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Ignore whitespace Rev 3587 → Rev 3588

/branches/dynload/uspace/srv/fs/fat/fat_fat.c
59,10 → 59,7
* @param bs Buffer holding the boot sector for the file.
* @param dev_handle Device handle of the device with the file.
* @param firstc First cluster to start the walk with.
* @param penult If non-NULL, output argument hodling the
* the penultimate cluster visited.
* @param ult If non-NULL, output argument holding the
* ultimate cluster visited.
* @param lastc If non-NULL, output argument hodling the last cluster number visited.
* @param max_clusters Maximum number of clusters to visit.
*
* @return Number of clusters seen during the walk.
69,7 → 66,7
*/
uint16_t
fat_cluster_walk(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
fat_cluster_t *penult, fat_cluster_t *ult, uint16_t max_clusters)
fat_cluster_t *lastc, uint16_t max_clusters)
{
block_t *b;
unsigned bps;
82,22 → 79,18
 
if (firstc == FAT_CLST_RES0) {
/* No space allocated to the file. */
if (ult)
*ult = firstc;
if (lastc)
*lastc = firstc;
return 0;
}
 
/* At this point, the meaning of penult is not well-defined. */
if (penult)
*penult = FAT_CLST_RES0;
 
while (clst < FAT_CLST_LAST1 && clusters < max_clusters) {
unsigned fsec; /* sector offset relative to FAT1 */
bn_t fsec; /* sector offset relative to FAT1 */
unsigned fidx; /* FAT1 entry index */
 
assert(clst >= FAT_CLST_FIRST);
if (penult)
*penult = clst; /* remember the penultimate cluster */
if (lastc)
*lastc = clst; /* remember the last cluster number */
fsec = (clst * sizeof(fat_cluster_t)) / bps;
fidx = clst % (bps / sizeof(fat_cluster_t));
/* read FAT1 */
108,8 → 101,8
clusters++;
}
 
if (ult)
*ult = clst;
if (lastc && clst < FAT_CLST_LAST1)
*lastc = clst;
 
return clusters;
}
120,13 → 113,13
* @param dev_handle Device handle of the file system.
* @param firstc First cluster used by the file. Can be zero if the file
* is empty.
* @param offset Offset in blocks.
* @param bn Block number.
*
* @return Block structure holding the requested block.
*/
block_t *
_fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
off_t offset)
bn_t bn)
{
block_t *b;
unsigned bps;
136,7 → 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);
149,23 → 142,22
 
if (firstc == FAT_CLST_ROOT) {
/* root directory special case */
assert(offset < rds);
b = block_get(dev_handle, rscnt + bs->fatcnt * sf + offset);
assert(bn < rds);
b = block_get(dev_handle, rscnt + bs->fatcnt * sf + bn);
return b;
}
 
max_clusters = offset / bs->spc;
clusters = fat_cluster_walk(bs, dev_handle, firstc, NULL, &lastc,
max_clusters = bn / bs->spc;
clusters = fat_cluster_walk(bs, dev_handle, firstc, &lastc,
max_clusters);
assert(clusters == max_clusters);
 
b = block_get(dev_handle, ssa + (lastc - FAT_CLST_FIRST) * bs->spc +
offset % bs->spc);
bn % bs->spc);
 
return b;
}
 
 
/** Fill the gap between EOF and a new file position.
*
* @param bs Buffer holding the boot sector for nodep.
210,16 → 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;
256,7 → 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]);
}
}
340,7 → 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);
}
348,9 → 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.
*/
360,8 → 402,8
fat_cluster_t lcl;
uint8_t fatno;
 
if (fat_cluster_walk(bs, nodep->idx->dev_handle, nodep->firstc, &lcl,
NULL, (uint16_t) -1) == 0) {
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);
nodep->dirty = true; /* need to sync node */
369,9 → 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 chopped 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);
}
}
 
/**
* @}
*/