Hi Jens. Hi Jonathan. Hi all. I am happy to offer a modified version of the Block Devices Snapshots Module. It allows to create non-persistent snapshots of any block devices. The main purpose of such snapshots is to provide backups of block devices. See more in Documentation/block/blksnap.rst. The Block Device Filtering Mechanism is added to the block layer. This allows to attach and detach block device filters to the block layer. Filters allow to extend the functionality of the block layer. See more in Documentation/block/blkfilter.rst. A tool, a library for working with blksnap and tests can be found at www.github.com/veeam/blksnap. The first version was suggested at 13 June 2022. Many thanks to Christoph Hellwig and Randy Dunlap for the review of that version. Changes: - Forgotten "static" declarations have been added. - The text of the comments has been corrected. - It is possible to connect only one filter, since there are no others in upstream. - Do not have additional locks for attach/detach filter. - blksnap.h moved to include/uapi/. - #pragma once and commented code removed. - uuid_t removed from user API. - Removed default values for module parameters from the configuration file. - The debugging code for tracking memory leaks has been removed. - Simplified Makefile. - Optimized work with large memory buffers, CBT tables are now in virtual memory. - The allocation code of minor numbers has been optimized. - The implementation of the snapshot image block device has been simplified, now it is a bio-based block device. - Removed initialization of global variables with null values. - Only one bio is used to copy one chunk. - Checked on ppc64le. The v1 version was suggested at 2 November 2022. Many thanks to Fabio Fantoni for his for his participation in the "blksnap" project on github and Jonathan Corbet for his article https://lwn.net/Articles/914031/. Thanks to the impartial kernel test robot. Changes: - Added documentation for Block Device Filtering Mechanism. - Added documentation for Block Devices Snapshots Module (blksnap). - The MAINTAINERS file has been updated. - Optimized queue code for snapshot images. - Fixed comments, log messages and code for better readability. Sergei Shtepa (21): documentation, blkfilter: Block Device Filtering Mechanism block, blkfilter: Block Device Filtering Mechanism documentation, capability: fix Generic Block Device Capability documentation, blksnap: Block Devices Snapshots Module block, blksnap: header file of the module interface block, blksnap: module management interface functions block, blksnap: init() and exit() functions block, blksnap: interaction with sysfs block, blksnap: attaching and detaching the filter and handling I/O units block, blksnap: map of change block tracking block, blksnap: minimum data storage unit of the original block device block, blksnap: buffer in memory for the minimum data storage unit block, blksnap: functions and structures for performing block I/O operations block, blksnap: storage for storing difference blocks block, blksnap: event queue from the difference storage block, blksnap: owner of information about overwritten blocks of the original block device block, blksnap: snapshot image block device block, blksnap: snapshot block, blksnap: Kconfig and Makefile block, blksnap: adds a blksnap to the kernel tree block, blksnap: adds a maintainer for new files Documentation/block/blkfilter.rst | 50 ++ Documentation/block/blksnap.rst | 348 ++++++++++++++ Documentation/block/capability.rst | 3 + Documentation/block/index.rst | 2 + MAINTAINERS | 14 + block/bdev.c | 70 +++ block/blk-core.c | 19 +- drivers/block/Kconfig | 2 + drivers/block/Makefile | 2 + drivers/block/blksnap/Kconfig | 12 + drivers/block/blksnap/Makefile | 18 + drivers/block/blksnap/cbt_map.c | 268 +++++++++++ drivers/block/blksnap/cbt_map.h | 114 +++++ drivers/block/blksnap/chunk.c | 345 ++++++++++++++ drivers/block/blksnap/chunk.h | 139 ++++++ drivers/block/blksnap/ctrl.c | 410 ++++++++++++++++ drivers/block/blksnap/ctrl.h | 9 + drivers/block/blksnap/diff_area.c | 655 +++++++++++++++++++++++++ drivers/block/blksnap/diff_area.h | 177 +++++++ drivers/block/blksnap/diff_buffer.c | 133 ++++++ drivers/block/blksnap/diff_buffer.h | 75 +++ drivers/block/blksnap/diff_io.c | 168 +++++++ drivers/block/blksnap/diff_io.h | 118 +++++ drivers/block/blksnap/diff_storage.c | 317 +++++++++++++ drivers/block/blksnap/diff_storage.h | 93 ++++ drivers/block/blksnap/event_queue.c | 86 ++++ drivers/block/blksnap/event_queue.h | 63 +++ drivers/block/blksnap/main.c | 164 +++++++ drivers/block/blksnap/params.h | 12 + drivers/block/blksnap/snapimage.c | 275 +++++++++++ drivers/block/blksnap/snapimage.h | 69 +++ drivers/block/blksnap/snapshot.c | 670 ++++++++++++++++++++++++++ drivers/block/blksnap/snapshot.h | 78 +++ drivers/block/blksnap/sysfs.c | 80 ++++ drivers/block/blksnap/sysfs.h | 7 + drivers/block/blksnap/tracker.c | 683 +++++++++++++++++++++++++++ drivers/block/blksnap/tracker.h | 74 +++ drivers/block/blksnap/version.h | 10 + include/linux/blk_types.h | 2 + include/linux/blkdev.h | 71 +++ include/uapi/linux/blksnap.h | 549 +++++++++++++++++++++ 41 files changed, 6452 insertions(+), 2 deletions(-) create mode 100644 Documentation/block/blkfilter.rst create mode 100644 Documentation/block/blksnap.rst create mode 100644 drivers/block/blksnap/Kconfig create mode 100644 drivers/block/blksnap/Makefile create mode 100644 drivers/block/blksnap/cbt_map.c create mode 100644 drivers/block/blksnap/cbt_map.h create mode 100644 drivers/block/blksnap/chunk.c create mode 100644 drivers/block/blksnap/chunk.h create mode 100644 drivers/block/blksnap/ctrl.c create mode 100644 drivers/block/blksnap/ctrl.h create mode 100644 drivers/block/blksnap/diff_area.c create mode 100644 drivers/block/blksnap/diff_area.h create mode 100644 drivers/block/blksnap/diff_buffer.c create mode 100644 drivers/block/blksnap/diff_buffer.h create mode 100644 drivers/block/blksnap/diff_io.c create mode 100644 drivers/block/blksnap/diff_io.h create mode 100644 drivers/block/blksnap/diff_storage.c create mode 100644 drivers/block/blksnap/diff_storage.h create mode 100644 drivers/block/blksnap/event_queue.c create mode 100644 drivers/block/blksnap/event_queue.h create mode 100644 drivers/block/blksnap/main.c create mode 100644 drivers/block/blksnap/params.h create mode 100644 drivers/block/blksnap/snapimage.c create mode 100644 drivers/block/blksnap/snapimage.h create mode 100644 drivers/block/blksnap/snapshot.c create mode 100644 drivers/block/blksnap/snapshot.h create mode 100644 drivers/block/blksnap/sysfs.c create mode 100644 drivers/block/blksnap/sysfs.h create mode 100644 drivers/block/blksnap/tracker.c create mode 100644 drivers/block/blksnap/tracker.h create mode 100644 drivers/block/blksnap/version.h create mode 100644 include/uapi/linux/blksnap.h -- 2.20.1
