On Thu, Aug 17, 2023 at 07:52:55PM -0700, Eric Biggers wrote: > Obviously it's up to the system administrator; that should have been clear since > I suggested a sysctl. Sorry if I wasn't clear. The point is that there are > certain conventions for what is allowed to break the safety guarantees that the > kernel provides to userspace, which includes causing a kernel panic. Panics on > various problems are configured by /proc/sys/kernel/panic_*. So having to > opt-in to panic-on-error, or at least being able to opt-out, by setting a sysctl > seems natural. Whereas having mount() being able to automatically panic the > kernel with no way to opt-out seems like a violation of broader kernel > conventions, even if it happens to be "working as intended" in the ext4 context. The reason why a sysctl isn't really great is because the system administrator might want to configure the behavior on a per-file system basis. And you *can* configure it as a mount option, via "mount -o errors=continue" or "mount -o "errors=panic". The superblock setting is just the default if something isn't explicitly specified as a mount option (either on the command line or in /etc/fstab). So mount does not "automatically" panic the kernel, and there are *plenty* of ways to opt-out. You can use the mount option; you can run "tune2fs -e continue"; you can just !@#!?! run fsck.ext4 before mounting the file system. There are all ways of "opting out." Some of them, such as the last, is even considered best practice --- just as picking up a USB stick, or worse, a firewire drive, in a parking lot, and *not* plugging it into your laptop is considered best practice. - Ted
