1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1994 Jan-Simon Pendry 5 * Copyright (c) 1994 6 * The Regents of the University of California. All rights reserved. 7 * Copyright (c) 2005, 2006, 2012 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc. 8 * Copyright (c) 2006, 2012 Daichi Goto <daichi@freebsd.org> 9 * 10 * This code is derived from software contributed to Berkeley by 11 * Jan-Simon Pendry. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)union_subr.c 8.20 (Berkeley) 5/20/95 38 * $FreeBSD$ 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kernel.h> 44 #include <sys/ktr.h> 45 #include <sys/lock.h> 46 #include <sys/mutex.h> 47 #include <sys/malloc.h> 48 #include <sys/mount.h> 49 #include <sys/namei.h> 50 #include <sys/proc.h> 51 #include <sys/vnode.h> 52 #include <sys/dirent.h> 53 #include <sys/fcntl.h> 54 #include <sys/filedesc.h> 55 #include <sys/stat.h> 56 #include <sys/sysctl.h> 57 #include <sys/taskqueue.h> 58 #include <sys/resourcevar.h> 59 60 #include <machine/atomic.h> 61 62 #include <security/mac/mac_framework.h> 63 64 #include <vm/uma.h> 65 66 #include <fs/unionfs/union.h> 67 68 #define NUNIONFSNODECACHE 16 69 #define UNIONFSHASHMASK (NUNIONFSNODECACHE - 1) 70 71 static MALLOC_DEFINE(M_UNIONFSHASH, "UNIONFS hash", "UNIONFS hash table"); 72 MALLOC_DEFINE(M_UNIONFSNODE, "UNIONFS node", "UNIONFS vnode private part"); 73 MALLOC_DEFINE(M_UNIONFSPATH, "UNIONFS path", "UNIONFS path private part"); 74 75 static struct task unionfs_deferred_rele_task; 76 static struct mtx unionfs_deferred_rele_lock; 77 static STAILQ_HEAD(, unionfs_node) unionfs_deferred_rele_list = 78 STAILQ_HEAD_INITIALIZER(unionfs_deferred_rele_list); 79 static TASKQUEUE_DEFINE_THREAD(unionfs_rele); 80 81 unsigned int unionfs_ndeferred = 0; 82 SYSCTL_UINT(_vfs, OID_AUTO, unionfs_ndeferred, CTLFLAG_RD, 83 &unionfs_ndeferred, 0, "unionfs deferred vnode release"); 84 85 static void unionfs_deferred_rele(void *, int); 86 87 /* 88 * Initialize 89 */ 90 int 91 unionfs_init(struct vfsconf *vfsp) 92 { 93 UNIONFSDEBUG("unionfs_init\n"); /* printed during system boot */ 94 TASK_INIT(&unionfs_deferred_rele_task, 0, unionfs_deferred_rele, NULL); 95 mtx_init(&unionfs_deferred_rele_lock, "uniondefr", NULL, MTX_DEF); 96 return (0); 97 } 98 99 /* 100 * Uninitialize 101 */ 102 int 103 unionfs_uninit(struct vfsconf *vfsp) 104 { 105 taskqueue_quiesce(taskqueue_unionfs_rele); 106 taskqueue_free(taskqueue_unionfs_rele); 107 mtx_destroy(&unionfs_deferred_rele_lock); 108 return (0); 109 } 110 111 static void 112 unionfs_deferred_rele(void *arg __unused, int pending __unused) 113 { 114 STAILQ_HEAD(, unionfs_node) local_rele_list; 115 struct unionfs_node *unp, *tunp; 116 unsigned int ndeferred; 117 118 ndeferred = 0; 119 STAILQ_INIT(&local_rele_list); 120 mtx_lock(&unionfs_deferred_rele_lock); 121 STAILQ_CONCAT(&local_rele_list, &unionfs_deferred_rele_list); 122 mtx_unlock(&unionfs_deferred_rele_lock); 123 STAILQ_FOREACH_SAFE(unp, &local_rele_list, un_rele, tunp) { 124 ++ndeferred; 125 MPASS(unp->un_dvp != NULL); 126 vrele(unp->un_dvp); 127 free(unp, M_UNIONFSNODE); 128 } 129 130 /* We expect this function to be single-threaded, thus no atomic */ 131 unionfs_ndeferred += ndeferred; 132 } 133 134 static struct unionfs_node_hashhead * 135 unionfs_get_hashhead(struct vnode *dvp, struct vnode *lookup) 136 { 137 struct unionfs_node *unp; 138 139 unp = VTOUNIONFS(dvp); 140 141 return (&(unp->un_hashtbl[vfs_hash_index(lookup) & UNIONFSHASHMASK])); 142 } 143 144 /* 145 * Attempt to lookup a cached unionfs vnode by upper/lower vp 146 * from dvp, with dvp's interlock held. 147 */ 148 static struct vnode * 149 unionfs_get_cached_vnode_locked(struct vnode *lookup, struct vnode *dvp) 150 { 151 struct unionfs_node *unp; 152 struct unionfs_node_hashhead *hd; 153 struct vnode *vp; 154 155 hd = unionfs_get_hashhead(dvp, lookup); 156 157 LIST_FOREACH(unp, hd, un_hash) { 158 if (unp->un_uppervp == lookup || 159 unp->un_lowervp == lookup) { 160 vp = UNIONFSTOV(unp); 161 VI_LOCK_FLAGS(vp, MTX_DUPOK); 162 vp->v_iflag &= ~VI_OWEINACT; 163 if (VN_IS_DOOMED(vp) || 164 ((vp->v_iflag & VI_DOINGINACT) != 0)) { 165 VI_UNLOCK(vp); 166 vp = NULLVP; 167 } else { 168 vrefl(vp); 169 VI_UNLOCK(vp); 170 } 171 return (vp); 172 } 173 } 174 175 return (NULLVP); 176 } 177 178 179 /* 180 * Get the cached vnode. 