diff options
Diffstat (limited to 'fs.c')
| -rw-r--r-- | fs.c | 97 |
1 files changed, 42 insertions, 55 deletions
@@ -41,13 +41,9 @@ iinit(void) static uint balloc(uint dev) { - int b; + int b, bi, m, ninodes, size; struct buf *bp; struct superblock *sb; - int bi = 0; - int size; - int ninodes; - uchar m; bp = bread(dev, 1); sb = (struct superblock*) bp->data; @@ -62,16 +58,13 @@ balloc(uint dev) bi = b % BPB; m = 0x1 << (bi % 8); if((bp->data[bi/8] & m) == 0) { // is block free? - break; + bp->data[bi/8] |= 0x1 << (bi % 8); + bwrite(bp, BBLOCK(b, ninodes)); // mark it allocated on disk + brelse(bp); + return b; } } - if(b >= size) - panic("balloc: out of blocks"); - - bp->data[bi/8] |= 0x1 << (bi % 8); - bwrite(bp, BBLOCK(b, ninodes)); // mark it allocated on disk - brelse(bp); - return b; + panic("balloc: out of blocks"); } // Free a disk block. @@ -80,9 +73,7 @@ bfree(int dev, uint b) { struct buf *bp; struct superblock *sb; - int bi; - int ninodes; - uchar m; + int bi, m, ninodes; bp = bread(dev, 1); sb = (struct superblock*) bp->data; @@ -96,8 +87,8 @@ bfree(int dev, uint b) bp = bread(dev, BBLOCK(b, ninodes)); bi = b % BPB; - m = ~(0x1 << (bi %8)); - bp->data[bi/8] &= m; + m = 0x1 << (bi % 8); + bp->data[bi/8] &= ~m; bwrite(bp, BBLOCK(b, ninodes)); // mark it free on disk brelse(bp); } @@ -176,7 +167,7 @@ iupdate(struct inode *ip) dip->nlink = ip->nlink; dip->size = ip->size; memmove(dip->addrs, ip->addrs, sizeof(ip->addrs)); - bwrite(bp, IBLOCK(ip->inum)); // mark it allocated on the disk + bwrite(bp, IBLOCK(ip->inum)); brelse(bp); } @@ -186,7 +177,7 @@ struct inode* ialloc(uint dev, short type) { struct inode *ip; - struct dinode *dip = 0; + struct dinode *dip; struct superblock *sb; int ninodes; int inum; @@ -290,12 +281,13 @@ itrunc(struct inode *ip) { int i, j; struct buf *inbp; + uint *a; for(i = 0; i < NADDRS; i++) { if(ip->addrs[i] != 0) { if(i == INDIRECT) { inbp = bread(ip->dev, ip->addrs[INDIRECT]); - uint *a = (uint*) inbp->data; + a = (uint*)inbp->data; for(j = 0; j < NINDIRECT; j++) { if(a[j] != 0) { bfree(ip->dev, a[j]); @@ -372,7 +364,7 @@ stati(struct inode *ip, struct stat *st) int readi(struct inode *ip, char *dst, uint off, uint n) { - uint target = n, n1; + uint target, n1; struct buf *bp; if(ip->type == T_DEV) { @@ -381,6 +373,7 @@ readi(struct inode *ip, char *dst, uint off, uint n) return devsw[ip->major].read(ip->minor, dst, n); } + target = n; while(n > 0 && off < ip->size){ bp = bread(ip->dev, bmap(ip, off / BSIZE)); n1 = min(n, ip->size - off); @@ -435,45 +428,39 @@ newblock(struct inode *ip, uint lbn) int writei(struct inode *ip, char *addr, uint off, uint n) { + struct buf *bp; + int r, m, lbn; + if(ip->type == T_DEV) { if(ip->major < 0 || ip->major >= NDEV || !devsw[ip->major].write) return -1; return devsw[ip->major].write(ip->minor, addr, n); - } else if(ip->type == T_FILE || ip->type == T_DIR) { - struct buf *bp; - int r = 0; - int m; - int lbn; - while(r < n) { - lbn = off / BSIZE; - if(lbn >= MAXFILE) - return r; - if(newblock(ip, lbn) < 0) { - cprintf("newblock failed\n"); - return r; - } - m = min(BSIZE - off % BSIZE, n-r); - bp = bread(ip->dev, bmap(ip, lbn)); - memmove(bp->data + off % BSIZE, addr, m); - bwrite(bp, bmap(ip, lbn)); - brelse(bp); - r += m; - off += m; - } - if(r > 0) { - if(off > ip->size) { - if(ip->type == T_DIR) - ip->size = ((off / BSIZE) + 1) * BSIZE; - else - ip->size = off; - } - iupdate(ip); + } + + for(r=0; r<n; ) { + lbn = off / BSIZE; + if(lbn >= MAXFILE) + return r; + if(newblock(ip, lbn) < 0) { + cprintf("newblock failed\n"); + return r; } - return r; - } else { - panic("writei: unknown type"); - return 0; + m = min(BSIZE - off % BSIZE, n-r); + bp = bread(ip->dev, bmap(ip, lbn)); + memmove(bp->data + off % BSIZE, addr, m); + bwrite(bp, bmap(ip, lbn)); + brelse(bp); + r += m; + off += m; + } + if(r > 0 && off > ip->size) { + if(ip->type == T_DIR) + ip->size = ((off / BSIZE) + 1) * BSIZE; + else + ip->size = off; + iupdate(ip); } + return r; } // Skip over the next path element in path, |