Re: [PATCH v9 00/25] RTRS (former IBTRS) RDMA Transport Library and RNBD (former IBNBD) RDMA Network Block Device

[Leon Romanovsky <leon@kernel.org>]

On Fri, Feb 21, 2020 at 11:46:56AM +0100, Jack Wang wrote:
> Hi all,
>
> Here is v9 of  the RTRS (former IBTRS) RDMA Transport Library and the
> corresponding RNBD (former IBNBD) RDMA Network Block Device, which includes
> changes to address comments from the community.
>
> Introduction
> -------------
>
> RTRS (RDMA Transport) is a reliable high speed transport library
> which allows for establishing connection between client and server
> machines via RDMA. It is based on RDMA-CM, so expect also to support RoCE
> and iWARP, but we mainly tested in IB environment. It is optimized to
> transfer (read/write) IO blocks in the sense that it follows the BIO
> semantics of providing the possibility to either write data from a
> scatter-gather list to the remote side or to request ("read") data
> transfer from the remote side into a given set of buffers.
>
> RTRS is multipath capable and provides I/O fail-over and load-balancing
> functionality, i.e. in RTRS terminology, an RTRS path is a set of RDMA
> connections and particular path is selected according to the load-balancing
> policy. It can be used for other components beside RNBD.
>
> Module parameter always_invalidate is introduced for the security problem
> discussed in LPC RDMA MC 2019. When always_invalidate=Y, on the server side we
> invalidate each rdma buffer before we hand it over to RNBD server and
> then pass it to the block layer. A new rkey is generated and registered for the
> buffer after it returns back from the block layer and RNBD server.
> The new rkey is sent back to the client along with the IO result.
> The procedure is the default behaviour of the driver. This invalidation and
> registration on each IO causes performance drop of up to 20%. A user of the
> driver may choose to load the modules with this mechanism switched off
> (always_invalidate=N), if he understands and can take the risk of a malicious
> client being able to corrupt memory of a server it is connected to. This might
> be a reasonable option in a scenario where all the clients and all the servers
> are located within a secure datacenter.
>
> RNBD (RDMA Network Block Device) is a pair of kernel modules
> (client and server) that allow for remote access of a block device on
> the server over RTRS protocol. After being mapped, the remote block
> devices can be accessed on the client side as local block devices.
> Internally RNBD uses RTRS as an RDMA transport library.
>
> Commits for kernel can be found here:
>    https://github.com/ionos-enterprise/ibnbd/commits/linux-5.6-rc2-ibnbd-v9
>
> Testing
> -------
>
> All the changes have been tested with our regression testsuite in our staging environment
> in IONOS data center. it's around 200 testcases, for both always_invalidate=N and
> always_invalidate=Y configurations.
>
> Changelog
> ---------
> v9:
>  o Rebased to linux-5.6-rc2
>  o Update Date/Kernel version in Documentation
>  o Update description in Kconfig for RNBD
>  o rtrs-clt: inline rtrs_clt_decrease_inflight
>  o rtrs-clt: only track inflight for Min_inflight policy
> v8:
>  o Rebased to linux-5.5-rc7
>  o Reviewed likey/unlikely usage, only keep the one in IO path suggested by Leon Romanovsky
>  o Reviewed inline usage, remove inline for functions longer than 5 lines of code suggested by Leon
>  o Removed 2 WARN_ON suggested by Leon
>  o Removed 2 empty lines between copyright suggested by Leon
>  o Makefile: remove compat include for upstream suggested by Leon
>  o rtrs-clt: remove module parameters suggested by Leon
>  o drop rnbd_clt_dev_is_mapped
>  o rnbd-clt: clean up rnbd_rerun_if_needed
>  o rtrs-srv: remove reset_all sysfs
>  o rtrs stats: remove wc_completion stats
>  o rtrs-clt: enhance doc for rtrs_clt_change_state
>  o rtrs-clt: remove unused rtrs_permit_from_pdu
>  * https://lore.kernel.org/linux-block/20200124204753.13154-1-jinpuwang@gmail.com/
> v7:
>  o Rebased to linux-5.5-rc6
>  o Implement code-style/readability/API/Documentation etc suggestions by Bart van Assche
>  o Make W=1 clean
>  o New benchmark results for Mellanox ConnectX-5
>  o second try adding MAINTAINERS entries in alphabetical order as Gal Pressman suggested
>  * https://lore.kernel.org/linux-block/20200116125915.14815-1-jinpuwang@gmail.com/
> v6:
>   o Rebased to linux-5.5-rc4
>   o Fix typo in my email address in first patch
>   o Cleanup copyright as suggested by Leon Romanovsky
>   o Remove 2 redudant kobject_del in error path as suggested by Leon Romanovsky
>   o Add MAINTAINERS entries in alphabetical order as Gal Pressman suggested
>   * https://lore.kernel.org/linux-block/20191230102942.18395-1-jinpuwang@gmail.com/
> v5:
>   o Fix the security problem pointed out by Jason
>   o Implement code-style/readability/API/etc suggestions by Bart van Assche
>   o Rename IBTRS and IBNBD to RTRS and RNBD accordingly
>   o Fileio mode support in rnbd-srv has been removed.
>   * https://lore.kernel.org/linux-block/20191220155109.8959-1-jinpuwang@gmail.com/
> v4:
>   o Protocol extended to transport IO priorities
>   o Support for Mellanox ConnectX-4/X-5
>   o Minor sysfs extentions (display access mode on server side)
>   o Bug fixes: cleaning up sysfs folders, race on deallocation of resources
>   o Style fixes
>   * https://lore.kernel.org/linux-block/20190620150337.7847-1-jinpuwang@gmail.com/
> v3:
>   o Sparse fixes:
>      - le32 -> le16 conversion
>      - pcpu and RCU wrong declaration
>      - sysfs: dynamically alloc array of sockaddr structures to reduce
> 	   size of a stack frame
>   o Rename sysfs folder on client and server sides to show source and
>     destination addresses of the connection, i.e.:
> 	   .../<session-name>/paths/<src@dst>/
>   o Remove external inclusions from Makefiles.
>   * https://lore.kernel.org/linux-block/20180606152515.25807-1-roman.penyaev@profitbricks.com/
> v2:
>   o IBNBD:
>      - No legacy request IO mode, only MQ is left.
>   o IBTRS:
>      - No FMR registration, only FR is left.
>   * https://lore.kernel.org/linux-block/20180518130413.16997-1-roman.penyaev@profitbricks.com/
> v1:
>   o IBTRS: load-balancing and IO fail-over using multipath features were added.
>   o Major parts of the code were rewritten, simplified and overall code
>     size was reduced by a quarter.
>   * https://lore.kernel.org/linux-block/20180202140904.2017-1-roman.penyaev@profitbricks.com/
> v0:
>   o Initial submission
>   * https://lore.kernel.org/linux-block/1490352343-20075-1-git-send-email-jinpu.wangl@profitbricks.com/
>
> As always, please review and share your comments, and consider to merge to
> upstream.
>
> Thanks.
>

I still see module parameters and prints after allocation failures.

Thanks