xref: /freebsd/sbin/fsck_ffs/pass5.c (revision 595e514d0df2bac5b813d35f83e32875dbf16a83)
1 /*
2  * Copyright (c) 1980, 1986, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if 0
31 #ifndef lint
32 static const char sccsid[] = "@(#)pass5.c	8.9 (Berkeley) 4/28/95";
33 #endif /* not lint */
34 #endif
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include <sys/param.h>
39 #include <sys/sysctl.h>
40 
41 #include <ufs/ufs/dinode.h>
42 #include <ufs/ffs/fs.h>
43 
44 #include <err.h>
45 #include <inttypes.h>
46 #include <limits.h>
47 #include <string.h>
48 #include <libufs.h>
49 
50 #include "fsck.h"
51 
52 static void check_maps(u_char *, u_char *, int, ufs2_daddr_t, const char *,
53 			int *, int, int, int);
54 static void clear_blocks(ufs2_daddr_t start, ufs2_daddr_t end);
55 
56 void
57 pass5(void)
58 {
59 	int c, i, j, blk, frags, basesize, mapsize;
60 	int inomapsize, blkmapsize;
61 	struct fs *fs = &sblock;
62 	ufs2_daddr_t d, dbase, dmax, start;
63 	int rewritecg = 0;
64 	struct csum *cs;
65 	struct csum_total cstotal;
66 	struct inodesc idesc[3];
67 	char buf[MAXBSIZE];
68 	struct cg *cg, *newcg = (struct cg *)buf;
69 	struct bufarea *cgbp;
70 
71 	inoinfo(WINO)->ino_state = USTATE;
72 	memset(newcg, 0, (size_t)fs->fs_cgsize);
73 	newcg->cg_niblk = fs->fs_ipg;
74 	if (cvtlevel >= 3) {
75 		if (fs->fs_maxcontig < 2 && fs->fs_contigsumsize > 0) {
76 			if (preen)
77 				pwarn("DELETING CLUSTERING MAPS\n");
78 			if (preen || reply("DELETE CLUSTERING MAPS")) {
79 				fs->fs_contigsumsize = 0;
80 				rewritecg = 1;
81 				sbdirty();
82 			}
83 		}
84 		if (fs->fs_maxcontig > 1) {
85 			const char *doit = 0;
86 
87 			if (fs->fs_contigsumsize < 1) {
88 				doit = "CREAT";
89 			} else if (fs->fs_contigsumsize < fs->fs_maxcontig &&
90 				   fs->fs_contigsumsize < FS_MAXCONTIG) {
91 				doit = "EXPAND";
92 			}
93 			if (doit) {
94 				i = fs->fs_contigsumsize;
95 				fs->fs_contigsumsize =
96 				    MIN(fs->fs_maxcontig, FS_MAXCONTIG);
97 				if (CGSIZE(fs) > (u_int)fs->fs_bsize) {
98 					pwarn("CANNOT %s CLUSTER MAPS\n", doit);
99 					fs->fs_contigsumsize = i;
100 				} else if (preen ||
101 				    reply("CREATE CLUSTER MAPS")) {
102 					if (preen)
103 						pwarn("%sING CLUSTER MAPS\n",
104 						    doit);
105 					fs->fs_cgsize =
106 					    fragroundup(fs, CGSIZE(fs));
107 					rewritecg = 1;
108 					sbdirty();
109 				}
110 			}
111 		}
112 	}
113 	basesize = &newcg->cg_space[0] - (u_char *)(&newcg->cg_firstfield);
114 	if (sblock.fs_magic == FS_UFS2_MAGIC) {
115 		newcg->cg_iusedoff = basesize;
116 	} else {
117 		/*
118 		 * We reserve the space for the old rotation summary
119 		 * tables for the benefit of old kernels, but do not
120 		 * maintain them in modern kernels. In time, they can
121 		 * go away.
