union_vnops.c revision 1.79
1 /* $NetBSD: union_vnops.c,v 1.79 2021/10/20 03:08:17 thorpej 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 1.79 2021/10/20 03:08:17 thorpej 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 96 int union_parsepath(void *); 97 int union_lookup(void *); 98 int union_create(void *); 99 int union_whiteout(void *); 100 int union_mknod(void *); 101 int union_open(void *); 102 int union_close(void *); 103 int union_access(void *); 104 int union_getattr(void *); 105 int union_setattr(void *); 106 int union_read(void *); 107 int union_write(void *); 108 int union_ioctl(void *); 109 int union_poll(void *); 110 int union_revoke(void *); 111 int union_mmap(void *); 112 int union_fsync(void *); 113 int union_seek(void *); 114 int union_remove(void *); 115 int union_link(void *); 116 int union_rename(void *); 117 int union_mkdir(void *); 118 int union_rmdir(void *); 119 int union_symlink(void *); 120 int union_readdir(void *); 121 int union_readlink(void *); 122 int union_abortop(void *); 123 int union_inactive(void *); 124 int union_reclaim(void *); 125 int union_lock(void *); 126 int union_unlock(void *); 127 int union_bmap(void *); 128 int union_print(void *); 129 int union_islocked(void *); 130 int union_pathconf(void *); 131 int union_advlock(void *); 132 int union_strategy(void *); 133 int union_bwrite(void *); 134 int union_getpages(void *); 135 int union_putpages(void *); 136 int union_kqfilter(void *); 137 138 static int union_lookup1(struct vnode *, struct vnode **, 139 struct vnode **, struct componentname *); 140 141 142 /* 143 * Global vfs data structures 144 */ 145 int (**union_vnodeop_p)(void *); 146 const struct vnodeopv_entry_desc union_vnodeop_entries[] = { 147 { &vop_default_desc, vn_default_error }, 148 { &vop_parsepath_desc, union_parsepath }, /* parsepath */ 149 { &vop_lookup_desc, union_lookup }, /* lookup */ 150 { &vop_create_desc, union_create }, /* create */ 151 { &vop_whiteout_desc, union_whiteout }, /* whiteout */ 152 { &vop_mknod_desc, union_mknod }, /* mknod */ 153 { &vop_open_desc, union_open }, /* open */ 154 { &vop_close_desc, union_close }, /* close */ 155 { &vop_access_desc, union_access }, /* access */ 156 { &vop_accessx_desc, genfs_accessx }, /* accessx */ 157 { &vop_getattr_desc, union_getattr }, /* getattr */ 158 { &vop_setattr_desc, union_setattr }, /* setattr */ 159 { &vop_read_desc, union_read }, /* read */ 160 { &vop_write_desc, union_write }, /* write */ 161 { &vop_fallocate_desc, genfs_eopnotsupp }, /* fallocate */ 162 { &vop_fdiscard_desc, genfs_eopnotsupp }, /* fdiscard */ 163 { &vop_ioctl_desc, union_ioctl }, /* ioctl */ 164 { &vop_poll_desc, union_poll }, /* select */ 165 { &vop_revoke_desc, union_revoke }, /* revoke */ 166 { &vop_mmap_desc, union_mmap }, /* mmap */ 167 { &vop_fsync_desc, union_fsync }, /* fsync */ 168 { &vop_seek_desc, union_seek }, /* seek */ 169 { &vop_remove_desc, union_remove }, /* remove */ 170 { &vop_link_desc, union_link }, /* link */ 171 { &vop_rename_desc, union_rename }, /* rename */ 172 { &vop_mkdir_desc, union_mkdir }, /* mkdir */ 173 { &vop_rmdir_desc, union_rmdir }, /* rmdir */ 174 { &vop_symlink_desc, union_symlink }, /* symlink */ 175 { &vop_readdir_desc, union_readdir }, /* readdir */ 176 { &vop_readlink_desc, union_readlink }, /* readlink */ 177 { &vop_abortop_desc, union_abortop }, /* abortop */ 178 { &vop_inactive_desc, union_inactive }, /* inactive */ 179 { &vop_reclaim_desc, union_reclaim }, /* reclaim */ 180 { &vop_lock_desc, union_lock }, /* lock */ 181 { &vop_unlock_desc, union_unlock }, /* unlock */ 182 { &vop_bmap_desc, union_bmap }, /* bmap */ 183 { &vop_strategy_desc, union_strategy }, /* strategy */ 184 { &vop_bwrite_desc, union_bwrite }, /* bwrite */ 185 { &vop_print_desc, union_print }, /* print */ 186 { &vop_islocked_desc, union_islocked }, /* islocked */ 187 { &vop_pathconf_desc, union_pathconf }, /* pathconf */ 188 { &vop_advlock_desc, union_advlock }, /* advlock */ 189 { &vop_getpages_desc, union_getpages }, /* getpages */ 190 { &vop_putpages_desc, union_putpages }, /* putpages */ 191 { &vop_kqfilter_desc, union_kqfilter }, /* kqfilter */ 192 { NULL, NULL } 193 }; 194 const struct vnodeopv_desc union_vnodeop_opv_desc = 195 { &union_vnodeop_p, union_vnodeop_entries }; 196 197 #define NODE_IS_SPECIAL(vp) \ 198 ((vp)->v_type == VBLK || (vp)->v_type == VCHR || \ 199 (vp)->v_type == VSOCK || (vp)->v_type == VFIFO) 200 201 int 202 union_parsepath(void *v) 203 { 204 struct vop_parsepath_args /* { 205 struct vnode *a_dvp; 206 const char *a_name; 207 size_t *a_retval; 208 } */ *ap = v; 209 struct vnode *upperdvp, *lowerdvp; 210 size_t upper, lower; 211 int error; 212 213 upperdvp = UPPERVP(ap->a_dvp); 214 lowerdvp = LOWERVP(ap->a_dvp); 215 216 if (upperdvp != NULLVP) { 217 error = VOP_PARSEPATH(upperdvp, ap->a_name, &upper); 218 if (error) { 219 return error; 220 } 221 } else { 222 upper = 0; 223 } 224 225 if (lowerdvp != NULLVP) { 226 error = VOP_PARSEPATH(lowerdvp, ap->a_name, &lower); 227 if (error) { 228 return error; 229 } 230 } else { 231 lower = 0; 232 } 233 234 if (upper == 0 && lower == 0) { 235 panic("%s: missing both layers", __func__); 236 } 237 238 /* 239 * If they're different, use the larger one. This is not a 240 * comprehensive solution, but it's sufficient for the 241 * non-default cases of parsepath that currently exist. 242 */ 243 *ap->a_retval = MAX(upper, lower); 244 return 0; 245 } 246 247 static int 248 union_lookup1(struct vnode *udvp, struct vnode **dvpp, struct vnode **vpp, 249 struct componentname *cnp) 250 { 251 int error; 252 struct vnode *tdvp; 253 struct vnode *dvp; 254 struct mount *mp; 255 256 dvp = *dvpp; 257 258 /* 259 * If stepping up the directory tree, check for going 260 * back across the mount point, in which case do what 261 * lookup would do by stepping back down the mount 262 * hierarchy. 263 */ 264 if (cnp->cn_flags & ISDOTDOT) { 265 while ((dvp != udvp) && (dvp->v_vflag & VV_ROOT)) { 266 /* 267 * Don't do the NOCROSSMOUNT check 268 * at this level. By definition, 269 * union fs deals with namespaces, not 270 * filesystems. 