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2025-12-10dm raid: add documentation for takeover/reshape raid1 -> raid5 table line ↵Heinz Mauelshagen
examples Also enhance possible takeover/reshape information and do some reformatting. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-11-18dm verity fec: Expose corrected block count via statusShubhankar Mishra
Enhance visibility into dm-verity Forward Error Correction (FEC) activity. While FEC can correct on-disk corruptions, the number of successful correction events is not readily exposed through a standard interface. This change integrates FEC statistics into the verity target's .status handler for STATUSTYPE_INFO. The info output now includes count of corrected block by FEC. The counter is a per-device instance atomic64_t, maintained within the struct dm_verity_fec, tracking blocks successfully repaired by FEC on this specific device instance since it was created. This approach aligns with the standard Device Mapper mechanism for targets to report runtime information, as used by other targets like dm-integrity. This patch also updates Documentation/admin-guide/device-mapper/verity.rst to reflect the new status information. Tested: Induced single-bit errors on a block device protected by dm-verity with FEC on android phone. Confirmed 'dmctl status <device>' on Android reports an incrementing 'fec_corrected_blocks' count after the corrupted blocks were accessed. Signed-off-by: Shubhankar Mishra <shubhankarm@google.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-08-25dm-pcache: add persistent cache target in device-mapperDongsheng Yang
This patch introduces dm-pcache, a new DM target that places a DAX- capable persistent-memory device in front of any slower block device and uses it as a high-throughput, low-latency cache. Design highlights ----------------- - DAX data path – data is copied directly between DRAM and the pmem mapping, bypassing the block layer’s overhead. - Segmented, crash-consistent layout - all layout metadata are dual-replicated CRC-protected. - atomic kset flushes; key replay on mount guarantees cache integrity even after power loss. - Striped multi-tree index - Multi‑tree indexing for high parallelism. - overlap-resolution logic ensures non-intersecting cached extents. - Background services - write-back worker flushes dirty keys in order, preserving backing-device crash consistency. This is important for checkpoint in cloud storage. - garbage collector reclaims clean segments when utilisation exceeds a tunable threshold. - Data integrity – optional CRC32 on cached payload; metadata always protected. Comparison with existing block-level caches --------------------------------------------------------------------------------------------------------------------------------- | Feature | pcache (this patch) | bcache | dm-writecache | |----------------------------------|---------------------------------|------------------------------|---------------------------| | pmem access method | DAX | bio (block I/O) | DAX | | Write latency (4 K rand-write) | ~5 µs | ~20 µs | ~5 µs | | Concurrency | multi subtree index | global index tree | single tree + wc_lock | | IOPS (4K randwrite, 32 numjobs) | 2.1 M | 352 K | 283 K | | Read-cache support | YES | YES | NO | | Deployment | no re-format of backend | backend devices must be | no re-format of backend | | | | reformatted | | | Write-back ordering | log-structured; | no ordering guarantee | no ordering guarantee | | | preserves app-IO-order | | | | Data integrity checks | metadata + data CRC(optional) | metadata CRC only | none | --------------------------------------------------------------------------------------------------------------------------------- Signed-off-by: Dongsheng Yang <dongsheng.yang@linux.dev> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-08-19dm-vdo: Promote dm-vdo title to title headingBagas Sanjaya
dm-vdo docs currently has no explicit title heading but instead there are multiple section headings as top-level heading. As such, these sections are rendered as titles and inflates number of entries in the toctree index. Promote the first section heading ("dm-vdo") to title heading. Fixes: 04bf7ac646ab ("dm: add documentation for dm-vdo target") Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-08-19docs: device-mapper: fixed spelling mistakes in documentationSoham Metha
found/fixed the following typos - flushs -> flushes in `Documentation/admin-guide/device-mapper/delay.rst` Signed-off-by: Soham Metha <sohammetha01@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-08-19docs: device-mapper: fix typos in delay.rst and vdo-design.rstShubham Sharma
