| 1 | /* |
| 2 | * Copyright (c) 1994 Jan-Simon Pendry |
| 3 | * Copyright (c) 1994 |
| 4 | * The Regents of the University of California. All rights reserved. |
| 5 | * |
| 6 | * This code is derived from software contributed to Berkeley by |
| 7 | * Jan-Simon Pendry. |
| 8 | * |
| 9 | * Redistribution and use in source and binary forms, with or without |
| 10 | * modification, are permitted provided that the following conditions |
| 11 | * are met: |
| 12 | * 1. Redistributions of source code must retain the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer. |
| 14 | * 2. Redistributions in binary form must reproduce the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer in the |
| 16 | * documentation and/or other materials provided with the distribution. |
| 17 | * 3. All advertising materials mentioning features or use of this software |
| 18 | * must display the following acknowledgement: |
| 19 | * This product includes software developed by the University of |
| 20 | * California, Berkeley and its contributors. |
| 21 | * 4. 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: src/sys/miscfs/union/union_subr.c,v 1.43.2.2 2001/12/25 01:44:45 dillon Exp $ |
| 39 | */ |
| 40 | |
| 41 | #include <sys/param.h> |
| 42 | #include <sys/systm.h> |
| 43 | #include <sys/kernel.h> |
| 44 | #include <sys/vnode.h> |
| 45 | #include <sys/proc.h> |
| 46 | #include <sys/namei.h> |
| 47 | #include <sys/malloc.h> |
| 48 | #include <sys/fcntl.h> |
| 49 | #include <sys/file.h> |
| 50 | #include <sys/filedesc.h> |
| 51 | #include <sys/module.h> |
| 52 | #include <sys/mount.h> |
| 53 | #include <sys/stat.h> |
| 54 | #include <vm/vm.h> |
| 55 | #include <vm/vm_extern.h> /* for vnode_pager_setsize */ |
| 56 | #include <vm/vm_zone.h> |
| 57 | #include <vm/vm_object.h> /* for vm cache coherency */ |
| 58 | #include "union.h" |
| 59 | |
| 60 | extern int union_init (void); |
| 61 | |
| 62 | /* must be power of two, otherwise change UNION_HASH() */ |
| 63 | #define NHASH 32 |
| 64 | |
| 65 | /* unsigned int ... */ |
| 66 | #define UNION_HASH(u, l) \ |
| 67 | (((((uintptr_t) (u)) + ((uintptr_t) l)) >> 8) & (NHASH-1)) |
| 68 | |
| 69 | static LIST_HEAD(unhead, union_node) unhead[NHASH]; |
| 70 | static int unvplock[NHASH]; |
| 71 | |
| 72 | static void union_dircache_r (struct vnode *vp, struct vnode ***vppp, |
| 73 | int *cntp); |
| 74 | static int union_list_lock (int ix); |
| 75 | static void union_list_unlock (int ix); |
| 76 | static int union_relookup (struct union_mount *um, struct vnode *dvp, |
| 77 | struct vnode **vpp, |
| 78 | struct componentname *cnp, |
| 79 | struct componentname *cn, char *path, |
| 80 | int pathlen); |
| 81 | static void union_updatevp (struct union_node *un, |
| 82 | struct vnode *uppervp, |
| 83 | struct vnode *lowervp); |
| 84 | static void union_newlower (struct union_node *, struct vnode *); |
| 85 | static void union_newupper (struct union_node *, struct vnode *); |
| 86 | static int union_copyfile (struct vnode *, struct vnode *, |
| 87 | struct ucred *, struct thread *); |
| 88 | static int union_vn_create (struct vnode **, struct union_node *, |
| 89 | struct thread *); |
| 90 | static int union_vn_close (struct vnode *, int, struct ucred *); |
| 91 | |
| 92 | int |
| 93 | union_init(void) |
| 94 | { |
| 95 | int i; |
| 96 | |
| 97 | for (i = 0; i < NHASH; i++) |
| 98 | LIST_INIT(&unhead[i]); |
| 99 | bzero((caddr_t)unvplock, sizeof(unvplock)); |
| 100 | return (0); |
| 101 | } |
| 102 | |
| 103 | static int |
| 104 | union_list_lock(int ix) |
| 105 | { |
| 106 | if (unvplock[ix] & UNVP_LOCKED) { |
| 107 | unvplock[ix] |= UNVP_WANT; |
| 108 | (void) tsleep((caddr_t) &unvplock[ix], 0, "unllck", 0); |
| 109 | return (1); |
| 110 | } |
| 111 | unvplock[ix] |= UNVP_LOCKED; |
| 112 | return (0); |
| 113 | } |
| 114 | |
| 115 | static void |
| 116 | union_list_unlock(int ix) |
| 117 | { |
| 118 | unvplock[ix] &= ~UNVP_LOCKED; |
| 119 | |
| 120 | if (unvplock[ix] & UNVP_WANT) { |
| 121 | unvplock[ix] &= ~UNVP_WANT; |
| 122 | wakeup((caddr_t) &unvplock[ix]); |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | /* |
| 127 | * union_updatevp: |
| 128 | * |
| 129 | * The uppervp, if not NULL, must be referenced and not locked by us |
| 130 | * The lowervp, if not NULL, must be referenced. |
| 131 | * |
| 132 | * if uppervp and lowervp match pointers already installed, nothing |
| 133 | * happens. The passed vp's (when matching) are not adjusted. This |
| 134 | * routine may only be called by union_newupper() and union_newlower(). |
| 135 | */ |
| 136 | |
| 137 | static void |
| 138 | union_updatevp(struct union_node *un, struct vnode *uppervp, |
| 139 | struct vnode *lowervp) |
| 140 | { |
| 141 | int ohash = UNION_HASH(un->un_uppervp, un->un_lowervp); |
| 142 | int nhash = UNION_HASH(uppervp, lowervp); |
| 143 | int docache = (lowervp != NULLVP || uppervp != NULLVP); |
| 144 | int lhash, uhash; |
| 145 | |
| 146 | /* |
| 147 | * Ensure locking is ordered from lower to higher |
| 148 | * to avoid deadlocks. |
| 149 | */ |
| 150 | if (nhash < ohash) { |
| 151 | lhash = nhash; |
| 152 | uhash = ohash; |
| 153 | } else { |
| 154 | lhash = ohash; |
| 155 | uhash = nhash; |
| 156 | } |
| 157 | |