122 		 */
123 		newcg->cg_old_btotoff = basesize;
124 		newcg->cg_old_boff = newcg->cg_old_btotoff +
125 		    fs->fs_old_cpg * sizeof(int32_t);
126 		newcg->cg_iusedoff = newcg->cg_old_boff +
127 		    fs->fs_old_cpg * fs->fs_old_nrpos * sizeof(u_int16_t);
128 		memset(&newcg->cg_space[0], 0, newcg->cg_iusedoff - basesize);
129 	}
130 	inomapsize = howmany(fs->fs_ipg, CHAR_BIT);
131 	newcg->cg_freeoff = newcg->cg_iusedoff + inomapsize;
132 	blkmapsize = howmany(fs->fs_fpg, CHAR_BIT);
133 	newcg->cg_nextfreeoff = newcg->cg_freeoff + blkmapsize;
134 	if (fs->fs_contigsumsize > 0) {
135 		newcg->cg_clustersumoff = newcg->cg_nextfreeoff -
136 		    sizeof(u_int32_t);
137 		newcg->cg_clustersumoff =
138 		    roundup(newcg->cg_clustersumoff, sizeof(u_int32_t));
139 		newcg->cg_clusteroff = newcg->cg_clustersumoff +
140 		    (fs->fs_contigsumsize + 1) * sizeof(u_int32_t);
141 		newcg->cg_nextfreeoff = newcg->cg_clusteroff +
142 		    howmany(fragstoblks(fs, fs->fs_fpg), CHAR_BIT);
143 	}
144 	newcg->cg_magic = CG_MAGIC;
145 	mapsize = newcg->cg_nextfreeoff - newcg->cg_iusedoff;
146 	memset(&idesc[0], 0, sizeof idesc);
147 	for (i = 0; i < 3; i++)
148 		idesc[i].id_type = ADDR;
149 	memset(&cstotal, 0, sizeof(struct csum_total));
150 	dmax = blknum(fs, fs->fs_size + fs->fs_frag - 1);
151 	for (d = fs->fs_size; d < dmax; d++)
152 		setbmap(d);
153 	for (c = 0; c < fs->fs_ncg; c++) {
154 		if (got_siginfo) {
155 			printf("%s: phase 5: cyl group %d of %d (%d%%)\n",
156 			    cdevname, c, sblock.fs_ncg,
157 			    c * 100 / sblock.fs_ncg);
158 			got_siginfo = 0;
159 		}
160 		if (got_sigalarm) {
161 			setproctitle("%s p5 %d%%", cdevname,
162 			    c * 100 / sblock.fs_ncg);
163 			got_sigalarm = 0;
164 		}
165 		cgbp = cgget(c);
166 		cg = cgbp->b_un.b_cg;
167 		if (!cg_chkmagic(cg))
168 			pfatal("CG %d: BAD MAGIC NUMBER\n", c);
169 		newcg->cg_time = cg->cg_time;
170 		newcg->cg_old_time = cg->cg_old_time;
171 		newcg->cg_unrefs = cg->cg_unrefs;
172 		newcg->cg_cgx = c;
173 		dbase = cgbase(fs, c);
174 		dmax = dbase + fs->fs_fpg;
175 		if (dmax > fs->fs_size)
176 			dmax = fs->fs_size;
177 		newcg->cg_ndblk = dmax - dbase;
178 		if (fs->fs_magic == FS_UFS1_MAGIC) {
179 			if (c == fs->fs_ncg - 1)
180 				newcg->cg_old_ncyl = howmany(newcg->cg_ndblk,
181 				    fs->fs_fpg / fs->fs_old_cpg);
182 			else
183 				newcg->cg_old_ncyl = fs->fs_old_cpg;
184 			newcg->cg_old_niblk = fs->fs_ipg;
185 			newcg->cg_niblk = 0;
186 		}
187 		if (fs->fs_contigsumsize > 0)
188 			newcg->cg_nclusterblks = newcg->cg_ndblk / fs->fs_frag;
189 		newcg->cg_cs.cs_ndir = 0;
190 		newcg->cg_cs.cs_nffree = 0;
191 		newcg->cg_cs.cs_nbfree = 0;
192 		newcg->cg_cs.cs_nifree = fs->fs_ipg;
193 		if (cg->cg_rotor >= 0 && cg->cg_rotor < newcg->cg_ndblk)
194 			newcg->cg_rotor = cg->cg_rotor;
195 		else
196 			newcg->cg_rotor = 0;
197 		if (cg->cg_frotor >= 0 && cg->cg_frotor < newcg->cg_ndblk)
198 			newcg->cg_frotor = cg->cg_frotor;
199 		else
200 			newcg->cg_frotor = 0;
201 		if (cg->cg_irotor >= 0 && cg->cg_irotor < fs->fs_ipg)
