feat: ec module by c3y1huang · Pull Request #72 · longhorn/spdk

c3y1huang · 2026-05-25T13:47:09Z

Which issue(s) this PR fixes:

Issue longhorn/longhorn#1061

What this PR does / why we need it:

Implement EC module.

Special notes for your reviewer:

None

Additional documentation or context

None

Copilot

Pull request overview

This PR introduces a new SPDK bdev_ec (erasure coding) module intended for Longhorn’s EC volumes, along with RPC/CLI surfaces, unit tests, and a small NVMe reconnect enhancement to refresh namespace capacity after a target-side resize.

Changes:

Add the bdev_ec module (WIB + unmapped-bitmap metadata, UNMAP fan-out, RMW path, resize support, and JSON-RPC handlers).
Add Python RPC/CLI bindings and a new unit test suite for EC bitmap/geometry logic.
Refresh NVMe namespace blockcnt during reconnect and notify upper layers of size changes.

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 16 comments.

Show a summary per file

File	Description
test/unit/unittest.sh	Runs the new EC unit test binary from the unit test driver script.
test/unit/lib/bdev/Makefile	Adds the EC unit-test subdirectory to the unit-test build.
test/unit/lib/bdev/ec/Makefile	New unit-test subdir makefile for EC tests.
test/unit/lib/bdev/ec/bdev_ec.c/Makefile	Builds the EC unit test source via the SPDK unittest makefile.
test/unit/lib/bdev/ec/bdev_ec.c/bdev_ec_ut.c	Adds unit tests covering geometry math and unmapped-bitmap blob logic.
python/spdk/rpc/bdev.py	Adds Python RPC client wrappers for EC lifecycle/ops RPCs.
python/spdk/cli/bdev.py	Adds CLI commands for EC create/delete/status/replace/rebuild/resize.
module/bdev/nvme/bdev_nvme.c	Refreshes namespace blockcnt during reconnect and notifies bdev layer.
module/bdev/Makefile	Adds `ec` module directory to the bdev module build list.
module/bdev/ec/Makefile	New build rules for the EC module library.
module/bdev/ec/bdev_ec.h	Adds the EC module’s public header/API surface.
module/bdev/ec/bdev_ec_wib.c	Implements WIB persist/load and WIB status query.
module/bdev/ec/bdev_ec_unmap.c	Implements UNMAP handling (bitmap-backed fan-out + split head/tail zero-fill).
module/bdev/ec/bdev_ec_rpc.c	Adds JSON-RPC handlers for EC lifecycle/data-plane/control operations.
module/bdev/ec/bdev_ec_rmw.c	Implements RMW path for sub-stripe writes (including zero-fill).
module/bdev/ec/bdev_ec_resize.c	Implements async in-place resize of EC bdevs after base growth.
module/bdev/ec/bdev_ec_bitmap.c	Implements unmapped-bitmap on-disk format, persist/load, and bit-clear queue.
mk/spdk.modules.mk	Registers `bdev_ec` in the global modules list.

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Copilot

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 4 comments.

Copilot

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 3 comments.

c3y1huang · 2026-05-26T11:02:27Z

+	struct ec_bdev *ec = ec_from_bdev_io(ec_io->bdev_io);
+
+	ec_io->is_zero_fill = true;
+	ec->unmaps_via_write_zeros++;
+	return ec_submit_write(ec_io);
+}


This is by design. A single-stripe UNMAP never goes through the native path - it doesn't set bitmap bits or send UNMAP to the base disks; instead, it gets zero-filled (explained in ec_submit_unmap). So the count is not meant to add up. I reworded the comments so the gap doesn't read like a leak.

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

…mitter thread longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

… documentation longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

…b APIs longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

Copilot

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated no new comments.

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

Copilot

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated no new comments.

