Ext4 will normally overwrite blocks (btrfs, instead, is copy-on-write). The idea behind this patch set is that any blocks released from the file (as in the truncate case you mention) will be cleared/randomized by the filesystem code.
Copyright © 2017, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds