xref: /freebsd/sys/ufs/ffs/ffs_subr.c (revision 6580f5c38dd5b01aeeaed16b370f1a12423437f0)
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 <stdio.h>
38 #include <string.h>
39 #include <stdlib.h>
40 #include <time.h>
41 #include <sys/errno.h>
42 #include <ufs/ufs/dinode.h>
43 #include <ufs/ffs/fs.h>
44 
45 uint32_t calculate_crc32c(uint32_t, const void *, size_t);
46 uint32_t ffs_calc_sbhash(struct fs *);
47 struct malloc_type;
48 #define UFS_MALLOC(size, type, flags) malloc(size)
49 #define UFS_FREE(ptr, type) free(ptr)
50 #define maxphys MAXPHYS
51 
52 #else /* _KERNEL */
53 #include <sys/systm.h>
54 #include <sys/gsb_crc32.h>
55 #include <sys/lock.h>
56 #include <sys/malloc.h>
57 #include <sys/mount.h>
58 #include <sys/vnode.h>
59 #include <sys/bio.h>
60 #include <sys/buf.h>
61 #include <sys/ucred.h>
62 
63 #include <ufs/ufs/quota.h>
64 #include <ufs/ufs/inode.h>
65 #include <ufs/ufs/extattr.h>
66 #include <ufs/ufs/ufsmount.h>
67 #include <ufs/ufs/ufs_extern.h>
68 #include <ufs/ffs/ffs_extern.h>
69 #include <ufs/ffs/fs.h>
70 
71 #define UFS_MALLOC(size, type, flags) malloc(size, type, flags)
72 #define UFS_FREE(ptr, type) free(ptr, type)
73 
74 #endif /* _KERNEL */
75 
76 /*
77  * Verify an inode check-hash.
78  */
79 int
80 ffs_verify_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip)
81 {
82 	uint32_t ckhash, save_ckhash;
83 
84 	/*
85 	 * Return success if unallocated or we are not doing inode check-hash.
86 	 */
87 	if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0)
88 		return (0);
89 	/*
90 	 * Exclude di_ckhash from the crc32 calculation, e.g., always use
91 	 * a check-hash value of zero when calculating the check-hash.
92 	 */
93 	save_ckhash = dip->di_ckhash;
94 	dip->di_ckhash = 0;
95 	ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip));
96 	dip->di_ckhash = save_ckhash;
97 	if (save_ckhash == ckhash)
98 		return (0);
99 	return (EINVAL);
100 }
101 
102 /*
103  * Update an inode check-hash.
104  */
105 void
106 ffs_update_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip)
107 {
108 
109 	if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0)
110 		return;
111 	/*
112 	 * Exclude old di_ckhash from the crc32 calculation, e.g., always use
113 	 * a check-hash value of zero when calculating the new check-hash.
114 	 */
115 	dip->di_ckhash = 0;
116 	dip->di_ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip));
117 }
118 
119 /*
120  * These are the low-level functions that actually read and write
121  * the superblock and its associated data.
122  */
123 static off_t sblock_try[] = SBLOCKSEARCH;
124 static int readsuper(void *, struct fs **, off_t, int,
125 	int (*)(void *, off_t, void **, int));
126 static int validate_sblock(struct fs *, int);
127 
128 /*
129  * Read a superblock from the devfd device.
130  *
131  * If an alternate superblock is specified, it is read. Otherwise the
132  * set of locations given in the SBLOCKSEARCH list is searched for a
133  * superblock. Memory is allocated for the superblock by the readfunc and
134  * is returned. If filltype is non-NULL, additional memory is allocated
135  * of type filltype and filled in with the superblock summary information.
136  * All memory is freed when any error is returned.
137  *
138  * If a superblock is found, zero is returned. Otherwise one of the
139  * following error values is returned:
140  *     EIO: non-existent or truncated superblock.
141  *     EIO: error reading summary information.
142  *     ENOENT: no usable known superblock found.
143  *     EILSEQ: filesystem with wrong byte order found.
144  *     ENOMEM: failed to allocate space for the superblock.
145  *     EINVAL: The previous newfs operation on this volume did not complete.
146  *         The administrator must complete newfs before using this volume.
147  */
148 int
149 ffs_sbget(void *devfd, struct fs **fsp, off_t sblock, int flags,
150     struct malloc_type *filltype,
151     int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
152 {
153 	struct fs *fs;
154 	struct fs_summary_info *fs_si;
155 	int i, error;
156 	uint64_t size, blks;
157 	uint8_t *space;
158 	int32_t *lp;
159 	char *buf;
160 
161 	fs = NULL;
162 	*fsp = NULL;
163 	if (sblock != UFS_STDSB) {
164 		if ((error = readsuper(devfd, &fs, sblock,
165 		    flags | UFS_ALTSBLK, readfunc)) != 0) {
166 			if (fs != NULL)
167 				UFS_FREE(fs, filltype);
168 			return (error);
169 		}
170 	} else {
171 		for (i = 0; sblock_try[i] != -1; i++) {
172 			if ((error = readsuper(devfd, &fs, sblock_try[i],
173 			     flags, readfunc)) == 0) {
174 				if ((flags & UFS_NOCSUM) != 0) {
175 					*fsp = fs;
176 					return (0);
177 				}
178 				break;
179 			}
180 			if (fs != NULL) {
181 				UFS_FREE(fs, filltype);
182 				fs = NULL;
183 			}
184 			if (error == ENOENT)
185 				continue;
186 			return (error);
187 		}
188 		if (sblock_try[i] == -1)
189 			return (ENOENT);
190 	}
191 	/*
192 	 * Read in the superblock summary information.
