1 /*- 2 * modified for Lites 1.1 3 * 4 * Aug 1995, Godmar Back (gback@cs.utah.edu) 5 * University of Utah, Department of Computer Science 6 */ 7 /*- 8 * SPDX-License-Identifier: BSD-3-Clause 9 * 10 * Copyright (c) 1982, 1986, 1989, 1993 11 * The Regents of the University of California. All rights reserved. 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 * @(#)ffs_inode.c 8.5 (Berkeley) 12/30/93 38 * $FreeBSD$ 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/mount.h> 44 #include <sys/bio.h> 45 #include <sys/buf.h> 46 #include <sys/vnode.h> 47 #include <sys/malloc.h> 48 #include <sys/rwlock.h> 49 #include <sys/sdt.h> 50 51 #include <vm/vm.h> 52 #include <vm/vm_extern.h> 53 54 #include <fs/ext2fs/fs.h> 55 #include <fs/ext2fs/inode.h> 56 #include <fs/ext2fs/ext2_mount.h> 57 #include <fs/ext2fs/ext2fs.h> 58 #include <fs/ext2fs/fs.h> 59 #include <fs/ext2fs/ext2_extern.h> 60 #include <fs/ext2fs/ext2_extattr.h> 61 62 /* 63 * Update the access, modified, and inode change times as specified by the 64 * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively. Write the inode 65 * to disk if the IN_MODIFIED flag is set (it may be set initially, or by 66 * the timestamp update). The IN_LAZYMOD flag is set to force a write 67 * later if not now. If we write now, then clear both IN_MODIFIED and 68 * IN_LAZYMOD to reflect the presumably successful write, and if waitfor is 69 * set, then wait for the write to complete. 70 */ 71 int 72 ext2_update(struct vnode *vp, int waitfor) 73 { 74 struct m_ext2fs *fs; 75 struct buf *bp; 76 struct inode *ip; 77 int error; 78 79 ASSERT_VOP_ELOCKED(vp, "ext2_update"); 80 ext2_itimes(vp); 81 ip = VTOI(vp); 82 if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor == 0) 83 return (0); 84 ip->i_flag &= ~(IN_LAZYACCESS | IN_LAZYMOD | IN_MODIFIED); 85 fs = ip->i_e2fs; 86 if (fs->e2fs_ronly) 87 return (0); 88 if ((error = bread(ip->i_devvp, 89 fsbtodb(fs, ino_to_fsba(fs, ip->i_number)), 90 (int)fs->e2fs_bsize, NOCRED, &bp)) != 0) { 91 brelse(bp); 92 return (error); 93 } 94 error = ext2_i2ei(ip, (struct ext2fs_dinode *)((char *)bp->b_data + 95 EXT2_INODE_SIZE(fs) * ino_to_fsbo(fs, ip->i_number))); 96 if (error) { 97 brelse(bp); 98 return (error); 99 } 100 if (waitfor && !DOINGASYNC(vp)) 101 return (bwrite(bp)); 102 else { 103 bdwrite(bp); 104 return (0); 105 } 106 } 107 108 #define SINGLE 0 /* index of single indirect block */ 109 #define DOUBLE 1 /* index of double indirect block */ 110 #define TRIPLE 2 /* index of triple indirect block */ 111 112 /* 113 * Release blocks associated with the inode ip and stored in the indirect 114 * block bn. Blocks are free'd in LIFO order up to (but not including) 115 * lastbn. If level is greater than SINGLE, the block is an indirect block 116 * and recursive calls to indirtrunc must be used to cleanse other indirect 117 * blocks. 118 * 119 * NB: triple indirect blocks are untested. 120 */ 121 static int 122 ext2_indirtrunc(struct inode *ip, daddr_t lbn, daddr_t dbn, 123 daddr_t lastbn, int level, e4fs_daddr_t *countp) 124 { 125 struct buf *bp; 126 struct m_ext2fs *fs = ip->i_e2fs; 127 struct vnode *vp; 128 e2fs_daddr_t *bap, *copy; 129 int i, nblocks, error = 0, allerror = 0; 130 e2fs_lbn_t nb, nlbn, last; 131 e4fs_daddr_t blkcount, factor, blocksreleased = 0; 132 133 /* 134 * Calculate index in current block of last 135 * block to be kept. -1 indicates the entire 136 * block so we need not calculate the index. 