181 */ 182 static struct vnode * 183 unionfs_get_cached_vnode(struct vnode *uvp, struct vnode *lvp, 184 struct vnode *dvp) 185 { 186 struct vnode *vp; 187 188 vp = NULLVP; 189 VI_LOCK(dvp); 190 if (uvp != NULLVP) 191 vp = unionfs_get_cached_vnode_locked(uvp, dvp); 192 else if (lvp != NULLVP) 193 vp = unionfs_get_cached_vnode_locked(lvp, dvp); 194 VI_UNLOCK(dvp); 195 196 return (vp); 197 } 198 199 /* 200 * Add the new vnode into cache. 201 */ 202 static struct vnode * 203 unionfs_ins_cached_vnode(struct unionfs_node *uncp, 204 struct vnode *dvp) 205 { 206 struct unionfs_node_hashhead *hd; 207 struct vnode *vp; 208 209 ASSERT_VOP_ELOCKED(uncp->un_uppervp, __func__); 210 ASSERT_VOP_ELOCKED(uncp->un_lowervp, __func__); 211 KASSERT(uncp->un_uppervp == NULLVP || uncp->un_uppervp->v_type == VDIR, 212 ("%s: v_type != VDIR", __func__)); 213 KASSERT(uncp->un_lowervp == NULLVP || uncp->un_lowervp->v_type == VDIR, 214 ("%s: v_type != VDIR", __func__)); 215 216 vp = NULLVP; 217 VI_LOCK(dvp); 218 if (uncp->un_uppervp != NULL) 219 vp = unionfs_get_cached_vnode_locked(uncp->un_uppervp, dvp); 220 else if (uncp->un_lowervp != NULL) 221 vp = unionfs_get_cached_vnode_locked(uncp->un_lowervp, dvp); 222 if (vp == NULLVP) { 223 hd = unionfs_get_hashhead(dvp, (uncp->un_uppervp != NULLVP ? 224 uncp->un_uppervp : uncp->un_lowervp)); 225 LIST_INSERT_HEAD(hd, uncp, un_hash); 226 } 227 VI_UNLOCK(dvp); 228 229 return (vp); 230 } 231 232 /* 233 * Remove the vnode. 234 */ 235 static void 236 unionfs_rem_cached_vnode(struct unionfs_node *unp, struct vnode *dvp) 237 { 238 KASSERT(unp != NULL, ("%s: null node", __func__)); 239 KASSERT(dvp != NULLVP, 240 ("%s: null parent vnode", __func__)); 241 242 VI_LOCK(dvp); 243 if (unp->un_hash.le_prev != NULL) { 244 LIST_REMOVE(unp, un_hash); 245 unp->un_hash.le_next = NULL; 246 unp->un_hash.le_prev = NULL; 247 } 248 VI_UNLOCK(dvp); 249 } 250 251 /* 252 * Common cleanup handling for unionfs_nodeget 253 * Upper, lower, and parent directory vnodes are expected to be referenced by 254 * the caller. Upper and lower vnodes, if non-NULL, are also expected to be 255 * exclusively locked by the caller. 256 * This function will return with the caller's locks and references undone. 257 */ 258 static void 259 unionfs_nodeget_cleanup(struct vnode *vp, struct unionfs_node *unp) 260 { 261 262 /* 263 * Lock and reset the default vnode lock; vgone() expects a locked 264 * vnode, and we're going to reset the vnode ops. 265 */ 266 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 267 268 /* 269 * Clear out private data and reset the vnode ops to avoid use of 270 * unionfs vnode ops on a partially constructed vnode. 271 */ 272 VI_LOCK(vp); 273 vp->v_data = NULL; 274 vp->v_vnlock = &vp->v_lock; 275 vp->v_op = &dead_vnodeops; 276 VI_UNLOCK(vp); 277 vgone(vp); 278 vput(vp); 279 280 if (unp->un_dvp != NULLVP) 281 vrele(unp->un_dvp); 282 if (unp->un_uppervp != NULLVP) 283 vput(unp->un_uppervp); 284 if (unp->un_lowervp != NULLVP) 285 vput(unp->un_lowervp); 286 if (unp->un_hashtbl != NULL) 287 hashdestroy(unp->un_hashtbl, M_UNIONFSHASH, UNIONFSHASHMASK); 288 free(unp->un_path, M_UNIONFSPATH); 289 free(unp, M_UNIONFSNODE); 290 } 291 292 /* 293 * Make a new or get existing unionfs node. 294 * 295 * uppervp and lowervp should be unlocked. Because if new unionfs vnode is 296 * locked, uppervp or lowervp is locked too. In order to prevent dead lock, 297 * you should not lock plurality simultaneously. 298 */ 299 int 300 unionfs_nodeget(struct mount *mp, struct vnode *uppervp, 301 struct vnode *lowervp, struct vnode *dvp, struct vnode **vpp, 302 struct componentname *cnp) 303 { 304 char *path; 305 struct unionfs_mount *ump; 306 struct unionfs_node *unp; 307 struct vnode *vp; 308 u_long hashmask; 309 int error; 310 int lkflags; 311 enum vtype vt; 312 313 error = 0; 314 ump = MOUNTTOUNIONFSMOUNT(mp); 315 lkflags = (cnp ? cnp->cn_lkflags : 0); 316 path = (cnp ? cnp->cn_nameptr : NULL); 317 *vpp = NULLVP; 318 319 if (uppervp == NULLVP && lowervp == NULLVP) 320 panic("%s: upper and lower is null", __func__); 321 322 vt = (uppervp != NULLVP ? uppervp->v_type : lowervp->v_type); 323 324 /* If it has no ISLASTCN flag, path check is skipped. */ 325 if (cnp && !