xref: /freebsd/sys/ufs/ffs/ffs_subr.c (revision 287d467c5db5a46f13566a2f9dae80a695335c73)
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  *	@(#)ffs_subr.c	8.5 (Berkeley) 3/21/95
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/limits.h>
39 
40 #ifndef _KERNEL
41 #include <stdio.h>
42 #include <string.h>
43 #include <stdlib.h>
44 #include <time.h>
45 #include <sys/errno.h>
46 #include <ufs/ufs/dinode.h>
47 #include <ufs/ffs/fs.h>
48 
49 uint32_t calculate_crc32c(uint32_t, const void *, size_t);
50 uint32_t ffs_calc_sbhash(struct fs *);
51 struct malloc_type;
52 #define UFS_MALLOC(size, type, flags) malloc(size)
53 #define UFS_FREE(ptr, type) free(ptr)
54 #define maxphys MAXPHYS
55 
56 #else /* _KERNEL */
57 #include <sys/systm.h>
58 #include <sys/gsb_crc32.h>
59 #include <sys/lock.h>
60 #include <sys/malloc.h>
61 #include <sys/mount.h>
62 #include <sys/vnode.h>
63 #include <sys/bio.h>
64 #include <sys/buf.h>
65 #include <sys/ucred.h>
66 
67 #include <ufs/ufs/quota.h>
68 #include <ufs/ufs/inode.h>
69 #include <ufs/ufs/extattr.h>
70 #include <ufs/ufs/ufsmount.h>
71 #include <ufs/ufs/ufs_extern.h>
72 #include <ufs/ffs/ffs_extern.h>
73 #include <ufs/ffs/fs.h>
74 
75 #define UFS_MALLOC(size, type, flags) malloc(size, type, flags)
76 #define UFS_FREE(ptr, type) free(ptr, type)
77 
78 #endif /* _KERNEL */
79 
80 /*
81  * Verify an inode check-hash.
82  */
83 int
84 ffs_verify_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip)
85 {
86 	uint32_t ckhash, save_ckhash;
87 
88 	/*
89 	 * Return success if unallocated or we are not doing inode check-hash.
90 	 */
91 	if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0)
92 		return (0);
93 	/*
94 	 * Exclude di_ckhash from the crc32 calculation, e.g., always use
95 	 * a check-hash value of zero when calculating the check-hash.
96 	 */
97 	save_ckhash = dip->di_ckhash;
98 	dip->di_ckhash = 0;
99 	ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip));
100 	dip->di_ckhash = save_ckhash;
101 	if (save_ckhash == ckhash)
102 		return (0);
103 	return (EINVAL);
104 }
105 
106 /*
107  * Update an inode check-hash.
108  */
109 void
110 ffs_update_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip)
111 {
112 
113 	if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0)
114 		return;
115 	/*
116 	 * Exclude old di_ckhash from the crc32 calculation, e.g., always use
117 	 * a check-hash value of zero when calculating the new check-hash.
118 	 */
119 	dip->di_ckhash = 0;
120 	dip->di_ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip));
121 }
122 
123 /*
124  * These are the low-level functions that actually read and write
125  * the superblock and its associated data.
126  */
127 static off_t sblock_try[] = SBLOCKSEARCH;
128 static int readsuper(void *, struct fs **, off_t, int, int,
129 	int (*)(void *, off_t, void **, int));
130 static int validate_sblock(struct fs *, int);
131 
132 /*
133  * Read a superblock from the devfd device.
134  *
135  * If an alternate superblock is specified, it is read. Otherwise the
136  * set of locations given in the SBLOCKSEARCH list is searched for a
137  * superblock. Memory is allocated for the superblock by the readfunc and
138  * is returned. If filltype is non-NULL, additional memory is allocated
139  * of type filltype and filled in with the superblock summary information.
140  * All memory is freed when any error is returned.
141  *
142  * If a superblock is found, zero is returned. Otherwise one of the
143  * following error values is returned:
144  *     EIO: non-existent or truncated superblock.
145  *     EIO: error reading summary information.
