xref: /freebsd/sbin/fsck_ffs/setup.c (revision a2b560cc69eb254c92caf2027a69cadf9865d273)
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[] = "@(#)setup.c	8.10 (Berkeley) 5/9/95";
35 #endif /* not lint */
36 #endif
37 #include <sys/cdefs.h>
38 #include <sys/param.h>
39 #include <sys/disk.h>
40 #include <sys/stat.h>
41 #define FSTYPENAMES
42 #include <sys/disklabel.h>
43 #include <sys/file.h>
44 #include <sys/sysctl.h>
45 
46 #include <ufs/ufs/dinode.h>
47 #include <ufs/ffs/fs.h>
48 
49 #include <ctype.h>
50 #include <err.h>
51 #include <errno.h>
52 #include <limits.h>
53 #include <stdint.h>
54 #include <string.h>
55 
56 #include "fsck.h"
57 
58 struct inohash *inphash;	       /* hash list of directory inode info */
59 struct inoinfo **inpsort;	       /* disk order list of directory inodes */
60 struct inode snaplist[FSMAXSNAP + 1];  /* list of active snapshots */
61 int snapcnt;			       /* number of active snapshots */
62 char *copybuf;			       /* buffer to copy snapshot blocks */
63 
64 static int sbhashfailed;
65 #define POWEROF2(num)	(((num) & ((num) - 1)) == 0)
66 
67 static int calcsb(char *dev, int devfd, struct fs *fs);
68 static void saverecovery(int readfd, int writefd);
69 static int chkrecovery(int devfd);
70 static int getlbnblkno(struct inodesc *);
71 static int checksnapinfo(struct inode *);
72 
73 /*
74  * Read in a superblock finding an alternate if necessary.
75  * Return 1 if successful, 0 if unsuccessful, -1 if file system
76  * is already clean (ckclean and preen mode only).
77  */
78 int
79 setup(char *dev)
80 {
81 	long i, bmapsize;
82 	struct inode ip;
83 
84 	/*
85 	 * We are expected to have an open file descriptor and a superblock.
86 	 */
87 	if (fsreadfd < 0 || havesb == 0) {
88 		if (debug) {
89 			if (fsreadfd < 0)
90 				printf("setup: missing fsreadfd\n");
91 			else
92 				printf("setup: missing superblock\n");
93 		}
94 		return (0);
95 	}
96 	if (preen == 0)
97 		printf("** %s", dev);
98 	if (bkgrdflag == 0 &&
99 	    (nflag || (fswritefd = open(dev, O_WRONLY)) < 0)) {
100 		fswritefd = -1;
101 		if (preen)
102 			pfatal("NO WRITE ACCESS");
103 		printf(" (NO WRITE)");
104 	}
105 	if (preen == 0)
106 		printf("\n");
107 	if (sbhashfailed != 0) {
108 		pwarn("SUPERBLOCK CHECK HASH FAILED");
109 		if (fswritefd == -1)
110 			pwarn("OPENED READONLY SO CANNOT CORRECT CHECK HASH\n");
111 		else if (preen || reply("CORRECT CHECK HASH") != 0) {
112 			if (preen)
113 				printf(" (CORRECTED)\n");
114 			sblock.fs_clean = 0;
115 			sbdirty();
116 		}
117 	}
118 	if (skipclean && ckclean && sblock.fs_clean) {
119 		pwarn("FILE SYSTEM CLEAN; SKIPPING CHECKS\n");
120 		return (-1);
121 	}
122 	maxfsblock = sblock.fs_size;
123 	maxino = sblock.fs_ncg * sblock.fs_ipg;
124 	/*
125 	 * Check and potentially fix certain fields in the super block.
