xref: /netbsd-src/sys/ufs/ext2fs/ext2fs_inode.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: ext2fs_inode.c,v 1.43 2004/08/15 07:19:56 mycroft Exp $	*/
2 
3 /*
4  * Copyright (c) 1982, 1986, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)ffs_inode.c	8.8 (Berkeley) 10/19/94
32  * Modified for ext2fs by Manuel Bouyer.
33  */
34 
35 /*
36  * Copyright (c) 1997 Manuel Bouyer.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. All advertising materials mentioning features or use of this software
47  *    must display the following acknowledgement:
48  *	This product includes software developed by Manuel Bouyer.
49  * 4. The name of the author may not be used to endorse or promote products
50  *    derived from this software without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
53  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
54  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
55  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
56  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
57  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
58  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
59  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
60  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
61  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
62  *
63  *	@(#)ffs_inode.c	8.8 (Berkeley) 10/19/94
64  * Modified for ext2fs by Manuel Bouyer.
65  */
66 
67 #include <sys/cdefs.h>
68 __KERNEL_RCSID(0, "$NetBSD: ext2fs_inode.c,v 1.43 2004/08/15 07:19:56 mycroft Exp $");
69 
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/mount.h>
73 #include <sys/proc.h>
74 #include <sys/file.h>
75 #include <sys/buf.h>
76 #include <sys/vnode.h>
77 #include <sys/kernel.h>
78 #include <sys/malloc.h>
79 #include <sys/trace.h>
80 #include <sys/resourcevar.h>
81 
82 #include <ufs/ufs/inode.h>
83 #include <ufs/ufs/ufsmount.h>
84 #include <ufs/ufs/ufs_extern.h>
85 
86 #include <ufs/ext2fs/ext2fs.h>
87 #include <ufs/ext2fs/ext2fs_extern.h>
88 
89 extern int prtactive;
90 
91 static int ext2fs_indirtrunc __P((struct inode *, daddr_t, daddr_t,
92 				  daddr_t, int, long *));
93 
94 /*
95  * Last reference to an inode.  If necessary, write or delete it.
96  */
97 int
98 ext2fs_inactive(v)
99 	void *v;
100 {
101 	struct vop_inactive_args /* {
102 		struct vnode *a_vp;
103 		struct proc *a_p;
104 	} */ *ap = v;
105 	struct vnode *vp = ap->a_vp;
106 	struct inode *ip = VTOI(vp);
107 	struct mount *mp;
108 	struct proc *p = ap->a_p;
109 	struct timespec ts;
110 	int error = 0;
111 
112 	if (prtactive && vp->v_usecount != 0)
113 		vprint("ext2fs_inactive: pushing active", vp);
114 	/* Get rid of inodes related to stale file handles. */
115 	if (ip->i_e2fs_mode == 0 || ip->i_e2fs_dtime != 0)
116 		goto out;
117 
118 	error = 0;
119 	if (ip->i_e2fs_nlink == 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
120 		vn_start_write(vp, &mp, V_WAIT | V_LOWER);
121 		if (ip->i_e2fs_size != 0) {
122 			error = VOP_TRUNCATE(vp, (off_t)0, 0, NOCRED, NULL);
123 		}
124 		TIMEVAL_TO_TIMESPEC(&time, &ts);
125 		ip->i_e2fs_dtime = ts.tv_sec;
126 		ip->i_flag |= IN_CHANGE | IN_UPDATE;
127 		VOP_VFREE(vp, ip->i_number, ip->i_e2fs_mode);
128 		vn_finished_write(mp, V_LOWER);
129 	}
130 	if (ip->i_flag & (IN_CHANGE | IN_UPDATE | IN_MODIFIED)) {
131 		vn_start_write(vp, &mp, V_WAIT | V_LOWER);
132 		VOP_UPDATE(vp, NULL, NULL, 0);
133 		vn_finished_write(mp, V_LOWER);
134 	}
135 out:
136 	VOP_UNLOCK(vp, 0);
137 	/*
138 	 * If we are done with the inode, reclaim it
139 	 * so that it can be reused immediately.
