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Date: Wed, 2 May 2007 15:34:56 -0400
From: Theodore Tso <tytso@mit.edu>
To: Jeremy Allison <jra@samba.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       "Cabot, Mason B" <mason.b.cabot@intel.com>,
       linux-kernel@vger.kernel.org, tridge@samba.com
Subject: Re: Ext3 vs NTFS performance
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On Wed, May 02, 2007 at 11:08:10AM -0700, Jeremy Allison wrote:
> > The right place is clearly Samba.  I can't think of any other program
> > or filesystem protocol where writing a 1 byte write at 128k strides
> > would be used to signal a desire to do preallocation.  In fact, it's
> > hard to think of a worse way of doing things.
> 
> In fact they don't need to do this - there's an explicit CIFS
> set file allocation call to pre-allocate size they could use.
> 
> There's a specific Samba VFS module that has XFS specific calls
> to do this - vfs_prealloc. - but this won't work on ext3.

Jeremy,

	FYI, we are currently closing on a new system call so that
glibc's fallocate() will be able to call into the appropriate
per-filesystem routines in a portable way, since ext4 will have
persistent preallocation support.

	I think we mostly have consensus on a calling convention which
all of the architectures (s390, power, arm, ia64, etc.); of course
then we will need to get glibc to support the new system call.

						- Ted

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