137 */ 138 factor = 1; 139 for (i = SINGLE; i < level; i++) 140 factor *= NINDIR(fs); 141 last = lastbn; 142 if (lastbn > 0) 143 last /= factor; 144 nblocks = btodb(fs->e2fs_bsize); 145 /* 146 * Get buffer of block pointers, zero those entries corresponding 147 * to blocks to be free'd, and update on disk copy first. Since 148 * double(triple) indirect before single(double) indirect, calls 149 * to bmap on these blocks will fail. However, we already have 150 * the on disk address, so we have to set the b_blkno field 151 * explicitly instead of letting bread do everything for us. 152 */ 153 vp = ITOV(ip); 154 bp = getblk(vp, lbn, (int)fs->e2fs_bsize, 0, 0, 0); 155 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0) { 156 bp->b_iocmd = BIO_READ; 157 if (bp->b_bcount > bp->b_bufsize) 158 panic("ext2_indirtrunc: bad buffer size"); 159 bp->b_blkno = dbn; 160 vfs_busy_pages(bp, 0); 161 bp->b_iooffset = dbtob(bp->b_blkno); 162 bstrategy(bp); 163 error = bufwait(bp); 164 } 165 if (error) { 166 brelse(bp); 167 *countp = 0; 168 return (error); 169 } 170 bap = (e2fs_daddr_t *)bp->b_data; 171 copy = malloc(fs->e2fs_bsize, M_TEMP, M_WAITOK); 172 bcopy((caddr_t)bap, (caddr_t)copy, (u_int)fs->e2fs_bsize); 173 bzero((caddr_t)&bap[last + 1], 174 (NINDIR(fs) - (last + 1)) * sizeof(e2fs_daddr_t)); 175 if (last == -1) 176 bp->b_flags |= B_INVAL; 177 if (DOINGASYNC(vp)) { 178 bdwrite(bp); 179 } else { 180 error = bwrite(bp); 181 if (error) 182 allerror = error; 183 } 184 bap = copy; 185 186 /* 187 * Recursively free totally unused blocks. 188 */ 189 for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last; 190 i--, nlbn += factor) { 191 nb = bap[i]; 192 if (nb == 0) 193 continue; 194 if (level > SINGLE) { 195 if ((error = ext2_indirtrunc(ip, nlbn, 196 fsbtodb(fs, nb), (int32_t)-1, level - 1, &blkcount)) != 0) 197 allerror = error; 198 blocksreleased += blkcount; 199 } 200 ext2_blkfree(ip, nb, fs->e2fs_bsize); 201 blocksreleased += nblocks; 202 } 203 204 /* 205 * Recursively free last partial block. 206 */ 207 if (level > SINGLE && lastbn >= 0) { 208 last = lastbn % factor; 209 nb = bap[i]; 210 if (nb != 0) { 211 if ((error = ext2_indirtrunc(ip, nlbn, fsbtodb(fs, nb), 212 last, level - 1, &blkcount)) != 0) 213 allerror = error; 214 blocksreleased += blkcount; 215 } 216 } 217 free(copy, M_TEMP); 218 *countp = blocksreleased; 219 return (allerror); 220 } 221 222 /* 223 * Truncate the inode oip to at most length size, freeing the 224 * disk blocks. 225 */ 226 static int 227 ext2_ind_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred, 228 struct thread *td) 229 { 230 struct vnode *ovp = vp; 231 e4fs_daddr_t lastblock; 232 struct inode *oip; 233 e4fs_daddr_t bn, lbn, lastiblock[EXT2_NIADDR], indir_lbn[EXT2_NIADDR]; 234 uint32_t oldblks[EXT2_NDADDR + EXT2_NIADDR]; 235 uint32_t newblks[EXT2_NDADDR + EXT2_NIADDR]; 236 struct m_ext2fs *fs; 237 struct buf *bp; 238 int offset, size, level; 239 e4fs_daddr_t count, nblocks, blocksreleased = 0; 240 int error, i, allerror; 241 off_t osize; 242 #ifdef INVARIANTS 243 struct bufobj *bo; 244 #endif 245 246 oip = VTOI(ovp); 247 #ifdef INVARIANTS 248 bo = &ovp->v_bufobj; 249 #endif 250 251 fs = oip->i_e2fs; 252 osize = oip->i_size; 253 /* 254 * Lengthen the size of the file. We must ensure that the 255 * last byte of the file is allocated. Since the smallest 256 * value of osize is 0, length will be at least 1. 