/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)ffs_subr.c 8.5 (Berkeley) 3/21/95 */ #include __FBSDID("$FreeBSD$"); #include #include #ifndef _KERNEL #include #include #include #include #include #include #include uint32_t calculate_crc32c(uint32_t, const void *, size_t); uint32_t ffs_calc_sbhash(struct fs *); struct malloc_type; #define UFS_MALLOC(size, type, flags) malloc(size) #define UFS_FREE(ptr, type) free(ptr) #define maxphys MAXPHYS #else /* _KERNEL */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define UFS_MALLOC(size, type, flags) malloc(size, type, flags) #define UFS_FREE(ptr, type) free(ptr, type) #endif /* _KERNEL */ /* * Verify an inode check-hash. */ int ffs_verify_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip) { uint32_t ckhash, save_ckhash; /* * Return success if unallocated or we are not doing inode check-hash. */ if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0) return (0); /* * Exclude di_ckhash from the crc32 calculation, e.g., always use * a check-hash value of zero when calculating the check-hash. */ save_ckhash = dip->di_ckhash; dip->di_ckhash = 0; ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip)); dip->di_ckhash = save_ckhash; if (save_ckhash == ckhash) return (0); return (EINVAL); } /* * Update an inode check-hash. */ void ffs_update_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip) { if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0) return; /* * Exclude old di_ckhash from the crc32 calculation, e.g., always use * a check-hash value of zero when calculating the new check-hash. */ dip->di_ckhash = 0; dip->di_ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip)); } /* * These are the low-level functions that actually read and write * the superblock and its associated data. */ static off_t sblock_try[] = SBLOCKSEARCH; static int readsuper(void *, struct fs **, off_t, int, int, int (*)(void *, off_t, void **, int)); static int validate_sblock(struct fs *, int); /* * Read a superblock from the devfd device. * * If an alternate superblock is specified, it is read. Otherwise the * set of locations given in the SBLOCKSEARCH list is searched for a * superblock. Memory is allocated for the superblock by the readfunc and * is returned. If filltype is non-NULL, additional memory is allocated * of type filltype and filled in with the superblock summary information. * All memory is freed when any error is returned. * * If a superblock is found, zero is returned. Otherwise one of the * following error values is returned: * EIO: non-existent or truncated superblock. * EIO: error reading summary information. * ENOENT: no usable known superblock found. * ENOMEM: failed to allocate space for the superblock. * EINVAL: The previous newfs operation on this volume did not complete. * The administrator must complete newfs before using this volume. */ int ffs_sbget(void *devfd, struct fs **fsp, off_t altsblock, struct malloc_type *filltype, int (*readfunc)(void *devfd, off_t loc, void **bufp, int size)) { struct fs *fs; struct fs_summary_info *fs_si; int i, error; uint64_t size, blks; uint8_t *space; int32_t *lp; char *buf; fs = NULL; *fsp = NULL; if (altsblock >= 0) { if ((error = readsuper(devfd, &fs, altsblock, 1, 0, readfunc)) != 0) { if (fs != NULL) UFS_FREE(fs, filltype); return (error); } } else { for (i = 0; sblock_try[i] != -1; i++) { if ((error = readsuper(devfd, &fs, sblock_try[i], 0, altsblock, readfunc)) == 0) break; if (fs != NULL) { UFS_FREE(fs, filltype); fs = NULL; } if (error == ENOENT) continue; return (error); } if (sblock_try[i] == -1) return (ENOENT); } /* * Read in the superblock summary information. */ size = fs->fs_cssize; blks = howmany(size, fs->fs_fsize); if (fs->fs_contigsumsize > 0) size += fs->fs_ncg * sizeof(int32_t); size += fs->fs_ncg * sizeof(u_int8_t); if ((fs_si = UFS_MALLOC(sizeof(*fs_si), filltype, M_NOWAIT)) == NULL) { UFS_FREE(fs, filltype); return (ENOMEM); } bzero(fs_si, sizeof(*fs_si)); fs->fs_si = fs_si; if ((space = UFS_MALLOC(size, filltype, M_NOWAIT)) == NULL) { UFS_FREE(fs->fs_si, filltype); UFS_FREE(fs, filltype); return (ENOMEM); } fs->fs_csp = (struct csum *)space; for (i = 0; i < blks; i += fs->fs_frag) { size = fs->fs_bsize; if (i + fs->fs_frag > blks) size = (blks - i) * fs->fs_fsize; buf = NULL; error = (*readfunc)(devfd, dbtob(fsbtodb(fs, fs->fs_csaddr + i)), (void **)&buf, size); if (error) { if (buf != NULL) UFS_FREE(buf, filltype); UFS_FREE(fs->fs_csp, filltype); UFS_FREE(fs->fs_si, filltype); UFS_FREE(fs, filltype); return (error); } memcpy(space, buf, size); UFS_FREE(buf, filltype); space += size; } if (fs->fs_contigsumsize > 0) { fs->fs_maxcluster = lp = (int32_t *)space; for (i = 0; i < fs->fs_ncg; i++) *lp++ = fs->fs_contigsumsize; space = (uint8_t *)lp; } size = fs->fs_ncg * sizeof(u_int8_t); fs->fs_contigdirs = (u_int8_t *)space; bzero(fs->fs_contigdirs, size); *fsp = fs; return (0); } /* * Try to read a superblock from the location specified by sblockloc. * Return zero on success or an errno on failure. */ static int readsuper(void *devfd, struct fs **fsp, off_t sblockloc, int isaltsblk, int chkhash, int (*readfunc)(void *devfd, off_t loc, void **bufp, int size)) { struct fs *fs; int error, res; uint32_t ckhash; error = (*readfunc)(devfd, sblockloc, (void **)fsp, SBLOCKSIZE); if (error != 0) return (error); fs = *fsp; if (fs->fs_magic == FS_BAD_MAGIC) return (EINVAL); if ((error = validate_sblock(fs, isaltsblk)) != 0) return (error); /* * If the filesystem has been run on a kernel without * metadata check hashes, disable them. */ if ((fs->fs_flags & FS_METACKHASH) == 0) fs->fs_metackhash = 0; /* * Clear any check-hashes that are not maintained * by this kernel. Also clear any unsupported flags. */ fs->fs_metackhash &= CK_SUPPORTED; fs->fs_flags &= FS_SUPPORTED; if (fs->fs_ckhash != (ckhash = ffs_calc_sbhash(fs))) { if (chkhash == STDSB_NOMSG) return (EINTEGRITY); if (chkhash == STDSB_NOHASHFAIL_NOMSG) return (0); #ifdef _KERNEL res = uprintf("Superblock check-hash failed: recorded " "check-hash 0x%x != computed check-hash 0x%x%s\n", fs->fs_ckhash, ckhash, chkhash == STDSB_NOHASHFAIL ? " (Ignored)" : ""); #else res = 0; #endif /* * Print check-hash failure if no controlling terminal * in kernel or always if in user-mode (libufs). */ if (res == 0) printf("Superblock check-hash failed: recorded " "check-hash 0x%x != computed check-hash " "0x%x%s\n", fs->fs_ckhash, ckhash, chkhash == STDSB_NOHASHFAIL ? " (Ignored)" : ""); if (chkhash == STDSB) return (EINTEGRITY); /* chkhash == STDSB_NOHASHFAIL */ return (0); } /* Have to set for old filesystems that predate this field */ fs->fs_sblockactualloc = sblockloc; /* Not yet any summary information */ fs->fs_si = NULL; return (0); } /* * Verify the filesystem values. */ #define ILOG2(num) (fls(num) - 1) static int validate_sblock(struct fs *fs, int isaltsblk) { int i, sectorsize; u_int64_t maxfilesize, minfpg, sizepb; sectorsize = dbtob(1); if (fs->fs_magic == FS_UFS2_MAGIC) { if ((!isaltsblk && (fs->fs_sblockloc != SBLOCK_UFS2 || !(fs->fs_sblockactualloc == 0 || fs->fs_sblockactualloc == SBLOCK_UFS2))) || fs->fs_maxsymlinklen != ((UFS_NDADDR + UFS_NIADDR) * sizeof(ufs2_daddr_t)) || fs->fs_nindir != fs->fs_bsize / sizeof(ufs2_daddr_t) || fs->fs_inopb != fs->fs_bsize / sizeof(struct ufs2_dinode)) return (ENOENT); } else if (fs->fs_magic == FS_UFS1_MAGIC) { if ((!isaltsblk && (fs->fs_sblockloc > SBLOCK_UFS1 || !