| 158 | if (lhash != uhash) { |
| 159 | while (union_list_lock(lhash)) |
| 160 | continue; |
| 161 | } |
| 162 | |
| 163 | while (union_list_lock(uhash)) |
| 164 | continue; |
| 165 | |
| 166 | if (ohash != nhash || !docache) { |
| 167 | if (un->un_flags & UN_CACHED) { |
| 168 | un->un_flags &= ~UN_CACHED; |
| 169 | LIST_REMOVE(un, un_cache); |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | if (ohash != nhash) |
| 174 | union_list_unlock(ohash); |
| 175 | |
| 176 | if (un->un_lowervp != lowervp) { |
| 177 | if (un->un_lowervp) { |
| 178 | vrele(un->un_lowervp); |
| 179 | if (un->un_path) { |
| 180 | kfree(un->un_path, M_TEMP); |
| 181 | un->un_path = 0; |
| 182 | } |
| 183 | } |
| 184 | un->un_lowervp = lowervp; |
| 185 | un->un_lowersz = VNOVAL; |
| 186 | } |
| 187 | |
| 188 | if (un->un_uppervp != uppervp) { |
| 189 | if (un->un_uppervp) |
| 190 | vrele(un->un_uppervp); |
| 191 | un->un_uppervp = uppervp; |
| 192 | un->un_uppersz = VNOVAL; |
| 193 | } |
| 194 | |
| 195 | if (docache && (ohash != nhash)) { |
| 196 | LIST_INSERT_HEAD(&unhead[nhash], un, un_cache); |
| 197 | un->un_flags |= UN_CACHED; |
| 198 | } |
| 199 | |
| 200 | union_list_unlock(nhash); |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * Set a new lowervp. The passed lowervp must be referenced and will be |
| 205 | * stored in the vp in a referenced state. |
| 206 | */ |
| 207 | |
| 208 | static void |
| 209 | union_newlower(struct union_node *un, struct vnode *lowervp) |
| 210 | { |
| 211 | union_updatevp(un, un->un_uppervp, lowervp); |
| 212 | } |
| 213 | |
| 214 | /* |
| 215 | * Set a new uppervp. The passed uppervp must be locked and will be |
| 216 | * stored in the vp in a locked state. The caller should not unlock |
| 217 | * uppervp. |
| 218 | */ |
| 219 | |
| 220 | static void |
| 221 | union_newupper(struct union_node *un, struct vnode *uppervp) |
| 222 | { |
| 223 | union_updatevp(un, uppervp, un->un_lowervp); |
| 224 | } |
| 225 | |
| 226 | /* |
| 227 | * Keep track of size changes in the underlying vnodes. |
| 228 | * If the size changes, then callback to the vm layer |
| 229 | * giving priority to the upper layer size. |
| 230 | */ |
| 231 | void |
| 232 | union_newsize(struct vnode *vp, off_t uppersz, off_t lowersz) |
| 233 | { |
| 234 | struct union_node *un; |
| 235 | off_t sz; |
| 236 | |
| 237 | /* only interested in regular files */ |
| 238 | if (vp->v_type != VREG) |
| 239 | return; |
| 240 | |
| 241 | un = VTOUNION(vp); |
| 242 | sz = VNOVAL; |
| 243 | |
| 244 | if ((uppersz != VNOVAL) && (un->un_uppersz != uppersz)) { |
| 245 | un->un_uppersz = uppersz; |
| 246 | if (sz == VNOVAL) |
| 247 | sz = un->un_uppersz; |
| 248 | } |
| 249 | |
| 250 | if ((lowersz != VNOVAL) && (un->un_lowersz != lowersz)) { |
| 251 | un->un_lowersz = lowersz; |
| 252 | if (sz == VNOVAL) |
| 253 | sz = un->un_lowersz; |
| 254 | } |
| 255 | |
| 256 | if (sz != VNOVAL) { |
| 257 | UDEBUG(("union: %s size now %ld\n", |
| 258 | (uppersz != VNOVAL ? "upper" : "lower"), (long)sz)); |
| 259 | vnode_pager_setsize(vp, sz); |
| 260 | } |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * union_allocvp: allocate a union_node and associate it with a |
| 265 | * parent union_node and one or two vnodes. |
| 266 | * |
| 267 | * vpp Holds the returned vnode locked and referenced if no |
| 268 | * error occurs. |
| 269 | * |
| 270 | * mp Holds the mount point. mp may or may not be busied. |
| 271 | * allocvp makes no changes to mp. |
| 272 | * |
| 273 | * dvp Holds the parent union_node to the one we wish to create. |
| 274 | * XXX may only be used to traverse an uncopied lowervp-based |
| 275 | * tree? XXX |
| 276 | * |
| 277 | * dvp may or may not be locked. allocvp makes no changes |
| 278 | * to dvp. |
| 279 | * |
| 280 | * upperdvp Holds the parent vnode to uppervp, generally used along |
| 281 | * with path component information to create a shadow of |
| 282 | * lowervp when uppervp does not exist. |
| 283 | * |
| 284 | * upperdvp is referenced but unlocked on entry, and will be |
| 285 | * dereferenced on return. |
| 286 | * |
| 287 | * uppervp Holds the new uppervp vnode to be stored in the |
| 288 | * union_node we are allocating. uppervp is referenced but |
| 289 | * not locked, and will be dereferenced on return. |
| 290 | * |
| 291 | * lowervp Holds the new lowervp vnode to be stored in the |
| 292 | * union_node we are allocating. lowervp is referenced but |
| 293 | * not locked, and will be dereferenced on return. |
| 294 | * |
| 295 | * cnp Holds path component information to be coupled with |
| 296 | * lowervp and upperdvp to allow unionfs to create an uppervp |
| 297 | * later on. Only used if lowervp is valid. The conents |
| 298 | * of cnp is only valid for the duration of the call. |
| 299 | * |
| 300 | * docache Determine whether this node should be entered in the |
| 301 | * cache or whether it should be destroyed as soon as possible. |
| 302 | * |
| 303 | * all union_nodes are maintained on a singly-linked |
| 304 | * list. new nodes are only allocated when they cannot |
| 305 | * be found on this list. entries on the list are |
| 306 | * removed when the vfs reclaim entry is called. |
| 307 | * |
