NFSv4: Revert commit 5f83d86cf531d ("NFSv4.x: Fix wraparound issues..")

The correct behaviour for NFSv4 sequence IDs is to wrap around
to the value 0 after 0xffffffff.
See https://tools.ietf.org/html/rfc5661#section-2.10.6.1

Fixes: 5f83d86cf531d ("NFSv4.x: Fix wraparound issues when validing...")
Cc: stable@vger.kernel.org # 4.6+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 3a49bb19ef07..ee81031cab29 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -428,11 +428,8 @@ validate_seqid(const struct nfs4_slot_table *tbl, const struct nfs4_slot *slot,
                 return htonl(NFS4ERR_SEQ_FALSE_RETRY);
         }
 
-        /* Wraparound */
-        if (unlikely(slot->seq_nr == 0xFFFFFFFFU)) {
-                if (args->csa_sequenceid == 1)
-                        return htonl(NFS4_OK);
-        } else if (likely(args->csa_sequenceid == slot->seq_nr + 1))
+        /* Note: wraparound relies on seq_nr being of type u32 */
+        if (likely(args->csa_sequenceid == slot->seq_nr + 1))
                 return htonl(NFS4_OK);
 
         /* Misordered request */