(cnp->cn_flags & ISLASTCN)) 326 path = NULL; 327 328 /* check the cache */ 329 if (dvp != NULLVP && vt == VDIR) { 330 vp = unionfs_get_cached_vnode(uppervp, lowervp, dvp); 331 if (vp != NULLVP) { 332 *vpp = vp; 333 goto unionfs_nodeget_out; 334 } 335 } 336 337 unp = malloc(sizeof(struct unionfs_node), 338 M_UNIONFSNODE, M_WAITOK | M_ZERO); 339 340 error = getnewvnode("unionfs", mp, &unionfs_vnodeops, &vp); 341 if (error != 0) { 342 free(unp, M_UNIONFSNODE); 343 return (error); 344 } 345 if (dvp != NULLVP) 346 vref(dvp); 347 if (uppervp != NULLVP) 348 vref(uppervp); 349 if (lowervp != NULLVP) 350 vref(lowervp); 351 352 if (vt == VDIR) { 353 unp->un_hashtbl = hashinit(NUNIONFSNODECACHE, M_UNIONFSHASH, 354 &hashmask); 355 KASSERT(hashmask == UNIONFSHASHMASK, 356 ("unexpected unionfs hash mask 0x%lx", hashmask)); 357 } 358 359 unp->un_vnode = vp; 360 unp->un_uppervp = uppervp; 361 unp->un_lowervp = lowervp; 362 unp->un_dvp = dvp; 363 if (uppervp != NULLVP) 364 vp->v_vnlock = uppervp->v_vnlock; 365 else 366 vp->v_vnlock = lowervp->v_vnlock; 367 368 if (path != NULL) { 369 unp->un_path = malloc(cnp->cn_namelen + 1, 370 M_UNIONFSPATH, M_WAITOK | M_ZERO); 371 bcopy(cnp->cn_nameptr, unp->un_path, cnp->cn_namelen); 372 unp->un_path[cnp->cn_namelen] = '\0'; 373 unp->un_pathlen = cnp->cn_namelen; 374 } 375 vp->v_type = vt; 376 vp->v_data = unp; 377 378 /* 379 * TODO: This is an imperfect check, as there's no guarantee that 380 * the underlying filesystems will always return vnode pointers 381 * for the root inodes that match our cached values. To reduce 382 * the likelihood of failure, for example in the case where either 383 * vnode has been forcibly doomed, we check both pointers and set 384 * VV_ROOT if either matches. 385 */ 386 if (ump->um_uppervp == uppervp || ump->um_lowervp == lowervp) 387 vp->v_vflag |= VV_ROOT; 388 KASSERT(dvp != NULL || (vp->v_vflag & VV_ROOT) != 0, 389 ("%s: NULL dvp for non-root vp %p", __func__, vp)); 390 391 vn_lock_pair(lowervp, false, uppervp, false); 392 error = insmntque1(vp, mp); 393 if (error != 0) { 394 unionfs_nodeget_cleanup(vp, unp); 395 return (error); 396 } 397 if (lowervp != NULL && VN_IS_DOOMED(lowervp)) { 398 vput(lowervp); 399 unp->un_lowervp = NULL; 400 } 401 if (uppervp != NULL && VN_IS_DOOMED(uppervp)) { 402 vput(uppervp); 403 unp->un_uppervp = NULL; 404 } 405 if (unp->un_lowervp == NULL && unp->un_uppervp == NULL) { 406 unionfs_nodeget_cleanup(vp, unp); 407 return (ENOENT); 408 } 409 410 vn_set_state(vp, VSTATE_CONSTRUCTED); 411 412 if (dvp != NULLVP && vt == VDIR) 413 *vpp = unionfs_ins_cached_vnode(unp, dvp); 414 if (*vpp != NULLVP) { 415 unionfs_nodeget_cleanup(vp, unp); 416 vp = *vpp; 417 } else { 418 if (uppervp != NULL) 419 VOP_UNLOCK(uppervp); 420 if (lowervp != NULL) 421 VOP_UNLOCK(lowervp); 422 *vpp = vp; 423 } 424 425 unionfs_nodeget_out: 426 if (lkflags & LK_TYPE_MASK) 427 vn_lock(vp, lkflags | LK_RETRY); 428 429 return (0); 430 } 431 432 /* 433 * Clean up the unionfs node. 434 */ 435 void 436 unionfs_noderem(struct vnode *vp) 437 { 438 struct unionfs_node *unp, *unp_t1, *unp_t2; 439 struct unionfs_node_hashhead *hd; 440 struct unionfs_node_status *unsp, *unsp_tmp; 441 struct vnode *lvp; 442 struct vnode *uvp; 443 struct vnode *dvp; 444 int count; 445 int writerefs; 446 447 /* 448 * The root vnode lock may be recursed during unmount, because 449 * it may share the same lock as the unionfs mount's covered vnode, 450 * which is locked across VFS_UNMOUNT(). This lock will then be 451 * recursively taken during the vflush() issued by unionfs_unmount(). 452 * But we still only need to lock the unionfs lock once, because only 453 * one of those lock operations was taken against a unionfs vnode and 454 * will be undone against a unionfs vnode. 455 */ 456 KASSERT(vp->v_vnlock->lk_recurse == 0 || (vp->v_vflag & VV_ROOT) != 0, 457 ("%s: vnode %p locked recursively", __func__, vp)); 458 if (lockmgr(&vp->v_lock, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 459 panic("%s: failed to acquire lock for vnode lock", __func__); 460 461 /* 462 * Use the interlock to protect the clearing of v_data to 463 * prevent faults in unionfs_lock(). 464 */ 465 VI_LOCK(vp); 466 unp = VTOUNIONFS(vp); 467 lvp = unp->un_lowervp; 468 uvp = unp->un_uppervp; 469 dvp = unp->un_dvp; 470 unp->un_lowervp = unp->un_uppervp = NULLVP; 471 vp->v_vnlock = &(vp->v_lock); 472 vp->v_data = NULL; 473 vp->v_object = NULL; 474 if (unp->un_hashtbl != NULL) { 475 /* 476 * Clear out any cached child vnodes. This should only 477 * be necessary during forced unmount, when the vnode may 478 * be reclaimed with a non-zero use count. Otherwise the 479 * reference held by each child should prevent reclamation. 