Re: (fwd) Re: [RFC] mount flag "direct"

From: Anton Altaparmakov (aia21@cantab.net)
Date: Fri Sep 06 2002 - 14:32:50 EST


At 18:33 06/09/02, Daniel Phillips wrote:
>On Friday 06 September 2002 19:20, Anton Altaparmakov wrote:
> > As of very recently, Andrew Morton introduced an optimization to this with
> > the get_blocks() interface in 2.5 kernels. Now the file system, when doing
> > direct_IO at least, returns to the VFS the requested block position _and_
> > the size of the block. So the VFS now gains in power in that it only needs
> > to ask for each block once as it is now aware of the size of the block.
> >
> > But still, even with this optimization, the VFS still asks the FS for each
> > block, and then the FS has to lookup each block.
>
>Well, it takes no great imagination to see the progression: get_blocks
>acts on extents instead of arrays of blocks. Expect to see that around
>the 2.7 timeframe.

Isn't that just a matter of terminology? Whether you are calling the
things "variable sized blocks" or "extents" they are still the same thing,
no? So I would say, get_blocks() acts on extents right now. (-: [I may be
missing your point in which case a small explanation would be appreciated...]

Cheers,

         Anton

-- 
   "I've not lost my mind. It's backed up on tape somewhere." - Unknown
-- 
Anton Altaparmakov <aia21 at cantab.net> (replace at with @)
Linux NTFS Maintainer / IRC: #ntfs on irc.openprojects.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/

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