(fs->fs_sblockactualloc == SBLOCK_UFS1 || fs->fs_sblockactualloc == 0))) || fs->fs_nindir != fs->fs_bsize / sizeof(ufs1_daddr_t) || fs->fs_inopb != fs->fs_bsize / sizeof(struct ufs1_dinode) || fs->fs_maxsymlinklen != ((UFS_NDADDR + UFS_NIADDR) * sizeof(ufs1_daddr_t)) || fs->fs_old_inodefmt != FS_44INODEFMT || fs->fs_old_cgoffset != 0 || fs->fs_old_cgmask != 0xffffffff || fs->fs_old_size != fs->fs_size || fs->fs_old_rotdelay != 0 || fs->fs_old_rps != 60 || fs->fs_old_nspf != fs->fs_fsize / sectorsize || fs->fs_old_cpg != 1 || fs->fs_old_interleave != 1 || fs->fs_old_trackskew != 0 || fs->fs_old_cpc != 0 || fs->fs_old_postblformat != 1 || fs->fs_old_nrpos != 1 || fs->fs_old_spc != fs->fs_fpg * fs->fs_old_nspf || fs->fs_old_nsect != fs->fs_old_spc || fs->fs_old_npsect != fs->fs_old_spc || fs->fs_old_dsize != fs->fs_dsize || fs->fs_old_ncyl != fs->fs_ncg) return (ENOENT); } else { return (ENOENT); } if (fs->fs_bsize < MINBSIZE || fs->fs_bsize > MAXBSIZE || fs->fs_bsize < roundup(sizeof(struct fs), DEV_BSIZE) || fs->fs_sbsize > SBLOCKSIZE || fs->fs_sbsize < fs->fs_fsize || !powerof2(fs->fs_bsize)) return (ENOENT); if (fs->fs_fsize < sectorsize || fs->fs_fsize > fs->fs_bsize || fs->fs_fsize * MAXFRAG < fs->fs_bsize || !powerof2(fs->fs_fsize)) return (ENOENT); if (fs->fs_maxbsize < fs->fs_bsize || !powerof2(fs->fs_maxbsize) || fs->fs_maxbsize > FS_MAXCONTIG * fs->fs_bsize) return (ENOENT); if (fs->fs_bmask != ~(fs->fs_bsize - 1) || fs->fs_fmask != ~(fs->fs_fsize - 1) || fs->fs_qbmask != ~fs->fs_bmask || fs->fs_qfmask != ~fs->fs_fmask || fs->fs_bshift != ILOG2(fs->fs_bsize) || fs->fs_fshift != ILOG2(fs->fs_fsize) || fs->fs_frag != numfrags(fs, fs->fs_bsize) || fs->fs_fragshift != ILOG2(fs->fs_frag) || fs->fs_frag > MAXFRAG || fs->fs_fsbtodb != ILOG2(fs->fs_fsize / sectorsize)) return (ENOENT); if (fs->fs_sblkno != roundup(howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize), fs->fs_frag) || fs->fs_cblkno != fs->fs_sblkno + roundup(howmany(SBLOCKSIZE, fs->fs_fsize), fs->fs_frag) || fs->fs_iblkno != fs->fs_cblkno + fs->fs_frag || fs->fs_dblkno != fs->fs_iblkno + fs->fs_ipg / INOPF(fs) || fs->fs_cgsize > fs->fs_bsize) return (ENOENT); if (fs->fs_csaddr != cgdmin(fs, 0) || fs->fs_cssize != fragroundup(fs, fs->fs_ncg * sizeof(struct csum)) || fs->fs_dsize != fs->fs_size - fs->fs_sblkno - fs->fs_ncg * (fs->fs_dblkno - fs->fs_sblkno) - howmany(fs->fs_cssize, fs->fs_fsize) || fs->fs_metaspace < 0 || fs->fs_metaspace > fs->fs_fpg / 2 || fs->fs_minfree > 99) return (ENOENT); maxfilesize = fs->fs_bsize * UFS_NDADDR - 1; for (sizepb = fs->fs_bsize, i = 0; i < UFS_NIADDR; i++) { sizepb *= NINDIR(fs); maxfilesize += sizepb; } if (fs->fs_maxfilesize != maxfilesize) return (ENOENT); /* * These values have a tight interaction with each other that * makes it hard to tightly bound them. So we can only check * that they are within a broader possible range. * * Calculate minfpg, the minimum number of fragments that can be * in a cylinder group. The value 12289 is calculated in newfs(8) * when creating the smallest block size UFS version 1 filesystem * (4096 block size) with no fragments (4096 fragment size). That * number may be depressed even further for very small filesystems * since newfs(8) strives to have at least four cylinder groups. */ minfpg = MIN(12289, fs->fs_size / 4); if (fs->fs_ncg < 1 || fs->fs_ncg > (fs->fs_size / minfpg) + 1 || fs->fs_fpg < minfpg || fs->fs_fpg > fs->fs_size || fs->fs_ipg * fs->fs_ncg > (((int64_t)(1)) << 32) - INOPB(fs) || fs->fs_ipg > fs->fs_fpg || fs->fs_size < 8 * fs->fs_frag) return (ENOENT); if (fs->fs_size <= (fs->fs_ncg - 1) * fs->fs_fpg || fs->fs_size > fs->fs_ncg * fs->fs_fpg) return (ENOENT); /* * With file system clustering it is possible to allocate * many contiguous blocks. The kernel variable maxphys defines * the maximum transfer size permitted by the controller and/or * buffering. The fs_maxcontig parameter controls the maximum * number of blocks that the filesystem will read or write * in a