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fs: fat: fat_find_empty_dentries()

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Provide a function to find a series of empty directory entries.

The current directory is scanned for deleted entries.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Heinrich Schuchardt 2020-11-22 09:58:44 +01:00
parent 569b0e1938
commit 32a5f887c4
1 changed files with 61 additions and 1 deletions
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62
fs/fat/fat_write.c
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@ -21,6 +21,7 @@
#include "fat.c"
static dir_entry *find_directory_entry(fat_itr *itr, char *filename);
static int new_dir_table(fat_itr *itr);
/* Characters that may only be used in long file names */
static const char LONG_ONLY_CHARS[] = "+,;=[]";
@ -250,6 +251,66 @@ static int flush_dirty_fat_buffer(fsdata *mydata)
return 0;
}
/**
* fat_find_empty_dentries() - find a sequence of available directory entries
*
* @itr: directory iterator
* @count: number of directory entries to find
* Return: 0 on success or negative error number
*/
static int __maybe_unused fat_find_empty_dentries(fat_itr *itr, int count)
{
unsigned int cluster;
dir_entry *dent;
int remaining;
unsigned int n = 0;
int ret;
ret = fat_move_to_cluster(itr, itr->start_clust);
if (ret)
return ret;
for (;;) {
if (!itr->dent) {
log_debug("Not enough directory entries available\n");
return -ENOSPC;
}
switch (itr->dent->name[0]) {
case 0x00:
case DELETED_FLAG:
if (!n) {
/* Remember first deleted directory entry */
cluster = itr->clust;
dent = itr->dent;
remaining = itr->remaining;
}
++n;
if (n == count)
goto out;
break;
default:
n = 0;
break;
}
next_dent(itr);
if (!itr->dent &&
(!itr->is_root || itr->fsdata->fatsize == 32) &&
new_dir_table(itr))
return -ENOSPC;
}
out:
/* Position back to first directory entry */
if (itr->clust != cluster) {
ret = fat_move_to_cluster(itr, cluster);
if (ret)
return ret;
}
itr->dent = dent;
itr->remaining = remaining;
return 0;
}
/*
* Set the file name information from 'name' into 'slotptr',
*/
@ -319,7 +380,6 @@ name11_12:
return 1;
}
static int new_dir_table(fat_itr *itr);
static int flush_dir(fat_itr *itr);
/**