480 */ 481 for (count = 0; count <= UNIONFSHASHMASK; count++) { 482 hd = unp->un_hashtbl + count; 483 LIST_FOREACH_SAFE(unp_t1, hd, un_hash, unp_t2) { 484 LIST_REMOVE(unp_t1, un_hash); 485 unp_t1->un_hash.le_next = NULL; 486 unp_t1->un_hash.le_prev = NULL; 487 } 488 } 489 } 490 VI_UNLOCK(vp); 491 492 writerefs = atomic_load_int(&vp->v_writecount); 493 VNASSERT(writerefs >= 0, vp, 494 ("%s: write count %d, unexpected text ref", __func__, writerefs)); 495 /* 496 * If we were opened for write, we leased the write reference 497 * to the lower vnode. If this is a reclamation due to the 498 * forced unmount, undo the reference now. 499 */ 500 if (writerefs > 0) { 501 VNASSERT(uvp != NULL, vp, 502 ("%s: write reference without upper vnode", __func__)); 503 VOP_ADD_WRITECOUNT(uvp, -writerefs); 504 } 505 if (lvp != NULLVP) 506 VOP_UNLOCK(lvp); 507 if (uvp != NULLVP) 508 VOP_UNLOCK(uvp); 509 510 if (dvp != NULLVP) 511 unionfs_rem_cached_vnode(unp, dvp); 512 513 if (lvp != NULLVP) 514 vrele(lvp); 515 if (uvp != NULLVP) 516 vrele(uvp); 517 if (unp->un_path != NULL) { 518 free(unp->un_path, M_UNIONFSPATH); 519 unp->un_path = NULL; 520 unp->un_pathlen = 0; 521 } 522 523 if (unp->un_hashtbl != NULL) { 524 hashdestroy(unp->un_hashtbl, M_UNIONFSHASH, UNIONFSHASHMASK); 525 } 526 527 LIST_FOREACH_SAFE(unsp, &(unp->un_unshead), uns_list, unsp_tmp) { 528 LIST_REMOVE(unsp, uns_list); 529 free(unsp, M_TEMP); 530 } 531 if (dvp != NULLVP) { 532 mtx_lock(&unionfs_deferred_rele_lock); 533 STAILQ_INSERT_TAIL(&unionfs_deferred_rele_list, unp, un_rele); 534 mtx_unlock(&unionfs_deferred_rele_lock); 535 taskqueue_enqueue(taskqueue_unionfs_rele, 536 &unionfs_deferred_rele_task); 537 } else 538 free(unp, M_UNIONFSNODE); 539 } 540 541 /* 542 * Get the unionfs node status object for the vnode corresponding to unp, 543 * for the process that owns td. Allocate a new status object if one 544 * does not already exist. 545 */ 546 void 547 unionfs_get_node_status(struct unionfs_node *unp, struct thread *td, 548 struct unionfs_node_status **unspp) 549 { 550 struct unionfs_node_status *unsp; 551 pid_t pid; 552 553 pid = td->td_proc->p_pid; 554 555 KASSERT(NULL != unspp, ("%s: NULL status", __func__)); 556 ASSERT_VOP_ELOCKED(UNIONFSTOV(unp), __func__); 557 558 LIST_FOREACH(unsp, &(unp->un_unshead), uns_list) { 559 if (unsp->uns_pid == pid) { 560 *unspp = unsp; 561 return; 562 } 563 } 564 565 /* create a new unionfs node status */ 566 unsp = malloc(sizeof(struct unionfs_node_status), 567 M_TEMP, M_WAITOK | M_ZERO); 568 569 unsp->uns_pid = pid; 570 LIST_INSERT_HEAD(&(unp->un_unshead), unsp, uns_list); 571 572 *unspp = unsp; 573 } 574 575 /* 576 * Remove the unionfs node status, if you can. 577 * You need exclusive lock this vnode. 578 */ 579 void 580 unionfs_tryrem_node_status(struct unionfs_node *unp, 581 struct unionfs_node_status *unsp) 582 { 583 KASSERT(NULL != unsp, ("%s: NULL status", __func__)); 584 ASSERT_VOP_ELOCKED(UNIONFSTOV(unp), __func__); 585 586 if (0 < unsp->uns_lower_opencnt || 0 < unsp->uns_upper_opencnt) 587 return; 588 589 LIST_REMOVE(unsp, uns_list); 590 free(unsp, M_TEMP); 591 } 592 593 /* 594 * Create upper node attr. 595 */ 596 void 597 unionfs_create_uppervattr_core(struct unionfs_mount *ump, struct vattr *lva, 598 struct vattr *uva, struct thread *td) 599 { 600 VATTR_NULL(uva); 601 uva->va_type = lva->va_type; 602 uva->va_atime = lva->va_atime; 603 uva->va_mtime = lva->va_mtime; 604 uva->va_ctime = lva->va_ctime; 605 606 switch (ump->um_copymode) { 607 case UNIONFS_TRANSPARENT: 608 uva->va_mode = lva->va_mode; 609 uva->va_uid = lva->va_uid; 610 uva->va_gid = lva->va_gid; 611 break; 612 case UNIONFS_MASQUERADE: 613 if (ump->um_uid == lva->va_uid) { 614 uva->va_mode = lva->va_mode & 077077; 615 uva->va_mode |= (lva->va_type == VDIR ? 616 ump->um_udir : ump->um_ufile) & 0700; 617 uva->va_uid = lva->va_uid; 618 uva->va_gid = lva->va_gid; 619 } else { 620 uva->va_mode = (lva->va_type == VDIR ? 