diff options
Diffstat (limited to 'mkfs.c')
| -rw-r--r-- | mkfs.c | 93 |
1 files changed, 45 insertions, 48 deletions
@@ -13,18 +13,24 @@ #define static_assert(a, b) do { switch (0) case 0: case (a): ; } while (0) -int nblocks = (995-LOGSIZE); -int nlog = LOGSIZE; -int ninodes = 200; -int size = 1024; +#define SIZE 1000 +#define NINODES 200 + +// Disk layout: +// [ boot block | sb block | inode blocks | bit map | data blocks | log ] + +int nbitmap = SIZE/(BSIZE*8) + 1; +int ninodeblocks = NINODES / IPB + 1; +int nlog = LOGSIZE; +int nmeta; // Number of meta blocks (inode, bitmap, and 2 extra) +int nblocks; // Number of data blocks int fsfd; struct superblock sb; -char zeroes[512]; -uint freeblock; -uint usedblocks; -uint bitblocks; +char zeroes[BSIZE]; uint freeinode = 1; +uint freeblock; + void balloc(int); void wsect(uint, void*); @@ -63,7 +69,7 @@ main(int argc, char *argv[]) int i, cc, fd; uint rootino, inum, off; struct dirent de; - char buf[512]; + char buf[BSIZE]; struct dinode din; @@ -74,8 +80,8 @@ main(int argc, char *argv[]) exit(1); } - assert((512 % sizeof(struct dinode)) == 0); - assert((512 % sizeof(struct dirent)) == 0); + assert((BSIZE % sizeof(struct dinode)) == 0); + assert((BSIZE % sizeof(struct dirent)) == 0); fsfd = open(argv[1], O_RDWR|O_CREAT|O_TRUNC, 0666); if(fsfd < 0){ @@ -83,21 +89,19 @@ main(int argc, char *argv[]) exit(1); } - sb.size = xint(size); + nmeta = 2 + ninodeblocks + nbitmap; + nblocks = SIZE - nlog - nmeta; + + sb.size = xint(SIZE); sb.nblocks = xint(nblocks); // so whole disk is size sectors - sb.ninodes = xint(ninodes); + sb.ninodes = xint(NINODES); sb.nlog = xint(nlog); - bitblocks = size/(512*8) + 1; - usedblocks = ninodes / IPB + 3 + bitblocks; - freeblock = usedblocks; + printf("nmeta %d (boot, super, inode blocks %u, bitmap blocks %u) blocks %d log %u total %d\n", nmeta, ninodeblocks, nbitmap, nblocks, nlog, SIZE); - printf("used %d (bit %d ninode %zu) free %u log %u total %d\n", usedblocks, - bitblocks, ninodes/IPB + 1, freeblock, nlog, nblocks+usedblocks+nlog); + freeblock = nmeta; // the first free block that we can allocate - assert(nblocks + usedblocks + nlog == size); - - for(i = 0; i < nblocks + usedblocks + nlog; i++) + for(i = 0; i < SIZE; i++) wsect(i, zeroes); memset(buf, 0, sizeof(buf)); @@ -152,7 +156,7 @@ main(int argc, char *argv[]) din.size = xint(off); winode(rootino, &din); - balloc(usedblocks); + balloc(freeblock); exit(0); } @@ -160,30 +164,26 @@ main(int argc, char *argv[]) void wsect(uint sec, void *buf) { - if(lseek(fsfd, sec * 512L, 0) != sec * 512L){ + printf("seek to %d\n", sec * BSIZE); + if(lseek(fsfd, sec * BSIZE, 0) != sec * BSIZE){ perror("lseek"); exit(1); } - if(write(fsfd, buf, 512) != 512){ + if(write(fsfd, buf, BSIZE) != BSIZE){ perror("write"); exit(1); } } -uint -i2b(uint inum) -{ - return (inum / IPB) + 2; -} - void winode(uint inum, struct dinode *ip) { - char buf[512]; + char buf[BSIZE]; uint bn; struct dinode *dip; - bn = i2b(inum); + bn = IBLOCK(inum); + printf("winode %d\n", bn); rsect(bn, buf); dip = ((struct dinode*)buf) + (inum % IPB); *dip = *ip; @@ -193,11 +193,11 @@ winode(uint inum, struct dinode *ip) void rinode(uint inum, struct dinode *ip) { - char buf[512]; + char buf[BSIZE]; uint bn; struct dinode *dip; - bn = i2b(inum); + bn = IBLOCK(inum); rsect(bn, buf); dip = ((struct dinode*)buf) + (inum % IPB); *ip = *dip; @@ -206,11 +206,11 @@ rinode(uint inum, struct dinode *ip) void rsect(uint sec, void *buf) { - if(lseek(fsfd, sec * 512L, 0) != sec * 512L){ + if(lseek(fsfd, sec * BSIZE, 0) != sec * BSIZE){ perror("lseek"); exit(1); } - if(read(fsfd, buf, 512) != 512){ + if(read(fsfd, buf, BSIZE) != BSIZE){ perror("read"); exit(1); } @@ -233,17 +233,17 @@ ialloc(ushort type) void balloc(int used) { - uchar buf[512]; + uchar buf[BSIZE]; int i; printf("balloc: first %d blocks have been allocated\n", used); - assert(used < 512*8); - bzero(buf, 512); + assert(used < BSIZE*8); + bzero(buf, BSIZE); for(i = 0; i < used; i++){ buf[i/8] = buf[i/8] | (0x1 << (i%8)); } - printf("balloc: write bitmap block at sector %zu\n", ninodes/IPB + 3); - wsect(ninodes / IPB + 3, buf); + printf("balloc: write bitmap block at sector %d\n", ninodeblocks+2); + wsect(ninodeblocks+2, buf); } #define min(a, b) ((a) < (b) ? (a) : (b)) @@ -254,7 +254,7 @@ iappend(uint inum, void *xp, int n) char *p = (char*)xp; uint fbn, off, n1; struct dinode din; - char buf[512]; + char buf[BSIZE]; uint indirect[NINDIRECT]; uint x; @@ -262,32 +262,29 @@ iappend(uint inum, void *xp, int n) off = xint(din.size); while(n > 0){ - fbn = off / 512; + fbn = off / BSIZE; assert(fbn < MAXFILE); if(fbn < NDIRECT){ if(xint(din.addrs[fbn]) == 0){ din.addrs[fbn] = xint(freeblock++); - usedblocks++; } x = xint(din.addrs[fbn]); } else { if(xint(din.addrs[NDIRECT]) == 0){ // printf("allocate indirect block\n"); din.addrs[NDIRECT] = xint(freeblock++); - usedblocks++; } // printf("read indirect block\n"); rsect(xint(din.addrs[NDIRECT]), (char*)indirect); if(indirect[fbn - NDIRECT] == 0){ indirect[fbn - NDIRECT] = xint(freeblock++); - usedblocks++; wsect(xint(din.addrs[NDIRECT]), (char*)indirect); } x = xint(indirect[fbn-NDIRECT]); } - n1 = min(n, (fbn + 1) * 512 - off); + n1 = min(n, (fbn + 1) * BSIZE - off); rsect(x, buf); - bcopy(p, buf + off - (fbn * 512), n1); + bcopy(p, buf + off - (fbn * BSIZE), n1); wsect(x, buf); n -= n1; off += n1; |