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Subject: Re: file system block size
From: Badari Pulavarty <pbadari@gmail.com>
To: Bob Copeland <email@bobcopeland.com>
Cc: Anton Altaparmakov <aia21@cam.ac.uk>, Roushan Ali <roushan.ali@gmail.com>,
       Nathan Scott <nathans@sgi.com>, lkml <linux-kernel@vger.kernel.org>
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Date: Tue, 18 Oct 2005 08:30:24 -0700
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On Tue, 2005-10-18 at 11:12 -0400, Bob Copeland wrote:
> > Indeed, it makes everything harder.  Have a look at ntfs in the kernel
> > which has to cope with file system block sizes between 512 bytes and
> > several hundred kiB (at least they are in powers of two thank
> > goodness...).  You end up not being able to use a lot of generic
> > functions as you for example need to lock multiple pages which needs to
> > be ordered correctly, etc...  If you look at the latest -mm kernel, the
> > ntfs driver there has file write(2) support for any cluster size and you
> > will see an example of the multiple page locking problem solution there.
> 
> Any chance this will make it into common code?  I also need it for my
> filesystem driver (here: http://bobcopeland.com/karma/).  So far I've
> only done read side which is not too bad, but as you say writing makes
> things complicated.
> 
> That, and the extent-supporting mpage_readpages would make me a happy person.

Can you elaborate ? What would you like to see in mpage_readpages() ?
Christoph recently posted patches to add support for getblocks() in
mpage_readpages().  What else do you need ?


Thanks,
Badari

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