single transfer. It is calculated when the filesystem * is created as maxphys / fs_bsize. The loader uses a maxphys * of 128K even when running on a system that supports larger * values. If the filesystem was built on a system that supports * a larger maxphys (1M is typical) it will have configured * fs_maxcontig for that larger system. So we bound the upper * allowable limit for fs_maxconfig to be able to at least * work with a 1M maxphys on the smallest block size filesystem: * 1M / 4096 == 256. There is no harm in allowing the mounting of * filesystems that make larger than maxphys I/O requests because * those (mostly 32-bit machines) can (very slowly) handle I/O * requests that exceed maxphys. */ if (fs->fs_maxcontig < 1 || fs->fs_maxcontig > MAX(256, maxphys / fs->fs_bsize)) return (ENOENT); if (fs->fs_maxcontig < 0 || (fs->fs_maxcontig == 0 && fs->fs_contigsumsize != 0) || (fs->fs_maxcontig > 1 && fs->fs_contigsumsize != MIN(fs->fs_maxcontig, FS_MAXCONTIG))) return (ENOENT); return (0); } /* * Write a superblock to the devfd device from the memory pointed to by fs. * Write out the superblock summary information if it is present. * * If the write is successful, zero is returned. Otherwise one of the * following error values is returned: * EIO: failed to write superblock. * EIO: failed to write superblock summary information. */ int ffs_sbput(void *devfd, struct fs *fs, off_t loc, int (*writefunc)(void *devfd, off_t loc, void *buf, int size)) { int i, error, blks, size; uint8_t *space; /* * If there is summary information, write it first, so if there * is an error, the superblock will not be marked as clean. */ if (fs->fs_si != NULL && fs->fs_csp != NULL) { blks = howmany(fs->fs_cssize, fs->fs_fsize); space = (uint8_t *)fs->fs_csp; for (i = 0; i < blks; i += fs->fs_frag) { size = fs->fs_bsize; if (i + fs->fs_frag > blks) size = (blks - i) * fs->fs_fsize; if ((error = (*writefunc)(devfd, dbtob(fsbtodb(fs, fs->fs_csaddr + i)), space, size)) != 0) return (error); space += size; } } fs->fs_fmod = 0; #ifndef _KERNEL { struct fs_summary_info *fs_si; fs->fs_time = time(NULL); /* Clear the pointers for the duration of writing. */ fs_si = fs->fs_si; fs->fs_si = NULL; fs->fs_ckhash = ffs_calc_sbhash(fs); error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize); fs->fs_si = fs_si; } #else /* _KERNEL */ fs->fs_time = time_second; fs->fs_ckhash = ffs_calc_sbhash(fs); error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize); #endif /* _KERNEL */ return (error); } /* * Calculate the check-hash for a superblock. */ uint32_t ffs_calc_sbhash(struct fs *fs) { uint32_t ckhash, save_ckhash; /* * A filesystem that was using a superblock ckhash may be moved * to an older kernel that does not support ckhashes. The * older kernel will clear the FS_METACKHASH flag indicating * that it does not update hashes. When the disk is moved back * to a kernel capable of ckhashes it disables them on mount: * * if ((fs->fs_flags & FS_METACKHASH) == 0) * fs->fs_metackhash = 0; * * This leaves (fs->fs_metackhash & CK_SUPERBLOCK) == 0) with an * old stale value in the fs->fs_ckhash field. Thus the need to * just accept what is there. */ if ((fs->fs_metackhash & CK_SUPERBLOCK) == 0) return (fs->fs_ckhash); save_ckhash = fs->fs_ckhash; fs->fs_ckhash = 0; /* * If newly read from disk, the caller is responsible for * verifying that fs->fs_sbsize <= SBLOCKSIZE. */ ckhash = calculate_crc32c(~0L, (void *)fs, fs->fs_sbsize); fs->fs_ckhash = save_ckhash; return (ckhash); } /* * Update the frsum fields to reflect addition or deletion * of some frags. */ void ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt) { int inblk; int field, subfield; int siz, pos; inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1; fragmap <<= 1; for (siz = 1; siz < fs->fs_frag; siz++) { if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0) continue; field = around[siz]; subfield = inside[siz]; for (pos = siz; pos <= fs->fs_frag; pos++) { if ((fragmap & field) == subfield) { fraglist[siz] += cnt; pos += siz; field <<= siz; subfield <<= siz; } field <<= 1; subfield <<= 1; } } } /* * block operations * * check if a block is available */ int ffs_isblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h) { unsigned char mask; switch ((int)fs->fs_frag) { case 8: return (cp[h] == 0xff); case 4: mask = 0x0f << ((h & 0x1) << 2); return ((cp[h >> 1] & mask) == mask); case 2: mask = 0x03 << ((h & 0x3) << 1); return ((cp[h >> 2] & mask) == mask); case 1: mask = 0x01 << (h & 0x7); return ((cp[h >> 3] & mask) == mask); default: #ifdef _KERNEL panic("ffs_isblock"); #endif break; } return (0); } /* * check if a block is free */ int ffs_isfreeblock(struct fs *fs, u_char *cp, ufs1_daddr_t h) { switch ((int)fs->fs_frag) { case 8: return (cp[h] == 0); case 4: return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0); case 2: return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0); case 1: return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0); default: #ifdef _KERNEL panic("ffs_isfreeblock"); #endif break; } return (0); } /* * take a block out of the map */ void ffs_clrblock(struct fs *fs, u_char *cp, ufs1_daddr_t h) { switch ((int)fs->fs_frag) { case 8: cp[h] = 0; return; case 4: cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2)); return; case 2: cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1)); return; case 1: cp[h >> 3] &= ~(0x01 << (h & 0x7)); return; default: #ifdef _KERNEL panic("ffs_clrblock"); #endif break; } } /* * put a block into the map */ void ffs_setblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h) { switch ((int)fs->fs_frag) { case 8: cp[h] = 0xff; return; case 4: cp[h >> 1] |= (0x0f << ((h & 0x1) << 2)); return; case 2: cp[h >> 2] |= (0x03 << ((h & 0x3) << 1)); return; case 1: cp[h >> 3] |= (0x01 << (h & 0x7)); return; default: #ifdef _KERNEL panic("ffs_setblock"); #endif break; } } /* * Update the cluster map because of an allocation or free. * * Cnt == 1 means free; cnt == -1 means allocating. */ void ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_daddr_t blkno, int cnt) { int32_t *sump; int32_t *lp; u_char *freemapp, *mapp; int i, start, end, forw, back, map; u_int bit; if (fs->fs_contigsumsize <= 0) return; freemapp = cg_clustersfree(cgp); sump = cg_clustersum(cgp); /* * Allocate or clear the actual block. */ if (cnt > 0) setbit(freemapp, blkno); else clrbit(freemapp, blkno); /* * Find the size of the cluster going forward. */ start = blkno + 1; end = start + fs->fs_contigsumsize; if (end >= cgp->cg_nclusterblks) end = cgp->cg_nclusterblks; mapp = &freemapp[start / NBBY]; map = *mapp++; bit = 1U << (start % NBBY); for (i = start; i < end; i++) { if ((map & bit) == 0) break; if ((i & (NBBY - 1)) != (NBBY - 1)) { bit <<= 1; } else { map = *mapp++; bit = 1; } } forw = i - start; /* * Find the size of the cluster going backward. */ start = blkno - 1; end = start - fs->fs_contigsumsize; if (end < 0) end = -1; mapp = &freemapp[start / NBBY]; map = *mapp--; bit = 1U << (start % NBBY); for (i = start; i > end; i--) { if ((map & bit) == 0) break; if ((i & (NBBY - 1)) != 0) { bit >>= 1; } else { map = *mapp--; bit = 1U << (NBBY - 1); } } back = start - i; /* * Account for old cluster and the possibly new forward and * back clusters. */ i = back + forw + 1; if (i > fs->fs_contigsumsize) i = fs->fs_contigsumsize; sump[i] += cnt; if (back > 0) sump[back] -= cnt; if (forw > 0) sump[forw] -= cnt; /* * Update cluster summary information. */ lp = &sump[fs->fs_contigsumsize]; for (i = fs->fs_contigsumsize; i > 0; i--) if (*lp-- > 0) break; fs->fs_maxcluster[cgp->cg_cgx] = i; }