202 			newcg->cg_irotor = cg->cg_irotor;
203 		else
204 			newcg->cg_irotor = 0;
205 		if (fs->fs_magic == FS_UFS1_MAGIC) {
206 			newcg->cg_initediblk = 0;
207 		} else {
208 			if ((unsigned)cg->cg_initediblk > fs->fs_ipg)
209 				newcg->cg_initediblk = fs->fs_ipg;
210 			else
211 				newcg->cg_initediblk = cg->cg_initediblk;
212 		}
213 		memset(&newcg->cg_frsum[0], 0, sizeof newcg->cg_frsum);
214 		memset(cg_inosused(newcg), 0, (size_t)(mapsize));
215 		j = fs->fs_ipg * c;
216 		for (i = 0; i < inostathead[c].il_numalloced; j++, i++) {
217 			switch (inoinfo(j)->ino_state) {
218 
219 			case USTATE:
220 				break;
221 
222 			case DSTATE:
223 			case DCLEAR:
224 			case DFOUND:
225 			case DZLINK:
226 				newcg->cg_cs.cs_ndir++;
227 				/* FALLTHROUGH */
228 
229 			case FSTATE:
230 			case FCLEAR:
231 			case FZLINK:
232 				newcg->cg_cs.cs_nifree--;
233 				setbit(cg_inosused(newcg), i);
234 				break;
235 
236 			default:
237 				if (j < (int)ROOTINO)
238 					break;
239 				errx(EEXIT, "BAD STATE %d FOR INODE I=%d",
240 				    inoinfo(j)->ino_state, j);
241 			}
242 		}
243 		if (c == 0)
244 			for (i = 0; i < (int)ROOTINO; i++) {
245 				setbit(cg_inosused(newcg), i);
246 				newcg->cg_cs.cs_nifree--;
247 			}
248 		start = -1;
249 		for (i = 0, d = dbase;
250 		     d < dmax;
251 		     d += fs->fs_frag, i += fs->fs_frag) {
252 			frags = 0;
253 			for (j = 0; j < fs->fs_frag; j++) {
254 				if (testbmap(d + j)) {
255 					if ((Eflag || Zflag) && start != -1) {
256 						clear_blocks(start, d + j - 1);
257 						start = -1;
258 					}
259 					continue;
260 				}
261 				if (start == -1)
262 					start = d + j;
263 				setbit(cg_blksfree(newcg), i + j);
264 				frags++;
265 			}
266 			if (frags == fs->fs_frag) {
267 				newcg->cg_cs.cs_nbfree++;
268 				if (fs->fs_contigsumsize > 0)
269 					setbit(cg_clustersfree(newcg),
270 					    i / fs->fs_frag);
271 			} else if (frags > 0) {
272 				newcg->cg_cs.cs_nffree += frags;
273 				blk = blkmap(fs, cg_blksfree(newcg), i);
274 				ffs_fragacct(fs, blk, newcg->cg_frsum, 1);
275 			}
276 		}
277 		if ((Eflag || Zflag) && start != -1)
278 			clear_blocks(start, d - 1);
279 		if (fs->fs_contigsumsize > 0) {
280 			int32_t *sump = cg_clustersum(newcg);
281 			u_char *mapp = cg_clustersfree(newcg);
282 			int map = *mapp++;
283 			int bit = 1;
284 			int run = 0;
285 
286 			for (i = 0; i < newcg->cg_nclusterblks; i++) {
287 				if ((map & bit) != 0) {
288 					run++;
289 				} else if (run != 0) {
290 					if (run > fs->fs_contigsumsize)
291 						run = fs->fs_contigsumsize;
292 					sump[run]++;
293 					run = 0;
294 				}
295 				if ((i & (CHAR_BIT - 1)) != (CHAR_BIT - 1)) {
296 					bit <<= 1;
297 				} else {
298 					map = *mapp++;
299 					bit = 1;
300 				}
301 			}
302 			if (run != 0) {
303 				if (run > fs->fs_contigsumsize)
304 					run = fs->fs_contigsumsize;
305 				sump[run]++;
306 			}
307 		}
308 		if (bkgrdflag != 0) {
309 			cstotal.cs_nffree += cg->cg_cs.cs_nffree;
310 			cstotal.cs_nbfree += cg->cg_cs.cs_nbfree;
311 			cstotal.cs_nifree += cg->cg_cs.cs_nifree;
312 			cstotal.cs_ndir += cg->cg_cs.cs_ndir;
313 		} else {
314 			cstotal.cs_nffree += newcg->cg_cs.cs_nffree;
315 			cstotal.cs_nbfree += newcg->cg_cs.cs_nbfree;
316 			cstotal.cs_nifree += newcg->cg_cs.cs_nifree;
317 			cstotal.cs_ndir += newcg->cg_cs.cs_ndir;
318 		}
319 		cs = &fs->fs_cs(fs, c);
320 		if (cursnapshot == 0 &&
321 		    memcmp(&newcg->cg_cs, cs, sizeof *cs) != 0 &&
322 		    dofix(&idesc[0], "FREE BLK COUNT(S) WRONG IN SUPERBLK")) {
323 			memmove(cs, &newcg->cg_cs, sizeof *cs);
324 			sbdirty();
325 		}
326 		if (rewritecg) {
327 			memmove(cg, newcg, (size_t)fs->fs_cgsize);
328 			dirty(cgbp);
329 			continue;
330 		}
331 		if (cursnapshot == 0 &&
332 		    memcmp(newcg, cg, basesize) != 0 &&
333 		    dofix(&idesc[2], "SUMMARY INFORMATION BAD")) {
334 			memmove(cg, newcg, (size_t)basesize);
335 			dirty(cgbp);
336 		}
337 		if (bkgrdflag != 0 || usedsoftdep || debug)
338 			update_maps(cg, newcg, bkgrdflag);
339 		if (cursnapshot == 0 &&
340 		    memcmp(cg_inosused(newcg), cg_inosused(cg), mapsize) != 0 &&
341 		    dofix(&idesc[1], "BLK(S) MISSING IN BIT MAPS")) {
342 			memmove(cg_inosused(cg), cg_inosused(newcg),
343 			      (size_t)mapsize);
344 			dirty(cgbp);
345 		}
346 	}
347 	if (cursnapshot == 0 &&
348 	    memcmp(&cstotal, &fs->fs_cstotal, sizeof cstotal) != 0
349 	    && dofix(&idesc[0], "SUMMARY BLK COUNT(S) WRONG IN SUPERBLK")) {
350 		memmove(&fs->fs_cstotal, &cstotal, sizeof cstotal);
351 		fs->fs_ronly = 0;
352 		fs->fs_fmod = 0;
353 		sbdirty();
354 	}
355 
356 	/*
357 	 * When doing background fsck on a snapshot, figure out whether
358 	 * the superblock summary is inaccurate and correct it when
359 	 * necessary.
360 	 */
361 	if (cursnapshot != 0) {
362 		cmd.size = 1;
363 
364 		cmd.value = cstotal.cs_ndir - fs->fs_cstotal.cs_ndir;
365 		if (cmd.value != 0) {
366 			if (debug)
367 				printf("adjndir by %+" PRIi64 "\n", cmd.value);
368 			if (bkgrdsumadj == 0 || sysctl(adjndir, MIBSIZE, 0, 0,
369 			    &cmd, sizeof cmd) == -1)
370 				rwerror("ADJUST NUMBER OF DIRECTORIES", cmd.value);
371 		}
372 
373 		cmd.value = cstotal.cs_nbfree - fs->fs_cstotal.cs_nbfree;
374 		if (cmd.value != 0) {
375 			if (debug)
376 				printf("adjnbfree by %+" PRIi64 "\n", cmd.value);
377 			if (bkgrdsumadj == 0 || sysctl(adjnbfree, MIBSIZE, 0, 0,
378 			    &cmd, sizeof cmd) == -1)
379 				rwerror("ADJUST NUMBER OF FREE BLOCKS", cmd.value);
380 		}
381 
382 		cmd.value = cstotal.cs_nifree - fs->fs_cstotal.cs_nifree;
383 		if (cmd.value != 0) {
384 			if (debug)
385 				printf("adjnifree by %+" PRIi64 "\n", cmd.value);
386 			if (bkgrdsumadj == 0 || sysctl(adjnifree, MIBSIZE, 0, 0,
387 			    &cmd, sizeof cmd) == -1)
388 				rwerror("ADJUST NUMBER OF FREE INODES", cmd.value);
389 		}
390 
391 		cmd.value = cstotal.cs_nffree - fs->fs_cstotal.cs_nffree;
392 		if (cmd.value != 0) {
393 			if (debug)
394 				printf("adjnffree by %+" PRIi64 "\n", cmd.value);
395 			if (bkgrdsumadj == 0 || sysctl(adjnffree, MIBSIZE, 0, 0,