Fixed the following typos in device-mapper documentation: - explicitely -> explicitly - approriate -> appropriate Signed-off-by: Shubham Sharma <slopixelz@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-07-31dm-thin: update the documentationLongPing Wei
1. convert KB/MB/GB to KiB/MiB/GiB; 2. change the number of sectors for 128MiB from 256000 to 262144 as 256000 sectors is neither 128 MB nor 128 MiB. Signed-off-by: LongPing Wei <weilongping@oppo.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-03-28dm-verity: support block number limits for different ioprio classesLongPing Wei
Calling verity_verify_io in bh for IO of all sizes is not suitable for embedded devices. From our tests, it can improve the performance of 4K synchronise random reads. For example: ./fio --name=rand_read --ioengine=psync --rw=randread --bs=4K \ --direct=1 --numjobs=8 --runtime=60 --time_based --group_reporting \ --filename=/dev/block/mapper/xx-verity But it will degrade the performance of 512K synchronise sequential reads on our devices. For example: ./fio --name=read --ioengine=psync --rw=read --bs=512K --direct=1 \ --numjobs=8 --runtime=60 --time_based --group_reporting \ --filename=/dev/block/mapper/xx-verity A parameter array is introduced by this change. And users can modify the default config by /sys/module/dm_verity/parameters/use_bh_bytes. The default limits for NONE/RT/BE is set to 8192. The default limits for IDLE is set to 0. Call verity_verify_io directly when verity_end_io is not in hardirq. Signed-off-by: LongPing Wei <weilongping@oppo.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-02-03dm-crypt: Document integrity_key_size option.Milan Broz
This patch adds documentation for new option introduced in commit 4441686b24a1 ("dm-crypt: Allow to specify the integrity key size as option"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-02-03dm-integrity: Document Inline mode for storing integrity dataMilan Broz
This patch adds documentation for new 'I' mode for dm-integrity introduced in commit fb0987682c62 ("dm-integrity: introduce the Inline mode"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-02-03dm-verity: Document restart_on_error and panic_on_error optionsMilan Broz
This patch adds documentation for options introduced in commit f811b83879fb ("dm-verity: introduce the options restart_on_error and panic_on_error"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-09-27Merge tag 'for-6.12/dm-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mikulas Patocka: - Misc VDO fixes - Remove unused declarations dm_get_rq_mapinfo() and dm_zone_map_bio() - Dm-delay: Improve kernel documentation - Dm-crypt: Allow to specify the integrity key size as an option - Dm-bufio: Remove pointless NULL check - Small code cleanups: Use ERR_CAST; remove unlikely() around IS_ERR; use __assign_bit - Dm-integrity: Fix gcc 5 warning; convert comma to semicolon; fix smatch warning - Dm-integrity: Support recalculation in the 'I' mode - Revert "dm: requeue IO if mapping table not yet available" - Dm-crypt: Small refactoring to make the code more readable - Dm-cache: Remove pointless error check - Dm: Fix spelling errors - Dm-verity: Restart or panic on an I/O error if restart or panic was requested - Dm-verity: Fallback to platform keyring also if key in trusted keyring is rejected * tag 'for-6.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (26 commits) dm verity: fallback to platform keyring also if key in trusted keyring is rejected dm-verity: restart or panic on an I/O error dm: fix spelling errors dm-cache: remove pointless error check dm vdo: handle unaligned discards correctly dm vdo indexer: Convert comma to semicolon dm-crypt: Use common error handling code in crypt_set_keyring_key() dm-crypt: Use up_read() together with key_put() only once in crypt_set_keyring_key() Revert "dm: requeue IO if mapping table not yet available" dm-integrity: check mac_size against HASH_MAX_DIGESTSIZE in sb_mac() dm-integrity: support recalculation in the 'I' mode dm integrity: Convert comma to semicolon dm integrity: fix gcc 5 warning dm: Make use of __assign_bit() API dm integrity: Remove extra unlikely helper dm: Convert to use ERR_CAST() dm bufio: Remove NULL check of list_entry() dm-crypt: Allow to specify the integrity key size as option dm: Remove unused declaration and empty definition "dm_zone_map_bio" dm delay: enhance kernel documentation ...
