[systemd-devel] more verbose debug info than systemd.log_level=debug?

[Mantas Mikulėnas]

On Sun, Apr 9, 2017 at 2:17 PM, Lennart Poettering <lennart at poettering.net>
wrote:

> On Sun, 09.04.17 10:11, Michael Chapman (mike at very.puzzling.org) wrote:
>
> > Don't forget, they've provided an interface for software to use if it
> needs
> > more than the guarantees provided by sync. Informally speaking, the
> FIFREEZE
> > ioctl is intended to place a filesystem into a "fully consistent" state,
> not
> > just a "fully recoverable" state. (Formally it's all a bit hazy: POSIX
> > really doesn't guarantee anything with sync.)
>
> If FIFREEZE is a generic ioctl() supported by a number of different
> file systems I figure it would be much more OK with calling it.
>
> That said, are you sure FIFREEZE is really what we want there? it
> appears to also pause any further writes to disk (until FITHAW is
> called). Which isn't really what we are interested in here (note that
> we return back to the initrd after the umount spree and it shall be
> able to do the rest, and if it actually can do that, then the file
> systems should be able to unmount and that usually results in writes
> to disk...)
>
> So, I am still puzzled why the file system people think that "sync()"
> isn't supposed to actually sync things to disk... I mean, it appears
> the call is pretty much useless and it's traditional usage (which
> prominently is in sysvinit before reboot()) appears to be broken by
> their behaviour.
>
> Why bother with sync() at all, if it implies no guarantees? This is
> quite frankly bullshit...
>
> It appears to me that using /boot on a file system whith such broken
> sync() semantics is really not a safe thing to do, and people should
> probably only use something more reliable, i.e. ext2 or vfat where
> sync() actually works correctly...
>

It does? My /boot is vfat due to UEFI requirements, and it becomes
unbootable if you as much as sneeze near it – I've already had to repair it
thrice, after a sync and everything.

-- 
Mantas Mikulėnas <grawity at gmail.com>
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