146  *     ENOENT: no usable known superblock 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 altsblock,
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 (altsblock >= 0) {
167 		if ((error = readsuper(devfd, &fs, altsblock, 1, 0,
168 		     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], 0,
176 			     altsblock, readfunc)) == 0)
177 				break;
178 			if (fs != NULL) {
179 				UFS_FREE(fs, filltype);
180 				fs = NULL;
181 			}
182 			if (error == ENOENT)
183 				continue;
184 			return (error);
185 		}
186 		if (sblock_try[i] == -1)
187 			return (ENOENT);
188 	}
189 	/*
190 	 * Read in the superblock summary information.
191 	 */
192 	size = fs->fs_cssize;
193 	blks = howmany(size, fs->fs_fsize);
194 	if (fs->fs_contigsumsize > 0)
195 		size += fs->fs_ncg * sizeof(int32_t);
196 	size += fs->fs_ncg * sizeof(u_int8_t);
197 	if ((fs_si = UFS_MALLOC(sizeof(*fs_si), filltype, M_NOWAIT)) == NULL) {
198 		UFS_FREE(fs, filltype);
199 		return (ENOMEM);
200 	}
201 	bzero(fs_si, sizeof(*fs_si));
202 	fs->fs_si = fs_si;
203 	if ((space = UFS_MALLOC(size, filltype, M_NOWAIT)) == NULL) {
204 		UFS_FREE(fs->fs_si, filltype);
205 		UFS_FREE(fs, filltype);
206 		return (ENOMEM);
207 	}
208 	fs->fs_csp = (struct csum *)space;
209 	for (i = 0; i < blks; i += fs->fs_frag) {
210 		size = fs->fs_bsize;
211 		if (i + fs->fs_frag > blks)
212 			size = (blks - i) * fs->fs_fsize;
213 		buf = NULL;
214 		error = (*readfunc)(devfd,
215 		    dbtob(fsbtodb(fs, fs->fs_csaddr + i)), (void **)&buf, size);
216 		if (error) {
217 			if (buf != NULL)
218 				UFS_FREE(buf, filltype);
219 			UFS_FREE(fs->fs_csp, filltype);
220 			UFS_FREE(fs->fs_si, filltype);
221 			UFS_FREE(fs, filltype);
222 			return (error);
223 		}
224 		memcpy(space, buf, size);
225 		UFS_FREE(buf, filltype);
226 		space += size;
227 	}
228 	if (fs->fs_contigsumsize > 0) {
229 		fs->fs_maxcluster = lp = (int32_t *)space;
230 		for (i = 0; i < fs->fs_ncg; i++)
231 			*lp++ = fs->fs_contigsumsize;
232 		space = (uint8_t *)lp;
233 	}
234 	size = fs->fs_ncg * sizeof(u_int8_t);
235 	fs->fs_contigdirs = (u_int8_t *)space;
236 	bzero(fs->fs_contigdirs, size);
237 	*fsp = fs;
238 	return (0);
239 }
240 
241 /*
242  * Try to read a superblock from the location specified by sblockloc.
243  * Return zero on success or an errno on failure.
244  */
245 static int
246 readsuper(void *devfd, struct fs **fsp, off_t sblockloc, int isaltsblk,
247     int chkhash, int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
248 {
249 	struct fs *fs;
250 	int error, res;
251 	uint32_t ckhash;
252 
253 	error = (*readfunc)(devfd, sblockloc, (void **)fsp, SBLOCKSIZE);
254 	if (error != 0)
255 		return (error);
256 	fs = *fsp;
257 	if (fs->fs_magic == FS_BAD_MAGIC)
258 		return (EINVAL);
259 	if ((error = validate_sblock(fs, isaltsblk)) != 0)
260 		return (error);
261 	/*
262 	 * If the filesystem has been run on a kernel without
263 	 * metadata check hashes, disable them.
264 	 */
265 	if ((fs->fs_flags & FS_METACKHASH) == 0)
266 		fs->fs_metackhash = 0;
267 	/*
268 	 * Clear any check-hashes that are not maintained
269 	 * by this kernel. Also clear any unsupported flags.