2024-08-21dm-crypt: Allow to specify the integrity key size as optionIngo Franzki
For the MAC based integrity operation, the integrity key size (i.e. key_mac_size) is currently set to the digest size of the used digest. For wrapped key HMAC algorithms, the key size is independent of the cryptographic key size. So there is no known size of the mac key in such cases. The desired key size can optionally be specified as argument when the dm-crypt device is configured via 'integrity_key_size:%u'. If no integrity_key_size argument is specified, the mac key size is still set to the digest size, as before. Increase version number to 1.28.0 so that support for the new argument can be detected by user space (i.e. cryptsetup). Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com> Reviewed-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-08-21dm delay: enhance kernel documentationHeinz Mauelshagen
This commit improves documentation of the dm-delay target. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-08-21dm vdo: add dmsetup message for returning configuration infoBruce Johnston
Add a new dmsetup message called config, which will return useful configuration information for the vdo volume and the uds index associated with it. The output is a YAML string, and contains a version number to allow future additions to the content. Signed-off-by: Bruce Johnston <bjohnsto@redhat.com> Signed-off-by: Matthew Sakai <msakai@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-08-13Documentation: dm-crypt.rst warning + error fixDaniel Yang
While building kernel documention using make htmldocs command, I was getting unexpected indentation error. Single description was given for two module parameters with wrong indentation. So, I corrected the indentation of both parameters and the description. Signed-off-by: Shibu kumar <shibukumar.bit@gmail.com> Signed-off-by: Daniel Yang <danielyangkang@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Fixes: 0d815e3400e6 ("dm-crypt: limit the size of encryption requests")
2024-08-07docs: dm-crypt: Removal of unexpected indentation errorShibu Kumar
Add the required indentation to fix this docs build error: Documentation/admin-guide/device-mapper/dm-crypt.rst:167: ERROR: Unexpected indentation. Also split the documentation for read and write into separate blocks. Signed-off-by: Shibu kumar shibukumar.bit@gmail.com [jc: rewrote changelog] Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20240803183306.32425-1-shibukumar.bit@gmail.com
2024-07-19dm vdo: fix a minor formatting issue in vdo.rstMasatake YAMATO
Signed-off-by: Masatake YAMATO <yamato@redhat.com> Signed-off-by: Matthew Sakai <msakai@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-07-10dm-crypt: limit the size of encryption requestsMikulas Patocka
There was a performance regression reported where dm-crypt would perform worse on new kernels than on old kernels. The reason is that the old kernels split the bios to NVMe request size (that is usually 65536 or 131072 bytes) and the new kernels pass the big bios through dm-crypt and split them underneath. If a big 1MiB bio is passed to dm-crypt, dm-crypt processes it on a single core without parallelization and this is what causes the performance degradation. This commit introduces new tunable variables /sys/module/dm_crypt/parameters/max_read_size and /sys/module/dm_crypt/parameters/max_write_size that specify the maximum bio size for dm-crypt. Bios larger than this value are split, so that they can be encrypted in parallel by multiple cores. If these variables are '0', a default 131072 is used. Splitting bios may cause performance regressions in other workloads - if this happens, the user should increase the value in max_read_size and max_write_size variables. max_read_size: 128k 2399MiB/s 256k 2368MiB/s 512k 1986MiB/s 1024 1790MiB/s max_write_size: 128k 1712MiB/s 256k 1651MiB/s 512k 1537MiB/s 1024k 1332MiB/s Note that if you run dm-crypt inside a virtual machine, you may need to do "echo numa >/sys/module/workqueue/parameters/default_affinity_scope" to improve performance. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Tested-by: Laurence Oberman <loberman@redhat.com>
2024-04-16dm-crypt: add the optional "high_priority" flagMikulas Patocka
