nfsd4: ignore WANT bits in open downgrade

We don't use WANT bits yet--and sending them can probably trigger a
BUG() further down.

Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 683885b18ceb..a39a542d8be5 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3574,6 +3574,8 @@ nfsd4_open_downgrade(struct svc_rqst *rqstp,
         if (!access_valid(od->od_share_access, cstate->minorversion)
                         || !deny_valid(od->od_share_deny))
                 return nfserr_inval;
+        /* We don't yet support WANT bits: */
+        od->od_share_access &= NFS4_SHARE_ACCESS_MASK;
 
         nfs4_lock_state();
         status = nfs4_preprocess_confirmed_seqid_op(cstate, od->od_seqid,