Merge pull request #22 from carmark/scsi_flags

support more scsi commands

.travis.yml

@@ -43,6 +43,11 @@ script:
    - ./test-tool/iscsi-test-cu -d -f --test=SCSI.Write10.Simple iscsi://127.0.0.1:3260/${TARGET}/0
    - ./test-tool/iscsi-test-cu -d -f --test=SCSI.Read16.Simple iscsi://127.0.0.1:3260/${TARGET}/0
    - ./test-tool/iscsi-test-cu -d -f --test=SCSI.Write16.Simple iscsi://127.0.0.1:3260/${TARGET}/0
+   - ./test-tool/iscsi-test-cu -d -f --test=SCSI.Read32.Simple iscsi://127.0.0.1:3260/${TARGET}/0
+   - ./test-tool/iscsi-test-cu -d -f --test=SCSI.Write32.Simple iscsi://127.0.0.1:3260/${TARGET}/0
+   - ./test-tool/iscsi-test-cu -d -f --test=SCSI.WriteVerify10.Simple iscsi://127.0.0.1:3260/${TARGET}/0
+   - ./test-tool/iscsi-test-cu -d -f --test=SCSI.WriteVerify16.Simple iscsi://127.0.0.1:3260/${TARGET}/0
+   - ./test-tool/iscsi-test-cu -d -f --test=SCSI.WriteVerify32.Simple iscsi://127.0.0.1:3260/${TARGET}/0
    - ./utils/iscsi-ls -s iscsi://127.0.0.1:3260/${TARGET}
    - ./utils/iscsi-inq iscsi://127.0.0.1:3260/${TARGET}/0
    - ./utils/iscsi-readcapacity16 iscsi://127.0.0.1:3260/${TARGET}/0

README.md

@@ -65,8 +65,6 @@ You can test this with [open-iscsi](http://www.open-iscsi.com/) or [libiscsi](ht
 	* Page83(Inquiry) (orzhang, p1)
 	* Page0 (Inquiry) (orzhang, p1)
 	* Define Device UUID
-	* More SCSI flags (carmark, p1)
-	* Read8,16 (carmark, p1)
 	* Verify (carmark, p1)
 	* Support `Target Group` and `Target Port` (p3)
 * Refactor (carmark, p1)

pkg/scsi/backingstore/common.go

@@ -205,13 +205,13 @@ verify:
 		}
 	}
 	glog.Infof("io done %s", string(scb))
+	return nil
 sense:
 	if err != nil {
 		glog.Error(err)
 		return err
 	}
-	_ = key
-	_ = asc
 
-	return nil
+	err = fmt.Errorf("sense data encounter, key: %v, asc: %v", key, asc)
+	return err
 }

pkg/scsi/cmd.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2015 The GoStor Authors All rights reserved.
+Copyright 2016 The GoStor Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -24,13 +24,13 @@ type SCSIPRServiceAction byte
 type SCSIPRType byte
 
 var (
-	/* PERSISTENT_RESERVE_IN service action codes */
+	// PERSISTENT_RESERVE_IN service action codes
 	PR_IN_READ_KEYS           SCSIPRServiceAction = 0x00
 	PR_IN_READ_RESERVATION    SCSIPRServiceAction = 0x01
 	PR_IN_REPORT_CAPABILITIES SCSIPRServiceAction = 0x02
 	PR_IN_READ_FULL_STATUS    SCSIPRServiceAction = 0x03
 
-	/* PERSISTENT_RESERVE_OUT service action codes */
+	// PERSISTENT_RESERVE_OUT service action codes
 	PR_OUT_REGISTER                         SCSIPRServiceAction = 0x00
 	PR_OUT_RESERVE                          SCSIPRServiceAction = 0x01
 	PR_OUT_RELEASE                          SCSIPRServiceAction = 0x02
@@ -40,10 +40,10 @@ var (
 	PR_OUT_REGISTER_AND_IGNORE_EXISTING_KEY SCSIPRServiceAction = 0x06
 	PR_OUT_REGISTER_AND_MOVE                SCSIPRServiceAction = 0x07
 
