xref: /freebsd/sbin/fsck_ffs/pass5.c (revision 772430dd67955850942d689714ab982da24257ba)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 1986, 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 
32 #if 0
33 #ifndef lint
34 static const char sccsid[] = "@(#)pass5.c	8.9 (Berkeley) 4/28/95";
35 #endif /* not lint */
36 #endif
37 #include <sys/cdefs.h>
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 
49 #include "fsck.h"
50 
51 static void check_maps(u_char *, u_char *, int, ufs2_daddr_t, const char *,
52 			int *, int, int, int);
53 static void clear_blocks(ufs2_daddr_t start, ufs2_daddr_t end);
54 
55 void
56 pass5(void)
57 {
58 	int c, i, j, blk, frags, basesize, mapsize;
59 	int inomapsize, blkmapsize;
60 	struct fs *fs = &sblock;
61 	ufs2_daddr_t d, dbase, dmax, start;
62 	int rewritecg = 0;
63 	ino_t inum;
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(UFS_WINO)->ino_state = USTATE;
72 	memset(newcg, 0, (size_t)fs->fs_cgsize);
73 	newcg->cg_niblk = fs->fs_ipg;
74 	/* check to see if we are to add a cylinder group check hash */
75 	if ((ckhashadd & CK_CYLGRP) != 0)
76 		rewritecg = 1;
77 	if (cvtlevel >= 3) {
78 		if (fs->fs_maxcontig < 2 && fs->fs_contigsumsize > 0) {
79 			if (preen)
80 				pwarn("DELETING CLUSTERING MAPS\n");
81 			if (preen || reply("DELETE CLUSTERING MAPS")) {
82 				fs->fs_contigsumsize = 0;
83 				rewritecg = 1;
84 				sbdirty();
85 			}
86 		}
87 		if (fs->fs_maxcontig > 1) {
88 			const char *doit = NULL;
89 
90 			if (fs->fs_contigsumsize < 1) {
91 				doit = "CREAT";
92 			} else if (fs->fs_contigsumsize < fs->fs_maxcontig &&
93 				   fs->fs_contigsumsize < FS_MAXCONTIG) {
94 				doit = "EXPAND";
95 			}
96 			if (doit) {
97 				i = fs->fs_contigsumsize;
98 				fs->fs_contigsumsize =
99 				    MIN(fs->fs_maxcontig, FS_MAXCONTIG);
100 				if (CGSIZE(fs) > (u_int)fs->fs_bsize) {
101 					pwarn("CANNOT %s CLUSTER MAPS\n", doit);
102 					fs->fs_contigsumsize = i;
103 				} else if (preen ||
104 				    reply("CREATE CLUSTER MAPS")) {
105 					if (preen)
106 						pwarn("%sING CLUSTER MAPS\n",
107 						    doit);
108 					fs->fs_cgsize =
109 					    fragroundup(fs, CGSIZE(fs));
110 					rewritecg = 1;
111 					sbdirty();
112 				}
113 			}
114 		}
115 	}
116 	basesize = sizeof(*newcg);
117 	if (sblock.fs_magic == FS_UFS2_MAGIC) {
118 		newcg->cg_iusedoff = basesize;
119 	} else {
120 		/*
121 		 * We reserve the space for the old rotation summary
122 		 * tables for the benefit of old kernels, but do not
123 		 * maintain them in modern kernels. In time, they can
124 		 * go away.
125 		 */
126 		newcg->cg_old_btotoff = basesize;
127 		newcg->cg_old_boff = newcg->cg_old_btotoff +
128 		    fs->fs_old_cpg * sizeof(int32_t);
129 		newcg->cg_iusedoff = newcg->cg_old_boff +
130 		    fs->fs_old_cpg * fs->fs_old_nrpos * sizeof(u_int16_t);
131 		memset(&newcg[1], 0, newcg->cg_iusedoff - basesize);
132 	}
133 	inomapsize = howmany(fs->fs_ipg, CHAR_BIT);
134 	newcg->cg_freeoff = newcg->cg_iusedoff + inomapsize;
135 	blkmapsize = howmany(fs->fs_fpg, CHAR_BIT);
136 	newcg->cg_nextfreeoff = newcg->cg_freeoff + blkmapsize;
137 	if (fs->fs_contigsumsize > 0) {
138 		newcg->cg_clustersumoff = newcg->cg_nextfreeoff -
139 		    sizeof(u_int32_t);
140 		newcg->cg_clustersumoff =
141 		    roundup(newcg->cg_clustersumoff, sizeof(u_int32_t));
142 		newcg->cg_clusteroff = newcg->cg_clustersumoff +
143 		    (fs->fs_contigsumsize + 1) * sizeof(u_int32_t);
144 		newcg->cg_nextfreeoff = newcg->cg_clusteroff +
145 		    howmany(fragstoblks(fs, fs->fs_fpg), CHAR_BIT);
146 	}
147 	newcg->cg_magic = CG_MAGIC;
148 	mapsize = newcg->cg_nextfreeoff - newcg->cg_iusedoff;
149 	memset(&idesc[0], 0, sizeof idesc);
150 	for (i = 0; i < 3; i++)
151 		idesc[i].id_type = ADDR;
152 	memset(&cstotal, 0, sizeof(struct csum_total));
153 	dmax = blknum(fs, fs->fs_size + fs->fs_frag - 1);
154 	for (d = fs->fs_size; d < dmax; d++)
155 		setbmap(d);
156 	for (c = 0; c < fs->fs_ncg; c++) {
157 		if (got_siginfo) {
158 			printf("%s: phase 5: cyl group %d of %d (%d%%)\n",
159 			    cdevname, c, sblock.fs_ncg,
160 			    c * 100 / sblock.fs_ncg);
161 			got_siginfo = 0;
162 		}
163 		if (got_sigalarm) {
164 			setproctitle("%s p5 %d%%", cdevname,
165 			    c * 100 / sblock.fs_ncg);
166 			got_sigalarm = 0;
167 		}
168 		cgbp = cglookup(c);
169 		cg = cgbp->b_un.b_cg;
170 		if (!cg_chkmagic(cg))
171 			pfatal("CG %d: BAD MAGIC NUMBER\n", c);
172 		/*
173 		 * If we have a cylinder group check hash and are not adding
174 		 * it for the first time, verify that it is good.
175 		 */
176 		if ((fs->fs_metackhash & CK_CYLGRP) != 0 &&
177 		    (ckhashadd & CK_CYLGRP) == 0) {
178 			uint32_t ckhash, thishash;
179 
180 			ckhash = cg->cg_ckhash;
181 			cg->cg_ckhash = 0;
182 			thishash = calculate_crc32c(~0L, cg, fs->fs_cgsize);
183 			if (ckhash == thishash) {
184 				cg->cg_ckhash = ckhash;
185 			} else {
186 				pwarn("CG %d: BAD CHECK-HASH %#x vs %#x\n",
187 				    c, ckhash, thishash);
188 				cg->cg_ckhash = thishash;
189 				cgdirty(cgbp);
190 			}
191 		}
192 		newcg->cg_time = cg->cg_time;
193 		newcg->cg_old_time = cg->cg_old_time;
194 		newcg->cg_unrefs = cg->cg_unrefs;
195 		newcg->cg_ckhash = cg->cg_ckhash;
196 		newcg->cg_cgx = c;
197 		dbase = cgbase(fs, c);
198 		dmax = dbase + fs->fs_fpg;
199 		if (dmax > fs->fs_size)
200 			dmax = fs->fs_size;
201 		newcg->cg_ndblk = dmax - dbase;
202 		if (fs->fs_magic == FS_UFS1_MAGIC) {
