On Wed, Jan 18, 2023 at 10:43:28AM +0100, Christoph Hellwig wrote:
> filemap_get_folio can return NULL, skip those cases.
Hmm, I'm not sure that's true. We have one place that calls
extent_range_redirty_for_io(), and it previously calls
extent_range_clear_dirty_for_io() which has an explicit
BUG_ON(!page); /* Pages should be in the extent_io_tree */
so I'm going to say this one can't happen either. I haven't delved far
enough into btrfs to figure out why it can't happen.
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/btrfs/extent_io.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index d55e4531ffd212..a54d2cf74ba020 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -230,6 +230,8 @@ void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
>
> while (index <= end_index) {
> folio = filemap_get_folio(mapping, index);
> + if (!folio)
> + continue;
> filemap_dirty_folio(mapping, folio);
> folio_account_redirty(folio);
> index += folio_nr_pages(folio);
> --
> 2.39.0
>