140 	 */
141 	if (ip->i_e2fs_dtime != 0)
142 		vrecycle(vp, NULL, p);
143 	return (error);
144 }
145 
146 
147 /*
148  * Update the access, modified, and inode change times as specified by the
149  * IACCESS, IUPDATE, and ICHANGE flags respectively. The IMODIFIED flag is
150  * used to specify that the inode needs to be updated but that the times have
151  * already been set. The access and modified times are taken from the second
152  * and third parameters; the inode change time is always taken from the current
153  * time. If UPDATE_WAIT or UPDATE_DIROP is set, then wait for the disk
154  * write of the inode to complete.
155  */
156 int
157 ext2fs_update(v)
158 	void *v;
159 {
160 	struct vop_update_args /* {
161 		struct vnode *a_vp;
162 		struct timespec *a_access;
163 		struct timespec *a_modify;
164 		int a_flags;
165 	} */ *ap = v;
166 	struct m_ext2fs *fs;
167 	struct buf *bp;
168 	struct inode *ip;
169 	int error;
170 	struct timespec ts;
171 	caddr_t cp;
172 	int flags;
173 
174 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
175 		return (0);
176 	ip = VTOI(ap->a_vp);
177 	TIMEVAL_TO_TIMESPEC(&time, &ts);
178 	EXT2FS_ITIMES(ip,
179 	    ap->a_access ? ap->a_access : &ts,
180 	    ap->a_modify ? ap->a_modify : &ts, &ts);
181 	if (ap->a_flags & UPDATE_CLOSE)
182 		flags = ip->i_flag & (IN_MODIFIED | IN_ACCESSED);
183 	else
184 		flags = ip->i_flag & IN_MODIFIED;
185 	if (flags == 0)
186 		return (0);
187 	fs = ip->i_e2fs;
188 
189 	error = bread(ip->i_devvp,
190 			  fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
191 			  (int)fs->e2fs_bsize, NOCRED, &bp);
192 	if (error) {
193 		brelse(bp);
194 		return (error);
195 	}
196 	ip->i_flag &= ~(IN_MODIFIED | IN_ACCESSED);
197 	cp = (caddr_t)bp->b_data +
198 	    (ino_to_fsbo(fs, ip->i_number) * EXT2_DINODE_SIZE);
199 	e2fs_isave(ip->i_din.e2fs_din, (struct ext2fs_dinode *)cp);
200 	if ((ap->a_flags & (UPDATE_WAIT|UPDATE_DIROP)) != 0 &&
201 	    (flags & IN_MODIFIED) != 0 &&
202 	    (ap->a_vp->v_mount->mnt_flag & MNT_ASYNC) == 0)
203 		return (bwrite(bp));
204 	else {
205 		bdwrite(bp);
206 		return (0);
207 	}
208 }
209 
210 #define	SINGLE	0	/* index of single indirect block */
211 #define	DOUBLE	1	/* index of double indirect block */
212 #define	TRIPLE	2	/* index of triple indirect block */
213 /*
214  * Truncate the inode oip to at most length size, freeing the
215  * disk blocks.
216  */
217 int
218 ext2fs_truncate(v)
219 	void *v;
220 {
221 	struct vop_truncate_args /* {
222 		struct vnode *a_vp;
223 		off_t a_length;
224 		int a_flags;
225 		struct ucred *a_cred;
226 		struct proc *a_p;
227 	} */ *ap = v;
228 	struct vnode *ovp = ap->a_vp;
229 	daddr_t lastblock;
230 	struct inode *oip = VTOI(ovp);
231 	daddr_t bn, lastiblock[NIADDR], indir_lbn[NIADDR];
232 	/* XXX ondisk32 */
233 	int32_t oldblks[NDADDR + NIADDR], newblks[NDADDR + NIADDR];
234 	off_t length = ap->a_length;
235 	struct m_ext2fs *fs;
236 	int offset, size, level;
237 	long count, blocksreleased = 0;
238 	int i, ioflag, nblocks;
239 	int error, allerror = 0;
240 	off_t osize;
241 	int sync;
242 	struct ufsmount *ump = oip->i_ump;
243 
244 	if (length < 0)
245 		return (EINVAL);
246 
247 	if (ovp->v_type == VLNK &&
248 	    (oip->i_e2fs_size < ump->um_maxsymlinklen ||
249 	     (ump->um_maxsymlinklen == 0 && oip->i_e2fs_nblock == 0))) {
250 		KDASSERT(length == 0);
251 		memset((char *)&oip->i_din.e2fs_din->e2di_shortlink, 0,
252 			(u_int)oip->i_e2fs_size);
253 		oip->i_e2fs_size = 0;
254 		oip->i_flag |= IN_CHANGE | IN_UPDATE;
255 		return (VOP_UPDATE(ovp, NULL, NULL, 0));
256 	}
257 	if (oip->i_e2fs_size == length) {
258 		oip->i_flag |= IN_CHANGE | IN_UPDATE;
259 		return (VOP_UPDATE(ovp, NULL, NULL, 0));
260 	}
261 	fs = oip->i_e2fs;
262 	if (length > ump->um_maxfilesize)
263 		return (EFBIG);
264 
265 	osize = oip->i_e2fs_size;
266 	ioflag = ap->a_flags;
267 
268 	/*
269 	 * Lengthen the size of the file. We must ensure that the
270 	 * last byte of the file is allocated. Since the smallest
271 	 * value of osize is 0, length will be at least 1.