193 	 */
194 	size = fs->fs_cssize;
195 	blks = howmany(size, fs->fs_fsize);
196 	if (fs->fs_contigsumsize > 0)
197 		size += fs->fs_ncg * sizeof(int32_t);
198 	size += fs->fs_ncg * sizeof(uint8_t);
199 	if ((fs_si = UFS_MALLOC(sizeof(*fs_si), filltype, M_NOWAIT)) == NULL) {
200 		UFS_FREE(fs, filltype);
201 		return (ENOMEM);
202 	}
203 	bzero(fs_si, sizeof(*fs_si));
204 	fs->fs_si = fs_si;
205 	if ((space = UFS_MALLOC(size, filltype, M_NOWAIT)) == NULL) {
206 		UFS_FREE(fs->fs_si, filltype);
207 		UFS_FREE(fs, filltype);
208 		return (ENOMEM);
209 	}
210 	fs->fs_csp = (struct csum *)space;
211 	for (i = 0; i < blks; i += fs->fs_frag) {
212 		size = fs->fs_bsize;
213 		if (i + fs->fs_frag > blks)
214 			size = (blks - i) * fs->fs_fsize;
215 		buf = NULL;
216 		error = (*readfunc)(devfd,
217 		    dbtob(fsbtodb(fs, fs->fs_csaddr + i)), (void **)&buf, size);
218 		if (error) {
219 			if (buf != NULL)
220 				UFS_FREE(buf, filltype);
221 			UFS_FREE(fs->fs_csp, filltype);
222 			UFS_FREE(fs->fs_si, filltype);
223 			UFS_FREE(fs, filltype);
224 			return (error);
225 		}
226 		memcpy(space, buf, size);
227 		UFS_FREE(buf, filltype);
228 		space += size;
229 	}
230 	if (fs->fs_contigsumsize > 0) {
231 		fs->fs_maxcluster = lp = (int32_t *)space;
232 		for (i = 0; i < fs->fs_ncg; i++)
233 			*lp++ = fs->fs_contigsumsize;
234 		space = (uint8_t *)lp;
235 	}
236 	size = fs->fs_ncg * sizeof(uint8_t);
237 	fs->fs_contigdirs = (uint8_t *)space;
238 	bzero(fs->fs_contigdirs, size);
239 	*fsp = fs;
240 	return (0);
241 }
242 
243 /*
244  * Try to read a superblock from the location specified by sblockloc.
245  * Return zero on success or an errno on failure.
246  */
247 static int
248 readsuper(void *devfd, struct fs **fsp, off_t sblockloc, int flags,
249     int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
250 {
251 	struct fs *fs;
252 	int error, res;
253 	uint32_t ckhash;
254 
255 	error = (*readfunc)(devfd, sblockloc, (void **)fsp, SBLOCKSIZE);
256 	if (error != 0)
257 		return (error);
258 	fs = *fsp;
259 	if (fs->fs_magic == FS_BAD_MAGIC)
260 		return (EINVAL);
261 	/*
262 	 * For UFS1 with a 65536 block size, the first backup superblock
263 	 * is at the same location as the UFS2 superblock. Since SBLOCK_UFS2
264 	 * is the first location checked, the first backup is the superblock
265 	 * that will be accessed. Here we fail the lookup so that we can
266 	 * retry with the correct location for the UFS1 superblock.
267 	 */
268 	if (fs->fs_magic == FS_UFS1_MAGIC && (flags & UFS_ALTSBLK) == 0 &&
269 	    fs->fs_bsize == SBLOCK_UFS2 && sblockloc == SBLOCK_UFS2)
270 		return (ENOENT);
271 	if ((error = validate_sblock(fs, flags)) > 0)
272 		return (error);
273 	/*
274 	 * If the filesystem has been run on a kernel without
275 	 * metadata check hashes, disable them.
276 	 */
277 	if ((fs->fs_flags & FS_METACKHASH) == 0)
278 		fs->fs_metackhash = 0;
279 	/*
280 	 * Clear any check-hashes that are not maintained
281 	 * by this kernel. Also clear any unsupported flags.
282 	 */
283 	fs->fs_metackhash &= CK_SUPPORTED;
284 	fs->fs_flags &= FS_SUPPORTED;
285 	if (fs->fs_ckhash != (ckhash = ffs_calc_sbhash(fs))) {
286 		if ((flags & (UFS_NOMSG | UFS_NOHASHFAIL)) ==
287 		    (UFS_NOMSG | UFS_NOHASHFAIL))
288 			return (0);
289 		if ((flags & UFS_NOMSG) != 0)
290 			return (EINTEGRITY);
291 #ifdef _KERNEL
292 		res = uprintf("Superblock check-hash failed: recorded "
293 		    "check-hash 0x%x != computed check-hash 0x%x%s\n",
294 		    fs->fs_ckhash, ckhash,
295 		    (flags & UFS_NOHASHFAIL) != 0 ? " (Ignored)" : "");
296 #else
297 		res = 0;
298 #endif
299 		/*
300 		 * Print check-hash failure if no controlling terminal
301 		 * in kernel or always if in user-mode (libufs).
302 		 */
303 		if (res == 0)
304 			printf("Superblock check-hash failed: recorded "
305 			    "check-hash 0x%x != computed check-hash "
306 			    "0x%x%s\n", fs->fs_ckhash, ckhash,
307 			    (flags & UFS_NOHASHFAIL) ? " (Ignored)" : "");
308 		if ((flags & UFS_NOHASHFAIL) != 0)
309 			return (0);
310 		return (EINTEGRITY);
311 	}
312 	/* Have to set for old filesystems that predate this field */
313 	fs->fs_sblockactualloc = sblockloc;
314 	/* Not yet any summary information */
315 	fs->fs_si = NULL;
316 	return (0);
317 }
318 
319 /*
320  * Verify the filesystem values.
