129,7 → 129,7 |
unsigned sf; |
unsigned ssa; /* size of the system area */ |
unsigned clusters, max_clusters; |
fat_cluster_t lastc, clst = firstc; |
fat_cluster_t lastc; |
|
bps = uint16_t_le2host(bs->bps); |
rscnt = uint16_t_le2host(bs->rscnt); |
158,7 → 158,6 |
return b; |
} |
|
|
/** Fill the gap between EOF and a new file position. |
* |
* @param bs Buffer holding the boot sector for nodep. |
203,16 → 202,43 |
} |
} |
|
/** Mark cluster in one instance of FAT. |
/** Get cluster from the first FAT. |
* |
* @param bs Buffer holding the boot sector for the file system. |
* @param dev_handle Device handle for the file system. |
* @param clst Cluster which to get. |
* |
* @return Value found in the cluster. |
*/ |
fat_cluster_t |
fat_get_cluster(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t clst) |
{ |
block_t *b; |
uint16_t bps; |
uint16_t rscnt; |
fat_cluster_t *cp, value; |
|
bps = uint16_t_le2host(bs->bps); |
rscnt = uint16_t_le2host(bs->rscnt); |
|
b = block_get(dev_handle, rscnt + (clst * sizeof(fat_cluster_t)) / bps); |
cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t)); |
value = uint16_t_le2host(*cp); |
block_put(b); |
|
return value; |
} |
|
/** Set cluster in one instance of FAT. |
* |
* @param bs Buffer holding the boot sector for the file system. |
* @param dev_handle Device handle for the file system. |
* @param fatno Number of the FAT instance where to make the change. |
* @param clst Cluster which is to be marked. |
* @param value Value mark the cluster with. |
* @param clst Cluster which is to be set. |
* @param value Value to set the cluster with. |
*/ |
void |
fat_mark_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno, |
fat_set_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno, |
fat_cluster_t clst, fat_cluster_t value) |
{ |
block_t *b; |
249,7 → 275,7 |
|
for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) { |
for (c = 0; c < nclsts; c++) { |
fat_mark_cluster(bs, dev_handle, fatno, lifo[c], |
fat_set_cluster(bs, dev_handle, fatno, lifo[c], |
c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]); |
} |
} |
333,7 → 359,7 |
* we have allocated so far. |
*/ |
while (found--) { |
fat_mark_cluster(bs, dev_handle, FAT1, lifo[found], |
fat_set_cluster(bs, dev_handle, FAT1, lifo[found], |
FAT_CLST_RES0); |
} |
|
341,9 → 367,32 |
return ENOSPC; |
} |
|
/** Free clusters forming a cluster chain in all copies of FAT. |
* |
* @param bs Buffer hodling the boot sector of the file system. |
* @param dev_handle Device handle of the file system. |
* @param firstc First cluster in the chain which is to be freed. |
*/ |
void |
fat_free_clusters(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc) |
{ |
unsigned fatno; |
fat_cluster_t nextc; |
|
/* Mark all clusters in the chain as free in all copies of FAT. */ |
while (firstc < FAT_CLST_LAST1) { |
nextc = fat_get_cluster(bs, dev_handle, firstc); |
assert(nextc >= FAT_CLST_FIRST && nextc < FAT_CLST_BAD); |
for (fatno = FAT1; fatno < bs->fatcnt; fatno++) |
fat_set_cluster(bs, dev_handle, fatno, firstc, |
FAT_CLST_RES0); |
firstc = nextc; |
} |
} |
|
/** Append a cluster chain to the last file cluster in all FATs. |
* |
* @param bs Buffer holding boot sector of the file system. |
* @param bs Buffer holding the boot sector of the file system. |
* @param nodep Node representing the file. |
* @param mcl First cluster of the cluster chain to append. |
*/ |
353,7 → 402,7 |
fat_cluster_t lcl; |
uint8_t fatno; |
|
if (fat_cluster_walk(bs, nodep->idx->dev_handle, nodep->firstc, &lcl, |
if (fat_cluster_walk(bs, dev_handle, nodep->firstc, &lcl, |
(uint16_t) -1) == 0) { |
/* No clusters allocated to the node yet. */ |
nodep->firstc = host2uint16_t_le(mcl); |
362,9 → 411,40 |
} |
|
for (fatno = FAT1; fatno < bs->fatcnt; fatno++) |
fat_mark_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl); |
fat_set_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl); |
} |
|
/** Chop off node clusters in all copies of FAT. |
* |
* @param bs Buffer holding the boot sector of the file system. |
* @param nodep FAT node where the chopping will take place. |
* @param lastc Last cluster which will remain in the node. If this |
* argument is FAT_CLST_RES0, then all clusters will |
* be choped off. |
*/ |
void fat_chop_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t lastc) |
{ |
dev_handle_t dev_handle = nodep->idx->dev_handle; |
if (lastc == FAT_CLST_RES0) { |
/* The node will have zero size and no clusters allocated. */ |
fat_free_clusters(bs, dev_handle, nodep->firstc); |
nodep->firstc = FAT_CLST_RES0; |
nodep->dirty = true; /* need to sync node */ |
} else { |
fat_cluster_t nextc; |
unsigned fatno; |
|
nextc = fat_get_cluster(bs, dev_handle, lastc); |
|
/* Terminate the cluster chain in all copies of FAT. */ |
for (fatno = FAT1; fatno < bs->fatcnt; fatno++) |
fat_set_cluster(bs, dev_handle, fatno, lastc, FAT_CLST_LAST1); |
|
/* Free all following clusters. */ |
fat_free_clusters(bs, dev_handle, nextc); |
} |
} |
|
/** |
* @} |
*/ |