257 */ 258 if (osize < length) { 259 if (length > oip->i_e2fs->e2fs_maxfilesize) 260 return (EFBIG); 261 vnode_pager_setsize(ovp, length); 262 offset = blkoff(fs, length - 1); 263 lbn = lblkno(fs, length - 1); 264 flags |= BA_CLRBUF; 265 error = ext2_balloc(oip, lbn, offset + 1, cred, &bp, flags); 266 if (error) { 267 vnode_pager_setsize(vp, osize); 268 return (error); 269 } 270 oip->i_size = length; 271 if (bp->b_bufsize == fs->e2fs_bsize) 272 bp->b_flags |= B_CLUSTEROK; 273 if (flags & IO_SYNC) 274 bwrite(bp); 275 else if (DOINGASYNC(ovp)) 276 bdwrite(bp); 277 else 278 bawrite(bp); 279 oip->i_flag |= IN_CHANGE | IN_UPDATE; 280 return (ext2_update(ovp, !DOINGASYNC(ovp))); 281 } 282 /* 283 * Shorten the size of the file. If the file is not being 284 * truncated to a block boundary, the contents of the 285 * partial block following the end of the file must be 286 * zero'ed in case it ever become accessible again because 287 * of subsequent file growth. 288 */ 289 /* I don't understand the comment above */ 290 offset = blkoff(fs, length); 291 if (offset == 0) { 292 oip->i_size = length; 293 } else { 294 lbn = lblkno(fs, length); 295 flags |= BA_CLRBUF; 296 error = ext2_balloc(oip, lbn, offset, cred, &bp, flags); 297 if (error) 298 return (error); 299 oip->i_size = length; 300 size = blksize(fs, oip, lbn); 301 bzero((char *)bp->b_data + offset, (u_int)(size - offset)); 302 allocbuf(bp, size); 303 if (bp->b_bufsize == fs->e2fs_bsize) 304 bp->b_flags |= B_CLUSTEROK; 305 if (flags & IO_SYNC) 306 bwrite(bp); 307 else if (DOINGASYNC(ovp)) 308 bdwrite(bp); 309 else 310 bawrite(bp); 311 } 312 /* 313 * Calculate index into inode's block list of 314 * last direct and indirect blocks (if any) 315 * which we want to keep. Lastblock is -1 when 316 * the file is truncated to 0. 317 */ 318 lastblock = lblkno(fs, length + fs->e2fs_bsize - 1) - 1; 319 lastiblock[SINGLE] = lastblock - EXT2_NDADDR; 320 lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs); 321 lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs); 322 nblocks = btodb(fs->e2fs_bsize); 323 /* 324 * Update file and block pointers on disk before we start freeing 325 * blocks. If we crash before free'ing blocks below, the blocks 326 * will be returned to the free list. lastiblock values are also 327 * normalized to -1 for calls to ext2_indirtrunc below. 328 */ 329 for (level = TRIPLE; level >= SINGLE; level--) { 330 oldblks[EXT2_NDADDR + level] = oip->i_ib[level]; 331 if (lastiblock[level] < 0) { 332 oip->i_ib[level] = 0; 333 lastiblock[level] = -1; 334 } 335 } 336 for (i = 0; i < EXT2_NDADDR; i++) { 337 oldblks[i] = oip->i_db[i]; 338 if (i > lastblock) 339 oip->i_db[i] = 0; 340 } 341 oip->i_flag |= IN_CHANGE | IN_UPDATE; 342 allerror = ext2_update(ovp, !DOINGASYNC(ovp)); 343 344 /* 345 * Having written the new inode to disk, save its new configuration 346 * and put back the old block pointers long enough to process them. 347 * Note that we save the new block configuration so we can check it 348 * when we are done. 349 */ 350 for (i = 0; i < EXT2_NDADDR; i++) { 351 newblks[i] = oip->i_db[i]; 352 oip->i_db[i] = oldblks[i]; 353 } 354 for (i = 0; i < EXT2_NIADDR; i++) { 355 newblks[EXT2_NDADDR + i] = oip->i_ib[i]; 356 oip->i_ib[i] = oldblks[EXT2_NDADDR + i]; 357 } 358 oip->i_size = osize; 359 error = vtruncbuf(ovp, length, (int)fs->e2fs_bsize); 360 if (error && (allerror == 0)) 361 allerror = error; 362 vnode_pager_setsize(ovp, length); 363 364 /* 365 * Indirect blocks first. 