270 	 */
271 	fs->fs_metackhash &= CK_SUPPORTED;
272 	fs->fs_flags &= FS_SUPPORTED;
273 	if (fs->fs_ckhash != (ckhash = ffs_calc_sbhash(fs))) {
274 		if (chkhash == STDSB_NOMSG)
275 			return (EINTEGRITY);
276 		if (chkhash == STDSB_NOHASHFAIL_NOMSG)
277 			return (0);
278 #ifdef _KERNEL
279 		res = uprintf("Superblock check-hash failed: recorded "
280 		    "check-hash 0x%x != computed check-hash 0x%x%s\n",
281 		    fs->fs_ckhash, ckhash,
282 		    chkhash == STDSB_NOHASHFAIL ? " (Ignored)" : "");
283 #else
284 		res = 0;
285 #endif
286 		/*
287 		 * Print check-hash failure if no controlling terminal
288 		 * in kernel or always if in user-mode (libufs).
289 		 */
290 		if (res == 0)
291 			printf("Superblock check-hash failed: recorded "
292 			    "check-hash 0x%x != computed check-hash "
293 			    "0x%x%s\n", fs->fs_ckhash, ckhash,
294 			    chkhash == STDSB_NOHASHFAIL ?
295 			    " (Ignored)" : "");
296 		if (chkhash == STDSB)
297 			return (EINTEGRITY);
298 		/* chkhash == STDSB_NOHASHFAIL */
299 		return (0);
300 	}
301 	/* Have to set for old filesystems that predate this field */
302 	fs->fs_sblockactualloc = sblockloc;
303 	/* Not yet any summary information */
304 	fs->fs_si = NULL;
305 	return (0);
306 }
307 
308 /*
309  * Verify the filesystem values.
310  */
311 #define ILOG2(num) (fls(num) - 1)
312 #undef CHK
313 #define CHK(lhs, op, rhs, fmt)						\
314 	if (lhs op rhs) {						\
315 		printf("UFS%d superblock failed: %s (" #fmt ") %s %s ("	\
316 		    #fmt ")\n", fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2,	\
317 		    #lhs, (intmax_t)lhs, #op, #rhs, (intmax_t)rhs);	\
318 		return (ENOENT);					\
319 	}
320 #define CHK2(lhs1, op1, rhs1, lhs2, op2, rhs2, fmt)			\
321 	if (lhs1 op1 rhs1 && lhs2 op2 rhs2) {				\
322 		printf("UFS%d superblock failed: %s (" #fmt ") %s %s ("	\
323 		    #fmt ") && %s (" #fmt ") %s %s (" #fmt ")\n",	\
324 		    fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2, #lhs1, 	\
325 		    (intmax_t)lhs1, #op1, #rhs1, (intmax_t)rhs1, #lhs2,	\
326 		    (intmax_t)lhs2, #op2, #rhs2, (intmax_t)rhs2);	\
327 		return (ENOENT);					\
328 	}
329 
330 static int
331 validate_sblock(struct fs *fs, int isaltsblk)
332 {
333 	u_long i, sectorsize, cgnum;
334 	u_int64_t maxfilesize, sizepb;
335 
336 	sectorsize = dbtob(1);
337 	if (fs->fs_magic == FS_UFS2_MAGIC) {
338 		if (!isaltsblk) {
339 			CHK(fs->fs_sblockloc, !=, SBLOCK_UFS2, %#jx);
340 			CHK2(fs->fs_sblockactualloc, !=, SBLOCK_UFS2,
341 			    fs->fs_sblockactualloc, !=, 0, %jd);
342 		}
343 		CHK(fs->fs_maxsymlinklen, !=, ((UFS_NDADDR + UFS_NIADDR) *
344 			sizeof(ufs2_daddr_t)), %jd);
345 		CHK(fs->fs_nindir, !=, fs->fs_bsize / sizeof(ufs2_daddr_t),
346 		    %jd);
347 		CHK(fs->fs_inopb, !=, fs->fs_bsize / sizeof(struct ufs2_dinode),
348 		    %jd);
349 	} else if (fs->fs_magic == FS_UFS1_MAGIC) {
350 		if (!isaltsblk) {
351 			CHK(fs->fs_sblockloc, >, SBLOCK_UFS1, %jd);
352 			/*
353 			 * For UFS1 the with a 65536 block size, the first
354 			 * backup superblock is at the same location as the
355 			 * UFS2 superblock. Since SBLOCK_UFS2 is the first
356 			 * location checked, the first backup is the
357 			 * superblock that will be accessed.
