Re: New filesystem for Linux

[Mikulas Patocka]

On Sat, 4 Nov 2006, Grzegorz Kulewski wrote:

> On Sat, 4 Nov 2006, Mikulas Patocka wrote:
> > > >  If it overflows, it increases crash count instead. So really you have > 
> > > 2^47
> > > >  transactions or 65536 crashes and 2^31 transactions between each crash.
> > >
> > >  it seems to me that you only need to be able to represent a range of the
> > >  most recent 65536 crashes... and could have an online process which goes
> > >  about "refreshing" old objects to move them forward to the most recent
> > >  crash state.  as long as you know the minimm on-disk crash count you can
> > >  use it as an offset.
> >
> > After 65536 crashes you have to run spadfsck --reset-crash-counts. Maybe I 
> > add that functionality to kernel driver too, so that it will be formally 
> > corect.
>
> Is there any reason you can not make these fields 64 or even 128 bits in size 
> to increase these "limits" dramatically?

Yes

First --- you need a table of 65536 entries. Table of 4G entries would be 
too large.
Second --- it will make structures larger and thus some operations (like 
scanning directory with find) slower.

Mikulas
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