Comment Re:Excuses are false. This is a severe flaw. (Score 1) 830
Security. Consider the following scenario
1. Super-secure process opens private.txt 2. Super-secure process truncates private.txt 3. Super-secure process closes the file. 4. O/S re-allocates those disk blocks just freed by the truncate. 5. Nosy process opens a new file using the recently-reallocated blocks. 6. Nosy process reads through the undeleted data left by Super-secure process and sends them over a network connection to someplace bad. 7. Nosy process writes some random noise to the blocks. 8. O/S deletes the data on disk and then writes the data supplied by Nosy.
Ext4 does not make any guarantees about the erasure of file contents on disk. Even truncation as ext4 is doing it right now, doesn't actually overwrite truncated blocks with zeroes. So your whole point doesn't make sense at all.