cifs: add a CIFSSMBUnixQFileInfo function

...to allow us to get unix attrs via filehandle.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsproto.h

@@ -154,6 +154,8 @@ extern int SMBQueryInformation(const int xid, struct cifsTconInfo *tcon,
 			FILE_ALL_INFO *findData,
 			const struct nls_table *nls_codepage, int remap);
 
+extern int CIFSSMBUnixQFileInfo(const int xid, struct cifsTconInfo *tcon,
+			u16 netfid, FILE_UNIX_BASIC_INFO *pFindData);
 extern int CIFSSMBUnixQPathInfo(const int xid,
 			struct cifsTconInfo *tcon,
 			const unsigned char *searchName,

fs/cifs/cifssmb.c

@@ -3398,6 +3398,75 @@ CIFSSMBQPathInfo(const int xid, struct cifsTconInfo *tcon,
 	return rc;
 }
 
+int
+CIFSSMBUnixQFileInfo(const int xid, struct cifsTconInfo *tcon,
+		 u16 netfid, FILE_UNIX_BASIC_INFO *pFindData)
+{
+	struct smb_t2_qfi_req *pSMB = NULL;
+	struct smb_t2_qfi_rsp *pSMBr = NULL;
+	int rc = 0;
+	int bytes_returned;
+	__u16 params, byte_count;
+
+UnixQFileInfoRetry:
+	rc = smb_init(SMB_COM_TRANSACTION2, 15, tcon, (void **) &pSMB,
+		      (void **) &pSMBr);
+	if (rc)
+		return rc;
+
+	params = 2 /* level */ + 2 /* fid */;
+	pSMB->t2.TotalDataCount = 0;
+	pSMB->t2.MaxParameterCount = cpu_to_le16(4);
+	/* BB find exact max data count below from sess structure BB */
+	pSMB->t2.MaxDataCount = cpu_to_le16(CIFSMaxBufSize);
+	pSMB->t2.MaxSetupCount = 0;
+	pSMB->t2.Reserved = 0;
+	pSMB->t2.Flags = 0;
+	pSMB->t2.Timeout = 0;
+	pSMB->t2.Reserved2 = 0;
+	pSMB->t2.ParameterOffset = cpu_to_le16(offsetof(struct smb_t2_qfi_req,
+					       Fid) - 4);
+	pSMB->t2.DataCount = 0;
+	pSMB->t2.DataOffset = 0;
+	pSMB->t2.SetupCount = 1;
+	pSMB->t2.Reserved3 = 0;
+	pSMB->t2.SubCommand = cpu_to_le16(TRANS2_QUERY_FILE_INFORMATION);
+	byte_count = params + 1 /* pad */ ;
+	pSMB->t2.TotalParameterCount = cpu_to_le16(params);
+	pSMB->t2.ParameterCount = pSMB->t2.TotalParameterCount;
+	pSMB->InformationLevel = cpu_to_le16(SMB_QUERY_FILE_UNIX_BASIC);
+	pSMB->Pad = 0;
+	pSMB->Fid = netfid;
+	pSMB->hdr.smb_buf_length += byte_count;
+
+	rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB,
+			 (struct smb_hdr *) pSMBr, &bytes_returned, 0);
+	if (rc) {
+		cFYI(1, ("Send error in QPathInfo = %d", rc));
+	} else {		/* decode response */
+		rc = validate_t2((struct smb_t2_rsp *)pSMBr);
+
+		if (rc || (pSMBr->ByteCount < sizeof(FILE_UNIX_BASIC_INFO))) {
+			cERROR(1, ("Malformed FILE_UNIX_BASIC_INFO response.\n"
+				   "Unix Extensions can be disabled on mount "
+				   "by specifying the nosfu mount option."));
+			rc = -EIO;	/* bad smb */
+		} else {
+			__u16 data_offset = le16_to_cpu(pSMBr->t2.DataOffset);
+			memcpy((char *) pFindData,
+			       (char *) &pSMBr->hdr.Protocol +
+			       data_offset,
+			       sizeof(FILE_UNIX_BASIC_INFO));
+		}
+	}
+
+	cifs_buf_release(pSMB);
+	if (rc == -EAGAIN)
+		goto UnixQFileInfoRetry;
+
+	return rc;
+}
+
 int
 CIFSSMBUnixQPathInfo(const int xid, struct cifsTconInfo *tcon,
 		     const unsigned char *searchName,