203 			if (c == fs->fs_ncg - 1)
204 				newcg->cg_old_ncyl = howmany(newcg->cg_ndblk,
205 				    fs->fs_fpg / fs->fs_old_cpg);
206 			else
207 				newcg->cg_old_ncyl = fs->fs_old_cpg;
208 			newcg->cg_old_niblk = fs->fs_ipg;
209 			newcg->cg_niblk = 0;
210 		}
211 		if (fs->fs_contigsumsize > 0)
212 			newcg->cg_nclusterblks = newcg->cg_ndblk / fs->fs_frag;
213 		newcg->cg_cs.cs_ndir = 0;
214 		newcg->cg_cs.cs_nffree = 0;
215 		newcg->cg_cs.cs_nbfree = 0;
216 		newcg->cg_cs.cs_nifree = fs->fs_ipg;
217 		if (cg->cg_rotor >= 0 && cg->cg_rotor < newcg->cg_ndblk)
218 			newcg->cg_rotor = cg->cg_rotor;
219 		else
220 			newcg->cg_rotor = 0;
221 		if (cg->cg_frotor >= 0 && cg->cg_frotor < newcg->cg_ndblk)
222 			newcg->cg_frotor = cg->cg_frotor;
223 		else
224 			newcg->cg_frotor = 0;
225 		if (cg->cg_irotor >= 0 && cg->cg_irotor < fs->fs_ipg)
226 			newcg->cg_irotor = cg->cg_irotor;
227 		else
228 			newcg->cg_irotor = 0;
229 		if (fs->fs_magic == FS_UFS1_MAGIC) {
230 			newcg->cg_initediblk = 0;
231 		} else {
232 			if ((unsigned)cg->cg_initediblk > fs->fs_ipg)
233 				newcg->cg_initediblk = fs->fs_ipg;
234 			else
235 				newcg->cg_initediblk = cg->cg_initediblk;
236 		}
237 		memset(&newcg->cg_frsum[0], 0, sizeof newcg->cg_frsum);
238 		memset(cg_inosused(newcg), 0, (size_t)(mapsize));
239 		inum = fs->fs_ipg * c;
240 		for (i = 0; i < inostathead[c].il_numalloced; inum++, i++) {
241 			switch (inoinfo(inum)->ino_state) {
242 
243 			case USTATE:
244 				break;
245 
246 			case DSTATE:
247 			case DCLEAR:
248 			case DFOUND:
249 			case DZLINK:
250 				newcg->cg_cs.cs_ndir++;
251 				/* FALLTHROUGH */
252 
253 			case FSTATE:
254 			case FCLEAR:
255 			case FZLINK:
256 				newcg->cg_cs.cs_nifree--;
257 				setbit(cg_inosused(newcg), i);
258 				break;
259 
260 			default:
261 				if (inum < UFS_ROOTINO)
262 					break;
263 				errx(EEXIT, "BAD STATE %d FOR INODE I=%ju",
264 				    inoinfo(inum)->ino_state, (uintmax_t)inum);
265 			}
266 		}
267 		if (c == 0)
268 			for (i = 0; i < (int)UFS_ROOTINO; i++) {
269 				setbit(cg_inosused(newcg), i);
270 				newcg->cg_cs.cs_nifree--;
271 			}
272 		start = -1;
273 		for (i = 0, d = dbase;
274 		     d < dmax;
275 		     d += fs->fs_frag, i += fs->fs_frag) {
276 			frags = 0;
277 			for (j = 0; j < fs->fs_frag; j++) {
278 				if (testbmap(d + j)) {
279 					if ((Eflag || Zflag) && start != -1) {
280 						clear_blocks(start, d + j - 1);
281 						start = -1;
282 					}
283 					continue;
284 				}
285 				if (start == -1)
286 					start = d + j;
287 				setbit(cg_blksfree(newcg), i + j);
288 				frags++;
289 			}
290 			if (frags == fs->fs_frag) {
291 				newcg->cg_cs.cs_nbfree++;
292 				if (fs->fs_contigsumsize > 0)
293 					setbit(cg_clustersfree(newcg),
294 					    i / fs->fs_frag);
295 			} else if (frags > 0) {
296 				newcg->cg_cs.cs_nffree += frags;
