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fs: fat: flush new directory cluster

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When handling long file names directory entries may be split over multiple
clusters. We must make sure that new clusters are zero filled on disk.

When allocating a new cluster for a directory flush it.

The flushing should be executed before updating the FAT. This way if
flushing fails, we still have a valid directory structure.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Heinrich Schuchardt 2020-11-26 19:06:55 +01:00
parent 7557c84855
commit 569b0e1938
1 changed files with 19 additions and 9 deletions
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28
fs/fat/fat_write.c
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@ -738,17 +738,32 @@ static int find_empty_cluster(fsdata *mydata)
return entry;
}
/*
* Allocate a cluster for additional directory entries
/**
* new_dir_table() - allocate a cluster for additional directory entries
*
* @itr: directory iterator
* Return: 0 on success, -EIO otherwise
*/
static int new_dir_table(fat_itr *itr)
{
fsdata *mydata = itr->fsdata;
int dir_newclust = 0;
int dir_oldclust = itr->clust;
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
dir_newclust = find_empty_cluster(mydata);
set_fatent_value(mydata, itr->clust, dir_newclust);
/*
* Flush before updating FAT to ensure valid directory structure
* in case of failure.
*/
itr->clust = dir_newclust;
itr->next_clust = dir_newclust;
memset(itr->block, 0x00, bytesperclust);
if (flush_dir(itr))
return -EIO;
set_fatent_value(mydata, dir_oldclust, dir_newclust);
if (mydata->fatsize == 32)
set_fatent_value(mydata, dir_newclust, 0xffffff8);
else if (mydata->fatsize == 16)
@ -756,13 +771,8 @@ static int new_dir_table(fat_itr *itr)
else if (mydata->fatsize == 12)
set_fatent_value(mydata, dir_newclust, 0xff8);
itr->clust = dir_newclust;
itr->next_clust = dir_newclust;
if (flush_dirty_fat_buffer(mydata) < 0)
return -1;
memset(itr->block, 0x00, bytesperclust);
return -EIO;
itr->dent = (dir_entry *)itr->block;
itr->last_cluster = 1;