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authorkaashoek <kaashoek>2006-08-09 01:09:36 +0000
committerkaashoek <kaashoek>2006-08-09 01:09:36 +0000
commit241113985f7122c65345885dec02e008601ff7ef (patch)
treea3cfc32c380282f1a4d70e86041b6d6c15c519f4 /fs.c
parent0e84a0ec6e7893dad13dff9a958c5bc987b79c82 (diff)
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block bitmap
balloc
Diffstat (limited to 'fs.c')
-rw-r--r--fs.c74
1 files changed, 55 insertions, 19 deletions
diff --git a/fs.c b/fs.c
index 6774350..e194f59 100644
--- a/fs.c
+++ b/fs.c
@@ -16,6 +16,43 @@ struct spinlock inode_table_lock = { "inode_table" };
uint rootdev = 1;
+static uint
+balloc(uint dev)
+{
+ int b;
+ struct buf *bp;
+ struct superblock *sb;
+ int bi;
+ int size;
+ int ninodes;
+ uchar m;
+
+ bp = bread(dev, 1);
+ sb = (struct superblock *) bp->data;
+ size = sb->size;
+ ninodes = sb->ninodes;
+
+ for (b = 0; b < size; b++) {
+ if (b % BPB == 0) {
+ brelse(bp);
+ bp = bread(dev, BBLOCK(b, ninodes));
+ }
+ bi = b % BPB;
+ m = 0x1 << (bi % 8);
+ if ((bp->data[bi/8] & m) == 0) { // is block free?
+ break;
+ }
+ }
+ if (b >= size)
+ panic("balloc: out of blocks\n");
+
+ cprintf ("balloc: allocate block %d\n", b);
+ bp->data[bi/8] |= 0x1 << (bi % 8);
+ bwrite (dev, bp, BBLOCK(b, ninodes)); // mark it allocated on disk
+ return b;
+}
+
+
// returns an inode with busy set and incremented reference count.
struct inode *
iget(uint dev, uint inum)
@@ -51,7 +88,7 @@ iget(uint dev, uint inum)
release(&inode_table_lock);
- bp = bread(dev, inum / IPB + 2);
+ bp = bread(dev, IBLOCK(inum));
dip = &((struct dinode *)(bp->data))[inum % IPB];
nip->type = dip->type;
nip->major = dip->major;
@@ -76,12 +113,12 @@ ialloc(uint dev, short type)
struct buf *bp;
bp = bread(dev, 1);
- sb = (struct superblock *) bp;
+ sb = (struct superblock *) bp->data;
ninodes = sb->ninodes;
brelse(bp);
-
+
for (inum = 1; inum < ninodes; inum++) { // loop over inode blocks
- bp = bread(dev, inum / IPB + 2);
+ bp = bread(dev, IBLOCK(inum));
dip = &((struct dinode *)(bp->data))[inum % IPB];
if (dip->type == 0) { // a free inode
break;
@@ -90,13 +127,12 @@ ialloc(uint dev, short type)
}
if (inum >= ninodes) {
- cprintf ("ialloc: no inodes left\n");
- return 0;
+ panic ("ialloc: no inodes left\n");
}
cprintf ("ialloc: %d\n", inum);
dip->type = type;
- bwrite (dev, bp, inum / IPB + 2); // mark it allocated on the disk
+ bwrite (dev, bp, IBLOCK(inum)); // mark it allocated on the disk
brelse(bp);
ip = iget (dev, inum);
return ip;
@@ -108,14 +144,14 @@ iupdate (struct inode *ip)
struct buf *bp;
struct dinode *dip;
- bp = bread(ip->dev, ip->inum / IPB + 2);
+ bp = bread(ip->dev, IBLOCK(ip->inum));
dip = &((struct dinode *)(bp->data))[ip->inum % IPB];
dip->type = ip->type;
dip->major = ip->major;
dip->minor = ip->minor;
dip->nlink = ip->nlink;
dip->size = ip->size;
- bwrite (ip->dev, bp, ip->inum / IPB + 2); // mark it allocated on the disk
+ bwrite (ip->dev, bp, IBLOCK(ip->inum)); // mark it allocated on the disk
brelse(bp);
}
@@ -203,10 +239,10 @@ readi(struct inode *ip, void *xdst, uint off, uint n)
struct buf *bp;
while(n > 0 && off < ip->size){
- bp = bread(ip->dev, bmap(ip, off / 512));
+ bp = bread(ip->dev, bmap(ip, off / BSIZE));
n1 = min(n, ip->size - off);
- n1 = min(n1, 512 - (off % 512));
- memmove(dst, bp->data + (off % 512), n1);
+ n1 = min(n1, BSIZE - (off % BSIZE));
+ memmove(dst, bp->data + (off % BSIZE), n1);
n -= n1;
off += n1;
dst += n1;
@@ -241,10 +277,10 @@ namei(char *path)
return 0;
}
- for(off = 0; off < dp->size; off += 512){
- bp = bread(dp->dev, bmap(dp, off / 512));
+ for(off = 0; off < dp->size; off += BSIZE){
+ bp = bread(dp->dev, bmap(dp, off / BSIZE));
for(ep = (struct dirent *) bp->data;
- ep < (struct dirent *) (bp->data + 512);
+ ep < (struct dirent *) (bp->data + BSIZE);
ep++){
if(ep->inum == 0)
continue;
@@ -288,10 +324,10 @@ mknod(struct inode *dp, char *cp, short type, short major, short minor)
ip->major = major;
ip->minor = minor;
- for(off = 0; off < dp->size; off += 512) {
- bp = bread(dp->dev, bmap(dp, off / 512));
+ for(off = 0; off < dp->size; off += BSIZE) {
+ bp = bread(dp->dev, bmap(dp, off / BSIZE));
for(ep = (struct dirent *) bp->data;
- ep < (struct dirent *) (bp->data + 512);
+ ep < (struct dirent *) (bp->data + BSIZE);
ep++){
if(ep->inum == 0) {
goto found;
@@ -304,7 +340,7 @@ mknod(struct inode *dp, char *cp, short type, short major, short minor)
found:
ep->inum = ip->inum;
for(i = 0; i < DIRSIZ && cp[i]; i++) ep->name[i] = cp[i];
- bwrite (dp->dev, bp, bmap(dp, off/512)); // write directory
+ bwrite (dp->dev, bp, bmap(dp, off/BSIZE)); // write directory
brelse(bp);
iupdate (ip);
return ip;