diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 3a507c42c1ca..52dbd17e401e 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -187,7 +187,11 @@ static loff_t nfs42_remap_file_range(struct file *src_file, loff_t src_off,
 	bool same_inode = false;
 	int ret;
 
-	if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
+	/* NFS does not support deduplication. */
+	if (remap_flags & REMAP_FILE_DEDUP)
+		return -EOPNOTSUPP;
+
+	if (remap_flags & ~REMAP_FILE_ADVISORY)
 		return -EINVAL;
 
 	/* check alignment w.r.t. clone_blksize */