feat: support snapshot max count for v2

[davidcheng0922]

Which issue(s) this PR fixes:

longhorn/longhorn#12921

What this PR does / why we need it:

Special notes for your reviewer:

Additional documentation or context

[Copilot]

Pull request overview

This PR adds support for configuring and enforcing a maximum snapshot count for the V2 (SPDK) data engine, aligning instance-manager’s proxy/instance flows with the new SPDK RPC and engine-side enforcement needed for longhorn/longhorn#12921.

Changes:

• Extend V2 instance spec and SPDK RPC to carry SnapshotMaxCount, and plumb it through engine creation and volume get responses.
• Add a new SPDK gRPC method to update an engine’s snapshot max count at runtime, and enforce the limit during snapshot creation.
• Update vendored dependencies and module metadata (currently includes local-path replaces).

Reviewed changes

Copilot reviewed 4 out of 13 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
go.mod	Adds local replace directives for types and longhorn-spdk-engine.
go.sum	Dependency checksum updates/removals from module graph changes.
vendor/modules.txt	Vendor metadata updates; now records local-path replacements.
vendor/github.com/longhorn/types/pkg/generated/spdkrpc/spdk_grpc.pb.go	Adds SPDKService RPC wiring for EngineSnapshotMaxCountSet.
vendor/github.com/longhorn/types/pkg/generated/imrpc/instance.pb.go	Adds snapshot_max_count to SpdkInstanceSpec.
vendor/github.com/longhorn/longhorn-spdk-engine/pkg/spdk/server_engine.go	Plumbs SnapshotMaxCount into engine creation and adds server handler for updating it.
vendor/github.com/longhorn/longhorn-spdk-engine/pkg/spdk/engine.go	Stores SnapshotMaxCount, exposes it via EngineGet, and enforces it in snapshot precheck.
vendor/github.com/longhorn/longhorn-spdk-engine/pkg/client/client_engine.go	Extends EngineCreate and adds EngineSnapshotMaxCountSet client call.
vendor/github.com/longhorn/longhorn-spdk-engine/pkg/api/types.go	Exposes SnapshotMaxCount in the API engine struct conversion.
pkg/instance/instance.go	Passes SnapshotMaxCount into SPDK engine creation for V2 instances.
pkg/client/instance.go	Adds SnapshotMaxCount to engine create request and maps it into SpdkInstanceSpec.
pkg/proxy/volume.go	Returns SnapshotMaxCount for V2 in VolumeGet and implements V2 VolumeSnapshotMaxCountSet.

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[derekbit]

LGTM

[derekbit]

@mergify backport v1.12.x

[mergify]

backport v1.12.x

✅ Backports have been created

Details

• #1394 feat: support snapshot max count for v2 (backport #1391) has been created for branch v1.12.x but encountered conflicts

Cherry-pick of 1ecf693 has failed:

On branch mergify/bp/v1.12.x/pr-1391
Your branch is up to date with 'origin/v1.12.x'.

You are currently cherry-picking commit 1ecf693e.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   pkg/client/instance.go
	modified:   pkg/instance/instance.go
	modified:   pkg/proxy/volume.go
	modified:   vendor/github.com/longhorn/longhorn-spdk-engine/pkg/api/types.go
	modified:   vendor/github.com/longhorn/longhorn-spdk-engine/pkg/client/client_engine.go
	modified:   vendor/github.com/longhorn/longhorn-spdk-engine/pkg/spdk/engine.go
	modified:   vendor/github.com/longhorn/longhorn-spdk-engine/pkg/spdk/server_engine.go
	modified:   vendor/github.com/longhorn/types/pkg/generated/imrpc/instance.pb.go
	modified:   vendor/github.com/longhorn/types/pkg/generated/spdkrpc/spdk.pb.go
	modified:   vendor/github.com/longhorn/types/pkg/generated/spdkrpc/spdk_grpc.pb.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   go.mod
	both modified:   go.sum
	both modified:   vendor/modules.txt

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally