Re: [PATCH v4 7/7] iov_iter, block: Make bio structs pin pages rather than ref'ing if appropriate

[David Howells]

Jan Kara <jack@xxxxxxx> wrote:

> ... So filesystems really need DIO reads to use FOLL_PIN instead of FOLL_GET
> and consequently we need to pass information to bio completion function how
> page references should be dropped.

That information would be available in the bio struct with this patch if
necessary, though transcribed into a combination of BIO_* flags instead off
FOLL_* flags.

I wonder if there's the possibility of the filesystem that generated the bio
nicking the pages out of the bio and putting them itself.

David