On Mon, Apr 22, 2019 at 03:08:09PM -0700, Elliott Mitchell wrote:
> Package: e2fsprogs
> Version: 1.43.4-2
> Severity: minor
>
> If being run on a system which uses MMP and they weren't unmounted
> cleanly, e2fsck will clear the MMP flags in order individually heavily
> slowing the check process.
>
> At a minimum when `e2fsck -a` is run, if it needs to clear one MMP flag
> it should check for MMP flags on other filesystems and attempt to clear
> them too.
>
> Needing two MMP waits (one for `fsck /` and one for `fsck -a`) is
> acceptable, 3+ is not.
What's the use case where you are using MMP on multiple file systems?
In most of the configurations that I've seen, each server will have
its own root file system, and the only thing which gets shared is a
single data partition.
In a boot sequence, e2fsck gets called separate for each partition. For
example:
% fsck -A -V -N
fsck from util-linux 2.33.1
Checking all file systems.
[/sbin/fsck.ext4 (1) -- /] fsck.ext4 /dev/mapper/lambda-root
[/sbin/fsck.vfat (1) -- /boot/efi] fsck.vfat /dev/nvme0n1p1
[/sbin/fsck.ext4 (1) -- /boot] fsck.ext4 /dev/nvme0n1p4
So e2fsck has no idea whether multiple file systems are being checked,
or only one. E2fsck is also not parsing /etc/fstab --- that's the job
of the fsck driver program, or if you are using systemd, the systemd
generator.
So at the risk of sounding like Steve Jobs --- if you are trying to
use multiple MMP file systems, you're probably holding it wrong. :-)
What is your use case; what are you trying to achieve, and how are
your systems setup? How are the disks connected to multiple servers?
For that matter, there could easily be configurations where just
because one MMP file system is no longer accessible to its primary
system, another MMP file system might still be accessible to its
primary system. (For example, one could imagine 3 systems, where each
system back up the other two, and so system #3 might be the backup for
systems #1 and #2. Just because one MMP file system --- say the one
for #1 --- has failed over, doesn't mean that the other MMP file
system --- which might be hooked up to system #2 --- should have its
MMP flag cleared.)
- Ted