358 			 */
359 			if (fs->fs_bsize == SBLOCK_UFS2) {
360 				CHK(fs->fs_sblockactualloc, >, SBLOCK_UFS2,
361 				    %jd);
362 			} else {
363 				CHK2(fs->fs_sblockactualloc, !=, SBLOCK_UFS1,
364 				    fs->fs_sblockactualloc, !=, 0, %jd);
365 			}
366 		}
367 		CHK(fs->fs_nindir, !=, fs->fs_bsize / sizeof(ufs1_daddr_t),
368 		    %jd);
369 		CHK(fs->fs_inopb, !=, fs->fs_bsize / sizeof(struct ufs1_dinode),
370 		    %jd);
371 		CHK(fs->fs_maxsymlinklen, !=, ((UFS_NDADDR + UFS_NIADDR) *
372 			sizeof(ufs1_daddr_t)), %jd);
373 		CHK(fs->fs_old_inodefmt, !=, FS_44INODEFMT, %jd);
374 		CHK(fs->fs_old_cgoffset, !=, 0, %jd);
375 		CHK(fs->fs_old_cgmask, !=, 0xffffffff, %#jx);
376 		CHK(fs->fs_old_rotdelay, !=, 0, %jd);
377 		CHK(fs->fs_old_rps, !=, 60, %jd);
378 		CHK(fs->fs_old_nspf, !=, fs->fs_fsize / sectorsize, %jd);
379 		CHK(fs->fs_old_cpg, !=, 1, %jd);
380 		CHK(fs->fs_old_interleave, !=, 1, %jd);
381 		CHK(fs->fs_old_trackskew, !=, 0, %jd);
382 		CHK(fs->fs_old_cpc, !=, 0, %jd);
383 		CHK(fs->fs_old_postblformat, !=, 1, %jd);
384 		CHK(fs->fs_old_nrpos, !=, 1, %jd);
385 		CHK(fs->fs_old_spc, !=, fs->fs_fpg * fs->fs_old_nspf, %jd);
386 		CHK(fs->fs_old_nsect, !=, fs->fs_old_spc, %jd);
387 		CHK(fs->fs_old_npsect, !=, fs->fs_old_spc, %jd);
388 		CHK(fs->fs_old_ncyl, !=, fs->fs_ncg, %jd);
389 	} else {
390 		/* Bad magic number, so assume not a superblock */
391 		return (ENOENT);
392 	}
393 	CHK(fs->fs_bsize, <, MINBSIZE, %jd);
394 	CHK(fs->fs_bsize, >, MAXBSIZE, %jd);
395 	CHK(fs->fs_bsize, <, roundup(sizeof(struct fs), DEV_BSIZE), %jd);
396 	CHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
397 	CHK(powerof2(fs->fs_bsize), ==, 0, %jd);
398 	CHK(fs->fs_fsize, <, sectorsize, %jd);
399 	CHK(fs->fs_fsize, >, fs->fs_bsize, %jd);
400 	CHK(fs->fs_fsize * MAXFRAG, <, fs->fs_bsize, %jd);
401 	CHK(powerof2(fs->fs_fsize), ==, 0, %jd);
402 	CHK(fs->fs_maxbsize, <, fs->fs_bsize, %jd);
403 	CHK(powerof2(fs->fs_maxbsize), ==, 0, %jd);
404 	CHK(fs->fs_maxbsize, >, FS_MAXCONTIG * fs->fs_bsize, %jd);
405 	CHK(fs->fs_bmask, !=, ~(fs->fs_bsize - 1), %#jx);
406 	CHK(fs->fs_fmask, !=, ~(fs->fs_fsize - 1), %#jx);
407 	CHK(fs->fs_qbmask, !=, ~fs->fs_bmask, %#jx);
