cifs: use compounding for open and first query-dir for readdir()

Combine the initial SMB2_Open and the first SMB2_Query_Directory in a compound.
This shaves one round-trip of each directory listing, changing it from 4 to 3
for small directories.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

fs/cifs/cifsproto.h

@@ -596,6 +596,9 @@ bool is_ses_using_iface(struct cifs_ses *ses, struct cifs_server_iface *iface);
 
 void extract_unc_hostname(const char *unc, const char **h, size_t *len);
 int copy_path_name(char *dst, const char *src);
+int smb2_parse_query_directory(struct cifs_tcon *tcon, struct kvec *rsp_iov,
+			       int resp_buftype,
+			       struct cifs_search_info *srch_inf);
 
 #ifdef CONFIG_CIFS_DFS_UPCALL
 static inline int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,

fs/cifs/smb2ops.c

@@ -2053,14 +2053,33 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 		     struct cifs_search_info *srch_inf)
 {
 	__le16 *utf16_path;
-	int rc;
-	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
+	struct smb_rqst rqst[2];
+	struct kvec rsp_iov[2];
+	int resp_buftype[2];
+	struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
+	struct kvec qd_iov[SMB2_QUERY_DIRECTORY_IOV_SIZE];
+	int rc, flags = 0;
+	u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 	struct cifs_open_parms oparms;
+	struct smb2_query_directory_rsp *qd_rsp = NULL;
+	struct smb2_create_rsp *op_rsp = NULL;
 
 	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 	if (!utf16_path)
 		return -ENOMEM;
 
+	if (smb3_encryption_required(tcon))
+		flags |= CIFS_TRANSFORM_REQ;
+
+	memset(rqst, 0, sizeof(rqst));
+	resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER;
+	memset(rsp_iov, 0, sizeof(rsp_iov));
+
+	/* Open */
+	memset(&open_iov, 0, sizeof(open_iov));
+	rqst[0].rq_iov = open_iov;
+	rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;
+
 	oparms.tcon = tcon;
 	oparms.desired_access = FILE_READ_ATTRIBUTES | FILE_READ_DATA;
 	oparms.disposition = FILE_OPEN;
@@ -2071,22 +2090,75 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL);
-	kfree(utf16_path);
-	if (rc) {
-		cifs_dbg(FYI, "open dir failed rc=%d\n", rc);
-		return rc;
-	}
+	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	if (rc)
+		goto qdf_free;
+	smb2_set_next_command(tcon, &rqst[0]);
 
+	/* Query directory */
 	srch_inf->entries_in_buffer = 0;
 	srch_inf->index_of_last_entry = 2;
 
-	rc = SMB2_query_directory(xid, tcon, fid->persistent_fid,
-				  fid->volatile_fid, 0, srch_inf);
-	if (rc) {
-		cifs_dbg(FYI, "query directory failed rc=%d\n", rc);
+	memset(&qd_iov, 0, sizeof(qd_iov));
+	rqst[1].rq_iov = qd_iov;
+	rqst[1].rq_nvec = SMB2_QUERY_DIRECTORY_IOV_SIZE;
+
+	rc = SMB2_query_directory_init(xid, tcon, &rqst[1],
+				       COMPOUND_FID, COMPOUND_FID,
+				       0, srch_inf->info_level);
+	if (rc)
+		goto qdf_free;
+
+	smb2_set_related(&rqst[1]);
+
+	rc = compound_send_recv(xid, tcon->ses, flags, 2, rqst,
+				resp_buftype, rsp_iov);
+
+	/* If the open failed there is nothing to do */
+	op_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
+	if (op_rsp == NULL || op_rsp->sync_hdr.Status != STATUS_SUCCESS) {
+		cifs_dbg(FYI, "query_dir_first: open failed rc=%d\n", rc);
+		goto qdf_free;
+	}
+	fid->persistent_fid = op_rsp->PersistentFileId;
+	fid->volatile_fid = op_rsp->VolatileFileId;
+
+	/* Anything else than ENODATA means a genuine error */
+	if (rc && rc != -ENODATA) {
 		SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
+		cifs_dbg(FYI, "query_dir_first: query directory failed rc=%d\n", rc);
+		trace_smb3_query_dir_err(xid, fid->persistent_fid,
+					 tcon->tid, tcon->ses->Suid, 0, 0, rc);
+		goto qdf_free;
 	}
+
+	qd_rsp = (struct smb2_query_directory_rsp *)rsp_iov[1].iov_base;
+	if (qd_rsp->sync_hdr.Status == STATUS_NO_MORE_FILES) {
+		trace_smb3_query_dir_done(xid, fid->persistent_fid,
+					  tcon->tid, tcon->ses->Suid, 0, 0);
+		srch_inf->endOfSearch = true;
+		rc = 0;
+		goto qdf_free;
+	}
+
+	rc = smb2_parse_query_directory(tcon, &rsp_iov[1], resp_buftype[1],
+					srch_inf);
+	if (rc) {
+		trace_smb3_query_dir_err(xid, fid->persistent_fid, tcon->tid,
+			tcon->ses->Suid, 0, 0, rc);
+		goto qdf_free;
+	}
+	resp_buftype[1] = CIFS_NO_BUFFER;
+
+	trace_smb3_query_dir_done(xid, fid->persistent_fid, tcon->tid,
+			tcon->ses->Suid, 0, srch_inf->entries_in_buffer);
+
+ qdf_free:
+	kfree(utf16_path);
+	SMB2_open_free(&rqst[0]);
+	SMB2_query_directory_free(&rqst[1]);
+	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
+	free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
 	return rc;
 }