271 */ 272 tdvp = dvp; 273 *dvpp = dvp = dvp->v_mount->mnt_vnodecovered; 274 VOP_UNLOCK(tdvp); 275 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 276 } 277 } 278 279 error = VOP_LOOKUP(dvp, &tdvp, cnp); 280 if (error) 281 return (error); 282 if (dvp != tdvp) { 283 if (cnp->cn_flags & ISDOTDOT) 284 VOP_UNLOCK(dvp); 285 error = vn_lock(tdvp, LK_EXCLUSIVE); 286 if (cnp->cn_flags & ISDOTDOT) 287 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 288 if (error) { 289 vrele(tdvp); 290 return error; 291 } 292 dvp = tdvp; 293 } 294 295 /* 296 * Lastly check if the current node is a mount point in 297 * which case walk up the mount hierarchy making sure not to 298 * bump into the root of the mount tree (ie. dvp != udvp). 299 */ 300 while (dvp != udvp && (dvp->v_type == VDIR) && 301 (mp = dvp->v_mountedhere)) { 302 if (vfs_busy(mp)) 303 continue; 304 vput(dvp); 305 error = VFS_ROOT(mp, LK_EXCLUSIVE, &tdvp); 306 vfs_unbusy(mp); 307 if (error) { 308 return (error); 309 } 310 dvp = tdvp; 311 } 312 313 *vpp = dvp; 314 return (0); 315 } 316 317 int 318 union_lookup(void *v) 319 { 320 struct vop_lookup_v2_args /* { 321 struct vnodeop_desc *a_desc; 322 struct vnode *a_dvp; 323 struct vnode **a_vpp; 324 struct componentname *a_cnp; 325 } */ *ap = v; 326 int error; 327 int uerror, lerror; 328 struct vnode *uppervp, *lowervp; 329 struct vnode *upperdvp, *lowerdvp; 330 struct vnode *dvp = ap->a_dvp; 331 struct union_node *dun = VTOUNION(dvp); 332 struct componentname *cnp = ap->a_cnp; 333 struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); 334 kauth_cred_t saved_cred = NULL; 335 int iswhiteout; 336 struct vattr va; 337 338 #ifdef notyet 339 if (cnp->cn_namelen == 3 && 340 cnp->cn_nameptr[2] == '.' && 341 cnp->cn_nameptr[1] == '.' && 342 cnp->cn_nameptr[0] == '.') { 343 dvp = *ap->a_vpp = LOWERVP(ap->a_dvp); 344 if (dvp == NULLVP) 345 return (ENOENT); 346 vref(dvp); 347 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 348 return (0); 349 } 350 #endif 351 352 if ((cnp->cn_flags & ISLASTCN) && 353 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 354 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 355 return (EROFS); 356 357 start: 358 upperdvp = dun->un_uppervp; 359 lowerdvp = dun->un_lowervp; 360 uppervp = NULLVP; 361 lowervp = NULLVP; 362 iswhiteout = 0; 363 364 /* 365 * do the lookup in the upper level. 366 * if that level comsumes additional pathnames, 367 * then assume that something special is going 368 * on and just return that vnode. 369 */ 370 if (upperdvp != NULLVP) { 371 uerror = union_lookup1(um->um_uppervp, &upperdvp, 372 &uppervp, cnp); 373 if (uerror == ENOENT || uerror == EJUSTRETURN) { 374 if (cnp->cn_flags & ISWHITEOUT) { 375 iswhiteout = 1; 376 } else if (lowerdvp != NULLVP) { 377 lerror = VOP_GETATTR(upperdvp, &va, 378 cnp->cn_cred); 379 if (lerror == 0 && (va.va_flags & OPAQUE)) 380 iswhiteout = 1; 381 } 382 } 383 } else { 384 uerror = ENOENT; 385 } 386 387 /* 388 * in a similar way to the upper layer, do the lookup 389 * in the lower layer. this time, if there is some 390 * component magic going on, then vput whatever we got 391 * back from the upper layer and return the lower vnode 392 * instead. 393 */ 394 if (lowerdvp != NULLVP && !iswhiteout) { 395 int nameiop; 396 397 vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY); 398 399 /* 400 * Only do a LOOKUP on the bottom node, since 401 * we won't be making changes to it anyway. 402 */ 403 nameiop = cnp->cn_nameiop; 404 cnp->cn_nameiop = LOOKUP; 405 if (um->um_op == UNMNT_BELOW) { 406 saved_cred = cnp->cn_cred; 407 cnp->cn_cred = um->um_cred; 408 } 409 410 /* 411 * we shouldn't have to worry about locking interactions 412 * between the lower layer and our union layer (w.r.t. 413 * `..' processing) because we don't futz with lowervp 414 * locks in the union-node instantiation code path. 415 */ 416 lerror = union_lookup1(um->um_lowervp, &lowerdvp, 417 &lowervp, cnp); 418 if (um->um_op == UNMNT_BELOW) 419 cnp->cn_cred = saved_cred; 420 cnp->cn_nameiop = nameiop; 421 422 if (lowervp != lowerdvp) 423 VOP_UNLOCK(lowerdvp); 424 } else { 425 lerror = ENOENT; 426 if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) { 427 lowervp = LOWERVP(dun->un_pvp); 428 if (lowervp != NULLVP) { 429 vref(lowervp); 430 vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY); 431 lerror = 0; 432 } 433 } 434 } 435 436 /* 437 * EJUSTRETURN is used by underlying filesystems to indicate that 438 * a directory modification op was started successfully. 439 * This will only happen in the upper layer, since 440 * the lower layer only does LOOKUPs. 441 * If this union is mounted read-only, bounce it now. 442 */ 443 444 if ((uerror == EJUSTRETURN) && (cnp->cn_flags & ISLASTCN) && 445 (dvp->v_mount->mnt_flag & MNT_RDONLY) && 446 ((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME))) 447 uerror = EROFS; 448 449 /* 450 * at this point, we have uerror and lerror indicating 451 * possible errors with the lookups in the upper and lower 452 * layers. additionally, uppervp and lowervp are (locked) 453 * references to existing vnodes in the upper and lower layers. 454 * 455 * there are now three cases to consider. 456 * 1. if both layers returned an error, then return whatever 457 * error the upper layer generated. 458 * 459 * 2. if the top layer failed and the bottom layer succeeded 460 * then two subcases occur. 461 * a. the bottom vnode is not a directory, in which 462 * case just return a new union vnode referencing 463 * an empty top layer and the existing bottom layer. 464 * b. the bottom vnode is a directory, in which case 465 * create a new directory in the top-level and 466 * continue as in case 3. 467 * 468 * 3. if the top layer succeeded then return a new union 469 * vnode referencing whatever the new top layer and 470 * whatever the bottom layer returned. 