RE: [RFC PATCH 0/19] A kernel-level configfs enabled generic target engine for Linux v2.6.32

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

On Mon, 2009-09-14 at 13:12 -0700, Chetan.Loke@Emulex.Com wrote:
> > -----Original Message-----
> > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
> > owner@vger.kernel.org] On Behalf Of Nicholas A. Bellinger
> > Sent: Friday, September 11, 2009 9:55 PM
> > To: LKML; linux-scsi
> > Cc: Andrew Morton; Greg KH; Douglas Gilbert; James Bottomley; Hannes
> > Reinecke; FUJITA Tomonori; Mike Christie; Joel Becker; Martin K. Petersen;
> > Christoph Hellwig; Linus Torvalds; Alan Stern; Boaz Harrosh; Florian Haas;
> > Philipp Reisner
> > Subject: [RFC PATCH 0/19] A kernel-level configfs enabled generic target
> > engine for Linux v2.6.32
> > 
> > Greetings all,
> > 
> > This is my humble request for review and inclusion of
> > Target_Core_Mod/ConfigFS v3.2 from lio-core-2.6.git code into mainline
> > v2.6.32.  With TCM v3.2, the two major SPC-4 SCSI target mode fabric
> > features that have now been completed: Persistent Reservation APTPL and
> > implict/explict ALUA are the first all optional SPC4 defined feature
> > implementation of PR and ALUA in the Linux OSS target theatre using an
> > upstream user-driven virtual filesystem directory hierarchy structure
> > based on configfs that can be configured in realtime in combination with
> > interpreted userspace code.
> > 
> > Both of these new features are now being used to provide Persistent
> > Reservations
> > across target power loss and asymmetric multipath I/O to both Linux and
> > non-Linux
> > clients.  There is also an optional ALUA transition delay logic that has
> > been
> > included to futher debug and improve existing upstream client side Linux
> > kernel code
> > using TCM v3.2. These patches have been diffed against v2.6.31, and tested
> > on x86
> > 32-bit HVM, x86_64 KVM, and powerpc.
> > 
> > There is cleanup work continuing to make the TCM code to use dprintk(),
> > and some include cleanups, and other minor fixes.  The code has also
> > been run through checkpatch again since the posting in April, and all
> > errors have been removed, with the exception of one ConfigFS macro
> > define triggering a checkpatch false positive.
> > 
> > As with the posting of the TCM v3.0 code earlier in April, I have
> > decided to break up the submissions into the generic target_core_mod
> > piece (this patch series) and then a seperate one that will be appearing
> > in the next days for v3.2 of the LIO-Target iSCSI fabric module.
> > 
> > More Information about Target_Core_Mod/ConfigFS, and PR and ALUA:
> > 
> > http://www.linux-iscsi.org/index.php/Target_Core_Mod/ConfigFS
> > http://www.linux-iscsi.org/index.php/Persistent_Reservations
> > http://www.linux-iscsi.org/index.php/ALUA
> > 
> > The complete v3.x TCM CLI operations set can be found here:
> > 
> > http://www.linux-iscsi.org/index.php/Lio-utils#v3.1_TCM_CLI_operations
> > 
> > Instructions and examples for getting setup:
> > 
> > http://linux-iscsi.org/builds/docs/LIO-3.0-Users_Reference_Manual.pdf
> > http://www.linux-iscsi.org/index.php/Howto#Start_target_core_mod
> > 
> > Constructive comments are welcome,
> > 
> > --nab
> > 
> 
> 
> 
> Any pointers/URLs for the design/arch doc?

Greetings Chetan,

There are various bits and pieces detailing the TCM design on the
linux-iscsi.org wiki, but no definitive design document (aside from the
comments in the code) is available yet.  

I will however be putting together a first draft for this (along with
the user-level stuff) for Documentation/ soon.  Until then, I would be
happy to answer any questions you may have.

--nab 

> 
> 
> Chetan