321  */
322 #define ILOG2(num)	(fls(num) - 1)
323 #ifdef STANDALONE_SMALL
324 #define MPRINT(...)	do { } while (0)
325 #else
326 #define MPRINT(...)	if (prtmsg) printf(__VA_ARGS__)
327 #endif
328 #define FCHK(lhs, op, rhs, fmt)						\
329 	if (lhs op rhs) {						\
330 		MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s ("	\
331 		    #fmt ")\n", fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2,	\
332 		    #lhs, (intmax_t)lhs, #op, #rhs, (intmax_t)rhs);	\
333 		if (error < 0)						\
334 			return (ENOENT);				\
335 		if (error == 0)						\
336 			error = ENOENT;					\
337 	}
338 #define WCHK(lhs, op, rhs, fmt)						\
339 	if (lhs op rhs) {						\
340 		MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s ("	\
341 		    #fmt ")%s\n", fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2,\
342 		    #lhs, (intmax_t)lhs, #op, #rhs, (intmax_t)rhs, wmsg);\
343 		if (error == 0)						\
344 			error = warnerr;				\
345 		if (warnerr == 0)					\
346 			lhs = rhs;					\
347 	}
348 #define FCHK2(lhs1, op1, rhs1, lhs2, op2, rhs2, fmt)			\
349 	if (lhs1 op1 rhs1 && lhs2 op2 rhs2) {				\
350 		MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s ("	\
351 		    #fmt ") && %s (" #fmt ") %s %s (" #fmt ")\n",	\
352 		    fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2, #lhs1,	\
353 		    (intmax_t)lhs1, #op1, #rhs1, (intmax_t)rhs1, #lhs2,	\
354 		    (intmax_t)lhs2, #op2, #rhs2, (intmax_t)rhs2);	\
355 		if (error < 0)						\
356 			return (ENOENT);				\
357 		if (error == 0)						\
358 			error = ENOENT;					\
359 	}
360 
361 static int
362 validate_sblock(struct fs *fs, int flags)
363 {
364 	uint64_t i, sectorsize;
365 	uint64_t maxfilesize, sizepb;
366 	int error, prtmsg, warnerr;
367 	char *wmsg;
368 
369 	error = 0;
370 	sectorsize = dbtob(1);
371 	prtmsg = ((flags & UFS_NOMSG) == 0);
372 	warnerr = (flags & UFS_NOWARNFAIL) == UFS_NOWARNFAIL ? 0 : ENOENT;
373 	wmsg = warnerr ? "" : " (Ignored)";
374 	/*
375 	 * Check for endian mismatch between machine and filesystem.
376 	 */
377 	if (((fs->fs_magic != FS_UFS2_MAGIC) &&
378 	    (bswap32(fs->fs_magic) == FS_UFS2_MAGIC)) ||
379 	    ((fs->fs_magic != FS_UFS1_MAGIC) &&
380 	    (bswap32(fs->fs_magic) == FS_UFS1_MAGIC))) {
381 		MPRINT("UFS superblock failed due to endian mismatch "
382 		    "between machine and filesystem\n");
383 		return(EILSEQ);
384 	}
385 	/*
386 	 * If just validating for recovery, then do just the minimal
387 	 * checks needed for the superblock fields needed to find
388 	 * alternate superblocks.
389 	 */
390 	if ((flags & UFS_FSRONLY) == UFS_FSRONLY &&
391 	    (fs->fs_magic == FS_UFS1_MAGIC || fs->fs_magic == FS_UFS2_MAGIC)) {
392 		error = -1; /* fail on first error */
393 		if (fs->fs_magic == FS_UFS2_MAGIC) {
394 			FCHK(fs->fs_sblockloc, !=, SBLOCK_UFS2, %#jx);
395 		} else if (fs->fs_magic == FS_UFS1_MAGIC) {
396 			FCHK(fs->fs_sblockloc, <, 0, %jd);
397 			FCHK(fs->fs_sblockloc, >, SBLOCK_UFS1, %jd);
398 		}
399 		FCHK(fs->fs_frag, <, 1, %jd);
400 		FCHK(fs->fs_frag, >, MAXFRAG, %jd);
401 		FCHK(fs->fs_bsize, <, MINBSIZE, %jd);
402 		FCHK(fs->fs_bsize, >, MAXBSIZE, %jd);
403 		FCHK(fs->fs_bsize, <, roundup(sizeof(struct fs), DEV_BSIZE),
404 		    %jd);
405 		FCHK(fs->fs_fsize, <, sectorsize, %jd);
406 		FCHK(fs->fs_fsize * fs->fs_frag, !=, fs->fs_bsize, %jd);
407 		FCHK(powerof2(fs->fs_fsize), ==, 0, %jd);
408 		FCHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
409 		FCHK(fs->fs_sbsize, <, (signed)sizeof(struct fs), %jd);
410 		FCHK(fs->fs_sbsize % sectorsize, !=, 0, %jd);
411 		FCHK(fs->fs_fpg, <, 3 * fs->fs_frag, %jd);
412 		FCHK(fs->fs_ncg, <, 1, %jd);
413 		FCHK(fs->fs_fsbtodb, !=, ILOG2(fs->fs_fsize / sectorsize), %jd);
414 		FCHK(fs->fs_old_cgoffset, <, 0, %jd);
415 		FCHK2(fs->fs_old_cgoffset, >, 0, ~fs->fs_old_cgmask, <, 0, %jd);
416 		FCHK(fs->fs_old_cgoffset * (~fs->fs_old_cgmask), >, fs->fs_fpg,
417 		    %jd);
418 		FCHK(fs->fs_sblkno, !=, roundup(
419 		    howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize),
420 		    fs->fs_frag), %jd);
421 		FCHK(CGSIZE(fs), >, fs->fs_bsize, %jd);
422 		/* Only need to validate these if reading in csum data */
423 		if ((flags & UFS_NOCSUM) != 0)
424 			return (error);
425 		FCHK((uint64_t)fs->fs_ipg * fs->fs_ncg, >,
426 		    (((int64_t)(1)) << 32) - INOPB(fs), %jd);
427 		FCHK(fs->fs_cstotal.cs_nifree, <, 0, %jd);
428 		FCHK(fs->fs_cstotal.cs_nifree, >,
429 		    (uint64_t)fs->fs_ipg * fs->fs_ncg, %jd);
430 		FCHK(fs->fs_cstotal.cs_ndir, >,
431 		    ((uint64_t)fs->fs_ipg * fs->fs_ncg) -
432 		    fs->fs_cstotal.cs_nifree, %jd);