| 308 | * a single lock is kept for the entire list. this is |
| 309 | * needed because the getnewvnode() function can block |
| 310 | * waiting for a vnode to become free, in which case there |
| 311 | * may be more than one process trying to get the same |
| 312 | * vnode. this lock is only taken if we are going to |
| 313 | * call getnewvnode, since the kernel itself is single-threaded. |
| 314 | * |
| 315 | * if an entry is found on the list, then call vget() to |
| 316 | * take a reference. this is done because there may be |
| 317 | * zero references to it and so it needs to removed from |
| 318 | * the vnode free list. |
| 319 | */ |
| 320 | |
| 321 | int |
| 322 | union_allocvp(struct vnode **vpp, |
| 323 | struct mount *mp, |
| 324 | struct vnode *dvp, /* parent union vnode */ |
| 325 | struct vnode *upperdvp, /* parent vnode of uppervp */ |
| 326 | struct componentname *cnp, /* may be null */ |
| 327 | struct vnode *uppervp, /* may be null */ |
| 328 | struct vnode *lowervp, /* may be null */ |
| 329 | int docache) |
| 330 | { |
| 331 | int error; |
| 332 | struct union_node *un = NULL; |
| 333 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 334 | struct thread *td = (cnp) ? cnp->cn_td : curthread; /* XXX */ |
| 335 | int hash = 0; |
| 336 | int vflag; |
| 337 | int try; |
| 338 | |
| 339 | if (uppervp == NULLVP && lowervp == NULLVP) |
| 340 | panic("union: unidentifiable allocation"); |
| 341 | |
| 342 | if (uppervp && lowervp && (uppervp->v_type != lowervp->v_type)) { |
| 343 | vrele(lowervp); |
| 344 | lowervp = NULLVP; |
| 345 | } |
| 346 | |
| 347 | /* detect the root vnode (and aliases) */ |
| 348 | vflag = 0; |
| 349 | if ((uppervp == um->um_uppervp) && |
| 350 | ((lowervp == NULLVP) || lowervp == um->um_lowervp)) { |
| 351 | if (lowervp == NULLVP) { |
| 352 | lowervp = um->um_lowervp; |
| 353 | if (lowervp != NULLVP) |
| 354 | vref(lowervp); |
| 355 | } |
| 356 | vflag = VROOT; |
| 357 | } |
| 358 | |
| 359 | loop: |
| 360 | if (!docache) { |
| 361 | un = NULL; |
| 362 | } else for (try = 0; try < 3; try++) { |
| 363 | switch (try) { |
| 364 | case 0: |
| 365 | if (lowervp == NULLVP) |
| 366 | continue; |
| 367 | hash = UNION_HASH(uppervp, lowervp); |
| 368 | break; |
| 369 | |
| 370 | case 1: |
| 371 | if (uppervp == NULLVP) |
| 372 | continue; |
| 373 | hash = UNION_HASH(uppervp, NULLVP); |
| 374 | break; |
| 375 | |
| 376 | case 2: |
| 377 | if (lowervp == NULLVP) |
| 378 | continue; |
| 379 | hash = UNION_HASH(NULLVP, lowervp); |
| 380 | break; |
| 381 | } |
| 382 | |
| 383 | while (union_list_lock(hash)) |
| 384 | continue; |
| 385 | |
| 386 | for (un = unhead[hash].lh_first; un != NULL; |
| 387 | un = un->un_cache.le_next) { |
| 388 | if ((un->un_lowervp == lowervp || |
| 389 | un->un_lowervp == NULLVP) && |
| 390 | (un->un_uppervp == uppervp || |
| 391 | un->un_uppervp == NULLVP) && |
| 392 | (UNIONTOV(un)->v_mount == mp)) { |
| 393 | if (vget(UNIONTOV(un), LK_EXCLUSIVE|LK_SLEEPFAIL)) { |
| 394 | union_list_unlock(hash); |
| 395 | goto loop; |
| 396 | } |
| 397 | break; |
| 398 | } |
| 399 | } |
| 400 | |
| 401 | union_list_unlock(hash); |
| 402 | |
| 403 | if (un) |
| 404 | break; |
| 405 | } |
| 406 | |
| 407 | if (un) { |
| 408 | /* |
| 409 | * Obtain a lock on the union_node. Everything is unlocked |
| 410 | * except for dvp, so check that case. If they match, our |
| 411 | * new un is already locked. Otherwise we have to lock our |
| 412 | * new un. |
| 413 | * |
| 414 | * A potential deadlock situation occurs when we are holding |
| 415 | * one lock while trying to get another. We must follow |
| 416 | * strict ordering rules to avoid it. We try to locate dvp |
| 417 | * by scanning up from un_vnode, since the most likely |
| 418 | * scenario is un being under dvp. |
| 419 | */ |
| 420 | |
| 421 | if (dvp && un->un_vnode != dvp) { |
| 422 | struct vnode *scan = un->un_vnode; |
| 423 | |
| 424 | do { |
| 425 | scan = VTOUNION(scan)->un_pvp; |
| 426 | } while (scan && scan->v_tag == VT_UNION && scan != dvp); |
| 427 | if (scan != dvp) { |
| 428 | /* |
| 429 | * our new un is above dvp (we never saw dvp |
| 430 | * while moving up the tree). |
| 431 | */ |
| 432 | vref(dvp); |
| 433 | vn_unlock(dvp); |
| 434 | error = vn_lock(un->un_vnode, LK_EXCLUSIVE); |
| 435 | vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); |
| 436 | vrele(dvp); |
| 437 | } else { |
| 438 | /* |
| 439 | * our new un is under dvp |
| 440 | */ |
| 441 | error = vn_lock(un->un_vnode, LK_EXCLUSIVE); |
| 442 | } |
| 443 | } else if (dvp == NULLVP) { |
| 444 | /* |
| 445 | * dvp is NULL, we need to lock un. |
| 446 | */ |
| 447 | error = vn_lock(un->un_vnode, LK_EXCLUSIVE); |
| 448 | } else { |
| 449 | /* |
| 450 | * dvp == un->un_vnode, we are already locked. |
| 451 | */ |
| 452 | error = 0; |
| 453 | } |
| 454 | |
| 455 | if (error) |
| 456 | goto loop; |
| 457 | |
| 458 | /* |
| 459 | * At this point, the union_node is locked and referenced. |
| 460 | * |
| 461 | * uppervp is locked and referenced or NULL, lowervp is |
| 462 | * referenced or NULL. |
| 463 | */ |
| 464 | UDEBUG(("Modify existing un %p vn %p upper %p(refs %d) -> %p(refs %d)\n", |
| 465 | un, un->un_vnode, un->un_uppervp, |
| 466 | (un->un_uppervp ? un->un_uppervp->v_sysref.refcnt : -99), |
