Re: [PATCH v7 2/2] xfs: avoid transaction reservation recursion

[Matthew Wilcox <willy@xxxxxxxxxxxxx>]

On Thu, Aug 27, 2020 at 09:34:44AM +0800, Yafang Shao wrote:
> @@ -1500,9 +1500,9 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
>  
>  	/*
>  	 * Given that we do not allow direct reclaim to call us, we should
> -	 * never be called in a recursive filesystem reclaim context.
> +	 * never be called while in a filesystem transaction.
>  	 */
> -	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS))
> +	if (WARN_ON_ONCE(wbc->fstrans_recursion))
>  		goto redirty;

Erm, Dave said:

> I think we should just remove
> the check completely from iomap_writepage() and move it up into
> xfs_vm_writepage() and xfs_vm_writepages().

ie everywhere you set this new bit, just check current->journal_info.