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
ffs_verify_dinode_ckhash(struct fs * fs,struct ufs2_dinode * dip)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
ffs_update_dinode_ckhash(struct fs * fs,struct ufs2_dinode * dip)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
ffs_sbget(void * devfd,struct fs ** fsp,off_t sblock,int flags,struct malloc_type * filltype,int (* readfunc)(void * devfd,off_t loc,void ** bufp,int size))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
readsuper(void * devfd,struct fs ** fsp,off_t sblockloc,int flags,int (* readfunc)(void * devfd,off_t loc,void ** bufp,int size))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
validate_sblock(struct fs * fs,int flags)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
ffs_sbsearch(void * devfd,struct fs ** fsp,int reqflags,struct malloc_type * filltype,int (* readfunc)(void * devfd,off_t loc,void ** bufp,int size))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
ffs_sbput(void * devfd,struct fs * fs,off_t loc,int (* writefunc)(void * devfd,off_t loc,void * buf,int size))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
ffs_calc_sbhash(struct fs * fs)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
ffs_fragacct(struct fs * fs,int fragmap,int32_t fraglist[],int cnt)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
ffs_isblock(struct fs * fs,unsigned char * cp,ufs1_daddr_t h)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
ffs_isfreeblock(struct fs * fs,uint8_t * cp,ufs1_daddr_t h)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
ffs_clrblock(struct fs * fs,uint8_t * cp,ufs1_daddr_t h)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
ffs_setblock(struct fs * fs,unsigned char * cp,ufs1_daddr_t h)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
ffs_clusteracct(struct fs * fs,struct cg * cgp,ufs1_daddr_t blkno,int cnt)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