Re: [PATCH 8/9] target: Add support for COMPARE_AND_WRITE emulation

2013-08-21 Thread Nicholas A. Bellinger
On Wed, 2013-08-21 at 09:14 -0700, Christoph Hellwig wrote: > I don't like the layering here. The re-execution of the same command > for both reading and writing the data from/to the backend device already > looks sketchy here due to doubling work of task attribute handling, the > various state bi

Re: [PATCH 8/9] target: Add support for COMPARE_AND_WRITE emulation

2013-08-21 Thread Christoph Hellwig
I don't like the layering here. The re-execution of the same command for both reading and writing the data from/to the backend device already looks sketchy here due to doubling work of task attribute handling, the various state bits, etc. And it will only get more complicated when the required lo

[PATCH 8/9] target: Add support for COMPARE_AND_WRITE emulation

2013-08-20 Thread Nicholas A. Bellinger
From: Nicholas Bellinger This patch adds support for COMPARE_AND_WRITE emulation on a per block basis. This logic is used as an atomic test and set primative currently used by VMWare ESX VAAI for performing array side locking of individual VMFS extent ownership. This includes the COMPARE_AND_WR