xref: /freebsd/sys/ufs/ffs/ffs_subr.c (revision e1ebda4458bbaf7d85fb803e20f3afc5441f24d9)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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 
32 #include <sys/param.h>
33 #include <sys/endian.h>
34 #include <sys/limits.h>
35 
36 #ifndef _KERNEL
37 #include <stdbool.h>
38 #include <stdio.h>
39 #include <string.h>
40 #include <stdlib.h>
41 #include <time.h>
42 #include <sys/errno.h>
43 #include <ufs/ufs/dinode.h>
44 #include <ufs/ffs/fs.h>
45 
46 uint32_t calculate_crc32c(uint32_t, const void *, size_t);
47 uint32_t ffs_calc_sbhash(struct fs *);
48 struct malloc_type;
49 #define UFS_MALLOC(size, type, flags) malloc(size)
50 #define UFS_FREE(ptr, type) free(ptr)
51 #define maxphys MAXPHYS
52 
53 #else /* _KERNEL */
54 #include <sys/systm.h>
55 #include <sys/gsb_crc32.h>
56 #include <sys/lock.h>
57 #include <sys/malloc.h>
58 #include <sys/mount.h>
59 #include <sys/vnode.h>
60 #include <sys/bio.h>
61 #include <sys/buf.h>
62 #include <sys/ucred.h>
63 #include <sys/sysctl.h>
64 
65 #include <ufs/ufs/quota.h>
66 #include <ufs/ufs/inode.h>
67 #include <ufs/ufs/extattr.h>
68 #include <ufs/ufs/ufsmount.h>
69 #include <ufs/ufs/ufs_extern.h>
70 #include <ufs/ffs/ffs_extern.h>
71 #include <ufs/ffs/fs.h>
72 
73 #define UFS_MALLOC(size, type, flags) malloc(size, type, flags)
74 #define UFS_FREE(ptr, type) free(ptr, type)
75 
76 #endif /* _KERNEL */
77 
78 /*
79  * Verify an inode check-hash.
80  */
81 int
82 ffs_verify_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip)
83 {
84 	uint32_t ckhash, save_ckhash;
85 
86 	/*
87 	 * Return success if unallocated or we are not doing inode check-hash.
88 	 */
89 	if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0)
90 		return (0);
91 	/*
92 	 * Exclude di_ckhash from the crc32 calculation, e.g., always use
93 	 * a check-hash value of zero when calculating the check-hash.
94 	 */
95 	save_ckhash = dip->di_ckhash;
96 	dip->di_ckhash = 0;
97 	ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip));
98 	dip->di_ckhash = save_ckhash;
99 	if (save_ckhash == ckhash)
100 		return (0);
101 	return (EINVAL);
102 }
103 
104 /*
105  * Update an inode check-hash.
106  */
107 void
108 ffs_update_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip)
109 {
110 
111 	if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0)
112 		return;
113 	/*
114 	 * Exclude old di_ckhash from the crc32 calculation, e.g., always use
115 	 * a check-hash value of zero when calculating the new check-hash.
116 	 */
117 	dip->di_ckhash = 0;
118 	dip->di_ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip));
119 }
120 
121 /*
122  * These are the low-level functions that actually read and write
123  * the superblock and its associated data.
124  */
125 static off_t sblock_try[] = SBLOCKSEARCH;
126 static int readsuper(void *, struct fs **, off_t, int,
127 	int (*)(void *, off_t, void **, int));
128 static void ffs_oldfscompat_read(struct fs *, ufs2_daddr_t);
129 static int validate_sblock(struct fs *, int);
130 
131 /*
132  * Read a superblock from the devfd device.
133  *
134  * If an alternate superblock is specified, it is read. Otherwise the
135  * set of locations given in the SBLOCKSEARCH list is searched for a
136  * superblock. Memory is allocated for the superblock by the readfunc and
137  * is returned. If filltype is non-NULL, additional memory is allocated
138  * of type filltype and filled in with the superblock summary information.
139  * All memory is freed when any error is returned.
140  *
141  * If a superblock is found, zero is returned. Otherwise one of the
142  * following error values is returned:
143  *     EIO: non-existent or truncated superblock.
144  *     EIO: error reading summary information.
145  *     ENOENT: no usable known superblock found.
146  *     EILSEQ: filesystem with wrong byte order found.
147  *     ENOMEM: failed to allocate space for the superblock.
148  *     EINVAL: The previous newfs operation on this volume did not complete.
149  *         The administrator must complete newfs before using this volume.
150  */
151 int
152 ffs_sbget(void *devfd, struct fs **fsp, off_t sblock, int flags,
153     struct malloc_type *filltype,
154     int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
155 {
156 	struct fs *fs;
157 	struct fs_summary_info *fs_si;
158 	int i, error;
159 	uint64_t size, blks;
160 	uint8_t *space;
161 	int32_t *lp;
162 	char *buf;
163 
164 	fs = NULL;
165 	*fsp = NULL;
166 	if (sblock != UFS_STDSB) {
167 		if ((error = readsuper(devfd, &fs, sblock,
168 		    flags | UFS_ALTSBLK, readfunc)) != 0) {
169 			if (fs != NULL)
170 				UFS_FREE(fs, filltype);
171 			return (error);
172 		}
173 	} else {
174 		for (i = 0; sblock_try[i] != -1; i++) {
175 			if ((error = readsuper(devfd, &fs, sblock_try[i],
176 			     flags, readfunc)) == 0) {
177 				if ((flags & UFS_NOCSUM) != 0) {
178 					*fsp = fs;
179 					return (0);
180 				}
181 				break;
182 			}
183 			if (fs != NULL) {
184 				UFS_FREE(fs, filltype);
185 				fs = NULL;
186 			}
187 			if (error == ENOENT)
188 				continue;
189 			return (error);
190 		}
191 		if (sblock_try[i] == -1)
192 			return (ENOENT);
193 	}
194 	/*
195 	 * Read in the superblock summary information.