…s slot longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

c3y1huang self-assigned this May 25, 2026

c3y1huang changed the title ~~bdev/nvme: refresh namespace blockcnt during reset reconnect~~ feat: ec module May 25, 2026

c3y1huang force-pushed the 1061-v2-sharding branch 8 times, most recently from 0bdfee7 to e57455b Compare May 26, 2026 01:17

c3y1huang requested a review from Copilot May 26, 2026 01:31

Copilot started reviewing on behalf of c3y1huang May 26, 2026 01:31 View session

Copilot AI reviewed May 26, 2026

View reviewed changes

c3y1huang force-pushed the 1061-v2-sharding branch 7 times, most recently from 29cbeba to fea1ddd Compare May 26, 2026 04:17

c3y1huang requested a review from Copilot May 26, 2026 04:35

Copilot started reviewing on behalf of c3y1huang May 26, 2026 04:35 View session

Copilot AI reviewed May 26, 2026

View reviewed changes

Comment thread module/bdev/ec/bdev_ec_resize.c

Comment thread module/bdev/ec/bdev_ec_resize.c

Comment thread module/bdev/ec/bdev_ec.c Outdated

Comment thread module/bdev/ec/bdev_ec.c

c3y1huang force-pushed the 1061-v2-sharding branch 4 times, most recently from 4849864 to a9cf467 Compare May 26, 2026 10:10

c3y1huang requested a review from Copilot May 26, 2026 10:12

Copilot started reviewing on behalf of c3y1huang May 26, 2026 10:12 View session

Copilot AI reviewed May 26, 2026

View reviewed changes

c3y1huang added 26 commits June 10, 2026 18:11

bdev/ec: refuse delete while rebuild or resize is active

43c5c11

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: add bdev_ec unit-test suite

5de12bd

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: capture the submitter thread on every bdev_io

b6c1199

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: make cross-thread bitmap and inflight counters atomic

756cebc

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: apply the UNMAP staged shadow via per-stripe release-store

acb7c36

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: assert the submitter thread at every base-I/O dispatch site

07263cb

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: route consumer submit entries to the home thread

494518f

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: split ec_rmw_submit_core into home setup + submitter dispatch

f2e0a5c

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: route the full-stripe write fan-out to the submitter thread

42b726a

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: route the RMW write fan-out to the submitter thread

d006b9f

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: make submitter-incremented counters atomic

b84c856

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: correct the thread-safety rationale on ec_bitmap_apply_buf

5fa050c

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: run the RMW WIB persist before the reads

cfbb319

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: route the RMW read dispatch to the submitter thread

6cd21d2

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: route the write-into-unmapped fan-out to the submitter thread

40a0f8c

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: route the UNMAP base fan-out and inner-completion to the sub…

ba2aa9c

…mitter thread longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: route ec_rmw_complete to the submitter thread

7389df2

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: route the multi-segment UNMAP chain across home and submitter

ccc2205

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: fix wib_buf_bytes overflow on large strip_size

25416e1

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: drop single-reactor framing and finalise the threading-model…

92cea4d

… documentation longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: extract ec_io_release_state to share EC-layer teardown

63ad43f

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: extract ec_scrub_blocks_stripe guard for parity-write paths

6f666b0

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: extract ec_rmw_teardown to share RMW cleanup

3062c17

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: unify background-walk heartbeat between rebuild and scrub

81f6363

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: unify parity reconstruct-then-re-encode helper

8ad157e

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

bdev/ec: adopt struct-returning progress getters for rebuild and scru…

2b7f11e

…b APIs longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

Copilot AI reviewed Jun 10, 2026

View reviewed changes

bdev/ec: drain in-flight persists before releasing dedicated channels

cf271be

longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

Copilot AI reviewed Jun 11, 2026

View reviewed changes

bdev/ec: enforce the WIB stripe ceiling so bitmap I/O stays within it…

8558a87

…s slot longhorn/longhorn-1061 Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

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c3y1huang commented May 25, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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c3y1huang commented May 25, 2026 •

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