From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 0/4][RFC] remove duplicated check from ext4, xfs, btrfs,
 and ocfs2
Date: Tue, 20 Nov 2012 05:14:53 -0500
Message-ID: <20121120101452.GA692@infradead.org>
References: <1353403785-3489-1-git-send-email-wenqing.lz@taobao.com>
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Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	xfs@oss.sgi.com, linux-btrfs@vger.kernel.org,
	ocfs2-devel@oss.oracle.com, yan@linux.vnet.ibm.com,
	Zheng Liu <wenqing.lz@taobao.com>
To: Zheng Liu <gnehzuil.liu@gmail.com>
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On Tue, Nov 20, 2012 at 05:29:41PM +0800, Zheng Liu wrote:
> Hi all,
> 
> This patch series tries to remove a sanity check in fallocate from specific
> filesystems because vfs has already checked it.
> 
> I am not very familiar with why we need to do this duplicated check.  Please let
> me know if I miss something.

Each filesystem driver checks to see if a flag that it doesn't support
gets passed down.  This was done with the intention that we can add new
flags to the VFS without having to update every filesystem.