196 	 */
197 	size = fs->fs_cssize;
198 	blks = howmany(size, fs->fs_fsize);
199 	if (fs->fs_contigsumsize > 0)
200 		size += fs->fs_ncg * sizeof(int32_t);
201 	size += fs->fs_ncg * sizeof(uint8_t);
202 	if ((fs_si = UFS_MALLOC(sizeof(*fs_si), filltype, M_NOWAIT)) == NULL) {
203 		UFS_FREE(fs, filltype);
204 		return (ENOMEM);
205 	}
206 	bzero(fs_si, sizeof(*fs_si));
207 	fs->fs_si = fs_si;
208 	if ((space = UFS_MALLOC(size, filltype, M_NOWAIT)) == NULL) {
209 		UFS_FREE(fs->fs_si, filltype);
210 		UFS_FREE(fs, filltype);
211 		return (ENOMEM);
212 	}
213 	fs->fs_csp = (struct csum *)space;
214 	for (i = 0; i < blks; i += fs->fs_frag) {
215 		size = fs->fs_bsize;
216 		if (i + fs->fs_frag > blks)
217 			size = (blks - i) * fs->fs_fsize;
218 		buf = NULL;
219 		error = (*readfunc)(devfd,
220 		    dbtob(fsbtodb(fs, fs->fs_csaddr + i)), (void **)&buf, size);
221 		if (error) {
222 			if (buf != NULL)
223 				UFS_FREE(buf, filltype);
224 			UFS_FREE(fs->fs_csp, filltype);
225 			UFS_FREE(fs->fs_si, filltype);
226 			UFS_FREE(fs, filltype);
227 			return (error);
228 		}
229 		memcpy(space, buf, size);
230 		UFS_FREE(buf, filltype);
231 		space += size;
232 	}
233 	if (fs->fs_contigsumsize > 0) {
234 		fs->fs_maxcluster = lp = (int32_t *)space;
235 		for (i = 0; i < fs->fs_ncg; i++)
236 			*lp++ = fs->fs_contigsumsize;
237 		space = (uint8_t *)lp;
238 	}
239 	size = fs->fs_ncg * sizeof(uint8_t);
240 	fs->fs_contigdirs = (uint8_t *)space;
241 	bzero(fs->fs_contigdirs, size);
242 	*fsp = fs;
243 	return (0);
244 }
245 
246 /*
247  * Try to read a superblock from the location specified by sblockloc.
248  * Return zero on success or an errno on failure.
249  */
250 static int
251 readsuper(void *devfd, struct fs **fsp, off_t sblockloc, int flags,
252     int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
253 {
254 	struct fs *fs;
255 	int error, res;
256 	uint32_t ckhash;
257 
258 	error = (*readfunc)(devfd, sblockloc, (void **)fsp, SBLOCKSIZE);
259 	if (error != 0)
260 		return (error);
261 	fs = *fsp;
262 	if (fs->fs_magic == FS_BAD_MAGIC)
263 		return (EINVAL);
264 	/*
265 	 * For UFS1 with a 65536 block size, the first backup superblock
266 	 * is at the same location as the UFS2 superblock. Since SBLOCK_UFS2
267 	 * is the first location checked, the first backup is the superblock
268 	 * that will be accessed. Here we fail the lookup so that we can
269 	 * retry with the correct location for the UFS1 superblock.
270 	 */
271 	if (fs->fs_magic == FS_UFS1_MAGIC && (flags & UFS_ALTSBLK) == 0 &&
272 	    fs->fs_bsize == SBLOCK_UFS2 && sblockloc == SBLOCK_UFS2)
273 		return (ENOENT);
274 	ffs_oldfscompat_read(fs, sblockloc);
275 	if ((error = validate_sblock(fs, flags)) > 0)
276 		return (error);
277 	/*
278 	 * If the filesystem has been run on a kernel without
279 	 * metadata check hashes, disable them.
280 	 */
281 	if ((fs->fs_flags & FS_METACKHASH) == 0)
282 		fs->fs_metackhash = 0;
283 	/*
284 	 * Clear any check-hashes that are not maintained
285 	 * by this kernel. Also clear any unsupported flags.
286 	 */
287 	fs->fs_metackhash &= CK_SUPPORTED;
288 	fs->fs_flags &= FS_SUPPORTED;
289 	if (fs->fs_ckhash != (ckhash = ffs_calc_sbhash(fs))) {
290 		if ((flags & (UFS_NOMSG | UFS_NOHASHFAIL)) ==
291 		    (UFS_NOMSG | UFS_NOHASHFAIL))
292 			return (0);
293 		if ((flags & UFS_NOMSG) != 0)
294 			return (EINTEGRITY);
295 #ifdef _KERNEL
296 		res = uprintf("Superblock check-hash failed: recorded "
297 		    "check-hash 0x%x != computed check-hash 0x%x%s\n",
298 		    fs->fs_ckhash, ckhash,
299 		    (flags & UFS_NOHASHFAIL) != 0 ? " (Ignored)" : "");
300 #else
301 		res = 0;
302 #endif
303 		/*
304 		 * Print check-hash failure if no controlling terminal
305 		 * in kernel or always if in user-mode (libufs).
306 		 */
307 		if (res == 0)
308 			printf("Superblock check-hash failed: recorded "
309 			    "check-hash 0x%x != computed check-hash "
310 			    "0x%x%s\n", fs->fs_ckhash, ckhash,
311 			    (flags & UFS_NOHASHFAIL) ? " (Ignored)" : "");
312 		if ((flags & UFS_NOHASHFAIL) != 0)
313 			return (0);
314 		return (EINTEGRITY);
315 	}
316 	/* Have to set for old filesystems that predate this field */
317 	fs->fs_sblockactualloc = sblockloc;
318 	/* Not yet any summary information */
319 	fs->fs_si = NULL;
320 	return (0);
321 }
322 
323 /*
324  * Sanity checks for loading old filesystem superblocks.
325  * See ffs_oldfscompat_write below for unwound actions.
326  *
327  * XXX - Parts get retired eventually.
328  * Unfortunately new bits get added.
329  */
330 static void
331 ffs_oldfscompat_read(struct fs *fs, ufs2_daddr_t sblockloc)
332 {
333 	uint64_t maxfilesize;
334 
335 	/*
336 	 * If not yet done, update fs_flags location and value of fs_sblockloc.
337 	 */
338 	if ((fs->fs_old_flags & FS_FLAGS_UPDATED) == 0) {
339 		fs->fs_flags = fs->fs_old_flags;
340 		fs->fs_old_flags |= FS_FLAGS_UPDATED;
341 		fs->fs_sblockloc = sblockloc;
342 	}
343 	/*
344 	 * If not yet done, update UFS1 superblock with new wider fields.
345 	 */
346 	if (fs->fs_magic == FS_UFS1_MAGIC && fs->fs_maxbsize != fs->fs_bsize) {
347 		fs->fs_maxbsize = fs->fs_bsize;
348 		fs->fs_time = fs->fs_old_time;
349 		fs->fs_size = fs->fs_old_size;
350 		fs->fs_dsize = fs->fs_old_dsize;
351 		fs->fs_csaddr = fs->fs_old_csaddr;
352 		fs->fs_cstotal.cs_ndir = fs->fs_old_cstotal.cs_ndir;
353 		fs->fs_cstotal.cs_nbfree = fs->fs_old_cstotal.cs_nbfree;
354 		fs->fs_cstotal.cs_nifree = fs->fs_old_cstotal.cs_nifree;
355 		fs->fs_cstotal.cs_nffree = fs->fs_old_cstotal.cs_nffree;
356 	}
357 	if (fs->fs_magic == FS_UFS1_MAGIC &&
358 	    fs->fs_old_inodefmt < FS_44INODEFMT) {
359 		fs->fs_maxfilesize = ((uint64_t)1 << 31) - 1;
360 		fs->fs_qbmask = ~fs->fs_bmask;
361 		fs->fs_qfmask = ~fs->fs_fmask;
362 	}
363 	if (fs->fs_magic == FS_UFS1_MAGIC) {
364 		fs->fs_save_maxfilesize = fs->fs_maxfilesize;
365 		maxfilesize = (uint64_t)0x80000000 * fs->fs_bsize - 1;
366 		if (fs->fs_maxfilesize > maxfilesize)
367 			fs->fs_maxfilesize = maxfilesize;
368 	}
369 	/* Compatibility for old filesystems */
370 	if (fs->fs_avgfilesize <= 0)
371 		fs->fs_avgfilesize = AVFILESIZ;
372 	if (fs->fs_avgfpdir <= 0)
373 		fs->fs_avgfpdir = AFPDIR;
374 }
375 
376 /*
377  * Unwinding superblock updates for old filesystems.