471 */ 472 473 *ap->a_vpp = NULLVP; 474 475 476 /* case 1. */ 477 if ((uerror != 0) && (lerror != 0)) { 478 return (uerror); 479 } 480 481 /* case 2. */ 482 if (uerror != 0 /* && (lerror == 0) */ ) { 483 if (lowervp->v_type == VDIR) { /* case 2b. */ 484 /* 485 * We may be racing another process to make the 486 * upper-level shadow directory. Be careful with 487 * locks/etc! 488 * If we have to create a shadow directory and want 489 * to commit the node we have to restart the lookup 490 * to get the componentname right. 491 */ 492 if (upperdvp) { 493 VOP_UNLOCK(upperdvp); 494 uerror = union_mkshadow(um, upperdvp, cnp, 495 &uppervp); 496 vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY); 497 if (uerror == 0 && cnp->cn_nameiop != LOOKUP) { 498 vrele(uppervp); 499 if (lowervp != NULLVP) 500 vput(lowervp); 501 goto start; 502 } 503 } 504 if (uerror) { 505 if (lowervp != NULLVP) { 506 vput(lowervp); 507 lowervp = NULLVP; 508 } 509 return (uerror); 510 } 511 } 512 } else { /* uerror == 0 */ 513 if (uppervp != upperdvp) 514 VOP_UNLOCK(uppervp); 515 } 516 517 if (lowervp != NULLVP) 518 VOP_UNLOCK(lowervp); 519 520 error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, 521 uppervp, lowervp, 1); 522 523 if (error) { 524 if (uppervp != NULLVP) 525 vrele(uppervp); 526 if (lowervp != NULLVP) 527 vrele(lowervp); 528 return error; 529 } 530 531 return 0; 532 } 533 534 int 535 union_create(void *v) 536 { 537 struct vop_create_v3_args /* { 538 struct vnode *a_dvp; 539 struct vnode **a_vpp; 540 struct componentname *a_cnp; 541 struct vattr *a_vap; 542 } */ *ap = v; 543 struct union_node *un = VTOUNION(ap->a_dvp); 544 struct vnode *dvp = un->un_uppervp; 545 struct componentname *cnp = ap->a_cnp; 546 547 if (dvp != NULLVP) { 548 int error; 549 struct vnode *vp; 550 struct mount *mp; 551 552 mp = ap->a_dvp->v_mount; 553 554 vp = NULL; 555 error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap); 556 if (error) 557 return (error); 558 559 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp, 560 NULLVP, 1); 561 if (error) 562 vrele(vp); 563 return (error); 564 } 565 566 return (EROFS); 567 } 568 569 int 570 union_whiteout(void *v) 571 { 572 struct vop_whiteout_args /* { 573 struct vnode *a_dvp; 574 struct componentname *a_cnp; 575 int a_flags; 576 } */ *ap = v; 577 struct union_node *un = VTOUNION(ap->a_dvp); 578 struct componentname *cnp = ap->a_cnp; 579 580 if (un->un_uppervp == NULLVP) 581 return (EOPNOTSUPP); 582 583 return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags)); 584 } 585 586 int 587 union_mknod(void *v) 588 { 589 struct vop_mknod_v3_args /* { 590 struct vnode *a_dvp; 591 struct vnode **a_vpp; 592 struct componentname *a_cnp; 593 struct vattr *a_vap; 594 } */ *ap = v; 595 struct union_node *un = VTOUNION(ap->a_dvp); 596 struct vnode *dvp = un->un_uppervp; 597 struct componentname *cnp = ap->a_cnp; 598 599 if (dvp != NULLVP) { 600 int error; 601 struct vnode *vp; 602 struct mount *mp; 603 604 mp = ap->a_dvp->v_mount; 605 error = VOP_MKNOD(dvp, &vp, cnp, ap->a_vap); 606 if (error) 607 return (error); 608 609 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, 610 cnp, vp, NULLVP, 1); 611 if (error) 612 vrele(vp); 613 return (error); 614 } 615 616 return (EROFS); 617 } 618 619 int 620 union_open(void *v) 621 { 622 struct vop_open_args /* { 623 struct vnodeop_desc *a_desc; 624 struct vnode *a_vp; 625 int a_mode; 626 kauth_cred_t a_cred; 627 } */ *ap = v; 628 struct union_node *un = VTOUNION(ap->a_vp); 629 struct vnode *tvp; 630 int mode = ap->a_mode; 631 kauth_cred_t cred = ap->a_cred; 632 struct lwp *l = curlwp; 633 int error; 634 635 /* 636 * If there is an existing upper vp then simply open that. 637 */ 638 tvp = un->un_uppervp; 639 if (tvp == NULLVP) { 640 /* 641 * If the lower vnode is being opened for writing, then 642 * copy the file contents to the upper vnode and open that, 643 * otherwise can simply open the lower vnode. 644 */ 645 tvp = un->un_lowervp; 646 if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) { 647 error = union_copyup(un, (mode&O_TRUNC) == 0, cred, l); 648 if (error == 0) 649 error = VOP_OPEN(un->un_uppervp, mode, cred); 650 if (error == 0) { 651 mutex_enter(un->un_uppervp->v_interlock); 652 un->un_uppervp->v_writecount++; 653 mutex_exit(un->un_uppervp->v_interlock); 654 } 655 return (error); 656 } 657 658 /* 659 * Just open the lower vnode, but check for nodev mount flag 660 */ 661 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 662 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 663 return ENXIO; 664 un->un_openl++; 665 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); 666 error = VOP_OPEN(tvp, mode, cred); 667 VOP_UNLOCK(tvp); 668 669 return (error); 670 } 671 /* 672 * Just open the upper vnode, checking for nodev mount flag first 673 */ 674 if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && 675 (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) 676 return ENXIO; 677 678 error = VOP_OPEN(tvp, mode, cred); 679 if (error == 0 && (ap->a_mode & FWRITE)) { 680 mutex_enter(tvp->v_interlock); 681 tvp->v_writecount++; 682 mutex_exit(tvp->v_interlock); 683 } 684 685 return (error); 686 } 687 688 int 689 union_close(void *v) 690 { 691 struct vop_close_args /* { 692 struct vnode *a_vp; 693 int a_fflag; 694 kauth_cred_t a_cred; 695 } */ *ap = v; 696 struct union_node *un = VTOUNION(ap->a_vp); 697 struct vnode *vp; 698 int error; 699 bool do_lock; 700 701 vp = un->un_uppervp; 702 if (vp != NULLVP) { 703 do_lock = false; 704 } else { 705 KASSERT(un->un_openl > 0); 706 --un->un_openl; 707 vp = un->un_lowervp; 708 do_lock = true; 709 } 710 711 KASSERT(vp != NULLVP); 712 ap->a_vp = vp; 713 if ((ap->a_fflag & FWRITE)) { 714 KASSERT(vp == un->un_uppervp); 715 mutex_enter(vp->v_interlock); 716 vp->v_writecount--; 717 mutex_exit(vp->v_interlock); 718 } 719 if (do_lock) 720 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 721 error = VCALL(vp, VOFFSET(vop_close), ap); 722 if (do_lock) 723 VOP_UNLOCK(vp); 724 725 return error; 726 } 727 728 /* 729 * Check access permission on the union vnode. 