[Xen-devel] [PATCH] v3 - Add exclusive locking option to block-iscsi

[Steven Haigh <netwiz@xxxxxxxxx>]

On 2016-05-05 15:52, Steven Haigh wrote:
> On 2016-05-05 12:32, Steven Haigh wrote:
> > Overview
> >
> > If you're using iSCSI, you can mount a target by multiple Dom0
> > machines on the same target. For non-cluster aware filesystems, this
> > can lead to disk corruption and general bad times by all. The iSCSI
> > protocol allows the use of persistent reservations as per the SCSI
> > disk spec. Low level SCSI commands for locking are handled by the
> > sg_persist program (bundled with sg3_utils package in EL).
> >
> > The aim of this patch is to create a 'locktarget=y' option specified
> > within the disk 'target' command for iSCSI to lock the target in
> > exclusive mode on VM start with a key generated from the local systems
> > IP, and release this lock on the shutdown of the DomU.
> >
> > Example Config:
> > disk            =
> > ['script=block-iscsi,vdev=xvda,target=iqn=iqn.1986-03.com.sun:02:mytarget,portal=iscsi.example.com,locktarget=y']
> >
> > In writing this, I have also re-factored parts of the script to put
> > some things in what I believe to be a better place to make expansion
> > easier. This is mainly in removing functions that purely call other
> > functions with no actual code execution.
> >
> > Signed-off-by: Steven Haigh <netwiz@xxxxxxxxx>
> >
> > (on a side note, first time I've submitted a patch to the list and I'm
> > currently stuck on a webmail client, so apologies in advance if this
> > all goes wrong ;)
> Changes in v2:
> Bugfix: Call find_device to locate the /dev/sdX component of the iSCSI
> target before trying to run unlock_device().
>
> Apologies for this oversight.
Changes in v3:
* Split the block-iscsi cleanup into a seperate patch 
(block-iscsi-locking-v3_01_simplify_block-iscsi.patch).
* Add locking in second patch file 
(block-iscsi-locking-v3_02_add_locking.patch)
--
Steven Haigh

Email: netwiz@xxxxxxxxx
Web: https://www.crc.id.au
Phone: (03) 9001 6090 - 0412 935 897

Attachment: block-iscsi-locking-v3_01_simplify_block-iscsi.patch
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Attachment: block-iscsi-locking-v3_02_add_locking.patch
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