1.1 --- a/src/fs.c	Sun Dec 11 11:12:30 2011 +0200
     1.2 +++ b/src/fs.c	Sun Dec 11 21:15:35 2011 +0200
     1.3 @@ -10,6 +10,13 @@
     1.4  #include "fs.h"
     1.5  #include "bdev.h"
     1.6  
     1.7 +#define BM_IDX(x)			((x) / 32)
     1.8 +#define BM_BIT(x)			((x) & 0x1f)
     1.9 +
    1.10 +#define BM_ISFREE(bm, x)	(((bm)[BM_IDX(x)] & (1 << BM_BIT(x))) == 0)
    1.11 +#define BM_SET(bm, x)		((bm)[BM_IDX(x)] |= (1 << BM_BIT(x)))
    1.12 +#define BM_CLR(bm, x)		((bm)[BM_IDX(x)] &= ~(1 << BM_BIT(x)))
    1.13 +
    1.14  
    1.15  int openfs(struct filesys *fs, dev_t dev);
    1.16  static int read_superblock(struct filesys *fs);
    1.17 @@ -156,3 +163,35 @@
    1.18  	free(buf);
    1.19  	return 0;
    1.20  }
    1.21 +
    1.22 +static int find_free(uint32_t *bm, int sz)
    1.23 +{
    1.24 +	int i;
    1.25 +	uint32_t ent;
    1.26 +
    1.27 +	for(i=0; i<=sz/32; i++) {
    1.28 +		if(bm[i] != 0xffffffff) {
    1.29 +			ent = i * 32;
    1.30 +			for(j=0; j<32; j++) {
    1.31 +				if(BM_ISFREE(bm, ent)) {
    1.32 +					return ent;
    1.33 +				}
    1.34 +			}
    1.35 +
    1.36 +			panic("shouldn't happen (in find_free:fs.c)");
    1.37 +		}
    1.38 +	}
    1.39 +
    1.40 +	return -1;
    1.41 +}
    1.42 +
    1.43 +static int alloc_inode(struct filesys *fs)
    1.44 +{
    1.45 +	int ino;
    1.46 +
    1.47 +	if((ino = find_free(fs->ibm, fs->ibm_count)) == -1) {
    1.48 +		return -1;
    1.49 +	}
    1.50 +	BM_SET(fs->ibm, ino);
    1.51 +	return 0;
    1.52 +}