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Make free cluster search circular in case the FSINFO/DPB value is not correct

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and there is a free cluster before the given value.
Also, when calculating free space we get the first free cluster for free.


git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@1632 6ac86273-5f31-0410-b378-82cca8765d1b
This commit is contained in:
Bart Oldeman 2011-06-13 16:29:14 +00:00
parent aab06b8a4d
commit ac7f32468b
1 changed files with 32 additions and 17 deletions
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49
kernel/fatfs.c
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@ -692,7 +692,7 @@ time dos_gettime(void)
/* */
STATIC CLUSTER find_fat_free(f_node_ptr fnp)
{
REG CLUSTER idx, size;
REG CLUSTER idx, size, cluster;
struct dpb FAR *dpbp = fnp->f_dpb;
#ifdef DISPLAY_GETBLOCK
@ -717,39 +717,41 @@ STATIC CLUSTER find_fat_free(f_node_ptr fnp)
/* Search the FAT table looking for the first free */
/* entry. */
for (; idx <= size; idx++)
cluster = idx;
for (;;)
{
#ifdef CHECK_FAT_DURING_CLUSTER_ALLOC /* slower but nice side effect ;-) */
if (next_cluster(dpbp, idx) == FREE)
#else
if (is_free_cluster(dpbp, idx))
#endif
{
cluster = idx;
break;
}
idx++;
/* wrap the search just in case there are free clusters before */
/* dpbp->dpb_(x)cluster (the fsinfo entry is just a hint!) */
if (idx > size) idx = 2;
if (idx == cluster) {
/* No empty clusters, disk is FULL! */
cluster = UNKNCLUSTER;
idx = LONG_LAST_CLUSTER;
break;
}
}
#ifdef WITHFAT32
if (ISFAT32(dpbp))
{
dpbp->dpb_xcluster = idx;
if (idx > size)
{
/* No empty clusters, disk is FULL! */
dpbp->dpb_xcluster = UNKNCLUSTER;
idx = LONG_LAST_CLUSTER;
}
dpbp->dpb_xcluster = cluster;
/* return the free entry */
write_fsinfo(dpbp);
return idx;
}
#endif
dpbp->dpb_cluster = (UWORD)idx;
if ((UWORD)idx > (UWORD)size)
{
/* No empty clusters, disk is FULL! */
dpbp->dpb_cluster = UNKNCLUSTER;
idx = LONG_LAST_CLUSTER;
}
dpbp->dpb_cluster = (UWORD)cluster;
/* return the free entry */
return idx;
}
@ -1446,7 +1448,7 @@ CLUSTER dos_free(struct dpb FAR * dpbp)
/* There's an unwritten rule here. All fs */
/* cluster start at 2 and run to max_cluster+2 */
REG CLUSTER i;
REG CLUSTER cnt = 0;
REG CLUSTER cnt;
CLUSTER max_cluster = dpbp->dpb_size;
#ifdef WITHFAT32
@ -1461,6 +1463,7 @@ CLUSTER dos_free(struct dpb FAR * dpbp)
if (dpbp->dpb_nfreeclst != UNKNCLSTFREE)
return dpbp->dpb_nfreeclst;
cnt = 0;
for (i = 2; i <= max_cluster; i++)
{
#ifdef CHECK_FAT_DURING_SPACE_CHECK /* slower but nice side effect ;-) */
@ -1468,7 +1471,19 @@ CLUSTER dos_free(struct dpb FAR * dpbp)
#else
if (is_free_cluster(dpbp, i))
#endif
{
if (cnt == 0)
{
/* update first free cluster number */
#ifdef WITHFAT32
if (ISFAT32(dpbp))
dpbp->dpb_xcluster = i;
else
#endif
dpbp->dpb_cluster = (UWORD)i;
}
++cnt;
}
}
#ifdef WITHFAT32
if (ISFAT32(dpbp))