Date: Thu, 15 Apr 2010 15:34:31 +0200
From: Jan Kara <jack@suse.cz>
To: Christoph Hellwig <hch@lst.de>
Cc: Anton Blanchard <anton@samba.org>, Jan Kara <jack@suse.cz>,
       Alexander Viro <viro@zeniv.linux.org.uk>,
       Jens Axboe <jens.axboe@oracle.com>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix regression in O_DIRECT|O_SYNC writes to block
 devices
Message-ID: <20100415133431.GD3561@quack.suse.cz>
References: <20100415044039.GJ11751@kryten>
 <20100415104224.GA27482@lst.de>
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On Thu 15-04-10 12:42:24, Christoph Hellwig wrote:
> On Thu, Apr 15, 2010 at 02:40:39PM +1000, Anton Blanchard wrote:
> >  int blkdev_fsync(struct file *filp, struct dentry *dentry, int datasync)
> >  {
> > -	struct block_device *bdev = I_BDEV(filp->f_mapping->host);
> > +	struct inode *bd_inode = filp->f_mapping->host;
> > +	struct block_device *bdev = I_BDEV(bd_inode);
> >  	int error;
> >  
> > +	mutex_unlock(&bd_inode->i_mutex);
> > +
> >  	error = sync_blockdev(bdev);
> 
> Actually you can just drop this call entirely.  sync_blockdev is an
> overcomplicated alias for filemap_write_and_wait on the  block device
> inode, which is exactl what we did just before calling into ->fsync
> 
> It might be worth to still drop i_mutex for the cache flush, though.
  Yeah, that's a good point... Anton, just remove sync_blockdev() from
blkdev_fsync completely please.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR
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