1 /* $NetBSD: lfs_alloc.c,v 1.83 2005/05/29 21:25:24 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1999, 2000, 2001, 2002, 2003 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Konrad E. Schroder <perseant@hhhh.org>. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 /* 39 * Copyright (c) 1991, 1993 40 * The Regents of the University of California. All rights reserved. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)lfs_alloc.c 8.4 (Berkeley) 1/4/94 67 */ 68 69 #include <sys/cdefs.h> 70 __KERNEL_RCSID(0, "$NetBSD: lfs_alloc.c,v 1.83 2005/05/29 21:25:24 christos Exp $"); 71 72 #if defined(_KERNEL_OPT) 73 #include "opt_quota.h" 74 #endif 75 76 #include <sys/param.h> 77 #include <sys/systm.h> 78 #include <sys/kernel.h> 79 #include <sys/buf.h> 80 #include <sys/lock.h> 81 #include <sys/vnode.h> 82 #include <sys/syslog.h> 83 #include <sys/mount.h> 84 #include <sys/pool.h> 85 #include <sys/proc.h> 86 #include <sys/tree.h> 87 88 #include <ufs/ufs/quota.h> 89 #include <ufs/ufs/inode.h> 90 #include <ufs/ufs/ufsmount.h> 91 #include <ufs/ufs/ufs_extern.h> 92 93 #include <ufs/lfs/lfs.h> 94 #include <ufs/lfs/lfs_extern.h> 95 96 extern struct lock ufs_hashlock; 97 98 static int extend_ifile(struct lfs *, struct ucred *); 99 static int lfs_ialloc(struct lfs *, struct vnode *, ino_t, int, 100 struct vnode **); 101 102 /* 103 * Allocate a particular inode with a particular version number, freeing 104 * any previous versions of this inode that may have gone before. 105 * Used by the roll-forward code. 106 * 107 * XXX this function does not have appropriate locking to be used on a live fs; 108 * XXX but something similar could probably be used for an "undelete" call. 109 * 110 * Called with the Ifile inode locked. 111 */ 112 int 113 lfs_rf_valloc(struct lfs *fs, ino_t ino, int vers, struct proc *p, 114 struct vnode **vpp) 115 { 116 IFILE *ifp; 117 struct buf *bp, *cbp; 118 struct vnode *vp; 119 struct inode *ip; 120 ino_t tino, oldnext; 121 int error; 122 CLEANERINFO *cip; 123 124 ASSERT_SEGLOCK(fs); /* XXX it doesn't, really */ 125 126 /* 127 * First, just try a vget. If the version number is the one we want, 128 * we don't have to do anything else. If the version number is wrong, 129 * take appropriate action. 130 */ 131 error = VFS_VGET(fs->lfs_ivnode->v_mount, ino, &vp); 132 if (error == 0) { 133 DLOG((DLOG_RF, "lfs_rf_valloc[1]: ino %d vp %p\n", ino, vp)); 134 135 *vpp = vp; 136 ip = VTOI(vp); 137 if (ip->i_gen == vers) 138 return 0; 139 else if (ip->i_gen < vers) { 140 VOP_TRUNCATE(vp, (off_t)0, 0, NOCRED, p); 141 ip->i_gen = ip->i_ffs1_gen = vers; 142 LFS_SET_UINO(ip, IN_CHANGE | IN_UPDATE); 143 return 0; 144 } else { 145 DLOG((DLOG_RF, "ino %d: sought version %d, got %d\n", 146 ino, vers, ip->i_ffs1_gen)); 147 vput(vp); 148 *vpp = NULLVP; 149 return EEXIST; 150 } 151 } 152 153 /* 154 * The inode is not in