fs: fat: flush new directory cluster

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>
1 file changed