730 * The access check being enforced is to check 731 * against both the underlying vnode, and any 732 * copied vnode. This ensures that no additional 733 * file permissions are given away simply because 734 * the user caused an implicit file copy. 735 */ 736 int 737 union_access(void *v) 738 { 739 struct vop_access_args /* { 740 struct vnodeop_desc *a_desc; 741 struct vnode *a_vp; 742 accmode_t a_accmode; 743 kauth_cred_t a_cred; 744 } */ *ap = v; 745 struct vnode *vp = ap->a_vp; 746 struct union_node *un = VTOUNION(vp); 747 int error = EACCES; 748 struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount); 749 750 /* 751 * Disallow write attempts on read-only file systems; 752 * unless the file is a socket, fifo, or a block or 753 * character device resident on the file system. 754 */ 755 if (ap->a_accmode & VWRITE) { 756 switch (vp->v_type) { 757 case VDIR: 758 case VLNK: 759 case VREG: 760 if (vp->v_mount->mnt_flag & MNT_RDONLY) 761 return (EROFS); 762 break; 763 case VBAD: 764 case VBLK: 765 case VCHR: 766 case VSOCK: 767 case VFIFO: 768 case VNON: 769 default: 770 break; 771 } 772 } 773 774 775 if ((vp = un->un_uppervp) != NULLVP) { 776 ap->a_vp = vp; 777 return (VCALL(vp, VOFFSET(vop_access), ap)); 778 } 779 780 if ((vp = un->un_lowervp) != NULLVP) { 781 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 782 ap->a_vp = vp; 783 error = VCALL(vp, VOFFSET(vop_access), ap); 784 if (error == 0) { 785 if (um->um_op == UNMNT_BELOW) { 786 ap->a_cred = um->um_cred; 787 error = VCALL(vp, VOFFSET(vop_access), ap); 788 } 789 } 790 VOP_UNLOCK(vp); 791 if (error) 792 return (error); 793 } 794 795 return (error); 796 } 797 798 /* 799 * We handle getattr only to change the fsid and 800 * track object sizes 801 */ 802 int 803 union_getattr(void *v) 804 { 805 struct vop_getattr_args /* { 806 struct vnode *a_vp; 807 struct vattr *a_vap; 808 kauth_cred_t a_cred; 809 } */ *ap = v; 810 int error; 811 struct union_node *un = VTOUNION(ap->a_vp); 812 struct vnode *vp = un->un_uppervp; 813 struct vattr *vap; 814 struct vattr va; 815 816 817 /* 818 * Some programs walk the filesystem hierarchy by counting 819 * links to directories to avoid stat'ing all the time. 820 * This means the link count on directories needs to be "correct". 821 * The only way to do that is to call getattr on both layers 822 * and fix up the link count. The link count will not necessarily 823 * be accurate but will be large enough to defeat the tree walkers. 824 * 825 * To make life more interesting, some filesystems don't keep 826 * track of link counts in the expected way, and return a 827 * link count of `1' for those directories; if either of the 828 * component directories returns a link count of `1', we return a 1. 829 */ 830 831 vap = ap->a_vap; 832 833 vp = un->un_uppervp; 834 if (vp != NULLVP) { 835 error = VOP_GETATTR(vp, vap, ap->a_cred); 836 if (error) 837 return (error); 838 mutex_enter(&un->un_lock); 839 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 840 } 841 842 if (vp == NULLVP) { 843 vp = un->un_lowervp; 844 } else if (vp->v_type == VDIR) { 845 vp = un->un_lowervp; 846 if (vp != NULLVP) 847 vap = &va; 848 } else { 849 vp = NULLVP; 850 } 851 852 if (vp != NULLVP) { 853 if (vp == un->un_lowervp) 854 vn_lock(vp, LK_SHARED | LK_RETRY); 855 error = VOP_GETATTR(vp, vap, ap->a_cred); 856 if (vp == un->un_lowervp) 857 VOP_UNLOCK(vp); 858 if (error) 859 return (error); 860 mutex_enter(&un->un_lock); 861 union_newsize(ap->a_vp, VNOVAL, vap->va_size); 862 } 863 864 if ((vap != ap->a_vap) && (vap->va_type == VDIR)) { 865 /* 866 * Link count manipulation: 867 * - If both return "2", return 2 (no subdirs) 868 * - If one or the other return "1", return "1" (ENOCLUE) 869 */ 870 if ((ap->a_vap->va_nlink == 2) && 871 (vap->va_nlink == 2)) 872 ; 873 else if (ap->a_vap->va_nlink != 1) { 874 if (vap->va_nlink == 1) 875 ap->a_vap->va_nlink = 1; 876 else 877 ap->a_vap->va_nlink += vap->va_nlink; 878 } 879 } 880 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0]; 881 return (0); 882 } 883 884 int 885 union_setattr(void *v) 886 { 887 struct vop_setattr_args /* { 888 struct vnode *a_vp; 889 struct vattr *a_vap; 890 kauth_cred_t a_cred; 891 } */ *ap = v; 892 struct vattr *vap = ap->a_vap; 893 struct vnode *vp = ap->a_vp; 894 struct union_node *un = VTOUNION(vp); 895 bool size_only; /* All but va_size are VNOVAL. */ 896 int error; 897 898 size_only = (vap->va_flags == VNOVAL && vap->va_uid == (uid_t)VNOVAL && 899 vap->va_gid == (gid_t)VNOVAL && vap->va_atime.tv_sec == VNOVAL && 900 vap->va_mtime.tv_sec == VNOVAL && vap->va_mode == (mode_t)VNOVAL); 901 902 if (!size_only && (vp->v_mount->mnt_flag & MNT_RDONLY)) 903 return (EROFS); 904 if (vap->va_size != VNOVAL) { 905 switch (vp->v_type) { 906 case VDIR: 907 return (EISDIR); 908 case VCHR: 909 case VBLK: 910 case VSOCK: 911 case VFIFO: 912 break; 913 case VREG: 914 case VLNK: 915 default: 916 /* 917 * Disallow write attempts if the filesystem is 918 * mounted read-only. 919 */ 920 if (vp->v_mount->mnt_flag & MNT_RDONLY) 921 return (EROFS); 922 } 923 } 924 925 /* 926 * Handle case of truncating lower object to zero size, 927 * by creating a zero length upper object. This is to 928 * handle the case of open with O_TRUNC and O_CREAT. 929 */ 930 if ((un->un_uppervp == NULLVP) && 931 /* assert(un->un_lowervp != NULLVP) */ 932 (un->un_lowervp->v_type == VREG)) { 933 error = union_copyup(un, (vap->va_size != 0), 934 ap->a_cred, curlwp); 935 if (error) 936 return (error); 937 } 938 939 /* 940 * Try to set attributes in upper layer, ignore size change to zero 941 * for devices to handle O_TRUNC and return read-only filesystem error 942 * otherwise. 