Re: [prepatch] address_space-based writeback

[Anton Altaparmakov]

At 16:53 27/04/02, Jan Harkes wrote:
>On Fri, Apr 12, 2002 at 08:57:17AM +0100, Anton Altaparmakov wrote:
> > Yet, this really begs the question of defining the concept of a file. I am
> > quite happy with files being the io entity in ntfs. It is just that each
> > file in ntfs can contain loads of different data holding attributes which
> > are all worth placing in address spaces. Granted, a dummy inode could be
> > setup for each of those which just means a lot of wasted ram but ntfs is
> > not that important so I have to take the penalty there. But if I also need
> > unique inode numbers in those dummy inodes then the overhead is becoming
> > very, very high...
>
>You could have all additional IO streams use the same inode number and
>use iget4. Several inodes can have the same i_ino and the additional
>argument would be a stream identifier that selects the correct 'IO
>identity'.

Great idea! I quickly looked into the implementation details and using 
iget4/read_inode2 perfectly reconciles my ideas of using an address space 
mapping for each ntfs attribute with the kernels requirement of using 
inodes as the i/o entity by allowing a clean and unique mapping between 
multiple inodes with the same inode numbers and their attributes and 
address spaces.

I need to work out exactly how to do it but I will definitely go that way. 
That will make everything nice and clean and get rid of the existing 
kludges of passing around other types of objects instead of struct file * 
to my various readpage functions. Also I will be able to have fewer 
readpage functions... (-:

Thanks for the suggestion!

Best regards,

Anton