621 ump->um_udir : ump->um_ufile); 622 uva->va_uid = ump->um_uid; 623 uva->va_gid = ump->um_gid; 624 } 625 break; 626 default: /* UNIONFS_TRADITIONAL */ 627 uva->va_mode = 0777 & ~td->td_proc->p_pd->pd_cmask; 628 uva->va_uid = ump->um_uid; 629 uva->va_gid = ump->um_gid; 630 break; 631 } 632 } 633 634 /* 635 * Create upper node attr. 636 */ 637 int 638 unionfs_create_uppervattr(struct unionfs_mount *ump, struct vnode *lvp, 639 struct vattr *uva, struct ucred *cred, struct thread *td) 640 { 641 struct vattr lva; 642 int error; 643 644 if ((error = VOP_GETATTR(lvp, &lva, cred))) 645 return (error); 646 647 unionfs_create_uppervattr_core(ump, &lva, uva, td); 648 649 return (error); 650 } 651 652 /* 653 * relookup 654 * 655 * dvp should be locked on entry and will be locked on return. 656 * 657 * If an error is returned, *vpp will be invalid, otherwise it will hold a 658 * locked, referenced vnode. If *vpp == dvp then remember that only one 659 * LK_EXCLUSIVE lock is held. 660 */ 661 int 662 unionfs_relookup(struct vnode *dvp, struct vnode **vpp, 663 struct componentname *cnp, struct componentname *cn, struct thread *td, 664 char *path, int pathlen, u_long nameiop) 665 { 666 int error; 667 bool refstart; 668 669 cn->cn_namelen = pathlen; 670 cn->cn_pnbuf = path; 671 cn->cn_nameiop = nameiop; 672 cn->cn_flags = (LOCKPARENT | LOCKLEAF | ISLASTCN); 673 cn->cn_lkflags = LK_EXCLUSIVE; 674 cn->cn_cred = cnp->cn_cred; 675 cn->cn_nameptr = cn->cn_pnbuf; 676 677 refstart = false; 678 if (nameiop == DELETE) { 679 cn->cn_flags |= (cnp->cn_flags & DOWHITEOUT); 680 } else if (nameiop == RENAME) { 681 refstart = true; 682 } else if (nameiop == CREATE) { 683 cn->cn_flags |= NOCACHE; 684 } 685 686 vref(dvp); 687 VOP_UNLOCK(dvp); 688 689 if ((error = vfs_relookup(dvp, vpp, cn, refstart))) { 690 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); 691 } else 692 vrele(dvp); 693 694 KASSERT(cn->cn_pnbuf == path, ("%s: cn_pnbuf changed", __func__)); 695 696 return (error); 697 } 698 699 /* 700 * relookup for CREATE namei operation. 701 * 702 * dvp is unionfs vnode. dvp should be locked. 703 * 704 * If it called 'unionfs_copyfile' function by unionfs_link etc, 705 * VOP_LOOKUP information is broken. 706 * So it need relookup in order to create link etc. 707 */ 708 int 709 unionfs_relookup_for_create(struct vnode *dvp, struct componentname *cnp, 710 struct thread *td) 711 { 712 struct vnode *udvp; 713 struct vnode *vp; 714 struct componentname cn; 715 int error; 716 717 udvp = UNIONFSVPTOUPPERVP(dvp); 718 vp = NULLVP; 719 720 error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr, 721 cnp->cn_namelen, CREATE); 722 if (error) 723 return (error); 724 725 if (vp != NULLVP) { 726 if (udvp == vp) 727 vrele(vp); 728 else 729 vput(vp); 730 731 error = EEXIST; 732 } 733 734 return (error); 735 } 736 737 /* 738 * relookup for DELETE namei operation. 739 * 740 * dvp is unionfs vnode. dvp should be locked. 741 */ 742 int 743 unionfs_relookup_for_delete(struct vnode *dvp, struct componentname *cnp, 744 struct thread *td) 745 { 746 struct vnode *udvp; 747 struct vnode *vp; 748 struct componentname cn; 749 int error; 750 751 udvp = UNIONFSVPTOUPPERVP(dvp); 752 vp = NULLVP; 753 754 error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr, 755 cnp->cn_namelen, DELETE); 756 if (error) 757 return (error); 758 759 if (vp == NULLVP) 760 error = ENOENT; 761 else { 762 if (udvp == vp) 763 vrele(vp); 764 else 765 vput(vp); 766 } 767 768 return (error); 769 } 770 771 /* 772 * relookup for RENAME namei operation. 773 * 774 * dvp is unionfs vnode. dvp should be locked. 775 */ 776 int 777 unionfs_relookup_for_rename(struct vnode *dvp, struct componentname *cnp, 778 struct thread *td) 779 { 780 struct vnode *udvp; 781 struct vnode *vp; 782 struct componentname cn; 783 int error; 784 785 udvp = UNIONFSVPTOUPPERVP(dvp); 786 vp = NULLVP; 787 788 error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr, 789 cnp->cn_namelen, RENAME); 790 if (error) 791 return (error); 792 793 if (vp != NULLVP) { 794 if (udvp == vp) 795 vrele(vp); 796 else 797 vput(vp); 798 } 799 800 return (error); 801 } 802 803 /* 804 * Update the unionfs_node. 805 * 806 * uvp is new locked upper vnode. unionfs vnode's lock will be exchanged to the 807 * uvp's lock and lower's lock will be unlocked. 