366 */ 367 indir_lbn[SINGLE] = -EXT2_NDADDR; 368 indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) - 1; 369 indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1; 370 for (level = TRIPLE; level >= SINGLE; level--) { 371 bn = oip->i_ib[level]; 372 if (bn != 0) { 373 error = ext2_indirtrunc(oip, indir_lbn[level], 374 fsbtodb(fs, bn), lastiblock[level], level, &count); 375 if (error) 376 allerror = error; 377 blocksreleased += count; 378 if (lastiblock[level] < 0) { 379 oip->i_ib[level] = 0; 380 ext2_blkfree(oip, bn, fs->e2fs_fsize); 381 blocksreleased += nblocks; 382 } 383 } 384 if (lastiblock[level] >= 0) 385 goto done; 386 } 387 388 /* 389 * All whole direct blocks or frags. 390 */ 391 for (i = EXT2_NDADDR - 1; i > lastblock; i--) { 392 long bsize; 393 394 bn = oip->i_db[i]; 395 if (bn == 0) 396 continue; 397 oip->i_db[i] = 0; 398 bsize = blksize(fs, oip, i); 399 ext2_blkfree(oip, bn, bsize); 400 blocksreleased += btodb(bsize); 401 } 402 if (lastblock < 0) 403 goto done; 404 405 /* 406 * Finally, look for a change in size of the 407 * last direct block; release any frags. 408 */ 409 bn = oip->i_db[lastblock]; 410 if (bn != 0) { 411 long oldspace, newspace; 412 413 /* 414 * Calculate amount of space we're giving 415 * back as old block size minus new block size. 416 */ 417 oldspace = blksize(fs, oip, lastblock); 418 oip->i_size = length; 419 newspace = blksize(fs, oip, lastblock); 420 if (newspace == 0) 421 panic("ext2_truncate: newspace"); 422 if (oldspace - newspace > 0) { 423 /* 424 * Block number of space to be free'd is 425 * the old block # plus the number of frags 426 * required for the storage we're keeping. 427 */ 428 bn += numfrags(fs, newspace); 429 ext2_blkfree(oip, bn, oldspace - newspace); 430 blocksreleased += btodb(oldspace - newspace); 431 } 432 } 433 done: 434 #ifdef INVARIANTS 435 for (level = SINGLE; level <= TRIPLE; level++) 436 if (newblks[EXT2_NDADDR + level] != oip->i_ib[level]) 437 panic("itrunc1"); 438 for (i = 0; i < EXT2_NDADDR; i++) 439 if (newblks[i] != oip->i_db[i]) 440 panic("itrunc2"); 441 BO_LOCK(bo); 442 if (length == 0 && (bo->bo_dirty.bv_cnt != 0 || 443 bo->bo_clean.bv_cnt != 0)) 444 panic("itrunc3"); 445 BO_UNLOCK(bo); 446 #endif /* INVARIANTS */ 447 /* 448 * Put back the real size. 449 */ 450 oip->i_size = length; 451 if (oip->i_blocks >= blocksreleased) 452 oip->i_blocks -= blocksreleased; 453 else /* sanity */ 454 oip->i_blocks = 0; 455 oip->i_flag |= IN_CHANGE; 456 vnode_pager_setsize(ovp, length); 457 return (allerror); 458 } 459 460 static int 461 ext2_ext_truncate(struct vnode *vp, off_t length, int flags, 462 struct ucred *cred, struct thread *td) 463 { 464 struct vnode *ovp = vp; 465 int32_t lastblock; 466 struct m_ext2fs *fs; 467 struct inode *oip; 468 struct buf *bp; 469 uint32_t lbn, offset; 470 int error, size; 471 off_t osize; 472 473 oip = VTOI(ovp); 474 fs = oip->i_e2fs; 475 osize = oip->i_size; 476 477 if (osize < length) { 478 if (length > oip->i_e2fs->e2fs_maxfilesize) { 479 return (EFBIG); 480 } 481 vnode_pager_setsize(ovp, length); 482 offset = blkoff(fs, length - 1); 483 lbn = lblkno(fs, length - 1); 484 flags |= BA_CLRBUF; 485 error = ext2_balloc(oip, lbn, offset + 1, cred, &bp, flags); 486 if (error) { 487 vnode_pager_setsize(vp, osize); 488 return (error); 489 } 490 oip->i_size = length; 491 if (bp->b_bufsize == fs->e2fs_bsize) 492 bp->b_flags |= B_CLUSTEROK; 493 if (flags & IO_SYNC) 494 bwrite(bp); 495 else if (DOINGASYNC(ovp)) 496 bdwrite(bp); 497 else 498 bawrite(bp); 499 oip->i_flag |= IN_CHANGE | IN_UPDATE; 500 return (ext2_update(ovp, !DOINGASYNC(ovp))); 