408 	CHK(fs->fs_qfmask, !=, ~fs->fs_fmask, %#jx);
409 	CHK(fs->fs_bshift, !=, ILOG2(fs->fs_bsize), %jd);
410 	CHK(fs->fs_fshift, !=, ILOG2(fs->fs_fsize), %jd);
411 	CHK(fs->fs_frag, !=, numfrags(fs, fs->fs_bsize), %jd);
412 	CHK(fs->fs_fragshift, !=, ILOG2(fs->fs_frag), %jd);
413 	CHK(fs->fs_frag, >, MAXFRAG, %jd);
414 	CHK(fs->fs_fsbtodb, !=, ILOG2(fs->fs_fsize / sectorsize), %jd);
415 	CHK(fs->fs_sblkno, !=, roundup(
416 	    howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize),
417 	    fs->fs_frag), %jd);
418 	CHK(fs->fs_cblkno, !=, fs->fs_sblkno +
419 	    roundup(howmany(SBLOCKSIZE, fs->fs_fsize), fs->fs_frag), %jd);
420 	CHK(fs->fs_iblkno, !=, fs->fs_cblkno + fs->fs_frag, %jd);
421 	CHK(fs->fs_dblkno, !=, fs->fs_iblkno + fs->fs_ipg / INOPF(fs), %jd);
422 	CHK(fs->fs_cgsize, >, fs->fs_bsize, %jd);
423 	CHK(fs->fs_cssize, !=,
424 		fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
425 	/*
426 	 * This test is valid, however older versions of growfs failed
427 	 * to correctly update fs_dsize so will fail this test. Thus we
428 	 * exclude it from the requirements.
429 	 */
430 #ifdef notdef
431 	CHK(fs->fs_dsize, !=, fs->fs_size - fs->fs_sblkno -
432 		fs->fs_ncg * (fs->fs_dblkno - fs->fs_sblkno) -
433 		howmany(fs->fs_cssize, fs->fs_fsize), %jd);
434 #endif
435 	CHK(fs->fs_metaspace, <, 0, %jd);
436 	CHK(fs->fs_metaspace, >, fs->fs_fpg / 2, %jd);
437 	CHK(fs->fs_minfree, >, 99, %jd%%);
438 	maxfilesize = fs->fs_bsize * UFS_NDADDR - 1;
439 	for (sizepb = fs->fs_bsize, i = 0; i < UFS_NIADDR; i++) {
440 		sizepb *= NINDIR(fs);
441 		maxfilesize += sizepb;
442 	}
443 	CHK(fs->fs_maxfilesize, !=, maxfilesize, %jd);
444 	/*
445 	 * These values have a tight interaction with each other that
446 	 * makes it hard to tightly bound them. So we can only check
447 	 * that they are within a broader possible range.
448 	 *
449 	 * The size cannot always be accurately determined, but ensure
450 	 * that it is consistent with the number of cylinder groups (fs_ncg)
451 	 * and the number of fragments per cylinder group (fs_fpg). Ensure
452 	 * that the summary information size is correct and that it starts
453 	 * and ends in the data area of the same cylinder group.