396 			    &cmd, sizeof cmd) == -1)
397 				rwerror("ADJUST NUMBER OF FREE FRAGS", cmd.value);
398 		}
399 
400 		cmd.value = cstotal.cs_numclusters - fs->fs_cstotal.cs_numclusters;
401 		if (cmd.value != 0) {
402 			if (debug)
403 				printf("adjnumclusters by %+" PRIi64 "\n", cmd.value);
404 			if (bkgrdsumadj == 0 || sysctl(adjnumclusters, MIBSIZE, 0, 0,
405 			    &cmd, sizeof cmd) == -1)
406 				rwerror("ADJUST NUMBER OF FREE CLUSTERS", cmd.value);
407 		}
408 	}
409 }
410 
411 /*
412  * Compare the original cylinder group inode and block bitmaps with the
413  * updated cylinder group inode and block bitmaps. Free inodes and blocks
414  * that have been added. Complain if any previously freed inodes blocks
415  * are now allocated.
416  */
417 void
418 update_maps(
419 	struct cg *oldcg,	/* cylinder group of claimed allocations */
420 	struct cg *newcg,	/* cylinder group of determined allocations */
421 	int usesysctl)		/* 1 => use sysctl interface to update maps */
422 {
423 	int inomapsize, excessdirs;
424 	struct fs *fs = &sblock;
425 
426 	inomapsize = howmany(fs->fs_ipg, CHAR_BIT);
427 	excessdirs = oldcg->cg_cs.cs_ndir - newcg->cg_cs.cs_ndir;
428 	if (excessdirs < 0) {
429 		pfatal("LOST %d DIRECTORIES\n", -excessdirs);
430 		excessdirs = 0;
431 	}
432 	if (excessdirs > 0)
433 		check_maps(cg_inosused(newcg), cg_inosused(oldcg), inomapsize,
434 		    oldcg->cg_cgx * (ufs2_daddr_t)fs->fs_ipg, "DIR", freedirs,
435 		    0, excessdirs, usesysctl);
436 	check_maps(cg_inosused(newcg), cg_inosused(oldcg), inomapsize,
437 	    oldcg->cg_cgx * (ufs2_daddr_t)fs->fs_ipg, "FILE", freefiles,
438 	    excessdirs, fs->fs_ipg, usesysctl);
439 	check_maps(cg_blksfree(oldcg), cg_blksfree(newcg),
440 	    howmany(fs->fs_fpg, CHAR_BIT),
441 	    oldcg->cg_cgx * (ufs2_daddr_t)fs->fs_fpg, "FRAG",
442 	    freeblks, 0, fs->fs_fpg, usesysctl);
443 }
444 
445 static void
446 check_maps(
447 	u_char *map1,	/* map of claimed allocations */
448 	u_char *map2,	/* map of determined allocations */
449 	int mapsize,	/* size of above two maps */
450 	ufs2_daddr_t startvalue, /* resource value for first element in map */
451 	const char *name,	/* name of resource found in maps */
452 	int *opcode,	/* sysctl opcode to free resource */
453 	int skip,	/* number of entries to skip before starting to free */
454 	int limit,	/* limit on number of entries to free */
455 	int usesysctl)	/* 1 => use sysctl interface to update maps */
456 {
457 #	define BUFSIZE 16
458 	char buf[BUFSIZE];
459 	long i, j, k, l, m, size;
460 	ufs2_daddr_t n, astart, aend, ustart, uend;
461 	void (*msg)(const char *fmt, ...);
462 
463 	if (usesysctl)
464 		msg = pfatal;
465 	else
466 		msg = pwarn;
467 	astart = ustart = aend = uend = -1;
468 	for (i = 0; i < mapsize; i++) {
469 		j = *map1++;
470 		k = *map2++;
471 		if (j == k)
472 			continue;
473 		for (m = 0, l = 1; m < CHAR_BIT; m++, l <<= 1) {
474 			if ((j & l) == (k & l))
475 				continue;
476 			n = startvalue + i * CHAR_BIT + m;
477 			if ((j & l) != 0) {
478 				if (astart == -1) {
479 					astart = aend = n;
480 					continue;
481 				}
482 				if (aend + 1 == n) {
483 					aend = n;
484 					continue;
485 				}
486 				if (astart == aend)
487 					(*msg)("ALLOCATED %s %" PRId64
488 					    " MARKED FREE\n",
489 					    name, astart);
490 				else
491 					(*msg)("%s %sS %" PRId64 "-%" PRId64
492 					    " MARKED FREE\n",
493 					    "ALLOCATED", name, astart, aend);
494 				astart = aend = n;
495 			} else {
496 				if (ustart == -1) {
497 					ustart = uend = n;
498 					continue;
499 				}
500 				if (uend + 1 == n) {
501 					uend = n;
502 					continue;
503 				}
504 				size = uend - ustart + 1;
505 				if (size <= skip) {
506 					skip -= size;
507 					ustart = uend = n;
508 					continue;
509 				}
510 				if (skip > 0) {
511 					ustart += skip;
512 					size -= skip;
513 					skip = 0;
514 				}
515 				if (size > limit)
516 					size = limit;
517 				if (debug && size == 1)
518 					pwarn("%s %s %" PRId64
519 					    " MARKED USED\n",
520 					    "UNALLOCATED", name, ustart);
521 				else if (debug)
522 					pwarn("%s %sS %" PRId64 "-%" PRId64
523 					    " MARKED USED\n",
524 					    "UNALLOCATED", name, ustart,
525 					    ustart + size - 1);
526 				if (usesysctl != 0) {
527 					cmd.value = ustart;
528 					cmd.size = size;
529 					if (sysctl(opcode, MIBSIZE, 0, 0,
530 					    &cmd, sizeof cmd) == -1) {
531 						snprintf(buf, BUFSIZE,
532 						    "FREE %s", name);
533 						rwerror(buf, cmd.value);
534 					}
535 				}
536 				limit -= size;
537 				if (limit <= 0)
538 					return;
539 				ustart = uend = n;
540 			}
541 		}
542 	}
543 	if (astart != -1) {
544 		if (astart == aend)
545 			(*msg)("ALLOCATED %s %" PRId64
546 			    " MARKED FREE\n", name, astart);
547 		else
548 			(*msg)("ALLOCATED %sS %" PRId64 "-%" PRId64
549 			    " MARKED FREE\n",
550 			    name, astart, aend);
551 	}
552 	if (ustart != -1) {
553 		size = uend - ustart + 1;
554 		if (size <= skip)
555 			return;
556 		if (skip > 0) {
557 			ustart += skip;
558 			size -= skip;
559 		}
560 		if (size > limit)
561 			size = limit;
562 		if (debug) {
563 			if (size == 1)
564 				pwarn("UNALLOCATED %s %" PRId64
565 				    " MARKED USED\n",
566 				    name, ustart);
567 			else
568 				pwarn("UNALLOCATED %sS %" PRId64 "-%" PRId64
569 				    " MARKED USED\n",
570 				    name, ustart, ustart + size - 1);
571 		}
572 		if (usesysctl != 0) {
573 			cmd.value = ustart;
574 			cmd.size = size;
575 			if (sysctl(opcode, MIBSIZE, 0, 0, &cmd,
576 			    sizeof cmd) == -1) {
577 				snprintf(buf, BUFSIZE, "FREE %s", name);
578 				rwerror(buf, cmd.value);
579 			}
580 		}
581 	}
582 }
583 
584 static void
585 clear_blocks(ufs2_daddr_t start, ufs2_daddr_t end)
586 {
587 
588 	if (debug)
589 		printf("Zero frags %jd to %jd\n", start, end);
590 	if (Zflag)
591 		blzero(fswritefd, fsbtodb(&sblock, start),
592 		    lfragtosize(&sblock, end - start + 1));
593 	if (Eflag)
594 		blerase(fswritefd, fsbtodb(&sblock, start),
595 		    lfragtosize(&sblock, end - start + 1));
596 }
597