NFSv4/pnfs: The layout barrier indicate a minimal value for the seqid

[ Upstream commit d6236a9 ]

The intention of the layout barrier is to ensure that we do not update
the layout to match an older value than the current expectation. Fix the
test in pnfs_layout_stateid_blocked() to reflect that it is legal for
the seqid of the stateid to match that of the barrier.

Fixes: aa95edf ("NFSv4/pnfs: Fix the layout barrier update")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/nfs/pnfs.c

@@ -1004,7 +1004,7 @@ pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
 {
 	u32 seqid = be32_to_cpu(stateid->seqid);
 
-	return !pnfs_seqid_is_newer(seqid, lo->plh_barrier) && lo->plh_barrier;
+	return lo->plh_barrier && pnfs_seqid_is_newer(lo->plh_barrier, seqid);
 }
 
 /* lget is set to 1 if called from inside send_layoutget call chain */