943 */ 944 if (un->un_uppervp != NULLVP) { 945 error = VOP_SETATTR(un->un_uppervp, vap, ap->a_cred); 946 if ((error == 0) && (vap->va_size != VNOVAL)) { 947 mutex_enter(&un->un_lock); 948 union_newsize(ap->a_vp, vap->va_size, VNOVAL); 949 } 950 } else { 951 KASSERT(un->un_lowervp != NULLVP); 952 if (NODE_IS_SPECIAL(un->un_lowervp)) { 953 if (size_only && 954 (vap->va_size == 0 || vap->va_size == VNOVAL)) 955 error = 0; 956 else 957 error = EROFS; 958 } else { 959 error = EROFS; 960 } 961 } 962 963 return (error); 964 } 965 966 int 967 union_read(void *v) 968 { 969 struct vop_read_args /* { 970 struct vnode *a_vp; 971 struct uio *a_uio; 972 int a_ioflag; 973 kauth_cred_t a_cred; 974 } */ *ap = v; 975 int error; 976 struct vnode *vp = OTHERVP(ap->a_vp); 977 int dolock = (vp == LOWERVP(ap->a_vp)); 978 979 if (dolock) 980 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 981 error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 982 if (dolock) 983 VOP_UNLOCK(vp); 984 985 /* 986 * XXX 987 * perhaps the size of the underlying object has changed under 988 * our feet. take advantage of the offset information present 989 * in the uio structure. 990 */ 991 if (error == 0) { 992 struct union_node *un = VTOUNION(ap->a_vp); 993 off_t cur = ap->a_uio->uio_offset; 994 off_t usz = VNOVAL, lsz = VNOVAL; 995 996 mutex_enter(&un->un_lock); 997 if (vp == un->un_uppervp) { 998 if (cur > un->un_uppersz) 999 usz = cur; 1000 } else { 1001 if (cur > un->un_lowersz) 1002 lsz = cur; 1003 } 1004 1005 if (usz != VNOVAL || lsz != VNOVAL) 1006 union_newsize(ap->a_vp, usz, lsz); 1007 else 1008 mutex_exit(&un->un_lock); 1009 } 1010 1011 return (error); 1012 } 1013 1014 int 1015 union_write(void *v) 1016 { 1017 struct vop_read_args /* { 1018 struct vnode *a_vp; 1019 struct uio *a_uio; 1020 int a_ioflag; 1021 kauth_cred_t a_cred; 1022 } */ *ap = v; 1023 int error; 1024 struct vnode *vp; 1025 struct union_node *un = VTOUNION(ap->a_vp); 1026 1027 vp = UPPERVP(ap->a_vp); 1028 if (vp == NULLVP) { 1029 vp = LOWERVP(ap->a_vp); 1030 if (NODE_IS_SPECIAL(vp)) { 1031 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1032 error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, 1033 ap->a_cred); 1034 VOP_UNLOCK(vp); 1035 return error; 1036 } 1037 panic("union: missing upper layer in write"); 1038 } 1039 1040 error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); 1041 1042 /* 1043 * the size of the underlying object may be changed by the 1044 * write. 1045 */ 1046 if (error == 0) { 1047 off_t cur = ap->a_uio->uio_offset; 1048 1049 mutex_enter(&un->un_lock); 1050 if (cur > un->un_uppersz) 1051 union_newsize(ap->a_vp, cur, VNOVAL); 1052 else 1053 mutex_exit(&un->un_lock); 1054 } 1055 1056 return (error); 1057 } 1058 1059 int 1060 union_ioctl(void *v) 1061 { 1062 struct vop_ioctl_args /* { 1063 struct vnode *a_vp; 1064 int a_command; 1065 void *a_data; 1066 int a_fflag; 1067 kauth_cred_t a_cred; 1068 } */ *ap = v; 1069 struct vnode *ovp = OTHERVP(ap->a_vp); 1070 1071 ap->a_vp = ovp; 1072 return (VCALL(ovp, VOFFSET(vop_ioctl), ap)); 1073 } 1074 1075 int 1076 union_poll(void *v) 1077 { 1078 struct vop_poll_args /* { 1079 struct vnode *a_vp; 1080 int a_events; 1081 } */ *ap = v; 1082 struct vnode *ovp = OTHERVP(ap->a_vp); 1083 1084 ap->a_vp = ovp; 1085 return (VCALL(ovp, VOFFSET(vop_poll), ap)); 1086 } 1087 1088 int 1089 union_revoke(void *v) 1090 { 1091 struct vop_revoke_args /* { 1092 struct vnode *a_vp; 1093 int a_flags; 1094 struct proc *a_p; 1095 } */ *ap = v; 1096 struct vnode *vp = ap->a_vp; 1097 1098 if (UPPERVP(vp)) 1099 VOP_REVOKE(UPPERVP(vp), ap->a_flags); 1100 if (LOWERVP(vp)) 1101 VOP_REVOKE(LOWERVP(vp), ap->a_flags); 1102 vgone(vp); /* XXXAD?? */ 1103 return (0); 1104 } 1105 1106 int 1107 union_mmap(void *v) 1108 { 1109 struct vop_mmap_args /* { 1110 struct vnode *a_vp; 1111 vm_prot_t a_prot; 1112 kauth_cred_t a_cred; 1113 } */ *ap = v; 1114 struct vnode *ovp = OTHERVP(ap->a_vp); 1115 1116 ap->a_vp = ovp; 1117 return (VCALL(ovp, VOFFSET(vop_mmap), ap)); 1118 } 1119 1120 int 1121 union_fsync(void *v) 1122 { 1123 struct vop_fsync_args /* { 1124 struct vnode *a_vp; 1125 kauth_cred_t a_cred; 1126 int a_flags; 1127 off_t offhi; 1128 off_t offlo; 1129 } */ *ap = v; 1130 int error = 0; 1131 struct vnode *targetvp; 1132 1133 /* 1134 * If vinvalbuf is calling us, it's a "shallow fsync" -- don't 1135 * bother syncing the underlying vnodes, since (a) they'll be 1136 * fsync'ed when reclaimed and (b) we could deadlock if 1137 * they're locked; otherwise, pass it through to the 1138 * underlying layer. 1139 */ 1140 if (ap->a_vp->v_type == VBLK || ap->a_vp->v_type == VCHR) { 1141 error = spec_fsync(v); 1142 if (error) 1143 return error; 1144 } 1145 1146 if (ap->a_flags & FSYNC_RECLAIM) 1147 return 0; 1148 1149 targetvp = OTHERVP(ap->a_vp); 1150 if (targetvp != NULLVP) { 1151 int dolock = (targetvp == LOWERVP(ap->a_vp)); 1152 1153 if (dolock) 1154 vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY); 1155 error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags, 1156 ap->a_offlo, ap->a_offhi); 1157 if (dolock) 1158 VOP_UNLOCK(targetvp); 1159 } 1160 1161 return (error); 1162 } 1163 1164 int 1165 union_seek(void *v) 1166 { 1167 struct vop_seek_args /* { 1168 struct vnode *a_vp; 1169 off_t a_oldoff; 1170 off_t a_newoff; 1171 kauth_cred_t a_cred; 1172 } */ *ap = v; 1173 struct vnode *ovp = OTHERVP(ap->a_vp); 1174 1175 ap->a_vp = ovp; 1176 return (VCALL(ovp, VOFFSET(vop_seek), ap)); 1177 } 1178 1179 int 1180 union_remove(void *v) 1181 { 1182 struct vop_remove_v3_args /* { 1183 struct vnode *a_dvp; 1184 struct vnode *a_vp; 1185 struct componentname *a_cnp; 1186 nlink_t ctx_vp_new_nlink; 1187 } */ *ap = v; 1188 int error; 1189 struct union_node *dun = VTOUNION(ap->a_dvp); 1190 struct union_node *un = VTOUNION(ap->a_vp); 1191 struct componentname *cnp = ap->a_cnp; 1192 1193 if (dun->un_uppervp == NULLVP) 1194 panic("union remove: null upper vnode"); 1195 1196 if (un->un_uppervp != NULLVP) { 1197 struct vnode *dvp = dun->un_uppervp; 1198 struct vnode *vp = un->un_uppervp; 1199 1200 /* Account for VOP_REMOVE to vrele vp. */ 1201 vref(vp); 1202 if (union_dowhiteout(un, cnp->cn_cred)) 1203 cnp->cn_flags |= DOWHITEOUT; 1204 error = VOP_REMOVE(dvp, vp, cnp); 1205 if (!error) 1206 union_removed_upper(un); 1207 vrele(ap->a_vp); 1208 } else { 1209 error = union_mkwhiteout( 1210 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1211 dun->un_uppervp, ap->a_cnp, un); 1212 vput(ap->a_vp); 1213 } 1214 1215 return (error); 1216 } 1217 1218 int 1219 union_link(void *v) 1220 { 1221 struct vop_link_v2_args /* { 1222 struct vnode *a_dvp; 1223 struct vnode *a_vp; 1224 struct componentname *a_cnp; 1225 } */ *ap = v; 1226 int error = 0; 1227 struct componentname *cnp = ap->a_cnp; 1228 struct union_node *dun; 1229 struct vnode *vp; 1230 struct vnode *dvp; 1231 1232 dun = VTOUNION(ap->a_dvp); 1233 1234 KASSERT((ap->a_cnp->cn_flags & LOCKPARENT) != 0); 1235 1236 if (ap->a_dvp->v_op != ap->a_vp->v_op) { 1237 vp = ap->a_vp; 1238 } else { 1239 struct union_node *un = VTOUNION(ap->a_vp); 1240 if (un->un_uppervp == NULLVP) { 1241 const bool droplock = (dun->un_uppervp == un->un_dirvp); 1242 1243 /* 1244 * Needs to be copied before we can link it. 1245 */ 1246 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY); 1247 if (droplock) 1248 VOP_UNLOCK(dun->un_uppervp); 1249 error = union_copyup(un, 1, cnp->cn_cred, curlwp); 1250 if (droplock) { 1251 vn_lock(dun->un_uppervp, 1252 LK_EXCLUSIVE | LK_RETRY); 1253 /* 1254 * During copyup, we dropped the lock on the 1255 * dir and invalidated any saved namei lookup 1256 * state for the directory we'll be entering 1257 * the link in. We need to re-run the lookup 1258 * in that directory to reset any state needed 1259 * for VOP_LINK. 1260 * Call relookup on the union-layer to reset 1261 * the state. 1262 */ 1263 vp = NULLVP; 1264 if (dun->un_uppervp == NULLVP) 1265 panic("union: null upperdvp?"); 1266 error = relookup(ap->a_dvp, &vp, ap->a_cnp, 0); 1267 if (error) { 1268 VOP_UNLOCK(ap->a_vp); 1269 return EROFS; /* ? */ 1270 } 1271 if (vp != NULLVP) { 1272 /* 1273 * The name we want to create has 1274 * mysteriously appeared (a race?) 1275 */ 1276 error = EEXIST; 1277 VOP_UNLOCK(ap->a_vp); 1278 vput(vp); 1279 return (error); 1280 } 1281 } 1282 VOP_UNLOCK(ap->a_vp); 1283 } 1284 vp = un->un_uppervp; 1285 } 1286 1287 dvp = dun->un_uppervp; 1288 if (dvp == NULLVP) 1289 error = EROFS; 1290 1291 if (error) 1292 return (error); 1293 1294 return VOP_LINK(dvp, vp, cnp); 1295 } 1296 1297 int 1298 union_rename(void *v) 1299 { 1300 struct vop_rename_args /* { 1301 struct vnode *a_fdvp; 1302 struct vnode *a_fvp; 1303 struct componentname *a_fcnp; 1304 struct vnode *a_tdvp; 1305 struct vnode *a_tvp; 1306 struct componentname *a_tcnp; 1307 } */ *ap = v; 1308 int error; 1309 1310 struct vnode *fdvp = ap->a_fdvp; 1311 struct vnode *fvp = ap->a_fvp; 1312 struct vnode *tdvp = ap->a_tdvp; 1313 struct vnode *tvp = ap->a_tvp; 1314 1315 /* 1316 * Account for VOP_RENAME to vrele all nodes. 1317 * Note: VOP_RENAME will unlock tdvp. 1318 */ 1319 1320 if (fdvp->v_op == union_vnodeop_p) { /* always true */ 1321 struct union_node *un = VTOUNION(fdvp); 1322 if (un->un_uppervp == NULLVP) { 1323 /* 1324 * this should never happen in normal 1325 * operation but might if there was 1326 * a problem creating the top-level shadow 1327 * directory. 1328 */ 1329 error = EXDEV; 1330 goto bad; 1331 } 1332 1333 fdvp = un->un_uppervp; 1334 vref(fdvp); 1335 } 1336 1337 if (fvp->v_op == union_vnodeop_p) { /* always true */ 1338 struct union_node *un = VTOUNION(fvp); 1339 if (un->un_uppervp == NULLVP) { 1340 /* XXX: should do a copyup */ 1341 error = EXDEV; 1342 goto bad; 1343 } 1344 1345 if (un->un_lowervp != NULLVP) 1346 ap->a_fcnp->cn_flags |= DOWHITEOUT; 1347 1348 fvp = un->un_uppervp; 1349 vref(fvp); 1350 } 1351 1352 if (tdvp->v_op == union_vnodeop_p) { 1353 struct union_node *un = VTOUNION(tdvp); 1354 if (un->un_uppervp == NULLVP) { 1355 /* 1356 * this should never happen in normal 1357 * operation but might if there was 1358 * a problem creating the top-level shadow 1359 * directory. 1360 */ 1361 error = EXDEV; 1362 goto bad; 1363 } 1364 1365 tdvp = un->un_uppervp; 1366 vref(tdvp); 1367 } 1368 1369 if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) { 1370 struct union_node *un = VTOUNION(tvp); 1371 1372 tvp = un->un_uppervp; 1373 if (tvp != NULLVP) { 1374 vref(tvp); 1375 } 1376 } 1377 1378 error = VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp); 1379 goto out; 1380 1381 bad: 1382 vput(tdvp); 1383 if (tvp != NULLVP) 1384 vput(tvp); 1385 vrele(fdvp); 1386 vrele(fvp); 1387 1388 out: 1389 if (fdvp != ap->a_fdvp) { 1390 vrele(ap->a_fdvp); 1391 } 1392 if (fvp != ap->a_fvp) { 1393 vrele(ap->a_fvp); 1394 } 1395 if (tdvp != ap->a_tdvp) { 1396 vrele(ap->a_tdvp); 1397 } 1398 if (tvp != ap->a_tvp) { 1399 vrele(ap->a_tvp); 1400 } 1401 return (error); 1402 } 1403 1404 int 1405 union_mkdir(void *v) 1406 { 1407 struct vop_mkdir_v3_args /* { 1408 struct vnode *a_dvp; 1409 struct vnode **a_vpp; 1410 struct componentname *a_cnp; 1411 struct vattr *a_vap; 1412 } */ *ap = v; 1413 struct union_node *un = VTOUNION(ap->a_dvp); 1414 struct vnode *dvp = un->un_uppervp; 1415 struct componentname *cnp = ap->a_cnp; 1416 1417 if (dvp != NULLVP) { 1418 int error; 1419 struct vnode *vp; 1420 1421 vp = NULL; 1422 error = VOP_MKDIR(dvp, &vp, cnp, ap->a_vap); 1423 if (error) { 1424 vrele(ap->a_dvp); 1425 return (error); 1426 } 1427 1428 error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, 1429 NULLVP, cnp, vp, NULLVP, 1); 1430 if (error) 1431 vrele(vp); 1432 return (error); 1433 } 1434 1435 return (EROFS); 1436 } 1437 1438 int 1439 union_rmdir(void *v) 1440 { 1441 struct vop_rmdir_v2_args /* { 1442 struct vnode *a_dvp; 1443 struct vnode *a_vp; 1444 struct componentname *a_cnp; 1445 } */ *ap = v; 1446 int error; 1447 struct union_node *dun = VTOUNION(ap->a_dvp); 1448 struct union_node *un = VTOUNION(ap->a_vp); 1449 struct componentname *cnp = ap->a_cnp; 1450 1451 if (dun->un_uppervp == NULLVP) 1452 panic("union rmdir: null upper vnode"); 1453 1454 error = union_check_rmdir(un, cnp->cn_cred); 1455 if (error) { 1456 vput(ap->a_vp); 1457 return error; 1458 } 1459 1460 if (un->un_uppervp != NULLVP) { 1461 struct vnode *dvp = dun->un_uppervp; 1462 struct vnode *vp = un->un_uppervp; 