[PATCH v3 3/4] libmultipath: add uid failback for dasd devices

[Benjamin Marzinski <bmarzins@xxxxxxxxxx>]

Add failback code to get the uid for dasd devices from sysfs. Copied
from dasdinfo

Reviewed-by: Martin Wilck <mwilck@xxxxxxxx>
Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
---
 libmultipath/defaults.h  |  1 +
 libmultipath/discovery.c | 37 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h
index 39a5e415..947ba467 100644
--- a/libmultipath/defaults.h
+++ b/libmultipath/defaults.h
@@ -8,6 +8,7 @@
  */
 #define DEFAULT_UID_ATTRIBUTE	"ID_SERIAL"
 #define DEFAULT_NVME_UID_ATTRIBUTE	"ID_WWN"
+#define DEFAULT_DASD_UID_ATTRIBUTE	"ID_UID"
 #define DEFAULT_UDEVDIR		"/dev"
 #define DEFAULT_MULTIPATHDIR	"/" LIB_STRING "/multipath"
 #define DEFAULT_SELECTOR	"service-time 0"
diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index cbde3585..d7e8577f 100644
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -1957,12 +1957,44 @@ get_vpd_uid(struct path * pp)
 	return get_vpd_sysfs(parent, 0x83, pp->wwid, WWID_SIZE);
 }
 
+/* based on code from s390-tools/dasdinfo/dasdinfo.c */
+static ssize_t dasd_get_uid(struct path *pp)
+{
+	struct udev_device *parent;
+	char value[80];
+	char *p;
+	int i;
+
+	parent = udev_device_get_parent_with_subsystem_devtype(pp->udev, "ccw",
+							       NULL);
+	if (!parent)
+		return -1;
+
+	if (sysfs_attr_get_value(parent, "uid", value, 80) < 0)
+		return -1;
+
+	p = value - 1;
+	/* look for the 4th '.' and cut there */
+	for (i = 0; i < 4; i++) {
+		p = index(p + 1, '.');
+		if (!p)
+			break;
+	}
+	if (p)
+		*p = '\0';
+
+	return strlcpy(pp->wwid, value, WWID_SIZE);
+}
+
 static ssize_t uid_fallback(struct path *pp, int path_state,
 			    const char **origin)
 {
 	ssize_t len = -1;
 
-	if (pp->bus == SYSFS_BUS_SCSI) {
+	if (pp->bus == SYSFS_BUS_CCW) {
+		len = dasd_get_uid(pp);
+		*origin = "sysfs";
+	} else if (pp->bus == SYSFS_BUS_SCSI) {
 		len = get_vpd_uid(pp);
 		*origin = "sysfs";
 		if (len < 0 && path_state == PATH_UP) {
@@ -2010,6 +2042,9 @@ static bool has_uid_fallback(struct path *pp)
 		  !strcmp(pp->uid_attribute, ""))) ||
 		(pp->bus == SYSFS_BUS_NVME &&
 		 (!strcmp(pp->uid_attribute, DEFAULT_NVME_UID_ATTRIBUTE) ||
+		  !strcmp(pp->uid_attribute, ""))) ||
+		(pp->bus == SYSFS_BUS_CCW &&
+		 (!strcmp(pp->uid_attribute, DEFAULT_DASD_UID_ATTRIBUTE) ||
 		  !strcmp(pp->uid_attribute, ""))));
 }
 
-- 
2.17.2

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