Re: [PATCH v2] fs: Fix page cache inconsistency when mixing buffered and AIO DIO for bdev

[Dave Chinner <david@fromorbit.com>]

On Sat, May 07, 2022 at 12:10:33PM +0800, Liang Chen wrote:
> From: Liang Chen <liangchen.linux@gmail.com>
> 
> As pointed out in commit 332391a, mixing buffered reads and asynchronous
> direct writes risks ending up with a situation where stale data is left
> in page cache while new data is already written to disk. The same problem
> hits block dev fs too. A similar approach needs to be taken here.
> 
> Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
> ---
> V2: declare blkdev_sb_init_dio_done_wq static
> ---
>  block/fops.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 87 insertions(+)

Rather than copying functionality from the two other generic DIO
paths (which we really want to get down to 1!) into this cut down,
less functional DIO path, shouldn't we be spending the effort to
convert the blkdev device to use one of the other generic DIO paths
that already solves this problem and likely gets a lot more test
coverage?

Cheers,

Dave.

-- 
Dave Chinner
david@fromorbit.com