433 		FCHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
434 		FCHK(fs->fs_size, <=, ((int64_t)fs->fs_ncg - 1) * fs->fs_fpg,
435 		    %jd);
436 		FCHK(fs->fs_size, >, (int64_t)fs->fs_ncg * fs->fs_fpg, %jd);
437 		FCHK(fs->fs_csaddr, <, 0, %jd);
438 		FCHK(fs->fs_cssize, !=,
439 		    fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
440 		FCHK(fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize), >,
441 		    fs->fs_size, %jd);
442 		FCHK(fs->fs_csaddr, <, cgdmin(fs, dtog(fs, fs->fs_csaddr)),
443 		    %jd);
444 		FCHK(dtog(fs, fs->fs_csaddr + howmany(fs->fs_cssize,
445 		    fs->fs_fsize)), >, dtog(fs, fs->fs_csaddr), %jd);
446 		return (error);
447 	}
448 	if (fs->fs_magic == FS_UFS2_MAGIC) {
449 		if ((flags & UFS_ALTSBLK) == 0)
450 			FCHK2(fs->fs_sblockactualloc, !=, SBLOCK_UFS2,
451 			    fs->fs_sblockactualloc, !=, 0, %jd);
452 		FCHK(fs->fs_sblockloc, !=, SBLOCK_UFS2, %#jx);
453 		FCHK(fs->fs_maxsymlinklen, !=, ((UFS_NDADDR + UFS_NIADDR) *
454 			sizeof(ufs2_daddr_t)), %jd);
455 		FCHK(fs->fs_nindir, !=, fs->fs_bsize / sizeof(ufs2_daddr_t),
456 		    %jd);
457 		FCHK(fs->fs_inopb, !=,
458 		    fs->fs_bsize / sizeof(struct ufs2_dinode), %jd);
459 	} else if (fs->fs_magic == FS_UFS1_MAGIC) {
460 		if ((flags & UFS_ALTSBLK) == 0)
461 			FCHK(fs->fs_sblockactualloc, >, SBLOCK_UFS1, %jd);
462 		FCHK(fs->fs_sblockloc, <, 0, %jd);
463 		FCHK(fs->fs_sblockloc, >, SBLOCK_UFS1, %jd);
464 		FCHK(fs->fs_nindir, !=, fs->fs_bsize / sizeof(ufs1_daddr_t),
465 		    %jd);
466 		FCHK(fs->fs_inopb, !=,
467 		    fs->fs_bsize / sizeof(struct ufs1_dinode), %jd);
468 		FCHK(fs->fs_maxsymlinklen, !=, ((UFS_NDADDR + UFS_NIADDR) *
469 			sizeof(ufs1_daddr_t)), %jd);
470 		WCHK(fs->fs_old_inodefmt, !=, FS_44INODEFMT, %jd);
471 		WCHK(fs->fs_old_rotdelay, !=, 0, %jd);
472 		WCHK(fs->fs_old_rps, !=, 60, %jd);
473 		WCHK(fs->fs_old_nspf, !=, fs->fs_fsize / sectorsize, %jd);
474 		WCHK(fs->fs_old_interleave, !=, 1, %jd);
475 		WCHK(fs->fs_old_trackskew, !=, 0, %jd);
476 		WCHK(fs->fs_old_cpc, !=, 0, %jd);
477 		WCHK(fs->fs_old_postblformat, !=, 1, %jd);
478 		FCHK(fs->fs_old_nrpos, !=, 1, %jd);
479 		WCHK(fs->fs_old_nsect, !=, fs->fs_old_spc, %jd);
480 		WCHK(fs->fs_old_npsect, !=, fs->fs_old_spc, %jd);
481 	} else {
482 		/* Bad magic number, so assume not a superblock */
483 		return (ENOENT);
484 	}
485 	FCHK(fs->fs_bsize, <, MINBSIZE, %jd);
486 	FCHK(fs->fs_bsize, >, MAXBSIZE, %jd);
487 	FCHK(fs->fs_bsize, <, roundup(sizeof(struct fs), DEV_BSIZE), %jd);
488 	FCHK(powerof2(fs->fs_bsize), ==, 0, %jd);
489 	FCHK(fs->fs_frag, <, 1, %jd);
490 	FCHK(fs->fs_frag, >, MAXFRAG, %jd);
491 	FCHK(fs->fs_frag, !=, numfrags(fs, fs->fs_bsize), %jd);
492 	FCHK(fs->fs_fsize, <, sectorsize, %jd);
493 	FCHK(fs->fs_fsize * fs->fs_frag, !=, fs->fs_bsize, %jd);
494 	FCHK(powerof2(fs->fs_fsize), ==, 0, %jd);
495 	FCHK(fs->fs_fpg, <, 3 * fs->fs_frag, %jd);
496 	FCHK(fs->fs_ncg, <, 1, %jd);
497 	FCHK(fs->fs_ipg, <, fs->fs_inopb, %jd);
498 	FCHK((uint64_t)fs->fs_ipg * fs->fs_ncg, >,
499 	    (((int64_t)(1)) << 32) - INOPB(fs), %jd);
500 	FCHK(fs->fs_cstotal.cs_nifree, <, 0, %jd);
501 	FCHK(fs->fs_cstotal.cs_nifree, >, (uint64_t)fs->fs_ipg * fs->fs_ncg,
502 	    %jd);
503 	FCHK(fs->fs_cstotal.cs_ndir, <, 0, %jd);
504 	FCHK(fs->fs_cstotal.cs_ndir, >,
505 	    ((uint64_t)fs->fs_ipg * fs->fs_ncg) - fs->fs_cstotal.cs_nifree,
506 	    %jd);
507 	FCHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
508 	FCHK(fs->fs_sbsize, <, (signed)sizeof(struct fs), %jd);
509 	/* fix for misconfigured filesystems */
510 	if (fs->fs_maxbsize == 0)
511 		fs->fs_maxbsize = fs->fs_bsize;
512 	FCHK(fs->fs_maxbsize, <, fs->fs_bsize, %jd);
513 	FCHK(powerof2(fs->fs_maxbsize), ==, 0, %jd);
514 	FCHK(fs->fs_maxbsize, >, FS_MAXCONTIG * fs->fs_bsize, %jd);
515 	FCHK(fs->fs_bmask, !=, ~(fs->fs_bsize - 1), %#jx);
516 	FCHK(fs->fs_fmask, !=, ~(fs->fs_fsize - 1), %#jx);
517 	FCHK(fs->fs_qbmask, !=, ~fs->fs_bmask, %#jx);
518 	FCHK(fs->fs_qfmask, !=, ~fs->fs_fmask, %#jx);
519 	FCHK(fs->fs_bshift, !=, ILOG2(fs->fs_bsize), %jd);
520 	FCHK(fs->fs_fshift, !=, ILOG2(fs->fs_fsize), %jd);
521 	FCHK(fs->fs_fragshift, !=, ILOG2(fs->fs_frag), %jd);
522 	FCHK(fs->fs_fsbtodb, !=, ILOG2(fs->fs_fsize / sectorsize), %jd);
523 	FCHK(fs->fs_old_cgoffset, <, 0, %jd);
524 	FCHK2(fs->fs_old_cgoffset, >, 0, ~fs->fs_old_cgmask, <, 0, %jd);
525 	FCHK(fs->fs_old_cgoffset * (~fs->fs_old_cgmask), >, fs->fs_fpg, %jd);
526 	FCHK(CGSIZE(fs), >, fs->fs_bsize, %jd);
527 	/*
528 	 * If anything has failed up to this point, it is usafe to proceed
529 	 * as checks below may divide by zero or make other fatal calculations.
