Re: [PATCH 3/8] target: Fail I/O with PROTECT bit when protection is unsupported

Sagi Grimberg <sagig@xxxxxxxxxxxxxxxxxx> · Sun, 15 Feb 2015 10:33:40 +0200

On 2/14/2015 5:27 AM, Nicholas A. Bellinger wrote:
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

This patch adds an explicit check for WRPROTECT + RDPROTECT bit usage
within sbc_check_prot(), and fails with TCM_INVALID_CDB_FIELD if the
backend device does not have protection enabled.

Also, update sbc_check_prot() to return sense_reason_t in order to
propigate up the correct sense ASQ.

Cc: Martin Petersen <martin.petersen@xxxxxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
  drivers/target/target_core_sbc.c | 51 +++++++++++++++++++++++++---------------
  1 file changed, 32 insertions(+), 19 deletions(-)

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 17259c0..1bb8b4a 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -626,14 +626,21 @@ sbc_set_prot_op_checks(u8 protect, enum target_prot_type prot_type,
  	return 0;
  }

-static bool
+static sense_reason_t
  sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
  	       u32 sectors, bool is_write)
  {
  	u8 protect = cdb[1] >> 5;

-	if ((!cmd->t_prot_sg || !cmd->t_prot_nents) && cmd->prot_pto)
-		return true;
+	if (!cmd->t_prot_sg || !cmd->t_prot_nents) {
+		if (protect && !dev->dev_attrib.pi_prot_type) {
+			pr_err("CDB contains protect bit, but device does not"
+			       " advertise PROTECT=1 feature bit\n");
+			return TCM_INVALID_CDB_FIELD;
+		}
+		if (cmd->prot_pto)
+			return TCM_NO_SENSE;
+	}

I think this should indicate a strip operation rather than a failure.
Depends on what we reported in readcapacity wrt backend/frontend
support & setting.


  	switch (dev->dev_attrib.pi_prot_type) {
  	case TARGET_DIF_TYPE3_PROT:
@@ -641,7 +648,7 @@ sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
  		break;
  	case TARGET_DIF_TYPE2_PROT:
  		if (protect)
-			return false;
+			return TCM_INVALID_CDB_FIELD;

  		cmd->reftag_seed = cmd->t_task_lba;
  		break;
@@ -650,12 +657,12 @@ sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
  		break;
  	case TARGET_DIF_TYPE0_PROT:
  	default:
-		return true;
+		return TCM_NO_SENSE;
  	}

  	if (sbc_set_prot_op_checks(protect, dev->dev_attrib.pi_prot_type,
  				   is_write, cmd))
-		return false;
+		return TCM_INVALID_CDB_FIELD;

  	cmd->prot_type = dev->dev_attrib.pi_prot_type;
  	cmd->prot_length = dev->prot_length * sectors;
@@ -674,7 +681,7 @@ sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
  		 __func__, cmd->prot_type, cmd->data_length, cmd->prot_length,
  		 cmd->prot_op, cmd->prot_checks);

-	return true;
+	return TCM_NO_SENSE;
  }

  sense_reason_t
@@ -698,8 +705,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
  		sectors = transport_get_sectors_10(cdb);
  		cmd->t_task_lba = transport_lba_32(cdb);

-		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
-			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
+		if (ret)
+			return ret;

  		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
  		cmd->execute_rw = ops->execute_rw;
@@ -709,8 +717,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
  		sectors = transport_get_sectors_12(cdb);
  		cmd->t_task_lba = transport_lba_32(cdb);

-		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
-			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
+		if (ret)
+			return ret;

  		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
  		cmd->execute_rw = ops->execute_rw;
@@ -720,8 +729,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
  		sectors = transport_get_sectors_16(cdb);
  		cmd->t_task_lba = transport_lba_64(cdb);

-		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
-			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
+		if (ret)
+			return ret;

  		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
  		cmd->execute_rw = ops->execute_rw;
@@ -739,8 +749,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
  		sectors = transport_get_sectors_10(cdb);
  		cmd->t_task_lba = transport_lba_32(cdb);

-		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
-			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, true);
+		if (ret)
+			return ret;

  		if (cdb[1] & 0x8)
  			cmd->se_cmd_flags |= SCF_FUA;
@@ -752,8 +763,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
  		sectors = transport_get_sectors_12(cdb);
  		cmd->t_task_lba = transport_lba_32(cdb);

-		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
-			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, true);
+		if (ret)
+			return ret;

  		if (cdb[1] & 0x8)
  			cmd->se_cmd_flags |= SCF_FUA;
@@ -765,8 +777,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
  		sectors = transport_get_sectors_16(cdb);
  		cmd->t_task_lba = transport_lba_64(cdb);

-		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
-			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, true);
+		if (ret)
+			return ret;

  		if (cdb[1] & 0x8)
  			cmd->se_cmd_flags |= SCF_FUA;


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