On Thu, Apr 21, 2022 at 1:37 AM Xiubo Li <xiubli@xxxxxxxxxx> wrote:
>
> Since we have held the Fr capibility it's safe to skip reading from
> Rados if the ki_pos is larger than or euqals to the file size.
I'm not sure this is correct, based on the patch description. If
you're in a mixed mode where there are writers and readers, they can
all have Frw and extend the file size by issuing rados writes up to
the max_size without updating each other. The client needs to have Fs
before it can rely on knowing the file size, so we should check that
before skipping a read, right?
-Greg
>
> Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
> ---
> fs/ceph/file.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 6c9e837aa1d3..330e42b3afec 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -1614,7 +1614,9 @@ static ssize_t ceph_read_iter(struct kiocb *iocb, struct iov_iter *to)
> return ret;
> }
>
> - if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
> + if (unlikely(iocb->ki_pos >= i_size_read(inode))) {
> + ret = 0;
> + } else if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
> (iocb->ki_flags & IOCB_DIRECT) ||
> (fi->flags & CEPH_F_SYNC)) {
>
> --
> 2.36.0.rc1
>