530 	 * So if we have any errors at this point, give up.
531 	 */
532 	if (error)
533 		return (error);
534 	FCHK(fs->fs_sbsize % sectorsize, !=, 0, %jd);
535 	FCHK(fs->fs_ipg % fs->fs_inopb, !=, 0, %jd);
536 	FCHK(fs->fs_sblkno, !=, roundup(
537 	    howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize),
538 	    fs->fs_frag), %jd);
539 	FCHK(fs->fs_cblkno, !=, fs->fs_sblkno +
540 	    roundup(howmany(SBLOCKSIZE, fs->fs_fsize), fs->fs_frag), %jd);
541 	FCHK(fs->fs_iblkno, !=, fs->fs_cblkno + fs->fs_frag, %jd);
542 	FCHK(fs->fs_dblkno, !=, fs->fs_iblkno + fs->fs_ipg / INOPF(fs), %jd);
543 	FCHK(fs->fs_cgsize, >, fs->fs_bsize, %jd);
544 	FCHK(fs->fs_cgsize, <, fs->fs_fsize, %jd);
545 	FCHK(fs->fs_cgsize % fs->fs_fsize, !=, 0, %jd);
546 	/*
547 	 * This test is valid, however older versions of growfs failed
548 	 * to correctly update fs_dsize so will fail this test. Thus we
549 	 * exclude it from the requirements.
550 	 */
551 #ifdef notdef
552 	WCHK(fs->fs_dsize, !=, fs->fs_size - fs->fs_sblkno -
553 		fs->fs_ncg * (fs->fs_dblkno - fs->fs_sblkno) -
554 		howmany(fs->fs_cssize, fs->fs_fsize), %jd);
555 #endif
556 	WCHK(fs->fs_metaspace, <, 0, %jd);
557 	WCHK(fs->fs_metaspace, >, fs->fs_fpg / 2, %jd);
558 	WCHK(fs->fs_minfree, >, 99, %jd%%);
559 	maxfilesize = fs->fs_bsize * UFS_NDADDR - 1;
560 	for (sizepb = fs->fs_bsize, i = 0; i < UFS_NIADDR; i++) {
561 		sizepb *= NINDIR(fs);
562 		maxfilesize += sizepb;
563 	}
564 	WCHK(fs->fs_maxfilesize, !=, maxfilesize, %jd);
565 	/*
566 	 * These values have a tight interaction with each other that
567 	 * makes it hard to tightly bound them. So we can only check
568 	 * that they are within a broader possible range.
569 	 *
570 	 * The size cannot always be accurately determined, but ensure
571 	 * that it is consistent with the number of cylinder groups (fs_ncg)
572 	 * and the number of fragments per cylinder group (fs_fpg). Ensure
573 	 * that the summary information size is correct and that it starts
574 	 * and ends in the data area of the same cylinder group.
575 	 */
576 	FCHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
577 	FCHK(fs->fs_size, <=, ((int64_t)fs->fs_ncg - 1) * fs->fs_fpg, %jd);
578 	FCHK(fs->fs_size, >, (int64_t)fs->fs_ncg * fs->fs_fpg, %jd);
579 	/*
580 	 * If we are not requested to read in the csum data stop here
581 	 * as the correctness of the remaining values is only important
582 	 * to bound the space needed to be allocated to hold the csum data.
583 	 */
584 	if ((flags & UFS_NOCSUM) != 0)
585 		return (error);
586 	FCHK(fs->fs_csaddr, <, 0, %jd);
587 	FCHK(fs->fs_cssize, !=,
588 	    fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
589 	FCHK(fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize), >,
590 	    fs->fs_size, %jd);
591 	FCHK(fs->fs_csaddr, <, cgdmin(fs, dtog(fs, fs->fs_csaddr)), %jd);
592 	FCHK(dtog(fs, fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize)), >,
593 	    dtog(fs, fs->fs_csaddr), %jd);
594 	/*
595 	 * With file system clustering it is possible to allocate
596 	 * many contiguous blocks. The kernel variable maxphys defines
597 	 * the maximum transfer size permitted by the controller and/or
598 	 * buffering. The fs_maxcontig parameter controls the maximum
599 	 * number of blocks that the filesystem will read or write
600 	 * in a single transfer. It is calculated when the filesystem
601 	 * is created as maxphys / fs_bsize. The loader uses a maxphys
602 	 * of 128K even when running on a system that supports larger
603 	 * values. If the filesystem was built on a system that supports
604 	 * a larger maxphys (1M is typical) it will have configured
605 	 * fs_maxcontig for that larger system. So we bound the upper
606 	 * allowable limit for fs_maxconfig to be able to at least
607 	 * work with a 1M maxphys on the smallest block size filesystem:
608 	 * 1M / 4096 == 256. There is no harm in allowing the mounting of
609 	 * filesystems that make larger than maxphys I/O requests because
610 	 * those (mostly 32-bit machines) can (very slowly) handle I/O
611 	 * requests that exceed maxphys.
612 	 */
613 	WCHK(fs->fs_maxcontig, <, 0, %jd);
614 	WCHK(fs->fs_maxcontig, >, MAX(256, maxphys / fs->fs_bsize), %jd);
615 	FCHK2(fs->fs_maxcontig, ==, 0, fs->fs_contigsumsize, !=, 0, %jd);
616 	FCHK2(fs->fs_maxcontig, >, 1, fs->fs_contigsumsize, !=,
617 	    MIN(fs->fs_maxcontig, FS_MAXCONTIG), %jd);
618 	return (error);
619 }
620 
621 /*
622  * Make an extensive search to find a superblock. If the superblock
623  * in the standard place cannot be used, try looking for one of the
624  * backup superblocks.
625  *
626  * Flags are made up of the following or'ed together options:
627  *
628  * UFS_NOMSG indicates that superblock inconsistency error messages
629  *    should not be printed.
630  *
631  * UFS_NOCSUM causes only the superblock itself to be returned, but does
632  *    not read in any auxillary data structures like the cylinder group
633  *    summary information.
634  */
635 int
636 ffs_sbsearch(void *devfd, struct fs **fsp, int reqflags,
637     struct malloc_type *filltype,
638     int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
639 {
640 	struct fsrecovery *fsr;
641 	struct fs *protofs;
642 	void *fsrbuf;
643 	char *cp;
644 	long nocsum, flags, msg, cg;
645 	off_t sblk, secsize;
646 	int error;
647 
648 	msg = (reqflags & UFS_NOMSG) == 0;
649 	nocsum = reqflags & UFS_NOCSUM;
650 	/*
651 	 * Try normal superblock read and return it if it works.
652 	 *
653 	 * Suppress messages if it fails until we find out if
654 	 * failure can be avoided.
655 	 */
656 	flags = UFS_NOMSG | nocsum;
657 	error = ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc);
658 	/*
659 	 * If successful or endian error, no need to try further.
660 	 */
661 	if (error == 0 || error == EILSEQ) {
662 		if (msg && error == EILSEQ)
663 			printf("UFS superblock failed due to endian mismatch "
664 			    "between machine and filesystem\n");
665 		return (error);
666 	}
667 	/*
668 	 * First try: ignoring hash failures.
669 	 */
670 	flags |= UFS_NOHASHFAIL;
671 	if (msg)
672 		flags &= ~UFS_NOMSG;
673 	if (ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc) == 0)
674 		return (0);
675 	/*
676 	 * Next up is to check if fields of the superblock that are
677 	 * needed to find backup superblocks are usable.
678 	 */
679 	if (msg)
680 		printf("Attempted recovery for standard superblock: failed\n");
681 	flags = UFS_FSRONLY | UFS_NOHASHFAIL | UFS_NOCSUM | UFS_NOMSG;
682 	if (ffs_sbget(devfd, &protofs, UFS_STDSB, flags, filltype,
683 	    readfunc) == 0) {
684 		if (msg)
685 			printf("Attempt extraction of recovery data from "
686 			    "standard superblock.\n");
687 	} else {
688 		/*
689 		 * Final desperation is to see if alternate superblock
690 		 * parameters have been saved in the boot area.
691 		 */
692 		if (msg)
693 			printf("Attempted extraction of recovery data from "
694 			    "standard superblock: failed\nAttempt to find "
695 			    "boot zone recovery data.\n");
696 		/*
697 		 * Look to see if recovery information has been saved.
698 		 * If so we can generate a prototype superblock based
699 		 * on that information.
700 		 *
701 		 * We need fragments-per-group, number of cylinder groups,
702 		 * location of the superblock within the cylinder group, and
703 		 * the conversion from filesystem fragments to disk blocks.
704 		 *
705 		 * When building a UFS2 filesystem, newfs(8) stores these
706 		 * details at the end of the boot block area at the start
707 		 * of the filesystem partition. If they have been overwritten
708 		 * by a boot block, we fail.  But usually they are there
709 		 * and we can use them.
710 		 *
711 		 * We could ask the underlying device for its sector size,
712 		 * but some devices lie. So we just try a plausible range.
713 		 */
714 		error = ENOENT;
715 		fsrbuf = NULL;
716 		for (secsize = dbtob(1); secsize <= SBLOCKSIZE; secsize *= 2)
717 			if ((error = (*readfunc)(devfd, (SBLOCK_UFS2 - secsize),
718 			    &fsrbuf, secsize)) == 0)
719 				break;
720 		if (error != 0)
721 			goto trynowarn;
722 		cp = fsrbuf; /* type change to keep compiler happy */
723 		fsr = (struct fsrecovery *)&cp[secsize - sizeof *fsr];
724 		if (fsr->fsr_magic != FS_UFS2_MAGIC ||
725 		    (protofs = UFS_MALLOC(SBLOCKSIZE, filltype, M_NOWAIT))
726 		    == NULL) {
727 			UFS_FREE(fsrbuf, filltype);
728 			goto trynowarn;
729 		}
730 		memset(protofs, 0, sizeof(struct fs));
731 		protofs->fs_fpg = fsr->fsr_fpg;
732 		protofs->fs_fsbtodb = fsr->fsr_fsbtodb;
733 		protofs->fs_sblkno = fsr->fsr_sblkno;
734 		protofs->fs_magic = fsr->fsr_magic;
735 		protofs->fs_ncg = fsr->fsr_ncg;
736 		UFS_FREE(fsrbuf, filltype);
737 	}
738 	/*
739 	 * Scan looking for alternative superblocks.
