ocf bdev

New virtual bdev module based on Open CAS Framework has been added.
This module allows for the use of one bdev to act as a high performance cache in front of another bdev.
Please see documentation for more details.
Only write through mode is currently supported and this feature is considered experimental.

event framework

For spdk_app_parse_args, add return value to the callback which parses application
specific command line parameters to protect SPDK applications from crashing by invalid
values from user input.

By default, all SPDK applications will now reserve all hugepages at runtime. The pre-reserved
memory size can be still set with -s or --mem-size option, although the default value
was reduced down to 0.

A custom hugetlbfs directory can now be specified via spdk_app_opts.
This can be used to configure hugepages with different sizes, a different size limit,
or different access permissions than the system's default hugepage pool.
SPDK applications can specify a custom hugetlbfs mount with the --huge-dir option.


spdk_vtophys() has been refactored to accept length of the translated region as a new
parameter. The function will now update that parameter with the largest possible value
for which the memory is contiguous in the physical memory address space.

The following functions were removed:

  • spdk_pci_nvme_device_attach()
  • spdk_pci_nvme_enumerate()
  • spdk_pci_ioat_device_attach()
  • spdk_pci_ioat_enumerate()
  • spdk_pci_virtio_device_attach()
  • spdk_pci_virtio_enumerate()

They were replaced with generic spdk_pci_device_attach() and spdk_pci_enumerate() which
require a new spdk_pci_driver object to be provided. It can be one of the following:

  • spdk_pci_nvme_get_driver()
  • spdk_pci_ioat_get_driver()
  • spdk_pci_virtio_get_driver()

spdk_pci_hook_device() and spdk_pci_unhook_device() were added. Those allow adding a virtual
spdk_pci_device into the SPDK PCI subsystem. A virtual device calls provided callbacks for
each BAR mapping request or PCI config access. It's attachable with spdk_pci_device_attach()
or spdk_pci_enumerate() like any other device.

A new spdk_pause() function was added to pause CPU execution for an implementation specific
amount of time. Quoting from DPDK function this is based on: "This call is intended for
tight loops which poll a shared resource or wait for an event. A short pause within the loop
may reduce the power consumption."

A new public header file env_dpdk.h has been introduced, and function spdk_env_dpdk_post_init
is added into it. If user is using DPDK, and already called rte_eal_init, then include
include/spdk/env_dpdk.h, and call spdk_env_dpdk_post_init() instead of spdk_env_init.

ISA-L has been added as an SPDK submodule. ISA-L is enabled by default on x86 architecture
to accelerate algorithms such as CRC for iSCSI and NVMe-oF. Users may still disable ISA-L
by explicitly passing --without-isal to the configure script.


A new uuid API spdk_uuid_copy was added to make a copy of the source uuid.

An new parameter init_crc representing the initial CRC value was added to
spdk_crc16_t10dif. The parameter can be used to calculate a CRC value spanning
multiple separate buffers.

New DIF APIs were added to generate and verify DIF by byte granularity for both DIF and DIX
formats. Among them, DIF with copy APIs will be usable to emulate DIF operations such as DIF
insert and strip.

Added spdk_strtol and spdk_strtoll to provide additional error checking around strtol
and strtoll.

Added spdk_sprintf_append_realloc and spdk_vsprintf_append_realloc for appending a string
with automatic buffer re-allocation.


Wrapper functions spdk_nvme_ctrlr_security_send() and spdk_nvme_ctrlr_security_receive() are
introduced to support further security protocol development.

admin_timeout_ms was added to NVMe controller initialization options, users
can change the default value when probing a controller.

Add two new fields "header_digest" and "data_digest" in struct spdk_nvme_ctrlr_opts,
it will be used to enable the digest support for the NVMe/TCP transport.

Add a new TCP/IP transport(located in lib/nvme/nvme_tcp.c) in nvme driver. With
this new transport, it can be used to connect the NVMe-oF target with the
same TCP/IP support.

Added API, spdk_nvme_ctrlr_is_discovery(), to indicate whether the ctrlr
arg refers to a Discovery Controller or not.

Added an API function spdk_nvme_host_id_parse and corresponding object spdk_nvme_host_id
for parsing host address and host service ID arguments on a per connection basis.

The RPC construct_nvme_bdev now allows a user to specify a source address and service id for the host to
use when connecting to the controller backing the NVMe bdev.

NVMe-oF Target

The spdk_nvmf_tgt_opts struct has been deprecated in favor of spdk_nvmf_transport_opts.
Users will no longer be able to specify target wide I/O parameters. spdk_nvmf_tgt_listen
will also no longer implicitly initialize a transport with the default target options (since
there are none). Instead, a user must manually instantiate the transport with spdk_nvmf_transport_create
prior to calling spdk_nvmf_tgt_listen.

Related to the previous change, the rpc set_nvmf_target_options has been renamed to
set_nvmf_target_max_subsystems to indicate that this is the only target option available for the user to edit.

Added fields num_shared_buffers and buf_cache_size in struct spdk_nvmf_transport_opts,
and also updated the related rpc function nvmf_create_transport, to make this
configurable parameter available to users. The num_shared_buffers is used to
configure the shared buffer numbers of the transport used by RDMA or TCP transport.
buf_cache_size configures number of shared buffers to cache per poll group.


