) 1843{ 1844 struct vop_kqfilter_args /* { 1845 struct vnode *a_vp; 1846 struct knote *a_kn; 1847 } */ *ap = v; 1848 int error; 1849 1850 /* 1851 * We watch either the upper layer file (if it already exists), 1852 * or the lower layer one. If there is lower layer file only 1853 * at this moment, we will keep watching that lower layer file 1854 * even if upper layer file would be created later on. 1855 */ 1856 if (UPPERVP(ap->a_vp)) 1857 error = VOP_KQFILTER(UPPERVP(ap->a_vp), ap->a_kn); 1858 else if (LOWERVP(ap->a_vp)) 1859 error = VOP_KQFILTER(LOWERVP(ap->a_vp), ap->a_kn); 1860 else { 1861 /* panic? */ 1862 error = EOPNOTSUPP; 1863 } 1864 1865 return (error); 1866} 1867