Re: [PATCH v2 6/9] mm: set mapping error when launder_pages fails

[Trond Myklebust]

On Wed, 2017-03-08 at 11:29 -0500, Jeff Layton wrote:
> If launder_page fails, then we hit a problem writing back some inode
> data. Ensure that we communicate that fact in a subsequent fsync
> since
> another task could still have it open for write.
> 
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> Âmm/truncate.c | 6 +++++-
> Â1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/truncate.c b/mm/truncate.c
> index 6263affdef88..29ae420a5bf9 100644
> --- a/mm/truncate.c
> +++ b/mm/truncate.c
> @@ -594,11 +594,15 @@ invalidate_complete_page2(struct address_space
> *mapping, struct page *page)
> Â
> Âstatic int do_launder_page(struct address_space *mapping, struct
> page *page)
> Â{
> +	int ret;
> +
> Â	if (!PageDirty(page))
> Â		return 0;
> Â	if (page->mapping != mapping || mapping->a_ops->launder_page 
> == NULL)
> Â		return 0;
> -	return mapping->a_ops->launder_page(page);
> +	ret = mapping->a_ops->launder_page(page);
> +	mapping_set_error(mapping, ret);
> +	return ret;
> Â}
> Â
> Â/**

No. At that layer, you don't know that this is a page error. In the NFS
case, it could, for instance, just as well be a fatal signal.

-- 
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@xxxxxxxxxxxxxxx