[dm-devel] [PATCH 13/21] libmultipath: clariion checker: leave unsupported paths alone

[Martin Wilck]

A checker shouldn't set the path state to PATH_DOWN if it fails
to obtain information about the path in the first place. Add logic
to the checker to distinguish a failed path from an unsupported path.

Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 libmultipath/checkers/emc_clariion.c | 50 ++++++++++++++++++++++++++--
 1 file changed, 48 insertions(+), 2 deletions(-)

diff --git a/libmultipath/checkers/emc_clariion.c b/libmultipath/checkers/emc_clariion.c
index f8e55b93..a277a004 100644
--- a/libmultipath/checkers/emc_clariion.c
+++ b/libmultipath/checkers/emc_clariion.c
@@ -20,6 +20,11 @@
 #define INQUIRY_CMD     0x12
 #define INQUIRY_CMDLEN  6
 #define HEAVY_CHECK_COUNT       10
+#define SCSI_COMMAND_TERMINATED	0x22
+#define SCSI_CHECK_CONDITION	0x2
+#define RECOVERED_ERROR		0x01
+#define ILLEGAL_REQUEST		0x05
+#define SG_ERR_DRIVER_SENSE	0x08
 
 /*
  * Mechanism to track CLARiiON inactive snapshot LUs.
@@ -130,7 +135,9 @@ int libcheck_check (struct checker * c)
 		(struct emc_clariion_checker_path_context *)c->context;
 	char wwnstr[33];
 	int ret;
+	int retry_emc = 5;
 
+retry:
 	memset(&io_hdr, 0, sizeof (struct sg_io_hdr));
 	memset(sense_buffer, 0, 128);
 	memset(sb, 0, SENSE_BUFF_LEN);
@@ -145,12 +152,51 @@ int libcheck_check (struct checker * c)
 	io_hdr.timeout = c->timeout * 1000;
 	io_hdr.pack_id = 0;
 	if (ioctl(c->fd, SG_IO, &io_hdr) < 0) {
+		if (errno == ENOTTY) {
+			c->msgid = CHECKER_MSGID_UNSUPPORTED;
+			return PATH_WILD;
+		}
 		c->msgid = MSG_CLARIION_QUERY_FAILED;
 		return PATH_DOWN;
 	}
+
 	if (io_hdr.info & SG_INFO_OK_MASK) {
-		c->msgid = MSG_CLARIION_QUERY_ERROR;
-		return PATH_DOWN;
+		switch (io_hdr.host_status) {
+		case DID_BUS_BUSY:
+		case DID_ERROR:
+		case DID_SOFT_ERROR:
+		case DID_TRANSPORT_DISRUPTED:
+			/* Transport error, retry */
+			if (--retry_emc)
+				goto retry;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (SCSI_CHECK_CONDITION == io_hdr.status ||
+	    SCSI_COMMAND_TERMINATED == io_hdr.status ||
+	    SG_ERR_DRIVER_SENSE == (0xf & io_hdr.driver_status)) {
+		if (io_hdr.sbp && (io_hdr.sb_len_wr > 2)) {
+			unsigned char *sbp = io_hdr.sbp;
+			int sense_key;
+
+			if (sbp[0] & 0x2)
+				sense_key = sbp[1] & 0xf;
+			else
+				sense_key = sbp[2] & 0xf;
+
+			if (sense_key == ILLEGAL_REQUEST) {
+				c->msgid = CHECKER_MSGID_UNSUPPORTED;
+				return PATH_WILD;
+			} else if (sense_key != RECOVERED_ERROR) {
+				condlog(1, "emc_clariion_checker: INQUIRY failed with sense key %02x",
+					sense_key);
+				c->msgid = MSG_CLARIION_QUERY_ERROR;
+				return PATH_DOWN;
+			}
+		}
 	}
 	if (/* Verify the code page - right page & revision */
 	    sense_buffer[1] != 0xc0 || sense_buffer[9] != 0x00) {
-- 
2.19.0