454 	 */
455 	CHK(fs->fs_ncg, <, 1, %jd);
456 	CHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
457 	CHK(fs->fs_size, <=, (fs->fs_ncg - 1) * fs->fs_fpg, %jd);
458 	CHK(fs->fs_size, >, fs->fs_ncg * fs->fs_fpg, %jd);
459 	CHK(fs->fs_cssize, !=,
460 	    fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
461 	CHK(dtog(fs, fs->fs_csaddr), >, fs->fs_ncg, %jd);
462 	cgnum = dtog(fs, fs->fs_csaddr);
463 	CHK(fs->fs_csaddr, <, cgdmin(fs, cgnum), %jd);
464 	CHK(dtog(fs, fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize)), >,
465 	    cgnum, %jd);
466 	CHK(fs->fs_ipg * fs->fs_ncg, >, (((int64_t)(1)) << 32) - INOPB(fs),
467 	    %jd);
468 	/*
469 	 * With file system clustering it is possible to allocate
470 	 * many contiguous blocks. The kernel variable maxphys defines
471 	 * the maximum transfer size permitted by the controller and/or
472 	 * buffering. The fs_maxcontig parameter controls the maximum
473 	 * number of blocks that the filesystem will read or write
474 	 * in a single transfer. It is calculated when the filesystem
475 	 * is created as maxphys / fs_bsize. The loader uses a maxphys
476 	 * of 128K even when running on a system that supports larger
477 	 * values. If the filesystem was built on a system that supports
478 	 * a larger maxphys (1M is typical) it will have configured
479 	 * fs_maxcontig for that larger system. So we bound the upper
480 	 * allowable limit for fs_maxconfig to be able to at least
481 	 * work with a 1M maxphys on the smallest block size filesystem:
482 	 * 1M / 4096 == 256. There is no harm in allowing the mounting of
483 	 * filesystems that make larger than maxphys I/O requests because
484 	 * those (mostly 32-bit machines) can (very slowly) handle I/O
485 	 * requests that exceed maxphys.
486 	 */
487 	CHK(fs->fs_maxcontig, <, 0, %jd);
488 	CHK(fs->fs_maxcontig, >, MAX(256, maxphys / fs->fs_bsize), %jd);
489 	CHK2(fs->fs_maxcontig, ==, 0, fs->fs_contigsumsize, !=, 0, %jd);
490 	CHK2(fs->fs_maxcontig, >, 1, fs->fs_contigsumsize, !=,
491 	    MIN(fs->fs_maxcontig, FS_MAXCONTIG), %jd);
492 	return (0);
493 }
494 
495 /*
496  * Write a superblock to the devfd device from the memory pointed to by fs.
497  * Write out the superblock summary information if it is present.
498  *
499  * If the write is successful, zero is returned. Otherwise one of the
500  * following error values is returned:
501  *     EIO: failed to write superblock.
502  *     EIO: failed to write superblock summary information.
503  */
504 int
505 ffs_sbput(void *devfd, struct fs *fs, off_t loc,
506     int (*writefunc)(void *devfd, off_t loc, void *buf, int size))
507 {
508 	int i, error, blks, size;
509 	uint8_t *space;
510 
511 	/*
512 	 * If there is summary information, write it first, so if there
513 	 * is an error, the superblock will not be marked as clean.
514 	 */
515 	if (fs->fs_si != NULL && fs->fs_csp != NULL) {
516 		blks = howmany(fs->fs_cssize, fs->fs_fsize);
517 		space = (uint8_t *)fs->fs_csp;
518 		for (i = 0; i < blks; i += fs->fs_frag) {
519 			size = fs->fs_bsize;
520 			if (i + fs->fs_frag > blks)
521 				size = (blks - i) * fs->fs_fsize;
522 			if ((error = (*writefunc)(devfd,
523 			     dbtob(fsbtodb(fs, fs->fs_csaddr + i)),
524 			     space, size)) != 0)
525 				return (error);
526 			space += size;
527 		}
528 	}
529 	fs->fs_fmod = 0;
530 #ifndef _KERNEL
531 	{
532 		struct fs_summary_info *fs_si;
533 
534 		fs->fs_time = time(NULL);
535 		/* Clear the pointers for the duration of writing. */
536 		fs_si = fs->fs_si;
537 		fs->fs_si = NULL;
538 		fs->fs_ckhash = ffs_calc_sbhash(fs);
539 		error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize);
540 		fs->fs_si = fs_si;
541 	}
542 #else /* _KERNEL */
543 	fs->fs_time = time_second;
544 	fs->fs_ckhash = ffs_calc_sbhash(fs);
545 	error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize);
546 #endif /* _KERNEL */
547 	return (error);
548 }
549 
550 /*
551  * Calculate the check-hash for a superblock.