808 */ 809 static void 810 unionfs_node_update(struct unionfs_node *unp, struct vnode *uvp, 811 struct thread *td) 812 { 813 struct unionfs_node_hashhead *hd; 814 struct vnode *vp; 815 struct vnode *lvp; 816 struct vnode *dvp; 817 unsigned count, lockrec; 818 819 vp = UNIONFSTOV(unp); 820 lvp = unp->un_lowervp; 821 ASSERT_VOP_ELOCKED(lvp, __func__); 822 ASSERT_VOP_ELOCKED(uvp, __func__); 823 dvp = unp->un_dvp; 824 825 VNASSERT(vp->v_writecount == 0, vp, 826 ("%s: non-zero writecount", __func__)); 827 /* 828 * Update the upper vnode's lock state to match the lower vnode, 829 * and then switch the unionfs vnode's lock to the upper vnode. 830 */ 831 lockrec = lvp->v_vnlock->lk_recurse; 832 for (count = 0; count < lockrec; count++) 833 vn_lock(uvp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY); 834 VI_LOCK(vp); 835 unp->un_uppervp = uvp; 836 vp->v_vnlock = uvp->v_vnlock; 837 VI_UNLOCK(vp); 838 839 /* 840 * Re-cache the unionfs vnode against the upper vnode 841 */ 842 if (dvp != NULLVP && vp->v_type == VDIR) { 843 VI_LOCK(dvp); 844 if (unp->un_hash.le_prev != NULL) { 845 LIST_REMOVE(unp, un_hash); 846 hd = unionfs_get_hashhead(dvp, uvp); 847 LIST_INSERT_HEAD(hd, unp, un_hash); 848 } 849 VI_UNLOCK(unp->un_dvp); 850 } 851 } 852 853 /* 854 * Create a new shadow dir. 855 * 856 * udvp should be locked on entry and will be locked on return. 857 * 858 * If no error returned, unp will be updated. 859 */ 860 int 861 unionfs_mkshadowdir(struct unionfs_mount *ump, struct vnode *udvp, 862 struct unionfs_node *unp, struct componentname *cnp, struct thread *td) 863 { 864 struct vnode *lvp; 865 struct vnode *uvp; 866 struct vattr va; 867 struct vattr lva; 868 struct nameidata nd; 869 struct mount *mp; 870 struct ucred *cred; 871 struct ucred *credbk; 872 struct uidinfo *rootinfo; 873 int error; 874 875 if (unp->un_uppervp != NULLVP) 876 return (EEXIST); 877 878 lvp = unp->un_lowervp; 879 uvp = NULLVP; 880 credbk = cnp->cn_cred; 881 882 /* Authority change to root */ 883 rootinfo = uifind((uid_t)0); 884 cred = crdup(cnp->cn_cred); 885 /* 886 * The calls to chgproccnt() are needed to compensate for change_ruid() 887 * calling chgproccnt(). 888 */ 889 chgproccnt(cred->cr_ruidinfo, 1, 0); 890 change_euid(cred, rootinfo); 891 change_ruid(cred, rootinfo); 892 change_svuid(cred, (uid_t)0); 893 uifree(rootinfo); 894 cnp->cn_cred = cred; 895 896 memset(&nd.ni_cnd, 0, sizeof(struct componentname)); 897 NDPREINIT(&nd); 898 899 if ((error = VOP_GETATTR(lvp, &lva, cnp->cn_cred))) 900 goto unionfs_mkshadowdir_abort; 901 902 if ((error = unionfs_relookup(udvp, &uvp, cnp, &nd.ni_cnd, td, 903 cnp->cn_nameptr, cnp->cn_namelen, CREATE))) 904 goto unionfs_mkshadowdir_abort; 905 if (uvp != NULLVP) { 906 if (udvp == uvp) 907 vrele(uvp); 908 else 909 vput(uvp); 910 911 error = EEXIST; 912 goto unionfs_mkshadowdir_abort; 913 } 914 915 if ((error = vn_start_write(udvp, &mp, V_WAIT | V_PCATCH))) 916 goto unionfs_mkshadowdir_abort; 917 unionfs_create_uppervattr_core(ump, &lva, &va, td); 918 919 error = VOP_MKDIR(udvp, &uvp, &nd.ni_cnd, &va); 920 921 if (!error) { 922 unionfs_node_update(unp, uvp, td); 923 924 /* 925 * XXX The bug which cannot set uid/gid was corrected. 926 * Ignore errors. 927 */ 928 va.va_type = VNON; 929 VOP_SETATTR(uvp, &va, nd.ni_cnd.cn_cred); 930 } 931 vn_finished_write(mp); 932 933 unionfs_mkshadowdir_abort: 934 cnp->cn_cred = credbk; 935 chgproccnt(cred->cr_ruidinfo, -1, 0); 936 crfree(cred); 937 938 return (error); 939 } 940 941 /* 942 * Create a new whiteout. 943 * 944 * dvp should be locked on entry and will be locked on return. 945 */ 946 int 947 unionfs_mkwhiteout(struct vnode *dvp, struct componentname *cnp, 948 struct thread *td, char *path, int pathlen) 949 { 950 struct vnode *wvp; 951 struct nameidata nd; 952 struct mount *mp; 953 int error; 954 955 wvp = NULLVP; 956 NDPREINIT(&nd); 957 if ((error = unionfs_relookup(dvp, &wvp, cnp, &nd.ni_cnd, td, path, 958 pathlen, CREATE))) { 959 return (error); 960 } 961 if (wvp != NULLVP) { 962 if (dvp == wvp) 963 vrele(wvp); 964 else 965 vput(wvp); 966 967 return (EEXIST); 968 } 969 970 if ((error = vn_start_write(dvp, &mp, V_WAIT | V_PCATCH))) 971 goto unionfs_mkwhiteout_free_out; 972 error = VOP_WHITEOUT(dvp, &nd.ni_cnd, CREATE); 973 974 vn_finished_write(mp); 975 976 unionfs_mkwhiteout_free_out: 977 return (error); 978 } 979 980 /* 981 * Create a new vnode for create a new shadow file. 982 * 983 * If an error is returned, *vpp will be invalid, otherwise it will hold a 984 * locked, referenced and opened vnode. 985 * 986 * unp is never updated. 