740 	 */
741 	flags = nocsum;
742 	if (!msg)
743 		flags |= UFS_NOMSG;
744 	for (cg = 0; cg < protofs->fs_ncg; cg++) {
745 		sblk = fsbtodb(protofs, cgsblock(protofs, cg));
746 		if (msg)
747 			printf("Try cg %ld at sblock loc %jd\n", cg,
748 			    (intmax_t)sblk);
749 		if (ffs_sbget(devfd, fsp, dbtob(sblk), flags, filltype,
750 		    readfunc) == 0) {
751 			if (msg)
752 				printf("Succeeded with alternate superblock "
753 				    "at %jd\n", (intmax_t)sblk);
754 			UFS_FREE(protofs, filltype);
755 			return (0);
756 		}
757 	}
758 	UFS_FREE(protofs, filltype);
759 	/*
760 	 * Our alternate superblock strategies failed. Our last ditch effort
761 	 * is to see if the standard superblock has only non-critical errors.
762 	 */
763 trynowarn:
764 	flags = UFS_NOWARNFAIL | UFS_NOMSG | nocsum;
765 	if (msg) {
766 		printf("Finding an alternate superblock failed.\nCheck for "
767 		    "only non-critical errors in standard superblock\n");
768 		flags &= ~UFS_NOMSG;
769 	}
770 	if (ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc) != 0) {
771 		if (msg)
772 			printf("Failed, superblock has critical errors\n");
773 		return (ENOENT);
774 	}
775 	if (msg)
776 		printf("Success, using standard superblock with "
777 		    "non-critical errors.\n");
778 	return (0);
779 }
780 
781 /*
782  * Write a superblock to the devfd device from the memory pointed to by fs.
783  * Write out the superblock summary information if it is present.
784  *
785  * If the write is successful, zero is returned. Otherwise one of the
786  * following error values is returned:
787  *     EIO: failed to write superblock.
788  *     EIO: failed to write superblock summary information.
789  */
790 int
791 ffs_sbput(void *devfd, struct fs *fs, off_t loc,
792     int (*writefunc)(void *devfd, off_t loc, void *buf, int size))
793 {
794 	int i, error, blks, size;
795 	uint8_t *space;
796 
797 	/*
798 	 * If there is summary information, write it first, so if there
799 	 * is an error, the superblock will not be marked as clean.
800 	 */
801 	if (fs->fs_si != NULL && fs->fs_csp != NULL) {
802 		blks = howmany(fs->fs_cssize, fs->fs_fsize);
803 		space = (uint8_t *)fs->fs_csp;
804 		for (i = 0; i < blks; i += fs->fs_frag) {
805 			size = fs->fs_bsize;
806 			if (i + fs->fs_frag > blks)
807 				size = (blks - i) * fs->fs_fsize;
808 			if ((error = (*writefunc)(devfd,
809 			     dbtob(fsbtodb(fs, fs->fs_csaddr + i)),
810 			     space, size)) != 0)
811 				return (error);
812 			space += size;
813 		}
814 	}
815 	fs->fs_fmod = 0;
816 #ifndef _KERNEL
817 	{
818 		struct fs_summary_info *fs_si;
819 
820 		fs->fs_time = time(NULL);
821 		/* Clear the pointers for the duration of writing. */
822 		fs_si = fs->fs_si;
823 		fs->fs_si = NULL;
824 		fs->fs_ckhash = ffs_calc_sbhash(fs);
825 		error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize);
826 		fs->fs_si = fs_si;
827 	}
828 #else /* _KERNEL */
829 	fs->fs_time = time_second;
830 	fs->fs_ckhash = ffs_calc_sbhash(fs);
831 	error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize);
832 #endif /* _KERNEL */
833 	return (error);
834 }
835 
836 /*
837  * Calculate the check-hash for a superblock.
838  */
839 uint32_t
840 ffs_calc_sbhash(struct fs *fs)
841 {
842 	uint32_t ckhash, save_ckhash;
843 
844 	/*
845 	 * A filesystem that was using a superblock ckhash may be moved
846 	 * to an older kernel that does not support ckhashes. The
847 	 * older kernel will clear the FS_METACKHASH flag indicating
848 	 * that it does not update hashes. When the disk is moved back
849 	 * to a kernel capable of ckhashes it disables them on mount:
850 	 *
851 	 *	if ((fs->fs_flags & FS_METACKHASH) == 0)
852 	 *		fs->fs_metackhash = 0;
853 	 *
854 	 * This leaves (fs->fs_metackhash & CK_SUPERBLOCK) == 0) with an
855 	 * old stale value in the fs->fs_ckhash field. Thus the need to
856 	 * just accept what is there.
857 	 */
858 	if ((fs->fs_metackhash & CK_SUPERBLOCK) == 0)
859 		return (fs->fs_ckhash);
860 
861 	save_ckhash = fs->fs_ckhash;
862 	fs->fs_ckhash = 0;
863 	/*
864 	 * If newly read from disk, the caller is responsible for
865 	 * verifying that fs->fs_sbsize <= SBLOCKSIZE.
866 	 */
867 	ckhash = calculate_crc32c(~0L, (void *)fs, fs->fs_sbsize);
868 	fs->fs_ckhash = save_ckhash;
869 	return (ckhash);
870 }
871 
872 /*
873  * Update the frsum fields to reflect addition or deletion
874  * of some frags.
