/* * Allocate a block in a cylinder group. * * This algorithm implements the following policy: * 1) allocate the requested block. * 2) allocate a rotationally optimal block in the same cylinder. * 3) allocate the next available block on the block rotor for the * specified cylinder group. * Note that this routine only allocates fs_bsize blocks; these * blocks may be fragmented by the routine that allocates them. */ static daddr_t ffs_alloccgblk(struct inode *ip, struct buf *bp, daddr_t bpref) { struct cg *cgp; daddr_t blkno; int32_t bno; struct fs *fs = ip->i_fs; const int needswap = UFS_FSNEEDSWAP(fs); u_int8_t *blksfree_swap; cgp = (struct cg *)bp->b_data; blksfree_swap = cg_blksfree_swap(cgp, needswap); if (bpref == 0 || (uint32_t)dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) { bpref = ufs_rw32(cgp->cg_rotor, needswap); } else { bpref = blknum(fs, bpref); bno = dtogd(fs, bpref); /* * if the requested block is available, use it */ if (ffs_isblock(fs, blksfree_swap, fragstoblks(fs, bno))) goto gotit; } /* * Take the next available one in this cylinder group. */ bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag); if (bno < 0) return (0); cgp->cg_rotor = ufs_rw32(bno, needswap); gotit: blkno = fragstoblks(fs, bno); ffs_clrblock(fs, blksfree_swap, (long)blkno); ffs_clusteracct(fs, cgp, blkno, -1); ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap); fs->fs_cstotal.cs_nbfree--; fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--; fs->fs_fmod = 1; blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno; return (blkno); }
/* * Initialize a cylinder group. */ static void initcg(int cylno, time_t utime, const fsinfo_t *fsopts) { daddr_t cbase, dmax; int32_t i, j, d, dlower, dupper, blkno; struct ufs1_dinode *dp1; struct ufs2_dinode *dp2; int start; /* * Determine block bounds for cylinder group. * Allow space for super block summary information in first * cylinder group. */ cbase = cgbase(&sblock, cylno); dmax = cbase + sblock.fs_fpg; if (dmax > sblock.fs_size) dmax = sblock.fs_size; dlower = cgsblock(&sblock, cylno) - cbase; dupper = cgdmin(&sblock, cylno) - cbase; if (cylno == 0) dupper += howmany(sblock.fs_cssize, sblock.fs_fsize); memset(&acg, 0, sblock.fs_cgsize); acg.cg_time = utime; acg.cg_magic = CG_MAGIC; acg.cg_cgx = cylno; acg.cg_niblk = sblock.fs_ipg; acg.cg_initediblk = MIN(sblock.fs_ipg, 2 * INOPB(&sblock)); acg.cg_ndblk = dmax - cbase; if (sblock.fs_contigsumsize > 0) acg.cg_nclusterblks = acg.cg_ndblk >> sblock.fs_fragshift; start = &acg.cg_space[0] - (u_char *)(&acg.cg_firstfield); if (Oflag == 2) { acg.cg_iusedoff = start; } else { if (cylno == sblock.fs_ncg - 1) acg.cg_old_ncyl = howmany(acg.cg_ndblk, sblock.fs_fpg / sblock.fs_old_cpg); else acg.cg_old_ncyl = sblock.fs_old_cpg; acg.cg_old_time = acg.cg_time; acg.cg_time = 0; acg.cg_old_niblk = acg.cg_niblk; acg.cg_niblk = 0; acg.cg_initediblk = 0; acg.cg_old_btotoff = start; acg.cg_old_boff = acg.cg_old_btotoff + sblock.fs_old_cpg * sizeof(int32_t); acg.cg_iusedoff = acg.cg_old_boff + sblock.fs_old_cpg * sizeof(u_int16_t); } acg.cg_freeoff = acg.cg_iusedoff + howmany(sblock.fs_ipg, CHAR_BIT); if (sblock.fs_contigsumsize <= 0) { acg.cg_nextfreeoff = acg.cg_freeoff + howmany(sblock.fs_fpg, CHAR_BIT); } else { acg.cg_clustersumoff = acg.cg_freeoff + howmany(sblock.fs_fpg, CHAR_BIT) - sizeof(int32_t); acg.cg_clustersumoff = roundup(acg.cg_clustersumoff, sizeof(int32_t)); acg.cg_clusteroff = acg.cg_clustersumoff + (sblock.fs_contigsumsize + 1) * sizeof(int32_t); acg.cg_nextfreeoff = acg.cg_clusteroff + howmany(fragstoblks(&sblock, sblock.fs_fpg), CHAR_BIT); } if (acg.cg_nextfreeoff > sblock.fs_cgsize) { printf("Panic: cylinder group too big\n"); exit(37); } acg.cg_cs.cs_nifree += sblock.fs_ipg; if (cylno == 0) for (i = 0; i < ROOTINO; i++) { setbit(cg_inosused_swap(&acg, 0), i); acg.cg_cs.cs_nifree--; } if (cylno > 0) { /* * In cylno 0, beginning space is reserved * for boot and super blocks. */ for (d = 0, blkno = 0; d < dlower;) { ffs_setblock(&sblock, cg_blksfree_swap(&acg, 0), blkno); if (sblock.fs_contigsumsize > 0) setbit(cg_clustersfree_swap(&acg, 0), blkno); acg.cg_cs.cs_nbfree++; d += sblock.fs_frag; blkno++; } } if ((i = (dupper & (sblock.fs_frag - 1))) != 0) { acg.cg_frsum[sblock.fs_frag - i]++; for (d = dupper + sblock.fs_frag - i; dupper < d; dupper++) { setbit(cg_blksfree_swap(&acg, 0), dupper); acg.cg_cs.cs_nffree++; } } for (d = dupper, blkno = dupper >> sblock.fs_fragshift; d + sblock.fs_frag <= acg.cg_ndblk; ) {