-	/* Persistent Reservation scope */
+	// Persistent Reservation scope
 	PR_LU_SCOPE byte = 0x00
 
-	/* Persistent Reservation Type Mask format */
+	// Persistent Reservation Type Mask format
 	PR_TYPE_WRITE_EXCLUSIVE          SCSIPRType = 0x01
 	PR_TYPE_EXCLUSIVE_ACCESS         SCSIPRType = 0x03
 	PR_TYPE_WRITE_EXCLUSIVE_REGONLY  SCSIPRType = 0x05
@@ -53,31 +53,185 @@ var (
 )
 
 const (
-	CBD_GROUPID_0 = iota
+	CDB_GROUPID_0 = 6  /*  6-byte commands */
-	CBD_GROUPID_1
+	CDB_GROUPID_1 = 10 /* 10-byte commands */
-	CBD_GROUPID_2
+	CDB_GROUPID_2 = 10 /* 10-byte commands */
-	CBD_GROUPID_3
+	CDB_GROUPID_3 = 0  /* reserved */
-	CBD_GROUPID_4
+	CDB_GROUPID_4 = 16 /* 16-byte commands */
-	CBD_GROUPID_5
+	CDB_GROUPID_5 = 12 /* 12-byte commands */
-	CBD_GROUPID_6
+	CDB_GROUPID_6 = 0  /* vendor specific  */
-	CBD_GROUPID_7
+	CDB_GROUPID_7 = 0  /* vendor specific  */
-)
-
-const (
-	CDB_GROUP0 = 6  /*  6-byte commands */
-	CDB_GROUP1 = 10 /* 10-byte commands */
-	CDB_GROUP2 = 10 /* 10-byte commands */
-	CDB_GROUP3 = 0  /* reserved */
-	CDB_GROUP4 = 16 /* 16-byte commands */
-	CDB_GROUP5 = 12 /* 12-byte commands */
-	CDB_GROUP6 = 0  /* vendor specific  */
-	CDB_GROUP7 = 0  /* vendor specific  */
 )
 