875  */
876 void
877 ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt)
878 {
879 	int inblk;
880 	int field, subfield;
881 	int siz, pos;
882 
883 	inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
884 	fragmap <<= 1;
885 	for (siz = 1; siz < fs->fs_frag; siz++) {
886 		if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0)
887 			continue;
888 		field = around[siz];
889 		subfield = inside[siz];
890 		for (pos = siz; pos <= fs->fs_frag; pos++) {
891 			if ((fragmap & field) == subfield) {
892 				fraglist[siz] += cnt;
893 				pos += siz;
894 				field <<= siz;
895 				subfield <<= siz;
896 			}
897 			field <<= 1;
898 			subfield <<= 1;
899 		}
900 	}
901 }
902 
903 /*
904  * block operations
905  *
906  * check if a block is available
907  */
908 int
909 ffs_isblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h)
910 {
911 	unsigned char mask;
912 
913 	switch ((int)fs->fs_frag) {
914 	case 8:
915 		return (cp[h] == 0xff);
916 	case 4:
917 		mask = 0x0f << ((h & 0x1) << 2);
918 		return ((cp[h >> 1] & mask) == mask);
919 	case 2:
920 		mask = 0x03 << ((h & 0x3) << 1);
921 		return ((cp[h >> 2] & mask) == mask);
922 	case 1:
923 		mask = 0x01 << (h & 0x7);
924 		return ((cp[h >> 3] & mask) == mask);
925 	default:
926 #ifdef _KERNEL
927 		panic("ffs_isblock");
928 #endif
929 		break;
930 	}
931 	return (0);
932 }
933 
934 /*
935  * check if a block is free
936  */
937 int
938 ffs_isfreeblock(struct fs *fs, uint8_t *cp, ufs1_daddr_t h)
939 {
940 
941 	switch ((int)fs->fs_frag) {
942 	case 8:
943 		return (cp[h] == 0);
944 	case 4:
945 		return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0);
946 	case 2:
947 		return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0);
948 	case 1:
949 		return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0);
950 	default:
951 #ifdef _KERNEL
952 		panic("ffs_isfreeblock");
953 #endif
954 		break;
955 	}
956 	return (0);
957 }
958 
959 /*
960  * take a block out of the map
961  */
962 void
963 ffs_clrblock(struct fs *fs, uint8_t *cp, ufs1_daddr_t h)
964 {
965 
966 	switch ((int)fs->fs_frag) {
967 	case 8:
968 		cp[h] = 0;
969 		return;
970 	case 4:
971 		cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
972 		return;
973 	case 2:
974 		cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
975 		return;
976 	case 1:
977 		cp[h >> 3] &= ~(0x01 << (h & 0x7));
978 		return;
979 	default:
980 #ifdef _KERNEL
981 		panic("ffs_clrblock");
982 #endif
983 		break;
984 	}
985 }
986 
987 /*
988  * put a block into the map
989  */
990 void
991 ffs_setblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h)
992 {
993 
994 	switch ((int)fs->fs_frag) {
995 	case 8:
996 		cp[h] = 0xff;
997 		return;
998 	case 4:
999 		cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
1000 		return;
1001 	case 2:
1002 		cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
1003 		return;
1004 	case 1:
1005 		cp[h >> 3] |= (0x01 << (h & 0x7));
1006 		return;
1007 	default:
1008 #ifdef _KERNEL
1009 		panic("ffs_setblock");
1010 #endif
1011 		break;
1012 	}
1013 }
1014 
1015 /*
1016  * Update the cluster map because of an allocation or free.
1017  *
1018  * Cnt == 1 means free; cnt == -1 means allocating.
1019  */
1020 void
1021 ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_daddr_t blkno, int cnt)
1022 {
1023 	int32_t *sump;
1024 	int32_t *lp;
1025 	uint8_t *freemapp, *mapp;
1026 	int i, start, end, forw, back, map;
1027 	uint64_t bit;
1028 
1029 	if (fs->fs_contigsumsize <= 0)
1030 		return;
1031 	freemapp = cg_clustersfree(cgp);
1032 	sump = cg_clustersum(cgp);
1033 	/*
1034 	 * Allocate or clear the actual block.
1035 	 */
1036 	if (cnt > 0)
1037 		setbit(freemapp, blkno);
1038 	else
1039 		clrbit(freemapp, blkno);
1040 	/*
1041 	 * Find the size of the cluster going forward.
1042 	 */
1043 	start = blkno + 1;
1044 	end = start + fs->fs_contigsumsize;
1045 	if (end >= cgp->cg_nclusterblks)
1046 		end = cgp->cg_nclusterblks;
1047 	mapp = &freemapp[start / NBBY];
1048 	map = *mapp++;
1049 	bit = 1U << (start % NBBY);
1050 	for (i = start; i < end; i++) {
1051 		if ((map & bit) == 0)
1052 			break;
1053 		if ((i & (NBBY - 1)) != (NBBY - 1)) {
1054 			bit <<= 1;
1055 		} else {
1056 			map = *mapp++;
1057 			bit = 1;
1058 		}
1059 	}
1060 	forw = i - start;
1061 	/*
1062 	 * Find the size of the cluster going backward.
1063 	 */
1064 	start = blkno - 1;
1065 	end = start - fs->fs_contigsumsize;
1066 	if (end < 0)
1067 		end = -1;
1068 	mapp = &freemapp[start / NBBY];
1069 	map = *mapp--;
1070 	bit = 1U << (start % NBBY);
1071 	for (i = start; i > end; i--) {
1072 		if ((map & bit) == 0)
1073 			break;
1074 		if ((i & (NBBY - 1)) != 0) {
1075 			bit >>= 1;
1076 		} else {
1077 			map = *mapp--;
1078 			bit = 1U << (NBBY - 1);
1079 		}
1080 	}
1081 	back = start - i;
1082 	/*
1083 	 * Account for old cluster and the possibly new forward and
1084 	 * back clusters.
1085 	 */
1086 	i = back + forw + 1;
1087 	if (i > fs->fs_contigsumsize)
1088 		i = fs->fs_contigsumsize;
1089 	sump[i] += cnt;
1090 	if (back > 0)
1091 		sump[back] -= cnt;
1092 	if (forw > 0)
1093 		sump[forw] -= cnt;
1094 	/*
1095 	 * Update cluster summary information.
1096 	 */
1097 	lp = &sump[fs->fs_contigsumsize];
1098 	for (i = fs->fs_contigsumsize; i > 0; i--)
1099 		if (*lp-- > 0)
1100 			break;
1101 	fs->fs_maxcluster[cgp->cg_cgx] = i;
1102 }
1103