use. Find it on the free list. 155 */ 156 /* If the Ifile is too short to contain this inum, extend it */ 157 while (VTOI(fs->lfs_ivnode)->i_size <= (ino / 158 fs->lfs_ifpb + fs->lfs_cleansz + fs->lfs_segtabsz) 159 << fs->lfs_bshift) { 160 extend_ifile(fs, NOCRED); 161 } 162 163 LFS_IENTRY(ifp, fs, ino, bp); 164 oldnext = ifp->if_nextfree; 165 ifp->if_version = vers; 166 brelse(bp); 167 168 LFS_GET_HEADFREE(fs, cip, cbp, &ino); 169 if (ino) { 170 LFS_PUT_HEADFREE(fs, cip, cbp, oldnext); 171 } else { 172 tino = ino; 173 while (1) { 174 LFS_IENTRY(ifp, fs, tino, bp); 175 if (ifp->if_nextfree == ino || 176 ifp->if_nextfree == LFS_UNUSED_INUM) 177 break; 178 tino = ifp->if_nextfree; 179 brelse(bp); 180 } 181 if (ifp->if_nextfree == LFS_UNUSED_INUM) { 182 brelse(bp); 183 return ENOENT; 184 } 185 ifp->if_nextfree = oldnext; 186 LFS_BWRITE_LOG(bp); 187 } 188 189 error = lfs_ialloc(fs, fs->lfs_ivnode, ino, vers, &vp); 190 if (error == 0) { 191 /* 192 * Make it VREG so we can put blocks on it. We will change 193 * this later if it turns out to be some other kind of file. 194 */ 195 ip = VTOI(vp); 196 ip->i_mode = ip->i_ffs1_mode = IFREG; 197 ip->i_nlink = ip->i_ffs1_nlink = 1; 198 ip->i_ffs_effnlink = 1; 199 ufs_vinit(vp->v_mount, lfs_specop_p, lfs_fifoop_p, &vp); 200 ip = VTOI(vp); 201 202 DLOG((DLOG_RF, "lfs_rf_valloc: ino %d vp %p\n", ino, vp)); 203 204 /* The dirop-nature of this vnode is past */ 205 lfs_unmark_vnode(vp); 206 (void)lfs_vunref(vp); 207 vp->v_flag &= ~VDIROP; 208 simple_lock(&fs->lfs_interlock); 209 simple_lock(&lfs_subsys_lock); 210 --lfs_dirvcount; 211 simple_unlock(&lfs_subsys_lock); 212 TAILQ_REMOVE(&fs->lfs_dchainhd, ip, i_lfs_dchain); 213 simple_unlock(&fs->lfs_interlock); 214 } 215 *vpp = vp; 216 return error; 217 } 218 219 /* 220 * Add a new block to the Ifile, to accommodate future file creations. 221 * Called with the segment lock held. 222 */ 223 static int 224 extend_ifile(struct lfs *fs, struct ucred *cred) 225 { 226 struct vnode *vp; 227 struct inode *ip; 228 IFILE *ifp; 229 IFILE_V1 *ifp_v1; 230 struct buf *bp, *cbp; 231 int error; 232 daddr_t i, blkno, xmax; 233 ino_t oldlast; 234 CLEANERINFO *cip; 235 236 ASSERT_SEGLOCK(fs); 237 238 vp = fs->lfs_ivnode; 239 ip = VTOI(vp); 240 blkno = lblkno(fs, ip->i_size); 241 if ((error = VOP_BALLOC(vp, ip->i_size, fs->lfs_bsize, cred, 0, 242 &bp)) != 0) { 243 return (error); 244 } 245 ip->i_size += fs->lfs_bsize; 246 ip->i_ffs1_size = ip->i_size; 247 uvm_vnp_setsize(vp, ip->i_size); 248 249 i = (blkno - fs->lfs_segtabsz - fs->lfs_cleansz) * 250 fs->lfs_ifpb; 251 LFS_GET_HEADFREE(fs, cip, cbp, &oldlast); 252 LFS_PUT_HEADFREE(fs, cip, cbp, i); 253 #ifdef DIAGNOSTIC 254 if (fs->lfs_freehd == LFS_UNUSED_INUM) 255 panic("inode 0 allocated [2]"); 256 #endif /* DIAGNOSTIC */ 257 xmax = i + fs->lfs_ifpb; 258 259 if (fs->lfs_version == 1) { 260 for (ifp_v1 = (IFILE_V1 *)bp->b_data; i < xmax; ++ifp_v1) { 261 ifp_v1->if_version = 1; 262 ifp_v1->if_daddr = LFS_UNUSED_DADDR; 263 ifp_v1->if_nextfree = ++i; 264 } 265 ifp_v1--; 266 ifp_v1->if_nextfree = oldlast; 267 } else { 268 for (ifp = (IFILE *)bp->b_data; i < xmax; ++ifp) { 269 ifp->if_version = 1; 270 ifp->if_daddr = LFS_UNUSED_DADDR; 271 ifp->if_nextfree = ++i; 272 } 273 ifp--; 274 ifp->if_nextfree = oldlast; 275 } 276 LFS_PUT_TAILFREE(fs, cip, cbp, xmax - 1); 277 278 (void) LFS_BWRITE_LOG(bp); /* Ifile */ 279 280 return 0; 281 } 282 283 /* Allocate a new inode. */ 284 /* ARGSUSED */ 285 /* VOP_BWRITE 2i times */ 286 int 287 lfs_valloc(void *v) 288 { 289 struct vop_valloc_args /* { 290 struct vnode *a_pvp; 291 int a_mode; 292 struct ucred *a_cred; 293 struct vnode **a_vpp; 294 } */ *ap = v; 295 struct lfs *fs; 296 struct buf *bp, *cbp; 297 struct ifile *ifp; 298 ino_t new_ino; 299 int error; 300 int new_gen; 301 CLEANERINFO *cip; 302 303 fs = VTOI(ap->a_pvp)->i_lfs; 304 if (fs->lfs_ronly) 305 return EROFS; 306 307 ASSERT_NO_SEGLOCK(fs); 308 309 lfs_seglock(fs, SEGM_PROT); 310 vn_lock(fs->lfs_ivnode, LK_EXCLUSIVE); 311 312 /* Get the head of the freelist. */ 313 LFS_GET_HEADFREE(fs, cip, cbp, &new_ino); 314 315 #ifdef DIAGNOSTIC 316 if (new_ino == LFS_UNUSED_INUM) { 317 #ifdef DEBUG 318 lfs_dump_super(fs); 319 #endif /* DEBUG */ 320 panic("inode 0 allocated [1]"); 321 } 322 #endif /* DIAGNOSTIC */ 323 DLOG((DLOG_ALLOC, "lfs_valloc: allocate inode %d\n", new_ino)); 324 325 /* 326 * Remove the inode from the free list and write the new start 327 * of the free list into the superblock. 328 */ 329 LFS_IENTRY(ifp, fs, new_ino, bp); 330 if (ifp->if_daddr != LFS_UNUSED_DADDR) 331 panic("lfs_valloc: inuse inode %d on the free list", new_ino); 332 LFS_PUT_HEADFREE(fs, cip, cbp, ifp->if_nextfree); 333 DLOG((DLOG_ALLOC, "lfs_valloc: headfree %d -> %d\n", new_ino, 334 ifp->if_nextfree)); 335 336 new_gen = ifp->if_version; /* version was updated by vfree */ 337 brelse(bp); 338 339 /* Extend IFILE so that the next lfs_valloc will succeed. */ 340 if (fs->lfs_freehd == LFS_UNUSED_INUM) { 341 if ((error = extend_ifile(fs, ap->a_cred)) != 0) { 342 LFS_PUT_HEADFREE(fs, cip, cbp, new_ino); 343 VOP_UNLOCK(fs->lfs_ivnode, 0); 344 lfs_segunlock(fs); 345 return error; 346 } 347 } 348 #ifdef DIAGNOSTIC 349 if (fs->lfs_freehd == LFS_UNUSED_INUM) 350 panic("inode 0 allocated [3]"); 351 #endif /* DIAGNOSTIC */ 352 353 /* Set superblock modified bit and increment file count. */ 354 simple_lock(&fs->lfs_interlock); 355 fs->lfs_fmod = 1; 356 simple_unlock(&fs->lfs_interlock); 357 ++fs->lfs_nfiles; 358 359 VOP_UNLOCK(fs->lfs_ivnode, 0); 360 lfs_segunlock(fs); 361 362 return lfs_ialloc(fs, ap->a_pvp, new_ino, new_gen, ap->a_vpp); 363 } 364 365 /* 366 * Finish allocating a new inode, given an inode and generation number. 