272 	 */
273 	if (osize < length) {
274 		error = ufs_balloc_range(ovp, length - 1, 1, ap->a_cred,
275 		    ioflag & IO_SYNC ? B_SYNC : 0);
276 		if (error) {
277 			(void) VOP_TRUNCATE(ovp, osize, ioflag & IO_SYNC,
278 			    ap->a_cred, ap->a_p);
279 			return (error);
280 		}
281 		uvm_vnp_setsize(ovp, length);
282 		oip->i_flag |= IN_CHANGE | IN_UPDATE;
283 		KASSERT(ovp->v_size == oip->i_size);
284 		return (VOP_UPDATE(ovp, NULL, NULL, 0));
285 	}
286 	/*
287 	 * Shorten the size of the file. If the file is not being
288 	 * truncated to a block boundry, the contents of the
289 	 * partial block following the end of the file must be
290 	 * zero'ed in case it ever become accessible again because
291 	 * of subsequent file growth.
292 	 */
293 	offset = blkoff(fs, length);
294 	if (offset != 0) {
295 		size = fs->e2fs_bsize;
296 
297 		/* XXXUBC we should handle more than just VREG */
298 		uvm_vnp_zerorange(ovp, length, size - offset);
299 	}
300 	oip->i_e2fs_size = length;
301 	uvm_vnp_setsize(ovp, length);
302 	/*
303 	 * Calculate index into inode's block list of
304 	 * last direct and indirect blocks (if any)
305 	 * which we want to keep.  Lastblock is -1 when
306 	 * the file is truncated to 0.
307 	 */
308 	lastblock = lblkno(fs, length + fs->e2fs_bsize - 1) - 1;
309 	lastiblock[SINGLE] = lastblock - NDADDR;
310 	lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
311 	lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
312 	nblocks = btodb(fs->e2fs_bsize);
313 	/*
314 	 * Update file and block pointers on disk before we start freeing
315 	 * blocks.  If we crash before free'ing blocks below, the blocks
316 	 * will be returned to the free list.  lastiblock values are also
317 	 * normalized to -1 for calls to ext2fs_indirtrunc below.
318 	 */
319 	memcpy((caddr_t)oldblks, (caddr_t)&oip->i_e2fs_blocks[0], sizeof oldblks);
320 	sync = 0;
321 	for (level = TRIPLE; level >= SINGLE; level--) {
322 		if (lastiblock[level] < 0 && oldblks[NDADDR + level] != 0) {
323 			sync = 1;
324 			oip->i_e2fs_blocks[NDADDR + level] = 0;
325 			lastiblock[level] = -1;
326 		}
327 	}
328 	for (i = 0; i < NDADDR; i++) {
329 		if (i > lastblock && oldblks[i] != 0) {
330 			sync = 1;
331 			oip->i_e2fs_blocks[i] = 0;
332 		}
333 	}
334 	oip->i_flag |= IN_CHANGE | IN_UPDATE;
335 	if (sync) {
336 		error = VOP_UPDATE(ovp, NULL, NULL, UPDATE_WAIT);
337 		if (error && !allerror)
338 			allerror = error;
339 	}
340 
341 	/*
342 	 * Having written the new inode to disk, save its new configuration
343 	 * and put back the old block pointers long enough to process them.