126 	 */
127 	if (sblock.fs_optim != FS_OPTTIME && sblock.fs_optim != FS_OPTSPACE) {
128 		pfatal("UNDEFINED OPTIMIZATION IN SUPERBLOCK");
129 		if (reply("SET TO DEFAULT") == 1) {
130 			sblock.fs_optim = FS_OPTTIME;
131 			sbdirty();
132 		}
133 	}
134 	if ((sblock.fs_minfree < 0 || sblock.fs_minfree > 99)) {
135 		pfatal("IMPOSSIBLE MINFREE=%d IN SUPERBLOCK",
136 			sblock.fs_minfree);
137 		if (reply("SET TO DEFAULT") == 1) {
138 			sblock.fs_minfree = 10;
139 			sbdirty();
140 		}
141 	}
142 	if (sblock.fs_magic == FS_UFS1_MAGIC &&
143 	    sblock.fs_old_inodefmt < FS_44INODEFMT) {
144 		pwarn("Format of file system is too old.\n");
145 		pwarn("Must update to modern format using a version of fsck\n");
146 		pfatal("from before 2002 with the command ``fsck -c 2''\n");
147 		exit(EEXIT);
148 	}
149 	if (preen == 0 && yflag == 0 && sblock.fs_magic == FS_UFS2_MAGIC &&
150 	    fswritefd != -1 && chkrecovery(fsreadfd) == 0 &&
151 	    reply("SAVE DATA TO FIND ALTERNATE SUPERBLOCKS") != 0)
152 		saverecovery(fsreadfd, fswritefd);
153 	/*
154 	 * allocate and initialize the necessary maps
155 	 */
156 	bufinit();
157 	bmapsize = roundup(howmany(maxfsblock, CHAR_BIT), sizeof(short));
158 	blockmap = Calloc((unsigned)bmapsize, sizeof (char));
159 	if (blockmap == NULL) {
160 		printf("cannot alloc %u bytes for blockmap\n",
161 		    (unsigned)bmapsize);
162 		goto badsb;
163 	}
164 	inostathead = Calloc(sblock.fs_ncg, sizeof(struct inostatlist));
165 	if (inostathead == NULL) {
166 		printf("cannot alloc %u bytes for inostathead\n",
167 		    (unsigned)(sizeof(struct inostatlist) * (sblock.fs_ncg)));
168 		goto badsb;
169 	}
170 	numdirs = sblock.fs_cstotal.cs_ndir;
171 	dirhash = MAX(numdirs / 2, 1);
172 	inplast = 0;
173 	listmax = numdirs + 10;
174 	inpsort = (struct inoinfo **)Calloc(listmax, sizeof(struct inoinfo *));
175 	inphash = (struct inohash *)Calloc(dirhash, sizeof(struct inohash));
176 	if (inpsort == NULL || inphash == NULL) {
177 		printf("cannot alloc %ju bytes for inphash\n",
178 		    (uintmax_t)numdirs * sizeof(struct inoinfo *));
179 		goto badsb;
180 	}
181 	if (sblock.fs_flags & FS_DOSOFTDEP)
182 		usedsoftdep = 1;
183 	else
184 		usedsoftdep = 0;
185 	/*
186 	 * Collect any snapshot inodes so that we can allow them to
187 	 * claim any blocks that we free. The code for doing this is
188 	 * imported here and into inode.c from sys/ufs/ffs/ffs_snapshot.c.
189 	 */
190 	for (snapcnt = 0; snapcnt < FSMAXSNAP; snapcnt++) {
191 		if (sblock.fs_snapinum[snapcnt] == 0)
192 			break;
193 		ginode(sblock.fs_snapinum[snapcnt], &ip);
194 		if ((DIP(ip.i_dp, di_mode) & IFMT) == IFREG &&
195 		    (DIP(ip.i_dp, di_flags) & SF_SNAPSHOT) != 0 &&
196 		    checksnapinfo(&ip)) {
197 			if (debug)
198 				printf("Load snapshot %jd\n",
199 				    (intmax_t)sblock.fs_snapinum[snapcnt]);
200 			snaplist[snapcnt] = ip;
201 			continue;
202 		}
203 		printf("Removing non-snapshot inode %ju from snapshot list\n",
204 		    (uintmax_t)sblock.fs_snapinum[snapcnt]);
205 		irelse(&ip);
206 		for (i = snapcnt + 1; i < FSMAXSNAP; i++) {
207 			if (sblock.fs_snapinum[i] == 0)
208 				break;
209 			sblock.fs_snapinum[i - 1] = sblock.fs_snapinum[i];
210 		}
211 		sblock.fs_snapinum[i - 1] = 0;
212 		snapcnt--;
213 		sbdirty();
214 	}
215 	if (snapcnt > 0 && copybuf == NULL) {
216 		copybuf = Balloc(sblock.fs_bsize);
217 		if (copybuf == NULL)
218 			errx(EEXIT, "cannot allocate space for snapshot "
219 			    "copy buffer");
220 	}
221 	return (1);
222 
223 badsb:
224 	ckfini(0);
225 	return (0);
226 }
227 
228 /*
229  * Check for valid snapshot information.