378  * See ffs_oldfscompat_read above for details.
379  *
380  * XXX - Parts get retired eventually.
381  * Unfortunately new bits get added.
382  */
383 void
384 ffs_oldfscompat_write(struct fs *fs)
385 {
386 
387 	/*
388 	 * Copy back UFS2 updated fields that UFS1 inspects.
389 	 */
390 	if (fs->fs_magic == FS_UFS1_MAGIC) {
391 		fs->fs_old_time = fs->fs_time;
392 		fs->fs_old_cstotal.cs_ndir = fs->fs_cstotal.cs_ndir;
393 		fs->fs_old_cstotal.cs_nbfree = fs->fs_cstotal.cs_nbfree;
394 		fs->fs_old_cstotal.cs_nifree = fs->fs_cstotal.cs_nifree;
395 		fs->fs_old_cstotal.cs_nffree = fs->fs_cstotal.cs_nffree;
396 		fs->fs_maxfilesize = fs->fs_save_maxfilesize;
397 	}
398 }
399 
400 /*
401  * Sanity checks for loading old filesystem inodes.
402  *
403  * XXX - Parts get retired eventually.
404  * Unfortunately new bits get added.
405  */
406 static int prttimechgs = 0;
407 #ifdef _KERNEL
408 SYSCTL_NODE(_vfs, OID_AUTO, ffs, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
409     "FFS filesystem");
410 
411 SYSCTL_INT(_vfs_ffs, OID_AUTO, prttimechgs, CTLFLAG_RWTUN, &prttimechgs, 0,
412 	"print UFS1 time changes made to inodes");
413 #endif /* _KERNEL */
414 bool
415 ffs_oldfscompat_inode_read(struct fs *fs, union dinodep dp, time_t now)
416 {
417 	bool change;
418 
419 	change = false;
420 	switch (fs->fs_magic) {
421 	case FS_UFS2_MAGIC:
422 		/* No changes for now */
423 		break;
424 
425 	case FS_UFS1_MAGIC:
426 		/*
427 		 * With the change to unsigned time values in UFS1, times set
428 		 * before Jan 1, 1970 will appear to be in the future. Check
429 		 * for future times and set them to be the current time.
430 		 */
431 		if (dp.dp1->di_ctime > now) {
432 			if (prttimechgs)
433 				printf("ctime %ud changed to %ld\n",
434 				    dp.dp1->di_ctime, (long)now);
435 			dp.dp1->di_ctime = now;
436 			change = true;
437 		}
438 		if (dp.dp1->di_mtime > now) {
439 			if (prttimechgs)
440 				printf("mtime %ud changed to %ld\n",
441 				    dp.dp1->di_mtime, (long)now);
442 			dp.dp1->di_mtime = now;
443 			dp.dp1->di_ctime = now;
444 			change = true;
445 		}
446 		if (dp.dp1->di_atime > now) {
447 			if (prttimechgs)
448 				printf("atime %ud changed to %ld\n",
449 				    dp.dp1->di_atime, (long)now);
450 			dp.dp1->di_atime = now;
451 			dp.dp1->di_ctime = now;
452 			change = true;
453 		}
454 		break;
455 	}
456 	return (change);
457 }
458 
459 /*
460  * Verify the filesystem values.
461  */
462 #define ILOG2(num)	(fls(num) - 1)
463 #ifdef STANDALONE_SMALL
464 #define MPRINT(...)	do { } while (0)
465 #else
466 #define MPRINT(...)	if (prtmsg) printf(__VA_ARGS__)
467 #endif
468 #define FCHK(lhs, op, rhs, fmt)						\
469 	if (lhs op rhs) {						\
470 		MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s ("	\
471 		    #fmt ")\n", fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2,	\
472 		    #lhs, (intmax_t)lhs, #op, #rhs, (intmax_t)rhs);	\
473 		if (error < 0)						\
474 			return (ENOENT);				\
475 		if (error == 0)						\
476 			error = ENOENT;					\
477 	}
478 #define WCHK(lhs, op, rhs, fmt)						\
479 	if (lhs op rhs) {						\
480 		MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s ("	\
481 		    #fmt ")%s\n", fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2,\
482 		    #lhs, (intmax_t)lhs, #op, #rhs, (intmax_t)rhs, wmsg);\
483 		if (error == 0)						\
484 			error = warnerr;				\
485 		if (warnerr == 0)					\
486 			lhs = rhs;					\
487 	}
488 #define FCHK2(lhs1, op1, rhs1, lhs2, op2, rhs2, fmt)			\
489 	if (lhs1 op1 rhs1 && lhs2 op2 rhs2) {				\
490 		MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s ("	\
491 		    #fmt ") && %s (" #fmt ") %s %s (" #fmt ")\n",	\
492 		    fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2, #lhs1,	\
493 		    (intmax_t)lhs1, #op1, #rhs1, (intmax_t)rhs1, #lhs2,	\
494 		    (intmax_t)lhs2, #op2, #rhs2, (intmax_t)rhs2);	\
495 		if (error < 0)						\
496 			return (ENOENT);				\
497 		if (error == 0)						\
498 			error = ENOENT;					\
499 	}
500 
501 static int
502 validate_sblock(struct fs *fs, int flags)
503 {
504 	uint64_t i, sectorsize;
505 	uint64_t maxfilesize, sizepb;
506 	int error, prtmsg, warnerr;
507 	char *wmsg;
508 
509 	error = 0;
510 	sectorsize = dbtob(1);
511 	prtmsg = ((flags & UFS_NOMSG) == 0);
512 	warnerr = (flags & UFS_NOWARNFAIL) == UFS_NOWARNFAIL ? 0 : ENOENT;
513 	wmsg = warnerr ? "" : " (Ignored)";
514 	/*
515 	 * Check for endian mismatch between machine and filesystem.
