Re: [ANNOUNCE]: ConfigFS enabled Generic Target Mode and iSCSI TargetStack on v2.6.27-rc7
From: Vladislav Bolkhovitin
Date: Tue Oct 07 2008 - 05:57:24 EST
Nicholas A. Bellinger wrote:
On Thu, 2008-10-02 at 21:00 +0400, Vladislav Bolkhovitin wrote:
Nicholas A. Bellinger wrote:
# Add some more HBA and storage Objects
target:~# mkdir -p $TARGET/fileio_0/file_object
target:~# mkdir -p $TARGET/rd_mcp_0/ramdisk0
target:~# mkdir -p $TARGET/rd_dr_0/ramdisk0
target:~# mkdir -p $TARGET/pscsi_0/sdd
target:~# echo scsi_channel_id=0,scsi_target_id=3,scsi_lun_id=0 > $TARGET/pscsi_0/sdd/dev_control
target:~# echo 1 > $TARGET/pscsi_0/sdd/dev_enable
# Now, create LUN 1 and another Port Symlink to a new device on the same $IQN/tpgt_1
mkdir -p "$FABRIC/$DEF_IQN/tpgt_1/lun/lun_1"
# Create the iSCSI Target Port Mapping for $DEF_IN/tpgt_1 LUN 1
# to lvm_test0 and give it the port symbolic name of lio_east_port
ln -s $TARGET/pscsi_0/sdd/ "$FABRIC/$DEF_IQN/tpgt_1/lun/lun_1/lio_east_port"
target:~# tree $CONFIGFS
/sys/kernel/config/
`-- target
|-- core
| |-- fileio_0
| | |-- file_object
| | | |-- dev_control
| | | |-- dev_enable
| | | `-- dev_info
| | `-- hba_info
| |-- iblock_0
| | |-- hba_info
| | `-- lvm_test0
| | |-- dev_control
| | |-- dev_enable
| | `-- dev_info
| |-- pscsi_0
| | |-- hba_info
| | `-- sdd
| | |-- dev_control
| | |-- dev_enable
| | `-- dev_info
| |-- rd_dr_0
| | |-- hba_info
| | `-- ramdisk0
| | |-- dev_control
| | |-- dev_enable
| | `-- dev_info
| `-- rd_mcp_0
| |-- hba_info
| `-- ramdisk0
| |-- dev_control
| |-- dev_enable
| `-- dev_info
|-- iscsi
| |-- iqn.2003-01.org.linux-iscsi.target.i686:sn.e475ed6fcdd0
| | `-- tpgt_1
| | |-- lun
| | | |-- lun_0
| | | | |-- lio_west_port -> ../../../../../../target/core/iblock_0/lvm_test0
| | | | |-- port_control
| | | | `-- port_info
| | | `-- lun_1
| | | |-- lio_east_port -> ../../../../../../target/core/pscsi_0/sdd
| | | |-- port_control
| | | `-- port_info
| | |-- np
| | | `-- 172.16.201.137:3260
| | | `-- portal_info
| | |-- tpg_control
| | `-- tpg_enable
| `-- lio_version
`-- version
22 directories, 29 files
It's good, I like it. The only thing concerns me that, considering how
much time *I* spent to understand it, for an average user understanding
it can be an unbearable nightmare ;)
Well, the idea is not necessarily making the configfs interface the
easiest to use in the world by user directly through $CONFIGFS, but to
make the CLI scripts that speak $CONFIGFS/target CLI, and of course the
actual UIs for user that interact with generic target core and
$FABRIC_MODs be as simple and elegent as possible.
That is what I believe the balance that a configfs enabled generic
target core provides to both the $CONFIGFS/target API and to $FABRIC_MOD
maintainers looking to port their code to use a generic control
infrastructure. :-)
In a few days I'll write a proposed configfs hierarchy for existing SCST
/proc interface.
Sounds good! Please let me know if you have questions.
There's one unsolved problem. As I've already written, SCST core needs
an ability to provide to user space a large amount of data, which may
not fit to a single page.