| 467 | uppervp, |
| 468 | (uppervp ? uppervp->v_sysref.refcnt : -99) |
| 469 | )); |
| 470 | |
| 471 | if (uppervp != un->un_uppervp) { |
| 472 | KASSERT(uppervp == NULL || uppervp->v_sysref.refcnt > 0, ("union_allocvp: too few refs %d (at least 1 required) on uppervp", uppervp->v_sysref.refcnt)); |
| 473 | union_newupper(un, uppervp); |
| 474 | } else if (uppervp) { |
| 475 | KASSERT(uppervp->v_sysref.refcnt > 1, ("union_allocvp: too few refs %d (at least 2 required) on uppervp", uppervp->v_sysref.refcnt)); |
| 476 | vrele(uppervp); |
| 477 | } |
| 478 | |
| 479 | /* |
| 480 | * Save information about the lower layer. |
| 481 | * This needs to keep track of pathname |
| 482 | * and directory information which union_vn_create |
| 483 | * might need. |
| 484 | */ |
| 485 | if (lowervp != un->un_lowervp) { |
| 486 | union_newlower(un, lowervp); |
| 487 | if (cnp && (lowervp != NULLVP)) { |
| 488 | un->un_path = malloc(cnp->cn_namelen+1, |
| 489 | M_TEMP, M_WAITOK); |
| 490 | bcopy(cnp->cn_nameptr, un->un_path, |
| 491 | cnp->cn_namelen); |
| 492 | un->un_path[cnp->cn_namelen] = '\0'; |
| 493 | } |
| 494 | } else if (lowervp) { |
| 495 | vrele(lowervp); |
| 496 | } |
| 497 | |
| 498 | /* |
| 499 | * and upperdvp |
| 500 | */ |
| 501 | if (upperdvp != un->un_dirvp) { |
| 502 | if (un->un_dirvp) |
| 503 | vrele(un->un_dirvp); |
| 504 | un->un_dirvp = upperdvp; |
| 505 | } else if (upperdvp) { |
| 506 | vrele(upperdvp); |
| 507 | } |
| 508 | |
| 509 | *vpp = UNIONTOV(un); |
| 510 | return (0); |
| 511 | } |
| 512 | |
| 513 | if (docache) { |
| 514 | /* |
| 515 | * otherwise lock the vp list while we call getnewvnode |
| 516 | * since that can block. |
| 517 | */ |
| 518 | hash = UNION_HASH(uppervp, lowervp); |
| 519 | |
| 520 | if (union_list_lock(hash)) |
| 521 | goto loop; |
| 522 | } |
| 523 | |
| 524 | /* |
| 525 | * Create new node rather then replace old node |
| 526 | */ |
| 527 | |
| 528 | error = getnewvnode(VT_UNION, mp, vpp, 0, 0); |
| 529 | if (error) { |
| 530 | /* |
| 531 | * If an error occurs clear out vnodes. |
| 532 | */ |
| 533 | if (lowervp) |
| 534 | vrele(lowervp); |
| 535 | if (uppervp) |
| 536 | vrele(uppervp); |
| 537 | if (upperdvp) |
| 538 | vrele(upperdvp); |
| 539 | *vpp = NULL; |
| 540 | goto out; |
| 541 | } |
| 542 | |
| 543 | (*vpp)->v_data = kmalloc(sizeof(struct union_node), M_TEMP, M_WAITOK); |
| 544 | |
| 545 | vsetflags(*vpp, vflag); |
| 546 | if (uppervp) |
| 547 | (*vpp)->v_type = uppervp->v_type; |
| 548 | else |
| 549 | (*vpp)->v_type = lowervp->v_type; |
| 550 | |
| 551 | un = VTOUNION(*vpp); |
| 552 | bzero(un, sizeof(*un)); |
| 553 | |
| 554 | un->un_vnode = *vpp; |
| 555 | un->un_uppervp = uppervp; |
| 556 | un->un_uppersz = VNOVAL; |
| 557 | un->un_lowervp = lowervp; |
| 558 | un->un_lowersz = VNOVAL; |
| 559 | un->un_dirvp = upperdvp; |
| 560 | un->un_pvp = dvp; /* only parent dir in new allocation */ |
| 561 | if (dvp != NULLVP) |
| 562 | vref(dvp); |
| 563 | un->un_dircache = 0; |
| 564 | un->un_openl = 0; |
| 565 | |
| 566 | if (cnp && (lowervp != NULLVP)) { |
| 567 | un->un_path = kmalloc(cnp->cn_namelen+1, M_TEMP, M_WAITOK); |
| 568 | bcopy(cnp->cn_nameptr, un->un_path, cnp->cn_namelen); |
| 569 | un->un_path[cnp->cn_namelen] = '\0'; |
| 570 | } else { |
| 571 | un->un_path = 0; |
| 572 | un->un_dirvp = NULL; |
| 573 | } |
| 574 | |
| 575 | if (docache) { |
| 576 | LIST_INSERT_HEAD(&unhead[hash], un, un_cache); |
| 577 | un->un_flags |= UN_CACHED; |
| 578 | } |
| 579 | |
| 580 | /* |
| 581 | * locked refd vpp is returned |
| 582 | */ |
| 583 | |
| 584 | out: |
| 585 | if (docache) |
| 586 | union_list_unlock(hash); |
| 587 | |
| 588 | return (error); |
| 589 | } |
| 590 | |
| 591 | int |
| 592 | union_freevp(struct vnode *vp) |
| 593 | { |
| 594 | struct union_node *un = VTOUNION(vp); |
| 595 | |
| 596 | vp->v_data = NULL; |
| 597 | if (un->un_flags & UN_CACHED) { |
| 598 | un->un_flags &= ~UN_CACHED; |
| 599 | LIST_REMOVE(un, un_cache); |
| 600 | } |
| 601 | if (un->un_pvp != NULLVP) { |
| 602 | vrele(un->un_pvp); |
| 603 | un->un_pvp = NULL; |
| 604 | } |
| 605 | if (un->un_uppervp != NULLVP) { |
| 606 | vrele(un->un_uppervp); |
| 607 | un->un_uppervp = NULL; |
| 608 | } |
| 609 | if (un->un_lowervp != NULLVP) { |
| 610 | vrele(un->un_lowervp); |
| 611 | un->un_lowervp = NULL; |
| 612 | } |
| 613 | if (un->un_dirvp != NULLVP) { |
| 614 | vrele(un->un_dirvp); |
| 615 | un->un_dirvp = NULL; |
| 616 | } |
| 617 | if (un->un_path) { |
| 618 | kfree(un->un_path, M_TEMP); |
| 619 | un->un_path = NULL; |
| 620 | } |
| 621 | kfree(un, M_TEMP); |
| 622 | return (0); |
| 623 | } |
| 624 | |
| 625 | /* |
| 626 | * copyfile. copy the vnode (fvp) to the vnode (tvp) |
| 627 | * using a sequence of reads and writes. both (fvp) |
| 628 | * and (tvp) are locked on entry and exit. |
| 629 | * |
| 630 | * fvp and tvp are both exclusive locked on call, but their refcount's |
| 631 | * haven't been bumped at all. |
| 632 | */ |
| 633 | static int |
| 634 | union_copyfile(struct vnode *fvp, struct vnode *tvp, struct ucred *cred, |
| 635 | struct thread *td) |
| 636 | { |
| 637 | char *buf; |
| 638 | struct uio uio; |
| 639 | struct iovec iov; |
| 640 | int error = 0; |