516 	 */
517 	if (((fs->fs_magic != FS_UFS2_MAGIC) &&
518 	    (bswap32(fs->fs_magic) == FS_UFS2_MAGIC)) ||
519 	    ((fs->fs_magic != FS_UFS1_MAGIC) &&
520 	    (bswap32(fs->fs_magic) == FS_UFS1_MAGIC))) {
521 		MPRINT("UFS superblock failed due to endian mismatch "
522 		    "between machine and filesystem\n");
523 		return(EILSEQ);
524 	}
525 	/*
526 	 * If just validating for recovery, then do just the minimal
527 	 * checks needed for the superblock fields needed to find
528 	 * alternate superblocks.
529 	 */
530 	if ((flags & UFS_FSRONLY) == UFS_FSRONLY &&
531 	    (fs->fs_magic == FS_UFS1_MAGIC || fs->fs_magic == FS_UFS2_MAGIC)) {
532 		error = -1; /* fail on first error */
533 		if (fs->fs_magic == FS_UFS2_MAGIC) {
534 			FCHK(fs->fs_sblockloc, !=, SBLOCK_UFS2, %#jx);
535 		} else if (fs->fs_magic == FS_UFS1_MAGIC) {
536 			FCHK(fs->fs_sblockloc, <, 0, %jd);
537 			FCHK(fs->fs_sblockloc, >, SBLOCK_UFS1, %jd);
538 		}
539 		FCHK(fs->fs_frag, <, 1, %jd);
540 		FCHK(fs->fs_frag, >, MAXFRAG, %jd);
541 		FCHK(fs->fs_bsize, <, MINBSIZE, %jd);
542 		FCHK(fs->fs_bsize, >, MAXBSIZE, %jd);
543 		FCHK(fs->fs_bsize, <, roundup(sizeof(struct fs), DEV_BSIZE),
544 		    %jd);
545 		FCHK(fs->fs_fsize, <, sectorsize, %jd);
546 		FCHK(fs->fs_fsize * fs->fs_frag, !=, fs->fs_bsize, %jd);
547 		FCHK(powerof2(fs->fs_fsize), ==, 0, %jd);
548 		FCHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
549 		FCHK(fs->fs_sbsize, <, (signed)sizeof(struct fs), %jd);
550 		FCHK(fs->fs_sbsize % sectorsize, !=, 0, %jd);
551 		FCHK(fs->fs_fpg, <, 3 * fs->fs_frag, %jd);
552 		FCHK(fs->fs_ncg, <, 1, %jd);
553 		FCHK(fs->fs_fsbtodb, !=, ILOG2(fs->fs_fsize / sectorsize), %jd);
554 		FCHK(fs->fs_old_cgoffset, <, 0, %jd);
555 		FCHK2(fs->fs_old_cgoffset, >, 0, ~fs->fs_old_cgmask, <, 0, %jd);
556 		FCHK(fs->fs_old_cgoffset * (~fs->fs_old_cgmask), >, fs->fs_fpg,
557 		    %jd);
558 		FCHK(fs->fs_sblkno, !=, roundup(
559 		    howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize),
560 		    fs->fs_frag), %jd);
561 		FCHK(CGSIZE(fs), >, fs->fs_bsize, %jd);
562 		/* Only need to validate these if reading in csum data */
563 		if ((flags & UFS_NOCSUM) != 0)
564 			return (error);
565 		FCHK((uint64_t)fs->fs_ipg * fs->fs_ncg, >,
566 		    (((int64_t)(1)) << 32) - INOPB(fs), %jd);
567 		FCHK(fs->fs_cstotal.cs_nifree, <, 0, %jd);
568 		FCHK(fs->fs_cstotal.cs_nifree, >,
569 		    (uint64_t)fs->fs_ipg * fs->fs_ncg, %jd);
570 		FCHK(fs->fs_cstotal.cs_ndir, >,
571 		    ((uint64_t)fs->fs_ipg * fs->fs_ncg) -
572 		    fs->fs_cstotal.cs_nifree, %jd);
573 		FCHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
574 		FCHK(fs->fs_size, <=, ((int64_t)fs->fs_ncg - 1) * fs->fs_fpg,
575 		    %jd);
576 		FCHK(fs->fs_size, >, (int64_t)fs->fs_ncg * fs->fs_fpg, %jd);
577 		FCHK(fs->fs_csaddr, <, 0, %jd);
578 		FCHK(fs->fs_cssize, !=,
579 		    fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
580 		FCHK(fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize), >,
581 		    fs->fs_size, %jd);
582 		FCHK(fs->fs_csaddr, <, cgdmin(fs, dtog(fs, fs->fs_csaddr)),
583 		    %jd);
584 		FCHK(dtog(fs, fs->fs_csaddr + howmany(fs->fs_cssize,
585 		    fs->fs_fsize)), >, dtog(fs, fs->fs_csaddr), %jd);
586 		return (error);
587 	}
588 	if (fs->fs_magic == FS_UFS2_MAGIC) {
589 		if ((flags & UFS_ALTSBLK) == 0)
590 			FCHK2(fs->fs_sblockactualloc, !=, SBLOCK_UFS2,
591 			    fs->fs_sblockactualloc, !=, 0, %jd);
592 		FCHK(fs->fs_sblockloc, !=, SBLOCK_UFS2, %#jx);
593 		FCHK(fs->fs_maxsymlinklen, !=, ((UFS_NDADDR + UFS_NIADDR) *
594 			sizeof(ufs2_daddr_t)), %jd);
595 		FCHK(fs->fs_nindir, !=, fs->fs_bsize / sizeof(ufs2_daddr_t),
596 		    %jd);
597 		FCHK(fs->fs_inopb, !=,
598 		    fs->fs_bsize / sizeof(struct ufs2_dinode), %jd);
599 	} else if (fs->fs_magic == FS_UFS1_MAGIC) {
600 		if ((flags & UFS_ALTSBLK) == 0)
601 			FCHK(fs->fs_sblockactualloc, >, SBLOCK_UFS1, %jd);
602 		FCHK(fs->fs_sblockloc, <, 0, %jd);
603 		FCHK(fs->fs_sblockloc, >, SBLOCK_UFS1, %jd);
604 		FCHK(fs->fs_nindir, !=, fs->fs_bsize / sizeof(ufs1_daddr_t),
605 		    %jd);
606 		FCHK(fs->fs_inopb, !=,
607 		    fs->fs_bsize / sizeof(struct ufs1_dinode), %jd);
608 		FCHK(fs->fs_maxsymlinklen, !=, ((UFS_NDADDR + UFS_NIADDR) *
609 			sizeof(ufs1_daddr_t)), %jd);
610 		WCHK(fs->fs_old_inodefmt, !=, FS_44INODEFMT, %jd);
611 		WCHK(fs->fs_old_rotdelay, !=, 0, %jd);
612 		WCHK(fs->fs_old_rps, !=, 60, %jd);
613 		WCHK(fs->fs_old_nspf, !=, fs->fs_fsize / sectorsize, %jd);
614 		WCHK(fs->fs_old_interleave, !=, 1, %jd);
615 		WCHK(fs->fs_old_trackskew, !=, 0, %jd);
616 		WCHK(fs->fs_old_cpc, !=, 0, %jd);
617 		WCHK(fs->fs_old_postblformat, !=, 1, %jd);
618 		FCHK(fs->fs_old_nrpos, !=, 1, %jd);
619 		WCHK(fs->fs_old_nsect, !=, fs->fs_old_spc, %jd);
620 		WCHK(fs->fs_old_npsect, !=, fs->fs_old_spc, %jd);
621 	} else {
622 		/* Bad magic number, so assume not a superblock */
623 		return (ENOENT);
624 	}
625 	FCHK(fs->fs_bsize, <, MINBSIZE, %jd);
626 	FCHK(fs->fs_bsize, >, MAXBSIZE, %jd);
627 	FCHK(fs->fs_bsize, <, roundup(sizeof(struct fs), DEV_BSIZE), %jd);
628 	FCHK(powerof2(fs->fs_bsize), ==, 0, %jd);
629 	FCHK(fs->fs_frag, <, 1, %jd);
630 	FCHK(fs->fs_frag, >, MAXFRAG, %jd);
631 	FCHK(fs->fs_frag, !=, numfrags(fs, fs->fs_bsize), %jd);
632 	FCHK(fs->fs_fsize, <, sectorsize, %jd);
633 	FCHK(fs->fs_fsize * fs->fs_frag, !=, fs->fs_bsize, %jd);
634 	FCHK(powerof2(fs->fs_fsize), ==, 0, %jd);
635 	FCHK(fs->fs_fpg, <, 3 * fs->fs_frag, %jd);
636 	FCHK(fs->fs_ncg, <, 1, %jd);
637 	FCHK(fs->fs_ipg, <, fs->fs_inopb, %jd);
638 	FCHK((uint64_t)fs->fs_ipg * fs->fs_ncg, >,
639 	    (((int64_t)(1)) << 32) - INOPB(fs), %jd);
640 	FCHK(fs->fs_cstotal.cs_nifree, <, 0, %jd);
641 	FCHK(fs->fs_cstotal.cs_nifree, >, (uint64_t)fs->fs_ipg * fs->fs_ncg,
642 	    %jd);
643 	FCHK(fs->fs_cstotal.cs_ndir, <, 0, %jd);
644 	FCHK(fs->fs_cstotal.cs_ndir, >,
645 	    ((uint64_t)fs->fs_ipg * fs->fs_ncg) - fs->fs_cstotal.cs_nifree,
646 	    %jd);
647 	FCHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
648 	FCHK(fs->fs_sbsize, <, (signed)sizeof(struct fs), %jd);
649 	/* fix for misconfigured filesystems */
650 	if (fs->fs_maxbsize == 0)
651 		fs->fs_maxbsize = fs->fs_bsize;
652 	FCHK(fs->fs_maxbsize, <, fs->fs_bsize, %jd);
653 	FCHK(powerof2(fs->fs_maxbsize), ==, 0, %jd);
654 	FCHK(fs->fs_maxbsize, >, FS_MAXCONTIG * fs->fs_bsize, %jd);
655 	FCHK(fs->fs_bmask, !=, ~(fs->fs_bsize - 1), %#jx);
656 	FCHK(fs->fs_fmask, !=, ~(fs->fs_fsize - 1), %#jx);
657 	FCHK(fs->fs_qbmask, !=, ~fs->fs_bmask, %#jx);
658 	FCHK(fs->fs_qfmask, !=, ~fs->fs_fmask, %#jx);
659 	FCHK(fs->fs_bshift, !=, ILOG2(fs->fs_bsize), %jd);
660 	FCHK(fs->fs_fshift, !=, ILOG2(fs->fs_fsize), %jd);
661 	FCHK(fs->fs_fragshift, !=, ILOG2(fs->fs_frag), %jd);
662 	FCHK(fs->fs_fsbtodb, !=, ILOG2(fs->fs_fsize / sectorsize), %jd);
663 	FCHK(fs->fs_old_cgoffset, <, 0, %jd);
664 	FCHK2(fs->fs_old_cgoffset, >, 0, ~fs->fs_old_cgmask, <, 0, %jd);
665 	FCHK(fs->fs_old_cgoffset * (~fs->fs_old_cgmask), >, fs->fs_fpg, %jd);
666 	FCHK(CGSIZE(fs), >, fs->fs_bsize, %jd);
667 	/*
668 	 * If anything has failed up to this point, it is usafe to proceed
669 	 * as checks below may divide by zero or make other fatal calculations.
670 	 * So if we have any errors at this point, give up.
671 	 */
672 	if (error)
673 		return (error);
674 	FCHK(fs->fs_sbsize % sectorsize, !=, 0, %jd);
675 	FCHK(fs->fs_ipg % fs->fs_inopb, !=, 0, %jd);
676 	FCHK(fs->fs_sblkno, !=, roundup(
677 	    howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize),
678 	    fs->fs_frag), %jd);
679 	FCHK(fs->fs_cblkno, !=, fs->fs_sblkno +
680 	    roundup(howmany(SBLOCKSIZE, fs->fs_fsize), fs->fs_frag), %jd);
681 	FCHK(fs->fs_iblkno, !=, fs->fs_cblkno + fs->fs_frag, %jd);
682 	FCHK(fs->fs_dblkno, !=, fs->fs_iblkno + fs->fs_ipg / INOPF(fs), %jd);
683 	FCHK(fs->fs_cgsize, >, fs->fs_bsize, %jd);
684 	FCHK(fs->fs_cgsize, <, fs->fs_fsize, %jd);
685 	FCHK(fs->fs_cgsize % fs->fs_fsize, !=, 0, %jd);
686 	/*
687 	 * This test is valid, however older versions of growfs failed
688 	 * to correctly update fs_dsize so will fail this test. Thus we
689 	 * exclude it from the requirements.
690 	 */
691 #ifdef notdef
692 	WCHK(fs->fs_dsize, !=, fs->fs_size - fs->fs_sblkno -
693 		fs->fs_ncg * (fs->fs_dblkno - fs->fs_sblkno) -
694 		howmany(fs->fs_cssize, fs->fs_fsize), %jd);
695 #endif
696 	WCHK(fs->fs_metaspace, <, 0, %jd);
697 	WCHK(fs->fs_metaspace, >, fs->fs_fpg / 2, %jd);
698 	WCHK(fs->fs_minfree, >, 99, %jd%%);
699 	maxfilesize = fs->fs_bsize * UFS_NDADDR - 1;
700 	for (sizepb = fs->fs_bsize, i = 0; i < UFS_NIADDR; i++) {
701 		sizepb *= NINDIR(fs);
702 		maxfilesize += sizepb;
703 	}
704 	WCHK(fs->fs_maxfilesize, >, maxfilesize, %jd);
705 	/*
706 	 * These values have a tight interaction with each other that
707 	 * makes it hard to tightly bound them. So we can only check
708 	 * that they are within a broader possible range.