344 	 * Note that we save the new block configuration so we can check it
345 	 * when we are done.
346 	 */
347 	memcpy((caddr_t)newblks, (caddr_t)&oip->i_e2fs_blocks[0], sizeof newblks);
348 	memcpy((caddr_t)&oip->i_e2fs_blocks[0], (caddr_t)oldblks, sizeof oldblks);
349 
350 	oip->i_e2fs_size = osize;
351 	error = vtruncbuf(ovp, lastblock + 1, 0, 0);
352 	if (error && !allerror)
353 		allerror = error;
354 
355 	/*
356 	 * Indirect blocks first.
357 	 */
358 	indir_lbn[SINGLE] = -NDADDR;
359 	indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) -1;
360 	indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
361 	for (level = TRIPLE; level >= SINGLE; level--) {
362 		/* XXX ondisk32 */
363 		bn = fs2h32(oip->i_e2fs_blocks[NDADDR + level]);
364 		if (bn != 0) {
365 			error = ext2fs_indirtrunc(oip, indir_lbn[level],
366 			    fsbtodb(fs, bn), lastiblock[level], level, &count);
367 			if (error)
368 				allerror = error;
369 			blocksreleased += count;
370 			if (lastiblock[level] < 0) {
371 				oip->i_e2fs_blocks[NDADDR + level] = 0;
372 				ext2fs_blkfree(oip, bn);
373 				blocksreleased += nblocks;
374 			}
375 		}
376 		if (lastiblock[level] >= 0)
377 			goto done;
378 	}
379 
380 	/*
381 	 * All whole direct blocks or frags.
382 	 */
383 	for (i = NDADDR - 1; i > lastblock; i--) {
384 		/* XXX ondisk32 */
385 		bn = fs2h32(oip->i_e2fs_blocks[i]);
386 		if (bn == 0)
387 			continue;
388 		oip->i_e2fs_blocks[i] = 0;
389 		ext2fs_blkfree(oip, bn);
390 		blocksreleased += btodb(fs->e2fs_bsize);
391 	}
392 
393 done:
394 #ifdef DIAGNOSTIC
395 	for (level = SINGLE; level <= TRIPLE; level++)
396 		if (newblks[NDADDR + level] !=
397 		    oip->i_e2fs_blocks[NDADDR + level])
398 			panic("ext2fs_truncate1");
399 	for (i = 0; i < NDADDR; i++)
400 		if (newblks[i] != oip->i_e2fs_blocks[i])
401 			panic("ext2fs_truncate2");
402 	if (length == 0 &&
403 	    (!LIST_EMPTY(&ovp->v_cleanblkhd) ||
404 	     !LIST_EMPTY(&ovp->v_dirtyblkhd)))
405 		panic("ext2fs_truncate3");
406 #endif /* DIAGNOSTIC */
407 	/*
408 	 * Put back the real size.
409 	 */
410 	oip->i_e2fs_size = length;
411 	oip->i_e2fs_nblock -= blocksreleased;
412 	oip->i_flag |= IN_CHANGE;
413 	KASSERT(ovp->v_type != VREG || ovp->v_size == oip->i_size);
414 	return (allerror);
415 }
416 
417 /*
418  * Release blocks associated with the inode ip and stored in the indirect
419  * block bn.  Blocks are free'd in LIFO order up to (but not including)
420  * lastbn.  If level is greater than SINGLE, the block is an indirect block
421  * and recursive calls to indirtrunc must be used to cleanse other indirect
422  * blocks.
423  *
424  * NB: triple indirect blocks are untested.
425  */
426 static int
427 ext2fs_indirtrunc(ip, lbn, dbn, lastbn, level, countp)
428 	struct inode *ip;
429 	daddr_t lbn, lastbn;
430 	daddr_t dbn;
431 	int level;
432 	long *countp;
433 {
434 	int i;
435 	struct buf *bp;
436 	struct m_ext2fs *fs = ip->i_e2fs;
437 	int32_t *bap;	/* XXX ondisk32 */
438 	struct vnode *vp;
439 	daddr_t nb, nlbn, last;
440 	int32_t *copy = NULL;	/* XXX ondisk32 */
441 	long blkcount, factor;
442 	int nblocks, blocksreleased = 0;
443 	int error = 0, allerror = 0;
444 
445 	/*
446 	 * Calculate index in current block of last
447 	 * block to be kept.  -1 indicates the entire
448 	 * block so we need not calculate the index.
