Re: ext3 IO latency measurements (was: Linux 2.6.29)

From: Bill Nottingham
Date: Thu Mar 26 2009 - 14:25:30 EST


Linus Torvalds (torvalds@xxxxxxxxxxxxxxxxxxxx) said:
> > Linus Torvalds (torvalds@xxxxxxxxxxxxxxxxxxxx) said:
> > > And quite frankly, even if you then _manually_ put 'relatime' in
> > > /etc/fstab, the default Fedora install will totally ignore it. Why?
> > > Because it mounts the root partition while using initrd, and totally
> > > ignores /etc/fstab.
> >
> > It should honor /etc/fstab changes, if the initramfs is rebuilt
> > after the change is made. If it doesn't, that's a bug.
>
> Why the hell should I rebuild initramfs?

Well, it's got to find the root fs options somewhere. Pulling them
from the modified /etc/fstab in the root fs before you mount it, well...

As for why fstab options aren't applied with remount once the root
fs has been mounted, 1) historical reasons 2) someone specifies
'data=writeback' or similar can't-be-applied-with-remount flag in
/etc/fstab, and then mount refuses to remount it at all, and the
system refuses to boot. Arguably pilot error, of course.

Bill
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