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Subject[7/7] dst: kconfig and makefile changes.
Signed-off-by: Evgeniy Polaykov <>

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 61ad8d6..2a92cd8 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -445,4 +445,6 @@ config BLK_DEV_HD

If unsure, say N.

+source "drivers/block/dst/Kconfig"
endif # BLK_DEV
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 204332b..6400de0 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -32,3 +32,5 @@ obj-$(CONFIG_BLK_DEV_UB) += ub.o
obj-$(CONFIG_BLK_DEV_HD) += hd.o

obj-$(CONFIG_XEN_BLKDEV_FRONTEND) += xen-blkfront.o
+obj-$(CONFIG_DST) += dst/
diff --git a/drivers/block/dst/Kconfig b/drivers/block/dst/Kconfig
new file mode 100644
index 0000000..12ffa37
--- /dev/null
+++ b/drivers/block/dst/Kconfig
@@ -0,0 +1,71 @@
+config DST
+ tristate "Distributed storage"
+ depends on NET && CRYPTO && SYSFS
+ select CONNECTOR
+ select LIBCRC32C
+ ---help---
+ DST is a network block device storage, which can be used to organize
+ exported storages on the remote nodes into the local block device.
+ DST is a network block device storage, which can be used to organize
+ exported storages on the remote nodes into the local block device.
+ DST works on top of any network media and protocol, it is just a matter
+ of configuration utility to understand the correct addresses. The most
+ common example is TCP over IP allows to pass through firewalls and
+ created remote backup storage in the different datacenter. DST requires
+ single port to be enabled on the exporting node and outgoing connections
+ on the local node.
+ DST works with in-kernel client and server, which improves the performance
+ eliminating unneded data copies and allows not to depend on the version
+ of the external IO components. It requires userspace configuration utility
+ though.
+ DST uses transaction model, when each store has to be explicitly acked
+ from the remote node to be considered as successfully written. There
+ may be lots of in-flight transactions. When remote host does not ack
+ the transaction it will be resent predefined number of times with specified
+ timeouts between them. All those parameters are configurable. Transactions
+ are marked as failed after all resends completed unsuccessfully, having
+ long enough resend timeout and/or large number of resends allows not to
+ return error to the higher (FS usually) layer in case of short network
+ problems or remote node outages. In case of network RAID setup this means
+ that storage will not degrade until transactions are marked as failed, and
+ thus will not force checksum recalculation and data rebuild. In case of
+ connection failure DST will try to reconnect to the remote node automatically.
+ DST sends ping commands at idle time to detect if remote node is alive.
+ Because of transactional model it is possible to use zero-copy sending
+ without worry of data corruption (which in turn could be detected by the
+ strong checksums though).
+ DST may fully encrypt the data channel in case of untrusted channel and implement
+ strong checksum of the transferred data. It is possible to configure algorithms
+ and crypto keys, they should match on both sides of the network channel.
+ Crypto processing does not introduce noticeble performance overhead, since DST
+ uses configurable pool of threads to perform crypto processing.
+ DST utilizes memory pool model of all its transaction allocations (it is the
+ only additional allocation on the client) and server allocations (bio pools,
+ while pages are allocated from the slab).
+ At startup DST performs a simple negotiation with the export node to determine
+ access permissions and size of the exported storage. It can be extended if
+ new parameters should be autonegotiated.
+ DST carries block IO flags in the protocol, which allows to transparently implement
+ barriers and sync/flush operations. Those flags are used in the export node where
+ IO against the local storage is performed, which means that sync write will be sync
+ on the remote node too, which in turn improves data integrity and improved resistance
+ to errors and data corruption during power outages or storage damages.
+ Homepage:
+ Userspace configuration utility and the latest releases:
+config DST_DEBUG
+ bool "DST debug"
+ depends on DST
+ ---help---
+ This option will turn HEAVY debugging of the DST.
+ Turn it on ONLY if you have to debug some really obscure problem.
diff --git a/drivers/block/dst/Makefile b/drivers/block/dst/Makefile
new file mode 100644
index 0000000..3a8b0cf
--- /dev/null
+++ b/drivers/block/dst/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_DST) += nst.o
+nst-y := dcore.o state.o export.o thread_pool.o crypto.o trans.o

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