449 	 */
450 	factor = 1;
451 	for (i = SINGLE; i < level; i++)
452 		factor *= NINDIR(fs);
453 	last = lastbn;
454 	if (lastbn > 0)
455 		last /= factor;
456 	nblocks = btodb(fs->e2fs_bsize);
457 	/*
458 	 * Get buffer of block pointers, zero those entries corresponding
459 	 * to blocks to be free'd, and update on disk copy first.  Since
460 	 * double(triple) indirect before single(double) indirect, calls
461 	 * to bmap on these blocks will fail.  However, we already have
462 	 * the on disk address, so we have to set the b_blkno field
463 	 * explicitly instead of letting bread do everything for us.
464 	 */
465 	vp = ITOV(ip);
466 	bp = getblk(vp, lbn, (int)fs->e2fs_bsize, 0, 0);
467 	if (bp->b_flags & (B_DONE | B_DELWRI)) {
468 		/* Braces must be here in case trace evaluates to nothing. */
469 		trace(TR_BREADHIT, pack(vp, fs->e2fs_bsize), lbn);
470 	} else {
471 		trace(TR_BREADMISS, pack(vp, fs->e2fs_bsize), lbn);
472 		curproc->p_stats->p_ru.ru_inblock++;	/* pay for read */
473 		bp->b_flags |= B_READ;
474 		if (bp->b_bcount > bp->b_bufsize)
475 			panic("ext2fs_indirtrunc: bad buffer size");
476 		bp->b_blkno = dbn;
477 		VOP_STRATEGY(vp, bp);
478 		error = biowait(bp);
479 	}
480 	if (error) {
481 		brelse(bp);
482 		*countp = 0;
483 		return (error);
484 	}
485 
486 	bap = (int32_t *)bp->b_data;	/* XXX ondisk32 */
487 	if (lastbn >= 0) {
488 		/* XXX ondisk32 */
489 		MALLOC(copy, int32_t *, fs->e2fs_bsize, M_TEMP, M_WAITOK);
490 		memcpy((caddr_t)copy, (caddr_t)bap, (u_int)fs->e2fs_bsize);
491 		memset((caddr_t)&bap[last + 1], 0,
492 			(u_int)(NINDIR(fs) - (last + 1)) * sizeof (u_int32_t));
493 		error = bwrite(bp);
494 		if (error)
495 			allerror = error;
496 		bap = copy;
497 	}
498 
499 	/*
500 	 * Recursively free totally unused blocks.
501 	 */
502 	for (i = NINDIR(fs) - 1,
503 		nlbn = lbn + 1 - i * factor; i > last;
504 		i--, nlbn += factor) {
505 		/* XXX ondisk32 */
506 		nb = fs2h32(bap[i]);
507 		if (nb == 0)
508 			continue;
509 		if (level > SINGLE) {
510 			error = ext2fs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
511 						   (daddr_t)-1, level - 1,
512 						   &blkcount);
513 			if (error)
514 				allerror = error;
515 			blocksreleased += blkcount;
516 		}
517 		ext2fs_blkfree(ip, nb);
518 		blocksreleased += nblocks;
519 	}
520 
521 	/*
522 	 * Recursively free last partial block.
523 	 */
524 	if (level > SINGLE && lastbn >= 0) {
525 		last = lastbn % factor;
526 		/* XXX ondisk32 */
527 		nb = fs2h32(bap[i]);
528 		if (nb != 0) {
529 			error = ext2fs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
530 						   last, level - 1, &blkcount);
531 			if (error)
532 				allerror = error;
533 			blocksreleased += blkcount;
534 		}
535 	}
536 
537 	if (copy != NULL) {
538 		FREE(copy, M_TEMP);
539 	} else {
540 		bp->b_flags |= B_INVAL;
541 		brelse(bp);
542 	}
543 
544 	*countp = blocksreleased;
545 	return (allerror);
546 }
547