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Date:   Fri, 25 Mar 2022 00:33:58 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     "Yuezhang.Mo@sony.com" <Yuezhang.Mo@sony.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Namjae Jeon <linkinjeon@kernel.org>,
        "sj1557.seo@samsung.com" <sj1557.seo@samsung.com>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Andy.Wu@sony.com" <Andy.Wu@sony.com>,
        "Wataru.Aoyama@sony.com" <Wataru.Aoyama@sony.com>
Subject: Re: [PATCH] exfat: reduce block requests when zeroing a cluster
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On Fri, Mar 25, 2022 at 07:22:54AM +0000, Yuezhang.Mo@sony.com wrote:
> Hi Christoph Hellwig,
> 
> Thank you for your comment.
> 
> > On Fri, Mar 25, 2022 at 03:00:55AM +0000, Yuezhang.Mo@sony.com wrote:
> > > +#include <linux/blk_types.h>
> > 
> > blk_types.h is not a header for public use.  What do you want it for?
> 
> +	struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
> 
> The type of 'sb->s_bdev' is 'struct block_device'.
> I want to include the definition of 'struct block_device'('struct block_device' is defined in <linux/blk_types.h>).

Oh, I missed that.  We really should not derefrence bd_inode in file
systems.  So maybe we need to add a sync_blockdev_range abstraction if
we want to support this use case.