Re: Question for XFS (mounting and clean bit)

[Martin Steigerwald <Martin@lichtvoll.de>]

Am Donnerstag 29 Mai 2008 schrieb Timothy Shimmin:
> Hi Andre,

Hi Timothy,

> I didn't follow all of this, sorry.
> When you ask about the "clean bit", I assume that you are referring
> to "clean XFS mount for filesystem".
> We effectively mark it clean if we do a successful unmount.
> As part of unmount, we write an unmount record into the xfs log.
> On the next mount we look for the head of the log and then for the
> unmount record nearby. If we find the unmount record then we know
> we have had a clean unmount previously, otherwise we replay the log.
> So it's really a question of doing an unmount versus resetting the
> box beforehand or forcing a shutdown beforehand.

But when is it dirtied? If the clean log entry is the actual "clean bit" I 
guess: When the first new entry is written in the log.

Does XFS write a log entry on mounting it already or only on the first 
real write? Or in other words if I mount a XFS filesystem without writing 
to it and reset the machine, would it be marked clean or dirty then? 
Hmmm, I could test this ;-).

If its only mounted read only, it shouldn't be marked dirty anyways.

Ciao,
-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
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