Hi all,
I am trying out Linux SCSI Target and it seems that the way persistent
reservations are handled does not conform with SPC-4.
SPC4r17 (5.7.10) states that:
The persistent reservation holder is determined by the type of the
persistent reservation as follows:
a) For a persistent reservation of the type Write Exclusive – All
Registrants or Exclusive Access – All Registrants, the persistent
reservation holder is any registered I_T nexus;
While Table 51 states that:
'Write Exclusive – All Registrants' or 'Exclusive Access – All
Registrants' reservations shall be released when the registration
for the last registered I_T nexus is removed or when the type or
scope is changed.
This doesn't seem to be the case with Linux SCSI Target. More
particularly, I have set up an iSCSI target, using the Linux SCSI Target
implementation, and I am connecting to it through two different VMs
using the open-iscsi project.
root@node1:~# sg_inq /dev/sda
standard INQUIRY:
PQual=0 Device_type=0 RMB=0 version=0x05 [SPC-3]
[AERC=0] [TrmTsk=0] NormACA=0 HiSUP=0 Resp_data_format=2
SCCS=1 ACC=0 TPGS=3 3PC=1 Protect=0 BQue=0
EncServ=0 MultiP=0 [MChngr=0] [ACKREQQ=0] Addr16=0
[RelAdr=0] WBus16=0 Sync=0 Linked=0 [TranDis=0] CmdQue=1
length=36 (0x24) Peripheral device type: disk
Vendor identification: LIO-ORG
Product identification: FILEIO
Product revision level: 4.0
Unit serial number: 9efc01f5-429d-42be-b507-9dc4439f511d
root@node2:~# sg_inq /dev/sda
standard INQUIRY:
PQual=0 Device_type=0 RMB=0 version=0x05 [SPC-3]
[AERC=0] [TrmTsk=0] NormACA=0 HiSUP=0 Resp_data_format=2
SCCS=1 ACC=0 TPGS=3 3PC=1 Protect=0 BQue=0
EncServ=0 MultiP=0 [MChngr=0] [ACKREQQ=0] Addr16=0
[RelAdr=0] WBus16=0 Sync=0 Linked=0 [TranDis=0] CmdQue=1
length=36 (0x24) Peripheral device type: disk
Vendor identification: LIO-ORG
Product identification: FILEIO
Product revision level: 4.0
Unit serial number: 9efc01f5-429d-42be-b507-9dc4439f511d
I register both of the IT_nexuses with the target.
root@node1:~# sg_persist --out --register --param-sark 0x1 /dev/sda
root@node2:~# sg_persist --out --register --param-sark 0x2 /dev/sda
root@node1:~# sg_persist --in --read-full-status /dev/sda
LIO-ORG FILEIO 4.0
Peripheral device type: disk
PR generation=0x2
Key=0x1
All target ports bit clear
Relative port address: 0x1
not reservation holder
Transport Id of initiator:
iSCSI name and session id: iqn.1993-08.org.debian:01:node1
Key=0x2
All target ports bit clear
Relative port address: 0x1
not reservation holder
Transport Id of initiator:
iSCSI name and session id: iqn.1993-08.org.debian:01:node2
Then I get a persistent reservation with type 'Exclusive Access - All
Registrants' for node1.
root@node1:~# sg_persist --out --reserve --prout-type=8 --param-rk=0x1 /dev/sda
root@node1:~# sg_persist --in --read-full-status /dev/sda
LIO-ORG FILEIO 4.0
Peripheral device type: disk
PR generation=0x2
Key=0x1
All target ports bit clear
Relative port address: 0x1
<< Reservation holder >>
scope: LU_SCOPE, type: Exclusive Access, all registrants
Transport Id of initiator:
iSCSI name and session id: iqn.1993-08.org.debian:01:node1
Key=0x2
All target ports bit clear
Relative port address: 0x1
not reservation holder
Transport Id of initiator:
iSCSI name and session id: iqn.1993-08.org.debian:01:node2
The node2 is listed as "not reservation holder".
Shouldn't node2 be displayed as a Reservation holder since the
persistent reservation is of type 'Exclusive Access, all registrants'?
If I then proceed to unregister node1, the reservation gets released
altogether. Shouldn't the reservation remain, until the last registered
I_T nexus goes away? I think this violates SPC-4, please see the excerpt
above.
root@node1:~# sg_persist --out --register --param-rk=0x1 --param-sark=0x0 /dev/sda
root@node1:~# sg_persist --in --read-full-status /dev/sda
LIO-ORG FILEIO 4.0
Peripheral device type: disk
PR generation=0x2
Key=0x2
All target ports bit clear
Relative port address: 0x1
not reservation holder
Transport Id of initiator:
iSCSI name and session id: iqn.1993-08.org.debian:01:node2
root@node2:~# sg_persist --in --read-reservation /dev/sda
LIO-ORG FILEIO 4.0
Peripheral device type: disk
PR generation=0x2, there is NO reservation held
Is this a bug or am I missing something?
Ilias
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