[Devel] [PATCH] fuse kio: Add comment about why we need to wait pending read requests

[Pavel Butsykin]

On 23.10.2018 13:01, Kirill Tkhai wrote:
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> ---
>   fs/fuse/kio/pcs/pcs_fuse_kdirect.c |    7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
> index 3940d6c255ba..9b45fcbf8941 100644
> --- a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
> +++ b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
> @@ -1081,7 +1081,12 @@ static void pcs_kio_setattr_handle(struct fuse_inode *fi, struct fuse_req *req)
>   	r->end = req->end;
>   	if (di->size.op == PCS_SIZE_SHRINK) {
>   		BUG_ON(!mutex_is_locked(&req->io_inode->i_mutex));
> -		/* wait for aio reads in flight */
> +		/*
> +		 * Wait for already submitted aio reads. Further reads
> +		 * (including already queued to bg_queue) will be stopped
> +		 * by wait_shrink(), and they will be processed from
> +		 * _pcs_shrink_end().
> +		 */

Why do we have to wait already submitted aio reads ?

>   		inode_dio_wait(req->io_inode);
>   		/*
>   		 * Writebackcache was flushed already so it is safe to
>