[CIFS] Allow SMBWrite2 to work to older servers

Signed-off-by: Steve French (sfrench@us.ibm.com)

fs/cifs/cifssmb.c

@@ -1139,11 +1139,15 @@ CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon,
 {
 	int rc = -EACCES;
 	WRITE_REQ *pSMB = NULL;
-	int bytes_returned;
+	int bytes_returned, wct;
 	int smb_hdr_len;
 
 	cFYI(1,("write2 at %lld %d bytes",offset,count)); /* BB removeme BB */
-	rc = small_smb_init(SMB_COM_WRITE_ANDX, 14, tcon, (void **) &pSMB);
+	if(tcon->ses->capabilities & CAP_LARGE_FILES)
+		wct = 14;
+	else
+		wct = 12;
+	rc = small_smb_init(SMB_COM_WRITE_ANDX, wct, tcon, (void **) &pSMB);
 	if (rc)
 		return rc;
 	/* tcon and ses pointer are checked in smb_init */
@@ -1153,7 +1157,10 @@ CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon,
 	pSMB->AndXCommand = 0xFF;	/* none */
 	pSMB->Fid = netfid;
 	pSMB->OffsetLow = cpu_to_le32(offset & 0xFFFFFFFF);
-	pSMB->OffsetHigh = cpu_to_le32(offset >> 32);
+	if(wct == 14)
+		pSMB->OffsetHigh = cpu_to_le32(offset >> 32);
+	else if((offset >> 32) > 0) /* can not handle this big offset for old */
+		return -EIO;
 	pSMB->Reserved = 0xFFFFFFFF;
 	pSMB->WriteMode = 0;
 	pSMB->Remaining = 0;
@@ -1164,9 +1171,17 @@ CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon,
 	pSMB->DataLengthLow = cpu_to_le16(count & 0xFFFF);
 	pSMB->DataLengthHigh = cpu_to_le16(count >> 16);
 	smb_hdr_len = pSMB->hdr.smb_buf_length + 1; /* hdr + 1 byte pad */
-	pSMB->hdr.smb_buf_length += count+1;
-	pSMB->ByteCount = cpu_to_le16(count + 1);
-
+	if(wct == 14)
+		pSMB->hdr.smb_buf_length += count+1;
+	else /* wct == 12 */
+		pSMB->hdr.smb_buf_length += count+5; /* smb data starts later */ 
+	if(wct == 14)
+		pSMB->ByteCount = cpu_to_le16(count + 1);
+	else /* wct == 12 */ /* bigger pad, smaller smb hdr, keep offset ok */ {
+		struct smb_com_writex_req * pSMBW =
+				(struct smb_com_writex_req *)pSMB;
+		pSMBW->ByteCount = cpu_to_le16(count + 5);
+	}
 	iov[0].iov_base = pSMB;
 	iov[0].iov_len = smb_hdr_len + 4;
 
@@ -1174,7 +1189,7 @@ CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon,
 			  long_op);
 	cifs_stats_inc(&tcon->num_writes);
 	if (rc) {
-		cFYI(1, ("Send error in write = %d", rc));
+		cFYI(1, ("Send error Write2 = %d", rc));
 		*nbytes = 0;
 	} else {
 		WRITE_RSP * pSMBr = (WRITE_RSP *)pSMB;