367 */ 368 static int 369 lfs_ialloc(struct lfs *fs, struct vnode *pvp, ino_t new_ino, int new_gen, 370 struct vnode **vpp) 371 { 372 struct inode *ip; 373 struct vnode *vp; 374 375 ASSERT_NO_SEGLOCK(fs); 376 377 vp = *vpp; 378 lockmgr(&ufs_hashlock, LK_EXCLUSIVE, 0); 379 /* Create an inode to associate with the vnode. */ 380 lfs_vcreate(pvp->v_mount, new_ino, vp); 381 382 ip = VTOI(vp); 383 LFS_SET_UINO(ip, IN_CHANGE); 384 /* on-disk structure has been zeroed out by lfs_vcreate */ 385 ip->i_din.ffs1_din->di_inumber = new_ino; 386 387 /* Note no blocks yet */ 388 ip->i_lfs_hiblk = -1; 389 390 /* Set a new generation number for this inode. */ 391 if (new_gen) { 392 ip->i_gen = new_gen; 393 ip->i_ffs1_gen = new_gen; 394 } 395 396 /* Insert into the inode hash table. */ 397 ufs_ihashins(ip); 398 lockmgr(&ufs_hashlock, LK_RELEASE, 0); 399 400 ufs_vinit(vp->v_mount, lfs_specop_p, lfs_fifoop_p, vpp); 401 vp = *vpp; 402 ip = VTOI(vp); 403 404 memset(ip->i_lfs_fragsize, 0, NDADDR * sizeof(*ip->i_lfs_fragsize)); 405 406 uvm_vnp_setsize(vp, 0); 407 lfs_mark_vnode(vp); 408 genfs_node_init(vp, &lfs_genfsops); 409 VREF(ip->i_devvp); 410 return (0); 411 } 412 413 /* Create a new vnode/inode pair and initialize what fields we can. */ 414 void 415 lfs_vcreate(struct mount *mp, ino_t ino, struct vnode *vp) 416 { 417 struct inode *ip; 418 struct ufs1_dinode *dp; 419 struct ufsmount *ump; 420 #ifdef QUOTA 421 int i; 422 #endif 423 424 /* Get a pointer to the private mount structure. */ 425 ump = VFSTOUFS(mp); 426 427 ASSERT_NO_SEGLOCK(ump->um_lfs); 428 429 /* Initialize the inode. */ 430 ip = pool_get(&lfs_inode_pool, PR_WAITOK); 431 memset(ip, 0, sizeof(*ip)); 432 dp = pool_get(&lfs_dinode_pool, PR_WAITOK); 433 memset(dp, 0, sizeof(*dp)); 434 ip->inode_ext.lfs = pool_get(&lfs_inoext_pool, PR_WAITOK); 435 memset(ip->inode_ext.lfs, 0, sizeof(*ip->inode_ext.lfs)); 436 vp->v_data = ip; 437 ip->i_din.ffs1_din = dp; 438 ip->i_ump = ump; 439 ip->i_vnode = vp; 440 ip->i_devvp = ump->um_devvp; 441 ip->i_dev = ump->um_dev; 442 ip->i_number = dp->di_inumber = ino; 443 ip->i_lfs = ump->um_lfs; 444 ip->i_lfs_effnblks = 0; 445 SPLAY_INIT(&ip->i_lfs_lbtree); 446 ip->i_lfs_nbtree = 0; 447 #ifdef QUOTA 448 for (i = 0; i < MAXQUOTAS; i++) 449 ip->i_dquot[i] = NODQUOT; 450 #endif 451 #ifdef DEBUG 452 if (ino == LFS_IFILE_INUM) 453 vp->v_vnlock->lk_wmesg = "inlock"; 454 #endif 455 } 456 457 /* Free an inode. */ 458 /* ARGUSED */ 459 /* VOP_BWRITE 2i times */ 460 int 461 lfs_vfree(void *v) 462 { 463 struct vop_vfree_args /* { 464 struct vnode *a_pvp; 465 ino_t a_ino; 466 int a_mode; 467 } */ *ap = v; 468 SEGUSE *sup; 469 CLEANERINFO *cip; 470 struct buf *cbp, *bp; 471 struct ifile *ifp; 472 struct inode *ip; 473 struct vnode *vp; 474 struct lfs *fs; 475 daddr_t old_iaddr; 476 ino_t ino, otail; 477 int s; 478 479 /* Get the inode number and file system. */ 480 vp = ap->a_pvp; 481 