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Date: Fri, 20 May 2011 09:29:10 +1000
From: Dave Chinner <david@fromorbit.com>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Jan Kara <jack@suse.cz>,
        Christoph Hellwig <hch@infradead.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 14/18] writeback: make writeback_control.nr_to_write
 straight
Message-ID: <20110519232910.GK32466@dastard>
References: <20110519214530.939830917@intel.com>
 <20110519214746.038765568@intel.com>
 <20110519220643.GA27247@localhost>
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On Fri, May 20, 2011 at 06:06:44AM +0800, Wu Fengguang wrote:
> :                 writeback_single_inode(inode, wb, &wbc);
> :                 work->nr_pages -= write_chunk - wbc.nr_to_write;
> :                 wrote += write_chunk - wbc.nr_to_write;
> :                 if (wbc.pages_skipped) {
> :                         /*
> :                          * writeback is not making progress due to locked
> :                          * buffers.  Skip this inode for now.
> :                          */
> :                         redirty_tail(inode, wb);
> : -               }
> : +               } else if (!(inode->i_state & I_DIRTY))
> : +                       wrote++;
> 
> It looks a bit more clean to do
> 
> :                 wrote += write_chunk - wbc.nr_to_write;
> : +               if (!(inode->i_state & I_DIRTY))
> : +                       wrote++;
> :                 if (wbc.pages_skipped) {
> :                         /*
> :                          * writeback is not making progress due to locked
> :                          * buffers.  Skip this inode for now.
> :                          */
> :                         redirty_tail(inode, wb);
> :                 }

But it's still in the wrong place - such post-write inode dirty
processing is supposed to be isolated to writeback_single_inode().
Spreading it across multiple locations is not, IMO, the nicest thing
to do...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com