 func SCSICDBGroupID(opcode byte) byte {
 	return ((opcode >> 5) & 0x7)
 }
 
+/*
+ * Protocol Identifier Values
+ *
+ * 0 Fibre Channel (FCP-2)
+ * 1 Parallel SCSI (SPI-5)
+ * 2 SSA (SSA-S3P)
+ * 3 IEEE 1394 (SBP-3)
+ * 4 SCSI Remote Direct Memory Access (SRP)
+ * 5 iSCSI
+ * 6 SAS Serial SCSI Protocol (SAS)
+ * 7 Automation/Drive Interface (ADT)
+ * 8 AT Attachment Interface (ATA/ATAPI-7)
+ */
+
+const (
+	PIV_FCP   = byte(0x00)
+	PIV_SPI   = byte(0x01)
+	PIV_S3P   = byte(0x02)
+	PIV_SBP   = byte(0x03)
+	PIV_SRP   = byte(0x04)
+	PIV_ISCSI = byte(0x05)
+	PIV_SAS   = byte(0x06)
+	PIV_ADT   = byte(0x07)
+	PIV_ATA   = byte(0x08)
+	PIV_USB   = byte(0x09)
+	PIV_SOP   = byte(0x0A)
+)
+
+const (
+	VERSION_NOT_CLAIM         = byte(0x00)
+	VERSION_WITHDRAW_STANDARD = byte(0x03)
+	VERSION_WITHDRAW_SPC2     = byte(0x04)
+	VERSION_WITHDRAW_SPC3     = byte(0x05)
+)
+
+/*
+ * Code Set
+ *
+ *  1 - Designator fild contains binary values
+ *  2 - Designator field contains ASCII printable chars
+ *  3 - Designaotor field contains UTF-8
+ */
+
+const (
+	INQ_CODE_BIN   = byte(1)
+	INQ_CODE_ASCII = byte(2)
+	INQ_CODE_UTF8  = byte(3)
+)
+
+/*
+ * Association field
+ *
+ * 00b - Associated with Logical Unit
+ * 01b - Associated with target port
+ * 10b - Associated with SCSI Target device
+ * 11b - Reserved
+ */
+
+const (
+	ASS_LU       = byte(0x00)
+	ASS_TGT_PORT = byte(0x01)
+	ASS_TGT_DEV  = byte(0x02)
+)
+
+/*
+ * Table 177 — PERIPHERAL QUALIFIER field
+ * Qualifier Description
+ * 000b - A peripheral device having the indicated peripheral
+ * 	device type is connected to this logical unit. If the device server is
+ * 	unable to determine whether or not a peripheral device is connected,
+ * 	then the device server also shall use this peripheral qualifier.
+ * 	This peripheral qualifier does not indicate that the peripheral
+ * 	device connected to the logical unit is ready for access.
+ * 001b - A peripheral device having the indicated peripheral device type
+ * 	is not connected to this logical unit. However, the device server is capable of
+ *	supporting the indicated peripheral device type on this logical unit.
+ * 010b - Reserved
+ * 011b - The device server is not capable of supporting a
+ * 	peripheral device on this logical unit. For this peripheral
+ *	qualifier the peripheral device type shall be set to 1Fh. All other peripheral
+ * device type values are reserved for this peripheral qualifier.
+ * 100b to 111b Vendor specific
+ */
+
+const (
+	PQ_DEVICE_CONNECTED   = byte(0x00 << 5)
+	PQ_DEVICE_NOT_CONNECT = byte(0x01 << 5)
+	PQ_RESERVED           = byte(0x02 << 5)
+	PQ_NOT_SUPPORT        = byte(0x03 << 5)
+)
+
+const (
+	INQUIRY_SCCS          = byte(0x80)
+	INQUIRY_AAC           = byte(0x40)
+	INQUIRY_TPGS_NO       = byte(0x00)
+	INQUIRY_TPGS_IMPLICIT = byte(0x20)
+	INQUIRY_TPGS_EXPLICIT = byte(0x10)
+	INQUIRY_TPGS_BOTH     = byte(0x30)
+	INQUIRY_3PC           = byte(0x08)
+	INQUIRY_Reserved      = byte(0x06)
+	INQUIRY_PROTECT       = byte(0x01)
+
+	INQUIRY_NORM_ACA        = byte(0x20)
+	INQUIRY_HISUP           = byte(0x10)
+	INQUIRY_STANDARD_FORMAT = byte(0x02)
+
+	INQUIRY_ENCSERV = byte(0x40)
+	INQUIRY_VS0     = byte(0x20)
+	INQUIRY_MULTIP  = byte(0x10)
+	INQUIRY_ADDR16  = byte(0x01)
+
+	INQUIRY_WBUS16 = byte(0x20)
+	INQUIRY_SYNC   = byte(0x10)
+	INQUIRY_CMDQUE = byte(0x02)
+	INQUIRY_VS1    = byte(0x01)
+
+	INQUIRY_QAS = byte(0x02)
+	INQUIRY_IUS = byte(0x01)
+)
+
+const (
+	ADDRESS_METHOD_PERIPHERAL_DEVICE     = byte(0x00)
+	ADDRESS_METHOD_FLAT_SPACE            = byte(0x01)
+	ADDRESS_METHOD_LOGICAL_UNIT          = byte(0x02)
+	ADDRESS_METHOD_EXTENDED_LOGICAL_UNIT = byte(0x03)
+)
+
+/*
+ * Designator type - SPC-4 Reference
+ *
+ * 0 - Vendor specific - 7.6.3.3
+ * 1 - T10 vendor ID - 7.6.3.4
+ * 2 - EUI-64 - 7.6.3.5
+ * 3 - NAA - 7.6.3.6
+ * 4 - Relative Target port identifier - 7.6.3.7
+ * 5 - Target Port group - 7.6.3.8
+ * 6 - Logical Unit group - 7.6.3.9
+ * 7 - MD5 logical unit identifier - 7.6.3.10
+ * 8 - SCSI name string - 7.6.3.11
+ */
+
+const (
+	DESG_VENDOR = iota
+	DESG_T10
+	DESG_EUI64
+	DESG_NAA
+	DESG_REL_TGT_PORT
+	DESG_TGT_PORT_GRP
+	DESG_LU_GRP
+	DESG_MD5
+	DESG_SCSI
+)
+
+const (
+	NAA_IEEE_EXTD      = byte(0x2)
+	NAA_LOCAL          = byte(0x3)
+	NAA_IEEE_REGD      = byte(0x5)
+	NAA_IEEE_REGD_EXTD = byte(0x6)
+)
+
+const (
+	SCSIVendorID  = "GOSTOR"
+	SCSIProductID = "GOTGT"
+)
+
 /*
  * Transfer Length (if any)
  * Parameter List Length (if any)
@@ -94,19 +248,19 @@ func SCSICDBBufXLength(scb []byte) (int64, bool) {
 	group = SCSICDBGroupID(opcode)
 