709 	 *
710 	 * The size cannot always be accurately determined, but ensure
711 	 * that it is consistent with the number of cylinder groups (fs_ncg)
712 	 * and the number of fragments per cylinder group (fs_fpg). Ensure
713 	 * that the summary information size is correct and that it starts
714 	 * and ends in the data area of the same cylinder group.
715 	 */
716 	FCHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
717 	FCHK(fs->fs_size, <=, ((int64_t)fs->fs_ncg - 1) * fs->fs_fpg, %jd);
718 	FCHK(fs->fs_size, >, (int64_t)fs->fs_ncg * fs->fs_fpg, %jd);
719 	/*
720 	 * If we are not requested to read in the csum data stop here
721 	 * as the correctness of the remaining values is only important
722 	 * to bound the space needed to be allocated to hold the csum data.
723 	 */
724 	if ((flags & UFS_NOCSUM) != 0)
725 		return (error);
726 	FCHK(fs->fs_csaddr, <, 0, %jd);
727 	FCHK(fs->fs_cssize, !=,
728 	    fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
729 	FCHK(fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize), >,
730 	    fs->fs_size, %jd);
731 	FCHK(fs->fs_csaddr, <, cgdmin(fs, dtog(fs, fs->fs_csaddr)), %jd);
732 	FCHK(dtog(fs, fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize)), >,
733 	    dtog(fs, fs->fs_csaddr), %jd);
734 	/*
735 	 * With file system clustering it is possible to allocate
736 	 * many contiguous blocks. The kernel variable maxphys defines
737 	 * the maximum transfer size permitted by the controller and/or
738 	 * buffering. The fs_maxcontig parameter controls the maximum
739 	 * number of blocks that the filesystem will read or write
740 	 * in a single transfer. It is calculated when the filesystem
741 	 * is created as maxphys / fs_bsize. The loader uses a maxphys
742 	 * of 128K even when running on a system that supports larger
743 	 * values. If the filesystem was built on a system that supports
744 	 * a larger maxphys (1M is typical) it will have configured
745 	 * fs_maxcontig for that larger system. So we bound the upper
746 	 * allowable limit for fs_maxconfig to be able to at least
747 	 * work with a 1M maxphys on the smallest block size filesystem:
748 	 * 1M / 4096 == 256. There is no harm in allowing the mounting of
749 	 * filesystems that make larger than maxphys I/O requests because
750 	 * those (mostly 32-bit machines) can (very slowly) handle I/O
751 	 * requests that exceed maxphys.
752 	 */
753 	WCHK(fs->fs_maxcontig, <, 0, %jd);
754 	WCHK(fs->fs_maxcontig, >, MAX(256, maxphys / fs->fs_bsize), %jd);
755 	FCHK2(fs->fs_maxcontig, ==, 0, fs->fs_contigsumsize, !=, 0, %jd);
756 	FCHK2(fs->fs_maxcontig, >, 1, fs->fs_contigsumsize, !=,
757 	    MIN(fs->fs_maxcontig, FS_MAXCONTIG), %jd);
758 	return (error);
759 }
760 
761 /*
762  * Make an extensive search to find a superblock. If the superblock
763  * in the standard place cannot be used, try looking for one of the
764  * backup superblocks.
765  *
766  * Flags are made up of the following or'ed together options:
767  *
768  * UFS_NOMSG indicates that superblock inconsistency error messages
769  *    should not be printed.
770  *
771  * UFS_NOCSUM causes only the superblock itself to be returned, but does
772  *    not read in any auxillary data structures like the cylinder group
773  *    summary information.
774  */
775 int
776 ffs_sbsearch(void *devfd, struct fs **fsp, int reqflags,
777     struct malloc_type *filltype,
778     int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
779 {
780 	struct fsrecovery *fsr;
781 	struct fs *protofs;
782 	void *fsrbuf;
783 	char *cp;
784 	long nocsum, flags, msg, cg;
785 	off_t sblk, secsize;
786 	int error;
787 
788 	msg = (reqflags & UFS_NOMSG) == 0;
789 	nocsum = reqflags & UFS_NOCSUM;
790 	/*
791 	 * Try normal superblock read and return it if it works.
792 	 *
793 	 * Suppress messages if it fails until we find out if
794 	 * failure can be avoided.
795 	 */
796 	flags = UFS_NOMSG | nocsum;
797 	error = ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc);
798 	/*
799 	 * If successful or endian error, no need to try further.
800 	 */
801 	if (error == 0 || error == EILSEQ) {
802 		if (msg && error == EILSEQ)
803 			printf("UFS superblock failed due to endian mismatch "
804 			    "between machine and filesystem\n");
805 		return (error);
806 	}
807 	/*
808 	 * First try: ignoring hash failures.
809 	 */
810 	flags |= UFS_NOHASHFAIL;
811 	if (msg)
812 		flags &= ~UFS_NOMSG;
813 	if (ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc) == 0)
814 		return (0);
815 	/*
816 	 * Next up is to check if fields of the superblock that are
817 	 * needed to find backup superblocks are usable.
818 	 */
819 	if (msg)
820 		printf("Attempted recovery for standard superblock: failed\n");
821 	flags = UFS_FSRONLY | UFS_NOHASHFAIL | UFS_NOCSUM | UFS_NOMSG;
822 	if (ffs_sbget(devfd, &protofs, UFS_STDSB, flags, filltype,
823 	    readfunc) == 0) {
824 		if (msg)
825 			printf("Attempt extraction of recovery data from "
826 			    "standard superblock.\n");
827 	} else {
828 		/*
829 		 * Final desperation is to see if alternate superblock
830 		 * parameters have been saved in the boot area.
831 		 */
832 		if (msg)
833 			printf("Attempted extraction of recovery data from "
834 			    "standard superblock: failed\nAttempt to find "
835 			    "boot zone recovery data.\n");
836 		/*
837 		 * Look to see if recovery information has been saved.
838 		 * If so we can generate a prototype superblock based
839 		 * on that information.
840 		 *
841 		 * We need fragments-per-group, number of cylinder groups,
842 		 * location of the superblock within the cylinder group, and
843 		 * the conversion from filesystem fragments to disk blocks.
844 		 *
845 		 * When building a UFS2 filesystem, newfs(8) stores these
846 		 * details at the end of the boot block area at the start
847 		 * of the filesystem partition. If they have been overwritten
848 		 * by a boot block, we fail.  But usually they are there
849 		 * and we can use them.
850 		 *
851 		 * We could ask the underlying device for its sector size,
852 		 * but some devices lie. So we just try a plausible range.