230  *
231  * Each snapshot has a list of blocks that have been copied. This list
232  * is consulted before checking the snapshot inode. Its purpose is to
233  * speed checking of commonly checked blocks and to avoid recursive
234  * checks of the snapshot inode. In particular, the list must contain
235  * the superblock, the superblock summary information, and all the
236  * cylinder group blocks. The list may contain other commonly checked
237  * pointers such as those of the blocks that contain the snapshot inodes.
238  * The list is sorted into block order to allow binary search lookup.
239  *
240  * The twelve direct direct block pointers of the snapshot are always
241  * copied, so we test for them first before checking the list itself
242  * (i.e., they are not in the list).
243  *
244  * The checksnapinfo() routine needs to ensure that the list contains at
245  * least the super block, its summary information, and the cylinder groups.
246  * Here we check the list first for the superblock, zero or more cylinder
247  * groups up to the location of the superblock summary information, the
248  * summary group information, and any remaining cylinder group maps that
249  * follow it. We skip over any other entries in the list.
250  */
251 #define CHKBLKINLIST(chkblk)						\
252 	/* All UFS_NDADDR blocks are copied */				\
253 	if ((chkblk) >= UFS_NDADDR) {					\
254 		/* Skip over blocks that are not of interest */		\
255 		while (*blkp < (chkblk) && blkp < lastblkp)		\
256 			blkp++;						\
257 		/* Fail if end of list and not all blocks found */	\
258 		if (blkp >= lastblkp) {					\
259 			pwarn("UFS%d snapshot inode %jd failed: "	\
260 			    "improper block list length (%jd)\n",	\
261 			    sblock.fs_magic == FS_UFS1_MAGIC ? 1 : 2,	\
262 			    (intmax_t)snapip->i_number,			\
263 			    (intmax_t)(lastblkp - &snapblklist[0]));	\
264 			status = 0;					\
265 		}							\
266 		/* Fail if block we seek is missing */			\
267 		else if (*blkp++ != (chkblk)) {				\
268 			pwarn("UFS%d snapshot inode %jd failed: "	\
269 			    "block list (%jd) != %s (%jd)\n",		\
270 			    sblock.fs_magic == FS_UFS1_MAGIC ? 1 : 2,	\
271 			    (intmax_t)snapip->i_number,			\
272 			    (intmax_t)blkp[-1],	#chkblk,		\
273 			    (intmax_t)chkblk);				\
274 			status = 0;					\
275 		}							\
276 	}
277 
278 static int
279 checksnapinfo(struct inode *snapip)
280 {
281 	struct fs *fs;
282 	struct bufarea *bp;
283 	struct inodesc idesc;
284 	daddr_t *snapblklist, *blkp, *lastblkp, csblkno;
285 	int cg, loc, len, status;
286 	ufs_lbn_t lbn;
287 	size_t size;
288 
289 	fs = &sblock;
290 	memset(&idesc, 0, sizeof(struct inodesc));
291 	idesc.id_type = ADDR;
292 	idesc.id_func = getlbnblkno;
293 	idesc.id_number = snapip->i_number;
294 	lbn = howmany(fs->fs_size, fs->fs_frag);
295 	idesc.id_parent = lbn;		/* sought after blkno */
296 	if ((ckinode(snapip->i_dp, &idesc) & FOUND) == 0)
297 		return (0);
298 	size = fragroundup(fs,
299 	    DIP(snapip->i_dp, di_size) - lblktosize(fs, lbn));
300 	bp = getdatablk(idesc.id_parent, size, BT_DATA);
301 	if (bp->b_errs != 0)
302 		return (0);
303 	snapblklist = (daddr_t *)bp->b_un.b_buf;
304 	/*
305 	 * snapblklist[0] is the size of the list
306 	 * snapblklist[1] is the first element of the list
307 	 *
308 	 * We need to be careful to bound the size of the list and verify
309 	 * that we have not run off the end of it if it or its size has
310 	 * been corrupted.