987 */ 988 static int 989 unionfs_vn_create_on_upper(struct vnode **vpp, struct vnode *udvp, 990 struct unionfs_node *unp, struct vattr *uvap, struct thread *td) 991 { 992 struct unionfs_mount *ump; 993 struct vnode *vp; 994 struct vnode *lvp; 995 struct ucred *cred; 996 struct vattr lva; 997 struct nameidata nd; 998 int fmode; 999 int error; 1000 1001 ump = MOUNTTOUNIONFSMOUNT(UNIONFSTOV(unp)->v_mount); 1002 vp = NULLVP; 1003 lvp = unp->un_lowervp; 1004 cred = td->td_ucred; 1005 fmode = FFLAGS(O_WRONLY | O_CREAT | O_TRUNC | O_EXCL); 1006 error = 0; 1007 1008 if ((error = VOP_GETATTR(lvp, &lva, cred)) != 0) 1009 return (error); 1010 unionfs_create_uppervattr_core(ump, &lva, uvap, td); 1011 1012 if (unp->un_path == NULL) 1013 panic("%s: NULL un_path", __func__); 1014 1015 nd.ni_cnd.cn_namelen = unp->un_pathlen; 1016 nd.ni_cnd.cn_pnbuf = unp->un_path; 1017 nd.ni_cnd.cn_nameiop = CREATE; 1018 nd.ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF | ISLASTCN; 1019 nd.ni_cnd.cn_lkflags = LK_EXCLUSIVE; 1020 nd.ni_cnd.cn_cred = cred; 1021 nd.ni_cnd.cn_nameptr = nd.ni_cnd.cn_pnbuf; 1022 NDPREINIT(&nd); 1023 1024 vref(udvp); 1025 if ((error = vfs_relookup(udvp, &vp, &nd.ni_cnd, false)) != 0) 1026 goto unionfs_vn_create_on_upper_free_out2; 1027 vrele(udvp); 1028 1029 if (vp != NULLVP) { 1030 if (vp == udvp) 1031 vrele(vp); 1032 else 1033 vput(vp); 1034 error = EEXIST; 1035 goto unionfs_vn_create_on_upper_free_out1; 1036 } 1037 1038 if ((error = VOP_CREATE(udvp, &vp, &nd.ni_cnd, uvap)) != 0) 1039 goto unionfs_vn_create_on_upper_free_out1; 1040 1041 if ((error = VOP_OPEN(vp, fmode, cred, td, NULL)) != 0) { 1042 vput(vp); 1043 goto unionfs_vn_create_on_upper_free_out1; 1044 } 1045 error = VOP_ADD_WRITECOUNT(vp, 1); 1046 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 1047 __func__, vp, vp->v_writecount); 1048 if (error == 0) { 1049 *vpp = vp; 1050 } else { 1051 VOP_CLOSE(vp, fmode, cred, td); 1052 } 1053 1054 unionfs_vn_create_on_upper_free_out1: 1055 VOP_UNLOCK(udvp); 1056 1057 unionfs_vn_create_on_upper_free_out2: 1058 KASSERT(nd.ni_cnd.cn_pnbuf == unp->un_path, 1059 ("%s: cn_pnbuf changed", __func__)); 1060 1061 return (error); 1062 } 1063 1064 /* 1065 * Copy from lvp to uvp. 1066 * 1067 * lvp and uvp should be locked and opened on entry and will be locked and 1068 * opened on return. 1069 */ 1070 static int 1071 unionfs_copyfile_core(struct vnode *lvp, struct vnode *uvp, 1072 struct ucred *cred, struct thread *td) 1073 { 1074 char *buf; 1075 struct uio uio; 1076 struct iovec iov; 1077 off_t offset; 1078 int count; 1079 int error; 1080 int bufoffset; 1081 1082 error = 0; 1083 memset(&uio, 0, sizeof(uio)); 1084 1085 uio.uio_td = td; 1086 uio.uio_segflg = UIO_SYSSPACE; 1087 uio.uio_offset = 0; 1088 1089 buf = malloc(MAXBSIZE, M_TEMP, M_WAITOK); 1090 1091 while (error == 0) { 1092 offset = uio.uio_offset; 1093 1094 uio.uio_iov = &iov; 1095 uio.uio_iovcnt = 1; 1096 iov.iov_base = buf; 1097 iov.iov_len = MAXBSIZE; 1098 uio.uio_resid = iov.iov_len; 1099 uio.uio_rw = UIO_READ; 1100 1101 if ((error = VOP_READ(lvp, &uio, 0, cred)) != 0) 1102 break; 1103 if ((count = MAXBSIZE - uio.uio_resid) == 0) 1104 break; 1105 1106 bufoffset = 0; 1107 while (bufoffset < count) { 1108 uio.uio_iov = &iov; 1109 uio.uio_iovcnt = 1; 1110 iov.iov_base = buf + bufoffset; 1111 iov.iov_len = count - bufoffset; 1112 uio.uio_offset = offset + bufoffset; 1113 uio.uio_resid = iov.iov_len; 1114 uio.uio_rw = UIO_WRITE; 1115 1116 if ((error = VOP_WRITE(uvp, &uio, 0, cred)) != 0) 1117 break; 1118 1119 bufoffset += (count - bufoffset) - uio.uio_resid; 1120 } 1121 1122 uio.uio_offset = offset + bufoffset; 1123 } 1124 1125 free(buf, M_TEMP); 1126 1127 return (error); 1128 } 1129 1130 /* 1131 * Copy file from lower to upper. 1132 * 1133 * If you need copy of the contents, set 1 to docopy. Otherwise, set 0 to 1134 * docopy. 1135 * 1136 * If no error returned, unp will be updated. 