853 		 */
854 		error = ENOENT;
855 		fsrbuf = NULL;
856 		for (secsize = dbtob(1); secsize <= SBLOCKSIZE; secsize *= 2)
857 			if ((error = (*readfunc)(devfd, (SBLOCK_UFS2 - secsize),
858 			    &fsrbuf, secsize)) == 0)
859 				break;
860 		if (error != 0)
861 			goto trynowarn;
862 		cp = fsrbuf; /* type change to keep compiler happy */
863 		fsr = (struct fsrecovery *)&cp[secsize - sizeof *fsr];
864 		if (fsr->fsr_magic != FS_UFS2_MAGIC ||
865 		    (protofs = UFS_MALLOC(SBLOCKSIZE, filltype, M_NOWAIT))
866 		    == NULL) {
867 			UFS_FREE(fsrbuf, filltype);
868 			goto trynowarn;
869 		}
870 		memset(protofs, 0, sizeof(struct fs));
871 		protofs->fs_fpg = fsr->fsr_fpg;
872 		protofs->fs_fsbtodb = fsr->fsr_fsbtodb;
873 		protofs->fs_sblkno = fsr->fsr_sblkno;
874 		protofs->fs_magic = fsr->fsr_magic;
875 		protofs->fs_ncg = fsr->fsr_ncg;
876 		UFS_FREE(fsrbuf, filltype);
877 	}
878 	/*
879 	 * Scan looking for alternative superblocks.
880 	 */
881 	flags = nocsum;
882 	if (!msg)
883 		flags |= UFS_NOMSG;
884 	for (cg = 0; cg < protofs->fs_ncg; cg++) {
885 		sblk = fsbtodb(protofs, cgsblock(protofs, cg));
886 		if (msg)
887 			printf("Try cg %ld at sblock loc %jd\n", cg,
888 			    (intmax_t)sblk);
889 		if (ffs_sbget(devfd, fsp, dbtob(sblk), flags, filltype,
890 		    readfunc) == 0) {
891 			if (msg)
892 				printf("Succeeded with alternate superblock "
893 				    "at %jd\n", (intmax_t)sblk);
894 			UFS_FREE(protofs, filltype);
895 			return (0);
896 		}
897 	}
898 	UFS_FREE(protofs, filltype);
899 	/*
900 	 * Our alternate superblock strategies failed. Our last ditch effort
901 	 * is to see if the standard superblock has only non-critical errors.
902 	 */
903 trynowarn:
904 	flags = UFS_NOWARNFAIL | UFS_NOMSG | nocsum;
905 	if (msg) {
906 		printf("Finding an alternate superblock failed.\nCheck for "
907 		    "only non-critical errors in standard superblock\n");
908 		flags &= ~UFS_NOMSG;
909 	}
910 	if (ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc) != 0) {
911 		if (msg)
912 			printf("Failed, superblock has critical errors\n");
913 		return (ENOENT);
914 	}
915 	if (msg)
916 		printf("Success, using standard superblock with "
917 		    "non-critical errors.\n");
918 	return (0);
919 }
920 
921 /*
922  * Write a superblock to the devfd device from the memory pointed to by fs.
923  * Write out the superblock summary information if it is present.
924  *
925  * If the write is successful, zero is returned. Otherwise one of the
926  * following error values is returned:
927  *     EIO: failed to write superblock.
928  *     EIO: failed to write superblock summary information.
929  */
930 int
931 ffs_sbput(void *devfd, struct fs *fs, off_t loc,
932     int (*writefunc)(void *devfd, off_t loc, void *buf, int size))
933 {
934 	int i, error, blks, size;
935 	uint8_t *space;
936 
937 	/*
938 	 * If there is summary information, write it first, so if there
939 	 * is an error, the superblock will not be marked as clean.
940 	 */
941 	if (fs->fs_si != NULL && fs->fs_csp != NULL) {
942 		blks = howmany(fs->fs_cssize, fs->fs_fsize);
943 		space = (uint8_t *)fs->fs_csp;
944 		for (i = 0; i < blks; i += fs->fs_frag) {
945 			size = fs->fs_bsize;
946 			if (i + fs->fs_frag > blks)
947 				size = (blks - i) * fs->fs_fsize;
948 			if ((error = (*writefunc)(devfd,
949 			     dbtob(fsbtodb(fs, fs->fs_csaddr + i)),
950 			     space, size)) != 0)
951 				return (error);
952 			space += size;
953 		}
954 	}
955 	fs->fs_fmod = 0;
956 #ifndef _KERNEL
957 	{
958 		struct fs_summary_info *fs_si;
959 
960 		fs->fs_time = time(NULL);
961 		/* Clear the pointers for the duration of writing. */
962 		fs_si = fs->fs_si;
963 		fs->fs_si = NULL;
964 		fs->fs_ckhash = ffs_calc_sbhash(fs);
965 		error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize);
966 		fs->fs_si = fs_si;
967 	}
968 #else /* _KERNEL */
969 	fs->fs_time = time_second;
970 	fs->fs_ckhash = ffs_calc_sbhash(fs);
971 	error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize);
972 #endif /* _KERNEL */
973 	return (error);
974 }
975 
976 /*
977  * Calculate the check-hash for a superblock.
978  */
979 uint32_t
980 ffs_calc_sbhash(struct fs *fs)
981 {
982 	uint32_t ckhash, save_ckhash;
983 
984 	/*
985 	 * A filesystem that was using a superblock ckhash may be moved
986 	 * to an older kernel that does not support ckhashes. The
987 	 * older kernel will clear the FS_METACKHASH flag indicating
988 	 * that it does not update hashes. When the disk is moved back
989 	 * to a kernel capable of ckhashes it disables them on mount:
990 	 *
991 	 *	if ((fs->fs_flags & FS_METACKHASH) == 0)
992 	 *		fs->fs_metackhash = 0;
993 	 *
994 	 * This leaves (fs->fs_metackhash & CK_SUPERBLOCK) == 0) with an
995 	 * old stale value in the fs->fs_ckhash field. Thus the need to
996 	 * just accept what is there.
997 	 */
998 	if ((fs->fs_metackhash & CK_SUPERBLOCK) == 0)
999 		return (fs->fs_ckhash);
1000 
1001 	save_ckhash = fs->fs_ckhash;
1002 	fs->fs_ckhash = 0;
1003 	/*
1004 	 * If newly read from disk, the caller is responsible for
1005 	 * verifying that fs->fs_sbsize <= SBLOCKSIZE.
1006 	 */
1007 	ckhash = calculate_crc32c(~0L, (void *)fs, fs->fs_sbsize);
1008 	fs->fs_ckhash = save_ckhash;
1009 	return (ckhash);
1010 }
1011 
1012 /*
1013  * Update the frsum fields to reflect addition or deletion
1014  * of some frags.