When WQ_HIGHPRI was used for the dm-crypt kcryptd workqueue it was reported that dm-crypt performs badly when the system is loaded[1]. Because of reports of audio skipping, dm-crypt stopped using WQ_HIGHPRI with commit f612b2132db5 (Revert "dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues"). But it has since been determined that WQ_HIGHPRI provides improved performance (with reduced latency) for highend systems with much more resources than those laptop/desktop users which suffered from the use of WQ_HIGHPRI. As such, add an option "high_priority" that allows the use of WQ_HIGHPRI for dm-crypt's workqueues and also sets the write_thread to nice level MIN_NICE (-20). This commit makes it optional, so that normal users won't be harmed by it. [1] https://listman.redhat.com/archives/dm-devel/2023-February/053410.html Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2024-03-07dm vdo: document minimum metadata size requirementsMatthew Sakai
Signed-off-by: Matthew Sakai <msakai@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2024-03-04dm vdo: document log_level parameterKen Raeburn
Signed-off-by: Ken Raeburn <raeburn@redhat.com> Signed-off-by: Matthew Sakai <msakai@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2024-02-20dm vdo: add vio life cycle details to design docMatthew Sakai
Add more documentation details for most aspects of the data_vio read and write processes. Also correct a few minor errors and rewrite some text for clarity. Signed-off-by: Matthew Sakai <msakai@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2024-02-20dm vdo: add vdo documentation to device-mapper indexMatthew Sakai
Signed-off-by: Matthew Sakai <msakai@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2024-02-20dm: add documentation for dm-vdo targetMatthew Sakai
This adds the admin-guide documentation for dm-vdo. vdo.rst is the guide to using dm-vdo. vdo-design is an overview of the design of dm-vdo. Co-developed-by: J. corwin Coburn <corwin@hurlbutnet.net> Signed-off-by: J. corwin Coburn <corwin@hurlbutnet.net> Signed-off-by: Matthew Sakai <msakai@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-06-22Documentation: dm-integrity: Document an example of how the tunables relate.Russell Harmon
Signed-off-by: Russell Harmon <eatnumber1@gmail.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-06-22Documentation: dm-integrity: Document default values.Russell Harmon
Signed-off-by: Russell Harmon <eatnumber1@gmail.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-06-22Documentation: dm-integrity: Document the meaning of "buffer".Russell Harmon
"Buffers" are buffers of the metadata/checksum area of dm-integrity. They are always at most as large as a single metadata area on-disk, but may be smaller. Signed-off-by: Russell Harmon <eatnumber1@gmail.com> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-06-22Documentation: dm-integrity: Fix minor grammatical error.Russell Harmon
"where dm-integrity uses bitmap" becomes "where dm-integrity uses a bitmap" Signed-off-by: Russell Harmon <eatnumber1@gmail.com> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-06-16dm flakey: introduce random_read_corrupt and random_write_corrupt optionsMikulas Patocka
The random_read_corrupt and random_write_corrupt options corrupt a random byte in a bio with the provided probability. The corruption only happens in the "down" interval. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-04-19dm flakey: add an "error_reads" optionMikulas Patocka
dm-flakey returns error on reads if no other argument is specified. This commit simplifies associated logic while formalizing an "error_reads" argument and an ERROR_READS flag. If no argument is specified, set ERROR_READS flag so that it behaves just like before this commit. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-02Documentation: admin-guide: correct spellingRandy Dunlap
Correct spelling problems for Documentation/admin-guide/ as reported by codespell. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: cgroups@vger.kernel.org Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@kernel.org> Cc: dm-devel@redhat.com Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: linux-media@vger.kernel.org Cc: linux-mm@kvack.org Link: https://lore.kernel.org/r/20230129231053.20863-2-rdunlap@infradead.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-12-02dm init: add dm-mod.waitfor to wait for asynchronously probed block devicesPeter Korsgaard