| 641 | |
| 642 | /* |
| 643 | * strategy: |
| 644 | * allocate a buffer of size MAXBSIZE. |
| 645 | * loop doing reads and writes, keeping track |
| 646 | * of the current uio offset. |
| 647 | * give up at the first sign of trouble. |
| 648 | */ |
| 649 | |
| 650 | bzero(&uio, sizeof(uio)); |
| 651 | |
| 652 | uio.uio_td = td; |
| 653 | uio.uio_segflg = UIO_SYSSPACE; |
| 654 | uio.uio_offset = 0; |
| 655 | |
| 656 | buf = kmalloc(MAXBSIZE, M_TEMP, M_WAITOK); |
| 657 | |
| 658 | /* ugly loop follows... */ |
| 659 | do { |
| 660 | off_t offset = uio.uio_offset; |
| 661 | int count; |
| 662 | int bufoffset; |
| 663 | |
| 664 | /* |
| 665 | * Setup for big read |
| 666 | */ |
| 667 | uio.uio_iov = &iov; |
| 668 | uio.uio_iovcnt = 1; |
| 669 | iov.iov_base = buf; |
| 670 | iov.iov_len = MAXBSIZE; |
| 671 | uio.uio_resid = iov.iov_len; |
| 672 | uio.uio_rw = UIO_READ; |
| 673 | |
| 674 | if ((error = VOP_READ(fvp, &uio, 0, cred)) != 0) |
| 675 | break; |
| 676 | |
| 677 | /* |
| 678 | * Get bytes read, handle read eof case and setup for |
| 679 | * write loop |
| 680 | */ |
| 681 | if ((count = MAXBSIZE - uio.uio_resid) == 0) |
| 682 | break; |
| 683 | bufoffset = 0; |
| 684 | |
| 685 | /* |
| 686 | * Write until an error occurs or our buffer has been |
| 687 | * exhausted, then update the offset for the next read. |
| 688 | */ |
| 689 | while (bufoffset < count) { |
| 690 | uio.uio_iov = &iov; |
| 691 | uio.uio_iovcnt = 1; |
| 692 | iov.iov_base = buf + bufoffset; |
| 693 | iov.iov_len = count - bufoffset; |
| 694 | uio.uio_offset = offset + bufoffset; |
| 695 | uio.uio_rw = UIO_WRITE; |
| 696 | uio.uio_resid = iov.iov_len; |
| 697 | |
| 698 | if ((error = VOP_WRITE(tvp, &uio, 0, cred)) != 0) |
| 699 | break; |
| 700 | bufoffset += (count - bufoffset) - uio.uio_resid; |
| 701 | } |
| 702 | uio.uio_offset = offset + bufoffset; |
| 703 | } while (error == 0); |
| 704 | |
| 705 | kfree(buf, M_TEMP); |
| 706 | return (error); |
| 707 | } |
| 708 | |
| 709 | /* |
| 710 | * |
| 711 | * un's vnode is assumed to be locked on entry and remains locked on exit. |
| 712 | */ |
| 713 | |
| 714 | int |
| 715 | union_copyup(struct union_node *un, int docopy, struct ucred *cred, |
| 716 | struct thread *td) |
| 717 | { |
| 718 | int error; |
| 719 | struct vnode *lvp, *uvp; |
| 720 | |
| 721 | /* |
| 722 | * If the user does not have read permission, the vnode should not |
| 723 | * be copied to upper layer. |
| 724 | */ |
| 725 | vn_lock(un->un_lowervp, LK_EXCLUSIVE | LK_RETRY); |
| 726 | error = VOP_EACCESS(un->un_lowervp, VREAD, cred); |
| 727 | vn_unlock(un->un_lowervp); |
| 728 | if (error) |
| 729 | return (error); |
| 730 | |
| 731 | error = union_vn_create(&uvp, un, td); |
| 732 | if (error) |
| 733 | return (error); |
| 734 | |
| 735 | lvp = un->un_lowervp; |
| 736 | |
| 737 | KASSERT(uvp->v_sysref.refcnt > 0, ("copy: uvp refcount 0: %d", uvp->v_sysref.refcnt)); |
| 738 | if (docopy) { |
| 739 | /* |
| 740 | * XX - should not ignore errors |
| 741 | * from VOP_CLOSE |
| 742 | */ |
| 743 | vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY); |
| 744 | error = VOP_OPEN(lvp, FREAD, cred, NULL); |
| 745 | if (error == 0) { |
| 746 | error = union_copyfile(lvp, uvp, cred, td); |
| 747 | vn_unlock(lvp); |
| 748 | (void) VOP_CLOSE(lvp, FREAD); |
| 749 | } |
| 750 | if (error == 0) |
| 751 | UDEBUG(("union: copied up %s\n", un->un_path)); |
| 752 | |
| 753 | } |
| 754 | vn_unlock(uvp); |
| 755 | union_newupper(un, uvp); |
| 756 | KASSERT(uvp->v_sysref.refcnt > 0, ("copy: uvp refcount 0: %d", uvp->v_sysref.refcnt)); |
| 757 | union_vn_close(uvp, FWRITE, cred); |
| 758 | KASSERT(uvp->v_sysref.refcnt > 0, ("copy: uvp refcount 0: %d", uvp->v_sysref.refcnt)); |
| 759 | /* |
| 760 | * Subsequent IOs will go to the top layer, so |
| 761 | * call close on the lower vnode and open on the |
| 762 | * upper vnode to ensure that the filesystem keeps |
| 763 | * its references counts right. This doesn't do |
| 764 | * the right thing with (cred) and (FREAD) though. |
| 765 | * Ignoring error returns is not right, either. |
| 766 | */ |
| 767 | if (error == 0) { |
| 768 | int i; |
| 769 | |
| 770 | for (i = 0; i < un->un_openl; i++) { |
| 771 | VOP_CLOSE(lvp, FREAD); |
| 772 | VOP_OPEN(uvp, FREAD, cred, NULL); |
| 773 | } |
| 774 | un->un_openl = 0; |
| 775 | } |
| 776 | |
| 777 | return (error); |
| 778 | |
| 779 | } |
| 780 | |
| 781 | /* |
| 782 | * union_relookup: |
| 783 | * |
| 784 | * dvp should be locked on entry and will be locked on return. No |
| 785 | * net change in the ref count will occur. |
| 786 | * |
| 787 | * If an error is returned, *vpp will be invalid, otherwise it |
| 788 | * will hold a locked, referenced vnode. If *vpp == dvp then |
| 789 | * remember that only one exclusive lock is held. |
| 790 | */ |
| 791 | |
| 792 | static int |
| 793 | union_relookup(struct union_mount *um, struct vnode *dvp, struct vnode **vpp, |
| 794 | struct componentname *cnp, struct componentname *cn, char *path, |
| 795 | int pathlen) |
| 796 | { |
| 797 | int error; |
| 798 | |
| 799 | /* |
| 800 | * A new componentname structure must be faked up because |
| 801 | * there is no way to know where the upper level cnp came |
