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    SubjectRe: [ANNOUNCE]: ConfigFS enabled Generic Target Mode and iSCSI Target Stack on v2.6.27-rc7
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    On Thu, 2008-10-02 at 14:29 -0700, 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.
    >
    > I will be implementing this model over the next days.. I will post the
    > commit once its up and you can have a look..
    >

    Ok, here is the commit diff for adding Initiator ACLS to
    iscsi/$IQN/$TPGT/ under the acls/ subdirectory (instead of "initiators"
    in the example above).

    http://git.kernel.org/?p=linux/kernel/git/nab/lio-core-2.6.git;a=commitdiff;h=0a451affbe236b5538e5de06242372715e3ac52c;hp=374e8ace84ca58490be22d881f017d48c6742b50

    Other than the name change, everything is functioning in the commit as
    described in the example above. I am able to successfully mkdir(2) and
    rmdir(2) iscsi/$IQN/$TPGT/acls/$INITIATOR_IQN, as well as create the
    SymLinks from iscsi/$IQN/$TPGT/lun/lun_* to
    iscsi/$IQN/$TPGT/acls/$INITIATOR_IQN/lun_* to create the Initiator TPGT
    LUN Mappings.

    There are a couple of remaining items that I am still working on WRT the
    Initiator ACL code. One is that the CmdSN Queue Depth for the Initiator
    is hardcoded. This needs to be a configfs attribute under
    iscsi/$IQN/$TPGT/acls/$INITIATOR_NAME/, and then enabled with a
    attribute under the same $INITIATOR_NAME directory. Another is
    assigning READ-ONLY (its hardcoded to R/W for now) access to one of the
    initiator's TPG LUN mappings. I was thinking name in the TPG LUN
    Symlink destination name, we could include "lun_0:RO" in order to make
    this Initiator's LUN be READ-ONLY.

    Anyways, this are pretty minor and I should be commiting the remaining
    pieces over the weekend.

    --nab



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