552  */
553 uint32_t
554 ffs_calc_sbhash(struct fs *fs)
555 {
556 	uint32_t ckhash, save_ckhash;
557 
558 	/*
559 	 * A filesystem that was using a superblock ckhash may be moved
560 	 * to an older kernel that does not support ckhashes. The
561 	 * older kernel will clear the FS_METACKHASH flag indicating
562 	 * that it does not update hashes. When the disk is moved back
563 	 * to a kernel capable of ckhashes it disables them on mount:
564 	 *
565 	 *	if ((fs->fs_flags & FS_METACKHASH) == 0)
566 	 *		fs->fs_metackhash = 0;
567 	 *
568 	 * This leaves (fs->fs_metackhash & CK_SUPERBLOCK) == 0) with an
569 	 * old stale value in the fs->fs_ckhash field. Thus the need to
570 	 * just accept what is there.
571 	 */
572 	if ((fs->fs_metackhash & CK_SUPERBLOCK) == 0)
573 		return (fs->fs_ckhash);
574 
575 	save_ckhash = fs->fs_ckhash;
576 	fs->fs_ckhash = 0;
577 	/*
578 	 * If newly read from disk, the caller is responsible for
579 	 * verifying that fs->fs_sbsize <= SBLOCKSIZE.
580 	 */
581 	ckhash = calculate_crc32c(~0L, (void *)fs, fs->fs_sbsize);
582 	fs->fs_ckhash = save_ckhash;
583 	return (ckhash);
584 }
585 
586 /*
587  * Update the frsum fields to reflect addition or deletion
588  * of some frags.
589  */
590 void
591 ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt)
592 {
593 	int inblk;
594 	int field, subfield;
595 	int siz, pos;
596 
597 	inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
598 	fragmap <<= 1;
599 	for (siz = 1; siz < fs->fs_frag; siz++) {
600 		if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0)
601 			continue;
602 		field = around[siz];
603 		subfield = inside[siz];
604 		for (pos = siz; pos <= fs->fs_frag; pos++) {
605 			if ((fragmap & field) == subfield) {
606 				fraglist[siz] += cnt;
607 				pos += siz;
608 				field <<= siz;
609 				subfield <<= siz;
610 			}
611 			field <<= 1;
612 			subfield <<= 1;
613 		}
614 	}
615 }
616 
617 /*
618  * block operations
619  *
620  * check if a block is available
621  */
622 int
623 ffs_isblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h)
624 {
625 	unsigned char mask;
626 
627 	switch ((int)fs->fs_frag) {
628 	case 8:
629 		return (cp[h] == 0xff);
630 	case 4:
631 		mask = 0x0f << ((h & 0x1) << 2);
632 		return ((cp[h >> 1] & mask) == mask);
633 	case 2:
634 		mask = 0x03 << ((h & 0x3) << 1);
635 		return ((cp[h >> 2] & mask) == mask);
636 	case 1:
637 		mask = 0x01 << (h & 0x7);
638 		return ((cp[h >> 3] & mask) == mask);
639 	default:
640 #ifdef _KERNEL
641 		panic("ffs_isblock");
642 #endif
643 		break;
644 	}
645 	return (0);
646 }
647 
648 /*
649  * check if a block is free
650  */
651 int
652 ffs_isfreeblock(struct fs *fs, u_char *cp, ufs1_daddr_t h)
653 {
654 
655 	switch ((int)fs->fs_frag) {
656 	case 8:
657 		return (cp[h] == 0);
658 	case 4:
659 		return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0);
660 	case 2:
661 		return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0);
662 	case 1:
663 		return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0);
664 	default:
665 #ifdef _KERNEL
666 		panic("ffs_isfreeblock");
667 #endif
668 		break;
669 	}
670 	return (0);
671 }
672 
673 /*
674  * take a block out of the map
675  */
676 void
677 ffs_clrblock(struct fs *fs, u_char *cp, ufs1_daddr_t h)
678 {
679 
680 	switch ((int)fs->fs_frag) {
681 	case 8:
682 		cp[h] = 0;
683 		return;
684 	case 4:
685 		cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
686 		return;
687 	case 2:
688 		cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
689 		return;
690 	case 1:
691 		cp[h >> 3] &= ~(0x01 << (h & 0x7));
692 		return;
693 	default:
694 #ifdef _KERNEL
695 		panic("ffs_clrblock");
696 #endif
697 		break;
698 	}
699 }
700 
701 /*
702  * put a block into the map
703  */
704 void
705 ffs_setblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h)
706 {
707 
708 	switch ((int)fs->fs_frag) {
709 	case 8:
710 		cp[h] = 0xff;
711 		return;
712 	case 4:
713 		cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
714 		return;
715 	case 2:
716 		cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
717 		return;
718 	case 1:
719 		cp[h >> 3] |= (0x01 << (h & 0x7));
720 		return;
721 	default:
722 #ifdef _KERNEL
723 		panic("ffs_setblock");
724 #endif
725 		break;
726 	}
727 }
728 
729 /*
730  * Update the cluster map because of an allocation or free.