| 802 | * from or what it is being used for. This must duplicate |
| 803 | * some of the work done by NDINIT, some of the work done |
| 804 | * by namei, some of the work done by lookup and some of |
| 805 | * the work done by VOP_LOOKUP when given a CREATE flag. |
| 806 | * Conclusion: Horrible. |
| 807 | */ |
| 808 | cn->cn_namelen = pathlen; |
| 809 | cn->cn_nameptr = objcache_get(namei_oc, M_WAITOK); |
| 810 | bcopy(path, cn->cn_nameptr, cn->cn_namelen); |
| 811 | cn->cn_nameptr[cn->cn_namelen] = '\0'; |
| 812 | |
| 813 | cn->cn_nameiop = NAMEI_CREATE; |
| 814 | cn->cn_flags = CNP_LOCKPARENT; |
| 815 | cn->cn_td = cnp->cn_td; |
| 816 | if (um->um_op == UNMNT_ABOVE) |
| 817 | cn->cn_cred = cnp->cn_cred; |
| 818 | else |
| 819 | cn->cn_cred = um->um_cred; |
| 820 | cn->cn_consume = cnp->cn_consume; |
| 821 | |
| 822 | vref(dvp); |
| 823 | vn_unlock(dvp); |
| 824 | |
| 825 | /* |
| 826 | * Pass dvp unlocked and referenced on call to relookup(). |
| 827 | * |
| 828 | * If an error occurs, dvp will be returned unlocked and dereferenced. |
| 829 | */ |
| 830 | |
| 831 | if ((error = relookup(dvp, vpp, cn)) != 0) { |
| 832 | objcache_put(namei_oc, cn->cn_nameptr); |
| 833 | vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); |
| 834 | return(error); |
| 835 | } |
| 836 | objcache_put(namei_oc, cn->cn_nameptr); |
| 837 | |
| 838 | /* |
| 839 | * If no error occurs, dvp will be returned locked with the reference |
| 840 | * left as before, and vpp will be returned referenced and locked. |
| 841 | * |
| 842 | * We want to return with dvp as it was passed to us, so we get |
| 843 | * rid of our reference. |
| 844 | */ |
| 845 | vrele(dvp); |
| 846 | return (0); |
| 847 | } |
| 848 | |
| 849 | /* |
| 850 | * Create a shadow directory in the upper layer. |
| 851 | * The new vnode is returned locked. |
| 852 | * |
| 853 | * (um) points to the union mount structure for access to the |
| 854 | * the mounting process's credentials. |
| 855 | * (dvp) is the directory in which to create the shadow directory, |
| 856 | * it is locked (but not ref'd) on entry and return. |
| 857 | * (cnp) is the componentname to be created. |
| 858 | * (vpp) is the returned newly created shadow directory, which |
| 859 | * is returned locked and ref'd |
| 860 | */ |
| 861 | int |
| 862 | union_mkshadow(struct union_mount *um, struct vnode *dvp, |
| 863 | struct componentname *cnp, struct vnode **vpp) |
| 864 | { |
| 865 | int error; |
| 866 | struct vattr va; |
| 867 | struct thread *td = cnp->cn_td; |
| 868 | struct componentname cn; |
| 869 | |
| 870 | error = union_relookup(um, dvp, vpp, cnp, &cn, |
| 871 | cnp->cn_nameptr, cnp->cn_namelen); |
| 872 | if (error) |
| 873 | return (error); |
| 874 | |
| 875 | if (*vpp) { |
| 876 | if (dvp == *vpp) |
| 877 | vrele(*vpp); |
| 878 | else |
| 879 | vput(*vpp); |
| 880 | *vpp = NULLVP; |
| 881 | return (EEXIST); |
| 882 | } |
| 883 | |
| 884 | /* |
| 885 | * policy: when creating the shadow directory in the |
| 886 | * upper layer, create it owned by the user who did |
| 887 | * the mount, group from parent directory, and mode |
| 888 | * 777 modified by umask (ie mostly identical to the |
| 889 | * mkdir syscall). (jsp, kb) |
| 890 | */ |
| 891 | |
| 892 | VATTR_NULL(&va); |
| 893 | va.va_type = VDIR; |
| 894 | va.va_mode = um->um_cmode; |
| 895 | |
| 896 | error = VOP_MKDIR(dvp, vpp, &cn, &va); |
| 897 | /*vput(dvp);*/ |
| 898 | return (error); |
| 899 | } |
| 900 | |
| 901 | /* |
| 902 | * Create a whiteout entry in the upper layer. |
| 903 | * |
| 904 | * (um) points to the union mount structure for access to the |
| 905 | * the mounting process's credentials. |
| 906 | * (dvp) is the directory in which to create the whiteout. |
| 907 | * it is locked on entry and return. |
| 908 | * (cnp) is the componentname to be created. |
| 909 | */ |
| 910 | int |
| 911 | union_mkwhiteout(struct union_mount *um, struct vnode *dvp, |
| 912 | struct componentname *cnp, char *path) |
| 913 | { |
| 914 | int error; |
| 915 | struct thread *td = cnp->cn_td; |
| 916 | struct vnode *wvp; |
| 917 | struct componentname cn; |
| 918 | |
| 919 | KKASSERT(td->td_proc); |
| 920 | |
| 921 | error = union_relookup(um, dvp, &wvp, cnp, &cn, path, strlen(path)); |
| 922 | if (error) |
| 923 | return (error); |
| 924 | |
| 925 | if (wvp) { |
| 926 | if (wvp == dvp) |
| 927 | vrele(wvp); |
| 928 | else |
| 929 | vput(wvp); |
| 930 | return (EEXIST); |
| 931 | } |
| 932 | |
| 933 | error = VOP_WHITEOUT(dvp, &cn, NAMEI_CREATE); |
| 934 | return (error); |
| 935 | } |
| 936 | |
| 937 | /* |
| 938 | * union_vn_create: creates and opens a new shadow file |
| 939 | * on the upper union layer. this function is similar |
| 940 | * in spirit to calling vn_open but it avoids calling namei(). |
| 941 | * the problem with calling namei is that a) it locks too many |
| 942 | * things, and b) it doesn't start at the "right" directory, |
| 943 | * whereas relookup is told where to start. |
| 944 | * |
| 945 | * On entry, the vnode associated with un is locked. It remains locked |
| 946 | * on return. |
| 947 | * |
| 948 | * If no error occurs, *vpp contains a locked referenced vnode for your |
| 949 | * use. If an error occurs *vpp iis undefined. |