Just calling wait_for_device_probe() is not enough to ensure that asynchronously probed block devices are available (E.G. mmc, usb), so add a "dm-mod.waitfor=<device1>[,..,<deviceN>]" parameter to get dm-init to explicitly wait for specific block devices before initializing the tables with logic similar to the rootwait logic that was introduced with commit cc1ed7542c8c ("init: wait for asynchronously scanned block devices"). E.G. with dm-verity on mmc using: dm-mod.waitfor="PARTLABEL=hash-a,PARTLABEL=root-a" [ 0.671671] device-mapper: init: waiting for all devices to be available before creating mapped devices [ 0.671679] device-mapper: init: waiting for device PARTLABEL=hash-a ... [ 0.710695] mmc0: new HS200 MMC card at address 0001 [ 0.711158] mmcblk0: mmc0:0001 004GA0 3.69 GiB [ 0.715954] mmcblk0boot0: mmc0:0001 004GA0 partition 1 2.00 MiB [ 0.722085] mmcblk0boot1: mmc0:0001 004GA0 partition 2 2.00 MiB [ 0.728093] mmcblk0rpmb: mmc0:0001 004GA0 partition 3 512 KiB, chardev (249:0) [ 0.738274] mmcblk0: p1 p2 p3 p4 p5 p6 p7 [ 0.751282] device-mapper: init: waiting for device PARTLABEL=root-a ... [ 0.751306] device-mapper: init: all devices available [ 0.751683] device-mapper: verity: sha256 using implementation "sha256-generic" [ 0.759344] device-mapper: ioctl: dm-0 (vroot) is ready [ 0.766540] VFS: Mounted root (squashfs filesystem) readonly on device 254:0. Signed-off-by: Peter Korsgaard <peter@korsgaard.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-10-18dm verity: Add documentation for try_verify_in_tasklet optionMilan Broz
Add documentation that was missing from commit 5721d4e5a9cd ("dm verity: Add optional "try_verify_in_tasklet" feature"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-07-14dm writecache: count number of blocks discarded, not number of discard biosMikulas Patocka
Change dm-writecache, so that it counts the number of blocks discarded instead of the number of discard bios. Make it consistent with the read and write statistics counters that were changed to count the number of blocks instead of bios. Fixes: e3a35d03407c ("dm writecache: add event counters") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-07-14dm writecache: count number of blocks written, not number of write biosMikulas Patocka
Change dm-writecache, so that it counts the number of blocks written instead of the number of write bios. Bios can be split and requeued using the dm_accept_partial_bio function, so counting bios caused inaccurate results. Fixes: e3a35d03407c ("dm writecache: add event counters") Reported-by: Yu Kuai <yukuai1@huaweicloud.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-07-14dm writecache: count number of blocks read, not number of read biosMikulas Patocka
Change dm-writecache, so that it counts the number of blocks read instead of the number of read bios. Bios can be split and requeued using the dm_accept_partial_bio function, so counting bios caused inaccurate results. Fixes: e3a35d03407c ("dm writecache: add event counters") Reported-by: Yu Kuai <yukuai1@huaweicloud.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-07-07Documentation: dm writecache: Render status list as listBagas Sanjaya
The status list isn't rendered as list, but rather as normal paragraph, because there is missing blank line between "Status:" line and the list. Fix the issue by adding the blank line separator. Fixes: 48debafe4f2fea ("dm: add writecache target") Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-07-07Documentation: dm writecache: add blank line before optional parametersMauro Carvalho Chehab
Otherwise this warning occurs: Documentation/admin-guide/device-mapper/writecache.rst:23: WARNING: Unexpected indentation. Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2021-08-20dm ima: update dm documentation for ima measurement supportTushar Sugandhi
The ima documentation for measuring DM targets (dm-ima.rst) is missing the attribute information for the targets - 'cache', 'integrity', 'multipath', and 'snapshot'. It is also missing the grammar for various DM events and targets, which can help the attestation servers to determine what data to expect for a given DM device. Further, the documentation needs to be updated to incorporate code changes made to DM ima events and targets as part of this patch series. For instance, prefixing the event names with "dm_", adding the DM version to events, prefixing the table hashes in the ima log with the hash algorithm etc. There are warnings reported by 'make htmldocs' on dm-ima.rst, which need to be fixed. And lastly, the expected behavior needs to be documented when the configuration CONFIG_IMA_DISABLE_HTABLE is disabled. Update the documentation to add examples for 'cache', 'integrity', 'multipath', and 'snapshot' targets. Add the grammar for various DM events and targets in Backus Naur form, so that the attestation servers can interpret and act on the ima measurements for DM target. Fix htmldocs warnings in dm-ima.rst. Update the documentation to be consistent with the code changes that are part of this patch series. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-08-10dm: add documentation for IMA measurement supportTushar Sugandhi