A list of connected initiators ("sessions"
file in /proc), for instance. Each initiator in that list has a number
of attributes: initiator name, target template name, count of
outstanding commands, etc. The logical way for that would be to create a
subdirectory for each initiator, like:
/sys/kernel/config/
`-- target
`-- sessions
`-- session1
| |-- initiator_name
| |-- template_name
| `-- commands
|
`-- session2
|-- initiator_name
`-- template_name
`-- commands
The the Initiator Port ACLs need to go
under /sys/kernel/config/target/$FABRIC because the struct fabric_acl *
will always contain fabric dependent config items. For example, Since
these struct fabric_acl_t do *NOT* symlink directly back to
target_core_mod under /sys/kernel/config/target/core/$HBA/$DEV, but to
fabric_lun_t (iscsi_lun_t in my case) to Symlink to
a /sys/kernel/config/target/core/$HBA/$DEV that has been registered with
the generic target configfs infrastructure.
Here is what I am thinking wrt /sys/kernel/config/target/iscsi and iSCSI
Initiator Node ACLs to iSCSI Portal Groups and iSCSI LUNs attached to
those Portal Groups. There are two cases:
*) The production case with with user creating those ACLs under $FABRIC
(which is what I will focus on now).
* And "Demo Mode" case where any Initiator logging into
$FABRIC/$ENDPOINT/$PORTAL can have access to all
$FABRIC/$ENDPOINT/lun/lun_*/*my_ports*
The production ACL case would look like:
export CONFIGFS=/sys/kernel/config/
export TARGET=/sys/kernel/config/target/core/
export FABRIC=/sys/kernel/config/target/iscsi/
TARGET_IQN=iqn.2003-01.org.linux-iscsi.ps3-cell.ppc64:sn.f8f651bd5fec
INITIATOR_IQN=iqn.1993-08.org.debian:01.f82074ca555f
<Setup $STORAGE_OBJECTs under $TARGET>
# Create the LIO-target endpoint
mkdir -p "$FABRIC/$TARGET_IQN/tpgt_1/np/172.16.201.137:3260"
mkdir -p "$FABRIC/$TARGET_IQN/tpgt_1/lun/lun_0"
<Setup Port Symlinks from $TARGET to $TARGET_IQN/tpgt_1/lun/lun_0>
# Create the Initiator ACL under $TARGET_IQN/tpgt_1
mkdir -p $"FABRIC/$TARGET_IQN/tpgt_1/initiators/$INITIATOR_IQN"
# Allow $INITIATOR_IQN access to tpgt_1/lun/lun_0/
ln -s "$FABRIC/$TARGET_IQN/tpgt_1/lun/lun_0" \
"$FABRIC/$TARGET_IQN/tpgt_1/initiators/$INITIATOR_IQN/lun_0"
From there, you don't have to worry about PAGE_SIZE limitiations w/o, I
can simply use use:
cat $FABRIC/iqn*/tpgt*/initiators/*/session
to see which acl'ed iSCSI Initiators are logged in on all iSCSI Target
Ports.
Also I should add that I am currently using /proc/scsi_target/mib
and /proc/iscsi_target_mib for READ-ONLY data with target_core_mod.ko
and iscsi_target_mod.ko respectively. For the other "Demo Mode" case
mentioned above, I am currently using /proc/iscsi_target/mib/sess_attr
to see the active sessions for LIO-Target.
Sorry for the delay. I didn't have a chance to look at it sufficiently
close.
Basically the idea about how to manage ACLs is good, but I don't like,
that with it *ALL* the target drivers would have to implement the
necessary code. It shouldn't be so, management of all security stuff
should be purely duty of the mid-layer. And this is exactly implemented
in SCST. All what target drivers should do with it is to pass target's
name on its registration in scst_register() and then while registering a
session with remote initiator using scst_register_session() pass to it
the initiator's name. Everything else is done by the SCST core.
Thus, I believe, all the ACL management should be done not in $FABRIC/,
but in $TARGET/. It would remove all the corresponding configfs
headaches from the target drivers writers.
But, in fact, I asked about completely different thing. SCSI target
mid-layer in some cases needs to export in user space amount of data,
which doesn't fit one page. /proc/scsi_tgt/sessions is one example. What
should we do for it?
I will be implementing this model over the next days.. I will post the
commit once its up and you can have a look..
--nab
But looks like configfs requires each subdirectory to be created
manually by user via, e.g., mkdir command. It would be really strange if
we require user to manually create "sessions" subdirectory to be able to
see a list of connected initiators. Do I miss anything?
Vlad
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/