path_id: rework SAS device handling

Lun numbers < 256 are displayed as "lun-x".  Lun numbers >= 256 use
the lun number format previously used in fibre channel by-path
links, 0xabcd012300000000. This lun numbering scheme is implemented
for sas, fibre channel, iscsi.

I want it to be clearly understood that this patch changes the
/dev/disk/by-path names for fc devices.  Here is an example of the
change:
  Old: pci-0000:0c:00.1-fc-0x204700a0b81130aa:0x00fa000000000000
  New: pci-0000:0c:00.1-fc-0x204700a0b81130aa-lun-250

diff --git a/extras/path_id/path_id.c b/extras/path_id/path_id.c
index 518ec8b386a782596404a1cd3aede55a60cb9593..62d26d8c4d5b759b88548050a568e35e7ee69240 100644 (file)
--- a/extras/path_id/path_id.c
+++ b/extras/path_id/path_id.c
@@ -75,6 +75,21 @@ static int path_prepend(char **path, const char *fmt, ...)
        return 0;
 }
 
+/*
+** Linux only supports 32 bit luns.
+** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
+*/
+static int format_lun_number(struct udev_device *dev, char **path)
+{
+       unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);
+
+       /* address method 0, peripheral device addressing with bus id of zero */
+       if (lun < 256)
+               return path_prepend(path, "lun-%d", lun);
+       /* handle all other lun addressing methods by using a variant of the original lun format */
+       return path_prepend(path, "lun-0x%04x%04x00000000", (lun & 0xffff), (lun >> 16) & 0xffff);
+}
+
 static struct udev_device *skip_subsystem(struct udev_device *dev, const char *subsys)
 {
        struct udev_device *parent = dev;
@@ -97,7 +112,7 @@ static struct udev_device *handle_scsi_fibre_channel(struct udev_device *parent,
        struct udev_device *targetdev;
        struct udev_device *fcdev = NULL;
        const char *port;
-       unsigned int lun;
+       char *lun = NULL;;
 
        targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
        if (targetdev == NULL)
@@ -112,8 +127,10 @@ static struct udev_device *handle_scsi_fibre_channel(struct udev_device *parent,
                goto out;
        }
 
-       lun = strtoul(udev_device_get_sysnum(parent), NULL, 10);
-       path_prepend(path, "fc-%s:0x%04x%04x00000000", port, lun & 0xffff, (lun >> 16) & 0xffff);
+       format_lun_number(parent, &lun);
+       path_prepend(path, "fc-%s-%s", port, lun);
+       if (lun)
+               free(lun);
 out:
        udev_device_unref(fcdev);
        return parent;
@@ -121,7 +138,39 @@ out:
 
 static struct udev_device *handle_scsi_sas(struct udev_device *parent, char **path)
 {
-       return NULL;
+       struct udev *udev  = udev_device_get_udev(parent);
+       struct udev_device *targetdev;
+       struct udev_device *target_parent;
+       struct udev_device *sasdev;
+       const char *sas_address;
+       char *lun = NULL;
+
+       targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
+       if (targetdev == NULL)
+               return NULL;
+
+       target_parent = udev_device_get_parent(targetdev);
+       if (target_parent == NULL)
+               return NULL;
+
+       sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device", 
+                               udev_device_get_sysname(target_parent));
+       if (sasdev == NULL)
+               return NULL;
+
+       sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
+       if (sas_address == NULL) {
+               parent = NULL;
+               goto out;
+       }
+
+       format_lun_number(parent, &lun);
+       path_prepend(path, "sas-%s-%s", sas_address, lun);
+       if (lun)
+               free(lun);
+out:
+       udev_device_unref(sasdev);
+       return parent;
 }
 
 static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **path)
@@ -134,6 +183,7 @@ static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **
        struct udev_device *conndev = NULL;
        const char *addr;
        const char *port;
+       char *lun = NULL;
 
        /* find iscsi session */
        transportdev = parent;
@@ -172,7 +222,10 @@ static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **
                goto out;
        }
 
-       path_prepend(path, "ip-%s:%s-iscsi-%s-lun-%s", addr, port, target, udev_device_get_sysnum(parent));
+       format_lun_number(parent, &lun);
+       path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
+       if (lun)
+               free(lun);
 out:
        udev_device_unref(sessiondev);
        udev_device_unref(conndev);