smb3_fs_context_dup
rc = smb3_fs_context_dup(cifs_sb->ctx, old_ctx);
rc = smb3_fs_context_dup(old_ctx, cifs_sb->ctx);
rc = smb3_fs_context_dup(new_ctx, ctx);
int smb3_fs_context_dup(struct smb3_fs_context *new_ctx,
rc = smb3_fs_context_dup(ctx, &tmp);