[stgt] [PATCH 2/3] SBC: add minimal support for FORMAT-UNIT

[Ronnie Sahlberg]

FORMAT-UNIT is Mandatory for SBC devices.
At minimum (SBC 5.2.1 FORMAT UNIT COMMAND OVERVIEW)
a SBC device must support the basic FORMAT-UNIT command
with FMTDATA == 0 and DEFECT LIST FORMAT == 000b

No protection information is created with this kind of formatting.

For this specific request that is mandatory, return status ok
but dont actually do anything.

For all optional versions of FORMAT-UNIT just return
ILLEGAL-REQUEST/INVALID_FIELD_IN_CDB

Signed-off-by: Ronnie Sahlberg <ronniesahlberg at gmail.com>
---
 usr/sbc.c |   44 +++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 43 insertions(+), 1 deletions(-)

diff --git a/usr/sbc.c b/usr/sbc.c
index b5843af..b7bff8d 100644
--- a/usr/sbc.c
+++ b/usr/sbc.c
@@ -99,6 +99,48 @@ static int sbc_mode_sense(int host_no, struct scsi_cmd *cmd)
 	return ret;
 }
 
+static int sbc_format_unit(int host_no, struct scsi_cmd *cmd)
+{
+	unsigned char key = ILLEGAL_REQUEST;
+	uint16_t asc = ASC_INVALID_FIELD_IN_CDB;
+	int ret;
+
+	ret = device_reserved(cmd);
+	if (ret)
+		return SAM_STAT_RESERVATION_CONFLICT;
+
+	if (!cmd->dev->attrs.online) {
+		key = NOT_READY;
+		asc = ASC_MEDIUM_NOT_PRESENT;
+		goto sense;
+	}
+
+	if (cmd->dev->attrs.readonly) {
+		key = DATA_PROTECT;
+		asc = ASC_WRITE_PROTECT;
+		goto sense;
+	}
+
+	if (cmd->scb[1] & 0x80) {
+		/* we dont support format protection information */
+		goto sense;
+	}
+	if (cmd->scb[1] & 0x10) {
+		/* we dont support format data */
+		goto sense;
+	}
+	if (cmd->scb[1] & 0x07) {
+		/* defect list format must be 0 */
+		goto sense;
+	}
+
+	return SAM_STAT_GOOD;
+
+sense:
+	sense_data_build(cmd, key, asc);
+	return SAM_STAT_CHECK_CONDITION;
+}
+
 static int sbc_rw(int host_no, struct scsi_cmd *cmd)
 {
 	int ret;
@@ -353,7 +395,7 @@ static struct device_type_template sbc_template = {
 		{spc_illegal_op,},
 		{spc_illegal_op,},
 		{spc_request_sense,},
-		{spc_illegal_op,},
+		{sbc_format_unit,},
 		{spc_illegal_op,},
 		{spc_illegal_op,},
 		{spc_illegal_op,},
-- 
1.7.3.1

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