 	switch group {
-	case CBD_GROUPID_0:
+	case CDB_GROUPID_0:
 		length = int64(scb[4])
-	case CBD_GROUPID_1, CBD_GROUPID_2:
+	case CDB_GROUPID_2:
 		length = int64(util.GetUnalignedUint16(scb[7:9]))
-	case CBD_GROUPID_3:
+	case CDB_GROUPID_3:
 		if opcode == 0x7F {
 			length = int64(scb[7])
 		} else {
 			ok = false
 		}
-	case CBD_GROUPID_4:
+	case CDB_GROUPID_4:
 		length = int64(util.GetUnalignedUint32(scb[6:10]))
-	case CBD_GROUPID_5:
+	case CDB_GROUPID_5:
 		length = int64(util.GetUnalignedUint32(scb[10:14]))
 	default:
 		ok = false

pkg/scsi/sbc.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2015 The GoStor Authors All rights reserved.
+Copyright 2016 The GoStor Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -54,8 +54,8 @@ func (sbc SBCSCSIDeviceProtocol) InitLu(lu *api.SCSILu) error {
 	lu.Attrs.Readonly = false
 	lu.Attrs.SWP = false
 	lu.Attrs.SenseFormat = false
-	lu.Attrs.VendorID = SCSI_VendorID
+	lu.Attrs.VendorID = SCSIVendorID
-	lu.Attrs.ProductID = SCSI_ProductID
+	lu.Attrs.ProductID = SCSIProductID
 	lu.Attrs.ProductRev = version.SCSI_VERSION
 
 	/*
@@ -216,11 +216,17 @@ func SBCModeSense(host int, cmd *api.SCSICommand) api.SAMStat {
 	return api.SAMStatGood
 }
 
-// The FORMAT UNIT command requests that the device server format the medium into application client
+/*
-// accessible logical blocks as specified in the number of blocks and block length values received
+ * SBCFormatUnit Implements SCSI FORMAT UNIT command
-// in the last mode parameter block descriptor in a MODE SELECT command (see SPC-3).  In addition,
+ * The FORMAT UNIT command requests that the device server format the medium into application client
-// the device server may certify the medium and create control structures for the management of the medium and defects.
+ * accessible logical blocks as specified in the number of blocks and block length values received
-// The degree that the medium is altered by this command is vendor-specific.
+ * in the last mode parameter block descriptor in a MODE SELECT command (see SPC-3).  In addition,
+ * the device server may certify the medium and create control structures for the management of the medium and defects.
+ * The degree that the medium is altered by this command is vendor-specific.
+ *
+ * Reference : SBC2r16
+ * 5.2 - FORMAT UNIT
+ */
 func SBCFormatUnit(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		key = ILLEGAL_REQUEST
@@ -266,6 +272,24 @@ func SBCUnmap(host int, cmd *api.SCSICommand) api.SAMStat {
 	return api.SAMStatGood
 }
 
