On Thu, 2012-01-05 at 21:08 -0700, Dax Kelson wrote:
> To distill my previous email:
>
> [OK] # lsscsi
> [7:0:0:0] disk LIO-ORG IBLOCK 4.0 /dev/sdf
> [OK] # sg_turs /dev/sdf
> [OK] # sg_persist -n -o -I -S aa230003 -d /dev/sdf
> [FAIL] # sg_persist -n -i -r -d /dev/sdf
>
> Why the failure?
>
> iSCSI initiator is RHEL6.2 (iscsi-initiator-utils-6.2.0.872-10.el6)
> iSCSI target is Fedora16 (kernel 3.1.6 , targetcli-2.0rc1.fb3-2)
>
Hi Dax,
The problem is with the >= v3.0 (TCM v4.1) conversion to use
scatterlists instead of a contiguous buffer for all control CDBs, and
limiting allocation lengths to PAGE_SIZE is what is causing the problem
you've encountered.
By default sg_persist is using a 8192 byte allocation length, and is
hitting the following code from
target_core_transport.c:transport_generic_cmd_sequencer():
/* Let's limit control cdbs to a page, for simplicity's sake. */
if ((cmd->se_cmd_flags & SCF_SCSI_CONTROL_SG_IO_CDB) &&
size > PAGE_SIZE)
goto out_invalid_cdb_field;
A simple sg_persist work-around is to reduce the allocation length to
sub PAGE_SIZE like so using '-l 512':
# sg_persist -vv -i -s -l 512 -d /dev/sdd
open /dev/sdd with flags=0x800
inquiry cdb: 12 00 00 00 24 00
LIO-ORG IBLOCK 4.0
Peripheral device type: disk
open /dev/sdd with flags=0x802
Persistent Reservation In cmd: 5e 03 00 00 00 00 00 05 12 00
PR generation=0x1
Key=0xaa230003
All target ports bit clear
Relative port address: 0x3
not reservation holder
Transport Id of initiator:
SAS address: 0x6001405185b68800
So aside from a work-around here, I'll have to think a bit more about
how to properly address this in TCM v4.1 code in lio-core.git and
mainline. I'm still catching up on a number of items, so this will take
a few days.
Thanks,
--nab
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