297 				blk = blkmap(fs, cg_blksfree(newcg), i);
298 				ffs_fragacct(fs, blk, newcg->cg_frsum, 1);
299 			}
300 		}
301 		if ((Eflag || Zflag) && start != -1)
302 			clear_blocks(start, d - 1);
303 		if (fs->fs_contigsumsize > 0) {
304 			int32_t *sump = cg_clustersum(newcg);
305 			u_char *mapp = cg_clustersfree(newcg);
306 			int map = *mapp++;
307 			int bit = 1;
308 			int run = 0;
309 
310 			for (i = 0; i < newcg->cg_nclusterblks; i++) {
311 				if ((map & bit) != 0) {
312 					run++;
313 				} else if (run != 0) {
314 					if (run > fs->fs_contigsumsize)
315 						run = fs->fs_contigsumsize;
316 					sump[run]++;
317 					run = 0;
318 				}
319 				if ((i & (CHAR_BIT - 1)) != (CHAR_BIT - 1)) {
320 					bit <<= 1;
321 				} else {
322 					map = *mapp++;
323 					bit = 1;
324 				}
325 			}
326 			if (run != 0) {
327 				if (run > fs->fs_contigsumsize)
328 					run = fs->fs_contigsumsize;
329 				sump[run]++;
330 			}
331 		}
332 
333 		if (bkgrdflag != 0) {
334 			cstotal.cs_nffree += cg->cg_cs.cs_nffree;
335 			cstotal.cs_nbfree += cg->cg_cs.cs_nbfree;
336 			cstotal.cs_nifree += cg->cg_cs.cs_nifree;
337 			cstotal.cs_ndir += cg->cg_cs.cs_ndir;
338 		} else {
339 			cstotal.cs_nffree += newcg->cg_cs.cs_nffree;
340 			cstotal.cs_nbfree += newcg->cg_cs.cs_nbfree;
341 			cstotal.cs_nifree += newcg->cg_cs.cs_nifree;
342 			cstotal.cs_ndir += newcg->cg_cs.cs_ndir;
343 		}
344 		cs = &fs->fs_cs(fs, c);
345 		if (cursnapshot == 0 &&
346 		    memcmp(&newcg->cg_cs, cs, sizeof *cs) != 0 &&
347 		    dofix(&idesc[0], "FREE BLK COUNT(S) WRONG IN SUPERBLK")) {
348 			memmove(cs, &newcg->cg_cs, sizeof *cs);
349 			sbdirty();
350 		}
351 		if (rewritecg) {
352 			memmove(cg, newcg, (size_t)fs->fs_cgsize);
353 			cgdirty(cgbp);
354 			continue;
355 		}
356 		if (cursnapshot == 0 &&
357 		    memcmp(newcg, cg, basesize) != 0 &&
358 		    dofix(&idesc[2], "SUMMARY INFORMATION BAD")) {
359 			memmove(cg, newcg, (size_t)basesize);
360 			cgdirty(cgbp);
361 		}
362 		if (bkgrdflag != 0 || usedsoftdep || debug)
363 			update_maps(cg, newcg, bkgrdflag);
364 		if (cursnapshot == 0 &&
365 		    memcmp(cg_inosused(newcg), cg_inosused(cg), mapsize) != 0 &&
366 		    dofix(&idesc[1], "BLK(S) MISSING IN BIT MAPS")) {
367 			memmove(cg_inosused(cg), cg_inosused(newcg),
368 			      (size_t)mapsize);
369 			cgdirty(cgbp);
370 		}
371 	}
372 	if (cursnapshot == 0 &&
373 	    memcmp(&cstotal, &fs->fs_cstotal, sizeof cstotal) != 0
374 	    && dofix(&idesc[0], "SUMMARY BLK COUNT(S) WRONG IN SUPERBLK")) {
375 		if (debug) {
376 			printf("cstotal is currently: %jd dirs, %jd blks free, "
377 			    "%jd frags free, %jd inos free, %jd clusters\n",
378 			    (intmax_t)fs->fs_cstotal.cs_ndir,
379 			    (intmax_t)fs->fs_cstotal.cs_nbfree,
380 			    (intmax_t)fs->fs_cstotal.cs_nffree,
381 			    (intmax_t)fs->fs_cstotal.cs_nifree,