setbit(cg_clustersfree_swap(&acg, 0), blkno); acg.cg_cs.cs_nbfree++; d += sblock.fs_frag; blkno++; } } if ((i = (dupper & (sblock.fs_frag - 1))) != 0) { acg.cg_frsum[sblock.fs_frag - i]++; for (d = dupper + sblock.fs_frag - i; dupper < d; dupper++) { setbit(cg_blksfree_swap(&acg, 0), dupper); acg.cg_cs.cs_nffree++; } } for (d = dupper, blkno = dupper >> sblock.fs_fragshift; d + sblock.fs_frag <= acg.cg_ndblk; ) { ffs_setblock(&sblock, cg_blksfree_swap(&acg, 0), blkno); if (sblock.fs_contigsumsize > 0) setbit(cg_clustersfree_swap(&acg, 0), blkno); acg.cg_cs.cs_nbfree++; d += sblock.fs_frag; blkno++; } if (d < acg.cg_ndblk) { acg.cg_frsum[acg.cg_ndblk - d]++; for (; d < acg.cg_ndblk; d++) { setbit(cg_blksfree_swap(&acg, 0), d); acg.cg_cs.cs_nffree++; } } if (sblock.fs_contigsumsize > 0) { int32_t *sump = cg_clustersum_swap(&acg, 0);
/* * Find a block of the specified size in the specified cylinder group. * * It is a panic if a request is made to find a block if none are * available. */ static int32_t ffs_mapsearch(struct fs *fs, struct cg *cgp, daddr_t bpref, int allocsiz) { int32_t bno; int start, len, loc, i; int blk, field, subfield, pos; int ostart, olen; const int needswap = UFS_FSNEEDSWAP(fs); /* * find the fragment by searching through the free block * map for an appropriate bit pattern */ if (bpref) start = dtogd(fs, bpref) / NBBY; else start = ufs_rw32(cgp->cg_frotor, needswap) / NBBY; len = howmany(fs->fs_fpg, NBBY) - start; ostart = start; olen = len; loc = scanc((u_int)len, (const u_char *)&cg_blksfree_swap(cgp, needswap)[start], (const u_char *)fragtbl[fs->fs_frag], (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); if (loc == 0) { len = start + 1; start = 0; loc = scanc((u_int)len, (const u_char *)&cg_blksfree_swap(cgp, needswap)[0], (const u_char *)fragtbl[fs->fs_frag], (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); if (loc == 0) { errx(1, "ffs_alloccg: map corrupted: start %d len %d offset %d %ld", ostart, olen, ufs_rw32(cgp->cg_freeoff, needswap), (long)cg_blksfree_swap(cgp, needswap) - (long)cgp); /* NOTREACHED */ } } bno = (start + len - loc) * NBBY; cgp->cg_frotor = ufs_rw32(bno, needswap); /* * found the byte in the map * sift through the bits to find the selected frag */ for (i = bno + NBBY; bno < i; bno += fs->fs_frag) { blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bno); blk <<= 1; field = around[allocsiz]; subfield = inside[allocsiz]; for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) { if ((blk & field) == subfield) return (bno + pos); field <<= 1; subfield <<= 1; } } errx(1, "ffs_alloccg: block not in map: bno %lld", (long long)bno); return (-1); }
/* * Free a block or fragment. * * The specified block or fragment is placed back in the * free map. If a fragment is deallocated, a possible * block reassembly is checked. */ void ffs_blkfree(struct inode *ip, daddr_t bno, long size) { struct cg *cgp; struct buf *bp; int32_t fragno, cgbno; int i, error, cg, blk, frags, bbase; struct fs *fs = ip->i_fs; const int needswap = UFS_FSNEEDSWAP(fs); if (size > fs->fs_bsize || fragoff(fs, size) != 0 || fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) { errx(1, "blkfree: bad size: bno %lld bsize %d size %ld", (long long)bno, fs->fs_bsize, size); } cg = dtog(fs, bno); if (bno >= fs->fs_size) { warnx("bad block %lld, ino %ju", (long long)bno, (uintmax_t)ip->i_number); return; } error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, &bp); if (error) { brelse(bp); return; } cgp = (struct cg *)bp->b_data; if (!cg_chkmagic_swap(cgp, needswap)) { brelse(bp); return; } cgbno = dtogd(fs, bno); if (size == fs->fs_bsize) { fragno = fragstoblks(fs, cgbno); if (!ffs_isfreeblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) { errx(1, "blkfree: freeing free block %lld", (long long)bno); } ffs_setblock(fs, cg_blksfree_swap(cgp, needswap), fragno); ffs_clusteracct(fs, cgp, fragno, 1); ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); fs->fs_cstotal.cs_nbfree++; fs->fs_cs(fs, cg).cs_nbfree++; } else { bbase = cgbno - fragnum(fs, cgbno); /* * decrement the counts associated with the old frags */ blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bbase); ffs_fragacct_swap(fs, blk, cgp->cg_frsum, -1, needswap); /* * deallocate the fragment */ frags = numfrags(fs, size); for (i = 0; i < frags; i++) { if (isset(cg_blksfree_swap(cgp, needswap), cgbno + i)) { errx(1, "blkfree: freeing free frag: block %lld", (long long)(cgbno + i)); } setbit(cg_blksfree_swap(cgp, needswap), cgbno + i); } ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); fs->fs_cstotal.cs_nffree += i; fs->fs_cs(fs, cg).cs_nffree += i; /* * add back in counts associated with the new frags */ blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bbase); ffs_fragacct_swap(fs, blk, cgp->cg_frsum, 1, needswap); /* * if a complete block has been reassembled, account for it */ fragno = fragstoblks(fs, bbase); if (ffs_isblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) { ufs_add32(cgp->cg_cs.cs_nffree, -fs->fs_frag, needswap); fs->fs_cstotal.cs_nffree -= fs->fs_frag; fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag; ffs_clusteracct(fs, cgp, fragno, 1); ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); fs->fs_cstotal.cs_nbfree++; fs->fs_cs(fs, cg).cs_nbfree++; } } fs->fs_fmod = 1; bdwrite(bp); }
/* * Determine whether a block can be allocated. * * Check to see if a block of the appropriate size is available, * and if it is, allocate it. */ static daddr_t ffs_alloccg(struct inode *ip, int cg, daddr_t bpref, int size) { struct cg *cgp; struct buf *bp; daddr_t bno, blkno; int error, frags, allocsiz, i; struct fs *fs = ip->i_fs; const int needswap = UFS_FSNEEDSWAP(fs); if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize) return (0); error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, &bp); if (error) { brelse(bp); return (0); } cgp = (struct cg *)bp->b_data; if (!cg_chkmagic_swap(cgp, needswap) || (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) { brelse(bp); return (0); } if (size == fs->fs_bsize) { bno = ffs_alloccgblk(ip, bp, bpref); bdwrite(bp); return (bno); } /* * check to see if any fragments are already available * allocsiz is the size which will be allocated, hacking * it down to a smaller size if necessary */ frags = numfrags(fs, size); for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++) if (cgp->cg_frsum[allocsiz] != 0) break; if (allocsiz == fs->fs_frag) { /* * no fragments were available, so a block will be * allocated, and hacked up */ if (cgp->cg_cs.cs_nbfree == 0) { brelse(bp); return (0); } bno = ffs_alloccgblk(ip, bp, bpref); bpref = dtogd(fs, bno); for (i = frags; i < fs->fs_frag; i++) setbit(cg_blksfree_swap(cgp, needswap), bpref + i); i = fs->fs_frag - frags; ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); fs->fs_cstotal.cs_nffree += i; fs->fs_cs(fs, cg).cs_nffree += i; fs->fs_fmod = 1; ufs_add32(cgp->cg_frsum[i], 1, needswap); bdwrite(bp); return (bno); } bno = ffs_mapsearch(fs, cgp, bpref, allocsiz); for (i = 0; i < frags; i++) clrbit(cg_blksfree_swap(cgp, needswap), bno + i); ufs_add32(cgp->cg_cs.cs_nffree, -frags, needswap); fs->fs_cstotal.cs_nffree -= frags; fs->fs_cs(fs, cg).cs_nffree -= frags; fs->fs_fmod = 1; ufs_add32(cgp->cg_frsum[allocsiz], -1, needswap); if (frags != allocsiz) ufs_add32(cgp->cg_frsum[allocsiz - frags], 1, needswap); blkno = cg * fs->fs_fpg + bno; bdwrite(bp); return blkno; }