311 	 */
312 	blkp = &snapblklist[1];
313 	lastblkp = &snapblklist[MAX(0,
314 	    MIN(snapblklist[0] + 1, size / sizeof(daddr_t)))];
315 	status = 1;
316 	/* Check that the superblock is listed. */
317 	CHKBLKINLIST(lblkno(fs, fs->fs_sblockloc));
318 	if (status == 0)
319 		goto out;
320 	/*
321 	 * Calculate where the summary information is located.
322 	 * Usually it is in the first cylinder group, but growfs
323 	 * may move it to the first cylinder group that it adds.
324 	 *
325 	 * Check all cylinder groups up to the summary information.
326 	 */
327 	csblkno = fragstoblks(fs, fs->fs_csaddr);
328 	for (cg = 0; cg < fs->fs_ncg; cg++) {
329 		if (fragstoblks(fs, cgtod(fs, cg)) > csblkno)
330 			break;
331 		CHKBLKINLIST(fragstoblks(fs, cgtod(fs, cg)));
332 		if (status == 0)
333 			goto out;
334 	}
335 	/* Check the summary information block(s). */
336 	len = howmany(fs->fs_cssize, fs->fs_bsize);
337 	for (loc = 0; loc < len; loc++) {
338 		CHKBLKINLIST(csblkno + loc);
339 		if (status == 0)
340 			goto out;
341 	}
342 	/* Check the remaining cylinder groups. */
343 	for (; cg < fs->fs_ncg; cg++) {
344 		CHKBLKINLIST(fragstoblks(fs, cgtod(fs, cg)));
345 		if (status == 0)
346 			goto out;
347 	}
348 out:
349 	brelse(bp);
350 	return (status);
351 }
352 
353 /*
354  * Return the block number associated with a specified inode lbn.
355  * Requested lbn is in id_parent. If found, block is returned in
356  * id_parent.
357  */
358 static int
359 getlbnblkno(struct inodesc *idesc)
360 {
361 
362 	if (idesc->id_lbn < idesc->id_parent)
363 		return (KEEPON);
364 	idesc->id_parent = idesc->id_blkno;
365 	return (STOP | FOUND);
366 }
367 
368 /*
369  * Open a device or file to be checked by fsck.
370  */
371 int
372 openfilesys(char *dev)
373 {
374 	struct stat statb;
375 	int saved_fsreadfd;
376 
377 	if (stat(dev, &statb) < 0)
378 		return (0);
379 	if ((statb.st_mode & S_IFMT) != S_IFCHR &&
380 	    (statb.st_mode & S_IFMT) != S_IFBLK) {
381 		if (bkgrdflag != 0 && (statb.st_flags & SF_SNAPSHOT) == 0) {
382 			pwarn("BACKGROUND FSCK LACKS A SNAPSHOT\n");
383 			return (0);
384 		}
385 		if (bkgrdflag != 0) {
386 			cursnapshot = statb.st_ino;
387 		} else {
388 			pwarn("%s IS NOT A DISK DEVICE\n", dev);
389 			if (preen || reply("CONTINUE") == 0)
390 				return (0);
391 		}
392 	}
393 	saved_fsreadfd = fsreadfd;
394 	if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
395 		fsreadfd = saved_fsreadfd;
396 		return (0);
397 	}
398 	if (saved_fsreadfd != -1)
399 		close(saved_fsreadfd);
400 	return (1);
401 }
402 
403 /*
404  * Read in the super block and its summary info.
405  */
406 int
407 readsb(void)
408 {
409 	struct fs *fs;
410 
411 	sbhashfailed = 0;
412 	readcnt[sblk.b_type]++;
413 	/*
414 	 * If bflag is given, then check just that superblock.
415 	 */
416 	if (bflag) {
417 		switch (sbget(fsreadfd, &fs, bflag * dev_bsize, 0)) {
418 		case 0:
419 			goto goodsb;
420 		case EINTEGRITY:
421 			printf("Check hash failed for superblock at %jd\n",
422 			    bflag);
423 			return (0);
424 		case ENOENT:
425 			printf("%jd is not a file system superblock\n", bflag);
426 			return (0);
427 		case EIO:
428 		default:
429 			printf("I/O error reading %jd\n", bflag);
430 			return (0);
431 		}
432 	}
433 	/*
434 	 * Check for the standard superblock and use it if good.
