On Thu, 2022-08-25 at 10:41 +0100, Luís Henriques wrote:
> On Thu, Aug 25, 2022 at 10:32:56AM +0200, Ilya Dryomov wrote:
> > On Wed, Aug 24, 2022 at 10:53 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> > >
> > > ceph_sync_write has assumed that a zero result in req->r_result means
> > > success. Testing with a recent cluster however shows the OSD returning
> > > a non-zero length written here. I'm not sure whether and when this
> > > changed, but fix the code to accept either result.
> > >
> > > Assume a negative result means error, and anything else is a success. If
> > > we're given a short length, then return a short write.
> > >
> > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > > ---
> > > fs/ceph/file.c | 10 +++++++++-
> > > 1 file changed, 9 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> > > index 86265713a743..c0b2c8968be9 100644
> > > --- a/fs/ceph/file.c
> > > +++ b/fs/ceph/file.c
> > > @@ -1632,11 +1632,19 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
> > > req->r_end_latency, len, ret);
> > > out:
> > > ceph_osdc_put_request(req);
> > > - if (ret != 0) {
> > > + if (ret < 0) {
> > > ceph_set_error_write(ci);
> > > break;
> > > }
> > >
> > > + /*
> > > + * FIXME: it's unclear whether all OSD versions return the
> > > + * length written on a write. For now, assume that a 0 return
> > > + * means that everything got written.
> > > + */
> > > + if (ret && ret < len)
> > > + len = ret;
> > > +
> > > ceph_clear_error_write(ci);
> > > pos += len;
> > > written += len;
> > > --
> > > 2.37.2
> > >
> >
> > Hi Jeff,
> >
> > AFAIK OSDs aren't allowed to return any kind of length on a write
> > and there is no such thing as a short write. This definitely needs
> > deeper investigation.
> >
> > What is the cluster version you are testing against?
>
> OK, I'm only seeing 'ret' being set to the write length only when enabling
> encryption (i.e. with test_dummy_encryption mount option). So, maybe the
> right fix is something like:
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 16dcade66923..5119d87d61fb 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -1889,6 +1889,7 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
> ceph_release_page_vector(pages, num_pages);
> break;
> }
> + ret = 0;
> }
>
> req = ceph_osdc_new_request(osdc, &ci->i_layout,
>
No, actually. I think the original patch I sent is just wrong. There was
another bug (another missing ceph_osdc_wait_request) in the fscrypt
stack that was causing r_result to not appear to be zero.
I've fixed this in the ceph-fscrypt branch in my tree and it seems to be
working. I'll plan do a re-send of the fscrypt patches that are not yet
in the testing branch today.
Thanks!
--
Jeff Layton <jlayton@xxxxxxxxxx>