ip = VTOI(vp); 482 fs = ip->i_lfs; 483 ino = ip->i_number; 484 485 ASSERT_NO_SEGLOCK(fs); 486 487 /* Drain of pending writes */ 488 simple_lock(&vp->v_interlock); 489 s = splbio(); 490 if (fs->lfs_version > 1 && WRITEINPROG(vp)) 491 ltsleep(vp, (PRIBIO+1), "lfs_vfree", 0, &vp->v_interlock); 492 splx(s); 493 simple_unlock(&vp->v_interlock); 494 495 lfs_seglock(fs, SEGM_PROT); 496 vn_lock(fs->lfs_ivnode, LK_EXCLUSIVE); 497 498 lfs_unmark_vnode(vp); 499 if (vp->v_flag & VDIROP) { 500 vp->v_flag &= ~VDIROP; 501 simple_lock(&fs->lfs_interlock); 502 simple_lock(&lfs_subsys_lock); 503 --lfs_dirvcount; 504 simple_unlock(&lfs_subsys_lock); 505 TAILQ_REMOVE(&fs->lfs_dchainhd, ip, i_lfs_dchain); 506 simple_unlock(&fs->lfs_interlock); 507 wakeup(&lfs_dirvcount); 508 lfs_vunref(vp); 509 } 510 511 LFS_CLR_UINO(ip, IN_ACCESSED|IN_CLEANING|IN_MODIFIED); 512 ip->i_flag &= ~IN_ALLMOD; 513 514 /* 515 * Set the ifile's inode entry to unused, increment its version number 516 * and link it onto the free chain. 517 */ 518 LFS_IENTRY(ifp, fs, ino, bp); 519 old_iaddr = ifp->if_daddr; 520 ifp->if_daddr = LFS_UNUSED_DADDR; 521 ++ifp->if_version; 522 if (fs->lfs_version == 1) { 523 LFS_GET_HEADFREE(fs, cip, cbp, &(ifp->if_nextfree)); 524 LFS_PUT_HEADFREE(fs, cip, cbp, ino); 525 (void) LFS_BWRITE_LOG(bp); /* Ifile */ 526 } else { 527 ifp->if_nextfree = LFS_UNUSED_INUM; 528 /* 529 * XXX Writing the freed node here means that it might not 530 * XXX make it into the free list in the event of a crash 531 * XXX (the ifile could be written before the rest of this 532 * XXX completes). 533 */ 534 (void) LFS_BWRITE_LOG(bp); /* Ifile */ 535 LFS_GET_TAILFREE(fs, cip, cbp, &otail); 536 LFS_IENTRY(ifp, fs, otail, bp); 537 ifp->if_nextfree = ino; 538 LFS_BWRITE_LOG(bp); 539 LFS_PUT_TAILFREE(fs, cip, cbp, ino); 540 DLOG((DLOG_ALLOC, "lfs_vfree: tailfree %d -> %d\n", otail, 541 ino)); 542 } 543 #ifdef DIAGNOSTIC 544 if (ino == LFS_UNUSED_INUM) { 545 panic("inode 0 freed"); 546 } 547 #endif /* DIAGNOSTIC */ 548 if (old_iaddr != LFS_UNUSED_DADDR) { 549 LFS_SEGENTRY(sup, fs, dtosn(fs, old_iaddr), bp); 550 #ifdef DIAGNOSTIC 551 if (sup->su_nbytes < sizeof (struct ufs1_dinode)) { 552 printf("lfs_vfree: negative byte count" 553 " (segment %" PRIu32 " short by %d)\n", 554 dtosn(fs, old_iaddr), 555 (int)sizeof (struct ufs1_dinode) - 556 sup->su_nbytes); 557 panic("lfs_vfree: negative byte count"); 558 sup->su_nbytes = sizeof (struct ufs1_dinode); 559 } 560 #endif 561 sup->su_nbytes -= sizeof (struct ufs1_dinode); 562 LFS_WRITESEGENTRY(sup, fs, dtosn(fs, old_iaddr), bp); /* Ifile */ 563 } 564 565 /* Set superblock modified bit and decrement file count. */ 566 simple_lock(&fs->lfs_interlock); 567 fs->lfs_fmod = 1; 568 simple_unlock(&fs->lfs_interlock); 569 --fs->lfs_nfiles; 570 571 VOP_UNLOCK(fs->lfs_ivnode, 0); 572 lfs_segunlock(fs); 573 574 return (0); 575 } 576