435 	 */
436 	if (sbget(fsreadfd, &fs, UFS_STDSB, UFS_NOMSG) == 0)
437 		goto goodsb;
438 	/*
439 	 * Check if the only problem is a check-hash failure.
440 	 */
441 	skipclean = 0;
442 	if (sbget(fsreadfd, &fs, UFS_STDSB, UFS_NOMSG | UFS_NOHASHFAIL) == 0) {
443 		sbhashfailed = 1;
444 		goto goodsb;
445 	}
446 	/*
447 	 * Do an exhaustive search for a usable superblock.
448 	 */
449 	switch (sbsearch(fsreadfd, &fs, 0)) {
450 	case 0:
451 		goto goodsb;
452 	case ENOENT:
453 		printf("SEARCH FOR ALTERNATE SUPER-BLOCK FAILED. "
454 		    "YOU MUST USE THE\n-b OPTION TO FSCK TO SPECIFY "
455 		    "THE LOCATION OF AN ALTERNATE\nSUPER-BLOCK TO "
456 		    "SUPPLY NEEDED INFORMATION; SEE fsck_ffs(8).\n");
457 		return (0);
458 	case EIO:
459 	default:
460 		printf("I/O error reading a usable superblock\n");
461 		return (0);
462 	}
463 
464 goodsb:
465 	memcpy(&sblock, fs, fs->fs_sbsize);
466 	free(fs);
467 	/*
468 	 * Compute block size that the file system is based on,
469 	 * according to fsbtodb, and adjust superblock block number
470 	 * so we can tell if this is an alternate later.
471 	 */
472 	dev_bsize = sblock.fs_fsize / fsbtodb(&sblock, 1);
473 	sblk.b_bno = sblock.fs_sblockactualloc / dev_bsize;
474 	sblk.b_size = SBLOCKSIZE;
475 	/*
476 	 * If not yet done, update UFS1 superblock with new wider fields.
477 	 */
478 	if (sblock.fs_magic == FS_UFS1_MAGIC &&
479 	    sblock.fs_maxbsize != sblock.fs_bsize) {
480 		sblock.fs_maxbsize = sblock.fs_bsize;
481 		sblock.fs_time = sblock.fs_old_time;
482 		sblock.fs_size = sblock.fs_old_size;
483 		sblock.fs_dsize = sblock.fs_old_dsize;
484 		sblock.fs_csaddr = sblock.fs_old_csaddr;
485 		sblock.fs_cstotal.cs_ndir = sblock.fs_old_cstotal.cs_ndir;
486 		sblock.fs_cstotal.cs_nbfree = sblock.fs_old_cstotal.cs_nbfree;
487 		sblock.fs_cstotal.cs_nifree = sblock.fs_old_cstotal.cs_nifree;
488 		sblock.fs_cstotal.cs_nffree = sblock.fs_old_cstotal.cs_nffree;
489 	}
490 	havesb = 1;
491 	return (1);
492 }
493 
494 void
495 sblock_init(void)
496 {
497 
498 	fsreadfd = -1;
499 	fswritefd = -1;
500 	fsmodified = 0;
501 	lfdir = 0;
502 	initbarea(&sblk, BT_SUPERBLK);
503 	sblk.b_un.b_buf = Balloc(SBLOCKSIZE);
504 	if (sblk.b_un.b_buf == NULL)
505 		errx(EEXIT, "cannot allocate space for superblock");
506 	dev_bsize = secsize = DEV_BSIZE;
507 }
508 
509 /*
510  * Calculate a prototype superblock based on information in the boot area.
511  * When done the cgsblock macro can be calculated and the fs_ncg field
512  * can be used. Do NOT attempt to use other macros without verifying that
513  * their needed information is available!
514  */
515 static int
516 calcsb(char *dev, int devfd, struct fs *fs)
517 {
518 	struct fsrecovery *fsr;
519 	char *fsrbuf;
520 	u_int secsize;
521 
522 	/*
523 	 * We need fragments-per-group and the partition-size.
524 	 *
525 	 * Newfs stores these details at the end of the boot block area
526 	 * at the start of the filesystem partition. If they have been
527 	 * overwritten by a boot block, we fail. But usually they are
528 	 * there and we can use them.
