Symbolic link creation fails after file deletion (#58)

symptom

When executing the following cmd

echo "run:touch file1"
touch file1

echo "run:ln -s file1 symlink"
ln -s file1 symlink

echo "run:rm -f symlink"
rm -f symlink

echo "run:touch symlink"
touch symlink

the touch symlink command return "No space left on device"

triage

How does the event be trigger? The touch command call "simplefs_new_inode"