https://bugzilla.kernel.org/show_bug.cgi?id=92271 --- Comment #3 from Alexander Holler <holler@xxxxxxxxxxxxx> --- It doesn't work for on FLASH based devices which have their own logic (e.g. SD-cards or SSDs, there "Secure Trim" is needed). And just overwriting a file by using open(); write(); close(); likely doesn't work with ext4 on traditional harddisks (or similiar blockdevices) too. Also I'm not sure about the last fact, as I'm not really aware of the internal workings of ext4. At least I've never read anywhere a statement, that by writing the same amount of bytes to a file as already there, the fs will for sure overwrite the same blocks on disk as already occupied/used by the file. So a special syscall or similiar is needed to instruct the fs to overwrite the same, already used blocks (even if they are stored only in the metadata because the file is small enough). -- You are receiving this mail because: You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html