[dm-devel] [RESEND RFC PATCH 00/32] separate operations from flags in the bio/request structs

[Bob Peterson]

----- Original Message -----
> This is just a resend of the patchset from earlier today. There was
> a error in the middle of sending the set, so it looks like 10 - 32 got
> dropped.
> 
> There are a couple new block layer commands we are trying to add support
> for in the near term:
> 
> compare and write
> http://www.spinics.net/lists/target-devel/msg07826.html
> 
> copy offload/extended copy/xcopy
> https://www.redhat.com/archives/dm-devel/2014-July/msg00070.html
> 
> The problem is if we contine to add more commands we will have to one day
> extend the cmd_flags/bi_rw fields again. To prevent that, this patchset
> separates the operation (REQ_WRITE, REQ_DISCARD, REQ_WRITE_SAME, etc) from
> the flags (REQ_SYNC, REQ_QUIET, etc) in the bio and request structs. In the
> end of this set, we will have two fields bio->bi_op/request->op and
> bio->bi_rw/request->cmd_flags.
> 
> The patches were made against Jens's linux-block tree's for-linus branch:
> https://git.kernel.org/cgit/linux/kernel/git/axboe/linux-block.git/log/?h=for-linus
> (last commit a22c4d7e34402ccdf3414f64c50365436eba7b93).
> 
> I have done some basic testing for a lot of the drivers and filesystems,
> but I wanted to get comments before trying to track down more hardware/
> systems for testing.
> 
> 
> Known issues:
> - REQ_FLUSH is still a flag, but should probably be a operation.
>  For lower level drivers like SCSI where we only get a flush, it makes
> more sense to be a operation. However, upper layers like filesystems
> can send down flushes with writes, so it is more of a flag for them.
> I am still working on this.
> 
> - There is a regression with the dm flakey target. It currently
> cannot corrupt the operation values.
> 
> - The patchset is a little awkward. It touches so much code,
> but I wanted to maintain git bisectibility, so there is lots of compat code
> left around until the last patches where everyting is cleaned up.

Hi Mike,

The GFS2 patches in patches 11, 14, 16 and 23 all look correct.
You can add my:
Reviewed-by: Bob Peterson <rpeterso at redhat.com>
to those, but I have not reviewed the non-GFS2 bits.

Regards,

Bob Peterson
Red Hat File Systems