529 	 */
530 	if (ioctl(devfd, DIOCGSECTORSIZE, &secsize) == -1)
531 		return (0);
532 	fsrbuf = Balloc(secsize);
533 	if (fsrbuf == NULL)
534 		errx(EEXIT, "calcsb: cannot allocate recovery buffer");
535 	if (blread(devfd, fsrbuf,
536 	    (SBLOCK_UFS2 - secsize) / dev_bsize, secsize) != 0) {
537 		free(fsrbuf);
538 		return (0);
539 	}
540 	fsr = (struct fsrecovery *)&fsrbuf[secsize - sizeof *fsr];
541 	if (fsr->fsr_magic != FS_UFS2_MAGIC) {
542 		free(fsrbuf);
543 		return (0);
544 	}
545 	memset(fs, 0, sizeof(struct fs));
546 	fs->fs_fpg = fsr->fsr_fpg;
547 	fs->fs_fsbtodb = fsr->fsr_fsbtodb;
548 	fs->fs_sblkno = fsr->fsr_sblkno;
549 	fs->fs_magic = fsr->fsr_magic;
550 	fs->fs_ncg = fsr->fsr_ncg;
551 	free(fsrbuf);
552 	return (1);
553 }
554 
555 /*
556  * Check to see if recovery information exists.
557  * Return 1 if it exists or cannot be created.
558  * Return 0 if it does not exist and can be created.
559  */
560 static int
561 chkrecovery(int devfd)
562 {
563 	struct fsrecovery *fsr;
564 	char *fsrbuf;
565 	u_int secsize, rdsize;
566 
567 	/*
568 	 * Could not determine if backup material exists, so do not
569 	 * offer to create it.
570 	 */
571 	fsrbuf = NULL;
572 	rdsize = sblock.fs_fsize;
573 	if (ioctl(devfd, DIOCGSECTORSIZE, &secsize) == -1 ||
574 	    rdsize % secsize != 0 ||
575 	    (fsrbuf = Balloc(rdsize)) == NULL ||
576 	    blread(devfd, fsrbuf, (SBLOCK_UFS2 - rdsize) / dev_bsize,
577 	      rdsize) != 0) {
578 		free(fsrbuf);
579 		return (1);
580 	}
581 	/*
582 	 * Recovery material has already been created, so do not
583 	 * need to create it again.
584 	 */
585 	fsr = (struct fsrecovery *)&fsrbuf[rdsize - sizeof *fsr];
586 	if (fsr->fsr_magic == FS_UFS2_MAGIC) {
587 		free(fsrbuf);
588 		return (1);
589 	}
590 	/*
591 	 * Recovery material has not been created and can be if desired.
592 	 */
593 	free(fsrbuf);
594 	return (0);
595 }
596 
597 /*
598  * Read the last filesystem-size piece of the boot block, replace the
599  * last 20 bytes with the recovery information, then write it back.
600  * The recovery information only works for UFS2 filesystems.
601  */
602 static void
603 saverecovery(int readfd, int writefd)
604 {
605 	struct fsrecovery *fsr;
606 	char *fsrbuf;
607 	u_int secsize, rdsize;
608 
609 	fsrbuf = NULL;
610 	rdsize = sblock.fs_fsize;
611 	if (sblock.fs_magic != FS_UFS2_MAGIC ||
612 	    ioctl(readfd, DIOCGSECTORSIZE, &secsize) == -1 ||
613 	    rdsize % secsize != 0 ||
614 	    (fsrbuf = Balloc(rdsize)) == NULL ||
615 	    blread(readfd, fsrbuf, (SBLOCK_UFS2 - rdsize) / dev_bsize,
616 	      rdsize) != 0) {
617 		printf("RECOVERY DATA COULD NOT BE CREATED\n");
618 		free(fsrbuf);
619 		return;
620 	}
621 	fsr = (struct fsrecovery *)&fsrbuf[rdsize - sizeof *fsr];
622 	fsr->fsr_magic = sblock.fs_magic;
623 	fsr->fsr_fpg = sblock.fs_fpg;
624 	fsr->fsr_fsbtodb = sblock.fs_fsbtodb;
625 	fsr->fsr_sblkno = sblock.fs_sblkno;
626 	fsr->fsr_ncg = sblock.fs_ncg;
627 	blwrite(writefd, fsrbuf, (SBLOCK_UFS2 - rdsize) / dev_bsize, rdsize);
628 	free(fsrbuf);
629 }
630