Re: [libvirt] [PATCH 00/11] Allow creation of vHBA by parent_wwnn/wwpn or fabric_name
On 12/12/2016 07:50 PM, Jim Fehlig wrote:
On 12/03/2016 07:09 AM, John Ferlan wrote:
>
> ping?
Sorry, I seem to have lost your initial cover letter so responding here...
>
> On 11/18/2016 09:26 AM, John Ferlan wrote:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1349696
>>
>> Lots of details in the bz, but essentially the problem is that providing
>> a "parent" scsi_hostX value has drawbacks on reboots because what was
>> scsi_hostX could turn into scsi_hostY on subsequent reboots.
>>
>> So add the ability to use the parent wwnn/wwpn or fabric_wwn as 'search'
>> criteria in order to create either non persistent vHBA's via nodedev or
>> persistent vHBA's via storage pools.
I've not looked at all the patches in detail, but I have been giving
them a fair bit of testing and haven't noticed any problems thus far.
Thanks - that's good to know...
Once question I do have is related to volume detection in
vport-based
pools. Currently when there are multiple paths to a LUN only the active
ones are displayed in the pool. Inactive paths are ignored since
saferead() fails in
src/storage/storage_backend.c:virStorageBackendDetectBlockVolFormatFD().
Without the inactive paths, there would be no path to the LUN if it was
trespassed. I made the below hack to
virStorageBackendUpdateVolTargetInfo() to show the inactive paths too,
and was able to pass those to the guest allowing it to handle
multipathing. Is there a reason the inactive paths are ignored?
I suppose for NPIV/vHBA LUN's it perhaps makes sense to have inactive
paths. Been a while since I went down that path...
Seems like virStorageBackendSCSINewLun should be able to receive a -2 in
order to ignore VIR_STORAGE_VOL_READ_NOERROR. There's a sequence of
changes I made starting with commit id '22346003d' which allow/support a
-2 return. Those lead to a linked bz in the commit message describing a
problem with multipath device with 'active' and 'ghost' devices. I'd
have to dig more on that to jiggle the memory.
Perhaps it's a path that needs a bit more code to more properly
determine details of the LUN returning -2... IOW: Something that would
dig on the failed device to see if it was mpath related.
John
Regards,
Jim
Index: libvirt-2.5.0/src/storage/storage_backend.c
===================================================================
--- libvirt-2.5.0.orig/src/storage/storage_backend.c
+++ libvirt-2.5.0/src/storage/storage_backend.c
@@ -1941,8 +1941,11 @@ virStorageBackendUpdateVolTargetInfo(vir
if (withBlockVolFormat) {
if ((ret = virStorageBackendDetectBlockVolFormatFD(target, fd,
- readflags))
< 0)
+ readflags))
< 0) {
+ if (ret == -2)
+ ret = 0;
goto cleanup;
+ }
}
cleanup: