Re: [ANNOUNCE]: ConfigFS enabled Generic Target Mode and iSCSI Target Stack on v2.6.27-rc7

["Nicholas A. Bellinger" <nab@linux-iscsi.org>]

On Wed, 2008-10-01 at 21:36 +0400, Vladislav Bolkhovitin wrote:
> Hi Nicholas,
> 
> Nicholas A. Bellinger wrote:
> > Greetings all,
> > 
> > I am happy to announce that the first ConfigFS configurable generic
> > target engine (target_core_mod) and iSCSI Target Stack
> > (iscsi_target_mod) are now able to use ConfigFS symlinks for the
> > creation of Linux Storage Objects from drivers/scsi, block, or fs/
> > storage objects to iSCSI Target Port Endpoints.
> > 
> > The code is available currently running on v2.6.27-rc7 and has been
> > broken up into a number of commits at:
> > http://git.kernel.org/?p=linux/kernel/git/nab/lio-core-2.6.git;a=summary
> > 
> > Now that the primary configfs functionality is up and allowing iSCSI
> > Initiator Traffic to the symlinked storage objects from a generic target
> > engine, I will be continuing work on the complete logic for configfs
> > enabled iscsi_target_mod, as well as removing the legacy IOCTL control
> > path as equivalent functionality is added with ConfigFS.  
> > 
> > Also, one of the next major steps for the upstream generic target engine
> > and iSCSI target stack is to include SCST's target mode API between
> > Engine / Fabric to give target_core_mod a proper Fabric API to allow
> > other SCST fabric modules to access target_core_mod's configfs enabled
> > storage objects.  Also, allowing STGT to use the configfs interface to
> > allow for userspace fabrics to the same target_core_mod storage objects
> > is also on the list, but I imagine interest from those communities will
> > certainly help drive those efforts.  
> > 
> > Here are the shell variables required to make it all go:
> > 
> > export CONFIGFS=/sys/kernel/config/
> > export TARGET=/sys/kernel/config/target/core/
> > export FABRIC=/sys/kernel/config/target/iscsi/
> > 
> > The storage objects registered with target_core_mod via $TARGET may be
> > mapped from $TARGET/$HBA/$STORAGE_OBJECT any number of times to:
> > 
> > $FABRIC/$IQN/tpgt_1/lun/lun_0/$PORT_LINK
> > $FABRIC/$IQN/tpgt_1/lun/lun_1/$PORT_LINK
> > $FABRIC/$IQN/tpgt_2/lun/lun_0/$PORT_LINK
> > $FABRIC/$ANOTHER_IQN/tpgt_1/lun_0/$PORT_LINK
> > ....
> > ....
> > 
> > Here are the shell commands to bring storage objects online..
> > 
> > # Create a IBLOCK HBA and virtual storage object
> > mkdir -p $TARGET/iblock_0/lvm_test0
> > # Tell the virtual storage object what struct block_device we want
> > echo iblock_major=254,iblock_minor=2 > $TARGET/iblock_0/lvm_test0/dev_control
> > # Enable the virtual storage object and call bd_claim()
> > echo 1 > $TARGET/iblock_0/lvm_test0/dev_enable
> > 
> > DEF_IQN="iqn.2003-01.org.linux-iscsi.target.i686:sn.e475ed6fcdd0"
> > 
> > # Create the network portal on $DEF_IQN/tpgt_1
> > mkdir -p "$FABRIC/$DEF_IQN/tpgt_1/np/172.16.201.137:3260"
> > # Create LUN 0 on $DEF_IQN/tpgt_1
> > mkdir -p "$FABRIC/$DEF_IQN/tpgt_1/lun/lun_0"
> > # Create the iSCSI Target Port Mapping for $DEF_IN/tpgt_1 LUN 0
> > # to lvm_test0 and give it the port symbolic name of lio_west_port
> > ln -s $TARGET/iblock_0/lvm_test0 "$FABRIC/$DEF_IQN/tpgt_1/lun/lun_0/lio_west_port"
> > 
> > # Allow iSCSI Initiators to login to $DEF_IQN/tpgt_1
> > #warning Currently uses generate_node_acls=1,cache_dynamic_acls=1,demo_mode_lun_access=1
> > echo 1 > $FABRIC/$DEF_IQN/tpgt_1/tpg_enable
> > 
> > target:~# tree $CONFIGFS
> > /sys/kernel/config/
> > `-- target
> >     |-- core
> >     |   `-- iblock_0
> >     |       |-- hba_info
> >     |       `-- lvm_test0
> >     |           |-- 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
> >     |   |       |-- np
> >     |   |       |   `-- 172.16.201.137:3260
> >     |   |       |       `-- portal_info
> >     |   |       |-- tpg_control
> >     |   |       `-- tpg_enable
> >     |   `-- lio_version
> >     `-- version
> > 
> > 
> > ----------------------------------------------------------
> > 
> > # 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.

--nab

> Vlad
> 
> 
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