| 950 | */ |
| 951 | static int |
| 952 | union_vn_create(struct vnode **vpp, struct union_node *un, struct thread *td) |
| 953 | { |
| 954 | struct vnode *vp; |
| 955 | struct ucred *cred; |
| 956 | struct vattr vat; |
| 957 | struct vattr *vap = &vat; |
| 958 | int fmode = FFLAGS(O_WRONLY|O_CREAT|O_TRUNC|O_EXCL); |
| 959 | int error; |
| 960 | int cmode; |
| 961 | struct componentname cn; |
| 962 | |
| 963 | KKASSERT(td->td_proc); |
| 964 | cred = td->td_proc->p_ucred; |
| 965 | cmode = UN_FILEMODE & ~td->td_proc->p_fd->fd_cmask; |
| 966 | |
| 967 | *vpp = NULLVP; |
| 968 | |
| 969 | /* |
| 970 | * Build a new componentname structure (for the same |
| 971 | * reasons outlines in union_mkshadow). |
| 972 | * The difference here is that the file is owned by |
| 973 | * the current user, rather than by the person who |
| 974 | * did the mount, since the current user needs to be |
| 975 | * able to write the file (that's why it is being |
| 976 | * copied in the first place). |
| 977 | */ |
| 978 | cn.cn_namelen = strlen(un->un_path); |
| 979 | cn.cn_nameptr = objcache_get(namei_oc, M_WAITOK); |
| 980 | bcopy(un->un_path, cn.cn_nameptr, cn.cn_namelen+1); |
| 981 | cn.cn_nameiop = NAMEI_CREATE; |
| 982 | cn.cn_flags = CNP_LOCKPARENT; |
| 983 | cn.cn_td = td; |
| 984 | cn.cn_cred = cred; |
| 985 | cn.cn_consume = 0; |
| 986 | |
| 987 | /* |
| 988 | * Pass dvp unlocked and referenced on call to relookup(). |
| 989 | * |
| 990 | * If an error occurs, dvp will be returned unlocked and dereferenced. |
| 991 | */ |
| 992 | vref(un->un_dirvp); |
| 993 | error = relookup(un->un_dirvp, &vp, &cn); |
| 994 | objcache_put(namei_oc, cn.cn_nameptr); |
| 995 | if (error) |
| 996 | return (error); |
| 997 | |
| 998 | /* |
| 999 | * If no error occurs, dvp will be returned locked with the reference |
| 1000 | * left as before, and vpp will be returned referenced and locked. |
| 1001 | */ |
| 1002 | if (vp) { |
| 1003 | vput(un->un_dirvp); |
| 1004 | if (vp == un->un_dirvp) |
| 1005 | vrele(vp); |
| 1006 | else |
| 1007 | vput(vp); |
| 1008 | return (EEXIST); |
| 1009 | } |
| 1010 | |
| 1011 | /* |
| 1012 | * Good - there was no race to create the file |
| 1013 | * so go ahead and create it. The permissions |
| 1014 | * on the file will be 0666 modified by the |
| 1015 | * current user's umask. Access to the file, while |
| 1016 | * it is unioned, will require access to the top *and* |
| 1017 | * bottom files. Access when not unioned will simply |
| 1018 | * require access to the top-level file. |
| 1019 | * TODO: confirm choice of access permissions. |
| 1020 | */ |
| 1021 | VATTR_NULL(vap); |
| 1022 | vap->va_type = VREG; |
| 1023 | vap->va_mode = cmode; |
| 1024 | error = VOP_CREATE(un->un_dirvp, &vp, &cn, vap); |
| 1025 | vput(un->un_dirvp); |
| 1026 | if (error) |
| 1027 | return (error); |
| 1028 | |
| 1029 | error = VOP_OPEN(vp, fmode, cred, NULL); |
| 1030 | if (error) { |
| 1031 | vput(vp); |
| 1032 | return (error); |
| 1033 | } |
| 1034 | *vpp = vp; |
| 1035 | return (0); |
| 1036 | } |
| 1037 | |
| 1038 | static int |
| 1039 | union_vn_close(struct vnode *vp, int fmode, struct ucred *cred) |
| 1040 | { |
| 1041 | return (VOP_CLOSE(vp, fmode)); |
| 1042 | } |
| 1043 | |
| 1044 | #if 0 |
| 1045 | |
| 1046 | /* |
| 1047 | * union_removed_upper: |
| 1048 | * |
| 1049 | * called with union_node unlocked. XXX |
| 1050 | */ |
| 1051 | |
| 1052 | void |
| 1053 | union_removed_upper(struct union_node *un) |
| 1054 | { |
| 1055 | struct thread *td = curthread; /* XXX */ |
| 1056 | struct vnode **vpp; |
| 1057 | |
| 1058 | /* |
| 1059 | * Do not set the uppervp to NULLVP. If lowervp is NULLVP, |
| 1060 | * union node will have neither uppervp nor lowervp. We remove |
| 1061 | * the union node from cache, so that it will not be referrenced. |
| 1062 | */ |
| 1063 | union_newupper(un, NULLVP); |
| 1064 | if (un->un_dircache != 0) { |
| 1065 | for (vpp = un->un_dircache; *vpp != NULLVP; vpp++) |
| 1066 | vrele(*vpp); |
| 1067 | kfree(un->un_dircache, M_TEMP); |
| 1068 | un->un_dircache = 0; |
| 1069 | } |
| 1070 | |
| 1071 | if (un->un_flags & UN_CACHED) { |
| 1072 | un->un_flags &= ~UN_CACHED; |
| 1073 | LIST_REMOVE(un, un_cache); |
| 1074 | } |
| 1075 | } |
| 1076 | |
| 1077 | #endif |
| 1078 | |
| 1079 | /* |
| 1080 | * determine whether a whiteout is needed |
| 1081 | * during a remove/rmdir operation. |
| 1082 | */ |
| 1083 | int |
| 1084 | union_dowhiteout(struct union_node *un, struct ucred *cred, struct thread *td) |
| 1085 | { |
| 1086 | struct vattr va; |
| 1087 | |
| 1088 | if (un->un_lowervp != NULLVP) |
| 1089 | return (1); |
| 1090 | |
| 1091 | if (VOP_GETATTR(un->un_uppervp, &va) == 0 && |
| 1092 | (va.va_flags & OPAQUE)) |
| 1093 | return (1); |
| 1094 | |
| 1095 | return (0); |
| 1096 | } |
| 1097 | |
| 1098 | static void |
| 1099 | union_dircache_r(struct vnode *vp, struct vnode ***vppp, int *cntp) |
| 1100 | { |
| 1101 | struct union_node *un; |
| 1102 | |
| 1103 | if (vp->v_tag != VT_UNION) { |
| 1104 | if (vppp) { |
| 1105 | vref(vp); |
| 1106 | *(*vppp)++ = vp; |
| 1107 | if (--(*cntp) == 0) |
| 1108 | panic("union: dircache table too small"); |
| 1109 | } else { |
| 1110 | (*cntp)++; |
| 1111 | } |
