On 2/25/26 16:36, John Garry wrote:
Introduce a new class for multipathed devices, scsi_mpath_device_class.
The purpose of this class is for managing the scsi_mpath_head.dev member.
The naming for the scsi_device structure is in form H:C:I:L,
where H is host, C is channel, I is ID, and L is lun.
However, for a multipathed scsi_device, all the naming members may be
different between member scsi_device's. As such, just use a simple
single-number naming index for each scsi_mpath_head.
The sysfs device folder will have links to the scsi_device's so, it will
be possible to lookup the member scsi_device's.
An example sysfs entry is as follows:
# ls -l /sys/class/scsi_mpath_device/0/
total 0
drwxr-xr-x 2 root root 0 Feb 24 11:56 power
lrwxrwxrwx 1 root root 0 Feb 24 11:56 subsystem ->
../../../../class/scsi_mpath_device
-rw-r--r-- 1 root root 4096 Feb 24 11:55 uevent
-r--r--r-- 1 root root 4096 Feb 24 11:56 wwid
# cat /sys/class/scsi_mpath_device/0/wwid
naa.600140505200a986f0043c9afa1fd077
Ah, here it is.
So you can ignore my comments from the previous patch.
(and you might think of merging this and the previous patch).
But device naming is still dodgy. A plain number has so many ways of
being misinterpreted.
Wouldn't it be better to name it 'mpathX' ?
And, of course: how can we get the topology?
Do we get a list of the underlying scsi devices from sysfs?
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
[email protected] +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