382 			    (intmax_t)fs->fs_cstotal.cs_numclusters);
383 			printf("cstotal ought to be:  %jd dirs, %jd blks free, "
384 			    "%jd frags free, %jd inos free, %jd clusters\n",
385 			    (intmax_t)cstotal.cs_ndir,
386 			    (intmax_t)cstotal.cs_nbfree,
387 			    (intmax_t)cstotal.cs_nffree,
388 			    (intmax_t)cstotal.cs_nifree,
389 			    (intmax_t)cstotal.cs_numclusters);
390 		}
391 		memmove(&fs->fs_cstotal, &cstotal, sizeof cstotal);
392 		fs->fs_ronly = 0;
393 		fs->fs_fmod = 0;
394 		sbdirty();
395 	}
396 
397 	/*
398 	 * When doing background fsck on a snapshot, figure out whether
399 	 * the superblock summary is inaccurate and correct it when
400 	 * necessary.
401 	 */
402 	if (cursnapshot != 0) {
403 		cmd.size = 1;
404 
405 		cmd.value = cstotal.cs_ndir - fs->fs_cstotal.cs_ndir;
406 		if (cmd.value != 0) {
407 			if (debug)
408 				printf("adjndir by %+" PRIi64 "\n", cmd.value);
409 			if (bkgrdsumadj == 0 || sysctl(adjndir, MIBSIZE, 0, 0,
410 			    &cmd, sizeof cmd) == -1)
411 				rwerror("ADJUST NUMBER OF DIRECTORIES",
412 				    cmd.value);
413 		}
414 
415 		cmd.value = cstotal.cs_nbfree - fs->fs_cstotal.cs_nbfree;
416 		if (cmd.value != 0) {
417 			if (debug)
418 				printf("adjnbfree by %+" PRIi64 "\n",
419 				    cmd.value);
420 			if (bkgrdsumadj == 0 || sysctl(adjnbfree, MIBSIZE, 0, 0,
421 			    &cmd, sizeof cmd) == -1)
422 				rwerror("ADJUST NUMBER OF FREE BLOCKS",
423 				    cmd.value);
424 		}
425 
426 		cmd.value = cstotal.cs_nifree - fs->fs_cstotal.cs_nifree;
427 		if (cmd.value != 0) {
428 			if (debug)
429 				printf("adjnifree by %+" PRIi64 "\n",
430 				    cmd.value);
431 			if (bkgrdsumadj == 0 || sysctl(adjnifree, MIBSIZE, 0, 0,
432 			    &cmd, sizeof cmd) == -1)
433 				rwerror("ADJUST NUMBER OF FREE INODES",
434 				    cmd.value);
435 		}
436 
437 		cmd.value = cstotal.cs_nffree - fs->fs_cstotal.cs_nffree;
438 		if (cmd.value != 0) {
439 			if (debug)
440 				printf("adjnffree by %+" PRIi64 "\n",
441 				    cmd.value);
442 			if (bkgrdsumadj == 0 || sysctl(adjnffree, MIBSIZE, 0, 0,
443 			    &cmd, sizeof cmd) == -1)
444 				rwerror("ADJUST NUMBER OF FREE FRAGS",
445 				    cmd.value);
446 		}
447 
448 		cmd.value = cstotal.cs_numclusters -
449 		    fs->fs_cstotal.cs_numclusters;
450 		if (cmd.value != 0) {
451 			if (debug)
452 				printf("adjnumclusters by %+" PRIi64 "\n",
453 				    cmd.value);
454 			if (bkgrdsumadj == 0 || sysctl(adjnumclusters, MIBSIZE,
455 			    0, 0, &cmd, sizeof cmd) == -1)
456 				rwerror("ADJUST NUMBER OF FREE CLUSTERS",
457 				    cmd.value);
458 		}
459 	}
460 }
461 
462 /*
463  * Compare the original cylinder group inode and block bitmaps with the
464  * updated cylinder group inode and block bitmaps. Free inodes and blocks
465  * that have been added. Complain if any previously freed inodes blocks
466  * are now allocated.
