Re: Quota file format [2.3 issue]

Jakub Jelinek (jj@sunsite.ms.mff.cuni.cz)
Tue, 13 Apr 1999 18:02:41 +0200 (CEST)

> Adding a 10 byte header will cause all subsequent 64bit values to be
> misaligned unless necessary padding is inserted between the values or
> the file is read to a buffer that is aligned so that the 64bit data
> entries align properly. Anyway, screwing this up can (will?) cause
> performance problems on 64bit architectures.

Only if someone is mmaping that file, but AFAIK noone does that, even the
kernel is not doing that. Everyone is using read/write and for that it does
not matter at all.

>
> I would think a better way to solve this is to look for an impossible
> value combination of the first (couple of) 32/64bit entries and use that
> as a magic marker for the new format.

There is none.

Cheers,
Jakub
___________________________________________________________________
Jakub Jelinek | jj@sunsite.mff.cuni.cz | http://sunsite.mff.cuni.cz
Administrator of SunSITE Czech Republic, MFF, Charles University
___________________________________________________________________
UltraLinux | http://ultra.linux.cz/ | http://ultra.penguin.cz/
Linux version 2.2.5 on a sparc64 machine (3958.37 BogoMips)
___________________________________________________________________

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