1137 */ 1138 int 1139 unionfs_copyfile(struct unionfs_node *unp, int docopy, struct ucred *cred, 1140 struct thread *td) 1141 { 1142 struct mount *mp; 1143 struct vnode *udvp; 1144 struct vnode *lvp; 1145 struct vnode *uvp; 1146 struct vattr uva; 1147 int error; 1148 1149 lvp = unp->un_lowervp; 1150 uvp = NULLVP; 1151 1152 if ((UNIONFSTOV(unp)->v_mount->mnt_flag & MNT_RDONLY)) 1153 return (EROFS); 1154 if (unp->un_dvp == NULLVP) 1155 return (EINVAL); 1156 if (unp->un_uppervp != NULLVP) 1157 return (EEXIST); 1158 udvp = VTOUNIONFS(unp->un_dvp)->un_uppervp; 1159 if (udvp == NULLVP) 1160 return (EROFS); 1161 if ((udvp->v_mount->mnt_flag & MNT_RDONLY)) 1162 return (EROFS); 1163 1164 error = VOP_ACCESS(lvp, VREAD, cred, td); 1165 if (error != 0) 1166 return (error); 1167 1168 if ((error = vn_start_write(udvp, &mp, V_WAIT | V_PCATCH)) != 0) 1169 return (error); 1170 error = unionfs_vn_create_on_upper(&uvp, udvp, unp, &uva, td); 1171 if (error != 0) { 1172 vn_finished_write(mp); 1173 return (error); 1174 } 1175 1176 if (docopy != 0) { 1177 error = VOP_OPEN(lvp, FREAD, cred, td, NULL); 1178 if (error == 0) { 1179 error = unionfs_copyfile_core(lvp, uvp, cred, td); 1180 VOP_CLOSE(lvp, FREAD, cred, td); 1181 } 1182 } 1183 VOP_CLOSE(uvp, FWRITE, cred, td); 1184 VOP_ADD_WRITECOUNT_CHECKED(uvp, -1); 1185 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 1186 __func__, uvp, uvp->v_writecount); 1187 1188 vn_finished_write(mp); 1189 1190 if (error == 0) { 1191 /* Reset the attributes. Ignore errors. */ 1192 uva.va_type = VNON; 1193 VOP_SETATTR(uvp, &uva, cred); 1194 } 1195 1196 unionfs_node_update(unp, uvp, td); 1197 1198 return (error); 1199 } 1200 1201 /* 1202 * It checks whether vp can rmdir. (check empty) 1203 * 1204 * vp is unionfs vnode. 1205 * vp should be locked. 1206 */ 1207 int 1208 unionfs_check_rmdir(struct vnode *vp, struct ucred *cred, struct thread *td) 1209 { 1210 struct vnode *uvp; 1211 struct vnode *lvp; 1212 struct vnode *tvp; 1213 struct dirent *dp; 1214 struct dirent *edp; 1215 struct componentname cn; 1216 struct iovec iov; 1217 struct uio uio; 1218 struct vattr va; 1219 int error; 1220 int eofflag; 1221 int lookuperr; 1222 1223 /* 1224 * The size of buf needs to be larger than DIRBLKSIZ. 1225 */ 1226 char buf[256 * 6]; 1227 1228 ASSERT_VOP_ELOCKED(vp, __func__); 1229 1230 eofflag = 0; 1231 uvp = UNIONFSVPTOUPPERVP(vp); 1232 lvp = UNIONFSVPTOLOWERVP(vp); 1233 1234 /* check opaque */ 1235 if ((error = VOP_GETATTR(uvp, &va, cred)) != 0) 1236 return (error); 1237 if (va.va_flags & OPAQUE) 1238 return (0); 1239 1240 /* open vnode */ 1241 #ifdef MAC 1242 if ((error = mac_vnode_check_open(cred, vp, VEXEC|VREAD)) != 0) 1243 return (error); 1244 #endif 1245 if ((error = VOP_ACCESS(vp, VEXEC|VREAD, cred, td)) != 0) 1246 return (error); 1247 if ((error = VOP_OPEN(vp, FREAD, cred, td, NULL)) != 0) 1248 return (error); 1249 1250 uio.uio_rw = UIO_READ; 1251 uio.uio_segflg = UIO_SYSSPACE; 1252 uio.uio_td = td; 1253 uio.uio_offset = 0; 1254 1255 #ifdef MAC 1256 error = mac_vnode_check_readdir(td->td_ucred, lvp); 1257 #endif 1258 while (!error && !eofflag) { 1259 iov.iov_base = buf; 1260 iov.iov_len = sizeof(buf); 1261 uio.uio_iov = &iov; 1262 uio.uio_iovcnt = 1; 1263 uio.uio_resid = iov.iov_len; 1264 1265 error = VOP_READDIR(lvp, &uio, cred, &eofflag, NULL, NULL); 1266 if (error != 0) 1267 break; 1268 KASSERT(eofflag != 0 || uio.uio_resid < sizeof(buf), 1269 ("%s: empty read from lower FS", __func__)); 1270 1271 edp = (struct dirent*)&buf[sizeof(buf) - uio.uio_resid]; 1272 for (dp = (struct dirent*)buf; !error && dp < edp; 1273 dp = (struct dirent*)((caddr_t)dp + dp->d_reclen)) { 1274 if (dp->d_type == DT_WHT || dp->d_fileno == 0 || 1275 (dp->d_namlen == 1 && dp->d_name[0] == '.') || 1276 (dp->d_namlen == 2 && !bcmp(dp->d_name, "..", 2))) 1277 continue; 1278 1279 cn.cn_namelen = dp->d_namlen; 1280 cn.cn_pnbuf = NULL; 1281 cn.cn_nameptr = dp->d_name; 1282 cn.cn_nameiop = LOOKUP; 1283 cn.cn_flags = LOCKPARENT | LOCKLEAF | RDONLY | ISLASTCN; 1284 cn.cn_lkflags = LK_EXCLUSIVE; 1285 cn.cn_cred = cred; 1286 1287 /* 1288 * check entry in lower. 1289 * Sometimes, readdir function returns 1290 * wrong entry. 1291 */ 1292 lookuperr = VOP_LOOKUP(lvp, &tvp, &cn); 1293 1294 if (!lookuperr) 1295 vput(tvp); 1296 else 1297 continue; /* skip entry */ 1298 1299 /* 1300 * check entry 1301 * If it has no exist/whiteout entry in upper, 1302 * directory is not empty. 1303 */ 1304 cn.cn_flags = LOCKPARENT | LOCKLEAF | RDONLY | ISLASTCN; 1305 lookuperr = VOP_LOOKUP(uvp, &tvp, &cn); 1306 1307 if (!lookuperr) 1308 vput(tvp); 1309 1310 /* ignore exist or whiteout entry */ 1311 if (!lookuperr || 1312 (lookuperr == ENOENT && (cn.cn_flags & ISWHITEOUT))) 1313 continue; 1314 1315 error = ENOTEMPTY; 1316 } 1317 } 1318 1319 /* close vnode */ 1320 VOP_CLOSE(vp, FREAD, cred, td); 1321 1322 return (error); 1323 } 1324 1325