1463 1464 /* Account for VOP_RMDIR to vrele vp. */ 1465 vref(vp); 1466 if (union_dowhiteout(un, cnp->cn_cred)) 1467 cnp->cn_flags |= DOWHITEOUT; 1468 error = VOP_RMDIR(dvp, vp, ap->a_cnp); 1469 if (!error) 1470 union_removed_upper(un); 1471 vrele(ap->a_vp); 1472 } else { 1473 error = union_mkwhiteout( 1474 MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), 1475 dun->un_uppervp, ap->a_cnp, un); 1476 vput(ap->a_vp); 1477 } 1478 1479 return (error); 1480 } 1481 1482 int 1483 union_symlink(void *v) 1484 { 1485 struct vop_symlink_v3_args /* { 1486 struct vnode *a_dvp; 1487 struct vnode **a_vpp; 1488 struct componentname *a_cnp; 1489 struct vattr *a_vap; 1490 char *a_target; 1491 } */ *ap = v; 1492 struct union_node *un = VTOUNION(ap->a_dvp); 1493 struct vnode *dvp = un->un_uppervp; 1494 struct componentname *cnp = ap->a_cnp; 1495 1496 if (dvp != NULLVP) { 1497 int error; 1498 1499 error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap, 1500 ap->a_target); 1501 return (error); 1502 } 1503 1504 return (EROFS); 1505 } 1506 1507 /* 1508 * union_readdir works in concert with getdirentries and 1509 * readdir(3) to provide a list of entries in the unioned 1510 * directories. getdirentries is responsible for walking 1511 * down the union stack. readdir(3) is responsible for 1512 * eliminating duplicate names from the returned data stream. 1513 */ 1514 int 1515 union_readdir(void *v) 1516 { 1517 struct vop_readdir_args /* { 1518 struct vnodeop_desc *a_desc; 1519 struct vnode *a_vp; 1520 struct uio *a_uio; 1521 kauth_cred_t a_cred; 1522 int *a_eofflag; 1523 u_long *a_cookies; 1524 int a_ncookies; 1525 } */ *ap = v; 1526 struct union_node *un = VTOUNION(ap->a_vp); 1527 struct vnode *vp; 1528 int dolock, error; 1529 1530 if (un->un_hooknode) { 1531 KASSERT(un->un_uppervp == NULLVP); 1532 KASSERT(un->un_lowervp != NULLVP); 1533 vp = un->un_lowervp; 1534 dolock = 1; 1535 } else { 1536 vp = un->un_uppervp; 1537 dolock = 0; 1538 } 1539 if (vp == NULLVP) 1540 return 0; 1541 1542 if (dolock) 1543 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1544 ap->a_vp = vp; 1545 error = VCALL(vp, VOFFSET(vop_readdir), ap); 1546 if (dolock) 1547 VOP_UNLOCK(vp); 1548 1549 return error; 1550 } 1551 1552 int 1553 union_readlink(void *v) 1554 { 1555 struct vop_readlink_args /* { 1556 struct vnode *a_vp; 1557 struct uio *a_uio; 1558 kauth_cred_t a_cred; 1559 } */ *ap = v; 1560 int error; 1561 struct vnode *vp = OTHERVP(ap->a_vp); 1562 int dolock = (vp == LOWERVP(ap->a_vp)); 1563 1564 if (dolock) 1565 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1566 ap->a_vp = vp; 1567 error = VCALL(vp, VOFFSET(vop_readlink), ap); 1568 if (dolock) 1569 VOP_UNLOCK(vp); 1570 1571 return (error); 1572 } 1573 1574 int 1575 union_abortop(void *v) 1576 { 1577 struct vop_abortop_args /* { 1578 struct vnode *a_dvp; 1579 struct componentname *a_cnp; 1580 } */ *ap = v; 1581 1582 KASSERT(UPPERVP(ap->a_dvp) != NULL); 1583 1584 ap->a_dvp = UPPERVP(ap->a_dvp); 1585 return VCALL(ap->a_dvp, VOFFSET(vop_abortop), ap); 1586 } 1587 1588 int 1589 union_inactive(void *v) 1590 { 1591 struct vop_inactive_v2_args /* { 1592 const struct vnodeop_desc *a_desc; 1593 struct vnode *a_vp; 1594 bool *a_recycle; 1595 } */ *ap = v; 1596 struct vnode *vp = ap->a_vp; 1597 struct union_node *un = VTOUNION(vp); 1598 struct vnode **vpp; 1599 1600 /* 1601 * Do nothing (and _don't_ bypass). 1602 * Wait to vrele lowervp until reclaim, 1603 * so that until then our union_node is in the 1604 * cache and reusable. 1605 * 1606 * NEEDSWORK: Someday, consider inactive'ing 1607 * the lowervp and then trying to reactivate it 1608 * with capabilities (v_id) 1609 * like they do in the name lookup cache code. 1610 * That's too much work for now. 1611 */ 1612 1613 if (un->un_dircache != 0) { 1614 for (vpp = un->un_dircache; *vpp != NULLVP; vpp++) 1615 vrele(*vpp); 1616 free(un->un_dircache, M_TEMP); 1617 un->un_dircache = 0; 1618 } 1619 1620 *ap->a_recycle = ((un->un_cflags & UN_CACHED) == 0); 1621 1622 return (0); 1623 } 1624 1625 int 1626 union_reclaim(void *v) 1627 { 1628 struct vop_reclaim_v2_args /* { 1629 struct vnode *a_vp; 1630 } */ *ap = v; 1631 struct vnode *vp = ap->a_vp; 1632 struct vnode *uvp = UPPERVP(vp); 1633 1634 VOP_UNLOCK(vp); 1635 1636 if (uvp != NULL) { 1637 mutex_enter(uvp->v_interlock); 1638 KASSERT(vp->v_interlock == uvp->v_interlock); 1639 uvp->v_writecount -= vp->v_writecount; 1640 mutex_exit(uvp->v_interlock); 1641 } 1642 1643 union_freevp(vp); 1644 1645 return (0); 1646 } 1647 1648 static int 1649 union_lock1(struct vnode *vp, struct vnode *lockvp, int flags) 1650 { 1651 struct vop_lock_args ap; 1652 1653 ap.a_desc = VDESC(vop_lock); 1654 ap.a_vp = lockvp; 1655 ap.a_flags = flags; 1656 1657 if (lockvp == vp) 1658 return genfs_lock(&ap); 1659 else 1660 return VCALL(ap.a_vp, VOFFSET(vop_lock), &ap); 1661 } 1662 1663 static int 1664 union_unlock1(struct vnode *vp, struct vnode *lockvp) 1665 { 1666 struct vop_unlock_args ap; 1667 1668 ap.a_desc = VDESC(vop_unlock); 1669 ap.a_vp = lockvp; 1670 1671 if (lockvp == vp) 1672 return genfs_unlock(&ap); 1673 else 1674 return VCALL(ap.a_vp, VOFFSET(vop_unlock), &ap); 1675 } 1676 1677 int 1678 union_lock(void *v) 1679 { 1680 struct vop_lock_args /* { 1681 struct vnode *a_vp; 1682 int a_flags; 1683 } */ *ap = v; 1684 struct vnode *vp = ap->a_vp, *lockvp; 1685 struct union_node *un = VTOUNION(vp); 1686 int flags = ap->a_flags; 1687 int error; 1688 1689 if ((flags & LK_NOWAIT) != 0) { 1690 if (!mutex_tryenter(&un->un_lock)) 1691 return EBUSY; 1692 lockvp = LOCKVP(vp); 1693 error = union_lock1(vp, lockvp, flags); 1694 mutex_exit(&un->un_lock); 1695 if (error) 1696 return error; 1697 if (mutex_tryenter(vp->v_interlock)) { 1698 error = vdead_check(vp, VDEAD_NOWAIT); 1699 mutex_exit(vp->v_interlock); 1700 } else 1701 error = EBUSY; 1702 if (error) 1703 union_unlock1(vp, lockvp); 1704 return error; 1705 } 1706 1707 mutex_enter(&un->un_lock); 1708 for (;;) { 1709 lockvp = LOCKVP(vp); 1710 mutex_exit(&un->un_lock); 