467  */
468 void
469 update_maps(
470 	struct cg *oldcg,	/* cylinder group of claimed allocations */
471 	struct cg *newcg,	/* cylinder group of determined allocations */
472 	int usesysctl)		/* 1 => use sysctl interface to update maps */
473 {
474 	int inomapsize, excessdirs;
475 	struct fs *fs = &sblock;
476 
477 	inomapsize = howmany(fs->fs_ipg, CHAR_BIT);
478 	excessdirs = oldcg->cg_cs.cs_ndir - newcg->cg_cs.cs_ndir;
479 	if (excessdirs < 0) {
480 		pfatal("LOST %d DIRECTORIES\n", -excessdirs);
481 		excessdirs = 0;
482 	}
483 	if (excessdirs > 0)
484 		check_maps(cg_inosused(newcg), cg_inosused(oldcg), inomapsize,
485 		    oldcg->cg_cgx * (ufs2_daddr_t)fs->fs_ipg, "DIR", freedirs,
486 		    0, excessdirs, usesysctl);
487 	check_maps(cg_inosused(newcg), cg_inosused(oldcg), inomapsize,
488 	    oldcg->cg_cgx * (ufs2_daddr_t)fs->fs_ipg, "FILE", freefiles,
489 	    excessdirs, fs->fs_ipg, usesysctl);
490 	check_maps(cg_blksfree(oldcg), cg_blksfree(newcg),
491 	    howmany(fs->fs_fpg, CHAR_BIT),
492 	    oldcg->cg_cgx * (ufs2_daddr_t)fs->fs_fpg, "FRAG",
493 	    freeblks, 0, fs->fs_fpg, usesysctl);
494 }
495 
496 static void
497 check_maps(
498 	u_char *map1,	/* map of claimed allocations */
499 	u_char *map2,	/* map of determined allocations */
500 	int mapsize,	/* size of above two maps */
501 	ufs2_daddr_t startvalue, /* resource value for first element in map */
502 	const char *name,	/* name of resource found in maps */
503 	int *opcode,	/* sysctl opcode to free resource */
504 	int skip,	/* number of entries to skip before starting to free */
505 	int limit,	/* limit on number of entries to free */
506 	int usesysctl)	/* 1 => use sysctl interface to update maps */
507 {
508 #	define BUFSIZE 16
509 	char buf[BUFSIZE];
510 	long i, j, k, l, m, size;
511 	ufs2_daddr_t n, astart, aend, ustart, uend;
512 	void (*msg)(const char *fmt, ...);
513 
514 	if (usesysctl)
515 		msg = pfatal;
516 	else
517 		msg = pwarn;
518 	astart = ustart = aend = uend = -1;
519 	for (i = 0; i < mapsize; i++) {
520 		j = *map1++;
521 		k = *map2++;
522 		if (j == k)
523 			continue;
524 		for (m = 0, l = 1; m < CHAR_BIT; m++, l <<= 1) {
525 			if ((j & l) == (k & l))
526 				continue;
527 			n = startvalue + i * CHAR_BIT + m;
528 			if ((j & l) != 0) {
529 				if (astart == -1) {
530 					astart = aend = n;
531 					continue;
532 				}
533 				if (aend + 1 == n) {
534 					aend = n;
535 					continue;
536 				}
537 				if (astart == aend)
538 					(*msg)("ALLOCATED %s %" PRId64
539 					    " MARKED FREE\n",
540 					    name, astart);
541 				else
542 					(*msg)("%s %sS %" PRId64 "-%" PRId64
543 					    " MARKED FREE\n",
