On 05/05/2011 08:32 AM, Martin Schwenke wrote:
multipathd currently marks paths as down if they don't have a sysfs
"state" attribute.
Unfortunately, this makes multipathd unusable with Linux virtio_blk
devices, since they don't have this attribute. I need to use multipath
with virtio for consistency with a real configuration when testing a
clustered NAS system - yeah, I'm that guy again... :-)
One way of working around this might be to have path_offline() return
PATH_UP for all devices that don't have a sysfs "state" attribute,
instead of PATH_WILD. However, I'm guessing the current behaviour might
exist for a reason.
The following patch makes path_offline() always return PATH_UP instead
of PATH_WILD for virtio_blk devices. I've implemented the nested if
statements as below to change the code flow as little as possible
when sysfs_get_state() actually succeeds, which I assume is usually the
case. If nobody is feeling paranoid then the check for virtio_blk
could obviously be done before the call to sysfs_get_state().
If people think this patch is too specific then at least it can be
used to start a discussion... ;-)
Argl. They messed it up _again_.
(Speaking as someone who is in the process of cleaning up his patch
queue for multipath. Should have done that _far_ earlier :-( )
path_offline() _absolutely_ requires a check if the device is
actually a SCSI device. We do have several others to contend with
(cciss, dasd), and none of those do have the 'state' attribute.
So we need this patch
diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index 6cd2ec9..4af0cd3 100644
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -645,6 +645,10 @@ path_offline (struct path * pp)
struct sysfs_device * parent;
char buff[SCSI_STATE_SIZE];
+ if (pp->bus != SYSFS_BUS_SCSI)
+ /* No information for non-SCSI devices, return UP */
+ return PATH_UP;
+
pp->sysdev = sysfs_device_from_path(pp);
if (!pp->sysdev) {
condlog(1, "%s: failed to get sysfs information",
pp->dev);
And you need to implement virtio_blk as it's own bus type.
(Say SYSFS_BUS_VIRTIO). And teach discovery.c to detect this one
properly.
Look at 'cciss' and 'dasd' on how that's done.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