| 1112 | |
| 1113 | return; |
| 1114 | } |
| 1115 | |
| 1116 | un = VTOUNION(vp); |
| 1117 | if (un->un_uppervp != NULLVP) |
| 1118 | union_dircache_r(un->un_uppervp, vppp, cntp); |
| 1119 | if (un->un_lowervp != NULLVP) |
| 1120 | union_dircache_r(un->un_lowervp, vppp, cntp); |
| 1121 | } |
| 1122 | |
| 1123 | struct vnode * |
| 1124 | union_dircache(struct vnode *vp, struct thread *td) |
| 1125 | { |
| 1126 | int cnt; |
| 1127 | struct vnode *nvp; |
| 1128 | struct vnode **vpp; |
| 1129 | struct vnode **dircache; |
| 1130 | struct union_node *un; |
| 1131 | int error; |
| 1132 | |
| 1133 | vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); |
| 1134 | dircache = VTOUNION(vp)->un_dircache; |
| 1135 | |
| 1136 | nvp = NULLVP; |
| 1137 | |
| 1138 | if (dircache == NULL) { |
| 1139 | cnt = 0; |
| 1140 | union_dircache_r(vp, 0, &cnt); |
| 1141 | cnt++; |
| 1142 | dircache = malloc(cnt * sizeof(struct vnode *), |
| 1143 | M_TEMP, M_WAITOK); |
| 1144 | vpp = dircache; |
| 1145 | union_dircache_r(vp, &vpp, &cnt); |
| 1146 | *vpp = NULLVP; |
| 1147 | vpp = dircache + 1; |
| 1148 | } else { |
| 1149 | vpp = dircache; |
| 1150 | do { |
| 1151 | if (*vpp++ == VTOUNION(vp)->un_uppervp) |
| 1152 | break; |
| 1153 | } while (*vpp != NULLVP); |
| 1154 | } |
| 1155 | |
| 1156 | if (*vpp == NULLVP) |
| 1157 | goto out; |
| 1158 | |
| 1159 | /*vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);*/ |
| 1160 | UDEBUG(("ALLOCVP-3 %p ref %d\n", *vpp, (*vpp ? (*vpp)->v_sysref.refcnt : -99))); |
| 1161 | vref(*vpp); |
| 1162 | error = union_allocvp(&nvp, vp->v_mount, NULLVP, NULLVP, NULL, *vpp, NULLVP, 0); |
| 1163 | UDEBUG(("ALLOCVP-3B %p ref %d\n", nvp, (*vpp ? (*vpp)->v_sysref.refcnt : -99))); |
| 1164 | if (error) |
| 1165 | goto out; |
| 1166 | |
| 1167 | VTOUNION(vp)->un_dircache = 0; |
| 1168 | un = VTOUNION(nvp); |
| 1169 | un->un_dircache = dircache; |
| 1170 | |
| 1171 | out: |
| 1172 | vn_unlock(vp); |
| 1173 | return (nvp); |
| 1174 | } |
| 1175 | |
| 1176 | /* |
| 1177 | * Guarentee coherency with the VM cache by invalidating any clean VM pages |
| 1178 | * associated with this write and updating any dirty VM pages. Since our |
| 1179 | * vnode is locked, other processes will not be able to read the pages in |
| 1180 | * again until after our write completes. |
| 1181 | * |
| 1182 | * We also have to be coherent with reads, by flushing any pending dirty |
| 1183 | * pages prior to issuing the read. |
| 1184 | * |
| 1185 | * XXX this is somewhat of a hack at the moment. To support this properly |
| 1186 | * we would have to be able to run VOP_READ and VOP_WRITE through the VM |
| 1187 | * cache. Then we wouldn't need to worry about coherency. |
| 1188 | */ |
| 1189 | |
| 1190 | void |
| 1191 | union_vm_coherency(struct vnode *vp, struct uio *uio, int cleanfls) |
| 1192 | { |
| 1193 | vm_object_t object; |
| 1194 | vm_pindex_t pstart; |
| 1195 | vm_pindex_t pend; |
| 1196 | int pgoff; |
| 1197 | |
| 1198 | if ((object = vp->v_object) == NULL) |
| 1199 | return; |
| 1200 | |
| 1201 | pgoff = uio->uio_offset & PAGE_MASK; |
| 1202 | pstart = uio->uio_offset / PAGE_SIZE; |
| 1203 | pend = pstart + (uio->uio_resid + pgoff + PAGE_MASK) / PAGE_SIZE; |
| 1204 | |
| 1205 | vm_object_page_clean(object, pstart, pend, OBJPC_SYNC); |
| 1206 | if (cleanfls) |
| 1207 | vm_object_page_remove(object, pstart, pend, TRUE); |
| 1208 | } |
| 1209 | |
| 1210 | /* |
| 1211 | * Module glue to remove #ifdef UNION from vfs_syscalls.c |
| 1212 | */ |
| 1213 | static int |
| 1214 | union_dircheck(struct thread *td, struct vnode **vp, struct file *fp) |
| 1215 | { |
| 1216 | int error = 0; |
| 1217 | |
| 1218 | if ((*vp)->v_tag == VT_UNION) { |
| 1219 | struct vnode *lvp; |
| 1220 | |
| 1221 | lvp = union_dircache(*vp, td); |
| 1222 | if (lvp != NULLVP) { |
| 1223 | struct vattr va; |
| 1224 | |
| 1225 | /* |
| 1226 | * If the directory is opaque, |
| 1227 | * then don't show lower entries |
| 1228 | */ |
| 1229 | error = VOP_GETATTR(*vp, &va); |
| 1230 | if (va.va_flags & OPAQUE) { |
| 1231 | vput(lvp); |
| 1232 | lvp = NULL; |
| 1233 | } |
| 1234 | } |
| 1235 | |
| 1236 | if (lvp != NULLVP) { |
| 1237 | error = VOP_OPEN(lvp, FREAD, fp->f_cred, NULL); |
| 1238 | if (error) { |
| 1239 | vput(lvp); |
| 1240 | return (error); |
| 1241 | } |
| 1242 | vn_unlock(lvp); |
| 1243 | fp->f_data = lvp; |
| 1244 | fp->f_offset = 0; |
| 1245 | error = vn_close(*vp, FREAD); |
| 1246 | if (error) |
| 1247 | return (error); |
| 1248 | *vp = lvp; |
| 1249 | return -1; /* goto unionread */ |
| 1250 | } |
| 1251 | } |
| 1252 | return error; |
| 1253 | } |
| 1254 | |
| 1255 | static int |
| 1256 | union_modevent(module_t mod, int type, void *data) |
| 1257 | { |
| 1258 | switch (type) { |
| 1259 | case MOD_LOAD: |
| 1260 | union_dircheckp = union_dircheck; |
| 1261 | break; |
| 1262 | case MOD_UNLOAD: |
| 1263 | union_dircheckp = NULL; |
| 1264 | break; |
| 1265 | default: |
| 1266 | break; |
| 1267 | } |
| 1268 | return 0; |
| 1269 | } |
| 1270 | |
| 1271 | static moduledata_t union_mod = { |
| 1272 | "union_dircheck", |
| 1273 | union_modevent, |
| 1274 | NULL |
| 1275 | }; |
| 1276 | |
| 1277 | DECLARE_MODULE(union_dircheck, union_mod, SI_SUB_VFS, SI_ORDER_ANY); |