Add a new TCP/IP transport (located in lib/nvmf/tcp.c). With this tranport,
the SPDK NVMe-oF target can have a new transport, and can serve the NVMe-oF
protocol via TCP/IP from the host.

Added optional mechanism to modify the RDMA transport's behavior when creating protection domains and registering memory.
By default, the RDMA transport will use the ibverbs library to create protection domains and register memory.
Using spdk_nvme_rdma_init_hooks will subvert that and use an existing registration.


Added enable_bdev_histogram and get_bdev_histogram RPC commands to allow gathering latency data for specified bdev.
Please see documentation for more details.

Added required_alignment field to spdk_bdev, that specifies an alignment requirement for data buffers associated with an spdk_bdev_io.
Bdev layer will automatically double buffer any spdk_bdev_io that violates this alignment, before the spdk_bdev_io is submitted to the bdev module.

On shutdown, bdev unregister now proceeds in top-down fashion, with
claimed bdevs skipped (these will be unregistered later, when virtual
bdev built on top of the respective base bdev unclaims it). This
allows virtual bdevs to be shut down cleanly as opposed to the
previous behavior that didn't differentiate between hotremove and
planned shutdown.

The delete_bdev RPC is now deprecated. Users should instead use the specific deletion RPC
for the bdev type to be removed (i.e. delete_malloc_bdev).

Added support for separate bandwidth rate limits for read and write to QoS in bdev layer.

Bdev I/O statistics now track unmap opertations.

logical volumes

Logical volume bdev can now be marked as read only using set_read_only_lvol_bdev RPC.
This allows for basing clones on top of lvol_bdev without first creating a snapshot.

Added option to change method for data erasure when deleting lvol or resizing down.
Default of unmapping clusters can now be changed to writing zeroes or no operation.


"trace flags" are now referred to as "log flags" in the SPDK log API. The
set_trace_flag, clear_trace_flag and get_trace_flags RPCs are now deprecated,
and set_log_flag, clear_log_flag and get_log_flags RPCs have been added.


New trace_record application was added. It can be used to poll spdk trace shm file and
append any new trace entries into another specified file. This can help retain those entries
that would otherwise be overwritten in the shm file. See
Capturing sufficient trace events
for more details.

Number of trace entries in circular buffer per lcore can now be assigned by starting SPDK app
with argument "--num-trace-entries " provided.

New get_tpoint_group_mask RPC was added to get current tpoint_group_mask, and
each tpoint group status.
New enable_tpoint_group and disable_tpoint_group RPC were added to enable or
disable a specific tpoint group.


EXPERIMENTAL: Added basic flash translation layer module allowing for using Open Channel SSDs as
block devices. The module is split into the library (located in lib/ftl) and bdev_ftl
(lib/bdev/ftl). See the documentation for more details.


A security vulnerability has been identified and fixed in the SPDK vhost target. A malicious
vhost client (i.e. virtual machine) could carefully construct a circular descriptor chain which
would result in a partial denial of service in the SPDK vhost target. These types of descriptor
chains are now properly detected by the vhost target. All SPDK vhost users serving untrusted
vhost clients are strongly recommended to upgrade. (Reported by Dima Stepanov and Evgeny

Vhost SCSI and Vhost Block devices can now accept multiple connections on the same socket file.
Each connection (internally called a vhost session) will have access to the same storage, but
will use different virtqueues, different features and possibly different memory.

vhost scsi

SCSI target hotremove can now be performed even without the VIRTIO_SCSI_F_HOTPLUG feature negotiated.
Regardless of VIRTIO_SCSI_F_HOTPLUG support, the hotremoval will be still reported through SCSI sense codes.


DPDK submodule was updated to DPDK 18.11. Note that SPDK does not fully leverage the new
multi-process device hotplug yet and continues to work the same way it always did.

Dropped support for DPDK 16.07 and earlier, which SPDK won't even compile with right now.


The following RPC commands deprecated in the previous release are now removed:

  • construct_virtio_user_scsi_bdev
  • construct_virtio_pci_scsi_bdev
  • construct_virtio_user_blk_bdev
  • construct_virtio_pci_blk_bdev
  • remove_virtio_scsi_bdev
  • construct_nvmf_subsystem


The configure options --with-raid and --without-raid that were deprecated in the previous
release are now removed.


Starting nbd using spdk_nbd_start is now performed asynchronously.

net framework

Net framework initialization and finish is now done asynchronously.


Added spdk_rpc_is_method_allowed function for checking whether method is permitted in a given state.
Added spdk_rpc_get_state to check current state of RPC server.
RPC wait_subsystem_init has been added to allow clients to block untill all subsystems are initialized.

json rpc

JSON RPC client is now running in non-blocking mode. Requests are sent and received during spdk_jsonrpc_client_poll.
JSON RPC server can now recieve a callback on connection termination or server shutdown using spdk_jsonrpc_conn_add_close_cb
and spdk_jsonrpc_conn_del_close_cb.

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