[PATCH 0/4]: Add ALUA primary/secondary access state/status metadata support

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

Greeting SCSI and multipath folks,

This patch series to TCM/LIO v3.1 kernel code in lio-core-2.6.git adds support for struct file ALUA metadata
of primary/secondary access state/status to /var/target/alua/, which allows the ALUA metadata to be loaded
into configfs attributes at TCM + fabric bringup time to reinstate the last saved ALUA metadata across target
power loss, reboots, et al.

Here is what an example running layout of metadata in /var/target/alua looks like:

    target:/mnt/sdb/lio-core-2.6.git# tree /var/target/alua/
    /var/target/alua/
    |-- iSCSI  # These are for fabric dependent Port/LUN ALUA secondary access metadata
    |   |-- iqn.2003-01.org.linux-iscsi.target.i686:sn.cff3eedbd2fd+1
    |   |   `-- lun_0
    |   `-- iqn.2003-01.org.linux-iscsi.target.i686:sn.e475ed6fcdd0+1
    |       `-- lun_0
    |  # These are for TCM storage object target port group ALUA primary access metadata
    |-- tpgs_41ee70ff-4fbe-4fb8-a690-b3c65639db10
    |-- tpgs_96eb8120-f0fc-40ce-b673-8ac302aa6b4e
    `-- tpgs_a97e4ce21c0711de829b000c2943d57b
        |-- lio_alua_east
        `-- lio_alua_west

This patch series includes new EXPORT_SYMBOL() calls to target_core_alua.c that add generic configfs
store/show handlers for fabric dependent configfs attribute code, as well as the modification to
LIO-Target/ConfigFS to use these generic handlers.  Also, code has been added for calling filp_open() ->
vfs_writev() -> flip_close() for updating the actual struct file in both primary/secondary access state
transitions for both explict (via MO SET_TARGET_PORT_GROUPS) and implict (via configfs) ALUA operations.

[PATCH 1/4] [Target_Core_Mod/ALUA]: Add support for saving primary port metadata across target power loss
[PATCH 2/4] [Target_Core_Mod/ALUA]: Add support for saving secondary fabric port metadata across target power loss
[PATCH 3/4] [Target_Core_Mod]: Add alua mutex initialization in core_alloc_port()
[PATCH 4/4] [LIO-Target/ConfigFS]: Add ALUA secondary access state attributes for saving/reading metadata

 drivers/lio-core/iscsi_target_configfs.c |   54 +++++++
 drivers/target/target_core_alua.c        |  232 +++++++++++++++++++++++++++++-
 drivers/target/target_core_configfs.c    |   75 ++++++++++-
 drivers/target/target_core_device.c      |    1 +
 include/target/target_core_alua.h        |   17 ++-
 include/target/target_core_base.h        |    7 +
 6 files changed, 378 insertions(+), 8 deletions(-)

The userspace commits to make it all go can be found here:

http://git.kernel.org/?p=linux/storage/lio/lio-utils.git;a=commitdiff;h=3dbe22aa3941dbf0126490e95e50a2f536721f3e
http://git.kernel.org/?p=linux/storage/lio/lio-utils.git;a=commitdiff;h=494e2f6d1163227602d2336cd65d57bf2cf07e78
http://git.kernel.org/?p=linux/storage/lio/lio-utils.git;a=commitdiff;h=e632383be4ac3634325551b8fbc152bb2d2f5fc2
http://git.kernel.org/?p=linux/storage/lio/lio-utils.git;a=commitdiff;h=4917f200458845468db33b6abd30c1a0cc64fbba
http://git.kernel.org/?p=linux/storage/lio/lio-utils.git;a=commitdiff;h=c0d26101ee33aaf284b7b86391cf7c70c9859816
http://git.kernel.org/?p=linux/storage/lio/lio-utils.git;a=commitdiff;h=fa48c904073a878b36e0b92eda28faebea55aafc

Any comments or questions are welcome!

--nab