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Date:   Mon, 23 Jan 2023 22:32:06 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc:     Keith Busch <kbusch@kernel.org>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>
Subject: Re: What would happen if the block device driver/firmware found some
 block of a bio is corrupted?
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On Tue, Jan 24, 2023 at 01:38:41PM +0800, Qu Wenruo wrote:
> The retry for file read is indeed triggered inside VFS, not fs/block/dm
> layer itself.

Well, it's really MM code.  If ->readahead fails, we eventually fall
back to a single-page ->radpage.  That might still be more than one
sector in some cases, but at least nicely narrows down the range.