501 } 502 503 lastblock = (length + fs->e2fs_bsize - 1) / fs->e2fs_bsize; 504 error = ext4_ext_remove_space(oip, lastblock, flags, cred, td); 505 if (error) 506 return (error); 507 508 offset = blkoff(fs, length); 509 if (offset == 0) { 510 oip->i_size = length; 511 } else { 512 lbn = lblkno(fs, length); 513 flags |= BA_CLRBUF; 514 error = ext2_balloc(oip, lbn, offset, cred, &bp, flags); 515 if (error) { 516 return (error); 517 } 518 oip->i_size = length; 519 size = blksize(fs, oip, lbn); 520 bzero((char *)bp->b_data + offset, (u_int)(size - offset)); 521 allocbuf(bp, size); 522 if (bp->b_bufsize == fs->e2fs_bsize) 523 bp->b_flags |= B_CLUSTEROK; 524 if (flags & IO_SYNC) 525 bwrite(bp); 526 else if (DOINGASYNC(ovp)) 527 bdwrite(bp); 528 else 529 bawrite(bp); 530 } 531 532 oip->i_size = osize; 533 error = vtruncbuf(ovp, length, (int)fs->e2fs_bsize); 534 if (error) 535 return (error); 536 537 vnode_pager_setsize(ovp, length); 538 539 oip->i_size = length; 540 oip->i_flag |= IN_CHANGE | IN_UPDATE; 541 error = ext2_update(ovp, !DOINGASYNC(ovp)); 542 543 return (error); 544 } 545 546 /* 547 * Truncate the inode ip to at most length size, freeing the 548 * disk blocks. 549 */ 550 int 551 ext2_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred, 552 struct thread *td) 553 { 554 struct inode *ip; 555 int error; 556 557 ASSERT_VOP_LOCKED(vp, "ext2_truncate"); 558 559 if (length < 0) 560 return (EINVAL); 561 562 ip = VTOI(vp); 563 if (vp->v_type == VLNK && 564 ip->i_size < vp->v_mount->mnt_maxsymlinklen) { 565 #ifdef INVARIANTS 566 if (length != 0) 567 panic("ext2_truncate: partial truncate of symlink"); 568 #endif 569 bzero((char *)&ip->i_shortlink, (u_int)ip->i_size); 570 ip->i_size = 0; 571 ip->i_flag |= IN_CHANGE | IN_UPDATE; 572 return (ext2_update(vp, 1)); 573 } 574 if (ip->i_size == length) { 575 ip->i_flag |= IN_CHANGE | IN_UPDATE; 576 return (ext2_update(vp, 0)); 577 } 578 579 if (ip->i_flag & IN_E4EXTENTS) 580 error = ext2_ext_truncate(vp, length, flags, cred, td); 581 else 582 error = ext2_ind_truncate(vp, length, flags, cred, td); 583 584 return (error); 585 } 586 587 /* 588 * discard preallocated blocks 589 */ 590 int 591 ext2_inactive(struct vop_inactive_args *ap) 592 { 593 struct vnode *vp = ap->a_vp; 594 struct inode *ip = VTOI(vp); 595 struct thread *td = ap->a_td; 596 int mode, error = 0; 597 598 /* 599 * Ignore inodes related to stale file handles. 600 */ 601 if (ip->i_mode == 0) 602 goto out; 603 if (ip->i_nlink <= 0) { 604 ext2_extattr_free(ip); 605 error = ext2_truncate(vp, (off_t)0, 0, NOCRED, td); 606 if (!(ip->i_flag & IN_E4EXTENTS)) 607 ip->i_rdev = 0; 608 mode = ip->i_mode; 609 ip->i_mode = 0; 610 ip->i_flag |= IN_CHANGE | IN_UPDATE; 611 ext2_vfree(vp, ip->i_number, mode); 612 } 613 if (ip->i_flag & (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE)) 614 ext2_update(vp, 0); 615 out: 616 /* 617 * If we are done with the inode, reclaim it 618 * so that it can be reused immediately. 619 */ 620 if (ip->i_mode == 0) 621 vrecycle(vp); 622 return (error); 623 } 624 625 /* 626 * Reclaim an inode so that it can be used for other purposes. 627 */ 628 int 629 ext2_reclaim(struct vop_reclaim_args *ap) 630 { 631 struct inode *ip; 632 struct vnode *vp = ap->a_vp; 633 634 ip = VTOI(vp); 635 if (ip->i_flag & IN_LAZYMOD) { 636 ip->i_flag |= IN_MODIFIED; 637 ext2_update(vp, 0); 638 } 639 vfs_hash_remove(vp); 640 free(vp->v_data, M_EXT2NODE); 641 vp->v_data = 0; 642 return (0); 643 } 644