1711 error = union_lock1(vp, lockvp, flags); 1712 if (error != 0) 1713 return error; 1714 mutex_enter(&un->un_lock); 1715 if (lockvp == LOCKVP(vp)) 1716 break; 1717 union_unlock1(vp, lockvp); 1718 } 1719 mutex_exit(&un->un_lock); 1720 1721 mutex_enter(vp->v_interlock); 1722 error = vdead_check(vp, VDEAD_NOWAIT); 1723 if (error) { 1724 union_unlock1(vp, lockvp); 1725 error = vdead_check(vp, 0); 1726 KASSERT(error == ENOENT); 1727 } 1728 mutex_exit(vp->v_interlock); 1729 return error; 1730 } 1731 1732 int 1733 union_unlock(void *v) 1734 { 1735 struct vop_unlock_args /* { 1736 struct vnode *a_vp; 1737 int a_flags; 1738 } */ *ap = v; 1739 struct vnode *vp = ap->a_vp, *lockvp; 1740 1741 lockvp = LOCKVP(vp); 1742 union_unlock1(vp, lockvp); 1743 1744 return 0; 1745 } 1746 1747 int 1748 union_bmap(void *v) 1749 { 1750 struct vop_bmap_args /* { 1751 struct vnode *a_vp; 1752 daddr_t a_bn; 1753 struct vnode **a_vpp; 1754 daddr_t *a_bnp; 1755 int *a_runp; 1756 } */ *ap = v; 1757 int error; 1758 struct vnode *vp = OTHERVP(ap->a_vp); 1759 int dolock = (vp == LOWERVP(ap->a_vp)); 1760 1761 if (dolock) 1762 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1763 ap->a_vp = vp; 1764 error = VCALL(vp, VOFFSET(vop_bmap), ap); 1765 if (dolock) 1766 VOP_UNLOCK(vp); 1767 1768 return (error); 1769 } 1770 1771 int 1772 union_print(void *v) 1773 { 1774 struct vop_print_args /* { 1775 struct vnode *a_vp; 1776 } */ *ap = v; 1777 struct vnode *vp = ap->a_vp; 1778 1779 printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n", 1780 vp, UPPERVP(vp), LOWERVP(vp)); 1781 if (UPPERVP(vp) != NULLVP) 1782 vprint("union: upper", UPPERVP(vp)); 1783 if (LOWERVP(vp) != NULLVP) 1784 vprint("union: lower", LOWERVP(vp)); 1785 if (VTOUNION(vp)->un_dircache) { 1786 struct vnode **vpp; 1787 for (vpp = VTOUNION(vp)->un_dircache; *vpp != NULLVP; vpp++) 1788 vprint("dircache:", *vpp); 1789 } 1790 1791 return (0); 1792 } 1793 1794 int 1795 union_islocked(void *v) 1796 { 1797 struct vop_islocked_args /* { 1798 struct vnode *a_vp; 1799 } */ *ap = v; 1800 struct vnode *vp; 1801 struct union_node *un; 1802 1803 un = VTOUNION(ap->a_vp); 1804 mutex_enter(&un->un_lock); 1805 vp = LOCKVP(ap->a_vp); 1806 mutex_exit(&un->un_lock); 1807 1808 if (vp == ap->a_vp) 1809 return genfs_islocked(ap); 1810 else 1811 return VOP_ISLOCKED(vp); 1812 } 1813 1814 int 1815 union_pathconf(void *v) 1816 { 1817 struct vop_pathconf_args /* { 1818 struct vnode *a_vp; 1819 int a_name; 1820 int *a_retval; 1821 } */ *ap = v; 1822 int error; 1823 struct vnode *vp = OTHERVP(ap->a_vp); 1824 int dolock = (vp == LOWERVP(ap->a_vp)); 1825 1826 if (dolock) 1827 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1828 ap->a_vp = vp; 1829 error = VCALL(vp, VOFFSET(vop_pathconf), ap); 1830 if (dolock) 1831 VOP_UNLOCK(vp); 1832 1833 return (error); 1834 } 1835 1836 int 1837 union_advlock(void *v) 1838 { 1839 struct vop_advlock_args /* { 1840 struct vnode *a_vp; 1841 void *a_id; 1842 int a_op; 1843 struct flock *a_fl; 1844 int a_flags; 1845 } */ *ap = v; 1846 struct vnode *ovp = OTHERVP(ap->a_vp); 1847 1848 ap->a_vp = ovp; 1849 return (VCALL(ovp, VOFFSET(vop_advlock), ap)); 1850 } 1851 1852 int 1853 union_strategy(void *v) 1854 { 1855 struct vop_strategy_args /* { 1856 struct vnode *a_vp; 1857 struct buf *a_bp; 1858 } */ *ap = v; 1859 struct vnode *ovp = OTHERVP(ap->a_vp); 1860 struct buf *bp = ap->a_bp; 1861 1862 KASSERT(ovp != NULLVP); 1863 if (!NODE_IS_SPECIAL(ovp)) 1864 KASSERT((bp->b_flags & B_READ) || ovp != LOWERVP(bp->b_vp)); 1865 1866 return (VOP_STRATEGY(ovp, bp)); 1867 } 1868 1869 int 1870 union_bwrite(void *v) 1871 { 1872 struct vop_bwrite_args /* { 1873 struct vnode *a_vp; 1874 struct buf *a_bp; 1875 } */ *ap = v; 1876 struct vnode *ovp = OTHERVP(ap->a_vp); 1877 struct buf *bp = ap->a_bp; 1878 1879 KASSERT(ovp != NULLVP); 1880 if (!NODE_IS_SPECIAL(ovp)) 1881 KASSERT((bp->b_flags & B_READ) || ovp != LOWERVP(bp->b_vp)); 1882 1883 return (VOP_BWRITE(ovp, bp)); 1884 } 1885 1886 int 1887 union_getpages(void *v) 1888 { 1889 struct vop_getpages_args /* { 1890 struct vnode *a_vp; 1891 voff_t a_offset; 1892 struct vm_page **a_m; 1893 int *a_count; 1894 int a_centeridx; 1895 vm_prot_t a_access_type; 1896 int a_advice; 1897 int a_flags; 1898 } */ *ap = v; 1899 struct vnode *vp = ap->a_vp; 1900 1901 KASSERT(rw_lock_held(vp->v_uobj.vmobjlock)); 1902 1903 if (ap->a_flags & PGO_LOCKED) { 1904 return EBUSY; 1905 } 1906 ap->a_vp = OTHERVP(vp); 1907 KASSERT(vp->v_uobj.vmobjlock == ap->a_vp->v_uobj.vmobjlock); 1908 1909 /* Just pass the request on to the underlying layer. */ 1910 return VCALL(ap->a_vp, VOFFSET(vop_getpages), ap); 1911 } 1912 1913 int 1914 union_putpages(void *v) 1915 { 1916 struct vop_putpages_args /* { 1917 struct vnode *a_vp; 1918 voff_t a_offlo; 1919 voff_t a_offhi; 1920 int a_flags; 1921 } */ *ap = v; 1922 struct vnode *vp = ap->a_vp; 1923 1924 KASSERT(rw_lock_held(vp->v_uobj.vmobjlock)); 1925 1926 ap->a_vp = OTHERVP(vp); 1927 KASSERT(vp->v_uobj.vmobjlock == ap->a_vp->v_uobj.vmobjlock); 1928 1929 if (ap->a_flags & PGO_RECLAIM) { 1930 rw_exit(vp->v_uobj.vmobjlock); 1931 return 0; 1932 } 1933 1934 /* Just pass the request on to the underlying layer. */ 1935 return VCALL(ap->a_vp, VOFFSET(vop_putpages), ap); 1936 } 1937 1938 int 1939 union_kqfilter(void *v) 1940 { 1941 struct vop_kqfilter_args /* { 1942 struct vnode *a_vp; 1943 struct knote *a_kn; 1944 } */ *ap = v; 1945 int error; 1946 1947 /* 1948 * We watch either the upper layer file (if it already exists), 1949 * or the lower layer one. If there is lower layer file only 1950 * at this moment, we will keep watching that lower layer file 1951 * even if upper layer file would be created later on. 1952 */ 1953 if (UPPERVP(ap->a_vp)) 1954 error = VOP_KQFILTER(UPPERVP(ap->a_vp), ap->a_kn); 1955 else if (LOWERVP(ap->a_vp)) 1956 error = VOP_KQFILTER(LOWERVP(ap->a_vp), ap->a_kn); 1957 else { 1958 /* panic? */ 1959 error = EOPNOTSUPP; 1960 } 1961 1962 return (error); 1963 } 1964
Indexes created Mon Sep 29 21:09:56 GMT 2025