Re: [Mtools] FAT Dirty Flag support

[Alain Knaff]

Onno Benschop wrote:
> In Ubuntu I've stuck my hand up as interested in dealing with bugs to do
> with dosfstools. During that process it became apparent that the dirty
> flag for FAT is not being supported. Looking through the kernel source,
> I see no evidence of any such support either.
>
> Looking through the source of mtools I see references to a dirty flag
> implementation, and I see it being set and being cleared in fat.c,
> giving me hope that this has in fact been implemented.
>
> Can anyone here tell me if this is implemented for all the flavours of
> FAT, that is, FAT12, FAT16, FAT32, vFAT and xvFAT?
>
>
> Kind regards,

There is indeed a variable named fat_dirty in mtools. However, this does 
something else than what you mean. The variable says that mtools' 
*in-memory* copy of the FAT has not yet been written to disk (i.e. think 
"dirty cache" rather than "dirty filesystem").

The dirty flag in the FAT is not maintained, and for a program like 
mtools there would be little point to do so either, as the filesystem 
would only be dirty for very short periods of time (only while mcopy is 
running). For the in-kernel's VAT filesystem driver, it is a different 
matter, of course

Regards,

Alain