544 					    "ALLOCATED", name, astart, aend);
545 				astart = aend = n;
546 			} else {
547 				if (ustart == -1) {
548 					ustart = uend = n;
549 					continue;
550 				}
551 				if (uend + 1 == n) {
552 					uend = n;
553 					continue;
554 				}
555 				size = uend - ustart + 1;
556 				if (size <= skip) {
557 					skip -= size;
558 					ustart = uend = n;
559 					continue;
560 				}
561 				if (skip > 0) {
562 					ustart += skip;
563 					size -= skip;
564 					skip = 0;
565 				}
566 				if (size > limit)
567 					size = limit;
568 				if (debug && size == 1)
569 					pwarn("%s %s %" PRId64
570 					    " MARKED USED\n",
571 					    "UNALLOCATED", name, ustart);
572 				else if (debug)
573 					pwarn("%s %sS %" PRId64 "-%" PRId64
574 					    " MARKED USED\n",
575 					    "UNALLOCATED", name, ustart,
576 					    ustart + size - 1);
577 				if (usesysctl != 0) {
578 					cmd.value = ustart;
579 					cmd.size = size;
580 					if (sysctl(opcode, MIBSIZE, 0, 0,
581 					    &cmd, sizeof cmd) == -1) {
582 						snprintf(buf, BUFSIZE,
583 						    "FREE %s", name);
584 						rwerror(buf, cmd.value);
585 					}
586 				}
587 				limit -= size;
588 				if (limit <= 0)
589 					return;
590 				ustart = uend = n;
591 			}
592 		}
593 	}
594 	if (astart != -1) {
595 		if (astart == aend)
596 			(*msg)("ALLOCATED %s %" PRId64
597 			    " MARKED FREE\n", name, astart);
598 		else
599 			(*msg)("ALLOCATED %sS %" PRId64 "-%" PRId64
600 			    " MARKED FREE\n",
601 			    name, astart, aend);
602 	}
603 	if (ustart != -1) {
604 		size = uend - ustart + 1;
605 		if (size <= skip)
606 			return;
607 		if (skip > 0) {
608 			ustart += skip;
609 			size -= skip;
610 		}
611 		if (size > limit)
612 			size = limit;
613 		if (debug) {
614 			if (size == 1)
615 				pwarn("UNALLOCATED %s %" PRId64
616 				    " MARKED USED\n",
617 				    name, ustart);
618 			else
619 				pwarn("UNALLOCATED %sS %" PRId64 "-%" PRId64
620 				    " MARKED USED\n",
621 				    name, ustart, ustart + size - 1);
622 		}
623 		if (usesysctl != 0) {
624 			cmd.value = ustart;
625 			cmd.size = size;
626 			if (sysctl(opcode, MIBSIZE, 0, 0, &cmd,
627 			    sizeof cmd) == -1) {
628 				snprintf(buf, BUFSIZE, "FREE %s", name);
629 				rwerror(buf, cmd.value);
630 			}
631 		}
632 	}
633 }
634 
635 static void
636 clear_blocks(ufs2_daddr_t start, ufs2_daddr_t end)
637 {
638 
639 	if (debug)
640 		printf("Zero frags %jd to %jd\n", start, end);
641 	if (Zflag)
642 		blzero(fswritefd, fsbtodb(&sblock, start),
643 		    lfragtosize(&sblock, end - start + 1));
644 	if (Eflag)
645 		blerase(fswritefd, fsbtodb(&sblock, start),
646 		    lfragtosize(&sblock, end - start + 1));
647 }
648