To interpret various DM target measurement data in IMA logs, a separate documentation page is needed under Documentation/admin-guide/device-mapper. Add documentation to help system administrators and attestation client/server component owners to interpret the measurement data generated by various DM targets, on various device/table state changes. Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-08-10dm writecache: add event countersMikulas Patocka
Add 10 counters for various events (hit, miss, etc) and export them in the status line (accessed from userspace with "dmsetup status"). Also add a message "clear_stats" that resets these counters. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-06-28dm writecache: make writeback pause configurableMikulas Patocka
Commit 95b88f4d71cb953e02206be3c757083601391a0f ("dm writecache: pause writeback if cache full and origin being written directly") introduced a code that pauses cache flushing if we are issuing writes directly to the origin. Improve that initial commit by making the timeout code configurable (via the option "pause_writeback"). Also change the default from 1s to 3s because it performed better. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-06-25dm writecache: add optional "metadata_only" parameterMikulas Patocka
Add a "metadata_only" parameter that when present: only metadata is promoted to the cache. This option improves performance for heavier REQ_META workloads (e.g. device-mapper-test-suite's "git clone and checkout" benchmark improves from 341s to 312s). Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-06-25dm writecache: add "cleaner" and "max_age" to DocumentationMike Snitzer
Backfill missing Documentation. Fixes: 93de44eb3fc8 ("dm writecache: implement the "cleaner" policy") Fixes: 3923d4854e18 ("dm writecache: implement gradual cleanup") Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-02-22Merge tag 'for-5.12/dm-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mike Snitzer: - Fix DM integrity's HMAC support to provide enhanced security of internal_hash and journal_mac capabilities. - Various DM writecache fixes to address performance, fix table output to match what was provided at table creation, fix writing beyond end of device when shrinking underlying data device, and a couple other small cleanups. - Add DM crypt support for using trusted keys. - Fix deadlock when swapping to DM crypt device by throttling number of in-flight REQ_SWAP bios. Implemented in DM core so that other bio-based targets can opt-in by setting ti->limit_swap_bios. - Fix various inverted logic bugs in the .iterate_devices callout functions that are used to assess if specific feature or capability is supported across all devices being combined/stacked by DM. - Fix DM era target bugs that exposed users to lost writes or memory leaks. - Add DM core support for passing through inline crypto support of underlying devices. Includes block/keyslot-manager changes that enable extending this support to DM. - Various small fixes and cleanups (spelling fixes, front padding calculation cleanup, cleanup conditional zoned support in targets, etc). * tag 'for-5.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (31 commits) dm: fix deadlock when swapping to encrypted device dm: simplify target code conditional on CONFIG_BLK_DEV_ZONED dm: set DM_TARGET_PASSES_CRYPTO feature for some targets dm: support key eviction from keyslot managers of underlying devices dm: add support for passing through inline crypto support block/keyslot-manager: Introduce functions for device mapper support block/keyslot-manager: Introduce passthrough keyslot manager dm era: only resize metadata in preresume dm era: Use correct value size in equality function of writeset tree dm era: Fix bitset memory leaks dm era: Verify the data block size hasn't changed dm era: Reinitialize bitset cache before digesting a new writeset dm era: Update in-core bitset after committing the metadata dm era: Recover committed writeset after crash dm writecache: use bdev_nr_sectors() instead of open-coded equivalent dm writecache: fix writing beyond end of underlying device when shrinking dm table: remove needless request_queue NULL pointer checks dm table: fix zoned iterate_devices based device capability checks dm table: fix DAX iterate_devices based device capability checks dm table: fix iterate_devices based device capability checks ...