+/*
+ * SBCReadWrite Implements SCSI READ(10/12/16), WRITE(10/12/16), WRITE AND VERIFY(10/12/16), WRITE SAME(10/12/16)
+ * The READ command requests that the device server read the specified logical block(s) and transfer them to the data-in buffer.
+ * The WRITE command requests that the device server transfer the specified logical block(s) from the data-out buffer and write them.
+ * The WRITE AND VERIFY command requests that the device server transfer the specified logical block(s) from the data-out buffer,
+ * write them to the medium, and then verify that they are correctly written.
+ *
+ * Reference : SBC2r16
+ * 5.6 - READ (10)
+ * 5.7 - READ (12)
+ * 5.8 - READ (16)
+ * 5.25 - WRITE (10)
+ * 5.26 - WRITE (12)
+ * 5.27 - WRITE (16)
+ * 5.29 - WRITE AND VERIFY (10)
+ * 5.30 - WRITE AND VERIFY (12)
+ * 5.31 - WRITE AND VERIFY (16)
+ */
 func SBCReadWrite(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		key    = ILLEGAL_REQUEST
@@ -414,11 +438,17 @@ func SBCRelease(host int, cmd *api.SCSICommand) api.SAMStat {
 	return api.SAMStatGood
 }
 
-// The READ CAPACITY (10) command requests that the device server transfer 8 bytes of parameter data
+/*
-// describing the capacity and medium format of the direct-access block device to the data-in buffer.
+ * SBCReadCapacity Implements SCSI READ CAPACITY(10) command
-// This command may be processed as if it has a HEAD OF QUEUE task attribute.  If the logical unit supports
+ * The READ CAPACITY (10) command requests that the device server transfer 8 bytes of parameter data
-// protection information, the application client should use the READ CAPACITY (16) command instead of
+ * describing the capacity and medium format of the direct-access block device to the data-in buffer.
-// the READ CAPACITY (10) command.
+ * This command may be processed as if it has a HEAD OF QUEUE task attribute.  If the logical unit supports
+ * protection information, the application client should use the READ CAPACITY (16) command instead of
+ * the READ CAPACITY (10) command.
+ *
+ * Reference : SBC2r16
+ * 5.10 - READ CAPACITY(10)
+ */
 func SBCReadCapacity(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		scb    = cmd.SCB.Bytes()
@@ -465,7 +495,12 @@ sense:
 	return api.SAMStatCheckCondition
 }
 
-// The VERIFY (10) command requests that the device server verify the specified logical block(s) on the medium.
+/* SBCVerify Implements SCSI VERIFY(10) command
+ * The VERIFY (10) command requests that the device server verify the specified logical block(s) on the medium.
+ *
+ * Reference : SBC2r16
+ * 5.20 - VERIFY(10)
+ */
 func SBCVerify(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		key = ILLEGAL_REQUEST
@@ -495,6 +530,14 @@ sense:
 	return api.SAMStatCheckCondition
 }
 
+/*
+ * SBCReadCapacity16 Implements SCSI READ CAPACITY(16) command
+ * The READ CAPACITY (16) command requests that the device server transfer parameter data
+ * describing the capacity and medium format of the direct-access block device to the data-in buffer.
+ *
+ * Reference : SBC2r16
+ * 5.11 - READ CAPACITY(16)
+ */
 func SBCReadCapacity16(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		data   = &bytes.Buffer{}
@@ -526,9 +569,16 @@ func SBCServiceAction(host int, cmd *api.SCSICommand) api.SAMStat {
 	return api.SAMStatGood
 }
 