1015  */
1016 void
1017 ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt)
1018 {
1019 	int inblk;
1020 	int field, subfield;
1021 	int siz, pos;
1022 
1023 	inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
1024 	fragmap <<= 1;
1025 	for (siz = 1; siz < fs->fs_frag; siz++) {
1026 		if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0)
1027 			continue;
1028 		field = around[siz];
1029 		subfield = inside[siz];
1030 		for (pos = siz; pos <= fs->fs_frag; pos++) {
1031 			if ((fragmap & field) == subfield) {
1032 				fraglist[siz] += cnt;
1033 				pos += siz;
1034 				field <<= siz;
1035 				subfield <<= siz;
1036 			}
1037 			field <<= 1;
1038 			subfield <<= 1;
1039 		}
1040 	}
1041 }
1042 
1043 /*
1044  * block operations
1045  *
1046  * check if a block is available
1047  */
1048 int
1049 ffs_isblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h)
1050 {
1051 	unsigned char mask;
1052 
1053 	switch ((int)fs->fs_frag) {
1054 	case 8:
1055 		return (cp[h] == 0xff);
1056 	case 4:
1057 		mask = 0x0f << ((h & 0x1) << 2);
1058 		return ((cp[h >> 1] & mask) == mask);
1059 	case 2:
1060 		mask = 0x03 << ((h & 0x3) << 1);
1061 		return ((cp[h >> 2] & mask) == mask);
1062 	case 1:
1063 		mask = 0x01 << (h & 0x7);
1064 		return ((cp[h >> 3] & mask) == mask);
1065 	default:
1066 #ifdef _KERNEL
1067 		panic("ffs_isblock");
1068 #endif
1069 		break;
1070 	}
1071 	return (0);
1072 }
1073 
1074 /*
1075  * check if a block is free
1076  */
1077 int
1078 ffs_isfreeblock(struct fs *fs, uint8_t *cp, ufs1_daddr_t h)
1079 {
1080 
1081 	switch ((int)fs->fs_frag) {
1082 	case 8:
1083 		return (cp[h] == 0);
1084 	case 4:
1085 		return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0);
1086 	case 2:
1087 		return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0);
1088 	case 1:
1089 		return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0);
1090 	default:
1091 #ifdef _KERNEL
1092 		panic("ffs_isfreeblock");
1093 #endif
1094 		break;
1095 	}
1096 	return (0);
1097 }
1098 
1099 /*
1100  * take a block out of the map
1101  */
1102 void
1103 ffs_clrblock(struct fs *fs, uint8_t *cp, ufs1_daddr_t h)
1104 {
1105 
1106 	switch ((int)fs->fs_frag) {
1107 	case 8:
1108 		cp[h] = 0;
1109 		return;
1110 	case 4:
1111 		cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
1112 		return;
1113 	case 2:
1114 		cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
1115 		return;
1116 	case 1:
1117 		cp[h >> 3] &= ~(0x01 << (h & 0x7));
1118 		return;
1119 	default:
1120 #ifdef _KERNEL
1121 		panic("ffs_clrblock");
1122 #endif
1123 		break;
1124 	}
1125 }
1126 
1127 /*
1128  * put a block into the map
1129  */
1130 void
1131 ffs_setblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h)
1132 {
1133 
1134 	switch ((int)fs->fs_frag) {
1135 	case 8:
1136 		cp[h] = 0xff;
1137 		return;
1138 	case 4:
1139 		cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
1140 		return;
1141 	case 2:
1142 		cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
1143 		return;
1144 	case 1:
1145 		cp[h >> 3] |= (0x01 << (h & 0x7));
1146 		return;
1147 	default:
1148 #ifdef _KERNEL
1149 		panic("ffs_setblock");
1150 #endif
1151 		break;
1152 	}
1153 }
1154 
1155 /*
1156  * Update the cluster map because of an allocation or free.
1157  *
1158  * Cnt == 1 means free; cnt == -1 means allocating.
1159  */
1160 void
1161 ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_daddr_t blkno, int cnt)
1162 {
1163 	int32_t *sump;
1164 	int32_t *lp;
1165 	uint8_t *freemapp, *mapp;
1166 	int i, start, end, forw, back, map;
1167 	uint64_t bit;
1168 
1169 	if (fs->fs_contigsumsize <= 0)
1170 		return;
1171 	freemapp = cg_clustersfree(cgp);
1172 	sump = cg_clustersum(cgp);
1173 	/*
1174 	 * Allocate or clear the actual block.
1175 	 */
1176 	if (cnt > 0)
1177 		setbit(freemapp, blkno);
1178 	else
1179 		clrbit(freemapp, blkno);
1180 	/*
1181 	 * Find the size of the cluster going forward.
1182 	 */
1183 	start = blkno + 1;
1184 	end = start + fs->fs_contigsumsize;
1185 	if (end >= cgp->cg_nclusterblks)
1186 		end = cgp->cg_nclusterblks;
1187 	mapp = &freemapp[start / NBBY];
1188 	map = *mapp++;
1189 	bit = 1U << (start % NBBY);
1190 	for (i = start; i < end; i++) {
1191 		if ((map & bit) == 0)
1192 			break;
1193 		if ((i & (NBBY - 1)) != (NBBY - 1)) {
1194 			bit <<= 1;
1195 		} else {
1196 			map = *mapp++;
1197 			bit = 1;
1198 		}
1199 	}
1200 	forw = i - start;
1201 	/*
1202 	 * Find the size of the cluster going backward.
1203 	 */
1204 	start = blkno - 1;
1205 	end = start - fs->fs_contigsumsize;
1206 	if (end < 0)
1207 		end = -1;
1208 	mapp = &freemapp[start / NBBY];
1209 	map = *mapp--;
1210 	bit = 1U << (start % NBBY);
1211 	for (i = start; i > end; i--) {
1212 		if ((map & bit) == 0)
1213 			break;
1214 		if ((i & (NBBY - 1)) != 0) {
1215 			bit >>= 1;
1216 		} else {
1217 			map = *mapp--;
1218 			bit = 1U << (NBBY - 1);
1219 		}
1220 	}
1221 	back = start - i;
1222 	/*
1223 	 * Account for old cluster and the possibly new forward and
1224 	 * back clusters.
1225 	 */
1226 	i = back + forw + 1;
1227 	if (i > fs->fs_contigsumsize)
1228 		i = fs->fs_contigsumsize;
1229 	sump[i] += cnt;
1230 	if (back > 0)
1231 		sump[back] -= cnt;
1232 	if (forw > 0)
1233 		sump[forw] -= cnt;
1234 	/*
1235 	 * Update cluster summary information.
1236 	 */
1237 	lp = &sump[fs->fs_contigsumsize];
1238 	for (i = fs->fs_contigsumsize; i > 0; i--)
1239 		if (*lp-- > 0)
1240 			break;
1241 	fs->fs_maxcluster[cgp->cg_cgx] = i;
1242 }
1243