Pardon me for a naïve question, but this "secure delete" will only delete/wipe/overwrite the current version of a file, right? I won't even pretend I know whether a write to a currently existing file may end up using an entirely different set of blocks (so the later secure won't touch the initial set), but assuming the file shrinks in the meantime, an I right in guessing that the blocks between the previous EOF and the new EOF will be untouched?
Posted Oct 13, 2011 12:14 UTC (Thu) by corbet (editor, #1)
[Link]
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.