-// The SYNCHRONIZE CACHE (10) command requests that the device server ensure that
+/*
-// the specified logical blocks have their most recent data values recorded in
+ * SBCSyncCache Implements SCSI SYNCHRONIZE CACHE(10) and SYNCHRONIZE CACHE(16) command
-// non-volatile cache and/or on the medium, based on the SYNC_NV bit.
+ * The SYNCHRONIZE CACHE command requests that the device server ensure that
+ * the specified logical blocks have their most recent data values recorded in
+ * non-volatile cache and/or on the medium, based on the SYNC_NV bit.
+ *
+ * Reference : SBC2r16
+ * 5.18 - SYNCHRONIZE CACHE (10)
+ * 5.19 - SYNCHRONIZE CACHE (16)
+ */
 func SBCSyncCache(host int, cmd *api.SCSICommand) api.SAMStat {
 	return api.SAMStatGood
 }

pkg/scsi/spc.go

@@ -27,171 +27,6 @@ import (
 	"github.com/gostor/gotgt/pkg/util"
 )
 
-/*
- * Protocol Identifier Values
- *
- * 0 Fibre Channel (FCP-2)
- * 1 Parallel SCSI (SPI-5)
- * 2 SSA (SSA-S3P)
- * 3 IEEE 1394 (SBP-3)
- * 4 SCSI Remote Direct Memory Access (SRP)
- * 5 iSCSI
- * 6 SAS Serial SCSI Protocol (SAS)
- * 7 Automation/Drive Interface (ADT)
- * 8 AT Attachment Interface (ATA/ATAPI-7)
- */
-
-const (
-	PIV_FCP   = byte(0x00)
-	PIV_SPI   = byte(0x01)
-	PIV_S3P   = byte(0x02)
-	PIV_SBP   = byte(0x03)
-	PIV_SRP   = byte(0x04)
-	PIV_ISCSI = byte(0x05)
-	PIV_SAS   = byte(0x06)
-	PIV_ADT   = byte(0x07)
-	PIV_ATA   = byte(0x08)
-	PIV_USB   = byte(0x09)
-	PIV_SOP   = byte(0x0A)
-)
-
-const (
-	VERSION_NOT_CLAIM         = byte(0x00)
-	VERSION_WITHDRAW_STANDARD = byte(0x03)
-	VERSION_WITHDRAW_SPC2     = byte(0x04)
-	VERSION_WITHDRAW_SPC3     = byte(0x05)
-)
-
-/*
- * Code Set
- *
- *  1 - Designator fild contains binary values
- *  2 - Designator field contains ASCII printable chars
- *  3 - Designaotor field contains UTF-8
- */
-
-const (
-	INQ_CODE_BIN   = byte(1)
-	INQ_CODE_ASCII = byte(2)
-	INQ_CODE_UTF8  = byte(3)
-)
-
-/*
- * Association field
- *
- * 00b - Associated with Logical Unit
- * 01b - Associated with target port
- * 10b - Associated with SCSI Target device
- * 11b - Reserved
- */
-
-const (
-	ASS_LU       = byte(0x00)
-	ASS_TGT_PORT = byte(0x01)
-	ASS_TGT_DEV  = byte(0x02)
-)
-
-/*
- * Table 177 — PERIPHERAL QUALIFIER field
- * Qualifier Description
- * 000b - A peripheral device having the indicated peripheral
- * 	device type is connected to this logical unit. If the device server is
- * 	unable to determine whether or not a peripheral device is connected,
- * 	then the device server also shall use this peripheral qualifier.
- * 	This peripheral qualifier does not indicate that the peripheral
- * 	device connected to the logical unit is ready for access.
- * 001b - A peripheral device having the indicated peripheral device type
- * 	is not connected to this logical unit. However, the device server is capable of
- *	supporting the indicated peripheral device type on this logical unit.
- * 010b - Reserved
- * 011b - The device server is not capable of supporting a
- * 	peripheral device on this logical unit. For this peripheral
- *	qualifier the peripheral device type shall be set to 1Fh. All other peripheral
- * device type values are reserved for this peripheral qualifier.
- * 100b to 111b Vendor specific
- */
-
-const (
-	PQ_DEVICE_CONNECTED   = byte(0x00 << 5)
-	PQ_DEVICE_NOT_CONNECT = byte(0x01 << 5)
-	PQ_RESERVED           = byte(0x02 << 5)
-	PQ_NOT_SUPPORT        = byte(0x03 << 5)
-)
-
-const (
-	INQUIRY_SCCS          = byte(0x80)
-	INQUIRY_AAC           = byte(0x40)
-	INQUIRY_TPGS_NO       = byte(0x00)
-	INQUIRY_TPGS_IMPLICIT = byte(0x10)
-	INQUIRY_TPGS_EXPLICIT = byte(0x20)
-	INQUIRY_TPGS_BOTH     = byte(0x30)
-	INQUIRY_3PC           = byte(0x08)
-	INQUIRY_Reserved      = byte(0x06)
-	INQUIRY_PROTECT       = byte(0x01)
-
-	INQUIRY_NORM_ACA        = byte(0x20)
-	INQUIRY_HISUP           = byte(0x10)
-	INQUIRY_STANDARD_FORMAT = byte(0x02)
-
-	INQUIRY_ENCSERV = byte(0x40)
-	INQUIRY_VS0     = byte(0x20)
-	INQUIRY_MULTIP  = byte(0x10)
-	INQUIRY_ADDR16  = byte(0x01)
-
-	INQUIRY_WBUS16 = byte(0x20)
-	INQUIRY_SYNC   = byte(0x10)
-	INQUIRY_CMDQUE = byte(0x02)
-	INQUIRY_VS1    = byte(0x01)
-
-	INQUIRY_QAS = byte(0x02)
-	INQUIRY_IUS = byte(0x01)
-)
-
-const (
-	ADDRESS_METHOD_PERIPHERAL_DEVICE     = byte(0x00)
-	ADDRESS_METHOD_FLAT_SPACE            = byte(0x01)
-	ADDRESS_METHOD_LOGICAL_UNIT          = byte(0x02)
-	ADDRESS_METHOD_EXTENDED_LOGICAL_UNIT = byte(0x03)
-)
-
-/*
- * Designator type - SPC-4 Reference
- *
- * 0 - Vendor specific - 7.6.3.3
- * 1 - T10 vendor ID - 7.6.3.4
- * 2 - EUI-64 - 7.6.3.5
- * 3 - NAA - 7.6.3.6
- * 4 - Relative Target port identifier - 7.6.3.7
- * 5 - Target Port group - 7.6.3.8
- * 6 - Logical Unit group - 7.6.3.9
- * 7 - MD5 logical unit identifier - 7.6.3.10
- * 8 - SCSI name string - 7.6.3.11
- */
-
-const (
-	DESG_VENDOR = iota
-	DESG_T10
-	DESG_EUI64
-	DESG_NAA
-	DESG_REL_TGT_PORT
-	DESG_TGT_PORT_GRP
-	DESG_LU_GRP
-	DESG_MD5
-	DESG_SCSI
-)
-
-const (
-	NAA_IEEE_EXTD      = byte(0x2)
-	NAA_LOCAL          = byte(0x3)
-	NAA_IEEE_REGD      = byte(0x5)
-	NAA_IEEE_REGD_EXTD = byte(0x6)
-)
-
-const (
-	SCSI_VendorID  = "GOSTOR"
-	SCSI_ProductID = "GOTGT"
-)
-
 func SPCIllegalOp(host int, cmd *api.SCSICommand) api.SAMStat {
 	BuildSenseData(cmd, ILLEGAL_REQUEST, ASC_INVALID_FIELD_IN_CDB)
 	return api.SAMStatCheckCondition
@@ -360,6 +195,13 @@ func InquiryPage0x83(host int, cmd *api.SCSICommand) (*bytes.Buffer, uint16) {
 	return buf, pageLength
 }
 
+/*
+ * SPCInquiry Implements SCSI INQUIRY command
+ * The INQUIRY command requests the device server to return information regarding the logical unit and SCSI target device.
+ *
+ * Reference : SPC4r11
+ * 6.6 - INQUIRY
+ */
 func SPCInquiry(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		allocationLength uint16
@@ -478,6 +320,14 @@ sense:
 	return api.SAMStatCheckCondition
 }
 
+/*
+ * SPCReportLuns Implements SCSI REPORT LUNS command
+ * The REPORT LUNS command requests the device server to return the peripheral Device
+ * logical unit inventory accessible to the I_T nexus.
+ *
+ * Reference : SPC4r11
+ * 6.33 - REPORT LUNS
+ */
 func SPCReportLuns(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		remainLength     uint32
@@ -576,6 +426,13 @@ func SPCStartStop(host int, cmd *api.SCSICommand) api.SAMStat {
 	return api.SAMStatGood
 }
 
+/*
+ * SPCTestUnit Implements SCSI TEST UNIT READY command
+ * The TEST UNIT READY command requests the device server to indicate whether the logical unit is ready.
+ *
+ * Reference : SPC4r11
+ * 6.47 - TEST UNIT READY
+ */
 func SPCTestUnit(host int, cmd *api.SCSICommand) api.SAMStat {
 	/*
 		if err := deviceReserve(cmd); err != nil {
@@ -603,10 +460,15 @@ func SPCPreventAllowMediaRemoval(host int, cmd *api.SCSICommand) api.SAMStat {
 	return api.SAMStatGood
 }
 
-// SPCModeSense Implement SCSI op MODE SENSE(6) and MODE SENSE(10)
+/*
-//  Reference : SPC4r11
+ * SPCModeSense Implement SCSI MODE SENSE(6) and MODE SENSE(10) command
-//  6.11 - MODE SENSE(6)
+ * The MODE SENSE command requests the device server to return the specified medium,
-//  6.12 - MODE SENSE(10)
+ * logical unit, or peripheral device parameters.
+ *
+ * Reference : SPC4r11
+ * 6.11 - MODE SENSE(6)
+ * 6.12 - MODE SENSE(10)
+ */
 func SPCModeSense(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		scb            = cmd.SCB.Bytes()
@@ -637,6 +499,14 @@ sense:
 	return api.SAMStatCheckCondition
 }
 
+/*
+ * SPCSendDiagnostics Implements SCSI SEND DIAGNOSTIC command
+ * The SEND DIAGNOSTIC command requests the device server to perform diagnostic operations
+ * on the SCSI target device, on the logical unit, or on both.
+ *
+ * Reference : SPC4r11
+ * 6.42 - SEND DIAGNOSTIC
+ */
 func SPCSendDiagnostics(host int, cmd *api.SCSICommand) api.SAMStat {
 	// we only support SELF-TEST==1
 	if cmd.SCB.Bytes()[1]&0x04 == 0 {
@@ -826,6 +696,13 @@ func SPCPRRegisterAndMove(host int, cmd *api.SCSICommand) api.SAMStat {
 	return api.SAMStatGood
 }
 
+/*
+ * SPCRequestSense Implements SCSI REQUEST SENSE command
+ * The REQUEST SENSE command requests the device server to return parameter data that contains sense data.
+ *
+ * Reference : SPC4r11
+ * 6.39 - REQUEST SENSE
+ */
 func SPCRequestSense(host int, cmd *api.SCSICommand) api.SAMStat {
 	var (
 		allocationLength uint32
@@ -844,7 +721,7 @@ func SPCRequestSense(host int, cmd *api.SCSICommand) api.SAMStat {
 		actualLength = allocationLength
 	}
 	if cmd.SenseBuffer != nil {
-		data.Write(cmd.SenseBuffer.Bytes()[0:actualLength])
+		data.Write(cmd.SenseBuffer.Bytes()[:actualLength])
 	}
 	cmd.InSDBBuffer.Resid = int32(actualLength)
 	cmd.InSDBBuffer.Buffer = data