2021-02-21Merge branch 'linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto update from Herbert Xu: "API: - Restrict crypto_cipher to internal API users only. Algorithms: - Add x86 aesni acceleration for cts. - Improve x86 aesni acceleration for xts. - Remove x86 acceleration of some uncommon algorithms. - Remove RIPE-MD, Tiger and Salsa20. - Remove tnepres. - Add ARM acceleration for BLAKE2s and BLAKE2b. Drivers: - Add Keem Bay OCS HCU driver. - Add Marvell OcteonTX2 CPT PF driver. - Remove PicoXcell driver. - Remove mediatek driver" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (154 commits) hwrng: timeriomem - Use device-managed registration API crypto: hisilicon/qm - fix printing format issue crypto: hisilicon/qm - do not reset hardware when CE happens crypto: hisilicon/qm - update irqflag crypto: hisilicon/qm - fix the value of 'QM_SQC_VFT_BASE_MASK_V2' crypto: hisilicon/qm - fix request missing error crypto: hisilicon/qm - removing driver after reset crypto: octeontx2 - fix -Wpointer-bool-conversion warning crypto: hisilicon/hpre - enable Elliptic curve cryptography crypto: hisilicon - PASID fixed on Kunpeng 930 crypto: hisilicon/qm - fix use of 'dma_map_single' crypto: hisilicon/hpre - tiny fix crypto: hisilicon/hpre - adapt the number of clusters crypto: cpt - remove casting dma_alloc_coherent crypto: keembay-ocs-aes - Fix 'q' assignment during CCM B0 generation crypto: xor - Fix typo of optimization hwrng: optee - Use device-managed registration API crypto: arm64/crc-t10dif - move NEON yield to C code crypto: arm64/aes-ce-mac - simplify NEON yield crypto: arm64/aes-neonbs - remove NEON yield calls ...
2021-02-03dm crypt: support using trusted keysAhmad Fatoum
Commit 27f5411a718c ("dm crypt: support using encrypted keys") extended dm-crypt to allow use of "encrypted" keys along with "user" and "logon". Along the same lines, teach dm-crypt to support "trusted" keys as well. Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-02-03dm integrity: introduce the "fix_hmac" argumentMikulas Patocka
The "fix_hmac" argument improves security of internal_hash and journal_mac: - the section number is mixed to the mac, so that an attacker can't copy sectors from one journal section to another journal section - the superblock is protected by journal_mac - a 16-byte salt stored in the superblock is mixed to the mac, so that the attacker can't detect that two disks have the same hmac key and also to disallow the attacker to move sectors from one disk to another Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reported-by: Daniel Glockner <dg@emlix.com> Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> # ReST fix Tested-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-01-29crypto: salsa20 - remove Salsa20 stream cipher algorithmArd Biesheuvel
Salsa20 is not used anywhere in the kernel, is not suitable for disk encryption, and widely considered to have been superseded by ChaCha20. So let's remove it. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>