cifs: change smb2_query_info_compound to use a cached fid, if available

This will reduce the number of Open/Close we send on the wire and replace
a Open/GetInfo/Close compound with just a simple GetInfo request
IF we have a cached handle for the object.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2ops.c

@@ -2659,6 +2659,7 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	struct cifs_fid fid;
 	int rc;
 	__le16 *utf16_path;
+	struct cached_fid *cfid = NULL;
 
 	if (!path)
 		path = "";
@@ -2673,6 +2674,8 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	resp_buftype[0] = resp_buftype[1] = resp_buftype[2] = CIFS_NO_BUFFER;
 	memset(rsp_iov, 0, sizeof(rsp_iov));
 
+	rc = open_cached_dir(xid, tcon, path, cifs_sb, &cfid);
+
 	memset(&open_iov, 0, sizeof(open_iov));
 	rqst[0].rq_iov = open_iov;
 	rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;
@@ -2694,15 +2697,29 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = qi_iov;
 	rqst[1].rq_nvec = 1;
 
-	rc = SMB2_query_info_init(tcon, server,
-				  &rqst[1], COMPOUND_FID, COMPOUND_FID,
-				  class, type, 0,
-				  output_len, 0,
-				  NULL);
+	if (cfid) {
+		rc = SMB2_query_info_init(tcon, server,
+					  &rqst[1],
+					  cfid->fid->persistent_fid,
+					  cfid->fid->volatile_fid,
+					  class, type, 0,
+					  output_len, 0,
+					  NULL);
+	} else {
+		rc = SMB2_query_info_init(tcon, server,
+					  &rqst[1],
+					  COMPOUND_FID,
+					  COMPOUND_FID,
+					  class, type, 0,
+					  output_len, 0,
+					  NULL);
+	}
 	if (rc)
 		goto qic_exit;
-	smb2_set_next_command(tcon, &rqst[1]);
-	smb2_set_related(&rqst[1]);
+	if (!cfid) {
+		smb2_set_next_command(tcon, &rqst[1]);
+		smb2_set_related(&rqst[1]);
+	}
 
 	memset(&close_iov, 0, sizeof(close_iov));
 	rqst[2].rq_iov = close_iov;
@@ -2714,9 +2731,15 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 		goto qic_exit;
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, ses, server,
-				flags, 3, rqst,
-				resp_buftype, rsp_iov);
+	if (cfid) {
+		rc = compound_send_recv(xid, ses, server,
+					flags, 1, &rqst[1],
+					&resp_buftype[1], &rsp_iov[1]);
+	} else {
+		rc = compound_send_recv(xid, ses, server,
+					flags, 3, rqst,
+					resp_buftype, rsp_iov);
+	}
 	if (rc) {
 		free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
 		if (rc == -EREMCHG) {
@@ -2736,6 +2759,8 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	SMB2_close_free(&rqst[2]);
 	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
 	free_rsp_buf(resp_buftype[2], rsp_iov[2].iov_base);
+	if (cfid)
+		close_cached_dir(cfid);
 	return rc;
 }