731  *
732  * Cnt == 1 means free; cnt == -1 means allocating.
733  */
734 void
735 ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_daddr_t blkno, int cnt)
736 {
737 	int32_t *sump;
738 	int32_t *lp;
739 	u_char *freemapp, *mapp;
740 	int i, start, end, forw, back, map;
741 	u_int bit;
742 
743 	if (fs->fs_contigsumsize <= 0)
744 		return;
745 	freemapp = cg_clustersfree(cgp);
746 	sump = cg_clustersum(cgp);
747 	/*
748 	 * Allocate or clear the actual block.
749 	 */
750 	if (cnt > 0)
751 		setbit(freemapp, blkno);
752 	else
753 		clrbit(freemapp, blkno);
754 	/*
755 	 * Find the size of the cluster going forward.
756 	 */
757 	start = blkno + 1;
758 	end = start + fs->fs_contigsumsize;
759 	if (end >= cgp->cg_nclusterblks)
760 		end = cgp->cg_nclusterblks;
761 	mapp = &freemapp[start / NBBY];
762 	map = *mapp++;
763 	bit = 1U << (start % NBBY);
764 	for (i = start; i < end; i++) {
765 		if ((map & bit) == 0)
766 			break;
767 		if ((i & (NBBY - 1)) != (NBBY - 1)) {
768 			bit <<= 1;
769 		} else {
770 			map = *mapp++;
771 			bit = 1;
772 		}
773 	}
774 	forw = i - start;
775 	/*
776 	 * Find the size of the cluster going backward.
777 	 */
778 	start = blkno - 1;
779 	end = start - fs->fs_contigsumsize;
780 	if (end < 0)
781 		end = -1;
782 	mapp = &freemapp[start / NBBY];
783 	map = *mapp--;
784 	bit = 1U << (start % NBBY);
785 	for (i = start; i > end; i--) {
786 		if ((map & bit) == 0)
787 			break;
788 		if ((i & (NBBY - 1)) != 0) {
789 			bit >>= 1;
790 		} else {
791 			map = *mapp--;
792 			bit = 1U << (NBBY - 1);
793 		}
794 	}
795 	back = start - i;
796 	/*
797 	 * Account for old cluster and the possibly new forward and
798 	 * back clusters.
799 	 */
800 	i = back + forw + 1;
801 	if (i > fs->fs_contigsumsize)
802 		i = fs->fs_contigsumsize;
803 	sump[i] += cnt;
804 	if (back > 0)
805 		sump[back] -= cnt;
806 	if (forw > 0)
807 		sump[forw] -= cnt;
808 	/*
809 	 * Update cluster summary information.
810 	 */
811 	lp = &sump[fs->fs_contigsumsize];
812 	for (i = fs->fs_contigsumsize; i > 0; i--)
813 		if (*lp-- > 0)
814 			break;
815 	fs->fs_maxcluster[cgp->cg_cgx] = i;
816 }
817