On Mon, Jul 31, 2023 at 04:27:30PM -0400, Jeff Layton wrote: > I noticed that xfstests generic/001 was failing against linux-next nfsd. Only on NFSv4.2 mounts, I presume? > The client would request a OPEN4_SHARE_ACCESS_WRITE open, and the server > would hand out a write delegation. The client would then try to use that > write delegation as the source stateid in a COPY or CLONE operation, and > the server would respond with NFS4ERR_STALE. > > The problem is that the struct file associated with the delegation does > not necessarily have read permissions. It's handing out a write > delegation on what is effectively an O_WRONLY open. RFC 8881 states: > > "An OPEN_DELEGATE_WRITE delegation allows the client to handle, on its > own, all opens." > > Given that the client didn't request any read permissions, and that nfsd > didn't check for any, it seems wrong to give out a write delegation. A client is, in fact, permitted to use a write delegation stateid in an otw READ operation. So, this makes sense to me. > Don't hand out a delegation if the client didn't request > OPEN4_SHARE_ACCESS_BOTH. > > This fixes xfstest generic/001. > > Closes: https://bugzilla.linux-nfs.org/show_bug.cgi?id=412 > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> I'm thinking this should be squashed into commit 68a593f24a35 ("NFSD: Enable write delegation support"). > --- > fs/nfsd/nfs4state.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index ef7118ebee00..9f1c90afed72 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -5462,6 +5462,8 @@ nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp, > return ERR_PTR(-EAGAIN); > > if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) { > + if (!(open->op_share_access & NFS4_SHARE_ACCESS_READ)) > + return ERR_PTR(-EBADF); return ERR_PTR(-EAGAIN); might be more consistent with the other failure returns in this function. > nf = find_writeable_file(fp); > dl_type = NFS4_OPEN_DELEGATE_WRITE; > } else { > > --- > base-commit: ec89391563792edd11d138a853901bce76d11f44 > change-id: 20230731-wdeleg-bbdb6b25a3c6 > > Best regards, > -- > Jeff Layton <jlayton@xxxxxxxxxx> > -- Chuck Lever
